Effect of liposome-encapsulated hemoglobin on triglyceride, total cholesterol, low-density lipoprotein, and high-density lipoprotein cholesterol measurements

The present study investigated the effect of liposome-encapsulated hemoglobin (LEH), an experimental oxygen-carrying resuscitation fluid, on triglyceride, total cholesterol, and low density lipoprotein (LDL), and high density lipoprotein (HDL) cholesterol measurements. In vivo, the intravenous infusion of LEH (5.6 mL/kg, n=6) elevated serum triglycerides (+92% vs. baseline, P<.05), total cholesterol (+25% vs. baseline, P<.01), LDL cholesterol (+72% vs. baseline, P<.01) and had no effect on serum HDL cholesterol. In addition, LEH did not alter the elevation in serum triglycerides (+302% vs. baseline, P<.01) and LDL cholesterol (+86% vs. baseline, P<.01) induced by lipopolysaccharide (3.6 mg/kg, i.v., n=6). Ex vivo, measurements of triglycerides and total cholesterol as well as LDL and HDL cholesterol in whole blood from naive rats were not changed by the addition of LEH (0–50%, n=6). In vitro, the addition of a fixed concentration of LEH (50%, n=6) to varying concentrations of cholesterol solution (0–50%), or vice versa, had no effect on cholesterol determination. It is therefore concluded that LEH only minimally affects serum levels of triglycerides, total cholesterol, LDL cholesterol, and HDL cholesterol and does not interfere with their measurement.     

Comparative study of methods for measuring cholesterol in biological fluids

A method combining enzymatic and electrochemical detection of cholesterol in biological fluids was compared with conventional detection methods: two chromatographic methods—gas chromatography or high performance liquid chromatography—and two enzymatic methods with colorimetric detection either by kinetic measurement or at the end of the reaction. For serum, enzymatic determination is accurate with both colorimetric detection methods; but for bile, colorimetric detection is difficult to perform due to interference from bile pigments. Enzymatic cholesterol determination, combined with electrochemical detection, is simpler and gives results in good agreement with those of chromatographic methods.     

Separation and chemical assay of lipide classes

Summary A survey is given of the micro determination of three major lipide classes: cholesterol, triglycerides, and phospholipides. The merits of a popular direct method for serum cholesterol and a system for rapid chromatographic separation of esterified cholesterol from other lipides have been discussed. Presented at the 49th annual meeting, American Oil Chemists' Society, Memphis, Tenn., April 22, 1958. This investigation was supported in part by a grant from the National Heart Institute, National Institutes of Health, United States Public Health Service (H-2181).     

荧光法测定鸡蛋中总胆固醇含量的研究

本研究建立了一种荧光法测定鸡蛋中总胆固醇含量的新方法。在浓硫酸的催化作用下,邻苯二甲醛与胆固醇反应后生成一种紫红色物质,该物质在340 nm激发条件下,于550 nm处产生明显的荧光发射光谱,利用该荧光光谱可检测鸡蛋中总胆固醇的含量。本实验探讨了胆固醇荧光光谱的测定条件,在确定的优化条件下,胆固醇浓度在0~0.1664 mg/μL的范围内呈良好的线性关系,最低检测限(LOD)为0.011 mg/μL。该检测方法操作简单,准确度高,重现性好,结果可靠,可广泛用于实验研究和生产过程中胆固醇的检测。     

Quantification of lowered cholesterol oxidation in guinea pigs with latent vitamin C deficiency

Fifty-two male guinea pigs fed on a scorbutigenic diet were divided into a control group (10 mg ascorbicacid per animal per day) and a group with latent vitamin C deficiency (2 weeks on the scorbutigenic diet only, followed by a maintaining dose of 0.5 mg ascorbic acid per animal per day). After 13 weeks, 26-¹⁴C-cholesterol was administered intraperitoneally to all the animals, in which the¹⁴C excretion in the expired CO₂ and the urine and cholesterol specific activity in the blood serum and liver were then studied at intervals of 24 hr and 1, 3, 5, 7, 9 and 11 weeks. The ascorbic acid concentration in the liver and spleen of the control animals was five times higher than in vitain C-deficient animals. The total cholesterol concentration in serum and liver was significantly higher in the vitamin C-deficient guinea pigs. A two-pool analysis of the disappearance curves of serum cholesterol specific activity showed that the size of the cholesterol pool A (blood and tissues with rapid cholesterol exchange) was greater in the vitamin C-deficient animals. The rate of the transformation of cholesterol to bile acids was estimated as the ratio of¹⁴CO₂ expired to liver cholesterol specific activity. Latent vitamin C deficiency caused significant slowing down of this process (controls: 11.8±0.6; vitamin C deficiency: 8.3±0.4 mg/24 r/500 g w/w). A significant correlation between the liver ascorbic acid concentration and the rate of cholesterol transformation to bile acids was found. The results demonstrate that ascorbic acid is necessary for a normal course of cholesterol catabolism. In latent vitamin C deficiency, the rate of cholesterol catabolism slows down and cholesterol consequently accumulates in the blood and liver of vitamin C-deficient guinea pigs.     

