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Biomedical subjects

S Yabuki

Publications and source records attributed to S Yabuki.

At least 19 recordsLinked to original sources
PubMed1992

Preventive effect of exercise training on recurrent stenosis after percutaneous transluminal coronary angioplasty (PTCA).

The purpose of this study is to evaluate whether exercise training for 12 weeks prevents the development of restenosis after percutaneous transluminal coronary angioplasty (PTCA). Symptom-limited treadmill exercise with thallium-201 myocardial single photon emission computed tomography (SPECT) was performed one and 13 weeks after PTCA in 18 patients with exercise training and in 20 patients without. For quantitative analysis, the average count of region of interest in the hypoperfused area on the polar map was calculated. A percentage T1 uptake was determined by dividing average count of the hypoperfused area by that of a normal reference area at an initial image (%IU) and a delayed image (%DU). A percentage redistribution (%RD) was obtained by subtracting %IU from %DU as the parameter of residual ischemia in the hypoperfused area. Total treadmill exercise duration and maximal pressure rate product 13 weeks after PTCA increased significantly (p less than 0.01) in the trained group, whereas there was no significant change in the untrained group. %DU increased significantly (p less than 0.01) in the trained group, whereas there was no significant change in the untrained group. %RD decreased significantly (p less than 0.01) in the trained group, whereas there was no significant changes in the untrained group. The restenosis rates at the third month after PTCA was 17% (3/18) in the trained group and 40% (8/20) in the untrained group. These findings suggest that in patients with coronary artery disease exercise training improves myocardial perfusion by preventing the progression of coronary artery stenosis after PTCA.

Aged↗
PubMed1992

[A case of ornithine transcarbamylase deficiency presenting severe symptoms in adulthood].

An adult female case of ornithine transcarbamylase (OTC) deficiency is presented in the following. The patient had had past episodes of drowsiness with a duration less than a few minutes several times a year during childhood. She suddenly became comatose at 25 years of age, and died after 13 months of persistent vegetative state. Blood chemistry showed hyperammonemia with no liver cirrhosis or portal-systemic shunt. Plasma amino acid analysis indicated elevated glutamate and glycine levels, and plasma levels of citrulline and arginine to be low. The urinary orotic acid level was high. OTC activity of a liver specimen was 65 percent of the normal level. This is a rare case demonstrating hyperglycinemia and an elevated level of serum OTC. The importance of ruling out defective ureagenesis in adults with disturbed consciousness should be emphasized.

Adult↗
PubMed1992

[Effects of exercise training on restoration of residual myocardial ischemia after percutaneous transluminal coronary angioplasty].

The effects of exercise training on the restoration of hibernating myocardium after percutaneous transluminal coronary angioplasty (PTCA) were evaluated. Symptom-limited treadmill exercise with thallium-201 myocardial single photon emission CT (SPECT) was performed at one and 13 weeks after PTCA in 15 patients with training and in 15 control patients without training who had no restenosis on repeat angiography. For quantitative analysis, counts for the regions of interest (ROI) were calculated in the hypoperfused area on the polar map. Percent T1 uptake was determined by dividing counts of the hypoperfused area by counts of a normal reference area on the initial image (%IU) and delayed image (%DU). The difference between %DU and %IU, defined as percent redistribution (%RD), was a parameter of residual ischemia in the hypoperfused area. %DU increased significantly in the trained group (65 +/- 11 to 73 +/- 9.3%, p < 0.01) and in the untrained group (66 +/- 14 to 70 +/- 15%, p < 0.05). %RD decreased significantly in the trained group (6.3 +/- 3.2 to 2.8 +/- 2.3%, p < 0.01); whereas, there was no significant change in the untrained group (6.1 +/- 2.8 to 5.2 +/- 3.8%). These findings suggest that, after successful PTCA, exercise training helps alleviate myocardial ischemia, probably by fostering the promoting effects which restore the hibernating myocardium.

Aged↗
PubMed1992

[An experimental study of determining the appropriate frequency of radiofrequency catheter ablation in vitro and in vivo for ventricular tachycardias].

