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Biomedical subjects

Y Takeuchi

Publications and source records attributed to Y Takeuchi.

At least 667 records · Page 37Linked to original sources
PubMed1992

[Early diagnosis and management against perioperative fungus infection].

Candida spp. is frequently detected from perioperative patients, especially from those requiring central venous catheter (CVC) management. CAND-TEC could detect the blood fungus infection easily and quickly. We analyzed 438 specimens from 57 patients requiring perioperative CVC management for more than three weeks, and investigated usefulness of CAND-TEC comparing with other serological methods. The dilution rate of CAND-TEC showed a positive correlation with amount of beta-D-glucan which was measured by Toxicolor test and Endotoxin-specific assay. It also showed a positive correlation with amount of D-arabinitol. When blood samples diluted more than four times were positive with CAND-TEC, the patients were considered to be infected, and accumulative infection rate was up to 84.2% three weeks after introduction of CVC management. CAND-TEC would be useful in detecting Candida infection compared with conventional methods, and the fungus infection was much more frequent incidence than ever expected. It is important to detect fungus infection early and respond immediately to avoid nosocomial infection.

Candidiasis↗
PubMed1992

[Left atrial myxomas: clinical characteristics, evaluation and considerations in classifying tumors].

Eleven patients underwent surgical excision for left atrial myxomas. Clinical symptoms, coronary angiographic findings and operative procedures were evaluated. Myxomas were classified into two types based on macroscopical findings, and clinical characteristics of these two types were analyzed. Seven cases (64%) classified as "lobular-type myxomas" were seen as lobulated, gelatinous and fragile. Four cases (36%) were classified as "round-type myxomas" were round and elastic soft. Primary symptoms included dyspnea on exertion in five cases (45%) and neurological disturbances in six cases (55%). Brain emboli were found in four patients by CT scan, and were classified as lobular-type myxomas. These eleven myxomas successfully removed in all cases. Four of these myxomas, which were pedunculated with fine fibrous stalks, were shaved along the base at the atrial septum or free wall. Others were excised completely along with a portion of the adjacent septum. Microscopic examination of the operative specimens revealed that two lobular-type myxomas with broad-based attachment to left atrial septum had invaded the atrial septum. All patients are doing well and have had no signs of myxoma recurrence at postoperative periods ranging from 10 months to 12 years (mean follow-up 5.3 years). Seven patients underwent selective coronary angiography due to a diagnosis of a coronary artery disease. All coronary angiograms were normal in all cases. In five (71%) of these seven, abnormally dilated atrial branches were seen as supplying the tumor. In two cases with round-type myxomas, neovascularity was evident and was made up of clusters of tortuous vessels with tumor blush.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1992

[An emergency surgical case of double aortic arch with hemoptysis].

A 78-year-old man was admitted because of hemoptysis. CT and aortogram revealed double aortic arch. Bronchofiberscopy revealed intratracheal hemorrhage which was associated with right aortic arch. An emergency operation was performed to prevent massive intra-tracheal bleeding. The patient underwent ligation of the right aortic arch through median sternotomy. After operation, hemoptysis disappeared and the postoperative course was uneventful. Surgical cases of double aortic arch are rare, especially with critical hemoptysis in aged patients.

Aged↗
PubMed1992

Establishment of an experimental model of autoimmune epididymo-orchitis induced by the transfer of a T-cell line in mice.

