Tiny details in three dimensions
They are borne by ticks and can cause acute and chronic symptoms in joints, muscles and the nervous system - the bacteria that cause Lyme borreliosis, which 80,000 people in Germany contract every year. Heidelberg researchers have now succeeded in identifying their structure more accurately. Using a cryo-tomography microscope, the previously unknown detailed structure of the spirochete bacteria can be shown in three dimensions. One finding - that borrelia types in North America more often affect the joints and in Europe the skin and nervous system as well - seems to stem from the characteristics of their motility system.
The research group headed by Professor Reinhard Wallich, Institute of Immunology, and Dr. Friedrich Frischknecht, Department of Parasitology at the Hygiene Institute of Heidelberg University Hospital has published its findings in cooperation with colleagues from Munich and Freiburg in "Molecular Microbiology". Among other things, the researchers hope to gain new insights into the various clinical symptoms of the disease.
Shock freezing maintains original condition / Resolution up to 5 nanometers
In cryo-electron tomography the organism is shock frozen so that its original condition is retained. Chemical pretreatment, which is often associated with modifying structures and properties, is no longer necessary. Resolution of five to seven nm allows tiniest structures to be viewed. "The new technology is a quantum leap for research, comparable with the step from simple x-ray images to three-dimensional computer tomography in clinical diagnostics," stated Dr. Frischknecht.
The bacteria have developed many strategies to avoid the immune response of humans. Borrelias, like the syphilis pathogens, are spirochetes bacteria. The spiral-shaped, actively motile bacteria have flexible, pliable bodies that are moved with the aid of complex organs, flagella. A correlation between the motility and infectiousness of the pathogen has long been presumed.
The Heidelberg researchers have now for the first time compared the characteristics of the three human pathogenic species that cause Lyme borreliosis that occur in Europe and cause varying symptoms. While in North America, the major symptom is joint inflammation, in Europe, the skin or nervous system may also be affected. With the aid of cryo-tomographic microscopy, they have successfully shown that the three pathogen types have varying numbers of flagella. In addition, structures were identified for the first time that could play an important role in the reproduction of the bacteria.
References:
Comparative cryo-electron tomography of pathogenic Lyme disease spirochetes
Mikhail Kudryashev, Marek Cyrklaff, Wolfgang Baumeister, Markus M. Simon, Reinhard Wallich, Friedrich Frischknecht
Published Online: Feb 4 2009 7:27AM
DOI: 10.1111/j.1365-2958.2009.06613.x
More information on the Internet:
klinikum.uni-heidelberg/Immunologie.106593.0.html
Contacts:
Dr. Friedrich Frischknecht
Heidelberg University Hospital
Hygiene Institute
Department of Parasitology
Im Neuenheimer Feld 324
69120 Heidelberg
Prof. Dr. Reinhard Wallich
Heidelberg University Hospital
Institute of Infection Immunology
Im Neuenheimer Feld 305
69120 Heidelberg
Heidelberg University Hospital and School of Medicine
Health care, research, and teaching of international reputation. The Heidelberg University Hospital is one of the largest and most prestigious medical centers in Germany; the medical school at Heidelberg University is an internationally renowned biomedical research institute in Europe. Their common goal is to develop new therapies and implement them quickly in patient care. Hospital and medical school employ around 7,000 people and are active in training and qualification. In more than 40 clinics and departments with 1,600 beds, some 500,000 in and outpatients are seen and treated every year. Currently, approx. 1,300 future physicians are studying in Heidelberg; the Heidelberg Curriculum Medicinale (HeiCuMed) is the top medical training program in Germany. (as of 12/2008)
klinikum.uni-heidelberg/
Source: Dr. Friedrich Frischknecht
University Hospital Heidelberg
суббота, 30 апреля 2011 г.
пятница, 29 апреля 2011 г.
Novel Way To Remove Iron From Ferritin Discovered By Scientists
A new study led by Children's Hospital Oakland Research Institute senior scientist, Elizabeth Theil, Ph.D., is the first to suggest that a small protein or heptapeptide (seven amino acids wrapped into one unit) could be used to accelerate the removal of iron from ferritin. The results of this study may help scientists develop new medications that dramatically improve the removal of excess iron in patients diagnosed with blood diseases such as B-Thalassemia (Cooley's anemia) or Sickle Cell Disease.
The study appears in this month's issue of the Journal of Biological Chemistry and was conducted by Dr. Theil and her co-authors Xiaofeng S. Liu, postdoctoral fellow at Children's Hospital Oakland Research Institute, Marvin J. Miller, Ph.D. and Leslie D. Patterson, a predoctoral student, both from the University of Notre Dame. The scientists knew that the ferritin protein cage had pores that could open and close. It was also known that chelators (a method to detoxify blood) removed iron faster when the pores were open.
"We wanted to prove a hypothesis that a small protein or peptide could bind to ferritin and could be used to regulate ferritin pores," said Dr. Theil. "Our hypothesis was correct. We proved that when a binding peptide of seven amino acids, a heptapeptide, is coupled with Desferal the rate of removal of iron from ferritin is eight times faster." Desferal is currently used to detoxify the blood of patients with iron overload and is a common therapeutic remedy.
Ferritin is a protein that concentrates iron in its inner core or 'cage'. It plays a critical role in understanding iron overload, which can lead to a variety of symptoms including chronic fatigue, weakness, joint pain and arthritis. If left untreated, iron overload can lead to serious problems, including diabetes, liver and heart disease.
The study's results are based on laboratory tests. The National Institutes of Health (NIH), the Cooley's Anemia Foundation and Children's Hospital & Research Center Oakland provided funding for this research.
Click here for more information on Dr. Theil's research.
Research at Children's Hospital & Research Center Oakland, CA
Research efforts at Children's Hospital & Research Center Oakland are coordinated through Children's Hospital Oakland Research Institute (CHORI). Children's Hospital Oakland is Northern California's only freestanding and independent children's hospital. CHORI's internationally renowned biomedical research facility brings together seven centers of excellence that are devoted to clinical and basic science research to treat and prevent disease. CHORI has approximately 300 staff members and an annual budget of more than $49 million. The National Institutes of Health is CHORI's primary funding source. The institute is a leader in translational research, bringing bench discoveries to bedside applications. These include providing cures for blood diseases, developing new vaccines for infectious diseases and discovering new treatment protocols for previously fatal or debilitating conditions such as cancers, sickle cell disease and thalassemia, diabetes, asthma, HIV/AIDS, pediatric obesity, nutritional deficiencies, birth defects, hemophilia and cystic fibrosis.
Source: Venita Robinson
Children's Hospital & Research Center at Oakland
The study appears in this month's issue of the Journal of Biological Chemistry and was conducted by Dr. Theil and her co-authors Xiaofeng S. Liu, postdoctoral fellow at Children's Hospital Oakland Research Institute, Marvin J. Miller, Ph.D. and Leslie D. Patterson, a predoctoral student, both from the University of Notre Dame. The scientists knew that the ferritin protein cage had pores that could open and close. It was also known that chelators (a method to detoxify blood) removed iron faster when the pores were open.
"We wanted to prove a hypothesis that a small protein or peptide could bind to ferritin and could be used to regulate ferritin pores," said Dr. Theil. "Our hypothesis was correct. We proved that when a binding peptide of seven amino acids, a heptapeptide, is coupled with Desferal the rate of removal of iron from ferritin is eight times faster." Desferal is currently used to detoxify the blood of patients with iron overload and is a common therapeutic remedy.
Ferritin is a protein that concentrates iron in its inner core or 'cage'. It plays a critical role in understanding iron overload, which can lead to a variety of symptoms including chronic fatigue, weakness, joint pain and arthritis. If left untreated, iron overload can lead to serious problems, including diabetes, liver and heart disease.
The study's results are based on laboratory tests. The National Institutes of Health (NIH), the Cooley's Anemia Foundation and Children's Hospital & Research Center Oakland provided funding for this research.
Click here for more information on Dr. Theil's research.
Research at Children's Hospital & Research Center Oakland, CA
Research efforts at Children's Hospital & Research Center Oakland are coordinated through Children's Hospital Oakland Research Institute (CHORI). Children's Hospital Oakland is Northern California's only freestanding and independent children's hospital. CHORI's internationally renowned biomedical research facility brings together seven centers of excellence that are devoted to clinical and basic science research to treat and prevent disease. CHORI has approximately 300 staff members and an annual budget of more than $49 million. The National Institutes of Health is CHORI's primary funding source. The institute is a leader in translational research, bringing bench discoveries to bedside applications. These include providing cures for blood diseases, developing new vaccines for infectious diseases and discovering new treatment protocols for previously fatal or debilitating conditions such as cancers, sickle cell disease and thalassemia, diabetes, asthma, HIV/AIDS, pediatric obesity, nutritional deficiencies, birth defects, hemophilia and cystic fibrosis.
Source: Venita Robinson
Children's Hospital & Research Center at Oakland
четверг, 28 апреля 2011 г.
Adjustable Chairs Reduce Shoulder And Neck Pain In Garment Workers
Adjustable-height chairs with ergonomically curved seats can significantly reduce neck and shoulder pain in garment workers, according to a new study in Spine.
The study shows that chair design affects neck and shoulder pain among garment workers -- and possibly in other laborers engaged in visually intensive manufacturing work, the researchers say.
The study was led by David Rempel, MD, MPH, director of the ergonomics program at San Francisco General Hospital and professor of medicine at the University of California, San Francisco; and Beate Ritz, MD, PhD, associate professor of epidemiology, at University of California, Los Angeles.
According to the authors, garment workers typically work in a seated position for seven to 10 hours per day, using their hands to manipulate cloth or to complete fine-motor tasks while sewing. The work is visually intensive, so workers often lean forward and hold their arms and shoulders up. In 2000, the garment industry employed 11 million workers worldwide. Approximately 350,000 of these workers were in the United States. Los Angeles is the home of the largest garment production center in the country.
"Garment workers have not been the focus of many studies, despite the fact that they face important occupational health risks," Rempel explained. "Their work is physically demanding, especially on the upper extremities and neck."
In an earlier pilot study, Rempel and colleagues from UCSF tested a number of interventions, including a chair they designed, to relieve neck and shoulder pain in garment workers in the Bay Area.
The custom-designed chair is height adjustable, has no wheels, in order to ensure the garment workers stay seated firmly in place, has no arm supports to interfere with movements, and has a seat pan that slants slightly downward to support forward-leaning postures. The chair is also upholstered with a breathable cloth and foam appropriate for the high-temperature environment of the garment shop floor. The researchers found that the custom-made chair reduced risk factors for shoulder and neck pain better than the other interventions tested.
In the current study, the researchers evaluated the effectiveness of the custom-made chair in comparison to two more traditional chairs -- an adjustable height, flat seat pan chair, and a fixed-height, flat seat pan chair commonly used by garment workers in the United States.
For this study, they recruited 277 sewing machine operators with neck and shoulder pain who worked at least twenty hours a week in one of 13 garment shops in the Los Angeles area.
All subjects were given miscellaneous items that may or may not aid in reduction of pain, including table-top storage boxes for work tools, side tables to help manage cloth, task lamps and reading glasses. These items could be used or rejected at will.
The subjects were then randomly assigned to receive one of the three types of chairs. Results showed participants who sat in an adjustable height, flat-seat pan chair experienced a reduction in pain of 0.14 points on a 0-5 scale per month compared to a control group, while those who received the custom-designed chair experienced a decline in pain of 0.34 points per month compared to those in the control group. Results also showed the effect was more prominent in thin workers and in those whose workloads involved more hand and arm work.
"Both types of height adjustable chairs significantly decreased neck pain among the garment workers over a four-month period, but the curved seat pan provided more benefit than the flat seat pan chair," Rempel said. "These findings indicate that owners of sewing companies should consider providing an adjustable height chair with a forward sloped seat pan for their employees as a way of reducing pain and loss of trained workers due to impaired health."
In order to evaluate the chair design in other industrial settings, the research group is currently looking for other workplaces with hand-intensive manufacturing jobs to study.
"We feel strongly that garment workers and other manufacture laborers are a particularly important group to evaluate and help because they are largely an immigrant population without access to health care or workers' compensation," added Rempel.
Staff from the California Occupational Health Program of the California Department of Health Services were also involved in this study.
The study was supported by a grant from the Centers for Disease Control, National Institutes for Occupational Safety and Health. The study authors have no financial interest in the chairs studied.
UCSF is a leading university that advances health worldwide by conducting advanced biomedical research, educating graduate students in the life sciences and health professions, and providing complex patient care.
Contact: Vanessa deGier
University of California - San Francisco
The study shows that chair design affects neck and shoulder pain among garment workers -- and possibly in other laborers engaged in visually intensive manufacturing work, the researchers say.
The study was led by David Rempel, MD, MPH, director of the ergonomics program at San Francisco General Hospital and professor of medicine at the University of California, San Francisco; and Beate Ritz, MD, PhD, associate professor of epidemiology, at University of California, Los Angeles.
According to the authors, garment workers typically work in a seated position for seven to 10 hours per day, using their hands to manipulate cloth or to complete fine-motor tasks while sewing. The work is visually intensive, so workers often lean forward and hold their arms and shoulders up. In 2000, the garment industry employed 11 million workers worldwide. Approximately 350,000 of these workers were in the United States. Los Angeles is the home of the largest garment production center in the country.
"Garment workers have not been the focus of many studies, despite the fact that they face important occupational health risks," Rempel explained. "Their work is physically demanding, especially on the upper extremities and neck."
In an earlier pilot study, Rempel and colleagues from UCSF tested a number of interventions, including a chair they designed, to relieve neck and shoulder pain in garment workers in the Bay Area.
The custom-designed chair is height adjustable, has no wheels, in order to ensure the garment workers stay seated firmly in place, has no arm supports to interfere with movements, and has a seat pan that slants slightly downward to support forward-leaning postures. The chair is also upholstered with a breathable cloth and foam appropriate for the high-temperature environment of the garment shop floor. The researchers found that the custom-made chair reduced risk factors for shoulder and neck pain better than the other interventions tested.
In the current study, the researchers evaluated the effectiveness of the custom-made chair in comparison to two more traditional chairs -- an adjustable height, flat seat pan chair, and a fixed-height, flat seat pan chair commonly used by garment workers in the United States.
For this study, they recruited 277 sewing machine operators with neck and shoulder pain who worked at least twenty hours a week in one of 13 garment shops in the Los Angeles area.
All subjects were given miscellaneous items that may or may not aid in reduction of pain, including table-top storage boxes for work tools, side tables to help manage cloth, task lamps and reading glasses. These items could be used or rejected at will.
The subjects were then randomly assigned to receive one of the three types of chairs. Results showed participants who sat in an adjustable height, flat-seat pan chair experienced a reduction in pain of 0.14 points on a 0-5 scale per month compared to a control group, while those who received the custom-designed chair experienced a decline in pain of 0.34 points per month compared to those in the control group. Results also showed the effect was more prominent in thin workers and in those whose workloads involved more hand and arm work.
"Both types of height adjustable chairs significantly decreased neck pain among the garment workers over a four-month period, but the curved seat pan provided more benefit than the flat seat pan chair," Rempel said. "These findings indicate that owners of sewing companies should consider providing an adjustable height chair with a forward sloped seat pan for their employees as a way of reducing pain and loss of trained workers due to impaired health."
In order to evaluate the chair design in other industrial settings, the research group is currently looking for other workplaces with hand-intensive manufacturing jobs to study.
"We feel strongly that garment workers and other manufacture laborers are a particularly important group to evaluate and help because they are largely an immigrant population without access to health care or workers' compensation," added Rempel.
Staff from the California Occupational Health Program of the California Department of Health Services were also involved in this study.
The study was supported by a grant from the Centers for Disease Control, National Institutes for Occupational Safety and Health. The study authors have no financial interest in the chairs studied.
UCSF is a leading university that advances health worldwide by conducting advanced biomedical research, educating graduate students in the life sciences and health professions, and providing complex patient care.
Contact: Vanessa deGier
University of California - San Francisco
среда, 27 апреля 2011 г.
Promising Results In Reducing Neuropathic Pain With Combined Drug Treatment, Than With Either Drug Alone
An article published Online First and in a future edition of The Lancet reports that combination treatment using gabapentin and nortriptyline reduces neuropathic pain more than either drug alone. This treatment could be used in patients that only partly respond to one drug or the other. The article is the work of Professor Ian Gilron, Director of Clinical Pain Research, Queen's University, and Kingston General Hospital, Kingston, Ontario, Canada, and colleagues.
Neuropathic pain has been defined as pain "initiated or caused by a primary lesion or dysfunction in the nervous system." It affects more than 2 to 3 percent of the general population. Disorders causing neuropathic pain include nerve problems in the spine; diabetic polyneuropathy, in which damage to blood vessels in diabetes also causes damage to nerves; and postherpetic neuralgia (PHN) which is a nerve pain caused by the varicella zoster virus which can follow an outbreak of shingles. Gabapentin is an anticonvulsant and nortriptyline is an antidepressant. They are two of several first line drugs with the most positive therapeutic profiles. However, when given as monotherapy, the maximum tolerated doses of these drugs hardly ever reduce pain by more than 60 percent. In addition, they provide relief in only 40 to 60 percent of patients because of partial efficacy and dose-limiting side-effects. The authors in this study evaluated the efficacy and tolerability of combined nortriptyline and gabapentin compared with each drug given alone.
A total of 56 patients with diabetic polyneuropathy or postherpetic neuralgia were included in this randomised controlled trial. They had a daily pain score of at least 4 (scale 0 to 10) and were enrolled and treated at one site in Canada between November 2004 and December 2007. Patients were assigned in a 1:1:1 ratio to one of three sequences of daily oral gabapentin, nortriptyline, and their combination. In series, a different drug was given to each randomised group in three treatment periods. This trial is referred to as a 'crossover' design. All patients get to try all three treatments and each patient serves as his/her own control. During each of three six-week treatment periods, drug doses were gradually increased towards maximum tolerated dose. The primary outcome was an average daily pain at maximum tolerated dose.
