Search PubMed⌕ Search

Biomedical subjects

Shinichi Takamoto

Publications and source records attributed to Shinichi Takamoto.

At least 19 recordsLinked to original sources
PubMed2007

Is interstitial pneumonia in patients with collagen diseases a contraindication to lung cancer surgery?

PURPOSE: Lung cancer surgery can be dangerous in patients with interstitial pneumonia (IP) as acute exacerbation of the IP may prove fatal. It remains unclear if patients with collagen diseases (CD), who often suffer from IP, are also at increased risk during lung cancer surgery. METHODS: We retrospectively examined 17 (3.1%) patients with CD among 545 patients who underwent surgery for lung cancer at our institution. RESULTS: Nine patients with rheumatoid arthritis, five with systemic sclerosis, two with Sjögren's disease, and one with systemic lupus erythematosus were enrolled in this study. Eleven patients (65%) were taking corticosteroids at the time of surgery. Fourteen patients underwent lobectomy and lymph node dissection, and three patients with pStage IA lung cancer underwent pulmonary wedge resection. Pathologically, 11 (65%) patients had IP with various inflammatory cellular infiltrations, and three (18%) had honeycombing of the lung. Postoperatively, none of the patients suffered acute exacerbation of their IP. CONCLUSIONS: Despite the high incidence of IP in patients with lung cancer and CD, our results suggest that CD is not a contraindication to the surgical resection of lung cancer.

Aged↗
PubMed2006

The beneficial effect of coronary-artery-bypass surgery on survival in patients with diabetic retinopathy.

OBJECTIVE: The presence of retinopathy is a predictor of mortality following coronary revascularization in diabetics. We studied whether revascularization by coronary-artery-bypass surgery (CABG), as compared with percutaneous coronary intervention (PCI), influences the prognosis in diabetics with retinopathy. METHODS: Between April 1996 and March 2004, 1489 patients underwent revascularization as an initial procedure. Among these a total of 319 diabetics underwent retinal examination prior to the initial revascularization. These patients were classified according to whether they had retinopathy and whether they had undergone CABG, either initially or after PCI. Mortality rates were estimated from the time of initial revascularization procedure. RESULTS: The average follow-up from the time of initial revascularization was 48.2+/-28.6 months. In 153 diabetics with retinopathy, 59 eventually underwent CABG. During the entire follow-up period, there were 2 (3.4%) deaths in diabetics with retinopathy who underwent CABG and 14 (14.9%) deaths in those who did not have CABG. Mortality curves differed significantly between the two groups (P = 0.007). After adjustment for risk factors, the relative risk of death was 0.13 afforded by CABG (95% CI, 0.03-0.62; P = 0.011). In 166 diabetics without retinopathy, mortality curves were similar between the patients who underwent CABG and those who did not have CABG (P = 0.94). CONCLUSIONS: CABG conferred a survival advantage in diabetics with retinopathy. In contrast, no survival advantage was evident in diabetics without retinopathy undergoing CABG. Retinal status should be taken into consideration when considering revascularization strategy for diabetics who have coronary artery disease.

Aged↗
PubMed2006

A simple modification of 'David-V' aortic root reimplantation.

Valve-sparing aortic root reimplantation with creation of Dacron graft pseudosinuses is a popular and promising surgical choice for annuloaortic ectasia or ascending aortic aneurysm. We have developed a simple modification of the David-V technique, which facilitates free adjustment of the size of the new aortic annulus and the pseudosinus of each patient, as well as the creation of pseudosinuses of excellent shape, with only one Dacron graft.

Aorta↗
PubMed2006

Cryopreservation does not alter the allogenicity and development of vasculopathy in post-transplant rat aortas.

