Search PubMed⌕ Search

Biomedical subjects

J Amano

Publications and source records attributed to J Amano.

At least 163 records · Page 9Linked to original sources
PubMed1994

[Reoperation for valvular heart disease: its operative procedure and result].

From April, 1983 to March, 1993, 63 patients (pts) underwent reoperations of valvular heart disease at Tokyo Medical and Dental University Hospital, of which 44 pts had undergone closed mitral commissurotomy (CMC), open aortic or mitral commissurotomy (OAC or OMC) or valvuloplasty, and 17 pts had undergone aortic or mitral valve replacement (AVR or MVR). Valve replacement was performed in 59 pts (mechanical valve replacement; 42 pts, porcine valve replacement; 12 pts), and 2 pts received OMC due to restenosis after CMC. Preoperative diagnosis included restenosis after CMC, OMC or valvuloplasty in 43 pts, bioprosthetic dysfunction after MVR in 10 pts, perivalvular leakage after AVR in 1 pt, valve detachment after AVR in 4 pts (Beçhet 3 pts, infective endocarditis 1 pts). Valve replacement or valvuloplasty was done for another valves in addition to the previously operated valve in 44 pts (72.1%), especially for tricuspid valve. Restenosis after CMC, occurred at 20.6 years after surgery, and restenosis after OMC and valvuloplasty at 13.1 years. Bioprosthetic dysfunction after MVR occurred at 8.5 years. Valve dysfunction of the mechanical valve was not observed. The early operative mortality after reoperations was 11.5% (7 pts) in this series. And 3 pts (4.9%) died in the late follow-up due to cancer in 1 pt and congestive heart failure in 2 pts. A first choice of mechanical valve for redo valve replacement for aortic/mitral valve, and modified AVR using composite graft and proximal double fixation to the fragile annulus seemed to be satisfactory to accomplish better operative results.

Adolescent↗
PubMed1993

O-linked neutral sugar chains of porcine zona pellucida glycoproteins.

The O-linked sugar chains were liberated from porcine zona pellucida glycoproteins by alkaline-borohydride treatment and the structures of neutral oligosaccharides were determined. The major oligosaccharides had the following structures with type-1 cores, (Gal beta 1-->4GlcNAc beta 1-->3)1 3-Gal bdta 1-->3N-acetylgalactosaminitol (54%) and GlcNAc beta 1-->3(Gal beta 1-->4GlcNAc beta 1-->3)0-1Gal beta 1-->3N- acetylgalactosaminitol (16%). Approximately 6% of the oligosaccharides had the structure with a type-3 core, Gal beta 1-->4GlcNAc beta 1-->3N-acetylgalactosaminitol. Oligosaccharides having alpha-galactose (2%) and beta-GalNAc (4%) at their non-reducing termini were also found as minor components.

Animals↗
PubMed1993

Atrial natriuretic peptide in the pericardial fluid of patients with heart disease.

1. The pericardial fluid of 20 open heart surgery patients with acquired heart disease was analysed for atrial natriuretic peptide by radioimmunoassay. 2. The concentration of atrial natriuretic peptide in the pericardial fluid was significantly higher than in the corresponding plasma (316.8 +/- 50.0 versus 121.7 +/- 29.1 pg/ml; P < 0.01) and was higher in patients with congestive heart failure than in those without heart failure (469.3 +/- 78.6 versus 181.8 +/- 26.7 pg/ml; P < 0.001). Pericardial and plasma atrial natriuretic peptide concentrations showed a significant positive correlation. Pericardial fluid and plasma samples were fractionated using both reverse-phase high-performance liquid chromatography and gel permeation chromatography. Each fraction was assayed for atrial natriuretic peptide by radioimmunoassay, revealing the presence of beta-atrial natriuretic peptide as well as alpha- and gamma-atrial natriuretic peptide. 3. The pericardial fluid concentration of cyclic GMP, the intracellular second messenger for atrial natriuretic peptide, was significantly higher in patients with congestive heart failure than in patients without heart failure.

Adult↗
PubMed1993

Antidiuretic hormone and cardiovascular responses during and after coronary artery bypass surgery.

