Biomedical subjects

H Orita

Publications and source records attributed to H Orita.

At least 109 records · Page 6Linked to original sources

PubMed1990

[Preventive effect of post-ischemic reperfusion injury by terminal Nicorandil-Mg cardioplegia].

In this study, we evaluated the preventive effect of post-ischemic reperfusion injury by Nicorandil-Mg cardioplegia (Nic: 8 mg/l, Mg: 20 mEq/l) given just prior to reperfusion as "terminal cardioplegia". Nineteen dogs were placed on cardiopulmonary bypass and the aorta was cross-clamped for 90 min under hypothermic (17-19 degrees C) cardioplegic arrest. The hearts of ten dogs were reperfused without terminal cardioplegia (Group A). In the other nine dogs, terminal cardioplegia was given for 2 min prior to reperfusion (Group B). During and after a period of ischemia, myocardial tissue calcium ion (t-Ca) and PCO2 (t-PCO2) were continuously monitored by ISFET (ion sensitive filed effective transistor) sensor. Myocardial tissue blood flow, oxygen consumption and lactate flux were calculated at 5, 10, 20, 40 min of reperfusion. And myocardial function was evaluated at 45 min of reperfusion. In the initial reperfusion period, Group B showed an improved myocardial tissue blood flow compared to group A (at 5 min of reperfusion in group A: 29.4% of control, in group B: 42.7% of control, p less than 0.025). T-Ca and T-PCO2 in Group B were rapidly and significantly decreased at 5 min of reperfusion (t-Ca in group A: 2.8 +/- 0.5 mM----1.7 +/- 0.5 mM, in group B: 3.1 +/- 0.6----1.2 +/- 0.4, p less than 0.05; t-PCO2 in group A: 117.5 +/- 23.0 mmHg----82.5 +/- 17.4 mmHg, in group B: 127.5 +/- 22.5----42.5 +/- 9.7, p less than 0.001), and group B had better metablic recovery evaluated by myocardial oxygen consumption and lactate flux.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1990

[A clinical study of cerebral perfusion during pulsatile and nonpulsatile cardiopulmonary bypass].

The purpose of this study was to determine the effect of pulsatile flow on cerebral perfusion under cardiopulmonary bypass (CPB). Twenty-three patients who underwent cardiac operations were divided into two comparable groups: Group A (N = 11) had standard nonpulsatile flow, while in Group B (N = 12), a pulsatile pump was used. The blood flow of left common carotid artery and radial arterial pressure were continuously monitored during cardiac operation in both groups and cerebral vascular resistance was calculated. In Group B, the perfusion pressure of left common carotid artery was monitored and compared with that of radial artery. Arterial and internal jugular venous blood were sampled and the difference of cerebral A.V O2 contents and cerebral oxygen consumption was calculated. Cerebral vascular resistance in Group B (54.0 +/- 11.2% of the value of before-CPB) significantly decreased compared to that in Group A (72.2 +/- 11%) at the end of CPB (p less than 0.05). Pulse pressure following pulsatile CPB flow was 15.1 +/- 5.8 mmHg monitored in radial artery and it reduced to 8.5 +/- 5 mmHg in left common carotid artery. Although there was no significant difference in cerebral oxygen consumption of both groups during and just after CPB, the difference of cerebral A-V O2 contents of Group B was greater than Group A just after CPB. These data suggest that pulsatile flow may minimize the cerebral microcirculatory shunt during CPB, resulting from the reduction of cerebral vascular resistance.

Aged↗

PubMed1990

[Right heart bypass operation of complex cardiac anomalies in 4 patients with viscero-atrial heterotaxic syndrome].

Four patients with viscero-atrial heterotaxic syndrome underwent a right heart bypass operation. 2 patients had right isomerism, and two had left isomerism. 3 patients had common atrio-ventricular canal, three had double outlet right ventricle, one had mitral valve hypoplasia, and one had double inlet right ventricle. All patients had anomalous systemic or pulmonary venous drainage. Redirection of systemic venous drainage was accomplished by total cavo-pulmonary shunt (TCPS) (2 patients), atrial baffle (1 patient), and intraatrial conduit (1 patient). In one patient underwent TCPS, regurgitant common atrioventricular valve was replaced with a prosthetic valve. One who had total anomalous pulmonary venous drainage (type Ib) died after cardiac repair. The three survivors are in improved condition. The right heart bypass operation, like total cavopulmonary shunt or connection, simplifies the redirection of systemic venous drainage and offers improved results in the surgical treatment of complex cardiovascular anomalies with viscero-atrial heterotaxic syndrome.

