Biomedical subjects

S Miyata

Publications and source records attributed to S Miyata.

At least 109 records · Page 6Linked to original sources

PubMed1998

Kinetics of apoptosis in the lung of mice with allergic airway inflammation.

BACKGROUND: Apoptosis has been suggested as a means to facilitate the resolution of eosinophilic inflammation in bronchial asthma. However, the natural course of apoptosis has not been elucidated in vivo, and there is no direct evidence for eosinophilic apoptosis within lung tissue. OBJECTIVE: The purpose of this study is to clarify whether the apoptosis occurs within the lung tissue, and to define the time-course of change in apoptosis ratio during the resolution of pulmonary eosinophilic inflammation. METHODS: Ovalbumin (OVA)-sensitized Balb/c mice were challenged with aerosolized OVA. We studied apoptotic cells in the lung of OVA-sensitized mice at 1, 3, 7 and 14 days after OVA challenge by in situ detection of DNA fragmentation with deoxynucleotidyl transferase deoxyuridyl triphosphatase nick endlabelling (TUNEL) technique. Apoptotic cells also were identified by electron microscopic analysis in the lung 7 days after OVA challenge. RESULTS: The TUNEL-method revealed that eosinophils localized in the subepithelium of bronchi undergo apoptosis following OVA challenge. Electron microscopy confirmed the presence of apoptotic cells, apoptotic bodies, and macrophages ingesting apoptotic bodies within the lung tissue. The number of apoptotic cells increased concomitantly with the increase in eosinophilic infiltration for 3 days post-challenge. However, both the apoptotic cell counts and the apoptotic ratio continued to increase even after the eosinophil count peaked, indicating rather late induction of apoptosis in the lung. In addition, TUNEL-positive cells were localized in the lung for 14 days post-challenge, indicating prolonged induction of apoptosis after the OVA challenge. CONCLUSION: Our findings constitute direct evidence of eosinophilic apoptosis in situ, and display the kinetics of apoptosis in the lung of the allergic inflammation.

Animals↗

PubMed1998

Familial evidence of vasospastic angina and possible involvement of HLA-DR2 in susceptibility to coronary spasm.

An association between genetic factors and susceptibility to coronary spasm has not been proven. Because we encountered 7 patients with familial occurrence of vasospastic angina (VSA) in 3 families, the association of a genetic factor with coronary spasm was assumed. HLA typing as one of the genetic markers was performed in the 3 families, and the affected members in each family were found to share a HLA haplotype, carrying both HLA-DR52 and DQ6. This raised the possibility that one of the susceptibility genes for coronary spasm is located in the HLA region. To assess this possibility, HLA typing was performed and compared in 110 patients with VSA but without a family history of VSA (VSA group) and 55 patients with chest pain syndrome (CPS group) as control subjects. All patients underwent a provocation test for coronary spasm, and spasm was angiographically documented in the VSA group but not in the CPS group. Of all HLA antigens, the frequency of only HLA-DR2 was significantly higher in the VSA group than in the CPS group (39.1% vs 18.2%, p<0.01). The result implied that HLA-DR2 is in linkage disequilibrium with a susceptibility gene of VSA and thus is possibly involved in susceptibility to coronary spasm in some patients with VSA.

Adult↗

PubMed1998

Head-up tilt test combined with isoproterenol infusion provokes coronary vasospastic angina.

The association of the autonomic nervous system with coronary vasospasm has been controversial. The aim of the present study was to examine the involvement of the autonomic nervous system in coronary vasospasm by applying the head-up tilt (HUT) test to patients with coronary vasospastic angina. Fifteen consecutive patients with coronary vasospastic angina and without significant organic coronary stenoses underwent the HUT test. Prior to the test, coronary spasm was documented angiographically by using an intracoronary injection of acetylcholine or ergonovine. The HUT test was performed in the early morning and repeated in the afternoon if the test was positive in provoking angina pectoris and syncope or presyncope. If the test was negative, it was repeated under intravenous infusion of isoproterenol at a rate of 1-2 microg/min. The HUT test under isoproterenol infusion in the morning provoked vasospastic angina with syncope or presyncope in 9 of the 15 patients. In the test-positive group, heart rate was significantly reduced (104+/-17 beats/min to 84+/-25 beats/min, p<0.05), which preceded a reduction in systolic blood pressure (158+/-25 mmHg to 125+/-17 mmHg, p<0.001), angina attack and syncope. The HUT test without isoproterenol infusion in the morning and the HUT test in the afternoon with or without isoproterenol infusion failed to provoke angina. The heart rate reduction preceding reduced systemic blood pressure and anginal attack suggested that parasympathetic nerve excitation plays an important role in coronary vasospasm. The results also implied that the HUT test combined with isoproterenol infusion is useful for the provocation of coronary spasm.

