| For medical practitioners and the general public - Cholesterol Journal Article Catalog. |
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| Relationships of alpha-linolenic acid to platelet fatty acid composition and trans content of cholesterol-free foods Holub, B. J. and B. Celi (1992), Nutrition 8(2): 136-8. |
| Relationships of body mass index with blood pressure and serum cholesterol concentrations at different ages Wakabayashi, I. (2004), Aging Clin Exp Res 16(6): 461-6. Abstract: BACKGROUND AND AIMS: Only limited information has been available on the effects of age on the relationship between obesity and other atherosclerotic risk factors, such as blood pressure and serum lipids. The purpose of this study was to investigate the effects of age on the relationships of obesity with blood pressure and serum cholesterol concentrations. METHODS: A community-based cross-sectional study was performed on 157,902 workers in Yamagata, Japan. Blood pressure and serum total and HDL cholesterol concentrations were measured, and body mass index (BMI) and atherogenic index were calculated. The correlations of BMI with blood pressure, serum cholesterol concentrations and atherogenic index in different age groups were compared. RESULTS: BMI showed significant positive correlations with systolic and diastolic blood pressures, serum total cholesterol level and atherogenic index, and showed a significant negative correlation with serum HDL cholesterol level. The relationships of BMI with systolic and diastolic blood pressures became weaker with advancing age in both men and women after 30 and 40 years of age, respectively. The relationships of BMI with serum total cholesterol level and atherogenic index also became weaker with advancing age after 30 years of age in men and after 40 years of age in women. There was no age-dependent tendency in the relationship between BMI and HDL cholesterol, however. The above age-dependent changes were more prominent in men than in women. CONCLUSION: The relationships of obesity with blood pressure, serum total cholesterol level and atherogenic index in the elderly are much weaker than in the young. |
| Relationships of dietary fat consumption to serum total and low-density lipoprotein cholesterol in hispanic preschool children Shea, S., C. E. Basch, et al. (1991), Prev Med 20(2): 237-49. Abstract: BACKGROUND. Studies of the relationship between dietary fat intake and serum lipids in young children have yielded inconclusive results. We studied this relationship in 108 Hispanic children ages 4-5 years. METHODS. Four 24-hr recalls approximately 3 months apart and two Willett semiquantitative food frequency questionnaires approximately 6 months apart were obtained by interviewing the children's mothers. Diet measures were averaged for the multiple administrations of each of these instruments. RESULTS. Based on the 24-hr recalls, children in the highest tertile of total fat consumption (36.2% of total calories) compared with the lowest tertile (30.2% of total calories) had mean total serum cholesterol of 4.32 mmol/liter (167 mg/dl) vs 3.91 mmol/liter (151 mg/d) (test for linear trend across tertiles, P less than 0.05) and mean low-density lipoprotein cholesterol of 2.74 mmol/liter (106 mg/dl) vs 2.29 mmol/liter (89 mg/dl) (test for linear trend, P less than 0.01). Children in the highest tertile of saturated fat consumption (14.6% of total calories) compared with the lowest tertile (11.2% of total calories) had mean total serum cholesterol of 4.39 mmol/liter (170 mg/dl) vs 3.97 mmol/liter (154 mg/dl) (test for linear trend, P less than 0.05) and mean low-density lipoprotein cholesterol of 2.80 mmol/liter (108 mg/dl) vs 2.35 mmol/liter (91 mg/dl) (test for linear trend, P less than 0.01). These relationships remained significant when calorie-adjusted nutrient intakes were examined and after adjustment in multiple linear regression models for age, sex, and body mass index, with the exception of the association of calorie-adjusted total fat with total serum cholesterol level (P = 0.07). Similar results were obtained using the Willett questionnaires. CONCLUSIONS. These findings indicate that dietary fat, particularly saturated fat consumption, is an important correlate of blood lipid levels in preschool children. These are also the first reported data indicating that the Willett questionnaire, as a method for measuring the atherogenic components of diet, has criterion-related validity in young children. |
