Biomedical subjects

T Tabuchi

Publications and source records attributed to T Tabuchi.

At least 19 recordsLinked to original sources

PubMed1996

Effects of angiotensin-converting enzyme inhibitor alacepril in patients with stable effort angina during chronic isosorbide dinitrate treatment.

Nitrate tolerance has been reported to be reversed by certain types of angiotensin-converting enzyme (ACE) inhibitors. We examined whether alacepril, a new long-acting oral ACE inhibitor, has beneficial effects against exercise-induced angina in patients with stable effort angina after substantial isosorbide dinitrate (ISDN) treatment. Thirteen men with stable effort angina were treated with oral ISDN (80 mg/d) for >3 weeks. After this period, efficacy of single oral administration of either alacepril (50 mg) or its placebo on exercise-induced angina and electrocardiographic changes was examined by treadmill exercise test in a double-blind crossover design. Alacepril significantly improved the exercise duration by 9.1% (p=0.03), the time to 1 mm ST-segment depression by 19% (p<0.01), and the maximal ST-segment depression by 33% (p=0.015) compared with placebo. Alacepril did not significantly alter the rate-pressure product, a marker of myocardial oxygen demand, during exercise test compared with placebo. Plasma renin activity was significantly increased (p<0.05) after administration of alacepril, indicating that alacepril significantly blocked ACE activity in our patients. In conclusion, a single oral administration of the ACE inhibitor alacepril (50mg) elicited beneficial effects against exercise-induced myocardial ischemia in patients with stable effort angina during chronic nitrate treatment. These effects may be mediated by increased coronary blood flow.

Aged↗

PubMed1996

Characteristics of slow conduction zone demonstrated during entrainment of idiopathic ventricular tachycardia of left ventricular origin.

Idiopathic ventricular tachycardia (VT) with the right bundle branch block pattern and left-axis deviation has been shown to be due to reentry, but the property of the slow conduction zone within the reentry circuit is little understood. In 7 patients (mean VT cycle length [CL]: 361 +/- 49 ms), rapid pacing from the right ventricular outflow tract was performed during VT while recording electrograms at the early activation site in the left ventricle and at the right ventricular apex; also, conduction times from the pacing site to these recording sits (St-A and St-B intervals, respectively) were measured. Both constant fusion (except for the last paced beat) and progressive fusion were seen in all patients, indicating VT entrainment. The left ventricular site was captured orthodromically with an St-A of 394 +/- 57 ms at the pacing CL of 351 +/- 47 ms during entrainment, while the right ventricular apex was captured directly with an St-B interval of 63 +/- 19 ms. The St-A interval was gradually prolonged with the shortening of the pacing CL, whereas the St-B interval remained unchanged. VT was interrupted in all patients at the pacing CL of 279 +/- 39 ms. The effects of intravenous lidocaine (1 mg/kg) and verapamil (1 mg) were examined in 5 and 7 patients, respectively. Neither drug terminated VT but the VT-CL was increased to 369 +/- 57 ms after lidocaine (p <0.05) and to 413 +/- 69 ms after verapamil (p <0.05) (p <0.05 vs after lidocaine). The St-A interval was significantly increased after lidocaine (p <0.05) and after verapamil (p <0.05), while the St-B interval remained unchanged. A significant correlation between changes in St-A interval and VT-CL after verapamil was noted (p <0.001). In conclusion, the slow conduction zone of this VT shows tachycardia-dependent conduction delay, and the mechanism of this slow conduction involves mainly calcium channel-dependent conduction and partly depressed sodium channel-dependent conduction.

Adolescent↗

PubMed1996

Impairment of coronary blood flow regulation by endothelium-derived nitric oxide in dogs with alloxan-induced diabetes.