Acetylcholine↗

PubMed1998

Mechanical stretch activates a pathway linked to mevalonate metabolism in cultured neonatal rat heart cells.

It is not certain whether activation of the Ras/mitogen-activated protein (MAP) kinase pathway is involved in cardiac hypertrophy. 3-Hydroxy-3-methylglutaryl-coenzyme A (HMG-CoA) reductase inhibitors, such as lovastatin, prevent farnesylation of the Ras protein, which is critical for Ras's membrane localization and function. Therefore, the present study was undertaken to investigate the role of the Ras pathway, which is linked to mevalonate metabolism, in the mechanism of stretch-induced myocyte hypertrophy. Myocytes isolated from 1- to 2-day-old rats were cultured at 4.1 x 10(6) cells per well in a deformable silicon dish and incubated with serum-free medium for 7 days. The cultures were stretched by 15% on culture day 4. Stretch increased the RNA/DNA ratio by 20% to 26% on culture days 5 and 6 and the protein/DNA ratio by 18% to 20% on culture days 6 and 7. Stretch accelerated rates of protein synthesis by 24% on culture day 6. Stretch increased protein kinase C (PKC) activity, MAP kinase activity, and c-fos mRNA expression. A selective PKC inhibitor, calphostin C (1 x 10(-6) M), prevented the stretch-induced increase in PKC activity, but lovastatin (7.5 x 10(-6) M) did not. Lovastatin as well as calphostin C partially but significantly inhibited the stretch-induced increases in MAP kinase activity, c-fos mRNA expression, and protein synthesis. Pretreatment with both lovastatin and calphostin C completely inhibited the increases in these variables caused by stretch. Lovastatin as well as calphostin C prevents stretch-induced cardiac hypertrophy. These results suggest that mechanical stretch may activate the Ras pathway, which is linked to mevalonate metabolism, in cultured neonatal rat heart cells.

Animals↗

PubMed1998

Comparison of calculated nasal resistance from Röhrer's equation with measured resistance at delta P150Pa.

Values of nasal resistance at delta P150Pa have been recommended by the International Standardization Committee for clinical use. However, this point seems somewhat high for quiet nasal breathing. To determine the usefulness of calculated nasal resistance at delta P150Pa from Röhrer's equation when transnasal pressure fails to reach the point, the values at delta P150Pa calculated from the method have been compared with actually measured nasal resistances at delta P150Pa by active anterior rhinomanometry with a nasal nozzle. The mean value of measured unilateral nasal resistance in 75 patients is 0.513 +/- 0.511 Pa/cm3/s on expiration and 0.335 +/- 0.193Pa/cm3/s on inspiration. The mean value of calculated nasal resistance from Röhrer's equation is 0.511 +/- 0.515Pa/cm3/s on expiration and 0.337 +/- 0.207Pa/cm3/s on inspiration. Correlations between measured and calculated nasal resistances have been assessed and are almost identical in both expiration and inspiration. Calculated nasal resistance at delta P150Pa from Röhrer's equation seems to be suitable for evaluation when transnasal pressure fails to attain the point.

Adolescent↗

PubMed1998

[Perioperative management of intracranial hemorrhage related to hematological disease].