| Relationships of light and heavy fetuses to uterine position, placental weight, gestational age, and fetal cholesterol concentrations Wise, T., A. J. Roberts, et al. (1997), J Anim Sci 75(8): 2197-207. Abstract: With emphasis on increasing litter size to improve productivity and profitability, lightweight pigs born will increase in number as litter size increases and may be problematic due to reduced neonatal survival of lightweight pigs. To study developmental aspects of lightweight fetuses, fetal and placental weights were evaluated at three stages of pregnancy (30, 70, and 104 d) from white composite gilts (n = 88, 123, and 135, respectively) in relation to uterine position of light and heavy fetuses. Fetal cholesterol concentrations were analyzed at the beginning (d 70) and end (d 104) of the in utero growth phase (last third of gestation). At 30 d of gestation, no differences were noted between fetal weight and position within the uterine horn, but at 70 d and 104 d of pregnancy, heavy fetuses were found at the tubal ends and light fetuses at the cervical ends of the uterus. Using the criteria of +/- 1 SD or +/- 2 SD of the mean and lower and upper 10 or 20% of fetal weights for each gestational age, light and heavy fetuses in conjunction with their placentas were different from population means at all stages of gestation. Cholesterol concentrations were lower in light fetuses (d 104) and increased in heavy fetuses. In 28 litters (d 104) selected for extremes in within-litter fetal weights, concentrations of IGF-I increased with fetal weight (P <.01), which suggests that growth and development of lightweight pigs may be limited by critical endocrine components. |
| Relationships of liver weight, cholesterol, albumin and alpha2-macroglobulin concentrations with ovarian function in swine Wise, T. and J. J. Ford (1998), J Steroid Biochem Mol Biol 67(5-6): 383-90. Abstract: In two genetic swine models selected for diversity in ovulation rates (White composite controls and ovulation rate selection line, n = 131; 1/2 White composite: 1/2 Meishan crossbreds, n = 387), a positive relationship was established with liver weight and ovulation rate (P < 0.01). Serum changes of cholesterol, albumin and alpha2-macroglobulin were monitored during various stages of the luteal phase and follicular phase (days 17 and 19 of the estrous cycle; 1/2 White composite: 1/2 Meishan gilts). Serum cholesterol concentrations increased with liver weights (r = 0.19; P < 0.01) and corpora lutea numbers (r = 0.14; P < 0.01). Albumin concentrations were negatively correlated with corpora luteal numbers (r = -0.3; P < 0.01) but had no relationship with liver weight. Serum concentrations of alpha2-macroglobulin were not related to liver weight or corpora lutea numbers. Circulating concentrations of cholesterol and alpha2-macroglobulin increased with day of the estrous cycle (P < 0.01). Testosterone concentrations were inversely related to circulating cholesterol concentrations during the estrous cycle, but testosterone concentrations on day 17 or 19 of the cycle were unrelated to corpora lutea numbers. Concentrations of estrone on day 17 or 19 (as an index of follicles destined to ovulate) were also not related to numbers of corpora lutea. Many interactions between liver and ovarian function involving metabolic and endocrine systems are plausible, but defined mechanisms resulting in coordinate increases in liver weight and ovulation rates are presently unelucidated. |
| Relationships of serum plant sterols (phytosterols) and cholesterol in 595 hypercholesterolemic subjects, and familial aggregation of phytosterols, cholesterol, and premature coronary heart disease in hyperphytosterolemic probands and their first-degree relatives Glueck, C. J., J. Speirs, et al. (1991), Metabolism 40(8): 842-8. Abstract: To assess relationships of serum phytosterols (plant sterols P) to serum cholesterol (C), P were measured by gas-liquid chromatography (GLC) in 595 hypercholesterolemics (top C quintile in screening of 3,472 self-referred subjects). A second specific aim was to determine whether high serum P would track over time and whether they would predict familial aggregation of high C, high low-density lipoprotein cholesterol (LDLC), high apolipoprotein (apo) B, and increased premature coronary heart disease (CHD) in hyperphytosterolemic probands and their first-degree relatives. Mean +/- (SD) C was 260 +/- 56 mg/dL, campesterol (CAMP) was 2.10 +/- 1.6 micrograms/mL, stigmasterol (STIG) 1.71 +/- 1.67, sitosterol (SIT) 2.98 +/- 1.61, and total P 6.79 +/- 3.66 micrograms/mL. Serum C correlated with CAMP (r =.15, P less than or equal to.001), STIG (r =.10, P less than or equal to.02), SIT (r =.34, P less than or equal to.0001), and total P (r =.29, P less than or equal to.0001). High serum CAMP and STIG were associated with a personal or family history of CHD in subjects less than or equal to age 55 years (premature CHD). In 21 hyperphytosterolemic probands who initially had at least one P at or above the 95th percentile and a second P at or above the 75th percentile, P were remeasured 2 years later. Initial and 2-year follow-up CAMP, STIG, and SIT did not differ (P greater than.7). Initial and follow-up CAMP were correlated (r =.47, P =.03).(ABSTRACT TRUNCATED AT 250 WORDS) |
