| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Community-based cholesterol screening and education to prevent heart disease: five-year results of the North Coast Cholesterol Check Campaign van Beurden, E., R. James, et al. (1993), Aust J Public Health 17(2): 109-16. Abstract: A cardiovascular disease screening and education campaign was conducted throughout the North Coast Region of New South Wales from 1987 to 1991. Objectives were: to screen 20 per cent of the adult population for blood cholesterol and other heart disease risk factors; to raise awareness of the risks associated with a high-fat diet; to provide nutrition counselling and referral advice for those with elevated cholesterol; and to monitor these participants' cholesterol levels with a follow-up test at three months. During the five years, 42,869 individuals or 18 per cent of North Coast adults participated, with some overrepresentation of women aged 40 to 60 years. Initially, 65 per cent of participants had elevated cholesterol levels (> or = 5.5 mmol/L) and 46 per cent were overweight (body mass index over 25). A three-month retest was offered to all participants with elevated cholesterol, of whom 53 per cent attended. Participants who received nutrition counselling generally reported dietary changes which were reflected in significant cholesterol and weight reductions. Of participants who attended retest, 63 to 87 per cent had reduced cholesterol levels and 57 to 71 per cent reduced weight. A stratified random sample of participants was retested at one and three years. Reductions in cholesterol were well maintained for one year but showed signs of relapse after three years. There was a tendency for initially lower cholesterol levels to increase over a three-year period. Contributing factors included aging, regression to the mean and complacency. Maintenance may be enhanced by regular reinforcement of nutrition changes and development of more supportive environments. |
| Community-based study on the relationship between serum cholesterol/triglyceride and dietary habits/life styles in Pu-Li, Taiwan Chou, P., C. K. Shaw, et al. (1993), Zhonghua Yi Xue Za Zhi (Taipei) 52(3): 155-60. Abstract: This is a community-based study on the relationship between serum cholesterol (CHO)/triglyceride (TG) and dietary habits/life styles of persons living in a central Taiwan Town. Door-to-door interviews were carried out by the Yang-Ming Crusade, and fasting blood for CHO and TG tests was drawn by public health nurses from Pu-Li Health Station. Univariate analysis found that significant variables correlated with CHO were age (+), locality, non-fish seafood (+) and pungent food (+). Significant variables correlated with TG were age (+), sex, locality, smoking (+), alcohol (+) and physical activity (-). Stratified by age (> or = 50 and < 50) and by sex respectively, only one significant interaction item--age x organ meat consumption--was found; those who consumed organ meat more frequently had higher TG, if they were less than 50 years of age. This was not true for those aged 50 and over. Multivariate analysis using logistic regression revealed that after controlling for all of the other covariates, significant variables correlated with CHO were age (OR = 1.92, 95% C.I. = 1.37-2.69), pungent food (OR = 1.91, 95% C.I. = 1.26-2.89); locality (OR = 0.53, 95% C.I. = 0.35-0.80 for sub urban area; and OR = 0.74, 95% C.I. = 0.50-1.08 for rural area); sea food consumption (OR = 1.50, 95% C.I. = 0.94-2.40); and smoking (OR = 0.69, 95% C.I. = 0.48-0.99).(ABSTRACT TRUNCATED AT 250 WORDS) |
| Commutability of control materials in cholesterol measurement Franzini, C. and P. Luraschi (1993), Scand J Clin Lab Invest 53(1): 51-5. Abstract: The 'commutability' is the property of a material to show inter-assay changes comparable to those of patients' sera. In order to assess the commutability, the cholesterol concentration was measured in 107 patients' sera and in 24 lyophilized control materials by a direct enzymatic method and by a reference-class procedure. The distance from the regression line of patients' sera results, expressed in SD units (normalized residual), was calculated and used to assess the commutability of each material. Out of 24 materials tested one had a normalized residual outside the +/- 3 interval (-4.4), and was considered as non-commutable. However, the distribution of the normalized residuals from the remaining 23 materials suggested a different behaviour in comparison with patients' sera, in the specific pair of methods. The relevance of this finding to the control of accuracy is discussed. |
