Surgical treatment for massive gastrointestinal bleeding caused by thrombotic thrombocytopenic purpura: a case report.
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Adult↗
Biomedical subjects
T Yoshioka
Publications and source records attributed to T Yoshioka.
The recent activities of the Japan Poison Information Center.
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Female↗
[Augmented antitumor efficacy of combination chemotherapy of nedaplatin with 5-fluorouracil in in vivo murine and human tumor model].
Augmented antitumor activity was demonstrated in combination chemotherapy of Nedaplatin (NDP) or Cisplatin (CDDP) with 5-fluorouracil (5-FU) against murine lung carcinoma and human squamous carcinoma from head and neck. Either NDP or CDDP (1/4 to 1 maximum tolerated dose; MTD) was injected once and 5-FU (1/16 MTD) was injected daily for five days via tail vein to tumor-implanted mice. The sequential administration of either NDP or CDDP prior to 5-FU (NF or CF therapy) showed severe body weight loss followed by the toxic death of tumor-bearing mice at the MTD of NDP or CDDP. In contrast, the reverse sequence of the treatment, that is, 5-FU prior to NDP or CDDP (FN or FC therapy), resulted in the synergistically enhanced inhibition of tumor growth and the prolonged survival in comparison with NDP, CDDP or 5-FU monotherapy. The antitumor activities of the combinations of CDDP with 5-FU was less than those of the combination of NDP with 5-FU. Especially, at the MTD of NDP in FN therapy, long-term tumor-free survival was frequently observed. Thus, FN therapy was thought to be the most efficient regimen in combination of NDP with 5-FU as a clinical therapy.
Animals↗
[Two cases of cerebral aneurysm detected after recanalization of the middle cerebral artery].
Two cases of aneurysm incidentally detected after recanalization of middle cerebral artery (MCA) occlusion are reported. Patient 1 was a 62-year-old male with sudden onset of left hemiparesis. We performed emergent intravascular surgery. The initial cerebral angiography revealed occlusion at the M1 portion of the right MCA. After partial recanalization with a microcatheter, carotid angiography revealed a right M1-M2 junction aneurysm. Due to the risk of aneurysmal rupture, the thrombolytic procedure was stopped. Follow up angiography after 1 month revealed complete recanalization of the right MCA and a persistent aneurysm. Patient 2 was a 65-year-old male with left hemiparesis. The initial cerebral angiography revealed occlusion at the M1 portion of the right MCA. After 1 month follow-up cerebral angiography revealed spontaneous recanalization of the right MCA and an incidental aneurysm at the M1-M2 junction. Neck clipping of the aneurysm was performed. When using a microcatheter or microballoon catheter to treat arterial occlusion, surgeons should consider the possibility of a rupture of a hidden aneurysm.
Aged↗
Conditioned eyeblink response is impaired in mutant mice lacking NMDA receptor subunit NR2A.
NMDA receptor channels, heteromeric assemblies of subunits with diverse subtypes, play critical roles in various kinds of synaptic plasticity underlying learning and memory. To elucidate the roles of subunits NR2A and NR2C in motor learning, we investigated acquisition of the classically conditioned eyeblink response in a delayed-conditioning paradigm by gene knockout mice. Mutant mice lacking NR2C exhibited no significant defect; however, early acquisition of the task was impaired in mutant mice lacking NR2A or both NR2A and NR2C. Based on the distribution of these subunits in brain, these results indicate that acquisition of the conditioned response does not depend on NMDA receptors in the cerebellar cortex, but that its early acquisition involves the hippocampus and/or cerebellar deep nuclei.
Animals↗
Cationic amino acid transporter-2 mRNA induction by tumor necrosis factor-alpha in vascular endothelial cells.
