Biomedical subjects

C Pyke

Publications and source records attributed to C Pyke.

41 records · Page 3Linked to original sources

PubMed1990

Plasminogen activator inhibitor-type 1 in Lewis lung carcinoma.

Plasminogen activator inhibitor-type 1 (PAI-1) was identified in extracts of Lewis lung carcinoma, and its immunohistochemical localization was studied together with that of urokinase-type (u-PA) and tissue-type (t-PA) plasminogen activators. All primary tumors (n = 11) contained heterogeneously distributed immunoreactivity against each of the three components. Most often, areas that contained u-PA immunoreactivity also contained PAI-1 immunoreactivity. However, several areas showed a strong u-PA immunoreactivity, but no or low PAI-1 immunoreactivity. The latter staining pattern was only found in peripheral areas, and usually in areas with histological signs of tissue destruction. Lung metastases always contained u-PA immunoreactivity, while PAI-1 immunoreactivity was found in most, but not all, metastases. t-PA immunoreactivity was found in a few scattered tumor cells, in primary carcinomas as well as metastases. Controls that included absorption with highly purified antigen preparations and immunoblotting, indicated that all the immunoreactivity represented genuine PAI-1, u-PA and t-PA, respectively. The results are consistent with an assumption that the plasminogen activation system, and particularly u-PA and PAI-1, plays a role in regulation of breakdown of extracellular matrix proteins during invasive growth in this carcinoma.

Animals↗

PubMed1989

Plasminogen activator inhibitor (type-1) in rat adrenal medulla.

Plasminogen activator inhibitor type-1 (PAI-1) was identified in extracts of rat adrenal medulla, and its immunohistochemical localization was studied together with that of tissue-type plasminogen activator (t-PA). By staining of adjacent sections and by double-staining of the same section we demonstrate that the same cells of the adrenal medulla contain both PAI-1 and t-PA immunoreactivity in the cytoplasm. In addition a few ganglion cells of the adrenal medulla were found to contain PAI-1 but not t-PA. Neither of the components were found in the adrenal cortex. Analysis of extracts from isolated adrenal medulla using reverse zymography showed the presence of a plasminogen activator inhibitor with Mr approximately 46,000. The inhibitory activity disappeared when the extract was passed through a column with sepharose-coupled anti-PAI-1 IgG, while the run-through from a similar column coupled with preimmune IgG still contained the inhibitor. The present findings suggest that PAI-1 could play a role in the regulation of t-PA activity in the rat adrenal gland medullary cells.

Adrenal Medulla↗

PubMed1987

Isolation of oxfendazole resistant Cooperia oncophora in cattle.

A field strain of Cooperia oncophora resistant to oxfendazole was isolated from a commercial cattle rearing property in Waikato, New Zealand. Resistance to oxfendazole was assessed by means of a faecal egg count depression test and an in vitro egg hatch test. This is the first documented case of anthelmintic resistance in Cooperia spp. and the first report of anthelmintic resistance in cattle in New Zealand.

Journal Article↗

PubMed1987

Plasminogen activator inhibitor type 1 biosynthesis and mRNA level are increased by dexamethasone in human fibrosarcoma cells.

Dexamethasone increases type 1 plasminogen activator inhibitor (PAI-1) activity released from the human fibrosarcoma cell line HT-1080. We demonstrated that dexamethasone caused about 10-fold increases in the intracellular and extracellular levels of PAI-1 protein, as measured by an enzyme-linked immunosorbent assay, in the rate of PAI-1 biosynthesis, and in the PAI-1 mRNA level. The effects on PAI-1 biosynthesis and mRNA level were detectable within 4 h and were maximal 16 to 24 h after the addition of dexamethasone. Cycloheximide did not inhibit the dexamethasone-induced increases in the capacity of the cells to synthesize PAI-1 and in the PAI-1 mRNA level.

Cell Line↗

PubMedDate not supplied

Messenger RNA for membrane-type 2 matrix metalloproteinase, MT2-MMP, is expressed in human placenta of first trimester.

An intimately regulated cell surface activation of matrix metalloproteinases (MMPs) is believed to be of critical importance for the control of trophoblast invasion. A histological investigation of the expression and localization of three different MMPs, the membrane-type matrix metalloproteinases 1 and 2 (MT1-MMP, MT2-MMP) and matrix metalloproteinase 2 (MMP-2/gelatinase A) was performed by in situ hybridization on consecutive sections from human placentae of first trimester pregnancies. Cytokeratin immunostaining identified trophoblast cells. Both normal and tubal implantation sites were studied. We observed a high degree of coexpression of MT2-MMP, MT1-MMP and MMP-2 mRNAs in single extravillous cytotrophoblasts that had invaded the endometrium and tubal wall. Furthermore, mRNAs for all three genes were also seen in cytotrophoblasts of cell islands. In contrast to this coexpression pattern, MT2-MMP expression was absent from cell columns and decidual cells, in which signals for MT1-MMP and MMP-2 mRNAs were seen. The present data on the cellular expression of MT2-MMP mRNA in placenta extend our knowledge of the proteolytic events that take place during early pregnancy. The data suggest that MT2-MMP, capable of activating MMP-2 in vitro, is involved in the invasion of extravillous cytotrophoblast, possibly related to the physiological activation of MMP-2.

Enzyme Activation↗