The Biological Variability of Plasma Ceramides in Healthy Subjects.

Background: Ceramides are bioactive lipid species that mediate numerous cell-signaling events. Elevated plasma ceramides concentration constitutes a risk factor for several pathologies. Multiple studies have affirmed the plasma concentrations of 4 specific ceramides (Cer16:0, Cer18:0, Cer24:0, and Cer24:1) can predict cardiovascular disease risk.

Biological variability of lipoprotein-associated phospholipase A activity in healthy individuals.

Objectives: Measuring lipoprotein-associated phospholipase A (Lp-PLA) activity can aid in identifying individuals at higher risk of coronary heart disease. However, the biological variation of Lp-PLA activity and corresponding reference change value (RCV) is unknown which limits interpretation of results. In this study we aim to define the intra- and inter-individual variability of Lp-PLA activity in a healthy reference population.

Response of novel biomarkers to BNP infusion in patients with decompensated heart failure: a multimarker paradigm.

Multibiomarker paradigms have been proposed to diagnose, define progression, and to monitor therapy of heart failure (HF) patients. The aim of this study was to evaluate the prognostic and therapy-monitoring potential of four novel biomarkers (copeptin, midregional proatrial natriuretic peptide (MR-proANP), neopterin, and procalcitonin) which have been shown to be elevated in the plasma of patients with HF and reported to have prognostic value. In a prospective study of 40 patients hospitalized for decompensated HF and who received nesiritide infusions as part of their care, blood was drawn before, during, and postinfusion and assayed for the novel biomarkers.

Effects on lipoprotein particles of long-term dehydroepiandrosterone in elderly men and women and testosterone in elderly men.

Context: Although age-related declines in dehydroepiandrosterone sulfate (DHEAS) and testosterone are associated with cardiovascular risk, it remains to be determined whether replacement of these hormones improves cardiovascular risk factors.

Objective: This study sought to determine the effect of long-term replacement of dehydroepiandrosterone (DHEA) in elderly men and women and testosterone in elderly men on lipid and lipoprotein concentrations and particle sizes.

Methods: A 2-yr randomized, placebo-controlled, double-blind study was conducted in 87 elderly men with low levels of DHEAS and bioavailable testosterone and 57 elderly women with low levels of DHEAS.

Coronary artery endothelial dysfunction is positively correlated with low density lipoprotein and inversely correlated with high density lipoprotein subclass particles measured by nuclear magnetic resonance spectroscopy.

Objective: The association between cholesterol and endothelial dysfunction remains controversial. We tested the hypothesis that lipoprotein subclasses are associated with coronary endothelial dysfunction.

Methods And Results: Coronary endothelial function was assessed in 490 patients between November 1993 and February 2007.

Effect of dehydroepiandrosterone replacement on lipoprotein profile in hypoadrenal women.

Context: Levels of dehydroepiandrosterone (DHEA) and its sulfate form (DHEAS) are inversely associated with cardiovascular mortality in men but not women. Very little evidence is available on the impact of DHEA administration on lipoprotein profile in women. DHEAS levels are very low/undetectable in hypoadrenal women.

Aspirin responsiveness in healthy volunteers measured with multiple assay platforms.

Background: We evaluated the sensitivity, precision, and concordance of 4 assays designed to detect aspirin responsiveness or resistance.

Methods: Twenty-nine healthy laboratory volunteers took 80 mg aspirin for 7 days, and a subset of volunteers took 325 mg aspirin for an additional 7 days. We measured platelet function by light transmission aggregometry with arachidonic acid, PFA-100, and VerifyNow.

Lipoprotein-associated phospholipase A2 is an independent marker for coronary endothelial dysfunction in humans.

Objective: The purpose of the current study was to determine whether lipoprotein-associated phospholipase A2 (Lp-PLA2) is associated with coronary endothelial dysfunction and is a predictor of endothelial dysfunction in humans.

Methods And Results: Patients (172) with no significant coronary artery disease (<30% stenosis) undergoing assessment of coronary endothelial function were studied. Endothelial function was assessed by the change in coronary blood flow and coronary artery diameter in response to intracoronary acetylcholine.

Automated spectrophotometric analysis of mitochondrial respiratory chain complex enzyme activities in cultured skin fibroblasts.

Background: Mitochondrial respiratory chain complex (RCC) disorders may occur as commonly as 1 in 8500 individuals. Because of the great variability of phenotypic presentations, measurement of individual RCC enzyme activities is a crucial diagnostic process. Current assay methods are time-consuming and labor-intensive and thus constitute a major impediment to clinical practice.

Electrophoretic measurement of lipoprotein(a) cholesterol in plasma with and without ultracentrifugation: comparison with an immunoturbidimetric lipoprotein(a) method.

Objectives: Elevated plasma lipoprotein(a) [Lp(a)] is a significant risk factor for vascular disease. Standardization of Lp(a) mass measurement is complicated by the heterogeneity of apolipoprotein(a) [apo(a)]. We investigated whether Lp(a) cholesterol measurement, which is not influenced by apo(a) size, is a viable alternative to measuring Lp(a) mass.