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Biomedical subjects

M Tsuchiya

Publications and source records attributed to M Tsuchiya.

At least 397 records · Page 22Linked to original sources
PubMed1987

ADP-ribosylation of Ca2+-dependent ATPase in vitro suppresses the enzyme activity.

We investigated the effect on the Ca2+-dependent ATPase activity of ADP-ribosylation of the enzyme from the rabbit skeletal muscle sarcoplasmic reticulum. A reconstituted ADP-ribosylation system of Ca2+-dependent ATPase in which the enzyme and ADP-ribosyltransferase, both were partially purified from the vesicles, and poly L-lysine were contained, was preincubated with 1 mM NAD, and the Ca2+-dependent ATPase activity was assayed. The NAD-dependent suppression of the enzyme activity depended on both the concentration of NAD and preincubation-time for the ADP-ribosylation, and was reversed by adding 20 mM arginine during the preincubation. These results taken together with the findings that Ca2+-dependent ATPase is a major acceptor protein for the modification in rabbit skeletal muscle sarcoplasmic reticulum [Hara et al. (1987) Biochem. Biophys. Res. Commun. 144; 856-862] suggest that Ca2+-transport in the sarcoplasmic reticulum may be regulated through changes in the rate of ADP-ribosylation of Ca2+-dependent ATPase.

Adenosine Diphosphate Ribose↗
PubMed1987

Chromosomal gene structure of human myeloperoxidase and regulation of its expression by granulocyte colony-stimulating factor.

By using the full-length cDNA as a probe, the chromosomal gene for human myeloperoxidase was isolated from a human gene library. Comparison of the nucleotide sequence of the chromosomal gene with that of the cDNA has revealed that the human myeloperoxidase gene is composed of 12 exons and 11 introns. S1 mapping analysis of human myeloperoxidase mRNA identified the single transcription initiation site at 180 base pairs upstream of the ATG initiation codon. In the 5'-flanking region of the human myeloperoxidase gene, there are several blocks of sequences which are homologous to the sequences found on the 5'-promoter region of the human c-myc proto-oncogene. The myeloperoxidase gene is expressed in mouse myeloid leukemia WEHI-3B D+ and NFS-60 cells. When these cells were treated with human recombinant granulocyte colony-stimulating factor, the steady-state level of myeloperoxidase mRNA declined to zero within 36 h in WEHI-3B D+ cells, but not in NFS-60 cells.

Amino Acid Sequence↗
PubMed1987

The chromosomal gene structure for murine granulocyte colony-stimulating factor.

The chromosomal gene for murine granulocyte colony-stimulating factor (G-CSF) has been isolated from a mouse genomic library. The nucleotide sequence analysis of the gene and its flanking region has revealed that the murine G-CSF gene is composed of four introns and five exons, which is similar to the human G-CSF gene. The S1 mapping analysis of murine G-CSF mRNA has identified the major transcription initiation site for the murine G-CSF gene at 36 base pairs upstream of the ATG initiation codon. In the flanking region, there are sequences of about 300 base pairs which are highly conserved between human and murine G-CSF genes. The decanucleotide GAGRTTCCAC, which was found at the 5'-flanking region of genes for other hemopoietic growth factors, was also present within the corresponding regions of human and murine G-CSF gene. Unlike the human G-CSF gene, no alternative splicing was observed for the murine G-CSF gene.

Amino Acid Sequence↗
PubMed1987

Mono(ADP-ribosyl)ation of Ca2+-dependent ATPase in rabbit skeletal muscle sarcoplasmic reticulum and the effect of poly L-lysine.

We investigated the endogenous mono(ADP-ribosyl)ation of the sarcoplasmic reticulum from rabbit skeletal muscle. The autoradiogram obtained after sodium dodecyl sulfate-polyacrylamide gel electrophoresis of the [adenylate-32P]NAD-treated sarcoplasmic reticulum vesicles revealed a major band corresponding to the MW 105 K Ca2+-dependent ATPase and other bands corresponding to proteins of MW 153, 60 and 38 K and those of 125 to 135 K range. The addition of poly L-lysine during the incubation led to an enhancement of the modification. Poly L-lysine is proving to be a pertinent tool for identifying acceptor proteins.

Adenosine Diphosphate Ribose↗
PubMed1987

Characterization of recombinant human granulocyte-colony-stimulating factor produced in mouse cells.

Mouse C127I cells were transformed with a chimeric plasmid consisting of bovine papillomavirus DNA and human granulocyte-colony-stimulating factor (G-CSF) cDNA placed under the control of the SV40 early promoter. The transformed cells secreted constitutively a high level of human G-CSF, 10-20 micrograms/ml in a low-serum medium. The secreted G-CSF has been purified to homogeneity by a two-step procedure including gel filtration and hydrophobic column chromatography. The purified recombinant G-CSF runs as a single band with an apparent Mr of 19,000 on a polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate. This value corresponds to that of the native human G-CSF purified from the medium conditioned by human carcinoma CHU-2 cells. The recombinant human G-CSF was as active as native G-CSF in vitro in supporting proliferation of mouse NFS-60 cells and stimulating colony formation from human as well as mouse bone marrow cells. When the recombinant human G-CSF was subcutaneously administrated into mice, a remarkable stimulation of granulopoiesis and splenomegaly was observed.

