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Y Miyata

Publications and source records attributed to Y Miyata.

At least 91 records · Page 5Linked to original sources
PubMed1999

Molecular cloning and characterization of a novel member of the MAP kinase superfamily.

BACKGROUND: Members of the MAP kinase superfamily play important roles in a wide variety of signal transduction pathways, and several members have been identified. However, the diversity and complexity of cellular responses in mammalian systems may imply existence of hitherto unidentified members of the MAP kinase superfamily. RESULTS: We report the molecular cloning and characterization of a novel member of the MAP kinase superfamily. We isolated full-length mouse and human cDNAs that encode complete open reading frames of a novel protein kinase, termed MOK. MOK consists of 419 (human) and 420 (mouse) amino acids, with a calculated molecular weight of 48kDa. MOK contains all of the protein serine/threonine kinase consensus motifs and shows a modest similarity to members of the MAP kinase superfamily and MAK and MAK-related kinase (MRK). In addition, MOK possesses a Thr-Glu-Tyr (TEY) motif in the activation loop domain, as do classical MAP kinases. MOK is widely expressed in normal tissues and organs and localizes to the cytoplasm. MOK is able to phosphorylate several known MAP kinase substrates and to undergo autophosphorylation. A mutation in the TEY motif to AEF abolished the kinase activity of MOK, and the treatment of cells with a phosphatase inhibitor, okadaic acid, enhanced the kinase activity of MOK, suggesting the existence of an upstream kinase. Phorbol ester TPA was found to stimulate the kinase activity of MOK, whereas serum stimulation, osmotic shock, or anisomycin treatment did not significantly activate MOK. CONCLUSION: These results indicate that MOK is distantly related to members of known subfamilies of the MAP kinase superfamily and can therefore be classified as a novel member.

Amino Acid Sequence↗
PubMed1999

A case report on EEG nocturnal sleep in visually impaired persons aged in their 30s and 50s.

To determine the EEG sleep structure in visually impaired persons, EEG sleep recordings were made over two or three consecutive nights on five subjects in their 30s and 50s in the laboratory or in the Welfare Center for the Blind. Sleep variables were compared to the normative data of sighted persons of comparable ages. The results indicated that the percentages of slow wave sleep in four of the five blind individuals were much less than the values of the normative data, which is in agreement with Krieger and Glick's results (1971).

Adult↗
PubMed1999

Isolation and characterization of two 20S proteasomes from the endoplasmic reticulum of rat liver microsomes.

Two new forms of proteasomes, designated as the endoplasmic reticulum (ER) membrane-associated proteasome (ERa proteasome) and ER membrane-bound proteasome (ERb proteasome), were purified to homogeneity from 0.0125 and 2.5% sodium cholate extracts, respectively, of a rat liver microsomal fraction. SDS-PAGE analysis revealed that the purified ERa and ERb proteasomes were composed of multiple subunits similar to the cytosolic 20S proteasome. However, electrophoretic, structural and immunochemical differences between the ERa, ERb and cytosolic 20S proteasomes were observed on native PAGE, two-dimensional (2D) PAGE, and immunoblot analyses. Purification of ERb from a 2.5% sodium cholate extract of the trypsin-treated microsomal fraction yielded a trypsin-modified form of ERb (tERb), which lacked the C2 subunit at least. On the other hand, no ERa proteasome was obtained from the 0.0125% sodium cholate extract of the trypsin-treated microsomes, suggesting that ERa and ERb are ER membrane-associated and -bound proteasomes, respectively. The ERa, ERb, and cytosolic 20S proteasomes exhibited similar specificities as to peptide hydrolyzing activity, although differences in their activities were noted in the presence of SDS and phospholipid. With respect to the proteolysis of protein substrates, only the ERb proteasome cleaved beta-casein, and it also degraded reduced and carboxymethylated lysozyme considerably faster than the cytosolic 20S and ERa proteasomes. Collectively our results suggest that the ERa and ERb proteasomes may play roles in intracellular proteolysis distinct from that of the cytosolic 20S proteasome.

