Frequency Of Nuclear Abnormalities Research Articles

Amelioration of Cytogenotoxic Damage in Drug Abusers Supplemented with Folic Acid.

Cytogenotoxic damage caused by the consumption of legal and illegal drugs in drug abusers has been demonstrated, primarily due to alterations in their antioxidant capacity, cellular repair mechanisms, and increased production of free radicals. Folic acid shows antioxidant activity by acting as a reducing agent, neutralizing present free radicals, and reducing genomic damage. The intervention involved administering 15 mg of folic acid, divided into three doses per day, to a group of 44 drug abusers. The frequency of nuclear abnormalities (NAs) was determined; micronuclei (MNs), nuclear buds (NBUDs), binucleated cells (BNs), abnormally condensed chromatin (CC), karyorrhexis (KX), pyknotic nuclei (PNs), and karyolysis (KL) were determined at different pre-treatment (baseline) and post-treatment time points at 15 and 30 days. Additionally, a group of 44 healthy individuals was used as the control group. We observed a statistically significant decrease in the frequency of NAs in the drug abuser group (28.45 ± 17.74 before supplementation vs. 11.18 ± 7.42 at 15 days and 9.11 ± 10.9 at 30 days of supplementation). Specifically, it decreased the frequency of NBUDs, BNs, CC, KX, and PNs (p < 0.05). Our study demonstrates a clear improvement in cytogenotoxic damage in drug abusers supplemented with folic acid.

Cytogenotoxicity effects in addicts with multidrug consumption.

Drug abuse is considered a global health problem with serious social impact. In recent decades, changes in drug consumption patterns have shown a clear rising trend in the use of multiple drugs. Although the buccal micronucleus cytome (BMCyt) assay has evaluated cytotoxicity in drug abuse, there has not been an approach that takes into account this pattern of multiple drug use. Therefore, in this study, we evaluate for the first time the cytogenotoxic effects in multidrug users, and its correlation with the amount consumed and years of abuse. This study was conducted on 166 individuals by the BMCyt assay. A total of 83 individuals with a history of multiple licit (alcohol and tobacco) and at least one illicit drug abuse (marijuana, methamphetamines, cocaine, and/or inhalants), and 83 healthy individuals, non-drug abusers were analyzed. The results showed that drug abusers had higher frequencies of nuclear abnormalities nuclear buds, binucleated cells, pyknotic nuclei (PNs), karyorrhexis (KX), and abnormally condensed chromatin when compared with healthy controls. Moreover, results suggests that the use of licit and illicit drugs is related to cytogenotoxic damage, as was shown by an upward trend in the frequency of nuclear abnormalities identified in groups 1 (alcohol + tobacco + at least one illicit drug) and 2 (tobacco + at least one illicit drug). Furthermore, a positive correlation was found in the different groups, between the years and the amount of consumption of some drugs (alcohol, methamphetamine, and tobacco) with cytotoxicity markers such as KL, KX, and PNs.

Cytogenotoxic potential and toxicity in adult Danio rerio (zebrafish) exposed to chloramine T

Background Chloramine-T (CL-T) is a synthetic sodium salt used as a disinfectant in fish farms to combat bacterial infections in fish gills and skin. While its efficacy in pathogen control is well-established, its reactivity with various functional groups has raised concerns. However, limited research exists on the toxicity of disinfection by-products to aquatic organisms. Therefore, this study aims to assess the sublethal effects of CL-T on adult zebrafish by examining biomarkers of nucleus cytotoxicity and genotoxicity, acetylcholinesterase (AChE) inhibition, and histopathological changes. Methods Male and female adult zebrafish (wildtype AB lineage) specimens were exposed to 70, 140, and 200 mg/L of CL-T and evaluated after 96 h. Cytotoxic and genotoxic effects were evaluated by estimating the frequencies of nuclear abnormalities (NA), micronuclei (MN), and integrated optical density (IOD) of nuclear erythrocytes. Histopathological changes in the gills and liver were assessed using the degree of tissue changes (DTC). AChE activity was measured in brain samples. Results and conclusions At a concentration of 200 mg/L, NA increased, indicating the cytogenotoxic potential of CL-T in adult zebrafish. Morphological alterations in the nuclei were observed at both 70 and 200 mg/L concentrations. Distinct IOD profiles were identified across the three concentrations. There were no changes in AChE activity in adult zebrafish. The DTC scores were high in all concentrations, and histological alterations suggested low to moderate toxicity of CL-T for adult zebrafish.

