Biomedical subjects

H Hashimoto

Publications and source records attributed to H Hashimoto.

At least 829 records · Page 46Linked to original sources

PubMed1991

Prostaglandin E1 receptor from mouse mastocytoma P-815 cells couples to 60 kDa GTP-binding protein.

The stable [3H]prostaglandin E1 (PGE1)-bound receptor, which couples to 60 kDa GTP-binding protein, from membranes of mouse mastocytoma P-815 cells has been purified and characterized. When the membranes were preincubated with [3H]PGE1 for 60 min at 37 degrees C, the dissociation of the ligand from the receptor was remarkably decreased, even in the presence of GTP gamma S. The stable [3H]PGE1-bound receptor complex was solubilized with 6% digitonin. The solubilized [3H]PGE1 receptor was eluted with [35S]GTP gamma S bindings activity from an Ultrogel AcA44 column. The fractions containing activities of both [3H]PGE1 and [35S]GTP gamma S bindings were further purified by column chromatographies on wheat germ agglutinin (WGA)-agarose and phenyl-Sepharose CL-4B. The partially purified [3H]PGE1-bound receptor was affinity-labeled with [14C]5'-p-fluorosulfonylbenzoylguanosine and a protein with a molecular mass of 60 kDa was detected. These results suggest that the ligand-bound PGE1 receptor of P-815 cells associates with a novel GTP-binding protein with a molecular mass of 60 kDa.

Adenylyl Cyclases↗

PubMed1991

[MR angiography of the forearm--visualization of the internal dialysis shunt].

Phase contrast MR angiography (MRA) of the forearm was performed in 10 healthy volunteers and 3 patients with chronic renal failure. In all volunteers, MRA demonstrated two arteries (radial artery and ulnar artery) and several cutaneous veins. In patients with chronic renal failure, internal dialysis shunts were clearly visualized and the stenoses of the shunts which were confirmed by later DSA were also well defined. It is concluded that MRA may be a valuable technic in the evaluation of internal dialysis shunts.

Arteriovenous Shunt, Surgical↗

PubMed1991

Characterization of five isomers of branched cyclomaltoheptaose (beta CD) having degree of polymerization (d.p.) = 9: Reinvestigation of three positional isomers of diglucosyl-beta CD.

It has been confirmed by methylation analyses and chemical syntheses that three isomers of branched cyclomaltoheptaose (beta CD) isolated from the mother liquors of a large-scale preparation of beta CD with Bacillus ohbensis cyclomaltodextrin glucanotransferase are 6(1),6(4)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (1), 6(1),6(3)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (2), and 6-O-(alpha-isomaltosyl)-cyclomaltoheptaose (4) instead of 6(1),6(2)-di-O-(alpha-D-glucopyranosyl)-cyclomaltoheptaose (3), which was erroneously characterized in an earlier paper. Compound 3 has been newly isolated from a glucosyl-beta CD mixture prepared by hydrolysis with glucoamylase of a maltosyl-beta CD mixture, synthesized from maltose and beta CD through the reverse action of pullulanase. Chromatographic behavior and spectral data (13C-n.m.r. and f.a.b.-m.s.) of these isomers of branched beta CD (1-4), as well as those of another isomer prepared by the reverse action of hydrolytic enzymes, 6-O-(alpha-maltosyl)-cyclomaltoheptaose (5), were compared.

Carbohydrate Sequence↗

PubMed1991

Increased methotrexate-induced DNA strand breaks and cytotoxicity following mutational loss of thymidine kinase.

The cytotoxicity and DNA lesions induced by methotrexate (MTX) were compared in wild-type, hypoxanthine-guanine phosphoribosyltransferase-deficient (HGPRT-) and thymidine-kinase-deficient (TK-) HL-60 cells. TK- and HGPRT- cells were approximately 10 and 3 times more sensitive to MTX than wild-type cells, respectively. Following incubation with 2 microM MTX for 16 hr, TK- cells showed a significantly higher number of DNA strand breaks. Concomitantly, DNA fragmentation at the nucleosomal linker region was detected more prominently in TK- cells. Although MTX tended to decrease TTP pools similarly in all 3 cells types, the initial TTP level in TK- cells was only about one-fifth of that found in the wild type. These results indicate that the thymidine salvage pathway has a pivotal role in mediating MTX-induced toxicity and DNA lesions.