A murine T-cell line derived from BALB/c mice (designated B.T.1) was established which was capable of adoptively transferring experimental autoimmune orchitis (EAO) in normal recipients. The protocol consisted of preparing lymphocytes obtained from the mice that were immunized with syngenetic testicular germ cells (TGC) and the subsequent repeated selection of the lymphocytes in vitro by stimulation with murine testicular antigens (mTA). Phenotypic analysis revealed that B.T.1 cells were CD4+ T-cells. Intra-peritoneal inoculation of as few as 1 x 10(5) B.T.1 cells, that were stimulated in vitro with mTA before the inoculation, was capable of transferring EAO to naive recipients. In the latter, both delayed type hypersensitivity (DTH) and humoral responses to TGC were augmented. The transferred lesion was characterized by infiltration of inflammatory cells into the epididymis and rete testis and widespread aspermatogenesis in the testis. The transfer of EAO was unsuccessful when the recipients received B.T.1 cells that were maintained in culture medium without stimulation with mTA. In these recipients, anti-TC DTH was not detected, although the specific humoral response was observed. In-vitro characterization of the biological activity of B.T.1 cells revealed that the line had no cytolytic activity against TGC but the culture supernatant had macrophage migration inhibitory activity involved in the DTH response. Therefore, the DTH responsiveness transferred by B.T.1 cells was found to correlate with their orchitis-inducing capacity.

Animals↗
PubMed1992

[A case report of thrombosed Björk-Shiley valve in aortic position diagnosed using transtelephone PCG monitoring].

We report a successful elective re-AVR and MVR 10 years after AVR with aortic root enlargement and OMC. The patient was a 41-year-old woman. The diagnosis of thrombosed Björk-Shiley (B-S) valve was first suspected by transtelephone PCG monitoring and reconfirmed by the frequency analysis of prosthetic valve sounds and the aortography preoperatively. The thrombosis was 15 x 8 x 6.5 mm in size and located at the minor orifice of B-S valve, extending to the strut. The transtelephone PCG was useful in analyzing prosthetic valve sounds for patients especially living away from the hospital.

Adult↗
PubMed1992

Early monoaminergic dysfunction.

The chemical anatomy of the Rett syndrome and experimental studies concerning early monoaminergic lesions were overviewed. An early monoaminergic dysfunction is a likely occurrence for the mechanism underlying the Rett syndrome. For assessing the alteration of monoamine neuron system, 1) regional vulnerability, 2) age-dependent vulnerability and 3) interaction between the monoamine neuron systems should be considered.

Animals↗
PubMed1991

[Diagnostic accuracy of breast sonography. Comparison among three different techniques].

Mechanical arc scanning is widely used for breast sonography in Japan. The authors have used three different kinds of devices over the past seven years. The diagnostic accuracy was compared among three groups of patients with pathologically confirmed breast masses. In group A, 309 cases (77 carcinomas) were evaluated with a 10 MHz contact compound scanner, and the sensitivity, specificity and accuracy rates were 77.9%, 97.8% and 92.9%, respectively. In group B, 306 cases (56 carcinomas) were evaluated with a 5 or 7.5 MHz mechanical arc scanner, and the sensitivity, specificity and accuracy rates were 89.3%, 84.8% and 85.6%, respectively. In group C, 296 cases (71 carcinomas) were evaluated with a 7.5 MHz real time scanner, and the sensitivity, specificity and accuracy rates were 95.8%, 92.4% and 93.2%, respectively. In cases with T1 breast cancer, the methods had sensitivities of 60.0%, 85.7% and 94.5%, respectively. The sensitivity of the real-time scanner was not significantly different from that of the mechanical arc scanner. In conclusion, the hand-held real-time scanner with high-frequency transducer is a simple, useful device with high diagnostic accuracy for breast examination and can be used as a substitute for the mechanical arc scanner.

Breast↗
PubMed1991

N-methyl-D-aspartate, quisqualate and kainate receptors are all involved in transmission of photic stimulation in the suprachiasmatic nucleus in rats.

In order to clarify the neuronal transmission mechanism of photic stimulation in the suprachiasmatic nucleus (SCN), the effects of agonists and antagonists for excitatory amino acid receptors on N-acetyltransferase (NAT) activity in the pineal gland were observed following the microinjection of drugs into both sides of the nuclei. N-Methyl-D-aspartate (NMDA), alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionate, and kainate (which are selective agonists for three different subtypes, i.e. NMDA, quisqualate and kainate receptors, respectively) significantly decreased NAT activity similarly to the suppressive effect of light. Moreover, compared with a control group, all the groups pretreated with a selective competitive antagonist for NMDA receptor (D-2-amino-5-phosphonovalerate or 3-((+-)-2-carboxypiperazine-4-yl)-propyl-1-phosphonate), or a selective non-competitive antagonist for non-NMDA receptors (Joro spider toxin-3 or 1-naphthylacetyl spermine) partially blocked the suppressive effect of photic stimulation on NAT activity. These results suggest that NMDA, quisqualate and kainate receptors are all involved in mediating photic stimulation in the SCN.