Abdomen↗

PubMed1990

[Surgical correction for a case of partial anomalous pulmonary venous drainage with dextrocardia, situs inversus and azygos continuation of inferior vena cava].

An adult case of partial anomalous pulmonary venous drainage of left pulmonary veins with dextrocardia, situs inversus and azygos continuation of inferior vena cava is reported. Surgical repair was accomplished by constructing a baffle to direct the blood flow from left pulmonary veins to the left atrium through the created atrial septal defect. This case is a rare type of PAPVD.

Abnormalities, Multiple↗

PubMed1989

Modulation of proline and glucosamine incorporation into tissue repair cells by peritoneal macrophages.

The purpose of this study was to determine the patterns of [14C]proline and [14C]glucosamine incorporation by tissue repair cells (TRC) as modulated by postsurgical macrophages. Rabbits underwent a midline laparotomy followed by resection (2.0 cm) and reanastomosis of their ileum. Another group of rabbits underwent peritoneal wall abrasion with sterile gauze until punctate bleeding developed. Postoperative (1-28 days) exudate cells (PEC) were recovered from the peritoneal cavity after reanastomosis, and (TRC) were obtained directly from the injured peritoneal surface after abrasion. Since the postsurgical exudate was composed mainly of macrophages, we examined the effect of postsurgical macrophage-spent media on the incorporation of [14C]proline, [14C]glucosamine, and [3H]thymidine by TRC. After 7 days of culture, Postsurgical Day 7 TRC were incubated with spent media from postsurgical PEC (greater than 90% macrophages). When TRC were cultured with macrophage-spent media, the number of TRC increased significantly compared to that of fresh medium-treated controls. The incorporation of [3H]thymidine by TRC was also enhanced by macrophage-spent media. The incorporation of [14C]proline and [14C]glucosamine by TRC was also enhanced when incubated with macrophage-spent medium. However, when data were expressed on a per cell basis, incorporation of [14C]proline and [14C]glucosamine by TRC cultured with macrophage-spent media was the same or less than that by cells incubated with fresh medium. These data suggest that the increase in incorporation of glucosamine and proline into connective tissue protein by postsurgical repair cells may be directly modulated by macrophages recruited in response to surgical injury and that this increase is due to the fibroproliferative effect of postsurgical macrophages.

Animals↗

PubMed1989

Brain tissue pH, oxygen tension, and carbon dioxide tension in profoundly hypothermic cardiopulmonary bypass. Comparative study of circulatory arrest, nonpulsatile low-flow perfusion, and pulsatile low-flow perfusion.

The pH, oxygen tension, and carbon dioxide tension of canine brain tissue were experimentally examined during profoundly hypothermic cardiopulmonary bypass. After core cooling, a 60-minute period of circulatory arrest was performed in group 1 (n = 8), a 120-minute nonpulsatile low-flow perfusion (25 ml/kg/min) in group 2 (n = 8), and a 120-minute pulsatile low-flow perfusion (25 ml/kg/min) in group 3 (n = 8). When the animal was rewarmed, the core temperature was raised to 32 degrees C. Brain tissue pH kept decreasing in group 1, but it showed a delayed recovery in group 2 and a rapid recovery in group 3 during core rewarming. Brain tissue oxygen tension decreased significantly in group 1. Brain tissue carbon dioxide tension increased irreversibly in group 1, increased to about 100 mm Hg and recovered to 89.9 +/- 15.3 mm Hg in group 2, and reached a plateau of about 85 mm Hg and recovered to 55.4 +/- 6.7 mm Hg in group 3. We concluded that a 120-minute period of nonpulsatile low-flow perfusion provides more protection from brain damage than a 60-minute period of circulatory arrest. Furthermore, pulsatile flow will increase the safety margin of cardiopulmonary bypass even if the flow rate is reduced to 25 ml/kg/min.

Animals↗

PubMed1989

[Pulsatile assistance for profoundly hypothermic circulatory arrest, low-flow perfusion, and moderate-flow perfusion: comparative study of brain tissue pH, PO2, and PCO2].

