Thioacetamide and benzo(a)pyrene--induced alterations of the intrinsic viscosity of hepatocyte chromatin.

The nuclear hepatocytic chromatin showed to be sensitive to the harmful effects of thioacetamide (TAA) and benzo(a)pyrene (BP), a hepatic and a nonhepatic carcinogen. Intrinsic viscosity is a reliable indicator of the drug-induced chromatin changes. A single dose of TAA induced a reversible alteration of viscosity, but the same kind of treatment using BP resulted in persistent changes. The reasons of the different behaviour of chromatin, when subjected to the action of the mentioned carcinogens, are discussed.

Diffusible cholesterol as a risk factor in the biochemical stage of atherosclerosis.

The variations of diffusible cholesterol, considered as one of the risk factors involved in the biochemical processes of the subclinical, premorphologic stage of atherosclerosis, were studied in patients with cardiovascular disturbances. To this end, total cholesterol, diffusible cholesterol and beta-lipoproteins were assayed in the blood of 76 such patients and in their children. A correlation was observed between the increase of diffusible cholesterol values and those of beta-lipoproteins. In some of these cases, high diffusible cholesterol values showed a hereditary character.

[Study of the incorporation of radioactive zinc in Saccharomyces cerevisiae aldolase]. / Studiul încorporarii zincului radioactiv in aldolaza din Saccharomyces cerevisiae

Saccharomyces cerevisiae aldolase concentrates from the culture medium containing ZnSO4 a large amount of Zn which becomes a component part of the enzyme molecular structure. This was made evident by adding to the culture medium 65ZnSO4 and measuring the radioactivity of the aldolase extracted by a Phillips single channel analyzer.

[Study of purified aldolase from Saccharomyces cerevisiae, using irradiated fructose-1,6-diphosphate]. / Investigarea aldolazei purificate din Saccharomyces cerevisiae cu ajutorul fructozo-1,6-difosfatului iradiat

The interaction of an electromagnetic field with the enzymatic substrate-- the sodium salt of fructose-1,6-disphosphate--induces in the latter a new type of physical transition S leads to S. The enzyme, in this case Saccharomyces cerevisiae aldolase, is able to reveal this new state of the substrate by an increase in its specific activity within well established irradiation times. Each enzyme is characterized by the tm (minimal irradiation time of the substrate) a tau (fixed time period) parameters that delimit the two signals. Purified S. cerevisiae aldolase has tm=5 sec. and tau=20 sec., in contrast to muscle aldolase (represented by class I aldolase) which has tm=15 sec. and tau=30 sec. This may be attributed to the fact that most of the enzymatic systems in S. cerevisiae are made up of several distinct molecular forms, involved in more metabolic pathways than in the animal tissue, therefore with various responses to the phenomenon of perturbation of the substrates.

Electrophoretic investigation of L-asparaginase influence on blood and spleen blood globulins. Experimental study.

In view of detecting the influence of L-asparaginase on blood and spleen blood globulins, 42 rabbits were daily injected for three weeks with different doses of this drug. Electrophoretic analysis of blood and spleen blood samples from these animals showed no relationship between the doses used and the changes of circulating blood globulins indicating the well known immunodepressing effects of the drug. However, in the spleen blood from the inoculated rabbits (as compared with a control group) a small excess of gamma globulins which appeared especially after 1-2 weeks of daily injections with 2,000 or 10,000 I.U.L-asparaginase/kg b.w. was interpreted as due to the antigenic action of the enzymatic product administered.