Cell Line↗

PubMed1991

Differential regulation of thrombin- or ATP-induced mobilization of intracellular Ca2+ by prostacyclin receptor in mouse mastocytoma cells.

Thrombin induced an increase in [Ca2+]i in mouse mastocytoma P-815 cells. This increase was markedly reduced by prior exposure to pertussis toxin (PT) but not by removal of extracellular Ca2+, suggesting that thrombin stimulates phospholipase C via a PT-sensitive GTP-binding protein. ATP also induced an increase in [Ca2+]i. This increase was insensitive to PT but completely suppressed on removal of extracellular Ca2+, suggesting that ATP stimulates Ca2+ influx in a PT-insensitive manner. Iloprost, a stable prostacyclin analogue, increased the cellular cAMP level and dose-dependently inhibited the thrombin-induced increase in [Ca2+]i, whereas the ATP-induced increase in [Ca2+]i was markedly enhanced by iloprost. Cyclic AMP analogues, dibutyryl cAMP and 8-bromo cAMP, also inhibited the increase in [Ca2+]i induced by thrombin and promoted that by ATP, indicating that the inhibitory and stimulatory effects of iloprost are mediated by cAMP. These results suggest that the prostacyclin receptor differentially regulates two distinct Ca2+ mobilizing systems via cAMP in mastocytoma cells.

8-Bromo Cyclic Adenosine Monophosphate↗

PubMed1991

Cloning and characterization of a DNA fragment that complements the nfxB mutation in Pseudomonas aeruginosa PAO.

The 2.2-kilobase DNA fragment that can complement the nfxB mutation in Pseudomonas aeruginosa PAO was cloned from chromosomal DNA of P. aeruginosa PAO1. The nfxB mutants show an increase in resistance to quinolones and hypersusceptibility to beta-lactam and aminoglycoside antibiotics. In the mutants, a 54 kDa outer membrane protein newly appeared. The phenotype was restored to the wild-type by transformation with plasmid carrying the 2.2-kb DNA fragment.

Chromosomes, Bacterial↗

PubMed1991

Identification of mutations that occurred on the genome of Japanese encephalitis virus during the attenuation process.

The total nucleotide sequences of the genomes of two Japanese encephalitis virus (JEV) strains, the attenuated vaccine strain SA14-14-2 and its parental virulent strain SA14, were determined by using the molecular cloning technique. The sequence analysis revealed that both virion RNA molecules were 10,976 nucleotides long with 95 and 585 flanking bases at the 5' and 3' untranslated sequences, respectively. A single, long open reading frame spanning 10,296 nucleotides was observed to encode a polyprotein of 3432 amino acid residues. When these sequences were compared with each other, 57 nucleotide substitutions were found to be scattered all over the genome. Of these, 24 resulted in amino acid changes within viral proteins. Structural proteins C and E contain one and eight amino acid changes, respectively. Of the nonstructural proteins, NS1 contains three, NS2a two, NS2b two, NS3 four, NS4a one, NS4b one, and NS5 two amino acid substitutions. The 5'- and 3'-terminal untranslated regions contain one- and two- point mutations, respectively. These data and comparative studies with other JEV strain genomes provide a molecular basis for investigating attenuation mechanisms of JEV.

Amino Acid Sequence↗

PubMed1991

Clinical significance of IgG subclasses of Anti-Sm and U1 ribonucleoprotein antibodies in patients with systemic lupus erythematosus and mixed connective tissue disease.

IgG subclasses of anti-Sm and anti-U1 ribonucleoprotein (U1 RNP) antibodies were determined using a new clone of the anti-IgG2 antibody (HG2-56F). Although the predominance of IgG1 coincided with previous reports, IgG2 anti-Sm and U1 RNP antibodies were detected in numerous patients. IgG3 anti-Sm antibody significantly correlates with joint involvement and a high titer of anti-DNA antibody. On the other hand, IgG4 anti-U1 RNP antibody significantly correlated with esophageal dilation and muscular involvement. These results may suggest that some IgG subclasses are related to a specific clinical feature or manifestation.

Autoantibodies↗

PubMed1991

Preparation of Japanese encephalitis virus nonstructural protein NS1 obtained from culture fluid of JEV-infected Vero cells.

