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Iwamoto H, Miura T, Okamura T, Shirakawa K, Iwatate M, Kawamura S, Tatsuno H, Ikeda Y, Matsuzaki M. Calpain inhibitor-1 reduces infarct size and DNA fragmentation of myocardium in ischemic/reperfused rat heart. J Cardiovasc Pharmacol 1999; 33:580-6. [PMID: 10218728 DOI: 10.1097/00005344-199904000-00010] [Citation(s) in RCA: 66] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Myocardial ischemia/reperfusion activates a calcium-dependent protease, calpain, in the ischemic myocytes. It is not known whether calpain is involved in the mechanism of ischemia/reperfusion injury in hearts. Thus the purpose of this study was to clarify the effect of a selective calpain inhibitor (CAI) on infarct size and the extent of DNA damage in ischemic/reperfused rat hearts. Rats were divided in four groups (n = 7 each). In saline group, 0.3 ml of saline was administered (i.v.) 10 min before 30-min coronary occlusion followed by 6-h reperfusion. In vehicle group, 0.3 ml of 10% dimethyl sulfoxide (DMSO) was administered 10 min before the 30-min ischemia. CAI (0.5 mg/kg) was administered 10 min before the 30-min ischemia (CAI-A group) and 10 min before the 6-h reperfusion period (CAI-B group). Infarct size was detected with triphenyl tetrazolium chloride, and DNA fragmentation was detected by agarose gel electrophoresis and by in situ nick end labeling (ISEL). Infarct size was significantly smaller in the CAI-A group compared with the vehicle group (13+/-9% vs. 48+/-12%; p < 0.01), and the incidence of ISEL-positive myocyte nuclei in the subendocardial region was significantly reduced in the CAI-A group compared with the vehicle group (26+/-3% vs. 59+/-6%; p < 0.01). However, the effects of CAI in CAI-B group were not significant. Activation of calpain is involved in the mechanism of ischemia/reperfusion injury, and the preischemic administration of CAI was effective in reducing myocardial infarct size and the DNA damage of the myocytes in ischemic/reperfused rat heart.
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Czajkowsky DM, Iwamoto H, Cover TL, Shao Z. The vacuolating toxin from Helicobacter pylori forms hexameric pores in lipid bilayers at low pH. Proc Natl Acad Sci U S A 1999; 96:2001-6. [PMID: 10051584 PMCID: PMC26726 DOI: 10.1073/pnas.96.5.2001] [Citation(s) in RCA: 158] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/1998] [Accepted: 12/31/1998] [Indexed: 12/12/2022] Open
Abstract
Pathogenic strains of Helicobacter pylori secrete a cytotoxin, VacA, that in the presence of weak bases, causes osmotic swelling of acidic intracellular compartments enriched in markers for late endosomes and lysosomes. The molecular mechanisms by which VacA causes this vacuolation remain largely unknown. At neutral pH, VacA is predominantly a water-soluble dodecamer formed by two apposing hexamers. In this report, we show by using atomic force microscopy that below pH approximately 5, VacA associates with anionic lipid bilayers to form hexameric membrane-associated complexes. We propose that water-soluble dodecameric VacA proteins disassemble at low pH and reassemble into membrane-spanning hexamers. The surface contour of the membrane-bound hexamer is strikingly similar to the outer surface of the soluble dodecamer, suggesting that the VacA surface in contact with the membrane is buried within the dodecamer before protonation. In addition, electrophysiological measurements indicate that, under the conditions determined by atomic force microscopy for membrane association, VacA forms pores across planar lipid bilayers. This low pH-triggered pore formation is likely a critical step in VacA activity.
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178
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Yoshida O, Yoshida H, Iwamoto H, Nishino K, Fukushima A, Ueno H. Genetic background determines the nature of immune responses and experimental immune-mediated blepharoconjunctivitis (EC). Curr Eye Res 1999; 18:117-24. [PMID: 10223655 DOI: 10.1076/ceyr.18.2.117.5383] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
Abstract
PURPOSE Experimental immune-mediated blepharoconjunctivitis (EC) was induced in Lewis rats by immunization with ovalbumin (OVA) in complete Freund's adjuvant (CFA) or aluminum hydroxide [Al(OH)3]. To investigate the affect of genetic factors on the susceptibility of EC, we tested different strains of rats for the development of EC. METHODS Lewis and Brown Norway (BN) rats were immunized once with 100 microg of OVA in CFA or Al(OH)3. Three weeks later they were challenged with OVA in eye drops; 24 hours after the challenge they were sacrificed and their eyes, blood, and lymph nodes were harvested for histological studies, measurement of OVA-specific antibodies (IgG, IgG1, IgG2a, IgE), and proliferation or cytokine assay, respectively. ELISA was used to detect OVA-specific IgG; passive cutaneous anaphylaxis was used for detecting IgE. RESULTS EC, OVA-specific IgG, and cellular immunity were induced in Lewis rats by using either adjuvant, whereas IgE was not produced by either adjuvant. In contrast, IgE was produced in BN rats using either adjuvant, whereas cellular immunity was evoked only when CFA was used. Less cellular infiltration as well as cellular proliferation was detected in BN rats immunized with Al(OH)3. In both strains, Al(OH)3 induced a higher IgG1/IgG2a ratio than did CFA. More interferon-gamma by stimulation with OVA was noted in Lewis rats compared to BN rats, whereas interleukin-4 was detected only in BN rats. CONCLUSIONS The severity of EC evaluated by cellular infiltration was dependent on OVA-specific cellular immunity. Genetic background is more important than adjuvants in determining the nature of EC and immunity.