Results indicated that 45 patients completed all three treatment periods; 47 patients completed at least two treatment periods and were analysed for the primary outcome. Mean daily pain was 5•4 at baseline, and at maximum tolerated dose, pain was 3•2 for gabapentin, 2•9 for nortriptyline, and 2•3 for combination treatment. Pain with combination treatment was considerably lower than with gabapentin (-0•9) or nortriptyline alone (-0•6). At maximum tolerated dose, the most frequent adverse event was dry mouth, which was significantly less frequent in patients on gabapentin than on nortriptyline or combination treatment. During the trial, there were no serious adverse events recorded for any patients.
The authors write in conclusion: "This trial shows that combination of an antidepressant and an anticonvulsant drug seems to be superior to monotherapy for neuropathic pain... Although development of more effective and better tolerated monotherapies is much anticipated, our findings suggest that drug combinations represent the most effective strategy for many patients with neuropathic pain. On the basis of our results, we recommend combined gabapentin and nortriptyline for patients who have a partial response to either drug alone and seek additional pain relief."
In an associated note, Dr Troels Staehelin Jensen, Department of Neurology, Aarhus University Hospital, and Dr Nanna Brix Finnerup, Danish Pain Research Center, Aarhus University Hospital, Denmark, define Gilron and colleagues' proposal to use the two drugs in this way as 'a logical step forward'.
"Nortriptyline and gabapentin, alone and in combination for neuropathic pain: a double-blind, randomised controlled crossover trial"
Ian Gilron, Joan M Bailey, Dongsheng Tu, Ronald R Holden, Alan C Jackson, Robyn L Houlden
DOI: 10.1016/S0140-6736(09)61081-3
The Lancet
Written by Stephanie Brunner (B.A.)
Neuropathic pain has been defined as pain "initiated or caused by a primary lesion or dysfunction in the nervous system." It affects more than 2 to 3 percent of the general population. Disorders causing neuropathic pain include nerve problems in the spine; diabetic polyneuropathy, in which damage to blood vessels in diabetes also causes damage to nerves; and postherpetic neuralgia (PHN) which is a nerve pain caused by the varicella zoster virus which can follow an outbreak of shingles. Gabapentin is an anticonvulsant and nortriptyline is an antidepressant. They are two of several first line drugs with the most positive therapeutic profiles. However, when given as monotherapy, the maximum tolerated doses of these drugs hardly ever reduce pain by more than 60 percent. In addition, they provide relief in only 40 to 60 percent of patients because of partial efficacy and dose-limiting side-effects. The authors in this study evaluated the efficacy and tolerability of combined nortriptyline and gabapentin compared with each drug given alone.
A total of 56 patients with diabetic polyneuropathy or postherpetic neuralgia were included in this randomised controlled trial. They had a daily pain score of at least 4 (scale 0 to 10) and were enrolled and treated at one site in Canada between November 2004 and December 2007. Patients were assigned in a 1:1:1 ratio to one of three sequences of daily oral gabapentin, nortriptyline, and their combination. In series, a different drug was given to each randomised group in three treatment periods. This trial is referred to as a 'crossover' design. All patients get to try all three treatments and each patient serves as his/her own control. During each of three six-week treatment periods, drug doses were gradually increased towards maximum tolerated dose. The primary outcome was an average daily pain at maximum tolerated dose.
Results indicated that 45 patients completed all three treatment periods; 47 patients completed at least two treatment periods and were analysed for the primary outcome. Mean daily pain was 5•4 at baseline, and at maximum tolerated dose, pain was 3•2 for gabapentin, 2•9 for nortriptyline, and 2•3 for combination treatment. Pain with combination treatment was considerably lower than with gabapentin (-0•9) or nortriptyline alone (-0•6). At maximum tolerated dose, the most frequent adverse event was dry mouth, which was significantly less frequent in patients on gabapentin than on nortriptyline or combination treatment. During the trial, there were no serious adverse events recorded for any patients.
The authors write in conclusion: "This trial shows that combination of an antidepressant and an anticonvulsant drug seems to be superior to monotherapy for neuropathic pain... Although development of more effective and better tolerated monotherapies is much anticipated, our findings suggest that drug combinations represent the most effective strategy for many patients with neuropathic pain. On the basis of our results, we recommend combined gabapentin and nortriptyline for patients who have a partial response to either drug alone and seek additional pain relief."
In an associated note, Dr Troels Staehelin Jensen, Department of Neurology, Aarhus University Hospital, and Dr Nanna Brix Finnerup, Danish Pain Research Center, Aarhus University Hospital, Denmark, define Gilron and colleagues' proposal to use the two drugs in this way as 'a logical step forward'.
"Nortriptyline and gabapentin, alone and in combination for neuropathic pain: a double-blind, randomised controlled crossover trial"
Ian Gilron, Joan M Bailey, Dongsheng Tu, Ronald R Holden, Alan C Jackson, Robyn L Houlden
DOI: 10.1016/S0140-6736(09)61081-3
The Lancet
Written by Stephanie Brunner (B.A.)
вторник, 26 апреля 2011 г.
What Exactly Is Repetitive Strain Injury?
High quality trials and evidence of effective treatments for repetitive strain injury (RSI) are needed to define this controversial condition which affects millions of patients worldwide. The findings are reported in a Seminar published in The Lancet.
Professor Maurits van Tulder, EMGO Institute, VU University Medical Centre, Amsterdam, Netherlands and colleagues did extensive research into the prevalence, causes, symptoms, and treatments of RSI using a number of medical databases.
The authors say: "Repetitive strain injury is not one diagnosis, but is an umbrella term for disorders that develop as a result of repetitive movements, awkward postures, sustained force, and other risk factors."
Conventional definitions of RSI include specific disorders such as carpal tunnel syndrome (a twisting of the median nerve at the wrist causing pain in the wrist and hand), tendonitis of the wrist and hand, and various upper limb problems.
RSI arises frequently in adults of working age, with many people reporting strains of the hands, wrists, arms, shoulders or neck. Several countries report RSI incidence of 5-10%, although this could be as high as 40% in specific working populations.
Several hypotheses exist for how RSI occurs, but none have been supported by strong scientific evidence. One theory is that continuous contraction of muscles from long term static load with insufficient breaks could result in reduced local blood circulation and muscle fatigue. Consequently, pain sensors in the muscles could become over-sensitive, leading to a feeling of pain at lower-than-normal thresholds. Another theory is that overuse of tendons by repetitive loading causes RSI.
Diagnosis is often a difficult proposition. The authors say: "No gold standard tests for repetitive strain injury exist. In most cases, diagnosis is made on the basis of history and physical examination, including assessment of range of motion of joints, hypermobility, muscle tenderness, pain, strength, and imbalance between right and left limbs."
Doctors can also find it difficult to suggest appropriate treatment for RSI, although several studies have shown exercise to be beneficial both for providing symptom relief and improving the activities of daily living.
Other treatments such as massage or use of ergonomic keyboards at workstations are also regularly prescribed; however three separate studies into these non-proven techniques did not reduce sick leave in patients who tried them, and so none of these individual other treatments can be specifically recommended.
The authors conclude: "Strong recommendations for any therapeutic intervention cannot be made at present because many trials have small sample sizes and methodological flaws that could have led to biased results.
"This disorder will remain controversial until high-quality trials provide clear definition of repetitive strain injury and evidence of effective treatments."
Contact: Maurits van Tulder
Lancet
Professor Maurits van Tulder, EMGO Institute, VU University Medical Centre, Amsterdam, Netherlands and colleagues did extensive research into the prevalence, causes, symptoms, and treatments of RSI using a number of medical databases.
The authors say: "Repetitive strain injury is not one diagnosis, but is an umbrella term for disorders that develop as a result of repetitive movements, awkward postures, sustained force, and other risk factors."
Conventional definitions of RSI include specific disorders such as carpal tunnel syndrome (a twisting of the median nerve at the wrist causing pain in the wrist and hand), tendonitis of the wrist and hand, and various upper limb problems.
RSI arises frequently in adults of working age, with many people reporting strains of the hands, wrists, arms, shoulders or neck. Several countries report RSI incidence of 5-10%, although this could be as high as 40% in specific working populations.
Several hypotheses exist for how RSI occurs, but none have been supported by strong scientific evidence. One theory is that continuous contraction of muscles from long term static load with insufficient breaks could result in reduced local blood circulation and muscle fatigue. Consequently, pain sensors in the muscles could become over-sensitive, leading to a feeling of pain at lower-than-normal thresholds. Another theory is that overuse of tendons by repetitive loading causes RSI.
Diagnosis is often a difficult proposition. The authors say: "No gold standard tests for repetitive strain injury exist. In most cases, diagnosis is made on the basis of history and physical examination, including assessment of range of motion of joints, hypermobility, muscle tenderness, pain, strength, and imbalance between right and left limbs."
Doctors can also find it difficult to suggest appropriate treatment for RSI, although several studies have shown exercise to be beneficial both for providing symptom relief and improving the activities of daily living.
Other treatments such as massage or use of ergonomic keyboards at workstations are also regularly prescribed; however three separate studies into these non-proven techniques did not reduce sick leave in patients who tried them, and so none of these individual other treatments can be specifically recommended.
The authors conclude: "Strong recommendations for any therapeutic intervention cannot be made at present because many trials have small sample sizes and methodological flaws that could have led to biased results.
"This disorder will remain controversial until high-quality trials provide clear definition of repetitive strain injury and evidence of effective treatments."
Contact: Maurits van Tulder
Lancet
понедельник, 25 апреля 2011 г.
What Is Repetitive Strain Injury (RSI)? What Causes Repetitive Strain Injury?
Repetitive strain injury or RSI, also known as repetitive stress injury, repetitive motion injuries, repetitive motion disorder (RMD), cumulative trauma disorder (CTD), occupational overuse syndrome, overuse syndrome, and regional musculoskeletal disorder is a range of painful or uncomfortable conditions of the muscles, tendons, nerves and other soft tissues. RSI is usually caused by repetitive use of a certain part of the body, often somewhere in the upper limbs (arms).
Repetitive strain injury is typically related to an occupation (job), but may also be linked to some kinds of leisure activity. As opposed to a sudden or 'normal' injury, RSI signs and symptoms may continue for much longer.
Experts say that repetitive strain injury is an injury of the musculoskeletal and nervous systems that may be the result of repetitive tasks, forceful exertions, vibrations, pressing against hard surfaces (mechanical compression), or sustained or awkward positions. Conditions such as RSI tend to be linked to both physical and psychosocial stressors (mental stress).
A US study found that acute and sudden computer-related injuries, a separate category to injuries that take a while to emerge like repetitive strain injury, are rising rapidly in the US, and that young children are most affected.
Many health care professionals refer to RSI as ULD (upper limb disorder) because it frequently involves the forearm, elbow, wrist or hands. RSI often affects the neck as well.
The following are examples of repetitive strain injuries:
Bursitis - happens when the bursa is inflamed. The bursa acts as a cushion between bones, tendons, joints and muscles - bursae are fluid-filled sacs (the plural of bursa is bursae). People with bursitis will feel pain at the site of inflammation.
Carpal tunnel syndrome (CTS) - caused by the compression of the median nerve through the carpal tunnel in the wrist area. When constricted, blood cannot flow freely through the hand to the fingers causing individuals with CTS to experience numbness and pain in the hand.
Diffuse RSI - conditions are where the patient complains of pain and yet, on examination by a health care professional, nothing physical can be found to be wrong.
Dupuytren's contracture - a condition that affects the hands and fingers. It is an uncommon hand deformity in which the connective tissue under the skin of the palm contract and toughen over time. It causes one or more of the fingers on one or both hands to bend into the palm of the hand.
Epicondylitis - often occurs as a result of strenuous overuse of the muscles and tendons where the bone and tendon join. Tennis elbow and golfer's elbow are examples.
Ganglion - fluid-filled swellings that tend to form on top of joints or tendons in the wrists, hands, and feet. They have the appearance of firm or spongy sacs of liquid and their insides consist of a sticky, clear, thick, jelly-like fluid.
Rotator cuff syndrome - inflammation of tendons and muscles in the shoulder.
Tendinitis - also known as tendonitis, is the inflammation of a tendon.
Tenosynovitis - the sheath around the tendon becomes inflamed, specifically the inner lining of the tendon sheath.
Trigger finger - a condition in which one of your fingers or your thumb catches in a bent position. The tendon sheaths of the fingers or thumb become inflamed - the tendon is also inflamed.
RSI is frequently caused by such activities as golf or tennis - activities which require repetitive movements. Signs and symptoms generally persist if left untreated. Experts say that the number of people experiencing RSI as a result of computer use has been increasing for many years. RSI that is caused by typing on a computer keyboard is often referred to as writer's cramp.
Experts often refer to two main types of RSI:
Type 1 RSI - usually caused by repetitive tasks, but not always; some people who do not perform repetitive tasks may have Type 1 RSI. The muscles and tendons swell. Examples of Type 1 RSI include:
Carpal tunnel syndrome
Tendinitis (tendonitis)
Tenosynovitis
Type 2 RSI - there is a feeling of pain but no obvious inflammation or swelling in the area where symptoms are felt. The National Health Service (NHS), UK, refers to Type 2 RSI "when a person's symptoms do not fit into one of the (above listed) conditions". Also called non-specific pain syndrome.
What are the signs and symptoms of repetitive strain injury (RSI)?
A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor detect. For example, pain may be a symptom while a rash may be a sign.
Signs and symptoms vary, depending on which part of the body is affected, and what caused the problem in the first place. Initially, symptoms may only occur when the individual is doing the repetitive task - they will slowly go away when the person rests. Eventually, though, symptoms may be present all the time (and worsen during the repetitive task) if left untreated.
The most common RSI signs and symptoms include:
Tenderness in the affected muscle or joint
Pain in the affected muscle or joint
A throbbing (pulsating) sensation in the affected area
Pins and needles (tingling) in the affected area, especially the hand or arm
Loss of sensation in the hand
Loss of strength in the hand
Some patients with persistent symptoms may have sleeping problems - the condition is often irreversible at this stage. Early treatment is much more likely to prevent any irreversible damage.
What are the causes of repetitive strain injury (RSI)?
Experts say the causes of RSI are a bit of a mystery. Sometimes there is no swelling in the muscles or tendons, but the patient feels pain and discomfort. We know that often repetitive movements of a part of the body are linked to symptoms - movements, such as typing, using a computer mouse, poor posture while doing a movement, using excessive force, doing the repetitive movements without sufficient breaks, etc. But the precise reason for RSI is not clear. Neither do we know why some people develop RSI and others don't, when doing the same tasks for similar periods.
Some studies indicate that some psycho-social workplace factors, such as stress may be significant contributory factors to RSI. Perhaps stress affects our muscles (makes them tense), which in turn makes us more sensitive to pain.
The following are seen as causes of RSI:
The overuse of muscles in our hands, wrists, arms, shoulders, neck and back are linked to RSI symptoms.
The area is affected by repeated actions, which are usually performed on a daily basis over a long period.
The repetitive actions are done in a cold place.
The individual has to use vibrating equipment.
Forceful movements are involved.
Workstations are poorly organized.
Equipment is badly designed.
The individual commonly adopts an awkward posture.
There are not enough rest breaks.
How is repetitive strain injury (RSI) diagnosed?
There is no objective way to diagnose RSI - there are no tests to confirm a diagnosis. Signs and symptoms could be caused by a wide range of factors.
A health care professional will usually diagnose RSI if the signs and symptoms can be linked to a specific repetitive task, and the symptoms lessen when the task is stopped.
If the patient develops a definable condition, such as frozen shoulder, carpal tunnel syndrome or tendinitis, it may or may not be linked to repetitive tasks.
What are the treatment options for repetitive strain injury (RSI)?
The National Health Service (NHS), UK, advises people to see their doctor as soon as they experience symptoms. Early treatment is more likely to result in effective outcomes.
A GP (general practitioner, primary care physician) will probably ask the patient to stop doing the repetitive movements which may be causing the symptoms. If this is not possible, as may be the case with work-related activities, the individual needs to tell his/her employer.
The aim of treatment is to help ease the pain, and to enable the patient to gain strength and mobility in the affected area.
Pain relief - a course of anti-inflammatory painkillers, such as ibuprofen or aspirin may help. Children under 16 years of age should not take aspirin. The following may also help:
Use of heat (applying heat to the affected area)
Cold packs
Elastic supports
Firm splints
Steroid injections - these may be administered if there is a well defined inflammation in the affected area.
Sleep - if the patient is having sleeping problems the doctor may prescribe a short course of sleeping tablets. Good sleep may help relax the patient and alter his/her perception and susceptibility to pain.
Physical therapy (UK: physiotherapy), exercise and relaxation techniques - a physical therapist (UK: physiotherapist) may help the patient adopt proper posture, as well as teaching him/her to strengthen muscles. Electrotherapy may also be used - small electrical impulses are placed at specific points of the body to help reduce pain. The following may also provide benefits:
Walking
Swimming
A Danish study found that five exercises reduced neck pain for women office workers.
Yoga
Tai chi
Mediation and relaxation techniques
Some say the "Alexander Technique" helps
Scientists at the University of British Columbia, Canada, found that "physical activity is associated with a lower risk of work-related repetitive strain injury".
Occupational Therapy - by analyzing the following factors with the help of an occupational therapist, there may be ways of adopting measures to reduce symptoms:
Working with a computer - is your equipment positioned properly. Are your seat, keyboard and mouse positioned in the best way to minimize strain on your hands, fingers, arms, back and neck. Adaptive technology, such as special keyboards, mouse replacements, pen tablets interfaces, and speech recognition software may help.
Posture - are you sitting correctly?
Breaks - when doing repetitive tasks are you getting enough breaks? There is software that reminds computer users it is time to have a break.
Work environment - is there anything your employer might do to improve your working environment?
Stress - is there anything you can do to alleviate (treat) your level of stress?
Many patients experience reduced symptoms, or total elimination of symptoms if prevention and treatment measures are carried out. Others, however, continue to suffer regardless. Unfortunately, there are cases of people having to leave/change their jobs.
Written by
Repetitive strain injury is typically related to an occupation (job), but may also be linked to some kinds of leisure activity. As opposed to a sudden or 'normal' injury, RSI signs and symptoms may continue for much longer.
Experts say that repetitive strain injury is an injury of the musculoskeletal and nervous systems that may be the result of repetitive tasks, forceful exertions, vibrations, pressing against hard surfaces (mechanical compression), or sustained or awkward positions. Conditions such as RSI tend to be linked to both physical and psychosocial stressors (mental stress).
