Frequency Of Metaphases Research Articles

An efficient and simple method for enriching metaphase cells for dicentric chromosome assay.

As compared to peripheral blood mononuclear cell (PBMC) culture, a lower mitotic index (MI) is seen in whole blood (WB) culture, but WB can be directly used for culture in dicentric chromosome assay (DCA). The purpose of this study is to develop a simple protocol for metaphase enrichment to improve the metaphase frequency of WB culture. Fixed cells were obtained after performing WB and PBMC cultures for DCA after conventional fixation. An additional low-speed centrifugation of 200×g for 1min was performed, separating the fixed cells of WB culture into a pellet and a supernatant fraction. The additional low-speed centrifugation enriched metaphase frequency and provided an MI comparable to the PBMC culture in the pellet fraction. Our study suggests that it is possible to increase the number of metaphase cells on slides using the slow centrifugation method, which could contribute to the efficiency of chromosome aberration analysis in biodosimetry.

Characteristics of the karyotype of Ukrainian buffalos

The article presents the results of studying the karyotype of the Ukrainian buffalo population. With the help of routine and GTG methods of analysis of metaphase plates of chromosomes, it was established that in the studied animals the diploid chromosome set was equal to fifty chromosomes (2n=50), which consisted of 5 pairs of meta- and submetacentric and 19 pairs of acrocentric autosomes and one pair (XX) or (XY) sex chromosomes. The total number of chromosome arms (FN) was 60, which correspond to animals of the water buffalo species (Bubalus bubalis), a subspecies of the river buffalo (B. b. Bubalis). Cytogenetic control revealed wide intraspecies limits of spontaneous somatic mutagenesis: absence of constitutive chromosomal disorders; the frequency of metaphases with aneuploidy, the average value (M±m) of which was equal to 10.5±0.13%, polyploidy (M±m=0.7±0.25%), asynchronous separation of the centromeric regions of chromosomes - (M±m=5.3±2.00), chromosomal breaks (M±m=0.7±0.24%), the proportion of cells with micronuclei (M±m=2.5±0.39‰), binucleated cells (M±m=2.6±0.32‰) and mitotic index (M±m=4.8±0.65‰). It has been established that Ukrainian river buffaloes are characterized by high karyotype stability.

The Boosting Effects of Melatonin on the In Vitro Fertilization (IVF) of Women with Polycystic Ovary Syndrome.

Polycystic ovary syndrome (PCOS) is one of the most critical disorders, which affects approximately 20% of women of childbearing age and melatonin supplementation in these women can be effective. However, human studies in this area are particularly limited to IVF candidates. The aim of this clinical trial study was to evaluate the effect of melatonin on the in vitro fertilization (IVF) in PCOS involved women. In this clinical trial study, a total of 320 women with PCOS were randomly assigned to the intervention and control groups. Patients in the intervention group (n=160) received a combination of melatonin and metformin (3 mg and 500 mg, respectively) three times a day. The control group (n=160) received metformin 500 mg from the luteal phase of the cycle before the start of gonadotropin. Oocyte and embryo quality, number of oocytes, and pregnancy outcomes were compared in both groups. Our study revealed that the frequency of Metaphase II oocytes (69.9% vs. 57.9%, p<0.001) and the number of embryos of the top-quality (grade A) were higher in the group treated with melatonin (40.3% vs. 29.9%, p=0.001). The rate of clinical pregnancy and implantation were also higher in the intervention group. The odds of clinical pregnancy in the intervention group was 1.8 times (p=0.039). Moreover, oral melatonin supplementation was effective in patients with PCOS, who were candidates for IVF because of the increased quality of mature oocytes, top-quality embryos, and increased odds of clinical pregnancy.