Diabetes mellitus is a major cause of ischemic coronary artery disease. Endothelial dysfunction is implicated in the pathogenesis of diabetic vascular disease. To examine coronary blood flow (CBF) regulation with endothelium-derived nitric oxide (EDNO) in the diabetic state, we compared the effects of both acetylcholine (ACh) and adenosine (Ado) on left circumflex coronary artery (LCX) blood flow in 12 vehicle-treated and 21 dogs made diabetic with alloxan anesthetized with pentobarbital. All dogs were pretreated with aspirin to inhibit endogenous prostaglandins. None of the hemodynamic parameters were significantly different in the two groups. The percent change in coronary vascular resistance (CVR) after ACh (100 ng/kg) infusion was significantly attenuated in diabetic dogs (-56.5 +/- 1.4%) as compared with vehicle-treated dogs (-64.5 +/- 1.2%) (p < 0.01), whereas the effect of Ado (1 microgram/kg) was not different between the two groups (-71.1 +/- 1.5% in vehicle, -67.0 +/- 1.3% in diabetes). After infusion of incremental doses of NG-nitro-L-arginine methyl ester (L-NAME) 10(-5)-10(-3)M, the effect of ACh was progressively inhibited in both groups and was different no longer between the two groups after the maximal dose. L-Arginine (L-ARG), but not D-ARG, significantly restored the effect of ACh in diabetic dogs but did not affect vehicle-treated dogs. The effect of Ado did not change after L- and D-ARG administration. Cu, Zn-superoxide dismutase (Cu, Zn-SOD) had no effect on any of the effects of ACh and Ado in diabetic dogs. Regulation of CBF with EDNO is impaired in dogs with alloxan-induced diabetes, and this impairment is partially restored by L-ARG.

Acetylcholine↗

PubMed1996

Role of adenosine in regulation of coronary flow in dogs with inhibited synthesis of endothelium-derived nitric oxide.

Endothelium-derived nitric oxide (NO) regulates coronary blood flow, but it is unclear how NO synthesis inhibition affects myocardial metabolism. In pentobarbital sodium-anesthetized dogs, myocardial oxygen metabolism, adenosine release, lactate extraction rate (LER), and systolic ventricular wall thickening (SWT) at baseline and during atrial pacing were estimated before and after intracoronary NG-nitro-L-arginine methyl ester (L-NAME) infusion. Coronary blood flow and PO2 in the anterior interventricular vein at baseline were both significantly decreased by L-NAME (3 x 10(-4) M in the coronary blood). Coronary flow was increased during pacing, which was not affected by L-NAME. Myocardial adenosine release remained unchanged during pacing before L-NAME, but it was significantly increased after L-NAME infusion. Neither LER nor SWT changed during pacing performed before and after L-NAME. The experiment was also performed in dogs pretreated with 8-phenyltheophyl-line. After L-NAME, pacing-induced increase in coronary flow was suppressed, and both LER and SWT were significantly decreased during pacing. In conclusion, when NO synthesis is inhibited, adenosine release is increased in response to the increase in myocardial oxygen demand. With this compensatory adenosine release, coronary flow is increased and ventricular function is unaffected.

Adenosine↗

PubMed1996

Enhancement of myocardial reactive hyperemia with manganese-superoxide dismutase: role of endothelium-derived nitric oxide.

OBJECTIVE: To test the hypothesis that superoxide radicals generated during myocardial ischemia and reperfusion influence reactive hyperemia (RH) by reacting with endothelium-derived nitric oxide (EDNO), we examined the effect of manganese (Mn)-superoxide dismutase (SOD) on RH in anesthetized dogs. METHODS: Twelve dogs were pretreated with 8-phenyltheophylline (8PT) to block adenosine's effect. Five dogs were pretreated with 8PT and NG-nitro-L-arginine methyl ester (L-NAME) to block adenosine's and EDNO's effects. Following occlusion of the left circumflex artery (LCX) for 10 and 60 s, RH was observed before and after Mn-SOD. In another group of 6 dogs pretreated with 8PT, RH following 60-s LCX occlusion was observed before and after Mn-SOD and catalase. For comparison with the effect of Mn-SOD, that of copper, zinc (Cu,Zn)-SOD was also examined in another group of 5 dogs. RESULTS: In the dogs pretreated with 8PT, Mn-SOD significantly increased excess flow and repayment of flow debt during RH after 60-s LCX occlusion but did not affect RH after 10-s LCX occlusion. Mn-SOD-induced augmentation of RH following 60-s LCX occlusion was not affected by catalase, while it was completely abolished by L-NAME. In contrast to Mn-SOD, Cu,Zn-SOD showed no effect on RH following 60-s LCX occlusion in the dogs pretreated with 8PT. CONCLUSIONS: Superoxide radicals generated during ischemia for 60 s and reperfusion attenuates myocardial RH through inactivation of EDNO. Mn-SOD shows more beneficial effects on myocardial RH than Cu,Zn-SOD.

