| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| A single daily dose of soybean phytosterols in ground beef decreases serum total cholesterol and LDL cholesterol in young, mildly hypercholesterolemic men Matvienko, O. A., D. S. Lewis, et al. (2002), Am J Clin Nutr 76(1): 57-64. Abstract: BACKGROUND: Consumption of phytosterol-supplemented margarine lowers total plasma cholesterol (TC) and LDL-cholesterol concentrations in older middle-aged hypercholesterolemic individuals. The effects of incorporating phytosterols into lower-fat foods on the plasma lipids of young men at increased risk of developing cardiovascular disease have not been studied. OBJECTIVE: We tested the hypothesis that a single daily dose of soybean phytosterols added to ground beef will lower plasma TC and LDL-cholesterol concentrations in mildly hypercholesterolemic young men. DESIGN: In a triple-blind, 4-wk study, 34 male college students with elevated plasma TC (5.85 +/- 0.70 mmol/L), LDL cholesterol (4.02 +/- 0.60 mmol/L), and TC:HDL cholesterol (5.5 +/- 1.2) were randomly assigned to the control (ground beef alone) or treatment (ground beef with 2.7 g of phytosterols) group. The phytosterol mixture was two-thirds esterified and one-third nonesterified and consisted of beta-sitosterol (48%), campesterol (27%), and stigmasterol (21%). RESULTS: Consumption of phytosterol-supplemented ground beef lowered plasma TC and LDL-cholesterol concentrations and TC:HDL cholesterol from baseline by 9.3%, 14.6%, and 9.1%, respectively (P < 0.001). The LDL particle size did not change, suggesting that the decrease was primarily of particle number. The decreases were similar in subjects with (n = 8) and without (n = 9) a family history of premature cardiovascular disease. No significant changes were found in the control group. CONCLUSION: Phytosterol-supplemented ground beef effectively lowers plasma TC and LDL cholesterol and has the potential to become a functional food to help reduce the risk of cardiovascular disease. |
| A single point mutation controls the cholesterol dependence of Semliki Forest virus entry and exit Vashishtha, M., T. Phalen, et al. (1998), J Cell Biol 140(1): 91-9. Abstract: Membrane fusion and budding are key steps in the life cycle of all enveloped viruses. Semliki Forest virus (SFV) is an enveloped alphavirus that requires cellular membrane cholesterol for both membrane fusion and efficient exit of progeny virus from infected cells. We selected an SFV mutant, srf-3, that was strikingly independent of cholesterol for growth. This phenotype was conferred by a single amino acid change in the E1 spike protein subunit, proline 226 to serine, that increased the cholesterol independence of both srf-3 fusion and exit. The srf-3 mutant emphasizes the relationship between the role of cholesterol in membrane fusion and virus exit, and most significantly, identifies a novel spike protein region involved in the virus cholesterol requirement. |
| A single-centre retrospective observational study to evaluate the change in total cholesterol and LDL cholesterol in hyperlipidaemic patients switched from atorvastatin to simvastatin Raal, F. J. (2004), Cardiovasc J S Afr 15(3): 118-23. Abstract: The clinical effects of switching from one HMG Co-A reductase inhibitor (atorvastatin) to another therapeutic agent within the same class (simvastatin) were examined in this observational study. Levels of total-C, LDL-C, HDL-C and triglycerides from 100 patients were compared before and after switching, and the maintenance, improvement or loss of lipid control was assessed. There was a significant increase in total-C and triglycerides (p < 0.05) following the switch from atorvastatin to simvastatin. A number of patients showed > or = 10% variation in lipid levels after switching. The high intrapatient variation seen in this study strongly suggests that therapeutic substitution is associated with an unpredictable response in plasma lipid levels and their control. This would have practical implications for physicians who are considering a switch of this nature. |