Mitotic index maximization with no effect on radiation-induced dicentric chromosome frequency

Purpose The dicentric chromosome (Dic) assay, which is the gold standard for biological dose assessment in radiation emergency medicine, requires an analysis of at least 500 lymphocyte metaphases or 100 Dic aberrations. Therefore, peripheral blood culture conditions able to obtain a high frequency of metaphases for efficient dose evaluation should be optimized. However, the type of blood cultures [i.e. whole blood (WB) or isolated peripheral blood mononuclear cell (PBMC)-culture] and blood volume differ between biodosimetry laboratories. The purpose of this study is to investigate the blood volume at which a high mitotic index (MI) is obtained in peripheral WB-culture and isolated PBMC-culture, and to examine the possible effect of blood volume on radiation-induced Dic frequency. Materials and methods Peripheral blood was collected from three healthy donors with their informed consent. The complete and differential blood counts were performed using an automated hematology analyzer. After blood count, peripheral blood was irradiated with 0 or 2 Gy X-ray. Blood was cultured with phytohemagglutinin (180 μg/ml) and demecolcine (0.05 μg/ml) for 48 h. The MI and Dic frequency were analyzed in 5, 10, 15, 20, 25, and 30% WB-cultures and 0.6, 1.2, 1.8, 2.4, 3.0, 3.6, and 4.2 ml WB-equivalent PBMC-cultures. Results In WB-culture, MI showed the highest value (∼22%) in 5–15% WB-culture and then gradually decreased to ∼9% with 30% WB-culture. MI peaked at 36 and 31% in 1.8 and 2.4 ml-WB equivalent volumes for PMBC-cultures, respectively. MI progressively decreased as the amount of PBMCs increased. Although individual differences were observed in the MI values among the three subjects, all the subjects showed the same tendency and higher MI was seen in PBMC than WB-cultures. However, these factors had no significant impact on the yield of Dics. In all culture conditions, the estimated dose calculated based on the Dic frequency was equivalent to the absorbed dose of ex vivo X-ray-irradiated blood. Conclusion While MI was affected by the blood culture type and the volume of cultured blood, Dic yield did not differ significantly between these conditions. These results could be used by relevant laboratories to optimize MI in certain circumstances.

Polymorphism of TGF-β1, TР53, CHEK2, ATM genes аnd chromosomal aberrations in workers at coal thermal electric power station

Introduction. Working conditions at coal-fired power plants cause an increased risk of the formation of chromosomal damage in workers. The contribution of the variability of the structure of the genes controlling the cell cycle and apoptosis to the occurrence of cytogenetic disorders induced by such mutagens has been little studied. Material and methods. The polymorphic variants of the genes: TP53 (rs1042522), CHEK2 (rs555607708), ATM (rs1801516), TGF-β1 (rs1800469), and the level of chromosomal aberrations (CA) in the lymphocytes of the blood were studied. Three hundred twenty-six workers of coal-fired power plants and 267 individuals who did not work in industrial enterprises were examined. All individuals were Caucasians, residents of Kemerovo (Western Siberia, Russia). Results. The level of CA in blood lymphocytes in thermal power plant workers was established to be statistically significantly higher than that of residents of the same locality who never works in industrial enterprises (3.05 ± 0.09% versus 1.67 ± 0.07%, p = 0, 000001). The prevalence of the polymorphic variants of the TP53 (rs1042522), CHEK2 (rs555607708), ATM (rs1801516), TGF-β1 (rs1800469) genes in the group of workers was the same to those in the comparison group and corresponded to the global data obtained in Caucasians. In the group of workers with the TT genotype of the TGF-β1 gene, the frequency of metaphases with chromosome damage was statistically significantly higher than in individuals with the CC genotype (4.07 ± 0.41% versus 2.85 ± 0.10%, p = 0.006). Discussion. For the first time a significant contribution of polymorphic variants of TGF-β1 genes to the formation of chromosomal damage in working coal-fired power plants was revealed. This may be associated with an increased level of expression of the multifunctional cytokine TGF-β1 in owners of the TT genotype and its ability to influence proliferation, apoptosis, telomerase activity, and other critical cellular processes. Conclusion. The results of the study I, ndicate that not only the complex of industrial genotoxicants, but also individual genetic characteristics of the organism can influence on the formation of cytogenetic disorders in workers at thermal power plants.

