| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Cholesterol in remnant-like lipoproteins in human serum using monoclonal anti apo B-100 and anti apo A-I immunoaffinity mixed gels Nakajima, K., T. Saito, et al. (1993), Clin Chim Acta 223(1-2): 53-71. Abstract: We have developed a simple, rapid assay method for apo E-rich lipoproteins (d < 1.006 g/ml), using an immunoaffinity gel mixture of anti apo B-100 and apo A-I antibodies coupled to Sepharose 4B. The immunoaffinity mixed gels adsorb normal lipoproteins containing apo A-I quantitatively as well as most lipoproteins containing apo B-100. Unbound lipoproteins are quantified by assay of cholesterol. Characterization of the unbound lipoproteins of d < 1.006 g/ml (J Lipid Res 1992; 33: 369-380) has shown that they represent chylomicron and VLDL remnant-like particles (RLP). RLP-Cholesterol(C) levels in plasma have been determined in 363 male and female normolipidemic subjects (mean +/- S.D.: 72 +/- 16 mg/l) and have been found to be higher in patients with coronary heart disease and familial dysbetalipoproteinemia. Triglyceride-rich lipoproteins may well contain both atherogenic and non-atherogenic particles that can be separated by this simple immunoadsorption assay. |
| Cholesterol in serum and vaginal content in healthy, non-pregnant women Laube, T. and H. Spitzbart (1990), Zentralbl Gynakol 112(18): 1171-4. Abstract: We examined 97 healthy and non-pregnant women aged between 17 and 58 years, who especially did not show any symptoms of vulvitis or colpitis, for the contents of cholesterol in serum and vaginal smear. In the vaginal smear we found significantly lower concentrations of total cholesterol as in serum, whereas the part of free cholesterol on total cholesterol in vaginal smear was triple than in serum and its absolutely concentration was double than that in serum. Possible reasons are discussed. |
| Cholesterol in serum, liver and small intestine under different dietary compositions Pugalendhi, K. V. and S. Ramakrishnan (1990), Indian J Exp Biol 28(9): 895-7. Abstract: Decrease in serum total cholesterol was noted in albino rats fed with low protein diet. Decrease was also noted in the tissues like liver, duodenum, jejunum and ileum in high protein diet, and jejunum and ileum in low protein diet. There was an increase of serum free cholesterol in low protein diet. All the tissues studied had less free cholesterol in high protein diet. Jejunum showed a decrease in low protein diet also. Serum total cholesterol increased in high fat diet. Free cholesterol increased in both the cases. Tissue total cholesterol was raised in low and high fat diets in liver, duodenum, jejunum and ileum. Free cholesterol was raised in duodenum and ileum in both high and low fat diets while that of liver and jejunum was increased only in low fat group. |
| Cholesterol in signal transduction Incardona, J. P. and S. Eaton (2000), Curr Opin Cell Biol 12(2): 193-203. Abstract: Membrane cholesterol impinges on signal transduction in several ways, which is highlighted in particular by the Hedgehog signaling pathway. In Hedgehog signaling, cholesterol is important for ligand biogenesis, as well as for signal transduction in receiving cells. Hedgehog ligands are post-translationally modified by cholesterol, and the Hedgehog receptor, Patched, is structurally similar to the Niemann-Pick C1 protein, which functions in intracellular lipid transport. Although the exact role of cholesterol in Hedgehog signal transduction remains elusive and is probably multifaceted, studies over the past year have implicated raft membrane subdomains, cholesterol transport and a link between protein and lipid trafficking in endocytic compartments. |
| Cholesterol in Spanish children and adolescents. Uncertain outlook for the future cardiovascular risk of the population Ros Rahola, E. (1991), Med Clin (Barc) 97(10): 377-9. |
| Cholesterol in the distal portions of differentiating and fully differentiated rat odontoblasts observed by freeze-fracture Franklin, D. L., V. E. Arana-Chavez, et al. (1994), Arch Oral Biol 39(9): 817-9. Abstract: Freeze-fracture replicas of rat molar tooth germs in conjunction with the 3-beta-hydroxysterol marker filipin were used to study the distribution of cholesterol in the distal portions of odontoblast plasma membrane. Filipin-sterol deformations (interactions) appeared as clusters interspersed with deformation-free regions on the distal plasma membrane of early differentiating odontoblasts. In fully differentiated odontoblasts, the whole distal membrane, including the process, was occupied by packed deformations with no free regions. It seems that early developing odontoblasts are poorer in cholesterol than the fully differentiated cells. As the content and/or distribution of 3-beta-hydroxysterols (cholesterol) is known to influence membrane fluidity, the low cholesterol content of early differentiating odontoblasts might be related to the fluidity required for the budding off of matrix vesicles. |
