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Biomedical subjects

C Croce

Publications and source records attributed to C Croce.

At least 37 records · Page 2Linked to original sources
PubMed1990

BCL2-mediated tumorigenicity of a human T-lymphoid cell line: synergy with MYC and inhibition by BCL2 antisense.

A gene-transfer approach was used to explore the function of the BCL2 (B-cell lymphoma/leukemia 2) gene in a human T-cell line, Jurkat. Though stable introduction of a BCL2 expression plasmid into Jurkat T cells was by itself insufficient, the combined transfer of BCL2 and MYC genes markedly enhanced the tumorigenicity of these cells in athymic mice. Moreover, a BCL2 antisense expression plasmid ablated tumor formation by Jurkat cells, providing further evidence that this oncogene contributes to the regulation of the in vivo growth of these human T lymphocytes. In addition to their influence on tumor formation, BCL2 sense and antisense expression plasmids increased and decreased, respectively, the in vitro survival of Jurkat T cells in serum-free medium. These observations extend to T cells the finding of synergy of BCL2 with MYC previously reported for B cells and provide evidence that BCL2 can regulate the growth of human T cells.

Animals↗
PubMed1990

Cloning of three human tyrosine phosphatases reveals a multigene family of receptor-linked protein-tyrosine-phosphatases expressed in brain.

A human brainstem cDNA library in bacteriophage lambda gt11 was screened under conditions of reduced hybridization stringency with a leukocyte common antigen (LCA) probe that spanned both conserved cytoplasmic domains. cDNA encoding a receptor-linked protein-tyrosine-phosphatase (protein-tyrosine-phosphate phosphohydrolase, EC 3.1.3.48), RPTPase alpha, has been cloned and sequenced. Human RPTPase alpha consists of 802 amino acids. The extracellular domain of 150 residues includes a hydrophobic signal peptide and eight potential N-glycosylation sites. This is followed by a transmembrane region and two tandemly repeated conserved domains characteristic of all RPTPases identified thus far. The gene for RPTPase alpha has been localized to human chromosome region 20pter-20q12 by analysis of its segregation pattern in rodent-human somatic cell hybrids. Northern blot analysis revealed the presence of two major transcripts of 4.3 and 6.3 kilobases. In addition to RPTPase alpha, two other RPTPases (beta and gamma), identified in the same screen, have been partially cloned and sequenced. Analysis of sequence comparisons among LCA, the LCA-related protein LAR, and RPTPases alpha, beta, and gamma reveals the existence of a multigene family encoding different RPTPases, each containing a distinct extracellular domain, a single hydrophobic transmembrane region, and two tandemly repeated conserved cytoplasmic domains.

Amino Acid Sequence↗
PubMed1990

Effect of acute or daily cocaine administration on cellular immune response and virus infection in mice.

The effects of in vivo cocaine administrations on cellular cytotoxicity were studied. Cocaine induced a dose-related immunosuppression of natural killer cell activity, with maximal depression at 1-5 mg/kg. In addition, the degree of inhibition following a single intraperitoneal (i.p.) or intravenous cocaine dose (acute treatment, 1 mg/kg) was similar to that after repeated administration (subchronic treatment: 1 mg/kg/day i.p. for 7 consecutive days or subcutaneous administration by Alzet 2001 osmotic minipumps). T cells from cocaine-treated mice failed to generate cytotoxic T lymphocytes (CTL) in mixed lymphocyte cultures and acute or subchronic cocaine treatment also inhibited CTL generation in vivo. On the other hand, acute administration induced a very rapid (24-hour) inhibition of natural cytotoxicity, with a return to normal within 72 h after treatment. By contrast, repeated doses led to more protracted immunologic consequences and a delayed recovery (144 h). The effect of cocaine on susceptibility to influenza virus (PR8) infection was also investigated. Both acute and subchronic treatment significantly decreased resistance to PR8 infection. The results clearly indicate that cocaine has a potent suppressive effect on cellular immunity and that abuse can adversely affect the outcome of infectious diseases.

