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Biomedical subjects

F Yamamoto

Publications and source records attributed to F Yamamoto.

At least 55 records · Page 3Linked to original sources
PubMed1998

An effective method for improving hemostasis in aortic root replacement with a composite graft.

Hemostasis during aortic root replacement with a composite graft, consisting of a separate Dacron graft and a valve, was markedly improved by using a supra-annular aortic wall reinforcing suture (SAWR). Between February 1994 and January 1998, 14 consecutive patients (10 men and 4 women) underwent replacement of the aortic valve and ascending aorta with the SAWR technique. No intraoperative bleeding of the aortic proximal suture line or early death occurred in this group. No patient required reoperation for bleeding of anastomoses. Three of 10 patients who underwent elective operations were operated on successfully without blood transfusion. In addition, no clinical complications related to the SAWR technique were observed in the follow-up period. We conclude that the SAWR technique can be performed easily and may be an effective method for improving proximal hemostasis.

Aortic Dissection↗
PubMed1998

Artificial chordae for mitral valve reconstruction in children.

BACKGROUND: Congenital mitral regurgitation continues to present a challenge for cardiac surgeons because of the diversity of the anatomy of the congenitally malformed mitral valve. We undertook aggressive repair of the mitral valve with artificial chordae for reconstruction of the prolapsed anterior leaflet in some children. The short-term results are reported herein. METHODS: Three patients with isolated congenital mitral regurgitation underwent mitral valve repair with use of expanded polytetrafluoroethylene sutures as artificial chordae. RESULTS: There have been no late deaths and no valve-related complications. Serial follow-up echocardiographic examinations have not revealed any increase in the severity of mitral regurgitation with continuing patient growth up to 39 months after the operation. CONCLUSIONS: When combined with other conservative methods of mitral valve repair, chordal replacement with expanded polytetrafluoroethylene sutures in children undergoing mitral valve reconstruction produces good short-term results. We believe that it delays and possibly prevents the need for a mechanical prosthesis with its associated complications in this young patient population.

Cardiac Volume↗
PubMed1998

Improved success rate of the maze procedure in mitral valve disease by new criteria for patients' selection.

OBJECTIVE: We have carried out the maze procedure for atrial fibrillation (AF) as a combined operation with mitral valve surgery in a consecutive fashion until December 1994 (period 1). Therefore, the success rate in sinus rhythm conversion remained unsatisfactory. We have selected the patients according to arbitrarily decided new criteria since January 1995 (period 2), and examined the results prospectively. METHODS: Between May 1992 and February 1997, we carried out the maze procedure in 220 patients as a combined operation with mitral valve surgery. During period 2, we carried out the maze procedure in 63 cases who satisfied all the new criteria (voltage of f-wave in V1 lead > 0.1 mV, cardiothoracic ratio (CTR) < 70%, LA dimension < 70 mm), and 37 patients out of these criteria. Success was defined as sinus rhythm restoration without sick sinus syndrome. RESULTS: There were 4 hospital deaths (1.8%) and 4 late deaths (1.8%). Success rate was significantly (P = 0.0089) higher in period 2 (82%) than in period 1 (65%). Success rate was significantly higher in patients within criteria than out of criteria both in period 1, period 2, and total (77 versus 48%, P = 0.018; 90 versus 66%, P = 0.004, and 83 versus 55%, P = 0.0001). CONCLUSION: The maze procedure is highly reliable when combined with mitral valve surgery if patients are selected properly.

Adult↗
PubMed1998

Regulation by uniconazole-P and gibberellins of morphological and anatomical responses of Fraxinus mandshurica seedlings to gravity.

The present study deals with roles of gibberellins (GAs) in gravitropic responses of woody stems of horizontally-positioned, 2-year-old seedling of Fraxinus mandshurica Rupr. var. japonica Maxim. The application of uniconazole-P, an inhibitor of GAs biosynthesis, to stem nodes at various concentrations significantly inhibited not only righting the stems but also wood formation. The application of GAs (GA3 and GA4) in combination with uniconazole-P negated the inhibitory effect of the treatment of uniconazole-P alone. The GAs alone did not affect wood formation, however, both GAs increased wood formation on both the upper and lower sides of horizontal stems with an increase in the concentration of combined uniconazole-P. In all of the seedlings, tension wood was formed on the upper side of stems. The application of uniconazole-P alone at various concentrations did not inhibit the formation of tension wood fibres.

