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December 20, 2005
Expanding Mammography's Power
A team of researchers, including Bradley J. Lucier, has found that digitized mammograms, the X-ray cross sections of breast tissue that doctors use to search for cancer, are actually interpreted more accurately by radiologists once they have been "compressed" using techniques similar to those used to lessen the memory demand of images in digital cameras. Though compression strips away much of the original data, it still leaves intact those features that physicians need most to diagnose cancer effectively. Perhaps equally important, digitization could bring mammography to a number of outlying communities via mobile equipment and dial-up Internet connections.
"Any technique that improves the performance of radiologists is helpful, but this also means that mammograms can be taken in remote places that are underserved by the medical community," said Lucier, who is a professor of mathematics and computer science in Purdue's College of Science. "The mammograms can then be sent electronically to radiologists, who can read the digitized versions knowing they will do at least as well as the original mammograms".
The research paper will appear in today's (Dec. 20) issue of Radiology, the journal of the Radiological Society of North America. Lucier developed the file-compression method used in the study, which was run at the Moffitt Cancer Center at the University of South Florida in Tampa.
Discerning the potential seeds of cancer within the chaff of extraneous detail present in a mammogram requires the expert eye of a radiologist, who must pick out salient features at a number of different scales within the image. Clues can be very small clusters of tiny calcium deposits, each less than one-hundredth of an inch in diameter. Clues also can range up through the edges of medium-sized objects - which could be non-malignant cysts with smooth edges, for example, or malignant tumors with rough edges - up to large-scale patterns in tissue fiber.........
December 20, 2005
Genetic Testing Still Smart Choice
Citing concerns about the accuracy of preimplantation genetic diagnosis, the method a number of practitioners use to pick the healthiest embryos during IVF, UF scientists set out to study the procedure. Their work, described during a recent meeting of the American Society of Reproductive Medicine, reveals the technique is actually highly reliable. But because there is a slim chance a genetic abnormality can cause doctors to misdiagnose embryos, some concerns still need to be addressed, the scientists said.
Preimplantation genetic diagnosis has been used for more than a decade to screen embryos for hereditary diseases such as Down syndrome and other abnormalities. To do this, one cell from an eight-cell embryo is extracted and examined for chromosomal defects.
However, as a number of as half these embryos spawn cells with different genetic information as they divide, giving doctors an inaccurate idea of how the embryo will continue to develop, said Larissa Kovalinskaia, a UF research associate with the College of Medicine's IVF program. While a number of embryos with this abnormality - called chromosomal mosaicism - stop developing early, some go on to be born. Because these embryos' cells contain different sets of chromosomes, doctors cannot always accurately screen them for genetic diseases, Kovalinskaia said.
"As more data were coming out, saying that as a number of as 50 percent of (IVF) embryos were mosaic, we started worrying about the accuracy of preimplantation genetic diagnosis," she said. "When you take one cell, does it represent the entire embryo? What we've shown is that we can rely on PGD".........
December 20, 2005
Neighborhoods May Affect Asthma
While study findings showed worse health and poorer quality of life among people living in lower-income areas, they also showed poorer lung function among those living in suburbs, where people tended to own newer homes in less densely populated neighborhoods.
The study, conducted by scientists from the University of California, San Francisco, is published in the recent issue of the European Respiratory Journal.
The analysis did not pinpoint exposures that might be linked to these population effects, but most scientists believe water-damaged housing stock, proximity to high traffic flow, industrial pollution, and social environmental stress are key contributors to health problems in poorer neighborhoods. The study raises the possibility that more frequent household pet ownership may be one factor in lower lung function in suburban-related health exposures, eventhough larger backyards with more allergenic plants could be a contributor.
"Our research could be subtitled 'No Man is an Island,'" said Paul Blanc, MD, UCSF professor of occupational and environmental medicine and lead author of the study. "The study findings underscore that asthma is a complex problem that does not simply affect people in isolation."
"Even if individual risk factors such as poor access to medical care can be overcome, different communities have different asthma patterns, and strategies for prevention and therapy must take this into account," he said.
Blanc cites the need for studies to nail down the community-wide physical and social environmental factors that contribute to asthma and poorer respiratory health.........
December 20, 2005
Hormone Therapy Goes On Trial
Marcelle Cedars, MDScientists at UCSF Medical Center are about to embark on a study with a controversial theme: Despite its bad reputation at present, can hormone treatment (HT) after menopause protect women from heart disease.
