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Biomedical subjects

T Shibata

Publications and source records attributed to T Shibata.

At least 361 records · Page 20Linked to original sources

[Complication of reservoir hepatic artery infusion chemotherapy and additional treatments].

In 54 patients who underwent hepatic artery infusion chemotherapy for hepatic tumors at our hospital between January 1990 and December 1996, we investigated the complications of this therapy and the therapeutic techniques following its discontinuation. The arterial infusion was discontinued in 36 of the 54 patients; 13 due to death (mean survival period: 15.7 months), and 23 in whom occlusion of the reservoir, etc. made it impossible to use arterial infusion (mean period of use: 13.8 months), and the minimum duration of use was 41 days and maximum duration of use 992 days. The most common complication of the reservoir hepatic artery infusion was reservoir occlusion (14.8%). Another serious complication was reservoir deviation outside the blood vessel in two patients; deviation in to the gastric lumen in one case and intraperitoneal deviation in the other. Four hepatocellular carcinoma patients, in whom it became impossible to use the reservoir due to its occlusion, underwent re-hepatectomy. Three of them survived for more than two years following supplemental local therapy, including subarterial injection, TAE, PEIT, microwave tumor coagulation (MTC). Of four patients with colon cancer metastasizing to the liver, one could undergo re-hepatectomy, one received subarterial injection, and two have survived without relapse. Two of three patients with breast cancer underwent systemic chemotherapy and endocrine therapy successfully, while the third one underwent subarterial injection and TAE, and is still under observation. Hepatic artery infusion should sometimes be discontinued owing to complications caused by various factors. Even if it becomes impossible to use the reservoir, local therapeutic techniques, including re-hepatectomy, TAE, PEIT, MTC, etc., may be performed in some patients. These findings suggest that it is necessary to review the interdisciplinary treatment so as to be appropriate to the primary disease.

Aged↗

[CT guided percutaneous microwave tumor coagulation therapy for local recurrence of rectal cancer].

PURPOSE: To evaluate the usefulness of the CT guided percutaneous microwave tumor coagulation (PMTC) therapy for local recurrence of rectal cancer. MATERIALS AND METHODS: The CT guided PMTC was performed for two patients with local recurrence of rectal cancer. Maximum axial diameter of the tumor was 30 mm on CT images. With patients in the prone position on the CT table, a 14-gauge needle-electrode was used to penetrate the tumor under epidural and local anesthesia. PMTC was performed with an output of 60 watts for 60 seconds at a time. Effects of the PMTC were evaluated by CT images obtained three months after the therapy. RESULTS: In both cases, there was no evidence of tumor growth on the CT images. Clinical symptoms disappeared soon after the therapy, and no major complication was observed. CONCLUSION: The CT guided PMTC therapy was useful for local recurrence of rectal cancer.

Aged↗

[Preoperative chemoradiation therapy for advanced rectal cancer].

Preoperative concurrent chemoradiation therapy with 5-fluorouracil and cisplatin was applied for advanced rectal cancer. Eligible criteria were as follows: no previous treatment, 4 more than hemicircular occupation, T3 or more invasion to adjacent organs or lymph node metastasis on CT scan, tumor fixation by digital examination. Eleven patients were enrolled with this regimen consisting of 5-FU; 500mg/day x5/w x4, CDDP; 10mg/day X 5/w x4 and radiation; 2Gy x 5/w x 4. As a toxicity, grade 2 leukopenia in 2 cases, grade 2 GI symptoms in one case and radiation dermatitis was observed in 8 cases. As a local response, there were PR in 10 cases and NC in 1 case. Surgical resection was performed on 8 patients. Histological responses in the resected specimens were grade 2, 5 cases; grade 1b, 1 case; and grade la, 2 cases. Operative radicalities were grade A, 3 cases; grade B, 3 cases; and grade C, 2 cases. Preoperative chemoradiation is one of the effective options in multimodal treatment for advanced rectal cancer.

