December 11, 2006, 4:57 AM CT
Challenging The Theory Of Memory Storage
The brain’s neocortex (blue) and the hippocampus (red)
Image: Mayank Mehta/Brown Universit
Daily events are minted into memories in the hippocampus, one of the oldest parts of the brain. For long-term storage, researchers think that memories move to the neocortex, or "new bark," the gray matter covering the hippocampus. This transfer process occurs during sleep, particularly during deep, dreamless sleep.
A number of neuroresearchers have embraced and built upon this theory of memory storage, or consolidation, for a generation. But the theory is difficult to test. New research led by Brown University neuroscientist Mayank Mehta, conducted with Nobel Prize-winning physiologist Bert Sakmann, shows the best evidence yet of the sleep dialogue between the old brain and the.
Their work, published in Nature Neuroscience, also shows that this interaction occurs in a startling way. Instead of the hippocampus uploading information to the neocortex in a burst of brain cell communication, Mehta found the opposite: the neocortex seems to drive the dialogue with the hippocampus.
The findings may give researchers a new understanding of how the brain manages memories in health and during dementia, offering up a fresh look at the causes of diseases such as Alzheimer's, as well as potential therapys.
"Long-term memory making may be a very different process than we previously thought," said Mehta, an assistant professor in the Department of Neuroscience at Brown. "Either this reversed dialogue is, somehow, a part of memory storage or this transfer of information from the old to the new brain may not occur during sleep. Either way, the results call into question usually held theories about the role of cortico-hippocampal dialogue in sleep".........
Posted by: Daniel Permalink Source
December 10, 2006, 9:13 PM CT
Reduced Body Temperature Extends Lifespan
Scientists at The Scripps Research Institute have found that reducing the core body temperature of mice extends their median lifespan by up to 20 percent. This is the first time that changes in body temperature have been shown to affect lifespan in warm-blooded animals.
The findings appear in a paper in the journal Science on November 3.
"Our study shows it is possible to increase lifespan in mice by modest but prolonged lowering of core body temperature," said Bruno Conti, an associate professor at Scripps Research who led the study. "This longer lifespan was attained independent of calorie restriction".
Prior to this study, researchers had known that core body temperature and aging were related in cold-blooded animals. Scientists had also known that lifespan could be extended in warm-blooded animals by reducing the number of calories they consumed, which also lowered core body temperature. But the degree of calorie restriction needed to extend lifespan is not easy to achieve, even in mice.
Prior to the current study, critical questions about the relation between calorie restriction, core body temperature, and lifespan remained unanswered. Was calorie restriction itself responsible for longer lifespan, with reduced body temperature simply a consequence? Or was the reduction of core body temperature a key contributor to the beneficial effects of calorie restriction? Conti and colleagues wanted to find out.........
Posted by: Janet Permalink Source
December 10, 2006, 9:17 PM CT
New Treatments To Prevalent Eye Diseases
Scientists at The Scripps Research Institute have discovered a method of repairing and normalizing blood vessels in the eye through the use of stem cells derived from bone marrow. These findings may point to a new approach for developing treatments for a certain type of eye diseases.
The research, led by Scripps Research Professor Martin Friedlander, was published online November 16 in The Journal of Clinical Investigation.
In the new study, the team injected immature white blood cells from bone marrow-myeloid progenitors-into eyes with an abnormal vasculature (network of blood vessels) in a mouse model developed to mimic certain human disorders. The researchers found that not only did the progenitor cells migrate to avascular areas of the retina, but once there they differentiated into cells called microglia that actively promoted vascular repair.
"From a purely basic science perspective, this is a novel observation," says Friedlander. "Even more importantly, the study introduces the idea that bone marrow-derived myeloid progenitors could be used to treat ischemic eye disease-an entirely new paradigm".
While there had been increasing interest in microglia among scientists in the field, this is the first time microglia have been shown to contribute to the promotion of vascular repair in any organ, including the eye. These results suggest that it might be possible to use cells derived from a patient's own bone marrow or cord blood to treat such eye diseases as diabetic retinopathy or retinopathy of prematurity (ROP).........
Posted by: Mike Permalink Source
December 9, 2006, 5:45 PM CT
Sutent, One Of The New 'Targeted' Cancer Drugs
The new "smart" drugs are a really exciting element of cancer medicine. One of the new molecularly-targeted cancer drugs is Sutent. It is a "multi-targeted kinase inhibitor." A drug that inhibits several proteins involved in triggering replication in cancer cells. Basically, inhibits various kinases, a type of enzyme that transfers phosphate groups from high-energy donor molecules to specific target molecules.
