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January 15, 2009, 6:26 PM CT

New class of antibiotics

New class of antibiotics
As bacteria resistant to usually used antibiotics continue to increase in number, researchers keep searching for new sources of drugs. In this week's JBC, one potential new bactericide has been found in the tiny freshwater animal Hydra.

The protein identified by Joachim Grtzinger, Thomas Bosch and his colleagues at the University of Kiel, hydramacin-1, is unusual (and also clinically valuable) as it shares virtually no similarity with any other known antibacterial proteins except for two antimicrobials found in another ancient animal, the leech.

Hydramacin showed to be very effective though; in a series of laboratory laboratory tests, this protein could destroy a wide range of both Gram-positive and Gram-negative bacteria, including clinically-isolated drug-resistant breeds like Klebsiella oxytoca (a common cause of nosocomial infections). Hydramacin works by adhering to the bacterial surface, promoting the clumping of nearby bacteria, then disrupting the bacterial membrane.

Grtzinger and his team also determined the 3-D shape of hydramacin-1, which revealed that it most closely resembled a superfamily of proteins found in scorpion venom; within this large group, they propose that hydramacin and the two leech proteins are members of a newly designated family called the macins.........

Posted by: Mark      Read more         Source


January 12, 2009, 11:46 PM CT

If you sleep less you catch cold

If you sleep less you catch cold
Individuals who get less than seven hours of sleep per night appear about three times as likely to develop respiratory illness following exposure to a cold virus as those who sleep eight hours or more, as per a report in the January 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Studies have demonstrated that sleep deprivation impairs some immune function, as per background information in the article. Research indicates that those who sleep approximately seven to eight hours per night have the lowest rates of heart disease illness and death. However, there has previously been little direct evidence that poor sleep increases susceptibility to the common cold.

Sheldon Cohen, Ph.D., of Carnegie Mellon University, Pittsburgh, and his colleagues studied 153 healthy men and women (average age 37) between 2000 and 2004. Participants were interviewed daily over a two-week period, reporting how a number of hours they slept per night, what percentage of their time in bed was spent asleep (sleep efficiency) and whether they felt rested. They were then quarantined and administered nasal drops containing the common-coldcausing rhinovirus. For five days afterward, the study participants reported any signs and symptoms of illness and had mucus samples collected from their nasal passages for virus cultures; about 28 days later, they submitted a blood sample that was tested for antibody responses to the virus.........

Posted by: Mark      Read more         Source


January 12, 2009, 11:40 PM CT

New weapon in battle against HIV infection?

New weapon in battle against HIV infection?
Scientists have discovered a potentially important new resistance factor in the battle against HIV: blood types. An international team of scientists from Canadian Blood Services, The Hospital for Sick Children (SickKids) and Lund University in Sweden have discovered that certain blood types are more predisposed to contracting HIV, while others are more effective at fending it off.

A carbohydrate-containing antigen, termed Pk blood group which is distinct from the well-known ABO and Rh blood grouping systems, is present at variable levels on the surface of white and red blood cells in the general population. A study published recently in Blood, which is currently available online, shows that cells from rare individuals (≈ 1 in a million) who produce excess of this blood group antigen have dramatically reduced sensitivity to HIV infection. On the other hand, another slightly more common subgroup of people who do not produce any Pk (≈ 5 in a million) was found to be much more susceptible to the virus.

"This study is not suggesting that your blood type alone determines if you will get HIV," says main author Dr. Don Branch of Canadian Blood Services. "However, it does suggest that individuals who are exposed to the virus, appears to be helped or hindered by their blood status in fighting the infection".........

Posted by: Mark      Read more         Source


January 8, 2009, 7:59 PM CT

What drives one of nature's powerful, nanoscale motors

What drives one of nature's powerful, nanoscale motors
Image of DNA entering the gp17 motor complex on the T4 capsid.

Credit: T4:2 - Motor Packing, © 2008 Seyet LLC
Peering at structures only atoms across, scientists have identified the clockwork that drives a powerful virus nanomotor.

Because of the motor's strength--to scale, twice that of an automobile--the new findings could inspire engineers designing sophisticated nanomachines. In addition, because many virus types may possess a similar motor, including the virus that causes herpes, the results may also assist pharmaceutical companies developing methods to sabotage virus machinery.

Scientists from Purdue University in West Lafayette, Ind., and the Catholic University of America in Washington, D.C., collaborated on the study that appears in the Dec. 26, 2008, issue of the journal Cell.

"The discovery of how this virus motor functions represents a significant milestone in the investigation of viral processes," says David Rockcliffe, the program director who oversees a National Science Foundation (NSF) grant that partly funded the research. "This research is a breakthrough that not only may lead to the development of a means of arresting harmful infections, but it also points to possible ways in which nano-devices could be fashioned,".

