Analysis Of Chromosomal Aberrations Research Articles

Quantification of Chromosomal Aberrations in Mammalian Cells.

Maintenance of genome integrity requires efficient and faithful resolution of DNA breaks and DNA replication obstacles. Dysfunctions in any of the processes orchestrating such resolution can lead to chromosomal instability, which appears as numerical and structural chromosome aberrations. Conventional cytogenetics remains as the golden standard method to detect naturally occurring chromosomal aberrations or those resulting from the treatment with genotoxic drugs. However, the success of cytogenetic studies depends on having high-quality chromosome spreads, which has been proven to be particularly challenging. Moreover, a lack of scoring guidelines and standardized methods for treating cells with genotoxic agents contribute to significant variability amongst different studies. Here, we report a simple and effective method for obtaining well-spread chromosomes from mammalian cells for the analysis of chromosomal aberrations. In this method, cells are (1) arrested in metaphase (when chromosome morphology is clearest), (2) swollen in hypotonic solution, (3) fixed before being dropped onto microscope slides, and (4) stained with DNA dyes to visualize the chromosomes. Metaphase chromosomes are then analyzed using high-resolution microscopy. We also provide examples, representative images, and useful guidelines to facilitate the scoring of the different chromosomal aberrations. This method can be used for the diagnosis of genetic diseases, as well as for cancer studies, by identifying chromosomal defects and providing insight into the cellular processes that influence chromosome integrity.

MEDICAL AND RADIOBIOLOGICAL ASPECTS OF RADIATION COMDPLICATIONS IN PATIENTS WITH ONCOGINECOLOGICAL PROFILE

Summary. Aim: to analyze the literature regarding the causes of the occurrence and features of distant complications of radiation therapy of cancer patients; investigation of the frequency and spectrum of spontaneous aberrations of chromosomes in the lymphocytes of peripheral blood of patients with oncogynecological profile (body cancer and cervix) before the onset of radiation therapy. Object and methods: peripheral blood lymphocyte test system with metaphase analysis of chromosome aberrations of 32 primary of cancer patients (follow-up group) and 30 conditionally healthy donors (comparison group). The examination of patients was performed before the onset of radiation therapy. Results: based on the analysis of literature data, the path to a personalized approach to the planning of radiation therapy for patients with oncogyne5 cological profile, the treatment of which is complicated by radiation lesions from the organs and tissues of the pelvis. The clinical and radiobiological aspects of the formation of radiation complications are considered in detail, the search for genetic indicators for the detection of patients with a high risk of developing radiation complications is justified. The results of cytogenetic examinations of patients with endometrial cancer and cervical cancer are close and indicate a 6-fold increase in the frequency of spontaneous chromosome aberrations compared to the population rate. In the spectrum of chromosomal restructures, complex restructures are recorded, which is uncharacteristic of the spontaneous level of aberration in healthy donors, as well as increased levels of chromatide type aberrations. Conclusions: the increased level of spontaneous chromosomal aberrations in T-lymphocytes of primary oncogynecological patients and the predominance of chromatid-type aberrations in the spectrum of registered chromosomal rearrangements indicate that genetic instability is formed in healthy cells before the start of radiation therapy, which predicts the risk of distant radiation complications, including the occurrence of secondary tumors radiation genesis. The examination of patients with the use of cytogenetic test will provide the most reasonable conclusion about the individual radio sensitivity of the patient to the onset of radiation therapy and will contribute to increasing its effectiveness, as well as improving the quality of life.