Adenocarcinoma↗

[A case of isolated tricuspid valve endocarditis caused by Campylobacter fetus].

We reported a rare case of isolated tricuspid valve endocarditis in a non-addict with no underlying cardiac disease. A 48-year-old man was presented with high fever and newly developed leg edema. The diagnosis of tricuspid endocarditis was established following detection of a large vegetation (3.0 cm) on the tricuspid valve on echocardiography. One blood culture showed positive for Campylobacter fetus. At operation, a large and a small vegetation were found attached to the anterior leaflet of the tricuspid valve, and the septal leaflet was also found to be involved by the infective endocarditis. These leaflets were therefore removed and the tricuspid valve was replaced with CarboMedics valve. He has remained free of endocarditis for nineteen months after surgery.

Campylobacter Infections↗

Conformational distortion of sugar moieties in the RecA-bound DNA structure determined by a simulated annealing method.

We recently reported an NMR study indicating that the DNA structure bound to RecA protein contains a novel deoxyribose-base stacking interaction. Although the final structure calculated by the simulated annealing was well defined, the type of sugar puckers was neither pure C2'-endo nor C3'-endo, but something in between. This implies that the sugar moieties in the RecA-bound state actually take an intermediate puckering, but we can not exclude the possibility that RecA-bound DNA takes multiple conformations between the S-type and N-type of sugar puckers. In either case, the DNA structure within RecA filaments shows a unique property that is distinct from canonical DNA structures.

DNA↗

[Estimated production by the official inspection of coal-tar dyes (including dye aluminum lakes) in 1996].

The number of official inspection of coal-tar dyes and their lakes from April in 1996 till March in 1997 were 581 in total. The quantity which passed inspection amounted to 164.5 ton in Japan. The production of color in each month was summarised in Table1, and by each producing company in Table2. The food coal-tar dye produced in the largest quantity was Food Yellow No. 4, occupying 43.4% in this period.

Coal Tar↗

[Determination and survey of starting materials, intermediates, and subsidiary colors in food color of azo dye by high performance liquid chromatography].

A method for determination of starting materials, intermediates and subsidiary colors in food color of azo dye was developed by use of HPLC. The following conditions were used for analysis: column, L-column ODS (4.6 mm phi x 250 mmL); mobile phase, 0.02 M ammonium acetate (A), acetonitrile (B); concentration gradient, perform the linear concentration gradient from A:B (100:0) to (60:40) for 40 min; detection, starting materials and intermediates at 239 nm, and subsidiary colors at 510 nm. Standard material, domestic product and imported product were analyzed by the present HPLC method and impurities were measured. Recoveries of each impurity from azo dye averaged 99.1-103.5%. The detection limit was 0.05 microgram/g for each impurity.

Azo Compounds↗

A possible role of the C-terminal domain of the RecA protein. A gateway model for double-stranded DNA binding.

According to the crystal structure, the RecA protein has a domain near the C terminus consisting of amino acid residues 270-328 (from the N terminus). Our model building pointed out the possibility that this domain is a part of "gateway" through which double-stranded DNA finds a path for direct contact with single-stranded DNA within a presynaptic RecA filament in the search for homology. To test this possible function of the domain, we made mutant RecA proteins by site-directed single (or double, in one case) replacement of 2 conserved basic amino acid residues and 5 among 9 nonconserved basic amino acid residues in the domain. Replacement of either of the 2 conserved amino acid residues caused deficiencies in repair of UV-damaged DNA, an in vivo function of RecA protein, whereas the replacement of most (except one) of the tested nonconserved ones gave little or no effect. Purified mutant RecA proteins showed no (or only slight) deficiencies in the formation of presynaptic filaments as assessed by various assays. However, presynaptic filaments of both proteins that had replacement of a conserved amino acid residue had significant defects in binding to and pairing with duplex DNA (secondary binding). These results are consistent with our model that the conserved amino acid residues in the C-terminal domain have a direct role in double-stranded DNA binding and that they constitute a part of a gateway for homologous recognition.

