The relationship between chronic ethanol exposure and cigarette smoking in the laboratory and the natural environment

Few studies have examined the association between ethanol use and cigarette smoking topography. In particular, no study has objectively investigated the relationship between chronic ethanol exposure and cigarette smoking. The aim of this study was to quantify the relationship between cigarette smoking and past and current ethanol use. Male and female cigarette smokers (n=77) between the ages of 30 and 65 years were recruited and grouped as a function of their past and current ethanol use. Group 1 (n=18) included subjects who were ethanol abstinent for the 3 months prior to the study and had no history of alcohol abuse (as defined by DSM-III criteria). Group 2 (n=19) included subjects who were current regular ethanol users and had no history of alcohol abuse. Group 3 (n=20) included subjects who were ethanol abstinent and had a history of alcohol abuse. Group 4 (n=20) included current regular ethanol users with a history of alcohol abuse. A history of alcohol abuse was associated with an intensified pattern of cigarette smoking. Significant differences were observed for total daily smoke exposure, cigarette number, puff number, total puff and inhalation volume, and the nicotine, tar and carbon monoxide yields of the cigarettes smoked. Increased expired-air carbon monoxide and serum cotinine levels were also observed. Current ethanol use was not associated with an increased cigarette smoking pattern. These data suggest that alcohol abusers are at greater risk of contracting cigarette-related pathology.Supported by National Institute on Drug Abuse Research Grant No. DA 05013 and DA 02988     

Differential effects of two visual cortical lesions in the rabbit

Acquisition and retention of brightness and pattern discrimination in rabbits with lesions of visual cortical areas Visual I or I + II was investigated. Rabbits with such lesions did not differ from normals in learning a brightness discrimination but those with Visual I + II lesions showed an impairment in retention of a preoperatively learned brightness discrimination. Rabbits with Visual I lesions were significantly impaired in acquisition of a pattern discrimination and rabbits with both lesions showed even more severe impairment on this task. The role of posterior thalamic nuclei and extrastriate cortex in visual discrimination is discussed.     

Left ventricular systolic and diastolic function in hyperthyroidism

In order to assess the effect of hyperthyroidism on systolic and diastolic function of the left ventricle, M-mode echocardiograms and systolic time intervals were obtained in 13 patients while they were clinically hyperthyroid and again when they were euthyroid following radioactive lodine therapy. Echocardiographic tracings of the septum and left ventricular posterior wall were digitized and analyzed to provide the maximum velocity of shortening and maximum velocity of lengthening. These velocities were normalized for left ventricular diastolic dimension. The left ventricular minor axis fractional shortening and the normalized maximum velocity of shortening were both increased during the hyperthyroid state. The normalized maximum velocity of lengthening, a measure of diastolic left ventricular function, was also increased during the hyperthyroid state when compared to the euthyroid state. The preejection period index and the preejection period/left ventricular ejection time ratio were lower when the patients were hyperthyroid than when they were euthyroid. These data confirm the increased inotropic state and demonstrated increased diastolic relaxation velocities of the hyperthyroid left ventricle.     

Distribution of GABAA and GABAB receptors in mammalian brain: Potential targets for drug development

GABA is the major inhibitory neurotransmitter in mammalian brain. GABA receptors and the metabolism of GABA are significant targets for new centrally acting drugs to treat neurological and behavioral disorders. The simple neutral amino acid is likely to subserve a neurotransmitter role at 25–50% of all synapses in the central nervous system. GABA's actions are mediated by two different receptors, GABA_A and GABA_B receptors. GABA_A receptors are ligand-gated chloride channels that are sensitive to the convulsant alkaloid bicuculline and modulated by benzodiazepines and barbiturates. GABA_B receptors affect calcium and potassium conductance through GTP binding proteins and are insensitive to bicuculline and sensitive to the agonist baclofen. Both receptors are widely distributed in cerebral cortex, hippocampus, basal ganglia, thalamus, cerebellum, and brainstem.