Dose-Response Relationship, Drug↗
PubMed1998

Effect of preischemic catecholamine treatment on ischemia-reperfusion injury of the myocardium: subtype, dose, and temperature dependency.

Preischemic adrenergic stimulation may affect postischemic cardiac function. Using an isolated working heart model, we investigated the effects of preischemic catecholamine treatment on postischemic recovery. Hearts from Wistar rats were perfused in working mode for 20 min, in Langendorff mode for 15 min, and again in working mode for 20 min (W2). Hearts were treated with isoproterenol (8.0 and 40.0 nmol/L), phenylephrine (0.06, 0.30, and 1.50 micromol/L), or epinephrine (16 and 80 nmol/L) during the W2 period and then arrested with St Thomas' Hospital cardioplegic solution (STH) and subjected to global ischemia (37 degrees C or 20 degrees C), followed by reperfusion. At 37 degrees C, isoproterenol had a beneficial effect at the lower dose but a harmful effect at the higher dose; phenylephrine and epinephrine had a harmful effect at all doses. At 20 degrees C, isoproterenol and epinephrine had a harmful effect at a high dose; phenylephrine had no harmful effect at any dose. In a separate study, the influence of calcium modulators (diltiazem and ryanodine, added in the STH) on the catecholamine effect was investigated. The harmful effect of preischemic treatment with isoproterenol (24.0 nmol/L) or phenylephrine (0.9 micromol/L) was abolished by the calcium modulators. Thus, preischemic beta-adrenergic or alpha + beta-adrenergic stimulation has a deleterious effect on postischemic recovery of the myocardium. The effect could be altered depending on the subtype and dose of catecholamine and the ischemic temperature. Intracellular calcium movement could be involved in the mechanism responsible for the harmful effect of preischemic catecholamine treatment.

Adrenergic beta-Agonists↗
PubMed1998

[Surgical treatment for prosthetic valve endocarditis].

From April 1993 to May 1997, 21 patients underwent surgical treatment for prosthetic valve endocarditis (PVE). There were 13 males and eight females aged from 46 to 79 years old (mean 62 years). There were four cases of early PVE (onset of PVE within 60 days from previous valve replacement), and 17 cases of late PVE (after 60 days). The predominant organisms were Staphylococcus epidermidis (eight cases), Staphylococcus aureus (two cases), MRSA (one case), streptococcal species (three cases), Candida (two cases), Pseudomonas cepacia (one case) and Enterococcus (one case). The predominant organisms were identified in 16 of 20 cases by preoperative blood culture, and in 11 of 20 cases by intraoperative tissue culture, and in 19 cases in all. There were four cases of preoperative cerebral complications, and three cases resurged. The hospital mortality rate was 24% (five patients). Reoperation was required in four patients for recurrence of PVE. Autopsy was performed in four of five patients. Intramyocardial abscess was detected in three patients. Earlier diagnosis and earlier surgical treatment could prevent emboli due to vegetations, which might cause catastrophic results, and could achieve better outcomes. Identification of the predominant organisms, especially from operative tissue cultures, is required.

Aged↗
PubMed1997

Transcription of human ABO histo-blood group genes is dependent upon binding of transcription factor CBF/NF-Y to minisatellite sequence.

We have studied the transcriptional regulatory mechanism of the human histo-blood group ABO genes, and identified DNA cis-elements and trans-activating protein that control the expression of these genes which are important in blood transfusion and organ transplantation. We introduced the 5'-upstream sequence of ABO genes into the promoterless reporter vector and characterized the promoter activity of deletion constructs using transient transfection assays with gastric cancer cell line KATO III cells. The sequence just upstream of the transcription start site (cap site), and an enhancer element, which is located further upstream (between -3899 and -3618 base pairs (bp) from the transcription initiation site) and contains 4 tandem copies of a 43-bp repeat unit, were shown in gastric cancer cells to be responsible for the transcriptional activity of the ABO genes. DNA binding studies have demonstrated that a transcription factor, CBF/NF-Y, bound to the 43-bp repeat unit in the minisatellite. Functional importance of these CBF/NF-Y-binding sites in enhancer activity was confirmed by transfection experiments using reporter plasmids with mutated binding sites. Thus, transcriptional regulation of the human ABO genes is dependent upon binding of CBF/NF-Y to the minisatellite.

ABO Blood-Group System↗
PubMed1997

Effects of protease inhibitors on postischemic recovery of the heart.