Adenosine↗

PubMed1995

Linear ablation of the isthmus between the inferior vena cava and tricuspid annulus for the treatment of atrial flutter. A study in the canine atrial flutter model.

BACKGROUND: The isthmus between the inferior vena cava and the tricuspid annulus has been shown to be involved in the reentry circuit of common atrial flutter. The effects of radio-frequency catheter ablation of this isthmus were examined in the canine model of atrial flutter due to reentry around the tricuspid annulus. METHODS AND RESULTS: A model of atrial flutter was prepared in 11 of 14 dogs by creating intercaval and connected transverse lesions (Y-shaped lesion). Bipolar electrodes were attached at 24 atrial sites, and computer-assisted mapping was performed. Stable atrial flutter with a cycle length of 133 +/- 11 ms was repeatedly induced by rapid atrial pacing in all dogs, and atrial mapping revealed reentry around the tricuspid annulus including the isthmus. In 6 dogs, the isthmus was ligated during atrial flutter (mechanical ablation). In the other 5 dogs, a 7F large-tip electrode catheter was placed at the isthmus under a fluoroscopic control. Radiofrequency energy (25 W for 30 s) was delivered to three sequential sites from the tricuspid annulus to the inferior vena cava to ablate the isthmus linearly. Atrial flutter was terminated in all dogs after mechanical and radio-frequency ablation of the isthmus and was not induced again. Atrial pacing from the posterior left atrium during sinus rhythm demonstrated intra-atrial conduction block at the isthmus after ablation. Pathological examination of the isthmus showed transmural myocardial damage. CONCLUSIONS: Linear radiofrequency ablation of the isthmus can induce intra-atrial conduction block and is effective as a curative therapy for atrial flutter when the reentry circuit involves the isthmus.

Animals↗

PubMed1995

Diverticular disease of the colon at a regional general hospital in Japan.

PURPOSE: X-ray film registry records were reviewed to better understand the changing nature of diverticular disease (DD) of the colon in Japan. RESULTS: Among 6,849 patients undergoing barium enema examination during a eight-year period from 1985 to 1992, this condition was found in 1,074 patients (15.7 percent), including 702 males (65.4 percent) and 372 females (34.6 percent). During this eight-year period there was an increase in frequency from 10.7 percent in 1985 to 17.8 percent in 1992. The proportion of patients with right-sided, bilateral, and left-sided DD was 69.2 percent, 17.5 percent, and 13.3 percent, respectively. The right-sided DD was more common in the younger age group and was predominant in male patients, whereas the left-sided DD increased with age, especially in female patients. Of the 1,074 patients, 11 (1.0 percent) underwent surgery in the same period. Regarding the right-sided DD, only 2 of 743 patients received surgery (0.3 percent). On the other hand, of the 143 patients with left-sided DD, 9 patients (6.3 percent) received some form of surgery. CONCLUSION: Right-sided diverticular disease of the colon is still common in Japan. It does not appear that this tendency will change in the future. Nearly all patients diagnosed as having diverticula had either no symptoms or only mild symptoms, and only about 1 percent required surgery. Right-sided diverticular disease of the colon seems to have had no serious clinical problems compared with left-sided DD.

Adolescent↗

PubMed1995

Ventricular gradient variability. New ECG method for detection of ischemic heart disease.

