Daily self-weighing compared with an active control causes greater negative affective lability in emerging adult women: A randomized trial

Age-related weight gain prevention may reduce population overweight/obesity. Emerging adulthood is a crucial time to act, as rate of gain accelerates and health habits develop. Evidence supports self-weighing (SW) for preventing weight gain; however, how SW impacts psychological states and behaviors in vulnerable groups is unclear. This study assessed daily SW effects on affective lability, stress, weight-related stress, body satisfaction, and weight-control behaviors. Sixty-nine university females (aged 18-22) were randomized to daily SW or temperature-taking (TT) control. Over 2 weeks, participants completed five daily ecological momentary assessments with their intervention behavior. A graph of their data with a trendline was emailed daily, with no other intervention components. Multilevel mixed models with random effect for day assessed variability in positive/negative affect. Generalized linear mixed models assessed outcomes pre- and post-SW or TT and generalized estimating equations assessed weight-control behaviors. Negative affective lability was significantly greater for SW versus TT. While general stress did not differ between groups, weight-related stress was significantly higher and body satisfaction was significantly lower post-behavior for SW but not TT. Groups did not significantly differ in the number or probability of weight-control behaviors. Caution is advised when recommending self-weighing to prevent weight gain for emerging adults.

The susceptibility of membrane vesicles to interaction with ethanol

The susceptibility of membranes to interaction with ethanol is an important consideration in the further understanding of the ethanol-membrane interaction. Interaction of membrane vesicles, including passive diffusion of ethanol across membranes, leakage of internal molecules out of membranes and membrane-membrane interaction, were examined systematically using two populations of fluorescent probe-encapsulated phospholipid bilayer vesicles, each prepared with 1,2-dimyristoyl phosphatidylcholine, cholesterol and a fluorescent probe. Fluorescence quenching experiments with these vesicles were performed in a medium containing a wide range of ethanol concentrations (0.30-3.5 M). In the presence of a lower concentration of ethanol in the external medium, passive diffusion of ethanol across membrane vesicles occurred. This was demonstrated by an interaction of ethanol with the encapsulated fluorescence probe molecules inside the vesicles, resulting in an increase in the fluorescence intensity and a shift of the fluorescence emission spectrum to a shorter wavelength. While, in the presence of a higher concentration of ethanol in the external medium, a strong perturbation of lipid bilayers by ethanol was found, leading to an over expansion of membranes and consequently causing the membrane leakage. As a result of this, the initially encapsulated probe molecules leaked out of the vesicles so as to interact with the other probe molecules in the external medium. Consequently, fluorescence quenching was observed. Moreover, studies of the mixture of two populations of fluorescence probe-encapsulated membrane vesicles revealed that ethanol acted on individual membranes and did not promote membrane-membrane interactions. The implication of the present results to the alcohol-mediated expansion of membranes is discussed.

Effect of aging on gentamicin nephrotoxicity and pharmacokinetics in rats

In humans a higher incidence of renal toxicity is seen in old than in young patients undergoing gentamicin therapy. To investigate whether the sensitivity of the old kidney to gentamicin is a function of age, separate from the adverse effects arising from declining renal excretory function, the nephrotoxicity of 12 daily injections of this antibiotic was measured in rats. Young (7-10 months) and old (25-28 months) rats, selected for minimal age-related nephropathy, received an initial dose of 30 or 50 mg of gentamycin/kg. Based on the plasma half-lives, subsequent doses for the high dose group were reduced as needed to equalize renal exposure to gentamicin. Urinary excretion of beta-galactosidase peaked by the second or third day of injections, while proteinuria was highest in the second week. The amount of microscopic renal tubular damage was dose-related and was greater in the old rats of each dose group. The increased sensitivity of old kidneys toward gentamycin toxicity, although small, thus appears to be in addition to any age-related decrease in renal elimination of the drug from plasma.