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Biomedical subjects

T Shimono

Publications and source records attributed to T Shimono.

At least 37 records · Page 2Linked to original sources
PubMed2000

Long-term follow-up after Carpentier-Edwards ring annuloplasty for tricuspid regurgitation.

BACKGROUND: Use of flexible rings for tricuspid ring annuloplasty is becoming popular. This study was undertaken to evaluate Carpentier-Edwards (C-E) rigid ring annuloplasty for tricuspid regurgitation (TR), secondary to mitral valve disease and clinical outcome on a long-term basis. METHODS: From December 1985 to March 1996, 45 patients with secondary TR underwent C-E ring annuloplasty. Thirty-nine patients (95.1%) were in New York Heart Association (NYHA) functional class III or IV. The mean follow-up was 96.7+/-48.5 months or 362.6 patient-years. RESULTS: There were three in-hospital and nine late deaths that were not related to tricuspid annuloplasty. Actuarial survival at 10 years was 68.3%. Echocardiographic studies showed that TR was well controlled within grade 2+ in all survivors. Residual pulmonary hypertension (PH) was recognized in 9 of 21 patients (42.9%) with preoperative PH, however, no TR was seen in 6 patients. A TR grade of 2+ was observed in 3 patients. Thirty of the total survivors (96.8%) were in NYHA class I and II, but 1 patient was in NYHA class III. The actuarial rate of freedom from tricuspid valve reoperation after 10 years was 97.5%. CONCLUSIONS: C-E ring annuloplasty is acceptable for repair of secondary TR and improvement in clinical status on a long-term basis.

Adult↗
PubMed2000

Surgical repair of extracardiac unruptured acquired Valsalva aneurysms.

Two cases of extracardiac unruptured Valsalva aneurysms due to rare causes are reported. One patient had been suffering from hyper eosinophilic syndrome. Operative corrections consisted of total replacement of the aortic root. The other patient had an aneurysm of just noncoronary sinus of Valsalva and a dilated ascending aorta due to cystic mucoid degeneration. Replacement of the ascending aorta with patch closure for the aneurysm was successfully performed.

Aortic Aneurysm↗
PubMed2000

Biocompatibility of silicone-coated oxygenator in cardiopulmonary bypass.

BACKGROUND: This study was designed to analyze the biocompatibility of silicone-coated oxygenators using inflammatory response as the outcome measure, and to investigate whether the silicone-coated oxygenators perform better in terms of postoperative organ dysfunction. METHODS: The 32 patients who underwent cardiopulmonary bypass (CPB) were divided into 3 groups: group A (n = 10), heparin-coated circuit with silicone-coated oxygenator; group B (n = 11), whole heparin-coated circuit; and group C (n = 11), whole untreated circuit. The plasma concentrations of the proinflammatory markers, made of inflammatory cytokines (tumor necrosis factor-alpha, interleukin-1beta, interleukin-6, interleukin-8), terminal complement complex (C5b-9), and polymorphonuclear elastase (PMN-E), were measured by enzyme-linked immunosorbant assay. RESULTS: All proinflammatory markers were significantly lower in groups A and B than in group C, especially C5b-9 and PMN-E concentrations, which were significantly lower in group A than in group B. The alveolar-arterial oxygen gradients (A-aDO2) and the respiratory index were significantly better in group A than in group C. In group B, however, only the A-aDO2 was significantly better than in group C. The duration of intubation and the length of stay in the intensive care unit stay were significantly shorter in groups A and B than in group C. CONCLUSIONS: Silicone-coated oxygenators are biocompatible and prevent postoperative organ dysfunction.

Anticoagulants↗
PubMed2000

Five-year follow-up of valve replacement with the Jyros bileaflet mechanical valve.

Jyros bileaflet rotating valves were implanted as a clinical trial conducted in Japan, and the 5-year results were assessed. Nineteen patients underwent implantation of the valves: 14 in the mitral and 5 in the aortic position. The mean follow-up period was 65.4+/-15.7 months. There was 1 case of late death due to fatal arrhythmia and another case of cerebral thromboembolism (1.0% per patient year). All survivors were in New York Heart Association class I. On the early postoperative cinefluorography, 8 valves (42.1%) showed rotation of the leaflets. However, in the latest assessment 6 valves (33.3%) showed rotation, some valves had stopped rotation, and others had started to rotate during the follow-up period. The Jyros valve functions effectively, similar to other bileaflet valves. However, because the correlation between thromboembolism and the rotation mechanism is not clear, further follow-up of our patients and more implant studies are necessary to elucidate this issue.

Adult↗
PubMed2000

[The effects of intravenous milrinone for the patient undergoing CABG].