Sutent (sunitinib) is an inhibitor of multiple protein kinases, platelet-derived growth factor (PDGFR), vascular endothelial growth factor receptors (VEGFR), stem cell factor receptor (KIT), FMS-like tyrosine kinase (Flt3), colony stimulating factor (CSF-1R), and the neurotrophic factor receptor (RET). Because these proteins are involved in both tumor proliferation and angiogenesis, Sutent has both anti-tumor as well as anti-angiogenic properties. In addition, because Sutent inhibits multiple kinases, it possesses activity against multiple types of tumors.
Sutent can be used as a second-line drug for tumors that are non-responsive to Gleevec. The proto-oncogene KIT, a tyrosine kinase that is inhibited by Gleevec, is overexpressed in a majority of GISTs. Some patients have suffered relapses due to acquired point mutations in KIT, which prevents Gleevec from binding to the protein. Similar mutations have been characterized in EGFR from Iressa-resistant lung cancer patients.........
Posted by: Gregory D. Pawelski Permalink Source
December 8, 2006, 5:12 AM CT
Electronic Medical Record Triples Rate Of Osteoporosis Screenings
Use of the Electronic Health Record tripled the rate of osteoporosis screenings in women who are at risk for the disease, as per a research studyconducted recently by a team of Geisinger Health System researchers.
About half of those who were screened were considered high-risk for the disease, the study found.
An estimated 10 million Americans suffer from the disease and the nation collectively spends about $18 billion per year on bone fractures correlation to osteoporosis.
EHR-screening programs can help improve those numbers, make patients' everyday lives less painful and save doctors time and resources, said Dr. Eric Newman, Geisinger's Director of Rheumatology.
The EHR was used to identify women who had not had bone density screens for osteoporosis in the last two years. Those women were sent letters and received telephone calls if their records were flagged.
"This is pretty significant," said Dr. William Ayoub of Geisinger Medical Group-Scenery Park, State College, one of the study's authors. "The EHR is streamlining the screening process and letting people know about a potential health concern before it becomes a major problem."
The EHR screening program was started in two Geisinger family practice clinics near State College, Pa. It was so successful that there are now plans to implement the program at other sites throughout the Geisinger system, Newman said.........
Posted by: Janet Permalink Source
December 8, 2006, 5:07 AM CT
Viagra Against Cancer?
Sildenafil and other "impotence drugs" that boost the production of a gassy chemical messenger to dilate blood vessels and produce an erection now also show promise in unmasking cancer cells so that the immune system can recognize and attack them, say researchers at the Johns Hopkins Kimmel Cancer Center.
Tests at Hopkins on mice with implanted colon and breast tumors showed that tumor size decreased two- and threefold in sildenafil-treated animals, in comparison to mice that did not get the drug. In mice engineered to lack an immune system, tumors were unaffected, proof of principle, the researchers say, that the drug is abetting the immune system's own cellular response to cancer.
In a report reported in the Nov. 27 issue of the Journal of Experimental Medicine, the Hopkins team says boosted levels of the chemical messenger nitric oxide appear to dampen the effects of a specialized cell that diverts the immune system away from tumors, allowing swarms of cancer-attacking T-cells to migrate to tumor sites in the rodents.
Lab-grown cancer cells treated with sildenafil showed similar results, as did tissue samples taken from 14 head and neck cancer and multiple myeloma patients.
Sildenafil, marketed under the trade name Viagra, is one of a class of drugs used to treat erectile dysfunction in millions of men, and in recent years, its ability to stimulate the production of NO has been investigated by experts in diseases associated with the activity of blood vessels and blood components.........
Posted by: Janet Permalink Source
December 8, 2006, 4:39 AM CT
Data From Robotic Medical Tools Could Improve Surgery Skills
Da Vinci Robotic System (Credit: Will Kirk/JHU)
When a surgeon operates the controls of a da Vinci robotic system, the device records these hand movements
Borrowing ideas from speech recognition research, Johns Hopkins computer researchers are building mathematical models to represent the safest and most effective ways to perform surgery, including tasks such as suturing, dissecting and joining tissue.
The team's long-term goal is to develop an objective way of evaluating a surgeon's work and to help doctors improve their operating room skills. Ultimately, the research also could enable robotic surgical tools to perform with greater precision.
The project, supported by a three-year National Science Foundation grant, has yielded promising early results in modeling suturing work. The scientists performed the suturing with the help of a robotic surgical device, which recorded the movements and made them available for computer analysis.