In order to evaluate correlations in changes of postoperative plasma antidiuretic hormone (ADH) concentrations and hemodynamic parameters, 23 patients undergoing coronary artery bypass surgery were observed. 6 patients required intraaortic balloon pumping (IABP) (group I), 8 patients did not require IABP or inotropic agent (group II), and 9 patients required inotropic agent (group III) for weaning from cardiopulmonary bypass (CPB). Soon after CPB mean arterial and pulse pressures were significantly less in group I compared to other groups. Plasma ADH concentrations were significantly higher in group I than in group II, and showed significant negative correlation with hemodynamic parameters. On the 2nd postoperative day, plasma ADH concentrations in group I were significantly higher than in the other two groups, but were not correlated with hemodynamic parameters. Thus, early after surgery high plasma ADH concentrations in the IABP group directly reflected hemodynamic derangement, while at later times ADH secretion was influenced mainly by postsurgical stress.

Adult↗
PubMed1993

[Omental implantation technique for esophageal perforations--a clinical case and experimental studies].

We successfully used the omental implantation technique in a case of esophageal perforation in which simple closure was impossible because of extreme inflammatory changes. Although excellent results have been obtained by this method in gastroduodenal perforations, it has never been used before in cases of esophageal perforations. In this study we subsequently investigated the histological repair mechanism by carrying out animal experiments. Clinical case A 59-year-old male entered our hospital with the symptoms of chest pain and fever after endoscopic therapy for esophageal obstruction by food impaction. He underwent an emergency thoracotomy 54 hours after endoscopy. A perforation of about 2 cm in diameter was observed in the subthoracic esophageal wall which become too weak to close by stitching. This perforation was filled with an omental plug inserted from the peritoneal cavity under laparotomy. The patient recovered and his perforated lesion was completely repaired. Animal experiment In 10 hybrid adult dogs, omental implantation was performed on perforations of more than 1 cm in diameter in the subthoracic esophagus made by electric coagulation. One to four weeks postoperatively, these inserted omentums were observed endoscopically before sacrifice. The implanted omentums were endoscopically observed as elevated lesions after 2 weeks, but they became flat after 3 weeks and the mucosa seemed to be almost normal after 4 weeks. Histological investigation showed that the implanted omentums maintained their original structure accompanied by remarkable inflammatory changes 1 week postoperatively.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1993

Mechanism of changes of the collagen matrix of reperfused myocardium in donor heart preservation.

Isolated canine hearts were preserved for 6 hours at 5 degrees C followed by normothermic reperfusion for 2 hours. Dogs were divided into two groups: group I (group Ia [n = 7] and group Ib [n = 3] with the left ventricle unloaded during reperfusion) received a preservation solution containing potassium (20 mmol/L), and group II (n = 9) received University of Wisconsin solution. Left ventricular diastolic function was better preserved in group II. Degradation and loss of the collagen network during reperfusion, as assessed by scanning electron microscopy, were more extensive and significantly more frequent in group Ia than in group II (6/7 versus 2/9; p < 0.05). Furthermore, extensive disruption of the collagen network was significantly more prevalent in hearts with a left ventricular end-diastolic pressure of more than 20 mm Hg than in hearts with a left ventricular end-diastolic pressure of less than 20 mm Hg (8/10 versus 0/6; p < 0.05), and no disruption of the collagen network occurred in group Ib, regardless of the type of preservation solution. These results suggest that the greatest disruption is caused by barotrauma resulting from an elevated left ventricular end-diastolic pressure after ventricular dysfunction caused by ischemic reperfusion injury.

Adenosine↗
PubMed1993

Tissue-type plasminogen activator (t-PA) lysis of aortic and mitral valve thrombosis.

Valve thrombosis is one of the most serious complications after prosthetic valve replacement. We report the use of tissue-type plasminogen activator (t-PA) in the treatment of a patient with thrombosed aortic and mitral valves. Thrombolysis resulted in immediate hemodynamic improvement and resolution of congestive heart failure, thereby avoiding surgical intervention. Based on our experience, thrombolysis with t-PA is an effective alternative in the treatment of thrombosed prosthetic valves.

Adult↗
PubMed1992

Surgical treatment of cardiac involvement in Takayasu arteritis.

