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Biomedical subjects

A Urabe

Publications and source records attributed to A Urabe.

At least 217 records · Page 12Linked to original sources
PubMed1985

Production of erythropoietin-like activity by human renal and hepatic carcinomas in cell culture.

Two types of human cancers, a renal cell carcinoma and a hepatocellular carcinoma, were investigated in vitro; both produced a marked erythrocytosis in each patient. These tumors, when transplanted into athymic nude mice, produced a remarkable erythrocytosis in the host mice. To analyze this phenomenon, the primary cultures from these xenotransplanted tumors were performed. To obtain pure tumor cell cultures, cells derived from host nude mice were eliminated by the treatment with the antiserum raised against nude mouse cells. Epithelial cells derived from each tumor attached and grew in the cultures. The conditioned media from both tumor cells revealed high erythropoietic stimulatory activities. We have characterized these erythropoietin-like activities by size-exclusion high-performance liquid chromatography. Three peaks of erythropoietin-like activities were noted after bovine serum albumin region. The molecular weights were estimated at about 55,000, 40,000, and 33,000, respectively. The results suggested that the human renal cell and hepatocellular carcinomas produced erythropoietin-like activities in vitro in culture and that erythrocytosis found in patients with cancer and in nude mice transplanted with the tumors was attributable to production of the erythropoietin-like activities by the tumor cells themselves.

Aged↗
PubMed1985

Introduction of macromolecules into hemopoietic stem cells with an erythrocyte-ghost-mediated system.

We have developed a method of introduction of macromolecules into normal human hemopoietic stem cells. The erythrocyte ghosts were loaded with diphtheria toxin fragment A (molecular weight = 22,000 daltons), which exerts cytotoxicity only in the intracellular space. Granulocyte-macrophage colonies of human bone marrow cells incubated with the above ghosts in the presence of Sendai virus decreased in number to about 10% of the control. This means that the cell fusion and the subsequent introduction of the fragment A into granulocyte-macrophage progenitors occurred at a high incidence (about 90%). This method will be useful to study intracellular events during the proliferation and differentiation of hemopoietic stem cells.

Cell Fusion↗
PubMed1985

Activation of the c-K-ras oncogene in a human pancreas carcinoma.

The human pancreas carcinoma cell line T3M-4 contains activated c-Kirsten (K)-ras oncogene detectable by the DNA-mediated gene transfer technique using NIH/3T3 cells. DNA fragments containing coding lesions have been cloned, and nucleotide sequence analysis suggests that the T3M-4 oncogene has been activated by a single nucleotide transition from A to C in the second exon, which results in the substitution of histidine for glutamine in coden 61 of the predicted amino acid sequence. The quantity analysis of c-K-ras oncogene in the DNA and RNA of T3M-4 cells revealed that the c-K-ras gene was amplified and overexpressed in T3M-4 cells. These findings indicate that the T3M-4 c-K-ras oncogene is activated by different mutational events.

Amino Acid Sequence↗
PubMed1985

Induction of proliferation of human circulating monocytes in vitro by lectin-induced factor(s) from lymphocytes.

Human peripheral blood monocytes, which have been considered to be non-dividing cells, were induced to proliferate in vitro by soluble mediator(s) from lectin-activated human lymphocytes. The lectin-induced factor from lymphocytes increased both the number of nuclei of cultured monocytes and [3H]-thymidine incorporation into the monocytes. The molecular weights of the soluble factor(s) that promote growth of monocytes were in the range of 20,000-70,000 daltons with two peaks.

Adult↗
PubMed1985

A platelet factor that stimulates the proliferation of vascular endothelial cells.

The effects of platelet factors on the growth of cultured porcine aortic endothelial cells were studied. Human platelet lysate stimulated the incorporation of [3H] thymidine into DNA. Gel chromatography on Sephadex G-75 revealed at least two peaks of activity on endothelial cells, the major peak being at an apparent molecular weight of 20,000. This activity was heat-labile and trypsin-sensitive, and did not stimulate the growth of fibro-blasts.

