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Biomedical subjects

M Tsuchiya

Publications and source records attributed to M Tsuchiya.

At least 19 recordsLinked to original sources
PubMed1992

Determination of creatinine and ultraviolet-absorbing amino acids and organic acids in urine by reversed-phase high-performance liquid chromatography.

A simple and reliable method for the determination of urinary creatinine, amino acids and organic acids was developed. A urine sample was preliminarily separated into an organic acid fraction (including neutral species) and an amino acid fraction by cation-exchange chromatography. Both fractions were analysed by reversed-phase high-performance liquid chromatography, with a phosphoric acid-methanol gradient elution system and ultraviolet detection at 210 nm. Relationships between concentrations and peak heights were linear from 2 to 500 microM for the analytes. Overall recoveries were ca. 100%. The concentrations of creatinine for 37 urine samples, from 20 healthy newborns and from 17 patients with several inherited metabolic disorders, were 2.35 +/- 2.29 mM (ranging between 0.27 and 10.15 mM). The method was applied to the determination of several diagnostically useful metabolites in urine. The concentrations of phenylalanine and phenylacetic acid for five urine samples from patients with phenylketonuria were 347 +/- 177 and 282 +/- 224 microM/mM creatinine, respectively. The concentrations of tyrosine and 4-hydroxyphenyllactic acid in the urine of a patient with tyrosinemia were 112 and 1871 microM/mM creatinine, respectively.

Acidosis↗
PubMed1992

Superoxide formed from cigarette smoke impairs polymorphonuclear leukocyte active oxygen generation activity.

Reactive free radicals contained in cigarette smoke (CS) and compromised phagocytic antimicrobial activities including those of polymorphonuclear leukocytes (PMNs) have been implicated in the pathogenesis of severe CS-related pulmonary disorders. In CS-exposed buffer solutions, O2-. was the predominant generated reactive oxygen species, as demonstrated by lucigenin-amplified chemiluminescence and electron spin resonance (ESR) spin-trapping with 5,5-dimethyl-1-pyrroline N-oxide (DMPO). When PMNs were incubated in this buffer, phorbol 12-myristate 13-acetate (PMA)-stimulated active oxygen production and coupled O2 consumption were strongly impaired without appreciably affecting PMN viability (1-min exposure inhibited active oxygen production by 75%). Superoxide dismutase (SOD) totally protected and an iron chelator, diethylenetriaminepentaacetic acid (DETAPAC), also protected the CS-exposed PMNs, suggesting that generated O2-. was an initiating factor in the impairment and OH. generation was a subsequent injurious factor. Pretreatment of PMNs with antioxidants such as alpha-tocopherol and dihydrolipoic acid (DHLA) was partially protective. The results suggest that (i) O2-. is probably generated in the upper and lower respiratory tract lining fluid when they come in contact with CS; (ii) such generated O2-. can primarily impair PMN capabilities to generate reactive oxygen species; and (iii) since these effects may contribute to the pathogenesis of CS-related lung diseases, prior supplementation with antioxidants such as alpha-tocopherol or DHLA might be successful in preventing these deleterious effects.

Animals↗
PubMed1992

p33, an endogenous target protein for arginine-specific ADP-ribosyltransferase in chicken polymorphonuclear leukocytes, is highly homologous to mim-1 protein (myb-induced myeloid protein-1).

We have determined the partial amino acid sequence of p33, an endogenous substrate protein for arginine-specific ADP-ribosyltransferase in chicken polymorphonuclear leukocytes (heterophils), and found that the sequence was completely identical with the regions of amino acid sequences deduced from mim-1 (named for myb-induced myeloid protein-1, which is expressed in chicken promyelocytes) cDNA [(1989) Cell, 59, 1115-1125], except for one amino acid difference (Tyr297-->Ile). These results together with data on cellular and subcellular distributions of p33 in heterophils suggest that mim-1 may encode the precursor protein of p33.

ADP Ribose Transferases↗
PubMed1992

Antiradical effects in L-propionyl carnitine protection of the heart against ischemia-reperfusion injury: the possible role of iron chelation.

