Biomedical subjects

H Tsuboi

Publications and source records attributed to H Tsuboi.

At least 127 records · Page 7Linked to original sources

PubMed1989

Effect of reperfusion on the cardiac acetylcholine and norepinephrine contents in rat hearts.

The effects of ischemia, reperfusion and hypoxia on the cardiac acetylcholine, choline, norepinephrine and cyclic AMP contents were investigated in isolated, spontaneously beating rat hearts perfused under constant pressure (100 cm H2O) with Krebs-Henseleit solution gassed with 95% O2-5% CO2. Acetylcholine, choline and norepinephrine were determined by high performance liquid chromatography with electrochemical detection. Cyclic AMP was determined by radioimmunoassay. One min reperfusion following 15 min ischemia (termination of perfusion) caused a significant decrease in both cardiac acetylcholine (P less than 0.05) and norepinephrine (P less than 0.01) contents, but had no significant effect on the cardiac norepinephrine/acetylcholine content ratio, or choline or cyclic AMP content. By contrast, 16 min ischemia did not significantly affect the cardiac acetylcholine, norepinephrine, choline or cyclic AMP content. Also, 16 min hypoxia (perfusion with Krebs Henseleit solution gassed with 95% N2 5% CO2) decreased the cardiac norepinephrine content significantly (P less than 0.01) and norepinephrine/acetylcholine content ratio slightly but not significantly. However, hypoxia had no significant effect on the cardiac acetylcholine, choline or cyclic AMP content. Pre-treatment with 10 microns atropine sulfate prevented the decrease in the cardiac acetylcholine content caused by reperfusion but caused a significant depletion in the cardiac norepinephrine content in the control (P less than 0.01) and ischemia (P less than 0.05) groups and a significant decrease in the norepinephrine/acetylcholine content ratio in all three groups (all, P less than 0.05). Extending the reperfusion period to 5 and 10 min following 15 min ischemia also caused a significant decrease in both cardiac acetylcholine and norepinephrine contents compared with the control groups. However, no significant difference in these contents was found between 1 min reperfusion group and 5 or 10 min reperfusion group. Twenty or 25 min ischemia alone did not significantly affect these contents. These findings suggest that reperfusion disturbs both the sympathetic and parasympathetic nervous systems in the heart and that pre-treatment with atropine adversely affects the balance of the autonomic nervous system.

Acetylcholine↗

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

[Legionella dumoffii and Legionella pneumophila serogroup 5 isolated from 2 cases of fulminant pneumonia].

We encountered two cases of legionella pneumonia which ran a dramatic course and isolated Legionella dumoffii from one patient and Legionella pneumophila serogroup 5 from the other patient. The patient from whom L. dumoffii was isolated was a 59-year-old male with no basic disease. He presented chill, fever, coughing and other symptoms, starting on July 3, 1986, his disease was diagnosed as pneumonia at the clinic of his company. The patient was then introduced and admitted to our hospital. On admission chest radiography disclosed zonal pneumonia with an unclear border in the right superior lobe of the lung; a beta-lactam preparation was administered, but no effect was obtained and the lung lesion showed a rapid advance. From this condition, we suspected legionella pneumonia and changed the therapy to treatment with erythromycin and rifampicillin. Despite this, no improvement occurred and the patient died on the 26th hospital day. Colonies like Legionella colonies were separated from a total of seven specimens of biopsy aspirated matter from the airway and autopsy collected lung abscess and tracheal secretions, and the bacterium was identified L. dumoffii based on the biochemical and serological properties. In addition, the patient's serum was found to have an increased antibody titer against L. dumoffii. Based on these findings, the patient's disease was diagnosed as pneumonia as caused by L. dumoffii, a relatively rare bacterium as a member of the genus Legionella. The patient from whom Legionella pneumophila serogroup 5 was isolated was an 81-year-old man with basic diseases such as heart failure, anemia and hypothyroidism. He presented fever, general fatigue, anorexia and other symptoms, starting around June 2, 1987; pneumonia was suspected and the patient was urgently admitted to our hospital. The patient died of pneumonia of unknown cause on the second hospital day. To clarify the cause, autopsy was conducted; a large number of colonies like Legionella colonies were noted in the lung tissue. Identification test was then conducted and the bacterium was identified as L. pneumophila; we concluded that the patient's pneumonia had been caused by the identified bacterium L. pneumophila. The isolate was further subjected to slide agglutination test and identified as L. pneumophila serogroup 5.

