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J Nishizawa

Publications and source records attributed to J Nishizawa.

At least 19 recordsLinked to original sources
PubMed2001

Coronary artery bypass grafting for patients with an atherosclerotic ascending aorta.

OBJECTIVES: We review the outcome of coronary artery bypass grafting in patients with a severe atherosclerotic ascending aorta. METHODS: Subjects were 31 patients averaging 69.4 +/- 6.9 years old studied from 1990 through 1998. Ascending aortic lesions were assessed using epiaortic echo and 2 types of aortic nonclamping techniques applied. In 29 patients operated on in the early years, bypass grafting was conducted on the hypothermic fibrillated heart in 22 and on the beating heart in 7. The remaining 2 underwent off-pump coronary artery bypass grafting more recently. For cases with multivessel disease, we used composite grafting. RESULTS: Three patients developed mild stroke and 5 died within 30 days of surgery--4 from multiple emboli (1 accompanied by a stroke) and 1 from perioperative myocardial infarction. One hospital death occurred due to brain damage and multiorgan failure following unexpected rupture of a saphenous vein graft. No cardiac deaths occurred in the late stage of our series. Actuarial survival was 73.0% for 3 years and 68.0% for 5 years. Freedom from cardiac events was favorable in the remaining 25 survivors. CONCLUSIONS: Outcome was suboptimal for the risks involved. Recent technical advances, including coronary surgery on the beating heart with or without cardiopulmonary bypass using variable in-situ or free arterial grafts, associated with adequate evaluation of systemic atherosclerosis, should improve this outcome.

Aged↗
PubMed2001

Telomerase activation and p53 mutations in urethane-induced A/J mouse lung tumor development.

The mouse telomerase holoenzyme, which synthesizes telomeric DNA de novo, is a ribonucleoprotein complex that includes the mouse telomerase RNA component (mTERC), mouse telomerase-associated protein (mTEP1) and mouse telomerase reverse transcriptase (mTERT). To determine the role of telomerase in urethane-induced lung tumorigenesis in A/J mice we examined telomerase activity and the expression of each telomerase subunit in 20 tumor samples, harvested at 16, 28, 40 and 50 weeks after urethane treatment. The telomeric repeat amplification protocol assay showed that statistically significant telomerase activation occurred both early and late in tumorigenesis. Semi-quantitative reverse transcription-polymerase chain reaction analysis revealed that mRNA expression levels of mTEP1 and mTERT were up-regulated during tumor progression, while mTERC expression was not significantly different between tumors and normal lung. We further examined mTEP1 protein expression in normal lung tissue and lung tumors; western blot analysis showed preferential expression of mTEP1 protein in lung tumors compared with normal lung and immunohistochemistry revealed that a majority of the adenoma cells were positively stained in the nucleus, whereas only a few of the adjacent normal alveolar cells were immunoreactive. In addition, we investigated DNAs of the 20 tumor samples by single strand conformation polymorphism and sequencing analyses to examine whether alterations of the p53 gene in exons 5-8 were associated with telomerase activity. Although we found one nonsense, two missense, two silent and one simultaneous double mutation at different codons in six late stage tumors, there was no apparent correlation between telomerase activity and p53 mutations. Collectively, these results suggest that mTEP1 as well as mTERT may be involved in the regulation of telomerase activity and that telomerase activation may contribute to lung tumorigenesis in A/J mice independently of p53 gene alterations.

Animals↗
PubMed2001

Clinical characteristics of patients with constrictive pericarditis after coronary bypass surgery.

Constrictive pericarditis (CP) is an unusual sequela of cardiac surgery, so the present study evaluated the clinical characteristics of patients with CP after coronary artery bypass grafting (CABG). Four hundred and sixty-three patients who underwent isolated CABG between January 1989 and March 1999 were examined retrospectively. The first choice of treatment for postoperative pericardial effusion was non-steroid anti-inflammatory agents, and an increased dose of diuretics. The second treatment choice was corticosteroids or pericardial drainage. When CP was suspected during the follow-up period (mean, 54+/-31 months), cardiac catheterization was carried out to establish the diagnosis. Of the 463 patients undergoing CABG, there were 11 (2.4%) who developed CP after surgery. The median time to the onset of symptoms after CABG was 4 weeks (range, 3-96 weeks). On univariate and multivariate analysis, normal left ventricular ejection fraction, warfarin administration, and early postoperative pericardial effusion were significantly associated with a greater potential of postoperative CP. The effusion was bloody in all cases of pericardial drainage despite warfarin therapy. Not draining the postoperative effusive pericardial effusion was a risk factor for the development of CP. Pericardial drainage for patients with significant effusion after CABG is important for the prevention of subsequent CP, especially in those patients being treated with warfarin or with normal left ventricular function.

