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Biomedical subjects

M Tsuchiya

Publications and source records attributed to M Tsuchiya.

At least 19 recordsLinked to original sources
PubMed1992

Visualization of oxidative processes at the cellular level during neutrophil-mediated cytotoxicity against a human hepatoma cell line, HCC-M.

Human neutrophil-mediated oxidative processes against a human hepatoma cell line, HCC-M, was visualized at the cellular level by using a silicon-intensified target camera and subsequently processing with a computer-assisted digital-imaging processor. Neutrophils were activated by a streptococcal preparation, OK-432. A hydroperoxide-sensitive tracer, dichlorofluorescein diacetate, was loaded in HCC-M and temporal and spatial changes of lipid peroxides in this cell after addition of stimulated neutrophils were analyzed. The luminol-dependent chemiluminescence activity of neutrophils was significantly enhanced and continued for at least 2 hr by stimulation with OK-432, and its activity was shown to be accumulated at the site where a neutrophil attached with HCC-M. The intensity of dichlorofluorescein fluorescence in HCC-M rapidly increased after adding stimulated neutrophils, and their reaction was significantly attenuated by superoxide dismutase. The number of non-viable cells was increased as the dichlorofluorescein fluorescence increase. It is suggested that oxidative stress may play an important role in neutrophil-mediated tumor-cell damage.

Carcinoma, Hepatocellular↗
PubMed1992

Microtopographic analysis of oxidative stress in organ microcirculatory units.

Current approaches for visualization of oxidative stress in organ microcirculatory units were summarized. Recent development of digital imaging photonic microscopy has made it possible to analyze spatial and temporal alterations of oxyradical generation during tissue injury. Luminol-dependent photonic imagery revealed granulocyte-mediated oxidative stress during microvascular damages, suggesting that the interface between venular endothelium and sticking granulocytes may be the most critical site of oxidative stress. Fluorographic analysis assisted by dichlorofluorescin (DCFH) diacetate is a powerful tool to visualize intracellular hydroperoxide formation. This method demonstrated intralobular heterogeneity of oxidative stress in the isolated perfused hepatic microcirculatory units exposed to either CCl4 or low-flow hypoxia. CCl4 caused the activation of dichlorofluorescein (DCF) predominantly in perivenular areas, while the 25% low-flow perfusion induced periportal or midzonal DCF activation. Refinement of the present technique will provide further insight into the microtopographic correlation between oxidative stress and tissue breakdown in microcirculation.

Animals↗
PubMed1992

Conservation of a 23-kDa human transplantation antigen in mammalian species.

A group of transplantation antigens, referred to as tum- antigens, were identified in mouse tumor cells that had been mutagenized to produce variant cells and were recognized by clonal cytolytic T lymphocytes (CTL). Alterations in these variant cells that were recognized by CTL resulted from point mutations in the genes of specific proteins. We have isolated human and bovine cDNA clones that encode the homologs of the mouse tum- antigen P198. This 23.6-kDa protein is highly basic with a predicted pI of 11.55. p23/P198 is highly conserved across mammalian species, with > 94% identity (97% including conservative substitutions) among the human, bovine, and mouse deduced amino acid sequences. The nucleotide sequences of both the coding and 5'- and 3'-untranslated regions from human, bovine, and mouse are also highly conserved with > 88% identity in the coding regions. Hybridization of poly(A)+ RNA from various mammalian sources with cDNA and oligonucleotides specific for the coding region identified two mRNAs of 1.2 and 0.8 kb, whereas probes specific for the 3'-untranslated region between two consensus polyadenylation signals hybridized with the 1.2-kb, but not the 0.8-kb, mRNA. The abundance of the 1.2-kb mRNA relative to that of the 0.8-kb species varied depending upon the cell type. A single predominant transcription initiation site was mapped by primer extension. These studies indicate that this highly basic 23.6-kDa protein is encoded by two major mRNA species that differ only in the length of their 3'-untranslated regions and that the mechanism that gives rise to these two mRNAs, utilization of alternative polyadenylation sites, is conserved across species.(ABSTRACT TRUNCATED AT 250 WORDS)

Amino Acid Sequence↗
PubMed1992

Elevated ratio of late measles among subacute sclerosing panencephalitis patients in Karachi, Pakistan.

