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Biomedical subjects

D L Bronson

Publications and source records attributed to D L Bronson.

15 recordsLinked to original sources
PubMed1991

Plasma protein and apolipoprotein synthesis by human yolk sac carcinoma cells in vitro.

Three human yolk sac carcinoma cell lines were characterized for the expression of several markers. Each of the cell lines expressed alpha-fetoprotein, without detectable levels of chorionic gonadotropin, and the level of alpha-fetoprotein expression increased dramatically when the cultures were held without passage for extended periods. The secretion of a number of plasma proteins was documented by metabolic labeling, immunoprecipitation, and gel analysis. The major plasma proteins detected were alpha-1-antitrypsin, alpha-fetoprotein, transthyretin, beta-2 microglobulin, and plasminogen, with lower levels of transferrin and complement C4 released. Apolipoproteins B, E, and A1 were secreted in high levels as well and were found in the form of lipoprotein particles. Time course experiments on the synthesis of apolipoproteins E and A1 indicated that, as with alpha-fetoprotein, the level of synthesis increased substantially when the cultures were held without passage. The results indicate that these yolk sac carcinoma cells display a protein expression profile similar to that observed for the human yolk sac, and the possibility that the cells may have the potential to differentiate is discussed.

Apolipoproteins↗
PubMed1979

Induction of retrovirus particles in human testicular tumor (Tera-1) cell cultures: an electron microscopic study.

The Tera-1 and Tera-2 cell lines, established from germ-cell tumors of the human testis, were examined by electron microscopy for particles with the morphology of retroviruses. Extracellular and budding particles were observed at low frequencies only in cultures of Tera-1 cells that had been treated with 5-iodo-2'-deoxyuridine and dexamethasone. No particles were detected in untreated cultures of Tera-1 cells or in any preparations of Tera-2 cells.

Cell Line↗
PubMed1979

Carcinoembryonic antigen-like substance derived from human prostate.

Carcinoembryonic antigen-like substance, previously detected in large amounts in the medium from cultures of human prostatic epithelial cells, also is present in extracts of benign and malignant human prostate. By column chromatography, the prostate-derived carcinoembryonic antigen-like substance derived from cultured prostate is the same as that in tissue extracts and is distinctly different from colon-derived carcinoembryonic antigen. The molecular weight of prostate-derived carcinoembryonic antigen-like substance is estimated to be greater than 5 x 10(5). Prostate-derived carcinoembryonic antigen-like substance may be a prostate-specific substance.

Adenocarcinoma↗
PubMed1978

Biochemical markers of cultured human prostatic epithelium.

Medium from primary cultures of human prostatic cells was examined for polyamines and carcinoembryonic antigen. Spermine was elevated in medium from 5 of 17 epithelial cell cultures but was not found to be a specific marker for cultured human prostatic epithelial cells. Carcinoembryonic antigen was elevated in all 27 prostate epithelial-cell culture fluids tested, 24 of which had more than 20 ng. carcinoembryonic antigen per milliliter. Medium from other cultured human cells (prostate fibroblasts, genitourinary tumor and non-tumor cells), as well as control medium, contained less than 1 ng. carcinoembryonic antigen per milliliter. Carcinoembryonic antigen, as measured in this study, is a way to demonstrate the presence of human prostatic epithelial cells in culture.

Autoanalysis↗
PubMed1978

Morphologic evidence for retrovirus production by epithelial cells derived from a human testicular tumor metastasis.

Ultrastructural examination of primary and subcultured epithelial cells established in vitro from an abdominal metastasis of a human testicular tumor revealed particles with the morphology of retroviruses. These structures, found only after extensive scanning of the cells, were observed budding from microvilli and from the outer cell membrane and as extracellular particles. Production of these virus particles was stimulated by the incubation of cells in culture medium containing 5-iodo-2'-deoxyuridine and dexamethasone.

Abdominal Neoplasms↗
PubMed1978

Transitional cell cancer: establishment and characterization of cell lines.

Eleven long-term (in culture more than 1 yr) cell lines were established from surgical specimens of human TCC. Characterization studies performed on the individual cell lines showed that each 1) demonstrated an abnormal human karyotype, 2) grew in soft agar, 3) exhibited rapid growth and multilayering 4) was free from microbial and HeLa cell contamination, 5) produced tumors in cheek pouches of immunosuppressed Syrian golden hamsters, 6) contained ultrastructural features consistently found in epithelial cells in culture, and 7) could be grown to high cell densities in roller-bottle cultures.

