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T Ohshima

Publications and source records attributed to T Ohshima.

At least 127 records · Page 7Linked to original sources
PubMed1999

In vivo cisplatin resistance depending upon canalicular multispecific organic anion transporter (cMOAT).

The in vitro sensitivities to cisplatin of AH66 and AH66F cells, a variant obtained from AH66 cells, were very similar, when assayed in a medium containing 5% fetal bovine serum (FBS), whereas in the in vivo experiments AH66F cells were sensitive and AH66 cells were highly resistant to cisplatin. In this study, we examined the mechanism of the in vivo cisplatin resistance of AH66 cells. The in vitro cisplatin sensitivity of AH66 cells was lowered by changing FBS to 5% ascites fluid (ASF) in the assay medium and the sensitivity in FBS by treatment with buthioninesulfoximine (BSO). The sensitivity of AH66F cells was not changed by these treatments. Moreover, after culture in 5% ASF for 48 h, the accumulation of cisplatin in AH66 cells was decreased and the efflux of cisplatin from the cells was accelerated. The accumulation of cisplatin in AH66 cells in ASF was increased by pretreatment with BSO, sodium azide or probenecid. Then, we examined the expression of the glutathione (GSH) conjugate efflux pump family. Among them, only the expression of canalicular multispecific organic anion transporter (cMOAT) in AH66 cells was decreased by culture in FBS and enhanced by ASF. These results suggest that some substances contained in ASF enhanced the expression of cMOAT in the plasma membrane of AH66 cells and this transporter actively extruded cisplatin-GSH conjugate from the cells. Consequently, AH66 cells afford a cisplatin-resistant tumor in the host.

Animals↗
PubMed1999

Total synthesis and chemical biology of the sarcodictyins.

The sarcodictyins A-F and eleutherobin comprise a family of marine-derived diterpenoids with potent cytotoxicities against various tumor cell lines. Investigations have revealed that several of these compounds exert their cytotoxic effects through tubulin binding in a mechanism analogous to that of the clinical anticancer drug Taxol. The biological importance, challenging molecular architecture, and relative scarcity of these natural products have prompted several groups to undertake their total chemical synthesis. In this review, we summarize the current synthetic efforts and examine the preliminary structure-activity relationships which have emerged from early combinatorial libraries.

Animals↗
PubMed1999

Surgical management of symptomatic intrasellar arachnoid cysts--two case reports.

Two patients with symptomatic intrasellar arachnoid cyst were successfully treated. A 67-year-old female with a cyst 20 mm in diameter developed headache and visual disturbance. She was treated by transsphenoidal surgery. A 59-year-old male with a cyst measuring 35 x 30 x 50 mm causing headache, visual disturbance, and deterioration of consciousness was managed by wide resection of the cyst wall via craniotomy. Postoperative courses in both patients were uneventful. Transsphenoidal surgery may be suitable for small to medium-sized cysts, although tight packing of the sella is mandatory to prevent leakage of cerebrospinal fluid. However, craniotomy is recommended for large intra- and suprasellar arachnoid cysts to avoid this complication, and to achieve sufficient communication between the cyst and the subarachnoid cistern.

Adult↗
PubMed1999

Total Synthesis of Sanglifehrin A.

The immunosuppressive agent sanglifehrin A has been prepared for the first time by total synthesis. The construction of the macrocyclic unit of the target molecule was achieved through a selective intramolecular Stille coupling, and the spirolactam unit by Paterson-aldol reactions. The final steps involve an intermolecular Stille coupling and the opening of the internal acetal unit. This convergent synthesis opens the way for the synthesis of libraries of novel sanglifehrin analogues for biological screening.

Journal Article↗
PubMed1999

[Inhibitory effects of therapeutic reagents on the PCR detection of hepatitis C virus in serum and their elimination by RNA extraction methods].

