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K Takai

Publications and source records attributed to K Takai.

At least 109 records · Page 6Linked to original sources
PubMed1998

Acquired thermotolerance and temperature-induced protein accumulation in the extremely thermophilic bacterium Rhodothermus obamensis.

Temperature-induced changes in thermotolerance and protein composition were examined in heat-shocked cells and high-temperature-grown cells of the extremely thermophilic bacterium Rhodothermus obamensis. The survival at temperatures superoptimal for growth (90 and 95 degrees C) was enhanced in both heat-shocked cells and high-temperature-grown cells relative to that of cells grown at optimal temperatures. In a comparison of protein composition using two-dimensional gel electrophoresis, putative heat shock proteins (HSPs) and high-temperature growth-specific proteins (HGPs) were detected. N-terminal amino acid sequence analysis revealed that the putative HSPs were quite similar to the ATP-binding subunits of ABC transporters and the HGPs were proteins corresponding to domains II and III of elongation factor Tu. These results suggested that this extreme thermophile has developed temperature-induced responses that include increased survival under hyperthermal conditions, changes in protein composition, and also the production of novel HSPs.

Amino Acid Sequence↗
PubMed1998

Specific inhibition of influenza virus RNA polymerase and nucleoprotein gene expression by liposomally encapsulated antisense phosphorothioate oligonucleotides in MDCK cells.

We have demonstrated that antisense phosphorothioate oligonucleotides (S-ODNs) inhibit influenza A virus replication in MDCK cells. Liposomally encapsulated and free antisense S-ODNs with four target sites (PB1, PB2, PA and NP genes) were tested for their abilities to inhibit virus-induced cytopathogenic effects in a MTT assay using MDCK cells. The liposomally encapsulated S-ODN complementary to the site around the PB2 AUG initiation codon showed highly inhibitory effects. In contrast, the inhibitory effect of the liposomally encapsulated S-ODN targeted to PB1 was considerably decreased in comparison with that directed to the PB2 target site. The liposomally encapsulated antisense S-ODNs exhibited higher inhibitory activities than the free oligonucleotides, and showed sequence-specific inhibition, whereas free antisense S-ODNs were observed to inhibit viral adsorption to MDCK cells. Liposomal preparations of oligonucleotides facilitated their release from endocytic vesicles, and thus cytoplasmic and nuclear localization was observed. The activities of the antisense S-ODNs were effectively enhanced by using the liposomal carrier. Interestingly, the liposomally encapsulated FITC-S-ODN-PB2-as accumulated in the nuclear region of MDCK cells. However, weak fluorescence was observed within the endosomes and the cytoplasm of MDCK cells treated with the free antisense S-ODNs. The cationic lipid particles may thus be a potentially useful delivery vehicle for oligonucleotide-based therapeutics and transgenes, appropriate for use in vitro or in vivo.

Antiviral Agents↗
PubMed1998

Cognitive strategies and recall of pace by long-distance runners.

The purpose of this study was to examine whether long-distance runners with high or low performance of recalling running pace differed in their use of cognitive strategies in a race. Recalling pace means the accuracy which runners have to approach their self-set target pace in a race. 60 male competitive runners who participated in a 20-km intercollegiate race were categorized as either runners with high recall of pace (accurate) or the runners with low recall of pace (inaccurate) on the basis of the discrepancy between a self-set target time and actual time. Analysis showed that the 30 accurate recallers used the attention strategies more frequently for recalling running pace, used the strategy of following other runners less frequently, and set a more appropriate finish time in accordance with their running ability than the 30 inaccurate recallers. The accurate recallers, who monitored their running pace and fatigue by using attention strategies, would reproduce more accurate self-set target times in accordance with their running ability.

Adult↗
PubMed1998

Urinary tract infections following renal transplantation.

The incidence of urinary tract infections (UTIs) in 363 adult renal transplant recipients transplanted during the period 1990-96 has been analysed. UTI occurred in 96 patients (26%), most frequently during the first year after transplantation. Female recipients had significantly more UTI than male recipients (49% vs. 14%, p < 0.0001). There was no difference in the incidence of UTI between recipients receiving pig-tail catheters as ureteral stents or not, the figures being 21% vs. 28%, respectively. Age had no influence on the incidence of UTI. In 341 patients treated with cyclosporine the incidence of UTI was 28%, while in 15 patients treated with FK-506 only 1 patient (7%) had a UTI (ns). The majority of organisms cultured were gram-negative (76%), with approximately 1/3 being Escherichia coli and 1/5 being Enterococcus and Klebsiella/Enterobacter. The bacterial spectrum was not influenced by the recipient's age. UTI had no effect on the number of rejections, or on graft and patient survival in living donor transplant recipients. No significant difference was found in graft and patient survival rates at 3 yr between patients who had UTI or no UTI.