Amino Acid Sequence↗
PubMed1999

[Bacteriological studies of traveller's diarrhoea (6). Analysis of enteropathogenic bacteria at Kansai Airport Quarantine Station from September 4th, 1994 through December 1996].

During the period of investigation from Sept. 4, 1994 to Dec, 1996, a total of 11,446,534 overseas travellers were quarantined at Kansai Airport Quarantine Station, and 22,187 voluntarily reported of episodes suffering from diarrhoea. Bacteriological examination of the stools a total of 9,299 individuals' was performed, and the following results were obtained. 1) Various enteropathogenic bacteria were isolated from 33.3% of the stools examined. Bacterial species isolated were as follows: Plesiomonas shigelloides, 2,066 cases (66.7%); Vibrio parahaemolyticus, 358 cases (11.6%); Aeromonas sobria, 360 cases (11.6%); Shigella spp., 291 cases (9.4%); Salmonella spp., 183 cases (5.9%); A. hydrophila, 126 cases (4.1%); and V. cholerae non-O1, 121 cases (3.9%). However, ETEC was not done with an object of test. 2) In 502 cases (16.2%), plural enteropathogenic bacteria were isolated from single patient, suggesting high frequency of a mixed infections. 3) From Feb. to Mar. 1995, thirteen cases cholera were found from patients who had travelled to Bali, Indonesia. Cases with enteropathogenic bacteria other than V. cholerae O1 were found without any seasonal variation. 4) The major regions where the travellers were infected with the pathogens are as follows: Vibrio spp., were from only Asia; Shigella, widely distributed but especially in India and Indonesia; P. shigelloides and Salmonella, widely distributed. 5) Among the Shigella strains, S. sonnei were isolated the most, followed by S. flexneri, S. boydii and S. dysenteriae. A strain of S. boydii provisional serovar E 16553 was isolated from a patient infected in India. 6) Among the Salmonella serovars, Salmonella Enteritidis was isolated the most frequently (49 cases, 25.7%). 7) 265 (89.2%) of 297 Shigella strains, 52 (27.2%) of 19] Salmonella strains, and 19 (95.0%) of 20 V. cholerae O1 were resistant to one or more drugs tested (SM. CP. TC. KM. ABPC. NA. OFLX). 8) All of the 20 V. cholerae O1 strains were Ogawa, E1 Tor. All of them were toxigenic strains. 9) The most frequently isolated serovar of V. parahaemolyticus was O3: K6. 89.8% of all V. parahaemolyticus strains were positive for thermostable direct hemolysin (TDH) gene, and 14.6% of them were positive for TDH-related hemolysin (TRH) gene by DNA-probe or PCR method.

Asia, Southeastern↗
PubMed1999

Definitive chemoradiotherapy for T4 and/or M1 lymph node squamous cell carcinoma of the esophagus.

PURPOSE: To investigate the efficacy and feasibility of concurrent chemoradiotherapy for locally advanced carcinoma of the esophagus. PATIENTS AND METHODS: Fifty-four patients with clinically T4 and/or M1 lymph node (LYM) squamous cell carcinoma of the esophagus were enrolled. Patients received protracted infusion of fluorouracil 400 mg/m(2)/24 hours on days 1 to 5 and 8 to 12, 2-hour infusion of cisplatin 40 mg/m(2) on days 1 and 8, and concurrent radiation therapy at a dose of 30 Gy in 15 fractions over 3 weeks. Filgrastim was prophylactically administered to 35 patients. This schedule was repeated twice every 5 weeks, for a total radiation dose of 60 Gy, followed by two courses of fluorouracil (800 mg/m(2)/24 hours for 5 days) and cisplatin (80 mg/m(2) on day 1). RESULTS: There were 21 patients with T4M0 disease, one with T2M1 LYM, 17 with T3M1 LYM, and 15 withT4M1 LYM. Forty-nine patients (91%) completed at least the chemoradiotherapy segment. The 18 patients (33%) who achieved a complete response included nine (25%) of the 36 with T4 disease and nine (50%) of the 18 with non-T4 disease. Major toxicities were leukocytopenia and esophagitis; there were four (7%) treatment-related deaths. Prophylactic filgrastim reduced the incidence of grade 3 or worse leukopenia without improving dose-intensity or response. With a median follow-up duration of 43 months, median survival time was 9 months. The 3-year survival rate was 23%. CONCLUSION: Despite its significant toxicity, this combined modality seemed to have curative potential even in cases of locally advanced carcinoma of the esophagus.

