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Biomedical subjects

Y Miyata

Publications and source records attributed to Y Miyata.

At least 127 records · Page 7Linked to original sources
PubMed1997

An Alu-linked repetitive sequence corresponding to 280 amino acids is expressed in a novel bovine protein, but not in its human homologue.

A novel protein harboring a 280-amino acid region from an Alu-linked repetitive sequence (bovine Alu-like dimer-driven family) was isolated from a bovine brain S-100 fraction using monoclonal antibodies against a rat GTPase-activating protein that shares the same epitope. The protein has an apparent molecular mass of 97 kDa (p97). Western blot analysis using extracts prepared from various tissues showed p97 to be predominantly detected in brain and moderately in liver and lung. From sequence analysis of the cDNA encoding p97, it was found that the 840-base pair sequence homologous to a part of the bovine Alu-like dimer-driven family, which has never been shown to be expressed, occurs in the middle of the protein coding region. The protein also contains a pair of intramolecular repeats composed of 40 highly hydrophilic amino acids at the C terminus. Human cDNA homologous to p97 was cloned, and its nucleotide sequence demonstrates that the 840-base pair repetitive sequence and one of the intramolecular repeats are missing. We named p97 bovine BCNT after Bucentaur. These results show that bovine BCNT is a unique molecule and suggest that an analysis of the relationship between bovine bcnt and its human homologue may help further the understanding of gene organization and evolution.

Amino Acid Sequence↗
PubMed1997

Allelic variants of the human MHC class I chain-related B gene (MICB).

The human major histocompatibility complex (MHC) is located within a 4 megabase segment on chromosome 6p21.3. Recently, a highly divergent MHC class I chain-related gene family, MIC was identified within the class I region. The MICA and MICB genes in this family have unique patterns of tissue expression. The MICA gene is highly polymorphic, with more than 20 alleles identified to date. To elucidate the extent of MICB allelic variations, we sequenced exons 2 (alpha 1), 3 (alpha 2), 4 (alpha 3), and 5 (transmembrane) as well as introns 2 and 4 of this gene in 46 HLA homozygous B-cell lines. We report the identification of eleven alleles based on seven non-synonymous, two synonymous, and four intronic nucleotide variations. Interestingly, one allele has a nonsense mutation resulting in a premature termination codon in the alpha 2 domain. Thus, MICB appears to have fewer alleles than MICA, not unlike the allelic ratio between the HLA-C and -B loci. A preliminary linkage analysis of the MICB alleles with those of the closely located MICA and HLA-B genes revealed no conspicuous linkage disequilibrium between them, implying the presence of a potential recombination hotspot between the MICB and MICA genes.

Alleles↗
PubMed1997

Electrophysiological analysis of cognitive slowing in Parkinson's disease.

To analyze chronometrically the evidence for possible cognitive slowing in Parkinson's disease, we measured visual event-related potentials (ERPs) and reaction times (RTs) in 29 patients with nondemented Parkinson's disease and 19 age-equivalent normal controls during the performance of semantic discrimination tasks. The components of the N1, P2, NA, N2 and P3 and simple and GO/NOGO RTs were observed. The N2 was measured from difference waveforms, subtracting the ERPs to frequent stimuli from those to infrequent stimuli in the discrimination task. Difference waveforms were also derived to delineate NA by subtracting the ERPs in the simple RT task from those of the frequent stimuli of the discrimination task. The N2 and P3 latencies and GO/NOGO RT in patients with Parkinson's disease were significantly longer than those in the controls, although there were no differences in N1, P2 and NA latencies or simple RT between the two groups. The results are interpreted as electrophysiological signs of cognitive slowing, particularly with respect to stimulus classification and attention processes in Parkinson's disease, independent of sensory problems. As for the automatic/controlled processes, the present results suggest that the automatic processing stage associated with NA may be less impaired than the attention-controlled processing reflected by N2 in patients with Parkinson's disease.

Adult↗
PubMed1997

Binding affinity of proteins to hsp90 correlates with both hydrophobicity and positive charges. A surface plasmon resonance study.

The 90 kDa heat shock protein (hsp90) is a major cytoplasmic molecular chaperone associating with numerous other proteins including steroid receptors. Here we provide the first numerical analysis of hsp90-target associations using surface plasmon resonance. Binding affinities of histones, the "native molten globule", casein and calmodulin to hsp90 decrease in the order of Kd = 70 +/- 24, 220 +/- 70 and 1800 +/- 600 nM, respectively. Analysis of the structure of binding proteins revealed that their binding affinity depends on both hydrophobicity and positive charges making the discriminative features of hsp90 similar to those of other molecular chaperones.

