| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Screening of microbial secondary metabolites inhibiting cholesterol biosynthesis with the use of hepatoblastoma G2 Trenin, A. S., L. P. Terekhova, et al. (2003), Antibiot Khimioter 48(1): 3-8. Abstract: The culture of hepatoblastoma G2 (Hep G2) cells is proposed as an effective model for screening of microbial metabolites--inhibitors of sterol biosynthesis. This model can be applied at early stages of screening procedures and is quite effective for testing of crude extracts of producers' culture broth. The test is based on measurement inhibition of the radiolabelled precursors incorporation in cholesterol and separate fractions of lipids by microbial metabolites in Hep G2 cells. That allows not only to reveal inhibitors of cholesterol biosynthesis, but also to evaluate mechanism of action, including ability to inhibit the synthesis of cholesterol ethers. The cholesterol biosynthesis inhibition was tested at 150 microbial cultures (actinomycetes and imperfect fungi), isolated from soil. The ability to inhibit 14C-acetate incorporation into cholesterol was found in 15-20% of microbial cultures possessing antifungal activity of extracts (culture broth and mycelium). |
| Screening with total cholesterol: determining sensitivity and specificity of the National Cholesterol Education Program's guidelines from a population survey Gelskey, D. E., T. K. Young, et al. (1994), J Clin Epidemiol 47(5): 547-53. Abstract: The objective of the study was to determine the sensitivity and specificity of the National Cholesterol Education Program (NCEP) guidelines in identifying at-risk individuals for hypercholesterolemia, using population-based data from the Manitoba Heart Health Survey (MHHS). The MHHS surveyed a representative sample of adult residents of the province of Manitoba, Canada, aged 18-74 (n = 2792), 2212 of whom underwent complete lipoprotein analyses: total cholesterol (TC), high-density (HDL) and low-density (LDL) lipoprotein cholesterol, and triglycerides (TG) after overnight fasting. Following NCEP criteria for risk categories, 618 individuals could be considered as "at risk" based on their HDL and/or LDL levels. However, if the NCEP algorithms were followed, i.e. initial screen for TC only, and determination of HDL and LDL for selected individuals with borderline and high TC, only 438 of the total "at risk" individuals would have been identified (sensitivity = 71%). 1203 of 1594 individuals with acceptable HDL and LDL levels were not considered "at risk" on screening (specificity = 76%). If "at risk" status was determined solely on LDL criteria, the NCEP guidelines result in a higher sensitivity (94%) and comparable specificity (76%). However, when only HDL criteria were used, the sensitivity and specificity declined to 38% and 63% respectively. Compared to a simulated screening study based on the Lipid Research Clinic data reported by Bush and Riedel (1991) the estimates of sensitivity from the MHHS were high. Current NCEP guidelines appear to balance optimally the sensitivity and specificity for selecting individuals based on TC levels for further complete lipoprotein analysis.(ABSTRACT TRUNCATED AT 250 WORDS) |
| Seasonal and biological variation of blood concentrations of total cholesterol, dehydroepiandrosterone sulfate, hemoglobin A(1c), IgA, prolactin, and free testosterone in healthy women Garde, A. H., A. M. Hansen, et al. (2000), Clin Chem 46(4): 551-9. Abstract: BACKGROUND: Concentrations of physiological response variables fluctuate over time. The present study describes within-day and seasonal fluctuations for total cholesterol, dehydroepiandrosterone sulfate (DHEA-S), hemoglobin A(1c) (HbA(1c)), IgA, prolactin, and free testosterone in blood, and estimates within- (CV(i)) and between-subject (CV(g)) CVs for healthy women. In addition, the index of individuality, prediction intervals, and power calculations were derived. METHODS: A total of 21 healthy female subjects participated in the study. Using a random effects analysis of variance, we estimated CV(g) and total within-subject variation (CV(ti)), i.e., the combined within-subject and analytical variation, from