Inhaled nitric oxide for the postoperative management of Fontan-type operations.
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Administration, Inhalation↗
Biomedical subjects
F Yamamoto
Publications and source records attributed to F Yamamoto.
Effects of intravenous superoxide dismutase and catalase on electroretinogram in the cat postischemic retina.
We examined the effects of the antioxidant enzymes, 10,000 U/kg of superoxide dismutase (SOD) and 50,000 U/kg of catalase (CAT) on cat electroretinograms during the reperfusion after retinal ischemia. The intravenous administrations of SOD and CAT promoted the recovery of the c-wave after 30 min of ischemia but not the b-wave. At 5 min after onset of reperfusion, SOD- and CAT-treated eyes showed 90 and 110% recovery of the c-wave amplitude respectively, against 50% recovery in the untreated eyes. These results suggested that the oxygen-derived free radicals affected the retinal pigment epithelium at the early period of reperfusion.
Animals↗
[Myocardial preservation by continuous perfusion of Krebs-Henseleit solution--the temperature dependency of the optimal perfusion pressure].
The aim of this study was to determine the temperature dependency of the optimal pressure in myocardial preservation by continuous perfusion with Krebs-Henseleit bicarbonate buffer (KHBB) solution. Hearts from Wistar male rats were perfused with KHBB solution and cardiac function (aortic flow) was measured using an isolated working rat heart preparation. In the preliminary experiment, hearts were then preserved using Langendorff perfusion with KHBB solution of 37, 20 or 4 degrees C for 2 hours at a perfusion pressure of 100 cmH2O. This was followed by 15 min of Langendorff perfusion (37 degrees C, 100 cmH2O) and 20 min working perfusion. The 37 degrees C group and 20 degrees C group exhibited better functional recoveries of aortic flow (%AF) in the post-preservation period compared to the 4 degrees C group. In the test experiment, hearts were preserved using Langendorff perfusion for 4 hours at 37 degrees C or for 8 hours at 20 degrees C at various perfusion pressures. At 37 degrees C, %AF after 4 hours of the preservation were 64.7 +/- 2.6, 69.0 +/- 3.2, 81.9 +/- 3.1, 94.7 +/- 3.3 and 63.5 +/- 4.0% (p < 0.05 vs the 100 cmH2O group) at the perfusion pressure of 100, 60, 20, 15 and 10 cmH2O, respectively. %AF after 8 hours of the preservation at 15 cmH2O was 56.3 +/- 2.5%. At 20 degrees C, %AF after 8 hours of the preservatin was 78.9 +/- 3.3, 81.9 +/- 2.3, 67.4 +/- 1.9 and 65.9 +/- 2.2% (p < 0.05 vs the 60 cmH2O group) at the perfusion pressure of 60, 30, 10 and 15 cmH2O, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Analysis of electroretinogram during systemic hypercapnia with intraretinal K(+)-microelectrodes in cats.
PURPOSE: Systemic hypercapnia alters the intraretinal pH and metabolism and profoundly affects the vitreal electroretinogram (ERG). Using intraretinal K(+)-selective microelectrodes (ISMs), the authors examined the effects of systemic hypercapnia on ERG in the intact cat eye in vivo. METHODS: Double-barreled K(+)-ISMs were used to record intraretinal, light-evoked [K+]o decrease, intraretinal ERG, vitreal ERG, and standing potential (SP) in the dark-adapted retina. Hypercapnia was induced by adding CO2 to the inhaled mixture of gas (without significant hypoxia). RESULTS: The standing potential was elevated, and the vitreal ERG c-wave increased in amplitude whereas the b-wave decreased during hypercapnia. Intraretinal recordings showed that the amplitudes of slow PIII and the transepithelial (TEP) c-wave decreased. The slow PIII decreased more than the TEP c-wave. The light-evoked [K+]o decrease also was reduced, but no change was noted in the subretinal [K+]o. CONCLUSION: The neural retina was more sensitive than the retinal pigment epithelium to the intraretinal acidification caused by systemic hypercapnia. However, the change in the SP and b-wave suggested complicated effects other than acidosis.
