October 10, 2007, 4:47 AM CT
New radioactive agents for colon cancer work inside cells
Johns Hopkins researchers have developed a potentially novel way to fight colorectal cancer using tiny molecules to deliver potent barrages of radiation inside cancer cells, unlike current therapys that bind to the surface of cells and attack from the outside and cause unwanted side effects.
In laboratory studies with normal and cancer cells, the new radiation delivery system proved able to specifically target colon cancer cells, and whats left over is likely to be easily filtered out by the kidneys because the delivery systems molecules are so small.
As reported online in PLoS One on October 3, Hopkins colorectal cancer specialists John Abraham, Ph.D., and Stephen Meltzer, M.D. -working with the notion that small molecules generally make better therapy packages-designed small bits of protein only 10 amino acids long as the foundation for their drugs. By contrast, antibodies used to deliver radiation or chemicals can be over one thousand amino acids long.
The team attached radioactive phosphorous, P32, as a test of how well their peptides worked and to our surprise, our first tests showed that cells were ingesting these molecules, thus transferring the radiation inside and killing them by breaking up their DNA and proteins, Abraham says.
While cautioning that the new radiation delivery system is still far from ready for use in people, Abraham notes that P32 gives off high energy that can penetrate through 5 millimeters of human tissue, making it a good candidate to tackle colon cancer since colon cancer cells can often form large, thick tumors into which drugs may not penetrate very well. In addition, P32-labeled peptides may serve another valuable use: to find small metastases or recurrences of colon tumors while they are still small enough to treat. Images of the body can be taken of the labeled peptides as they bind, revealing where stray tumor cells may be nesting.........
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October 8, 2007, 11:21 AM CT
Apatone for cancer treatment
In a significant advancement in the ongoing battle against cancer, a group of scientists from Summa Health System, IC-MedTech and other institutions have completed the first ever FDA-approved human clinical trial of Apatone. Demonstrating promising results, Apatone exploits a new strategy to selectively lower the level of compounds within tumor cells that assist in energy production and protect against chemotherapy. This non-toxic approach weakens and kills cancers in a novel way.
Apatone was discovered by Dr. Henryk Taper from the Catholic University of Leuven in Brussels, Belgium and was developed by Dr. James Jamison and Dr. Jack Summers, both of Summa Health System, and Dr. Jacques Gilloteaux, now with the American University of the Caribbean in St. Maarten. Their groundbreaking discovery observed that moderate doses of Apatone eliminate a number of types of cancer cells, including prostate, bladder, renal and ovarian.
This strategy targets cancer cells by their inflammatory response, explains Dr. Jamison. Its a different approach than most other anti-tumor drugs, which target dividing cells or the development of blood vessels within the tumor. Since normal cells use sugars or fats for energy and cancer cells rely on glucose, the real key here is that Apatone resembles glucose. As Apatone preferentially accumulates in cancer cells, it also supplies quinone that weakens and can destroy the cancer cell from within.........
Posted by: Janet Read more Source
October 8, 2007, 9:39 AM CT
Brain Center Responsible for Tinnitus
For the more than 50 million Americans who experience the phantom sounds of tinnitus -- ringing in the ears that can range from annoying to debilitating -- certain well-trained rats may be their best hope for finding relief.
Scientists at the University at Buffalo have studied the condition for more than 10 years and have developed these animal models, which can "tell" the scientists if they are experiencing tinnitus.
These researchers now have received a $2.9 million five-year grant from the National Institutes of Health to study the brain signals responsible for creating the phantom sounds, using the animal models, and to test potential therapies to quiet the noise.
The research will take place at the Center for Hearing and Deafness, part of the Department of Communicative Disorders and Sciences in the university's College of Arts and Sciences. Richard Salvi, Ph.D., director of the center, is principal investigator. Researchers from UB's Department of Nuclear Medicine and from Roswell Park Cancer Institute in Buffalo are major collaborators on portions of the project.
Tinnitus is caused by continued exposure to loud noise, by normal aging and, to a much lesser extent, as a side effect of taking certain anti-cancer drugs. It is a major concern in the military: 30 percent of Iraq and Afghanistan combat veterans suffer from the condition.........
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October 8, 2007, 9:36 AM CT
Nanoparticle drug delivery system
Eva Harth in her laboratory.
There are two aspects to creating an effective drug: finding a chemical compound that has the desired biological effect and minimal side-effects and then delivering it to the right place in the body for it to do its job.
