December 21, 2010, 6:23 AM CT
Malaria-infected cells stiffen, block blood flow
The malaria parasite inside a red blood cell, left, and in a computer-generated model. Malarial infection inhibits the smooth flow of blood through capillaries.
Credit: George Karniadakis, Brown University
Eventhough the occurence rate of malaria has declined in all but a few countries worldwide, as per a World Health Organization report earlier this month, malaria remains a global threat. Nearly 800,000 people succumbed to the mosquito-borne disease in 2009, nearly all of them in the developing world.
Physicians do not have reliable therapy for the virus at various stages, largely because no one has been able to document the malaria parasite's journeys in the body.
Now scientists at Brown University and the Massachusetts Institute of Technology have used advanced computer modeling and laboratory experiments to show how malaria parasites change red blood cells and how the infected cells impede blood flow to the brain and other critical organs.
Their findings, reported in the early online edition of the Proceedings of the National Academy of Sciences,
could help doctors chart, in real time, the buildup in the body of cells infected with malaria or other diseases (such as sickle-cell anemia) and to prescribe therapy accordingly.
"The idea is to predict the evolution of these diseases, just like we predict the weather," said George Karniadakis, professor of applied mathematics at Brown and corresponding author on the paper.
The scientists worked with Plasmodium falciparum, a parasite that can cause cerebral malaria by lodging in capillaries of the brain, particularly among children. The parasite is found globally but is most common in Africa.........
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December 21, 2010, 6:21 AM CT
Chemotherapy boost survival of older teenage leukemia patients
More effective risk-adjusted chemotherapy and sophisticated patient monitoring helped push cure rates to nearly 88 percent for older adolescents enrolled in a St. Jude Children's Research Hospital acute lymphoblastic leukemia (ALL) therapy protocol and closed the survival gap between older and younger patients battling the most common childhood cancer.
A report online in the December 20 edition of the Journal of Clinical Oncology noted that overall survival jumped 30 percent in the most recent therapy era for ALL patients who were age 15 through 18 when their cancer was found.
The study compared long-term survival of patients treated between 2000 and 2007 in a protocol designed by St. Jude researchers with those enrolled in earlier St. Jude protocols. About 59 percent of older patients treated between 1991 and 1999 were cured, compared with more than 88 percent of children ages 1 through 14 treated during the same period. But overall survival for older patients rose to almost 88 percent between 2000 and 2007, when long-term survival of younger patients soared to about 94 percent. Nationally, about 61 percent of ALL patients age 15 to 19 treated between 2000 and 2004 were still alive five years later.
Not only did more patients in the recent therapy era survive, but Ching-Hon Pui, M.D., chair of the St. Jude Department of Oncology and the paper's main author, said they are also less likely to suffer serious late therapy effects, including second cancers and infertility. That is because the regimen, known as Total XV, eliminated or dramatically reduced reliance on drugs linked to those side effects.........
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December 21, 2010, 6:16 AM CT
New breathing therapy reduces panic and anxiety
A new treatment that helps people with panic disorder normalize their breathing works better to reduce panic symptoms and hyperventilation than traditional cognitive therapy, says SMU psychologist Alicia Meuret.
Credit: Hillsman Jackson, SMU
A new therapy program teaches people who suffer from panic disorder how to reduce the terrorizing symptoms by normalizing their breathing.
The method has proved better than traditional cognitive treatment at reducing both symptoms of panic and hyperventilation, as per a newly released study.
The biological-behavioral therapy program is called Capnometry-Assisted Respiratory Training, or CART, said psychology expert and panic disorder expert Alicia E. Meuret at Southern Methodist University in Dallas.
CART helps patients learn to breathe in such a way as to reverse hyperventilation, a highly uncomfortable state where the blood stream operates with abnormally low levels of carbon dioxide, said Meuret, one of the scientists conducting the study.
Hyperventilation, a state of excessive breathing, results from deep or rapid breathing and is common in patients with panic disorders.
"We observed that with CART it's the therapeutic change in carbon dioxide that changes the panic symptoms � and not vice versa," Meuret said.
CART: Breathing exercises twice a day
During the therapy, patients undergo simple breathing exercises twice a day. A portable capnometer device supplies feedback during the exercises on a patient's CO2 levels. The goal of these exercises is to reduce chronic and acute hyperventilation and associated physical symptoms. This is achieved by breathing slower but most importantly more shallowly. Contrary to lay belief, taking deep breaths actually worsens hyperventilation and symptoms.........
