Health Meaning

ORLANDO, Florida- - A vaccine against pertussis has lost its edge because new slightly different strains of the bacteria have emerged, say researchers. . The conclusion emphasizes the need to keep the date vaccinations

Pertussis or whooping cough is usually caused by Bordetella pertussis mainly strikes children, causing frightening episodes of cough, shortness of breath and sometimes brain damage or even death. Although it still kills 0,000 to 300,000 children worldwide each year, the disease has largely disappeared from developed countries through immunization of children. In the Netherlands, however, a country with a 96% vaccine coverage, hospitalizations for whooping cough exploded from several dozen in the late 1970s to over 500 in 1999. Other countries, including the United States, have also seen a rebound. So far, it is unclear why this happened.

Five years, a research team led by Frits Mooi at the National Institute of Public Health and the Environment in Bilthoven, the Netherlands, discovered a possible cause. Like many other countries, Holland uses a vaccine developed decades ago, which is killing Bordetella cells. But most recent patients were infected Bordetella strains that have mutations in the genes encoding the two key proteins thought to trigger the production of immunizing antibodies. Perhaps, the researchers hypothesized, changes in minutes make it less effective vaccine, which could explain the reappearance of the disease.

Now there is evidence to support the claim. When the researchers vaccinated mice with the Dutch vaccine, the animals are more susceptible to strains that had mutations that those who do not. Humans probably react the same way, says molecular biologist Audrey King, who presented the findings here on May 22 at a meeting of the American Society for Microbiology. The study shows that a new vaccine is needed that takes into account the changes, said the king.

Changes in Bordetella are a likely factor in the rebound of pertussis, accepts Henry Shinefield, co-director of the Kaiser Permanente Vaccine Study Center in Oakland, California. But there may be other, he said: For example, researchers recently realized that the immunity of a person decreases over the decades. Many seniors are now getting the disease, said Shinefield.

Related Sites

Learn more about the adjustments as a possible cause for Bordetella s' reemergence
information on Pertussis Centers for
pertussis information from the World health Organization Disease Control and Prevention

National Academy of Sciences (NAS) panel found that the risk of cancer arsenic in drinking water are even greater that we thought. The panel report, published on 11 September, just six months after the Bush administration shelved the proposal (EPA) Environmental Protection Agency to suppress arsenic, sparking an outcry from environmentalists and some members of Congress ( Science NOW, March 21). EPA Administrator Christie Whitman, who requested the NAS review, now seems to have no choice but to adopt a standard at least as difficult as it was delayed.

People of studies exposed to high levels of arsenic in water linked the metal at high rates of internal cancers. After a review NAS 1999 revealed that the current standard of 50 parts per billion (ppb) was not protective enough, the outgoing Clinton administration proposed tighten to 10 ppb, based on a study of the arsenic and cancer in Taiwan. But the leaders of Western states with naturally high levels of arsenic have protested that the cost of clean water would be overwhelming. In April, the EPA asked the Academy to examine the latest scientific support levels between 3 ppb and 20 ppb.

This new panel concluded that the analysis on which EPA based the proposed 10 ppb had actually underestimated the risks. "Four new epidemiological studies have been key," says the president of the Robert Goyer committee, a retired pathologist from the University of Western Ontario. New studies of Chile and Taiwan counter the suggestion that the previous results had been distorted by the malnutrition. When panel members recalculated the risk of a slightly different way of analyzing the EPA used, they concluded that the risks of lung cancer and bladder cancer were higher. for example, 10 ppb, the study that EPA based on estimates up to 0.8 additional cases per 1,000 people, while the Panel found a risk of about 1.3 to 3.7 additional cases, depending on the background rate of cancer.

An EPA spokesman declined to speculate whether the new standard is 10 ppb or less, but said Whitman is now "more concerned, not less" risk arsenic. Its decision is due by February.

