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Biomedical subjects

T Togo

Publications and source records attributed to T Togo.

At least 55 records · Page 3Linked to original sources
PubMed1990

[A new experimental model of pulmonary hypertension in dog using an adjustable pulmonary artery band].

In order to study pathogenesis, reversibility, and treatment of pulmonary hypertension in congenital heart disease, a new experimental model to induce pulmonary vascular diseases has been designed. Previous models by other investigators were anastomosis between a systemic artery and pulmonary artery of one lung lobe, and these could not provide constant induction of pulmonary vascular diseases. Furthermore the postoperative mortalities in their experiences were quite high and acute iatrogenic pathological changes such as bleeding, edema and emphysema developed in the pulmonary vasculature and parenchyma of the anastomosed lobe. Use of our adjustable pulmonary artery band has eliminated such unwanted complications. The surgical procedure includes an end-to-side anastomosis of the left main pulmonary artery to the descending thoracic aorta, and banding of the anastomosed pulmonary artery using the adjustable band. The band was gradually loosened by extrathoracic manipulation during three to four weeks observation after operation. This technique provided dogs to survive sufficiently long enough and with a high success rate, and to produce extremely advanced pulmonary vascular diseases. Of the twenty dogs operated such, eighteen survived the first postsurgical week and thirteen dogs developed hypertensive pulmonary vascular diseases. Development of the medial hypertrophy was evident at one week and gradually advanced. In eight weeks, intimal cellular proliferation (Grade 2 of the Heath & Edwards' classification) became apparent. In twelve weeks, the intimal proliferation became fibrous and acellular (Grade 3) and caused complete obstruction of the lumen of some muscular arteries. In twenty weeks specimen, typical plexiform lesions (Grade 4) and dilatation lesions (Grade 5) involved the small muscular arteries in the whole left lung.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

Detection of cardiac allograft rejection and myocyte necrosis by monoclonal antibody to cardiac myosin.

Indium 111-labeled monoclonal antibody to cardiac myosin was examined for efficacy in the detection of cardiac graft rejection and rejection-related myocyte necrosis. Heterotopic heart transplants were performed in isogenic and allogenic groups of rats (n = 56). At selected intervals posttransplant, uptake of injected antibody in the donor and native hearts was determined by gamma scintillation scanning. Indium uptake was compared to histologic results graded for the severity of rejection and the presence of myocyte necrosis. The donor heart uptake of labeled antibody was significantly greater in both moderate rejection and severe rejection than in lesser degrees of rejection (P = 0.05). The donor/native heart antibody uptake ratio (AUR) in both severe and moderate rejection were significantly different from no or mild rejection (P = 0.05). In pooled grafts without myocyte necrosis, both the absolute donor heart antibody uptake and the donor/native heart AUR were significantly greater in grafts with moderate or severe rejection than in those with no or mild rejection (P less than 0.001). Among grafts with moderate or severe rejection, those with myocyte necrosis had greater donor heart antibody uptakes and greater donor/native heart AUR than grafts without myocyte necrosis (P less than 0.001). The grade of rejection and the presence of histologic myocyte necrosis appear to be closely related but independent variables, both of which influence antibody uptake. It is concluded that monoclonal antibody to cardiac myosin may be a useful noninvasive tool that could distinguish moderate or severe rejection from lesser degrees of rejection and that could detect the presence of myocyte necrosis.

Animals↗
PubMed1989

[Growth of tracheal anastomoses in growing animals].

Growth of the trachea after complete transection and anastomoses was studied in four equal groups (N = 7) of young New Zealand white rabbits (mean weight 1.19 +/- 0.19 kg). The trachea was transected below the 5th cartilagenous ring and immediately anastomosed. Suture materials and sewing techniques used for comparison were continuous 6-0 polypropylene, interrupted 6-0 polypropylene, continuous 6-0 polydioxanone (PDS) or interrupted 6-0 PDS. The animals were electively sacrificed between 95 and 98 days after surgery. Mean body weight increased to 2.7 +/- 0.18 kg. Mean cross sectional area (CSA) of the trachea at sacrifice at the anastomosis (A) and an average of CSA 5 mm above and below the anastomosis (B) were compared. The ratios (A/B) of each groups were 0.52 (continuous polypropylene), 0.62 (interrupted polypropylene), 0.58 (continuous PDS) and 0.80 (interrupted PDS), respectively. One way of analysis of variance revealed that growth of the tracheal anastomoses in interrupted PDS was significantly better (p less than 0.005) than other combinations. It was concluded that growth of the trachea following complete transection and anastomosis in a growing animal was significantly better with absorbable suture material and interrupted suturing technique.

Anastomosis, Surgical↗
PubMed1989

[Outbreaks of asthma attacks and meteorological parameters--multivariate analysis].