Adolescent↗
PubMed1998

[Urolithiasis associated with Crohn's disease: a case report].

We report a case of urolithiasis caused by surgical treatment for Crohn's disease. A 28-year-old woman was referred to our department for further examination of renal stones from the medical department in September, 1995. She suffered from Crohn's disease and had a history of jejuno-ileal resection because of perforation of the ileum in 1988. Radiographs revealed multiple bilateral renal stones, and the urine oxalate concentration was elevated. She was treated with extracorporeal shock wave lithotripsy and the administration of sodium bicarbonate and citrate, but these treatments did not prevent recurrence and enlargement of stones. Renal function was gradually worsened and we performed transurethral lithotomy and percutaneous nephrolithotripsy. The stones were mainly composed of oxalate calcium monohydrate. A renal biopsy was performed at the operation, showing deposition of crystals in almost all renal tubules. Diet therapy (low oxalate and low fat) and the administration of sodium bicarbonate and citrate were performed strictly and recurrence was not recognized 10 months after complete removal of the stones.

Adult↗
PubMed1997

Cleavage effect of oligoribonucleotides substituted at the cleavage sites with modified pyrimidine- and purine-nucleosides.

The precursor of an RNA molecule from T4-infected E. coli cells (p2Spl RNA) has the capacity to cleave itself at specific positions [UpA (139-140) and CpA (170-171)], within a putative loop and stem structure. This sequence-specific cleavage requires at least a monovalent cation and non-ionic detergents. In order to determine the influence of the pyrimidine and purine bases on these sequence-specific cleavage reactions, we studied the cleavage reactions of hairpin loop RNAs substituted at the cleavage sites with modified pyrimidine- and purine-nucleosides. The cleavage was affected by the 2'-hydroxyl groups and the bases of the pyrimidines, and the 6-amino group of the purine.

Base Composition↗
PubMed1997

Cytokine production regulating Th1 and Th2 cytokines in hemophagocytic lymphohistiocytosis.

Hemophagocytic lymphohistiocytosis (HLH) is caused by the hyperactivation of T cells and macrophages. The clinical characteristics associated with this disease result from overproduction of Th1 cytokines including interferon-gamma (IFN-gamma), interleukin-2 (IL-2), and tumor necrosis factor-alpha (TNF-alpha). In this study, we analyzed the production of IL-12 and IL-4, which determine Th1 and Th2 response, respectively, and IL-10, which antagonizes Th1 cytokines, in 11 patients with HLH. IL-12 was detected in plasma in all patients (mean peak value, 30.0 +/- 5.0 pg/mL), while IFN-gamma was massively produced in nine patients (mean peak value, 79.2 +/- 112.0 U/mL). IL-4 was not detected in any of the patients. Plasma IL-10 levels were elevated in all patients (mean peak value, 2,698.0 +/- 3,535.0 pg/mL). There was a positive correlation between the levels of IFN-gamma and IL-10 (P < .01). The plasma concentrations of these cytokines were initially high, before decreasing after the acute phase. However, the decrease in IL-10 levels was slower than that of IFN-gamma. Although the concentration of IL-12 was high at the acute phase, in some patients, a peak in the level was delayed until the chronic phase. Thus, in HLH, production of cytokines that promote development of Th1 cells appears to be predominant over that for Th2 cell development. Overproduction of IL-10 was also observed indicating that a mechanism suppressing hyperactivation of Th1 cells and monocytes/macrophages functions in patients with this disease.

Child↗
PubMed1997

Inhibition of HIV-1 replication by triple-helix-forming phosphorothioate oligonucleotides targeted to the polypurine tract.

We show the effects of triple-helix formation by assays of primer extension inhibition in vitro using two systems (two-strand-system (FTFOs) or three-strand-system (TFOs) targeted to the polypurine tract (PPT) of HIV-1. The FTFOs were more effective than the TFOs. We found that the FTFOs containing phosphorothioate groups at the 3'- and 5'-ends, or inside the hairpin loop, exhibited higher inhibitory effects on cDNA synthesis and greater exonuclease resistance than the unmodified FTFOs and TFOs. The abilities of the FTFOs containing phosphorothioate groups at the antisense sequence sites to inhibit HIV-1 replications were examined. The FTFOs containing phosphorothioate groups at the antisense sequence sites inhibit the replication of HIV-1 more efficiently than the antisense oligonucleotides, indicating sequence-specific inhibition of HIV-1 replication.