Aged↗
PubMed2001

Aortic laceration due to prolapse of the bicuspid aortic valve: case report.

Reports of aortic regurgitation due to rupture of the aortic valve commissures are rare. Prompt surgical intervention is necessary, as the condition results in rapid, progressive heart failure and subsequent death. We report the case of a 78-year-old man who presented with aortic laceration and cardiac tamponade that was probably induced by prolapse of the bicuspid aortic valve. We speculate that prompt initial surgery may have prevented aortic laceration and cardiac tamponade in this patient. Thus, in order to optimize clinical outcome, clinicians must consider early, precautionary surgical management in patients who have sudden cardiac failure due to aortic regurgitation associated with prolapse of the bicuspid aortic valve.

Aged↗
PubMed2000

[Long-term effect of polystan monocusp ventricular outflow patch after right ventricular outflow tract reconstruction].

Forty-eight patients who underwent right ventricular outflow tract reconstruction with Monocusp Ventricular Outflow Patch (MVOP) fifty-five times and survived surgery, were reviewed in this study. Mean age at surgery was 6.4 years-old and mean follow-up interval was 75.2 months. There was no late death, however reoperation was performed 7 times. Freedom from reoperation rate was 97.2% and 80.7% after 5 and 10 years after surgery, respectively. The main cause for reoperation were right ventricular outflow obstruction RVOTO (5 cases). All of the RVOTO occurred at the distal end of the anastomosis. However, there was no RVOTO in patients who underwent RVOTR with MVOP during the past ten years. So, we considered the cause of RVOTO a technical problem. Pulmonary regurgitation was one to two degree early after surgery, and had worsened by almost two or three degrees more than 5 years after surgery. Moreover, five of six patients who underwent cardiac catheterization more than 10 years after surgery had three degrees of pulmonary regurgitation as well as a large CTR. In conclusion, according to long-term results, especially more than 10 years post operatively, pulmonary regurgitation was the most important problem.

Adolescent↗
PubMed2000

[A surgical case of acute massive pulmonary embolism associated with a giant free-floating inferior vena cava thrombus].

The risk and mortality of pulmonary embolism is high in patients with free-floating inferior vena cava thrombi. We present a successful surgical case of a 70-year-old male who had acute massive pulmonary embolism associated with a giant free-floating inferior vena cava thrombus extending above the renal veins. Emergent thrombectomy of the pulmonary artery and the inferior vena cava using cardiopulmonary bypass was carried out because he was considered at high risk for fatal recurrent pulmonary embolism. Prophylactical insertion of a Greenfield filter in the inferior vena cava was added. In this report, diagnosis and treatment of inferior vena cava thrombosis is also discussed.

Acute Disease↗
PubMed1999

Reactive oxygen species play an important role in the activation of heat shock factor 1 in ischemic-reperfused heart.

BACKGROUND: The myocardial protective role of heat shock protein (HSP) has been demonstrated. Recently, we reported that ischemia/reperfusion induced a significant activation of heat shock factor (HSF) 1 and an accumulation of mRNA for HSP70 and HSP90. We examined the role of reactive oxygen species (ROSs) in the induction of stress response in the ischemic-reperfused heart. METHODS AND RESULTS: Rat hearts were isolated and perfused with Krebs-Henseleit buffer by the Langendorff method. Whole-cell extracts were prepared for gel mobility shift assay using oligonucleotides containing the heat shock element. Induction of mRNA for HSP70 and HSP90 was examined by Northern blot analysis. Repetitive ischemia/reperfusion, which causes recurrent bursts of free radical generation, resulted in burst activation of HSF1, and this burst activation was significantly reduced with either allopurinol 1 mmol/L (an inhibitor of xanthine oxidase) or catalase 2x10(5) U/L (a scavenger of H2O2). Significant activation of HSF1 was observed on perfusion with buffer containing H2O2 150 micromol/L or xanthine 1 mmol/L plus xanthine oxidase 5 U/L. The accumulation of mRNA for HSP70 or HSP90 after repetitive ischemia/reperfusion was reduced with either allopurinol or catalase. CONCLUSIONS: Our findings demonstrate that ROSs play an important role in the activation of HSF1 and the accumulation of mRNA for HSP70 and HSP90 in the ischemic-reperfused heart.

