Biomedical subjects

Kunihide Nakamura

Publications and source records attributed to Kunihide Nakamura.

12 recordsLinked to original sources

PubMed2006

Adrenomedullin in mast cells of abdominal aortic aneurysm.

OBJECTIVES: Produced by vascular walls, adrenomedullin (AM) exerts antifibrotic actions in the process of cardiovascular remodeling. The purpose of this study was to examine the pathophysiological role of AM in the development of human abdominal aortic aneurysm (AAA). METHODS AND RESULTS: Immunohistochemical analyses revealed that vascular smooth muscle cells in the media were positive for AM in the early stage of atherosclerotic aorta. Intense immunoreactivity was observed in mast cells of the outer media and adventitia of AAA, and the number of mast cells was greater (p < 0.01) in AAA than in atherosclerotic aorta without any aneurysmal change. To determine the role of AM in mast cells, we examined cultured human mast cell leukemia line-1 (HMC-1) and fibroblasts isolated from AAA patients. Cultured HMC-1 cells were found to express preproAM gene and release AM peptide into the cultured media. When assessed by collagenase-sensitive [3H]proline incorporation and procollagen type I C-peptide secretion, collagen synthesis in co-culture of HMC-1 and the fibroblasts was reduced by 10(-6) mol/L synthetic AM, while conversely, it increased following blockade of the action of endogenous AM with 10 microg/mL anti-AM monoclonal antibody. CONCLUSION: The present study suggests an anti-fibrotic role for AM released from mast cells, providing new insight into the biological actions of mast cell-derived AM in the development of AAA.

Adrenomedullin↗

PubMed2006

Clinical analysis of acute type A intramural hematoma: comparison between two different pathophysiological types.

BACKGROUND: Type A intramural hematoma (IMH) has two different etiologies, which are rupture of vasa vasorum and penetrating atherosclerotic ulcer (PAU); however, it is difficult to know which is the initiating event. METHODS: Between January 1993 and August 2004, 28 patients of acute type A IMH were treated in our department and were divided into two groups, 20 patients with IMH probably caused by rupture of vasa vasorum (non-PAU group) and 8 patients with IMH probably caused by PAU (PAU group), according to pathologic specimen and atherosclerotic findings on computed tomography. Background factors, radiographic findings, and prognosis were analyzed retrospectively. RESULTS: Surgery was performed in 15 patients (75%) in non-PAU group and 4 patients (50%) in PAU group during the first admission. Late progression was noted in 3 patients, and operation was required. Finally, operation was performed in 22 patients (78.6%). The history of myocardial infarction (p = 0.026) and chronic renal failure (p = 0.026) were more associated with PAU group than with non-PAU group. Ascending aortic diameter at the onset was significantly larger in non-PAU group (50.3 +/- 6.6 mm) than in PAU group (43.9 +/- 9.0 mm; p = 0.046), and there were significantly more ulcer lesions in PAU group (1.9 +/- 0.4) than in non-PAU group (1.1 +/- 0.4; p = 0.0004). There was no significant difference in long-term survival rates between them. CONCLUSIONS: The PAU group patients have more coexisting atherosclerotic diseases and multiple aortic ulcer lesions with significantly mild ascending aortic dilatation compared with non-PAU group patients.

Age Factors↗

PubMed2006

[Complete resection of the invasive thymoma combined with replacement of aortic arch and pneumonectomy].

A 68-year-old male was found an abnormal shadow on chest X-ray and was diagnosed as thymoma by computed tomography (CT)-guided needle biopsy. As the tumor invaded the aortic arch, left main pulmonary artery and the lung, thymectomy combined resection of the surrounding tissues was performed for the complete resection. The aortic arch was replaced with cardiovascular graft under cardiopulmonary bypass, with the aid of selective cerebral perfusion. The left pneumonectomy was performed because the tumor invaded to the left main pulmonary artery and to the lung parenchyma. Masaoka stage III and histologic type B2 were diagnosed according to the World Health Organization classification. The patient has been well without recurrence or metastasis after the surgery for 2 years. A complete resection of the thymoma invaded to great vessels should be performed to expect for the good curability and prognosis.

Aged↗

PubMed2005

Selective delayed management of blunt traumatic left common carotid artery injury using hypothermic circulatory arrest.

Most traumatic carotid artery aneurysms occur at or close to its bifurcation, and traumatic aneurysm of the intrathoracic carotid arteries are rare. We describe a case of false aneurysm at the origin of the left common carotid artery (LCCA) after blunt trauma. A 53-year-old man suffered a blow from a broken steel plate, which flew from a working concrete crusher over his neck when he looked down the machine. Chest computed tomography revealed aneurysm of the LCCA, and aortic arch arteriography demonstrated a false aneurysm of about 3 x 5 cm at the origin of the LCCA, with loss of arterial continuity and abnormal tortuosity above the aneurysm. An ascending aorta to LCCA bypass graft was placed during the cooling period of cardiopulmonary bypass, and mattress sutures were placed in the normal aorta to close the origin of the LCCA under hypothermic circulatory arrest because of the extreme danger of dissection. The LCCA was transected partially at its origin from the aorta. We speculated that the direct lifting force which caused the carotid artery to move upward might produce a tear at the junction of the LCCA and the aortic arch.

