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Biomedical subjects

H Horie

Publications and source records attributed to H Horie.

At least 91 records · Page 5Linked to original sources
PubMed1997

Active sites of salivary proline-rich protein for binding to Porphyromonas gingivalis fimbriae.

Porphyromonas gingivalis fimbriae specifically bind salivary acidic proline-rich protein 1 (PRP1) through protein-protein interactions. The binding domains of fimbrillin (a subunit of fimbriae) for PRP1 were analyzed previously (A. Amano, A. Sharma, J.-Y. Lee, H. T. Sojar, P. A. Raj, and R. J. Genco, Infect. Immun. 64:1631-1637, 1996). In this study, we investigated the sites of binding of the PRP1 molecules to the fimbriae. PRP1 (amino acid residues 1 to 150) was proteolysed to three fragments (residues 1 to 74 [fragment 1-74], 75 to 129, and 130 to 150). 125I-labeled fimbriae clearly bound fragments 75-129 and 130-150, immobilized on a polyvinylidene difluoride membrane; both fragments also inhibited whole-cell binding to PRP1-coated hydroxyapatite (HAP) beads by 50 and 83%, respectively. However, the N-terminal fragment failed to show any effect. Analogous peptides corresponding to residues 75 to 89, 90 to 106, 107 to 120, 121 to 129, and 130 to 150 of PRP1 were synthesized. The fimbriae significantly bound peptide 130-150, immobilized on 96-well plates, and the peptide also inhibited binding of 125I-labeled fimbriae to PRP1-coated HAP beads by almost 100%. Peptides 75-89, 90-106, and 121-129, immobilized on plates, showed considerable ability to bind fimbriae. For further analysis of active sites in residues 130 to 150, synthetic peptides corresponding to residues 130 to 137, 138 to 145, and 146 to 150 were prepared. Peptide 138-145 (GRPQGPPQ) inhibited fimbrial binding to PRP1-coated HAP beads by 97%. This amino acid sequence was shared in the alignment of residues 75 to 89, 90 to 106, and 107 to 120. Six synthetic peptides were prepared by serial deletions of individual residues from the N and C termini of peptide GRPQGPPQ. Peptide PQGPPQ was as inhibitory as peptide GRPQGPPQ. Further deletions of the dipeptide Pro-Gln from the N and C termini of peptide PQGPPQ resulted in significant loss of the inhibitory effect. These results strongly suggest that PQGPPQ is the minimal active segment for binding to P. gingivalis fimbriae and that the moiety of the Pro-Gln dipeptide plays a critical role in expressing binding ability.

Bacterial Adhesion↗
PubMed1996

Excessive production of nitric oxide in rat solid tumor and its implication in rapid tumor growth.

BACKGROUND: Rapid tumor growth is caused by angiogenesis factors, growth factors, etc. We previously reported a possible connection between nitric oxide (NO) and enhanced vascular permeability in solid tumor. In the present experiment, the role of NO in solid tumor pathology was further investigated in animal tumor. METHODS: To identify NO formed in solid tumor (AH136B) implanted in the feet of rats, electron paramagnetic resonance (EPR) spectroscopy was performed directly on the frozen tumor tissue at 110K by measuring endogenous nitrosyl iron-sulfur complexes, and by using exogenously added NO capturing agents, i.e., diethyldithiocarbamate (DETC)-Fe2+ and N-(dithiocarboxy) sarcosine (DTCS)-Fe2+ complexes. Induction of inducible isoform of nosymthase iNOS mRNA was examined with reverse transcriptase-polymerase chain reaction (RT-PCR) combined with Southern blot analysis. In addition, vascular permeability was assessed by measuring extravasation of 51Cr-labeled bovine serum albumin in solid tumor. RESULTS: Strong EPR signals from NO adducts of DETC-Fe2+ and DTCS-Fe2+ as well as strong signals from NO-hemoglobin and dinitrosyl iron sulfur complex were generated by tumor. The signal height of NO-(DTCS)2-Fe2+ observed in AH136B solid tumor was increased as the tumor gained up to 1.75 g. Induction of iNOS mRNA expression was confirmed by the above methods. Enhanced vascular permeability was suppressed by NOS inhibitors N omega- monomethyl-L-arginine or S-methylisothiourea sulfate and augmented with administration of L-arginine. CONCLUSIONS: Excessive NO production by iNOS in solid tumor was identified unequivocally by EPR spectroscopy. NO formed in solid tumor can be involved in enhanced vascular permeability and increased blood flow, and hence sustain tumor growth.

