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Biomedical subjects

Y Shibata

Publications and source records attributed to Y Shibata.

At least 541 records · Page 30Linked to original sources
PubMed1991

Mechanism of anti-inflammatory action of etodolac.

The effect of etodolac (CAS 41340-25-4) on the inflammatory reactions induced by histamine and bradykinin was compared with that of indomethacin and other nonsteroidal anti-inflammatory drugs. Etodolac (50 mg/kg p.o.), indomethacin (20 mg/kg p.o.), diclofenac Na (20 mg/kg p.o.) and acetylsalicylic acid (200 mg/kg p.o.) had no effect on the increase of vascular permeability induced by histamine or bradykinin and on passive cutaneous anaphylaxis in rats. Etodolac (5, 10 and 20 mg/kg p.o.) suppressed concanavalin A-induced paw edema in rats. Etodolac (10 mg/kg p.o.) and bromelain (10 mg/kg i.v.) significantly suppressed the heat-induced elevation of bradykinin in perfusates of rat paws, but indomethacin (20 mg/kg p.o.) and diclofenac Na (20 mg/kg p.o.) did not. Etodolac inhibited bradykinin-forming enzyme activity in a concentration-dependent manner (IC50 = 1.5 x 10[-4) mol/l). These results suggest that etodolac is a unique nonsteroidal anti-inflammatory drug which can inhibit bradykinin formation, unlike indomethacin or diclofenac Na.

Animals↗
PubMed1991

[Autologous blood transfusion with recombinant human erythropoietin in heart surgery--studies on the volume of preoperative donation and postoperative administration].

Recombinant human erythropoietin (rHuEPO) was administered to 42 elective heart surgery patients, and the volume of autologous blood donated within the preoperative short period and effects of improving anemia by postoperative rHuEPO administration were studied. rHuEPO (100 U/kg/day) and chondroitin sulfate-iron (40 mg/day) were given intravenously for preoperative 14 days, and each 400 ml of autologous blood was donated on the 14th and 4th day before operation. Reticulocytes increased significantly 3 days after administration (p less than 0.01). The hemoglobin level, 13.4 +/- 1.0 g/dl before the first donation, returned to 13.4 +/- 1.1 g/dl just before operation. 800 ml of autologous blood, needed for usual open heart surgery, may possibly have been donated within 14 days without making patients anemic by intravenous rHuEPO administration. For postoperative rHuEPO administration, the patients were divided into 3 groups: Group I (10 cases): given for 14 days, Group II (12 cases): for 7 days, Group III (20 cases): no administration. Reticulocytes decreased rapidly after termination of rHuEPO administration in each group, and on the 7th day after termination, they returned to the level before administration. The hemoglobin level in Group I was maintained after termination of rHuEPO, and was +2.2 +/- 1.1 g/dl on the 21st postoperative day compared with the level of 1st postoperative day. The hemoglobin level in Group II fell after termination and was +0.9 +/- 0.7 g/dl on the 21st day, this being comparable to the level of Group III. There were significant differences between Group I and II (p less than 0.05), and between Group I and III (p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1991

[Duodenal varices treated successfully by percutaneous transhepatic obliteration: report of a case].

A 73-year-old female with bleeding from duodenal varices treated by percutaneous transhepatic obliteration (PTO) was reported. She was admitted to our hospital because of tarry stool and general malaise. Gastroduodenoscopy revealed tortous elevations in the descending part of the duodenum, and observed intermittent bleeding. Percutaneous transhepatic portography (PTP) was carried out. PTP revealed duodenal varices supplied via the inferior pancreaticoduodenal vein and drained to the inferior vena cava, and continuously obliterated by gelfoam. Duodenal varices disappeared after obliteration and we observed no recurrence of varices for a year endoscopically. In general, it is accepted that the causes of the upper gastrointestinal bleeding secondary to portal hypertension are esophagogastric varices, hemorrhagic gastritis, gastro-duodenal ulcer, and so on. However, we must keep in mind the case with duodenal varices in which bleedings are of unknown origin. We also reviewed duodenal varices reported in Japanese literature from 1968 to 1989.

Aged↗
PubMed1991

[Intracardiac repair in left ventricular rupture following mitral valve replacement].

