c-Ki-ras gene amplification and malignant behavior in murine embryonal carcinoma cell lines.

Embryonal carcinoma (EC) cells are malignant components of murine teratoma tumors. To extend our earlier findings concerning c-Ki-ras amplification in the embryonal carcinoma PCC4 cell line, we examined the c-Ki-ras protooncogene and its expression in other EC cell lines. We report here that c-Ki-ras amplification is not a general feature of EC cell lines since neither PCC3, PCC6, nor F9 cell lines have an amplified copy number of this protooncogene.

[Immunohistochemical localization of alpha-fetoprotein in the vitelline sac of a two-week old human embryo].

Histological sections of a stage 6b human embryo (13-15 days old) were immunohistochemically stained for specific alphafoetoprotein (AFP). Conspicuous AFP+ endodermal cells were observed in the yolk-sac wall using the ABC peroxidase technique, which gave consistent results on dismounted and decolorized old slides.

[Immunohistochemical localization of chorionic gonadotropin and alpha fetoprotein in polyembryomas: description and interpretation].

As polyembryomas are special forms of human teratomas in which numerous structures mimicking the early stages of the human embryo are conspicuous, immunoperoxidase staining of these embryoid bodies (EB) has been used to reveal the initial appearance and localization of beta HCG and AFP, respectively, in amnion and in primary yolk-sac. EB are involved in the building of various questionable patterns of teratomatous germ-cell tumours. Special emphasis has been placed on tracking yolk-sac tumour patterns through dislocating EB, using a specific anti-human AFP serum.

Molecular duality of DNA ligase in axolotl corresponds to distinctive transcriptional information.

Based upon the use of specific antibodies and sucrose gradient sedimentation analysis, the present work describes the use of the post-transcriptional equipment of the urodele egg to compare the information contained in two RNA samples extracted from respectively liver and activated axolotl eggs. It is shown that besides the normal DNA ligase activity present in the host Pleurodeles eggs, RNA can translate for the specific carried information revealing a difference between the two samples. Moreover, unlike in nuclear transplantation, the homologous DNA ligases are not mutually exclusive.

[Immunological localization of alpha-fetoprotein in the proximal endoderm and its significance in extra-embryonic differentiation of teratocarcinomas in the mouse].

The ABC technique using a specific anti-mouse alpha-foetoprotein (AFP) serum permits identification of groups of extraembryonic proximal endoderm cells in certain teratocarcinomas. These AFP+ cells are always associated with trophoblastic and parietal endodermal patterns and structures. These observations strongly support the hypothesis of a common precursor to the extraembryonic tissues which appears during the first phases of egg development.