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Sample records for 2-glucocide reduces micronucleus

  1. [Micronucleus test: cytome assay and health biomarker].

    PubMed

    García Sagredo, José Miguel

    2012-01-01

    Micronuclei are structures similar to a nucleus but small size and localized in the cytoplasm. A micronucleus contents chromosome fragments or whole chromosomes. The micronucleus test is considered a biomarker for early induced genetic damage. Micronucleus test with cytochalasin B (CBMN test) is used to evaluate genotoxic effects induced by physical and chemical environmental agents, and to estimate the genetic damage induced in population groups exposed to such agents. After the study of large groups of control population, it is estimated that CBMN test can be used as a marker of health status with ability to establish a cancer risk. Finally, recent studies about the onset of cancer, based on single catastrophic events able to originate a cancer, such as chromothripsis or chromoanagenesis, are going to understand through an anomalous replication of DNA within the micronucleus.

  2. 900 MHz radiation does not induce micronucleus formation in different cell types.

    PubMed

    Hintzsche, Henning; Jastrow, Christian; Kleine-Ostmann, Thomas; Schrader, Thorsten; Stopper, Helga

    2012-07-01

    The exposure of the population to non-ionising electromagnetic radiation is still increasing, mainly due to mobile communication. Whether low-intensity electromagnetic fields can cause other effects apart from heating has been a subject of debate. One of the effects, which were proposed to be caused by mobile phone radiation, is the occurrence of mitotic disturbances. The aim of this study was to investigate possible consequences of these mitotic disturbances as manifest genomic damage, i.e. micronucleus induction. Cells were irradiated at a frequency of 900 MHz, which is located in one of the main frequency bands applied for mobile communication. Two cell types were used, HaCaT cells as human cells and A(L) cells (human-hamster hybrid cells), in which mitotic disturbances had been reported to occur. After different post-exposure incubation periods, cells were fixed and micronucleus frequencies were evaluated. Both cell types did not show any genomic damage after exposure. To adapt the protocol for the micronucleus test into the direction of the protocol for mitotic disturbances, the post-exposure incubation period was reduced and exposure time was extended to one cell cycle length. This did not result in any increase of the genomic damage. In conclusion, micronucleus induction was not observed as a consequence of exposure to non-ionising radiation, even though this agent was reported to cause mitotic disturbances under similar experimental conditions.

  3. Evaluation of a multi-endpoint assay in rats, combining the bone-marrow micronucleus test, the Comet assay and the flow-cytometric peripheral blood micronucleus test.

    PubMed

    Bowen, Damian E; Whitwell, James H; Lillford, Lucinda; Henderson, Debbie; Kidd, Darren; Mc Garry, Sarah; Pearce, Gareth; Beevers, Carol; Kirkland, David J

    2011-05-18

    With the publication of revised draft ICH guidelines (Draft ICH S2), there is scope and potential to establish a combined multi-end point in vivo assay to alleviate the need for multiple in vivo assays, thereby reducing time, cost and use of animals. Presented here are the results of an evaluation trial in which the bone-marrow and peripheral blood (via MicroFlow(®) flow cytometry) micronucleus tests (looking at potential chromosome breakage and whole chromosome loss) in developing erythrocytes or young reticulocytes were combined with the Comet assay (measuring DNA strand-breakage), in stomach, liver and blood lymphocytes. This allowed a variety of potential target tissues (site of contact, site of metabolism and peripheral distribution) to be assessed for DNA damage. This combination approach was performed with minimal changes to the standard and regulatory recommended sampling times for the stand-alone assays. A series of eight in vivo genotoxins (2-acetylaminofluorene, benzo[a]pyrene, carbendazim, cyclophosphamide, dimethylnitrosamine, ethyl methanesulfonate, ethyl nitrosourea and mitomycin C), which are known to act via different modes of action (direct- and indirect-acting clastogens, alkylating agents, gene mutagens, cross-linking and aneugenic compounds) were tested. Male rats were dosed at 0, 24 and 45 h, and bone marrow and peripheral blood (micronucleus endpoint), liver, whole blood and stomach (Comet endpoint) were sampled at three hours after the last dose. Comet and micronucleus responses were as expected based on available data for conventional (acute) stand-alone assays. All compounds were detected as genotoxic in at least one of the endpoints. The importance of evaluating both endpoints was highlighted by the uniquely positive responses for certain chemicals (benzo[a]pyrene and 2-acetylaminofluorene) with the Comet endpoint and certain other chemicals (carbendazim and mitomycin C) with the micronucleus endpoint. The data generated from these

  4. Antigenotoxicity of artepillin C in vivo evaluated by the micronucleus and comet assays.

    PubMed

    de Azevedo Bentes Monteiro Neto, Moacir; de Souza Lima, Ildercílio Mota; Furtado, Ricardo Andrade; Bastos, Jairo Kenupp; da Silva Filho, Ademar Alves; Tavares, Denise Crispim

    2011-11-01

    Artepillin C (3,5-diprenyl-p-coumaric acid), a major compound found in Brazilian green propolis and Baccharis dracunculifolia, shows anti-inflammatory, antibacterial, antiviral, antioxidant and antitumoral activities, among others. The aim of this study was to evaluate the genotoxic potential of artepillin C and its ability to prevent the chemically induced chromosome breakage or loss and the primary DNA damage using the micronucleus and comet assays in male Swiss mice, respectively. The animals were treated by gavage with different doses of artepillin C (0.4, 0.8 and 1.6 mg kg(-1) b.w.). For the antigenotoxicity assays, the different doses of artepillin C were administered simultaneously to doxorubicin (DXR; micronucleus test; 15 mg kg(-1) b.w.) and to methyl methanesulfonate (MMS; comet assay; 40 mg kg(-1) b.w.). The results showed that artepillin C itself was not genotoxic in the mouse micronucleus and comet assays. In the animals treated with artepillin C and DXR, the number of micronucleated reticulocytes was significantly lower in comparison with the animals treated only with DXR. Regarding antigenotoxicity, artepillin C at the tested doses significantly reduced the extent of DNA damage in liver cells induced by MMS.

  5. Role of micronucleus in oral exfoliative cytology

    PubMed Central

    Shashikala, R.; Indira, A. P.; Manjunath, G. S.; rao, K. Arathi; Akshatha, B. K.

    2015-01-01

    In the last few years, the interest for oral cytology as a diagnostic and prognostic methodology, for monitoring patients in oral potentially malignant disorders and oral cancer has re-emerged substantially. In 1983, buccal mucosal micronuclei assay was first proposed to evaluate genetic instability. There are biomarkers that predict if a potentially malignant disorder is likely to develop into an aggressive tumor. These genotoxic and carcinogenic chemicals have been reported to be potent clastogenic and mutagenic agents which are thought to be responsible for the induction of chromatid/chromosomal aberrations resulting in the production of micronuclei. Various studies have concluded that the gradual increase in micronucleus (MN) counts from normal oral mucosa to potentially malignant disorders to oral carcinoma suggested a link of this biomarker with neoplastic progression. MN scoring can be used as a biomarker to identify different preneoplastic conditions much earlier than the manifestations of clinical features and might specifically be exploited in the screening of high-risk population for a specific cancer. Hence, it can be used as a screening prognostic and educational tool in community centers of oral cancer. PMID:26538888

  6. 40 CFR 798.5395 - In vivo mammalian bone marrow cytogenetics tests: Micronucleus assay.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... cytogenetics tests: Micronucleus assay. 798.5395 Section 798.5395 Protection of Environment ENVIRONMENTAL... Genetic Toxicity § 798.5395 In vivo mammalian bone marrow cytogenetics tests: Micronucleus assay. (a) Purpose. The micronucleus test is a mammalian in vivo test which detects damage of the chromosomes...

  7. Micronucleus formation during chromatin condensation and under apoptotic conditions.

    PubMed

    Kiraly, Gabor; Simonyi, Athene S; Turani, Melinda; Juhasz, Istvan; Nagy, Gabor; Banfalvi, Gaspar

    2017-02-01

    In early S phase the newly replicated DNA is folded back to increasingly compact structures. The process of chromatin condensation inside the nucleus starts with the formation of a micronucleus observed in five established cell lines (K562, CHO, Indian muntjac, murine preB and SCC). Supercoiling of chromatin generates a polarized end-plate region extruded from the nucleus. The extruded chromatin is turned around itself forming the head portion (micronucleus) visible by fluorescence microscopy until the middle of S phase when chromatin structures are succeeded by distinguishable early forms of chromosomes. The generation of micronuclei upon apoptotic treatment was achieved by the methotrexate (MTX) treatment of cells. A close correlation was found between the frequency of micronucleus and MTX concentration, with low frequency at low (0.1 µM) and increasingly higher frequency between 1 and 100 µM concentrations. Characteristic deformation and shrinkage of nuclei indicated apoptosis. High MTX concentration (100 µM) caused the enlargement and necrotic disruption of nuclei. Inhibition of DNA synthesis during replicative DNA synthesis by biotinylated nucleotide prevented the formation of metaphase chromosomes and elevated the frequency of early intermediates of chromosome condensation including micronucleus formation. Based on these observations the micronucleus is regarded as: (a) a regularly occuring element of early chromatin condensation and (b) a typical sign of nuclear membrane damage under toxic conditions. Explanation is given why the micronucleus is hidden in nuclei under normal chromatin condensation and why chromatin motifs including micronuclei become visible upon cellular damage.

  8. What Can a Micronucleus Teach? Learning about Environmental Mutagenesis

    ERIC Educational Resources Information Center

    Linde, Ana R.; Garcia-Vazquez, Eva

    2009-01-01

    The micronucleus test is widely employed in environmental health research. It can also be an excellent tool for learning important concepts in environmental health. In this article we present an inquiry-based laboratory exercise where students explore several theoretical and practical aspects of environmental mutagenesis employing the micronucleus…

  9. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Al Pellom “User's guide: Micronucleus assay data management and analysis system”, NTIS Order no. PB.... (i) All data developed within this study shall be in accordance with good laboratory practice... separately. (e) Data and report—(1) Treatment of results. In addition to the reporting requirements...

  10. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Al Pellom “User's guide: Micronucleus assay data management and analysis system”, NTIS Order no. PB.... (i) All data developed within this study shall be in accordance with good laboratory practice... separately. (e) Data and report—(1) Treatment of results. In addition to the reporting requirements...

  11. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Al Pellom “User's guide: Micronucleus assay data management and analysis system”, NTIS Order no. PB.... (i) All data developed within this study shall be in accordance with good laboratory practice... separately. (e) Data and report—(1) Treatment of results. In addition to the reporting requirements...

  12. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Al Pellom “User's guide: Micronucleus assay data management and analysis system”, NTIS Order no. PB.... (i) All data developed within this study shall be in accordance with good laboratory practice... separately. (e) Data and report—(1) Treatment of results. In addition to the reporting requirements...

  13. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Al Pellom “User's guide: Micronucleus assay data management and analysis system”, NTIS Order no. PB.... (i) All data developed within this study shall be in accordance with good laboratory practice... separately. (e) Data and report—(1) Treatment of results. In addition to the reporting requirements...

  14. Rodent Bone Marrow Micronucleus Assay. Test Substance: Solvent Yellow 33 2-(2-Quinolyl)-1,3-indandione

    DTIC Science & Technology

    2011-01-18

    COVERED 4. TITLE AND SUBTITLE Rodent Bone Marrow Micronucleus Assay Test Substance, Solvent Yellow 33 2-(2-Quinolyl)-1,3-indandione 5a. CONTRACT...Assay (Negative Control) 48 hours: Body Weights, Dosing Data, Clinical Observations, and Micronucleus Scoring Data Micronucleus Assay ( Test Substance...2000 mg/kg Body Weight) 24 hours: Body Weights, Dosing Data, Clinical Observations, and Micronucleus Scoring Data Micronucleus Assay ( Test Substance

  15. Micronucleus assay as a biomarker of genotoxicity in the occupational exposure to agrochemicals in rural workers.

    PubMed

    Gentile, N; Mañas, F; Bosch, B; Peralta, L; Gorla, N; Aiassa, D

    2012-06-01

    This paper aims to evaluate the genotoxic effect of agrochemicals in rural workers occupationally exposed by the micronucleus assay in peripheral blood lymphocytes and to promote the development of health and environmental preventive and protective practices. A total of 30 blood samples from 20 individuals occupationally exposed to different agrochemicals and 10 unexposed persons, who formed the reference group, were analyzed. We found statistically significant differences (p < 0.0005, Student's t Test) in the frequency of micronuclei between the two groups (7.20 ± 1.55 and 15.15 ± 5.10 CBMN for reference and exposed groups respectively). The analysis of age showed a positive correlation (Pearson Correlation Test) with the frequency of micronuclei in exposed population (p < 0.05; r(2) = 0.47), in contrast with smoking habits and years of exposure. Micronucleus assay allows an early detection of populations at higher risk of having genetic damage, allowing us to implement strategies of intervention for the purpose of contributing to reduce that risk.

  16. Buccal Micronucleus Cytome Assay in Sickle Cell Disease

    PubMed Central

    Naga, Mallika Bokka Sri Satya; Gour, Shreya; Nallagutta, Nalini; Velidandla, Surekha; Manikya, Sangameshwar

    2016-01-01

    Introduction Sickle Cell Anaemia (SCA) is a commonly inherited blood disorder preceded by episodes of pain, chronic haemolytic anaemia and severe infections. The underlying phenomenon which causes this disease is the point mutation in the haemoglobin beta gene (Hbβ) found on chromosome 11 p. Increased oxidative stress leads to DNA damage. DNA damage occurring in such conditions can be studied by the buccal micronucleus cytome assay, which is a minimally invasive method for studying chromosomal instability, cell death and regenerative potential of human buccal tissue. Aim To evaluate genomic instability in patients with sickle cell disease by buccal micronucleus cytome assay. Materials and Methods The study included 40 sickle cell anemia patients (Group A) and 40 age and sex matched controls (Group B). Buccal swabs were collected and stained with Papanicolaou (PAP). Number of cells with micronucleus, binuclei, nuclear bud, pyknosis and karyolysis were counted in two groups as parameters for the evaluation of genome stability. Results All the analysis was done using t-test. A p-value of <0.001 was considered statistically significant. There was a statistically significant increase in micronuclei number in SCA patients when compared with controls. Karyolytic (un-nucleated) cell number in Group A was more than to those of the controls. Conclusion The results might suggest that patients with sickle cell anaemia have genome instability which is represented by the presence of micronuclei in the somatic cells. Presence of apoptotic cells might only indicate the bodily damage to the tissue as a result of the disease. PMID:27504413

  17. ECVAM retrospective validation of in vitro micronucleus test (MNT).

    PubMed

    Corvi, Raffaella; Albertini, Silvio; Hartung, Thomas; Hoffmann, Sebastian; Maurici, Daniela; Pfuhler, Stefan; van Benthem, Jan; Vanparys, Philippe

    2008-07-01

    In the past decade several studies comparing the in vitro chromosome aberration test (CAT) and the in vitro micronucleus test (MNT) were performed. A high correlation was observed in each of the studies (>85%); however, no formal validation for the micronucleus in vitro assay had been carried out. Therefore, a working group was established by the European Centre for the Validation of Alternative Methods (ECVAM) to perform a retrospective validation of the existing data, in order to evaluate the validity of the in vitro MNT on the basis of the modular validation approach. The primary focus of this retrospective validation was on the evaluation of the potential of the in vitro MNT as alternative to the standard in vitro CAT. The working group evaluated, in a first step, the available published data and came to the conclusion that two studies [German ring trial, von der Hude, W., Kalweit, S., Engelhardt, G. et al. (2000) In-vitro micronucleus assay with Chinese hamster V79 cells: results of a collaborative study with 26 chemicals. Mutat. Res., 468, 137-163, and SFTG International Collaborative Study, Lorge, E., Thybaud, V., Aardema, M., Oliver, J., Wataka, A., Lorenzon, G. and Marzin, D. (2006) SFTG International Collaborative Study on in-vitro micronucleus test I. General conditions and overall conclusions of the study. Mutat. Res., 607, 13-36] met the criteria for a retrospective validation according to the criteria previously defined by the working group. These two studies were evaluated in depth (including the reanalysis of raw data) and provided the information required for assessing the reliability (reproducibility) of the test. For the assessment of the concordance between the in vitro MNT and the in vitro CAT, additional published data were considered. Based on this retrospective validation, the ECVAM Validation Management Team concluded that the in vitro MNT is reliable and relevant and can therefore be used as an alternative method to the in vitro CAT

  18. Repeated-dose liver micronucleus assay: an investigation with 2-nitropropane, a hepatocarcinogen.

    PubMed

    Kawakami, Satoru; Araki, Tetsuro; Nakajima, Mikio; Kusuoka, Osamu; Uchida, Keisuke; Sato, Norihiro; Tanabe, Yoko; Takahashi, Kaori; Wako, Yumi; Kawasako, Kazufumi; Tsurui, Kazuyuki

    2015-03-01

    The utility of the repeated-dose liver micronucleus (RDLMN) assay in the detection of a genotoxic hepatocarcinogen was evaluated. In this paper, a rat hepatocarcinogen, 2-nitropropane (2-NP), was administered orally to young adult rats for 14 and 28 days without a partial hepatectomy or a mitogen, and the micronucleus induction in liver was examined using a simple method to isolate hepatocytes. In addition, a bone marrow micronucleus assay was conducted concomitantly. The frequency of micronucleated hepatocytes induced by 2-NP increased significantly in both the 14- and 28-day repeated-dose studies, while the bone marrow micronucleus assays were negative in each study. These results indicate that the RDLMN assay is useful for detecting a genotoxic hepatocarcinogen that is negative in bone marrow micronucleus assays and is a suitable in vivo genotoxicity test method for integration into a repeated-dose general toxicity study.

  19. Successful micronucleus testing with the EPI/001 3D reconstructed epidermis model: preliminary findings.

    PubMed

    Andres, E; Molinari, J; Remoué, N; Sá-Rocha, V M; Barrichello, C; Hurtado, S P

    2012-03-18

    Currently, the cosmetics industry relies on the results of in vitro genotoxicity tests to assess the safety of chemicals. Although the cytokinesis-block micronucleus (CBMN) test for the detection of cells that have divided once is routinely used and currently accepted by regulatory agencies, it has some limitations. Reconstituted human epidermis (RHE) is widely used in safety assessments because its physiological properties resemble those of the skin, and because it allows testing of substances such as hydrophobic compounds. Thus, the micronucleus test is being adapted for application in RHE-reconstructed tissues. Here we investigated whether two different reconstructed epidermis models (EPI/001 from Straticell, and RHE/S/17 from Skinethic) are suitable for application of the micronucleus test. We found that acetone does not modify micronucleus frequency, cell viability, and model structure, compared with non-treated RHE. Treatment of the EPI/001 model with mitomycin C and vinblastine resulted in a dose-dependent increase of micronucleus frequency as well as a decrease of tissue viability and of binucleated cell rate, while no changes of the epidermal structure were observed. The number of binucleated cells obtained with the RHE/S/17 model was too small to permit micronucleus testing. These results indicate that the proliferative rate of the tissue used is a critical parameter in performing the micronucleus test on a 3D model.

  20. [Bacterial reverse mutation test and micronucleus test of fucoxanthin oil from microalgae].

    PubMed

    Iio, Kumiko; Okada, Yumika; Ishikura, Masaharu

    2011-01-01

    Fucoxanthin-containing oil extracted from microalga, Chaetoseros sp., was subjected to genotoxicity studies, the bacterial reverse mutation test and the micronucleus test in mice. The number of revertant colonies in fucoxanthin oil-treated plates of all strains tested was less than twice the number of colonies in the negative control, regardless of the presence of the metabolic activator in the bacterial reverse mutation test. In the micronucleus test, 500, 1,000, 2,000 mg/kg body weight of fucoxanthin oil was administered orally to mice. There was no significant increase in micronucleus frequency in bone marrow cells. These results suggest that fucoxanthin oil does not exhibit genotoxicity.

  1. Micronucleus as biomarker of genotoxicity in birds from Brazilian Cerrado.

    PubMed

    Baesse, Camilla Queiroz; Tolentino, Vitor Carneiro de Magalhães; da Silva, Adriano Marcos; Silva, Arthur de Andrade; Ferreira, Giancarlo Ângelo; Paniago, Luís Pedro Mendes; Nepomuceno, Júlio César; de Melo, Celine

    2015-05-01

    Birds are considered efficient bioindicators, by their behavioral characteristics, diversified diet, and use of several vegetation layers, including in contaminated environments. The accumulation of contaminants can harm the reproductive process and survival of species, in addition to causing severe metabolic disorders. Air pollution can also affect the birds' health. Micronucleus analysis, a technique able to evaluate the organisms' sensitivity to contaminant agents, has been regarded as a practical tool for evaluating and monitoring the clastogenic and aneugenic effects caused by pollutants. The purpose of this study was to evaluate the presence of micronuclei in bird species that use forest environments and their surroundings; and to verify if the frequency and amount of micronuclei varies between species, areas and populations. Birds transiting between the Brazilian Cerrado forest and open formations were analyzed, coming from four forest fragments of Triângulo Mineiro, two close to urban areas and two more distant. Birds were captured with mist-nets for collecting blood extensions, which were used for counting micronuclei. In total, 103 individuals of 21 species were captured, and the micronucleus rate for every 5000 erythrocytes analyzed was 1.30. Only six populations had sampling sufficiency. There was no difference between the number of individuals with and without micronuclei (χ²=3.18, df=1, p=0.08). In areas closer to the urban perimeter, the micronuclei averages in birds were greater compared to the most isolated areas (H=27.534, df=3, p<0,001). In São José, the individuals of Myiothlypis flaveola presented a number of micronuclei significantly greater than the Galheiro and Água Fria (H=9.601, df=2, p=0.008). M. flaveola clearly reflected the area quality. The micronuclei analysis in birds was effective for evaluating the area quality as well as the intensity with which the birds respond to impacts caused by the surrounding matrix.

  2. Assessment of methyl methacrylate genotoxicity by the micronucleus test.

    PubMed

    Araújo, Amarildo Mariano de; Alves, Guilherme Rodrigues; Avanço, Guilherme Trevisan; Parizi, José Luiz Santos; Nai, Gisele Alborghetti

    2013-01-01

    The aim of this study was to evaluate the genotoxic potential of methyl methacrylate (MMA) vapor by simulating standard occupational exposure of 8 hours per day and using the micronucleus test. We used 32 adult male Wistar rats divided into three groups: A - 16 rats exposed to MMA for 8 hours a day, B - Eight rats receiving single subcutaneous doses of cyclophosphamide on the first day of the experiment (positive control), C - Eight rats receiving only water and food ad libitum (negative control). Eight rats from group A and all of the rats from groups B and C were sacrificed 24 hours after beginning the experiment (acute exposure in group A). The remaining animals in group A were sacrificed 5 days after the experiment began (repeated exposure assessment in group A, simulating occupational exposure 40 hours/week). Femoral bone marrow was collected from each rat at the time of sacrifice for use in the micronucleus test. Two slides were completed per animal and were stained with Giemsa staining. Two thousand polychromatic erythrocytes were counted per animal. The Kruskal-Wallis test followed by a multiple comparisons test (Dunn test) was used for statistical analysis. The median number of micronuclei was 7.00 in the group exposed to MMA for 1 day, 2.00 in the group exposed to MMA for 5 days, 9.00 in the group exposed to cyclophosphamide (positive control) and 0.756 in the negative control group (p < 0.0001). MMA was genotoxic when measured after 1 day of exposure but was not evidently genotoxic after 5 days.

  3. In vivo assessment of DNA damage and protective effects of extracts from Miconia species using the comet assay and micronucleus test.