Metal bioaccumulation and genotoxicity in Oreochromis niloticus reared in farming pools influenced by mining activities in Napo, in the Ecuadorian Amazonia

Mining areas may suffer long-term metal contamination and represent harmful remnants of former mining activities. In the northern Amazon of Ecuador, former mining waste pits are used in Oreochromis niloticus (Nile tilapia) fish farming. Given the high consumption of this species by the local population, we aimed to estimate human consumption risks by determining Cd, Cu, Cr, Pb, and Zn tissue bioaccumulation (liver, gills, and muscle) and genotoxicity (micronucleus essay) in tilapia cultivated in one former mining waste pit (S3) and compare the findings to tilapias reared in two non-mining areas (S1 and S2); 15 fish total. Tissue metal content was not significantly higher in S3 than in non-mining areas. Cu and Cd were higher in the gills of tilapias from S1 compared to the other study sites. Higher Cd and Zn were detected in the liver of tilapias from S1 compared to the other sampling sites. Cu was higher in the liver of fish from S1 and S2, and Cr, in the gills of fish from S1. The highest frequency of nuclear abnormalities was observed in fish from S3, indicating chronic exposure to metals at this sampling site. The consumption of fish reared at the three sampling sites results in a 200-fold higher Pb and Cd ingestion than their maximum tolerable intake thresholds. Calculated estimated weekly intakes (EWI), hazard quotients (THQ), and Carcinogenic Slope Factors (CSFing) denote potential human health risks, indicating the need for continuous monitoring in this area to ensure food safety not only in areas affected by mining, but in general farms in the region.

Long-term exposure of zebrafish juveniles to carbon nanofibers at predicted environmentally relevant concentrations: Outspreading warns about ecotoxicological risks to freshwater fish

Although carbon-based nanomaterials (CNMs) toxicity has already been demonstrated in some animal models, little is known about the impact of carbon nanofibers (CNFs) on aquatic vertebrates. Thus, we aimed to evaluate the possible effects of long-term exposure of zebrafish (Danio rerio) juveniles (90 days) to CNFs in predicted environmentally relevant concentrations (10 ng/L and 10 μg/L). Our data revealed that exposure to CNFs did not affect the growth and development of the animals, in addition to not having induced locomotor alterations or anxiety-like behavior. On the other hand, we observed that zebrafish exposed to CNFs showed a response deficit to the vibratory stimulus test, alteration in the density of neuromasts recorded in the final ventral region, as well as an increase in thiobarbituric acid reactive substances levels and a reduction in total antioxidant activity, nitric oxide, and acetylcholinesterase activity in the brain. Such data were directly associated with a higher concentration of total organic carbon in the brain, which suggests the bioaccumulation of CNFs. Furthermore, exposure to CNFs induced a picture suggestive of genomic instability, inferred by the increased frequency of nuclear abnormalities and DNA damage in circulating erythrocytes. Although the individual analyses of the biomarkers did not point to a concentration-dependent effect, the principal component analysis (PCA) and the Integrated Biomarker Response Index (IBRv2) indicate a more prominent effect induced by the higher CNFs concentration (10 μg/L). Therefore, our study confirms the impact of CNFs in the studied model (D. rerio) and sheds light on the ecotoxicological risks of these nanomaterials to freshwater fish. Based on the ecotoxicological screening provided by our study, new horizons are opened for investigations into the mechanisms of action of CNFs, which will help understand the magnitude of the impact of these materials on aquatic biota.