Related Sites

The NAS report is available online
search site Arsenic

Everyone loves Cipro. Following the deadly bioterrorist attacks on the floor of the United States, many people are suspected of hoarding or even sinking, and supplies in pharmacies are short. As NBC news anchor Tom Brokaw - himself the target of one of the mail attacks - said: "In Cipro we trust" But some scientists warn that obsession is unjustified and can turn

the Cipro popularity began just before the Gulf war, said CJ Peters, former deputy commander of the Institute of the US Army Medical Research of infectious diseases (USAMRIID) in Fort Detrick, Maryland. the US fears Iraq could free coal, and vaccines were in short supply Peters. - now at the University of Texas Medical Branch in Galveston. - and other experts feared that Iraq had developed strains resistant to existing antibiotics So the group focused on a relatively new drug, ciprofloxacin, Bayer, reasoning that Iraq would not understand how to evade. a quick experiment to USAMRIID has shown that the drug worked well in monkeys.

During the war, Bayer provided the government of the United States with 30 million Cipro tablets. In 1998, it appeared that the drug of choice in Management of Biological Casualties Handbook Medical Army, and a year later, a group of experts, writing in The Journal of the American Medical Association , concluded that Cyprus was the drug of choice to treat the unknown strains of coal, because there have been no published reports of resistance. In August 00, the FDA added to the list Cipro antibiotic approved for use in victims of inhalation anthrax.

But Cipro is not better than other antibiotics, such as penicillin and a class of antibiotics called tetracyclines, Peters said; the board he was 10 - its novelty - is gone. Worse, a dependence Cipro bioterrorist could try to produce Cipro-resistant strains of Bacillus anthracis .

In fact, microbiologist Paul Keim of Northern Arizona University in Flagstaff and his colleagues have done just that. Their goal was to find the key mutations that could help scientists quickly detect other Cipro-resistant strains in the future. To minimize the risk, the team used a weakened anthrax strain, but Keim said that the production of a fully virulent strain seems feasible for microbiologists who know the literature. Keim's team will not add to the literature, at least for now. "We have a ready to go paper," said Keim, "but I think I'll sit on it."

Related Sites

FDA on Cipro
Bayer press release about the information Cipro
CDC about anthrax and current bioterrorist attacks

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ATLANTA -. Insecticide-treated nets can save the lives of many children, even in areas where there is intense transmission of malaria this year, according to a new study. The researchers say that the results presented here last month at the annual meeting of the American Society of Tropical Medicine and Hygiene, should give new impetus to a global campaign to bring malaria under control.

The 2-year study, conducted by the Kenya Medical Research Institute in Nairobi and the US Centers for Disease Control and Prevention (CDC) in Atlanta, provides the missing piece in a series of tests . Previous studies - held in Ghana, Gambia, Burkina Faso and coastal Kenya - have shown that nets could save the lives of children, the main victims of malaria. But none of them took place in areas where a person receives hundreds of mosquito bites infected each year. "We were quite skeptical us" that bed nets would it help, said Bernard Nahlen CDC, one of the investigators.

In the trial, researchers randomly assigned each of the 221 villages in western Kenya and their combined 125,000 people into two groups. One group received enough nets to cover all sleeping areas, and the nets were treated with the insecticide permethrin over the next two years. the second group did not receive nets, although they were the data at the end of the trial

the use of nets reduced deaths among children under 1 year. - When most rate of malaria deaths occur --By about 22%. the nets also reduced cases of placental malaria in pregnant women 23%, and 28% less had babies of low birth weight. bed nets even protected those who do not use them, as they were in the vicinity of people who did. Researchers believe that it stems from a reduction in the number of infected mosquitoes

. "We can now make a general recommendation: Everywhere there is malaria, you should use treated nets," says Christian Lengeler the Swiss Tropical Institute in Basel bed nets are already a pillar of Roll Back Malaria, a designed program. to halve the number of malaria deaths by 2010, conducted by the World health Organisation. the study shows that a remarkable low-tech and relatively cheap intervention can help bring this goal closer, said Lengeler.

