February 8, 2010, 8:10 AM CT

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

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

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

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

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

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

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

January 19, 2010, 8:20 AM CT

Would you experience appendicitis?

Would you experience appendicitis?.

And if you do, is it necessarily an emergency that demands immediate surgery?

Yes and no, as per a newly released study by UT Southwestern Medical Center surgeons and physicians.

The scientists reviewed data over a 36-year period from the National Hospital Discharge Survey and concluded in a paper appearing in the recent issue of Archives of Surgery that appendicitis appears to be caused by undetermined viral infection or infections, said Dr. Edward Livingston, chief of GI/endocrine surgery at UT Southwestern and senior author of the report.

The review of hospital discharge data runs counter to traditional thought, suggesting that appendicitis doesn't necessarily lead to a burst appendix if the organ is not removed quickly, Dr. Livingston said.

"Just as the traditional appendix scar across the abdomen is fast becoming history, thanks to new single-incision surgery techniques that hide a tiny scar in the bellybutton, so too may the conventional wisdom that patients with appendicitis need to be operated on as soon as they enter the hospital," said Dr. Livingston. "Patients still need to be seen quickly by a physician, but emergency surgery is now in question".

Appendicitis is the most common reason for emergency general surgery, leading to some 280,000 appendectomies being performed annually......... Posted by: Mark      Read more         Source

January 15, 2010, 8:16 AM CT

Mechanism for the Proliferation of Epstein-Barr Virus

Researchers of Helmholtz Zentrum München have elucidated a crucial mechanism in the lytic cycle of Epstein-Barr virus. A team of scientists led by Professor Wolfgang Hammerschmidt identified the function of a protein which plays a critical role in the proliferation of the virus. The Epstein-Barr virus can induce cancer. The findings, reported in the current issue of the renowned journal PNAS, represent a major step forward in understanding tumor development.

The Epstein-Barr virus (EBV), a virus of the herpes family, has two distinct life phases: After infecting a cell it first goes into a resting phase. Under certain circumstances the virus can become active - and then induces tumor growth or promotes its synthesis in the cell. Particularly in patients with weakened immune systems, EBV can cause its host cells to divide uncontrollably - causing a tumor to develop.

The causes for the transition of EBV from the quiescent phase to an active mode - especially with respect to the responsible factors and to how the molecular mechanisms function - have until now remained elusive. With their findings, the researchers at Helmholtz Zentrum München have discovered how the virus terminates latency and activates its synthesis in the infected cells.

Professor Wolfgang Hammerschmidt, head of the Department of Gene Vectors at Helmholtz Zentrum München, explained: "We have now identified the crucial function of the viral BZLF1 protein: It activates the genes of EBV, which are essential for the proliferation of virus particles." About 70 different genes are switched off during the latent phase because certain DNA segments are chemically modified: Some DNA building blocks carry methyl groups. They are a kind of stop signal for the cell apparatus, so that these genes cannot be converted into protein......... Posted by: Mark      Read more         Source

January 14, 2010, 8:12 AM CT

Some antiviral drugs may make diseases worse

As the flu season continues in full-swing, most people can appreciate the need for drugs that stop viruses after they take hold in the body. Despite this serious need for new drugs, a team of scientists from the University of Texas at Austin raise serious concerns about an emerging strategy for stopping viral infections. As per their research report appearing in the January 2010 issue of the journal GENETICS, medications that cause viruses to die off by forcing their nucleic acid to mutate rapidly might actually, in some instances, cause them to emerge from the process stronger, perhaps even more virulent than before drug therapy.

"This work questions whether the practice of 'lethal mutagenesis' of viruses works as predicted," said Jim Bull, Ph.D., a researcher involved in the study from the Institute for Cellular and Molecular Biology at the University of Texas at Austin. "It remains to be seen whether an elevated mutation rate that does not cause rapid viral extinction enhances therapy or may instead thwart therapy by enhancing viral evolution." Bull's research collaborators included Rachael Springman, Thomas Keller, and Ian Molineux from the same institution.

Researchers tested the model of viral evolution at high mutation rates by growing a DNA virus in the presence of a mutagenic agent. The current accepted model predicted that the virus would not be able to handle the high mutation rates and would eventually die off. However, this study proved the model false, as the virus actually increased its fitness at elevated mutation rates. During this study, researchers found molecular evidence that rapid mutations had two effects. The first effect of most mutations, which was expected, was that they killed or weakened the virus. The second effect of some mutations, however, was that they actually helped the virus adapt and thrive. Eventhough the scientists did not question that extremely high mutation will lead to viral extinction on the whole, this discovery raises the specter that forcing viruses to undergo rapid mutations could, if the mutation rate is not high enough, accidentally lead to well-adapted "super viruses." ......... Posted by: Mark      Read more         Source

January 14, 2010, 7:49 AM CT

56 percent of young adults infected with HPV

A groundbreaking study of couples led by Professor Eduardo Franco, Director of McGill University's Cancer Epidemiology Unit, in collaboration with a team of colleagues from McGill and Universit de Montral/Centre Hospitalier de l'Universit de Montral (CHUM), found more than half (56 per cent) of young adults in a new sexual relationship were infected with human papillomavirus (HPV). Of those, nearly half (44 per cent) were infected with an HPV type that causes cancer.

