Archive for October 2010
Following a healthy lifestyle, which means exercising, eating healthfully, keeping the waistline trim, limiting alcohol intake, and avoiding smoking, could reduce the risk of colorectal cancer by 23%, according to a study from Denmark.
For the first time, human cells have been used to create a lab-grown liver.
It’s a milestone on the way to creating a new source of livers for transplant, Wake Forest University (WFU) researchers say.
Last June, a different research team reported growing a liver from animal cells. But if the goal is human transplants, fully human livers are likely to be safer and more effective, suggests project director Shay Soker, PhD, professor of regenerative medicine at WFU.
“We have focused on the clinical aspect of this by using human cells,” Soker tells WebMD. “We believe that the use of human cells will provide patients with the best solution for liver disease, compared with those that have used animal cells which are less safe.”
A never-before detected strain of virus that killed more than one-third of a monkey colony at a U.S. lab appears to have ‘jumped’ from the animals to sicken a human scientist, researchers report.
Although it’s an unusual move for that type of virus and does warrant further monitoring, the researchers stress there is no cause for alarm at this time. There is no evidence the virus has spread beyond the single scientist — who recovered from her illness — nor is there even proof that the virus would be transmissible between humans.
At some point in Karen Pihl’s life, one of her lung cells made a potentially fatal misstep. As the cell duplicated its DNA in preparation to divide, part of the gene for one protein became erroneously attached to part of the gene for another. The genetic malfunction bestowed the cell with the ability to grow out of control, ultimately creating lung cancer.
Today, Pihl is part of a clinical trial, being published in the New England Journal of Medicine, of an experimental lung cancer drug that specifically blocks the effects of that mutation. According to the findings, the drug, called crizotinib and developed by Pfizer, shrank tumors in half of patients whose cancers carried a similar genetic mistake. The drug suppressed tumor growth in another third.
After receiving chemotherapy, many cancer patients go into a remission that can last months or years. But in some of those cases, tumors eventually grow back, and when they do, they are frequently resistant to the drugs that initially worked.
Now, in a study of mice with lymphoma, MIT biologists have discovered that a small number of cancer cells escape chemotherapy by hiding out in the thymus, an organ where immune cells mature. Within the thymus, the cancer cells are bathed in growth factors that protect them from the drugs’ effects. Those cells are likely the source of relapsed tumors, said Michael Hemann, MIT assistant professor of biology, who led the study.
Posted October 26, 2010on:
Periodontitis, a common inflammatory disease in which gum tissue separates from teeth, leads to accumulation of bacteria and potential bone and tooth loss. Although traditional treatments concentrate on the bacterial infection, more recent strategies target the inflammatory response. In an article in the November issue of the Journal of the American Dietetic Association, researchers from Harvard Medical School and Harvard School of Public Health found that dietary intake of polyunsaturated fatty acids (PUFAs) like fish oil, known to have anti-inflammatory properties, shows promise for the effective treatment and prevention of periodontitis. Read the rest of this entry »
For decades, medications for depression have acted pretty much the same way–by manipulating levels of serotonin and other chemical messengers in the brain. New drugs have offered only modest changes from the old ones.
Now a team of researchers, led by Michael Kaplitt, an associate professor at Weill Cornell Medical College, has proposed a different way to attack depression: by using gene therapy to boost levels of a protein called p11 in an area of the brain called the nucleus accumbens.
Did biology evolve a way to protect offspring from the ravages of aging by creating a physical barrier that separates the parent from its young?
The idea that every organism must age was a concept that surprised many biologists. For a long time, aging was thought to be a process occurring only in multicellular organisms. The reason for this arguably odd presumption was that we knew somatic cells—such as those that comprise the kidney, brain, and liver—lost their functionality over time: they aged. Furthermore, those cells divided only a limited number of times, around 50, after which they reached the so-called Hayflick limit, stopped proliferating, and died.
Unicellular organisms were thought to be capable of dividing forever, as long as conditions allowed: one generation begetting the next down through time—a sort of immortality. If unicellular organisms were like somatic cells, then they would age as they divide, reach the Hayflick limit, and die.
Parents who research treatments for autism are confronted with a bewildering array of options, almost all of which have never been tested for safety and effectiveness. Organizations like The Cochrane Collaboration, which reviews the quality of evidence for medical treatments, are putting more effort into evaluating popular alternative treatments.
Hormone treatment after menopause, already known to increase the risk of breast cancer, also makes it more likely that the cancer will be advanced and deadly, a study finds.
Women who took hormones and developed breast cancer were more likely to have cancerous lymph nodes, a sign of more advanced disease, and were more likely to die from the disease than were breast cancer patients who had never taken hormones.
The increased risks were relatively small and are not fully understood. But previous research has found that hormone treatment can cause delays in diagnosis by increasing breast density, making tumors harder to see on mammograms. Delayed diagnosis may increase the risk of death.
Now scientists have identified a gene that has a “big, big effect” on how people respond to alcohol, says Kirk Wilhelmsen, senior author of a paper posted Tuesday by the journal Alcoholism: Clinical and Experimental Research. About 10% to 20% of the population carry a version of the gene that makes their brains especially sensitive to alcohol.
The finding, Wilhelmsen says, “potentially changes the paradigm about how we think about how alcohol affects the brain.” While the finding doesn’t yet have any treatment application, he says, “my expectation is this is actually going to lead somewhere.”
Posted October 25, 2010on:
By comparing a clearly defined visual input with the electrical output of the retina, researchers at the Salk Institute for Biological Studies were able to trace for the first time the neuronal circuitry that connects individual photoreceptors with retinal ganglion cells, the neurons that carry visual signals from the eye to the brain.
Their measurements, published in the Oct. 7, 2010, issue of the journal Nature, not only reveal computations in a neural circuit at the elementary resolution of individual neurons but also shed light on the neural code used by the retina to relay color information to the brain.
When mice are given drinking water laced with a special concoction of amino acids, they live longer than your average mouse, according to a new report in the October issue of Cell Metabolism, a Cell Press publication. The key ingredients in the supplemental mixture are so-called branched-chain amino acids, which account for 3 of the 20 amino acids (specifically leucine, isoleucine, and valine) that are the building blocks of proteins