Plasma total homocysteine concentrations in a Turkish population sample.

OBJECTIVES: The purpose of this study is to determine the reference of plasma total homocysteine levels from a Turkish population and to investigate the relationship of plasma total homocysteine levels with sex and age groups. DESIGN AND METHODS: Plasma total homocysteine levels were measured in 2257 Turkish individuals (1381 men and 876 women) aged 1-90 years. Plasma total homocysteine concentrations were determined using high performance liquid chromatography with fluorescence detector. RESULTS: The mean plasma total homocysteine level was significantly higher in men (mean, 10.6 micromol/L) than in women (mean, 8.7 micromol/L), P < 0.001. The mean plasma total homocysteine levels for the 1-10, 11-20, 21-30, and 31-40, 41-50, 51-60, and 61-70, 71-80, 81-90 age groups, were 6.5, 9.6, 10.1, and 10.4, 10.5, 10.9, and 11.3, 12.7, 14.6 miromol/L in men and 7.1, 7.6, 7.5, and 7.8, 8.7, 9.4, and 10.3, 11.2, 13.3 micromol/L in women, respectively. CONCLUSIONS: These data indicate the significance of sex- and age-associated differences of plasma total homocysteine levels in Turkish subjects. Plasma total homocysteine levels were increasing with age and men were found to have higher levels than women, as is found in other populations.

The use of melatonin to combat mustard toxicity. REVIEW.

Among the most readily available chemical warfare agents, sulfur mustard (SM) has been the most widely used chemical weapon. The toxicity of SM as an incapacitating agent is of much greater importance than its ability to cause lethality. Oxidative stress is the first and key event in the pathogenesis of SM toxicity. The involvement of inducible nitric oxide (iNOS) in SM toxicity, however, also leads to elevated nitrosative stress; thus, the damage caused by SM is nitro-oxidative stress because of peroxynitrite (ONOO-) production. Once ONOO- is formed, it activates nuclear factor-kappaB (NF-kappaB) and activator protein-1 (AP-1) leading to pro-inflammatory gene expression thereby promoting inflammation; additionally, ONOO- directly exerts harmful effects by damaging all biomolecules including lipids, proteins and DNA within cells. DNA damage is sensed by an important DNA repair enzyme, poly (ADP-ribose) polymerase (PARP); this enzyme repairs molecular damage by using nicotinamide adenine dinucleotide (NAD+) as a substrate. Over-activation of PARP, due to severe DNA damage, consumes vast amounts of the respiratory coenzyme NAD+ leading to a cellular energy crisis. This pathophysiologic mechanism eventually results in cellular dysfunction, apoptosis or necrosis. Therefore, classic antioxidants may have limited beneficial effects on SM toxicity. Melatonin is a multifunctional indolamine which counteracts virtually all pathophysiologic steps and displays significant beneficial effects against ONOO--induced cellular toxicity. Melatonin has the capability of scavenging both oxygen and nitrogen-based reactants including ONOO- and blocking transcriptional factors which induce pro-inflammatory cytokines. The delayed toxicity of SM, however, currently has no mechanistic explanation. We propose that epigenetic aberrations may be responsible for delayed detrimental effects of mustard poisoning. Therefore, as a putative epigenetic modulator, melatonin may also be beneficial to subjects with delayed toxicity of SM.