Cytokinesis-block Micronucleus Cytome Assay Research Articles

Genomic Instability and Cytotoxicity Evaluation of Two Communities Exposed to Pesticides in the Mexicali Valley by the L-CBMN Assay.

The continuous biomonitoring of a population directly or indirectly exposed to pesticides could be an additional tool for decision makers to improve their health conditions. In this work, we performed biomonitoring on two groups of people from the Mexicali Valley who were continuously exposed to pesticides using the cytokinesis-block micronucleus cytome assay (L-CBMN) to evaluate cytotoxic and genotoxic damage in human peripheral blood lymphocytes. The study groups comprised 14 indigenous Cucapah with non-vegetarian habits (NV group) from Ejido el Mayor (32.12594°, -115.27265°) and 21 lacto-ovo vegetarian (LOV) persons from the Seventh-day Adventist Church of Ejido Vicente Guerrero (32.3961°, -115.14023°). The L-CBMN assay determines the nuclear division index (NDI), apoptosis, necrosis, micronuclei (MNs), nuclear buds (NBUDs), and nucleoplasmic bridges (NPBs). Our results show that, regardless of diet or daily habits, both the studied groups presented with cytogenotoxic damage compared with non-exposed pesticide individuals, without modifications to the nuclear division index. In the rest of the evaluated biomarkers, the NV group exhibited greater cytotoxic and genotoxic damage than the LOV group. Nevertheless, individuals practicing a lacto-ovo vegetarian diet (LOV) showed lower damage than those with non-vegetarian habits (NV), suggesting a better antioxidant response that helps decrease the genotoxic damage due to the enhanced intake of folates and antioxidants from a plant-based diet.

Effect of Low Dietary Folate on Mouse Spermatogenesis and Spindle Assembly Checkpoint Dysfunction May Contribute to Folate Deficiency-Induced Chromosomal Instability in Cultured Mouse Spermatogonia.

Folate, as the initial substrate in one-carbon metabolism, is involved in the synthesis of important substances such as DNA, RNA, and protein. Folate deficiency (FD) is associated with male subfertility and impaired spermatogenesis, yet the underlying mechanisms are poorly understood. In the present study, we established an animal model of FD to investigate the effect of FD on spermatogenesis. GC-1 spermatogonia were used as a model to investigate the effect of FD on proliferation, viability, and chromosomal instability (CIN). Furthermore, we explored the expression of core genes and proteins of spindle assembly checkpoint (SAC), a signaling cascade ensuring accurate chromosome segregation and preventing CIN during mitosis. Cells were maintained in medium containing 0, 20, 200, or 2000 nM folate for 14 days. CIN was measured by using a cytokinesis-blocked micronucleus cytome assay. We found that sperm counts decreased significantly (p < 0.001) and the rate of sperm with defects in the head increased significantly (p < 0.05) in FD diet mice. We also found, relative to the folate-sufficient conditions (2000 nM), cells cultured with 0, 20, or 200 nM folate exhibited delayed growth and increased apoptosis in an inverse dose-dependent manner. FD (0, 20, or 200 nM) significantly induced CIN (p < 0.001, p < 0.001, and p < 0.05, respectively). Moreover, FD significantly and inverse dose dependently increased the mRNA and protein expression of several key SAC-related genes. The results indicate that FD impairs SAC activity, which contributes to mitotic aberrations and CIN. These findings establish a novel association between FD and SAC dysfunction. Thus, FD-impaired spermatogenesis may be partly due to genomic instability and proliferation inhibition of spermatogonia.