Chromosomal aberrations in coal mine workers with lung diseases

Introduction. It is known that despite the achievements of modern science and technology and the introduction of modern safe technologies in coal mining enterprises, working in coal mines remains one of the most dangerous for health. It is established that one of the most important and signifi cant causes of occupational diseases in miners is respiratory pathology. Miners working in underground conditions are exposed to a long-term set of harmful physical and chemical factors that contribute not only to increasing the risk of various chronic occupational diseases, but also to genotoxic risk. Accounting for chromosomal aberrations is one of the most highly sensitive methods of biological indication, which allows us to assess the General patterns and specifi cs of the impact of genotoxic exposure. The aim of the study is to conduct a chromosomal analysis of somatic cells of workers of Kuzbass coal mines who are suffering from occupational pulmonary pathologies. Materials and methods. To assess the genotoxic impact of the production environment of coal mines, a cytogenetic analysis of chromosomal aberrations in the blood lymphocytes of 169 miners with lung diseases was performed. Of these, 93 people were diagnosed with “chronic dust bronchitis”, and 76 people — “anthracosilicosis”. For comparison, we used data from cytogenetic analysis of 376 conditionally healthy miners, without signs of lung diseases. As a control, 250 male individuals who did not work in industrial enterprises were studied. The material for the study was whole peripheral blood. Blood cells were cultured using a standard semi-micrometer method. The proportion of aberrant metaphases was determined by calculating the frequency of metaphases with chromosome aberrations (as a percentage of the studied number of cells). Results. It was found that the frequency of chromosome aberrations in the group of miners with lung diseases (5.04±2.40%) and healthy miners (4.12±2.32%) was signifi cantly higher than in the group of individuals who did not work in production (1.78±1.26%, p &lt;0.00001). There was a signifi cant increase in aberrant cells, single fragments, and chromatid-type aberrations in miners with pulmonary pathologies compared to healthy miners. Conclusions. The results of the study indicate a high genotoxic hazard of working conditions in coal mines. Chronic lung diseases in miners caused by prolonged contact with production factors are accompanied by a statistically signifi cant increase in chromosomal instability in peripheral blood lymphocytes. The highest values of the frequency of chromosomal abnormalities were recorded in miners performing basic production operations. Data were obtained on the modifying eff ect of work experience on the frequency of certain types of chromosomal aberrations in miners. It is shown that smoking miners with more than 20 years of experience registered an increase in the level of chromosomal aberrations .

Copy-number variation introduced by long transgenes compromises mouse male fertility independently of pachytene checkpoints.

Long transgenes are often used in mammalian genetics, e.g., to rescue mutations in large genes. In the course of experiments addressing the genetic basis of hybrid sterility caused by meiotic defects in mice bearing different alleles of Prdm9, we discovered that introduction of copy-number variation (CNV) via two independent insertions of long transgenes containing incomplete Prdm9 decreased testicular weight and epididymal sperm count. Transgenic animals displayed increased occurrence of seminiferous tubules with apoptotic cells at 18days postpartum (dpp) corresponding to late meiotic prophase I, but not at 21 dpp. We hypothesized that long transgene insertions could cause asynapsis, but the immunocytochemical data revealed that the adult transgenic testes carried a similar percentage of asynaptic pachytene spermatocytes as the controls. These transgenic spermatocytes displayed less crossovers but similar numbers of unrepaired meiotic breaks. Despite slightly increased frequency of metaphase I spermatocytes with univalent chromosome(s) and reduced numbers of metaphase II spermatocytes, cytological studies did not reveal increased apoptosis in tubules containing the metaphase spermatocytes, but found an increased percentage of tubules carrying apoptotic spermatids. Sperm counts of subfertile animals inversely correlated with the transcription levels of the Psmb1 gene encoded within these two transgenes. The effect of the transgenes was dependent on sex and genetic background. Our results imply that the fertility of transgenic hybrid animals is not compromised by the impaired meiotic synapsis of homologous chromosomes, but can be negatively influenced by the increased expression of the introduced genes.

