Biomedical subjects

D Malon

Publications and source records attributed to D Malon.

3 recordsLinked to original sources

PubMed1991

Cholesterol distribution between high-density-lipoprotein subfractions HDL2 and HDL3 determined in serum by discontinuous gradient gel electrophoresis.

We used discontinuous gradients of polyacrylamide gel to determine the high-density-lipoprotein (HDL) subfractions HDL2 and HDL3 of serum lipoproteins. Serum (40 microL) prestained with Sudan Black was electrophoresed in cylindrical tubes over successive layers of 3.5%, 6%, 13%, and 17.5% acrylamide gels in a Tris.glycine buffer (3-4 h, 300 V). Very-low- (VLDL) and low-density lipoprotein (LDL) were retained by the 3.5% and 6% gels. HDL2 was concentrated at the interface between the 13% and 17.5% gels, and HDL3 migrated into the 17.5% gel. The distribution between HDL2 and HDL3 was obtained by densitometric scanning. Application of the respective percentages to HDL cholesterol assayed after phosphotung-state-Mg2+ precipitation of VLDL and LDL gave calculated concentrations of HDL2 and HDL3 cholesterol. The calculated values for HDL2 cholesterol were in excellent agreement with those for HDL2 isolated by ultracentrifugation (r = 0.920 for n = 120 sera; differences nonsignificant by Student's paired t-test). Besides being highly discriminating, the method is rapid, easily performed, and economical.

Cholesterol↗

PubMed1989

Energy expenditure economy induced by decrease in lean body mass in anorexia nervosa.

In anorexia nervosa, the low energy input associated with the classic overactivity during the malnourished state needs a sparing of energy expended at rest and also during physical activity. Therefore, we measured energy expenditure, both at rest and during moderate bicycling exercise (30W, 6 min), in 11 adult anorectic patients (weight 35.15 +/- 4.30 kg, mean +/- s.d.) at the beginning of their treatment and again after a mean weight gain of about 8.4 kg. During the malnourished state, the resting energy expenditure (REE) was lower than that predicted according to Harris and Benedict (P less than 0.001). Although it was significantly increased after weight gain (P less than 0.05), the REE per kg of lean body mass remained unchanged after repletion. The total oxygen consumption related to exercise remained unchanged after refeeding (2114 +/- 487 ml/15 min, basal vs 2168 +/- 394 ml/15 min, repletion) (n.s.). Thus in anorexia nervosa, weight loss and malnutrition did not induce economy either in energy expended at rest per unit of lean body mass nor in the energy expended in moderate cycling activity.

Adolescent↗

PubMed1988

Low high density lipoprotein-2 concentrations in obese male subjects.

In this study we have compared the lipoprotein patterns, in particular HDL subfractions, of 34 obese men to those of 34 normoponderal normolipemic men, matched for age and use of tobacco. Obesity was associated with increased VLDL concentrations in only half the subjects. HDL concentrations in all obese subjects were lower than in matched controls. The decrease was most marked in the HDL2 subfraction in which cholesterol and protein contents were decreased by 50%; it was independent of triglyceride levels and not related to the severity of overweight. Moreover, while HDL2 was negatively correlated with BMI (P less than 0.01) when both populations were considered together, the correlation disappeared when calculated separately within each population, suggesting a threshold effect. The low levels of HDL2 might result from discretely altered lipolysis, not sufficient to cause an elevation in fasting triglyceridemia. In this case, HDL2 should prove to be a sensitive index of lipolytic efficiency.

Adult↗