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T Oguchi

Publications and source records attributed to T Oguchi.

At least 73 records · Page 4Linked to original sources
PubMed1995

High-resolution HLA-DQB1 typing by combination of group-specific amplification and restriction fragment length polymorphism.

A reliable method for high-resolution HLA-DQB1 typing using the combination of group-specific amplification and RFLP analysis is described. Group-specific amplification was carried out for the alleles of two groups using the two primer pairs under the same PCR conditions. One group contains DQ5 and DQ6 specificities and the other DQ2, DQ3, and DQ4 specificities. Computer analysis on cleavage patterns for 19 alleles of the DQB1 gene showed that the 11 alleles of the former group could be distinguished with five restriction enzymes and the eight alleles of the latter group could be distinguished with four enzymes. We could reduce the number of restriction endonucleases required compared with the number used in previous studies because we selected appropriate restriction enzymes which had at least one recognition site in almost all DQB1 alleles as a form of internal control. Moreover, DQB1*0602 and 0603, which were indistinguishable using the previously reported PCR-RFLP methods, could be distinguished by the present method. The results of typing of 100 samples from Japanese individuals by this method showed no discrepancy with the results obtained by serologic methods. The calculated allele frequencies showed good agreement with those reported at the 11th International Histocompatibility Workshop.

Base Sequence↗
PubMed1995

Comparative effects of halothane, enflurane, isoflurane and sevoflurane on function and metabolism in the ischaemic rat heart.

This study was designed to examined the effects of inhalation anaesthetics on function and metabolism in isolated ischaemic rat hearts. Four volatile anaesthetics in two different concentrations (1.0 to 1.5 MAC) were used before whole heart ischaemia was induced for 15 min followed by reperfusion for 30 min. The data were compared with a control group in which inhalation anaesthetics were not used. Before ischaemia, volatile anaesthetics depressed ventricular function. During reperfusion, ventricular function and coronary flow in both halothane groups were significantly lower than those in the control group. Myocardial ATP concentrations in the 1.0 MAC of enflurane and isoflurane groups were significantly higher than those in the control group. We conclude that halothane had more depressant effects than the other anaesthetics and that enflurane and isoflurane may enhance metabolic recovery in the ischaemic working rat heart.

Adenosine Triphosphate↗
PubMed1995

Zatebradine attenuates cyclic AMP-related positive chronotropic but not inotropic responses in isolated, perfused right atria of the dog.

1. Inhibition of I(f) or ICa by zatebradine has been reported in mammalian SA nodal cells. We thus investigated whether zatebradine differentially attenuates the positive chronotropic and inotropic responses to norepinephrine, isoproterenol, NKH 477 (an adenylyl cyclase activator), 3-isobutyl-1-methylxanthine (IBMX) and Bay k 8644 (a calcium channel agonist) in the isolated, blood-perfused dog atrium. 2. When zatebradine (0.03-1 mumol) decreased sinus rate from 104 +/- 4.5 to 73 +/- 4.9 beats/min dose-dependently, it selectively attenuated the positive chronotropic but not inotropic responses to norepinephrine in a dose-related manner. Zatebradine decreased the norepinephrine-induced tachycardia (by approximately 80% from the control) more effectively than the spontaneous sinus rate (by approximately 30% from the control). 3. Zatebradine similarly attenuated the positive chronotropic but not inotropic responses to isoproterenol, NKH 477 and IBMX. Fifty per cent inhibition doses of zatebradine (0.10-0.18 mumol) for the chronotropic responses to each substance were not significantly different. 4. On the other hand, zatebradine attenuated neither positive chronotropic nor inotropic responses to Bay k 8644. 5. We therefore suggest that zatebradine selectively attenuates the positive chronotropic but not inotropic responses to cyclic AMP-related substances due to inhibition of I(f) but not ICa in the dog heart.

1-Methyl-3-isobutylxanthine↗
PubMed1995

Multiplex ARMS-PCR-RFLP method for high-resolution typing of HLA-DRB1.