| Comparability of lipoprotein measurements, total:HDL cholesterol ratio and other coronary risk functions within and between laboratories in Australia Chennell, A., D. R. Sullivan, et al. (1994), Pathology 26(4): 471-6. Abstract: We assessed the intralaboratory imprecision and interlaboratory comparability of lipoprotein measurements and related cardiovascular risk functions such as the total to high density lipoprotein cholesterol (TC:HDL) ratio. Analysis of 5 separate plasma pools was carried out in 4 laboratories which regularly perform lipoprotein testing. We also performed a retrospective audit on RCPA-AACB Quality Assurance Programme data from 134 laboratories participating in the Special Lipid Programme in 1991. Intralaboratory imprecision and interlaboratory comparability are reported as coefficient of variation (cv) and its 95% confidence limit. For the national data, we calculated the percentage of laboratories within specified ranges (+/- 3, 5 or 10%) about the national mean (or median) for a given level of each analyte. Intralaboratory imprecision and interlaboratory comparability amongst the 4 laboratories were close to, or within recommended limits for, TC, TG and HDL, but the interlaboratory comparability of LDL and coronary risk functions exceeded these limits. On a national level, interlaboratory comparability of TC:HDL was within +/- 5% for only 43% of laboratories, and even fewer (26%) were within this range at higher values of the ratio. We conclude that it is not possible to recommend the use of coronary risk functions at present because of sub-optimal interlaboratory comparability. Even if measures are introduced to overcome this problem, coronary risk functions may over-simplify coronary vascular disease risk in a variety of clinical situations. |
| Comparable efficacy of hydrogenated versus nonhydrogenated plant sterol esters on circulating cholesterol levels in humans Jones, P. J. and F. Ntanios (1998), Nutr Rev 56(8): 245-8. Abstract: A recent study in The Netherlands compared the effects of margarine enriched with different vegetable oil sterols with margarine containing sitostanol-ester on plasma total, low-density lipoprotein (LDL), and high-density lipoprotein (HDL) cholesterol concentrations. Margarine with sterolesters from soybean oil (mainly esters from sitosterol, campesterol, and stigmasterol) was as effective as a margarine with sitostanol-ester in lowering blood total and LDL cholesterol levels without affecting HDL cholesterol levels. |
| Comparative affinity of steroidal and non-steroidal antioestrogens, cholesterol derivatives and compounds with a dialkylamino side chain for the rat liver antioestrogen binding site van den Koedijk, C. D., C. Vis van Heemst, et al. (1992), Biochem Pharmacol 43(12): 2511-8. Abstract: Steroidal and non-steroidal antioestrogens, steroidal compounds with (disubstituted) dialkyl amino side chain, cholesterol derivatives, histaminic and (anti)-progestational compounds were tested for their ability to compete with 3Htamoxifen for the specific antioestrogen binding site (AEBS) in the post-mitochondrial fraction of rat liver homogenates. Relative binding affinity was highest for compounds with diethylamino or pyrrolidino ethoxy side chains. Affinity decreased with shortening of this side chain. No connection could be established between the carbon backbone of the compound and affinity, except for the presence of (sometimes aromatic) ring structures. Steroidal ring structures do not seem to be necessary for binding. The cholesterol derivatives, tested in our laboratory, showed very little affinity for the rat liver AEBS. Histamine, melatonin and the (anti)-progestational compounds showed no affinity for the AEBS; and we therefore conclude that the AEBS is not identical to receptors for these compounds. Results of these experiments could be useful in other investigations on the development of resistance of breast cancer to antioestrogens. |
