Evaluation of potential role of R-loop and G-quadruplex DNA in the fragility of c-MYC during chromosomal translocation associated with Burkitt's lymphoma.

t(8;14) translocation is the hallmark of Burkitt's lymphoma and results in c-MYC deregulation. During the translocation, c-MYC gene on chromosome 8 gets juxtaposed to the Ig switch regions on chromosome 14. Although the promoter of c-MYC has been investigated for its mechanism of fragility, little is known about other c-MYC breakpoint regions. We have analyzed the translocation break points at the exon 1/intron 1 of c-MYC locus from patients with Burkitt's lymphoma. Results showed that the breakpoint region, when present on a plasmid, could fold into an R-loop confirmation in a transcription-dependent manner. Sodium bisulfite modification assay revealed significant single-strandedness on chromosomal DNA of Burkitt's lymphoma cell line, Raji, and normal lymphocytes, revealing distinct R-loops covering up to 100 bp region. Besides, ChIP-DRIP analysis reveals that the R-loop antibody can bind to the breakpoint region. Further, we show the formation of stable parallel intramolecular G-quadruplex on non-template strand of the genome. Finally, incubation of purified AID in vitro or overexpression of AID within the cells led to enhanced mutation frequency at the c-MYC breakpoint region. Interestingly, anti-γH2AX can bind to DSBs generated at the c-MYC breakpoint region within the cells. The formation of R-loop and G-quadruplex was found to be mutually exclusive. Therefore, our results suggest that AID can bind to the single-stranded region of the R-loop and G4 DNA, leading to the deamination of cytosines to uracil and induction of DNA breaks in one of the DNA strands, leading to double-strand break, which could culminate in t(8;14) chromosomal translocation.

Optical genome mapping enables constitutional chromosomal aberration detection.

Chromosomal aberrations including structural variations (SVs) are a major cause of human genetic diseases. Their detection in clinical routine still relies on standard cytogenetics. Drawbacks of these tests are a very low resolution (karyotyping) and the inability to detect balanced SVs or indicate the genomic localization and orientation of duplicated segments or insertions (copy number variant [CNV] microarrays). Here, we investigated the ability of optical genome mapping (OGM) to detect known constitutional chromosomal aberrations. Ultra-high-molecular-weight DNA was isolated from 85 blood or cultured cells and processed via OGM. A de novo genome assembly was performed followed by structural variant and CNV calling and annotation, and results were compared to known aberrations from standard-of-care tests (karyotype, FISH, and/or CNV microarray). In total, we analyzed 99 chromosomal aberrations, including seven aneuploidies, 19 deletions, 20 duplications, 34 translocations, six inversions, two insertions, six isochromosomes, one ring chromosome, and four complex rearrangements. Several of these variants encompass complex regions of the human genome involved in repeat-mediated microdeletion/microduplication syndromes. High-resolution OGM reached 100% concordance compared to standard assays for all aberrations with non-centromeric breakpoints. This proof-of-principle study demonstrates the ability of OGM to detect nearly all types of chromosomal aberrations. We also suggest suited filtering strategies to prioritize clinically relevant aberrations and discuss future improvements. These results highlight the potential for OGM to provide a cost-effective and easy-to-use alternative that would allow comprehensive detection of chromosomal aberrations and structural variants, which could give rise to an era of "next-generation cytogenetics."

Atypicality index as an add-on to combined first-trimester screening for chromosomal aberrations.