Six patients with hematological disease complicated by intracranial hemorrhage were surgically treated in the last 2 years. In this study, in order to clarify indication for operation and perioperative management, 6 cases were classified into 2 groups. The details of each group were as follows: Group 1 was defined by the fact that the underlying hematological disease had not yet been controlled. (One case was ITP and the others were 2 AML cases). Group 2 was defined by the fact that the underlying hematological disease was well controlled. (One case was CML, one case was ATL and one case was ITP). A tendency to bleed was corrected in all patients of group 1 in the perioperative period. In the AML cases, prevention of infection was mandatory because both AML cases had been in remission, and no serious postoperative complication had occurred. The outcome of short term treatment was excellent in all but one case, in whom the recurrence of subdural hematoma caused death during the period 1 month after operation. On the other hand, no cases classified in group 2 needed specific hematological perioperative management and the short term treatment outcome was excellent. Since intracranial hemorrhage related to hematological disease has often been fatal, those patients were treated conservatively in most cases. However, from our analyses, we were able to emphasize that most intracranial hemorrhage related to hematological disease might be treated surgically and with good result, if the underlying hematological disease has entered the remission period.

Adult↗

PubMed1998

[Anticancer drug intraperitoneal chemotherapy using T-type reservoir sheet for unresectable gastric cancer].

T-type reservoir sheets (anti-adhesion sheets developed to prevent adhesions + reservoir) were intraperitoneally implanted in 16 patients with unresectable gastric cancer and postoperatively used to suction off ascitic fluid, to prevent cancerous adhesions of the intestines, and to intraperitoneally infuse anticancer drugs with a view to improving QOL and prolonging survival time. The results showed that whereas all of the patients had been class V according to intraoperative cytodiagnosis, postoperatively they were all class I-II and their ascites had either completely or temporarily resolved. Performance status (PS) improved in 14 patients (87.5%), and 14 patients (87.5%) were discharged. According to the Cancer Body Cavity Efficacy Rating Criteria (Japan Society for Cancer Therapy), CR was achieved in 10 cases, PR in 3 cases, NR in 3 cases, and the mean home care rate was 45.4%. Mean survival time to date, February 1997, is 7.8 months, two patients are alive, and the longest survival time has been 22 months. This method facilitates suctioning of ascitic fluid. It prevents irregular adhesions of the intestine, and protects against the development of ileus. It enables repeated intraperitoneal administration of high concentrations of anticancer drugs, uniformly, extensively, safely and easily. It facilitates intraperitoneal cytodiagnosis, ascitic fluid sampling, and monitoring of the efficacy of anticancer agents. The special features of this method are the high percentage of patients residing at home and the ability to administer intraperitoneal infusions of anticancer agents continually and repeatedly on an outpatient basis.

Adult↗

PubMed1998

Comparative studies on the antiplatelet effects of a humanized anti-platelet glycoprotein IIb/IIIa antibody (YM337) and ReoPro under flow conditions.

Recent clinical studies have shown that the interruption of platelet function appears to be effective for treatment of coronary occlusive diseases. For this purpose, a Fab fragment of humanized anti-platelet glycoprotein (GP) IIb/IIIa monoclonal antibody (YM 337) that exhibited an in vivo antithrombotic effect without prolongation of bleeding time in monkeys was previously characterized. In this study, the effect of YM 337 under physiological flow conditions with high or low shear rate was evaluated. The antiplatelet effects of YM 337 under varying wall shear rates were examined with the whole blood flow system. This technique allows real time visualization of the formation of fluorescence-labeled platelet thrombi on a collagen surface in a parallel plate flow chamber mounted on an epifluorescence microscope. The process of thrombus growth was also recorded in video tape and subjected to computer-assisted image analysis. We found that YM 337 displayed a high shear-preferential antiplatelet effect, while ReoPro, a control anti-GP IIb/IIIa antibody, did not show such shear dependency. The present findings therefore suggest that YM 337 might be a useful antiplatelet agent which can block pathological thrombotic events occurring under high shear, such as in coronary occlusive diseases.

Abciximab↗

PubMed1997

The calcimimetic compound NPS R-568 suppresses parathyroid cell proliferation in rats with renal insufficiency. Control of parathyroid cell growth via a calcium receptor.