Nitric oxide (NO) synthesis may be coupled to the activity of the cellular L-arginine transporter, namely the cationic amino acid transporter. The present study examined tumor necrosis factor (TNF)-alpha-induced alterations in the gene expression of the cationic amino acid transporter (CAT) and NO production in human umbilical vein endothelial cells. In quiescent endothelial cells, CAT-1 mRNA expression, determined by reverse transcription-polymerase chain reaction, was dominant to that of CAT-2. TNF-alpha (10 ng/ml for 1-24 h) induced a time-dependent increase in CAT-2 but not CAT-1 expression. Moreover, TNF-alpha (1-30 ng/ml) treatment for 6 h induced a concentration-dependent increase in CAT-2 mRNA expression. The upregulation of CAT-2 expression by TNF-alpha was associated with enhanced nitrite accumulation in the culture medium (70% increase compared with vehicle-treated cells at 24 h). Thus, induction of the cationic amino acid transporter may constitute one mechanism for the TNF-alpha-induced NO production in human umbilical vein endothelial cells.
Amino Acid Transport Systems, Basic↗
Nitric oxide mediates down regulation of lipoprotein lipase activity induced by tumor necrosis factor-alpha in brown adipocytes.
We previously reported that tumor necrosis factor-alpha (TNF-alpha)/cachectin suppresses lipoprotein lipase activity and its gene expression in brown adipocytes differentiated in culture. Recent evidence suggests that the effect of TNF-alpha over various cells is related to the enhanced production of nitric oxide (NO). The present study examined whether the suppressive effect of TNF-alpha on lipoprotein lipase activity is mediated by production of NO in the brown adipocytes. A reverse transcription-polymerase chain reaction (RT-PCR) assay revealed that TNF-alpha caused a concentration- and time-dependent expression of inducible NO synthase in brown adipocytes. Increasing concentrations of TNF-alpha (0.5-50 ng/ml) for 24 h resulted in a concentration-dependent decrease in lipoprotein lipase activity with reciprocal increase in nitrite production in the medium. The suppressive effect of TNF-alpha on lipoprotein lipase activity was significantly prevented by NO synthase inhibitors, NG-nitro-L-arginine methyl ester (L-NAME) and aminoguanidine, but not by D-NAME, an inactive isomer. Furthermore, 8-bromoguanosine 3',5'-cyclic monophosphate, cell permeant cGMP, suppressed lipoprotein lipase activity and 1 H-[1,2,4] oxadiazolo[4,3-a]quinoxalin-1-one, a selective inhibitor for soluble guanylate cyclase, restored the TNF-alpha-suppressed lipoprotein lipase activity. These results suggest that TNF-alpha stimulates brown adipocytes to express inducible NO synthase, followed by production of NO, which in turn mediates the suppressive effect of TNF-alpha on lipoprotein lipase activity. The effect of NO is mediated, at least partly, through production of cGMP.
Adipocytes↗
Purification and characterization of an Aspergillus oryzae-produced carboxylesterase that catalyzes O-deacetylation of a fully acetylated O-glucoside of N-phenylacetohydroxamic acid.
A carboxylesterase [2,3,4,6-tetra-O-acetyl-1-[(N-acetyl-N-phenylamino)oxy]-1-deoxy-beta-D-g lucopyranoside (GPA) O-deacetylase] from a culture product of Aspergillus oryzae (Taka diastase) was purified 8500-fold with a yield of 3%. The molecular mass of the purified enzyme was shown to be 35 +/- 1 kDa by SDS/PAGE. The enzyme shows a selective O-deacetylation activity of GPA to give the fully O-deacetylated glucoside. Among the substrates tested, the enzyme did not hydrolyze benzoyl and phenylacetyl esters and acetamides. In the hydrolysis of p-nitrophenyl esters, the acyl preference is acetyl > propionyl > butyryl, judging from the Vmax/Km values. A good correlation between log(Vmax/Km) and the Taft's Es constant of the alkyl group of the acyl moiety was obtained. The optimum pH was around 7.3 at 37 degrees C, and the enzyme was inhibited by mercuric chloride, p-chloromercuribenzoate and diisopropyl fluorophosphate. This enzyme should be useful for the selective removal of acetyl groups that serve to protect hydroxyl groups during carbohydrate synthesis.
