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Biomedical subjects

M Kawada

Publications and source records attributed to M Kawada.

At least 127 records · Page 7Linked to original sources
PubMed1989

[A new valved conduit with commissures using a glutaraldehyde preserved equi pericardium].

We developed a new valved conduit with commissures using a glutaraldehyde preserved equine pericardium, and implanted this prosthesis between the right ventricle and the pulmonary artery in the dog to examined the movement of the valve. Our new prosthesis consists of a conduit and three leaflets. Each leaflet is sutured to the inner surface of the conduit to form a valve. The adjacent free edges of the leaflets are sutured together by placing a mattress stitch 2 mm from their attachment to the conduit so that the leaflets form commissures. These commissures are designed to facilitate prompt coaptation of the three leaflets in diastole. A radiopaque marker is anchored to the center of the free edge of each leaflet and to the outer surface of the conduit to investigate its movement. The movement of the radiopaque markers studied by cineangiography revealed good coaptation of three leaflets in diastole and their full opening in systole. These findings demonstrated that the valve in our prosthesis might function well to prevent regurgitation across it.

Animals↗
PubMed1989

[The results of surgical treatment of total anomalous pulmonary venous return in neonates].

By the time, the results of surgical treatment for total anomalous pulmonary venous return have been unsatisfactory. From 1981, we changed a surgical procedure fro Gersony-Malm procedure to the posterior approach method, and a surgical technique from the deep hypothermia and the circulatory arrest to the moderate hypothermia and the pump perfusion. Consequently, the results of surgical treatment was improved. From 1981 to 1987, 18 neonates with total anomalous pulmonary venous return underwent corrective operations in our institute. This diagnosis was decided by echocardiography without cardiac catheterization, because the preoperative status of these neonates were poor. Under the cardiopulmonary bypass, we performed the posterior approach method for type I and III, the cut-back method and Van Praagh procedure for II and IV without aortic clamping. According to the posterior approach method, the atrial septal defect was closed through the left atrial incision and the left atrium was anastomosed to the common pulmonary trunk during ventricular fibrillation. The incision was limited within the common pulmonary trunk or the vertical vein and was not extended into the pulmonary veins. According to cut-back method and Van Praagh procedure, the coronary sinus was closed internally so as to avoid the postoperative conduction disturbance. There were four hospital deaths (22.2%). The causes of deaths were pulmonary hypertension in two, low cardiac output in one, and intracranial bleeding in one. From the results of our institution, we concluded that the primary factors determining the outcome were the condition of the patients prior to repair and the severity of pulmonary hypertension.

Cardiopulmonary Bypass↗
PubMed1989

[Jatene procedure for the intermediate type between original Taussig-Bing malformation and posterior transposition of the great arteries: a case report].

A successful Jatene procedure (Lecompte modification) in a 8-month old boy with the intermediate type between the original Taussig-Bing and the posterior transposition of the great arteries (p-TGA) is described. The aorta was located posterior to the right of the pulmonary artery (PA) which overrode the interventricular septum. There was no fibrous continuity between aortic and atrioventricular valves. In the original Taussig-Bing, intraventricular rerouting is applicable because of malaligned infundibular septum. However, in our case which was similar to p-TGA, the infundibular septum extending anteriorly as far down as the anterior papillary muscle, was almost aligned to the interventricular septum, so that intraventricular rerouting is not applicable but arterial switch operation is preferable. Hence, the primary interventricular foramen was enlarged by the wedge resection and the secondary interventricular foramen was closed using pericardial patch through PA. The continuity of PA was reestablished anterior to the new aorta. The left half of distal orifice of PA was suture-closed to shift the site of anastomosis rightwards to avoid kinking and compression on the coronary arteries. Postoperative catheterization demonstrated no pressure gradient between left ventricle and aorta.

Aorta↗
PubMed1989

[Modified Fontan procedure on 106 cases: indication and surgical results].

