Biomedical subjects

Y Hashimoto

Publications and source records attributed to Y Hashimoto.

At least 847 records · Page 47Linked to original sources

PubMed1994

[Effect of epinephrine added to spinal anesthesia with lidocaine and tetracaine].

The effect of epinephrine added to the solution of lidocaine and tetracaine for spinal anesthesia was investigated in patients undergoing elective surgery of lower extremities. Thirty patients received 3ml of 2% lidocaine and 0.4% tetracaine and 30 patients received the solution with 0.1 mg of epinephrine added. A lumbar puncture was performed at the L2-3 interspace, using a midline approach with a 25-gauge spinal needle. Mean highest level of pinprick analgesia was Th6.1 without epinephrine and Th4.4 with epinephrine, and mean time for regression to Th10 was 2.3 hours without epinephrine and 3.6 hours with epinephrine. Progression of analgesia level was significantly faster and prolongation of duration was significant greater after adding epinephrine. No severe complications were found in any patients. We concluded that adding 0.1 mg of epinephrine to 3 ml of 2% lidocaine and 0.4% tetracaine could produce clinically useful prolongation of spinal analgesia.

Adolescent↗

PubMed1994

Application of a new morphometry system based on SEM stereo-pairs to the study of intestinal mucosa of rodents.

A new morphometry system for submicroscopic three-dimensional structures was developed on the same principles as for the aerial survey using SEM stereo-pairs. This computer graphic system was applied to the analysis of the surface features of the intestinal mucosa. After removing the epithelial layer by prolonged osmication, core structures of the intestinal villi were exposed and 100 villi each from rat and mouse were measured. Average height, basal area and surface area of a single core of the rat were 188 microns, 20,200 microns2 and 93,500 microns2, respectively. Those of the mouse were 148 microns, 7,530 microns2 and 37,100 microns2, respectively. Surface amplifications by the rat and the mouse villi, after compensating for epithelial thickness, were calculated as 3.5 and 4.3, respectively; though amplifications based on the villous core were 4.6 and 4.9, respectively. These three-dimensional features of the intestinal mucosa were illustrated as submicroscopic maps by drawing their contour lines. It was demonstrated that the present morphometry system makes it possible to know not only the average features of a large sample, but also a variety of features of individual structures which were directly observed under SEM.

Animals↗

PubMed1994

Different interactions of Grb2/Ash molecule with the NGF and EGF receptors in rat pheochromocytoma PC12 cells.

We have previously shown that nerve growth factor (NGF) induces a rapid and relatively continuous activation of Ras in rat pheochromocytoma PC12 cells while epidermal growth factor (EGF) activates Ras transiently, and that tyrosine kinase activity of the NGF receptor is essential for the activation of Ras (Muroya et al., Oncogene, 7, 277-281, 1992). In order to explore the signaling mechanism from tyrosine kinase to Ras activation in more detail, interactions between two adaptor molecules, Shc and Grb2/Ash, which contain Src homology regions, and their interactions with the NGF and EGF receptors were examined. Both NGF and EGF induced rapid tyrosine phosphorylation of Shc and its association with both the receptors and with Grb2/Ash. When cells were stimulated with EGF at 4 degrees C, the activation of Ras proceeded slowly and MAP kinase activation was quite low. Under such restricted conditions, tyrosine-phosphorylated Shc formed a complex with Grb2/Ash, suggesting that the complex formation may be one of the immediate early responses. In contrast to Shc, Grb2/Ash bound to EGF receptor but did not form a stable complex with the NGF receptor. These results suggest that there may be an alternative pathway for the activation of Ras in PC12 cells.

Adaptor Proteins, Signal Transducing↗

PubMed1994

[Two case reports of recurrent mediastinitis with chronic mediastinal fistula successfully treated with muscle flap re-transposition].

We experienced two cases of recurrent poststernotomy mediastinitis with chronic mediastinal fistula. Both cases had already received muscle flaps for post operative mediastinitis. However, chronic mediastinal fistula appeared after nine months in the first case, and eleven months in the second case. We removed the infected tissue and the predgets, which were used on the ascending aorta. Then closed the wound by the muscle flap closure. The chronic fistula were closed, and the functional and cosmetic results were excellent.