The Relationship between Telomere Length and Nucleoplasmic Bridges and Severity of Disease in Prostate Cancer Patients

Telomeres are repetitive nucleotide (TTAGGG) sequences that stabilize the chromosome ends and play an important role in the prevention of cancer initiation and progression. Nucleoplasmic bridges (NPBs) are formed when chromatids remain joined together during mitotic anaphase either due to mis-repair of DNA breaks or due to chromatid end fusion as a result of telomere loss or telomere dysfunction. We tested the hypotheses that (i) telomere length (TL) is shorter in prostate cancer (PC) patients relative to healthy age-matched individuals, (ii) TL differs in different stages of PC and (iii) shorter TL is significantly correlated with NPBs formation in PC cases. TL was measured in whole blood by well-established quantitative PCR method and the frequency of NPBs was measured in lymphocytes using cytokinesis-block micronucleus cytome (CBMNcyt) assay. Our results indicate that TL is shorter and NPBs are increased in PC patients relative to age-matched healthy controls. Furthermore, TL was significantly shorter (p = 0.03) in patients with a Gleason score more than 7 and there was also a significant trend of decreasing TL across all three stages (p trend = 0.01; Gleason score &lt;7, 7 and &gt;7). Furthermore, TL was significantly inversely correlated with NPB frequency in PC patients (r = −0.316; p = 0.001) but not in controls (r = 0.163; p = 0.06) and their relationships became stronger with higher Gleason scores. More studies are required that can confirm our observations and explore mechanistic differences in the role of telomeres in NPB formation in PC cases relative to non-cancer cases.

Reduction of oral pathogens and oxidative damage in the CAL 27 cell line by Rosmarinus officinalis L. and Taraxacum officinale Web. extracts

Ethnopharmacological relevanceDandelion (Taraxacum officinale Web.) and rosemary (Rosmarinus officinalis L.) are treasured botanicals with a long usage history in traditional herbal practices worldwide. Dandelion was used to treat kidney, spleen, and liver disease, as well as cardiovascular disease, diabetes, and bacterial infections, whereas rosemary was used to treat pain, spasms, and to improve blood circulation. Aim of the studyThe aim of this study was to determine the influence of rosemary and dandelion leaves aqueous extracts on the human tongue epithelial carcinoma cell line (CAL 27) at the level of interaction between oral microbiota and tongue epithelial cells, genomic damage, and H2O2 - induced oxidative damage protection. Materials and methodsThe polyphenolic composition of the extracts was determined by spectrophotometric and HPLC analyses. After extract treatment, cytotoxic impact and ROS generation in CAL 27 cells were measured using the MTT assay and the 2',7'-dichlorofluorescein-diacetate (DCFH-DA) assay, respectively. Microdilutions were applied to investigate the antimicrobial and adhesive properties against representatives of the oral microbiota. The single-cell gel electrophoresis (comet assay) and cytokinesis-blocked micronucleus cytome assay (CBMN cyt) were used to detect induced genomic damages. ResultsBoth extracts increased the adhesion of the lactic acid bacteria L. plantarum but decreased the adhesion of the bacterial pathogens S. enterica serovar Typhimurium LT21 and E. coli K-12 MG1655 adhesion onto CAL 27 cells. 1 h treatment with 5x concentrated dandelion extract and 1x, 2.5x, and 5x of rosemary extract caused an increase in comet tail intensity. CBMN cyt results demonstrated a significant increase in micronucleus formation even at concentrations several times lower than the usual bioactive compound concentrations found in a cup of beverage, with higher concentrations also inducing cell apoptosis and necrosis. Rosemary extract showed a protective effect against H2O2 - induced oxidative damage by decreasing the apoptotic cell number, probably preventing mutations leading to tumor aggressiveness, invasion, and metastasis. ConclusionsBoth tested extracts demonstrated their usefulness in maintaining good oral bacteria balance and their protective capability as powerful antitumor agents by causing a protective apoptotic effect in tumor cell line already at the dosage of an average daily cup.

Assessment of genotoxic instability markers in peripheral blood lymphocytes of breast cancer patients: a case control study