The purpose of this study was to examine the appropriate frequency of radiofrequency catheter ablation (RFA) for ventricular tachycardia. Radiofrequency energy generated by a device in which the frequency could be changed, was delivered from an electrode catheter with an electrode tip-width of 4 mm. RFA was performed for 10 seconds with 20W (50V x 0.4A) using 7 different frequencies from 10 to 500 kHz on ventricular myocardium in vitro and in anesthetized dogs. The ablated lesion was significantly larger with RFA of 200-300 kHz in both surface area and depth (p less than 0.05). The appearance of ventricular arrhythmia during RFA increased as the frequency decreased, and one dog applied with RFA of 100 kHz had spontaneous ventricular fibrillation resulting in death. All dogs with frequency less than 100 kHz had a muscle cramp during RFA. We conclude that appropriate frequency seems to be 200-300 kHz to obtain a large ablated lesion, and a frequency higher than 300 kHz seems suitable to avoid arrhythmia. We also conclude that a frequency under 100 kHz should not be used.

Animals↗
PubMed1992

[Unilateral choreic movements in idiopathic hypoparathyroidism].

We report a patient with idiopathic hypoparathyroidism associated with unilateral calcification of the basal ganglia and contralateral choreic movements. A 66-year-old woman was admitted to our hospital because of involuntary movements of the left limbs. Two years before the present admission, she had operations for bilateral cataracts. Eight months before admission, she had an onset of severe carpal spasms and pain in both arms and legs. These symptoms improved after one month's rest in a hospital. About a month before admission, she noted progressive difficulty in using her left hand, followed by difficulty in walking due to the abnormal involuntary movement of the left lower limb. Two weeks before admission her carpal spasms appeared again, bilaterally. On admission, she was alert. The general physical examination was normal. Neurological examination revealed choreic movements in the left hand, arm, leg and neck, and grimacing of the left face. She also complained of the spasms and pain in her hands, dysarthria and shortness of the breath. Chvostek and Trousseau signs were positive. Laboratory examination revealed marked decrease in serum calcium level (2.57 mEq/ml) and increase in inorganic phosphorus level (6.40 mEq/ml). Serum level of parathyroid hormone was less than 10 pg/ml. Ellthworth-Howard test was positive, in that the infusion of parathyroid hormone (100 u) elicited a marked increment of the urinary excretions of phosphorus and cAMP. X-ray examination of the spine revealed ossification of the posterior longitudinal ligament in the cervical region. CT-scans of the brain revealed calcification in the region of right globus pallidus and putamen.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1992

[Is radiofrequency catheter ablation available for treatment of ventricular tachycardias?--Effects of sequential unipolar applications using multiple electrode catheter].

The purpose of this study was to examine the effects of radiofrequency energy delivered to the canine endocardium in sequential unipolar applications using multipolar electrode catheter for treatment of ventricular tachycardias. Radiofrequency energy generated by the newly designed device (500 kHz) was delivered to the ventricular myocardium by a quadripolar electrode catheter. The device could indicate output and voltage and could calculate myocardial impedance. In order to determine the power of the ablation in vivo, sequential unipolar application was performed with various output in vitro. A continuous endocardial ablation was achieved with output beyond 15 W and with duration of 5 sec per one pole. According to our measurement, the myocardial impedance in vivo was about three times as large as that in vitro. Therefore, minimal output of 45 W in vivo was applied in the same manner in vitro, which resulted in continuous belt-shaped endocardial ablated lesion. Ventricular stimuli after sequential unipolar applications did not induce ventricular tachycardia in any of the dogs. We conclude that radiofrequency sequential unipolar application using the newly designed device produces a large ablated area and may be suitable for ablation of the foci of ventricular tachycardias.

Animals↗
PubMed1991

Chronic alcoholism impedes the recovery of renal function following renal ischemia.

The recovery of renal function following renal ischemia was studied using rats fed for 1-, 3-, and 5-week periods with an alcoholic diet (ethanol provided 36% of total calories). Renal ischemia was produced by clamping the renal artery and vein for 20 min. Renal function was determined 24 hr after the ischemia. In the absence of ischemic insult, the renal function of rats fed with an alcoholic diet for 1, 3, and 5 weeks was not significantly different from those of nonalcoholic rats. In nonalcoholic rats, renal function (24 hr postischemia) were: glomerular filtration rate (GFR) 430.4 +/- 29.6 microliters/min/g KW (kidney weight), renal plasma flow rate (RPFR) 1.4 +/- 0.17 ml/min/g KW, and fractional sodium excretion (FENa) 2.0 +/- 0.04% (mean +/- SE). Postischemic renal function of rats on 1- and 3-week alcoholic diets were essentially the same as that of the control rats. However, the 24-hr postischemic renal function of 5-week alcoholic diet rats was significantly depressed. The values were only 117.2 +/- 35.2 microliters/min/g KW (p less than 0.05) for GFR, 0.31 +/- 0.12 ml/min/g KW (p less than 0.05) for RPFR, and 7.46 +/- 3.59% for FENa. The present results demonstrate that the rat kidney subjected to prolonged alcohol ingestion was more susceptible to renal insult than a nonalcoholic kidney.