The usefulness of ventricular gradient variability for detecting the presence of ischemic heart disease was evaluated in 38 patients with coronary artery disease (group 1), 21 patients with chest pain and no coronary artery disease (group 2), and 33 healthy control subjects. The ventricular gradient of each consecutive heartbeat at rest over a 22-second interval was calculated using a microcomputer. The SD and coefficient of variation for azimuth, elevation, and magnitude were used as indices of ventricular gradient variability. The SD and coefficient of variation of both the magnitude and elevation of ventricular gradient in group 1 were significantly greater than those of the other two groups (P < .01, respectively). When the normal upper limit was defined as 2SD above the mean value in the control group, a comparison between the findings for group 1 and group 2 revealed that the coefficient of variation of magnitude of the ventricular gradient was the most sensitive (82%) and specific (91%) index for coronary artery disease (chi-square test, P < .001). This study suggests that the variability in the magnitude of the ventricular gradient is a reliable index of ischemic heart disease.

Electrocardiography↗

PubMed1995

Short-term topical therapy of experimental tinea pedis in guinea pigs with lanoconazole, a new imidazole antimycotic agent.

The therapeutic efficacy of short-term treatment with a 1% cream of lanoconazole, a new imidazole antimycotic agent, in comparison with that of a 1% cream of terbinafine was evaluated in the guinea pig model of tinea pedis. Each agent was topically applied once a day for 3 or 7 consecutive days, starting on day 10 postinfection, and a culture study was conducted on day 5 after the last treatment with each agent. The 1% cream of lanoconazole was as highly effective as the 1% cream of terbinafine in terms of eradicating the fungi from the infected feet.

Administration, Topical↗

PubMed1995

Radiofrequency catheter ablation of accessory atrioventricular pathway in Wolff-Parkinson-White syndrome.

Eighty patients with manifest or concealed Wolff-Parkinson-White (WPW) syndrome underwent catheter ablation of 86 accessory pathways (AP) using radiofrequency current. There are 65 AP located on the left side and 21 on the right side of the heart. The atrioventricular reciprocating tachycardia was previously documented in 77 patients and atrial fibrillation with a rapid ventricular response in 21 patients. Ablation was attempted via a catheter positioned at the atrial aspect of the tricuspid annulus in patients with a right-sided AP and via a catheter positioned in the left ventricle directly below the mitral annulus in patients with a left-sided AP. AP conduction was permanently abolished in 82 of the 86 pathways (95%). The number of radiofrequency current applications for these 82 successfully ablated AP was 7.6 +/- 0.9. Of the 65 left-sided and 21 right-sided AP, 62 (95%) and 20 AP (95%) were successfully ablated, respectively. The current application to the right-sided AP was 16.7 +/- 2.2, which was greater than that to the left-sided one (4.7 +/- 0.6, p < 0.001). No serious complication was observed in any case. Catheter ablation of AP using radiofrequency current is an effective and safe therapeutic modality for patients with symptomatic WPW syndrome.

Adolescent↗

PubMed1995

[Therapeutic efficacy of lanoconazole ointment in guinea pig model of tinea corporis, a comparative study with ointment and cream preparations].

The therapeutic efficacy of ointment and cream preparations of lanoconazole in a guinea pig model of tinea corporis was compared on the basis of degrees of improvement in local symptoms and negative culture rates. When infected animals were treated once daily with 0.25%, 0.5% and 1% lanoconazole ointments, significant improvement of the symptoms and mycological curative effects were observed as compared to those of non-treated control and vehicle-treated control groups of animals. Particularly, in animals treated with 0.5 or 1% lanoconazole ointment, no fungus was recovered from any infected loci. Comparing these results with those obtained with comparable concentrations of lanoconazole cream, no significant difference was found. These studies, therefore, suggested that ointment and cream preparations of lanoconazole on topical application would show basically equivalent therapeutic efficacy in the tinea corporis model.

Animals↗

PubMed1994

Vasodilator effect of carboxy-2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl in the coronary circulation: in vivo and in vitro studies.