Adenosine Triphosphate↗

Dominant negative inhibition of the association between beta-catenin and c-erbB-2 by N-terminally deleted beta-catenin suppresses the invasion and metastasis of cancer cells.

Aberrant tyrosine phosphorylation of beta-catenin inactivates the E-cadherin-mediated cell adhesion and invasion suppressor system in cancer cells. Elucidation of the association between beta-catenin and c-erbB-2 protein prompted us to investigate whether interference with this interaction can change the invasive phenotype. In a human gastric cancer cell line, TMK-1, N-terminally deleted beta-catenin, which binds to c-erbB-2 but not to cadherin, inhibited the association between endogenous beta-catenin and c-erbB-2 protein, and suppressed the tyrosine phosphorylation of beta-catenin. Cells expressing truncated beta-catenin exhibited markedly reduced invasiveness in vitro and peritoneal metastasis in vivo, and developed an epithelial morphology. These results suggest that tyrosine phosphorylation of beta-catenin regulated by c-erbB-2 protein may play an important role in the invasion, metastasis and morphogenesis of cancer cells and that inhibition of the aberrant tyrosine phosphorylation of beta-catenin effectively prevents invasion and metastasis of cancer cells.

Animals↗

EAAT4 is a post-synaptic glutamate transporter at Purkinje cell synapses.

To study cellular and subcellular localizations of the glutamate transporter EAAT4, antibody was raised against the N-terminal peptide. On immunoblotting the antibody recognized a band in membrane extracts from the cerebellum, but not from the forebrain. Immunohistochemistry revealed that its distribution was restricted to the cerebellar molecular layer, where the immunoreactivity was observed as numerous punctate stainings. Electron microscopy showed the antibody to label dendritic spines of the Purkinje cells. EAAT4 is, therefore, a Purkinje cell-specific, postsynaptic transporter. Together with dense localization of other transporter subtypes in Bergmann astrocytic membranes, Purkinje cell synapses are thus provided with distinct glutamate transporter subtypes at discrete synaptic elements, which would play important roles in regulating excitability of the Purkinje cells and protecting against excitotoxicity.

ATP-Binding Cassette Transporters↗

Recombinant human tumour necrosis factor-alpha suppresses synthesis, activity and secretion of lipoprotein lipase in cultures of a human osteosarcoma cell line.

The effect of recombinant human tumour necrosis factor-alpha (TNF-alpha) on synthesis, activity and secretion of lipoprotein lipase (LPL) was examined using a human osteosarcoma cell line, osteosarcoma Takase (OST). Treatment of OST cells with TNF-alpha decreased LPL synthesis, resulting in a decrease in expression of activity and secretion of LPL. When OST cells were incubated with glycerol tri[1-14C]palmitate, TNF-alpha decreased dose- and time-dependently the production of 14CO2 and the amounts of radioactivity incorporated into cellular triacylglycerol and phospholipid. The similar reduction of synthesis and activity of LPL as suppression of CO2 production and cellular lipid synthesis indicated that the suppression of 14CO2 production and 14C-labelled lipid synthesis was secondary. TNF-alpha also suppressed expression of proliferating cell nuclear antigen, indicating that it had an anti-proliferative activity on OST cells. The findings suggest that one cause of the anti-proliferative activity of TNF-alpha is the suppression of the LPL-mediated supply of non-esterified fatty acids as an energy source for growth.

Bone Neoplasms↗

Identification of protein synthesis elongation factor G as a 4.5 S RNA-binding protein in Escherichia coli.