Dr. Ann Burchell, the Project Coordinator and a former PhD student and post-doctoral fellow with Dr. Franco at the Cancer Epidemiology Unit, conducted the HITCH Cohort Study (HPV Infection and Transmission in Couples through Heterosexual activity) to determine the prevalence of HPV infections among recently formed couples. This is the first large-scale study of HPV infection among couples early in their sexual relationships when transmission is most likely.

The results, reported in the January 2010 issues of Epidemiology and Sexually Transmitted Diseases, also indicate there is a high probability of HPV transmission between partners. When one partner had HPV, the scientists found that in 42 per cent of couples, the other partner also had the infection. Moreover, the scientists observed that the presence of HPV in one partner was the strongest predictor of finding the same HPV type in the other partner. If one partner was infected with HPV, the other partner's chance of also being infected with the same HPV type increased over 50 times......... Posted by: Mark      Read more         Source

January 5, 2010, 8:40 AM CT

HIV-infected postmenopausal women

As per a newly released study accepted for publication in The Endocrine Society's Journal of Clinical Endocrinology & Metabolism (JCEM), postmenopausal HIV-infected women have a high prevalence of low bone mineral density and high bone turnover placing them at high risk for future bone fractures.

"As HIV-infected individuals live longer with potent antiretroviral treatment (ART), metabolic complications such as low bone density and osteoporosis are increasingly recognized," said Michael Yin, MD of Columbia University Medical Center in New York and main author of the study. "Eventhough numbers of HIV-infected postmenopausal women are increasing and postmenopausal women are at highest risk for osteoporotic fractures, few studies have reviewed skeletal status in this group. We hypothesized that postmenopausal women might be especially vulnerable to the adverse effects of HIV infection or ART on the skeleton and our results indicate that this may indeed be the case".

To test their hypothesis, Yin and colleagues initiated a longitudinal study to assess bone health in 92 HIV-positive and 95 HIV-negative postmenopausal women. Bone mineral density of the lumbar spine, femoral neck and hip as well as body composition were measured by dual x-ray absorptiometry (DXA). Scientists observed that HIV-positive postmenopausal women had lower bone mineral density at both the spine and hip than HIV-negative postmenopausal women......... Posted by: Mark      Read more         Source

December 24, 2009, 10:13 PM CT

New tool in the fight against mosquito-borne disease

Earlier this year, scientists showed that they could cut the lives of disease-carrying mosquitoes in half by infecting them with a bacterium they took from fruit flies. Now, a new report in the December 24th issue of Cell, a Cell Press publication, suggests that their strategy might do one better: The Wolbachia bacteria also makes the mosquitoes more resistant to infection by viruses that are a growing threat to humans, including those responsible for dengue fever and Chikungunya.

Once infected with Wolbachia, Aedes aegypti mosquitoes also become less suitable as hosts for a form of malaria parasite that infects birds, said Scott O'Neill of The University of Queensland. (The mosquitoes under study aren't natural carriers of human malaria.).

"This might be very powerful in reducing pathogen transmission by Aedes aegypti to humans, especially for dengue and Chikungunya," O'Neill said. "Together with the previously described life-shortening effects, the results suggest we might be able to have a major impact on disease." That's if it can be shown that the Wolbachia infection can invade natural mosquito populations, he added, a question his team is working on right now.

There is no vaccine or cure for dengue fever, which is a painful and debilitating disease suffered by some 50 million people worldwide every year. Dengue haemorrhagic fever, the more severe form of the disease, kills more than 40,000 people annually. Chikungunya commonly isn't fatal, but can cause symptoms similar to dengue. Human epidemics of Chikungunya have been cited in Africa, Asia and more recently in Europe, as per the CDC......... Posted by: Mark      Read more         Source

December 23, 2009, 8:04 AM CT

New, virulent strain of MRSA

The often feared and sometimes deadly infections caused by MRSA - methicillin-resistant Staphylococcus aureus - are now moving out of hospitals and emerging as an even more virulent strain in community settings and on athletic teams, and raising new concerns about antibiotic resistance.