The hemodynamic effects of intravenous infusion of milrinone were evaluated in 25 patients undergoing CABG using an internal mammary artery graft. Milrinone was administered to 9 patients at the time of weaning from cardiopulmonary bypass, at a dosage of 3 to 5 micrograms/kg/min. Postoperative cardiac function was compared in this group versus the other 17 patients who were treated without milrinone. We determined such parameters as cardiac index, wedge pressure and mean pulmonary pressure. Our findings did not show any significant difference between the 2 groups. We also studied a subject of low-output patients (EF < 0.5). In the patients with low-cardiac output, the use of milrinone in addition to standard postoperative administration of low-dose dopamine reduced mean pulmonary pressure and wedge pressure. Thus, milrinone not only improved the left ventricular function, but also expanded the pulmonary vascular bed.

Aged↗
PubMed2000

Atopic dermatitis as a risk factor for acute native valve endocarditis.

Colonization of Staphylococcus aureus is commonly observed in skin lesions of atopic dermatitis (AD) patients, and scratching of the pruritic lesions may lead to reiterative bacteremia. It is possible that acute native valve endocarditis may develop in a patient with uncontrolled AD; the latter condition may be a risk factor for the former. We report two cases of acute aortic and/or mitral valve endocarditis complicated with recurrent cutaneous infections caused by severe AD. The patients underwent successful surgical treatment of the heart lesions, plus intensive postoperative antibiotics and skin treatment for AD.

Adolescent↗
PubMed2000

The role of cyclosporine A and interleukin-2 in obliterative airway disease in a rat tracheal transplant model.

The pathogenesis of obliterative bronchiolitis (OB) following lung and heart-lung transplantation remains unclear. We evaluated the role of CsA and IL-2 on the development of obliterative airway disease (OAD) by administrating exogenous IL-2 in a CsA-treated rat tracheal transplant model. Tracheal grafts were implanted into the peritoneal cavity from Brown Norway (BN) to BN rats or to Lewis (LEW) rats. Allotransplant: No treatment was given in group 1. Short-term CsA (25 mg/kg, i.m. on POD 2 and 3) was used in group 2. Group 3 was treated with long-term CsA (25 mg/kg, i.m. on POD 2 and 3, followed by 5 mg/kg on POD 4 to 27). Administration of IL-2 (300, 000 IU/kg, i.p. on POD 15 to 19 and 22 to 26) was performed to long-term CsA treated rats in group 4. Isotransplant: No treatment was given to group 5, group 6 was treated with IL-2 (same regimen as in group 4). Grafts were harvested at different time points after Tx for histological assessment. No luminal obliteration was observed in group 5 and 6. Complete luminal obliteration was noted 4 weeks after Tx in group 1. In group 2 and 3, obliterative lesion occurred 4-6 weeks after CsA withdrawal. IL-2 increased epithelial loss, lymphocytic infiltration, and obliterative changes in group 4. Our results suggest that OAD is an immune mediated disorder. Furthermore, administration of exogenous IL-2 might be able to abrogate the protection from OAD by CsA therapy.

Animals↗
PubMed2000

[The perioperative management for the patients to undergo open heart surgery with chronic renal failure].

From January, 1996 to December, 1999, eight patients with chronic renal failure received open heart surgery. They consists of six males and two females aged between 45 and 72 with a mean of 59.6. The duration of hemodialysis was 4.0 years in a mean. Seven of them had isolated coronary artery bypass grafting (CABG), one of them had CABG and aortic valve replacement. All patients were dialysed dialy two days before operation. Intraoperative hemodialysis (HD) was used in all patients. In recent six patients extracorporeal ultrafiltration methods (ECUM) were also performed intraoperatively in addition to HD. In postoperatively continuous hemodiafiltration (CHDF) has been preferred to HD in all patients, and nafamostat mesilate is a useful anticoagulation agent to prevent postoperative bleeding complications. The duration of CHDF was 3.2 days in a mean (the shortest for one day and the longest for eight days). When the circulatory situation were stable, HD was performed on early postoperative day. One patients died of low output syndrome and multiple organ failure. We reported problems in perioperative management of patients with chronic renal failure and our protocol.

Aged↗
PubMed1999

Endovascular stent-graft placement for the treatment of acute aortic dissection.