logarithmically transformed data. Analytical variation was subtracted from CV(ti) to give CV(i). CV(i) was estimated from samples taken monthly during 1 year (CV(iy)), weekly during 1 month (CV(im)), and six times within 1 day (CV(id)). RESULTS: A cyclic seasonal variation was demonstrated for total cholesterol, DHEA-S, HbA(1c), prolactin, and free testosterone. Within-day variation was shown for prolactin and free testosterone. The overall mean values for the group and the variability (CV(iy) and CV(g)) were: 5.1 mmol/L, 13% corrected, and 12% corrected for total cholesterol; 6.6 micromol/L, 20% corrected, and 49% corrected for DHEA-S; 30% corrected, 7.0% corrected, and 7.5% corrected for HbA(1c)/hemoglobin(total); 2.1 g/L, 5.9%, and 13% for IgA; 136 mIU/L, 58% corrected, and 63% corrected for prolactin; and 5.4 pmol/L, 55% corrected, and 68% corrected for free testosterone. CONCLUSIONS: Collecting samples at specific hours of the day or times of the year may reduce high biological variation. Alternatively, the number of individuals may be increased and a paired study design chosen to obtain adequate statistical power. |
| Seasonal and climatic variation in cholesterol and vitamin C: effect of vitamin C supplementation MacRury, S. M., M. Muir, et al. (1992), Scott Med J 37(2): 49-52. Abstract: Vitamin C (ascorbic acid) is an important anti-oxidant which may help to reduce free radical damage and atheroma formation in blood vessels. In a study in which a group of healthy volunteer subjects were followed up for 12 months and a group of patients with vascular disease taking Vitamin C supplements were followed for 23 months, we confirmed previous findings of seasonal variations in ascorbic acid and cholesterol and have shown an inverse relationship between leucocyte ascorbic acid and serum cholesterol levels. In healthy control subjects the increase in ascorbate and fall in cholesterol during the summer months was reversed when the weather changed to a more winter pattern, presumably due to dietary alterations. We found that ascorbic acid levels were lower in patients with peripheral vascular disease and that although normal ascorbic acid levels were achieved with Vitamin C supplementation, when supplements were stopped at the height of a normal summer, there was a fall in ascorbic acid and a rise in serum cholesterol to winter levels. Given these findings we suggest that patients with vascular disease should have Vitamin C supplements throughout the year. |
| Seasonal variation in high density lipoprotein cholesterol Manttari, M., K. Javela, et al. (1993), Atherosclerosis 100(2): 257-65. Abstract: We investigated the seasonal variation in high density lipoprotein cholesterol (HDL) in 142 dyslipidemic (non-HDL-cholesterol > or = 5.2 mmol/l) middle-aged men in the placebo group of the Helsinki Heart Study over the 5-year trial period. A seasonal pattern was found in HDL fluctuation, with a 4.5% drop during mid-winter (5-year mean 1.192 +/- 0.265 mmol/l) compared with a stable level (5-year mean 1.248 +/- 0.281 mmol/l) during the rest of the year (P < 0.001). A less pronounced seasonal variation in HDL was observed in 85 subjects receiving gemfibrozil. Although affecting pretrial HDL level in cross-sectional analyses, age, alcohol consumption, dietary adherence, physical activity and serum triglycerides had no influence on the seasonality of HDL variation. Smoking had a slight attenuating effect on the variation pattern. Pretrial HDL was influenced by relative weight, but there was also an inverse relationship between HDL and body weight variations, i.e. the annual drop in HDL coincided with the annual peak in body weight. However, seasonal HDL variation was not directly reflected in the annual variation in CHD incidence. |