It is well known that activation of proteases in the lysosomes and cytosol is one of the mechanisms of ischemic injury. It might thus be beneficial to determine whether the addition of several clinically available protease inhibitors to a cardioplegic solution can improve its protective ability. Using an isolated working rat heart preparation, the effects of several protease inhibitors (serine protease inhibitors; nafamostat mesilate and gabexate mesilate, a thiol-protease inhibitor; NCO-700; and a urinary trypsin inhibitor, urinastatin) on the postischemic recovery of function and enzyme leakage were investigated in this study. These protease inhibitors were added to either the cardioplegic solution or reperfusion solution. The addition of each of the protease inhibitors, except urinastatin, to the cardioplegic solution improved the postischemic recovery of function and reduced enzyme leakage. The dose-response characteristics of these three protease inhibitors were bell shaped, and the optimal concentrations of nafamostat mesilate, gabexate mesilate, and NCO-700 were 5 microM, 100 microM, and 20 microM, respectively. In contrast to the results of the preischemic treatment study, the addition of any of the protease inhibitors to the perfusion medium during Langendorff reperfusion failed to improve the postischemic recovery of function and to reduce enzyme leakage. Surprisingly, the addition of NCO-700 to the reperfusion solution at a concentration of 5 microM or higher had rather harmful effects on both functional recovery and enzyme leakage. These findings suggest that serine and thiol proteases may play an important role in myocardial injury during ischemia, but not necessarily during reperfusion.

Animals↗
PubMed1997

Evolution of primate ABO blood group genes and their homologous genes.

There are three common alleles (A, B, and O) at the human ABO blood group locus. We compared nucleotide sequences of these alleles, and relatively large numbers of nucleotide differences were found among them. These differences correspond to the divergence time of at least a few million years, which is unusually large for a human allelic divergence under neutral evolution. We constructed phylogenetic networks of human and nonhuman primate ABO alleles, and at least three independent appearances of B alleles from the ancestral A form were observed. These results suggest that some kind of balancing selection may have been operating at the ABO locus. We also constructed phylogenetic trees of ABO and their evolutionarily related alpha-1,3-galactosyltransferase genes, and the divergence time between these two families was estimated to be roughly 400 MYA.

ABO Blood-Group System↗
PubMed1997

[The temperature dependency of the protective properties of the St. Thomas' Hospital cardioplegic solution, the University of Wisconsin solution, and Bretschneider buffered solution].

We studied three preservation solutions such as St. Thomas' hospital cardioplegic solution No. 2 (ST), the University of Wisconsin solution (UW) and Bretschneider's solution (BR) for protective properties, especially in terms of temperature dependence during the preservation. Rat hearts were studied and divided into three groups; ST. UW and BR. In each group, six hearts were carried out perfusion, cardioplegic infusion, ischemia and reperfusion for four different conditions. Using an isolated working rat heart model, the hearts were subjected to 5 minutes Langendorff perfusion followed by 20 minutes working perfusion. During this working period, cardiac functions such as aortic and coronary flow, aortic pressure, and heart rates were measured every 5 minutes. After working perfusion, 3 minutes of cardioplegic infusion was carried out either with UW, ST, and BR at 37, 20, 4, 1 degree C. The hearts were subjected to either 35 min at 37 degrees C, 120 min at 20 degrees C, 300 min at 4 degrees C, or 450 min at 1 degree C. The hearts were immersed in the same solution during ischemia. The hearts were reperfused at 37 degrees C, initially in the Langendorff mode for 15 min. Coronary effluent was collected for the measurement of CK leakage during reperfusion. The heart were then converted to the working mode for 20 minutes. During working reperfusion period, the variables of cardiac function were again measured and expressed as a percentage of their individual preischemic control values. Under conditions of 37 degrees C ischemia, % recovery of cardiac output (%CO) in ST group is 62.8 +/- 2.8%, although the hearts preserved with UW and BR were not recovered. Under conditions of 20 degrees C ischemia, %CO in UW, ST and BR were 46.8 +/- 2.7, 82.0 +/- 3.1 and 41.4 +/- 2.6%, respectively. Under conditions of 4 degrees C ischemia, %CO in UW, ST and BR were 66.2 +/- 8.0, 68.6 +/- 2.3 and 47.2 +/- 2.9%, respectively. Under conditions of 1 degrees C ischemia, %CO in UW, ST and BR were 70.6 +/- 3.3, 56.5 +/- 1.6 and 43.0 +/- 2.5%, respectively. In conclusions, ST revealed the best protective properties for the heart preservation between 37 degrees C and 20 degrees C ischemia. The properties of ST was similar to that of UW under conditions of 4 degrees C, although UW showed most excellent protective properties under conditions of 1 degrees C ischemia. These results suggested that, protective ability of preservation solution might be changed by the temperature during preservation period.

