Nitric oxide, antioxidant capacity, nitric oxide synthase and xanthine oxidase plasma levels in a cohort of burn patients

BACKGROUND: Nitric oxide (NO) is an important signal molecule in many types of cells and tissues. Efficiently balanced NO production was noted to play an important role in the healing of burns. However, the exact pathophysiological role of NO in burns and its potent relation with clinical and laboratory parameters has not been elucidated. METHODS: A cohort of 23 burn patients followed for 5 days were enrolled. NO, antioxidant capacity (AC), NO synthase (NOS) activity and xanthine oxidase (XO) activity were indirectly determined by fluorophotometer. Multiple regression against total burn surface area (TBSA), age, weight, height, proximity of septic episode, hemoglobin, white blood cells, percent of neutrophils, platelets, glucose, urea, potassium, sodium and albumin was performed. RESULTS: Elevation of NO, XO and AC levels is observed from day 2 (p<0.00001), day 4 (p=0.005) and day 6 (p=0.036), respectively. At the end of follow-up period (day 6), NO production was found to independently correlate with TBSA, glucose levels and percent of neutrophils (p=0.0004), AC with age, hemoglobin and glucose levels (p=0.012), and NOS with proximity of septic episode and glucose levels (p=0.027). CONCLUSIONS: NO production exerts its prophylactic effect from the first 24h after burn, and is independently correlated with severe injury, enhanced neutrophil motivation and augmented glucose levels, thus possibly representing a response to stress. This need might trigger induction of XO and salvage of antioxidants, as suggested by their rise at a later stage. These data underline that an effort to compromise stress and to administer antioxidants could be a priority in the treatment of these patients.     

Psychosocial predictors of sexual initiation and high-risk sexual behaviors in early adolescence

Background  

This longitudinal study examined psychosocial factors associated with risky sexual behavior in early adolescence.     

LC-MS/(MS) confirmatory doping control analysis of intact phase II metabolites of methenolone and mesterolone after Girard's Reagent T derivatization

In the present study, the application and evaluation of Girard's Reagent T (GRT) derivatization for the simultaneous detection and significantly important identification of different phase II methenolone and mesterolone metabolites by LC-MS/(MS) are presented. For the LC-MS analysis of target analytes two complementary isolation methods were developed; a derivatization and shoot method in which native urine is diluted with derivatization reagent and is injected directly to LC-MS and a liquid–liquid extraction method, using ethyl acetate at pH 4.5, for the effective isolation of both sulfate and glucuronide metabolites of the named steroids as well as of their free counterparts. For the evaluation of the proposed protocols, urine samples from methenolone and mesterolone excretion studies were analyzed against at least one sample from a different excretion study. Retention times, along with product ion ratios, were evaluated according to the WADA TD2021IDCR requirements, in order to determine maximum detection and identification time windows for each metabolite. Established identification windows obtained after LC-MS/(MS) analysis were further compared with those obtained after GC-MS/(MS) analysis of the same samples from the same excretion studies, for the most common analytes monitored by GC-MS/(MS). Full validation was performed for the developed derivatization and shoot method for the identification of methenolone metabolite, 3α-hydroxy-1-methylen-5α-androstan-17-one-3-glucuronide (mth3). Overall, the GRT derivatization presented herein offers a tool for the simultaneous sensitive detection of free, intact glucuronide and sulfate metabolites by LC-MS/(MS) that enhance significantly the detection and identification time windows of specific methenolone and mesterolone metabolites for doping control analysis.