Acetylation↗
Time-resolved imaging of protein kinase C activation during sea urchin egg fertilization.
To study protein kinase C (PKC) activation during sea urchin egg fertilization we used three different fluorescent probes specific for PKC, namely, fim-1, which recognizes the catalytic site of the enzyme, and BODIPY- and NBD-phorbol esters interacting with the PKC regulatory domain. We were able to follow PKC activation during the early steps of fertilization, the three different probes giving the same fluorescent pattern. Within 120 s following insemination, the fluorescent signal increased and clustered in the cortical zone of the cell. The process was Ca2+ dependent and was inhibited in the presence of staurosporine, a PKC inhibitor. According to our in vitro probe characterization, this signal increase is due to PKC activation. These findings were further confirmed by Western blot analysis. This initial phase was followed by a rapid decrease which might be attributed to PKC hydrolysis by Ca2(+)-dependent proteases. The kinetics and the site distribution of PKC activation appear in complete agreement with the putative functions previously suggested for PKC during fertilization.
Animals↗
Purification and characterization of guinea-pig liver microsomal deacetylase involved in the deacetylation of the O-glucoside of N-hydroxyacetanilide.
A microsomal deacetylase that catalyses the deacetylation of the O-glucoside of N-hydroxyacetanilide (GHA) was purified from guinea-pig liver. The activity was located exclusively in the microsomes and not detected in the cytosol. The purified GHA deacetylase was a trimeric protein with a molecular mass of 160+/-10 (S.D.) kDa composed of subunits of 53+/-2 kDa; its pI was 4.7. The N-terminal amino acid sequence of GHA deacetylase was similar to those reported for guinea-pig and rat liver microsomal carboxylesterases. The GHA deacetylase showed a comparable hydrolytic activity towards p-nitrophenyl acetate (PNPA), although the activities towards N-hydroxyacetanilide, acetanilide and some endogenous acylated compounds were very low or not detectable. The deacetylase activity towards GHA was inhibited by organophosphates but not by p-chloromercuribenzoate, suggesting that GHA deacetylase can be classified as a B-esterase. The enzyme exhibited a positive homotropic co-operativity towards GHA. The values of the Hill coefficient, the half-saturating concentration ([S]0.5) for GHA, and Vmax were 1.59+/-0.03, 5.51+/-0.07 mM and 32.5+/-1.4 micromol/min per mg respectively, at the optimum pH of 8.5. The bell-shaped pH dependence of the Vmax/[S]0.5 profile indicated pKa values attributed to histidine and lysine residues. The study of stoichiometric inhibition by di-isopropyl fluorophosphate and kinetic analysis with the Monod-Wyman-Changeux model suggests that GHA deacetylase has six substrate binding sites and three catalytically essential serine residues per enzyme molecule.
Acetylglucosamine↗
Facilitation of Ca2+ action potential frequency by a small G protein Rab3A in rat pituitary GH3 cells.
GH3 pituitary cells have high tendency to exhibit spontaneous Ca2+ action potentials and their frequency (Ca2+ APF) is increased by treatment with thyrotropin-releasing hormone (TRH). Although spontaneous Ca2+ firing was thought to be significant for the induction of oscillations in cytosolic Ca2+ concentration ([Ca2+]i), little attempt to elucidate the mechanism has been done so far. We demonstrate here that spontaneous Ca2+ APF in GH3 cells was increased 1.5-3 fold, comparable to that for TRH, by injection of guanosine 5'-0-3-thiotriphosphate (GTPgammaS), rab3A effector domain peptide, and phorbol-dibutyrate (PDBu), whereas guanosine 5'-O-(2-thiodiphosphate) (GDPbetaS), H-rab5 peptide, ras peptide, and 4 alpha-phorbol did not. The enhancement of Ca2+ firing by rab3A effector domain peptide was blocked by a protein kinase C (PKC) inhibitor, PKC(19-36). The present study suggests that the spontaneous Ca2+APF may be controlled by small G protein phosphorylated by PKC.