Changes in genetic constitution of an individual leads to uncontrollable cell growth and tumour formation. The acquisition of genomic instability predisposes cells to accumulate stable genome mutations causing carcinogenesis. The cytokinesis-block micronucleus cytome assay (CBMN), a well-established marker assay for chromosomal mutagen sensitivity, was applied in this study enrolling breast cancer patients and age and sex-matched controls. This work aimed to assess the predictive value of the frequency of genotoxic markers in peripheral blood lymphocytes for the risk/susceptibility of breast cancer. Samples from a hundred untreated breast cancer patients and age and sex matched controls were enrolled in the study from Government Medical College, Alappuzha. The genomic instability was assessed using cytokinesis block micronucleus assay where cytome events were marked. The results showed a significant increase in the frequency of micronucleus, nucleoplasmic bridge, and buds in the binucleated cells of breast cancer patients compared to the control samples. The variability was assessed by CBMN Cyt assay. The frequency of Micronuclei and Nucleoplasmic buds was significantly higher in the patient groups than in the controls (p < 0.0001). In Breast cancer patients, the median (IQR) range of MNi was 12(6), the Nucleoplasmic bridge 3(3) and the Nuclear buds were 2(1) and, in the controls, it was 6(5), 1(2) and 1(1) respectively. A larger difference in the frequency of genetic markers in cancer patients over control cases support a significant role of these markers in the population screening of individuals at high risk of cancer. Communicated by Ramaswamy H. Sarma

Toxicogenic effects of the mushroom Ganoderma lucidum on human liver and kidney tumor cells and peripheral blood lymphocytes.

Ganoderma lucidum (Curtis) P. Karst., a bioactive mushroom with medicinal properties, is known to exert immunomodulatory, anti-inflammatory, hypocholesterolemic, hypoglycemic, and hepatoprotective effects. In this study, the effects of the G. lucidum fruiting body dry extract (GLE) on human liver (HepG2/C3A) and kidney (786-O) tumor cells and peripheral blood lymphocytes were evaluated. MTT-based cytotoxicity, trypan blue-based cell viability, comet, and cytokinesis-block micronucleus cytome assays were performed, and the production of reactive oxygen species was evaluated in vitro. GLE was toxic to the tumor cells, decreasing their viability by increasing their production of reactive oxygen species and inducing damage to their DNA. By contrast, only high concentrations of GLE were toxic to lymphocytes and decreased their viability, whereas low concentrations increased lymphocyte viability. Moreover, primary DNA damage was induced by GLE only at the highest concentration tested. G. lucidum shows potential antitumor effects against cancerous kidney and liver cells, exhibiting cytotoxic and genotoxic activity at low concentrations, whereas the same effects in lymphocytes are mediated only at high concentrations. This mushroom has the potential to be biotechnologically developed into a therapeutic agent for diseases, such as cancer.

Genotoxic and cytotoxic effects of thiomersal and paracetamol combination

Background: Thiomersal is used as a preservative of some vaccines or as a trace from the pathogen inactivation process in vaccine production. Prophylactic use of paracetamol upon vaccination is still common, even though paracetamol decreases immune response on some vaccines. Considering the cytotoxic and genotoxic potential of thiomersal and paracetamol and possible interaction in vivo, in vitro study was performed. Methods: The genotoxic and cytotoxic effects of thiomersal and paracetamol combination were examined on human lymphocyte cultures by using two methods: analysis of chromosomal aberrations and cytokinesis-block micronucleus cytome assay. Blood samples of three healthy donors were analyzed with the following concentrations of tested substances: thiomersal 1 µg/ml and 0.5 µg/ml, paracetamol 20 µg/ml, thiomersal 0.5 µg/ml with paracetamol 20 µg/ml and thiomersal 1.0 µg/ml with paracetamol 20 µg/ml. Results: The analysis of structural chromosomal aberrations was significantly increased in all treated cultures. In cells treated with the combination of thiomersal 1 µg/ml and 20 µg/ml of paracetamol, the number of aberrations was significantly decreased. Cytokinesis-block micronucleus cytome assay analyses showed significantly increased micronucleus frequency in lymphocytes cultivated with thiomersal 1 µg/ml compared to lymphocytes cultures exposed to thiomersal 0.5 µg/ml. Conclusions: Induction of structural chromosome aberrations and micronucleus is shown as a sign of genotoxicity for the examined concentrations of thiomersal and paracetamol. The suppressing effect of paracetamol on thiomersal genotoxicity in lymphocytes culture treated with thiomersal was shown to be indicative of further examination of paracetamol use in the prevention of genotoxicity.