Adult↗
PubMed1999

Dfrizzled-3, a new Drosophila Wnt receptor, acting as an attenuator of Wingless signaling in wingless hypomorphic mutants.

In Drosophila, two Frizzled proteins, Frizzled and Dfrizzled-2, have been reported to serve as receptors of Wingless. Here, we identified the third member of the Drosophila Frizzled family (Dfrizzled-3). In contrast to Dfrizzled-2, Dfrizzled-3 was transcriptionally upregulated by Wingless signaling. Although Dfrizzled-3 was capable of binding to Wingless in vitro, Wingless-dependent Armadillo/beta -catenin stabilization occurred much less effectively in Drosophila cells transfected with Dfrizzled-3 than in those with Dfrizzled-2. Flies lacking Dfrizzled-3 activity were viable and fertile, with few morphological defects. Genetic and immunochemical analysis indicated that the absence of Dfrizzled-3 activity suppresses the effects of hypomorphic wingless mutations such as failure of wing and antenna formation and restores target gene expression to the normal levels without change in wingless expression. Wingless signaling may thus be attenuated by Dfrizzled-3 at least in wingless hypomorphic mutants.

Amino Acid Sequence↗
PubMed1999

[Child neurology and neuronal apoptosis: introductory remarks].

Apoptosis is one type of cell death characterized morphologically by nuclear condensation and shrinkage of cell bodies. Thus, it is completely different from necrosis in features. Recently, it is suggested that apoptosis occurs in some neurodegenerative diseases of childhood as well as adulthood. Therefore, it is very important to reveal mechanisms of neuronal apoptosis. To the end, it is expected that new therapies will be developed to prevent the progress of neurodegenerative diseases. Based on such expectation, this symposium was organized to present recent progress in neuronal apoptosis research.

Apoptosis↗
PubMed1999

[A case of successful reoperation for aortic root pseudoaneurysm ruptured into right ventricle after modified Bentall operation].

The patient was a 51-year-old man with Marfan syndrome who had simultaneously undergone modified Bentall operation (Carrel patch method) and coronary artery bypass grafting. Prosthetic valve endocarditis (PVE) occurred 19 months after the operation. PVE had thereafter been treated by antibiotic therapy for 3 months, but echocardiography revealed prosthetic valve detachment and aortic root pseudoaneurysm ruptured into the right ventricle which appeared to have been caused by PVE. At reoperation there were no laboratory or intraoperative findings indicative of ongoing inflammation or infection. The composite graft, therefore, didn't require replacing, and it was possible to simply re-suture the composite graft and directly close the tear. The postoperative course has been uneventful with no further evidence of endocarditis.

Aneurysm, False↗
PubMed1998

Prominent expression of glial cell line-derived neurotrophic factor in human skeletal muscle.

Glial cell line-derived neurotrophic factor (GDNF) has been shown to exert neurotrophic effects on motor neurons as well as mesencephalic dopaminergic neurons. Because GDNF promotes survival of motor neurons in vivo and in vitro and rescues motor neurons from naturally occurring cell death, the potential use of GDNF for treatment of motor neuron diseases has been a major focus of recent research. The expression of GDNF in humans, however, has not been fully examined. In the present study, we examined the expression of GDNF in adult human muscle by Northern blot, reverse transcriptase polymerase chain reaction (RT-PCR), and immunohistochemical analyses to address physiological roles of GDNF in humans. Northern blot analysis demonstrated high expression of GDNF mRNA in human skeletal muscle when compared to that of mouse. Intense GDNF immunoreactivity was observed in the vicinity of plasma membranes of skeletal muscle, particularly at neuromuscular junctions. GDNF immunoreactivity was also observed within the axons and surrounding Schwann cells of peripheral nerves. However, RT-PCR detected expression of GDNF mRNA only in skeletal muscle, and not within the anterior horn cells of human spinal cord. These results suggest that GDNF is produced by skeletal muscle and taken up at the nerve terminals for retrograde transport by axons. Thus, GDNF in human skeletal muscle may be involved in promoting motor neuron survival as a target-derived neurotrophic factor.

