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Biomedical subjects

Y Hirota

Publications and source records attributed to Y Hirota.

At least 325 records · Page 18Linked to original sources
PubMed1988

Angiographic comparison of the internal mammary artery graft and the saphenous vein graft within 2 months and 6 to 12 months after coronary artery bypass surgery.

Angiographic status of the saphenous vein graft (SVG) and the internal mammary artery graft (IMAG) anastomosed to the left anterior descending artery were compared at two different postoperative periods; - within 2 months and at 6 to 12 months after the operation. In 50 SVGs and 35 IMAGs which were studied at the early postoperative period, the rate of intact, stenosed and occluded grafts were almost the same in these two kinds of grafts. However, in 35 SVGs and 25 IMAGs which were studied at the later period, the stenosis of SVG increased significantly while IMAG remained intact. The rate of intact, stenosed and occluded grafts at postoperative 6 to 12 months were 71%, 23% and 6% in SVG, and 88%, 8% and 4% in IMAG, respectively. Considering the better angiographic quality of IMAG, use of IMAG to bypass the most important coronary artery should be considered especially when the patients are younger.

Constriction, Pathologic↗
PubMed1988

Depressed myocardial contractility in mitral stenosis--an analysis by force-length and stress-shortening relationships.

To determine whether low ejection fraction (EF) in mitral stenosis (MS) is the result of depressed contractility or is mediated by other factors, left ventricular (LV) function was analyzed by force-length and stress-shortening relationships. Thirty patients without heart disease served as normal controls (Group 1). Forty-three patients with MS were divided into 2 subgroups: Group 2 (n = 19) had EF within one standard deviation of the mean of Group 1, and Group 3 (n = 24) had EF below it. Normal EF (Group 2) was associated with low preload (end-diastolic stress) and low afterload (end-systolic stress), and preload and afterload were in the normal range in patients with low EF (Group 3). A significant negative correlation was observed in the whole group of patients with MS between EF and end-systolic stress (Y = -0.14X + 72.8, r = -0.61, p less than 0.001), and a positive correlation between end-systolic stress and volume (Y = 1.39X + 65.4, r = 0.45, p less than 0.01). These observations suggest that systolic shortening and end-systolic volume of the left ventricle are in part governed by afterload in this disease. It is concluded that low EF of MS is not mediated by reduced preload or inappropriately elevated afterload, and contractility of the ventricle is mildly depressed in MS.

Adult↗
PubMed1988

Detection of deoxyribonucleoside-triphosphate imbalance death-induced DNA double strand breakage in FM3A cells by orthogonal-field-alternation gel electrophoresis (OFAGE).

The mechanism of intracellular deoxyribonucleoside-triphosphate (dNTP) imbalance death of mouse mammary tumor FM3A cells was studied. When the cells were exposed to 5-fluorodeoxyuridine, deoxyadenosine, or 2-chlorodeoxyadenosine, dNTP pool imbalance resulted. The imbalance was followed by DNA double strand breaks and subsequent cell death. The DNA double strand breaks have been directly examined by means of orthogonal-field-alternation gel electrophoresis (OFAGE). Fragmented DNA band appeared to be approximately 100-200 kb in size.

Animals↗
PubMed1988

Optimal timing for valve replacement in chronic aortic regurgitation: analysis based on the myocardial contractility and postoperative prognosis.

Left ventricular (LV) function was evaluated considering force-velocity and stress-shortening relationships in 14 asymptomatic (Group 1), 18 symptomatic patients (Group 2), and 53 normal subjects (Group 3) to determine the optimal time for valve replacement in patients with chronic aortic regurgitation (AR). Valve replacement was recommended for all Group 2 patients and for one patient in Group 1, who had sustained ventricular tachycardia. There was one operative death and five deaths remote from surgery; one patient in Group 1 died suddenly of undetermined cause, and four patients in Group 2 died of congestive heart failure (CHF). The LV end-systolic volume index (ESVI) was greater than 100 ml/m2 in the five patients whose death was unrelated to surgery (remote deaths). ESVI was less than 50 ml/m2 in all but two patients in Group 1, and more than 40 ml/m2 in all cases in Group 2. The index of preload, end-diastolic stress (sigma ed), was increased in Groups 1 and 2 as compared with Group 3. A significant positive correlation was observed between end-systolic stress (sigma es) and ESVI (r = 0.71, p less than 0.001) in patients with AR, and this linear line was not as steep as that of Group 3. Afterload (sigma es) and ejection fraction (EF) in Group 1 were within normal range, afterload was normal but EF was reduced in mildly symptomatic patients in Group 2, and severely symptomatic patients had markedly reduced EF and elevated afterload. There was a close correlation between ESVI and end-diastolic volume index (EDVI), and this was expressed as an exponential curve (Y = 21.69e0.006x, r = 0.88, p less than 0.001). This indicates that the rate of shortening of the muscle fiber deteriorates exponentially with enlargement of the ventricle. These observations suggest that in AR patients: 1) afterload and contractility of the ventricle remain normal in the majority of asymptomatic patients by means of compensatory hypertrophy and preload elevation (preload reserve), 2) deterioration of contractility seems to be the factor initiating CHF, and 3) progression of CHF is due to further deterioration of contractility in addition to elevation of afterload (afterload mismatch). It is concluded that careful observations are necessary when ESVI exceeds 50 ml/m2 in asymptomatic patients. Valve replacement is recommended when such patients develop symptoms of CHF, or either when EF falls to less than 50% or ESVI exceeds 100 ml/m2, even if patients remain asymptomatic.