Clinical, immunological and genetic research on the participants in mitigating the consequences of the Chernobyl nuclear accident

Introduction. The paper presents the results of research on the influence of IR sources on the health of professionally and accidentally exposed personnel. Particular emphasis is placed on: identifying the relationships between the level of radiation dose and the development of oncological diseases; use of contemporary biological dosimetry methods for retrospective analysis of irradiation doses; the impact of parental irradiation on the health of the offspring; the structure of morbidity, including oncological diseases in patients exposed to IR sources.
 Material and methods. The study material was used by subjects professionally and accidentally exposed to IR sources: medical staff and PMCCNA born in the Republic of Moldova, Ukraine and the Russian Federation, as well as their descendants, victims of the accident at the Fukushima Daiichi nuclear power plant (Japan) and residents of the region. Chelyabinsk. Clinical, immunological and cytogenetic methods were used.
 Results. A wide range of mental pathologies was observed at PMCCNA, at the victims of the accident at the Fukushima Daiichi nuclear power plant, etc. The structure of immune deficiency syndromes was dominated by allergic and autoimmune syndromes. Based on the analysis of stable chromosomal aberrations, exposure doses were established.
 Conclusions. In the absence of dose information received by staff professionally/accidentally exposed to IR sources, assessment of stable chromosomal aberrations makes it possible to reconstruct the radiation dose for PMCCNA exposed to low doses of IR.

Replication stress drives chromosomal instability in fibroblasts of childhood cancer survivors with second primary neoplasms

New development and optimization of oncologic strategies are steadily increasing the number of long-term cancer survivors being at risk of developing second primary neoplasms (SPNs) as a late consequence of genotoxic cancer therapies with the highest risk among former childhood cancer patients. Since risk factors and predictive biomarkers for therapy-associated SPN remain unknown, we examined the sensitivity to mild replication stress as a driver of genomic instability and carcinogenesis in fibroblasts from 23 long-term survivors of a pediatric first primary neoplasm (FPN), 22 patients with the same FPN and a subsequent SPN, and 22 controls with no neoplasm (NN) using the cytokinesis-block micronucleus (CBMN) assay. Mild replication stress was induced with the DNA-polymerase inhibitor aphidicolin (APH). Fibroblasts from patients with the DNA repair deficiency syndromes Bloom, Seckel, and Fanconi anemia served as positive controls and for validation of the CBMN assay supplemented by analysis of chromosomal aberrations, DNA repair foci (γH2AX/53BP1), and cell cycle regulation. APH treatment resulted in G2/M arrest and underestimation of cytogenetic damage beyond G2, which could be overcome by inhibition of Chk1. Basal micronuclei were significantly increased in DNA repair deficiency syndromes but comparable between NN, FPN, and SPN donors. After APH-induced replication stress, the average yield of micronuclei was significantly elevated in SPN donors compared to FPN (p = 0.013) as well as NN (p = 0.03) donors but substantially lower than for DNA repair deficiency syndromes. Our findings suggest that mild impairment of the response to replication stress induced by genotoxic impacts of DNA-damaging cancer therapies promotes genomic instability in a subset of long-term cancer survivors and may drive the development of an SPN. Our study provides a basis for detailed mechanistic studies as well as predictive bioassays for clinical surveillance, to identify cancer patients at high risk for SPNs at first diagnosis.

Acquired Loss of a Sex Chromosome Is a Positive Prognostic Factor for Patients with Multiple Myeloma Undergoing ASCT

