PubMed Health⌕ Search

Biomedical subjects

Y Onodera

Publications and source records attributed to Y Onodera.

At least 19 recordsLinked to original sources
PubMed2003

Dysferlin mutations in Japanese Miyoshi myopathy: relationship to phenotype.

OBJECTIVE: To study dysferlin gene mutations and genotype-phenotype correlations in Japanese patients with Miyoshi myopathy (MM). BACKGROUND: MM is an autosomal recessive distal muscular dystrophy that arises from mutations in the dysferlin gene. This gene is also mutated in families with limb girdle muscular dystrophy 2B. METHODS: The authors examined 25 Japanese patients with MM. Genomic DNA was extracted from the peripheral lymphocytes of the patients. The PCR products of each of 55 exons were screened by single strand conformation polymorphism or direct sequencing from the PCR fragments. RESULTS: The authors identified 16 different mutations in 20 patients with MM; 10 were novel. Mutations in Japanese patients are distributed along the entire length of the gene. CONCLUSIONS: Four mutations (C1939G, G3370T, 3746delG, and 4870delT) are relatively more prevalent in this population, accounting for 60% of the mutations in this study. This study revealed that the G3370T mutation was associated with milder forms of MM and the G3510A mutation was associated with a more severe form.

Adult↗
PubMed2003

Oxidative stress and predominant Abeta42(43) deposition in myopathies with rimmed vacuoles.

This study was undertaken to determine the C terminus of amyloid beta protein (Abeta), accumulated in vacuolated muscle fibers, and compare these findings to the level of oxidative stress. Eight patients with myopathies characterized by rimmed vacuoles (RVs) were analyzed. Monoclonal antibodies specific to Abeta40 or Abeta42(43) revealed that the Abeta42(43) immunoreactivity was solely distributed in the vacuolated muscle fibers, and that only a part was also immunopositive for anti-Abeta40. Quantitative analyses in four specimens, in which eight or more vacuolated muscle fibers were observed, revealed that the mean incidence of Abeta42(43)-positive muscle fibers was 79.5+/-6.2% in total vacuolated muscle fibers, whereas that of the Abeta40-positive fibers was 42.9+/-12.6%. The predominance of Abeta42(43) deposition was statistically significant ( P<0.05). Abeta deposition was then compared with the distribution of oxidative nucleic acid damage in muscle fibers using a monoclonal antibody against 8-hydroxy-2'-deoxyguanosine and 8-hydroxyguanosine (8OHdG&G). The cytoplasmic staining for anti-8OHdG&G was found not only in vacuolated muscle fibers, but also in other muscle fibers including morphologically normal ones. Positive staining was completely abolished by RNase pretreatment and, thus, was suggested to reflect an increase of cellular RNA oxidation. The distribution of 8OHdG&G was much broader than the Abeta deposition. These data suggest that Abeta42(43) is predominantly involved in the pathogenesis of muscle fiber degeneration with RVs, and that oxidative damage may precede Abeta deposition in muscle fibers and play a key role in the pathomechanism of myopathies with RVs.

Adult↗
PubMed2002

Mutation in the caveolin-3 gene causes a peculiar form of distal myopathy.

The authors describe a patient with sporadic distal myopathy associated with reduced caveolin-3 in muscle fibers in which the muscle atrophy was restricted to the small muscles of the hands and feet. Gene analysis disclosed a heterozygous 80 G-->A substitution in the caveolin-3 gene that was identical to that of reported cases of elevated serum creatine kinase. This patient further demonstrated possible clinical heterogeneity of myopathies with mutations in the caveolin-3 gene.

Adolescent↗
PubMed2002

A novel A97P amino acid substitution in alpha-galactosidase A leads to a classical Fabry disease with cardiac manifestations.