The virus in the study, called T4, is not a common scourge of people, but its host is: the bacterium Escherichia coli (E. coli). Purdue scientists studied the virus structures, such as the motor, while the Catholic University scientists isolated the virus components and performed biochemical analyses.........

Posted by: Mark      Read more         Source


January 7, 2009, 11:27 PM CT

More Resistant Avian Flu Virus

More Resistant Avian Flu Virus
Researchers using Google Earth technology are able to visually chart individual outbreaks of the avian flu as it has spread outward from China over the past decade, including gene mutations that are causing a resistance to a major class of antiviral drugs.

Credit: Google Earth, University of Colorado

A new University of Colorado at Boulder study shows the resistance of the avian flu virus to a major class of antiviral drugs is increasing through positive evolutionary selection, with scientists documenting the trend in more than 30 percent of the samples tested.

The avian flu, an Influenza A subtype dubbed H5N1, is evolving a resistance to a group of antiviral drugs known as adamantanes, one of two classes of antiviral drugs used to prevent and treat flu symptoms, said CU-Boulder doctoral student Andrew Hill, lead study author. The rise of resistance to adamantanes -- which include the nonprescription drugs amantadine and rimantadane -- may be associated with Chinese farmers adding the drugs to chicken feed as a flu preventative, as per a 2008 paper by scientists from China Agricultural University, said Hill.

In contrast, resistance of the avian flu virus to the second, newer class of antiviral drugs that includes oseltamivir -- a prescription drug marketed under the brand name Tamiflu -- is present, but is still not prevalent or under positive genetic selection, said Hill of CU-Boulder's ecology and evolutionary biology department. The CU findings should help health administrators around the world plan for the possibility of an avian flu pandemic.

The CU-Boulder study is the first to show H5N1 drug resistance to adamantanes arose through novel genetic mutations rather than an exchange of RNA segments within cells, a process known as re-assortment, said Hill. The research on the mutations, combined with molecular evolution tests and a geographic visualization technique using Google Earth, "provides a framework for analysis of globally distributed data to monitor the evolution of drug resistance," said Hill.........

Posted by: Mark      Read more         Source


December 22, 2008, 9:19 PM CT

Medical lessons from cell phones

Medical lessons from cell phones
Cell phones have already revolutionized the way people around the world communicate and do business. Thanks to advances being made at UCLA, they are about to do the same thing for medicine.

In the lab of UCLA electrical engineering professor Aydogan Ozcan, a prototype cell phone has been constructed that is capable of monitoring the condition of HIV and malaria patients, as well as testing water quality in undeveloped areas or disaster sites. The innovative imaging technology was invented by Ozcan, a member of the California NanoSystems Institute at UCLA, and has been miniaturized by scientists in his lab to the point that it can fit in standard cell phones.

The imaging platform, known as LUCAS (Lensless Ultra-wide-field Cell monitoring Array platform based on Shadow imaging), has now been successfully installed in both a cell phone and a webcam. Both devices acquire an image in the same way, using a short wavelength blue light to illuminate a blood, saliva or other fluid sample. LUCAS captures an image of the microparticles in the solution using a sensor array.

Because red blood cells and other microparticles have a distinct diffraction pattern, or shadow image, they can be identified and counted virtually instantaneously by LUCAS using a custom-developed "decision algorithm" that compares the captured shadow images to a library of training images. Data collected by LUCAS can then be sent to a hospital for analysis and diagnosis using the cell phone, or transferred via USB to a computer for transmission to a hospital.........

Posted by: Mark      Read more         Source


December 17, 2008, 10:37 PM CT

Circumcision Reduces the Risk of HIV Infection

Circumcision Reduces the Risk of HIV Infection
HIV
A new U.S. study has observed that being circumcised significantly reduced the risk of HIV infection in heterosexual African American men known to have been exposed to the virus. The findings complement those of recently reported clinical trials in Africa, where interventional use of adult male circumcision similarly reduced the risk of HIV infection in heterosexual men. The findings of the new study, along with similar results from other studies, suggest that circumcision may protect other heterosexual males in the U.S. The promising new findings are published in the January 1 issue of The Journal of Infectious Diseases, now available online.

Lee Warner, PhD, MPH, and his colleagues at the Centers for Disease Control and Prevention (CDC) and the Johns Hopkins University School of Medicine studied the records of more than 26,000 African American men who had had HIV testing during visits to two Baltimore, Maryland, STD clinics from 1993 to 2000. The subjects selected for the study said that they did not inject drugs and had sex only with women. Their visits to the clinics were classified as involving known HIV exposure if there had been a recent notification of such exposure by a sex partner or by a clinic's disease intervention specialists; clinic visits for other reasons were classified as involving unknown HIV exposure. By these criteria, the researchers found 394 visits with known exposure and 40,177 visits with unknown exposure.........

