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Biomedical subjects

O Yamada

Publications and source records attributed to O Yamada.

At least 163 records · Page 9Linked to original sources
PubMed1990

Variations in growth capacity of HIV in peripheral blood mononuclear cell preparations from different individuals.

To investigate whether there are variations in the growth capacity of HIV in peripheral blood mononuclear cell (PMBC) preparations from different individuals, PBMC cultures prepared from 27 healthy donors were infected with the fresh HIV-1 isolates JH/3 or JMH/1. After infection of the PBMC with HIV, the culture fluid was checked for infectivity (TCID50) and the level of p24 antigen. Significant diversity was observed in these values in different individuals. No correlation between the percentage of CD4-positive lymphocytes or the growth ability of PBMC and TCID50 was shown. Whether PBMC was infected with JH/3 or JMH/1 also made no difference. In some cases, however, the culture fluid possessed high (or low) p24 levels despite a low (or high) infectious virus yield. The E-rosette-positive cell fraction was separated from the PBMC preparations which showed the highest and the lowest virus yield, and the yield was determined after infection with JMH/1. The difference in virus yield and the TCID50/p24 ratio between these donors was also observed in these T-cell-enriched cell cultures. The results suggest that variations in the growth capacity of HIV in different PBMC preparations are due to the T-cell population and that the source of the PBMC influences not only the binding of the virions onto the cell surface but also the replication of the virus in the cell.

Adult↗
PubMed1990

[Ectopic production of amylase by a non-producing type of multiple myeloma].

The patient was a 64-year-old woman who was admitted to our hospital because of lumbago. A diagnosis of multiple myeloma (non-producing type) was made, based on (1) the presence of multiple osteolytic lesions, (2) hypercellular marrow with 64.2% plasmacytoid malignant cells, (3) no monoclonal gamma-globulin was detected in the serum and urine, and (4) abnormal monoclonal gamma-globulin was also not detected in the cytoplasm and membranes of these malignant cells. After several courses of chemotherapy, a pleural effusion infiltrated by myeloma cells developed and the patient's serum contained a markedly increased amylase activity of salivary-type. Amylase activity was also detected in vitro in the supernatant of cultured myeloma cells established from the patient's pleural effusion. The presence of alpha-amylase in the myeloma cells, which were derived from pleural effusion, was demonstrated immuno-histochemically. These observations indicates that amylase was ectopically produced by these myeloma cells. Interestingly, 14 out of 20 metaphases in the cells derived from pleural effusion showed translocation of 1p22 near the region of 1p21, where the amylase gene was assigned.

Amylases↗
PubMed1990

[Long-term results of mitral valve replacement using glutaraldehyde-treated porcine bioprostheses--comparison of the Hancock and the Liotta valves].

Long-term results of mitral valve replacement using glutaraldehyde-treated porcine bioprostheses were evaluated. The subjects were 77 patients with the Hancock valve (Hancock group) and 60 with the Liotta valve (Liotta group) who survived operation. The maximum follow-up was 14 years and 8 years, and the cumulative follow-up was 631 patient-year (p-y) and 301 p-y in the Hancock and Liotta groups. The actuarial survival rate at 8 years was 80.1 +/- 4.6% for the Hancock group and 88.1 +/- 4.2% for the Liotta group, and there was no significant difference in survival rate between the both groups. The actuarial survival rate at 14 years was 74.3 +/- 5.9% for the Hancock group. The valve-related complications in the Hancock and the Liotta groups were as follow; thromboembolism 1.9%/p-y vs 1.3%/p-y, bleeding 0 vs 0.7%/p-y, perivalvular leak 0.3% vs 0, infection 0.3%/p-y vs 0.7%/p-y, primary tissue failure (PTF) 3.3%/p-y and all valve-related complications 5.9%/p-y vs 6.0%/p-y. There was no significant difference in valve-related complications between the both groups. However, the actuarial event free rate of PTF was significantly lower in the Liotta group than the Hancock group between 4 and 7 years after operation (100% vs 88.8 +/- 4.3% in the 4th year p less than 0.01, 87.7 +/- 4.4% vs 73.5 +/- 8.0% in the 7th year, p less than 0.05). Although the both anti-thrombogenicity and anti-inflammation were acceptable in the porcine bioprostheses, this prosthesis is now used only in the selected patients because of the limited long term durability of this valve.

Adult↗
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

[Report of a case successfully weaned from long left ventricular assist with complete recovery after coronary artery bypass grafting].