| A sol-gel method using acetic anhydride in the presence of cholesterol in organic solution media: preparation of silicas that recognize steroid hormones Fujiwara, M., M. Nishiyama, et al. (2004), Anal Chem 76(8): 2374-81. Abstract: Silicas were prepared by a sol-gel method from tetraethoxysilane and acetic anhydride in the presence of cholesterol in organic solution media. Some silicas had higher pore volumes than silicas obtained in the absence of cholesterol. The adsorption abilities by these silicas were compared using various compounds in benzene solution. Although no clear difference among their adsorptions of cholesterol was observed, progesterone and other analogous steroid hormones were well adsorbed by silicas prepared in the presence of cholesterol, especially, prepared with n-heptane as an additional solvent. This silica adsorbed steroid hormones more selectively than other analogous compounds such as bisphenol A and hexestrol. On the other hand, a silica prepared by the usual aqueous sol-gel method with cholesterol had no clear adsorption selectivity to steroid hormones. Furthermore, no selective adsorption of steroid hormones was observed in the case of a common silica gel for column chromatography. This unique property of adsorption observed in silicas prepared using acetic anhydride in the presence of cholesterol is likely to be induced by the imprinting effect of the steroid skeleton part of cholesterol in silica matrix. |
| A solid-state NMR study of phospholipid-cholesterol interactions: sphingomyelin-cholesterol binary systems Guo, W., V. Kurze, et al. (2002), Biophys J 83(3): 1465-78. Abstract: We used solid-state NMR techniques to probe the interactions of cholesterol (Chol) with bovine brain sphingomyelin (SM) and for comparison of the interactions of Chol with dipalmitoylphosphatidylcholine (DPPC), which has a similar gel-to-liquid crystalline transition temperature. (1)H-, (31)P-, and (13)C-MASNMR yielded high-resolution spectra from multilamellar dispersions of unlabeled brain SM and Chol for analysis of chemical shifts and linewidths. In addition, (2)H-NMR spectra of oriented lipid membranes with specific deuterium labels gave information about membrane ordering and mobility. Chol disrupted the gel-phase of pure SM and increased acyl chain ordering in the liquid crystalline phase. As inferred from (13)C chemical shifts, the boundaries between the ordered and disordered liquid crystalline phases (L and L) were similar for SM and DPPC. The solubility limit of Chol in SM was ~50 mol %, the same value as previously reported for DPPC membranes. We found no evidence for specific H-bonding between Chol and the amide group of SM. The order parameters of a probe molecule, d31-sn1-DPPC, in SM were slightly higher than in DPPC for all carbons except the terminal groups at 30 mol % but were not significantly different at 5 and 60 mol % Chol. These studies show a general similarity with some subtle differences in the way Chol interacts with DPPC and SM. In the environment of a typical biomembrane, the higher proportion of saturated fatty acyl chains in SM compared to other phospholipids may be the most significant factor influencing interactions with Chol. |
| A spread enriched with plant sterol-esters lowers blood cholesterol and lipoproteins without affecting vitamins A and E in normal and hypercholesterolemic Japanese men and women Ntanios, F. Y., Y. Homma, et al. (2002), J Nutr 132(12): 3650-5. Abstract: The objective of the study was to investigate whether different initial baseline cholesterol levels modulate the efficacy of a spread enriched with plant sterol-esters (PS) in lowering blood cholesterol in a Japanese population consuming their usual diet. Healthy adults with a mean age of 45 y and mean plasma total cholesterol (TC) level of 6.5 mmol/L were recruited to participate in a double-blind trial comprised of a run-in period of 1 wk, followed by two intervention periods of 3 wks in a 2 x 2 crossover design and a post-trial follow-up of 3 wk. Volunteers consumed two spreads, one enriched with PS (12 g/100 g plant sterols) and a control spread not fortified with PS. Recommended spread intake was 15 g/d. Effects on plasma lipids, lipoproteins, beta-carotene and vitamins A and E were assessed. Plasma TC and LDL cholesterol (LDL-C) concentrations were 5.8 and 9.1% lower, respectively, when subjects consumed the PS spread than when they consumed the control spread (P < 0.001). Subjects were divided into two groups normal and mildly cholesterolemic (TC <5.7 mmol/L) and hypercholesterolemic (TC >/= 5.7 mmol/L). Reductions (P < 0.001) in TC and LDL-C due to treatment in the former group were 4.9 and 7.9%, respectively. In the hypercholesterolemic group, the reductions (P < 0.001) were 7.1 and 10.6%, respectively. The decreases did not differ between normal/mildly cholesterolemic and hypercholesterolemic subjects. Plasma apolipoprotein B (apoB) and remnant-like particle (RLP) cholesterol (RLP-C) concentrations were lower when subjects consumed the PS spread (44.3 g/L) than the control spread (49.7 g/L). Plasma beta-carotene concentration was lower (P < 0.001) in subjects consuming the PS spread than in the control. Changes in plasma vitamins A and E levels did not differ after intake of the PS and control spreads. In conclusion, consumption of a PS-enriched spread effectively lowered plasma TC, LDL-C, apoB and RLP-C regardless of baseline plasma TC at an intake of 1.8 g/d of plant sterols. |
