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August 14, 2006, 11:39 PM CT

West Nile Virus Antibody Binding Site

West Nile Virus Antibody Binding Site
Scientists have learned the precise location where an antibody binds to the West Nile virus, and they have suggested a mechanism for how this antibody neutralizes the virus to prevent infection.

"Science doesn't yet fully understand exactly how neutralizing antibodies work," said Michael Rossmann, the Hanley Distinguished Professor of Biological Sciences in Purdue's College of Science. "This work has shown precisely where the antibody binds to the virus, and we now have a theory for how it interacts with the virus to disarm it. Perhaps we are starting to understand why this particular antibody can inhibit the infectivity of the virus, which is important to understand if a vaccine is going to be developed".

Purdue worked with scientists from the Washington University School of Medicine in St. Louis.

West Nile belongs to a family of viruses known as flaviviruses, which includes many dangerous insect-borne disease-causing viruses. The antibody attaches to a protein called an E protein, for envelope protein, which makes up the virus's outer shell. There are 180 copies of E proteins symmetrically arranged in 60 sets of three, forming a geometric shape called an icosahedron, which is made up of triangular facets.

The researchers, however, were surprised to discover that this antibody recognizes only two of the E proteins in each set of three, said Bärbel Kaufmann, a postdoctoral research associate working in the Rossmann lab.........

Posted by: Mark      Permalink         Source


August 13, 2006, 6:00 PM CT

Simplified Treatment Of HIV Infection

Simplified Treatment Of HIV Infection
A preliminary study indicates that using a single boosted protease inhibitor instead of the standard regimen of 3 drugs for maintenance treatment may be an effective therapy for select patients with HIV infection, as per a research studyin the August 16 issue of JAMA, a theme issue on HIV/AIDS.

Susan Swindells, M.B.B.S., of the University of Nebraska Medical Center, Omaha, presented the findings of the study today at a JAMA media briefing at the International AIDS Conference in Toronto.

The long-term adverse effects, expense, and difficulty of sustained adherence to multidrug antiretroviral regimens have prompted studies of simpler therapies for human immunodeficiency virus type 1 (HIV-1) infection. Treatment cessation, intermittent treatment, and induction-maintenance (a few months of triple treatment followed by simplified treatment) regimens have been reviewed with mostly inferior results, as per background information in the article.

Dr. Swindells and his colleagues conducted a study to determine whether a simplified maintenance treatment with the antiretroviral medicine "boosted" atazanavir alone after virologic suppression (cessation of detectable HIV virus replication) would not markedly increase the risk of virologic failure. Protease inhibitors, such as atazanavir, are often combined with a small dose of ritonavir to increase blood levels a phenomenon known as "boosting." This regimen was selected because of low pill burden, once-daily dosing, safety, and unique resistance profile. The 24-week pilot study, conducted between Sept. 2004 and April 2006, included 36 HIV-infected adults with virologic suppression for 48 weeks or longer receiving their first protease inhibitor (PI)based regimen. Participants switched PIs to atazanavir-ritonavir at entry and discontinued nucleoside analog reverse transcriptase inhibitors (NRTIs) after 6 weeks. Virologic failure was defined as two consecutive HIV-1 RNA measurements of 200 copies/mL or more. The final analysis included 34 patients.........

Posted by: Mark      Permalink         Source


August 13, 2006, 5:58 PM CT

Rapid expansion of HIV treatment

Rapid expansion of HIV treatment
A massive scale-up of HIV/AIDS therapy programs at urban primary care sites in Zambia has produced favorable patient outcomes, demonstrating that expansion of such programs in sub-Saharan Africa is feasible, with good results, as per a research studyin the August 16 issue of JAMA, a theme issue on HIV/AIDS.

Jeffrey S.A. Stringer, M.D., of the Centre for Infectious Disease Research in Zambia, Lusaka, and the University of Alabama at Birmingham, presented the findings of the study today at a JAMA media briefing at the International AIDS Conference in Toronto.

Zambia's 11.5 million residents are among the world's poorest and most severely affected by acquired immunodeficiency syndrome (AIDS), as per background information in the article. About 16 percent of the adult population is infected with human immunodeficiency virus 1 (HIV 1), including 22 percent in the capital city Lusaka. In 2003, more than 90,000 Zambians died of HIV disease. Historically, only the wealthiest citizens have had access to antiretroviral treatment (ART) for HIV through private medical practices.

The Zambian Ministry of Health, aiming to provide public access to therapy, in 2002 started pilot ART distribution programs at two of the country's largest hospitals. The program filled almost immediately and in May 2004 expanded to four clinics in the Lusaka Urban District, which were staffed primarily by clinical officers and nurses. In the following 18 months, all fees for patients seeking care were eliminated, ART and laboratory tests were offered for free and the program expanded to 14 additional urban sites. "At the time of program initiation, there was widespread uncertainty that complex, long-term HIV care could be delivered in a setting with so few physicians and so little physical and technical resources," the authors write.........

