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Biomedical subjects

J Amano

Publications and source records attributed to J Amano.

At least 181 records · Page 10Linked to original sources
PubMed1991

Coronary artery involvement in Takayasu's arteritis. Collective review and guideline for surgical treatment.

Coronary artery disease is a rare involvement of Takayasu's arteritis. From 1961 to 1989, 63 patients, including our five, have been reported to undergo operations for coronary artery disease resulting from Takayasu's arteritis. Most of the patients were Japanese (86%) and female (86%). The initial clinical manifestation was angina pectoris in 71%. Among 92 lesions, coronary ostia were most frequently involved (73%) followed by nonostial proximal lesions (18.5%). Forty-two of 62 (67.7%) ostial lesions of the left main coronary artery had more than 90%, or complete, stenosis. Aortic regurgitation was associated in 28 patients (44.4%). Myocardial revascularization was performed in 49, and transaortic endarterectomy in 12. Concomitant aortic valve replacement was done in 16 patients. Operative mortality was five (7.9%), and late deaths were reported in three patients. Postoperative steroid therapy was performed in 22. Operation was repeated in two patients because of graft failure. Thus coronary artery disease resulting from Takayasu's arteritis should be suspected in young Asian women with angina pectoris. The timing preferred for surgical intervention is during an inactive phase. Two procedures are commonly chosen for surgical intervention, either transaortic endarterectomy or coronary revascularization with vein grafts. Postoperative steroid therapy is strongly recommended to those patients who are operated on in the clinically or histologically active stage.

Adult↗
PubMed1991

[From Bentall's operation to its modification by Suzuki: improved technique for replacement of both aortic valve and ascending aorta].

To improve the result of surgery for replacement of both aortic valve and ascending aorta, we developed a new technique which is characterized as follows. 1) The composite graft is made during surgery according to the operative findings with tilting disc valve and very low porosity woven Dacron graft. 2) Proximal anastomosis is reinforced by double fixation method. 3) Coronary arteries are reimplanted directly into the graft as a Carrel patch. Thirty-four patients underwent this surgery with no operative death. One died in the hospital and 4 died in the late stage unrelated to the surgical technique. We recommend this method as a new standard technique for replacement of both aortic valve and ascending aorta.

Aorta↗
PubMed1991

[Investigation of limulus test during and after cardiopulmonary bypass. Part II. Effect of washing of the bypass circuit].

Previously we reported the presence of Limulus positive substance (LPS) in blood and urine for several days following cardiopulmonary bypass (CPB), and foreign particles in the primining fluids. The purpose of this study was to evaluate the effect of washing of the CPB circuit on appearance of LPS and to define the nature of it. Semi-quantitative Limulus test was performed in patients using washed CPB circuit (n = 54) and without washing (n = 41). LPS in the blood were negative in all patients before CPB. LPSs in the priming fluids did not disappear after washing, however the amounts of it in the blood were significantly lower than those without washing. Especially at second postoperative day. Limulus test were positive in 10% of patients with washed CPB circuit and 60% of those without it (p less than 0.01), and all the urine samples of patients with washed CPB circuit were negative to Limulus test at 1st postoperative day. The number of foreign particles decreased in parallel with the smaller pore size of the filter. Since reactions of Pregell to ethylene oxide gas, ethylene chlorohydrin and ethylene glycol were negative, ethylene oxides did not seem to be the LPS. These results indicate the superiority of employment of washed CPB circuit with micropore filter. However, further exploration is still mandatory to elucidate the LPSs.

Adolescent↗
PubMed1990

The characteristics of coronary artery revascularization in aged patients.

This study was undertaken in order to clarify the clinical characteristic features and surgical results of coronary artery bypass grafting (CABG) in patients over 65 years of age (group III, n = 43). These patients were compared with 2 other groups of patients, one aged between 50 and 59 years (group I, n = 88) and another aged between 60 and 64 years (group II, n = 54), with respect to mortality, morbidity and late survival. CABG was performed with the saphenous vein under cold K-Mg-cardioplegia with systemic hypothermia. The hospital mortality was 2.3, 3.7, and 4.7 per cent in groups I, II and III, respectively, although no operative mortality was noted in any group. The number of coronary artery lesions increased with age, however, the left ventricular ejection fraction was relatively better preserved in the aged patients than in the younger ones. The 5-year survival rates were 93.4, 95.1 and 96.9 per cent in groups I, II and III, respectively, with most of the late deaths occurring within a year after CABG in each group. In the aged patients, postoperative functional recovery was delayed in the liver and kidney, and postoperative psychosis was not infrequent. The results of this study, indicating a low operative mortality and satisfactory late survival rate, thus strongly support CABG for the aged. Nevertheless, the prevention of postoperative complications is also extremely important for reducing hospital mortality.