FEATURES OF THE KARYOTYPE OF WHITE-HEADED COWS OF UKRAINIAN BREED

The White-Headed Ukrainian breed of cattle belongs to breeds of a dairy direction of productivity and belongs to small disappearing breeds. According to calculations, in accordance with the FAO recommendations, the White-Headed Ukrainian breed of cattle is at risk. The aim of the work was to establish the karyotype variability of White-Headed Ukrainian cows, whose animals belong to closed gene pool herds. Cytogenetic monitoring showed that the quantitative chromosome abnormalities, in particular aneuploidy, in White-Headed Ukrainian cows of two groups according to the purpose of the cow (selection nucleus and production group) did not exceed the spontaneous level of this variability (1.5-8.3%) and was 6.0% and 7.0% respectively. A multiple increase in the number of chromosomes (polyploidy) was not detected. The average value of metaphase plates with asynchronous differences in the centromeric regions of chromosomes was 1.0% and corresponded to the level of this variability characteristic of the species Bos taurus. The frequency of structural chromosome abnormalities (chromosomal breaks) in animals of the two groups was 2.3% and 2.0%, respectively, which corresponds to the norm characteristic of cattle with spontaneous mutagenesis. The results of the micronucleus test showed that the proportion of lymphocytes with micronuclei in animals of the two groups was in the range of 4.8 - 5.0%, dinuclear lymphocytes 5.6-6.4 %, and the proportion of dividing cells (mitotic index) was 2.8-3.8 %. The frequency of cells with aneuploidy in cows of the Ukrainian Black-Spotted dairy breed of this farm was established higher than the spontaneous level. The difference between the mean values on this basis in cows of White-Headed Ukrainian and Ukrainian Black-Spotted dairy breeds was statistically significant at P&gt; 0.99. In cows of the Ukrainian Black-Spotted dairy breed under conditions of intensive use, an increase in the frequency of metaphases with aneuploidy was observed, which was not manifested in cows of the White-Headed Ukrainian breed.

Nucleolar organizer region banding in crossbred and non-descript pigs of India.

Aim:The objective of this experiment was to study the nucleolar organizer region (NOR)-banding pattern in Large White Yorkshire (LWY) crossbred and non-descript pigs and finding differences in the number of NORs between animals and between genetic groups.Materials and Methods:The experiment was carried out on 15 females, and 15 males of LWY crossbred and non-descript pigs to study NOR-banding pattern by employing ammoniacal silver staining technique.Results:A total of 63 and 65 number of good metaphases were prepared in LWY crossbred, and non-descript pigs and a total of 168 and 143 number of NORs were detected on the 8th and 10th chromosomes in both genetic groups, respectively. The mean number of NORs per metaphase was 2.67 and 2.20 in LWY crossbred and non-descript pigs, respectively. LWY crossbred pig had high mean number of silver-stained NORs (Ag-NORs) per metaphase compared to non-descript pig. In general, it was observed that the highest frequency of metaphases (%) examined had two number of NORs, while the lowest frequency (%) had four number of NORs. The number of NORs observed per metaphase on secondary constrictions of the 8th and 10th chromosome pair in both genetic groups ranged from 2 to 4. The Chi-square test of significance revealed that the observed frequencies do not differ significantly from the expected frequencies.Conclusion:The results confirmed differences across breeds in occurrence and number of NORs on chromosomes in pigs. The mean numbers of NORs present per metaphase vary between the animals indicating the existence of polymorphism for the number of NORs. A higher number of Ag-NORs were observed on chromosome pair 10 in both the genetic groups. It was concluded that NORs were more morphologically distinct and greater on chromosome pair 10 than on pair 8, which suggests a dominant role of chromosome 10 in the global production of ribosomal RNA.

