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The efficacy of coronary venous retroinfusion of superoxide dismutase and catalase was studied in anesthetized closed chest dogs with 90-min left anterior descending coronary artery (LAD) occlusion followed by 3-h reperfusion. In group A, superoxide dismutase (2.5 mg/kg) and catalase (2.5 mg/kg) were administered by a 30-min continuous right atrial infusion beginning 15 min before reperfusion and supplemented by a bolus injection of superoxide dismutase (2.5 mg/kg) and catalase (2.5 mg/kg) through the great cardiac vein immediately before reperfusion. The treatment in group B was similar to that in group A, except that the bolus injection was into the right atrium. In the control group (group C), saline was administered in the same manner as in group A. Infarct size, expressed as a percentage of the risk area, was significantly smaller in group A (11.3 ± 8.9) than in groups B (31.3 ± 21.1) and C (43.0 ± 16.9; p < 0.05). Regional function of the ischemic zone measured by two-dimensional echocardiography exhibited significantly (p < 0.05) greater recovery after 3-h reperfusion in group A (30.3 ± 8.4) versus groups B (12.5 ± 13.7) and C (12.1 ± 11.7). Moreover, there were significantly fewer postreperfusion ventricular arrhythmias in group A as compared with groups B and C. The results of this study indicate that coronary venous retroinfusion is an effective method for delivery of superoxide dismutase and catalase.

The effect of intravenous nifedipine (5 µg/kg) on the recovery of myocardial function after occlusion of the left anterior descending coronary artery was studied in 18 closed chest dogs. Using computer-aided analysis of two-dimensional echocardiograms, systolic and diastolic function of ischemic segments in low papillary left ventricular cross sections were characterized, respectively, as holosystolic fractional area change and early diastolic velocity of luminal area change. The time required for systolic function to return to preocclusion values after a 1 minute untreated control occlusion (n = 12) was 5 to 10 minutes, and after a 2 minute occlusion (n = 6) it was 20 to 30 minutes. When nifedipine was administered during the occlusion, recovery after a 2 minute occlusion was accelerated slightly to 10 to 15 minutes.

Summary: From 75-08-18 to 75-08-26, the Netherlands Hydrobiological Society investigated during a field research trip the influence of the dimensions of a ditch on its aquatic communities. With regard to theCladocera no direct relationship was found between the dimensions of the ditch and the occurrence of certain species ofCladocera. A decrease in the number of species ofCladocera was assessed in the narrowest part of the ditch.

A contradiction has been shown in the conclusion of the theorem of Bailey and Chen on the global behaviour of the amplitude of an acceleration wave. The modified statement of the theorem is presented and proved. The conclusion has been illustrated by the calculation of the amplitude of an acceleration wave with a curved surface propagating in a relaxing gas.

Sudden and staged reperfusion after experimental coronary artery occlusion was studied in relation to recovery of cardiac function and postreperfusion arrhythmias. Eighteen closed chest dogs with 3 hour intracoronary balloon occlusion of the proximal left anterior descending coronary artery were studied using two-dimensional echocardiography over a period of 3 weeks after reperfusion. Nine dogs had sudden reperfusion by abrupt balloon deflation. In nine other dogs reperfusion was staged with partial reflow (20 ml/min) for 2 hours through the central lumen of the catheter during persisting intracoronary balloon inflation, followed by balloon deflation and full reperfusion.