M Shimamura

Tokyo Metropolitan Institute of Medical Science, Tokyo, Tokyo-to, Japan

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Publications (46)112.43 Total impact

  • Conference Proceeding: Verifying reliability interactions for the robot communication platform and contribution to the international standards
    M. Narita, K. Iwasa, M. Shimamura, T. Yamaguchi
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    ABSTRACT: The common robot communication platform and the robot services using Web Services are gaining acceptance. Since multi-vendor/multi-implementation environments are popular, a standard specification of these and their interoperability are critical requirements. Reliable messaging - one of the key technologies to deploy such Web Services based systems - has been standardized recently. However, interoperability/conformance for reliable messaging implementations is not well verified. This article describes (1) requirements of conformance and interoperability test suite for Web Services, and how we implemented the test suite satisfying these requirements, (2) the test results and the evaluation for reliable message implementations based on currently available two standards, using this test suite, (3) authors' contribution to the international standard body based on our test results.
    Soft Computing in Industrial Applications, 2008. SMCia '08. IEEE Conference on; 07/2008
  • Conference Proceeding: Interoperability verification for Web Service based robot communication platforms
    M. Narita, M. Shimamura, K. Iwasa, T. Yamaguchi
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    ABSTRACT: The common robot communication platform using Web service is well accepted and becoming popular gradually. One of the key components for robot communication platform is the reliable messaging which provides reliable high performance message transfer. Both conforming to standard specifications and interoperability among multiple implementations are critical requirements for the platform, because different robots and different services should be able to connect and communicate each other on the platform. However, there is no conformance/interoperability testing tool for the reliable message component of Web services. This paper describes requirements for the conformance and interoperability testing for Web service technologies, and how we developed the verification suit that satisfies the requirements by automated error case verification model. This paper also reports the interoperability verification results for the reliable message component of Web service. It shows that the verification suite is effective to verify interoperability easily even for various complicated error situation. And it is also shows the application driven tests, which neither require installation of the test programs nor probes, are effective to ensure the interoperability in the actual application system and the common robot service platform implementation.
    Robotics and Biomimetics, 2007. ROBIO 2007. IEEE International Conference on; 01/2008
  • Source
    Article: A novel hypoxia-dependent 2-nitroimidazole KIN-841 inhibits tumour-specific angiogenesis by blocking production of angiogenic factors.
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    ABSTRACT: Tumour angiogenesis is initiated by angiogenic factors that are produced in large amounts by hypoxic tumour cells. The inhibition of this step may lead to tumour-specific antiangiogenesis because normal tissues are not usually hypoxic. On the other hand, blocking a biological function of endothelial cells is known to result in angiogenic inhibition. To produce a tumour-specific and powerful antiangiogenesis, we determined whether potent angiogenic inhibition could be achieved by inhibiting the production of angiogenic factors by hypoxic tumour cells and simultaneously blocking certain angiogenic steps in endothelial cells under normoxia. We focused on the 2-nitroimidazole moiety, which is easily incorporated into hypoxic cells and exhibits its cytotoxicity as hypoxic cytotoxin. We designed and synthesised 2-nitroimidazole derivatives designated as KIN compounds, and investigated their antiangiogenic activities under normoxia using a chick embryo chorioallantoic membrane. KIN-841 (2-nitroimidazole 1-acetylhydroxamate) showed a potent angiogenic inhibition in a dose-dependent manner. This compound inhibited the proliferation of bovine pulmonary arterial endothelial (BPAE) cells more strongly than that of tumour cells, such as Lewis lung carcinoma (3LL) cells, under normoxia. The inhibition of cell proliferation by KIN-841 under hypoxia increased about five-fold compared to that under normoxia. Moreover, under hypoxia, KIN-841 significantly decreased the excessive production of vascular endothelial cell growth factors induced by 3LL cells as determined by tritium-labelled thymidine ([(3)H]thymidine) incorporation into BPAE cells and by ELISA. Intraperitoneal administration of KIN-841 suppressed 3LL-cell-induced in vivo angiogenesis in the mouse dorsal air sac system. These results indicate that the regulation of the production of angiogenic factors by hypoxic tumour cells is a useful target for tumour-specific angiogenesis inhibition, and that KIN-841, which causes simultaneous direct inhibition of endothelial cell function and production of angiogenic factors by hypoxic tumour cells, is a very potent inhibitor of tumour-specific angiogenesis. Thus, the potential for clinical use of KIN-841 as an antitumour drug is very high.
