Diagnostic value of lipids, bilirubin and LDH in patients with pleural effusion

The aim of this study was to evaluate the diagnostic value of the various parameters in differentiating pleural exudates from transudates and its possible role in the diagnosis of the most common causes of pleural effusion. Pleural effusion from 60 patients [36 males and 24 females with a mean age of 45 +/- 10 years] including 18 transudates [9 congestive heart failure, 6 hepatic cirrhosis and 3 with renal failure] and 42 exudates was analyzed. The study concluded that the level of cholesterol in the PF can be closely predicted from the S cholesterol level. A much lower fraction of cholesterol in the PF than in the S is associated with LDL, this suggested that the LDLs undergo metabolic alterations once they enter the pleural space. The PF triglyceride levels are not closely related to either S triglycerides levels. Pleural fluid lipids can not different malignant from tuberculous effusion. P/S bilirubin ratio is a good parameter for distinguishing exudates from transudates, but it has a less sensitivity and accuracy than Light's criteria

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