Posts tagged alcohol

Chronic alcohol abuse can severely damage the nervous system, particularly cognitive functions, cerebral metabolism, and brain morphology. Building upon previous findings that alcoholics can experience brain volume recovery with abstinence, this study found that recovery of cerebral gray matter (GM) can take place within the first two weeks of abstinence, but may vary between brain regions.

Results will be published in the January 2013 issue of Alcoholism: Clinical & Experimental Research and are currently available at Early View.

"Shrinkage of brain matter, and an accompanying increase of cerebrospinal fluid, which acts as a cushion or buffer for the brain, are well-known degradations caused by alcohol abuse," explained Gabriele Ende, professor of medical physics in the Department of Neuroimaging at the Central Institute of Mental Health. 
 "This volume loss has previously been associated with neuropsychological deficits such as memory loss, concentration deficits, and increased impulsivity."

"Several processes likely account for changes in brain tissue volume observed through bouts of drinking and abstinence over the course of alcoholism," added Natalie May Zahr, a research scientist in the Department of Psychiatry and Behavioral Sciences at Stanford University School of Medicine. "One process likely reflects true, irreversible neuronal cell death, while another process likely reflects shrinkage, a mechanism that would allow for volume changes in both negative and positive directions, and could account for brain volume recovery with abstinence."

"Gray matter (GM) and white matter (WM) are the main components of the brain that can be distinguished with magnetic resonance imaging (MRI)," explained Ende. "GM consists of neuronal cell bodies, neuropil, glial cells, and capillaries. WM mostly contains myelinated axon tracts."

"Myelin forms an insulating sheath around axons that increases the speed at which they are able to conduct electrical activity," added Zahr. "Because myelin is composed primarily of fat, it gives white matter its color. Cerebrospinal fluid (CSF) is a clear fluid that surrounds and thereby cushions the brain in the skull. Conventional brain structural MRI produces images of protons, with contributions primarily from water and some from fat. Tissue contrast is possible because of the fundamental differences in water content in the primary tissues of the brain: WM consists of about 70 percent water, GM 80 percent, and CSF 99 percent."

(Source: eurekalert.org)

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A collaborative research effort by scientists at the University of North Carolina School of Medicine, Duke University, and University College of London in the UK, sheds new light on alcohol-related birth defects.

The project, led by Kathleen K. Sulik, PhD, a professor in the Department of Cell and Developmental Biology and the Bowles Center for Alcohol Studies at UNC, could help enhance how doctors diagnose birth defects caused by alcohol exposure in the womb. The findings also illustrate how the precise timing of that exposure could determine the specific kinds of defects.

“We now know that maternal alcohol use is the leading known and preventable cause of birth defects and mental disability in the United States,” Sulik said. “Alcohol’s effects can cause a range of cognitive, developmental and behavioral problems that typically become evident during childhood, and last a lifetime.”

Fetal alcohol syndrome (FAS) is at the severe end of fetal alcohol spectrum disorders (FASD). First described in 1972, FAS is recognized by a specific pattern of facial features: small eyelid openings, a smooth ridge on the upper lip (absence of a central groove, or philtrum), and a thin upper lip border.

In its full-blown state, FAS affects roughly 1 in 750 live births in the U.S. And while clinicians typically look for those classical facial features in making a diagnosis, within the broader classification of FASD “adverse outcomes vary considerably and most individuals don’t exhibit the facial characteristics that currently define FAS,” said the study’s lead author Robert J. Lipinski, PhD, a postdoctoral scientist in Sulik’s lab. “This study could expand the base of diagnostic criteria used by clinicians who suspect problems caused by maternal alcohol use.”

In their animal-based studies, the Sulik lab team has collaborated with co-author G. Allan Johnson, PhD and his group at Duke University’s Center for In Vivo Microscopy. Johnson, professor of radiology and physics, has developed new imaging tools with spatial resolution up to a million times higher than clinical magnetic resonance imaging (MRI). These include small bore tools suitable for imaging fetal mice that are only 15 mm long.