Introduction: In patients with multiple myeloma (MM), small somatic genetic lesions in non-malignant blood cells, i.e. clonal hematopoiesis, has been found to be associated with inferior survival and other adverse outcomes (Mouheddine T.H. et al. - Nature Comm. 2020). However, large-scale alterations on a chromosomal level are also acquired in ageing blood cells and may impact patient outcomes. Methods: Using a novel bioinformatic approach, we performed a genome-wide analyses of chromosomal aberrations in 998 patients with multiple myeloma before undergoing autologous stem cell transplant (ASCT) in a national population-based cohort. Post-induction harvest samples were analyzed with a custom Illumina deCODE Genetics SNP array and further processed using MoChA bioinformatic pipeline (Loh P., Genovese G. et al. - Nature 2020) to identify acquired mosaic chromosomal alterations (mCAs). Comprehensive clinical data was collected from nationwide registries with long-term follow-up (the Danish Multiple Myeloma Registry and the Danish Civil Registration System). Data included information on diagnostic criteria, peripheral blood counts, M protein, β-2 microglobulin, albumin, genetic myeloma aberrations by FISH, treatment, response to ASCT, progression, and death. Results: We identified 178 patients (17.8%) with acquired chromosomal alterations before undergoing ASCT. Autosomal mCAs were identified in 77 patients (7.7%), while 109 patients (10.9%) had loss of sex chromosomes (X or Y). Alterations were found on all chromosomes. Median cell fraction of autosomal mCA clones was 6.6% (IQR 2.7-20.4) in the analyzed harvest samples. Loss of sex chromosome was strongly associated with higher age (Wilcoxon P < 0.0001), while the age association was less robust for autosomal mCAs (Wilcoxon P = 0.094). There was no impact of type of induction regimen on frequency of mCAs. Full clinical annotation was available for 799 patients. Median follow-up was 6.4 years. Interestingly, at MM diagnosis, bone marrow plasma cell infiltration was significantly lower in patients with loss of chromosome X or Y (β coefficient -9.1%, P = 0.003). In accordance, hemoglobin level at diagnosis was also significantly higher in patients with sex chromosome loss (P = 0.027), despite these patients being older. In addition, the response to ASCT was superior in patients with loss of a sex chromosome. In patients that obtained at least a very good partial response after ASCT, 12.9% had sex chromosome loss, while only 4.7% of patients with poorer responses had sex chromosome loss (chi-square test P = 0.0017). In relation to these findings, overall survival was found to be superior in patients with loss of chromosome X, also when adjusted for age and sex (adj.P = 0.02). This survival difference was however only observed for long-term survivors (after more than four years of follow-up), indicating a possible interaction with later treatments. On the contrary, detection of multiple autosomal mCAs (n=14 patients) was associated with early age-independent inferior survival (adj.P = 0.005). A single autosomal mCA did not affect overall survival. To identify possible infiltration of malignant cells in the stem cell harvest, in a subset of patients (n=360) we were able to cross-check mCAs with FISH data on chromosomal variants identified in CD138+ sorted myeloma cells. We found no overlap between common myeloma chromosomal aberrations by FISH and identified mCAs. This indicates that the identified mCAs are from cells of the non-malignant hematopoietic system and not from myeloma plasma cells. Conclusion: In a longitudinal nationwide cohort of MM patients we examined the impact of acquired hematopoietic chromosomal alterations. Somatic mCAs or loss of sex chromosome was detected in stem cell harvest material in almost one fifth of patients undergoing ASCT. Sex chromosome loss was significantly associated with higher age, but surprisingly, it was also significantly associated with better response to ASCT and longer overall survival. The underlying biological causes of these findings remain to be elucidated. With regards to clonal origins, we did not identify any chromosomal variants to be present in both the myeloma clone (by diagnostic CD138+ FISH) and in the harvest product (by mCA analysis) in the same patient.

The Chemical Composition and Antimitotic, Antioxidant, Antibacterial and Cytotoxic Properties of the Defensive Gland Extract of the Beetle, Luprops tristis Fabricius.

The unpredictable invasion of the Mupli beetle, Luprops tristis Fabricius (Coleoptera: Tenebrionidae), makes areas uninhabitable to humans. These beetles produce a strong-smelling, irritating secretion as a defence mechanism, which causes blisters on contact with human skin. In the current study, gas chromatography high-resolution mass spectrometry (GC-HRMS) analysis of the defensive gland extract of the Mupli beetle revealed the presence of compounds such as 2,3,dimethyl-1,4-benzoquinone, 1,3-dihydroxy-2-methylbenzene, 2,5-dimethyl hydroquinone, tetracosane, oleic acid, hexacosane, pentacosane, 7-hexadecenal and tert-hexadecanethiol. The defensive gland extracts showed considerable antibacterial activity on Gram-negative and Gram-positive bacteria in an agar diffusion assay. The chromosomal aberration analysis using root tips of Allium cepa L. exposed to the defensive secretion showed chromosomal aberrations such as disturbed metaphase, sticky chromosomes and chromosomal breakage. The antioxidant activity of the extract was determined using a radical scavenging (DPPH) assay. A cytotoxic assay of the defensive gland extract against Dalton's lymphoma ascites (DLA) cell line showed anticancer properties. In the present study, the defensive gland extract of the Mupli beetle, L. tristis, which is generally perceived as a nuisance insect to humans, was found to have beneficial biological activities.

