Identification and quantitation of electron-transport components in human polymorphonuclear neutrophils

Using dithionite difference spectra we have detected cytochrome b in highly purified human neutrophils at a concentration of 0.08 nmol/mg protein. The presence of quinone was identified in lipid extracts at a concentration of approx. 0.06 nmol/mg protein. It was identified as ubiquinone-10 by mass spectrographic analysis. Simultaneous measurements of cytochrome oxidase indicated that these compounds could not be attributed to mitochondrial contamination. These results are compatible with the hypothesis that initiation of the respiratory burst in human neutrophils involves a multicomponent electron-transport system.     

The role of Pseudomonas aeruginosa elastase as a potent inflammatory factor in a rat air pouch inflammation model

Pseudomonas aeruginosa, an opportunistic pathogen, can cause life threatening infections in patients compromised by underlying respiratory disease like bronchiectasis, cystic fibrosis and diffuse panbronchiolitis. Most strains of P. aeruginosa produce some kind of protease with broad substrate specificities during the infectious state in the host. P. aeruginosa elastase, one of the strongest exotoxins, has a tissue-damaging proteolytic activity and is capable of degrading such plasma proteins as immunoglobulins, complement factor and cytokines. The present study focused on the effect of P. aeruginosa elastase and was designed to evaluate the neutrophil accumulation at the inflammation site mediated by P. aeruginosa elastase in the inflammatory response in the host. An air pouch model in rats, considered as a useful model of inflammation, was used to analyze the number of leukocytes, the volume of exudate and the concentration of interleukin-8 after the injection of P. aeruginosa elastase into the pouch cavity. The number of neutrophils and the volume of exudate in the pouch cavity increased significantly at 4 h, peaked at 8 h in a dose-dependent manner and then decreased at 24 h. The concentration of interleukin-8 in pouch fluid peaked 4 h earlier than the peak of the neutrophil number. The enzymatic activity of P. aeruginosa elastase seemed to reinforce the inflammation process. The influence of lipopolysaccharide contamination was negligible. Although these observations were made in the subcutaneous cavity, they indicate that P. aeruginosa elastase plays a role as an immunoprovocative factor in the inflammatory response in cases of infection with P. aeruginosa.