Search PubMed⌕ Search

Biomedical subjects

Y Hamada

Publications and source records attributed to Y Hamada.

At least 397 records · Page 22Linked to original sources
PubMed1990

Chronic supraventricular tachycardia causes ventricular dysfunction and subendocardial injury in swine.

Chronic supraventricular tachycardia has been associated with ventricular dysfunction in humans and animals. However, this ventricular failure is poorly characterized, and the ultrastructural consequences of supraventricular tachycardia are unknown. We serially examined right and left ventricular function, endomyocardial ultrastructure, and creatine kinase activity in eight pigs at base line and again at 1, 2, and 3 wk following rapid atrial pacing. Left and right ventricular ejection fractions fell significantly from base line after 1 wk of chronic tachycardia. Three weeks of chronic pacing resulted in further deterioration in ejection fractions. Significant biventricular chamber dilatation developed and was associated with a reduction in end-diastolic wall thickness after 2 wk of tachycardia. Mitochondrial injury and diminished mitochondrial cytochrome oxidase staining of subendocardial myocytes were observed after 2 wk of tachycardia. Endomyocardial creatine kinase activity fell from control levels following 2 wk of pacing. Postmortem examination revealed a reduction in left ventricular wall thickness compared with 14 control animals. Fibrosis occurred along the subendocardial layer in paced animals, and glycogen content was also reduced. In summary, chronic supraventricular tachycardia resulted in severe biventricular pump dysfunction and chamber dilatation that were associated with ultrastructural alterations and reduced enzyme activity of the subendocardial myocytes. These ultrastructural and metabolic changes may be potential mechanisms responsible for the ventricular dysfunction and dilatation observed in this model.

Animals↗
PubMed1990

[A double cancer of the gallbladder and common bile duct associated with an anomalous arrangement of the choledocho-pancreatic ductal junction--a case report and a review of the literature].

Reported is the case of a 65-year-old woman who complained of general fatigue and itching. The cancer of the gallbladder and the common bile duct associated with anomalous arrangement of choledocho-pancreatic ductal junction was diagnosed after examination by ERCP, PTCS, US, and CT. The cancer of the common bile duct had metastasized to the pancreas, the portal vein, and the regional lymph nodes and was unresectable. It is well known that an anomalous arrangement of the choledocho-pancreatic ductal junction is highly associated with a cancer of the common bile duct or the gallbladder. But a case that is associated with double cancers is rare and only 6 cases have been reported in the Japanese literature. In addition to a discussion of this case, the literature is reviewed.

Aged↗
PubMed1990

[Surgery for postinfarction ventricular septal perforation under hypothermic fibrillatory arrest with pulsatile perfusion].

Surgery were performed by 2 different methods of myocardial protection in 17 patients with postinfarction ventricular septal perforation (VSP) from 1982 to 1989. Ten consecutive operations were performed using hypothermic fibrillatory arrest with pulsatile perfusion (VF group). Pulsatile flow was produced by an intra-aortic balloon pumping device. Other 7 consecutive VSP operations were performed using cardioplegic arrest (CP group). In the VF group, the mean age was 67 years (range 54 to 78 years), and VSP was located in the anterior wall in 7, in the inferior wall in 2, and in the anterior and inferior walls in 1 patients. The operation was performed 2.5 days after the onset of VSP. In the CP group, the mean age was 71 years (range 50 to 78 years), and VSP was located in the anterior wall in 6 and in the inferior wall in 1 patient. The operation was performed 4.7 days after the onset of VSP. Cardiogenic shock developed after septal rupture in 50% of the patients in the VF group and 71% in the CP group (N.S.). Prior to the operation, no significant differences were found in hemodynamic status between the 2 groups. Cardiac index in the VF group was higher than that of the CP group (p less than 0.05) shortly after cardiopulmonary bypass. The operative mortality rate was 10% in the VF group and 57% in the CP group. From these clinical results, hypothermic fibrillatory arrest with pulsatile perfusion can be beneficial as a method of myocardial protection during surgery for VSP and presently this has become the method of choice in our department.

Aged↗
PubMed1990

Bilateral internal mammary artery grafts for coronary artery bypass operations in children.

We performed myocardial revascularization with bilateral internal mammary arteries in eight children for coronary artery complications consequent to Kawasaki disease. Subjects included seven boys and one girl, ranging in age from 3 to 13 years (mean age, 8.3 +/- 3.4 years). The body surface area ranged from 0.65 to 1.65 m2 (average, 1.08 +/- 0.35 m2). Three patients had a previous myocardial infarction. The right internal mammary artery was anastomosed to the right coronary artery and the left internal mammary artery was sutured to the left anterior descending artery in all patients. The patients received an average of 2.4 grafts. Magnifying loupes of 3.5 X were used for anastomosis with 8-0 monofilament polypropylene sutures. Subjects were followed up from 12 to 38 months (23 +/- 10.8 months) after operation. All were doing well with no recurrence of angina, and body development was normal, including the sternum and thorax according to chest x-ray films and computed tomography of the chest. Patency of the bilateral internal mammary arteries was 100% in the early (within 1 month) postoperative period and remained so in the late (over 1 year) postoperative period. Anastomotic junctions between the internal mammary artery and the coronary artery developed well angiographically in the late postoperative period. The internal mammary artery is the graft of choice for pediatric myocardial revascularization because of its excellent long-term patency and growth potential. Bilateral internal mammary arteries should be used whenever indicated, and the use of bilateral internal mammary arteries did not adversely influence chest wall development in the children.