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Tanaka Y, Masuno M, Iwamoto H, Aida N, Ijiri R, Yamanaka S, Imaizumi K, Kuroki Y. Noonan syndrome and cavernous hemangioma of the brain. AMERICAN JOURNAL OF MEDICAL GENETICS 1999; 82:212-4. [PMID: 10215542 DOI: 10.1002/(sici)1096-8628(19990129)82:3<212::aid-ajmg3>3.0.co;2-4] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
We present two patients with multiple characteristics that occur in Noonan phenotype and cavernous hemangioma of the brain. The first patient, who had been diagnosed radiographically as having a cavernous hemangioma in the left basal ganglia at age 15 years, developed massive intracerebral hemorrhage, resulting in sudden death at home at 19 years. The second patient, who was diagnosed radiographically as having a cavernous hemangioma in the left parietal lobe at age 17 years, is being followed carefully (the patient is currently 18 years old). A review disclosed four cases of structural cerebrovascular abnormalities with or without subsequent hemorrhage. Neither these four patients nor our two patients had any severe anomalies in the heart or large vessels, which are frequently seen in patients with Noonan syndrome. Cerebrovascular abnormalities might have a significant influence on the prognosis of patients with Noonan syndrome, especially those having no severe abnormalities in the heart or large vessels.
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Sugi H, Iwamoto H, Akimoto T, Ushitani H. Load-dependent mechanical efficiency of individual myosin heads in skeletal muscle fibers activated by laser flash photolysis of caged calcium in the presence of a limited amount of ATP. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 1999; 453:557-66; discussion 567. [PMID: 9889868 DOI: 10.1007/978-1-4684-6039-1_61] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
Although a contracting muscle regulates its energy output depending on the load imposed on it ("Fenn effect"), the mechanism underlying the load-dependent energy output remains obscure. To explore the possibility that the mechanical efficiency, with which chemical energy derived from ATP hydrolysis is converted into mechanical work, of individual myosin heads changes in a load-dependent manner, we examined the auxotonic shortening of glycerinated rabbit psoas muscle fibers, containing ATP molecules almost equal in number to the myosin heads, following laser flash photolysis of caged calcium. Immediately before laser flash activation, almost all of the myosin heads in the fiber are in the state, M.ADP.Pi, and can undergo only one ATP hydrolysis cycle after activation. When the fibers were activated to shorten under various auxotonic loads, the length, force and power output changes were found to be scaled according to the auxotonic load. Both the power and energy outputs were maximal under a moderate auxotonic load. The amount of M.ADP.Pi utilized at a time after activation was estimated from the amount of isometric force developed after interruption of fiber shortening. This amount was minimal in the isometric condition, and increased nearly in proportion to the distance of fiber shortening. These results are taken as evidence that the efficiency of chemo-mechanical energy conversion in individual myosin heads changes in a load-dependent manner.
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Seki S, Iwamoto H. Disruptive forces for swine heart, liver, and spleen: their breaking stresses. THE JOURNAL OF TRAUMA 1998; 45:1079-83. [PMID: 9867052 DOI: 10.1097/00005373-199812000-00019] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
Abstract
OBJECTIVES The mechanical strengths of the swine heart, liver, and spleen were determined by measuring the force that initiated the rupture of the organs. METHODS The force was loaded by the compression of a detection bar onto the organ, and the breaking stress was calculated by dividing the force by the bar's contact area. The forces were measured with five measurements in five of each type of organ with and without the serous membrane (SM). RESULTS The breaking stresses of the heart were 14.1+/-0.7 kg/cm2 (mean+/-SEM) with intact epicardium and 8.1+/-0.6 without it; those of the spleen were 9.0+/-0.9 with its capsule and 1.8+/-0.1 without the capsule, and those of the liver were 4.6+/-0.3 with and 3.6+/-0.3 without the SM. A three-way layout analysis of variance showed that the organs, their SM and individual swine were independent determinants of the breaking stresses. CONCLUSION With the intact SM, the heart was strongest and the liver was weakest. When the SM was not present, the spleen lost 80% of its strength, the liver 22% of its strength, and the heart lost 43% of its strength.
