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Biomedical subjects

M Tsuchiya

Publications and source records attributed to M Tsuchiya.

At least 73 records · Page 4Linked to original sources
PubMed1998

Suppression of cell adhesion and spreading activities of fibronectin by arginine-specific ADP-ribosyltransferase from chicken polymorphonuclear leukocytes.

Arginine-specific ADP-ribosyltransferase present in secretory granules of chicken polymorphonuclear leukocytes (so-called heterophils) was shown to be released into the extracellular space by secretagogues (Terashima et al., J. Biochem. 120 (1996) 1209-1215). In the present work, we examined fibronectin as an extracellular target protein of the released transferase. Fibronectin was ADP-ribosylated by purified transferase and stoichiometry of ADP-ribose incorporation into fibronectin was 1.0 mol/mol of fibronectin. Cell adhesion and spreading assays revealed that ADP-ribosylation of fibronectin markedly inhibited the adhesion activity of fibronectin. A proteolytic peptide map of ADP-ribosylated fibronectin demonstrated that the modification occurs in the cell binding domain of fibronectin. ADP-ribosylation of the RGD peptide suggests that the RGD sequence is the modification site in the domain. ADP-ribosylation of fibronectin in plasma means that fibronectin can probably serve as the substrate for extracellularly released ADP-ribosyltransferase in vivo. Thus, in the extracellular space, ADP-ribosyltransferase released from polymorphonuclear leukocytes may perhaps be involved in regulation of cell adhesion process by interfering with the activity of fibronectin.

ADP Ribose Transferases↗
PubMed1998

Inhibition of inducible nitric oxide synthase delays gastric ulcer healing in the rat.

We sought to clarify the role of nitric oxide (NO) generated from inducible NO synthase (iNOS) during healing of rat gastric ulcers. After gastric ulcers were induced by acetic acid, rats were treated with vehicle, N(G)-nitro-L-arginine methyl ester (L-NAME), aminoguanidine (AG), and dexamethasone (Dex) by gastric intubation twice a day for 3 days to 1 week. L-NAME significantly delayed healing compared with vehicle. AG and Dex significantly reduced ulcer size 3 days after ulcer induction but did not further reduce ulcer size 1 week after induction. iNOS expression was present in inflammatory cells, some epithelial cells, and in vascular smooth muscle in the regenerating mucosa of the vehicle-treated group. However, the number of iNOS-positive inflammatory cells increased in the AG- and L-NAME-treated groups. AG and L-NAME significantly increased the number of inflammatory cells with endogenous peroxidase and significantly reduced the number of apoptotic inflammatory cells compared with vehicle. In conclusion, inhibition of iNOS increases the number of inflammatory cells in the ulcer margin and delays ulcer healing. These observations suggest that NO generated from iNOS not only participates in ulcer formation but also plays a beneficial role in ulcer healing, in part by the exclusion of iNOS-positive inflammatory cells from the regenerating mucosa.

Animals↗
PubMed1998

In vitro study on antioxidant potential of various drugs used in the perioperative period.

BACKGROUND: Since surgical trauma not only intensifies the oxidative stress by generating reactive oxygen species (ROS), but also weakens the biological defense system against ROS attack, the antioxidant activity of drugs used during the perioperative period, which possibly normalizes the impaired redox state in the patient, is of fundamental importance and great clinical interest. METHODS: We have applied the phycoerythrin fluorescence-based assay, in which 2,2'-azobis (2-amidinopropane) dihydrochloride (AAPH)-generated peroxyl radical attacks B-phycoerythrin (B-PE) to lead to a sensitive decrease in its fluorescence intensity linearly, to evaluate the antioxidant activity of major drugs in anesthetic practice. RESULTS: By the protective effect on B-PE fluorescence decay, the antioxidant activities of the drugs were classified into three groups: Group I drugs, which only slowed B-PE fluorescence decay (nicardipine, verapamil, diltiazem, ephedrine, aminophylline, vecuronium, lidocaine, mepivacaine, midazolam, thiamylal, droperidol, ketamine, hydroxyzine, butorphanol, prednisolone, hydrocortisone, betamethasone, dexamethasone, methylprednisolone, and furosemide); Group II drugs, which protected B-PE oxidation completely and stopped fluorescence decay in a certain duration (dopamine, epinephrine, norepinephrine, dobutamine, isoproterenol, and buprenorphine); and Group III drugs, which had no protective effect on B-PE oxidation (nitroglycerin, prostaglandin E1, neostigmine, pancuronium, suxamethonium, atropine, bupivacaine, pentazocine, and heparin). CONCLUSION: These results indicate that Group I and II drugs exert some antioxidant activity in vitro, as measured by their protection of fluorescence decay of B-PE. Careful consideration of these properties might, then, serve to facilitate more efficient drug application.

