Yukio Umeda

Dynamic changes in the mobility of LAT in aggregated lipid rafts upon T cell activation

Lipid rafts are known to aggregate in response to various stimuli. By way of raft aggregation after stimulation, signaling molecules in rafts accumulate and interact so that the signal received at a given membrane receptor is amplified efficiently from the site of aggregation. To elucidate the process of lipid raft aggregation during T cell activation, we analyzed the dynamic changes of a raft-associated protein, linker for activation of T cells (LAT), on T cell receptor stimulation using LAT fused to GFP (LAT-GFP). When transfectants expressing LAT-GFP were stimulated with anti-CD3–coated beads, LAT-GFP aggregated and formed patches at the area of bead contact. Photobleaching experiments using live cells revealed that LAT-GFP in patches was markedly less mobile than that in nonpatched regions. The decreased mobility in patches was dependent on raft organization supported by membrane cholesterol and signaling molecule binding sites, especially the phospholipase Cγ1 binding site in the cytoplasmic domain of LAT. Thus, although LAT normally moves rapidly at the plasma membrane, it loses its mobility and becomes stably associated with aggregated rafts to ensure organized and sustained signal transduction required for T cell activation.

Hepatocyte growth factor gene transfer into the liver via the portal vein using electroporation attenuates rat liver cirrhosis

Although a variety of gene transfer methods to the liver have been designed, there are some problems such as the transfection efficiency and safety. In the present study, we developed a modified method of gene transfer into the liver by infusion of plasmid DNA via the portal vein followed by electroporation. After green fluorescence protein gene transfer, transgene expressions were detected in 24 h, and then maximally at 3 days, and persisted for 3 weeks. Histological analysis revealed that very mild tissue damage was induced in the liver to which electroporation was applied. In the second study, human hepatocyte growth factor (HGF) was more detected in the liver injected with 500 μg of human HGF gene than 100 μg of human HGF gene. However, serum HGF did not increase with 100 or 500 μg of human HGF gene. Moreover, 500 μg of HGF gene transfer into the liver by using this method could achieve the long survival of all dimethylnitrosamine-treated rats and attenuate the fibrous regions in the liver. These results suggest that HGF gene transfer into the liver via the portal vein using electroporation might be one of the useful methods for the treatment of various liver diseases.

Skeletal muscle targeting in vivo electroporation-mediated HGF gene therapy of bleomycin-induced pulmonary fibrosis in mice

Lung fibrosis is a common feature of interstitial lung diseases, and apoptosis and fibrinogenesis play critical roles in its formation and progression. Hepatocyte growth factor (HGF) is one of the ideal therapeutic agents for prevention of lung fibrosis because of its antiapoptotic and fibrinolytic effects. The aim of this study is to establish nonviral HGF gene therapy of bleomycin-induced lung fibrosis avoiding the viral vector-related side effects. C57BL/6 mice were injected with 3.0 mg/kg body weight of bleomycin intratracheally. Following bleomycin injection, 50 μl of pUC-HGF (1 mg/ml) was injected into each of the quadriceps muscle. Immediately after plasmid injection, in vivo electroporation was performed with pulse generator. Skeletal muscle-targeting electroporation induced transgene expression on day 1 and persisted for 4 weeks, and human HGF was also detected in the lung. In mice transferred with HGF, pathological score (1.0±0.3 vs 3.2±0.6), TUNEL-positive cell index (4.5±1.1 vs 14.2±3.1), and hydroxyproline content (9.0±1.3 vs 14.4±5.1 μmol/g) were significantly reduced compared with the control. Furthermore, survival rate of HGF mice was significantly improved compared with the control. Our data indicate that HGF gene therapy with a single skeletal muscle-targeting electroporation has a therapeutic potential for bleomycin-induced lung fibrosis and this strategy can be applied as a practical gene therapy protocol for various organs.

Abdominal aortic aneurysm with arteritis in ankylosing spondylitis

Abdominal aortic aneurysm with arteritis in ankylosing spondylitis is described. An abdominal aortic aneurysm, 48-mm in diameter, in a 68-year-old woman with HLA-B27-associated ankylosing spondylitis was successfully replaced with a tube graft. The suture lines of the aortic wall were reinforced with Teflon felt strips. Pathologic examination of the aneurysmal wall revealed hyalinization of the connective tissue, with numerous lymphocytic infiltrates, remarkable calcification, and no elastic fibers. The original structure of the arterial wall was not recognized. These findings are compatible with aortitis reported in ankylosing spondylitis.