A reliable method for high-resolution HLA-DRB1 typing using the combination of group-specific amplification and RFLP analysis is described. Group-specific PCR amplification (multiplex ARMS-PCR) was carried out under the same conditions for all groups using seven different primer pairs divided into four groups: (1) DR1 and DR10; (2) DR2, DR7 and DR9; (3) DR3 DR5, DR6 and DR8, and (4) DR4. The subsequent polyacrylamide gel electrophoresis was used to determine the group(s) contained in each sample. DR1, DR2/7, DR3/5/6/8, DR4, DRB1*0901 and DRB1*1001 could be distinguished easily using this system. Computer analysis of the various restriction enzyme cleavage sites was carried out on 105 DRB1 allele sequences. It was shown that all DRB1 alleles, except for five allele pairs and some alleles possessing silent mutations, could be distinguished with commonly available restriction endonucleases. Computer analyses on the discrimination of the heterozygous and homozygous combinations were also carried out. Although some heterozygous combinations could no be distinguished with single digestion, double digestion using two restriction enzymes could distinguish most of such heterozygotes. The results of the typing of 100 Japanese individuals using this method showed good agreement with those obtained by other methods.

Alleles↗
PubMed1995

Purification and characterization of a cell-associated hemagglutinin of Vibrio parahaemolyticus.

We found a positive correlation between cell-associated mannose-sensitive hemagglutination and adherence of Vibrio parahaemolyticus to rabbit enterocytes by investigating 35 strains of V. parahaemolyticus for cell-associated hemagglutinin (cHA) and for the ability to adhere to the enterocytes. We purified a mannose-sensitive cHA from a Kanagawa phenomenon-positive clinical strain of V. parahaemolyticus that exhibited a high level of mannose-sensitive hemagglutination and strongly adhered to the enterocytes. The purified cHA is a heat-labile, tetrameric protein consisting of four identical subunits of approximately 26 kDa each. The adherence to rabbit enterocytes was inhibited in a dose-dependent manner by pretreatment of the bacterial cells with D-mannose and with the Fab fraction of immunoglobulin G against the purified cHA. Furthermore, pretreatment of the enterocytes with the purified cHA inhibited the adherence of V. parahaemolyticus. Immunogold electron microscopy revealed that the cHA is located on the bacterial cell surface and is not associated with pili. These results suggest that cHA is involved in the adherence mechanisms of V. parahaemolyticus to the enterocytes and that the receptors for cHA on the enterocyte appear to be a D-mannose-containing compound.

Animals↗
PubMed1995

[Determination of partial solubility parameters of lactoses and its application to solubility evaluation].

Partial solubility parameters of lactose packed into a glass column were calculated from adsorption energies of n-decane, acetonitrile and ethyl alcohol determined by gas-solid chromatography. Three kinds of crystalline lactoses, alpha-lactose monohydrate, anhydrous alpha-lactose (desiccated) prepared by desiccation with methyl alcohol, and anhydrous alpha-lactose (heated) prepared by heating, were used. It was characterized from the results that the partial solubility parameter, delta p, due to dipole interaction, of anhydrous forms had two-fold value than that of the hydrous form. In addition, it was suggested that the affinity of lactose for water vapor and the solubility of lactose for water were able to be evaluated using the three dimensional plot of partial solubility parameters and the interaction radius calculated from partial solubility parameters. It was shown that the appropriate information for the evaluation of physicochemical properties of active ingredients and excipients in the formulation study could be obtained from the data determined using partial solubility parameters.

Adsorption↗
PubMed1995

Effects of intravenous anesthetics on function and metabolism in the reperfused working rat heart.

We investigated the comparative effects of ketamine, flunitrazepam, diazepam and midazolam on function and metabolism in reperfused rat hearts. Seventy-two hearts were rapidly excised and perfused with buffer as a Neely's working model. Whole heart ischemia was induced for 15 min followed by reperfusion for 20 min. Four intravenous anesthetics in 2 different concentrations (10 and 50 times of therapeutic concentrations) were administered during reperfusion. The data were compared to a control group in which intravenous anesthetics were not used. At the end of reperfusion, myocardial metabolites were measured by liquid chromatography. Cardiac outputs in the both groups given lower and higher doses of ketamine and flunitrazepam and in the groups given the higher dose of diazepam and midazolam were significantly lower than that in the control group [at the end of reperfusion: control: 60.4; ketamine: 48.8 (lower) and 14.6 (higher); flunitrazepam: 50.2 (lower) and 50.6 (higher); diazepam: 62.6 (lower) and 42.5 (higher); midazolam: 59.5 (lower) and 51.2 (higher), ml/min]. The levels of ATP in all higher concentration anesthetic groups were significantly lower than those in the control group (control: 23.7, ketamine: 17.8, flunitrazepam: 17.8, diazepam: 17.7, midazolam: 17.7, mumol/g). These results suggest that ketamine and flunitrazepam moderately depress cardiac function more than diazepam and midazolam when they are given during reperfusion.