Anti-HIV Agents↗
PubMed1997

Specific inhibition of influenza virus RNA polymerase and nucleoprotein genes expression by liposomally endocapsulated antisense phosphorothioate oligonucleotides: penetration and localization of oligonucleotides in clone 76 cells.

Liposomally encapsulated phosphorothioate oligonucleotides with four target sites (PB1, PB2, PA, and NP) were synthesized and tested for inhibitory effects by a CAT-ELISA assay using the clone 76 cell line. The liposomally encapsulated phosphorothioate oligonucleotides (S-ODNs) complementary to the sites of the PB2-AUG and PA-AUG initiation codons showed highly inhibitory effects. Displacement of the target AUG initiation codon sequence to the 3'-end, 5'-end, and/or center sites on the antisense phosphorothioate oligonucleotides was studied with regard to the inhibition of influenza virus RNA polymerases and NP. The antisense phosphorothioate oligonucleotide containing the AUG initiation codon at the center site of the oligonucleotide had the highest inhibitory effects. The liposomally encapsulated phosphorothioate oligonucleotides exhibited higher inhibitory activity than the free oligonucleotides. Observation of clone 76 cells treated with the endocapsulated antisense phosphodiester oligonucleotide, FITC-ODNs-PB2-T3, by a confocal laser scanning microscope, revealed diffuse fluorescence, apparently within the cytoplasm. Interestingly, the endocapsulated antisense phosphorothioate oligonucleotide, FITC-S-ODNs-PB2-T3 accumulated in the nuclear region of clone 76 cells. However, weak fluorescence was observed in the endosomes and in the cytoplasms of the clone 76 cells treated with the free antisense phosphorothioate oligonucleotides.

Animals↗
PubMed1997

Hepatocyte growth factor is constitutively produced by human bone marrow stromal cells and indirectly promotes hematopoiesis.

Bone marrow (BM) stromal cells are required for normal hematopoiesis. A number of soluble factors secreted by these cells that mediate hematopoiesis have been characterized. However, the mechanism of hematopoiesis cannot be explained solely by these known factors, and the existence of other, still unknown stromal factors has been postulated. We showed that hepatocyte growth factor (HGF) is one such cytokine produced by human BM stromal cells. BM stromal cells were shown to constitutively produce HGF and also to express the c-MET/HGF receptor. The production of HGF was enhanced by addition of heparin and phorbol ester. Dexamethasone and tumor growth factor-beta (TGF-beta) inhibited the production of HGF. Interleukin-1 alpha (IL-1 alpha) tumor necrosis factor-alpha (TNF-alpha), and N6,2'-o-dibutyryl-adenosine-3':5'-cyclic monophosphate (dbc-AMP) showed no obvious influence on HGF production. Western blot analysis of HGF derived from BM stromal cells showed two bands at 85 and 28 kD corresponding to native and variant HGF, respectively. Addition of recombinant HGF significantly promoted the formation of burst-forming unit-erythroid (BFU-E) and colony-forming unit-granulocyte erythroid macrophage (CFU-GEM) by BM mononuclear cells in the presence of erythropoietin and granulocyte-macrophage colony-stimulating factor (GM-CSF), but the formation of CFU-GM was not modified. However, HGF had no effects on colony formation by purified CD34+ cells. Within BM mononuclear cells, c-MET was expressed on a proportion of cells (CD34-, CD33+, CD13+, CD14+, and CD15+), but was not found on CD34+ cells. We conclude that HGF is constitutively produced by BM stromal cells and that it enhances hematopoiesis. In addition, expression of c-MET on the stromal cells suggests the presence of an autocrine mechanism, operating through HGF, among stromal cells.

Bone Marrow↗
PubMed1997

Extremely thermostable phosphoenolpyruvate carboxylase from an extreme thermophile, Rhodothermus obamensis.