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December 16, 2010, 7:54 AM CT
Compound with potent effects on biological clock
Using an automated screening technique developed by pharmaceutical companies to find new drugs, a team of scientists from UC San Diego and three other research institutions has discovered a molecule with the most potent effects ever seen on the biological clock.
Dubbed by the researchers "longdaysin," for its ability to dramatically slow down the biological clock, the new compound and the application of their screening method to the discovery of other clock-shifting chemicals could pave the way for a host of new drugs to treat severe sleep disorders or quickly reset the biological clocks of jet-lagged travelers who regularly travel across multiple time zones.
Typically typically typically "theoretically, longdaysin or a compound like it could be used to correct sleep disorders such as the genetic disorder familial advanced sleep syndrome, which is characterized by a clock that's running too fast," said Steve Kay, dean of UCSD's Division of Biological Sciences, who headed the research team, which published its findings in the December 14 issue of the journal PLoS Biology
"A compound that makes the clock slow down or speed up can also be used to phase-shift the clockin other words, to bump or reset the hands of the clock. This would help your body catch up when it is jet lagged or reset it to a normal day-night cycle when it has been thrown out of phase by shift work".........
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December 16, 2010, 7:31 AM CT
Where unconscious memories form
A small area deep in the brain called the perirhinal cortex is critical for forming unconscious conceptual memories, scientists at the UC Davis Center for Mind and Brain have found.
The perirhinal cortex was believed to be involved, like the neighboring hippocampus, in "declarative" or conscious memories, but the new results show that the picture is more complex, said main author Wei-chun Wang, a graduate student at UC Davis.
The results were published Dec. 9 in the journal Neuron.
We're all familiar with memories that rise from the unconscious mind. Imagine looking at a beach scene, said Wang. A little later, someone mentions surfing, and the beach scene pops back into your head.
Declarative memories, in contrast, are those where we recall being on that beach and watching that surf competition: "I remember being there".
Damage to a structure called the hippocampus affects such declarative "I remember" memories, but not conceptual memories, Wang said. Neuroresearchers had previously thought the same was true for the perirhinal cortex, which is located immediately next to the hippocampus.
Wang and his colleagues carried out memory tests on people diagnosed with amnesia, who had known damage to the perirhinal cortex or other brain areas. They also carried out functional magnetic resonance imaging (fMRI) scans of healthy volunteers while they performed memory tests.........
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December 16, 2010, 7:24 AM CT
Caffeine negatively affects children
Caffeine consumption in children is often blamed for sleep problems and bedwetting. Information on childhood caffeine consumption is limited, and a number of parents may not know the amount or effects of their child's caffeine consumption. As per a research findings published in The Journal of Pediatrics
, scientists observed that 75% of children surveyed consumed caffeine on a daily basis, and the more caffeine the children consumed, the less they slept.
Dr. William Warzak and his colleagues from the University of Nebraska Medical Center surveyed the parents of over 200 children 5 to 12 years old during routine clinical visits at an urban pediatric clinic. Parents were asked to report the types and amounts of snacks and beverages their child consumed on a daily basis.
As per Dr. Warzak, "Some children as young as 5 years old were consuming the equivalent of a can of soda a day." The authors also noticed that the older children drank more caffeinated beverages. "Children between the ages of 8 and 12 years consumed an average of 109 mg a day," Dr. Warzak explains, "the equivalent of almost 3 12-ounce cans of soda." .
Scientists found, however, that caffeine was not associated with bedwetting in these children. "Contrary to popular belief," Dr. Evans, coauthor and statistician, clarifies, "children were not more likely to wet the bed if they consumed caffeine, despite the fact that caffeine is a diuretic." .........
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December 15, 2010, 7:10 AM CT
Fighting flu in newborns begins in pregnancy
A three-year study by Yale School of Medicine scientists has observed that vaccinating pregnant women against influenza is over 90 percent effective in preventing their infants from being hospitalized with influenza in the first six months of life. Reported in the December 15 issue of Clinical Infectious Diseases,
the study builds on preliminary data the research team presented last year at the Infectious Disease Society of America in Philadelphia.
Influenza is a major cause of serious respiratory disease in pregnant women and of hospitalization in infants. Eventhough the flu vaccine is recommended for all pregnant women and children, no vaccine is approved for infants under six months of age. Preventive strategies for this age group include general infection control and vaccination of those coming in close contact with them.
