| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
| First Page | Previous Page | Next Page | Last Page |
| Influence of analytical quality and preanalytical variations on measurements of cholesterol in screening programmes Petersen, H., M. L. Larsen, et al. (1990), Scand J Clin Lab Invest Suppl 198: 66-72. Abstract: In screening programmes one should distinguish between the traditional bimodal distributions of results and a unimodal distribution as the basis for interpretation. A model for evaluation of the effects of biological within-subject and preanalytical variation as well as analytical variation is described. It is concluded that bias from blood sampling and analytical performance influences the outcome of screening programs significantly. At least three blood specimens are needed for estimating the homeostatic set point of cholesterol in individuals. |
| Influence of anti-LDL receptor antibody on the transfer of cholesterol from LDL to isolated lymphocytes in normal subjects Iwata, S., N. Sakuma, et al. (1995), Clin Biochem 28(3): 309-11. |
| Influence of apolipoprotein E genotype on the reliability of the Friedewald formula in the estimation of low-density lipoprotein cholesterol concentrations Tremblay, A. J., J. Bergeron, et al. (2005), Metabolism 54(8): 1014-9. Abstract: Lipoprotein data and apolipoprotein (apo) E genotype from 1302 participants, covering a wide range of total plasma cholesterol levels, were used to examine the impact of apo E genotype on the estimation of low-density lipoprotein cholesterol (LDL-C0 concentrations by the Friedewald formula using high-density lipoprotein cholesterol and triglyceride (TG) concentrations as compared with the beta -quantification reference procedure. The results showed that participants with apo E2/E2 genotype had significantly higher very low-density lipoprotein cholesterol (VLDL-C) concentrations and VLDL-C/TG ratio as well as lower LDL-C concentrations than participants with other apo E genotypes. Heterozygous carriers of the varepsilon 2 allele had significantly higher VLDL-C than participants with apo E3/E3 and E4/E3 genotypes. The mean absolute error and the mean percentage of bias in calculated LDL-C according to all apo E genotypes, except E2/E2 genotype, were less than 0.16 mmol/L and 4.4%, respectively. Indeed, the mean error and the mean percentage of bias associated with the LDL-C calculated by the Friedewald formula in the apo E2/E2 group were 0.93 mmol/L and 40.6%, respectively. However, participants with the apo E2/E2 genotype and a type III phenotype showed a mean error and a mean percentage of bias reaching 1.53 mmol/L and 63.5%, respectively, whereas E2/E2 participants with a non-type III phenotype had a mean error and a mean percentage of bias of 0.18 mmol/L and 11.0%, respectively. Moreover, 41.9% to 57.1% of the participants had an absolute bias higher than 5% according to the apo E genotype, except for the apo E2/E2 genotypic group where 88.6% of the participants had an absolute bias higher than 5%. Stepwise multiple linear regression analyses revealed that the apo E genotype contributed to 39.0% of the VLDL-C/TG ratio variance, whereas sex, age, and high-density lipoprotein cholesterol explained between 0.5% and 3.2% of the variance. These results indicate that the apo E genotype exerts a significant influence on the estimation of LDL-C concentrations by the Friedewald formula as compared with the beta-quantification. |
| Influence of apolipoprotein E phenotypes on total serum cholesterol in Japanese children Tozuka, M., H. Ohta, et al. (1996), Clin Chim Acta 247(1-2): 175-80. |
| Influence of apolipoproteins AI, AII, and Cs on the metabolism of membrane and lysosomal cholesterol in macrophages Mahlberg, F. H., J. M. Glick, et al. (1991), J Biol Chem 266(30): 19930-7. Abstract: We have demonstrated previously that HDL-mediated efflux of plasma membrane cholesterol is independent of specific binding of apolipoproteins to the high density lipoprotein (HDL) receptor in either control or cholesterol-enriched cells (Karlin, J. B., Johnson, W. J., Benedict, C. R., Chacko, G. K., Phillips, M. C., and Rothblat, G. H. (1987) J. Biol. Chem. 262, 12557-12564 and Johnson, W. J., Mahlberg, F. H., Chacko, G. K., Phillips, M. C., and Rothblat, G. H. (1988) J. Biol. Chem. 263, 14099-14106). The present studies were conducted to determine if the process for removal of intracellular (lysosomal) cholesterol is similar to that of membrane cholesterol or if, in contrast, it is selectively regulated by specific apolipoproteins of HDL. For these reasons, we examined the influence of each of the major apolipoproteins of human