A 45-year-old female underwent coronary artery bypass grafting (CABG) due to medically uncontrollable unstable angina. After completion of CABG, left ventricular contraction was remarkably diminished to maintain systemic circulation. Because intraaortic balloon pumping and veno-arterial bypass with large amount of catecholamines could not improve left ventricular wall function, we decided to use left ventricular assist device (LVAD). After application of LVAD, the patient could easily be weaned from cardio-pulmonary bypass. LVAD was used for 25 days and the patient was successfully weaned from LVAD too, and are now living 6 months postoperatively. As far as we know, this case is the first survival patient after the longest cardiac assist in our country.

Acute Disease↗
PubMed1990

[Consideration of management of type B dissecting aneurysms of the thoracic aorta: clinical comparative study between surgical and medical treatments].

Between 1970 and 1989, 116 patients with type B dissecting aneurysms of the thoracic aorta were seen in our institution and affiliated hospitals. The patients were classified into 5 groups according to the acuity (acute vs chronic) and modes of therapy (surgical vs medical). Group I: 24 patients with acute B dissection were treated surgically during the acute stage. Group II: 21 patients with acute B dissection were initially treated with intensive medical therapy and followed by elective operation during the subacute stage. Group III: 22 patients with acute B dissection were treated medically. Group IV: 42 patients with chronic dissection were treated surgically. Group V: 7 patients with chronic B dissection were treated medically. The 5-year survival rates including early mortality were 70.5 +/- 9.4% for Group I, 88.9 +/- 7.5% for Group II, 68.3 +/- 11.2% for Group III, 64.6 +/- 8.4% for Group IV and 71.4 +/- 17.1% for Group V. The 5-year survival rates of Group II was significantly better than those of Group I, III and IV, respectively. The present data suggests that acute type B dissection without complications (bleeding, visceral or lower limbs ischemia) should be treated initially with intensive medical therapy and then followed by elective operation during the subacute stage, if the false lumen were not thrombosed.

Adult↗
PubMed1990

[Have the results of mitral valve replacement improved?].

The operative mortality following valvular surgery remains substantial for specific high risk groups despite recent improvement in surgical techniques, anesthetic managements, and postoperative care. To test the contention that the results of valvular surgery are better in recent years, we examined patients undergoing isolated or combined mitral valve replacement in an earlier era (1980-1984; n = 68) and a later era (1985-1989; n = 106). There were no significant differences concerning the clinical characteristics between an earlier era and a later era, although patients in an earlier era were more seriously in hemodynamics, and in a later era were older, a higher prevalence of reoperations and a combined tricuspid valve surgery. The operative mortality was 10.3% in an earlier era, 6.6% in a later era, and so it is not significantly improved in a recent 5 years, however the incidence of premature death (death within 30 days) except valve re-replacement was significantly improved. Using univariate multiple logistic model, the predictors for operative death after mitral valve replacement in an earlier era were advanced NYHA functional class, larger CTR, higher systolic pulmonary pressure and pulmonary capillary wedge pressure, associated preoperative organ dysfunction and heart lung machine time. In a later era, these were advanced NYHA functional class, higher right atrial mean pressure, associated preoperative organ dysfunction, valve re-replacement, heart lung machine time and aortic cross clamp time. Multivariate analysis including these significant factors could not demonstrated the most independent predictors of operative mortality after mitral valve replacement in both an earlier era and a later era.(ABSTRACT TRUNCATED AT 250 WORDS)

Female↗
PubMed1990

[Surgical treatment for a patient with respiratory failure due to annulo-aortic ectasia and aortic arch aneurysm].

It is not always easy to determine the causes of preoperative respiratory failure when either cardiac failure due to annuloaortic ectasia (AAE) or compression of the bronchus by aortic arch aneurysm are involved. A 64-year-old man was admitted to the emergency room of our hospital because of dyspnea and disturbance of consciousness. The findings of chest X-ray, UCG and CT scan on admission revealed AAE and aortic arch aneurysm, so we performed an emergency operation using Bentall's procedure. In spite of improvement of the cardiac failure after operation, hypercapnemia still remained, which was considered to be due to compression of the bronchus by the aortic arch aneurysm. Therefore, at the second stage, resection and replacement of the aortic arch aneurysm was performed with the aid of selective cerebral perfusion. After this operation, he could be weaned from the respirator.