Alcoholism↗
PubMed1991

Beneficial effects of the urinary trypsin inhibitor urinastatin on renal insults induced by gentamicin and mercuric chloride (HgCl2) poisoning.

The authors investigated the protective effects of the urinary trypsin inhibitor urinastatin on acute renal failure induced in rats by gentamicin (240 mg/kg body weight i.p. for 3 days) and by mercuric chloride (3 mg/kg s.c.). In rats injected with gentamicin, glomerular filtration rate (GFR), renal plasma flow (RPF), and percent fractional sodium excretion (%FENa) were 151 +/- 51 microliters/min/100 g body weight, 0.69 +/- 0.31 ml/min/100 g and 0.73 +/- 0.32, respectively, whereas in rats given 100,000 U of urinastatin the renal function was significantly ameliorated (GFR 318 +/- 43 microliters/min/100 g RPF 1.41 +/- 0.35 ml/min/100 g), although the %FENa (0.46 +/- 0.26) was not significantly improved. A 50,000-unit dose of urinastatin prevented the deterioration of renal function to some extent following administration of gentamicin: GFR 219 +/- 66 microliters/min/100 g and RPF 0.93 +/- 0.43 ml/min/100 g. In the study using mercuric chloride, treatment with 75,000 U of urinastatin protected the kidney from HgCl2 poisoning, yielding values of 294 +/- 93 microliters/min/100 g (GFR), 1.03 +/- 0.41 ml/min/100 g (RPF), and 1.44 +/- 0.72 microliters/min/100 g (%FENa) as compared with respective values of 169 +/- 48 microliters/min/100 g, 0.7 +/- 0.18 ml/min/100 g, and 2.22 +/- 1.35 in the untreated rats. Renal histology revealed mild to moderate tubular epithelial changes in untreated rats, but preservation of an almost normal tubular structure in urinastatin-treated rats in both studies.

Animals↗
PubMed1991

[Prediction of severity of coronary artery disease by treadmill exercise testing].

Coronary angiography was performed in 250 patients with a significant ischemic ST segment change detected by symptom-limited maximum treadmill exercise testing, and relationship between anatomical severity of coronary artery disease and parameters in exercise testing was studied. The age of the patients ranged from 34 to 76 years (188 men, 62 women). One-vessel disease (1VD) was presented in 82 patients, two-vessel disease (2VD) in 42, three-vessel disease or left main coronary disease (3VD) in 26, and no significant stenosis was presented in 100 subjects (Normal). Functional aerobic impairement (FAI) was evaluated in each group as a parameter of exercise capacity, myocardial aerobic impairment (MAI) and heart rate impairment (HRI) were also evaluated as a parameter of maximum myocardial oxygen requirements and maximum heart rate, respectively. Using these parameters, discriminant analysis was performed to compare the group with significant coronary artery disease and the Normal group. Also, to compare the group with multi-vessel disease and the group with less than 2VD. Also, the 3VD group and the group with less than 3VD. FAI, MAI and HRI were significantly different (p less than 0.0001) in each group. The discriminant formula to separate the group of significant coronary artery disease from the Normal group was Z = -1.049 + 0.02 [FAI] +0.08 [MAI] +0.03 [HRI]. According to this formula, sensitivity was 92.5% and specificity was 71.5%. The discriminant formula to separate the group with multi-vessel disease from the group with less than 2VD was Z = -4.731 + 0.07 [FAI] +0.106 [MAI] +0.02 [HRI]. According to this formula, sensitivity was 96.3% and specificity was 78.8%.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1991

[Coronary collateral vessels during the early period of acute myocardial infarction: their development].

The aim of this study was to investigate the incidence and development of coronary collateral circulations in patients with acute myocardial infarction (AMI). We categorized 165 patients with persistent 100% occlusion of the infarct-related artery into 6 groups according to the time from the onset of AMI to angiography. Group I consisted of 55 patients evaluated within 6 hours after the onset of AMI; Group II, 28 patients, between 6 and 12 hours after the onset; Group III, 12 patients, between 12 and 24 hours after the onset; Group IV, 11 patients, between 2 and 13 days after infarction; Group V, 46 patients, between 14 and 44 days after infarction; and Group VI, 13 patients, more than 45 days after infarction. Collateral vessels were applied a numerical score between 0 and 3 according to the degree of opacification of the native vessel distal to the occlusion. In 58%, 79%, 67%, 73%, 89%, and 92%, patients of Groups I to VI had evidence of collateral vessels, respectively. Well-developed collaterals were observed in 24% of Group I compared with 50%, 58%, 55%, 73% and 69% of patients in Groups II to VI, respectively. The mean coronary collateral scores were 0.9 +/- 0.1, 1.4 +/- 0.2, 1.4 +/- 0.3, 1.6 +/- 0.4, 2.0 +/- 0.2 and 2.2 +/- 0.3 for Groups I to VI, respectively. Patients with preinfarction angina had more well-developed collateral circulations than did patients without it, however, there was no significant correlation between the duration of previous angina and extent of coronary collaterals.

