On- and off-target effects of paired CRISPR-Cas nickase in primary human cells.

Undesired on- and off-target effects of CRISPR-Cas nucleases remain a challenge in genome editing. While the use of Cas9 nickases has been shown to minimize off-target mutagenesis, their use in therapeutic genome editing has been hampered by a lack of efficacy. To overcome this limitation, we and others have developed double-nickase-based strategies to generate staggered DNA double-strand breaks to mediate gene disruption or gene correction with high efficiency. However, the impact of paired single-strand nicks on genome integrity has remained largely unexplored. Here, we developed a novel CAST-seq pipeline, dual CAST, to characterize chromosomal aberrations induced by paired CRISPR-Cas9 nickases at three different loci in primary keratinocytes derived from patients with epidermolysis bullosa. While targeting COL7A1, COL17A1, or LAMA3 with Cas9 nucleases caused previously undescribed chromosomal rearrangements, no chromosomal translocations were detected following paired-nickase editing. While the double-nicking strategy induced large deletions/inversions within a 10 kb region surrounding the target sites at all three loci, similar to the nucleases, the chromosomal on-target aberrations were qualitatively different and included a high proportion of insertions. Taken together, our data indicate that double-nickase approaches combine efficient editing with greatly reduced off-target effects but still leave substantial chromosomal aberrations at on-target sites.

Next-generation cytogenetics: Comprehensive assessment of 52 hematological malignancy genomes by optical genome mapping.

Somatic structural variants (SVs) are important drivers of cancer development and progression. In a diagnostic set-up, especially for hematological malignancies, the comprehensive analysis of all SVs in a given sample still requires a combination of cytogenetic techniques, including karyotyping, FISH, and CNV microarrays. We hypothesize that the combination of these classical approaches could be replaced by optical genome mapping (OGM). Samples from 52 individuals with a clinical diagnosis of a hematological malignancy, divided into simple (<5 aberrations, n = 36) and complex (≥5 aberrations, n = 16) cases, were processed for OGM, reaching on average: 283-fold genome coverage. OGM called a total of 918 high-confidence SVs per sample, of which, on average, 13 were rare and >100 kb. In addition, on average, 73 CNVs were called per sample, of which six were >5 Mb. For the 36 simple cases, all clinically reported aberrations were detected, including deletions, insertions, inversions, aneuploidies, and translocations. For the 16 complex cases, results were largely concordant between standard-of-care and OGM, but OGM often revealed higher complexity than previously recognized. Detailed technical comparison with standard-of-care tests showed high analytical validity of OGM, resulting in a sensitivity of 100% and a positive predictive value of >80%. Importantly, OGM resulted in a more complete assessment than any previous single test and most likely reported the most accurate underlying genomic architecture (e.g., for complex translocations, chromoanagenesis, and marker chromosomes). In conclusion, the excellent concordance of OGM with diagnostic standard assays demonstrates its potential to replace classical cytogenetic tests as well as to rapidly map novel leukemia drivers.

Combined first-trimester screening and invasive diagnostics for atypical chromosomal aberrations: Danish nationwide data on prenatal profiles and detection compared with NIPT.