Animals↗
PubMed1985

Effects of recombinant interferons on the clonogenic growth of leukemic cells and normal hemopoietic progenitors.

We have examined the effects of recombinant immune and leukocyte interferons (rIFN-gamma and rIFN-alpha) on the clonogenic growth of leukemic cells and normal hemopoietic progenitors using in vitro colony assays. Both interferons suppressed the colony formation by granulocyte-macrophage progenitors (CFU-gm) and erythroid progenitors (CFU-e and BFU-e) in a dose-dependent manner. Six myeloid leukemic cell lines were less sensitive to rIFN-gamma than CFU-gm. The colony formation of some myeloid leukemic cell lines was suppressed more potently by rIFN-alpha than by CFU-gm. Four lymphoid leukemic cell lines of the T-cell type were very resistant to both recombinant interferons. Reduced sensitivity of leukemic cells to rIFN-gamma, a possible hemopoietic regulator, may explain partially the unregulated proliferation of leukemic cells in vivo.

Cell Division↗
PubMed1985

Effects of dolichol and dolichyl phosphate on in vitro differentiation of hematopoietic progenitors.

The exogenous addition of dolichyl phosphate (Dol-P), an active form of dolichol (Dol) that carries oligosaccharide chains for protein-N-glycosylation, significantly enhanced colony formation of mouse bone marrow hematopoietic progenitors (CFU-e, BFU-e, and CFU-gm) was stimulated by erythropoietin (Epo) and colony-stimulating factor (CSF), but Dol enhanced colony formation of CFU-e only. The effects of Dol or Dol-P on these hematopoietic progenitors were fully dependent on stimulation by Epo or CSF. Other mevalonate-metabolites, such as cholesterol, coenzyme Q10, and isopentenyladenine, had no effect on hematopoietic progenitors. These studies suggest that exogenous Dol-P enhances the frequency of differentiation of hematopoietic progenitors stimulated by Epo or CSF, and there may be a diversity in cellular response of these progenitors to Dol.

Adenine↗
PubMed1985

A platelet factor stimulating the proliferation of vascular endothelial cells. Partial purification and characterization.

Platelets have been shown to contain a novel growth factor that stimulates the proliferation of vascular endothelial cells in vitro. The factor potently stimulated both DNA synthesis and proliferation rate in serum-deprived endothelial cells. Gel exclusion chromatography showed at least two peaks of activity on endothelial cells, the major peak being at an apparent molecular weight of 20 000. Isoelectric focusing revealed that the pI of the factor was 4.0-4.8. It was adsorbed to a column of DEAE ion exchange chromatography and eluted with a salt gradient. The factor was heat-labile and trypsin-sensitive. The activity was not destroyed by a reducing agent including dithiothreitol. This factor stimulated the proliferation of vascular endothelial cells but was found to be inactive against normal rat kidney fibroblasts.

Animals↗
PubMed1985

Elimination of small cell lung cancer cells in vitro from human bone marrow by a monoclonal antibody.

We report here a useful method for elimination of small cell lung cancer cells in vitro from bone marrow. A monoclonal antibody, TFS-2, which mediates complement lysis and recognizes an antigen present on small cell lung cancer cells but not lymphoid cells or bone marrow cells, was used to clear infiltrated bone marrow. The antibody in the presence of complement effectively killed tumor cells, but it was not cytotoxic to bone marrow cells. When mixed populations consisting of tumor cells and bone marrow cells were treated with antibody and complement, the tumor cells were also effectively killed, except when large numbers of bone marrow cells were present, whereas TFS-2 had no significant effect on bone marrow stem cells, as judged by colony-forming unit assays.

Animals↗
PubMed1985

Transforming genes in human leukemia cells.

