July 5, 2011, 8:12 PM CT
Lifestyle, diet can significantly influence course of macular degeneration
Eating a diet high in vitamin D, as well as the nutrients betaine and methionine, might help reduce the risk of macular degeneration, as per new research conducted by Tufts Medical Center scientists. Their study of identical twins from the US World War II Twin Registry also observed that the more a person smoked, the higher their risk of developing macular degeneration. The study, "Smoking, Dietary Betaine, Methionine, and Vitamin D in Monozygotic Twins with Discordant Macular Degeneration: Epigenetic Implications" reported in the journal Ophthalmology on July 1, is the first to look at identical twin pairs in which one twin had early age-related macular degeneration (AMD), and the other had late stage AMD.
AMD is highly heritable, with genetic factors determining up to 71 percent of the disease's severity as determined by a prior study of this twin registry by this same research team. By examining identical twins with the same genes but whose disease was at different stages, scientists were able to identify environmental and behavioral factors that may contribute to severity of the disease. "We wanted to know why, if they have the same genes, do they have different stages of the disease?'' said lead researcher Johanna M. Seddon, MD, ScM, Director of the Epidemiology and Genetics Service, Tufts Medical Center, and Professor of Ophthalmology, Tufts Universtity School of Medicine.........
Posted by: Mike Read more Source
June 22, 2011, 10:52 PM CT
Link Between Parkinson's and Pesticides
Zezong Gu, right, MD, PhD, assistant professor of pathology and anatomical sciences at MU, and Fajun Meng, an MU visiting scholar, examine a model of parkin clusters. Their research yields new details about how parkin proteins and pesticides contribute to Parkinson's disease. After Alzheimer's disease, Parkinson's disease is the most common neurodegenerative disorder.
In a new article reported in the journal Molecular Neurodegeneration, scientists at the University of Missouri School of Medicine take some of the first steps toward unraveling the molecular dysfunction that occurs when proteins are exposed to environmental toxins. Their discovery helps further explain recent NIH findings that demonstrate the link between Parkinson's disease and two particular pesticides - rotenone and paraquat.
"Fewer than 5 percent of Parkinson's cases are attributed to genetics, but more than 95 percent of cases have unknown causes," said Zezong Gu, MD, PhD, assistant professor of pathology and anatomical sciences. "This study provides the evidence that oxidative stress, possibly due to sustained exposure to environmental toxins, may serve as a primary cause of Parkinson's. This helps us begin to unveil why a number of people, such as farmers exposed to pesticides, have an increased occurence rate of the disease."
Researchers previously understood that Parkinson's is linked to oxidative stress, which is when electronically unstable atoms or molecules damage cells. The MU study yields more specific information about how oxidative stress causes parkin, a protein responsible for regulating other proteins, to malfunction.
These findings come as the result of collaborative research conducted by Gu and the paper's primary author, Fanjun Meng, an MU visiting scholar from the Chinese Academy of Sciences Beijing Institute of Genomics, as well as colleagues at the Sanford-Burnham Medical Research Institute and the University of California at San Diego. The article also represents the first published work from scientists at the new MU Center for Translational Neuroscience.........
Posted by: Daniel Read more Source
June 21, 2011, 11:45 PM CT
Marriage improves odds of surviving colon cancer
A newly released study shows that being married boosts survival odds for both men and women with colon cancer at every stage of the disease.
Married patients had a 14 percent lower risk of death as per scientists at Penn State's College of Medicine and Brigham Young University. That estimate is based on analysis of 127,753 patient records.
Similar to studies of other types of cancers, the scientists did find that married people were diagnosed at earlier stages of colon cancer and sought more aggressive therapy. The scientists took those and other factors into account before calculating the benefit of marriage on survival odds.
"Controlling for the stage that the cancer was detected is key," said Sven Wilson, a study coauthor and professor at Brigham Young University. "Without that, it's hard to know whether the analysis is just picking up a diagnosis effect".
Colon cancer is the fourth most common type of cancer in the United States for both men and women. Curiously, the marriage benefit seen in the newly released study was nearly identical for both men and women.
So what's driving the different survival rates? Marriage is a self-selected group, and Wilson is careful to note that the selection process makes it difficult to sort out the root cause. One intuitive idea is that spouses serve as an important informal caregiver during a critical time, and that extra support may translate into better disease management and, hence, better outcomes.........
Posted by: Sue Read more Source
June 21, 2011, 11:36 PM CT
Stem cell model offers clues to cause of inherited ALS
This image shows motor neurons (green) derived from ALS induced pluripotent stem cells forming neuromuscular junctions (red).
