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Biomedical subjects

L Holczinger

Publications and source records attributed to L Holczinger.

At least 37 records · Page 2Linked to original sources
PubMed1976

The effect of dibromodulcitol on the template activity of DNA chromatin and nuclei from Yoshida sarcoma cells.

It has been shown earlier that after in vivo administration, dibromodulcitol (DBD) reacts with DNA and to a greater extent with chromosomal proteins of Yoshida sarcoma cells. The present experiments were designed to show if the binding of DBD to the chromatin elements of Yoshida sarcoma cells causes any changes in RNA synthesis using either DNA or chromatin as template in bacterial RNA polymerase system. During 4 to 24 h following in vivo administration, DBD reduces the template activity of dna without detectable single-strand breaks in the template DNA in alkaline sucrose gradients. Using chromatin as template the same dose of DBD produces no or very slight inhibition of RNA synthesis. Measuring the DNA-dependent RNA synthesis in nuclei isolated from Yoshida cells of treated rats, the dose of DBD which markedly inhibited the template activity of DNA, resulted in a significant stimulation of the nuclear RNA synthesis. The increased RNA synthesis was not due to an inhibition of ribonuclease activity. The observed alterations of the transcriptive properties of chromatin and nuclei produced by DBD are interpreted as being due to a modification of the whole nucleoprotein structure caused by the interaction of DBD with both DNA and chromosomal proteins.

Animals↗
PubMed1976

A study of hyperlipidaemia induced by ascites tumours.

In mice four stages of hyperlipidaemia induced by Ehrlich ascites tumour could be distinguished. Hyperlipidaemia is characterized mainly by increased serum VLDL content accompanied by high triglyceride concentration. The only exception was the regressive stage III where the serum lipid level (VLDL) has temporarily decreased. From the results obtained with the simultaneous examination of the liver, mesenteric fat tissue, tumour cell and ascites plasma lipids, it may be concluded that the endogeneous fat mobilization induced by tumour cells via increased VLDL synthesis and secretion of liver will lead to hyperlipidaemia and to the total depletion of the lipid stores. Rapid and reversible fall in lipid level following the withdrawal of ascites fluid in tumorous animals demonstrated clearly the direct effect of the tumour cells on lipid-lipoprotein metabolism of the host organism.

Adipose Tissue↗
PubMed1975

Proliferation and morphology of ascitic cells as a function of age in cell culture.

Ascitic cells in the logarithmic growth phase increase the accumulation of glycogen particles in the course of explantation into suspension culture, probably due to the increasing arrest of glycogenolytic enzymes. At this age, a part of the cells are capable of restitution by exopinocytosis of the glycogen-containing vacuoles ia formation of cytoplasmic buds. Older cells, taken from the plateau-phase, pass atypical differentiation and ageing, are less capable of hindering the abnormal accumulation of glycogen and the hypervacuolisation. As a consequence, the cells finally degenerate and die.

Animals↗
PubMed1975

Changes in nucleolar number of ascites tumor cells treated with actinomycin D.

In the nuclei of Ehrligh and NK/Ly mouse ascites tumor cells the number of nucleoli varies between 1 and 10. The average nucleolar number is 3.3 +/- 1.3 for both tumors. This value as well as the distribution of nuclei with various nucleolar number are parctically constant between the 5th and 15th day of transplantation. The nucleolar changes resulting from the effect of a single 200 mug/kg i.p. dose of actinomycin D take place in two phases, almost in the same manner for both tumors. Within 24 hours the mean nucleolar number decreases by about 20 percent accompanied by a diminution of size of nucleoli. 15 to 20 percent of nuclei does not contain real nucleoli but has small spots showing nucleolus-like staining ("scattered" nucleolar cells). The second phase is characterized by a 25-35 percent increase in the mean nucleolar number followed by a nucleolar enlargement. The process returns to normal within 6-7 days.

Animals↗
PubMed1975

Effect of detergents and sucrose derivatives on the modified protein determination of Lowry.

The effect on the protein determination method of Lowry, as modified by Hartreee, of widely used detergents (sodium deoxycholate, sodium laurylsulphate, Triton X-100 and Triton WR-1339) and of sugar derivatives often used for preparing concentration gradients (sucrose, dextran, Ficoll and Metrizamide) was examined. Each of the compounds studied gave rise to a coloured product in the test; however, the correlation between concentration and optical density was usually nonlinear. The majority of these substances - especially Ficoll, Metrizamide and dextran - interfere with the procedure even at low concentrations, thus their elimination from the sample before protein determination is inevitable.

Centrifugation, Density Gradient↗