Tuesday, 26 December 2006

Brain chemical linked to alcohol desire

Australian scientists have identified a brain system that could not only blunt an alcoholic's craving for booze, but also the addiction.

The BBC reported Monday researchers at Melbourne's Howard Florey Institute discovered how to block the action of the brain's orexin system, which can also stop the desire for alcohol in its tracks.

Orexin cells, also known as hypocretins, are a pair of highly excitatory neuropeptides found in the brain. The chemical is involved in the "high" felt after drinking alcohol or taking illicit drugs or even eating a great meal.

Dr. Andrew Lawrence used a drug that actually blocked orexin's euphoric effects in the brain. Test rats, in fact, turned their noses up when faced with the oportunity of swilling unlimited alcohol, even those that had gone through detox chose to not imbibe.

"Orexin reinforces the euphoria felt when drinking alcohol, so if a drug can be developed to block the orexin system in humans, we should be able to stop an alcoholic's craving for alcohol," Lawrence told the BBC.

Copyright 2006 by United Press International. All Rights Reserved. via ScienceDaily

Measuring Pandemic Preparedness: Vaccination Campaigns Need A Shot In The Arm

A federal plan to vaccinate hospital healthcare workers against a threat of smallpox fell short on several levels, according to the first metric analysis of the prophylactic health program. Results of the Temple University study raise troubling questions about future preparedness against possible outbreaks of avian flu or SARS.

The study, "Preparedness for a smallpox outbreak: comparing metrics for assessing levels of vaccination among health-care workers by state," has been published online ahead of print in the journal Epidemiology and Infection.

In 2003, the Centers for Disease Control and Prevention asked each state to vaccinate at least 50 to100 healthcare workers per hospital, a number the government considered large enough to respond to a possible smallpox outbreak. These workers could then vaccinate and treat others.

Doses of smallpox vaccine were distributed nationally based on each state's requests, with a goal of vaccinating 500,000 workers in 30 days. Yet by mid-2005, only about 39,000 -- or 17 percent of the requested dosages -- had been used.

"Some states requested thousands of vaccines, while others only a few hundred," said lead researcher Sarah Bass, Ph.D., MPH, assistant professor of public health in Temple University's College of Health Professions.

To critically examine how well the program worked, researchers analyzed vaccination patterns based on a series of metrics: the absolute numbers of health care workers vaccinated compared to the percentage of doses distributed to each state, the rate of vaccination per capita population, and the percentage of healthcare workers vaccinated compared to the number recommended by the CDC. States were then ranked into four quartiles.

"We had to do a very careful analysis because some states appeared to have a very high vaccination rate if you only looked at the number of absolute vaccinations as a percentage of the number of vaccines requested," Bass said.

Oklahoma, for example, vaccinated 376 people with the 700 doses requested -- slightly more than 50 percent. However, the state would have needed an estimated 9,675 doses to meet the CDC's recommendations, which leaves Oklahoma's true vaccination rate only at 3.9 percent of the goal set by the CDC.

Overall, researchers found a generally low compliance rate along with a great variability among states. States most affected by 9/11-- New York, Pennsylvania and Virginia -- ranked in the bottom quartiles of most metrics, while several states perceived to be at a lower terror risk, such as Nebraska, ranked at the top.

While the lack of an impending smallpox crisis may account for the differences in state response, both the federal and state governments could have done a better job, Bass said.

"Some felt the CDC or state health departments sent ambivalent messages about the importance of the program, and many states did not fully support the effort," Bass said. "The result was a very inconsistent uptake of the vaccination program by states, where some states had very coordinated efforts and others did not."

Adding to the variability were many healthcare workers who didn't believe that the benefits of the vaccine outweighed the personal risks.

"Workers worried that the vaccine, which had not been given to middle-aged or older adults in the past, might have unanticipated dangers. Others wondered if the vaccine might be effective against newer forms of weaponized smallpox," said Bass.

