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H Tsuchida

Publications and source records attributed to H Tsuchida.

At least 19 recordsLinked to original sources
PubMed1999

2'-Pyrene modified oligonucleotide provides a highly sensitive fluorescent probe of RNA.

Oligonucleotide 9mers containing 2'-O-(1-pyrenylmethyl)uridine [U(pyr)] at the center position were synthesized by using a protected U(pyr) phosphoramidite. The UV melting behaviors indicate that the pyrene-modified oligonucleotides can bind to both their complementary DNA and RNA in aqueous solution. When compared with the unmodified oligonucleotides, the pyrene-modified oligonucleotides showed higher affinity for DNA while exhibiting lower affinity for RNA. The pyrene-modified oligonucleotides in diluted solution exhibited fluorescence typical of pyrene monomer emission [lambdamax 378 (band I) and 391 nm (band III)]. When these oligomers bound to DNA, the fluorescence intensity ratio of band III/band I was increased. With this fluorescence change, a new broad emission (lambdamax 450 nm) due to exciplex between the pyrene and an adjacent nucleobase appeared. In contrast, addition of RNA to the pyrene oligonucleotides resulted in enhancement of the pyrene monomer emission with decrease in the fluorescence band ratio. The extent of the emission enhancement was found to be highly dependent on the nucleobase adjacent to the U(pyr) in the pyrene oligomers. The pyrene oligonucleotide containing dC at the 3'-site of the modification showed remarkable increase (approximately 250 times) in fluorescence (375 nm) upon binding to complementary RNA. The present findings would open the way to the design of a highly sensitive fluorescent probe of RNA.

Circular Dichroism↗
PubMed1999

Effect of ACE gene on diabetic nephropathy in NIDDM patients with insulin resistance.

We investigated the influence of the angiotensin-converting enzyme (ACE) gene on the onset and/or progression of diabetic nephropathy in 62 Japanese patients with non-insulin-dependent diabetes mellitus (NIDDM; type II diabetes). Because a number of factors are believed to be involved in the onset and/or progression of diabetic nephropathy, especially in patients with NIDDM, we selected the patients with well-matched risk factors, duration of disease, glycemic control, blood pressure, and others. All patients had normal renal function and none were receiving ACE inhibitors. Patients were divided into three groups according to albumin excretion rate (AER): group A, patients with an AER less than 15 microg/min (n = 29); group B, patients with an AER between 15 and 70 microg/min (n = 19); and group C, patients with an AER greater than 70 microg/min (n = 14). The glucose disposal rate was estimated using a euglycemic hyperinsulinemic clamp. We determined the mean glucose disposal rate in 132 patients with NIDDM (6.49 mg/kg/min). Patients with a glucose disposal rate less than the mean rate were considered to have a high degree of insulin resistance (n = 36). The presence of an insertion/deletion (I/D) polymorphism of the ACE gene was determined by the polymerase chain reaction method. Among patients with a high degree of insulin resistance, diabetic nephropathy was present in 2 of 11 patients with the II genotype of the ACE gene compared with 19 of 25 patients with the ID or DD genotype (P = 0.0024). The prevalence of diabetic nephropathy was greater in patients with both significant insulin resistance and the D allele (19 of 25) than in the remaining patients (14 of 37; odds ratio, 5.20). These results suggest that the ACE gene influences the onset and/or progression of diabetic nephropathy in patients with NIDDM with significant insulin resistance.

Diabetes Mellitus, Type 2↗
PubMed1999

The effect of propofol and thiamylal on hypertensive responses to a rapid increase in isoflurane concentration.