OBJECTIVES: To compute a set of atypicality indices based on combined first-trimester screening (cFTS) markers and second-trimester estimated fetal weight (EFW), and to demonstrate their potential in identifying pregnancies at reduced or increased risk of chromosomal aberrations following a low-risk cFTS result. METHODS: The atypicality index quantifies the unusualness of an individual set of measurements relative to a reference distribution and can be computed from any variables or measurements available. A score of 0% on the atypicality index represents the most typical profiles, while a score of 100% indicates the highest level of atypicality. From the Danish Fetal Medicine Database, we retrieved data on all pregnant women seen for cFTS in the Central Denmark Region between January 2008 and December 2018. All pregnancies with a cytogenetic or molecular analysis obtained prenatally, postnatally or following pregnancy loss or termination were identified. A first-trimester atypicality index (AcFTS) was computed based on nuchal translucency (NT) thickness, maternal serum free ß-human chorionic gonadotropin (ß-hCG) and pregnancy-associated plasma protein-A (PAPP-A). Furthermore, a second-trimester index (AcFTS + EFW) was computed from cFTS markers and EFW from a routine second-trimester anomaly scan. All pregnancies were stratified into subgroups based on their atypicality levels and their cFTS risk estimates. The risk of chromosomal aberrations in each subgroup was then compared with the overall prevalence, and a graphical presentation of the multivariate measurement profiles was developed. RESULTS: We retrieved data on 145 955 singleton pregnancies, of which 9824 (6.7%) were genetically examined. Overall, 1 in 122 (0.82% (95% CI, 0.77-0.87%)) of all pregnancies seen for cFTS were affected by a fetal chromosomal aberration, and in screen-negative pregnancies (cFTS trisomy 21 risk < 1 in 100 and/or trisomy 18/13 risk < 1 in 50), 0.41% (95% CI, 0.38-0.44%) were affected. In screen-negative pregnancies with a typical first-trimester profile (AcFTS < 80%), the risk of chromosomal aberrations was significantly reduced (0.28%) compared with the overall risk. The risk of chromosomal aberrations increased with higher atypicality index to 0.49% (AcFTS [80-90%)), 1.52% (AcFTS [90-99%)) and 4.44% (AcFTS ≥ 99%) and was significantly increased in the two most atypical subgroups. The same applied for the second-trimester atypicality index, with risks of chromosomal aberrations of 0.76% and 4.16% in the two most atypical subgroups (AcFTS + EFW [90-99%) and AcFTS + EFW ≥ 99%, respectively). CONCLUSIONS: As an add-on to cFTS, the atypicality index identifies women with typical measurement profiles, which may provide reassurance, whereas atypical profiles may warrant specialist referral and further investigation. In pregnancies identified as low risk on cFTS but with a highly atypical distribution of NT, PAPP-A and ß-hCG, the risk of a chromosomal aberration is substantially increased. The atypicality index optimizes the interpretation of pre-existing prenatal screening profiles and is not limited to cFTS markers or EFW. © 2023 International Society of Ultrasound in Obstetrics and Gynecology.

Lanthanum nitrate demonstrated no genotoxicity in the conducted tests.

Given the widespread applications in industrial and agricultural production, the health effects of rare earth elements (REEs) have garnered public attention, and the genotoxicity of REEs remains unclear. In this study, we evaluated the genetic effects of lanthanum nitrate, a typical representative of REEs, with guideline-compliant in vivo and in vitro methods. Genotoxicity assays, including the Ames test, comet assay, mice bone marrow erythrocyte micronucleus test, spermatogonial chromosomal aberration test, and sperm malformation assay were conducted to assess mutagenicity, chromosomal damage, DNA damage, and sperm malformation. In the Ames test, no statistically significant increase in bacterial reverse mutation frequencies was found as compared with the negative control. Mice exposed to lanthanum nitrate did not exhibit a statistically significant increase in bone marrow erythrocyte micronucleus frequencies, spermatogonial chromosomal aberration frequencies, or sperm malformation frequencies compared to the negative control (P > 0.05). Additionally, after a 24-h treatment with lanthanum nitrate at concentrations of 1.25, 5, and 20 µg/ml, no cytotoxicity was observed in CHL cells. Furthermore, the comet assay results indicate no significant DNA damage was observed even after exposure to high doses of lanthanum nitrate (20 µg/ml). In conclusion, our findings suggest that lanthanum nitrate does not exhibit genotoxicity.

Genotoxicity evaluation of food additive titanium dioxide using a battery of standard in vivo tests.

