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Biomedical subjects

K Taguchi

Publications and source records attributed to K Taguchi.

At least 37 records · Page 2Linked to original sources
PubMed2001

Immunohistochemical detection of verotoxin receptors in nervous system.

Verotoxin receptor is a globotriaosylceramide (Gb3) present on vascular endothelial cells, in which the toxin causes hemolytic uremic syndrome. We established a sensitive method of immunohistochemical staining in serial sections using monoclonal antibodies (mAbs) against verotoxin and glycolipids that includes Gb3 and galactosylGb3 (GalGb3). With it, we showed co-localization of the verotoxin receptor and Gb3 in dorsal root ganglia (DRG) of humans, rabbits, rats and mice. We also used a very simple method to identify the presence of lipofuscin-like autofluorescence which complicates fluorescence microscopy observation of aged human nervous tissues.

Animals↗
PubMed2001

Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyalkanoates) copolymer from sugars by recombinant Ralstonia eutropha harboring the phaC1Ps and the phaGPs genes of Pseudomonas sp. 61-3.

Heterologous expression of the phaGPs and the phaClPs genes encoding 3-hydroxyacyl acyl carrier protein-coenzyme A transacylase and polyhydroxyalkanoate (PHA) synthase from Pseudomonas sp. 61-3, respectively, was performed in the phbCRe negative mutant, Ralstonia eutropha PHB-4. The recombinant strain of the R. eutropha PHB-4 produced PHA copolymers consisting of 3-hydroxybutyrate (3HB) and medium-chain-length 3-hydroxyalkanoate (mcl-3HA) units of 6-12 carbon atoms from sugars. The 3HB fraction in copolymers was very high (95-97 mol%). The PHA content in the recombinant strain could further be increased by the additional introduction of the phbABRe genes from R. eutropha encoding beta-ketothiolase and NADPH-depedent acetoacetyl-coenzyme A reductase. Differential scanning calorimetry analysis of the PHA copolymers produced by the recombinant R. eutropha PHB-4 have indicated that the PHA is a random copolymer of 3HB and mcl-3HA units.

Acyltransferases↗
PubMed2001

Altered expression of beta-catenin without genetic mutation in intrahepatic cholangiocarcinoma.

beta-catenin which has a role in E-cadherin mediated cell-to-cell adhesion, and is also involved in Wnt signaling pathways as a downstream signaling molecule accumulating in the cytoplasm and nucleus constitutively activates Tcf/LEF-associated transcription of oncogenic genes. We examined the expression pattern and the genetic alteration of beta-catenin to determine the role of beta-catenin in cancer formation and/or progression in intrahepatic cholangiocarcinoma (ICC). beta-catenin expression was immunohistochemically examined in 71 surgically resected ICC samples, and correlation between the expression pattern and clinicopathologic factors was investigated. Mutation analysis of beta-catenin exon 3, which included the responsible element for Wnt signaling was done in 55 samples, using PCR-SSCP and direct sequence methods. Immunohistochemical analysis revealed the reduced membranous expression of beta-catenin in 58 (82%) ICCs and aberrant nuclear expression in 11 (15%) ICCs. The membranous expression was preserved in 62% of the papillary adenocarcinomas, and was frequently reduced in tumors with a poorer histological differentiation (84%), with a significant difference (P =.01). Genetic analysis showed that none of the 55 ICCs examined carried mutations in beta-catenin exon 3. The present study indicates that reduced membranous expression of beta-catenin is associated with non-papillary ICCs which have a more malignant behavior, and that nuclear translocation of beta-catenin results in oncogenic events. Mutations in beta-catenin exon 3 do not appear to be responsible for nuclear translocation of beta-catenin in ICCs.

Aged↗
PubMed2001

Metastasis of renal cell carcinoma to central nervous system hemangioblastoma in two patients with von Hippel-Lindau disease.

Here we report tumor-to-tumor metastases identified in two patients with von Hippel-Lindau (VHL) disease. The first patient had bilateral renal carcinomas and multiple cerebellar hemangioblastomas, and the second patient had a renal carcinoma and multiple hemangioblastomas in the retina, cerebellum and spinal cord. A cerebellar lesion from the first patient and a spinal lesion from the second patient contained two distinct components. The inner part of these tumors consisted of a nested mass of polygonal clear cells that expressed cytokeratin and epithelial membrane antigen, while the outer part of the tumors showed proliferation of capillaries and intervening foamy stromal cells that were negative for cytokeratin and epithelial membrane antigen. The tumors were thus considered to be hemangioblastomas complicated by metastatic lesions of renal cell carcinoma of clear cell type. These cases indicate that tumor-to-tumor metastasis should be considered when hemangioblastoma contains a clear cell carcinoma component in the setting of VHL disease, and that immunohistochemical staining for cytokeratin and epithelial membrane antigen is useful for the diagnosis.

