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Biomedical subjects

R Muraoka

Publications and source records attributed to R Muraoka.

At least 19 recordsLinked to original sources
PubMed2001

Hyperamylasemia and subclinical pancreatitis after cardiac surgery.

Hyperamylasemia after cardiac surgery is common but typically causes no clinical concern because it consists mainly of the salivary isoenzyme. In this study we evaluated the incidence, source, and time course of postoperative hyperamylasemia with special attention to the possibility of subclinical pancreatitis. In 88 patients prospectively tested for serum amylase and lipase concentrations, elastase 1 activity, and amylase isoenzyme characteristics, 57 (64%) showed hyperamylasemia during the early postoperative period. In most cases early hyperamylasemia was not of pancreatic origin, but two patients were diagnosed with subclinical pancreatitis. Among the last 23 patients, 5 of 10 patients with early hyperamylasemia exceeding 1000 IU/L showed late hyperamylasemia on the seventh postoperative day, when it represented mainly the pancreatic isoenzyme. Lipase concentrations and elastase 1 activities were elevated in these cases. Late hyperamylasemia following cardiac surgery may be of pancreatic origin and indicative of subclinical pancreatitis, even if early hyperamylasemia was of salivary origin.

Adult↗
PubMed2001

Transmyocardial laser revascularization induced angiogenesis correlated with the expression of matrix metalloproteinases and platelet-derived endothelial cell growth factor.

OBJECTIVE: Transmyocardial laser revascularization (TMLR) has been widely evaluated as a treatment for ischemic myocardium. However, its mechanism remains unclear. One mechanism is angiogenesis. This study examines the relationship between TMLR and angiogenesis from the viewpoint of matrix metalloproteinases and platelet-derived endothelial cell growth factor. METHODS: The left anterior descending coronary artery (LAD) was ligated permanently in 12 beagle dogs. TMLR was accomplished in six of the 12 dogs using a carbon dioxide laser. No laser treatment was done in the six control dogs. Two weeks after the initial operation, dogs were euthanized and transmural samples (each of approximately 0.5 g) were cut from the center of the infarcted LAD territory, right ventricular wall, left circumflex artery perfuse area and interventricular septum except the LAD perfuse area. They were snap-frozen in liquid nitrogen for matrix metalloproteinases and platelet-derived endothelial cell growth factor activity analysis. Hematoxylin and eosin staining, double immunohistologic staining with anti-proliferating cell nuclear antigen and von Willebrand factor antibody, and immunohistologic staining with antibody against platelet-derived endothelial cell growth factor were performed for histologic studies. The activities of matrix metalloproteinases were examined by gelatin zymography. The activity of platelet-derived endothelial cell growth factor was examined by a spectrophotometric method. RESULTS: The channels were found to be infiltrated with granulation tissue and fibrosis. In the laser group, the active matrix metalloproteinase-2 and platelet-derived endothelial cell growth factor activity in the area of the left anterior descending coronary artery was significantly higher than in the control group (P<0.0001 and P=0.037, respectively). Within the channel remnants or close to these areas, the number of von Willebrand factor positive microvessels and proliferating cell nuclear antigen with correlating von Willebrand factor positive microvessels were significantly higher than in the control group (P=0.001 and P=0.0006, respectively). These increases in microvessels significantly correlated with the expression of matrix metalloproteinases and platelet-derived endothelial cell growth factor. CONCLUSION: Based on these findings it was concluded that transmyocardial laser revascularization induced angiogenesis correlated with the expression of active matrix metalloproteinases-2 and platelet-derived endothelial cell growth factor.

Animals↗
PubMed2000

Primary aortosigmoid fistula treated by descending thoracic aortofemoral bypass.

Primary aortoenteric fistula is a rare disease with a fatal outcome unless it is diagnosed accurately and treated surgically. We present an elderly patient with primary aortosigmoid fistula confirmed by endoscopy. Descending thoracic aortofemoral bypass was performed and the aortoiliac aneurysm and sigmoid colon were then resected in continuity. The patient maintains a good quality of life 6 years after the operation with good graft patency and no sign of graft infection.