    PubMed

    Serpeloni, Juliana Mara; Bisarro dos Reis, Mariana; Rodrigues, Juliana; Campaner dos Santos, Lourdes; Vilegas, Wagner; Varanda, Eliana A; Dokkedal, Anne L; Cólus, Ilce Mara S

    2008-11-01

    The genus Miconia comprises approximately 1000 species belonging to the Melastomataceae family. Several crude plant extracts from Miconia and their isolated compounds have shown biological activities, such as analgesic and anti-neoplastic action; however, no studies concerning their effects on DNA are available. The present study aimed to evaluate, in vivo, the genotoxic and mutagenic effects of four species of plants from Miconia genus using the comet assay and micronucleus test. Their possible protective effects were also evaluated in experiments associating the plant extracts with cyclophosphamide (CPA). The methanolic extracts of Miconia albicans, Miconia cabucu, Miconia rubiginosa, Miconia stenostachya and the chloroformic extract of M. albicans were investigated. For genotoxic and mutagenic evaluations, three concentrations were tested, 200, 400 and 540 mg/kg body weight (bw), based on the solubility limit of the extract in distilled water. For the protective effects, only the highest dose was evaluated against 40 mg/kg bw of CPA. Blood was removed from mice tails pre- (T0) and post-treatment (T1-30 h) for the micronucleus test and 24 h post-treatment for the comet assay. The Student's t-test was used to compare data obtained at T0 and T1, the analysis of variance-Tukey test was used to compare between groups in the micronucleus test and the Kruskal-Wallis and Dunn's test were used to compare different groups in the comet assay. All the extracts induced alterations in DNA migration (comet assay); however, no mutagenic effect was observed in the micronucleus assay. All extracts showed a protective effect against CPA in both assays. Our study showed that the use of crude extracts could be more advantageous than the use of isolated compounds. The interaction between phytochemicals in the extracts showed efficacy in reducing mutagenicity and improving the protective effects.

  4. Cytogenetic biomonitoring in petrol station attendants: A micronucleus study

    PubMed Central

    Singaraju, Medhini; Singaraju, Sasidhar; Parwani, RN; Wanjari, SP

    2012-01-01

    Background: Benzene, which is a major organic product, on chronic exposure can result in many malignant disorders, and therefore exposure to gasoline vapors is classified by the International Agency for Research of Cancer as possible carcinogenic to humans. Petrol station attendants are chronically exposed to petroleum derivatives through inhalation of petrol during vehicle refuelling. Aim: This study is aimed to investigate cytogenotoxic damage in exfoliated buccal cells obtained from petrol station workers and control subjects using micronucleus (MN) test. Materials and Methods: This study was carried out on 30 petrol station attendants working at different petrol stations located in Indore. The control group consisted of 30 healthy subjects who were not exposed to benzene. Buccal cell samples were collected at the end of the work shift. Slides were stained and were evaluated to determine the MN frequencies. Exposure monitoring was performed by the detection of phenol excreted in the urine. Urinary phenol measurements were performed following the colorimetric quantitative determination method of Yamaguchi and Hayashi. Results: Variations in MN frequencies were seen in control and petrol bunk attendants. Conclusion: The MN test in exfoliated epithelial cells seems to be a useful biomarker of occupational exposure to genotoxic chemicals. Phenol is the principal metabolite of benzene. Therefore, phenol concentration in the urine of exposed workers can be used as a biomarker of external exposure. PMID:22438608

  5. Mutagenic activity of isoxazolylnaphthoquinoneimines assayed by micronucleus bone marrow test.

    PubMed

    Sicardi, S M; Ferrato, E

    1995-05-01

    Studies were undertaken to evaluate the ability of various quinoneimines to induce micronuclei in bone marrow cells as a measure of their genotoxicity. Accordingly, 2-hydroxy-N-(3,4-dimethyl-5-isoxazolyl)-1,4-naphthoquinone-4-imine (I), its 2-acetyl derivative (II) and 2-[(5-methyl-3-isoxazolyl)amino]-N-(5-methyl-3-isoxazolyl)-1 ,4- naphthoquinone-4-imine (III), as well as two of their precursors, 2-hydroxynaphthoquinone (NQ-2-OH) and 3,4-dimethyl-5-aminoisoxazole (DMAI) were given by intraperitoneal injection at 5, 50, 100 and 200 mg/Kg doses to S.J.L. Swiss mice with 24 h sampling time. Compounds I and II displayed highly significant differences at 50, 100 and 200 mg/kg doses (p < 0.01) and their mutagenic dose response curves correlated closely with an inverted U-shaped form whose interpretation is still the subject of controversy. NQ-2-OH only produced a significant increase in micronucleus frequency at 50 mg/kg, whereas no mutagenic activity was found for compound III and DMAI at the doses assayed. At 50 mg/kg the order of relative mutagenic potencies was I > II > NQ-2-OH. Mechanisms advanced to explain loss of drug activity at high doses include capture saturation, enzymatic induction during metabolism and participation of an independent defense system.

  6. Assessment of cytotoxic and genotoxic potential of pyracarbolid by Allium test and micronucleus assay.

    PubMed

    Özkara, Arzu; Akyıl, Dilek; Eren, Yasin; Erdoğmuş, S Feyza; Konuk, Muhsin; Sağlam, Esra

    2015-01-01

    The present study evaluates the cytotoxic and genotoxic potential of pyracarbolid using both micronuleus (MN) assay, in human lymphocytes, and Allium cepa assay, in the root meristem cells. In Allium test, EC50 value was determined in order to selecting the test concentrations for the assay and the root tips were treated with 25 ppm (EC50/2), 50 ppm (EC50) and 100 ppm (EC50 × 2) concentrations of pyracarbolid. One percent of dimethyl sulphoxide (DMSO) and methyl methane sulfonate (MMS) were used as negative and positive controls, respectively. In the micronucleus assay, the cultures were treated with four concentrations (250, 500, 750 and 1000 µg/ml) of pyracarbolid for 24 and 48 h, negative and positive controls were also used in the experiment parallely. The results showed that mitotic index (MI) significantly reduced with increasing the pyracarbolid concentration at each exposure time. It was also obtained that prophase and metaphase index decreased significantly in all concentration at each exposure time. Anaphase index decreased as well and results were found to be statistically significant, except 24 h. A significant increase was observed in MN frequency in all concentrations and both treatment periods when compared with the controls. Pyracarbolid also caused a significant reduction in the cytokinesis block proliferation index (CBPI) in all concentration and both exposure time.

  7. Impact of cell cycle delay on micronucleus frequency in TK6 cells.

    PubMed

    Sobol, Zhanna; Spellman, Richard A; Thiffeault, Catherine; Dobo, Krista L; Schuler, Maik

    2014-01-01

    Previous studies with TK6 cells have shown that extending the recovery period after pulse treatment allows for greater micronucleus expression for some compounds. This study explores the role of cell cycle delay in micronucleus expression after pulse treatment with three model genotoxins [mitomycin C, etoposide (ETOP), vinblastine]. Cells were treated for 4 hr and allowed to recover for 36 hr with samples removed at various time points during the recovery period and analyzed for cell cycle distribution, apoptosis and micronucleus frequency. Our results show that mitomycin C causes cell cycle delay for 20 hr after pulse treatment and cell cycle perturbation is no longer evident after 36 hr of recovery. The micronucleus frequency of cells sampled at 36 hr is doubled when compared with cells sampled at 20 hr after mitomycin C removal. When cells were treated with indirect acting genotoxins (ETOP, vinblastine), cell cycle perturbation was not observed at the 20 hr time point. Micronucleus frequency after treatment with either ETOP or vinblastine did not differ between the 20 hr and the 36 hr time point. All three compounds induced similar levels of apoptosis ranging from 4.5 to 5.6% with maximum induction occurring at the 36-hr time point. We conclude that TK6 cells exhibit extended cell cycle arrest after exposure to MMC and can go on to express micronuclei, after overcoming cell cycle arrest.

  8. Relationship between radiation induced dicentric chromosome aberrations and micronucleus formation in human lymphocytes.

    PubMed

    Hatayoglu, S E; Orta, T

    2007-06-01

    Chromosome damage measured by the chromosome aberration technique is a reliable method to assess the radiation dose absorbed by cells. However, this technique has some disadvantages. Scoring is difficult and requires skill and experience which of these lead low number of cell counts. The micronucleus (MN) technique which also measures chromosome losses has easy scoring criteria leading high numbers of cell counts and therefore holds more statistical power. In this study, the relationship between the results of the micronucleus technique and those obtained by the chromosome aberration technique was investigated after radiation doses of 1Gy, 2Gy, 3Gy and 4Gy to peripheral blood lymphocytes of 3 healthy individuals. Increases in the chromosome damage after radiation were observed in both techniques. When the dicentric aberration frequencies that were measured in the chromosome aberration technique and the micronucleus frequencies were compared, no difference (p > 0.05) between these two independent measures of radiation damage was reported. The relationship between the micronuclei and the free acentric chromosome aberrations measured in the chromosome aberration technique was not significant as well as that between the dicentrics and micronuclei. On the basis of the relationship between the dicentric aberrations and the micronucleus frequencies, the micronucleus technique with an easy and short-term application and with an easy scoring can be used as an alternative to the chromosome aberration technique.

  9. Giemsa versus acridine orange staining in the fish micronucleus assay and validation for use in water quality monitoring.

    PubMed

    Polard, T; Jean, S; Merlina, G; Laplanche, C; Pinelli, E; Gauthier, L

    2011-01-01

    This study concerns a comparative analysis of the acridine orange and Giemsa staining procedures for the fish erythrocyte micronucleus assay. The goal was to optimize the assay in the context of field water monitoring. Fish (Carassius carassius) were exposed to a reference genotoxic agent, cyclophosphamide monohydrate 5 mg l(-1) for 2, 4, and 6 days before testing. Slides from each individual were scored using the two procedures. The results show that the assay was more sensitive when acridine orange was used. When slides were Giemsa stained, the presence of ambiguous artefacts, leading to false positives and increasing random variance, reduced the contrast between exposed and control samples. Acridine Orange staining was then applied in the context of water quality monitoring. Fish were exposed for 4 days to water sampled in two hydrological contexts: basal flow and spring flood. The results show that exposure to spring flood water in an agricultural stream can induce mutagenicity.

  10. Cytotoxicity of diesel engine exhaust among the Chinese occupational population: a complement of cytokinesis-block micronucleus cytome.

    PubMed

    Zhang, Xiao; Xiao, Xinhua; Duan, Huawei; Gao, Feng; Li, Yuanyuan; Niu, Yong; Gao, Weimin; Wang, Haisheng; Yu, Shanfa; Zheng, Yuxin

    2016-01-01

    Diesel engine exhaust (DEE), a ubiquitous environmental pollutant, has been associated with adverse health effects. Revelation of cellular and molecular changes is critical for understanding environmental exposure-related diseases. Although the molecular-level effects of DEE exposure have been investigated, whether it is associated with aberrant changes at cellular level is largely unknown at the population level. In the present study, we measured urinary concentrations of 6 mono-hydroxylated PAHs (OH-PAHs) and cytotoxicity-related endpoints including apoptosis and necrosis frequencies, and nuclear division cytotoxicity index (NDCI) in peripheral blood lymphocytes (PBLs) of 79 DEE-exposed workers and 59 non-DEE-exposed workers. We found that DEE-exposed workers had significantly higher necrosis frequency and lower NDCI than did non-DEE-exposed workers (both p < 0.001). In all study subjects and nonsmoking workers, urinary summed OH-PAHs was associated with increased necrosis frequency and reduced NDCI. In nonsmoking workers, an interquartile range increase in urinary summed OH-PAHs was associated with 105.03% increase in necrosis frequency and 8.70% decrease in NDCI. Taking advantage of the previous measure of micronucleus frequency, we observed that micronucleus frequency was positively correlated with apoptosis and necrosis frequencies (r = 0.277, p = 0.047 and r = 0.452, p = 0.001, respectively) and negatively correlated with NDCI (r = -0.477, p < 0.001). In conclusion, our results suggested that DEE exposure was associated with increased necrosis frequency and further with reduced NDCI in PBLs, providing evidence of DEE exposure-induced cytotoxicity in humans.

  11. [Micronucleus test of human oral buccal epithelium: problems, progress and prospects].

    PubMed

    Kalaev, V N; Artiukhov, V G; Nechaeva, M S

    2014-01-01

    The articles by russian and foreign authors for the period from 2000 to 2012, devoted to the problems of application, analysis and interpretation of the results of micronucleus test in human buccal epithelium has been analyzed in the review. Nuclear abnormality founding in the cells of the oral mucosa has been described. The paper summarizes works devoted to the analysis of the influence of the micronucleus test methods (painting, taking scrapings) to its results. Modern opinions about the factors of different etiology (sex, age, genotype, psycho-physiological characteristics, immune status, diseases of different etiology, man-made pollution, climatic and geographical conditions, ionizing and nonionizing radiation, chemical compounds (drugs, dietary supplements, androgenic steroids, etc.), dental fillings, occupational exposures, alcohol, using tobacco blends) inducing the estimation of nuclear aberration has been summarized as a scheme. The problems and unresolved issues related to the peculiarities of micronucleus test has been noted.

  12. Tradescantia-micronucleus (Trad-MCN) bioassay on clastogenicity of wastewater and in situ monitoring.

    PubMed

    Ruiz, E F; Rabago, V M; Lecona, S U; Perez, A B; Ma, T H

    1992-11-01

    The Tradescantia-micronucleus (Trad-MCN) bioassay was used to determine the clastogenicity of wastewater samples collected from the Arena canal which contains effluent from the industrial district Benito Juarez of the city of Queretaro, Mexico. Fifteen wastewater samples which were collected, in most cases, at bi-weekly intervals beginning in September 1986 through February 1988, after a 3-fold dilution were used to treat Tradescantia plant cuttings. The clastogenicity expressed in terms of micronucleus frequencies of treated groups (30 h of treatment without recovery time) was significantly (0.01) higher than that of the tapwater control groups. The Trad-MCN bioassay was also used for in situ monitoring of air pollutants for the clastogenicity at 3 sites near the industrial and residential areas (Flores Magon, Conalep and Bellas Artes) of the city of Queretaro. Fourteen monitoring trips were made to each of the 3 sites at monthly intervals beginning in May 1988 through June 1990. Seasonal variation of micronucleus frequencies was exhibited with the peak clastogenicities shown in May and June 1988, June 1989 and April 1990 at the three sites. Micronucleus frequencies of all the exposed groups at the Conalep site, a predominantly industrial area, were markedly higher than that of the laboratory control groups throughout the 2-year period.

  13. A Genome-Wide Association Study for Regulators of Micronucleus Formation in Mice

    PubMed Central

    McIntyre, Rebecca E.; Nicod, Jérôme; Robles-Espinoza, Carla Daniela; Maciejowski, John; Cai, Na; Hill, Jennifer; Verstraten, Ruth; Iyer, Vivek; Rust, Alistair G.; Balmus, Gabriel; Mott, Richard; Flint, Jonathan; Adams, David J.

    2016-01-01

    In mammals the regulation of genomic instability plays a key role in tumor suppression and also controls genome plasticity, which is important for recombination during the processes of immunity and meiosis. Most studies to identify regulators of genomic instability have been performed in cells in culture or in systems that report on gross rearrangements of the genome, yet subtle differences in the level of genomic instability can contribute to whole organism phenotypes such as tumor predisposition. Here we performed a genome-wide association study in a population of 1379 outbred Crl:CFW(SW)-US_P08 mice to dissect the genetic landscape of micronucleus formation, a biomarker of chromosomal breaks, whole chromosome loss, and extranuclear DNA. Variation in micronucleus levels is a complex trait with a genome-wide heritability of 53.1%. We identify seven loci influencing micronucleus formation (false discovery rate <5%), and define candidate genes at each locus. Intriguingly at several loci we find evidence for sexual dimorphism in micronucleus formation, with a locus on chromosome 11 being specific to males. PMID:27233670

  14. A Genome-Wide Association Study for Regulators of Micronucleus Formation in Mice.

    PubMed

    McIntyre, Rebecca E; Nicod, Jérôme; Robles-Espinoza, Carla Daniela; Maciejowski, John; Cai, Na; Hill, Jennifer; Verstraten, Ruth; Iyer, Vivek; Rust, Alistair G; Balmus, Gabriel; Mott, Richard; Flint, Jonathan; Adams, David J

    2016-08-09

    In mammals the regulation of genomic instability plays a key role in tumor suppression and also controls genome plasticity, which is important for recombination during the processes of immunity and meiosis. Most studies to identify regulators of genomic instability have been performed in cells in culture or in systems that report on gross rearrangements of the genome, yet subtle differences in the level of genomic instability can contribute to whole organism phenotypes such as tumor predisposition. Here we performed a genome-wide association study in a population of 1379 outbred Crl:CFW(SW)-US_P08 mice to dissect the genetic landscape of micronucleus formation, a biomarker of chromosomal breaks, whole chromosome loss, and extranuclear DNA. Variation in micronucleus levels is a complex trait with a genome-wide heritability of 53.1%. We identify seven loci influencing micronucleus formation (false discovery rate <5%), and define candidate genes at each locus. Intriguingly at several loci we find evidence for sexual dimorphism in micronucleus formation, with a locus on chromosome 11 being specific to males.

  15. DIETARY FOLATE DEFICIENCY ENHANCES ARSENIC-INDUCED MICRONUCLEUS FORMATION IN MICE

    EPA Science Inventory


    Dietary folate deficiency enhances arsenic-induced micronucleus formation in mice.

    Folate deficiency increases background levels ofDNA damage and can enhance the mutagenicity of chemical agents. Duplicate experiments were performed to investigate the effect of dietary...

  16. 40 CFR 798.5395 - In vivo mammalian bone marrow cytogenetics tests: Micronucleus assay.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... micronucleus in the cytoplasm. The visualization of micronuclei is facilitated in these cells because they lack... frequency of micronucleated polychromatic erythrocytes in bone marrow of treated animals. (b) Definition... lag behind at anaphase of cell division. After telophase, these fragments may not be included in...

  17. 40 CFR 798.5395 - In vivo mammalian bone marrow cytogenetics tests: Micronucleus assay.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... micronucleus in the cytoplasm. The visualization of micronuclei is facilitated in these cells because they lack... frequency of micronucleated polychromatic erythrocytes in bone marrow of treated animals. (b) Definition... lag behind at anaphase of cell division. After telophase, these fragments may not be included in...

  18. 40 CFR 798.5395 - In vivo mammalian bone marrow cytogenetics tests: Micronucleus assay.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... micronucleus in the cytoplasm. The visualization of micronuclei is facilitated in these cells because they lack... frequency of micronucleated polychromatic erythrocytes in bone marrow of treated animals. (b) Definition... lag behind at anaphase of cell division. After telophase, these fragments may not be included in...

  19. 40 CFR 798.5395 - In vivo mammalian bone marrow cytogenetics tests: Micronucleus assay.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... micronucleus in the cytoplasm. The visualization of micronuclei is facilitated in these cells because they lack... frequency of micronucleated polychromatic erythrocytes in bone marrow of treated animals. (b) Definition... lag behind at anaphase of cell division. After telophase, these fragments may not be included in...

  20. Association between micronucleus frequency and cervical intraepithelial neoplasia grade in Thinprep cytological test and its significance.

    PubMed

    Shi, Yong-Hua; Wang, Bo-Wei; Tuokan, Talaf; Li, Qiao-Zhi; Zhang, Ya-Jing

    2015-01-01

    A micronucleus is an additional small nucleus formed due to chromosomes or chromosomal fragments fail to be incorporated into the nucleus during cell division. In this study, we assessed the utility of micronucleus counting as a screening tool in cervical precancerous lesions in Thinprep cytological test smears under oil immersion. High risk HPV was also detected by hybrid capture-2 in Thinprep cytological test smears. Our results showed that micronucleus counting was significantly higher in high-grade squamous intraepithelial lesion (HSIL) and invasive carcinoma cases compared to low-grade squamous intraepithelial lesion (LSIL) and non-neoplastic cases. Receiver operating characteristic (ROC) curve analysis revealed that micronucleus counting possessed a high degree of sensitivity and specificity for identifying HSIL and invasive carcinoma. Cut-off of 7.5 for MN counting gave a sensitivity of 89.6% and a specificity of 66.7% (P = 0.024 and AUC = 0.892) for detecting HSIL and invasive carcinoma lesions. Multiple linear regression analysis showed that only HSIL and invasive cancer lesions not age, duration of marital life and number of pregnancy are significantly associated with MN counting. The positive rate of high risk HPV was distinctly higher in LSIL, HSIL and invasive cancer than that in non-neoplstic categories. In conclusions, MN evaluation may be viewed as an effective biomarker for cervical cancer screening. The combination of MN count with HPV DNA detection and TCT may serve as an effective means to screen precancerous cervical lesions in most developing nations.

  1. Micronucleus test on Triturus carnifex as a tool for environmental biomonitoring.

    PubMed

    Udroiu, I; Sgura, A; Vignoli, L; Bologna, M A; D'Amen, M; Salvi, D; Ruzza, A; Antoccia, A; Tanzarella, C

    2015-05-01

    The amphibian micronucleus test has been widely used during the last 30 years to test the genotoxic properties of several chemicals and as a tool for ecogenotoxic monitoring. The vast majority of these studies were performed on peripheral blood of urodelan larvae and anuran tadpoles and to a lesser extent adults were also used. In this study, we developed protocols for measuring micronuclei in adult shed skin cells and larval gill cells of the Italian crested newt (Triturus carnifex). Amphibians were collected from ponds in two protected areas in Italy that differed in their radon content. Twenty-three adult newts and 31 larvae were captured from the radon-rich pond, while 20 adults and 27 larvae were taken from the radon-free site. The animals were brought to the laboratory and the micronucleus test was performed on peripheral blood and shed skins taken from the adults and on larval gills. Samples from the radon-rich site showed micronucleus frequencies higher than those from the radon-free site and the difference was statistically significant in gill cells (P < 0.00001). Moreover, the larval gills seem to be more sensitive than the adult tissues. This method represents an easy (and noninvasive in the case of the shed skin) application of the micronucleus assay that can be useful for environmental studies in situ.

  2. Activity of the human carcinogen MeCCNU in the mouse bone marrow micronucleus assay

    SciTech Connect

    Tinwell, H.; Ashby, J. )

    1991-01-01

    The nitrosourea mustard MeCCNU is the most recent organic chemical to be classified as a human carcinogen by IARC. MeCCNU gave a strong positive response when tested in the mouse bone marrow micronucleus assay. Activity was evident using either ip injection or oral gavage of the test chemical. These results further support the correlation between human carcinogens and their genotoxicity.

  3. Absence of micronucleus formation in CHO-K1 cells cultivated in platelet lysate enriched medium.

    PubMed

    Bernardi, Martina; Adami, Valentina; Albiero, Elena; Madeo, Domenico; Rodeghiero, Francesco; Astori, Giuseppe

    2014-03-01

    Human platelet lysate (PL) represents an effective substitute of fetal bovine serum (FBS) for mesenchymal stromal cell (MSC) cultivation. Compared to FBS, PL favors MSC proliferation significantly shortening the population doubling time and avoiding the risks related to the use of animal derivatives. Growth factors contained in the platelets are released upon platelet disruption following freezing/thawing cycles or as we have recently described by using ultrasound. We have investigated whether the increased cell proliferation achieved by using PL could induce mitotic stress and whether the potential formation of free radicals during PL production by ultrasound could cause chromosomal instability in mammalian cells. We have applied an image analysis assisted high content screening (HCS) in vitro micronucleus assay in the Chinese Hamster Ovarian K1 (CHO-K1) rodent mammalian cell line. PL was produced by sonication; for the micronucleus assay, CHO-K1 cells were exposed to increasing concentrations of PL. Cytokinesis was blocked by cytochalasin B, nuclei were stained with bisbenzimide and images were acquired and analyzed automatically using an HCS system, both with a 20× and a 10× objective. Our results suggest that growth stimulus induced by the use of PL did not significantly increase micronucleus formation in CHO-K1 cells compared to negative control. Micronucleus testing in conjunction with HCS could represent a valid tool to evaluate the safety of ancillary materials used in the production of cell-based medicinal products.

  4. Automatic analysis of the micronucleus test in primary human lymphocytes using image analysis.

    PubMed

    Frieauff, W; Martus, H J; Suter, W; Elhajouji, A

    2013-01-01

    The in vitro micronucleus test (MNT) is a well-established test for early screening of new chemical entities in industrial toxicology. For assessing the clastogenic or aneugenic potential of a test compound, micronucleus induction in cells has been shown repeatedly to be a sensitive and a specific parameter. Various automated systems to replace the tedious and time-consuming visual slide analysis procedure as well as flow cytometric approaches have been discussed. The ROBIAS (Robotic Image Analysis System) for both automatic cytotoxicity assessment and micronucleus detection in human lymphocytes was developed at Novartis where the assay has been used to validate positive results obtained in the MNT in TK6 cells, which serves as the primary screening system for genotoxicity profiling in early drug development. In addition, the in vitro MNT has become an accepted alternative to support clinical studies and will be used for regulatory purposes as well. The comparison of visual with automatic analysis results showed a high degree of concordance for 25 independent experiments conducted for the profiling of 12 compounds. For concentration series of cyclophosphamide and carbendazim, a very good correlation between automatic and visual analysis by two examiners could be established, both for the relative division index used as cytotoxicity parameter, as well as for micronuclei scoring in mono- and binucleated cells. Generally, false-positive micronucleus decisions could be controlled by fast and simple relocation of the automatically detected patterns. The possibility to analyse 24 slides within 65h by automatic analysis over the weekend and the high reproducibility of the results make automatic image processing a powerful tool for the micronucleus analysis in primary human lymphocytes. The automated slide analysis for the MNT in human lymphocytes complements the portfolio of image analysis applications on ROBIAS which is supporting various assays at Novartis.

