scholarly journals Determination of cholesterol in erythrocyte membrane

2003 ◽  
Vol 22 (3) ◽  
pp. 213-219
Author(s):  
Lidija Memon ◽  
Vesna Spasojevic-Kalimanovska ◽  
Pavle Jovic ◽  
Slavica Spasic ◽  
Natasa Bogavac-Stanojevic
Keyword(s):  
Risk Factors ◽  
Total Cholesterol ◽  
Erythrocyte Membrane ◽  
Ldl Cholesterol ◽  
Plasma Lipid ◽  
Cholesterol Concentration ◽  
Dry Extract ◽  
Blood Samples ◽  
Lipid Parameters

Quantification of cholesterol in biological membranes is an important step toward understanding of metabolism of intracellular cholesterol, composition of cell membrane and plasma lipid profile. The aim of our study was to optimize the method for determination of cholesterol in erythrocyte membrane and then to use this method in the determination of cholesterol concentration in erythrocyte membrane in the studied group of blood samples. Cholesterol in erythrocyte membrane was determined in dry lipid extract of erythrocyte membrane by the enzymatic manual CHOD-PAP method. Cholesterol in erythrocyte membrane and plasma lipid parameters (total cholesterol HDL-cholesterol, LDL-cholesterol and triglycerides) were determined in blood samples of 58 females, obtained by routine health control. Lipid parameters were determined by standard biochemical methods. We examined the relationship between cholesterol in erythrocyte membrane and other plasma lipid parameters as well as other atherogenic risk factors (BMI, blood pressure). Optimization of the method for determination of cholesterol in erythrocyte membrane was based on the observation that primary cholesterol standards prepared by dissolving crystal cholesterol cannot be used due to the interference of the dissolved dry extract in organic solvents with the enzymatic reagent. Commercial standard solutions of cholesterol were used for calibration because they contain detergents for solubilisation of the dry extract in enzymatic reagent. The obtained mean value for cholesterol in erythrocyte membrane, as mmol/L erythrocyte is 4.44 ? 1.019; median 4.65 5-th percentile is 2.70, and 95-th percentile is 6.26. In the examined female group we tested cholesterol concentration in erythrocyte membrane according to age. Two groups were formed (females below and above 50 years) using nonparametric t-test no statistically significant difference was found between these two age groups (p>0.05), while plasma lipid parameters of total cholesterol, triglycerides and LDL-cholesterol were different in the examined groups (p<0.05). By Spearmen nonparametric correlation method we found no statistically significant correlation between cholesterol in erythrocyte membrane and other atherogenic risk factors.

scholarly journals The assessment of risk factors, lipid profile, uric acid and alanine aminotransferase in Helicobacter pylori-positive subjects

2018 ◽  
Vol 6 (9) ◽  
pp. 2889 ◽  
Author(s):  
Martin Ernest Ndebi ◽  
Yvette Alvine Tonleu Guimtsop ◽  
Jean-de-Dieu Tamokou
Keyword(s):  
Risk Factors ◽  
Helicobacter Pylori ◽  
Uric Acid ◽  
Total Cholesterol ◽  
Alanine Aminotransferase ◽  
Ldl Cholesterol ◽  
Hdl Cholesterol ◽  
Enzyme Linked Immunosorbent Assay ◽  
H Pylori ◽  
Lipid Parameters