"Surgery is a skilled activity, and it has a structure that can be taught and acquired," said Gregory D. Hager, a professor of computer science in the university's Whiting School of Engineering and principal investigator on the project. "We can think of that structure as 'the language of surgery.' To develop mathematical models for this language, we're borrowing techniques from speech recognition technology and applying them to motion recognition and skills assessment".
Complicated surgical tasks, Hager said, unfold in a series of steps that resemble the way that words, sentences and paragraphs are used to convey language. "In speech recognition research, we break these down to their most basic sounds, called phonemes," he said. "Following that example, our team wants to break surgical procedures down to simple gestures that can be represented mathematically by computer software".........
Posted by: Scott Permalink Source
December 7, 2006, 10:05 PM CT
Hormonal Contraception Does Not Increase HIV Risk
Using hormonal contraception does not appear to increase women's overall risk of infection with the AIDS virus, report the authors of a large study commissioned by the National Institute of Child Health and Human Development of the National Institutes of Health.
The study, published on the Web site of the journal AIDS, is the largest, most comprehensive of its kind to date. It followed thousands of women in Africa and compared their patterns of contraceptive use to their risk of infection with HIV.
The NIH project officer for the study, H. Trent MacKay, M.D., M.P.H, Chief of the Contraception and Reproductive Health Branch, said the study findings do not provide a basis for changing current recommendations regarding contraceptive use.
Dr. MacKay cautioned that, eventhough hormonal contraception provides an effective means of pregnancy prevention, it does not protect against HIV or other sexually transmitted infections. Abstinence is the only sure way to prevent sexual transmission of HIV, he said. Barring abstinence, use of a latex condom, consistently and correctly, is highly effective against HIV infection.
More than 100 million women around the world use hormonal contraception, the study authors wrote. In all, 18 million women have been infected with HIV, most during heterosexual relations. "Understanding whether hormonal contraceptive use alters the risk of HIV acquisition among women is a critical public health issue," the study authors wrote.........
Posted by: Mark Permalink Source
December 7, 2006, 9:57 PM CT
New Approach To Melanoma Treatment
While investigating a fungus known to cause an infection in people with AIDS, two grantees of the National Institute of Allergy and Infectious Diseases (NIAID), part of the National Institutes of Health (NIH), unexpectedly discovered a potential strategy for treating metastatic melanoma, one of the deadliest forms of skin cancer. The therapy approach, which involves combining an antibody with radiation, has since been further developed and is expected to enter early-stage human clinical studies in 2007.
"This is an excellent example of how scientific research in one discipline may have payoffs in a completely unpredictable way," says NIAID Director Anthony S. Fauci, M.D. "This important AIDS-related research has led to the development of a promising therapeutic strategy for a terrible cancer that affects thousands of people each year."
Arturo Casadevall, M.D., Ph.D., of the Albert Einstein College of Medicine at Yeshiva University, in New York City, and his research team began studying the biology of the skin pigment melanin to better understand why its synthesis plays a role in the process whereby certain yeast-like fungi, specifically Cryptococcus neoformans, cause disease in some people. C. neoformans can cause cryptococcosis, a potentially fatal fungal infection that can lead to inflammation of the brain and death in people with AIDS and other immunocompromised individuals.........
Posted by: George Permalink Source
December 7, 2006, 9:49 PM CT
Blood Pressure Drugs Could Halt Pancreatic Cancer Spread
Common blood pressure medications might help block the spread of pancreas cancer, scientists at the Kimmel Cancer Center at Thomas Jefferson University in Philadelphia have found. The researchers showed in laboratory studies that two types of pressure-lowering drugs - ACE inhibitors and AT1R blockers - may help reduce the development of tumor-feeding blood vessels, a process called angiogenesis. Such drugs, they say, may become part of a novel strategy to control the growth and spread of cancer.
As per Hwyda Arafat, M.D., Ph.D., assistant professor of surgery at Jefferson Medical College, prior studies have linked a lower cancer incidence with the inhibition of the pancreas hormone angiotensin II (Ang II) by either ACE (Angiotensin I converting enzyme) inhibitors or AT1R (Ang II type 1 receptor) blockers. Ang II increases the production of VEGF, a vascular factor that promotes blood vessel growth in many cancers. High VEGF levels have been correlated with poor cancer prognosis and early recurrence. ACE is the enzyme that converts Ang I to Ang II.
Dr. Arafat and her co-workers examined the protein of both invasive pancreas cancer and normal pancreatic tissue, analyzing the expression of ACE and AT1R in relation to VEGF. They also looked at the effects of blood pressure drugs captopril, an ACE inhibitor, and losartan, an AT1R blocker, on VEGF production in cancer cell lines.........
Posted by: Sue Permalink Source