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March 4, 2010, 9:50 PM CT

Epstein-Barr virus and multiple sclerosis

Epstein-Barr virus and multiple sclerosis
Scientists from the Harvard School of Public Health, Walter Reed Army Institute of Research, and a team of collaborators have observed for the first time that the risk of multiple sclerosis (MS) increases by a number of folds following infection with the Epstein-Barr virus (EBV). This finding implicates EBV as a contributory cause to multiple sclerosis. The study appears in an advance online edition of the journal Annals of Neurology and will appear in a later print edition.

Hundred of thousands of individuals not infected with EBV were followed up for several years through repeated blood samples collections. Scientists were then able to determine the time when individuals developed an EBV infection and its relation to MS onset. "The recruitment of individuals before they were infected with EBV and following up with them for several years is the critical methodological aspect that makes this study qualitatively different from all prior work," said Alberto Ascherio, senior author of the study and professor of epidemiology and nutrition at Harvard School of Public Health and professor of medicine at Harvard Medical School.

MS is a chronic degenerative disease of the central nervous system. Women are more likely than men to get the disease and it is the most common neurologically disabling disease in young adults. Eventhough genetic predisposition plays an important role in determining susceptibility, past studies have shown that environmental factors are equally important.........

Posted by: Daniel      Read more         Source


February 18, 2010, 9:13 PM CT

How malaria parasite spread?

How malaria parasite spread?
Infected human red blood cells (top; and right of center) by the human malaria parasite, Plasmodium falciparum (the parasite is shown in purple). The newly-formed parasites (left of center) are ready to invade new red blood cells.

Credit: Le Roch lab, UC Riverside.

Malaria remains one of the most deadly infectious diseases. Yet, how Plasmodium, the malaria parasite, regulates its infectious cycle has remained an enigma despite decades of rigorous research.

But now a research team led by a cell biologist at the University of California, Riverside has identified a mechanism by which Plasmodium intensively replicates itself in human blood to spread the disease.

"If this mechanism can be stopped," said Karine Le Roch, an assistant professor of cell biology and neuroscience, who led the research, "Plasmodium replication would cease or be severely inhibited, thus controlling the spread of malaria".

In the cells of eukaryotes, such as the unicellular Plasmodium and humans, DNA, which can be as long as two meters, is closely packed to fit into the cell's tiny nucleus. Huge complex proteins called nucleosomes facilitate this DNA compaction so that eventually the DNA is coiled in an ordered manner to form chromosomes.

Made up of histone, a kind of protein, the nucleosomes are repeating units around which the double helix of DNA gets wrapped and vast amounts of genetic information get organized.

In trying to understand how the malaria parasite multiplies in red blood cells, Le Roch's team observed that in Plasmodium a kind of "histone crash" takes place a massive breakdown of histone that explains how the parasite can replicate extensively its DNA and coding gene in human red blood cells.........

Posted by: Mark      Read more         Source


February 17, 2010, 7:28 AM CT

Influenza vaccines in elderly

Influenza vaccines in elderly
Evidence for the safety and efficacy of influenza vaccines in the over 65s is poor, despite the fact that vaccination has been recommended for the prevention of influenza in older people for the past 40 years. These are the conclusions of a new Cochrane Systematic Review.

Adults aged 65 and over are some of the most vulnerable during influenza season and a priority for vaccination programmes. However, very few systematic reviews of the effectiveness of vaccines in this group have ever been carried out.

The scientists conducted a thorough search of studies based on prior vaccine trials. Randomised controlled trials (RCTs) are often considered the "gold standard", but of the 75 studies included in their review, the scientists were only able to identify one recent RCT with "real" outcomes. In other words, this was the only RCT that used influenza cases as an outcome, as opposed to surrogate outcomes such as measurements of influenza antibodies in the blood. All the other studies included in the review were deemed of low quality and open to bias.

Limited reliable evidence from the studies suggests that the effectiveness of influenza vaccines is modest at best. "Our estimates are consistently below those commonly quoted by economists and in decision making," says lead researcher Tom Jefferson of the Cochrane Collaboration in Rome, Italy. "But until we have all available evidence, it is hard to reach any clear conclusions about the effectiveness of influenza vaccines in older people".........

Posted by: Mark      Read more         Source


February 8, 2010, 8:10 AM CT

Energy Released From a Virus During Infection

Energy Released From a Virus During Infection
Within a virus's tiny exterior is a store of energy waiting to be unleashed. When the virus encounters a host cell, this pent-up energy is released, propelling the viral DNA into the cell and turning it into a virus factory. For the first time, Carnegie Mellon University physicist Alex Evilevitch has directly measured the energy linked to the expulsion of viral DNA, a pivotal discovery toward fully understanding the physical mechanisms that control viral infection and designing drugs to interfere with the process.