Posted by: Mark      Permalink         Source


August 10, 2006, 7:01 AM CT

Never marrieds has highest risk of early death

Never marrieds has highest risk of early death
People who never marry have the greatest chance of an earlier death, reveals a study in the Journal of Epidemiology and Community Health.

The findings are based on national census and death certification data, involving almost 67,000 adults in the USA between 1989 and 1997.

In 1989, almost one in two of the sample were married, and almost one in 10 were widowed. Around 12% were divorced and 3% were separated. Of the remainder, 5% were cohabiting, and one in five had never been married.

Unsurprisingly, older age and poor health were the strongest predictors of death by 1997, but a surviving marriage was also strongly linked to a longer life.

After taking into account age, state of health, and several other factors likely to influence the findings, those who had been widowed were almost 40% more likely to die between 1989 and 1997. Those who had been divorced or separated were 27% more likely to have done so.

But those who had never been married were 58% more likely to have died during this period than their peers who were married and living with their spouse in 1989.

The never married "penalty" was larger for those in very good or excellent health, and smallest for those in poor health, and it was greater among men than women.........

Posted by: JoAnn      Permalink         Source


August 9, 2006, 11:21 PM CT

Blocking Human HIV Transmissions

Blocking Human HIV Transmissions
As primates evolved 7 million years ago, the more advanced species stopped making a protein that University of Central Florida scientists believe can effectively block the HIV-1 virus from entering and infecting blood cells.

HIV-1 often mutates quickly to overcome antiviral compounds designed to prevent infections. But a research team led by Associate Professor Alexander Cole of UCF's Burnett College of Biomedical Sciences has demonstrated that over 100 days the virus develops only weak resistance to retrocyclin, a defense peptide still found in monkeys and lower primates.

If additional laboratory tests demonstrate only weak resistance, Cole will study how retrocyclin could be developed into a drug designed to prevent the HIV virus from entering human cells.

Cole is also working with Henry Daniell, a UCF professor of molecular biology and microbiology, to develop a way to grow retrocyclin through genetically engineered tobacco plants. The retrocyclin gene would be incorporated into the chloroplast genome of tobacco cells before the plants grow. Daniell has developed a similar approach to growing anthrax vaccine in tobacco plants.

An inexpensive way to produce the drug with only a small amount of tobacco would help to make it accessible in areas such as Southeast Asia, Africa and the Caribbean where the disease spreads most quickly.........

Posted by: Mark      Permalink         Source


August 9, 2006, 10:16 PM CT

Antioxidants against tick-borne illness

Antioxidants against tick-borne illness Ixodid tick
For hikers, campers and others who enjoy the outdoors, summer can bring concerns about tick bites and related illnesses such as Rocky Mountain spotted fever. Scientists are investigating the role that antioxidants -- alpha-lipoic acid and potentially others like green tea and vitamins C and E, for example might play in preventing or treating the deadly rickettsia bacteria.

The National Institute of Allergy and Infectious Disease, part of the National Institutes of Health, awarded the University of Rochester Medical Center $2 million for a five-year study of the antioxidant theory. The grant caps more than a decade of rickettsia research led by Sanjeev Sahni, Ph.D.

Rocky Mountain spotted fever is the most frequently reported illness in the United States caused by the rickettsia bacteria, which is transmitted by tick parasites. It commonly afflicts otherwise healthy adults and children who are bitten by wood ticks or dog ticks. The illness can become life threatening if left untreated, and spotted fever can be difficult for physicians to diagnose because the earliest signs mimic less-serious viral illnesses. Limiting exposure to ticks is the best way to prevent the disease. If it does develop, in most cases doctors can treat it with antibiotics. Typhus is another rickettsial disease spread by lice or fleas. Eventhough less common, typhus remains a threat in crowded jails and in other poor hygienic environments.........

Posted by: Mark      Permalink         Source


August 2, 2006, 11:29 PM CT

First Treatment For Drug-resistant HIV

First Treatment For Drug-resistant  HIV
Doctors have their first FDA-approved tool to treat drug-resistant HIV thanks to a new molecule created by a Purdue University researcher.

"There are a number of therapys for AIDS on the market, but none are able to combat drug resistance," said Arun Ghosh (pronounced A-rune GO-sh), a professor with a dual appointment in the departments of chemistry and medicinal chemistry and molecular pharmacology. "This is the first therapy that is effective against the growing number of drug-resistant strains of HIV, the virus that causes AIDS. The problem is widespread".

