Oxidative metabolism of leukocytes and its relationship to bactericidal activity

Hypochlorite-modified adenine nucleotides: structure, spin-trapping, and formation by activated guinea pig polymorphonuclear leukocytes

Adenosine and its nucleotides react with hypochlorite to form unstable products that have been identified as the N6 chloramine derivatives. These chloramines spontaneously oligomerize, form stable adducts with proteins and nucleic acids, and are converted with loss of chlorine to the original nucleoside or nucleotide by reducing agents. The chloramines are associated with a free radical, and the spin-trapping of adenosine chloramine with 5,5-dimethyl-1-pyrroline-N-oxide (DMPO) yielded a mixture of unstable nitroxyl adducts that corresponded to nitrogen-centered radicals from the parent nucleoside. When activated guinea pig polymorphonuclear leukocytes were stimulated with phorbol myristate acetate to produce hypochlorite, they actively incorporated [14C]adenosine into acid-insoluble products by a process that was dependent on oxygen and inhibited by azide and thiols. These findings suggest that adenine nucleotide chloramines are generated by activated phagocytic cells and form ligands with proteins and nucleic acids as observed in model systems. The results imply that nucleotide chloramines are among the cytotoxic and possibly mutagenic factors that are associated with the inflammatory process.

Continuous removal of leucocytes during early gram-negative septicemia reduces plasma levels of endotoxin and improves cardiac performance

The effect of filter leucapheresis as treatment of gram-negative septicemia was studied in an experimental porcine model. In 7 matched pairs of animals, one of the animal groups received filter leucapheresis starting 2 h after the induction of septicemia. The other animal group acted as a non-treated control. A calculated mean number of 15 x 10(9) white blood cells were removed. Animals submitted to leucapheresis showed lower levels of circulating endotoxin, diminished degree of granulocyte activation and higher cardiac output when compared to the non-treated controls. The increased cardiovascular performance indicated a beneficial effect of selective leucafiltration during early gram-negative septicemia. Lower levels of circulating endotoxin and less active PMNs might contribute to these changes.