OBJECTIVE: To examine the prenatal profiles of pregnancies affected by an atypical chromosomal aberration, focusing on pathogenic copy number variants (pCNVs). Further, we wanted to quantify the performance of combined first-trimester screening (cFTS) and a second-trimester anomaly scan in detecting these conditions. Finally, we aimed to estimate the consequences of a policy of using non-invasive prenatal testing (NIPT) rather than invasive testing with chromosomal microarray (CMA) to manage pregnancies identified as high risk from cFTS. METHODS: A retrospective review of the Danish fetal medicine database identified all pregnant women who had cFTS and a trisomy 21 risk-assessment between January 1, 2008, and December 31, 2018. Chromosomal aberrations diagnosed prenatally, postnatally, or from fetal tissue following pregnancy loss or termination of pregnancy (TOP) were identified. Chromosomal aberrations were grouped into one of six categories: 1) Triploidy; 2) Common trisomies (trisomies 21, 18, and 13); 3) Monosomy X; 4) Other sex chromosome aberrations (SCAs); 5) pCNVs; and 6) Rare autosomal trisomies (RATs) and mosaicisms. The prevalence of each aberration-category was stratified by the individual cFTS markers and risk estimate, and the size of each pCNV diagnosed from CMA was calculated. RESULTS: We included data on 565,708 pregnancies of which 3,982 were diagnosed with a fetal chromosomal aberration (0.70%). cFTS performed well in identifying triploidies (86%), monosomy X (92%), atypical SCAs (58%), and RATs and mosaicisms (70%). pCNVs comprised 28% (n = 1,091) of the chromosomal aberrations diagnosed overall, and the prevalence increased during the study period with more prenatal chromosomal microarray analysis being performed. In pregnancies with maternal age <30 years, NT <95th percentile, PAPP-A MoM ≥ 1, or trisomy 21 risk ≥1 in 1000, the prevalence of pCNVs significantly exceeded the prevalence of trisomies 21, 18, and 13. Pregnancies affected by a pCNV had significantly increased nuchal translucency thickness (NT) and decreased maternal biomarkers pregnancy associated plasma protein-A (PAPP-A) and ß-human chorionic gonadotropin (ß-hCG) compared with unaffected pregnancies. However, only 23% of these pregnancies screened positive from cFTS and 51% were not detected until after birth. Amongst high-risk pregnancies diagnosed with a chromosomal aberration, pCNVs comprised 14% and when other atypical aberrations were considered, conventional NIPT (screening for trisomies 21, 18, and 13, and monosomy X) would miss 28% of all pathogenic aberrations diagnosed following a high-risk cFTS result. Thus, 1 in 26 pregnancies at high-risk following cFTS would be affected by a chromosomal aberration despite a normal conventional NIPT result. In a contingent screening model with NIPT provided for the "intermediate" risk group (T21 risk of 1 in 100-300), 50% of the aberrations would be missed. In our cohort, 80% of the pCNVs diagnosed were <5Mb and therefore not detectable using current forms of "genome wide" NIPT. CONCLUSION: As a by-product to screening for trisomies 21, 18, and 13, most triploidies and the majority of atypical SCAs, RATs, and mosaicisms are detected before birth. However, only 23% of pCNVs are high-risk from cFTS and only half are diagnosed before birth. Replacing invasive testing with NIPT for high-risk pregnancies would substantially decrease the first-trimester detection of pathogenic chromosomal anomalies. This article is protected by copyright. All rights reserved.

Model of age-dependent dynamics and biokinetics of T-cells as natural biodosimeters.

Circulating T-lymphocytes are used as "natural biodosimeters" for estimating radiation doses, since the frequency of chromosomal aberrations induced in them is proportional to the accumulated dose. Moreover, stable chromosomal aberrations (translocations) are detected years and decades after exposure. Internal incorporation of radionuclides often leads to non-uniform exposure, which resulted in difficulties in the application of retrospective biodosimetry using T-lymphocytes. Some properties of T-lymphocytes complicate retrospective biodosimetry in this case: (1) the thymic production of T-cells depends significantly on age, the maximum is observed in early childhood; (2) the "lymphocyte-dosimeter" accumulates changes (translocations) while circulating through the body. The objective of this paper is to describe the technical characteristics of the model of age dynamics and T-cell biokinetics and approaches to assessing the dose to circulating lymphocytes under various exposure scenarios. The model allows to quantify the fractions of T-lymphocytes that were formed before and after exposure. The model takes into account the time fractions that circulating lymphocytes spend in various lymphoid organs. Age-related thymic involution was also considered. The model predicts that after internal exposure to 90Sr, the doses to T-lymphocytes can differ significantly from the doses to the bone marrow and other tissues. For uniform external γ-exposure, and for internal exposure due to non-bone -seeking radionuclides (for example, 144Ce), predicted doses to T-lymphocytes are very close to bone marrow doses. The model allows to quantify the correction factors for FISH-based doses to obtain doses to organs and tissues.