BACKGROUND: Fabry disease results from a genetic deficiency of alpha-galactosidase A (GLA) activity. Phenotype-genotype correlations in this condition have not as yet been fully elucidated. OBJECTIVE: To report a case of a male patient with classical Fabry disease and his mother, a heterozygous female with Fabry disease, showing cardiac involvement, and to identify the underlying GLA gene mutation in this particular phenotype. PATIENTS/METHODS: Genomic DNA was extracted from the patient, his mother and the unaffected family members. Biopsy specimens of skin, heart and kidney were examined using light and electron microscopy. The mutation was identified by polymerase chain reaction and direct sequencing and was confirmed by restriction enzyme fragment length polymorphism. RESULTS: The G-->C transversion was identified in codon 97 of the GLA gene and resulted in an A97P amino acid substitution that was a novel pathogenic GLA gene mutation. The male patient who had classical Fabry disease was hemizygous and his mother was heterozygous for this mutation. CONCLUSIONS: These results indicate that the A97P amino acid substitution in GLA might tend to induce classical Fabry disease.

Adult↗
PubMed2001

Inhibitory activity of quinolones against DNA gyrase of Mycobacterium tuberculosis.

The in vitro inhibitory activities of quinolones against Mycobacterium tuberculosis DNA gyrase were measured. The 50% inhibitory concentrations (IC(50)s) of sitafloxacin (DU-6859a), sparfloxacin, ciprofloxacin and levofloxacin against supercoiling activity of DNA gyrase were 1.67, 4.80, 12.2 and 13.9 mg/L, respectively, and correlated well with their MICs. Two altered proteins of GyrA containing Ala-90Val, or Ala-90Val and Asp-94Gly were also purified and the inhibitory activities of the quinolones ranged from 12 to >83 times weaker than those against the wild-type enzyme. These results suggest that mutations in the corresponding genes confer quinolone resistance.

4-Quinolones↗
PubMed2000

A rice functional transcriptional activator, RISBZ1, responsible for endosperm-specific expression of storage protein genes through GCN4 motif.

The GCN4 motif, a cis-element that is highly conserved in the promoters of cereal seed storage protein genes, plays a central role in controlling endosperm-specific expression. This motif is the recognition site for a basic leucine zipper transcriptional factor that belongs to the group of maize Opaque-2 (O2)-like proteins. Five different basic leucine zipper cDNA clones, designated RISBZ1-5, have been isolated from a rice seed cDNA library. The predicted gene products can be divided into two groups based on their amino acid sequences. Although all the RISBZ proteins are able to interact with the GCN4 motif, only RISBZ1 is capable of activating (more than 100-fold expression) the expression of a reporter gene under a minimal promoter fused to a pentamer of the GCN4 motif. Loss-of-function and gain-of-function experiments using the yeast GAL4 DNA binding domain revealed that the proline-rich N-terminal domain (27 amino acids in length) is responsible for transactivation. The RISBZ1 protein is capable of forming homodimers as well as heterodimers with other RISBZ subunit proteins. RISBZ1 gene expression is restricted to the seed, where it precedes the expression of storage protein genes. When the RISBZ1 promoter was transcriptionally fused to the beta-glucuronidase reporter gene and the chimeric gene was introduced into rice, the beta-glucuronidase gene is specifically expressed in aleurone and subaleurone layer of the developing endosperm. These findings suggest that the specific expression of transcriptional activator RISBZ1 gene may determine the endosperm specificity of the storage protein genes.

Amino Acid Motifs↗
PubMed2000

High prevalence of spinocerebellar ataxia type 1 (SCA1) in an isolated region of Japan.

Autosomal dominant cerebeller ataxias (ADCAs) are a heterogeneous group of neurodegenerative disorders that differ in both the clinical manifestations and modes of inheritance. At present, eight different genes causing ADCAs have been found: spinocerebeller ataxia type 1 (SCA1), SCA2, SCA3/Machado-Joseph disease (MJD), SCA6, SCA7, SCA8, SCA12 and dentatorubropallidoluysian atrophy (DRPLA). The relative prevalence of each mutation varies according to race and native place. We studied 117 unrelated ADCA families that originated from the Tohoku District in the northernmost part of Honshu Island in Japan (mainly Miyagi Prefecture in the central part of Tohoku District). The SCA1 mutation was the most frequent among the known disorders (24.8% of all such families). The relative prevalence of SCA1 in the Tohoku District is very high compared with the values already reported from other regions in the world. Because the population of this area had seldom moved, the alleles with SCA1 mutations (including alleles with an intermediate CAG repeat number) are assumed to have been present in this area for a long time.

