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Koichi Tabayashi

Publications and source records attributed to Koichi Tabayashi.

At least 19 recordsLinked to original sources
PubMed2006

Up-regulation of matrix metalloproteinase-2 and membrane-type 1-matrix metalloproteinase were coupled with that of type I procollagen in granulation tissue response after the onset of aortic dissection.

The pathophysiological significance of matrix metalloproteinases (MMPs) in aortic dissection remains poorly understood. The purpose of the present study is to clarify the significance of MMPs in aortic dissection. The activities and distributions of MMP-2, membrane-type 1-MMP (MT1-MMP), and MMP-9 were evaluated by gelatin zymography, immunohistochemistry, and in situ hybridization in 29 patients and seven autopsy cases. To assess if these MMPs are related to a tissue remodeling process, we compared the expression of these MMPs with that of type I procollagen and platelet-derived growth factor receptor beta chain (PDGF Rbeta). Patients were divided into three groups based on histological findings: acute, intermediate, and healed groups. The most remarkable changes were observed in the intermediate group, in which MMP-2 activity peaked and tissue expression of mRNAs for MMP-2 and MT1-MMP were observed in spindle-shaped cells in the neointima, organizing thrombus, and the adventitia. These expression patterns were essentially coupled with those of type I procollagen mRNA and PDGF-Rbeta protein. The association of MMP-2, MT1-MMP, type I procollagen, and PDGF-Rbeta suggests that MMP-2 and MT1-MMP could be involved not only in the degradation of aortic tissue but also in tissue remodeling, which may be associated with the healing process.

Aged↗
PubMed2006

Isolation and characterization of vasohibin-2 as a homologue of VEGF-inducible endothelium-derived angiogenesis inhibitor vasohibin.

OBJECTIVE: We recently isolated vasohibin, a novel vascular endothelial growth factor (VEGF)-inducible endothelium-derived angiogenesis inhibitor. Our aim is to find DNA sequences homologous to vasohibin and determine their expression profile. METHODS AND RESULTS: By the search of DNA sequences in the database, we found one homologous gene and designated it vasohibin-2. Overall amino acid sequence homology between the prototype vasohibin (vasohibin-1) and vasohibin-2 was >50%. Vasohibin-2 exhibited antiangiogenic activity. Vasohibin-2 expression in cultured endothelial cells was low and not inducible by the stimulation that induced vasohibin-1. However, the immunohistochemical analysis revealed that vasohibin-1 and -2 were diffusely expressed in endothelial cells in embryonic organs during mid-gestation. After that time point, vasohibin-1 and -2 became faint, but persisted to a certain extent in arterial endothelial cells from late gestation to neonate. Expression of vasohibin-1 and -2 could be augmented in vivo by local transfection with the VEGF gene in the embryonic brain or by cutaneous wounding in adult mice. CONCLUSIONS: These results suggest that vasohibin-2, in combination with vasohibin-1, forms a novel family of angiogenesis inhibitors.

Angiogenesis Inhibitors↗
PubMed2006

Redo total aortic arch replacement using an extended homograft for graft infection.

A 65-year-old man developed graft infection 3 years after total aortic arch replacement for a chronic dissecting aneurysm. Redo total aortic arch replacement was performed using an extended homograft following 2 days of open drainage of the mediastinum. The patient has been free from a recurrent mediastinitis over the last 3 years.

Aged↗
PubMed2006

The wrapping method using biodegradable felt strips has a preventive effect on the thinning of the aortic wall: experimental study in the canine aorta.