The correlation between patient visits and meteorological parameters was analyzed among asthmatic children who visited the out-patient emergency clinic at the Teikyo University Hospital during the three years from 1984 to 1986. Data were analyzed with the method of multivariate analysis (quantification theory type II). The major factors affecting the frequency of visits were an air temperature at more than 15 degrees C, a relative humidity at more than 65%, a vapor pressure at more 1013 mb and a wind speed at less than 3.5 m/sec. Multivariate analysis of seven meteorological parameters, the four parameters shown above plus sea level pressure, cloud density and precipitation, revealed that discrimination ratios with the Lag 3, Lag 2, Lag 1 and Lag 0 values were 63.8%, 68.5%, 68.5% and 63.6%, respectively. These results indicate that asthma forecast is possible by the multivariate analysis of meteorological conditions.

Asthma↗
PubMed1989

[Experimental study of materials used for intra-atrial baffle for the Mustard operation].

An experimental model was developed to study the fate of prosthetic materials used for the construction of an intra-atrial baffle for the Mustard operation. Total atrial septa were replaced in sixteen puppies with autologous pericardium (n = 3), glutaraldehyde-preserved canine pericardium (n = 4), glutaraldehyde-preserved porcine pericardium (n = 3), EPTFE reinforced sheet (Gore-Tex sheet, n = 3) and EPTFE reinforced cardiovascular patch (Gore-Tex patch, n = 3). Septal replacement was performed under total circulatory arrest and surface induced deep hypothermia. All animals were sacrificed six months after the septal replacement. Pathological examination revealed that all septal grafts were well healed, completely covered by neoendothelium and had contracted to approximately 60% of their original size. There were no significant difference between groups. Histologic examination showed the good tissue adaptation of autologous pericardium and Gore-Tex patch materials. The thinnest layers of neoendothelium covered autologous pericardial baffle. Glutaraldehyde-preserved pericardium and Gore-Tex sheet did not adapt well to host atrial tissue. These materials were easily detached from their neoendothelial substrates. It was concluded that the autologous pericardium as well as a Gore-Tex patch may be superior to other prosthetic materials used for the construction of an intra-atrial baffle for the correction of transposition of the great arteries.

Animals↗
PubMed1988

A study of adenovirus gastroenteritis in the Tokyo area.

Probable serotypes of faecal adenoviruses 40, 41, 31, 2 and 1 were found in the Tokyo area by rapid DNA restriction endonuclease analyses directly of stool specimens or after primary culture in Graham 293 cells. Some variations were found in both adenoviruses 40 and 41 by this method.

Adenoviridae↗
PubMed1988

Experimental validation of Doppler echocardiographic measurement of volume flow through the stenotic aortic valve.

In aortic stenosis, evaluation of aortic valve area by the continuity equation assumes that the volume of flow through the stenotic valve can be measured accurately in the left ventricular outflow tract. To test the accuracy of Doppler volume-flow measurement proximal to a stenotic valve, we developed an open-chest canine model in which the native leaflets were sutured together to create variable degrees of acute aortic stenosis. Left ventricular and aortic pressures were measured with micromanometer-tipped catheters. Volume flow was controlled and varied by directing systemic venous return through a calibrated roller pump and back to the right atrium. Because transaortic volume flow will not equal roller pump output when there is coexisting aortic insufficiency (present in 67% of studies), transaortic flow was measured by electromagnetic flowmeter with the flow probe placed around the proximal descending thoracic aorta, just beyond the ligated arch vessels. In 12 adult, mongrel dogs (mean weight, 25 kg), the mean transaortic pressure gradient ranged from 2 to 74 mm Hg, and transaortic volume flow ranged from 0.9 to 3.2 l/min. In four dogs, electromagnetic flow that was measured distal to the valve was accurate compared with volume flow determined by timed collection of total aortic flow into a graduated cylinder (n = 24, r = 0.97, electromagnetic flow = 0.87 Direct +0.13 l/min). In eight subsequent dogs, electromagnetic flow was compared with transaortic cardiac output measured by Doppler echocardiography in the left ventricular outflow tract as circular cross-sectional area [pi(D/2)2] x left ventricular outflow tract velocity-time integral x heart rate.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1988

Cardiac transplantation without cardiopulmonary bypass: experimental model to study growth of the transplanted heart.

An experimental model using surface-induced (20 degrees C) deep hypothermia and total circulatory arrest instead of cardiopulmonary bypass was developed for the study of growth of the transplanted heart. Autotransplantation of the heart was performed in 42 young dogs weighing from 4.4 to 9.0 kg (mean, 6.9 kg). Time of ischemia ranged from 26.0 to 60 minutes (mean, 43.4 minutes). Return of satisfactory cardiac function occurred in all but one animal. An early high mortality rate was due primarily to pulmonary complications, but with modifications to the technique, long-term survival increased to 70%. Early deaths (5 days to 13 weeks) of five dogs during preliminary trials were due to pleural effusion (2), sepsis (1), endocarditis (1), and ascites (1). There have been 14 long-term survivors (range, 194 to 498 days; mean, 264 days). Long-term survivors appear well, are active, and show satisfactory growth. This experimental model eliminates the need for heparinization and reduces the potential for complications associated with cardiopulmonary bypass in the dog. It avoids cannulations that might impinge on anastomotic sites. This model appears to be suited for studying growth of the transplanted heart.

Animals↗