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Biomedical subjects

G Klein

Publications and source records attributed to G Klein.

At least 1,171 records · Page 65Linked to original sources
PubMed1975

Genetic determinants of morphological differentiation in a lymphoma-sarcoma hybrid.

Hybrid cells, YACIR/MSWBS were produced by fusion of the cells of a methylcholanthrene induced murine sarcoma MSWBS and a virus induced murine lymphoma YACIR. The hybrid cells were maintained in vitro and syngenic mice challenged at various periods after fusion. Karyological analysis has been performed on the cell line, and on the tumours which arose in vivo. The tumours were also examined histologically. Over the 2 yr following fusion there was a progressive loss of chromosomes but biarmed MSWBS derived chromosomes were selectively retained. Tumours could be divided into those whith a chromosome complement similar to that of the early line in vitro, those in which chromosome loss had occurred and those in which karyology showed a mixture of the two foregoing types. Histology showed a minority of sarcoma-like tumours reminiscent of MSWBS and the majority of these showed little chromsome loss. Most tumours showed an intermediate morphology and the great majority of these had lost moderate numbers of chromosomes. There was a very small number of lymphomatoid tumours in which chromosome loss was marked.

Animals↗
PubMed1975

Attempts to detect virus-specific DNA sequences in human tumors. III. Epstein-Barr viral DNA in non-lymphoid nasopharyngeal carcinoma cells.

Fourteen tumors of the nasopharyngeal region were analyzed for the presence of Epstein-Barr virus-specific DNA by DNA-cRNA hybridization. These data were compared to the histology of the respective tumors and the seroreactivity of the tumor-bearing patient against EBV-related antigens. With one exception, all tumor pieces containing nasopharyngeal carcinoma cells hybridized significantly with EBV-cRNA. Tumors of predominantly epithelial morphology annealed in the highest range. In situ-hybridization of freeze sections from a tumor containing almost equal amounts of tumor cells and lymphocytes revealed hybridizing DNA within nuclei of non-lymphoid cells. Although these data do not exclude the presence of EBV-DNA within lymphoid cells, they clearly demonstrate that in nasopharyngeal carcinomas the vast majority of EBV-specific DNA rests within non-lymphoid cells.

Carcinoma↗
PubMed1975

Localization and quantitation of EBV-associated nuclear antigen (EBNA) in Raji cells.

Epstein-Barr virus (EBV)-associated nuclear antigen (EBNA) was localized to chromatin fibers of Raji cells. When EBNA was labeled with the horseradish-peroxidase technique of Sternberger a strong reaction covered most fiber surfaces as observed by electron microscopy. The dry mass of Raji chromatin increased after exposure to both EBV-positive and -negative serum, but the increase was significantly larger in the material treated with positive serum.

Antigens, Viral↗
PubMed1975

Comparison between growth characteristics of an Epstein--Barr virus (EBV)-genome-negative lymphoma line and its EBV-converted subline in vitro.

The GC-BJAB cell line, which carries the Epstein--Barr virus (EBV), was derived from an EBV-genome-negative lymphoma line (BJAB) by EBV infection in vitro [G. B. Clements, G. Klein, and S. Povey (1975) Int. J. Cancer, in press]. Both lines grow at a similar rate at 37 degrees but they differ at other temperatures. BJAB grows well at 34 degrees, 37 degrees, and 39 degrees. GC-BJAB grows at 37 degrees and 39 degrees, but grows poorly at 34 degrees. At 37 degrees, GC-BJAB cultures can be maintained at the viable state for a long time after having reached saturation density (approximately 10(6) cells per ml). In contrast, BJAB cultures die very soon after having attained similar maximum density. Since the identity of the two cell lines has been critically established [Clements et al.; E. Svedmyr and M. Jondal (1975) Proc. Nat. Acad. Sci USA 72, 1622--1626; G. Klein, to be published; J. Zeuthen, personal communication] the remarkable differences in their growth properties must be attributed to the EBV genome.

Burkitt Lymphoma↗
PubMed1975

Induction of Epstein-Barr virus-associated nuclear antigen during in vitro transformation of human lymphoid cells.