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Iwamoto H, Katoh F, Gotoh T, Nishimura S, Ono Y, Nishio Y, Fukuhara E, Murakami T. Effects of parent Shamo cocks on the histochemical properties of M. iliotibialis lateralis and M. supracoracoideus on their crossbred broilers. Br Poult Sci 1998; 39:589-95. [PMID: 9925310 DOI: 10.1080/00071669888449] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/16/2022]
Abstract
1. Four Shamo (a Japanese game bird) cocks showing different characteristics in the histochemical properties of M. iliotibialis lateralis (ITL) were crossed with White Rock hens to produce male and female crossbred broilers of the 4 lines (90 d of age). Normal broilers (56 d) were used, for comparison. 2. Histochemical properties of ITL and M. supracoracoideus (SC) were compared among the crossbred lines and normal broilers. Myofibres were divided into Types II R, II I and II W showing high, moderate and low reduced nicotinamide adenine dinucleotide dehydrogenase (NADH-DH) activities, respectively. 3. In the ITL of the crossbred cockerels, the percentage of Type II R and II I fibres decreased and conversely Type II W increased in comparison to those in the Shamo. 4. Sex differences of the histochemical properties were recognised only in the ITL of the crossbred, in which the percentage of Type II R fibres was greater in the male. 5. The different characteristics of the parent Shamo cocks were reproduced only in the different fibre type composition of the ITL muscle in the crossbred cockerels. 6. The histochemical features of fibre type seemed to develop with bird age, particularly subsarcolemmal accumulation of formazan granules (indicating high NADH-DH activity) in Type IIR fibres. 7. Breed, line, sex and age differences in the histochemical properties were demonstrated clearly in ITL but not in SC.
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Abstract
BACKGROUND/AIMS Activation of hepatic stellate cells plays a key role in liver fibrogenesis. Disruption of normal hepatic stellate cell-matrix interactions may contribute to this process. However, little is known about the molecular events leading from integrin-extracellular matrix interaction to hepatic stellate cell function. Therefore, we investigated the role of integrin signaling in tyrosine phosphorylation of focal adhesion kinase and cytoskeletal assembly in rat hepatic stellate cells using soluble Arg-Gly-Asp containing peptides. METHODS Hepatic stellate cells were isolated from normal rat livers. Integrin alpha5beta1 expression in hepatic stellate cells was analyzed by immunoprecipitation and immunocytochemistry. The cytoskeletal assembly and tyrosine phosphorylation of focal adhesion kinase were determined by immunocytochemistry and immunoblotting. We also analyzed the effect of Arg-Gly-Asp containing peptides on the expression of smooth muscle alpha actin by immunocytochemistry and immunoblotting. RESULTS We identified integrin alpha5beta1 in rat hepatic stellate cells. Stress fiber formation and cell shape were different when hepatic stellate cells were plated on various extracellular matrix components. Treatment of hepatic stellate cells with soluble Arg-Gly-Asp peptides diminished the adhesion-induced tyrosine phosphorylation of focal adhesion kinase and inhibited the formation of stress fibers. The peptides also reduced the expression of smooth muscle alpha actin. CONCLUSIONS Our results demonstrate that adhesion to extracellular matrix induces tyrosine phosphorylation of focal adhesion kinase and promotes actin stress fiber formation and focal adhesion assembly in rat hepatic stellate cells, and that these events are disturbed by soluble Arg-Gly-Asp peptides.
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Yoshida O, Yoshida H, Iwamoto H, Nishino K, Fukushima A, Ueno H. Comparison of genetic susceptibility to experimental allergic/immune-mediated blepharoconjunctivitis between Lewis and Fischer rats. Graefes Arch Clin Exp Ophthalmol 1998; 236:859-64. [PMID: 9825262 DOI: 10.1007/s004170050171] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/28/2022] Open
Abstract
BACKGROUND Fischer rats were less susceptible to experimental autoimmune uveoretinitis (EAU) than Lewis rats, although both strains have the same MHC molecules. The purpose of this study was to compare the susceptibility of experimental allergic/immune-mediated blepharoconjunctivitis (EAC) between these two strains. METHODS Male Lewis and Fischer rats were immunized with either ovalbumin (OVA) or OVA peptide (OVA323-339) in complete Freund's adjuvant (CFA). Three weeks later, they were challenged with OVA by eye drops. Twenty-four hours later, after clinical evaluation, they were killed and eyes, blood and lymph nodes were harvested for histology, antibody titer and proliferation assay, cytokine production or flow cytometric analysis, respectively. RESULTS Fischer rats developed mild EAC compared with Lewis rats. Cellular proliferative responses, IFN-gamma production of culture supernatant and serum IgG specific for OVA were basically the same between the two strains. The same OVA peptides were selected as immunodominant. Flow cytometric analysis demonstrated the same cellular profile of lymph node cells in the two strains. CONCLUSION EAC in Fischer rats was milder than that in Lewis rats, although no apparent differences in immunological parameters between these two strains were detected. These data suggest that factors unrelated to immunological parameters may depend on the susceptibility of EAC.