Medical personnel occupationally exposed to low-dose ionising radiation in Federation of Bosnia and Herzegovina: A cytogenetic study.

Medical radiation exposures have been reduced significantly with modern equipment and protection measures. Biomonitoring of medical personnel can provide information concerning possible effects of radiation exposure. However, chromosome aberration (CA) analysis is now recommended only when the estimated effective dose is 200 mSv or higher. In this retrospective study in Bosnia and Herzegovina, we have measured the cytogenetic status of medical workers and healthy volunteers (controls). Peripheral blood samples from 66 medical workers exposed to low-dose ionising radiation and 89 non-exposed volunteers were collected for chromosome aberrations (CA) analysis and the cytokinesis-block micronucleus (CBMN) assay. Higher rates of chromatid and chromosome breaks, acentric fragments, double minutes, micronuclei, and micronucleated binuclear cells were observed in the control group, while the rate of nucleoplasmic bridges was higher in the medical workers group.

Fluorescence in situ hybridization analysis of chromosomal aberrations in mouse splenocytes at one- and two-months after total body exposure to iron-56 (Fe) ion particles or X-rays.

High atomic number and energy (HZE) particles such as iron-56 (Fe) ions are a major contributor to health risks in long-term manned space exploration. The aim of this study is to understand radiation-induced differential genotoxic effects between HZE particles and low linear energy transfer (LET) photons. C57BL/6J Jms female mice of 8 weeks old were exposed to total body irradiation of accelerated Fe-particles with a dose ranging from 0.1 to 3.0Gy or of X-rays with a dose ranging from 0.1 to 5.0Gy. Chromosomal aberrations (CAs) in splenocytes were examined by fluorescence in situ hybridization at 1- and 2-months after exposure. Clonal expansions of cells with CAs were found to be induced only by X-rays but not by Fe-particles. Dose-dependent increase in the frequencies of stable-type CAs was observed at 1- as well as 2-months after exposure to both radiation types. The frequencies of stable-type CAs in average were much higher in mice exposed to X-rays than those to Fe-particles and did not change significantly between 1- and 2-months after exposure to both radiation types. On the other hand, the frequencies of unstable-type CAs induced by X-rays and Fe-particles were not much different, and they appeared to decrease with time from 1- to 2-months after exposure. These results suggested that larger fraction of stable-type CAs induced by Fe-particles might be non-transmissible than those by X-rays because of some associating lethal alterations on themselves or on other chromosomes in the same cells and that these cells might be removed by 1-month after Fe-TBI. We also demonstrated that exposure to Fe-particles induced insertions at relatively higher frequency to other stable-type CAs than X-rays. Our findings suggest that insertions can be used as indicators of past exposure to high-LET particle radiation.

Metaphase Chromosome Preparation and Classification of Chromosomal Aberrations.

Chromosomal aberrations are changes in structure and number of chromosomes. Metaphase chromosome can be analyzed by a standard light microscope to detect chromosomal aberrations. Recently, detailed analysis or rapid analysis was possible by using fluorescence probes and fluorescent microscope. The origins of chromosomal aberrations can be errors of DNA repair, cell divisions, and DNA synthesis. Analysis of chromosome aberrations can be used for the wide range of analysis. It includes a basic science connecting DNA damage to cellular death and mutagenesis and diagnostic tools for hereditary diseases and biodosimetry following radiation exposure.Specific DNA damages produce unique types of chromosomal aberrations. Analysis of chromosomal aberrations enables us to investigate the mechanisms of genotoxic stress. However, one type of DNA damage provides a variety of changes in chromosome structures. It is often confusing. This chapter introduces the standard technique of metaphase chromosome spread preparation and typical classification of chromosomal aberrations.

Cytokinesis Blocked Micronuclei Aberration Analysis.

