December 13, 2007, 9:53 PM CT

Why vaccines directed against cancer don't work

Scientists from the University of Missouri and Imperial College London have found evidence suggesting why vaccines directed against the virus that causes AIDS and a number of cancers do not work. This research is being reported in the Dec. 14 edition of The Journal of Biological Chemistry.

In research spanning more than a decade, Gary Clark, associate professor of Obstetrics, Gynecology and Womens Health in the MU School of Medicine, and Anne Dell, an investigator at Imperial College London, observed that HIV, aggressive cancer cells, H. pylori, and parasitic worms known as schistosomes carry the same carbohydrate sequences as a number of proteins produced in human sperm.

Its our major Achilles heel, Clark said. Reproduction is mandatory for the survival of our species. Therefore we are hard-wired to protect our sperm and eggs as well as our unborn babies from any type of immune response. Unfortunately, our results suggest that a number of pathogens and tumor cells also have integrated themselves into this protective system, thus enabling them to resist the human immune response.

During the initial stages of life, the body goes through a process where it self-identifies, determining which cells and proteins belong in the body, so it can detect those that do not. After this time, anything foreign is deemed as dangerous, unless the immune system is specifically told to ignore those cells and proteins. This situation arises primarily during reproduction......... Posted by: Janet      Read more         Source

December 13, 2007, 9:46 PM CT

Early treatment stops epilepsy

Yale School of Medicine researchers have shown for the first time that it is possible to suppress the development of epilepsy in genetically predisposed animalswhich could open the door to treating epilepsy as a preventable disease.

According to the study published this month in Epilepsia, early treatment of epilepsy-prone rats with the anti-convulsant medicine ethosuximide before the onset of seizures led to a marked suppression of seizures both later in life and months after treatment stopped.

Current treatments for epilepsy may control seizures, but they do nothing to alter the underlying disease, said Hal Blumenfeld, M.D., associate professor of neurology and lead author of the study. These findings are important because they set the stage for prevention of epilepsy in genetically susceptible people.

Epilepsy is a common neurological disorder that affects about 50 million people worldwide. Typically typically it is characterized by seizurestemporary loss of consciousness or muscular controlthat are precipitated by abnormal electrical overload on neurons within the brain.

Using a combination of molecular profiling, electroencephalogram (EEG) recordings, and power spectral analysis, Blumenfeld and his colleagues demonstrated that ethosuximide effectively blocked the expression of an epilepsy-associated maladaptive protein within neurons of the brain and reduced the number of seizures in treated animals......... Posted by: Daniel      Read more         Source

December 13, 2007, 9:08 PM CT

Overweight People Are More Likely to Have Bad Breath

Now there's another good reason to go on that diet after the holidays. Tel Aviv University scientists have published a study that finds a direct link between obesity and bad breath: the more overweight you are, the more likely your breath will smell unpleasant to those around you.

The research, led by breath expert Prof. Mel Rosenberg from the Department of Human Microbiology and The Maurice and Gabriela Goldschleger School of Dental Medicine, Sackler Faculty of Medicine at Tel Aviv University, was published in the Journal of Dental Research in October. The study also reported, for the first time, scientific evidence that links bad breath to alcohol consumption.

"The finding on alcohol and bad breath was not surprising because the anecdotal evidence was already there," says Prof. Rosenberg. "However, the finding that correlated obesity to bad breath was unanticipated".

A Weighty Sample

The study was done in Israel and included a sample of 88 adults of varying weights and heights. While at a clinic for a regular check-up, they were asked by graduate student Tsachi Knaan, a co-author in the study, whether he could test the odor of their breath and ask questions about their daily habits.

Prof. Rosenberg, Knaan and Prof. Danny Cohen concluded from the data that overweight patients were more likely to have foul-smelling breath. "This finding should hold for the general public," says Prof. Rosenberg. "But we don't have any scientific evidence as to why this is the case. That will be the next step"......... Posted by: JoAnn      Read more         Source

December 13, 2007, 8:59 PM CT

Adapting to pregnancy in human evolution

The human spine evolved differently in males and females in order to alleviate back pressure from the weight of carrying a baby, as per research spearheaded at The University of Texas at Austin.

The lumbar differences are documented for the first time in the Dec. 13 issue of Nature.

