April 7, 2008, 10:35 PM CT
Your baby's brain on drugs
Eventhough behavioral studies clearly indicate that exposure to drugs, alcohol and tobacco in utero is bad for a baby's developing brain, specific anatomic brain effects have been hard to tease out in humans. Often users don't limit themselves to one substance, and demographic factors like poverty can also influence brain development.
Now, an NIH-funded study using magnetic resonance imaging (MRI) brain scans, led by Children's Hospital Boston neurologist Michael Rivkin, MD, suggests that prenatal exposure to cocaine, alcohol, marijuana or tobacco (alone or in combination) may have effects on brain structure that persist into early adolescence. The findings, reported in the recent issue of Pediatrics, are of public health significance, the scientists say, since it's estimated that more than 1 million babies born annually in the United States have been exposed to at least one of these agents in utero.
Scientists at Children's and Boston Medical Center employed volumetric MRI imaging to study the brain structure of 35 young adolescents prenatally exposed to cocaine, marijuana, alcohol or tobacco. The children, who averaged 12 years old at the time of imaging, were part of part of an historic cohort of children assembled by Deborah Frank, MD at Boston Medical Center and followed there since birth. Prenatal exposures were confirmed by a combination of maternal history, urine testing of the mother or urine or meconium (stool) testing of the infants at birth.........
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April 6, 2008, 8:26 PM CT
Alligator blood for antibiotic-resistant infections
Alligator blood could provide a powerful new source of antibiotics for fighting deadly "superbugs" and other infections, researchers say.
Credit: Photo credit: Courtesy of U.S. Fish & Wildlife Service.
Despite their reputation for deadly attacks on humans and pets, alligators are wiggling their way toward a new role as potential lifesavers in medicine, biochemists in Louisiana reported today at the 235th national meeting of the American Chemical Society. They described how proteins in gator blood may provide a source of powerful new antibiotics to help fight infections linked to diabetic ulcers, severe burns, and superbugs that are resistant to conventional medication.
Their study, described as the first to explore the antimicrobial activity of alligator blood in detail, found a range of other promising uses for the gators antibiotic proteins. Among them: combating Candida albicans yeast infections, which are a serious problem in AIDS patients and transplant recipients, who have weakened immune systems, the researchers say.
Were very excited about the potential of these alligator blood proteins as both antibacterial and antifungal agents, says co-author of study Mark Merchant, Ph.D., a biochemist at McNeese State University in Lake Charles, La. Theres a real possibility that you could be treated with an alligator blood product one day.
Prior studies by Merchant showed that alligators have an uncommonly strong immune system that is very different from that of humans. Unlike people, alligators can fight microorganisms such as fungi, viruses, and bacteria without having previous exposure to them. Researchers think that this is an evolutionary adaptation to promote quick wound healing, as alligators are often injured during fierce territorial battles.........
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April 6, 2008, 8:21 PM CT
Acetaminophen increases muscle mass
Taking daily recommended dosages of ibuprofen and acetaminophen caused a substantially greater increase over placebo in the amount of quadriceps muscle mass and muscle strength gained during three months of regular weight lifting, in a study by physiologists at the Human Performance Laboratory, Ball State University.
Dr. Chad Carroll, a postdoctoral fellow working with Dr. Todd Trappe, reported study results at Experimental Biology 2008 in San Diego on April 6. His presentation was part of the scientific program of the American Physiological Society (APS).
Thirty-six men and women, between 60 and 78 years of age (average age 65), were randomly assigned to daily dosages of either ibuprofen (such as that in Advil), acetaminophen (such as that in Tylenol), or a placebo. The dosages were identical to those recommended by the manufacturers and were selected to most closely mimic what chronic users of these medicines were likely to be taking. Neither the volunteers nor the researchers knew who was receiving which therapy until the end of the study.
All subjects participated in three months of weight training, 15-20 minute sessions conducted in the Human Performance Laboratory three times per week. The scientists knew from their own and other studies that training at this intensity and for this time period would significantly increase muscle mass and strength. They expected the placebo group to show such increases, as its members did, but they were surprised to find that the groups using either ibuprofen or acetaminophen did even better. An earlier study from the laboratory, measuring muscle metabolism (or more precisely, muscle protein synthesis, the mechanism through which new protein is added to muscle), had looked at changes over a 24 hour period. This acute study observed that both ibuprofen and acetaminophen had a negative impact, by blocking a specific enzyme cyclooxygenase, usually referred to as COX.........
