May 13, 2007, 10:03 PM CT

Agent Protects Cells From Lethal Effects Of Radiation

Using this agent in mice, the researchers observed that the therapy helped shield rapidly dividing cells that are most vulnerable to radiation-induced death, providing proof in principle that it is possible to fend off radiation damage, as per a research studyreported in the recent issue of Biochemical and Biophysical Research Communications.

Current therapys for severe radiation exposure, also called acute radiation syndrome, are limited to drugs that boost the production of blood cells and platelets, but this approach is futile if underlying stem cells are also killed off. Moreover, there are no available therapys that can be given after exposure to limit damage to cells.

"We are using an entirely different approach," says Clayton Hunt, Ph.D., of the Department of Radiation Oncology. "Rather than ramp up the production of blood cells, we are trying to prevent radiation-induced cell death from occurring in the first place."

The scientists developed the agent by attaching a portion of the Bcl-xL protein already known to block cell death - a snippet called BH4 - to the HIV protein TAT, which can deftly carry other molecules into cells. They gave the agent intravenously to mice exposed to 5 Grays of radiation. In humans, this level of exposure would cause a sharp drop in blood cells, leaving individuals with an increased risk of infection and bleeding......... Posted by: Jessica      Read more         Source

May 10, 2007, 5:36 AM CT

the Structural Variations in Human Genetics

major new effort to uncover the medium- and large-scale genetic differences between humans may soon reveal DNA sequences that contribute to a wide range of diseases, as per a paper by Howard Hughes Medical Institute investigator Evan Eichler and 17 colleagues reported in the May 10, 2007, Nature. The undertaking will help scientists identify structural variations in DNA sequences, which Eichler says amount to as much as five to ten percent of the human genome.

Past studies of human genetic differences commonly have focused on the individual "letters" or bases of a DNA sequence. But the genetic differences between humans amount to more than simple spelling errors. "Structural changes - insertions, duplications, deletions, and inversions of DNA - are extremely common in the human population," says Eichler. "In fact, more bases are involved in structural changes in the genome than are involved in single-base-pair changes."

In some cases, individual genes appear in multiple copies because of duplications of DNA segments. In other cases, segments of DNA appear in some people but not others, which means that the "reference" human genome produced by the Human Genome Project is incomplete. "We're finding new sequence in the human genome that is not in the reference sequence," Eichler says......... Posted by: Rose      Read more         Source

May 9, 2007, 11:24 PM CT

genetic 'shut down' trigger in healthy immune cells

A fundamental genetic mechanism that shuts down an important gene in healthy immune system cells has been discovered that could one day lead to new therapies against infections, leukemia and other cancers. Results of a University of Pittsburgh School of Medicine study on the mechanism, called a somatic stop-codon mutation, are being reported today in the online journal PLoS ONE, published by the Public Library of Science.

"This kind of loss-of-function mutation can be very dangerous, and it is the first such mutation that has been identified in normal immune cells in blood," said Bora E. Baysal, M.D., Ph.D., assistant professor of obstetrics, gynecology and reproductive sciences at the University of Pittsburgh School of Medicine. "We did control experiments for two years to make sure it was real and not a technical error".

Dr. Baysal and colleagues tested 180 samples, including blood from healthy individuals and other material from those with childhood leukemia, looking at specific portions of DNA in immune cells known as monocytes, natural killer cells and lymphocytes. These cells are key to the bodys immune response against infection and disease. The researchers found somatic stop-codon mutations in an average of 5.8 percent of crucial portions of genetic material that deliver instructions from DNA, called messenger RNA, in normal blood samples and in a quarter of leukemia samples......... Posted by: Rose      Read more         Source

May 9, 2007, 11:10 PM CT

DNA linked to autistic spectrum disorders

Using an innovative statistical approach, a research team from Washington University School of Medicine in St. Louis and the University of California, Los Angeles, has identified two regions of DNA associated with autism. They found the suspicious DNA with a much smaller sample of people than has been used traditionally in searches for autism genes.

Autism a disorder that involves social deficits, language problems and repetitive, stereotyped behaviors affects around one in 1,000 children. And the combined occurence rate of autism spectrum disorders, which include Asperger syndrome and pervasive developmental disorder, brings the total number of affected children to one in every 150 births. Boys are affected three to four times more often than girls.