Anesthetics↗
PubMed1995

Selective inhibition by zatebradine and discrete parasympathetic stimulation of the positive chronotropic response to sympathetic stimulation in anesthetized dogs.

To investigate how to reduce the positive chronotropic response to sympathetic nerve activation selectively without affecting other cardiac actions, we studied the effects of zatebradine, an inhibitor of the hyperpolarization-activated current (I(f)), verapamil and parasympathetic nerve stimulation on the positive chronotropic, dromotropic and inotropic responses to sympathetic nerve stimulation in the autonomically decentralized heart of the open-chest anesthetized dog. Parasympathetic input was activated by stimulation of the cervical vagus (CV) or parasympathetic nerves to the sinoatrial (SA) nodal region (SAP). Zatebradine (0.1-3 mumol/kg i.v.) decreased the heart rate but not other cardiac responses to sympathetic nerve stimulation, i.e., a wave component of the right atrial pressure (RAP), the first derivative of the RAP (dRAP/dt), atrioventricular (AV) conduction time (AVCT), right ventricular pressure (RVP) and its first derivative (dRVP/dt). Zatebradine (1 mumol/kg) inhibited basal heart rate by 28% but inhibited the chronotropic response to sympathetic stimulation by 85%. Verapamil (0.06-0.6 mumol/kg i.v.) attenuated the increases in heart rate, RVP and dRVP/dt elicited by sympathetic stimulation but potentiated shortening of the AVCT from the prolonged basal AVCT. The SAP stimulation attenuated the heart rate and dRAP/dt responses to sympathetic stimulation without affecting other cardiac responses, whereas CV stimulation decreased the positive chronotropic and atrial and ventricular inotropic responses. Cervical vagus stimulation did not change the positive dromotropic response. These results demonstrate that in contrast to CV nerve activation or verapamil, zatebradine and SAP stimulation cause bradycardia but preserve the myocardial contractile force and AVCT in response to sympathetic nerve activation or sympathomimetic drugs in the heart in situ.

Animals↗
PubMed1995

Are negative chronotropic and inotropic responses to adenosine differentiated at the receptor or postreceptor levels in isolated dog hearts?

Inhibition by zatebradine, a specific bradycardic agent, of the negative inotropic but not chronotropic responses to adenosine has been briefly reported in the isolated, perfused dog heart. We therefore investigated whether subtypes of adenosine receptors or postreceptor transduction mechanisms differentiated the negative chronotropic and inotropic responses to adenosine in the isolated, blood-perfused atrial and ventricular preparations of the dog. Adenosine (1-3000 nmol), adenosine A1 receptor agonists, 2-chloroadenosine (CAD, 0.1-300 nmol) and N6-cyclohexyladenosine (CHA, 1-300 nmol) and a nonselective adenosine receptor agonist, 5'-N-ethyl-carboxamidoadenosine (NECA, 0.1-100 nmol), induced the negative chronotropic and inotropic responses. The potency order was NECA > CAD > adenosine > or = CHA. An adenosine A1 receptor antagonist, 1,3-dipropyl-8-cyclopentylxanthine (DPCPX, 10-300 nmol), dose-dependently inhibited the negative chronotropic and inotropic responses to adenosine, CAD and NECA in the isolated, perfused right atrium. DPCPX also blocked the negative inotropic responses to adenosine, CAD and NECA in the isolated left ventricle. However, an adenosine A2 receptor antagonist, 3,7-dimethyl-1-propargylxanthine (DMPX, 300 nmol), did not affect the negative cardiac responses to adenosine and NECA. Although the negative inotropic but not chronotropic responses to CAD and adenosine were dose-dependently inhibited by zatebradine, K+ channel inhibitors 4-aminopyridine and E-4031 did not modify the cardiac responses to adenosine and CAD. These results suggest that the negative cardiac responses to adenosine are mediated by adenosine A1 receptors and the negative chronotropic and inotropic responses to adenosine are differentiated at the postreceptor transduction level(s) in the dog heart.