Animals↗
PubMed1987

In vitro effect of a thymic epithelial culture supernate or thymosin fraction 5 on rabbit platelet aggregation and intracellular cyclic AMP levels.

Supernates of thymic epithelial cell culture (STEC) strongly inhibit aggregation induced by addition of adenosine diphosphate (ADP: 1 microM) or thrombin (0.5 unit per ml) to washed platelet suspensions and accelerated the restoration from ADP-triggered aggregation. At the same time, STEC increased the level of platelet adenosine 3',5'-cyclic monophosphate (cyclic AMP) in a dose-dependent manner. Depending on the concentration used, thymosin fraction 5 increased the level of intracellular cyclic AMP ranging between 5 and 100 micrograms per ml, as well as inhibiting ADP-induced platelet aggregation. The activities of both STEC and thymosin fraction 5 were found to act exclusively on cyclic AMP phosphodiesterase activity in platelets. In contrast the supernates from Chang, HeLa, or HCC-M cells did not affect platelet aggregation induced by ADP, but slightly increased the cyclic AMP level (Chang, HeLa). Within 2 min after the treatment with STEC, more than 50% of the maximum inhibitory activity on platelet aggregation and increases in intracellular cyclic AMP were observed. These activities disappeared following STEC treatment with pronase E. STEC activity was found predominantly in the 1,000-50,000-dalton fractions. These activities were not altered when STEC was treated by adenosine deaminase. The level of prostaglandin E (PGE) derivatives in STEC was about two times that found in the control culture medium. These data suggest that the biological activity of STEC in the platelets might be attributed to thymosinlike polypeptides and PGE1.

Adenosine Deaminase↗
PubMed1987

Human gene coding for granulocyte-colony stimulating factor is assigned to the q21-q22 region of chromosome 17.

Granulocyte-colony stimulating factor (G-CSF) is a member of colony stimulating factors which regulate the proliferation and differentiation of hematopoietic progenitor cells. A full-length cDNA clone coding human G-CSF was used as a hybridization probe to detect homologous sequence in human-mouse somatic cell hybrids, flow-sorted human chromosomes, and in situ human metaphase chromosomes. The results indicate that the gene encoding human G-CSF is on the q21-q22 region of chromosome 17, which is involved in translocation of t(15;17) (q23;21) in human acute promyelocytic leukemia.

Animals↗
PubMed1987

Lysosomal enzymes in tear fluids from patients with Terrien's marginal corneal degeneration.

We examined biochemically the lysosomal enzyme activities in tear fluids from patients with mild myopia, senile cataract, and Terrien's marginal corneal degeneration. Tear acid phosphatase activities in Terrien's degeneration were almost the same as those in mild myopia and senile cataract, while those of N-acetyl-beta-D-glucosaminidase in Terrien's degeneration were higher. The high activity of tear N-acetyl-beta-D-glucosaminidase may be derived from the lacrimal gland and infiltrate histiocytelike cells in Terrien's marginal corneal degeneration.

Acetylglucosaminidase↗
PubMed1987

Transformation of NIH/3T3 cells by DNA from a human hepatoma cell line with integrated hepatitis B virus DNA.

We have studied by means of DNA-mediated gene transfer the transforming activity of the DNA of the human hepatoma cell line HCC-M, which contains genomes of hepatitis B virus (HBV) in integrated form. DNA from HCC-M induced transformed foci on transfection of NIH/3T3 cells. DNAs from primary transformants were capable of inducing secondary transformants. Most of the DNAs of these transformants were demonstrated to contain both human repetitive sequences and HBV DNA, indicating that the transformants had incorporated exogenous human DNA and HBV DNA as well. These results suggest that transformation occurs as the result of the transfer of oncogene which might be closely associated with HBV genome.

Carcinoma, Hepatocellular↗
PubMed1987

Increased adenylate energy charges in rat liver or primary cultured rat hepatocytes by diisopropyl 1,3-dithiol-2-ylidenemalonate.

Six hours after oral administration in rat liver, diisopropyl 1,3-dithiol-2-ylidenemalonate (malotilate) decreased AMP concentrations by 60% with unchanged total adenine nucleotide concentrations and significantly increased adenylate energy charges of 0.87 in comparison to those of 0.81 in vehicle administered control animals. Twelve hours after incubation in primary cultured rat hepatocytes, malotilate decreased AMP concentrations by 18% and increased ATP and GTP concentrations by 13 and 18% respectively with significantly increased adenylate energy charges of 0.89 in comparison to 0.87 in vehicle control. Increased adenylate energy charges by malotilate coincided with the initiation of increases in protein and de novo purine synthesis in vivo, and are associated with the increased rate of de novo purine synthesis in vitro.

