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Biomedical subjects

Soichiro Kitamura

Publications and source records attributed to Soichiro Kitamura.

At least 109 records · Page 6Linked to original sources
PubMed2003

Direct cell-cell interaction of cardiomyocytes is key for bone marrow stromal cells to go into cardiac lineage in vitro.

OBJECTIVES: Cardiac environmental factors are thought to be powerful inducers in cardiomyogenic differentiation. In this study we simulated the cardiac environment using coculture and evaluated the cardiomyogenic differentiation in bone marrow stromal cells. METHODS: In group 1 only bone marrow stromal cells derived from transgenic mice expressing green fluorescent protein (GFP-BMCs) were cultured (n = 5). In group 2 cardiomyocytes from neonatal rats were grown on inserts, which we applied to culture dishes seeded with GFP-BMCs (n = 5). In group 3 GFP-BMCs were cocultured with cardiomyocytes on the same dishes (n = 5). We cultured these cells for 7 days and evaluated the synchronous contraction and the cardiomyogenic differentiation of GFP-BMCs by means of immunostaining. RESULTS: In groups 1 and 2 GFP-BMCs protein did not show any myogenic phenotypes for 7 days. In contrast, in group 3 some GFP-BMCs were incorporated in parallel with cardiomyocytes and revealed myotube-like formation on day 1. On day 2, some GFP-BMCs started to contract synchronously with cardiomyocytes. Myosin heavy chain-positive GFP-BMCs were recognized in 2.49% +/- 0.87% of the total GFP-BMCs on day 5 (P <.0001). Cardiac-specific troponin I-positive GFP-BMCs were in 1.86% +/- 0.53% of the total cells on day 5 (P <.0001). Atrial natriuretic peptide was also seen in GFP-BMCs, and connexin 43 was detected between GFP-BMCs and cardiomyocytes. CONCLUSIONS: Direct cell-cell interaction with cardiomyocytes was important for bone marrow stromal cells to differentiate into cardiomyocytes. This coculture was useful for simulating the cardiac environment in vitro for the research of cell transplantation in the heart.

Animals↗
PubMed2003

Early and late stroke after mitral valve replacement with a mechanical prosthesis: risk factor analysis of a 24-year experience.

OBJECTIVE: We evaluated risk factors for mortality and stroke after mechanical mitral valve replacement between May 1977 and December 2001. METHODS: Early and late mortality and stroke were assessed. Potential predictors of mortality and stroke were entered into a Cox proportional hazards model. Actuarial survival and freedom from stroke were determined by a log-rank test. RESULTS: Mitral valve replacement was performed in 812 patients. Concomitant procedures included left atrial appendage closure in 493 (61%) patients, tricuspid annuloplasty-replacement in 348 (43%) patients, maze procedure in 185 (23%) patients, plication of the left atrium in 148 (18%) patients, and other procedures in 151 (19%) patients. Five-year actuarial survival was 91.1% +/- 2.3%. Freedom from stroke at 8 years was significantly better in patients with sinus rhythm versus atrial fibrillation (P <.001). Ninety-nine percent of patients with mitral valve replacement combined with a maze procedure were free from stroke, whereas only 89% of patients with mitral valve replacement alone were free from stroke at 8 years after surgical intervention. Seventy-two patients had late stroke; sixty-five patients (90%) were in atrial fibrillation, and 47 (65%) patients had the left atrial appendage closed. Multivariate analysis showed that late atrial fibrillation (odds ratio, 3.39; 95% confidence interval, 1.72-6.67; P =.0001) and omission of the maze procedure (odds ratio, 3.40; 95% confidence interval, 1.14-10.14; P =.003) were the significant risk factors for late stroke. CONCLUSIONS: Persistent atrial fibrillation was the most significant risk factor for late stroke after mechanical mitral valve replacement. Restoration of sinus rhythm with a maze procedure nearly eliminated the risk of late stroke, whereas neither closure of the left atrial appendage nor therapeutic anticoagulation prevented this complication.

Adolescent↗
PubMed2003

Total arch replacement using antegrade selective cerebral perfusion with right axillary artery perfusion.

