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February 23, 2009, 10:00 PM CT

Breakthrough in HPV research

Breakthrough in HPV research
HPV
Scientists have developed a new, inexpensive and efficient method for producing and studying a type of human papillomavirus (HPV) that causes cervical cancer. The process could speed understanding of how the virus functions and causes diseases, and lead to new prevention or therapy options.

In findings reported on-line and in print in January in Genes & Development, the UAB team detailed a process for producing HPV-18 in the laboratory. Previously, the virus had proven resistant to propagation in a lab setting, making it extremely difficult for researchers to study the virus and its effects on the host cells that it infects.

"The old method for propagating papillomaviruses in the lab for study was compromised by several factors," said Louise Chow, Ph.D., professor of biochemistry and molecular genetics at UAB and a co-author of study. "We could only look at the viral DNA gene by individual gene, which gave us little insight into how the entire virus coordinated its replication program or how it interacted with the host cells and tissues that had been infected".

The new method, which Chow and co-author of study Thomas Broker, Ph.D., professor of biochemistry and molecular genetics, have been developing for over 20 years, for the first time allows scientists to reproduce the entire infection cycle of HPV-18 in primary human skin cells, called keratinocytes. The breakthrough is the result of several years of intensive and creative efforts by graduate students Hsu-Kun (Wayne) Wang and Aaron Duffy, coauthors of the publication. Researchers now can observe how the virus behaves in the same cells it would infect in a human body.........

Posted by: Mark      Read more         Source


February 20, 2009, 6:18 AM CT

Bacteria with burglar's tools

Bacteria with burglar's tools
Differences in the way they use their genes cause different strains of the E. coli bacterium to take on different hues. The beaker in the foreground contains strains of bacteria linked to urinary tract infections, while the background beaker holds more benign strains of bacteria isolated from the gut. Scientists are hoping to develop drugs that specifically target infection-causing strains of bacteria like those in the foreground beaker.

Credit: Michael Purdy/Washington University School of Medicine in St. Louis

Bacteria that cause urinary tract infections (UTIs) make more tools for stealing from their host than friendly versions of the same bacteria found in the gut, scientists at Washington University School of Medicine in St. Louis and the University of Washington have found.

The tools, compounds called siderophores, allow the bad bacteria to steal iron from their hosts, making it easier for the bacteria to survive and reproduce. But they also provide a potential way to target the bad strains of bacteria for eradication without adversely affecting the good strains, scientists report as per a research findings published online Feb. 20 by PLoS Pathogens

"When we treat an infection with antibiotics, it's like dropping a bombnearly everything gets wiped out, regardless of whether it's helpful or harmful," says main author Jeff Henderson, M.D., Ph.D., a Washington University infectious disease specialist who treats patients with UTIs at Barnes-Jewish Hospital. "We'd like to find ways to target the bad bacteria and leave the good bacteria alone, and these siderophores are a great lead in that direction".

UTIs are one of the most common infections, causing around $1.6 billion in medical expenses every year in the United States. Half of all women will experience a UTI at some point in their lives, and recurrent UTIs affect 20 to 40 percent of these patients. Researchers believe 90 percent of all UTIs are caused by the bacterium Escherichia coli (E. coli).........

Posted by: Mark      Read more         Source


February 20, 2009, 5:58 AM CT

Source of germs

Source of germs
The recent salmonella outbreak associated with 575 illnesses and eight deaths across 43 states was shown to come from a dirty peanut processing plant in Georgia. And while it is essential for food processing plants to be clean and sanitary, Temple public health professor Jennifer Ibrahim, Ph.D., says officials need to consider other possible sources of illness.

"Right now, all of the focus is on the state of the peanut processing plant, but no one is really looking at the bigger picture where else can illness be passed along to the food?" she said.

In a report reported in the recent issue of the Journal of Environmental Health, Ibrahim specifically highlights farm workers themselves those who handle the food before it even gets to the plants as another potential source for food borne illness.

"Farm workers tend to be a transitory group, so you might have someone working in the field who hasn't been doing this for very long, and might not be aware that what they're doing can be harmful," said Ibrahim.

She adds that farm workers aren't mandatory to be vaccinated, which presents an increased threat for the spread of disease, especially among foods that do not require cooking.

"The current food safety system is very reactive in that policies aren't really looked at until a major event happens," said Ibrahim. "But how often do you hear about friends or family having a bout of food poisoning? It highlights a need to be proactive and re-evaluate the processes of the FDA and USDA to ensure things don't fall though the cracks".........

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February 16, 2009, 9:29 PM CT

About antimicrobial resistance

About antimicrobial resistance
Antibiotic resistance and the rise of illnesses that cannot be treated easily because of drug resistance is a health concern around the world. CMAJ launches a 6-part series on antibiotic resistance to provide practical therapy guidelines for practicing doctors to manage resistant microbes in 3 settings: the hospital, clinic and home. The current issue features 3 articles on the topic.

