Yukio Wada

Remodeling of Cell-Cell and Cell–Extracellular Matrix Interactions at the Border Zone of Rat Myocardial Infarcts

At the border zone of myocardial infarcts, surviving cardiomyocytes achieve drastic remodeling of cell-cell and cell-extracellular matrix interactions. Spatiotemporal changes in these interactions are likely related to each other and possibly have significant impact on cardiac function. To elucidate the changes, we conducted experimental infarction in rats and performed 3-dimensional analysis of the localization of gap junctions (connexin43), desmosomes (desmoplakin), adherens junctions (cadherin), and integrins (beta(1)-integrin) by immunoconfocal microscopy. After myocardial infarction, changes in the distribution of gap junctions, desmosomes, and adherens junctions showed a similar but nonidentical tendency. In the early phase, gap junctions almost disappeared at stumps (longitudinal edges of cardiomyocytes facing the infarct), and, although desmosomes and adherens junctions decreased, they still remained. In the healing phase, at stumps, connexin43, desmoplakin, and cadherin were closely associated between multiple cell processes originating from a single cardiomyocyte. Electron microscopy confirmed the presence of junctional complexes between the cell processes. beta(1)-Integrin at the cell process increased during the formation of papillary myotendinous junction-like structures. Abnormal localization of connexin43 was often accompanied by desmoplakin and cadherin on lateral surfaces of surviving cardiomyocytes. These findings suggested that remodeling of gap junction distribution was closely linked to changes in desmosomes and adherens junctions and that temporary formation of intracellular junctional complexes was an element of the remodeling of cell-cell and cell-extracellular matrix interactions after myocardial infarction. Moreover, the remodeling of the intercalated disk region at the myocardial interface with area of scar tissues was associated with the acquisition of extracellular matrix and beta(1)-integrin.

Histologic modification by cryopreservation in rat aortic allografts

Histologic changes after the cryopreserved rat aortic transplantation were studied, and the influences of the cryopreservation and of the allografting on the histology were examined. Four groups of Brown Norway (RT1n) and Lewis rats (RT1(1)) were used (n = 4 at each examined period in each group): the cryopreservation-allograft group (from Brown Norway to Lewis with cryopreservation), the cryopreservation-isograft group (from Lewis to Lewis with cryopreservation), the fresh allograft group (from Brown Norway to Lewis without cryopreservation), and the fresh isograft group (from Lewis to Lewis without cryopreservation). The graft was harvested from a descending thoracic aorta of a donor rat, implanted to an infrarenal abdominal aorta of a recipient rat, and extracted at 10 days, 1, 3, 6, and 12 months after the operation. The intimal thickening, cellular loss in the media, and cellular infiltration in the adventitia were observed, which were the same phenomena seen in chronic rejection of human organ allografts. Although the degree of intimal thickening and cellular loss in the media were higher in the cryopreserved groups than in the fresh groups, the cryopreservation procedure suppressed cellular infiltration in the adventitia after allotransplantation. The immunologic attack against the graft might be diminished by cryopreservation.

Comparison of hemodynamic data before and after corrective surgery for Down's syndrome and ventricular septal defect

SummaryLeft ventricular function and the extent of pulmonary vascular disease were studied in 18 children with Downs syndrome and 20 children without Downs syndrome who underwent corrective surgery for ventricular septal defect (VSD) and severe pulmonary hypertension. This study was conducted between 1985 and 1993. All patients underwent routine cardiac catheterization preoperatively and postoperatively (mean, 11.4 months after surgery). Left ventricular function was estimated using cineangiographic levograms. In both groups, the pulmonary-to-systemic arterial pressure ratio (Pp/Ps) and pulmonary vascular resistance (PVR) were significantly lower after surgery (P < 0.05). Postoperative improvement was more remarkable in the non-Down group (P < 0.05). Left ventricular end-diastolic volume (percent of normal) (LVEDV%N) was significantly lower after surgery in both groups (P < 0.01). The left ventricular stroke work-to-end-diastolic volume ratio (LVSW/EDV) was significantly higher after surgery in the non-Down group only (P < 0.01). Postoperative left ventricular ejection fraction (LVEF) was significantly lower in the Down group than in the non-Down group (P < 0.01). Some degree of irreversible pulmonary vascular disease was present after repair of VSD in patients with Downs syndrome. In the Down group, there were no significant changes in left ventricular function after surgery, despite the relief of volume overload. These results suggest that early diagnosis and surgical repair are key elements in the management of patients with Downs syndrome and VSD.

Pulmonary reconstruction in the ross procedure: Combined autologous aortic and polytetrafluoroethylene valve

Aortic root replacement with the pulmonary autograft is a valuable technique especially in children with the left ventricular outflow obstruction or a dilated aortic anulus, because it avoids use of a prosthetic valve and anticoagulation therapy. However, problems with durability and growth potential of the pulmonary autografts in the aortic position have been reported. 1 The best material for reconstructing the right ventricular outflow tract (RVOT) also remains controversial. We describe a technique performed concomitantly with the Ross procedure, in which the RVOT was reconstructed with a tricuspid valve made of the autologous aortic noncoronary cusp and a bicuspid valve made of expanded polytetrafluoroethylene (ePTFE). The patient was an 8-year-old girl, weighing 23 kg, in New York Heart Association functional class II. The echocardiogram showed that the aortic valve had 3 cusps: a large mobile noncoronary cusp and small restrictive right and left cusps. All commissures were fused. Cardiac catheterization and cineangiocardiogram showed a pressure gradient of 80 mm Hg between the left ventricle and ascending aorta and moderate aortic regurgitation. The aortic annular diameter was 19 mm (144% of normal value); the pulmonary annular diameter was 14 mm (106% of the normal aortic annular value). Preoperatively, 400 mL of autologous whole blood was drawn and stored for postoperative transfusions, and recombinant epoetin alfa (Kirin Permacology, Tokyo, Japan) was administered. Through a median sternotomy, moderate hypothermic cardiopulmonary bypass (28°C) was established. With the heart beating, the anterior and lateral aspects of the pulmonary artery were excised from the RVOT. The posterior aspect was excised after aortic crossclamping and administration of cold crystalloid cardioplegic solution, taking care to avoid the septal perforator coronary artery. The excised pulmonary autograft was preserved in cold saline solution. The ascending aorta was transected 5 mm above the sinotubular junction. The left and right coronary ostia were detached along the adjacent aortic wall. The right and left coronary cusps were hypoplastic and tightly adherent to a subvalvular fibrous ridge; neither of the cusps was mobile. The free edge of the noncoronary cusp was slightly hypertrophied but sufficiently mobile. This cusp was harvested along with the adjacent aortic wall. The right side of the aortic fibrous ring of the noncoronary cusp was preserved to avoid injury to the atrioventricular conduct