Adjuvants, Anesthesia↗
PubMed1998

Discrimination of alpha1-adrenoceptor subtypes in rat aorta and prostate.

This study was designed to further discriminate alpha1-adrenoceptor subtypes in rat aorta and prostate using functional experiments. Responses induced by phenylephrine were equilibrated in both tissues. The pA2 values and slope factors of several alpha1-antagonists were assessed using concentration-response curves. The antagonists used were prazosin, WB-4101, 5-methylurapidil (5-MU), HV-723, and tamsulosin. In addition, the effects of chloroethylclonidine (CEC) and nifedipine on phenylephrine-induced contractions were investigated. A high pA2 value for prazosin was observed in both tissues (aorta 9.84, prostate 9.19) and the ranking of each drug's pA2 value is as follows: tamsulosin > prazosin > WB-4101 > HV-723 > 5-MU in the aorta, and tamsulosin > prazosin > 5-MU > WB-4101 = HV-723 in the prostate. A significant difference between the pA2 value of each drug except for tamsulosin in the aorta and in prostate was observed (p < 0.01). Inhibition of contraction by pretreatment with CEC was 83.9 +/- 2.42% in the aorta, and 6.17 +/- 0.94% in the prostate. On the other hand, inhibition of maximal response by pretreatment with nifedipine (1 micromol/l) was 35.1 +/- 2.2% in the aorta and 24.5 +/- 3.1% in the prostate. A good correlation between these pA2 values and pKi values for recombinant human alpha1b-adrenoceptor expressed in CHO cells (aorta) and alpha1a-subtypes of CEC pretreated rat hippocampus (prostate) were observed. In conclusion, these results suggest that: (1) the contraction of these two tissues is mediated by alpha1H-adrenoceptor with a high affinity for prazosin; (2) alpha1H-adrenoceptors correspond to alpha1b-(aorta) and alpha1a-subtypes (prostate), and (3) each alpha1-adrenoceptor subtype in the aorta and prostate may be alpha1b-(aorta) and alpha1a-subtypes (prostate), respectively.

Acetonitriles↗
PubMed1998

Expression and effect of adrenomedullin on rat granulosa cell.

Adrenomedullin (AM) is a potent hypotensive peptide recently discovered in extracts of human pheochromocytoma. To elucidate the regulation of AM production in the ovary, the effect of gonadotropin on the production of AM was studied in the cultured rat granulosa cells. A Northern blot analysis of the LH receptor and adrenomedullin yielded a major hybridizing band at 5.4 kb and 1.6 kb, respectively. In our culture system of rat granulosa cells, without any stimulus, the LH receptor mRNA was undetectable and the AM mRNA level was stably expressed for 6 days. FSH significantly induced LH receptor mRNA and suppressed AM mRNA for 4 days of culture and with the addition of hCG after 2 days of pretreatment with FSH, AM mRNA levels were markedly suppressed. FSH and 8-Br-cAMP significantly increase LH receptor mRNA and suppress AM mRNA in a dose-dependent manner. These data indicated that the differentiation of granulosa cells mediated by gonadotropins were associated by suppression in AM expression through a cAMP-dependent mechanism. On the other hand, AM stimulated a rapid rise in intracellular cAMP levels, which peaked within 15 min of addition, in a dose-dependent manner with a maximal response seen at 100 nM. Additionally, AM enhanced the effects of FSH, acting additionally to produce cAMP in the cells. AM may play a role in the process of granulosa cell differentiation as a local regulator through an autocrine/paracrine mechanism.