Female↗

PubMed1994

[A case of paradoxical cerebral embolism through a patent foramen ovale diagnosed by necropsy].

A 62-year-old man was admitted to our hospital for disturbed consciousness and left-side motor sensory deficit. His blood pressure was 142/100 mmHg and an electrocardiogram was normal. CT of the brain revealed a low density area in the distribution of the right middle cerebral artery (MCA). Cerebral angiography demonstrated occlusion of the right internal carotid artery and an embolus. We diagnosed cerebral embolism, but we could not detect source of embolism. His condition deteriorated rapidly, and he died four days later. At necropsy, an elongated piece of thrombus 10 cm in length was lodged in a patent foramen ovale lying in each atrium. No other thrombus was seen in the heart, the myocardium and coronary arteries were normal. Both main pulmonary arteries contained thrombus. The lungs showed edema and congestion. There was no thrombus of both common iliac veins. The right internal carotid artery was occluded at its bifurcation by embolus, distal to which the cavernous segment was 7 cm filled with clot. We reported a rare paradoxical cerebral embolism through a patent foramen ovale diagnosed by necropsy. If no left-sided circulatory source can be demonstrated, the possibility of a paradoxical embolism should be considered.

Heart Septal Defects, Atrial↗

PubMed1994

[A gastric proton pump inhibitor as preanesthetic medication].

Effect of omeprazole, a gastric proton pump inhibitor, on gastric secretion during anesthesia and surgery was evaluated in 39 elective surgical patients ranged in age from 18 to 69 years. These patients were divided into two groups according to their age either of 40 years and under or over. The patients of both groups underwent orthopedic, ophthalmic, ENT, plastic, oral or non-abdominal surgery under neuroleptanesthesia, enflurane anesthesia or total intravenous anesthesia with droperidol, fentanyl and ketamine. They all were administered omeprazole 20 mg orally at 21:00 the night before surgery and again at 7:00 on the morning of surgery. The volume and acidity of gastric juice were measured at anesthetic induction and emergence from anesthesia. The volume and pH of the gastric juice in patients of 40 years and under in age averaged to 9.8 +/- 3.2 (mean +/- SE) ml, 2.45 +/- 0.56 at the anesthetic induction and 9.3 +/- 4.1 ml, 4.66 +/- 0.60 at the emergence from anesthesia respectively. The mean volume and pH of the gastric juice in patients over 40 years of age were 5.0 +/- 1.7 ml, 4.68 +/- 0.56 at the anesthetic induction and 9.9 +/- 2.4 ml, 5.76 +/- 0.36 at the emergence from anesthesia respectively. Significant decrease in the volume and acidity of gastric juice was observed in the patients of both groups except that the average of intragastric pH of the patients under 40 years of age was below 2.50 at the induction of anesthesia.(ABSTRACT TRUNCATED AT 250 WORDS)

Administration, Oral↗

PubMed1994

Cold agglutinin disease following allogeneic bone marrow transplantation.

We describe a case of cold agglutinin disease (CAD) following allogeneic bone marrow transplantation. This 36-year-old male developed CAD 3 weeks after allogeneic bone marrow transplantation for chronic myelogenous leukemia. Cyclosporin A and methotrexate had been administered to prevent graft-versus-host disease. Other agents administered included cytomegalovirus hyperimmune globulin and recombinant human G-CSF. Pericarditis preceded the development of CAD. The characterization of cold agglutinin (CA) was monoclonal IgM-kappa with anti-Pr antigen specificity, probably derived from the engrafted donor lymphocytes. The administration of prednisolone led to transient improvement. The CA titer decreased without further treatment 12 weeks after transplant.

Adult↗

PubMed1993

Ca2+ entry pathways activated by the tumor promoter thapsigargin in human platelets.