Adenosine Triphosphate↗
PubMed1997

Inhibition of spinal monosynaptic reflex in newborn rats by aurintricarboxylic acid.

The effect of aurintricarboxylic acid (ATA), an inhibitor of nuclease, on glutamatergic synaptic transmission was examined electrophysiologically in the isolated spinal cords of newborn rats. Monosynaptic reflex (MSR) was depressed about 20%, 50 min after exposure to 100 microM of ATA. Pretreatment with APV, a N-methyl-D-aspartate (NMDA) type receptor antagonist, depressed MSR by about 10%, but additional application of ATA did not affect the MSR further. In contrast, the remaining MSR following treatment with DNQX, a non-NMDA type receptor antagonist, in the Mg2+-free medium was almost completely inhibited by addition of ATA. ATA depressed NMDA- but not D,L-alpha-amino-3-hydroxy-5-methyl-4-isoxalone propionic acid (AMPA)- or kainate-induced depolarization in the medium containing normal ionic composition. Thus it is concluded that the reduction of MSR by ATA is due to blockade of NMDA type but non-NMDA type glutamate receptors. The present study also confirmed the previous conclusion that Ia monosynaptic transmission in the spinal cord of the newborn rat is mediated by NMDA as well as non-NMDA type glutamate receptors.

Animals↗
PubMed1997

Characterization of the rpsL and rrs genes of streptomycin-resistant clinical isolates of Mycobacterium tuberculosis in Japan.

Mutations in the rpsL and rrs genes associated with streptomycin resistance in Mycobacterium tuberculosis clinically isolated in Japan were characterized. The rpsL genes of 172 clinical isolates were amplified by PCR and classified into two groups on the basis of MboII restriction digestion. Thirty-three out of 54 (61.1%) streptomycin-highly resistant isolates (MIC > 200 micrograms ml-1) were not digested by MboII. By contrast, the remaining 21 of 54 (38.9%) streptomycin-highly resistant isolates, all of 41 isolates with streptomycin resistance at a lower level (20 micrograms ml-1 < MIC < or = 200 micrograms ml-1), and all of 77 streptomycin-sensitive isolates, were restricted. Thus, all isolates resistant for MboII digestion showed a high level of resistance to streptomycin. Subsequently, the sequence for the rpsL and rrs genes from the 46 isolates were analysed. Eighteen out of 19 (94.7%) streptomycin-highly resistant isolates carried a mutation in any rpsL gene at position 43 or 88, or the rrs gene; 10 out of 17 (58.8%) streptomycin-resistant isolates at a lower level were confirmed to exhibit the mutation of either the mutated rpsL gene at position 88, or the rrs gene. In the total 36 streptomycin-resistant isolates, the mutation of the rpsL or rrs gene was observed in 28 streptomycin-resistant isolates, corresponding to 77.8%, whereas none of the streptomycin-sensitive isolates had mutations in either the rpsL or rrs gene.

Antibiotics, Antitubercular↗
PubMed1997

Identification of a novel HLA-B allele (B*4202) in a Saudi Arabian family with Behçet's disease.

A new HLA-B antigen, tentatively called HLA-B42AND, was identified as a B42 serologic variant in a Saudi Arabian family. DNA sequencing analysis of the second and third exon of this new B allele revealed that B42AND was identical to B*4201 except for a single T to C substitution at position 97 of exon 2. This substitution results in histidine (CAC) at codon 9 in B42AND instead of tyrosine (TAC) in B*4201. The antigen frequency of B42AND in a Saudi Arabian population was around 10%. This novel B42AND has officially been named HLA-B*4202.

Alleles↗
PubMed1997

A dynamic population model incorporating a variety of urban functions.

"This paper aims to investigate the theoretical background of Allen and Sanglier's model, slightly modifying it. We construct a dynamic two-city population model in which there are different types of urban functions in the cities. Population dynamics of both cities are expressed in terms of a system of differential equations of the logistic type, taking account of spatial interaction between them. For this model, both the existence condition and the globally asymptotic stability of the equilibrium state are theoretically explored. Then configurations of equilibrium population distribution that correspond to different combinations of the numbers of types of urban functions in two cities are also examined. Finally, some numerical simulations are done in order to supplement the theoretical considerations."