Adolescent↗
PubMed1990

[Surgery of aortic valvular disease with congenital bicuspid or quadricuspid aortic valve].

Twelve patients (age 18 to 69 years old) with surgical treatment for congenital bicuspid aortic valve and one (age 26 years old) for quadricuspid aortic valve were reported. These 13 patients occupied 12.3% of the total number of patients with aortic valve replacement during the same period. Among the patients with bicuspid aortic valve, 10 patients were male (83%) and 2 were female (17%). Seven patients exhibited aortic stenosis and 5 showed predominant aortic regurgitation. The mean age of patients with aortic stenosis was higher than that of patients with aortic regurgitation. (63.3 years vs 32.0 years old). Infective endocarditis occurred in 2 patients (17%). Three patients had pure aortic regurgitation without evidence of endocarditis. One 26-year-old female patient who had a quadricuspid aortic valve presented with aortic regurgitation associated with PDA. All patients underwent aortic valve replacement with no early and late deaths.

Adult↗
PubMed1990

[Surgical correction of tetralogy of Fallot with anomalous origin of left pulmonary artery from the ascending aorta].

A surgically corrected case of tetralogy of Fallot with anomalous origin of left pulmonary artery from the ascending aorta is presented. The patient was under-developed 3-year-old girl. She weighed only 1,000 grams at birth and had a systolic heart murmur and slight cyanosis. Echocardiography demonstrated the features of tetralogy of Fallot shortly after birth. Chest roentgenogram showed right ventricular enlargement, but vascular marking of lung was almost normal. Catheterization and cineangiography demonstrated the findings of tetralogy of Fallot. Final diagnosis of anomalous origin of left pulmonary artery from ascending aorta was confirmed by aortography. Surgical correction was accomplished using cardiopulmonary bypass with surface cooling. The left pulmonary artery was detached from the aorta and anastomosed to the main pulmonary artery. Pulmonary valve stenosis and severe infundibular hypertrophy were corrected, and ventricular septal defect was closed with a patch. Postoperative recovery was uneventful. On follow up after surgery, she appears to be in very good condition.

Aorta↗
PubMed1990

[A case of double bronchogenic cysts in the mediastinum].

A 42-year-old house wife had suffered from abnormal mass lesion in the right pulmonary hilum on her chest X-ray film. MRI showed another mediastinal mass between IVC and descending aorta with high T1 and T2 intensity. Thoracic CT done before MRI missed the latter lesion because only upper mediastinal scanning had been performed. At operation subcarinal and right paraesophageal cysts were successfully removed. Histological examination of the subcarinal cyst showed ciliated pseudostratified columnar epithelium lining, and its thin wall consisted of partly smooth muscle bundle, lymph node, calcification, inflammatory cell infiltration and hemorrhage. The paraesophageal cyst lined by a ciliated pseudostratified columnar epithelium, and the wall consisted of mostly fibrous connective tissue with partly smooth muscle bundle. Although the both cysts were diagnosed as bronchogenic origin, definitive bronchial glands and cartilage could not be recognized. The postoperative course was uneventful. This is the first case report of mediastinal double bronchogenic cysts appeared in the Japanese literature.

Bronchogenic Cyst↗
PubMed1989

Complete primary structure of calcium-dependent serine proteinase capable of degrading extracellular matrix proteins.

A novel calcium-dependent serine proteinase (CASP) secreted from malignant hamster embryo fibroblast Ni 12C2 degrades extracellular matrix proteins. A complementary DNA encoding CASP has been isolated with the use of oligonucleotide probes synthesized based on partial amino acid sequences of CASP. The complete amino acid sequences of CASP revealed that it has a active site at the C-terminal side. Glu rich and proEGF homologous sites are found at the N-terminal site suggesting that it is structurally similar to blood coagulation factors such as IX, X and an anticoagulation factor, protein C.

Amino Acid Sequence↗
PubMed1989

A distinct form of tau is selectively incorporated into Alzheimer's paired helical filaments.

Tau, a microtubule-associated phosphoprotein, was identified as a definite component of paired helical filaments which progressively accumulate in Alzheimer's disease brain. To learn more about tau in the aged brain, we have isolated and sequenced a cDNA clone encoding tau from a cDNA library of an aged human brain. The cloned cDNA sequence included a new insert of 93 nucleotides, which added a fourth repeat to the three-repeat type of tau already reported. Perhaps, this four-repeat type of tau is predominant in normal aged brain. In contrast, the sequence analysis of paired helical filaments showed that the integrated tau is of three-repeat type. This indicates that a distinct form of tau is selectively incorporated into paired helical filaments.