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April 6, 2008, 8:13 PM CT
More likely to choose cocaine over food
Having a lower social standing increases the likelihood that a monkey faced with a stressful situation will choose cocaine over food, as per a research studyat Wake Forest University School of Medicine. More dominant monkeys undergoing the same stressful situation had fewer changes in brain activity in areas of the brain involved in stress and anxiety and were less likely to choose cocaine.
Robert Warren Gould, a graduate student in the laboratory of Michael A. Nader, Ph.D., presented the study results Sunday at Experimental Biology 2008 in San Diego. The presentation was part of the scientific program of the American Society for Pharmacology and Experimental Therapeutics (ASPET).
Male cynomolgus monkeys live in a complex social structure in which the social hierarchy is established by physical aggression and maintained by clear signals. A monkey that has established his dominance over another monkey can elicit a subordinate response with no more than a meaningful look.
The scientists exposed four dominant and four subordinate monkeys to a socially stressful situation in which an individual monkey was taken out of his home cage and placed in an unfamiliar cage surrounded by four unfamiliar animals. The monkey was physically safe, but he could see and hear the animals around him engaging in aggressive behavior.........
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April 6, 2008, 8:08 PM CT
Genes have big impact on blood pressure
New Haven, Conn. -Yale University scientists report today in the journal Nature Genetics that they have discovered that rare genetic variants can be linked to a dramatically lower risk of developing hypertension in the general population.
The insight that rare mutations may collectively play a large part in the development of common yet complex diseases such as high blood pressure also has implications for the diagnosis and therapy of diseases such as diabetes and schizophrenia.
The team of scientists was led by Richard Lifton http://www.med.yale.edu/bcmm/RPL/index.html , chair of the Department of Genetics and Sterling Professor of Genetics and Internal Medicine at Yale, and Daniel Levy, director National Heart, Lung and Blood Institute's Framingham Heart Study.
The researchers analyzed DNA samples from 3,125 people who participated in the Framingham Heart Study, a long-running epidemiology survey that has led to a treasure trove of information about the causes of heart disease.
They decided to study the health impact of three genes regulating the processing of salt in the kidney and each known to cause dangerously low blood pressure levels when inherited with two defective copies (one from each parent). The scientists speculated that people who carry only one defective copy might be less prone to hypertension.........
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April 6, 2008, 8:02 PM CT
Growing body of knowledge of genetics of height
Researchers are beginning to develop a clearer picture of what makes some people stand head and shoulders above the rest. A team of scientists who last year identified the first common version of a gene influencing height has now identified a further twenty regions of the genome which together can make a height difference of up to 6cm.
The results, published together with two independent studies online today in the journal Nature Genetics, mean that researchers now know of dozens of genes and genetic regions that influence our height. This provides researchers with a fascinating insight into how the body grows and develops normally and may shed light on diseases such as osteoarthritis and cancer.
Unlike many other body size characteristics such as obesity, which is caused by a mix of genetic and environmental factors (so called "nature and nurture"), 90 per cent of normal variation in human height is due to genetic factors rather than, for example, diet. Last year, a team of scientists including Dr Tim Frayling from the Peninsula Medical School, Exeter, and Professor Mark McCarthy from the University of Oxford identified the first common gene variant to affect height, though it made a difference of only 0.5cm.
Now, using DNA samples from over 30,000 people, a number of taken from the Wellcome Trust Case Control Consortium the largest study ever undertaken into the genetics underlying common diseases and from the Cambridge Genetics of Energy Metabolism (GEM) consortium and the CoLaus Study in Switzerland, the scientists have identified 20 loci (regions of genetic code), common variations of which influence adult height.........
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April 3, 2008, 10:00 PM CT
Breast cancer risk lingered years after HRT
A follow-up study of postmenopausal women who took the combination of estrogen and progestin for more than five years as part of the landmark Women's Health Initiative shows that the women continued to face an increased risk for breast cancer nearly three years after they quit taking the hormones.
The new study also shows that while some of the other health risks and benefits diminished after the women had stopped taking the estrogen-progestin combination, the overall health risk was 12 percent higher at the end of eight years (with women on the pills for an average of 5.6 years and then off for 2.4 years) compared with those who took placebos. This was largely due to the high risks of breast cancer, strokes and serious blood clots during the original trial while the women took the hormones.
The Stanford University School of Medicine researcher who is the senior author of the follow-up study said the results indicate that the potential harms from estrogen-progestin treatment still outweigh the benefits, and that women should continue to be cautious in deciding whether to take the hormones to relieve menopausal symptoms.