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185
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Motomiya Y, Oyama N, Iwamoto H, Uchimura T, Maruyama I. N epsilon-(carboxymethyl)lysine in blood from maintenance hemodialysis patients may contribute to dialysis-related amyloidosis. Kidney Int 1998; 54:1357-66. [PMID: 9767556 DOI: 10.1046/j.1523-1755.1998.00091.x] [Citation(s) in RCA: 21] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Abstract
BACKGROUND Recent studies demonstrated not only that advanced glycation end product could be found in amyloid tissue from patient with dialysis related amyloidosis, but also that amyloid beta2-microglobulin was modified with N(epsilon)-(carboxymethyl)lysine (CML). We wanted to determine if CML could be a biomarker in these patients. METHODS To raise polyclonal anti-carboxymethyllysine antibody, human serum albumin was carboxymethylated by glyoxylic acid and was immunized to rabbits as antigen. Carboxymethyllysine-hemoglobin (CML-Hb) levels were measured by the dot blotting method using this antibody. RESULTS The levels of CML-Hb were 6.68 +/- 3.10 nmol CML/mg Hb in nondiabetic hemodialysis patients (N = 70), 6.39 +/- 3.43 nmol CML/mg Hb in diabetic hemodialysis patient (N = 21), and 3.13 +/- 0.88 nmol CML/mg Hb in 47 healthy volunteers. For clinical signs of dialysis-related amyloidosis, 70 nondiabetic hemodialysis patients were scored according Gejyo's criteria. The CML-Hb levels in patients with a high amyloid score as well as a low amyloid score were significantly higher than in patients with negative amyloid score (8.89 +/- 3.53 nmol CMLmg Hb, 7.28 +/- 2.32 nmol CML/mg Hb vs. 5.11 +/- 2.09 nmol CML/mg Hb, P < 0.001, P < 0.05). Furthermore, the CML-Hb levels correlated significantly with serum values of the methylguanidine over creatinine ratio and hyaluronate. CONCLUSIONS We suggest that CML-Hb is increased in blood from patients on maintenance hemodialysis and is thus a potential biomarker of oxidative damage in these patients. Moreover, CML-modification of protein may play a pathogenic role in the development of dialysis related amyloidosis.
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Yoshida H, Yoshida O, Iwamoto H, Nishino K, Hashida M, Fukushima A, Ueno H. Analysis of effects of stimulation in vitro of ovalbumin primed lymph node cells on adoptive transfer of experimental immune mediated blepharoconjunctivitis in Lewis rats. Br J Ophthalmol 1998; 82:1189-94. [PMID: 9924309 PMCID: PMC1722375 DOI: 10.1136/bjo.82.10.1189] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
AIM To analyse the role of stimulation in vitro of lymphocytes on the augmentation of experimental immune mediated blepharoconjunctivitis (EC, formerly EAC) in Lewis rats induced by adoptive transfer. METHODS Two weeks after immunisation with ovalbumin (OVA), rat draining lymph nodes were collected and 50 x 10(6) cells were injected into naive syngeneic recipients either directly or after culture in vitro with OVA, concanavalin A (Con A), or purified protein derivative (PPD) for 3 days. Four days after injection the rats were topically challenged with OVA. 24 hours later, they were sacrificed and eyes and spleens were harvested for histology and proliferation assay. In some experiments, naive recipient rats were irradiated with 7 Gy gamma ray before transfer. The expression of adhesion molecules and cytokine profile of OVA primed lymph node cells were also investigated. RESULTS Both infiltrated cell number and splenocyte proliferation in the recipients of stimulated cells were higher than those of unstimulated cells. In vitro stimulation with OVA or Con A induced a severe cellular infiltration, while stimulation with PPD did not. Irradiation markedly diminished cellular infiltration. Stimulation in vitro upregulated the CD4/CD8 ratio by four times and augmented expression of CD25, I-A, ICAM-1 molecules on OVA primed lymph node cells by about five times. IFN-gamma was detected in OVA primed cells by stimulation in vitro, while IL-4 mRNA was extinguished by stimulation in vitro. CONCLUSIONS Augmentation of EC by stimulation in vitro of transferred lymphocytes might depend on the upregulation of expression of cell surface molecules and cytokine shift as well as augmented antigen specificity.