Thapsigargin-activated Ca2+ entry into platelets was examined in the presence of S-145, a thromboxane A2 receptor antagonist, to inhibit indirect effects by endogenously formed prostaglandin H2/thromboxane A2. With external Ca2+ present, 0.2 microM thapsigargin caused a prompt increase in intracellular Ca2+ concentration ([Ca2+]i) followed by a gradual increase. Pretreatment with 6 microM wortmannin, a specific inhibitor of myosin light chain kinase, partly inhibited the increase in [Ca2+]i. In Ca(2+)-free EGTA buffer, thapsigargin induced a smaller increase in [Ca2+]i, and subsequent addition of Ca2+ to the buffer caused a further prompt increase in [Ca2+]i, demonstrating external Ca2+ entry. Wortmannin only partly inhibited this entry of external Ca2+. The wortmannin-insensitive Ca2+ entry pathway remained open for more than 6 min in Ca(2+)-free buffer. On the other hand, when receptor agonists such as thrombin and U46619 were substituted for thapsigargin, activation of the wortmannin-insensitive Ca2+ entry was transient (Hashimoto et al., J. Biol. Chem (1992) 267, 17078-17081). In the presence of S-145 and wortmannin, thapsigargin stimulated phosphorylation of neither the 20-kDa myosin light chain nor the 47-kDa protein, a substrate of protein kinase C. These results suggest that thapsigargin induces external Ca2+ entry by two mechanisms: (1) a mechanism involving myosin light chain kinase; (2) a mechanism, not activated by receptor agonists, that is independent of the major protein kinases of platelets.

15-Hydroxy-11 alpha,9 alpha-(epoxymethano)prosta-5↗

PubMed1993

Purification of the antibacterial fragments of guinea-pig major basic protein.

In this study, we tried to purify the antibacterial fragments of guinea-pig major basic protein (MBP) using Staphylococcus aureus. The antibacterial activity of MBP was not affected by the pyridylethylation, suggesting that the disulfide bonds were not necessary for the antibacterial activity. When pyridylethylated-MBP was digested with alpha-chymotrypsin, the four potent antibacterial fragments (fragment V (Arg105-Tyr119), fragment IX (Thr1-Phe67), fragment X (Ile54-Leu97) and fragment XIII (Arg25-Phe67)) were isolated by reverse-phase high-performance liquid chromatography. Anti-MBP monoclonal antibody, BMK-13 neutralized the antibacterial activity of PE-MBP and fragments IX, X and XIII, but not the activity of fragment V, suggesting that Ile54-Phe67, the common amino-acid sequence of fragments IX, X and XIII, might be involved in the antibacterial activity of MBP. In fact, the synthetic peptide, Ile54-Phe67 exerted the antibacterial activity, and the activity was neutralized with BMK-13. The antibacterial activity of Ile54-Phe67 was lost by the modification with peptidylarginine deiminase which converted arginine residue to citrulline residue, suggesting that the arginine residues may be important for the antibacterial activity.

Amino Acid Sequence↗

PubMed1993

Purification and characterization of UDP-N-acetylgalactosamine GM3/GD3 N-acetylgalactosaminyltransferase from mouse liver.

A UDP-N-acetylgalactosamine: Sia alpha 2-3Gal beta 1-4Glc beta 1-/Sia alpha 2-8Sia alpha 2-3Gal beta 1-4Glc beta 1-1ceramide N-acetylgalactosaminyltransferase has been purified to apparent homogeneity from mouse liver. The purification procedure involved differential centrifugation for preparation of Golgi membranes, extraction of the enzyme with Triton X-100, and sequential chromatography on phosphocellulose, UDP-aldehyde adipic acid hydrazone agarose, UDP-hexanolamine-Sepharose, CM-Sepharose, and DEAE-Sepharose. At the phosphocellulose column chromatography step, the recovery of the enzyme activity was less than 25%, but it was enhanced up to 70% when the enzyme assay was performed in the presence of the flow-through fraction from the phosphocellulose column. With this assay, the enzyme activity was found to be quantitatively recovered during all the column chromatographies, the enzyme finally being purified 171,000-fold with a specific activity of 3.6 mumol/min/mg protein. The apparent molecular mass of the purified enzyme is 65,000 daltons. The enzyme exhibits a pH optimum of 7.5-7.9 and requires 2.5-10 mM Mn2+ for the maximal activity. The Km value for UDP-N-acetylgalactosamine is 7 microM. Among the glycolipids tested as acceptor substrates, NeuGc alpha 2-3Gal beta 1-4Glc beta 1-1ceramide, NeuAc alpha 2-3 Gal beta 1-4Glc beta 1-1ceramide, NeuGc alpha 2-8NeuGc alpha 2-3Gal beta 1-4Glc beta 1-1ceramide, and NeuAc alpha 2-8NeuAc alpha 2-3Gal beta 1-4Glc beta 1-1ceramide are good ones, the Km values for them being 160, 2,100, 27, and 350 microM, respectively, but sialyllactose, NeuAc alpha 2-3Gal beta 1-4Glc, is not. This suggests that the enzyme recognizes not only the oligosaccharide portion but also the ceramide of gangliosides.