STUDY OBJECTIVE: To compare the effects of propofol and thiamylal on the hyperdynamic circulatory response caused by a rapid increase in isoflurane concentration. DESIGN: Prospective, randomized, double-blind study. SETTING: Operating rooms of a university hospital. PATIENTS: 30 ASA physical status I adult patients scheduled for elective surgery with general anesthesia. INTERVENTIONS: Patients were anesthetized with either propofol 2 mg/kg (propofol group, n = 15) or thiamylal 4 mg/kg (thiamylal group, n = 15). Two minutes after anesthesia induction, the inspired isoflurane concentration was rapidly increased from 0.5% to 5% and maintained for 5 minutes. MEASUREMENTS AND MAIN RESULTS: Mean arterial pressure significantly increased after the increase in isoflurane concentration in the thiamylal group, but it did not change in the propofol group. The isoflurane-induced increase in rate-pressure product was significantly greater in the thiamylal group than in the propofol group. CONCLUSION: Propofol induction of anesthesia more effectively attenuates the circulatory responses to a sudden increase in isoflurane concentration than does thiamylal.

Adult↗
PubMed1999

The direct effect of halothane on myocardial contraction in rat myocytes with poorly developed gap junctional intercellular communication.

BACKGROUND: The gap junction channel plays an important role in synchronous beating in the heart, and the reduction in the amount of gap junctional intercellular communication (GJIC) is thought to be the main arrhythmogenic factor in diseased heart. However, the effect of halothane on myocardial contraction in heart tissue with less GJIC is not well known. The purpose of the present study is to examine the direct effect of halothane on myocardium with poorly expressed GJIC. METHODS: Ventricular myocytes were obtained from neonatal rats by enzymatic digestion with collagenase and then cultured for 3 or 7 d. We have previously reported that the number of gap junctions at 3 d is approximately 10% of that at 7 d (1). The myocytes were stabilized in serum-free medium, and the spontaneous beating rate and amplitude were measured by a fiberoptic sensor. RESULTS: Heptanol (2 mM), an inhibitor of GJIC, abolished synchronized beating in myocytes cultured for 7 d. Halothane decreased the beating rate and amplitude in both groups of myocytes in a concentration-dependent manner (P < 0.05). Halothane at 1 and 2 MAC (adult rat MAC) decreased the beating rate more in myocytes cultured for 3 d than in myocytes cultured for 7 d (P < 0.05). Halothane reduced beating amplitude equally in both groups. Asynchronous contraction developed more frequently among myocytes cultured for 3 d than for those at 7 d. CONCLUSION: Halothane may block the GJIC channels, and when the number of these channels is reduced, exposure to halothane may cause asynchronous beating and decrease the beating rate. However, the halothane-induced decrease in amplitude is probably not due to blockade of GJIC because reducing the number of GJIC channels did not alter halothane's depressant effect.

Anesthetics, Inhalation↗
PubMed1999

High-level expression of maize phosphoenolpyruvate carboxylase in transgenic rice plants.

Using an Agrobacterium-mediated transformation system, we have introduced the intact gene of maize phosphoenolpyruvate carboxylase (PEPC), which catalyzes the initial fixation of atmospheric CO2 in C4 plants into the C3 crop rice. Most transgenic rice plants showed high-level expression of the maize gene; the activities of PEPC in leaves of some transgenic plants were two- to threefold higher than those in maize, and the enzyme accounted for up to 12% of the total leaf soluble protein. RNA gel blot and Southern blot analyses showed that the level of expression of the maize PEPC in transgenic rice plants correlated with the amount of transcript and the copy number of the inserted maize gene. Physiologically, the transgenic plants exhibited reduced O2 inhibition of photosynthesis and photosynthetic rates comparable to those of untransformed plants. The results demonstrate a successful strategy for installing the key biochemical component of the C4 pathway of photosynthesis in C3 plants.

Gene Dosage↗
PubMed1999

Anti-tumor polysaccharide from the mycelium of liquid-cultured Agaricus blazei mill.

