Biomedical subjects
Publications and source records attributed to J R Tyler.
Lancaster General Hospital in 1991 surveyed graduates of its 21-year-old Family Practice Residency on a number of medical and non-medical issues. The results, overviewed in this article, may lay the groundwork for future efforts to obtain a national consensus regarding family practice education in its current format.
Ten ovarian and 2 cervical tumour cell lines were analysed for the production of pregnancy-associated proteins. Pregnancy-associated plasma protein-A (PAPP-A) was detected by radioimmunoassay in culture media of 2 out of 4 (50%) tumour granulosa cell lines (mean = 104 microIU/10(5) cells/24 h) but not in any ovarian (n = 6) or cervical (n = 2) tumour cell lines. By contrast, human chorionic gonadotrophin (hCG), pregnancy specific beta 1-glycoprotein and alpha-fetoprotein (AFP) were not detected in any of the PAPP-A positive media. Only two cell lines produced hCG (58.5 and 25.5 mIU/10(5) cells/24 h). No AFP was produced by any of these 12 cell lines, whereas placental protein 5 was positive in 7. None of these proteins were detected in the culture media of 4 cell lines. In vitro derived PAPP-A was immunologically indistinguishable from either pregnancy or ovarian follicular PAPP-A. All PAPP-A species interacted reversibly with immobilised heparin and were determined by molecular sieve chromatography to have an apparent molecular weight of 820,000 daltons. Cultured tumour granulosa cells specifically synthesised and secreted a large protein which was immunologically and physicochemically indistinguishable from in vivo (pregnancy and ovarian follicular) derived PAPP-A.
A radioimmunoassay for the measurement of placental protein 5 (PP5) has been developed using a second antibody-polyethyleneglycol method to separate free from bound ligand. PP5 immunoreactivity was detected in culture media from a cell line derived from a small cell carcinoma of the ovary (SCCWm2). The culture-derived PP5 shares immunological identity with pregnancy and ovarian follicular PP5. Affinity interactions between PP5 and matrices such as heparin or thrombin-Sepharose were similar and independent of the origin of PP5. PP5 was heterogeneous with two forms, a monomer (18k) and dimer (36k) being detected in all biological fluids examined. The dimer was predominant in ovarian follicles and the SCCWm2 cell line, while the monomer predominated in pregnancy serum. The basal rate of PP5 secretion by the SCCWm2 cell line was 0.61AU/24h/10(5) cells. Incubation of cells in the presence of 150mIU Pergonal stimulated PP5 production 20.6 fold and following removal of Pergonal the production rate was maintained at 18.0 times the basal rate. No choriconic gonadotrophin, pregnancy-specific beta 1-glycoprotein, pregnancy associated plasma protein-A or alpha fetoprotein was detected in the culture medium of the SCCWm2 cell line.
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