Aged↗

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↗

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

[Levels of plasma cyclic AMP in cardiac surgery].

The actions of hormones such as catecholamines, vasopressin and growth hormones are mediated by a common intracellular second messenger, cyclic AMP (adenosine 3',5'-monophosphate). The effects of cardiac surgery on plasma cyclic AMP were studied in 32 adults patients with aorta-coronary bypass or with valvular disease. Blood specimens were obtained before operation, at the beginning and at the end of the cardiopulmonary bypass, 1, 3, 6, 9, 12, 24, 48, 72, 168 hours after surgery. The plasma cyclic AMP level during cardiac operation was elevated above the preoperative level. High levels of plasma cyclic AMP were found both in the aorta-coronary bypass and in the valvular disease immediately after the end of cardiopulmonary bypass. The plasma cyclic AMP level in patients undergoing aorta-coronary bypass with aortic clamping time more than 60 minutes was 38.6 +/- 11.7 pmol/ml, compared to 25.6 +/- 6.6 pmol/ml with aortic clamping time less than 60 minutes immediately after the end of cardiopulmonary bypass. In patients undergoing valve replacement and/or commissurotomy with aortic clamping time more than 60 minutes, the plasma cyclic AMP level immediately after the end of cardiopulmonary bypass was 113 +/- 63.3 pmol/ml, compared to 45.4 +/- 10.3 pmol/ml with aortic clamping time less than 60 minutes (p less than 0.01, Student's t test). During 24 hours after cardiac surgery, the plasma cyclic AMP concentration returned to normal range. It is considered that the plasma cyclic AMP level reflects the risk of cardiac surgery in response to homeostatic derangement.

Cardiac Surgical Procedures↗

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↗

PubMed1987

Acetylcholine and norepinephrine concentrations in the heart of spontaneously hypertensive rats: a parasympathetic role in hypertension.

To determine the role of the parasympathetic system in the development of essential hypertension, the concentrations of acetylcholine (ACh) as a parasympathetic marker and norepinephrine (NE) as a sympathetic marker were measured simultaneously in the heart of spontaneously hypertensive rats (SHR) at 4, 10 and 27 weeks of age, and in age-matched control Wistar-Kyoto rats (WKY). ACh was measured using a highly sensitive and specific high performance liquid chromatography-electrochemical detection (HPLC-ECD) attached to a newly developed immobilized fixed enzyme column system. NE was measured by conventional HPLC-ECD. The ACh concentration decreased in the order right atrium (RA) greater than left atrium (LA) greater than right ventricle (RV) greater than interventricular septum (IVS) greater than left ventricle (LV) in both SHR and WKY of all age groups, and NE showed an almost identical pattern. The concentration of ACh tended to increase and that of NE to decrease with age in both strains. The concentrations of ACh in the heart were significantly different in the two strains, with the levels being consistently higher in the SHR strain regardless of age, although differences were most significant at 10 weeks. The mean concentrations of NE were higher in SHR than in WKY, but the differences between the two strains were significant only in the RV and IVS. The functional meanings of a given tissue concentration of a neurotransmitter are still controversial. However, the increase in SHR heart ACh concentration, in parallel with the development of hypertension, may reflect the augmented parasympathetic activity counteracting or compensating for the augmented sympathetic drive in the early stage of hypertension.

Acetylcholine↗

PubMed1987