Adult↗
PubMed1998

Up-regulation of glial cell line-derived neurotrophic factor (GDNF) expression in regenerating muscle fibers in neuromuscular diseases.

Glial cell line-derived neurotrophic factor (GDNF) has been shown to exert a target-derived trophic factor for motor neurons. Immunohistochemical analyses revealed that expression of GDNF in regeneration muscle fibers was up-regulated in polymyositis (PM) and Duchenne type muscular dystrophy (DMD). Reverse transcriptase polymerase chain reaction (RT-PCR) analyses showed that the full length GDNF was up-regulated in PM and DMD muscle; normal muscle exhibited mostly truncated GDNF. The results indicate that the GDNF expression is regulated in regeneration of human skeletal muscle.

Cells, Cultured↗
PubMed1998

Antimutagenic structural modification of quinoline assessed by an in vivo mutagenesis assay using lacZ-transgenic mice.

Quinoline, a hepatocarcinogen, mutates the bacterial tester strains in the presence of the rat liver microsomal enzymes and induces GST-P (placental glutathione S-transferase)-positive foci in a medium-term bioassay system for hepatocarcinogenesis. On the other hand, 3-fluorinated quinoline was neither mutagenic nor carcinogenic in the same assay systems, whereas, 5-fluoroquinoline was mutagenic and carcinogenic. Quinoline was recently demonstrated to be mutagenic in an in vivo mutagenicity assay system using the lacZ-transgenic mouse (MutaMouse). The present study was undertaken to know whether 3-fluoroquinoline would be devoid of in vivo mutagenicity in MutaMouse. Quinoline and 5-fluoroquinoline were also tested in the same system. Mutagenicity was evaluated in the liver, the target organ of quinoline carcinogenesis, and also in the bone marrow and testis. The results strongly indicate that fluorine-substitution at the position-3 of quinoline could be an anti-genotoxic structural modification of quinoline in a wide range of its genotoxic end-points.

Animals↗
PubMed1998

In vivo mutagenesis by the hepatocarcinogen quinoline in the lacZ transgenic mouse: evidence for its in vivo genotoxicity.

Quinoline is carcinogenic to the liver of rats and mice and mutagenic to bacterial tester strains in the presence of rat liver microsomal enzymes. The unscheduled DNA synthesis (UDS) study suggested that quinoline might be a non-genotoxic carcinogen because of the lack of UDS-inducing capacity. In order to determine whether or not cancer induction is initiated by mutagenic DNA lesions, the present study was undertaken to evaluate the mutagenicity of quinoline in an in vivo mutation assay system using the lac Z transgenic mouse (Muta Mouse). Mutation was only induced in the liver, the target organ of carcinogenesis by quinoline, but not in the other organs examined, i.e. lung, kidney and spleen. Mutant frequency in the liver was 4-fold higher than in the untreated control animals. Dimethylnitrosamine, used as a positive control, induced mutation at a frequency 5-fold higher in the liver and 3-fold higher in the spleen than in their respective control organs. It can be concluded that the genotoxicity of quinoline is responsible for its hepatocarcinogenesis, although UDS was not induced under the conditions previously reported.

Animals↗
PubMed1998

[Coronary artery bypass grafting in cases with poor left ventricular function].

