Biomedical subjects

M Sunamori

Publications and source records attributed to M Sunamori.

At least 55 records · Page 3Linked to original sources

PubMed1997

[Thoracoscopic resection of mediastinal parathyroid adenoma with cyst and hyperparathyroidism--a case report].

A 51-year-old woman was admitted because of general fatigue assumed to be due to climacteric disturbance. Laboratory examinations suggested a diagnosis of hyperparathyroidism based on high serum levels of Ca, intact PTH, and high-sensitivity PTH. No abnormalities were found in the cervix. Chest X-ray films and CT scans showed a mass measuring 4 cm in the right postero-upper mediastinum. The tumor was positive on a parathyroid scintigram, and was diagnosed as a mediastinal parathyroid adenoma with hyperparathyroidism. Operative findings showed a tumor surrounded by the superior vena cava, vagus nerve, azygos vein, and brachiocephalic artery. Careful resection of the hypervascular tumor from surrounding tissues was performed using a thoracoscopic technique alone. The postoperative course was uneventful. Serum values of Ca, intact PTH, and high-sensitivity PTH decreased to within normal ranges. after surgery. Pathohistological study confirmed the diagnosis of parathyroid adenoma including a cyst caused by degeneration of the tumor.

Adenoma↗

PubMed1996

Effect of the potassium-channel opener nicorandil as an adjunct to cardioplegia on myocardial preservation in isolated rabbit hearts.

We studied the effect of nicorandil on the hemodynamic, biochemical, and ultrastructural changes in rabbit hearts (n = 50) rendered cardioplegic with a single injection of Bretschneider's HTK solution over 30 min or 60 min at 37 degrees C or 15 degrees C, followed by reperfusion at 37 degrees C for 60 min. Particular attention was focused on the aspects of dose-response relationship, temperature sensitivity, and ischemic tolerance. Isolated hearts were prepared for modified Langendorff circulation using modified Krebs-Henseleit bicarbonate solution bubbled with a 95% O2(-5)% CO2 gas mixture, to which nicorandil (0, 0.1, 1, and 5 mM) was added. The optimal concentration of nicorandil was 1mM, which increased the recovery of left ventricular (LV) function, affecting coronary flow and the myocardial cyclic adenosine monophosphate, but not the myocardial concentrations of adenine nucleotide compounds or total calcium. These effects were abolished by the addition of glibenclamide to the HTK, but they were not diminished by a high potassium (K+) concentration of 20mM. The addition of nicorandil 1mM to the HTK at 15 degrees C did not improve the recovery of LV function. Our result suggested that nicorandil used adjunctly prevents LV functional depression after 30min, and possibly 60min of cardioplegia at 37 degrees C, and that this effect is not disturbed by a high K+ concentration up to 20 mM. However, nicorandil has temperature sensitivity whereby it loses its efficacy at 15 degrees C.

Animals↗

PubMed1996

The effect and pharmacokinetics of nafamostat mesilate adjunct to cold nondepolarizing cardioplegia in a canine model of cardiac preservation.

We examined the effects of nafamostat mesilate (NM) on myocardial, biochemical, and functional changes in canine hearts. An isolated heart was preserved for 6 h at 5 degrees C and then reperfused for 2 h at 37 degrees C. NM wa added to the cardioplegic solution. At concentrations of both 10(-7) M (n = 8) and 10(-6) M (n = 6), NM was able to maintain myocardial cyclic adenosine monophosphate (cAMP) at a normal level and to reduce guanosine monophosphate (cGMP) concentrations at the end of both preservation and reperfusion. The serum N-acetyl-b-D-glucosaminidase (NAG) concentration during reperfusion was lower in hearts treated with NM 10(-6) or 10(-7) M than in those without NM (P < 0.05). Although NM failed to preserve myocardial concentrations of adenine nucleotide compounds, NM 10(-7) M maintained the +/- dp/dt of the left ventricle after reperfusion at the same level as in the nonischemic control group and better than NM 10(-6) M or no NM (P < 0.05). Myocardial uptake of NM 10(-5) M (higher concentration) was 55% +/- 8% (6-h preservation) and 29% +/- 15% (2-h reperfusion). We conclude that NM 10(-7) M adjunct to non-depolarizing solution does not preserve myocardial adenine nucleotide concentrations but does facilitate the recovery of left ventricular function. NM 10(-5) M (higher concentration) seems to have a high affinity for the myocardium and may depress the recovery of left ventricular function.

