December 6, 2008, 3:51 PM CT

Exploring gene therapy to fight AIDS

The apparent success of a case in which German doctors cured a man of AIDS using a bone marrow transplant comes as no surprise to Gerhard Bauer, a UC Davis stem cell researcher. Bauer has been working for more than 10 years on a similar cure for AIDS based on replacing the devastated immune system of an HIV-infected patient with stem cells that have been engineered to resist human immunodeficiency syndrome.

Bauer plans to present the preliminary results of his latest research at the 50th annual meeting of the American Society for Hematology in San Francisco on Sunday, December 6, 2008, from 6 to 8 p.m. at the Moscone Center. He and his UC Davis research team will present a poster detailing the development of a mouse model that allows pre-clinical testing of their new gene-therapy protocol, which they hope will pave the way for human clinical trials within five years.

"The case in Gera number of was a natural gene-therapy experiment," explained Bauer, an assistant professor of hematology and oncology and director of a good manufacturing practice (GMP) laboratory now under construction in the new UC Davis Institute for Regenerative Cures in Sacramento. "We are working on a similar approach to genetically engineer a patient's own stem cells in a way that mimics this natural immunity. The German case offers further proof that genetic engineering provides a pathway to success, and gene treatment offers real hope as a cure for AIDS"......... Posted by: Emily      Read more         Source

December 4, 2008, 7:41 PM CT

Solving piece of large-scale gene silencing mystery

A team led by Craig Pikaard, Ph.D., Washington University in St. Louis professor of biology in Arts & Sciences, has made a breakthrough in understanding the phenomenon of nucleolar dominance, the silencing of an entire parental set of ribosomal RNA genes in a hybrid plant or animal.

Since the machinery involved in nucleolar dominance is some of the same machinery that can go haywire in diseases such as cancer, Pikaard and his collaborators' research may have important implications for applied medical research.

Nucleolar dominance occurs when nucleoli, protein-rich, dense regions of RNA within the nucleus, form on the chromosomes inherited from one parent, but not on the chromosomes inherited from the other parent. Expression of ribosomal RNA genes drives the formation of these nucleoli. The hybrid, a result of a cross-breeding of two different species, always "chooses" to express the ribosomal RNA genes of one particular parental species, regardless of whether that species happens to be the maternal or paternal parent.

Ribosomal RNAs, or rRNAs, are a major component of the ribosomes, the protein manufacturers of the cell. Because rRNA genes are highly redundant, cells use nucleolar dominance to control the dosage of ribosomes in an organism.

As per Pikaard, if scientists could harness the silencing machinery involved in nucleolar dominance to limit the expression of rRNA genes, they could potentially slow the growth rate of tumor cells and thereby slow the progression of diseases like cancer......... Posted by: Emily      Read more         Source

December 1, 2008, 6:09 PM CT

Routine HIV screening for all patients

Philadelphia, December 1, 2008 -- On World AIDS Day, the American College of Physicians (ACP) is giving doctors a call-to-action to routinely encourage HIV screening to all of their patients older than 13 years. This new practice guideline appears on the Annals of Internal Medicine Web site at www.annals.org.

HIV affects more than one million people in the United States. Every year, about 20,000 new infections are caused by individuals who are unaware that they are infected with HIV. Timely identification of undiagnosed cases of HIV can help prevent further transmission.

"The purpose of the guideline is to present the available evidence to physicians as a way to help guide their decisions around screening for HIV in their practice," said Amir Qaseem, MD, PhD, MHA, senior medical associate in ACP's Clinical Programs and Quality of Care Department and the lead author of the guideline. "ACP recommends that physicians adopt a routine screening policy for HIV and encourage their patients to get tested, regardless of their risk factors".

As per the guideline, physicians should offer screening to all patients, and should determine the need for repeat screening intervals on a case-by-case basis. Higher risk patients should be retested more frequently than patients who are at average risk......... Posted by: Emily      Read more         Source

December 1, 2008, 6:04 PM CT

MRI machines may damage cochlear implants

Alexandria, VA Patients with cochlear implants may want to steer clear of certain magnetic imaging devices, such as 3T MRI machines, because the machines can demagnetize the patient's implant, as per new research reported in the December 2008 issue of Otolaryngology Head and Neck Surgery

A cochlear implant is an electronic device that restores partial hearing to the deaf. It is surgically implanted in the inner ear and activated by a device worn outside the ear. Unlike a hearing aid, it does not make sound louder or clearer. Instead, the device bypasses damaged parts of the auditory system and directly stimulates the nerve of hearing, allowing individuals who are profoundly hearing impaired to receive sound. It is estimated that more than 100,000 people have cochlear implants.