Escherichia coli 4.5 S RNA is metabolically stable and abundant. It consists of 114 nucleotides, and it is structurally homologous to domain IV of mammalian signal recognition particle (SRP) RNA. In this study, we found two 4.5 S RNA-binding proteins in cell extracts by means of a gel mobility shift assay. One protein was identified as Ffh, which has been characterized as 4.5 S RNA-binding protein. The other protein was separated from Ffh by two consecutive column chromatographic elutions and by monitoring the 4.5 S RNA binding activity. After the second chromatography, a dominant protein with an approximate molecular weight of 78,000 was associated with 4.5 S RNA binding activity. A sequence of the NH2-terminal 19 residues of the 78-kDa protein was completely identical to that of the protein elongation factor G (EF-G) of E. coli, and further it cross-reacted with antiserum against E. coli EF-G. The results obtained using a synthetic oligo RNA corresponding to the 23 S rRNA defining the EF-G binding site indicated that 4.5 S RNA and 23 S rRNA are competitive in 4.5 S RNA binding and that a decanucleotide sequence conserved between them serves as a binding site for EF-G. Conservation of the SRP RNA binding activity of EF-G from Bacillus subtilis suggests that the binding of EF-G to SRP RNA is essential for its function.

Amino Acid Sequence↗

Role of neuronal nitric oxide in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced dopaminergic neurotoxicity.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) causes nigrostriatal dopaminergic pathway damage similar to that observed in Parkinson disease (PD). To study the role of NO radical in MPTP-induced neurotoxicity, we injected MPTP into mice in which nitric oxide synthase (NOS) was inhibited by 7-nitroindazole (7-NI) in a time- and dose-dependent fashion. 7-NI dramatically protected MPTP-injected mice against indices of severe injury to the nigrostriatal dopaminergic pathway, including reduction in striatal dopamine contents, decreases in numbers of nigral tyrosine hydroxylase-positive neurons, and numerous silver-stained degenerating nigral neurons. The resistance of 7-NI-injected mice to MPTP is not due to alterations in striatal pharmacokinetics or content of 1-methyl-4-phenylpyridinium ion (MPP+), the active metabolite of MPTP. To study specifically the role of neuronal NOS (nNOS), MPTP was administered to mutant mice lacking the nNOS gene. Mutant mice are significantly more resistant to MPTP-induced neurotoxicity compared with wild-type littermates. These results indicate that neuronally derived NO mediates, in part, MPTP-induced neurotoxicity. The similarity between the MPTP model and PD raises the possibility that NO may play a significant role in the etiology of PD.

3,4-Dihydroxyphenylacetic Acid↗

Helicobacter pylori infection in patients with gastric carcinoma in biopsy and surgical resection specimens.

BACKGROUND: The discrepancy between the high seropositivity for Helicobacter pylori (H. pylori) and the low diagnostic yield of H. pylori organism in gastric biopsies of patients with gastric carcinoma has yet to be clarified. The present study attempted to clarify this controversial point by performing a comparative evaluation between the detection rate of H. pylori in biopsy and in surgical specimens. METHODS: The presence of H. pylori in biopsy samples from 50 patients with gastric carcinoma and 50 age-matched controls was evaluated histologically. Six histologic sections were obtained from gastric noncancerous areas and the presence of H. pylori was evaluated in those H. pylori negative patients who underwent gastrectomy. RESULTS: H. pylori was positive in 35 of 50 controls (70%). In biopsy samples, H. pylori was detected in 29 of 37 patients (78.4%) with early gastric carcinoma, 7 of 13 (53.8%) with advanced carcinoma, 16 of 23 (69.6%) with intestinal type of gastric carcinoma, and 20 of 27 (74.1%) with diffuse type of carcinoma. Studies carried out in gastrectomy specimens increased the diagnostic yield of H. pylori to 33 (89.2%), 12 (92.3%), 19 (82.6%), and 26 (96.3%) in patients with early, advanced intestinal, and diffuse types of gastric carcinoma, respectively. Overall, H. pylori was positive in 36 biopsy specimens (72%) and 45 gastrectomy specimens (90%). Namely, the detection of H. pylori infection was significantly higher in patients with gastric carcinoma using gastrectomy specimens than in patients with gastric carcinoma using biopsy specimens only (P < 0.05). CONCLUSIONS: These results indicate that the actual prevalence of H. pylori in patients with gastric carcinoma is considerably higher than that previously reported.