A US study found that acute and sudden computer-related injuries, a separate category to injuries that take a while to emerge like repetitive strain injury, are rising rapidly in the US, and that young children are most affected.
Many health care professionals refer to RSI as ULD (upper limb disorder) because it frequently involves the forearm, elbow, wrist or hands. RSI often affects the neck as well.
The following are examples of repetitive strain injuries:
Bursitis - happens when the bursa is inflamed. The bursa acts as a cushion between bones, tendons, joints and muscles - bursae are fluid-filled sacs (the plural of bursa is bursae). People with bursitis will feel pain at the site of inflammation.
Carpal tunnel syndrome (CTS) - caused by the compression of the median nerve through the carpal tunnel in the wrist area. When constricted, blood cannot flow freely through the hand to the fingers causing individuals with CTS to experience numbness and pain in the hand.
Diffuse RSI - conditions are where the patient complains of pain and yet, on examination by a health care professional, nothing physical can be found to be wrong.
Dupuytren's contracture - a condition that affects the hands and fingers. It is an uncommon hand deformity in which the connective tissue under the skin of the palm contract and toughen over time. It causes one or more of the fingers on one or both hands to bend into the palm of the hand.
Epicondylitis - often occurs as a result of strenuous overuse of the muscles and tendons where the bone and tendon join. Tennis elbow and golfer's elbow are examples.
Ganglion - fluid-filled swellings that tend to form on top of joints or tendons in the wrists, hands, and feet. They have the appearance of firm or spongy sacs of liquid and their insides consist of a sticky, clear, thick, jelly-like fluid.
Rotator cuff syndrome - inflammation of tendons and muscles in the shoulder.
Tendinitis - also known as tendonitis, is the inflammation of a tendon.
Tenosynovitis - the sheath around the tendon becomes inflamed, specifically the inner lining of the tendon sheath.
Trigger finger - a condition in which one of your fingers or your thumb catches in a bent position. The tendon sheaths of the fingers or thumb become inflamed - the tendon is also inflamed.
RSI is frequently caused by such activities as golf or tennis - activities which require repetitive movements. Signs and symptoms generally persist if left untreated. Experts say that the number of people experiencing RSI as a result of computer use has been increasing for many years. RSI that is caused by typing on a computer keyboard is often referred to as writer's cramp.
Experts often refer to two main types of RSI:
Type 1 RSI - usually caused by repetitive tasks, but not always; some people who do not perform repetitive tasks may have Type 1 RSI. The muscles and tendons swell. Examples of Type 1 RSI include:
Carpal tunnel syndrome
Tendinitis (tendonitis)
Tenosynovitis
Type 2 RSI - there is a feeling of pain but no obvious inflammation or swelling in the area where symptoms are felt. The National Health Service (NHS), UK, refers to Type 2 RSI "when a person's symptoms do not fit into one of the (above listed) conditions". Also called non-specific pain syndrome.
What are the signs and symptoms of repetitive strain injury (RSI)?
A symptom is something the patient feels and reports, while a sign is something other people, such as the doctor detect. For example, pain may be a symptom while a rash may be a sign.
Signs and symptoms vary, depending on which part of the body is affected, and what caused the problem in the first place. Initially, symptoms may only occur when the individual is doing the repetitive task - they will slowly go away when the person rests. Eventually, though, symptoms may be present all the time (and worsen during the repetitive task) if left untreated.
The most common RSI signs and symptoms include:
Tenderness in the affected muscle or joint
Pain in the affected muscle or joint
A throbbing (pulsating) sensation in the affected area
Pins and needles (tingling) in the affected area, especially the hand or arm
Loss of sensation in the hand
Loss of strength in the hand
Some patients with persistent symptoms may have sleeping problems - the condition is often irreversible at this stage. Early treatment is much more likely to prevent any irreversible damage.
What are the causes of repetitive strain injury (RSI)?
Experts say the causes of RSI are a bit of a mystery. Sometimes there is no swelling in the muscles or tendons, but the patient feels pain and discomfort. We know that often repetitive movements of a part of the body are linked to symptoms - movements, such as typing, using a computer mouse, poor posture while doing a movement, using excessive force, doing the repetitive movements without sufficient breaks, etc. But the precise reason for RSI is not clear. Neither do we know why some people develop RSI and others don't, when doing the same tasks for similar periods.
Some studies indicate that some psycho-social workplace factors, such as stress may be significant contributory factors to RSI. Perhaps stress affects our muscles (makes them tense), which in turn makes us more sensitive to pain.
The following are seen as causes of RSI:
The overuse of muscles in our hands, wrists, arms, shoulders, neck and back are linked to RSI symptoms.
The area is affected by repeated actions, which are usually performed on a daily basis over a long period.
The repetitive actions are done in a cold place.
The individual has to use vibrating equipment.
Forceful movements are involved.
Workstations are poorly organized.
Equipment is badly designed.
The individual commonly adopts an awkward posture.
There are not enough rest breaks.
How is repetitive strain injury (RSI) diagnosed?
There is no objective way to diagnose RSI - there are no tests to confirm a diagnosis. Signs and symptoms could be caused by a wide range of factors.
A health care professional will usually diagnose RSI if the signs and symptoms can be linked to a specific repetitive task, and the symptoms lessen when the task is stopped.
If the patient develops a definable condition, such as frozen shoulder, carpal tunnel syndrome or tendinitis, it may or may not be linked to repetitive tasks.
What are the treatment options for repetitive strain injury (RSI)?
The National Health Service (NHS), UK, advises people to see their doctor as soon as they experience symptoms. Early treatment is more likely to result in effective outcomes.
A GP (general practitioner, primary care physician) will probably ask the patient to stop doing the repetitive movements which may be causing the symptoms. If this is not possible, as may be the case with work-related activities, the individual needs to tell his/her employer.
The aim of treatment is to help ease the pain, and to enable the patient to gain strength and mobility in the affected area.
Pain relief - a course of anti-inflammatory painkillers, such as ibuprofen or aspirin may help. Children under 16 years of age should not take aspirin. The following may also help:
Use of heat (applying heat to the affected area)
Cold packs
Elastic supports
Firm splints
Steroid injections - these may be administered if there is a well defined inflammation in the affected area.
Sleep - if the patient is having sleeping problems the doctor may prescribe a short course of sleeping tablets. Good sleep may help relax the patient and alter his/her perception and susceptibility to pain.
Physical therapy (UK: physiotherapy), exercise and relaxation techniques - a physical therapist (UK: physiotherapist) may help the patient adopt proper posture, as well as teaching him/her to strengthen muscles. Electrotherapy may also be used - small electrical impulses are placed at specific points of the body to help reduce pain. The following may also provide benefits:
Walking
Swimming
A Danish study found that five exercises reduced neck pain for women office workers.
Yoga
Tai chi
Mediation and relaxation techniques
Some say the "Alexander Technique" helps
Scientists at the University of British Columbia, Canada, found that "physical activity is associated with a lower risk of work-related repetitive strain injury".
Occupational Therapy - by analyzing the following factors with the help of an occupational therapist, there may be ways of adopting measures to reduce symptoms:
Working with a computer - is your equipment positioned properly. Are your seat, keyboard and mouse positioned in the best way to minimize strain on your hands, fingers, arms, back and neck. Adaptive technology, such as special keyboards, mouse replacements, pen tablets interfaces, and speech recognition software may help.
Posture - are you sitting correctly?
Breaks - when doing repetitive tasks are you getting enough breaks? There is software that reminds computer users it is time to have a break.
Work environment - is there anything your employer might do to improve your working environment?
Stress - is there anything you can do to alleviate (treat) your level of stress?
Many patients experience reduced symptoms, or total elimination of symptoms if prevention and treatment measures are carried out. Others, however, continue to suffer regardless. Unfortunately, there are cases of people having to leave/change their jobs.
Written by
воскресенье, 24 апреля 2011 г.
Impacts Of Climate Change On Wheat In England And Wales
Extreme weather events are likely to increase with global warming. However, it is not clear how this might affect agricultural crops and whether yield losses from drought or heat stress will increase in future.
Using crop simulation models combined with climate scenarios, it was demonstrated that despite higher temperature and lower summer precipitation predicted in the UK for the 2050s, the impact of drought stress on wheat yield is likely to decrease, because wheat will mature earlier avoiding severe drought.
However, the probability of heat stress around flowering resulting in considerable yield losses may increase significantly.
Breeding strategies might need to focus on wheat varieties tolerant to high temperature, rather than to drought.
Journal of the Royal Society Interface
Journal of the Royal Society Interface is the Society's cross-disciplinary publication promoting research at the interface between the physical and life sciences. It offers rapidity, visibility and high-quality peer review and is ranked fifth in JCR's multidisciplinary category. The journal also incorporates Interface Focus, a peer-reviewed, themed supplement, each issue of which concentrates on a specific cross-disciplinary subject.
Journal of the Royal Society Interface
Using crop simulation models combined with climate scenarios, it was demonstrated that despite higher temperature and lower summer precipitation predicted in the UK for the 2050s, the impact of drought stress on wheat yield is likely to decrease, because wheat will mature earlier avoiding severe drought.
However, the probability of heat stress around flowering resulting in considerable yield losses may increase significantly.
Breeding strategies might need to focus on wheat varieties tolerant to high temperature, rather than to drought.
Journal of the Royal Society Interface
Journal of the Royal Society Interface is the Society's cross-disciplinary publication promoting research at the interface between the physical and life sciences. It offers rapidity, visibility and high-quality peer review and is ranked fifth in JCR's multidisciplinary category. The journal also incorporates Interface Focus, a peer-reviewed, themed supplement, each issue of which concentrates on a specific cross-disciplinary subject.
Journal of the Royal Society Interface
First All-African GM Crop Is Resistant To Maize Streak Virus
The first all-African genetically modified crop plant with resistance to the severe maize streak virus (MSV), which seriously reduces the continent's maize yield, has been developed by scientists from the University of Cape Town and PANNAR PTY Ltd, a South African seed company. The research, published in Plant Biotechnology Journal represents a significant advance in African agricultural biotechnology, and will play an important role in alleviating Africa's food shortages and famine.
Dr Dionne Shepherd, lead researcher explains, "MSV is transmitted to maize by small insects called leafhoppers. The disease is therefore a result of a complex interplay between the plant, the virus and insect. Factors that can influence the severity of the disease include the age at which the plant is infected (the younger the plant, the more severe the infection), the maize variety (some are more susceptible than others), and environmental conditions.
"We have created an MSV-resistant maize variety by genetic engineering, using an approach known as pathogen-derived resistance. This means that a gene from the viral pathogen is used to protect the plant from that pathogen. We mutated a viral gene that under normal circumstances produces a protein that is essential for the virus to replicate itself and inserted it into the maize plant's genome, creating genetically modified maize. When the virus infects one of these transgenic maize plants, it displays a significant delay in symptom development, a decrease in symptom severity and higher survival rates than non-transgenic plants."
The next stage of the research involves field trials to ensure that the transformed crop is digestible, that the protein is not an allergen and that it will be ecologically friendly to other organisms within the environment. Following the results of these trials, the crop will be monitored over a number of growing seasons before it is made accessible to local farmers.
BLACKWELL PUBLISHING LTD
9600 Garsington Road
Oxford OX4 2DQ
blackwellpublishing
Dr Dionne Shepherd, lead researcher explains, "MSV is transmitted to maize by small insects called leafhoppers. The disease is therefore a result of a complex interplay between the plant, the virus and insect. Factors that can influence the severity of the disease include the age at which the plant is infected (the younger the plant, the more severe the infection), the maize variety (some are more susceptible than others), and environmental conditions.
"We have created an MSV-resistant maize variety by genetic engineering, using an approach known as pathogen-derived resistance. This means that a gene from the viral pathogen is used to protect the plant from that pathogen. We mutated a viral gene that under normal circumstances produces a protein that is essential for the virus to replicate itself and inserted it into the maize plant's genome, creating genetically modified maize. When the virus infects one of these transgenic maize plants, it displays a significant delay in symptom development, a decrease in symptom severity and higher survival rates than non-transgenic plants."
The next stage of the research involves field trials to ensure that the transformed crop is digestible, that the protein is not an allergen and that it will be ecologically friendly to other organisms within the environment. Following the results of these trials, the crop will be monitored over a number of growing seasons before it is made accessible to local farmers.
BLACKWELL PUBLISHING LTD
9600 Garsington Road
Oxford OX4 2DQ
blackwellpublishing
Study Reveals How Molecules Inhibit Growth Of Lung Cancer Cells
By mapping the interlocking structures of small molecules and mutated protein "receptors" in non small cell lung cancer (NSCLC) cells, scientists at Dana-Farber Cancer Institute and their colleagues have energized efforts to design molecules that mesh with these receptors, potentially interfering with cancer cell growth and survival.
In a study published in the March issue of Cancer Cell, researchers led by Michael Eck, MD, PhD, of Dana-Farber used X-ray crystallography to determine the structure of two mutated forms of the epidermal growth factor receptor (EGFR) in lung cancer cells. EGFR, a protein known as a tyrosine kinase, plays a key role in relaying growth signals within cells. When mutated, it can become overactive, leading to excessive cell division and cancer.
"It turns out that in some cases, the very mutation that causes the cancer in the first place is also the cancer's Achilles' heel," said Eck, the paper's senior author. "We now see that inhibitors such as gefitinib actually bind more tightly to some of the cancer-causing mutants, even though they were originally developed to block the normal receptor."
Cai-Hong Yun, PhD, of Dana-Farber is the paper's first author.
Mutations in the EGFR kinase domain occur in approximately 16 percent of NSCLCs, but at much higher frequencies in selected populations, including nonsmokers, women, and East Asian patients. Laboratory and clinical studies have shown that tyrosine kinase inhibitors are more effective against some EGFR mutations than others, although the molecular reasons for this are unclear. By developing a better understanding of the effect of the mutations on inhibitor binding at a structural level, it may be possible to develop more effective therapies.
In the current study, Eck and his colleagues analyzed the three-dimensional structures of the normal and mutated versions of EGFR bound to several different types of inhibitor molecules. They found that two inhibitors the drug gefitinib (marketed as Iressa(R), and a compound called AEE788 bind especially tightly to one of the mutated forms, meaning these inhibitors are potentially more effective at blocking the growth of cancer cells containing that mutation. In the case of gefitinib, it bound 20 times more tightly to the L858R mutant than to the normal, mutation-free EGFR.
The research team concluded that the particular EGFR mutation within tumor cells determines which inhibitor molecules are likely to be able to slow or stop the growth of those cells.
"Although structural divergence in the EGFR mutants may complicate efforts to treat the disease, it may also present an advantage in that it introduces the possibility of developing inhibitors that target specific mutations, which should lead to more effective treatments," said Eck, who also an associate professor of Biological Chemistry and Molecular Pharmacology at Harvard Medical School. "These targeted therapies likely would be less toxic as they, in theory, would not affect the normal functioning EGFR proteins."
In addition to Eck and Yun, the paper's other authors are Titus Boggon, PhD, formerly of Dana-Farber and now at Yale University School of Medicine; Yiqun Li and Michele Woo of Dana-Farber; and Heidi Greulich, PhD, and Matthew Meyerson, MD, PhD, of Dana-Farber and the Broad Institute of Harvard and Massachusetts Institute of Technology.
The research was supported with grants from the National Institutes of Health, the Leukemia and Lymphoma Society, and American Society of Hematology.
Dana-Farber Cancer Institute (dana-farber) is a principal teaching affiliate of the Harvard Medical School and is among the leading cancer research and care centers in the United States. It is a founding member of the Dana-Farber/Harvard Cancer Center (DF/HCC), designated a comprehensive cancer center by the National Cancer Institute.
Dana-Farber Cancer Institute
44 Binney St., OS 382 A
Boston, MA 02215
United States
dana-farber/
In a study published in the March issue of Cancer Cell, researchers led by Michael Eck, MD, PhD, of Dana-Farber used X-ray crystallography to determine the structure of two mutated forms of the epidermal growth factor receptor (EGFR) in lung cancer cells. EGFR, a protein known as a tyrosine kinase, plays a key role in relaying growth signals within cells. When mutated, it can become overactive, leading to excessive cell division and cancer.
"It turns out that in some cases, the very mutation that causes the cancer in the first place is also the cancer's Achilles' heel," said Eck, the paper's senior author. "We now see that inhibitors such as gefitinib actually bind more tightly to some of the cancer-causing mutants, even though they were originally developed to block the normal receptor."
Cai-Hong Yun, PhD, of Dana-Farber is the paper's first author.
Mutations in the EGFR kinase domain occur in approximately 16 percent of NSCLCs, but at much higher frequencies in selected populations, including nonsmokers, women, and East Asian patients. Laboratory and clinical studies have shown that tyrosine kinase inhibitors are more effective against some EGFR mutations than others, although the molecular reasons for this are unclear. By developing a better understanding of the effect of the mutations on inhibitor binding at a structural level, it may be possible to develop more effective therapies.
In the current study, Eck and his colleagues analyzed the three-dimensional structures of the normal and mutated versions of EGFR bound to several different types of inhibitor molecules. They found that two inhibitors the drug gefitinib (marketed as Iressa(R), and a compound called AEE788 bind especially tightly to one of the mutated forms, meaning these inhibitors are potentially more effective at blocking the growth of cancer cells containing that mutation. In the case of gefitinib, it bound 20 times more tightly to the L858R mutant than to the normal, mutation-free EGFR.
The research team concluded that the particular EGFR mutation within tumor cells determines which inhibitor molecules are likely to be able to slow or stop the growth of those cells.
"Although structural divergence in the EGFR mutants may complicate efforts to treat the disease, it may also present an advantage in that it introduces the possibility of developing inhibitors that target specific mutations, which should lead to more effective treatments," said Eck, who also an associate professor of Biological Chemistry and Molecular Pharmacology at Harvard Medical School. "These targeted therapies likely would be less toxic as they, in theory, would not affect the normal functioning EGFR proteins."
In addition to Eck and Yun, the paper's other authors are Titus Boggon, PhD, formerly of Dana-Farber and now at Yale University School of Medicine; Yiqun Li and Michele Woo of Dana-Farber; and Heidi Greulich, PhD, and Matthew Meyerson, MD, PhD, of Dana-Farber and the Broad Institute of Harvard and Massachusetts Institute of Technology.
