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T Yakushiji

Publications and source records attributed to T Yakushiji.

At least 19 recordsLinked to original sources
PubMed2006

Observation of strong low-lying E1 strength in the two-neutron halo nucleus 11Li.

An exclusive measurement has been made of the Coulomb dissociation of the two-neutron halo nucleus 11Li at 70 MeV/nucleon at RIKEN. Strong low-energy (soft) E1 excitation is observed, peaked at about Ex = 0.6 MeV with B(E1) = 1.42(18) e2fm2 for Erel < or = 3 MeV, which was largely missed in previous measurements. This excitation represents the strongest E1 transition ever observed at such low excitation energies. The spectrum is reproduced well by a three-body model with a strong two-neutron correlation, which is further supported by the E1 non-energy-weighted cluster sum rule.

Journal Article↗
PubMed2001

Analysis of the ANA gene as a candidate for the chromosome 21q oral cancer susceptibility locus.

Loss of heterozygosity (LOH) on the long arm of chromosome 21 (21q) is observed in several human malignancies. We identified novel tumour suppressor loci on this region in primary oral squamous cell carcinomas (OSCCs). To further determine the role of 21q deletions in oral cavity tumorigenesis, 63 OSCCs were examined for LOH at 21q using 7 microsatellite markers. LOH was observed in 32 of 63 cases (50.8%) that were informative for at least one of the loci analysed. Two distinct deleted regions were identified at chromosomal region 21q11.1. The possible involvement of ANA (abundant in neuroepithelium area), a candidate tumour suppressor gene (TSG) located on 21q11.2--21.1, was also evaluated for 20 OSCCs and 9 OSCC-derived cell lines. 60% of tumours (12/20) and 88.9% (8/9 cell lines) showed absent or reduced mRNA gene expression; only one OSCC case had a nucleotide substitution in the ANA gene. Interestingly, the frequency of the suppressed ANA mRNA expression was greater in stage IV tumours than in earlier stages. In addition, re-expression of the ANA gene mRNA was induced in 4 cell lines after treatment with 5-aza-2'-deoxycytidine, a DNA demethylating agent. These findings demonstrate that there may be at least 2 distinct TSGs on 21q11.1; loss of ANA gene expression could be involved in the progression of human OSCC; and aberrant methylation of the ANA gene promoter may participate in the transcriptional silencing of the gene in oral cancer cells.

Azacitidine↗
PubMed2001

Frequent allelic loss/imbalance on the short arm of chromosome 3 in tongue cancer.

Frequent allelic imbalances including loss of heterozygosity (LOH) and microsatellite instability (MSI) on the short arm of chromosome 3 (3p) have been found in several types of human cancer. This study was designed to identify the tumor suppressor locus (or loci) on 3p associated with tongue squamous cell carcinoma (SCC). Among 16 patients with tongue SCC tested, 7 (44%) of 16 informative cases showed LOH at one or more loci. Deletion mapping of these 16 tumors revealed two discrete, commonly deleted regions on the chromosome arm. Our data support the notion that tumor suppressor gene(s) contributing to the progression of tongue squamous cell carcinoma reside on 3p24 and 3p25.

Carcinoma, Squamous Cell↗
PubMed2001

Analysis of a role for p16/CDKN2 expression and methylation patterns in human oral squamous cell carcinoma.

