nitrate-nitrite-nitric oxide pathway: findings from 20 years of the Tehran lipid and glucose study

Context: we describe here the contributions of the Tehran lipid and glucose study [TLGS] to understanding different aspects of the nitrate [NO3]-nitrite [NO2]-nitric oxide [NO] pathway in health and disease

Evidence Acquisition: all English-language documents from the TLGS, focused on NO pathway were searched using the PubMed, Scopus, and Embase databases

Results: reference values of serum concentrations of NO metabolites [nitrate + nitrite or NOx] were 11.5 - 76.4, 10.1 - 65.6, and 10.3 - 66.8_mol/L in men, women, and the total population, respectively. Circulating NOx was affected by age, smoking habits, menopause status, thyroid hormones, and various pathologic conditions. Elevated serum NOx was related to increased incidence of metabolic syndrome [odds ratio [OR] = 1.75, 95% confidence interval [CI] = 1.19 - 2.59], hypertriglyceridemic-waist phenotype [OR = 1.39, 95% CI = 1.05 - 1.93], chronic kidney disease [OR = 1.86, 95% CI = 1.10 - 3.14] in women, and cardiovascular disease [hazard ratio [HR] = 1.35, 95% CI = 1.01 - 1.80] in the total population. In participants with low vitamin C intake, higher intakes of NO2 [ >/= 8.77 mg/d] were accompanied with increased risk of diabetes [HR = 2.43, 95% CI = 1.45 - 4.05]. A decreased risk of hypertension [OR = 0.58, 95% CI = 0.33 - 0.98] and chronic kidney disease [OR = 0.50, 95% CI = 0.24 - 0.89] was observed in response to higher intakes of NO2

Conclusions: circulating NOx is associated with and could predict the risk of metabolic disorders in a general population. Moreover, dietary NO3/NO2 exposure from usual diets seems to contribute to development of noncommunicable diseases

Radioactive iodine therapy and glucose tolerance

Radioactive iodine therapy is commonly used as an adjuvant therapy in follicular and papillary thyroid carcinoma [PTC] and in the treatment of Graves' disease [GD]. The basis of this therapy is the accumulation of radioactive iodine by the sodium-iodide symporter [NIS] in the thyroid gland. Expression of NIS by extrathyroidal tissues such as islets of pancreas has been reported. Radioactive iodine uptake by pancreatic beta-cells can potentially damage these cells. In this study, we discuss the possible associations between radioactive iodine and glucose intolerance. Overall, radioactive iodine uptake by the pancreas may damage beta-cells and predispose patients to glucose intolerance or type 2 diabetes, particularly in patients exposed to radioactive iodine therapy following total thyroidectomy. Further studies are needed to clarify and confirm this association

The Effects of Ischemic Postconditioning on Myocardial Function and Nitric Oxide Metabolites Following Ischemia-Reperfusion in Hyperthyroid Rats

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.

Normality tests for statistical analysis: a guide for non-statisticians

Statistical errors are common in scientific literature and about 50% of the published articles have at least one error. The assumption of normality needs to be checked for many statistical procedures, namely parametric tests, because their validity depends on it. The aim of this commentary is to overview checking for normality in statistical analysis using SPSS

Is nitric oxide a hormone?

Nitric oxide [NO] is a simple ubiquitous signaling molecule and plays important roles in almost every biological system. Recent evidences suggest that NO may act as an endocrine molecule. The aim of this review is considering available literature on endocrine roles of NO and/or its metabolites, i.e. nitrite and nitrate. Existing data suggest the idea that NO is a hormone that after production in tissues, it is stabilized and transported as nitrite and/or Snitrosothiols in the blood to target cells

Prevalence of metabolic syndrome by the Adult Treatment Panel III, International Diabetes Federation, and World Health Organization definitions and their association with coronary heart disease in an elderly Iranian population

<p><b>INTRODUCTION</b>To determine the prevalence of the metabolic syndrome (MS) in an Iranian elderly population and show its association with coronary heart disease (CHD).</p><p><b>MATERIALS AND METHODS</b>This 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.</p><p><b>RESULTS</b>The 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.</p><p><b>CONCLUSIONS</b>In 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.</p>

[Triglyceride/HDL- cholesterol ratio [TG/HDL- C] beside the total cholesterol is a predictor for coronary heart disease in an Iranian men population]

Triglyceride/HDL-cholesterol ratio [TG/HDL-C] has been shown as an indicator for metabolic syndrome [MetS]. This study aimed to detect the role of this ratio to predict coronary heart disease [CHD] outcome in an Iranian men population with high prevalence of MetS. 1824 men >/= 40 years old, free of clinical cardiovascular disease at baseline, were included in the study from February 1999 to August 2001. Serum level of total cholesterol [TC], HDL-C, TG, and risk factors of CHD; including age, systolic blood pressure, diastolic blood pressure, body mass index, diabetes, smoking and family history of cardiovascular diseases were measured at initial phase of study. During a median follow up of 6.5 years until March 2007, a total of 163 new CHD events occurred. According to a Cox proportional hazard modeling, after adjustment for TC and other risk factors, men in the top quartile of TG/HDL-C relative to first quartile had a significant hazard ratio [HR] of 1.85 [95% Cl, 1.07-3.17]. Combined HR for TC and TG/HDL-C [men in the top quartiles of both TC and TG/HDL-C relative to first quartiles] after adjustment for other risk factors was 6.13 [95% Cl, 2.37-15.86]. The evaluation of both TG/HDL-C ratio and TC should be considered for CHD risk prediction in Iranian male population