Acetyltransferases↗
PubMed1991

Effects of 6-hydroxydopamine lesions of the nigrostriatal pathway on striatal serotonin innervation in adult rats.

The effects of 6-hydroxydopamine lesions of the nigrostriatal pathway on striatal serotonin (5-HT) innervation have been examined using immunohistochemistry in adult rats. One day after lesioning, a large number of swollen and densely stained 5-HT-immunoreactive fibers appeared around the lesion which was almost completely void of 5-HT-immunoreactivity. Four weeks after lesioning, a significant reduction in 5-HT innervation density was verified in the ventral portion of the rostral neostriatum and in the caudal neostriatum of the lesioned side. Eight weeks after lesioning, a similar decrease in 5-HT innervation density was observed in the neostriatum on the lesioned side. Some aberrant 5-HT-immunoreactive fibers were found around the lesion of the nigrostriatal pathway. These results indicate that 6-hydroxydopamine lesions of the nigrostriatal bundle of adult rats induce a reduction in striatal serotonin innervation density as well as aberrant morphology of 5-HT-immunoreactive fibers around the lesion.

Animals↗
PubMed1991

Monoclonal antibody against actin cross-reacts with the Thy-1 molecule and inhibits lymphocyte function-associated antigen-1 dependent cell-cell interaction of T cells.

To assess the molecular mechanisms involved in cell-cell interactions of T cells, we produced a mAb that could block PMA-induced homotypic T cell aggregation. The established mAb (TN14 mAb) showed an inhibitory effect on T cell aggregation as large as that of mAb against lymphocyte function-associated Ag-1. TN14 mAb showed a strong reactivity with cell surface molecules on T cells, whereas it did not react with any cell surface Ag on macrophages, B cells, bone marrow cells, or WEHI 164 cells, which were used for immunization. However, all cell lysates could react with TN14 mAb in Western blotting analysis, indicating that TN14 mAb recognized some cytoplasmic protein. From biochemical analysis, TN14 mAb was demonstrated to react with the 43-kDa cytoskeletal protein actin. Moreover, from an immunoprecipitation study, TN14 mAb was demonstrated to cross-react with the Thy-1 molecule on T cells. The binding activity of TN14 mAb with the Thy-1 molecule on T cells was strongly blocked by the addition of purified actin, indicating that TN14 mAb recognized an actin-related epitope of the Thy-1 molecule. TN14 mAb blocked not only T cell aggregation but also cell-mediated cytotoxicity by CTL. These results strongly support the hypothesis that the Thy-1 molecule, a member of the Ig superfamily, may play an important role in cell-cell interactions of T cells.

Actins↗
PubMed1991

Refined crystal structure of the complex of subtilisin BPN' and Streptomyces subtilisin inhibitor at 1.8 A resolution.

