Journal of School of Public Health and

Background and Aim: Type 2 diabetes mellitus is a heterogeneous disorder resulting from a combination of genetic and environmental factors which contribute to pathogenesis by influencing beta cell function and tissue insulin sensitivity. Protein tyrosine phosphatase 1B (PTP1B)" efficiently dephosphorylates the insulin receptor and attenuates insulin signaling. Recently, a 1484insG variant of the PTP1B gene was linked to increased risk of the metabolic syndrome in an Italian population, but this was not confirmed in subsequent studies. The purpose of this research was to investigate the association of 1484insG polymorphism of the PTP1B with obesity, insulin resistance, type 2 diabetes and other cardiovascular-related traits in an Iranian population.

Materials and Methods: The genotypes of 1484insG variant were determined by the PCR-RFLP method in 242 unrelated subjects, including 171 individuals with normal glucose tolerance and normal fasting glucose levels, and 71 type 2 diabetics. Insulin resistance was assessed using the homeostasis assessment model.

Results: The allelic frequency of the 1484insG polymorphism among type 2 diabetic patients and non-diabetic individuals was 6.3% and 3.8%, respectively (p=0.205). None of the subjects were homozygous for the 1484insG allele. Concerning quantitative traits in non-diabetic subjects, carriers of 1484insG allele had significantly higher body mass index (p=0.01), diastolic blood pressure (p=0.012), and HOMA-IR (p= 0.041) levels compared to those carrying the wild-type genotype. In type 2 diabetics, carriers of 1484insG allele had only significantly higher HOMA-B (P= 0/04) level compared to the individuals with the wild-type genotype.

Conclusion: Our results from a sample of Iranian type 2 diabetes cases and controls provide evidence that the 1484insG genotype of the PTP1B gene may be associated with obesity and insulin resistance.

Background and Aim: Organophosphate compoounds are cholinesterase activity inhibitors. Contact with them cause changes in the blood antioxidant enzyme levels and lipid peroxidation. The aim of this research was to investigate the simultaneous changes in cholinesterase, total serum antioxidant levels, and activities of some of the erythrocyte antioxidant enzymes and find possible correlations among these variables in pesticide factory workers.

Materials and Methods: This research was a cohort study carried out, during 2006, on the employees of a pesticide factory in Golestan Province, Iran. Blood samples were taken at the beginning (n=81 subjects) and after 3 months (n=63, of the initial 81). Erythrocyte glutathione peroxidase (GPx), superoxide dismutase (SOD) and total antioxidant levels were determined enzymatically (Randox, UK) and serum SOD was measured by the ELISA method (IBL, Germany). For the determination of malondialdehyde (MDA) a chemical method (based on thiobarbituric acid) was used. Confidence interval was 95% for all statistical tests.

Results: Levels of serum and erythrocyte SOD, serum MDA, and both serum and eryhthrocyte GPx significantly increased (paired t-test, p<0.05), while the serum total antioxidant level decreased (paired t-test, p<0.05). No statistically significnt correlation was seen between cholinesterase and changes in the other variables.

Conclusion: Contact with organophosphorus compounds will cause increases in lipid peroxidation and decreases in total antioxidants. It is suggested that, while more severe physical protective measures are taken, nutritional supplements be taken by the personnel to increase protection against hazardous materials.