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Biomedical subjects

G M Volgareva

Publications and source records attributed to G M Volgareva.

At least 19 recordsLinked to original sources

The influence of two carotenoid food dyes on clastogenic activities of cyclophosphamide and dioxidine in mice.

The influence of the food dyes E160e (beta-apo-8'-carotenal in an oil suspension) and E160a (beta-carotene in an oil suspension) on clastogenic effects of cyclophosphamide (CP) and dioxidine (DN) was investigated. Chromosome damage in the bone marrow of C57BL/6 mice was reported. The following protocols were used: (1) simultaneous single administration of the dye and the mutagen and the subsequent animal sacrifice within 24 hr; (2) a 4-day pretreatment with the dye (daily administrations) followed with simultaneous injection of the dye and the mutagen on the 5th day 24 hr before sacrifice; (3) daily co-administration of the dye and the mutagen for 5 days with sacrifice 6 hr after the last administration. CP at a dose of 30 mg/kg and DN at 300 mg/kg were injected intraperitoneally; the dyes at doses of 0.5, 5 and 50 mg/kg were given orally. Under all the protocols applied, E160e at a dose of 50 mg/kg caused a significant reduction of both DN and CP effects. At 5 mg/kg this dye reduced the effects of the mutagens only under the pretreatment regimen. Pretreatment with E160a at doses of 5 and 50 mg/kg resulted in a meaningful reduction of the DN effect. Under the combined treatment with mutagens this dye reduced both CP and DN effects.

Animals↗

[Genotoxicity of vaccines: an unresolved problem of ecological genetics].

The problem of potential remote consequences of vaccinations still remains to be solved. Data on the effects of immunobiological preparations, including vaccines, employed for preventive mass immunization on certain hereditary structures are reviewed. Many of these preparations are genotoxic. Prospects for diminishing the genetic risks of vaccinations are discussed.

Ecology↗

[Control of genetic consequences of vaccinations: electron microscopic analysis of murine synaptonemal complexes].

The ability of two inactivated bacterial vaccines, from Proteus vulgaris and Klebsiella pneumoniae, to injure synaptonemal complexes (SCs) was studied by means of electron microscopy. The preparations were given intraperitoneally to C57BL/6J male mice during five successive days and testes were fixed 24 h after the last injection. Cyclophosphamide was used for positive control. The vaccine from Klebsiella given at subtoxic dose, which was about 200 times higher that that given to people during vaccinations, induced the 10-fold rise in the frequency of SC abnormalities in murine 1-storger spermatocytes. Breaks of SCs and of single lateral elements of SCs predominated over other types of vaccine-induced anomalies. According to the preliminary data, vaccine from Proteus at subtoxic dose showed no damaging SC activity. The results of the given study are discussed in connection with the negative data obtained earlier when genotoxicity of these two vaccines had been studied in the Ames test, in routine investigations of bone marrow metaphases of vaccinated mice as well as under light microscopy of their SCs.

Animals↗

[The chromosome-damaging action of 2 chemical vaccine contaminants on mice].

The cytogenetic effects of two chemical agents, hydroxylamine used for the destruction of bacterial cells and thimerosal added to many immunobiological preparations as preservative, were studied in vivo by their action on the marrow cells of C57BL/6J mice. The preparations under study, when injected intraperitoneally in a wide range of doses, including subtoxic ones, induced no chromosomal aberrations. At the same time cyclophosphamide, an antitumor cytostatic agent used for positive control, produced a pronounced damaging effect on chromosomes.

Animals↗

[The mutagenicity of a new multicomponent vaccine made from the antigens of Klebsiella pneumoniae, Staphylococcus aureus, Proteus vulgaris and Escherichia coli].

Inactivated bacterial vaccine, containing K. pneumoniae, S. aureus, P. vulgaris and E. coli antigenic complexes were tested for mutagenicity in the test described by Ames et al. and in vivo, in experiments on mice. In Salmonella typhimurium cells, strain TA-98 and TA-100, the preparation (5-75 mg/ml) did not increase the frequency of reversions and histidine-independence either in direct experiments or after metabolic activation with rat liver homogenate. In experiments on mice the vaccine (3.3 mg/kg and 33 mg/kg) did not induce chromosomal anomalies in spermatogonia. In all experiments the mutagens used for positive control produced a mutagenic effect.

Animals↗

[The protective activity of polyclonal and monoclonal antibodies to the lipopolysaccharide of Neisseria meningitidis serogroup A in in vivo experiments].