"Heart disease is still the nation's leading killer of women, and we need to understand how the disease develops in women," said lead investigator Marcelle Cedars, MD, director of the Division of Reproductive Endocrinology in the UCSF Department of Obstetrics, Gynecology and Reproductive Sciences.
UCSF is one of eight centers nationwide participating in the Kronos Early Estrogen Prevention Study, known as KEEPS, which is being by coordinated by the Phoenix-based Kronos Longevity Research Institute.
UCSF is recruiting 90 healthy, recently menopausal women who have not had a hysterectomy, are six months to three years from their last menses, and are 42 to 58 years of age.
KEEPS is a randomized, placebo-controlled, double-blind trial of 720 women designed to provide prospective data on the risks and benefits of HT in women who have recently begun menopause. Of particular interest is the role of estrogen during menses as it relates to the progression of atherosclerosis (hardening of the arteries).
Previous to 2002, most studies suggested that HT reduced the risk of heart disease by 30 to 50 percent. But in July of that year, the widely published Women's Health Initiative (WHI) was halted by the National Institutes of Health when results showed no preventive benefit against heart disease in women who were a number of years past menopause. The WHI was a primary prevention trial of estrogen plus progestin hormone treatment in 16,608 postmenopausal women between the ages 50-79. It was the first randomized, placebo-controlled, double-blind trial of HT, and for this reason its results were believed to be nearly definitive, according to Cedars.........
December 20, 2005
Protein Responsible For Shaping The Nervous System
"We discovered that p63 is the major death-promoting protein for nerve cells during fetal and post-natal development," said Dr. David Kaplan, the paper's senior author, senior scientist at SickKids, professor of Molecular Genetics, Medical Genetics and Microbiology at U of T, Canada Research Chair in Cancer and Neuroscience, and co-team leader on the NeuroScience Canada Brain Repair Program grant with Dr. Freda Miller of SickKids. "Proteins such as p63 that regulate beneficial cell death processes during development may cause adverse affects later in life by making us more sensitive to injury and disease".
At birth, the nervous system has twice the number of nerve cells than needed. The body disposes of the excess cells by eliminating those that go to the wrong place or form weak or improper connections. If this process does not happen, the nervous system cannot function properly. The expression of the p63 protein guides the nervous system in disposing of the ineffective nerve cells. The protein is from the p53 family of tumour suppressor proteins that is mutated in a number of human cancers.
While p63 is involved in determining which nerve cells die, the research team also suspects that it determines whether nerve cells die when injured or in neurological and neurodegenerative diseases such as Alzheimer's and Parkinson's diseases.........
December 20, 2005
Genetics May Guide New Infertility Therapies
One in six couples is experiencing fertility problems worldwide, and people are asking why. This is a question of great medical, social and economic importance - one that cannot be answered until the process of fertilization is more fully understood.
A team led by Andrew Singson, an assistant professor and Pavan Kadandale, a graduate student in the Singson lab at the Waksman Institute of Microbiology at Rutgers, The State University of New Jersey, has taken a new and productive approach in this quest. The scientists found that in the absence of these two genes, the vital process of fertilization came to a halt. "What we learn in studying fertilization is not only important for this event, but also for the functioning of other cells in our bodies and for understanding a number of of those processes," Singson said.
Fertilization can be a paradigm for gaining insight into how cells interact over the life and development of multicellular organisms because it is one of the most basic of cell-cell interactions. The underlying cell biology is going to be universal with applications even in infectious diseases, such as AIDS, where the virus passes its genetic material to the cells it infects just as fertilization transmits sperm DNA to the egg, Singson explained.
Fertilization has primarily been studied in mammals or select marine invertebrates; but Singson and his group have instead turned to the lowly roundworm Caenorhabditis elegans (C. elegans), the first multicellular organism to have had its genome completely sequenced.........
December 20, 2005
Preventing Winter Sports Related Injuries
One of the most common winter related injuries is due to shoveling snow. "It is vigorous exercise and a big strain on the back that people don't appreciate," says Palmer. "The weight and position are really bad for two parts of your back. A disc could be compressed resulting in a pinched nerve. Also, the muscles in the lower back are small and easily strained".
Palmer suggests preventing problems with good positioning and exercise. When you lift 10 pounds close to your body it exerts 10 pounds of pressure on the back. If you lift that same 10 pounds away from your body, as people often do when shoveling, it is seven times heavier exerting 70 pounds of pressure on the back.
The best advice is don't do it. "Our bodies are not built to shovel snow," says Palmer. "Get a snowblower or pay the neighbor kid to do it for you".
If you insist on shoveling yourself, Palmer suggests you start exercising now. "You need to get in shape and build up those back muscles before the snow falls".