Aged↗
PubMed1999

Tumor angiogenesis, apoptosis, and p53 oncogene in stage I lung adenocarcinoma.

The purpose of this study was to clarify which factors are important as predictors not only of patient survival but also of hematogenic metastasis in 15 patients with stage I lung adenocarcinoma who underwent curative operation. The relationship between tumor angiogenesis, apoptosis, and p53 oncogene was also studied. A total of 15 patients were divided into two groups: surviving group (n = 7) and nonsurviving (metastasis) group (n = 8). We studied the medical charts, operative records, pathologic reports, and tumor specimens taken at surgical resection. We measured the apoptotic index using the ApopTag kit and the intratumoral microvessel count using an anti-CD34 monoclonal antibody. In addition, immunohistochemical staining for the expression of p53 was conducted simultaneously. The clinicopathological characteristics, including age, sex, tumor size (pT), and histological differentiation, were not significantly different between the surviving and the nonsurviving group. The microvessel count was significantly higher in nonsurviving group than in the surviving group. The apoptotic index and the expression of p53 was not significantly different between the two groups. An inverse correlation between the apoptotic index and microvessel count, and a positive correlation between the expression of p53 and microvessel count, were observed. Angiogenesis may be an important prognostic factor in patients with stage I lung adenocarcinoma.

Adenocarcinoma↗
PubMed1999

Postoperative inflammatory reactions of impregnated Dacron grafts.

The clinical efficacy of Dacron grafts that are impregnated with collagen or gelatin has been well demonstrated, but inflammatory reactions during the first few postoperative weeks have been reported. We experienced two patients, an 87-year-old man with a reconstruction of an abdominal aorta and a 7-year-old boy with a reconstruction of aortic arch with a collagen-impregnated graft (Hemashield), who continued to demonstrate a high fever with a high serum level of C-reactive protein (CRP) and immunoglobin for more than 5 months. The body temperature, the white blood cell (WBC) counts, and the serum level of CRP were compared on the seventh and 14th postoperative day among the 37 patients who underwent a reconstruction of either a thoracic or abdominal aorta using the Hemashield graft (Hemashield group) and a nonimpregnated graft (control group) in our hospital. An elevation of body temperature above 38 degrees C was seen 29% of the patients in the Hemashield group and 0% in the control group. No significant differences were seen in the WBC counts, but the serum level of CRP was significantly higher on the 14th postoperative day in the Hemashield group. We should therefore pay careful attention to inflammatory reactions after the implantation of the impregnated grafts.

Aged↗
PubMed1999

Experimental determination of the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass.

This study investigated the safe minimum perfusion flow rate for low-flow hypothermic cardiopulmonary bypass in a canine model. The adequacy of cerebral oxygenation was determined from the adenosine concentration, the oxygen saturation of cerebral venous blood and brain oxyhemoglobin level. In experiment 1, nine beagles were cooled on bypass to a nasopharyngeal temperature of 18 degrees C and the perfusion flow rate was reduced in a stepwise fashion every 30 min from 100 to 50, 30, 20 and 10 ml/kg per min. In experiment 2, six beagles were cooled on bypass as in experiment 1, and flow was maintained at 30 ml/kg per min for 120 min. At a perfusion flow rate of 30 ml/kg per min, adequate cerebral oxygenation was maintained for 120 min. In contrast, perfusion flow rates of 20 and 10 ml/kg per min were associated with cerebral ischemia.

Adenosine Triphosphate↗
PubMed1999

Low-potassium University of Wisconsin solution for cardioplegia: improved protection of the isolated ischemic neonatal rabbit heart.

