Protein Metabolism and Exchange as Influenced by Constriction of the Vena Cava

Abstract

Workers in this laboratory have long been interested in the production of plasma proteins and the fluid exchange.which goes on between the circulating plasma proteins and various body tissues. Ascites comes into consideration in such relation and the experimental method of vena cava constriction was used to study the body protein exchange due to ascites. As the experiments continued it was obvious that this method presented an admirable technique for the study of ascites and some of the related medical problems. Furthermore, the ascites was not complicated by the presence of extensive liver pathology and was due to venous stasis in the portal area. Ascites was produced in the dog by placing a constricting aluminum band on the inferior vena cava between the diaphragm and the right auricle.This method of vena cava constriction was used by one of us (G. H. W.) in 19(O-10 to produce ascites. The partial obstruction was caused by sutures put in the vena cava to produce narrowing of the lumen. This condition would last many weeks and then the sutures would cut through with relief of the obstruction and complete absorption of large amounts of ascitic fluid in a matter of hours. In these experiments there was no significant liver pathology remaining after relief of the obstruction. As these earlier experiments were incidental to a study of liver abnormalities (17) they were soon discontinued.The tables below show clearly that vena cava obstruction and the resultant ascites may produce a considerable drain on protein reserve stores and a hypoproteinemia. As the ascitic fluid is removed at frequent intervals, there results a continuing internal plasraapheresis. The term plasmapkeresis as used here means the removal of whole blood with subsequent replacement of the red cells suspended in a salt solution. As the procedure is used day by day one observes an hypoproteinemia which can be maintained for months at an even level. This technique has been used extensively to study the production of new plasma proteins as influenced by diet factors

Experimental Ascites. Studies of Electrolyte Balance in Dogs With Partial and Complete Occlusion of the Portal Vein and of the Vena Cava Above and Below the Liver

“…Nitrogen balances, though carried out, were omitted from the graphs as similar studies have been reported in detail previously ( 1,3,4,6 …”

“…Nitrogen balances, though carried out, were omitted from the graphs as similar studies have been reported in detail previously ( 1,3,4,6 tial occlusion of the vena cava above the liver caused a prompt predictable increase in the formation of ascitic fluid, associated with a decrease in the levels of circulating plasma proteins. The amount of sodium in the ascitic fluid recovered by paracentesis was approximately equal to that given orally and it was possible to predict the amount of 50-5 I.…”

“…The daily dietary intake, therefore, was 14.5 milliequivalents of potassium, 8.5 milliequivalents of sodium, and 5.6 milliequivalents of chloride for animal 50-5, and was 17.0 milliequivalents of potassium, 9.0 milliequivalents of sodium, and 6.4 milliequivalents of chloride for the other experimental animals. Additional sodium chloride and potassium (neocurtasal) 1 were given orally in capsules in large amounts at appropriate periods indicated in the accompanying graphs. Water was allowed ad libitum.…”

“…The animals were carefully weighed at the same time each day. Determinations of plasma protein and ascitic fluid protein were made by methods previously described (1). A Perkin-Elmer flame photometer, model 52-A, supplied with an acetylene burner was used to determine potassium and sodium utilizing lithium as an internal standard by the method previously described (17).…”

“…Previous studies (1)(2)(3)(4)(5)(6) of experimental ascites primarily concerned with protein metabolism and exchange have emphasized the importance of sodium in ascitic fluid production. Recently, the importance of sodium retention in several forms of effusions and edema has been described by numerous observers (7)(8)(9)(10)(11)(12)(13)(14)(15) who have all directly or indirectly implicated the kidney in the causal relationships of this abnormality of sodium' metabolism.…”