The crystal structure of subtilisin BPN' complexed with a proteinaceous inhibitor SSI (Streptomyces subtilisin inhibitor) was refined at 1.8 A resolution to an R-factor of 0.177 with a root-mean-square deviation from ideal bond lengths of 0.014 A. The work finally established that the SSI-subtilisin complex is a Michaelis complex with a distance between the O gamma of active Ser221 and the carbonyl carbon of the scissile peptide bond being an intermediate value between a covalent bond and a van der Waals' contact, 2.7 A. This feature, as well as the geometry of the catalytic triad and the oxyanion hole, is coincident with that found in other highly refined crystal structures of the complex of subtilisin Novo, subtilisin Carlsberg, bovine trypsin or Streptomyces griseus protease B with their proteinaceous inhibitors. The enzyme-inhibitor beta-sheet interaction is composed of two separate parts: that between the P1-P3 residues of SSI and the 125-127 chain segment (the "S1-3 site") of subtilisin and that between the P4-P6 residues of SSI and th 102-104 chain segment (the "S4-6 site") of subtilisin. The latter beta-interaction is unique to subtilisin. In contrast, the beta-sheet interaction previously found in the complex of subtilisin Novo and chymotrypsin inhibitor 2 or in the complex of subtilisin Carlsberg and Eglin C is distinct from the present complex in that the two types of beta-interactions are not separate. As for the flexibility of the molecules comprising the present complex, the following observations were made by comparing the B-factors for free and complexed SSI and comparing those for free and complexed subtilisin BPN'. The rigidification of the component molecules upon complex formation occurs in a very localized region: in SSI, the "primary" and "secondary" contact regions and the flanking region; in subtilisin BPN', the S1-3 and S4-6 sites and the flanking region.

Bacterial Proteins↗
PubMed1991

A possible mechanism of mitochondrial dysfunction during cerebral ischemia: inhibition of mitochondrial respiration activity by arachidonic acid.

The dramatic increase in the arachidonic acid (AA) level in the brain is a well-known molecular event during cerebral ischemia. As mitochondria are known to be one possible site of the cell damage, the effects of AA on the respiratory activity of rat brain mitochondria were investigated in vitro using an oxygen electrode. In NAD-linked respiration, respiratory control ratio was decreased significantly by AA, with an IC50 of 6.0 microM. AA had the dual effect on mitochondrial respiration, a decrease in state 3 and uncoupled state and an increase in state 4 (i.e., uncoupling) as reported by Hillered and Chan (J. Neurosci. Res. 19, 94-100, 1988). Furthermore, we found that other unsaturated long-chain free fatty acids (C18:1-C18:3, C20:1-C20:5) also showed such a dual effect. Cyclooxygenase metabolites of AA such as prostaglandins (D2, E2, F2 alpha, E1) and thromboxane B2, and lipoxygenase metabolites such as leukotrienes (D4, B4) and 5- or 12-hydroperoxyeicosatetraenoic acid had no significant effect. The inhibition of the uncoupled state by AA was more marked in NAD-linked than that in FAD-linked respiration, while the degree of uncoupling by AA were the same in both respirations. In spectrophotometrical measurement, the reduction of cytochromes and flavo-protein was markedly inhibited by AA in NAD-linked respiration, but not in the FAD-linked one. In addition, the activity of cytochrome c oxidase was scarcely inhibited by AA. These data suggest that AA itself, not its metabolites, may inhibit mitochondrial ATP production during brain ischemia and that AA may act on the site(s) closely related to NAD-linked respiration, but not the FAD-linked one, in addition to its uncoupling effect.

Animals↗
PubMed1991

Selective inhibition of NADH-CoQ oxidoreductase (complex I) of rat brain mitochondria by arachidonic acid.

The effects of arachidonic acid on the enzyme complexes in the electron transport system were investigated using submitochondrial particles from rat brain. Arachidonic acid irreversibly inhibited NADH-CoQ oxidoreductase (complex I) activity, but had no effect on the activities of succinate-CoQ oxidoreductase (complex II), CoQH2-cytochrome c oxidoreductase (complex III), cytochrome c oxidase (complex IV), ATPase (complex V), glutamate dehydrogenase, and malate dehydrogenase up to 50 microM. The inhibition was dose-dependent with an IC50 value of 110 nmol/mg protein. The Lineweaver-Burk plot revealed that the inhibition by arachidonic acid was noncompetitive against CoQ with a Ki value of 33 microM and uncompetitive against NADH with a Ki value of 22 microM.

Animals↗
PubMed1991

Serotonergic sprouting in the neostriatum after intrastriatal transplantation of fetal ventral mesencephalon.

