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Biomedical subjects

J Amano

Publications and source records attributed to J Amano.

At least 145 records · Page 8Linked to original sources
PubMed1996

[Mitral reconstruction in patients with infective endocarditis].

Between June 1992 and October 1993, 5 patients with infective endocarditis in native mitral valve underwent open heart surgery. The patients ranged in age from 51 to 64 years and were all males. According to NYHA functional classification, 4 patients were class II and one was class III. Surgery was indicated because of hemodynamic deterioration (2 pts), echocardiographic mobile vegetation with or without previous emboli (2 pts) and both condition (1 pt). Before surgery the patients were afebrile and had negative serum CRP and negative blood cultures for at least one week after adequate medical treatment. The leaflet lesions found in the 5 patients were vegetation (2 pts), perforation (1 pt), calcification (1 pt) and thickening (2 pts). The chordal lesions found were rupture (5 pts) and thickening (1 pt). The infective lesions did not extend to the annulus. The mitral leaflets, including all apparently infectious lesions, were resected in a V-shaped fashion and then valve reconstruction was performed. The resected parts were sutured together with anchoring chordae. The annuloplasty with Teflon-tapes was also added. Postoperatively, all 5 patients showed a dramatic improvement in hemodynamics and endocarditis did not recur during 22 to 38 months of follow-up. The patients who received the repair did not require Warfarin. This study shows that mitral valve repair is an acceptable operation in patients with infective endocarditis, giving the patients better quality of life than mitral valve replacement when (1) infectious lesion are limited to mitral leaflet and chordae, (2) there is no severe calcification of the mitral valve, (3) the infection is healed by the adequate antibiotic therapy.

Endocarditis, Bacterial↗
PubMed1996

[Injury to ascending aorta by cross-clamp--histologic evaluation].

To evaluate the injury to ascending aorta by cross-clamp, the trauma to the vessel wall was examined microscopically and the occlusive intensity of the vascular clamp was measured. Six patients were underwent total replacement of the ascending aorta and the aortic arch for aortic dissection. The ascending aorta and the aortic arch were resected during operation, the clamped regions of the ascending aorta were cut into the four pieces (the distal site, two part of the medial site, the proximal site applied by the vascular clamp) after operation. The four pieces of the ascending aorta were examined microscopically. The occlusive intensity of the vascular clamp were measured at the distal site, the medial site, and the proximal site by the load-measuring scale. The trauma to the vessel wall were classified to three degrees (grade 1 to grade 3). Grade 1 showed the minimal changes--narrowing of interstices between collagen fibers and muscle fibers in the media. Grade 2 showed the moderate changes--decrease of collagen fibers, atrophy and disruption of smooth muscle and elastic fiber in the media. Grade 3 showed the severe changes--disruption of the intima and defluvium of endothelial cells. The occlusive intensity of the vascular clamp were 1.0 kg at the distal site, 1.9 kg at the medial site and 3.6 kg at the proximal site, respectively. In the microscopic examinations, grade 1 changes were most frequent at the distal site, grade 1 and grade 2 changes were observed equally at the medial site, grade 3 change was observed only at the proximal site. The degree of the trauma to the vessel wall becomes severer in proportion to increase of the occlusive intensity of the vascular clamp.

Adult↗
PubMed1995

Attenuation of atrial natriuretic peptide response to sodium loading after cardiac operation.

