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Biomedical subjects

G Danielescu

Publications and source records attributed to G Danielescu.

24 records · Page 2Linked to original sources
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Investigations of the antiviral activity of some nitroso-urea derivatives. Inhibitory action of the IOB-252 nitroso-urea derivative on vaccinia virus incell cultures.

The nitroso-urea derivative IOB-252 was administrered in monkey kidney cell cultures in a concentration of 40 mug/ml 24 hours before inoculation of vaccinia virus and maintained afterwards in a concentration of 25 mug/ml. The drug inhibited vaccinia virus multiplication, hemagglutinin synthesis and late cytopathic effect, but did not prevent early cytopathic lesions. IOB-252 inhibited the synthesis of interferon initiated by a viral inductor and blocked the antiviral effect of an exogeneous interferon. The mechanism of action of the drug is discussed.

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PubMedDate not supplied

Persistent measles virus infection in a calf kidney cell line. Note I. Establishment of calf kidney cell lines chronically infected with measles virus and some of their biological characteristics.

Several types of persistent measles virus infection resulting in lytic infections could be established in a calf kidney cell line, according to the passage level of the substrate and to the virus strain inoculated. Persistent measles virus infection in calf kidney cells was characterized by the limited proportion of infected cells, the large amount of infectant virus, and the alteration of morphological and growth characteristics of the cells. The mechanism of this persistent infection is discussed.

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PubMedDate not supplied

Effect of interferon on virus-transformed and tumor cell lines.

The cell growth inhibitory action of rat interferon (IFN) was investigated in two systems: a cell line obtained by transformation of rat embryo fibroblasts under the action of a ts mutant of herpes simplex virus and a tumor cell line derived from tumors induced in rats by transformed cells. The growth inhibitory effect of IFN, evaluated by cell counting and colony formation in soft agar medium, was dependent on the exponential cell growth rate and on the concentration of IFN in the medium. Long-time subcultivation of the two cell lines in the presence of IFN did not result in the selection of a cell population resistant to the growth inhibitory effect of IFN, but led to a decrease in the oncogenic potency of the tumor cell line.

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PubMedDate not supplied

Investigation of the effect of cellular and viral nucleic acids on certain virus infections. Note 2. Effect of nucleic acids on virus multiplication in cell cultures.

Treatment of cell cultures with different natural nucleic acids prior to inoculation of herpes simplex virus type 1 led in certain cases to an obvious reduction in infectant titer. The reduction was maximum at a dose of 50 micrograms nucleic acid/culture tube and it was not dependent on the nature of the nucleic acid preparation. The antiviral effect of nucleic acids was enhanced by complexation with intercalation agents such as ethidium bromide or violamycin BI. No detectable amounts of interferon could be made evident in cell cultures treated with chromosomal DNA under conditions leading to a reduction by 1.75 log in infectant titer.

Aminoglycosides↗
PubMedDate not supplied

Investigations in the transforming activity of temperature-sensitive mutants of herpes simplex virus.

Transformation of rat embryo fibroblast was induced by a temperature-sensitive mutant of herpes simplex virus type 2. Transformation was scored using the morphological criterion of focus formation and the cell changes that lead to the final focus are described. Virus genome persistence in the transformed cell line was demonstrated by the presence of virus-specific membrane antigens and by the specificity of antibodies elicited in rabbits by inoculation of transformed cells. The cytogenetic analysis of the transformed cells revealed changes in chromosome number and the presence of marker chromosomes.

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