During the course of this study, an extensive investigation was conducted into the measurement of free and total cholesterol by fabrication of cholesterol biosensors. Specific areas investigated in-depth included the immobilisation of enzymes into conducting polypyrrole (PPy) film, bovine serum albumin-glutaraldehyde (BSA-GLA) gel and a hybrid bi-layer of PPy and BSA-GLA. Key parameters for the reliable measurement of cholesterol were optimised. The optimum parameters / Doctor of Philosophy (PhD)

No description available.

Proefschrift--Amsterdam. / "Stellingen" (2 leaves) laid in.

The purpose of this study was to investigate whether increased endogenous cholesterol synthesis contributes to the elevated plasma cholesterol levels observed in type III hyperlipoproteinemia (type III HLP). Eight apolipoprotein (apo) E2 subjects with type III HLP and 8 apo E2 non-hyperlipidemic control subjects (controls) were given a priming bolus dose of deuterium oxide (D₂O) (0.7 g D₂O/kg body H2O). Daily M1 (central) pool free cholesterol fractional synthetic rate (FSR) was calculated as the incorporation rate of deuterium from body water into plasma free cholesterol. Blood samples were collected one half hour prior to, and at 12 hour intervals over 48 hours following, the bolus D₂O dose. Drinking water labelled at 1.4 and 0.7 g D₂O/liter H₂O was given on the fed and fasted days, respectively. Over 0-24 hours, subjects consumed a diet of three isocaloric meals which, in composition, approximated average North American intakes. Subjects fasted over 24-48 hours. The deuterium enrichment of plasma free cholesterol and plasma water was determined by isotope ratio mass spectrometry. When all subjects were included, mean (±SEM) free cholesterol overall FSR in type III HLPs (0.031 ± 0.006 per day) was not significantly different from controls (0.037 ± 0.004 per day). Estimated Ml total cholesterol pool size in type III HLPs (26.1 ± 1.9 g) and controls (24.9 ± 0.6 g) was not significantly different. When free cholesterol net synthesis was calculated as the absolute amount of cholesterol synthesized per day, based on Ml total cholesterol pool size, overall free cholesterol net synthesis in type III HLPs (0.304 ± 0.034 g/day) was not significantly different from controls (0.364 ± 0.035 g/day). When all subjects were included, overall free cholesterol FSR and overall free cholesterol net synthesis were significantly greater (p<0.001) in the fed (0.066 ± 0.006 day⁻¹ and 0.655 + 0.048 g/day, respectively) as compared to the fasted state (0.001 ± 0.004 day⁻¹ and 0.010 ± 0.037 g/day, respectively). In the fed state, type III HLPs tended to synthesize cholesterol at a lower rate and in a lower absolute amount as compared to controls, while the reverse was observed in the fasted state. These results suggest that: (1) the elevated plasma cholesterol levels observed in type III HLPs are not due to excess de novo cholesterol synthesis; (2) fasting significantly reduces cholesterol synthesis from the fed state. / Land and Food Systems, Faculty of / Graduate

No description available.

No description available.

Purpose: To assess whether the participation in food assistance programs (Community Kitchens and Glass of Milk) was associated with lipid profile patterns in the Peruvian population. We conducted a secondary data analysis using data from the National Survey of Nutritional, Biochemical, Socioeconomic, and Cultural Indicators related to Chronic Degenerative Diseases. The sample included individuals aged ≥20 years, selected from five geographic strata in Peru. From each stratum a random sample of clusters was chosen. Different Poisson regression models with robust variance were built to determine the association between food assistance programs and participant lipid profile (total cholesterol (TC), HDL-cholesterol (HDL-c), LDL-cholesterol and triglycerides (TG)). Data from 4028 participants was analyzed, 123 (3.1%) reported being beneficiaries of the Community Kitchens program and 827 (20.5%) were beneficiaries of the Glass of Milk program. An association between being a beneficiary of Community Kitchens and increased LDL-c (Prevalence ratio (PR)= 2.33; 95% CI: 1.18–4.59) was found. Being a beneficiary of the Glass of Milk program increased the probability of having low HDL-c levels (PR= 1.08; 95% CI: 1.02–1.14), but reduced the probability of hypertriglyceridemia (PR= 0.70; 95% CI: 0.56–0.88). Being a beneficiary of the Community Kitchen program was associated with increased LDL-c levels; while, being a beneficiary of the Glass of Milk increased the probability of low HDL-c, but reduced the probability of developing hypertriglyceridemia. / Revisión por pares