Aged↗
PubMed1990

Altered glycosylation of human chorionic gonadotropin decreases its hormonal activity as determined by cyclic-adenosine 3',5'-monophosphate production in MA-10 cells.

Human chorionic gonadotropin (hCG) purified from pooled urine of normal pregnant women contains four asparagine-linked sugar chains and four mucin-type sugar chains. The structures of asparagine-linked sugar chains of this hormone are constant and site-specific. hCGs obtained from the urine of patients with invasive mole or choriocarcinoma have quite different sets of oligosaccharides although the primary structures of the polypeptides and the numbers of the sugar chains are the same as those of normal hCG. In order to examine the biological activities of these hCGs with altered glycosylation, we measured the amount of cAMP produced in a murine Leydig tumour cell line, MA-10, after incubation with the hCG samples. The extent of sialylation of oligosaccharides in the three hCG samples used in this study were 88% in normal hCG, 82% in invasive mole hCG and 63% in choriocarcinoma hCG. The hormonal activity of invasive mole hCG was slightly lower while that of choriocarcinoma hCG was significantly (P less than 0.01) lower than that of normal hCG. Complete desialylation induced remarkable loss of full activities in all the samples. However, the hormonal activities of the three samples were different even after desialylation. The full activities of the desialylated samples of invasive mole hCG and choriocarcinoma hCG were 78 and 65% of that of desialylated normal hCG. These results indicated that the structures of the neutral oligosaccharide portion are also important for the expression of full hormonal activity.

Animals↗
PubMed1990

Experimental studies on vein graft atherosclerosis (I). Histochemical studies using monoclonal antibodies for smooth muscle cells and macrophages.

Vein graft atherosclerosis characterized by smooth muscle cell proliferation has become the most serious cause of late graft failure. This study was designed to elucidate why marked histological differences occur in atherosclerotic changes between the vein graft and the artery. Fourteen rabbits underwent autonomous transplantation of femoral vein sections (10-12 mm in length) into femoral arteries on the same side. They were then kept on either commercial or 1% cholesterol diet. At 4, 8, 15 and 30 weeks after the operation, they were sacrificed and histochemical & immunocytochemical studies on atherosclerotic changes found in graft and arteries were carried out, using monoclonal antibodies for macrophages (RAM 11) and smooth muscle cells (HHF 35). Atherosclerotic lesions found in arteries of rabbits fed by cholesterol for more than 8 weeks were characterized with the accumulation of macrophage-derived foamy cells with fibrous caps. In contrast, the lesions found in the grafts of the same rabbits were occupied with proliferating smooth muscle cells and very few macrophages. Furthermore, in lesions of the vein grafts of rabbits fed cholesterol for 4 weeks, macrophages were rather frequently encountered in the bottom of the lesions and/or its medial layer, scattering and sometimes forming mass-lesions. These results may suggest structural differences in the vein with its thin and sparse internal elastic lamina and with its thin medial layer, allowing macrophages to pass easily through the elastic lamina and scatter into the media. This may be the reason why autonomous vein graft atherosclerosis is mainly composed of proliferated smooth muscle cells.

Animals↗
PubMed1990

[A case of lung cancer with mediastinal tumor].

A 72-year-old female underwent surgical resection of lung cancer and mediastinal tumor. Abnormal shadows on the chest roentgenogram were incidentally detected by the regular health screening. The lung cancer existed in the left upper lobe, and the mediastinal tumor existed in the posterior mediastinum along left side of the spines. Serum CEA level was 299 ng/ml by enzyme immunoassay method. We judged the lung cancer as being in Stage I (T2 N0 M0), and the mediastinal tumor as benign neurogenic tumor unrelated to the lung cancer through detailed examination. Surgical resection of both tumors was performed through left thoracotomy, and the surgical procedure was curative operation. Pathological examination revealed the lung cancer was moderately differentiated adenocarcinoma and the mediastinal tumor was Schwannoma. Eight months after surgery, serum CEA level is 1.1 ng/ml without evidence of recurrence. This experience suggested us that a mediastinal tumor accompanied by lung cancer is not necessarily metastatic tumor, and that curative operation may be possible in these cases.

Adenocarcinoma↗
PubMed1989

Sialic acids, but not their linkage to galactose residues, are required for full expression of the biological activity of human chorionic gonadotropin.

One of the characteristic features of the asparagine-linked sugar chains of human chorionic gonadotropin (hCG) is that their sialic acid residues occur exclusively as the Neu5Ac alpha 2----3Gal group. In order to determine whether this sialic acid linkage is important for the functional role played by the sugar moiety of hCG or not, isomeric hCG containing the Neu5Ac alpha 2----6Gal group was prepared and its hormonal activity in vitro was investigated. On addition of the isomeric hCG to the culture medium of a murine Leydig tumor cell line, it was found that it shows the same hormonal activity as natural hCG.

