Slow Digestion Research Articles

Degradation of Fibrinogen by Proteolytic Enzymes

SummaryDegradation products of fibrinogen and fibrin resulting from the hydrolytic action of plasmin, trypsin, chymotrypsin and papain were prepared and the two major polypeptide fragments were found to have inhibitory effects on the coagulation mechanism including inhibition of thromboplastin generation and inhibition of the conversion of the fibrinogen to fibrin. The inhibitory actions of each of the isolated components were characterized specifically for their role in each of these coagulation functions.Both the slow (D) and fast (E) fragments of fibrinogen and fibrin hydrolysis by plasmin degradation showed equally inhibitory effects against fibrinogen to fibrin conversion by thrombin and fibrin monomer polymerization. The slow component of both was more inhibitory. Both fast and slow digestion products of tryptic hydrolysis inhibited thromboplastin generation and fibrinogen to fibrin conversion and fibrin monomer polymerization equally. The fast component of chymotrypsin hydrolysis showed greater inhibition against thromboplastin generation and fibrin monomer polymerization, than did the slow component. Only a slow moving (D) component was obtained with papain digestion. It had no inhibitory function against thromboplastin generation and only minimal effect against fibrin monomer polymerization. The mechanism of inhibition of the thromboplastin generation test by fibrinogen degradation products is a neutralization or inhibition of factor IX.

Studies on autodigestion, VII. Is digestion of the living tissues (claude bernard’s experiment) a local phenomenon?

In anesthetized bullfrogs, rabbits and a dog the effect of peptic and tryptic digestion of the hind legs on blood pH, CO2, O2, Cl and N.P.N. was observed. No constant significant change was found and the conclusion is drawn that Calude Bernard’s phenomenon can be explained as slow acid corrosion and subsequent digestion of devitalized tissues. The results confirm the necessity of assuming an additional factor (devitalization) of tissues in the occurrence of gastroduodenal ulcer. Alternation of peptic and trypic digestion greatly increased the rate of digestion.

SUBSTANCES AFFECTING ADULT TISSUE IN VITRO

Adult tissue is characterized by a lag period of several days preceding the onset of growth in vitro. Treatment of fresh adult tissues with trypsin before planting them in culture flasks stimulated the tissues to grow sooner and more rapidly. Best stimulation was obtained by slow digestion at low temperature. The tissues lost nitrogen during the digestion. Lowering the temperature from 22 degrees C. to 5 degrees C. reduced the digestion of aorta tissue much less than it reduced the digestion of casein. Washing the tissue after trypsin treatment resulted in better stimulation. Trypsin solutions of different degrees of purity, when diluted to equal activity toward casein, gave equal stimulation to the tissue growth. These included solutions of Northrop's crystalline trypsin and chymo-trypsin. Papain also stimulated growth in a similar manner. The results indicate that this stimulation of tissue growth is due entirely to proteolytic action. Cultures of adult fibroblasts (and some tumor cultures) having reached a state of retarded growth have been treated with trypsin to digest away most of the plasma clot (used as a medium). Fresh plasma has been added to renew the clot. This treatment has resulted in an immediate renewal of growth. Reasons are given for supposing that the cells produce an inhibitor in vitro which they deposit in the surrounding clot, and which is removed by the action of trypsin.

The Utilisation of Proteoses by Chicken Heart Fibroblasts Growing in vitro

ABSTRACT The growth of chicken heart fibroblasts in physiological saline media, e.g. Tyrode, is not materially increased by the addition of pure proteoses. In the presence of plasma, the addition of proteoses causes increased growth of the tissues, probably owing to the slow digestion of the proteoses to utilisable amino acids by the enzymes of the plasma. If small quantities of embryo extract are also present in the plasma, then the beneficial effect of the proteoses on the rate of growth is very greatly increased. A thermostable substance has been separated from Witte’s peptone, and from fibrin digests, which is capable of stimulating cells to increased activity and division. The activity of this substance is not dependent on the presence of plasma. The effective agent is associated with, or is actually, a heteroproteose, and its action is probably not to supply nitrogen, but rather to stimulate the cells in some other way. It is present in certain preparations of proteoses and partly accounts for their activity. Suggestions are put forward to account for the manner in which the various media described affect the rate of growth of the cells.

On the Relation of the Serum Ereptase (Peptidase) Titer to the Clinical Course in Pneumonia

During the course of recent years a number of investigators have emphasized the possibility that a definite relation exists between the inception of the crisis in pneumonia and the activation of the proteolytic ferments in the area involved. Edsall and Pemberton1 in particular have advanced this idea and endeavored to make the logical clinical application of hastening autolysis as a therapeutic measure in cases of delayed resolution. Later, Jobling2 studied the serum ferments and antiferment during the course of pneumonia, noting the fact that just preceding the crisis protease was demonstrable in the serum, while the antiferment began to diminish from the high titer prevalent throughout the early part of the disease. The fundamental idea underlying the several studies in this direction has been that, apart from the intoxication arising directly from and incident to the growth of the pneumococcus, toxic split products were probably absorbed from the exudate, which could be considered a mass of foreign protein undergoing slow digestion before the crisis. Active autolysis once underway, only the lower and nontoxic products of digestion would be absorbed, and the environment for the continued proliferation of the pneumococcus would become unfavorable, as Almagia3 has suggested. In this phenomenon the primary reaction is of course local and cellular, involving the liberation of sufficient leukoprotease from leukocytes to overcome the inhibiting factors. These latter are very probably the antiferment of the serum and the exudate. Of the varieties of proteolytic ferments involved in such a digestive process, the titer of the peptidase or ereptase during the course of pneumonia has not been studied. This form of enzyme activity would