From January 1987 through June 1992, 18 patients with poor left ventricular function (left ventricular ejection fraction [LVEF] less than 0.3) underwent elective isolated primary coronary artery bypass surgery. The mean age was 56.4 years (range, 46 to 72 years), and 15 were males and 3 were females. Mean pre-operative LVEF measured by ventriculography was 0.26 +/- 0.03 (range, 0.19 to 0.30). Sixteen patients (88.9%) had a prior myocardial infarction and 9 (50%) had a history of congestive heart failure. Complete revascularization was the goal for all patients, and the mean number of bypass grafts was 3.0 +/- 0.8 per patient. The left anterior descending coronary artery (LAD) was revascularized in all patients. There were no operative deaths. Post-operative LVEF improved significantly from 0.26 +/- 0.03 to 0.42 +/- 0.11 (p = 0.0002), and the regional left ventricular wall motion improved in the diaphragmatic and posterobasal regions (p < 0.01). The patency of the grafts was 93.9% in all, and 100% for LAD. The mean follow-up period was 77 months, and the overall actuarial survival rate was 88.9% at 10 years. During follow-up periods, two patients died of congestive heart failure (CHF), and two required three rehospitalizations because of CHF. The overall cardiac event free rate was 75.8% at 10 years. In patients with poor left ventricular function, surgical revascularization can be performed safely, but congestive heart failure sometimes occurs during follow-up periods and may be the cause of death. Therefore alternate forms of therapy such as cardiac transplantation and/or TMLR should be considered in selected patients.

Aged↗
PubMed1998

Expression of bcl-2 homologue mRNAs in rat liver allograft: rejection-induced cell apoptosis is associated with upregulation of bax and bcl-xs expression.

Apoptosis is considered to play an important role in rejection of organ transplants, although the precise mechanism has not been elucidated. In this study, we screened for the expression of bcl-2 homologues (bcl-2, bax, bcl-xl, and bcl-xs) and Fas ligand (FasL) by RT-PCR method in grafts during acute rejection in rats following liver transplantation. Both bax and bcl-xs (inducers of apoptosis) mRNA levels increased steadily in the allografted group from postoperative day (POD) 2 to 8, while no remarkable changes of bcl-2 and bcl-xl expression (inhibitors of apoptosis) were recognized. Significant induction of FasL gene expression was observed in the allografted group on POD 4 and expression gradually decreased thereafter, although minimal FasL mRNA expression was seen in isografts. Our results indicated, for the first time, that rejection-induced cell apoptosis is closely associated with upregulation of bax and bcl-xs expression besides FasL, but not with down-regulation of bcl-xl.

Animals↗
PubMed1998

Effect of FTY720 on immunoregulation in concordant xenotransplantation.

The present study was designed to analyze the immunosuppressive activity of FTY720 in concordant xenotransplantation. When T and B lymphocytes of human peripheral blood were incubated with FTY720, the number of viable cells decreased in a dose-dependent manner at doses higher than 4 x 10(-5) M. DNA fragmentation was observed at doses higher than 1 x 10(-5) M in T cell-rich fractions and at doses higher than 4 x 10(-5) M in B cell-rich fractions. These data demonstrate that FTY720 is cytotoxic to B lymphocytes as well as T lymphocytes and apoptosis may play an important role in this cytotoxicity. Golden Syrian hamsters were the donors and Lewis rats the recipients of skin grafts. The recipients were divided into the following four groups: (1) untreated recipients, (2) FTY720 (5 mg/kg per day) was administered orally for 8 days (days-1-6), (3) FK506 (1 mg/kg per day) was injected i.m. for 7 days (days 0-6), and (4) FK506 (1 mg/kg per day) was injected i.m. for 7 days (days 0-6) and FTY720 (5 mg/kg per day) was administered orally for 8 days (days-1-6). The mean graft survival times in groups 1-4 were 9.7 +/- 0.52 days (n = 6), 12.0 +/- 0.71 days (n = 6), 13.2 +/- 1.6 days (n = 6), and 37.7 +/- 4.3 days (n = 6), respectively. There was a significant difference in the mean survival time between groups one and four. Combined therapy with FTY720 and FK506 is a useful tool for immunoregulation in xenotransplantation.

Animals↗