8-Bromo Cyclic Adenosine Monophosphate↗
PubMed1998

Rapid diagnosis of oral tuberculosis by amplification of Mycobacterium DNA from paraffin embedded specimens.

The polymerase chain reaction (PCR) assay is a powerful tool for quick diagnosis of various infectious diseases. We applied this technique as well as conventional histopathological examination to diagnose oral tuberculosis. Ziehl-Neelsen staining of oral mucosal specimens often fails to detect Mycobacterium (M.) tuberculosis due to the low number of bacteria in the tissue. Specific primers and probes were synthesized based upon the nucleotide sequence of the 65 kDa membrane protein of M. tuberculosis. DNA extracted from the paraffin-embedded tissue was amplified using taq polymerase. PCR assay detected M. tuberculosis in 5 of 6 samples. Although the gene segments from these species were quite similar, the gamma 32P labeled noligonucleotide probes distinguished between M. tuberculosis and M. fotuitum by southern blot hybridization. In all specimens that were Ziehl-Neelsen negative, M. tuberculosis DNA was detected by PCR. These results suggest that PCR is a useful means of diagnosing mycobacterium infection.

Adult↗
PubMed1998

[The relationship between respiratory function and the change in end-tidal nitrous oxide concentration].

The aim of the present study is to clarify the relationship between respiratory function and the rate of change in alveolar anesthetic concentration. We measured the concentration of end-tidal nitrous oxide (N2O) when 50% N2O was administered to 15 patients of ASA I possessing normal respiratory function during the course of propofol-100% oxygen anesthesia. All patients were ventilated at a rate of 8-10 ml.kg-1 x 8 times per minute using a conventional anesthetic ventilator with semi-closed circuit and 4 l.min-1 inflow of fresh gas. Arterial CO2 partial pressure was maintained at 36.2 +/- 1.8 mmHg and no significant circulatory change was observed while N2O was administered. The rate of increase of end-tidal N2O concentration in poor FEV1.0/FVC% group was significantly slower than that in high FEV1.0/FVC% group, while there was no relation between %VC and the end-tidal N2O concentration change. Since N2O is an inhaled anesthetic, it is well considered that the effect of FEV1.0/FVC% may be observed in other inhaled anesthetic although the magnitude of the effect may vary. The present result suggests that respiratory function, especially FEV1.0/FVC%, is an important factor affecting the rate of change in alveolar anesthetic concentration and, in lower FEV1.0/FVC% group, it takes more time to achieve the intended alveolar concentration.

Aged↗
PubMed1997

ADP-ribosylation of tuftsin suppresses its receptor-binding capacity and phagocytosis-stimulating activity to murine peritoneal macrophages.

Arginine-specific ADP-ribosyltransferase present in granules of chicken polymorphonuclear leukocytes (so-called heterophils) is released into the extracellular space by stimulus of calcium ionophore A23187 or opsonized zymosan [Terashima et al. (1996) J. Biochem. 120, 1209-1215]. In the present work, we examined extracellular targets of the released transferase and identified tuftsin, a phagocytosis-stimulating tetrapeptide derived from leukokinin, as a preferential substrate of the enzyme in chicken plasma. Specific binding of FITC-tuftsin to murine peritoneal macrophages, observed under a fluorescent microscope, was impaired by ADP-ribosylation of the labelled peptide. Phagocytic assay analyzed by flow cytometry revealed that ADP-ribosylation of tuftsin decreased its phagocytosis-stimulating activity towards the macrophages. Thus, the ADP-ribosylation of tuftsin apparently decreases its biological activity and ADP-ribosylation may possibly be involved in inflammatory processes through alterations in tuftsin activity.