| Comparative analysis of biochemical parameters for differentiation of pleural exudates from transudates Light's criteria, cholesterol, bilirubin, albumin gradient, alkaline phosphatase, creatine kinase, and uric acid Metintas, M., O. Alatas, et al. (1997), Clin Chim Acta 264(2): 149-62. Abstract: The differentiation of pleural effusions as being either transudate or exudate is the first step in the diagnosis of pleural effusions. The aim of this study was to compare the efficiency of the various biochemical parameters to the traditional criteria of Light et al., for differentiating exudates from transudates. Ninety-three pleural fluid and sera specimens were obtained and classified as transudates or exudates on the basis of their diagnosis. Of the 93 pleural fluids, 21 were transudates, 72 were exudates. The efficiencies of different parameters for detection of exudates were as follows: The criteria of Light 96%; effusion cholesterol concentration 77%; serum-fluid albumin gradient 67%, pleural/serum alkaline phosphatase ratio 83%; effusion creatine kinase levels 91%; pleural/serum creatine kinase ratio 83%, and effusion uric acid 71%. Pleural/serum uric acid ratio was insignificant for the purpose of this study. |
| Comparative analysis of cholesterol transport in bile from patients with and without cholesterol gallstones Pattinson, N. R., K. E. Willis, et al. (1991), J Lipid Res 32(2): 205-14. Abstract: Aggregation of cholesterol-phospholipid vesicles in supersaturated biles precedes cholesterol crystal formation. In this study we examined the relationship between the percentage of cholesterol carried by vesicles and/or their composition and the propensity to form cholesterol crystals (nucleation time). Bile (common bile duct, gallbladder and T-tube) was obtained from patients with and without gallstones. Gel filtration chromatography resolved three peaks, a void volume vesicle, a smaller vesicle (identified by electron microscopy and of distinct composition compared to the larger void volume vesicle), and the mixed micelle. The void volume vesicle was present in 11 of 28 abnormal gallbladder biles, but in none of the 10 normal gallbladder biles. Despite this difference, no correlation between the nucleation time of whole bile with either the percentage of cholesterol carried by or cholesterol/phospholipid ratio of the void volume vesicle was found. Nucleation time was, however, found to correlate with the composition of the small-vesicular transport form. No significant difference in the composition or percentage of the small-vesicular form or the combined vesicular forms was found between normal and abnormal gallbladder biles, although the latter nucleated significantly more rapidly. Our results confirm the importance of vesicles in the nucleation process but suggest that other factors, not yet identified, appear to be responsible for the more rapid nucleation seen in abnormal gallbladder biles. |
| Comparative characteristics of lipids, lipoproteins and free radical processes in blood of rabbits after ionizing irradiation and dietary cholesterol administration Chobot'ko, G. M. (1998), Radiats Biol Radioecol 38(4): 535-41. Abstract: Comparative study of spectrum of lypoids and lipoproteins has been conducted and also of parameters of free radical processes in blood after exposure of organisms of experimental animals to ionizing irradiation in dose of 5 Gy and inclusion of cholesterol into diet. Intake of cholesterol to experimental animals irradiated caused specific impact on indices studied testifying about deep changes in metabolism. It is important during analysis of complex set of postradiation metabolic symptoms observed in clinics. |