OBJECTIVE: Right axillary artery (AxA) perfusion, which can prevent cerebral embolism caused by retrograde perfusion via the femoral artery (FA), was used for selective cerebral perfusion (SCP) as well as cardiopulmonary bypass (CPB) in aortic arch repair. We review the outcome of aortic arch surgery using SCP with right AxA perfusion to clarify its efficacy. METHOD: Between 1998 and 2002, 120 patients underwent aortic arch repair using SCP with right AxA perfusion. The mean age was 69+/-10 years. Aneurysms were atherosclerotic in 79, dissecting in 32, and others in nine patients. Twenty of them (16.7%) required emergency surgery. CPB was initiated with right AxA and FA perfusion, and following SCP was established using right AxA and left common carotid artery perfusion. RESULTS: With right AxA perfusion, hospital mortality was 5.8%. Multivariate analysis showed only ruptured aneurysm was an independent determinant for hospital mortality. Permanent neurological dysfunction developed in one patient (0.8%), while seven (5.8%) suffered from temporary one. In univariate analysis, SCP time, stenosis of the carotid arteries, past history of cerebrovascular events, and atherosclerotic aneurysm were not related to temporary neurological deficits CONCLUSION: Right AxA perfusion in conjunction with SCP is a safe and useful alternative for brain protection in total arch replacement.

Adolescent↗
PubMed2003

The roles of vascular smooth muscle cells in the aortic wall thinness under prolonged continuous flow left heart bypass.

Aortic wall thinness was one of the most characteristic changes observed in experimental animals under prolonged continuous flow left heart bypass. The goal of this study was to determine the roles of smooth muscle cells in the vascular remodeling process in cases demonstrating aortic wall thinness under prolonged continuous flow left heart bypass. The aortic samples from three goats in which continuous flow left heart bypass was performed were subjected to histological and immunohistochemical analyses. After 4 weeks of observation, the pulse pressure in the goats under the continuous flow left heart bypass was clearly lower than that in the normal healthy goats. The aortic walls of these goats became thinner, an effect caused by the dilation of their internal diameter. These aortic smooth muscle cells maintained contractile formation due to the fact that they contained abundant alpha-smooth muscle actin (SMA) and smooth muscle myosin heavy chain (SMMS). These cells also synthesized redundant matrix metalloproteinase-2 and -9, and the ratio of the SMMS-positive to the SMA-positive area was significantly lower (0.76) than that observed in the control goat (1.00; P < 0.05). The smooth muscle cells demonstrated synthetic-dedifferentiated formation, which is one of the phenotypes of smooth muscle cell function. In conclusion, aortic wall thinness under prolonged continuous flow left heart bypass is caused by over-synthesis of matrix metalloproteinase in smooth muscle cells, and this refers the vascular remodeling process of the extracellular matrix.

Animals↗
PubMed2003

Design progress of the ultracompact integrated heart lung assist device--part 2: optimization of the diffuser vane profile.

The configuration of the vaned diffuser of the integrated heart lung assist device (IHLAD) has been revised to reduce mechanical blood trauma caused by the device. The flow visualization study of the flow near the diffuser vanes revealed the existence of a rotating stall which deteriorates the hydrodynamic performance of the device and augments the chance for blood cells to pass through the regions with intense shearing forces. Design changes of the diffuser included decrease in vane number from 7 to 5 and decrease in passage width from 3 mm to 2 mm. This design change was effective to suppress initiation of a rotating stall. Improvement of hydrodynamic performance and antihemolytic properties was confirmed with the newly designed configuration based on the flow visualization study.

Centrifugation↗
PubMed2003

Design progress of the ultracompact integrated heart lung assist device--part 1: effect of vaned diffusers on gas-transfer performances.