  5. Factors affecting the in vitro micronucleus assay for evaluation of nanomaterials.

    PubMed

    Li, Yan; Doak, Shareen H; Yan, Jian; Chen, David H; Zhou, Min; Mittelstaedt, Roberta A; Chen, Ying; Li, Chun; Chen, Tao

    2017-01-01

    A number of in vitro methodologies have been used to assess the genotoxicity of different nanomaterials, including titanium dioxide nanoparticles (TiO2 NPs) and silver nanoparticles (AgNPs). The in vitro micronucleus assay is one of the most commonly used test methods for genotoxicity evaluation of nanomaterials. However, due to the novel features of nanomaterials, such as high adsorption capacity and fluorescence properties, there are unexpected interactions with experimental components and detection systems. In this study, we evaluate the interference by two nanoparticles, AgNPs and TiO2 NPs, with the in vitro micronucleus assay system and possible confounding factors affecting cytotoxicity and genotoxicity assessment of the nanomaterials including cell lines with different p53 status, nanoparticle coatings and fluorescence, cytochalasin B, fetal bovine serum in cell treatment medium and different measurement methodologies for detecting micronuclei. Our results showed that micronucleus induction by AgNPs was similar when evaluated using flow cytometry or microscope, whereas the induction by TiO2 NPs was different using the two methods due to TiO2's fluorescence interference with the cytometry equipment. Cells with the mutated p53 gene were more sensitive to micronucleus induction by AgNPs than the p53 wild-type cells. The presence of serum during treatment increased the toxicity of AgNPs. The coatings of nanoparticles played an important role in the genotoxicity of AgNPs. These collective data highlight the importance of considering the unique properties of nanoparticles in assessing their genotoxicity using the in vitro micronucleus assay.

  6. State of the Art High-Throughput Approaches to Genotoxicity: Flow Micronucleus, Ames II, GreenScreen and Comet

    EPA Pesticide Factsheets

    State of the Art High-Throughput Approaches to Genotoxicity: Flow Micronucleus, Ames II, GreenScreen and Comet (Presented by Dr. Marilyn J. Aardema, Chief Scientific Advisor, Toxicology, Dr. Leon Stankowski, et. al. (6/28/2012)

  7. Genetic Toxicity Evaluation of Iodotrifluoromethane (CFsub3I). Volume 2. Results of In Vivo Mouse Bone Marrow Erythrocyte Micronucleus Testing

    DTIC Science & Technology

    1995-01-01

    the mouse micronucleus test which measures the clastogenic (chromosomes breaking) action of chemicals by the induction of micronuclei in bone marrow...preliminary toxicity information obtained by ManTech, a mouse bone marrow micronucleus test of CF 3I was conducted using 2.6, 5.0, and 7.5% CF 3I...the mice sacrificed 24 hours after the third exposure. Erythrocytes from mice exposed to the test material, and to the negative and positive controls

  8. Micronucleus assay in human fibroblasts: a measure of spontaneous chromosomal instability and mutagen hypersensitivity

    SciTech Connect

    Rudd, N.L.; Hoar, D.I.; Greentree, C.L.; Dimnik, L.S.; Hennig, U.S.S.

    1988-01-01

    By comparing fibroblast strains derived from individuals exhibiting chromosome instability and/or mutagen hypersensitivity (Cockayne syndrome, ataxia telangiectasia, and Fanconi anemia) with strains derived from health donors, the fibroblast micronucleus assay has been established as a reproducible measure of the genotypic variation in spontaneous or mitomycin C (MMC)-induced chromosomal instability. The patient strains that were moderately or exquisitely sensitive to MMC could be distinguished readily from the control strains, both in levels of spontaneous micronuclei and in sensitivity to MMC, whereas the mildly sensitive strain (Cockayne syndrome) overlapped with the control range. The reproducibility of the assay was evaluated within and between experiments. In addition to its value as a test system for genotoxins, the fibroblast micronucleus assay may be useful for investigating genetically determined hypersensitivity to mutagens, elevated spontaneous chromosomal breakage, and chromosome segregation errors.

  9. [Application of micronucleus test for the demonstration of antimutagenic properties of natural substances].

    PubMed

    Villani, P; Orsière, T; Bartfai, E; Pélissier, A L; Duffaud, F; Bouvenot, G; Botta, A

    1997-01-01

    Authors have used a reliable and reproductible original model of controlled production of free radicals for the cytokinesis-block micronucleus assay. This mutagenicity test is of easy realization and quick interpretation. An experimental model is proposed to test mutagenic activity of free radical generators and antioxydant properties of many substances, such as ascorbic acid. Its addition to the culture medium showed a significant decrease in the rate of micronucleated cells exposed to the free radical generator. The study of other antioxydant compounds (beta-caroten and 5-hydroxyquinolin) have confirmed results previously obtained with ascorbic acid. Thus, the free radical generator coupled to the cytokinesis-block micronucleus assay represents a reliable test to study and evaluate the antioxydant power of natural substances.

  10. Genotoxicity of Aflatoxin B1 and Ochratoxin A after simultaneous application of the in vivo micronucleus and comet assay.

    PubMed

    Corcuera, Laura-Ana; Vettorazzi, Ariane; Arbillaga, Leire; Pérez, Noemí; Gil, Ana Gloria; Azqueta, Amaya; González-Peñas, Elena; García-Jalón, Jose Antonio; López de Cerain, Adela

    2015-02-01

    Aflatoxin B1 (AFB1) and Ochratoxin A (OTA) are genotoxic mycotoxins that can contaminate a variety of foodstuffs, the liver and the kidney being their target organs, respectively. The micronucleus (MN) assay (bone marrow) and the comet assay (liver and kidney) were performed simultaneously in F344 rats, treated with AFB1 (0.25 mg/kg b.w.), OTA (0.5 mg/kg b.w.) or both mycotoxins. After AFB1 treatment, histopathology and biochemistry analysis showed liver necrosis, focal inflammation and an increase in Alanine Aminotransferase and Aspartate Aminotransferase. OTA alone did not cause any alteration. The acute hepatotoxic effects caused by AFB1 were less pronounced in animals treated with both mycotoxins. With regard to the MN assay, after 24 h, positive results were obtained for AFB1 and negative results were obtained for OTA, although both toxins caused bone marrow toxicity. In the combined treatment, OTA reduced the toxicity and the number of MN produced by AFB1. In the comet assay, after 3 h, positive results were obtained for AFB1 in the liver and for OTA in the kidney. The combined treatment reduced DNA damage in the liver and had no influence in the kidney. Altogether, these results may be indicative of an antagonistic relationship regarding the genotoxicity of both mycotoxins.

  11. Genotoxicity of silver nanoparticles evaluated using the Ames test and in vitro micronucleus assay.

    PubMed

    Li, Yan; Chen, David H; Yan, Jian; Chen, Ying; Mittelstaedt, Roberta A; Zhang, Yongbin; Biris, Alexandru S; Heflich, Robert H; Chen, Tao

    2012-06-14

    Silver nanoparticles (AgNPs) have antimicrobial properties, which have contributed to their widespread use in consumer products. A current issue regarding nanomaterials is the extent to which existing genotoxicity assays are useful for evaluating the risks associated with their use. In this study, the genotoxicity of 5 nm AgNPs was assessed using two standard genotoxicity assays, the Salmonella reverse mutation assay (Ames test) and the in vitro micronucleus assay. Using the preincubation version of the Ames assay, Salmonella strains TA102, TA100, TA1537, TA98, and TA1535 were treated with 0.15-76.8 μg/plate of the AgNPs. Toxicity limited the doses that could be assayed to 2.4-38.4 μg/plate; no increases in mutant frequency over the vehicle control were found for the concentrations that could be assayed. Human lymphoblastoid TK6 cells were treated with 10-30 μg/ml AgNPs, and additional cells were treated with water and 0.73 gy X-rays as vehicle and positive controls. Micronucleus frequency was increased by the AgNP treatment in a dose-dependent manner. At a concentration of 30 μg/ml (with 45.4% relative population doubling), AgNPs induced a significant, 3.17-fold increase with a net increase of 1.60% in micronucleus frequency over the vehicle control, a weak positive response by our criteria. These results demonstrate that the 5 nm AgNP are genotoxic in TK6 cells. Also, the data suggest that the in vitro micronucleus assay may be more appropriate than the Ames test for evaluating the genotoxicity of the AgNPs.

  12. Improvement of Vicia-micronucleus test for assessment of soil quality: a proposal for international standardization.

    PubMed

    Foltête, Anne-Sophie; Dhyèvre, Adrien; Férard, Jean-François; Cotelle, Sylvie

    2011-11-01

    The Viciafaba root tip micronucleus test is one of the most employed plant genotoxicity assays, and has been used on various types of contaminated materials. This test has been standardized by AFNOR, the French member organization of ISO. However, this test is usually performed with a water extraction step but soil genotoxicity assessment would be more relevant when performed directly in the soil itself. In order to harmonize these protocols, an ISO standard for the V.faba micronucleus test in both liquid phase (exposure of plants to different liquid matrix, including soil water extracts) and solid phase (direct exposure of plants to the soil) would be very useful. In this context, we compared two exposure durations in the solid phase (48 h and 5 d) for the V.faba micronucleus test with two different well-known genotoxicants, maleic hydrazide and copper sulfate. We concluded that these two durations induced equivalent sensitivity: the micronucleus frequency was significantly increased with 5 μmol maleic hydrazide per kg dry soil and with 2 mmol copper sulfate per kg dry soil with both exposure durations. However, exposing roots to soil during 48 h is more practical. Moreover, organically and conventionally cultured seeds were employed to determine whether the seed provenance influenced the test sensitivity. Organic seeds were less sensitive to copper, possibly because copper-based treatments are permitted, and often applied, in organic farms. Therefore, in the absence of completely non-treated seeds, organically-cultured seeds did not appear to offer any advantages over conventional seeds.

  13. Histone markers identify the mode of action for compounds positive in the TK6 micronucleus assay.

    PubMed

    Cheung, Jennifer R; Dickinson, Donna A; Moss, Jocelyn; Schuler, Maik J; Spellman, Richard A; Heard, Pamela L

    2015-01-01

    The in vitro micronucleus assay with TK6 cells is frequently used as part of the genotoxicity testing battery for pharmaceuticals. Consequently, follow-up testing strategies are needed for positive compounds to determine their mode of action, which would then allow for deployment of appropriate in vivo follow-up strategies. We have chosen 3 micronucleus positive compounds, the clastogen etoposide, the aneugen noscapine and the cytotoxicant tunicamycin to evaluate different approaches to determine their aneugenic or clastogenic properties. Each of the three compounds were evaluated following 4 and 24h of continuous treatment by flow cytometry for micronucleus induction, the aneugenicity markers phosphorylated-histone 3 (p-H3) and polyploidy, the clastogenicity marker γH2AX and the apoptosis marker cleaved caspase 3. They were further evaluated by Western blot for mono-ubiquitinated and γH2AX. Results show that the clastogen etoposide produced a dose related increase in γH2AX and mono-ubiquitinated H2AX and a dose related decrease in p-H3 positive mitotic cells. Conversely, the aneugen produced increases in p-H3 and polyploidy with no significant increases seen in mono-ubiquitinated H2AX or γH2AX. Lastly, the cytotoxicant tunicamycin induced neither an increase in p-H3 nor γH2AX. All three compounds produced dose-related increases in cleaved caspase 3. The results from this study provide evidence that adding clastogenicity and aneugenicity markers to the in vitro micronucleus assay in TK6 cells could help to identify the mode of action of positive compounds. The combination of endpoints suggested here needs to be further evaluated by a broader set of test compounds.

  14. Micronucleus frequency is increased in peripheral blood lymphocytes of nuclear power plant workers.

    PubMed

    Hadjidekova, Valeria B; Bulanova, Minka; Bonassi, Stefano; Neri, Monica

    2003-12-01

    Nuclear power plant workers are exposed to ionizing radiation at relatively low doses and for prolonged periods of time. To investigate the extent of genetic damage in these workers, a group of 133 nuclear power plant workers and 39 healthy controls were compared using the cytokinesis-block micronucleus assay. The frequency of micronuclei was significantly increased in peripheral lymphocytes of nuclear power plant workers (20.5 +/- 9.7% compared to 13.7 +/- 5.9%). A significant dose-response relationship was observed between micronucleus (MN) frequency and both the accumulated dose and the duration of employment (P < 0.01 for both variables after adjusting for age, gender and cigarette smoking) with an evident leveling off for exposures over 200 mSv. Accumulated dose and duration of employment were significantly correlated but exerted independent effects on MN frequency. For non-occupational parameters, age was significantly associated with the frequency of micronuclei, while gender was not. Smoking habit showed no overall effect, whereas increased chromosome damage was evident in smokers of more than 20 cigarettes per day. In conclusion, a dose-related association between MN frequency and exposure to ionizing radiation was evident in nuclear power plant workers, encouraging the application of the cytokinesis-block micronucleus assay in biomonitoring studies of human populations with prolonged exposure to ionizing radiation.

  15. Health assessment of gasoline and fuel oxygenate vapors: micronucleus and sister chromatid exchange evaluations.

    PubMed

    Schreiner, Ceinwen A; Hoffman, Gary M; Gudi, Ramadevi; Clark, Charles R

    2014-11-01

    Micronucleus and sister chromatid exchange (SCE) tests were performed for vapor condensate of baseline gasoline (BGVC), or gasoline with oxygenates, methyl tert-butyl ether (G/MTBE), ethyl tert butyl ether (G/ETBE), t-amyl methyl ether (G/TAME), diisopropyl ether (G/DIPE), t-butyl alcohol (TBA), or ethanol (G/EtOH). Sprague Dawley rats (the same 5/sex/group for both endpoints) were exposed to 0, 2000, 10,000, or 20,000mg/m(3) of each condensate, 6h/day, 5days/week over 4weeks. Positive controls (5/sex/test) were given cyclophosphamide IP, 24h prior to sacrifice at 5mg/kg (SCE test) and 40mg/kg (micronucleus test). Blood was collected from the abdominal aorta for the SCE test and femurs removed for the micronucleus test. Blood cell cultures were treated with 5μg/ml bromodeoxyuridine (BrdU) for SCE evaluation. No significant increases in micronucleated immature erythrocytes were observed for any test material. Statistically significant increases in SCE were observed in rats given BGVC alone or in female rats given G/MTBE. G/TAME induced increased SCE in both sexes at the highest dose only. Although DNA perturbation was observed for several samples, DNA damage was not expressed as increased micronuclei in bone marrow cells. Inclusion of oxygenates in gasoline did not increase the effects of gasoline alone or produce a cytogenetic hazard.

  16. Dose rate effect of pulsed electron beam on micronucleus frequency in human peripheral blood lymphocytes.

    PubMed

    Acharya, Santhosh; Sanjeev, Ganesh; Bhat, Nagesh N; Narayana, Yerol

    2010-03-01

    The micronucleus assay in human peripheral blood lymphocytes is a sensitive indicator of radiation damage and could serve as a biological dosimeter in evaluating suspected overexposure to ionising radiation. Micronucleus (MN) frequency as a measure of chromosomal damage has also extensively been employed to quantify the effects of radiation dose rate on biological systems. Here we studied the effects of 8 MeV pulsed electron beam emitted by Microtron electron accelerator on MN induction at dose rates between 35 Gy min-1 and 352.5 Gy min-1. These dose rates were achieved by varying the pulse repetition rate (PRR). Fricke dosimeter was employed to measure the absorbed dose at different PRR and to ensure uniform dose distribution of the electron beam. To study the dose rate effect, blood samples were irradiated to an absorbed dose of (4.7+/-0.2) Gy at different rates and cytogenetic damage was quantified using the micronucleus assay. The obtained MN frequency showed no dose rate dependence within the studied dose rate range. Our earlier dose effect study using 8 MeV electrons revealed that the response of MN was linear-quadratic. Therefore, in the event of an accident, dose estimation can be made using linear-quadratic dose response parameters, without adding dose rate as a correction factor.

  17. Environmental exposure to benzene, micronucleus formation and polymorphisms in DNA-repair genes: a pilot study.

    PubMed

    Angelini, Sabrina; Maffei, Francesca; Bermejo, Justo Lorenzo; Ravegnini, Gloria; L'insalata, Domenica; Cantelli-Forti, Giorgio; Violante, Francesco Saverio; Hrelia, Patrizia

    2012-03-18

    This report is part of a biomarker study conducted in an Italian population with exposure to environmental benzene ranging from 1.43 to 31.41 μg/m³ (values from personal sampling). DNA damage induced by benzene is the crucial mechanism of its genotoxicity, which leads to chronic benzene poisoning, haematotoxicity and leukaemia. Therefore, genetic variation in DNA-repair genes may modulate susceptibility to benzene-induced DNA damage. In light of this, the effects of polymorphisms in DNA-repair genes (APEX1, hOGG1, NBS1, XPD, XRCC1, and XRCC3) on micronucleus (MN) formation as a biomarker of early biological effects were evaluated. A significantly higher median MN frequency was recorded in traffic wardens than in controls. However, none of the analysed polymorphisms was significantly associated with the median MN frequency. A gene-gender interaction was observed for the APEX1 genotype. The APEX1 variant genotype was associated with significantly lower median MN frequency in men, not in women. Statistical analysis did not reveal any association between the score of the protective alleles - hypothetically pushing the pathway towards optimal DNA-damage repair - and MN. Even though there are some limitations in the study, our results indicate that the general population may be exposed to benzene concentrations higher than the threshold level for air-quality standards in the European Union of 10 μg/m³. Furthermore, urban traffic wardens are exposed to significantly higher levels of benzene than individuals spending most of the time indoors. This higher exposure may contribute to DNA damage, suggesting that benzene might be implicated both as an environmental and occupational risk factor in leukaemia and other haematological diseases. In conclusion, this study suggest the need for (i) regular monitoring of traffic wardens for possible exposure to benzene, as a precautionary step to reduce the associated health risks, and (ii) more comprehensive studies in order to

  18. Effects of soil pH on the Vicia-micronucleus genotoxicity assay.

    PubMed

    Dhyèvre, Adrien; Foltête, Anne Sophie; Aran, Delphine; Muller, Serge; Cotelle, Sylvie

    2014-11-01

    In the field of contaminated sites and soil management, chemical analyses only bring typological data about pollution. As far as bioavailability and effects on organisms are concerned, we need ecotoxicology tools. In this domain, among many existing tests, we chose to study genotoxicity because it is a short-term endpoint with long-term consequences. The aim of this study is to assess the effects of soil pH on the results of the Vicia faba root tip micronucleus test for the two following reasons: (i) to define the pH range within which the test can be performed without modifying the soil to be tested, within the framework of the ISO standard of the test and (ii) to provides information about the effects of the pH on the genotoxic potential of soils. In this context, we modified the pH of a standard soil with HCl or NaOH and we spiked the matrix with copper (2, 4 and 8 mmol kg(-1) dry soil) or with maleic hydrazide, an antigerminative chemical (5, 10 and 20 μmol kg(-1) dry soil). We concluded that the pH had no effect on the mitotic index or micronucleus frequency in the root cells of the negative controls: extreme pH values did not induce micronucleus formation in root cells. Moreover, according to our results, the Vicia-micronucleus test can be performed with pH values ranging between 3.2 and 9.0, but in the ISO 29200 "Soil quality--assessment of genotoxic effects on higher plants--V. faba micronucleus test" we recommended to use a control soil with a pH value ranging between 5 and 8 for a more accurate assessment of chemical genotoxicity. We also found that acid pH could increase the genotoxic potential of pollutants, especially heavy metals. With hydrazide maleic spiked soil, plants were placed in a situation of double stress, i.e. toxicity caused by extreme pH values and toxicity induced by the pollutant.

  19. Evaluation of a liver micronucleus assay in young rats (III): a study using nine hepatotoxicants by the Collaborative Study Group for the Micronucleus Test (CSGMT)/Japanese Environmental Mutagen Society (JEMS)-Mammalian Mutagenicity Study Group (MMS).

    PubMed

    Takasawa, Hironao; Suzuki, Hiroshi; Ogawa, Izumi; Shimada, Yasushi; Kobayashi, Kazuo; Terashima, Yukari; Matsumoto, Hirotaka; Aruga, Chinami; Oshida, Keiyu; Ohta, Ryo; Imamura, Tadashi; Miyazaki, Atsushi; Kawabata, Masayoshi; Minowa, Shigenori; Hayashi, Makoto

    2010-04-30

    We have been investigating a liver micronucleus assay to detect genotoxic chemicals using young rats for several years, and had established its advantages with respect to using autonomous proliferation of young rat hepatocytes. Nine chemicals known to induce hepatotoxic effects such as necrosis (2,6-dinitrotolune, bromobenzene, isoniazid, phenacetin, allyl alcohol and thioacetamide), cholestasis (chlorpromazine hydrochloride and alpha-naphthyl isothiocyanate) and oxidative stress (clofibrate) were selected for this study. A liver micronucleus assay was conducted in 4-week-old male F344 rats using two or three dose levels of test chemicals given orally by gavage to evaluate the compound's ability to induce micronucleated hepatocytes. Several of these test chemicals were additionally examined in a peripheral blood micronucleus assay conducted concurrently and in the same animals. The genotoxic rodent hepatocarcinogen, 2,6-dinitrotoluene showed a positive result in the liver micronucleus assay, but the nongenotoxic hepatocarcinogens, clofibrate and thioacetamide gave negative responses. Bromobenzene, known to produce DNA adducts but is noncarcinogenic in rodent liver, was judged equivocal in this assay. alpha-Naphthyl isothiocyanate is noncarcinogenic and showed negative response in the liver. The other four chemicals, known to be either noncarcinogenic or carcinogenic in other non-liver target organs, showed negative results in the liver micronucleus assay. Based on the results in the present study and previous report described above, it was concluded that this technique is able to effectively predict genotoxic rodent hepatocarcinogenicity, and does not give false positives due to hepatotoxicity.

  20. Effect of sodium benzoate preservative on micronucleus induction, chromosome break, and Ala40Thr superoxide dismutase gene mutation in lymphocytes.

    PubMed

    Pongsavee, Malinee

    2015-01-01

    Sodium benzoate is food preservative that inhibits microbial growth. The effects of sodium benzoate preservative on micronucleus induction, chromosome break, and Ala40Thr superoxide dismutase gene mutation in lymphocytes were studied. Sodium benzoate concentrations of 0.5, 1.0, 1.5, and 2.0 mg/mL were treated in lymphocyte cell line for 24 and 48 hrs, respectively. Micronucleus test, standard chromosome culture technique, PCR, and automated sequencing technique were done to detect micronucleus, chromosome break, and gene mutation. The results showed that, at 24- and 48-hour. incubation time, sodium benzoate concentrations of 1.0, 1.5, and 2.0 mg/mL increased micronucleus formation when comparing with the control group (P < 0.05). At 24- and 48-hour. incubation time, sodium benzoate concentrations of 2.0 mg/mL increased chromosome break when comparing with the control group (P < 0.05). Sodium benzoate did not cause Ala40Thr (GCG→ACG) in superoxide dismutase gene. Sodium benzoate had the mutagenic and cytotoxic toxicity in lymphocytes caused by micronucleus formation and chromosome break.

  1. Lack of a correlation between micronucleus formation and radiosensitivity in established and primary cultures of human tumours.

    PubMed Central

    Villa, R.; Zaffaroni, N.; Gornati, D.; Costa, A.; Silvestrini, R.