    British Journal of Cancer 02/2003; 88(2):307-13. · 5.04 Impact Factor
  • Article: Spinorphin as an endogenous inhibitor of enkephalin-degrading enzymes: roles in pain and inflammation.
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    ABSTRACT: It is possible that enkephalins are involved in the pain-modulating mechanism in the spinal cord. Enkephalins, however, are short-lived, being rapidly degraded by various endogenous enzymes. Many substances that inhibit enkephalin-degradation have been investigated and it has been reported that some inhibitors (e.g. kelatorphan and RB101) alone showed anti-nociceptive activity. We found an endogenous factor that modulated enkephalin-degrading activity and purified it from bovine spinal cord based on its inhibitory activity toward enkephalin-degrading enzymes. Structural analysis revealed the factor to be Leu-Val-Val-Tyr-Pro-Trp-Thr and it was named spinorphin. It has been found that spinorphin inhibited the activity toward various enkephalin-degrading enzymes from monkey brain, especially dipeptidyl peptidase III (DPPIII, Ki=5.1 x 10(-7) M). Recently we reported that this inhibitor significantly inhibited bradykinin (BK)-induced nociceptive flexor responses. Importantly, the mode of inhibition to BK-responses by spinorphin was different from the case with morphine. The morphine-induced blockade of BK-response was attenuated by pertussis toxin treatment, whereas that of spinorphin was not. We also have reported roles for spinorphin in inflammation. Spinorphin significantly inhibited the functions of polymorphonuclear neutrophils (PMNs) by suppressing the binding of fMLF to its receptor on PMNs. Further, this inhibitor suppressed the carrageenan-induced accumulation of PMN in mouse air pouches after intravenous administration. These results indicate that spinorphin may be an endogenous anti-inflammatory regulator. The possible role of spinorphin and its analog as regulators in pain and inflammation will be discussed.
    Current Protein and Peptide Science 01/2003; 3(6):587-99. · 2.89 Impact Factor
  • Article: Inhibition of angiogenesis by humulone, a bitter acid from beer hop.
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    ABSTRACT: On the basis of our previous finding that humulone, a bitter acid from beer hop extract, was a potent inhibitor of bone resorption and inhibited the catalytic activity of cyclooxygenase-2 (COX-2) and more potently the transcription of the COX-2 gene, we examined the effect of humulone on angiogenesis, using chick embryo chorioallantoic membranes (CAMs) and vascular endothelial and tumor cells. Humulone significantly prevented in vivo angiogenesis in CAM in a dose-dependent manner with an ED(50) of 1.5 microg/CAM. Humulone also inhibited in vitro tube formation of vascular endothelial cells. Moreover, it suppressed the proliferation of endothelial cells and the production of vascular endothelial growth factor (VEGF), an angiogenic growth factor, in endothelial and tumor cells. Thus, humulone is a potent angiogenic inhibitor, and may be a novel powerful tool for the therapy of various angiogenic diseases involving solid tumor growth and metastasis.
    Biochemical and Biophysical Research Communications 12/2001; 289(1):220-4. · 2.48 Impact Factor
  • Article: Characterization of tynorphin, a potent endogenous inhibitor of dipeptidyl peptidaseIII.
