Paraoxonasel phenotype distribution in Thais.

OBJECTIVE: To determine the PON1 activity and phenotype distribution in a Thai population. STUDY DESIGN: Prospective Descriptive study. MATERIAL AND METHOD: Between October 2001 and April 2002, 160 healthy Thai individuals aged 20-74 years were assessed for PON1 activity and the phenotype distribution by using dual substrate method. RESULTS: The means +/- SD of basal, salt-stimulated paraoxonase and arylesterase activities were 239.7 +/- 83.9 nmol/min/mL 555.2 +/- 222.2 nmol/min/mL and 147.6 +/- 33.8 micromol/min/mL respectively. The authors observed a wide interindividual variability up to 6.9-fold for paraoxonase activity and 4.6-fold for arylesterase activity. The authors found a range of ssPON/ARE ratio from 1.04 to 7.05 and three distinctive phenotype modals of AA (1.04-2.25), AB (2.44-4.29), and BB (4.53-7.05) with frequencies of 14.4% (AA), 51.9% (AB), and 33.7% (BB). The authors also observed the association of sex with lipid parameters and PON1 activity. CONCLUSION: The distribution of PON1 phenotype in Thais is clearly trimodal with high frequency in BB phenotype.

Genetic variations of glutathione s-transferase influence on blood cadmium concentration.

The glutathione S-transferases (GSTs) are involved in biotransformation and detoxification of cadmium (Cd). Genetic polymorphisms in these genes may lead to interindividual variation in Cd susceptibility. The objective of this study was to assess the association of GSTs (GSTT1, GSTM1, and GSTP1 Val105Ile) polymorphisms with blood Cd concentrations in a nonoccupationally exposed population. The 370 blood samples were analyzed for Cd concentration and polymorphisms in GSTs genes. Geometric mean of blood Cd among this population was 0.46 ± 0.02 µg/L (with 95% CI; 0.43-0.49 µg/L). Blood Cd concentrations in subjects carrying GSTP1 Val/Val genotype were significantly higher than those with Ile/Ile and Ile/Val genotypes. No significant differences in blood Cd concentrations among individual with gene deletions of GSTT1 and GSTM1 were observed. GSTP1/GSTT1 and GSTP1/GSTM1 combinations showed significantly associated with increase in blood Cd levels. This study indicated that polymorphisms of GSTP1 combined with GSTT1 and/or GSTM1 deletion are likely to influence on individual susceptibility to cadmium toxicity.