Animals↗
PubMed1996

Treatment of a depressive disorder patient with EEG-driven photic stimulation.

This study examined the effects of electroencephalographic- (EEG-) driven photic stimulation on a case of depressive disorder, as measured by a psychometric test of mood states, EEG parameters, and several autonomic indices. The EEG-driven photic stimulation enhances the alpha rhythm of brain waves using photic signals, the brightness of which is modulated by a subject's own alpha rhythm. The patient was a 37-year-old businessman, who was treated for depression with medication during the 13 months prior to his first visit to our hospital. He underwent two sets of inpatient treatment sessions, comprising first 16 and then 18 treatment sessions. The treatments brought about the following changes: an improvement in general mood state, alpha rhythm increase, cardiac parasympathetic suppression, and increased skin conductance level. In addition, significant correlations between alpha rhythm increase and cardiac parasympathetic suppression or cardiac sympathetic predominance were observed with each inpatient treatment. Significant correlations between alpha rhythm increase, cardiac parasympathetic suppression, or cardiac sympathetic predominance and the improvement of general mood state were also observed. Thus, from these observations, it was concluded that the alpha enhancement induced by EEG-driven photic stimulation produced an improvement in the patient's depressive symptomatology connected with cardiac parasympathetic suppression and sympathetic predominance.

Adult↗
PubMed1996

The use of antipoliovirus monoclonal antibodies as an improved safety test for oral live poliomyelitis vaccine.

Almost all the individual preparations of poliovirus type 3 specific monoclonal antibodies showed high neutralizing antibody titres against low-titre Sabin type 3 virus with a titer of 10(2) CCID 50/25 microliters. However, the preparations failed to neutralize high-titre virus at a titre of about 10(7) CCID50/25 microliters (undiluted virus fluid). The use of pooled monoclonal antibodies, comprising two or more individual antibodies, however, showed a high neutralizing activity for the high-titre virus suspension. The results indicate that the neutralization of high-titre Sabin type 3 virus can be achieved by the use of pooled monoclonal antibodies when appropriate antibodies are present. It seems likely that neutralization by these antibodies is achieved through the recognition of different neutralizing epitopes by specific antibodies. One of the safety tests used during the production of oral poliomyelitis vaccine (OPV) is that which employs type-specific antipoliovirus rabbit sera to detect adventitious viruses in monovalent poliovirus fluid. It has, however, proved difficult to prepare sera of this nature which can completely neutralize high-titre poliovirus having no cross-reactivity against other types of poliovirus. In our studies, pooled monoclonal antibodies showed a neutralizing activity against high-titre Sabin type 3 virus about 100-fold greater than that shown by rabbit antisera. Moreover, these antibodies appear to have two further important advantage for use in testing the safety of OPV: they showed no cross-neutralizing activity against heterotypic polioviruses; and they showed no evidence inhibiting the propagation of a number of viruses of monkey and human origin.

Animals↗
PubMed1996

Relationship of substance P and gliosis in medulla oblongata in neonatal sudden infant death syndrome.

Substance P and glial fibrillary acidic protein (GFAP) immunohistochemistry was applied to the medulla of neonatal infants who died of sudden infant death syndrome (SIDS). A quantitative analysis of cells demonstrating immunoreactivity to GFAP and substance P in 15 neonatal SIDS cases revealed increased GFAP immunoreactivity in the reticular formation, the dorsal vagal nucleus, and the solitary nucleus and an increase in substance P immunoreactivity in the spinal trigeminal nucleus and the solitary nucleus as compared with that in age-matched controls. GFAP immunopositivity suggests astrogliosis which implies a pathologic insult to neurons in the area of astrogliosis. The failure of neurons in these sites to show enhanced substance P immunopositivity may indirectly indicate altered neurons. Further study of prenatal events may be of importance in clarifying the pathogenesis of neonatal SIDS.