Credit: Image courtesy of Alysson Muotri, UCSD.
An international team of researchers led by scientists at the University of California, San Diego School of Medicine have used induced pluripotent stem cells (iPSCs) derived from patients with amyotrophic lateral sclerosis (ALS) to reveal for the first time how reduced levels of a specific protein may play a central role in causing at least one inherited form of the disease.
The work, reported in the June 2011 online issue of the journal Human Molecular Genetics
, could help researchers overcome a major hurdle in the study and therapy of ALS, an incurable neuromuscular disorder also known as Lou Gehrig's disease. ALS is universally fatal, with a median age of onset of 55 years and survival of two to five years after symptoms appear. Past research efforts have long been stymied by difficulties in translating successful drug tests in animal models of ALS to humans.
"There is an urgent need for ALS human models that can be translated into clinical trials to verify therapeutic targets in the human genetic background," said Alysson R. Muotri, PhD, assistant professor in the UCSD Departments of Pediatrics and Cellular and Molecular Medicine, and one of the study's senior authors. "Rodents have been used in the past and still have a critical impact in unveiling the complexity of ALS, but the vast majority of drugs that have demonstrated efficacy in rodent models have not done the same in preclinical and clinical human trials".........
Posted by: Daniel Read more Source
June 13, 2011, 7:58 AM CT
We are all mutants
Each one of us receives approximately 60 new mutations in our genome from our parents.
This striking value is published in the first-ever direct measure of new mutations coming from mother and father in whole human genomes published recently.
For the first time, scientists have been able to answer the questions: how a number of new mutations does a child have and did most of them come from mum or dad? The scientists measured directly the numbers of mutations in two families, using whole genome sequences from the 1000 Genomes Project. The results also reveal that human genomes, like all genomes, are changed by the forces of mutation: our DNA is altered by differences in its code from that of our parents. Mutations that occur in sperm or egg cells will be 'new' mutations not seen in our parents.
Eventhough most of our variety comes from reshuffling of genes from our parents, new mutations are the ultimate source from which new variation is drawn. Finding new mutations is extremely technically challenging as, on average, only 1 in every 100 million letters of DNA is altered each generation.
Prior measures of the mutation rate in humans has either averaged across both sexes or measured over several generations. There has been no measure of the new mutations passed from a specific parent to a child among multiple individuals or families.........
Posted by: Scott Read more Source
June 13, 2011, 7:55 AM CT
Bariatric surgery among older
The use of bariatric surgery among older, severely obese patients was not linked to a decreased risk of death, as per a research studyin the June 15 issue of JAMA
This study is being released early online to coincide with its presentation at the AcademyHealth Annual Research Meeting.
"Obesity incidence has stabilized after decades of rapid increases, whereas the prevalence of patients with a body mass index [BMI] greater than 35 increased 39 percent between 2000 and 2005, the prevalence of severe obesity (BMI greater than 40) increased 50 percent, and the prevalence of superobesity (BMI greater than 50) increased 75 percent. Obesity is difficult to treat, and bariatric surgery is the most effective means to induce weight loss for the severely obese. Consequently, obesity surgery rates rapidly increased in tandem," as per background information in the article. "To date, no study to our knowledge has examined the long-term survival of high-risk patients who underwent bariatric surgery".
Matthew L. Maciejewski, Ph.D., of the Durham VA Medical Center, Durham, N.C., and his colleagues conducted a study to determine whether bariatric surgery is linked to reduced mortality among predominantly older male high-risk patients at Veterans Affairs medical centers. Mortality was examined for 850 veterans who had bariatric surgery in January 2000 to December 2006 (average age 49.5 years; average BMI, 47.4) and 41,244 nonsurgical controls (average age 54.7 years; average BMI 42.0) from the same 12 Veteran Integrated Service Networks; the follow-up was through December 2008.........
Posted by: JoAnn Read more Source
June 13, 2011, 7:51 AM CT
Finding genetic mistakes that fuel cancer
A dramatically better computer tool for finding the genetic missteps that fuel cancer has been developed by St. Jude Children's Research Hospital � Washington University Pediatric Cancer Genome Project investigators. Scientists are using the new algorithm to help identify the chromosomal rearrangements and DNA insertions or deletions unique to cancer.