Evaluation of oxidative stress and genetic instability among residents near mobile phone base stations in Germany.

Human exposure to radiofrequency electromagnetic fields (RF-EMF) is restricted to prevent thermal effects in the tissue. However, at very low intensity exposure "non-thermal" biological effects, like oxidative stress, DNA or chromosomal aberrations, etc. collectively termed genomic-instability can occur after few hours. Little is known about chronic (years long) exposure with non-thermal RF-EMF. We identified two neighboring housing estates in a rural region with residents exposed to either relatively low (control-group) or relatively high (exposed-group) RF-EMF emitted from nearby mobile phone base stations (MPBS). 24 healthy adults that lived in their homes at least for 5 years volunteered. The homes were surveyed for common types of EMF, blood samples were tested for oxidative status, transient DNA alterations, permanent chromosomal damage, and specific cancer related genetic markers, like MLL gene rearrangements. We documented possible confounders, like age, sex, nutrition, life-exposure to ionizing radiation (X-rays), occupational exposures, etc. The groups matched well, age, sex, lifestyle and occupational risk factors were similar. The years long exposure had no measurable effect on MLL gene rearrangements and c-Abl-gene transcription modification. Associated with higher exposure, we found higher levels of lipid oxidation and oxidative DNA-lesions, though not statistically significant. DNA double strand breaks, micronuclei, ring chromosomes, and acentric chromosomes were not significantly different between the groups. Chromosomal aberrations like dicentric chromosomes (p=0.007), chromatid gaps (p=0.019), chromosomal fragments (p<0.001) and the total of chromosomal aberrations (p<0.001) were significantly higher in the exposed group. No potential confounder interfered with these findings. Increased rates of chromosomal aberrations as linked to excess exposure with ionizing radiation may also occur with non-ionizing radiation exposure. Biological endpoints can be informative for designing exposure limitation strategies. Further research is warranted to investigate the dose-effect-relationship between both, exposure intensity and exposure time, to account for endpoint accumulations after years of exposure. As established for ionizing radiation, chromosomal aberrations could contribute to the definition of protection thresholds, as their rate reflects exposure intensity and exposure time.

Assessment of genotoxicity biomarkers in gasoline station attendants due to occupational exposure.

Gasoline station attendants are exposed to numerous chemicals that might have genotoxic and carcinogenic potential, such as benzene in fuel vapor and particulate matter and polycyclic aromatic hydrocarbons in vehicle exhaust emission. According to IARC, benzene and diesel particulates are Group 1 human carcinogens, and gasoline has been classified as Group 2A "possibly carcinogenic to humans." At gas stations, self-service is not implemented in Turkey; fuel-filling service is provided entirely by employees, and therefore they are exposed to those chemicals in the workplace during all working hours. Genetic monitoring of workers with occupational exposure to possible genotoxic agents allows early detection of cancer. We aimed to investigate the genotoxic damage due to exposures in gasoline station attendants in Turkey. Genotoxicity was evaluated by the Comet, chromosomal aberration, and cytokinesis-block micronucleus assays in peripheral blood lymphocytes. Gasoline station attendants (n = 53) had higher tail length, tail intensity, and tail moment values than controls (n = 61). In gasoline station attendants (n = 46), the frequencies of chromatid gaps, chromosome gaps, and total aberrations were higher compared with controls (n = 59). Increased frequencies of micronuclei and nucleoplasmic bridges were determined in gasoline station attendants (n = 47) compared with controls (n = 40). Factors such as age, duration of working, and smoking did not have any significant impact on genotoxic endpoints. Only exposure increased genotoxic damage in gasoline station attendants independently from demographic and clinical characteristics. Occupational exposure-related genotoxicity risk may increase in gasoline station attendants who are chronically exposed to gasoline and various chemicals in vehicle exhaust emissions.

