Sulfonamide concentrations were studied in 210 serum samples from 10 volunteers after ingestion of sulfacytine, sulfisoxazole, and sulfadiazine. Results obtained by chemical assay were compared with bioassay values determined by two techniques: twofold broth dilution and agar diffusion. Although the correlation for individual samples was rather poor for the twofold broth-dilution method, the agar-diffusion bioassay correlated well with chemical determinations. The agar-diffusion assay tended to "underread" the chemical assay by an amount characteristic of each drug.

Administration, Oral↗

PubMed1972

Cross-resistance of Pseudomonas to gentamicin and tobramycin.

Clinical isolates of gentamicin-resistant organisms were found to be resistant to tobramycin, a new aminoglycoside antibiotic.

Acinetobacter↗

PubMed1972

Reversibility of protein binding of penicillins: an in vitro study employing a rapid diafiltration process.

The reversibility of human serum protein binding of oxacillin, nafcillin, and cephalothin was investigated by using a diafiltration technique. While the temperature, pH, and protein concentration were kept constant, 20% of the serum volume was exchanged every 4 to 5 min. The binding of all three drugs was rapidly reversible, and the percentage of protein binding remained the same throughout the experiment.

Blood Proteins↗

PubMed1972

Correlation of increased metabolic activity, resistance to infection, enhanced phagocytosis, and inhibition of bacterial growth by macrophages from Listeria- and BCG-infected mice.

Macrophages from mice infected with facultative intracellular organisms such as Listeria monocytogenes and BCG have been shown to resist infection by antigenically unrelated intracellular bacterial parasites. This study compares phagocytosis, bacterial growth inhibition, and oxidation of glucose by macrophages from normal mice, mice infected with listeria or BCG, or mice immunized with killed listeria in incomplete Freund's adjuvant. Macrophages from listeria- and BCG-infected mice ingested more listeria; 67 and 57%, respectively, had three or more cell-associated bacteria versus 22% of controls (P < 0.001). Peritoneal macrophages from listeria- and BCG-infected animals significantly (P < 0.001 covariance analysis) inhibited growth of listeria in suspension, whereas control macrophages had no such inhibitory effect. The rate of oxidation of glucose-1-(14)C was higher in macrophages from listeria- and BCG-infected mice than from either uninfected animals or those immunized with killed listeria. During phagocytosis of killed or live bacteria, or latex particles, the rate of glucose oxidation was increased (P < 0.01). These data suggest that the cellular immunity after infection by an intracellular organism is associated with an increase in metabolic activity of macrophages, namely, an increase in the rate of glucose oxidation resulting in enhancement of phagocytosis and killing.

Analysis of Variance↗

PubMed1972

Effects of purified staphylococcal alpha toxin on the ultrastructure of human and rabbit erythrocytes.

Previous studies have suggested that the primary site of action of purified staphylococcal alpha toxin is the cell membrane. Scanning and transmission electron microscopy studies were undertaken, therefore, to define toxin-induced alterations in the surface morphology of rabbit and human red blood cells. During the prelytic lag phase, scanning electron microscopy revealed multiple discrete blisters on the surface of rabbit red blood cells; during hemolysis, cellular collapse and ghosts were seen, but most striking was the separation of large fragments of cell membrane from red blood cell surfaces. In contrast, alterations in less sensitive human red blood cells were limited to occasional fingerlike protrusions during the period of accelerated lysis. Transmission electron microscopy substantiated these changes. These studies have provided further evidence that the cell membrane is the primary site of action of staphylococcal alpha toxin.

Animals↗

PubMed1972

Infective endocarditis: past, present and future.

Explore the source record for details and available documents.

Cephalothin↗