Chi-Square Distribution↗
PubMed1996

Potentiation of nitric oxide-mediated vasorelaxation by xanthine oxidase inhibitors.

Nitric oxide (NO), now almost synonymous with endothelium-derived relaxing factor (EDRF), reacts with superoxide anion radical (O2-) and forms a potentially toxic molecular species, peroxynitrite (ONOO-). Because xanthine oxidase (XO) seems to be a major O2- -producing enzyme in the vascular system, it is important to clarify the mechanism of XO regulation of NO/EDRF. We first characterized the inhibition of XO in vitro by three types of pyrazolopyrimidine derivatives. Kinetic studies indicated that 4-amino-6-hydroxpyrazolo[3,4-d]pyrimidine (AHPP) and allopurinol competitively inhibited the conversion of xanthine to uric acid catalyzed by XO, with apparent Ki values of 0.17 +/- 0.02 and 0.50 +/- 0.03 micro M respectively; alloxanthine inhibited this conversion in a noncompetitive manner with an apparent Ki value of 3.54 +/- 1.12 microM. O2- generation in the xanthine/XO system assayed by lucigenin-dependent chemiluminescence was suppressed most strongly by AHPP in a dose-dependent fashion; allopurinol itself appears to reduce the enzyme by transfer of an electron to O2, thus generating O(2-). AHPP significantly augmented EDRF-mediated relaxation of aortic rings from both rabbits and spontaneously hypertensive rats (SHR) in a dose-dependent manner, whereas allopurinol did not affect the relaxation and only marginal potentiation of the vasorelaxation was observed with alloxanthine. Finally, iv injection of AHPP (50.4 mg/kg; 100 micromol/300 g rat) reduced the blood pressure of SHR rats to 70% of the initial pressure; this pressure is almost the blood pressure of normal rats. Allopurinol (100 micromol/300 g rat; iv) showed transient decrease in blood pressure and moderate reduction of hypertension of SHR (10%) was observed with iv injection of alloxanthine (100 mumol/300 g rat). On the basis of these results, it seems that XO regulates EDRF/NO via production of O2-.

Allopurinol↗
PubMed1995

Mitogen induced proliferation of isolated adult mouse Schwann cells.

The proliferation of neonatal Schwann cells (SCs) in response to mitogenic agents has been well analyzed in vitro, but a limited range of mitogens have been defined. We investigated whether three identified neonatal SC mitogens [glial growth factor (GGF), platelet-derived growth factor BB (PDGF-BB), and basic fibroblast growth factor (bFGF)] are required to stimulate mitosis of adult SCs. Adult SCs were isolated from mouse sciatic nerves by mechanical and chemical dissociation, following three experimental steps: 1) culturing the dissociated cells for 24 hr in 10% FCS-F12 medium, 2) culturing these cells in serum-free medium for the next 48 hr, and 3) purifying adult SCs by differential adhesion. We describe a new method for preparation of SCs from peripheral nerves of adult mouse that provides 99.5% pure SCs populations at cell yields of greater than 3 x 10(3) cells/mg of starting nerve wet weight within 5 culture days. Although mitosis of SCs in culture in response to mitogens requires the presence of serum, the complex nature of serum renders difficult a complete analysis of mitogens required for SCs DNA synthesis, so we examined the proliferating response of adult SCs to GGF, PDGF-BB, and bFGF in serum-free medium. GGF alone had mitogenicity for adult SCs in a dose-dependent manner, and synergistic activation coupling with forskolin was not observed. Neither PDGF-BB nor bFGF was mitogenic for adult SCs when used alone or with forskolin.(ABSTRACT TRUNCATED AT 250 WORDS)

Aging↗
PubMed1995

Neurovirulence test for oral live poliovaccines using poliovirus-sensitive transgenic mice.