Adult↗
PubMed1991

[Cardiac rehabilitation in patients with acute myocardial infarction: assessments with T1-201 myocardial scintigraphy].

The effects of exercise training on myocardial perfusion during the first 3 months after acute myocardial infarction (AMI) were assessed by exercise myocardial scintigraphy and fibrinolytic examinations. Symptom-limited treadmill exercise with thallium-201 myocardial single photon emission CT (SPECT) and fibrinolytic examinations (tissue plasminogen activator antigen: tPA, plasminogen activator inhibitor-1 antigen : PAI-1) were performed 2 and 14 weeks after AMI in 13 patients with exercise training and in 12 patients without exercise training. For quantitative analysis, counts of region of interest in the infarct area and normal reference area were calculated on a polar map obtained from myocardial SPECT. Severity of the hypoperfused myocardium was determined as an initial percent uptake (%IU) and a delayed percent uptake (%DU). The difference (%DU-%IU) was defined as a parameter of residual ischemia in the infarct area (%redistribution : %RD). Total treadmill exercise duration according to the Bruce protocol increased significantly in the training group (351 +/- 89 to 431 +/- 118 sec, p < 0.01); whereas, there was no significant change in the non-training group (340 +/- 95 to 356 +/- 123 sec). In the training group the pressure-rate product and %DU increased significantly (225 +/- 55 to 259 +/- 58 mmHg.beats/min x 100, 59 +/- 19 to 65 +/- 20%, p < 0.01, respectively), and %RD decreased significantly (8.8 +/- 6.7 to 4.8 +/- 4.5%, p < 0.01), but there was no significant change in the non-training group (231 +/- 89 to 240 +/- 86 mmHg.beats/min x 100, 56 +/- 17 to 57 +/- 12% and 7.4 +/- 5.5 to 6.2 +/- 6.5%, respectively).(ABSTRACT TRUNCATED AT 250 WORDS)

Coronary Circulation↗
PubMed1991

[An experimental study on the alteration of myocardial tissue by radiofrequency catheter ablation: differences according to the frequency and the device].

To evaluate the alteration of myocardial tissue by radiofrequency (RF) catheter ablation according to differences of the frequency and the device, we applied RF catheter ablation to canine right ventricular myocardium in vitro. The devices delivering RF energy were LL-49(0. 49MHz, fixed voltage mode), RA-50 (13.56MHz, fixed watt mode) and HAT200 (0.52MHz, fixed watt mode with the capability of temperature adjustment). After RF catheter ablation were performed with a unipolar electrode catheter at various output under the same condition of contact, the ablated lesions by each device were compared. Histologically, we recognized coagulation layer with the necrosis of endocardium and the dissociation of myocardium in each experiment. The degree and the size of ablation layer was significantly larger in lower frequency delivery (p less than 0.05) and was significantly smaller by using the device with temperature adjustment as compared with the others (p less than 0.05). It was suggested that the alteration of myocardial tissue ablated with RF energy differ according to the frequency and the mode of output adjustment of the device.

Animals↗
PubMed1990

Out-of-hospital sudden cardiac death following myocardial infarction in urban population.

Samples of out patient sudden cardiac deaths in Kanagawa Urban prefecture from 1972-1987 and coronary risk factors were studied to determine the increase and/or decrease of myocardial infaction deaths. On the whole death from myocardial infarction increased chronologically, and the rate for females tended to be increased further. The age adjusted myocardial infarction deaths doubled over 10 years, while non-ischemic acute cardiac failure decreased with each generation. Other cardiac diseases tended to be reduced. Cigarette smoking was the highest in advanced countries in male. These findings suggest that deaths from myocard infarction approximately doubled in 10 years in all out-of hospital sudden cardiac deaths. Cigarette smoking from a young age was as great risk as future ischemic heart disease.