Action Potentials↗
Purification of a regulatory subunit of type II cAMP-dependent protein kinase from Drosophila heads.
The cytosolic extract from Drosophila heads was separated using anion-exchange column chromatography. Two types of cAMP-dependent protein kinase (PKA), type I and type II, were detected, and type II PKA was found to be a major isozyme. The regulatory subunit of type II PKA (RII) was purified, and only one isoform was observed. The purified protein had an apparent molecular mass of 51 kDa on SDS gel electrophoresis. Partial amino acid sequences of the protein were almost identical with the RII alpha subunit of human. Since PKA has been implicated to be especially important for learning and memory in Drosophila, the RII subunit may play an essential role in the regulation of neuronal activity in the brain of Drosophila, and possibly in human.
Affinity Labels↗
Cell cycle-dependent expression and spindle pole localization of a novel human protein kinase, Aik, related to Aurora of Drosophila and yeast Ipl1.
Mutations in Aurora of Drosophila and related Saccharomyces cerevisiae Ipl1 kinase are known to cause abnormal chromosome segregation. We have isolated a cDNA encoding a novel human protein kinase of 402 amino acids with a predicted molecular mass of 45.9 kDa, which shares high amino acid identities with the Aurora/Ipl1 protein kinase family; hence the cDNA is designated as aik (aurora/IPL1-related kinase). Amino acid sequence of C-terminal kinase domain of Aik shares 86, 86, 72, 59, and 49% identity with those of Xenopus XLP46APK and XLP46BPK, mouse STK-1, Aurora of Drosophila, and yeast Ipl1, respectively, whereas N-terminal domain of Aik shares high homology only with those of XLP46APK and XLP46BPK. Northern and Western blotting analyses revealed that Aik is expressed highly in testis and various proliferating cells including HeLa cells. In HeLa cells, the endogenous levels of aik mRNA and protein contents are tightly regulated during cell cycle progression. Both of these levels are low in G1/S, accumulate during G2/M, and reduce rapidly after mitosis. Its protein kinase activity is also enhanced at mitosis as inferred by exogenous casein phosphorylation. Immunofluorescence studies using a specific antibody have shown that Aik is localized to the spindle pole during mitosis, especially from prophase through anaphase. These results strongly suggest that Aik is a novel member of a protein kinase family possibly involved in a centrosome function(s) such as chromosome segregation or spindle formation.
Amino Acid Sequence↗
Isolation of a T-cell clone showing HLA-DRB1*0405-restricted cytotoxicity for hematopoietic cells in a patient with aplastic anemia.
The existence of T cells capable of inhibiting in vitro hematopoiesis has been shown in aplastic anemia (AA), although whether such inhibition is mediated by a specific immune reaction involving an HLA allele remained unknown. We isolated a CD4+ Vbeta21+ T-cell clone that was most dominant among Vbeta21+ T cells in the bone marrow (BM) of an AA patient whose HLA-DRB1 alleles included 1501 and 0405. The T-cell clone named NT4.2 lysed an autologous Epstein-Barr virus-transformed lymphoblastoid cell line (LCL) and phytohemagglutinin-stimulated lymphocytes (PHA-blasts) as well as allogeneic LCLs sharing HLA-DRB1*0405. Cytotoxicity against LCL cells and PHA-blasts by NT4.2 was blocked by anti-HLA-DR monoclonal antibody (MoAb) or anti-CD3 MoAb. NT4.2 also lysed autologous BM mononuclear cells enriched with CD34+ cells that had been cultured for one week in the presence of colony-stimulating factors as well as allogeneic CD34+ cells of a normal individual carrying HLA-DRB1*0405, cultured in the same way. Moreover, NT4.2 strongly inhibited colony formation by hematopoietic progenitor cells derived from cultured CD34+ cells sharing HLA-DRB1*0405. These results indicate that the AA patient has T cells capable of killing hematopoietic cells in an HLA-DRB1*0405-restricted manner and that such cytotoxic T cells may contribute to the pathogenesis of AA.