The research was supported with grants from the National Institutes of Health, the Leukemia and Lymphoma Society, and American Society of Hematology.
Dana-Farber Cancer Institute (dana-farber) is a principal teaching affiliate of the Harvard Medical School and is among the leading cancer research and care centers in the United States. It is a founding member of the Dana-Farber/Harvard Cancer Center (DF/HCC), designated a comprehensive cancer center by the National Cancer Institute.
Dana-Farber Cancer Institute
44 Binney St., OS 382 A
Boston, MA 02215
United States
dana-farber/
Abnormal Expression Of Differentiation Related Proteins And Proteoglycan Core Proteins In The Urothelium Of Patients With Interstitial Cystitis
- Daniel Culkin, MD, Chair of Urology and lead clinical researcher teamed with Robert Hurst, PhD to investigate changes in the bladder urothelium that lead to the loss of impermeability. For an earlier paper1 a set of shallow cold-cup biopsies was collected under very rigidly controlled conditions from patients who all experienced moderate to severe symptoms. The paper demonstrated multiple abnormalities in E-cadherin, ZO-1, and uroplakin, the glycosaminoglycan chondroitin sulfate and the morphology and cellular polarity of the urothelium. The current study aimed at digging deeper into the expression of molecules involved with differentiation and the so-called GAG layer and therefore analyzed expression of proteoglycan core proteins to determine the cause of the loss of chondroitin sulfate seen in IC-derived biopsies and cytokeratins to further define the change in the differentiation program. The current data were analyzed together with the earlier data using clustering algorithms to identify natural groupings among the data.
Our initial clustering analysis as originally submitted showed that the markers fell naturally into three major groups: all the proteoglycan core proteins and the tight junction protein, ZO-1; differentiation-related markers including the cytokeratins, uroplakin, and the morphology-polarity score, and a single protein, E-cadherin, which was overexpressed in IC. Susan Keay, MD, reported earlier that the mRNA of E-cadherin also was overexpressed in the urothelium of IC patients2. The samples themselves fell naturally into 4 groups. All the normals clustered together and were distinct from the patient samples. One group consisted of biopsies in which most of the findings were abnormal. A second group was similar, but not quite so severe. A third group consisted of samples in which the predominant finding was abnormal E-cadherin with most of the other markers showing a normal or near normal distribution. Due to the suggestion of a perceptive reviewer, we added an assessment of inflammation in the specimens by Barbara Bane, MD, our uropathologist. This led to the important finding that inflammation correlated very poorly with any of the other markers, indicating that inflammation could not be the cause of the altered differentiation seen in the urothelium of IC patients. This paper shows both qualitative and quantitative changes in the expression of GAG layer and tight junction proteins ("defenses molecules") and differentiation proteins can be defined in IC and perhaps used both to understand the pathophysiology of the IC in relation to the wider problem of chronic pelvic pain.
References
1. Slobodov G, Feloney M, Gran C, Kyker KD, Hurst RE, and Culkin DJ . Abnormal Expression of Molecular Markers for Bladder Impermeability and Differentiation in Urothelium of Interstitial Cystitis Patients. J Urol 2004;171:1554-1558.
2. Keay S, Seillier-Moiseiwitsch F, Zhang CO, Chai T, and Zhang J . Changes in human bladder epithelial cell gene expression associated with interstitial cystitis or antiproliferative factor treatment. Physiol Genomics 2003;14:107-115.
Written by
Robert E. Hurst, PhD, as part of Beyond the Abstract on . This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Link to Full Abstract
- the only urology website with original content written by global urology key opinion leaders actively engaged in clinical practice.
To access the latest urology news releases from , go to:
----------------------------
Copyright © 2007 -
.
----------------------------
Our initial clustering analysis as originally submitted showed that the markers fell naturally into three major groups: all the proteoglycan core proteins and the tight junction protein, ZO-1; differentiation-related markers including the cytokeratins, uroplakin, and the morphology-polarity score, and a single protein, E-cadherin, which was overexpressed in IC. Susan Keay, MD, reported earlier that the mRNA of E-cadherin also was overexpressed in the urothelium of IC patients2. The samples themselves fell naturally into 4 groups. All the normals clustered together and were distinct from the patient samples. One group consisted of biopsies in which most of the findings were abnormal. A second group was similar, but not quite so severe. A third group consisted of samples in which the predominant finding was abnormal E-cadherin with most of the other markers showing a normal or near normal distribution. Due to the suggestion of a perceptive reviewer, we added an assessment of inflammation in the specimens by Barbara Bane, MD, our uropathologist. This led to the important finding that inflammation correlated very poorly with any of the other markers, indicating that inflammation could not be the cause of the altered differentiation seen in the urothelium of IC patients. This paper shows both qualitative and quantitative changes in the expression of GAG layer and tight junction proteins ("defenses molecules") and differentiation proteins can be defined in IC and perhaps used both to understand the pathophysiology of the IC in relation to the wider problem of chronic pelvic pain.
References
1. Slobodov G, Feloney M, Gran C, Kyker KD, Hurst RE, and Culkin DJ . Abnormal Expression of Molecular Markers for Bladder Impermeability and Differentiation in Urothelium of Interstitial Cystitis Patients. J Urol 2004;171:1554-1558.
2. Keay S, Seillier-Moiseiwitsch F, Zhang CO, Chai T, and Zhang J . Changes in human bladder epithelial cell gene expression associated with interstitial cystitis or antiproliferative factor treatment. Physiol Genomics 2003;14:107-115.
Written by
Robert E. Hurst, PhD, as part of Beyond the Abstract on . This initiative offers a method of publishing for the professional urology community. Authors are given an opportunity to expand on the circumstances, limitations etc... of their research by referencing the published abstract.
Link to Full Abstract
- the only urology website with original content written by global urology key opinion leaders actively engaged in clinical practice.
To access the latest urology news releases from , go to:
----------------------------
Copyright © 2007 -
.
----------------------------
Fewer, Smaller Skin Cancer Tumors After Blocking Protein
New research suggests that blocking the activity of a protein in the blood could offer powerful protection against some skin cancers.
In the study, normal mice and mice that had a genetically engineered protein deficiency were exposed to almost a year of ultraviolet light that mimics chronic sun exposure. The mice that lacked the protein developed fewer, smaller, less aggressive and less vascular skin cancer tumors than did the normal mice.
Because a low-dose drug that blocks the protein's activity in the blood is currently under investigation by a Pennsylvania pharmaceutical company, the researchers hope that someday, a simple pill might help prevent or treat nonmelanoma skin cancer in people at highest risk for the disease.
More than 1 million cases of nonmelanoma skin cancer are diagnosed in the United States each year, according to the National Cancer Institute. The two most common types are basal cell carcinoma, which forms in small cells in the base of the outer layer of skin, and squamous cell carcinoma, which forms in cells that compose the surface of the skin.
The protein is called macrophage migration inhibitory factor, or MIF. It is a pro-inflammatory cytokine present in human blood that generates inflammation in response to infection, offering protection against some pathogens. But in this research, MIF emerged as a contributor to the chronic inflammation that precedes the development of skin cancer after long-term sun exposure. Previous studies have implicated MIF in other cancers, as well.
"Our data show that MIF appears to be affecting multiple pathways that are important for tumor generation and progression. It also is clear here that there is a link between inflammation and cancer," said Abhay Satoskar, associate professor of microbiology at Ohio State University and a coauthor of the study.
"No one else has shown this in a skin cancer model."
The study is scheduled for publication in the March 2009 issue of the Journal of the Federation of American Societies for Experimental Biology.
The scientists exposed normal mice and mice deficient in MIF to ultraviolet B light, the type of radiation from the sun that damages the skin. The mice were exposed to the light three days per week for 46 weeks, with doses increased regularly after week 13 to account for skin adaption to UVB exposure. The exposure in the study was designed to accelerate tumor growth and far exceeded the UVB exposure that humans experience over the same time period.
By week 37, more than two-thirds of the mice exposed to UVB light had developed at least one tumor, and all mice had developed tumors by week 45. The MIF-deficient mice averaged 2.89 tumors per mouse at the end of the exposure, compared to an average of 5.27 tumors per normal mouse. Overall, the MIF-deficient mice on average had about half as many tumors and significantly smaller tumors than did the normal mice. The tumors on the MIF-deficient mice were also less likely to be malignant than were tumors on normal mice.
Satoskar and colleagues compared a number of tumor characteristics on the two groups of UVB-exposed mice to confirm the MIF deficiency's role in lowering the incidence of skin cancer.
The MIF-deficient mice had almost twice as many tumor-suppressor cells of the p53 gene than did normal mice, suggesting that the presence of the MIF protein interferes with this tumor suppressor's ability to do its work. The MIF-deficient mice also had lower concentrations of the protein vascular endothelial growth factor (VEGF) than did normal mice. VEGF has previously been found to promote the development of blood vessels in certain types of cancer tumors, so the lower amount of the protein in MIF-deficient mice means the tumors they did develop had less vascular support to grow, Satoskar said.
Finally, MIF-deficient mice exposed to UVB rays had lower levels of three markers for inflammation, indicating an important link between MIF and the inflammatory response in skin that follows UVB exposure.
The scientists also observed that the MIF deficiency did not cause any significant side effects in the mice. Under normal circumstances, the amount of MIF in the blood remains constant.
"Some MIF is not bad, but we think that if it goes above a certain threshold, it starts doing crazy things," Satoskar said. "We're not aware of the natural existence of a MIF deficiency in humans, but in a mouse, we don't see any toxic effects."
MIF is also an important target for skin cancer research because previous studies have identified five polymorphisms in the MIF gene in humans. Polymorphisms are mutations in genes that, in the case of MIF, might make some individuals produce higher or lower levels of the protein, which could influence their susceptibility to skin cancers.
Satoskar and colleagues plan to examine biopsies of patients who have been diagnosed with squamous cell or basal cell carcinoma to see if these patients have a polymorphism on the MIF gene that would suggest a genetic predisposition toward the cancer.
"If we find a correlation, a MIF-gene polymorphism could become a biomarker to predict skin cancer. That would mean people who have a polymorphism that makes them high MIF producers would be more likely to develop skin cancer if they are exposed to the sun," Satoskar said. "We don't know yet whether there is a correlation, however."
The researchers also plan to begin tests of the drug under development in their MIF-deficient mouse model. The drug is based on a small molecule that blocks the activity of MIF in the blood and has been effective in other animal models of inflammatory diseases at a very low dose.
"Our goal is to move forward to see whether this molecule is a new target for prevention and/or treatment of this disease," Satoskar said.
This work was supported by an Ohio State University Comprehensive Cancer Center seed grant.
Co-authors on the study are Jason Martin, Jason Duncan, Samuel Shin and Anne VanBuskirk (formerly) of the Department of Surgery; Tracy Keiser of the Department of Microbiology; Donna Kusewitt of the Department of Veterinary Biosciences; and Tatiana Oberyszyn of the Department of Pathology, all at Ohio State. VanBuskirk also had appointments in pathology and the Comprehensive Cancer Center; she is now with Takeda Pharmaceuticals North America.
Written by Emily Caldwell
Source: Abhay Satoskar
Ohio State University
In the study, normal mice and mice that had a genetically engineered protein deficiency were exposed to almost a year of ultraviolet light that mimics chronic sun exposure. The mice that lacked the protein developed fewer, smaller, less aggressive and less vascular skin cancer tumors than did the normal mice.
Because a low-dose drug that blocks the protein's activity in the blood is currently under investigation by a Pennsylvania pharmaceutical company, the researchers hope that someday, a simple pill might help prevent or treat nonmelanoma skin cancer in people at highest risk for the disease.
More than 1 million cases of nonmelanoma skin cancer are diagnosed in the United States each year, according to the National Cancer Institute. The two most common types are basal cell carcinoma, which forms in small cells in the base of the outer layer of skin, and squamous cell carcinoma, which forms in cells that compose the surface of the skin.
The protein is called macrophage migration inhibitory factor, or MIF. It is a pro-inflammatory cytokine present in human blood that generates inflammation in response to infection, offering protection against some pathogens. But in this research, MIF emerged as a contributor to the chronic inflammation that precedes the development of skin cancer after long-term sun exposure. Previous studies have implicated MIF in other cancers, as well.
"Our data show that MIF appears to be affecting multiple pathways that are important for tumor generation and progression. It also is clear here that there is a link between inflammation and cancer," said Abhay Satoskar, associate professor of microbiology at Ohio State University and a coauthor of the study.
"No one else has shown this in a skin cancer model."
The study is scheduled for publication in the March 2009 issue of the Journal of the Federation of American Societies for Experimental Biology.
The scientists exposed normal mice and mice deficient in MIF to ultraviolet B light, the type of radiation from the sun that damages the skin. The mice were exposed to the light three days per week for 46 weeks, with doses increased regularly after week 13 to account for skin adaption to UVB exposure. The exposure in the study was designed to accelerate tumor growth and far exceeded the UVB exposure that humans experience over the same time period.
By week 37, more than two-thirds of the mice exposed to UVB light had developed at least one tumor, and all mice had developed tumors by week 45. The MIF-deficient mice averaged 2.89 tumors per mouse at the end of the exposure, compared to an average of 5.27 tumors per normal mouse. Overall, the MIF-deficient mice on average had about half as many tumors and significantly smaller tumors than did the normal mice. The tumors on the MIF-deficient mice were also less likely to be malignant than were tumors on normal mice.
Satoskar and colleagues compared a number of tumor characteristics on the two groups of UVB-exposed mice to confirm the MIF deficiency's role in lowering the incidence of skin cancer.
The MIF-deficient mice had almost twice as many tumor-suppressor cells of the p53 gene than did normal mice, suggesting that the presence of the MIF protein interferes with this tumor suppressor's ability to do its work. The MIF-deficient mice also had lower concentrations of the protein vascular endothelial growth factor (VEGF) than did normal mice. VEGF has previously been found to promote the development of blood vessels in certain types of cancer tumors, so the lower amount of the protein in MIF-deficient mice means the tumors they did develop had less vascular support to grow, Satoskar said.
Finally, MIF-deficient mice exposed to UVB rays had lower levels of three markers for inflammation, indicating an important link between MIF and the inflammatory response in skin that follows UVB exposure.
The scientists also observed that the MIF deficiency did not cause any significant side effects in the mice. Under normal circumstances, the amount of MIF in the blood remains constant.
"Some MIF is not bad, but we think that if it goes above a certain threshold, it starts doing crazy things," Satoskar said. "We're not aware of the natural existence of a MIF deficiency in humans, but in a mouse, we don't see any toxic effects."
MIF is also an important target for skin cancer research because previous studies have identified five polymorphisms in the MIF gene in humans. Polymorphisms are mutations in genes that, in the case of MIF, might make some individuals produce higher or lower levels of the protein, which could influence their susceptibility to skin cancers.
Satoskar and colleagues plan to examine biopsies of patients who have been diagnosed with squamous cell or basal cell carcinoma to see if these patients have a polymorphism on the MIF gene that would suggest a genetic predisposition toward the cancer.
"If we find a correlation, a MIF-gene polymorphism could become a biomarker to predict skin cancer. That would mean people who have a polymorphism that makes them high MIF producers would be more likely to develop skin cancer if they are exposed to the sun," Satoskar said. "We don't know yet whether there is a correlation, however."
The researchers also plan to begin tests of the drug under development in their MIF-deficient mouse model. The drug is based on a small molecule that blocks the activity of MIF in the blood and has been effective in other animal models of inflammatory diseases at a very low dose.
"Our goal is to move forward to see whether this molecule is a new target for prevention and/or treatment of this disease," Satoskar said.
This work was supported by an Ohio State University Comprehensive Cancer Center seed grant.
Co-authors on the study are Jason Martin, Jason Duncan, Samuel Shin and Anne VanBuskirk (formerly) of the Department of Surgery; Tracy Keiser of the Department of Microbiology; Donna Kusewitt of the Department of Veterinary Biosciences; and Tatiana Oberyszyn of the Department of Pathology, all at Ohio State. VanBuskirk also had appointments in pathology and the Comprehensive Cancer Center; she is now with Takeda Pharmaceuticals North America.
Written by Emily Caldwell
Source: Abhay Satoskar
Ohio State University
Molecule By Molecule, New Assay Shows Real-time Gene Activity
CAMBRIDGE, Mass. -- Chemists at Harvard University have developed the first technique providing a real-time, molecule-by-molecule "movie" of protein production in live cells. Their direct observation of fluorescently tagged molecules in single cells -- providing striking real-time footage of the birth of individual new protein molecules inside -- greatly increases scientists' precision in probing genetic activity.
Using the new assay, described this week in the journal Science, researchers led by Harvard's X. Sunney Xie counted, one by one, protein molecules generated in small bursts within cells as multiple ribosomes bound to single copies of mRNA complete the process by which DNA, an organism's long-term genetic repository, yields its crop of proteins. These random, or stochastic, bursts of protein expression are described in detail in a separate paper Xie and colleagues present this week in Nature.
"Although central to life processes, the expression of many important genes takes place at very low levels, making it difficult or impossible to observe using current technologies," says Xie, professor of chemistry and chemical biology in Harvard's Faculty of Arts and Sciences. "Our experiments provide the most sensitive means to date of observing real-time activity of single molecules inside cells. This new technique could provide us with unprecedented insights into gene expression and many other fundamental biological processes in living cells." The central dogma of molecular biology holds that DNA is transcribed into mRNA, which is then translated into proteins. But several technical hurdles have hampered study of these key processes. Researchers' current understanding of this two-step pathway is built upon their averaging of genetic and biochemical activity across large populations of cells and molecules, masking the essential randomness of the process at the cellular level. Furthermore, much of our knowledge on the workings of the molecular machinery involved in gene expression comes from experiments done in vitro, rather than in living cells. Finally, the low sensitivity of current techniques for detecting gene expression has restricted analysis to highly expressed genes.
Xie's new assay addresses all three limitations. He and his colleagues melded a yellow fluorescent protein called Venus with Tsr, a hydrophobic membrane protein. The inclusion of the Tsr domain serves to anchor the fused protein to a cell's membrane, sidestepping the longstanding difficulty of imaging single proteins zipping about in cell cytoplasm, where diffuse fluorescent signals tend to be overwhelmed by background noise.