Clinical Hematology of the Nose-Horned Viper, Vipera ammodytes (Linnaeus 1758)

The establishment of hematological profiles of animals taken from their natural environment or kept in captivity has great importance in determining the health status and biology of these species. Pollution in the habitat of reptiles and the impact of various diseases can be determined by analyzing blood parameters. In this study, the clinical hematology (erythrocyte and leukocyte count, erythrocyte types, differential blood formula, hemoglobin, hematocrit, mean corpuscular volume, mean corpuscular hemoglobin, mean corpuscular hemoglobin concentration) of three Nose-horned Vipers (Vipera ammodytes) captured from Vize (Kırklareli, Türkiye) were examined. We detected the frequency of nuclear abnormalities in this species for the first time. We also provide the first erythrometric measurements of Vipera ammodytes, and found that the erythrocyte sizes of this species were larger compared to other species in Viperidae. Knowledge of the general health status of animals is important in species conservation action plans and monitoring studies.

De Novo Germline DHX38 Variant Associated with Alternative Splicing of Multiple Transcripts in Iron-Related Pathways in a Patient with Atypical Congenital Dyserythropoietic Anemia with Ring Sideroblasts

Congenital Dyserythropoietic Anemias (CDAs) are a heterogeneous group of rare hereditary anemias caused by ineffective and dyspoietic erythropoiesis, with the pathognomonic feature of binuclear and/or multinuclear erythroid precursors in the bone marrow. The clinical diagnosis of CDA is based on identifying the characteristic morphology of erythroblasts in the bone marrow of patients presenting with chronic anemia, frequently with evidence of hemolysis but suboptimal reticulocytosis, and iron overload. CDAR (ClinicalTrials.gov identifier: NCT02964494), a registry for patients with CDA in North America, has been established with the goal of providing a longitudinal database and associated biorepository to facilitate natural history studies and research on the pathogenetic mechanisms in this heterogenous disease. A 2-year-old female, enrolled in CDAR, had transfusion-dependent anemia since birth. She demonstrated accelerated iron overload and had failure to thrive despite regular transfusions maintaining trough hemoglobin higher than 9.5 g/dL. Bone marrow evaluation revealed dyserythropoiesis along with ring sideroblasts (RS), resembling acquired myelodysplastic syndrome (MDS) with the characteristics of Refractory Anemia with RS (RARS). Whole-exome sequencing for the proband and her parents in trio analysis identified a de novo, heterozygous germline DHX38 missense variant c.3310A>C, p.Thr1104Pro in the proband. In silico prediction programs suggest this rare variant is deleterious. DEAH box RNA helicase DHX38 is an RNA helicase, homolog to the yeast Prp16 that has been shown to play a dual role in the spliceosome complex: an ATP-independent role in the first catalytic step mediating proofreading of the branchpoint sequence, and an ATP-dependent role in the second step, mediating removal of the lariat and joining the exons to complete the splicing (Tseng et al, RNA 2011). DHX38 is highly expressed during terminal erythropoiesis similarly to SF3B1, the splicing factor gene most frequently mutated in MDS-RARS. RNA-seq analysis of CD71+ reticulocytes isolated from the proband at three different time points compared to three different normal control samples, using AltAnalyze software, revealed approximately 3,000 differentially expressed genes. More than 1,500 differentially spliced events were identified, affecting over 200 genes, including SLC25A37, coding for an iron importer localized in the mitochondrial inner membrane and PPOX, coding for protoporphyrinogen oxidase (Figure 1A), both essential for the synthesis of mitochondrial heme. Mis-splicing of the same genes is a characteristic finding in MDS-RARS associated with SF3B1 pathogenic variants, most commonly p.Lys700Glu, and may contribute to RS formation. Moreover, DHX38 is known to interact with centromeric noncoding RNA, regulating chromosome segregation during mitosis, and its depletion in vitro causes abnormal grape-shaped nuclear morphology (Nishimura et al, Genes Cells 2019). Review of the patient's bone marrow studies revealed several erythroblasts with grape-shaped nuclei (Figure 1B). Erythropoiesis cultures from patient-derived iPSCs were utilized to phenocopy the disease in vitro. Cytospins of the generated erythroblasts revealed dyserythropoiesis that was verified quantitatively by increased frequency of nuclear abnormalities in erythroblasts produced in vitro from patient-derived iPSCs analyzed by imaging flow cytometry. Extra-hematopoietic abnormalities of the nucleus and mitotic defects were explored in fibroblasts generated from the patient's skin biopsy, which also tested positive for DHX38 p.Thr1104Pro. Grape-shaped nuclei were detected in cultures of patient's fibroblasts indicating improper mitotic exit due to aberrant chromosome segregation. Our findings indicate that DHX38 is likely the causative gene for this CDA with a RARS phenotype, causing mis-splicing of a multitude of genes critical for iron metabolism and erythropoiesis as well as defects in chromosome segregation and cell division. Out of approximately 250,000 alleles in the gnomAD database, the DHX38 p.Thr1104Pro variant has been detected in 4 alleles; however, SF3B1 p.Lys700Glu is also detected in 22. Therefore, the rare presence of this DHX38 variant in "healthy" population may indicate that acquired DHX38 pathogenic variants exist and could be responsible for SF3B1-negative MDS-RARS. Figure 1View largeDownload PPTFigure 1View largeDownload PPT Close modal

