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Biomedical subjects

S Nitta

Publications and source records attributed to S Nitta.

At least 163 records · Page 9Linked to original sources
PubMed1991

[A case of giant cell myocarditis associated with a progressive disturbance in the conduction system].

A 73 year old male patient with a history of pulmonary tuberculosis was admitted to our department because of dyspnea and abdominal pain. The chest X-ray film on admission showed bilateral lung congestion. The ECG showed atrial fibrillation, left axis deviation and incomplete right bundle branch block. Five days after admission, the ECG changed into sinus rhythm and complete right bundle branch block. Eight days after admission, the patient complained of chest pain and the ECG showed ST elevation in II, III, aVF, reciprocal ST depression in V, and complete A-V block with junctional rhythm. Emergency coronary angiography revealed no significant stenosis. Echocardiography showed reduced contraction of the inferior wall and diffuse granular echoes in the myocardium. Light microscopic study revealed fibrosis, infiltration of eosinophils and histiocytes, degenerated myocardium and multinucleated giant cells. Some of the giant cells were morphologically similar to myocardium, so the myocardium might be a place of immunological reaction.

Aged↗
PubMed1990

[A two-year-old child with tracheal stenosis due to tracheostomy treated by end-to-end anastomosis of the trachea].

Successful operation performed on a 2-year-old boy with tracheal stenosis due to long-term intubation was reported. He was admitted to our department 1 year after a neurosurgical operation. Endoscopically, destruction of cartilage rings was observed just above the site of tracheostomy, and the tracheal wall was collapsed without a help of tracheal tube. Reconstruction of the trachea by circumferential resection and end-to-end anastomosis was done. During the operation, the patient was uniformly ventilated by tracheal tube through nasal intubation. After the operation, tracheal intubation was continued for 7 days, and anterior fixation of neck for 8 days. The postoperative course was uneventful and the patient remains asymptomatic 8 months after operation.

Anastomosis, Surgical↗
PubMed1990

[Correlation between slopes of pulmonary blood flow-driving pressure curve and routine pulmonary function].

In 91 preoperative cases of lung cancer, an attempt was made to correlate the slopes of pulmonary blood flow-driving pressure curve (delta DP/delta CI), as constructed from unilateral pulmonary arterial occlusion (UPAO) test values and pulmonary blood flow fraction values as measured by scintigraphy, with total pulmonary vascular resistance index (TPVRI) and pulmonary vascular resistance index (PVRI) and routine pulmonary function. FVC and FEV per unit body surface (BSA) were found to correlate, to same degree, with delta DP/delta CI, TPVRI and PVRI (p less than 0.05). delta DP/delta CI correlated significantly with FRC/BSA, whereas TPVRI and PVRI did not. 3) The inverse of the cardiac index (1/cardiac index) was shown to significantly correlate with TPVRI and PVRI (r = 0.64, 0.48), but poorly with delta DP/delta CI (r = 0.32). These results suggest that delta DP/delta CI might possibly provide a more useful quantitative index for the pulmonary vascular bed than TPVRI and PVRI.

Adult↗
PubMed1990

[A case report of coronary artery bypass surgery (3-SVG) in 80-year-old woman with acute respiratory failure].

A successful operation for a patient of unstable angina with hypoxia is reported. A 80-year-old woman was admitted with severe chest oppression. The selective coronary angiogram revealed 3-vessel disease. Symptoms were uncontrolled by medical therapy. Aorto-coronary bypass surgery (with 3-saphenous vein grafts) was followed by excellent post-operative course. The patient has been asymptomatic for more than 1 year after operation.

Acute Disease↗
PubMed1990

Effect of left ventricular assistance on sympathetic tone.

To determine the effect of left ventricular assist device (LVAD) pumping on sympathetic tone, renal sympathetic nerve activity (RSNA) was detected in acute animal experiments. Our TH-7B pneumatically driven, sac-type ventricular assist device was used in 7 adult mongrel dogs. RSNA was detected by the use of bipolar electrodes attached to the left renal sympathetic nerve. RSNA was amplified and integrated by use of an R-C integrator circuit. The area of the integrated nerve discharge per unit time was calculated in the computer system and expressed as RSNA per unit time. During LVAD pumping, RSNA decreased with increase in blood pressure, with an increase in pulmonary artery flow, and with a decrease in left atrial pressure. These data suggest that LVAD has an effect on the sympathetic nervous system which is mediated by the aortic and cardiopulmonary baroreflex system.

Animals↗
PubMed1990

Micro-pressure sensor for continuous monitoring of a ventricular assist device.

We have been involved in the development of a clinical ventricular assist device (VAD) system. Here, we report our investigation of in vitro and in vivo stability and sensibility of pressure microsensors. The sensors were mounted in the in-flow and out-flow cannulae wall to measure the left atrial and aortic pressures during VAD pumping. The pressure sensitive surface of the piezoresistive effect absolute pressure sensor was coated with a thrombo-resistant polymer, as was the inner surface of the cannulae of the VAD. In the in vitro and chronic animal experiments which were of more than a month duration, reliable stability and sensitivity, without any thrombus formation on the blood contacting surface of the sensors, and high sensitivity were observed. After chronic experiments, the sensitivity of sensors was reevaluated in the mock circulatory system as compared to reference values. The relationship between the output of the micro-sensors and the reference value was linear and correlated well.