Adenosine Diphosphate Ribose↗
PubMed1997

Immunohistochemical localization of ADP-ribosylarginine hydrolase in rodent CNS.

Polyclonal antibodies were generated against ADP-ribosylarginine hydrolase (AAH), using recombinant fusion protein of rat AAH and glutathione-S-transferase as a immunogen, and affinity-purified. Western blotting showed that the antibodies recognized in mouse brain homogenate a single protein with a molecular mass of 38 kDa, the expected size for mouse AAH. An analysis using the antibodies revealed that heavy labelings were apparent in various brain regions. In the cerebral cortex, pyramidal cells in layers III and V were the most heavily labeled. In the hippocampal formation, labeling was present on the pyramidal neurons and granule cells. The most heavily immunostained cell type was the pyramidal neuron of CA3. In the cerebellum, Purkinje cells were the most heavily labeled. Less intense staining was present over the granule cells. In the basal ganglia, neurons in the caudate nucleus and large multipolar cells in the amygdaloid complex were immunoreactive. Heavy labeling was seen in many midbrain and brainstem nuclei. Neurons in the habenula and ependymal cells were stained heavily. On Western blot analysis of rat cerebrospinal fluid (CSF), the anti-AAH antibodies recognized a protein with a molecular mass of 38 kDa. This is apparently the first evidence of a widespread but distinctive distribution of AAH in neurons of mouse brain and the presence of extracellular AAH in rat CSF.

Animals↗
PubMed1997

Molecular cloning and characterization of arginine-specific ADP-ribosyltransferases from chicken bone marrow cells.

Among a number of tissues and peripheral blood cells in chicken, leukocytes, bone marrow cells, liver and spleen showed high ADP-ribosyltransferase activity, with leukocytes having the highest. Density gradient centrifugation of the leukocytes revealed that the leukocyte ADP-ribosyltransferase originates in the polymorphonuclear cells, so called heterophils. Subcellular distribution of the cells showed the localization of the enzyme in the granule fraction. Based on the obtained amino acid sequences of arginine-specific ADP-ribosyltransferase purified from chicken peripheral heterophils, two arginine-specific ADP-ribosyltransferase cDNAs (designated AT1 and AT2) were obtained from chicken bone marrow cells. Each cDNA encodes a different peptide of 312 amino acid residues. Homology of the deduced amino acid sequences between AT1 and AT2 was 78.3%. Arginine-specific ADP-ribosyltransferase activity was detected in culture medium of COS 7 cells transiently transfected with AT1 cDNA, while activity from the cells transfected with AT2 cDNA was found in both culture medium and cell lysate. AT1 transferase required 2-mercaptoethanol (MSH) for the activity and in the presence of NaCl, the activity was inhibited while the AT2 enzyme was activated by either agent. Highly conserved regions were observed among the deduced amino acid sequences of AT1, AT2, chicken erythroblast and rabbit and human skeletal muscle ADP-ribosyltransferases, and rodent T-cell surface antigen RT6. Two forms of the transferase with much the same properties as AT1 and AT2 proteins, regarding the effect of NaCl and MSH, were detected in bone marrow cells. Based on these results it seems that AT1 and AT2 cDNAs encode the two forms of arginine-specific ADP-ribosyltransferase detected in chicken bone marrow cells.

ADP Ribose Transferases↗
PubMed1997

A newly identified glycosylphosphatidylinositol-anchored arginine-specific ADP-ribosyltransferase in chicken spleen.

An arginine-specific ADP-ribosyltransferase activity was detected in chicken spleen membrane fraction using a capillary electrophoresis assay and the activity was extracted by phosphatidylinositol-specific phospholipase C but not by 1 M NaCl or 1% Triton X-100. The enzyme protein was purified from chicken spleen membrane fraction to apparent homogeneity with a six-step method containing phosphatidylinositol-specific phospholipase C treatment, ammonium sulfate precipitation and conventional column chromatographies. Apparent molecular mass of the purified enzyme estimated with SDS/PAGE was 44 kDa. N-glycanase treatment of the enzyme reduced the apparent molecular size on SDS/PAGE. The enzyme was recognized by anti-cross reacting determinant antibodies. Partial amino acid sequence of the purified enzyme protein showed high homologies with primary structures of previously reported chicken arginine-specific ADP-ribosyltransferases.