Ecotoxicological effects of conventional herbicides and a natural herbicide on freshwater fish (Danio rerio)

The contamination of aquatic environments has increased over time, affecting environmental integrity and human health. Herbicides represent a source of this contamination, and among the most commercialized are the triazines and glyphosate. In contrast, there are natural herbicides, which are less harmful to the environment. The aim of this study was to verify the ecotoxicological effects of the conventional herbicides (Atrazine and Glyphosate) and a natural herbicide on Zebrafish (Danio rerio). Fish were exposed for 72 h to different concentrations of conventional herbicides (1, 65, and 5,000 µg L−1) and the natural herbicide (0.62, 1.25, and 2.5 µg L−1) in aquaria (20 L). At end of the experiment, blood was collected from the fish, and slides were prepared to verify the frequency of nuclear abnormalities and micronuclei. A greater number of morphological nuclear alterations were recorded in the conventional herbicide treatments. In addition, significant differences were observed in the composition of abnormalities between treatments. Atrazine and Glyphosate can cause greater damage in D. rerio, demonstrating potential toxicity at all concentrations applied. The natural herbicide showed less mutagenic potential and was less harmful to fish. Thus, natural herbicides can be a better option for the preservation of the environment.

Influence of temperature on biomarker responses of bullfrog tadpoles (Lithobates catesbeianus) exposed to the herbicide ametryn

The S-triazine herbicide ametryn (AMT) is relatively low adsorbed in soils and has high solubility in water, thus believed to affect non-target aquatic organisms such as amphibians. Temperature increases can intensify the effects of herbicides, possibly increasing the susceptibility of amphibians to these compounds. The aim of this study was to evaluate the influence of temperature (25 and 32 °C) on the responses of biochemical biomarkers in bullfrog tadpoles (Lithobates catesbeianus) exposed to different concentrations of AMT (0, 10, 50 and 200 ng.L−1) for a period of 16 days. The antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD) and the biotransformation enzyme glutathione S-transferase (GST) had their activity decreased at the highest temperature (32 °C). SOD activity was reduced at 200 ng.L−1 and 32 °C compared to the control at the same temperature. AMT exposure also decreased the activities of alanine aminotransferase and gamma glutamyl transferase. On the other hand, the activities of acetylcholinesterase, carboxylesterase, alkaline phosphatase, levels of lipid peroxidation and protein carbonyl, as well genotoxic markers (micronucleus and nuclear abnormalities frequencies) were unchanged. The evaluation of integrated biomarker response index (IBR) indicated highest variations at the concentration of 200 ng.L−1 at 32 °C, suggesting that the combination of high AMT concentrations and temperatures generate more pronounced negative effects to tadpoles.