The protective activity of the sera of mice immunized with the preparations of native and detoxified N. meningitidis lipopolysaccharide (LPS), group A, as well as with monoclonal antibodies to N. meningitidis antigens, groups A and B, was studied on the mucin model of meningococcal infection. The study showed that the maximum level of anti-LPS antibodies in mice was observed on day 7 after the injection of LPS. Immune sera obtained from mice were capable of protecting the animals from fetal meningococcemia induced by N. meningitidis strains of homologous and heterologous groups. As shown by the results of this study, the alkaline treatment of N. meningitidis native LPS did not decrease the protective properties of antibodies. The monoclonal antibodies under study were found to possess high preventive activity in mice challenged with N. meningitidis, groups A and B. Anti-LPS monoclonal antibodies showed greater protective activity than antipolysaccharide monoclonal antibodies.

Animals↗

[Control of the mutagenicity of a new immunomodulator].

New immunostimulator STP, peptide isolated from the cultivation medium of Streptococcus species producer strain TOM-1606 by chromatographic purification, was controlled for mutagenicity. The preparation, introduced into mice in doses of 6.7 X 10(2) - 6.7 X 10(4) micrograms/kg, i.e. exceeding the stimulating dose 1000-fold, did not induce the appearance of micronuclei in polychromatophilic erythrocytes of the marrow, the fixation of the material being made 24, 48 and 72 hours after the injection. In Ames' test on Salmonella typhimurium strains TA 98 and TA 100 neither native STP, nor STP activated with the microsomal fraction of rat liver enzymes did not increase the frequency of reversions to histidine independence. The absence of mutagenic properties in STP was demonstrated by the parallel pronounced genotoxic action of a number of known mutagens used as positive controls.

Adjuvants, Immunologic↗

[The natural background of chromosome anomalies in the bone marrow cells of mice and the control of vaccines for genotoxicity].

The levels of chromosomal anomalies in marrow cells of mice kept under conventional conditions in the animal house of the Mechnikov Research Institute for Vaccines and Sera (Moscow) and under specific pathogen-free conditions were compared by the micronuclear and metaphasic methods. In the animals kept under specific pathogen-free conditions the occurrence of anomalies did not exceed the normal level; in the animals of the other group the level of cells with aberrations was 4-5 times higher. All detected aberrations in the chromosomal structure were unstable. The results obtained in this investigation indicate that under the conventional conditions existing in the animal house of a microbiological research institute mitogens of the biological nature may be present.

Animals↗

[Cytogenetic control over the safety of merthiolate].

The capacity of merthiolate (also known as thimerosal), a mercury organic compound used as preservative in vaccines, to induce chromosomal aberrations was studied in vivo in experiments on mice. The metaphasic method of the registration of anomalies was used. In a dose of 3.3 micrograms/kg body weight merthiolate did not produce a damaging effect on the chromosomes of marrow, spleen and embryonal liver cells. Cyclophosphamide (in a dose of 25-50 micrograms/kg) used as positive control induced a significant rise in the frequency of chromosomal transformations.

Animals↗

[The safety of a vaccinal preparation made of bacteria of the genus Proteus: the absence of a mutagenic effect].

The protein-lipopolysaccharide vaccinal preparation, obtained by the disintegration of microorganisms of the genus Proteus by means of hydrochloric hydroxylamine, has been tested for mutagenicity. Two tests have been used: (1) the count of reversion to histamine-dependence in Salmonella typhimurium cells, strains TA-98 and TA-100, intended for detecting mutations, such as read-through frame shift and, respectively, the change of nitrous bases in DNA; and (2) the count of structural aberrations in chromosomes and numeric karyotype changes on metaphase plates from the marrow of mice. In some of the tests the vaccine has shown mutagenic properties.

Animals↗

[Comparative study of murine B-cells obtained by 2 different methods proliferating long-term in vitro].

The hybridization of myeloma cells NP with lymphocytes of mice, immunized with protein isolated from Neisseria meningitidis strain Bc5 in a single injection into the spleen 3 days prior to fusion, made it possible to obtain 25-72% of hybridomas secreting antibodies to meningococcal antigens. The treatment of immune lymphocytes from these mice with the total preparations of nucleic acids, isolated by the phenol-detergent method from mouse myeloma cells NP and NS/0, induced an increase in the proliferative activity of lymphocytes; in some microcultures multilayer cell growth was observed on the bottom of the wells, whereas in the control microcultures such growth was absent. No synthesis of specific antibodies was detected in the cultures of lymphocytes whose proliferation was stimulated with nucleic acids.