That advice holds true for winter sports as well. Exercising in cold weather places extra demands on the body. If you haven't exercised regularly in months, you are more likely to suffer an injury on the ski slopes or at the ice rink. Palmer, who is also a doctor committee member of the United States Ski and Snowboard Association, suggests paying special attention to muscles particular to your chosen sport.........
December 20, 2005
Blood test can accurately diagnose heart failure
"It is well understood that kidney disease reduces the usefulness of testing for both NT-proBNP and a related biomarker called BNP, and the conventional understanding was that NT-proBNP was the more affected of the two," says James Januzzi Jr., MD, of the MGH Cardiology Division, the paper's senior author. "However, while kidney disease did lead to higher values of NT-proBNP in our study, what really matters is clinical performance; and at optimal cut-points, no matter how hard we looked, we found the relationship between chronic kidney disease and the diagnostic accuracy of NT-proBNP was no different than that of BNP. Our findings thus directly contradict observations based on smaller, less characterized patient populations".
Congestive heart failure, which occurs when an impaired heart muscle cannot pump blood efficiently, is a growing health problem and major cause of cardiac death. The diagnosis of heart failure may be challenging because its symptoms can overlap those of other conditions. Missing a heart failure diagnosis can put patients at high risk of serious problems, including death, but overdiagnosis may lead patients to receive unnecessary therapy.
Published earlier this year, the PRIDE study showed NT-proBNP to be highly sensitive and specific for the diagnosis of acute heart failure in patients with shortness of breath and to strongly predict patient deaths. A major concern about the widespread use of the marker had been prior assertions that kidney disease - very common in patients with heart failure - might confound the results of NT-proBNP testing, since levels of the marker were higher among those with reduced renal function.........
December 20, 2005
Step Aside for Strep Throat Treatment
The most common medications used to treat the strep germ, the bug that causes millions of sore throats in U.S. children every year, simply aren't doing the job and aren't as effective as newer antibiotics known as cephalosporins. In results presented this weekend at a large infectious disease meeting, the annual Interscience Conference on Antimicrobial Agents and Chemotherapy in Washington, doctors who reviewed the therapy given to 11,426 children showed that even a short course of the newer drugs is more effective than the traditional 10-day dose of the older antibiotics.
Pediatricians at the University of Rochester Medical Center found that 25 percent of children treated for strep throat with penicillin ended up back in the doctor's office within three weeks of therapy. Children treated with amoxicillin returned 18 percent of the time. The numbers were 14 percent for older-generation cephalosporins, and just 7 percent for newer ones like cefpodoxime and cefdinir, which are given for just four or five days.
The new results buttress prior work by physicians Michael Pichichero, M.D., and Janet Casey, M.D., showing that more children who receive the older drugs relapse, prolonging their illness and forcing doctors to turn to even stronger drugs. Yet, said Pichichero, doctors across the land continue to prescribe ineffective medications. Studies have shown that approximately 60 to 80 percent of children treated for strep are prescribed amoxicillin; 10 to 20 percent are prescribed penicillin; and just 10 to 20 percent receive a cephalosporin.
"Most doctors are shocked to learn of the high failure rates of the older medications," said Pichichero, a professor of Microbiology and Immunology.........
December 19, 2005
Stress impairs Human Body's Ability To Heal
Moreover, if the couple's relationship is routinely hostile toward each other, the delay in that healing process can be even doubled. The results of this study have major financial implications for medical centers and health care insurers.
The new study, reported in the current issue of the Archives of General Psychiatry, is the latest discovery in a three-decade-long series of experiments underway at the Ohio State University 's Institute for Behavioral Medicine Research. The work is aimed at identifying and then explaining the ways psychological stress can affect human immunity.
Jan Kiecolt-Glaser, a professor of psychiatry and psychology, and partner Ronald Glaser, a professor of molecular virology, immunology and medical genetics, both at Ohio State, say the findings provide important recommendations for patients facing surgery.
"This shows specifically why it is so important that people be psychologically prepared for their surgeries," Kiecolt-Glaser explained.
Colleague Glaser added, "We have enough data now from all of our past studies to basically suggest that hospitals need to modify existing practices in ways that will reduce stress previous to surgery." Both scientists said such stress reduction could lead to shorter hospital stays -- with corresponding lower medical bills -- and a reduced risk of infections among patients.
The scientists focused on a group of 42 married couples who had been together an average of at least 12 years. Each couple was admitted into the university's General Clinical Research Center for two, 24-hour-long visits. The visits were separated by a two-month interval.........
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