Fish feed can show genotoxic damage.

The present study was carried out to evaluate the genotoxic potential of nutritional quality of feed, using erythrocytic nuclear abnormalities assay in Nile tilapia and its correlation with available nutrients and common fish growth biomarkers. For this, ten feeds commercialized in Brazil were assessed on digestibility and performance assays with triplicate groups. Venipuncture of the caudal vein for abnormalities analyzed was performed 102days after the fish were fed with the commercial feed twice a day, to apparent satiation. Nuclear abnormalities were analyzed in blood smears. Principal component analysis and correlation matrix were used to carry out an exploratory analysis of correlation between frequency of abnormalities and performance parameters or available nutrients. The frequency of abnormalities in erythrocytes of Nile tilapia, fish performance, and digestibility were feed-dependent. It was observed correlations between the frequency of most abnormalities and performance parameters or content of nutrients. The frequency of kidney-shaped (6.23 ± 4.14), bud nuclei (2.99 ± 1.95), bridge nuclei (0.53 ± 0.50), and binuclei (0.43 ± 0.59) was the highest in fish that also presented the worst performance among all treatments and correlated with digestible methionine. Micronucleus frequency (0.33 ± 0.49) was higher in fish from the same group that presented depressed feed intake and lower available zinc. Only one group presented vacuolated nuclei and the frequency of this abnormality was correlated with available phosphorus. The frequency of abnormalities in erythrocytes is a fish sensitive indicator of health and plays an important role as a complementary tool in the assessment of fish feeding. The variation in the frequency of nuclear abnormalities in erythrocytes obtained among fish fed with the different feeds allows the assertion that they contained genotoxic factors.

Nuclear abnormalities and Oxidative Stress Induced by Hookah (Shisha) in Male Human in Erbil City

Nowadays hookah smoking has dramatically increased especially in the Middle East. Because Hookah tobacco contains many harmful substances, it has dangerous impacts on human beings. The goal of the current study is to examine the oxidative stress in blood and clastogenic effects of hookah smoking on exfoliated buccal cells. One hundred and twenty five healthy adult males were involved in this study. The participants were distributed into five groups: control, passive smokers, and three hookah smoker groups. Samples of blood from all groups were examined for Malondialdehyde (MDA) level and exfoliated buccal cells were aslo examined thorough micronucleus (MN) test for frequencies of nuclear abnormalities including Micronucleus (MN), Binucleates (BN) and Karyolysis (KL), were evaluated as well. frequencies of all nuclear abnormalities Micronucleus (MN), Binucleates (BN) and Karyolysis significantly increased in all exposed groups compared to the control group and the effect was exposure duration dependent. Malondialdehyde level also significantly increased in all exposed groups compared to the control group and the effect was exposure duration dependent.

A comprehensive approach using multiple biomarkers to detect damage induced by pesticides in broad-snouted caiman (Caiman latirostris) under ex-situ conditions