The gene coding for this combined protein was substituted for the well-studied lacZ gene in the Escherichia coli chromosome. When lacZ's regulatory machinery allows the modified gene to be converted into a handful of protein molecules, these Tsr-Venus hybrids migrate to the cell membrane, where each attaches firmly. The clearly visible flash from each Tsr-Venus molecule -- which when viewed across a population of cells looks somewhat akin to a sea of cellular paparazzi -- serves as an indication of that single protein molecule's production.
"Dr. Xie's experiments are the first to obtain quantitative, real-time information on protein expression in living cells at the single-molecule level," says Jeremy M. Berg, director of the National Institute of General Medical Sciences, which funded the work in part. "His imaging methods open up new possibilities for addressing fundamental questions about the precise events and factors involved in regulating these essential processes. This is exactly the sort of highly innovative research with broad applicability that the National Institutes of Health Director's Pioneer Award was created to support."
Xie's Science co-authors are Ji Yu, Jie Xiao, and Xiaojia Ren at Harvard and Kaiqin Lao of Applied Biosystems. His Nature co-authors are Long Cai and Nir Friedman at Harvard. The work was funded by the NIH's Director's Pioneer Award, the U.S. Department of Energy's Office of Science's Genomics: GtL program, Applied Biosystems, and Merck.
Contact: Steve Bradt
steve_bradtharvard
Harvard University
Using the new assay, described this week in the journal Science, researchers led by Harvard's X. Sunney Xie counted, one by one, protein molecules generated in small bursts within cells as multiple ribosomes bound to single copies of mRNA complete the process by which DNA, an organism's long-term genetic repository, yields its crop of proteins. These random, or stochastic, bursts of protein expression are described in detail in a separate paper Xie and colleagues present this week in Nature.
"Although central to life processes, the expression of many important genes takes place at very low levels, making it difficult or impossible to observe using current technologies," says Xie, professor of chemistry and chemical biology in Harvard's Faculty of Arts and Sciences. "Our experiments provide the most sensitive means to date of observing real-time activity of single molecules inside cells. This new technique could provide us with unprecedented insights into gene expression and many other fundamental biological processes in living cells." The central dogma of molecular biology holds that DNA is transcribed into mRNA, which is then translated into proteins. But several technical hurdles have hampered study of these key processes. Researchers' current understanding of this two-step pathway is built upon their averaging of genetic and biochemical activity across large populations of cells and molecules, masking the essential randomness of the process at the cellular level. Furthermore, much of our knowledge on the workings of the molecular machinery involved in gene expression comes from experiments done in vitro, rather than in living cells. Finally, the low sensitivity of current techniques for detecting gene expression has restricted analysis to highly expressed genes.
Xie's new assay addresses all three limitations. He and his colleagues melded a yellow fluorescent protein called Venus with Tsr, a hydrophobic membrane protein. The inclusion of the Tsr domain serves to anchor the fused protein to a cell's membrane, sidestepping the longstanding difficulty of imaging single proteins zipping about in cell cytoplasm, where diffuse fluorescent signals tend to be overwhelmed by background noise.
The gene coding for this combined protein was substituted for the well-studied lacZ gene in the Escherichia coli chromosome. When lacZ's regulatory machinery allows the modified gene to be converted into a handful of protein molecules, these Tsr-Venus hybrids migrate to the cell membrane, where each attaches firmly. The clearly visible flash from each Tsr-Venus molecule -- which when viewed across a population of cells looks somewhat akin to a sea of cellular paparazzi -- serves as an indication of that single protein molecule's production.
"Dr. Xie's experiments are the first to obtain quantitative, real-time information on protein expression in living cells at the single-molecule level," says Jeremy M. Berg, director of the National Institute of General Medical Sciences, which funded the work in part. "His imaging methods open up new possibilities for addressing fundamental questions about the precise events and factors involved in regulating these essential processes. This is exactly the sort of highly innovative research with broad applicability that the National Institutes of Health Director's Pioneer Award was created to support."
Xie's Science co-authors are Ji Yu, Jie Xiao, and Xiaojia Ren at Harvard and Kaiqin Lao of Applied Biosystems. His Nature co-authors are Long Cai and Nir Friedman at Harvard. The work was funded by the NIH's Director's Pioneer Award, the U.S. Department of Energy's Office of Science's Genomics: GtL program, Applied Biosystems, and Merck.
Contact: Steve Bradt
steve_bradtharvard
Harvard University
Cedars-Sinai Researchers Present New Endocrine Findings At 2 International Conferences
Researchers in endocrinology at Cedars-Sinai Medical Center made several presentations at the annual meetings of The Endocrine Society (June 2-5, 2007) and the International Pituitary Congress (June 5-7, 2007).
At The Endocrine Society meeting, Shlomo Melmed, M.D., director of the Burns and Allen Research Institute at Cedars-Sinai Medical Center and one of the world's experts on human growth hormone and the pituitary gland, presented "The Year in Pituitary," an overview of new research in the field including innovative insights linking the pituitary gland to the understanding of systemic illness, mental disorders and the aging process, advances in subcellular mechanisms in the pathogenesis of pituitary disorders, and the publication of new data reflecting long term medical treatment outcomes in patients with acromegaly. Melmed, who is president and founding member of the Pituitary Society and president of the International Society of Endocrinology, also highlighted challenges scientists continue to face as they advance the diagnosis, treatment and understanding of endocrine disorders. (Plenary session)
The two other presentations by Cedars-Sinai researchers at The Endocrine Society meeting were:
*
Management of Acromegaly: Prolactinoma, Cushings and Acromegaly: an Update in Medical Therapy for Pituitary Ademomas - Ancillary Symposium
*
Bench to Bedside: Effects of Hormones on Breast Cancer, "Oct-1 Induces hPTTG1 Expression in Human Breast Cancer" - Poster Presentation
The following presentations were made by Cedars-Sinai researchers at the International Pituitary Congress:
*
Comparison of Endoscopic Endonasal and Microscopic Endonasal Surgery for Pituitary Adenoma - poster presentation
*
EGF Receptor - Mediated Control of Pituitary Tumor Growth and Hormone Secretion - poster presentation
*
Tumor Volume Analysis of Non-functioning Pituitary Adenoma Growth - poster presentation
*
Silent Corticotroph Adenomas: An Aggressive Clinico-Pathologic Entity Distinct From Non-Functioning Pituitary Tumors - poster presentation
*
Pttg (Pituitary tumor transforming gene) is Required for Pituitary Tumor Development in Rb+/- Mice by Preventing p21-dependent Senescence - poster presentation
*
Identification of Murine Pituitary Tumor Progenitor Cells - oral presentation
The first in Southern California and one of only 10 hospitals in the state whose nurses have been honored with the prestigious Magnet designation, Cedars-Sinai Medical Center is one of the largest nonprofit academic medical centers in the Western United States. For 19 consecutive years, it has been named Los Angeles' most preferred hospital for all health needs in an independent survey of area residents. Cedars-Sinai is internationally renowned for its diagnostic and treatment capabilities as well as breakthroughs in biomedical research and superlative medical education. It ranks among the top 10 non-university hospitals in the nation for its research activities and is fully accredited by the Association for the Accreditation of Human Research Protection Programs, Inc. (AAHRPP). Additional information is available at cedars-sinai/.
Contact: Simi Singer
Cedars-Sinai Medical Center
At The Endocrine Society meeting, Shlomo Melmed, M.D., director of the Burns and Allen Research Institute at Cedars-Sinai Medical Center and one of the world's experts on human growth hormone and the pituitary gland, presented "The Year in Pituitary," an overview of new research in the field including innovative insights linking the pituitary gland to the understanding of systemic illness, mental disorders and the aging process, advances in subcellular mechanisms in the pathogenesis of pituitary disorders, and the publication of new data reflecting long term medical treatment outcomes in patients with acromegaly. Melmed, who is president and founding member of the Pituitary Society and president of the International Society of Endocrinology, also highlighted challenges scientists continue to face as they advance the diagnosis, treatment and understanding of endocrine disorders. (Plenary session)
The two other presentations by Cedars-Sinai researchers at The Endocrine Society meeting were:
*
Management of Acromegaly: Prolactinoma, Cushings and Acromegaly: an Update in Medical Therapy for Pituitary Ademomas - Ancillary Symposium
*
Bench to Bedside: Effects of Hormones on Breast Cancer, "Oct-1 Induces hPTTG1 Expression in Human Breast Cancer" - Poster Presentation
The following presentations were made by Cedars-Sinai researchers at the International Pituitary Congress:
*
Comparison of Endoscopic Endonasal and Microscopic Endonasal Surgery for Pituitary Adenoma - poster presentation
*
EGF Receptor - Mediated Control of Pituitary Tumor Growth and Hormone Secretion - poster presentation
*
Tumor Volume Analysis of Non-functioning Pituitary Adenoma Growth - poster presentation
*
Silent Corticotroph Adenomas: An Aggressive Clinico-Pathologic Entity Distinct From Non-Functioning Pituitary Tumors - poster presentation
*
Pttg (Pituitary tumor transforming gene) is Required for Pituitary Tumor Development in Rb+/- Mice by Preventing p21-dependent Senescence - poster presentation
*
Identification of Murine Pituitary Tumor Progenitor Cells - oral presentation
The first in Southern California and one of only 10 hospitals in the state whose nurses have been honored with the prestigious Magnet designation, Cedars-Sinai Medical Center is one of the largest nonprofit academic medical centers in the Western United States. For 19 consecutive years, it has been named Los Angeles' most preferred hospital for all health needs in an independent survey of area residents. Cedars-Sinai is internationally renowned for its diagnostic and treatment capabilities as well as breakthroughs in biomedical research and superlative medical education. It ranks among the top 10 non-university hospitals in the nation for its research activities and is fully accredited by the Association for the Accreditation of Human Research Protection Programs, Inc. (AAHRPP). Additional information is available at cedars-sinai/.
Contact: Simi Singer
Cedars-Sinai Medical Center
Introns: A Mystery Renewed
The sequences of nonsense DNA that interrupt genes could be far more important to the evolution of genomes than previously thought, according to a recent Science report by Indiana University Bloomington and University of New Hampshire biologists.
Their study of the model organism Daphnia pulex (water flea) is the first to demonstrate the colonization of a single lineage by "introns," as the interrupting sequences are known. The scientists say introns are inserted into the genome far more frequently than current models predict. The scientists also found what appear to be "hot spots" for intron insertion -- areas of the genome where repeated insertions are more likely to occur. And surprisingly, the vast majority of intron DNA sequences the scientists examined were of unknown origin.
"The thinking has been that these insertion events are very rare because they always have bad effects," said postdoctoral fellow Abraham Tucker, a lead author of the Science paper.
Graduate student Wenli Li, whose participation in the research overlaps her dissertation work, was the paper's co-lead author. Li said she was particularly interested in the notion of hot spots that make it more likely for separate lineages of Daphnia to gain introns in the same place (or the same general area) within the water fleas' genomes. Four of the 23 different kinds of introns the scientists found were not unique with respect to position. If introns were always inserted in random places within genes, the scientists would have expected zero introns to have identical insertion points.
"The most intriguing finding for me is the multiple instances of parallel intron gains, because this means that Daphnia is in an active phase of intron proliferation," Li said. "This makes Daphnia an extraordinary system to study intron evolution. In addition, we believe our work facilitates a more accurate estimate of intron gain rates, and directly challenges the assumption that parallel intron gains are rare in many prior analyses."
Whether or not Daphnia is typical of eukaryotes with respect to intron gain (and loss), IU Bloomington evolutionary biologist Michael Lynch, the project's principal investigator, agreed that the discovery of parallelism will surprise his colleagues.
"Remarkably, we have found many cases of parallel intron gains at essentially the same sites in independent genotypes," Lynch said. "This strongly argues against the common assumption that when two species share introns at the same site, it is always due to inheritance from a common ancestor."
A unique and important aspect of the scientists' work is that they focused on one species (Daphnia pulex). Past studies have looked at a few introns shared by vastly different species. In doing so, geneticists have almost certainly missed the ephemeral appearance of new introns, and therefore would come to the wrong conclusions about how introns are gained, why they are lost, and how frequently either occurs.
That many introns are not acquired from a common ancestor but are the result of separate insertion events, the scientists say, means that the rates of intron gain in any species' lineage could be considerably higher than currently estimated.
Even if the rates of intron gain and loss of introns in Daphnia pulex are unlike those found in humans, sunflowers, and mushrooms, the Science report suggests geneticists and genome biologists take another look at introns, some of which could have been the result of hot spot insertion events in separate lines.
"The immediate question will be whether our findings can readily be extended to other species," Lynch said. "We are, in fact, doing that now. In addition, there is need for some solid molecular work to test our hypothesis about the mechanism of intron origin."
Intron is short for "intragenic region," a segment of DNA embedded within the coding portion of a gene. Introns are common in eukaryotic organisms -- animals, plants, fungi, and protists. When genes are expressed, special machinery within the cell nucleus usually removes the introns, thereby producing a transcript of the gene that is devoid of nonsense. Some introns are very small (20 DNA base pairs or fewer). A few introns are shockingly long (nearly 500,000 base pairs) long. Within a gene region, the total length of introns may dwarf the actual coding regions. There's a gene on humans' 22nd chromosome that is so riddled with introns, only 10 percent of it actually contains coding DNA. The rest is comprised of introns.
Scientists have generally assumed introns are so deleterious, their insertion almost always spells doom for the cell lines within individual organisms that produce offspring. With the exception of alternative splicing, introns serve no apparent function and consume needless energy when cells must duplicate all of their DNA. More importantly, the insertion of a new intron in a bad place can interfere with the cellular machinery's expression of an important gene. Experts have taken all of this to mean intron insertions are extremely rare events.
Almost all of the introns the IU Bloomington biologists located possessed a sequence of indeterminate origin. Only one of the 24 identified sequences bore a resemblance to a specific DNA sequences associated either with the Daphnia genome or its parasites. The other 23 introns had sequences that appear to have been improvised by the machinery responsible for DNA synthesis. "Our molecular analyses have enabled us to reject a number of hypotheses for the mechanism of intron origins, while clearly indicating an entirely unexpected pathway -- emergence as accidents arising during the repair of double-strand breaks," Lynch said.
Abraham Tucker, now at Indiana University Bloomington, and paper co-author Way Sung were both graduate students of William Kelley Thomas at the University of New Hampshire's Hubbard Center for Genome Studies when they did the bioinformatic analysis of the Daphnia genome that led to the findings of this paper. Drawing on longtime collaborations between Lynch's lab and the Hubbard Center on the Daphnia genome project, the two were able to access all Daphnia genome sequences.
"It was a very intense analysis, but it was obvious within a few days that there was some very interesting data," says Thomas, who is Hubbard Professor in Genomics and director of the Hubbard Center for Genome Studies. "This was a wonderful collaborative project."
This research was funded with grants from the National Science Foundation.
"Extensive, Recent Intron Gains in Daphnia Populations" Science, v. 326, pp. 1260-1262
Source: David Bricker
Indiana University
Their study of the model organism Daphnia pulex (water flea) is the first to demonstrate the colonization of a single lineage by "introns," as the interrupting sequences are known. The scientists say introns are inserted into the genome far more frequently than current models predict. The scientists also found what appear to be "hot spots" for intron insertion -- areas of the genome where repeated insertions are more likely to occur. And surprisingly, the vast majority of intron DNA sequences the scientists examined were of unknown origin.
"The thinking has been that these insertion events are very rare because they always have bad effects," said postdoctoral fellow Abraham Tucker, a lead author of the Science paper.
Graduate student Wenli Li, whose participation in the research overlaps her dissertation work, was the paper's co-lead author. Li said she was particularly interested in the notion of hot spots that make it more likely for separate lineages of Daphnia to gain introns in the same place (or the same general area) within the water fleas' genomes. Four of the 23 different kinds of introns the scientists found were not unique with respect to position. If introns were always inserted in random places within genes, the scientists would have expected zero introns to have identical insertion points.
"The most intriguing finding for me is the multiple instances of parallel intron gains, because this means that Daphnia is in an active phase of intron proliferation," Li said. "This makes Daphnia an extraordinary system to study intron evolution. In addition, we believe our work facilitates a more accurate estimate of intron gain rates, and directly challenges the assumption that parallel intron gains are rare in many prior analyses."
Whether or not Daphnia is typical of eukaryotes with respect to intron gain (and loss), IU Bloomington evolutionary biologist Michael Lynch, the project's principal investigator, agreed that the discovery of parallelism will surprise his colleagues.
"Remarkably, we have found many cases of parallel intron gains at essentially the same sites in independent genotypes," Lynch said. "This strongly argues against the common assumption that when two species share introns at the same site, it is always due to inheritance from a common ancestor."
A unique and important aspect of the scientists' work is that they focused on one species (Daphnia pulex). Past studies have looked at a few introns shared by vastly different species. In doing so, geneticists have almost certainly missed the ephemeral appearance of new introns, and therefore would come to the wrong conclusions about how introns are gained, why they are lost, and how frequently either occurs.
That many introns are not acquired from a common ancestor but are the result of separate insertion events, the scientists say, means that the rates of intron gain in any species' lineage could be considerably higher than currently estimated.
Even if the rates of intron gain and loss of introns in Daphnia pulex are unlike those found in humans, sunflowers, and mushrooms, the Science report suggests geneticists and genome biologists take another look at introns, some of which could have been the result of hot spot insertion events in separate lines.
"The immediate question will be whether our findings can readily be extended to other species," Lynch said. "We are, in fact, doing that now. In addition, there is need for some solid molecular work to test our hypothesis about the mechanism of intron origin."
Intron is short for "intragenic region," a segment of DNA embedded within the coding portion of a gene. Introns are common in eukaryotic organisms -- animals, plants, fungi, and protists. When genes are expressed, special machinery within the cell nucleus usually removes the introns, thereby producing a transcript of the gene that is devoid of nonsense. Some introns are very small (20 DNA base pairs or fewer). A few introns are shockingly long (nearly 500,000 base pairs) long. Within a gene region, the total length of introns may dwarf the actual coding regions. There's a gene on humans' 22nd chromosome that is so riddled with introns, only 10 percent of it actually contains coding DNA. The rest is comprised of introns.
