January 12, 2009, 11:53 PM CT

Cold weather leads to higher blood pressure

Outdoor temperature and blood pressure appear to be correlated in the elderly, with higher rates of high blood pressure in cooler months, as per a report in the January 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Seasonal variations in blood pressure have been recognized among the general population for 40 years, as per background information in the article. However, few prior studies have looked specifically at elderly adults. "Elderly persons appears to be especially susceptible to temperature-related variations in blood pressure," the authors write. "The baroreflex, which is one of the mechanisms of blood pressure regulation, is modified in elderly subjects, and it has been hypothesized that disorders of baroreflex control and enhanced vasoreactivity [sensitivity of blood vessels] could contribute to the aging-associated increase in cardiovascular morbidity [illness]".

Annick Alprovitch, M.D., of the Institut National de la Sant et de la Rcherche Mdicale, Paris, and his colleagues assessed the relationship between blood pressure and temperature in 8,801 individuals 65 or older. All were part of the Three-City study, conducted in three French metropolitan areas. Participants' blood pressure was measured at the beginning of the study (starting in 1999) and again about two years later. Outdoor temperatures on the day of measurement were obtained from local meteorological offices......... Posted by: Daniel      Read more         Source

January 12, 2009, 11:51 PM CT

Stress at workplace may increase risk of stroke

Japanese men in high-stress jobs appear to have an increased risk of stroke compared with those in less demanding positions, as per a report in the January 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Stress is considered a risk factor for stroke, as per background information in the article. Several models of job stress have been developed and provide clues as to how occupational factors appears to be modified to reduce risk. "The job demandcontrol model is the most often used occupational stress model," the authors write. "It posits that workers who face high psychological demands in their occupation and have little control over their work (i.e., those who have job strain) are at a greater risk of becoming ill than are workers with low psychological demands and a high degree of control in their occupation (i.e., those with low-strain occupations)".

Akizumi Tsutsumi, M.D., of the University of Occupational and Environmental Health, Fukuoka, Japan, and his colleagues studied 6,553 Japanese workers (3,190 men and 3,363 women, age 65 and younger) who completed an initial questionnaire and physical examination between 1992 and 1995. The workers were followed up annually through phone calls, letters and interviews for an average of 11 years......... Posted by: Daniel      Read more         Source

January 12, 2009, 11:49 PM CT

Diabetes dementia and brain injuries

Patients with dementia and diabetes appear to display a different pattern of injuries in their brains than patients with dementia but without diabetes, as per an article posted online today that will appear in the March print issue of Archives of Neurology, one of the JAMA/Archives journals.

"The association between diabetes mellitus and increased risk for dementia in the elderly is well documented," the authors write as background information in the article. Several possible mechanisms have been proposed for this association, including the direct effects of high blood glucose and insulin, the build-up of beta-amyloid plaques in the brain and the effects of diabetes-related vascular disease on blood vessels in the brain.

Joshua A. Sonnen, M.D., of the University of Washington, Seattle, and his colleagues studied 196 individuals who were part of the Adult Changes in Thought Study, a community-based investigation of dementia. After the participants died, their brains were autopsied and their cases were divided into four groups based on clinical information: those with diabetes and dementia, those with diabetes but not dementia, those with dementia but not diabetes and those without either disease.

In the 125 patients without dementia, neuropathological and biochemical factors did not differ based on diabetes status. However, among the 71 with dementia, two patterns of injury emerged based on whether the patients had diabetes and received diabetes therapy. Those without diabetes had larger amounts of beta-amyloid buildup and greater free radical damage, whereas those with diabetes had more microvascular infarcts (microscopic injury to small blood vessels in the brain known as arterioles) and more inflammation in neural tissue. This pattern was correlation to diabetes therapy, in that patients with dementia receiving therapy for diabetes had more microvascular infarcts, and untreated diabetic patients with dementia had beta-amyloid build-up similar to non-diabetic patients with dementia......... Posted by: JoAnn      Read more         Source

January 12, 2009, 11:46 PM CT

If you sleep less you catch cold

Individuals who get less than seven hours of sleep per night appear about three times as likely to develop respiratory illness following exposure to a cold virus as those who sleep eight hours or more, as per a report in the January 12 issue of Archives of Internal Medicine, one of the JAMA/Archives journals.

