Genotoxicity of single-walled carbon nanotubes: in vitro study on human embryonic fibroblast cells.

The effects of single-walled carbon nanotubes on the levels of DNA aberrations, chromosome and genome disorders were studied on human embryonic fibroblasts, their karyotype was analyzed by the spectral karyotyping method. The level of DNA aberrations increased after 3-h exposure to the nanotubes. No appreciable increase in the incidence of aberrant metaphases, micronuclei, and chromosome 1, 6, 8, 11, X, and Y aneuploidy after 24- and 48-h incubation with the nanotubes were detected.

[Genetic safety of cellular therapy].

This paper presents the main results of the study on chromosome and genome variability of mesenchymal stem cell cultures from bone marrow and adipose tissue carried out in the Laboratory of Mutagenesis, Research Centre for Medical Genetics, over the last three years. Genome stability was assessed from DNA damage using the DNA comet assay, karyotyping and registration of aneuploidy by the FISH method. We found that DNA damage rate in MSC cultures from bone marrow was 3.9% and 3.8% at the early (2-5) passages and the late (10-15) passages respectively. The cultures were characterized by high dispersion of individual values. Karyotyping showed mosaicism in both types of MSC cultures at the early and late stages of cultivation. The fraction of abnormal cells in some cultures amounted to 80-90%. Evaluation of aneuploidy in interphase cells revealed 1.34% of aneuploid cells (on the average) per one "conventional" chromosome; their overall frequency in the genome amounted to 20-40%. The frequency of aneuploid cells was similar at the early and late passages. Cultures with clones of trisomic and monosomic cells were revealed. The probability of occurrence of abnormal cells may increase by virtue of de novo mutations in the culture and as a result of positive selection of the cells existing in the organism that exhibit a higher reproduction rate in culture. Based on the experimental data on mutational process, selection of mutant cells and clone formation, it is concluded that cytogenetic control of stem cells is necessary to ensure the safety of cellular therapy.

Study of genetic stability of human bone marrow multipotent mesenchymal stromal cells.

Immunophenotype, proliferation rate, and genetic stability parameters of bone marrow multipotent mesenchymal stromal cells were studied. Despite the reduction of proliferative activity by passages 11-12, the cells retained the characteristic immunophenotype. The incidence of spontaneous aneuploidy for autosomes 6, 8, 11 and sex chromosomes was evaluated. Two cultures of mesenchymal stromal cells carrying aneuploid cell clones were detected: with chromosome 8 trisomy and X chromosome monosomy. The results indicate the possibility of genetic transformation and selection of mesenchymal stromal cells with abnormal karyotype during in vitro culturing.

Spontaneous aneuploidy and clone formation in adipose tissue stem cells during different periods of culturing.

Cytogenetic analysis of 13 mesenchymal stem cell cultures isolated from normal human adipose tissue was carried out at different stages of culturing. The incidence of chromosomes 6, 8, 11, and X aneuploidy and polyploidy was studied by fluorescent in situ hybridization. During the early passages, monosomal cells were more often detected than trisomal ones. A clone with chromosome 6 monosomy was detected in three cultures during late passages.

Chromosome variability of human multipotent mesenchymal stromal cells.

We elaborated a method of preparing cytogenetic preparations of cultured multipotent mesenchymal stromal cells from the adipose tissue. It was found that karyotypic changes (monosomy, translocations) appear in some samples during culturing. Clones with changed karyotype were detected in 11-14-passage cultures from 2 of 7 individuals. The percent of aberrant cells in cultures from different individuals varied from 1.5 to 5.95 per 100 cells, which attested to karyotype instability. These data substantiate the need for cytogenetic control of cells before their transplantation into donor organism and further investigation of chromosome variability in stem cells.

Phytoadaptogen correction of clinical and immunobiological parameters in patients with benign prostatic hyperplasia.

Correction of hormonal, immune, interferon, and antioxidant status and genetic abnormalities with a complex phytoadaptogen leads to positive clinical effects in elderly patients with benign prostatic hyperplasia.

Effects of vitamin supply on spontaneous and chemically induced mutagenesis in human cells.