The pH, oxygen tension, and carbon dioxide tension of canine brain tissue were experimentally examined during profoundly hypothermic cardiopulmonary bypass with and without pulsatile assistance. After core cooling, a 60-minute of circulatory arrest was performed in group 1 (n = 16), a 120-minute of low-flow perfusion (25 ml/kg/min) in group 2 (n = 16), and 120 minute of moderate-flow perfusion (50 ml/kg/min) in group 3 (n = 16). The core rewarming was done to the temperature above 32 degrees C. Each group was divided into two subgroups with and without pulsatile assistance (subgroup-p; n = 8, subgroup-c; n = 8). In group 1, progressive brain tissue acidosis and hypercapnea were recovered by use of pulsatile assistance. In group 2, brain tissue acidosis and hypercapnea were recovered completely with pulsatile assistance, but incompletely without it. In group 3, mild acidosis and hypercapnea were eliminated with pulsatile assistance. Brain tissue hypoxia was severe in group 1, slight in group 2, but not found in group 3. We conclude that a pulsatile assistance provides brain protection at any flow-ratio, and that the less flow-ratio and the longer perfusion period will make the pulsatile assistance the more necessary.

Animals↗

PubMed1989

[Effect of myocardial preservation and preoperative left ventricular end-diastolic pressure upon the early postsurgical cardiac function after prosthetic cardiac valve replacement].

We investigated the effect of myocardial preservation and preoperative stroke work index (SWI) and left ventricular end-diastolic pressure (LVEDP) upon the early postsurgical kinetics of left ventricular function in thirty-four patients after prosthetic cardiac valve replacement. They received both-sided cardiac catheterization and measurement of cardiac output by dye dilution method in a standard fashion. Myocardial temperature was measured simultaneously and consecutively during aortic cross-clamping period (greater than 70 min) on open heart surgery. Thereafter, each postsurgical left ventricular function was estimated at three, six, twenty-four and forty-eight hours after weaning from cadiopulmonary bypass (CPB) by using Swan-Ganz catheter. SWI0 X 1000/AnI was used as an improved index of postsurgical cardiac function, because it was incorporated with the preoperative left ventricular stroke work index (SWI0) and anoxic index (AnI), which was the integral of myocardial temperature during aortic cross-clamping period. Otherwise, we regarded LVEDP as an estimate of preoperative cardiac function. So we compared them with the early postsurgical left ventricular SWI, respectively. As a result, the relation between SWI0 and the postsurgical SWI (SWI24 and SWI48) showed positive correlations with correlation coefficients 0.52 and 0.70, and the relation between AnI and the early postsurgical SWI (SWI3 and SWI6) showed negative correlations with correlation coefficients -0.56 and -0.52. While the relation between SWI0 X 1000/AnI and postsurgical SWI (from SWI0 to SWI48) showed positive correlations with correlation coefficients decreasing from 0.76 to 0.57. LVEDP showed negative correlations to SWI0 and SWI48 with correlation coefficients -0.48 and -0.45.(ABSTRACT TRUNCATED AT 250 WORDS)

Adult↗

PubMed1989

[Increased lipid peroxides generation and calcium fluxes in hearts during reperfusion].

To investigate the evidence for free radical generation and calcium influx as reperfusion injury, we studied the time course of lipid peroxides generation and calcium content in hearts during reperfusion. The study was performed in patients who had valve or coronary disease, and underwent open heart surgery. Lipid peroxides activity in plasma during reperfusion showed a significant (p less than 0.01) rise to a peak on 5 minutes of reperfusion (1.45 +/- 0.07 nmol/ml; mean +/- sem) compared to the level before reperfusion (1.37 +/- 0.07 nmol/ml) (n = 20). The lipid peroxides generation well correlated with aortic cross-clamp time (r = 0.6384, p less than 0.01). On the other hand, the atrial calcium content after 5-10 minutes of reperfusion was 118.5 +/- 14.9% of the level before cardiopulmonary bypass (n = 15), calcium/magnesium was 124.5 +/- 8.9% (p less than 0.05). That increase ratio well correlated with aortic crossclamp time (r = 0.5948, p less than 0.05). These results have produced evidence of increased oxidant activity and calcium influx in hearts during reperfusion. These results suggested that abnormal lipid peroxidation happened during reperfusion, and these peroxidation of the cell membrane might cause the membrane damage and then calcium influx.

Adult↗

PubMed1989

[Comparison of cold blood cardioplegia and cold crystalloid cardioplegia with or without magnesium].

