THE CATALYTIC EFFECT OF METHYLENE BLUE ON THE OXYGEN CONSUMPTION OF TUMORS AND NORMAL TISSUES

1. Methylene blue has no catalytic effect on the oxygen consumption of those normal adult tissues which do not possess aerobic glycolysis. The dye increases the oxygen consumption of these tissues when their respiration has been inhibited by the addition of KCN and their fermentative power thus brought into action. 2. Methylene blue increases the oxygen consumption of normal tissues having aerobic glycolysis, and of tumors. 3. The effect of methylene blue is roughly proportional to the fermentative power of tissues

COMPARISON OF THE REDUCING POWER OF SOME TYPICAL TRANSPLANTABLE TUMORS AND OF TUMORS PRODUCED BY FILTERABLE VIRUSES : WITH AN APPENDIX ON THE METABOLISM OF INFECTIOUS MYXOMA OF THE RABBIT

1. The tissues of Rous chicken sarcoma and of the infectious myxoma of the rabbit do not possess the oxidation-reduction enzyme succinodehydrogenase, which is present in normal tissues and in transplantable tumors. 2. Filterable virus diseases (rabbit Virus III, rabbit neurovaccine, rabbit herpes, fowl-pox) produce in the tissues affected by them a partial inhibition of succinodehydrogenase

STUDIES ON THE MECHANISM OF ACTION OF IONIZING RADIATIONS : II. INHIBITION OF SULFHYDRYL ENZYMES BY ALPHA, BETA, AND GAMMA RAYS

The activity of crystalline phosphoglyceraldehyde dehydrogenase and urease was decreased when dilute solutions of these sulfhydryl enzymes were irradiated with small doses of alpha rays from Po, beta rays from Si89, and gamma rays from Ra. Partial reactivation of the enzyme by addition of glutathione was obtained after inhibition with alpha rays. Evidence that these inhibitions are due to oxidation of the —SH groups of the enzymes was given by the irradiation of the mercury-mercaptide urease with gamma rays. This irradiated complex was completely reactivated by glutathione as was the non-irradiated enzyme. The ionic efficiency of all these ionizing radiations on inhibition of phosphoglyceraldehyde dehydrogenase was similar (ionic yield around 1). The sulfhydryl groups of crystalline phosphoglyceraldehyde dehydrogenase were titrated by enzyme activity measurements and by ferricyanide oxidation

STUDIES ON THE MECHANISM OF ACTION OF IONIZING RADIATIONS : VII. CELLULAR RESPIRATION, CELL DIVISION, AND IONIZING RADIATIONS

On x-irradiation of the eggs and sperm of Arbacia punctulata there was inhibition of respiration with relatively large doses, whereas there was an increase with small doses. The dose required to produce an increase of respiration depended on the degree of sensitivity of the cell to the effect of ionizing radiation. Sperm cells were more sensitive; then came fertilized eggs; unfertilized eggs were the least sensitive. The inhibiting effect of x-rays on cell division was observed even on irradiation with x-ray doses which produced an increase of respiration. These results are compared to similar effects produced by thiol reagents and are attributed to oxidation of the thiol compounds in the cell