| Comparative characterization of the lipoprotein spectrum and status of free radical processes in the blood of rabbits exposed to external gamma-irradiation and cholesterol administration Chobot'ko, G. M., P. P. Chaialo, et al. (1992), Ukr Biokhim Zh 64(5): 66-70. Abstract: Characteristic of lipoprotein spectrum and state of free-radical processes in the animals under action of ionizing radiation and cholesterin diet are comparatively studied. The content of lipids in the blood serum increases on the 5th day after irradiation and then decreases on the 15th and 30th days. Cholesterin diet increases the content of cholesterin under practically unchanged content of triglycerides in the blood serum in all the terms of investigations. Total decrease of the intensity of induced chemiluminescence of the blood serum and erythrocytes after irradiation is shown. Peroral introduction of cholesterin evokes differently directed changes in the light sum of chemiluminescence--a decrease in erythrocytes and increase in the blood serum. |
| Comparative cholesterol lowering properties of vegetable oils: beyond fatty acids Wilson, T. A., L. M. Ausman, et al. (2000), J Am Coll Nutr 19(5): 601-7. Abstract: OBJECTIVE: Our laboratory has previously reported that the hypolipidemic effect of rice bran oil (RBO) is not entirely explained by its fatty acid composition. Although RBO has up to three times more serum cholesterol-raising saturated fatty acids (SATS) than some unsaturated vegetable oils, we hypothesized that its greater content of the unsaponifiables would compensate for its high SATS and yield comparable cholesterol-lowering properties to other vegetable oils with less SATS. METHODS: To study the comparative effects of different unsaturated vegetable oils on serum lipoprotein levels, nine cynomologus monkeys (Macaca fascicularis) were fed diets, for four weeks, in a Latin square design, containing rice bran, canola or corn oils (as 20% of energy) in a basal mixture of other fats to yield a final dietary fat concentration of 30% of energy. All animals were fed a baseline diet containing 36% of energy as fat with 15% SATS, 15% monounsaturated fatty acids (MONOS) and 6% polyunsaturated fatty acids (POLYS). RESULTS: Despite the lower SATS and higher MONOS content of canola oil and the higher POLYS content of corn oil, RBO produced similar reductions in serum total cholesterol (TC) (-25%) and low density lipoprotein cholesterol (LDL-C) (-30%). In addition, as compared to the baseline diet, the reduction in serum TC and LDL-C cholesterol with RBO was not accompanied by reductions in high density lipoprotein cholesterol (HDL-C) which occurred with the other two dietary oils. Using predictive equations developed from data gathered from several studies with non-human primates, we noted that the observed serum TC and LDL-C lowering capabilities of the RBO diet were in excess of those predicted based on the fatty acid composition of RBO. CONCLUSIONS: These studies suggest that non-fatty acid components (unsaponifiables) of RBO can contribute significantly to its cholesterol-lowering capability. |
| Comparative determinations of low-density-lipoprotein-cholesterol Sanchez-Muniz, F. J., C. Cuesta, et al. (1992), Rev Esp Fisiol 48(4): 271-6. Abstract: Two different methods for low-density-lipoprotein-cholesterol (LDL-C) determination were comparatively used. The heparin-sodium citrate (pH 5.12) precipitation method gave similar LDL-C results to the ones given by the Friedewald et al. formula (3.2 vs 3.3 mmol/l) in 187 men. Values obtained using both methods show a very high and significant correlation (r > 0.9; p < 0.001). However, LDL-C values obtained with the precipitation method were 15% higher in hypertriglyceridemics (triglycerides (Tg) > or = 2.3 mmol/l). A paired-comparison between data obtained by both methods indicates a clear serum Tg-values influence, because LDL-C values obtained by the precipitation method were significantly more frequently higher (p < 0.05 or p < 0.01) than LDL-C values obtained using the Friedewald's formula in hypertriglyceridemic men (Tg > or = 1.7 mmol/l or Tg > or = 2.3 mmol/l respectively). When a 3.9 mmol/l LDL-C level break was chosen, Friedewald's formula gave 13% false hypercholesterolemics. The influence of Tg was again significant in men with both, hypercholesterolemia and hypertriglyceridemia, while LDL-C values obtained by the precipitation method were significantly more frequently higher (p < 0.01). |