BACKGROUND: The standard treatment for acute aortic dissection is either surgical or medical therapy, depending on the morphologic features of the lesion and any associated complications. Irrespective of the form of treatment, the associated mortality and morbidity are considerable. METHODS: We studied the placement of endovascular stent-grafts across the primary entry tear for the management of acute aortic dissection originating in the descending thoracic aorta. We evaluated the feasibility, safety, and effectiveness of transluminal stent-graft placement over the entry tear in 4 patients with acute type A aortic dissections (which involve the ascending aorta) and 15 patients with acute type B aortic dissections (which are confined to the descending aorta). Dissections involved aortic branches in 14 of the 19 patients (74 percent), and symptomatic compromise of multiple branch vessels was observed in 7 patients (37 percent). The stent-grafts were made of self-expanding stainless-steel covered with woven polyester or polytetrafluoroethylene material. RESULTS: Placement of endovascular stent-grafts across the primary entry tears was technically successful in all 19 patients. Complete thrombosis of the thoracic aortic false lumen was achieved in 15 patients (79 percent), and partial thrombosis was achieved in 4 (21 percent). Revascularization of ischemic branch vessels, with subsequent relief of corresponding symptoms, occurred in 76 percent of the obstructed branches. Three of the 19 patients died within 30 days, for an early mortality rate of 16 percent (95 percent confidence interval, 0 to 32 percent). There were no deaths and no instances of aneurysm or aortic rupture during the subsequent average follow-up period of 13 months. CONCLUSIONS: These initial results suggest that stent-graft coverage of the primary entry tear may be a promising new treatment for selected patients with acute aortic dissection. This technique requires further evaluation, however, to assess its therapeutic potential fully.

Acute Disease↗
PubMed1999

Lymphocytic hypophysitis presenting with diabetes insipidus: MR findings.

It has been thought that neurohypophysial involvement manifesting as central diabetes insipidus in lymphocytic hypophysitis is rare. The radiological and clinicopathological features of two cases represent a variant of lymphocytic adenohypophysitis and/or lymphocytic infundibulo-neurohypophysitis are discussed.

Diabetes Insipidus↗
PubMed1999

Afferent and efferent nerve activity of arterial baroreceptor reflex under nonpulsatile systemic circulation.

We studied the changes in arterial baroreceptor reflex (ABR) afferent activity and efferent activity induced by nonpulsatile systemic circulation (NC) during total left heart bypass (TLHB) in rabbits. To evaluate the influence of the circuit priming fluid and exposure to NC, we directly measured aortic depressor nerve activity (ADNA) (n = 5) and renal sympathetic nerve activity (RSNA) (n = 5) before the start of partial left heart bypass (PLHB) (Before), after PHLB (After), and 5 min after the start of TLHB (During THLB) while maintaining the mean aortic pressure. The circuit priming fluid did not affect the ABR. ADNA exhibited periodic discharge at Before and After, but at During THLB, this periodic discharge transformed into a continuous discharge, and ADNA increased significantly. However, there were no significant differences in RSNA. Our results suggested that in the acute phase under NC, the ABR differed from that under natural circulation.

Adrenergic Agonists↗
PubMed1999

Rapid progression of pituitary hyperplasia in humans with primary hypothyroidism: demonstration with MR imaging.

PURPOSE: To use magnetic resonance (MR) imaging to evaluate the morphologic changes of the pituitary gland during the development of hypothyroidism. MATERIALS AND METHODS: Fourteen patients who had undergone thyroidectomy were evaluated before radioactive iodine 131 therapy. In each patient, MR imaging and measurement of serum hormone levels were performed twice: 5 weeks before 131I treatment as the "euthyroid state" with thyroid hormone supplementation and on the day of 131I treatment as the "hypothyroid state" after a 3-week depletion of thyroid hormone supplements. Nine healthy volunteers also underwent MR imaging twice at an interval of 5 weeks. Pituitary volume and the relative signal intensity ratio of the anterior pituitary to the pons were measured. The shape and signal intensity of the pituitary gland were also visually assessed. The paired Student t test was used to evaluate the significance of the data. A P value less than .05 indicated a statistically significant difference. RESULTS: The patients had significantly larger pituitary volume in the hypothyroid state than in the euthyroid state both quantitatively (P < .001) and visually. No significant differences were found in the relative signal intensity ratios of the anterior pituitary to the pons. In healthy volunteers, no significant differences in pituitary volumes or signal intensity were found between the two MR images. CONCLUSION: Rapid progression of hyperplasia of the anterior pituitary may occur with acute development of hypothyroidism.

Adult↗
PubMed1999

[Completion pneumonectomy combined with graft replacement of thoracic aortic aneurysm by simple clamping].

