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Biomedical subjects

S Sell

Publications and source records attributed to S Sell.

At least 199 records · Page 11Linked to original sources
PubMed1978

Hepatocyte growth control: in vitro approach to problems of liver regeneration and function.

Primary monolayer fetal and adult rat hepatocyte culture systems, which are being used to help analyze in vivo mechanisms controlling liver regeneration, proliferation, and differentiation are described. With results from animal studies of normal or genetically altered rats subjected to partial hepatectomy, to chemical infusions, or to specific dietary deficiency regimens, an apparently complex growth regulatory pattern has emerged. The data suggest a working hypothesis postulating interactions among hormone, nutritional, lipoprotein, and novel nucleotide factors at multiple regulatory sites. These findings may provide some conceptual and experimental basis for future research regarding the development of hepatic cancer, as it may arise spontaneously or from exposure to environmental carcinogens.

Animals↗
PubMed1978

Immunopathology.

Explore the source record for details and available documents.

Anaphylaxis↗
PubMed1978

Enhancement of DL-ethionine-induced liver carcinogenesis in rats fed a choline-devoid diet.

The effects of a choline-devoid (CD) or a choline-supplemented (CS) diet on the induction of liver tumors in rats by DL-ethionine were investigated. Groups of male outbred Sprague-Dawley rats were fed a plain CD or a plain CS diet, or the same diets containing 0.05% DL-ethionine. Hepatocellular carcinomas developed in 50% of the rats fed the CD+ethionine diet for 14 weeks and in about 80% of the rats fed the same diet for 22-30 weeks. No hepatocellular carcinomas developed in rats fed the CS+ethionine diet, the plain CD diet, or the plain CS diet up to 30 weeks. The findings suggest that a CD diet alters the response of rat liver to DL-ethionine and leads to an early and enhanced induction of hepatocellular carcinoma.

Animals↗
PubMed1978

Transfer of specific immunity with RNA.

The term "immune RNA" (iRNA), as presently used, refers not to a characterized species of RNA but to phenol extracts of lymphocytes from immunized animals, which have the capacity to transfer a variety of immune products or activities. These include synthesis of specific antibody, development of specific cellular (delayed) hypersensitivity, and production of immunoglobulin allotypic or idiotypic specificities. Recent evidence that iRNA might be used as a specific therapeutic agent to induce immunity to tumors has stimulated an increased interest in this area of research. The purpose of this article is to review the current status of studies on iRNA.

Animals↗
PubMed1978

Early histological and functional alterations of ethionine liver carcinogenesis in rats fed a choline-deficient diet.

The effects of feeding a choline-deficient (CD) or a choline-supplemented diet upon the early stages of DL-ethionine carcinogenesis in rat liver were investigated. Low levels of DL-ethionine (0.05 and 0.10%) when fed with a CD diet were found to induce within 4 weeks a massive proliferation of oval cells without significant cell necrosis or presence of inflammatory cell infiltrates. The same levels of ethionine when fed with a choline-supplemented diet caused no significant histological alteration of the liver. In rats fed the CD plus ethionine diets concomitant with the proliferation of oval cells, there was a marked elevation in the content of alpha1-fetoprotein in both liver and plasma. After specific immunofluorescence staining, oval cells stained intensely for albumin and alpha1-fetoprotein. Hepatocytes stained only for albumin, and bile duct cells stained for neither albumin nor alpha1-fetoprotein. These results indicate that a diet deficient in choline markedly alters the response of rat liver to carcinogenetic doses of ethionine. Thus, ethionine hepatocarcinogenesis in rats fed a CD diet may be a useful model for the exploration of the mechanism(s) whereby a dietary factor influences hepatocarcinogenesis.

Alanine Transaminase↗
PubMed1978

Distribution of alpha-fetoprotein- and albumin-containing cells in the livers of Fischer rats fed four cycles of N-2-fluorenylacetamide.

Immunofluorescent localization of alpha-fetoprotein (AFP)- and albumin-containing cells was determined in the livers of Fischer rats fed 0.05% N-2-acetylfluorenamide for four 2-weeks-on, 1-week-off cycles. After this exposure multiple changes in the liver include over 1000 neoplastic nodules/liver, as well as extensive production of so-called oval cells and focal zones of atypical hepatocellular hyperplasia. Approximately 1% of the oval cells contain AFP, and about half of the zones of atypical hyperplasia include cells that contain AFP, but none of the neoplastic nodules or normal hepatocytes have any AFP-containing cells. Since up to 60% of the hepatocellular carcinomas developing from this regimen will predictably produce AFP, it is tentatively concluded that hepatocellular carcinoma may arise not only from "premalignant" neoplastic nodules but also from oval cells or the atpyical differentiation of hepatocytes.