The scientists believe the adaptation first appeared at least two million years ago, in the early human ancestor Australopithecus. The male-female difference does not appear in chimpanzees, meaning the evolution to walking upright led to the adaptation.

"Natural selection favored this adaptation because it reduces extra stress on a pregnant female's spine," said University of Texas at Austin anthropologist Liza Shapiro, who conducted the research with graduate student Katherine K. Whitcome, now a post-doctoral fellow at Harvard University. "Without the adaptation, pregnancy would have placed a heavier burden on back muscles, causing considerable pain and fatigue and possibly limiting foraging capacity and the ability to escape from predators."

Harvard anthropologist Daniel Lieberman also contributed to the study, which shows the key differences between males and females appear in the lower back, or lumbar portion of the spine.

Human spines have a unique forward curve in the lumbar region, but the curve extends across more vertebrae in females. That helps offset harmful forces that might occur on the spine when pregnant women lean back or hyperextend their spines to balance the weight of the fetus, Shapiro said. The joints between the vertebrae also are larger in females and angled differently than in males to better support the extra weight......... Posted by: Emily      Read more         Source

December 12, 2007, 10:14 PM CT

Too much fructose could leave dieters sugar shocked

Heres one tip for how to eat at the holidays: Dont take your cues from Santa. The sugary cookies and fat-laden fruitcakes the mythical North Pole resident eats are a no-no. But you dont have to go no-carb to stay fit at the holidays, either, University of Florida scientists say.

In fact, a number of dieters may actually be cutting out the wrong foods altogether, as per findings from a UF paper published recently in the European Journal of Nutrition. Dieters should focus on limiting the amount of fructose they eat instead of cutting out starchy foods such as bread, rice and potatoes, report the researchers, who propose using new dietary guidelines based on fructose to gauge how healthy foods are.

Theres a fair amount of evidence that starch-based foods dont cause weight gain like sugar-based foods and dont cause the metabolic syndrome like sugar-based foods, said Dr. Richard Johnson, the senior author of the report, which evaluated several recent studies on fructose and obesity. Potatoes, pasta, rice may be relatively safe in comparison to table sugar. A fructose index may be a better way to assess the risk of carbohydrates correlation to obesity.

A number of diets -- including the low-carb variety -- are based on the glycemic index, which measures how foods affect blood glucose levels. Because starches convert to glucose in the body, these diets tend to limit foods such as rice and potatoes......... Posted by: JoAnn      Read more         Source

December 12, 2007, 10:09 PM CT

Greater agreement on the attractiveness of faces

A new study from scientists at Harvard University shows that friends, siblings and spouses are more likely than strangers to agree on the attractiveness of faces. Recent research regarding facial attractiveness has emphasized the universality of attractiveness preferences, and in this study there was some agreement among the strangers - but the close relations were in even greater agreement regarding facial attractiveness.

The study appears in the current issue of the journal Perception, and was led by Richard Russell, a postdoctoral researcher in the Department of Psychology in the Faculty of Arts and Sciences at Harvard University, and Matthew Bronstad a postdoctoral researcher at the Schepens Eye Research Institute, an affiliate of Harvard Medical School. The work was done while Bronstad was with Brandeis University.

While there are some universal standards of beauty, this study shows that perception and standards of attractiveness are more likely to be shared among individuals who know each other well, says Russell.

In the study, 113 participants were asked to rate 74 faces on a scale from one to seven, from very attractive to very unattractive. Among the participants were 20 pairs of spouses, 20 pairs of siblings and 41 pairs of close friends. Each of the pairs completed the test separately, so that they could not influence each others ratings. The participants ranged widely in age, but were of a similar background, and were all North American and caucasian. The faces rated were all young and caucasian......... Posted by: Janet      Read more         Source

December 12, 2007, 9:52 PM CT

Link between women's hormones and mood disorders

Countless movies and TV shows make light of womens so-called moodiness, often jokingly attributing it to their menstrual cycle or, on the other hand, to menopause. In fact, mood disorders are a serious and pervasive health problem, and large-scale population studies have observed women are 1.5 to 3 times more likely to suffer from major depressive disorder than are men.

In a newly published study, womens health experts from the University of Alberta argue there is an urgent need for carefully designed, gender-specific research to better understand the relationship of female sex hormones to mood states and disorders.