Cardiac involvement is a serious disorder in Takayasu arteritis. Surgical treatment of aortic root and coronary artery lesions due to Takayasu arteritis has many potential difficulties due to its inflammatory nature. We operated on 15 patients with cardiac involvement stemming from Takayasu arteritis. These patients are classified into 3 groups depending on the clinical diagnosis and surgical procedures employed: coronary artery involvement alone--coronary artery bypass grafting (CABG), three patients (group A), aortic regurgitation with intact coronary artery--Aortic valve replacement or modified Bentall's operation, eight patients (group B), and aortic regurgitation with coronary artery involvement g aortic valve replacement or modified Bentall's operation with CABG, (4 patients) (group C). CABG was performed using saphenous vein graft. For aortic valve replacement or replacement of both the aortic valve and ascending aorta, a prosthetic valve or composite graft with Teflon felt flange was fabricated during surgery and treated with fibrin glue before insertion. A double fixation method with reinforcement by a Teflon felt strip was employed for proximal anastomosis of the flanged prosthesis. A button-shaped coronary ostium was directly anastomosed to the composite graft. There was no operative or hospital mortality. One patient died of brain abscess at 6 months after surgery and another patient with CABG required a second operation due to graft failure. Steroid therapy is recommended in cases diagnosed as being in an active stage until the inflammatory signs disappear.

Adult↗
PubMed1992

Modified preservation of all annular-papillary continuity in replacement of the calcified mitral valve.

The technique described here is a modification of the mitral valve replacement with preservation of chordae tendineae for calcified mitral stenosis. After commissurotomy, the middle portion of the anterior leaflet is excised to get two parts with accessible chordal insertion. Each thickened and calcified segment is debrided by means of an ultrasonic tool and then attached to the mural leaflet. Finally mitral valve replacement is carried out. This procedure will extend surgical indication of chordae-sparing methods in mitral valve replacement for mitral stenosis.

Calcinosis↗
PubMed1992

Hibernating myocardium associated with coronary artery dissection and vasospastic angina.

Hibernating myocardium is an uncommon clinical state involving persistently impaired myocardial function. A 61-year-old man was admitted because of vasospastic angina. Coronary angiography revealed coronary artery dissection in the midportion of the right coronary artery, and segmental vasoconstriction was evoked by acetylcholine. In this patient, hibernating myocardium in the dissected region was clearly demonstrated by dipyridamole thallium-201 imaging. This report describes the first documented case of hibernating myocardium associated with coronary artery dissection, and the usefulness of dipyridamole thallium-201 imaging in the assessment of this state. Coronary artery spasm might be relevant to the etiology of coronary artery dissection.

Aortic Dissection↗
PubMed1992

[A long-term result of coronary artery bypass on left coronary ostial stenosis secondary to Takayasu's disease: a case report].

A 37-year-old woman was admitted to our hospital for post operative coronary angiography. At the age of 17, she was diagnosed as having Takayasu's disease and at that time prednisolone was administered. At the age of 22, she was operated on to receive a coronary artery bypass graft (CABG) because of a 95% isolated stenosis in the left coronary ostium. Pathological specimen obtained from the ascending aorta demonstrated a proliferative stage of Takayasu's aortitis. After the CABG, she married and delivered two children, with the inflammation being kept under control by prednisolone. Coronary angiography performed 13 years after the operation proved the saphenous vein graft to the left anterior descending artery to be still patent. To our knowledge, this case has the longest history of a patent CABG used in an operation to correct the ostial stenosis secondary to Takayasu's disease. According to the previous reports we collected, the long-term patency rate of CABG is 78%, whereas that of ostial endarterectomy is unknown. Whether CABG or endarterectomy is better as an operating method for ostial stenosis due to aortitis is still a controversial point. We hope that reports of further examples will be available in order to help make the final decision.

Adult↗
PubMed1991

Structures of mucin-type sugar chains of the galactosyltransferase purified from human milk. Occurrence of the ABO and Lewis blood group determinants.