| Seasonal variation in household, occupational, and leisure time physical activity: longitudinal analyses from the seasonal variation of blood cholesterol study Matthews, C. E., P. S. Freedson, et al. (2001), Am J Epidemiol 153(2): 172-83. Abstract: The authors examined seasonal variation in physical activity in longitudinal analyses of 580 healthy adults from Worcester, Massachusetts (the Seasonal Variation of Blood Cholesterol Study, 1994-1998). Three 24-hour physical activity recalls administered five times during 12 months of follow-up were used to estimate household, occupational, leisure time, and total physical activity levels in metabolic equivalent (MET)-hours/day. Trigonometric models were used to estimate the peak-to-trough amplitude and phase of the peaks in activity during the year. Total activity increased by 1.4 MET-hours/day (121 kcal/day) in men and 1.0 MET-hours/day (70 kcal/day) in women during the summer in comparison with winter. Moderate intensity nonoccupational activity increased by 2.0-2.4 MET-hours/day in the summer. During the summer, objectively measured mean physical activity increased by 51 minutes/day (95% confidence interval: 20, 82) in men and by 16 minutes/day (95% confidence interval: -12, 45) in women. The authors observed complex patterns of seasonal change that varied in amplitude and phase by type and intensity of activity and by subject characteristics (i.e., age, obesity, and exercise). These findings have important implications for clinical research studies examining the health effects of physical activity and for health promotion efforts designed to increase population levels of physical activity. |
| Seasonal variation in plasma cholesterol distributions: implications for screening and referral Rastam, L., P. J. Hannan, et al. (1992), Am J Prev Med 8(6): 360-6. Abstract: In 3,377 men and 3,900 women who participated in a community-based plasma cholesterol screening program, we found a significant cyclic time-trend in cholesterol levels, with maximum peak in January. The 95% confidence interval (CI) of the peak to trough distance was 5.8-13.8 mg/dL (0.15-0.36 mmol/L) in men, corresponding to 2.6%-6.3% of the average cholesterol level. Corresponding figures for women were 2.0-9.3 mg/dL (0.05-0.24 mmol/L) or 1.0%-4.6%. Applying the cutoff level for high cholesterol risk proposed by the National Cholesterol Education Program (< or = 240 mg/dL 6.21 mmol/L) to sex-specific bimonthly distributions, we found a statistically significant variation in prevalence, attributable to seasonal trends, in men (P <.01), but not in women. In men, the age-adjusted prevalence in winter (25.4%) was double that in the summer (13.5%). Seasonal variation is an important determinant of the prevalence of hypercholesterolemia in men and should be considered in patient follow-up and screening. |
| Seasonal variation in serum cholesterol levels in health screening populations from the U.K. and Japan Robinson, D., S. Hinohara, et al. (1993), J Med Syst 17(3-4): 207-11. Abstract: We have performed time series analyses on data from 140,000 men and 32,000 women in the U.K. and 30,000 men and 12,000 women in Japan, seen over periods ranging from 4 to 6 1/2 years, in order to test for seasonal variation in serum cholesterol levels. In both countries and both sexes we found a strong seasonal effect, with mean cholesterol levels being some three to five percent higher in winter than in summer. Mean monthly cholesterol levels were negatively correlated with mean monthly air temperatures (r = -0.60 to -0.71). The seasonal differences observed were independent of changes in body weight, and have important implications both for long-term epidemiological or follow-up studies, and for the interpretation of patient data. |
| Seasonal variation in serum cholesterol levels: another piece in the puzzle of the winter excess of cardiovascular deaths? Manfredini, R. and B. Boari (2004), Arch Intern Med 164(22): 2505-6; author reply 2506-7. |
| Seasonal variation in serum cholesterol levels: treatment implications and possible mechanisms Ockene, I. S., D. E. Chiriboga, et al. (2004), Arch Intern Med 164(8): 863-70. Abstract: BACKGROUND: A variety of studies have noted seasonal variation in blood lipid levels. Although the mechanism for this phenomenon is not clear, such variation could result in larger numbers of people being diagnosed as having hypercholesterolemia during the winter. METHODS: We conducted a longitudinal study of seasonal variation in lipid levels in 517 healthy volunteers from a health maintenance organization serving central Massachusetts. Data