Melatonin reference limits at 3:00 AM and 8:00 AM in healthy adults.

We determined melatonin reference limits in blood serum of 129 healthy volunteers, aged 21 to 70 years, using enzyme-linked immunosorbent assay (IBL ELISA kit, Hamburg, Germany). At 3:00 AM, in almost full dark, the reference limits were found to be 18.3-134 pg/ml in males, 19.

Evaluation of the relationship between flow-mediated vasodilation and some atherogenic risk markers in severe hypercholesterolemia.

Background: In recent years, there has been a shift of interest in preventive cardiology towards primary prevention in high risk patients such as the patients with severe hypercholesterolemia. There is scanty information available in the respective literature on the levels of asymmetric dimethylarginine in severe hypercholesterolemia and on the correlation of flow-mediated vasodilation with some atherogenic risk biomarkers.

Aim: To assess the relationship of flow-mediated vasodilation with lipids, apoproteins and some serum markers of endothelial activation in severe hypercholesterolemia.

Asymmetric dimethylarginine--mechanisms and targets for therapeutic management.

Evidence has been accrued recently that chronic high levels of asymmetric dimethylarginine (ADMA) can be directly beneficial to the treatment of atherosclerotic vascular disorders thus making the substance a promising new therapeutic target. A therapeutic target can be theoretically each stage in the process of generation and elimination of asymmetric dimethylarginine. The methylation of L-arginine residues is a universal biological process involving hundreds of proteins but still with unknown effects.