Ataxin-1↗
PubMed2000

DNA single-strand breaks are increased in muscle diseases with rimmed vacuoles.

Some pathological similarities between Alzheimer's disease and muscle diseases with rimmed vacuoles (RV) have been pointed out. For example, several pathological hallmark proteins have been reported to be immunopositive in the lesions of both diseases. Since apoptotic processes or primary DNA damage are suggested to play a role in the pathomechanism of Alzheimer's disease, we examined DNA double-strand breaks (DSB) and single-strand breaks (SSB) in the muscle biopsy specimens of several diseases, including muscle diseases with RV. Although no DSB-positive myonuclei were detected in any muscles examined, the number of SSB-positive myonuclei markedly increased in the muscles from cases with polymyositis and muscle diseases with RV. In polymyositis, SSB-positive myonuclei were observed in regenerating fibers and muscle fibers in the vicinity of inflammatory infiltrates, suggesting that the increase of SSB is due to muscle fiber regeneration following necrosis and inflammation. In muscle diseases with RV, however, SSB-positive myonuclei were observed in small angulated fibers and in morphologically normal fibers, regardless of necrosis, regeneration or inflammation. These findings suggest that muscle diseases with RV may share a common pathological process involving DNA damage.

Adolescent↗
PubMed2000

Mechanism of quinolone resistance in Staphylococcus aureus.

The resistance mechanisms to fluoroquinolones in Staphylococcus aureus were clarified by analyzing mutations in the genes encoding target enzymes, and examining the expression of the efflux pump, and determining the inhibitory activities of fluoroquinolones against the altered enzymes. Mutations in the grlA and gyrA genes of 344 clinical strains of S. aureus isolated in 1994 in Japan were identified by combinations of methods - single-strand conformation polymorphism analysis, restriction fragment length analysis, and direct sequencing - to identify possible relationships with fluoroquinolone resistance. Five types of single-point mutations and four types of double mutations were observed in the grlA gene in 204 strains (59.3%). Four types of single-point mutations and four types of double mutations were found in the gyrA gene in 188 strains (54.7%). Among these mutations, the grlA mutation of TCC --> TTC or TAC (Ser-80 --> Phe or Tyr) and the gyrA mutation of TCA --> TTA (Ser-84 --> Leu) were the principal ones, being detected in 137 (39.8%) and 121 (35.2%) isolates, respectively. A total of 15 types of mutation combinations within both genes were related to ciprofloxacin resistance (MIC greater than or equal 3.13 microg/ml) and were present in 193 mutants (56.1%). Strains containing mutations in both genes were highly resistant to ciprofloxacin (MIC50 =50 microg/ml). Those strains with the Ser-80 --> Phe or Tyr alteration in grlA, but wild type in gyrA showed a lower level of ciprofloxacin resistance (MIC50 less than or equal 12.5 microg/ml). Levofloxacin was active against 68 of 193 isolates (35.2%) with mutations at codon 80 of grlA in the presence or absence of concomitant mutations at codons 73, 84, or 88 in gyrA (MIC less than or equal 6.25 microg/ml). Sitafloxacin (DU-6859a) showed good activity in 186 of 193 isolates (96.4%), with an MIC of less than or equal 6.25 microg/ml. The contribution of membrane-associated multidrug efflux protein (NorA) expression to fluoroquinolone resistance was clarified by the checker-board titration method for determining the MIC of norfloxacin alone and in combination with carbonyl cyanide m-chlorophenylhydrazone. Among 344 clinical isolates, 139 strains (40.4%), in which the MIC of norfloxacin varied from 1.56 to >800 microg/ml, overexpressed the NorA protein. GrlA and GrlB proteins of topoisomerase IV, and GyrA and GyrB proteins of DNA gyrase encoded by genes with or without mutations were purified separately. The inhibitory activities of fluoroquinolones against the topoisomerase IV which contained a single amino acid change (Ser --> Phe at codon 80, Glu --> Lys at codon 84 of grlA, and Asp --> Asn at codon 432 of grlB) were from 5 to 95 times weaker than the inhibitory activities against the non-altered enzyme. These results suggest that the mutations in the corresponding genes may confer quinolone resistance; the active efflux pump, NorA, was considered to be the third quinolone-resistance mechanism. The numerous and complicated mutations seen may explain the rapid and widespread development of quinolone resistance described in S. aureus. Sitafloxacin showed good antibacterial activity against ciprofloxacin- or levofloxacin-resistant mutants because of its high inhibitory activity against both topoisomerase IV and DNA gyrase.