The integrated heart lung assist device (IHLAD) has been developed to overcome the problems of currently available extracorporeal membrane oxygenation devices. The integrated structure of a centrifugal blood pump and cylindrical bundle of polyolefin hollow-fibers has allowed a remarkably compact size for the device. This study deals with the design change of the IHLAD that added to the vaned diffuser between the impeller of the centrifugal pump and the hollow-fiber bundle with a view to enhancing the gas-transfer performance. Ex vivo gas-transfer performance tests were carried out, as well as hydrodynamic characteristics and hemolysis test using fresh goat blood. The oxygen transfer rate was generally improved, and the carbon dioxide removal rate was slightly improved. Intolerable amount of hemolysis (index of hemolysis= 0.177) was caused by the IHLAD, which must be resolved by improving the design in the future.

Animals↗
PubMed2003

Canine DNA array as a potential tool for combining physiology and molecular biology.

The combining of molecular biology and physiology is essential for the further development of cardiovascular medicine, and DNA microarray is a useful tool for assessing multiple gene expressions. A canine DNA microarray has been designed and tested. Approximately 60 cardiovascular-related genes were cloned from newly developed canine cDNA libraries and spotted on slides. Using the arrays, the gene expression profiles of canine myocardium in were analyzed 2 protocols: (1). ischemic myocardium by 50% reduction of the coronary blood flow, and (2). necrotic myocardium caused by coronary artery ligation. Three hours after 50% flow reduction, cardiovascular-related genes, including ecto-5'-nucleotidase, endothelin-1, PAI-1, and AT receptors, exhibited rapid alteration and there were many more altered genes than with the complete coronary occlusion. Irreversible ischemic damage without necrosis more strongly affected gene expressions in surviving myocardium than in fatally damaged myocardium. The canine DNA microarray is a useful tool for assessing the precise molecular events following changes in the pathophysiological conditions of the heart.

5'-Nucleotidase↗
PubMed2003

Current characteristics of infective endocarditis in Japan: an analysis of 848 cases in 2000 and 2001.

The Japanese Circulation Society appointed a committee to develop guidelines for the prevention, diagnosis and management of infective endocarditis in Japan. In making such guidelines, the committee required information on the current clinical characteristics of infective endocarditis and therefore performed a nationwide questionnaire survey of cases from 2000 and 2001. In total, data were received for 848 cases from 277 of the 817 hospitals surveyed. Mean age was 55+/-18 years and most patients were aged in their 50 s or 60 s; 53.9% of the patients had infective endocarditis of unknown origin (without any prior predisposing conditions or procedures) and the second most common etiology was post dental procedures. The most common microorganism was Gram-positive cocci (345 streptococci and 221 staphylococci) and methicillin resistant Staphylococcus aureus (MRSA) was found in 7.3%. Although more than 90% of cases with Streptococcus viridans were sensitive to penicillin G, 6.6% were resistant. All MRSAs were sensitive to vancomycin. The information obtained from the survey assisted in the making of the guidelines, which should become an indispensable tool for all clinicians.

Adult↗
PubMed2003

Percutaneous transluminal coronary angioplasty for anastomotic stenosis after coronary arterial bypass grafting in Kawasaki disease.

OBJECTIVES: We evaluated the efficacy of percutaneous transluminal coronary angioplasty for anastomotic stenosis after coronary arterial bypass grafting using the internal thoracic artery in patients with coronary arterial lesions due to Kawasaki disease. SUBJECTS AND METHODS: From July 1997 to April 2000, four boys and one girl underwent percutaneous transluminal coronary angioplasty for 6 anastomotic lesions following coronary arterial bypass grafting using the left or right internal thoracic artery. Progressive severe stenosis of the grafts in the follow-up angiograms after grafting, and evidence of ischemia, were regarded as indications for percutaneous transluminal coronary angioplasty. Age at coronary angioplasty ranged from 4.2 to 16.7 years, with a median of 6.9 years, while the interval from operation ranged from 0.3 to 3.0 years, with a median of 1.1 years. The diameter of the balloon catheter employed varied from 1.5 to 2.5 mm, and the pressure of inflation ranged from 8 to 16 atmospheres. RESULTS: The degree of stenosis decreased from 63 to 99%, with a median of 88%, to 0 to 40%, with a median of 17% immediately after angioplasty. A follow-up angiogram either 3 months or 1 year later revealed no restenosis in any patient. CONCLUSION: Percutaneous transluminal coronary angioplasty is a feasible and useful procedure for treating anastomotic stenosis following coronary arterial bypass grafting using the internal thoracic artery in patients with coronary arterial lesions due to Kawasaki disease.

