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Biomedical subjects

L Lake

Publications and source records attributed to L Lake.

5 recordsLinked to original sources

Restrained eating: measuring an elusive construct.

As a measure of restrained eating, Herman's Restraint Scale (1978) reliably predicts laboratory food consumption in college students regardless of their weight. However, the generality and psychometric properties of the scale have not been established. In the present study, 136 male and female adults were cross-classified as obese and normal and as dieting or non-dieting. The subjects were administered a single questionnaire containing items of the Lie, Social Desirability, and Restraint scales presented in randomized order. Unlike previous reports by Herman, the three adult groups differed significantly on the Restraint Scale in the following order: Obese dieters greater than Obese non-dieters greater than normals. Also, alpha reliability coefficients varied across groups and corrected item-total correlations also displayed considerable variability with no uniformity apparent for individual item correlations. The factor analysis identified three factors within the ten item scale, and for the obese dieters, the scale was not independent of social desirability. These results indicate that the Restraint Scale has limited usefulness beyond laboratory settings with college students.

Adolescent

Cellular and molecular toxicology of lead. II. Effect of lead on delta-aminolevulinic acid synthetase of cultured cells.

The effect of lead nitrate on delta-aminolevulinic acid synthetase (ALA synthetase), the first and rate-limiting enzyme of the heme biosynthetic pathway, was studied by using an established rat liver cell line (RLC-GAI). Lead was shown to produce a time-dependent increase in ALA synthetase activity, with a maximum after incubation of the cells for 24 h with 10(-5) M lead nitrate. The effect of lead was not liver-specific in that increases in enzyme activity were produced in other tissue-derived cell lines. Cycloheximide but not actinomycin D, cordycepin, or hydroxyurea, at concentrations that inhibit the synthesis of protein, RNA, and DNA, prevented the lead-associated increase in ALA synthetase activity. Heme, added to the cells as hemin, also prevented the effect of lead. These results indicate that lead induced the synthesis of ALA synthetase secondary to an inhibition of the synthesis of heme.

5-Aminolevulinate Synthetase

Cellular and molecular toxicology of lead. III Effect of lead on heme synthesis.

The effect of lead nitrate on the biosynthesis of heme and the cellular uptake of (59)Fe was studied in an established rat liver cell line (RLC-GAI) grown in serum-free medium. Heme synthesis was shown to be increased in lead-treated cells when determined by measuring the amount of (59)Fe incorporated into the heme fraction of cell homogenates; concomitant with increased (59)Fe incorporation into heme, cellular uptake of (59)Fe was also increased. By contrast, heme synthesis was inhibited by lead in a dose-dependent manner when determined by measuring the conversion of ((14)C) aminolevulinic acid into heme under identical experimental conditions. Cellular degradation of heme was not found to be significantly affected by lead. It is proposed that lead inhibited the biosynthesis of heme and that the increased incorporation of (59)Fe into the heme fraction of the lead-treated cells was the result of the increased uptake of (59)Fe and hence labeling of the heme molecules. Evidence is presented that suggests that only (59)Fe present in solution as a low-molecular-weight complex was accumulated in increased amounts by lead-treated cells.

Animals

Early shift in A&E.

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Emergency Nursing