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    ABSTRACT: To find a more effective inhibitor than spinorphin (LVVYPWT), an endogenous factor derived from bovine spinal cord, we synthesized spinorphin analogues and assayed their inhibitory activity toward DPPIII among enkephalin-degrading enzymes. Tynorphin (VVYPW), an N-terminal and C-terminal truncated form of spinorphin, exhibited more potent inhibitory activity and an IC50 value of 0.086 +/- 0.05 microg/ml (n = 4), whereas structures smaller than four amino acid residues exhibited almost no or less activity, suggesting that a five amino acid structure containing a Tyr-Pro residue is essential for the inhibition. The inhibition of DPPIII by tynorphin was predominantly competitive and the Ki value was found to be 7. 50 +/- 1.19 x 10(-8) M on Lineweaver-Burk plotting. The inhibitory activity of tynorphin toward other enkephalin-degrading enzymes such as neutral endopeptidase, aminopeptidase, and angiotensin-converting enzyme was not as high as that toward DPPIII, suggesting that tynorphin is a specific inhibitor of DPPIII. In HPLC analysis, human serum cleaved tynorphin rapidly (38% of control at 2 h and background level at 4 h), but in the presence of leuhisitin, an aminopeptidase inhibitor, tynorphin was maintained at the original level for 24 h. These results indicated that tynorphin had a more effective structure for expression of inhibitory activity toward DPPIII.
    Peptides 05/2000; 21(4):503-8. · 2.43 Impact Factor
  • Article: The proteasome is involved in angiogenesis.
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    ABSTRACT: The proteasome is a recently identified intracellular protease whose catalytic active site is a threonine residue and has been shown to play key roles in a variety of important intracellular events, including cell cycle progression, the antigen-presenting pathway, and apoptosis. However, its biological significance in multicellular organisms is still largely unknown because of lack of experimental systems for its study. Here we verified potential involvement of the proteasome in angiogenesis using lactacystin, a specific proteasome inhibitor. Lactacystin treatment resulted in almost complete prevention of in vivo neovascularization in the developing chick embryo chorioallantoic membrane. It also inhibited vascular endothelial tube formation on Matrigel, a model for in vitro angiogenesis, in a concentration-dependent fashion. Moreover, it prevented production of plasminogen activator, an important protease responsible for induction of angiogenesis, by endothelial cells, which correlated well with its suppression of intracellular proteasome activity. Our studies suggest that the proteasome operates in the process of angiogenesis, a phenomenon essential in important physiological and pathological settings.
    Biochemical and Biophysical Research Communications 06/1998; 246(1):243-8. · 2.48 Impact Factor
  • Article: Inhibitory action of spinorphin, an endogenous regulator of enkephalin-degrading enzymes, on carrageenan-induced polymorphonuclear neutrophil accumulation in mouse air-pouches.
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    ABSTRACT: Whether spinorphin, an endogenous regulator of enkephalin-degrading enzymes, plays a role in an anti-inflammatory action was examined, using a mouse air-pouch assay as a model of acute inflammation. Repeated intravenous administration (6 times) of spinorphin every hour significantly suppressed carrageenan-induced polymorphonuclear neutrophil (PMN) accumulation, an indicator of inflammation (3.21+/-0.95 x 10[6] cells vs 8.92+/-0.96 x 10[6] cells, 10mg/kg spinorphin-treated vs saline-treated group, n=5, P<0.01) at 6 hr. The combination of spinorphin and leuhistin (2 mg/kg, i.v.), a specific inhibitor of aminopeptidase N (APN), markedly suppressed the PMN accumulation induced by carrageenan (1.11+/-0.17 x 10[6] cells, 88% inhibition compared to the saline-treated group, n=5, P<0.01). This inhibition was less than, but comparable to that of dexamethasone (30 mg/kg/one shot, i. v.), a representative anti-inflammatory drug. These results indicate that spinorphin may be an endogenous anti-inflammatory regulator, its inhibitory activity being modulated by APN.
    Life Sciences 01/1998; 62(19):1767-73. · 2.53 Impact Factor
  • Article: Inhibitory effects of spinorphin, a novel endogenous regulator, on chemotaxis, O2- generation, and exocytosis by N-formylmethionyl-leucyl-phenylalanine (FMLP)-stimulated neutrophils.