Cytokinesis blocked micronuclei (CBMN) assay is a rapid and sensitive analysis of chromosome aberrations and miss assortments during cell division. Genotoxic agent exposure produces DNA damage and chromosome fragments. Fragmented chromosomes without centromere failed to attach kinetochore which segregates a pair of homologous chromosomes to each daughter cells at cytokinesis, hence leading to form micronuclei. Chromosome or fragments of chromosome can also form micronuclei when they are not accurately sorted to daughter cells. Using cytochalasin B, an actin inhibitor, blocks cytokinesis of which completion leads serration appearance formed with two daughter cells while nuclei segregation is undergoing. As a result, one cell having two daughter nuclei, i.e., binucleated cell, is produced. By analyzing these binucleated cells, chromosome aberrations can be estimated as well as popular chromosome aberration analysis. Frequency of micronuclei formation predicts the testing agents' genotoxicity. By combining use with centromere-specific probes or DNA damage signal probes, the nature of genotoxicity of tested agents can be estimated.

Chromosomal damage in occupationally exposed health professionals assessed by two cytogenetic methods

The study assessed occupationally induced chromosomal damage in hospital personnel at risk of exposure to antineoplastic drugs and/or low doses of ionizing radiation by two cytogenetic methods. Cultured peripheral blood lymphocytes of eighty-five hospital workers were examined twice over 2 to 3 years by classical chromosomal aberration analysis and fluorescence in situ hybridization. The comparison of the 1st and the 2nd sampling of hospital workers showed a significant increase in chromatid and chromosomal aberrations (all p < .05) examined by classical chromosomal aberration analysis, and in unstable aberrations (all p < .05) detected by fluorescence in situ hybridization. Both cytogenetic methods were able to detect an increase of unstable aberrations in the 2nd sampling. The raised frequency of unstable cytogenetic parameters suggested higher recent exposure to genotoxic agents.

Cytogenetic and epigenetic aberrations in peripheral lymphocytes of northwest Arkansas Marshallese

Purpose Nuclear weapons testing in the northern Marshall Islands between 1946 and 1958 resulted in ionizing radiation (IR) exposure of the thousands of Marshallese. Furthermore, numerous islands were contaminated by radioactive fallout. Significant increases in cancer and metabolic syndrome incidences have been reported among Marshallese, and potential for further increases looms due to the latency of radiation-induced health effects. The purpose of this study was to investigate the genetic and epigenetic effects of exposure to IR that could be associated with radiation-induced disease among the Northwest Arkansas (NWA) Marshallese. Materials and Methods We performed analysis of chromosomal aberrations and DNA methylation based on residential and exposure history of NWA Marshallese. Results Analysis of chromosomal aberrations demonstrated higher incidence of genetic rearrangements in women with self-reported history of radiation exposure (95% CI: 0.10, 1.22; p=.022). Further clustering of study participants based on their residential history demonstrated that participants who spent substantial amounts of time (≥6 months) in the northern atolls (thus, in the proximity of nuclear tests) before 1980 had more chromosomal aberrations than their peers who lived only in the southern atolls (95% CI: 0.08, −0.95; p=.021), and that this difference was driven by women. A relationship between the time spent in the northern atolls and increase in chromosomal aberrations was observed: 0.31 increase in chromosomal aberrations for every 10 years spent at northern atolls (95% CI: 0.06, 0.57; p=.020). Finally, significant inverse correlations between the chromosomal aberrations and the extent of DNA methylation of four LINE-1 elements L1PA2, L1PA16, L1PREC1, and L1P4B were identified. Conclusions The results of this study provide first evidence of the presence of stable genetic and epigenetic rearrangements in peripheral lymphocytes of NWA Marshallese and warrant further studies to analyze the role of radiation exposure in health disparities experienced by this Pacific Island nation.