Adult↗
PubMed1990

[The effect of percutaneous transluminal coronary recanalization (PTCR) on late potentials detected by signal-averaged electrocardiogram in patients with previous myocardial infarction].

The purpose of this study was to assess the effect of percutaneous transluminal coronary recanalization (PTCR) on late potentials (LP) in patients with previous myocardial infarction (MI). The signal-averaged ECG was recorded by Fukuda VCM-3000 in 54 patients with anterior MI (average of 32 months after onset of MI). Fifty four patients were divided into two groups: Group A was comprised of 29 patients who underwent PTCR, and Group B was comprised of 25 patients who didn't receive PTCR. Ventricular arrhythmias detected by 24 hour Holter monitoring, and left ventriculographic findings were also evaluated. The presence of LP was defined as low amplitude signals (less than 15 microV) in the last 40 msec of the filtered QRS complex. The incidence of LP was significantly higher in Group B than in Group A (32% vs 7%, p less than 0.01). The presence of PVCs and ejection fraction (EF), LV end-diastolic volume (EDV), LV end-systolic volume (ESV) and % abnormally contracting segment (% ACS) were not significantly different in each respective groups. However, ESV and % ACS were significantly larger (p less than 0.05), and EF was significantly smaller (p less than 0.01) in patients with LP (+) than in patients with LP (-). LP was present in two patients who had undergone PTCR (TIMI grade 2) unsuccessfully, whereas it was not present in the 27 patients with successful PTCR (TIMI grade 3). It was concluded that successful recanalization of the infarct-related arteries may reduce the incidence of LP.

Aged↗
PubMed1990

[A case of mitochondrial myopathy with mononeuritis multiplex].

A case of mitochondrial myopathy with mononeuritis multiplex was described. A 55-year-old man was hospitalized because of blepharoptosis and muscle weakness. His mother also showed blepharoptosis in her elderly stage of life. He had been healthy until 46 years of age, when he first noticed difficulty of speech, followed by bilateral blepharoptosis, weakness of upper limbs, and sensory disturbance in the left occipital, and left upper and lower extremities. These symptoms progressed slowly. On admission, bilateral blepharoptosis was recognized. Slightly to moderate muscle wasting and weakness were observed in the face, neck, trunk, and extremities. Areflexia was observed in the upper extremities. Paresthesia was observed in the left occipital and left hip, and superficial sensation was impaired in the left upper and lower extremities. Electromyographic examination of extremities showed neurogenic changes in the distal muscles and myogenic changes in the proximal muscles. Motor conduction velocities were normal, but sensory conduction velocities decreased in amplitude on the left upper extremity and were not evoked on the left lower extremity. Muscle biopsy specimen revealed numerous "ragged-red" fibers. Cytochrome c oxidase stain showed a decrease in intensity of staining. A sural nerve biopsy showed slight axonal degeneration and slight loss of nerve fibers. Biochemical analysis on biopsy muscle showed partial deficiency of cytochrome c oxidase activity.

Humans↗
PubMed1990

Do the H2-receptor antagonists, cimetidine and famotidine, modify the degree of renal recovery following renal insult?

The effects of two different H2-receptor antagonists, cimetidine and famotidine, on the acute renal failure induced by 20 min of renal artery occlusion and gentamicin (240mg/kg BW, s. c., for 3 days) were investigated in Sprague-Dawley rats. The animals were treated with either cimetidine (80 or 160 mg/kg BW) or famotidine (4 or 8 mg/kg BW) mixed in the drinking water for 7 days. The low dose of cimetidine and famotidine did not alter the renal function in the absence of renal trauma. However, the high dose of cimetidine or famotidine decreased the GFR by 32% and 22%, whereas RPFR increased by 46% and 62%, and % FENa by 92% and 558%, respectively. The data for the renal function obtained 24 hrs after 20 min of renal ischemia demonstrated a decrease of 54% in GFR, a decrease of 47% in RPFR and an increase of 370% in %FENa over the non-ischemic control values (p less than 0.05). Cimetidine (80 mg/kg BW) or famotidine (4 mg/kg BW) did not modify the recovery of renal function following the ischemic insult, showing 55% and 539% decreases in GFR, 74% and 101% increases in RPFR, and 393% and 461% increases in %FENa over the non-ischemic control rats, respectively. Famotidine reduced the decrease in RPFR significantly during the recovery period following ischemia. In the gentamicin study, gentamicin treatment was found to lower the renal function significantly.(ABSTRACT TRUNCATED AT 250 WORDS)

Acute Kidney Injury↗