Enhancement of the Clastogenic Effects of Topotecan In Vivo by Tyrosyl-DNA Phosphodiesterase 1 Inhibitors.

Topotecan administered intraperitoneally at single doses of 0.25, 0.5, and 1 mg/kg induced chromosomal aberrations in bone marrow cells of F1(CBA×C57BL/6) hybrid mice in a dose-dependent manner. A tyrosyl-DNA phosphodiesterase 1 (TDP1) inhibitor, an usnic acid derivative OL9-116 was inactive in a dose range of 20-240 mg/kg, but enhanced the cytogenetic effect of topotecan (0.25 mg/kg) at a dose of 40 mg/kg (per os). The TDP1 inhibitor, a coumarin derivative TX-2552 (at doses of 20, 40, 80, and 160 mg/kg per os), increased the level of aberrant metaphases induced by topotecan (0.25 mg/kg) by 2.1-2.6 times, but was inactive at a dose of 10 mg/kg. The results indicate that TDP1 inhibitors enhance the clastogenic activity of topotecan in mouse bone marrow cells in vivo and are characterized by different dose profiles of the co-mutagenic effects.

Chromosome-1 abnormalities in Childhood B-Lymphoblastic Leukemia - An analysis with reference to clinical variables and survival outcome.

Background: Chromosome-1 abnormalities (C1As) are common genetic aberrations in hematological malignancies. We sought to evaluate significance of these abnormalities with reference to clinical characteristics and survival outcome in a pediatric B-Lymphoblastic Leukemia (B-ALL) cohort. Methods: This is a retrospective study conducted in cytogenetic section of Indus Hospital and Health Network. Data was retrieved from October 2020 to July 2022 for childhood B-ALL cases exhibiting C1As. Chromosome analysis was performed on Cytovision MB8 using G-banded metaphases derived from unstimulated bone marrow culture. Results were recorded according to the International System for Human Cytogenetic Nomenclature (ISCN-2020). Data analyzed using SPSS, version 24.0. Results: C1As were observed in 60/450 (13.3%) cases of B-ALL. Among C1As, 29 (48%) cases had t(1;19). There were 13 (45%) balanced and 16 (55%) unbalanced translocations. The aberrations without t(1;19) were seen in 31 (52%) cases including 1q duplication with hyperdiploidy in 14 (45%) cases. The median age for C1As with and without t(1;19) was eight years and six years while the median leukocyte count was 32 x 109/L vs. 17 x 109/L. Event-free survival (EFS) for cases with and without t(1;19) was 69% and 74.2% respectively. Conclusion: Despite the fact that the t(1;19) positive group had a higher median age, a higher white cell count and more CNS positives, the difference in EFS is statistically insignificant when compared to the t(1;19) negative cases. Furthermore, we found a survival difference between balanced and unbalanced t(1;19) groups, which is statistically insignificant but warrants large-scale prospective studies for further understanding.

Richter transformation in Chronic Lymphocytic Leukemia.

Chronic lymphocytic leukemia can evolve to an aggressive lymphoma-in most of the cases diffuse large B cells lymphoma, rarely Hodgkin lymphoma-and this complication is defined Richter syndrome (RS). Immunogenotypic features that characterize RS include unmutated IgHV status with high prevalence of IgHV4-39/D6-13/J5 sequence; deletion of chromosome 17p or 11q; activation of oncogenes as NOTCH1 and c-MYC; inactivation of onco-suppressors as TP53 and CDKN2A; high expression of CD38 in lymph-nodes. The prognosis of this condition is very poor: patients experience a rapid clinical deterioration with frequent therapeutic failure since the current options include suboptimal strategies as standard chemo-immunotherapy followed by hematopoietic stem cells transplantation or enrollment in clinical trials which investigate the efficacy of target drugs. Understanding the biology of such a heterogeneous condition is crucial to personalize the treatment and improve patient's survival.