Anti-tumor active polysaccharide against Sarcoma 180 was isolated by DEAE-Sepharose CL-6B and Sepharose 4B column chromatography from the hot-water soluble fraction of the mycelium of liquid-cultured Agaricus blazei mill. This polysaccharide did not react with antibodies of anti-tumor polysaccharides such as lentinan, gliforan, and FIII-2-b which is one of anti-tumor polysaccharides from Agaricus blazei. Moreover, the analyses of 13C-NMR and GC-MS suggested that this polysaccharide was preliminarily glucomannan with a main chain of beta-1,2-linked D-mannopyranosyl residues and beta-D-glucopyranosyl-3-O-beta-D-glucopyranosyl residues as a side chain. This polysaccharide was completely different from the anti-tumor polysaccharide from fruiting body of Agaricus blazei, beta-1,6-glucan.

Agaricus↗
PubMed1999

[Induction of anesthesia with propofol injected through a central venous catheter].

We compared propofol injected through a central venous catheter with that through a peripheral cannula from the standpoint of injection pain, induction time and hemodynamic changes. Thirty-nine patients about to receive abdominal surgery, who had central venous catheters inserted via the subclavian vein, were included in this study. General anesthesia was induced with a loading dose of propofol 1 mg.kg-1 followed by an infusion of 10 mg.kg-1.hr-1 into the central vein without carrier intravenous fluid (group A, n = 13), the peripheral vein without carrier intravenous fluid (group B, n = 13) or the peripheral vein with rapid infusion of acetated Ringer's solution (group C, n = 13). After endotracheal intubation, anesthesia was maintained with propofol 4 mg.kg-1.hr-1. The incidence of injection pain was 53% in group B and 76% in group C, whereas none of the patients in group A felt discomfort or pain during propofol injection. The mean induction time was significantly shorter in group A (43 +/- 12 sec) than group B (66 +/- 16 sec) or group C (57 +/- 11 sec). There were no differences between each group in hemodynamic changes during induction of anesthesia. Propofol injection via central venous catheter can avoid the injection pain and shorten the induction time.

Abdomen↗
PubMed1999

Halothane attenuates nitroglycerin-induced vasodilation and a decrease in intracellular Ca2+ in the rat thoracic aorta.

UNLABELLED: Although halothane inhibits endothelium-mediated vasorelaxation, the sites of inhibition remain controversial. Because the cytosolic concentration of Ca2+ ([Ca2+]i) has crucial roles for tension development, we examined the effects of halothane on nitroglycerin-induced vasorelaxation from the standpoint of [Ca2+]i. Isolated spiral strips of rat thoracic aorta without endothelium were suspended for isometric tension recordings in a physiologic salt solution. Muscle contraction was evoked with 10(-8) M norepinephrine, followed by endothelium-independent vasorelaxation with nitroglycerin 10(-7) and 10(-6) M. The effects of halothane 1.5% and 3% on nitroglycerin-induced vasorelaxation were evaluated along with the concomitant measurement of [Ca2+]i using fura-2-Ca2+ fluorescence. In other muscle strips, incremental doses of norepinephrine were administered during halothane exposure to induce contractions comparable to those without halothane. Nitroglycerin dose-dependently reduced norepinephrine-induced muscle contractions, but the decrease in [Ca2+]i reached a plateau at 10(-7) M, which indicates that nitroglycerin induced [Ca2+]i-dependent and [Ca2+]i-independent vasorelaxation. Both concentrations of halothane inhibited nitroglycerin-induced decreases in muscle tension and [Ca2+]i, not only when the same dose of norepinephrine was used for contraction during halothane exposure, but also at incremental doses of norepinephrine. In conclusion, halothane inhibits nitroglycerin-induced vasorelaxation partly by suppressing Ca2+ changes in the smooth muscle. IMPLICATIONS: We examined nitroglycerin-induced vasorelaxation in the rat thoracic aorta, along with the concomitant measurement of the cytosolic concentrations of Ca2+, and found that halothane attenuated endothelium-independent vasorelaxation by suppressing Ca2+ dynamics in the smooth muscle.