Adenosine↗
PubMed1996

Amino acid residue at codon 268 determines both activity and nucleotide-sugar donor substrate specificity of human histo-blood group A and B transferases. In vitro mutagenesis study.

Histo-blood group A transferase produces A antigens and transfers GalNAc to the acceptor substrate, H structures of glycolipids and glycoproteins. B transferase transfers galactose in place of GalNAc to the same acceptor substrate to synthesize B antigens. We have previously identified four amino acid substitutions between human A and B transferases. Out of these four, substitutions at the last two positions (codons 266 and 268) were found to be crucial for the different donor nucleotide-sugar specificities between A and B transferases as analyzed by gene transfer of chimeric A-B transferase genes. In the present study, we have in vitro mutagenized codon 268 of these two transferase cDNA expression constructs (glycine and alanine in A and B transferases, respectively) and produced substitution constructs with every possible amino acid residue at this position. We examined the activity and specificity of each construct by gene transfer followed by immunodetection of A and B antigens and in vitro enzymatic assay. Amino acid substitution constructs on the A transferase backbone with alanine, serine, and cysteine expressed enzymes with A and B transferase activities. Weak A activity was detected with histidine and phenylalanine constructs while weak B activity was detected with asparagine and threonine constructs. All the other amino acid substitutions at codon 268 on the A transferase backbone showed neither A nor B activity. The glycine construct on the B transferase backbone expressed both A and B transferase activities. Some substitution constructs on the B transferase backbone maintained B activity while some other substitutions abolished the activity. These results show that the side chain of the amino acid residue at 268 of the human A and B transferases is responsible for determining both activity and nucleotide-sugar donor substrate specificity and strongly suggest its direct involvement in the recognition of and binding to the sugar moiety of the nucleotide-sugars.

Amino Acids↗
PubMed1996

Positron-labeled antioxidant 6-deoxy-6-[18F]fluoro-L-ascorbic acid: increased uptake in transient global ischemic rat brain.

The in vivo uptake and distribution of 6-deoxy-6-[18F]fluoro-L-ascorbic acid (18F-DFA) were investigated in rat brains following postischemic reperfusion. Global cerebral ischemia was induced in male Wistar rats for 20 min by occlusion of four major arteries. Two time points were chosen for 18F-DFA injection to rats subjected to cerebral ischemia, at the start of recirculation and 5 days following recirculation. The rats were then killed at 2 h after tail-vein administration of 18F-DFA and tissue radioactivity concentration was determined. Increased uptake of radioactivity in particular brain regions, including the cerebral cortex, hypothalamus, and amygdala following injection of 18F-DFA, compared to the sham-operated control, was observed 5 days after reperfusion. Similar results were also obtained in in vitro experiments using brain slices. Abnormal in vivo accumulation of 45Ca, a marker of regional postischemic injury, was observed in these brain regions in tissue dissection experiments. Furthermore, metabolite analysis of nonradioactive DFA using 19F-NMR showed that DFA remained intact in the postischemic reperfusion brain. The present results indicate that 18F-DFA increasingly accumulates in damaged regions of postischemic reperfusion brain.

Animals↗
PubMed1996

Unifocalization for pulmonary atresia with ventricular septal defect and major aortopulmonary collateral arteries.