Scientists have generally assumed introns are so deleterious, their insertion almost always spells doom for the cell lines within individual organisms that produce offspring. With the exception of alternative splicing, introns serve no apparent function and consume needless energy when cells must duplicate all of their DNA. More importantly, the insertion of a new intron in a bad place can interfere with the cellular machinery's expression of an important gene. Experts have taken all of this to mean intron insertions are extremely rare events.
Almost all of the introns the IU Bloomington biologists located possessed a sequence of indeterminate origin. Only one of the 24 identified sequences bore a resemblance to a specific DNA sequences associated either with the Daphnia genome or its parasites. The other 23 introns had sequences that appear to have been improvised by the machinery responsible for DNA synthesis. "Our molecular analyses have enabled us to reject a number of hypotheses for the mechanism of intron origins, while clearly indicating an entirely unexpected pathway -- emergence as accidents arising during the repair of double-strand breaks," Lynch said.
Abraham Tucker, now at Indiana University Bloomington, and paper co-author Way Sung were both graduate students of William Kelley Thomas at the University of New Hampshire's Hubbard Center for Genome Studies when they did the bioinformatic analysis of the Daphnia genome that led to the findings of this paper. Drawing on longtime collaborations between Lynch's lab and the Hubbard Center on the Daphnia genome project, the two were able to access all Daphnia genome sequences.
"It was a very intense analysis, but it was obvious within a few days that there was some very interesting data," says Thomas, who is Hubbard Professor in Genomics and director of the Hubbard Center for Genome Studies. "This was a wonderful collaborative project."
This research was funded with grants from the National Science Foundation.
"Extensive, Recent Intron Gains in Daphnia Populations" Science, v. 326, pp. 1260-1262
Source: David Bricker
Indiana University
First Examples Of RNA That Replicates Itself Indefinitely Developed By Scripps Scientists
Findings could inform biochemical questions about how life began#
Now, a pair of Scripps Research Institute scientists has taken a significant step toward answering that question. The scientists have synthesized for the first time RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely.
The work was published on in Science Express, the advanced, online edition of the journal Science.
In the modern world, DNA carries the genetic sequence for advanced organisms, while RNA is dependent on DNA for performing its roles such as building proteins. But one prominent theory about the origins of life, called the RNA World model, postulates that because RNA can function as both a gene and an enzyme, RNA might have come before DNA and protein and acted as the ancestral molecule of life. However, the process of copying a genetic molecule, which is considered a basic qualification for life, appears to be exceedingly complex, involving many proteins and other cellular components.
For years, researchers have wondered whether there might be some simpler way to copy RNA, brought about by the RNA itself. Some tentative steps along this road had previously been taken by the Joyce lab and others, but no one could demonstrate that RNA replication could be self-propagating, that is, result in new copies of RNA that also could copy themselves.
In Vitro Evolution
A few years after Tracey Lincoln arrived at Scripps Research from Jamaica to pursue her Ph.D., she began exploring the RNA-only replication concept along with her advisor, Professor Gerald Joyce, M.D., Ph.D., who is also Dean of the Faculty at Scripps Research. Their work began with a method of forced adaptation known as in vitro evolution. The goal was to take one of the RNA enzymes already developed in the lab that could perform the basic chemistry of replication, and improve it to the point that it could drive efficient, perpetual self-replication.
Lincoln synthesized in the laboratory a large population of variants of the RNA enzyme that would be challenged to do the job, and carried out a test-tube evolution procedure to obtain those variants that were most adept at joining together pieces of RNA.
Ultimately, this process enabled the team to isolate an evolved version of the original enzyme that is a very efficient replicator, something that many research groups, including Joyce's, had struggled for years to obtain. The improved enzyme fulfilled the primary goal of being able to undergo perpetual replication. "It kind of blew me away," says Lincoln.
Immortalizing Molecular Information
The replicating system actually involves two enzymes, each composed of two subunits and each functioning as a catalyst that assembles the other. The replication process is cyclic, in that the first enzyme binds the two subunits that comprise the second enzyme and joins them to make a new copy of the second enzyme; while the second enzyme similarly binds and joins the two subunits that comprise the first enzyme. In this way the two enzymes assemble each other - what is termed cross-replication. To make the process proceed indefinitely requires only a small starting amount of the two enzymes and a steady supply of the subunits.
"This is the only case outside biology where molecular information has been immortalized," says Joyce.
Not content to stop there, the researchers generated a variety of enzyme pairs with similar capabilities. They mixed 12 different cross-replicating pairs, together with all of their constituent subunits, and allowed them to compete in a molecular test of survival of the fittest. Most of the time the replicating enzymes would breed true, but on occasion an enzyme would make a mistake by binding one of the subunits from one of the other replicating enzymes. When such "mutations" occurred, the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture. "To me that's actually the biggest result," says Joyce.
The research shows that the system can sustain molecular information, a form of heritability, and give rise to variations of itself in a way akin to Darwinian evolution. So, says Lincoln, "What we have is non-living, but we've been able to show that it has some life-like properties, and that was extremely interesting."
Knocking on the Door of Life
The group is pursuing potential applications of their discovery in the field of molecular diagnostics, but that work is tied to a research paper currently in review, so the researchers can't yet discuss it.
But the main value of the work, according to Joyce, is at the basic research level. "What we've found could be relevant to how life begins, at that key moment when Darwinian evolution starts." He is quick to point out that, while the self-replicating RNA enzyme systems share certain characteristics of life, they are not themselves a form of life.
The historical origin of life can never be recreated precisely, so without a reliable time machine, one must instead address the related question of whether life could ever be created in a laboratory. This could, of course, shed light on what the beginning of life might have looked like, at least in outline. "We're not trying to play back the tape," says Lincoln of their work, "but it might tell us how you go about starting the process of understanding the emergence of life in the lab."
Joyce says that only when a system is developed in the lab that has the capability of evolving novel functions on its own can it be properly called life. "We're knocking on that door," he says, "But of course we haven't achieved that."
The subunits in the enzymes the team constructed each contain many nucleotides, so they are relatively complex and not something that would have been found floating in the primordial ooze. But, while the building blocks likely would have been simpler, the work does finally show that a simpler form of RNA-based life is at least possible, which should drive further research to explore the RNA World theory of life's origins.
The paper is titled "Self-sustained Replication of an RNA Enzyme," and the work was supported by NASA and the National Institutes of Health, and the Skaggs Institute for Chemical Biology.
About The Scripps Research Institute
The Scripps Research Institute is one of the world's largest independent, non-profit biomedical research organizations, at the forefront of basic biomedical science that seeks to comprehend the most fundamental processes of life. Scripps Research is internationally recognized for its discoveries in immunology, molecular and cellular biology, chemistry, neurosciences, autoimmune, cardiovascular, and infectious diseases, and synthetic vaccine development. Established in its current configuration in 1961, it employs approximately 3,000 scientists, postdoctoral fellows, scientific and other technicians, doctoral degree graduate students, and administrative and technical support personnel. Scripps Research is headquartered in La Jolla, California. It also includes Scripps Florida, whose researchers focus on basic biomedical science, drug discovery, and technology development. Scripps Florida is currently in the process of moving from temporary facilities to its permanent campus in Jupiter, Florida. Dedication ceremonies for the new campus will be held in February 2009.
Source: Keith McKeown
Scripps Research Institute
Now, a pair of Scripps Research Institute scientists has taken a significant step toward answering that question. The scientists have synthesized for the first time RNA enzymes that can replicate themselves without the help of any proteins or other cellular components, and the process proceeds indefinitely.
The work was published on in Science Express, the advanced, online edition of the journal Science.
In the modern world, DNA carries the genetic sequence for advanced organisms, while RNA is dependent on DNA for performing its roles such as building proteins. But one prominent theory about the origins of life, called the RNA World model, postulates that because RNA can function as both a gene and an enzyme, RNA might have come before DNA and protein and acted as the ancestral molecule of life. However, the process of copying a genetic molecule, which is considered a basic qualification for life, appears to be exceedingly complex, involving many proteins and other cellular components.
For years, researchers have wondered whether there might be some simpler way to copy RNA, brought about by the RNA itself. Some tentative steps along this road had previously been taken by the Joyce lab and others, but no one could demonstrate that RNA replication could be self-propagating, that is, result in new copies of RNA that also could copy themselves.
In Vitro Evolution
A few years after Tracey Lincoln arrived at Scripps Research from Jamaica to pursue her Ph.D., she began exploring the RNA-only replication concept along with her advisor, Professor Gerald Joyce, M.D., Ph.D., who is also Dean of the Faculty at Scripps Research. Their work began with a method of forced adaptation known as in vitro evolution. The goal was to take one of the RNA enzymes already developed in the lab that could perform the basic chemistry of replication, and improve it to the point that it could drive efficient, perpetual self-replication.
Lincoln synthesized in the laboratory a large population of variants of the RNA enzyme that would be challenged to do the job, and carried out a test-tube evolution procedure to obtain those variants that were most adept at joining together pieces of RNA.
Ultimately, this process enabled the team to isolate an evolved version of the original enzyme that is a very efficient replicator, something that many research groups, including Joyce's, had struggled for years to obtain. The improved enzyme fulfilled the primary goal of being able to undergo perpetual replication. "It kind of blew me away," says Lincoln.
Immortalizing Molecular Information
The replicating system actually involves two enzymes, each composed of two subunits and each functioning as a catalyst that assembles the other. The replication process is cyclic, in that the first enzyme binds the two subunits that comprise the second enzyme and joins them to make a new copy of the second enzyme; while the second enzyme similarly binds and joins the two subunits that comprise the first enzyme. In this way the two enzymes assemble each other - what is termed cross-replication. To make the process proceed indefinitely requires only a small starting amount of the two enzymes and a steady supply of the subunits.
"This is the only case outside biology where molecular information has been immortalized," says Joyce.
Not content to stop there, the researchers generated a variety of enzyme pairs with similar capabilities. They mixed 12 different cross-replicating pairs, together with all of their constituent subunits, and allowed them to compete in a molecular test of survival of the fittest. Most of the time the replicating enzymes would breed true, but on occasion an enzyme would make a mistake by binding one of the subunits from one of the other replicating enzymes. When such "mutations" occurred, the resulting recombinant enzymes also were capable of sustained replication, with the most fit replicators growing in number to dominate the mixture. "To me that's actually the biggest result," says Joyce.
The research shows that the system can sustain molecular information, a form of heritability, and give rise to variations of itself in a way akin to Darwinian evolution. So, says Lincoln, "What we have is non-living, but we've been able to show that it has some life-like properties, and that was extremely interesting."
Knocking on the Door of Life
The group is pursuing potential applications of their discovery in the field of molecular diagnostics, but that work is tied to a research paper currently in review, so the researchers can't yet discuss it.
But the main value of the work, according to Joyce, is at the basic research level. "What we've found could be relevant to how life begins, at that key moment when Darwinian evolution starts." He is quick to point out that, while the self-replicating RNA enzyme systems share certain characteristics of life, they are not themselves a form of life.
The historical origin of life can never be recreated precisely, so without a reliable time machine, one must instead address the related question of whether life could ever be created in a laboratory. This could, of course, shed light on what the beginning of life might have looked like, at least in outline. "We're not trying to play back the tape," says Lincoln of their work, "but it might tell us how you go about starting the process of understanding the emergence of life in the lab."
Joyce says that only when a system is developed in the lab that has the capability of evolving novel functions on its own can it be properly called life. "We're knocking on that door," he says, "But of course we haven't achieved that."
The subunits in the enzymes the team constructed each contain many nucleotides, so they are relatively complex and not something that would have been found floating in the primordial ooze. But, while the building blocks likely would have been simpler, the work does finally show that a simpler form of RNA-based life is at least possible, which should drive further research to explore the RNA World theory of life's origins.
The paper is titled "Self-sustained Replication of an RNA Enzyme," and the work was supported by NASA and the National Institutes of Health, and the Skaggs Institute for Chemical Biology.
About The Scripps Research Institute
The Scripps Research Institute is one of the world's largest independent, non-profit biomedical research organizations, at the forefront of basic biomedical science that seeks to comprehend the most fundamental processes of life. Scripps Research is internationally recognized for its discoveries in immunology, molecular and cellular biology, chemistry, neurosciences, autoimmune, cardiovascular, and infectious diseases, and synthetic vaccine development. Established in its current configuration in 1961, it employs approximately 3,000 scientists, postdoctoral fellows, scientific and other technicians, doctoral degree graduate students, and administrative and technical support personnel. Scripps Research is headquartered in La Jolla, California. It also includes Scripps Florida, whose researchers focus on basic biomedical science, drug discovery, and technology development. Scripps Florida is currently in the process of moving from temporary facilities to its permanent campus in Jupiter, Florida. Dedication ceremonies for the new campus will be held in February 2009.
Source: Keith McKeown
Scripps Research Institute
Enzyme Important In Aging Identified By Scientists At Children's Hospital Of Pittsburgh Of UPMC
The secret to longevity may lie in an enzyme with the ability to promote a robust immune system into old age by maintaining the function of the thymus throughout life, according to researchers studying an "anti-aging" mouse model that lives longer than a typical mouse.
The study, led by Abbe de Vallejo, Ph.D., associate professor of pediatrics and immunology, University of Pittsburgh School of Medicine, and immunologist at Children's Hospital of Pittsburgh of UPMC, reports that the novel mouse model has a thymus that remains intact throughout its life. In all mammals, the thymus - the organ that produces T cells to fight disease and infection - degenerates with age.
Results of the study are published in this week's issue of the Proceedings of the National Academy of Sciences.
"These findings give us hope that we may one day have the ability to restore the function of the thymus in old age, or perhaps by intervening at an early age, we may be able to delay or even prevent the degeneration of the thymus in order to maintain our immune defenses throughout life," said Dr. de Vallejo.
The mouse model that Dr. de Vallejo's team studied was developed by his colleague Cheryl Conover, Ph.D., an endocrinology researcher at Mayo Clinic. In this "knockout" mouse model, researchers deleted an enzyme known as pregnancy-associated plasma protein A (PAPPA). PAPPA-knockout mice live at least 30 percent longer and have significantly lower occurrence of spontaneous tumors than typical mice.
PAPPA controls the availability in tissues of a hormone known as insulin-like growth factor (IGF) that is a promoter of cell division. Hence, IGF is required for normal embryonic and postnatal growth. But IGF also is associated with tumor growth, inflammation and cardiovascular disease in adults. By deleting PAPPA, the researchers were able to control the availability of IGF in tissues and dampen its many ill effects. In the thymus, deletion of PAPPA maintained just enough IGF to sustain production of T cells without consuming precursor cells, thereby preventing the degeneration of the thymus.
"Controlling the availability of IGF in the thymus by targeted manipulation of PAPPA could be a way to maintain immune protection throughout life," Dr. de Vallejo said. "This study has profound implications for the future study of healthy aging and longevity."
Source:
Marc Lukasiak
University of Pittsburgh Schools of the Health Sciences
The study, led by Abbe de Vallejo, Ph.D., associate professor of pediatrics and immunology, University of Pittsburgh School of Medicine, and immunologist at Children's Hospital of Pittsburgh of UPMC, reports that the novel mouse model has a thymus that remains intact throughout its life. In all mammals, the thymus - the organ that produces T cells to fight disease and infection - degenerates with age.
Results of the study are published in this week's issue of the Proceedings of the National Academy of Sciences.
"These findings give us hope that we may one day have the ability to restore the function of the thymus in old age, or perhaps by intervening at an early age, we may be able to delay or even prevent the degeneration of the thymus in order to maintain our immune defenses throughout life," said Dr. de Vallejo.
The mouse model that Dr. de Vallejo's team studied was developed by his colleague Cheryl Conover, Ph.D., an endocrinology researcher at Mayo Clinic. In this "knockout" mouse model, researchers deleted an enzyme known as pregnancy-associated plasma protein A (PAPPA). PAPPA-knockout mice live at least 30 percent longer and have significantly lower occurrence of spontaneous tumors than typical mice.
PAPPA controls the availability in tissues of a hormone known as insulin-like growth factor (IGF) that is a promoter of cell division. Hence, IGF is required for normal embryonic and postnatal growth. But IGF also is associated with tumor growth, inflammation and cardiovascular disease in adults. By deleting PAPPA, the researchers were able to control the availability of IGF in tissues and dampen its many ill effects. In the thymus, deletion of PAPPA maintained just enough IGF to sustain production of T cells without consuming precursor cells, thereby preventing the degeneration of the thymus.
"Controlling the availability of IGF in the thymus by targeted manipulation of PAPPA could be a way to maintain immune protection throughout life," Dr. de Vallejo said. "This study has profound implications for the future study of healthy aging and longevity."
Source:
Marc Lukasiak
University of Pittsburgh Schools of the Health Sciences
To Contract Or Not To Contract: Decision Controlled By 2 MicroRNAs
The walls of blood vessels contain muscle cells known as vascular smooth muscle cells (VSMCs). These cells contract and relax to modulate blood pressure and distribute blood to the areas of the body that need it most. However, some environmental signals, many of which are associated with human disease, cause VSMCs to switch from being contractile in nature to being dividing cells that produce large amounts of the proteins that form tissue matrix. Despite the fact that this switch has been associated with a number of human blood vessel diseases, the mechanisms that control it have not been well defined. However, a team of researchers at the Max-Planck-Institut fГјr Herz- und Lungenforschung, Germany, has now identified two small RNA molecules (microRNAs) known miR-143 and miR-145 that regulate acquisition and/or maintenance of the contractile nature of VSMCs in mice.
The team, led by Thomas Braun and Thomas Boettger, generated mice lacking both miR-143 and miR-145 and found that they had dramatically reduced numbers of contractile VSMCs and increased numbers of tissue matrix-producing VSMCs in their large arterial blood vessels. Further analysis revealed that these two small RNA molecules were required for normal contractility of arteries in vitro and maintenance of normal blood pressure in vivo. As their absence led to signs of blood vessel disease in mice, the authors suggest that miR-143/145 might provide new therapeutic targets to enhance blood vessel repair and attenuate blood vessel disease.