Transposition of the great arteries with anomalous origin of the left coronary artery from the pulmonary artery

We describe an extremely rare case of successful arterial switch operation for an infantile complete transposition of the great arteries associated with ventricular septal defect and anomalous origin of the left coronary artery from the pulmonary artery in which the left main coronary artery arose from the posterior sinus of the pulmonary artery and the right coronary artery and an accessory branch arose from the aorta.

Repair of partial anomalous pulmonary venous connection with a minimal atriotomy

We present an alternative surgical technique for the repair of a partial anomalous pulmonary venous connection to the higher segment of the superior vena cava. Although the atriotomy is limited in this technique, a sufficiently large systemic venous chamber overlapping to the outside of the superior vena cava can be created.

Successful correction of a Collett Edwards type II truncus arteriosus after bilateral pulmonary artery banding--a case report.

A case of a 4 year old girl who underwent successful correction of a Collett Edwards type II truncus arteriosus following bilateral pulmonary artery banding is reported herein. The diagnosis of Collett Edwards type II truncus arteriosus was made when she was 5 months of age, after which the bilateral pulmonary artery banding was performed. This proved very effective and enabled elective radial surgery to be done. The radical operation was performed safely by a modified version of Rastelli’s procedure. The patient had an uneventful recovery and is now well with no symptoms one year following her operation.

Oblique plication for repair of the atrialized ventricle and tricuspid incompetence of Ebstein’s anomaly

An 8-year-old girl who weighed 42 kg presented Ebsteins anomaly with severe tricuspid incompetence, and mild systemic cyanosis during exercise. A new reconstructive procedure for this complex anomaly was used. Oblique transference of the displaced posterior leaflet was performed, which resulted in plication of the atrialized ventricle and reduction in the tricuspid annular diameter. This procedure requires neither detachment nor closure of the tricuspid valve.

Surgical palliation of cardiac malformations associated with right isomerism.

Between 1985 and 1993, palliative surgery was performed on 13 pediatric patients who had complex cardiovascular anomalies associated with right isomerism. The patients included two neonates, ten infants, and one child who were divided into two groups according to whether or not a total anomalous pulmonary venous connection (TAPVC) was present. Group 1 consisted of six patients with TAPVC and group 2 consisted of seven patients without TAPVC. In group 1, the surgical procedures involved TAPVC repair alone in two patients, combined TAPVC repair with a modified Blalock-Taussig shunt in two, combined TAPVC repair with pulmonary artery banding in one, and a modified Blalock-Taussig shunt alone in one. There were five hospital deaths and one late death in this group: pulmonary venous obstruction in two patients, perioperative myocardial failure in the two neonates, and congestive heart failure caused by increased pulmonary blood flow in two patients. In group 2, all the patients underwent systemic-pulmonary artery shunts, and there was one hospital death and three late deaths, the causes of which were unknown in two patients, and shunt failure and pneumonia in one patient each. These results suggest that surgical palliation for right isomerism produces poor results in young infants with obstructed TAPVC. Thus, we conclude that TAPVC repair should be performed without delay if pulmonary venous obstruction has been diagnosed clinically. Resolving pulmonary venous obstruction without cardiopulmonary bypass (CPB) may be preferable for infants, considering their difficult management. The systemic-pulmonary artery shunt should be of the low-calibrated type, especially if common atrioventricular valve regurgitation exists. If infants survive the surgery, they must be carefully followed up for a long period due to the risk of sudden death or infection.

A case of Successfully Operated Pelvic Arteriovenous Malformation.

動静脈奇形 (AVM) は四肢や脳, 肺などに発症することが多 く骨盤内のものは少ない. 今回われわれ は, そのような骨盤内AVMの 一例に対 して根治せしめたので報告する. 症例は59歳 女性で, 主訴は 右下腹部腫瘤である. 骨盤部CTと 血管造影で異常血管瘤を伴うAVMと 診断した. 手術は術前より 診断しえた feeding artery である右内腸骨動脈と右腰動脈および右尿管動脈を結紮し, 右腎動脈から のAVMと 瘤を摘出した. 術後の血管造影では, 右内腸骨動脈末梢の正常血管は左側からの側副血行 路により造影されたが, AVMは 完全に消失していた. 近年AVMに 対する治療法としてカテーテル による塞栓術が頻用されているが, 本症例のように流出系に異常血管瘤を伴う場合には, 塞栓術は危 険を伴い, 不確実である. このような症例には feeding artery を結紮し瘤を切除することが, より確 実で安全であり, 今回のような外科的摘出術が第一選択になると思われる. 日心外会誌23巻2号: 125-128 (1994)