OBJECTIVES: Wrapping methods have been widely used to reinforce the anastomotic site in vascular surgery; however, postoperative changes in the aortic wall wrapped by nonbiodegradable felt have not been well characterized. The purposes of this investigation are to elucidate the sequelae of wrapping with nonbiodegradable felt on the aortic wall and to modify those changes by using biodegradable felt with or without basic fibroblast growth factor (bFGF). METHODS: The descending thoracic aortas of 15 beagles were wrapped with three different materials: nonbiodegradable polytetrafluoroethylene (PTFE) felt, biodegradable polyglycol acid (PGA) material, and PGA with 100 microg bFGF (n = 5 in each group). The descending thoracic aorta was resected after 3 months. The thickness of the aortic wall, vessel density in the media and the adventitia, and the wall strength were assessed. Untreated native aortic wall served as a normal control. RESULTS: The thickness of the media of the PTFE group was lower than that of the PGA + bFGF group (66% +/- 5% vs 85% +/- 6% of control, P < .05). The adventitia-media ratio in the PTFE group decreased compared with controls (59.1% of normal, P < 0.05), whereas those in the PGA and PGA + bFGF groups increased (172.1% and 189.6% of normal, respectively, P < .01). The collagen-smooth muscle ratio in the media was higher in the PTFE group than in the controls (0.14 +/- 0.02 vs 0.07 +/- 0.01, P < .01). The number of vessels in the adventitia was higher in the PGA + bFGF group than those in PTFE or PGA groups (29.6 +/- 2.5/mm2 vs 6.4 +/- 0.8/mm2, 19.0 +/- 1.1/mm2, P < .01). The PGA + bFGF group demonstrated larger failure force than the PTFE group (4.0 +/- 0.3 kgf vs 1.6 +/- 0.3 kgf, P < .01). The failure stress in the PGA and PGA + bFGF groups was larger than that in PTFE group (PTFE:PGA + bFGF = 5.3 +/- 0.9 x10(2) kPa:11.7 +/- 1.7 x 10(2) kPa, P < .01; PTFE:PGA = 5.3 +/- 0.9 x 10(2) kPa:11.2 +/- 1.2 x 10(2) kPa, P < .05). CONCLUSION: The aortic wall wrapped with nonbiodegradable PTFE felt showed a reduced thickness and diminished vessels in the adventitia. Biodegradable felt (PGA), with or without bFGF, modified these histologic changes. The vessel-rich thickened adventitia, after wrapping by PGA with bFGF, was associated with increased aortic wall strength. CLINICAL RELEVANCE: This investigation was conducted in an attempt to elucidate mechanisms underlying the occurrence of late postoperative false aneurysm after aortic surgery. We hypothesized that sustaining compression of the aorta by the felt strip may cause structural derangement and local ischemia on the aortic wall. We used a simple wrapping of the aorta with a felt strip rather than a felt strip at anastomotic sites to simplify the experimental model and to exclude confounding factors brought by technical inconsistency on the surgical anastomosis. We further attempted to find a clue for preventing adverse effects of wrapping with a conventional felt strip. Practically, we pursued a possible application of a biodegradable felt strip to aortic wrapping in our experimental model before we proceed in a clinical application of the new material.

Aneurysm, False↗
PubMed2006

[Endovascular stent-grafting of ruptured aortic aneurysms].

Ruptured thoracic aortic aneurysms expose the patient to a major risk of death and remain a therapeutic challenge. Hemorrhage control and prevention of fatal bleeding are primary treatment goals in this medical emergency. Early postoperative mortality of surgically treated patients is estimated to be still high. An increasing number of reports on successful endovascular treatment of the ruptured thoracic aortic aneurysms by endovascular stent-grafting have been published, and they provide better early results. Since 2002, 59 patients with thoracic aortic aneurysms have been treated with the endovascular technique using stent-graft in our institute. Initial success of stent-grafting, which means exclusion of the aneurysms without endoleak, were achieved in 98.3%. Treatment using stent-grafting for ruptured thoracic aortic aneurysms (13/ 59) also presented satisfactory early outcome. Endovascular stent-grafting is a low invasive and useful treatment for ruptured thoracic aortic aneurysms, and is strongly recommended if the aneurysms are morphologically susceptible.

Adult↗
PubMed2005

Vacuum-assisted closure system for the treatment of mediastinitis after total aortic arch replacement.