There's clearly a genetic component to autism, as per John N. Constantino, M.D., associate professor of psychiatry and pediatrics at Washington University School of Medicine and a co-principal investigator on this latest study. If one child in a family is autistic, there's a 10 percent chance a sibling also will have autism. Past research has isolated a few regions of DNA associated with autism, but very few of those studies have been replicated, so no specific autism genes have yet been identified.

"Those older studies used what's called an 'affected sib pair' design that looks for genetic markers in siblings with autism," says Constantino. "That approach has worked well for single-gene disorders, but autism is a complex disease that may involve a number of genes that each make very small contributions. When that's the case, it's harder to find genetic markers"......... Posted by: Rose      Read more         Source

May 7, 2007, 10:53 PM CT

The Healthy Immigrant Effect

New immigrants to Western nations are believed to experience fewer chronic health problems (e.g., diabetes, hypertension and heart disease) than long-time residents of those countries. Dr. Joel Ray and coauthors tested whether this "healthy immigrant effect" extends to complications during pregnancy.

In the Recent Immigrant Pregnancy and Perinatal Long-term Evaluation Study (RIPPLES), Ray and his colleagues examined the occurence rate of maternal placental syndrome defined as a diagnosis of pre-eclampsia or eclampsia (also called toxemia of pregnancy), placental abruption (a premature separation of the placenta from the uterus) or placental infarction (sudden blockage of the blood supply to the placenta) among more than 795 000 women who had a first documented delivery in Ontario between 1995 and 2005. They observed that the risk of maternal placental syndrome was lowest among the most recent immigrants to Ontario (women who immigrated within 3 months before delivery) and highest among those who had been living in the province for 5 or more years before delivery. The more months which have passed since immigration, the higher the risk of placental complications. Health factors such as high blood pressure, obesity and tobacco dependence all of which can affect the health of the placenta were noted to increase in incidence with length of residence in Ontario......... Posted by: Rose      Read more         Source

April 30, 2007, 6:39 PM CT

Major Advance In Structural Biology

Scientists from Baylor College of Medicine (BCM) and Rice University have discovered a new way to analyze the moving parts of large proteins a breakthrough that will make it easier for structural biologists to classify and scrutinize the active sites of proteins implicated in cancer and other diseases.

The breakthrough research will appear online this week and in an upcoming edition of the Proceedings of the National Academy of Science (PNAS). In involves a new mathematical algorithm that narrows down all the possible ways a protein might flex and bend. The math is used in conjunction with information captured via X-ray crystallography, a technique in which protein crystals are bombarded with X-rays, producing a diffraction pattern that reveals the precise three-dimensional arrangement of every atom in the protein.

"Increasingly, our discipline is faced with deciphering the structure of large, complex proteins in which some parts are constantly moving, even when the protein is locked in a crystal form," said lead researcher Jianpeng Ma, who holds joint appointments at both BCM and Rice. "We expect our method to be particularly useful in refining very large and flexible supramolecular complexes with limited diffraction data".

Nobel laureate William Lipscomb of Harvard University, one of the founding fathers of protein crystallography in the North America, said, "This recent success in X-ray crystallographic refinement is revolutionary for the field of structure biology in terms of improving large and flexible complex structures that are becoming far more abundant nowadays. It is one of the largest technical leap-forwards in X-ray refinement in the last two decades. It will fundamentally change the way people do structural refinement for large and flexible complexes"......... Posted by: Rose      Read more         Source

April 25, 2007, 9:14 PM CT

computer modeling system for organ allocation

The International Society for Heart and Lung Transplantation (ISHLT) announces evaluation of a new mathematical modeling system for lung allocation in the United States and the ethical issues surrounding organ allocation facing patients awaiting transplants. Both will be discussed at its 27th Annual Meeting and Scientific Sessions, today in Satellite Symposium 9, Continued Evaluation of Heart and Lung Allocation Using Evidence Based Research.