The FDA recently approved the pill-based treatment of Ghosh's molecule, TMC-114, for medical use. The molecule, also known as Darunavir (pronounced DA-rune-a-veer), is the forerunner in a series of molecules under development by Ghosh.

Earlier research shows that almost half of patients with the human immunodeficiency virus (HIV) who initially respond to therapy develop drug-resistant strains and stop responding to therapy within eight to 10 months, he said. An additional 20 percent to 40 percent of patients have drug-resistant strains when they are first diagnosed, suggesting these strains can be transmitted from one person to the next.

This year marks the 25th anniversary of the first reported U.S. cases of AIDS, a disease that claims the lives of more than 15,000 Americans each year, as per the Centers for Disease Control and Prevention. World Health Organization figures estimate more than 40 million people worldwide are infected with HIV.........

Posted by: Mark      Permalink         Source


July 31, 2006, 6:56 AM CT

HIV hides from drugs

HIV hides from drugs
UC Davis scientists have discovered that the human immunodeficiency virus, the virus that causes AIDS, is able to survive efforts to destroy it by hiding out in the mucosal tissues of the intestine. They also observed that HIV continues to replicate in the gut mucosa, suppressing immune function in patients being treated with antiretroviral treatment--even when blood samples from the same individuals indicated the therapy was working. Results of the three-year study appear in the August issue of the Journal of Virology (available online today at http://jvi.asm.org).

"This is the first longitudinal study to show that, while current HIV treatment is quite successful in reducing viral loads and increasing T-cells in peripheral blood, it is not so effective in gut mucosa," said Satya Dandekar, professor and chair of the Department of Medical Microbiology and Immunology at UC Davis Health System and senior author of the study.

"The real battle between the virus and exposed individuals is happening in the gut immediately after viral infection," she said. "We need to be focusing our efforts on improving therapy of gut mucosa, where massive destruction of immune cells is occurring. Gut-associated lymphoid tissue accounts for 70 percent of the body's immune system. Restoring its function is crucial to ridding the body of the virus".........

Posted by: Mark      Permalink         Source


July 28, 2006, 10:03 PM CT

Peaks And Troughs Of Dengue Epidemics

Peaks And Troughs Of Dengue Epidemics
Researchers have long known that epidemics of dengue fever wax and wane over a period of several years, but they've never been quite sure why. With the incidence and range of the potentially deadly mosquito-borne illness increasing, understanding the factors that influence these epidemics has never been more important.

A new study by scientists at the University of Georgia suggests that a brief period of cross-immunity conferred by any one of the four viral strains, or serotypes, that cause dengue explains the timing of epidemics.

"We observed that since about the mid 1980s, there's been a sequential replacement of the dominant serotype," said lead author Helen Wearing, a post-doctoral researcher at the UGA Institute of Ecology. "So, for example, one year serotype three is 60 percent of the cases and the next year serotype two is dominant and so on. Epidemics of individual serotypes recur every eight to 10 years, but, at the same time, if you look at all the data together, you see about an average three-year cycle with some seasonal component to it".

In addition to helping resolve a long-standing debate in public health, the study, published this week in the early online edition of the journal Proceedings of the National Academy of Sciences, gives scientists a framework that can be used to create models that predict dengue outbreaks in both space and time.........

Posted by: Mark      Permalink         Source


July 26, 2006, 5:28 PM CT

Human Behavior Changes Infectious Diseases

Human Behavior Changes Infectious Diseases
Simple models predict that only one strain of an infectious disease can exist at one time, but observation suggests otherwise. In a study in the recent issue of The American Naturalist, Ken Eames and Matt Keeling (University of Warwick) use a mathematical model to help explain multiple strains, showing that the way humans interact is all-important. The scientists observed that the coexistence of multiple infectious disease strains result from monogamous populations.

"When people are serially monogamous (that is, interactions take place one at a time), groups with different behavior favor strains with different properties," explain the authors. "When new interactions occur frequently, rapidly transmitted strains are most successful, but when new interactions take place infrequently there is extra pressure on strains to have a long infectious period".

Eames and Keeling focused their study on sexually transmitted infections, where the assumption of monogamy is most applicable, but stress that their conclusions may have wider relevance.

"There are implications for all sorts of other infections too," Eames continues. "Just think of the behavioral differences between village and city life: one with quiet streets and few new faces, and the other with thousands of hurrying people and crowded public transport. That's two very different environments for a pathogen. There are always going to be plenty of factors that determine which strains emerge, but human mixing behavior has a big part to play".........

Posted by: Mark      Permalink         Source



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Did you know?
Scientists at Baylor College of Medicine in Houston have found a genetic marker that may identify individuals at greater risk for life-threatening infection from the West Nile virus. Results of the study are reported in the Nov. 15 print edition of Journal of Infectious Diseases.

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