ADP Ribose Transferases↗
PubMed1997

GTP-dependent modification of a 21-kDa substrate with NAD+ in bovine brain soluble fraction is not ADP-ribosylation of small G-protein but tailing of tRNA.

Labeling of 21-kDa material was observed when bovine brain soluble fraction was incubated with [adenylate-32P]NAD+ in the presence of GTP. The 21-kDa substrate, slightly smaller than C3 substrate in size, was labeled even without C3 exoenzyme. GTP could be replaced by nucleoside triphosphates other than ATP while ATP inhibited the GTP-induced labeling of 21-kDa substrate. After incubation of the soluble fraction with [adenylate-32P]NAD+ in the presence of GTP, [32P]ADP and [32P]ATP were detected in addition to [32P]AMP and [32P]ADP-ribose while only the last two nucleotides were observed without GTP. The 21-kDa substrate was labeled with [alpha-32P]ATP even in the absence of GTP, suggesting adenylylation rather than ADP-ribosylation. The labeled 21-kDa substrate, was extractable by phenol, disappeared with RNase treatment but not with tryptic digestion. Alkaline treatment of the phenol extract yielded an equal mixture of 3'-[32P]CMP and 2'-[32P]CMP. From these results we concluded that the 21-kDa labeling is a result of tRNA tailing with [alpha-32P]ATP generated from the [32P]AMP moiety of [adenylate-32P]NAD+. Results from reconstitution experiments using enzymes and tRNA purified from bovine brain soluble fraction, which are involved in this pathway, confirmed our conclusion.

ADP Ribose Transferases↗
PubMed1997

The serum factor from patients with ulcerative colitis that induces T cell proliferation in the mouse thymus is interleukin-7.

The disturbance of immune regulatory T cells is related to the pathogenesis of ulcerative colitis. Here we demonstrated and characterized the serum factor from ulcerative colitis patients that induced proliferation of intrathymic T cells. The factor isolated from the patient sera by a combination of gel filtration and anion-exchange chromatography induced proliferation of CD4+CD8- intrathymic T cells in the organ-cultured embryonic mouse thymus. Purification and amino acid sequence analysis of the serum factor demonstrated that the N-terminal 12 sequence was homologous to that of interleukin-7. SDS-PAGE and Western blot confirmed that purified serum factor was interleukin-7. Enzyme immunoassay demonstrated that the serum interleukin-7 concentration was significantly increased in the patients. PCR and Southern blot hybridization demonstrated that interleukin-7 mRNA expression was increased in the thymus tissues from patients but decreased in the colonic mucosa. Since interleukin-7 is a crucial cytokine for proliferation and differentiation of T cells in the thymus, the present study indicates that interleukin-7 may contribute to the disturbance of immune regulatory T cells in ulcerative colitis.

Amino Acid Sequence↗
PubMed1997

Nitric oxide-induced modification of glyceraldehyde-3-phosphate dehydrogenase with NAD+ is not ADP-ribosylation.

One biological effect of nitric oxide (NO) has been believed to be exerted through induction of the ADP-ribosyltransferase activity of glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Though this notion is based on the finding that NO increases the auto-ADP-ribosylation of GAPDH, controversial data have also been reported. To determine whether or not NO really activates ADP-ribosylation, we re-examined the NO-induced modification of GAPDH with NAD+. GAPDH was modified equally with [adenosine-14C]NAD+ and [carbonyl-14C]NAD+, indicating that the glycoside bond of NAD+ between ADP-ribose and nicotinamide is intact. The release of nicotinamide from NAD+ was not evident during incubation of GAPDH with [carbonyl-14C]NAD+. Thus, the modification of GAPDH is apparently not ADP-ribosylation. In addition, we found that basal and glyceraldehyde-3-phosphate-induced modifications of GAPDH, both of which have also been explained as ADP-ribosylation, were not ADP-ribosylation, and that the modification of GAPDH in the absence and presence of NO or GA3P was distinct in the dithiothreitol effect or resistance to HgCl2.

