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Biomedical subjects

M Sunamori

Publications and source records attributed to M Sunamori.

At least 73 records · Page 4Linked to original sources
PubMed1994

Successful cardiac presrevation for 12 hours using nondepolarizing cold cardioplegia. A canine model.

Isolated canine hearts were preserved for 12 h at 5 degrees C followed by normothermic reperfusion for 2 h. Dogs were divided into two groups: group 1 (n = 7) received a nondepolarizing preservation solution in multidose, and group 2 (n = 6) received single-flushed University of Wisconsin (UW) solution, both administered in multidose fashion. At the end of reperfusion, the myocardial adenosine triphosphate concentration and left ventricular systolic and diastolic function were preserved better in groupl than in group 2. Myocardial mitochondrial ultrastructural integrity was identical in the two groups. These results suggested that in a 12-h heart preservation, nondepolarizing solution administered in multidose fashion protects the myocardium from the deleterious effects of hypothermia and cardioplegia better than UW solution.

Adenine Nucleotides↗
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

[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

Left ventricular diastolic function of the reperfused postischemic donor heart.

This study examined the pathophysiological relationship between left ventricular diastolic function and myocardial biochemical changes during reperfusion following hypothermic cardioplegic preservation of the donor heart. Isolated canine hearts (n = 47) were preserved for 6 h at 5 degrees C, followed by normothermic reperfusion for 2 h. Regression analysis demonstrated a highly significant correlation between: Left ventricular maximum -dp/dt and the left ventricular end-diastolic pressure (r = -0.56, P = 0.001); myocardial concentrations of adenosine triphosphate (ATP) and Ca2+ (r = -0.59, P = 0.0001); maximum -dp/dt and myocardial concentrations of: (1) ATP, (2) Ca2+, and (3) total adenine nucleotide with left ventricular volume loading (r = -0.53, P = 0.003; r = 0.51, P = 0.002; and r = 0.52, P = 0.002, respectively); and left ventricular end-diastolic pressure and myocardial Ca2+ (r = 0.66, P = 0.0001). These results suggest that left ventricular relaxation, as assessed by maximum -dp/dt, has a negative correlation with left ventricular stiffness, as determined by the end-diastolic pressure in preserved donor hearts. Furthermore, increased myocardial Ca2+ concentrations reflect exhaustion of myocardial ATP. Thus, the myocardial Ca2+ concentration correlates directly with wall stiffness and inversely with ventricular relaxation, while ATP concentration correlates directly with ventricular relaxation.

Adenosine Triphosphate↗
PubMed1993

Comparison of intermittent injection of nondepolarizing solution with a single flush of UW solution for donor heart preservation.

Isolated canine hearts were preserved for 6 h at 5 degrees C followed by normothermic reperfusion for 2 h. The dogs were divided into two groups of nine hearts each; group 1 received a nondepolarizing preservation solution in multidose, and group 2 received a single flush of University of Wisconsin (UW) solution. Serum MB-CK and mitochondrial aspartate aminotransferase (m-AAT) concentrations and calcium overload during reperfusion were lower in group 1 than in group 2. At the end of reperfusion, myocardial ATP and total adenine nucleotide concentrations were higher and mitochondrial morphology appeared more intact in group 1 than in group 2. Left ventricular diastolic function was preserved better in group 1 than in group 2. These results suggest that in 6-h heart preservation, a nondepolarizing solution applied in multidose fashion protects the myocardium from the deleterious effects of hypothermia and cardioplegia better than a single flush of UW solution.

Adenosine↗
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

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↗
PubMed1992

The significant role of membrane stabilization in hypothermic cardioplegic cardiac preservation in a canine experimental model.