| Relative and biomarker-based validity of a food-frequency questionnaire estimating intake of fats and cholesterol Feunekes, G. I., W. A. Van Staveren, et al. (1993), Am J Clin Nutr 58(4): 489-96. Abstract: The relative validity of a 104-item food-frequency method to assess intakes of fats and cholesterol was tested against the dietary history of 191 men and women. Pearson correlation coefficients ranged from 0.38 for linoleic acid (% of energy) to 0.83 for energy intake, with 0.78 and 0.75 for the intakes of total fat and saturated fatty acids, respectively. Mean intakes were overestimated by the food-frequency questionnaire relative to the dietary history by 5% for energy and monounsaturated fatty acids (% of energy) and up to 30% for linoleic acid intake. Linoleic acid concentrations in erythrocytes and adipose tissue were used as biomarkers of intake. The correlation of the linoleic acid intake according to the food-frequency questionnaire with linoleic acid in erythrocytes and adipose tissue was 0.44 and 0.28, respectively, and the dietary history gave similar values. The food-frequency questionnaire gives results similar to those from the dietary history and is thus considered appropriate for classifying subjects according to their fat intake. |
| Relative effects of feeding saturated fats and cholesterol on fluidity of rabbit lipoproteins Berlin, E., S. G. Shapiro, et al. (1991), Comp Biochem Physiol A 98(2): 343-6. Abstract: 1.The effects of saturated fat and cholesterol on lipoprotein fluidity were tested in New Zealand white rabbits fed diets containing corn oil (CO) or cocoa butter (CB) with and without added 0.2% cholesterol. 2. Saturated fats had little effect on fluidity in any lipoprotein fraction. 3. Cholesterol feeding dramatically reduced fluidity in VLDL and LDL, but minimal change was noted in HDL. 4. Cholesterol-fed rabbits were hypercholesteroloemic throughout the 10-month study. 5. The rabbits became adapted to cholesterol feeding as VLDL became more fluid with time. |
| Relative efficacy of atorvastatin 80 mg and pravastatin 40 mg in achieving the dual goals of low-density lipoprotein cholesterol <70 mg/dl and C-reactive protein <2 mg/l: an analysis of the PROVE-IT TIMI-22 trial Ridker, P. M., D. A. Morrow, et al. (2005), J Am Coll Cardiol 45(10): 1644-8. Abstract: OBJECTIVES: The aim of this research was to compare relative efficacy of different statin regimens in achieving the dual goals of low-density lipoprotein cholesterol (LDL-C) and C-reactive protein (CRP) reduction. BACKGROUND: While secondary prevention guidelines for statin therapy suggest lowering LDL-C levels <70 mg/dl, we have recently shown that clinical outcomes are improved when CRP levels are also lowered <2 mg/l. METHODS: We addressed the relative efficacy of pravastatin 40 mg and atorvastatin 80 mg daily to reduce LDL-C and CRP among 3,745 acute coronary syndrome patients. RESULTS: A total of 1,018 participants (27.1%) achieved the dual goals of LDL-C <70 mg/dl and CRP <2 mg/l. After adjustment for age, gender, smoking, diabetes, hypertension, obesity, and HDL-C, these individuals had a 28% lower risk of recurrent myocardial infarction or vascular death (relative risk = 0.72; 95% confidence interval 0.52 to 0.99). Of those who achieved dual goals, 80.6% received atorvastatin 80 mg, while 19.4% received pravastatin 40 mg (p < 0.001). Only 11% allocated pravastatin and 44% allocated atorvastatin achieved the goals of LDL-C <70 mg/dl and CRP <2 mg/l, and only 5.8% allocated pravastatin 40 mg and 26.1% allocated atorvastatin 80 mg reached the even lower goals of LDL-C <70 mg/dl and CRP <1 mg/l. The correlation coefficient for CRP measured at 30 days and at end of study was 0.61 (p < 0.001), a value almost identical to that for LDL-C over the same follow-up period (r = 0.62, p < 0.001). CONCLUSIONS: While atorvastatin 80 mg was superior to pravastatin 40 mg in terms of achieving the dual goals of aggressive LDL-C and CRP reduction, neither agent brought the majority of patients below thresholds needed to maximize patient benefit. |