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    ABSTRACT: To characterize the inflammatory effect of spinorphin, an endogenous peptide purified from bovine spinal cord, its effects on chemotaxis, O2- generation, and exocytosis by N-formylmethionyl-leucyl-phenylalanine (FMLP)-stimulated human neutrophils (PMNs) in vitro were examined. At 10 microM, spinorphin significantly inhibited chemotaxis by FMLP-stimulated PMNs. Spinorphin at 100 microM also inhibited both O2- generation and exocytosis of beta-glucuronidase and collagenase by FMLP-stimulated PMNs. The mechanisms by which spinorphin inhibits these PMN functions were examined further. Spinorphin markedly suppressed the binding of FML[3H]P to its receptor on PMNs, as observed in a binding assay. However, other neuropeptides that were examined (angiotensin II and substance P) had no effect on FML[3H]P binding, suggesting the possibility that spinorphin plays a specific role in the inhibition of the binding between FMLP and its receptor. The suppression of FMLP binding also caused a decrease of the FMLP-induced intracellular calcium concentration [Ca2+]i, which acts as a second messenger leading to PMN functions. These results suggest that spinorphin may be a new endogenous inflammation-regulatory peptide that modulates the interaction of FMLP with its receptor.
    Biochemical Pharmacology 10/1997; 54(6):695-701. · 4.70 Impact Factor
  • Article: Design, synthesis, and biological activity of anti-angiogenic hypoxic cell radiosensitizer haloacetylcarbamoyl-2-nitroimidazoles.
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    ABSTRACT: We designed, synthesized, and evaluated haloacetylcarbamoyl-2-nitroimidazoles, including chloro (KIN-1800, TX-1835, and TX-1836) and bromo derivatives (TX-1844, TX-1845, and TX-1846), as potential hypoxic cell radiosensitizers with antiangiogenic activities. To establish biological function owing to the haloacetylcarbamoyl group in the side-chain, we compared their in vitro radiosensitizing activities with those of their parent 2-nitroimidazoles without haloacetylcarbamoyl groups: misonidazole (MISO), TX-1831, and TX-1832, respectively. Both tert-butoxy substituted derivatives. TX-1835 and TX-1845, were more potent radiosensitizers than TX-1831. The p-tert-butylphenoxy-substituted derivatives, TX-1836 and TX-1846, and the methoxysubstituted derivatives, KIN-1800 and TX-1844, were stronger radiosensitizers than TX-1832 and MISO. We examined the anti-angiogenic activities of these 2-nitroimidazole derivatives containing haloacetylcarbamoyl group by the rat lung endothelial (RLE) cell proliferation assay and chick embryo chorioallantoic membrane (chick CAM) angiogenesis assay and showed that haloacetylcarbamoyl-2-nitroimidazoles were more potent angiogenic inhibitors than the corresponding desacetylcarbamoyl-2-nitroimidazoles. The in vivo chick CAM angiogenesis assay showed that the strong bromoacetylcarbamoyl-2-nitroimidazole radiosensitizers, such as TX-1845 and TX-1846, were the strongest angiogenic inhibitors among them. We concluded that the bromoacetylcarbamoyl-2-nitroimidazole radiosensitizers, such as TX-1845 and TX-1846, are promising as anti-angiogenic hypoxic cell radiosensitizers.
    Bioorganic & Medicinal Chemistry 04/1997; 5(3):591-9. · 2.92 Impact Factor
  • Article: Angiotensin III is a new chemoattractant for polymorphonuclear leukocytes.
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    ABSTRACT: To clarify the role of angiotensin III (ANGIII) in inflammation, we examined the effect of ANGIII on the chemotaxis of human polymorphonuclear neutrophils (PMNs). The elicitation of PMN chemotaxis by ANGIII was dose dependent with an optimum dose of 10(-10) M. The time course for ANGIII-elicited chemotaxis showed a maximal level at 90 min, but N-formyl-Met-Leu-Phe (FMLP) elicited a maximal level of chemotaxis at 60 min. When ANGIII (10(-10) M) and FMLP (10(-7) M) were given in combination, the level of chemotaxis elicited was not significantly different from the levels attained with each peptide alone, suggesting that a similar pathway of signal transduction might be involved in the chemotaxis of PMNs elicited by ANGIII and FMLP. Thus, ANGIII is a new chemoattractant for PMNs that may use a signal transduction pathway similar to, but different from, that used by FMLP.
    Biochemical and Biophysical Research Communications 07/1993; 193(3):1038-43. · 2.48 Impact Factor
  • Article: Inhibition of angiogenesis by erbstatin, an inhibitor of tyrosine kinase.