L-Propionyl carnitine has been shown to improve the heart's mechanical recovery and other metabolic parameters after ischemia-reperfusion. However, the mechanism of protection is unknown. The two dominating hypotheses are: (i) L-propionyl carnitine can serve as an energy source for heart muscle cells by being enzymatically converted to propionyl-CoA and subsequently utilized in the Krebs cycle (a metabolic hypothesis), and (ii) it can act as an antiradical agent, protecting myocardial cells from oxidative damage (a free radical hypothesis). To test the two possible pathways, we compared the protection afforded to the ischemia-reperfused hearts by L-propionyl carnitine and its optical isomer, D-propionyl carnitine. The latter cannot be enzymatically utilized as an energy source. The Langendorff perfusion technique was used and the hearts were subjected to 40 min of ischemia and 20 min of reperfusion. In analysis of ischemia-reperfused hearts, a strong correlation was found between the recovery of mechanical function and the presence of protein oxidation products (protein carbonyls). Both propionyl carnitines efficiently prevented protein oxidation but L-propionyl carnitine-perfused hearts had two times greater left ventricular developed pressure. The results indicate that both metabolic and antiradical pathway are involved in the protective mechanism of L-propionyl carnitine. To obtain a better insight of the antiradical mechanism of L-propionyl carnitine, we compared the ability of L- and D-propionyl carnitines, L-carnitine, and deferoxamine to interact with: (i) peroxyl radicals, (ii) oxygen radicals, and (iii) iron. We found that none of the carnitine derivatives were able to scavenge peroxyl radicals or superoxide radicals. L- and D-propionyl carnitine and deferoxamine (not L-carnitine) suppressed hydroxyl radical production in the Fenton system, probably by chelating the iron required for the generation of hydroxyl radicals. We suggest that L-propionyl carnitine protects the heart by a dual mechanism: it is an efficient fuel source and an antiradical agent.

Animals↗
PubMed1992

Antiinflammatory and analgesic activity of a non-peptide substance P receptor antagonist.

CP-96,345, a potent non-peptide antagonist of the substance P (SP) receptor, inhibited SP-, neurokinin A (NKA)- and neurokinin B-induced plasma extravasation in guinea pig dorsal skin. The inhibition was specific for the three tachykinins; CP-96,345 was not active against plasma leakage caused by histamine, bradykinin, platelet-activating factor or leukotriene D4. CP-96,345 inhibited capsaicin-induced plasma extravasation in the ureter, an inflammatory response caused by neuropeptides released from afferent C-fibers. Thus, the NK1 receptor appears to play a major role in vascular permeability increases induced by exogenous and endogenous tachykinins. In contrast, CP-96,345 was inactive against SP- and NKA-induced contraction of guinea pig ureter, suggesting that the smooth muscle contraction is not NK1-mediated. CP-96,345 exhibited analgesic activity in acetic acid-induced abdominal stretching in mice, indicating for the first time that SP plays a critical role in this model. The results of these studies support a pathophysiological role of SP and NK1 receptor under acute neurogenic inflammatory conditions and in pain.

Analgesics↗
PubMed1992

Cigarette smoke exposure increases the cell water organization and membrane order of cultured T cells.

In order to determine the effects of cigarette smoke (CS) exposure on the physical properties of cells, NMR water-proton relaxation time (which measures the intracellular water organization) and ESR spin labeling (which measures membrane order) measurements were performed on cultured Jurkat T cells exposed to CS. NMR spin-lattice relaxation time (T1) decreased with CS exposure in a dose-dependent fashion. A significantly depressed T1 value was obtained even when CS was delivered through a filter. Cell viability was not affected in this condition. Superoxide dismutase (SOD) prevented the depression of T1 value. These results suggest that superoxide radicals or subsequently generated species contained in the gas phase of CS increase the intracellular water organization in viable cells. CS exposure also increased the ESR membrane order parameter of nitroxide spin label. These physical characteristic changes may be important in CS-induced cell responses and cytopathology.

Cell Membrane↗
PubMed1992

Inhibitory effect of noradrenaline on acute liver injury induced by carbon tetrachloride in the rat.

The effect of exogenous noradrenaline (NA) on acute liver injury was investigated in rats receiving a single dose of carbon tetrachloride (CCl4). Animals were divided into the following groups: (I) no treatment, used for plasma catecholamine assay; (II) received CCl4 only; (III) treated with CCl4 plus noradrenaline (NA). Plasma levels of catecholamine (CA) were elevated in both groups II and III, particularly in NA: average value at 33 h after the exposure of CCl4 increased to 290-fold of the control in group II and to 513-fold in group III. Subsequently, the levels of NA decreased with time, and were comparatively well-preserved in the rats of group III. Hepatic changes observed in the animals of group II were as follows: destruction with reduced number in rough endoplasmic reticulum; destruction and disappearance of cristae in mitochondria, and numerous fat droplets (shown by electron microscopy); histologically observed marked centrilobular necrosis with steatosis followed by progression with time; and microangiographically demonstrated deranged intrahepatic microvasculature. By contrast, these changes were successfully prevented by NA treatment (group III). Furthermore, histologically observed centrilobular change was restored with time. It was concluded that, in a deranged state, NA takes a form quite dissimilar to ordinary state: Na exerts for hapatoprotective and is highly involved in liver injury.