Recovery of cardiac function and high-energy phosphates following ischemia and reperfusion were determined for hearts perfused with low potassium University of Wisconsin solution, high potassium University of Wisconsin solution, St Thomas' solution, or subjected to hypothermia alone. Isolated hearts were arrested for either 3 h at 15 degrees C or 6 h at 20 degrees C (n = 7 for each group) with one of the four solutions and then reperfused. Aortic flow after ischemic arrest at 20 degrees C was 40.3 +/- 13.3%, 79.3 +/- 10.0%, 64.3 +/- 11.9% and 43.9 +/- 15.9% of control values for high potassium University of Wisconsin solution, low potassium University of Wisconsin solution, St Thomas' solution and hypothermia alone, respectively. Similar results were observed in hearts subjected to ischemic arrest at 15 degrees C. Myocardial adenosine triphosphate and creatine phosphate after reperfusion tended to be higher in the low potassium University of Wisconsin solution group. It is concluded that low potassium University of Wisconsin solution may provide reliable cardioplegia during surgery that requires prolonged cardiac arrest in neonates and infants.

Adenosine↗
PubMed1999

Changes of angiogenesis and tumor cell apoptosis during colorectal carcinogenesis.

Activation of the angiogenic process occurs during tumorigenesis, as does disturbance of cell proliferation and apoptosis. Seeking a potential correlation, we investigated tumor cell apoptosis, proliferation, and angiogenesis in the adenoma-carcinoma sequence of colorectal carcinogenesis using an in situ apoptosis detection kit and MIB-1 and anti-CD34 antibodies in 27 adenomas with low dysplasia, 17 adenomas with high dysplasia, and 26 carcinomas in adenoma, as well as assessed p53 and bcl-2 expressions. The results showed that the potential for apoptosis was augmented, paralleling the increment of proliferation, in adenomas with low dysplasia but diminished when adenomas progressed from low dysplasia to high dysplasia and cancer. A gradual increment of microvessel density was observed during the progression with an increase during transition from low dysplasia to high dysplasia and cancer. Correlation coefficient test showed an inverse correlation between apoptotic index and microvessel density when all of the lesions were taken into account. No apparent impact of aberrant p53 on angiogenesis or bcl-2 on apoptosis was observed in this study. These results suggest that the angiogenesis initiates during transition from low dysplasia to high dysplasia and cancer, which may, in turn, contribute to the reduction of tumor cell apoptosis during colorectal carcinogenesis.

Adenocarcinoma↗
PubMed1998

Intermittent hepatic pedicle clamping reduces liver and lung injury.

BACKGROUND: Temporary occlusion of the hepatic hilum is used to control hemorrhage during liver resection, but can result in widespread organ dysfunction. MATERIALS AND METHODS: Adult male Sprague-Dawley rats were subjected to either continuous (Group C) or intermittent (Group R) hepatic ischemia. The total ischemia time (60 min) was divided into four 15-min periods in Group R. Blood and lung tissue specimens were collected 2 h after the induction of ischemia (early phase), and 24 h after the termination of ischemia (late phase). Plasma lactate dehydrogenase (LDH), aspartate aminotransferase (AST), alanine aminotransferase (ALT), tumor necrosis factor-alpha (TNF-alpha), and interleukin-6 (IL-6) concentrations were measured. Histologic sections were studied using hematoxylin and eosin, as well as naphthol AS-D chloroacetate esterase techniques. RESULTS: In the early phase, LDH, ALT, TNF-alpha, and IL-6 concentrations were significantly higher in Group C than in Group R. Pulmonary septal thickening and polymorphonuclear leukocyte infiltration were less severe in Group R than in Group C. These differences were significant in the late phase. CONCLUSIONS: Intermittent hepatic pedicle clamping reduces the ischemia-reperfusion injury not only to the liver but also to the lungs. This technique may improve the outcome in patients undergoing liver resection.

Alanine Transaminase↗
PubMed1998

Platelet-derived endothelial cell growth factor/thymidine phosphorylase expression correlated with tumor angiogenesis and macrophage infiltration in colorectal cancer.