Analysis of the cytotoxic and genotoxic effects in a population chronically exposed to coal mining residues

During coal mining activities, many compounds are released into the environment that can negatively impact human health. Particulate matter, polycyclic aromatic hydrocarbons (PAHs), metals, and oxides are part of the complex mixture that can affect nearby populations. Therefore, we designed this study to evaluate the potential cytotoxic and genotoxic effects in individuals chronically exposed to coal residues from peripheral blood lymphocytes and buccal cells. We recruited 150 individuals who lived more than 20 years in La Loma-Colombia and 120 control individuals from the city of Barranquilla without a history of exposure to coal mining. In the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay, significant differences in the frequency of micronucleus (MN), nucleoplasmic bridge (NPB), nuclear bud (NBUD), and apoptotic cells (APOP) were observed between the two groups. In the buccal micronucleus cytome (BM-Cyt) assay, a significant formation of NBUD, karyorrhexis (KRX), karyolysis (KRL), condensed chromatin (CC), and binucleated (BN) cells was observed in the exposed group. Considering the characteristics of the study group, a significant correlation for CBMN-Cyt was found between NBUD and vitamin consumption, between MN or APOP and meat consumption, and between MN and age. Moreover, a significant correlation for BM-Cyt was found between KRL and vitamin consumption or age, and BN versus alcohol consumption. Using Raman spectroscopy, a significant increase in the concentration of DNA/RNA bases, creatinine, polysaccharides, and fatty acids was detected in the urine of individuals exposed to coal mining compared to the control group. These results contribute to the discussion on the effects of coal mining on nearby populations and the development of diseases due to chronic exposure to these residues.

The influence of vitamin D supplementation and strength training on health biomarkers and chromosomal damage in community-dwelling older adults

Older adults lack of proper physical activity which is often accompanied by vitamin D deficiency. Those factors are known to contribute to health issues in the later years of life. The main goal of this intervention study was to investigate the effect of different vitamin D supplementation strategies for 4 weeks solely or combined with a 10-week strength training program on chromosomal stability in peripheral blood mononuclear cells in community-dwelling older people. One hundred women and men (65–85 years) received either vitamin D3 daily (800 IU), a monthly dose (50.000 IU) or placebo for 17 weeks. All groups received 400 mg calcium daily. The fitness status of the study participants was measured using the 30- second chair stand test, the handgrip strength test and the 6-min walk test. The cytokinesis block micronucleus cytome (CBMN) assay was applied to analyze chromosomal anomalies, including cytotoxic and genotoxic parameters. Changes in antioxidant markers were measured in plasma.Walking distance and chair stand performance improved significantly. Increased levels of the parameters of the CBMN assay were detected for all intervention groups at study end. At baseline micronuclei (MNi) frequency correlated significantly with BMI in both sexes (females: r = 0.369, p = 0.034; males: r = 0.265, p = 0.035), but not with vitamin D serum levels. In females, body fat (r = 0.372, p < 0.001) and functional parameter using the 30-s chair stand test (r = 0.311, p = 0.002) correlated significantly with MNi frequency. Interestingly, not vitamin D supplementation but 10 weeks of resistance training increased MNi frequency indicating elevated chromosomal instability and also adverse effects on antioxidant markers including glutathione and FRAP were detected in the group of community-dwelling older adults.

Effects of Curcumin and Soy Isoflavones on Genomic Instability of Human Colon Cells NCM460 and SW620.

Curcumin (CUR) and soy isoflavones (SIs) are two plant-based polyphenols that have attracted much attention, because of their extensive anticancer and health maintenance effects. However, the relevant molecular mechanisms are still uncertain. Genomic instability (GIN) refers to a combination of gene abnormal amplification, sequence deletion, ectopic, and other types of gene damage in cells, and it is one of the main factors causing cells to lose normal physiological functions. Therefore, we used the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay as the main research method to analyze the effects of CUR and SIs on the GIN of human normal colon cells NCM460 and colon cancer cells SW620. Results show that CUR (12.5 μM) could reduce the apoptosis of NCM460 and maintain its genomic stability while inhibiting the proliferation of SW620 and promoting its apoptosis. There was no difference in the promoting effect of GIN between SW620 and NCM460 using SIs (3.125-50 μM). When the two polyphenols (v/v = 1/1, 1.5625-6.25 μM) were mixed, they could promote the proliferation and GIN of the NCM460 and SW620 cells, but we did not find that combining the two produced a better effect on the cells. In conclusion, CUR has more prominent health and anticancer effects, and it may become a dietary recommendation for daily health maintenance and a potential adjuvant drug for cancer treatment.

