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Biomedical subjects

H Manabe

Publications and source records attributed to H Manabe.

At least 109 records · Page 6Linked to original sources
PubMed1984

Isolation of tumor disturbing factor on the proliferation of tumor cells in human serum.

The classified sediment with ethanol from sera of nude mice and humans showed a disturbing effect on L1210 cells in vitro and a lifesaving effect on L1210 cell-bearing mice in vivo. This factor was purified more than 2300-fold to a specific activity of approximately 1 X 10(5) U/mg by ethanol classified precipitation, Sephadex G-200 gel filtration, DEAE cellulose ion exchange chromatography with Nacl and pH gradient aqueous solution, and preparative polyacrylamide gel electrophoresis.

Animals↗
PubMed1984

In-vitro and clinical evaluation of cardiac valve substitutes.

One of the major causes of postoperative morbidity and mortality after valve replacement surgery is the prosthetic valve substitute itself. In this discussion, therefore, we make a fundamental evaluation of hydrodynamic valve function and present our clinical results following valve replacement with the Björk-Shiley valve prosthesis, the Hancock porcine xenograft and the Ionescu-Shiley bovine pericardial xenograft. In an experimental study using a mechanical simulator system, the pericardial xenograft displayed superior hydrodynamic characteristics compared to other two valve substitutes. Postoperative hemodynamic evaluation further indicated that the pericardial xenograft performed significantly better than the porcine xenograft regarding transvalvular pressure gradient, effective valve area and cusp opening. In addition, data from 387 patients with aortic, mitral or both types of valve replacement who had received one of the three kinds of valve substitute were analyzed. Systemic thromboembolic complications occurred in one patient with an aortic Björk-Shiley valve (0.6% per patient-year), six with mitral Hancock xenografts (2.8% per patient-year) and one with an aortic and mitral Hancock xenograft (2.2% per patient-year). The incidence of prosthetic valve endocarditis was 0.84% per patient-year for the Hancock xenograft and 1.84% per patient-year for the Ionescu-Shiley xenograft. It was concluded that the hemodynamic and antithrombogenic advantages of the pericardial xenograft proven by our mid-term follow-up study make it the valve substitute of choice. However, careful attention is required regarding prosthetic valve endocarditis tissue heart valves, which are more susceptible to infection than mechanical ones, and the long-term durability of the pericardial xenograft remains to be confirmed.

Aortic Valve↗
PubMed1984

Clinical features of rheumatic heart disease in Bangladesh.

The clinical features of 205 cases of rheumatic heart disease in Bangladesh, including unique two-dimensional echocardiographic findings, were reported, and these were compared with those of 387 Japanese cases. The percentage of mitral stenosis (MS), aortic valvular diseases including both aortic stenosis and aortic regurgitation (A), mitral stenosis with aortic valvular diseases (MS + A) were almost the same between the two countries, but that of mitral regurgitation (MR) was higher, mitral stenosis and regurgitation (MSR) was lower in Bangladesh. The mean age of the patients with mitral valvular diseases was very young and the incidence of atrial fibrillation was very low in Bangladesh. Males predominated over females in MS (male/female = 1.2/1) and the incidence of pulmonary hypertension in MS was higher in Bangladesh. A two-dimensional echocardiographic examination showed that the rough zone was heavily involved in the rheumatic process with having a narrow mitral valve orifice while the clear zone was relatively spared and pliable in many patients with MS in Bangladesh. In MR, posterior mitral leaflets were shortened and made immobile by its submitral complex which were also thickened, fused and shortened, and these resulted in a gap or non-coaptation of the two leaflets in many patients.

Adolescent↗
PubMed1984

Circulation control of experimental and clinical profound left ventricular failures by automatic left ventricular assist system.

It is desirable that circulation control of the patient using a left ventricular assist device (LVAD) should be achieved appropriately and safely. We have developed an automatic LVAD system, which can maintain the normal circulation irrespective of the severity of heart failure and can restore the failing heart by decreasing the bypass flow (BF) through the LVAD as the heart recovers. The main part of the control-drive unit is an automatic level control (ALC) system for left atrial pressure (LAP) and total flow (TF). Profound left ventricular failure (LVF) was made by complete interception of blood supply to the extent of 50% (5 goats) and 70% (5 goats) of the LV free wall. The air-driven diaphragm-type LVAD was implanted between LA and aorta. At the beginning of LVAD pumping, BF tended to be very high to keep LAP at the preset level (0-5 mmHg) and to maintain TF at somewhat higher level (120-140 ml/kg/min). The recovering heart was able to decrease LAP gradually. Since the LAP was set at a certain level, the ALC of LAP decreased BF to maintain LAP at the preset level. During the recovering stage from LVF, preset level of LAP was gradually raised while checking the pulmonary function. When natural heart output exceeded 100 ml/kg/min, LVAD was removed. The 50% LVF group recovered between 17 hours and 3 days, and 70% LVF group between 6th and 16th postoperative day. This LVAD system was then applied to the postoperative profound LVF in a MVR patient whose entire circulation was maintained normal during 14 day pumping. The failed heart gradually recovered and the pump was successfully removed. We consider that the decompression of LV will prevent overextension of impaired myocardium and simultaneously accelerate the solid scar formation. And gradual increase of LV work will promote the compensation ability of the residual myocardium. Continuous LVAD assistance can therefore earn time for the impaired myocardium to recover while maintaining normal circulation.