| A study about the effect of vitamin E on hyperlipidemia and atherosclerotic lesions in New Zealand white rabbits fed with a 1% cholesterol rich diet Torres, M., M. Marquez, et al. (2003), Invest Clin 44(2): 119-27. Abstract: The purpose of this study was to determine whether the administration of Vitamin E (200 mg/day) for 4 weeks could decrease hypercholesterolemia and inhibit atherosclerosis in male hypercholesterolemic New Zealand White rabbits. Plasmatic Total Cholesterol (TC) and LDL-Cholesterol (LDLc) were determined by enzymatic methods and Vitamin E was determined in plasma by HPLC at weeks 0, 4 and 8. A histopathological study was carried out at week 8 (w 8), using a hematoxylin-eosin method. Forty rabbits were divided randomly into 5 groups and fed different diets. These diets included a Normal diet, a 1% Cholesterol rich diet, a Normal diet + Vitamin E and 1% Cholesterol rich diet + Vitamin E. The findings did not show a reduction of Total Cholesterol and LDLc in the groups of rabbits that received Vitamin E (III and IV) at weeks 4 and 8. At the end of the experiment, all the animals were deeply anesthetized with hydrochloride ketamina (60 mg/kg body wt) in order to carry out a histopathological study. Regarding the atherosclerotic lesions, Vitamin E did not induce inhibition of the atherosclerotic plaque development or any modification in the lesion type induced by the hypercholesterolemic diet. In conclusion, the results suggest that additional studies need to be carried out with higher doses and/or treatments for a longer period in order to clarify in detail whether Vitamin E really has a hypocholesterolemic effect and inhibits atherosclerosis. |
| A study of dietary cholesterol induced changes in serum lipid lipoproteins in healthy male children, adolescents and middle aged volunteers Arora, R. C., R. K. Garg, et al. (1990), Indian Pediatr 27(10): 1067-71. Abstract: The present study comprised of 16 healthy male subjects of 8-12 years (Group A), 18 adolescent males (13-19 years) (Group B) and 20 middle aged volunteers (45-55 years) (Group C), who were fed a high cholesterol high fat diet (HCFD) consecutively for seven days. The serum lipid changes were noted. The diet was then withdrawn. Seven days later the lipid changes were again recorded. At basal stage, serum total cholesterol (STC), high density lipoprotein (HDL) and low density lipoprotein (LDL) were significantly higher in group C in comparison to Group A. LDL/HDL ratio was significantly lower in Group C than that of Group A. Seven days after feeding of HCFD significant elevations occurred in all the lipid subfractions of Groups AB. The rise in STC was mainly because of predominant rise in HDL leading to a significant fall in LDL/HDL ratio. In Group C, elevations occurred in all the lipid fractions except HDL that showed an insignificant rise. LDL/HDL ratio was insignificantly affected. After withdrawal of HCFD, all the lipid levels returned to normal except in Group A, where STC and LDL remained elevated. The LDL/HDL ratio again increased significantly. In conclusion, the serum lipid lipoprotein behaviour in response to HCFD is qualitatively different in young persons as compared to middle aged persons. |
| A study of high fat and cholesterol induced lipoprotein changes in first degree relatives of patients of myocardial infarction Arora, R. C., N. Agarwal, et al. (1991), Mater Med Pol 23(3): 200-2. Abstract: The effect of seven days feeding of high cholesterol and high fat breakfast (HCFB) (79.5 g fat, 1655 mg cholesterol) and its withdrawal was studied on 20 first degree relatives of patients of myocardial infarction (Group A) and 18 controls (Group B). All subjects were young (30 years of age) and had no other risk factor for ischaemic heart disease (IHD). At basal level the first degree relatives had significantly lower values for all lipid fractions except that of HDL. In the control group seven days after giving HCFB a significant rise occurred in all lipid fractions except LDL. The rise of HDL was dominant which led to a significant reduction in LDL/HDL ratio. However, in the first degree relatives no significant change could be observed in any lipid fraction. Seven days after the withdrawal of HCFB there was a significant reduction in all lipid fractions in controls but in first degree relatives the cholesterol level increased significantly from its basal value. However, other lipid fractions showed no significant change, and LDL/HDL ratio remained constant throughout. These different types of behavioural responses to cholesterol could be helpful in identifying high risk hereditarily predisposed persons at early age when basal lipid values are inconclusive. |