To extend the indications for corrective operation in patients with pulmonary atresia, ventricular septal defect, and major aortopulmonary collateral arteries, surgical procedures were done to unify the blood sources for pulmonary perfusion. Since December 1985, 50 patients have undergone unifocalization at ages from 2 months to 26 years with a mean of 6 +/- 7 years. In total, 84 staged unifocalization procedures and 5 other palliative procedures were done in 49 patients. These included several operative procedures: simple ligation of major aortopulmonary collateral arteries in 8; pulmonary angioplasty in 29 including reconstruction of the pulmonary arterial tree by direct anastomosis or interposition between the central pulmonary arteries and the intrapulmonary arteries; construction of artificial central pulmonary arteries with use of a xenograft pericardial tube graft in 36 with no native central pulmonary arteries detected; and construction of supplemental central pulmonary arteries also with use of a pericardial tube graft in 10. The pericardial tube graft, if used, was anastomosed to the intrapulmonary arteries on one end and connected to a prosthetic tube on the other end so as to perfuse the reconstructed pulmonary arteries. The anastomosis was made inside the lung through the divided interlobar fissure. Five patients died after operation among those undergoing these 89 preparative operative procedures. Deaths were related either to bleeding caused by anticoagulation therapy administered to prevent thrombosis within the xenograft pericardial tube graft used or to progressive congestive heart failure as a result of an excessive amount of pulmonary blood flow. Twenty-six patients have undergone intracardiac repair after previous unifocalization. In 16 patients the artificial central pulmonary arteries surgically constructed were connected to each other and then an external conduit was placed. In another patient, intracardiac repair and unifocalization could be concomitantly achieved via a median sternotomy. The right ventricle to left ventricle systolic pressure ratio immediately after intracardiac repair in 27 patients ranged from 0.24 to 0.91 with a mean of 0.54 +/- 0.17. One patient (4%) died shortly after intracardiac repair because of thrombosis within the pulmonary arteries. Postoperative catheterization showed that pulmonary vascular resistance was correlated significantly with the number of pulmonary vascular segments functioning rather than with the condition of the central pulmonary arteries. We conclude that surgical unifocalization is a feasible procedure before subsequent intracardiac repair, even in patients with critically hypoplastic or absent central pulmonary arteries.

Adolescent↗
PubMed1996

Transient reperfusion with acidic solution affects postischemic functional recovery: studies in the isolated working rat heart.

This isolated working rat heart study was designed to investigate the effect of duration of reperfusion and degree of acidity of the reperfusate on myocardial protection. The experimental time course was as follows: 20 minutes of perfusion with the heart working, 3 minutes of infusion with the St. Thomas' Hospital cardioplegic solution followed by global ischemia for 33 minutes at 37 degrees C, and 20 minutes of Langendorff reperfusion followed by 20 minutes of working perfusion. During the initial 3 minutes of Langendorff reperfusion, the pH of the reperfusate was changed to 5.6, 6.8, and 7.5 by addition of sodium hydroxide into Krebs-Henseleit nonbicarbonate HEPES buffer. A respiratory acidic reperfusate was used for the initial 0.5, 1, 2, 3, 5, and 15 minutes during reperfusion. The results were as follows: (1) Reperfusion with a mildly acidic solution (i.e., pH 6.8) yielded better recovery than reperfusion with solutions having pH levels of 5.8 or 7.5. (2) Reperfusion for less than 3 minutes with a reperfusate having a pH level of 6.8 provided better recovery, although reperfusion for longer than 3 minutes exacerbated reperfusion injury. In conclusion, the effects of reperfusion with acidic solution were influenced by degree and duration with biphasic response characteristics.

Analysis of Variance↗
PubMed1996

Results of unifocalization for pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries: patency of pulmonary vascular segments.

Unifocalization, a surgical technique to unifocalize the pulmonary blood supply in patients with pulmonary atresia, ventricular septal defect and major aortopulmonary collateral arteries, is a useful preparative operation to extend the indication for corrective surgery. The preoperative and postoperative pulmonary angiograms of 51 patients (aged 3 months-26 years at first unifocalization, 29 males, 22 females), who underwent a total of 96 unifocalizations from December 1985 to July 1994, were studied to assess the effectiveness of each procedure of unifocalization. The procedures of unifocalization were ligation (9), angioplasty (6), direct anastomosis (25), bridging (6), additional central pulmonary artery creation (9), central pulmonary artery creation (36) and thrombectomy (5). Altogether 125 anastomoses were made, and the patency of 101 (80.2%) anastomoses was confirmed, 24 (19.2%) were shown to be occluded. The patency rate of the anastomoses between xenograft rolls and intrapulmonary arteries was 79.5% (70/88), while that between native central pulmonary arteries and intrapulmonary arteries was 83.8% (31/37; N. S.). The patency rate of the anastomoses involving intrahilar arteries was 88.0% (44/50), while that for the group involving extrahilar arteries only was 71.9% (46/64; P < 0.05). It is concluded that 1) unifocalization with the reconstruction of central pulmonary arteries using a pericardial roll is a useful method for patients with absent or hypoplastic central pulmonary arteries, 2) it is preferable to divide the fissures of lung in anastomosing pulmonary arteries of arborization abnormalities.

Adolescent↗
PubMed1996

Temperature-dependent cardioprotection of exogenous substrates in long-term heart preservation with continuous perfusion: twenty-four-hour preservation of isolated rat heart with St. Thomas' Hospital solution containing glucose, insulin, and aspartate.