"We are studying the physics of viruses, not the biology of viruses," said Evilevitch, associate professor of physics in the Mellon College of Science at Carnegie Mellon. "By treating viruses as physical objects, we can identify physical properties and mechanisms of infection that are common to a variety of viruses, regardless of their biological makeup, which could lead to the development of broad spectrum antiviral drugs".

Current antiviral medications are highly specialized. They target molecules essential to the replication cycle of specific viruses, such as HIV or influenza, limiting the drugs' use to specific diseases. Additionally, viruses mutate over time and appears to become less susceptible to the medication. Evilevitch's work in the burgeoning field of physical virology stands to provide tools for the rational design of less-specialized antiviral drugs that will have the ability to treat a broad range of viruses by interrupting the release of viral genomes into cells.........

Posted by: Mark      Read more         Source


February 1, 2010, 7:42 AM CT

HIV researchers solve key puzzle

HIV researchers solve key puzzle
Scientists have made a breakthrough in HIV research that had eluded researchers for over 20 years, potentially leading to better therapys for HIV, as per a research findings published recently in the journal Nature

The researchers, from Imperial College London and Harvard University, have grown a crystal that reveals the structure of an enzyme called integrase, which is found in retroviruses like HIV. When HIV infects someone, it uses integrase to paste a copy of its genetic information into their DNA.

Previous to the newly released study, which was funded by the Medical Research Council and the US National Institutes of Health, a number of scientists had tried and failed to work out the three-dimensional structure of integrase bound to viral DNA. New antiretroviral drugs for HIV work by blocking integrase, but researchers did not understand exactly how these drugs were working or how to improve them.

Scientists can only determine the structure of this kind of molecular machinery by obtaining high quality crystals. For the newly released study, scientists grew a crystal using a version of integrase borrowed from a little-known retrovirus called Prototype Foamy Virus (PFV). Based on their knowledge of PFV integrase and its function, they were confident that it was very similar to its HIV counterpart.........

Posted by: Mark      Read more         Source


January 27, 2010, 8:17 AM CT

Proper vaccine refrigeration vital

Proper vaccine refrigeration vital
Every year, billions of dollars worth of vaccines are shipped to thousands of medical providers across the country, and every year doctors must dispose of tens of millions of dollars worth of those vaccines because they became too warm or too cold while in storage. Now, scientists at the National Institute of Standards and Technology (NIST), with funding from and in collaboration with the Centers for Disease Control and Prevention (CDC), have completed the first of a series of tests to determine best practices for properly storing and monitoring the temperature of refrigerated vaccines.

Their initial findings* will be included in a CDC training video and report to be released July 2010.

To ensure they are effective, most vaccines must be kept between 2 and 8 degrees Celsius from the time they are manufactured until they are administered. In addition to the cost of spoiled vaccines that must be destroyed, lack of temperature control probably has resulted in the administering of ineffective vaccinations to the public in a small, but significant, percentage of cases.

In this first phase of a larger study, NIST scientists compared standard-sized refrigerators without freezers against smaller, dormitory-style refrigerators under a variety of conditions, storage practices and use scenarios, including leaving the refrigerator door ajar for various periods, power loss and raising the ambient temperature of the room.........

Posted by: Mark      Read more         Source


January 27, 2010, 8:16 AM CT

Ffighting the deadly staph infection

Ffighting the deadly staph infection
Scientists at the University of Illinois at Chicago and Israel's Weizman Institute of Science have observed that two antibiotics working together might be more effective in fighting pathogenic bacteria than either drug on its own.

Individually, lankacidin and lankamycin, two antibiotics produced naturally by the microbe streptomyces, are marginally effective in warding off pathogens, says Alexander Mankin, professor and associate director of the UIC Center for Pharmaceutical Biotechnology and lead investigator of the portion of the study conducted at UIC.

Mankin's team observed that when used together, the two antibiotics are much more successful in inhibiting growth of dangerous pathogens such as MRSA, or methicillin-resistant Staphylococcus aureus, and possibly others.

MRSA is a staph infection that is resistant to certain antibiotics. As per a 2007 government report, more than 90,000 Americans get potentially deadly infections each year.

The research results are reported in the Jan. 11 online edition of the Proceedings of the National Academy of Sciences of the USA.

Lankacidin and lankamycin act upon the ribosomes, the protein-synthesizing factories of the cell. A newly-made protein exits the ribosome through a tunnel through the ribosome body. Some antibiotics stave off an infection by preventing the ribosome from assembling proteins, while others bind in the tunnel and block the protein's passage.........