Studies have demonstrated that sleep deprivation impairs some immune function, as per background information in the article. Research indicates that those who sleep approximately seven to eight hours per night have the lowest rates of heart disease illness and death. However, there has previously been little direct evidence that poor sleep increases susceptibility to the common cold.

Sheldon Cohen, Ph.D., of Carnegie Mellon University, Pittsburgh, and his colleagues studied 153 healthy men and women (average age 37) between 2000 and 2004. Participants were interviewed daily over a two-week period, reporting how a number of hours they slept per night, what percentage of their time in bed was spent asleep (sleep efficiency) and whether they felt rested. They were then quarantined and administered nasal drops containing the common-coldcausing rhinovirus. For five days afterward, the study participants reported any signs and symptoms of illness and had mucus samples collected from their nasal passages for virus cultures; about 28 days later, they submitted a blood sample that was tested for antibody responses to the virus......... Posted by: Mark      Read more         Source

January 12, 2009, 11:45 PM CT

A switchboard in the brain helps us learn and remember

The healthy brain is in a constant struggle between learning new experiences and remembering old experiences, a newly released study in this week's PLoS Biology reports. Virtually all social interactions require the rapid exchange of new and old information. For instance, normal conversation requires that while listening to the new information another person is providing, we are already retrieving information in preparation of an appropriate reply. Yet, some memory theories assume that these different modes of memory cannot happen at the same time and compete for priority within our brain.

Brain scientists now provide the first clear evidence supporting a competition between learning and remembering. Their findings also suggest that one brain region can resolve the conflict by improving the rapid switch between learning and remembering. The scientists included Willem Huijbers, Cyriel Pennartz, and Sander Daselaar of the Netherlands' University of Amsterdam, and Roberto Cabeza of Duke University.

The scientists used a novel memory task that forced learning and remembering to occur within a brief period of time. In the study, a group of adults in their 20's looked at a set of regular words presented in the middle of a screen. Participants rapidly tried to remember whether the words had previously been studied or not. Simultaneously, a set of colorful pictures were presented in the background. Meanwhile, the participants' brains were scanned with functional magnetic resonance imaging (fMRI). After brain scanning, participants were surprised with another memory test including the colorful background pictures instead of the words......... Posted by: Daniel      Read more         Source

January 12, 2009, 11:43 PM CT

Younger Adults Could Be At Risk For Heart Disease

Even younger adults who have few short-term risk factors for heart disease may have a higher risk of developing heart disease over their lifetimes, as per new findings by a UT Southwestern Medical Center researcher.

The findings, based on clinical studies and appearing in the Jan. 26 issue of the journal Circulation: Journal of the American Heart Association, suggest that traditional methods of identifying heart disease risk might not adequately identify patients who actually have a higher lifetime risk.

"We observed that about half of individuals who are 50 years of age or younger and at low short-term risk for heart disease may not remain at low risk throughout their lives," said Dr. Jarett Berry, assistant professor of internal medicine at UT Southwestern and main author of the study.

Using current 10-year risk assessment data, more than 90 percent of patients 50 years of age and younger are considered at low risk for heart disease. But when scientists added a lifetime risk model to the 10-year risk model, they observed that about half of those with a low 10-year risk but high lifetime risk had a greater progression of heart disease, as measured by buildup of coronary artery calcium and thickening of the carotid artery.

The short-term (10-year) risk factors in the study were represented by the Framingham Risk Score, a tool typically used by physicians to assess risk for heart disease in patients. Risk factors listed on the assessment include cholesterol levels, blood pressure, smoking, age and gender......... Posted by: Daniel      Read more         Source

January 12, 2009, 11:40 PM CT

New weapon in battle against HIV infection?

Scientists have discovered a potentially important new resistance factor in the battle against HIV: blood types. An international team of scientists from Canadian Blood Services, The Hospital for Sick Children (SickKids) and Lund University in Sweden have discovered that certain blood types are more predisposed to contracting HIV, while others are more effective at fending it off.