HDL, apoAI, apoAII, and apoCs on the metabolism of membrane and lysosomal cholesterol in a macrophage foam cell model. We developed an experimental system which allows, for the first time, the simultaneous determination of lysosomal hydrolysis of cholesteryl ester and efflux and esterification of both lysosomal and membrane cholesterol. J774 and elicited mouse peritoneal macrophages were loaded with cholesteryl ester within lysosomes through phagocytosis of sonicated lipid droplets. Membrane and lysosomal pools of cholesterol were differentially radiolabeled. Discoidal complexes of egg phosphatidylcholine and purified apolipoproteins having a similar size and composition were used as cholesterol acceptors. Our results demonstrate that lysosomal hydrolysis of cholesteryl ester is independent of the presence of extracellular acceptors. Lysosomal production of cholesterol stimulates the esterification by acyl-CoA:cholesterol acyltransferase of membrane and lysosomal cholesterol. All the particles tested induce the efflux of both pools of cholesterol at a similar ratio. As efflux is stimulated, esterification by acyl-CoA:cholesterol acyltransferase is reduced. We conclude that none of these apolipoproteins selectively influences the efflux or the esterification of membrane of lysosomal cholesterol. In addition, we observe that particles containing apoAI are the most efficient acceptors, but this effect is not linked to specific binding to the HDL receptor. |
| Influence of baseline lipids on effectiveness of pravastatin in the CARE Trial. Cholesterol And Recurrent Events Pfeffer, M. A., F. M. Sacks, et al. (1999), J Am Coll Cardiol 33(1): 125-30. Abstract: OBJECTIVES: We sought to assess the influence of baseline lipid levels on coronary event rates and the effectiveness of pravastatin therapy in the Cholesterol And Recurrent Events (CARE) study. BACKGROUND: The CARE study cohort provided a relatively unique opportunity to examine the relation between lipid levels and clinical events in a post-myocardial infarction (MI) population with relatively low cholesterol and low density lipoprotein (LDL) cholesterol values. METHODS: There were 4,159 patients with a previous infarct and a total cholesterol level <240 mg/dl, LDL cholesterol level 115 to 174 mg/dl and triglyceride level <350 mg/dl randomly allocated to placebo (n=2,078) or pravastatin 40 mg/day (n=2,081). Time to either coronary death or nonfatal MI (primary end point) or to the secondary end point, which included undergoing a coronary revascularization procedure, was determined as a function of baseline lipids (total, LDL, high density lipoprotein HDL cholesterol and triglyceride levels). RESULTS: Quartile analysis indicated important effects for LDL cholesterol, in which a higher LDL was associated with greater cardiac event rates (in the placebo group, every 25-mg/dl increment in LDL was associated with a 28% increased risk 5% to 56%, p=0.015) in the primary event. The differential event rates with respect to baseline LDL cholesterol for placebo and pravastatin groups reduced the difference in clinical outcomes at lower LDL cholesterol levels. In both the placebo and pravastatin groups, an inverse relation between baseline HDL cholesterol and cardiac events was observed (10 mg/dl lower baseline HDL cholesterol level was associated with a 10% 0% to 19%, p=0.046 increase in coronary death or nonfatal MI). CONCLUSIONS: Within the LDL cholesterol levels in CARE (115 to 174 mg/dl), baseline values influenced both the risk of events in the placebo group as well as the clinical effectiveness of pravastatin therapy. |
| Influence of baseline values. I: Effects on plasma total cholesterol and triglyceride levels during doxazosin treatment for hypertension Ahaneku, J. E., G. O. Taylor, et al. (1998), Int J Clin Pharmacol Res 18(4): 159-63. Abstract: Forty-six African patients with essential hypertension aged 40 to 65 years had plasma total cholesterol and triglyceride levels determined at four different periods during a 12-month treatment with doxazosin. The patients were classified according to their pretreatment (baseline) values into 'low', 'medium' and 'high' baseline value groups. The mean total cholesterol levels significantly decreased in the three baseline groups while mean triglyceride levels reduced only in the patients that belonged to the medium and high baseline value groups. The baseline values of total cholesterol did not influence the beneficial cholesterol changes in all the patients, while the lack of significant favorable triglyceride changes was influenced by the low baseline values of triglyceride of the patients during doxazosin treatment. A similar study involving lipoprotein fractions and sub-fractions is also in progress. |
