October 24, 2006, 5:48 PM CT

Virtual Colonoscopy More Expensive

Wake Forest University Baptist Medical Center scientists have observed that "virtual" colonoscopy using a computer tomography (CT) scanner is considerably more expensive than the traditional procedure due to the detection of suspicious images outside of the colon.

"Virtual colonoscopy will certainly play a role in the future of colon cancer screening," said gastroenterologist Richard S. Bloomfeld, M.S., M.D., assistant professor of medicine at Wake Forest Baptist and a member of the research team. "It is important to understand the implications of findings outside the colon before we advocate wide-spread use of this technology".

Virtual colonoscopy, also known as CT-colonography (CTC), was developed at Wake Forest Baptist. It allows doctors to use Computerized axial tomography scanners to look at the colon to detect polyps (small growths in the colon that may become malignant if they are not removed) and cancers. Virtual reality software allows them to look inside the body without having to insert a long tube (conventional colonoscopy) into the colon or without having to fill the colon with liquid barium (barium enema).

Research performed at Wake Forest Baptist and elsewhere has shown that CTC is better able to see polyps than barium enemas and is nearly as accurate as conventional colonoscopy. Most patients report that CTC is more comfortable than either procedure.........

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October 22, 2006, 11:03 PM CT

Novel Studies Of Human Infection

A new type of laboratory mouse developed at UT Southwestern Medical Center can fight certain infections the same way humans do, making the rodents very useful for novel studies of human-pathogen interaction and developing disease therapies.

Normal mice are not susceptible to human-specific viruses, such as Epstein Barr virus and HIV, making it hard to study and craft drugs to target the viruses. Epstein Barr is a virus that causes mononucleosis.

So UT Southwestern researchers, working with University of Minnesota collaborators, generated human-mice "chimeras" mice implanted with human tissues and human stem cells that developed fully functional human immune systems and infection-fighting cells, such as T cells, throughout their bodies, as per a research studypublished online today in Nature Medicine

The T cells in the mice even mounted a potent immune response to toxic shock syndrome and infection by Epstein Barr.

"These human-mice 'chimeras' are susceptible to a variety of human-specific viruses that couldn't be easily studied in the past, giving researchers a new way to study, develop and implement novel vaccines and therapeutics to fight human disease like cancer and AIDS," said Dr. J. Victor Garcia, professor of internal medicine at UT Southwestern and the study's senior author.........

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October 19, 2006, 9:22 PM CT

Fusion In The Fast Lane

Using fast digital imaging, researchers from the Max Planck Institute of Colloids and Interfaces in Potsdam, Gera number of, together with scientists from Collge de France, have succeeded in developing two different protocols by which one can initiate the fusion process in a controlled manner and observe the subsequent fusion dynamics with a temporal resolution in the microsecond regime. For both protocols, the opening of the fusion necks was found to be very fast, with an average expansion velocity of centimetres per second. This velocity indicates that the initial formation of a single fusion neck can be completed in a few hundred nanoseconds. (Proceedings of the National Academy of Sciences of the USA 103, 15841-15846, October 24, 2006).

The process of membrane fusion is essential for the structure and dynamics of all cells in our bodies. Fusion is indispensable for intracellular vesicle traffic, which sustains the compartmental organisation of cells. Likewise, membrane fusion is the basic molecular process that controls the communication between cells via the secretion of hormones, neurotransmitters, and growth factors. Furthermore, fusion processes are also crucial for the interactions between our cells and various pathogens such as viruses and bacteria. However, in spite of the ubiquity of membrane fusion, a number of aspects of this process have remained rather controversial. This situation reflects the absence of well-defined protocols by which one can induce fusion in a controlled manner and subsequently study its dynamics with high temporal resolution.........

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October 17, 2006, 9:30 PM CT

Bacteria Increase Risk Of Stomach Cancer

The bacteria Helicobacter pylori substantially increase the risk of cancer in the lower stomach, but it may decrease the risk of cancer near the junction between the esophagus and the stomach, according to a study in the October 19 Journal of the National Cancer Institute. This finding may help explain the changing rates and distributions of these cancers in Western countries over the past century.

Infection with H. pylori, which is known to cause ulcers, has also been associated with certain types of gastric cancer, but the strength of association varies with where the cancer is located in the stomach. Two types of gastric cancer commonly exist -- cardia, or cancer of the upper stomach joining the esophagus; and noncardia, or cancer of the lower stomach.

