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L L Mironova

Publications and source records attributed to L L Mironova.

At least 19 recordsLinked to original sources
PubMed1994

[An analysis of the chromosomal combinations in dicentrics with induced telomeric fusion].

Chinese hamster heteroploid cell culture was treated by colcemide for 42 h, of which within the first 17 h by 5-bromedeoxyuridine. Dicentric chromosomes, that were formed at the 2nd mitosis after colcemide administration, were analysed using G-banding. Of 211, only 40 were made of heterological dicentrics. Other 171 dicentrics were formed by telomeric fusion of autological chromosomes. No correlation was found between the length, centromeric index and frequency of dicentric formation. A probability of telomeric fusion of chromosomes determined by nucleotide sequences specific for each chromosome is proposed.

Animals↗
PubMed1989

[Telomeric fusion of the chromosomes in cells with micronuclei during the subsequent incorporation into the DNA of thymidine halogenated analogs].

As was shown elsewhere among halogenated analogs of thymidine there exist strong (5-chlorodeoxyuridine, 5-ChldU) and weak (5-iododeoxyuridine, 5-IdU) inducers of dicentric chromosomes in cells with micronuclei. Since from colcemid administration to the moment of fixation two cycles of replication are passed, a study was made of the pattern of induction of dicentric chromosomes under subsequent administration of 5-ChldU and 5-IdU, and the other way round. It was shown that the pattern of induction of dicentric chromosomes was strong or weak, and depended on the fact which analog was administered in the first S-period.

Animals↗
PubMed1989

[Preparation of diagnostic antitoxic serum to Clostridium difficile].

The results of the studies on the preparation of diagnostic antitoxic sera to C. difficile, intended for use in biological assays with the aim of the laboratory diagnosis of clostridial enteric infections, are presented. The conditions for the detoxification of C. difficile native toxin have been established, the optimum schedules for the immunization of rabbits have been selected and specific antitoxic sera to C. difficile have been obtained. The neutralizing activity of these sera has been evaluated in the lethality test and in the cytotoxic test on human embryo dermo-muscular fibroblast cells M-19.

Animals↗
PubMed1989

[Interferon in rheumatoid arthritis].

The paper is concerned with the role played by interferon (IF) in rheumatoid arthritis (RA). The content of IF was measured in the patients' blood serum and the possibility of the use of the preparations of exogenous interferon for the treatment of RA patients was demonstrated. Assay of serum IF in RA patients showed that its content did not exceed normal. The results of the treatment with IF preparations has demonstrated their beneficial effect on certain parameters. Further study of the role played by IF in the management of rheumatic diseases is required in order to develop the drug doses and schedules for the treatment.

Arthritis, Rheumatoid↗
PubMed1988

[Effect of 5-azacytidine on the frequency of polycentric chromosomes in cells with micronuclei during exposure to 5-bromodeoxyuridine].

Telomeric fusion of metaphase chromosomes was studied in conditions of DNA hypomethylation induced with 5-azacytidine. It was shown that the increased number of dicentric chromosomes was statistically significant in experiments when 5-azacytidine was used together with colcemid and 5-bromodeoxyuridine. These data demonstrate that DNA hypomethylation plays an important role in the manifestation of this phenomenon.

Animals↗
PubMed1988

[Comparative characterization of the morphologic changes induced by the cytotoxic action of a filtrate of Clostridium difficile strain B in cell cultures].

Investigations carried out by the authors have demonstrated the possibility of the simultaneous evaluation of the results of the quantitative and qualitative characterization of the cytotoxic action of the filtrate of C. difficile strain B in the cultures of diploid human cells and cells Fl. The action of the filtrate used in the same dilution (1:1,000) over equal incubation periods (15 minutes) has resulted in the appearance of different morphological changes in each of these cultures. The degree of the manifestation of the cytotoxic action of the filtrate and the consequences of this action depend not only on the dose of the filtrate and the duration of the contact, but also on the kind of cell cultures used in the experiment. The 15-minute contact of human diploid cell culture with the filtrate leads to irreversible lesions of the cells. The rounding of cells Fl, observed during the first 15 minutes of the action of the filtrate, is not fatal for them; in the overwhelming majority of these cells the capacity for proliferation restores at the expiration of a certain period (about 3 weeks), and their adhesive properties increase.