collected during a 12-month period for each individual included baseline demographics and quarterly anthropometric, blood lipid, dietary, physical activity, light exposure, and behavioral information. Data were analyzed using sinusoidal regression modeling techniques. RESULTS: The average total cholesterol level was 222 mg/dL (5.75 mmol/L) in men and 213 mg/dL (5.52 mmol/L) in women. Amplitude of seasonal variation was 3.9 mg/dL (0.10 mmol/L) in men, with a peak in December, and 5.4 mg/dL (0.14 mmol/L) in women, with a peak in January. Seasonal amplitude was greater in hypercholesterolemic participants. Seasonal changes in plasma volume explained a substantial proportion of the observed variation. Overall, 22% more participants had total cholesterol levels of 240 mg/dL or greater (> or =6.22 mmol/L) in the winter than in the summer. CONCLUSIONS: This study confirms seasonal variation in blood lipid levels and suggests greater amplitude in seasonal variability in women and hypercholesterolemic individuals, with changes in plasma volume accounting for much of the variation. A relative plasma hypervolemia during the summer seems to be linked to increases in temperature and/or physical activity. These findings have implications for lipid screening guidelines. Further research is needed to better understand the effects of a relative winter hemoconcentration. |
| Seasonal variation in serum cholesterol levels--evidence from the UK and Japan Robinson, D., E. A. Bevan, et al. (1992), Atherosclerosis 95(1): 15-24. Abstract: Using data from 140,000 men and 32,000 women in the UK and 30,000 men and 12,000 women in Japan, we performed spectral analyses to test for seasonal variation in serum cholesterol levels. In both countries and both sexes we found a strong seasonal effect, cholesterol levels being some 3-5% higher in winter than in summer. This was independent of seasonal changes in body mass. Mean monthly cholesterol levels were negatively correlated with mean monthly air temperatures (r = -0.60 to -0.71). The observed seasonal differences were larger than the inter-assay coefficient of variation for the cholesterol determination method employed and have important consequences for long-term epidemiological or intervention studies. |
| Seasonal variation in serum total concentrations of cholesterol and protein in elderly subjects Fujimura, A., K. Ohashi, et al. (1992), Clin Chim Acta 212(1-2): 85-7. |
| Seasonal variation of blood cholesterol levels: study methodology Merriam, P. A., I. S. Ockene, et al. (1999), J Biol Rhythms 14(4): 330-9. Abstract: This manuscript provides a description of the methodology used in the Seasonal Variation of Blood Cholesterol Levels (SEASON) study, with the intent of informing the scientific community of the available data sets and to invite a dialogue with scientists in complementary fields. The primary aim of the SEASON study is to describe and delineate the causes of seasonal variation of blood lipid levels in the general population. This research project is designed specifically to systematically collect and analyze a number of important variables necessary to study the role of seasonality in blood lipids and relevant covariates. |
| Seasonal variations of serum cholesterol detected in the Bucharest Multifactorial Prevention Trial of Coronary Heart Disease. Ten years follow-up (1971-1982) Cucu, F., S. Purice, et al. (1991), Rom J Intern Med 29(1-2): 15-21. Abstract: A group of 4800 men, aged fourty to sixty at entry, subjected to a multifactorial prevention trial of coronary heart disease for a ten-year period, showed spontaneous seasonal variations of serum cholesterol, characterized by increases in winter and decreases in summer. The authors discuss the relationship between the food changes and the seasonal variation of serum cholesterol values. |