Chromosome aberrations in donor peripheral blood lymphocyte culture were evaluated before, 14 and 30 days after treatment with a vitamin/mineral complex. Treatment with the complex had no effect on spontaneous level of aberrant cells. The number of chromosome aberrations induced by dioxidine or cadmium chloride in vitro at the G2 stage decreased on days 14 and 30 of treatment with the complex.

[Periodic variations of spontaneous chromosome aberration rate in human blood lymphocytes ]. / Vremennye kolebaniia spontannogo urovnia khromosomnykh aberratsii v kul'ture limfotsitov perifericheskoi krovi cheloveka.

Spontaneous chromosome aberration rate in human blood lymphocytes was studied using the data collected during 30 years. Seasonal variation was found. An absolute maximum of chromosome aberration rate was observed in winter and a local maximum, in summer. In spring and autumn, this value decreased. There was a statistically significant trend towards higher frequencies of aberrant metaphases during the period studied. A periodic pattern of changes in the chromosome aberration frequency was found. The data fitted a sinusoid with a period of 4.5 years.

[The database for analysis of quantitative characteristics of chromosome aberration frequencies in the culture of human peripheral blood lymphocytes]. / Baza dannykh dlia analiza kolichestvennykh kharakteristik chastoty khromosomnykh aberratsii v kul'ture limfotsitov perifericheskoi krovi cheloveka.

The data on spontaneous chromosome aberration rates in cultures of human peripheral blood lymphocytes obtained in the past 30 years have been collected to form a database. The database contains the results of analysis of more than 330,000 metaphases in lymphocytes from more than 1200 subjects. The frequency of aberrant metaphases in the control group has been estimated at 0.0213 +/- 0.00085. No differences between sexes have been found with respect to either the total chromosome aberration rate or the rates of individual aberration types. The total chromosome aberration rate did not depend on age; however, it has been found that the number of fragments increased and the number of exchanges decreased with age. Smoking has been found to increase the frequency of chromosome aberrations in individuals with occupational hazards, but not in those who are not occupationally exposed to radiation or chemicals. Alcohol consumption increased the frequency of paired fragments, whereas the frequencies of other aberrations did not differ from the control values.

[Dioxins and medical-genetic indices of health of residents of the town of Chapayevsk]. / Dioksiny i mediko-geneticheskie pokazateli zdorov'ia naseleniia goroda Chapaevska.

The paper presents the results of an integrated medical genetic survey carried out in the town of Chapayevsk. The survey included an estimation of the incidence of congenital malformations (CMF), congenital morphogenetic options (CMGO), evaluation of the frequency of chromosomal mutations of various types and micronuclei in human somatic cells. The incidence of CMF among newborn infants corresponds to that in Russia, but such forms of CMF as congenital hydrocephalus and agenesia and disgenesis of the kidney were more common in the town. The study ascertained that the average number of CMGO per child was on the increase. Cytogenetic findings unambiguously demonstrate that there was a spatial gradient within the town (from the plant to remote districts), higher rates of chromosomal aberrations. Further studies of the effects of dioxins on genetic health are required to assess the actual genetic risk due to its human contact.

[Unusually high level of chromosome variability in cultured human peripheral blood lymphocytes]. / Neobychaino vysokii uroven' khromosomnoi izmenchivosti v kul'ture limfotsitov perifericheskoi krovi cheloveka.

A cytogenetic examination carried out in the inhabitants of Seversk (Tomsk oblast) and workers of the Siberian chemical industrial complex (a complex of nuclear-chemical and fuel plants), living in the same town, revealed unusually high level of spontaneous chromosomal variability both in control and industrial groups (total irradiation doses 1.8 to 3.7 and 9.3 to 15.7 Gy, respectively). The frequencies of cells with chromosomal aberrations (estimated per 100 cells) in control and industrial groups were 4.69, 6.04, and 6.64, respectively, and the total number of aberrations constituted 6.93, 8.47 and 12.06, respectively. These frequencies were several times higher compared to the summarized literature data on the control levels. The high average aberration level was caused by the elevated proportion of chromatid-type aberrations and paired fragments. The reasons for this are unclear. The levels of radioactive background and chemical air pollution in the town were not increased.