A group of researchers led by Farin Kamangar, M.D., Ph.D., of the National Cancer Institute in Bethesda, Md., selected 234 cardia and noncardia gastric cancer patients in the Alpha-Tocopherol, Beta-Carotene Cancer Prevention Study and matched them to controls. They assessed all of the subjects for H. pylori infection by testing their blood for antibodies that indicate prior infection.

The authors found that the subjects infected with H. pylori had a higher risk of developing noncardia gastric cancer and a lower risk of developing cardia gastric cancer. They suggest that a decrease in H. pylori infections during the past century may be one reason that scientists have observed increasing rates of cardia and decreasing rates of noncardia gastric cancers in Western countries.........

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October 12, 2006, 5:11 AM CT

Potential New Drug For Multiple Sclerosis

Virginia Commonwealth University researchers have identified a unique mechanism of action of a new drug that shows great promise for the treatment of multiple sclerosis.

The researchers report the unique action of FTY720, or Fingolimod, an immunosuppressant drug that was already known to affect the functioning of the immune system by preventing the egress of white blood cells from the lymph nodes into the blood. The article was pre-published as a First Edition Paper in Blood, The Journal of the American Society of Hematology, which appeared online on Sept. 28.

In this study, the research team observed that FTY720 also inhibited the activity of a key enzyme called cPLA2, which is necessary for the production of inflammatory mediators, known as eicosanoids. Eicosanoids drive inflammatory disorders such as asthma and multiple sclerosis.

According to Sarah Spiegel, Ph.D., professor and chair in the VCU Department of Biochemistry, and lead author on the study, the inhibition of cPLA2 would shut down the entire inflammatory pathway, possibly without the side-effects caused by medications such as Vioxx, that have been withdrawn from the pharmaceutical market.

FTY720, a drug developed by Novartis, has shown considerable therapeutic effects in a recent small, placebo-controlled clinical trial involving patients with relapsing multiple sclerosis. The study was published in the September 2006 issue of the New England Journal (NEJM) by an international research team. With its novel mode of action and the added benefit of an oral formulation, further clinical development of FTY720 might have a major impact on treatment of MS, said Spiegel.........

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October 5, 2006, 10:20 PM CT

New Technique To Boost Protein Analysis

Imagine you had to break a secret code, but you could see only part of the message. That's the kind of frustration researchers face when trying to identify proteins and characterize how those proteins are modified in cells by biological processes.

But now, Cornell researchers have extended a powerful technique to increase by fourfold the size of a protein that can be analyzed, to those containing more than 2,000 amino acids, up from about 500.

Called a "top-down" approach, the technique uses a mass spectrometer, which measures the masses of ions or charged particles. Researchers break up the protein into pieces and weigh both the masses of the whole protein and of the individual pieces. By matching the weight of the whole protein and its pieces with those of known protein sequences in a database, they can identify the protein. Any differences in mass with known proteins can help researchers also find where and how proteins have been modified in cells.

For example, if a section of a protein has an increased weight of 16, researchers can tell that the protein has been oxidized within that section, which means that an oxygen atom (with an atomic weight of 16) was added.

"When you isolate a protein from a mixture, your first problem is to know which one it is," said Fred McLafferty, Cornell's Peter J.W. Debye Professor Emeritus of Chemistry and Chemical Biology and senior author of the paper published in the Oct. 6 issue of the journal Science. "Mass spectrometry characterizes a protein by measuring the masses produced from it".........

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October 1, 2006, 8:16 PM CT

What Drives Your Taste Buds

What are the genes that are crucial to the taste bud development?

The gene, SOX2, stimulates stem cells on the surface of the embryonic tongue and in the back of the mouth to transform into taste buds, according to the researchers. Stem cells are immature cells that can develop into several different cell types depending on what biochemical instructions they receive.

"Not only did we find that SOX2 is crucial for the development of taste buds, but we showed that the amount of SOX2 is just as important," said Brigid Hogan, Ph.D., chair of the Duke University Medical Center Department of Cell Biology and senior member of the research team. "If there isn't enough SOX2 present, or if there is too much, the stem cells will not turn into taste buds".

The researchers made their discovery in mice, but they believe the same process occurs in humans.

