How can we expect our students to be accurate when their textbooks and even reference books are inaccurate and misleading B P. Advances in Cancer Research 1, 503-548. The supernatant was treated with trichloroacetic acid and the lysine was isolated from the protein precipitate and from the filtrate. Dialyzates were then precipitated by alcohol, yielding about 40 mg. In the Jensen sarcoma of the rat, rat liver tumors, Ehrlich ascites tumor of the mouse, and regenerahg rat liver, component 134 P.
It would for instance be interesting to repeat the experiment with rats which had been partially hepatectomixed. As was pointed out previously, attempts to obtain suspensions of whole cells from mammalian tissues which retain the biochemical functions of the original tissue have, for the most part, failed. However since the results obtained with hemoglobin and the total proteins were essentially the same, they restricted their further studies to the total proteins. I n order to overcome some of the difficulties that arise as a result of these limitations in scope, a list of general references has been added to the bibliography. A d a 18, 573-575.
I t is now clear that the milk agent is not essential fo r the genesis of some of the tumors, and that the milk agent is not essential for the continuous growth of the neoplasms. It may be reasonable to assume that the marked lowering of the synthesis of liver catalase cannot occur without concurrently involving changes in the general iron metabolism and particularly in the hepatic iron reserve. Thus a specific protein is synthesized by cells which can be incubated under controlled conditions. It is interesting to note that in these experiments, while marked thymus involution was constantly induced, there was no evidence of concomitant adrenal enlargement. Advances in Cancer Research, 1, 339-396. These two findings of Zamecnik and his colleagues suggest, therefore, that the incorporation of amino acids into microsomes takes place in three steps as summarized in Fig.
Methods for the isolation of insulin on a microscale involving paper chromatography have now been devised by Light and Simpson 1956 and Grodsky and Tarver 1956. . Our original experimental results have since received full confirmation from all sides. Simkin has also fractionated guinea pig microsomes and obtained similar results Simkin, 1955; Simkin and Work, 1957 after injecting the animals with a complete mixture of C14-aminoacids. It is also contradicated by the more recent results of Nakagawa and Nakagawa 1956 who found homogenates of neither spleen, liver, nor kidney from normal rats to reduce liver catalase.
Relationship between Mitotic Rate and Protein Structure. They found that there was a good correlation between the rate of incorporation and rate of protein synthesis, but the peak of the latter came a little later than the peak of mitotic activity. It is possible that in order to reveal the effect of the extra supply of amino acids, the basal diet, on which the tumor bearing animals are maintained, should be of protein subdeficient type, as was used in our experiments. Previously, Winnick and his colleagues had studied the uptake of radioactive amino acids by a variety of chick embryonic tissues Cerarde et al. The isolation of the active fraction was first attained by a simple method of extracting human tumor tissues with water under heat and precipitating with alcohol; this yielded crude material active for mice in 50-100 mg. Francis and Winnick 1953 studied the amino acid and protein balance in cultures of chick embryonic hearts. In rats over 14 months old, the activity of the glycine samples from all the collagen fractions was very low.
The arrows indicate continuity between rough surfaced and smooth surfaced profiles. Further, in glycine there is a common precursor for the synthesis of the globin moiety of hemoglobin and the porphyrin. They, therefore, conclude that the phosphoproteins of the egg are maternally synthesized. With successful extension of these investigations to polycyclic hydrocarbons, gen- eralizations of utmost inlportance are feasible and susceptible to factual experimentation. In tests on Brown Leghorns, the inoculations were carried out without reference to pedigree so that no bias would be exercised for or against a hypothetical virus. Thus the D-isomers may be concentrated Christensen et al.
The editors and the publishers are to be congratu- lated for the initiation of a valuable series of publi- cations. These results are of interest in connection with the low levels of glutamine found in tumor tissue Kit and Awapara, 1953. In neoplastic disease there is a group of findings such as anemia, lowered hemoglobin, and decrease of plasma iron , in man as well as in animals, all pointing to the disturbance of iron metabolism. Plasma Protein as a Precursor of Tissue Protein. The liver tumor slices on an average synthesized 30-50% as much albumin as did a similar weight of liver slices. Finally, Koritz and Chantrenne 1954 have studied the relationship between the ribonucleic acid content of reticulocytes and their ability to incorporate amino acids in in vitro.
None of the similarly prepared fractions from the gastric juice of 11 patients suffering from diseases other than gastric cancer showed any activity. That substances in the blood can initiate mitosis is suggested by the results of Bucher et al. When the growth rate of a tumor has increased to such an extent that the tumor requires all the available building blocks for protein synthesis and the degradation products have little time to escape, it approaches this character. It seems unneccessary therefore to repeat the arguments again here. Similar results were obtained with methionine sulfoximine Rabinovitz et al.