To clarify whether platelet-derived endothelial cell growth factor/thymidine phosphorylase (PD-ECGF/TP) expression in both tumor cells and stromal cells has independent or synergistic effects on tumor angiogenesis and progression and to explore a possible regulator for PD-ECGF/TP expression, immunohistochemical staining was conducted on 148 specimens of colorectal cancer. The microvessel count was significantly correlated with the extent of PD-ECGF/TP expression. Macrophage infiltration in tumors with positive TP was significantly higher than in tumors with negative TP (P < 0.001). The Cox model showed that PD-ECGF/TP expression was an independent prognostic factor, although the microvessel count had a stronger value in determining the patient prognosis.

Adenocarcinoma↗
PubMed1998

Relationship between flushing pressure and nitric oxide production in preserved lungs.

BACKGROUND: Nitric oxide (NO) is considered to be one of the endogenous inhibitory factors of ischemic reperfusion injury. In this study, the NO-producing ability of the preserved lung, flushed at various pulmonary artery pressures (flushing pressure), was studied during reperfusion using an ex vivo rabbit lung perfusion model. METHODS: The lungs were flushed with 200 ml of preservation solution with flushing pressures adjusted to 15, 15, 20, and 25 mmHg for groups 1, 2, 3, and 4, respectively (n=5 in each group). In the control group (group 1), the heart-lung block was harvested after flushing and the lungs were assessed without preservation. In the other groups, the harvested blocks were preserved at 8 degrees C for 24 hr and reperfused with homologous blood for pulmonary functional assessment. Pulmonary function was assessed by measuring mean airway pressure, mean pulmonary arterial pressure, partial oxygen tension of pulmonary venous effluent blood, and pulmonary wet-dry weight ratio. The sequential changes in the concentration of NO-related substances (NO-RS) in the serum of reperfused blood were also measured by chemiluminescence. RESULTS: During reperfusion, biphasic increases in NO-RS were observed in all groups. In groups 3 and 4, the increases in NO-RS were significantly lower than those of groups 1 and 2, and pulmonary function deteriorated. CONCLUSION: These data suggest that in order to maintain the endogenous NO-producing ability of preserved lung, the flushing pressure must be less than 20 mmHg.

Animals↗
PubMed1998

[Removal of retained transvenous pacemaker electrodes under cardiopulmonary bypass].

A case of breakage and removal of a retained transvenous pacemaker electrode is described. A 22-year-old woman with complete A-V block underwent implantation of a transvenous pacemaker system on the left anterior chest wall in 1989. Three years later, a new generator was implanted on the right chest wall because of local infection of the pacemaker pockets. The old electrodes could not be removed and were left in place. Beginning in 1995, the patient complained of anterior chest pain. A chest roentgenogram revealed that one of the pacemaker electrodes had broken at the right costoclavicular ligament and a fragment was floating in the superior vena vava. The retained electrodes were removed under tot cardiopulmonary bypass. These electrodes had become firmly encased with fibrous tissue within the right ventricle and atrium, but they were easily removed under direct vision duting complete cardiac arrest. The postoperative course was uneventful and the patients had no further complaint.

Adult↗
PubMed1998

Effects of depletion of leukocytes and platelets on cardiac dysfunction after cardiopulmonary bypass.