Related Sites

malaria and mosquito sheet
roll Back malaria
malaria information from the Centers for Disease Control and Prevention

Researchers studying a popular supplement that lines the shelves of health food stores have determined that, in mice at least, it lives up to its claim to lower cholesterol. In addition, the supplement - known guggulsterone - seems to control cholesterol in a different way than existing drugs, lending hope for a potential new class of cholesterol-lowering drugs

For over 00 years, people. gugglesterone are extracted from the resin of the guggul tree in India. Locals eat to treat a wide variety of ailments, from arthritis to obesity; in recent years, it was sold to the West as a natural cholesterol-lowering agent. David Moore, a molecular biologist at the Baylor College of Medicine in Houston, who is a fan of guggulsterone and growth of small trees guggul in his backyard, wanted to determine accurately extract lowers cholesterol.

Moore and his colleagues suspected that the mechanism could be dependent on a receptor called FXR, found in the nucleus of cells. When active, FXR limit the amount of cholesterol the body converts to bile acid, which is then excreted by the body. Indeed, Moore's team found that cells treated with guggulsterone inhibited FXR, which implies that the compound helps turn cholesterol into bile acids. The researchers then focused on two groups of mice: one that is normal and that lacked a functional receptor FXR. After being fed a high cholesterol diet for a week, some animals received guggulsterone. In normal mice, cholesterol levels in the liver declined nearly normal; the guggulsterone has no impact on animals without FXR.

Unlike current cholesterol medications, which block cholesterol production in the liver, Guggulsterone acts through a different mechanism, perhaps accelerate the production of bile acids from cholesterol, or make entirely something else. Other researchers are cautiously optimistic, but say much more work needs to be done. "You are very lucky if it is simple," said Ronald Evans, a molecular biologist at the Salk Institute in La Jolla, California.

Related Sites
page Home of David Moore

A massive trial to test the effects of hormones in postmenopausal women was abruptly halted today after an interim analysis showed that hormones increased the risk breast cancer, coronary heart disease, and stroke. Experts say the findings mean that millions of women currently in drugs should stop doing it. "This is probably the most important medical event in my career," says Wulf Utian, executive director of the North American Menopause Society.

Some 6 million American women currently take a combination of estrogen and progestin, which previous studies had suggested could not only prevent the symptoms of the menopause such as hot flushes, but also to prevent osteoporosis and possibly heart disease when administered over longer periods of time. the researchers suspected that they increased the risk of breast cancer, but it was unclear whether this shift benefits of drugs. much of the evidence has been gleaned from observational studies, in which researchers followed a group of women who decided to take the drugs and a comparable control group, however, the 16,608 women enrolled in the new study. - a part of the women's health Initiative (WHI), a large program set up by the National Heart, Lung, and Blood Institute - were assigned to receive drug or placebo by chance. a much more powerful method

researchers found that hormone therapy reduces the risk of hip fractures - one of the most serious consequences of osteoporosis - 34% and reduced total fracture bone 25%. In addition, the risk of colorectal cancer decreased by 37%. But these benefits were offset by the increase in breast cancer risk, strokes and heart attacks, 26%, 41% and 29%, respectively. Given these results, an independent security group decided that the trial should be stopped after an average period of 5.2 years instead of the planned 8 years of follow up. A paper describing the results should be published on July 17 Journal of the American Medical Association ( JAMA ), was published on the website of the magazine today.

study clearly shows that women should not take hormones for long periods of time, said epidemiologist Deborah Grady of the University of California, San Francisco, who led an earlier study showed the combination did not help women already diagnosed with heart disease. But it can be hard to stop doctors from prescribing pills and women asking for them, she said. "There is an almost mystical belief that it has to work," said Grady.