Allopurinol↗
PubMed1999

Combined cardiac surgery and total thyroidectomy: a case report.

A 65-year-old woman with aortic stenosis, ischemic heart disease, and Graves' disease had complained of effort angina. She then suffered from liver dysfunction due to treatment with antithyroid drugs. One year after the start of radioiodine administration, she demonstrated unstable angina with palpitation and sweating. Laboratory studies revealed a recurrent hyperthyroid state, and a second coronary angiogram revealed progressive ischemic heart disease. Combined coronary artery bypass grafting, aortic valve replacement, and total thyroidectomy were performed. The postoperative course was uneventful without any problems associated with hyperthyroidism or hypothyroidism. Combined cardiac surgery and total thyroidectomy can be performed safely if the perioperative levels of thyroid hormone are maintained at euthyroid or hypothyroid levels.

Aged↗
PubMed1996

Reperfusion causes significant activation of heat shock transcription factor 1 in ischemic rat heart.

BACKGROUND: The myocardial protective role of heat shock protein (HSP) has been demonstrated, and there has been increasing interest in stress response in the heart. We examined the DNA-binding activity of heat shock transcription factor (HSF), by which the transcription of heat shock genes is mainly regulated, during heat shock or ischemia/reperfusion in isolated rat heart. METHODS AND RESULTS: Rat hearts were isolated and perfused with Krebs-Henseleit buffer by the Langendorff method. Whole-cell extracts were prepared for gel mobility shift assay using oligonucleotides containing the heat shock element, which is present upstream of all heat shock genes. Induction of mRNAs for HSP70, HSP90, and GRP78 (glucose-regulated protein) was examined by Northern blot analysis. Although the activation of HSF during global ischemia was weak and rapidly attenuated, postischemic reperfusion induced a significant activation of HSF. In addition, although HSP70 mRNA was hardly induced during ischemia, its burst induction was detected during postischemic reperfusion. Supershift assays using specific antisera for HSF1 and HSF2 revealed that ischemia/reperfusion as well as heat shock induced the activation of HSF1 in hearts. Although the expression of HSP70 mRNA during heat shock was more vigorous than the expression during ischemia/reperfusion, the induction of HSP90 mRNA in postischemic reperfusion was significantly greater than that in heat shock. CONCLUSIONS: Our findings demonstrated that reperfusion causes a significant activation of HSF1 in ischemia-reperfused heart. The striking contrast between the induction of HSP70 mRNA and that of HSP90 mRNA suggests the presence of regulatory mechanisms other than HSF.

Animals↗
PubMed1995

[Surgical treatment of congenital aortic stenosis by aortoseptal approach].

Between 1975 and 1994, six patients under 15 years old with congenital aortic stenosis underwent relief of left ventricular outflow tract obstruction (LVOTO) by aortoseptal approach. Although we got satisfactory relief of LVOTO in all patients, there were two late deaths. In one patient with residual ventricular septal defect (VSD), intractable ventricular arrhythmia developed 12 years postoperatively. Although the residual VSD closure was performed, the patient died of the arrhythmia. The another one who was the youngest 4-year-old boy suddenly died 4 months postoperatively. The detail about his death was unknown, but we presumed ischemic heart attack as the cause of his death. In 3 of remaining survived 4 patients, we encountered a few complications. They were right ventricular outflow obstruction, coronary artery injury and conduction system injury. All complications and problems we encountered in this series were related to the incision and the reconstruction of aortoseptal approach. In conclusion, the aortoseptal approach is effective technique for relief of LVOTO, but on the other hand it is invasive and not so safe operation. So we should be cautious about these complications and problems.

Adolescent↗
PubMed1994

[Right ventricular function after aorto-coronary bypass surgery: with relation to the site of right coronary artery occlusion].

