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Biomedical subjects

S Miyoshi

Publications and source records attributed to S Miyoshi.

At least 55 records · Page 3Linked to original sources
PubMed2000

Molecular cloning and chromosomal mapping of a novel five-span transmembrane protein gene, M83.

In an attempt to identify novel transmembrane molecules expressed on hematopoietic cells, we identified a novel transmembrane protein gene, M83. Cloning of the full-length cDNAs of human and mouse M83 revealed that M83 encodes a type I transmembrane protein with a region containing five hydrophobic segments within the C-terminal part of the protein, suggesting that M83 is a five-span transmembrane molecule. The M83 protein was expressed on the cell surface as a glycosylated protein with a molecular mass of 84 kDa. The M83 gene was localized to human chromosome 16p13.3, mouse chromosome 17B1, and rat chromosome 10q12.3 distal. In human, M83 mRNA was highly expressed in placenta, pancreas, and lymphohematopoietic tissues including peripheral blood, spleen, and bone marrow. Among hematopoietic cells, it was highly expressed in resting T lymphocytes and was downregulated by cell activation, suggestive of its biological role related to the T cell resting status.

Amino Acid Sequence↗
PubMed2000

A snake venom inhibitor to muscarinic acetylcholine receptor (mAChR): isolation and interaction with cloned human mAChR.

An inhibitor to the muscarinic acetylcholine receptor (mAChR) was purified from the venom of Crotalus atrox (western diamondback rattlesnake). The inhibitor was found to be a 30-kDa homodimer protein with phospholipase A2 activity. In order to determine the subtype selectivity of the purified inhibitor, the inhibitory effect on the binding of two orthosteric antagonists, [3H]quinuclidinyl benzilate ([3H]QNB) and [3H]N-methylscopolamine methyl chloride ([3H]NMS), to five subtypes of cloned human mAChR was tested. The purified inhibitor reduced the binding of [3H]QNB and/or [3H]NMS to all subtypes of the mAChR while showing the highest inhibitory effect on the M5 subtype. The Kd values of the receptors for the antagonists were increased in the presence of the inhibitor; however, the Bmax values were not changed. The effects of the purified inhibitor on the dissociation of [3H]NMS from the receptors were also investigated. Dissociation of the antagonist was remarkably slowed down by addition of the inhibitor. These findings may suggest an allosteric action of the purified inhibitor. In addition, the present study indicates that the presence of mAChR inhibitors is quite common in snake venoms.

Animals↗
PubMed2000

Second gas effect of N2O on oxygen uptake.

PURPOSE: The concept of the second gas effect is well known, however, there have been no studies that showed the relationship between alveolar oxygen concentration and arterial oxygen tension (PaO2) after the inhalation of nitrous oxide (N2O) in humans. The purpose of this study was to examine the changes in both end-tidal oxygen fraction (F(ET)O2) and PaO2 after N2O inhalation in patients under general anesthesia. METHODS: Fifteen patients scheduled for elective orthopedic surgery were enrolled in this study. Anesthesia was maintained with the continuous infusion of propofol and with nitrogen (N2) and oxygen (O2) (6 L x min(-1), F1O2, 0.33). In all patients, the lungs were ventilated with a Servo 900C ventilator equipped with a gas mixer for O2, N2O, and N2. After obtaining baseline data, N2 was replaced with N2O maintaining FIO2 constant at 0.33. The changes in fractional concentration of O2, N2O, and N2 were continuously measured using mass spectrometer in a breath-by-breath basis. PaO2 and hemodynamic data were obtained at 1, 5, 10, 30 and 60 min after the start of N2O inhalation. RESULTS: Five minutes after N2O inhalation, F(ET)O2 increased from 0.27+/-0.01 to 0.31+/-0.02 (P<0.01) and PaO2 increased from 172.0+/-22.5 mm Hg to 201.0+/-10.3 mm Hg (P<0.01). These effects produced by N2O were observed for 30 min. CONCLUSIONS: These results confirm the concept of second gas effect of N2O on oxygen uptake in humans and provide evidence that the PaO2 increase correlated with the increase in F(ET)O2 after N2O inhalation.

Adult↗
PubMed2000

Ipsilateral recurrence frequency after video-assisted thoracoscopic surgery for primary spontaneous pneumothorax.

