Issue 75 / May - June 2010
A New Hope for Type I Diabetes
1- Original Article: Wang, M. et al., PNAS (published online before print on March 1, 2010).
Periodic injections of insulin to manage blood sugar levels is critical for the treatment of diabetes patients. It requires continuous monitoring of glucose levels in the blood and multiple injections of insulin in order to mimic the natural balance of sugar-insulin levels in the human body. Yet, it is often difficult to maintain this extremely sensitive hormone balance without major side effects. These complications include blindness, leg ulcers and amputations, heart vessels problems, renal insufficiency, stroke, and nerve damage in the legs and arms. Moreover, the long-term use of insulin causes the increase of body fat and bad cholesterol. A new research study on non-obese diabetic mice shows that adding leptin- a hormone responsible for appetite control- to the insulin therapy results in better control of blood sugar levels and decreases the bad cholesterol and body fat of Type 1 diabetic mice. This is promising, as it could reduce heart and circulatory complications of Type 1 diabetes. However, the leptin therapy may not have an effect on type 2 diabetes, adult type, because in this type patients already have high levels of leptin. However, it has to be shown that leptin therapy is safe and effective on humans as well. There is a long way to go before we can use leptin in practical areas.
2- Re-teaching speech with music
Original Source: Schlaug G, Annual Meeting of the American Association for the Advancement of Science (AAAS), San Diego (2010).
Nearly 800,000 people in the U.S. are faced with strokes each year, and a quarter of those are affected by aphasia, a deficit in language. Using a new melodic intonation therapy, therapists treat patients by teaching them how to sing words and phrases consistent with the underlying melody of speech. As a result, the patients continue to speak in a more "sing-songy" way than a person with normal speech patterns, according to Dr. Schlaug, professor of neurology at Harvard Medical School. After 15 weeks, 1.5 hour-long daily sessions with a therapist, the patients gradually learn to piece the sung words together into organized speech. There are two separate brain networks associated with vocal output, with the one in the left hemisphere being engaged with speech and the other one in the right hemisphere strongly responding to music and melody. For the stroke patients that had damage to the left hemisphere, this therapy may help to train similar areas on the right hemisphere, helping them to initiate a speech region in the right hemisphere. Singing facilitates necessary engagement to the right hemisphere. Images of patients' brains before and after the therapy reveal striking structural and functional changes in the right hemisphere. This study also reminds us of the brilliance of musical therapies employed in early hospitals in the Islamic world.
3- Renewable Jet-Fuels
Original Article: Bond, J.Q. et al., Science 327, 1110 (2010).
The global need for sustainable energy resources is ever increasing and the use of renewable fuels offer promising solutions. Among others, biofuels are especially important due to the presence of direct conversion routes from plant-based waste materials to conventional liquid fuels. However, high synthesis costs and complex processing steps are major hurdles to overcome before putting biofuels forward as economically viable alternatives to fossil fuels. Researchers are therefore trying to come up with more efficient methods -and one group, from the University of Wisconsin appears to have done so. Unlike commonly utilized routes involving microorganisms, they use a novel and environmentally-friendly chemical process which is easier to control and maintain. By using an inexpensive catalyst, they convert the majority of the wasted biomass to gaseous butene and carbon dioxide, with a water-based solution of gamma valerolactone as the intermediate chemical. The butene gas is then easily transformed to high-energy transportation fuels such as gasoline and jet fuel. As an added advantage, the stream of carbon dioxide can be efficiently captured, preventing the atmospheric release of this major greenhouse gas. Under optimized conditions, the system can operate uninterrupted for 90 hours with an overall efficiency of over 75%. Successful work like this will help make biofuels cheaper for mass production, pending the meticulous analysis of its economics.
4- Salt controversy: How much is too much?
Original Article: Bibbins-Domingo, K. et al., NEJM 362, 590 (2010).
