Shinsuke Masuda

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.

Vascular endothelial growth factor enhances vascularization in microporous small caliber polyurethane grafts.

Neoarterial regeneration in an implanted small caliber vascular prosthesis is complexly controlled by many structural and biologic factors, such as cytokines. The authors designed an artificial graft, which was prepared as follows. Segmented polyurethane tubular film (inner diameter, 1.5 mm; wall thickness, 100 μ; length, 20 mm), in which micropores (pore size, 100 μ) were fabricated by an excimer laser ablation technique, were coated with a mixed solution of photore-active gelatin and heparin with or without cytokines (vascular endothelial growth factor [VEGF]: 5 or 50 μg/ml, basic fibro-blast growth factor [bFGF]: 1 μg/ml). These coated grafts were irradiated by ultraviolet light, and were implanted in aortas of rats for 4 weeks; the VEGF (5 μg/ml) group, n = 6; the bFGF group, n = 6; the VEGF (5 μg/ml)/bFGF group, n = 11; the VEGF (50 μg/ml)/bFGF group, n = 5; and the control group, n = 9. Control grafts were treated without cytokines. Endothelial coverage was greater for the cytokine immobilized groups (50–60%) than for the control group (30%). At the midportion of the triple VEGF immobilized group, many capillaries were seen in the neoarterial intima, and in the micropores, although such capillaries were rarely observed in the bFGF and control groups. Thus, impregnation of VEGF in the gelatinous layer of grafts enhanced transanastomotic tissue ingrowth and transmural capillary ingrowth. ASAIO Journal 1997; 43:M330-M534.

Nine-year Experience of Recurrent Anastomotic Pseudoaneurysms after Thoracoabdominal Aneurysm Graft Replacement in a Patient with Behçet Disease

A 47 year-old woman with Behçet disease presented with back pain. Computed tomography showed an extent IV thoracoabdominal aneurysm. Graft replacement with reconstruction of all visceral arteries was performed. At five years postoperatively, anastomotic pseudoaneurysm of the left renal artery occurred, and it was reconstructed with an 8-mm graft. Two years after the second reconstruction, anastomotic pseudoaneurysms of the abdominal aorta developed. Y-shaped graft replacement was performed. There has been no recurrence for one year since the last operation. In situ graft reconstruction for recurrent pseudoaneurysms in a Behçet disease patient more than five years after graft replacement with reconstruction of all visceral arteries is rare.

A new double lumen balloon catheter for retrograde cerebral perfusion via jugular vein cannulation.

A new catheter for retrograde cerebral perfusion (RCP) was developed that can be used to deliver blood directly into the internal jugular vein (IJV) beyond the venous valves at the jugular-subclavian junction and prevent blood from draining into the lower half of the body. This catheter can be inserted into the IJV via a standard puncture technique by use of a 14 Fr sheath. The catheter shaft has two channels for balloon inflation and blood perfusion, respectively. A balloon for occlusion of drainage veins (superior vena cava and azygos vein) is installed at the catheter tip. Side holes, through which oxygenated cold blood is delivered into the IJV, are located 95 mm from the catheter tip. In a mock circulatory study, the pressure at the perfusion line (16–118 mmHg) increased with the increasing flow rate (0–400 ml/min). In clinical application, under circulatory arrest with profound hypothermia, inflation of the balloon effectively reduced blood drainage into the lower half of the body and, consequently, RCP was successfully performed (flow rate, 300–350 ml/min; pressure at the IJV, 15 mmHg). Because all of these procedures were controlled from outside the operative field, RCP by use of this catheter could be useful in distal arch replacement via left lateral thoracotomy. ASAIO Journal 1997; 43:M731-M735.

Early experience with combined use of two plant-based hemostatic agents.

Bleeding from anastomoses, which is more effectively controlled with topical hemostatic agents than with sutures, has been one of the major problems in cardiovascular surgery. We describe a novel hemostatic technique using microporous polysaccharide hemosphere (Arista; Medafor Inc, Minneapolis, MN) in conjunction with a patch of oxidized regenerated cellulose (Nu-Knit; Ethicon, Johnson & Johnson, Somerville, NJ). Both of them are plant-based products and eliminate the risk of animal-borne or human-borne contaminants and have bactericidal advantages.

A Novel Chest Packing Technique for Intractable Bleeding After Open Heart Surgical Procedures

Intractable bleeding after cardiac surgical procedures is a life-threatening complication. In most cases, the main bleeding site is present in the retrosternal space, not the pericardial space. Packing the chest may be a useful technique for achieving hemostasis. Herein, we describe a novel and effective procedure for the treatment of intractable bleeding in the retrosternal space using a sheet of oxidized regenerated cellulose and sponges after cardiac surgical procedures.

Pancreaticoduodenal artery aneurysm involving papilla of vater successfully treated with endovascular approach despite intraoperative rupture.

An 81-year-old woman presented with dizziness and nasal bleeding. Gastrointestinal fiberscopy (GIF) showed a pulsatile aneurysm in the duodenum, and that the orifice of the papilla of Vater was involved. Three-dimensional computed tomography imaging showed an unruptured aneurysm in the pancreatic duodenal arcade. The patient underwent an emergent endovascular embolization of the donor arteries using coils and gelatin sponge particles. She was discharged without any complications. This case was extremely rare because of the anatomic location of the unruptured pancreaticoduodenal artery aneurysm and the fact that it involved the papilla of Vater, was detected with GIF, and was successfully treated endovascularly.

Cardiac Xanthoma Originating From Primary Cardiac Lymphoma

A 67-year-old man presented with dyspnea, general fatigue, and leg edema. Echocardiography demonstrated a large pericardial effusion with a 5 cm × 3 cm, dense hetero-echogenic tumor in the right atrium. At the time of the operation, the tumor was composed of soft but tough, yellowish, smaller smooth processes, and fragile, reddish, bigger nodules. Pathologic examination revealed that the yellow processes were xanthoma and that the reddish nodules were B-cell lymphoma. This case strongly supports the theory that normolipemic xanthomatosis is a secondary event in the lymphoid tissue neoplasm.

Perforation of sinus Valsalva 10 years after repair of ventricular septal defect.

A 60-year-old woman who underwent ventricular septal defect (VSD) closure, mitral valve repair, and tricuspid annuloplasty 10 years earlier, presented with congestive heart failure. Her previous postoperative echocardiogram demonstrated a residual VSD leak and moderate mitral regurgitation. Transesophageal echocardiography (Figure 1) showed moderate mitral regurgitation, severe tricuspid regurgitation, a large atrial septal defect, and a fistulous communication from the sinus of Valsalva to the right ventricle, which was confirmed by multi-slice computed tomography (Figure 2). Surgery revealed a prolapsed right coronary cusp with a 3-mm perforation at the lower end of the prolapsed leaflet, adhering to the edge of the VSD patch. The fistula was closed with autologous right coronary valvular leaflet, and concomitant aortic and mitral valve replacement was performed with repeat tricuspid annuloplasty and patch closure of the atrial septal defect that was caused by dehiscence of the previous interatrial septum atriotomy.

Slime method: modified hemostatic technique of fibrin glue in major cardiothoracic surgery

Surgical bleeding from anastomoses due to systemic heparinization or prolonged extracorporeal circulation, which is more effectively controlled with topical hemostatic agents than with sutures, has been one of the major problems in cardiovascular surgery. We describe a novel hemostatic technique using fibrin glue. Briefly, the two components of fibrinogen and thrombin solutions are mixed and put over the bleeding point immediately after the glue has become a viscous gel. Within a minute of local compression, the glue sets well enough to stop the bleed.