Elevated plasma levels of the sulfur-containing amino acid homocysteine increase the risk for atherosclerosis, stroke, and possibly Alzheimer's disease, but the underlying mechanisms are unknown. We now report that homocysteine induces apoptosis in rat hippocampal neurons. DNA strand breaks and associated activation of poly-ADP-ribose polymerase (PARP) and NAD depletion occur rapidly after expo...

Catalase, an antioxidant enzyme responsible for degradation of hydrogen peroxide, is protective in many diseases. The amino-acid homocysteine has been suggested to be a pro-oxidant with elevated levels linked to the oxidative stress seen in Alzheimer’s and other diseases. This study shows that homocysteine inhibits the breakdown of hydrogen peroxide by catalase. Physiological concentrations of ...

Purpose: Infertility is described as unexplained when all of the tests a basic infertility evaluation return within normal limits and present in 15% infertile couples. Some studies indicate that there an association between methylenetetrahydrofolate reductase (MTHFR C677T A1298C) mutations male or female grown adults. The objective this study was to analyze distributions MTHFR’s A1298C genotype...

Recent evidence suggests that an increased plasma concentration of the sulphur amino acid homocysteine is a risk factor for the development of vascular disease. The tissue(s) responsible for homocysteine production and export to the plasma are not well known. However, given the central role of the liver in amino acid metabolism, we developed a rat primary hepatocyte model in which homocysteine ...

Despite the growing evidence that plasma homocysteine is a cardiovascular risk factor, the mechanism behind the vascular injuries is still unknown. Studies are difficult as a result of the fact that little is known about the formation of different homocysteine species in vivo. Since extracellular glutathione and cysteine may influence the formation of different homocysteine species, we have in ...

BACKGROUND Elevated plasma homocysteine levels are a risk factor for coronary heart disease, but the prognostic value of homocysteine levels in patients with established coronary artery disease has not been defined. METHODS We prospectively investigated the relation between plasma total homocysteine levels and mortality among 587 patients with angiographically confirmed coronary artery diseas...

Homocysteine is an amino acid, which plays several important roles in human physiology. A wide range of disorders, including neuropsychiatric disorders and autism, are associated with increased homocysteine levels in biological fluids. Various B vitamins: B6 (pyridoxine), B12 (cobalamin), and B9 (folic acid) are required as co-factors by the enzymes involved in homocysteine metabolism. Therefor...

INTRODUCTION Raynaud's phenomenon (RP) is a paroxysmal and recurrent acral ischemia resulting from an abnormal arterial vasospastic response to cold or emotional stress. Homocysteine, a sulphured amino acid, has been linked to cardiovascular and neurodegenerative diseases, diabetes, thrombosis, and bone fragility. Homocysteine has been also linked to the pathogenesis of RP, as increased serum h...

OBJECTIVE Homocysteine is a sex-related risk factor for cardiovascular disease but the reason for dimorphism is unclear. It has been hypothesized that fat-free mass is an independent determinant of the circulating homocysteine and methionine concentrations. METHODS The relationship of homocysteine to body composition was investigated in 52 healthy middle-aged 40-60 year olds. Plasma total hom...

Editing of the non-protein amino acid homocysteine, a frequent type of error-correcting process in amino acid selection for protein synthesis by an aminoacyl-tRNA synthetase, results in formation of a cyclic thioester, homocysteine thiolactone. Here it is shown that human cells in which homocysteine metabolism is deregulated by a mutation in the cystathionine beta-synthase gene and/or by an ant...