    1994-01-01

    The radiation-induced genotoxic damage in three established cell lines and 15 primary cultures of human malignant melanoma and ovarian carcinoma showing different radiosensitivity was tested by the cytokinesis-block micronucleus assay. A dose-related increase in micronucleus frequency was observed in all the cell systems. The mean number of micronuclei per Gy of ionising radiation per binucleated cell was respectively 0.44 +/- 0.0075 and 0.43 +/- 0.04 for M14 and JR8 malignant melanoma cell lines and 0.19 +/- 0.013 for the A2780 ovarian cancer cell line. The number of micronuclei did not rank the cell lines in the same order of radiosensitivity as clonogenic cell survival, which showed a surviving fraction at 2 Gy of 0.38 +/- 0.02 for JR8, 0.34 +/- 0.05 for M14 and 0.22 +/- 0.007 for A2780. As regards primary tumour cultures, no correlation was observed between micronucleus induction and surviving fraction at 2 Gy. In conclusion, the discrepancy we observed between micronucleus formation and cell death raises doubts about the potential of the micronucleus assay as a preclinical means to predict radiosensitivity. Images Figure 1 PMID:7981062

  2. Recommended protocols for the liver micronucleus test: Report of the IWGT working group.

    PubMed

    Uno, Yoshifumi; Morita, Takeshi; Luijten, Mirjam; Beevers, Carol; Hamada, Shuichi; Itoh, Satoru; Ohyama, Wakako; Takasawa, Hironao

    2015-05-01

    At the 6th International Workshop on Genotoxicity Testing (IWGT), the liver micronucleus test working group discussed practical aspects of the in vivo rodent liver micronucleus test (LMNT). The group members focused on the three methodologies currently used, i.e., a partial hepatectomy (PH) method, a juvenile/young rat (JR) method, and a repeated-dose (RD) method in adult rodents. Since the liver is the main organ that metabolizes chemicals, the LMNT is expected to detect clastogens, especially those that need metabolic activation in the liver, and aneugens. Based on current data the three methods seem to have a high sensitivity and specificity, but more data, especially on non-genotoxic but toxic substances, would be needed to fully evaluate the test performance. The three methods can be combined with the micronucleus test (MNT) using bone marrow (BM) and/or peripheral blood (PB). The ability of the PH method to detect both clastogens and aneugens has already been established, but the methodology is technically challenging. The JR method is relatively straightforward, but animal metabolism might not be fully comparable to adult animals, and data on aneugens are limited. These two methods also have the advantage of a short testing period. The RD method is also straightforward and can be integrated into repeated-dose (e.g. 2 or 4 weeks) toxicity studies, but again data on aneugens are limited. The working group concluded that the LMNT could be used as a second in vivo test when a relevant positive result in in vitro mammalian cell genotoxicity tests is noted (especially under the condition of metabolic activation), and a negative result is observed in the in vivo BM/PB-MNT. The group members discussed LMNT protocols and reached consensus about many aspects of test procedures. However, data gaps as mentioned above remain, and further data are needed to fully establish the LMNT protocol.

  3. Determination of Genotoxic Effects of Hookah Smoking by Micronucleus and Chromosome Aberration Methods

    PubMed Central

    Eker, Ebru Derici; Koyuncu, Hayri; Şahin, Nefise Özlen; Yüksel, Altan; Berköz, Mehmet; Diler, Songul Budak; Akgül, Sema Altan

    2016-01-01

    Background Use of a hookah (a type of water pipe) is a traditional way of smoking tobacco, particularly in the Middle East. In Turkey, its popularity has been growing in recent years, especially among young people. It is known that cigarette smoking has genotoxic effects and causes mutations, but no comprehensive study has been done on the genotoxic effects of hookah usage, particularly in Turkey. Material/Methods We collected peripheral blood/buccal smear samples from 30 subjects who did not smoke cigarettes but who regularly smoke a hookah an average of 2 times per week, and from 30 control subjects who had never smoked cigarettes or a hookah. Chromosome analyses were performed on the samples obtained from peripheral blood of each individual, 25 metaphase plaques were counted for each, and chromosome/chromatid breakage/gap parameters were evaluated. Micronucleus analysis was done on buccal smear samples and micronucleus/binucleus parameters were investigated by counting 2000 cells of each individual. Results Chromosome breakage ratios were found to be 0.64±0.86 and 0.46±0.71 in the study and control groups, respectively, while chromatid breakage ratios were 0.53±0.83 and 0.53±0.71; fragment ratios were 0.82±1.24 and 0.21±0.49 (p<0.05); and gap ratios were 0.57±0.83 and 0.18±0.53 (p<0.05), respectively. Micronucleus ratio was 6.03±2.06 and 4.43±2.27 (p<0.05) in the study and control groups, respectively, and binucleus ratios were 8.53±3.23 and 12.15±5.18, respectively (p<0.05). Conclusions Results of our study reveal significant statistical differences between the individuals who smoked hookah and those who did not in terms of fragment, gap, micronucleus, and binucleus parameters, suggesting that smoking a hookah may cause genotoxic effects. PMID:27869111

  4. [The mutagenic and modifying properties of emoxipin studied by micronucleus assay in liver cells].

    PubMed

    Uryvaeva, I V; Delone, G V; Smirnov, L D

    1996-01-01

    Emoxypin is a medicinal drug from the group of 3-oxypyridines. We studied the capacity of emoxypin to affect the spontaneous level of micronuclear aberrations in the hepatocytes (to decrease or increase it by exerting a mutagenic effect) using the micronucleus test, as well as the capacity to modulate (enhance or weaken) the effects of nitrosomethylurea and X-irradiation. The results obtained do not suggest cytogenetic activity of emoxypin. The nature of "spontaneous" micronuclear aberrations in the liver are discussed, as well as the causes of their age-related increase and adequacy of this model to search for antimutagens.

  5. Low doses of ochratoxin A induce micronucleus formation and delay DNA repair in human lymphocytes.

    PubMed

    González-Arias, Cyndia A; Benitez-Trinidad, Alma B; Sordo, Monserrat; Robledo-Marenco, Lourdes; Medina-Díaz, Irma M; Barrón-Vivanco, Briscia S; Marín, Sonia; Sanchis, Vicente; Ramos, Antonio J; Rojas-García, Aurora E

    2014-12-01

    The contamination of food commodities by fungal toxins has attracted great interest because many of these mycotoxins are responsible for different diseases, including cancer and other chronic illnesses. Ochratoxin A (OTA) is a mycotoxin naturally present in food, and long-term exposure to food contaminated with low levels of OTA has been associated with renal cancer. In the present study, the cytotoxicity, cytostaticity, and genotoxicity of OTA (0.075-15 µM) in human lymphocytes were evaluated. A comet assay, a modified comet assay (DNA repair assay), which uses N-hydroxyurea (NHU) to detect non-repaired lesions produced by OTA, and a cytokinesis-blocked micronucleus assay were used. Treatments with OTA were not cytotoxic, but OTA caused a cytostatic effect in human lymphocytes at a concentration of 15 µM. OTA (0.075-5 µM) produced a slight increase in the percentage of DNA in the comets and a delay in the DNA repair capacity of the lymphocytes. Micronucleus (MN) induction was observed at OTA concentrations of 1.5 and 5 µM. Our results indicate that OTA induces DNA stable damage at low doses that are neither cytotoxic nor cytostatic, and OTA delays the DNA repair kinetics. These findings indicate that OTA affects two pivotal events in the carcinogenesis pathway.

  6. Origanum majorana Essential Oil Lacks Mutagenic Activity in the Salmonella/Microsome and Micronucleus Assays.

    PubMed

    Dantas, Andrea Dos Santos; Klein-Júnior, Luiz Carlos; Machado, Miriana S; Guecheva, Temenouga N; Dos Santos, Luciana D; Zanette, Régis A; de Mello, Fernanda B; Pêgas Henriques, João Antonio; de Mello, João Roberto Braga

    2016-01-01

    The present study aimed to investigate the in vitro mutagenic activity of Origanum majorana essential oil. The most abundant compounds identified by GC-MS were γ-terpinene (25.73%), α-terpinene (17.35%), terpinen-4-ol (17.24%), and sabinene (10.8%). Mutagenicity was evaluated by the Salmonella/microsome test using the preincubation procedure on TA98, TA97a, TA100, TA102, and TA1535 Salmonella typhimurium strains, in the absence or in the presence of metabolic activation. Cytotoxicity was detected at concentrations higher than 0.04 μL/plate in the absence of S9 mix and higher than 0.08 μL/plate in the presence of S9 mix and no gene mutation increase was observed. For the in vitro mammalian cell micronucleus test, V79 Chinese hamster lung fibroblasts were used. Cytotoxicity was only observed at concentrations higher than or equal to 0.05 μg/mL. Moreover, when tested in noncytotoxic concentrations, O. majorana essential oil was not able to induce chromosome mutation. The results from this study therefore suggest that O. majorana essential oil is not mutagenic at the concentrations tested in the Salmonella/microsome and micronucleus assays.

  7. Individual variations in the micronucleus assay for biological dosimetry after high dose exposure.

    PubMed

    Kacprzak, Justyna; Kuszewski, Tomasz; Lankoff, Anna; Müller, Wolfgang-Ulrich; Wojcik, Andrzej; Lisowska, Halina

    2013-08-30

    The micronucleus assay is widely used as a biological dosimeter. Due to an inhibitory effect of radiation on cell proliferation the assay yields satisfactory results only when the absorbed dose is below about 5Gy. In 2002 Müller and Rode suggested that a modified version of the test, based on the analysis of the ratio of trinucleated to tetranucleated cells and the frequency of micronuclei (Mn) in binucleated cells containing at least one Mn, can be applied to detect a dose reaching 15Gy (Mutat. Res. 502 (2002) 47-51). Their conclusion was based on the results of experiments with lymphocytes from one donor and nothing is known about the possible influence of individual variability on the applicability of the Mn test to detect high doses of radiation. The aim of the present study was to validate the modified micronucleus assay with lymphocytes of 5 donors. Their blood was exposed to 0, 5, 10, 15 and 20Gy of (60)Co gamma rays. The levels of Mn and of cell proliferation were assessed using various approaches. A strong inter-individual variability was observed for all endpoints. The results clearly show that the assessment of cell proliferation is essential for the interpretation of results. Unfortunately, it was not possible to identify one single proliferation marker that gives all necessary information.

  8. Origanum majorana Essential Oil Lacks Mutagenic Activity in the Salmonella/Microsome and Micronucleus Assays

    PubMed Central

    Klein-Júnior, Luiz Carlos; Guecheva, Temenouga N.; dos Santos, Luciana D.; Zanette, Régis A.; de Mello, Fernanda B.; de Mello, João Roberto Braga

    2016-01-01

    The present study aimed to investigate the in vitro mutagenic activity of Origanum majorana essential oil. The most abundant compounds identified by GC-MS were γ-terpinene (25.73%), α-terpinene (17.35%), terpinen-4-ol (17.24%), and sabinene (10.8%). Mutagenicity was evaluated by the Salmonella/microsome test using the preincubation procedure on TA98, TA97a, TA100, TA102, and TA1535 Salmonella typhimurium strains, in the absence or in the presence of metabolic activation. Cytotoxicity was detected at concentrations higher than 0.04 μL/plate in the absence of S9 mix and higher than 0.08 μL/plate in the presence of S9 mix and no gene mutation increase was observed. For the in vitro mammalian cell micronucleus test, V79 Chinese hamster lung fibroblasts were used. Cytotoxicity was only observed at concentrations higher than or equal to 0.05 μg/mL. Moreover, when tested in noncytotoxic concentrations, O. majorana essential oil was not able to induce chromosome mutation. The results from this study therefore suggest that O. majorana essential oil is not mutagenic at the concentrations tested in the Salmonella/microsome and micronucleus assays. PMID:27891531

  9. Evaluation of cytotoxic and genotoxic effects of Benodanil by using Allium and Micronucleus assays.

    PubMed

    Akyıl, Dilek; Özkara, Arzu; Erdoğmuş, S Feyza; Eren, Yasin; Konuk, Muhsin; Sağlam, Esra

    2016-01-01

    The aim of this study was to evaluate the potential cytotoxic effects of Benodanil fungicide by employing both mitotic index (MI) and mitotic phases on the root meristem cells of Allium cepa and genotoxic effects by using in vitro micronucleus assay (MN) in human peripheral blood lymphocyte. In the Allium root growth inhibition test, the EC50 value was first determined as 25 ppm. Then, 2 × EC50 value (50 ppm), EC50 value (25 ppm), and 1/2 × EC50 value (12.5 ppm) were tested with different treatment periods (24, 48, and 72 h). Both negative and positive controls were also used in parallel experiments. We obtained that mitotic index and prophase index decreased when compared with the control in all concentrations. In the micronucleus assay, lymphocytes were treated with various concentrations (250, 500, 750, and 1000 µg/ml) of Benodanil for 24 and 48 h. The results showed that Benodanil did not induce MN frequency in all concentrations of both treatment periods. Additionally, it was determined that this pesticide decreased nuclear division index (NDI) significantly. It was concluded that Benodanil has a cytotoxic effects depending on decreasing of MI and NDI.

  10. Comparative sensitivity of small mammals to micronucleus induction in bone marrow cells by clastogenic compounds

    SciTech Connect

    Meier, J.R.; Wernsing, P.; Daniel, F.B.; Torsella, J.

    1995-12-31

    The bone marrow micronucleus assay is the most widely used method for detecting genetic damage in vivo, but this assay has received little attention for its possible application to biomonitoring terrestrial environments. The present study compared the responsiveness of three small mammalian species, Cryptotus parva (least shrew), Peromyscus leucopus (white-footed mouse), and strain CD-1 Mus musculus (house mouse), to the clastogen, methylmethanesulfonate (MMS). Five animals of each sex of each species were exposed for 24 h to four concentrations of MMS ranging from 0 to 50 mg/kg. Bone marrow cells were flushed from the femurs, and smears were stained with acridine orange and examined using fluorescence microscopy. The slides were scored for evidence of acute bone marrow toxicity (polychromatic to normochromatic erythrocyte ratio, PCE:NCE) and frequency of micronucleated PCE. PCE:NCE was depressed at 50 mg/kg in P. leucopus, but not in the other species. Dose-related increases in micronucleated PCE were observed in all three species, with males being more sensitive for P. leucopus and M. musculus, and females being more sensitive for C. parva. For both sexes, the two feral species, P. leucopus and C. parva, were more sensitive than M. musculus. These studies demonstrate the successful application of the bone marrow micronucleus assay to species other than standard laboratory strains of mice. The results also demonstrate heretofore unrecognized species differences in responsiveness.

  11. Dependence of the bystander effect for micronucleus formation on dose of heavy-ion radiation in normal human fibroblasts.

    PubMed

    Matsumoto, Yoshitaka; Hamada, Nobuyuki; Aoki-Nakano, Mizuho; Funayama, Tomoo; Sakashita, Tetsuya; Wada, Seiichi; Kakizaki, Takehiko; Kobayashi, Yasuhiko; Furusawa, Yoshiya

    2015-09-01

    Ionising radiation-induced bystander effects are well recognised, but its dependence on dose or linear energy transfer (LET) is still a matter of debate. To test this, 49 sites in confluent cultures of AG01522D normal human fibroblasts were targeted with microbeams of carbon (103 keV µm(-1)), neon (375 keV µm(-1)) and argon ions (1260 keV µm(-1)) and evaluated for the bystander-induced formation of micronucleus that is a kind of a chromosome aberration. Targeted exposure to neon and argon ions significantly increased the micronucleus frequency in bystander cells to the similar extent irrespective of the particle numbers per site of 1-6. In contrast, the bystander micronucleus frequency increased with increasing the number of carbon-ion particles in a range between 1 and 3 particles per site and was similar in a range between 3 and 8 particles per site. These results suggest that the bystander effect of heavy ions for micronucleus formation depends on dose.

  12. Reference control data obtained from an in vivo comet-micronucleus combination assay using Sprague Dawley rats.

    PubMed

    Kasamoto, Sawako; Masumori, Shoji; Tanaka, Jin; Ueda, Maya; Fukumuro, Masahito; Nagai, Miho; Yamate, Jyoji; Hayashi, Makoto

    2017-04-04

    According to the International Conference on Harmonization Guidance on Genotoxicity Testing and Data Interpretation for Pharmaceuticals Intended for Human Use (ICH S2(R1)), a positive response in any in vitro assay necessitates additional in vivo test(s) (other tissue/endpoint) in addition to the erythrocyte micronucleus test when Option 1 of the test battery is selected. When Option 2 of the test battery is selected, a bacterial gene mutation test and two in vivo tests with different tissues/endpoint are required. The in vivo alkaline comet assay is recommended as the second in vivo test because it can detect a broad spectrum of DNA damage in any tissue and can be combined with the erythrocyte micronucleus test. Considering animal welfare, a combination assay is preferable to an individual assay. Thus, we validated the protocol for the in vivo comet-micronucleus combination assay in rats with three daily administrations and determined the dose of the positive control (ethyl methanesulfonate; EMS, 200mg/kg/day). We also collected the negative control (vehicle) and positive control (EMS) data from the comet (liver, stomach, and kidney) and micronucleus (bone marrow) combination assay using male Sprague Dawley (SD) rats. The negative control data were comparable to our historical control data obtained from stand-alone assays. The positive control data showed clear and consistent positive responses in both endpoints.

  13. REDUCTION OF GENOTOXICITY OF A CREOSOTE-CONTAMINATED SOIL AFTER FUNGAL TREATMENT DETERMINED BY THE TRADESCANTIA-MICRONUCLEUS TEST

    EPA Science Inventory

    The fungal degradation of polyaromatic hydrocarbons (PAH) in a contaminated soil from a hazarous waste site was evaluated in a pilot-scale study. As some PAH are known to be mutagens, the Tradescantia-micronucleus test (TRAD-MCN) was selected to evaluate the genotoxicity of the s...

  14. Soil genotoxicity assessment--results of an interlaboratory study on the Vicia micronucleus assay in the context of ISO standardization.

    PubMed

    Cotelle, Sylvie; Dhyèvre, Adrien; Muller, Serge; Chenon, Pascale; Manier, Nicolas; Pandard, Pascal; Echairi, Abdelwahad; Silvestre, Jérôme; Guiresse, Maritxu; Pinelli, Eric; Giorgetti, Lucia; Barbafieri, Meri; Silva, Valéria C; Engel, Fernanda; Radetski, Claudemir M

    2015-01-01

    The Vicia micronucleus assay was standardized in an international protocol, ISO 29200, "Assessment of genotoxic effects on higher plants-Vicia faba micronucleus test," for soil or soil materials (e.g., compost, sludge, sediment, waste, and fertilizing materials). The aim of this interlaboratory study on the Vicia micronucleus assay was to investigate the robustness of this in vivo assay in terms of its applicability in different countries where each participant were asked to use their own seeds and reference soil, in agreement with the ISO 29200 standard. The ISO 29200 standard protocol was adopted for this study, and seven laboratories from three countries (France, Italy, and Brazil) participated in the study. Negative and positive controls were correctly evaluated by 100 % of the participants. In the solid-phase test, the micronucleus frequency (number of micronuclei/1,000 cells) varied from 0.0 to 1.8 for the negative control (i.e., Hoagland's solution) and from 5.8 to 85.7 for the positive control (i.e., maleic hydrazide), while these values varied from 0.0 to 1.7 for the negative control and from 14.3 to 97.7 for the positive control in the case of liquid-phase test. The variability in the data obtained does not adversely affect the robustness of the protocol assessed, on the condition that the methodology described in the standard ISO 29200 is strictly respected. Thus, the Vicia micronucleus test (ISO 29200) is appropriate for complementing prokaryotic or in vitro tests cited in legislation related to risk assessment of genotoxicity potential.

  15. Evaluation of methyl methacrylate monomer cytotoxicity in dental lab technicians using buccal micronucleus cytome assay.

    PubMed

    Azhar, Dawasaz Ali; Syed, Sadatullah; Luqman, Master; Ali, Assiry A

    2013-01-01

    Methyl methacrylate (MMA) monomer, a primary component of dental resins, is known to induce cytotoxicity, dermatitis, and neuropathy. The objective of this study was to assess the incidence of micronuclei (MN) in buccal mucosal cells of dental technicians exposed to MMA using Buccal Micronucleus Cytome (BMCyt) assay. The Risk Group (RG=13) consisted of all the technicians working in the prosthetic production laboratory of KKU-College of Dentistry. The Control Group (CG=14) consisted of healthy students and doctors matching the age of RG subjects. Buccal mucosa scrapes obtained from all the 27 RG and CG subjects were stained with Papanicolaou stain and observed under oil immersion lens (100×) for the presence of MN. There were no significant differences in the incidence of MN between RG and CG (p>0.05).

  16. The 14-day repeated dose liver micronucleus test with methapyrilene hydrochloride using young adult rats.

    PubMed

    Inoue, Kenji; Ochi, Akimu; Koda, Akira; Wako, Yumi; Kawasako, Kazufumi; Doi, Takaaki

    2015-03-01

    The repeated dose liver micronucleus (RDLMN) assay using young adult rats has the potential to detect genotoxic hepatocarcinogens that can be integrated into a general toxicity study. The assay methods were thoroughly validated by 19 Japanese facilities. Methapyrilene hydrochloride (MP), known to be a non-genotoxic hepatocarcinogen, was examined in the present study. MP was dosed orally at 10, 30 and 100mg/kg/day to 6-week-old male Crl:CD (SD) rats daily for 14 days. Treatment with MP resulted in an increase in micronucleated hepatocytes (MNHEPs) with a dosage of only 100mg/kg/day. At this dose level, cytotoxicity followed by regenerative cell growth was noted in the liver. These findings suggest that MP may induce clastogenic effects indirectly on the liver or hepatotoxicity of MP followed by regeneration may cause increase in spontaneous incidence of MNHEPs.

  17. Genotoxic effect of Lythrum salicaria extract determined by the mussel micronucleus test.

    PubMed

    Eck-Varanka, Bettina; Kováts, Nóra; Hubai, Katalin; Paulovits, Gábor; Ferincz, Árpád; Horváth, Eszter

    2015-12-01

    A wide range of aquatic plants have been proven to release allelochemicals, of them phenolics and tannin are considered rather widely distributed. Tannins, however, have been demonstrated to have genotoxic capacity. In our study genotoxic potential of Lythrum salicaria L. (Purple Loosestrife, family Lythraceae) was assessed by the mussel micronucleus test, using Unio pictorum. In parallel, total and hydrolysable tannin contents were determined. Results clearly show that the extract had a high hydrolysable tannin content and significant mutagenic effect. As L. salicaria has been long used in traditional medicine for chronic diarrhoea, dysentery, leucorrhoea and blood-spitting, genotoxic potential of the plant should be evaluated not only with regard to potential effects in the aquatic ecosystem, but also assessing its safe use as a medicinal herb.

  18. The micronucleus test-most widely used in vivo genotoxicity test.

    PubMed

    Hayashi, Makoto

    2016-01-01

    Genotoxicity is commonly evaluated during the chemical safety assessment together with other toxicological endpoints. The micronucleus test is always included in many genotoxic test guidelines for long time in many classes of chemicals, e.g., pharmaceutical chemicals, agricultural chemicals, food additives. Although the trend of the safety assessment of chemicals faces to animal welfare and in vitro systems are more welcome than the in vivo systems, the in vivo test systems are paid more attention in the field of genotoxicity because of its weight of evidence. In this review, I will summarize the following points: 1) historical consideration of the test development, 2) characteristics of the test including advantages and limitations, 3) new approaches considering to the animal welfare.

  19. Lanthanum nitrate genotoxicity evaluation: Ames test, mouse micronucleus assay, and chromosome aberration test.

    PubMed

    Yang, Hui; Zhang, Xiaopeng; Liu, Haibo; Cui, Wenming; Zhang, Qiannan; Li, Yongning; Yu, Zhou; Jia, Xudong

    2016-11-01

    The increasing use of rare-earth elements (REE) and their compounds has led to their accumulation in the environment and has raised concern about their safety. The toxic effects of REE such as lanthanum are largely unknown; genotoxicity studies have been limited and results are controversial. We evaluated the genotoxicity of lanthanum nitrate (La(NO3)3) in several in vitro and in vivo tests, including bacterial reverse mutation assay (Ames test), mouse bone marrow micronucleus assay, and chromosome aberration assay. La(NO3)3 was not mutagenic in the Ames test. La(NO3)3 did not increase the frequencies of bone marrow micronuclei or chromosome aberration in the mouse after repeated treatments at oral doses up to 735 (females) and 855mg/kg (males). The compound did not increase the frequency of chromosome aberrations in CHO cells in vitro. These results indicate that lanthanum is not a genotoxic hazard.