Inhibitors of enzymatic amplification in serum may cause false-negative results for direct detection of hepatitis C virus (HCV) by polymerase chain reaction (PCR). This study was undertaken to demonstrate inhibitory effects of the therapeutic reagents on the PCR detection of HCV and to evaluate the efficacy of their elimination by RNA extraction methods. RNA was extracted using a manual method based on organic extraction and precipitation of RNA (SepaGene RV-R, Sanko Junyaku) or an automated system based on specific capture of HCV-RNA with probes and magnetic bead/fluid (B/F) separation (Roche Molecular Systems). When RNA was extracted by SepaGene RV-R from serum containing 10(5) copies per ml of HCV and amplified for HCV-RNA in the presence of hemoglobin, bilirubin, or heparin by Amplicor HCV (Roche Molecular Systems), results tended to be negative. In addition to these, two therapeutic reagents, ATP and dextran sulfate sodium were also found to have inhibitory effects. When ATP at concentrations up to 5 mM was added to the sera and RNA was extracted with SepaGene RV-R, there were no inhibitory effect on the detection of either HCV-RNA or the internal control. In contrast, when dextran sulfate sodium up to 1 mM was added to the sera, there was a dose dependent inhibitory effect on detection of both HCV-RNA and the internal control. When HCV-RNA was extracted by the automated system, the inhibitory effect of dextran sulfate sodium was successfully eliminated. In conclusion, dextran sulfate sodium and ATP were newly identified as inhibitors that may be present in serum, and the efficacy of eliminating these substances varied among RNA extraction methods.

Adenosine Triphosphate↗
PubMed1998

Cyclin-dependent kinase 5-deficient mice demonstrate novel developmental arrest in cerebral cortex.

The cerebral cortex of mice with a targeted disruption in the gene for cyclin-dependent kinase 5 (cdk5) is abnormal in its structure. Bromodeoxyuridine labeling reveals that the normal inside-out neurogenic gradient is inverted in the mutants; earlier born neurons are most often found superficial to those born later. Despite this, the early preplate layer separates correctly and neurons with a normal, pyramidal morphology can be found between true marginal zone and subplate. Consistent with their identity as layer VI corticothalamic neurons, they can be labeled by DiI injections into thalamus. The DiI injections also reveal that the trajectories of the cdk5(-/-) thalamocortical axons are oblique and cut across the entire cortical plate, instead of being oriented tangentially in the subcortical white matter. We propose a model in which the cdk5(-/-) defect blocks cortical development at a heretofore undescribed intermediate stage, after the splitting of the preplate, but before the migration of the full complement of cortical neurons.

Animals↗
PubMed1998

DNA sequence motifs are associated with aberrant homologous recombination in the mouse macrophage migration inhibitory factor (Mif) locus.

Homologous recombination is a precise genetic event that can introduce specific alteration in the genome. A planned targeted disruption by homologous recombination of the macrophage migration inhibitory factor (Mif) locus in mouse embryonic stem (ES) cells yielded the targeted clones, some of which had genomic rearrangements inconsistent with the expected homologous recombination event. A detailed characterization of the recombination breakpoints in two of these clones revealed several sequence motifs with possible roles in recombination. These motifs included short regions of sequence identity that may promote DNA alignment, multiple 5'-AAGG/TTCC-3' tetrameres, topoisomerase I consensus sites, and AT-rich sequences that can promote DNA cleavage and recombination. A retrovirus-like intracisternal-A particle (IAP) family sequence was also identified upstream of the Mif gene, and the LTR of this IAP was involved in one of the recombinations. Identification and characterization of such sequence motifs will be valuable for the gene targeting experiments.

Adenine Nucleotides↗
PubMed1998

RF system of the SPring-8 storage ring.

Construction of three RF stations in the storage ring of SPring-8 has been completed. The design concept concentrates on avoiding a coupled-bunch instability which limits the stored current or makes the synchrotron radiation beam unstable. The cavity is bell-shaped to reduce the coupling impedance of the higher-order modes. The cavity dimensions are trimmed systematically to distribute the higher-order mode frequencies. Each cavity has two movable tuners. The temperature of the cavity cooling water is controlled within 0.02 K and the water flow is kept constant. The construction and commissioning of the SPring-8 storage ring RF system is reported.

Journal Article↗
PubMed1998

Genomic organization, chromosomal mapping, and promoter analysis of the mouse dentin sialophosphoprotein (Dspp) gene, which codes for both dentin sialoprotein and dentin phosphoprotein.