A 77-year-old man developed deep sternal wound infection with Enterobacter cloacae 4 days after total aortic arch replacement for distal aortic arch aneurysm. Reexploration and open drainage of the mediastinum was carried out for 4 days, and the vacuum-assisted closure system was applied and continued for 10 days. During the treatment, granulation formation and neovascularization was apparently enhanced which lead us to perform omental transfer and chest closure on the 18th postoperative day. The patient has been free from recurrent sign of mediastinal infection or graft infection for the 19 months of the follow-up period.

Aortic Dissection↗
PubMed2005

Spinal cord protection during thoracoabdominal aneurysm repair.

Spinal cord injury after thoracoabdominal aortic surgery remains a devastating and unpredictable complication, caused by clamping of the thoracoabdominal aorta, resulting in exclusion of blood flow in critical and essential intercostal arteries. Various protective methods against spinal cord ischemia have been proposed and performed clinically. These include preoperative spinal angiography, distal aortic perfusion, hypothermia, reattachment of the intercostal artery, cerebrospinal fluid drainage, administration of neuroprotective agents, and monitoring of somatosensory and motor-evoked potentials. The information to date suggests that multimodality approaches should be used to prevent spinal cord injury after thoracic and thoracoabdominal aneurysm repair.

Aortic Dissection↗
PubMed2005

Results of aortic surgery in patients with Marfan syndrome.

PURPOSE: We reviewed the outcome of aortic operations in patients with Marfan syndrome to evaluate the immediate and long-term results of surgical treatment. METHODS: Between January 1985 and June 2002, 22 patients with Marfan syndrome underwent surgical treatment for aortic diseases at our hospital. Eight patients had Stanford type A aortic dissection and ten patients had aortic root aneurysm with aortic regurgitation. We performed aortic root replacement in 21 patients. Subsequent aortic operations were done in 11 patients, 6 of whom required a third operation. Five patients underwent repeat surgery of the previously operated aortic segment. A collective a total of 42 aortic operations were performed in the 22 patients. Seven patients underwent total aortic replacement. RESULTS: The in-hospital mortality rate was 4.5%, and there were three late deaths: two caused by rupture of the dissected aorta, 17 months and 24 months after the last surgical intervention, respectively, and one caused by heart failure 27 months after a total aortic replacement. The overall actuarial survival was 90.2% at 5 years and 74.4% at 10 years. CONCLUSIONS: Surgical treatment of patients with Marfan syndrome can be accomplished with low mortality; however, new aortic lesions should be promptly explored, and appropriately timed surgical treatment can substantially improve the prognosis of patients with Marfan syndrome.

Actuarial Analysis↗
PubMed2005

Japanese multicenter clinical evaluation of the HeartMate vented electric left ventricular assist system.

Implantable left ventricular assist device systems (LVAS) are increasingly being used to bridge patients to heart transplantation because of the limited number of available donor hearts. This prospective, multicenter trial was designed to evaluate the usefulness of the HeartMate vented electric (VE) LVAS as a bridge to transplantation in Japan. Between November 2001 and June 2003, six patients with end-stage heart failure [New York Heart Association (NYHA) class IV] were supported with the LVAS and five of the six were able to implement the evaluation (one dropped out). The five were men with an average age of 38.6 years and were supported for 2390 cumulative days (6.6 years). Average preimplant cardiac index improved from 1.93 l/min/m(2) to a 3.79 l/min/m(2) VAD flow index at the end of the clinical trial. All five patients improved to NYHA class I or II, survived more than 1 year, and one patient was discharged from the hospital. Mean LVAS support duration was 478 days (range 390-575 days) and four patients remain supported. One patient died from cardiac failure and sepsis. Device-related complications included: infections (four patients), thromboembolism (one patient), hemolysis (two patients), and repeat operation for bleeding (two patients). There was one case of inflow valve incompetence and two pump motor malfunctions. We conclude that the LVAS can effectively support patients as they await cardiac transplantation and offers improvement to the patient's quality of life.

Adult↗
PubMed2005

Surgical treatment of a retrosternal pseudoaneurysm arising from the posterior aortic root.

