Enzymic assay of total cholesterol involving chemical or enzymic hydrolysis--a comparison of methods.

1979 ◽  
Vol 25 (6) ◽  
pp. 976-984 ◽  
Author(s):  
A C Deacon ◽  
P J Dawson
Keyword(s):  
Total Cholesterol ◽  
Potassium Hydroxide ◽  
Cholesterol Oxidase ◽  
Cholesterol Concentration ◽  
Cholesteryl Esters ◽  
Enzymic Hydrolysis ◽  
Hydrolysis Method ◽  
Chemical Hydrolysis ◽  
Incomplete Removal ◽  
Enzymic Assay

Abstract Manual procedures for estimating serum total cholesterol by use of cholesterol oxidase (EC 1.1.3.6) and the phenol--aminophenazone--peroxidase chromogenic system are described, in which cholesteryl esters are hydrolyzed either by use of pancreatic cholesterol ester hydrolase (EC 3.1.1.13) or saponification by ethanolic potassium hydroxide. Both methods are linear up to a cholesterol concentration of 12 mmol/L and are reproducible (between-run CV, about 1.1%). The chemical hydrolysis method yields results that are about 10% lower than those obtained by enzymic hydrolysis, because of incomplete removal of interfering thiols generated during the saponification of serum. The chemical hydrolysis procedure is much less susceptible to interferences, particularly by bilirubin, but the enzymic hydrolysis system is simpler to perform and therefore has a greater potential for mechanization.

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.

Kinetic enzymic method for automated determination of total cholesterol in serum.

1983 ◽  
Vol 29 (10) ◽  
pp. 1798-1802 ◽  
Author(s):  
R Deeg ◽  
J Ziegenhorn
Keyword(s):  
Total Cholesterol ◽  
Incubation Temperature ◽  
Cholesterol Oxidase ◽  
Fixed Time ◽  
Competitive Inhibitor ◽  
Cholesterol Concentration ◽  
Total Analysis ◽  
Single Standard ◽  
Automated Determination

Abstract We describe a rapid, kinetic, fixed-time method for determining serum total cholesterol by use of cholesterol esterase, cholesterol oxidase, and the indicator reaction with peroxidase, 4-aminophenazone, and phenol. On addition of the competitive inhibitor 3,4-dichlorophenol the Michaelis constant of cholesterol oxidase is apparently increased, which extends the linear relation between absorbance change and cholesterol concentration to 20.7 to 25.9 mmol/L, depending on the analyzer being used. For calibration, a single standard is used. Total analysis time is in the range of 80 to 210 s. Incubation temperature is 25 degrees C or 37 degrees C. The single-reagent procedure has been adapted to three different centrifugal analyzers and to the Eppendorf ACP 5040 analyzer. It yields precise and accurate results and is insensitive to potential interferences.

scholarly journals Effect on lipid profile due to prolong Valproic acid intake

2021 ◽  
Vol 15 (7) ◽  
pp. 1497-1499
Author(s):  
Rao. S Aziz ◽  
Usman Saeed ◽  
Liaqat Ali ◽  
Muhammad Arshad ◽  
Roman Abbas ◽  
...  
Keyword(s):  
Valproic Acid ◽  
Lipid Profile ◽  
Total Cholesterol ◽  
Cholesterol Oxidase ◽  
Venous Blood ◽  
Case Group ◽  
Long Duration ◽  
And Control ◽  
Relationship Of

Background: Valproic acid (VA) serve as the antimigraine , anti-mental disturbances agent and antiepileptic medicine. After using va, metabolic rearrangements seen in patients that include alteration in lipoproteins levels; Aim: To discuss the effects of VA after using for long duration on total levels of cholesterol in adult. Methods: About Eighty candidates participated and they were divided into two groups namely, case group (40 candidates) and control groups (40 candidates). All the candidates were asked for collection of venous blood sample in order to determine total cholesterol serum level among them via aid of enzymatic cholesterol oxidase phenol 4-aminoantipyrine peroxidase. Results: By the aid of the logistic regression analysis, the relationship of the long-term VA treatment and the level of total cholesterol was obtained. With respect to our analysis, there is a co relation between total levels of cholestrol and long term usage of VA (P=0.003). Conclusions: In a net shell, by using VA for long duration, the total level of cholesterol in adults reduces. Keywords: Lipid profile, side effects, total cholesterol, valproic acid

scholarly journals Effect of chitin and chitosan on nutrient digestibility and plasma lipid concentrations in broiler chickens

