Barbara C. O'Brien

The effects of menopausal status and exercise training on serum lipids and the activities of intravascular enzymes related to lipid transport

The study purpose was to compare the effect of exercise training on serum lipid and apolipoprotein concentrations and the activities of intravascular enzymes related to lipid transport in previously untrained eumenorrheic, premenopausal (PRM) women (n = 21; mean age, 36 +/- 3 years) and estrogen-free postmenopausal (POM) women (n = 16; mean age, 68 +/- 8 years). Subjects trained at a progressive intensity and duration (50% to 75% maximal O2 consumption [VO2max], 200 to 300 kcal/session) 4 d/wk for 12 weeks. Before and after training, VO2max, body weight, relative body fat, and fasting blood samples were obtained following 2 weeks on a standardized diet designed to maintain body weight and during the early follicular stage for the PRM group. Blood samples were analyzed for serum total cholesterol (TC), triglyceride (TG), high-density lipoprotein cholesterol (HDL-C), the cholesterol content of the HDL3 subfraction, apolipoprotein (apo)A-I and apoB, lipoprotein(a), and the activity of lecithin:cholesterol acyltransferase (LCAT). Total and hepatic triglyceride lipase activity (HTGLA) were determined from plasma samples obtained after heparin administration. The cholesterol content of the low-density lipoprotein (LDL) and HDL2 subfractions and endothelial-bound lipoprotein lipase activity (LPLA) were calculated. A two (group) x two (time) multivariate ANOVA (MANOVA), with repeated measures for time indicated that the exercise-induced changes in physiological measurements, serum lipid or apolipoprotein concentrations, or enzyme activities did not differ between groups. Serum concentrations of TC, LDL-C, and HDL3 cholesterol, TG, and apo A-I and apoB were higher in POM women compared with the PRM group (P < .05 for all). For the combined groups, body weight and relative body fat did not change with training, but VO2max increased an average of 18.5% (P < .05). LPLA, HTGLA, and LCAT activity were unaltered with exercise training. Except for a small but significant decrease in HDL-C (-5.5%) and an elevation in apoB (4.3%; P < .05 for both), the concentrations of serum lipids and apolipoproteins did not change over the training period. We conclude that in previously untrained women, menopausal status does not influence the exercise training response of serum lipids or apolipoproteins or activities of intravascular enzymes related to lipid transport.

Influence of dietary soybean and egg lecithins on lipid responses in cholesterol-fed guinea pigs.

The comparative influence on plasma and tissue lipids of dietary soybean and egg lecithins, which have contrasting fatty acid compositions, was studied in the hypercholesterolemic guine apig. The polyunsaturated to saturated fatty acid (P/S) ratios of the soybean and egg lecithins were 3.4 and 0.38, respectively. Hypercholesterolemia was induced by feeding guinea pigs a purified diet that contained 15% lard enriched with 0.5% cholesterol. Subsequently, guinea pigs were fed for six wk the same diet supplemented with either soybean or egg lecithin as 7.5% of the diet. A control group continued to be fed the lecithin-free diet. Parameters measured included body weight and relative liver weight; in plasma, total cholesterol, high density lipoprotein cholesterol (HDLC), phospholipid, and nonesterified cholesterol; in liver, total fat, cholesterol, and the specific activity of the catabolic enzyme cholesterol 7α-hydroxylase; (EC 1.14.13.17); and in the aorta, cholesterol. Among the most noteworthy observations were the 49% decrease in total plasma cholesterol of the soybean lecithin group without decreasing HDLC and the 177% increase in HDLC of the egg lecithin group without a significant increase in total cholesterol compared with those values in the control group. These data suggest that dietary lecithin is particularly effective in increasing the HDLC/total cholesterol ratio in plasma. However, the absolute concentrations of those plasma lipids seem to depend upon the fatty acid composition of the lecithin.

Uranium: Further investigation of uranium content of Caribbean cores P6304-8 and P6304-9

Abstract Uranium content in P6304-8 and P6304-9 Caribbean cores is determined by thermal neutron activation followed by (1) Delayed neutron counting, and (2)132Te-fission product radiochemistry. The average value obtained by these two methods is 34% higher than that obtained previously by alpha-spectrometry.

Human plasma lipid and immunologic responses to eggs and ascorbic acid

Abstract The possibility that dietary eggs and ascorbic acid have a positive and synergistic influence on human high density lipoprotein (HDL) cholesterol was investigated. The influences of these diet variables on other plasma lipids and on some immune functions were also evaluated. Twenty men, ages 36 to 60 years, followed each of four, 12-week modifications of their daily habitual diet: no visible eggs or supplemental ascorbic acid (Basal); 3 eggs (EG); 1.5 g ascorbic acid (AA); and both 3 eggs and 1.5 g ascorbic acid (EGAA). Although average HDL cholesterol concentrations were unchanged by these diet modifications, HDL cholesterol was positively correlated with plasma levels of ascorbic acid. Total cholesterol was the only plasma lipid that was affected significantly by any of the treatments, and the difference was only between diets EG and AA (mean±SEM); 209±9 mg/dl and 194±6 mg/dl, respectively. These diet variables had no significant effect on plasma concentrations of immunoglobulins IgG, IgA, IgM, IgD, or complement C3 nor on mitogen-induced lymphoproliferation. However, the latter measure of immune response, mitogen-induced lymphoproliferation, tended to increase during the AA diet period. Although these data do not support an eggs-ascorbic acid synergism, ascorbic acid appears to play a role, as yet undefined, in cholesterol metabolism.