Accidents, Occupational↗

PubMed2005

Predictor of neurologic dysfunction after elective thoracic aorta repair using selective cerebral perfusion.

OBJECTIVES: This study was undertaken to determine the factors that influence postoperative neurological dysfunction after selective cerebral perfusion (SCP). DESIGN: From 1995 to August 2004, 60 patients were evaluated for the presence of cerebro-vascular disease (CVD), and then underwent thoracic aortic operations using SCP. Perioperative factors were evaluated by multivariate analyses. RESULTS: Hospital mortality rate was zero. Sixteen patients (26.7%) proved to have CVD. Permanent neurological dysfunction (PND) appeared in three patients (5.0%) and transient neurological dysfunction (TND) in two (3.3%). Univariate analysis revealed superficial temporal artery (STA) pressure during SCP (p = 0.0410) to be a significant risk factor for PND. Variables that achieved values of p < 0.2 (aortic cross-clamp time, presence of CVD, old cerebral infarction, presence of clots or atheroma) were examined with multivariate analysis and the presence of CVD (p = 0.038) and STA pressure during SCP (p = 0.032) were independent risk factors for PND. Multivariate analysis for TND did not show any risk factor. CONCLUSIONS: The presence of CVD was indicated as an independent risk factor for PND after thoracic aortic operations using SCP.

Aged↗

PubMed2004

Popliteal artery pseudoaneurysm caused by osteochondroma.

A 49-year-old man with asymptomatic osteochondroma was found to have a pseudoaneurysm of the left popliteal artery. An angiography showed a popliteal artery pseudoaneurysm adjacent to a femoral osteochondroma. The osteochondroma was excised and the popliteal artery containing the tear was also excised by end-to-end anastomosis. Vascular complication of osteochondroma is extremely rare. Paul reported the first case of a popliteal artery pseudoaneurysm due to osteochondroma in 1953. A computerized literature search revealed 40 additional cases reported in English, providing sufficient detail to allow comparison. The average age of the patients was 22.6 years (range 9-51) and most cases identified involved males (30 of 41, 73%). Most pseudoaneurysm were located in the popliteal artery. This report discusses the authors' experience with this disorder and a review of the literature in English.

Aneurysm, False↗

PubMed2004

Comparison of pulsatile and non-pulsatile cardiopulmonary bypass on regional renal blood flow in sheep.

OBJECTIVE: The purpose of the present study was to evaluate the effects of pulsatile cardiopulmonary bypass (CPB) on sheep regional renal blood flow by comparing pulsatile and non-pulsatile perfusion at two different flow rates. DESIGN: Seven female Suffolk sheep were used and the animals were perfused with pulsatile and non-pulsatile CPB at flow rates of 60 and 100 ml/min/kg. Regional renal blood flow was measured by the colored microsphere method. General linear model ANOVA was performed to analyze the data. RESULTS: Regional renal blood flow was significantly higher in both outer and middle cortices of pulsatile CPB compared with non-pulsatile CPB (outer cortex: pulsatile CPB, 381+/-192 ml/min/100 g, non-pulsatile CPB, 255+/-151 ml/min/100g, p=0.002; middle cortex: pulsatile CPB, 239+/-114 ml/min/100 g, non-pulsatile CPB, 176+/-80 ml/min/100 g, p=0.02). The increase of flow rate from 60 to 100 ml/min/kg improved renal cortical blood flow significantly. CONCLUSION: The regional renal blood flow was significantly higher in both outer and middle cortices of pulsatile CPB compared with the non-pulsatile CPB.

Animals↗

PubMed2003

Influence of heparin dosage on hemostasis under combined use of Nafamostat mesilate during deep hypothermic circulatory arrest.

OBJECTIVE: Nafamostat mesilate (NM) is a guanidine acid derivative which is synthesized in Japan as an antifibrinolytic drug. It has been successfully used to decrease blood loss and blood product requirement in cardiac operations. As there have been some reports that insufficient heparinization might induce the coagulopathic state in aprotinin-treated patients undergoing deep hypothermia and circulatory arrest (DHCA), we have reviewed 16 consecutive patients who underwent total aortic arch replacement using DHCA and the associated use of NM. METHODS: The patients were divided into two groups; a Normal-dosage Group (n = 8) who received 3 mg/kg of heparin, and a Low-dosage Group (n = 8) who received 1.5 mg/kg of heparin. The Celite-activating clotting time was maintained at longer than 1,000 seconds in both groups. Blood loss, transfusion requirements and the volume of postoperative mediastinal tube drainage were compared between the two groups. RESULTS: We observed no adverse effects of NM and no significant difference in transfusion requirements between both groups. There was a significant difference in blood loss during the operation between the two groups (p < 0.05) (Low-dosage Group 1,973 +/- 959 ml vs Normal-dosage Group 1,059 +/- 704 ml). CONCLUSIONS: NM was a safe antifibrinolytic drug. Adequate heparinization was necessary to reduce hemorrhage in patients undergoing aortic arch replacement using DHCA and the associated use of NM.