Posted by: Mark      Read more         Source


December 4, 2008, 5:24 AM CT

Interferon needed for cells to "remember" how to defeat a virus

Interferon needed for cells to
Dr. David Farrar (right) led immunology researchers, including student assistants Ann Davis (center) and Hilario Ramos, in demonstrating that the protein interferon plays a key role in "teaching" the immune system how to stave off repeated infections of the same virus.
Researchers at UT Southwestern Medical Center have determined that the immune-system protein interferon plays a key role in "teaching" the immune system how to fight off repeated infections of the same virus.

The findings, available online and in the Dec. 15 issue of the Journal of Immunology, have potential application in the development of more effective vaccines and anti-viral therapies.

Typically, when a person is infected with a virus, the human body immediately generates a massive number of T cells - a type of immune cell - that kill off the infected cells. Once the infection has cleared, most of the T cells also die off, leaving behind a small pool of central memory cells that "remember" how to fight that particular type of virus if the person is infected again.

"In this study, we have uncovered interferon's role and the key signaling protein, called IL-2, involved in generating memory T cells," said Dr. David Farrar, assistant professor of immunology at UT Southwestern and senior author of the study. "Knowing how T cells acquire this memory may help us design better strategies and vaccines to fight HIV and other infectious diseases. Further, our discovery was made using primary human CD4+ T cells, which underscores the relevance of our discovery to human immune responses".........

Posted by: Mark      Read more         Source


December 1, 2008, 6:00 PM CT

Childhood vaccines cause financial burden

Childhood vaccines cause financial burden
A young man receives a vaccination. The cost and reimbursement levels of vaccines vary widely, according to new studies from the University of Michigan Health System.

Credit: Scott Soderberg, University of Michigan

The costs that health care providers are charged and reimbursed for childhood vaccines vary widely, and the high cost of some immunizations is leading to significant financial strain for some physicians, as per a pair of new studies from the University of Michigan Health System.

The findings suggest that a number of physicians appear to be paying too much and receiving too little reimbursement, but they can use this new data to help improve both areas, the scientists say.

"Physicians need to be better business people, and negotiate better prices and payments," says lead author Gary L. Freed, M.D., MPH, chief of the Division of General Pediatrics and director of the Child Health Evaluation and Research (CHEAR) Unit at the U-M Health System's Mott Children's Hospital. Freed is the immediate past chair of the U.S. Department of Health and Human Services' National Vaccine Advisory Committee.

With vaccines for children enrolled in Medicaid funded by the public sector through the federal Vaccines for Children Program, prices are negotiated annually with vaccine manufacturers by the Centers for Disease Control and Prevention. But the data from the new studies support the belief that costs and reimbursements are widely variable in private practices.

"Until now, nobody knew what anyone was paying," Freed notes. "This information will change the way in which physicians negotiate prices." The studies appear in the recent issue of the journal Pediatrics........

Posted by: JoAnn      Read more         Source


December 1, 2008, 5:52 PM CT

Antibiotics: Single largest class of drugs causing liver injury

Antibiotics: Single largest class of drugs causing liver injury
Antibiotics are the single largest class of agents that cause idiosyncratic drug-induced liver injury (DILI), reports a new study in Gastroenterology, an official journal of the American Gastroenterological Association (AGA) Institute. DILI is the most common cause of death from acute liver failure and accounts for approximately 13 percent of cases of acute liver failure in the U.S. It is caused by a wide variety of prescription and nonprescription medications, nutritional supplements and herbals.

"DILI is a serious health problem that impacts patients, physicians, government regulators and the pharmaceutical industry," said Naga P. Chalasani, MD, of the Indiana University School of Medicine and lead author of the study. "Further efforts are needed in defining its pathogenesis and developing means for the early detection, accurate diagnosis, prevention and therapy of DILI".

In this prospective, ongoing, multi-center observational study the largest of its kind patients with suspected DILI were enrolled based upon predefined criteria and followed for at least six months. Those with acetaminophen liver injury were excluded.

Scientists observed that DILI was caused by a single prescription medicine in 73 percent of the cases, by dietary supplements in 9 percent and by multiple agents in 18 percent. More than 100 different agents were linked to DILI; antimicrobials (45.5 percent) and central nervous system agents (15 percent) were the most common. Of the dietary supplements causing DILI, compounds that claim to promote weight loss and muscle building accounted for nearly 60 percent of the cases. The study observed that at least 20 percent of patients with DILI ingest more than one potentially hepatotoxic agent.........

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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