The transgenic mice, ICR-PVRTg21, carrying the human poliovirus receptor gene, were intraspinally inoculated with oral poliovirus vaccine viruses and the viruses that had been derived from a vaccine preparation by passagings at 38 degrees. Dose-dependent incidence of paralysis was observed in the transgenic mice inoculated with any of the viruses used. All transgenic mice showing histopathological lesions in the central nervous system appeared to display clinical signs that resembled those observed in human poliomyelitis. These suggest that relative neurovirulence levels of individual virus preparations can be estimated by values of 50% paralysis dose. Indeed, the parameter correlated well with monkey lesion scores of viruses used. Histopathological changes such as degeneration of neurons resemble those displayed by monkeys and were observed in the spinal cord, medulla oblongata, and pons. Thus, the transgenic mice, ICR-PVRTg21, may become a new animal model in place of monkeys for safety testing of oral poliovirus vaccine preparations.

Animals↗
PubMed1995

Diabetes impairs DRG neuronal attachment to extracellular matrix proteins in vitro.

Attachments of dorsal root ganglion (DRG) neurons from streptozotocin (STZ)-induced diabetic and normal C57BL mice to the following substrates were evaluated in vitro: a) poly L-lysine (PL), b) PL + type I collagen (CL-I), c) PL + type IV collagen (CL-IV), d) PL + laminin (LM) and e) PL + fibronectin (FN). After 6 h in culture, there was no significant difference in the average ratio of cells adhesive to PL between the diabetic (74.9%) and normal group of mice (75.6%). In the normal group, the addition of extracellular matrix (ECM) proteins such as CL-I, CL-IV, LM and FN to PL increased the ratios of cell attachment from 75.6% to nearly 90%. In the diabetic group, however, none of these proteins improved the attachment (the ratio changed from 74.9% to nearly 70%). Survival and neurite extension of attached cells after 48 h in culture were not different between the two groups. These results suggest that the cell-surface receptors, which enable DRG neurons to bind to the extracellular matrix proteins, are impaired by diabetes, resulting in being one of the causes of diabetic neuropathy.

Animals↗
PubMed1995

Point mutations of ras and Gs alpha subunit genes in thyroid tumors.

We studied 43 thyroid tumors including 5 adenomatous goiters, 7 follicular adenomas, 22 papillary carcinomas, and 9 medullary carcinomas with regard to the presence of point mutations in the genes of Gs alpha subunit (Gs alpha), Gi2 alpha subunit (Gi2 alpha), H-ras, K-ras, and N-ras by a polymerase chain reaction-direct sequencing method. An adenomatous goiter and a follicular adenoma showed double mutations at codon 227 and 231, and 4 papillary carcinomas showed mutation at codon 231 of the Gs alpha gene. An adenomatous goiter, a follicular adenoma, and a papillary carcinoma showed a missense mutation in codon 13 of the K-ras gene. There were no such missense mutations of these G-protein or ras genes in medullary carcinomas. These data indicate that the genetic events involved in the oncogenesis of parafollicular C-cells are different from those of thyroid follicular cells, in which missense mutations of Gs alpha and ras genes seem to play important roles in tumorigenesis.

Base Sequence↗
PubMed1995

Two different pituitary adenomas in a patient with multiple endocrine neoplasia type 1 associated with growth hormone-releasing hormone-producing pancreatic tumor: clinical and genetic features.

The clinical and genetic features of a 43-year-old male patient with multiple endocrine neoplasia type 1 were reported. He developed hyperparathyroidism, a GHRH-producing pancreatic tumor, and acromegaly between 1980 and 1983. Because his pituitary gland increased in size even after resecting the GHRH-producing pancreatic tumor, transsphenoidal hypophysectomy was performed six years later. The pituitary contained two histologically-different adenomas composed of somatotroph cells and null cells. Genetic analyses revealed loss of heterozygosity on chromosome 11 in common in the pituitary adenomas, the pancreatic endocrine tumors, and a parathyroid hyperplasia. On the other hand, mutations of ras, p53, Gs alpha, and Gi2 alpha genes were not found in these tumors. The loss of the tumor suppressor gene on chromosome 11q12-13 was involved in the formation of two pituitary adenomas, two pancreatic endocrine functioning tumors, and a parathyroid hyperplasia in this patient, but the tumorigenic factors in the specific endocrine organs remain to be studied.

