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Biomedical subjects

S Okamura

Publications and source records attributed to S Okamura.

At least 199 records · Page 11Linked to original sources
PubMed1991

A patient with primary plasma cell leukemia accompanied by an extensive polypoid infiltration of the gastrointestinal tract.

A 37-year-old male presented with primary plasma cell leukemia (PCL) with kappa-type Bence Jones proteinuria (BJP) and polyposis of the stomach and colon. His plasma cell leukemia was not preceded by a pre-existing multiple myeloma, and presented the complication of polyposis in both stomach and colon. Biopsy of mucosal lesions revealed marked accumulation of atypical plasma cells with positive cytoplasmic kappa-chain. No amyloidosis was present. His disease responded remarkably well to intermittent melphalan and prednisolone. This case represents an uncommon combination of primary plasma cell leukemia and polypoid gastrointestinal lesions with plasma cell infiltration.

Adult↗
PubMed1991

[The application of in vivo diffusion weighted magnetic resonance imaging to intracranial disorders].

We have developed a magnetic resonance (MR) spin echo method to obtain diffusion weighted imaging using motion-probing gradient (MPG) pulses in one or three orthogonal directions before and after a 180 degree pulse. Phantom models containing water and acetone, normal volunteers and patients with brain tumors, brain edema and infarction were examined. Experimental models of brain edema including triethyltin intoxication and cold injuries were also examined in Wistar rats. MRI was performed at a 1.0-T clinical machine or a 4.7-T experimental machine using spin echo pulse sequences with or without additional MPGs on one or three orthogonal axes. The one direction method was useful to define diffusion anisotropy of myelinated axonal fibers in white matter. Faster diffusion was detected in the white matter parallel to the direction of MPGs. On the other hand, slower diffusion was detected perpendicular to the direction of MPGs because the myelin sheath restricted water diffusion. The three orthogonal gradients method was useful to demonstrate the difference in the diffusion coefficients in various diseases due to its larger total gradient strength. The clear distinction between the cytotoxic edema, which revealed slower diffusion, and the vasogenic edema, which revealed faster diffusion, was demonstrated in the experimental models using diffusion weighted image. In the clinical cases, faster diffusion was demonstrated in the brain tumor and perifocal vasogenic edema, which was in agreement with the results in the experimental models of rats. Brain tumors such as low grade astrocytoma with microcysts and perifocal vasogenic edema have very wide extracellular space.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1991

[Endoscopic ultrasonography in the assessment of invasive cardiac cancer].

The aim of this study was to assess the accuracy and limitation of Endoscopic ultrasonography (EUS) in the preoperative evaluation of the cardiac cancer (cancer in the area less than 2 cm from the esophago-gastric junction). EUS was preoperatively performed in 20 patients with cardiac cancer. These cases were visualized by the water immersion method and balloon contact method. The results were correlated with the histology of resected specimens. EUS was accurate in assessing the depth of tumor infiltration. Over all accuracy of EUS for cardiac cancer was 90%. Recognition of ultrasonographic patterns had enabled us to judge the mode of tumor infiltration whether expansive or infiltrative. Microscopical spread over 5 mm to the esophagus of the cardiac cancer could be detected by EUS. EUS was accurate in diagnosing thoracic lymph nodes (No. 110, 111, 112) metastasis of the cardiac cancer (accuracy 86%). EUS was valuable in the clinical diagnosis of the cardiac cancer.

Adult↗
PubMed1990

Production of interleukin 6 from human liver cell lines: production of interleukin 6 is not concurrent with the production of alpha-fetoprotein.

The production of interleukin (IL) 6 from six human liver cell lines, including Chang liver, HLF, HLE, HepG2, PLC/PRF/5, and HuH-7, was investigated using enzyme-linked immunosorbent assay and Northern blot analysis. When cells were cultured in the presence of 12-O-tetradecanoylphorbol-13-acetate, significant amounts of IL6 were detected in the culture supernatants of Chang liver cells, HLF cells, and HLE cells. However, IL6 was not detected in the culture supernatants from HepG2 cells, PLC/PRF/5 cells, or HuH-7 cells which had been treated similarly. To further investigate the production of IL6, expression of the IL6 gene was studied. Results of Northern blot analysis using IL6 complementary DNA as a probe showed that the induction was initiated at the mRNA level. Moreover, IL6 mRNA was also induced by IL1 beta and tumor necrosis factor but not by a calcium ionophore (A23187) or IL6 itself in Chang liver cells. This is the first study to demonstrate the production of human IL6 in liver cells. Furthermore, when the production of alpha-fetoprotein (AFP) from the liver cell lines was examined, the three that were able to produce IL6 failed to produce AFP, whereas the other three cell lines succeeded in producing AFP. These observations may indicate the heterogeneous origin of the liver cell lines.

