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Biomedical subjects

Yoshio Misawa

Publications and source records attributed to Yoshio Misawa.

At least 19 recordsLinked to original sources
PubMed2006

Simultaneously performed mitral valve replacement and Hartmann's operation for infectious endocarditis from Streptococcus bovis and rectal cancer.

In patients with surgical indications for both cardiac surgery and a malignant neoplasm, cardiac surgery should generally be performed first; however, in some cases simultaneous surgery is recommended. We report a case of infectious endocarditis of the mitral valve caused by Streptococcus bovis with rectal cancer. Blood cultures showed a rise in coagulase-negative S. bovis, and the source of infection was thought to be the rectal cancer. The patient presented with cerebral infarction prior to surgery, and the possibility of recurrence of an infarction was predicted. The tumor of the rectum was hemorrhagic, so to avoid hemorrhagic complications due to perioperative heparinization and anticoagulant therapy and to remove the source of infection, mitral valve replacement and a Hartmann's operation were performed simultaneously. The postoperative course was uneventful.

Colectomy↗
PubMed2005

Gene expression profiling of human atrial myocardium with atrial fibrillation by DNA microarray analysis.

BACKGROUND: Atrial fibrillation (AF) is the most frequently encountered arrhythmia in the clinical setting. However, a comprehensive investigation of the molecular mechanism of AF has not been performed. The aim of this study was to clarify transcriptional profiling of genes modulated in the atrium of AF patients using DNA microarray technology. METHODS: We obtained 17 fresh cardiac specimens, right atrial appendages, isolated from 10 patients with normal sinus rhythm and seven chronic AF patients who underwent cardiac surgery. Affymetrix GeneChip (Human Genome U95A) investigating 12,000 human genes was used for each specimen. Quantitative analysis of selected genes was performed by the real-time PCR method. RESULTS: The left atrial diameter in the AF group was greater than that in the sinus rhythm group. We could identify 33 AF-specific genes that were significantly activated (>1.5-fold), compared with the sinus rhythm group, including an ion channel, an antioxidant, an inflammation, three cell growth/cell cycle, three transcription such as nuclear factor-interleukin 6-beta, several cell signaling and several protein genes, and seven expressed sequence tags (ESTs). In contrast, we found 63 sinus rhythm-specific genes, including several cell signaling/communication such as sarcoplasmic reticulum Ca2+-ATPase 2, several cellular respiration and energy production and two antiproliferative or negative regulator of cell growth genes, and 22 ESTs. CONCLUSIONS: The present study demonstrated that about one hundred genes were modulated in the atria of AF patients. These findings suggest that these genes may play critical roles in the initiation or perpetuation of AF and the pathophysiology of atrial remodeling.

Adolescent↗
PubMed2005

Clinical features of third open-heart valve surgery at the same valve position.

OBJECTIVE: Recently, there has been an increase in case of repeated open-heart valve surgery and the clinical results of the second surgery are only slightly worse than those of the first surgery. However, clinical results of the third open-heart valve surgery at the same position are rarely reported. Clinical features of third open-heart valve surgery at the same position are discussed in this study. METHODS: Between 1995 and 2004, 16 patients underwent third open-heart valve surgery at the same valve position under cardiopulmonary bypass. The average age of the 16 patients, 12 females and 4 males, was 56 +/- 15 years. Clinical features of the 16 cases were retrospectively analyzed. RESULTS: Mechanical valve nonstructural dysfunction was the most common valve malady, followed by bioprosthetic valve dysfunction. The duration of surgery from skin incision to establishment of the cardiopulmonary bypass was 94 +/- 42 minutes. Myocardial ischemia time was 137 +/- 38 minutes and extracorporeal circulation time was 212 +/- 82 minutes. Early mortality was seen in 1 patient (6.25%) and late mortality was seen in 1 patient. CONCLUSION: Mechanical valve nonstructural valve dysfunction leads to repeated valve surgery. The clinical results of the third open-heart valve surgery at the same valve position are acceptable, and the mid-term survival is excellent.

Adult↗
PubMed2005

The CarboMedics prosthetic heart valve: experience with 180 implants.

At Jichi Medical School Hospital, three types of mechanical prosthetic valves (CarboMedics, Omnicarbon, Bicarbon) were used without randomization from 1991 to 2000. A retrospective study of valve replacements done between June 1991 and November 2000 utilizing 180 CarboMedics valves in 145 patients who had not previously undergone prosthetic valve replacement or aortic root and/or arch replacement was conducted to evaluate midterm patient outcomes to assess the future continuous use of CarboMedics valves. Women made up 47.6% of the patients and the mean age was 57.5 years (range 12-80 years). Preoperative New York Heart Association functional class was III or IV in 92.4% (134/145) of patients. Mean follow-up of 4.5 years (range 0-10.0 years) was 95.9% complete, with a total of 628 patient-years (PY). Early (within 30 postoperative days) mortality was 5.5% (8 of 145): 3 from hemorrhage, 3 from nonvalve-related heart failure, 1 from infection, and 1 from arrhythmia. There were 16 late deaths (2.54%/PY): 1 from hemorrhage, 4 from unknown causes/sudden death, 4 from nonvalve-related heart failure, and 7 from other noncardiac causes. A total of 121 patients (83.0%) were alive at the last follow-up, done in November 2000. The linearized death rate was 3.82%/year (including 1.11%/year for valve-related deaths). Linearized death rates from various causes were: bleeding, 0.96%/year; thromboembolism, 1.11%/year; thrombosis, 0.39%/year; perivalvular leak, 0.96%/year; endocarditis, 0%/year; hemolysis, 0%/year; and reoperation, 0.63%/year. No structural valve failure was observed. Comparative early mortality rates of valve replacement without aortic root replacement or arch replacement, excluding repeat valve replacement operations, in our institute, were 3.5% (12/307) for all valve types used contemporaneously, 2.6% (2/76) for Omnicarbon valves, and 2.3% (2/86) for Bicarbon valves. Although the CarboMedics valve had a rather high mortality rate of 5.5% (8/145) compared with the total early mortality rate of 3.5%, the low incidence of valve-related complications might support the continued use of the CarboMedics valve for valve replacement.