First author Isaac Benowitz, a Yale medical student, senior author Marietta Vazquez, M.D., and their colleagues examined the effectiveness of flu vaccine during pregnancy in preventing hospitalization in infants. The study enrolled infants hospitalized at Yale-New Haven Hospital due to influenza and a similar group of infants without influenza. The scientists then compared whether each infant's mother had gotten the flu vaccine during pregnancy.........
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December 15, 2010, 7:02 AM CT
Breast inflammation is key to cancer growth
PHILADELPHIA It took 12 years and a creation of a highly sophisticated transgenic mouse, but scientists at Kimmel Cancer Center at Jefferson have finally proven a long suspected theory: Inflammation in the breast is key to the development and progression of breast cancer.
In the December 15 issue of Cancer Research,
the researchers say they can now definitively show that an inflammatory process within the breast itself promotes growth of breast cancer stem cells responsible for tumor development.
They also demonstrate that inactivating this inflammation selectively within the breast reduced activity of these stem cells, and stopped breast cancer from forming.
"These studies show for the first time that inactivating the NFKB inflammatory pathway in the breast epithelium blocks the onset and progression of breast cancer in living animals," says Richard G. Pestell, M.D., Ph.D., Director, Kimmel Cancer Center and Chairman of Cancer Biology.
"This finding has clinical implications," says co-author Michael Lisanti, Leader of the Program in Molecular Biology and Genetics of Cancer at Jefferson. "Suppressing the whole body's inflammatory process has side effects. These studies provide the rationale for more selective anti-inflammatory treatment directed just to the breast." .........
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December 15, 2010, 7:01 AM CT
Strategy to improve cancer vaccines
The promise of vaccines targeted against various types of cancer has raised the hopes of patients and their families. The reality, however, is that these promising therapys are difficult to develop. One of the challenges is identifying a discrete cellular target to stop cancer growth without inactivating the immune system. Researchers at UNC Lineberger Comprehensive Cancer Center report a laboratory finding that has the potential to increase the effectiveness of therapeutic cancer vaccines.
The team observed that the absence of the function of a protein called NLRP3 can result in a four-fold increase in a tumor's response to a therapeutic cancer vaccine. If this finding proves consistent, it appears to be a key to making cancer vaccines a realistic therapy option. Their findings were reported in the Dec. 15, 2010 issue of the journal Cancer Research.
Jonathan Serody, MD, a study author, explains, "This finding suggests an unexpected role for NLRP3 in vaccine development and gives us a potentially pharmacologic target to increase vaccine efficacy".
The research team was headed by co-leaders of the UNC Lineberger Immunology Program: Serody, MD, an expert in tumor immunology, and Jenny Ting, PhD, a pioneer in understanding the NLR family of proteins. Serody is the Elizabeth Thomas Professor of Hematology and Oncology. Ting is UNC Alumni Distinguished Professor of Microbiology and Immunology and director of the Inflammation Center at UNC.........
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December 13, 2010, 7:44 AM CT
HOXB7 gene promotes tamoxifen resistance
A gene target for drug resistance, a triple-drug cocktail for triple negative breast cancer, and patients' risk for carpal tunnel syndrome are among study highlights scheduled to be presented by Johns Hopkins Kimmel Cancer Center researchers during the 33rd Annual CTRC-AACR San Antonio Breast Cancer Symposium, held Dec. 8-12. The information is embargoed for the time of presentation at the symposium.
A number of postmenopausal women with early-stage breast cancers who initially respond well to tamoxifen become resistant to the drug over time and develop recurrent tumors. Johns Hopkins Kimmel Cancer Center scientists have observed that a gene called HOXB7 appears to be the culprit in tamoxifen resistance.
Taken by mouth, tamoxifen is used at every stage of breast cancer to treat existing tumors and prevent new ones from developing. The drug works only in women whose tumor cells have a protein, called the estrogen receptor, which binds to the estrogen hormone. Tamoxifen binds to this estrogen receptor and blocks estrogen's effect on fueling cancer cells.
In experiments on cancer cells, the researchers observed that when the HOXB7 gene is overexpressed, as occurs in a number of breast cancers, tumors cells became resistant to tamoxifen. Overexpression of HOXB7 results in proteins that interact with a series of other estrogen-activated genes and proteins, including the HER2 gene, known to make breast cancers aggressive. When the researchers knocked out the HOXB7 gene in one group of breast cancer cells, HER2 activation decreased and the cells became more responsive to tamoxifen. The researchers then showed how the HOXB7-HER2 interaction works.........
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