A carbohydrate-containing antigen, termed Pk blood group which is distinct from the well-known ABO and Rh blood grouping systems, is present at variable levels on the surface of white and red blood cells in the general population. A study published recently in Blood, which is currently available online, shows that cells from rare individuals (≈ 1 in a million) who produce excess of this blood group antigen have dramatically reduced sensitivity to HIV infection. On the other hand, another slightly more common subgroup of people who do not produce any Pk (≈ 5 in a million) was found to be much more susceptible to the virus.

"This study is not suggesting that your blood type alone determines if you will get HIV," says main author Dr. Don Branch of Canadian Blood Services. "However, it does suggest that individuals who are exposed to the virus, appears to be helped or hindered by their blood status in fighting the infection"......... Posted by: Mark      Read more         Source

January 12, 2009, 11:32 PM CT

New Clues To Understanding Cancer

In the 13th January print edition of the journal Current Biology, Instituto Gubenkian de Ciencia scientists provide insight into an old mystery in cell biology, and offer up new clues to understanding cancer. Ins Cunha Ferreira and Mnica Bettencourt Dias, working with scientists at the universities of Cambridge, UK, and Siena, Italy, unravelled the mystery of how cells count the number of centrosomes, the structure that regulates the cell's skeleton, controls the multiplication of cells, and is often transformed in cancer.

This research addresses an ancient question: how does a cell know how a number of centrosomes it has? It is equally an important question, since both an excess or absence of centrosomes are linked to disease, from infertility to cancer.

Each cell has, at most, two centrosomes. Whenever a cell divides, each centrosome gives rise to a single daughter centrosome, inherited by one of the daughter cells. Thus, there is strict control on progeny! By using the fruit fly, the IGC scientists identified the molecule that is responsible for this 'birth control policy' of the cell a molecule called Slimb. In the absence of Slimb, each mother centrosome can give rise to several daughters in one go, leading to an excess of centrosomes in the cell......... Posted by: Janet      Read more         Source

January 12, 2009, 11:30 PM CT

Nanoparticles based drug delivery system

A tiny particle syringe composed of polymer layers and nanoparticles may provide drug delivery that targets diseased cells without harming the rest of the body, as per a team of chemical engineers. This delivery system could be robust and flexible enough to deliver a variety of substances.

"People probably fear the effects of some therapys more than they fear the disease they treat," says Huda A. Jerri, graduate student, chemical engineering. "The drugs are poison. Treatment is a matter of dosage so that it kills the cancer and not the patient. Targeted therapy becomes very important".

Newer approaches to drug delivery include particles that find specific cells, latch on and release their drugs. Another approach allows the cells to engulf the particles, taking them into the cell and releasing the drug. However, the requirements for these delivery systems are complicated and challenging to implement.

The Penn State researchers' approach produces a more universal delivery system, a tiny spherical container averaging less than 5 microns or the diameter of the smallest pollen grains.

The spheres are formed around solid microparticles that are either the drug to be delivered or a substance that can be removed later leaving a hollow sphere for liquid drugs. They reported their results online in Soft Matter........ Posted by: Scott      Read more         Source

January 12, 2009, 8:40 PM CT

organic substance may help heal broken hearts

Imagine new therapys for heart disease or muscle loss that direct the body to repair damaged tissue rather than helping it cope with a weakened condition. That's not hard to do thanks to Canadian researchers, who for the first time, have developed an organic substance that attracts and supports cells necessary for tissue repair and can be directly injected into problem areas. This development, published online in The FASEB Journal (http://www.fasebj.org) is a major step toward therapys that allow people to more fully recover from injury and disease rather than having to live with chronic health problems. It may even help reduce the need for organ transplantation by allowing physicians to save organs that would have been previously damaged beyond repair.

The "smart scaffolds," developed by Erik Suuronen and colleagues from the University of Ottawa and the Ottawa Heart Research Institute, work because they contain a protein that allows progenitor cells to adhere to the damaged tissue and survive long enough to promote healing. These cells emit homing signals that summon other cells to join in the process and give off chemical signals that order cells to grow blood vessels necessary for healing to occur.

"Ultimately, we envision a scaffold material that can be taken off the shelf and injected into the hearts of patients suffering from blocked arteries," said Suuronen. "The scaffold materials would direct the repair process, and restore blood flow and function to the heart"......... Posted by: Daniel      Read more         Source