Blood cardioplegia has recently been advocated as a superior method of myocardial protection, but its temperature is important, and it has not been compared to a magnesium containing crystalloid cardioplegia. This study was undertaken to compare the protective effect of cold blood cardioplegia (BCP) and cold crystalloid cardioplegia with or without magnesium (MgKCP and KCP). Fourty-five patients were undertaken prosthetic cardiac valve replacement with left ventricular volume overload from valvular regurgitation. They were divided into three groups for the difference of the cardioplegic solution. Intraoperatively, myocardial temperature and the tissue PCO2 was monitored, and the content of calcium and magnesium of right atrium was measured before and after aortic cross clamping. Postoperatively, left ventricular stroke work index and serum CPK-MB isozyme activity were measured at 3, 6, 24 and 48 hours after weaning from cardiopulmonary bypass. The increase of the tissue PCO2 during aortic cross clamping and its recovery at ten minutes after reperfusion were significantly suppressed in BCP. The retension of the tissue calcium after reperfusion and calcium to magnesium ratio were significantly low in MgKCP. The recovery of cardiac pump function and decrease of CPK-MB were superior in MgKCP.

Cardioplegic Solutions↗

PubMed1989

[Effect of magnesium containing cardioplegic solution on the cases of extended aortic cross clamping].

We have investigated about the preservation of myocardium using magnesium containing cardioplegic solution. In this study we have concluded that magnesium containing cardioplegic solution is effective especially in the cases of extended Aortic cross clamping. 91 cases were availed for studying the post-operative cardiac function, and 32 cases of which were availed for seeking the content of calcium and magnesium of the myocardium. GK-Mg solution was superior in the post-operative cardiac function, and in the total CPK-MB. The retention of calcium in the myocardium after Ao declamping was higher in the cases of using GK solution. And Ca.Mg ratio was also higher in GK solution. Especially in the cases of extended Ao cross clamping, increase of calcium in the myocardium and Ca.Mg ratio was suppressed by using the GK.Mg solution. Although magnesium have several effects on the myocardium, but we think that suppressing the influx of calcium into the myocardium is one of the most important factor of the magnesium for the preservation of myocardium.

Aorta↗

PubMed1988

Ceftizoxime level in the myocardium (right atrial muscle and mitral papillary muscle) during open heart surgery.

We determined the level of sodium ceftizoxime (CZX) in the right atrium and mitral papillary muscle of 22 adults and 6 children undergoing open-heart surgery, 60 and 120 minutes after intravenous administration of this drug at the dosages of 2 grams for adults and 1 gram for children. The CZX level in the right atrial muscle after 60 minutes was 37.0 micrograms/g in adults and 51.0 micrograms/g in children. The CZX level in the papillary muscle of the mitral valve, determined at 120 minutes was 16.9 micrograms/g. In the present study, we measured the level of the antibiotic CZX in the myocardial tissue during open-heart surgery. The purpose of this was to determine the quantity in which the antibiotic is taken into the myocardial tissue.

Adult↗

PubMed1988

Myocardial tissue pCO2 and calcium content during ventricular fibrillation and reperfusion periods.

Forty-one patients who underwent cardiac surgery under conditions of systemic hypothermia and intermittent cold crystalloid potassium cardioplegia were studied, in order to elucidate the effects of ventricular fibrillation and reperfusion on the myocardium, by using the intramyocardial pCO2 and temperature sensor. All patients were assigned to 2 groups, namely; group A (21 cases), in which the time between the aorta declamping and defibrillation was under 10 minutes, and group B (20 cases) in which the time was over 10 minutes. In both groups A and B, myocardial pCO2 increased at the rate of 3.58 +/- 1.70 and 2.16 +/- 0.62 mmHg/min (p less than 0.05) after aorta declamping, respectively and the myocardial pCO2 decreased at the rate of 5.59 +/- 0.60 and 4.18 +/- 0.76 mmHg/min (p less than 0.05) after defibrillation, respectively. In group A, the myocardial calcium content, pre-CPB (cardio pulmonary bypass) was 10.98 +/- 1.62 nmol/mg/dry weight and at the time of aorta declamping it was 15.90 +/- 1.81 nmol/mg/dry weight (p less than 0.05). In group B, the myocardial calcium content, pre-CPB, was 14.62 +/- 2.15 nmol/mg/dry weight and at the time of aorta declamping it was 18.23 +/- 4.36 nmol/mg/dry weight (p less than 0.05). At both three and six hours after the operation, the left ventricular work index per minute (LVWI) in group A showed better cardiac pump function than that in group B. We therefore conclude that when reperfusion is encountered, acidosis can be minimized by prompt defibrillation.

Body Temperature↗

PubMed1988