BACKGROUND: Cryopreservation is a valuable technique for storing heart valve and vascular allografts. However, the biological ramifications of cryopreservation are still unclear; therefore, using animal experiments we assessed how 'cryopreservation' influences graft allogenicity and cell viability. METHODS: Thoracic aortas of Lewis rats were prepared as fresh (F) or cryopreserved (CP) grafts, and implanted into the infrarenal aorta of Lewis or Brown Norway rats (BNs). The grafts and spleens were harvested at post-operative day 7 and 28 (POD7, POD28) for analyses. RESULTS: First, the systemic immune response to transplantation was estimated by mixed lymphocyte reaction analyses using spleen cells from naïve or recipient BNs. The alloreactivity of the recipients increased to 1.5 times that of the naïve BNs at POD7 and POD28, when stimulated by mitomycin C-treated Lewis spleen cells. Second, local immune response was estimated by TNFalpha, IFNgamma, and iNOS mRNA expression in the grafts by quantitative PCR, which revealed 20- to 40-fold increases at POD28 after allotransplantation. Third, endothelial cell viability was estimated by endothelial NOS mRNA expression level: it was similar and highest in F and CP grafts before transplantation then significantly decreased after both syngeneic and allogeneic transplantation. Finally, intimal hyperplasia, expressed by I/M ratio, developed over time after allotransplantation, reaching 2.5 times the thickness of F grafts before transplantation. The results of these experiments revealed no difference between F and CP grafts before and after transplantation. CONCLUSION: Cryopreservation did not modify the allogenicity of vascular allografts and had minimal adverse impacts on graft cell viability.

Animals↗
PubMed2006

Portal vein reconstruction in adult living donor liver transplantation using cryopreserved vein grafts.

No data are available for the management of venous jump or interposition conduits for portal vein (PV) reconstruction in adult living donor liver transplantation (LDLT). The feasibility of using cryopreserved vein grafts as PV conduits was examined. Cryopreserved vein (n = 23) was used as a patch, interposition, or jump graft. The patency results were compared with those of anastomosis without vein patch (n = 217) or those with vein autografts (n = 10). The 5-yr primary and secondary patency rates of the cryopreserved vein grafts were 58% and 79%, respectively. In conclusion, our data indicate that the use of cryopreserved vein grafts should be limited as conduits in PV reconstruction in adult LDLT.

Adult↗
PubMed2006

Complete coverage of in situ aortograft by total omental pedicle flap as the most reliable treatment of aortoesophageal fistula.

Aortoesophageal fistula secondary to a thoracic aortic aneurysm is usually a fatal disease with few survivors reported previously. We encountered 2 consecutive patients who were treated successfully with esophagectomy and in situ aorta reconstruction using cryopreserved homograft that was wrapped completely with omental pedicle flap. For the construction of omental flap, the right gastroepiploic artery was resected at the root and all the vessels entering the greater curvature and the transverse colon were resected at the adherent edges. Because the gastroepiploic arcade is totally preserved, large amounts of omental tissue could be obtained, with an excellent blood supply mainly from the left gastroepiploic artery. This type of omental flap is highly mobile, easily transferred to the left hemithorax, and has enough volume to cover the in situ aortic graft completely including anastomosis lines. Thus, our omental coverage appears to be the most reliable method to prevent postoperative graft infection.

Aged↗
PubMed2006

Prevention of postoperative pericardial adhesions with a novel regenerative collagen sheet.

BACKGROUND: Postoperative pericardial adhesions make a repeat sternotomy time-consuming and dangerous. The purpose of this study was to evaluate the efficacy of a new collagen pericardial substitute for preventing postoperative pericardial adhesions. METHODS: Our absorbable substitute consists of three layers: a middle layer of aterocollagen between two layers of sodium hyaluronic acid and aterocollagen. In experiment 1 in this study, the patch, made of 9,000 filaments of aterocollagen fibers, (group 1; n = 5) was compared with a patch made of 6,000 filaments (group 2; n = 7), an expanded polytetrafluoroethylene sheet (group 3; n = 6), and a control group (group 4; n = 4). Subsequently, in experiment 2, the patch was examined at 4 weeks (n = 5), 12 weeks (n = 5), and 24 weeks (n = 4) after the operation by light microscopy and scanning electron microscopy. RESULTS: The area of adhesion in group 1 was significantly less as compared with that in the other three groups, and the coronary vessels were clearly identifiable; on the other hand, all the animals in the control group showed moderate to severe adhesions, and the coronary vessels were completely obscured. In experiment 2, formation of a membranous tissue resembling the native pericardial membrane was observed in all animals, and the thickness of this membrane showed a marked increase by 24 weeks after the operation. Light microscopy and scanning electron microscopy also showed the formation of a mesothelium-like lining. CONCLUSIONS: The new absorbable and regenerative collagen patch seemed to be biocompatible, and its use was associated with minimal adhesion formation and preserved coronary anatomy.