Acromegaly↗
PubMed1994

Three-dimensional cell aggregation enhances growth-promoting activity of NGF in adult DRG.

After removal of the connective tissues with collagenase-trypsin treatment, DRG explants without nerve fibres from mature rodents regenerated numerous neurites all around the explants in response to NGF. To observe the response in the absence of any non-neuronal cells in the ganglia, we introduced three-dimensional cell aggregates consisting of variable numbers of highly purified isolated adult DRG neurones. In this culture system, the addition of NGF to the medium increased the maximum neurite length, the number of neurites, and the cell survival rate. Furthermore, the magnitude of this effect increased with cell aggregate size. Our results suggest that the addition of NGF produces extensive neurite outgrowth in three-dimensional aggregates of matured sensory neurones in the absence of any non-neuronal cells.

Animals↗
PubMed1994

Critical period for degradation of adult rat retinal ganglion cells and their regeneration capability after axotomy.

The optic nerve (ON) in adult rats was transected intraorbitally followed by retrograde labelling of retinal ganglion cells (RGCs) with fluorescence dye (DiI). A two phase reduction of axotomized RGCs was represented in the retina until 15 days after ON transection. The critical period of RGC loss is around 7 days after axotomy. In this period, the capability of neurite regeneration from RGCs in culture was strongly intensified by ON transection. These findings indicate that the 7th day after axotomy is important for both RGC survival and regeneration.

Animals↗
PubMed1994

Absence of hemodynamic tolerance to nicorandil in patients with severe congestive heart failure.

To evaluate whether hemodynamic tolerance develops to nicorandil, a nitrate and potassium channel opener, 14 patients with chronic heart failure (CHF) were treated with nicorandil and 11 were treated with nitroglycerin (GTN). Doses of GTN or nicorandil were titrated to achieve a > or = 20% reduction in pulmonary capillary wedge pressure (PCWP) within 1 hour, and the infusion was maintained at a constant rate for 24 hours. Both groups of patients had comparable hemodynamic parameters before drug infusions were started. The fall in PCWP was identical after 1 hour infusion of either GTN or nicorandil. In the GTN group, PCWP was not significantly different from the baseline value at 12 hours; however, in the nicorandil group, PCWP remained significantly lower than the preinfusion value for 24 hours. During the study period changes in plasma atrial natriuretic peptide (ANP) concentrations paralleled and correlated with changes in PCWP (r = 0.84, p < 0.001). These findings indicate that CHF patients develop hemodynamic tolerance to GTN within 12 hours of continuous infusion, but not to nicorandil, which remained hemodynamically effective during the 24-hour period of infusion. Furthermore, plasma ANP concentration may be a useful noninvasive index of hemodynamic tolerance during GTN or nicorandil therapy in patients with CHF.

Adult↗
PubMed1994

Nerve growth factor (NGF) restores depletions of calcitonin gene-related peptide and substance P in sensory neurons from diabetic mice in vitro.

Dorsal root ganglion neurons from streptozotocin (STZ)-induced diabetic, genetic diabetic and normal mice were cultured in serum-containing media with or without nerve growth factor (NGF). The immunocytochemical analysis carried out after 1 week in culture revealed that the ratios of neurons immunoreactive to calcitonin gene-related peptide (CGRP) in NGF-free medium in the STZ-diabetic mice (average 23.2%) were significantly lower than those in the normal mice (45.1%). The ratios of neurons immunoreactive to CGRP and substance P (SP) in the NGF-free medium were also lower in the genetic diabetic mice (23.6% and 21.8%) than those in the normal ones (40.7% and 34.2%). However, treatment with NGF restored these reduced immunoreactivities in the diabetic groups in a dose-dependent manner. These results show that NGF can be effective for the diabetes-induced depletion of CGRP and SP in sensory neurons, and suggest its possible role in the prevention and improvement of diabetic sensory neuropathy.

Animals↗