Parathyroid (PT) cell hyperplasia is a common consequence of chronic renal insufficiency (CRI). NPS R-568 is a phenylalkylamine compound that acts as an agonist (calcimimetic) at the cell surface calcium receptor (CaR). To test the hypothesis that the CaR plays a role in PT hyperplasia in CRI, we tested the effect of NPS R-568 on PT cell proliferation in rats with renal insufficiency. Rats were subjected to 5/6 nephrectomy and then infused intraperitoneally with 5-bromodeoxyuridine (BrdU) to label S-phase cells. Two groups of nephrectomized rats received NPS R-568 by gavage twice daily for 4 d (1.5 and 15 mg/kg body wt). On day 5, the number of BrdU-positive PT cells of vehicle-treated nephrectomized rats was 2.6-fold greater than that of the sham-operated control. Low and high doses of NPS R-568 reduced the number of BrdU-positive PT cells by 20 and 50%, respectively. No changes in staining, however, were observed in ileal epithelial cells (CaR-negative) or in thyroidal C-cells (CaR-positive). Furthermore, the effect of NPS R-568 could not be explained by changes in serum 1,25(OH)2D3 or phosphorus. These results indicate that NPS R-568 suppresses PT cell proliferation in rats with renal insufficiency, and lend support to the linkage between the CaR and PT hyperplasia in CRI.

Aniline Compounds↗

PubMed1997

Immunohistochemical colocalization of glycoxidation products and lipid peroxidation products in diabetic renal glomerular lesions. Implication for glycoxidative stress in the pathogenesis of diabetic nephropathy.

Advanced glycation end products (AGEs) include a variety of protein adducts whose accumulation alters the structure and function of tissue proteins and stimulates cellular responses. They have been implicated in tissue damage associated with diabetic complications. To assess the possible link between AGE accumulation and the development of diabetic nephropathy (DN), we have examined the immunohistochemical localization of various AGE structures postulated to date, i.e., pentosidine, Nepsilon-(carboxymethyl)lysine (CML), and pyrraline, in diabetic and control kidneys. CML and pentosidine accumulate in the expanded mesangial matrix and thickened glomerular capillary walls of early DN and in nodular lesions and arterial walls of advanced DN, but were absent in control kidneys. By contrast, pyrraline was not found within diabetic glomeruli but was detected in the interstitial connective tissue of both normal and diabetic kidneys. Although the distribution of pyrraline was topographically identical to type III collagen, distribution of pentosidine and CML was not specific for collagen type, suggesting that difference in matrix protein composition per se could not explain heterogeneous AGE localization. Since oxidation is linked closely to the formation of pentosidine and CML, we also immunostained malondialdehyde (MDA), a lipid peroxidation product whose formation is accelerated by oxidative stress, assuming that local oxidative stress may serve as a mechanism of pentosidine and CML accumulation. Consistent with our assumption, diabetic nodular lesions were stained positive for MDA. These findings show that AGE localization in DN varies according to AGE structure, and suggest that the colocalization of markers of glycoxidation (pentosidine and CML) with a marker of lipid peroxidation reflects a local oxidative stress in association with the pathogenesis of diabetic glomerular lesions. Thus, glycoxidation markers may serve as useful biomarkers of oxidative damage in DN.

Adolescent↗

PubMed1997

Localization of germination-specific spore-lytic enzymes in Clostridium perfringens S40 spores detected by immunoelectron microscopy.

The localization of germination-specific spore-lytic enzymes, an amidase and a muramidase, in Clostridium perfringens S40 spores was examined by immunoelectron microscopy with respective antisera raised against the enzymes and a colloidal gold-immunoglobulin G complex. For both antisera, immunogold particles were visualized on the outside of the cortex of dormant spores, and they were not detected in germinated spores and decoated spores.

Antibodies, Fungal↗

PubMed1997

Taurine in rat posterior pituitary: localization in astrocytes and selective release by hypoosmotic stimulation.

Taurine, a gamma-aminobutyric acid (GABA)-like acidic amino acid, has previously been shown to be prominently localized to astrocytes in the supraoptic nucleus, the neurons of which contain only small amounts, and to have inhibitory actions on supraoptic neuronal activity. In the present study, taurine distribution in the neurohypophysis was determined by using a well-characterized monoclonal antibody against taurine itself. Preembedding immunohistochemistry was performed at light and electron microscopic levels by using diaminobenzidine and gold-substituted silver-intensified peroxidase (GSSP) methods. At the light microscopic level, the distribution pattern and cellular localization of taurine immunoreactivity corresponded to that of glial fibrillary acidic protein. Pituicyte cell bodies and processes displayed dense taurine immunoreactivity. Electron microscopic observations revealed strong taurine GSSP reactions in these neural lobe astrocytes, but weak taurine reactivity was seen within only some neurosecretory axons. High-performance liquid chromatography analyses demonstrated that in vitro hypoosmotic stimulation (reduction of 40 mOsm/kg) of isolated posterior pituitaries resulted in preferential increases in taurine release into the bathing medium without increased release of other amino acids. Conversely, tissue concentrations of taurine significantly decreased with hypoosmotic perfusion, while glutamate, glutamine, and GABA concentrations were not reduced. These results indicate that taurine is mainly concentrated in neurohypophysial astrocytes, which are known to engulf the neurosecretory axonal processes and terminals. Taurine released from pituicytes under basal and hypoosmotic conditions may act to suppress axon terminal depolarization and thereby depress release of neurohypophysial peptides.