Related Sites
Document JAMA
An editorial on the study, also in JAMA
Initiative women's health
learn more about why the trial was stopped
the North American Menopause Society

despite concerns about the risks of hormone replacement therapy for menopausal women, a benefit is clear: It makes bones stronger. Now a study suggests that it might be possible to maintain the benefits of estrogen while minimizing its risks. A synthetic hormone has been shown to stimulate bone strength in mice without affecting the reproductive organs.

estrogen makes women less likely to develop osteoporosis and suffer debilitating fractures. But this deal comes with an increased risk of breast cancer, pulmonary embolism, myocardial infarction and stroke ( Science , 19 July, p. 325). Rationale The effects of this estrogen on various tissues can count on various cell signaling cascades, a team led by Stavros Manolagas the University of Arkansas for Medical Sciences in Little Rock identified a synthetic hormone called estren that activates a sub all these pathways.

Estren Tinkers with cell building teams that continuously reshape the bone. At one point, Manolagas said, there are 5 million to 10 million sites on a human skeleton which cells called osteoclasts dig trenches in the tiny bones that are filled by bone forming osteoblasts. After menopause, osteoclasts ahead osteoblasts, which makes them more porous and brittle bone.

Manolagas team found that in the test tube, both estrogen and estren encouraged osteoclasts to self-destruction while extending the lifespan of osteoblasts. And in mice whose ovaries were removed, both compounds increased bone density and strength. But they had markedly different effects on the reproductive organs, the team reports in the October issue 25 Science . In mice ovariectomized, uterus loses almost two-thirds of its weight. Estrogen, but not estren, prevents this loss. And while estrogen stimulates the growth of breast cancer cells in culture, estrene not. The reason Manolagas said, is that estren an active way "nongenotropic" signaling that affects the bones but not the reproductive organs.

What compounds such as estren will be useful in humans remains to be seen. "If compounds such as estrogen could be used to maintain bone density with little or no side effects in older women, it would be huge," says molecular endocrinologist Geoffrey Greene of the University of Chicago.

Related Sites
Manolagas the site of
Greene site
basic information about osteoporosis of the National Institute on aging
information and resources on HRT NIH

A perennial puzzle to cancer researchers is why some tumors spread to other parts of the body, or metastasize, while others do not. Because most cancer deaths result from metastasis, the answer to this question could help doctors predict metastatic disease and help choose the optimal treatment. Now researchers have taken a small step in this direction: they have deciphered a "signature" gene, which in many tumor samples, seems to predict whether a cancer spreads

The tumor cells metastasize once that they acquire certain genetic. mutations. These could make a more robust cell in a foreign environment - say, when a cell moves within the bone - or more able to escape the primary tumor survive and all rushed into the bloodstream. But the distinction between cancer cells and the garden-variety smarter metastatic type has been difficult.

gene expression In a recent attempt, oncologist Todd Golub of Dana-Farber Cancer Institute in Boston, Massachusetts, and colleagues collected profiles taken from public databases, from 76 tumors. Sixty-four were of a primary site (though the team members did not know if these cancers had later metastasized), and 12 were metastases. Because the primary and metastatic samples are not the same people, and because the samples were taken from a mishmash of cancer (lung, breast, prostate, colorectal, uterus and the ovary), Golub did not really expect to see something interesting.

to the researchers' surprise, they found distinct patterns of expression of the 17 genes. They were particularly intrigued to see that some primary tumors shared a pattern of expression with metastatic ones. These tumors might be those who would spread? The group turned to several profiles: 78 breast cancer, 62 lung cancer, and 21 samples of prostate cancer, all primary tumors and tracking information to whether they had metastasized. Although a poor result was possible without the gene expression profile, patients with the genetic signature have been found to survive for less time than those who do not have it, they wrote in the online edition of the December 9 of Nature Genetics .