To examine the effect of diet fat type on rates of cholesterol synthesis and esterification during feeding and fasting, nine healthy male subjects were fed solid-food diets of 40% fat as predominantly either olive oil (MONO), safflower-oil margarine (POLY), or butter (SAT). At the end of each two-week diet trial, subjects were given deuterium (D) oxide orally and de novo synthesis was measured from D incorporation into cholesterol and interpreted as rates of fractional synthesis (FSR) (pools/day) into the rapidly exchangeable free cholesterol (FC) pool. Absolute synthesis rates (ASR) were calculated as the product of FSR and the FC pool. Pool size for each subject was obtained from analysis of the specific activity decay curve of an intravenous injection of 4-14C-cholesterol over nine months. Synthesis was measured over two consecutive 12-h fed periods followed by two consecutive 12-h fasted periods. Serum samples were also assayed for lathosterol concentration, an index of cholesterol synthesis. Serum cholesterol and non-HDL cholesterol concentrations were highest on the SAT diet, lowest (P<0.001) on the POLY diet and intermediate on the MONO diet, triglyceride levels were greater (P<0.03) on the SAT diet than on the POLY diet, and HDL levels were lowest (P<0.05) on the SAT diet and highest on the MONO diet. Cholesterol D enrichment and FSR during each 12-h period were greater (P<0.014) on the POLY diet than on the SAT diet; MONO enrichment and FSR were not significantly different from those on the other two diets. Similar results were obtained for rates of cholesterol esterification (P<0.001). Deuterium enrichment data suggested, and lathosterol data confirmed, that free cholesterol synthesis was greater during the fed period than during the fasted period (P<0.01); however, this could not be confirmed for rates of cholesterol esterification. Results suggest that POLY fat feeding augments de novo cholesterol synthesis without adverse effects on total serum cholesterol concentrations, and that the deleterious effects of SAT fat on serum cholesterol are not brought about by augmented de novo synthesis. Finally, the combination of deuterium incorporation and mathematical modelling produces estimates of daily cholesterol synthesis which are compatible with those invoked by more laborious techniques.

Thesis (M.S.)--Virginia Polytechnic Institute and State University, 1990. / Vita. Abstract. Includes bibliographical references (leaves 34-38). Also available via the Internet.

The role of cholesterol-rich diet and of high protein supplement on the development of a glomerular lesion was studied in male guinea pigs. The possible pathogenesis of lipid-induced glomerulosclerosis was investigated. Four experiments were carried out. Four groups of guinea pigs were used in experiment I: CONT group was kept on normal guinea pig chow for 70 days; HC group was kept on 2% cholesterol diet for 70 days; HP group was kept on 50% casein diet for 70 days, and HCHP group received 2% cholesterol diet for 30 days and 2% cholesterol/50% casein diet for another 40 days. In experiment II two groups were used: CONT group and acetyl phenylhydrazine (APH)-treated group in which haemolytic anaemia was induced. In the third experiment the same dietary regimens as described in experiment I were used. In experiment IV three groups, namely CONT, HC, and HCHP, were employed. The animals in experiment IV were sacrificed after 5, 10, and 30 days. The first experiment explored the role of high cholesterol - and high cholesterol/high protein diet in the development of glomerulosclerosis. The other three experiments were designed to learn about the possible mechanism of lipid-induced glomerulosclerosis. Lipid analyses of plasma, erythrocytes and kidney tissue as well as complete blood count, erythrocyte osmotic fragility and blood cell morphology studies were performed. Kidney histology, histochemistry, immunohistochemistry, electron microscopy, morphometry, and renal and liver function tests were also carried out. De novo cholesterol synthesis was assessed by measuring HMG COA reductase activity and incorporation of tritiated water into cholesterol in the kidneys. Cholesterol-fed animals showed decreased weight gain, increased cholesterol concentration in plasma, erythrocytes, and kidney tissue. Haemolytic anaemia was documented after 70 days on this dietary regimen. Glomerular proliferation lesion was first noted at day 30 and progressed by day 70. Moderate proteinuria and haematuria were observed at day 70. Addition of protein to the high cholesterol diet led to a further decrease in weight gain. It also increased the mortality rate to 40% by day 70. The glomerular lesion, proteinuria and haematuria, and possibly haemolysis were more marked in the HCHP group. No causal relationship was found between liver function, immune complexes, haemolysis and glomerulosclerosis. Serum phosphate levels did not differ among the groups. The lipid found in the kidney of both HC and HCHP groups was mostly of plasma origin, since the kidney cholesterol de novo synthesis was suppressed in these two groups compared to the CONT group. There was a concommitant increase in the lipid content of kidney tissue and the mesangial expansion (MA/GTA) at day 30. No significant increase in the intraglomerular monocyte/macrophage was found at day 30 in the HCHP group compared to the HC group. However, a significant correlation (r=0.678, p 0.001) was found between the number of these cells and MA/GTA ratio among the four experimental groups at day 70. These data indicate that lipid deposits in kidney tissue may induce a glomerulosclerotic lesion in the absence of monocytes. However, these cells likely augment the proliferation of mesangial cells. We postulate that high protein diet could worsen the lipid-induced glomerular lesion by increasing delivery of abnormal lipoproteins to the kidney which could trigger mesangial cellular proliferation directly and indirectly by a macrophage-mediated process. / Medicine, Faculty of / Pathology and Laboratory Medicine, Department of / Graduate