| Comparative differential scanning calorimetric and FTIR and 31P-NMR spectroscopic studies of the effects of cholesterol and androstenol on the thermotropic phase behavior and organization of phosphatidylcholine bilayers McMullen, T. P., R. N. Lewis, et al. (1994), Biophys J 66(3 Pt 1): 741-52. Abstract: We have investigated the comparative effects of the incorporation of increasing quantities of androstenol and cholesterol on the thermotropic phase behavior of aqueous dispersions of members of a homologous series of linear saturated diacyl PCs1 using high sensitivity DSC. We have also employed FTIR and 31P-NMR spectroscopy to study the comparative effects of androstenol and cholesterol incorporation on the organization of the host PC bilayer in both the gel and liquid-crystalline states. The effects of androstenol and cholesterol incorporation on the thermotropic phase behavior of shorter chain PCs like 14:0 PC are generally similar but not identical. The incorporation of either sterol progressively decreases the temperature and enthalpy, but not the cooperativity, of the pretransition and completely abolishes it at sterol concentrations above 5 mol%. Moreover, at sterol concentrations of 1 to 20-25 mol%, both androstenol and cholesterol incorporation produce DSC endotherms consisting of superimposed sharp and broad components, the former due to the hydrocarbon chain melting of sterol-poor and the latter to the melting of sterol-rich 14:0 PC domains. The temperature and cooperativity of the sharp component are reduced slightly with increasing concentration of androstenol or cholesterol, and the enthalpy of the sharp component decreases progressively and becomes zero at 20-25 mol% sterol. As well, at cholesterol or androstenol concentrations above 20-25 mol%, the enthalpy of the broad component also decreases linearly with increasing sterol incorporation and becomes zero at sterol levels of about 50 mol%. However, whereas cholesterol incorporation progressively increases the temperature of the broad component of the DSC endotherm, androstenol incorporation decreases the temperature of this component. In contrast, the effects of androstenol and cholesterol incorporation on the thermotropic phase behavior of the intermediate and longer chain PCs studied here are considerably different. Although the incorporation of cholesterol increases the main phase transition temperature of 16:0 PC slightly and decreases the phase transition of 18:0 PC and 21:0 PC, androstenol incorporation decreases the main phase transition temperatures of all three PCs rather markedly. Moreover, androstenol is less effective in reducing the enthalpy and cooperativity of the broad component of the DSC endotherm of 16:0 PC and especially 18:0 PC bilayers in comparison to cholesterol. Androstenol incorporation (> 5 mol%) also results in the appearance of a second, low temperature endotherm in the DSC traces of the intermediate and longer chain PC dispersions that is not observed in similar cholesterol/PC dispersions.(ABSTRACT TRUNCATED AT 400 WORDS) |
| Comparative effect of dietary sitosterol on plasma sterols and cholesterol and bile acid synthesis in a sitosterolemic homozygote and heterozygote subject Cobb, M. M., G. Salen, et al. (1997), J Am Coll Nutr 16(6): 605-13. Abstract: OBJECTIVE: Sitosterolemia is a genetic disorder characterized by an increased plasma plant sterol concentration due to enhanced sterol absorption coupled with reduced steroid excretion. The purpose of the present investigation was two-fold; first to assess the effects of a "basal" low sitosterol metabolic diet on plasma sterols and sterol balance, and, secondly, to quantify the relative influence of graduated increase in dietary sitosterol intake on a metabolic diet in a sitosterolemic homozygote, obligate heterozygote, and controls. METHODS: Patients were studied under strict metabolic conditions and fed a "basal" 30% fat, low-sitosterol (33 mg per 2000 kcal) diet. The level of dietary sitosterol was increased by addition of oils and resulted in final dietary sitosterol intakes of 1.8 mg/kg, 2.6 