We report a case of a 60-year-old male with a retrosternal pseudoaneurysm arising from the posterior aortic root. He had undergone replacement of the aortic root and ascending aorta for an acute aortic dissection. His postoperative course was complicated with composite graft infection. During a redo surgery, femoro-femoral bypass was established prior to sternotomy via the right femoral artery and vein, and ten French cannulas were directly inserted into both carotid arteries through separate skin incisions for brain perfusion. When the sternum was divided, an occlusion balloon catheter introduced through the left femoral artery was inflated to maintain somatic perfusion without compromising clear vision of the operative field. Combined procedures with direct cannulation into both common carotid arteries and balloon occlusion of the distal aortic arch allowed us to safely perform replacement of the aortic root and ascending aorta in the patient with a retrosternal pseudoaneurysm.

Aneurysm, False↗
PubMed2005

Closure of the pericardium using synthetic bioabsorbable polymers.

BACKGROUND: Pericardial substitutes are known to ensure safer resternotomy at reoperation. A synthetic sheet made from expanded-polytetrafluoroethylene (e-PTFE) has been most commonly used as a pericardial substitute. The e-PTFE sheet, however, can induce severe inflammatory reaction and diffuse fibrosis. This study was designed to investigate the absorption rate and tissue reaction associated with two absorbable pericardial substitutes: a gelatin sheet and L-lactic acid-epsilon-caprolactone copolymer (L-C copolymer). In addition, e-PTFE sheet and autologous pericardium were used as controls. METHODS: Sixty dogs were divided into four groups of 15. In group A, a 3 x 3 cm segment of pericardium was excised, and the autologous pericardium was resutured. In group B, the pericardial defect was replaced with gelatin sheet. In group C, the defect was replaced with L-C copolymer sheet. In group D, the defect was replaced with e-PTFE sheet. For each group, the implanted membranes were retrieved at 2 weeks (n = 1), 4 weeks (n = 3), 12 weeks (n = 5), and 24 weeks (n = 6) after implantation. RESULTS: The e-PTFE sheet produced severe adhesions to the heart and pleura and a more prominent inflammatory reaction, as compared with the gelatin sheet. The absorbable pericardial substitutes were completely absorbed by 24 weeks after implantation, and were replaced with fibrous membrane. CONCLUSIONS: Gelatin sheet may involve less adhesion and a reduced inflammatory reaction compared with e-PTFE.

Absorbable Implants↗
PubMed2005

Stent grafting technique using Matsui-Kitamura (MK) stent for patients with aortic arch aneurysm.

OBJECTIVE: Although several methods of stent-grafting for patients with aortic arch aneurysm have been reported, these methods have been associated with several complications such as endoleak and migration. We developed a new method using Matsui-Kitamura (MK) stent-graft following extra-anatomic arch vessels bypass by selective cerebral perfusion (SCP) under left heart bypass (LHB). METHODS: Between December 2001 and December 2003, 12 patients with aortic arch aneurysm were treated according to this new method. All patients were male with an average age of 71.3+/-6.4 years. There were 5 patients with severe pulmonary dysfunction, 4 with renal dysfunction, one with severe cardiac dysfunction and 3 with preoperative cerebral infarction. Under SCP using LHB, the extra-anatomic arch vessel bypass was established. The MK stent-graft was delivered into the aortic arch. Coronary artery bypass grafting (CABG) was concomitantly performed in one patient. RESULTS: There were no cases of endoleak, migration or hospital death. One patient, who had a past history of cerebrovascular disease, suffered a minor stroke, and one patient, who was performed CABG to the mid-left anterior descending branch (LAD) using the left internal thoracic artery (LITA), presented paraparesis. Although two patients of chronic renal failure underwent scheduled CHDF on account of using the contrast medium during the procedure, all of them were weaned from hemodialysis. However, there were no other postoperative complications such as, respiratory failure or cardiac dysfunction. CONCLUSIONS: Endovascular stent grafting EVSG using the MK stent with extra-anatomic arch vessel bypass under SCP using LHB could be a useful and less invasive method for patients with aortic arch aneurysm who are at a high surgical risk.

Aged↗
PubMed2005

Endoplasmic reticulum stress induced in motor neurons by transient spinal cord ischemia in rabbits.