OBJECTIVE: We retrospectively evaluated the results of video-assisted thoracoscopic surgery for primary spontaneous pneumothorax and recurrence. METHODS: A series of 424 patients with primary spontaneous pneumothorax were treated by video-assisted thoracoscopic surgery-289 with an ipsilateral recurrent episode, 88 with persistent air leakage for 7 days or longer, 34 with a contralateral episode, 9 with hemopneumothorax, and 4 with tension pneumothorax. The commonest management was stapling of an identified bleb, undertaken in 375 patients (88.4%). Pleural abrasion was conducted in 250 (59.0%), but the abraded area was one-third or less of the thoracic cavity in 187 (74.8%). RESULTS: No operative deaths occurred. Revisional thoracotomy was required in 1 patient with postoperative bleeding and another with incomplete postoperative lung reexpansion; 26 had prolonged air leakage, but none required revisional thoracotomy. During a mean follow-up of 31.4 months, ipsilateral pneumothorax recurred in 40 patients (9.4%), with 26 (65.0%) having recurrence within 1 year postoperatively. A video-assisted thoracoscopic surgery was conducted again in 8, and thoracotomy in 14. CONCLUSIONS: The ipsilateral recurrence of primary spontaneous pneumothorax after video-assisted thoracoscopic surgery was high at 9.4%. If video-assisted thoracoscopic surgery is to be considered as a treatment for spontaneous pneumothorax, we must therefore reduce postoperative ipsilateral recurrence by training practitioners not to overlook blebs during the procedure and/or consider widening the area of pleurodesis.

Adolescent↗
PubMed2000

Characterization of the mouse interleukin-13 receptor alpha1 gene.

Interleukin (IL)-13 is a pleiotropic immune regulatory cytokine that shares structural and biological characteristics with IL-4. The receptor for IL-13 is comprised of the IL-4 receptor alpha (IL-4Ralpha) subunit and a low-affinity IL-13-binding subunit, IL-13Ralpha1. An additional receptor, IL-13Ralpha2, binds to IL-13 with high affinity, but lacks the cytoplasmic domain for signaling. In this study, we isolated the mouse IL-13Ralpha1 gene (Il13ra1) of approximately 56 kb that spans the entire coding region. The mouse Il13ra1 gene is composed of 11 exons, and shows striking similarity in genomic structure to the previously reported class I cytokine receptor genes. Motifs characteristic of the cytokine receptor family are similarly organized on the genome, including conserved cysteines, a WSxWS motif, and Box1, indicating closely related genetic evolution of the cytokine receptor superfamily. Alternative mRNA splicings were demonstrated to generate variant transcripts that encode soluble IL-13Ralpha1. The mouse Ill13ra1 gene was mapped to the proximal region of the mouse X chromosome, and was closely linked to the DXPas3 locus by interspecific backcross analysis. Il13ra1 mRNA was co-expressed with I14ra mRNA in mouse myeloid and natural killer cells on which IL-13 has been known to act, whereas the Il13ra2 mRNA was not detected in these cells, indicating that IL-13Ralpha1 is the major component of the IL-13 receptor complex in lymphohematopoietic cells.

Alternative Splicing↗
PubMed2000

Surgical results for small cell lung cancer based on the new TNM staging system. Thoracic Surgery Study Group of Osaka University, Osaka, Japan.

BACKGROUND: Operation with combined chemotherapy has been recently recommended for very early stage of small cell lung cancer without lymph node metastasis. METHODS: A retrospective study was undertaken in 91 patients who had undergone pulmonary resection for small cell lung cancer according to the new international staging system. RESULTS: The 5-year overall probability of survival was 37.1%. The 5-year survival rate was 100% for p-stage 0, 56.1% for p-stage IA, 30.0% for p-stage IB, 57.1% for p-stage IIA, and 42.9% for p-stage IIB. In the p-stage IA-IIB patients who underwent a complete resection, the 5-year survival rate of the patients treated by operation with chemotherapy was better than that of patients treated by operation alone. In addition, the 5-year survival rate of the patients who had four or more courses of chemotherapy was 80.0%. CONCLUSIONS: These results suggest that operation should be considered for p-stage IA-IIB patients and more than four courses of combined chemotherapy might be desirable in these resectable cases.

Adult↗
PubMed2000

Microbial metalloproteases and pathogenesis.

Zinc metalloproteases produced by human pathogenic microorganisms show a wide variety of pathological actions. In local infections, the proteases cause necrotic or hemorrhagic tissue damage through digestion of structural components of the ground substance, and also form edematous lesions through generation of inflammatory mediators, while in systemic infections, the proteases act as a synergistic virulence factor through disordered proteolysis of many plasma proteins. Clostridial neurotoxins, Bacteroides fragilis enterotoxin and Bacillus anthracis lethal factor are also zinc metalloproteases.

Animals↗
PubMed2000

Altered T cell development in human thymoma is related to impairment of MHC class II transactivator expression induced by interferon-gamma (IFN-gamma).