In an accompanying commentary, Michael Parmacek, at the University of Pennsylvania School of Medicine, Philadelphia, discusses the importance of this study and highlights the fact that miR-143 and miR-145 were found to alter the expression of differing sets of genes, meaning that future studies will need to determine precisely how they alter control of blood pressure and disease development.
TITLE: Acquisition of the contractile phenotype by murine arterial smooth muscle cells depends on the Mir143/145 gene cluster https://the-jci/article.php?id=38864
ACCOMPANYING COMMENTARY
TITLE: MicroRNA-modulated targeting of vascular smooth muscle cells https://the-jci/article.php?id=40503
Source:
Karen Honey
Journal of Clinical Investigation
The team, led by Thomas Braun and Thomas Boettger, generated mice lacking both miR-143 and miR-145 and found that they had dramatically reduced numbers of contractile VSMCs and increased numbers of tissue matrix-producing VSMCs in their large arterial blood vessels. Further analysis revealed that these two small RNA molecules were required for normal contractility of arteries in vitro and maintenance of normal blood pressure in vivo. As their absence led to signs of blood vessel disease in mice, the authors suggest that miR-143/145 might provide new therapeutic targets to enhance blood vessel repair and attenuate blood vessel disease.
In an accompanying commentary, Michael Parmacek, at the University of Pennsylvania School of Medicine, Philadelphia, discusses the importance of this study and highlights the fact that miR-143 and miR-145 were found to alter the expression of differing sets of genes, meaning that future studies will need to determine precisely how they alter control of blood pressure and disease development.
TITLE: Acquisition of the contractile phenotype by murine arterial smooth muscle cells depends on the Mir143/145 gene cluster https://the-jci/article.php?id=38864
ACCOMPANYING COMMENTARY
TITLE: MicroRNA-modulated targeting of vascular smooth muscle cells https://the-jci/article.php?id=40503
Source:
Karen Honey
Journal of Clinical Investigation
Identification Of Cause Of Mussel Poisoning
The origin of the neurotoxin azaspiracid has finally been identified after a search for more than a decade. The azaspiracid toxin group can cause severe poisoning in human consumers of mussels after being enriched in the shellfish tissues. The scientific periodical European Journal of Phycology reports in its current issue (Vol. 44/1: p. 63-79) that a tiny algal species, the dinoflagellate Azadinium spinosum, is responsible. Researchers from the Alfred Wegener Institute for Polar and Marine Research in the Helmholtz Association have isolated and described the hitherto unknown organism as a new genus and species of dinoflagellate. They successfully isolated the organism and multiplied it in pure laboratory cultures, subsequently identifying it as the producer of azaspiracid toxin.
Eating mussels is a special treat for many people, although it is not completely without danger. It has been known for a long time that consumption of mussels and other bivalve shellfish can cause poisoning in humans, with symptoms ranging from diarrhea, nausea, and vomiting to neurotoxicological effects, including paralysis and even death in extreme cases. Although "shellfish poisoning" can also be caused by pathogenic viruses and bacteria, many cases are due to gastrointestinal toxins and/or neurotoxins produced by certain marine microscopic plankton, the so-called "toxic algae". Mussels can filter a high amount of these toxic microorganisms from the seawater column, and after ingestion they retain the toxins and accumulate them in their edible flesh.
Azaspiracids comprise one group of these microalgal toxins The first known azaspiracid poisonings occurred in the Netherlands in 1995 after consumption of mussels from Ireland. While the toxin itself has been quite well investigated, the question of the origin remained inconclusive until now, despite intensive research. According to published investigations by Irish researchers, the dinoflagellate species Protoperidinium crassipes (previously regarded as harmless) has been blamed as the origin of the toxins since 2003. Researchers from the Working Group on Ecological Chemistry, particularly the biologist Dr. Urban Tillmann and the chemist Dr. Bernd Krock from the Alfred Wegener Institute for Polar and Marine Research were able to show that Protoperidinium is only the vector and not the producer of the toxins, just like other voracious protozoa and mussels. They isolated a small alga from the North Sea off the Scottish east coast and described it as a new dinoflagellate species Azadinium spinosum while providing evidence of its azaspiracid production in the laboratory.
"We are able to produce so-called gene probes from our laboratory cultures with the help of molecular techniques", explains Tillmann. "These gene probes prove the existence of the toxin-producing algae in seawater samples and they offer an effective future early warning system for mussel farms", Tillmann continues. Apart from these applied aspects, the researchers are interested in quite fundamental questions: why does the alga produce these azaspiracid toxins and what are their ecological functions? The researchers have already planned the next expedition in order to further pursue these questions - they will head out into the North Sea with RV Heincke at the end of April 2009.
Notes:
The Alfred Wegener Institute carries out research in the Arctic and Antarctic as well as in the high and mid latitude oceans. The institute coordinates German polar research and makes available to international science important infrastructure, e.g. the research ice breaker "Polarstern" and research stations in the Arctic and Antarctic. AWI is one of 15 research centres within the Helmholtz-Gesellschaft, Germany's largest scientific organization.
Source:
Ude Cieluch
Helmholtz Association of German Research Centres
Eating mussels is a special treat for many people, although it is not completely without danger. It has been known for a long time that consumption of mussels and other bivalve shellfish can cause poisoning in humans, with symptoms ranging from diarrhea, nausea, and vomiting to neurotoxicological effects, including paralysis and even death in extreme cases. Although "shellfish poisoning" can also be caused by pathogenic viruses and bacteria, many cases are due to gastrointestinal toxins and/or neurotoxins produced by certain marine microscopic plankton, the so-called "toxic algae". Mussels can filter a high amount of these toxic microorganisms from the seawater column, and after ingestion they retain the toxins and accumulate them in their edible flesh.
Azaspiracids comprise one group of these microalgal toxins The first known azaspiracid poisonings occurred in the Netherlands in 1995 after consumption of mussels from Ireland. While the toxin itself has been quite well investigated, the question of the origin remained inconclusive until now, despite intensive research. According to published investigations by Irish researchers, the dinoflagellate species Protoperidinium crassipes (previously regarded as harmless) has been blamed as the origin of the toxins since 2003. Researchers from the Working Group on Ecological Chemistry, particularly the biologist Dr. Urban Tillmann and the chemist Dr. Bernd Krock from the Alfred Wegener Institute for Polar and Marine Research were able to show that Protoperidinium is only the vector and not the producer of the toxins, just like other voracious protozoa and mussels. They isolated a small alga from the North Sea off the Scottish east coast and described it as a new dinoflagellate species Azadinium spinosum while providing evidence of its azaspiracid production in the laboratory.
"We are able to produce so-called gene probes from our laboratory cultures with the help of molecular techniques", explains Tillmann. "These gene probes prove the existence of the toxin-producing algae in seawater samples and they offer an effective future early warning system for mussel farms", Tillmann continues. Apart from these applied aspects, the researchers are interested in quite fundamental questions: why does the alga produce these azaspiracid toxins and what are their ecological functions? The researchers have already planned the next expedition in order to further pursue these questions - they will head out into the North Sea with RV Heincke at the end of April 2009.
Notes:
The Alfred Wegener Institute carries out research in the Arctic and Antarctic as well as in the high and mid latitude oceans. The institute coordinates German polar research and makes available to international science important infrastructure, e.g. the research ice breaker "Polarstern" and research stations in the Arctic and Antarctic. AWI is one of 15 research centres within the Helmholtz-Gesellschaft, Germany's largest scientific organization.
Source:
Ude Cieluch
Helmholtz Association of German Research Centres
Older Siblings May Outcompete Their Younger Siblings But Are Least Likely To Make It To The Competition At All
You are a younger child in your family, and your older siblings use their size and age advantage to exercise their dominance, leaving you, invariably,
with the smallest piece of the pie. If this sounds familiar, rest assured that you are not alone in the animal kingdom and, in fact, you should be
happy to survive long enough to get any pie at all.
Many organisms, not just humans, produce offspring in series and then rear these dependents simultaneously, setting the stage for a
competition-mediated probability of post-natal hardship that depends on the order in which the individual offspring was produced.
Birds are famous for this, whereby the earliest laid eggs hatch first, and hatchlings gain an initial competitive advantage over younger siblings. As
a result, the youngest often dies from being out-competed for limited resources provided by the parents. However, many researchers that have
documented this phenomenon, whereby probability of mortality increases with laying order within the brood, have not accounted for viability
differences during other periods of the life cycle, in particular during the pre- hatching period.
Keith Sockman, an Assistant Professor of Biology at the University of North Carolina at Chapel Hill and the third of four sibling offspring, has
discovered that, in Lincoln's sparrows, the first-produced offspring is indeed the most likely to win the battle of post-hatching sibling competition.
However, the first-produced are the least likely to make it to the competition at all because they are the least likely to hatch. This may be due to
maternal neglect of the first-produced embryos while the mother is busy producing the subsequently laid siblings. Thus, ovulation order mediates a
trade- off between pre-hatching and post-hatching viability. This trade-off ultimately results in a relatively even distribution among siblings in
their probability of surviving the complete nesting cycle, from laying through incubation, the nestling stage, and finally fledging.
Sockman's findings are published this week in the journal PLoS ONE.
Ovulation Order Mediates a Trade-Off between Pre-Hatching and Post-Hatching Viability in an Altricial Bird.
Sockman KW
PLoS ONE 3(3): e1785. doi:10.1371/journal.pone.0001785
Please click here to view article online
Public Library of Science
185 Berry Street, Suite 3100
San Francisco, CA 94107
USA
with the smallest piece of the pie. If this sounds familiar, rest assured that you are not alone in the animal kingdom and, in fact, you should be
happy to survive long enough to get any pie at all.
Many organisms, not just humans, produce offspring in series and then rear these dependents simultaneously, setting the stage for a
competition-mediated probability of post-natal hardship that depends on the order in which the individual offspring was produced.
Birds are famous for this, whereby the earliest laid eggs hatch first, and hatchlings gain an initial competitive advantage over younger siblings. As
a result, the youngest often dies from being out-competed for limited resources provided by the parents. However, many researchers that have
documented this phenomenon, whereby probability of mortality increases with laying order within the brood, have not accounted for viability
differences during other periods of the life cycle, in particular during the pre- hatching period.
Keith Sockman, an Assistant Professor of Biology at the University of North Carolina at Chapel Hill and the third of four sibling offspring, has
discovered that, in Lincoln's sparrows, the first-produced offspring is indeed the most likely to win the battle of post-hatching sibling competition.
However, the first-produced are the least likely to make it to the competition at all because they are the least likely to hatch. This may be due to
maternal neglect of the first-produced embryos while the mother is busy producing the subsequently laid siblings. Thus, ovulation order mediates a
trade- off between pre-hatching and post-hatching viability. This trade-off ultimately results in a relatively even distribution among siblings in
their probability of surviving the complete nesting cycle, from laying through incubation, the nestling stage, and finally fledging.
Sockman's findings are published this week in the journal PLoS ONE.
Ovulation Order Mediates a Trade-Off between Pre-Hatching and Post-Hatching Viability in an Altricial Bird.
Sockman KW
PLoS ONE 3(3): e1785. doi:10.1371/journal.pone.0001785
Please click here to view article online
Public Library of Science
185 Berry Street, Suite 3100
San Francisco, CA 94107
USA
MIT: Computer Model Reveals Cells' Inner Workings - New Approach Could Help Tailor Chemotherapy Treatments
After spending years developing a computational model to help illuminate cell signaling pathways, a team of MIT researchers decided to see what would happen if they "broke" the model.
The results, reported in the Oct. 17 issue of the journal Cell, reveal new ways in which cells process chemical information and could indicate how to maximize the effectiveness of disease treatments such as chemotherapy.
A couple of years ago, MIT faculty member Michael Yaffe and colleagues reported a data-driven computational model that allows them to simultaneously investigate the relationships between several cell signaling pathways, which control the cell's response to inflammation, growth factors, DNA damage and other events.
Such a model can help researchers figure out how cells will respond to growth factors and treatments like chemotherapy, allowing them to potentially tailor treatments to individual patients.
In the Cell paper, the team took a new approach to wring more information out of their model: They looked at what happens in cells under conditions where the model fails catastrophically. This approach, which the authors call "model breakpoint analysis," is an extension of more traditional failure analysis methods commonly used by engineers to figure out what design changes would make a bridge fall down or an engine fail.
"In traditional engineering sciences, you frequently use computational methods to predict what effect a faulty strut or a broken wire will have on a plane or an electronic circuit - will it fail, and if so, when and how?" said Yaffe, associate professor of biology and biological engineering and senior author of the new paper.
Doing the same thing in cellular models can reveal important and previously unexplored aspects of the signaling pathways.
To "break" the computer model, the researchers entered increasingly implausible inputs to the model until it no longer correctly predicted cell fate. To their surprise, they found that the model remained accurate for a long time.
"As the data we used to build the model got progressively worse and worse - more and more biologically inaccurate - the model would work fine, and then when you got to a certain threshold - the breakpoint - the model suddenly wouldn't predict anymore," said Yaffe, who is affiliated with MIT's David H. Koch Institute for Integrative Cancer Research, the Broad Institute of MIT and Harvard, and Beth Israel Deaconess Medical Center.
"By going back and looking at what happened in the model when the predictions failed, we discovered a surprising amount of new biology that was actually happening in the living cell," Yaffe said.
One significant, unexpected finding is the observation that both overactive and underactive mutations within a particular gene, such as those found in cancer, reduce cell death compared to the normal gene. This suggests that normal cells are poised to die whenever there is trouble, but perhaps not tumor cells.
That means the dynamic range of cell signaling - the spread between the highest and lowest levels of a biological signal, like the range of volumes you can hear on your stereo - may be a greater determinant of what cells do than the absolute level of a particular signal, said Yaffe.
The computer modeling approach offers the chance to learn about biological phenomena that might take thousands of hours in the laboratory to uncover, according to Yaffe.
"In addition, rather than looking at one pathway in the cell in isolation, we could look at five pathways or eight pathways simultaneously," he said. "It also reinforces how engineering ideas can really illuminate biological mechanisms."
Lead authors of the paper are Kevin Janes, a recent MIT PhD recipient, and H. Christian Reinhardt, a postdoctoral associate in the Koch Institute.
This research was funded by the National Institutes of Health, the Deutsche Forschungsgemeinschaft, the David H. Koch Fund, the Edgerly Innovation Fund and the American Cancer Society.
Source:
Anne Trafton
MIT
The results, reported in the Oct. 17 issue of the journal Cell, reveal new ways in which cells process chemical information and could indicate how to maximize the effectiveness of disease treatments such as chemotherapy.
A couple of years ago, MIT faculty member Michael Yaffe and colleagues reported a data-driven computational model that allows them to simultaneously investigate the relationships between several cell signaling pathways, which control the cell's response to inflammation, growth factors, DNA damage and other events.
Such a model can help researchers figure out how cells will respond to growth factors and treatments like chemotherapy, allowing them to potentially tailor treatments to individual patients.
In the Cell paper, the team took a new approach to wring more information out of their model: They looked at what happens in cells under conditions where the model fails catastrophically. This approach, which the authors call "model breakpoint analysis," is an extension of more traditional failure analysis methods commonly used by engineers to figure out what design changes would make a bridge fall down or an engine fail.
"In traditional engineering sciences, you frequently use computational methods to predict what effect a faulty strut or a broken wire will have on a plane or an electronic circuit - will it fail, and if so, when and how?" said Yaffe, associate professor of biology and biological engineering and senior author of the new paper.
Doing the same thing in cellular models can reveal important and previously unexplored aspects of the signaling pathways.
To "break" the computer model, the researchers entered increasingly implausible inputs to the model until it no longer correctly predicted cell fate. To their surprise, they found that the model remained accurate for a long time.
"As the data we used to build the model got progressively worse and worse - more and more biologically inaccurate - the model would work fine, and then when you got to a certain threshold - the breakpoint - the model suddenly wouldn't predict anymore," said Yaffe, who is affiliated with MIT's David H. Koch Institute for Integrative Cancer Research, the Broad Institute of MIT and Harvard, and Beth Israel Deaconess Medical Center.
"By going back and looking at what happened in the model when the predictions failed, we discovered a surprising amount of new biology that was actually happening in the living cell," Yaffe said.
One significant, unexpected finding is the observation that both overactive and underactive mutations within a particular gene, such as those found in cancer, reduce cell death compared to the normal gene. This suggests that normal cells are poised to die whenever there is trouble, but perhaps not tumor cells.
That means the dynamic range of cell signaling - the spread between the highest and lowest levels of a biological signal, like the range of volumes you can hear on your stereo - may be a greater determinant of what cells do than the absolute level of a particular signal, said Yaffe.
The computer modeling approach offers the chance to learn about biological phenomena that might take thousands of hours in the laboratory to uncover, according to Yaffe.
"In addition, rather than looking at one pathway in the cell in isolation, we could look at five pathways or eight pathways simultaneously," he said. "It also reinforces how engineering ideas can really illuminate biological mechanisms."
Lead authors of the paper are Kevin Janes, a recent MIT PhD recipient, and H. Christian Reinhardt, a postdoctoral associate in the Koch Institute.
This research was funded by the National Institutes of Health, the Deutsche Forschungsgemeinschaft, the David H. Koch Fund, the Edgerly Innovation Fund and the American Cancer Society.
Source:
Anne Trafton
MIT
In Birds, Expecting To Mate Leads To Higher Fertilization Rates
From an evolutionary perspective, the primary task of an organism is to pass along its genes to future generations. Such genetic transmission is usually assumed to be instinctive. However, a new study shows that species also learn to adapt to their surroundings in order to increase their "reproductive fitness"-- the likelihood that they will successfully reproduce.
One form of learning that increases reproductive fitness is Pavlovian conditioning, the ability to associate a neutral stimulus with a stimulus of significance. The classic example comes from Ivan Pavlov and his dogs that eventually salivated at just the sound of a bell, because the bell had been preciously paired with a slab of meat. However, when it comes to reproduction, does learning contribute to more offspring?
Researchers from the University of Texas at Austin decided to test this in the laboratory. Nicolle Matthews and colleagues set out to examine whether learning can contribute to reproductive fitness in a particularly challenging situation -- when two males compete to fertilize the egg of a single female.