The increasing use of titanium dioxide (TiO2) nanoparticles (NPs) has raised concern about the safety of food additive TiO2. TiO2 has been considered no longer safe by EFSA due to concerns over genotoxicity, however, there are conflicting opinions upon the safety of TiO2 as a food additive, and the number of in vivo genotoxicity studies conducted on food additive TiO2 was limited. In order to investigate the potential genotoxicity of food additive TiO2, we evaluated the genotoxicity of a commercial food additive TiO2 (average size of 135.54 ± 41.01 nm, range from 60.83 to 230.16 nm, NPs account for 30% by number) using a battery of standard in vivo tests, including mammalian erythrocyte micronucleus test, mammalian bone marrow chromosomal aberration test and in vivo mammalian alkaline comet test. After 15 days of consecutive intragastric administration at doses of 250, 500, and 1000 mg/kgBW, food additive TiO2 neither increased the frequencies of bone marrow micronuclei or chromosomal aberration in mice, nor induced DNA strand breakage in rat liver cells. These results indicate that under the condition of this study, food additive TiO2 does not have genotoxic potential although it contains a fraction of NPs.

In vitro genotoxicological evaluation of protein-rich powder derived from Xanthobacter sp. SoF1.

One way of limiting the environmental impact of food production and improving food security is to replace part of the animal- or plant-based protein in the human diet with protein sourced from microorganisms. The recently discovered bacterium Xanthobacter sp. SoF1 (VTT-E-193585) grows autotrophically using carbon dioxide gas as the only carbon source, yielding protein-rich biomass that can be processed further into a powder and incorporated into various food products. Since the safety of this microbial protein powder for human consumption had not been previously assessed, its genotoxic potential was evaluated employing three internationally recognized and standardized studies: a bacterial reverse mutation test, an in vitro chromosomal aberration assay in human lymphocytes, and an in vitro micronucleus test in human lymphocytes. No biologically relevant evidence of genotoxicity or mutagenicity was found.

Safety evaluation of Gamisoyo-san: genotoxicity, acute toxicity, and influence on drug-metabolizing enzymes.

Gamisoyo-san is an herbal formula widely used to treat psychological issues, menopausal symptoms, and dysmenorrhea. However, there is insufficient information on its safety profile. This study aimed to confirm the genotoxic and acute toxic potential of Gamisoyo-san. We performed a battery of tests, which included a bacterial reverse mutation test (Ames test) using five bacterial strains, an in vitro chromosomal aberration test using Chinese hamster lung (CHL) cells, an in vivo micronucleus test in mice, and human Cytochrome P450 (CYP450) and UDP-glucuronosyltransferase (UGT) assays. In the acute toxicity study, male and female rats were orally administered Gamisoyo-san 1000, 2000, or 5000 mg/kg and observed for 14 days. The activities of human CYP450s and UGTs were evaluated using recombinant baculosomes. Gamisoyo-san showed no signs of genotoxicity in the five bacterial strains, CHL cells, or mouse bone marrow cells. The acute toxicity test showed that the median lethal dose (LD50) of Gamisoyo-san was greater than 5000 mg/kg in rats. Gamisoyo-san inhibited the activities of CYP1A2, CYP2C19, and UGT1A1. In conclusion, Gamisoyo-san may not exert severe toxicological events or genotoxic effects at doses up to 5000 mg/kg in rats.

Repeated dose toxicity studies of Trichostatin A in Swiss albino mice through oral and intravenous route of administration with special emphasis on genotoxicity.

Intravenous and oral 14 d repeated dose toxicity studies of Trichostatin A (TSA) were carried out in Swiss albino mice using low, intermediate, and high doses. Intravenous doses were 10, 25, and 50 µg/kg b.w while the oral doses were 20, 50, and 100 µg/kg b.w. Respective control groups of mice were administered phosphate buffered saline (vehicle only) for 14 consecutive days. All external morphological, hematological, biochemical, urine, histopathological, food intake in addition to body weight and vital organ weight were recorded. During the study no mortality in any animal was observed in either treatment routes. There were no significant changes in morphology, food intake, hematology, biochemical, urine analysis, organ weight. Animals treated high dose of TSA intravenously (50 µg/kg b.w) and orally (100 µg/kg b.w) had enlarged, congested, and discolored kidneys which were statistically significant. Histopathological studies had shown statistically significant degenerated glomerulus in high dose of intravenous and orally treated animals and degenerated tubule were found in orally treated animals. Genotoxicity was evaluated using micronucleus frequency at 14 and 21 d after treatment and chromosomal aberration at 21 d after treatment. Micronucleaus assay and chromosomal assay however did not show any significant changes at any doses and administration routes. Therefore, this study concludes that dose ∼25 µg/kg and ∼50 µg/kg b.w may be considered as No Observed Adverse Effect Level (NOAEL) for intravenous and oral administration of TSA respectively.