Changes in blood lipids and fibrinogen with a note on safety in a long term study on the effects of n−3 fatty acids in subjects receiving fish oil supplements and followed for seven years

The present study was designed to assess the effectiveness of the n−3 fatty acids in modifying serum total, low density lipoprotein and high density lipoprotein (HDL) cholesterol, as well as serum triglycerides, over a seven-year period. Changes in plasma fibrinogen were recorded and long term safety assessed. A total of 365 subjects with ischemic heart disease (IHD), hyperlipidemia or a strong family history of IHD had their diet supplemented with MaxEPA (Seven Seas Ltd., Hull, England) fish oil containing 18–19% eicosapentaenoic acid. Venous blood samples were taken at regular intervals for lipid and fibrinogen assays and routine clinical chemistry and hematological profiling. Current medication was recorded and no further dietary modification was attempted. Triglyceride and fibrinogen were significantly reduced, whereas a significant reduction in total cholesterol occurred only in the subjects with a pre-oil level>6.5 mmol/L. HDL cholesterol significantly increased over the study period. Clinical chemistry and hematological profiles were not adversely affected, and platelet count did not change significantly. The type of lipid changes observed were those usually considered antiatherogenic. Reducing fibrinogen may result in beneficial changes in the pathological processes leading to thrombotic occlusion. The consumption of MaxEPA by our patients over a seven-year period did not indicate any adverse effects.     

Electrochemical oxidation of cholesterol in acetonitrile leads to the formation of cholesta-4,6-dien-3-one

Cholesterol was shown to be oxidized at the glassy carbon electrode in an acetonitrile–2-propanol mixture and this oxidation reaction was applied to the determination of serum total cholesterol by high-performance liquid chromatography with electrochemical detection (K. Hojo, H. Hakamata, A. Ito, A. Kotani, C. Furukawa, Y.Y. Hosokawa, F. Kusu, J. Chromatogr. A 1166 (2007) 135–141). To gain insight into the detection mechanisms of cholesterol, an electrolytic product of cholesterol was collected and characterized by infrared spectroscopy, one- and two-dimensional nuclear magnetic resonance, and matrix-assisted laser desorption/ionization time-of-flight mass spectrometry. The three techniques, together with comparisons of literature spectral data, confirmed the formation of cholesta-4,6-dien-3-one. The conversion of cholesterol to cholesta-4,6-dien-3-one, a four-electron, four-proton electrochemical process, has been proposed as an electrochemical oxidation mechanism of cholesterol in acetonitrile.     

A simplified colorimetric micromethod for determination of serum cholesterol

A simple and rapid micromethod is described for quantitation of cholesterol in 5–10 μl of serum using uranyl acetate to deproteinize the serum ando-phthalaldehyde reagent to develop color. Independent analyses of serum samples by the present method and by two reference methods, Abell-Kendall and automated colorimetric method, indicated accuracy of the micromethod (r=0.99). Use of capillary blood specimens makes this procedure applicable for screening infants and small children.     

Effect of a new fermented soy milk product on serum lipid levels in normocholesterolemic adult men

This study was undertaken to verify the effect of a daily intake of a new fermented soy milk produced with Enterococcus faecium and Lactobacillus jugurti on the serum lipid levels in normocholesterolemic middle-aged men. The study was randomized, double-blind and placebo-controlled and was performed for a period of 6 weeks. Forty-four normocholesterolemic healthy, male volunteers, aged 40-55 years old were randomly separated in two groups: The F-group received 200 ml of the fermented product daily and the P-group received 200 ml of placebo (chemically fermented). The blood samples were drawn initially and after 3 and 6 weeks and serum values for total cholesterol, HDL-cholesterol and triglyceride were determined. The LDL-cholesterol value was estimated. No significant changes in the fermented group (F) were observed for total cholesterol, LDL-cholesterol or triglyceride levels, while the HDL-cholesterol level was significantly higher (p < or = 0.05) after 6 weeks. The total cholesterol and LDL-cholesterol levels were significantly higher (p < or = 0.05) in the placebo group (P), but no changes were found for the HDL-cholesterol and triglyceride levels during the experimental period. In conclusion, the intake of 200 ml/day of the fermented soy milk, produced with E. faecium and L. jugurti, for 6 weeks, did not affect the serum total cholesterol and LDL-cholesterol, and led an increase of 10% in the HDL-cholesterol level.     