Anesthetics, Inhalation↗
PubMed1998

The usefulness of celite-activated thromboelastography for evaluation of fibrinolysis.

PURPOSE: Although thromboelastography is useful for measuring both coagulability and fibrinolysis, it takes about two hours to measure all parameters including fibrinolytic rate. The present study aimed to investigate the usefulness of celite-activated thromboelastography (TEGc) to evaluate fibrinolytic status in non-cardiac surgery. METHODS: Whole blood samples were obtained from 30 patients for non-cardiac surgery, and used for measurements of both native TEG (TEGn) and TEGc. The final concentration of 1% (w/v) celite was used for TEGc. RESULTS: Time for measurement of the fibrinolytic rate (FR) of TEGc in patients (56.7 +/- 4.0 min) was less than half that of FR of TEGn (123.3 +/- 15.6 min) (P < 0.05), suggesting a more rapid assessment of fibrinolytic status. A linear relationship was observed between FR values of TEGc and those of TEGn (r = 0.93, P < 0.0001), suggesting the usefulness of the fibrinolytic parameter of TEGc. CONCLUSION: TEGc is a useful technique for a more rapid assessment of fibrinolytic status.

Adult↗
PubMed1998

Ca2+ channel modulation alters halothane-induced depression of ventricular myocytes.

PURPOSE: This study examined the direct myocardial depressant effect of halothane and determined whether an L-type Ca2+ channel agonist and antagonists altered the myocardial depression induced by halothane in cultured rat ventricular myocytes. METHODS: Ventricular myocytes were obtained from neonatal rats by enzymatic digestion with collagenase and then cultured for 6 to 7 days. The myocytes were stabilized in a serum-free medium, and the spontaneous beating rate and amplitude were measured. To assess the halothane-induced conformational changes in L-type Ca2+ channel, receptor binding study was performed using a dihydropyridine derivative, [3H] PN 200-110, in cardiac membrane preparation. RESULTS: Halothane (1%, 2%, 3%, 4%) decreased the beating rate and amplitude in a concentration-dependent manner (P < 0.05). The myocardial depressant effects of halothane were potentiated by nifedipine or verapamil (P < 0.05). Bay K 8644, an L-type Ca2+ channel agonist, completely prevented the halothane-induced depression in amplitude (P < 0.05), but affected the beating rate less. Adding halothane (2%) decreased (P < 0.05) the maximum binding site density for [3H] PN 200-110 (from 198.6 +/- 23.7 fmol.mg-1 protein to 115.3 +/- 21.6 fmol.mg-1 protein) but did not affect binding affinity (from 0.461 +/- 0.077 nM to 0.307 +/- 0.055 nM). CONCLUSION: The reduction of Ca2+ current via sarcolemmal L-type Ca2+ channel, probably due to conformational changes in dihydropyridine binding sites, plays an important role in halothane-induced myocardial depression in living heart cells.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1998

Ascorbate peroxidase and catalase cooperate for protection against hydrogen peroxide generated in potato tubers during low-temperature storage.

We investigated the behavior of the antioxidant enzymes, superoxide dismutase (SOD), catalase (CAT), and ascorbate peroxidase (APx), in potato tubers during storage at low temperature. SOD activity increased temporarily within 3 weeks and was higher at 1 degree C than at 20 degrees C. APx activity also increased more at low (1 degree C) than at higher temperatures (5 and 20 degrees C). The contents of ascorbic acid (AsA), which is the substrate of APx, decreased immediately within 3 weeks and then gradually decreased until 15 weeks. The activity of CAT, the other enzyme which can scavenge hydrogen peroxide, decreased once in the first six weeks and thereafter increased to 15 weeks. Thus, the enhancement of the active oxygen-scavenging system that was induced by low temperature in potato tubers could result not only in a decrease of AsA but also in combined increases in APx and CAT activity whose manners were different.

Ascorbate Peroxidases↗
PubMed1998

Comparative myocardial depression of sevoflurane, isoflurane, and halothane in cultured neonatal rat ventricular myocytes.

