Reduction in Nitric Oxide metabolites and antioxidants concentration in plasma after a single Cigarette smoking

In this study, the changes in the combined plasma concentrations of nitrate and nitrite as an index of nitric oxide [NO] concentration as well as the changes in the concentrations of major serum antioxidants [ascorbic acids and methionine] in smokers after smoking a single cigarette were measured. The effect of smoking a single cigarette was studied in 30 smokers and 15 nonsmokers [controls]. Plasma were collected before 5 and 60 minutes after smoking a single cigarette to measure the plasma levels of NO metabolites and antioxidants. Smoking a single cigarette significantly decreased NO metabolites concentrations by 10.2 +/- 1.1 mumol/L compared with the plasma concentrations at pre-smoking [13.5 +/- 1.2 mumol/L. The concentrations of ascorbic acid and methionine were also significantly lower after smoking a single cigarette [39.7 +/- 3.3 mumol/L and 8.1 +/- 0.7 mumol/L, respectively] compared with the plasma concentrations at pre-smoking [51.8 +/- 4.2 mumol/L and 10.2 +/- 0.7 mumol/L, respectively, for both]. These parameters returned to the pre-experimental levels at 60 minutes after smoking cessation. In nonsmokers, the same results were obtained, except that the impairments of NO and antioxidant release from the endothelium are less than in nonsmokers

Prognostic value of high plasma vitamin C concentration at birth associated with low antioxidant activity in preterm neonates

This study was done to measure vitamin C, ceruloplasmin and antioxidant activity of plasma at birth and their relation to gestational age. We also investigated whether the plasma antioxidant activity is influenced by the vitamin C to ceruloplamin ratio. We also investigated the relation between plasma antioxidant activity at birth and neonatal mortality. Blood samples were taken from 36 preterm newborns and 12 term newborns as a control group within two hours after birth. Plasma ascorbic acid, ceruloplasmin and antioxidant activity of plasma were measured. The premature infants were classified into 2 groups: Group I [survivors - 24] and group II [died, n = 12]. Compared to the full term newborns, the plasma antioxidant activity was significantly decreased [P<0.05] in preterm neo-nates, and showed a significant negative correlation with plasma ascorbic acid and vitamin C to ceruloplasmin ratio. The plasma antioxidant activity was significantly decreased in died preterm infants than survived preterm infants [P<0.05]. There was a significant high [P<0.05] plasma vitamin C in preterm neonates compared to full term neonates and also there was a significant high [P<0.05] vitamin C in died preterm neonates in comparison to survivors. There was a significant low [P<0.05] plasma ceruloplasmin in preterm neonates compared to full term neonates, but there was non significant difference in plasma ceruloplasmin between died and survived preterm neonates. Thus we concluded that plasma antioxidant activity at birth is a significant predictor of neonatal mortality. Some preterm neonates are born with low ceraloplasmin and high vitamin C concentration, the high vitamin C concentration may modulate theferroxidase activity of plasma cerulopasmin which may inhibit the antioxidant activity of plasma. This effect may be an important factor in the mortality of preterm neonates