| Influence of bezafibrate on hepatic cholesterol metabolism in gallstone patients: reduced activity of cholesterol 7 alpha-hydroxylase Stahlberg, D., E. Reihner, et al. (1995), Hepatology 21(4): 1025-30. Abstract: Bezafibrate is a hypolipidemic fibric acid derivative known to induce cholesterol supersaturation of bile. To characterize its effects on hepatic cholesterol metabolism, 31 normolipidemic, normal-weight patients with gallstones undergoing cholecystectomy were studied. Eleven patients (5 men) were randomized to treatment with bezafibrate, 200 mg three times daily for 4 weeks before operation; the remaining 20 patients (5 men) served as nontreatment controls. At operation, a liver biopsy specimen was obtained under standardized conditions and several important parameters of cholesterol metabolism were assayed. Bezafibrate treatment lowered total plasma cholesterol and triglycerides 30% and 37%, respectively. The hepatic cholesterol 7 alpha-hydroxylase activity was reduced by approximately 60% in the bezafibrate treated patients compared with the controls, whereas the acyl-coenzyme A:cholesterol acyltransferase (ACAT) activity was similar in the two groups. The total 3-hydroxy-3-methylglutaryl coenzyme A (HMG CoA) reductase activity was increased twofold in the treated patients, whereas the active enzyme remained about the same as in the controls. The low-density lipoprotein (LDL) receptor binding activity was unaffected by the treatment. Bezafibrate treatment significantly reduces cholesterol 7 alpha-hydroxylase activity, and it is suggested that this may play an important role for the development of supersaturated bile during such therapy. |
| Influence of bile salt molecular species on cholesterol crystallization from supersaturated model biles Juste, C., I. Catala, et al. (1995), Biochim Biophys Acta 1254(1): 89-97. Abstract: Time-sequential enzymatic determination of cholesterol (CH) crystals harvested by ultrafiltration, and concomitant polarizing light microscopy observations corroborated the striking importance of the bile salts (BS) species in determining CH crystals formation rate from supersaturated model biles incubated in vitro. The more hydrophilic tauroursodeoxycholate, taurohyocholate, glycohyocholate, taurohyodeoxycholate, glycohyodeoxycholate and glyco-3 alpha, hydroxy-6 oxo-5 beta-cholanate inhibited CH precipitation through the formation of a stabilized liquid-crystalline phase. In contrast, in all hydrophobic systems (taurine (T) and glycine (G) conjugates of cholate (C), deoxycholate (DC) and chenodeoxycholate (CDC)), CH crystals precipitated with time. When crystallized CH concentrations were plotted vs. time, the figures showed a sigmoidal pattern, consistent with the transition from metastable systems to stable equilibrium states. Over the equilibration period, the nucleation kinetics (as inferred from enzymatic measurements) and all crystallization events (as microscopically observed) were both shifted in time, depending on the BS species: they were earliest in CDC systems, then in DC systems, and finally in C systems. In the latter, the delay was clearly due to the formation of a transient labile liquid-crystalline phase. G-conjugation also induced a significant delay in CH precipitation, compared to T-conjugation. At last, maximum crystallized CH concentrations at equilibrium were in the decreasing order: C > CDC > DC and T-conjugates > G-homologues. All data are discussed in connection with BS hydrophobicities, with predictions from the phase equilibria of aqueous biliary lipid systems and with new insights into CH crystal habits. |
| Influence of bile salts on molecular interactions between sphingomyelin and cholesterol: relevance to bile formation and stability van Erpecum, K. J. and M. C. Carey (1997), Biochim Biophys Acta 1345(3): 269-82. Abstract: Bile salts enhance secretion of cholesterol into bile and its subsequent solubilization with phosphatidylcholine in mixed micelles. Sphingomyelin, a major structural lipid of the hepatocyte canalicular membrane, and disaturated phosphatidylcholines are known to impede nucleation of solid cholesterol crystals in supersaturated model systems. To understand these effects physico-chemically, we compared the influence of bile salts on interactions of cholesterol with natural sphingomyelins, as well as with dipalmitoyl and egg yolk phosphatidylcholines using various in vitro systems. Submicellar bile salts enhanced significantly bidirectional transfer of dehydroergosterol (a fluorescent cholesterol analog) between