To evaluate the role of cardiac operation and the atrial appendage in secretion of atrial natriuretic peptide in response to sodium loading, we studied 44 patients who underwent heart operations with (28 patients; group I) or without (16 patients; group II) right atrial appendectomy and 16 patients who underwent lobectomy (group III). Before and after operation 1 ml/kg of 10% NaCl was infused for 15 minutes. Blood samples were taken before NaCl infusion and immediately after infusion and at 60 minutes after infusion. There were no significant changes in hemodynamics or hematocrit level throughout the study. Plasma and urine sodium levels and the fractional excretion of sodium were significantly increased by sodium loading. Before operation, plasma mean atrial natriuretic peptide levels increased markedly in response to sodium infusion in all groups. After operation, this atrial natriuretic peptide response disappeared in groups I and II, but remained present in group III. Elution profiles of plasma atrial natriuretic peptide showed that the major peak coincided with alpha-atrial natriuretic peptide before sodium loading, whereas a beta-atrial natriuretic peptide peak appeared 60 minutes after sodium loading in all groups both before and after operation. The mean plasma arginine vasopressin levels were significantly increased by sodium loading both before and after operation in all groups. Sodium loading decreased the mean plasma aldosterone levels in all groups before operation, but did not after operation in groups I and II. Plasma renin activity and angiotensin II concentrations were not changed by sodium loading. We conclude that atrial natriuretic peptide response to sodium loading is attenuated by cardiac operation irrespective of right appendectomy, but not by lobectomy. Sodium loading augments secretion of beta-atrial natriuretic peptide even in reduced atrial natriuretic peptide response states after heart operations.

Aged↗
PubMed1995

Biochemical properties and intracellular processing of lysosomal cathepsins B and H.

Lysosomal cysteine proteinases of cathepsins B and H were isolated to a homogeneous state from rat liver by employing Sephadex G-75, DEAE-Sephacel, CM-Sephadex, and Mono S column chromatography. Each of the purified cathepsins B and H was demonstrated to be composed of a mixture of a single-chain form and the processed two-chain form upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). To investigate the proteolytic maturation of lysosomal cathepsins B and H, turnover kinetics of these enzymes were studied by comparing the specific radioactivities of the incorporated [3H]leucine into either the single-chain form or two-chain form in vivo. The specific radioactivity derived from each protein band of lysosomal cathepsin H in SDS-PAGE at 1, 3, 6, 12, 24 and 48 h after the injection of a radiolabel showed that the peak of specific radioactivity of the single-chain form of cathepsin H appeared at 6 h and that after 6 h, the radiolabel was sequentially incorporated into the two-chain form, while the radiolabel in the single-chain form started to gradually decrease, suggesting that the single-chain form was processed to generate the mature enzyme after the enzyme was incorporated into the lysosomes. In contrast, in the case of cathepsin B, the appearance of a radiolabel in the single-chain form or in the two-chain form was observed almost concomitantly without time lag, indicating that the processing of cathepsin B occurred very rapidly in the lysosomes.

Amino Acid Sequence↗
PubMed1995

Effect of calcium antagonist diltiazem on renal function in open heart surgery.

STUDY OBJECTIVE: Acute renal failure, which is a serious complication following open heart surgery, has a high mortality rate. Previous reports have shown that the calcium antagonist diltiazem is beneficial either as an adjunct to cardioplegic solution or perioperative treatment for preservation of postoperative cardiovascular function. We studied the effects of diltiazem on renal function, plasma atrial natriuretic peptide levels, and the renin-angiotensin-aldosterone system in patients who had undergone coronary artery bypass grafting. PATIENTS AND MEASUREMENTS: Diltiazem was administered, 0.1 mg/kg, in a bolus injection followed by continuous infusion at a rate of 2 micrograms/kg/min during surgery, and 30 mg through a nasogastric tube at every 8 h. Hemodynamics, renal function, and plasma hormone levels were measured in the diltiazem-treated group (n = 13) and the nontreated group (n = 10). RESULTS: Heart rate, mean arterial pressure, and systemic vascular resistance index in the diltiazem-treated group were significantly lower than those in the nontreated group following cardiopulmonary bypass. Urine volume, creatinine clearance, and free water clearance were well preserved in the diltiazem-treated group. However, plasma renin activity and aldosterone levels were significantly higher in the diltiazem-treated group with the same changes in plasma atrial natriuretic peptide levels. CONCLUSION: Perioperative treatment with diltiazem has a beneficial effect on postoperative renal function, and reflex sympathetic activation induced by peripheral vasodilation activated the renin-angiotensin-aldosterone system.

Aldosterone↗
PubMed1995

[Two cases underwent patch closure and mitral annuloplasty for ventricular septal perforation and mitral regurgitation caused by acute inferior myocardial infarction].