Human lymphoid cells isolated from the peripheral blood of adults, from cord blood, and from fetal liver, spleen, bone marrow, and thymus were cultivated with or without a cell-free preparation of Epstein-Barr virus (EBV) with demonstrated transforming activity. The cultures were examined for the EBV-associated nuclear antigen (EBNA) and for transfromation into permanent lymphoblastoid cell lines (LCL). EBNA, seen only in cultures that had received exogenous EBV, was detected between days 1 and 6 after addition of EBV, most frequently on day 3. EBNA-positive cells had a lymphoblastoid appearance. Transformation into established LCL became apparent between days 12 and 19. The addition of pokeweed mitogen to cultures containing EBV enhanced the development of EBNA, whereas phytohemagglutinin or concanavalin A had no such effect. Neither EBNA nor transfomration was observed in lymphoid cells from fetal thymus. In fetal spleen, bone marrow, and liver cells, EBV regularly induced EBNA and LCL transformation.

Antigens, Viral↗
PubMed1975

Dynamic alterations in some surface properties of freshly explanted Moloney lymphoma cells.

When Moloney lymphoma (YAC) cells were freshly explanted from the tumor-bearing host into culture, two events occurred in the first 120 minutes: The cells lost their natural IgG coat, and their sensitivity to complement-dependent lysis (CdL) mediated by antibodies to Moloney lymphoma cells decreased or increased. An increasing sensitivity to CdL as a function of incubation time at 37 degrees C was likely to occur when the sensitivity to CdL was low at explantation. A decreasing sensitivity to CdL was probable in instances of a high sensitivity to CdL at explantation. Artifical coating of YAC cells with antibodies to Moloney lymphoma immediately after explantation moderated the alterations in their sensitivity to CdL. This occurred even though a functional antibody did not remain on the cells as evidenced from the gradual decreased sensitivity of these artifically coated cells to the addition of complement. Spent culture media in which freshly explanted cells grew for 60 or 120 minutes sometimes blocked CdL of YAC cells mediated by antibodies to Moloney lymphoma.

Animals↗
PubMed1975

An EBV-genome-negative cell line established from an American Burkitt lymphoma; receptor characteristics. EBV infectibility and permanent conversion into EBV-positive sublines by in vitro infection.

An in vitro line was derived from an American Burkitt lymphoma, designated Ra No. 1, which produced malignant tumors when inoculated into thymus-deficient nude mice. The cells have B-lymphocyte characteristics, with surface-associated mu and kappa chains and Epstein-Barr virus (EBV) receptors, and can be readily infected with EBV in vitro. B95-8 virus induced EBV-determined nuclear antigen (EBNA) but not early antigen (EA) in Ra No. 1 cells, whereas P3HR-1 virus induced both EBNA and EA, but the EA level was much lower than in the prototype Raji strain, EBNA and EA levels were comparable in Ra No. 1 and in the previously established, EBV-infection-sensitive BJA-B lymphoma. The two lines differed, however, because BJA-B could be converted into a permanent EBV-carrying line by the B95-8 but not by the P3HR-1 virus strain, whereas Ra No. 1 could be converted by the P3HR-1 virus. This demonstrates that different B-lymphocyte-derived lymphoma lines can vary with regard to the restrictive control they can exert on the same virus strain. Furthermore, virus strains vary in their sensitivity to the restrictions of the same host cell. Permanent EBV conversion of the Ra No. 1 cell did not appear to change the cellular controls, as judged by the unchanged sensitivity of the cell to viral antigen (EA, viral capsid antigen) induction by P3HR-1 virus superinfection.

Animals↗
PubMed1975

The effects of cosmic particle radiation on pocket mice aboard Apollo XVII: V. preflight studies on tolerance of pocket mice to oxygen and heat. Part II. effects on lungs.

An electron microscope examination was carried out on the lungs of 11 pocket mice (Perognathus longimembris) that breathed oxygen at 10 psi or 12 psi partial pressure over a period of 7 d, at the end of which time they were decompressed to sea-level O2 pressure, either suddenly or in 30, 60, or 90 min. Vesiculation was noted in the endothelium of the alveolarcapillary wall in most of the animals and, occasionally, blebbing. Some mitochrondria were swollen in a few of the animals. Alveolar exudate was, in general, sparse. Compared with the lungs of other rodents, the lungs of pocket mice appeared relatively resistant to the toxic effects of oxygen. This conclusion needs, however, to be tempered by the fact that 5% N2 was used in the tests reported here. Nonetheless, the results suggest that the oxygen pressures anticipated on the flight of Apollo XVII should be well tolerated by the pocket mice.

Adaptation, Physiological↗