Aged↗

PubMed2003

Surgical resection of right atrial neurilemoma extending to pulmonary vein.

An asymptomatic cardiac neurilemoma was found in a 33-year-old woman. The tumor was on the anterior surface of the right atrium extending to the right upper pulmonary vein across the interatrial groove. The tumor was resected completely and right atrium, interatrial septum, left atrium and right superior pulmonary vein were reconstructed with cardiopulmonary bypass. The patient recovered uneventfully and had no recurrence 1 year after the operation. We reviewed ten reported cases of cardiac neurilemoma, including our patient.

Adult↗

PubMed2002

Giant cell tumor of the rib.

In a rare case of a giant cell tumor of rib origin, a 25-year-old woman to be evaluated for an abnormal mass shadow in chest radiography was strongly positive in a tuberculin skin test, but showed no evidence of active tuberculosis. Chest computed tomography showed a heterogeneous mass originating in the posterior end of the right fourth rib and containing multiple calcifications and cystic lesions. Magnetic resonance imaging showed a high signal intensity with low signal intensity areas. Bone scintigraphy showed an abnormal marked accumulation at the tumor site. A thoracoscopic examination was conducted prior to complete tumor resection, including the fourth rib and related muscles. The pathological diagnosis returned was a giant cell tumor of the bone. The patient did not undergo chemotherapy or radiotherapy, and remains well, and tumor-free at 6 months after surgery.

Adult↗

PubMed2002

Nitric oxide inhalation prompts weaning from the right ventricular assist device: evaluation under continuous-flow biventricular assistance.

OBJECTIVE: The objective of this study was to investigate the effect of nitric oxide on the recovery of right heart function under global ischemia with a continuous-flow biventricular assist device support. METHODS: Fifteen piglets were divided into three groups: continuous-flow biventricular assist support only (control group), global ischemia with continuous-flow biventricular assist support (ischemia only group), and global ischemia with continuous-flow biventricular assist support plus nitric oxide inhalation (nitric oxide group). Two continuous-flow pumps were used as left and right ventricular assist devices. In the ischemic groups (ischemia only group and nitric oxide group), global ischemia was induced for 30 minutes and followed by a 6-hour reperfusion period; the nonischemic control group underwent a 6-hour perfusion period only. The left ventricular assist device was driven at a flow rate of more than 75 to 80 mL/(min. kg). The right ventricular assist device was driven so as to sustain the left ventricular assist device flow, and the animal was weaned from it in accordance with the objective of cardiac recovery. RESULTS: Mean pulmonary arterial pressure remained low in the nitric oxide group (mean 23 mm Hg), whereas it rose from 19.9 mm Hg to 39.3 mm Hg in the ischemia group and to 26.2 mm Hg in the control group. Mixed venous saturation was maintained at more than 60% in all cases. Although no piglets in the ischemia group were able to survive without continuous-flow biventricular assist support, the right ventricular assist device flow ratio (device flow/total systemic flow) in the nitric oxide group could be reduced in all cases, and it was possible to wean the piglets from right ventricular assist device support in 4 of 5 cases. CONCLUSION: Inhalation of 40-ppm nitric oxide enabled smoother maintenance of the left ventricular assist device flow and prompted the weaning from right ventricular assist device support on continuous-flow biventricular assist.

Administration, Inhalation↗

PubMedDate not supplied

A safe automatic driving method for a continuous flow ventricular assist device based on motor current pulsatility: in vitro evaluation.

We previously reported that detection of two specific points (the t-point and the s-point) in the relationship between pump speed and Motor Current Amplitude index (ICA) indicates the safe driving range for a continuous-flow ventricular assist device (CFVAD). During the first stage of the present experiment, the characteristic curves relating pump speed and ICA were determined by varying preload (left atrial pressure: -6 to 30 mm Hg), afterload (total circuit resistance: 890 to 3,180 dyne x sec x cm(-5)), and contractility of the left ventricle (total circuit flow: 0.5 to 2.1 L/min). These data showed that an ICA value of 0.18 was always located between the t- and s-points. During the second stage of the experiment, we developed an automatic driving program to control pump speed by maintaining ICA at 0.18. This program was able to drive the CFVAD, without exhibiting regurgitant flow or sucking, under various driving conditions in the mock circulation. Pump speed stabilized within 1 minute after varying the drive conditions. This sensorless method of driving the CFVAD by using a target ICA proved feasible and effective for safe automatic control, within our mock circulation.

Algorithms↗