The mucin-type sugar chains of human milk galactosyltransferase samples purified from two donors with different blood types were released by alkaline borohydride treatment and quantitatively labeled by N-[3H]acetylation. The radioactive oligosaccharides thus obtained were fractionated by high performance liquid chromatography and immobilized lectin chromatography, and their structures were studied by sequential digestion with endo- or exoglycosidases, methylation analysis, and periodate oxidation. It was revealed that the structures of the mucin-type sugar chains of galactosyltransferase are extremely various, and many blood group determinants are expressed on more than 13 different backbone sugar chains. The characteristic features of the sugar chains could be summarized as follows. 1) The sugar chains of both samples are composed of core 1, Gal beta 1----3GalNAc, and core 2, GlcNAc beta 1----6(Gal beta 1----3)GalNAc. 2) One or two N-acetyllactosamine repeating units extend from the core through GlcNAc beta 1----6Gal and GlcNAc beta 1----3 Gal linkages. 3) Blood group determinants are expressed in accord with the blood types of the donors: sample 1 from a donor of blood type O, Lea+b- contains oligosaccharides with Lea and X determinants, and sample 2 from a donor of B, Lea-b- contains those with H, X, Y, and B determinants.

ABO Blood-Group System↗
PubMed1991

Cytokinetic study of aortocoronary bypass vein grafts in place for less than six months.

To evaluate the initial mechanism involving atherosclerotic changes of the saphenous vein graft implanted for coronary artery revascularization in the early stage, immunocytochemical analysis was performed to determine the cell components and kinetics of saphenous vein grafts. Specimens of saphenous vein grafts were obtained from 7 necropsy patients who died at 4 days to 6 months after surgery. Monoclonal antibodies specific for smooth muscle cells (HHF35) and macrophages (HAM56) were used for analysis of the cell components. Migration of macrophages into the intima and the media was observed on the fourth postoperative day. Intimal thickening was characterized by the proliferation of smooth muscle cells, and scattered macrophages were present in the subendothelial layer 1 month after surgery. At 2 months, intimal thickening became prominent and macrophages were recognized circumferentially throughout the layer. At 5 to 6 months, some of the saphenous vein grafts were almost occluded by severe intimal thickening due to proliferation of the smooth muscle cells. Macrophages were also observed both inside and outside of the internal elastic lamina; these are rarely found in the artery. These results suggest that compared with the arterial graft, cytokinesia of the saphenous vein graft contributes to the development of early graft failure because of its rapidity in progression and severity.

Antibodies, Monoclonal↗
PubMed1991

Thoracoscopic diagnosis and treatment of chylothorax after pneumonectomy.

Chylothorax after pneumonectomy was treated successfully by selective application of fibrin glue through a thoracoscope. Conservative therapy for 18 days failed to close the fistula. The site of leakage was identified during thoracoscopy, and fibrin glue was applied under direct vision. Leakage decreased immediately and eventually stopped completely. This technique is less invasive than standard surgical treatment and should be considered in all patients with postoperative chylothorax.

Aged↗
PubMed1991

Immunocytochemical analysis of the atherosclerotic lesion.

We have performed immunocytochemical investigations on the distribution of various cell types and proliferating cells in human atherosclerotic lesions. Studies include fibrocellular tissue response following percutaneous transluminal coronary angioplasty (PTCA) or aortocoronary (A-C) bypass operation using monoclonal antibodies specific to smooth muscle cells, macrophages, endothelial cells, lymphocytes and proliferating cell nuclear antigen (PCNA). All studies were performed on methanol-Carnoy's-fixed, paraffin-embedded tissues. The cellular composition of the following three types of raised lesions were analyzed: 1) fibro-fatty lesions composed almost exclusively of macrophages; 2) fibrous lesions predominantly composed of smooth muscle cells; 3) advanced plaques characterized by complex layers of smooth muscle cells and macrophages with considerable variation from region to region. Also noted were foci of medial and even intimal vascularization subjacent to the more advanced plaques. Cells encountered within the fibrous intimal thickening in the vein graft or fibrocellular tissue response following PTCA were predominantly smooth muscle cells in origin. Some cells were PCNA-positive. These studies demonstrate the application of monoclonal antibody technology to the study of the cellular composition and cell kinetics of human atherosclerotic lesions.

Antibodies, Monoclonal↗