Adenine Nucleotides↗
PubMed1987

Glucagon infusion increases rate of purine synthesis de novo in rat liver.

Based on the parallel increases of glucagon, the second peak of hepatic cAMP, and the rate of purine synthesis de novo in the prereplicative period in regenerating rat liver after a 70% hepatectomy, it was hypothesized that glucagon is responsible for the increased rate of purine synthesis de novo. To test this hypothesis, the effect of glucagon or dibutyryl cAMP infusion on the rate of purine synthesis de novo in rat liver was studied. Glucagon infusion but not insulin or glucose infusion increased the rate of purine synthesis de novo, which was assayed by [14C]glycine or [14C]formate incorporation, by 2.7- to 4.3-fold. Glucagon infusion increased cAMP concentrations by 4.9-fold and 5-phosphoribosyl-1-pyrophosphate concentrations by 1.5-fold in liver but did not change the specific activity of amidophosphoribosyltransferase (EC 2.4.2.14) or purine ribonucleotide concentrations. Dibutyryl cAMP infusion also increased the rate of purine synthesis de novo by 2.2- to 4.0-fold. Because glucagon infusion increased the rate of purine synthesis de novo in the presence of unchanged purine ribonucleotide concentrations, it is concluded that glucagon after infusion or in animals after a 70% hepatectomy is playing an anabolic role to increase the rate of purine synthesis de novo by increasing cAMP and 5-phosphoribosyl-1-pyrophosphate concentrations.

Amidophosphoribosyltransferase↗
PubMed1987

Inhibitory effect of somatostatin on cholera toxin-induced diarrhea and glycoenzyme secretion in rat intestine.

The effects of somatostatin on cholera toxin-induced secretory diarrhea and the appearance of glycoenzymes in the intestinal lumen and intestinal lymph were investigated in rat small intestine. After exposure to cholera toxin, marked fluid accumulation in the small intestinal tract and elevation of the jejunal mucosal cyclic AMP (cAMP) concentration were observed. The activity of alkaline phosphatase, aminopeptidase and sucrase increased in the intestinal lumen after toxin exposure. In intestinal lymph, alkaline phosphatase activity was increased after cholera toxin administration, while aminopeptidase activity remained unchanged. Somatostatin suppressed cholera toxin-induced secretory diarrhea, but it did not affect the elevated mucosal cAMP concentration. This peptide also inhibited the appearance of glycoenzymes in the intestinal lumen and lymph induced by cholera toxin administration. These results suggest that somatostatin exerts its inhibitory effects on cholera toxin-induced secretory diarrhea and on the appearance of glycoenzymes in the intestinal lumen and lymph by affecting processes beyond cAMP formation.

Alkaline Phosphatase↗
PubMed1987

Effect of angiotensin converting enzyme inhibitor (captopril) on cerebral blood flow in hypertensive patients without a history of stroke.

The effect of the angiotensin converting enzyme inhibitor, captopril, on cerebral blood flow (CBF) was studied in 11 hypertensives without a history of stroke. Mean hemispheric CBF (mCBF) was measured in each patient by Xe-133 inhalation method before and after 7 days of captopril administration. Blood pressure (BP) both in the control state and at the time of CBF measurement decreased significantly after drug administration. mCBF, however, did not show any significant change. When percent changes in mCBF before and after the administration were plotted against those of mean arterial BP, significant inverse correlations were obtained in both hemispheres; the larger the BP decrease, the more increase in CBF was observed. It is concluded that captopril lowers systemic BP without concomitant decrease in CBF in hypertensive subjects with no history of stroke. Furthermore, the results suggest that captopril may have a vasodilating action on cerebral blood vessels.

Adult↗
PubMed1987

Sulfasalazine and its metabolites attenuate respiratory burst of leukocytes--a possible mechanism of anti-inflammatory effects.

The effects of sulfasalazine and its metabolites, 5-amino salicylic acid and sulfapyridine on respiratory burst of polymorphonuclear leukocytes were investigated by determining not only luminol-dependent chemiluminescence for the detection of myeloperoxidase-mediated active oxidants, but also lucigenin-dependent chemiluminescence for the detection of superoxide anion. The present study showed that sulfasalazine, 5-amino salicylic acid and sulfapyridine attenuated active oxygen species from polymorphonuclear leukocytes at the concentrations comparable to clinical doses. Therefore, it was concluded that anti-inflammatory effects of sulfasalazine can be explained by the ability of sulfasalazine and its degraded compounds to scavenge active oxidants from polymorphonuclear leukocytes.

Aminosalicylic Acids↗