Right now, the new community-associated strain of MRSA is responsive to more, but sometimes different antibiotics than its hospital relative, experts say. But those antibiotics will almost certainly lose their effectiveness as they are used more widely, and efforts are under way to combat that issue.

A newly released study by pharmacy scientists at Oregon State University has identified two antibiotics that appear less likely to cause future antibiotic resistance, and others that if used would allow resistance to emerge more quickly. This analysis, just reported in the International Journal of Antimicrobial Agents, offers physicians some direction to help deal with this problem until more research can be done, they said.

"The problem with invasive MRSA infections is very real and is now moving from the hospital setting to the community," said George Allen, an assistant professor in the OSU College of Pharmacy. "The community-based strain in some ways is even more apt to cause serious problems than those most often acquired in hospitals, and increasing quite dramatically in prevalence......... Posted by: Mark      Read more         Source

December 23, 2009, 7:57 AM CT

Nanotechnology Heals Abscesses

Scientists at Albert Einstein College of Medicine of Yeshiva University have developed a new approach for treating and healing skin abscesses caused by bacteria resistant to most antibiotics. The study appears in the journal PLoS One.

Abscesses are deep skin infections that often resist antibiotics and may require surgical drainage. For their new therapy strategy, the Einstein researchers developed tiny nanoparticles - smaller than a grain of pollen - that carry nitric oxide (NO), a gas that helps in the body's natural immune response to infection.

When topically applied to abscesses in mice, the particles released NO that traveled deep into the skin, clearing up the infections and helping to heal tissue.

"Our work shows that nitric oxide-releasing nanoparticles developed here at Einstein can effectively treat experimental skin abscesses caused by antibiotic-resistant Staphylococcus aureus, even without surgical drainage," says Joshua D. Nosanchuk, M.D., senior author of the study and associate professor of medicine and of microbiology & immunology.

"This is important," he notes, "because several million people are treated for staph infections every year in the U.S. Increasingly, these infections are caused by methicillin-resistant Staph aureus - or MRSA - the serious and potentially fatal "superbug" that we tackled in this study"......... Posted by: Mark      Read more         Source

December 10, 2009, 11:09 PM CT

Biological Route for Swine Flu to Human

A new biological pathway by which the H1N1 flu virus can make the jump from swine to humans has been discovered by scientists with the U.S. Department of Energy's Lawrence Berkeley National Laboratory (Berkeley Lab) and the University of California, Berkeley. Early test results indicate that a heretofore unknown mutation in one of the H1N1 genes may have played an important role in transmitting the virus into humans.

"Transmission of influenza viruses into the human population requires surmounting biological barriers to cross-species infection," says biochemist Jennifer Doudna, the principal investigator for this research. "We have identified an adaptive mutation in the swine origin H1N1 influenza A virus - a pair of amino acid variants termed the 'SR polymorphism' - that enhance replication, and potentially pathogenesis of the virus in humans".

Doudna, an authority on RNA molecular structures, holds joint appointments with Berkeley Lab's Physical Biosciences Division, and UC Berkeley's Department of Molecular and Cell Biology and Department of Chemistry. She's also an investigator with the Howard Hughes Medical Institute (HHMI). She and Andrew Mehle, a post-doctoral fellow in her research group, have published a paper on this research in the Proceedings of the National Academy of Sciences (PNAS) titled: Adaptive strategies of the influenza virus polymerase for replication in humans"......... Posted by: Mark      Read more         Source

November 18, 2009, 11:36 PM CT

Why hepatitis is harder on men?

Researchers in China are reporting discovery of unusual liver proteins, found only in males, that may help explain the long-standing mystery of why the hepatitis B virus (HBV) sexually discriminates -- hitting men harder than women. Their study has been published online in ACS' Journal of Proteome Research, a monthly publication.

Shuhan Sun, Fang Wang and his colleagues note that chronic hepatitis B seems to progress and cause liver damage faster in men, with men the main victims of the virus's most serious complications -- cirrhosis and liver cancer. Men infected with HBV also are 6 times more likely than women to develop a chronic form of the disease. About 400 million people worldwide have chronic hepatitis B, including a form that is highly infectious and can be transmitted through blood, saliva, and sexual contact.

In experiments with laboratory mice, the researchers found abnormal forms of apolipoprotein A-I (Apo A-I), a protein involved in fighting inflammation, in the livers of infected male mice but not infected females. They then identified abnormal forms of these Apo A-I proteins in blood of men infected with HBV, but not in women. In addition to explaining the gender differences, the proteins may provide important markers for tracking the progression of hepatitis B, the researchers suggest......... Posted by: Mark      Read more         Source