The new computational method is known as CREST, short for Clipping Reveals Structure. Using CREST, scientists identified 89 new structural differences in the cancer genomes of five St. Jude patients with a subtype of acute lymphoblastic leukemia (ALL) known as T-lineage ALL. CREST revealed complex chromosomal rearrangements, including one that involved four chromosomes. Investigators also used the tool to find 50 new variations in melanoma cells. Melanoma is the most serious form of skin cancer. The study appears in the June 12 advance online edition of the scientific journal Nature Methods.
"CREST is significantly more accurate and sensitive than existing methods of finding structural variations in next-generation sequencing data. It finds differences between a patient's normal and cancer genomes other tools cannot find," said Jinghui Zhang, Ph.D., an associate member of the St. Jude Department of Computational Biology. She is the study's senior author. "Similar tools miss up to 60 to 70 percent of these structural rearrangements in tumors. CREST ensures that researchers will be able to find important structural variations that play critical roles in tumor formation".........
Posted by: Janet Read more Source
June 13, 2011, 7:50 AM CT
Early exposure to pets does not increase children's risk of allergies
A newly released study reported in the journal Clinical & Experimental Allergy
reveals that keeping a dog or cat in the home does not increase children's risk of becoming allergic to the pets.
Parents of young children frequently want to know whether keeping a dog or cat in their home will increase the risk of their children becoming allergic to their pets.
Led by Ganesa Wegienka, MS, PhD, of the Department of Public Health Sciences, Henry Ford Hospital, scientists followed a group of children from birth until they reached adulthood. Periodic contact was made with the parents and the children to collect information about exposure to cats and dogs.
At age 18 years, 565 study participants supplied blood samples to the researchers, who measured antibodies to dog and cat allergens in the samples.
Results observed that being exposed to the specific animal in the first year of life was the most important exposure period, and the exposure appeared protective in some groups.
Young men whose families had kept an indoor dog during their first year of life had about half the risk of becoming sensitized to dogs in comparison to those whose families did not keep a dog in the first year of life.
Both men and women were about half as likely to be sensitized to cats if they had lived with a cat in the first year of life, in comparison to those who did not live with cats.........
Posted by: JoAnn Read more Source
June 13, 2011, 7:47 AM CT
Head and neck cancer and second round of treatment
A newly released study has determined predictors that can better identify patients who will benefit from a potentially toxic second course of therapy, which offers a small but real chance of cure in select patients with head and neck cancer. Published early online in Cancer
, a peer-evaluated journal of the American Cancer Society, the findings could help guide therapy decisions for head and neck cancer patients.
Radiation is often used to treat patients with head and neck cancer. If their cancer reappears, they have limited therapy choices: chemotherapy is not curative, and surgery can be curative but is often not possible. Chemotherapy and a second course of radiation have previously been shown to be another option. Joseph Salama, MD, formerly of the University of Chicago, and colleagues conducted an analysis of previous studies to determine how patients tolerate this second round of therapy and which patients benefit the most from it.
The researchers analyzed data from 166 patients with head and neck cancer who received a first round of radiation followed by a second round plus chemotherapy because their cancer recurred or they developed a new tumor. The second course of therapy could cure approximately 25 percent of patients at two years, but it was quite toxic. (Some patients lost the ability to speak or swallow. In addition, approximately 20 percent of patients died from therapy-related complications.)........
Posted by: Janet Read more Source
June 13, 2011, 7:44 AM CT
Routine screening for autism not needed
Proposals recommending routine screening of all children for autism gets a thumbs down from scientists at McMaster University.
In a study in the online edition of the journal Pediatrics
, the scientists say there is "not enough sound evidence to support the implementation of a routine population-based screening program for autism".
Not only are there no good screening tools or effective therapys but there is no evidence yet that routine screening does more good than harm, said Dr. Jan Willem Gorter, a researcher in McMaster's CanChild Centre for Childhood Disability Research and associate professor of pediatrics.
Contrary to the McMaster researchers' findings, the American Academy of Pediatrics recently recommended that screening for autism be incorporated into routine practice, such as a child's regular doctor check-up, regardless of whether a concern has been raised by the parents.
Autism, or the autism spectrum disorders (ASDs), is a group of serious neurodevelopmental disorder with major, life-altering implications. Its symptoms include differences and disabilities in a number of areas, including social, communication skills, fine and gross motor skills, and sometimes intellectual skills.
During the past three decades, the prevalence of autism has risen dramatically to 11 cases per 1,000 school-aged children from 0.8 cases per 1,000. Reasons for this increase vary: improved detection, changes in diagnosing the disorder or an actual increase. The disorder is more common in males with a 4:1 male-to-female ratio.........
Posted by: JoAnn Read more Source