Modern humans suffer from high rates of obesity (for instance, 64% of Americans are classified as either overweight or obese) and cardiovascular diseases, with the latter being the no.1 cause of all deaths. A recent study conducted by researchers at the University of California at San Francisco suggests that reducing dietary salt by half a teaspoon a day (~ 3g) would lower the annual number of new coronary heart disease, stroke and myocardial infarction cases. Strikingly, such a modest decrease is expected to decrease deaths from any cause by 44,000 to 92,000. According to the National Salt Reduction Initiative, Americans eat at least twice as much salt as they need where 80 percent of the salt in the American diet comes from processed or restaurant-prepared foods. However, eating too much salt is not a problem for people with healthy kidneys since kidneys are designed to flush out unneeded salt. However, when people have a high salt diet, then their kidneys are over-worked. Taking into account that modest salt reduction in one‚Äôs diet won‚Äôt likely cause harm and taste buds will likely adapt to this minor change effortlessly, it seems wise to refrain from using too much salt. This would trigger bigger health benefits ranging from not overworking the kidneys to reducing the risk of deadly diseases.
5- Why don‚Äôt we get thirsty during sleep?
Original Article: Trudel, E. & Bourque, C.W., Nature Neuroscience (published online before print on February 28, 2010).
In mammals, the ‚Äúinternal-standard-time‚ÄĚ is kept by a particular subset of brain cells known as ‚Äúclock-neurons‚ÄĚ which display high activity during the day and low activity during the night. A group of scientists recently reported that the clock-neurons also function as a dimmer for water regulation, allowing bodily water content to be controlled by the body. A specialized group of cells, called osmo-sensory-neurons, detect and regulate water levels in the body, through balancing the water intake via thirst and loss via urine production. When water levels are low, the sensory-neurons communicate with some hormone-releasing cells which instruct the body to store water by ceasing urine production. By using isolated brain slices from rats, the researchers showed that the clock-neurons ‚Äď when active ‚Äď interfere with the communication between sensory-neurons and hormone-releasing-cells to suppress the water-storage-hormone release. In contrast, when the clock-cells are inactive (i.e., ‚Äėsleep period‚Äô) the communication is restored, resulting in an increase of hormone levels to enable water-storage. Such regulation is the reason why we are not much disturbed during sleep by neither frequent trips to the bathroom, nor excessive thirst (that would both impair the sleep quality), and reminds us the verse from the Holy Qur‚Äôan: ‚Äú..and He has made the night for rest‚Ä¶‚ÄĚ (Chapter Al-Anaam, 96).
6- A passage to vegetative state through fMRI
Original Article: Monti MM et al., NEJM 362, 579 (2010).
Consciousness in medicine is defined as the patient‚Äôs alertness and responsiveness to the outside world. If a patient does not respond to external stimuli, his/her medical state is considered a ‚Äúvegetative state‚ÄĚ. Researchers from Cambridge, England performed functional magnetic resonance imaging (fMRI) experiments on 54 patients who had been previously classified as either ‚Äúvegetative‚ÄĚ or ‚Äúminimally conscious‚ÄĚ. Interestingly, 5 of 54 patients exhibited distinct neuronal activities in the corresponding regions of their brains, when they are given imaginary motor and spatial tasks. For the motor task, patients are asked to imagine playing a tennis game. For the spatial task, patients are asked to imagine navigating through a familiar location. A 22 year-old man who had been in coma for five months was further evaluated by being subjected to a simple set of yes-or-no questions such as ‚ÄúDo you have any brothers?‚ÄĚ and was instructed to answer these questions using one type of mental imagery, that is a motor imagery for ‚ÄúYes‚ÄĚ and a spatial imagery for ‚ÄúNo‚ÄĚ. He answered 5 out of 6 questions correctly. This is the first evidence that through fMRI approach one can reach the residual cognitive activity in vegetative patients and establish functional communication, raising question marks about our current handling of these so-called vegetative patients.