The p16/CDKN2 (cyclin dependent kinase number 2) gene is known to be one of the negative regulators of the cell cycle. Aberrant 5'CpG island methylation is one of the most important mechanisms of p16/CDKN2 gene promoter region alteration. We studied 8 oral squamous cell carcinoma cell lines and 25 primary tumor tissues for the p16/CDKN2 gene and its expression by PCR-SSCP, MSP, RT-PCR, and immunohistochemical methods to determine the mechanism and the potential biological significance of p16/CDKN2 gene inactivation. In primary tumors, no p16/CDKN2 gene mutations were found by PCR-SSCP. However, hypermethylation of the CpG sites of p16/CDKN2 gene was observed in 48% (12/25) cases of primary tumors and in 50% (4/8) of cell lines. To verify the p16 mRNA expression, we employed RT-PCR and observed decreased or lacked p16 mRNA in 44% (11/25) of primary tumor tissues. In addition, hypermethylation was observed in 6 of the above 11 cases (55%). An immunohistochemistry assay was also performed with the primary tumor tissues, and a semi-quantitative method was used to evaluate the staining intensity of p16 protein. We observed 52% (13/25) negative nuclear staining. When we compared these results with clinicopathological stages, there was no statistical significance. These findings suggest that hypermethylation of p16/CDKN2 promoter region may be associated with p16/CDKN2 gene alteration.

Aged↗
PubMed2000

Capacity for epithelial differentiation in synovial sarcoma: analysis of a new human cell line.

AIM: To analyse the capacity for epithelial differentiation in synovial sarcoma using a new human cell line. METHODS: A new human cell line, KU-SS-1, was established from a monophasic, spindle cell type of synovial sarcoma by grafting those cells on to severe combined immunodeficient (SCID) mice and then transferring them to in vitro culture systems. The KU-SS-1 cells were characterised by light and electron microscopy, and by immunohistochemical, flow cytometric, and cytogenetic analysis. RESULTS: Primary tumour and cultured cells at passage 20 showed a positive reaction for vimentin, which is a mesenchymal marker. After 40 passages, subcultured cells were injected into SCID mice to induce further tumours. These advanced subcultured cells and the tumour cells that they induced were positive for cytokeratin, an epithelial marker, and exhibited epithelial ultrastructural features such as intermediate junctions. Furthermore, two colour immunofluorescent analysis for proliferating nuclear cell antigen (PCNA) and intermediate filaments showed that a large number of PCNA expressing cells were positive for vimentin, and that part of this fraction also expressed cytokeratin. The existence of cells with reactivity for these three markers indicated that, in this cell line, a fraction with high proliferating capacity had both mesenchymal and epithelial markers. In addition, cytogenetically, this cell line expressed the SYT-SSX chimaeric transcript as a result of the t(X;18) (p11;q11) translocation. CONCLUSIONS: A human synovial sarcoma cell line was established and stably maintained in cell culture for more than 70 passages. In addition, this cell line showed epithelial differentiation, which supports the hypothesis that synovial sarcoma is a carcinosarcoma like tumour with true epithelial differentiation. This cell line will be a useful tool for investigating the nature of this tumour and will contribute to clinical studies.

Adult↗
PubMed1997

Characterization of the K+ current mediated by 5-HT1A receptor in the acutely dissociated rat dorsal raphe neurons.

The action of 5-hydroxytryptamine (5-HT) via the 5-HT1A receptor on dissociated rat dorsal raphe neurons was characterized under the whole-cell mode by using the nystatin-perforated patch-clamp technique. Under voltage-clamp conditions, 5-HT induced an inwardly rectifying K+ current (I5-HT) in a concentration-dependent manner. I5-HT was mimicked by 8-OH-DPAT and buspirone, which are both 5-HT1A receptor agonists. I5-HT was reversibly blocked by such 5-HT1A receptor antagonists as (S)-UH-301 a 5-HT4 receptor antagonist. I5-HT was antagonized concentration-dependently by such K+ channel blockers as quinine, Ba2+ and 4-aminopyridine but was relatively insensitive to both CS+ and tetraethylammonium. When the neurons were loaded with guanosine 5'-O-3-thiotriphosphate through a patch pipette, the K+ current induced by 5-HT became irreversible. N-ethylmaleimide (NEM), a sulfhydryl alkylating agent, irreversibly blocked I5-HT. The intracellular perfusion with 1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid (BAPTA), a Ca2+ chelator, or neomycine, a phospholipase C inhibitor, never significantly affected the 5-HT-induced response. 12-Myristate 13-acetate diester (PMA), a protein kinase C (PKC) activator, had only a weak inhibitory effect on I5-HT, and staurosporine, a PKC inhibitor, failed to significantly occlude I5-HT. Therefore, the K+ conductance activated via the 5-HT1a receptor of dorsal raphe neurons was thus characterized by the sensitivity to such K+ channel blockers as quinine, Ba2+ and 4-aminopyridine. Moreover, G protein which is NEM-sensitive and can couple to the 5-HT1A receptor, is thus considered to activate the inwardly rectifying K+ conductance without being mediated by such second messengers as Ca2+ and PKC.