To uncover why healthcare workers did not accept vaccines, Bass, along with colleagues Tom Gordon and Sheryl Ruzek, is working on a new study that employs perceptual mapping to evaluate how healthcare workers balance risks and benefits in deciding whether or not to take part in a vaccination program.

"To be prepared, we need to have health workers protected," Bass said. "But as long as it's a decentralized program without an immediate outbreak, it will be difficult."

Note: This story has been adapted from a news release issued by Temple University. via Science Daily

Abnormal Proteins Linked To Schizophrenia Found In Body Tissue

A new study suggests biochemical changes associated with schizophrenia aren't limited to the central nervous system and that the disease could have more encompassing effects throughout the body than previously thought. The findings, scheduled for publication in the January 2007 issue of the American Chemical Society's Journal of Proteome Research, could lead to better diagnostic testing for the disease and could help explain why those afflicted with it are more prone to type II diabetes, cardiovascular diseases and other chronic health problems.

Researcher Sabine Bahn, M.D., Ph.D., and her colleagues at Cambridge University in England and the University of Cologne in Germany, detected abnormal proteins linked to schizophrenia in the liver and red blood cells of people who have the disorder. It is the first time the same altered proteins have been detected both within brain tissue as well as in non-brain tissue, according to Bahn.

In time, Bahn says, these protein "biomarkers" could be used to trace the progression of the disease throughout the body.

"If changes in the rest of the body can be observed, and if these changes reflect what is going wrong in the brain, we can use these (findings) to learn about the cellular dysfunction that causes schizophrenia and this will allow us to develop better drugs and diagnostics," Bahn says.

About 1 percent of the world's population -- including 2.4 million Americans -- has schizophrenia, a complex and puzzling mental illness that can lead to delusions, hallucinations and disordered thinking. It is one of the world's most common causes of psychosis, according to Bahn. Since it was first described more than 100 years ago, scientists have made little progress in unraveling the causes of the disease, and no definitive test is available to diagnosis it, she says.

"We desperately need a better understanding of this illness. It is, however, difficult to study the disease, as the brain can't easily be investigated. We can't take multiple biopsies from patients to look at the disease-related changes," Bahn says. "We need a new concept."

While most scientists investigating the disease believe it only affects the brain, Bahn notes that researchers have long known that people who have schizophrenia are at higher risk than the general population for a number of chronic diseases. Some evidence suggests these health problems might be somehow tied to schizophrenia, she adds, but most studies have been inconclusive. Bahn's latest discovery could help bridge this gap.

Recently, Bahn and her colleagues discovered a set of abnormal proteins in post-mortem brains of people who had schizophrenia. In this new study, they sought to detect similarly altered proteins in other organs and tissues of individuals living with the disease. After looking at thousands of proteins, they found that people with schizophrenia had 14 liver proteins and eight red blood cell proteins that were significantly altered compared to individuals who didn't have the disease. These altered proteins were strikingly like those found in the post-mortem brains.

Several of these abnormal proteins appear to promote oxidative stress and disrupt energy metabolism in cells, Bahn says. She theorizes that schizophrenia is caused, at least in part, by these two problems. In her earlier work, for instance, Bahn found evidence that schizophrenic brains might have difficulty producing or using energy properly and are more susceptible to cell-damaging free radicals than healthy brains. The new findings, she says, suggest that the same sort of energy starvation, increased free-radical damage cycle could be occurring in other tissue and, in addition to schizophrenia, possibly be contributing to the onset of other chronic diseases.

Note: This story has been adapted from a news release issued by American Chemical Society. via Science Daily

Five New Technologies That Promise To Transform Medicine

Fat zapping to shed excess weight, miniature telescopes to restore vision, and smart nappies to detect common childhood infections: these are some of the new technologies that promise to transform medicine, according to this week's Christmas issue of the British Medical Journal.

The forecasts are made by Professor Donald Combs of the Eastern Virginia Medical School and are based on existing technologies that are in varying stages of development and on extensions of those technologies.