DNA Topoisomerase IV↗
PubMed2000

Quantitative nature of the Prolamin-box, ACGT and AACA motifs in a rice glutelin gene promoter: minimal cis-element requirements for endosperm-specific gene expression.

The -197 bp promoter of the rice seed storage protein gene, GluB-1, is capable of conferring endosperm-specific gene expression. This proximal 5' flanking region contains four motifs, GCN4, AACA, ACGT and Prolamin-box, which are conserved in many seed storage protein genes. We previously showed that multiple copies of GCN4 conferred endosperm expression pattern when fused to the -46 core promoter of CaMV 35S. In this paper we demonstrate, using a similar approach, that tandem repeated copies of any of the other three motifs are unable to direct expression in seeds as well as other tissues of transgenic rice plants. Mutational analysis of individual motifs in the -197 bp promoter resulted in remarkable reductions in promoter activity. These results indicate that the GCN4 motif acts as an essential element determining endosperm-specific expression and that the AACA, ACGT and Prolamin-box are involved in quantitative regulation of the GluB-1 gene. A set of gain-of-function experiments using transgenic rice showed that either the Prolamin-box or AACA, although often coupled with GCN4 in many genes, is insufficient to form a functional promoter unit with GCN4, whereas a combination of GCN4, AACA and ACGT motifs was found sufficient to confer a detectable level of endosperm expression. Taken together, our results provide direct insight into the importance of combinatorial interplay between cis-elements in regulating the expression of seed storage protein genes.

Base Sequence↗
PubMed2000

Prognostic significance of tumor grade for renal cell carcinoma.

BACKGROUND: The natural history and prognosis of renal cell carcinoma cannot be predicted. Based on the Japanese classification system, the value of nuclear grade were assessed as a possible prognostic factor for renal cell carcinomas. METHODS: In this retrospective study of 116 patients with renal cell carcinoma, radical nephrectomy was performed. Survival rates were calculated using the Kaplan-Meier method and multivariate analysis was performed using Cox's proportional hazard model. RESULTS: Distribution by stage and grade in the population of renal cell carcinomas was as follows: pT1 in 13 cases (11.3%), pT2 in 65 cases (56.5%), pT3 in 36 cases (31.3%) and pT4 in one case (0.9%) and grade 1, 28 (24.1%), grade 2, 69 (59.5%) and grade 3, 16 (13.8%). Three cases could not be determined because of pre-operative embolization of the renal cell carcinomas. Nuclear grade was correlated with stage (P=0.0002), the presence of perirenal fat involvement (P=0.003) and metastases (P=0.007). A significant difference in survival was found between grades 1 and 3 (P=0.0001) and grades 2 and 3 (P=0.0001), respectively. Survival was significantly correlated with sex (P=0.0125), tumor size (P=0.0001), the presence of lymph node metastasis (P=0.0001), renal vein involvement (P=0.0001), perirenal fat involvement (P=0.002) or distant metastasis (P=0.0001). The multivariate analysis showed that the occurrence of tumor grade (P=0.0006) or distant metastasis were independent prognostic values. CONCLUSION: The observations lead us to conclude that the nuclear grade according to the Japanese classification system appears to be of reliable prognostic value for renal cell carcinomas.