Uncombable hair syndrome due to maternal uniparental disomy of chromosome 1.

Uncombable hair syndrome is a hair shaft condition in which the hair is frizzy, light in color (silver to light brown), and cannot be combed flat. Autosomal dominant (with complete or incomplete penetrance), autosomal recessive, and sporadic cases have been reported. In 2016 causative mutations in three genes were identified for uncombable hair syndrome, all with an autosomal recessive inheritance pattern: PADI3, TGM3, and TCHH. In many cases, however, there is still no molecular diagnosis. Here, we describe a case of autosomal recessive uncombable hair syndrome resulting from maternal uniparental disomy of chromosome 1.

Acrylonitrile's genotoxicity profile: mutagenicity in search of an underlying molecular mechanism.

Acrylonitrile (ACN) is a known rodent and possible human carcinogen. There have also been concerns as to it causing adverse reproductive health effects. Numerous genotoxicity studies at the somatic level in a variety of test systems have demonstrated ACN's mutagenicity; its potential to induce mutations in germ cells has also been evaluated. ACN is metabolized to reactive intermediates capable of forming adducts with macromolecules including DNA, a necessary first step in establishing a direct mutagenic mode of action (MOA) for its carcinogenicity. The mutagenicity of ACN has been well demonstrated, however, numerous studies have found no evidence for the capacity of ACN to induce direct DNA lesions that initiate the mutagenic process. Although ACN and its oxidative metabolite (2-cyanoethylene oxide or CNEO) have been shown to bind in vitro with isolated DNA and associated proteins, usually under non-physiological conditions, studies in mammalian cells or in vivo have provided little specification as to an ACN-DNA reaction. Only one early study in rats has shown an ACN/CNEO DNA adduct in liver, a non-target tissue for its carcinogenicity in the rat. By contrast, numerous studies have shown that ACN can act indirectly to induce at least one DNA adduct by forming reactive oxygen species (ROS) in vivo, but it has not been definitively shown that the resulting DNA damage is causative for the induction of mutations. Genotoxicity studies for ACN in somatic and germinal cells are summarized and critically reviewed. Significant data gaps have been identified for bringing together the massive data base that provides the basis of ACN's current genotoxicity profile.

Genotoxicity, DNA damage and sperm defects induced by vinblastine.

BACKGROUND: The treatment with chemotherapy may develop secondary tumors as a result of chemo genotoxicity. Sperm defects is another complication associated with chemo treatment. In this study the genotoxicity of vinblastine (VB) was estimated in both somatic and germ cells. MATERIALS: 85 mice were taken. Four single doses of VB at 3, 4.5, 6 and 10 mg/kg and three successive doses at 3, 4.5 and 6 mg/kg were taken for estimation of chromosomal aberrations (CAs). Four single doses of VB were involved in estimating the DNA fragmentation, and comet assay. For sperm abnormalities mice were injected with three successive doses of VB at 3, 4.5, and 6 mg/kg. RESULTS: The results demonstrated a significant frequency of DNA fragmentation in spleen cells and in the percentage of CAs in bone marrow. Numerical and structural aberrations were recorded with a pronounced number of polyploidy metaphases which reached (11.60%) after treatment with 6 mg/kg for three successive days vs zero for control. VB also induced a significant percentage of CAs in spermatocytes in the form of univalent. Sperm defects in the form of coiled tail, absence of acrosome and shapeless head and a significant DNA damage in the testes were recorded. The frequency of sperm abnormalities reached 11.06 ± 0.14 after treatment with highest tested dose (6 mg/kg) vs 3.04 ± 0.19 for control. CONCLUSION: VB is genotoxic in somatic and germ cells. Sperm defects induced by VB are of serious concern to future generations and may affect the fertility of cancer survivors.