2-Chloroadenosine↗
PubMed1995

[Aplastic anemia complicated with secondary hemochromatosis after allogenic bone marrow transplantation].

We report a case of aplastic anemia complicated with secondary hemochromatosis after allogenic bone marrow transplantation (BMT). A 29-year-old man was diagnosed as having aplastic anemia at the age of 8. At the age of 28, BMT was performed from his HLA-identical sister. Total volume of blood transfusion before BMT was about 28,000 ml, and in three months after BMT was 8,000 ml. The transplantation was successful, but one month after BMT, dry eyes, skin pigmentation and hepatomegaly appeared. Serum bile duct enzymes and ferritin also increased remarkably. Moreover after thirteen months, glucose tolerance impaired seriously. Abdominal computed tomography (CT) revealed atrophic pancreas and an increased CT density in the liver and the tail of the pancreas. A large amount of iron deposition were also found in liver and stomach biopsy specimens. We concluded that diabetes mellitus was due to secondary hemochtomatosis in the present case. There is a possibility that tissue damage due to iron deposits may have been accelerated through BMT in this patient with a history of many blood transfusions.

Adult↗
PubMed1995

[Anesthesia with transesophageal echocardiography for removal of pheochromocytoma].

A 45-year-old female was scheduled for left adrenalectomy because of a pheochromocytoma. Preoperative general condition was well controlled with alpha- and beta-blockers. Anesthesia was induced with thiamylal and vecuronium, and maintained with isoflurane (0.5-3%) and nitrous oxide in oxygen. Blood pressure was controlled with nicardipine and alpha-blocker during the manipulation of the tumor. After removal of the tumor, dopamine and norepinephrine were used. We used transesophageal echocardiography (TEE) to determine the fluid administration rate and doses of catecholamine. We could observe the wall motion and the mass of the heart, and see changes of the left ventricular enddiastolic volume, the cardiac output and the stroke volume. TEE monitoring seems to be very useful during the resection of pheochromocytoma.

Adrenal Gland Neoplasms↗
PubMed1994

Correlation between cell-associated mannose-sensitive hemagglutination by Vibrio parahaemolyticus and adherence to a human colonic cell line Caco-2.

Cell-associated hemagglutination (cHA) activity with human erythrocytes was examined for 468 clinical and 71 environmental strains of Vibrio parahaemolyticus. Approximately 95% of the strains tested were cHA positive irrespective of source or Kanagawa phenomenon. 75% of clinical strains showed relatively strong mannose-sensitive hemagglutination (MSHA), whereas 88% of the environmental strains showed relatively weak mannose-resistant hemagglutination (MRHA). Adherence of V. parahaemolyticus to Caco-2 cells was also determined. A clear positive correlation between cell-associated MSHA and adherence to Caco-2 cells was observed.

Bacterial Adhesion↗
PubMed1994

Fluorometric study of the molecular states of 2,5-diphenyloxazole in ground mixtures with gamma-cyclodextrin.

Molecular states of 2,5-diphenyloxazole (PPO) were investigated in ground mixtures with gamma-cyclodextrin (gamma-CD). Crystalline PPO gradually became amorphous upon grinding in the presence of gamma-CD. Solid-state fluorescence spectra of the ground mixtures showed that the fluorescence emission peak due to PPO crystals was reduced in intensity with an increasing duration of grinding. A new fluorescence peak attributed to PPO excimer appeared at a longer wave-length. Results of the time-resolved fluorescence study indicated that the cogrinding caused an increase in the portion of PPO excimer in the gamma-CD ground mixture. On the other hand, only a small portion of excimer was formed in ground mixtures with beta-CD, which has a smaller cavity than gamma-CD. These results suggest that cogrinding of PPO with gamma-CD caused two PPO molecules to be included in the gamma-CD cavity, contributing to excimer formation.

Cyclodextrins↗
PubMed1994

Effects of artificial blood (FC-43 emulsion) on myocardial energy metabolism in the rat heart-lung preparation.

