Ion filtration chromatography: a powerful new technique for enzyme purification applied to E. coli alkaline phosphatase.
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Alkaline Phosphatase↗
Biomedical subjects
T J Johnson
Publications and source records attributed to T J Johnson.
Social anxiety, alcohol expectancies, and drinking-game participation.
Few studies have investigated factors contributing to college student participation in drinking games. The extent to which drinking games contribute to negative alcohol-related consequences is uncertain. The current study attempted to (a) clarify the risks posed by drinking-game participation, (b) identify characteristics of heavy drinkers who play frequently and those who seldom play, and (c) determine if students participated in drinking games to reduce anxiety in social situations. Tension reduction alcohol expectancies were examined as a potential moderator variable for the relationship between social anxiety and frequency of play. Drinking games accounted for high proportions of all negative alcohol-related consequences and appeared to be strongly associated with instances of sexual victimization. Contrary to predictions based on the tension reduction hypothesis, greater frequency of play was associated with lower social anxiety, and no moderating effect was found for tension reduction expectancies. Frequent players also had more environmental exposure to drinking games. In men, heavy-drinking players may resemble Clonninger's Type 1 alcoholic, whereas heavy-drinking nonplayers resemble the Type 2 pattern. A full understanding of college student drinking behavior may not be possible without greater understanding of drinking games.
Adult↗
College students' self-reported reasons for playing drinking games.
Two samples of college students who engage in drinking games completed questions about their drinking behavior, a set of items concerning their reasons for playing drinking games, and various self-report measures of personality. Principal components analysis using the first sample yielded four factors: Relaxation & Disinhibition, Fun & Celebration, Conformity, and Sexual Manipulation. A similar factor structure was also obtained in the second sample. In both samples, Fun & Celebration and Sexual Manipulation reasons were most strongly predictive of frequency of play and quantity of alcohol consumed while playing. In men, Sexual Manipulation reasons for play predicted frequency of taking sexual advantage of others during play. Endorsement of Conformity and Relaxation & Disinhibition reasons were associated with high social anxiety and low assertiveness. Reasons for play predicted consumption, both in drinking-game situations and overall, even after removing variance due to general reasons for drinking. Psychometric properties of the current measure are less than ideal, but the constructs identified appear to have important implications for prevention. Assessment of self-reported reasons for drinking in specific situations may be a generally useful strategy.
Adolescent↗
Sensation seeking and drinking game participation in heavy-drinking college students.
Previous research has identified differences between heavy-drinking students who play drinking games and those who do not. Johnson, Wendel, and Hamilton (1998) suggested that heavy-drinking players may correspond to Cloninger's (1987) Type II alcoholic and that heavy-drinking nonplayers resemble Type I. The current study predicted that (a) sensation seeking would be associated with greater frequency of play and greater frequency of negative consequences from play and that (b) heavy-drinking students who play drinking games would be higher in sensation seeking than heavy-drinking students who do not play. A sample of 172 female and 84 male college students completed the Sensation Seeking Scale Form V, questions about quantity and frequency of alcohol consumption, and questions regarding drinking game participation. Higher levels of sensation seeking predicted greater frequency of play even after controlling for overall quantity and frequency of consumption. Sensation seeking was also related to specific motives for play. Men who were higher in sensation seeking experienced more negative alcohol-related consequences as a result of play. In women, but not in men. heavy-drinking players were higher in sensation seeking than heavy-nondrinking nonplayers. The results of the current study do not clearly support Cloninger's model, but they are consistent with other research concerning the role of sensation seeking and risk taking in contributing to negative alcohol-related consequences. Personality style likely interacts with social norms and contextual factors in influencing drinking game participation and consequences of play.
Adolescent↗
Effects of portal vein stenosis and superior mesenteric vein ligation on mesenteric venous pressure and porta-systemic shunting in the rat.
We studied the relative contributions of splanchnic congestion and porta-systemic shunting to the maintenance of experimental portal venous hypertension. Three groups of rats were prepared: portal vein-stenosed, superior mesenteric vein-ligated and sham operated. Though elevated in both operated groups compared to controls, mesenteric venous pressure was highest in the portal vein-stenosed animals (PV vs SMV vs Sham: 19.6 +/- 1.3 vs 15.6 +/- 0.7 vs 13 +/- 0.6; p < .05 PV and SMV vs Sham, and PV vs SMV) despite the presence of 50% porta-systemic shunting in the portal vein-stenosed animals. Shunting was negligible in the other two groups. Peripheral plasma glucagon and vasoactive intestinal peptide (VIP) levels were similar in all three groups. We conclude that mesenteric congestion alone plays a minor role in the pathogenesis of portal hypertension, which may instead be related to the porta-systemic shunting of vasoactive substances other than glucagon and VIP.
Animals↗
The short-term effect of low concentrations of dietary aflatoxin and T-2 toxin on mallard ducklings.
Two 9-day trials to study effects of dietary mycotoxins were conducted using 6-week-old mallards. Each trial involved three groups of six ducks each, three males and three females per group. One group was fed no myocotoxin (control), one was fed aflatoxin, and the third was fed T-2 toxin. Dietary aflatoxin was 12 ppb in trial 1 and 33 ppb in trial 2; dietary T-2 toxin was 2 ppm in both trials. There were no gross or microscopic lesions in controls or in ducks fed aflatoxin, nor did these groups differ significantly in final body weight or in weights of spleen or bursa of Fabricius. Ducks exposed to T-2 toxin had erosions and/or ulcerations in the oral cavity and esophagus; further, these ducks exhibited a decrease in weights of body, thymus, spleen, and bursa of Fabricius. The only microscopic change seen in lymphoid organs of ducks exposed to T-2 toxin was a moderate decrease of thymic cortical lymphocytes.
Aflatoxins↗