"This study has provided solid evidence that the molecular signature of metastasis is high on the primary tumor," said Mary Hendrix, a cancer researcher at the University of Iowa in Iowa .. But City Hendrix points out that the study should be repeated with a larger sample also, she said, it would be nice to know the function of 17 genes - some of which had been previously linked to cancer. - Because this could help refine tumor treatments

Related Sites
the homepage Metastasis research Society
the homepage of Todd Golub

As many people age, their sugar levels in the blood crawl. In extreme cases, this can lead to diabetes. But a new study suggests that sugar levels in the blood, even moderately high can cause memory impairment and reduce the hippocampus -. Part of the brain critical to store new information

Many elderly people develop a condition called impaired glucose reduced Tolerance- -an of the body's ability to move glucose from the blood into the cells using as energy source. This increases the level of sugar in the blood, which can impair memory. Diabetics tend to score poorly on tests of memory, for example, as individuals with glucose levels in the blood that are not yet diabetic. However, it is unclear whether this loss of memory resulted in brain damage.

Antonio Convit, a psychiatrist at New York University, and colleagues examined 30 healthy older subjects between 53 and 86 years. The team took images of magnetic resonance brain subjects, gave them a battery of cognitive tests, and performed a standard test that measures their ability to remove glucose from the blood. As expected, subjects with sugar levels in the blood less well in memory tests. In addition, the hippocampus was smaller. No other brain structures differ between groups, Convit and colleagues report online this week in the Proceedings of the National Academy of Sciences .

Although the cause of withdrawal does not know, Convit emphasizes that the hippocampus has long been known to be particularly vulnerable to physiological stress. reduced glucose tolerance could provide such stress by starving the hippocampus when it is most needed fuel. "In the long term, that may be causing the damage," says Convit.

This scenario makes sense for Carol Greenwood, a nutritionist at the University of Toronto, who thinks that the hippocampus may be in trouble even before diabetes sets in. It is a "slippery slide down the slope," she said. Neuroendocrinologist Bruce McEwen of Rockefeller University in New York agrees, but expects more evidence to nail him. "At this stage we do not know yet what are the causal factors. "

Related Sites
Department of psychiatry University of New York
laboratory Bruce McEwens at the Rockefeller University
laboratory Carol Greenwood, University of Toronto

New evidence shows that hormone replacement therapy (HRT) does not improve the quality of life for postmenopausal women. According to Deborah Grady, an epidemiologist at the University of California, San Francisco, the message is clear for women without menopausal symptoms:

The "There is no role for hormone therapy." first bad news for HRT came in July 02 when the Initiative on women's health (WHI) 16,608 patients showed that HRT - Wyeth Prempro, in particular - increased the risk of breast cancer, heart attack and stroke ( science NOW, July 9, 02). The new analysis of WHI, published online March 17 by the New England Journal of Medicine (NEJM) , shows that women taking Prempro had little to no benefit compared to placebo in the fight against symptoms such as hot flashes, vaginal dryness, and forgetfulness. The finding is surprising and ironic, given that many women continued HRT specifically to improve the quality of life in the months since the first WHI results were announced.

The new study, led by Jennifer Hays of Baylor College of Medicine in Houston, found no significant improvement in vitality, mental health, depression or sexual satisfaction. However, a subgroup of moderate to severe reporting hot flashes, night sweats and sleep disorders had a "small advantage" to relieve sleep disorders. The study has its limitations. Most women were asymptomatic when they entered the office, and some women with severe symptoms probably did not sign for fear of being given a placebo. Consequently, the study may have little benefit for women with symptoms underestimated.

The risks of HRT However, since even women with severe symptoms should consider alternatives, Grady wrote in an editorial that will be published with the report in the May 8 issue of NEJM . For those who must take hormones, clinicians should try at least once every six months to reduce the dose, and then stop.

Some questions remain.

Sites Some researchers have questioned whether the results of the WHI apply to all HRT combinations, or lower doses, or short-term or intermittent use, could limit or eliminate the disadvantages. on
Hays website
Initiative for Women's Health