Protective Effects of Arbutus unedo L. Honey in the Alleviation of Irinotecan-Induced Cytogenetic Damage in Human Lymphocytes-An In Vitro Study.

Strawberry tree (Arbutus unedo L.) honey (STH) has been used since ancient times as a folk medicine remedy, especially in certain Mediterranean countries. This honey, rich in phenolic content, is well recognized for its antioxidant, anti-inflammatory, and antimicrobial activities, and is used for the treatment of skin lesions as well as gastrointestinal and respiratory disorders. This study investigated whether STH alleviates genome damage in human peripheral blood lymphocytes produced by the cytotoxic drug irinotecan. The phenolic profile of STH was previously estimated by ultra-high-performance liquid chromatography coupled to a linear ion trap-Orbitrap hybrid mass spectrometer. The effects of STH were evaluated at three concentrations (1×, 5×, and 10×), based on the daily consumption of the honey by an adult person. After 2 h of in vitro exposure, standard lymphocyte cultures for the analysis of chromosome aberrations and the cytokinesis-block micronucleus cytome assay were established. Our results demonstrate that STH offered remarkable geno- and cytoprotection when administered with irinotecan. These findings are relevant for drawing preliminary conclusions regarding the in vitro safety of the tested honey. However, further studies are needed with the application of more complex experimental models.

Association of MTHFR C677T polymorphism with risk of preterm birth in Indian mothers: a case–control study

BackgroundSince MTHFR is the key enzyme in folate metabolism, its reduction can lead to hyperhomocysteinemia, which can have a negative impact on pregnancy outcome. Moreover, MTHFR polymorphism has also been linked with oxidative stress and genotoxicity. Identifying its ethnicity-specific association can help to reduce the incidence of preterm birth (PTB). Material and methods: Age-matched preterm birth mothers (< 37 weeks) and full-term mothers (> 37 weeks) were carefully selected for the study. The polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method was adopted to analyse MTHFR C677T polymorphism. Oxidative stress (OS) analysis was performed by measuring the levels of antioxidants (superoxide dismutase (SOD) and catalase (CAT)) and OS damage markers (lipid peroxidation (LPO), total protein). Genotoxicity was confirmed by the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay. The statistical analysis was performed by Student’s t test, chi-square test, and one-way ANOVA. The relevant risk of premature delivery was represented by odds ratios (ORs) with 95% confidence intervals (95% CIs).ResultsThe MTHFR polymorphism showed statistical significance for PTB outcome with CT and TT genotype frequencies at p < 0.01 and p < 0.05, respectively, between cases and controls. Within the PTB categories (extreme-, very-, moderate-PTB), TT genotype showed statistical significance at (p < 0.05), while CT genotype remained insignificant. Also, statistically high oxidative stress and DNA damage were observed in cases compared to controls for all genotypes. Furthermore, the T allele of the MTHFR gene was found to be linked with significantly increased OS and DNA damage on comparison within the groups.ConclusionsThis study confirms the MTHFR C677T polymorphism, oxidative stress, and genotoxicity biomarkers are associated with the PTB outcome. Analysis of these biomarkers during pregnancy can be of clinical significance.

Characterization of the genotoxic profile of antineoplastic drugs using the cytokinesis-block micronucleus cytome assay

Since antineoplastic agents are frequently used in cancer therapy and able to affect the patient’s DNA, it is important to know the genotoxic consequences on non-cancerous tissue. Therefore, we aimed to characterize the genotoxic profile of antineoplastic drugs belonging to different classes, using the cytokinesis-block micronucleus cytome assay in a human monocytic cell line (THP-1). All tested antineoplastic agents resulted in increased micronucleus formation. Exposure to anthracyclines led to an increased number of vacuolated cells and cell death, while for mitotic spindle inhibitors, (different stages of) cell death and an increased nuclear bud formation was observed. Alkylating agents induce a high proportion of vacuolated cells and increased nuclear bud formation. No striking differences of nuclear division index or nucleoplasmic bridge formation were observed between exposed and non-exposed cells. The here presented class-specific aberrations may facilitate interpretation of genotoxic aberrations when evaluating clinical samples from patients treated with these antineoplastic agents.