Animals↗
PubMed2006

Impact of diabetic retinopathy on cardiac outcome after coronary artery bypass graft surgery: prospective observational study.

BACKGROUND: Diabetic retinopathy is a manifestation of more severe diabetes. We sought to assess the impact of diabetic retinopathy on cardiac outcome of coronary artery bypass graft surgery (CABG). METHODS: We prospectively assessed the status of the retina of 74 consecutive diabetics who were referred for first-time CABG, and compared cardiac outcome of CABG in diabetics with retinopathy with that in those without retinopathy. Cardiac events included recurrent angina or congestive heart failure that needed admission to hospital, myocardial infarction, repeat revascularization, and cardiac death. RESULTS: Twenty-six diabetics had retinopathy and 48 diabetics did not have retinopathy. Diabetics with retinopathy were likely to have higher hemoglobin A1c level (p = 0.048), and receive insulin treatment (p = 0.0065). In the 12 months of follow-up, 13 cardiac events occurred in diabetics with retinopathy and 7 in those without retinopathy (p = 0.0021). Among diabetics with retinopathy, heart failure or death due to heart failure accounted for 54% (7 of 13) of these cardiac events. Kaplan-Meier analysis showed significant difference in cardiac event-free survival between the two groups (p < 0.001). After adjustment for differences in patients' characteristics, diabetic retinopathy remained a predictor of cardiac event (adjusted relative risk = 4.2, 95% confidence interval, 1.5% to 11.9%; p = 0.0067). CONCLUSIONS: After CABG, diabetics with retinopathy have a substantially increased risk of cardiac events, especially of congestive heart failure.

Angina Pectoris↗
PubMed2006

Erythropoietin protects the central nervous system during prolonged hypothermic circulatory arrest: an experimental study in a canine model.

OBJECTIVE: Current data suggest that erythropoietin protects the brain and the spinal cord from ischemic and traumatic injury. In this study, we determined whether erythropoietin protects the central nervous system during prolonged hypothermic circulatory arrest in an experimental canine model. METHODS: Ten adult beagle dogs were randomly and intravenously injected with either 5000 U/kg recombinant human erythropoietin or normal saline. Each dog was then subjected to a cardiopulmonary bypass and 120 minutes of deep hypothermic circulatory arrest (18 degrees C). The level of tau proteins in the cerebrospinal fluid, a modified marker of neurologic deficit in dogs, and the histopathologic characteristics of the brains and spinal cords were then examined. RESULTS: The level of tau proteins was significantly lower in the erythropoietin-treated group than in the untreated group at 6 hours (20 +/- 12 vs 144 +/- 54 pg/mL; P = .036) and 12 hours (64 +/- 35 vs 478 +/- 103 pg/mL; P = .01) after the operation. The total Neurologic Deficit Score was 59 +/- 31 (0, normal; 500, brain death) in the erythropoietin-treated group, compared with 376 +/- 30 in the untreated group (P = .0117). Histopathologic examination revealed that ischemic neuronal changes and apoptosis in the hippocampus CA1 were significantly lower in the erythropoietin-treated group (P < .01 and P = .028, respectively). CONCLUSIONS: This study showed that erythropoietin protected the central nervous system during prolonged hypothermic circulatory arrest, partly by preventing both necrosis (ischemic neuronal changes) and apoptosis.

Animals↗
PubMed2006

Intermittent pressure augmentation during retrograde cerebral perfusion under moderate hypothermia provides adequate neuroprotection: an experimental study.