| A study of short term lipoprotein changes induced by single high cholesterol diet in healthy and diseases human volunteers Arora, R. C., N. Agarwal, et al. (1991), Mater Med Pol 23(4): 299-301. Abstract: Changes in lipid lipoprotein profile were observed in the first and third hours after feeding 750 mg of egg cholesterol in 13 healthy male subjects (Group A), 6 patients of coronary artery disease (Group B), 10 diabetic patients (Group C), and 10 hypertensive patients (Group D), all belonging to the age group of 35-60 years. 61.53% of healthy male subjects showed a fall in the total serum cholesterol (STC) in the first hour after feeding, while in the rest there was a rise. On the other hand, 66.67% of coronary artery disease patients, 50% of diabetics and 50% hypertensives showed a rise in the first hour while the rest showed either a fall or no change in STC. All groups showed a fall in LDL at the first hour. In the third hour the STC and LDL level increased in group A, C and D, whereas in group B STC showed a fall and LDL showed a rise. All these changes were, however, statistically insignificant. The changes in HDL values were also statistically insignificant except in group D where they showed a progressive rise increase in the first and third hours. |
| A study of the correlation between serum total cholesterol and low-density lipoproteins (LDL) in Chinese Lam, C. L., C. Munro, et al. (1990), Fam Pract 7(4): 301-6. Abstract: Serum total cholesterol and lipoprotein analysis was performed on the same blood samples of 139 asymptomatic Chinese subjects aged 40-60 years. There was a highly significant correlation between serum total cholesterol and low density lipoproteins (correlation coefficient = 0.8376, p less than 0.001) in Chinese, which means that total cholesterol can be used as the initial screening to identify individuals who may need lipoprotein analysis. The American National Cholesterol Education Programme (ANCEP) recommended threshold total cholesterol levels that indicate lipoprotein analysis for the high risk and low risk groups were found to have high sensitivities and negative predictive values but relatively low specificities and positive predictive values. Thirty to forty per cent of the lipoprotein analyses recommended by the ANCEP guidelines were not necessary. There was no significant age or sex influence on the degree of correlation between serum total cholesterol and LDL. |
| A study of the impact of Arabic coffee consumption on serum cholesterol el Shabrawy Ali, M. and F. M. Felimban (1993), J R Soc Health 113(6): 288-91. Abstract: Consumption of Arabic coffee is commonly practised by Saudi citizens. The present study was conducted to explore the possible relationship between the serum total cholesterol levels and the intake of Arabic coffee. A total of 252 adult Saudi individuals were recruited, of whom 143 were coffee drinkers and 109 did not drink coffee. The study showed that in comparison to the non-coffee drinkers the serum total cholesterol concentration was significantly higher among the coffee drinkers. Furthermore, the level was higher among females than males who were coffee drinkers. The effect of the duration of coffee consumption on the serum total was significant for both sexes (P < 0.001). It is suggested that further studies should be generated in order to address questions related to the issues discussed. At the present time a reduction in coffee consumption by those groups found to be more liable to adverse influence on their serum total cholesterol levels to have a positive influence should be considered. |
| A study of the phase transition behaviours of cholesterol and saturated egg lecithin, and their interaction by differential scanning calorimetry Khan, M. Z. and I. G. Tucker (1992), Chem Pharm Bull (Tokyo) 40(11): 3056-61. Abstract: The thermal behaviours of hydrogenated egg lecithin (PC) and cholesterol (C) in anhydrous form and in aqueous dispersions were studied by differential scanning calorimetry. The role of C in phase transitions of C-PC mixtures prepared by physical mixing or coprecipitating from chloroform has been examined. C underwent a phase transition at 34 degrees C and a second one at 76-78 degrees C which depended on the thermal history of the samples. C lowered the gel to liquid crystalline phase transition temperature (Tt) of the aqueous dispersions prepared from C-PC coprecipitates, broadened the endothermic peak at the Tt, and at 1:1 molar ratio the C-PC system did not undergo the phase transition. The C-PC interaction was observed below the Tt. In aqueous dispersions prepared from C-PC physical mixtures, C did not influence the phase transition and acted like an inert diluent. Pellets prepared from C-PC mixtures formed myelin bodies as a result of their erosion in 0.185 M borate buffer (pH 7.4) at below Tt, but the thermal behaviours of these myelin bodies were different for pellets prepared differently. Addition of bovine serum albumin (BSA) (10%, w/w) to the physical mixtures or coprecipitates of C-PC, or to PC alone did not show any effect on the thermal behaviours of their aqueous dispersions at the Tt. |