Background: Helicobacter pylori infection is associated with gastro duodenal ulcer, chronic gastric, MALT lymphoma and gastric cancer but also to coronary heart diseases, ischemic diseases and metabolic diseases like diabetes. The colonization of the stomach by H. pylori causes persistent inflammation of the stomach wall which can influence some biochemical parameters in the patient. The aim of this study was to investigate risk factors, uric acid and alanine aminotransferase along with lipid parameters in H. pylori-positive and -negative patients at Dschang District Hospital in Cameroon.Methods: A cross-sectional study was carried out on 160 consenting patients of average age 53.91±13.36 years attending the hospital for medical check-up or admitted in the hospital. The determination of anti-H. pylori IgG by the indirect enzyme-linked immunosorbent assay (ELISA) technique, enabled us to distinguish two groups of patients. A questionnaire survey was administered to study participants and potential risk factors for H. pylori exposure sought. Measurements of total cholesterol, HDL cholesterol, LDL cholesterol, triglycerides, uric acid and activity of alanine aminotransferase were carried out in serum by methods resulting from commercial kits.Results: The habits of not washing hands after the toilets (OR = 3.33; p = 0.036) and giving of chewed food by the parents to children (OR = 2.26; p = 0.029) were independent risk factors of H. pylori infection. H. pylori infected patients had increased levels of uric acid (p = 0.017), total cholesterol (p = 0.001), LDL-cholesterol (p = 0.021) and total cholesterol/HDL-cholesterol ratio (p = 0.046) compared to the uninfected group.Conclusions: Our study therefore suggests that H. pylori infection can cause modifications of lipid parameters and uremia that are considered as risk factors for cardiovascular diseases and gout. 

scholarly journals Cardiovascular Disease Risk Factors: How Relevant in African Men With Prostate Cancer Receiving Androgen-Deprivation Therapy?

2017 ◽  
Vol 3 (1) ◽  
pp. 7-14
Author(s):  
Okon Ekwere Essien ◽  
Iya Eze Bassey ◽  
Rebecca Mtaku Gali ◽  
Alphonsus Ekpe Udoh ◽  
Uwem Okon Akpan ◽  
...  
Keyword(s):  
Prostate Cancer ◽  
Risk Factors ◽  
Cardiovascular Disease ◽  
Cardiovascular Risk ◽  
Waist Circumference ◽  
Total Cholesterol ◽  
Ldl Cholesterol ◽  
Disease Risk ◽  
Cardiovascular Disease Risk ◽  
Treatment Naïve

Purpose Cardiovascular disease risk factors have been associated with androgen-deprivation therapy (ADT) in white and Hispanic populations. It is therefore relevant to determine if there exists a relationship between these parameters in the African population. Patients and Methods The design of the study was cross sectional. Prostate-specific antigen concentration, waist circumference, body mass index (BMI), lipid profile, glucose level, and insulin level were determined in 153 patients with prostate cancer and 80 controls. The patients with prostate cancer were divided into subgroups of treatment-naïve patients and those receiving ADT. Results Mean total cholesterol ( P = .010), LDL cholesterol ( P = .021), BMI ( P = .001), and waist circumference ( P = .029) values were significantly higher in patients treated with ADT when compared with treatment-naïve patients. In patients treated with ADT for up to 1 year, only mean BMI was significantly higher than in treatment-naïve patients, whereas those treated with ADT for more than 1 year had significantly higher mean BMI, waist circumference, total cholesterol, and LDL cholesterol values when compared with treatment-naïve patients. There were no significant differences in insulin or glucose levels. Those undergoing hormone manipulation after orchiectomy had fewer cardiovascular risk factors compared with those undergoing hormone manipulation alone. Conclusion This study shows that ADT results in elevated total cholesterol, LDL cholesterol, BMI, and waist circumference values, all of which are risk factors of cardiovascular disease. Screening for cardiovascular risk factors should be included in treatment plans for patients with prostate cancer.