The study, conducted by a team of German and American researchers, tested several cochlear device magnets on a 3T MRI scanner with active shielding at a variety of angles (0, 80, 90, 100, 110, and 180). The scientists discovered that during routine use of 3T MRI machines at angles above 80, an unacceptable level of demagnetization was reached, causing permanent damage to devices with non-removable magnets, and creating the potential of exposing patients to undesirable magnetic forces......... Posted by: Emily      Read more         Source

December 1, 2008, 6:03 PM CT

How mosquitoes avoid succumbing to viruses they transmit

Mosquitoes are like Typhoid Mary. They can spread viruses which cause West Nile fever, dengue fever, or yellow fever without themselves getting sick. Researchers long thought that the mosquito didn't care whether it had a virus hitchhiker, but have now discovered, "There is a war going on," said Zach Adelman, assistant professor of entomology at Virginia Tech.

The war is at the cellular level, between the host and invading RNA the strands of code that produce different kinds of viral proteins.

The mediators that balance the interactions between mosquito and virus are virus-derived short-interfering RNAs (viRNAs), which are generated by the mosquito's immune response to infection. "If the mosquito is not able to cut up the virus genome into viRNAs, an otherwise invisible infection becomes fatal-- for both the mosquito and the virus. In other words, to complete the circle and be transmitted back to a vertebrate host, the virus must submit, to some extent, to the mosquito's antiviral response," said Kevin M. Myles, assistant professor of entomology at Virginia Tech.

Myles, Adelman, and their Ph.D. students, who are with the Vector-borne Disease Research Group at Virginia Tech, report their findings about the war between the mosquito immune system and viruses in the Proceedings of the National Academy of Sciences (PNAS), scheduled to appear in the Online Early Edition the week of December 1-5, 2008. The article is, "Alphavirus derived small RNAs modulate pathogenesis in disease vector mosquitoes," by Myles; Michael R. Wiley of Ambler, Pa.; Elaine M. Morazzani of Vienna, Va.; and Adelman......... Posted by: Emily      Read more         Source

November 25, 2008, 9:53 PM CT

Fragile X testing throughout the lifespan

Writing in this week's Journal of the American Medical Association, UC Davis M.I.N.D. Institute scientists urge physicians to test for mutations of the fragile X gene in patients of all ages. That's because, after decades of research, it is clear that mutations in this gene cause a range of diseases, including neurodevelopmental delays and autism in children, infertility in women and neurodegenerative disease in elderly adults.

"We want to notify specialists in a variety of areas, as well as allied health professionals, of the potential impact of the fragile X mutation at different times in patients' lives," said Randi Hagerman, director of the Fragile X Research and Treatment Center at the UC Davis M.I.N.D. Institute.

Hagerman, who is also the institute's medical director, co-authored the commentary with fellow M.I.N.D. Institute researcher and husband, Paul Hagerman, who is also director of the UC Davis NeuroTherapeutics Research Institute (NTRI).

Without testing for fragile X mutations, the Hagermans write, patients can be misdiagnosed.

"These patients don't have the advantage of targeted therapys and specific therapies," Randi Hagerman said.

The families of these patients are also at risk because the mutations are passed on from generation to generation......... Posted by: Emily      Read more         Source

November 24, 2008, 9:47 PM CT

COPI complex is a regulator of lipid homeostasis

Magazine articles describing ways to burn fat, lose weight, etc. are omnipresent in Western culture, but science's understanding of the way fat is stored in the cells of the human body is rather slimmer. In this week's issue of PLoS Biology, a new paper by Dr. Mathias Beller, Carole Sztalryd, and his colleagues investigates some of the mysteries surrounding how our bodies store and release fat. Understanding lipid storage and use is important in tackling obesity and other metabolic disorders, and the authors identify a cellular pathway that regulates lipid storage, and show that interrupting it can reduce the amount of fat sequestered by our cells.