Microplate methods for determination of serum cholesterol,high density lipoprotein cholesterol,triglyceride and apolipoproteins

Microtiter plate methods were developed for the enzymatic determination of serum total cholesterol (TC), high density lipoprotein cholesterol (HDL-C) and triglyceride (TG), and for the turbidometric determination of apolipoproteins. The micromethods resulted in accurate, precise values that were in good agreement with the conventional spectrophotometric assays. The coefficient of variation for TC determinations was 4.5% or less and bias was 5% or less. The lipid micromethod assays are sensitive to 10 mg/dL or less, and the apolipoprotein assay to 1 mg/dL. Less than 100 μL of serum suffices for TC, TG and apoprotein assays; HDL-C requires an additional 100 μL of serum. Advantages of the micromethods include reductions in assay time and in the amount of reagents required.     

Acidic Polysaccharide Extracts from Gastrodia Rhizomes Suppress the Atherosclerosis Risk Index through Inhibition of the Serum Cholesterol Composition in Sprague Dawley Rats Fed a High-Fat Diet

Obesity is associated with a broad spectrum of cardio-metabolic disturbances, including atherosclerosis and cardiovascular disease (CDV). A high-fat diet has been shown to cause an elevation of the plasma cholesterol levels in humans, and the control of serum cholesterol has been demonstrated to be important in the prevention of CVD and atherosclerosis. The aims of this study were to demonstrate that crude and acidic polysaccharide extracts from Gastrodia rhizomes suppress atherosclerosis through the regulation of serum lipids in Sprague Dawley (SD) rats fed a high-fat diet. We examined the concentrations of serum lipids, including total cholesterol, triglycerides, high-density lipoproteins (HDL) cholesterol, and low-density lipoproteins (LDL) cholesterol, in SD rats fed a high-fat diet and evaluated the atherogenic index. Here, we show that both crude and acidic polysaccharide extracts from Gastrodia rhizomes inhibited the total cholesterol and LDL levels. Moreover, there was a significantly suppressed atherosclerosis risk due to the acidic polysaccharide extract from Gastrodia rhizome. Taken together, our results suggested that acidic polysaccharide extracts from Gastrodia rhizomes might be beneficial for lowering the incidence of CVD and atherosclerosis by reducing the de novo synthesis of total cholesterol and the LDL levels.     

Plasma cholesterol turnover and esterification in the pigeon

The plasma cholesterol turnover and serum cholesterol esterifying system was studied in White Carneau pigeons. Eight pigeons received a single injection of 1,2-³H-cholesterol intravenously and the decline in plasma cholesterol specific activity was measured at intervals from 1–64 days. Kinetic analysis of the plasma cholesterol die-away curves indicates that plasma cholesterol turnover in the pigeon conforms to a 2 pool model. The mass of pool A (cholesterol in blood and those tissues which are rapidly equilibrated with blood) in pigeons maintaining consistently high serum cholesterol levels (≈900 mg/100 ml) was 988 mg and the daily fractional turnover of pool A was 19.7% compared with 676 mg and 12.2% found in pigeons maintaining consistently low (≈400 mg/100 ml) serum cholesterol levels. Serum cholesterol esterifying activity, in vitro, showed a positive correlation (rxy=0.806) with serum cholesterol concentration in the pigeon. The pigeon differs, in this regard, from the chicken, rat and rabbit in which a negative correlation has been reported.     

Potassium-doped carbon nanotubes toward the direct electrochemistry of cholesterol oxidase and its application in highly sensitive cholesterol biosensor

We demonstrate herein a newly developed serum total cholesterol biosensor by using the direct electron transfer of cholesterol oxidase (ChOx), which is based on the immobilization of cholesterol oxidase and cholesterol esterase (ChEt) on potassium-doped multi-walled carbon nanotubes (KMWNTs) modified electrodes. The KMWNTs accelerate the electron transfer from electrode surface to the immobilized ChOx, achieving the direct electrochemistry of ChOx and maintaining its bioactivity. As a new platform in cholesterol analysis, the resulting electrode (ChOx/KMWNTs/GCE) exhibits a sensitive response to free cholesterol, with a linear range of 0.050–16.0 μmol L⁻¹ and a detection limit of 5.0 nmol L⁻¹ (S/N = 3). Coimmobilization of ChEt and ChOx (ChEt/ChOx/KMWNTs/GCE) allows the determination of both free cholesterol and esterified cholesterol. The resulting biosensor shows the same linear range of 0.050–16.0 μmol L⁻¹ for free cholesterol and cholesteryl oleate, with the detection limit of 10.0 and 12.0 nmol L⁻¹ (S/N = 3), respectively. The concentrations of total (free and esterified) cholesterol in human serum samples, determined by using the techniques developed in the present study, are in good agreement with those determined by the well-established techniques using the spectrophotometry.     