Two cases underwent successful operation for the ventricular septal perforation (VSP) and mitral regurgitation (MR) caused by acute myocardial infarction (AMI) are reported. Patch closure of VSP and mitral annuloplasty (MAP) by Kay-Suzuki method were performed. Location of VSP were posterior ventricular septum and moderate MR were detected in both cases. Case 1 was a 74-year-old man. Four weeks after AMI, patch closure of VSP through right ventricular approach and MAP through trans-atrial approach and also aorto-coronary bypass to left anterior descending artery were performed. Doppler echocardiography was effective to evaluate the severity of VSP and MR. Case 2 was a 69-year-old man. Eight days after AMI, patch closure of VSP and MAP were performed through biventricular approach. Postoperative examination revealed the disappearance of left-to-right shunt and MR in both cases. These cases operated successfully were thought to be rare.

Aged↗
PubMed1994

The effect of sodium concentration on myocardial viability in donor heart preservation using a nondepolarizing solution.

This study examined the effect of different sodium concentrations in a nondepolarizing solution on myocardial viability and functional recovery of the canine donor heart. Isolated canine hearts were preserved for 6 h at 5 degrees C, followed by normothermic reperfusion for 2 h. Dogs were divided into two groups of nine dogs each: group 1 received a nondepolarizing solution with 70 mM Na+ and group 2 with 30 mM Na+. The myocardial Ca2+ concentration at the end of preservation was significantly higher in group 1 than in group 2 and increased after reperfusion in both groups without any intergroup difference. Myocardial concentrations of ATP, ADP, and total adenine nucleotide at the end of reperfusion were significantly higher in group 1 than in group 2. Myocardial cyclic adenosine monophosphate concentration was significantly higher in group 1 than in group 2 at the end of both preservation and reperfusion. The myocardial cyclic guanosine monophosphate concentration in group 1 increased and was higher than in group 2 at the end of preservation, but had returned to normal levels by the end of reperfusion. However, it remained unchanged through preservation and reperfusion in group 2. The left ventricular systolic and diastolic function, assessed by pressure-volume relationship, was better in group 1 than in group 2. Mitochondrial ultrastructural changes were similar. These results suggest that a nondepolarizing solution containing 70 mM Na+ provides better myocardial protection than a solution containing 30 mM Na+.

Adenine Nucleotides↗
PubMed1994

The effects of a temperature below 15 degrees C on the myocardial calcium and ultrastructure in donor heart preservation in a canine model.

The effects of 6-h hypothermic cardioplegic arrest on myocardial biochemical, morphologic, and functional recovery were investigated in two groups of dogs. Group 1 (n = 6) was subjected to hypothermia of 15 degrees C and group 2 (n = 6) was subjected hypothermia of 5 degrees C. Although the myocardial calcium (Ca) concentration was significantly higher at the end of reperfusion in group 2 compared to group 1, the MB-fraction of creatine kinase, mitochondrial aspartate aminotransferase, recovery of left ventricular systolic function, and mitochondrial morphologic integrity were better in group 2 than in group 1. These findings suggest that hypothermia of 5 degrees C in 6-h cardioplegia is not necessarily coupled with interference in myocardial contractility, despite the Ca overload that occurs during reperfusion.

Animals↗
PubMed1994

Effects of cardiac denervation on coronary and systemic circulation.

The effects of cardiac denervation on coronary circulation and systemic hemodynamics were examined in patients who underwent coronary artery bypass grafting for a totally occluded left anterior descending coronary artery. The results in 14 patients who had undergone a combination of bypass grafting and intrapericardial denervation (group I) were compared with those in 19 patients who had undergone only bypass grafting (group II). The heart rate was 110 +/- 4.9 beats/min in group I and 104 +/- 3.7 beats/min in group II after denervation. Although the cardiac index was not significantly different between the two groups, the calculated systemic vascular resistance index of group I (1,358 +/- 111 dynes.s.cm-5.m2) was significantly lower (p < 0.02) than that in group II (1,713 +/- 75 dynes.s.cm-5.m2). The end-diastolic coronary resistance was significantly lower (p < 0.05) in group I (0.59 +/- 0.05 mm Hg.mL-1.min-1) than that in group II (1.04 +/- 0.14 mm Hg.mL-1.min-1), and the end-diastolic graft flow/mean graft flow ratio was 1.56 +/- 0.05 in group I and 1.28 +/- 0.04 in group II (p < 0.01). The plasma norepinephrine concentration in group I (223 +/- 52 pg/mL) was significantly low (p < 0.05) compared with that in group II (328 +/- 39 pg/mL) after denervation. Thus, cardiac denervation may have a beneficial effect on systemic hemodynamics and coronary circulation.