Fat is a major source of energy, and humans must consume a certain amount daily to remain healthy. Excess fat is stored in the cells of the body by converting the fatty acids found in food into droplets. These droplets then sit within a cell until the energy contained is required. The processes that create droplets and break them down again have previously been poorly understood. New work, led by Dr. Brian Oliver, of the National Institute of Diabetes and Digestive and Kidney Diseases in the USA, has identified some of the proteins that regulate the process, using first fruitflies and then mice, and have also identified chemicals that can perturb the pathway......... Posted by: Emily      Read more         Source

November 24, 2008, 9:37 PM CT

Sperm size isn't everything

Contrary to common scientific belief, the length of a sperm's tail does not always determine how fast it can swim. Research reported in the open access journal BMC Evolutionary Biology has shown that in the counter-intuitive microscopic world in which sperm operate, streamlining and longer tails don't always provide a speed advantage.

Stuart Humphries, from the University of Sheffield, and collaborators from the University of Western Australia have critically reviewed the evidence linking sperm shape to swimming speed. He said, "It seems clear that some assumptions regarding the physics of sperm locomotion have hampered our progress in understanding the processes mediating sperm competition. It is usually believed that selection for increased sperm performance will favor the evolution of longer, and therefore faster swimming, sperm. In fact, the relative lengths of a sperm's constituent parts, rather than their absolute lengths, are likely to be the target of selection."

Small size and low swimming speeds mean that, in hydrodynamic terms, sperm operate in a very different regime from the one that we are used to. At this microscopic scale, eventhough a longer tail does allow a sperm to generate more thrust, the drag created by a sperm's head is often enough to counteract any such gains. As per Humphries, "We suggest that, irrespective of whether tail length, total length or head length is used, any attempts to correlate a single measure of length to speed are likely to be futile. We argue that accounting for the balance between drag from the head and thrust from the tail will allow us to extend our understanding of the link between sperm form and function"......... Posted by: Emily      Read more         Source

November 24, 2008, 9:36 PM CT

Stomach ulcer bug causes bad breath

Bacteria that cause stomach ulcers and cancer could also be giving us bad breath, as per research reported in the recent issue of the Journal of Medical Microbiology For the first time, researchers have found Helicobacter pylori living in the mouths of people who are not showing signs of stomach disease.

The mouth is home to over 600 different species of bacteria, some of which can cause disease. Helicobacter pylori has recently been shown to cause stomach ulcers and is also responsible for a large proportion of gastric cancers. Researchers estimate that between 20 and 80 % of people in the developed world and over 90 % of people in the developing world carry the bacterium.

"Recently, researchers discovered that H. pylori can live in the mouth," said Dr Nao Suzuki from Fukuoka Dental College in Fukuoka, Japan. "We wanted to determine whether the bacteria can cause bad breath, so we tested patients complaining of halitosis for the presence of H. pylori".

The scientists found the bacteria in the mouths of 21 out of 326 Japanese people with halitosis (6.4%). In these people, the concentration of a bad breath gas and the level of oral disease was significantly higher. In patients with periodontal (gum) disease, 16 of 102 people (15.7%) had H. pylori in their mouths......... Posted by: Emily      Read more         Source

November 21, 2008, 8:42 PM CT

Heart patients are often not treated in accordance with guidelines

A number of patients with cardiovascular disease are not given adequate drug treatment. This is the result of an international study. In the current edition of Deutsches rzteblatt International (Dtsch Arztebl Int 2008; 105[45]: 769-75), Uwe Zeimer et al. present the German results of this prospective, one-year survey.

512 doctors in Gera number of participated in the study. They enrolled 5594 patients in all, of whom 89.2% suffered from one or more cardiovascular diseases and 10.8% only exhibited risk factors. Documented risk factors included high blood pressure, disturbances in lipid metabolism, diabetes, and obesity. The results showed that several vascular beds were affected simultaneously in almost one third of patients. A number of patients also suffered from other diseases requiring therapy, which were defined as risk factors. After one year, 2.1% of the patients with cardiovascular disease and 1.5% of the patients with at least three risk factors had died.

The study demonstrated that only three quarters of patients were given drugs to reduce fat levels. The same proportion was given drugs to dilute blood. Moreover, the doctors failed to exhaust the possibilities for drug therapy. This may be the reason that 27% of the patients with hypertension failed to reach the target blood pressure and 66% of the patients with disturbances in lipid metabolism failed to reach the target cholesterol level......... Posted by: Emily      Read more         Source