| A study of the temporal effect of alcohol on human erythrocyte sodium-lithium countertransport in relation to membrane cholesterol and phospholipids Adebayo, G. I., P. Gaffney, et al. (1996), Alcohol 13(6): 597-602. Abstract: The effect of a single dose of alcohol (0.8 g/kg), given with "diet coke," on erythrocyte sodium-lithium countertransport (SLC) in relation to membrane cholesterol and phospholipids was assessed over 24 h in 10 healthy volunteers. Baseline passive lithium efflux (0.168 +/- 0.008 mmol l-1 Cell H-1) was increased 1 h (0.202 +/- 0.014 mmol l-1 cell h-1; p < 0.030), and 4 h (0.200 +/- 0.014 mmol l-1 cell h-1; p < 0.020), but similar to that at 24 h postalcohol (0.173 +/- 0.011 mmol l-1 cell h-1). These changes were not associated with any change in intracellular lithium. Control SLC VMAX of 0.387 +/- 0.054 mmol l-1 cell h-1 fell at 1 h (0.328 +/- 0.050 mmol l-1 cell h-1; p = 0.0012) and 4 h (0.312 +/- 0.048 mmol l-1 cell h-1; p < 0.0005). Its value 24 h postalcohol (0.371 +/- 0.047 mmol l-1 cell h-1) was comparable to that at baseline. There was no significant change in the affinity of the transporter for external sodium throughout the experimental period, suggesting that the reduction in VMAX 1 and 4 h after alcohol ingestion resulted from a noncompetitive inhibition. Intracellular sodium 4 h after alcohol was lower than at baseline, but returned to the control value within 24 h. In a control group (n = 5), pretreatment with "diet coke" alone did not alter any of the measured parameters. It is concluded that alcohol pretreatment increases passive lithium efflux and decreases SLC Vmax. Both effects are evident up to at least 4 h postdosing, but recover within 24 h in the absence of further alcohol intake. |
| A study on cholesterol content in some tissues of the Saudi frog: Rana ridibunda Alyousif, M. S. (1991), Comp Biochem Physiol A 100(1): 133-4. Abstract: 1. Cholesterol content of selected tissues in the Saudi frog Rana ridibunda was determined. 2. Total cholesterol content was higher in tissues involved in water loss, ranging from 12.22 +/- 0.28 to 40.3 +/- 0.79 mg/g. 3. In tissues not involved in water loss, total cholesterol content ranged from 2.42 +/- 0.18 to 19.30 +/- 0.39 mg/g. |
| A study on lipid metabolism in heart and liver of cholesterol- and pectin-fed rats Hexeberg, S., E. Hexeberg, et al. (1994), Br J Nutr 71(2): 181-92. Abstract: Pectin is known as a cholesterol-reducing dietary fibre, and in the present study we addressed the question whether pectin affected the quantity of lipid in droplets in the myocardial cells and of lipid in the liver cells. Male Wistar rats received either a diet containing cholesterol or a standard diet without cholesterol with 0, 50 or 100 g pectin/kg incorporated for 10 d. The fractional volume of lipid droplets in the myocardial cells decreased as a function of pectin dose in both the standard-fed and the cholesterol-fed rats. Serum cholesterol was significantly reduced in both groups after addition of 100 g pectin/kg diet. The cholesterol diet increased the liver cholesterol level, and 100 g pectin/kg diet resulted in a lower concentration of liver cholesterol in the cholesterol-fed animals, but the influence on standard-fed rats was modest. Hydroxymethylglutaryl-CoA reductase (EC 1.1.1.88; HMG-CoA reductase) activity increased when pectin was given in the standard diet. Liver triacylglycerol level increased after cholesterol and pectin feeding. Mitochondrial fatty acid oxidation and phosphatidate phosphohydrolase (EC 3.1.3.4) activity tended to decrease, whereas the peroxisomal fatty acid oxidation and acyl-CoA oxidase activity were unchanged. Increased hepatic triacylglycerol content by cholesterol and pectin treatment may be due to inhibited mitochondrial fatty acid oxidation along with increased availability of fatty acid for esterification and triacylglycerol synthesis. The presence of pectin in the diets of cholesterol-fed rats resulted in increased hepatic concentration of triacylglycerols and increased mitochondrial fatty acid oxidation. In this case the hepatic accumulation of triacylglycerol may be mediated by a reduced efflux of triacylglycerols from the liver. |