His vision for the future includes airport x-ray style devices that "fry" excess fat with a laser. An overweight patient simply walks through the device and emerges several pounds lighter. No side effects are seen apart from the resizing of his wardrobe.

Patients with chronic diseases who need regular medication will benefit from a miniature implant that monitors and transmits data on heart and breathing rates, blood pressure, and blood sugar levels. And further into the future are links smart pumps that, when signalled, instantly deliver the correct medication.

Another prediction is the use of miniature telescopes that restore vision for patients with degenerative eye disease. The telescopes are powered by sunlight passing through the pupils to microscopic solar battery panels attached to the retinas.

These scenarios illustrate potential clinical applications of technologies currently under development, says Professor Combs. For instance, devices that can sense and transmit heart and breathing rates already exist and implantable lenses are well-known.

Other emerging technologies include wave technology to isolate cancer cells, fabrication technology to manufacture customised body parts, and the use of miniature robots to track and destroy infections before they cause disease.

The individual and collective impact of these technologies is already present in some aspects of contemporary medicine and the rate of their impact is increasing, he concludes.

Note: This story has been adapted from a news release issued by BMJ-British Medical Journal. via Science Daily

New Neurons Could Act To Alleviate Epilepsy

cience Daily The new neurons generated as a result of neural damage due to epilepsy show a reduced excitability that could alleviate the disorder, researchers have found. The researchers said their results suggest that therapies for epilepsy aimed at inducing neurogenesis could prove effective in alleviating the disorder.

In an article in the December 21, 2006, issue of the journal Neuron, published by Cell Press, Olle Lindvall and colleagues at Lund University Hospital and Stem Cell Center described studies in rats examining neurons generated after an epileptic event has been triggered in the animals.

In their experiments, the researchers compared the properties of new neurons generated in rats allowed to exercise by running on a wheel with those in rats in which epileptic seizures were induced by electrical brain stimulation. Specifically, the researchers analyzed the electrical properties of a type of new cells, called granule cells, in the structure called the dentate gyrus of the hippocampus. This structure is known to be a "gate" for propagation of seizures in the hippocampus, a center for learning and memory.

The scientists' analysis showed that the new neurons in both the runners and the epileptic animals had all the characteristics of mature dentate gyrus cells. However, they found that neurons born into an epileptic environment, compared to the physiological running environment, showed reduced excitatory connectivity to other neurons, as well as increased inhibitory connectivity. Such differences could mean the newly generated neurons "could have significant beneficial effect on the epileptic syndrome," concluded the researchers.

"Our study demonstrates that both a physiological stimulus and an insult to the adult brain trigger the formation of new dentate granule cells, which are functionally integrated into hippocampal neural circuitry," concluded Lindvall and colleagues. They wrote that "following insult, the functional connectivity of new neurons seems to develop in order to mitigate the dysfunction in the epileptic brain. These data provide further evidence for a therapeutic potential of endogenous neurogenesis."

The researchers include Katherine Jakubs, Avtandil Nanobashvili, Sara Bonde, Christine T. Ekdahl, Zaal Kokaia, Merab Kokaia, and Olle Lindvall of Lund University Hospital and Stem Cell Center in Lund, Sweden.

This work was supported by Swedish Research Council, EU project LSHBCT-2003-503005 (EUROSTEMCELL), and Söderberg, Crafoord, and Kock Foundations. Lund Stem Cell Center is supported by a Center of Excellence grant in Life Sciences from Swedish Foundation for Strategic Research.

Jakubs et al.: "Environment Matters: Synaptic Properties of Neurons Born in the Epileptic Adult Brain Develop to Reduce Excitability." Publishing in Neuron 52, 1047--1059, December 21, 2006 DOI 10.1016/j.neuron.2006.11.004. http://www.neuron.org

Note: This story has been adapted from a news release issued by Cell Press.

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