Adenosine Diphosphate Ribose↗
PubMed1997

Basic fibroblast growth factor increases constitutive nitric oxide synthase during healing of rat gastric ulcers.

The purpose of this study was to clarify the effect of basic fibroblast growth factor (bFGF) on nitric oxide (NO) synthesis during healing of rat gastric ulcers. After experimental gastric ulcers were induced by acetic acid, rats were treated with vehicle, recombinant human bFGF (CS23, 10 micrograms/kg) and NG-nitro-L-arginine methyl ester (L-NAME, 1 mg/kg), an NO synthase (NOS) inhibitor, through an orogastric tube twice daily for 3 days or 1 week. CS23 significantly reduced ulcer size, and L-NAME significantly delayed healing compared with the vehicle group and significantly inhibited the efficacy of CS23. Although constitutive NOS (cNOS) activity significantly decreased and inducible NOS (iNOS) activity significantly increased in the vehicle group, CS23 significantly inhibited these changes. cNOS immunoreactivity on the vessels and neurons disappeared in the vehicle group, and newly formed vessels as well as neurons were observed with positive endothelial and neuronal NOS immunoreactivity in the CS23-treated group. External administration of bFGF accelerated ulcer healing, with recovery of NO synthesis in both endothelial cells and neurons. These observations suggested that increased NO synthesis with angiogenesis and reinnervation has a beneficial effect on gastric ulcer healing.

Acetic Acid↗
PubMed1997

Susceptibility of experimental autoimmune hepatitis in transgenic mice overexpressing the c-H-ras gene.

Results from a recent study of ours have demonstrated the significant role of the wild-type ras gene in the development of hepatocellular carcinoma in rasH2 mice having prototype human c-H-ras genes. Chronic cell death and regeneration have been considered to work as co-carcinogens with wild-type ras gene overexpression in this model. To elucidate a role of gene overexpression in the occurrence of chronic inflammation, we tried to induce inflammation in the liver of rasH2 mice by immunizing them with the supernatant of a freshly prepared syngenic liver homogenate. Immunization resulted in a dense inflammatory infiltrate in the portal tract and focal necrosis with spots of fatty or foamy degeneration in the transgenic mouse liver; however, these observations were less frequently observed in non-transgenic mouse liver. Monocytes, granulocytes and plasma cell infiltration were observed in the livers of transgenic mice. An immunohistochemical study showed that CD3-positive lymphocytes also infiltrated the liver. The inflammatory infiltrate was still present in the transgenic liver 24 weeks after the last injection, but little infiltrate was observed at the same time in non-transgenic mice. No hepatic tumours could be produced over the 6 months duration of the study and the results are only preliminary. However, these results do suggest that overexpression of wild-type ras is partially responsible for the occurrence of autoimmune chronic hepatitis.

Animals↗
PubMed1997

Incidence of hypocomplementemia in elementary and junior high school children with urinary abnormalities.

Abnormalities were detected in 2669 of 326,257 elementary and junior high school children (169,856 males and 156,401 females) who were screened at school for urinary abnormalities. Serum complement (C3) level was measured in all 2669 children having urinary abnormalities (811 males, 1856 females). Three had a serum C3 level that was more than three standard deviations below the mean value. Type I membranoproliferative glomerulonephritis (MPGN) was diagnosed on histological examination in one of these three children, while the other two did not undergo renal biopsy because they had serum C3 levels of 40 and 44 mg/dL, respectively, and because their urinary abnormalities were transient. It was considered that there is not much significance in testing the serum complement in the urine screening done at school and the cost/benefit ratio is low. The results appeared to reflect the frequency of persistent hypocomplementemic MPGN in Japan in recent years.

Adolescent↗