Rupture of the left ventricle is one of the major lethal complications of mitral valve replacement. We have encountered 11 cases of this complication over a period of 19 years (1971, Apr.-1990, Mar.). Five of 8 cases of intraoperative rupture survived but no patient survived a delayed rupture. In the patients with intraoperative rupture external repair was performed in 6 cases, resulting in 3 survivors, two in type II and one in type I with formation of left ventricular false aneurysm. For selection of surgical treatment accurate recognition of types of rupture is important but the location and size of the endocardial and epicardial defects do not always correspond. Attempts to suture a ventricular rupture on the pressure-loaded beating heart were always unsuccessful and frequently extended the tear. Repair should be accomplished with aid of cardiopulmonary bypass on the decompressed and arrested heart. Recently, we chose internal repair with arrested heart in 2 cases of type I rupture, that is, reopening of the left atrial closure and repair from within the cardiac chamber with removal of the prosthetic valve. Both cases survived. In conclusion, we emphasized importance of intracardiac repair with removal of the replaced prosthetic valve in left ventricular rupture of type I and III following mitral valve replacement for better exposure, more secure repair, and prevention of injury to the circumflex artery.

Adult↗
PubMed1990

The effects of ablation of the visual cortical area on the formation of LTP in the superior colliculus of the rat.

Postsynaptic potentials (PSPs) were recorded on the surface of the rat in the superior colliculus (SC) after electrical stimulation of the optic nerve. Long-term potentiation (LTP) was elicited in the PSP by tetanic stimulation of the optic nerve either when the ipsilateral visual cortex was removed or when a GABA antagonist, picrotoxin, was administered before the tetanic stimulation. These results suggest that the corticotectal tract may inhibit the appearance of LTP via the GABAergic interneurons within the superficial gray layer (SGL).

Animals↗
PubMed1990

Involvement of a protein kinase C-dependent process in long-term potentiation formation in guinea pig superior colliculus slices.

Superior colliculus (SC) slices were prepared from guinea pig. Electrical stimulation was applied to the optic layer (OL) of the SC slices and the postsynaptic potential (PSP) was evoked in the superficial grey layer (SGL) of the SC. Tetanic stimulation to the OL evoked long-term potentiation (LTP) in the PSP. To investigate the involvement of the protein kinase C (PKC) system on the LTP formation in the SC, the effects of PKC activator (phorbol ester) and PKC inhibitors (polymyxin B, melittin and H-7) on the LTP formation have been studied. Application of phorbol ester to the medium at concentrations between 10(-8) and 10(-10) M increased the amplitude of the PSP. On the other hand, the presence of phorbol ester at a concentration of 10(-6) M increased the glutamate release from the SGL slices. Tetanic stimulation which could not induce LTP by itself could elicit LTP during application of phorbol esters at the low concentration (3 X 10(-12) M). PKC inhibitors such as polymyxin B (10(-7) M), melittin (10(-8) M) and H-7 (10(-4) M) prevented LTP formation. When H-7 was applied once after LTP was formed, the enhanced PSP reduced to the original level. These results strongly indicate the involvement of PKC system on the LTP formation in the SC slices.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1990

Calcium ionophore but not phorbol ester promotes eicosanoids release by proliferating interleukin-3-dependent bone marrow cells.

Eicosanoid release during multilineage hematopoiesis was assessed using freshly isolated mouse bone marrow cells cultured in the presence of interleukin-3 (IL-3) (10% WEHI-3 culture-conditioned medium). Cells that could release prostaglandin E2 (PGE2) when stimulated with calcium ionophore A23187, but not with phorbol ester (PMA), appeared within 4 days. The cells harvested on day 10 released 42 ng of PGE2/10(6) cells/mL after A23187 stimulation. Leukotriene B4 (LTB4) (4 ng/mL) was also detected after A23187 stimulation, but there was no detectable LTC4 (less than 0.5 ng/mL). Nonadherent bone marrow cells were isolated from 28-day cultures and cloned. All clones were strongly IL-3-dependent. Although other growth factors such as granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage CSF (GM-CSF), and CSF-1 failed to promote survival or support proliferation of the cells, three clones (11-1-A6, 3-2-D5, and 11-1-A1) showed significant increases in 3H-thymidine incorporation, respectively, after PMA treatment for 24 hours. Surviving cells displayed dominantly myeloid type morphology and phenotypic characteristics. The data suggest that IL-3 is important in the formation of PGE2-producing cells. In contrast to many macrophages (MO), neither the IL-3-dependent cell lines nor the IL-3-cultured bone marrow cells released significant amounts of PGE2 when stimulated with PMA or IL-3, although PMA and IL-3 both induced translocation of protein kinase C (PKC) to the membrane fraction. The lack of production of PGE2 and other eicosanoids by the PMA- and IL-3-stimulated cell lines was confirmed by measuring the release of 3H-arachidonic acid. The data suggest that in IL-3-dependent bone marrow cell lines the activation of eicosanoid metabolism requires elevated cellular Ca2+; PKC activation alone does not appear to be a sufficient stimulus.

Animals↗
PubMed1990

Synthesis and biological activities of methyl oligobiosaminide and some deoxy isomers thereof.