| Cholesterol in the elderly. Is it important? Hulley, S. B. and T. B. Newman (1994), Jama 272(17): 1372-4. |
| Cholesterol in the pleural fluid Moya Mir, M. S., L. Lopez Jimenez, et al. (1993), Rev Clin Esp 192(2): 92. |
| Cholesterol in the separation of transudates and exudates Vaz, M. A., E. Marchi, et al. (2001), Curr Opin Pulm Med 7(4): 183-6. Abstract: The Light criteria represent the most acceptable method to separate transudates and exudates. However, approximately 10% of patients with transudates, especially those with congestive heart disease, are misdiagnosed with these criteria. To improve diagnostic accuracy, many biochemical markers have been proposed as alternatives to differentiate transudates and exudates. Cholesterol has raised particular interest because only pleural fluid is needed, which makes blood samples unnecessary and simplifies the procedure. In most clinical studies, cholesterol has been shown to be as sensitive as the Light criteria, although it is less specific. Other randomized studies are necessary to determine the real potential value of pleural-fluid cholesterol measurements. Studies of pleural-fluid cholesterol are aimed at better understanding the mechanisms by which cholesterol enters the pleural cavity and its role in diseases. The ideal cutoff point of cholesterol to differentiate transudates and exudates is still unknown. Recently, aspects of the cholesterol turnover in diseases have raised great interest. Cholesterol generated great interest after it was related to coronary artery diseases. The involvement of cholesterol in the atherosclerotic process is well known, although its importance in body cavities is still unclear. |
| Cholesterol in the year 2000 Vance, D. E. and H. Van den Bosch (2000), Biochim Biophys Acta 1529(1-3): 1-8. Abstract: Cholesterol research was one of the key areas of scientific investigation in the 20th century. Little was known about the structure of cholesterol until the pioneering research of A. Windaus and H. Wieland in the first part of the century. The structure of cholesterol was completely elucidated in 1932. With the development of isotopic tracers in the 1930s studies on cholesterol biosynthesis were initiated. In 1942 K. Bloch and D. Rittenberg showed that deuterium-labeled acetate was incorporated into the ring structure and side chain of cholesterol. Another important discovery from Bloch's laboratory was that squalene was a precursor of cholesterol. In 1956, the main elements of the biosynthetic pathway became known when isopentenyl pyrophosphate was discovered as a precursor. In 1966, J. Cornforth and G. Popjak predicted that there were 16234 possible stereochemical pathways by which mevalonate could be converted into squalene. They subsequently showed which of these pathways was correct. In the 1970s and 1980s K. Bloch was able to provide intriguing evidence for an evolutionary advantage of cholesterol over lanosterol or some of the intermediates in the conversion of lanosterol to cholesterol. The last quarter of the 20th century was when M. Brown and J. Goldstein showed that the low density lipoprotein receptor was a key regulator of cholesterol homeostasis. They have also demonstrated that cholesterol balance in the cell is transcriptionally regulated via the sterol regulatory element binding protein. In the later part of the 20th century drugs were developed that effectively lower plasma cholesterol and lessen the risk of atherosclerosis and cardiovascular disease. |
| Cholesterol in vascular and valvular calcification Demer, L. L. (2001), Circulation 104(16): 1881-3. |
| Cholesterol inclusion in liposomes affects induction of antigen-specific IgG and IgE antibody production in mice by a surface-linked liposomal antigen Nakano, Y., M. Mori, et al. (2002), Bioconjug Chem 13(4): 744-9. Abstract: In the previous study, we investigated the induction of ovalbumin (OVA)-specific antibody production in mice by OVA-liposome conjugates made using four different lipid components, including unsaturated carrier lipid and three different saturated carrier lipids. All of the OVA-liposome conjugates tested induced IgE-selective unresponsiveness. The highest titer of anti-OVA IgG was observed in mice immunized with OVA-liposomes made using liposomes with the highest membrane fluidity, suggesting that the membrane fluidity of liposomes affects their adjuvant effect. In this study, liposomes with five different cholesterol inclusions, ranging from 0% to 43% of the total lipid, were made, and the induction of OVA-specific antibody production by OVA-liposome conjugates was compared among these liposome preparations. In contrast to the results in the previous study, liposomes that contained no cholesterol and possessed the lowest membrane fluidity demonstrated the highest adjuvant effect for the induction of IgG antibody production. In addition, when the liposomes with four different lipid compositions were used, OVA-liposome conjugates made using liposomes that did not contain cholesterol induced significantly higher levels of anti-OVA IgG antibody production than did those made using liposomes that contained cholesterol and, further, induced significant production of anti-OVA IgE. These results suggest that cholesterol inclusion in liposomes affects both adjuvanticity for IgG production and regulatory effects on IgE synthesis by the surface-coupled antigen of liposomes. |
