The measurement of high-density lipoprotein mediated cholesterol efflux from macrophage cells by liquid chromatography tandem mass spectrometry.

Background: Studies have shown a negative association between macrophage cholesterol efflux and atherosclerotic cardiovascular diseases (CVD). However, the current methods for measuring cholesterol efflux require a radioactive tracer and involve a variety of cell treatments, making the measurement of macrophage cholesterol efflux impractical for use in clinical laboratories. In this study, we developed a non-radioactive and precise LC/MS/MS method for the measurement of high-density lipoprotein (HDL) mediated cholesterol efflux from J774 macrophages.

Association of branched-chain amino acids with carotid intima-media thickness and coronary artery disease risk factors.

Background: Recent studies have determined that branched-chain (BCAAs) and aromatic (AAAs) amino acids are strongly correlated with obesity and atherogenic dyslipidemia and are strong predictors of diabetes. However, it is not clear if these amino acids are capable of identifying subjects with coronary artery disease (CAD), particularly with subclinical atherosclerosis who are at risk of developing CAD.

Methods: Four hundred and seventy two Chinese subjects (272 males and 200 females, 42-97 y of age) undergoing physical exams were recruited at random for participation in the cross-sectional study.

A rapid and precise method for quantification of fatty acids in human serum cholesteryl esters by liquid chromatography and tandem mass spectrometry.

We described a rapid and precise method for simultaneous quantification of eleven fatty acids in human serum cholesteryl esters (CEFAs) by liquid chromatography and tandem mass spectrometry (LC-MS/MS). After extraction of serum lipids with isopropanol, CEFAs were separated on reversed phase liquid chromatography and detected by mass spectrometry in positive ion mode with multiple reaction monitor. Individual CEFA was quantified by peak area normalization method and expressed as molar percent of total CEFAs.

Rapid and precise measurement of serum branched-chain and aromatic amino acids by isotope dilution liquid chromatography tandem mass spectrometry.

Background: Serum branched-chain and aromatic amino acids (BCAAs and AAAs) have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming.

Methods: An isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS) method for serum BCAAs and AAAs was developed.

A simple and precise method for direct measurement of fractional esterification rate of high density lipoprotein cholesterol by high performance liquid chromatography.

Background: The relationship between fractional cholesterol esterification rate in plasma or serum high-density lipoprotein (HDL) (FER(HDL)) and lipoprotein subfractions and other cardiovascular disease (CVD) risk factors has been demonstrated. However, the current method for measuring FER(HDL) requires fresh serum samples and radioactive labeling of the samples, making it impractical for use in clinical laboratories. In this study, we developed a simple and precise HPLC method for the measurement of FER(HDL).

NADPH oxidase 2 plays a critical role in dysfunction and apoptosis of pancreatic β-cells induced by very low-density lipoprotein.

In type 2 diabetes, pancreatic β-cells cannot secret enough insulin compensate for insulin resistance, which are often accompanied by abnormality in lipid metabolism such as hypertriglyceridemia. It is reported that oxidative stress is involved in pancreatic β-cell dysfunction. However, molecular mechanisms linking between excessive generations of reactive oxygen species (ROS) and β-cell dysfunction and apoptosis induced by high levels of very low-density lipoprotein (VLDL) are poorly understood.

NADPH oxidase 2-derived reactive oxygen species are involved in dysfunction and apoptosis of pancreatic β-cells induced by low density lipoprotein.

Background: Increased levels of plasma cholesterol are a common feature of patient of type 2 diabetes. However, the links between elevated levels of low-density lipoprotein (LDL) and dysfunction of β-cells are still unclear.

Methods: The apoE(-/-)mice were fed with a high-fat, cholesterol-rich diet for 8 weeks.

A novel and precise method for simultaneous measurement of serum HDL and LDL subfractions and lipoprotein (a) cholesterol by ultracentrifugation and high-performance liquid chromatography.

Background: We developed an ultracentrifugation and high-performance liquid chromatography (HPLC) method for simultaneous measurement of cholesterol in serum high density lipoprotein (HDL) and low density lipoprotein (LDL) subfractions and lipoprotein (a) [Lp(a)].

Methods: Serum aliquots of 0.05 ml were centrifuged at background densities of 1.

[Relationship between fractional esterification rate of high density lipoprotein cholesterol and coronary artery disease].

Objective: To assess the relationship between fractional esterification rate of high density lipoprotein cholesterol (FER(HDL)) and coronary artery disease.

Methods: A total of 131 hospitalized patients underwent coronary angiography due to chest pain were included in the study and patients were divided into CAD group (n = 76) and non CAD group (n = 55) according to coronary angiogram. Clinical and laboratory data including biochemical laboratory, FER(HDL) and lipid subclasses were analyzed.

Augmented NADPH oxidase activity and p22phox expression in monocytes underlie oxidative stress of patients with type 2 diabetes mellitus.

Background: This study was to test the hypothesis that enhanced oxidative stress is induced in monocytes with over-activated NADPH oxidase during the development of type 2 diabetes mellitus.

Methods: Levels of glucose and lipids were analyzed in 73 diabetic patients and 36 controls. Superoxide dismutase (SOD), malondialdehyde (MDA), reactive oxygen species (ROS) and protein carbonylation were tested.

Serum LDL- and HDL-cholesterol determined by ultracentrifugation and HPLC.

Simple and precise methods for LDL-cholesterol (LDL-C) and HDL-cholesterol (HDL-C) measurements are essential for assessment of cardiovascular disease (CVD) risks and for lipid and lipoprotein studies. We report here an ultracentrifugation (UC) and HPLC method that requires substantially less specimen volume and provides the necessary reliability and throughput required by large-volume, high-quality research and clinical studies. 2-Mercaptoethanol (ME) was used to dissociate serum lipoprotein [a] (Lp[a]) into apolipoprotein [a] and Lp[a] remnant (Lp[a-]) and eliminated the contamination of Lp[a] in HDL separated by UC.

Jones oxidation and high performance liquid chromatographic analysis of cholesterol in biological samples.

A simple pre-column derivatization procedure for HPLC analysis of cholesterol in biological samples was developed. Cholesterol was treated with chromic acid and sulfuric acid in acetone (the Jones oxidation) and cholest-4-en-3,6-dione was formed. The reaction was finished in 5 min at room temperature and the product showed a strong UV absorbance at 250 nm that enabled an HPLC detection limit of 0.

Measurement of serum total glycerides and free glycerol by high-performance liquid chromatography.

Serum levels of total glycerides and free glycerol are important indices of lipid metabolism and cardiovascular disease risk. Convenient enzymatic methods of measurement have been available, but they are susceptible to interference. Situations exist in both research and clinical laboratories in which more specific and precise methods are needed.