Prevalence of chromosomal disorders in cases with congenital heart defect: registry-based study from Denmark between 2008 and 2018.

OBJECTIVE: To estimate the prevalence of chromosomal conditions in all fetuses and children with major congenital heart defect (CHD) in Denmark between 2008 and 2018. METHODS: This was a national registry-based study including all singleton pregnancies with a prenatally or postnatally diagnosed major CHD usually requiring surgery within the first year after birth and a due date between July 2008 and December 2018 in Denmark. Data were retrieved from the Danish Fetal Medicine Database (DFMD) and the Danish Cytogenetic Central Register (DCCR) in October 2020. The DCCR contains information on all prenatal and postnatal genetic analyses, including karyotyping, chromosomal microarray, polymerase chain reaction, multiplex ligation-dependent probe amplification and fluorescence in-situ hybridization. All cases were reviewed by a clinical geneticist, and genetic changes were classified as pathogenic, likely pathogenic, variant of uncertain significance, likely benign or benign. Pathogenic and likely pathogenic variants were considered to be abnormal. Cases with CHD without any registered chromosomal analysis reported were considered genetically normal. Isolated CHD was defined as a case with major CHD without any other structural malformations detected prenatally or postnatally. Results are given as n (%). Comparisons between isolated and non-isolated cases were performed using logistic regression analysis, and data are presented as odds ratios (ORs) with 95% CIs. RESULTS: A total of 8482 cases with any cardiovascular diagnosis were retrieved from the DFMD. Twins (n = 112) and minor CHD cases (n = 6921) were excluded, resulting in 1449 cases with major CHD. Of the included cases, 918 (63.4%) underwent chromosomal analysis. An abnormal test result was found in 187 cases, giving a prevalence of a chromosomal condition of 12.9% (95% CI, 11.2-14.7%) among all cases with major CHD. The highest prevalence of a chromosomal condition was found in cases with pulmonary atresia with intact ventricular septum and those with truncus arteriosus (both 28.6%), while the lowest prevalence was found in cases with transposition of the great arteries (2.2%) and congenitally corrected transposition of the great arteries (0%). In isolated cases of transposition of the great arteries, the prevalence of a chromosomal condition was 0.6%. The overall OR for a chromosomal condition in non-isolated cases compared with isolated cases was 2.72 (95% CI, 1.90-3.88). CONCLUSIONS: We found an overall prevalence of a chromosomal condition of 12.9% among cases with major CHD in a national cohort with a high participation rate in first- and second-trimester screening, without employing whole genome and whole exome sequencing. The prevalence of a chromosomal condition varied considerably according to CHD diagnosis and presence of associated extracardiac malformations. These findings are important for prenatal counseling. © 2022 The Authors. Ultrasound in Obstetrics & Gynecology published by John Wiley & Sons Ltd on behalf of International Society of Ultrasound in Obstetrics and Gynecology.

Genotoxic potential of different nano-silver halides in cultured human lymphocyte cells.

Most antibacterial applications in nanotechnology are carried out using silver nanoparticles (AgNPs). However, there is a dearth of information on the biological effects of AgNPs on human blood cells. In this study, the cytotoxic and genotoxic potentials of ionic silver (Ag+), AgNP, silver bromide (AgBr), silver chloride (AgCl), and silver iodide (AgI) were evaluated through chromosome aberration (CA) test and cytokinesis-blocked micronucleus (CBMN) test in human cultured lymphocytes in vitro. Furthermore, the potential damages that can cause to DNA were evaluated through alkaline single cell gel electrophoresis (Comet) assay on isolated lymphocytes. The results showed that AgNPs exerted cytotoxic effects by reducing the cytokinesis-block proliferation index and mitotic index at 24 and 48 h. AgNPs also increased micronucleus (MN) formation at both exposure times in the cultured cells. Meanwhile, AgCl had no genotoxic effects on the human lymphocyte cultured cells but had a cytotoxic effect at high doses. AgNP, Ag+, AgBr, and AgI caused substantial DNA damage by forming DNA strand breaks. They may also have clastogenic, genotoxic and cytotoxic effects on human lymphocyte cells. Based on the foregoing findings, silver nanomaterials may have genotoxic and cytotoxic potentials on human peripheral lymphocytes in vitro.