Demography↗
PubMed1997

Porphyromonas gingivalis lipopolysaccharide-stimulated bone resorption via CD14 is inhibited by broad-spectrum antibiotics.

In the present study, we examined mechanisms of Porphyromonas gingivalis lipopolysaccharide (P-LPS)-stimulated bone resorption via CD14, one of the lipopolysaccharide (LPS) receptors, and also assessed the inhibitory action of several kinds of antibiotics on the LPS-induced stimulation. First, we observed by using mouse embryonic calvarial cells that P-LPS stimulated bone resorption through the action of endogenous interleukin-1beta (IL-1beta) and interleukin-6 (IL-6) via CD14 because (i) P-LPS-stimulated expression of IL-1beta and IL-6 genes in calvarial cells was inhibited by an anti-mouse CD14 antibody, (ii) stimulated bone resorption was markedly inhibited by both IL-1beta and IL-6 antibodies, and (iii) P-LPS-stimulated bone resorption was clearly neutralized by an anti-mouse CD14 antibody. Next, we examined the effects of several kinds of antibiotics on P-LPS-stimulated bone resorption via CD14. Two of them, chloramphenicol and erythromycin, inhibited P-LPS-stimulated bone resorption in a dose-dependent manner. In an additional experiment, we observed that chloramphenicol clearly inhibited P-LPS-stimulated expression of the CD14, IL-1beta, and IL-6 genes in calvarial cells. These results suggest that chloramphenicol might be a useful antibiotic as an anti-inflammatory agent against P-LPS-stimulated periodontal destruction occurring via CD14 in periodontal disease.

Ampicillin↗
PubMed1997

Near-infrared spectroscopic method for assessing the tissue oxygenation state of living lung.

To quantify changes in tissue oxygenation of pathologic lungs, we applied a novel method using near-infrared spectroscopy (NIRs). In in vitro experiments, we assayed the effect of photon scattering on the absorption spectra of an in vitro system simulating structures of lung, which consists of test tube containing air in hematocrit tubes and red blood cell suspension with various predetermined hemoglobin concentrations. It was determined that photon scattering of the tissue containing air did not affect the absorption in the NIR region. In in vivo experiments, we tested the applicability of the NIRs technique in rat lungs under the following conditions: (1) hypoxic loading; (2) administration of an inhibitor (NaCN) of the mitochondrial respiratory chain; (3) hemorrhagic shock. We found that: (1) Changes in hemoglobin oxygenation state in the lung measured by NIRs depended on inspired oxygen concentrations; (2) NaCN-induced reduction of cytochrome oxidase a,a3 in the lung was observed; and (3) Total hemoglobin levels in the lung decreased after bleeding. Changes in the hemoglobin oxygenation state and cytochrome oxidase redox state in the lung were determined using the least-square-curve fitting for NIR absorption spectra. Our NIRs technique was capable of assessing the hemoglobin oxygenation and cytochrome oxidase redox state in the lung.

Animals↗
PubMed1997

A new synthetic steroid, osaterone acetate (TZP-4238), increases cortical bone mass and strength by enhancing bone formation in ovariectomized rats.

A new synthetic steroid, 17 alpha-acetoxy-chloro-2-oxa-4,6-pregnadiene-3,20-dione (osaterone acetate, TZP-4238), has a potent antiandrogenic and gestagenic action with virtually no estrogenic and androgenic activity in their classical target organs. In the present study, the effects of TZP-4238 on the structure, strength, and turnover of the rat long bones were examined. Female Wistar rats at 12 weeks of age were ovariectomized (OVX) and treated with TZP-4238 or 17 beta-estradiol (E2) every day for 12 weeks. TZP-4238 significantly increased the diameters and maintained bone mineral density (BMD) of the femur of OVX rats. Although the BMD of the total femur was higher in E2-treated rats than that in TZP-treated rats, E2 did not increase the diameters of the femurs. To examine the effects of TZP-4238 and E2 on the BMD of different regions of the femur, the BMD was further analyzed by dividing it into 20 regions of equal longitudinal length. E2 increased the BMD of the distal and proximal metaphysis, regions rich in trabecular bone, but had no effect on the BMD of the femoral diaphysis compared with OVX control rats. In contrast, 2.5 and 12.5 mg/kg TZP-4238 increased the BMD of the femoral diaphysis, regions rich in cortical bone, but did not affect the BMD at the distal metaphysis. In agreement with the changes in the BMD of different regions of the femur, TZP-4238 but not E2 increased the physical strength of the femoral diaphysis assessed by a three-point bending test. Histomorphometric analyses of the cross-sections of the tibia revealed that TZP-4238 increased but E2 reduced the periosteal bone formation rate compared with OVX rats. In addition, TZP-4238 caused an increase in serum bone alkaline phosphatase with only a mild and transient decrease in urinary deoxypyridinoline excretion, while E2 reduced both of these parameters. These results demonstrate that TZP-4238 increases the dimension, BMD, and physical strength of the rat long bones by enhancing cortical bone formation, while estrogen maintains trabecular BMD by inhibiting bone resorption. Because the physical strength of long bones is affected by cortical bone mass and geometry, the effect of TZP-4238 on cortical bone may have a potential for the treatment of osteoporosis with reduced cortical bone formation.