According to the researchers, the findings will help scientists better understand how the behavior of certain stem cells is controlled. The SOX2 gene is already known to be crucial in controlling whether embryonic stem cells remain undifferentiated and whether stem cells in the brain, eye and inner ear differentiate into specialized nerve cells.

Taste bud cells, much like skin cells, continually slough off and are replaced by new ones. So the new findings not only provide insights into the interactions between SOX2 and tongue stem cells during embryonic development, but also into how stem cells continue to operate in adults, the researchers said.........

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October 1, 2006, 8:09 PM CT

Cloned mice created from non-stem cel

Did you know that stem cells are not actually required for cloning?

New research dismisses the notion that adult stem cells are necessary for successful animal cloning, proving instead that cells that have completely evolved to a specific type not only can be used for cloning purposes, but they may be a better and more efficient starting point. As proof, researchers report they created two mouse pups from a type of blood cell that itself is incapable of dividing to produce a second generation of its own kind.

This is the first demonstration that an animal can be derived directly from a fully differentiated cell, report lead researchers Xiangzhong (Jerry) Yang, Ph.D., of the University of Connecticut, and Tao Cheng, M.D., of the University of Pittsburgh, in the journal Nature Genetics. Moreover, they say results of their studies provide compelling evidence that Dolly the sheep and other mammals cloned by somatic cell nuclear transfer were most likely derived from fully differentiated cells, not adult stem cells, as most have argued in the nine years since Dolly was first created. Because stem cells have the ability to self-renew and differentiate into any specialized cell type, they have been heralded for their promise for treating a variety of diseases and conditions. Yet, even for cloning of an embryo to the blastocyst stage, from which embryonic stem cells can be generated, adult stem cells have yielded disappointing results, with success rates in the range of 1 to 5 percent.........

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September 28, 2006, 8:31 PM CT

Virulence Of 1918 Influenza Virus

It always puzzled the scientists, why the pandemic flu in 1918 was so rampant and the virus was so virulent.

The first comprehensive analysis of an animal's immune response to the 1918 influenza virus provides new insights into the killer flu, report federally supported scientists in an article appearing online today in the journal Nature. Key among these insights, they found that the 1918 virus triggers a hyperactive immune response that may contribute to the lethality of the virus. Furthermore, their results suggest that it is the combination of all eight of the 1918 flu virus genes interacting synergistically that accounts for the exceptional virulence of this virus.

Michael G. Katze, Ph.D., of the University of Washington School of Medicine, Seattle, led the research team with University of Washington's John Kash, Ph.D. The work with the fully reconstructed 1918 virus was conducted by coauthor Terrence Tumpey, Ph.D., in a biosafety level 3-enhanced laboratory at the U.S. Centers for Disease Control and Prevention in Atlanta.

"Understanding as much as possible about the virus that caused the devastating 1918-1919 influenza pandemic is an urgent imperative as we pursue efforts to prepare for--and possibly thwart--the next flu pandemic," says NIH Director Elias A. Zerhouni, M.D.........

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September 27, 2006, 8:36 PM CT

The Mystery of Flesh-Eating Bacteria

A Howard Hughes Medical Institute (HHMI) international research scholar in Israel has discovered one reason why so-called "flesh-eating" bacteria are so hard to stop.

Emanuel Hanski, a microbiologist at Hebrew University in Jerusalem, and colleagues have found that the success of group A Streptococcus is due in part to a protein that blocks the immune system's distress calls. The findings, published in the October 4, 2006, issue of the EMBO Journal, could lead to new strategies for treating necrotizing fasciitis and halting its rapid destruction of tissue. The paper was published in advance online.

The bacterium, group A Streptococcus, wreaks destruction on muscle and skin tissue in the form of necrotizing fasciitis, which kills roughly 30 percent of its victims and leaves the rest disfigured. Antibiotics and surgical interventions, the known treatments, often fail. Necrotizing fasciitis is a serious but rare infection of the skin and the tissues beneath it.

The work began two years ago, when Hanski developed a mouse model for necrotizing fasciitis. After injecting the mice with a virulent strain of Streptococcus of a type known as M14, isolated from a necrotizing fasciitis patient, the team noticed that unlike most strep infections, in which white blood cells swarm invading bacteria to clear them from the body, few white blood cells appeared at the M14 infection site. A similar phenomenon had been observed in patients with necrotizing fasciitis but did not receive sufficient attention at the time.........

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