Lethal and nonlethal chromosome aberrations by gamma rays and heavy ions: a cytogenetic perspective on dose fractionation in hadron radiotherapy

Background: With ions heavier than protons now being used in radiotherapy, consideration has been given to the use of fewer dose fractions. Because it is among the best surrogate measures of cell killing and carcinogenic potential, damage to chromosomes relates to the clinical objectives of minimizing normal tissue damage, and lessening the chance of treatment-related second cancers. Curvature in acute dose response relationships plays an important role in radiotherapy, since it implies that a dose-fractionation effect will be observed. Methods: Human lymphocytes, irradiated with either 662 keV 137 Cs gamma rays or 1 GeV/amu 56 Fe ions, were assessed for chromosome aberrations at their first postirradiation mitosis by mFISH. Results: As measured by the frequency of metaphases not containing lethal aberrations, the survival curve for iron ions was exponential, whereas that for gamma rays was decidedly curvilinear. We observed an apparent slight curvature in the dose response for total chromosome exchange breakpoints following exposure to 56 Fe ions, but a curvilinear model did not receive overwhelming statistical support. More importantly, support for the curvilinear model decreased when only cells containing transmissible (nonlethal) aberrations were considered. This is in stark contrast to the results for low LET 137 Cs photons, where curvilinearity in the dose response had overwhelming support irrespective of whether total or only nonlethal aberrations were considered. Conclusions: We make the assumption that high atomic number, high-energy (HZE) iron ions mimic the biological effects of the high-dose/high-LET (Bragg-peak) region of ions used in hadron therapy. To the extent this is true our results suggest that fractionation would not change the biological response for cell killing within the target volume. We further assume that the biological effects of gamma photons are principally equivalent to those of the low-dose/low-LET entrance (plateau) region of the dE/dx profile. In that case, fractionation is expected to elicit considerable sparing for the low-LET/low-dose entrance region occupied by normal tissues. Consequently, while hypo-fractionation would provide no additional benefit insofar as tumor cell killing is concerned, it may well increase the risk of normal tissue damage. Since most secondary solid tumors are thought to be formed near the treatment margin of the high-LET/highdose region, neither will fractionation have an effect on the induction of cells containing only nonlethal aberrations. Consequently, the incidence of second cancers is unlikely to be unaffected by any type of fractionation schedule. Thus, from a purely cytogenetic perspective, we conclude that hypo-fractionated hadron radiotherapy is a precarious proposition to be considered with due caution.

Relationship Between Follicular Fluid and Serum Levels of Vitamin C and Oocyte Morphology and Embryo Quality in Patients Undergoing In Vitro Fertilization

Objectives: This study aimed to determine the relationship between follicular fluid (FF) and serum level of vitamin C and oocytes morphology and embryo quality in patients undergoing in vitro fertilization (IVF). Materials and Methods: This is a cross-sectional study which was conducted on 50 women undergoing IVF in Al-Zahra hospital in Rasht, Iran during 2014. Vitamin C level in FF and serum were measured using high-performance liquid chromatography (HPLC). Retrieval oocyte morphology and obtained embryo quality were evaluated using inverted optical microscope. Results: In our study 434 oocytes and 199 embryos were assessed. Frequencies of metaphase II (MII) oocytes were significantly higher at 1-1.5 mg/dL level of vitamin C in FF (86.4%) and 0.5-1 mg/dL serum level of vitamin C (83.2%). Odds of having MII oocytes at the 1-1.5 mg/dL level of vitamin C in FF (odds ratio [OR] = 15.02, 95% CI = 2.77-81.54) was 15 times greater than the level of 1.5-2.3 mg/dL. The most frequency of embryo with Z1 or Z2 quality were observed at 0.1-0.5 mg/dL level of vitamin C in FF (69.3%) and 0.5-1 mg/dL level of vitamin C in serum (84.3%). odds of having embryo with Z1 or Z2 quality, at the 0.1-0.5 mg/dL level of vitamin C in FF (OR = 3.08, 95% CI = 1.21-7.83), was 3 times greater compared to the 1-2.3 mg/dL level. Conclusion: At the certain level of vitamin C in FF, clinicians may have oocytes with higher maturity and embryos with better quality.