Antegradely insertable aortic balloon occlusion catheter for aortic arch repair.

Abstract We have developed an antegradely insertable aortic balloon occlusion catheter for aortic arch repair, and review our experiences of using it. The purpose of the present study was to examine the usefulness of the balloon for surgical treatment of aortic arch aneurysm. In 30 patients with aortic arch aneurysm, including 22 with a non-ruptured and 8 with a ruptured aneurysm, the catheter was antegradely inserted into the descending thoracic aorta through the aortic arch or the aneurysm without opening the pleural space after establishing antegrade selective cerebral perfusion and obtaining cardiac arrest. During distal anastomosis, the catheter occluded the aorta with continuous perfusion of the lower half of the body through an arterial cannula inserted into the femoral artery. Among the patients with a nonruptured aneurysm, two deaths (9.1%) occurred because of aorto-broncho-esophageal fistulae or cardiac arrest due to severe asthma attack within 30 days, and the other three hospital deaths were due to aspiration pneumonia, multiple organ failure with preoperative renal dysfunction, or low cardiac output syndrome due to perioperative myocardial infarction. Among the patients with a ruptured aneurysm, three deaths (37.5%) were due to acute myocardial infarction, respiratory failure, or intractable arrhythmia within 30 days, and another hospital death was caused by mediastinitis. No paraplegia was caused in any patient excluding one of the patients with a ruptured aneurysm who could not be weaned from the extracorporeal circulation due to perioperative myocardial infarction. There was no early postoperative serious visceral organ dysfunction except for two patients with postoperative low cardiac output syndrome or preoperative severe renal dysfunction. This catheter was effective in protecting the visceral organs and the spinal cord in the repair of an aortic arch aneurysm.

Surgical outcome of abdominal aortic aneurysm repair in patients undergoing chronic hemodialysis

Abstract. Abdominal aortic aneurysm repair in patients undergoing chronic hemodialysis presents several surgical difficulties due to tissue fragility, accelerated atherosclerosis, and calcification of the aorta. In addition to these surgical procedure-related problems, anemia, electrolyte abnormalities, bleeding tendency, and susceptibility to infection were also critical issues in perioperative management. The aim of this study was to examine the surgical outcome of abdominal aortic aneurysm repair in patients undergoing chronic hemodialysis. Between January 1988 and August 2001, six patients undergoing chronic hemodialysis underwent repair of an abdominal aortic aneurysm. There were five males and one female, and the mean age was 65 years. Two of the six patients had bilateral common iliac artery aneurysms in addition to the abdominal aortic aneurysm. At the time of abdominal aortic aneurysm repair, the duration of hemodialysis had ranged from 3 to 109 months, with a mean of 34 months. All patients underwent hemodialysis on the day prior to the abdominal aortic aneurysm repair operation. The first postoperative hemodialysis was scheduled to be performed on the day after operation or later. The mean duration of operation was 291 min. Blood transfusion was required in all patients. The first postoperative hemodialysis was performed between the first and third postoperative days. Postoperative complications were: ileus in one, and atrial fibrillation and blue toe syndrome just after operation in one. There was no hospital death. The follow-up period was 56 months. One patient died of lingual cancer at 102 months after operation. Five patients are alive. Abdominal aortic aneurysm repair can be done in patients on chronic hemodialysis with an acceptable early and long-term outcome.