2-Phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide (PTIO) derivatives, new radical forms of nitric oxide (NO) antagonists, are reported to react with NO and generate NO2 and 2-phenyl-4,4,5,5-tetramethylimidazoline-1-oxyl (PTI) derivatives. We found that carboxy-PTI, a water-soluble derivative of PTI, showed a potent vasodilator effect in the canine coronary artery system. In anesthetized dogs, intracoronary infusion of carboxy-PTI significantly increased the coronary flow in a dose-dependent manner without altering systemic hemodynamic variables. This coronary flow increasing effect of carboxy-PTI was not influenced by pretreatment with either NG-nitro-L-arginine methyl ester or 8-phenyltheophylline or autonomic blockade. However, the flow increasing effect of carboxy-PTI was abolished by reducing carboxy-PTI with ascorbic acid to a non-radical form of carboxy-PTI, indicating that carboxy-PTI shows its effect only in a radical form. In isolated canine coronary arterial rings, carboxy-PTI caused endothelium-independent relaxation. This relaxation response was significantly attenuated by pretreatment with methylene blue, an inhibitor of soluble guanylate cyclase. Thus, carboxy-PTI has an endothelium-independent coronary vasodilator effect in both large conduit arteries and small resistance vessels. The results of the in vitro experiment suggested that the activation of soluble guanylate cyclase of the vascular smooth muscle cell may be involved, at least in part, in the vasodilator mechanism of carboxy-PTI in large conduit arteries.

Animals↗

PubMed1994

[Anaphylactoid purpura: intestinal ultrasonographic findings].

We evaluated six children with anaphylactoid purpura for ultrasonographic changes in the small intestine. Of 16 ultrasonographic scans, eight showed abnormal findings, consisting of circumscribed hypo-echoic enlargement, reduced peristalsis, equivocal structure of the small intestinal wall and ascites in patients with abdominal pain. Follow-up ultrasonography after steroid therapy demonstrated the small intestine to be normal in four of six patients. We believe that ultrasonography is an useful diagnostic modality to detect changes in the small intestinal wall in anaphylactoid purpura and plays an important role in its differentiation from other causes of abdominal pain.

Adolescent↗

PubMed1994

[Coronary artery bypass grafting in a patient with right aortic arch associated with retroesophageal anomalous left subclavian artery].

A rare case of coronary artery bypass grafting in a patient with right aortic arch was presented. A 62-year-old man was admitted to our hospital with angina pectoris. Coronary angiography revealed total obstruction of left anterior descending artery and jeopardized collateral from right coronary artery. Aortography disclosed right aortic arch associated with retroesophageal anomalous left subclavian artery. As the symptom of neither the vascular ring nor the subclavian steal syndrome was recognized, left internal thoracic artery along with the saphenous vein was used for bypass conduit. The patient is doing well without any troubles 7 months after the operation. Attention should be made to use left internal thoracic artery in a patient with right aortic arch.

Aorta, Thoracic↗

PubMed1994

[Therapeutic efficacy of lanoconazole ointment in guinea pig model of tinea pedis, in comparison with that of cream preparations].

The therapeutic efficacy of ointment and cream preparations of lanoconazole in a guinea pig model of tinea pedis was compared. When infected animals were treated once daily with 0.25% and 0.5% lanoconazole ointments, 7 of 10 and 8 of 10 infected feet became culture-negative, respectively. In animals treated with 1% lanoconazole ointment, fungus was not recovered from any infected foot. Comparing these results with those of culture study in animals which were treated with comparable concentrations of lanoconazole cream, no significant differences were found. These studies, therefore, suggested that ointment and cream preparations of lanoconazole on topical application in the tinea pedis model would show basically equivalent therapeutic efficacy.

Administration, Topical↗

PubMed1992

[Amounts of urinary metabolites of p-chloroaniline and their half lives in a patient with acute poisoning].