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Onishi Y, Hotta S, Iwamoto H, Kamoshida T, Takahashi A, Imai Y. [An autopsy case of intravascular malignant lymphomatosis with hemophagocytic syndrome, mental confusion and liver dysfunction]. [RINSHO KETSUEKI] THE JAPANESE JOURNAL OF CLINICAL HEMATOLOGY 1998; 39:586-92. [PMID: 9785977] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
A 66-year-old Japanese man was admitted to Hitachi General Hospital because of fatigue, fever, edema, and icterus. A blood examination showed anemia, leukocytosis, and hyperbilirubinemia. Antibiotics did not alleviate the inflammatory symptoms. On the 13th hospital day, the patient demonstrated mental confusion, with progressive anemia and thrombocytopenia. Bone marrow aspiration revealed an increase of macrophages showing erythrophagocytosis. A diagnosis of hemophagocytic syndrome was made, but no viral infection or hematological malignancy could be detected. The patient was treated with gamma-globulin and methylprednisolone for hemophagocytic syndrome, but died of respiratory insufficiency with progressive hyperbilirubinemia and trombocytopenia on the 29th hospital day, A postmortem examination showed proliferation of lymphoma cells within the small blood vessels of the brain, lungs, liver, and many other organs, but the bone marrow was not involved. An immunohistochemical examination resulted in a diagnosis of intravascular malignant lymphomatosis (IML) of B cell origin. No viral infection was detected with in situ hybridization methods. Although IML occasionally accompanies thrombocytopenia, infiltration of lymphoma cells in the bone marrow is rare. Lymphoma associated hemophagocytic syndrome may cause cytopenia in some patients with IML, as indicated in this case.
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Iwami T, Fujii T, Miura T, Otani N, Iida H, Kawamura A, Yoshitake S, Kohno M, Hisamatsu Y, Iwamoto H, Matsuzaki M. Importance of left anterior descending coronary artery curvature in determining cross-sectional plaque distribution assessed by intravascular ultrasound. Am J Cardiol 1998; 82:381-4. [PMID: 9708671 DOI: 10.1016/s0002-9149(98)00340-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
We assessed the relation between the circumferential distribution of coronary atherosclerotic plaques and the structure of the epicardial coronary arteries in patients with coronary artery disease using intravascular ultrasound in vivo. Coronary atherosclerosis preferentially formed at the inner arc of the curved coronary vessels, and greater vessel curvatures were associated with greater distributions of atherosclerotic lesions along the inner coronary artery wall.
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Wada T, Nakamura M, Matsushita Y, Yamada M, Yamashita S, Iwamoto H, Masuno M, Imaizumi K, Kuroki Y. [Three Japanese children with X-linked alpha-thalassemia/mental retardation syndrome (ATR-X)]. NO TO HATTATSU = BRAIN AND DEVELOPMENT 1998; 30:283-9. [PMID: 9695621] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
X-linked alpha-thalassemia/mental retardation syndrome (ATR-X), which was first reported by Wilkie, et al. in 1991, is a disorder with severe mental retardation, characteristic facial appearance, genital abnormalities, and mild form of alpha-thalassemia. At present, about 50 cases have been reported in the world, but few in Japan. We report 3 cases of this disorder in 2 families. All cases prefer a peculiar posture and show unique movements, such as self-induced vomiting or self-hanging, which can be diagnostic. ATR-X should be considered as a differential diagnosis in all male patients with severe mental retardation.
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Tabata S, Ozaki HS, Nakashima M, Uemura M, Iwamoto H. Innervation of blood vessels in the rat incisor pulp: a scanning electron microscopic and immunoelectron microscopic study. Anat Rec (Hoboken) 1998; 251:384-91. [PMID: 9669766 DOI: 10.1002/(sici)1097-0185(199807)251:3<384::aid-ar14>3.0.co;2-k] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Although two types of nerve endings have been proposed to innervate blood vessels in the dental pulp, the precise innervation pattern is not well understood. This is mainly due to the lack of information regarding the positional relationships of nerve fibers with blood vessels at the electron microscopic level. The rat incisor pulp was investigated by scanning electron microscopy (SEM) after connective tissue digestion and by transmission electron microscopy after immunohistochemical localization with polyclonal anti-PGP 9.5 antibody. SEM specimens revealed that unmyelinated nerve fibers passed through the tunica adventitia of the blood vessel in the center of the pulp and that these fibers then entered the tunica media of the smaller arterioles. The nerve fibers divided into many collaterals, and these terminated on the surface of smooth muscle cells and endothelial cells. The fibers extended toward smaller vessels. The terminal fibers then reached the subodontoblastic capillary plexus and terminated on pericytes, while the odontoblastic capillary plexus had no direct innervation. In the pulpal venules, nerve fibers were located adjacent to the pericytes and endothelial cells, and they extended toward postcapillary venules. The same results were confirmed by immunoelectron microscopy. The present study demonstrated that in the rat incisor pulp the microvasculature as well as larger vessels were directly innervated by free nerve endings, suggesting that the local regulation of blood flow could take place not only at larger vessels but also at the level of the microvasculature in this tissue.