mg/kg and 3.5 mg/kg/day intakes of dietary sitosterol in the homozygote. These sitosterol dosages were selected based on sitosterol intakes equivalent to 2.6 mg/kg/day in the average American diet. Plasma cholesterol, sitosterol, and apolipoprotein A were measured, and stool collections assayed for sterol balance. RESULTS: Fecal sterol excretion and cholesterol synthesis were depressed markedly by 50% in the homozygote compared to the heterozygous parent, whereas plasma sitosterol levels were increased over 50-fold. When the sitosterol content of the diet was increased three-fold and dietary cholesterol was maintained in the homozygous and hypercholesterolemic control, plasma levels did not increase in the homozygote. Plasma cholesterol and sitosterol levels were unaffected in the hypercholesterolemic control. CONCLUSIONS: Plasma sterol levels remained elevated with the dietary sitosterol changes in the sitosterolemic homozygote. These findings were associated with a low fecal sterol excretion rate and depressed endogenous cholesterol synthesis. In this sitosterolemic patient, a very low sitosterol diet to curtail sterol input was of minimal therapeutic benefit. These results have important implications regarding the selection of therapy for this patient under these experimental conditions, but cannot be generalized to other homozygotes. |
| Comparative effects of cholesterol and cholesterol sulfate on hydration and ordering of dimyristoylphosphatidylcholine membranes Faure, C., J. F. Tranchant, et al. (1996), Biophys J 70(3): 1380-90. Abstract: The comparative effect of cholesterol (CH) versus cholesterol sulfate (CS) on dimyristoylphosphatidylcholine (DMPC) membranes has been investigated by optical microscopy, freeze-fracture electron microscopy, x-ray diffraction, and solid state 2H and 31P nuclear magnetic resonance (NMR). The sulfate analogue extends the lamellar phase domain toward high water contents, and substitution of 30 mol % CH by CS in DMPC lamellae induces the trapping of 30 wt % additional water. The greater swelling of the CS-containing systems is evidenced by determination of lamellar repeat distances at maximal hydration: 147 +/- 4 A and 64 +/- 2 A in the presence of CS and CH, respectively. 2H-NMR of heavy water demonstrates that CS binds approximately 12 more water molecules at the interface than CH whereas NMR of deuterium-labeled DMPC chains reveals that 30 mol % CS orders the membrane as 15 mol % CH at high temperature and disorders much more than CH at low temperatures. The various effects of CS versus CH are discussed by taking into account attractive Van der Waals forces and repulsive steric/electrostatic interactions of the negatively charged sulfate group. |
| Comparative effects of droloxifene, tamoxifen, and estrogen on bone, serum cholesterol, and uterine histology in the ovariectomized rat model Ke, H. Z., H. K. Chen, et al. (1997), Bone 20(1): 31-9. Abstract: The purpose of this study was to compare the effects of droloxifene (DRO), tamoxifen (TAM), and 17 alpha-ethynyl estradiol (EE) on bone mineral density, bone histomorphometry, total serum cholesterol, and uterine histology in the ovariectomized (ovx) rat model. Sprague-Dawley female rats at five months of age were sham-operated and treated orally with vehicle (n = 8), or ovx (n = 56) and treated (p.o.) with either vehicle, DRO at 0.1 or 1.0 mg/kg daily, TAM at 0.1 or 1 mg/kg daily, or EE at 3 or 30 micrograms/kg daily for 4 weeks. The uterine wet weight and uterine histologic parameters (cross-sectional tissue area, stromal thickness, and luminal epithelial thickness) were determined. Femoral and lumbar vertebral bone mineral density was determined ex vivo using dual energy x-ray absorptiometry. Static and dynamic cancellous bone histomorphometry was performed on double-labeled, undecalcified longitudinal sections from proximal tibial metaphyses. Furthermore, the changes in total serum cholesterol and body weight gain were also determined. Compared to sham controls, ovx for four weeks significantly decreased uterine weight (-72%), uterine cross-sectional tissue area (-74%), stromal thickness (-52%), and luminal epithelial