Coronary Angiography↗
PubMed1994

Primary chylopericardium.

To evaluate the surgical treatment of primary chylopericardium, 2 cases of primary chylopericardium are described and previous case reports are reviewed. Enhanced computed tomography combined with lymphangiography is a very reliable diagnostic tool for identifying abnormalities of the thoracic duct and its lymphatic channels connecting to the pericardium. When the course of the thoracic duct was identified exactly, ligation and resection of the thoracic duct with establishment of a pericardial window proved to be the most effective surgical procedure. Because the thoracic duct and the pericardium can be exposed easily, left thoracotomy seems to be the most preferable approach for the operation.

Adolescent↗
PubMed1994

New composite graft repair for patients with and without Marfan's syndrome.

We developed a new composite graft repair technique to prevent the complications associated with Bentall-type procedures. The technique consists of the creation of a double proximal suture line and direct coronary artery implantation as a Carrel patch without wrapping. We retrospectively compared the outcome in patients with Marfan's syndrome (n = 16) and other disorders (aortitis, 11 patients; degenerative disease, 18 patients) who had undergone this procedure. In patients with Marfan's syndrome, there was one hospital death and six deaths during long-term follow-up. Among patients with Takayasu's arteritis, there was one hospital death and one late death. There was one late death in the patients with degenerative disease. No mortality or complications directly related to the surgical procedure occurred in any group. The high late mortality in patients with Marfan's syndrome was primarily due to distal aortic dissection or rupture. Thus, the major complications associated with Bentall-type procedures can be prevented through the use of our new composite graft technique. However, close serial follow-up, careful blood pressure control, and early detection and treatment of distal recurrence are mandatory in the postoperative management of patients with Marfan's syndrome.

Adult↗
PubMed1994

Long-term results of reconstructive surgery for acquired valve disease: evaluation of mitral and aortic valvuloplasty.

To evaluate the long-term results of reconstructive surgery for mitral and aortic valve diseases, 58 patients treated with mitral valvuloplasty (MVP) and 18 patients with aortic valvuloplasty (AVP) were considered. In the MVP group simple annuloplasty was performed in 16 cases, tape annuloplasty in 39 cases, and mitral valve extension with homopericardium in 3 cases. In the AVP group a combination of slicing, commissurotomy, and commissuroplasty was performed in 15 cases and aortic valve extension in three. There was one operative death in the AVP group, and one late death in the MVP group. The percentage of patients who had no complications related to reconstructive surgery after 17 years was 88% in the MVP group, and 81.7% in the AVP group. Only three patients in the MVP group, and one in the AVP group required reoperation after the reconstruction. Thus, reconstructive surgery should be utilized, whenever possible, in the treatment of valvular disease, even of the aortic valve.

Adolescent↗
PubMed1994

Rupture of inferior phrenic artery aneurysm. An unusual complication of mesenteric arteritis due to postcoarctectomy syndrome.

Postcoarctectomy syndrome was developed in a boy with Williams syndrome. Angiogram revealed widespread changes of visceral arteries and extravasation of the contrast material from the right inferior phrenic artery. Emergency laparotomy was successful. This unusual complication makes clear that the mesenteric arteritis after coarctectomy can cause aneurysm with a risk of rupture.

Abnormalities, Multiple↗
PubMed1994

Atrial natriuretic peptide response to unilateral pulmonary artery occlusion.