Cytogenetic analysis of the residents of North Ossetia living in ecologically different regions

Background. Cytogenetic biomarkers are the most frequently used end point in human biomonitoring studies and are used extensively to assess the impact of environmental, occupational and medical factors on genomic stability.Materials and methods. The study was conducted on blood samples from 55 residents living in ecologically different areas of North Ossetia: 47 adults with the mean age of 34 ± 3.2 and 8 children with the mean age of 14 ± 1.0. Chromosome aberration analysis was performed on peripheral blood lymphocytes, cultures were incubated for 48h.Results. The results of the study showed a statistically significant difference between the frequencies of cells with chromosome aberrations among the residents living in ecologically different areas of North Ossetia. During the cytogenetic studies, three groups of residents living at different distances from the pollution source (a metallurgical enterprise) were examined, and significant variations of chromosomal aberrations frequencies have been found. In residents living up to 3 km from the enterprise the average frequency of chromosome aberrations was maximal (4.3 ± 0.5), while in residents from remote areas (more than 5 km) the frequency was 2.8 ± 0.3, р ≤ 0.003. Among the examined children frequencies of chromosomal aberrations were 4.1 ± 0.7 and 1.3 ± 0.5, respectively (р ≤ 0.04). Conclusion. A high average frequency of metaphases with aberrations is an indication of adverse environmental conditions which have developed after the accident. Increase of the proportion of chromosome type aberrations in the spectrum of cytogenetic damage among residents of North Ossetia allows to assume the presence of mutagenic effects of chemical as well as radiation nature. "Afobazol" has shown protective properties in donors blood of residents of the region affected by anthropogenic press.

Cytogenetic analysis of residents of North Ossetia contacting with toxic factors

Background. The use of cytogenetic assays in the surveillance of populations occupationally exposed to a variety of xenobiotics originates from the assumption that chromosomal alterations might be causally involved in early stages of carcinogenesis. Materials and methods. This study was designed to assess genotoxic damage in somatic cells of workers contacting with harmful factors after the accident in metallurgical plant. The study was conducted on 29 workers (with the mean age of 44 ± 2.5) performing various jobs with harmful factors. Control group was recruited from occupationally unexposed individuals and comprised 18 persons with the mean age of 30 ± 2.2 and inplant control was 5 employees from metallurgical plant (accountants) with the mean age of 32 ± 5.9. Chromosome aberration analysis was performed on peripheral blood lymphocytes, cultures were incubated for 48h. Results. Among the residents with occupational hazards, a statistically significant increase of the frequency of the cells with chromosome aberrations in comparison with the control group (5.2 ± 0.3 and 2.4 ± 0.3, respectively). The highest frequency of cells with structural abnormalities was observed among steel plant workers (6.3 ± 0.6). Conclusion. Our findings suggest that in peripheral blood lymphocytes of residents contacting with harmful factors may induce clastogenic effects, indicating a potential health risk in populations of workers. A high average frequency of metaphases with aberrations and characterization of quality spectrum of cytogenetically violations is an indication of adverse environmental conditions which have developed after the accident.

Metaphase arrest and delay in cell cycle kinetics of root apical meristems and mouse bone marrow cells treated with leaf aqueous extract of Clerodendrum viscosum Vent

To study cell cycle delay and metaphase arresting activity of leaf aqueous extract of Clerodendrum viscosum Vent. (LAECV) in root apical meristems and mouse bone marrow cells. Cell cycle delay and metaphase arresting activities of LAECV were analysed, in root apical meristems of onion and wheat, and in mouse bone marrow cells, by scoring mitotic index, metaphase frequency and transition of cells from metaphase to anaphase. Colchicine was used as the standard metaphase arresting drug. Phytochemicals present in LAECV were detected and their phytotoxic activity was evaluated by analysing green-gram (Vigna radiata) seedling's root growth retardation and branch root swelling phenomenon. LAECV treatment resulted in dose-dependent root growth retardation of green-gram seedling root length (P < 0.01) and half maximal growth inhibitory concentration (IC(50) ) of LAECV was 0.87 mg/ml at 144 h. In onion and wheat root meristem cells the mitotic index decreased, metaphase frequency increased and transition from metaphase to anaphase reduced. Experimentation with mouse bone marrow cells indicated that LAECV induced metaphase arrest (164.3% increase in arrested metaphases per 300 mg/kg body weight, over 2.5 h). Phytochemicals like carbohydrates, glycosides, saponins, terpenoids, triterpenoids, tannins and trace amounts of alkaloids were detected in LAECV. It may be said that LAECV contains mitostatic and metaphase arresting components that are able to induce significant metaphase arrest in root apical meristems and also in mouse bone marrow cells.