Elucidation of the cytogenotoxic potential of vigabatrin and its in silico computer-assisted DNA interaction.

Vigabatrin (VGB) is a gammaaminobutyric acid-ergic (GABA-ergic) antiepileptic drug (AED) and is one of 2 approved drugs available to treat infantile spasms (IS). The aim of this study is to elucidate conflicting data on the toxic effects of VGB and to obtain detailed information about its possible cytogenotoxic effects in human lymphocytes. For this purpose, in vitro Chromosomal Aberration (CA), Sister Chromatid Exchange (SCE), Micronucleus (MN) tests, and Comet Assay were performed to determine possible genotoxic and cytotoxic effects of VGB. In addition, the binding energy level of VGB to DNA was determined in silico by molecular docking. The highest concentration (80 µg/ml) of VGB increased the SCE, CA, MN and micronucleated binuclear cell (BNMN) frequency significantly compared to the control after 24 and 48 hours of treatment. In the tail density and tail length parameters, the dose-dependent increase was found to be statistically significant compared to the control. At the 40 and 80 µg/ml concentrations of VGB for 48 hours caused a statistically significant increase in both CA/Cell and AC percentages, while MI and NDI decreased only significantly at the highest concentration (80 µg/ml) causing. In the Comet Assay head density, tail density and tail length parameters, the dose-dependent increase was found to be statistically significant compared to the control. Also, the in silico molecular docking analysis showed that VGB interacts with B-DNA close to the threshold binding energy. The lowest negative free binding energy (ΔG binding) was found as -5.13 kcal/mol. In conclusion, all results are evaluated together, it has been determined that VGB has cytogenotoxic effects in vitro and binds to DNA in silico with significant free binding energy.

Genotoxic and mutagenic potential of 7-methylxanthine: an investigational drug molecule for the treatment of myopia.

7-Methylxanthine (7-MX, CAS No. 552-62-5, purity 99.46%) is the first orally administered drug candidate, which showed anti-myopic activity in different pre-clinical studies. In the present study, we investigated the in-vivo genotoxic and mutagenic toxicity of 7-MX in Wistar rats using comet/single-cell gel electrophoresis, chromosomal aberration and micronucleus assays after oral administration. For the single-dose study (72 h), two doses of 7-MX 300 and 2000 mg/kg body weight were selected. For a repeated dose 28 d study, three doses (250, 500, and 1000 mg/kg) of 7-MX were selected. The doses were administered via oral gavage in the suspension form. Blood and major vital organs such as bone marrow, lung and liver were used to perform comet/single cell gel electrophoresis, chromosomal aberration, and micronucleus assays. The in-vitro Ames test was performed on TA98 and TA100 strains. In the chromosomal aberration study, a non-significant increase in deformities such as stickiness, ring chromosome, and endoreduplication was observed in bone marrow cells of 7-MX treated groups. These chromosomal alterations were observed upon treatment with doses of 2000 mg/kg single dose for 72 h and 1000 mg/kg repeated dose for 28 d. At a dose of 500 mg/kg, DNA damage in terms of tail length, tail moment, % tail DNA and the olive tail moment was also found to be non-significant in 7-MX treated groups. The Ames test showed the non-mutagenic nature of 7-MX in both strains of TA98 and TA100 of Salmonella typhimurium with or without metabolic activation. Thus, the present work is interesting in view of the non- genotoxicity and non-mutagenicity of repeated doses of 7-MX.

Mitotic chromosomal abnormalities and DNA polymorphism in the Nile tilapia (Oreochromis niloticus, Linnaeus, 1758) as a biomarker for water pollution by heavy metals.