Since 1974, we have performed modified Fontan procedure on 106 patients, ranging in ages from 1 to 32 years, consisting of 44 cases of tricuspid atresia (TA), 21 with univentricular heart (UVH) of right ventricular type, 18 with UVH of left ventricular type, for which ventricular partition was unfeasible, and 23 with various complex anomalies. Hospital mortality rates for TA and other complex anomalies were 11.4 and 11.3%, respectively. Surgical results have markedly improved recently. Since 1986, 50 cases underwent Fontan procedure with 3 hospital deaths (6.0%). Late death occurred in 4 cases in a mean follow-up period of 49 months. Regarding the indication for operation, majority of patients had 2 to 3 parameters which were out of 10 criteria for Fontan procedure. Regurgitation of atrioventricular valve was repaired by annuloplasty in 19 patients underwent Fontan procedure and 17 survived. Abnormal systemic venous connection was seen in 11 cases and all survived. Association of total anomalous pulmonary venous connection is still a difficult problem and 2 of 5 cases died. Fontan procedure was performed in 8 patients following palliative right ventricular outflow reconstruction for poor development of pulmonary artery and 7 survived. Cumulative mortality rate for the entire series was relatively well at 15.1%.

Adolescent↗
PubMed1987

Induction of epidermal mucous metaplasia by culture of recombinants of undifferentiated epidermis and retinol-treated dermis in a chemically defined medium.

Epidermal mucous metaplasia of cultured skin is known to be induced by excess retinol. Studies were made on whether retinol affects primarily the epidermis or the dermis during retinol-induced epidermal mucous metaplasia of 13-day-old chick embryonic skin in culture. When recombinants of 13-day-old normal epidermis and retinol-treated dermis were cultured for 7 days in chemically defined medium in the absence of retinol, hormones, and serum, they showed altered epidermal differentiation toward secretory epithelium (mucous metaplasia). Thus retinol acted primarily on dermal cells.

Animals↗
PubMed1987

Primary hemangiopericytoma of the heart associated with pseudoaneurysm of the pulmonary artery--a case report.

A thirty-three-year-old male with malignant hemangiopericytoma of the right ventricular outflow tract and the pulmonary artery associated with pseudoaneurysm formation at the latter is presented. Contrast computed tomography was helpful in diagnosing the pseudoaneurysm of the pulmonary artery. The positional change of the murmur, with a tumor plop caused by the pedunculated tumor of the right ventricular outflow tract, was detected.

Adult↗
PubMed1987

Effect of insulin on murine megakaryocytopoiesis in a liquid culture system.

To examine the influence of insulin on megakaryocytopoiesis, we tested its effect on murine bone marrow cultures in a liquid culture system. In the presence of pokeweed mitogen-stimulated spleen cell conditioned medium in culture, insulin markedly enhanced megakaryocyte colony formation and increased the number and size of free megakaryocytes seen after 7 days. Many of the cells in cultures with insulin, however, were classified as immature, since they had a basophilic cytoplasm, a low cytoplasmic/nuclear ratio and low acetylcholinesterase activity. It is suggested that insulin potentiates murine marrow megakaryocytopoiesis in vitro, but that this is not accompanied by differentiation of the cells from the immature to mature state.

Acetylcholinesterase↗
PubMed1987

[Malignant hemangiopericytoma of the right ventricular outflow tract and the pulmonary artery: a case report].

A case of malignant hemangiopericytoma of the right ventricular outflow tract and the pulmonary artery associated with formation of a pseudoaneurysm in the latter is presented. This 33 year-old man had a four month history of illness. From the surgical point of view, all non-invasive modalities including phonocardiography, M-mode and two-dimensional echocardiography, radionuclide angiocardiography and contrast computed tomography underestimated the extent of the tumor as compared with the selective cineangiographic estimation. Therefore, it was suggested that in some situations where surgery is contemplated, a combination of non-invasive methods and cineangiography is essential to obtain sufficient diagnostic information, although the introduction of catheters into the right-sided cardiac chambers containing a mass might be hazardous because of potentiality dislodging portions of a tumor or adherent thrombus. Concerning pericardial abnormalities, contrast computed tomography was the most sensitive and specific method among the diagnostic techniques used in this case.