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Wakabayashi K, Sugiyama H, Yagi N, Irving TC, Iwamoto H, Horiuti K, Takezawa Y, Sugimoto Y, Ogino M, Iino S, Kim DS, Majima T, Amemiya Y, Yamamoto S, Ando M. High-Resolution X-ray Diffraction of Muscle Using Undulator Radiation from the Tristan Main Ring at KEK. JOURNAL OF SYNCHROTRON RADIATION 1998; 5:280-285. [PMID: 15263492 DOI: 10.1107/s0909049597013861] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/04/1997] [Accepted: 10/16/1997] [Indexed: 05/24/2023]
Abstract
High Energy Accelerator Research Organization (KEK), Tsukuba, Japan.High-resolution X-ray diffraction studies on striated muscle fibres were performed using a hard X-ray undulator installed in the Tristan main ring at KEK, Tsukuba, Japan. The performance of the undulator, along with an example experiment which exploited the unique characteristics of undulator radiation, are reported. The vertical divergence angle of the first harmonic of the undulator was approximately 10 micro rad under 8 GeV multi-bunch operating conditions and the peak photon flux density was estimated to be approximately 3 x 10(16) photons s(-1) mrad(-2) (0.1% bandwidth)(-1) (10 mA)(-1). The well collimated X-ray beam from the undulator made it possible to resolve clearly, with high angular resolution ( approximately 700 nm), the closely spaced diffraction peaks on the meridional axis in the X-ray patterns arising from the thick filaments of a striated muscle under static conditions. By fitting the meridional intensity pattern, a model for the molecular arrangement of the constituent proteins in the thick filaments is proposed. These studies of muscle demonstrate the promise of undulator radiation from third-generation sources for high-resolution diffraction studies.
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Takegawa K, Fujita K, Fan JQ, Tabuchi M, Tanaka N, Kondo A, Iwamoto H, Kato I, Lee YC, Iwahara S. Enzymatic synthesis of a neoglycoconjugate by transglycosylation with Arthrobacter endo-beta-N-acetylglucosaminidase: a substrate for colorimetric detection of endo-beta-N-acetylglucosaminidase activity. Anal Biochem 1998; 257:218-23. [PMID: 9514782 DOI: 10.1006/abio.1997.2543] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The transglycosylation activity of endo-beta-N-acetylglucosaminidase from Arthrobacter protophormiae was used for the enzymatic synthesis of a novel oligosaccharide, Man6GlcNAc-p-nitrophenyl-alpha-D-glucose (Man6GlcNAc-Glc-pNP). The reaction was efficiently induced in aqueous solution containing dimethyl sulfoxide. In the medium containing 20% (v/v) dimethyl sulfoxide with 0.1 M Glc-pNP as an acceptor, the transglycosylation attained yields of 75% by high-performance anion-exchange chromatography. The structure of Man6GlcNAc-Glc-pNP was confirmed by ion mass spectrometry and 400 MHz 1H NMR spectrometry. Various endo-beta-N-acetylglucosaminidases hydrolyzed this oligosaccharide and Man6GlcNAc and Glc-pNP were released from the oligosaccharide by endo-beta-N-acetylglucosaminidase digestion. We have established a new procedure for the colorimetric detection of endo-beta-N-acetylglucosaminidase activity using Man6Glc-NAc-Glc-pNP, which is simple as that for other exoglycosidase assays with pNP-glycosides as substrates.
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Sugi H, Iwamoto H, Akimoto T, Ushitani H. Evidence for the load-dependent mechanical efficiency of individual myosin heads in skeletal muscle fibers activated by laser flash photolysis of caged calcium in the presence of a limited amount of ATP. Proc Natl Acad Sci U S A 1998; 95:2273-8. [PMID: 9482875 PMCID: PMC19317 DOI: 10.1073/pnas.95.5.2273] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
Although a contracting muscle regulates its energy output depending on the load imposed on it ("Fenn effect"), the mechanism underlying the load-dependent energy output remains obscure. To explore the possibility that the mechanical efficiency, with which chemical energy derived from ATP hydrolysis is converted into mechanical work, of individual myosin heads changes in a load-dependent manner, we examined the auxotonic shortening of glycerinated rabbit psoas muscle fibers, containing ATP molecules almost equal in number to the myosin heads, after laser-flash photolysis of caged calcium. Immediately before laser-flash activation, almost all of the myosin heads in the fiber are in the state M.ADP.Pi, and can undergo only one ATP hydrolysis cycle after activation. When the fibers were activated to shorten under various auxotonic loads, the length, force, and power output changes were found to be scaled according to the auxotonic load. Both the power and energy outputs were maximal under a moderate auxotonic load. The amount of M.ADP.Pi utilized at a time after activation was estimated from the amount of isometric force developed after interruption of fiber shortening. This amount was minimal in the isometric condition and increased nearly in proportion to the distance of fiber shortening. These results are taken as evidence that the efficiency of chemomechanical energy conversion in individual myosin heads changes in a load-dependent manner.