Occurrence of cytogenetic effects under the action of epimutagen in winter wheat

Research on studying the features of 0.01%, 0.05%, 0.10% and 0.50% epimutagen Triton-X-305 impact at the cellular level, which means the way of identifying the viability of pollen in plants of the first generation, and cytological analysis of chromosomal aberrations in the cells of the primary meristem of germinal roots during germination of bread winter wheat seeds have been conducted. Research in this direction allows us to significantly improve the monitoring of same type of substances in the environment and to forecast the nature of their action at the DNA-level. Genotypes Podolyanka and Spivanka created by Ukrainian selection and varieties of French selection Altigo, Courtot, Lyrik, Flamenko have been studied. These genotypes were selected in order to characterize possible genotype-mutagenic interactions for a compound of complex hereditary pattern for a range of concentrations with maximum contrast taking into account the possible high site-specific effect. The main purpose of this research was to identify the specificity of impact of the agent Triton X-305 at the cellular level and identify parameters fully showing the effect of this substance on the subsequent induction of biodiversity and the enhancement of hereditary variability at the cellular level. Such indicators as pollen sterility effected by various concentrations, the total frequency of chromosomal rearrangements, the spectrum of chromosomal rearrangements, including fragments and double fragments, single and double bridges, micronuclei and lagging chromosomes have been investigated. The ratio of fragments to bridges as an indicator of the active factor nature, the number of cells with two or more rearrangements as an indicator of genetic toxicity of this substance has been established. As a result, a significantly weaker effect of the epimutagen on the overall frequency of chromosomal rearrangement has been shown unlike other factors of a mutagenic nature, at the same time changing the ratio of the obtained aberrations in favour of micronuclei and lagging chromosomes. In addition, other parameters are determined as more meaningful for identifying a specific agent of impact, and the differences in concentrations are less contrasting. There is also a less significantly decreasing fertility, however, this parameter is highly dependent on the source material. In the future, we intend to assess the variability, primarily of a hereditary nature, by the way of a visual analysis of the obtained material in subsequent generations, as well as through biochemical analysis, yield qualities analysis and morphometry of the obtained material.

Study of Low-Dose Radiation Workers Ionizing Radiation Sensitivity Index and Radiation Dose-Effect Relationship.

In the present study, we analyzed radiation injuries to Chinese workers exposed to low-dose radiation. We discuss the relationships between dose and injury. This study randomly selected 976 radiation workers who underwent occupational health monitoring. The radiation workers were divided into 5 different types of work: radiation diagnosis, radiation therapy, interventional therapy, nuclear medicine, and industrial inspection. This research was approved by the Bioethics Committee at the Gansu Provincial Center for Disease Control and Prevention. The average annual cumulative dose to interventional radiation workers was the highest, i.e., 0.86 mSv. The detection rate of lens opacity was 37%, but 99.70% of lens opacities occurred in the peripheral cortex. Posterior subcapsular opacification was detected less than 1.00% of the time. The rate of chromosomal aberrations was highest for radiological workers with more than 20 years of service. Annual cumulative dose reached 2.04 mSv, and the monitoring dose for 3 months was as high as 1.62 mSv. Dicentric chromosomes were also detected. The manual packaging and drug delivery nuclear medicine staffs totaled 14 individuals. 131 131 was detected in the thyroids of 4 workers (28.57%). The detection rate of thyroid 131 I was higher in the hand-packed and administered group than in the automatic administration group. Radiation workers exposed to low doses of radiation can sustain injuries. Interventional radiology workers receive the highest doses and sustain the most significant effects. This study suggests that chromosome aberration analysis is an important index in occupational health monitoring of radiological workers. Monitoring of internal radiation exposure cannot be ignored for nuclear medicine staff.

Impact of 11q Loss of Heterozygosity Status on the Response of High-Risk Neuroblastoma With MYCN Amplification to Neoadjuvant Chemotherapy.

