Akira Nonoyama

Protection against oxygen-induced reperfusion injury of the isolated canine heart by superoxide dismutase and catalase☆

While oxygen-derived free radicals have been implicated in the pathogenesis of myocardial injury, the exact nature of this injury is still unclear. To test the hypothesis that oxygen-induced injury may influence the recovery of cardiac function from ischemic damage, we used an oxygen free radical scavenger, superoxide dismutase (SOD), together with catalase, during the reperfusion of isolated canine heart which had been subjected to 15 min of normothermic ischemic arrest followed by 2 hr of hypothermic cardioplegic preservation using a modified Collins solution. Determinations of thiobarbituric acid reactive substances and coenzyme Q10 within the myocardium showed that the treatment with SOD and catalase was capable of inhibiting lipid peroxidation induced by reperfusion. This inhibition was apparently associated with the improvement of myocardial energy metabolism and cardiac performance. Coronary flow was significantly higher in the heart treated with SOD and catalase during the working stage with a corresponding increase in oxygen consumption. Myocardial adenosine triphosphate (ATP) was partially, but significantly restored during reperfusion in these hearts whereas no restoration was observed in the heart without the enzymes. The treatment with SOD and catalase also improved left ventricular stroke work index and left ventricular maximum dp/dt at an early stage of the working mode. These results suggest that the use of SOD and catalase during reperfusion can protect the ischemic heart against reperfusion injury by scavenging oxygen-derived free radicals.

Total rupture of the left main bronchus successfully repaired nine years after injury.

A patient who sustained a traumatic rupture of the left main bronchus that was successfully repaired nine years later is presented, and reference is made to reports of similar instances in which operation has been performed more than five years after injury. Pulmonary function following operation improved progressively and proved the delayed repair to have been a reasonable decision.

Reperfusion injury induced by augumented oxygen uptake in the initial reperfusion period: Possible efficacy of extreme hemodilution

This study was designed to investigate the relationship between myocardial oxygen consumption and oxygen-induced myocardial injury. Dog hearts were exposed to 40 min normothermic ischemia and then reperfused for 10 min with three oxygenated perfusates containing different hemoglobin concentrations and with moderate hemodilution. The experimental groups consist of a moderate hemodilution group (Group M) receiving 8 g/dl of hemoglobin, an extreme hemodilution group (Group E) given 4 g/dl of hemoglobin, and a hemoglobin-free autologous plasma group (Group F). Hearts in the non-ischemic control group (Group C) were also perfused with moderate hemodilution throughout. In Group C, Group M and Group E, the O2 tension of perfusates was maintained at about 100 mmHg and in Group F, at over 300 mmHg. Oxygen extraction at 5 min after reperfusion in Group C was 14%, in Group M and Group E less than 10%, but in Group F 70%. Oxygen consumption in Group F was more than twice that in Group E and surpassed that in Group C. Group M also showed a significant increase in oxygen consumption compared with Group E at 5 min after reperfusion. Among the ischemic groups, Group E showed improvement of left ventricular function almost comparable to Group C accompanied by a rapid decrease in myocardial lactate, improved preservation of myocardial adenine nucleotides and prevention of myocardial lipid peroxidation. In contrast, Group F showed persistently higher values of lipid peroxides and lactate, the poorest recovery of adenine nucleotides, and impairment of left ventricular function.(ABSTRACT TRUNCATED AT 250 WORDS)

Pulmonary function after lobectomy in children under ten years of age

A long-term follow-up study on pulmonary function in twelve lobectomized children under ten years of age at the time of surgery was performed to determine the patterns of compensation. In the patients over ten years old at the time of the test performed over two years postoperatively, there was neither compensatory regeneration nor compensatory overdistension of the remaining lung tissue. However, there appeared to be an increase in the vital capacity, probably due to the growth of surrounding tissue such as thorax, respiratory muscles, and diaphragm. In contrast, the children tested under the age of eight years showed evidence of mild overdistension during the early postoperative period, but not at two years. There was no sign of overdistension in the patients over ten years of age at the time of testing.A long-term follow-up study on pulmonary function in twelve lobectomized children under ten years of age at the time of surgery was performed to determine the patterns of compensation. In the patients over ten years old at the time of the test performed over two years postoperatively, there was neither compensatory regeneration nor compensatory overdistension of the remaining lung tissue. However, there appeared to be an increase in the vital capacity, probably due to the growth of surrounding tissue such as thorax, respiratory muscles, and diaphragm. In contrast, the children tested under the age of eight years showed evidence of mild overdistension during the early postoperative period, but not at two years. There was no sign of overdistension in the patients over ten years of age at the time of testing.