Animals↗
[Myocardial protection and the sarcoplasmic reticulum--the effect of ryanodine treatment prior to cardioplegic arrest on post-ischemic functional recovery].
Sarcoplasmic reticular (SR) calcium depletion may contribute to the myocardial protection against ischemia and reperfusion-induced injury. We have, therefore, investigated the effect of ryanodine-induced SR calcium depletion on the myocardial protection when given during Langendorff perfusion before ischemia in the isolated working rat heart. Hearts (n = 6/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with bicarbonate buffer (the first working perfusion), and then aerobically (37 degrees C) perfused with bicarbonate buffer containing 0, 1.75 or 7.00 nmol/L of ryanodine (a Langendorff perfusion). Hearts were then aerobically (37 degrees C) perfused (20 min) with ryanodine-free bicarbonate buffer (the second working perfusion). This was followed by a 3 min infusion of St. Thomas' Hospital cardioplegic solution, and then subjected to 38 min of normothermic (37 degrees C) global ischemia and 35 min of reperfusion (15 min Langendorff, 20 min working). After the ryanodine treatment, the percent reduction in aortic flow was significantly greater in the 7.00 nmol/L ryanodine group than in the control group. The post-ischemic recoveries of aortic flow were 39.1 +/- 3.3, 32.8 +/- 5.3 and 37.3 +/- 4.4% in the 0, 1.75 and 7.00 nmol/L ryanodine groups, respectively. There was no difference in the creatine kinase leakage during Langendorff reperfusion between the ryanodine-treated groups and the control group. Thus, ryanodine decreased the cardiac function after the ryanodine treatment, indicating a reduction in SR calcium content. Ryanodine, however, failed to improve the post-ischemic functional recoveries.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
[Successful aortic root replacement with pulmonary autograft in two infants].
Two infants with congenital aortic valve stenosis underwent successful aortic root replacement with pulmonary autograft. One of the patients was 9 months and weighted 4.2 kg, and the other was 10 weeks weighing 4.6 kg. The former had undergone balloon valvotomy with a resultant severe aortic regurgitation. Operative method was basically similar to that taught by Ross. In terms of the right ventricular outflow reconstruction, however, left atrial appendage was utilized as the posterior wall while equine pericardial monocusp patch formed the anterior wall in the former patient. In the latter, morphology of the left atrial appendage was not suitable for the same kind of reconstruction, and nonvalved equine pericardial tube was used. Both of the patients eventually gained satisfactory circulatory condition. Advantages of aortic root replacement with pulmonary autograft are good competence without residual stenosis, avoidance of anticoagulation, and the high potential of future growth. So this operation is especially indicated for neonates and infants with left ventricular outflow obstruction.
Aorta↗
Intraretinal study of cat electroretinogram during retinal ischemia-reperfusion with extracellular K+ concentration microelectrodes.
PURPOSE: Intraretinal electroretinograms (ERG) during retinal ischemia-reperfusion were analyzed to clarify which cells are affected in the cat dark-adapted eye. METHODS: Ischemia was induced by raising the intraocular pressure above arterial systolic pressure in vivo. Double-barreled microelectrodes were used to record the intraretinal ERGs and the light-evoked [K+]o decrease in the subretinal space. Vitreal ERGs, the standing potential and the transepithelial resistance were also recorded. RESULTS: After 10 minutes of ischemia, vitreal ERG b- and c-waves had recovered fully in 2 hours, and after 30 minutes of ischemia, recovered approximately 85% and 77% of their control amplitudes in 4 hours, respectively. At the early period of reperfusion after 10 minutes of ischemia we observed the supernormal c-wave (124% of its control amplitude, n = 10) with an elevated standing potential. The transepithelial potential (TEP) c-wave increased without changes of slow PIII and transepithelial resistance when the supernormal amplitudes occurred. The light-evoked [K+]o decrease in the subretinal space (90% retinal depth) in the area centralis recovered to about 90% of the control amplitude in 2 hours, and after 30 minutes of ischemia recovered to about 70% of the control amplitudes in 4 hours. The recovery courses of the slow PIII and TEP c-wave were almost the same as that of the light-evoked [K+]o decrease. CONCLUSIONS: The temporary supernormal amplitude of the ERG c-wave was originated from the retinal pigment epithelium (RPE) during the early period of reperfusion after 10 minutes of ischemia. The photoreceptors, Muller cell and RPE are responsible for the changes in the light-evoked [K+]o decrease, a slow PIII and TEP c-wave, respectively. Intraretinal recordings suggested that after ischemia of 10 to 30 minutes duration, the responses of photoreceptors, Muller cells and the RPE recovered with a similar time course. These findings suggest that in all cases, primarily photoreceptors were damaged.
