Demographic and risk factors associated with chronic dieting in adolescents

A comprehensive, school-based survey was administered to 36,320 Minnesota public school students in grades 7 through 12 during the 1987-1988 school year. Self-reported chronic dieting was much higher in girls than in boys (12.1% of all girls vs 2.1% of boys). For girls, the percentage of chronic dieters was significantly less in grades 7 and 8 (7.8%) than in grades 9 and 10 (13.5%) or grades 11 and 12 (14.3%). There were no differences among urban, suburban, or rural youth. Black girls were less likely to diet compared with white girls. Chronic dieters were more likely than other students to report maladaptive weight-loss techniques, such as self-induced vomiting (relative risk, 9.92 for girls and 9.40 for boys), laxative use (relative risk, 7.18 for girls and 11.00 for boys), ipecac use (relative risk, 8.33 for girls and 11.00 for boys), and diuretic use (relative risk, 7.30 for girls and 13.5 for boys). It is suggested that chronic dieting may serve as a screening marker for more severe eating and weight-loss behaviors.     

Patterns of health-compromising behaviors among Minnesota adolescents: sociodemographic variations.

OBJECTIVES: This study compared prevalence rates of health-compromising behaviors among boys and girls from different ethnic backgrounds in early, middle, and late adolescence and compared co-occurrences of such behaviors across gender and ethnic groups. METHODS: The study population included 123 132 adolescents in grades 6, 9, and 12. Adolescents completed a classroom-administered statewide survey focusing on high-risk behaviors, including unhealthy weight loss, substance abuse, suicide risk, delinquency, and sexual activity. RESULTS: Prevalence rates of most health-compromising behaviors differed by gender, increased with age, and tended to be highest among American Indian youth and lowest among Asian Americans. Strong associations were found between substance abuse and delinquency across all ethnic groups. Substance abuse and delinquency were associated with suicide risk across most ethnic groups. Covariations with sexual activity and unhealthy weight loss behaviors showed more ethnic variation. CONCLUSIONS: Prevention interventions should take into account the tendency for health-compromising behaviors to co-occur and should be sensitive to demographic and socioeconomic differences in behavior patterns.     

Involvement of Ca+ mobilization in the amplifying effect of serotonin on responses of rabbit isolated ear artery to exogenous noradrenaline

Summary The present study examined the involvement of Ca⁺ mobilization in the amplifying effect of serotonin on steady-state responses of rabbit isolated perfused ear artery to exogenous noradrenaline (NA; 0.001–3 ol/l). In contrast to its marked amplifying effect on responses to NA, serotonin in the subconstrictor concentration of 100 nmol/l had no effect on responses to KCl. The Ca⁺-entry blocking drug diltiazem (10 gmol/1) decreased responses to NA; in addition, the amplifying effect of serotonin on responses to NA was reduced by diltiazem. Lowering the concentration of Ca⁺ in the Krebs-Henseleit perfusion solution from 2.5 to 0.25 mmol/l also reduced both responses to NA and the amplifying effect of serotonin. Using the method of Manzini et al. (1982), separate intra- and extracellular Ca⁺-dependent responses to NA were obtained. Serotonin had no effect on intracellular Ca⁺-dependent responses to NA but enhanced extracellular Ca²⁺-dependent NA responses. These results suggest that the amplifying effect of serotonin on responses of rabbit ear artery to exogenous NA involves a selective enhancement of the component of the NA response which is dependent on extracellular Ca⁺; serotonin may increase NA-evoked entry of Ca²⁺ into the vascular smooth muscle cells through receptor-operated Ca⁺ channels. Send offprint requests to A. G. Meehan at the above address     

Autonomic control of acid phosphatase exocrine secretion by the rat prostate

Summary In vivo prostatic secretion was collected from retired breeder Sprague Dawley rats using a method for isolated perfusion of the rat prostatic urethra. Enzymatic acid phosphatase determination was performed on the collected effluent. Control acid phosphatase secretion was 24.2±2.7 nm over 30 minutes. Intravenous phenylephrine 5 mg/kg stimulated a 10 fold increase in acid phosphatase secretion. The secretion seen with phenylephrine was dose dependent and could be blocked with prazosin, but not yohimbine, atropine, or propranolol. Intravenous -adrenergic agonist isoproterenol caused no increase in the secretion of rat prostatic acid phosphatese. Intravenous administration of the cholinergic agonist pilocarpine also resulted in a dose dependent rise in acid phosphatase secretion. The stimulation seen could be blocked by atropine but not phentolamine or propranolol. The stimulation of acid phosphatase secretion seen with ₁ adrenergic or cholinergic agonists was not additive. Intravenous vasoactive intestinal peptide did not stimulate acid phosphatase secretion nor did it augment the secretion induced by ₁ adrenergic or cholinergic agonists. Release of acid phosphatase into rat prostatic exocrine secretion is under both ₁ adrenergic and cholinergic control.Supported by the US Veterans Administration     

The effect of PVC packaging on the acidity of 0.9% saline

Intravenous fluids in polyvinyl chloride (PVC) packaging are known to be acidic. We proposed to determine the effect of PVC packaging on the pH of 0.9% saline solutions by comparing the predicted and measured pH of 0.9% saline equilibrated with atmospheric carbon dioxide and the measured pH of commercial solutions of 0.9% saline in PVC and polypropylene packaging. Calculation of pH was made from available physical chemistry constants and data. Measurement was made of the pH of 12 samples of prepared 0.9% saline equilibrated with atmospheric carbon dioxide. Comparison with the pH of seven commercial samples of saline in PVC packaging for intravenous use was undertaken. Further comparison was made between commercial samples of 0.9% saline in PVC or polypropylene packaging. The calculated pH of 0.9% saline was 5.61 at 20 degrees C. The median pH of the prepared samples was statistically significantly less acidic than the median pH of the PVC packaged samples for intravenous use: 5.47 vs 4.60, P < 0.05. The median pH of the PVC packaged saline was also statistically significantly more acidic than the pH of the polypropylene packaged saline: 4.62 vs 5.71, P < 0.05. The acidity of the intravenous solutions of 0.9% saline packaged in PVC was much greater than expected and is only partially explained by dissolved carbon dioxide. This acidity could be a result of packaging in PVC.