Animals↗

[Problems in maintaining hybridomas in vivo].

The literature data on the regularities of the manifestation of tumorigenic capacity in somatic hybrids, on the correlation of this sign with the features of the in vitro transformation of hybrid cells, on the chromosomal stability and taking capacity of hybridomas have been analyzed. The expediency of the inoculation of animals with hybridomas, made considerably earlier than required by the traditional scheme of obtaining monoclonal antibodies, with a view to the selection of tumorigenic hybridoma variants is suggested. The aims of the experimental work have been determined.

Animals↗

[Cultivation of murine B-cell hybridomas in the spleen].

The tumorigenic capacity of mouse B-cell hybridomas in both cloned and primary cultures was studied. The cells were selected for inoculation from 24-well plates and introduced into the spleen of syngeneic mice. The cells took in 50% of the animals. The cells of hybridoma tumors induced as the result of intrasplenic inoculation, when subcultured in the second passage following the standard scheme, i.e. inoculated intraperitoneally in a dose of 1 X 10(7) cells into mice previously treated with vaseline oil or pristane, produced tumors in 100% of the animals.

Animals↗

[Chromosome markers of murine hybridomas].

The karyological study of 10 mouse hybridomas revealed that all cells in two hybridoma clones, as well as in two subclones isolated from the third hybridoma, contained specific clonal biarmed markers, atypical for myeloma parent cells X63.Ag8.653. The proportion of cells with additional new meta- and submetacentric markers, which were different in the cells of the same culture, reached 0.38-0.56 in some of the hybridomas under study. The above biarmed chromosomes were, probably, formed as the result of the centromeric fusions of subtelocentrics. The presence of identical new biarmed chromosomes in all cells in some hybridoma cultures could be attributed to the fact that all these cells originated from a single initial cell, already containing such marker (or markers). The results of the cytogenetic analysis may confirm the monoclonal origin of a considerable part of mouse hybridomas.

Animals↗

[Mycoplasma infection as a possible cause of hybridoma instability].

Cytogenetic analysis of mouse hybridoma producing monoclonal antibodies to diphtheria toxin and of its derivative, that lost secretory activity at the third passage in vivo, has been carried out. 58% cells of antibody secreting cell lines belonged to a modal class (76-79 chromosomes per cll). The modal chromosomal number of the subline that has stopped producing antibodies decreased to 63-66 per cell and the stem line of this derivative consisted of 30% of cell population only. Chromosome aberrations were much more frequent in hybridoma cells, that ceased to secrete antibodies, than in cells of original hybridoma: 32.3% of aberrant metaphases (1.38 break per cell) and 6.3% of aberrant metaphases (0.1 break per cell), respectively. Mycoplasma infection was found in the hybridoma subline that stopped producing antibodies as defined by the microbiological and cytochemical techniques. Mice might be the possible source of infection. By means of cloning of hybridoma variant, that did not secrete immunoglobulins, several sublines with the recovered secretory function were obtained.

Animals↗

[Karyologic research on murine B-cell hybridomas].

Karyotypes of 10 murine hybridomas producing monoclonal antibodies to microbal antigenes were examined using chromosome slides stained with Azur-eosine. Hybrid origin of all the cell clones was confirmed. The cultures differed from each other in modal chromosome numbers, in novel markers that were absent from cells of the parental myeloma X63.Ag8.653, in the frequency of metaphases with double minute chromosomes and in the level of cells with chromosome aberrations. The results obtained enable us to recommend a cytogenetic analysis for the identification of hybridomas. The following observations point out to a relative instability of the chromosomal apparatus of hybridomas: chromosome numbers varied significantly from cell to cell within one and the same clone; modal chromosome counts decreased in 3 of 5 hybridomas that were studied repeatedly within 1-2 months; in some hybridomas unstable chromosome aberrations were found in 18-38% of cells.

Animals↗

[Effect of polyploidization on the anchorage-independent multiplication of transformed cells].

Three nearhexaploid sublines were obtained from hypotriploid mouse L cells by means of colcemid treatment. When cultivated on solid substratum, all of them did not differ from the parental line either in doubling time or in cloning efficiency. The ability of polyploid cell variants to be initiated for proliferation in a semi-solid medium was equal to that of hypotriploid cells, while the average diameter of colonies formed by hexaploid cells in methyl cellulose turned out to be significantly smaller than the size of colonies of parental cells. The inhibition of growth in the semi-solid medium may reflect partial normalization of the transformed phenotype of polyploid L cells.

Animals↗