The reasons for the gender disparity in rates of depression are not completely understood, says Kathy Hegadoren, the Canada Research Chair in Stress Disorders in Women at the University of Alberta.

But there is growing evidence that estrogens have powerful effects beyond their role in reproductionthat they play a critical role in mood disorders in womenand this opens new avenues for research into the underlying biological mechanisms and therapy of depression.

Estrogen can be used to treat various mood disturbances in womensuch according toimenopausal, postmenopausal and postpartum depressionbut the results of these therapys can be difficult to interpret because scientists are only beginning to recognize the complex interactions among estrogens, serotonin and mood......... Posted by: Emily      Read more         Source

December 12, 2007, 9:48 PM CT

'Retrospective Rubber' Remembers Its Old Identities

Scientists at the University of Rochester have developed a shape-memory rubber that may enable applications as diverse as biomedical implants, conformal face-masks, self-sealing sutures, and "smart" labels.

The material, described in the journal Advanced Materials, forms a new class of shape-memory polymers, which are materials that can be stretched to a new shape and will stay in that form until heated, at which time they revert to their initial shape.

Unlike conventional shape-memory polymers, however, the new material is transparent, rubbery, and most importantly, engineers will be able to control the speed at which it returns to its original shape. Other shape memory polymers use crystallization to hold a temporary shape, which often makes them opaque, hard, and brittle in their frozen states, and this can limit their use.

"At higher temperatures the material stretches like a rubber band, but, at lower temperatures, it stiffens up," says Mitchell Anthamatten, assistant professor of chemical engineering and inventor of the material. "This property can be used to temporarily hold the material in a deformed shape; and its original shape can be recalled by heating. Imagine an optical lens that can be triggered to change shape, a face-mask that can fit any user, or a biomedical implant that changes shape slow enough for a surgical procedure"......... Posted by: Daniel      Read more         Source

December 11, 2007, 10:39 PM CT

The bear necessities of aging

As per George Bernard Shaw: We dont stop playing because we grow old; we grow old because we stop playing, but how fast does that aging occur once started" In the case of populations of salmon in Alaska studied by Stephanie Carlson and his colleagues at the University of Washington and McGill University and reported on in this weeks PLoS ONE, it all depends on how choosy are the bears which feed on them.

Pacific salmon are noted for not feeding during their breeding period, relying instead on stored energy reserves and for their rapid senescence the physiological deterioration linked to aging once breeding is over. It is, thus, more beneficial for bears to consume fish with fewer signs of senescence because these fish have more energy reserves. However, these fresh fish are also more vigorous and harder to catch and so are more effectively caught in smaller, shallower streams.

Carlson and his colleagues studied populations of salmon and brown bears in six creeks in southwest Alaska to determine whether the rate of senescence in salmon was driven primarily by the rate of predation by bears or by the tendency of the bears to prey on salmon with less evidence of senescence. They measured the reproductive lifespan of each fish as the number of days between stream entry and death and recorded the mode of death for each fish. They observed that the selectivity of the bears for salmon of various senescent conditions was the prime factor determining the rate of senescence in the salmon......... Posted by: Janet      Read more         Source

December 11, 2007, 10:38 PM CT

Obesity reduces chances of spontaneous pregnancy

A new study of obesity and the probability of pregnancy has shown that a womans chances of a spontaneous pregnancy steadily decrease the fatter she is.

In the first prospective cohort study to examine the relationship between body mass index (BMI) and pregnancy chances in women who have no obvious reasons for infertility but who have spent a year or more trying unsuccessfully to conceive, the study observed that for every BMI unit above 29 kg/m2, the probability of pregnancy was reduced by four per cent in comparison to women with a BMI between 21-29 kg/m2. Very obese women (BMI 35-40) had a probability of pregnancy that was between 26 and 43 per cent lower than women with a BMI between 21-29.

Dr Jan Willem van der Steeg, the lead author of the study [1], which is published in Europes leading reproductive medicine journal, Human Reproduction, today (Wednesday 12 December) said: This reduction in fertility is comparable to the increment of one year in female age. This study tells us that not only obese women with anovulation have lower chances of conception, but also obese women with a regular cycle. Given the increased prevalence of obesity, this is a worrying finding. The occurence rate of obesity is reckoned to be 12 per cent in women of child-bearing age in Western Europe and 25 per cent in North America......... Posted by: JoAnn      Read more         Source