Oxidative and chromosomal DNA damage in patients with type I Gaucher disease and carriers

Background and aimsGaucher disease (GD) is caused by a genetic deficiency of the beta-glucocerebrosidase enzyme which results in the accumulation of glucosylceramide in macrophages. This accumulation may induce oxidative stress, resulting in DNA damage in patients with GD. The aim of this study was to assess plasma 8-hydroxy-2′-deoxyguanosine (8-OHdG) levels and cytokinesis-block micronucleus cytome (CBMN-cyt) assay parameters in the peripheral blood lymphocytes of patients with GD and carriers, evaluate the possible associations of these values with GD, and determine whether they can be used as potential biomarkers in GD. MethodsThis study included 20 patients with type 1 GD, six carriers, and 27 age- and sex-matched healthy controls. CBMN-cyt assay parameters in peripheral blood lymphocytes of the patients with GD, carriers, and controls were evaluated and 8-OHdG levels in their plasma samples were measured. ResultsCBMN-cyt assay parameters in patients with GD and carriers were not significantly different when compared with controls (p > 0.05). However, plasma 8-OHdG levels were found to be higher in both patients with GD and carriers than in control subjects (p < 0.01). ConclusionsOxidative DNA damage may be a useful prognostic tool, whereas the CBMN-cyt assay cannot be used as a predictive biomarker of GD.

PARADOXICAL DUAL ROLES OF SOME CYTOKINES INTERPRETED BY CYTOGENETICS INVESTIGATIONS IN IRRADIATED HUMAN BLOOD CULTURES.

Four different cytokines (IL1-β, IL-6, IL-10 and TNF-α) and the cytokinesis-block micronucleus (CBMN) cytome assay investigations were evaluated in six human blood samples. They were divided into the control (nonirradiated) and five gamma-irradiated groups which were exposed to five different doses (0.5, 1, 2, 4 and 8 Gy). Blood groups were cultured in triplets for 72h following 1h of irradiation. Immunological and cytogenetics were investigated parallelly at different irradiation doses to understand the connection between them. Our aim is anchoring the active proliferation action of cytokines by presence of binucleated cells and resting immune system by mononuclear cell. Also, cell death by increasing necrotic cell count and TNF-α concentration. When compared with the control group, 0.5, 1, 2 and 4Gy irradiation groups recorded a gradual increase in the cytokines levels, an increase in the total micronucleated cells (binucleated and mononucleated cells), an increase in necrotic and apoptotic cells counts. While 8Gy irradiation leads to depletion in TNF-α concentration, although the number of necrotic cells was high.

Cytotoxicity and Genotoxicity of Sunset Yellow and Potassium Sorbate in Jurkat Cell Line

Aims: Industrial processed food, pharmaceutical and cosmetical products contain numerous substances the safety of which has been widely concerned. Potassium sorbate (PS) is a common preservative used in a wide-range of products. Sunset yellow (SY) is one of the most commonly used dye in food and pharmaceutical industry. Several studies suggested cytotoxic and genotoxic potential of SY and PS in different cell lines. These effects can lead to organ damage and cancer development. The aim of this study is to investigate cytotoxic and genotoxic potential of two widely used food additives, SY and PS, in Jurkat cell line.&#x0D; Methodology: PrestoBlue assay was used to assess the cytotoxic potential of SY and PS. For observation of DNA damage, cytostatic and cytotoxic effects, the cytokinesis-block micronucleus cytome (CBMN) assay was performed.&#x0D; Results: Decrease of cell viability in Jurkat cell line was observed after 24-hour exposure to both SY and PS. CBMN assay has revealed significant increase of necrotic cells (P&lt;0.05). Genotoxic biomarkers were in physiological range after 24-hour exposure to both analyzed additives.&#x0D; Conclusion: Our findings suggest that SY, as well as PS have cytotoxic potential in Jurkat cell line, as a result of increased number of necrotic cells. Higher cytotoxic effect was caused by SY compared to PS. However, genotoxic potential was not recorded for any of the food additives analyzed.