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    ABSTRACT: Here we describe the inhibitory effect of erbstatin, a specific tyrosine kinase inhibitor, on in vivo angiogenesis. Inhibition of angiogenesis was determined in a bioassay system involving chorioallantoic membranes of growing chick embryos. Erbstatin produced a dose-dependent inhibitory action on embryonic angiogenesis. This inhibition occurred at as small a dose as 10 ng/egg and the ID50 value was 80 ng/egg. To analyze this inhibition, in vitro experiments involving vascular endothelial cells were also performed. Erbstatin affected the proliferation of vascular endothelial cells, one of angiogenic components. This inhibition was dose-dependent, the IC50 value being 3.6 microM. These data indicate that erbstatin-sensitive tyrosine kinase(s) is involved in angiogenic endothelial cell proliferation, and that experiments involving erbstatin will provide an important due to understand a mechanism of angiogenesis.
    The Journal of Antibiotics 06/1993; 46(5):785-90. · 1.65 Impact Factor
  • Article: Inhibition of angiogenesis by staurosporine, a potent protein kinase inhibitor.
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    ABSTRACT: The effect of staurosporine, a potent inhibitor of protein kinases, on embryonic angiogenesis was studied in an in vivo assay system involving chorioallantoic membranes of growing chick embryo. Staurosporine inhibited embryonic angiogenesis in a dose-related manner, the ID50 value being 71 pmol/egg. Staurosporine dose-dependently suppressed the proliferation of vascular endothelial cells, an important event involved in the angiogenesis process. The IC50 value was 0.88 nM. In contrast, staurosporine did not affect the migration of vascular endothelial cells. These results suggest that staurosporine affected embryonic angiogenesis probably by inhibiting endothelial cell proliferation. In addition, these results might support the notion that certain protein kinase(s) could be implicated in induction of angiogenesis and also that staurosporine would be a useful compound for studying a mode of action of angiogenesis occurring in various diseases, including tumor development.
    The Journal of Antibiotics 08/1992; 45(7):1155-60. · 1.65 Impact Factor
  • Article: Effect of 15-deoxyspergualin, a microbial angiogenesis inhibitor, on the biological activities of bovine vascular endothelial cells.
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    ABSTRACT: We found recently that 15-deoxyspergualin, an analog of spergualin, which is an antibiotic and includes a spermidine moiety in its structure, exhibits anti-angiogenic activity. We have now carried out in vitro experiments with bovine vascular endothelial cells to determine which events occurring during angiogenesis are affected by this microbial angiogenesis inhibitor. 15-Deoxyspergualin did not inhibit the production of urokinase-type plasminogen activator (u-PA) or type IV collagenase by vascular endothelial cells. The direct inhibition of u-PA activity by 15-deoxyspergualin was not observed either. The angiostatic antibiotic neither affected the migration of vascular endothelial cells nor inhibited the endothelial cell proliferation in a two-dimensional culture system. We also examined the effect of 15-deoxyspergualin on the proliferation of endothelial cells in a three-dimensional culture system involving collagen gel, in which cell growth resembles more closely the endothelial cell proliferation during in vivo angiogenesis than that in a two-dimensional culture system without collagen gel. The antibiotic inhibited cell proliferation in a dose-dependent manner, indicating that the three-dimensional culture system is useful for finding a new angiogenesis inhibitor with a different mode of action from those of angiogenesis inhibitors found by using a two-dimensional assay system; however, no cause-effect relationship has yet been established. Taken together, these results suggest the possible involvement of the inhibition of vascular endothelial cell growth by 15-deoxyspergualin in its angiogenesis-inhibitory effect. 15-Deoxyspergualin appears to be a promising candidate as an angiogenesis inhibitor for controlling aberrant angiogenic responses occurring in different states, including tumor development.(ABSTRACT TRUNCATED AT 250 WORDS)
    Anti-Cancer Drugs 07/1992; 3(3):293-9. · 2.41 Impact Factor
  • Article: Okadaic acid is a potent angiogenesis inducer.