Abdominal aortic aneurysm related to Takayasu arteritis during pregnancy

Y. Umeda (*) · Y. Mori · H. Takagi · H. Iwata · Y. Fukumoto · H. Hirose First Department of Surgery, Gifu University School of Medicine, 40 Tsukasa-machi, Gifu 500-8705, Japan Tel. 81-58-267-2619; Fax 81-58-267-2955 e-mail: umeda@cc.gifu-u.ac.jp A cystic lesion in a 34-year-old woman was found incidentally at the dorsal side of the uterus during her pregnancy on ultrasound examination and magnetic resonance (MR) imaging (Fig. 1). Computed tomography (CT) was not performed at that time because of her pregnancy. An ovarian cyst was suspected and followed up by the obstetrician. After a natural delivery, a pulsatile mass was found in the left upper abdomen and she was then referred to our hospital. An infrarenal fusiform abdominal aortic aneurysm with a maximum diameter of 6cm was revealed on a CT scan (Fig. 2). She had no history of hypertension or abdominal trauma. The abdominal aortic aneurysm was repaired with a tube graft via a midline laparotomy. She recovered uneventfully after the operation and was discharged from the hospital. Histological examination revealed fibrous thickening of the intima, diffuse lymphohistiocytic infiltration and marked destruction of elastic fibers especially on the adventitial side of the media, and proliferation of the vasa vasorum with perivascular infiltration of lymphocytes in the adventitia. These changes corresponded with the pathologic finding of Takayasu arteritis. Takayasu arteritis is an idiopathic inflammatory arteriopathic disease that leads to stenotic or occlusive changes in the aorta and its main branches. However, aneurysmal formation has also been reported in 2%–30% of Takayasu arteritis patients. Therefore, even in young people, aortic aneurysm related to Takayasu arteritis should not be excluded from the diagnosis of abnormality in an aortic lesion.

Simultaneous Operations for Combined Thoracic and Abdominal Aortic Aneurysms

AbstractPurpose. To assess whether simultaneous operations are appropriate for combined thoracic and abdominal aortic aneurysms. Methods. Simultaneous operations were performed for combined thoracic and abdominal aortic aneurysms in nine patients. The thoracic aortic aneurysm (TAA) was repaired first, followed by repair of the abdominal aortic aneurysm (AAA). Selective cerebral perfusion was used in eight patients, after the exception of one who underwent replacement of the ascending aorta under hypothermic circulatory arrest. The abdominal organs were perfused during distal anastomosis in surgery for Stanford type A aortic dissection or aortic arch aneurysm; via the femoral artery with an aortic balloon occlusion catheter in one patient, and via an occlusion catheter with a perfusion lumen in two patients. Results. All patients underwent planned simultaneous repair of the AAA. One of the patients who underwent simultaneous replacement of both the descending thoracic and abdominal aorta was left with paraplegia, and one patient died suddenly of massive hemoptysis and melena on the 29th postoperative day. Autopsy revealed that the bleeding had been caused by aorto-broncho-esophageal fistulae. The overall operative mortality was 11%. Conclusions. Simultaneous repair of combined TAA and AAA can be safely performed; however, the risk of paraplegia should be considered, especially with simultaneous repair of concomitant aneurysms of the descending thoracic and abdominal aorta.

A Successful Case of Ascending Aorta—Abdominal Aorta Bypass for Middle Aortic Syndrome

The middle aortic syndrome (MAS) is a rare disease affecting children and young adults, and it occurs in about 0.5% to 2.0% of all aortic coarctation cases. Congenital, acquired, inflammatory, and infectious etiologies have been described. In the majority of cases, there is a short, isolated or diffuse tubular narrowing of the descending thoracic and abdominal aorta, often accompanied by ostial stenosis or occlusion of the renal and visceral branches, which leads to renovascular hypertension and visceral ischemia. Surgical treatment should be considered in cases of uncontrollable hypertension, evidence of end-organ damage such as cardiac failure, progressive renal insufficiency, or severe intermittent claudication. Several surgical treatments for this condition have been reported, including bypass grafting, graft replacement, or patch angioplasty. We report a successful case of ascending aorta—abdominal aorta bypass for MAS in a 11-year-old boy.

Surgical treatment of thoracoabdominal aortic mural and floating thrombi extending to infrarenal aorta

The case of a 49-year-old man with thoracoabdominal aortic mural and floating thrombi extending to the infrarenal aorta and occlusion of the common iliac artery is described. He had no factors promoting thrombosis, with a history of thrombectomy of the femoral artery. The thoracoabdominal aortic thrombi were successfully removed with a Forgaty catheter through a thoracotomy under simple aortic clamping and subsequent femoro-femoral cardiopulmonary bypass. Intravascular ultrasound performed through the femoral artery after thrombectomy revealed that little mural thrombi remained and that the celiac, superior mesenteric, and bilateral renal arteries were all patent.