To quantify facial shape from MRI data, the study team turned to co-author Peter Hammond, a professor of computational biology at UCL’s Institute of Child Health, in London. Hammond invented powerful new techniques for 3D shape analysis that have already proven successful in objectively defining facial shape changes in humans.

In the study, described in the August 22, 2012 issue of the online journal PLOS ONE, Lipinski and Sulik treated one group of mice with alcohol on their seventh day of pregnancy, a time corresponding to the third week of pregnancy in humans. A second group of mice was treated just 36 hours later, approximating the fourth week of human pregnancy. The amount of alcohol given was large, “high doses that most women wouldn’t achieve unless they were alcoholic and had a tolerance for alcohol,” Sulik said.

Near the end of pregnancy, the fetuses were then imaged at Duke University. These 3D data sets showed individual brain regions, as well as accurate and detailed facial surfaces, from which Hammond and research assistant and co-author Michael Suttie performed shape analyses.

The team found that the earlier alcohol exposure time elicited the classic FAS facial features, including characteristic abnormalities of the upper lip and eyes. What they observed in fetuses exposed just 36 hours later, however, was a surprise. These mice exhibited unique and in some cases opposing facial patterns, such as shortened upper lip, a present philtrum, and the brain, instead of appearing too narrow in the front, appeared wide.

“Overall, the results of our studies show that alcohol can cause more than one pattern of birth defects, and that the type and extent of brain abnormalities—which are the most devastating manifestation of prenatal alcohol exposure—in some cases may be predicted by specific facial features,” Sulik said. “And, importantly, alcohol can cause tremendously devastating and permanent damage at a time in development when most women don’t recognize that they’re pregnant.”

Source: Newswise

ScienceDaily (June 13, 2012) — Research into alcohol’s effect on juvenile rats shows they have an ability to build up a physical, but not cognitive, tolerance over the short term — a finding that could have implications for adolescent humans, according to Baylor University psychologists.

The research findings are significant because they indicate that blood alcohol concentration levels alone may not fully account for impaired orientation and navigation ability, said Jim Diaz-Granados, Ph.D., professor and chair of psychology and neuroscience at Baylor. He co-authored the study, published in the journal Brain Research.  “There’s been a lot of supposition about the reaction to blood alcohol levels,” Diaz-Granados said. “We use the blood alcohol level to decide if someone is going to get arrested, because we think that a high level means impairment. But here we see a model where we can separate that out. You may have a tolerance in metabolism, but just because your blood alcohol concentration is less than the legal limit doesn’t mean your behavior isn’t impaired.”

"More research is needed to fully understand how adolescents react to alcohol, but this contributes a piece to the puzzle," said study co-author Douglas Matthews, Ph.D., a research scientist at Baylor and an associate professor in Psychology at Nanyang Technological University in Singapore.

The study was conducted in the Baylor Addiction Research Center of Baylor’s Department of Psychology and Neuroscience in Baylor’s College of Arts & Sciences.

More than half of under-age alcohol use is due to binge drinking, according to the Substance Abuse and Mental Health Services Administration, and “when initial alcohol use occurs during adolescence, it increases the chance of developing alcoholism later in life,” said lead study author Candice E. Van Skike, a doctoral candidate in psychology at Baylor. Researchers have long been interested in whether adolescents react differently to alcohol than adults and how alcohol use affects their brains when they reach adulthood, but Baylor researchers also wanted to test the short-term effect of alcohol on adolescents’ brains in terms of memory about space and dimension.

In the study, 96 rats were trained to navigate a water maze to an escape platform. Half were exposed to alcohol vapor in chambers for 16 hours a day over four days (a method to approximate binge-like alcohol intake), while others were exposed only to air. After a 28-hour break, some were injected with alcohol, then both groups tested again in the maze. A comparison found that those who had undergone the chronic intermittent ethanol exposure built up a metabolic tolerance. They were better able to eliminate alcohol from their systems than ones who had been exposed only to air, based on a comparison of the blood ethanol concentrations of the two groups after they had been injected with alcohol later. While the alcohol-injected rats swam as hard and as fast as the others, their ability to find the escape platform was impaired.