THE CATALYTIC EFFECT OF DYES ON THE OXYGEN CONSUMPTION OF LIVING CELLS

From the experiments described in this paper and in those previously published it can be concluded that dyes which can be reversibly oxidized and reduced, act as catalysts for some oxidative processes taking place in the living cells, as is manifested by an increase in their oxygen consumption. It has been found that the catalytic power of the dyes on the oxygen consumption of starfish eggs (mature, unfertilized) is conditioned by two factors: the reduction potential of the dye and the permeability of the cell surface. Dyes whose E'o is towards the positive side of the aerobic reduction potential of the starfish eggs have a maximum catalytic effect. This catalytic power decreases as the E'o becomes more negative than the reduction potential of the cell and becomes nil beyond certain limits. When a dye cannot penetrate into the cell, its effect is greatly diminished as in this case only those oxidative processes taking place at the outer surface of the cell can be activated. Whether a dye can act as a catalyst or not is dependent on whether the normal consumption of oxygen by the cell is slower or quicker than the oxidation activated by the dye. The speed of this activation is correlated to (1) the speed at which the dye is reduced by the cell, and (2) the speed at which the leuco-dye is oxidized by the atmospheric oxygen. If one of these two processes is slower than the normal respiration, the dye cannot increase the rate of oxygen consumption (phenol indophenol at low concentrations which is kept reduced by the cell is very slowly reoxidized by atmospheric oxygen, on the other hand safranin and neutral red which are not reduced by the cell or at least too slowly reduced, though rapidly reoxidized by air). It will depend on these two reactions velocities whether a dye will act as catalyst (methylene blue and dyes with similar E'o which are quickly reduced by the cell and the leuco-dyes of which are relatively quickly reoxidized). Though this relationship between the reduction potential of the dyes and its catalytic power would seem in contradiction with the well known thermodynamic assumption that there is in general no distinct relationship between the potential and velocity of the reaction, we have pointed out from the literature some of the various experiments where one does recognize this connection

THE PYRUVATE METABOLISM OF SEA URCHIN EGGS DURING THE PROCESS OF CELL DIVISION

The eggs of Arbacia and starfish contained about 70 and 25 micrograms of pyruvate per gm. of dry cells respectively. Arbacia eggs utilized added pyruvate, although the O2 uptake did not increase. On fertilization the utilization of pyruvate increased sevenfold. This pyruvate seems to be metabolized, as in other cells, with diphosphothiamine as coenzyme. The diphosphothiamine content of fertilized and non-fertilized eggs was about 16 micrograms; that of sperm, 30 micrograms. Penetration of sperm into the egg and fertilization with cell division to the pluteus stage did not bring forth appearance of succino-dehydrogenase. The possible mechanism of fertilization and cell division is discussed

THE PATHOGENESIS OF EARLY OBSTRUCTIVE JAUNDICE

1. After experimental ligation of the bile ducts in dogs, two distinct processes are clearly manifested: first, the accumulation of the normally circulating bilirubin in the blood with its characteristic indirect Van den Bergh reaction for a period of several hours, and second, the subsequent appearance of the bile bilirubin giving the direct Van den Bergh reaction. It is possible that the first process may be due to a temporary reflex inhibition of the function of the liver cells due to ligation of the duct and comparable to the same phenomenon which usually occurs in the kidney when the ureter is ligated. The second process begins before any rupture of the bile capillaries is visible. Liver sections made 6 to 7 hours after obstruction show these bile capillaries dilated and extending between the liver cells in small distended pouches the blind end of these lying in contact with the pericapillary spaces. It is possible that bile may diffuse from these thin walled pouches into the perivascular lymph spaces, this diffusion being favored by the mounting pressure inside the bile ducts. 2. In early obstructive jaundice bile first appears in the lymph, but exclusion of the thoracic duct from the circulation by drainage causes a delay of only a few hours in the appearance of bile bilirubin in the blood stream. We must therefore conclude that after biliary obstruction bile enters the circulation both by way of the blood capillarieś and the lymphatics, although the latter route is the more important

STUDIES ON BLOOD CELL METABOLISM : I. THE EFFECT OF METHYLENE BLUE AND OTHER DYES UPON THE OXYGEN CONSUMPTION OF MAMMALIAN AND AVIAN ERYTHROCYTES.

