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Biomedical subjects

C A Ramthun

Publications and source records attributed to C A Ramthun.

5 recordsLinked to original sources
PubMed1981

Inhibition of mast-cell degranulation by chemotactic peptides.

Pepstatin and f-methionyl peptides which are potent chemotactic agents for neutrophils were found to inhibit the increase in vascular permeability of rat skin which follows the injection of 48/80, anti-rat IgE serum, or pulmonary permeability factor. These latter compounds are known to act by releasing histamine from mast cells. f-Met-Leu-Phe, which is the most active chemotactically, was also found to be the most active inhibitor.

Animals↗
PubMed1981

Pulmonary polyamine permeability factor.

Acid extracts of calf lung have been found to contain low-molecular-weight factors which increase the permeability of the microcirculation when injected into the skin of rats. These factors, which were present in very low levels in aqueous extracts, were purified by gel filtration and ion-exchange chromatography. High-voltage paper electrophoresis revealed two active compounds with mobilities identical to the polyamines spermine and spermidine. Authentic samples of these compounds were as active in the "blueing" reaction as the isolated compounds. The permeability activity of both the isolated factors and the synthetic ones was inhibited by pepstatin and by pretreatment of the animals with pyrilamine maleate. If the normally low extracellular levels of these polyamines is increased by tissue damage, they could increase vascular permeability within the lung by releasing histamine from adjacent mast cells.

Animals↗
PubMed1981

Characterization and comparison of aminopeptidase activity of various strains of Mycobacterium tuberculosis.

The aminopeptidase activity of three strains of Mycobacterium tuberculosis, H37Rv, H37Ra, and M. tuberculosis from a patient, was partially purified and characterized. The activity from all three organisms was found to be very similar, if not identical. All three aminopeptidases eluted at a similar salt concentration on DEAE Bio-Gel; were active on the same synthetic and peptide substrates; had molecular weights of 75-76,000; were found to be stable between pH 5 and 8, and 4 degrees and 40 degrees C; and had a pH optimum of 7. They were inhibited by low concentrations of Hg2+, Cu2+ and Co2+; metal chelators; and 4-chloromercuribenzoic acid. A number of amino acids and several antibiotics were also found to be inhibitory. Of the antibiotics tested, rifampicin and bacitracin were the most effective.

Aminopeptidases↗