  20. Micronucleus as biomarkers of cancer risk in anabolic androgenic steroids users.

    PubMed

    Souza, L da Cunha Menezes; da Cruz, L A; Cerqueira, E de Moraes Marcílio; Meireles, Jrc

    2017-03-01

    The use of anabolic androgenic steroids (AAS) has grown among practitioners of recreational bodybuilding, with significant contributions of designer steroids, aiming muscle hypertrophy in healthy subjects. The abusive use of AAS in general is associated with adverse effects; one of the most worrisome is cancer development. The aim of this study was to evaluate the effectiveness of the cytokinesis block micronucleus (CBMN) test in human lymphocytes in identifying risk groups for cancer development in users of AAS. Blood was collected from 15 AAS users bodybuilders (G1), 20 non-users bodybuilders (G2) and 20 non-users sedentary (G3). MN analysis was performed on a minimum of 1000 binucleated lymphocytes. The occurrence of MN was significantly higher ( p < 0.05) in individuals of G1 compared to G2 and G3. The results indicate the sensitivity of CBMN in human lymphocytes in the identification of chromosomal damage in consequence of AAS.

  1. The cytokinesis-block micronucleus assay as a biological dosimeter for targeted alpha therapy

    NASA Astrophysics Data System (ADS)

    Song, Emma Y.; Rizvi, Syed M. A.; Qu, Chang F.; Raja, Chand; Yuen, Johnson; Li, Yong; Morgenstern, Alfred; Apostolidis, Christos; Allen, Barry J.

    2008-01-01

    Ionizing radiation causes structural chromosomal aberrations, a proportion of which give rise to chromosome fragments without spindle attachment organelles. When a cell divides, some of these fragments are excluded from the main daughter nuclei and form small nuclei within the cytoplasm. The cytokinesis-block micronucleus assay allows these micronuclei (MN) to be counted, providing an in situ biological dosimeter. In this study, we evaluated the micronucleus frequency in peripheral blood lymphocytes after in vitro incubation with the alpha conjugates 213BiI3 and 213Bi-9.2.27 (AIC). Lymphocytes were inoculated in vitro AIC for 3 h. Further, we report the first MN measurements in melanoma patients after targeted alpha therapy (TAT) with 213Bi-9.2.27. Patients were injected with 260-360 MBq of AIC, and blood samples taken at 3 h, 2 weeks and 4 weeks post-treatment. Absorbed dose (MIRD) and effective total body dose (PED) were calculated. The MN frequency in lymphocytes was similar for equal in vitro incubation activities of 213BiI3 and 213Bi-9.2.27 (P = 0.5), indicating that there is no selective targeting of lymphocytes by the alpha conjugates. After inoculation with 10-1200 kBq mL - 1 of AIC, there was a substantial activity-related increase in MN. The number of MN in the blood of treated patients peaked at 3 h post-TAT, slowly returning to baseline levels by 4 weeks. The mean photon equivalent dose (PED) is 0.43 Gy (SD 0.15) and the mean MIRD calculated absorbed dose is 0.11 Gy (SD 0.03), giving an RBE = 4 ± 0.4 for this study.

  2. Micronucleus frequency in Danish schoolchildren and their mothers from the DEMOCOPHES population.

    PubMed

    Mørck, Thit A; Loock, Kim Vande; Poulsen, Maria Bech; Siersma, Volkert D; Nielsen, Jeanette K S; Hertel, Ole; Kirsch-Volders, Micheline; Knudsen, Lisbeth E

    2016-01-01

    Micronucleus (MN) frequency is a biomarker for early genetic effects which is often used in human biomonitoring studies. Increased frequency of micronuclei has been associated with high levels of traffic exposure. Further high MN frequency was found predictive for cancer development in several studies of adults. In the present study, the MN frequency in blood samples from the Danish participants of the European pilot project DEMOCOPHES was analysed and related to the area of residence, self-reported and calculated exposure to road traffic as well as to mercury in hair and blood concentrations of persistent organic pollutants and dioxin-like activity measured in the same participants. The MN frequency analysis was performed with the cytokinesis-block micronucleus (CBMN) assay and included 100 children and 119 mothers. We found a significant correlation between mothers and children in the levels of micronuclei in 1000 binucleated T lymphocytes (‰MNBN) and in the proliferation index. Further the levels of ‰MNBN were significantly higher in mothers compared with their children. No significant associations were found for ‰MNBN for traffic related exposure in neither children nor their mothers. In children, a 2.5 times higher micronuclei in mononuclear T lymphocytes were found in children living within 50 m of a busy road, however, this was not found in mothers or in MNBN and the effect of exposure to road traffic on MN frequency needs further investigation. No significant associations were found between MN frequencies and the other biomarkers measured in the same participants.

  3. Structural and numerical chromosome aberration inducers in liver micronucleus test in rats with partial hepatectomy.

    PubMed

    Itoh, Satoru; Hattori, Chiharu; Nagata, Mayumi; Sanbuissho, Atsushi

    2012-08-30

    The liver micronucleus test is an important method to detect pro-mutagens such as active metabolites not reaching bone marrow due to their short lifespan. We have already reported that dosing of the test compound after partial hepatectomy (PH) is essential to detect genotoxicity of numerical chromosome aberration inducers in mice [Mutat. Res. 632 (2007) 89-98]. In naive animals, the proportion of binucleated cells in rats is less than half of that in mice, which suggests a species difference in the response to chromosome aberration inducers. In the present study, we investigated the responses to structural and numerical chromosome aberration inducers in the rat liver micronucleus test. Two structural chromosome aberretion inducers (diethylnitrosamine and 1,2-dimethylhydrazine) and two numerical chromosome aberration inducers (colchicine and carbendazim) were used in the present study. PH was performed a day before or after the dosing of the test compound in 8-week old male F344 rats and hepatocytes were isolated 4 days after the PH. As a result, diethylnitrosamine and 1,2-dimethylhydrazine, structural chromosome aberration inducers, exhibited significant increase in the incidence of micronucleated hepatocyte (MNH) when given either before and after PH. Colchicine and carbendazim, numerical chromosome aberration inducers, did not result in any toxicologically significant increase in MNH frequency when given before PH, while they exhibited MNH induction when given after PH. It is confirmed that dosing after PH is essential in order to detect genotoxicity of numerical chromosome aberration inducers in rats as well as in mice. Regarding the species difference, a different temporal response to colchicine was identified. Colchicine increased the incidence of MNH 4 days after PH in rats, although such induction in mice was observed 8-10 days after PH.

  4. The micronucleus test and NTP rodent carcinogens: not so many false negatives.

    PubMed

    Galloway, S M

    1996-06-10

    In the study by Shelby et al. (1993) on 49 chemicals, the results of the micronucleus (MN) test in mouse bone marrow were compared with the results of the 2 year rodent carcinogenicity assays. Seven of the 25 rodent carcinogens were considered positive in the MN test, 5 following a protocol in which chemicals were given in three daily doses, and a further 2 when the chemical was administered only once. This low rate of positive results has led to disappointment in the MN test as a screen for carcinogens, but a careful examination of the data and of its analysis by Shelby et al. (1993) shows that many of the negative results are appropriate because: of the 18 carcinogens that were negative in the MN test, 1 has been retested and found to be non-carcinogenic, 9 were non-genotoxic and at least 2 were site-of-contact carcinogens not expected to be detected in the bone marrow. Two others were clearly positive in the MN test in other labs. Thus, the MN test 'missed' not 18 carcinogens, but 4 genotoxic carcinogens. The significance of these 4 needs further assessment, since three were liver specific carcinogens and the fourth was a very weak inducer of hemangiosarcomas in female mice only. Overall, the results of Shelby et al. (1993) do not cast such a shadow on the micronucleus test as many feared, and must be examined in the context of all the information available on each chemical. As Ashby and Tinwell emphasize in the accompanying article and in Tinwell and Ashby (1994), the data show that the MN test is capable of identifying human carcinogens and rodent germ cell mutagens, and remains a useful part of genotoxicity evaluation of chemicals.

  5. Evaluation of micronucleus induction of sand dust storm fine particles (PM(2.5)) in human blood lymphocytes.

    PubMed

    Wei, Aili; Meng, Ziqiang

    2006-11-01

    Sand dust storms are common phenomena in the arid and semi-arid regions. Previous studies have demonstrated that the airborne air fine particulate matter (PM(2.5), particulates with an aerodynamic diameter ≤2.5μm) and its extracts can induce human genetic damage of lymphocytes such as micronucleus formation, chromosomal aberration and so on. However, little is known about the health risks associated with sand dust storm PM(2.5) and its extracts. The aim of the present study is to investigate the micronucleus induction of sand dust storm PM(2.5) (include its organic and inorganic extract) from two different towns on human lymphocytes. The samples of normal PM(2.5) and sand dust storm PM(2.5) were collected in Wuwei (Gansu Province) and Baotou (Inner Mongolia), China. The cytochalasin-B cytokinesis-block test was employed and the cells were treated with 0, 33, 100, 300μgml(-1) sand dust storm PM(2.5) or normal ambient air PM(2.5) suspension (physiological saline as solvent control), or inorganic extract (0, 75, 150, 300μgml(-1), physiological saline as solvent control) or organic extract (0, 20, 40, 80μgml(-1), DMSO as solvent control) at the beginning of the cell culture. Both sand dust storm and normal PM(2.5) and their extract treatment cultures revealed an increase in the frequency of micronucleus. With the increase of treatment concentrations the frequency of micronucleus increased and the nuclear division index (NDI) values declined in a dose-response manner (P<0.01). In the same concentrates, the frequency of micronucleus of normal ambient air PM(2.5) and its extract were significant higher than those of sand dust storm PM(2.5) (P<0.01) except the treatment of Wuwei sample at higher doses, the treatment of inorganic extract of PM(2.5) at the highest dose (300μgml(-1)) and the treatment of organic extract of PM(2.5) at the higher dose (40 and 80μgml(-1)) either in Baotou or in Wuwei (P>0.05). The toxicity of sand dust storm PM(2.5) and its extract at

  6. Genotoxicity studies on the azo dye Direct Red 2 using the in vivo mouse bone marrow micronucleus test.

    PubMed

    Rajaguru, P; Fairbairn, L J; Ashby, J; Willington, M A; Turner, S; Woolford, L A; Chinnasamy, N; Rafferty, J A

    1999-07-21

    The clastogenicity of the azo dye Direct Red 2 (DR2) has been investigated using the murine bone marrow micronucleus assay. A potent dose-dependent response was observed following oral gavage of DR2 up to 4 mg/kg, after which significant toxicity to the erythroid compartment was observed. The route of administration had a significant effect on the frequency of micronucleus formation: intraperitoneal injection was approximately two-fold less clastogenic than the equivalent dose delivered orally (p<0.05). The requirement for activation of DR2 by intestinal microflora was indicated by the fact that mice given acid-treated water prior to administration of DR2 showed a significant reduction (40%; p<0.001) in micronucleated polychromatic erythrocyte formation. The implications of these findings for the health and safety of occupationally exposed workers are discussed.

  7. Antimutagenic, Antigenotoxic, and Anticytotoxic Activities of Silybum Marianum [L.] Gaertn Assessed by the Salmonella Mutagenicity Assay (Ames Test) and the Micronucleus Test in Mice Bone Marrow.

    PubMed

    Borges, Flávio Fernandes Veloso; Silva, Carolina Ribeiroe; Véras, Jefferson Hollanda; Cardoso, Clever Gomes; da Cruz, Aparecido Divino; Chen, Lee Chen

    2016-07-01

    Silymarin (SM), a standardized extract from Silybum marianum (L.) Gaertn., is composed mainly of flavonolignans, and silibinin (SB) is its major active constituent. The present study aimed to evaluate the antimutagenic activities of SM and SB using the Ames mutagenicity test in Salmonella Typhimurium, as well as their anticytotoxic and antigenotoxic activities using the mouse bone marrow micronucleus test. To assess antimutagenicity, Salmonella Typhimurium strains were treated with different concentrations of SM or SB and the appropriate positive control for each strain. To assess antigenotoxicity and anticytotoxicity, Swiss mice were treated with different concentrations of SM or SB and mitomycin C (MMC). The results showed that SM was not significantly effective in reducing the number of frameshift mutations in strain TA98, while SB demonstrated significant protection at higher doses (P < 0.05). Regarding strain TA 100, SM and SB significantly decreased mutagenicity (point mutations) (P < 0.05). The results of the antigenotoxic evaluation demonstrated that SM and SB significantly reduced the frequency of micronucleated polychromatic erythrocytes (MNPCE) (P < 0.05). The results also indicated that SM and SB significantly attenuated MMC-induced cytotoxicity (P < 0.05). Based on these results, both SM and SB presented antimutagenic, antigenotoxic, and anticytotoxic actions.

  8. Dose estimation using dicentric chromosome assay and cytokinesis block micronucleus assay: comparison between manual and automated scoring in triage mode.

    PubMed

    De Amicis, Andrea; De Sanctis, Stefania; Di Cristofaro, Sara; Franchini, Valeria; Regalbuto, Elisa; Mammana, Giacomo; Lista, Florigio

    2014-06-01

    In cases of an accidental overexposure to ionizing radiation, it is essential to estimate the individual absorbed dose of a potentially radiation-exposed person. For this purpose, biological dosimetry can be performed to confirm, complement or even replace physical dosimetry when this proves to be unavailable. The most validated biodosimetry techniques for dose estimation are the dicentric chromosome assay, the "gold standard" for individual dose assessment, and cytokinesis-block micronucleus assay. However, both assays are time consuming and require skilled scorers. In case of large-scale accidents, different strategies have been developed to increase the throughput of cytogenetic service laboratories. These are the decrease of cell numbers to be scored for triage dosimetry; the automation of procedures including the scoring of, for example, aberrant chromosomes and micronuclei; and the establishment of laboratory networks in order to enable mutual assistance if necessary. In this study, the authors compared the accuracy of triage mode biodosimetry by dicentric chromosome analysis and the cytokinesis block micronucleus assay performing both the manual and the automated scoring mode. For dose estimation using dicentric chromosome assay of 10 blind samples irradiated up to 6.4 Gy of x-rays, a number of metaphase spreads were analyzed ranging from 20 up to 50 cells for the manual and from 20 up to 500 cells for the automatic scoring mode. For dose estimation based on the cytokinesis block micronucleus assay, the micronucleus frequency in both 100 and 200 binucleated cells was determined by manual and automatic scoring. The results of both assays and scoring modes were compared and analyzed considering the sensitivity, specificity, and accuracy of dose estimation with regard to the discrimination power of clinically relevant binary categories of exposure doses.

  9. Micronucleus frequency in children exposed to biomass burning in the Brazilian Legal Amazon region: a control case study

    PubMed Central

    2012-01-01

    Background The Amazon represents an area of 61% of Brazilian territory and is undergoing major changes resulting from disorderly economic development, especially the advance of agribusiness. Composition of the atmosphere is controlled by several natural and anthropogenic processes, and emission from biomass burning is one with the major impact on human health. The aim of this study was to evaluate genotoxic potential of air pollutants generated by biomass burning through micronucleus assay in exfoliated buccal cells of schoolchildren in the Brazilian Amazon region. Methods The study was conducted during the dry seasons in two regions of the Brazilian Amazon. The assay was carried out on buccal epithelial cells of 574 schoolchildren between 6-16 years old. Results The results show a significant difference between micronucleus frequencies in children exposed to biomass burning compared to those in a control area. Conclusions The present study demonstrated that in situ biomonitoring using a sensitive and low cost assay (buccal micronucleus assay) may be an important tool for monitoring air quality in remote regions. It is difficult to attribute the increase in micronuclei frequency observed in our study to any specific toxic element integrated in the particulate matters. However, the contribution of the present study lies in the evidence that increased exposure to fine particulate matter generates an increased micronuclei frequency in oral epithelial cells of schoolchildren. PMID:22400801

  10. The cytokinesis-blocked micronucleus assay: dose estimation and inter-individual differences in the response to γ-radiation.

    PubMed

    Antunes, A C; Martins, V; Cardoso, J; Santos, L; Monteiro Gil, O

    2014-01-15

    Biological dosimetry plays an important role in case of a radiation accident or incident, either when it is the only way to estimate the dose or when it is used to complement physical dosimetry. A cytogenetic study was conducted in a group of 16 Portuguese individuals by use of the cytokinesis-blocked micronucleus (CBMN) assay. A dose-response curve for micronuclei yield was established with a linear-quadratic model: Y=(0.0122±0.0010)+(0.0241±0.0023)D+(0.0193±0.0007)D(2). Also, baseline values for the micronucleus formation in the 16 donors were analyzed, with results in close agreement with those from other laboratories. A validation experiment was carried out with three individuals. The real and the estimated doses obtained with the dose-response curve were in very good agreement, allowing the use of the micronucleus dose-response calibration curve in biological dosimetry for estimation of radiation dose in case of overexposure. The results obtained for the cytogenetic endpoints, studied in the same group of 16 individuals, were also analyzed as a function of age and gender. A higher inter-variability was observed for the higher dose points and differences in response were identified between genders, above 2Gy, for all endpoints.

  11. Genotoxic and cytotoxic evaluation of Jatropha dioica Sessé ex Cerv. by the micronucleus test in mouse peripheral blood.

    PubMed

    Araujo-Espino, Diana Isela; Zamora-Perez, Ana Lourdes; Zúñiga-González, Guillermo Moisés; Gutiérrez-Hernández, Rosalinda; Morales-Velazquez, Gabriela; Lazalde-Ramos, Blanca Patricia

    2017-03-23

    Jatropha dioica Sessé ex Cerv. is a medicinal plant credited with low cytotoxicity in vitro. Thus, the objective of this work was to evaluate the possible genotoxic and cytotoxic effect in vivo of the J. dioica aqueous extract by means of micronucleus assay in mouse peripheral blood. Four different J. dioica aqueous extract dose-units were evaluated (30, 60, 100, and 300 mg/kg). The extract was administered orally to male Balb-C-strain mice every 24 h during 5 days. Blood samples were taken at 0, 24, 48, 72, 96, and 120 h from the mouse's tail and were performed in duplicate extensions. The number of Polychromatic Erythrocytes (PCE), Polychromatic Micronucleus Erythrocytes (PCEMN), and Micronucleus Erythrocytes (MNE) was determined at the different sampling times in the different study groups. Our results showed that the group that received 60 mg/kg of cyclophosphamide (positive control) presented a significant decrease in the PCE (p = 0.044) proportion and a significant increase in MNE (p = 0.032, p = 0.0001). The groups that received the different J. dioica aqueous extract doses did not present either a PCE decrease or an increase in PCEMN and MNE. J. dioica exerts neither a genotoxic nor a cytotoxic effect on mouse peripheral blood at high doses.

  12. Clinical application of micronucleus test: a case-control study on the prediction of breast cancer risk/susceptibility.

    PubMed

    Bolognesi, Claudia; Bruzzi, Paolo; Gismondi, Viviana; Volpi, Samantha; Viassolo, Valeria; Pedemonte, Simona; Varesco, Liliana

    2014-01-01

    The micronucleus test is a well-established DNA damage assay in human monitoring. The test was proposed as a promising marker of cancer risk/susceptibility mainly on the basis of studies on breast cancer. Our recent meta-analysis showed that the association between micronuclei frequency, either at baseline or after irradiation, and breast cancer risk or susceptibility, has been evaluated in few studies of small size, with inconsistent results. The aim of the present study is to investigate the role of micronucleus assay in evaluating individual breast cancer susceptibility. Two-hundred and twenty untreated breast cancer patients and 295 female controls were enrolled in the study. All women were characterized for cancer family history and 155 subjects were evaluated for the presence of BRCA mutations. Micronuclei frequency was evaluated at baseline and after irradiation with 1-Gy gamma rays from a 137Cs source. The results show a non significant increase of frequency of micronucleated binucleated lymphocytes in cancer patients compared with the controls at baseline (Mean (S.E.): 16.8 (0.7) vs 15.7 (0.5), but not after irradiation (Mean (S.E.): 145.8 (3.0) vs 154.0 (2.6)). Neither a family history of breast cancer nor the presence of a pathogenic mutation in BRCA1/2 genes were associated with an increased micronuclei frequency. Our results do not support a significant role of micronucleus frequency as a biomarker of breast cancer risk/susceptibility.

  13. Analysis of the Genotoxic Effects of Mobile Phone Radiation using Buccal Micronucleus Assay: A Comparative Evaluation

    PubMed Central

    Singh, Narendra Nath; Sreedhar, Gadiputi; Mukherjee, Saikat

    2016-01-01

    Introduction Micronucleus (MN) is considered to be a reliable marker for genotoxic damage and it determines the presence and the extent of the chromosomal damage. The MN is formed due to DNA damage or chromosomal disarrangements. The MN has a close association with cancer incidences. In the new era, mobile phones are constantly gaining popularity specifically in the young generation, but this device uses radiofrequency radiation that may have a possible carcinogenic effect. The available reports related to the carcinogenic effect of mobile radiation on oral mucosa are contradictory. Aim To explore the effects of mobile phone radiation on the MN frequency in oral mucosal cells. Materials and Methods The subjects were divided into two major groups: low mobile phone users and high mobile phone users. Subjects who used their mobile phone since less than five years and less than three hours a week comprised of the first group and those who used their mobile since more than five years and more than 10 hours a week comprised of the second group. Net surfing and text messaging was not considered in this study. Exfoliated buccal mucosal cells were collected from both the groups and the cells were stained with DNA-specific stain acridine orange. Thousand exfoliated buccal mucosal cells were screened and the cells which were positive for micronuclei were counted. The micronucleus frequency was represented as mean±SD, and unpaired Student t-test was used for intergroup comparisons. Results The number of micronucleated cells/ 1000 exfoliated buccal mucosal cells was found to be significantly increased in high mobile phone users group than the low mobile phone users group. The use of mobile phone with the associated complaint of warmth around the ear showed a maximum increase in the number of micronucleated cells /1000 exfoliated buccal mucosal cells. Conclusion Mobile phone radiation even in the permissible range when used for longer duration causes significant genotoxicity

  14. Low-Dose Gamma Radiation Does Not Induce an Adaptive Response for Micronucleus Induction in Mouse Splenocytes.

    PubMed

    Bannister, L A; Serran, M L; Mantha, R R

    2015-11-01

    Low-dose ionizing radiation is known to induce radioadaptive responses in cells in vitro as well as in mice in vivo. Low-dose radiation decreases the incidence and increases latency for spontaneous and radiation-induced tumors in mice, potentially as a result of enhanced cellular DNA repair efficiency or a reduction in genomic instability. In this study, the cytokinesis-block micronucleus (CBMN) assay was used to examine dose response and potential radioadaptive response for cytogenetic damage and cell survival in C57BL/6 and BALB/c spleen cells exposed in vitro or in vivo to low-dose 60Co gamma radiation. The effects of genetic background, radiation dose and dose rate, sampling time and cell cycle were investigated with respect to dose response and radioadaptive response. In C57BL/6 mice, a linear-quadratic dose-response relationship for the induction of micronuclei (MN) was observed for doses between 100 mGy and 2 Gy. BALB/c mice exhibited increased radiosensitivity for MN induction compared to C57BL/6 mice. A 20 mGy dose had no effect on MN frequencies in splenocytes of either mouse strain, however, increased spleen weight and a reduced number of dead cells were noted in the C57BL/6 strain only. Multiple experimental parameters were investigated in radioadaptive response studies, including dose and dose rate of the priming dose (20 mGy at 0.5 mGy/min and 100 mGy at 10 mGy/min), time interval (4 and 24 h) between priming and challenge doses, cell cycle stage (resting or proliferating) at exposure and kinetics after the challenge dose. Radioadaptive responses were not observed for MN induction for either mouse strain under any of the experimental conditions investigated. In contrast, a synergistic response for radiation-induced micronuclei in C57BL/6 spleen was detected after in vivo 20 mGy irradiation. This increase in the percentage of cells with cytogenetic damage was associated with a reduction in the number of nonviable spleen cells, suggesting that low

  15. [Influence of Four Kinds of PPCPs on Micronucleus Rate of the Root-Tip Cells of Vicia-faba and Garlic].