Adenine Nucleotides↗

PubMed1996

Effect of phosphodiesterase III-inhibitor (E-1020) adjunct to Bretschneider's HTK cardioplegic solution on myocardial preservation in rabbit heart.

We examined the hypothesis that an increase in the myocardial cyclic adenosine monophosphate (cAMP) by a phosphodiesterase III inhibitor, E-1020, may ameliorate the hemodynamic and biochemical changes in rabbit hearts after cardioplegic arrest, and that this enzyme-mediated process is temperature-sensitive. Sixty-one male Japanese white rabbits weighing 2.8 to 3.5 kg were used. Isolated hearts were prepared for modified Langendorff circulation using modified Krebs-Henseleit bicarbonate solution bubbled with a 95% O2-5% CO2 gas mixture. Thirty or sixty minutes of cardioplegia at 37 degrees C, or thirty minutes of cardioplegia at 15 degrees C was followed by normothermic reperfusion for 60 minutes. E-1020, 0.1 mmol/L was added to the cardioplegic solution (Bretschneider's HTK solution). The left-ventricular function was measured with a latex balloon placed in the left-ventricular cavity. The myocardial cAMP was higher, the total myocardial calcium was lower in hearts with E-1020 than in hearts with HTK alone (p < 0.05). E-1020 at 0.1 mmol/L did increase the myocardial concentration of cAMP and the functional recovery, and prevented the increase in the myocardial total calcium. Temperature affected the myocardium to preserve myocardial concentrations of adenine nucleotide compounds and cAMP. Our results suggest that a 0.1 mmol/L E-1020 adjunct to HTK solution at 37 degrees C completely prevents left-ventricular functional depression during 30 min of cardioplegia induced with non-oxygenated HTK, but decreases its potential efficacy at 15 degrees C. The protective effects disappear if the ischemic period lasts 60 min at 37 degrees C.

Animals↗

PubMed1996

Uptake of indium-111-anti-intercellular adhesion molecule-1 monoclonal antibody in the allografted rat lung during acute rejection.

BACKGROUND: Although many methods for detection and quantification of allograft rejection of the lung have been explored, only histologic diagnosis by lung biopsies has gained widespread acceptance. To examine whether indium-111-anti-intercellular adhesion molecule-1 monoclonal antibody imaging can noninvasively detect acute lung rejection, we measured the uptake of this radiopharmaceutical in lung tissue and with scintigraphy in orthotopically transplanted rat lungs. METHODS: The left lung transplant model was used with Lewis- to Wistar-King rat allografts and Lewis isograft controls. Lungs were harvested 2,3,4,5,6, and 7 days after transplantation. The transplanted and native lungs were removed 24 hours after injection of the radiotracer, weighed, and counted in a gamma well counter; uptake ratios of the transplanted or native lungs were then calculated, and scintigraphy was performed. RESULTS: Histologic rejection scores by the grading system of the International Society for Heart and Lung Transplantation at 2,3,4,5,6, and 7 in the allografts were 1.2 +/- 0.2, 2.3 +/- 0.6, 3.0 +/- 0.5, 3.7 +/- 0.4, and 4, and 4, respectively. The uptake ratios of the allografts 3,4, and 5 days after transplantation were significantly higher than the values of the respective isografts and correlated with histologic rejection grades. However, 6 days after transplantation, uptake ratios of allografts decreased and did not correlate with histologic grades. On days 3,4, and 5 after transplantation, the tracer uptake within the allografts was visualized by means of scintigraphy. CONCLUSIONS: We conclude that indium-111-anti-intercellular adhesion molecule-1 monoclonal antibody increased during mild to moderate acute lung rejection. An abnormal scintigram with this radiotracer suggests that lung biopsy should be performed to exclude lung rejection.

Animals↗

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↗

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

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 effect of betamethasone on myocardial viability during cold cardioplegia in canine donor heart preservation.

This study examined the effect of betamethasone on myocardial viability of reperfused isolated canine hearts following a 6-h hypothermic cardioplegia. The dogs were divided into two groups: group I (n = 9) received nondepolarizing cardioplegia containing betamethasone 250 mg/l while group II (n = 7) was administered cardioplegia without betamethasone. The myocardial concentrations of calcium, ATP, ADP, total adenine nucleotide, cyclic adenosine monophosphate (cAMP) and cyclic guanosine monophosphate (cGMP) were identical in the two groups throughout the experiment. The coronary sinus plasma concentrations of MB fraction of creatine kinase (MB-CK), cAMP and cGMP after 2h of reperfusion were significantly lower in group I than in group II. The myocardial mitochondrial ultrastructure, as assessed by semiquantitative morphometry, was found to be significantly better preserved in group I than in group II at the end of both preservation and reperfusion. In addition, the left ventricular end-systolic pressure volume relation (ESPVR) showed a higher slope and lower intercept in group I than in group II. These results suggest that the addition of betamethasone to nondepolarizing cold cardioplegia enhances myocardial protection via membrane stabilization without affecting the adenine nucleotide metabolism.