Postoperative right ventricular function was evaluated serially by thermodilution techniques (REF-1, Edwards Laboratories) in patients who underwent aorto-coronary bypass surgery with uneventful postoperative recovery. The patients were divided into three groups depending on the location of critical stenosis of the right coronary artery. The stenosis was proximal to the right ventricular branch in group I (n = 13), distal to the right ventricular branch but proximal to the acute marginal branch in group II (n = 13) and distal to the acute marginal branch in group III (n = 11). Control (n = 20) consisted of the patients with no significant stenosis of the right coronary artery. Cardiac index, intracardiac pressures and amount of cathecolamin used during postoperative course showed no significant differences among the groups including control. With the use of cathecolamine after surgery, right ventricular ejection fraction (RVEF) rose and right ventricular volumes (RVEDV and RVESV) decreased in all the groups except for group I. These values in group I were unchanged. Thus, there were significant differences in RVEF, RVEDV and RVESV between group I and control. These results mean that right ventricular dysfunction may remain even long after occlusion of the proximal right coronary artery.

Aged↗
PubMed1994

[Coronary artery bypass grafting in the patients with previous cerebral infarction: the risk of perioperative cerebral complications].

From Oct. 1987 to Apr. 1992, coronary artery bypass grafting (CABG) was performed in 33 patients who had a history of previous cerebral infarction. Two patients associated with severe carotid disease underwent combined carotid endarterectomy and CABG. There have been no perioperative cerebral complications. On the other hand, in 199 patients without a history of previous cerebral infarction, three patients (1.5%) suffered perioperative cerebral infarction. In two of these patients, the etiology was felt to be calcific and atherosclerotic debris from the ascending aorta and in the remaining patient, to be arterial hypotension during cardiopulmonary bypass. In conclusion, no direct relationship has been found between previous cerebral infarction and incidence of perioperative cerebral complications.

Aged↗
PubMed1993

[Emergency aorto-coronary bypass surgery for patients with right ventricular infarction].

Infarction of the right ventricle occurs with acute inferior myocardial infarction and results in a unique syndrome, characterized by distended neck vein, hypotension, heart block and spontaneous recovery in right ventricular function with time. We performed aorto-coronary surgery for four patients with right ventricular infarction. Three of them had emergency surgery. Surgical indications were refractory angina pectoris in two and cardiogenic shock in one. Postoperative courses in these patients were stormy and two died. Low output syndrome rarely improved with volume load alone and required inotropic and vasoactive drugs. Antiarrhythmic therapy including artificial pacing was especially important in keeping IABP support effectively. Remaining case, on the other hand, were conservatively supported by IABP and drug therapy through the first two weeks after infarction and then operation was done for unstable angina. Postoperative course in this patient was uneventful. In conclusion, delayed surgical intervention may be considered in patients with right ventricular infarction if their hemodynamic condition in the early stage of infarction can be conservatively managed.

Aged↗
PubMed1993

[Combined carotid endarterectomy and coronary artery bypass grafting: a report of two cases].

We reported two cases of successful combined carotid endarterectomy and coronary artery bypass grafting. The first case was a 60-year-old male who had unstable angina pectoris and a history of two times of cerebral infarction. He was revealed to have severe stenosis of left internal carotid artery as well as diffuse stenosis of right and left coronary arteries. The second case, 67-year-old male with a history of cerebral infarction, was admitted because of anterior myocardial infarction. Coronary angiography revealed left main trunk disease and carotid angiography also revealed critical stenosis of bilateral internal carotid arteries. We discussed the management of the patients having coexistent such coronary and carotid artery disease.

Aged↗
PubMed1993

[Acute aortic dissection without opacification of the false lumen on the initial aortogram: a case report].

A 50-year-old woman was admitted to the intensive care unit 40 min after the onset of severe chest and back pain with consciousness loss. Emergency computed tomography and aortography demonstrated an acute type A dissection without opacification of the false lumen. The patient was initially treated with antihypertensive drugs. Recurrent back pain and bilateral pleural effusion appeared 3 days after onset of the pain. Both the right radial and carotid pulses were reduced. Emergent operation was performed when computed tomography and aortography repeated 5 days after onset of the pain demonstrated the intimal flap in the ascending aorta with the opacified false lumen. The site of intimal tear in the proximal arch was resected and a 26 mm Dacron graft was inserted during deep hypothermia and circulatory arrest. The postoperative course was uneventful.

Aortic Dissection↗