PurposeThe aim of this study was to investigate whether 11q loss of heterozygosity (LOH) aberration would impact the response of the primary tumor to neoadjuvant chemotherapy or to the degree of surgical resection in neuroblastoma (NB) patients with MYCN amplification.MethodsThe clinical data of 42 NB patients with MYCN amplification who were newly diagnosed and received treatments at our hospital from 2011 to 2020 were retrospectively analyzed. According to the results of the segmental chromosome aberration analysis, the patients enrolled were assigned to an 11qLOH positive group and an 11qLOH negative group.ResultsThere was no significant difference in the mean number of chemotherapy courses completed before surgery between the 11qLOH positive and 11qLOH negative groups (p = 0.242). Each of the 42 patients had metaiodobenzylguanidine (MIBG) scans both before and after neoadjuvant chemotherapy. The percentage of patients who had a clinical MIBG change in the 11qLOH positive group was lower than the percentage in the 11qLOH negative group (27.27 vs. 66.67%, p = 0.030). The 11qLOH negative group seemed to have a higher rate of surgical resection (≥90%); however, the difference between the two groups was not statistically significant (p = 0.088). Furthermore, the 11qLOH negative group did not show significantly superior event-free survival and overall survival rates compared with the 11qLOH positive group.ConclusionsThis study showed that patients with NB and MYCN amplification in combination with 11qLOH might be less likely to respond to neoadjuvant chemotherapy when compared with patients with NB and MYCN amplification without 11qLOH.

First application of the BIANCA biophysical model to carbon-ion patient cases

Objective. The main objective of this work consists of applying, for the first time, the BIANCA (BIophysical ANalysis of Cell death and chromosome Aberrations) biophysical model to the RBE calculation for C-ion cancer patients, and comparing the outcomes with those obtained by the LEM I model, which is applied in clinics. Indeed, the continuous development of heavy-ion cancer therapy requires modelling of biological effects of ion beams on tumours and normal tissues. The relative biological effectiveness (RBE) of heavy ions is higher than that of protons, with a significant variation along the beam path. Therefore, it requires a precise modelling, especially for the pencil-beam scanning technique. Currently, two radiobiological models, LEM I and MKM, are in use for heavy ions in scanned pencil-beam facilities. Approach. Utilizing an interface with the FLUKA Particle Therapy Tool, BIANCA was applied to re-calculate the RBE-weighted dose distribution for carbon-ion treatment of three patients (chordoma, head-and-neck and prostate) previously irradiated at CNAO, where radiobiological optimization was based on LEM I. The predictions obtained by BIANCA were based either on chordoma cell survival (RBE surv ), or on dicentric aberrations in peripheral blood lymphocytes (RBE ab ), which are indicators of late normal tissue damage, including secondary tumours. The simulation outcomes were then compared with those provided by LEM I. Main results. While in the target and in the entrance channel BIANCA predictions were lower than those obtained by LEM I, the two models provided very similar results in the considered OAR. The observed differences between RBE surv and RBE ab (which were also dependent on fractional dose and LET) suggest that in normal tissues the information on cell survival should be integrated by information more closely related to the induction of late damage, such as chromosome aberrations. Significance. This work showed that BIANCA is suitable for treatment plan optimization in ion-beam therapy, especially considering that it can predict both cell survival and chromosome aberrations and has previously shown good agreement with carbon-ion experimental data.

Radiobiological damage by space radiation: extension of the BIANCA model to heavy ions up to iron, and pilot application to cosmic ray exposure

Space research seems to be object of a renewed interest, also considering that human missions to the Moon, and possibly Mars, are being planned. Among the risks affecting such missions, astronauts’ exposure to space radiation is a major concern. In this work, the question of the evaluation of biological damage by Galactic Cosmic Rays (GCR) was addressed by a biophysical model called BIophysical ANalysis of Cell death and chromosome Aberrations (BIANCA), which simulates the induction of cell death and chromosome aberrations by different ions. While previously BIANCA has been validated for calculating cell death along hadrontherapy beams up to oxygen, herein the approach was extended up to Fe ions. Specifically, experimental survival curves available in literature for V79 cells irradiated by Si-, Ne-, Ar- and Fe-ions were reproduced, and a reference radiobiological database describing V79 cell survival as a function of ion type (1 ⩽ Z ⩽ 26), energy and dose was constructed. Analogous databases were generated for Chinese hamster ovary hamster cells and human skin fibroblasts, finding good agreement between simulations and data. Concerning chromosome aberrations, which are regarded as radiation risk biomarkers, dicentric data in human lymphocytes irradiated by heavy ions up to iron were reproduced, and a radiobiological database allowing calculation of lymphocyte dicentric yields as a function of dose, ion type (1 ⩽ Z ⩽ 26) and energy was constructed. Following interface between BIANCA and the FLUKA Monte Carlo transport code, a feasibility study was performed to calculate the relative biological effectiveness (RBE) of different GCR spectrum components, for both dicentrics and cell death. Fe-ions, although representing only 10% of the total absorbed dose, were found to be responsible for about 35%–40% of the RBE-weighted dose. Interestingly, the RBE for dicentrics was higher than that for cell survival. More generally, this work shows that BIANCA can calculate RBE values for cell death and lymphocyte dicentrics not only for ion therapy, but also for space radiation.