Direct Fluorometric Determination of Total Cholesterol in Serum Using Derivatized Cholesterol Oxidase

2000 ◽  
Vol 54 (8) ◽  
pp. 1157-1162 ◽  
Author(s):  
Javier Galbán ◽  
José F. Sierra ◽  
José M. López Sebastian ◽  
Susana de Marcos ◽  
Juan R. Castillo
Keyword(s):  
Blood Serum ◽  
Total Cholesterol ◽  
Cholesterol Oxidase ◽  
Enzymatic Reaction ◽  
Direct Determination ◽  
Analytical Signal ◽  
Cholesterol Concentration ◽  
Serum Samples ◽  
Response Range

In this paper the use of cholesterol oxidase derivatized with a fluorescein derivative is proposed for the direct determination of total cholesterol in blood serum. The method is based on the changes in the fluorescence of the solution during the enzymatic reaction (λexe = 498 nm and λem 519 nm). A mathematical model which relates the analytical signal to the total cholesterol concentration was developed, and the model can also be used to obtain some of the thermodynamic constants of the process. The method has a linear response range up to 70 mg/L of cholesterol, a detection limit of 2.5 mg/L, and the precision was 1.0% (40 mg/L cholesterol, n = 10). The method was applied to total cholesterol determination in blood serum samples. The results were compared to those obtained by a commercial analyzer, and statistically similar results were obtained. The use of derivatized cholesterol oxidase makes it possible to simplify the methodology normally used in this type of determination (the indicator reaction is avoided and the number of reagents reduced), with the added advantage that the analytical signal is independent of the concentrations of O2 and cholesterol oxidase.

scholarly journals Validity of animal models for the cholesterol-raising effects of coffee diterpenes in human subjects

1999 ◽  
Vol 58 (3) ◽  
pp. 551-557 ◽  
Author(s):  
Baukje de Roos ◽  
Janet K. Sawyer ◽  
Martijn B. Katan ◽  
Lawrence L. Rudel
Keyword(s):  
Animal Model ◽  
Total Cholesterol ◽  
Mechanism Of Action ◽  
Serum Lipids ◽  
Animal Species ◽  
Ldl Cholesterol ◽  
Human Subjects ◽  
Plasma Lipoproteins ◽  
Cholesterol Concentration ◽  
Green Monkeys

Cafestol and kahweol, coffee lipids present in unfiltered coffee brews, potently increase LDL-cholesterol concentration in human subjects. We searched for an animal species in which cafestol similarly increases LDL-cholesterol. Such an animal model could be used subsequently as a model to study the mechanism of action of cafestol and kahweol. Cafestol and kahweol increased serum lipids in African green monkeys (Cercopithecus aethiops), cebus (Cebus apella) and rhesus (Macaca mulatta) monkeys, hamsters, rats and gerbils differently from the increase in human subjects. In African green monkeys, the rise in total cholesterol was less pronounced than that in human subjects. In addition, the increase in total cholesterol was predominantly due to a rise in HDL-cholesterol rather than LDL-cholesterol. Thus, the rise in plasma lipids might illustrate the mechanism in these monkeys rather than the mechanism in human subjects. In other animal species, cafestol and kahweol did not raise cholesterol consistently. The variability in effects on serum lipids could not be explained by the mode of administration or dose of diterpenes, nor by the amount of cholesterol in the diet. In conclusion, we did not find an animal model in which cafestol and kahweol elevate plasma lipoproteins to the same extent as in human subjects. For the time being, therefore, studies on the mechanism of action should be done preferably in human subjects.

scholarly journals Hypertriglyceridemia and Lower LDL Cholesterol Concentration in Relation to Apolipoprotein E Phenotypes in Myotonic Dystrophy

1989 ◽  
Vol 16 (1) ◽  
pp. 129-133 ◽  
Author(s):  
Sital Moorjani ◽  
Daniel Gaudet ◽  
Claude Laberge ◽  
Marie Christine Thibault ◽  
Jean Mathieu ◽  
...  
Keyword(s):  
Myotonic Dystrophy ◽  
Ldl Cholesterol ◽  
Plasma Cholesterol ◽  
Plasma Lipid ◽  
Cholesterol Concentration ◽  
Plasma Triglycerides ◽  
Ldl Particles ◽  
Vldl Cholesterol ◽  
Apo E

