Rush University Medical Center

Sudden decline in male testosterone may cause Parkinson’s disease.

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The results of a new study by neurological researchers at Rush University Medical Center show that a sudden decrease of testosterone, the male sex hormone, may cause Parkinson’s like symptoms in male mice. The findings were recently published in the Journal of Biological Chemistry.

One of the major roadblocks for discovering drugs against Parkinson’s disease is the unavailability of a reliable animal model for this disease.

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“While scientists use different toxins and a number of complex genetic approaches to model Parkinson’s disease in mice, we have found that the sudden drop in the levels of testosterone following castration is sufficient to cause persistent Parkinson’s like pathology and symptoms in male mice,” said Dr. Kalipada Pahan, lead author of the study and the Floyd A. Davis endowed professor of neurology at Rush. “We found that the supplementation of testosterone in the form of 5-alpha dihydrotestosterone (DHT) pellets reverses Parkinson’s pathology in male mice.”

“In men, testosterone levels are intimately coupled to many disease processes,” said Pahan. Typically, in healthy males, testosterone level is the maximum in the mid-30s, which then drop about one percent each year. However, testosterone levels may dip drastically due to stress or sudden turn of other life events, which may make somebody more vulnerable to Parkinson’s disease.

“Therefore, preservation of testosterone in males may be an important step to become resistant to Parkinson’s disease,” said Pahan.

Understanding how the disease works is important to developing effective drugs that protect the brain and stop the progression of Parkinson’s disease. Nitric oxide is an important molecule for our brain and the body.

“However, when nitric oxide is produced within the brain in excess by a protein called inducible nitric oxide synthase, neurons start dying,” said Pahan.

“This study has become more fascinating than we thought,” said Pahan. “After castration, levels of inducible nitric oxide synthase (iNOS) and nitric oxide go up in the brain dramatically. Interestingly, castration does not cause Parkinson’s like symptoms in male mice deficient in iNOS gene, indicating that loss of testosterone causes symptoms via increased nitric oxide production.”

“Further research must be conducted to see how we could potentially target testosterone levels in human males in order to find a viable treatment,” said Pahan.S

Source: http://machineslikeus.com

 

Being a Lifelong Bookworm May Keep You Sharp in Old Age.

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To keep their bodies running at peak performance, people often hit the gym, pounding away at the treadmill to strengthen muscles and build endurance. This dedication has enormous benefits—being in shape now means warding off a host of diseases when you get older. But does the brain work in the same way? That is, can doing mental exercises help your mind stay just as sharp in old age?

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Experts say it’s possible. As a corollary to working out, people have begun joining brain gyms to flex their mental muscles. For a monthly fee of around $15, websites like Lumosity.com and MyBrainTrainer.com promise to enhance memory, attention and other mental processes through a series of games and brain teasers. Such ready-made mind exercises are an alluring route for people who worry about their ticking clock. But there’s no need to slap down the money right away—new research suggests the secret to preserving mental agility may lie in simply cracking open a book.

The findings, published online today in Neurology, suggest that reading books, writing and engaging in other similar brain-stimulating activities slows down cognitive decline in old age, independent of common age-related neurodegenerative diseases. In particular, people who participated in mentally stimulating activities over their lifetimes, both in young, middle and old age, had a slower rate of decline in memory and other mental capacities than those who did not.

Researchers used an array of tests to measure 294 people’s memory and thinking every year for six years years. Participants also answered a questionnaire about their reading and writing habits, from childhood to adulthood to advanced age. Following the participants’ deaths at an average age of 89, researchers examined their brains for evidence of the physical signs of dementia, such as lesions,plaques and tangles. Such brain abnormalities are most common in older people, causing them to experience memory lapses. They proliferate in the brains of people with Alzheimer’s disease, leading to memory and thinking impairments that can severely affect victims’ daily lives.

Using information from the questionnaire and autopsy results, the researchers found that any reading and writing is better than none at all. Remaining a bookworm into old age reduced the rate of memory decline by 32 percent compared to engaging in average mental activity. Those who didn’t read or write often later in life did even worse: their memory decline was 48 percent faster than people who spent an average amount of time on these activities.

The researchers found that mental activity accounted for nearly 15 percent of the difference in memory decline, beyond what could be explained by the presence of plaque buildup. “Based on this, we shouldn’t underestimate the effects of everyday activities, such as reading and writing, on our children, ourselves and our parents or grandparents,” says study author Robert S. Wilson, a neuropsychologist at the Rush University Medical Center in Chicago, in a statement.

Reading gives our brains a workout because comprehending text requires more mental energy than, for example, processing an image on a television screen. Reading exercises our working memory, which actively processes and stores new information as it comes. Eventually, that information gets transferred into long-term memory, where our understanding of any given material deepens. Writing can be likened to practice: the more we rehearse the perfect squat, the better our form becomes, tightening all the right muscles. Writing helps us consolidate new information for the times we may need to recall it, which boosts our memory skills.

So the key to keeping our brains sharp for the long haul does have something in common with physical exercise: we have to stick with it. And it’s best to start early. In 2009, a seven-year studyof 2,000 healthy individuals aged 18 to 60 found that mental agility peaks at 22. By 27, mental processes like reasoning, spatial visualization and speed of thought began to decline.

Source: Smithsonian.com