Optical genome mapping for detection of chromosomal aberrations in prenatal diagnosis.

INTRODUCTION: Chromosomal aberrations are the most important etiological factors for birth defects. Optical genome mapping is a novel cytogenetic tool for detecting a broad range of chromosomal aberrations in a single assay, but relevant clinical feasibility studies of optical genome mapping in prenatal diagnosis are limited. MATERIAL AND METHODS: We retrospectively performed optical genome mapping analysis of amniotic fluid samples from 34 fetuses with various clinical indications and chromosomal aberrations detected through standard-of-care technologies, including karyotyping, fluorescence in situ hybridization, and/or chromosomal microarray analysis. RESULTS: In total, we analyzed 46 chromosomal aberrations from 34 amniotic fluid samples, including 5 aneuploidies, 10 large copy number variations, 27 microdeletions/microduplications, 2 translocations, 1 isochromosome, and 1 region of homozygosity. Overall, 45 chromosomal aberrations could be confirmed by our customized analysis strategy. Optical genome mapping reached 97.8% concordant clinical diagnosis with standard-of-care methods for all chromosomal aberrations in a blinded fashion. Compared with the widely used chromosomal microarray analysis, optical genome mapping additionally determined the relative orientation and position of repetitive segments for seven cases with duplications or triplications. The additional information provided by optical genome mapping will be conducive to characterizing complex chromosomal rearrangements and allowing us to propose mechanisms to explain rearrangements and predict the genetic recurrence risk. CONCLUSIONS: Our study highlights that optical genome mapping can provide comprehensive and accurate information on chromosomal aberrations in a single test, suggesting that optical genome mapping has the potential to become a promising cytogenetic tool for prenatal diagnosis.

A decade of change - lessons learned from prenatal diagnostics in Central Denmark region in 2008-2018.

INTRODUCTION: In 2011, it was decided to implement chromosomal microarray in prenatal testing in the Central Denmark Region, mainly due to the expected higher diagnostic yield. Chromosomal microarray was introduced gradually for an increasing number of pregnancies and without a transition period where both karyotyping and chromosomal microarray were performed: first malformations (2011), then large nuchal translucency (2013), then high risk at combined first trimester risk screening (2016) and finally for all indications (2018). This retrospective study summarizes 11 years of using chromosomal microarray in invasive prenatal testing and presents the effect on diagnostic yield and turnaround time. Furthermore, the concerns when introducing chromosomal microarray are presented and discussed. MATERIAL AND METHODS: Registry data from the Danish Fetal Medicine Database, the regional fetal medicine database, the Danish Cytogenetic Central Register and the local laboratory database at Department of Clinical Genetics were all combined, and a cohort of 147 158 singleton pregnancies with at least one ultrasound examination was established RESULTS: Of the 147 158 pregnancies, invasive sampling was performed (chorionic villi or amniocytes) in 8456, corresponding to an overall invasive rate of 5.8%. Between 2016 and 2018, 3.4% (95% confidence interval [CI] 2.8-4.2%; n = 86) of the invasive samples (n = 2533) had a disease causing copy number variant and 5.3% (95% CI 4.4-6.2%; n = 133) had trisomies and other aneuploidies. The turnaround time more than halved from 14 days to an average of 5.5 days for chorionic villus sampling. CONCLUSIONS: Chromosomal microarray identified 5.3% trisomies and 3.4% copy number variants, thereby increased the diagnostic yield by more than 64% compared with karyotype only and it also more than halved the turnaround time. Some preliminary concerns proved real, eg prenatal counseling complexity, but these have been resolved over time in a clinical path with expert consultations.

Germination, cytotoxicity, and mutagenicity in Lactuca sativa L. and Passiflora alata Curtis in response to sewage sludge application.

