ABSTRACT
Background: Nitrous oxide irreversibly oxidizes the cobalt atom of vitamin B12, inactivating it which is a co-factor for methionine synthase. Methionine is an essential aminoacid that serves as a methyl donor (via its activated from s-adenosyl methionine) in hundreds of biological reactions. Aim: The aim of the study was to evaluate Methionine Synthase (MTR) gene polymorphism in persons who are exposed to trace quantities of anaesthetic gases in operation theatres. Materials and methods: 87 cases of physical status American society of anaesthesiologists (ASA) I and II exposed to anaesthetic gases in operation theaters at Gandhi Hospital and Osmania General Hospital, Hyderabad were selected for study. Also 150 controls who were not exposed to anesthetic gases were selected at random to compare with the data generated on the subjects exposed to these gases. Results: This study entitled study of methionine “synthase (MTR) gene polymorphisms in personnel exposed to trace quantities of anaesthetic gases in operation theatres” was conducted on 87 exposed and 150 non exposed subjects. The objective was to evaluate the effect of Nitrous Oxide on Methionine Synthase (MTR) gene polymorphisms. No statistically significant difference was observed in the distribution of genotypes between the two groups. Conclusion: The result of the study suggest that large studies would be required to provide statistical power and recommends that examination should be done on large populations to assure at better conclusions.
ABSTRACT
PURPOSE: Methionine synthase (MTR) and 5,10-methylenetetrahydrofolate reductase (MTHFR) are the main regulatory enzymes for homocysteine metabolism. The present case- control study was conducted to determine whether there is an association between the MTR 2756A > G or MTHFR 677C > T polymorphism and plasma homocysteine concentration in Korean subjects with ischemic stroke. MATERIALS AND METHODS: DNA samples of 237 patients who had an ischemic stroke and 223 age and sex-matched controls were studied. MTR 2756A > G and MTHFR 677C > T genotypes were determined by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). RESULTS: Frequencies of mutant alleles for MTR and MTHFR polymorphisms were not significantly different between the controls and cases. The patient group, however, had significantly higher homocysteine concentrations of the MTR 2756AA and MTHFR 677TT genotypes than the control group (p=0.04 for MTR, p=0.01 for MTHFR). The combined MTR 2756AA and MTHFR 677TT genotype (p= 0.04) and the homocysteine concentrations of the patient group were also higher than those of the controls. In addition, the genotype distribution was significant in the MTHFR 677TT genotype (p=0.008) and combined MTR 2756AA and MTHFR 677TT genotype (p=0.03), which divided the groups into the top 20% and bottom 20% based on their homocysteine levels. CONCLUSION: The results of the present study demonstrate that the MTR 2756A > G and MTHFR 677C > T polymorphisms interact with elevated total homocysteine (tHcy) levels, leading to an increased risk of ischemic stroke.