Ischemic postconditioning (IPost) could decrease ischemia-reperfusion (IR) injury. It has not yet reported whether IPost is useful when ischemic heart disease is accompanied with co-morbidities like hyperthyroidism. The aim of this study was to examine the effect of IPost on myocardial IR injury in hyperthyroid male rats. Hyperthyroidism was induced with administration of thyroxine in drinking water (12 mg/L) over a period of 21 days. After thoracotomy, the hearts of control and hyperthyroid rats were perfused in the Langendorff apparatus and subjected to 30 minutes global ischemia, followed by 120 minutes reperfusion; IPost, intermittent early reperfusion, was induced instantly following ischemia. In control rats, IPost significantly improved the left ventricular developed pressure (LVDP) and +/-dp/dt during reperfusion (p<0.05); however it had no effect in hyperthyroid rats. In addition, hyperthyroidism significantly increased basal NOx (nitrate+nitrite) content in serum (125.5+/-5.4 micromol/L vs. 102.8+/-3.7 micromol/L; p< 0.05) and heart (34.9+/-4.1 micromol/L vs. 19.9+/-1.94 micromol/L; p<0.05). In hyperthyroid groups, heart NOx concentration significantly increased after IR and IPost, whereas in the control groups, heart NOx were significantly higher after IR and lower after IPost (p< 0.05). IPost reduced infarct size (p<0.05) only in control groups. In hyperthyroid group subjected to IPost, aminoguanidine, an inducible nitric oxide (NO) inhibitor, significantly reduced both the infarct size and heart NOx concentrations. In conclusion, unlike normal rats, IPost cycles following reperfusion does not provide cardioprotection against IR injury in hyperthyroid rats; an effect that may be due to NO overproduction because it is restored by iNOS inhibition.
Animals ; Drinking Water ; Heart ; Humans ; Hyperthyroidism ; Ischemia ; Ischemic Postconditioning* ; Male ; Myocardial Ischemia ; Nitric Oxide* ; Rats* ; Reperfusion ; Thoracotomy ; Thyroxine

Background: Styrene is one of the aromatic compounds used in acetonitrile–butadiene–styrene (ABS) producing petrochemicals, which has an impact on health of workers. Therefore, this study aimed to investigate the health risks of styrene emitted from the petrochemical industry in Iran. Methods: Air samples were collected based on NIOSH 1501 method. The samples were analyzed by the Varian-cp3800 gas chromatograph. Finally, risk levels of styrene's health effects on employees were assessed by the quantitative method of the U.S. Environmental Protection Agency (U.S. EPA) and the semiquantitative way by the Singapore Occupational Safety and Health Association. Results: Based on the results, the employees had the highest average exposure to styrene vapors (4.06x10-1 mg.(kg - day)-1) in the polybutadiene latex (PBL) unit. Therefore, the most top predictors of cancer and non-cancer risk were 2.3x10-4 and 7.26x10-1, respectively. Given that the lowest average exposure (1.5x10-2mg.(kg - day)-1) was in the dryer unit, the prediction showed a moderate risk of cancer (0.8x10-6) and non-cancer (2.3x10-3) for the employees. The EPA method also predicted that there would be a definite cancer risk in 16% and a probable risk in 76% of exposures. However, according to the semiquantitative approach, the rate of risk was at the “low” level for all staff. The results showed that there was a significant difference (p < 0.05) between the units in exposure and health risk of styrene (p < 0.05). Conclusion Given the high risk of styrene's health effects, appropriate control measures are required to reduce the exposure level.

Background: Styrene is one of the aromatic compounds used in acetonitrile–butadiene–styrene (ABS) producing petrochemicals, which has an impact on health of workers. Therefore, this study aimed to investigate the health risks of styrene emitted from the petrochemical industry in Iran. Methods: Air samples were collected based on NIOSH 1501 method. The samples were analyzed by the Varian-cp3800 gas chromatograph. Finally, risk levels of styrene's health effects on employees were assessed by the quantitative method of the U.S. Environmental Protection Agency (U.S. EPA) and the semiquantitative way by the Singapore Occupational Safety and Health Association. Results: Based on the results, the employees had the highest average exposure to styrene vapors (4.06x10-1 mg.(kg - day)-1) in the polybutadiene latex (PBL) unit. Therefore, the most top predictors of cancer and non-cancer risk were 2.3x10-4 and 7.26x10-1, respectively. Given that the lowest average exposure (1.5x10-2mg.(kg - day)-1) was in the dryer unit, the prediction showed a moderate risk of cancer (0.8x10-6) and non-cancer (2.3x10-3) for the employees. The EPA method also predicted that there would be a definite cancer risk in 16% and a probable risk in 76% of exposures. However, according to the semiquantitative approach, the rate of risk was at the “low” level for all staff. The results showed that there was a significant difference (p < 0.05) between the units in exposure and health risk of styrene (p < 0.05). Conclusion Given the high risk of styrene's health effects, appropriate control measures are required to reduce the exposure level.

INTRODUCTIONTo determine the prevalence of the metabolic syndrome (MS) in an Iranian elderly population and show its association with coronary heart disease (CHD).

MATERIALS AND METHODSThis is a cross-sectional study on 720 Iranian men and women aged > or = 65 years who participated in the Tehran Lipid and Glucose Study (TLGS). Logistic regression analysis was used to estimate the odds ratio (OR) of developing CHD in model 1, an age-adjusted model; model 2, adjusted for age, smoking status, premature history of CHD and low-density lipoprotein (LDL) cholesterol; and model 3, adjusted for mentioned variables plus the MS components.

RESULTSThe prevalence of MS was 50.8%, 41.8% and 41.9% based on the Adult Treatment Panel (ATPIII), the World Health Organisation (WHO), and the International Diabetes Federation (IDF) definitions, respectively. The IDF definition showed high agreement with the ATPIII definition. Age-adjusted OR (95% CI) of the MS for CHD was 1.6 (1.2 to 2.2) by both the ATPIII and WHO definitions and 1.4 (1.0 to 1.9) by the IDF definition. IDF-defined MS lost its association with CHD in model 2. In model 3, obesity (WHO definition) and high blood pressure (ATPIII and WHO definitions) were associated with CHD.

CONCLUSIONSIn an elderly Iranian population MS is highly prevalent. ATPIII and WHO definitions seem to be more pertinent than IDF for screening CHD risk. None of these definitions showed association with CHD when considering their components.

Age Factors ; Aged ; Coronary Disease ; blood ; epidemiology ; etiology ; Cross-Sectional Studies ; Female ; Humans ; Insulin Resistance ; Iran ; epidemiology ; Male ; Mass Screening ; methods ; Metabolic Syndrome ; classification ; complications ; epidemiology ; Middle Aged ; Prevalence ; Prospective Studies ; Risk Assessment ; methods ; Risk Factors ; Surveys and Questionnaires ; Urban Population ; World Health Organization