We have assessed the effects of artificial blood (FC-43 emulsion) on myocardial energy metabolism in the rat heart-lung preparation. Animals were allocated to four groups (n = 8 each group) according to the ratio of perfusion blood and FC-43 as follows: group 1 = control, perfusion blood only; group 2 = 50% FC-43; group 3 = 75% FC-43; and group 4 = 100% FC-43. Hearts were perfused initially to a cardiac output of 30 ml min-1 and mean arterial pressure of 50 mm Hg. Thirty minutes after perfusion, the hearts were freeze-dried for 6 days. Myocardial high energy phosphates (ATP, ADP and AMP) were measured by high pressure liquid chromatography. Myocardial lactate and glycogen concentrations were measured by enzymatic methods. There were almost no significant differences in cardiac output, systolic pressure, right atrial pressure and heart rate among the groups. Oxygen contents of the perfusate in all FC-43 groups were significantly lower than those in the control group. Myocardial ATP concentrations in rats receiving 50%, 75% and 100% FC-43 were significantly lower than those in the control group. In addition, myocardial ADP and AMP concentrations in rats receiving 75% and 100% FC-43 were significantly higher than those in the control group. Although there is adequate oxygen-carrying capacity in FC-43 to maintain cardiac function during perfusion, the energy levels in the hearts perfused with FC-43 were lower than those in normal hearts.

Adenosine Diphosphate↗
PubMed1994

Parasympathetic control of right atrial pressure in anesthetized dogs.

We investigated whether the intracardiac parasympathetic ganglia for sinoatrial (SA) nodal pacemaker cells control the right atrial contractility selectively and totally in the autonomically decentralized heart of the open-chest anesthetized dog. Stimulation of the intracardiac parasympathetic nerves to the SA nodal area (SAP Stim) decreased the right atrial pressure (a wave pressure) and its first pressure derivative (dP/dt) as well as the atrial rate but did not change the atrioventricular (AV) conduction time. Stimulation of right and left cervical vagosympathetic complexes (CV Stim) decreased the a wave pressure, dP/dt, and atrial rate and prolonged the AV conduction time. When SAP and CV Stim decreased the atrial rate similarly, the decreases in a wave pressure and dP/dt in response to SAP Stim were less than those to CV Stim in unpaced and paced hearts. When treatment with hexamethonium bromide or tetrodotoxin into the SAP Stim locus abolished the decreases in atrial rate evoked by SAP and CV Stim, each treatment abolished the decrease in a wave pressure response to SAP Stim but only slightly attenuated the pressure response to CV Stim. These results demonstrate that right atrial pressure is modified by efferent parasympathetic neurons, which are located in a region that differs from that of efferent parasympathetic neurons controlling heart rate.

Animals↗
PubMed1993

Selective inhibition by E4080, a novel bradycardic agent, of positive chronotropic responses to norepinephrine in isolated dog hearts.

E4080, a novel bradycardic agent acts on various ionic currents including the hyperpolarization-activated inward current (I(f)), L-type Ca2+ current (ICa) and ATP-sensitive K+ (K+ATP) current in mammalian heart and vascular tissues. We thus investigated the chronotropic and inotropic effects of E4080 and its interaction with the positive cardiac responses to norepinephrine, 3-isobutyl-1-methyl-xanthine (IBMX) and Bay k 8644 in the isolated, blood-perfused dog right atria and left ventricles. E4080 (0.01-1 mumol) decreased the sinus rate and atrial and ventricular contractile forces in a dose-related manner. Glibenclamide (3 mumol) partly blocked the decrease in atrial force but not the decreases in sinus rate and ventricular force induced by E4080. Atropine (10 nmol) did not affect the negative cardiac responses to E4080. E4080 (0.01-1 mumol) inhibited the positive chronotropic responses to norepinephrine and IBMX dose dependently, but did not inhibit the positive inotropic ones in isolated atria. E4080 affected neither positive chronotropic nor inotropic responses to Bay k 8644. These results suggest that (1) the activation of K+ATP channels by E4080 is partly related to the decrease in atrial force but not the decreases in sinus rate and ventricular force, and (2) the selective inhibition of E4080 of the cyclic AMP-dependent positive chronotropic responses but not inotropic ones is probably due to the inhibition of I(f) rather than other properties, e.g., activation of K+ATP channels and inhibition of ICa in the dog heart.

1-Methyl-3-isobutylxanthine↗