High-molecular weight DNAs of fresh bone marrow cells from 32 patients with fresh leukemia were assayed for the presence of transmissible activated transforming genes by a DNA-mediated gene transfer technique using NIH/3T3 cells. DNAs of bone marrow cells from four of the 32 patients induced transformation of NIH/3T3 cells. Two of the four cases, a chronic myelogenous leukemia and an acute lymphocytic leukemia, contained activated N-ras oncogenes. Molecular cloning and nucleotide sequence analysis revealed that the lesion responsible for the transforming activity was localized to a single nucleotide transition from guanine to thymine in codon 12 of the predicted protein in each of the two cases. These observations indicate that activation of N-ras oncogenes is independent of the specific stage of cell differentiation or the leukemia phenotype. The other two transforming genes associated with an acute myelogenous leukemia and an acute lymphocytic leukemia showed homology neither with members of the ras gene family nor with the human Blym-1 gene. Thus, the NIH/3T3 transfection assay frequently detects activated N-ras oncogenes in human leukemias, while other transforming genes, distinct from the ras gene family, can be detected in some leukemias by the transfection assay.

Autoradiography↗
PubMed1985

Increased glucocorticoid receptor concentration in macrophage differentiation of myeloid leukemia cells with 12-O-tetradecanoylphorbol-13-acetate.

HL60 cells, human promyelocytic leukemia cells, can be induced to differentiate into more mature myeloid forms by dimethyl sulfoxide (DMSO) or retinoic acid (RA) and into macrophage-like cells by 12-O-tetradecanoylphorbol-13-acetate (TPA) or related compounds. Macrophage differentiation of HL60 cells by TPA treatment induced a 3- to 4-fold increase in glucocorticoid receptor concentration per cell and a 2- to 3-fold increase in glucocorticoid receptor concentration per mg of protein. The ability of TPA derivatives to increase glucocorticoid receptor concentration paralleled their ability to induce macrophage differentiation. Macrophage differentiation of other myeloid leukemia cells by TPA treatment induced a 2- to 3-fold increase in glucocorticoid receptor concentration per cell. Exposure of T-lymphoblasts or erythroleukemia cells to TPA did not affect glucocorticoid receptor concentration. Myeloid differentiation of myeloid leukemia cells by DMSO or RA induced no significant change in glucocorticoid receptor concentration. The increase in glucocorticoid receptor concentration in macrophage differentiation of myeloid leukemia cells with TPA was considered to depend, not on TPA treatment, but on the process of macrophage differentiation. Further, glucocorticoid receptor concentration can be a sensitive marker of macrophage differentiation of myeloid leukemia cells.

Cell Count↗
PubMed1985

Recombinant immune interferon inhibits leukemic cell growth by a monocyte-macrophage-mediated mechanism.

We have investigated direct and monocyte-macrophage (Mono/M phi)-mediated indirect effects of recombinant immune interferon (IFN-gamma) on the growth of established leukemic cell lines (K562, KG1, ML1, HL60, U937, and THP1). The direct antiproliferative effects of IFN-gamma on these leukemic cells were mild or negligible, when estimated by 3H-thymidine incorporation. Indirect effects were assessed by the growth pattern of leukemic cells cocultured with Mono/M phi that were pretreated with INF-gamma. While the leukemic cell growth was slightly suppressed by untreated Mono/M phi, this suppression was significantly augmented by the treatment of Mono/M phi with IFN-gamma (10-10,000 U/ml). In addition, the indirect effects of IFN-gamma on leukemic cell growth were examined at different stages of maturation of Mono/M phi. The augmentation of cytotoxicity was detected only when mature Mono/M phi were treated with INF-gamma. This suggests that IFN-gamma acts on tissue macrophages and augments their cytotoxicity against leukemic cells.

Cell Division↗
PubMed1985

T-cell receptor gene rearrangement in a patient with common acute lymphocytic leukemia.

Using a beta-chain cDNA probe of the T-cell receptor, we detected T-cell receptor gene rearrangement in leukemic cells from an adult patient with common acute lymphocytic leukemia (cALL). The leukemic cells expressed non-T, non-B cell marker profiles (CALLA+, J5+, Leu-1-, Leu-4-, Ia+, B1-, c-Ig mu- and TdT+). This is the first reported case of cALL with T-cell receptor gene rearrangement and/or deletion.

Adult↗