Animals↗

PubMed1997

Nucleotide sequence analysis of the HLA class I region spanning the 237-kb segment around the HLA-B and -C genes.

To elucidate the detailed gene organization of the human leukocyte antigen (HLA) class I region on chromosome 6, seven contiguous cosmid genomic clones covering the 237-kb segment around the HLA-B and -C loci were subjected to DNA sequencing by the shotgun strategy to give a single contig of 236,822 bp from the MICA gene (58.2 kb centromeric of HLA-B) to 90.8 kb telomeric of HLA-C. This region was confirmed to contain four known genes, MICA, HLA-17, HLA-B, and HLA-C, from centromere to telomere. Further, a new member of the P5 multicopy genes was found to be about 1.3 kb upstream of the HLA-17 gene and designated P5.8. Five novel genes designated NOB1-5 were identified by RT-PCR and Northern blot hybridization. In addition, two pseudogenes, dihydrofolate reductase pseudogene (DHFRP) and ribosomal protein L3 homologous gene (RPL3-Hom), were also found in the vicinity of the HLA-B and -C genes, respectively. The two segments (about 40 kb) downstream of the HLA-B and HLA-C genes showed high sequence homology to each other, suggesting that segmental genome duplication including the major histocompatibility complex (MHC) class I gene must have occurred during the evolution of the MHC.

Blotting, Northern↗

PubMed1997

Accumulation of pyrraline-modified albumin in phagocytes due to reduced degradation by lysosomal enzymes.

Previous studies suggested that the interaction between proteins modified by advanced glycation end products (AGEs) and cells, such as macrophages, may be involved in diabetic angiopathy. Pyrraline is one of the AGEs and known to be elevated in plasma of diabetic rats and humans, and is present in vascular lesions of diabetic and elderly subjects. We examined whether modification of albumin by pyrraline influences its degradation by macrophage-like cell line, P388D1 cells. Degradation of pyrraline-modified albumin by these cells was diminished, causing accumulation of the albumin in these cells. The susceptibility of pyrraline-modified albumin to lysosomal proteolytic enzymes was reduced by approximately 40% in vitro, while lysosomal activity in the cells per se was not affected. This phenomenon was also observed when human monocytes were used instead of P388D1 cells. Our results suggest that accumulation of pyrraline-modified albumin in P388D1 cells is due to the reduced susceptibility of the protein to lysosomal enzymatic degradation. Such alterations in the interaction between AGEs-modified protein and phagocytes may contribute to angiopathy in elderly subjects and patients with diabetes.

Albumins↗

PubMed1997

Transcriptional activation of mucin by Pseudomonas aeruginosa lipopolysaccharide in the pathogenesis of cystic fibrosis lung disease.

An unresolved question in cystic fibrosis (CF) research is how mutations of the CF transmembrane conductance regulator, a Cl ion channel, cause airway mucus obstruction leading to fatal lung disease. Recent evidence has linked the CF transmembrane conductance regulator mutation to the onset and persistence of Pseudomonas aeruginosa infection in the airways, and here we provide evidence directly linking P. aeruginosa infection to mucus overproduction. We show that P. aeruginosa lipopolysaccharide profoundly upregulates transcription of the mucin gene MUC 2 in epithelial cells via inducible enhancer elements and that this effect is blocked by the tyrosine kinase inhibitors genistein and tyr-phostin AG 126. These findings improve our understanding of CF pathogenesis and suggest that the attenuation of mucin production by lipopolysaccharide antagonists and tyrosine kinase inhibitors could reduce morbidity and mortality in this disease.