sphingomyelin and egg yolk phosphatidylcholine vesicles in the rank order taurocholate < tauroursodeoxycholate < taurodeoxycholate. Quasielastic light scattering of serially diluted sphingomyelin-taurocholate mixtures (1:1 molar ratio, 3 g/dl) revealed metastable temperature-dependent transitions between globular micelles, rod-shaped micelles and vesicles, suggesting that phase transitions under these experimental conditions were metastable only at temperatures below 37 degrees C. Ternary phase diagrams of all sphingomyelins and dipalmitoyl phosphatidylcholine with cholesterol and taurocholate (37 degrees C, 3 g/dl, 0.15 M NaCl) were identical. Compared to systems containing egg yolk phosphatidylcholine, the 1-phase micellar zone and 2- and 3-phase solid cholesterol crystal-containing zones were reduced markedly while the 2-phase zone with stable cholesterol-sphingomyelin liquid crystals was greatly expanded. Our results suggest that the high affinity of cholesterol for sphingomyelin is lost in the presence of bile salts. Our findings may be relevant to secretion of cholesterol into bile and to its inability to crystallize in the hepatocyte canalicular lumen or its surrounding membranes. |
| Influence of breast- and formula-feeding on plasma cholesterol precursor sterols throughout the first year of life Bianchi, C., P. Brambilla, et al. (1997), J Pediatr 131(6): 928-31. Abstract: We evaluated endogenous cholesterol synthesis and plasma lipid profile longitudinally from birth to 1 year old in infants who were exclusively breast-fed (n = 19) or formula-fed (n = 19) for the first 4 months of life. At 1 and 4 months of age, breast-fed infants had higher plasma total and low-density lipoprotein cholesterol and apolipoprotein B levels than formula-fed infants, whereas plasma mevalonate and lanosterol levels were not different between the two study groups. |
| Influence of bromfenvinphos alone, and in mixture with methoxychlor, on levels of gamma-glutamyl transpeptidase, ceruloplasmin and cholesterol in the blood plasma of laboratory mice Zaleska-Freljan, K. I. and J. T. Wolewicz (1993), Pol J Pharmacol 45(3): 309-16. Abstract: Bromfenvinphos 0,0-diethyl-1-(2,4-dichlorophenyl)-2-bromovinyl phosphate, (BrV), 12.33 mg/kg/day alone and in combination with methoxychlor 1,1,1-trichloro-2,2-bis(4-methoxyphenyl)ethane, (MeOCl), 24.66 mg/kg/day were administered daily per os (intragastrically) in pure olive-oil for 6 weeks to male laboratory mice. The activity of gamma-glutamyl transpeptidase (GGTP), ceruloplasmin (CRP), and cholesterol in the blood plasma were determined. The hematocrit value, the erythrocyte count and the weights of the liver, spleen, heart, kidney and gonads were also measured after the end of treatment. BrV and BrV + MeOCl increased the activity of gamma-glutamyl transpeptidase. The activity of ceruloplasmin and the level of cholesterol in the blood plasma as well as the erythrocyte count in the blood were also similar in the control and experimental mice. The hematocrit value decreased after BrV and MeOCl administration. The relative weight of liver was higher in mice receiving both drugs in combination, than in control and in mice receiving BrV alone. The relative weight of spleen was significantly higher in animals receiving BrV alone, than in other groups. |
| Influence of caveolin, cholesterol, and lipoproteins on nitric oxide synthase: implications for vascular disease Everson, W. V. and E. J. Smart (2001), Trends Cardiovasc Med 11(6): 246-50. Abstract: Caveolin-1 traffics cholesterol between the endoplasmic reticulum and cell surface caveolae in a non-vesicle chaperone complex which contains heat shock protein 56, cyclophilin 40, and cyclophilin A. Recent studies demonstrate that endothelial nitric oxide synthase (eNOS), caveolin, hetero-trimeric G-protein coupled receptors, and a calcium channel form an activation complex that is associated with cholesterol-rich caveolae. Oxidized LDL depletes caveolae of cholesterol and prevents agonist stimulation of eNOS by disrupting the activation complex. HDL antagonizes the effects of oxLDL by donating cholesterol to caveolae, thereby preserving the structure and function of caveolae. These findings and others provide a possible mechanistic basis for some of the molecular changes observed in vascular disease. |
