The association between serum total testosterone and progression of hyperglycemia: a 15-year prospective cohort study.

BACKGROUND: The association between low testosterone concentration and increased risk of hyperglycemia in men has been demonstrated in observational and interventional studies. However, considering a variety of confounding factors, limited population-based studies have so far been conducted. Also, no information is available regarding the effect of testosterone on progressive development of dysglycemia. OBJECTIVE: To examine the effect of total testosterone on development of pre-diabetes/diabetes in normoglycemic middle-aged and older men. MATERIALS AND METHODS: Data were obtained from the Tehran Lipid and Glucose Study, a community-based prospective cohort of an Iranian population. Analyses were conducted on 903 normoglycemic eligible men aged 30-70 years. An illness-death model was applied to estimate the probabilities of three transitional phases of normoglycemia→diabetes, normoglycemia→pre-diabetes, and pre-diabetes→diabetes. RESULTS: Over a median follow-up of 12 years, 0.9% individuals developed diabetes. Per unit increase (ng/mL) in testosterone concentration, the transition rate from normoglycemia to pre-diabetes decreased by 6% [hazard ratios (HRs): 0.94 (95% confidence interval (CI): 0.90, 0.99)]. However, no effect for testosterone on the progression of diabetes from normoglycemia or pre-diabetes was observed [HRs: 0.79 (95% CI: 0.44, 1.41) and 0.98 (95% CI: 0.84, 1.16), respectively]. High body mass index was a strong predictor of hyperglycemia within all transitions. DISCUSSION: Independent of major confounding factors, low testosterone was associated with normoglycemia progression to pre-diabetes, but not with pre-diabetes to diabetes, which might indirectly highlight the stronger impact of other risk factors after occurrence of pre-diabetes. CONCLUSION: Low testosterone concentrations in men are associated with progression from normoglycemia to pre-diabetes, but not from pre-diabetes to diabetes.

In-vitro Study of Photothermal Anticancer Activity of Carboxylated Multiwalled Carbon Nanotubes.

BACKGROUND AND OBJECTIVE: Multi-walled Carbon Nano Tubes (MWCNTs) as an important element of nanosciences have a remarkable absorption in the region of NIR window (650-900 nm) which can overcome the limitations of deep treatment in photothermal therapy. To disperse MWCNTs in water, it is proposed to attach carboxylated functional group (-COOH) to MWCNTs in order to increase dispersivity in water. MATERIALS AND METHODS: A stable suspension of MWCNTs-COOH with different concentrations (from 2.5 to 500 µg/ml) was prepared. Then, they were compared for their ability to increase temperature in the presence of 810 nm laser irradiation and through a wide range of radiation time (from 20 to 600 s) and three laser powers (1.5, 2 and 2.5 w). The temperature rise was recorded real time every 20 seconds by a precise thermometer. RESULTS: Absorption spectrum of MWCNTs-COOH suspension was remarkably higher than water in a wavelength range of 200 to 1100 nm. For example, using the concentrations of 2.5 and 80 µg/ml of MWCNTs-COOH suspension caused a temperature elevation 2.35 and 9.23 times compared to water, respectively, upon 10 min laser irradiation and 2.5 w. Moreover, this predominance can be observed for 1.5 and 2 w radiation powers, too. Our findings show that the maximum of temperature increase was obtained at 80 µg/ml concentration of MWCNT-COOH suspension for three powers and through all periods of exposure time. Our results show that the minimum required parameters for a 5°C temperature increase (a 5°C temperature increase causes cell death) were achieved through 2.5 w, 28 µg/ml concentration and 20 second irradiation time in which both concentration and radiation times were relatively low. CONCLUSION: Our results showed that MWCNTs-COOH can be considered as a potent photothermal agent in targeted therapies. New strategies must be developed to minimize the concentration, irradiation time and radiation power used in experiments.