Gesamt-, HDL- und LDL-Cholesterinbestimmung im Serum von Ratten- Vergleich einiger Methoden mit der Ultrazentrifugation

Total Cholesterol, HDL- and LDL-Cholesterol in Rat Serum - Estimated with Different Methods in Comparison to the Ultracentrifugation Different methods for the estimation of total cholesterol, HDL- and LDL-cholesterol were carried out in rat serum. Their applicability considering precision, accuracy, practicability and susceptibility to disturbances was compared with the ultracentrifugation as a reference method. The analyses were carried out in serum of male Wistar rats fed isoenergetic diets containing no cholesterol or supplemented with 1 % cholesterol. Results of total cholesterol estimations using the CHOD-PAP method were in agreement with those of the CHOD-JODID assay. Using the precipitation method with tungstic acid and MgCl₂ the HDL-cholesterol values correlated with the reference method closer than those with the heparin-MgCl₂-precipitation method. The results of LDL-cholesterol estimations in rat serum using both precipitation methods were not satisfactory. For this purpose only the ultracentrifugation method can be recommended.     

A long-term seal- and cod-liver-oil supplementation in hypercholesterolemic subjects

In this long-term study, we wanted to explore the effect of dietary supplementation of seal oil (SO) as compared cod-liver oil (CLO) on subjects with moderate hypercholesterolemia. The test parameters included fatty acid composition in serum, blood lipids, platelet aggregation, and the activity of blood monocytes. After a run-in period of 6 mon, 120 clinically healthy hypercholesterolemic (7.0–9.5 mmol/L; 270–366 mg/dL) subjects were randomly selected to consume either 15 mL of SO or CLO daily for 14 mon followed by a 4-mon wash-out period. A third group was not given any dietary supplement (control). Consumption of marine oils (SO and CLO) changed the fatty acid composition of serum significantly. Maximal levels were achieved after 10 mon. No further changes were seen after 14 mon. A wash-out period of 4 mon hardly altered the level of n−3 fatty acids in serum. Addition of SO gave 30% higher level of eicosapentaenoic acid, as compared to CLO. Subjects taking SO or CLO had lower whole-blood platelet aggregation than the control group. Neither SO nor CLO had any effects on the levels of serum total cholesterol, high-density lipoprotein cholesterol, postprandial triacylglycerol, apolipoproteins A1 and B100, lipoprotein (a), monocyte function expressed as monocyte-derived tissue factor expression, and tumor necrosis factor.     

Cholesterinbestimmung in β-Lipoproteinen

Determination of Cholesterol in β-Lipoproteins Recent studies have shown that cholesterol synthesis is regulated by apolipoprotein B, the main apolipoprotein of the β-lipoprotein fraction. Since the customary differentiation of a hyperlipoproteinaemia type II is based on the determination of cholesterol concentration in β-lipoprotein, and, since little studies are known on the apolipoprotein-B content of serum LDL-fraction, a comparative investigation was carried out on 500 normolipaemics and hyperlipoproteinaemics (type IIa, lib, IV). In the sera of patients, the cholesterol content of β-lipoprotein was determined by ultracentrifugation and apolipoprotein-B content was determined by the radial immunodiffusion technique. It was found that in the sera of type II patients the total apo-B content and the LDL-apo-B content of the serum is significantly higher compared to type IV patients and normolipaemics. In addition, the ratio of β-cholesterin to LDL apo-B is moved to higher values. In the group of normolipaemics, an age-dependent alteration of apolipoprotein-B content in serum was found. The results are discussed with respect to their physiological and diagnostic significance.     