Adolescent↗
PubMed2003

Early adaptation of the left internal thoracic artery as a blood source of y-composite radial artery grafts in off-pump coronary artery bypass grafting.

OBJECTIVE: Y-composite grafting with the radial artery (RA) is often used in off-pump coronary artery bypass grafting (OPCAB). However, the early flow reserve of the left internal thoracic artery (LITA) as a blood source of the Y-composite RA graft has not been delineated. METHODS: The size of the LITA was examined angiographically in 42 patients who underwent OPCAB using LITA and Y-composite RA grafting between June 2000 and February 2002. In these patients, the LITA was used as a blood source of the Y-composite RA graft. The mean patient age +/- SD was 67 +/- 8 years. The average number of d i stal anastomoses was 3.2 +/- 0.7. Total coronary revascularization was carried out in 34 patients with only LITA and Y-composite RA grafting. RA grafting was used for revascularization of the circumflex artery alone in 5 patients, for the right coronary artery system (RCS) alone in 6 patients, and for both the circumflex and the RCS in 23 patients. The average number of distal anastomoses using the RA was 1.9 +/- 0.7. Flow measurements of the proximal LITA were achieved intraoperatively with a transit-time flowmeter. The diameters of the LITA before and after the operation were measured angiographically. Intraoperative flow volume was correlated with the ratio of the LITA diameters before and after the operation. RESULTS: The mean flow rate of the LITA was 61 +/- 35 mL/min (range, 9-196 mL/min). The mean diameters of the LITA before and after the operation were 1.97 +/- 0.36 mm and 2.74 +/- 0.60 mm, respectively. The mean ratio of the LITA diameter after the opera t ion to that before the operation was 1.43 +/- 0.27. The intraoperative flow volume was positively correlated with the ratio of LITA diameters (r = 0.414; P =.006). CONCLUSION: These results demonstrate the early adaptation of the LITA as a blood source of the Y-composite RA graft in OPCAB and the rationale for using the LITA as a single blood source for total coronary artery revascularization.

Aged↗
PubMed2002

The effect of cryo-maze procedure on early and intermediate term outcome in mitral valve disease: case matched study.

BACKGROUND: The maze procedure is an effective way to treat atrial fibrillation (AF) associated with mitral valve disease. In a last several years, cryoablation was substituted for atrial incision in many reports to simplify the maze procedure. However, there has been no comparative study to delineate the feasibility of the use of cryoablation. METHODS AND RESULTS: We compared the early and intermediate-term results of the maze procedure including pulmonary venous isolation from the left atrium using cryoablation (CM) with our conventional (Kosakai) maze procedure (KM) including encircling incision around the orifices of pulmonary veins. One hundred and 10 pairs of patients were matched in the age, left atrial dimension >70 mm, duration of AF >0 years, previous cardiac surgery, mechanical valve implantation and concomitant aortic valve procedures. CM required significantly shorter cardiopulmonary bypass time (186+/-56 minute versus 214+/-47 minute, P=0.001) and aortic cross-clamp time (134+/-43 minute versus 144+/-37 minute, P=0.03) than KM with less chest tube drainage (590+/-353 mL versus 745+/-618 mL, P=0.02) for 12 hours after operation. The sinus rhythm restoration rate in CM group (85.4%) was comparable with KM group (86.4%) at discharge. In the late results, the actuarial freedom from recurrence of sustained AF at 3 years in CM group (97.7%) was not significantly (P=0.11) different from that in KM group (90.4%). The actuarial freedom from stroke at 3 years in CM group was 99.0%. CONCLUSION: The modification of the maze procedure including cryoablation for pulmonary venous isolation provided less aortic cross-clamp time and less amount of chest tube drainage with the comparable recovery and maintenance of sinus rhythm with KM. CM is a reliable and less invasive surgical option for the AF associated with mitral valve disease.

