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Biomedical subjects

M Shimoyama

Publications and source records attributed to M Shimoyama.

At least 235 records · Page 13Linked to original sources
PubMed1986

Structure of HTLV and its biological function in leukemogenesis of adult T-cell leukemia.

There is a high homology of nucleotide sequence between 3' two-thirds of the X (or pX) regions of human T-cell leukemia virus (HTLV)-I, and of HTLV-II. Monoclonal antibody against p41 coded from X-IV, an open reading frame of X region of HTLV-I, was established. Two proteins coded by Xb, one of the open reading frames in X region of HTLV-II, were newly identified as p24 and p26. The expression of X protein of HTLV-II in the reconstituted mouse embryonal carcinoma cell line, which shows myoblastic morphology, reverted the morphology to that of the original embryonal carcinoma cells. This suggests that the function of X protein is to disturb the regulation of cell lineage determination. Leukemogenesis of adult T-cell leukemia (ATL) is also considered to consist of multisteps, in which HTLV-I constitutes one step, other factors also being involved. Even the role of HTLV-I factor could be similarly played by other factor(s). In agreement with this hypothesis, there are patients with ATL without associated HTLV-I.

Adult↗
PubMed1986

Influence of fetal calf serum on growth-inhibitory activity of human recombinant gamma-interferon (GI-3) in vitro.

The growth-inhibitory activity of human recombinant gamma-interferon (rIFN-gamma: GI-3) against 30 human cultured cell lines derived from leukemias and lymphoma (9 T-cell, 13 B-cell, 2 nonTnonB and 6 myeloid cell lines) was measured quantitatively by in vitro regrowth assay. Only three myelomonocytoid cell lines (HL-60, U937 and THP-1-0) were found to be sensitive, and HL-60 was the most sensitive. However, the sensitivity of HL-60 was found to be much influenced by both the batch and the concentration of fetal calf serum (FCS) used in the experiment. In the experiments using a certain FCS, GI-3 had a high antiproliferative activity against HL-60 at the optimal concentration (10(4)-10(5) U/ml), when assayed in medium containing 10% FCS. Both lower and higher concentrations of the interferon than 10(4)-10(5) U/ml resulted in decreased antiproliferative activity. When a high concentration (30%) of the FCS was employed in the assay, the antiproliferative activity of GI-3 was also much reduced. In the experiments using the other FCS, no antiproliferative activity of GI-3 against HL-60 was observed on assay in the medium containing 10% FCS, but significant antiproliferative activity was observed in the medium containing 30% FCS from the same source. Experiments using serum-free culture medium revealed that GI-3 itself had both a slight growth-inhibitory action at the optimal concentrations (at about 10(4) U/ml) and growth-enhancing activity at high (10(6) U/ml) concentration. The antiviral titer of GI-3 was stable during 72 hr of incubation in growth medium with or without cells. These findings suggest that there are cofactors in the serum which positively or negatively influence the growth-regulatory activity of GI-3 against HL-60 cells.

Cell Division↗
PubMed1986

[VEPA therapy in B-lymphoma].

48 previously untreated adult patients with B-lymphoma were treated with VEPA therapy. The complete remission rate was 79.2%. 48% of the patients were still alive after 4 years of the therapy. About 90% of the patients of stage II was expected to be cured by the therapy. VEPA therapy is greatly effective to B-lymphoma.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed1986

Cell surface markers of acute non-lymphocytic leukemias: leukemia type and its expression of C3 and Fc receptors.

Seventeen untreated human acute non-lymphocytic leukemias (ANLL) were classified into four groups according to the presence or the absence of complement receptor and Fc receptor for IgG and IgM: Group I having neither C3 nor Fc receptors, Group II having either C3 or Fc receptor and Group III having both C3 and Fc receptors. ANLL of Group II was further subdivided into two groups: Group IIa having only Fc receptor and Group IIb having only C3 receptor. The morphologic and cytochemical analysis of ANLL in these groups revealed that the most immature type with regard to their myeloid-monocyte lineage was Group IIb followed by Groups I, IIa and III. Two cases of Group IIb were regarded as M1 type by French-American-British (FAB) group classification and one of them had a Ph1-chromosome. The survival rate of patients in each group was investigated and Group IIb patients showed the tendency for the longest period of survival.

Acute Disease↗
PubMed1985

Amino acid sequence of histone H1 at the ADP-ribose-accepting site and ADP-ribose X histone-H1 adduct as an inhibitor of cyclic-AMP-dependent phosphorylation.