Adult↗
PubMed1984

[Left ventricular thrombus formation and cuspal fusion of the prosthetic valve during left heart bypass: their pathophysiological significance and echocardiographic observations].

The echocardiographic findings during left ventricular assist of a heart of a 36-year-old woman who underwent mitral valve replacement were described. Blood was bypassed from the left atrium to the aorta. Echocardiography demonstrated that the pulmonary and tricuspid valves functioned with each heart beat, but that the aortic and prosthetic mitral valves did not open, and the left ventricular wall did not contract. In the left ventricular cavity, there was a mobile and amorphous thrombus which correlated with dynamic intracavitary micro-echoes ("moya moya" echoes). With higher left atrial pressure, the left ventricular motion increased slightly, and the left ventricular dimension gradually decreased. These findings were interpreted as follows: (1) desired results were attained from the previous powerful assist, or (2) the most optimum pressure of the left atrium in relation to the left ventricle was relatively high. It has not yet been determined which is actually the case. The "moya moya" and thrombus echoes were decreased. The general condition of the heart appeared to be improved, but the prosthetic valve motion was not observed. Contrast study via an echocardiographically-guided catheter inserted retrogradely into the left ventricular cavity revealed prosthetic valve stenosis. Fusion of its cusps by fibrin was confirmed on repeat surgery. Although the patient's condition allowed removal of the left ventricular assist device after surgery, the patient died of progressive infection. Optimum powerful assist should be performed while the formation of thrombi and cuspal adhesions is being prevented by other methods, or a more mild assist may be desirable.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗
PubMed1983

Ultrastructure of the congenital epulis.

This report presents the ultrastructural features of a congenital epulis. The granular cells of the epulis were packed with numerous membrane bound cytoplasmic granules containing particles, small vesicles, and electron-dense materials. These granules were negative in immunohistochemical reaction for CEA (DAKO PAP KIT). Cytoplasmic organelles such as mitochondria, rough surfaced endoplasmic reticulum, and Golgi apparatus, were absent. Nuclei were markedly indented. Occasionally, banded intracellular collagen fibrils were observed within the cytoplasm. Some of these fibrils were surrounded by a limiting membrane, whereas others appeared to lie free in the cytoplasm. The collagen fibrils were also seen within a deep invagination of the cell surface. There was no basal lamina around the granular cells. Sporadically, mast cells with many granules containing lamellar formations were found between the granular cells. These observations support the idea that granular cells of the congenital epulis are derived from mesenchymal cells, probably fibroblasts.

Basement Membrane↗
PubMed1983

Surgical treatment for severe congenital heart diseases.

The surgical results in patients with severe congenital heart disease, who underwent surgical treatment between 1978 and 1981 at the National Cardiovascular Center, Japan, were analyzed. The surgical mortality rates were 4% for cases of ventricular septal defect associated with pulmonary hypertension in patients under 2 years of age, 16.7% for complete atrio-ventricular canal, 11% for coarctation of the aorta associated with ventricular septal defect, 40% for pure pulmonary atresia without Ebstein anomaly, 44% for total anomalous pulmonary venous return, 14.8% for transposition of the great arteries, 44% for double outlet right ventricle and 1.1% for tetralogy of Fallot. The surgical results have been improving and postoperative residua and sequelae have been decreasing through our persistent efforts. Today's main problem is a relatively poor performance in cases which need surgical intervention early in life, i.e., under 3 months of age. Therefore, we think that our effort to improve the surgical results for new-borns or very young infants is most necessary.

Aortic Coarctation↗
PubMed1983

Myocarditis in children--Clinical findings and myocardial biopsy findings.

Eight children with myocarditis underwent a cardiac catheterization study and right ventricular endomyocardial biopsy. The degree of histological changes of the biopsy specimens correlated well with the severity of the clinical manifestations. Patients who had evidence of residual functional impairment had biopsy findings compatible with their clinical course.

Adolescent↗