UNLABELLED: In this study, we compared the direct myocardial depressant effects of sevoflurane, isoflurane, and halothane and determined whether an L-type Ca2+ channel agonist, Bay K 8644, could attenuate the myocardial depression induced by these anesthetics in cultured neonatal rat ventricular myocytes. Ventricular myocytes were obtained from neonatal rats by enzymatic digestion with collagenase and then cultured for 6-7 days. The myocytes were stabilized in serum-free medium, and the spontaneous beating rate and contractile amplitude were measured by using a fiberoptic sensor. Each anesthetic decreased the beating rate and amplitude in a concentration-dependent manner (1%-4% vol/vol) (P < 0.001), with halothane decreasing the beating rate and amplitude the most (P < 0.01). Isoflurane caused larger decreases in the beating rate than sevoflurane at 3% and 4% (P < 0.05). Potency for suppression of contractile amplitude was in the order of halothane > > isoflurane > sevoflurane. However, the myocardial depressant effects of the anesthetics were not different when their concentrations were corrected for minimum alveolar anesthetic concentration values. Bay K 8644 significantly prevented the anesthetic-depressed amplitude (P < 0.05). We conclude that sevoflurane, isoflurane, and halothane have direct myocardial depressant effects on cultured neonatal rat ventricular myocytes and that the reduction of sarcolemmal L-type Ca2+ channel current levels mediates the myocardial depression observed in these immature hearts. IMPLICATIONS: Sevoflurane, isoflurane, and halothane have a direct cardiodepressant effect on cardiac excitation-contraction coupling in the immature heart, which is mediated by an interaction with the L-type Ca2+ channel.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1998

Role of intracellular Ca2+ stores in the inhibitory effect of halothane on airway smooth muscle contraction.

BACKGROUND: Halothane directly inhibits contraction of airway smooth muscle, mainly by decreasing the intracellular concentration of free Ca2+ ([Ca2+]i). The role of intracellular Ca2+ stores, sarcoplasmic reticulum, is still unclear. We investigated the role of sarcoplasmic reticulum in the inhibitory effect of halothane on contraction of airway smooth muscle by measuring [Ca2+]i and intracellular concentration of inositol 1,4,5-triphosphate ([IP3]i), a second messenger for release of Ca2+ from sarcoplasmic reticulum. METHODS: [Ca2+]i was monitored by measuring the 500-nm light emission ratio (F340/F380) of a Ca2+ indicator fura-2 with isometric tension of canine tracheal smooth muscle strip. During Ca2+-free conditions, carbachol (10(-5) M) was introduced with pretreatment of halothane (0-3%). During Ca2+-free conditions, 20 mM caffeine, a Ca2+-induced Ca2+ release channel opener, was introduced with or without halothane. We measured [IP3]i during exposure to carbachol and halothane by radioimmunoassay technique. RESULTS: Pretreatment with halothane significantly diminished carbachol-induced increases in [Ca2+]i by 77% and muscle tension by 83% in a dose-dependent manner. Simultaneous administration of halothane significantly enhanced caffeine-induced transient increases in [Ca2+]i and muscle tension in a dose-dependent manner, by 97% and 69%, respectively. Pretreatment with halothane abolished these responses. Rapid increase in [IP3]i produced by carbachol was significantly inhibited by 32% by halothane in a dose-dependent manner. CONCLUSIONS: Halothane, during Ca2+-free conditions, inhibits transient contraction of airway smooth muscle induced by muscarinic receptor stimulation, mainly by attenuating the increase in [Ca2+]i. Depletion of Ca2+ from sarcoplasmic reticulum via Ca2+-induced Ca2+ release channels also may contribute to the attenuation of the increase in [Ca2+]i by halothane.

Anesthetics, Inhalation↗
PubMed1998

Effects of halothane and isoflurane on beta-adrenoceptor-mediated responses in the vascular smooth muscle of rat aorta.