Effects of dressing containing plant sterol on serum cholesterol concentration and the safety evaluation in borderline or mildly hypercholesterolemic Japanese subjects

In a placebo-controlled double-blind study, we examined the effects of dressing containing plant sterol (PS) on blood lipids and the safety in Japanese borderline or mildly hypercholesterolemic subjects. Fifty-nine subjects [total cholesterol (TC) concentration > or = 200 mg/dL] were randomly divided into two groups and were given daily 15 g of dressing containing 800 mg of PS [PS(+)-group] or without PS [PS(-)-group] for 12 weeks. Every 4 weeks, fasting blood was examined and subjective symptoms were analyzed. Serum TC, low-density lipoprotein cholesterol (LDL-C) and apolipoprotein B (ApoB) concentrations did not change in the PS(-)-group, while TC and ApoB significantly decreased in the PS(+)-group at 8 and 12 weeks and LDL-C at 4, 8 and 12 weeks. Moreover, serum TC, LDL-C and ApoB concentrations were significantly lower than those of PS(-)-group at 8 and 12 weeks. Other laboratory tests were all in normal ranges and no adverse events were observed. The results indicated that PS-containing dressing decreased serum TC, LDL-C and ApoB concentrations in borderline or mildly hypercholesterolemic subjects. It is therefore proved that the dressing containing PS is helpful in maintaining blood cholesterol level normal and hence, the health of Japanese.     

Development of a Cholesterol Biosensor by Chronoamperometric Deposition of Polyaniline-Ag Nanocomposites

Chronoamperometry was employed to prepare polyaniline-p-toluene sulphonic acid-silver (PANI-pTSA-Ag) nanocomposite film on indium tin oxide–coated glass plate to fabricate a cholesterol bioelectrode. The authors observed the high sensitivity of 36.3 µA/mg/dL with a fast response time of 10 s in the range of 20–400 mg/dL for the bioelectrode. The bioelectrode exhibits uniform activity for 50 days under refrigerated conditions. Attempts have been made to utilize this bioelectrode for estimation of total cholesterol in blood serum samples.     

Selective gas chromatographic determination of cholesterol in eggs

A selective gas-chromatographic method is proposed for the determination of cholesterol in egg samples. The method consists of extraction of the lipid fraction and cold saponification prior to determination on a glass capillary column. The absence of cholesterol oxidation during the process was checked, and the conditions in which oxidation is avoided are discussed. The method also showed good precision (coefficient of variation=1.39%). Applying this method to different fresh and frozen egg samples, we obtained a mean content of 392 mg of cholesterol/100 g of edible portion. These values are clearly lower than the majority of results published for eggs.     

The effect of dietary supplementation of cholesterol and its subsequent withdrawal on the liver lipids and serum lipoproteins of chickens

Two groups of male chickens were fed either a control diet (group N) containing a standard poultry ration admixed with 10% corn oil or a cholesterol diet (group C) in which the control diet was supplemented with 1% cholesterol. After 6 weeks on the diets, a negligible amount of very low density lipoprotein (VLDL) was found in the serum from control animals. On the other hand, the serum VLDL from the cholesterol-fed birds was the predominant lipoprotein and carried 72% of the total serum lipids. Surprisingly this lipoprotein from cholesterol-fed animals was very low in triglycrides (6%) and high in total cholesterol (77%). While the level of serum low density liporotein was unaffected by the ingestion of cholesterol, the concentration of total lipids and phospholipids in the high density lipoprotein decreased in cholesterol-fed animals. The greatest change in liver lipids from animals fed cholesterol was found in the cholesterol esters, whereas the unesterified cholesterol, triglyceride and phospholipid varied slightly or remained constant. In normal animals the distribution of cholesterol between the liver and the serum was about equal, whereas in the cholesterol-fed birds the liver accounted for 80% of the cholesterol found in the liver-serum pool. In order to determine how the hypercholesterolemic bird responds to the withdrawal of cholesterol from the ration, a diet-exchange experiment was conducted. In this study the birds that were originally fed the cholesterol diets (group C) for 6 weeks were placed on the control diet (group CN) and the birds fed the control diet (group N) for 6 weeks were given the cholesterol diet (group NC). At periodic intervals, 1, 3, 7 and 14 days following the change of diets, 3–5 animals from each group were sacrificed, and analyses performed on their serum lipoproteins and liver lipids. Within one day after the diet substitution, there was a 31-fold increase and a 46% decrease, respectively, in the serum VLDL concentration in groups NC and CN as compared with their corresponding steady state values (groups N and group C, respectively). The liver cholesterol increased 4-fold and decreased 40%, respectively, in the two groups NC and CN as compared with the values obtained before the diet substitution. It is suggested that the concentration of cholesterol in the liver is the principal factor controlling cholesterol metabolism in chickens fed a hypercholesterolemic diet. This represents a portion of a Ph.D. thesis submitted by A.W. Kruski to the University of Illinois in February 1971.