Adolescent↗
PubMed1990

Expression of the thymosin beta 4 gene during differentiation of hematopoietic cells.

Thymosin beta 4 (T beta 4) was originally isolated as a thymic hormone. Its functional properties remain obscure; however, the N-terminal peptidic sequence could have a regulatory function on hematopoietic stem cell proliferation. To investigate the mechanism of T beta 4 expression, we studied T beta 4 gene expression in various leukemic cells and in established cell lines. Among leukemic cell samples obtained from leukemia patients, the T beta 4 gene was highly expressed in a lymphoid lineage, especially in adult T-cell leukemia (ATL) cells, rather than in a granulocyte lineage. The T beta 4 gene was more transcriptionally active in chronic B-cell leukemia than in acute B-cell leukemia, while it was inactive in plasma cell leukemia. We also found that cells from one of the ATL patients transcribed a heterogeneous message. T beta 4 messenger RNA increased in MOLT-3 during differentiation by 12-O-tetradecanoylphorbol-13-acetate (TPA), in HL60 cells induced by TPA or dimethylsulfoxide and K562 cells stimulated by cytosine arabinoside or hemin. The genomic sequence of T beta 4 is considered to be highly conserved. Only 1 of 20 genomes from normal or hematopoietic malignant cells showed restriction fragment length polymorphism. These findings, along with previous data, suggest that T beta 4 may be a new marker of differentiation of hematopoietic cells.

Adult↗
PubMed1990

Purification of a granulocyte colony-stimulating factor from the conditioned medium of a subclone of human bladder carcinoma cell line 5637, HTB9.

A colony-stimulating factor (CSF) has been purified to homogeneity from the conditioned medium (CM) of a subclone, designated HTB9, of human bladder carcinoma cell line 5637. HTB9 cells were successfully cultured on micro-carrier beads at low-serum concentration, and the resulting CM (HTB9-CM) was concentrated by ultrafiltration. Purification procedures consisted of anion-exchange column chromatography, gel-filtration column chromatography, and reverse-phase column chromatography. The finally purified protein possessed a specific activity more than 10(8) U/mg protein for day-7 CFU-GM colony formation and exhibited a single band representing a molecular weight of 17,000 upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Biological activity was apparently specific for a neutrophilic granulocyte lineage of human non-phagocytic bone-marrow cells in vitro, and antiserum raised against this purified protein completely inhibited the activity of recombinant granulocyte colony-stimulating factor.

Chromatography, Gel↗
PubMed1990

Methylcholanthrene-induced murine fibrosarcoma cell line BMT-11 secretes granulocyte colony-stimulating factor.

Murine fibrosarcoma cell line BMT-11 was induced with 3-methylcholanthrene and maintained in culture. Transplantation of BMT-11 into syngeneic C57BL/6 mice produced leukocytosis consisting of marked increments of neutrophils and monocytes associated with massive splenomegaly. In order to elucidate the mechanisms of this leukemoid reaction, we studied the changes occurring in hematopoietic progenitor cells in BMT-11-transplanted mice. The numbers of granulocyte-macrophage colony-forming units (CFU-GM), erythroid colony-forming units (CFU-E), erythroid burst-forming units (BFU-E), and mixed colony-forming units (CFU-Mix) in the spleen showed dramatic 216-fold, 18-fold, 64-fold, and 80-fold increases, respectively, relative to the value in the control mice 5 weeks after the BMT-11 implantation. In contrast, the levels of progenitor cells in the bone marrow remained within normal limits. The nature of the colony-stimulating factor (CSF) secreted from BMT-11 tumor cells was also studied. BMT-11-conditioned medium (BMT-11-CM), BMT-11 tumor extract, and sera from the mice bearing transplanted BMT-11 tumor contained CSF that stimulated mainly granulocyte and macrophage lineages. Furthermore, the expression of the granulocyte colony-stimulating factor (G-CSF) gene in BMT-11 cells were detected by Northern blot analysis.

Animals↗
PubMed1990

Treatment of myelodysplastic syndrome and atypical leukemia with low-dose aclarubicin.