Animals↗

PubMed1993

Subacute toxicity of piperonyl butoxide in ICR mice.

Piperonyl butoxide, alpha-[2-(2-butoxyethoxy)ethoxy]-4,5-methylenedioxy-2-propyltol uene, is a pesticide synergist. ICR mice of both sexes were maintained on diet containing 0, 0.1, 0.3 or 0.9% of piperonyl butoxide for 20 days. At the end of the experimental period, they were necropsied. Selected organs were weighed and serum chemistries were analyzed. In male and female mice of the 0.9% group, body weight, kidney and spleen weight were depressed in comparison to those of control group. Liver weight of the 0.3 and 0.9% group of both sexes were significantly higher than those of control group. Mice of the 0.9% group of both sexes had increased serum levels of cholesterol, total protein, gamma-glutamyl transpeptidase. Histological examination of livers from mice of the 0.9% group by light microscopy showed enlarged hepatocytes, anisonucleosis and single cell necrosis. The results indicated that subacute toxicity of piperonyl butoxide in ICR mice was directed primarily at liver.

Animals↗

PubMed1993

Lateral gap junction connections between retinal amacrine cells summating sustained responses.

Vertebrate retinal amacrine cells produce transient or sustained responses. Sustained depolarizing amacrine cells in the dace retina were identified by their intracellularly recorded responses to light flashes. The response amplitude produced a notable spatial summation which exceeded that of individual dendritic arbors. When sustained type amacrine cells were intracellularly injected with Lucifer Yellow and biocytin, there was extensive transfer of biocytin, but not Lucifer Yellow, to surrounding cells with similar cellular morphology. Ultrastructural analysis of the interconnections by electron microscopy revealed the presence of gap junctions at the contact area, which did not include conventional synapses. Present results demonstrate that sustained response amacrine cells make direct electrical connections between the cells of the same type and electrical coupling may contribute to extension of their receptive fields.

Animals↗

PubMed1993

K252a: a new blocker of the cell-cycle at G1 phase in a human hepatoma cell line.

The administration of 200 nM K252a to HuH7 suppressed the proliferation of the cells almost completely. The uptake of [3H]thymidine was inhibited, and flow cytometry revealed only one peak at 2C on day 3 after treatment with 100 nM K252a. The expression of proto-oncogene c-myc was not reduced. Despite the blockage at G1, both the size of the cells and the amount of cell protein had increased by 4 times by day 3 after treatment with K252a, while the cells secreted albumin and alpha-fetoprotein into the medium as usual. These results show that K252a can increase the cell size of HuH7 without losing its function by blocking the cell cycle at G1 phase.

Carbazoles↗

PubMed1993

Efficient immunostaining of tissue sections with chemically modified monoclonal antibody.

Monoclonal antibodies (mAbs) were modified with a photo-cross linker, sulfosuccinimidyl 2-(m-azido-o-nitrobenzamido)-ethyl-1,3'-dithiopropionate (SAND), and their efficacy in immunohistochemical staining of tissue sections was examined comparatively with that of unmodified mAbs. mAbs used were HBJ127 and SV2-61 gamma which recognized a proliferation-associated human gp125 cell surface antigen and a human c-erbB-2 protooncogene product, respectively. Both mAbs could stain relevant cancer tissue in frozen sections but not that in paraffin sections. Whereas SAND-modified mAbs intensely stained the cancer tissue in paraffin sections too, and the UV irradiation to SAND-modified mAb-treated tissue sections further increased the intensity of the staining. Scatchard plot analysis using 125I-labeled mAbs indicated that the augmentation of staining capacity by the SAND modification is due to the increase of the mAb amount capable of binding to the antigen.