OBJECTIVE: For cerebral protection during aortic surgery, we introduced a novel retrograde cerebral perfusion method with intermittent pressure augmentation. We then assessed whether this novel method provides benefits similar to those provided by antegrade selective cerebral perfusion. METHODS: Eighteen dogs were randomly divided into 3 groups: the RCP-INT group, intermittent-retrograde cerebral perfusion at 15 mm Hg with intermittent pressure augmentation to 45 mm Hg (n = 6); the ASCP group, antegrade selective cerebral perfusion at a flow rate of 10 mL x kg(-1) x min(-1) (n = 6); and the sham group, no circulatory arrest (n = 6). Cooling (26 degrees C) with cardiopulmonary bypass and 60 minutes of circulatory arrest were performed in the RCP-INT and ASCP groups. The levels of tau protein in the cerebrospinal fluid and the diameters of the retinal vessels were measured. The neurologic deficit scores and the histopathologic damage scores of the brains were determined. RESULTS: The total postoperative tau protein levels (calculated as the area under the curve) did not differ significantly between the RCP-INT and ASCP groups (203 +/- 87 pg x mL(-1) x h vs 154 +/- 69 pg x mL(-1) x h, P = .95). The retinal vessels were effectively dilated at an augmented pressure of 45 mm Hg in the RCP-INT group. The total neurologic deficit score (0 = normal, 500 = brain death) and histopathologic damage score (0 = normal, 40 = worst) were not significantly different between the RCP-INT and ASCP groups (neurologic deficit score: 75 +/- 21 vs 70 +/- 21, P = .98; histopathologic damage score: 13.5 +/- 1.5 vs 14.2 +/- 1.3, P = .84). CONCLUSIONS: Intermittent augmented pressure dilated the cerebral vessels, allowing adequate blood supply without injuring the brain. This retrograde cerebral perfusion method provides adequate neuroprotection during moderate hypothermia.

Animals↗
PubMed2006

Retrograde cerebral perfusion with intermittent pressure augmentation provides adequate neuroprotection: diffusion- and perfusion-weighted magnetic resonance imaging study in an experimental canine model.

OBJECTIVE: Diffusion- and perfusion-weighted magnetic resonance imaging can identify ischemic brain injury in the hyperacute stage. For neuroprotection during thoracic aortic surgery, we developed a novel retrograde cerebral perfusion with intermittent pressure augmentation. The purpose of this study was to assess the efficiency of this novel method for neuroprotection in real time by using diffusion- and perfusion-weighted magnetic resonance imaging. METHODS: Sixteen beagle dogs were randomly divided into 4 groups: the antegrade selective cerebral perfusion group (n = 4; antegrade selective cerebral perfusion at a flow rate of 10 mL x kg(-1) x min(-1)); the intermittent retrograde cerebral perfusion group (n = 4; retrograde cerebral perfusion at a baseline pressure of 15 mm Hg with intermittent pressure augmentation to 45 mm Hg every 30 seconds); the conventional retrograde cerebral perfusion group (n = 4; conventional retrograde cerebral perfusion at a fixed pressure of 25 mm Hg); and the circulatory arrest group (n = 4; only circulatory arrest). Diffusion- and perfusion-weighted magnetic resonance images were acquired during each session of cerebral perfusion. Regions of interest were defined, and the apparent diffusion coefficient and relative regional cerebral blood volume were calculated in these regions of interest. Finally, the brain was evaluated for its histopathologic damage score. RESULTS: The best apparent diffusion coefficient values were observed in the intermittent retrograde cerebral perfusion group in all the regions of interest, although the relative regional cerebral blood volume values were mostly lower than those in the antegrade selective cerebral perfusion group. The total Histopathologic Damage Score (0, normal; 32, worst) in the intermittent retrograde cerebral perfusion group (8.0 +/- 0.6) was significantly lower than that in the conventional retrograde cerebral perfusion (17.5 +/- 1.7; P < .01) and circulatory arrest (25 +/- 1.0; P < 0.01) groups and was equivalent to that in the antegrade selective cerebral perfusion group (7.8 +/- 0.8; P = .9). CONCLUSION: Intermittent retrograde cerebral perfusion provides adequate neuroprotection by allowing high apparent diffusion coefficient values to be maintained.

Animals↗
PubMed2006

A surgical case of symptomatic coronary artery-pulmonary artery fistula.

We describe a 55-year-old female patient with multiple plexiform coronary artery-pulmonary artery fistulas, who presented with ischemic episodes accompanying an inversion of T wave on an electrocardiogram even though it was a small shunt size. The surgical procedure involved closure of the openings of the fistulas from inside the pulmonary trunk using cardiopulmonary bypass with additional ligations. Postoperative coronary angiogram revealed complete interruption of the coronary artery-pulmonary trunk fistulas resulting in complete resolution of the patient's chest symptoms.

Angina Pectoris↗
PubMed2006

Thoracoscopic surgery for pulmonary arteriovenous malformation.

