The Effect of Methylene Blue on the Oxygen Consumption and Respiratory Quotient of Normal and Tumor Tissue
The American Journal of Cancer
Dickens and bimer (1930h) , from their studies of normal and tumor metabolism, concluded that there is a definite defect in the oxidation of carbohydrate by tumor tissue, since tumors possess both high glycolysis and low oxidative carbohydrate metabolism, a combination not found in normal tissues. Barron (1930) found that methylene blue increased the oxygen consumption of only those tissyes having aerobic glycolysis, and that this catalytic effect was roughly proportional to the fermentative
... er of the tissue. Thus, both human and animal tumors, which constantly possess an aerobic glycolysis-usually a marked one-showed an increase in the oxygen consumption of 19.2 to 116 per cent after the addition of methylene blue, which serves, therefore, as a respiratory enzyme. At the suggestion of Professor W. 0. Fenn, in vitro experiments wcrc conducted to test the possibility of supplementing the oxidative enzyme system of tumors by methylene blue so as to permit the oxidation of lactic acid and thus raise their respiratory quotient. With n normal type of metabolism the tumor cell might attain also a.norma1 growth. The results showed, however, that the R.Q. was not increased. APPARATUS AND METHOD Differential volumeters (Fig. 1) were used for the measurement of the gases (Fenn, 1927; 1928) , and the prccedure and technic employed were essentially those of Dickens and Simer (1930~) and of Fenn (1932) , with minor modifications of the apparatus and procedure. Difficulty was experienced in using the differential volumeter of the usual design at 37.5" C. with a large capillary because at this high temperature the thin kerosene of the index drop tended to creep over the bends a t the ends of the capillary into the stopcocks. Further, if the stopcocks are immersed in the water bath the grease becomes very thin and leaks more easily. To avoid these defects, the apparatus was modified so that the capillary was suspended in the water underneath the stopcocks, which remained just above the water level and in such a position that gravity tended to pull the plugs tighter into the sockets.