Aged↗
Orally active prostacyclin analogue in primary pulmonary hypertension.
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Administration, Oral↗
Quantitative analysis of the usage of human T cell receptor alpha and beta chain variable regions by reverse dot blot hybridization.
We previously developed an adaptor ligation-mediated PCR method to amplify the T cell receptor (TCR) cDNA pools. In the present study we applied reverse dot blot hybridization to PCR-amplified specimens for quantitative analysis of the usage of TCR alpha and beta chain variable (V) region. 44 VA sequence-specific oligonucleotide probes (SSOPs) and 38 VB SSOPs were synthesized corresponding to unique sequences of VA and VB subfamilies. Peripheral blood lymphocytes of ten healthy donors and five T cell clones established from bone marrow cells were examined for VA and VB usage using this method. The results were consistent with those obtained by a colony hybridization method and those by immunofluorescence staining using monoclonal antibodies to VA and VB. Thus, reverse dot blot hybridization for TCR V(alpha) and Vbeta is a new, easy and dependable technique useful for analysis of VA and VB usage by human T cells.
Base Sequence↗
Cytomedical therapy for IgG1 plasmacytosis in human interleukin-6 transgenic mice using hybridoma cells microencapsulated in alginate-poly(L)lysine-alginate membrane.
Cytomedical therapy for human interleukin-6 transgenic mice (hIL-6 Tgm) was implemented by the intraperitoneal injection of alginate-poly(L)lysine-alginate (APA) membranes microencapsulating SK2 hybridoma cells (APA-SK2 cells) which secrete anti-hIL-6 monoclonal antibodies (SK2 mAb). IgG1 plasmacytosis in the hIL-6 Tgm was suppressed by a single injection of APA-SK2 cells, and the survival time of these mice was remarkably prolonged. The viable cell number and the SK2 mAb-secretion of APA-SK2 cells increased for at least one month both under culture conditions and in allogeneic recipients (in vivo). Moreover, SK2 mAb which were secreted from APA-SK2 cells injected into allogeneic recipients was detected in serum at high concentrations; 3-5 mg/ml from day 14 to day 50 post-injection. In contrast, the injection of free SK2 cells had no therapeutic effect on hIL-6 Tgm. These results strongly suggest that APA membranes microencapsulating cells which were modified to secrete molecules useful for the treatment of a disorder were effective as an in vivo long-term delivery system of bioactive molecules, as 'cytomedicine'.
Alginates↗
Immunological studies of SK2 hybridoma cells microencapsulated with alginate-poly(L)lysine-alginate (APA) membrane following allogeneic transplantation.
Microencapsulation of living cells or tissues has been proposed to prevent their immune destruction following transplantation. In this study, we examined whether SK2 hybridoma cells microencapsulated in an alginate-poly(L)lysine-alginate (APA) membrane (APA-SK2 cells) were immunoisolated from the allogeneic host's immune system using a cytotoxicity test. The APA membrane inhibited the activation of the host's cellular immune response, but did not prevent the production of cytotoxic antibodies against entrapped SK2 cells following allogeneic transplantation. However, the APA-SK2 cells remained vital in SK2 cell-immunized mice as well as in intact mice. We considered that complement regulatory factors which were present on cell membrane and had species-specific restriction blocked the complement-mediated cell lysis on allogeneic transplantation, since APA-SK2 cells were destroyed by rabbit anti-SK2 cell antiserum. Our results demonstrated that APA membrane could inhibit cell-cell contact between entrapped cells and the host's lymphocytes, but could not completely protect the entrapped cells from xenogeneic humoral immunity.
Adoptive Transfer↗