Adenylyl Cyclases↗
PubMed1989

Surgical consideration of aortitis involving the aortic root.

Most serious complications after aortic valve replacement (AVR) in Takayasu's and Behçet's diseases are repeated detachment of the prosthetic valve and formation of a false aneurysm. Therefore, special consideration of the surgical treatment of aortitis involving the aortic root is required. Fifteen patients (12 with Takayasu's disease and three with Behçet's disease) underwent various surgical procedures, depending on the pathological changes in the aortic valve and the aortic root and on the degree of involvement of the coronary artery. Group 1 patients had coronary artery involvement alone and underwent coronary artery bypass grafting (CABG) (n = 3); group 2 patients had aortic regurgitation with an intact coronary artery and underwent AVR or a modified Bentall procedure (n = 7); and group 3 patients had aortic regurgitation with coronary artery involvement and underwent AVR, a modified Bentall procedure, or translocation with CABG (n = 5). A prosthetic valve or composite graft with a Teflon felt flange at the sewing ring was fabricated during surgery by exact measurement of the sizes of the aortic annulus and distal aorta and treatment with fibrin glue before insertion. The double-fixation method with reinforcement by a Teflon felt strip was employed for anastomosis of the flanged prosthesis. The button-shaped coronary ostium was directly anastomosed to the composite graft. One patient required translocation with CABG because of a deteriorated annulus. There were no operative or hospital deaths. One patient died of a brain abscess at 6 months after surgery, and another patient who underwent CABG required CABG reoperation due to graft occlusion. We recommend postoperative steroid therapy in patients who are diagnosed as being in the active stage of the disease until inflammatory signs disappear.

Adult↗
PubMed1989

[Investigation of Limulus test during and after cardiopulmonary bypass--analysis of Limulus positive substance and particles in the cardiopulmonary bypass circuit].

Patients undergoing heart surgery with cardiopulmonary bypass (CPB) frequently have positive Limulus test without any remarkable signs of endotoxemia. CPB circuit could be one of the possible causes of this phenomenon, but the exact mechanism has not been studied. Accordingly, a prospective study was made in 41 patients undergoing heart surgery with CPB. Limulus test were performed on the samples of priming fluids of CPB including the plasma and urine of those patients during and after surgery. Besides the Limulus test, the CPB fluids were analysed by the false positive test. Microscopic examinations were carried out on the priming fluids before and after using a 40 microns filter during recirculation without washing the CPB circuit and the fluid from a 4 microns filter been washed by 2000 ml of Martose-10 in order to find out the presence of any foreign particles in the CPB circuit. The size and the number of particles were measured by coulter counter. The studies revealed the following facts, 1) Limulus test; most of the samples from priming fluids (31/35), plasma circulating the CPB (36/36), urine during CPB (22/25) and plasma (34/35) and urine (21/30) just after the surgery revealed positive. However, only 4 samples from plasma at 3POD and 2 samples from urine at 2POD revealed positive, 2) false positive test of the samples from priming fluids was negative meaning the Limulus positive substances are not endotoxin, 3) under microscopic analysis and coulter counter, there were about 40 particles over 50 microns per ml of priming fluids before washing the CPB circuit.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1989

[Successful resection of the right atrial myxoma with excessive tumor vascularity in a elderly patient].

A 72-year-old female underwent successful resection of a giant right atrial myxoma. The patient had slight cough with abnormal cardiac silhouette and elevated ESR. The diagnosis of right atrial myxoma was established by echocardiography and angiography. Venacavography revealed huge mass which occupied in the entire right atrium. This tumor was perfused by well developed feeding arteries arising from both right and circumflex coronary arteries, and showed rich tumor vascularity. This tumor was resected with the interatrial septum and the free wall of the right atrium which were attached with tumor. Interatrial septal defect was closed with a Teflon fabric patch and the defect of right atrial free wall was approximated by direct closure with Z-plasty. Postoperative course was uneventful. Pathological examination showed myxoma without invasion into the resected septum and atrial wall. It is important to prevent tumor embolization to the pulmonary artery or strangulation into the right ventricle during surgery on this type of huge right atrial myxoma.

Aged↗
PubMed1988

Comparative study of the mucin-type sugar chains of human chorionic gonadotropin present in the urine of patients with trophoblastic diseases and healthy pregnant women.

Human chorionic gonadotropins (hCGs) highly purified from the urine of patients with trophoblastic diseases and of healthy pregnant women contain approximately four mucin-type sugar chains in one molecule. The structures of these sugar chains were studied comparatively by using a new sensitive method to obtain mucin-type sugar chains quantitatively as radioactive oligosaccharides from a small amount of glycoproteins. The mucin-type sugar chains of all hCGs include sialylated and nonsialylated Gal beta 1----3GalNAc and Gal beta 1----4GlcNAc beta 1----6(Gal beta 1----3)GalNAc. In the case of normal hCG and hydatidiform mole hCG, oligosaccharides containing the tetrasaccharide core occupy approximately 10% of the total mucin-type sugar chains. The ratio of the tetrasaccharide containing oligosaccharides is increased prominently to approximately 60% in choriocarcinoma hCG. The proportion in invasive mole hCG was also increased, but less than the proportion of choriocarcinoma hCG.