Analysis of Chromosome Aberrations Contained in Vitro Human Peripheral Blood Lymphocytes After Treatment with Ceftriaxone

The invention and use of antibiotics in treating infections is one of the greatest achievements of the twentieth century medicine. Antibiotics are one of the categories of pharmaceuticals with a broad and increasing application. The goal of this paper is to analyze the influence of different set of test concentrations of ceftriaxone antibiotics on the occurrence of chromosome aberrations after in vitro treatment with concentrations: 0.15 mg/ml, 0.25 mg/ml and 0.50 mg/ml. In the study was used the blood of healthy donors in vitro, treated with different concentrations of ceftriaxone. Ceftriaxone is a semisynthetic cephalosporine third generation antibiotic, with broad spectrum of activity and with specific characteristics (Nerlove et al. 1996). As a biomarker of genetic damage are used the methods of cultivation of peripheral blood lymphocytes and analysis of chromosome aberrations. Cytogenetic analysis of ceftriaxone genotoxicity was performed in 48-hour culture of human peripheral blood lymphocytes by test of standard chromosome aberration analysis according to Moorhead, with certain modifications. Insight into the frequency and type of chromosome aberrations is obtained by analyzing 100 metaphases per sample. By the analysis of 100 metaphases per sample was determined that the relative frequency of metaphases with chromosome aberrations is increased with increasing concentrations of ceftriaxone in lymphocyte culture. The increase in the frequency of structural aberrations was also positively correlated with the applied ceftriaxone concentrations. Metaphases with numerical and structural aberrations are registered in lymphocyte cultures treated with ceftriaxone concentration of 0.25 mg/ml and 0.50 mg/ml, but this increase was not significant compared to the control cells cultures. Significantly increased frequency of metaphases with structural chromosome aberrations in cultured human peripheral blood lymphocytes treated with concentrations of 0.25 mg/ml and 0.5 mg/ml compared to the control confirming clastogenic potential of this drug. Ceftriaxone also expressed aneugenic activity at the highest test concentration (0.50 mg/ml), confirming a statistically significant difference in the frequency of numerical aberrations in cultures treated with doses of 0.5 mg/ml.

The role of MOF in the ionizing radiation response is conserved in Drosophila melanogaster.

In Drosophila, males absent on the first (MOF) acetylates histone H4 at lysine 16 (H4K16ac). This acetylation mark is highly enriched on the male X chromosome and is required for dosage compensation in Drosophila but not utilized for such in mammals. Recently, we and others reported that mammalian MOF, through H4K16ac, has a critical role at multiple stages in the DNA damage response (DDR) and double-strand break repair pathways. The goal of this study was to test whether mof is similarly required for the response to ionizing radiation (IR) in Drosophila. We report that Drosophila mof mutations in males and females, as well as mof knockdown in SL-2 cells, reduce post-irradiation survival. MOF depletion in SL-2 cells also results in an elevated frequency of metaphases with chromosomal aberrations, suggesting that MOF is involved in DDR. Mutation in Drosophila mof also results in a defective mitotic checkpoint, enhanced apoptosis, and a defective p53 response post-irradiation. In addition, IR exposure enhanced H4K16ac levels in Drosophila as it also does in mammals. These results are the first to demonstrate a requirement for MOF in the whole animal IR response and suggest that the role of MOF in the response to IR is conserved between Drosophila and mammals.