    PubMed

    Wang, Lan-jun; Wang, Jin-hua; Zhu, Lu-sheng; Wang, Jun; Zhao, Xiang

    2016-04-15

    In order to determine the degree of biological genetic injury induced by PPCPs, the genotoxic effects of the doxycycline (DOX), ciprofloxacin (CIP), triclocarban (TCC) and carbamazepine (CBZ) in the concentration range of 12.5-100 mg · L⁻¹ were studied using micronucleus rate and micronucleus index of Vicia-fabe and garlic. The results showed that: (1) When the Vicia-faba root- tip cells were exposed to DOX, CIP, TCC and CBZ, micronucleus rates were higher than 1.67 ‰ (CK₁), it was significantly different from that of the control group (P < 0.05), and the micronucleus index was even greater than 3.5; With the increasing concentrations of the PPCPs, the micronucleus rates first increased and then decreased. (2) When the garlic root tip cells were exposed to DOX, CIP, TCC and CBZ respectively, the micronucleus rates were less than those of the Vicia-faba, while in most treatments significantly higher than that of the control group (0.67‰). The micronucleus index was higher than 3.5 in the groups exposed to CIP with concentrations of 25, 50, 100 mg · L⁻¹ and TCC and CBZ with concentrations of 25 mg · L⁻¹; With the increase of exposure concentrations, the micronucleus rate showed a trend of first increasing and then decreasing as well. (3) Under the same experimental conditions, the cells micronucleus rates of the garlic cells caused by the four tested compounds were significantly lower than those of Vicia-faba. (4) The micronucleus index of the root tip cells of Vicia-faba and garlic treated with the four kinds of compounds followed the order of CIP > CBZ > TCC > DOX. These results demonstrated that the four compounds caused biological genetic injury to root-tip cells of Vicia-faba and garlic, and the genetic damage caused to garlic was significantly lower than that to Vicia-faba. The damages caused by the four kinds of different compounds were also different.

  16. Automation and validation of micronucleus detection in the 3D EpiDerm™ human reconstructed skin assay and correlation with 2D dose responses

    PubMed Central

    Chapman, K. E.; Thomas, A. D.; Jenkins, G. J. S.

    2014-01-01

    Recent restrictions on the testing of cosmetic ingredients in animals have resulted in the need to test the genotoxic potential of chemicals exclusively in vitro prior to licensing. However, as current in vitro tests produce some misleading positive results, sole reliance on such tests could prevent some chemicals with safe or beneficial exposure levels from being marketed. The 3D human reconstructed skin micronucleus (RSMN) assay is a promising new in vitro approach designed to assess genotoxicity of dermally applied compounds. The assay utilises a highly differentiated in vitro model of the human epidermis. For the first time, we have applied automated micronucleus detection to this assay using MetaSystems Metafer Slide Scanning Platform (Metafer), demonstrating concordance with manual scoring. The RSMN assay’s fixation protocol was found to be compatible with the Metafer, providing a considerably shorter alternative to the recommended Metafer protocol. Lowest observed genotoxic effect levels (LOGELs) were observed for mitomycin-C at 4.8 µg/ml and methyl methanesulfonate (MMS) at 1750 µg/ml when applied topically to the skin surface. In-medium dosing with MMS produced a LOGEL of 20 µg/ml, which was very similar to the topical LOGEL when considering the total mass of MMS added. Comparisons between 3D medium and 2D LOGELs resulted in a 7-fold difference in total mass of MMS applied to each system, suggesting a protective function of the 3D microarchitecture. Interestingly, hydrogen peroxide (H2O2), a positive clastogen in 2D systems, tested negative in this assay. A non-genotoxic carcinogen, methyl carbamate, produced negative results, as expected. We also demonstrated expression of the DNA repair protein N-methylpurine-DNA glycosylase in EpiDerm™. Our preliminary validation here demonstrates that the RSMN assay may be a valuable follow-up to the current in vitro test battery, and together with its automation, could contribute to minimising unnecessary in

  17. Assessment of the genotoxicity of quinolone and fluoroquinolones contaminated soil with the Vicia faba micronucleus test.

    PubMed

    Khadra, A; Pinelli, E; Lacroix, M Z; Bousquet-Melou, A; Hamdi, H; Merlina, G; Guiresse, M; Hafidi, M

    2012-02-01

    The genotoxicity of quinolone and fluroquinolones was assessed using the micronucleus (MN) test on Vicia faba roots by direct contact exposure to a solid matrix. Plants were exposed to quinolones (nalidixic acid) and fluoroquinolones (ciprofloxacin and enrofloxacin) alone or mixed with artificially contaminated soils. Four different concentrations of each of these antibiotics were tested (0.01, 0.1, 1 and 10 mg/Kg) for nalidixic acid and (0.005, 0.05, 0.5 and 5 mg/Kg) for ciprofloxacin and enrofloxacin. These antibiotics were also used in mixture. Exposure of Vicia faba plants to each antibiotic at the highest two concentrations showed significant MN induction. The lowest two concentrations had no significant genotoxic effect. The mixture of the three compounds induced a significant MN induction whatever the mixture tested, from 0.02 to 20 mg/Kg. The results indicated that a similar genotoxic effect was obtained with the mixture at 0.2 mg/Kg in comparison with each molecule alone at 5-10 mg/Kg. Data revealed a clear synergism of these molecules on Vicia faba genotoxicity.

  18. A high-throughput in vivo micronucleus assay for genome instability screening in mice

    PubMed Central

    Balmus, Gabriel; Karp, Natasha A; Ng, Bee Ling; Jackson, Stephen P; Adams, David J; McIntyre, Rebecca E

    2016-01-01

    We describe a sensitive, robust, high-throughput method for quantifying the formation of micronuclei, markers of genome instability, in mouse erythrocytes. Micronuclei are whole chromosomes or chromosome segments that have been separated from the nucleus. Other methods of detection rely on labour-intensive, microscopy-based techniques. Here, we describe a 2-d, 96-well plate-based flow cytometric method of micronucleus scoring that is simple enough for a research technician experienced in flow cytometry to perform. The assay detects low levels of genome instability that cannot be readily identified by classic phenotyping, using 25 μl of blood. By using this assay, we have screened >10,000 blood samples and discovered novel genes that contribute to vertebrate genome maintenance, as well as novel disease models and mechanisms of genome instability disorders. We discuss experimental design considerations, including statistical power calculation, we provide troubleshooting tips, and we discuss factors that contribute to a false-positive increase in the number of micronucleated red blood cells and to experimental variability. PMID:25551665

  19. In vitro genotoxicity testing of carvacrol and thymol using the micronucleus and mouse lymphoma assays.

    PubMed

    Maisanaba, Sara; Prieto, Ana I; Puerto, Maria; Gutiérrez-Praena, Daniel; Demir, Eşref; Marcos, Ricard; Cameán, Ana M

    2015-06-01

    Currently, antimicrobial additives derived from essential oils (Eos) extracted from plants or spices, such as Origanum vulgare, are used in food packaging. Thymol and carvacrol, the major EO compounds of O. vulgare, have demonstrated their potential use as active additives. These new applications use high concentrations, thereby increasing the concern regarding their toxicological profile and especially their genotoxic risk. The aim of this work was to investigate the potential in vitro genotoxicity of thymol (0-250 μM) and carvacrol (0-2500 μM) at equivalent doses to those used in food packaging. The micronucleus (MN) test and the mouse lymphoma (MLA) assay on L5178Y/Tk(±) mouse lymphoma cells were used. The negative results for thymol with the MN with and without the S9 fraction and also with the MLA assay reinforce the view that this compound is not genotoxic in mammalian cells. However, carvacrol presented slight genotoxic effects, but only in the MN test at the highest concentration assayed (700 μM) and in the absence of metabolic activation. The lack of genotoxic response in the MLA assay after 4 and 24h of exposure indicates a low genotoxic potential for carvacrol. Alternatively, the general negative findings observed in both assays suggest that the MN results of carvacrol are marginal data without biological relevance. These results can be useful to identify the appropriate concentrations of these substances to be used as additives in food packaging.

  20. Genetic damage in coal miners evaluated by buccal micronucleus cytome assay.

    PubMed

    León-Mejía, Grethel; Quintana, Milton; Debastiani, Rafaela; Dias, Johnny; Espitia-Pérez, Lyda; Hartmann, Andreas; Henriques, João Antônio Pêgas; Da Silva, Juliana

    2014-09-01

    During coal mining activities, large quantities of coal dust, ashes, polycyclic aromatic hydrocarbons and metals are released into the environment. This complex mixture presents one of the most important occupational hazards for health of workers. The aim of the present study was to evaluate the genetic damage together with the presence of inorganic elements, in an exposed workers population to coal mining residues of Guajira-Colombia. Thus, 100 exposed workers and 100 non-exposed control individuals were included in this study. To determine genetic damage we assessed the micronucleus (MN) frequencies and nuclear buds in buccal mucosa samples (BMCyt) assay, which were significantly higher in the exposed group than non-exposed control group. In addition, karyorrhectic and karyolytic cells were also significantly higher in the exposed group (cell death). No significant difference was observed between the exposed groups engaged in different mining activities. No correlation between age, alcohol consumption, time of service and MN assay data were found in this study. However, the content of inorganic elements in blood samples analyzed by a Particle-induced X-ray emission technique (PIXE) showed higher values of silicon (Si) and aluminum (Al) in the exposed group. In this study we discuss the possibility of DNA damage observed in the mine workers cells be a consequence of oxidative damage.

  1. Effect of mobile phone station on micronucleus frequency and chromosomal aberrations in human blood cells.

    PubMed

    Yildirim, M S; Yildirim, A; Zamani, A G; Okudan, N

    2010-01-01

    The use of mobile telephones has rapidly increased worldwide as well as the number of mobile phone base stations that lead to rise low level radiofrequency emissions which may in turn have possible harm for human health. The national radiation protection board has published the known effects of radio waves exposure on humans living close to mobile phone base stations. However, several studies have claimed that the base station has detrimental effects on different tissues. In this study, we aimed to evaluate the effects of mobile phone base stations on the micronucleus (MN) frequency and chromosomal aberrations on blood in people who were living around mobile phone base stations and healthy controls. Frequency of MN and chromosomal aberrations in study and control groups was 8.96 +/- 3.51 and 6.97 +/- 1.52 (p: 0.16); 0.36 +/- 0.31 and 0.75 +/- 0.61 (p: 0.07), respectively. Our results show that there was not a significant difference of MN frequency and chromosomal aberrations between the two study groups. The results claim that cellular phones and their base stations do not produce important carcinogenic changes.

  2. Frequency of micronucleus in oral epithelial cells after exposure to mate-tea in healthy humans

    PubMed Central

    Campagnoli, Eduardo B.; Milan, José R.; Reinheimer, Angélica; Masson, Maicon; Capella, Diogo L.

    2014-01-01

    Objectives: The aim of this study was to evaluate the possibility of technique simplification for cytology slides in order to evaluate the frequency of micronuclei (FMic) and conduct a experiment looking to know the FMic of oral epithelial cells of healthy volunteers exposed to mate tea (Ilex paraguarariensis). Material and Methods: This is a laboratorial and nonrandomized trial (quasi-experiment), where the nonusers subjects were exposed to mate-tea, consumed in the traditional way, two drinks, two times a day for a single week. Two cytology of exfoliated epithelial cells were obtained before and after the mate tea exposition. Results: The sample was composed by 10 volunteers. The age ranged from 18 to 33 years (Mean 23; SD5.5). The use of mate tea did not showed significant variation in the FMic (Wilcoxon Signed Ranks Test p= .24). Conclusions: The proposed technique simplification showed to be reliable, without losses when compared to the conventional technique and with the advantage of eliminate toxic substances, becoming simple and practical tool for research in dentistry. The acute exposure to mate tea did not induce an increase of FMic in exfoliated buccal cells of healthy nondrinkers and nonsmokers subjects and may not have genotoxic effect. More human studies are needed before a conclusion can be made on the oral carcinogenic risk of mate tea to humans. Key words:Micronucleus, Oral Cancer, Cytology, Mate tea, Ilex paraguariensis. PMID:24608213

  3. Fast Image Analysis for the Micronucleus Assay in a Fully Automated High-Throughput Biodosimetry System

    PubMed Central

    Lyulko, Oleksandra V.; Garty, Guy; Randers-Pehrson, Gerhard; Turner, Helen C.; Szolc, Barbara; Brenner, David J.

    2014-01-01

    The development of, and results from an image analysis system are presented for automated detection and scoring of micronuclei in human peripheral blood lymphocytes. The system is part of the Rapid Automated Biodosimetry Tool, which was developed at the Center for High-Throughput Minimally Invasive Radiation Biodosimetry for rapid radiation dose assessment of many individuals based on single fingerstick samples of blood. Blood lymphocytes were subjected to the cytokinesis-block micronucleus assay and the images of cell cytoplasm and nuclei are analyzed to estimate the frequency of micronuclei in binucleated cells. We describe an algorithm that is based on dual fluorescent labeling of lymphocytes with separate analysis of images of cytoplasm and nuclei. To evaluate the performance of the system, blood samples of seven healthy donors were irradiated in vitro with doses from 0–10 Gy and dose-response curves of micronuclei frequencies were generated. To establish the applicability of the system to the detection of high doses, the ratios of mononucleated cells to binucleated cells were determined for three of the donors. All of the dose-response curves generated automatically showed clear dose dependence and good correlation (R2 from 0.914–0.998) with the results of manual scoring. PMID:24502354

  4. Genotoxic Effect in Autoimmune Diseases Evaluated by the Micronucleus Test Assay: Our Experience and Literature Review

    PubMed Central

    Torres-Bugarín, Olivia; Macriz Romero, Nicole; Ramos Ibarra, María Luisa; Flores-García, Aurelio; Valdez Aburto, Penélope; Zavala-Cerna, María Guadalupe

    2015-01-01

    Autoimmune diseases (AD) are classified into organ-specific, systemic, and mixed; all forms of AD share a high risk for cancer development. In AD a destructive immune response induced by autoreactive lymphocytes is started and continues with the production of autoantibodies against different targets; furthermore apoptosis failure and loss of balance in oxidative stress as a consequence of local or systemic inflammation are common features seen in AD as well. Micronucleus (MN) assay can be performed in order to evaluate loss of genetic material in a clear, accurate, fast, simple, and minimally invasive test. The MN formation in the cytoplasm of cells that have undergone proliferation is a consequence of DNA fragmentation during mitosis and the appearance of small additional nuclei during interphase. The MN test, widely accepted for in vitro and in vivo genotoxicity research, provides a sensitive marker of genomic damage associated to diverse conditions. In here, we present a review of our work and other published papers concerning genotoxic effect in AD, identified by means of the MN assay, with the aim of proposing this tool as a possible early biomarker for genotoxic damage, which is a consequence of disease progression. Additionally this biomarker could be used for follow-up, to asses genome damage associated to therapies. PMID:26339592

  5. Tirapazamine: hypoxic cytotoxicity and interaction with radiation as assessed by the micronucleus assay.

    PubMed Central

    Shibata, T.; Shibamoto, Y.; Sasai, K.; Oya, N.; Murata, R.; Takagi, T.; Hiraoka, M.; Takahashi, M.; Abe, M.

    1996-01-01

    We investigated the cytotoxicity and the interaction with low-dose radiation (1-4Gy) of tirapazamine by the in vitro cytokinesis-block micronucleus (MN) assay. Murine SCCVII and human melanoma (G-361) cells were treated with tirapazamine under aerobic or hypoxic conditions for 1 h and the MN frequency was determined using cytochalasin-B. The cells were also treated with or without tirapazamine or KU-2285 (hypoxic cell sensitiser) under hypoxic conditions and irradiated with or without reaeration of the cell suspensions. A dose-dependent increase of MN frequency was observed by tirapazamine treatment and the hypoxic toxicity ratio was about 130 for SCCVII and 37 for G-361. The radiation dose-response curves of MN frequency suggested that the interaction of tirapazamine with irradiation appeared to be essentially additive in both cell lines. In contrast, the dose-response curve became steeper by KU-2285 treatment. Combined effects of tirapazamine and irradiation on the hypoxic cells were much higher than the radiation effect on aerobic cells at low doses, while the effects of KU-2285 did not exceed that of aerobic irradiation. In conclusion, tirapazamine appeared to be superior to hypoxic radiosensitisers at clinically relevant doses, not because of aerobic radiosensitisation but because of its potent hypoxic cytotoxicity additive to radiation effect. PMID:8763848

  6. Repeated-dose liver micronucleus test of 4,4'-methylenedianiline using young adult rats.

    PubMed

    Sanada, Hisakazu; Koyama, Naomi; Wako, Yumi; Kawasako, Kazufumi; Hamada, Shuichi

    2015-03-01

    Liver micronucleus (MN) tests using partial hepatectomized rats or juvenile rats have been shown to be useful for the detection of hepatic carcinogens. Moreover, Narumi et al. established the repeated-dose liver MN test using young adult rats for integration into general toxicity. In the present study, in order to examine the usefulness of the repeated-dose liver MN test, we investigated MN induction with a 14 or 28 day treatment protocol using young adult rats treated with 4,4′-methylenedianiline (MDA), a known hepatic carcinogen. MDA dose-dependently induced micronuclei in hepatocytes in 14- and 28-day repeated-dose tests. However, although statistically significant increases in micronuclei were observed in bone marrow cells at two dose levels in the 14-day study, there was no dose response and no increases in micronuclei in the 28-day study. These results indicate that the evaluation of genotoxic effects using hepatocytes is effective in cases where chromosomal aberrations are not clearly detectable in bone marrow cells. Moreover, the repeated-dose liver MN test allows evaluation at a dose below the maximum tolerable dose, which is required for the conventional MN test because micronucleated hepatocytes accumulate. The repeated-dose liver MN test employed in the present study can be integrated into the spectrum of general toxicity tests without further procedural modifications.

  7. Genotoxicity assessment of cobalt chloride in Eisenia hortensis earthworms coelomocytes by comet assay and micronucleus test.

    PubMed

    Ciğerci, İbrahim Hakkı; Ali, Muhammad Muddassir; Kaygısız, Şöhret Yüksek; Liman, Recep

    2016-02-01

    Cobalt and its different compounds are extensively used worldwide and considered as possible environmental pollutant. Earthworms are useful model organism and its different species are used to monitor soil pollution. No study has been found to detect cobalt chloride (CoCl2) genotoxicity in earthworms. So, current study aimed to evaluate CoCl2 induced genotoxicity in Eisenia hortensis earthworms coelomocytes by alkaline comet assay (CA) and micronucleus (MN) test. The earthworms (n = 10 for each group) were exposed to different series of CoCl2 concentrations (100 ppm, 200 ppm, 300 ppm, 400 ppm, 500 ppm, 600 ppm) to find LD50. The LD50 for CoCl2 was found at 226 ppm. Then, doses of LD50/2, LD50 and 2XLD50 for 48 h were used. CA and MN demonstrated the significant increase (P < 0.05) in DNA damage and chromosomal aberrations. Dose dependent relationship was found. Highest DNA damage and chromosomal aberrations were noticed at 2XLD50. The results concluded that CoCl2 induced DNA damage, cytokinesis failure and chromosomal aberrations in E. hortensis earthworms.

  8. Micronucleus test in rodent tissues other than liver or erythrocytes: Report of the IWGT working group.

    PubMed

    Uno, Yoshifumi; Morita, Takeshi; Luijten, Mirjam; Beevers, Carol; Hamada, Shuichi; Itoh, Satoru; Ohyama, Wakako; Takasawa, Hironao

    2015-05-01

    At the 6th International Workshop on Genotoxicity Testing, the liver micronucleus test (MNT) working group briefly discussed the MNT using tissues other than liver/erythrocytes. Many tissues other than liver/erythrocytes have been studied, primarily for research purposes. They have included the colon and intestinal epithelium, skin, spleen, lung, stomach, bladder, buccal mucosa, vagina, and fetal/neonatal tissues. These tissues were chosen because they were target sites of carcinogens, and/or relevant to a specific route of exposure. Recently, there has been particular focus on the gastrointestinal (GI) tract as it is a contact site associated with high exposure following oral gavage. Furthermore GI tumors are observed with high frequency in human populations. A collaborative study of the rat glandular stomach and colon MNT was conducted in conjunction with a collaborative study of the repeated-dose liver MNT. Based on limited data currently available, the rodent MNT using the glandular stomach and/or colon seems to detect genotoxic carcinogens with GI tract target-organ specificity. The working group concluded that the GI tract MNT would be a promising method to examine clastogenicity or aneugenicity of test chemicals in the stomach and/or colon. Further data will be needed to fully establish the methods, and to identify the sensitivity and specificity of the GI tract MNT.

  9. Genotoxic Effect in Autoimmune Diseases Evaluated by the Micronucleus Test Assay: Our Experience and Literature Review.

    PubMed

    Torres-Bugarín, Olivia; Macriz Romero, Nicole; Ramos Ibarra, María Luisa; Flores-García, Aurelio; Valdez Aburto, Penélope; Zavala-Cerna, María Guadalupe

    2015-01-01

    Autoimmune diseases (AD) are classified into organ-specific, systemic, and mixed; all forms of AD share a high risk for cancer development. In AD a destructive immune response induced by autoreactive lymphocytes is started and continues with the production of autoantibodies against different targets; furthermore apoptosis failure and loss of balance in oxidative stress as a consequence of local or systemic inflammation are common features seen in AD as well. Micronucleus (MN) assay can be performed in order to evaluate loss of genetic material in a clear, accurate, fast, simple, and minimally invasive test. The MN formation in the cytoplasm of cells that have undergone proliferation is a consequence of DNA fragmentation during mitosis and the appearance of small additional nuclei during interphase. The MN test, widely accepted for in vitro and in vivo genotoxicity research, provides a sensitive marker of genomic damage associated to diverse conditions. In here, we present a review of our work and other published papers concerning genotoxic effect in AD, identified by means of the MN assay, with the aim of proposing this tool as a possible early biomarker for genotoxic damage, which is a consequence of disease progression. Additionally this biomarker could be used for follow-up, to asses genome damage associated to therapies.

  10. Genotoxic evaluation of Halfenprox using the human peripheral lymphocyte micronucleus assay and the Ames test.

    PubMed

    Akyıl, Dilek; Eren, Yasin; Konuk, Muhsin; Dere, Hatice; Serteser, Ahmet

    2017-04-01

    The genotoxicity and mutagenicity of Halfenprox, a synthetic pyrethroid insecticide and acaricide, was assessed using two standard genotoxicity assays of the Salmonella typhimurium mutagenicity assay (Ames test) and in vitro micronucleus (MN) assay in human peripheral lymphocytes. In the Ames test, Salmonella strains TA98 and TA100 were treated with or without S9 fraction. The doses of Halfenprox were 6.25, 12.5, 25, 50, and 100 μg/plate and test materials were dissolved in DMSO. The concentrations of Halfenprox did not show mutagenic activity on both strains with and without S9 fraction. The MN assay was used to investigate the genotoxic effects of Halfenprox in human peripheral lymphocytes treated with 250, 500, 750, and 1000 μg/ml concentrations of Halfenprox for 24 and 48 h, and at 1000 μg/ml the concentration was significantly increased and the MN formation was compared with the negative control for both treatment periods. In addition, a significant decrease of the nuclear devision index (NDI) values at the higher concentrations of Halfenprox and at both treatment periods was observed.

  11. Influence of counting methodology on erythrocyte ratios in the mouse micronucleus test.

    PubMed

    LeBaron, Matthew J; Schisler, Melissa R; Torous, Dorothea K; Dertinger, Stephen D; Gollapudi, B Bhaskar

    2013-04-01

    The mammalian erythrocyte micronucleus test is widely used to investigate the potential interaction of a test substance with chromosomes or mitotic apparatus of replicating erythroblasts. In addition to the primary endpoint, micronucleated erythrocyte frequency, the proportion of immature erythrocytes is measured to assess the influence of treatment on erythropoiesis. The guideline recommendation for an acceptable limit of the immature erythrocyte fraction of not < 20% of the controls was based on traditional scoring methods that consider RNA content. Flow-based sample analysis (e.g., MicroFlow®) characterizes a subpopulation of RNA-containing reticulocytes (RETs) based on CD71 (transferrin receptor) expression. As CD71+ cells represent a younger cohort of RETs, we hypothesized that this subpopulation may be more responsive than the RNA+ fraction for acute exposures. This study evaluated RET population in the peripheral blood of two strains of mice treated by oral gavage with three clastogens (cyclophosphamide, N-ethyl-N-nitrosourea, and methyl methanesulfonate). Although CD71+ frequencies correlated with RNA-based counts, the relative treatment-related reductions were substantially greater. Accordingly, when using the flow cytometry-based CD71+ values for scoring RETs in an acute treatment design, it is suggested that a target value ≥ 5% CD71+ reticulocytes (i.e., 95% depression in reticulocytes proportion) be considered as acceptable for a valid assay.