An analysis by Dr. David Patrick from the BC Centre for Disease Control and Dr. Jim Hutchinson contains practical guidelines for clinicians to help reduce antibiotic exposure http://www.cmaj.ca/press/pg416.pdf. "Our collective prescriptions constitute an ecological problem that may reduce the success of future treatment," write Dr. Patrick and coauthor. They point out that changes to drug formularies at the institutional level and in reimbursements from provincial drug plans result in the biggest shifts in antibiotic use.

A review by Dr. Andrew Simor at Sunnybrook Health Sciences Centre in Toronto and scientists from the Public Health Agency of Canada focuses on antimicrobial resistance in hospitals, the mechanisms of antibiotic resistance, transmission of these organisms and the impact of antimicrobial resistance http://www.cmaj.ca/press/pg408.pdf. They note that enhanced monitoring, hand washing hygiene and other infection prevention control measures may help limit the increase of antibiotic resistance in Canada.........

Posted by: Mark      Read more


February 5, 2009, 6:24 AM CT

How influenza virus hijacks human cells

How influenza virus hijacks human cells
High resolution image of the key domain of the influenza virus polymerase. The active site responsible for RNA cleavage is shown in red. Its activity is crucial for the virus to multiply in human cells.

Credit: Stephen Cusack, EMBL

Influenza is and remains a disease to reckon with. Seasonal epidemics around the world kill several hundred thousand people every year. In the light of looming pandemics if bird flu strains develop the ability to infect humans easily, new drugs and vaccines are desperately sought. Scientists at the European Molecular Biology Laboratory (EMBL) and the joint Unit of Virus Host-Cell Interaction (UVHCI) of EMBL, the University Joseph Fourier (UJF) and the National Centre for Scientific Research (CNRS), in Grenoble, France, have now precisely defined an important drug target in influenza. In this week's Nature they publish a high-resolution image of a crucial protein domain that allows the virus to hijack human cells and multiply in them.

When the influenza virus infects a host cell its goal is to produce a number of copies of itself that go on to attack even more cells. A viral enzyme, called polymerase, is key to this process. It both copies the genetic material of the virus and steers the host cell machinery towards the synthesis of viral proteins. It does this by stealing a small tag, called a cap, from host cell RNA molecules and adding it onto its own. The cap is a short extra piece of RNA, which must be present at the beginning of all messenger RNAs (mRNAs) to direct the cell's protein-synthesis machinery to the starting point. The viral polymerase binds to host cell mRNA via its cap, cuts the cap off and adds it to the beginning of its own mRNA a process known as 'cap snatching'. But exactly how the polymerase achieves this and which of the three subunits of the enzyme does what, has remained controversial.........

Posted by: Mark      Read more         Source


February 4, 2009, 5:53 AM CT

How a deadly fungus evades the human immune system

How a deadly fungus evades the human immune system
This is a polysaccharide capsule of C. neoformans by Scanning Electron microscopy.

Credit: Albert Einstein College of Medicine

Scientists at Albert Einstein College of Medicine of Yeshiva University have discovered how a deadly microbe evades the human immune system and causes disease.

The study, reported in the journal Proceedings of the National Academy of Sciences (PNAS), may help researchers develop new therapies or vaccines against infections caused by Cryptococcus neoformans These fungal infections occur most usually in those with compromised immune systems ─ particularly AIDS patients and transplant patients who must take lifelong immunosuppressive treatment. The fungus causes an estimated one million deaths each year worldwide, including some 600,000 in sub-Saharan Africa. The main author of the study was Susana Frases-Carvajal, Ph.D., a postdoctoral fellow in microbiology & immunology at Einstein.

C. neoformans typically enters the body through the lungs and can spread throughout the body, including the brain. The resulting infection, called cryptococcosis, can cause chest pain, dry cough, abdominal swelling, headache, blurred vision, or confusion. The infection can be fatal, particularly if not treated with antifungal medications.

"It's a horrendous disease, and even with treatment, you often can't get rid of it," says the paper's senior author, Arturo Casadevall, M.D., Ph.D., professor and chair of microbiology & immunology.........

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January 30, 2009, 6:12 AM CT

Blue light destroys staph infection

Blue light destroys staph infection
Two common strains of methicillin-resistant Staphylococcus aureus, usually known as MRSA, were virtually eradicated in the laboratory by exposing them to a wavelength of blue light, in a process called photo-irradiation that is described in a paper published online ahead of print in Photomedicine and Laser Surgery The article will appear in the April 2009 issue (Volume 27, Number 2) of the peer-evaluated journal published by Mary Ann Liebert, Inc. The paper is available free online at www.liebertpub.com/pho.

Antibiotic-resistant bacterial infections represent an important and increasing public health threat. At present, fewer than 5% of staphylococcal strains are susceptible to penicillin, while approximately 40%-50% of Staph aureus isolated have developed resistance to newer semisynthetic antibiotics such as methicillin as well.

