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Exercise Before Alcohol

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Rigorous physical exercise before binge drinking may reduce brain damage in adolescents.
…..
Monkeys are much like humans. If you leave them alone with alcohol, some of them are sure to get drunk quickly. But that’s a useful trait, because then you can study their brains easily. Scientists at the Scripps Research Institute near San Diego in the US did exactly that with adolescent monkeys, and came to some disturbing conclusions.

Chitra Mandyam and her colleagues at the Scripps Institute were investigating the effects of binge drinking among adolescents. They let the monkeys drink for an hour every day for 11 months. They then stopped the alcohol supply for two months, after which they examined the brains of the animals. The monkeys showed permanent damage in the hippocampus, an area that is crucial to the formation of new memory.

Adolescence — whether in rats, monkeys or humans — is a period of intense physical and mental change. “It is a vulnerable period,” says Mandyam.

According to several studies, binge drinking is increasing among adolescents. Over 60 per cent of these youngsters are at risk of developing brain disorders. It is thus necessary to understand how alcohol damages the brain, how lasting the damage is, and what can be done to reverse it.

“There have been several studies on rodents,” says Mandyam. “But this is the first time we studied binge drinking in monkeys.” There are many advantages of studying the phenomenon in monkeys. The animals are genetically similar to human beings, they drink like humans, and their brains are affected in a manner similar to that in humans.

Neurons in the hippocampus are generated the same way in monkeys as in humans. Since it is difficult to get the brains of adolescent humans for post-mortem, monkeys form the closest approximation for studying the effect of alcohol on adolescent humans.

Scientists at the Scripps Institute first selected a set of monkeys who liked to drink alcohol, and then divided it into two groups. One group was allowed to drink for 11 months and the other did not get to drink. Neurons in the hippocampus of the animals that drank had degenerated when seen even after two months of abstinence. The level of stem cells in the brain also decreased, suggesting the brain had less capacity to repair the damage.

The hippocampus is an important area of the brain that is involved in several functions like spatial memory formation, executive functioning and short-term and long-term memory formation. If damaged during adolescence, it could affect an individual’s functioning for a lifetime. This is particularly true if the stem cells are damaged. Mandyam’s study showed that as much as 90 per cent of the stem cells in the hippocampus could be damaged by binge drinking.

So the next question is: what can we do to reverse the damage? The brain is known to be very plastic, but can we invoke this plasticity when the stem cells in the hippocampus are damaged? There are no studies of monkeys, but those of rats suggest that one may be able to control this damage partly.

One particular study by Kimberly Nixon and her colleagues at the University of Kentucky in the US has shown that exercise before drinking may reduce the damage to a certain extent.

Nixon made rats exercise voluntarily for 14 days before four days of intense drinking. When the brains of the rodents were examined after that, they showed reduced damage compared with rats that did not exercise. However, we cannot necessarily conclude that all alcohol damage is reversible. “We do not know the threshold levels alcohol begins to be toxic,” says Nixon. “There is old data saying that over 50 per cent of alcoholics have persistent cognitive defects they never recover from.”

There may be several reasons why exercise shows reduced damage. It could be that the brain cells form new connections to compensate for lost cells. Abstinence and the passage of time may help the brain recover a bit. But we still do not know the many ways in which alcohol affects the brain.

However, we do know two things: binge drinking can permanently damage parts of the brain. And a period of exercise before drinking can prevent or at least reduce brain cell death.


Source :
The Telegraph ( Kolkata, India)

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High on Calories

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Obese people are not able to regulate high-calorie food intake because of changes in their brain.
CLICK & SEE
If your overweight children binge eat, blame it on their flawed brain circuitry. Scientists have now found that despite the desire to cut their food intake, obese individuals will not be able resist junk food, which is very high in calories. That’s because their persistent eating behaviour has precipitated changes in the brain similar to that found in heavy smokers and drug addicts. The study appeared yesterday in the journal Nature Neuroscience.

After spending years studying brain changes associated with drug abuse and smoking, Paul Kenny — a neurobiologist at the Scripps Research Institute in Florida, the US — recently turned his attention to obesity. He and his graduate student, Pal Johnson, wanted to understand the strong yet not-so-easy-to-fathom link between obesity and depleted levels of dopamine or D2, a brain chemical associated with feelings of pleasure.