In vitro analysis of thimerosal genotoxicity and cytotoxicity effect

Background: Thimerosal is an organomercury compound with high mercury content. Thimerosal is located in the market as an effective bacteriostatic in a series of pharmaceutical products, ophthalmic and nasal products, immunoglobulin preparations, and as a preservative in vaccines. Aims and Objectives: Since it is a compound with living content, this study aimed to examine the genotoxic and cytotoxic potential of thimerosal in human lymphocytes culture. Materials and Methods: We used chromosome aberration analysis and cytokinesis-block micronucleus cytome (CBMN-Cyt) assay to test its genotoxic and cytotoxic potential in human lymphocyte culture. Results: Results showed that the frequency of structural chromosome aberrations and CBMN-cyt assay was significantly increased in treated cultures (1 μg/ml and 0.5 μg/ml) compared to the negative control. Conclusion: Obtained results and statistical analysis show that thimerosal is genotoxic and cytotoxic in human lymphocytes in tested concentrations.

Pyrene-polyethylene glycol-modified multi-walled carbon nanotubes: Genotoxicity in V79-4 fibroblast cells

The genotoxicity of pyrene-polyethylene glycol-modified multi-walled carbon nanotubes (MWCNT-PyPEG), engineered as a nanoplatform for bioapplication, was evaluated. Toxicity was assessed in hamster lung fibroblast cells (V79–4). MTT and Cell Titer Blue methods were used to evaluate cell viability. Genotoxicity was measured by the comet assay and the cytokinesis-block micronucleus cytome (CBMN-Cyt) assay, and fluorescence in situ hybridization (FISH) was used to test induction of structural chromosome aberrations (clastogenic activity) and/or numerical chromosome changes (aneuploidogenic activity). Exogenous metabolic activation enzymes were used in the CBMN-Cyt and FISH tests. Only with metabolic activation, the hybrids caused chromosomal damage, by both clastogenic and aneugenic processes.

The suitability of micronuclei as markers of relative biological effect.

Micronucleus (MN) formation is routinely used as a biodosimeter for radiation exposures and has historically been used as a measure of DNA damage in cells. Strongly correlating with dose, MN are also suggested to indicate radiation quality, differentiating between particle and photon irradiation. The “gold standard” for measuring MN formation is Fenech’s cytokinesis-block micronucleus (CBMN) cytome assay, which uses the cytokinesis blocking agent cytochalasin-B. Here, we present a comprehensive analysis of the literature investigating MN induction trends in vitro, collating 193 publications, with 2476 data points. Data were collected from original studies that used the CBMN assay to quantify MN in response to ionizing radiation in vitro. Overall, the meta-analysis showed that individual studies mostly have a linear increase of MN with dose [85% of MN per cell (MNPC) datasets and 89% of percentage containing MN (PCMN) datasets had an R2 greater than 0.90]. However, there is high variation between studies, resulting in a low R2 when data are combined (0.47 for MNPC datasets and 0.60 for PCMN datasets). Particle type, species, cell type, and cytochalasin-B concentration were suggested to influence MN frequency. However, variation in the data meant that the effects could not be strongly correlated with the experimental parameters investigated. There is less variation between studies when comparing the PCMN rather than the number of MNPC. Deviation from CBMN protocol specified timings did not have a large effect on MN induction. However, further analysis showed less variation between studies following Fenech’s protocol closely, which provided more reliable results. By limiting the cell type and species as well as only selecting studies following the Fenech protocol, R2 was increased to 0.64 for both measures. We therefore determine that due to variation between studies, MN are currently a poor predictor of radiation-induced DNA damage and make recommendations for futures studies assessing MN to improve consistency between datasets.

Evidence of chromosomal damage in scleroderma

Evidence of chromosomal damage in scleroderma