Adolescent↗
PubMed2005

Repair of infarcted myocardium mediated by transplanted bone marrow-derived CD34+ stem cells in a nonhuman primate model.

Rodent and human clinical studies have shown that transplantation of bone marrow stem cells to the ischemic myocardium results in improved cardiac function. In this study, cynomolgus monkey acute myocardial infarction was generated by ligating the left anterior descending artery, and autologous CD34(+) cells were transplanted to the peri-ischemic zone. To track the in vivo fate of transplanted cells, CD34(+) cells were genetically marked with green fluorescent protein (GFP) using a lentivirus vector before transplantation (marking efficiency, 41% on average). The group receiving cells (n = 4) demonstrated improved regional blood flow and cardiac function compared with the saline-treated group (n =4) at 2 weeks after transplant. However, very few transplanted cell-derived, GFP-positive cells were found incorporated into the vascular structure, and GFP-positive cardiomyocytes were not detected in the repaired tissue. On the other hand, cultured CD34(+) cells were found to secrete vascular endothelial growth factor (VEGF), and the in vivo regional VEGF levels showed a significant increase after the transplantation. These results suggest that the improvement is not the result of generation of transplanted cell-derived endothelial cells or cardiomyocytes; and raise the possibility that angiogenic cytokines secreted from transplanted cells potentiate angiogenic activity of endogenous cells.

Animals↗
PubMed2005

Anatomical repair of partially unroofed coronary sinus syndrome through the coronary sinus orifice.

A 15-year-old girl was admitted for repair of partially unroofed coronary sinus syndrome. A preoperative echocardiographic study disclosed the dilated coronary sinus and a draining blood flow into the right atrium from both the left atrium and the end of the coronary sinus. At surgery, the distal portion of the coronary sinus roof was found to be absent. The defect was repaired through the coronary sinus orifice with a patch. No electrophysiological conduction abnormalities developed and follow-up echocardiography showed neither residual shunts nor coronary sinus blood flow disturbances.

Adolescent↗
PubMed2004

Cardiac function-related gene expression profiles in human atrial myocytes.

To obtain insights into the molecular pathogenesis of heart failure in humans, we have analyzed the expression profiles of>12,000 genes in a total of 17 human specimens of right atrial myocytes. From this large data set, we here tried to identify gene clusters, expression level of which is correlated precisely with clinical parameter values of cardiac function. We could reveal that cardiac myocytes with normal sinus rhythm were clearly differentiated, in the point of view of gene expression, from those with atrial fibrillation. Further, an expression profile-based prediction of arrhythmia by a newly developed "weighted-distance method" could efficiently diagnose our samples. We could even construct calculation formulae for the values of left ventricular ejection fraction based on the expression level of selected genes. To our best knowledge, this is the first report to indicate that pumping ability of heart can be predicted by any measures of atrium.

Adolescent↗
PubMed2004

Successful weaning from cardiac extracorporeal membrane oxygenation by banding a hemodialysis arteriovenous fistula.

We report a case in which weaning from cardiac extracorporeal membrane oxygenation (ECMO) was achieved by temporarily occluding the hemodialysis arteriovenous fistula. A 68-year-old man with diabetic nephropathy underwent coronary artery bypass surgery, and cardiac ECMO was used to wean the patient from cardiopulmonary bypass. An ultrasonic flowmeter showed the arteriovenous flow to be over 750 ml/min, which can lead to increased preload on the weakened heart. On the sixth postoperative day, occlusion of the fistula by compression with a soft bandage provided the correct balance between myocardial reserve and shunt volume and hence facilitated successful weaning from cardiac ECMO.

Aged↗
PubMed2004

Transcriptional profile of genes induced in human atrial myocardium with pressure overload.

BACKGROUND: The molecular response of human myocardium to mechanical stimuli, particularly the difference between pressure or volume overload cardiac hypertrophy, remains incompletely defined. METHODS: We investigated the transcriptional profile of genes induced in human pressure- or volume-overloaded myocardium with DNA microarray technology. We used right atrial tissue from patients who underwent cardiac surgery. On the basis of pressure data and echocardiographic findings, the patients were divided into three groups: control group (n=3), pressure overload group (mean right atrial pressure of >7 mm Hg, n=3), and volume overload group (moderate or severe tricuspid regurgitation, n=3). Expression profiles of 2139 human genes were investigated with mRNA obtained from the samples. RESULTS: In the pressure overload group, expression of genes of cyclin-dependent kinase inhibitor 1A (CDKI1A, 11.7+/-3.1-fold vs. control), and mitogen-activated protein kinase phosphatase-1 (MKP-1, 26.2+/-2.1-fold) was significantly increased compared with those in control or volume overload group (P<0.05). The specificity of these gene expressions was confirmed by a quantitative "real-time" polymerase chain reaction (PCR) analysis. In addition, mechanical strain induced CDKI1A and MKP-1 protein expressions in neonatal rat cardiac myocytes in an amplitude-dependent manner. In contrast, transcripts of growth factors did not significantly increase. CONCLUSIONS: This study demonstrated that gene expressions of CDKI1A and MKP-1, but not growth factors, are induced in chronic pressure-overloaded myocardium. These findings suggest that suppressors of the cell cycle or cell proliferation may play a critical role in the pathophysiology of pressure overload.

Adolescent↗