The physical and chemical characteristics of the soil can influence plant growth. When sewage sludge (SS) is applied as a soil fertilizer, the accumulation of non-essential elements contained in it can be toxic for plants. The aim of this study was to understand the effect of SS dosage on the cell cycle of Lactuca sativa L. meristematic cells and on the initial growth of L. sativa and Passiflora alata Curtis. Nine concentrations of SS + distilled water (mg dm-3) corresponding to 0, 20, 40, 60, 80, 120, 160, 320, and 520 t ha-1 were tested in four replicates of 25 seeds. Chemical analysis showed an increase in pH of the sludge from 0 to 80 t ha-1 SS followed by its stabilization thereafter. The highest electrical conductivity was observed at 520 t ha-1 SS. SS negatively affected the germination and initial growth of seedlings from P. alata and L. sativa. Cytogenetic analysis on 6000 L. sativa meristematic cells for each treatment revealed that SS could adversely affect the genetic stability of this species. SS concentrations above 120 t ha-1 adversely affected the germination and early seedling growth of L. sativa and P. alata. At high concentrations (120 t ha-1), SS induced genetic lesions in L. sativa, along with chromosomal and nuclear alterations.

Cytogenetic damage by vanadium(IV) and vanadium(III) on the bone marrow of mice.

Vanadium is a strategic metal that has many important industrial applications and is generated by the use of burning fossil fuels, which inevitably leads to their release into the environment, mainly in the form of oxides. The wastes generated by their use represent a major health hazard. Furthermore, it has attracted attention because several genotoxicity studies have shown that some vanadium compounds can affect DNA; among the most studied compounds is vanadium pentoxide, but studies in vivo with oxidation states IV and III are scarce and controversial. In this study, the genotoxic and cytotoxic potential of vanadium oxides was investigated in mouse bone marrow cells using structural chromosomal aberration (SCA) and mitotic index (MI) test systems. Three groups were administered vanadium(IV) tetraoxide (V2O4) intraperitoneally at 4.7, 9.4 or 18.8 mg/kg, and three groups were administered vanadium(III) trioxide (V2O3) at 4.22, 8.46 or 16.93 mg/kg body weight. The control group was treated with sterile water, and the positive control group was treated with cadmium(II) chloride (CdCl2). After 24 h, all doses of vanadium compounds increased the percentage of cells with SCA and decreased the MI. Our results demonstrated that under the present experimental conditions and doses, treatment with V2O4 and V2O3 induces chromosomal aberrations and alters cell division in the bone marrow of mice.

Genotoxicity of nedaplatin in cultured lymphocytes: modulation by vitamin E.

Nedaplatin is a chemotherapeutic agent used widely in cancer therapy. Nedaplatin has been shown to cause DNA damage to cells via the induction of oxidative stress. Vitamin E (Vit E) has an anti-mutagenic activity that can protect cells from DNA damaging agents. The objective of this study is to examine the genotoxic and cytotoxic effects of nedaplatin in human cultured lymphocytes. In addition, modulation of such effects by Vit E was also examined. The frequencies of sister chromatid exchange (SCE) and chromosomal aberrations (CAs) were used as an indicator for genotoxicity. The mitotic and proliferative indices were used to examine the cytotoxic effects of nedaplatin. The results showed that nedaplatin significantly elevated SCE and CA frequencies in human lymphocytes (p Ë‚ 0.01). The increases in the frequencies of SCE and CA caused by nedaplatin were lowered by pretreatment treatment with Vit E (p < 0.05). Nedaplatin significantly lowered mitotic index but Vit E pretreatment did not modulate this effect. These results suggest that Vit E has the potential to ameliorate the genotoxicity of nedaplatin in cultured lymphocytes.

Hematological, biochemical, genotoxic, and histopathological changes induced by pyridaben.