Biomarkers, Tumor↗
PubMed2001

Evaluation of neurotoxicity of TIQ and MPTP and of parkinsonism-preventing effect of 1-MeTIQ by in vivo measurement of pre-synaptic dopamine transporters and post-synaptic dopamine D(2) receptors in the mouse striatum.

Parkinsonism-inducing neurotoxicity of 1,2,3,4-tetrahydroisoquinoline (TIQ), as contrasted to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), and parkinsonism-preventing effect of 1-methyl-1,2,3,4-tetrahydroisoquinoline (1-MeTIQ) have been investigated in mice by measuring their effects on the in vivo binding of radioligand to pre-synaptic dopamine transporters (DATs) or to dopamine D(2) receptors (D2R) in the striatum. A significant reduction of the ligand-DATs binding was found in the mice treated with MPTP, but not with TIQ, under the dosage inducing behavioral abnormality and loss of tyrosine hydroxylase-positive cells in the substantia nigra. A slight decrease in the ligand-DATs binding was observed in the mice given a larger dose of TIQ. Compensatory up-regulation in the post-synaptic D2Rs was found in the MPTP-treated mice. Pre-treatment with (S)-enantiomer, but not (R)-enantiomer, of 1-MeTIQ prevented the degeneration of DATs to some extent. We concluded that the TIQ-induced parkinsonism model is different from the MPTP-induced model as evaluated by the radioligand-DATs binding and that (S)-1-MeTIQ has a preventing effect for the degeneration of the DATs to a certain extent.

1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
PubMed2001

Mutation of von Hippel-Lindau tumor suppressor gene in a sporadic endolymphatic sac tumor.

Endolymphatic sac tumor (ELST) is a low-grade adenocarcinoma of the temporal bone that is presumed to originate from the endolymphatic system. Although ELSTs are extremely rare in the general population, a significant number of studies have documented the occurrence of ELST among patients with von Hippel-Lindau (VHL) disease. Because of the rarity of the tumor, however, few cases of ELST have been analyzed for mutations of the VHL tumor suppressor gene. In this study, we reported a Japanese male patient with sporadic ELST, along with a molecular genetic analysis of the VHL gene. The light microscopic and immunohistochemical features and clinical presentations were typical of ELST. Sequencing studies of the tumor DNA disclosed a G to T substitution of nucleotide 564, which resulted in an amino acid substitution (Trp to Cys). This is the first report of the VHL gene mutation in a sporadic Japanese case of ELST.

Adenocarcinoma↗
PubMed2001

The role of p27kip1 protein expression on the biological behavior of intrahepatic cholangiocarcinoma.

Recent studies have reported that a decreased p27kip1 protein (p27) expression is associated with aggressive tumor behavior in several human malignancies. In this study, we examined the role of p27 expression in intrahepatic cholangiocarcinoma (ICC) and the noncancerous intrahepatic bile duct epithelium and assessed its association with clinicopathologic features, especially the influence of decreased p27 expression by the tumor on its prognosis as determined by immunohistochemistry. Almost all noncancerous bile duct epithelia show positive nuclear staining and reveal a faintly positive reaction in the cytoplasm. In 62 surgically resected ICCs, a variable degree of positive p27 nuclear staining is recognized. A subset (13 of 62 cases; 21.0%) of the carcinomas displayed cytoplasmic staining. We classified 62 cases into 2 groups, a low expression group (< 50% of p27 nuclear positive cells) and a high expression group (> or = 50% of p27 nuclear positive cells), and tested for the association between positive expression and clinicopathologic features. We found that a low expression of nuclear p27 was correlated with positive vascular invasion (P < .05). The survival curve of the group with low p27 nuclear expression was significantly lower than that of the group with high p27 nuclear expression (P < .005). According to the multivariate analyses, low p27 expression can be considered an independent prognostic factor whose occurrence indicates a worse prognosis. We conclude that a decreased p27 expression adds an independent parameter that can be used when determining the prognosis of patients with ICC.

Bile Duct Neoplasms↗
PubMed2001

Cone-beam image reconstruction using spherical harmonics.