With the support from a $478,000, five-year CAREER award from the National Science Foundation, Eva Harth is tackling the second part of this problem. She is creating a modular, multi-functional drug delivery system that promises simultaneously to enhance the effectiveness and reduce undesirable side-effects of a number of different drugs.
(NSFs Faculty Early Career Development awards are the agencys most prestigious honor for junior faculty members and are given to individuals judged most likely to become the academic leaders of the 21st century.).
Harth, who is an assistant professor of chemistry at Vanderbilt University, has created a nanosponge specially designed to carry large numbers of drug molecules. She has also discovered a molecular transporter that, when attached to the nanosponge, carries it and its cargo across biological barriers into specific intracellular compartments, which are very difficult places for most drugs to reach. She has shown that her system can reach another difficult target: the brain. Experiments have shown that it can pass through the brain-blood barrier. In addition, she has: successfully attached a special targeting unit that delivers drugs to the surface of tumors in the lungs, brain and spinal cord and even developed a light kit for her delivery system fluorescent tags that researchers can use to monitor where it goes.........
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October 8, 2007, 8:32 AM CT
Limiting refined carbohydrates may stall AMD progression
Eating fewer refined carbohydrates may slow the progression of age-related macular degeneration (AMD), as per a new study from scientists at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University.
AMD results in partial or total blindness in 7 to 15% of the elderly, as per the Eye Diseases Prevalence Research Group. Dietary changes may be the most practical and cost-effective prevention method to combat progression of AMD, says Allen Taylor, PhD, director of the Laboratory for Nutrition and Vision Research at the USDA HNRCA. It is surprising there is so little attention focused on the relationship between AMD and carbohydrates.
The current study, reported in the recent issue of the American Journal of Clinical Nutrition, builds on a recent analysis by Taylor and his colleagues that found men and women older than 55 who consumed diets with higher-than-average dietary glycemic index foods appeared to have an increased risk for both early and later stages of AMD.
Dietary glycemic index is a scale used to determine how quickly carbohydrates are broken down into blood sugar, or glucose. Foods with a high glycemic index are linked to a faster rise and subsequent drop in blood sugar. Refined carbohydrates like white bread and white rice have high glycemic indices. Whole wheat versions of rice, pasta and bread are examples of foods with low glycemic indices.........
Posted by: Mike Read more Source
October 4, 2007, 9:35 PM CT
Cholesterol metabolism and Alzheimer's disease
Eventhough the causes of Alzheimer's disease are not completely understood, amyloid-beta (A-beta) is widely considered a likely culprit the "sticky" protein clumps into plaques thought to harm brain cells.
But now scientists at Washington University School of Medicine in St. Louis have uncovered evidence strengthening the case for another potential cause of Alzheimer's. The finding also represents the first time researchers have found a correlation between early- and late-onset Alzheimer's.
As per a research findings reported in the Oct. 4, 2007 issue of the journal Neuron, the researchers report that when A-beta is made, a small bit of protein is also released that can regulate cholesterol levels in the brain. The discovery adds weight to the less prominent theory that abnormal brain cholesterol metabolism plays a role in the mental decline seen in Alzheimer's patients.
"Our research links two major determinants for early- and late-onset Alzheimer's disease," says senior author Guojun Bu, Ph.D., professor of pediatrics and of cell biology and physiology. "And we've shown that the process that links them is implicated in brain cholesterol metabolism."
The report follows closely on another study reporting that statins, widely prescribed cholesterol-lowering drugs, could prevent certain neural changes that signal the progression of Alzheimer's disease. Additional earlier studies support the idea that statins could benefit Alzheimer's patients; however, other studies have observed no such protective effect from statins.........
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October 4, 2007, 5:14 AM CT
Towards Early Cancer Detection
A test to detect the very early stages of cancer could one day result from new research by Cardiff University scientists.
A team at the University's School of Medicine has just published a study on telomeres - small structures at the end of human chromosomes which can play a crucial part in the onset of cancer.
Telomeres control cell division in the body - by gradually becoming shorter they can tell cells when it is time to stop dividing. However when telomeres stop working properly, they can cause the cells to mutate and start dividing uncontrollably, which can lead to the formation of tumours.
The Cardiff study used ground-breaking techniques to study telomeres in human cells. The scientists found the critical length at which telomeres stop working and also that some telomeres can be shortened or deleted at random, without any external cause.