Biopsy↗

Endo.SK1: an inducible site-specific endonuclease from yeast mitochondria.

Site-specific endonucleases have been found in various eukaryotic organelles such as mitochondria, chloroplasts and nuclei. These endonucleases initiate site-specific or homologous gene conversion in mitochondrial and nuclear DNA. Here, we report a new site-specific endonuclease activity, Endo.SK1, identified in mitochondria of strain SK1, a homothallic diploid strain of Saccharomyces cerevisiae. Nucleotide sequences around the Endo.SK1-cleavage sites are different from those of known yeast site-specific endonucleases. The Endo.SK1 activity is, at least partly, specified by a gene in the SK1-derived mitochondria. A novel feature of the Endo.SK1 activity is its inducibility: the endonuclease activity was induced by ca. 40-fold by transfer of cells from a glucose medium into an acetate medium, and was then repressed. This transient induction was independent of the ploidy level of the cells, and coincided with induction of fumarase, a mitochondrial enzyme involved in the TCA cycle. Co-induction and co-repression of the mitochondrial site-specific endonuclease activity and a respiration-related enzyme indicate that the endonuclease activity in regulated in response to physiological conditions, and suggest a possible role for the endonuclease in mitochondrial DNA metabolism.

Bacillus Phages↗

Reoxygenation after single irradiation in rodent tumors of different types and sizes.

PURPOSE: To investigate the variation of reoxygenation patterns after single irradiation in murine tumors of different types and sizes. METHODS AND MATERIALS: Whole-body single irradiation of 13 to 15 Gy was delivered to 10 mm RIF1 tumors of C3H/He mice, 22 mm SCCVII tumors of C3H/He mice, and 16 mm EMT6 tumors of Balb/c mice. Thereafter, changes in the hypoxic fraction with time were determined by the paired survival curve method. The data were compared with the results we had ++previously obtained with 10 mm SCCVII and 10 mm EMT6 tumors. RESULTS: The hypoxic fraction at 1 h after the priming irradiation was 26% for 10 mm RIF1 tumors, 48% for 10 mm SCCVII tumors, and 100% for 10 mm EMT6 tumors. Thus, RIF1 and SCCVII tumors, both of which have few necrotic areas, showed rapid reoxygenation, whereas EMT6 tumors, which have large necrotic areas, reoxygenated slowly. Although the hypoxic fraction returned to the pretreatment level within 72 h in 10 mm SCCVII and 10 mm EMT6 tumors, it did not in 10 mm RIF1 tumors. In contrast, the patterns of reoxygenation were similar between 22 mm and 10 mm SCCVII tumors and between 16 mm and 10 mm EMT6 tumors. CONCLUSION: The three tumors showed different patterns of reoxygenation. Tumors that have a low proportion of necrosis may reoxygenate rapidly. However, tumor size appeared to have less influence on the pattern of reoxygenation.

Animals↗

Dynamic changes in expression of glutamate transporter mRNAs in developing brain.

Developmental changes in gene expression for three glutamate transporter subtypes in the mouse brain were analysed by in situ hybridization. During embryonic stages, GluT-1 and GLT-1 mRNAs were expressed at high levels in the ventricular zone, whereas EAAC1 mRNA was not detected in the zone. In the mantle zone, transcription levels of three transporter mRNAs were low during embryonic stages, and these levels, especially those of the GluT-1 and GLT-1 mRNAs, displayed remarkable increases postnatally to reach maximal levels at 14 days of age. These dynamic developmental regulations suggest that the glutamate transporter not only regulates the excitatory synaptic transmission at mature stages, but might also be intimately involved in the brain development.

ATP-Binding Cassette Transporters↗