The aim of this study was to elucidate the time courses of amounts of urinary p-chloroaniline (p-CA) metabolites during acute poisoning and to establish a suitable method for biological monitoring of exposure to p-CA. Urinary p-CA metabolites which were previously identified in a patient with acute p-CA poisoning were determined quantitatively over time during admission of a patient by high-performance liquid chromatography (HPLC) and by the colorimetric method of diazo-positive metabolites (DPM). The data of urinary excretion of each p-CA metabolite were fitted to two-compartment model of pharmacokinetics. Major urinary metabolites of p-CA were conjugated p-CA and conjugated 2-amino-5-chlorophenol (2-A-5-CP), and the detected amounts of 2,4-dichloroaniline (2,4-DCA) and free p-CA were small. During the rapid phase for the disappearance of each metabolite, half lives of p-CA, 2-A-5-CP and 2,4-DCA were 2.4, 1.7 and 1.7 h, respectively, and during the slow phase, they were 4.5, 3.3 and 3.8 h, respectively. Urinary p-CA occupied about 62% of the total metabolites detected in the urine, 2-A-5-CP about 36%, and 2,4-DCA about 1%. 2-A-5-CP and p-CA were detected in the urine of the patient obtained on days 3 and 4, respectively, after the poisoning, but the amount of DPM after the second day of the poisoning was in the range of that of non-exposed persons.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Disease↗

PubMed1992

[Excretion of p-chloroaniline metabolites into urine. Excretion of 2,4-dichloroaniline and p-chloroformanilide].

Previously, we identified by gas chromatography/mass spectrometry (GC/MS) urinary metabolites of p-chloroaniline (p-CA) in a patient with acute p-CA poisoning. Among these metabolites there is a possibility that 2,4-dichloroaniline (2,4-DCA) and p-chloroformanilide (p-CFA) are produced through some unknown metabolic pathways in human. In order to clarify whether 2,4-DCA and p-CFA were produced within the human body or not, an attempt was made to detect these metabolites in the patient's urine samples prepared by various pretreatments, using both GC/MS and high performance liquid chromatograph. In addition, the detection of these metabolites in non-exposed person's urine samples spiked with p-CA and 2-amino-5-chlorophenol was attempted by GC/MS using same the procedures in order to examine whether p-CA and 2-amino-5-chlorophenol excreted as metabolites were further changed to 2,4-DCA or p-CFA in the urine or not. 2,4-DCA was found abundantly in the ethereal extracts from the patient's urine samples hydrolyzed with hydrochloric, sulfuric and nitric acids, but only small amounts from intact urine samples by GC/MS. No 2,4-DCA was detected in the urine samples to which were added p-CA and 2-amino-5-chlorophenol. p-CFA was found in the ethereal samples which were extracted at acidic conditions from the patient's urine samples by GC/MS at the injection port temperature of 250 degrees C of the gas chromatograph, but the p-CFA peak disappeared at the injection port temperature of 150 degrees C.(ABSTRACT TRUNCATED AT 250 WORDS)

Aniline Compounds↗

PubMed1992

Identification of urinary metabolites of human subjects acutely poisoned by p-chloronitrobenzene.

1. Urinary metabolites from human subjects acutely poisoned with p-chloro-nitrobenzene (p-CNB) were identified by g.l.c.-mass spectrometry. 2. Eight substances, namely, a very large amount of N-acetyl-S-(4-nitrophenyl)-L-cysteine, relatively large quantities of p-chloroaniline, 2-chloro-5-nitrophenol and p-chloroformanilide produced by pyrolysis of a substance originating from p-CNB, small amounts of 2-amino-5-chlorophenol and 2,4-dichloroaniline, and traces of p-chloroacetanilide and 4-chloro-2-hydroxyacetanilide, were detected in urine samples. 3. All of the absorbed p-CNB was metabolized prior to excretion, as the parent compound was not found in urine. 4. N-Acetylated metabolites of p-chloroaniline and 2-amino-5-chlorophenol, resulting from p-CNB by metabolism, were found in only one of eight individuals indicating that this pathway is weak or may be absent in some humans. 5. A scheme for the pattern of metabolic pathways of p-CNB is proposed, and chlorination was considered to be a possible novel metabolic pathway.

Acetylation↗