Animals↗
PubMed1990

[A case of mitral regurgitation caused by necrosis and total rupture of the papillary muscle].

Mitral regurgitation (MR) caused by total rupture of the papillary muscle has so ominous prognosis that it is treated by surgery exceedingly rarely. We recently experienced a case of MR caused by total rupture of the posterior papillary muscle that had presumably occurred after myocardial infarction. The patient was a 52-year-old male who was admitted to a hospital with liver dysfunction where he was noticed for the first time of his having cardiac murmurs and was diagnosed as having MR on the basis of echocardiography. With this diagnosis he was transferred to our department. Examination on admission revealed the patient to have an NYHA class III mitral incompetence with ECG evidence of old posteroinferior myocardial infarction. Cardiac catheterization demonstrated total occlusion of the segment 1 of the right coronary artery and MR, Sellers III. Abnormal echoes were noted in the left ventricle that moved almost synchronously with the posterior leaflet of the mitral valve, a finding leading to a suspected diagnosis of rupture of the posterior papillary muscle or chordae tendineae. Intraoperative findings were confirmative of total rupture of the posterior papillary muscle and mitral valve replacement was performed using a SJM prosthetic valve. Histological examination of the ruptured muscle revealed presence of necrosis, but no other specific inflammatory changes. Documented cases of surgically treated total papillary muscle rupture are quite limited in number, the present case being the 4th to be reported in Japan.

Heart Rupture↗
PubMed1990

[CT findings of the benign tracheobronchial lesions with calcification].

In the benign tracheobronchial lesions with calcification, tracheobronchopathia osteochondroplastica, relapsing polychondritis and tracheobronchial amyloidosis were considered. CT demonstrated small nodules with calcifications at the trachea with or without deformity of tracheal wall in the case of tracheobronchopathia osteochondroplastica, swelling of tracheal cartilage with diffuse and multiple calcifications in the case of relapsing polychondritis and calcifications in the deep parts of tracheobronchial amyloid nodules. CT findings were able to differentiate those benign lesions. High-resolution CT is more useful in the distribution of abnormal calcification of these diseases.

Aged↗
PubMed1989

[The use of direct current in the local destruction of cancer tissues].

Two platinum electrodes were inserted into malignant cancer tissue. One electrode was positive or anode, and the other was negative or cathode. Five to thirty milliamperes were employed between two electrodes. The tissue impedance was initially 600 ohms and decreased to 300 ohms in 30 minutes following the start. Marked acidosis was obtained around the anode, while strong alkalosis was created around the cathode. Cancer tissues of 2cm in diameter around the electrode became necrotic in 60 min. This principle was applied for the local destruction of cancer tissues. Repeated use of direct current seemed to be effective in decreasing the cancer volume around electrodes. For more complete destruction of the cancer tissues, bleomycin was injected intravenously in experimental animals. Since the agent was positively charged, it was easily drawn toward the negative electrode. Direct current was applied following the bleomycin injection, and animal tissues around electrodes were examined. The drug was found to accumulate around the cathode in 6 out of eleven cases. The use of direct current might be helpful in accumulating anti-cancer drugs in malignant tissue.

Adult↗
PubMed1989

[Induction of pulmonary edema in rat with pulmonary artery air embolization and inhibitory effects of dilazep hydrochloride].

Inducing pulmonary edema in rat, air bubbles the diameter of which was about 0.3 mm were continuously infused into the right atrium through a catheter at the rate of 2.8 ml/kg/hr during 0.5, 1 and 2 hours, under controlled ventilation (tidal volume of 9 ml/kg and respiratory rate of 80/min) with 1% halothane in room air. Saline or Dilazep hydrochloride solution was simultaneously infused into the right atrium via another catheter. Pulmonary edema was evaluated by the measurement of the ratio of extravascular water weight of lung (g) to blood-free dry lung weight (g) (EVWW) using the gravimetric method and with histologic studies using the rapid freezing method. In control rats, which were sacrificed immediately after induction of anesthesia, the EVWW was 3.114 +/- 0.121 g/g blood-free dry lung (mean +/- 1 S.D. n = 8). In baseline experiments (2 hours ventilation and saline infusion without air embolization), the EVWW was 3.291 +/- 0.081 (n = 4). In air embolization groups with 2 hours saline infusion, EVWW were 3.756 +/- 0.170 (n = 4), 3.722 +/- 0.170 (n = 4) and 3.731 +/- 0.245 (n = 5) in 0.5, 1 and 2 hours infusion groups, respectively. Regardless of emboli infusion time perivascular cuffs and peribronchial cuffs were revealed in the 2 hour saline infusion groups. In the experiment in which the animals were sacrificed immediately after one hour infusion of air bubbles, there was no evidence of pulmonary edema and the EVWW of 3.060 +/- 0.092 (n = 4) in this group control and baseline were not significantly different.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1989

[The effect of bilateral vagal blockade on respiration].