Aorta, Thoracic↗
PubMed1990

[A case report of successful emergency re-AVR for structural failure of a Hall-Kaster prosthesis].

A rare case of Hall-Kaster prosthetic valve dysfunction was reported. The patient was admitted with acute cardiac failure. She had previously received aortic valve replacement (AVR) using 23A Hall-Kaster prosthesis. Prosthetic valve dysfunction was diagnosed by both cinefluoroscopy and echocardiography. Emergent re-AVR was carried out and dislodgement of the pivot was revealed. Postoperative course was uneventful. Reports of structural failure of the Hall-Kaster (Medtronic-Hall) prosthesis are extremely rare. To our knowledge, this is the first reported case of dislodgement of the disc from the pivot of the Hall-Kaster prosthesis.

Acute Disease↗
PubMed1990

Evolution and development of membrane components in erythroid precursor cells in newly-developed two phase culture system.

A selective two phase liquid culture system for human erythroid progenitors was established, utilizing mononuclear cells obtained from human peripheral blood. The culture was performed in the presence of PHA-leukocyte conditioned medium for 7 days as the first phase, and nonphagocytic cells were recultured under hypoxic culture conditions containing iron-saturated transferrin and erythropoietin. During the second phase of the culture, differentiation to orthochromatic erythroblasts was observed on day 4, and to denucleated cells on day 8 with 16.8 +/- 0.7 micrograms/10(6) cells of hemoglobin level, respectively. Flow cytometric analyses revealed that, on day 3, cells became type M-positive, and the expression of ABH increased gradually corresponding to the extent of erythroid maturation. Lewis antigens and P antigens were expressed at day 5. The system is beneficial for studies on human membrane disorders, because the erythroid progenitors in human peripheral blood were utilized and the reasonable number of erythroid cells (0.5-1.5 x 10(7] was obtained with good erythroid maturation, such as denucleated erythrocytes.

Antigens↗
PubMed1989

Right ventricular mechanical and energetic properties.

To formulate right ventricular (RV) mechanical and energetic properties in terms of the time-varying elastance model, Emax and the systolic pressure-volume area (PVA) of RV were measured in the excised cross-circulated heart preparation, while the left ventricle was beating unloaded. Emax of RV was constant, and independent of the RV volume, the stroke volume, the ejection velocity, and the pre-ejection period in the control contractile state. Enhancement of the contractile state with calcium increased Emax, and reduction of the contractile state with propranolol decreased Emax. The whole heart oxygen consumption (Vo2) was linearly regressed on PVA of RV, in both the control and the calcium-enhanced contractile state. Calcium elevated the regression line in a parallel manner. The slope of the regression line was (1.85 +/- 0.19) x 10(-5) ml O2/mmHg ml in the control state, and (1.57 +/- 0.44) in the calcium state. These slope values were similar to those in left ventricle (LV). We therefore conclude that mechanical and energetic properties of RV are similar to those of LV.

Animals↗
PubMed1989

[Gallium-67 imaging in patients with myocarditis in childhood and youth].

Gallium-67 (Ga-67) myocardial imaging was performed in 19 patients (1 month to 21 years of age) with proven or suspected myocarditis. The anterior images, 48 hrs after the intravenous administration of 0.5-2.0 mCi Ga-67 citrate, were analysed using a computer. Regions of interest were set on the heart, lungs and background, excluding the sternum and vertebrae. The uptake of Ga-67 was evaluated quantitatively by the ratio of the average count of the heart to the average count of the lung (H/L). When the H/L value was higher than 130% the cardiac uptake of Ga-67 was designated positive. Histological examination was performed in 11 patients who underwent right endomyocardial biopsy. The patients were categorized according to their clinical findings. Group 1 consisted of 11 patients with clinical symptoms of dilated cardiomyopathy, six of whom had arrhythmias or elevated serum CPK-MB levels (group Ia) in the acute stage of the disease, and the remaining five had neither (group Ib). Group 2 consisted of eight patients with dysrhythmias but without heart failure. Four had elevated serum CPK-MB levels (group IIa), but the remaining four did not (group IIb). All patients in the group Ia had positive Ga-67 uptakes, and three patients in the group Ib had negative uptakes. The H/L values were significantly higher in the group Ia than in the group Ib (p less than 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Doppler echocardiographic estimates of pressure gradients in various types of stenoses: usefulness and limitations].