Mitotic chromosomal aberrations and DNA polymorphism (RAPD marker) were carried out on the Nile tilapia Oreochromis niloticus collected from five sites in Minia governorate, Egypt to test their applicability as biomonitors for heavy metal contaminants of water. The diploid chromosome number of O. niloticus population was 2 n = 44. Different types of chromosomal aberrations were recorded (e.g., deletion, ring, centromeric attenuation, end-to-end association, dicentric chromosome, stickiness chromosomes, endomitosis, fragments and chromatid gap). The chromosomal aberrations varied between O. niloticus population collected from five sites, and the most common type was ring (R) chromosomes. Samples obtained from Bahr Yousef and Irrigation drain exhibited the highest aberration frequency. The frequency of chromosomal aberration was positively correlated with the concentration of heavy metals where their concentration in the surface water of Irrigation drain and Bahr Yousef exceeded the limits defined by WHO as well as the concentration of Pb in muscles. The RAPD marker was also used to identify genetic variation among Nile tilapia samples collected from five different water sources. It created polymorphic and unique bands that can be used as genetic markers to track DNA variations. The dendrogram also revealed that exposure to heavy metal pollution causes gradual accumulation of variance, whereas areas subjected to environmental stress showed higher genetic variation and clustered together.

Evaluation of the probable synergistic toxicity of selected potentiated antiretroviral and antibiotics on some aquatic biomarker organisms.

Environmental effects of active pharmaceutical compounds (APCs) in the environment are not well characterized, hence the need for comprehensive evaluation. This study employed three bioassays using three organisms, namely, Allium cepa, Daphnia magna, and Salmonella typhimurium, in the ecotoxicity study of lone and a mixture of selected APCs, namely, lamivudine (L), an antiretroviral, and ciprofloxacin (C) and sulfamethoxazole (S), antibiotics, at a concentration range between 10 and 100 ppb, in order to evaluate the potential of the lone and ternary mixture to exert synergistic toxicity. Study results from exposure to lone APCs showed that the L, C, and S trio individually had fatal impacts on daphnids, with mortality rates of 100, 75, and 95%, respectively, after 48 h. Sulfamethoxazole showed a mutagenic tendency, with a mutation ratio (background/sample ratio) of 2.0. Lamivudine showed a lethal impact on the root length of A. cepa (p > 0.05, p = 3.60E-3). Further microscopic examination of the A. cepa root tip revealed chromosomal aberrations on exposure to each compound. The LCS-mix ecotoxicology bioassays indicated a synergistic effect on the daphnids, probably due to potentiation. Although the LCS mix had a cytotoxic effect (evidenced by the absence of bacteria colonies) on exposed TA 98 P450 Salmonella typhimurium strain, this effect was not observed in other bacterial strains. Microscopic examination of A. cepa exposed to the LCS-mix revealed an aberration in the mitotic stage of the cell. The impact of combination of the pharmaceuticals in aqueous ecosystems was greater than when exposed to the tested individual pharmaceutical compounds. Study result showed that these compounds have tendencies to pose a higher risk to exposed living entities when in combined/potentiated forms, and this could lead to distortion of the regular functioning of the ecosystem, particularly bacterial and other microbial populations that are listed among primary producers of the aquatic food web.

High-resolution genetic linkage map and height-related QTLs in an oil palm (Elaeis guineensis) family planted across multiple sites.

A refined SNP array containing 92,459 probes was developed and applied for chromosome scanning, construction of a high-density genetic linkage map and QTL analysis in a selfed Nigerian oil palm family (T128). Genotyping of the T128 mapping family generated 76,447 good quality SNPs for detailed scanning of aberration and homozygosity in the individual pseudo-chromosomes. Of them, 25,364 polymorphic SNPs were used for linkage analysis resulting in an 84.4% mapping rate. A total of 21,413 SNPs were mapped into 16 linkage groups (LGs), covering a total map length of 1364.5 cM. This genetic map is 16X denser than the previous version used to establish pseudo-chromosomes of the oil palm reference genome published in 2013. The QTLs associated with height, height increment and rachis length were identified in LGs TT05, 06, 08, 15 and 16. The present QTLs as well as those published previously were tagged to the reference genome to determine their chromosomal locations. Almost all the QTLs identified in this study were either close to or co-located with those reported in other populations. Determining the QTL position on chromosomes was also helpful in mining for the underlying candidate genes. In total, 55 putative genes and transcription factors involved in the biosynthesis, conjugation and signalling of the major phytohormones, especially for gibberellins and cell wall morphogenesis were found to be present in the identified genomic QTL regions, and their potential roles in plant dwarfism are discussed. Supplementary Information: The online version contains supplementary material available at 10.1007/s12298-023-01360-2.