Animals↗
PubMed1994

Characterization of the currents induced by sigma ligands in NCB20 neuroblastoma cells.

Electrical and pharmacological properties of currents induced by compounds having affinities for putative sigma receptors were investigated with NCB20 cells by use of the whole-cell patch-clamp technique. Antipsychotics and naloxone induced inward currents with a decrease in membrane conductance at a holding potential of -60 mV. The rank order of potency for compounds inducing these currents was bromperidol > haloperidol > mosapramine = clocapramine > carpipramine > chlorpromazine > remoxipride > naloxone. Sulpiride, which does not have affinity for sigma receptors, induced inward currents only slightly. Haloperidol-induced currents were not affected by the pretreatments with 10 microM of sulpiride, dopamine, atropine, N-methyl-D-aspartate, 2-amino-7-phosphonoheptanoic acid, morphine or A23187, 100 nM of ICS 205-930, 100 microM of forskolin, 1 microM of phorbol-12,13-dibutyrate, or 100 ng/ml of cholera or pertussis toxins. The reversal potential of the currents induced by haloperidol, naloxone or remoxipride was dependent on the concentration of external or internal potassium. These results indicate that the currents induced by the tested compounds are due to blockade of tonic, outward potassium currents and suggest that these agents act on putative sigma receptors and that the second messenger systems within the cell are not essential for the coupling between the receptors and the channels.

Animals↗
PubMed1993

Quinolone antimicrobial agents substituted with morpholines at the 7-position. Syntheses and structure-activity relationships.

A series of novel 7-substituted 1-cyclopropyl-6,8-difluoro-1, 4-dihydro-4-oxo-3-quinolinecarboxylic acids have been prepared and tested for antibacterial activities and for convulsive activities in combination with nonsteroidal antiinflammatory drug. Structure-activity relationships revealed that 7-(2-(aminomethyl)morpholino) derivative 28 had a better Gram-positive activity than the reference quinolones, such as ciprofloxacin, norfloxacin, and ofloxacin. Its Gram-negative activity was equipotent with those of norfloxacin and ofloxacin but was inferior to that of ciprofloxacin. In mouse systemic infection models, 28 showed an excellent therapeutic efficacy which might result from the potent antibacterial activity and suitable physicochemical properties. Convulsive activities of 7-morpholino derivatives in combination with nonsteroidal antiinflammatory drug fenbufen or its metabolite biphenylacetic acid markedly diminished as compared to those of 7-piperazino derivatives in the electrophysiological, biochemical, and behavioral experiments. These results suggest that 28 (Y-26611) is a novel quinolone with reduced neurotoxic excitatory adverse reaction.

4-Quinolones↗
PubMed1993

Immunochemical characterization of the carbohydrate antigens of serotype c/Lancefield group C "Streptococcus milleri".