BACKGROUND: Although previous studies have proposed that anesthetics may influence signal transduction systems, their effects on the beta-adrenoceptor-mediated system have not been fully characterized in vascular smooth muscle. The aim of this study was to determine how halothane and isoflurane affect beta-adrenoceptor-mediated vasodilation in rat aorta and what mechanisms were involved. METHODS: Isometric tension and the intracellular calcium ion concentration ([Ca2+]i) were measured concomitantly in rat aortic strips from which the endothelium was removed. Strips precontracted with norepinephrine were dilated with the beta-adrenoceptor agonist, isoproterenol; the adenylyl cyclase activator, forskolin; or the membrane-permeable dibutyryl cyclic adenosine monophosphate (cAMP) with or without halothane or isoflurane. The effects of the anesthetics on each vasodilator were compared with the control responses. Beta-adrenoceptor binding characteristics and affinity for agonists were determined with [125I]-iodocyanopindolol with and without halothane or isoflurane. Furthermore, concentrations of cAMP induced by either isoproterenol or forskolin were measured with or without the anesthetics using an enzyme immunoassay procedure. RESULTS: Halothane and isoflurane attenuated vasodilation and [Ca2+]i decreases induced by isoproterenol, whereas both anesthetics only slightly affected vasodilation and [Ca2+]i decreases induced by forskolin and dibutyryl cAMP. Halothane and isoflurane had no effect on beta-adrenoceptor binding characteristics and affinity for agonists. Three percent halothane or 4% isoflurane significantly reduced cAMP levels induced by isoproterenol but not by forskolin. CONCLUSIONS: Halothane and isoflurane, at clinically relevant concentrations, can interfere with beta-adrenoceptor-mediated responses in the rat aorta at the steps after the agonist-receptor binding but before the adenylyl cyclase activation.

Adrenergic beta-Agonists↗
PubMed1998

Polysaccharides from Agaricus blazei stimulate lymphocyte T-cell subsets in mice.

Subset analysis of splenic lymphocytes using flow cytometry showed that the percentages of Thy1.2-(pan T-cells), L3T4-(CD4, helper T-cells), and Lyt2-(CD8, cytotoxic T-cells) positive cell populations were significantly increased in mice orally administered a hot water-soluble fraction from Agaricus blazei as compared with mice treated only with saline. 13C-NMR data indicates that the main component in the active polysaccharide is the complex of alpha-1,6- and alpha-1,4-glucan, which had already been shown to have anti-tumor activity against Sarcoma 180. It seems that the polysaccharide from Agaricus blazei may be an effective prophylactic, protecting humans against cancer by stimulating lymphocytes such as cytotoxic T-cells.

Adjuvants, Immunologic↗
PubMed1998

[Changes in circulation and end-tidal sevoflurane concentration during infusion of sevoflurane into vaporizer].

We observed the changes in circulation and endtidal sevoflurane concentration during the infusion of the anesthetic into a vaporizer, and investigated some techniques to prevent these changes during general anesthesia. The patients were randomly divided into three groups: conventional, high concentration (conc.) and low flow groups. Inspiratory concentration of sevoflurane was kept at 1.0% and the duration of the pause in sevoflurane supply was 90 sec. The high conc. group was exposed to 2.0% sevoflurane for 60 sec. just before and after the pause, and the low flow group had a low fresh gas flow (0.5 l.min-1) during the pause. An increase in blood pressure and a tendency towards tachycardia were observed in the conventional group, and the circulation was kept constant best in the low flow group. The lowest concentrations of sevoflurane during the pause were 0.46, 0.46 and 0.93% in the conventional, high conc., and low flow groups, respectively, and exposure to high concentration of the anesthetic could not prevent the decrease. These results indicate that low flow anesthesia is a useful technique to prevent undesirable changes in circulation and anesthetic concentration.

Anesthesia, Epidural↗