Thymoma is known to contain CD4+CD8+ T cells, indicating that neoplastic epithelial cells of thymoma have a function as thymic cortical epithelium. However, it has been shown that there is an impairment of CD4+ T cell development in thymoma and that IFN-gamma-induced HLA-DR expression on cultured thymic epithelial cells (TEC) derived from thymoma is decreased when compared with the normal thymus. MHC class II transactivator (CIITA) is known to play a critical role in IFN-gamma-induced MHC II expression. In this study, we attempted to elucidate whether CIITA is responsible for the impaired up-regulation of MHC II molecules in response to IFN-gamma in thymoma TEC. A quantitative reverse transriptase-polymerase chain reaction examination revealed that the induced level of CIITA was significantly lower in thymoma TEC than in normal TEC. The induced levels of invariant chain (Ii) and HLA-DR in thymoma TEC were correlated with CIITA expression. The proportion of CD3+ cells in the CD4+CD8- subset in thymoma was also correlated with CIITA expression. A gel mobility shift assay however, revealed translocation of STAT1 to the nucleus in thymoma as well as normal TEC. Intercellular adhesion molecule-1 was up-regulated in the thymoma TEC to a level similar to normal TEC in response to IFN-gamma. These results indicate that impaired up-regulation of HLA-DR in response to IFN-gamma results from insufficient induction of CIITA, but not from the signal from IFN-gamma receptor to the nucleus. The abnormal regulation of HLA-DR expression caused by impaired induction of CIITA may affect CD4+ T cell development in thymoma.

Adolescent↗
PubMed2000

Electrophysiologic findings of a patient with inappropriate sinus tachycardia cured by selective radiofrequency catheter ablation.

Radiofrequency catheter ablation (RFCA) for inappropriate sinus tachycardia (IST) is associated with a high recurrence rate and sometimes requires pacemaker implantation, especially after extensive ablation. We report a patient with drug-refractory IST who was successfully treated by selective RFCA to the 2 earliest activation sites. During tachycardia, the earliest atrial activation preceded the surface P wave by 50 ms or more, whereas it was only 27 ms for the rest of the right atrium after ablation. Our patient had the longest activation period during tachycardia among the reported patients. In IST patients, a longer activation time at the site of the earliest atrial activation may imply that the abnormality is confined to a small area within the sinus node and may predict the efficacy of selective RFCA.

Adult↗
PubMed2000

Reduction of the major xenoantigen on glycosphingolipids of swine endothelial cells by various glycosyltransferases.

The effect of the various glycosyltransferases on glycosphingolipids was examined, using transfected swine endothelial cell (SEC) lines. The reactivity of parental SEC to normal human serum (NHS) and Griffonia simplicifolia IB(4) (GSIB4) lectin, which binds to the Gal alpha1-3 Gal beta 1-4 GlcNAc-R (alpha-galactosyl epitope), was reduced by approximately 20% by the treatment with D-PDMP (D-threo-1-phenyl-2-decan- oylamino-3-morpholino-1-propanol), suggesting that glycosphingolipids contained by SEC have a considerable amount of the alpha-galactosyl epitope. The overexpression of two different types of glycosyltransferase, N-acetylglucosaminyl transferase III (GnT-III), as well as alpha2, 6-sialyltransferase (ST6Gal I), alpha2,3-sialyltransferase (ST3Gal III), and alpha1,2-fucosyltransferase (alpha1,2FT), suppresses the total antigenicity of SEC significantly. However, the reduction in reactivities toward NHS and GSIB4 lectin in the case of GnT-III transfectants was milder than those in other transfectants. Western blot analysis indicated that the glycoproteins in all transfectants had diminished reactivity to NHS and GSIB4 lectin to approximately the same extent. Therefore, the neutral glycosphingolipids of these transfectants were separated by thin layer chromatography, followed by immunostaining with NHS and GSIB4 lectin. The levels of the alpha-galactosyl epitope in glycosphingolipids were not decreased in the GnT-III transfectants but were in the ST6Gal I, ST3Gal III, and alpha1,2FT transfectants. These data indicate that ST6Gal I, ST3Gal III, and alpha1,2FT reduced the alpha-galactosyl epitope in both glycoproteins and glycosphingolipids, while GnT-III reduced them only in glycoproteins.

Animals↗
PubMed2000

Malignant melanoma in the thymus.

A case of malignant melanoma in the thymus is reported. Diagnostic imaging demonstrated a left anterior mediastinal mass in a patient with giant pigmented nevus without malignant change. Histologic and cytologic specimens obtained from the tumor revealed that the tumor was malignant melanoma. Surgery revealed malignant melanoma in the left lobe of the thymus. Many cell nests of pigmented nevi were observed throughout the thymus. The malignant melanoma was thought to have originated from the nevocellular nevus in the thymus. This is the first report of malignant melanoma in the thymus.