Atrial Fibrillation↗
PubMed2002

The impact of diabetic retinopathy on long-term outcome following coronary artery bypass graft surgery.

OBJECTIVES: We sought to assess the impact of diabetic retinopathy on long-term outcome among patients with diabetes and multivessel coronary artery disease (MVD) following coronary artery bypass graft surgery (CABG). BACKGROUND: For diabetics, CABG is the preferred revascularization strategy. Diabetic retinopathy is a major microvascular complication of diabetes, and its severity is directly related to total glycemic exposure. METHODS: We identified 223 consecutive diabetics with MVD whose retinae were evaluated within one year prior to CABG. The most recent ophthalmologic records up until the time of CABG were used to evaluate the severity of retinopathy. The median follow-up after CABG was 11.6 years. RESULTS: Diabetic retinopathy was a strong independent predictor of overall mortality (relative risk [RR], 4.0), and repeat revascularization (RR, 3.0). In separate analyses of diabetics with retinopathy and without retinopathy, predictors of mortality differed significantly between the two groups. Among diabetics with retinopathy, the presence of either preoperative renal (RR, 2.5) or ventricular (RR, 2.0) dysfunction had unfavorable effects on mortality, but the survival curves did not differ significantly according to the presence or absence of internal thoracic artery (ITA) grafting. In comparison, among diabetics without retinopathy, ITA grafting (RR, 0.34) had a beneficial effect on mortality, and the survival curves varied somewhat according to the presence or absence of renal or ventricular dysfunction. CONCLUSIONS: Diabetics with retinopathy had a distinct post-CABG course with a worse long-term prognosis, as compared with diabetics without retinopathy. Retina evaluation is useful for prediction of long-term prognosis and management of diabetics who need CABG.

Aged↗
PubMed2002

Plasma atrial natriuretic peptide concentration inversely correlates with left atrial collagen volume fraction in patients with atrial fibrillation: plasma ANP as a possible biochemical marker to predict the outcome of the maze procedure.

OBJECTIVES: We hypothesized that the plasma atrial natriuretic peptide (ANP) level reflects atrial degenerative change and may predict the outcome of the maze procedure. BACKGROUND: Although a larger preoperative left atrial dimension and longer duration of atrial fibrillation (AF) have been reported in patients with persistent AF than in those with sinus rhythm (SR), these individual factors were not enough to predict the outcome of the maze procedure. METHODS: Preoperative plasma ANP levels were measured in consecutive 62 patients who underwent the Kosakai's modified maze procedure. Moreover, we performed histological and molecular biological examinations in the resected left atrial tissues. RESULTS: The preoperative plasma ANP was lower in the AF group (n = 13) than it was in the SR group (n = 49) (p < 0.001). Multiple logistic regression analysis revealed that duration of AF and plasma ANP were independently associated with postoperative cardiac rhythm. Among 41 patients with a higher plasma ANP or shorter duration of AF than the median value, SR was restored in 95% of patients. In contrast, in 21 patients with a lower plasma ANP and a longer duration of AF than the median value, SR was restored only in 48% of patients. Histological examination revealed that the collagen volume in the left atrial tissue was higher in AF than it was in SR and inversely correlated with plasma ANP. In addition, the messenger RNA expressions of ANP, collagen type I and type III were lower in AF than they were in SR. CONCLUSIONS: These results suggest that a combination of plasma ANP and/or duration of AF may predict the success rate for the maze operation. Advanced atrial degenerative change may result in a decrease of atrial ANP secretion.

Aged↗
PubMed2002

Functional status in adolescents and adults with Fontan circulation.