The sprouting of serotonergic fibers into the neostriatum of 6-OHDA-lesioned rats should be considered, when assessing the functional aspects of ventral mesencephalic grafts. The degree of serotonergic fiber growth into the neostriatum of rats subjected to unilateral 6-OHDA lesions followed by fetal ventral mesencephalic grafts was examined immunohistochemically. As a measure of serotonergic innervation density, the total length of immunoreactive fibers was quantified as percent area. Four weeks after transplantation, there was complete recovery of (+)-amphetamine-induced rotation. All of the ventral mesencephalic grafts contained serotonin-immunoreactive cells, but much fewer in number than the tyrosine hydroxylase-positive cells found in the same grafts. However, there was significant serotonergic hyperinnervation throughout the transplanted neostriatum compared with the control side. The hyperinnervation derived from the grafted neurons was most marked in the dorsal and lateral sectors of the rostral neostriatum. At 24 weeks after transplantation, the implanted neostriatum still showed a dense serotonergic innervation.

Amphetamine↗
PubMed1991

Stimulation of atrial natriuretic peptide secretion and synthesis by Na-K-ATPase inhibitors.

Ouabain has been reported to increase the secretion of ANP in vitro. In this study, we focused on whether this action is common in Na-K-ATPase inhibitors (ATPI) and whether ATPI simply increase the release of ANP or stimulate both its biosynthesis and release. The effects of ouabain and digoxin on secretion of ANP and accumulation of ANP mRNA were investigated in the rat cardiocyte superfusion system. Ouabain and digoxin increased the immunoreactive ANP (iANP) output into perfusate and accumulation of ANP mRNA significantly. These results suggest that ATPI may stimulate both ANP biosynthesis and release in vitro.

Animals↗
PubMed1991

Identification of heparan sulfate proteoglycan as a high affinity receptor for acidic fibroblast growth factor (aFGF) in a parathyroid cell line.

We have characterized two high affinity acidic fibroblast growth factor (aFGF) receptors in a rat parathyroid cell line (PT-r). Affinity labeling with 125I-aFGF showed that these two receptors, apparent molecular masses, 150 and 130 kDa, respectively, display higher affinity for aFGF than for bFGF. The 150-kDa receptor bears a heparan sulfate chain(s), demonstrated by a decrease in size of 15-20 kDa with heparitinase digestion after affinity labeling. Heparitinase digestion before affinity labeling markedly reduced the intensity of the 150 kDa species. Scatchard analysis showed two different high affinity binding sites (Kd of 3.9 pM with 180 sites/cell and Kd of 110 pM with 5800 sites/cell). The higher affinity site was completely eliminated by digestion with heparitinase before adding labeled aFGF; the lower affinity site was unaffected. In ion exchange chromatography after metabolic labeling of the cells with [3H]glucosamine and affinity labeling with 125I-aFGF, the larger receptor-ligand complex, 165 kDa, eluted with approximately 0.5 M NaCl, typical eluting conditions for heparan sulfate proteoglycans. Both of the receptor-ligand complexes were smaller on sodium dodecyl sulfate-polyacrylamide gel electrophoresis than two major heparan sulfate proteoglycans, HSPG I and II, which we characterized in this cell line previously (Yanagishita, M., Brandi, M. L., and Sakaguchi, K. (1989) J. Biol. Chem. 264, 15714-15720). Both receptors have similar N-linked oligosaccharide and sialic acid contents, shown by analysis of affinity-labeled receptors upon digestion with glycopeptidase F and with neuraminidase. All together, these results suggest that PT-r cells bear two distinct high affinity receptors for aFGF, a 150-kDa receptor which is a heparan sulfate proteoglycan and another that is a glycoprotein. The heparan sulfate glycosaminoglycan moiety of the 150- kDa receptor is critical for high affinity binding of aFGF. These findings contrast with current concepts derived from other systems, suggesting that heparan sulfate glycosaminoglycans/proteoglycans function as a reservoir source for FGF or as a group of low affinity binding sites.

Animals↗