Until recently, it has been generally assumed that the conversion under highly aerobic conditions of relatively simple, non-nitrogenous compounds by washed suspensions of bacteria is limited to an oxidation of the substrate to carbon dioxide and water. Barker (1936), Geisberger (1936) and Clifton (1937) have shown that the oxidation does not proceed to completion, but that instead, a portion of the substrate is apparently assimilated by the cells. For example, the oxidative assimilation of acetate and of butyrate by Pseudomonas calco-acetica may be represented as 2CH3COOH + 302 = (CH20) + 3 C02 + 3H20, (1) and 2C4H802+ 702 = 3 (CH20) + 5 C02 + 5H20 (2) These equations indicate that approximately three-fourths of the oxygen required for the complete combustion of these substrates is consumed, with the production of carbon dioxide, water and a substance, or substances, having the empirical composition of a carbohydrate. The oxidative assimilation of butyrate is of particular interest since the respiratory quotient (R.Q.) during the stage of rapid oxidation is approximately 0.68 while the theoretical R.Q. for complete combustion is 0.8. The rate of oxygen consumption abruptly decreases to a level near that of the control by the 523

Interferon-gamma (IFN-gamma) has been shown to have immunoregulatory properties and is able to modulate resistance to several microbial infections. This study was designed to determine the efficacy of IFN-gamma treatment in a murine burn wound infection model. Bacterial challenge consisted of Klebsiella pneumoniae (10(8) organisms/ml) or Pseudomonas aeruginosa (10(8) organisms/ml), applied topically immediately after burning. Groups of CBA/J mice received either IFN-gamma or RPMI-1640 medium (controls) subcutaneously. IFN-gamma was administered daily at a dose of 7,500 units for 5 days prior to bacterial challenge. Burn without bacterial challenge produced no mortality. Mice treated with IFN-gamma survived significantly longer than controls when the bacterial challenge was K. pneumoniae. There was no difference in survival when bacterial challenge was P. aeruginosa. The Ia antigen expression of peripheral blood mononuclear cells was severely reduced for 3 days post-burn. This drop was prevented on day 3 post-burn in mice treated with IFN-gamma. These data indicate that interferon was effective treatment in a murine model of Klebsiella burn wound infection and was associated with maintenance of Ia antigen expression that may have contributed to the action of the IFN-gamma.

No abstract

No abstract

No abstract