The current work examined the genotoxic effects of pyridaben (PDB) in male Sprague Dawley rats. Twenty Sprague Dawley rats were divided into four equal groups; the first group was used as a control group; the other three groups were exposed to 19, 28.5, and 57 mg/kg b.w PDB by oral gavage for 4 weeks. Blood samples were collected for hematological and biochemical parameters; femoral bone marrow was flushed for chromosomal aberrations (CA) assay and liver samples were used for the analysis of gene expression of IL-6 and Casp-3 as well as histopathological and immunhistochemical investigation for Casp-3. The results showed that PDB exposure lead to non-significant changes in hematological parameters in all PDB administrated groups while malondialdehyde, glutathione peroxidase, aspartate aminotransferase, and alkaline phosphatase were significantly increased in 19 and 57 mg/kg PDB doses groups Also, gene expression of IL-6 and Casp-3 revealed a significant increase in 28.5 and 57 mg/kg PDB doses groups as compared with the control. However, there was no significant change in the percentage of CAs in bone marrow cells in all PDB-exposed groups. The histopathological and immunhistochemical examination showed focal areas of inflammatory cellular infiltration with fibrosis in 57 mg/kg b.w PDB dose group accompanied by the severe positive reaction of caspase3 in the liver.

Cytotoxicity and genotoxicity evaluation of chloroform using Vicia faba roots.

Chloroform is a widely used industrial chemical that can also pollute the environment. The aims of this study were to examine the potential cytotoxicity and genotoxicity of chloroform on plant cells, using the Vicia faba bioassay. Chloroform was evaluated at concentrations of 0.1, 0.5, 1, 2, and 5 mg·L-1. The following parameters were analyzed: the mitotic index (MI), micronucleus (MN) frequency, chromosomal aberration (CA) frequency, and malondialdehyde (MDA) content. The results showed that exposure to increasing concentrations of chloroform caused a decrease in MI and an increase in the frequency of MN in Vicia faba root tip cells, relative to their controls. Moreover, various types of CA, including C-mitosis, fragments, bridges, laggard chromosomes, and multipolar mitosis, were observed in the treated cells. The frequency of MN was positively correlated with the frequency of CA in exposure to 0.1-1 mg·L-1 chloroform. Furthermore, chloroform exposure induced membrane lipid peroxidation damage in the Vicia faba radicle, and a linear correlation was observed between the MDA content and the frequency of MN or CA. These findings indicated that chloroform exposure can result in oxidative stress, cytotoxicity, and genotoxicity in plant cells.

Use of the Allium cepa Model to Assess the Cytogenotoxicity of Luffariella herdmani Marine Sponge Extract.

Marine sponge extracts are known to contain potentially toxic compounds that have biological activities of possible pharmacological interest. Thus, it is vital that biological models are used for the preliminary toxicity screening of such extracts. The present study reports the use of Allium cepa, a low-cost plant-based in vivo model, to assess the cytotoxicity and genotoxicity of Luffariella herdmani marine sponge crude extract (SCE). Pre-germinated onion bulbs, exposed for 96 hours to different concentrations of SCE (ranging from 0.3125 to 20 µg/ml), were used to determine general cytotoxicity. Root length as well as morphological abnormalities were recorded. Genotoxicity was assessed by exposing the root tips to SCE (0.3125-20 µg/ml) and the appropriate controls for 48 hours, and then staining with acetocarmine. The Mitotic Index (MI), Mitotic Phase Indices (MPIs) and chromosomal aberrations were evaluated and recorded. SCE inhibited A. cepa root growth (EC50 = 10.34 µg/ml) and elicited a mitodepressive effect (LC50 = 1.95 µg/ml) in a dose-dependent and significant manner. In addition, macroscopic alterations as well as chromosomal aberrations were detected. Overall, our findings indicate that L. herdmani crude extract exhibits cytotoxic and genotoxic activity, suggesting that it might contain substances with anti-proliferative/anticancer potential that could be subject to further characterisation.