| Cholesterol increase in mitochondria: its effect on inner-membrane functions, submitochondrial localization and ultrastructural morphology Echegoyen, S., E. B. Oliva, et al. (1993), Biochem J 289 (Pt 3): 703-8. Abstract: The effect of cholesterol incorporation on some functions of the mitochondrial inner membrane and on the morphology of rat liver mitochondria was studied. Basal ATPase and succinate dehydrogenase activities remained unchanged after cholesterol was incorporated into the mitochondria; however, uncoupled ATPase activity was partially inhibited. The presence of several substrates and inhibitors did not change the amount of cholesterol incorporated, which was localized mostly in the outer membrane. Electron-microscope observations revealed the presence of vesicles between the outer and inner membranes; these vesicles increased in number with the amount of cholesterol incorporated. The data suggest that cholesterol induces the formation of vesicles from the outer membrane, and modifies the activity of stimulated ATPase. |
| Cholesterol increases the L-type voltage-sensitive calcium channel current in arterial smooth muscle cells Sen, L., R. A. Bialecki, et al. (1992), Circ Res 71(4): 1008-14. Abstract: To determine whether membrane free cholesterol affects calcium currents in vascular smooth muscle cells, whole-cell patch clamp recordings were made before and after cholesterol enrichment of cells by exposure to cholesterol-rich liposomes. Exposure to cholesterol-rich liposomes resulted in a gradual increase in the L-type current over 20 hours and a plateau (73 +/- 7% increase over basal) between 20 and 32 hours. This effect was associated with a rightward shift in the inactivation potential and a decrease in the sensitivity to (-)-PN-202-791, a dihydropyridine antagonist. There was no change in the maximum L-type current stimulated by (+)-PN-202-791, a dihydropyridine agonist. Liposome exposure caused a small, transient increase in the T-type current (peak effect, 20 minutes). We conclude that membrane cholesterol has important effects on the L-type calcium current in vascular smooth muscle cells, which is most likely due to an alteration in channel functional state rather than an increase in channel expression. |
| Cholesterol increases the thermal stability of the Ca2+/Mg(2+)-ATPase of cardiac microsomes Ortega, A., J. Santiago-Garcia, et al. (1996), Biochim Biophys Acta 1283(1): 45-50. Abstract: The effect of membrane cholesterol on the thermal inactivation of Ca2+/Mg(2+)-ATPase activity of bovine cardiac microsome was measured and compared to the thermal denaturation profiles of the microsomes as measured by differential scanning calorimetry (DSC). Inactivation, defined as loss of activity, and denaturation, defined as conformational unfolding, were irreversible under the conditions used. Both thermal inactivation of Ca2+/Mg(2+)-ATPase activity and thermal denaturation were shifted to higher temperatures in microsomes enriched with cholesterol (37 +/- 5 micrograms cholesterol/mg protein, cholesterol/phospholipid molar ratio 0.31) compared to control microsomes (15 +/- 3 micrograms cholesterol/mg protein, molar ratio 0.12). Thermal inactivation was measured by two methods: first, measuring activity at room temperature as a function of heating to elevated temperatures at 1 K/min, where inactivation temperatures (T1, temperature of half activity) were 58.9 +/- 0.3 degrees C for control membranes and 59.9 +/- 0.1 degrees C for cholesterol-enriched membranes, respectively. Second, measuring ATPase activity as a function of time at constant temperature, where T1 values of 57.6 +/- 0.5 degrees C and 59.2 +/- 0.5 degrees C were determined for control and cholesterol-enriched membranes, respectively. DSC profiles of microsomal membranes consisting of a number of overlapping peaks were obtained. A well resolved component (transition C) was observed with a transition temperature (T 1/2) of 58.2 degrees C. This T 1/2, which is a measure of conformational stability, correlates with the T1 for Ca2+/Mg(2+)-ATPase activity and is 1.9 +/- 0.6 K higher in cholesterol-enriched membranes. Thus, the increased resistance to inactivation appears to be due to increased conformational stability of the protein induced by cholesterol, demonstrating that a change in lipid composition can influence the stability of an integral membrane protein in a natural membrane. The increased stability is of sufficient magnitude to account for the previously observed correlation between cholesterol content and resistance to heat shock in several cell lines. |