| Influence of caveolin-1 on cellular cholesterol efflux mediated by high-density lipoproteins Frank, P. G., F. Galbiati, et al. (2001), Am J Physiol Cell Physiol 280(5): C1204-14. Abstract: Caveolin-1 is a principal structural component of caveolae membranes. These membrane microdomains participate in the regulation of signaling, transcytosis, and cholesterol homeostasis at the plasma membrane. In the present study, we determined the effect of caveolin-1 expression on cellular cholesterol efflux mediated by high-density lipoprotein (HDL). We evaluated this effect in parental NIH/3T3 cells as well as in two transformed NIH/3T3 cell lines in which caveolin-1 protein levels are dramatically downregulated. Compared with parental NIH/3T3 cells, these two transformed cell lines effluxed cholesterol more rapidly to HDL. In addition, NIH/3T3 cells harboring caveolin-1 antisense also effluxed cholesterol more rapidly to HDL. However, this effect was not due to changes in total cellular cholesterol content. We further showed that chronic HDL exposure reduced caveolin-1 protein expression in NIH/3T3 cells. HDL exposure also inhibited caveolin-1 promoter activity, suggesting a direct negative effect of HDL on caveolin-1 gene transcription. Moreover, we showed that HDL-induced downregulation of caveolin-1 prevents the uptake of oxidized low-density lipoprotein in human endothelial cells. These data suggest a novel proatherogenic role for caveolin-1, i.e., regarding the uptake and/or transcytosis of modified lipoproteins. |
| Influence of chitosan feeding of laying hens on egg vitamin and cholesterol content Vrzhesinskaia, O. A., I. V. Filimonova, et al. (2005), Vopr Pitan 74(3): 28-31. Abstract: Chitosan feeding (10 and 20 mg per 1 kg body mass) of 19 week-age laying hens during 1.5 months caused a decrease in whole egg content of vitamin A for 13% and 20% (p < or = 0.05), vitamin E--for 30%, lutein--17% and didn't effect on vitamin B2 level. Chitosan intake lead to cholesterol content 1.5-2 fold decrease and didn't influence on egg yolk lipids concentration. Low dose chitosan-receiving hens had eggs with 1.8-fold increased egg yolk phospholipids level. The most optimal dose of chitosan for the improvement of eggs nutritive value was 10 mg. Under minimal loss in vitamins its administration lead to the pronounced cholesterol decrease and marked phospholipids elevation. |
| Influence of cholesterol and ergosterol on membrane dynamics: a fluorescence approach Arora, A., H. Raghuraman, et al. (2004), Biochem Biophys Res Commun 318(4): 920-6. Abstract: Sterols are essential membrane components of eukaryotic cells and are important for membrane organization and function. Cholesterol is the most representative sterol present in higher eukaryotes. It is often found distributed non-randomly in domains or pools in biological and model membranes. Cholesterol-rich functional microdomains (lipid rafts) are often implicated in cell signaling and membrane traffic. Interestingly, lipid rafts have also recently been isolated from organisms such as yeast and Drosophila, which have ergosterol as their major sterol component. Although detailed biophysical characterization of the effect of cholesterol on membranes is well documented, the effect of ergosterol on the organization and dynamics of membranes is not very clear. We have monitored the effect of cholesterol and ergosterol on the dynamic properties of both fluid (POPC) and gel (DPPC) phase membranes utilizing the environment-sensitive fluorescent membrane probe DPH. Our results from steady state and time-resolved fluorescence measurements show, for the first time, differential effects of ergosterol and cholesterol toward membrane organization. These novel results are relevant in the context of lipid rafts in ergosterol-containing organisms such as Drosophila which maintain a low level of sterol compared to higher eukaryotes. |
| Influence of cholesterol and fasting insulin levels on blood pressure reactivity Bardwell, W. A., M. G. Ziegler, et al. (2000), Psychosom Med 62(4): 569-75. Abstract: OBJECTIVE: This study examined how cholesterol and fasting insulin levels are related to blood pressure reactivity to behavioral stressors. METHODS: Subjects (N = 116) were 20 to 52 years old, at 80% to 150% of ideal weight, and had an average fasting cholesterol level of 183 mg/dl. Stressor tasks included mirror star tracing and a videotaped speech task. Changes from baseline were calculated for systolic and diastolic blood pressure. RESULTS: Neither cholesterol nor insulin was independently related to blood pressure change scores. However, after controlling for body mass, a two-way analysis of variance revealed a significant cholesterol-by-insulin interaction for change in diastolic blood pressure (p =.022). Subjects in the high-cholesterol/high-insulin group showed the greatest increase in diastolic blood pressure reactivity. CONCLUSIONS: In a general population, people with a below-average cholesterol level experience only moderate cardiovascular reactivity to mental stressors regardless of their fasting insulin level. However, for people with an above-average cholesterol level, fasting insulin level is an important factor in determining potential reactivity to mental stressors. These findings highlight the importance of adequate sample size to allow for the analysis of such interactions in future studies of cholesterol, insulin, and blood pressure reactivity. |