  12. Genotoxicity evaluation of carvacrol in rats using a combined micronucleus and comet assay.

    PubMed

    Llana-Ruiz-Cabello, María; Maisanaba, Sara; Puerto, María; Prieto, Ana I; Pichardo, Silvia; Moyano, Rosario; González-Pérez, José A; Cameán, Ana M

    2016-12-01

    Genotoxic data of substances which could be incorporated into food packaging are required by the European Food Safety Authority. Due to its antioxidant and antibacterial properties carvacrol is one of these compounds. This work aims to study for the first time the in vivo genotoxic effects produced in rats orally exposed to 81, 256 or 810 mg cavacrol/kg body weight (bw) at 0, 24 and 45 h. A combination of the micronucleus assay (OECD 474) in bone marrow and the standard (OECD 489) and enzyme-modified comet assay was used to determine the genotoxicity on cells isolated from stomach and liver of exposed animals. In addition, a histopathological study was performed on the assayed tissues, and also in the lungs due to the volatility of carvacrol. Direct analytical pyrolysis was used to search for carvacrol in viscera and to ensure that the compound reaches stomach and liver cells. Results from MN-comet assay revealed that carvacrol (81-810 mg/kg bw) did not induce in vivo genotoxicity or oxidative DNA damage in any of the tissues investigated. Moreover, no histopathological changes were observed. Altogether, these results suggest lack of genotoxicity of carvacrol and therefore its good profile for its potential application as food preservative.

  13. Induction of adaptive response in mice exposed to 900MHz radiofrequency fields: application of micronucleus assay.

    PubMed

    Jiang, Bingcheng; Zong, Chunyan; Zhao, Hua; Ji, Yongxin; Tong, Jian; Cao, Yi

    2013-03-18

    Adult male ICR mice were pre-exposed to non-ionizing radiofrequency fields (RF), 900MHz at 120μW/cm(2) power density for 4h/day for 7 days (adaptation dose, AD) and then subjected to an acute whole body dose of 3Gy γ-radiation (challenge dose, CD). The classical micronucleus (MN) assay was used to determine the extent of genotoxicity in immature erythrocytes in peripheral blood and bone marrow. The data obtained in mice exposed to AD+CD were compared with those exposed to CD alone. The results indicated that in both tissues, the MN indices were similar in un-exposed controls and those exposed to AD alone while a significantly increased MN frequency was observed in mice exposed to CD alone. Exposure of mice to AD+CD resulted in a significant decrease in MN indices compared to those exposed to CD alone. Thus, the data suggested that pre-exposure of mice to non-ionizing RF is capable of 'protecting' the erythrocytes in the blood and bone marrow from genotoxic effects of subsequent γ-radiation. Such protective phenomenon is generally described as 'adaptive response' (AR) and is well documented in human and animal cells which were pre-exposed to very low doses of ionizing radiation. It is interesting to observe AR being induced by non-ionizing RF.

  14. Inhibitory effects of Enteromorpha linza polysaccharide on micronucleus of Allium sativum root cells.

    PubMed

    Zhang, Zhongshan; Wang, Xiaomei; Li, Jingfen; Liu, Chongbin; Zhang, Quanbin

    2016-06-01

    In this study, the antimutagenic function of the polysaccharide from Enteromorpha linza with the micronucleus test of Allium sativum root cells induced by sulfur dioxide and ultraviolet was studied. The concentration-effect relation of the two inducers was firstly evaluated. The results showed that an increase of genotoxicity damage was demonstrated and micronuclei frequency induced by sulfur dioxide and ultraviolet displayed dose dependent increases. All the doses of polysaccharide did affect the micronuclei frequency formation compared with the negative control. And also, the significant increase in inhibition rate of micronuclei frequency was observed with the increase of the dose of polysaccharide. It was showed maximum inhibition of micronuclei frequency cells (71.74% and 66.70%) at a concentration of 200g/mL in three experiments. The low molecular weight polysaccharide showed higher inhibition rate than raw polysaccharide at the higher concentration (50g/mL) in the absence of sulfur dioxide and ultraviolet. It was confirmed to be a good mutant inhibitor.

  15. Application of Tradescantia micronucleus assay for in-situ evaluation of potential genetic hazards from exposure to chemicals at a wood-preserving site

    SciTech Connect

    Sandhu, S.S.; Gill, B.S.; Casto, B.C.; Rice, J.W.

    1991-01-01

    In situ evaluation of biological hazards from wood preserving chemicals at a hazardous waste site using the Tradescantia micronucleus assay (Trad-MCN) is reported in the study. The chemical analysis of soil samples from the site showed high contamination with arsenic (1,292 mg/kg), chromium (1,444 mg/kg) and copper (924 mg/kg) on the surface of the drip area where wood was allowed to dry after the treatment. Exposure of Tradescantia plants grown within or adjacent to the drip area showed significantly (P=0.05) higher frequencies of micronuclei when compared to plants grown in nearby control plots. After remediation, the levels of arsenic, chromium, and copper were substantially reduced and concomitantly no genotoxic activity was observed in plants grown on-site or in plants exposed in the laboratory to a slurry of soil samples from the site. The results from the pilot study show that simple plant assays such as Trad-MCN can be used as a sentinel for environmental contamination and to assess the efficacy of clean-up efforts.

  16. Evaluation of in vivo genotoxicity by thioacetamide in a 28-day repeated-dose liver micronucleus assay using male young adult rats.

    PubMed

    Sui, Hajime; Matsumoto, Hirotaka; Wako, Yumi; Kawasako, Kazufumi

    2015-03-01

    The repeated-dose liver micronucleus (RDLMN) assay has the potential to detect liver carcinogens and can be integrated into general toxicological studies. In this study, thioacetamide (TAA) was tested in 14- and 28-day RDLMN assays to assess the performance of the assay. The test substance, TAA, was administered orally to 6-week-old male Crl:CD (SD) rats once daily for 14 or 28 days at a dosage of 5, 10 or 20mg/kg/day. Hepatocytes were collected approximately 24h after the last TAA administration, and the incidence of micronuclei was assessed. In this study, bone marrow micronucleus assays were also conducted in the same animals. The 14- and 28-day RDLMN assays indicated that none of the TAA dosages significantly increased the proportion of micronucleated hepatocytes. Bone marrow micronucleus assays with TAA also provided negative results. It is known that TAA is a liver carcinogen in mice and rats. In the previous genotoxic studies, the Ames test and the chromosomal aberration test using CHL/IU cells have yielded negative results [1-4]. The liver micronucleus assay using young adult rats singly dosed with TAA (75 and 150mg/kg) also produced negative results [5]. TAA gave positive results only in the mouse bone marrow micronucleus assays [6,7].

  17. HUman MicroNucleus project: international database comparison for results with the cytokinesis-block micronucleus assay in human lymphocytes: I. Effect of laboratory protocol, scoring criteria, and host factors on the frequency of micronuclei.

    PubMed

    Bonassi, S; Fenech, M; Lando, C; Lin, Y P; Ceppi, M; Chang, W P; Holland, N; Kirsch-Volders, M; Zeiger, E; Ban, S; Barale, R; Bigatti, M P; Bolognesi, C; Jia, C; Di Giorgio, M; Ferguson, L R; Fucic, A; Lima, O G; Hrelia, P; Krishnaja, A P; Lee, T K; Migliore, L; Mikhalevich, L; Mirkova, E; Mosesso, P; Müller, W U; Odagiri, Y; Scarffi, M R; Szabova, E; Vorobtsova, I; Vral, A; Zijno, A

    2001-01-01

    Micronucleus (MN) expression in peripheral blood lymphocytes is well established as a standard method for monitoring chromosome damage in human populations. The first results of an analysis of pooled data from laboratories using the cytokinesis-block micronucleus (CBMN) assay and participating in the HUMN (HUman MicroNucleus project) international collaborative study are presented. The effects of laboratory protocol, scoring criteria, and host factors on baseline micronucleated binucleate cell (MNC) frequency are evaluated, and a reference range of "normal" values against which future studies may be compared is provided. Primary data from historical records were submitted by 25 laboratories distributed in 16 countries. This resulted in a database of nearly 7000 subjects. Potentially significant differences were present in the methods used by participating laboratories, such as in the type of culture medium, the concentration of cytochalasin-B, the percentage of fetal calf serum, and in the culture method. Differences in criteria for scoring micronuclei were also evident. The overall median MNC frequency in nonexposed (i.e., normal) subjects was 6.5 per thousand and the interquartile range was between 3 and 12 per thousand. An increase in MNC frequency with age was evident in all but two laboratories. The effect of gender, although not so evident in all databases, was also present, with females having a 19% higher level of MNC frequency (95% confidence interval: 14-24%). Statistical analyses were performed using random-effects models for correlated data. Our best model, which included exposure to genotoxic factors, host factors, methods, and scoring criteria, explained 75% of the total variance, with the largest contribution attributable to laboratory methods.

  18. Evaluation of a repeated dose liver micronucleus assay in rats treated with two genotoxic hepatocarcinogens, dimethylnitrosamine and 2-acetylaminofluorene: the possibility of integrating micronucleus tests with multiple tissues into a repeated dose general toxicity study.

    PubMed

    Takashima, Rie; Takasawa, Hironao; Kawasako, Kazufumi; Ohyama, Wakako; Okada, Emiko; Narumi, Kazunori; Fujiishi, Yohei; Wako, Yumi; Yasunaga, Katsuaki; Hattori, Akiko; Kawabata, Masayoshi; Nakadate, Kiyoko; Nakagawa, Munehiro; Hamada, Shuichi

    2015-03-01

    As part of a collaborative study by the Collaborative Study Group for Micronucleus Test (CSGMT) of the Mammalian Mutagenicity Study Group (MMS) in the Japanese Environmental Mutagen Society (JEMS), the present study evaluated the effectiveness of the repeated dose liver micronucleus (RDLMN) assay. Two genotoxic hepatocarcinogens, dimethylnitrosamine (DMN) and 2-acetylaminofluorene (2-AAF), were administered orally to male rats (6 weeks old at the initial dosing) once daily for 14 and 28 days to evaluate the micronucleus (MN) inducibility in the liver. In addition, these chemicals were evaluated for MN inducibility in the bone marrow (BM) and gastrointestinal (GI) tract, i.e. glandular stomach and colon of the same animals used in the RDLMN assay. As a result, both chemicals produced positive results in the liver, although a weak positive response was given by 2-AAF. DMN gave negative results in the tissues other than the liver. 2-AAF produced positive responses in the BM and glandular stomach, and a prominent response was particularly observed in the glandular stomach, which is directly exposed to the test chemicals by gavage. The present results suggest that the RDLMN assay is a useful method for detecting genotoxic hepatocarcinogens, and that it is especially effective for evaluating test chemicals, such as DMN, undetectable by the BM and GI tract MN assay. Moreover, the results in this investigation indicate that the use of multiple tissues in the study integrating the MN tests is more effective than using a single tissue, for detection of the MN induction produced by chemical exposure to rats, and helps to determine the characteristics of the test chemicals.

  19. Assessment of the genotoxicity of trichloroethylene in the in vivo micronucleus assay by inhalation exposure.

    PubMed

    Wilmer, J W; Spencer, P J; Ball, N; Bus, J S

    2014-05-01

    The in vivo genotoxic potential of trichloroethylene (TCE) was evaluated by examining the incidence of micronucleated polychromatic erythrocytes (MN-PCEs) in the bone marrow. Groups of male CD rats were exposed by inhalation to targeted concentrations of 0 (negative control), 50, 500, 2500 or 5000 ppm for 6 consecutive hours on a single day. The exposure concentrations were selected to overlap those employed by a published study that reported a 2- to 3-fold increase in the frequency of micronuclei in male rats following a single inhalation exposure to 5, 500 and 5000 ppm TCE for 6h but not following repeated exposure to similar concentrations. In addition, any treatment-related findings were assessed in the context of potential TCE-induced hypothermia. Clinical signs consistent with marked TCE-induced sedation were observed in rats exposed to 5000 ppm and subsequently three rats died prior to the end of the 6h exposure period. No remarkable changes in body temperature were observed in surviving animals monitored with transponders before and after exposures. There were no statistically significant increases in the frequencies of MN-PCEs in groups treated with the test material as compared to the negative controls. The positive control animals showed a significant increase in the frequency of MN-PCEs and a decrease in the relative proportion of PCEs among erythrocytes as compared to the negative control animals. There were no statistically significant differences in the per cent PCEs in groups treated with the test material. As no increase in the incidence of micronuclei was observed in any of the TCE exposure groups, kinetochore analyses were not performed. Under the experimental conditions used, TCE was considered to be negative in the rat bone marrow micronucleus test.

  20. Effects of dietary boron on cervical cytopathology and on micronucleus frequency in exfoliated buccal cells.

    PubMed

    Korkmaz, Mehmet; Uzgören, Engin; Bakirdere, Sezgin; Aydin, Firat; Ataman, O Yavuz

    2007-02-01

    Recent evidence indicates that boron and borates may have anticarcinogenic properties. In this study, we have investigated the incidence of adverse cytological findings in cervical smears and the micronucleus (MN) frequency in women living in boron-rich and boron-poor regions. Cervical smears were prepared from 1059 women with low socioeconomic status; 472 of the women lived in relatively boron-rich rural areas, while 587 lived in relatively boron-poor regions. The average and standard deviation values for the age of the women screened with the cervical Pap smear test were 41.55 +/- 8.38. The mean dietary intake of boron was 8.41 mg/day for women from the boron-rich regions, and 1.26 mg/day for women living in the boron-poor regions (P < 0.0001). Women from the boron-rich regions had no cytopathological indications of cervical cancer, while there were cytopathological findings for 15 women from the boron-poor areas (chi(2) = 10.473, P < 0.05). Sixty women, 30 from each region, were chosen for evaluating MN frequencies in exfoliated buccal cells. MN frequencies for women from the boron-rich and boron-poor regions were not significantly different (t = -0.294, P > 0.05). Also, there were no significant correlations between age and MN frequency for women from both the boron-rich (r = 0.133, P = 0.48, P > 0.05) and boron-poor (r = -0.033, P = 0.861, P > 0.05) regions. The results suggest that ingestion of boron in the drinking water decreases the incidence of cervical cancer-related histopathological findings. There was no correlation between the pathological findings from the cervical smears and buccal cell MN frequency suggesting that the two study populations were exposed equally to gentotoxic agents. Nonetheless, cervical cancer-related histopathological findings should be validated by other researchers.

  1. Dose-response relationship of temozolomide, determined by the Pig-a, comet, and micronucleus assay.

    PubMed

    Guérard, M; Johnson, G; Dertinger, S; Duran-Pacheco, G; Funk, J; Zeller, A

    2017-02-15

    Temozolomide (TMZ), a monofunctional alkylating agent, was selected as a model compound to determine its quantitative genotoxic dose-response relationship in different tissues (blood, liver, and jejunum) and endpoints [Pig-a-, comet-, and micronucleus assay (MNT)] in male rats. TMZ was administered p.o. over 5 consecutive days (day 1-5), followed by a treatment-free period of 50 days (day 6-56) and a final administration prior to necropsy (day 57-59). TMZ showed a dose-dependent increase in DNA damage in all interrogated endpoints. A statistically significant increase in Pig-a mutant phenotypes was observed on day 44 starting at 7.5 mg/kg/day for mutant reticulocytes (for RET(CD59-)) and at 3.75 mg/kg/day for mutant red blood cells (RBC(CD59-)), respectively. In addition, a statistically significant increase in cytogenetic damage, as measured by micronucleated reticulocytes, was observed starting at 3.75 mg/kg/day on day 3 and 1.5 mg/kg/day on day 59. DNA strand breaks, as detected by the comet assay, showed a dose-dependent and statistically significant increase in liver, blood, and jejunum starting at doses of 3.75, 3.75, and 7.5 mg/kg/day, respectively. The dose-response relationships of the Pig-a, MNT, and comet data were analyzed for possible points of departure (PoD) using the benchmark-dose (BMD) software PROAST with different critical effect sizes (CES) (BMD0.1, BMD0.5, BMD1, and BMD1SD). Overall, PoD values show a high concordance between different tissues and endpoints, underlining the suitability of this experimental design to explore quantitative dose-response relationships in a variety of different tissues and endpoints, while minimizing animal use.

  2. Statistical analysis of the hen's egg test for micronucleus induction (HET-MN assay).

    PubMed

    Hothorn, Ludwig A; Reisinger, Kerstin; Wolf, Thorsten; Poth, Albrecht; Fieblinger, Dagmar; Liebsch, Manfred; Pirow, Ralph

    2013-09-18

    The HET-MN assay (hen's egg test for micronucleus induction) is different from other in vitro genotoxicity assays in that it includes toxicologically important features such as absorption, distribution, metabolic activation, and excretion of the test compound. As a promising follow-up to complement existing in vitro test batteries for genotoxicity, the HET-MN is currently undergoing a formal validation. To optimize the validation, the present study describes a critical analysis of previously obtained HET-MN data to check the experimental design and to identify the most appropriate statistical procedure to evaluate treatment effects. Six statistical challenges (I-VI) of general relevance were identified, and remedies were provided which can be transferred to similarly designed test methods: a Williams-type trend test is proposed for overdispersed counts (II) by means of a square-root transformation which is robust for small sample sizes (I), variance heterogeneity (III), and possible downturn effects at high doses (IV). Due to near-to-zero or even zero-count data occurring in the negative control (V), a conditional comparison of the treatment groups against the mean of the historical controls (VI) instead of the concurrent control was proposed, which is in accordance with US-FDA recommendations. For the modified Williams-type tests, the power can be estimated depending on the magnitude and shape of the trend, the number of dose groups, and the magnitude of the MN counts in the negative control. The experimental design used previously (i.e. six eggs per dose group, scoring of 1000 cells per egg) was confirmed. The proposed approaches are easily available in the statistical computing environment R, and the corresponding R-codes are provided.

  3. Clinical application of micronucleus test in exfoliated buccal cells: A systematic review and metanalysis.

    PubMed

    Bolognesi, Claudia; Bonassi, Stefano; Knasmueller, Siegfried; Fenech, Michael; Bruzzone, Marco; Lando, Cecilia; Ceppi, Marcello

    2015-01-01

    The micronucleus assay in uncultured exfoliated buccal mucosa cells, involving minimally invasive sampling, was successfully applied to evaluate inhalation and local exposure to genotoxic agents, impact of nutrition and lifestyle factors. The potential use of the assay in clinics to monitor the development of local oral lesions and as an early biomarker for tumors and different chronic disorders was also investigated. A systematic review of the literature was carried out focusing on the clinical application of the assay. The literature search updated to January 2015 allowed to retrieve 42 eligible articles. Fifty three percent of investigations are related to oral, head and neck cancer, and premalignant oral diseases. Our analysis evidences a potential usefulness of the MN assay applied in buccal exfoliated cells in the prescreening and in the follow up of precancerous oral lesions. A significant excess of MN, in patients compared with matched controls was observed for subgroups of oral and neck cancer (meta-MR of 2.40, 95% CI: 2.02-2.85) and leukoplakia (meta-MR 1.88, 95% CI: 1.51-2.35). The meta-analysis of studies available on other tumors (meta-MR 2.00; 95% CI:1.66-2.41) indicates that the MN frequency in buccal cells could reflect the chromosomal instability of other organs. Increased MN frequency was also observed in small size studies on patients with chronic diseases, with Alzheimer's disease and with Down syndrome. The application of the cytome approach providing information of genotoxic, cytotoxic and cytostatic effects is suggestive of the possibility of an improvement in the predictive value of the assay and this deserves further investigations.

  4. Study design and statistical analysis of data in human population studies with the micronucleus assay.

    PubMed

    Ceppi, Marcello; Gallo, Fabio; Bonassi, Stefano

    2011-01-01

    The most common study design performed in population studies based on the micronucleus (MN) assay, is the cross-sectional study, which is largely performed to evaluate the DNA damaging effects of exposure to genotoxic agents in the workplace, in the environment, as well as from diet or lifestyle factors. Sample size is still a critical issue in the design of MN studies since most recent studies considering gene-environment interaction, often require a sample size of several hundred subjects, which is in many cases difficult to achieve. The control of confounding is another major threat to the validity of causal inference. The most popular confounders considered in population studies using MN are age, gender and smoking habit. Extensive attention is given to the assessment of effect modification, given the increasing inclusion of biomarkers of genetic susceptibility in the study design. Selected issues concerning the statistical treatment of data have been addressed in this mini-review, starting from data description, which is a critical step of statistical analysis, since it allows to detect possible errors in the dataset to be analysed and to check the validity of assumptions required for more complex analyses. Basic issues dealing with statistical analysis of biomarkers are extensively evaluated, including methods to explore the dose-response relationship among two continuous variables and inferential analysis. A critical approach to the use of parametric and non-parametric methods is presented, before addressing the issue of most suitable multivariate models to fit MN data. In the last decade, the quality of statistical analysis of MN data has certainly evolved, although even nowadays only a small number of studies apply the Poisson model, which is the most suitable method for the analysis of MN data.

  5. A combination of in vitro comet assay and micronucleus test using human lymphoblastoid TK6 cells.

    PubMed

    Kimura, Aoi; Miyata, Atsuro; Honma, Masamitsu

    2013-09-01

    The comet assay has been widely used as a genotoxicity test for detecting primary DNA damage in individual cells. The micronucleus (MN) test is also a well-established assay for detecting clastogenicity and aneugenicity. A combination of the comet assay (COM) and MN test is capable of detecting a variety of genotoxic potentials as an in vitro screening system. Although the in vitro MN test has a robust protocol and Organisation for Economic Co-operation and Development (OECD) test guideline, the in vitro COM does not. To establish a robust protocol for the COM and to compare its sensitivity with that of the MN, we conducted COM and MN concurrently for five genotoxic agents (ethyl methanesulfonate, methyl methanesulfonate, hydrogen peroxide, gamma-rays and mitomycin C) and one non-genotoxic agent (triton X-100), using human lymphoblastoid TK6 cells. Relative cell count (RCC), relative population doubling (RPD), relative increase in cell count (RICC) and relative cell viability determined by trypan blue dye-exclusion assay (TBDE) were employed as cytotoxic measurements. However, the relative cell viability determined by TBDE just after the treatment was not an appropriate parameter of cytotoxicity for the genotoxic agents because it remained constant even at the highest doses, which showed severe cytotoxicity by RCC, RPD and RICC. The results of the COM showed qualitative agreement (positive or negative) with those of the MN except for mitomycin C, which is an interstrand cross-linker. The COM always required higher doses than the MN to detect the genotoxic potential of the genotoxic agents under the test conditions applied here. The doses that induced a comet tail always yielded <50% RICC, and do not accord to the OECD test guideline for MN because of their high cytotoxicity. These results are helpful for interpreting the results of the COM and MN in in vitro genotoxic hazard assessments. Further investigation is required to standardise the COM.

  6. Evaluation of the mutagenicity and antimutagenicity of Ziziphus joazeiro Mart. bark in the micronucleus assay

    PubMed Central

    Boriollo, Marcelo Fabiano Gomes; Resende, Marielly Reis; da Silva, Thaísla Andrielle; Públio, Juliana Yoshida; Souza, Luiz Silva; Dias, Carlos Tadeu dos Santos; de Mello Silva Oliveira, Nelma; Fiorini, João Evangelista

    2014-01-01

    The aim of this study was to evaluate the mutagenicity (clastogenicity/aneugenicity) of a glycolic extract of Ziziphus joazeiro bark (GEZJ) by the micronucleus assay in mice bone marrow. Antimutagenic activity was also assessed using treatments associated with GEZJ and doxorubicin (DXR). Mice were evaluated 24–48 h after exposure to positive (N-nitroso-N-ethylurea, NEU - 50 mg.kg−1 and DXR - 5 mg.kg−1) and negative (150 mM NaCl) controls, as well as treatment with GEZJ (0.5–2 g.kg−1), GEZJ (2 g.kg−1) + NEU and GEZJ (2 g.kg−1) + DXR. There were no significant differences in the frequencies of micronucleated polychromatic erythrocytes in mice treated with GEJZ and GEJZ + DXR compared to the negative controls, indicating that GEZJ was not mutagenic. Analysis of the polychromatic:normochromatic erythrocyte ratio revealed significant differences in the responses to doses of 0.5 g.kg−1 and 1–2 g.kg−1 and the positive control (NEU). These results indicated no systemic toxicity and moderate toxicity at lower and higher doses of GEZJ. The lack of mutagenicity and systemic toxicity in the antimutagenic assays, especially for treatment with GEZJ + DXR, suggested that phytochemical compounds in Z. joazeiro bark attenuated DXR-induced mutagenicity and the moderate systemic toxicity of a high dose of Z. joazeiro bark (2 g.kg−1). Further studies on the genotoxicity of Z. joazeiro extracts are necessary to establish the possible health risk in humans and to determine the potential as a chemopreventive agent for therapeutic use. PMID:25071409

  7. Multicolour FISH analysis of ionising radiation induced micronucleus formation in human lymphocytes

    PubMed Central

    Balajee, Adayabalam S.; Bertucci, Antonella; Taveras, Maria; Brenner, David J.