| Relative impact of low-density lipoprotein-cholesterol concentration and insulin resistance on carotid wall thickening in nondiabetic, normotensive volunteers Wang, P. W., C. W. Liou, et al. (2002), Metabolism 51(2): 255-9. Abstract: The relative effect of an increase in low-density lipoprotein-cholesterol (LDL-C) concentration, as compared with insulin resistance and its manifestations, on intimal medial thickening (IMT) of the common carotid artery was defined in 72 healthy men and women. Insulin-mediated glucose disposal was quantified by the insulin suppression tests, in which the height of the steady-state plasma glucose (SSPG) concentration during the last 30 minutes of a 180-minute infusion of octreotide, insulin, and glucose provides an estimate of insulin resistance. IMT was determined by high-resolution B-mode ultrasonography. Univariate analyses defined statistically significant correlation coefficients between IMT and LDL-C concentration (r =.25, P <.05), SSPG concentration (r =.32, P <.01), triglycerides (TG) (r =.25, P <.05), and high-density lipoprotein-cholesterol (HDL-C) (r = -.28, P <.05) concentrations (changes associated with insulin resistance) and ratio of waist-to-hip girth (r =.29, P <.05). When forward step-wise linear regression analysis was used, concentrations of SSPG, LDL-C and HDL-C all emerged as independent predictors of IMT (P <.05). Furthermore, the magnitude of their relationship to IMT values was comparable. These results provide evidence that insulin resistance is as significant a predictor of degree of atherogenesis (estimated by IMT) of the common carotid artery as a high LDL-C concentration. |
| Relative potencies of statins in reducing cholesterol synthesis and enhancing linoleic acid metabolism Rise, P., S. Ghezzi, et al. (2003), Eur J Pharmacol 467(1-3): 73-5. Abstract: Simvastatin enhances the conversion of linoleic acid to their long chain polyunsaturated fatty acid derivatives, e.g. arachidonic acid, in addition to typically inhibiting the de novo cholesterol synthesis, in cultured cells. The dose-response relationships for the above effects show that simvastatin, atorvastatin and fluvastatin affect linoleic acid conversion and the delta5 desaturase step more potently than the synthesis of cholesterol, simvastatin being the most effective in inhibiting sterol synthesis, whereas atorvastatin in stimulating the conversion of linoleic acid. |
| Relative risk of factors for coronary heart disease in population with low cholesterol levels Onat, A. and M. S. Senocak (1994), Int J Cardiol 43(1): 51-60. Abstract: We studied the odds ratios of seven leading risk variables in a population essentially having a 'low' cholesterol concentration. In a cross-sectional population-based study of 3689 Turkish adults 20 years of age or over, 90 men and 83 women were diagnosed to have definite or suspected coronary heart disease. The criteria were based on history, cardiovascular examination and on Minnesota coding of electrocardiograms. Potential risk factors studied were: plasma total cholesterol (> or = 240 mg/dl), fasting triglycerides (> or = 200 mg/dl), diabetes mellitus, hypertension (asystolic > or = 160 mmHg, diastolic > or = 95 mmHg, or both, or subjects reporting to take antihypertensive medication), smoking currently or in the past, obesity (body mass index > or = 30 kg/m2), and physical inactivity. Hypertension and lack of physical exercise constituted the most important risk factors in both sexes being valid for all age groups and having high attributable risks; odds ratios in men and women, respectively, were 3.16 and 2.6 for hypertension, and 2.16 and 3.49 for physical inactivity. Hypertriglyceridemia followed these factors in men with an odds ratio of 2.15. In women an additional significant factor was obesity (odds ratio 1.76), while diabetes and hypercholesterolemia revealed to be significant only in those aged 20-59 years, and smoking in women aged 30-59 years. Among men, smoking was a borderline significant risk factor for coronary disease, whereas hypercholesterolemia did not prove to be so. These findings, somewhat at variance with those of industrialized nations, may have significance for policy of cardiovascular disease prevention in third-world populations. |
