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Biomedical subjects

Y Onodera

Publications and source records attributed to Y Onodera.

At least 19 recordsLinked to original sources
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

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↗
PubMed1999

Analysis of liver single photon emission computed tomography in a case of fulminant hepatic failure.

Fulminant hepatic failure is associated with a high mortality rate. Thus, accurate assessment of hepatic functional reserve and hepatic regeneration is important. We describe a 67-year-old woman who survived subacute hepatic failure. We had an opportunity to monitor the clinical course of the patient using single photon emission computed tomography (SPECT) with 99mTc-galactosyl-human serum albumin (99mTc-GSA) and frequent hematological examinations. On admission, prothrombin time was remarkably prolonged (23.1% of control). The liver uptake of 99mTc-GSA was also considerably low. She responded well to treatment. Four weeks after admission, SPECT analysis showed a dramatic increase in liver uptake of 99mTc-GSA, suggesting promotion of hepatic regeneration. Moreover, functional liver volume calculated from the SPECT data showed a marked increase at 4 weeks after admission, whereas CT scan showed no change at that point. This indicated that SPECT with 99mTc-GSA reflected functional hepatocytes more accurately than liver volume determined by CT scan, which cannot exclude nonfunctional hepatocytes. The patient's condition improved in parallel with the improvements in the indices measured by SPECT and hematological examinations. SPECT analysis is practically useful for the prompt assessment of improvement in patients with fulminant hepatic failure.

Aged↗
PubMed1999

Therapeutic efficacy of transcranial magnetic stimulation for hereditary spinocerebellar degeneration.

We applied transcranial magnetic stimulation (TMS) as a therapeutic approach for patients with spinocerebellar degeneration (SCD). The subjects were four familial SCD patients (three men and one woman) aged from 27 to 76 years old. They were genetically analysed as two spinocerebellar ataxia type 6 (SCA 6), one SCA 1, and one SCA 7. The durations of their illness ranged from 1 to 7 years. Ten consecutive magnetic pulses were delivered over the scalp corresponding to the right cerebellar hemisphere, the middle of the cerebellum and the left cerebellar hemisphere, respectively, every day for 21 days. In all patients, the time and the number of steps required for a 10 m walk examination were significantly decreased after TMS trial compared with those before TMS. The number of feasible steps in tandem gait test increased. The total length of tracing body balance for 30 seconds measured by gravinometer was significantly decreased. However, nystagmus, dysarthria or incoordination of the upper limbs did not change after TMS trial. It is of interest that the blood flow of the cerebellar hemisphere, putamen and pons were significantly increased during the TMS trial. Although we do not know the exact mechanism by which TMS improved the ataxic gait, we speculate the increase of blood flow in the cerebellum, putamen and pons takes part in the improvement. These findings suggest that TMS over the cerebellum may be an effective therapy for patients with SCD.

Adult↗
PubMed1999

[Evaluation of the liver uptake rate measured by 99mTc-GSA SPECT to assess liver function].

Whether the global liver uptake rate of 99mTc-GSA directly measured by SPECT is useful as a new index of liver function was evaluated in comparison with biochemical test results (PT%, ChE, Alb, ICG R15, KICG) and Child classification. 99mTc-GSA SPECT was performed in 157 patients with diffuse hepatic disease or hepatobiliary tumor, and two indices, namely the global liver uptake rate measured by SPECT 15 minutes after intravenous injection of 99mTc-GSA (LUS 15) and liver uptake per volume (liver uptake density) were examined. Both LUS 15 and liver uptake density were significantly correlated with biochemical test results and Child classification. In particular, close relationships between LUS 15 and ICGR15 (r = -0.720, p < 0.0001), LUS 15 and KICG (r = -0.750, p < 0.0001), and between LUS 15 and ChE (r = 0.720, p < 0.0001), indicate that LUS 15 is a useful index to evaluate liver function. Moreover, the local liver uptake rate measured by SPECT represented regional liver function and was considered a useful index to predict the function of the remnant liver after invasive treatment such as surgery.

Adult↗
PubMed1998

Cytoplasmic diversity in leaf beet cultivars as revealed by mitochondrial DNA analysis.

Mitochondrial (mt) DNA restriction fragment length polymorphisms are convenient markers for identifying cytoplasmic variation among plant cultivars. In an attempt to detect new cytoplasmic genotypes useful for sugarbeet breeding, we have compared the hybridization patterns of mtDNA from three groups of cultivated beets, viz. leaf beet, garden beet, and fodder beet. Utilized as probes were the two sugarbeet mtDNA clones that were capable of distinguishing normal fertile and different sources of male-sterile cytoplasms from one another. The analysis allowed the identification of four chondriome types among 14 leaf beet cultivars examined. Two out of the four chondriome types were found to be different from the previously described fertile or male-sterile chondriome type. Our results thus indicate that leaf beet cultivars and landraces make up the primary cytoplasmic gene pool of the sugarbeet.

Base Sequence↗