BACKGROUND: This study examined the effects of the depletion of leukocytes and platelets from circulated blood on cardiac function after cardiopulmonary bypass in 37 patients who underwent coronary artery bypass grafting or aortic valve replacement. METHODS: Leukocytes and platelets were removed continuously using a blood cell separator, beginning immediately after the start of the operation and ending 1 hour after the release of the aortic cross-clamp in 19 patients (LPD group), but not in the remaining 18 patients (control group). Blood cell counts and levels of thromboxane B2, 6-keto-prostaglandin F1alpha, leukocyte elastase, complements C3a and C4a, thrombin-antithrombin III complex, and D-dimer were determined periodically during and after the operation. The cardiac index, the difference between the central and peripheral core temperatures, and the doses of catecholamines and vasodilators required to support the circulation in the early postoperative period also were assessed. RESULTS: Leukocyte and platelet counts and levels of leukocyte elastase, thromboxane B2, thromboxane2/6-ketoprostaglandin F1alpha, thrombin-antithrombin III complex, and D-dimer were significantly lower in the LPD group than in the control group before and after the release of the aortic cross-clamp and during the perioperative period. There were no significant differences in the levels of 6-keto-prostaglandin F1alpha or complements C3a and C4a between the two groups. The catecholamine dose was significantly lower in the LPD group than in the control group (1.1 +/- 2.5 versus 5.0 +/- 5.2 mg/kg, respectively). Fewer patients required the use of nitroprusside as a vasodilator in the LPD group than in the control group (1/19 versus 12/18, respectively). CONCLUSIONS: The depletion of leukocytes and platelets using a blood cell separator prevents the deterioration of cardiac function after cardiac operations using cardiopulmonary bypass.

6-Ketoprostaglandin F1 alpha↗
PubMed1998

Tumor angiogenesis as a prognostic marker in operable non-small cell lung cancer.

BACKGROUND: Recent evidence suggests that tumor angiogenesis is associated with patient outcome in a number of malignancies. However, little is known about the significance of tumor microvessel density as evaluated by an anti-CD34 antibody in patients with lung cancer. METHODS: Tumor tissues were obtained from 101 patients with operable non-small cell lung cancers. Immunohistochemical detection of tumor-associated microvessels was performed using anti-CD34 antibodies directed against endothelial markers. Average counts of the three most vascular areas on a X200 field were recorded. RESULTS: Staining for CD34 was easy to interpret because of specific and minimal background staining. The Kaplan-Meier method showed a statistically significant difference between the microvessel count and overall survival. The microvessel count was identified as the only significant and independent prognostic marker. In both univariate and multivariate analyses, the microvessel count was significantly related to the development of hematogenous metastasis but failed to associate with the development of nodal metastasis. CONCLUSIONS: Tumor vascularity is an independent prognostic factor and important for the development of hematogenous metastasis.

Adult↗
PubMed1998

Prolongation of total permissible circulatory arrest duration by deep hypothermic intermittent circulatory arrest.

OBJECTIVE: We determined whether the duration of permissible circulatory arrest could be prolonged by deep hypothermic intermittent circulatory arrest. METHODS: Twenty-five beagles were cooled on bypass to 18 degrees C to initiate deep hypothermia that was maintained for 3 hours. Five protocols were then studied: group 1, uninterrupted bypass during hypothermia; group 2, arrest for 40 minutes during hypothermia; group 3, arrest for 60 minutes during hypothermia; group 4, arrest for 80 minutes during hypothermia; and group 5, intermittent circulatory arrest, consisting of six cycles of 20 minutes of arrest followed by 10 minutes of systemic recirculation during hypothermia (total, 120 minutes of arrest). The oxyhemoglobin concentration in the brain was measured with near infrared spectrophotometry. RESULTS: In groups 2, 3, and 4, the oxyhemoglobin concentration in the brain decreased continuously after arrest, finally reaching a plateau after 24.9 +/- 1.2 minutes. This finding suggested that the available cerebral oxyhemoglobin was depleted. In contrast, the available cerebral oxyhemoglobin was not depleted during hypothermic intermittent arrest in group 5. The mitochondrial respiratory control index was significantly lower in group 4 than in the other groups (p < 0.05). However, there were no significant differences in the respiratory control index for groups 1, 2, 3, and 5. Moreover, the formation of brain edema was significantly lower in group 5 than in the other groups (p < 0.05). CONCLUSIONS: These results indicate that deep hypothermic intermittent arrest can increase the duration of total permissible circulatory arrest and will be a useful modality when prolonged arrest is anticipated.

Animals↗