Aortic Valve↗
PubMed1988

[A case of non-Hodgkin lymphoma with complete remission achieved by carboplatin].

The patient was a 63-year-old female, who was admitted to the National Nagoya Hospital with complaints of left cervical and bilateral axillary lymphadenopathy on 12 May, 1987. Since May 1985, with the diagnosis of non-Hodgkin lymphoma, she had been successfully treated with combination chemotherapy (VEPA) and radiotherapy at another hospital. Left axillary lymphode biopsy revealed a diagnosis of non-Hodgkin lymphoma, diffuse large cell type. Then, she was given intravenous administration of carboplatin (400 mg/body) on 26 May, 1987. After a single course of this regimen, the lymphnode swelling subsided, and she achieved complete remission on 6 June. Thereafter, she was placed on the maintenance chemotherapy of carboplatin (400 mg/body) every 5 weeks. Through the whole course of this patient, the serum levels of blood urea nitrogen and creatinine were normal, and she did not notice nausea, vomiting and peripheral neuropathy. To our knowledge, this is the first report of complete response by the administration of carboplatin for non-Hodgkin lymphoma.

Antineoplastic Agents↗
PubMed1988

[Advanced sequelae of apical hypertrophic cardiomyopathy: report of two cases with wall motion abnormalities].

In view of the paucity of reports describing symptoms of increased degree, and deterioration of left ventricular systolic function in patients with apical hypertrophic cardiomyopathy (apical HCM), two cases with congestive heart failure and progressive thinning of previously hypertrophied apical portions of the left ventricle are reported. These were among 13 patients observed from eight to 10 years. Case 1: A 56-year-old man was diagnosed as having apical HCM at the age of 49 years. Severe left ventricular hypertrophy and prominent ST-T changes were observed on ECG during his first admission. His left ventricular end-diastolic pressure (LVEDP) was 24 mmHg and a left ventriculo-gram revealed a decrease in the left ventricular cavity in the apex and marked hypertrophy of the apical wall. Moderate interstitial fibrosis without hypertrophy or disarray of myocytes was observed in a left ventricular endomyocardial biopsy specimen. In two episodes of cardiac arrest he was successfully resuscitated at the age of 50 years. At the age of 55 years, two-dimensional echocardiography revealed thinning and abnormal motion in the apical wall, and a defect in 201T1 accumulation was observed in the same region by perfusion scintigraphy. This patient was readmitted with a diagnosis of cerebral embolism at the age of 56 years. Cardiac catheterization revealed normal LVEDP (8 mmHg), and a left ventriculogram revealed an aneurysm in the left ventricular apex with normal major epicardial coronary arteries. He has been under treatment with antiarrhythmic medications, calcium antagonists and anticoagulants, and has become relatively asymptomatic. Case 2: A 69-year-old-man was diagnosed as having apical HCM after a complete evaluation, including cardiac catheterization, at the age of 59 years. His LVEDP was elevated (17 mmHg), and a left ventricular angiogram revealed marked hypertrophy localized to the apex. Ejection fraction was 64%. A left ventricular endomyocardial biopsy revealed interstitial fibrosis without hypertrophy of myocytes. Thereafter, he has been followed as a New York Heart Association functional class III to IV with occasional elevation of cardiac enzymes but without chest pain or acute changes in his ECGs. However, atrial fibrillation with complete right bundle branch block developed at the age of 60 years. Apical wall thinning and dyskinesis were diagnosed by 2D echocardiography and a defect in the 201T1 accumulation was observed at about 65 years of age. He was readmitted in severe cardiac failure at the age of 69 years, and he was diagnosed as having cardiac asthma with pulmonary capillary wedge pressure of 35 mmHg.(ABSTRACT TRUNCATED AT 400 WORDS)

Aged↗