| A study on physiological changes in essential hypertension and rheumatoid arthritis with reference to the levels of cortisol, blood glucose, triglycerides and cholesterol Mishra, K. K. and H. P. Pandey (1995), Indian J Physiol Pharmacol 39(1): 68-70. Abstract: The levels of plasma cortisol, blood glucose, serum triglycerides (TG) and total cholesterol (TC) were estimated in 175 human subjects (50 normal controls, 65 having essential hypertension and 60 suffering from rheumatoid arthritis. The results showed a significant elevation in the levels of plasma cortisol and blood glucose in both the stressed clinical groups with respect to controls. Increased levels of atherogenic lipids (TG and TC) were also observed in diseased group. However, in rheumatoid arthritis the biochemical changes were comparatively more pronounced than in hypertensives. The findings in vitro reveal that rheumatoid arthritis is a relatively more chronic and late onset disorder, since the functional performance of hypothalamo-pituitary-adrenocortical (HPA) axis declines with chronicity and the efficacy of adrenocortical response to return to normalcy becomes impaired. |
| A study on serum triglyceride and lipoproteins cholesterol in coronary heart disease patients Awan, Z. A. and A. Baseer (1995), J Pak Med Assoc 45(10): 263-6. Abstract: Sera obtained from 42 patients of myocardial infarction, 28 of unstable angina and 25 healthy control subjects was assayed for total triglycerides, cholesterol, LDL cholesterol (LDL-C), HDL Cholesterol (HDL-C) and VLDL Cholesterol (VLDL-C). The level of cholesterol was also determined among the sub-fractions of HDL. The levels of total triglycerides, cholesterol, LDL-C and VLDL-C were significantly raised in both groups of patients. Total high density lipoprotein cholesterol was low in patients, which was highly significant in HDL2-C and not in HDL3-C. These results suggest that serum lipids are directly correlated with the severity of coronary heart disease (CHD). Total cholesterol when measured in major lipoprotein classes and further partitioned into subfractions, increase their sensitivity, specificity and hence their predictive value as sensitive markers for the assessment of CHD risk. |
| A study on the influence of bile acid chemical structure on dissolution of insoluble calcium salts: an in vitro study of the use of bile acid-phosphatidylcholine-cholesterol model bile solution Yoneda, M., N. Tamasawa, et al. (1990), Gastroenterol Jpn 25(3): 383-7. Abstract: The influence of bile acid chemical structure on dissolution of insoluble calcium salts and the reducing effect of ionized calcium was studied. Various bile acids were used to compound model bile acid-phosphatidylcholine-cholesterol model bile solutions. After CaCO3 was added to these solutions, both total calcium solubility and ionized calcium concentration in the solutions were measured. Dihydroxy bile acid is more effective than trihydroxy bile acid and 7 alpha-hydroxy bile acid is more effective than 7 beta-hydroxy bile acid, with regard to calcium solubility and the reducing effect of ionized calcium in model bile solution. Glutamic or asparaginic acid conjugates are more effective than glycine or taurine conjugates. Therefore, calcium solubility and the reducing effect of ionized calcium in model bile solutions are dependent on the number and orientation of hydroxy groups on the steroid nucleus as well as electrical charge of conjugating amino acid of bile acid. Chenodeoxycholic acid conjugated with glutamic or asparginic acid possesses high calcium solubility and large binding capacity with ionized calcium. |
| A study on the mechanisms whereby apolipoprotein A-1 (apo A-1) inhibits cholesterol crystal nucleation in human gallbladder bile Tazuma, S., S. Mizuno, et al. (1991), Nippon Shokakibyo Gakkai Zasshi 88(4): 1083-8. Abstract: The aim of the present study was to determine the mechanisms whereby apo A-1 retards cholesterol crystal nucleation in human gallbladder bile. Ten human gallbladder bile samples were sterilely collected from patients with gallstones at surgery, subsequently applied on gel permeation chromatography to separate various lipid particles. A non-micellar fraction coeluted with apo A-1 was ultrastructurally characterized by transmission electron microscopy (TEM). As results, that fraction containing very little or no apo A-1, 400-600 A in diameter, showed rapid transformation, i.e. rouleau formation, multilamellar formation and consequently microcrystal formation, whereas those rich in apo A-1, 200-400 A in diameter, showed very little transformation for 7 days. Those data indicated that apo A-1 stabilizes non micellar fraction by forming an apo A-1 and lipid complexed particle, resulting in prolonged cholesterol crystal nucleation. |