Advances in alcohol & substance abuse最新文献

Imaging in vivo aspects of brain structure and function hold great promise for the study of alcoholism. Computerized axial tomography and magnetic resonance imaging have been used successfully to demonstrate structural abnormalities in alcoholic patients. Positron emission tomography and topographic images of electrical and magnetic activity are useful measures of brain function that could be applied more rigorously to the study of alcoholism. Interrelating various types of imaging data is an important area that is still in the developmental stage.

Using protein and enzymatic methods, a major role in ethanol metabolism was assigned to the alcohol dehydrogenase (ADH) enzymes. Three major classes of ADHs were described on the basis of structure and function, including timing and location of expression. Polymorphic variants, including a common functional variant, were identified. Molecular cloning allowed the demonstration of a high degree of sequence homology between the three class I ADH genes and enabled the definition of ADH variants at the DNA sequence level. The existence of an ADH gene cluster on chromosome 4 and the shared evolutionary roots of these genes suggests that the continued integration of studies of the different ADH genes will yield further insights into alcohol metabolism in humans.

The aim of this study was to develop and characterize a model system in which the effects of ethanol on voltage- and agonist-gated ionic currents in adult mammalian neurons could be studied using voltage-clamp techniques. We have found that neurons enzymatically isolated from the peripheral (nodose and superior cervical ganglia) and central nervous system (pyramidal layer of the hippocampus) of the adult rat and guinea pig provide several advantages over conventional neuronal preparations (e.g., intact ganglia or brain slice). First, the isolated neurons, in conjunction with the patch clamp technique, allow high fidelity recordings of both macroscopic and single channel currents. Secondly, current- and voltage-clamp recordings have revealed that active and passive membrane properties, chemosensitivity, and ionic currents in the isolated neurons resemble those described from conventional preparations. Finally, we have developed an intracellular perfusion system which allows the convenient control of the intracellular milieu. This technique should be useful for the study of intracellular second messengers on ionic currents. Our results demonstrate that isolated adult mammalian neurons are ideally suited for the study of both the acute and chronic effects of ethanol on membrane excitability.

The effort to prevent further HIV infection for high risk populations has been largely limited, in practice, to health education efforts. Prevention policy must utilize techniques which, in combination with health education efforts, works to decrease behaviors which are implicated in HIV transmission. It is argued that this approach to prevention will work best if it is designed with an understanding of the conditions under which individuals decline to comply with risk-reduction guidelines. It appears that the use of drugs and alcohol during sexual contact is one such condition. Three prevention strategies are suggested which, in addition to health education efforts, might be used to minimize HIV transmission related to the use of drugs and alcohol during sexual activity among gay men. It is hoped that the approach suggested in this paper for the prevention of further HIV infection might also be adopted to develop prevention strategies for other populations at risk of HIV infection.

We investigated the possibility that organs other than liver in women were more susceptible to alcohol than in men. Female:male cirrhosis mortality ratio in different countries was used as an index of female susceptibility to alcohol. The F:M cirrhosis ratio correlated significantly with F:M ratios for cerebrovascular disease and cancers of the esophagus, liver and lung. This preliminary evidence suggests that other organs and/or disease processes in women may be affected more by alcohol than in men.

Marijuana is reported to decrease spasticity in patients with multiple sclerosis. This is a double blind, placebo controlled, crossover clinical trial of delta-9-THC in 13 subjects with clinical multiple sclerosis and spasticity. Subjects received escalating doses of THC in the range of 2.5-15 mg., five days of THC and five days of placebo in randomized order, divided by a two-day washout period. Subjective ratings of spasticity and side effects were completed and semiquantitative neurological examinations were performed. At doses greater than 7.5 mg there was significant improvement in patient ratings of spasticity compared to placebo. These positive findings in a treatment failure population suggest a role for THC in the treatment of spasticity in multiple sclerosis.

An association between alcohol consumption, blood pressure levels and the prevalence of hypertension has been described in close to twenty population studies. The relationship is independent of ethnic group, gender, type of alcohol, cigarette smoking and obesity, but additive to effects of obesity and oral contraceptive use. Several studies show a progressive rise in blood pressure throughout the entire range of alcohol consumption. Reports indicating a threshold for the effect at around 30 g ethanol per day (three standard drinks) may be artefactual due to underreporting of drinking levels. Drinkers consuming an average of 3 or more glasses per day have three to four times the prevalence of "hypertension" compared with teetotallers. A randomized, controlled trial of moderating alcohol consumption in normotensives has confirmed a direct pressor action of alcohol and is supported by studies in hypertensives. These observations have important implications for the prevention and management of essential hypertension in most communities.