Pulmonary circulation and loss of microspheres from the lung following acute XXXX .

@entity697 @entity1294 @entity4 @entity432 @entity35
The pulmonary vein from right upper lobe was ligated in 15 @entity35 while 15 others served as controls. Prior to occlusion, 15 mum microspheres were injected into the superior caval vein. Another population of 15 mum microspheres was similarly given 1 min, 10 min or 30 min after ligation. All @entity35 were killed 5 min after the second microsphere injection. The weight of the ligated lobe was 63% higher than that of the controls. This was probably due to @entity1294 since no significant @entity4 developed. Increased weight caused a reduction in the number of preocclusion microspheres per gram of tissue in the ligated lobe. In addition a gradual loss of preocclusion microspheres took place following pulmonary venous ligation. After 35 min of ligation, 30% of the preocclusion spheres had disappeared from the ligated lobe. Postocclusion flow through the pulmonary artery into right upper lobe was estimated by microspheres from the second injection, and averaged 5% of normal flow. Following acute @entity432 , a rapid dilatation of the bronchopulmonary communicating system probably takes place. By reversal of the flow in this system, blood and microspheres can be drained into the bronchial venous circulation. In spite of methodological problems caused by @entity697 and loss of microspheres after @entity432 , we consider the microsphere method to be useful for further studies of collateral lung circulation.