The Japanese encephalitis virus (JEV) nonstructural protein NS1 was released efficiently into culture fluid of JEV-infected Vero cells. The JEV NS1 protein in the infected culture fluid was found almost as a high-molecular-weight form, probably a dimer form of NS1, and was converted to a monomer by boiling. Large amounts of NS1 protein were accumulated in the infected culture fluid. The NS1 protein, separated from JE virions by centrifugation through sucrose layer, could be obtained in large quantities.

Animals↗

PubMed1991

Altered myocardial acetylcholine and norepinephrine concentrations in right ventricular hypertrophy and failure.

The progression of cardiac hypertrophy and failure is associated with marked changes in cardiac autonomic innervation, and there are sympathetic-parasympathetic interactions in the regulation of cardiac function. Although the indexes of sympathetic innervation have been found to be depressed with the development of heart failure, those of parasympathetic innervation have not yet been fully investigated. In order to better understand changes in markers of autonomic innervation associated with cardiac hypertrophy and failure, we measured the myocardial acetylcholine (ACh) store as a parasympathetic marker and the norepinephrine (NE) store as a sympathetic marker in pressure-overloaded right ventricular hypertrophy in rats. Two weeks after the injection of monocrotaline, significant right ventricular hypertrophy occurred. Three weeks after, severe right ventricular hypertrophy with no sign of heart failure occurred, and 4 weeks after, overt heart failure developed. In the right heart of monocrotaline rats, NE concentrations tended to increase at 1 week, returned to baseline at 2 weeks, decreased to one-half of the control values at 3 weeks, and then fell to 14% of the controls at 4 weeks. ACh concentrations in the right heart tended to increase at 1 week and exhibited a significant increase (136% and 129% of the controls in the right atrium and ventricle, respectively) at 2 weeks. As with NE, ACh concentrations in the right atrium and ventricle decreased to 76% and 54% of the controls at 3 weeks, and continued to decrease to 22% and 24% of the controls at 4 weeks after monocrotaline.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylcholine↗

PubMed1991

Functional T cell subpopulations responsible for hyposecretion of IL-2 in patients with systemic lupus erythematosus.

The ability of T cells to secrete IL-2 in patients with systemic lupus erythematosus (SLE) was investigated. In patients with SLE, impaired IL-2 production by peripheral blood lymphocytes stimulated with mitogens is well known. In this paper, we report that purified T cells stimulated with mitogens, in the presence of Epstein-Barr virus transformed B cells (B-LCL) as an accessory cell, however, could secrete a large quantity of IL-2 as much as normal T cells. In order to study this potential capacity of T cells to secrete IL-2 in patients with SLE, IL-2 secreting T cells were examined. To obtain these cells, T cells were divided into cluster forming cells and noncluster forming cells after short culture of T cells with accessory cells in the presence of Con A. Then the ability of IL-2 production in two kinds of separated T cells was examined. We found that 1) after short culture with B-LCL, the cluster forming T cells could secrete IL-2 when cultured again, but non-cluster forming T cells could not, even in the presence of B-LCL, 2) after short culture with macrophages, in normal donors and SLE patients, noncluster forming T cells were able to secrete a greater amount of IL-2 than cluster forming and undivided T cells when cultured with B-LCL.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗

PubMed1991

Klinefelter's syndrome associated with progressive systemic sclerosis: report of a case and review of the literature.

A case of Klinefelter's syndrome associated with progressive systemic sclerosis (PSS) is described. The patient had been infertile for 20 years after marriage and was diagnosed as PSS with Klinefelter's syndrome at the age of 43. In reviewing the literature, we observed that five cases with PSS within the range of 41 to 61 years of age, and seventeen cases with systemic lupus erythematosus (SLE), but only few cases with other connective tissue diseases were reported in association with Klinefelter's syndrome. Possible involvement of male hypogonadism in the pathogenesis of PSS was suggested.

Connective Tissue Diseases↗

PubMed1991

Quantitative estimation of infarct size by simultaneous dual radionuclide single photon emission computed tomography: comparison with peak serum creatine kinase activity.