Previous research at Baylor led by Matthews showed that adolescents are less sensitive than adults to motor impairment during alcohol intake because a particular neuron fires more slowly in adults who are drinking. The lack of sensitivity may be part of the reason adolescents do not realize they have had too much to drink.

"It’s difficult to compare metabolic and cognitive tolerance in adults with those of juveniles, because many studies that have looked at the cognitive aspect of chronic ethanol exposure didn’t measure blood alcohol concentration levels," Van Skike said. "It would be an interesting comparison to make, and it is an avenue for future research."

Other research has shown that high levels of alcohol consumption during human adolescence are mirrored in animals. Adolescent rats consume two to three times more ethanol than adults relative to body weight, suggesting that adolescents are who drink are pre-disposed to do so in binges.

Source: Science Daily

ScienceDaily (June 6, 2012) — Cutting the amount we drink to just over half a unit a day could save 4,600 lives a year in England, according to a modelling study by Oxford University researchers published in the journal BMJ Open.

Half a unit of alcohol is as little as a quarter of a glass of wine, or a quarter of a pint. (Credit: © G.G. Lattek / Fotolia)

Scientists have carried out a complex analysis in an attempt to determine the “optimal” level of alcohol consumption that is associated with the lowest rates of chronic disease in the UK. They conclude that the intake of about one-half of a typical drink per day would result in the healthiest outcomes, and the authors conclude that the recommended alcohol intake for the UK should be reduced from the current advised level of drinking.

Half a unit of alcohol is as little as a quarter of a glass of wine, or a quarter of a pint. That’s much lower than current government recommendations of between 3 to 4 units a day for men and 2-3 units for women.

The researchers set out to find the optimum daily amount of alcohol that would see fewest deaths across England from a whole range of diseases connected to drink. Previous studies have often looked at the separate effects of alcohol on heart disease, liver disease or cancers in isolation.

'Although there is good evidence that moderate alcohol consumption protects against heart disease, when all of the chronic disease risks are balanced against each other, the optimal consumption level is much lower than many people believe,' says lead author Dr Melanie Nichols of the BHF Health Promotion Research Group in the Department of Public Health at Oxford University.

The team used a mathematical model to assess what impact changing average alcohol consumption would have on deaths from 11 conditions known to be at least partially linked to drink.

These included coronary heart disease, stroke, high blood pressure, diabetes, cirrhosis of the liver, epilepsy, and five cancers. Over 170,000 people in England died from these 11 conditions in 2006, and ill health linked to alcohol is estimated to cost the NHS in England £3.3 billion every year.

The researchers used information from the 2006 General Household Survey on levels of alcohol consumption among adults in England. They combined this with the disease risks for differing levels of alcohol consumption as established in large analyses of published research.

They found that just over half a unit of alcohol a day was the optimal level of consumption among current drinkers.

They calculate this level of drinking would prevent around 4,579 premature deaths, or around 3% of all deaths from the 11 conditions.

The number of deaths from heart disease would increase by 843, but this would be more than offset by around 2,600 fewer cancer deaths and almost 3,000 fewer liver cirrhosis deaths.

'Moderating your alcohol consumption overall, and avoiding heavy-drinking episodes, is one of several things, alongside a healthy diet and regular physical activity, that you can do to reduce your risk of dying early of chronic diseases,' says Dr Nichols.

She adds: ‘We are not telling people what to do, we are just giving them the best balanced information about the different health effects of alcohol consumption, so that they can make an informed decision about how much to drink.

'People who justify their drinking with the idea that it is good for heart disease should also consider how alcohol is increasing their risk of other chronic diseases. A couple of pints or a couple of glasses of wine per day is not a healthy option.'

Although this study in BMJ Open did not look at patterns of drinking, Dr Nichols says: ‘Regardless of your average intake, if you want to have the best possible health, it is also very important to avoid episodes of heavy drinking (“binge drinking”) as there is very clear evidence that this will increase your risks of many diseases, as well as your risk of injuries.’

Source: Science Daily