Animals↗
PubMed1989

Chromosomal localization of the human osteocalcin gene.

The human osteocalcin gene was assigned to chromosome 1 by Southern blot analysis of DNAs from a panel of mouse-human somatic cell hybrids with limited numbers of human chromosomes and the complete complement of murine chromosomes. By Southern blot analysis of DNAs from mouse-human hybrids that retain specific segments of human chromosome 1, we have determined that the locus of the human osteocalcin gene is on the long arm of chromosome 1, distal (telomeric) to the -spectrin gene. Osteocalcin is a bone specific protein and it is note worthy that another osteoblast product, the bone/liver/placental alkaline phosphatase gene has also been mapped to chromosome 1.

Animals↗
PubMed1989

Deregulated BCL2 expression enhances growth of a human B cell line.

The BCL2 (B cell lymphoma/leukemia -2) and C-MYC oncogenes become activated by chromosomal translocations involving the immunoglobulin heavy chain locus in human follicular lymphomas and Burkitt lymphomas, respectively. Though much is known about the biological actions of C-MYC, little information is available concerning the functions of BCL2, particularly in human B cells. Using a gene transfer approach we contrasted the effects of deregulated BCL2 and C-MYC expression in a human EBV-immortalized B cell line GM607B. Both BCL2 and C-MYC enhanced the ability of GM607B cells to grow in reduced serum and in limiting dilution cultures. These findings provide direct evidence that BCL2 can alter the growth characteristics of human B lymphocytes, thus strengthening arguments for its role in the pathogenesis of human lymphomas.

B-Lymphocytes↗
PubMed1988

Influence of interferon-alpha on the expression of cellular oncogenes in primary chronic lymphocytic leukemia cells.

The influence of interferon-alpha 2 (IFN-alpha 2) on the mRNA levels of cellular proto-oncogenes was studied in malignant cells from patients with chronic lymphocytic leukemia (CLL). These cells can be induced to blast transform, differentiate and, in some cases, proliferate upon exposure to IFN. Treatment with IFN-alpha enhanced the levels of c-myc mRNA in malignant cells from the patients, whereas the levels of c-myb mRNA decreased, as measured by slot blot hybridizations. In cells from some patients, an enhanced expression of c-fos and k-ras was observed following exposure to IFN-alpha. No major effect on the expression of c-raf or of enolase was observed in any of the patients following exposure to IFN-alpha, whereas the levels of beta 2-microglobulin mRNA increased. In contrast to the observed effects on oncogene expression in CLL cells, IFN had no major effect on the expression of any of the tested oncogenes in lymphocytes from healthy donors or in B-cells from three neoplastic cell lines (380, FL18, RS). We conclude that IFN-alpha can enhance or repress the expression of several oncogenes in nondividing primary malignant cells from patients with leukemia. We also show that the response of malignant cells from patients to IFN-alpha is different than that seen with neoplastic cell lines which represent a similar stage of B-cell differentiation.

B-Lymphocytes↗
PubMed1987

Methadone vs morphine: comparison of their effect on phagocytic functions.

A comparison of the effects of methadone and morphine on phagocytic physiology was carried out in mice, using a number of tests, to estimate the risk of using methadone in maintenance protocols for opiates addicts. Results indicate that methadone, like morphine, reduces (a) R.E.S. activity and (b) PMN superoxide anion production, while unlike morphine it (a) does not produce haematologic changes, (b) does not exacerbate C. albicans infections, (c) does not inhibit phagocytosis and killing by murine polymorphonuclear leukocytes and macrophages, or by rabbit alveolar macrophages, and (d) does not reduce spleen and liver weight. These results are in strict agreement with those previously found in human subjects receiving controlled administration of morphine or methadone. Compared to morphine methadone therefore appears to have a lower toxic potentiality.

Animals↗
PubMed1986

Chromosomal locations of members of a family of novel endogenous human retroviral genomes.