Adult↗
PubMed2000

Analysis of Vibrio mimicus clinical strains by arbitrarily primed polymerase chain reaction.

A total of 51 Vibrio mimicus clinical strains from different geographic locations were examined by arbitrarily primed polymerase chain reaction (AP-PCR). The primer VMH-3 divided them into 28 groups, although 18 groups consisted of a single strain at present. All groups had a common 1.0-kb amplification fragment. Most of the groups consisted of strains from same region, although two exceptional groups showed a few amplification fragments including strains from different regions. AP-PCR groups were not consistently associated with serogroups. AP-PCR is thought to be a valuable and easy method for the epidemiological study of V. mimicus.

DNA Primers↗
PubMed2000

Characterization of Vibrio parahaemolyticus manganese-resistant mutants in reference to the function of the ferric uptake regulatory protein.

In many bacteria, the ferric uptake regulatory protein (Fur) has a central role in the negative regulation of genes affected by iron limitation. In this study, Vibrio parahaemolyticus strains carrying mutations in the fur gene encoding Fur were isolated by the manganese selection method to assess the function of Fur in connection with alternations in the coordinate expression of the siderophore vibrioferrin (VF) and iron-repressible outer membrane proteins (IROMPs). Ten out of 25 manganese-resistant mutants constitutively produced VF and expressed at least two IROMPs irrespective of the iron concentration in the medium. PCR-direct DNA sequencing of the fur genes in these mutants identified four different point mutations causing amino acid changes. Moreover, a fur overexpressing plasmid was constructed to prepare antiserum against V. parahaemolyticus Fur. Western blotting with this antiserum revealed that the intracellular abundance of the wild-type Fur was not significantly affected by the iron concentrations in the growth medium, and that the Fur proteins of the mutant strains occurred at substantially smaller amounts and/or migrated more rapidly in sodium dodecyl sulfate-polyacrylamide gel electrophoresis than the wild-type Fur. These data afford an additional insight into the structure-function relationship of Fur and imply its involvement in the iron acquisition systems of V. parahaemolyticus, although it is yet unknown whether its action on the target genes is direct or indirect.

Bacterial Proteins↗
PubMed2000

An epidemiological study of supernumerary primary teeth in Japanese children: a review of racial differences in the prevalence.

OBJECTIVE: To clarify the prevalence of supernumerary primary teeth in Japanese children, we evaluated this prevalence in a sample of 8122 children aged 3-6 years. Furthermore, we undertook a statistical comparison of the findings of the present study with those of previous investigations on the prevalence of supernumerary primary teeth in Japanese, Chinese and Caucasian children. SUBJECTS: The subjects used in the study consisted of 8122 children aged 3-6 years (4102 boys and 4020 girls). The children were examined in kindergartens. METHODS: The prevalence of supernumerary primary teeth was recorded by visual inspection. Statistical analysis was carried out using the chi 2 test. RESULTS: Four cases of supernumerary primary teeth were found among the children examined, and thus the prevalence was 0.05%. All of the supernumerary primary teeth were located in the maxillary lateral incisor area. CONCLUSIONS: The prevalence in a sample of 8122 Japanese children was 0.05% and that in a combined sample of 65,068 Japanese children was 0.06%.

Anodontia↗
PubMed2000

[Effects of Vibrio vulnificus metalloprotease on the capillaries: pathological actions and inactivation by alpha-macroglobulin].

Vibrio vulnificus is an opportunistic human pathogen causing wound infection and septicemia, characterized by hemorrhagic and edematous damage to the skin of limbs. When injected into the dorsal skin, an extracellular metalloprotease from this vibrio (V. vulnificus protease: VVP) enhanced the vascular permeability through activation of the Hageman factor-plasma kallikrein-kinin cascade and/or stimulation of exocytotic histamine release. Additionally, VVP caused the hemorrhagic skin lesion through disorganization of the vascular basement membrane layer due to specific degradation of type IV collagen, which is known to form the backbone structure of the basement membrane. However, injected VVP was quickly inactivated by a plasma glycoprotein, alpha-macroglobulin, at a molar ratio of 1:1. This glycoprotein was leaked from the capillaries by the actions of VVP, which resulted in in situ inactivation by physical entrapment. When VVP (45,000 Da) was incubated at 37 degrees C, a 35,000 Da fragment was generated by the autocatalytic removal of a 10,000 Da C-terminal polypeptide. This N-terminal fragment showed significant proteolytic activity, however, because of a markedly decreased affinity to the protein substrates, its permeability-enhancing and hemorrhagic activity was reduced to less than 50%. These findings indicate that the C-terminal polypeptide is not essential for but promotes skin reactions caused by VVP.

Animals↗