ozagrel and Streptococcal-Infections

Group B streptococci (GBS) localizing in the lungs of infant piglets is killed in part by an oxygen radical-dependent mechanism (Bowdy BD, Marple SL, Pauly TH, Coonrod JD, Gillespie MN: Am Rev Respir Dis 141:648-653, 1990). The source of bactericidal oxygen radicals is unknown, but cyclooxygenation of arachidonic acid, an initial event in prostanoid synthesis, is accompanied by substantial oxygen radical generation. Because blockade of prostaglandin H synthase (cyclooxygenase) with indomethacin prevents GBS-induced pulmonary hypertension, we reasoned that the salutary effect of indomethacin might be associated with a reduction in the efficacy of bactericidal activity directed against GBS. To address this possibility, the distribution and viability of 111In-labeled GBS (10(8) colony forming units/kg/min i.v. for 15 min) were assessed in lungs and livers of control piglets, piglets treated with indomethacin (1 mg/kg), and piglets treated with OKY-046 (10 mg/kg), an inhibitor of thromboxane synthase that also forestalls GBS-induced pulmonary hypertension. Relative to control animals, indomethacin treatment increased pulmonary GBS uptake with no change in bacterial distribution into the liver. OKY-046 failed to influence pulmonary bacterial uptake but promoted a substantial increase in GBS depositing in the liver. In contrast to its effects on pulmonary bacterial deposition, indomethacin failed to increase lung bacterial viability relative to control animals. Indomethacin also was without effect on hepatic bacterial viability. OKY-046 failed to influence pulmonary bacterial viability but markedly augmented hepatic GBS viability to the extent that significant bacterial proliferation occurred.(ABSTRACT TRUNCATED AT 250 WORDS)

Topics: Animals; Free Radicals; Hypertension, Pulmonary; Indomethacin; Liver; Lung; Methacrylates; Prostaglandins; Streptococcal Infections; Streptococcus agalactiae; Swine; Thromboxanes

The role of thromboxane (Tx) A2 in Streptococcus pneumoniae-induced granulocytopenia, thrombocytopenia, and pulmonary leukostasis is unclear. Rabbits were injected with 0.85% NaCl, nonviable pneumococci, or nonviable pneumococci after pretreatment with TxA2 synthetase inhibition. Blood was obtained immediately before and at times after injection for granulocyte and platelet counts and assays of TxB2 and 6-keto prostaglandin F1 alpha (6-ketoPGF1 alpha). Animals were evaluated for pulmonary leukostasis histologically and biochemically (myeloperoxidase activity). Pneumococcal challenge induced significant granulocytopenia (P less than .001), thrombocytopenia (P less than .001), and elevations in levels of both TxB2 (P less than .05) and 6-ketoPGF1 alpha (P less than .001) as well as pulmonary leukostasis (P less than .001). TxA2 synthetase inhibition blocked the pneumococcus-induced elevation in level of TxB2 without significantly altering levels of circulating granulocytes, platelets, or 6-ketoPGF1 alpha. Pulmonary leukostasis was not blocked. In another group of pneumococcus-challenged animals, no significant transpulmonary gradients of either TxB2 or 6-ketoPGF1 alpha were found.

Topics: 6-Ketoprostaglandin F1 alpha; Agranulocytosis; Animals; Epoprostenol; Lung; Methacrylates; Rabbits; Streptococcal Infections; Thrombocytopenia; Thromboxane B2; Thromboxane-A Synthase; Thromboxanes