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Iwamoto H. Thin filament cooperativity as a major determinant of shortening velocity in skeletal muscle fibers. Biophys J 1998; 74:1452-64. [PMID: 9512041 PMCID: PMC1299491 DOI: 10.1016/s0006-3495(98)77857-9] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
The mechanism underlying the calcium sensitivity of the velocity of shortening of skeletal muscle fibers was investigated using a multiple shortening protocol: within a single contraction, skinned rabbit psoas fibers were made to shorten repetitively under a light load by briefly stretching back to their initial length at regular intervals. At saturating [Ca2+], the initial fast shortening pattern was repeated reproducibly. At submaximal [Ca2+], the first shortening consisted of fast and slow phases, but only the slow phase was observed in later shortenings. When the fibers were held isometric after the first shortening, the velocity of the second shortening recovered with time. The recovery paralleled tension redevelopment, implying a close relationship between the velocity and the number of the preexisting force-producing cross-bridges. However, this parallelism was lost as [Ca2+] was increased. Thus, the velocity was modified in a manner consistent with the cooperative thin filament activation by strong binding cross-bridges and its modulation by calcium. The present results therefore provide evidence that the thin filament cooperativity is primarily responsible for the calcium sensitivity of velocity. The effect of inorganic phosphate to accelerate the slow phase of shortening is also explained in terms of the cooperative activation.
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Sano K, Yoshida S, Ninomiya H, Ikeda H, Ueno K, Sekine J, Iwamoto H, Uehara M, Inokuchi T. Assessment of growth potential by MIB-1 immunohistochemistry in ameloblastic fibroma and related lesions of the jaws compared with ameloblastic fibrosarcoma. J Oral Pathol Med 1998; 27:59-63. [PMID: 9526730 DOI: 10.1111/j.1600-0714.1998.tb02094.x] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Specimens from two ameloblastic fibromas (including one recurrent case), two ameloblastic fibro-odontomas, and one ameloblastic fibrosarcoma were subjected to investigation by MIB-1 immunohistochemistry in order to elucidate the growth potential of these tumors. MIB-1 labeling indices in the epithelial component of these tumors ranged from 2.9 to 7.5%, whereas those in the mesenchymal component ranged from 1.5 to 13.5%. Of these, labeling indices in the mesenchymal component of the recurrent ameloblastic fibroma and ameloblastic fibrosarcoma were quite high. These findings suggest that evaluation of growth potential in ameloblastic fibroma and related lesions could be of help in understanding tumor aggressiveness and in selecting appropriate surgical procedures.
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Iwamoto H. Effect of a cardiotonic agent, MCI-154, on the contractile properties of skinned skeletal muscle fibers. Eur J Pharmacol 1998; 341:243-52. [PMID: 9543245 DOI: 10.1016/s0014-2999(97)01469-6] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
We have studied the effect of a cardiotonic agent, MCI-154 (6-[4-(4-pyridylamino)phenyl]-4,5-dihydro-3(2H)-pyridazinone hydrochloride trihydrate), on the contractile properties and adenosine triphosphatase (ATPase) activity of chemically skinned rabbit skeletal muscle fibers. As in cardiac muscle, MCI-154 potentiated isometric tension and improved isometric tension cost at full Ca2+ activation. It showed little Ca2+-sensitizing effect. In contrast to its effect on cardiac muscle, however, MCI-154 decreased all the kinetic parameters tested (shortening velocity, the rate of rise of tension, and actomyosin ATPase activity). All the results are explainable if MCI-154 acts directly on skeletal actomyosin and inhibits a reaction step(s) of the ATPase cycle later than the force-generating event. The qualitative difference between cardiac and skeletal muscles in the responsiveness to this class of cardiotonic agents (MCI-154 and EMD 53998, a thiadiazinone derivative) is most readily understood if the agents have two independent actions, one on troponin and the other on actomyosin itself, the latter being dominant in skeletal muscle.