Animals↗
PubMed1977

Production of carcinoembryonic antigen by human prostate epithelial cells in vitro.

The medium from all 16 human prostate epithelial cell cultures tested contained elevated levels of carcinoembryonic antigen (CEA) or CEA-like substance; 11 of 16 had greater than 20 ng CEA/ml. In contrast, medium from cultures of other human tissues (prostate fibroblasts, genitourinary tumors, melanoma, and nontumor tissue), as well as media controls, contained less than 1 ng CEA/ml. Results indicated that CEA determination may provide a way to identify human prostatic epithelium in culture.

Carcinoembryonic Antigen↗
PubMed1977

Properties of cell lines established from transitional cell cancers of the human urinary tract.

Characterization studies have been carried out on eight cell lines (253J, 192B, 639V, 647V, 486P, 575A,743E, and 751G) established from transitional cell cancers of the human urinary tract. Although subtle morphological differences exist among individual lines, each has an epithelial morphology and exhibits multilayering. The doubling times for the cells range from 20 to 56 hr, and at least a 1-to-3 split can be achieved when they are subcultured every 4th day. Karyotypic analysis revealed a hyperdiploid stemline for each cell line, and presence of a Y chromosome was confirmed by Q banding in five of the lines. The tumorigenic nature of the cell lines was demonstrated by their production of tumors in hamsters and confirmed by colony formation in agar. The transitional cell cancer lines were shown to be free of Mycoplasma, and their glucose-6-phosphate dehydrogenase mobility patterns and their Karyotypes prove that they are not HeLa cells.

Animals↗
PubMed1976

A comparison of four methods used to concentrate Rous sarcoma virus from tissue culture fluids.

Three methods of pelleting, pelleting followed by Pronase treatment, polyethylene glycol (PEG)-Pronase, and diaflo ultrafiltration (diafiltration) were used to concentrate RSV(RAV-1) from tissue culture fluids. Sucrose-gradient fractions containing virus preparations which had been concentrated by diafiltration or pelleting were heavily contaminated with amorphous debris. This debris was not present in similar, gradient-purified preparations that had been concentrated by the PEG-Pronase or pellet-Pronase methods. Maximum recovery of radiolabelled virus particles and virion-associated RNA-dependent DNA polymerase activity was obtained in gradient fractions containing virus concentrates prepared by the pellet-Pronase and PEG-Pronase methods. Although there were slight differences in recovery by these two methods, the advantages of the PEG-Pronase method make it the preferred method, especially when large volumes of tissue culture fluids are used.

Avian Sarcoma Viruses↗
PubMed1976

Biochemical characteristics of rat C-type virus WF-1.

The non-oncogenic rat C-type virus WF-1, isolated from a Wistar-Furth rat embryo cell line, was characterized biochemically. The purified virus has a buoyant density of 1.15 to 1.16 g/cm3 in sucrose, RNA-dependent DNA polymerase (reverse transcriptase) activity, and RNA with a sedimentation coefficient of 62 to 68 S. The viral RNA is single-stranded, and, upon treatment with heat, yields components with sedimentation coefficients of 36 S, 18 to 20 S, and 4 to 12 S.

Animals↗
PubMed1976

In vitro cultivation of epithelial cells derived from tumors of the human urinary tract.

Finely minced explants from 54 TCC2 of the human urinary tract were cultured in vitro in an attempt to establish cell lines. Cells with epithelial morphology grew out from 48 tumor explants, and long-term cell cultures were established from 10. Six of the cell cultures have been maintained for over 18 months with 50 to 70 transfers and, therefore, are considered permanent cell lines. The epithelial cells in the established cultures are small, exhibit rapid doubling time, and show multilayering. The cells were examined both microscopically and by cultivation techniques, and they were found to be free from contaminating microorganisms, including Mycoplasma. The established cultures grow rapidly in roller bottles and, therefore, can be produced in large quantities. These cells also remain viable after being stored for 3 years in liquid nitrogen.

Carcinoma, Transitional Cell↗
PubMed1975

Concentration of Rous sarcoma virus from tissue culture fluids with polyethylene glycol.

Concentration of Rous sarcoma virus from tissue culture fluids with polyethylene glycol, with and without NaCl or dextran sulfate, resulted in significant and highly variable losses caused by entrapment of virus particles in proteinaceous debris. Treatment of concentrated preparations with Pronase greatly enhanced the recovery of virions. Maximum recovery of virus particles was obtained by the addition of 8% polyethylene glycol and 0.4 M NaCl to tissue culture fluids, followed by Pronase treatment of the concentrated virus preparations.

Animals↗