Methyl oligobiosaminide (1) the core structure of oligostatin C, and five analogues, the 6-hydroxy-(2), 2-deoxy- (3), 2-deoxy-6-hydroxy- (4), 3-deoxy- (5), and 3-deoxy-6-hydroxy derivatives (6), were synthesized by coupling the protected pseudo-sugar epoxide 46 with suitable methyl 4-amino-4-deoxy-alpha-D-hexopyranoside derivatives. Compounds 3 and 6 showed notable inhibitory activity against alpha-D-glucosidase and alpha-D-mannosidase, respectively, whereas compound 1 had almost no activity.

Carbohydrate Sequence↗
PubMed1990

The ultrastructure of the supporting system in the guinea pig semicircular canal.

The ultrastructure of the perilymphatic space of the guinea pig semicircular canal was examined, using thin sectioning, scanning electron microscopy and freeze-fracture methods. The perilymphatic space was divided into two parts: an area of fibrous matrix and an area of fibroblasts with bundles of fine filaments. In the area of fibroblasts, cell processes and filament bundles formed a meshed pattern. The cell processes were interconnected with each other by both intermediary and gap junctions. The inner surface of the osseous semicircular canal was covered with multilayers of cell processes of both fibroblasts and mesothelial cells. The fact that tight and gap junctions were observed between the cell processes suggests a functional significance in these structures.

Animals↗
PubMed1990

CD28 molecule as a receptor-like function for accessory signals in cell-mediated augmentation of IL-2 production.

IL-2 production by PHA-stimulated MOLT 14 cells (a TcR gamma/delta-bearing human leukemic T cell line) and MOLT 16 cells (a TcR alpha/beta-bearing human leukemic T cell line) was markedly augmented by coculturing with BALL-1 cells ( a human leukemic B cell line), or with recombinant human interleukin-1 alpha (rhIL-1 alpha). We have previously shown that the augmentation of IL-2 production, induced by BALL-1 cells, requires cell to cell contact and is an IL-1-independent pathway. In this report, the expression of the CD28 molecule on MOLT 14 cells and MOLT 16 cells was examined for its role in IL-2 production augmented by BALL-1 cells. A 1-hr preincubation of MOLT 14 cells and MOLT 16 cells with anti-CD28 mAb resulted in the inhibition of BALL-1 cell-induced augmentation of IL-2 production (90 and 62% inhibition of control, respectively). The inhibition was observed in a dose-dependent manner of anti-CD28 mAb added and reached a plateau level at concentrations of 0.05 micrograms/ml of anti-CD28 mAb. This was sufficient to cover all the CD28 molecules expressed on the surface of both T cells as detected by flow cytometric analysis. Flow cytometric analysis also showed that the inhibition was not due to a modulation of CD28 molecules. In contrast, the treatment with anti-CD28 mAb did not inhibit IL-2 production which was augmented by rhIL-1 alpha costimulator. These results suggest that the CD28 molecule on the T cells is important for the interaction with BALL-1 cells which causes the augmentation of IL-2 production and further imply that the CD28 molecule is a receptor for an accessory signal provided by BALL-1 cells.

Antibodies, Monoclonal↗
PubMed1990

Fragmentation of re-formation of mitotic Golgi apparatus detected by a centrifugal method.

The fragmentation/re-formation process of the Golgi apparatus during mitosis was studied by flotation centrifugation in a stepwise sucrose density gradient. The mitotic Golgi fraction was obtained from Chinese hamster ovary cells synchronized with thymidine and nocodazole. The Golgi apparatus detected by a marker enzyme, galactosyltransferase, was separated into two peaks by the flotation centrifugation. The amount of the Golgi recovered at the lower density peak was less in the mitotic cells than in the interphase cells. The separation profile of the mitotic Golgi returned to that of the interphase Golgi by further incubation of the mitotic cells. The re-formation of the fragmented Golgi was inhibited by nocodazole and vinblastine, but not by actinomycin D and cycloheximide.

Animals↗
PubMed1990

An ultrastructural study of the guinea pig tectorial membrane 'type A' protofibril.

Fine structural features of the 'type A' protofibrils in the guinea pig tectorial membrane were examined using negative staining and deep-etching techniques. Negative-stained samples of fragmented tectorial membrane were composed of several fine filamentous subunits showing the clear banding pattern of the type A protofibrils. Deep-etched replicas of the EGTA (ethylene glycol bis-N,N,N',N'-tetraacetic acid)-treated samples showed fine surface structure consisting of several linear arrays of filamentous elements on the extracellular fibrils, which is interpreted to be type A protofibrils.

Animals↗
PubMed1990

Characterization of the product of the gtfS gene of Streptococcus downei, a primer-independent enzyme synthesizing oligo-isomaltosaccharides.