Adult↗
PubMed1986

A new method of conduction system staining.

Visualization of the conduction bundle is advantageous in the prevention of surgical trauma to the conduction system during open-heart surgery. Because vital staining using an iodine starch complex has been known to result in tissue damage, we have evaluated the effects of iodine gas on the specialized conduction system. The conduction bundle was stained, well enough to be identified, with iodine tincture, with Lugol's solution, and with iodine gas. However, all these agents except for iodine gas caused marked electrophysiological changes. Similar changes occurred with the use of ethanol and of 10% potassium iodine solution, which are the solvents of iodine tincture and Lugol's solution, respectively. Microscopic examination showed that iodine tincture, Lugol's solution, and their solvents caused marked histological changes in the conduction tissue. However, no significant changes in the conduction tissue were noted from iodine gas spraying. Therefore, tissue damage caused by iodine tincture and Lugol's solution was thought to be due not to a reaction to the iodine starch complex itself, but to their solvents. In a long-term experimental study of 10 dogs, we found that iodine gas caused no electrophysiological disturbances or damage of microscopic tissue. Of the agents we tested, only iodine gas is free from harmful effects and can be used clinically.

Animals↗
PubMed1986

Cardiohemodynamic effects of nipradilol (K-351) in the dog: comparison with propranolol, nadolol and prazosin.

The cardiohemodynamic effects of nipradilol (K-351) were studied in comparison with those of propranolol, nadolol and prazosin in anesthetized, open-chest dogs. All drugs were administered intravenously. Nipradilol produced dose-dependent decreases in systemic blood pressure (BP), heart rate (HR), venous return (VR) and cardiac output (COP), but virtually no change in right atrial pressure (RAP). Propranolol decreased HR, tended to decrease VR and COP and increased RAP, but produced no change in systemic BP. Nadolol also decreased HR, VR and COP and increased RAP, but did not change systemic BP. Prazosin decreased systemic BP, VR and COP and tended to decrease RAP, but scarcely affected HR. After propranolol or nadolol, nipradilol failed to reduce HR, but still produced definite decreases in systemic BP, VR and COP and a slight decrease in RAP. After prazosin, nipradilol still produced decreases in systemic BP, HR, VR and COP. These results suggest that nipradilol decreases VR and COP mainly by increasing venous capacitance through direct venodilator action and in part by increasing resistance to VR through beta-adrenoceptor blockade. This effect also appears to be responsible for its hypotensive effect.

Adrenergic beta-Antagonists↗
PubMed1986

Temporal and spatial interactions between the carotid sinus and vagally mediated baroreflexes in dogs.

We investigated the temporal and spatial interactions between the carotid sinus and aortic arch baroreflex control of arterial pressure in 25 dogs anesthetized with pentobarbital sodium. The carotid sinus baroreceptor region was vascularly isolated to control the intracarotid sinus pressure. A hemorrhage catheter was inserted into the aortic arch. The systemic arterial pressure change after quick mild hemorrhage (2 ml/kg body weight within 1-2 s) was monitored. The open-loop gain of the vagally mediated baroreflex system was estimated from the mean arterial pressure response to the hemorrhage. Three protocols were employed to analyze the interactions. In the first protocol, we determined the effect of different levels of intracarotid sinus pressure on the open-loop gain of the vagally mediated baroreflex system. There was no significant effect. In the second protocol, the open-loop gain of the carotid sinus baroreflex system was determined after vagotomy. In the third protocol, the vagally mediated baroreflex system was activated by the hemorrhage without (spatial interaction) or with (temporal interaction) a delay after changing the intracarotid sinus pressure. The spatial interaction was facilitatory. A temporal interaction was found between the carotid sinus and vagally mediated baroreflex systems, when the delay was less than 30 s.

Animals↗