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J Uriel

Publications and source records attributed to J Uriel.

140 records · Page 8Linked to original sources
PubMedDate not supplied

In vitro uptake of exogenous alpha-fetoprotein by chicken dorsal root ganglia.

Exogenous chicken alpha-Fetoprotein (AFP) was added to embryonic chick dorsal root ganglia plated on gelatin-coated tissue culture dishes at different stages during the differentiation process and its intracellular uptake demonstrated by immunocytochemical methods. Other embryonic serum proteins were added as a control. Morphologically well-differentiated neurons (ganglion cells) appeared positively labeled for AFP, contrasting with weakly stained other cell types: these included spindle-shaped cells identified as Schwann cells and larger, often closely packed cells, which could be less mature neurons. Fibroblasts were found negative or faintly stained. No AFP was noticeable in cultures grown in the absence of the protein. These results suggest that the presence of AFP in the developing CNS is for the most part, if not entirely, due to protein uptake as opposed to in situ synthesis.

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PubMedDate not supplied

Immunocytochemical quantitative study of alpha-fetoprotein in normal and neoplastic neural development.

The presence of alpha-fetoprotein (AFP) was studied in developing nervous tissues: rat cerebral cortex and neuroepithelial derivatives of a murine teratocarcinoma. AFP was localized by an indirect immunohistoperoxidase technique. Using serial dilutions of anti-AFP antibodies, the end-points of staining (minimal concentration of antibodies giving a positive labelling) were established. These points enabled the evaluation of the amount of stained AFP at different periods of development. In rat cerebral cortex, AFP showed one maximum amount on the 19th-20th day 'postcoitum' (in moderately differentiated structures), and two minima on the 13th-14th day (in primitively differentiated ones) and the 28th-29th day (in well-differentiated ones), respectively. Similarly, one maximum and two minima were established in the derivatives of teratocarcinoma imitating normal neural development.

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PubMedDate not supplied

Immunochemical characterization of sex steroid-binding protein (SBP) of human sera.

An immunodiffusion autoradiographic technique for the characterization in antigen-antibody immunoprecipitates of sex steroid-binding protein (SBP) is presented as well as procedure for the preparation of monospecific antiserum anti-human SBP. The latter consists of rabbit immunization with SBP-antibody precipitates obtained after preparative electroimmunodiffusion of human pregnancy plasma.

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PubMedDate not supplied

Lack of inhibition by mouse alpha-foetoprotein (AFP) of in vitro induced lymphocyte blastogenesis.

Mouse amniotic fluids (MAF) were tested for their inhibitory effect on the transformation of lymphocytes by concanavalin A, phytohemagglutinin or lipopolysaccharide of Escherichia coli, and on mixed lymphocyte cultures. Eight of the thirteen samples tested contained inhibitory activity equal or superior to 50 % of the controls. Pure preparations of mousealpha-foetoprotein (AFP) were obtained from these or other MAF-pools by immunoadsorption and/or by affinity chromatography on oestradiol-Sepharose. None of the isolated samples of AFP, whether originating from immunosuppressive MAF-pools or from pools lacking activity, exhibited a significant inhibitory effect on the in vitro transformation of lymphocytes. The suppressive properties of the MAF samples and the non-suppressive activity of samples of pure AFP were not affected by the addition of oestradiol-17 beta or after removal of endogenous oestrogens by exhaustive dialysis against 15 % dioxan solutions.

Amniotic Fluid↗
PubMedDate not supplied

In vitro evaluation of the differential cytotoxicity of keto-C-glycosides toward normal and malignant cells.

In a previous work, we have shown that some members of the family of keto-C-glycosides (KCGs) possess interesting biological properties as they exhibited cytotoxic effects at the nanomolar level on malignant cells. In this report, we selected six KCGs in order to investigate their selective cytotoxicity on several malignant epithelial and lymphoblastoid cells, as well as on their normal counterparts. For this purpose, we compared the activities of KCGs upon hepatoma cells and hepatocytes and upon lymphoma cells, normal lymphocytes and bone marrow cells. The tested drugs showed real discriminating cytotoxic effects since the cytotoxicity was several log greater on malignant than on non malignant cells. An in vitro comparative study of KCGs and some conventional chemotherapeutic agents showed that two of them were more potent than 5-fluorouracil, cis-platinum and etoposide. It is interesting to note that KCGs showed very low cytotoxic effects on either murine splenocytes, human peripheral blood lymphocytes or human bone marrow cells, indicating a weak immunosuppressive activity. The results presented here strongly suggest the selective cytotoxic activity of KCGs toward tumoral cells.

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