BACKGROUND AND METHODS: Using an isolated working rat heart model, we determined the effects of glucose, insulin, and aspartate on recovery of cardiac function when used as components of preservation solution at different temperatures. After measurement of baseline cardiac function, hearts (n = 6 per group) were perfused with oxygenated St. Thomas' Hospital solution containing (1) vehicle, glucose (9 mmol/L) or aspartate (20 mmol/L) for 12 hours at either 20 degrees or 4 degrees C; (2) glucose or glucose + insulin (10 U/L) at 20 degrees C for 20 hours; and (3) glucose + insulin at 20 degrees C or glucose + insulin + aspartate at either 20 degrees or 4 degrees C for 24 hours. Cardiac function was measured after preservation and expressed as a percentage of baseline values. RESULTS: At 20 degrees C, both glucose and aspartate increased recovery of cardiac output (vehicle, 57.7% +/- 3.8%; glucose, 76.5% +/- 2.4% [p < 0.05 versus vehicle]; aspartate, 79.9% +/- 1.4% [p < 0.05 versus vehicle]). At 4 degrees C, glucose decreased recovery of cardiac output, whereas aspartate did not change the value (vehicle, 74.4% +/- 2.2%; glucose, 61.4% +/- 2.8% [p < 0.05 versus vehicle]; aspartate, 80.5% +/- 1.7%). The addition of insulin to glucose increased recovery of cardiac output (glucose, 24.6% +/- 4.0%; insulin + glucose, 69.2% +/- 2.0%: p < 0.05). The combined use of these three agents showed an additive effect in improvement of recovery of cardiac output at 20 degrees C (glucose + insulin, 64.2% +/- 2.2%; glucose + insulin + aspartate, 76.0% +/- 1.1%; p < 0.05), but the recovery at 4 degrees C (63.1% +/- 1.8%) was significantly lower than at 20 degrees C. CONCLUSIONS: These results suggest that glucose and aspartate afford differential cardioprotective effects depending on the temperature of the preservation solution and that combined use of glucose, insulin, and aspartate at the optimal temperature may extend graft preservation time.

Animals↗
PubMed1996

[The effect of continuous perfusion with St. Thomas' Hospital cardioplegic solution containing glucose, insulin and L-aspartate on functional recovery after myocardial preservation in the rat].

UNLABELLED: The aim of this study was to determine the effect of the continuous perfusion with St. Thomas' Hospital cardioplegic solution (ST solution) containing glucose, insulin and L-aspartate upon post-preservation recovery of cardiac function in the isolated rat heart. METHODS: Hearts from Wistar male rats were perfused with Krebs-Henseleit bicarbonate buffer (KHBB) solution and cardiac function was measured using an isolated working heart preparation. Hearts were then preserved by continuous perfusion, (1) with ST solution or ST solution containing L-aspartate (20 mmol/L9 at 20 degrees C and 4 degrees C for 12 hours, (2) with ST solution containing L-aspartate at 4 degrees C for 24 hours, (3) with ST solution containing glucose (9 mmol/L) and insulin (10 U/L solution) or ST solution containing glucose, insulin and L-aspartate at 20 degrees C for 24 hours. This was followed by 15 minutes of Langendorff perfusion and 20 minutes of working perfusion with KHBB solution. During the working perfusion in the post-preservation period, cardiac function was remeasured. RESULTS: (1) At 20 degrees C, percent recovery of cardiac output (%CO) was 57.7 +/- 3.8% and 79.9 +/- 1.4*% in the L-aspartate-free group and the L-aspartate-containing group, respectively (*p < 0.05). At 4 degrees C, %CO was 74.4 +/- 2.2% and 80.5 +/- 1.7% in the L-aspartate-free group and the L-aspartate-containing group, respectively (NS). (2) %CO in L-aspartate-containing group at 4 degrees C decreased to 46.8 +/- 2.4% when preservation time was extended to 24-hours from 12 hours. (3) On the other hands, the addition of L-aspartate to the ST solution containing glucose and insulin resulted in an additive protection and %CO was 76.0 +/- 1.1% even after 24 hour preservation at 20 degrees C. CONCLUSIONS: Our results indicate that L-aspartate as an additive to perfusion medium might be beneficial for myocardial preservation, and that at 20 degrees C, the addition of L-aspartate to the ST solution containing glucose and insulin could improve the post-preservation recovery after the 24-hour preservation.

Animals↗