Scientists in the past had observed that obese individuals have reduced levels of dopamine, but weren’t sure if it was triggered by obesity. It was also known that food intake was associated with dopamine release and the degree of pleasure from eating correlates with the amount of chemical released. Evidence has shown that in comparison to lean people, obese individuals have fewer dopamine receptors in the brain. And people with fewer dopamine receptors need to take in more of a rewarding substance — such as food or drugs — to get an effect that others get with a lesser amount. But the underlying mechanisms are poorly understood.

“What we have achieved is proven in our experiments with laboratory rats that obesity can elicit these brain changes,” Kenny told KnowHow over the telephone.

For this, the Florida scientists embarked upon a series of meticulously planned experiments. In the first, they offered rats — which were grouped into three categories — different menus. While the first group had access solely to less-appetising but healthier chow, the other two were offered a choice of high-calorie food such as bacon, sausage, cake and chocolate in addition to chow, but for varying durations. Some rats had access to the rich fare for just one hour, while the other group could gorge on it most part of the day. The animals were fed this way for 40 days. All of them were wired to record even the slightest change in their D2 levels.

The rats in the first set — which were fed only chow — maintained their weight, while those belonging to the second set — which had restricted access to rich food — exhibited insignificant increase in their body weight. On the contrary, the third group — which had unlimited access to calorie-rich food — gained weight rapidly. These animals were found to be gobbling up twice as much as the other two groups. As the days wore on, their dopamine levels plummeted, requiring them to consume higher quantities of high-fat food to get the feeling of satiation. This is quite like the case of a smoker who has to puff away more cigarettes to get the same high that he or she earlier got with one. Or a drug addict who has to continuously increase the dose for getting a kick.

A second set of experiments with the rats showed that this blunting of the reward sensitivity does not return for a good two weeks even after the high-calorie food was withdrawn.

A true addict, whether rat or human, will compulsively consume the addictive substance even when it is clearly detrimental to health. In the third experiment the scientists tested this hypothesis. To do this, the team trained the rats to expect painful foot shocks upon seeing a light signal. Although the normal rats stopped eating even the most delicious junk food when the light came on, the obese ones used to a high-calorie diet simply ignored the cue and kept feeding.

Anoop Misra, head of internal medicine at Fortis Hospitals in New Delhi, says this explains why obese people find it difficult to modulate their junk food eating habits.

“The US scientists’ experiment has substantiated many assumptions associated with obesity and dopamine levels in the brain fairly well,” says Nihal Thomas, an endocrinologist at the Christian Medical College, Vellore. “The exercise and methodology followed are exquisite.” The findings may help develop drugs that may target dopamine receptors to treat obesity, he observes.

Source : The Telegraph (Kolkata, India)

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Diagnonistic Test

Fluorescein Angiography (Test for Diabetic Retinopathy)

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Alternative Names: Retinal photography; Eye angiography

Definition:
Fluorescein angiography is an eye test that uses an special dye and camera to look at blood flow in the retina and choroid……...CLICK & SEE

By looking into the back of your eye (the retina), eye doctors can see changes in the blood vessels there that show whether you are at risk for losing vision from diabetes or other causes. The earliest changes can be seen only with a special test called fluorescein angiography. For this test, a chemical that temporarily makes the blood vessels fluorescent and shows very tiny leaks in them is injected into one of your arm or hand veins while you are having your eyes examined.

This test is used to determine if there is proper circulation in the blood vessels of the retina. It can also be used to diagnose problems in the eye or to determine how well treatment is working.

Preparation  for the test:
You should arrange to have someone else drive you home from the eye doctor, because your eyes will be dilated; this can make your eyes sensitive to the sun and your vision blurry for a while.

You may be told to discontinue drugs that could affect the test. results. Tell your health care provide about any allergies, particularly reactions to iodine.

You must sign an informed consent form. You must remove contact lenses before the test.

Tell the health care provider if you may be pregnant.


How the Test Is Performed

Eye drops that make the pupil dilate will be given. You will be asked to place your chin on a chin rest, and your forehead against a support bar to keep your head still during the test.

Fluorescein angiography->…..CLICK & SEE

The health care provider will take pictures of the inside of your eye. After the first group of pictures are taken, a special dye called fluorescein is injected into your vein, usually at the bend of the elbow. A special camera takes pictures of the dye as it moves through the blood vessels in the back of the eye.

More photographs are taken up to 20 minutes after the injection.