Animals↗

PubMed1993

Enhancement by retinoid of hemin-induced differentiation of human leukemia K562 cell line.

The effect of retinoid on human leukemia K562 cell differentiation induced by hemin was examined. Retinoids (retinoic acid and synthetic retinoids [Am80 and Ch55]) dose-dependently enhanced hemin-induced erythroid differentiation of K562 cells, though these retinoids themselves did not induce the differentiation. Under optimal conditions, these retinoids caused a doubling of the population of hemin-induced differentiated cells. In addition, co-treatment of cells with hemin and retinoid led to longer maintenance of the differentiated state after the removal of hemin, which might imply acquisition of irreversibility of hemin-induced differentiation. These results suggest that the combination of retinoids with other differentiation inducers might be useful for leukemia therapy in cases where the leukemic cells are poorly responsive or unresponsive to retinoids, alone.

Cell Differentiation↗

PubMed1993

Oxygenated cholesterols as ligands for cytosolic-nuclear tumor promoter binding protein: yakkasteroids.

Several oxygenated cholesterols and their derivatives (yakkasteroids) were prepared as candidate ligands for cytosolic-nuclear tumor promoter binding protein (CN-TPBP). Among the compounds, a possible natural substance, 3 beta,5 alpha-dihydroxycholestan-6-one (yakkasterone), showed the highest binding affinity to CN-TPBP. It also showed high specificity for binding to CN-TPBP: it does not bind to protein kinase C. Investigation of the structure-activity relationships of yakkasteroids revealed that the structure of the side chain at the 20-position is important for the binding activity to CN-TPBP.

Binding, Competitive↗

PubMed1993

CD4+/CD8- thymocytes dominate the fetal thymus treated with a combination of anti-T cell receptor-beta and anti-CD4 antibodies.

Two major phenotypic changes characterize the development of a mature thymocyte from its CD4+/CD8+ (double positive or DP) precursor: the loss of expression of either CD4 or CD8 and the increase in the level of surface TCR. The specific surface interactions responsible for these changes are unknown, but studies using the fetal thymus as an experimental system have provided clues by identifying conditions that alter these maturational events. Development to the CD4+/CD8-/TCR-alpha beta high (single positive) phenotype is inhibited when thymocytes in fetal organ culture are exposed to antibodies directed against the CD4 molecule, the CD3 complex or the TCR-alpha/beta heterodimer. We show in this study, however, that treatment of fetal thymic lobes with a combination of anti-CD4 and anti-TCR-beta antibodies results in a marked increase in the proportion of mature CD4+/CD8-/TCR-alpha beta+ thymocytes and a decrease in the proportion of DP thymocytes. Although treatment of lobes with a combination of anti-CD4 and anti-CD3 epsilon antibodies also depletes cultures of DP thymocytes, the CD4+/CD8-/TCR+ population does not develop. Our results are consistent with the hypothesis that coengagement of CD4 and TCR biases development to the CD4 single positive phenotype and with observations that TCR engagement and CD3 engagement have different developmental consequences.

Animals↗

PubMed1993

Ventricular arrhythmias in Takayasu arteritis.

We studied the prevalence, severity and clinical significance of ventricular arrhythmias in 78 female patients with Takayasu arteritis by 24-h ambulatory electrocardiography monitoring. Fifty (64%) of 78 patients had no or less than 30 beats/h premature ventricular contractions (Group A). The remaining 28 (36%) patients exhibited frequent or complex premature ventricular contractions (Group B). The frequency of HLA Bw52 which is closely associated with this morbid condition, echocardiographic and thallium-201 stress myocardial scintigraphic findings were then compared between these two groups. The frequency of positive HLA Bw52 was not significantly different between these two groups. Echocardiographically determined left ventricular mass (309 +/- 94 vs. 166 +/- 64 g; P < 0.01), frequency of complicated aortic regurgitation (77% vs. 24%; P < 0.01) and abnormal thallium-201 scintigraphic findings (76% vs. 38%; P < 0.05) were found higher in Group B as compared with those in Group A. These data indicate that frequent or complex ventricular arrhythmias in patients with Takayasu arteritis were associated with the presence of left ventricular hypertrophy, aortic regurgitation and decreased coronary reserve.

Adult↗