The scientists also discovered how chromosomes can fuse together once they lose the protection of their telomeres. Chromosomal fusion causes the chromosomes to disintegrate, which can result in the development of malignant growths. The Cardiff study means there is now a system which can detect chromosomal fusions from single DNA molecules, opening up the possibility of an "early-warning" test for cancer.........
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October 4, 2007, 5:07 AM CT
Converting brain signals into action
MIT scientists have developed a new algorithm to help create prosthetic devices that convert brain signals into action in patients who have been paralyzed or had limbs amputated.
The technique, described in a paper published as the cover article in the October edition of the Journal of Neurophysiology, unifies seemingly disparate approaches taken by experimental groups that prototype these neural prosthetic devices in animals or humans.
"The work represents an important advance in our understanding of how to construct algorithms in neural prosthetic devices for people who cannot move to act or speak," said Lakshminarayan "Ram" Srinivasan (S.M., Ph.D. 2006), lead author of the paper.
Srinivasan, currently a postdoctoral researcher at the Center for Nervous System Repair at Massachusetts General Hospital and a medical student in the Harvard-MIT Division of Health Sciences and Technology (HST), began working on the algorithm while a graduate student in MIT's Department of Electrical Engineering and Computer Science (EECS).
Trauma and disease can lead to paralysis or amputation, reducing the ability to move or talk despite the capacity to think and form intentions. In spinal cord injuries, strokes, and diseases such as amyotrophic lateral sclerosis (Lou Gehrig's disease), the neurons that carry commands from the brain to muscle can be injured. In amputation, both nerves and muscle are lost.........
Posted by: Daniel Read more Source
October 4, 2007, 4:50 AM CT
Stomach stem cell discovery could bring cancer insights
Researchers have identified and described stem cells specific to several tissues and organs of the body key master cells that give rise to the specialized cell types characteristic of that organ. But to date, it hasnt been possible to pinpoint functioning stem cells in the stomach, either in laboratory animals or people.
Now, a group of University of Michigan Medical School scientists has succeeded in finding and manipulating a population of cells that strongly resemble stem cells in the stomachs of mice. They have been able to show that these cells, which they call gastric progenitor cells, can give rise to all the different types (or lineages) of specialized cells needed to form the functional stomach glands that line the lower portion of the stomach. This property of multi-lineage potential is considered a key stem cell property.
The identification of these progenitor cells will not only aid in our understanding of normal cell turnover in the stomach, but could potentially open some new and exciting doors in our investigation of the origins of gastric cancer, says Deborah Gumucio, Ph.D., a U-M developmental biologist and senior author of a study which appears online ahead of print in the journal Gastroenterology.
The epithelial cells that make up the millions of glands of the stomach are constantly turning over. Most of the mature functioning cells live only 20 to 60 days before being replaced by progeny of dividing resident stem cells. These stem cells are not only a constant source of new cells, but they represent an important reservoir for repair of damage to the stomach caused by injury or inflammation. In addition, since the stem cells are the longest-lived of the gastric cells, it is thought that these are the only cells that live long enough to accumulate the multiple mutations that can cause cancers. For these reasons, the ability to identify and manipulate stomach progenitor cells has been an important goal for decades.........
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October 2, 2007, 10:34 PM CT
First significant genetic finding in severe PMS
The first significant genetic finding in premenstrual dysphoric disorder (PMDD) has now been reported. PMDD is a very severe form of the more usually known premenstrual syndrome, or PMS. PMDD is heritable, affects 5-8% of women, and is linked to severe emotional and physical problems, such as irritability, marked depressed mood, anger, headaches, weight gain and more, to such an extent that quality of life is seriously impacted. Previously, scientists have shown that women with PMDD have an abnormal response to normal hormone levels and, thus, are differentially sensitive to their own hormone changes. Huo and his colleagues now report their new findings, which link PMDD with common variants in the estrogen receptor alpha gene, in an article scheduled for publication in the October 15th issue of Biological Psychiatry.
Huo and his colleagues performed genetic testing and analyses on women diagnosed with PMDD and healthy control subjects to investigate possible sources of the genetic susceptibility to experience PMDD, and found variants in the estrogen receptor alpha gene that are linked to PMDD. In other words, women with these particular genetic variants were more likely to suffer from PMDD. Importantly, the authors also discovered that this association is seen only in women with a variant form of another gene, catechol o methyltransferase (COMT), which is involved in regulating the function of the prefrontal cortex, a critical regulator of mood. David Rubinow, M.D., lead author on this project, notes that these findings may help fill in the picture of how changes in ovarian hormones can lead to depression and why they do so only in a small subset of women.........
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