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D L Bronson

Publications and source records attributed to D L Bronson.

At least 37 records · Page 2Linked to original sources
PubMed1982

Cell-surface antigens of a clonal human embryonal carcinoma cell line: morphological and antigenic differentiation in culture.

A cloned human embryonal carcinoma (EC) cell line has been derived from a testicular teratocarcinoma, and reproducibly forms EC tumors when injected into athymic (nu/nu) mice. These human EC cells are characterized by a newly described stage-specific embryonic antigen, SSEA-3. Unlike murine EC cells, they express major histocompatibility antigens (HLA-A, B, C and beta 2-microglobulin) but do not express the embryonic antigen SSEA-I. We also report that these cells appear to be capable of differentiation and that this can be induced by initiating cultures at low cell density. Differentiation is marked by the appearance of morphologically distinct cells and by the induction of SSEA-I, whereas the expression of other antigens, including SSEA-3, is initially diminished. This well-characterized system of human EC cells provides a model for the future investigation of other human teratocarcinoma cell lines and for the analysis of cellular differentiation during early human development.

Animals↗
PubMed1981

Induction of hepatitis B surface antigen in human hepatoma-derived cell lines.

Cultures of two human hepatoma cell lines were examined for expression of hepatitis B virus surface antigen (HBsAg). The PLC/PRF/5 cells secreted HBsAg continuously into the culture medium, whereas Mahlavu cells did not secrete the antigen. However, cytoplasmic antigen was detected in a low percentage (less than 5%) of the Mahlavu cells. The expression of HBsAg also was assayed in cultures treated wtih dexamethasone (DXM), 5-iodo-2'-deoxyuridine (IdUrd), or both. The results demonstrated that: (i) DXM stimulated secretion of HBsAg by PLC/PRF/5 cells but not by Mahlavu cells; (ii) the percentage of Mahlavu cells expressing cytoplasmic HBsAg was not increased in any cultures if the medium was replaced at 24 t0 48 h intervals but was increased approx. fivefold within 4 days in cultures treated with DXM or IdUrd/DXM if the medium was not changed. However, no increase was noted in the intensity of the immunoperoxidase stain of PLC/PRF/5 cells that expressed cytoplasmic antigen in any DXM cultures; (iii) HBsAg expression was stimulated to a lesser extent in IdUrd/DXM cultures than in DXM cultures and was not enhanced in IdUrd cultures. Thus, DXM enhanced secretion of HBsAg by PLC/PRF/5 cells within 24 h and, after a delay, enhanced expression of cytoplasmic antigen by Mahlavu cells. However, antigen secretion by Mahlavu cells evidently was blocked.

Carcinoma, Hepatocellular↗
PubMed1981

The expression of MHC antigens by human teratocarcinoma derived cell lines.

We have used flow microfluorimetry to investigate quantitatively the expression of HLA-A, B and C antigens, and beta 2 microglobulin, by cell lines derived from human teratocarcinomas, Although low levels of these cell surface molecules were expressed by all the lines examined, there was no evidence of discrete HLA-A, B, C/beta 2-microglobulin positive and negative subpopulations in any cultures. In contrast, using similar techniques, no murine embryonal carcinoma cell line was found to express the homologous H-2 antigens, It is suggested that human embryonal carcinoma cells may differ from their mouse counterparts by expressing low levels of major histocompatibility antigens

Animals↗
PubMed1981

Cytogenetic evidence for premeiotic transformation of human testicular cancers.

To determine the point at which transformation of the germ cell occurs during meiosis in nonseminomatous testicular cancer, the sex chromosome compositions of 15 cell lines derived from primary tumors or metastases of 12 patients with testicular cancer were analyzed by trypsin G-banding analysis and Y-body staining. The simultaneous existence of both X- and Y-chromosomes in a single cell has been confirmed in 14 cell lines. This suggests that transformation of the cell occurs before the first meiotic division because it is known that segregation of X- and Y-chromosomes occurs during the first meiotic division. An incidental finding was the presence of Barr bodies in some cell lines containing more than one X-chromosome, which is consistent with the known primitive nature of testicular cancer and its ability to differentiate independently from the male host.

Cell Differentiation↗
PubMed1980

A comparative study of eight cell lines derived from human testicular teratocarcinoma.

Eight independent cell lines, derived from human testicular germ-cell tumors, were examined for the expression of various markers. These included major histocompatibility and embryonic antigens, chorionic gonadotropin, alpha fetoprotein, alkaline phosphatase, plasminogen activator, and infectivity by SV40. No line consisted primarily of choriocarcinoma or yolk sac cells, but several contained cells resembling murine embryonal carcinoma; some of these lines formed tumors with the distinctive features of embryonal carcinoma when injected into immunosuppressed animals. It is proposed that human embryonal carcinoma cells, unlike those of the mouse, correspond to a preblastocyst stage of development.

Alkaline Phosphatase↗
PubMed1980

Cell line derived from a metastasis of a human testicular germ cell tumor.

A cell line, designated 833K-E, has been established from a metastasis of a human testicular germ cell tumor that consisted of four histological types of tumor cells. The 833K-E cells have morphological and ultrastructural characteristics of epithelial cells and a hyperdiploid karyotype indicative of their human male origin. The cells grow in agar cultures and produce in nude mice tumors which have the hstological features of embryonal carcinoma without differentiated elements. Many of the cells express a stage-specific mouse embryonic antigen, and low levels of the major histocompatibility antigens and beta 2-microglobulin also were detected on a large percentage of the cells. A lymphoblastoid cell line (833K-LC) established from the same tumor specimen expresses major histocompatibility antigens and beta 2-microglobulin but does not express the embryonic antigen.

Animals↗
PubMed1980

Nonrandom abnormalities in chromosome 1 in human testicular cancers.

Trypsin G banding was performed on metaphase chromosomes from 14 cell lines derived from primary tumors or metastases of 11 patients with testicular cancer. Most of the cell lines, 11 of 14, have a modal number between 51 and 61. All lines have numerical and structural changes involving chromosome 1 with trisomy of the q arm being the common aberration. Break points in chromosome 1 were nonrandom, being concentrated in the regions of p12, q12, p36, and p22, which resulted in morphologically identical marker chromosomes in different cases. These changes probably are not artifacts of cell culture. In one instance, three lines derived from the same patient, one from tissue removed at operation, and two from separate metastases removed at autopsy nearly 3 years later after unsuccessful radiotherapy and chemotherapy had identical chromosome compositions. In another case, lines derived from a primary tumor and a metastasis from the same patient also had identical marker chromosomes. The consistent involvement of chromosome 1 in aberrations may be associated with the highly malignant nature of testicular cancers.

Adult↗
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↗