Caiman latirostris is one of the two species of the order Crocodylia that inhabit Argentina and is considered a species of vital ecological and economic importance in the north-east of Argentina. In this region, pesticides are the most common contaminants in natural environments and wild caiman populations are subject to this contamination constantly. The aim of this study was to evaluate the effects the main pesticides used in the region: glyphosate (GLY), cypermethrin (CYP) and chlorpyrifos (CPF) -based formulations, as well as the mixture of them, on C. latirostris juveniles under semi-controlled condition of exposure (ex-situ) during 75 days. One hundred yearling caimans (10-month-old) were equally distributed into five experimental groups (20 animals per group): a negative control (NC -tap water), GLY 2% (Roundup® Full II formulation -RU), CYP 0.12% (Atanor® formulation), CPF 0.8% (Lorsban® formulation), and a mixture of the three pesticides (Mx3: GLY 2% + CYP 0.12% + CPF 0.8%). We applied early warning biomarkers to detect damage induced by these chemicals in peripheral blood: activity of the antioxidant enzymes catalase (CAT) and superoxide dismutase (SOD), analysis of lipid peroxidation (LPO) by the thiobarbituric acid reactive substances (TBARS), DNA damage and specific base oxidation through the standard and modified comet assay (CA), chromosome damage by micronucleus (MN) test and other nuclear abnormalities (NAs), hematological and growth parameters. Results showed a statistically significant increase in MN and NAs frequency, DNA damage, with an important contribution of base oxidation for all exposed groups compared to the NC. Total white blood cells count (TWBCC), and growth parameters showed effects mainly at the Mx3. The principal component analysis (PCA) demonstrated more sensitivity for biomarkers associated to genetic damage, including base oxidation to DNA than LPO, antioxidant enzyme modulation, immunotoxicity or growth parameters, to detect pesticides effects, applied under conditions similar to that found in natural environments.

Evaluation of genotoxicity in bat species found on agricultural landscapes of the Cerrado savanna, central Brazil

Habitat loss and fragmentation together represent the most significant threat to the world's biodiversity. In order to guarantee the survival of this diversity, the monitoring of bioindicators can provide important insights into the health of a natural environment. In this context, we used the comet assay and micronucleus test to evaluate the genotoxic susceptibility of 126 bats of eight species captured in soybean and sugarcane plantation areas, together with a control area (conservation unit) in the Cerrado savanna of central Brazil. No significant differences were found between the specimens captured in the sugarcane and control areas in the frequency of micronuclei and DNA damage (comet assay). However, the omnivore Phyllostomus hastatus had a higher frequency of nuclear abnormalities than the frugivore Carollia perspicillata in the sugarcane area. Insectivorous and frugivorous bats presented a higher frequency of genotoxic damage than the nectarivores in the soybean area. In general, DNA damage and micronuclei were significantly more frequent in agricultural environments than in the control area. While agricultural development is an economic necessity in developing countries, the impacts on the natural landscape may result in genotoxic damage to the local fauna, such as bats. Over the medium to long term, then DNA damage may have an increasingly negative impact on the wellbeing of the local species.

Combination of Water Quality Parameters and Bioassays for the Assessment of Two Rivers, Southern Brazil.

In the present study, water physicochemical and microbiological parameters, as well as bioassays using Allium cepa L. seeds and the fish species Astyanax jacuhiensis were used to assess the water quality of two rivers - Ilha River and Paranhana River -, located in southern Brazil. Water samples were collected at the source and mouth of the rivers and then, laboratory experiments were performed. The results evidenced high levels of aluminum and iron in water samples collected at the four sampling sites. The micronucleus (MN) test in fish showed significant difference in the frequencies of nuclear abnormalities (NA) in the mouth of the Paranhana River in comparison to control group in one sampling period, whereas the A. cepa test evidenced significant spatial differences in cytotoxicity between the source and mouth of both rivers. Therefore, these data evidence the poor water quality of the rivers studied as well as the potential toxicity to the aquatic organisms.

ANALISIS SITOGENETIK SEL EPITEL MUKOSA BUKAL PEKERJA STASIUN PENGISI BAHAN BAKAR UMUM DI KOTA YOGYAKARTA

Workers employed in petroleum station have a high-risk exposure to a wide range of toxic compounds with known mutagenic and carcinogenic potential. Cytogenetic damage might have happened if they continuously exposed to petroleum derivatives. This study aimed to analyse the cytogenetic damage in exfoliated buccal cells among petroleum station workers in Yogyakarta City. This cross-sectional study was carried out on 30 petrol station workers who are working at a different petrol station in Yogyakarta and the control group consisted of 30 healthy subjects. Examination for all subjects included frequencies of nuclear abnormalities, including pycnosis, karyorrhexis, and karyolysis. Cytological preparations were stained according to papanicolaou reaction and analyzed under light microscope for making a score for degenerative nuclear alterations (pycnosis, karyolysis and karyorrhexis). Analysis of buccal cells revealed that frequencies of pycnosis and karyorrhexis in petrol station workers were significantly higher than the control group (P&lt;0.05). Conversely, there was no significant difference in karyolisis among groups. These findings indicate that the petrol station workers are under the risk of significant cytogenetic damage, particularly pycnosis and karyorrhexis.