Matthews hypothesized that if two males mate with the same female compete to fertilize her eggs, paternity will favor the male that received a signal or conditioned stimulus before the mating session.
Using quail, Matthews put the males into two chambers for thirty minutes; they repeated this for five days. One chamber was green and was located on the floor near a noisy room and the other chamber was white, had a tilted floor, and was located in an isolated room on a table. Whenever the quails were in one of the two chambers, they were allowed access to a female. Thus, the quail learned to anticipate a chance to copulate whenever they were placed in this chamber but not when they were in the other.
On the test day, each female was allowed to copulate with two males. One of the males was in the chamber where he expected to receive access to a female and the other male was in a chamber where he did not expect a female. Using genetic markers, the researchers then collected the eggs of the female quail and tested the paternity.
The results, which appear in the September issue of Psychological Science, a journal of the Association for Psychological Science, are clear: The males who were placed in the context that led them to anticipate access to a female just before copulation fertilized seventy-two percent of the eggs laid by the female quail. In other words, the quail who knew they were going to have the opportunity to mate produced more offspring. This is a significant finding because typically when two males mate in quick succession with the same female, no differences in paternity are found, which Matthews confirmed in a follow-up experiment.
The researchers point out that the conditioning most likely had an effect on the rate of sperm release without changing sperm quality or concentration. "Learning and individual experience can bias genetic transmission and the evolutionary changes that result from sexual competition," write the authors.
Psychological Science is ranked among the top 10 general psychology journals for impact by the Institute for Scientific Information.
psychologicalscience
One form of learning that increases reproductive fitness is Pavlovian conditioning, the ability to associate a neutral stimulus with a stimulus of significance. The classic example comes from Ivan Pavlov and his dogs that eventually salivated at just the sound of a bell, because the bell had been preciously paired with a slab of meat. However, when it comes to reproduction, does learning contribute to more offspring?
Researchers from the University of Texas at Austin decided to test this in the laboratory. Nicolle Matthews and colleagues set out to examine whether learning can contribute to reproductive fitness in a particularly challenging situation -- when two males compete to fertilize the egg of a single female.
Matthews hypothesized that if two males mate with the same female compete to fertilize her eggs, paternity will favor the male that received a signal or conditioned stimulus before the mating session.
Using quail, Matthews put the males into two chambers for thirty minutes; they repeated this for five days. One chamber was green and was located on the floor near a noisy room and the other chamber was white, had a tilted floor, and was located in an isolated room on a table. Whenever the quails were in one of the two chambers, they were allowed access to a female. Thus, the quail learned to anticipate a chance to copulate whenever they were placed in this chamber but not when they were in the other.
On the test day, each female was allowed to copulate with two males. One of the males was in the chamber where he expected to receive access to a female and the other male was in a chamber where he did not expect a female. Using genetic markers, the researchers then collected the eggs of the female quail and tested the paternity.
The results, which appear in the September issue of Psychological Science, a journal of the Association for Psychological Science, are clear: The males who were placed in the context that led them to anticipate access to a female just before copulation fertilized seventy-two percent of the eggs laid by the female quail. In other words, the quail who knew they were going to have the opportunity to mate produced more offspring. This is a significant finding because typically when two males mate in quick succession with the same female, no differences in paternity are found, which Matthews confirmed in a follow-up experiment.
The researchers point out that the conditioning most likely had an effect on the rate of sperm release without changing sperm quality or concentration. "Learning and individual experience can bias genetic transmission and the evolutionary changes that result from sexual competition," write the authors.
Psychological Science is ranked among the top 10 general psychology journals for impact by the Institute for Scientific Information.
psychologicalscience
New Hope For Deadly Childhood Disease
Investigators at the University of Rochester Medical Center have uncovered a promising drug therapy that offers a ray of hope for children with Batten disease - a rare neurodegenerative disease that strikes seemingly healthy kids, progressively robs them of their abilities to see, reason and move, and ultimately kills them in their young twenties.
The study, highlighted in the January edition of Experimental Neurology, explains how investigators improved the motor skills of feeble mice that model the disease, helping them to better their scores on successive coordination tests.
"No treatment currently exists for these kids - nothing to halt the disease, or even to slow it down," said one of the study's authors, David Pearce, Ph.D., a nationally renowned Batten disease expert and biochemist at the University of Rochester. His team has published more than 50 studies on the disease's basic mechanisms.
"Since deterioration of motor skills is the rule - in fact, it's one of the primary symptoms in children with the disease - the idea that these functions might be able to be partially restored or improved is groundbreaking," Pearce said.
Last year, University of Rochester researchers discovered that, in mice with the disease, a set of the brain's receptor cells - known as the AMPA receptors - were unusually sensitive to glutamate, a neurotransmitter vital for learning and memory. These 'super-ticklish' receptors were located in the cerebellum, a brain region that plays a hefty role in sensory perception and motor control.
"For us, their abnormal activity made them key suspects in the brain dysfunction and neurological decline associated with the disease," Pearce said.
To test that, researchers administered a drug that partially blocks these receptors and dims their activity.
Impressively, when diseased mice that received the drug, they - for the first time - became able to better their scores on successive coordination tests.
And, though they never reached the same level of nimbleness as healthy mice did, they were fierce candidates for the title of "most improved players." Over the course of the testing, they achieved nearly the same degree of improvement in their before and after coordination scores as healthy mice did. In fact, almost second for second.
"It seems we may have corrected some sort of motor learning deficit in the diseased mice," Pearce said.
While optimistic about these findings, Pearce stressed the importance of reminding affected families that this work is preliminary.
"Much research is yet needed," Pearce said. "The prospect of offering this sort of investigational medicine to affected children is still years out."
Still, he is further encouraged that a drug called Talampanel - very similar to the blocking compound used by his team in Rochester - is currently in phase II clinical trials for treating epileptic seizures.
Unlike most anticonvulsants, which typically target cells known as NMDA receptors, Talampanel works by partially blocking AMPA receptors.
"This orally active new drug would be an obvious choice for clinical trials with juvenile Batten disease patients," Pearce said. "Especially since they routinely suffer seizures, as well."
Though only 150 children in the United States suffer Batten disease, Pearce is hopeful that this research will also likely also inform research efforts for a dozen or so of its cousins - other uncommon genetic diseases, each characterized by a glitch with the cell's toxin-ridding mechanisms, the lysosomes.
Some of these lysosomal-storage diseases, as they're called, include Krabbe disease (to which Buffalo Bills quarterback Jim Kelly lost his son, Hunter, in 2005), Tay-Sachs and metchromatic leukodystrophy.
"Our research might indeed open doors for learning how other neurological disorders might benefit from drugs that regulate AMPA receptors," Pearce said.
Co-author Attila KovГЎcs, Ph. D., assistant research professor in the Department of Biochemistry and Biophysics at the University of Rochester, contributed to this investigation, which was funded by National Institutes of Health and the Luke and Rachel Batten Foundation.
Source: Becky Jones
University of Rochester Medical Center
The study, highlighted in the January edition of Experimental Neurology, explains how investigators improved the motor skills of feeble mice that model the disease, helping them to better their scores on successive coordination tests.
"No treatment currently exists for these kids - nothing to halt the disease, or even to slow it down," said one of the study's authors, David Pearce, Ph.D., a nationally renowned Batten disease expert and biochemist at the University of Rochester. His team has published more than 50 studies on the disease's basic mechanisms.
"Since deterioration of motor skills is the rule - in fact, it's one of the primary symptoms in children with the disease - the idea that these functions might be able to be partially restored or improved is groundbreaking," Pearce said.
Last year, University of Rochester researchers discovered that, in mice with the disease, a set of the brain's receptor cells - known as the AMPA receptors - were unusually sensitive to glutamate, a neurotransmitter vital for learning and memory. These 'super-ticklish' receptors were located in the cerebellum, a brain region that plays a hefty role in sensory perception and motor control.
"For us, their abnormal activity made them key suspects in the brain dysfunction and neurological decline associated with the disease," Pearce said.
To test that, researchers administered a drug that partially blocks these receptors and dims their activity.
Impressively, when diseased mice that received the drug, they - for the first time - became able to better their scores on successive coordination tests.
And, though they never reached the same level of nimbleness as healthy mice did, they were fierce candidates for the title of "most improved players." Over the course of the testing, they achieved nearly the same degree of improvement in their before and after coordination scores as healthy mice did. In fact, almost second for second.
"It seems we may have corrected some sort of motor learning deficit in the diseased mice," Pearce said.
While optimistic about these findings, Pearce stressed the importance of reminding affected families that this work is preliminary.
"Much research is yet needed," Pearce said. "The prospect of offering this sort of investigational medicine to affected children is still years out."
Still, he is further encouraged that a drug called Talampanel - very similar to the blocking compound used by his team in Rochester - is currently in phase II clinical trials for treating epileptic seizures.
Unlike most anticonvulsants, which typically target cells known as NMDA receptors, Talampanel works by partially blocking AMPA receptors.
"This orally active new drug would be an obvious choice for clinical trials with juvenile Batten disease patients," Pearce said. "Especially since they routinely suffer seizures, as well."
Though only 150 children in the United States suffer Batten disease, Pearce is hopeful that this research will also likely also inform research efforts for a dozen or so of its cousins - other uncommon genetic diseases, each characterized by a glitch with the cell's toxin-ridding mechanisms, the lysosomes.
Some of these lysosomal-storage diseases, as they're called, include Krabbe disease (to which Buffalo Bills quarterback Jim Kelly lost his son, Hunter, in 2005), Tay-Sachs and metchromatic leukodystrophy.
"Our research might indeed open doors for learning how other neurological disorders might benefit from drugs that regulate AMPA receptors," Pearce said.
Co-author Attila KovГЎcs, Ph. D., assistant research professor in the Department of Biochemistry and Biophysics at the University of Rochester, contributed to this investigation, which was funded by National Institutes of Health and the Luke and Rachel Batten Foundation.
Source: Becky Jones
University of Rochester Medical Center
One Side-Effect Of An Anti-Cancer Drug Counteracted By Carbon Monoxide
Doxorubicin (DOX) is a red-colored anticancer drug that carries serious side effects for the heart, including cardiac muscle deterioration (cardiomyopathy) and scar tissue accumulation in the heart (fibrosis). These cardio-toxic effects are due to inhibition by DOX of mitochondrial biogenesis, a term used to describe cellular energy generation. In a new study by Claude Piantadosi and his colleagues at Duke University Medical Center, mitochondrial biogenesis was recovered in DOX-treated rodents by either inhalation of carbon monoxide (CO) or overexpression of the protein HO-1.
Mitochondrial biogenesis is known to depend on the presence of CO and HO, which promote energy production and defend the cell from injury. In mice treated with DOX, mitochondrial biogenesis in the heart was suppressed, resulting in heart cell death, thinning and dilation of the heart wall, and fibrosis. However, periodic inhalation of CO by DOX-treated mice restored mitochondrial biogenesis and averted cardiomyopathy. Likewise, overexpression of HO-1 in DOX-treated rat cardiac cells reduced mitochondrial DNA damage and subsequent cell death. The authors therefore suggested that protecting mitochondrial biogenesis in cancer patients treated with DOX might reduce the cardio-toxic side effects of the drug.
TITLE: The CO/HO system reverses inhibition of mitochondrial biogenesis and prevents murine doxorubicin cardiomyopathy
Author:
Claude A. Piantadosi
Duke University Medical Center, Durham, North Carolina, USA
Source: Karen Honey
Journal of Clinical Investigation
Mitochondrial biogenesis is known to depend on the presence of CO and HO, which promote energy production and defend the cell from injury. In mice treated with DOX, mitochondrial biogenesis in the heart was suppressed, resulting in heart cell death, thinning and dilation of the heart wall, and fibrosis. However, periodic inhalation of CO by DOX-treated mice restored mitochondrial biogenesis and averted cardiomyopathy. Likewise, overexpression of HO-1 in DOX-treated rat cardiac cells reduced mitochondrial DNA damage and subsequent cell death. The authors therefore suggested that protecting mitochondrial biogenesis in cancer patients treated with DOX might reduce the cardio-toxic side effects of the drug.
TITLE: The CO/HO system reverses inhibition of mitochondrial biogenesis and prevents murine doxorubicin cardiomyopathy
Author:
Claude A. Piantadosi
Duke University Medical Center, Durham, North Carolina, USA
Source: Karen Honey
Journal of Clinical Investigation
Symyx Showcases Research Services For Refining At 14th International Congress On Catalysis
Symyx Technologies, Inc. (NASDAQ: SMMX) announced, at the opening of the 14th Annual International Congress of Catalysis, the expansion of Symyx Research to include Refining R&D services. Symyx is showcasing its capabilities at the International Congress on Catalysis in Seoul, Korea, from July 14 to 18, 2008. Symyx Research for Refining provides companies with small scope, flexible service projects where clients pay per experiment, allowing scientists to access capability when and where they need it. The company's expertise is based on more than 10 years of catalyst development experience throughout the petrochemical and chemical industries,
"Refiners around the world are facing increasing environmental regulations, decreasing margins, and lower-quality feedstocks. It is critically important for chemists and researchers in the refining industry to develop and evaluate new catalysts to address these challenges," said Richard Boehner, president of Symyx Research. "Refining companies have catalyst experts. Symyx Research for Refining provides a means for these scientists to access results for experiments in experimental spaces they define."
Symyx Research for Refining gives companies access to Symyx's installed base of high-throughput experimentation technology and analytics as well as expert staff to synthesize and screen new catalyst libraries or screen client-provided catalysts for catalytic performance. This flexible, fee-for-service model allows the client to define experiment sets, own the scientific IP and pay no royalties. Infrastructure available through Symyx Research for Refining includes catalyst research and development capabilities for naphtha hydrodesulfurization, diesel hydrodesulfurization (& HDN), reforming, VGO hydrotreating, hydrocracking, lubes hydrotreating and alkylation.
With Symyx Research for Refining, the world's leaders in refining technology can reduce the number of pilot plant runs required for catalyst development by executing lab scale 'pilot plant representative' studies to identify catalysts and conditions that yield greater probabilities of success. In addition, proprietary fixed-bed reactor technology for gas phase reactions and trickle-bed reactor technology for high conversion studies gives companies representative pilot plant data without investing in additional infrastructure.
"Clients can now access pilot plant quality data from laboratory reactors, using real feedstocks," said Sam Bergh, Vice President of Engineering, Symyx Technologies, Inc. "This enables researchers to select catalysts with the greatest probability of success without having to perform numerous costly and time-consuming pilot plant runs on each candidate. Symyx Research provides not only a service to synthesize catalyst libraries but also to screen those catalysts in only a few months."
Scientists from Symyx are available to discuss Research for Refining capabilities at the International Congress on Catalysis in Seoul, Korea, July 14-18, 2008 at Booth #22-23. For more information, visit: symyx.
About Symyx
Symyx Technologies, Inc. is the scientific R&D integration partner to companies in the life sciences, chemicals, energy, electronics and consumer products industries. With scientific R&D under tremendous economic and technical pressure, Symyx helps companies reduce R&D risk and enhance R&D productivity to help them bring more and better products to market quickly and cost-effectively. Symyx's integrated technology platform combines electronic laboratory notebooks, content, laboratory logistics and analysis available from Symyx Software, software-driven integrated workflows available from Symyx Tools and collaborative research and directed services from Symyx Research to support the entire R&D process. Information about Symyx, including reports and other information filed by Symyx with the Securities and Exchange Commission, is available at symyx.
Symyx is a registered trademark of Symyx Technologies, Inc. All rights reserved. All other trademarks mentioned in this document are the property of their respective owners.
Symyx Technologies, Inc.
"Refiners around the world are facing increasing environmental regulations, decreasing margins, and lower-quality feedstocks. It is critically important for chemists and researchers in the refining industry to develop and evaluate new catalysts to address these challenges," said Richard Boehner, president of Symyx Research. "Refining companies have catalyst experts. Symyx Research for Refining provides a means for these scientists to access results for experiments in experimental spaces they define."
Symyx Research for Refining gives companies access to Symyx's installed base of high-throughput experimentation technology and analytics as well as expert staff to synthesize and screen new catalyst libraries or screen client-provided catalysts for catalytic performance. This flexible, fee-for-service model allows the client to define experiment sets, own the scientific IP and pay no royalties. Infrastructure available through Symyx Research for Refining includes catalyst research and development capabilities for naphtha hydrodesulfurization, diesel hydrodesulfurization (& HDN), reforming, VGO hydrotreating, hydrocracking, lubes hydrotreating and alkylation.
With Symyx Research for Refining, the world's leaders in refining technology can reduce the number of pilot plant runs required for catalyst development by executing lab scale 'pilot plant representative' studies to identify catalysts and conditions that yield greater probabilities of success. In addition, proprietary fixed-bed reactor technology for gas phase reactions and trickle-bed reactor technology for high conversion studies gives companies representative pilot plant data without investing in additional infrastructure.
"Clients can now access pilot plant quality data from laboratory reactors, using real feedstocks," said Sam Bergh, Vice President of Engineering, Symyx Technologies, Inc. "This enables researchers to select catalysts with the greatest probability of success without having to perform numerous costly and time-consuming pilot plant runs on each candidate. Symyx Research provides not only a service to synthesize catalyst libraries but also to screen those catalysts in only a few months."
Scientists from Symyx are available to discuss Research for Refining capabilities at the International Congress on Catalysis in Seoul, Korea, July 14-18, 2008 at Booth #22-23. For more information, visit: symyx.
About Symyx
Symyx Technologies, Inc. is the scientific R&D integration partner to companies in the life sciences, chemicals, energy, electronics and consumer products industries. With scientific R&D under tremendous economic and technical pressure, Symyx helps companies reduce R&D risk and enhance R&D productivity to help them bring more and better products to market quickly and cost-effectively. Symyx's integrated technology platform combines electronic laboratory notebooks, content, laboratory logistics and analysis available from Symyx Software, software-driven integrated workflows available from Symyx Tools and collaborative research and directed services from Symyx Research to support the entire R&D process. Information about Symyx, including reports and other information filed by Symyx with the Securities and Exchange Commission, is available at symyx.
Symyx is a registered trademark of Symyx Technologies, Inc. All rights reserved. All other trademarks mentioned in this document are the property of their respective owners.
Symyx Technologies, Inc.
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