Subacute sclerosing panencephalitis (SSPE) in Western countries and Japan is found more often in early- than in late-measles sufferers. Recent SSPE findings in Karachi, however, present a different picture. Age at measles contraction was obtained and analyzed for 44 SSPE patients identified in Karachi between 1983 and 1988. The ratios of early- (< 2 years of age) and late- (> or = 2 years of age) measles sufferers among 36 of these patients who had experienced only one attack of measles were 0.33 and 0.67, respectively. This is in striking contrast to the predominance of early measles in the SSPE histories reported in Japan and an number of Western countries.

Age Factors↗
PubMed1992

Endogenous arginine-specific ADP-ribosyltransferases and target proteins.

We investigated vertebrate arginine-specific ADP-ribosyltransferases and target proteins for the enzyme. ADP-ribosyltransferase found in each organelle ADP-ribosylated preferentially an endogenous acceptor protein co-localized with the enzyme. We propose that the ADP-ribosylation of tissue-specific target protein by the endogenous ADP-ribosyltransferase may participate in the regulation of cellular processes, including signal transduction.

ADP Ribose Transferases↗
PubMed1992

Effect of dexamethasone, dimethylsulfoxide and sodium butyrate on a human hepatoma cell line PLC/PRF/5.

The effects of agents which are known to be differentiation inducers on a human hepatoma cell line PLC/PRF/5 were investigated. Dexamethasone (DEX), sodium butyrate (SB) or dimethylsulfoxide (DMSO) were examined. They all reduced cell proliferation but differ from each other in effect on the secretion of alphafetoprotein (AFP) and hepatitis B surface antigen (HBsAg), changes in morphology and RNA transcription. SB changed the cell from polygonal into a fibroblast-like type and decreased AFP secretion. DMSO decreased the cell size and changed AFP secretion in the same manner as SB. DEX changed the cell into a larger size, as well as increased AFP secretion. HBsAg secretion and also HB virus DNA transcription was enhanced by 3 agents. AFP and myc gene transcriptions were reduced by SB but DMSO reduced only AFP. Albumin gene transcription was enhanced by SB and DEX. These results indicate that the decrease of PLC/PRF/5 proliferation is induced through different mechanisms by these 3 agents.

Butyrates↗
PubMed1979

Prostaglandin F2 alpha metabolite levels in plasma, amniotic fluid, and urine during pregnancy and labor.

Levels of 13, 14-dihydro 15-keto-prostaglandin F2alpha (dhk PGF2alpha) in the plasma of 30 patients as well as in the amniotic fluid of 17 patients, and 5alpha,7alpha-dihydroxy 11-keto tetranor-prostane 1,16-dioic acid (the main urinary metabolite of PGF2alpha [PGF2alpha MUM]) levels in the urine of 30 patients were measured by radioimmunoassay during pregnancy, labor, and the puerperium. During pregnancy, no increase in dhk PGF2alpha (ng/ml) in plasma was detected as the time of delivery approached. The levels of dhk PGF2alpha during the second stage (0.64 +/- 0.15) and also at delivery (0.88 +/- 0.27) were significantly elevated over those in the first stage (0.38 +/- 0.29) (P less than 0.025 and P less than 0.005, respectively). Its level 2 hours after delivery was reduced to predelivery levels. Its levels in umbilical arterial and venous blood were 0.71 +/- 0.26 and 0.67 +/- 0.26, respectively. A significant elevation (P less than 0.01) of dhk PGF2alpha from 0.89 +/- 0.21 before labor to 6.16 +/- 2.40 at delivery was found in amniotic fluid. The hourly excretion of PGF2alpha MUM (microgram/hour) increased significantly from pregnancy levels to 1.06 +/- 0.45 in the first stage (P less than 0.01), to 7.67 +/- 4.31 (P less than 0.005) for the first 2 hours after delivery, and 2.37 +/- 1.08 from 2 to 12 hours after delivery (P less than 0.01). The excretion of PGF2alpha MUM decreased to pregnancy levels 12 hours post partum. These data indicate that during labor the production of PGF2alpha is remarkably increased.

Amniotic Fluid↗
PubMed1979

Role of plasma histamine in liver injury--clinical and experimental investigations.