Our laboratory has reported that two major noncollagenous dentin proteins, dentin sialoprotein and dentin phosphoprotein, are specific cleavage products of a larger precursor protein termed dentin sialophosphoprotein (MacDougall, M., Simmons, D., Luan, X., Nydegger, J., Feng, J. Q., and Gu, T. T. (1997) J. Biol. Chem. 272:835-842). To confirm our single gene hypothesis and initiate in vitro promoter studies, we have characterized the structural organization of the mouse dentin sialophosphoprotein gene. This gene has a transcription unit of approximately 9.4 kilobase pairs and is organized into 5 exons and 4 introns. Exon 1 contains a noncoding 5' sequence, and exon 2 contains the transcriptional start site, signal peptide, and first two amino acids of the NH2 terminus. Exons 3 and 4 contain coding information for 29 and 314 amino acids, respectively. The remainder of the coding information and the untranslated 3' region are contained in exon 5. Chromosomal mapping localized the gene to mouse chromosome 5q21 in close proximity to other dentin/bone matrix genes. Computer analysis of the promoter proximal 1.6-kilobase pair sequence revealed a number of potentially important cis-regulatory sequences; these include the recognition elements of AP-1, AP-2, Msx-1, serum response elements, SP-1, and TCF-1. In vitro studies showed that the DSPP promoter is active in an odontoblast cell line, MO6-G3, with basal activity mapped to -95 bp. Two potential enhancer and suppresser elements were identified in the regions between -1447 and -791 bp and -791 and -95 bp, respectively. The structural organization of the dentin sialophosphoprotein gene confirms our finding that both dentin sialoprotein and dentin phosphoprotein are encoded by a single gene with a continuous open reading frame.

Amino Acid Sequence↗
PubMed1998

Growth and morphology of anchorage-dependent animal cells in a liquid/liquid interface system.

In general, anchorage-dependent animal cells cultivated on a solid culture substrate, such as polystyrene, are collected by trypsin treatment. This treatment may have detrimental effects such as the proteolysis of the cell membrane proteins. To avoid these effects, cell cultivation using a liquid/liquid interface system has been investigated. In this cultivation method, the cells grow at the interface between a culture medium and a hydrophobic liquid. In this study, various fluorocarbons (FC-40, FC-70, KPF-91, KPF-102, and KPF-142) were used as substrates for the interface, and the cultivation of fibroblast cells (L-929; the mouse-derived cell line) at the interfaces was investigated. Early in the cultivation period, the growth of L-929 cells depended on the substrate type. Although cell cultivation at the interfaces was possible, it was slower than that at the polystyrene surface. Cell spreading at the interfaces was relatively small, which indicates that cell adhesion at the interfaces may be weak. In particular, the cells at the MEM/FC-70 interface anchored with one another and formed multicellular hemispherical aggregations shaped like spheroids. The difference in the adhesions to the interfaces appears to be dependent on the contaminants contained in the fluorocarbons because the physical properties of the fluorocarbon did not affect the cell growth and adhesion. Moreover, subcultivation from the interfaces to the same interface was possible without trypsin treatment. In this case, the delay of the growth at the interfaces did not occur because the cells were not affected by trypsin treatment.

Animals↗
PubMed1998

Antioxidizing potentials of BHA, BHT, TBHQ, tocopherol, and oxygen absorber incorporated in a Ghanaian fermented fish product.

Raw whole fishes (Horse mackerel, Trachurus japonicus) were degutted and separately treated with antioxidants BHA, BHT, TBHQ and tocopherol before fermentation, by completely immersing the samples in 0.1% antioxidant solutions. Fish samples were then salted, fermented and dried to mark the end of processing. A portion of the control samples were packed in an oxygen absorber during storage for 2 months at room temperature to study the effect of oxygen scavenging on lipid oxidation. The moisture content and total lipid decreased with processing and storage. An inductive effect of the fish oil was observed with 2-thiobarbituric acid values and the formation of lysophos-phatidylcholine (LPC) for TBHQ and BHA treated fish during the fermentation process. Free fatty acid formation was detected in all fish samples throughout processing and storage. For samples treated with tocopherol, only *-tocopherol was detected at the end of 2 months storage. Although TBHQ showed the best antioxidative effect during processing, it was the fastest synthetic antioxidant to be depleted. However, relatively high levels of BHA were present in the sample after 2 months storage. Red color patches, suspected to be antioxidant degradative products, were observed around the operculum of TBHQ treated samples after processing.

Absorption↗
PubMed1998

Time-dependent expression of interleukin-10 (IL-10) mRNA during the early phase of skin wound healing as a possible indicator of wound vitality.

