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Biomedical subjects

B Ashe

Publications and source records attributed to B Ashe.

5 recordsLinked to original sources
PubMed1991

Karyological approach to the identification of true cell lines susceptible to the human immunodeficiency virus (HIV).

A karyological analysis of twenty-two variants of eight cell lines, which differed in their susceptibility to the human immunodeficiency virus (HIV) and which had been obtained from different sources, was carried out by means of differential chromosome staining for G and C bands. The karyotypes of eight T-lymphoblastoid cell lines were identified, including five (MT-4, Molt-3, CEM, H-9, and Hut-78) not previously studied by cytogenetic methods. Karyotyping confirmed the identity of seventeen variants of the eight cell lines, and five variants of four lines were found to be misidentified. Comparative analysis of the cytogenetic characteristics of the three CEM-line variants demonstrates the need for karyotype evaluation in the course of in vitro cell cultivation. Fourteen identical marker chromosomes were revealed in H-9 and Hut-78 cell karyotypes, confirming the common origin of these two lines. It was found that the cells of the HIV-susceptible lines had a tendency to undergo polyploidisation both during the initial stages after isolation and in the course of cultivation.

Cell Line↗
PubMed1989

Pharmacological profile of the substituted beta-lactam L-659,286: a member of a new class of human PMN elastase inhibitors.

Human polymorphonuclear leukocyte elastase (PMN elastase) is inhibited by L-659,286 (7 alpha-methoxy-8-oxo-3-[[(1,2,5,6-tetrahydro-2-methyl-5,6-dioxo-1,2,4- triaz-in-3-yl)thio]methyl]-5-thia-1-aza-6R-bicyclo[4.2.O]oct-2-ene -2- pyrrolidine carboxamide-5,-dioxide) with a Ki of 0.4 microM. This inhibition is time-dependent, rapid, and only slowly reversible, with a t1/2 of greater than 3 days at 25 degrees C. L-659,286 is also highly selective for PMN elastase, as it does not inhibit thrombin, trypsin, papain, plasmin, chymotrypsin, or cathepsin G. L-659,286 administered intratracheally inhibits lung damage caused by administration via the same route of human PMN elastase into hamsters. In marmosets, L-659,286 is cleared from blood very rapidly after an intravenous injection but is recovered in bronchoalveolar lavage fluid for several hours after intratracheal administration.

Animals↗
PubMed1979

Characterization of an endopeptidase involved in pre-protein processing.

Proteolytic removal of the pre-segment from growing nascent chains of pre-human placental lactogen (hPL) occurred during in vitro translation of placental mRNA if crude membranes derived from ascites lysates, dog pancreas, or rat liver rough endoplasmic reticulum were added to the translation mixtures. The cotranslational proteolytic event was inhibited by the peptide protease inhibitor, chymostatin, but not by leupeptin, antipain, or elastatinal. The proteases involved in cleavage were solubilized with detergent and converted completed pre-hPL to hPL (post-translational processing). Direct assay of the solubilized membranes, with synthetic fluorogenic aminocoumarin peptide substrates, revealed no significant tryptic or elastase-like activity, but activity against a chymotrypsin substrate [(succinyl-Ala-Ala-Phe)-7-amino-4-methyl-coumarin] was found. This activity was dependent upon both an endopeptidase and an aminopeptidase. Although bestatin inhibited the aminopeptidase activity, it had no effect on the endopeptidase or on post-translational cleavage. Although this endopeptidase cleaved on the COOH side of an alanine residue, it was not inhibited by elastatinal. However, it was inhibited by high levels of chymostatin and by some serine protease inhibitors.

Animals↗
PubMed1978

Direct fluorescent assay of urokinase and plasminogen activators of normal and malignant cells: kinetics and inhibitor profiles.

A direct rate assay for plasminogen activator has been developed using a synthetic fluorogenic peptide substrate, 7-(N-Cbz-glycylglycylargininamido)-4-methylcoumarin trifluoroacetate. The assay correlates well with the standard 125I-labeled fibrin plate assay using highly purified urokinase, culture fluids from WI-38, Chinese hamster vary or HeLa cells, or Rous sarcoma virus-transformed chick fibroblasts as the source of plasminogen activator. The assay is sensitive, rapid, and linear throughout a wide range of enzyme concentrations. With this substrate it is possible to determine inhibitor profiles for the various plasminogen activators, independently of the interfering potential of plasmin. All of the enzymes tested are inhibited by leupeptin and antipain but not by the related aldehydes, elastatinal and chymostatin. The macromolecular inhibitors soybean trypsin inhibitor and trasylol have little or no effect on the plasminogen activators tested. This substrate should be useful for the study of the effect of various agents on functional changes in cells secreting this enzyme and also should allow kinetic measurements of potential inhibitors.

Animals↗