Animals↗
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

ADP-ribosylation of actins by arginine-specific ADP-ribosyltransferase purified from chicken heterophils.

We reported the purification and characterization of an arginine-specific ADP-ribosyltransferase and acceptor protein p33 in granules of chicken peripheral polymorphonuclear leukocytes (heterophils) [Mishima, K., Terashima, M., Obara, S., Yamada, K., Imai, K. & Shimoyama, M. (1991) J. Biochem. (Tokyo) 110, 388-394]. In the present study, we obtained evidence that chicken non-muscle beta/gamma-actin, skeletal muscle alpha-actin and smooth-muscle gamma-actin were ADP ribosylated by the heterophil ADP-ribosyltransferase. The stoichiometry of ADP-ribose incorporation into these actins was 1.2 mol, 1.0 mol and 2.0 mol ADP-ribose/mol of beta/gamma-actin, alpha-actin and gamma-actin, respectively. The optimal pH for the ADP ribosylation was at pH 8.5, with the respective actin. Km values for NAD were calculated to be 30 microM with beta/gamma-actin, 35 microM with alpha-actin and 20 microM with gamma-actin. The Km values for the actin isoforms were 15 microM for beta/gamma-actin, 2.5 microM for alpha-actin and 10 microM for gamma-actin. ADP ribosylation of actin inhibited its capacity to polymerize, as determined by the increase in fluorescence intensity with N-(1-pyrenyl)iodoacetamide-labelled actin. Filamentous actin (F-actin) polymerized with the respective actin isoform was also ADP ribosylated, although the extent of the modification of F-actin was lower than that of globular actin (G-actin). In situ ADP ribosylation of beta/gamma-actin was evidenced with chicken peripheral heterophils permeabilized with saponin. Thus, the endogenous ADP ribosylation of actin in the heterophils may be involved in the cellular processes such as phagocytosis, secretion and migration.

Actins↗
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

Cerebral blood flow and histopathological changes following permanent bilateral carotid artery ligation in Wistar rats.

Cerebral blood flow and histopathological changes after bilateral carotid artery ligation (BCAL) in Wistar rats were studied. Eight of the 38 rats (21%) died within one week. In the 30 survivors, the incidence of histopathological change was 90% in the caudate nucleus, 23% in the cortex, 30% in the hippocampus, and 0% in the other structures. Local cerebral blood flow (LCBF) was measured using the quantitative autoradiographic 14C-iodoantipyrine technique in 24 anatomically discrete regions of the brain. BCAL induced ischemia in the entire forebrain. The percent reduction of LCBF was between 25-94% of the control at 2.5 h after BCAL. LCBF tended to recover 1 week after BCAL except for the regions of neuronal damage. These results suggest that neuronal damage does not correlate with the flow rate. In the present study, selective neuronal damage was also observed in rats with chronic cerebral ischemia.

Animals↗
PubMed1992

Tissue-type plasminogen activator of colonic mucosa in ulcerative colitis. Evidence of endothelium-derived fibrinolytic activation.

Microvascular endothelial alterations are thought to be a crucial step for development of hemorrhagic changes in various pathological states. In this study, we determined the activity and amount of tissue-type plasminogen activator (t-PA) in the biopsy specimens from sigmoid colon of patients with ulcerative colitis to evaluate endothelial alterations and vascular changes of permeability. The results of this investigation revealed that mucosal amount of t-PA in the active stage of ulcerative colitis was two- to threefold higher than in healthy controls, while t-PA levels in plasma samples showed no remarkable differences among the groups. Increased t-PA activity appeared to correlate well to the degree of inflammation of colonic mucosa, and t-PA amount was still increased in the inactive stage. The present study indicates that t-PA determination in colonic biopsy specimens may be useful for the evaluation of clinical activity of ulcerative colitis in terms of the mucosal microvascular endothelial changes.

Adult↗
PubMed1992

Teratogenicity of arotinoids (retinoids) in the rat whole embryo culture.