| Cholesterol index of hair in normal and hypercholesterolemic mice Kobayashi, K. and H. Igimi (1995), Clin Chem 41(12 Pt 1): 1775. |
| Cholesterol induce oligomerization of Vibrio vulnificus cytolysin specifically Kim, B. S. and J. S. Kim (2002), Exp Mol Med 34(3): 239-42. Abstract: Vibrio vulnificus cytolysin (VVC) has been implicated as one of the important virulence determinants of V. vulnificus that causes serious septicemia and wound infection. An attempt was made to investigate that VVC could act as a ligand which stimulates intracellular signaling systems. Cholesterol dose-dependently blocked VVC hemolytic activity through oli-gomerization of cytolysin. Among cholesterol derivatives including 7-dehydrocholesterol, cholesteryl esters, deoxycholate, and cholestane tested, only 7-dehydrocholesterol induced oligomerization as well as inactivation of VVC. These results show that oligomerization of VVC is completely dependent on three-dimensional structure of cholesterol where specific interaction of cholesterol at oligomerization sites of VVC is very selective. These findings support the idea that cholesterol which constitute many of cellular plasma membrane could be a receptor of VVC on plasma membrane of target cells. |
| Cholesterol induced lipid accumulation in cardiomyocytes Aviram, M. (1993), Cardiovasc Res 27(3): 538. |
| Cholesterol induced lipid accumulation in myocardial cells of rats Hexeberg, S., N. Willumsen, et al. (1993), Cardiovasc Res 27(3): 442-6. Abstract: OBJECTIVE: The aim was to investigate whether cholesterol feeding of rats for only 10 d would result in lipid accumulation in myocardial cells and a change in the peroxisomal beta oxidation in the heart compared to the hearts of rats on standard feeds. METHODS: Eight rats received a cholesterol diet (2%) and eight rats received a standard diet for 10 d. Lipids were measured in serum, liver, and heart. Palmitoyl-CoA hydrolase and fatty acyl-CoA oxidase were determined in total homogenate of hearts. The fractional volume of lipid droplets in myocardial cells was calculated from micrographs at a magnification of x9600 obtained by electron microscopy. RESULTS: The fractional volume of lipid droplets in the cardiomyocytes increased from 0.109(SEM 0.019)% to 0.259(0.037)%, (p < 0.003), as a result of cholesterol feeding. Cholesterol and triglycerides in the heart measured by biochemical methods increased by 13% and 24%, respectively. There was no difference in palmitoyl-CoA hydrolase or fatty acyl-CoA oxidase in the hearts of the cholesterol fed group compared to the control group, suggesting an unaltered peroxisomal beta oxidation of fatty acids in the myocardium. The serum triglycerides and serum phospholipids were reduced in the cholesterol fed rats (p < 0.05 and p < 0.001, respectively). Rats fed cholesterol diet showed a reduced ratio of HDL cholesterol to total cholesterol in serum, together with an increased liver weight and relative liver weight compared to the control rats. The addition of cholesterol to the diet increased liver cholesterol to 21.0(1.6) mumol.g-1 wet weight compared to 5.87(0.93) mumol.g-1 in the controls on standard diet (p < 0.0001). Cholesterol feeding had no effect on the hepatic level of phospholipids, but the liver triglycerides tended to increase from 23.3(9.5) mumol.g-1 wet weight to 53.3(6.3) mumol.g-1. CONCLUSIONS: Lipid accumulation in the myocardial cells was shown by morphometry after 10 d of cholesterol feeding, without any visible damage to the tissue. |
| Cholesterol induced variations of membrane dynamics related to the induction of apoptosis in mouse thymocytes Hartel, S., F. Ojeda, et al. (1998), Int J Radiat Biol 74(5): 607-15. Abstract: PURPOSE: To evaluate the involvement of cholesterol induced variations of membrane dynamics in mouse thymocyte apoptosis. MATERIALS AND METHODS: Membranes of thymocytes of RK mice were enriched with cholesterol using methyl-beta-cyclodextrins as carriers. Spontaneous apoptosis was compared with apoptosis induced either by X-irradiation, by treatment with dexamethasone (DEX), and by phorbol-12-myristate-13-acetate (PMA). Apoptotic cells were quantified by means of flow cytofluorometry. RESULTS: Small amounts of incorporated cholesterol enhance the cellular sensitivity for spontaneous apoptosis whereas larger amounts of incorporated cholesterol protect against spontaneous apoptosis and apoptosis induced by irradiation, DEX, or PMA. CONCLUSIONS: Cholesterol exerts specific rigidity effects on lipid membranes which have been shown to be involved in thymocyte apoptosis. The general effect of higher concentrations of cholesterol protecting against apoptosis hints towards a central protective mechanism. This study believes that either cholesterol paralyses great parts of the cell metabolism or that the apoptotic chain reaction is interrupted at a central point due to protection of membrane lipid regions from oxidative stress. |