The ADP-ribosylation site of histone H1 from calf thymus by purified hen liver nuclear ADP-ribosyltransferase was determined and effects of the ADP-ribose X histone-H1 adduct on cAMP-dependent phosphorylation of the histone H1 were investigated. ADP-ribosylated histone H1 was prepared by incubation of histone H1, 1 mM [adenylate-32P]NAD and the purified ADP-ribosyltransferase. N-Bromosuccinimide-directed bisection of ADP-ribosylated histone H1 showed that the NH2-terminal fragment (Mr = 6000) was modified and contained serine residue 38, the site of phosphorylation by cAMP-dependent protein kinase. Digestion of the NH2-terminal fragment with cathepsin D and trypsin, and purification of this fragment, using high-performance liquid chromatography, yielded a radiolabelled single peptide corresponding to residues 29-34 of histone H1, containing the arginine residue as the ADP-ribosylation site. These results indicate that ADP-ribosylation of histone H1 occurs at the arginine residue 34, sequenced at the NH2-terminal side of the phosphate-accepting serine residue 38. Phosphorylation of histone H1 from calf thymus by cAMP-dependent protein kinase was markedly reduced when histone H1 was ADP-ribosylated. Kinetic studies of phosphorylation revealed that ADP-ribosylated histone H1 was a linear competitive inhibitor of histone H1 and a linear non-competitive inhibitor of ATP.

Adenosine Diphosphate Ribose↗
PubMed1985

Methylation pattern of human T-cell leukemia virus in vivo and in vitro: pX and LTR regions are hypomethylated in vivo.

The methylation patterns of the gag, pol, env, pX and LTR regions of proviral DNA of human T-cell leukemia/lymphoma virus type I (HTLV) in fresh leukemic cells and established cell lines were examined using HpaII/MspI endonuclease. Peripheral blood lymphocytes (PBL) isolated from patients with adult T-cell leukemia/lymphoma (ATL) did not express viral antigens of HTLV, but PBL that had been cultured for 2 days did express these viral antigens. Most parts of the gag, pol and env regions of the HTLV provirus in PBL isolated from 12 ATL patients and PBL cultured for 2 days were hypermethylated as reported by others. In contrast, in 10 established cell lines that harbored HTLV genomes and expressed viral antigens, HTLV proviruses were hypomethylated. In one cell line, ATL-IK, which harbored an HTLV genome but did not produce viral antigens, the gag, pol and env regions were hypermethylated. However, two HpaII sites, one in the middle of the gag region and the other in the middle of the pol region, were not methylated even in PBL from most ATL patients. Furthermore, the pX and LTR regions were hypomethylated not only in established cell lines but also in PBL of ATL patients. The hypomethylation of the pX and LTR regions detected in fresh leukemic cells of ATL patients may have some etiological significance in cell transformation by controlling the level of transcription of these regions, or modulating the binding of some factors to these regions.

Adult↗
PubMed1985

ADP-ribosylation of phosphorylase kinase and block of phosphate incorporation into the enzyme.

Phosphorylase kinase purified from rabbit skeletal muscle was ADP-ribosylated by hen liver nuclear ADP-ribosyltransferase. This modification, as was seen in cAMP-dependent phosphorylation, was observed only in alpha and beta subunits of the phosphorylase kinase and the latter was more rapidly modified. Analysis of the ADP-ribosylated amino acid residue sequenced in alpha and beta subunits showed that both subunits were modified at the area of the arginine residue. The Km for NAD was 0.10 mM and the pH optimum was 9.0. When the ADP-ribosylated phosphorylase kinase was phosphorylated by cAMP-dependent protein kinase, a reduction in phosphate incorporation occurred with increase in the ADP-ribosylation. ADP-ribosylation also suppressed autophosphorylation, to a lesser degree than observed with cAMP-dependent phosphorylation. The ADP-ribosylation-dependent reduction of phosphorylation resulted in a suppression of the phosphorylation-dependent activation of the phosphorylase kinase. These results together with findings of ADP-ribosyltransferase activity in the rabbit skeletal muscle [Soman, G. et al. (1984) Biochem. Biophys. Res. Commun. 120, 973-980] suggest that ADP-ribosylation participates in the regulation of the phosphorylase kinase activity through changes in the rate of phosphorylation.

Adenosine Diphosphate Ribose↗