This study was performed to clarify whether interleukin-10 messenger RNA (IL-10 mRNA) could be a possible indicator for the distinction between intravital wounds and postmortem damage. After incision, mice were sacrificed from 0 to 180 min. The initial amount of IL-10 mRNA in each skin specimen was evaluated using the reverse transcriptase-polymerase chain reaction (RT-PCR). After 15 min there was a rapid increase in IL-10 mRNA which peaked at 60 min. A significant increase in IL-10 mRNA occurred between 30 and 180 min. During the 5 day postmortem interval the increase in time-dependent IL-10 mRNA expression was maintained and no significant increase in IL-10 mRNA expression occurred in the postmortem control. The increased expression of IL-10 mRNA could be considered a vital reaction in skin specimens with postmortem change. This study demonstrated the possible use of mRNA analysis for forensic wound examination because mRNA was detectable by RT-PCR over a longer postmortem time course.

Animals↗
PubMed1998

Quantitative determination of butylated hydroxyanisole, butylated hydroxytoluene, and tert-butyl hydroquinone in oils, foods, and biological fluids by high-performance liquid chromatography with fluorometric detection.

Concentrations of synthetic antioxidants butylated hydroxyanisole, butylated hydroxytoluene, and tert-butyl hydroquinone were quantified using a high-performance liquid chromatograph with spectrofluorometric detector. The antioxidants were separated and eluted on a reversed-phase column by gradient of a mixture of H2O/acetonitrile/acetic acid (66.5: 28.5:5, by vol) and a mixture of acetonitrile/acetic acid (95:5, vol/vol). The eluants were monitored at emission and excitation wavelengths of 310 and 280 nm, respectively. Calibration curves obtained using peak areas against concentration showed high coefficients of multiple determination (R2 > 0.99) for all antioxidants. Known concentrations of added antioxidant standards were recoverable within 98-99% from oils and over 93% from mouse blood. This method requires minimum sample extraction and purification before analysis and provides a relatively high percentage recovery. The method has been applied successfully for the measurement of antioxidant concentrations in oils, dried foods, and biological fluids.

Antioxidants↗
PubMed1998

A long term follow-up of a randomized trial comparing interferon-alpha with busulfan for chronic myelogenous leukemia. The Kouseisho Leukemia Study Group.

To evaluate the long-term effectiveness of interferon-alpha (IFN-alpha) therapy in patients with chronic myelogenous leukemia (CML) in chronic phase, we examined the updated outcomes of 159 patients who had been enrolled between 1988 and 1991 into a randomized trial comparing IFN-alpha with busulfan. At a median follow-up of 73 months, the median survival was 71 months in the IFN-alpha group and 55 months in the busulfan group (P=0.0563), and the median time of remaining in chronic phase was 58 months in the IFN-alpha group and 39 months in the busulfan group (P=0.4676). Landmark analysis showed a significant advantage in survival (P=0.009) and duration of chronic phase (P=0.0001) in patients with any cytogenetic response among the IFN-alpha group. About half patients were discontinued IFN-alpha administration in spite of cytogenetic response in this study. It appears that continuation of IFN-alpha might possibly confer a survival advantage. Pretreatment factors associated with cytogenetic response included high hemoglobin level, low percentage of peripheral basophils and low leukocyte counts. Multivariate analysis identified lower percentage of bone marrow basophilia (P=0.007) for survival advantage. If a group with a very good prognosis is predicted by a new prognostic model, it might be an option to wait for bone marrow transplantation.

Adult↗
PubMed1998

Response-oriented individualized induction therapy with six drugs followed by four courses of intensive consolidation, 1 year maintenance and intensification therapy: the ALL90 study of the Japan Adult Leukemia Study Group.

Adult patients with acute lymphoblastic leukemia (ALL) were treated according to the ALL90 study, the second prospective study for ALL of the Japan Adult Leukemia Study Group (JALSG). Its characteristics included response-oriented individualized induction therapy with six drugs (doxorubicin, mitoxantrone, vincristine, prednisolone, [corrected] cyclophosphamide and L-asparaginase), and a prospective comparison between allogeneic bone marrow transplantation (allo-BMT) and chemotherapy alone in patients below 45 years of age. The protocol consisted of one or two courses of induction, four courses of consolidation, and three courses of intensification including 12 month maintenance and six times of central nervous system (CNS) prophylaxis. Of 180 evaluable patients (median age, 43), 125 (69%) achieved complete remission (CR). Predicted overall survival (OAS), event-free survival and disease-free survival (DFS) were 15, 10 and 14%, respectively at the median follow-up period of 62 months. No specific toxicities were observed. Leukocytes < 30,000/microliter, normal karyotype, and blasts < 10% in bone marrow at day 15 of induction therapy were significantly favorable prognostic factors for the achievement of CR, DFS and OAS by univariate analysis. Multivariate analysis showed leukocytes < 30,000/microliter and blasts < 10% on day 15 was a significant factor for the achievement of CR, DFS and OAS. Ph-chromosome was found in 28% (36/130) of patients examined and was one of the worst prognostic factors. All Ph positive patients were predicted to die within 600 days. Allo-BMT was not significantly superior to chemotherapy with respect to DFS (P = 0.226). The overall results were inferior to those of the former ALL87 protocol. As reasons, the older median age of 43 years old (vs. 38 years old) and lower dose intensity, especially of l-asparaginase, etc. were suggested. However, patients with good prognostic factors (leukocyte < 30,000/microliter and age < 30 years old) showed better survival than others (P < 0.0001), and the result was similar to that of older children, the high risk group of childhood ALL, suggesting that ALL could be a disease of single entity, showing higher resistance to chemotherapy as patients become older.