thickness (-53%). ovx rats treated with EE at 30 micrograms/kg/day maintained these parameters at the levels of sham controls. Uterine weight and uterine cross-sectional tissue area in 3 micrograms/kg/day of EE treated ovx rats were higher than that of vehicle-treated ovx rats. In ovx rats treated with TAM at both 0.1 and 1 mg/kg/day, these parameters were significantly less than sham controls but significantly higher than ovx controls. DRO at 0.1 mg/kg/day had no effects on all above parameters. Uterine weight and cross-sectional tissue area in 1 mg/kg/day of DRO treated ovx rats was slightly but significantly higher than that in ovx controls. However, DRO at 1 mg/kg/day had no effects on uterine stromal thickness and luminal epithelial thickness compared to ovx controls. The ovx-induced decrease in femoral and lumbar vertebral bone mineral density was prevented by treatment with EE at 30 micrograms/kg/day, TAM at both 0.1 and 1 mg/kg/day, or DRO at 1 mg/kg/day. Similarly, the decrease in bone mass and the increase in bone resorption and bone turnover in proximal tibial metaphyses were prevented by treatment with EE at 30 micrograms/kg/day or TAM at both 0.1 and 1 mg/kg/day, or DRO at 1 mg/kg/day. Total serum cholesterol decreased significantly in ovx rats treated with either EE, DRO, or TAM at all dose levels compared to vehicle treated ovx controls (-32% to -56%). The ovx-induced body weight gain was completely prevented by EE at 30 micrograms/kg/day, and partially prevented by DRO at 1 mg/kg/day. TAM at both 0.1 and 1 mg doses caused a significant decrease in body weight compared to both sham and ovx controls. Our results indicated that DRO prevented ovx-induced bone loss and lowered total serum cholesterol with an ED50 less than 1 mg/kg/day. The bone protective and cholesterol lowering effects of DRO were comparable to those observed with TAM and EE. However, DRO differed from TAM and EE in its lack of significant estrogenic effects on uterine tissue at doses which were bone protective. These data suggest that DRO may be a significant alternative to EE and TAM for prevention and treatment of postmenopausal osteoporosis. |
| Comparative effects of flaxseed and sesame seed on vitamin E and cholesterol levels in rats Yamashita, K., S. Ikeda, et al. (2003), Lipids 38(12): 1249-55. Abstract: Flaxseed and sesame seed both contain more than 40% fat, about 20% protein, and vitamin E, mostly gamma-tocopherol. Furthermore, both contain considerable amounts of plant lignans. However, flaxseed contains 54% alpha-linolenic acid, but sesame seed only 0.6%, and the chemical structures of flaxseed and sesame lignans are different. In this study, we investigated the differential effects of flaxseed and sesame seed on plasma and tissue gamma-tocopherol, TBARS, and cholesterol concentrations. Rats were fed experimental diets for 4 wk: vitamin E-free, (-VE), gamma-tocopherol, flaxseed (FS), sesame seed (SS), flaxseed oil (FO), FO with sesamin (FOS), and defatted flaxseed (DFF). SS and FOS diets induced significantly higher gamma-tocopherol concentrations in plasma and liver compared with FS, FO, and DFF diets. Groups fed FS, FO, and FOS showed lower plasma total cholesterol compared with the SS and DFF groups. Higher TBARS concentrations in plasma and liver were observed in the FS and FO groups but not in the FOS group. These results suggest that sesame seed and its lignans induced higher gamma-tocopherol and lower TBARS concentrations, whereas flaxseed lignans had no such effects. Further, alpha-linolenic acid produced strong plasma cholesterol-lowering effects and higher TBARS concentrations. |