Benzylidene Compounds↗

PubMed1997

Immunochemical demonstration of Eisenia tetradecapeptide, a bioactive peptide isolated from the gut of the earthworm Eisenia foetida, in tissues of the earthworm.

The quantity and localization of Eisenia tetradecapeptide which was isolated from the gut of the earthworm Eisenia foetida were examined in tissues of the same species by enzyme-linked immunosorbent assay and immunohistochemistry. Analysis by enzyme-linked immunosorbent assay showed that Eisenia-tetradecapeptide-like immunoreactivity was present in both the central nervous system (cerebral ganglion, subesophageal ganglion, ventral ganglia, and ventral nerve cord) and the gut (esophagus, crop, gizzard, and intestine). The central nervous system contained a higher amount of Eisenia-tetradecapeptide-like immunoreactivity (1.3 pmol/mg wet weight) than the gut (0.2-0.6 pmol/mg wet weight). Eisenia-tetradecapeptide-like immunoreactivity was scarcely detected in the body-wall muscle, nephridia, and sexual organs (testis, ovary, seminal vesicle, and ovisac). Immunohistochemical analysis demonstrated that intense Eisenia-tetradecapeptide-like immunopositive cells and nerve fibers were present in the central nervous system. Immunoreactivity was found in the epithelial cells lining the esophagus and in the submucous plexus in various parts of the gut. Thus, the present study suggests that Eisenia tetradecapeptide is a neuropeptide and/or peptide hormone present in both the central nervous system and the gut of the earthworm and that its role involves the regulation of gut motility.

Amino Acid Sequence↗

PubMed1997

Inhibition of gastrulation in Xenopus embryos by an antibody against a cathepsin L-like protease.

An antibody against cathepsin L-like protease (AACLP) was injected into one cell of 2-celled Xenopus embryos. The blastopores of AACLP-injected embryos either did not invaginate or failed to complete invagination. As a result of this failure to complete gastrulation, the body axes could not form normally and tail bud stage embryos were bent dorsally. Embryos injected with a control antibody (CA) developed normally through the tadpole stage. Mesodermal induction was not inhibited in embryos exhibiting this AACLP-induced gastrulation defect, but the mesodermal structure of these embryos was organized incorrectly due to the defective gastrulation during the early stages.

Animals↗

PubMed1997

Molecular characterization of a germination-specific muramidase from Clostridium perfringens S40 spores and nucleotide sequence of the corresponding gene.

The exudate of fully germinated spores of Clostridium perfringens S40 in 0.15 M KCI-50 mM potassium phosphate (pH 7.0) was found to contain another spore-lytic enzyme in addition to the germination-specific amidase previously characterized (S. Miyata, R. Moriyama, N. Miyahara, and S. Makino, Microbiology 141:2643-2650, 1995). The lytic enzyme was purified to homogeneity by anion-exchange chromatography and shown to be a muramidase which requires divalent cations (Ca2+, Mg2+, or Mn2+) for its activity. The enzyme was inactivated by sulfhydryl reagents, and sodium thioglycolate reversed the inactivation by Hg2+. The muramidase hydrolyzed isolated spore cortical fragments from a variety of wild-type organisms but had minimal activity on decoated spores and isolated cell walls. However, the enzyme was not capable of digesting isolated cortical fragments from spores of Bacillus subtilis ADD1, which lacks muramic acid delta-lactam in its cortical peptidoglycan. This indicates that the enzyme recognizes the delta-lactam residue peculiar to spore peptidoglycan, suggesting an involvement of the enzyme in spore germination. Immunochemical studies indicated that the muramidase in its mature form is localized on the exterior of the cortex layer in the dormant spore. A gene encoding the muramidase, sleM, was cloned into Escherichia coli, and the nucleotide sequence was determined. The gene encoded a protein of 321 amino acids with a deduced molecular weight of 36,358. The deduced amino acid sequence of the sleM gene indicated that the enzyme is produced in a mature form. It was suggested that the muramidase belongs to a separate group within the lysozyme family typified by the fungus Chalaropsis lysozyme. A possible mechanism for cortex degradation in C. perfringens S40 spores is discussed.

Amino Acid Sequence↗