To study the therapeutic effect of low-dose aclarubicin (ACR), we carried out comparative treatment of 15 patients with myelodysplastic syndrome (MDS) and atypical leukemia using this drug. Complete remission (CR) was achieved in three patients with RAEB-t and one patient with AML, partial remission was obtained in one patient with RAEB and hematological improvement in one patient with refractory anemia (RA). Interestingly, prolonged CR for more than 26 months with persistent chromosomal abnormalities was observed in a case of AML, which progressed from RA. Myelosuppression caused by low-dose ACR was milder than that caused by low-dose Ara-C. Furthermore, in vitro studies indicated that ACR induced differentiation of bone marrow cells from one patient with MDS. From these observations, it is suggested that low-dose ACR may be an alternative to low-dose Ara-C for treatment of MDS, and that the in vivo effect of ACR may be mediated by the differentiation of abnormal hemopoietic clones.

Aclarubicin↗
PubMed1990

Muroctasin [MDP-Lys(18)] augments the production of granulocyte colony-stimulating factor (G-CSF) from human peripheral blood mononuclear cells in vitro.

N2-[(N-acetylmuramoyl)-L-alanyl-D-isoglutaminyl]-N6-stearoyl-L-Lysine (MDP-Lys(L18), muroctasin) is an immunopotentiating substance. Neutrophilia and elevated levels of colony-stimulating factor (CSF) in peripheral blood were previously found after the administration of this compound in both mice and humans. To specify the type of CSF and to elucidate the mechanisms of the neutrophilia, we cultured human peripheral blood mononuclear cells (PBMC) in the presence of muroctasin and measured the levels of granulocyte CSF (G-CSF) in the culture supernatants using our sensitive enzyme-linked immunosorbent assay. G-CSF is an active hematopoietic growth factor specific for cells of a neutrophilic lineage, and muroctasin was found to significantly augment the G-CSF production from PBMC in vitro (P less than 0.01). Furthermore, production of G-CSF from human PBMC in the presence of muroctasin was also supported by the Northern blot analysis using cDNA encoding G-CSF as a probe.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Conditional mutations occur predominantly in highly conserved residues of RNA polymerase II subunits.

Conditional mutations in the Saccharomyces cerevisiae RNA polymerase II large subunit, RPB1, were obtained by introducing a mutagenized RPB1 plasmid into yeast cells, selecting for loss of the wild-type RPB1 gene, and screening the cells for heat or cold sensitivity. Sequence analysis of 10 conditional RPB1 mutations and 10 conditional RPB2 mutations revealed that the amino acid residues altered by these distinct mutations are nearly always invariant among eucaryotic RPB1 and RPB2 homologs. These results suggest that RNA polymerase mutants might be obtained in other eucaryotic organisms by alteration of these invariant residues.

Amino Acid Sequence↗
PubMed1990

Genetic exploration of interactive domains in RNA polymerase II subunits.

The two large subunits of RNA polymerase II, RPB1 and RPB2, contain regions of extensive homology to the two large subunits of Escherichia coli RNA polymerase. These homologous regions may represent separate protein domains with unique functions. We investigated whether suppressor genetics could provide evidence for interactions between specific segments of RPB1 and RPB2 in Saccharomyces cerevisiae. A plasmid shuffle method was used to screen thoroughly for mutations in RPB2 that suppress a temperature-sensitive mutation, rpb1-1, which is located in region H of RPB1. All six RPB2 mutations that suppress rpb1-1 were clustered in region I of RPB2. The location of these mutations and the observation that they were allele specific for suppression of rpb1-1 suggests an interaction between region H of RPB1 and region I of RPB2. A similar experiment was done to isolate and map mutations in RPB1 that suppress a temperature-sensitive mutation, rpb2-2, which occurs in region I of RPB2. These suppressor mutations were not clustered in a particular region. Thus, fine structure suppressor genetics can provide evidence for interactions between specific segments of two proteins, but the results of this type of analysis can depend on the conditional mutation to be suppressed.

Alleles↗
PubMed1990

Influence of bestatin on production of granulocyte-macrophage colony-stimulating factor from human peripheral blood mononuclear cells in vitro.