Animals↗
DMSO preparation as a direct solubilizer of calcium bilirubinate stones.
Despite considerable progress in operative techniques, biliary surgeons continue to encounter difficulties when treating patients with intrahepatic gallstones. We have experienced a significant number of patients in whom complete stone removal was impossible during an operation due to the anatomical complexity of intrahepatic bile ducts, and the variety in the size and hardness of the stones. Under such circumstances, the application of a direct solubilizer capable of dissolving intrahepatic calcium bilirubinate stones, might be a possible alternative. Up to now, however, only calcium chelating agents have been used for removing calcium from calcium bilirubinate stones, and they are not always effective. As a promising solution to this problem, we have now developed a direct solubilize for bilirubin complexes--a dimethyl sulfoxide (DMSO) preparation. DMSO is a well-known bipolar nonprotonic solvent. We prepared solutions of DMSO and performed toxicological studies by administering this preparation to rats and dogs. Biochemical indices of liver and renal function remained unchanged after 7-28 days of DMSO administration. Nor were there any histological changes in the DMSO-treated animals on systemic survey of various organs. On comparing the in vitro capability for solubilizing calcium bilirubinate stones, the DMSO preparation was consistently superior to a calcium chelating agent alone. The combination of a chelating agent with DMSO had the highest solubilizing capacity.
Animals↗
[Sarcoplasmic reticular calcium release and myocardial protection--effect of ryanodine on myocardial ischemia and reperfusion-induced injury].
Calcium release from sarcoplasmic reticulum (SR) may contribute to the intracellular calcium overload observed during myocardial ischemia and reperfusion. We have therefore investigated the ability of ryanodine to enhance myocardial protection when given before ischemia or during reperfusion in the isolated working rat heart. Hearts (n = 6-9/group) from male Wistar rats were aerobically (37 degrees C) perfused (20 min) with bicarbonate buffer (Ca2+ = 2.4 mM). In the first series of studies, this was followed by a 3 min infusion of St Thomas' Hospital cardioplegic solution containing various concentrations of ryanodine. Hearts were then subjected to 38 min of normothermic (37 degrees C) global ischemia and 35 min of reperfusion (15 min Langendorff, 20 min working). The recoveries of aortic flow (%AF) were 50.3 +/- 2.5% in the ryanodine free controls versus 55.2 +/- 5.8, 72.0 +/- 1.3 (p < 0.05), 61.0 +/- 4.3, 51.8 +/- 5.1 and 32.1 +/- 5.0 (p < 0.05)% in the 0.88, 1.75, 2.13, 2.50 and 10.00 nM ryanodine groups, respectively. Creatine kinase (CK) leakage during Langendorff reperfusion was reduced in the 1.75 nM group but was similar to control in all other groups. In the second series of studies, 3 min of cardioplegia without ryanodine and 38 min of ischemia (37 degrees C) were followed by 15 min of Langendorff reperfusion with 0, 0.09, 0.18, 0.88 or 1.75 nM ryanodine, %AF was 59.3 +/- 3.3%, 54.7 +/- 3.3, 53.8 +/- 3.5, 38.4 +/- 8.9 (p < 0.05) and 33.3 +/- 5.8 (p < 0.05)% in the 0, 0.09, 0.18, 0.88 and 1.75 nM ryanodine groups, respectively. CK leakage tended to increase dose-dependently.(ABSTRACT TRUNCATED AT 250 WORDS)
Animals↗
Double switch operation in cardiac anomalies with atrioventricular and ventriculoarterial discordance.
