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Biomedical subjects

L Holczinger

Publications and source records attributed to L Holczinger.

14 recordsLinked to original sources
PubMed1988

Permanent metachromatic effect of 1,9-dimethyl-methylene blue on acidic mucopolysaccharides of mastocytes.

The 1,9-dimethyl-methylene blue (SERVA) has a very strong metachromatic reaction with sulphated mucopolysaccharides of mastocytes at pH = 1 (Tris-HCl buffer). This metachromasia is retained also at increasing pH (2.5-5), and is not affected either by the quality or by the concentration of the ions present (1/240 M Tris-HCl, and 0.2 M phosphate buffer). The smears do not need any special mounting medium, only Canada balsam. The metachromasia is preserved for a considerable length of time.

Animals↗
PubMed1979

Neutral lipids in DNA, histone and nonhistone fractions of Ehrlich ascites tumor cell chromatin.

Lipid content and composition of DNA, histone and nonhistone proteins of Ehrlich ascites tumor cell chromatin were investigated. All fractions contained varying amounts of lipids, mostly neutral lipids, with different quantitative distribution. The DNA fraction was characterized by elevated total cholesterol level (37%); the histone fraction by high glycerol ester content (62%); and the nonhistone protein fraction by high percentage of glycerol ethers (22%). The results suggest that neutral lipids are integral parts of tumor cell nucleoproteins.

Animals↗
PubMed1978

Neutral lipids in nuclei and chromatin fraction of young and old Ehrlich ascites tumor cells.

Determination of lipid content of Ehrlich ascites tumor cell nuclei devoid of the nuclear envelope and chromatin isolated from them revealed considerable amounts of neutral lipids present in both preparations. The neutral lipid content always exceeded that of the phospholipid. An age dependent accumulation of neutral lipids could also be observed. The chromatin fraction always contained relatively higher amounts of neutral lipids than the respective nuclei with a predominance of cholesterol esters.

Animals↗
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↗
PubMedDate not supplied

A multifactorial system controlling myeloid cell differentiation and division.

It has been demonstrated that mature granulocytes contain two stimulatory and three inhibitory factors of cell proliferation. Consequently, beyond the negative feedback inhibitor (chalone), myeloid cells are controlled presumably by other negative (inhibitory) and positive (stimulatory) mechanisms, in addition.

Animals↗
PubMedDate not supplied

Modulative effect of endogenous granuloid inhibitors on cell proliferation.

The particle-free crude extract of differentiated granulocytes (GCE) and the GI-1, GI-2, GI-3 proliferation inhibitory fractions (M.W. larger than or equal to 70,000 approximately 11,500 and less than or equal to 4000) were studied for the effects they exert on cultured cells. As shown by the curve, in bone marrow suspension cultures, in the dose range of 0.01-10.0 microng/ml, GCE maximally inhibits 3H-TdR incorporation into the DNA for 5.5 hours. In agar-gel cultures, 1.0-5.0 microng/ml of GCE reduces both the number (by 50.6-54.8%) and the size of the colonies formed. The manifestation of the inhibitory effect of GI-1, GI-2 and GI-3 fractions requires 2.5-3.5 hours. The inhibitors designated GI-2 and GI-2 are target-cell specific but they do not reduce 3H-TdR incorporation either in thymocyte suspension or HeLa monolayer cultures. On the other hand GI-1 inhibis the proliferation in HeLa cultures, as well. These endogenous inhibitors exert their optimum effect, even in a partially purified state at 2-4 orders or magnitude lower concentrations than does 1,2/5,6-dianhydrogalactitol (DAD), a cell-aspecific inhibitor used for comparison in the same system.

Alkylating Agents↗
PubMedDate not supplied

Changes in the rates of lipogenesis and hepatic triglyceride secretion in mice bearing Ehrlich ascites carcinoma.

The growth of Ehrlich ascites tumors (EAT) in mice induces hypertriglyceridemia and depletion of lipid stores. H-Riop: Swiss mice in early and late stages of tumor growth were examined to investigate whether an increase in liver synthesis of fatty acids (FA) and/or an increase in the liver triglyceride (TG) secretion rates (TGSR) would contribute to endogenous cancer-induced hypertriglyceridemia. Using 3H2O as tracer, FA synthesis decreased in the liver of tumorous animals. Hepatic TGSR also decreased during the development of hypertriglyceridemia. On the basis of these results, hypertriglyceridemia is probably not due to hyperproduction of lipids by the liver. In the late stage of tumor growth a considerable drop of FA synthesis also ensued in the adipose tissues, which probably participated in the loss of carcass lipids. At the early stage of tumor growth FA synthesis in the EAT cells was substantial in relation to the low lipid content of these cells, but in the late period FA synthesis slowed down, indicating that the triglyceride-rich "older" tumor cells obtained a large part of their lipids performed by the host.

Animals↗