Oxidative stress in smokers, asthma and COPD

An imbalance between oxidants and antioxidants is proposed in smokers, and in patients with airways diseases. We tested this hypothesis by measuring the plasma levels of oxidants [MDA, N. O]* and antioxidants [SOD* and Catalase] in three different groups. Healthy control group [30], divided to healthy smokers [15] and healthy non smokers [15]. Asthmatic group [30] divided to chronic persistent [15] and acute asthma [15 cases]. COPD* group divided to stable COPD [15 cases] and acute exacerbation of COPD [15 cases]. The plasma oxidants was markedly increased with reduced levels of antioxidant, in healthy smokers, as compared with healthy non smokers, [p < 0.001], Plasma oxidants was also increased in patients presenting with asthma, and COPD [p <0.001 and <0.05], and even higher in those with acute exacerbation of these conditions, with reduced the plasma antioxidant products. There was a negative correlation between oxidants and antioxidants with respect on MDA and SOD in asthmatic and COPD patients, [r = -0.16. p<0.001 and r=- 0, 72, p <0.05 respectively]. There was no significant correlation between plasma antioxidant and age, [r = 0.35, p >0.05]. Our data also demonstrate a positive correlation between Pa02 and plasma antioxidant [SOD] in patients with acute exacerbation of COPD. In summary, our results provide new evidence for profound oxidant -antioxidants imbalance in smokers, patients of COPD and asthma, associated with evidence of increased oxidative stress. The relationship between the decrease in antioxidant products in plasma and the pathogenesis of acute exacerbation of these conditions may result from different mechanisms and require further study. *MDA = malondialdehyde-*N. O = nitric oxide-*COPD - chronic obstructive pulmonary disease-*SOD = sodium oxide dismutase

Comparative study of rocuronium and vecuronium on the neuromuscular activity in experimental animals

Rocuronium is one of the newest non depolarizing neuromuscular blocking drugs. In this study, the effects of rocuronium and vecuronium as neuromuscular blocking agents on isolated rat phrenic nerve diaphragm and intact gastrocnemius sciatic nerve preparation in the cat were compared. The effect of gradually increasing doses of rocuronium [3-48 mu g /ml] and vecuronium [0.58 mu g/ ml] on the amplitude of contraction of isolated muscle in response to indirect electrical stimulation was recorded. Also, the effect of rocuronium [0.06-0.12 mg / Kg] and vecuronium [0.01-0.02 mg / kg] on the electrically induced gastrocnemius sciatic nerve was studied. Both drugs produced significant dose dependent reductions in the amplitude of rat phrenic nerve diaphragmatic contractions, but the effect of vecuronium was more than rocuronium. On cats gastrocnemius sciatic nerve preparations, the pattern of neuromuscular blockade [magnitude on set to maximum blockade and duration of block] of both drugs was also dose dependent. The results of this study demonstrated that rocuronium had significantly shorter time of onset, less potent with shorter duration of motor block than vecuronium