A 59-years-old male patient who had left upper lobe partial resection 30 years ago. He was seen at the family physician because of cough. A chest X-ray was showing an abnormal mass shadow measuring 3 x 4 cm in left lower lobe like honey comb. And squamous cell carcinoma (SCC) was detected in his sputum. He was diagnosed as primary lung cancer and introduced to our department to have operation. Chest CT-scan was showing lung tumor suspected SCC measuring 4.3 x 2.6 cm in segment 8 faced chest wall. At the same time, we detected thoracic aortic aneurysm and subcarinal lymph node, but could not see where the boundary is, so it was hard to distinguish between parietal thrombus with thoracic aortic aneurysm and swelling subcarinal lymph node. We decided it swelling subcarinal lymph node by three-dimensional treated CT-scan. Aortic angiography was showing proximal descending aortic aneurysm measuring diameter was 4.5 cm. Abdominal CT-scan was showing infrarenal abdominal aortic aneurysm measuring diameter was 5.5 cm. He was diagnosed as primary lung cancer (It. S8, SCC) (cT2N2M0, Stage IIIB), thoracic aortic aneurysm, abdominal aortic aneurysm, and idiopathic pulmonary fibrosis, and had completion pneumonectomy (R 2 b) for primary lung cancer and graft replacement with aneurysm dissection for thoracic aortic aneurysm without extracorporeal circulation. In this operation, we could find swelling subcarinal lymph node measuring 5 x 3 cm instead of parietal thrombus with thoracic aortic aneurysm. Pathological examination diagnosed middle differential SCC and no metastasis from dissected lymph node (PT2N0M0, Stage I A).

Aorta, Thoracic↗
PubMed1999

[Early and mid-term results of endovascular stent grafting for aortic aneurysms].

Early and mid-term clinical results of 28 cases of endovascular stent grafting for descending thoracic aortic aneurysms and 11 cases of abdominal aortic aneurysms are reported. Early clinical results: Among 28 patients (7 true thoracic aortic aneurysms, 3 pseudothoracic aortic aneurysms and 8 acute, 4 subacute, and 6 chronic aortic dissections), two patients (7.1%) with ruptured acute aortic dissection or ruptured infected pseudoaneurysm died in the perioperative period. Two of the remaining 26 patients experienced minor complications. Aneurysmal sacs or false lumens at the descending thoracic aorta were completely thrombosed in the 26 patients. One patient (9.1%) with a ruptured abdominal aneurysm died, and one of the remaining 10 patients had renal and peripheral emboli and peripheral vascular trauma. Inadvertent covering of the renal arteries occurred in another patient. Unless one patient had persistent endoleak, aneurysmal sacs in the 10 surviving patients were thrombosed. Mid-term clinical results: One aortic dissection at a different section of the descending aorta occurred 6 months after stent grafting for aortic dissection, and one patient died of pneumonia 3 months after stent grafting for an abdominal aortic aneurysm. CT scanning 6 months after stent grafting revealed a decrease in maximal aneurysmal size in 3 of 9 patients with true or pseudothoracic aneurysms and in 2 of 5 patients with abdominal aortic aneurysms. Five of 9 patients with stent grafting for acute or subacute dissection showed elimination of the false lumen in the descending thoracic aorta in a CT scan 6 months after grafting. One patient with a true thoracic aneurysm and one patient with an abdominal aortic aneurysm showed an increase in aneurysmal size in a CT scan 2 years and one year after treatment, respectively.

Aged↗
PubMed1998

Terminal warm blood cardioplegia improves cardiac function through microtubule repolymerization.

BACKGROUND: To elucidate the mechanisms responsible for the beneficial effects of terminal warm blood cardioplegia, we studied dynamic change in microtubules induced by cold cardioplegia followed by rewarming. Further, we investigated the relationship between cardiac function and morphologic changes in microtubules caused by hyperkalemic, hypocalcemic warm cardioplegia during initial reperfusion. METHODS: In protocol 1 isolated rat hearts were perfused at 37 degrees C with Krebs-Henseleit buffer (KHB). After 3 hours of hypothermic cardiac arrest at 10 degrees C, hearts were reperfused at 37 degrees C with one of two buffers: group C, 60-minute reperfusion with KHB (K+, 5.9 mmol/L; Ca2+, 2.5 mmol/L); and group TC, 10-minute initial reperfusion with modified KHB (K+, 15 mmol/L; Ca2+, 0.25 mmol/L), followed by 50 minutes of reperfusion with KHB. Cardiac function after reperfusion was determined as a percentage of the prearrest value. In protocol 2 hearts were perfused at 37 degrees C with KHB containing colchicine (10(-5) mol/L) for 60 minutes. RESULTS: There was spontaneous contractile recovery after 10 minutes of initial reperfusion in hearts from group TC as well as improved cardiac function after 15, 30, and 60 minutes of reperfusion compared with that in group C. Immunohistochemical staining and immunoblot analysis demonstrated microtubule depolymerization during hypothermic cardiac arrest and complete repolymerization after 10 minutes of reperfusion with warm buffers in both groups. Colchicine-induced microtubule depolymerization is associated with deterioration of cardiac function. CONCLUSIONS: One mechanism responsible for improved cardiac function mediated by terminal warm blood cardioplegia is the restart of contraction after complete microtubule repolymerization.

Animals↗