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Biomedical subjects

G Danielescu

Publications and source records attributed to G Danielescu.

At least 19 recordsLinked to original sources
PubMed1975

The formation of virus polyribosomes in L cells infected with vaccinia virus.

The fate of early virus messenger RNA in the cytoplasm of vaccinia-infected L cells has been studied during the first hour after infection. The RNA is made in the virus core structure from which it is rapidly released. It accumulates in the polyribsome fraction, where at least 75% is bound to ribosomes through an EDTA-sensitive link. Three distinct structures have been identified as possible intermediates in virus polyribosome formation. The first is a ribonucleoprotein complex (RNP) in which virus RNA is associated with cellular proteins. A complex having apparently similar properties, is formed when virus RNA is added to a cytoplasmic extract in vitro. The other two structures may consist of an RNP moiety associated with the small ribosomal subunit, or with a single ribosome. At least part of the RNA isolated as RNP appears to be a precursor of the virus messenger found in polyribosomes.

Animals↗
PubMed1975

The effect of interferon on the formation of virus polyribosomes in L cells infected with vaccinia virus.

The effect of interferon treatment of mouse L cells on the fate of virus messenger RNA following infection with vaccinia virus has been studied. The polyribosomes of interferon-treated, infected cells are found to be disaggregated and it is proposed that htis results from inhibition of the initiation of virus polypeptide snythesis. Evidence is presented that inhibition of polypeptide chain elongation also occurs. The block in initiation appears to be due to the failure of the small ribosome subunit to attach to the virus messenger ribonucleoprotein complex. The translation of the different vaccinia messenger species is inhibited to a comparable extent.

Animals↗
PubMed1975

The presence of interferon and type A immunoglobulins in the nasopharyngeal secretions of volunteers immunized with an inactivated influenza vaccine.

The presence of interferon and type A immunoglobulins (IgA) was followed up in the nasopharyngeal washings collected from volunteers immunized intranasally with an inactivated influenza vaccine [strain A/Rom 1/73 (H3N2)]. Interferon was detected 24 hours after vaccine administration, its incidence being similar to that in the course of acute infection. Intranasal administration of inactivated influenza vaccine stimulated the production of secretory IgA in 3 of 10 samples collected 12 days after vaccination. At the same time, IgA were found in 4 samples collected before vaccination, and inhibited in certain cases the stimulation of interferon synthesis. The practical importance of the route of influenza vaccine administration is discussed.

Administration, Intranasal↗
PubMedDate not supplied

[The antiproliferative effects associated with vincristine and human interferons in experimental in vitro systems].

Cytotoxic potential of suboptimal doses of vincristine associated with human interferon was studied in two cell lines of tumoral origin, as compared to the action of or gamma type interferon preparations. Results show that the vincristine cytotoxic effect may be synergistically augmented in both culture types by simultaneous interferon administration.

Cell Division↗
PubMedDate not supplied

[Gamma interferon induced in human leukocytes by phytohemagglutinin: its production and biological characteristics].

Human gamma type interferon (IFN) preparations were obtained through phytohemagglutinin stimulation of leukocytes from the peripheral blood. Biological value of these preparations varied between 160 u and 800 u/ml, depending on leukocyte incubation medium, culture system and inductor conservation. The rising of the antiviral activity through association between gamma (3 u) and alpha (27 u) interferons was revealed by the virus quantity reduction (in this case the vesicular stomatitis virus was used) during a 24-hour multiplication cycle. The protection ensured by the mixture of the two types of interferon was about ten times higher than the additive effect of the two preparations. Study of the antiproliferative activity of a gamma interferon preparation was conducted on two human cell lines of tumoral origin (T-10 from a glioblastoma, and HEp-2) and revealed the difficulties to quantify precisely this property of the crude gamma interferon preparations.

Cell Division↗
PubMedDate not supplied

Investigation of humoral and cell-mediated immunity aspects in mice with experimental latent herpes infection.

An experimental latent herpes infection was established by intradermal inoculation of the mouse ear or of the footpad with a wild strain and a temperature-sensitive (ts) mutant of herpes virus type 2. The wild strain was latency-positive irrespective of the inoculation site; the ts mutant induced latent ganglionic infection only when inoculated in the footpad. Neutralizing antibodies could be detected only after inoculation of the wild strain. The establishment of latency was not prevented by the presence of either a humoral or a cell-mediated immune response.

Animals↗
PubMedDate not supplied

[Anti-proliferative and antiviral effects of human alpha-interferon on tumor cells].

Antiproliferative and antiviral activities of a type alpha human leukocytic interferon on several heteroploidic cell lines: HeLa, HEp-2, and T-10, a cell line of malignant origin (glioblastoma) were investigated, as compared to subcultures of human embryo fibroblasts. The tumor cell multiplication rate decreased proportionally to the amount of interferon in the culture medium. The highest interferon concentration used in our experiments (1,000 mu/ml) induced a decrease of the normal cell multiplication rate (human embryo fibroblasts). The same amount of interferon had a cytotoxic effect against the T-10 cells, but this phenomenon is reversible if the interferon is excluded after 24 h from the culture medium. There was no quantitative relation between the magnitude of the antiviral and of the cytotoxic effects of the type alpha human interferon on the tested cellular substrates.

Antineoplastic Agents↗