Image reconstruction from cone-beam projections is required for both x-ray computed tomography (CT) and single photon emission computed tomography (SPECT). Grangeat's algorithm accurately performs cone-beam reconstruction provided that Tuy's data sufficiency condition is satisfied and projections are complete. The algorithm consists of three stages: (a) Forming weighted plane integrals by calculating the line integrals on the cone-beam detector, and obtaining the first derivative of the plane integrals (3D Radon transform) by taking the derivative of the weighted plane integrals. (b) Rebinning the data and calculating the second derivative with respect to the normal to the plane. (c) Reconstructing the image using the 3D Radon backprojection. A new method for implementing the first stage of Grangeat's algorithm was developed using spherical harmonics. The method assumes that the detector is large enough to image the whole object without truncation. Computer simulations show that if the trajectory of the cone vertex satisfies Tuy's data sufficiency condition, the proposed algorithm provides an exact reconstruction.

Algorithms↗
PubMed2001

Characterization and cloning of an extremely thermostable, Pyrococcus furiosus-type 4Fe ferredoxin from Thermococcus profundus.

An extremely thermostable [4Fe-4S] ferredoxin was isolated under anaerobic conditions from a hyperthermophilic archaeon Thermococcus profundus, and the ferredoxin gene was cloned and sequenced. The nucleotide sequence of the ferredoxin gene shows the ferredoxin to comprise 62 amino acid residues with a sequence similar to those of many bacterial and archaeal 4Fe (3Fe) ferredoxins. The unusual Fe-S cluster type, which was identified in the resonance Raman and EPR spectra, has three cysteines and one aspartate as the cluster ligands, as in the Pyrococcus furiosus 4Fe ferredoxin. Under aerobic conditions, a ferredoxin was purified that contains a [3Fe-4S] cluster as the major Fe-S cluster and a small amount of the [4Fe-4S] cluster. Its N-terminal amino acid sequence is the same as that of the anaerobically-purified ferredoxin up to the 26th residue. These results indicate that the 4Fe ferredoxin was degraded to 3Fe ferredoxin during aerobic purification. The aerobically-purified ferredoxin was reversibly converted back to the [4Fe-4S] ferredoxin by the addition of ferrous ions under reducing conditions. The anaerobically-purified [4Fe-4S] ferredoxin is quite stable; little degradtion was observed over 20 h at 100 degrees C, while the half-life of the aerobically-purified ferredoxin is 10 h at 100 degrees C. Both the anaerobically- and aerobically-purified ferredoxins were found to function as electron acceptors for the pyruvate-ferredoxin oxidoreductase purified from the same archaeon.

Amino Acid Sequence↗
PubMed2001

Meta-cleavage enzyme gene tesB is necessary for testosterone degradation in Comamonas testosteroni TA441.

Comamonas testosteroni metabolizes testosterone as the sole carbon source via a meta-cleavage reaction. A meta-cleavage enzyme gene, tesB, was cloned from C. testosteroni TA441. The deduced N-terminal amino acid sequence of tesB matched that of the purified meta-cleavage enzyme which is induced in TA441 during growth on testosterone as the sole carbon source. The tesB-disrupted mutant did not show growth on testosterone, suggesting that tesB is necessary for TA441 to grow on testosterone. Downstream from tesB, three putative ORFs which encode products also necessary for growth of TA441 on testosterone were identified. The usual substrate of TesB is probably 3,4-dihydroxy-9,10-secoandrosta-1,3,5(10)-triene-9,17-dione. Although this compound was not identified in the gene disrupted mutants, accumulation of upstream metabolites of testosterone degradation, 4-androstene-3,17-dione and 1,4-androstadiene-3,17-dione, was shown by TLC analysis.

Bacterial Proteins↗
PubMed2001

The effects of vagotomy on the abomasum in calves: radiography and protein gene product 9.5 immunohistochemistry.

Abomasal disorders of calves with total vagotomy, operated on at 1 week old, were investigated with radiography and protein gene product (PGP) 9.5 immunohistochemistry. Radiographic findings indicated abomasal atony with dilatation in all calves 2 weeks after vagotomy, while 4 weeks after vagotomy abomasal dilatation was detected in 2 calves and another 2 calves showed dilatation and impaction. The densities of PGP 9.5-immunoreactive nerves in the tunica muscularis decreased significantly in the corpus region of the greater curvature 2 weeks after vagotomy and in the pyloric region of the lesser curvature 4 weeks after vagotomy, and it was at its lowest 4 weeks after vagotomy in all regions examined. In conclusion, abomasal dilatation and/or impaction in vagotomized calves confirmed by radiography were related with a decreased frequency of nerves in the tunica muscularis of the abomasum.

Abomasum↗
PubMed2001

[Aldolase].