ABSTRACT:Plasma lipid, lipoprotein levels and apolipoprotein apo E phenotypes were determined in 70 patients with myotonic dystrophy (MyD) and 81 controls. Marked differences were noticed in the apo E phenotype frequencies between the two groups. Plasma triglycerides and VLDL cholesterol were higher in MyD than controls, but only the latter was related to differences in the apo E phenotypes between two groups. Accordingly, the ratio of VLDL cholesterol/plasma triglycerides was increased significantly in MyD, suggesting accumulation of intermediary density particles due to lower affinity of E2 containing lipoproteins for lipoprotein cell receptors. The LDL cholesterol concentration was lower in MyD than controls and was related to differences in the apo E phenotype frequencies between the two groups. These results indicate increased removal of LDL particles in the apo E2 phenotypes, perhaps due to upregulation of LDL (B, E) receptor activity. Plasma cholesterol and HDL cholesterol concentrations were similar in both groups. Another feature of the study was lower levels of plasma cholesterol, triglycerides, VLDL and LDL cholesterol in the homozygous E4:E4 phenotype. These results suggest increased clearance rate of both VLDL and LDL particles and support the concept that apo E4-containing lipoproteins have higher in vivo affinity for ape E and/or B, E receptors.

scholarly journals Determination of ionized magnesium in platelets and correlation with selected variables

1996 ◽  
Vol 42 (5) ◽  
pp. 744-748 ◽  
Author(s):  
J E Niemela ◽  
B M Snader ◽  
R J Elin
Keyword(s):  
Total Cholesterol ◽  
Inverse Correlation ◽  
Reference Interval ◽  
Cholesterol Concentration ◽  
Magnesium Concentration ◽  
Serum Electrolytes ◽  
Ionized Magnesium ◽  
And Gender ◽  
Dissociation Constant Kd

Abstract We describe a method for determining the intracellular ionized magnesium concentration ([Mg2+]i) in platelets by using the fluorescent probe FURAPTRA. We determined the dissociation constant (KD) of FURAPTRA for Mg2+ (2.26 +/- 0.29 mmol/L), within-day assay variability (CV = 6.8%), among-day intraindividual variability (CV = 11.0%), variability after a 4-h delay in processing the blood specimen (t = 1.2, P &gt;0.2; F = 6.2, P &lt;0.02), and the reference interval (0.23-0.59 mmol/L) for this assay. We also evaluated the correlation between platelet [Mg2+]i and concentrations of selected serum electrolytes, proteins, and total cholesterol; age; body mass index; and gender. Only the inverse correlation between platelet [Mg2+]i and serum total cholesterol concentration in men was significant (r=-0.66, P &lt;0.005).

Cardiovascular risk factors and endothelial dysfunction

2004 ◽  
Vol 107 (6) ◽  
pp. 609-615 ◽  
Author(s):  
Anthony S. WIERZBICKI ◽  
Philip J. CHOWIENCZYK ◽  
John R. COCKCROFT ◽  
Sally E. BRETT ◽  
Gerald F. WATTS ◽  
...  
Keyword(s):  
Risk Factors ◽  
Cardiovascular Risk ◽  
Endothelial Dysfunction ◽  
Ldl Cholesterol ◽  
Disease Risk ◽  
Absolute Risk ◽  
Density Lipoprotein ◽  
Cholesterol Concentration ◽  
Individual Risk ◽  
Multiple Risk Factor