Phosphoenolpyruvate carboxylase (PEPC) was purified from an extremely thermophilic bacterium, Rhodothermus obamensis, growing optimally at 80 degrees C, which had recently been isolated from a shallow marine hydrothermal vent in Japan. The native enzyme was a homotetramer of 400 kDa in molecular mass, as estimated by gel filtration chromatography, and the subunit exhibited an apparent molecular mass of 100 kDa on sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The optimum temperature for enzyme activity was 75 degrees C. The enzyme exhibited an absolute requirement for divalent cations and a pH optimum of 8.0. The enzyme was extremely thermostable and there was no loss of enzyme activity on incubation for 2 h at 85 degrees C. The enzyme exhibited a positive allosteric property with acetyl-CoA and fructose 1,6-bisphosphate, and a negative one with L-aspartate and L-malate. These effectors affected not only the thermophilicity but also the thermostability of the enzyme, and the substrate, co-factors, and salts increased the thermostability as well. The extrinsic thermostabilization might be a possible mechanism for adaptation of the enzyme to high temperature.

Acetyl Coenzyme A↗
PubMed1997

Endoscopic sphincterotomy assisted by percutaneous transhepatic choledochal tube: a preliminary report.

We report a method of endoscopic retrograde sphincterotomy in patients in whom the optimal viewing of the papilla of Vater is hardly obtained. Percutaneous transhepatic cholangiodrainage (PTCD)-tube is placed under ultrasonographic guidance. PTCD-tube coming out of the papilla of Vater is observed by the endoscope and the guide wire inside the shpincterotome is inserted into the PTCD-tube. Sphincterotome is advanced into the common bile duct by the guidance of the guide wire and PTCD-tube. Sphincterotomy is performed in a usual fashion. Two patients with previous history of gastrectomy underwent this procedure with successful results. This method should be tried when usual method of EST is difficult and unsuccessful.

Aged↗
PubMed1997

Effects on archery performance of manipulating metamotivational state and felt arousal.

This study investigated the effect of the four different combinations of metamotivational state and felt arousal level (telic-low, paratelic-low, telic-high, paratelic-high) on archery performance. Skilled, average, and novice archers (n = 28) were voluntary subjects, randomly divided into 2 groups, balanced for ability. Each group performed 2 out of the 4 experimental conditions. In this reversal theory-based field experiment, telic and paratelic metamotivational states and arousal level were manipulated prior to archery performance. The hypothesis that archery performance would be superior under telic-low arousal conditions was rejected, but evidence pointed to the possible importance of hedonic tone in performance. Post boc analysis showed differences between combined high (telic-low, paratelic-high) and combined low (telic-low, paratelic-high) hedonic-tone groups which fell short of significance. This observation is taken as justification for further exploration of the relationship between hedonic tone and sports performance.

Adolescent↗
PubMed1997

[Retrograde radical cystectomy. Advantages of our "vesico-rectal tunnel" method].

BACKGROUND: The facilitation of dissecting the vesical pedicles and undisturbed preservation of the membranous urethra were investigated during radical cystectomy using the retrograde technique. METHODS: First, just as with radical prostatectomy, the prostate and the rectum were separated by blunt digital dissection. After the deep dorsal vein complex and the urethra were cut, the bladder and the rectum were also separated in a retrograde manner towards the Denonvillier's fascia. Then the peritoneum was opened and its lowest part was incised above the cul-de-sac. A tunnel was made beginning at the cut-end of the urethra to the cul-de-sac. Consequently, the bladder was lifted up by hand inserted this "vesico-rectal tunnel" and the bilateral remaining lateral pedicles were ligated and transsected without difficulty. RESULTS: Fourteen patients underwent radical cystectomy using this technique. Among them, the average operating time and blood loss in 4 patients received retrograde radical cystectomy accompanied with ileal conduit were 5 hours 15 minutes and 1606 ml, respectively. These in 9 patients received retrograde radical cystectomy followed by bowel orthotopic urinary reservoir were 7 hours and 6 minutes and 1086 ml, respectively. Another patient received ureterocutaneoustomy. CONCLUSION: Creating a "vesico-rectal tunnel" during radical cystectomy primarily by the retrograde extraperitoneal technique can afford to preserve the urethral sphincter and to ligate the pedicles easily. This method is fundamentally familiar to us because retrograde radical prostatectomy is now widely adopted and it may help to reduce the operating time even when there is a shortage of manpower.

Aged↗
PubMed1997

[Study of disposition of adriamycin and mitomycin C in liver by determination of plasma concentrations in hepatic vein and artery during intravenous constant infusion in rats].