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.

Detection and identification of hazardous organic pollutants from distillery wastewater by GC-MS analysis and its phytotoxicity and genotoxicity evaluation by using Allium cepa and Cicer arietinum L.

Distillery industry generates a huge amount of wastewater, which contains a high strength of organic and inorganic load. Accordingly, this study aims to analyze the physico-chemical pollution parameters and the occurrence of phytotoxic, cytotoxic and genotoxic pollutants in wastewater. The result revealed that values of wastewater parameters were recorded as 13268 mg l−1 (BOD), 25144 mg l−1 (COD), 25144 mg l−1 (TS), and 6634 mg l−1 (phosphate), while pH was alkaline. The organic compounds detected by GC-MS were quercetin 7,3′,4′-trimethoxy, octadecadienoic acid, propanoic acid, glycocholic acid methyl ester, cantaxanthin, etc. The Allium cepa was used for the toxicity test with different concentrations of wastewater showed a significant level of reduction in root growth and length after exposure and the maximum reduction was at 25% and 20%. Phytotoxicity studies were performed using Cicer arietinum L. with different concentrations of wastewater, which showed adverse effects on seed germination, root length, and the effect was associated with the increasing concentration of wastewater. A. cepa root tips were used for the analysis of mitotic index (MI), nuclear abnormalities (NA), and chromosomal aberrations (CA). MI was decreasing significantly from 72% (control) to 33%, 22%, 23%, 21%, and 18% at 5%, 10%, 15%, 20%, and 25% wastewater concentration, respectively. The A. cepa root tip cells showed chromosomal aberrations and nuclear abnormalities like vagrant, stickiness, chromosomal loss, c-mitosis, binucleated, micronuclei, and aberrant cell. This study concluded that the wastewater treatment process is insufficient and the discharged waste needs a proper assessment to know the associated health risk.

Cytogenotoxicity of the aqueous extract of Parquetina nigrescens leaf using Allium cepa assay.

Parquetina nigrescens has been used for decades in ethnomedicine for its antioxidant, antimicrobial, anti-inflammatory, analgesic, and aphrodisiac properties. In this study, the cytotoxic and genotoxic effect of aqueous crude leaf extracts of P. nigrescens on the root meristematic cells of Allium cepa was examined. Volatile organic compounds (VOCs) present in the plant extract were also identified using gas chromatography-mass spectrometry (GC-MS). The extract was prepared with tap water as is locally practised by many Nigerians. Onion bulbs were exposed to 1, 5, 10, 20, and 50% concentrations of the extract for the analysis of root growth inhibition and chromosomal aberration. Lead nitrate (10ppm) and tap water were used as the positive and negative controls, respectively. The result showed cytotoxicity which was observed as statistically significant (p <p0.05), concentration-dependent inhibition of root growth from 5 to 50% concentrations of the plant extract compared with the negative control. At 10 and 20% concentrations, the extract showed statistically significant (p < 0.05) genotoxicity by inducing different chromosomal aberrations such as fragments, disturbed spindle, delayed, and sticky chromosomes. The GC-MS analysis identified 14 VOCs of which 1, 2-benzenediol, 4H-pyran-4-one, 2, 3-dihydro-3,5-dihydroxy-6-methyl, and 5-hydroxymethylfurfural were believed to be responsible for the observed cytogenotoxicity. These results show that the aqueous crude leaf extracts of P. nigrescens at high concentrations are cytogenotoxic and therefore should be consumed with caution.