Endothelial dysfunction is a feature of atherosclerosis and is associated with CHD (coronary heart disease) risk factors. This study aimed to determine the relationship between the degree of endothelial dysfunction and calculated cardiovascular risk. Endothelial function, as determined by the ACh/NP (acetycholine/sodium nitroprusside response) ratio on brachial plethysmography, was compared with cardiovascular risk as calculated from the Framingham, PROCAM (Prospective Cardiovascular Munster) and MRFIT (Multiple Risk Factor Intervention Trial) algorithms in 246 (187 male) patients, including 44 (22%) with established CHD. Endothelial dysfunction correlated with the total number of risk factors (r2=0.22; P=0.002) and was related to LDL (low-density lipoprotein)-cholesterol in men and triacylglycerols (triglycerides) in women. The ACh/NP ratio correlated with the occurrence of diabetes, CHD and the LDL-cholesterol concentration (r2=0.58; P<0.001). Endothelial dysfunction was associated with presence of CHD on receiver-operating characteristic plot analysis (area=0.706±0.04; P=0.001). There was no correlation between ACh/NP ratio and CHD risk calculated with the Framingham algorithm in men, although both ACh and NP response correlated separately with risk in women. The endothelial ACh/NP ratio correlated with absolute risk in the PROCAM algorithm (r2=0.41; P<0.005). Intermediate results were obtained with MRFIT. Individual risk factors make different contributions to endothelial dysfunction compared with their role in risk calculators. The stronger relationship of endothelial dysfunction with PROCAM risk reflects the contribution of male sex, LDL-cholesterol and triacylglycerols to risk calculated by this algorithm.

Effects of sample aging on total cholesterol values determined by the automated ferric chloride-sulfuric acid and Liebermann-Burchard procedures.

1980 ◽  
Vol 26 (5) ◽  
pp. 592-597 ◽  
Author(s):  
P D Wood ◽  
P S Bachorik ◽  
J J Albers ◽  
C C Stewart ◽  
C Winn ◽  
...  
Keyword(s):  
Sulfuric Acid ◽  
Total Cholesterol ◽  
Ferric Chloride ◽  
Continuous Flow ◽  
Frozen Storage ◽  
Cholesterol Concentration ◽  
Manual Method ◽  
Fresh Plasma ◽  
Sulfuric Acid Method

Abstract To investigate the comparability of three commonly used methods for determination of total cholesterol in plasma in several studies, we used fresh plasma samples as well as plasmas and reference sera that had been stored frozen at −15 degrees C for as long as several years. Duplicate determinations by the manual method of Abell et al. (J. Biol. Chem. 195: 357, 1952) were compared with estimates from one to five continuous-flow analyzers by the ferric chloride-sulfuric acid procedure and also with estimates from five to 13 continuous-flow analyzers by the Liebermann-Burchard procedure with calibrator, as part of the laboratory standardization activities of the Lipid Research Clinics. The agreement among all three procedures was generally within acceptable limits (within 5% of the manual method) when plasmas or sera were fresh or had been frozen for less than one month. Results by the manual method of Abell et al. agreed well with those by the automated Liebermann-Burchard method for samples that had been stored at −15 degrees C for as long as two years. However, the automated ferric chloride-sulfuric acid procedure often showed unacceptably high values (as compared with those from the manual method) for samples that had been stored frozen for a year or more. With the ferric chloride-sulfuric acid method, measured cholesterol concentration increased about 2.5% per year of storage for at least two years. We conclude that reference sera of plasmas that have been kept in long-term frozen storage (−15 degrees C) are not suitable for ongoing standardization of the automated ferric chloride-sulfuric acid assay for cholesterol.

scholarly journals Plasma lipid modifications in elderly people after administration of two virgin olive oils of the same variety (Olea europaeavar.hojiblanca) with different triacylglycerol composition

2003 ◽  
Vol 89 (6) ◽  
pp. 819-826 ◽  
Author(s):  
Javier S. Perona ◽  
Julio Cañizares ◽  
Emilio Montero ◽  
José M. Sánchez-Domínguez ◽  
Valentina Ruiz-Gutierrez
Keyword(s):  
Blood Pressure ◽  
Total Cholesterol ◽  
Ldl Cholesterol ◽  
Plasma Lipid ◽  
Cholesteryl Esters ◽  
Minor Components ◽  
Plasma Total Cholesterol ◽  
Virgin Olive Oils ◽  
Olive Oils ◽  
Triacylglycerol Molecular Species