Although respiratory regulation has been extensively studied so far, the relation between the vagal nerves and respiratory reflex in man is still open to controversy. This paper describes the effect of bilateral vagal blockade on respiration. 1) Dyspnea due to unilateral bronchial occlusion. This type of dyspnea is caused by extreme depression of the intrabronchial pressure on the occluded side and is accompanied by a rapid increase in respiratory rate and a rapid decrease in tidal volume. This type of dyspnea is relieved by blockade of the ipsilateral cervical vagal nerve. 2) Animal experiments on bilateral lung transplantation, heart-lung transplantation and bilateral cervical vagal blockade. The respiratory changes induced by CO2 inhalation, low O2 inhalation, respiratory stimulant. Loss of blood or fever stimulation in the manipulated dogs were compared with those in normal controls. CO2 inhalation alone produced differences in the respiratory rates and tidal volumes between the two groups. The tidal volume increase under CO2 inhalation was suppressed by the inflation reflex but other afferent vagal nerves seemed to be closely associated with the increased respiratory rate. 3) Vagal nerve reflex in humans. Blockade of the bilateral cervical vagal nerves in an awake state resulted in irregular PETCO2 in cases that had been stable and sometimes produced a pattern of Cheyne-Stokes respiration. Inhalation of 5% CO2 restored the regular rhythm of respiration and enhanced the response to CO2. When subjected to bilateral vagal blockade in an awake state, the patient expressed an unbearbly uneasy dyspneic sensation as if he were pulled into a bottomless abyss. This was demonstrated by the unstable FRC level.

Animals↗
PubMed1989

[A case of aortitis syndrome with anastomoses from left coronary artery to bronchial artery].

We reported a case of aortitis syndrome with about 10-year course from onset. The patient was a 44-year old female suffering from a cardiac failure. The angiogram revealed presence of aortic regurgitation, The angiogram revealed presence of aortic regurgitation, pulmonary vascular lesions, anastomosis from left coronary artery to bronchial artery and hypervascularity of bronchial artery. We considered the anastomosis from left coronary artery to bronchial artery as a collateral blood flow for the ischemic lesions of the lung. We abandoned aortic valve replacement because of the severe pulmonary vascular lesions and of the pulmonary dysfunction.

Adult↗
PubMed1989

[Synthesis and evaluation of the adaptive control system for the ventricular assist device by using the circulatory system simulator].

An on-line digital simulator using microcomputer system was developed to mimic the hemodynamic behavior of the human circulatory system under ventricular assist device (VAD) pumping. This simulator could calculate the response to the variation of the cardiac function or the driving mode of VAD in the real-time fashion. This simulator was used as the mock controlled object to evaluate and improve the algorithm of an adaptive controller of the drive unit for VAD. The adaptive one-step ahead controller was introduced as the precompensator for the PI-controller, which decides the outflow volume from VAD in order to follow up the reference flow value by changing the systolic duration. It was confirmed that the proposed adaptive control system improved the response speed of the VAD driving system automatically according to the variation of the controlled object.

Algorithms↗
PubMed1989

[An adaptive control system of the ventricular assist device with the functions of measurement and analysis].

A personal computer based digital control system for driving the ventricular assist device (VAD) has been developed. Adaptive control, monitoring and analyzing functions are integrated into a software of the personal computer in this system. These functions can operate in parallel with one another because of the multi-interrupt processing used in the software. The system enables the operator to analyze the hemodynamic behavior of the circulatory system simultaneously with VAD pumping and to make on-line use of the result of the analysis in order to improve the driving condition of VAD.

Heart-Assist Devices↗
PubMed1988

Effect of vagus nerve cooling on hypercapnic and hypoxic ventilatory responses in anesthetized dogs.

We studied ventilatory responses under hypercapnic and hypoxic conditions in 18 lightly anesthetized dogs, using a vagus nerve cooling technique. One side of the cervical vagosympathetic trunks of dogs were previously severed, and a copper cooling probe was attached to the other side. When the cervical nerve was cooled below 7 degrees C, Hering-Breuer inflation reflex ceased. We found that when the vagus nerve was not cooled or cooled up to 7 degrees C, the respiratory frequency increased significantly in relation to hypercapnic gas inhalation. However, the increment of respiratory frequency was reduced by bilateral cervical vagotomy. On the other hand, the respiratory frequency in response to hypoxia increased significantly, even when bilateral vagotomy was done. The increment of the tidal volume in response to hypercapnic gas inhalation was reduced by the Hering-Breuer inflation reflex. We found that the effect of the vagus nerve on respiratory regulation was different between hypercapnic and hypoxic gas inhalation.

Animals↗