Evaluation of the cytotoxic, anticancer, and genotoxic activities of Acacia nilotica flowers and their effects on N-methyl-N-nitrosourea-induced genotoxicity in mice.

PURPOSE: In this study, two main research objectives were examined: (1) the cytotoxic and anticancer activities of the aqueous methanol extract from Acacia nilotica flowers on three human cancer cells, namely lung A549, breast MCF-7, and leukemia THP-1 cells, and (2) the genotoxic effects of A. nilotica extract and its influence on DNA damage induced by N-methyl-N-nitrosourea (MNU) in mice. METHODS: Mice were orally treated with A. nilotica extract (200, 500, and 800 mg/kg for 4 days) with or without MNU (80 mg/kg intraperitoneally for 24 h). RESULTS: In vitro experiments showed that A549 cells were the most sensitive to A. nilotica extract among the tested cell lines. A. nilotica extract inhibited A549 cell proliferation by blocking the cell cycle at the G2/M phase and accumulating apoptotic cells in the sub-G0/G1 phase in A549 cells. In vivo experiments showed that MNU induced positive and negative genotoxicity in bone marrow cells and spermatocytes, respectively. Negative genotoxicity was observed in A. nilotica extract-treated groups only. However, A. nilotica extract (800 mg/kg) remarkably increased comet tail formation in bone marrow cells. Unexpectedly, the absence of antigenotoxicity was observed in three cotreated groups with A. nilotica extract and MNU compared with the MNU-treated group. Astonishingly, cotreatment with MNU and A. nilotica extract at a dose above 200 mg/kg remarkably increased micronucleus and comet tail formation in bone marrow cells compared with the MNU-treated group. CONCLUSIONS: A. nilotica extract possessed anticancer activity with relative genotoxic effects at high doses.

Toxicological assessment of enzyme-treated Zizania latifolia extract: Oral toxicology and genotoxicity in rats.

Zizania latifolia Turcz. has long been used as a food source in Southeast Asia. The grains, stems, and leaves of Z. latifolia and its major component, tricin, have also been studied to determine their biological activities. Previously, we hydrolyzed the aerial part of Z. latifolia using an enzyme mixture to maximize the tricin content of the Z. latifolia extract. However, the safety of enzyme-treated Z. latifolia extract (ETZL; DermaNiA™) has not yet been determined. In this study, we performed an in vivo 90-day repeated-dose evaluation and genotoxicity study to assess the toxicological potential of ETZL. EZTL did not exhibit genotoxicity in the bacterial reverse mutation test, in vitro chromosomal aberration assay, or in vivo micronucleus test. Moreover, no changes in body weight or hematological and serum biological parameters were observed in male or female rats under high-dose EZTL treatment (5000 mg/kg body weight (bw)/day) for 90 days with a 4-week recovery period. Significant changes were noted in the forestomach, kidneys, and adrenal glands in the test groups, but these changes, or tendency for recovery, were not observed in the recovery group. Based on these data, the no adverse effect level was determined to be 1250 mg/kg bw/day in rats.

Audit of the first > 7500 noninvasive prenatal aneuploidy tests in a Swiss genetics center.

OBJECTIVES: Noninvasive prenatal testing (NIPT) is actually the most accurate method of screening for fetal chromosomal aberration (FCA). We used pregnancy outcome record to evaluate a complete data set of single nucleotide polymorphism-based test results performed by a Swiss genetics center. MATERIALS AND METHODS: The Panorama® test assesses the risk of fetal trisomies (21, 18 and 13), gonosomal aneuploidy (GAN), triploidy or vanishing twins (VTT) and five different microdeletions (MD). We evaluated all 7549 test results meeting legal and quality requirements taken in women with nondonor singleton pregnancies between April 2013 and September 2016 classifying them as high or low risk. Follow-up ended after 9 months, data collection 7 months later. RESULTS: The Panorama® test provided conclusive results in 96.1% of cases, detecting 153 FCA: T21 n = 76, T18 n = 19, T13 n = 15, GAN n = 19, VTT n = 13 and MD n = 11 (overall prevalence 2.0%). Pregnancy outcome record was available for 68.6% of conclusive laboratory results, including 2.0% high-risk cases. In this cohort the Panorama® test exhibited 99.90% sensitivity for each trisomy; specificity was 99.90% for T21, 99.98% for T18 and 99.94% for T13. False positive rate was 0.10% for T21, 0.02% for T18 and 0.06% for T13. CONCLUSION: SNP-based testing by a Swiss genetics center confirms the expected accuracy of NIPT in FCA detection.