Human cellular DNA contains two distinguishable families of retroviral related sequences. One family shares extensive nucleotide sequence homology with infectious mammalian type C retroviral genomes (T. I. Bonner, C. O'Connell, and M. Cohen, Proc. Natl. Acad. Sci. USA 79:4709-4713, 1982; M. A. Martin, T. Bryan, S. Rasheed, and A. S. Khan, Proc. Natl. Acad. Sci. USA 78:4892-4896, 1981). The other family contains major regions of homology with the pol genes of infectious type A and B and avian type C and D retroviral genomes (R. Callahan, W. Drohan, S. Tronick, and J. Schlom, Proc. Natl. Acad. Sci. USA 79:5503-5507, 1982; I. M. Chiu, R. Callahan, S. R. Tronick, J. Schlom, and S. A. Aaronson, Science 223:364-370, 1984). Analysis of the human recombinant clone HLM-2 has shown that the pol gene in the latter family is located within an endogenous proviral genome (R. Callahan, I. M. Chiu, J. F. H. Wong, S. R. Tronick, B. A. Roe, S. A. Aaronson, and J. Schlom, Science 228:1208-1211, 1985). We show that the proviral genome in HLM-2 and the related recombinant clone HLM-25 are located, respectively, on human chromosomes 1 and 5. Other related proviral genomes are located on chromosomes 7, 8, 11, 14, and 17.

Animals↗
PubMed1985

Gene for the human T cell differentiation antigen Leu-2/T8 is closely linked to the kappa light chain locus on chromosome 2.

We have mapped the gene encoding the T cell differentiation antigen Leu-2/T8 to human chromosome 2 by hybridization of a Leu-2/T8 complementary DNA clone to DNA from a panel of mouse-human cell hybrids. In situ hybridization further localizes the gene to the 2p1 region in close proximity to the Ig kappa light chain gene. The Leu-2/T8 gene translocates with C kappa to chromosome 8 in a Burkitt lymphoma line carrying a t(2;8) translocation. These data support the hypothesis that Leu-2/T8 is the human homologue of the mouse Lyt-2,3 antigen.

Animals↗
PubMed1985

Morphine and methadone impact on human phagocytic physiology.

Human subjects submitted to treatment with morphine show a severe depression of phagocytosis, killing properties and superoxide production both of their polymorphonuclear leukocytes and monocytes. Polymorphonuclear leukocyte adherence, chemotaxis, random migration, myeloperoxidase content, lysozyme content and lymphocyte Rosette E formation were poorly influenced. Methadone-treated subjects show a similar effect at phagocytic level but far less evident. These results confirm those previously found in animals and reinforce the evidence of a depressive role of morphine on phagocytic physiology.

Cytotoxicity, Immunologic↗
PubMed1984

A major human histone gene cluster on the long arm of chromosome 1.

A human histone gene cluster was assigned to chromosome 1 by Southern blot analysis of DNA's from a series of mouse-human somatic cell hybrids with 32P-labeled cloned human H4 and H3 histone DNA as probes. Localization of this histone gene cluster on the long arm of chromosome 1 was confirmed by in situ hybridization of this DNA probe to metaphase chromosomes.

Animals↗
PubMed1984

The absence of a human-specific ribosomal DNA transcription factor leads to nucleolar dominance in mouse greater than human hybrid cells.

The basis for nucleolar dominance in mouse-human cell hybrids which contained all of the mouse chromosomes but an incomplete set of human chromosomes (M greater than H) was examined at the molecular level. S1 mapping data showed that these cells had the expected levels of steady-state rRNA transcribed from mouse ribosomal gene (rDNA) transcription units but undetectable levels of rRNA derived from the human rDNA transcription templates that are also present. RNA polymerase I-dependent, cell-free transcription extracts were made from three hybrid lines and were found to be capable of transcribing cloned rDNA templates of mouse but not human origin. Partially purified human factors required for rDNA transcription in vitro were added to the M greater than H extracts. One fraction with almost no RNA polymerase I activity conferred on these hybrid cell extracts the ability to transcribe a human rDNA template. These rescue experiments suggested that this required human-specific rDNA transcription factor(s) was effectively absent from the lines we examined and could account for nucleolar dominance in M greater than H hybrid cells.