What happens when the test is performed?
You have drops put into your eye to make the pupil dilate (open), and you have to wait for about half an hour while the drops take effect. Before giving you any other medicine, your doctor might first examine your eyes for signs of bleeding or debris outside of your retina arteries; these are signs of more advanced eye disease from diabetes. Then a nurse inserts a small needle into one of the veins in your arm or hand so that you can have a dose of medicine injected. Your doctor uses a special eye camera to take pictures of your retina. You look into one side of the camera while your doctor looks through the other side. The camera shines a dim blue light into your eye, which causes the dye flowing through the retina arteries to show up as fluorescent green. The doctor takes a collection of pictures of your eyes to review more closely later.

This color retinal photograph demonstrates nonproliferative diabetic retinopathy. The image is centered on the macula (the part of the retina responsible for central fine vision) with part of the optic nerve seen on the left of the photo (left eye). There are hemorrhages within the retinal tissue on the right side of the photograph.

How the Test Will Feel
When the needle is inserted , some people feel moderate pain, while others feel only a prick or stinging sensation. Afterward, there may be some throbbing.

When the dye is injected, you may have mild nausea and a warm sensation. These symptoms are usually very brief.

Normal Results:
A normal result means the vessels appear a normal size and there are no blockages or leakages.
Back to TopWhat Abnormal Results Mean
If blockage or leakage is present, the pictures will map the location for possible treatment.

An abnormal value on a fluorescein angiography may be due to:

*Blood flow (circulatory) problems
*Cancer
*Diabetic or other retinopathy
*Inflammation or edema
*Macular degeneration
*Microaneurysms — enlargement of capillaries in the retina
*Tumors
*Swelling of the optic disc

Additional conditions under which the test may be performed:

Retinal detachment
Retinal vessel occlusion
Retinitis pigmentosa

Risk Factors:
There are no special risks from this test, although your vision may be blurry for an hour or more after the test because your pupils are dilated. The dye fluorescein is excreted from your body in your urine, which might give your urine a bright or discolored appearance for a day.

There is a slight chance of infection any time the skin is broken. Rarely, a person is hypersensitive to the dye and may experience:

*Dizziness or faintness
*Dry mouth or increased salivation
*Hives
*Increased heart rate
*Metallic taste in mouth
*Nausea and vomiting
*Sneezing
*Serious allergic reactions are rare.

Your urine will be darker, and possibly orange in color, for a day or two after the test.

Must you do  after the test is over?

You will need to wear sunglasses for a few hours until your pupils are no longer dilated.

Considerations:
People with cataracts will have less accurate test results.

How long is it before the result of the test is known?
Your doctor can often discuss the results of the test with you at the end of your visit. He or she might recommend treatment (such as eye laser treatments) if your test reveals retina disease.

Click to see:->How does diabetes affect the retina?

Resources:
https://www.health.harvard.edu/diagnostic-tests/fluorescein-angiography.htm
http://health.nytimes.com/health/guides/test/fluorescein-angiography/overview.html

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News on Health & Science

Drink To Remember

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Alcohol in moderate quantities challenges the brain, thus improving memory, reports Roger Highfield

A glass or two of wine can boost our ability to remember, says a new study. Scientists have found that moderate amounts of alcohol challenge the brain and it responds by improving the memory…..…CLICK & SEE

The findings rubbished the notion of drinking to forget, as they also show drinking enough to exceed the limit for driving means you are more likely to remember the embarrassment of a boisterous binge   from making an indecent proposal to dancing without your trousers on.

“Contrary to popular belief, we also found that excessive levels of alcohol enhanced memories of highly emotional stimuli,   said Prof. Matthew During of the University of Auckland, New Zealand.

“Our work suggests that heavy drinking actually reinforces negative memories.”

With Dr Maggie Kalev, he studied the effects on memory of moderate levels of alcohol consumption, equivalent to a glass or two of wine a day, and found they can enhance memory.

Moderate levels of alcohol challenge the brain and it responds by improving memory, said During.   It is like the best way to build strength in a muscle is to challenge the muscle. But you have to get it just right.

Kalev added that low levels of alcohol “promoted neutral memories, such as remembering objects”. The research has been published in the Journal of Neuroscience.

An earlier study by scientists from The Scripps Research Institute in La Jolla, California, suggested that alcohol affects our memory for details more than our memory of a major event.

That suggested why, after recovering from a binge, one may not remember dancing on a table, or much about the place where the drinking occurred. However, you may still have a lingering feeling that a good (or bad) time was had.

Source: The Telegraph (Kolkata, India)

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News on Health & Science

Could Stem Cells Make You More Beautiful?

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Stem Cells Could Have Cosmetic Applications, but They’re Likely Far Off.

The prospect is a tantalizing one. To erase wrinkles and fine lines, or to get bigger breasts, without cosmetic surgery. Forget silicone, forget collagen. All you would need is stem-cell therapy.