The gtfS gene, coding for a glucosyltransferase which synthesizes water-soluble glucan and previously cloned from Streptococcus downei strain MFe28 (mutans serotype h) into a bacteriophage vector, was subcloned into a plasmid vector. The gtfS gene products expressed in Escherichia coli were compared to the primer-independent, oligo-isomaltosaccharide synthase in Streptococcus sobrinus strain AHT (mutans serotype g) and shown to resemble it closely in molecular mass, isoelectric point, immunological properties, optimum pH and Km values. The glucans produced from sucrose by the gtfS gene products are alpha-1,6-linked linear oligo-isomaltosaccharides without any branching sites. A similar gtfS gene was also detected on chromosomal DNA from S. sobrinus strain AHT.

Blotting, Western↗
PubMed1990

Demonstration of the heterogeneity of epitopes of the platelet-specific alloantigen, Baka.

It is well known that the platelet-specific alloantigen, Baka is carried on glycoprotein (GP) IIb, but little is known about the biochemical characteristics of its epitopes. To clarify the characteristics of the epitopes, we examined the interaction of four anti-Baka sera (Yam, Lin, Kl and MO) with their epitopes, either with or without modifications by sodium dodecyl sulphate (SDS) and/or neuraminidase. By immunoprecipitation, all four antisera bound to the intact GP IIb/IIIa complex from a Baka-positive subject. In contrast, immunoblotting demonstrated that Yam, Lin and Kl bound to SDS-denatured GP IIb, while MO did not. When blotted GP IIb was treated with neuraminidase, Yam and Lin did not bind to desialylated GP IIb, while Kl still did. When the purified GP IIb/IIIa complex or washed platelets were treated first with neuraminidase followed by immunoblotting, the molecular weight of GP IIb decreased from 145 kD to 138 kD; Yam did not bind to desialylated GP IIb, but Kl did. Furthermore, to eliminate the effect of SDS, we examined the interaction of Yam and Lin with neuraminidase-treated platelets using flow cytometry. The results were the same as those obtained using immunoblotting. Our results thus demonstrate that the expression of the Baka epitopes is not uniform and that sialic acid contributes to the expression of some actual allogenic epitopes.

Antigen-Antibody Reactions↗
PubMed1990

Autoantibodies to keratin in Sjögren's syndrome.

In order to determine which components of the salivary duct cells are recognized by the antisalivary duct antibodies, sera of patients with Sjögren's syndrome were screened for immunoreactivity to keratin by using an ELISA test and a Western blot analysis. The autoantibodies which reacted with keratin were demonstrated in 8 of 9 definite cases of Sjögren's syndrome and in 3 of 6 probable cases, and they reacted with different keratin peptides in each case. The results suggest that the antisalivary duct antibodies include antibodies against keratin, which exists ubiquitously as a cytoskeleton in the salivary gland epithelial cells. Detection of antikeratin antibody might be a useful aid for diagnosis of Sjögren's syndrome.

Adult↗
PubMed1990

Radiosensitivity of macrophage colony-forming cells-implications for their heterogeneity.

We compared the radiosensitivity of macrophage (M) colony-forming cell (CFC) in and outside the hemopoietic bone marrow. Murine bone marrow cells (BMC) are stimulated by either macrophage colony-stimulating factor (CSF-1) or murine recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) to form M- and granulocyte- macrophage (GM) colonies on soft agarose medium, whereas both peritoneal exudate cells (PEC) and pulmonary alveolar macrophages (PAM) also have a capacity to make only M- colonies either by rGM-CSF or CSF-1. The clonal growth of peritoneal exudate CFC (PE-CFC) and alveolar macrophage CFC (AL-CFC) was more effectively achieved with rGM-CSF, and their cloning efficiencies were much higher than bone marrow CFC (BM-CFC). Following in vitro exposures to gamma-irradiation (1Gy/min), the dose-survival response of each M-CFC grown by cultures with either rGM-CSF or CSF-1 indicates that the radiosensitivity was the highest in BM-CFC, whereas Al-CFC was more radioresistant than PE-CFC. Surface antigen expression, such as macrophage-specific F4/80, on these CFCs, was invariable before or after irradiation except that it was diminished on irradiated PE-CFC. These results indicate the heterogeneity of tissue M-CFCs in their radiosensitivities as well as in responsiveness to CSFs.

Animals↗
PubMed1990

Acute megakaryoblastic leukemia in Down syndrome, following thrombocytopenia with antiplatelet antibody.

We report a case of acute megakaryoblastic leukemia (AMKL) with antiplatelet antibody in a boy with Down syndrome. When the patient was admitted, his platelet count was 1.3 X 10(4)/mm3 and antiplatelet antibody in the plasma was detected. Two months after admission, blasts, which showed positive reaction to both antiplatelet monoclonal antibody and platelet peroxidase, increased.

Autoantibodies↗