PubMed Health⌕ Search

Biomedical subjects

S I Barr

Publications and source records attributed to S I Barr.

61 records · Page 4Linked to original sources
PubMed1985

Postprandial distribution of apolipoproteins C-II and C-III in normal subjects and patients with mild hypertriglyceridemia: comparison of meals containing corn oil and medium-chain triglyceride oil.

Five healthy male subjects and five patients with mild hypertriglyceridemia were studied following the administration of 800-kcal liquid meals containing 40% of energy from fat, 40% from carbohydrate, and 20% from protein. On the first day of the study, the fat source was corn oil (long-chain triglyceride), whereas medium-chain triglyceride (MCT) oil was used the second day. Meals were infused into the duodenum using a peristaltic pump. Plasma samples, obtained at hourly intervals for 8 hours, were analyzed for glucose, cholesterol, triglyceride, and apolipoproteins C-II and C-III. The distribution of apoC-II and apoC-III between ultracentrifugally-separated triglyceride-rich lipoproteins (TRL) and high-density lipoproteins (HDL) was also evaluated. The patient group had significantly elevated fasting levels of triglyceride, apoC-II and apoC-III, as well as much greater lipemic response to the meal containing corn oil. In both groups, TRL apoC-II and apoC-III levels were positively correlated with the triglyceride level as it increased following the corn oil meal. These correlations were also observed in the normal subjects when the MCT oil meal was administered, even though changes in plasma triglycerides were minimal. In normal subjects, whole plasma levels of apoC-II and apoC-III decreased significantly following the meal containing corn oil, whereas no net changes occurred following the MCT oil meal. In hypertriglyceridemic subjects, small decreases in plasma apoC-II and apoC-III levels occurred after both meals, although the changes in apoC-II were not statistically significant. The tendency for decreased plasma apoC levels following alimentary lipemia confirms previous reports, and provides further data to support the concept that some apoC is cleared from plasma in association with TRL remnants. The finding that mildly hypertriglyceridemic subjects responded similarly to both conventional fat and MCT may indicate that their rates of remnant clearance were similar following the two meals.

Adult↗
PubMed1984

Food intake of institutionalized women over 80 years of age.

Food intake of 30 women over 80 years of age and residing in a long-term care facility was determined for a five-day period using the weighed intake method. Purposes of the study were to examine the contribution to nutrient intake of foods from eight major food groups; to characterize intake by time of day; and to examine the effect of age on nutrient intake. The results indicated that intakes of calcium, thiamin, vitamin A, zinc, and protein were below recommended levels. Analysis of intake by food group revealed that the grain group was the primary source of energy and many nutrients. Percentage consumption of foods in this group was significantly higher than that of vegetables or meat and alternates. Analysis of intake by time of day indicated that more energy was consumed at breakfast than at dinner. Advanced age was negatively correlated with overall dietary adequacy, although the distribution of energy intake from the eight food groups did not change with age. Implications of the results, for these subjects and similar groups of elderly, are discussed.

Aged↗
PubMed1981

Immunochemistry of human plasma apolipoprotein C-II as studied by radioimmunoassay.

The immunoreactivity of human plasma apolipoprotein C-II was investigated using a specific radioimmunoassay. In whole plasma, the mean value quantitated was 2.21 +/- 0.415 mg/dl, while in delipidated plasma, a mean value of 3.84 +/- 1.186 mg/dl was obtained, suggesting that the antigenic sites of the apolipoprotein were not fully detected in unmodified plasma by our antibody preparation. Two detergents, Tween-20 and Triton X-100, were studied to determine if they could enhance the immunoreactivity of apolipoprotein C-II in whole plasma. At concentrations of 0.012-0.06%, Tween-20 markedly increased the immunoreactivity of whole plasma, but not of delipidated plasma, indicating that antigenic sites of plasma apolipoprotein C-II has been exposed by Tween-20. In contrast, Triton X-100 had no effect on the immunoreactivity of whole plasma apolipoprotein C-II. A radioimmunoassay conducted in the presence of 0.06% Tween-20, resulted in a mean value in whole plasma (3.39 +/- 1.11 mg/dl) that was not significantly different from that obtained when the assay was done on delipidated samples. The immunoreactivity of VLDL apolipoprotein C-II was also drastically enhanced following lipolysis by bovine milk lipoprotein lipase, supporting the hypothesis that antigenic sites are masked by the lipids. Finally, the mechanism responsible for the effect of Tween-20 on apolipoprotein C-II immunoreactivity was investigated. The results obtained from circular dichroism and ultracentrifugation suggest that the detergent may dissociate the apolipoprotein from lipoprotein particles, thus fully exposing the antigenic sites for reaction with antibodies.