2-Acetylaminofluorene↗
PubMed1977

Origin of embryo-derived yolk sac carcinomas.

The origin of yolk sac carcinoma obtained from rat embryos transplanted to extrauterine sites was traced to the extraembryonic portion of 9-day egg-cylinders. Under appropriate conditions cells of the extraembryonic portion of the egg cylinder differentiate into cells of parietal yolk sac epithelium, continue to proliferate and form retransplantable malignant tumors. Serum concentrations of alpha-fetoprotein were elevated in rats bearing yolk sac carcinomas and in some animals bearing teratomas admixed with yolk sac carcinoma. Possible factors that regulate the survival and proliferation of yolk sac epithelium in extrauterine sites are briefly discussed.

Animals↗
PubMed1977

Surface immunolglobulin on rabbit lymphoid cells. VI. Failure to detect d and e group immunoglobulin allotypes on lymphocytes by immunoelectron microscopic labeling.

Surface immunoglobulin allotypes on rabbit peripheral blood lymphocytes (PBL) and spleen lymphocytes are detected by an immunoferritin labeling technique for electron microscopy. Human red blood cells, chemically coated with purified rabbit IgG of specific allotypes, served as test cells to assess the labeling specificity and efficiency. Immunoelectron microscopic labeling reveals that groups a, b, d and e allotypic specificities are readily detectable on passively coated test cells. However, only a and b group markers are detectable on lymphocytes. On rabbit PBL both a (VH of Fd region) and b (kappa chain constant region) group allotypes are detectable (73-78% and 68-77%, respectively); on spleen cells, 46% and 52-55% are positive for a and b locus allotypes, respectively. The d and e allotypes (i. e. gamma chain-specific) are undetectable on PBL or on spleen lymphocytes using this method. We conclude that the d and e group allotypes are either not present on the lymphocyte surface or are buried in the surface membrane and unacessible to the antisera used in this immunoferritin labeling technique.

Animals↗
PubMed1977

Yolk sac carcinoma grown from rat egg cylinders.

Eight-day rat egg cylinders transplanted in toto under the kidney capsules of adult histocompatible recipients gave rise to small nodules composed of parietal yolk sac cells surrounded by Reichert's membrane-like material. These yolk sac cells could grow and give rise to malignant, transplantable tumors identical to mouse yolk sac carcinomas derived from teratocarcinoma. The sera of rats with yolk sac tumors contained elevated concentrations of alpha1 fetoprotein.

Animals↗
PubMed1977

Serum alpha-fetoprotein in a mouse strain (C3H-Avy fB) with spontaneous hepatocellular carcinomas.

In a study of the association between circulating alpha-fetoprotein concentrations and spontaneous hepatocellular carcinomas, we examined C3H-Avy fB mice, which with age consistently demonstrate a rapidly increasing incidence of hepatic cancer. Although elevated alpha-fetoprotein levels are observed in association with the majority of these tumors, no elevation of alpha-fetoprotein was observed during the life course of non-tumor-bearing mice despite their age-dependent risk for hepatic cancer. Therefore, whatever the evolutionary or age-related biological changes may be that lead to tumor formation in this mouse, they are not linked to the synthesis of significant amounts of this oncofetal protein.

Age Factors↗
PubMed1977

Surface immunoglobulin on rabbit lymphoid cells. IV. Ultrastructural labelling of A and B group allotypic determinants.

Equal numbers of rabbit peripheral blood lymphocytes (PBLs) label for either a- or b-group immunoglobulin allotypes using a modification of the mixed antiglobulin reaction of Coombs adapted for electron microscopy. This technique which employs immunoferritin markers is consistently more sensitive than other methods used for labelling surface Ig on lymphocytes. Although approximately 75 per cent of PBLs label for either a- or b-group allotypes, the number of immunoferritin grains on the cell surface after labelling for b group allotypes is nearly twice as great as that observed after labelling for a group allotypes. We conclude that essentially all Ig-bearing blood lymphocytes of the rabbit express both heavy chains (a allotypes) and light chains (b allotypes) on their surface membranes, but that light chain allotypic determinants are more accessible or exposed than the heavy chain (Fd) allotypic determinants.

Animals↗