Albumin and globulin circulation in experimental ascites; relative rates of interchange between plasma and ascitic fluid studied with C14-labeled proteins

Plasma containing carbon¹⁴-labeled albumin and globulin, obtained by feeding ε-C¹⁴D,L.-lysine to a donor dog, has been injected intravenously and intraperitoneally into recipient dogs with experimental ascites. The circulation and interchange of total plasma protein between circulating blood and ascitic fluid have been confirmed and the participation of both albumin and globulin in this interchange has been demonstrated. Labeled albumin tends to reach equilibrium in plasma and ascitic fluid in a shorter period of time (1 to 2 days) than does globulin (2 or more days), after administration of labeled plasma by either route. Evidence is presented that the rate of transfer of albumin across the peritoneal membrane is at least three times faster than that of globulin in terms of weight.

The occurrence in the rabbit of an acute phase protein analogous to human C reactive protein

The occurrence in the rabbit of an acute phase protein analogous to human C-reactive protein has been confirmed. The acute phase protein of the rabbit reacts with a special form of the pneumococcal somatic polysaccharide, designated Cx polysaccharide, in the same manner that the human C-reactive protein reacts with the classical C polysaccharide. The method of preparation and some of the properties of the Cx polysaccharide are described. The rabbit Cx-reactive protein has been shown to be remarkably similar to human C-reactive protein in its general properties and in the conditions which govern its appearance in the blood. It has been obtained in crystalline form, and appears to be antigenically distinct from the proteins of normal rabbit serum.

Anemia plus hypoproteinemia in dogs; various proteins in diet show various patterns in blood protein production; beef muscle,. egg, lactalbumin, fibrin, viscera, and supplements

Dogs with sustained anemia plus hypoproteinemia due to bleeding and a continuing low protein or protein-free diet containing abundant iron have been used in the present work to test food proteins and supplements as to their See PDF for Structure capacity to produce new hemoglobin and plasma proteins. The reserve stores of blood protein-producing materials are thus largely depleted in such animals and sustained levels of 6 to 8 gm. per cent hemoglobin and 4 to 5 gm. per cent plasma protein can be maintained for considerable periods of time. The stimulus of double depletion drives the body to use all protein building materials with the utmost conservation. This represents a severe biological test for food and body proteins and its assay value must have significance. Measured by this biological test in these experiments, casein stands well up among the best food proteins. The ratio of plasma protein to hemoglobin is about 40 to 50 per cent, which emphasizes the fact that these dogs produce on most diets about 2 gm. hemoglobin to 1 gm. plasma protein. The reason for this preference for hemoglobin production is obscure. The mass of circulating hemoglobin is greater even in this degree of anemia and the life cycle of hemoglobin is much longer than that of the plasma protein. Egg protein, egg albumin, and lactalbumin all favor the production of more plasma protein and less hemoglobin as compared with casein. The plasma protein to hemoglobin ratio is increased, sometimes above 100 per cent. Supplements to the above proteins of casein digests or several amino acids may return the response toward that which is standard for casein. Histidine as a supplement to egg protein increases the total blood protein output and brings the ratio of plasma protein to hemoglobin toward that of casein. Beef muscle goes to the other extreme and favors new hemoglobin production up to 4 gm. hemoglobin to 1 gm. plasma protein-a ratio of 25 per cent. The total amounts of new blood proteins are high. Lactalbumin as compared with casein shows a lower total blood protein output and a plasma protein to hemoglobin ratio of 70 to 90 per cent. Amino acid supplements are less effective. See PDF for Structure Fibrin is a good food protein in these experiments-much like casein. When fed over these 5 week periods it causes a sustained increase in blood fibrinogen. Folic acid in the doses given has no effect on the expected response to various diets. Peanut flour is a very poor diet for the production of new hemoglobin and plasma proteins. Small supplements of casein and beef show a significant response with improved output of blood proteins. Soy bean flour gives a poor response and wheat gluten a good response with adequate output of blood proteins. Visceral products show some variety. Beef heart is not as effective as beef muscle. Beef spleen, kidney, and pancreas give good responses but not up to casein. Pig stomach, beef brain, and calf thymus are below average. The plasma protein to hemoglobin ratio shows a narrow range (40 to 60 per cent) in experiments with visceral products.

The dominant role of the liver in plasma protein synthesis; a direct study of the isolated perfused rat liver with the aid of lysine-epsilon-C14

A direct study of the isolated rat liver perfused with oxygenated blood containing amino acids and lysine-ε-C¹⁴ has yielded facts indicating that the liver synthesizes practically all the plasma fibrinogen, the albumin fraction, and probably more than 80 per cent of the plasma globulin fraction. The response of the isolated perfused liver in protein synthesis is qualitatively and quantitatively analogous to that of the intact animal, notably in (a) the ability to discriminate between natural L-lysine and D-lysine, (b) the per cent of isotopic amino acid converted to CO₂, (c) the per cent utilized in liver and plasma protein synthesis. The results obtained with the perfused liver are compared and contrasted with those reported for tissue homogenates, minces, and slices.

Fractionation of plasma globulin for prothrombin, thrombokinase, and accessory thromboplastin

1. Crude globulin from more than 1,000 liters of citrated bovine plasma has been used in developing a procedure for moderately large scale separation of clotting factors. Fraction A, prothrombin, kinase, and thrombin fractions were prepared. Fraction A contained both kinase and accessory thromboplastin, the latter predominating when fraction A was diluted. 2. When prothrombin was activated by kinase, the rate of thrombin production was enhanced by the addition of platelets, or brain lipid, or dilute fraction A. These accessory thromboplastins caused this acceleration only when calcium chloride was added. Even with calcium, they were not effective unless kinase was present. 3. In contrast, the action of kinase was not entirely dependent on either ionic calcium or accessory thromboplastin. The concentrated kinase fraction activated prothrombin in the presence of excess oxalate. Although kinase often contaminates highly purified thrombins, it is probably distinct from thrombin. The ratio of kinase to thrombin was 100 times as great in the kinase fraction as in the thrombin fraction. 4. The kinase fraction, diluted 45,000-fold, to protein-nitrogen concentrations as low as 0.02 microgram per ml., accelerated the conversion of crude prokinase in three-stage tests. 5. The findings are consistent with the following concept of the basic enzymatic mechanism: See PDF for Structure It is now added that calcium and accessory thromboplastin exert their effects by impinging on the basic mechanism, in a chemically secondary or indirect manner.