| Comparative effects of long-term continuous release of 16 alpha-hydroxyestrone and 17 beta-estradiol on bone, uterus, and serum cholesterol in ovariectomized adult rats Lotinun, S., K. C. Westerlind, et al. (2003), Bone 33(1): 124-31. Abstract: 16Alpha-hydroxyestrone (16alpha-OHE(1)), an endogenous estrogen metabolite, is associated with increased bone density in postmenopausal women. This study was designed to evaluate the long-term activity of this metabolite on bone, uterus, and serum cholesterol in an animal model for postmenopausal bone loss. A preliminary dose-response study performed in weanling rats determined 2000 microg/kg/day to be the optimal dose of 16alpha-OHE(1) for studying estrogenic effect on bone. The long-term experiment was performed in 6-month-old animals that were either sham-operated or OVX. The OVX rats were implanted sc with 60-day continuous-release carrier, 17beta-estradiol (E(2)) (33 microg/kg/day) or 16alpha-OHE(1) pellets (2000 microg/kg/day). OVX decreased uterine weight, increased body weight, serum cholesterol, and all dynamic bone histomorphometric measurements in cortical and cancellous bone, and resulted in a 54% bone loss at the tibial metaphysis. E(2) completely prevented OVX-induced bone loss, suppressed bone turnover, and induced uterine hypertrophy and hypercholesterolemia. 16alpha-OHE(1) acted as an E(2) agonist on bone, suppressing bone formation and resorption. However, the estrogen metabolite lowered serum cholesterol and was only a partial E(2) agonist on uterine weight and epithelial cell height. These results suggest that 16alpha-OHE(1) is an estrogen agonist on bone and may be responsible, in part, for the cholesterol-lowering activity attributed to estrogen. As a consequence of its skeletal effects, older women who produce high levels of 16alpha-OHE(1) could have a lower risk for developing postmenopausal osteoporosis than women who produce less-active estrogen metabolites. |
| Comparative effects of phytosterol oxides and cholesterol oxides in cultured macrophage-derived cell lines Adcox, C., L. Boyd, et al. (2001), J Agric Food Chem 49(4): 2090-5. Abstract: The cytotoxicity of cholesterol and a mixture of beta-sitosterol/campesterol (50%/40%) and their oxides was examined in a cultured-derived macrophage cell line, C57BL/6. Cell numbers, lactate dehydrogenase (LDH) leakage, protein content, lipid uptake, and mitochondria dehydrogenase activity were determined after exposure of cell mononlayers to sterols and sterol oxides at a concentration of 200 microg/mL for up to 120 h. Results indicate that the oxides of cholesterol, beta-sitosterol, and campesterol exhibited similar patterns of toxicity as indicated by LDH leakage, cell viability, and mitochondria dehydrogenase activity. Greatest cell damage was associated with treatments containing 5 alpha,6 alpha-epoxide or cholesterol oxides, followed by beta-sitosterol/campesterol oxides, cholesterol, and beta-sitosterol. The oxides of beta-sitosterol/campesterol caused less LDH leakage and less of an effect on protein content. Results of this study demonstrate that phytosterols contained in vegetable oils, when subjected to frying conditions, do oxidize and may cause cellular damage in an in vitro cell line similar to cholesterol oxides, although less severe. |
| Comparative effects of simvastatin (MK-733) and pravastatin (CS-514) on hypercholesterolemia induced by cholesterol feeding in rabbits Ishida, F., K. Watanabe, et al. (1990), Biochim Biophys Acta 1042(3): 365-73. Abstract: The preventive effects of simvastatin (MK-733) and pravastatin (CS-514), 3-hydroxy-3-methylglutarylcoenzyme A (HMG-CoA) reductase inhibitors, on hypercholesterolemia induced by 0.25% cholesterol feeding were compared in rabbits. MK-733 (6, 2 and 0.7 mg/kg) was found to prevent the increase in serum total cholesterol levels dose-dependently. High dose CS-514 (18 mg/kg) also limited the increase in the cholesterol levels, but medium (6 mg/kg) and low doses (2 mg/kg) of CS-514 were ineffective in preventing it. MK-733 inhibited the increase in VLDL and LDL cholesterol levels dose-dependently. MK-733 suppressed the increase in serum phospholipid levels. MK-733 inhibited the accumulation of cholesterol in the liver. The high dose of CS-514 also limited it. High dose MK-733 (6 mg/kg) reduced the cholesterol concentration in gallbladder bile. Neither MK-733 nor CS-514 affected bile acid excretion in the gallbladder bile. High dose MK-733 decreased the lithogenic index. MK-733 increased the number of LDL receptors, and high dose CS-514 also increased it. The suppressive effect of CS-514 on serum cholesterol levels at 18 mg/kg was found to be less than that of MK-733 at 0.7 mg/kg. |