Genotoxic effects of urban pollution in the Iguaçu River on two fish populations

Environmental impacts on water resources and discharges of pollutants are some of the main problems of aquatic ecosystems. Currently, the Iguaçu River is considered the second most polluted river in Brazil, therefore, given the importance of understanding the effects of water pollution on living organisms, this study aimed to analyze the possible genotoxic effects in Astyanax bifasciatus (Characiformes; Characidae) and Geophagus brasiliensis (Perciformes: Cichlidae) in response to the water quality of the Iguaçu River. Four sampling points were determined on the Iguaçu River, with different levels of environmental impact. The micronuclei and nuclear abnormalities were quantified by counting 2000 erythrocytes from each specimen. There was a statistical difference in the frequency of nuclear abnormalities both for A. bifasciatus (Kruskal-Wallis 3;30 = 10.9; p = 0.01) and for G. brasiliensis (Kruskal-Wallis 3;26 = 12.27; p = 0.006), with point 1 (critically degraded) showing a higher frequency of nuclear abnormalities and point 4 (moderately degraded) showing a lower frequency of nuclear abnormalities for both species, showing genotoxic potential in fish erythrocytes. This result demonstrates the need for further discussion on the conservation of the Iguaçu River as well as broadening the discussion on its potability.

Cytogenetic analysis of nuclear abnormalities in the erythrocytes of gecko lizards (Phyllopezus periosus) collected in a semi-arid region of northeast Brazil: Possible effects of natural background radioactivity

High natural-background radioactivity levels occur in the semi-arid region of the State of Rio Grande do Norte, northeastern Brazil. We have studied the lizard Phyllopezus periosus, an endemic species of the Brazilian caatinga with saxicolous habitat, as a bioindicator of environmental quality. Specimens were collected in three areas, an environmental protection area and two areas recognized as having high natural background radiation, one of these being a mining area. Level of metals and gamma radiation emitters present in the water sources potentially used by the lizards were measured. The biological endpoints assessed were micronuclei and nuclear abnormalities in blood samples. Significant differences in background radioactivity levels were found among the assessed areas. Statistically significant differences in micronuclei and nuclear abnormality frequencies were seen, among the study areas and a relationship between radioactivity level and genetic damage was observed.

Cytogenotoxicity Evaluation of Young Adults Exposed to High Levels of Air Pollution in a Mexican Metropolitan Zone Using Buccal Micronucleus Cytome Assay