OBJECTIVE: We determined functional status in adolescents and adults with Fontan circulation. METHODS: Functional status was studied in 25 patients surviving more than 2 years after the definitive procedure and currently no younger than 18 years old. Age at operation was 2 to 44 years old, and follow-up was 12 +/- 5 years. To achieve Fontan circulation, atriopulmonary connection was used in 14 patients, and total cavopulmonary connection in 11 patients. RESULTS: One patient undergoing atriopulmonary connection died suddenly 6 years after the Fontan procedure due to pulmonary thromboembolism. New York heart association functional status was class I in 23, and class II in 2, at the latest follow-up. Catheterization done 6.5 +/- 6.8 years after the Fontan procedure showed that systemic venous pressure was statistically higher (p = 0.019) in the atriopulmonary connection group (13 +/- 3 mmHg) than in the total cavopulmonary connection group (10 +/- 3 mmHg). Exercise tests in 19 patients showed reduced tolerance in all, with maximal oxygen intake being 24.4 +/- 5.1 ml/kg/min. Serum glutamic oxaloacetic transaminase and glutamic pyruvic transaminase were elevated above normal in 11 (44%). Arrhythmia was noted over longer terms in 4 patients undergoing atriopulmonary connection; in 3, atriopulmonary connection was converted to total cavopulmonary connection, and surgical intervention for atrial arrhythmia was successful. CONCLUSION: Although functional status in adolescents and adults with Fontan circulation was good, arrhythmia and liver dysfunction in such subjects could lead to morbidity.

Adolescent↗
PubMed2002

Bone marrow stromal cells contract synchronously with cardiomyocytes in a coculture system.

OBJECTIVES: Cell transplantation is a promising therapy for improving damaged heart function. Cardiac environmental factors are thought to be powerful differentiation inducers, but their effects are not well understood because of their in vivo nature. We simulated the cardiac environment using coculture and evaluated cardiomyogenic differentiation in bone marrow stromal cells and synchronous contraction with other cardiomyocytes. METHODS: Experiment 1. We evaluated the labeling efficiency, intensity, and pattern of green fluorescence in the transgenic mouse expressing green fluorescent protein-derived bone marrow stromal cells (GFP-BMCs) from initial plating through 8 weeks under fluorescent microscopy. Experiment 2. GFP-BMCs (10(5) cells) were cocultured with neonatal rat cardiomyocytes (10(5) cells). We also evaluated the incorporation, myogenic differentiation, and synchronous contraction of GFP-BMCs for 1 week under the same microscopy with a digital video camera. RESULTS: Experiment 1. All GFP-BMCs but red blood cells maintained green fluorescence from initial plating through 8 weeks. Experiment 2. Some GFP-BMCs were incorporated in parallel with cardiomyocytes and showed myotube-like formation on day 1. On day 2, GFP-BMCs started to contract synchronously with cardiomyocytes. GFP-BMCs formed colonies and maintained synchronous contraction on day 7. CONCLUSIONS: Direct cell-to-cell interaction with cardiomyocytes is essential for myogenic differentiation and synchronous contraction of bone marrow cells. This coculture is a simple tool for simulating the cardiac environment and evaluating phenotypic changes in vitro.

Animals↗
PubMed2002

Pulmonary venous obstruction after total cavopulmonary connection in heterotaxy.

Pulmonary venous obstruction is a rare complication after total cavopulmonary connection by intraatrial grafting. We experienced this complication in two patients. In one of them, a large prosthesis produced inflow obstruction of the dominant ventricle and was successfully replaced with a smaller tube. In the other patient, the intraatrial tube had become severely adherent to the common pulmonary venous orifice and was removed entirely. Conversion to an extracardiac Fontan circulation was later successfully established.

Blood Vessel Prosthesis Implantation↗
PubMed2002

Maze procedure and cor triatriatum repair.

A 39-year-old man had cor triatriatum (Lucas-Schmidt type IA) with severe mitral regurgitation and atrial fibrillation. We performed resection of the anomalous septum between the accessory chamber and the left atrium, and conducted mitral valve repair and the maze procedure. The patient regained sinus rhythm and normal pulmonary venous drainage to the left ventricle without mitral regurgitation. Histological examination demonstrated fibrotic myocardial structures in the anomalous septum. The maze procedure and complete excision of the anomalous septum proved to be effective surgical treatment for atrial fibrillation with cor triatriatum.

Adult↗