Adult↗
PubMed1981

Postprandial exchange of apolipoprotein C-III between plasma lipoproteins.

Three healthy male subjects were given a high fat meal after fasting for 12 h. Blood samples were drawn at hourly intervals over 6 h. The plasma triglyceride levels reached peak values within 3 to 6 h postprandially. Plasma cholesterol concentration, however, remained constant in the three subjects as well as in a fasting normal subject. Apolipoprotein C-III (apoC-III), a major apoprotein in triglyceride-rich lipoprotein particles and known to be exchangeable between plasma high density lipoproteins (HDL) and triglyceride-rich particles, was studied in regard to its net transfer between lipoproteins during meal absorption and postabsorptive lipolysis. ApoC-III levels in total plasma as quantitated by radioimmunoassay were stable regardless of the increase of plasma triglycerides. When triglyceride levels increased after a meal, apoC-III in the d. less than 1.063 lipoprotein fraction increased concomitantly, while apoC-III in HDL decreased. The converse was observed during lipolysis as plasma triglycerides fell. In any case, apoC-III levels in d. less than 1.063 lipoproteins were positively correlated with plasma triglycerides (r = 0.82, p less than 0.01) after the meal. The finding suggests that the apoC-III concentrations in HDL are very dynamic in vivo. ApoC-III can transfer from HDL to triglyceride-rich particles during meal absorption and can transfer from triglyceride-rich particles to HDL during postabsorptive lipolysis.

Absorption↗
PubMedDate not supplied

Relative weight, weight loss efforts and nutrient intakes among health-conscious vegetarian, past vegetarian and nonvegetarian women ages 18 to 50.

OBJECTIVE: To compare relative weight, weight loss efforts and nutrient intakes among similarly health-conscious vegetarian, past vegetarian and nonvegetarian premenopausal women. METHODS: Demographic data, lifestyle practices and weight loss efforts (by questionnaire), body mass index (BMI;kg/m2) and dietary intake (via multiple-pass 24-hour diet recall) were compared in a convenience sample of 90 current vegetarians, 35 past vegetarians and 68 nonvegetarians. RESULTS: Age (31.9 +/- 8.8), educational attainment, smoking status, alcohol use, physical activity and perceived health status were similar among the three groups of women. BMI did not differ by dietary pattern and averaged 23.7 +/- 4.7 for all women combined. Participants had intentionally lost > or = 10 pounds a mean of 2.1 times, and 39% of women perceived themselves to be overweight; again, no differences were observed among dietary groups. Dietary intakes of vegetarians and current nonvegetarians were consistent with current recommendations for macronutrient composition (< 30% fat, < 10% saturates). Compared to current nonvegetarians, current vegetarians had lower intakes of protein, saturated fat, cholesterol, niacin, vitamins B12 and D, and higher fiber and magnesium intakes. Vegetarians' mean vitamin B12 and D intakes were well below recommendations. CONCLUSIONS: Relative weight and weight loss efforts do not differ by dietary pattern among similarly health-conscious vegetarian and nonvegetarian women. The only differences in nutrient intake with potential health implications were vitamins D and B12.

Adolescent↗