Chukuka S. Enwemeka, Deborah Williams, Sombiri K. Enwemeka, Steve Hollosi, and David Yens from the New York Institute of Technology (Old Westbury, NY) had previously demonstrated that photo-irradiation using 405-nm light destroys MRSA strains grown in culture. In the current study, "Blue 470-nm Light Kills Methicillin-Resistant Staphylococcus aureus (MRSA) in Vitro," the authors exposed bacterial colonies of MRSA to various doses of 470-nm light, which emits no UV radiation.........

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January 26, 2009, 11:28 PM CT

Was it the chicken salad you ate or a bad swim?

Was it the chicken salad you ate or a bad swim?
A newly released study finds swimming, having a private well or septic system, and other factors not involving food consumption were major risk factors for bacterial intestinal infections not occurring in outbreaks.

Outbreaks associated with food, such as the current Salmonella outbreak involving peanut butter that has sickened more than 500 people in 43 states, account for only about 10 percent of intestinal infections, which are medically termed as enteric infections. The newly released study, in the February 15 issue of The Journal of Infectious Diseases, now available online, suggests that methods for controlling bacterial enteric outbreaks may not be completely relevant to controlling the other 90 percent or so that occur sporadically.

In a USDA-sponsored, two-year study of children and adolescents in three Washington state counties, the investigators, led by Donna M. Denno, MD, MPH, of the University of Washington, and Phillip I. Tarr, MD, of Washington University, St. Louis, interviewed 296 patients, aged 19 years or less, who were infected at some point between 2003 and 2005 and who were matched with 580 uninfected controls. Laboratory tests identified the bacteria responsible for infection as Campylobacter in 151 cases, Salmonella in 86 cases, Escherichia coli O157 in 39 cases, and Shigella in 20 cases.........

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January 20, 2009, 6:20 AM CT

Our microbes, ourselves

Our microbes, ourselves
The team's study is the first molecular survey of gut microbial diversity following surgical weight loss (gastric bypass), and has helped solidify the link between methane producing microbes and obesity. This means the drastic anatomical changes created by gastric bypass surgery appear to have profound effects on the microorganisms that inhabit the intestine. This change may be part of the reason that gastric-bypass surgery is the most effective means to treat obesity today.

Credit: Mayo Clinic

In terms of diversity and sheer numbers, the microbes occupying the human gut easily dwarf the billions of people inhabiting the Earth. Numbering in the tens of trillions and representing a number of thousands of distinct genetic families, this microbiome, as it's called, helps the body perform a variety of regulatory and digestive functions, a number of still poorly understood.

How this microbial mlange appears to be associated with body weight changes linked to morbid obesity is a relevant and important clinical question that has received recent attention. Now, a newly released study suggests that the composition of microbes within the gut may hold a key to one cause of obesityand the prospect of future therapy.

In the January 19 early online edition of the Proceedings of the National Academy of Science, scientists at Arizona State University's Biodesign Institute in collaboration with colleagues at the Mayo Clinic, Arizona, and the University of Arizona, reveal a tantalizing link between differing microbial populations in the human gut and body weight among three distinct groups: normal weight individuals, those who have undergone gastric bypass surgery, and patients suffering the condition of morbid obesitya serious, often life-threatening condition linked to diabetes, cardiovascular disease, cancer and psychosocial disorders. Obesity affects around 4 million Americans and, each year, some 300,000 die from obesity-related illness.........

Posted by: Mark      Read more         Source


January 20, 2009, 6:17 AM CT

Resistance to antibiotic on the rise

Resistance to antibiotic on the rise
A report by scientists in the Jan. 19, 2009 Archives of Otolaryngology-Head and Neck Surgery shows that there was nationwide increase in the prevalence of pediatric methicillin-resistant Staphylococcus aureus (MRSA) head and neck infections from January 2001 to December 2006.

The increase in antibiotic-resistant infections has become a big concern for scientists and clinicians over the years. MRSA was once a condition that was only found in hospital settings; however, over the last decade MRSA outbreaks have increasingly been found in patients without risk factors.

In an attempt to identify trends in the susceptibility of antibiotic-resistant infections, scientists from Emory University School of Medicine and Children's Healthcare of Atlanta studied data on pediatric patients from nationwide hospitals.

"The growing concern about the recent worldwide MRSA epidemic has fueled the curiosity of the scientific community to gain insight into the clinical and epidemiologic manifestations of this microbe," says Steven E. Sobol, MD, MSc, primary investigator of the study and director of Pediatric Otolaryngology in the Department of Otolaryngology - Head and Neck Surgery at Emory.

"Prior studies have established that skin and soft tissue infections in some communities are due to MRSA," he says. "However, it has been observed in several institutions that there is a significant rise in pediatric head and neck infections as well".........

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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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