Bestatin, (25, 3R)-3-amino-2-hydroxy-4-phenylbutyryl-L-leucine, enhanced proliferation of normal human bone marrow granulocyte-macrophage progenitor cells to form CFU-GM colonies in viscous methylcellulose medium in vitro. To elucidate the mechanisms of this effect, the levels of colony-stimulating factor (CSF) in culture supernatant of 1 x 10(6)/ml peripheral blood mononuclear cells (PBMC) cocultured with various concentrations of bestatin were determined using our newly developed sandwich enzyme-linked immunosorbent assay (ELISA). The level of granulocyte/macrophage-CSF (GM-CSF) in the supernatant in the presence of 0.1 microgram/ml bestatin was 312 pg/ml by this ELISA. The production of GM-CSF increased with increasing amounts of added bestatin.

Cells, Cultured↗
PubMed1990

Serum granulocyte colony-stimulating factor levels in chronic neutropenia of infancy.

Eight infants with chronic neutropenia ranging in age from 1 to 13 months were studied for serum granulocyte colony-stimulating factor (G-CSF) levels. Serum G-CSF levels were elevated, especially when peripheral blood absolute neutrophil counts (ANC) were under 500/microliter in seven patients with autoimmune neutropenia. On the other hand, in a patient with congenital agranulocytosis (Kostmann type), G-CSF levels were below the sensitivity of the assay (less than 50 pg/ml) despite severe neutropenia (less than 100/microliter).

Autoantibodies↗
PubMed1990

Direct action of human granulocyte colony-stimulating factor on mature human neutrophils: flow-cytometric analysis.

The direct effects of human granulocyte colony-stimulating factor (G-CSF) on mature neutrophils in vitro were studied using flow cytometry. G-CSF increased the neutrophil forward scatter without recruitment of side scatter, as assessed by flow cytometry. This indicates that G-CSF acts on neutrophils directly and induces the activation of mature neutrophils without degranulation of primary granules.

Colony-Stimulating Factors↗
PubMed1990

Drug sensitivity test for acute myeloblastic leukemia by an efficient leukemic blast colony assay using 5637-conditioned medium as a stimulator.

Drug sensitivity of clonogenic leukemic blast cells was measured using the leukemic blast colony formation technique. Each of three chemotherapeutic agents, cytosine arabinoside, daunorubicin and aclarubicin, was added at the start of culture, and sensitivity was measured in terms of numbers of surviving leukemic blast colonies formed under continuous exposure to the drug. A substantial number of colonies was observed in all cases examined when the conditioned medium of human bladder carcinoma cell line 5637 was used as the leukemic blast colony stimulator. Although drug sensitivity varied considerably among the cases examined, sensitivity to administered drugs in clinical non-responders was significantly poorer than that in clinical responders (p less than 0.05).

Aclarubicin↗
PubMed1990

Production of interleukin-6 from macrophages by MDP-Lys (L 18), romurtide.

N2-[(N-Acetylmuramoyl)-L-alanyl-D-isoglutaminyl-N6-stearoyl-L-lysine [MDP-Lys(L18), romurtide] is an immunopotentiating substance. In addition to neutrophilic leukocytosis, the effects previously found after the administration of this compound in both mice and humans were thrombocytosis and elevated levels of colony-stimulating factor (CSF) in peripheral blood. Although the exact mechanism of thrombopoiesis is not yet known, evidence has been accumulating that interleukin-6 (IL-6) plays an important role in the maturation of megakaryocytes, and the administration of IL-6 has been reported to induce a significant increase in blood platelets associated with promotion of megakaryocyte maturation. We measured the IL-6 levels in the culture supernatants of peripheral blood mononuclear cells (PBMCs), adherent cells and nonadherent cells in the presence of romurtide. Significant augmentation of IL-6 from PBMCs and adherent cells, but not nonadherent cells, was observed in the presence of romurtide in vitro.

Acetylmuramyl-Alanyl-Isoglutamine↗
PubMed1990

Both granulocyte-macrophage colony-stimulating factor and monocytic colony-stimulating factor are produced by the human T-cell line, HUT 102.

We present the first report of a T-helper cell line, HUT 102, constitutively producing both granulocyte-macrophage colony-stimulating factor (GM-CSF) and monocytic colony-stimulating factor (M-CSF), as detected by sensitive enzyme-linked immunosorbent assays and Northern blot analysis. However, neither amplification nor structural change of the GM-CSF and M-CSF genes was detected by Southern blot analysis. In the case of HUT 102, in which human T-lymphotropic leukemia virus type I (HTLV-I) is integrated, the viral protein, which acts as a trans-acting transcriptional activator, may induce the production of both GM-CSF and M-CSF.

Cell Line↗