| Influence of cholesterol and protein diet on liver cytochrome P-450-dependent monooxygenase system in rats Plewka, A. and M. Kaminski (1996), Exp Toxicol Pathol 48(4): 249-53. Abstract: The influence of the cholesterol and protein diet on the mixed-function oxidases system activity and desaturation of fatty acids were examined. The phenobarbital innducibility of these parameters was analyzed too. Investigations were carried out on Wistar adult male rats. The animals were on the cholesterol (0.25%) and protein diet (32%) during 45 days. The cytochrome P-450 and cytochrome b5 contents, the NADPH-cytochrome P-450 reductase and NADH-cytochrome b5 reductase activities, aniline hydroxylase and 4-aminopyrine N-demethylase activities were measured in the hepatic microsomal fraction. In both sexes, the cholesterol diet decreased all the examined parameters with the exception of NADH-cytochrome b5 reductase activity. The protein diet did not change the examined enzyme activities or levels with the exception of induction of NADH-cytochrome b5 reductase and 4-aminopyrine N-demethylase activities. Simultaneous treatment with phenobarbital had heterogenous effect dependent on the type of diet and examined parameter. |
| Influence of cholesterol crystallization effector proteins on vesicle fusion in supersaturated model bile Hattori, Y., S. Tazuma, et al. (1999), J Gastroenterol Hepatol 14(7): 669-74. Abstract: BACKGROUND: In lithogenic bile, cholesterol-rich vesicles rapidly aggregate and fuse to eventually form cholesterol crystals. This process is modulated by cholesterol crystallization effector substances. In this study, we developed a method for quantitative assessment of vesicle fusion and used it to partly characterize the mechanisms of action of cholesterol crystallization effector proteins. METHODS: Cholesterol:phospholipid (1:1) liposomes were prepared and labelled with octadecyl rhodamine B chloride (R18). Fusion of these liposomes was detected by the increase of R18 fluorescence after incubation with various proteins, such as albumin, concanavalin-A bound glycoprotein, immunoglobulins, apolipoprotein A-I and apolipoprotein B (all at 100 microg/mL). RESULTS: Fusion of cholesterol/phospholipid liposomes was increased by 16 and 14% in the presence of concanavalin-A bound glycoprotein and immunoglobulins, respectively, and decreased by 21 and 9% after addition of apolipoprotein A-I and apolipoprotein B, respectively. The effect of each protein on vesicle fusion was correlated with its hydrophobicity. CONCLUSIONS: These results suggest that nucleation effector proteins modulate the stability of vesicles and, thus, affect cholesterol crystallization. Such modulation is based upon protein-vesicle association, which defines the physico-chemical metastability of vesicular cholesterol. |
| Influence of cholesterol derivatives on cytoskeletal organization of human carcinoma cells Ludes, B., A. C. Schmit, et al. (1993), Eur Urol 23(4): 490-501. Abstract: Recent developments of immunotherapeutic approaches have shown that artificial ordering of tumor cell membranes with cholesterol hemisuccinate (CHS) or 25-hydroxycholesterol (25-OH) may significantly enhance the immunogenicity of human renal adenocarcinoma cells. To gain further insight into the molecular mechanism of these sterols, we investigated cytoskeletal modification, which is related to the cell membrane. After treatment of human renal carcinoma cells with these cholesterol (at 10(-6) and 10(-7) M) for 5 days, we observed a disorganization of the submembrane end of the cytoplasmic actin stress fibers by cytofluorescence. The microtubule network was not affected. Thus, in the present study, we found that changes in membrane physicochemical properties impaired the anchorage of actin microfilaments in the plasma membrane of human renal cancer cells. Under the same experimental conditions, such modifications were not observed in normal cells (human fibroblasts) or in human hepatoma cells. We suggest that incubation of cancer cells with these sterols induced a redistribution of the cholesterol-rich membrane microdomains which are linked to the cytoskeleton through submembrane proteins. |