| Release of cellular cholesterol: molecular mechanism for cholesterol homeostasis in cells and in the body Yokoyama, S. (2000), Biochim Biophys Acta 1529(1-3): 231-44. Abstract: Most mammalian somatic cells are unable to catabolize cholesterol and therefore need to export it in order to maintain sterol homeostasis. This mechanism may also function to reduce excessively accumulated cholesterol, which would thereby contribute to prevention or cure of the initial stage of atherosclerotic vascular lesion. High-density lipoprotein (HDL) has been believed to play a main role in this reaction based on epidemiological evidence and in vitro experimental data. At least two independent mechanisms are identified for this reaction. One is non-specific diffusion-mediated cholesterol 'efflux' from cell surface. Cholesterol molecules desorbed from cells can be trapped by various extracellular acceptors including various lipoproteins and albumin, and extracellular cholesterol esterification mainly on HDL may provide a driving force for the net removal of cell cholesterol by maintaining a cholesterol gradient between lipoprotein surface and cell membrane. The other is apolipoprotein-mediated process to generate new HDL by removing cellular phospholipid and cholesterol. The reaction is initiated by the interaction of lipid-free or lipid-poor helical apolipoproteins with cellular surface resulting in assembly of HDL particles with cellular phospholipid and incorporation of cellular cholesterol into the HDL being formed. Thus, HDL has dual functions as an active cholesterol acceptor in the diffusion-mediated pathway and as an apolipoprotein carrier for the HDL assembly reaction. The impairment of the apolipoprotein-mediated reaction was found in Tangier disease and other familial HDL deficiencies to strongly suggest that this is a main mechanism to produce plasma HDL. The causative mutations for this defect was identified in ATP binding cassette transporter protein A1, as a significant step for further understanding of the reaction and cholesterol homeostasis. |
| Release of cholesterol from cell membranes to postprandial plasma from mildly hypercholesterolemic subjects: the effect of meals rich in olive and safflower oils Sutherland, W. H., S. A. De Jong, et al. (2002), Metabolism 51(10): 1306-12. Abstract: Triglyceride-rich lipoproteins increase net transport of cell cholesterol to postprandial plasma from healthy subjects after a meal rich in fat and cholesterol. The aim of the present study was to determine the effect of meals rich in polyunsaturated fats (PUFA) and monounsaturated fats (MUFA) and low in cholesterol on net in vitro transport of cholesterol from red blood cells (RBCs) to postprandial plasma from 21 men with mild to moderate hypercholesterolemia in a randomized, crossover trial. Cholesterol concentration increased by 12% due to accumulation of cell cholesterol in fasted hypercholesterolemic plasma incubated with a 2/1 (vol/vol) excess of RBCs at 37 degrees C for 18 hours. The increase in cell cholesterol in plasma was mainly localized in the low-density lipoprotein (LDL) fraction (64%) and the remainder was approximately equally divided between the very-low-density lipoprotein (VLDL) and high-density lipoprotein (HDL) fractions. Accumulation of cell cholesterol in the LDL fraction prevented the significant decrease in LDL cholesterol in plasma incubated alone. When RBCs were incubated with postprandial plasma isolated 4 hours and 6 hours after liquid meals rich in safflower and olive oils, the accumulation of cell cholesterol in plasma increased significantly (11%, P <.004) above values for fasted plasma and irrespective of the type of fat in the meal. Also, the content of cell cholesterol increased significantly (70%, P <.001) in triglyceride (TG)-rich lipoproteins and decreased significantly (P =.006) in the LDL fraction, which remained the main ultimate destination of cell cholesterol in postprandial plasma. The increased loss of cell cholesterol to fasted and postprandial plasma was closely correlated (r > 0.823, P <.001) with the concomitant increase in plasma cholesteryl esters (CE) generated by lecithin cholesterol acyltransferase (LCAT) activity. There was a small (5%), significant (P <.001) increase in plasma cholesterol esterification in postprandial plasma. These data suggest that high-fat meals rich in MUFA and PUFA and low in cholesterol may produce a small postprandial increase in the capacity of plasma to accept cell membrane cholesterol that is limited by a concomitant small increase in plasma cholesterol esterification, in hypercholesterolemic subjects. Thus, low-fat, lipid-lowering diets may have a minimal effect on this capacity but will reduce levels of atherogenic LDL cholesterol that appear to be maintained by diffusion of cell cholesterol to plasma. |