Aldolase (EC 4.1.2.13) plays an important role in glucose metabolism. Aldolase has a molecular weight of 160 kDa and has three isozymes, namely aldolase A, B and C. The enzyme is probably present in all cells; it occurs in particularly large quantities in the muscles, liver and brain. An increase in serum aldolase is found in myotonic muscular disease, such as progressive muscular dystrophy and polymyositis. The enzyme rises in myocardial infarction, reaches a maximum within 24-48 hours and returns to normal in the course of five days. In these muscular diseases, aldolase A isozyme is elevated. Aldolase activity, especially B isozyme, in serum rises to very high levels in acute hepatitis, but is slightly elevated in cirrhosis, chronic hepatitis and obstructive jaundice. Aldolase becomes elevated in serum with malignant tumors, and isozyme A is predominant in serum. Erythrocytes are also rich in aldolase, and the enzyme rises in hemolytic anemia.

Acute Disease↗
PubMed2000

Clinical characteristics of clear cell carcinoma of the ovary: a distinct histologic type with poor prognosis and resistance to platinum-based chemotherapy.

BACKGROUND: A retrospective review of treatment results comparing women with clear cell carcinoma of the ovary (CCC) with a group with serous adenocarcinoma of the ovary (SAC) was conducted. METHODS: Between 1988-1998, 662 patients with epithelial ovarian carcinoma were identified through the medical records department and the tumor registry at 4 institutions. After the central pathologic review, 101 patients with pure or dominant (>/= 90%) CCC (15.3%) were entered into the current study. Two hundred thirty five patients with pure SAC were selected as a group for comparison. All patients underwent staging laparotomy followed by platinum-based chemotherapy. Distribution of the International Federation of Gynecology and Obstetrics (FIGO) disease stage, response to chemotherapy, and prognosis for patients with CCC were compared with the same values in patients with SAC. RESULTS: Patients with CCC were significantly more likely to have FIGO Stage I disease than were patients with SAC (48.5% vs. 16.6%). A high recurrence rate was noted in those patients with Stage IC CCC (37%). In those patients with Stage IC disease, the survival rates for patients with CCC were lower than those for patients with SAC. The 3-year and 5-year survival rates for Stage III CCC patients were significantly lower compared with Stage III SAC patients. The response rate to platinum-based chemotherapy in patients with CCC was significantly lower than that in patients with SAC. CONCLUSIONS: CCC is an intriguing histologic type of epithelial ovarian cancer that demonstrates a clinical behavior distinctly different from that of SAC.

Adenocarcinoma, Clear Cell↗
PubMed2000

Developmental study of the shortened spinal cord in the adult tiger puffer fish, Takifugu rubripes (Teleostei).

ABSTRACT The spinal cords of vertebrates are generally divided into the cord proper and the minute filum terminale. While the spinal cord extends the entire length of the vertebral canal in the adult tiger puffer, Takifugu rubripes, the cord proper is greatly reduced in length and almost all of the canal is occupied by the filum terminale, which is tape-like rather than thread-like. The dorsal and ventral roots of the spinal nerves extend, respectively, above and below the filum terminale; as a whole, these form a massive cauda equina. Supramedullary cells are found in the rostral half of the medulla oblongata caudal to the cerebellum. In 4-mm long tiger puffers, the spinal cord is cylindrical and supramedullary cells are found in the rostral half of the cord. In 7-mm puffers, the longitudinally arranged ventral roots appear ventrally in the middle portion of the spinal cord. In 15-mm puffers, the dorsal and ventral roots run longitudinally along the spinal cord and have noticeably increased in number. Supramedullary cells are located in the rostral 15% of the cord. In 21-mm puffers, the spinal cord in large part becomes dorsoventrally flattened. In 30-mm puffers, the spinal cord becomes much flatter, and supramedullary cells now are located mainly in the medulla oblongata. These observations indicate that formation of the shortened spinal cord proper is due to at least two developmental processes. First, the elongation of the spinal cord proper is remarkably less than that of the vertebral canal. Second, the bulk of the spinal cord proper is translocated to the cranial cavity, where it is transformed into part of the medulla oblongata.

Animals↗
PubMed2000

Piperazine analog of vesamicol: in vitro and in vivo characterization for vesicular acetylcholine transporter.