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    ABSTRACT: Okadaic acid, which is a non-12-O-tetradecanoylphorbol-13-acetate (TPA)-type tumor promoter and an inhibitor of protein phosphatases 1 and 2A, induced angiogenesis in the chorioallantoic membrane of the chick embryo. Its potent angiogenic activity was dose-dependent. The minimum effective dose was 5 fmol/egg and the effective dose for 50% induction was 90 fmol/egg. These results indicated that okadaic acid exhibits angiogenic activity one order of magnitude stronger than that of TPA (reported previously). Moreover, the time-course of angiogenesis induction by okadaic acid was much slower than that by TPA. The difference is consistent with the time-courses of other biochemical and biological activities and also various gene expressions induced by okadaic acid and TPA, indicating that the difference in the time-course is associated with their mechanisms of action. We conclude that okadaic acid induces angiogenesis through a different pathway than does TPA, indicating the existence of a new mechanism of angiogenesis induction.
    Japanese journal of cancer research: Gann 02/1992; 83(1):6-9.
  • Article: Eponemycin, a novel antibiotic, is a highly powerful angiogenesis inhibitor.
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    ABSTRACT: Eponemycin, a novel antibiotic, was examined as to its anti-angiogenic activity in an in vivo assay system involving chorioallantoic membranes (CAMs) of growing chick embryos. Eponemycin powerfully inhibited angiogenesis in the CAMs. This powerful inhibition was dose-dependent, the inhibitory activity becoming detectable at a dose of 7.5 fmol/egg and the ID50 value being 250 fmol/egg, suggesting that eponemycin exhibits more potent anti-angiogenic activity than Ch 55, a synthetic retinoid, which had been the strongest angiogenesis inhibitor identified so far. To determine which event(s) in the angiogenesis process was affected by eponemycin, experiments were conducted using systems involving cultured vascular endothelial cells. Eponemycin effectively inhibited both the proliferation and migration of endothelial cells, indicating that the antibiotic affected these two important events during angiogenesis, resulting in effective inhibition of angiogenesis. These results strongly suggest that eponemycin could be a promising candidate as an angiogenesis inhibitor for the control of aberrant angiogenesis occurring in different diseases such as tumor development and diabetic retinopathy.
    Biochemical and Biophysical Research Communications 01/1992; 181(3):1070-6. · 2.48 Impact Factor
  • Article: Antitumor effect of 22-oxa-1 alpha,25-dihydroxyvitamin D3, a potent angiogenesis inhibitor, on rat mammary tumors induced by 7,12-dimethylbenz[a]anthracene.
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    ABSTRACT: The effect of 22-oxa-1 alpha,25-dihydroxyvitamin D3 (22-oxa-1,25(OH)2D3) on the growth of autochthonous rat mammary tumors induced by 7,12-dimethylbenz[a]anthracene (DMBA) was examined on the basis of our previous finding that this synthetic vitamin D3 analog has a potent angiogenesis inhibitory effect. Two doses of 22-oxa-1,25(OH)2D3, 0.1 and 1 microgram/kg of body weight, due to the limited amount of the compound available, were used. The daily administration of 22-oxa-1,25(OH)2D3 at the dose of 1 microgram/kg/day resulted in significant inhibition of the growth of these mammary tumors at 1, 2 and 3 weeks after the administration of this agent, although the agent caused little or no regression of the tumors. After daily administration for 3 weeks, a significant antitumor effect was also observed in the group treated with 0.1 microgram/kg/day. Treatment with 22-oxa-1,25(OH)2D3 did not affect the serum calcium levels in the treated rats. The lower dose of 22-oxa-1,25(OH)2D3 neither affected weight gain nor caused a decrease in body weight, while the higher dose, although having some effect on weight gain, did not induce a decrease in body weight. There were no significant differences in the weights of adrenals, uteri and ovaries between the treated groups and controls. These results suggest that 22-oxa-1,25(OH)2D3 has a significant growth inhibitory effect on DMBA-induced autochthonous mammary tumors in rats, without producing severe side effects, including hypercalcemic activity.(ABSTRACT TRUNCATED AT 250 WORDS)
    Anti-Cancer Drugs 11/1991; 2(5):475-80. · 2.41 Impact Factor
  • Article: Inhibition of angiogenesis by 15-deoxyspergualin.