Carbohydrate antigens of the serotype c/Lancefield group C "Streptococcus milleri" were extracted by autoclaving whole cells of the type c reference strain K51Y. The type c and group C antigen molecules were separated and partially purified by a DEAE-Sephadex A-25 column chromatography followed by Sephadex G-100 gel filtration. The purified type c antigen and group C antigen were homogeneous in the double diffusion and in the immunoelectrophoresis. The type c antigen was composed principally of glycerol, rhamnose, glucose and N-acetylglucosamine in a molar ratio of 0.22:0.27:1.00:0.48. The quantitative precipitin inhibition test indicated that N-acetylglucosamine played a major role in immunodeterminant structure. Thus, the type c antigen of "S. milleri" is a new carbohydrate type antigen and is immunochemically different from the Ottens-type antigen III found occasionally in group C streptococci. In contrast, the group C antigen preparation contained a high proportion of N-acetylgalactosamine in addition to glycerol, rhamnose, glucose and N-acetylglucosamine, and the N-acetylgalactosamine residue was involved in the immunodominant epitope, being in good agreement with the previously proposed chemical structure of the group antigen. N-acetylgalactosamine was detected in the autoclaved extracts of a nontypeable/group C strain but not of a type c/ungroupable strain.

Acetylglucosamine↗
PubMed1993

Differential properties of type I and type II benzodiazepine receptors in mammalian CNS neurones.

1. The effects of benzodiazepine receptor (BZR) partial agonists, Y-23684 and CL218,872, were compared with its full agonist, diazepam, on gamma-aminobutyric acid (GABA)-induced Cl- current (ICl) in acutely dissociated rat cerebral cortex (CTX), cerebellar Purkinje (CPJ) and spinal ventral horn (SVH) neurones, by the whole-cell mode patch-clamp technique. 2. The GABA-induced responses were essentially the same in both SVH and CPJ neurones, but the KD value of the GABA response in CTX neurone was lower than those in the other two brain regions. 3. Enhancement of the GABA response by the two partial agonists was about one-third of that by diazepam in the SVH neurones (where type II subtype of BZR, BZ2, is predominant), whereas these partial agonists potentiated the GABA response as much as diazepam in CPJ neurones (where the type I subtype of BZR, BZ1, is predominant). In CTX neurones where both type I and II variants are expressed, the augmentation ratio of the GABA response by diazepam was between the values in CPJ and SVH neurones. 4. In concentration-response relationships of BZR partial agonists, the threshold concentrations, KD values and maximal augmentation ratio of the GABA response were similar in all CTX, CPJ and SVH neurones. Also, in all preparations, the threshold concentration and KD values of diazepam action were 10 fold less than those induced by partial agonists. 5. All BZR agonists shifted the concentration-response relationship for GABA to the left without changing the maximum current amplitude, indicating that activation of both BZ1 and BZ2 increase the affinity of the GABAA receptor for GABA. 6. The results are important in clarifying the mechanism of anxiety and might explain the anxioselectivity of BZR partial agonists.

Aging↗
PubMed1993

Dietary fiber intake of Japanese younger generations and the recommended daily allowance.

A method was introduced for the estimation of total dietary fiber (TDF) intake of a population using a menu-oriented questionnaire and a menu-based calculation table. TDF intake correlated well with age in a population investigated, and in younger generations TDF consumption was very low (less than 11.5 g/day in teenagers). The similar results were obtained from the calculation using data of National Nutrition Survey (10.7 g/day). The foodstuffs they consumed were more processed and refined. This fact suggested that in younger generations a future resumption of their present eating habits might produce a serious lack of TDF intake in later years. To clarify the optimal level of TDF intake for the upper limit of recommended daily allowance (RDA) of an average Japanese, the following were measured and calculated. (I) Estimation of recent TDF intake (1990) and of 30 and 50 years ago (1955, 1935), based on TDF data of foodstuffs by the enzymatic-gravimetric method. (II) Measurement of the TDF of model duplicate meals and model composite diets for the average Japanese in 1985 using the same assay method. (III) Conversion of a recommendation of 20-35 g/day for American into RDA for Japanese considering energy consumption and lower fat intake. (IV) Re-estimation of the literature data on the adverse effects of DF on the human mineral balance considering the insufficient calcium intake of Japanese. The results indicated an RDA of 10-12 g TDF/1,000 kcal fit better for an average Japanese.

Adolescent↗
PubMed1993

Haemagglutinating activities of oral strains of Streptococcus milleri group.