Adult↗
PubMed1999

A conspicuous adaptability to antibiotics in the Escherichia coli mutator strain, dnaQ49.

By repeating the cycle of mutagenesis and selection, the Escherichia coli dnaQ49 mutator acquired high level resistance to ampicillin (30,000 micrograms ml-1), streptomycin (26,000 micrograms ml-1) and ofloxacin (3000 micrograms ml-1). Under the strong pressure of ofloxacin, dnaQ49 also followed the history of mutations in the gyrase and topoisomerase i.v. genes previously observed in clinical isolates of quinolone-resistant E. coli. The results of these in vitro experiments suggest that naturally existing mutators may participate in the rapid acquisition of resistance to various antibiotics in patients. A possible mechanism for the occurrence of this adaptability is discussed with special reference to the property of mutagenesis accompanying DNA replication.

Amino Acid Sequence↗
PubMed1999

Dual inhibitory activity of sitafloxacin (DU-6859a) against DNA gyrase and topoisomerase IV of Streptococcus pneumoniae.

The in-vitro inhibitory activities of sitafloxacin (DU-6859a) and other quinolones against Streptococcus pneumoniae DNA gyrase and topoisomerase IV were measured. IC50s of levofloxacin, ciprofloxacin, sparfloxacin and tosufloxacin against DNA gyrase were almost three to 12 times higher than those against topoisomerase IV. On the other hand, sitafloxacin showed dual inhibitory activity against both enzymes and its IC50s were the lowest among those of the quinolones tested. These results suggest that sitafloxacin is an effective agent against pneumococcal infections and that the incidence of drug-resistant mutants is low.

Anti-Infective Agents↗
PubMed1999

Molecular cloning of the gyrA and gyrB genes of Bacteroides fragilis encoding DNA gyrase.

The genes encoding the DNA gyrase A and B subunits of Bacteroides fragilis were cloned and sequenced. The gyrA and gyrB genes code for proteins of 845 and 653 amino acids, respectively. These proteins were expressed in Escherichia coli, and the combination of GyrA and GyrB exhibited ATP-dependent supercoiling activity. To analyze the role of DNA gyrase in quinolone resistance of B. fragilis, we isolated mutant strains by stepwise selection for resistance to increasing concentrations of levofloxacin. We analyzed the resistant mutants and showed that Ser-82 of GyrA, equivalent to resistance hot spot Ser-83 of GyrA in E. coli, was in each case replaced with Phe. These results suggest that DNA gyrase is an important target for quinolones in B. fragilis.

Amino Acid Sequence↗
PubMed1999

Cloning, expression, and enzymatic characterization of Pseudomonas aeruginosa topoisomerase IV.

The topoisomerase IV subunit A gene, parC homolog, has been cloned and sequenced from Pseudomonas aeruginosa PAO1, with cDNA encoding the N-terminal region of Escherichia coli parC used as a probe. The homolog and its upstream gene were presumed to be parC and parE through sequence homology with the parC and parE genes of other organisms. The deduced amino acid sequence of ParC and ParE showed 33 and 32% identity with that of the P. aeruginosa DNA gyrase subunits, GyrA and GyrB, respectively, and 69 and 75% identity with that of E. coli ParC and ParE, respectively. The putative ParC and ParE proteins were overexpressed and separately purified by use of a fusion system with a maltose-binding protein, and their enzymatic properties were examined. The reconstituted enzyme had ATP-dependent decatenation activity, which is the main catalytic activity of bacterial topoisomerase IV, and relaxing activities but had no supercoiling activity. So, the cloned genes were identified as P. aeruginosa topoisomerase IV genes. The inhibitory effects of quinolones on the activities of topoisomerase IV and DNA gyrase were compared. The 50% inhibitory concentrations of quinolones for the decatenation activity of topoisomerase IV were from five to eight times higher than those for the supercoiling activities of P. aeruginosa DNA gyrase. These results confirmed that topoisomerase IV is less sensitive to fluoroquinolones than is DNA gyrase and may be a secondary target of new quinolones in wild-type P. aeruginosa.

4-Quinolones↗