Androgen Antagonists↗
PubMed1997

[Studies on bacillary dysentery cases of overseas travellers--during 1979 to 1995].

A total of 36,780,440 overseas travellers during 1979-1995 (17 years) were quarantined at Osaka and Kansai Airport Quarantine Station, 84,777 travellers reported themselves suffer from diarrhoea. Stools from 29,587 persons were bacteriologically examined. Various enteropathogenic bacteria were isolated from 9,766 (33.0%) patients of the stools examined. Isolated species were as follows: Plesiomonas shigelloides (3,234 cases); Salmonella spp. (2,236 cases); enterotoxgenic Escherichia coli (1,621 cases); Vibrio parahaemolyticus (1,959 cases); and Shigella spp. (1,242 cases). 1,278 different Shigella strains were isolated from 1,242 cases who were thus diagnosed as bacillary dysentery patients. The suspected regions or countries for infection of these cases were analysed. The serovars and antibiotic-sensitivities of the isolated strains were examined. Colicine typing of S. sonnei strains were also done. The results can be summarized as follows. 1) The most cases (53.4%) were infected in India. 2) The percentage distribution of sub-species of the strains was as follows; S. sonnei (57.8%), S flexneri (29.8%), S. boydii (8.4%), and S. dysenteriae (4.0%), respectively. 3) The major colicine type of S. sonnei strains were type 6 and 0. 4) The percentage of Antibiotic-resistant strains of each sub-species was S. dysenteriae (92.2%), S. sonnei (89.4%), S. flexneri (87.1%), and S. boydii (84.9%), respectively. The percentage of Antibiotic-resistant strains of S. flexneri were increased annually.

Adolescent↗
PubMed1997

[A case of paraganglioma of urinary bladder in a 96-year-old female].

A 96-year-old woman was referred to our hospital with gross hematuria. Cystoscopy, computed tomography and magnetic resonance imaging revealed a submucosal bladder tumor. Incomplete transurethral resection was performed with no intraoperative complications. The histopathological diagnosis of nonmalignant paraganglioma was confirmed by immunohistochemical staining. This patient is the oldest of the 49 patients with paraganglioma of the urinary bladder reported in the Japanese literature.

Aged↗
PubMed1997

[Treatment of acute myelogenous leukemia in patients more than 80 years old].

We studied fifteen patients older than 80 years of age with acute myelogenous leukemia (AML) treated between 1984 and 1996. Among 15 cases of AML including 7 de novo cases and 8 from myelodysplastic syndrome (MDS) or hypoplastic leukemia, 14 patients had complications, including cardiovascular disease, diabetes mellitus or other malignancies. Although patients with de novo AML showed high peripheral WBC counts and higher cellularity of bone marrow than those from MDS or hypoplastic leukemia, it was difficult in some cases to distinguish these types of AML from hematological findings. Of the 6 AML cases, three had entered complete remission (CR) by a standard dose of combination chemotherapy (BHAC-DMP). One CR patient has had CR for more than 9 years now with good QOL. Among the 3 patients treated by low-dose Ara-C, one attained CR but only for a short period. Four other patients received BRM, such as G-CSF or Ubenimex, and 2 patients died without chemotherapy. Since AML at more than 80 years of age is a highly heterogenous disease, it would be reasonable to give antileukemic agents according to the individual patient's condition.

Aged↗