| Relevance of cholesterol screening in the United Arab Emirates. A preliminary study Agarwal, M. M., P. F. Hughes, et al. (1995), Eur J Epidemiol 11(5): 581-5. Abstract: The incidence of ischemic heart disease is rising rapidly in many of the affluent Arab countries and it is known that hypercholesterolemia is a well established risk factor for coronary artery disease. This community-based study was undertaken to determine if elevated cholesterol is a problem in the United Arab Emirates in order to be able to evaluate the contribution of cholesterol as a risk factor for atherosclerosis in this environment. Volunteers were recruited at busy urban public sites. Data on age, sex, nationality, weight, blood pressure and smoking history were collected, and blood samples were taken for estimation of total cholesterol, hemoglobin and individual blood group. A raw data set was developed, with calculation of body mass index and subsequent statistical analysis carried out on a PC using the SPSS programme. In the 834 patients, there were 19 nationalities represented which were pooled into 7 groups (5 Arab and 2 non Arab) according to their ethnic origins. The prevalence of hypercholesterolemia varied from 47.2-53% in the Arab Nationals and from 22.7 to 44.5% in the non Arabs. The mean cholesterol levels of the Arab subgroups were similar and showed no difference, statistically. However, they were significantly higher than non Arabs, i.e. Indians (p < 0.001) and Iranians (p < 0.001). Similarly, within the Arab subgroups, the median cholesterol levels were no different but were higher than the non Arabs, i.e. Indians (p < 0.05) and Iranians (p < 0.001). No statistical difference was found in the distribution of cholesterol (high, borderline high or desirable levels) among the seven ethnic groups. Hypercholesterolemia appears to be a problem in most nationalities living within the UAE. Overall, it afflicts nearly 50% of the adult population. Although the ethnic Arab groupings have a wide range of socioeconomic attributes, the similarity of the distribution of cholesterol may point to an underlying innate genetic etiology or an environmental cause such as dietary overindulgence, or both. Urgent public health measures such as education, case finding and further screening programs are required. |
| Relevance of hereditary defects in lipid transport proteins for the pathogenesis of cholesterol gallstone disease vanBerge-Henegouwen, G. P., N. G. Venneman, et al. (2004), Scand J Gastroenterol Suppl(241): 60-9. Abstract: In the formation of cholesterol gallstones, cholesterol hypersecretion into bile causing cholesterol supersaturation and crystallization appears to be the primary factor, with disturbed gallbladder and intestinal motility as secondary factors. Although intestinal uptake mechanisms have not yet been fully elucidated, the HDL receptor scavenger receptor B1 (SRB1) may be involved. Since HDL-cholesterol, both from the intestine and peripheral sources, is the preferred type of cholesterol for biliary secretion, increased HDL transport to the liver can also cause cholesterol hypersecretion in bile. In the hepatocyte, bile formation is regulated by several transmembrane proteins, all belonging to the ABC family. A change in the activity in one of these proteins can have a profound impact on biliary lipid secretion. The bile salt export pump (BSEP or ABCB11) regulates the excretion of bile salts into bile and mutations cause severe cholestasis. The second ABC transporter, ABCB4 (MDR3) regulates the secretion in bile of phosphatidylcholine (PC), while ABCG5/G8 is active in the excretion of cholesterol and sterols into bile. These transporters also facilitate transport of sterols back into the intestinal lumen. Mutations in either of these genes cause sitosterolaemia with increased absorption of plant sterols and cholesterol. Until now, evidence for a genetic background of human gallstone disease is mostly indirect and based on ethnic differences. Only two single gene defects are associated with gallstones. One is an ABCB4 mutation which causes a deficiency in biliary PC secretion and the other is a CYP7A1 mutation, the rate-limiting enzyme in the synthesis of bile salts from cholesterol in the liver. Recently, several common DNA polymorphisms in the ABCG8 gene were discovered that are associated with variations in plasma sterols, which could also influence biliary cholesterol secretion, but there is still a paucity of human studies. |
