Marta Romano

The action of crystalline lactate dehydrogenase from rabbit muscle on glyoxylate

Abstract The action of crystalline lactate dehydrogenase ( L -lactate: NAD oxidoreductase, 1.1.1.27) on glyoxylate, in the presence of NAD coenzymes, has been studied. It has been observed that this enzyme oxidizes and reduces glyoxylate simultaneously and generates oxalic and glycolic acids, respectively. The fact that both these substances are always produced together, independent of the form of coenzyme (oxidized or reduced) present in the incubation mixture, indicates that crystalline lactate dehydrogenase and glyoxylate generate a true oxido-reduction system of nicotinamide nucleotide coenzymes. In the presence of pyruvate the formation of glycolic acid is inhibited, while that of the oxalic acid is enhanced.

Levels of polyamines and nucleic acids in human breast carcinoma.

Polyamine and nucleic acid levels were determined in normal human breasts, in primary infiltrating ductal carcinoma breasts, in the uninvolved tissues of the same carcinoma-bearing breasts and in the urine of the same patients. The results showed that the production of polyamines in the carcinoma tissue is significantly higher than in normal tissue; the presence of a carcinoma in the breast does not modify the levels of polyamines and nucleic acids in the surrounding uninvolved tissue; spermidine and spermine are correlated both with DNA and RNA in the carcinoma; the urinary polyamine levels in the carcinoma-bearing patients were not significantly different from that of controls. There appeared to be a close relationship between polyamine biosynthesis and tumoral mammary cell development and a very fine control between the biosynthesis of both spermidine and spermine and nucleic acids. In addition, the localized solid breast carcinoma, with non-proven metastases, did not provoke an increase in polyamine excretion.

Differences in polyamine metabolism between carcinomatous and uninvolved human breast tissues.

The polyamine biosynthetic enzymes ODC and SAMDC show higher activity in carcinomatous human breast tissue than in uninvolved tissue of the same breast; the interconversion enzyme PAO shows significantly lower activity in carcinomatous than uninvolved tissue. The polyamine metabolism in carcinomatous human breast tissue thus appears to differ from that in uninvolved tissue. Intracellular polyamine concentrations, particularly spermine, are high in carcinomatous tissue. This increase and that of the biosynthetic enzymes suggest that a higher polyamine concentration is needed for carcinomatous cell growth. If this is the case, the lower PAO activity in carcinomatous tissue may be explained as a mechanism that conserves the high intracellular polyamine concentration.

Polyamine oxidase activity in carcinoma-bearing human breast: Significant decreased activity in carcinomatous tissue

The paper reports a comparative study of the activity and distribution of polyamine oxidase (PAO) in carcinomatous human breast tissue and in the healthy uninvolved tissue of the same breast. The results indicated that in the carcinomatous tissue the PAO activity is lower than in the healthy uninvolved tissue.

Polyamine oxidase activity in serum of cancer patients and healthy subjects

Polyamine oxidase (PAO) activity was determined in the serum of cancer patients and healthy subjects. However, the data obtained showed that PAO activity was extremely low or undetectable in the serum of cancer patients and healthy subjects. The difference in PAO activity observed between the sera of cancer patients and healthy subjects was statistically insignificant. Thus, the measurement of PAO activity in serum has no value as a cancer marker.

DNA and oestradiol receptor distribution in human breast cancer.

The content of DNA and oestradiol receptors was measured in two different samples taken from the same tumoral mass of 33 primary infiltrating ductal carcinomas. The results were related to the total cytoplasmic protein and to the DNA of the tissue. The results showed that variations of both DNA and oestradiol receptors are frequent and often significant. The reliability of analyses carried out on a single biopsy is discussed.

Polyamines and Nucleic Acids in Gestational Trophoblastic Tumors

To test the relationship between tumor malignancy and content and distribution of polyamines and nucleic acids, 2 forms of human gestational trophoblastic tumors were examined: the hydatidiform mole (self-limited form) and the human choriocarcinoma (invasive form) xenografted into nude mice. The results indicate that there are 2 significant differences between the choriocarcinoma and the mole: 1) the choriocarcinoma is characterized by increased polyamine and nucleic acid levels, 2) the 2 tissues differ in their putrescine:spermidine and spermidine:spermine ratios. There is an increase in polyamines in the urine of mole-bearing patients over that of normal controls. The correlation between putrescine and spermidine with the chorionic gonadotropin indicates that these 2 polyamines reflect the biological activity of the mole.

Sub-fractionation and characterization of lysine-rich histones from Oberling Guerin-Guerin's myeloma.

The H1 fraction in Oberling Guerin-Guerins myeloma was isolated, and an electrophoretic study was carried out in order to establish its composition. The results obtained show that the H1 fraction is heterogeneous and is formed of 2 sub-fractions. These were separated by preparative gel electrophoresis. They differ in molecular weight, electrophoretic mobility, and primary structure. Each sub-fraction exists in 2 different electric states.

Effects of Ionizing Radiations on the Activity of Valyl-tRNA Synthetase Isolated from Rat Liver and Morris Hepatoma 7777.

The effects of ionizing radiations on valyl-tRNA synthetase (L-valine tRNA ligase (AMP), E.C.6.1.1.9.), 100-fold purified from rat liver and Morris hepatoma 7777, are reported. The results showed that: 1) the enzymatic activity is strongly inhibited by radiations; 2) the enzymatic inactivation is much more marked in dilute than in concentrated solutions; 3) the inactivation of enzyme is linked to oxidation of sulphydryl groups indispensable to the catalytic activity of the enzyme; 4) no substantial difference in relation to inactivation by radiation was observed, between rat liver and Morris hepatoma 7777 enzymes.