In the present study we examined whether two virgin olive oils (VOO1 and VOO2), of the same variety (Olea europaeavar.hojiblanca) and with a similar composition of minor components but differing in the content of triacylglycerol molecular species, had different effects on blood pressure and plasma lipid levels in a healthy elderly population. Thirty-one participants, aged 84·9 (SD 6·4) years, were asked to participate in the study. No differences were found with regard to blood pressure after both experimental periods (VOO1 and VOO2). However, plasma total cholesterol and LDL-cholesterol were reduced only after VOO1 (P<0·01). The reduction of plasma cholesterol concentrations was related to the incorporation of oleic acid into plasma cholesteryl esters and phospholipids, which was higher after VOO1 (P<0·01). Indeed, the oleic acid concentration in cholesteryl esters and phospholipids strongly correlated with plasma total cholesterol and LDL-cholesterol levels in all experimental periods studied (r2>0·418,P<0·07), except for phospholipids in VOO1 (P=0·130 for total cholesterol andP=0·360 for LDL-cholesterol). These results have demonstrated that blood pressure and plasma lipids can be modified by the consumption of VOO in elderly people, but that the extent of such modification depends on the composition and amount of active minor components and triacylglycerol molecular species.

scholarly journals The lipoprotein/lipid profile is modulated by a gene–diet interaction effect between polymorphisms in the liver X receptor-α and dietary cholesterol intake in French-Canadians

2007 ◽  
Vol 97 (1) ◽  
pp. 11-18 ◽  
Author(s):  
Julie Robitaille ◽  
Alain Houde ◽  
Simone Lemieux ◽  
Daniel Gaudet ◽  
Louis Pérusse ◽  
...  
Keyword(s):  
Lipid Profile ◽  
Total Cholesterol ◽  
Ldl Cholesterol ◽  
Dietary Cholesterol ◽  
Plasma Lipid ◽  
Plasma Lipid Profile ◽  
Plasma Total Cholesterol ◽  
Lipoprotein Lipid ◽  
Liver X Receptor Α ◽  
Cholesterol Intake

Genetic and nutritional factors interact together and modulate the plasma lipid profile. We identified variations in the gene encoding the liver X receptor α (LXRα) and investigated their effects on the plasma lipoprotein/lipid profile. We also examined whether the association between cholesterol intake and plasma lipid profile was modulated by LXRα variants. The LXRα gene was sequenced in thirty-five French-Canadian men with high plasma total cholesterol (>5·0 mmol/l) and LDL-cholesterol (>3·5 mmol/l) concentrations. Dietary cholesterol was obtained from a food-frequency questionnaire. The LXRα c.-115G>A, c.-840C>A and c.-1830T>C genotypes were determined by direct sequencing in 732 subjects. Molecular screening of the LXRα gene revealed sixteen variants. Genotypes c.-115G>A, c.-840C>A and c.-1830T>C (rare allele frequency of 14·3 %, 14·2 % and 11·0 %, respectively) were analysed further. Plasma total cholesterol concentrations were higher in carriers of the -115A, -840A and -1830C allele, compared with the -115G/G, -840C/C and -1830T/T homozygotes (P ≤ 0·05). In a model including the c.-115G>A polymorphism, cholesterol intake, the interaction term c.-115G>A × cholesterol intake (mg/d) and covariates, LXRα-115G>A explained 1·8 % and 2·1 % of the variance in total cholesterol and LDL-cholesterol concentrations (P = 0·02 andP = 0·01), whereas the interaction term explained 2·9 % (P = 0·002) and 2·8 % (P = 0·005), respectively. When subjects were divided into four groups according to the median of cholesterol (290·8 mg) and -115G>A genotypes, high cholesterol intake was associated with higher cholesterol levels in -115A carriers. Similar results were observed for c.-840C>A and c.-1830T>C. These results suggest that cholesterol intake interacts with LXRα variants to modulate the plasma lipid profile.

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