Of a total 148 strains of Streptococcus milleri group, 66 agglutinated sheep erythrocytes. The haemagglutinating strains were confined to serotypes g, h, i, j or were untypeable, and had no Lancefield group antigens (A to G and K), all of which have been shown to belong to Streptococcus intermedius. Cell surface hydrophobicity did not significantly differ even between the agglutinating and non-agglutinating S. intermedius strains. The haemagglutinating activity of strain 0813-1 (serotype i) was partially sensitive to heat (100 degrees C, 30 min) or trypsin (1 mg/ml, 30 min) treatment, but completely lost after the heat and subsequent trypsin treatments. Only L-arginine, L-lysine (100 mM), mucin, and fetuin (1 mg/ml) partially inhibited the haemagglutination with native bacterial cells but completely inhibited that with heated cells, whereas none was inhibitory in the reaction with trypsin-treated cells. The results suggest that at least two haemagglutinins are involved in the agglutination of the S. intermedius strain and that the heat-stable but trypsin-sensitive haemagglutinin recognizes the receptors on the erythrocyte surface which contain L-arginine and L-lysine at the reactive site.

Amino Acids↗
PubMed1993

Enzymatic differentiation and biochemical and serological characteristics of the clinical isolates of Streptococcus angiosus, S. intermedius and S. constellatus.

Of the 29 'Streptococcus milleri' strains tested, all thirteen Streptococcus intermedius (DNA homology group 2) strains but none of the thirteen Streptococcus anginosus (group 1) strains produced beta-N-acetylglucosaminidase, beta-N-acetylgalactosaminidase, alpha-N-acetylneuraminidase, beta-galactosidase, alpha-glucosidase, and hyaluronidase. The three Streptococcus constellatus (group 3) strains produced only the latter two. Glycosidase production divided 274 clinical isolates into 103 S. anginosus, 101 S. intermedius, and 70 S. constellatus strains. Generally, strains of S. anginosus and S. intermedius were non-beta-haemolytic. API II and biotype Ia (lactose positive), but the former contained almost all API III strains and belonged to Lancefield group A/serotype a (A/a), -/b, C/c, -/d, -/e, F/f or G/k, and the latter included most of biotype IId (lactose negative) and serovar -/g, -/h, -/i or -/j. S constellatus strains were beta-, alpha- or gamma-haemolytic, of API I or II but mostly biotype Ib (lactose negative), and of F/- or -/b. S. intermedius was a major member of the oral isolates. Non-oral isolates were virtually all S. anginosus (mainly urogenital isolates) or S. constellatus (the other systemic isolates).

Adult↗
PubMed1993

Deoxyribonucleic acid relatedness and phenotypic characteristics of oral Streptococcus milleri strains.

Strains of oral Streptococcus milleri group were compared with the type strains of Streptococcus anginosus, S. intermedius, and S. constellatus by DNA-DNA hybridization at 60 degrees C. Of the 29 strains tested, twelve, twelve, and two strains were closely related to S. anginosus ATCC 33397T, S. intermedius ATCC 27335T, and S. constellatus ATCC 27823T, respectively. Generally, the strains classified in the S. anginosus group in DNA homology were non-beta-haemolytic and belonged to API S. milleri II and biotype I (lactose fermenting), whereas the strains of S. constellatus group were beta-haemolytic and belonged to API S. milleri I and biotype II (lactose non-fermenting). The strains of the S. intermedius group were all non-beta-haemolytic and belonged to API S. milleri II and mostly biotype II (lactose fermenting). Furthermore, all except one strain of the S. anginosus group were Lancefield group A/serotype a (A/a), ungroupable/serotype b (-/b), C/c, -/d, -/e, F/f or G/k, whereas those of the S. constellatus group were F/-. The strains of the S. intermedius group were -/g, -/h, -/i, -/j, or -/-.

DNA Probes↗
PubMed1992

Comparison of the vasodilator effects of thiopentone and pentobarbitone.