"Menopausal women really need to think through whether using estrogen-progestin is the right thing to do, especially if continued for more than a few years," said Marcia Stefanick, PhD, professor of medicine at the Stanford Prevention Research Center, noting that the breast-cancer risks apply only to women who take the combination treatment, and not those who take estrogen alone. A different portion of the WHI study showed that estrogen-only treatment doesn't increase the risk of breast cancer.........
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April 3, 2008, 9:51 PM CT
Colon Cancer's Potential for Metastasis
Some colon cancers are destined to spread to the liver and other parts of the body, whereas others are successfully treated by surgical removal of the tumor. Now, Howard Hughes Medical Institute researchers have observed that the ability of a colon tumor to metastasize arises early in its development.
Those colon cancers that spread carry the ability to metastasize from the time they become malignant, the scientists found. They don't need to acquire any new genetic mutations to become metastatic. The research also suggests that once a colon carcinoma develops, if it is going to spread outside the colon, it will do so in less than two years.
"The ability to metastasize is hard-wired into this group of tumors in the colon," said Sanford Markowitz, a Howard Hughes Medical Institute investigator at Case Western Reserve University. "It isn't something that happens after a cancer cell wanders off and leaves the colon."
Markowitz and colleagues published their findings in the Proceedings of the National Academy of Sciences on March 3, 2008.
Colon cancer is the second leading cause of cancer mortality in the United States, causing about 60,000 deaths annually. But there are a number of more cases of colon cancer that are cured by surgical removal of the tumor. Markowitz and his team wanted to understand the genetic differences between the two types.........
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April 3, 2008, 8:18 PM CT
Continuous oral contraceptives better at easing pain, bleeding
Continuous oral contraceptives may be more effective than the standard 28-day birth control pills in suppressing the ovary, as per researchers. They say that the continuous pill also causes a significant improvement in pain and behavioral changes.
"We have provided a biological proof of concept that both the ovary and the lining of the uterus are suppressed better and quicker with the continuous pill than with the cyclic pill. And there is no harmful effect on the lining of the uterus either," said Richard Legro, M.D., professor of obstetrics and gynecology, Penn State College of Medicine and lead author of the study.
Standard 28-day birth control pills mimic a woman's natural menstrual cycle, while preventing pregnancy. A standard dose includes 21 hormone pills to suppress growth in the endometrium, the lining of the uterus, and seven placeholder placebo pills.
Continuous oral contraceptives may be more effective in treating several medical conditions, where continuous ovarian suppression is desired, such as acne, hirsutism, premenstrual syndrome, endometriosis and polycystic ovary syndrome. But there have been few detailed studies of ovarian function on the pill to demonstrate this effect.
Legro and colleagues compared the effectiveness of continuous oral contraceptives with that of the cyclical pills. The scientists monitored 62 healthy women, randomly assigned to receive either cyclical or continuous birth control pills, for six months with both scientists and participants blinded to the study group.........
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April 2, 2008, 10:16 PM CT
Natural trans fats have health benefits
Contrary to popular opinion, not all trans fats are bad for you.
University of Alberta researcher Flora Wang observed that a diet with enriched levels of trans vaccenic acid (VA) a natural animal fat found in dairy and beef products can reduce risk factors linked to heart disease, diabetes and obesity.
Results indicated this benefit was due in part to the ability of VA to reduce the production of chylomicrons particles of fat and cholesterol that form in the small intestine following a meal and are rapidly processed throughout the body. The role of chylomicrons is increasingly viewed as a critical missing link in the understanding of conditions arising from metabolic disorders.
Our results provide further evidence of the important role of chylomicrons in contributing to risk factors linked to metabolic disorders, said Wang, a PhD candidate in the University of Alberta Faculty of Agricultural, Life and Environmental Sciences. They also indicate a strong opportunity for using diets with enhanced VA to help reduce these risk factors.
The research involved two VA feeding trials one short-term (three weeks) and one long-term (16 weeks) using model rat species for obesity and the metabolic syndrome.
The results, presented recently at the International Symposium on Chylomicrons in Disease, included novel findings that VA may have direct effects on the intestine. In addition, they showed key metabolic risk factors were reduced. For example, in the long-term trial, total cholesterol was lowered by approximately 30 per cent, LDL cholesterol was lowered by 25 per cent and triglyceride levels were lowered by more than 50 per cent.........
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