To test the hypothesis that neural mechanisms evoked by unilateral pulmonary artery occlusion (UPAO) affect the release of atrial natriuretic peptides (ANP) from the heart, hemodynamics and levels of plasma ANP and cyclic guanosine monophosphate (c-GMP) were studied in 11 patients with lung cancer. The UPAO induced a significant rise in heart rate by 5.3 percent, increased mean pulmonary artery pressure by 31 percent without affecting right atrial pressure, and decreased plasma ANP levels in the coronary sinus by 17.4 percent (p < 0.05) from 202.5 +/- 27.1 pg/ml to 167.2 +/- 27.4 pg/ml. Atropine sulfate (0.04 mg/kg) injection increased the heart rate by 38.2 percent (p < 0.01), reduced the stroke volume index by 25.1 percent, decreased coronary sinus ANP levels from 198.5 +/- 16.4 pg/ml to 124.8 +/- 19.6 pg/ml (p < 0.01), and decreased coronary sinus plasma c-GMP levels from 4.6 +/- 0.5 pmol/ml to 3.1 +/- 0.4 pmol/ml (p < 0.05). After atropine pretreatment, UPAO induced a significant (p < 0.05) increase of 34.8 percent in the coronary sinus ANP level. Thus, it is concluded that in UPAO, the secretion of ANP from the heart is modulated partly by the autonomic nervous system.

Adenocarcinoma↗
PubMed1994

Salutary effect of reduced glutathione on renal function in coronary artery bypass operation.

BACKGROUND: Renal dysfunction and acute renal failure are serious complications of open heart operations. Previous reports have suggested beneficial effects of exogenous glutathione for preservation of renal function after ischemic renal injury. We prospectively studied the effect of perioperative administration of glutathione on renal function in patients who underwent coronary artery bypass operation. STUDY DESIGN: Two hundred mg per kg of glutathione was administered to the treated group (n = 10) before cardiopulmonary bypass, and on the first and second postoperative days. The control group was administered placebo in the same volume. Hemodynamics, renal function, and plasma hormone levels were measured consecutively. RESULTS: In the glutathione group, the mean arterial pressure and systemic vascular resistance index were lower than in the control group. Urine volume, creatinine clearance, and renal excretory index were well preserved in the group treated with glutathione. Moreover, the fractional excretion of sodium was lower and urine and plasma osmolarity was higher in the group treated with glutathione. No differences in plasma renin activity, angiotensin II, or aldosterone concentrations between the two groups were observed. CONCLUSIONS: Perioperative glutathione treatment has a salutary effect on perioperative renal function through effects on both renal hemodynamics and tubular mechanism.

Acute Kidney Injury↗
PubMed1994

[A case of micro-metastatic lung adenocarcinoma into adenoma of the thyroid].

In a case of 46-year-old woman, small nodules appeared in the anterior neck which was diagnosed as follicular adenoma of the left lower lobe of the thyroid. Four months before, she experienced resection of the lung and three courses chemotherapy of MVP for stage IIIb well-differentiated lung adenocarcinoma. Pathologically, micro-metastatic lung adenocarcinoma was found in the adenoma. It is very rare occurrence for lung carcinoma to metastasize into adenoma of the thyroid. But when tumors of the anterior neck are found in a patient of lung carcinoma, thyroid tumor must be considered for differential diagnosis.

Adenocarcinoma↗
PubMed1994

[CT guided percutaneous needle biopsy of mediastinal lymph nodes for staging of primary lung carcinoma].

In cases of primary lung carcinoma, diagnosis of metastatic mediastinal lymph nodes using computed tomography (CT) is usually difficult, and mediastinoscopy is highly invasive for patients. By using CT guided percutaneous needle aspiration technique, we diagnosed the metastasis to mediastinal lymph nodes in three cases of primary lung carcinoma. In this method, percutaneous biopsy was easily performed even in obesed patient, and metastatic lymph nodes were differentiated from large vessels by using enhanced CT to avoid dangerous punctures. Furthermore, biopsy of almost all mediastinal lymph nodes may be feasible by using both anterior and posterior approach. This method seems to be very useful for the diagnosis of the staging of primary lung carcinoma.

Adenocarcinoma↗