[Delayed cytogenetics effects of chronic irradiation of South Ural population]. / Otdalennye tsitogeneticheskie éffekty khronicheskogo oblucheniia naseleniia Iuzhnogo Urala.

The evaluation of remote cytogenetic consequences was studied in population, irradiated at low level during 40 years and more preferentially internally. Mean level of exposure was in 1950 year at maximum--0.2 Sv/year. In 1993 year it was equal 1.95 mSv/year. It was revealed statistically significant increasing of chromosome type of aberrations in lymphocytes of irradiated people in comparison with control ones. The incidence of chromosome type exchanges in irradiated individuals comprised 0.43 per 100 cells, and 0.17 per 100 cells in the control.

[Inhomogeneity of control samples as the reason for additional variations in the spontaneous level of chromosome aberrations in a human lymphocyte culture]. / Neodnorodnost' kontrol'nykh vyborok kak prichina dopolnitel'nykh variatsii spontannogo urovnia khromosomnykh aberatsii v kul'ture limfotsitov cheloveka.

The results of population cytogenetic studies performed by a standard technique in one laboratory during 1987-1992 are summarized. Variations in the rate of spontaneous chromosomal aberrations were found in lymphocyte culture derived from individuals employed in the nonindustrial sphere and in the administrative sector of the chemical industry. The proportion of cells with chromosomal aberrations is 1.56 +/- 0.10% in the first group and 2.78 +/- 0.15% in the second one. The ratio of types of aberration is similar in both groups. No differences were observed in the rate of spontaneous chromosomal aberrations as related to the extent of chemical pollution of place of residence.

Analysis of multiaberrant cells in lymphocytes of persons living in different ecological regions.

An analysis was carried out of multiaberrant ("rogue") cells in lymphocytes of persons living in unpolluted areas (controls), and in areas chemically or radioactively (Chernobyl fall-out) polluted. The total number of analysed cells was 102,391, among these 10 cells with three and more aberrations were found. These multiaberrant cells occur in persons of both sexes and various ages living in regions with a moderate degree of mutagenic exposure. The main types of aberrations in multiaberrant cells were chromosome exchanges, accompanied by double fragments.

[Cytogenetic screening of workers of rubber manufacturing industry]. / Tsitogeneticheskoe obsledovanie rabochikh proizvodstva reziny.

Cytogenetic analysis of lymphocytes was performed in 36 preparatory workers engaged into rubber shoes and general mechanical rubber goods production. Preparatory workers and management staff had the same chromosomal aberrations frequency. Although chromosomal aberrations frequency in employees of the enterprise appeared to be twice as much as that for general population, which proves hazardous factors of rubber production to afflict genofond of employees.

[Genetic monitoring of human population exposed to chemical and radiation hazards]. / Geneticheskii monitoring populiatsii cheloveka pri real'nykh khimicheskikh i radiotsionnykh nagruzkakh.

It is impossible to protect human heredity from the ecological consequences of environmental pollution if there is no permanent control of hereditary variability in human populations, i.e. genetic monitoring. One of the urgent problems in genetic monitoring planning is the magnitude of representative samples necessary for establishing the significant mutation effect of environmental factors. The elevation of the mutation frequency can be determined either by the dynamics of the frequencies of hereditary pathology or by comparison of the frequencies in populations that differ in harmful factor exposures. Comparison of the effects evaluated by cytogenetic, epidemiological (registration of congenital malformation frequencies) and molecular-genetic methods in various population groups will make it possible to solve the problem of safety in the investigated regions.

[Cytogenetic examination of workers engaged in manufacturing of asbestos technical products]. / Tsitogeneticheskoe obsledovanie rabochikh proizvodstva asbesto-tekhnicheskikh izdelii.

The article contains data on a cytogenetic monitoring of workers engaged in asbestos production, depending on duration of professional service and degrees of dust contamination of the air. The results of the cytogenetic analysis of the peripheral blood lymphocytes in 31 workers revealed the average rate of aberrant cells 1.78% in workers with professional service below 1.5 years, 2.43%--with more than 10 years of service, 2.72%--in the control group (the personnel not engaged in the production). The differences were statistically negligible.