| Relevance of lipoprotein cholesterol levels measured by HPLC method to appearance midband on electrophoresis and remnant-like particle (RLP)-cholesterol levels Kurosawa, H., K. Doumitu, et al. (2004), Rinsho Byori 52(9): 737-41. Abstract: We have recently developed an HPLC method able to separate five lipoproteins (HDL, LDL, IDL, VLDL and chylomicron) followed by cholesterol measurement on each lipoprotein. As an application of this method, this study focused on analyses of triglyceride (TG)-rich lipoproteins, one of risk factor for atherosclerosis. The appearance of midband on electrophoresis is conceivably implicated in atherogenesis. The present study revealed that cholesterol levels in VLDL, IDL and LDL were significantly higher in midband-positive sera than negative sera. Cholesterol levels in remnant-like proteins, another atherogenic indicator, were significantly related to those in VLDL and Chylomicron measured by the present HPLC method. In conclusion, this novel HPLC method can provide valuable information for analyses on TG-rich lipoproteins. |
| Relevance of Niemann-Pick type C1 protein expression in controlling plasma cholesterol and biliary lipid secretion in mice Amigo, L., H. Mendoza, et al. (2002), Hepatology 36(4 Pt 1): 819-28. Abstract: Receptor-mediated endocytosis is one of the major mechanisms for uptake of lipoprotein cholesterol in the liver. Because Niemann-Pick C1 (NPC1) protein is a key component in the intracellular distribution of cholesterol obtained from lipoproteins by the endocytic pathway, it may play a critical role in controlling plasma lipoprotein cholesterol and its biliary secretion. A murine model of Niemann-Pick type C disease (NPC), the NPC1-deficient NPC1 (-/-) mouse, was used to evaluate the relevance of hepatic NPC1 expression in regulating plasma lipoprotein cholesterol profile and biliary lipid secretion under chow and high-cholesterol diets. Total plasma cholesterol concentrations were increased in NPC1 (-/-) mice compared with wild-type mice when both mouse strains were fed chow or high-cholesterol diets. The increased plasma cholesterol levels found in NPC1 (-/-) mice were mostly due to elevated cholesterol content in larger and more heterogeneous HDL particles. On the chow diet, biliary lipid secretion was not impaired by NPC1 deficiency. Furthermore, chow-fed NPC1 (-/-) mice showed a small, but significant, increase in biliary cholesterol secretion. On the high-cholesterol diet, wild-type mice increased biliary cholesterol output, whereas NPC1 (-/-) mice did not. Finally, hepatic NPC1 overexpression by adenovirus-mediated gene transfer increased biliary cholesterol secretion by 100% to 150% in both wild-type mice and cholesterol-fed NPC1 (-/-) mice. In conclusion, hepatic NPC1 expression is an important factor for regulating plasma HDL cholesterol levels and biliary cholesterol secretion in mice. |
| Reliability of the Reflotron in the determination of cholesterol Selmer, R., O. P. Foss, et al. (1990), Scand J Clin Lab Invest 50(3): 261-71. Abstract: Measurements of total cholesterol in the field by means of the Reflotron dry-chemistry system (capillary blood) were compared to total cholesterol obtained by a standardized conventional wet-chemistry method in a clinico-chemical laboratory (serum). A total of 1200 people participated in the study. Two identical Reflotron machines were used. In the first period of the study an excellent agreement was found between Reflotron measurements of a reference serum provided by the manufacturer (mean, 4.99 mmol/l; CV, 1.8%) and the stated value (4.97 mmol/l). In the rest of the study higher values and greater variation were found with the Reflotron (mean, 5.32 mmol/l; CV 5.2%). Clearly the Reflotron measurements in the latter period of study were not reliable. In the period with stable instruments most of the values obtained at the two Reflotron machines differed from each other by less than 10%, with a mean difference of 0.08 mmol/l. Reflotron (both machines) and wet-chemistry measurements agreed well for the first 500 participants in the study (mean difference, Reflotron-wet-chemistry, -0.008 mmol/l; 95% confidence interval, -0.035 to 0.019 mmol/l; correlation, 0.967). In this period most Reflotron values differed from wet-chemistry values by less than 9% below to 9% above. With the next 200 participants the Reflotron gave on average slightly higher values than wet-chemistry measurements. The coefficients of variation for measurement variation were higher for Reflotron that for wet-chemistry even in the period with stable instruments. In all parts of the study period a lower HDL-cholesterol level was associated with larger differences between total cholesterol determined by Reflotron and wet-chemistry. |
| Reliability of the Reflotron system for cholesterol determination Leinberger, R. and P. U. Koller (1991), Scand J Clin Lab Invest 51(3): 307. |