Acetylation↗
PubMed1988

Biosynthesis of lysosomal cathepsins B and H in cultured rat hepatocytes.

The biosynthesis of lysosomal cysteine proteases, cathepsins B and H, was investigated by using pulse-chase experiments in vivo in primary cultures of rat hepatocytes. Cathepsins B and H were isolated from either total cell extracts or culture medium labeled with [35S]methionine by immunoprecipitation and analyzed for their molecular forms. Within 60 min of chase, cellular proforms of cathepsins B of 39 kDa and H of 41 kDa were converted to single-chain form cathepsins B of 29 kDa and H of 28 kDa, respectively, and persisted as these forms even after 12-h chase periods. The proforms of cathepsins B and H derived from pulse-labeling experiments showed complete susceptibility to endoglycosidase H treatment, indicating that these proenzymes bear high-mannose-type oligosaccharides at the stage of initial events of biosynthesis. In the presence of tunicamycin, unglycosylated proenzymes of cathepsins B of 35 kDa and H of 34 kDa were found to be secreted into the extracellular medium without undergoing proteolytic processing. Furthermore, in the presence of swainsonine, a potent inhibitor of Golgi mannosidase II, considerable amounts of the proenzymes were secreted and accumulated in the medium during chasing periods. These results suggest that the oligosaccharide moiety of these enzymes would be necessary for the intracellular sorting mechanism. In monensin-treated cells, the conversion of intracellular proenzymes to mature enzymes was significantly inhibited and the proenzymes were secreted into the medium. In the presence of chloroquine or ammonium chloride, proteolytic processing of the proenzymes was completely prevented and the enhanced secretion of proenzymes was observed. These results suggest that in the presence of lysosomotropic amines the intracellular sorting of proenzymes might not occur properly during biosynthesis.

Alkaloids↗
PubMed1988

Immunocytochemical investigation of atherosclerotic changes observed in aortocoronary bypass vein grafts using monoclonal antibodies.

The authors have performed immunocytochemical surveys on atherosclerotic changes observed in saphenous vein aortocoronary bypass grafts, comparing the changes occurring in coronary and aortic lesions. The two monoclonal antibodies used in this study were obtained by T. Tsukada. One of them, named HHF35, exhibited specificity to smooth muscle cells; the other, named HAM56, was specific to macrophages. These immunocytochemical studies clearly demonstrated that cells encountered within the fibrous intimal thickening in the vein graft were inevitably smooth muscle cell in origin. Macrophages were seldom seen in the grafts examined. In contrast to vein grafts, macrophages were noted within the intima of all specimens from arterial atherosclerotic lesions obtained from the same patients. These studies suggest a difference in the progression of intimal thickening between the venous graft and the arterial atherosclerotic lesions.

Antibodies, Monoclonal↗
PubMed1988

Role of protease inhibition in myocardial preservation in prolonged hypothermic cardioplegia followed by reperfusion. Effect of aprotinin in an experimental model.

The effects of aprotinin on canine myocardium subjected to cardioplegia and global ischemia for 4 hours and then reperfused for 1 hour were investigated. Lysosomal and mitochondrial enzymes and cyclic nucleotides (adenosine cyclic monophosphate and guanosine cyclic monophosphate) were measured in coronary sinus blood. Aprotinin was given intravenously before cardiopulmonary bypass at total doses of 10 X 10(3) kallikrein units per kilogram (group A, six dogs) and 20 X 10(3) KU/kg (group B, six dogs). In group A, three dogs survived but with poor cardiac function; all dogs in group B survived and had better cardiac function. Lysosomal (N-acetyl-beta-D-glucosaminidase) and mitochondrial (aspartate aminotransferase) enzymes in coronary sinus blood at 60 minutes of reperfusion were significantly (p less than 0.05) lower in group B than in group A. In both groups, guanosine cyclic monophosphate was significantly (p less than 0.01) lower during reperfusion than before cardiopulmonary bypass; however, the values were significantly (p less than 0.05) higher in group B than in group A. Serum adenosine cyclic monophosphate was lower during reperfusion than before bypass in both groups, but it recovered during reperfusion in group B. Myocardial adenosine triphosphate was well preserved in both groups but creatine phosphate was decreased (p less than 0.01) in group A. These results suggest that aprotinin at a dose of 20 X 10(3) KU/kg may be effective in preserving myocardial viability and function after prolonged cardioplegia.

Acetylglucosaminidase↗