Cell Survival↗
PubMed1988

[5-Chlorodeoxyuridine, more effectively than 5-bromodeoxyuridine, induces the formation of specific dicentric chromosomes in cells with micronuclei].

5-chlorodeoxyuridine (5-ChldU) and 5-bromodeoxyuridine (5-BrdU) were tested in respect of the formation of specific dicentric chromosomes in cells with micronuclei. It is shown that the frequency of dicentrics is higher when 5-ChldU is used. On the ground of results of this study and of the previous data it is concluded that the activity of halogenated deoxyuridines is falling with molecular weight increasing.

Animals↗
PubMed1988

[Enhanced intensity of polycentric chromosome formation in cells with micronuclei exposed to 5-bromodeoxyuridine under prolonged hyperthermia at 40 degrees C].

The formation of polycentric chromosomes in metaphases of the first mitotic division of polykaryocytes containing micronuclei, under 5-BrdU treatment in the condition of a prolonged hyperthermia was studied. It was shown that the enhance of the frequency of polycentric chromosomes at 40 degrees C was statistically reliable. These data propose the existence of an enzymatic mechanism of disrupting the chromosomal ends at mitosis at the optimal condition (37 degrees C). In cells with micronuclei, under 5-BrdU treatment at 40 degrees C, this mechanism undergoes, presumably, a partial inhibition leading to the enhanced frequency of chromosomes with fused telomeres.

Animals↗
PubMed1987

[Combined action of nucleosides and alpha-interferon in inhibiting the reproduction of the herpes simplex type-II virus].

Therapeutic effect of four combinations of antiherpetic chemical preparations--acyclovir (ACV), 9-beta-D-arabinofuranosyladenine (ARA-A) and E-5-(2-bromovinyl)-2'-desoxyuridine (BVDU)--has been studied. Mutual enhancement was observed in all the combinations studied, except for ACV and ARA-A combination, where partial antagonism was observed. ACV + BVDU was shown to be the most optimal combination, with the minimum inhibitory concentration (MIC) of BVDU decreasing 400-fold. A significant enhancement of nucleosides antiviral effect was noted when the human leucocyte interferon was used with the combinations. Along with synergistic effect during the interaction of alpha-interferon with ACV the antagonism in the combination of alpha-interferon with ARA-A was observed.

Acyclovir↗
PubMed1987

Identification of continuous green monkey spleen cell line 455.

Green monkey spleen continuous cell line 455 has been identified by karyologic analysis, by isoenzyme characteristics and electron microscopy. It has been shown that the line 455 consists of green monkey cells; it is not contaminated by other cells from the green monkey, or by other animal or human cells.

Animals↗
PubMed1987

[5-Iododeoxyuridine as well as 5-bromodeoxyuridine induce the formation of specific dicentric chromosomes in cells with micronuclei].

5-iododeoxyuridine used instead of 5-bromodeoxyuridine for the induction of delayed disruption of telomeric links between chromosomes in polykaryocytes consisting of micronuclei was studied. It has been shown that treatment with 5-iododeoxyuridine (20 micrograms/ml) and colcemide (0.1 microgram/ml) for 42 hours induced the dicentric formation. Dicentrics were tested in 27% of all metaphases. This index was lower in comparison with 5-bromodeoxyuridine used for the same purpose.

Animals↗
PubMed1987

[Delayed disruption of the telomeric links between chromosomes in experimentally induced cells with micronuclei exposed to 5-bromodeoxyuridine in the 1st S period after colcemid administration].

Under a long-term administration of colcemid in the Chinese hamster cell culture some cells with micronuclei are seen to form. In the case of co-treatment with colcemid and 5-bromodeoxyuridine (5-BrdU) at metaphases of the first division of cells with micronuclei polycentric chromosomes were observed. These polycentric chromosomes occur due to delayed disruption of telomeric links, previously existing in the interphase. During colcemid treatment the cells pass through two S-periods: one in mononuclear cells, the other in cells with micronuclei. This phenomenon was tested according to the frequency of metaphases with dicentrics after 5-BrdU-treatment of cells at the first or second S-period or during the two cycles of chromosome replication. The 5-BrdU treatment during the first cycle or two cycles of replication resulted in the same frequency of cells with dicentrics--about 50%. The treatment with colcemid alone during two cycles of replication and administration 5-BrdU at the second S-period results in a considerably lower amount (%) of cells with dicentrics--about 10%. Thus, the delayed disruption of telomeric links between chromosomes may occur under the treatment with 5-BrdU at the first S-period after colcemid administration. It is also concluded that this phenomenon can be reproduced in cell with micronuclei when 5-BrdU is incorporated differentially in the sister chromatids.

