No abstract

Since NZB/NZW mice develop an immune nephritis similar t o that of systemic lupus erythematosus in man, a study was designed in these mice to compare the clinical and immunologic effects of three immunosuppressive drug regimens. For 72 weeks, groups of 20 mice received daily oral therapy with a) no drugs, b) azathioprine, c) prednisolone or d) combined azathioprine-prednisolone. The combined regimen was superior t o either drug used alone in preventing deaths from renal disease. Prednisolone alone also prolonged life significantly, but not as effectively as combination therapy. Azathioprine alone was not effective. All drugs suppressed the antibody response to an exogenous antigen (Vi polysaccharide) equally well. None of the drug regimens prevented the appearance of proteinuria, antinuclear antibodies, Coombs' antibody, or 7-globulin deposits in glomeruli. However, the ability of a therapeutic regimen t o suppress antibodies to native DNA correlated well with its ability t o suppress renal disease. No malignancies were found among 73 animals autopsied, but significant hepatic damage occurred in the groups receiving prednisolone. Thus, combined therapy was superior t o either drug used alone, and the immunosuppressive effect of greatest clinical importance seemed to be the ability to prevent formation of anti-DNA antibodies.New Zealand black and New Zealand white hybrid mice (NZB/NZW F,) spontaneously develop a disease quite similar to systemic lupus erythematosus (SLE) in man. Virtually all mice of this strain develop lethal, immune complex

The hydrogen sulfide-negative Citrobacter group represents a taxonomic problem. Various investigators have proposed such designations as Padlewskia, Levinea, atypical Enterobacter cloacae, H2S-negative variants of Citrobacter, Citrobacter koseri and Citrobacter diversus. This problem has been investigated with emphasis on antibiograms as a means of discrimination. Clinical isolates fitting the designation Citrobacter were studied and, using the criteria of Ewing and Davis, separated into two groups: C. diversus (40 strains) or C. freundii (25 strains). Susceptibilities to ampicillin, carbenicillin, cefazolin, cephaloridine and cephalothin were determined by the agar-dilution method. C. diversus strains were resistant to 8 mug/ml ampicillin (97.5%) and 32 mug/ml carbenicillin (87.5%), and were susceptible to 8 mug/ml cephalosporins (greater than or equal to 90%). C. freundii strains were moderately susceptible to 8 mug/ml ampicillin (25%) and susceptible to 8 mug/ml carbenicillin (92%), and were resistant to 8 mug/ml cephalosporin (greater than or equal 92%). Using these data one can separate C. diversus from C. freundii with 90% accuracy.