The aim of this study was to elucidate the vasodilator mechanisms of barbiturates. In helical strips of dog mesenteric artery, the effects of pretreatment with thiopentone and pentobarbitone on the contractions induced by KCl (2.0 x 10(-2) M) and norepinephrine (10(-5) M) in normal bathing fluid, and those induced by norepinephrine and caffeine (2.5 x 10(-2) M) in Ca(++)-free fluid were tested, and their effects on caffeine-induced contractions in skinned strips were also examined. Thiopentone, at concentrations over 10(-4) M, inhibited the KCl-induced contractions in normal bathing fluid and those induced by caffeine in Ca(++)-free fluid and, at concentrations over 3 x 10(-4) M, inhibited norepinephrine-induced contractions in normal and Ca(++)-free bathing fluids significantly. Pentobarbitone, at concentrations over 3 x 10(-4) M, inhibited KCl- and norepinephrine-induced contractions in normal bathing fluid significantly, whereas contractions in Ca(++)-free fluid induced by norepinephrine and caffeine were inhibited only by a high concentration (10(-3) M) of pentobarbitone. Caffeine-induced contractions of chemically skinned fibres were more susceptible to inhibition by thiopentone than by pentobarbitone. These results suggest that the vasodilator effect of thiopentone is mediated via its intracellular inhibitory effect and that, in contrast, the vasodilator effect of pentobarbitone can be attributed mainly to its Ca(++)-channel blocking action.

Animals↗
PubMed1992

Serological and biological characteristics of "Streptococcus milleri" isolates from systemic purulent infections.

Ninety-one Streptococcus milleri strains isolated from various systemic purulent lesions of 68 patients were examined by physiological and serological tests. Most strains formed a smooth colony (66 strains), did not form spontaneous aggregation of cells in BHI broth culture (79), were non-beta-haemolytic (alpha-35 or non-41), and belonged to biotype Ia (49) or Ib (34) and to API taxa S. milleri I (41) or II (38). Almost all of the beta-haemolytic strains as well as two-fifths of the non-beta-haemolytic belonged to API taxon I; strains of API taxa II and III were non-beta-haemolytic and non-haemolytic, respectively. Two-fifths (38) of the isolates belonged to one of eight serotypes, a-g and k, and more than half (47) to Lancefield groups A, C, F or G, the most frequent being type b (19) and group F (33). Fifteen strains carried simultaneously type a/group A, b/C, c/C, e/G, f/F or k/G antigens. Nineteen were neither typable nor groupable. All the 38 serotypable isolates were non-beta-haemolytic and not members of API taxon III, and were serologically and physiologically similar to oral S. milleri. The isolates from various infected sites--sputum, thorax, abdomen, urogenitalia, skin, eye and dental--exhibited distinct combinations of biological and serological properties. These results suggest that serotyping, haemolytic properties and API taxon, and their combinations, would be useful methods to trace oral S. milleri in systemic infections.

Abdomen↗
PubMed1992

Restricted distribution of Streptococcus milleri carbohydrate type antigens amongst other viridans streptococci.

The distribution of oral Streptococcus milleri carbohydrate type antigens in other viridans streptococcus species was examined. Rantz-Randall extracts of cells of the test strains grown in broth containing glucose were allowed to react with typing or grouping antisera for S. milleri serotypes a-k, or Lancefield groups A-G and K. Of 93 strains comprising more than 12 streptococcal species that included S. mutans and S. sanguis complexes, only 15 S. salivarius strains and one S. mitis strain were immunologically related to S. milleri serotype f. Unlike S. milleri strains, S. salivarius type f strains belonged to Lancefield group K, whereas the S. mitis strain was closely related to S. milleri serotype f but did not react with any of the Lancefield grouping antisera tested. Results suggest that oral S. milleri strains can be distinguished serologically from other oral viridans streptococci and that the typing antisera used in our researches might differentiate S. milleri isolates from the mouth from those associated with systemic purulent infections.

Antigens, Bacterial↗