Since June 1987, 10 of 19 consecutive patients with atrioventricular and ventriculoarterial discordance (average age 4 +/- 2 years) had undergone a double switch operation with the morphologically left ventricle used as a systemic ventricle. There were two combinations of procedures. Atrial switch combined with arterial switch was used in two patients who had a normal pulmonary valve. Atrial switch combined with ventriculoarterial switch by Rastelli's procedure was used in eight patients with pulmonary stenosis or atresia and a large ventricular septal defect. One early death and two late deaths have occurred in a postoperative follow-up period of up to 4 years. Subsequent problems were mainly related to the results of atrial switch procedures in patients who had a small atrium because of low pulmonary flow, especially in patients with apicocaval juxtaposition. Our experience suggested that the double switch operation would open a new era of definitive surgical treatment in half of the patients with atrioventricular and ventriculoarterial discordance.
Aorta↗
[Inhaled nitric oxide after Fontan type operation].
The indication of Fontan type operation has been extending, but some cases on the boundary of the indication resulted in low cardiac output syndrome (LOS) postoperatively. Recently the inhalation of nitric oxide (NO) has been revealed to produce selective pulmonary vasodilatation, and it has come to be applied in the clinical setting. We experienced a case of 6-year-old boy with complex cardiac anomaly in whom the inhalation of nitric oxide was remarkably effective for the LOS caused by increased pulmonary vascular resistance after Fontan type operation. In the case various conventional treatments failed to improve his LOS during the weaning from a respirator on the second postoperative day. After the initiation of the inhalation of nitric oxide at a concentration of 6ppm, a rapid decreasing of pulmonary artery pressure concomitant with an improvement of hemodynamics were obtained. We concluded that the inhalation of nitric oxide is an effective strategy for the increased pulmonary resistance after Fontan type operation.
Administration, Inhalation↗
Formation, inhibition of formation, and repair of oxidative 8-hydroxyguanine DNA damage.
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Base Composition↗
MR imaging of traumatic hepatic laceration: evaluation and course of healing after surgery.
Six patients with hepatic laceration underwent magnetic resonance imaging (MRI) at 0.5T. Acute hepatic laceration was slightly hypointense on T1-weighted spin-echo (SE) image, and hyperintense on T2- and proton-weighted SE images. Subacute laceration was heterogeneously intense on T1-weighted image and hyperintense on T2- and proton-weighted images. Consistent changes in signal intensity of postoperative hepatic laceration were observed. On T1-weighted image, the signal intensity at first increased and then decreased from periphery to the center. On the T2- and proton-weighted images, the laceration was uniformly hyperintense relative to the liver prior to the appearance and growth of a hypointense ring at its periphery. The appearance of the above changes in signal intensity was also observed in postoperative recurrent hemorrhage. The postoperative biloma had none of the above changes in signal intensity. Our cases show that MRI is effective in the evaluation of hepatic laceration and in the assessment of the course of healing after operation.
Adolescent↗
Increased lung injury in pulmonary hypertensive patients during open heart operations.
To investigate lung injury in adult open heart operations during extracorporeal circulation, we measured plasma chemiluminescence levels. Nineteen patients were divided into two groups depending on preoperative pulmonary artery pressure: a pulmonary hypertension group (n = 11) and a control group (n = 8). Plasma samples were taken simultaneously from arterial and central venous lines at six different points during and early after operation. Arteriovenous difference of chemiluminescence (counts/10 seconds) increased significantly only in the pulmonary hypertension group (from -19.1 +/- 8.3 at the end of cross-clamping to 23.7 +/- 12.4 at the end of bypass; p < 0.01). There was a positive correlation between peak values of arterial plasma chemiluminescence and postoperative respiratory index in the pulmonary hypertension group (p < 0.05). In addition, during the first 12 hours postoperatively, arteriovenous difference of chemiluminescence in the pulmonary hypertension group changed significantly from negative to positive values (p < 0.05). These data suggest that free radical activity (detected by chemiluminescence) was deeply involved in lung injury during and also early after open heart operations, especially in pulmonary hypertensive patients.