OBJECTIVE: The mechanism of spinal cord injury has been thought to be related to the vulnerability of spinal motor neuron cells against ischemia. However, the mechanisms of such vulnerability are not fully understood. Because we previously reported that spinal motor neurons were probably lost as the result of programmed cell death, we investigated a possible mechanism of neuronal death by immunohistochemical analysis for Grp78 and caspase12. METHODS: We used a rabbit spinal cord ischemia model with a balloon catheter. The spinal cord was removed at 8 hours or 1, 2, or 7 days after 15 minutes of transient ischemia. Histologic changes were studied with hematoxylin-eosin staining. Western blot analysis for Grp78 and caspase12, temporal profiles of Grp78 and caspase12 immunoreactivity, and double-label fluorescence immunocytochemical studies were performed. RESULTS: The majority of motor neurons were preserved for 2 days but were selectively lost at 7 days of reperfusion. Western blot analysis revealed scarce immunoreactivity for Grp78 and caspase12 in the sham-operated spinal cords. However, immunoreactivity for Grp78 and caspase12 became apparent at 8 hours after transient ischemia, which returned to the baseline level at 1 day. Double-label fluorescence immunocytochemical study revealed that both Grp78 and caspase12 were positive at 8 hours of reperfusion in the same motor neurons that eventually die. CONCLUSION: This study demonstrated that immunoreactivities for both Grp78 and caspase12 were induced in the same motor neuron that eventually dies. These results suggest that endoplasmic reticulum stress was induced in motor neurons by transient spinal cord ischemia in rabbits.

Animals↗
PubMed2005

[Treatment strategy for patients with concomitant thoracic or abdominal aortic aneurysm and noncardiovascular disease].

Therapeutic planning for patients with concomitant thoracic aortic aneurysm (TAA) or abdominal aortic aneurysm (AAA) and noncardiovascular disease such as cerebral aneurysm, carotid artery stenosis, or lung, intraabdominal or urologic tumor should be considered based on the combination of the two different conditions, the size of aneurysm, or the severity of noncardiovascular disease. The aims of this paper are to review the therapeutic plans for concomitant TAA or AAA and noncardiovascular disease. In patients with concomitant TAA or AAA and cerebral aneurysm, carotid artery stenosis, and concomitant TAA and intraabdominal or urologic tumor, the surgical procedures have usually been staged with the repair of cerebral aneurysm, or carotid artery stenosis, the resection of intraabdominal or urologic tumor performed first, followed by the repair of TAA or AAA. Simultaneous surgical treatment has been performed for most patients with concomitant TAA and lung tumor, and concomitant AAA and intraabdominal or urologic tumor. The issue of performing simultaneous pulmonary resection and repair of AAA in patients with concomitant lung tumor and AAA remains controversial. Endovascular grafting of TAA and AAA can be performed with relatively low procedure-related morbidity and mortality rates in selected patients.

Aortic Aneurysm, Abdominal↗
PubMed2005

In vivo mechanical properties of thoracic aortic aneurysmal wall estimated from in vitro biaxial tensile test.

To investigate the mechanism of aneurysm rupture, it is necessary to examine the mechanical properties of aneurysm tissues in vivo. A new approach to evaluate in vivo mechanical properties of aortic aneurysmal tissues has been proposed in this study. The shape of the aneurysm was modeled as a sphere, and equi-biaxial stress in the in vivo state was estimated from the diameter and the wall thickness of each aneurysm and mean blood pressure of each patient. The mechanical properties of the aneurysm at the in vivo stress were estimated from its in vitro biaxial tensile properties. There were no significant correlations among maximum diameter D, wall thickness t, and mean infinitesimal strain in the in vivo state epsilon(m). This indicates the wall deformation during aneurysm development was not elastic but plastic. The mean incremental elastic modulus H(m), an index of tissue stiffness, had a significant positive correlation with elastic modulus anisotropy index K(H). This indicates the aneurysmal wall got more anisotropic in vivo as it becomes stiffer.

Anisotropy↗