Structural modifications of the arotinoid molecule RO 13-7410 led to a difference in the teratogenic potencies of more than five orders of magnitude in mice in vivo and in micromass cultures of rat embryonic limb bud cells (Kistler et al. 1990). Five of these retinoids were selected and tested in rat whole embryo culture to determine the suitability of this in vitro test system for the identification of potentially non-teratogenic derivatives among this class of chemicals. The highest concentrations of the compounds with no effects (NOAEL) on general conceptus growth, on differentiation and on the frequency of dysmorphogenic embryos in vitro were compared with the lowest effective teratogenic doses in vivo (LOAEL) or with the concentrations leading to 50% inhibition of limb bud cell differentiation (IC50) in vitro. NOAEL's for the parameters of conceptus development ranged from 10(-5) micrograms/ml (0.03 nM) to 10 micrograms/ml (28.7 microM) for the compounds tested. These correlated very well with LOAEL and IC50 (R greater than 0.95). The types of dysmorphogenesis in vitro were those typical for retinoids, and for the most part resembled the malformations found in vivo. We conclude that the whole embryo culture system is a useful tool for the preliminary testing of retinoids.

Abnormalities, Drug-Induced↗
PubMed1992

Effect of rat CINC/gro, a member of the interleukin-8 family, on leukocytes in microcirculation of the rat mesentery.

Rat cytokine-induced neutrophil chemoattractant (CINC) is a member of the IL-8 family, and its human counterpart is gro/MGSA but not IL-8. We ascertained that chemically synthesized CINC was comparable to native CINC/gro with regard to chemotactic activity for rat neutrophils and studied the effect of synthesized CINC/gro on circulating leukocytes in microvascular vessels of rat mesentery. Exposure of rat mesentery to 10(-8)M authentic CINC/gro induced neutrophil adherence to and extravasation from postcapillary venules (PCVs) but not from capillaries or arterioles. CINC/gro concentrations as low as 10(-10) M were effective in causing neutrophil adherence. Neutrophils adhered to thin PCVs (mean diameter, approximately 25 microns) after exposure to CINC/gro for 15 min. The mean diameters of the PCV with adherence of neutrophils after exposure to CINC/gro for 30 and 60 min were 37 and 43 microns, respectively. The diameters of PCV with extravasation of neutrophils also increased in a time-dependent manner. The starting position of adherence of neutrophils was approximately 25-50 microns away from the upper junction of two vessels and remained virtually unchanged during exposure to CINC/gro for 60 min. However, the distance from the start to the end of neutrophil adherence increased in a time-dependent manner. The effect of CINC/gro on adherence and extravasation of leukocytes was neutrophil specific since other leukocytes such as lymphocytes and monocytes were not identified among the adherent and extravasated leukocytes.

Animals↗
PubMed1992

Early midzonal oxidative stress preceding cell death in hypoperfused rat liver.

Intralobular heterogeneity of oxidative stress and its topographic relationship with cell death during low-flow hypoxia were shown in perfused rat liver by digital microfluorography using dichlorofluorescin diacetate, a fluorochrome sensitive to intracellular hydroperoxide formation, and propidium iodide, which labels the nuclei of nonviable cells. The surface of the liver loaded with two precursors was microscopically visualized, and the fluorescence of dichlorofluorescein, a highly fluorescent molecule generated by hydroperoxide-mediated dichlorofluorescin oxidation, was digitally processed. Dichlorofluorescein fluorescence significantly increased in midzonal regions as early as 20 minutes after starting the 25% low-flow hypoxia. At 40 minutes the fluorograph showed multiple dotted patterns, and the intensity peaked at 60 minutes. The onset of cell death studied by propidium iodide was observed at 40 minutes, and its topographic distribution corresponded to the dichlorofluorescein-enhanced midzonal regions. Allopurinol diminished the early midzonal oxidative stress and retarded the onset of cell death. The current findings show that xanthine oxidase-dependent oxidative stress and the resultant cell death during low-flow hypoxia are spatially restricted in the intermediate zone between the periportal and pericentral regions.

Animals↗
PubMed1992

Integrated information-processing system in clinical orthodontics: an approach with use of a computer network system.

A computer network system has been developed in the Orthodontic Clinic, Osaka University Dental Hospital, to improve treatment efficiency and patient service. The system consists of a 32-bit host computer, its peripheral units, and personal computers connected to the host computer by data-transmission circuits, making up a local area network (LAN). It is possible in this system to integrate various types of data, such as the patient's basic information, treatment records, image data, and diagnostic analysis results to construct a relational database. It has been shown that the computer system developed in the orthodontic clinic has various clinical advantages.

Databases, Factual↗