Plasma histamine level (PHL) was evaluated by a modified fluorometric assay (Suzuki) in the patients with various forms of liver disease as well as rabbits with liver injury. And the data obtained were compared with liver function tests in assessing the stage and prognosis of hepatic dysfunction. In acute hepatitis, if its prognosis was "good", as was also shown in the animal group with single dose administration of CCl4, the level of plasma histamine attained a peak before that of serum transaminases, and returned to normal prior to that of the latter. In persistent and chronic hepatitis, although correlation between PHL and other liver function tests was poor and variable, PHL remained high. And the estimation of PHL during the course of this state showed that it was elevated prior to that of serum transaminases, in dicating high level of plasma histamine in this state, even in apparent "steady state", worsening of the disease. In liver cirrhosis PHL correlated with the degree of serum transaminases as well as serum gammaglobulin. In "poor prognosis" group (patients with hepatic coma and rabbits treated with consecutive administration of CCl4) PHL increased extremely high, which was contrasted with the lowered levels of transaminases. These results strikingly suggest that histamine is involved in liver injury and estimation of PHL in the course of hepatic disorder is useful for a prediction of prognosis.

Animals↗
PubMed1979

Natural biventricular hypertrophy in normotensive rats. I. Physical and hemodynamic characteristics.

The Wistar-Kyoto strain of normotensive rats (WKY) is being used as a control animal for studies involving the spontaneously hypertensive rats (SHR). A subset of the WKY demonstrating an inheritable transmission of biventricular cardiac hypertrophy (BVH) has been identified. The cardiac enlargement is pronounced, with right and left ventricular weights greater than twice normal in some animals. This natural development of BVH appears to be in response to an increased cardiac output. Blood pressure is normal and, therefore, peripheral resistance is reduced. Left ventricular injection of 15-micrometer radioactively labeled microspheres demonstrated that WKY with BVH had a substantial shunt fraction of their cardiac output (45 +/- 7% radioactivity recovered in the lungs vs. 3 +/- 2% in normal WKY). This subset of WKY with BVH provides a natural model of volume-load hypertrophy. In addition, investigators using the WKY for comparison with SHR should exclude animals with BVH.

Animals↗
PubMed1979

Effects of Panax Ginseng root on acquisition of sound discrimination behaviour in rats.

Pole-climbing and shuttle-avoidance tests were employed to study the acquisition of conditioned avoidance response (CAR) and discrimination behaviour (DB) in male Wistar rats which had been given extracts from Panax Ginseng root intraperitoneally or orally. Neither a lipid soluble fraction (GNo. 5) nor a ginsenoside Rg fraction (GRg) produced significant changes in the acquisition of CAR. GRg given intraperitoneally produced a significant acceleration in the acquisition of DB between a 500 Hz signal sound followed by an electric shock (SD) and a 1000 Hz signal sound without a shock (S delta) in rats which had learned to avoid the shock following SD at a rate of over 95%. Small doses of GNo. 5 produced a significant depression in the acquisition of DB.

Animals↗
PubMed1979

Study on the fixation method of microcirculation system for electron microscopy.

1) Although glutaraldehyde solution was injected into the superior mesenteric artery, vessels and blood cells were not fixed immediately. 2) Glutaraldehyde was considered not to be suitable for the fixation of vessels and blood cells. 3) To observe the physiological and topographical correlation of vessels and blood contents, drop osmium fixation method was better to fix the microcirculatory units immediately. 4) The perfusion of glutaraldehyde was supposed to be necessary for the fixation of the solid tissue in which microcirculatory systems exist in deeper places like liver. However, the findings observed by the perfusion method might reflex microcirculatory disturbances occured by the perfusion of glutaraldehyde itself.

Animals↗
PubMed1979

Existence of serum HBe antigen and expression of liver HB surface and core antigens in hepatitis type B patients.

A study of 52 liver biopsies (47 hepatitis type B and 5 asymptomatic carriers) was performed to clarify the roles of HBe antigen (HBeAg), HB surface antigen (HBsAg) and HB core antigen (HBcAg). In this study, the Gudat classification was modified so as to classify the patterns of HB antigens into six reaction types including: type O (negative for both liver HBsAg and liver HBcAg), type III-A (characterized by a spotty HBsAg pattern) and type III-B (characterized from a sub-lobular to lobular HBsAg localization pattern). This classification enabled accurate prediction of the prognosis of hepatitis. Patients with positive serum HBeAg had either minimal hepatitis with mild clinical features or chronic aggressive hepatitis with severe clinical features. Ten patients negative for both HBeAg and HBeAb were all positive for liver HBcAg. In all 3 patients on corticosteroid administrations liver tissue was markedly positive for HBcAg and serum was usually positive for HBeAb.

Adolescent↗