UNLABELLED: In the present study, the accuracy of Doppler estimates of pressure gradients in various types of stenoses was clinically and experimentally evaluated. Fifty-seven patients, including 23 with ventricular septal defect, 15 with aortic or pulmonary valvular stenosis, four with infundibular stenosis, and five with supravalvular aortic or pulmonary stenosis were observed. The peak systolic pressure gradient (dP (C] was obtained at the time of catheterization in all patients. Before catheterization, the maximum velocity was measured by pulsed or continuous Doppler echocardiography and the estimated systolic pressure gradient according to Doppler (dP (D] was calculated by the simplified Bernoulli equation. The experimental model was designed to create pulsatile flow through a stenosis model. Nine different stenotic model types were used, including three orifice-like stenoses and six truncated cones with heights of 10 mm and 20 mm distal to the stenosis. The orifices in their stenoses were 3, 4 and 5 mm, respectively. Glycerin solution containing Sephadex with a viscosity similar to that of blood was used as the circulation medium. Its specific gravity was 1.16 g/cm3. In each stenotic model, the maximum velocity and instantaneous systolic peak pressure gradient were measured at various water flow rates. CLINICAL RESULTS: In patients with ventricular septal defect or valvular stenosis, dP (D) correlated very well to dP (C), with the regression equation, y = 0.87x + 2.79 (r = 0.92) or y = 0.96x + 1.02 (r = 0.99). In the other patients except for three with patent ductus arteriosus, dP (D) overestimated dP (C) by 11 to 71 mmHg, and their post-stenotic areas had gradually widened according to angiographic findings.(ABSTRACT TRUNCATED AT 250 WORDS)

Aortic Stenosis, Subvalvular↗
PubMed1989

[Clinical study on surgical treatment of aortic arch aneurysm using selective cerebral perfusion or hypothermic circulatory arrest].

To improve the surgical results of aneurysms of the transverse aortic arch, it is essential to select the optimal support technique to protect the cerebral ischemia during the aortic arch occlusion. In the four year period between 1983 and 1987, 21 consecutive patients had surgical correction of aneurysms of the transverse aortic arch at our institution. The causes of aneurysms were dissection (type A) in 16 patients and arteriosclerosis in 5 patients. Seven patients had emergency operation for frank or impending rupture. Two method for cerebral protection were employed during the period of arch exclusion. In Group I, 11 patients underwent selective cerebral perfusion both to innominate and left common carotid arteries via one roller pump at a rate of 600 ml/min (25 degrees C). The average cerebral perfusion time was 70.4 +/- 20.5 minutes. In Group II, 10 patients underwent deep hypothermia (15 degrees C to 20 degrees C) and total circulatory arrest to allow repair of the transverse aortic arch. The concomitant AVR was performed in two patients and CABG in one patient. The average cerebral arrest time was 35.2 +/- 3.4 minutes. Two out of 10 patients had additional cerebral perfusion because cerebral ischemic time exceeded over 45 minutes. There were three early deaths (14.3%) in this series. The causes of early death were bleeding in two patients and renal failure in one patient. There were no cerebral complications in both groups. The duration of extracorporeal bypass necessary for cooling and rewarming phase in Group II was longer than that in Group I.(ABSTRACT TRUNCATED AT 250 WORDS)

Aged↗
PubMed1989

[Total graft replacement of the thoracoabdominal aorta with reconstruction of visceral branches, intercostal and lumbar arteries in expanding chronic dissecting aneurysms of the thoracoabdominal aorta].

Four patients with expanding chronic dissecting thoracoabdominal aneurysm underwent total replacement of the thoracoabdominal aorta with reconstruction of all visceral branches, intercostal and lumbar arteries with the aid of femoro-femoral bypass. During aortic cross-clamping, selective celiac and both renal arteries perfusion was performed to prevent the organ ischemia. Somatosensory evoked potentials monitoring or spinal cord evoked potentials monitoring was also performed to detect the spinal cord ischemia. Surgical technique employed in this series was direct anastomosis of onlay patch graft to the normal true lumen from which visceral branches and intercostal and lumbar arteries arise. The celiac artery and left renal artery arise from the false lumen in some cases were reconstructed with graft interposition or direct anastomosis to an opening made in the onlay patch graft. All patients survived the operation, and are leading normal life late in the postoperative period except one who developed partial paraplegia. Total graft replacement of the thoracoabdominal aorta may be a valid technique for the treatment of expanding aneurysms of the dissecting thoracoabdominal aorta.

Adult↗