| Secondary metabolites by chemical screening. 8. Decarestrictines, a new family of inhibitors of cholesterol biosynthesis from Penicillium. I. Strain description, fermentation, isolation and properties Grabley, S., E. Granzer, et al. (1992), J Antibiot (Tokyo) 45(1): 56-65. Abstract: A family of new 10-membered lactones was detected by chemical screening. Taxonomic studies and fermentation conditions of the producing organisms, which belong to the species Penicillium simplicissimum and Penicillium corylophilum, are presented. The isolation as well as physico-chemical data of the new compounds named decarestrictines A to D are reported. In vitro testing using the HEP-G2 cell assay showed the decarestrictines to be inhibitors of cholesterol biosynthesis, which could be confirmed in vivo. In addition to the decarestrictines from P. corylophilum epoxyagroclavine-I (1) was isolated. |
| Secondary prevention in coronary heart disease. Fact: lowering cholesterol saves lives McKenna, C. J. and D. D. Sugrue (1995), Ir Med J 88(6): 191. |
| Secondary prevention in patients with a coronary disorder: wider indication for cholesterol-lowering drugs Peters, R. J. (1995), Ned Tijdschr Geneeskd 139(12): 604-6. |
| Secondary prevention: a low-density lipoprotein cholesterol of < or = 100 mg/dl Citkowitz, E. (1994), Am J Cardiol 73(12): 934. |
| Secretion of lipoprotein cholesterol by perfused livers from rabbits hypo- or hyperresponsive to dietary cholesterol: greater dietary cholesterol-induced secretion in hyperresponsive rabbits Meijer, G. W., J. G. Van der Palen, et al. (1992), J Nutr 122(5): 1164-73. Abstract: In two inbred strains of rabbits with high or low response of plasma cholesterol to dietary cholesterol, secretion of lipoprotein cholesterol by perfused livers was determined. The perfused rabbit livers secreted cholesterol into the perfusate at essentially constant rates between 30 and 120 min of perfusion. Most of the secreted cholesterol resided in VLDL. Addition of cholesterol to the diet of the donor rabbits caused a higher cholesterol:triglyceride ratio of lipoproteins secreted by the perfused liver. Such a rise was also seen in the plasma lipoproteins of cholesterol-fed rabbits. Plasma and perfusate lipoproteins differed in that the former had a higher cholesterol:triglyceride ratio. Cholesterol feeding produced a higher output of lipoprotein cholesterol by the perfused liver, the increment being greater in hyper- than in hyporesponders. Cholesterol-fed hyperresponders had higher liver cholesterol concentrations than their hyporesponsive counterparts. There was a direct relationship between the rise of liver cholesterol concentrations and the rise of hepatic secretion of lipoprotein cholesterol; this relationship was identical for hypo- and hyperresponders. We conclude that the higher cholesterolemic response to cholesterol feeding in the hyperresponders, when compared with the hyporesponders, can be explained, at least partly, by a greater cholesterol-induced hepatic secretion of lipoprotein cholesterol. |
| Secretogranin III binds to cholesterol in the secretory granule membrane as an adapter for chromogranin A Hosaka, M., M. Suda, et al. (2004), J Biol Chem 279(5): 3627-34. Abstract: Granin-family proteins, including chromogranin A (CgA) and secretogranin III (SgIII), are transported to secretory granules (SGs) in neuroendocrine cells. We previously showed that SgIII binds strongly to CgA in an intragranular milieu and targets CgA to SGs in pituitary and pancreatic endocrine cells. In this study, we demonstrated that with a sucrose density gradient of rat insulinoma-derived INS-1 cell homogenates, SgIII was localized to the SG fraction and was fractionated to the SG membrane (SGM) despite lacking the transmembrane region. With depletion of cholesterol from the SGM using methyl-beta-cyclodextrin, SgIII was impaired to bind to the SGM. Both SgIII and CgA were solubilized from the SGM by Triton X-100 in contrast to the Triton X-100 insolubility of carboxypeptidase E. SgIII and carboxypeptidase E strongly bound to the SGM-type liposome in intragranular conditions, but CgA did not. Instead, CgA bound to the SGM-type liposome only in the presence of SgIII. Immunocytochemical and pulse-chase experiments revealed that SgIII deleting the N-terminal lipid-binding region missorted to the constitutive pathway in mouse corticotroph-derived AtT-20 cells. Thus, we suggest that SgIII directly binds to cholesterol components of the SGM and targets CgA to SGs in pituitary and pancreatic endocrine cells. |