1994 ◽  
Vol 72 (2) ◽  
pp. 277-288 ◽  
Author(s):  
A. Razdan ◽  
D. Pettersson
Keyword(s):  
Total Cholesterol ◽  
Broiler Chickens ◽  
Control Diet ◽  
Nutrient Digestibility ◽  
Dietary Fats ◽  
Cholesterol Concentration ◽  
Free Access ◽  
Intestinal Transit Time ◽  
Cholesterol Ratio ◽  
Plasma Triacylglycerol

Broiler chickens were fed on a control diet based on maize and maize starch or diets containing chitin, or 94, 82 or 76% deacetylated chitin (chitosans) with different viscosities (360, 590 and 620 m Pa.s respectively) at an inclusion level of 30 g/kg. Animals had free access to feed and water for the whole experimental period. On days 10 and 18 of the experiment chickens given the control and chitin-containing diets weighed more, had consumed more feed and had lower feed conversion ratios (g feed/g weight gain) than chitosan-fed birds. Feeding of chitosan-containing diets generally reduced total plasma cholesterol and high-density-lipoprotein (HDL)-cholesterol concentrations and gave an increased HDL:total cholesterol ratio in comparison with chickens given the control and chitin-containing diets. However, no significant reductions in plasma triacylglycerol concentrations resulting from feeding of the chitosan-containing diets were observed. The reduction in total cholesterol concentration and increased HDL: total cholesterol ratio were probably caused by enhanced reverse cholesterol transport in response to intestinal losses of dietary fats. The suggestion that dietary fat absorption was impeded by the chitosans was strengthened by the observation that ileal fat digestibility was reduced by 26% in comparison with control and chitin-fed animals. In a plasma triacylglycerol response study on day 21, feeding of 94 and 76%-chitosan-containing diets generally reduced postprandial triacylglycerol concentrations compared with chickens given the chitin-containing diet. Duodenal digestibilities of nutrients amongst chickens given the chitin-containing diet were generally lower than those of control and chitosan-fed birds indicating decreased intestinal transit time. The reduced caecal short-chain fatty acid concentrations of chickens given chitosan diets compared with the control diet illustrates the antimicrobial nature of chitosan. The fact that the three chitosan-containing diets affected the registered variables similarly indicated that the level of inclusion of chitosans in the diet exceeded the level at which the effect of the different viscosities could be significant.

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 Highly Sensitive Cholesterol Assay with Enzymatic Cycling Applied to Measurement of Remnant Lipoprotein-Cholesterol in Serum

2002 ◽  
Vol 48 (5) ◽  
pp. 737-741 ◽  
Author(s):  
Koji Kishi ◽  
Koji Ochiai ◽  
Yohsuke Ohta ◽  
Yahiro Uemura ◽  
Kazushi Kanatani ◽  
...  
Keyword(s):  
Cholesterol Oxidase ◽  
Lipoprotein Cholesterol ◽  
Cholesterol Concentration ◽  
Separation Procedure ◽  
Enzymatic Method ◽  
Healthy Individuals ◽  
Apo B ◽  
Remnant Lipoprotein ◽  
Enzymatic Cycling ◽  
Highly Sensitive

Abstract Background: Remnant lipoprotein-cholesterol (RLP-C) concentrations in sera of healthy individuals are very low (0.080–0.437 mmol/L), making conventional cholesterol methods poorly suited to this purpose. We have developed a highly sensitive cholesterol assay (CD method) and applied it to the RLP-C assay. Methods: The CD shuttled cholesterol reversibly between reduced and oxidized forms in the presence of thio-NAD and NADH. The production rate of thio-NADH correlated with the cholesterol concentration and was measured by the absorbance at 404/500 nm. This CD method was combined with an immunoaffinity separation procedure with specific monoclonal antibodies to apolipoprotein (apo) A1 and apo B-100 and used for RLP-C assay. Results were compared with a RLP-C method that uses cholesterol oxidase, peroxidase, and chromogenic substrate. Results: The CD method could detect 0.10 × 10−3 mmol/L cholesterol and was at least 5 times more sensitive than the conventional enzymatic method. Within- and between-day imprecision (as CVs) of the RLP-C assay with the CD method was <4%. Regression analysis of RLP-C assays with the new (y) and conventional (x) cholesterol methods yielded: y = 1.02x − 0.008 mmol/L (Sy|x = 0.0065 mmol/L; r = 0.997; n = 297). Conclusions: Serum RLP-C can be measured by the CD method. The CD method may be useful for other assays that require sensitive cholesterol measurements in biological materials.

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