Air pollution has become a serious public health problem globally. Recent studies support the harmful effect of air pollution on human health, in addition to scientific evidence that recognizes it as a human carcinogen. The buccal micronucleus cytome (BMC) assay is employed extensively to measure cytotoxic and genotoxic damage in a population exposed to environmental contamination. The objective of this study was to evaluate the cytotoxic and genotoxic effects in healthy young adults exposed to different levels of air pollution and to identify areas with air pollution rates above the regulatory limits. This study was performed through the BMC assay in oral mucosa samples from 80 healthy young adults from the Guadalajara metropolitan zone. Three highly contaminated areas were taken into account: Tlaquepaque, Miravalle, and Las Pintas. Las Aguilas, a less contaminated area, was used as a reference. The frequencies of nuclear abnormalities in the areas with the highest and lowest levels of air pollution were compared with the Mann–Whitney U test. In addition, an analysis of the concentration of environmental pollutants, particulate matter ≤ 10 μm (PM10), ozone (O3), nitrogen dioxide (NO2), sulfur dioxide (SO2), and carbon monoxide (CO), were carried out in the mentioned areas, in order to identify the events above the regulatory limits in a year period. The results showed that young adults exposed to a higher concentration of pollutants showed higher frequencies of nuclear abnormalities. The individuals from the areas of Tlaquepaque, Miravalle, and Las Pintas showed cytotoxic damage since statistically significant differences were found in the abnormalities of pyknotic nuclei (PNs), condensed chromatin (CC), karyorrhexis (KX), and karyolysis (KL). The individuals who showed the most cytotoxic damage were from the Las Pintas area with higher frequencies in nuclear abnormalities (PNs, CC, KX, and KL) (p < 0.0001). Genotoxic damage was found in individuals from two zones, Miravalle and Las Pintas, with statistically significant differences in the abnormality of nuclear buds (NBUDs) (p < 0.0001). Our results suggest that exposure to high levels of air pollution in healthy young adults has an effect on cellular and nuclear integrity and thus in human health, since areas with higher air pollution showed an increase in cytotoxicity, specifically in early and late markers of cell death (CC, KX, PN, and KL) and genotoxic damage (BUDs).

Genotoxic and melanic alterations in Lithobates catesbeianus (anura) tadpoles exposed to fipronil insecticide.

The aim of this study was to evaluate the genotoxic and morphological systemic effects of both an acute and a chronic exposure of bullfrog tadpoles to fipronil. Lithobates catesbeianus tadpoles had morphological biomarkers (skin, liver, and blood) analyzed at Gosner stages 36-38, when exposed to four different concentrations of Regent® 800 WG (80% fipronil): 0.00 (control), 0.04, 0.08, 0.4 mg/L, and four experimental times: 4, 8, 12, and 16 days. Body darkness responded directly to the treatment and exposure time. There was a treatment-dependent decrease in darkness of heads and tails. In relation to the biometric analysis, fipronil induced a decrease in the individual weight and liver mass at the end of the experiments, whereas the hepatosomatic index did not vary according to the treatment. For the exposed animals and for the control group, the area of hepatic melanin increased as exposure time increased. Fipronil has genotoxic effects on L. catesbeianus tadpoles even after short exposure times (e.g., 4 and 8 days), and the main nuclear abnormality is in the anucleate cells. A relevant correlation was observed between genotoxic biomarkers and cutaneous and internal melanin. The frequency of nuclear abnormalities is inversely correlated both with the hepatic melanin area and with the cutaneous melanin of animals. Fipronil has distinct systemic effects on tadpoles based on its concentration, as well as on its exposure time. Such alterations (pigmentation level and rate of erythrocyte abnormality) result in morphological and physiological effects, which may compromise the behavior and survival of the anurans.

Nuclear abnormalities in umbilical cord blood lymphocytes of newborns from the Ahome and Guasave municipalities in Sinaloa, Mexico.

We measured the frequency of nuclear abnormalities of 210 blood samples from the umbilical cord, since human fetuses are exposed to environmental mixtures of pesticides that induce DNA damage. The determinations were made through the micronucleus assay test in lymphocytes from the umbilical cord blood of newborns whose mothers live in Ahome (n = 105) and Guasave (n = 105), Sinaloa, Mexico. The average frequency of anomalies in 1000 cells were, respectively: micronucleus 0.4 vs. 2.9, pyknotic cells 18.3 vs. 109.2, chromatin condensation 7.7 vs. 150.1, karyolitic cells 1.8 vs. 24.4, and binucleated cells 4.9 vs. 74.6. The calculated Pearson correlation factors of nuclear abnormality frequencies between both municipalities were low and negative, suggesting that they did not correlate between the Ahome and Guasave newborns and indicating a higher number of mothers exposed in Guasave. Our data suggest that monitoring nuclear abnormalities in umbilical cord blood samples could be a useful tool to identify transplacental mutagens perfusion that is being discharged into the local environment.