To test the hypothesis that simultaneous dual energy single photon emission computed tomography (SPECT) with technetium-99m (99mTc) pyrophosphate and thallium-201 (201TI) can provide an accurate estimate of the size of myocardial infarction and to assess the correlation between infarct size and peak serum creatine kinase activity, 165 patients with acute myocardial infarction underwent SPECT 3.2 +/- 1.3 (SD) days after the onset of acute myocardial infarction. In the present study, the difference in the intensity of 99mTc-pyrophosphate accumulation was assumed to be attributable to difference in the volume of infarcted myocardium, and the infarct volume was corrected by the ratio of the myocardial activity to the osseous activity to quantify the intensity of 99mTc-pyrophosphate accumulation. The correlation of measured infarct volume with peak serum creatine kinase activity was significant (r = 0.60, p less than 0.01). There was also a significant linear correlation between the corrected infarct volume and peak serum creatine kinase activity (r = 0.71, p less than 0.01). Subgroup analysis showed a high correlation between corrected volume and peak creatine kinase activity in patients with anterior infarctions (r = 0.75, p less than 0.01) but a poor correlation in patients with inferior or posterior infarctions (r = 0.50, p less than 0.01). In both the early reperfusion and the no reperfusion groups, a good correlation was found between corrected infarct volume and peak serum creatine kinase activity (r = 0.76 and r = 0.76, respectively; p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS)

Clinical Enzyme Tests↗

PubMed1991

Preferential reactivity of autoantibodies in murine lupus NZB mice to neuraminidase-treated monosialogangliosides on B cells of mouse spleen.

When analyzed by flow cytometry, reactivity of IgM autoantibodies in sera from NZB mice to spleen B cells, but not to T cells, from BALB/c mice was remarkably increased after treatment of the cells with Vibrio cholerae neuraminidase. By TLC immunostaining with the antibodies, neither neutral nor acidic glycosphingolipids from both BALB/c and NZB mouse spleens were found to be reactive, but after neuraminidase treatment of the TLC plate, prior to the immunostaining, three components became reactive. All of the reactive glycosphingolipids were found to carry a single sialic acid residue and were at a concentration less than 1.3% of the total lipid-bound sialic acids. Their mobilities on TLC plate were close to those of IV3 NeuAcnLc4Cer, IV3 NeuAcII3 NeuAcGg4Cer, and IV3 NeuAcII3 NeuAc2Gg4Cer. In addition, the monosialogangliosides, which became reactive with the autoantibodies after neuraminidase treatment, were found to be predominantly distributed on B cells from BALB/c mice spleen, but not on T cells by TLC immunostaining. These studies demonstrate that the majority of IgM autoantibodies to spleen lymphocytes in sera from NZB mice might react preferentially to terminal sugar residues of three new glycosphingolipids masked by a single sialic acid on B cells, but not on T cells.

Animals↗

PubMed1991

Comparison of the effects of pirmenol and lidocaine on intraventricular conduction in canine myocardial infarction.

Effects of pirmenol hydrochloride and lidocaine hydrochloride on intraventricular conduction were examined in the infarcted heart of anesthetized dogs. The effects of the drugs on the excitation induced by ventricular stimulations were determined with coupling intervals between 150 and 1,000 ms. Effects of the drugs on the His bundle electrocardiograms were also examined. Pirmenol in doses of 1-5 mg/kg prolonged the conduction time in the infarcted zones over a wide range of coupling intervals. Pirmenol at 5 mg/kg blocked the delayed conduction at a short coupling interval in the infarcted zones. The effect of pirmenol on the conduction time in the normal zone was slight. Lidocaine in doses of 3 and 10 mg/kg prolonged the conduction time in the infarcted zone at a short coupling interval. Pirmenol did not significantly prolong PQ or AH interval. In conclusion, pirmenol selectively depressed the delayed conduction in the infarcted zone, which could result in a reentrant pathway. The effect of pirmenol on delayed conduction was dependent on the coupling interval and was quite different from that of lidocaine.

Animals↗

PubMed1991

Decreased 1,2-diacylglycerol levels in myopathic hamster hearts during the development of heart failure.