Worldwide, patients in need of transplant are placed on a waiting list for donor lungs, using a wide variety of systems. In the United States, patients are currently assessed for organ allocation based on a new mathematical modeling system, in which patient information is entered into a computer database and donors are then matched with recipients based on specific characteristics. Two of the most important criteria are the chance of survival without the transplant and the projected condition of the patient post transplant. The computer program then generates a list of patients that are ranked as per preset organ allocation policies. Once selected, there are many tests that must be performed in order to evaluate whether the recipient may in fact receive the organ. Taking into consideration the novelty of the system, an international representation of ISHLT membership will convene to evaluate this new modeling system to determine its effectiveness and Leah Edwards, Ph.D., United Network for Organ Sharing, will present How is the Lung Allocation Score Working in the US? during the Symposium......... Posted by: Rose      Read more         Source

April 24, 2007, 10:24 PM CT

Treatment of Damaging Protein Plaques

When protein plaque builds up in the blood, it can result in serious diseases such as heart disease and Alzheimer's. Cyclooxygenase (COX) inhibitors, a class of drugs under investigation for the treatment of one cause of plaque build-up, also exhibit negative side effects.

Researchers in the International Institute of Nano and Molecular Medicine at the University of Missouri-Columbia are studying the possible use of carboranes, which are clusters of boron and carbon atoms, to prevent such side effects. These boron-rich clusters are substituted for carbon-based benzene rings commonly found in pharmaceuticals of all types, including COX inhibitors, which give unwanted side effects.

COX activity is seen in common nonsteroidal anti-inflammatory drugs like aspirin and ibuprofen. However, prolonged use of COX inhibitors can result in a variety of negative side effects, such as possible digestive and liver problems. Some COX inhibitors have recently been pulled from the market due to an increased risk of heart complications.

The protein transythyretin acts as a shuttle to transport thyroxine, a hormone, throughout the body. As the least important of the three blood proteins that carry thyroxine, transthyretin also has a tendency to fall apart and form tough, insoluble plaques, sometimes causing injury to delicate tissues. Certain people are genetically more likely to have the proteins fall apart, increasing the risks. Investigators have found that in laboratory experiments, certain COX inhibitors help stabilize the structure of transthyretin protein, and therefore prevent harmful plaque formation......... Posted by: Rose      Read more         Source

April 23, 2007, 11:01 PM CT

A steady, high-fat diet is bad

So much for the adage, All things in moderation. Researchers at the University of Calgary have found that people who consume a single, high-fat meal are more prone to suffer the physical consequences of stress than those who eat a low-fat meal.

Published this month in the Journal of Nutrition, the study looked at the stress responses of two groups of students: one group consumed a fast-food breakfast from McDonalds, the other ate dry cereal with skim milk, cereal bars and non-fat yogurt.

"Whats really shocking is that this is just one meal," says Dr Tavis Campbell, a specialist in behavioural medicine and senior author of the study.

"Its been well documented that a high-fat diet leads to artherosclerosis and high blood pressure, and that exaggerated and prolonged cardiovascular responses to stress are associated with high blood pressure in the future. So when we learn that even a single, high-fat meal can make you more reactive to stress, its cause for concern because it suggests a new and damaging way that a high-fat diet affects cardiovascular function." .

In the study, 30 healthy young adults fasted the night before, then consumed either a high- or low-fat breakfast. Both meals had the same number of calories and the low-fat breakfast included supplements to balance it for sodium and potassium......... Posted by: Rose      Read more         Source

April 23, 2007, 10:37 PM CT

Chronically ill people used Qigong

Oriental therapies can help chronically ill people stay strong and reduce stress levels during epidemics, as per research in the recent issue of Journal of Clinical Nursing.

Scientists have shown that people who practiced the Oriental art of Qigong which combines gentle exercise with breathing techniques, meditation and visualisation reaped considerable benefits during the SARS outbreak in Hong Kong.

It also helped them to cope with the stigmatisation and discrimination that developed against chronically ill people during the crisis, as they were seen as a high risk group with a much greater chance of being infected by, and dying from, the disease.

"We were already studying the health benefits of this very popular treatment when SARS severe acute respiratory syndrome hit Hong Kong" explains lead author Judy Yuen-man Siu, who carried out the research in the Department of Anthropology at The Chinese University of Hong Kong.

"Chronically ill people, like the ones in our study, were especially at risk during the outbreak, which affected 1,755 people in Hong Kong and killed 299. Because our study had already been established, we were able to extend it to monitor how people harnessed Qigong, which was used by a number of Hong Kong people during the crisis"......... Posted by: Rose      Read more         Source