Posted by: Mark      Read more         Source


January 26, 2010, 8:54 AM CT

CT to diagnose appendicitis

CT to diagnose appendicitis
Preoperative computed tomography (CT) may help reduce unnecessary surgeries in women of reproductive age with suspected acute appendicitis, as per a newly released study appearing in the recent issue of the journal Radiology

"We observed that rising utilization of preoperative CT over the past decade, along with advances in CT technology, coincided with a significant decrease in negative appendectomies among women 45 years and younger," said Courtney A. Coursey, M.D., a radiologist at Emory University in Atlanta, who co-authored this study while a radiology fellow at Duke University Medical Center in Durham, N.C.

Acute appendicitis is inflammation of the appendix, a fingerlike organ attached to the large intestine in the lower right area of the abdomen. An inflamed appendix can perforate, resulting in a life-threatening infection.

While surgical removal of the appendix is the common therapy for acute appendicitis, diagnosis is not always clear clinically. Previous to the advent of CT, in inconclusive cases, physicians would often remove the appendix as a precaution. Historically, this resulted in a high rate of negative appendectomies with negative appendectomy rates of 20 percent to 25 percent and as high as 40 percent in women considered acceptable. Negative appendectomy rates are generally higher in women due to gynecologic pathology that can confound appendicitis diagnosis. For instance, symptomatic ovarian cysts can cause lower abdominal pain similar to that from appendicitis.........

Posted by: Mark      Read more         Source


January 22, 2010, 8:20 AM CT

Face Masks and Hand Hygiene

Face Masks and Hand Hygiene
Ordinary face masks and hand hygiene can effectively reduce the transmission of influenza-like illness during flu season. The finding comes from a newly released study, now available online, reported in the Feb. 15 issue of The Journal of Infectious Diseases. In an influenza pandemic, vaccination may not be initially available, and antiviral prescribing appears to be limited, which is why researchers need to understand how effective other measures are in preventing influenza.

For the study, scientists from the University of Michigan School of Public Health, led by Allison E. Aiello, PhD, recruited more than 1,400 college students living in university residence halls during the 2006-2007 influenza season. Participants were assigned to one of three groups: those who wore face masks, those who wore masks and used alcohol-based hand sanitizer, or a control group who received no intervention. Students were monitored for influenza-like symptoms for six weeks. All participants viewed a basic hand hygiene instructional video. Subjects in the hand hygiene and mask group were given an alcohol-based hand sanitizer and written instructions regarding proper face mask and hand sanitizer use. Those in the mask group received written instructions on face mask use only. The students began using the measures just after laboratory confirmation of influenza on the University of Michigan campus had been made.........

Posted by: Mark      Read more         Source


January 21, 2010, 8:20 AM CT

Herpes medication does not reduce risk of HIV transmission

Herpes medication does not reduce risk of HIV transmission
A five-year international multi-center clinical trial has observed that acyclovir, a drug widely used as a safe and effective therapy taken twice daily to suppress herpes simplex virus-2 (HSV-2), which is the most common cause of genital herpes, does not reduce the risk of HIV transmission when taken by people infected with both HIV and HSV-2. The results of the study are reported in the New England Journal (NEJM) online today, and will appear in the Feb. 4, 2010 issue of the publication.

Up to 90% of people with HIV infection also have HSV-2 infection. Most people who are infected with HSV-2 do not know they have the virus because symptoms can be mild or absent. HSV-2 infection can cause recurrent sores and breaks in the skin of the genital region, which can be mild and often go unnoticed. HSV-2 infection also attracts immune cells called CD4 T-cells to the genital region, which HIV uses to establish or pass infection.

Multiple studies have shown that frequent genital herpes recurrences increase the amount of HIV in the blood and genital tract. The HIV virus is also shed from genital herpes ulcers and persons with such ulcers transmit HIV to others more efficiently. Five preliminary studies showed that it is possible to decrease the amount of HIV in the blood and genital tract through therapy to suppress HSV-2, but these studies did not measure whether this translated into a reduction in HIV transmission. Scientists had hoped that acyclovir's ability to suppress the herpes virus, which causes symptomatic genital sores and breaks in the skin but also frequently is active without symptoms, could reduce the likelihood of sexual transmission of HIV from a person with HIV and HSV-2. The study is the first to determine whether twice daily use of acyclovir by individuals who are infected with both HSV-2 and HIV reduced the transmission of HIV to their sexual partners. The authors conclude that daily acyclovir treatment did not reduce the risk of transmission of HIV, in spite of the fact that acyclovir reduced plasma HIV RNA by a log and the occurrence of genital ulcers due to HSV-2 by 73%.........

Posted by: Mark      Read more         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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