Realistically speaking, though, such applications remain a pipe dream.

Of course, it wouldn’t be the first time a medical therapy had been bent in the direction of aesthetics. Take a look at Botox   the deadly botulinum toxin initially used to treat spasms is now used to improve the appearance of frown lines.

And while stem-cell applications for the vanity market may have to wait, some researchers have begun to research the possibilities of stem cells in plastic and reconstructive medicine.

“Stem-cell research appears promising for medicine and particularly for plastic surgery,” said Dr. Ronald Friedman, director of the West Plano Plastic Surgery Center and a board-certified plastic surgeon practicing in Plano, Tex.

“Hair follicular stem cells, tooth stem cells and skin stem cells all show therapeutic promise,” said Denis English, editor in chief of the journal Stem Cells and Development and director of cell biology at the Center of Excellence for Aging and Brain Repair at the University of South Florida in Tampa, Fla. “These can restore hair to a bald man, teeth to those in need and skin to scarred patients.”

The use of stem cells to regenerate tissue is believed to hold promise because stem cells can be nudged to develop into specialized cell types. And some researchers have turned an eye toward stem cells for this very purpose.

In October, a University of Pittsburgh team led by Dr. Peter Rubin received a three-year grant from the National Cancer Institute to explore the possibility of using stem cells derived from a patient’s own fat. Rubin, assistant professor of plastic surgery and co-director of the university’s Adipose Stem Cell Center, used those stem cells to create a durable, shaped piece of replacement tissue.

The research may one day allow breast cancer survivors to take advantage of a natural replacement after a mastectomy.

But with these possible applications in reconstruction, could cosmetic applications be far behind?

“Naturally, the public shows more interest in applications like breast augmentation,” said Dr. Peter Constantino, director of the Center for Facial Reconstruction and Restoration at Roosevelt Hospital in New York.

“In our society, there is such a huge demand for these rejuvenation surgeries, despite their significant risks, that the pragmatist in me cannot deny the likelihood that it will not be long before someone offers a two-stage procedure starting with liposuction followed by injection of these autologous stem cells for breast augmentation or into the face to rejuvenate,” said Dr. Daniel Salomon of the department of molecular and experimental medicine at the Scripps Research Institute in La Jolla, Calif.

Real-World Applications Still Far Off
Though initial research into the potential of stem cells in reconstructive surgery is promising, actual applications    particularly those of a purely cosmetic nature    are still distant.

“This is still very far in the future, except for tabloid speculation,” said Dr. Garry Brody, professor emeritus of plastic and reconstructive surgery at the University of Southern California’s Keck School of Medicine in Los Angeles. “By the time it becomes practical    and affordable    I suspect it will be beyond our lifetimes.”

“Stem cells do have the potential to revolutionize things, but it is not “just around the corner,'” said Constantino. “You can’t just inject ‘fat’ stem cells into a breast and just assume that it’s going to make a nice-looking breast. You could just end up with something fairly lumpy and unappealing.”

The cosmetic applications of stem cells are “25 to 30 years away, at the earliest,” said Thoru Pederson of the department of biochemistry and molecular biology at the University of Massachusetts Medical School in Worcester, Mass.

Yet some studies are already under way.
“We are starting to see clinical trials with stem cells for reconstructive surgery,” Rubin said. “A group from Japan reported on enriching liposuctioned fat with fat-derived stem cells and using the material successfully for breast enlargement.”

Cosmetic Uses of Stem Cells a Low Priority
Most experts agree, however, that many other potentially curative and life-saving applications of stem cells take precedence over cosmetic uses.

“Applications to rejuvenation or enhanced personal appearance are much harder to justify at this point and will be driven more by market forces in affluent countries   not just the U.S. certainly    rather than by science,” Salomon said.

“In my opinion, use of any cells for cosmetic surgery is still problematic,” said Dr. Darwin Prockop, director of the Center for Gene Therapy at Tulane University Health Sciences Center in New Orleans. “The trials that can be justified are in patients with terminal diseases in which the potential risks and benefits are carefully evaluated.”

“In all honesty, the more promising (and more quickly realized) aspects of stem cell use in plastic and reconstructive surgery will probably be in producing skin replacement grafts on a large scale,” Constantino said. “This could help many, many burn and chronic wound patients.”

But for now?
“Though there is an enormous amount of promise with stem cells in plastic and reconstructive surgery, the devil is in some pretty important details,” Constantino said.

Source:ABC News.