1. The respiratory metabolism of non-nucleated mammalian erythrocytes is enormously accelerated and approaches the magnitude of the metabolism of the nucleated erythrocytes of birds on the addition of methylene blue (and certain other dyes), to a final concentration of 0.005–0.0005 per cent. 2. In the presence of methylene blue the respiration is accelerated even when M/1000 KCN is also present. 3. The accelerated respiration due to methylene blue occurs at room temperature but it is most active at 38°. 4. Methylene blue in the above concentration accelerates the respiration of avian (goose) erythrocytes to a much smaller extent than it does the respiration of the erythrocytes of mammalian blood, while the effect upon anemic goose blood seems to be less than it is upon cells of normal goose blood. 5. Owing to a rather large initial carbon dioxide formation in defibrinated blood on incubation, which may not be related to the immediate respiratory process, proper respiratory quotients cannot be obtained in whole blood. When the cells are separated from the serum and suspended in Locke's solution, respiratory quotients are obtained upon incubation comparable to those of other resting mammalian cells, as well as of the actively respiring erythrocytes of birds. 6. The hypothesis is advanced that methylene blue acts in the rôle of an oxygen carrier, supplying a substance which has disappeared from adult mammalian non-nucleated erythrocytes and restoring their metabolic activity to an extent comparable to that of the young immature forms, or to that of the actively respiring avian (goose) blood

REGULATORY MECHANISMS OF CELLULAR RESPIRATION : III. ENZYME DISTRIBUTION IN THE CELL. ITS INFLUENCE ON THE METABOLISM OF PYRUVIC ACID BY BAKERS' YEAST

The rate of the aerobic metabolism of pyruvic acid by bakers' yeast cells is determined mainly by the amount of undissociated acid present. As a consequence, the greatest rate of oxidation was observed at pH 2.8. Oxidation, at a slow rate, started at pH 1.08; at pH 9.4 there was no oxidation at all. The anaerobic metabolism, only a fraction of the aerobic, was observed only in acid solutions. There was none at pH values higher than 3. Pyruvic acid in the presence of oxygen was oxidized directly to acetic acid; in the absence of oxygen it was metabolized mainly by dismutation to lactic and acetic acids, and CO2. Acetic acid formation was demonstrated on oxidation of pyruvic acid at pH 1.91, and on addition of fluoroacetic acid. Succinic acid formation was shown by addition of malonic acid. These metabolic pathways in a cell so rich in carboxylase may be explained by the arrangement of enzymes within the cell, so that carboxylase is at the center, while pyruvic acid oxidase is located at the periphery. Succinic and citric acids were oxidized only in acid solutions up to pH 4. Malic and α-ketoglutaric acids were not oxidized, undoubtedly because of lack of penetration

REGULATORY MECHANISMS OF CELLULAR RESPIRATION : I. THE RÔLE OF CELL MEMBRANES: URANIUM INHIBITION OF CELLULAR RESPIRATION

Uranium as UO2(NO3)2 combines reversibly with proteins. The degree of dissociation of this combination depends, among other factors, on the H+ concentration. At pH 7.3 the U-albumin complex was easily dissociated on addition of citrate, while at pH 3.8 it was not. Uranium inhibited reversibly a number of enzyme systems. Uranium enzyme inhibitions could be reversed on addition of certain hydroxypolycarboxylic acids (citric acid, α-hydroxyaspartic acid, malic acid); in no case, however, did phosphate have any effect. In cell-free yeast juice, the fermentation of glucose-hexosediphosphate was inhibited by UO2(NO3)2. Slight reactivation occurred on addition of phosphate. In living yeast cells, the fermentation and oxidation of glucose was inhibited by small amounts of UO2(NO3)2 (7,7 micrograms per mg. dry weight), while the oxidation of acetic acid, ethyl alcohol, malic and citric acids, was not affected at all. U inhibition in living yeast cells at pH 7.3 was completely released on addition of small amounts of phosphate, adenosinetriphosphate, and citrate, while at pH 3.8 U inhibition was not released by phosphate and citrate. At saturation, one yeast cell contained 7.06 x 106 molecules of uranium. Lactic dehydrogenase was not inhibited by U while the oxidation of lactic acid by gonococci was inhibited. Addition of phosphate released this inhibition. The U inhibition of liver succinoxidase was unaffected by phosphate, while the U inhibition of the oxidation of succinate by E. coli was released by phosphate. It has been concluded from these experiments that U inhibition of cell metabolism is due to combination of the metal with the protein portion of the cell membrane. Uranium is presented as an example of surface inhibition