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Biomedical subjects

P Actor

Publications and source records attributed to P Actor.

66 records · Page 4Linked to original sources
PubMed1973

Immunity to Vibrio cholerae in the mouse. II. Effect of a cell-adherent immune factor.

Serum, peritoneal exudate cells, or spleen cells were obtained from donor mice immunized with Vibrio cholerae Ogawa 41. Normal recipients were protected from lethal Vibrio infection when challenged one day after transfer of immune serum or peritoneal cells or normal peritoneal cells exposed in vitro to immune serum. Protection of recipients of immune spleen cells was evident when the cell transfer-challenge interval was 14 days but not when it was 1 day. Transfer of immunity with peritoneal cells from actively immunized donors was long lasting, whereas that derived from in vitro treatment of normal cells was of short duration. Both a cell-adherent and a nonadhering immune factor appear to be important in this immunity.

Animals↗
PubMed1972

Immunity to Vibrio cholerae in the mouse. I. Passive protection of newborn mice.

Mice were immunized subcutaneously with either killed cells or a ribosome-containing fraction (RF) obtained from Vibrio cholerae Ogawa 41. At appropriate time intervals, these mice or their progeny were challenged with uniformly lethal doses of Ogawa or Inaba serotype. Half of the offspring born to mice immunized with 20 mug of RF were protected against homologous challenge at 7.5 weeks of age, and significant protection was observed up to 15 weeks of age. Similar protection was observed with heterologous challenge, but the duration of protection was reduced. The duration of protection obtained in newborns was related to the quantity of RF given to the mother. Protection was transferred from mother to young via colostrum or milk. Protection was not due to transfer of antigen, as active immunity could not be induced in newborn mice immunized with RF.

Animals↗
PubMed1972

Isolation of protective somatic antigen from Vibrio cholerae (Ogawa) ribosomal preparations.

Ribosomal preparations from Vibrio cholerae Ogawa and Inaba are protective immunogens for mice challenged with either serotype. Column chromatography of ribosomal fractions separated protective antigen from the ribosomes. The antigen is a heterogeneous colloid which contains protein, lipid, and carbohydrate in the ratio 3:1:1. Amino acid composition is that of a slightly acidic protein with no unusual complement of amino acids. The lipid component consists of several longchain fatty acids and of phosphatidyl ethanolamine. The major sugars identified were glucose and galactose. The colloid can be dissolved by treatment with chelating agents and sodium dodecyl sulfate. Purification of the solubilized material or of the colloid was unsuccessful.

Amino Acids↗
PubMed1971

Comparison of the effects of a synthetic polyribonucleotide with the effects of endotoxin on selected host responses.

An injection of a small dose (1 to 50 mug) of synthetic polyriboinosinic acid complexed with polyribocytidylic acid (poly I:poly C) inhibited the induction of tryptophan oxygenase by cortisone acetate; it induced tyrosine amino transferase, and it accelerated the loss of liver glycogen reserves. It also resulted in first a suppression followed by an activation of the reticuloendothelial system as judged by the rates of carbon clearance from blood. All of these responses are elicited by comparable doses of endotoxin. Pretreatment of mice with poly I:poly C did not, or only marginally, increased their nonspecific resistance to infection with several bacterial pathogens, and it failed to result in the development of tolerance to endotoxin, effects known to be produced by endotoxin when given under similar conditions.

Journal Article↗
PubMedDate not supplied

Efficacy of the hematoregulatory peptide SK&F 107647 in experimental systemic Candida albicans infections in normal and immunosuppressed mice.

SK&F 107647, a novel synthetic dimeric pentapeptide, has been shown to be a potent hematoregulatory agent. The potential for the hematoregulatory factors elicited by SK&F 107647 to confer protection in experimental models of systemic Candida albicans infection was evaluated in immunosuppressed and immunocompetent mice. Prophylactic treatment with recombinant human interleukin-1 (rhIL-1), recombinant human granulocyte colony stimulating factor (rhG-CSF), or the hematoregulatory peptide SK&F 107647 significantly increased survival times in gamma irradiated immunosuppressed as well as non-irradiated immunocompetent mice challenged with a lethal dose of C. albicans. Protection was also observed in athymic nu/nu "nude" mice. Additionally, significant increases in survival in non-irradiated immunocompetent mice dosed by oral gavage were observed. These results indicate that SK&F 107647 can significantly enhance natural host resistance to experimental C. albicans infections both in immunosuppressed and immunocompetent mice.

Animals↗
PubMedDate not supplied

In vitro experience with cefonicid.

Cefonicid was found to be highly active in vitro against greater than 5,000 bacterial isolates. Its spectrum of activity was similar to that observed with cefamandole, including both gram-positive and gram-negative pathogens. No significant activity was observed against methicillin-resistant staphylococci, enterococci, Pseudomonas, Serratia, Acinetobacter, and Bacteroides species. Studies in which susceptibility disks containing 30 micrograms of cefonicid, cefamandole, or cephalothin were used and zone sizes were plotted against MIC values resulted in similar regression lines. Interpretive breakpoints were less than or equal to 14 mm for defining resistance and greater than or equal to 18 mm for defining susceptibility. The results for isolates tested with cefonicid susceptibility disks were highly predictive of clinical efficacy. On the basis of the observed pharmacokinetics of cefonicid at the usual single daily dose of 1 g, a bacterial strain is considered susceptible if the MIC values are not greater than 16 micrograms/ml. Organisms with MICs greater than 32 micrograms/ml are considered resistant. The profile of the stability of cefonicid to hydrolysis by beta-lactamases is similar to that observed with cefamandole. The affinity of cefonicid to the penicillin-binding proteins of Escherichia coli also resembled that of cefamandole, with its greatest affinity for penicillin-binding proteins 1a, 3, and 1b, in that order.

Anti-Bacterial Agents↗