Isolated mongrel hearts were preserved for 6 h at 5 degrees C followed by normothermic reperfusion for 2 h. The dogs were divided into three groups; K+-cardioplegic solution alone, group C, n = 7; K+-cardioplegic solution with lidocaine 200 mg/l, group L, n = 7; and K+-cardioplegic solution with betamethasone 250 mg/l and lidocaine 200 mg/l, group B + L, n = 7. Ventricular fibrillation occurred early during reperfusion in all dogs in group C, in one of seven in group L, and in two of seven dogs in group B + L. The serum MB fraction of creatinine kinase (MB-CK), mitochondrial aspartate aminotransferase (m-AAT) and calcium overload were suppressed to a greater extent in both groups L and B + L during reperfusion compared to group C. Myocardial ATP, total adenine nucleotide, and creatine phosphate did not differ between the three groups at the end of reperfusion. Myocardial ADP and AMP declined significantly during reperfusion in group C, however, they remained unchanged in group B + L and increased in group L which showed significantly higher levels compared to group C. Left ventricular functional recovery during reperfusion was consistently better in both group L and B + L compared to group C. These results suggested that membrane stabilization prevents myocardial damage from hypothermia and cardioplegia and provides better myocardial viability and functional recovery in donor heart preservation.

Animals↗
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

Clinical experience of coenzyme Q10 to enhance intraoperative myocardial protection in coronary artery revascularization.

Seventy-eight patients undergoing coronary artery bypass grafting (CABG) were compared retrospectively to evaluate whether pretreatment with coenzyme Q10 (CoQ) is effective in preventing left ventricular depression in early reperfusion following CABG. CoQ (5 mg/kg, intravenously) was given to 60 patients, 2 hours prior to the onset of cardiopulmonary bypass (CPB). CABG was performed using saphenous vein under CPB associated with cold cardioplegia in the standard fashion. Heart rate, mean arterial pressure, and cardiac index showed no significant difference between the CoQ and control groups. However, left ventricular stroke work index was significantly elevated at 6 and 10 hours of reperfusion following CABG in the CoQ-treated group compared with the controls. Serum MB-CK was lower at 0 and 6 hours of reperfusion in the CoQ group compared with the controls. These results suggest that pretreatment with intravenous CoQ is effective in preventing left ventricular depression in early reperfusion and in minimizing myocardial cellular injury during CABG followed by reperfusion.

Coenzymes↗
PubMed1991

Effect of aprotinin to improve myocardial viability in myocardial preservation followed by reperfusion.

Isolated canine hearts were preserved at 4 degrees C with multi-dose cardioplegic solution every hour for 6 hours. Reperfusion was observed for 2 hours under cross-circulation without cardiotonic drugs. The aprotinin group (n = 8), which received cardioplegic solution with added aprotinin (150 KIU/mL), was compared with the control group (n = 6). The increase in tissue adenosine triphosphate and total adenine nucleotide content during reperfusion was significant in the aprotinin group; there was no change in the control group, and the levels at the end of reperfusion tended to be higher in the aprotinin group than in the control group. Tissue adenosine diphosphate levels remained unchanged in both groups. Tissue adenosine monophosphate levels declined during reperfusion in both groups and were slightly lower in the control group. Tissue levels of cyclic adenosine monophosphate remained unchanged in the aprotinin group whereas they increased during ischemia and declined significantly during reperfusion in the control group. Tissue levels of cyclic guanosine monophosphate declined during reperfusion in both groups without difference. Creatine phosphate levels recovered in both groups without difference. Serum cyclic guanosine monophosphate concentration tended to be lower in the aprotinin group than in the control group. Serum creatine kinase-MB level increased slightly during reperfusion in both groups without difference. N-acetyl-beta-D-glucosaminidase levels were significantly suppressed during reperfusion in the aprotinin group as compared with the control group. These results suggest that aprotinin is effective in preserving adenine nucleotide and adenosine triphosphate levels and in stabilizing tissue cyclic adenosine monophosphate levels in prolonged hypothermic cardioplegic preservation followed by reperfusion.

Acetylglucosaminidase↗
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↗