The probes to detect vesicular acetylcholine transporter (VAChT) in vivo are important to evaluate the mapping and function in cholinergic system. To develop high-specific and high-affinity radiotracer for single photon emission computed tomography, we investigated piperazine analogs which replaced the piperidine ring of (-)-vesamicol with a piperazine ring. We found that the piperazine analog of iodobenzovesamicol, trans-5-iodo-2-hydroxy-3-[4-phenylpiperazinyl] tetralin (DRC140), had high affinity for VAChT in rat brain. We carried out binding assay in subcellular fraction of the rat brain. The highest B(max) for [(125)I]-DRC140 binding was observed in the synaptic vesicle fraction (1,751 fmol/mg protein), followed by the crude vesicle (821 fmol/mg protein) and the P2 fraction (187 fmol/mg protein). These K(d) values were similar to the affinity of highly purified synaptic vesicular fraction (K(d) = 0.3 nM) with a one-site model. The possibility that [(125)I]-DRC140 recognizes sigma receptor was excluded by our finding large inhibition constants (K(i) = 849 nM for haloperidol, K(i) = 3,052 nM for 1,3-di(2-tolyl)guanidine). In vivo distribution studies with the [(123)I]-DRC140 in rats showed a rapid brain uptake. The highest brain area was in striatum, followed by frontal cortex, occipital cortex, and hippocampus. The lowest brain area was cerebellum. The radioactivity of high-accumulated areas in ex vivo autoradiography was reduced by a preinjection of (-)-vesamicol and these levels were reduced to the radioactivity in cerebellum. These results show that [(125)I]-DRC140 can provide extremely high specific tracer with excellent brain permeability as a ligand for single photon emission computed tomography.

Acetylcholine↗
PubMed2000

Does central venous pressure reflect the circulating blood volume for the decrement of compliance just after esophagectomy?

This study investigates whether the pressure parameters obtained from the Swan-Ganz catheter (SGC) accurately reflect the circulating blood volume just after en bloc resection of the thoracic esophagus with regional lymph node dissection. It is well known that this operation induces severe hemodynamic changes and although the pressure parameters obtained from the SGC are an accepted means of monitoring circulating blood volume, we have often experienced a discrepancy between the SGC data and the clinical state. We examined the pressure parameters and diameter of the inferior vena cava (IVC) and left ventricle (LV), and the central venous compliance using SGC and echocardiography in ten patients who underwent esophagectomy for esophageal cancer. The central venous pressure, pulmonary arterial mean pressure, and pulmonary artery wedged pressure were significantly increased just after the operation compared with the preoperative levels, while the diameters of the IVC and LV decreased just after the operation. The compliances of the IVC decreased significantly just after the operation. The hemodynamic shift to the third space after esophagectomy induces decrement of the compliances of IVC. As the CVP does not always reflect the circulating blood volume, measuring the diameter of the IVC using echocardiography is extremely useful for monitoring circulating blood volume just after esophagectomy.

Blood Volume↗
PubMed2000

Biosynthesis of poly(3-hydroxybutyrate-co-3-hydroxyalkanoates) by recombinant bacteria expressing the PHA synthase gene phaC1 from Pseudomonas sp. 61-3.

Pseudomonas sp. 61-3 accumulated a blend of poly(3-hydroxybutyrate) [P(3HB)] homopolymer and a random copolymer consisting of 3-hydroxyalkanoate (3HA) units of 4-12 carbon atoms. The genes encoding beta-ketothiolase (PhbA(Re)) and NADPH-dependent acetoacetyl-CoA reductase (PhbB(Re)) from Ralstonia eutropha were expressed under the control of promoters for Pseudomonas sp. 61-3 pha locus or R. eutropha phb operon together with phaC1(Ps) gene (PHA synthase 1 gene) from Pseudomonas sp. 61-3 in PHA-negative mutants P. putida GPp104 and R. eutropha PHB(-4) to produce copolyesters [P(3HB-co-3HA)] consisting of 3HB and medium-chain-length 3HA units of 6-12 carbon atoms. The introduction of the three genes into GPp104 strain conferred the ability to synthesize P(3HB-co-3HA) with relatively high 3HB compositions (up to 49 mol%) from gluconate and alkanoates, although 3HB units were not incorporated at all or at a very low fraction (3 mol%) into copolyesters by the strain carrying phaC1Ps gene only. In addition, recombinant strains of R. eutropha PHB(-4) produced P(3HB-co-3HA) with higher 3HB fractions from alkanoates and plant oils than those from recombinant GPp104 strains. One of the recombinant strains, R. eutropha PHB(-4)/ pJKSc46-pha, in which all the genes introduced were expressed under the control of the native promoter for Pseudomonas sp. 61-3 pha locus, accumulated P(3HB-co-3HA) copolyester with a very high 3HB fraction (85 mol%) from palm oil. The nuclear magnetic resonance analyses showed that the copolyesters obtained here were random copolymers of 3HB and 3HA units.

Acyltransferases↗