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Biomedical subjects

B Park

Publications and source records attributed to B Park.

66 records · Page 4Linked to original sources
PubMed1981

Surface antigen (S) common to rat and mouse embryonal carcinoma cells and to pre-implantation embryos.

Five R rat embryonal carcinomas were induced by inoculating MSV into the placenta of fectotomized rats. Anti-embryonal carcinoma antisera were prepared by allogeneic or xenogeneic immunization with ascitic embryonal carcinoma cells. To remove the non-specific activity both antisera were absorbed in vivo and in vitro. By indirect immunofluorescent assay these absorbed antisera were reactive only on rat embryonal carcinomas and on undifferentiated primitive teratocarcinoma cells of C3H and 129/SV mouse. They did not react with the differentiated cells of mouse teratocarcinomas, with other rat and mouse tumors and with various normal rat and mouse tissues including spermatozoa. A positive reaction was found on mouse and rat pre-implantation embryos from the 4-cell stage to late blastocyst.

Animals↗
PubMed1978

Presence of common surface antigens(s) on endodermal tumors and embryonal tissues of rats, hamsters and mice.

Antiserum against yolk-sac carcinoma of rat was prepared in rabbits. After appropriate absorption in vitro or in vivo this antiserum was examined on different tumors and normal tissues or rat, hamster and mouse. The methods used were indirect immunofluorescence and indirect immunoperoxidase staining and cytotoxicity tests. The immune serum was found to react with the cell membrane of different rat and hamster yolk-sac carcinomas. It reacted also with the cell surface of rat hepatoma cells. By absorption on hyalin and blocking with amniotic fluid it was shown that the antigen was neither a basement membrane component nor alpha-fetoprotein. The antiserum was cytotoxic to yolk-sac carcinoma and hepatoma cells. The immune reaction was limited to the cell membrane, as observed in immunofluorescence and in immunoperoxidase staining. The specificity of the antiserum was proved by cross-absorptions with various tumor lines and by removing its activity with the soluble fraction of yolk-sac carcinoma cells. Non-endodermal rat and hamster tumor lines did not react with the anti-yolk-sac carcinoma immune serum. Most normal adult tissues, including spermatozoa, were negative, but a positive reaction was observed in ovaries and on glandular cells of the uterus. In embryonal tissues this surface antigen(s) was detected in the endoderm of 8-day-old rat embryos 7-day-old mouse embryos and in yolk-sac endoderm of both species. The data indicate that the antigen(s) is associated with endodermal differentiation.

Animals↗
PubMed1978

Immunological enhancement of hybrid teratomas derived from yolk sac.

Visceral yolk sac displaced outside the uterus after fetectomy differentiates into benign teratomas. This differentiation only occurs in a syngeneic pregnancy but never in hybrid pregnancy. Hybrid teratomas, however, were obtained after the induction of active or passive immunological enhancement. These hybrid teratomas, although smaller than the syngeneic, contained tissues derived from the three germ layers.

Animals↗
PubMedDate not supplied

Expression of lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) in human preeclamptic placenta: possible implications in the process of trophoblast apoptosis.

Lectin-like oxidized low-density lipoprotein receptor-1 (LOX-1) was originally identified as a receptor for oxidatively modified low-density lipoprotein. It has been reported that oxidative stress and hyperlipidemia play important roles in the etiology of preeclampsia, and that placental oxidative stress may stimulate syncytiotrophoblast apoptosis in preeclampsia. In this study, we examined the expression of LOX-1 in the human placentas of normal pregnancies and in preeclampsia using immunohistochemistry and Western blot analysis, and proposed that LOX-1 has a role in trophoblast apoptosis. To analyze apoptotic activity, the expression of the specific caspase cleavage site within cytokeratin 18 was assessed immunohistochemically using the monoclonal antibody M30 CytoDeath. Both LOX-1 and M30 immunoreactivity occurred predominantly in syncytiotrophoblasts. A significantly higher number of LOX-1 and M30-positive cells were found in preeclamptic placentas than in normal placentas. The number of M30-positive cells correlated with the apoptotic index of trophoblasts determined by TdT-mediated dUTP nick-end labeling (TUNEL). Syncytiotrophoblasts showing apoptotic activity were immunopositive to LOX-1 by double immunohistochemical fluorescence. We suggest that the functional role of syncytiotrophoblasts in placental dysfunction results from the localization and upregulation of LOX-1 in the preeclamptic placenta, possible implications in upregulation of syncytiotrophoblast apoptotic activity in preeclampsia.

Adult↗