    The Journal of Antibiotics 10/1991; 44(9):1033-5. · 1.65 Impact Factor
  • Article: Enkephalin-degrading aminopeptidase in the longitudinal muscle layer of guinea pig small intestine: its properties and action on neuropeptides.
    M Shimamura, T Hazato, T Iwaguchi
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    ABSTRACT: A membrane-bound enkephalin-degrading aminopeptidase was purified from the longitudinal muscle layer of the guinea pig small intestine by four steps of column chromatography using L-tyrosine beta-naphthylamide. The molecular weight of the enzyme was estimated to be 105,000 by gel filtration. The maximum activity was observed between pH 6.5 and 7.0. The Km value for leucine-enkephalin was 137 microM. The aminopeptidase activity toward aminoacyl beta-naphthylamide substrates was restricted to basic, neutral, and aromatic aminoacyl derivatives. No action was detected on acidic amino acid and proline derivatives. The enzyme was potently inhibited by the aminopeptidase inhibitors actinonin, amastatin, and bestatin, and bioactive peptides such as angiotensin III, substance P, and Met-Lys-bradykinin. The enzyme activity was also inhibited by the antibody against the purified serum enkephalin-degrading aminopeptidase of guinea pig at concentrations similar to those at which activity was observed toward serum enkephalin-degrading aminopeptidase and renal aminopeptidase M. The enzyme rapidly hydrolyzed Leu-enkephalin and Met-enkephalin with the sequential removal of the N-terminal amino acid residues. The enzyme also hydrolyzed two enkephalin derivatives, angiotensin III and neurokinin A. However, neurotensin, substance P, and bradykinin were not cleaved. These properties indicated that the membrane-bound enkephalin-degrading aminopeptidase in the longitudinal muscle layer of the small intestine is similar to the serum enkephalin-degrading aminopeptidase and resembles aminopeptidase M. It is therefore suggested to play an important role in the metabolism of some bioactive peptides including enkephalin in peripheral nervous systems in vivo.
    Journal of Biochemistry 04/1991; 109(3):492-7. · 2.37 Impact Factor
  • Article: Analysis of the forelimb crossed extension reflex in thalamic cats during stepping.
    T Fuwa, M Shimamura, I Tanaka
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    ABSTRACT: Forelimb crossed extension reflexes were examined in 22 thalamic cats. These reflexes were elicited either by backward passive movement or by repetitive electrical stimulation of cutaneous and joint afferent nerves in the contralateral forelimb. Single stimulation of the superficial radial nerve evoked two types of reflex responses--early (ER) and late (LR)--from the triceps brachii muscle on the contralateral side. The latencies were about 7 and 16-25 ms, corresponding to the propriospinal (PSR) and spino-bulbo-spinal (SBS) reflexes of the ipsilateral flexor, respectively. Repetitive stimulation of the superficial radial nerve evoked the LR but not the ER. The crossed extension reflex and LR were abolished by lesions of the dorsolateral funiculus of the cervical cord on the side opposite to the recording. The tonic EMG activity, crossed extension reflex and LR in the extensor on the side of lesions were abolished by lesions of the ventrolateral funiculus of the cervical cord. During forelimb stepping, the amplitudes of both ER and LR fluctuated depending on the phase of the step cycle. The ER appeared during a narrow period in the early phase of the stance, whereas the LR was observed during a wide period from the middle of the swing to the middle of the stance. Both responses were absent from the middle of the stance to the middle of the swing. These observations suggest that forelimb crossed extension reflexes involve both spinal and supraspinal (SBS) loop mechanisms, and that these are utilized during stepping, with the latter mechanism in particular playing an important part in the extension phase of the forelimb forward movement.
    Neuroscience Research 02/1991; 9(4):257-69. · 2.25 Impact Factor

Institutions

  • 1985–2003
    • Tokyo Metropolitan Institute of Medical Science
      Tokyo, Tokyo-to, Japan
  • 1979–1990
    • Tokyo Metropolitan Institute
      Tokyo, Tokyo-to, Japan
  • 1989
    • Juntendo University
      • Department of Anesthesiology
      Tokyo, Tokyo-to, Japan