We report 6 consecutive cases of pulmonary arteriovenous malformation in the periphery of the lung, which were treated successfully by thoracoscopy. Pulmonary wedge resection was performed with a linear cutting stapler to divide the feeding artery, drainage vein, and aneurysmal lesion of the arteriovenous malformation. Operative time ranged from 30 to 95 min (mean, 50 min). Bleeding was minimal in all cases. No major surgery-related complications were observed. Postoperative hospital stay was limited to one week except for one patient who had experienced a brain infarction preoperatively, caused by migration of an embolization coil. Histological examination confirmed that the arteriovenous malformation foci were completely removed. Pulmonary wedge resection through thoracoscopy is feasible as an alternative treatment for arteriovenous malformation located in the periphery of the lung parenchyma when pulmonary embolization therapy is difficult or unsuccessful.

Adult↗
PubMed2005

The angiotensin II type 1 receptor blocker candesartan attenuates graft vasculopathy.

OBJECTIVE: Transplant arteriosclerosis remains the major cause of graft failure after cardiac transplantation, although recent progress in immunosuppressive therapy has dramatically improved short-term survival of recipient. We investigated the effects of the angiotensin II type 1 receptor (AT(1)R) blocker candesartan on the development of transplant arteriosclerosis in a murine model of cardiac transplantation. MATERIALS AND METHODS: Hearts from DBA/2 (H-2(d)) mice were heterotopically transplanted into B10.D2 (H-2(d)) mice. Recipients were treated with oral administration of candesartan (1 mg/kg per day) or vehicle. Allografts were analyzed at 14 or 30 days after transplantation. RESULTS: Candesartan significantly reduced the development of coronary arteriosclerosis (intima/media ratio: 0.86 +/- 0.09 versus 0.57 +/- 0.10, P < 0.05), without affecting the degree of parenchymal rejection at 30 days. There was no significant difference in the expression of adhesion molecules and cytokines at 14 days. Candesartan significantly reduced the number of peripheral mononuclear cells that differentiated into smooth muscle-like cells in the presence of basic fibroblast growth factor and platelet-derived growth factor BB (27.1 +/- 3.1 versus 17.3 +/- 1.8 cells/HPF, P < 0.05). CONCLUSIONS: Angiotensin II may play a role in the pathogenesis of transplant arteriosclerosis. Blockade of AT(1)R might be effective as a prophylactic therapy for transplant arteriosclerosis along with conventional immunosuppressive drugs.

Angiotensin II Type 1 Receptor Blockers↗
PubMed2005

Age-associated aortic stenosis in apolipoprotein E-deficient mice.

OBJECTIVES: The present study was designed to assess aortic valve morphology and function in mice of advanced age. We also evaluated the potential contribution of bone-marrow-derived cells to the pathogenesis of aortic stenosis. BACKGROUND: Age-associated valvular degeneration is characterized by lipid accumulation, collagen deposition, and calcification containing smooth muscle-like cells and osteoblast-like cells. Cellular and molecular factors that mediate these changes remain unknown. METHODS: We extensively examined the aortic valves of senile wild-type and apolipoprotein E (ApoE)-/- mice with echocardiography. The aortic valves were analyzed by immunohistochemistry and electron microscopy. The bone marrow of wild-type and ApoE-/- mice was reconstituted with that of green fluorescent protein (GFP) or beta-galactosidase (LacZ) mice, which expressed GFP or LacZ ubiquitously. RESULTS: Transaortic flow velocity was correlated with age in wild-type and ApoE-/- mice. The aortic valves of old ApoE-/- mice showed sclerosis that resembled the pathology of human aortic stenosis. A significant number of GFP-positive cells (10.7 +/- 4.1%) in the sclerotic valves of ApoE-/- mice expressed alpha-smooth muscle actin, whereas most of the GFP-positive cells were identified as endothelial cells or macrophages in wild-type mice. There were bone-marrow-derived cells that were positive for osteoblast-related proteins near the sites of ectopic calcification. The sclerotic valves displayed frequent apoptotic cell death and chemokine expression. CONCLUSIONS: Senile ApoE-deficient mice display aortic valve sclerosis that is similar to that observed in humans. The sclerotic valves displayed frequent apoptotic cell death and chemokine expression. Smooth muscle-like cells observed in degenerative valves might derive, at least in part, from bone marrow.

Age Factors↗