Role of quercetin on mitomycin C induced genotoxicity: Analysis of micronucleus and chromosome aberrations in vivo

Quercetin, a flavonol group of plant flavonoid, has generated immense interest because of its potential antioxidant, anti-proliferative, chemoprotective, anti-inflammatory and gene expression modulating properties. However, the pro-oxidant chemistry of quercetin is important as it is related to the generation of mutagenic quinone-type metabolites. In the present study, 25 mg/kg, 50 mg/kg and 100 mg/kg of quercetin given through the intra peritoneal (i.p.) route induced 2.31 ± 0.27%, 4.72 ± 0.58% and 6.38 ± 0.68% (control value = 0.67 ± 0.30%) respectively, of cells with micronucleus (MN) in polychromatic erythrocytes in bone marrow cells and 10.93 ± 0.98%, 10.00 ± 0.89% and 14.27 ± 3.94% (control 2.61 ± 0.48) of cells with chromosome aberrations (CA) following 24 h of the treatments. Higher frequencies of MN and CA were also observed after 48 h of the treatments. To verify the effect of route of treatment on the quercetin induced damage, 100 mg/kg b.w. was given through oral route which declined frequency of MN ( P < 0.001) as well as CA ( P < 0.05) as compared to the i.p. route for the same dose. Quercetin also induced higher frequency of metaphases with sticky chromosomes and C-mitosis. Pre-treatment with quercetin significantly reduced the frequency of mitomycin C (MMC) induced MN as well as CA, but no clear correlation between the dose and effect could be observed. Further studies are required to elucidate the possible interaction of quercetin with DNA as well as with other DNA damaging agents like MMC in vivo. The protective action of quercetin was not enhanced when given orally. Our findings suggest that quercetin may result in genomic instability in the tested dose range and significant reduction in MMC induced genotoxicity in the highest dose tested. These effects of quercetin are to be taken into consideration while evaluating the possible use of quercetin as a therapeutic agent.

Quantitative characteristics of chromosomal aberration frequency in the residents of the regions with different levels of cancer incidences

We present the results of cytogenetic monitoring of the districts in Kemerovo region, which differ in standardized indices of cancer incidence. It has been shown that residents of the districts with high incidence of malignancies had higher average frequency of metaphases with chromosomal aberrations than the control group (4.06 +/- 0.12% and 2.76 +/- 0.13%, respectively). This difference is caused primarily by single or paired fragments. The increase in the frequency of aberrant metaphase incidence in the districts with elevated cancer frequency was observed both in the male and female groups as well as both in adults and children.

Chromosomal instability in the lymphocytes of breast cancer patients.

Genomic instability in the tumor tissue has been correlated with tumor progression. In the present study, chromosomal aberrations (CAs) in peripheral blood lymphocytes (PBLs) of breast tumor patients were studied to assess whether chromosomal instability (CIN) in PBLs correlates with aggressiveness of breast tumor (i.e., disease stage) and has any prognostic utility. Cultured blood lymphocyte metaphases were scored for aberrations in 31 breast cancer patients and 20 healthy age and sex-matched controls. A variety of CAs, including aneuploidy, polyploidy, terminal deletions, acentric fragments, double minutes, chromatid separations, ring chromosome, marker chromosome, chromatid gaps, and breaks were seen in PBLs of the patients. The CAs in patients were higher than in controls. A comparison of the frequency of metaphases with aberrations by grouping the patients according to the stage of advancement of disease did not reveal any consistent pattern of variation in lymphocytic CIN. Neither was any specific chromosomal abnormality found to be associated with the stage of cancer. This might be indicative of the fact that cancer patients have constitutional CIN, which predisposes them to the disease, and this inherent difference in the level of genomic instability might play a role in disease progression and response to treatment.

Cytogenetic analysis of genotoxic effects in subjects employed in heat power industry

Chromosomal aberration rate has been estimated in peripheral blood lymphocytes of subjects occupationally exposed to a set of hazardous factors (employees of the Kemerovo Heat Power Plant). The frequency of metaphases with aberrations in the workers (3.23 +/- 0.26%, N = 104) is significantly higher than in control subjects (2.11 +/- 0.28%, N = 70). The cytogenetic aberrations did not depend on the sex, age, duration of employment, or smoking.