Adult↗
Cardiopulmonary bypass and cellular immunity: changes in lymphocyte subsets and natural killer cell activity.
To investigate whether cell-mediated immunity responses are suppressed or activated by the effect of cardiopulmonary bypass (CPB), we studied peripheral blood lymphocyte subsets and antibody-dependent cell-mediated cytotoxicity in 52 adult patients who had undergone open heart operations. Lymphocyte function also was studied with regard to mixed lymphocyte reaction, which indicates the amount of DNA synthesis of lymphocytes, and natural killer (NK) cytotoxicity, which represents the killing activity of NK cells on the tumor cells (K-562), in 11 patients. The total T lymphocyte (OKT3+ and OKT11+) number showed no significant change during CPB. Suppressor/cytotoxic T cell (OKT8+) and NK cell (Leu7+ and Leu11+) numbers were found to be remarkably increased. However, helper/inducer T cell (OKT4+) and B cell (Leu12+) numbers were decreased during CPB. Antibody-dependent cell-mediated cytotoxicity was elevated during CPB. All of these changes were almost returned to the preoperative levels by the seventh day after operation. Mixed lymphocyte reaction and NK cytotoxicity were also activated during CPB. The results show that heart operations in which cardiopulmonary bypass is used are associated with activation of cytotoxic cell-mediated immunity.
Antibody-Dependent Cell Cytotoxicity↗
Elevated level of 8-hydroxydeoxyguanosine in DNA of liver, kidneys, and brain of Long-Evans Cinnamon rats.
Long-Evans Cinnamon (LEC) rats, a mutant strain originating from Long-Evans rats, spontaneously develop hereditary hepatitis followed by hepatocellular carcinoma. The hepatic disorder in LEC rats is associated with their abnormal copper metabolism; metal-catalyzed reactions often give rise to oxygen radicals, which may be related to the carcinogenesis. By means of high-pressure liquid chromatography with electrochemical detection, cellular DNA damage caused by oxygen radicals can be assessed in terms of the amount of 8-hydroxydeoxyguanosine (oh8dG). We assayed the amount of oh8dG in DNA of liver, kidneys, and brain of LEC and Long-Evans Agouti (LEA) control rats in seven groups (n = 3 to 6) aged from 5 weeks to 24 months. Control rats, a healthy sibling line, were age-matched. The amount of oh8dG was correlated with the severity of the age-related clinical symptoms in LEC rats. The amount was higher in LEC rats than in the controls, especially in the liver at the acute stage of hepatitis. These findings suggest that oxygen radicals may be important in the carcinogenesis that occurs in LEC rats.
8-Hydroxy-2'-Deoxyguanosine↗
Molecular genetic analysis of the ABO blood group system: 1. Weak subgroups: A3 and B3 alleles.
We have determined the nucleotide sequences of the coding region in the last two coding exons of ABO genes (which occupy 91% of the soluble form of A1 transferase) from 7 individuals with weak subgroup phenotypes. Four of the individuals had an A3 phenotype and 3 individuals had a B3 phenotype. We determined the nucleotide sequences based on PCR followed by subcloning and DNA sequencing of the amplified fragments. Two cases of the A3 allele and 1 case of the B3 allele were found to contain a single-base substitution which resulted in an amino acid substitution. However, no other cases of A3 and B3 alleles were found to contain differences in this region. This finding demonstrates for the first time heterogeneity among these weak subgroups at the nucleotide level.
ABO Blood-Group System↗
Molecular genetic analysis of the ABO blood group system: 2. cis-AB alleles.
We have determined the nucleotide sequence of the coding region in the last two coding exons of ABO genes from two cis-AB individuals (genotype cis-AB/O) with no consanguinity. In this region, cis-AB alleles from these 2 individuals were identical to one another while different from the A1 allele by two nucleotide substitutions. Both of these nucleotide substitutions result in amino acid substitutions. The first substitution is identical to the one previously found in the A2 allele. The other substitution is found at the fourth position of the four amino acid substitutions which discriminate A1 and B transferases.
ABO Blood-Group System↗