Animals↗
PubMed1987

[Determination of the biological activity of Clostridium difficile toxins in in vivo and in vitro experiments].

The biological activity of the filtrates of 29 C. difficile strains was studied in vivo (suckling white mice) and in vitro (cell cultures of different species and origin). The action of the filtrates on the experimental models in vivo was evaluated from the cytotoxic effect index, while in vitro the intensity of the cytotoxic effect was evaluated from the percentage of dead cells in the monolayer. The results of the comparative determination of toxicity characteristics in vivo and in vitro demonstrated that cell cultures were more sensitive experimental models than suckling white mice. The use of cell cultures permitted the quantitative evaluation of the cytotoxic activity of the filtrates under study, as well as the detection of their cell-directed action at minimal concentrations.

Animals↗
PubMed1987

[Behavior of the nucleolus organizer regions of the chromosomes in polykaryocytes consisting of micronuclei].

The nucleolar organizer regions (NORs) of Chinese hamster chromosomes (clone 237, cell line BIId-ii-FAF28) were studied in mononuclear cells and polykaryocytes induced with colcemid. The chromosomes with NORs were marked as 1, 2, 3, 4. The activity of NORs in mononuclear cells was higher in chromosomes 1, 2, 3. The associations of NORs were observed between chromosomes I and 2 (3% of all metaphases). In polykaryocytes the chromosomal pairs 1, 2, 3 showed different NOR activity in different metaphases. The associations of NORs in pairs of chromosome I were found in 51.3% of cases. The associations of NORs in pairs of chromosome 2 were observed in 7.5% of cases. This method may be used for the estimation of association potency of NORs in chromosomes.

Animals↗
PubMed1986

Characterization of the continuous green monkey spleen cell line 455.

A continuous line of adult green monkey spleen cells has been established and designated 455 (according to the number of animal). Cell suspension for primary explantation has been prepared by perfusion and disaggregation of the organ. The obtained culture, which consisted of fibroblast-like cells with chromosome modal number 60, underwent 25 passages followed by ageing and death (line 455 D). At passage level 13 in 2 culture flasks with 455 D cells, islets of polygonal cells had developed within 35 days; they gave rise to a continuous cell line with chromosome modal number 110 (designated line 455). Line 455 has a high proliferative activity but low demands on the composition of culture media and it can be easily passaged with the bovine serum at concentration of 1-5%. It is highly sensitive to a number of viruses. It is not contaminated with bacteria, fungi, mycoplasmas or viruses, it does not have a tumourigenic activity. Hence, it is a promising cellular model for virological studies, in particular, for preparation of inactivated vaccines along with Vero and 4647 cells. The line 455 can be used for investigation of the problems of haemopoiesis and immunogenesis.

Animals↗
PubMed1986

[Use of a diploid cell line for detecting the toxic components in medical immunobiological preparations].

Besides specific antigens medical immunobiological agents (MIBA) contain chemical compounds (formaldehyde, aluminium hydroxide and mercury salt, merthiolate) in permissible concentrations. Therefore, the investigation of MIBA and their components should involve methods studying the effect of chemical compounds on cells and their structural components. For this purpose WHO recommends to use cell cultures. The results obtained show that cell cultures (constant and diploid lines) allow the differentiation in the degree of toxicity of chemical compounds constituting MIBA. Merthiolate had the strongest irreversible lethal effect. The technique can prove useful for more accurate evaluation of toxicity in inactivated bacterial and viral vaccines as well as in serum preparations. Cell culture can be successfully used for the detection of toxic components in vaccines and serum drugs, with the final safety tested by their injection to animals.

Aluminum Hydroxide↗