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PubMed1963

[SULFONAMIDES].

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4-Aminobenzoic Acid↗
PubMedDate not supplied

On the relation between the formation of antihapten and anti-carrier protein antibodies in the immune response induced by conjugates of various haptens with homologous serum proteins.

Rabbits inoculated with conjugates of homologous serum with ortho-aminophenol (OAP), para-aminophenol (PAP), 3-hydroxy-sulfanilamide (3-HS), DOPA and alpha-methyldopa (alpha MD), 5-aminosalicylic acid (5-ASA) and 3-hydroxy-para-aminobenzoic acid (3-HPABA) give rise to both hapten specific and anti-carrier protein antibodies. By contrast, the conjugates of homologous serum with penicilloyl (P) hapten induced only antihapten antibodies. The conclusion is, therefore, drawn that the formation of anti-carrier antibodies upon inoculation with conjugates of various haptens appears to be dependent on the nature of hapten in the conjugate. The discrepancy between the behaviour of P conjugates, on the one hand, and the DOPA and alpha MD conjugates, on the other hand, is in agreement with the observation from the clinical immunology, which has signaled a high incidence of antibodies with autoantibody character in patients taking DOPA and alpha MD, but rarely, if ever, such antibodies have been found in patients treated with penicillin.

Animals↗
PubMed1988

The effect of exocrine pancreatic function on chloramphenicol pharmacokinetics in patients with cystic fibrosis.

The effect of exocrine pancreatic function on the pharmacokinetics of the choramphenicol oral capsule (CAP-base), chloramphenicol palmitate oral liquid (CAP-P), and chloramphenicol succinate intravenous (CAP-S) formulations was evaluated in 10 patients, aged 16-30 yr, with cystic fibrosis. Pancreatic insufficiency was assessed in each patient by measuring the absorption of p-amino-benzoic acid after oral administration of N-benzoyl-L-tyrosyl-p-aminobenzoic acid which requires chymotrypsin to cleave p-aminobenzoic from the parent molecule. In a controlled cross-over design, the overall biodisposition of each formulation was assessed in each patient with or without concurrent administration of oral pancreatic enzymes. The relative amounts of active chloramphenicol available in systemic circulation was CAP-base greater than CAP-S greater than CAP-P. Pancreatic enzyme replacement had little effect on the biodisposition parameters for the CAP-base and CAP-S formulation, but significantly increased the peak concentration and bioavailability of the CAP-P formulation. Although pancreatic enzyme replacement improved the absorption characteristics of the CAP-P formulation, absorption remained prolonged and unreliable. Serum concentration-time profiles for either CAP-base or CAP-S consistently exceeded the MIC of important nonpseudomonal pathogens. This finding was not observed after CAP-P administration independent of pancreatic enzyme replacement. The results of this study support the continued clinical use of either CAP-base or CAP-S, but the cautious use of CAP-P formulations in CF patients with concurrent pancreatic insufficiency.

Administration, Oral↗
PubMed1991

Chemical modification of PABA synthase.

p-Aminobenzoic acid (PABA) synthase catalyses the first step in folic acid biosynthesis, the conversion of chorismate to p-aminobenzoate. In general, difficulties in purification have permitted only limited investigation of this enzyme. However, in an attempt to identify possible active site residues, the E. coli enzyme has been incubated with a range of protein modifying agents. Results indicate that cysteine, histidine, arginine and tyrosine residues are important for enzyme activity. Attempts were made to determine the subunits upon which these residues were located.

Arginine↗
PubMed1983

Folate deficiency in rats fed amino acid diets.

Growth rate, hematological changes, serum, erythrocyte and liver folate levels, and urinary excretion of formiminoglutamic acid (FIGLU) were measured in rats fed p-aminobenzoic acid (PABA)-free, sulfonamide-supplemented purified amino acid diets with and without folic acid and fiber, individually and in combination. Fiber had no effect on growth but was necessary to prevent mortality in the absence of folic acid. Folic acid did not affect growth during the first 40 days, but after this period rats failed to gain weight in the absence of folic acid. Although blood hematocrit was lower when the diet was devoid of fiber and folic acid and leucocyte counts were lower when the diets were devoid of folic acid, the hematological values remained within normal physiological limits for healthy rats of comparable age. FIGLU excretion was increased and serum, erythrocyte and liver folate levels were depressed when rats were fed folic acid-free diets for 28 days. Neutrophil hypersegmentation was clearly evident after 28 days of feeding the folic acid-free diets. The use of an amino acid diet without PABA but containing 5% fiber and 1% succinylsulfathiazole is a useful system to study chronic folic acid deficiency in the rat.

Amino Acids↗
PubMed1966

Mechanism of adenine inhibition in adenine-sensitive mutants of Salmonella typhimurium.

Dalal, Fram R. (University of Pennsylvania, Philadelphia), Ronald E. Gots, and Joseph S. Gots. Mechanism of adenine inhibition in adenine-sensitive mutants of Salmonella typhimurium. J. Bacteriol. 91: 507-513. 1966.-The inhibition of growth of Salmonella typhimurium by adenine was studied with three adenine-sensitive mutants. These mutants were acutely sensitive to inhibition by adenine, were prototrophic in their growth requirements, and represented mutational events in three different genetic loci. In all cases, inhibition by adenine was relieved noncompetitively by thiamine (or its pyrimidine moiety), pantothenate (or its pantoyl moiety), and methionine alone or, more efficiently, in the presence of lysine. Kinetics of reversal indicated that adenine inhibited the synthesis of the reversing agents, probably at the level of a common factor required for their syntheses, such as the folic acid coenzymes. Support for this inference has been found by the facts that one of the mutants was identified as a partial auxotroph for p-aminobenzoic acid, and sulfadiazine could sensitize the wild type to acute inhibition by adenine.

Adenine↗
PubMed1991

2-Nitro-5-(6-bromohexanoylamino)benzoic acid test paper method for detecting microorganisms capable of producing cephalosporin acylases.

A novel method for detecting microorganisms capable of producing cephalosporin C (CPC) acylase and/or 7-(4-carboxybutanamido)cephalosporanic acid (GL-7-ACA) acylase has been developed. The method is based on the degradation of 2-nitro-5-(6-bromohexanoylamino)benzoic acid (NBHAB), a chromogenic substrate, into yellow 2-nitro-5-aminobenzoic acid by the action of the CPC acylase or the GL-7-ACA acylase. This method is very sensitive and quite specific, and has been successfully applied to screen the acylases from a variety of bacteria. A large number of colonies isolated on a plate surface from more than 67 samples and several known bacteria were tested by the NBHAB paper. Five NBHAB-positive strains and isolates were obtained. They were further examined by the reaction of their bacterial cells upon CPC and GL-7-ACA, respectively, and by thin-layer chromatography in order to distinguish the CPC acylase from the GL-7-ACA acylase.

Agar↗