Adult↗
PubMed1998

Response-oriented individualized induction therapy followed by intensive consolidation and maintenance for adult patients with acute lymphoblastic leukemia: the ALL-87 study of the Japan Adult Leukemia Study Group (JALSG).

The Japan Adult Leukemia Study Group conducted the ALL-87 study to determine whether response-oriented induction therapy and intensive consolidation and maintenance/intensification therapies could increase complete remission (CR) rate and survival in adult acute lymphoblastic leukemia (ALL). Of 121 patients registered, 116 were evaluated. Patients' ages ranged from 15 to 72 years (median, 38 years). Induction therapy, which consisted of doxorubicin, vincristine, cyclophosphamide, L-asparaginase and prednisolone, was given in a response-oriented individualized fashion. Patients were randomly allocated either to receive or not, intrathecal chemotherapy on day 8 of the induction therapy. Complete remission (CR) was obtained in 97 (83.6%) patients (90.2%) in patients of less than 50 years of age and 67.6% in patients 50 years of age or older). At a median follow-up period of 65 months, the predicted 6-year overall survival and event free survival (EFS) rates of 116 patients were 23.4 and 20.0%, respectively. Predicted 6-year survival and disease-free survival (DFS) rates of 97 CR patients were 28.2 and 24.5%, respectively. By multivariate analysis, patients under 40 years of age (P = 0.002) or those with a platelet count of more than 100,000/microliters (P = 0.004) were significant favorable prognostic factors for obtaining CR, and days to CR less than 50 (P = 0.003), patients under 50 years of age (P = 0.005) were significant favorable factors for longer DFS. There was no significant difference in CR rates and DFS between the two randomized groups according to the intrathecal chemotherapy on day 8. Response-oriented induction therapy produced a high CR rate, but fairly intensive consolidation and maintenance/intensification chemotherapies resulted in only a marginal effect on DFS in adult ALL. Although age is one of the most important prognostic factors in ALL, the outcome was unsatisfactory even in younger adult patients using chemotherapeutic regimen employed in this study.

Adolescent↗
PubMed1998

Forensic pathological observations on fatal injuries to the brain stem and/or upper cervical spinal cord in traffic accidents.

A retrospective study was performed on 149 forensic autopsy cases (12 in Kanazawa and 137 in Munich) of brain stem and/or upper cervical spinal cord (UCSC) injuries as a result of traffic accidents. Pedestrians were the most common type of victims, followed by car drivers. Eleven of the 12 Kanazawa victims were pedestrians. The total ratio of pedestrian victims gradually increased with age. The ponto-medullary junction was the most frequently injured site. A total of 146 cases demonstrated basal skull fractures and/or dislocation of the upper cervical joints: atlanto-occipital joint, atlanto-axial joint, or the joint between the 2nd and 3rd cervical vertebrae. However, in three cases, hyperextension of the neck unexpectedly caused brain stem injury neither associated with basal skull fracture nor with cervical dislocation. Intraventricular haemorrhage was found in 96 cases, suggesting a common feature associated with brain stem and/or UCSC injury. A tear of the basilar artery and that of the carotid artery was found in 17 and 20 cases respectively. A total of 39 victims demonstrated a blood alcohol concentration of over 0.5 mg/ml, and hyperextension of the neck occurred more frequently in these cases. In spite of the marked predominance of immediate death (138 cases), 11 cases (nine of brain stem injury and two of UCSC injury) had unexpected survival times of from 45 min to 12 h.

Journal Article↗