Animals↗

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

The myocardial distribution and plasma concentration of carnitine in patients with mitral valve disease.

The myocardial distribution and concentration of carnitine and its fractions was studied in 11 patients with mitral valve disease not associated with congestive heart failure (CHF). The plasma concentration of carnitine was found to be identical to the normal values documented in the literature. The left ventricular papillary muscle had the highest concentrations of total, short-acyl, long-acyl, and free carnitine, being significantly higher than those of the right ventricle, while the right atrial appendage had the lowest values of all fractions of carnitine. The proportion of long-acyl carnitine to total carnitine was significantly greater in the left ventricle than in either the right atrium or the atrial septum, and other carnitine fractions were identical in all cardiac chambers. Our results suggest that in the compensated heart with mitral valve disease, carnitine and its fractions are greatest in the left ventricle in the muscles of all cardiac chambers, and that long-acyl carnitine is most likely to be linked to the cardiac muscle demanding a higher cardiac performance.

Carnitine↗

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

Effect of pinacidil on rat hearts undergoing hypothermic cardioplegia.

We studied the effect of pinacidil, a potassium-channel opener, on the hemodynamic, biochemical, and ultrastructural changes in rat hearts undergoing hypothermic cardioplegia. Fifty-four male Wistar rats weighing 250 to 300 g were used. Isolated hearts were prepared for modified Langendorff circulation in the working mode using modified Krebs-Henseleit bicarbonate solution bubbled with a 95% O2 and 5% CO2 gas mixture. Eighty minutes of cardioplegia at 25 degrees C was followed by normothermic reperfusion for 30 minutes. Pinacidil, 5, 10, or 50 mumol/L added to the cardioplegic solution, did not affect heart rate, but is significantly improved the recovery of aortic flow as compared with controls (88.1% +/- 4.3 [5 mumol/L]; 83.2% +/- 8.5% [10 mumol/L]; 90.3% +/- 5.3% [50 mumol/L] compared with 55.6 +/- 4.3% [control]; p < 0.05). Administration of pinacidil during reperfusion did not further enhance the recovery of aortic flow. The dose-response curve of aortic flow to the pinacidil concentrations was flat from 5 to 50 mumol/L. However, preservation of myocardial adenosine triphosphate and calcium concentrations and mitochondrial morphology suggested that the optimal concentration of pinacidil cardioplegia is 10 mumol/L.

Animals↗

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

The effect of L-carnitine on myocardial protection in cold cardioplegia followed by reperfusion.

We studied the effect of exogenous L-carnitine on myocardial viability and carnitine uptake following ischemia-reperfusion in isolated rat hearts. Hearts were subjected to hypothermic cardioplegia at 26 degrees C for 80 minutes with and without carnitine 10 mmol/L added to the perfusate and cardioplegic solution [Groups I (n = 9) and II (n = 14), respectively]. Additionally, to study myocardial carnitine uptake, hearts were subjected to global ischemia at 20 degrees C [Group III (n = 6) and IV (n = 6)] and at 37 degrees C [Group V (n = 6) and VI (n = 6)] with and without carnitine 10 mmol/L added to the perfusate. All hearts received normothermic reperfusion, and Krebs-Henseleit solution was used as the perfusate in all groups. Postischemic aortic flow, expressed as the percentage of pre-ischemic flow, morphometric scores of myocardial mitochondria, and the myocardial concentration of adenosine triphosphate at the end of reperfusion were significantly higher in Group I than in Group II. In hearts treated with L-carnitine both at 20 degrees C and 37 degrees C the myocardial concentrations of carnitine fractions (free, short-acyl, and long-acyl) increased significantly compared to those in hearts without L-carnitine treatment. The myocardial concentration of free carnitine at the end of reperfusion was significantly higher in Group III than at pre-ischemia. These results suggest that exogenous L-carnitine is incorporated into cellular metabolism, even in hypothermic cardioplegia, improving cardiac function and preserving the myocardial adenosine triphosphate concentration.

Adenosine Triphosphate↗