Cytogenetic effects of antidiabetic drug metformin.

Metformin (MET) is the first-choice antidiabetic drug for type 2 diabetes mellitus treatment. In this study, the genotoxic potential of MET was evaluated by using chromosome aberrations (CAs), sister chromatid exchanges (SCEs), and micronucleus (MN) assays in human peripheral lymphocytes as well as comet assay in isolated lymphocytes. Human lymphocytes were treated with different concentrations of MET (12.5, 25, 50, 75, 100, and 125 µg/mL) for 24 h and 48 h. A negative and a positive control (Mitomycin-C-MMC, 0.20 µg/mL, for CA, SCE, and MN tests; hydrogen peroxide-H2O2, 100 µM, for comet assay) were also maintained. MET significantly increased the frequency of CAs at 48 h exposure (except 12.5 µg/mL) compared to the negative control. MET increased SCEs/cells in both treatment periods (except 12.5 µg/mL at 24 h). MET only increased the frequency of MN at 125 µg/mL. While MET significantly increased the comet tail length (CTL) at four concentrations (25, 75, 100, and 125 µg/mL), it did not affect comet tail intensity (CTI) (except 125 µg/mL) and comet tail moment (CTM) at all the treatments. All these data showed that MET had a mild genotoxic effect, especially at a long treatment period and higher concentrations in human lymphocytes in vitro. However, further in vitro and especially in vivo studies should be conducted to understand the detailed genotoxic potential of MET.HighlightsMetformin increased the frequency of CAs and SCEs, especially at 48-h exposure time in human lymphocytes.This antidiabetic drug increased the frequency of MN only at the highest concentration tested (125 µg/mL).Metformin significantly increased the comet tail length in all treatments (except 50 µg/mL).The drug did not significantly affect the comet tail intensity (except 125 µg/mL) and comet tail moment in all treatments.

Investigation of genotoxic effects of rhododendron honey using three mammalian bioassays in vivo.

Rhododendron honey (RH) is obtained from the rhododendron plants are grown in many regions around the world, causes poisoning in humans due to the grayanotoxin (GTX) compound in its structure. It is used by the public as a therapeutic for some diseases. It was aimed to study the genotoxic and cytotoxic effects of RH in mouse bone-marrow and sperm cells by using three mammalian bioassays. 25, 50 and 75 mg kg-1 concentrations of RH given to male mice via gavage for 24 and 48 h treatment periods and its active ingredient Grayanatoxin (GTX-III) 0.01 mg kg-1 by i.p. injection. Chromosome aberrations (CA), polychromatic erythrocytes (PCE)/normochromatic erythrocytes (NCE), micronucleated polychromatic erythrocytes (MNPCE) and sperm abnormalities were investigated. The results demonstrated that all the tested concentrations of RH significantly induced total abnormal cell frequency including chromosomal breaks for two time periods. In the MN assay, 75 mg kg-1 RH and 0.01 mg kg-1 GTX-III significantly increased % MNPCE and significantly reduced PCE/NCE ratios after 24 and 48 h treatments on mice demonstrating potential genotoxic and cytotoxic effect. Although there was a concentration-related increase in the percentage of total sperm abnormalities, this increase was not statistically significant compared to control. As a result, microscopic genotoxicity and cytotoxicity marker tests showed that RH and its active ingredient GTX-III have potential genotoxic and cytotoxic effect on mice bone marrow cells. It is understood that RH that is used to treat some diseases by public, should be handled carefully and used in a controlled manner.HighlightsChromosome aberration, micronucleus and sperm morphology assays are recommended as reliable biological indicators.RH and its active ingredient GTX-III have potential genotoxic and cytotoxic effect on mice bone marrow cells.Significant changes were observed upon the treatment of 75 mg kg-1 MH for MN assay.