Biliary excretion of a new semisynthetic cephalosporin, cephacetrile.

The biliary excretion of a new derivative of cephalosporin, cephacetrile (CIBA 36 278 Ba), was studied (i) in the isolated perfused rabbit liver, (ii) in humans with a duodenal tube, and (iii) in patients after cholecystectomy with a Kehr's drain in the common bile duct. The biliary excretion of the antibiotic was very low in the perfused liver, and no antibiotic activity was found in liver tissue at the end of the experiment. This observation, together with the finding of a rapid decline of the antibiotic concentration in the circulating blood serum, favors the assumption that a metabolic transformation of CIBA 36 278 Ba in liver tissue takes place.

Studies on human antibodies. VI. Selective variations in subgroup composition and genetic markers.

The composition of various isolated antibodies was determined by quantitative analyses for heavy chain subgroups and light chain types. Certain antibodies such as anti-tetanus toxoid and anti-A isoagglutinins were predominantly of the major gammaG1-type. However, a high preponderance of molecules of the minor gammaG2-subgroup was found for antibodies to dextran, levan, and teichoic acid.

Studies on human antibodies. V. Amino acid composition of antidextrans of the same and of differing specificities from several individuals.

Human dextran-antidextran-specific precipitates from individuals immunized with dextrans containing either one or two antigenic determinants, were analyzed for their content of various amino acids. Large differences in certain amino acids were found among alpha-(1 --> 6)-specific antidextrans. Wide variations were also observed in antidextran fractions from a given individual specific for alpha-(1 --> 6)- and alpha-(1 --> 2)-linked glucose residues.