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Iwamoto H, Kiyohara Y, Fujishima M. [Physiopathology of sudden death--cerebrovascular disorders]. NIHON NAIKA GAKKAI ZASSHI. THE JOURNAL OF THE JAPANESE SOCIETY OF INTERNAL MEDICINE 1998; 87:58-62. [PMID: 9513548] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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198
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Nakajima M, Shinoda I, Mikogami T, Iwamoto H, Hashimoto S, Miyauchi H, Fukuwatari Y, Hayasawa H. Beta-lactoglobulin suppresses melanogenesis in cultured human melanocytes. PIGMENT CELL RESEARCH 1997; 10:410-3. [PMID: 9428009 DOI: 10.1111/j.1600-0749.1997.tb00700.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The effects of whey proteins from bovine milk on melanogenesis in cultured human melanocytes were examined. Among the major protein components of milk whey including beta-lactoglobulin (BLG), alpha-lactalbumin, serum albumin, and IgG, only BLG exhibited the depigmenting effect at a concentration of 1 mg/ml. Also, BLG suppressed the activity of tyrosinase in these cells. Retinol, to which BLG is known to bind, slightly increased the pigmentation of the cells at concentrations in the range of 1-100 nM, and retinoic acid, a metabolite of retinol, exhibited a strong pigmentation-promoting effect within the same concentration range. Treatment of the cells with 1 mg/ml BLG completely abrogated the pigmentation induced by these A vitamins. These results demonstrate a novel biological activity of BLG and suggest that this activity is dependent on its ability to bind retinol.
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Iwamoto H, Matsuda H, Noriage A, Yamano Y. Lumbar spinal canal stenosis examined electrophysiologically in a rat model of chronic cauda equina compression. Spine (Phila Pa 1976) 1997; 22:2636-40. [PMID: 9399449 DOI: 10.1097/00007632-199711150-00011] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
STUDY DESIGN A model of chronic cauda equina compression with conductive stress was studied electrophysiologically. OBJECTIVE To analyze the pathophysiology arising from chronic compression electrophysiologically. SUMMARY OF BACKGROUND DATA This rat model of cauda equina compression that is chronic, not acute, has been reported elsewhere. METHODS A stainless steel wire and plate were fastened to the spine at L5 of 8 rats 3 weeks old. One year later, the ascending and descending nerve action potentials were recorded and the conduction velocities (CVs) were measured. Electrophysiologic changes after high-frequency stimulation (HFS) were observed. RESULTS The waveform of the ascending cauda equina action potential at the cauda equina had three peaks, and that at the conus medullaris had a peak followed by a broad wave. The waveform of the descending nerve action potential had two peaks. The mean ascending and descending CVs of the treated rats were slower (P < 0.001) than those of the control rats. In the control rats, the mean CV and mean amplitude after HFS decreased slightly and returned to normal within 30 seconds, and the waveform was unchanged. In treated rats, the mean CV decreased after HFS but returned to normal within 10 minutes. The mean amplitude decreased after HFS and did not return to normal within 10 minutes. The waveform was unchanged. CONCLUSIONS Because the differences between treated and control rats in amplitude (and CVs) were greater before HFS than after HFS, we concluded that treated rats had disturbance of the blood flow in vessels around the nerves of the cauda equina with histologic damage. In human patients, such disturbance may be one cause of intermittent claudication.
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Nakayama K, Koyohara Y, Kato I, Iwamoto H, Ueda K, Fujishima M. [Effect of body mass index on morbidity and mortality in a general Japanese population--the Hisayama study]. Nihon Ronen Igakkai Zasshi 1997; 34:935-41. [PMID: 9483954 DOI: 10.3143/geriatrics.34.935] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
In order to investigate the effect of body mass index (BMI, kg/m2) on life expectancy, 2053 Hisayama residents, aged 40 years or older were studied for 13 years from 1974. During the follow-up period, 419 subjects died; of these, 39 deaths due to accident or suicide were excluded from further analysis. On initial examination, male subjects with BMI > or = 27 had significantly higher age-adjusted prevalence rates of hypertension, glucose intolerance, hypercholesterolemia, electrocardiogram abnormalities and proteinuria, as compared with those with 23-25 BMI. In contrast, the frequency of male smokers was inversely associated with BMI levels. Female prevalence rates of glucose intolerance, hypercholesterolemia and proteinuria were significantly higher in 25-27 BMI than in 23-25. Body Mass Index showed a U-shaped relationship with all cause mortality rates with the lowest rate in 23-27 BMI for men and in 23-25 BMI for women. These associations remained substantially unchanged, even after controlling for age, systolic blood pressure, glucose intolerance, serum cholesterol, proteinuria, electrocardiogram abnormalities, alcohol consumption, and smoking habits. When analyzing the BMI mortality relationship by cause of death, age- and sex-adjusted mortality rates from myocardial infarction and stroke significantly increased in subjects with BMI > or = 27 compared with those with 23-25 BMI. In contrast, there was a decreasing risk of death from malignant neoplasms with rising BMI levels, but the relationship was not significant. Mortality from pneumonia and other causes showed a U-shaped relationship with significantly higher rates seen in BMI < 19 than in 23-25 BMI. These data indicate that BMI has a U-shaped relationship with total mortality in the general Japanese population, which results from various associations between BMI and cause-specific mortality rates.
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