Animals↗
PubMed1983

Effect of morphine on resistance to infection.

Morphine was demonstrated to exacerbate infections. Experiments were performed to evaluate variations of phagocytic physiology during morphine treatment. In mice, morphine drastically reduced reticuloendothelial system activity, phagocyte count, phagocytic index, killing properties, and superoxide anion production in polymorphonuclear leukocytes and macrophages. Similar effects on alveolar macrophage count, phagocytosis, and killing were found in rabbits, a result which suggested a lack of species specificity. Additional experiments demonstrated that morphine (1) induces a reduction of lymphoid organ weight, (2) impairs the ability to eradicate infections and (3) is counteracted in its depressing activity on phagocytic physiology by small amounts of Corynebacterium parvum. The results suggest that there is a close relationship between the fact that morphine exacerbates infections and the fact that morphine depresses phagocytic functions; therefore, the negative effect of morphine on phagocytosis is at least one of the reasons for its negative effect on the development of infections.

Animals↗
PubMed1982

Human mutant cell lines with altered RNA polymerase II.

A human fibrosarcoma cell line, HT-1080-6TG-9AM, resistant to alpha-amanitin at concentrations up to 10 micrograms/ml, was isolated after ethylmethanesulfonate mutagenesis and stepwise selection. The mutation is stable and dominant. RNA polymerase II purified from the mutant cells showed an altered affinity for labeled alpha-amanitin and the sensitivity of the enzyme to the fungal toxin was decreased 50- to 100-fold. This functional test demonstrated that the biochemical basis for the resistance of the cells to alpha-amanitin is due to an alteration of RNA polymerase II.

Amanitins↗
PubMed1980

Expression of H-2, laminin and SV40 T and TASA on differentiation of transformed murine teratocarcinoma cells.

Murine embryonal carcinoma cells (ECCs) do not express antigens of the major histocompatibility complex (H-2), but do express cell-surface molecules shared with early embryos. ECCs are also characterized by their insusceptibility to infection by various oncogenic viruses, and their ability to differentiate into a variety of adult cell types. Differentiation of ECCs in vitro can occur spontaneously or can be induced. On exposure to retinoic acid the ECC line F9 (ref. 13) differentiates into cells which have the characteristics of parietal endoderm. When ECCs are exposed to simian virus 40 (SV40), the SV40 tumour (T) antigen is not expressed, although the virus genome reaches the nucleus, and a primary transcript of the SV40 A gene is made. However, following exposure to retinoic acid, the differentiated cells, like most mouse somatic cells, are susceptible to SV40 abortive infection and synthesize large T and small t antigens. To monitor the molecular events associated with the expression of the SV40 A gene on differentiation, we have constructed an ECC line (F9 12-1) containing a single integrated copy of the SV40 genome. This was accomplished by introducing a recombinant plasmid consisting of pBR322 linked to the herpes simplex type 1 thymidine kinase gene and SV40 genome into a thymidine kinase-deficient F9 cell line. We report here that in F9 12-1 cells exposed to retinoic acid, synthesis of the SV40 A gene product(s), T and tumour-associated specific antigens (TASA), parallels the appearance of the normal hallmarks of differentiation in this cell line, H-2 antigens and the basement membrane protein laminin.

Animals↗
PubMed1980

Hybridomas revisited.

In the report by John C. Behrendt et al. "Aeromagnetic and radio echo ice-sounding measurements show much greater area of the Dufek Intrusion, Antarctica" (29 Aug., p. 1014), the word "expedition" should have read "exploitation" in line 13 of the first paragraph on page 1014. Also, in line 2 of the next to last paragraph on page 1016, "50 to 60 cm/sec(2)" should have read "50 to 60 (cm sec(2)) x 10(-3)."

Animals↗