1,2-Diacylglycerol is believed to play an important role in cellular functions through protein kinase C activation, although its role in cardiac functions remains largely unexplored. We determined the level of 1,2-diacylglycerol and its fatty acid composition in heart tissues from Syrian hamsters with hereditary cardiomyopathy (BIO 14.6 strain) during the development of congestive heart failure from 90 days to 240 days of age. The myopathic hamsters had lower contents of triglyceride and of the major phospholipids, phosphatidylcholine, phosphatidylethanolamine and cardiolipin, in the myocardium when compared to normal hamsters, whereas there was no difference in the cholesterol content. No difference in the myocardial 1,2-diacylglycerol content was observed at 90 days of age. On the other hand, 1,2-diacylglycerol contents in myopathic hearts at 160 and 240 days of age were significantly lower by 21% and 52%, respectively, then in age-matched normal hamsters. The oldest hamsters (240-day-old) showed reduced 1,2-diacylglycerol levels in both groups despite an age-related increase in most lipids. The 1,2-diacylglycerol fatty acid composition profile was found to be different from that of other lipids, and there were several differences in the fatty acid composition of 1,2-diacylglycerol between the two groups at 240 days of age. These results indicate that decreased levels of 1,2-diacylglycerol occur concomitantly with congestive heart failure in the myopathic hamsters.

Animals↗

PubMed1991

TEI-9063, a stable and highly specific prostacyclin analogue for the prostacyclin receptor in mastocytoma P-815 cells.

The prostacyclin (PGI2) analogues, TEI-9063 and its methyl ester, TEI-1324, have been compared with another stable analogue, iloprost, with respect to binding to the PGI2 receptor, stimulation of adenylate cyclase activity and inhibition of thrombin-induced Ca2+ mobilization in mastocytoma P-815 cells. TEI-9063 displaced the [3H]iloprost binding to the membrane fraction, the IC50 value being 3 nM, but showed very low affinity for the PGE receptor. TEI-9063 dose dependently stimulated cAMP formation in the cells and GTP-dependent adenylate cyclase activity in the membrane fraction, the EC50 value being 50 and 10 nM, respectively. Furthermore, TEI-9063 prevented the thrombin-induced increase in the intracellular Ca2+ concentration, the IC50 value being 50 nM. These IC50 and EC50 values are lower than those obtained for iloprost. On the other hand, those of TEI-1324 were about two-orders higher. Although PGI2 lost its ability to stimulate cAMP formation by preincubation for 20 min at 37 degrees C, TEI-9063 completely retained its ability after 60-min preincubation. These results demonstrate that TEI-9063 is a stable and stronger agonist for the PGI2 receptor than iloprost, and that it prevents thrombin-induced Ca2+ mobilization through stimulation of the adenylate cyclase system in mastocytoma cells.

Adenylyl Cyclases↗

PubMed1991

Formation of GABOB from 2-hydroxyputrescine and its anticonvulsant effect.

To investigate the formation of gamma-amino-beta-hydroxybutyric acid from 2-hydroxyputrescine in mammalian organs, the radioactive diamine was synthesized and was injected into rats intraperitoneally or intraventricularly. After intraperitoneal injection, the radioactive amino acid was detected in various organs, but formation of the stereoisomer of the amino acid (gamma-amino-alpha-hydroxybutyric acid) was not demonstrated. Intraventricular injection of the radioactive diamine also resulted in the formation of gamma-amino-beta-hydroxybutyric acid in the rat brain. In vivo experiments using monoamine oxidase or diamine oxidase inhibitors suggested the participation of both enzymes in the formation of the amino acid from the diamine in rat organs other than the brain, where diamine oxidase appeared to play the major role. To investigate the anticonvulsant effect of 2-hydroxyputrescine, the threshold of pentylenetetrazol-induced generalized convulsions was measured in rats after the intraventricular injection of 2-hydroxyputrescine. Both R(-)- and S(+)-2-hydroxyputrescine had an anticonvulsant effect, with a greater elevation of the threshold being observed after injection of the R(-) form. Time course experiments suggested that this anticonvulsant effect depended on the formation of gamma-amino-beta-hydroxybutyric acid from 2-hydroxyputrescine in the rat brain. The anticonvulsant action of gamma-amino-beta-hydroxybutyric acid was also examined, and the stimulation of Cl- influx plus the inhibition of GABA uptake into brain membrane vesicles were indicated to be involved.

4-Aminobutyrate Transaminase↗