The hepatic extraction ratios (EH) of adriamycin (ADR) and mitomycin C (MMC), which were administered clinically by an intra-hepatic arterial route, were measured in rats to clarify the disposition of ADR and MMC in liver. EH values of ADR and MMC were determined by comparing the femoral arterial and hepatic venous plasma concentrations at steady state during continuous intravenous administration. The EH value of ADR in rats at each infusion rate of 2, 10 and 50 micrograms/kg/min, was 0.290, 0.286 and 0.251, respectively. There was no significant difference between the EH values (p > 0.05). The systemic clearance (CLtot) at each infusion rate was 108, 77.6 and 72.9 ml/min/kg, respectively. The EH value of MMC in rats at each infusion rate of 2.5, 7.5 and 25 micrograms/kg/min, was 0.332, 0.358 and 0.360, respectively. There was no significant difference between the EH values, the same as for ADR. The systemic clearance (CLtot) at each infusion rate was 38.3, 36.1 and 35.3 ml/min/kg.

Animals↗
PubMed1997

[Antisense nucleic acid therapy of influenza virus].

We have demonstrated that Antisense phosphodiester (ODNs) and phosphorothioate oligonucleotides (S-ODNs) inhibit CAT (chloramphenicol acetyltransferase) protein expression in the clone 76 cell line, which is a derivative of the murine C127 cell line. This cell line expresses the influenza virus RNA polymerase and nucleoprotein (NP) genes in response to treatment with dexamethasone. Phosphodiester, phosphorothioate, and liposomally encapsulated oligonucleotides with four target sites (PB1, PB2, PA, and NP) were synthesized and tested for inhibitory effects by a CAT-ELISA assay using the clone 76 cell line. The liposomally encapsulated ODNs and S-ODNs complementary to the sites of the PB2-AUG and PA-AUG initiation codons showed highly inhibitory effects. On the other hand, the inhibitory effect of the S-ODNs targeted to PB1 was considerably decreased in comparison with the other three target sites. Liposome encapsulation afforded oligomer protection in serum-containing medium and substantially improved cellular accumulation. The liposomally encapsulated oligonucleotides exhibited higher inhibitory activity than the free oligonucleotides. Liposomal preparations of oligonucleotides facilitate release from endocytic vesicles, and thus, cytoplasmic and nuclear localization are observed following cell treatment. The activities of the unmodified oligonucleotides are effectively enhanced by using the liposomal carrier. In the observation of the endocapsulated antisense phosphodiester oligonucleotide, FITC-ODN-PB2-as treated clone 76 cells by a confocal laser scanning microscope, diffuse fluorescence was apparently observed in the cytoplasm. Interestingly, the endocapsulated antisense phosphorothioate oligonucleotide, FITC-S-ODN-PB2-as accumulated in the nuclear region of clone 76 cells. However, weak fluorescence was observed on the endosomes and in the cytoplasmes of the free antisense phosphorothioate oligonucleotides treated clone 76 cells.

DNA, Antisense↗
PubMed1997

[Diffuse large B-cell lymphoma mainly involving the heart and showing t(8;14) (q24;q32) with c-myc rearrangement].

A 77-year-old man was admitted because of massive pericardial effusion and cardiac tumor. Cytological examination of the effusion and histological examination of a subcutaneous tumor in the chest wall revealed diffuse large B cell lymphoma. The immunophenotype of tumor cells was CD5+ CD20+ CD22+ CD38+ HLA-DR+ CD19-. Chromosome analysis revealed complex abnormal karyotypes containing t(8;14) (q24;q32). C-myc gene rearrangement was shown by Southern blotting. Chemotherapy with pirarubicin, cyclophosphamide, vincristin, and prednisolone (THP-COP) was not effective for his lymphoma. He suffered from cardiac tamponade and died at 5 months after diagnosis. Autopsy revealed a large cardiac tumor, extensive epicardial infiltration, tiny tumors in the lung and pancreas, but no lymphadenopathy, the combination of which suggested a primary cardiac lymphoma. Immunohistochemistry for p53 protein showed nuclear staining of more than 50% of the lymphoma cells. In situ hybridization for EBER-1 was negative. Rearrangement of c-myc gene and overexpression of p53 protein are usually observed in Burkitt's lymphoma and some cases of high grade lymphomas including AIDS-associated non-Hodgkin lymphomas. In this case the association of these molecular findings and resistance to chemotherapy is suggested.

Aged↗