Effects of blood on blood culture medium.

The morphological and biochemical changes that occur after inoculation of sterile blood into a blood culture medium (tryptic soy broth) with sodium polyanetholesulfonate and CO(2) were investigated. Cellular changes, pH, PCO(2), and PO(2) were monitored and evaluated. Erythrocytes became crenated and developed precipitated hemoglobin inclusions within 4 h. The lymphocytes appeared morphologically intact at 24 h, and by 48 h a few cells had undergone transformation. Many neutrophils were vacuolated at 24 h. Neutrophils capable of phagocytizing Staphylococcus aureus were observed after 18 h of incubation. Identifiable eosinophiles were present on day 6 of the study. A decrease in PO(2) in the unvented bottles from 44.4 to 8 mm of Hg occurred by 24 h. PO(2) remained low for 6 days, after which a slight increase occurred. An increase in PO(2) in the vented bottle from 51 to 58 mm of Hg occurred by 24 h of incubation. In both the vented and unvented bottles the PCO(2) increased. This increase was markedly more rapid in the unvented bottle. From a pH of 7.06 a decrease occurred for the first 24 h after inoculation, with the pH stabilizing at 6.8 in the vented bottles and at 6.6 in the unvented bottles. The biochemical changes that occurred in the vented culture bottles stabilized more rapidly than those of the unvented bottles. Changes caused by the addition of sterile blood to a blood culture medium resulted in conditions which departed considerably from accepted optima for the isolation of clinically important microorganisms. The phagocytosis of organisms that occurred may also have reduced the yield.

Pneumocystis carinii pneumonia. An approach to rapid laboratory diagnosis.

Laboratory procedures used to establish the diagnosis of Pneumocystis carinii pneumonia were evaluated using an experimental murine model. Touch preparations and suspension smears were prepared from lung tissue know to contain Pneumocystis cysts. These preparations were stained by a variety of methods known to demonstrate either cyst forms or sporozoites and trophozoites. Suspension smears proved to be superior to touch preparations in terms of cyst content and homogeneity of staining. Also, methods that stain cyst forms were superior to those that stain sporozoites and trophozoites for location and identification of organisms. The authors believe that suspension smears prepared from lung tissue and stained with toluidine blue O should be examined initially as a rapid screening method for Pneumocystis cysts. When the results of this initial screen are negative or inconclusive, additional suspension smears stainded by the modified Gomori methenamine silver nitrate method should be examined, pending availability of histologic sections.

Antioxidants reduce the mutagenic effect of malonaldehyde and beta-propiolactone. Part IX. Antioxidants and cancer.

Increasing concentrations of malonaldehyde and beta-propiolactone were increasingly mutagenic with 7 mutants of Salmonella typhimurium, 5 of which mutated bya frameshift mechanism and 2 of which mutated through base-pair substitution. The antioxidants vitamin C, vitamin E, selenium and butylated hydroxytoluene (BHT) at 3 logarithmic concentrations markedly reduced mutagenesis in those strains which mutated by frameshift mechanism.