Aged↗
PubMed1989

Immunocytochemical and biochemical analysis of epidermal growth factor receptor expression in human breast cancer tissues: relationship to estrogen receptor and lymphatic invasion.

Expression of epidermal growth factor receptor (EGFR) and estrogen receptor (ER) was examined by an immunocytochemical assay (ICA) using serial cross-sections of human breast cancer tissues. Immunocytochemical results were compared with those obtained by biochemical competitive binding assay and with histological lymphatic invasion. EGFR was evaluated as positive in 17 (34.0%) out of 50 primary tumors by ICA. A significant inverse relationship of the proportion of stained cells between EGFR and ER was demonstrated. In more than one-half of the tumors that were positive for both EGFR and ER, these 2 receptors were inversely stained in relation to the distribution. In ER-negative cells, EGFR expression was more marked than in ER-positive cells. Biochemical data confirmed the immunocytochemical results, pointing to an inverse relationship between EGFR and ER content. EGFR status correlated well with the degree of lymphatic invasion but not with the number of lymph nodes with metastases.

Breast Neoplasms↗
PubMed1989

Angiography of right gastroepiploic artery for coronary artery bypass graft.

We describe the angiographic technique of grafting the right gastroepiploic artery to the coronary artery. With the femoral approach, our specially devised catheter was placed in the common hepatic artery or gastroduodenal artery. The gastroepiploic artery and graft to the coronary artery were visualized satisfactorily by manual injection of contrast media.

Angiography↗
PubMed1989

Difficult deflation of Probe balloon due to twisting the system.

While using the balloon-on-a wire device, we experienced a case of difficult deflation of the Probe balloon system. Blockage of the balloon system was possibly caused by twisting the system to reach and pass the lesion in the branch of left circumflex coronary artery. The duration of inflation was 20 min, causing prolonged ischemia.

Aged↗
PubMed1989

Multiple coronary thrombosis in a patient with thrombocytosis.

A 59-year-old woman was admitted with acute inferior myocardial infarction. Cardiac catheterization revealed total occlusion in the right coronary artery and thrombus-like filling defect in the left anterior descending coronary artery. With simultaneous intracoronary urokinase infusion to the right and left coronary arteries, the right coronary artery became patent and the thrombus in the left anterior descending coronary artery was released to the distal coronary artery. Thrombocytosis was disclosed by laboratory examination. The relationship between myocardial infarction and thrombocytosis is discussed.

Coronary Disease↗
PubMed1989

Presence of angina pectoris before acute myocardial infarction and degree of residual stenosis after coronary thrombolysis.

This study tested the hypothesis that the degree of residual stenosis after coronary thrombolysis reflected that of original stenosis presented by symptom of angina before acute myocardial infarction (AMI). The relation between the presence of angina before AMI and the degree of residual stenosis after coronary thrombolysis was observed in 57 patients with successful coronary thrombolysis for AMI. Patients with significant coronary artery stenoses other than the artery responsible for AMI were excluded from this study. In 22 patients with chronic angina for 2 weeks or longer before AMI, 14 patients had a residual stenosis of 75% or more and 8 patients had a residual stenosis of less than 75%. In 35 patients with angina for less than 2 weeks or not at all before AMI, 9 patients had a residual stenosis of 75% or more, and 26 patients had a residual stenosis of less than 75% (p less than 0.01). In the course of progression of coronary artery disease, some patients had AMI without severe underlying stenosis and others with severe underlying stenosis. Patients with chronic angina before AMI might tend to have AMI with acute occlusion superimposed on the severe organic stenosis. Patients without chronic angina before AMI would be more at risk for AMI caused by acute occlusion without underlying severe stenosis.

Aged↗
PubMed1989

Peripheral T-cell lymphomas. Immunologic and enzyme histochemical analysis of 15 cases.

Fifteen cases of peripheral T-cell lymphoma were studied to evaluate the respective properties of various histologic types using enzyme histochemical and ultrastructural examinations in addition to immunological methods. Eleven cases in an ATLA-negative group manifested various histologic patterns such as IBL-like, pleomorphic and Lennert's lymphomas in comparison with the relatively monomorphic proliferation of neoplastic lymphoid cells in the 4 ATLA-positive cases. The presence of neoplastic clear cells is characteristic of peripheral T-cell malignancies, and is likely to be found in CD4+ lymphomas. There is an occasional reaction of epithelioid histiocytes and plasma cells with eosinophils, the former being designated Lennert's lymphoma and the latter IBL-like T-cell lymphoma. Immunological examination revealed four immunophenotypic patterns: (1) CD2+3+4+8-, (2) CD2+3-4+8-, (3) CD2+3+4-8+, and (4) CD2+3+4+8+, but did not provide information concerning the intimate relationship between histologic types and immuno-phenotypes. beta-Glucuronidase reactivity, however, contributed to the distinction between helper and suppressor T-cell malignancies, suggesting its usefulness for distinguishing these two cell types and their malignant counterparts.

Adult↗