No abstract

No abstract

The nature of the fluid draining from the kidney, after its artery was occluded, was investigated. Samples of systemic arterial blood, renal venous blood and urine were also analyzed. It was found that the fluid draining from the kidney after occlusion is a mixture of vascular blood and another fluid designated as "diluting fluid," each contributing half to the composite mixture. In volume the mixture is 26 per cent of the functionally distended kidney. With the assumption that the renal extracellular fluid can be considered a simple mixture of blood plasma and a cell-free fluid, the composition of the "diluting fluid" was deduced from the known compositions of vascular blood and total fluid draining. The ratios of its content in a given substance to that in systemic (or renal venous) plasma are: for Na and Ca, 1.0; K, 1.5; Cl, 1.2; PO4, 2.0; urea, 1.8; plasma protein, 0.3; albumin, 0.4; glucose, 0.4, and osmolarity, 1.2. The fluid bears little or no relation to urine, especially since the urine varied considerably between individual dogs whereas the "diluting fluid" was relatively constant in composition. It was also found that the hematocrit of the fluid draining after arterial occlusion progressively decreased as it flowed out, until the last portion contained only 5 per cent red cells. It is concluded that since renal lymph has approximately the same composition in protein, urea, glucose, and inulin as does "diluting fluid," the latter is, in all probability, renal interstitial fluid. Under the conditions of the experiment, it drains out of the kidney slowly relative to blood drainage. It is large in volume, particularly when compared with the capillaries that nourish it. Its high protein content explains the observation that the kidney is apparently naturally distended with a fluid disproportionately rich in plasma protein.

A systematic investigation was conducted during the process of anoxic death in newborn pups, rabbits and kittens less than 24 hr. old. Simultaneous measurements of respiration, heart rate and blood pressure were made. Considerable individual variation in the respiratory responses of newborn animals breathing nitrogen was noted. Under hypoxic conditions, respiratory failure may follow circulatory failure in the adult, whereas in the newborn, respiratory failure always occurred long before circulatory failure. The effect of anoxia on the cardiovascular system of the newborn at the time of the last breath was not as pronounced as might have been anticipated. Great individual differences with respect to blood pressure and heart rate throughout the period of anoxia were noted. The systolic blood pressure, on the average, was seen initially to fall more rapidly than the diastolic blood pressure or heart rate; it then slowly tapered off. The circulatory system was noted to function, although at hypotensive levels, for long periods of anoxia. Submitted on June 29, 1959

No abstract

No abstract

No abstract

It has long been known that the kidney, in its functioning state, is distended with blood (1-4). Rose-Bradford (1) stressed the "passive" character of this distension, for he noted that the kidney swelled when the blood pressure rose and shrank when it fell. Text- fig. 1 shows how the organ collapses when its circulation is abruptly cut off; in this instance, although drainage was obviously incomplete, it shrank from a volume of 49 cc. to a volume of 39 cc., showing that at least 20 per cent of its normal functioning volume was distending fluid. This fluid drains from the renal vein when the renal artery is occluded; in quantity, when drainage is complete, it averages 26 per cent of the functionally distended kidney (5, 6).This aspect of renal behavior has, however, been overlooked by those investigating the functional vascular morphology of the organ. Led recently by Trueta el al. (7), many studies of blood distribution have been attempted, using particularly the technic of injecting India ink into the vascular system and then, at necropsy, examining the distribution of ink. In such studies, the distribution of ink at necropsy should reflect the distribution while the organ is functioning. But if the kidney's blood were to drain out after removal, the subsequent localization of the dye would give only very rough information about the distribution of blood in the functioning organ. The latter is not thoroughly known and hence the present study was undertaken.Actually, the fluid naturally distending the kidney is not blood alone; rather, it is a fluid containing less red cells and less plasma protein than simultaneously drawn blood, the same amount of Na and Ca, and increased quantities of K, C1, urea, and PO4 (6). Because kidney interstitial fluid (or lymph) has approximately this same composition, we have concluded that the distending fluid is very probably a mixture of blood and interstitial fluid. Furthermore, since the distending fluid contains only about half the red cells that blood contains (6), the volume of its two components, in terms of percentage of the functionally distended kidney, is 13 per cent blood and 13 per cent interstitial fluid.