    2014-01-01

    Micronucleation of chromosomal DNA is an effective indicator of DNA damage and micronucleus (MN) analysis is a valuable tool for radiation biodosimetry studies. To gain a comprehensive knowledge of micronucleation process after ionising radiation (IR) exposure, whole genome-wide chromosome analysis is desirable. With this objective, multicolour fluorescence in situ hybridization (M-FISH) technique was utilised in the present study to characterise the chromosome content of spontaneous and IR-induced micronuclei in three human donors. M-FISH analysis revealed a radiation dose-dependant increase in the number of micronuclei with multi-chromosome material above 2 Gy and as many as 3–6 multicolour signals were detected in micronuclei after high γ-rays radiation doses (5–10 Gy). Involvement of each human chromosome material was more frequently detected in multicoloured micronuclei than in single-coloured micronuclei at high radiation doses (>2 Gy). Observation of dose-dependant increase in the MN frequency with multi-chromosome material may be due to misrepair of DNA double-strand breaks involving multiple chromosomes leading to asymmetric dicentric or ring chromosomes and acentric fragments. Chromosomes belonging to groups A (1, 2 and 3) and B (4 and 5) were frequently detected in 35–45% of the total micronuclei either as single entities or in combination with other chromosomes. Among the A and B groups, chromosome 1 material was consistently detected at high MN frequencies after radiation exposure in all the donors. Additionally, chromosomes 13 and 19 were more frequently observed in micronuclei than the expected frequency based on DNA content. Our whole genome approach utilising the M-FISH technique revealed that MN formation at high radiation doses might be complex involving multiple chromosome fragments. Understanding the fate and biological consequences of these multi-chromosome-containing micronuclei may provide key molecular insights for some aspects of IR

  8. Lack of micronucleus induction activity of ethyl tertiary-butyl ether in the bone marrow of F344 rats by sub-chronic drinking-water treatment, inhalation exposure, or acute intraperitoneal injection.

    PubMed

    Noguchi, Tadashi; Kamigaito, Tomoyuki; Katagiri, Taku; Kondou, Hitomi; Yamazaki, Kazunori; Aiso, Shigetoshi; Nishizawa, Tomoshi; Nagano, Kasuke; Fukushima, Shoji

    2013-01-01

    Ethyl tertiary-butyl ether (ETBE) is an oxygenated gasoline additive synthesized from ethanol and isobutene that is used to reduce CO2 emissions. To support the Kyoto Protocol, the production of ETBE has undergone a marked increase. Previous reports have indicated that exposure to ETBE or methyl tertiary-butyl ether resulted in liver and kidney tumors in rats and/or mice. These reports raise concern about the effects of human exposure being brought about by the increased use of ETBE. The present study was conducted to evaluate the genotoxicity of ETBE using micronucleus induction of polychromatic erythrocytes in the bone marrow of male and female rats treated with ETBE in the drinking-water at concentrations of 0, 1,600, 4,000 or 10,000 ppm or exposed to ETBE vapor at 0, 500, 1,500 or 5,000 ppm for 13 weeks. There were no significant increases in micronucleus induction in either the drinking water-administered or inhalation-administered groups at any concentration of ETBE; although, in both groups red blood cells and hemoglobin concentration were slightly reduced in the peripheral blood in rats administered the highest concentration of ETBE. In addition, two consecutive daily intraperitoneal injections of ETBE at doses of 0, 250, 500 or 1,000 mg/kg did not increase the frequency of micronucleated bone marrow cells in either sex; all rats receiving intraperitoneal injections of ETBE at a dose of 2,000 mg/kg died after treatment day 1. These data suggest that ETBE is not genotoxic in vivo.

  9. Absence of genotoxicity of potato alkaloids alpha-chaconine, alpha-solanine and solanidine in the Ames Salmonella and adult and foetal erythrocyte micronucleus assays.

    PubMed

    Friedman, M; Henika, P R

    1992-08-01

    To assess whether reported toxicities of potato-derived glycoalkaloids could be the result of interactions with cellular DNA, the genotoxic effects of alpha-solanine, alpha-chaconine and solanidine were studied, using the Ames test (Salmonella strains TA98 and TA100), the mouse peripheral blood micronucleus test and the mouse transplacental micronucleus test. The Ames test for mutagenicity with alpha-solanine was weakly positive in TA100 with S-9 activation (29 revertants per millimole per plate). However, pooled data from duplicate tests gave a negative effect. Pooled data from two experiments with alpha-chaconine gave a weak positive response in TA98 without microsomes (17 revertants per millimole per plate). The micronucleus tests for clastogenicity using male mouse and foetal blood were negative. The absence of mutagenicity and clastogenicity suggests lack of damage to intracellular DNA for potato alkaloid toxicity.

  10. Comparative genotoxicity of nanosilver in human liver HepG2 and colon Caco2 cells evaluated by a flow cytometric in vitro micronucleus assay.

    PubMed

    Sahu, Saura C; Njoroge, Joyce; Bryce, Steven M; Yourick, Jeffrey J; Sprando, Robert L

    2014-11-01

    Two widely used in vitro cell culture models, human liver HepG2 cells and human colon Caco2 cells, and flow cytometry techniques were evaluated as tools for rapid screening of potential genotoxicity of food-related nanosilver. Comparative genotoxic potential of 20 nm silver was evaluated in HepG2 and Caco2 cell cultures by a flow cytometric-based in vitro micronucleus assay. The nanosilver, characterized by the dynamic light scattering, transmission electron microscopy and inductively coupled plasma-mass spectrometry analysis, showed no agglomeration of the silver nanoparticles. The inductively coupled plasma-mass spectrometry and transmission electron microscopy analysis demonstrated the uptake of 20 nm silver by both cell types. The 20 nm silver exposure of HepG2 cells increased the concentration-dependent micronucleus formation sevenfold at 10 µg ml(-1) concentration in attached cell conditions and 1.3-fold in cell suspension conditions compared to the vehicle controls. However, compared to the vehicle controls, the 20 nm silver exposure of Caco2 cells increased the micronucleus formation 1.2-fold at a concentration of 10 µg ml(-1) both in the attached cell conditions as well as in the cell suspension conditions. Our results of flow cytometric in vitro micronucleus assay appear to suggest that the HepG2 cells are more susceptible to the nanosilver-induced micronucleus formation than the Caco2 cells compared to the vehicle controls. However, our results also suggest that the widely used in vitro models, HepG2 and Caco2 cells and the flow cytometric in vitro micronucleus assay are valuable tools for the rapid screening of genotoxic potential of nanosilver and deserve more careful evaluation.

  11. 3-Nitrobenzanthrone (3-NBA) induced micronucleus formation and DNA damage in human hepatoma (HepG2) cells.

    PubMed

    Lamy, Evelyn; Kassie, Fekadu; Gminski, Richard; Schmeiser, Heinz H; Mersch-Sundermann, Volker

    2004-01-15

    3-Nitrobenzanthrone (3-NBA), identified in diesel exhaust and in airborne particulate matter, is a potent mutagen in Salmonella, induces micronuclei formation in mice and in human cells and DNA adducts in rats. In the present study, we investigated the genotoxic potency of 3-NBA in human HepG2 cells using the micronucleus (MN) assay and the single cell gel electrophoresis (SCGE). 3-NBA caused a genotoxic effect at concentrations > or =12 nM in both assays. In the micronucleus assay, we found 98.7+/-10.3 MN/1000 BNC at a concentration of 100 nM 3-NBA in comparison to 27.3+/-0.6 MN/1000 BNC with the negative control. At the same concentration, the DNA-migration (SCGE) showed an Olive tail moment (OTM) of 2.7+/-0.45 and %DNA in the tail of 8.28+/-0.76; OTM and %DNA in the tail of cells treated with the negative control were 0.73+/-0.08 and 2.81+/-0.30, respectively. The results are discussed under consideration of former studies.

  12. Genotoxic potential generated by biomass burning in the Brazilian Legal Amazon by Tradescantia micronucleus bioassay: a toxicity assessment study

    PubMed Central

    2011-01-01

    Background The Brazilian Amazon has suffered impacts from non-sustainable economic development, especially owing to the expansion of agricultural commodities into forest areas. The Tangará da Serra region, located in the southern of the Legal Amazon, is characterized by non-mechanized sugar cane production. In addition, it lies on the dispersion path of the pollution plume generated by biomass burning. The aim of this study was to assess the genotoxic potential of the atmosphere in the Tangará da Serra region, using Tradescantia pallida as in situ bioindicator. Methods The study was conducted during the dry and rainy seasons, where the plants were exposed to two types of exposure, active and passive. Results The results showed that in all the sampling seasons, irrespective of exposure type, there was an increase in micronucleus frequency, compared to control and that it was statistically significant in the dry season. A strong and significant relationship was also observed between the increase in micronucleus incidence and the rise in fine particulate matter, and hospital morbidity from respiratory diseases in children. Conclusions Based on the results, we demonstrated that pollutants generated by biomass burning in the Brazilian Amazon can induce genetic damage in test plants that was more prominent during dry season, and correlated with the level of particulates and elevated respiratory morbidity. PMID:21575274

  13. Genotoxic evaluation of the River Paranaíba hydrographic basin in Monte Carmelo, MG, Brazil, by the Tradescantia micronucleus

    PubMed Central

    Campos, Carlos F.; Pereira, Boscolli B.; de Campos-Junior, Edimar O.; Sousa, Eduardo F.; Souto, Henrique N.; Morelli, Sandra

    2015-01-01

    Abstract Pollutants have adverse effects on human health and on other organisms that inhabit or use water resources. The aim of the present study was to assess the environmental quality of three watercourses in Monte Carmelo, MG, Brazil, using the micronucleus test on Tradescantia. For each treatment, 15 plants were exposed to water samples for 24 h. The control group was exposed to formaldehyde (0.2%) and the negative control to Hoagland solution. Subsequently the plants were placed in Hoagland solution for 24 h to recover. Cells were stained with 2% acetic carmine and examined by light microscopy. Three hundred tetrads were analyzed per slide. The frequency of genotoxic alterations was expressed as the number of micronuclei per 100 tetrads, and the groups were compared by ANOVA. At all sample sites for each watercourse significant genotoxicity indices were observed. The results suggest that in the Mumbuca creek, the current situation of effluent discharge should be reconsidered by the municipal environmental authorities. The increase in micronucleus frequency denoted for water samples of the Mumbuca creek, Lambari river and Perdizes river emphasizes the need to adopt environmental vigilance strategies, such as biological monitoring. PMID:26692158

  14. Genotoxicity testing of three monohaloacetic acids in TK6 cells using the cytokinesis-block micronucleus assay.

    PubMed

    Liviac, Danae; Creus, Amadeu; Marcos, Ricard

    2010-09-01

    Chemical disinfection of water generates harmful chemical compounds, known as disinfection by-products (DBPs). One class of DBPs is constituted by haloacetic acids (HAAs), the second major group in prevalence (after trihalomethanes) detected in finished drinking water. In this article, we report the results obtained in the evaluation of the chromosome damage induced by three monohaloacetic acids, namely iodoacetic acid (IAA), bromoacetic acid (BAA) and chloroacetic acid (CAA). To evaluate the induction of chromosome damage, we used the cytokinesis-block micronucleus test that measures the ability of genotoxic agents to induce both clastogenic and/or aneugenic effects. No previous data exist on the effects of these compounds on human chromosomes. We tested five doses of each HAA, in addition to the negative and positive controls. The highest dose tested for each HAA was that immediately lower than the dose producing total cytotoxicity. Our results show that none of the three HAAs tested was able to increase significantly the frequency of micronucleus in binucleated TK6 cells, the rank order in decreasing cytotoxicity was IAA > BAA > CAA.

  15. TIF1 Activates the Intra-S-Phase Checkpoint Response in the Diploid Micronucleus and Amitotic Polyploid Macronucleus of Tetrahymena

    PubMed Central

    Yakisich, J. Sebastian; Sandoval, Pamela Y.; Morrison, Tara L.

    2006-01-01

    The ribosomal DNA origin binding protein Tif1p regulates the timing of rDNA replication and is required globally for proper S-phase progression and division of the Tetrahymena thermophila macronucleus. Here, we show that Tif1p safeguards chromosomes from DNA damage in the mitotic micronucleus and amitotic macronucleus. TIF1p localization is dynamically regulated as it moves into the micro- and macronucleus during the respective S phases. TIF1 disruption mutants are hypersensitive to hydroxyurea and methylmethanesulfonate, inducers of DNA damage and intra-S-phase checkpoint arrest in all examined eukaryotes. TIF1 mutants incur double-strand breaks in the absence of exogenous genotoxic stress, destabilizing all five micronuclear chromosomes. Wild-type Tetrahymena elicits an intra-S-phase checkpoint response that is induced by hydroxyurea and suppressed by caffeine, an inhibitor of the apical checkpoint kinase ATR/MEC1. In contrast, hydroxyurea-challenged TIF1 mutants fail to arrest in S phase or exhibit caffeine-sensitive Rad51 overexpression, indicating the involvement of TIF1 in checkpoint activation. Although aberrant micro- and macronuclear division occurs in TIF1 mutants and caffeine-treated wild-type cells, TIF1p bears no similarity to ATR or its substrates. We propose that TIF1 and ATR function in the same epistatic pathway to regulate checkpoint responses in the diploid mitotic micronucleus and polyploid amitotic macronucleus. PMID:17005912

  16. ICP-OES and Micronucleus Test to Evaluate Heavy Metal Contamination in Commercially Available Brazilian Herbal Teas.

    PubMed

    Schunk, Priscila Francisca Tschaen; Kalil, Ieda Carneiro; Pimentel-Schmitt, Elisangela Flavia; Lenz, Dominik; de Andrade, Tadeu Uggere; Ribeiro, Juliano Souza; Endringer, Denise Coutinho

    2016-07-01

    Increased tea consumption in combination with intensive pesticide use is generating heavy metal contaminations amongst Brazilian tea consumers, causing health concerns. Inductively coupled plasma optical emission spectrometry (ICP-OES) was applied to quantify minerals and heavy metals such as aluminum, barium, cadmium, lead, cobalt, copper, chromium, tin, manganese, molybdenum, nickel, selenium, silver, thallium, vanadium and zinc in Brazilian chamomile, lemongrass, fennel and yerba mate teas. Teas, purchased in local supermarkets, were prepared using infusion and acid digestion. Higher concentrations of Al were present in all samples. In the digested samples, the Al mean concentration was 2.41 μg g(-1) (sd = 0.72) for fennel and 33.42 μg g(-1) (sd = 17.18) for chamomile, whilst the sample C for chamomile tea presented the highest concentration with 51.62 μg g(-1) (sd = 9.17). The safety relation in decreasing order is fennel, lemongrass, chamomile and yerba mate. Chemometric analyses demonstrated a strong correlation between the elements Cd and Pb in the samples. Yerba mate had the highest amount of metal (100 mg kg(-1)), being the subject of a micronucleus test assay for cytotoxicity. The metals found in Yerba mate did not present cytotoxicity/mutagenicity using the micronucleus test. The inorganic contaminants in teas should have their impact carefully monitored.

  17. Genotoxic evaluation of aspirin eugenol ester using the Ames test and the mouse bone marrow micronucleus assay.

    PubMed

    Li, Jianyong; Kong, Xiaojun; Li, Xiwang; Yang, Yajun; Zhang, Jiyu

    2013-12-01

    Aspirin eugenol ester (AEE) is a promising drug candidate for treatment of inflammation, pain and fever and prevention of cardiovascular diseases with less side effects and it is important to characterize its genotoxicity. In this study, the genotoxicity of AEE was assessed with two standard genotoxicity assays of the Salmonella typhimurium mutagenicity assay (Ames test) and the mouse bone marrow micronucleus assay. In the Ames test, Salmonella strains TA97, TA98, TA100, TA102 and TA1535 were treated with or without the metabolic activation with a S9 fraction from Acroclor-induced rat liver. The doses of AEE were 5 mg/plate, 2.5 mg/plate, 1.25 mg/plate, 0.625 mg/plate and 0.3125 mg/plate, respectively. In the above tested strains, mutagenicity with or without the S-9 mixture was not detected. In the mammalian erythrocyte micronucleus assay, fifty mice were divided into five groups evenly and the AEE dose at 5000 mg/kg, 2500 mg/kg and 1250 mg/kg and the cyclophosphamide dose at 40 mg/kg as a positive control, the 0.5% of CMC-Na as negative control were administered. The results showed that AEE did not induce any significant increase in micronucleated erythrocytes after 24 h (p<0.01). Our results suggested that AEE was non-genotoxic in vivo or in vitro.

  18. Genotoxic investigation of a thiazolidinedione PPARγ agonist using the in vitro micronucleus test and the in vivo homozygotization assay.

    PubMed

    Morais, Janicélle Fernandes; Sant'Anna, Juliane Rocha de; Pereira, Tais Susane; Franco, Claudinéia Conationi da Silva; Mathias, Paulo Cezar de Freitas; de Castro-Prado, Marialba Avezum Alves

    2016-07-01

    Pioglitazone (PTZ) is an oral antidiabetic agent whose anti-cancer properties have been described recently. Since PTZ increases the production of reactive oxygen species in mammalian cells, the aim of current study was to evaluate the cytotoxic, mutagenic and recombinogenic effects of PTZ using respectively the in vitro mitotic index assay and the in vitro mammalian cell micronucleus test in human peripheral lymphocytes, and the in vivo homozygotization assay in Aspergillus nidulans, which detects the loss of heterozygosity due to somatic recombination. Although the lowest PTZ concentrations (4-36 μM) did not show any significant rise in the micronucleus production, the higher PTZ concentration (108 μM) produced a statistically higher number of micronuclei than the negative control and significantly altered the cell-proliferation kinetics, demonstrating the mutagenic and antiproliferative effects of PTZ, respectively. The recombinogenic activity of PTZ, demonstrated here for the first time, was observed at the highest tested concentration (400 μM) through the homozygotization index rates significantly different from the negative control. Taken together, our results show that PTZ is genotoxic at a concentration higher than the therapeutic plasma concentration. This PTZ genotoxicity may be a potential benefit to its previously described antitumour activity.

  19. Biomonitoring of agricultural workers exposed to pesticide mixtures in Guerrero state, Mexico, with comet assay and micronucleus test.

    PubMed

    Carbajal-López, Yolanda; Gómez-Arroyo, Sandra; Villalobos-Pietrini, Rafael; Calderón-Segura, María Elena; Martínez-Arroyo, Amparo

    2016-02-01

    The aim of this study was to evaluate the genotoxic effect of pesticides in exfoliated buccal cells of workers occupationally exposed in Guerrero, Mexico, using the comet assay and the micronucleus test. The study compared 111 agricultural workers in three rural communities (Arcelia 62, Ajuchitlan 13, and Tlapehuala 36), with 60 non-exposed individuals. All the participants were males. The presence of DNA damage was investigated in the exfoliated buccal cells of study participants with the comet assay and the micronucleus (MN) test; comet tail length was evaluated in 100 nuclei and 3000 epithelial cells of each individual, respectively; other nuclear anomalies such as nuclear buds, karyolysis, karyorrhexis, and binucleate cells were also evaluated. Study results revealed that the tail migration of DNA and the frequency of MN increased significantly in the exposed group, which also showed nuclear anomalies associated with cytotoxic or genotoxic effect. No positive correlation was noted between exposure time and tail length and micronuclei frequencies. No significant effect on genetic damage was observed as a result of age, smoking, and alcohol consumption. The MN and comet assay in exfoliated buccal cells are useful and minimally invasive methods for monitoring genetic damage in individuals exposed to pesticides. This study provided valuable data for establishing the possible risk to human health associated with pesticide exposure.

  20. Allium cepa chromosome aberration and micronucleus tests applied to study genotoxicity of extracts from pesticide-treated vegetables and grapes.

    PubMed

    Feretti, D; Zerbini, I; Zani, C; Ceretti, E; Moretti, M; Monarca, S

    2007-06-01

    The Allium cepa assay is an efficient test for chemical screening and in situ monitoring for genotoxicity of environmental contaminants. The test has been used widely to study genotoxicity of many pesticides revealing that these compounds can induce chromosomal aberrations in root meristems of A. cepa. Pesticide residues can be present in fruit and vegetables and represent a risk for human health. The mutagenic and carcinogenic action of herbicides, insecticides and fungicides on experimental animals is well known. Several studies have shown that chronic exposure to low levels of pesticides can cause birth defects and that prenatal exposure is associated with carcinogenicity. This study evaluated the potential application of plant genotoxicity tests for monitoring mutagens in edible vegetables. The presence of pesticides and genotoxic compounds extracted from 21 treated vegetables and eight types of grapes sampled from several markets in Campania, a region in Southern Italy, was monitored concurrently. The extracts were analysed for pesticides by gas chromatography and high-performance liquid chromatography, and for genotoxicity using two plant tests: the micronucleus test and the chromosomal aberration test in A. cepa roots. Thirty-three pesticides were detected, some of which are not approved. Genotoxicity was found in some of the vegetables and grapes tested. Allium cepa tests proved to be sensitive in monitoring genotoxicity in food extracts. The micronucleus test in interphase cells gave a much higher mutagenicity than the chromosomal aberration test in anaphase-telophase cells.

  1. Radioprotective effects of selenium and vitamin-E against 6MV X-rays in human blood lymphocytes by micronucleus assay

    PubMed Central

    Rostami, Aram; Moosavi, Seyed Akbar; Changizi, Vahid; Abbasian Ardakani, Ali

    2016-01-01

    Background: Critical macromolecules of cells such as DNA are in exposure to damage of free radicals that induced from the interaction of ionizing radiation with biological systems. Selenium and vitamin-E are natural compounds that have been shown to be a direct free radical scavenger. The aim of this study was to investigate the radioprotective effect of selenium and vitamin-E separately and synergistically against genotoxicity induced by 6MV x-rays irradiation in blood lymphocytes. Methods: Fifteen volunteers were divided into three groups include A, B and C. These groups were given selenium (800IU), vitamin-E (100mg) and selenium (400IU) + vitamin-E (50mg), respectively. Peripheral blood samples were collected from each group before (0hr) and 1, 2 and 3hr after selenium and vitamin-E administration (separately and synergistically). Then the blood samples were irradiated to 200cGy of 6MV x-rays. After that lymphocyte samples were cultured with mitogenic stimulation to determine the chromosomal aberrations with micronucleus assay in cytokinesis-blocked binucleated cells. Results: The lymphocytes in the blood samples collected at one hr after ingestion selenium and vitamin-E, exposed in vitro to x-rays exhibited a significant decrease in the incidence of micronuclei, compared with control group at 0hr. The maximum protection and decrease in frequency of micronuclei (50%) were observed at one hr after administration of selenium and vitamin-E synergistically. Conclusion: The data suggest that ingestion of selenium and vitamin-E as a radioprotector substance before exposures may reduce genetic damage caused by x-rays irradiation. PMID:27493911

  2. Nongenotoxic effects and a reduction of the DXR-induced genotoxic effects of Helianthus annuus Linné (sunflower) seeds revealed by micronucleus assays in mouse bone marrow

    PubMed Central

    2014-01-01

    Background This research evaluated the genotoxicity of oil and tincture of H. annuus L. seeds using the micronucleus assay in bone marrow of mice. The interaction between these preparations and the genotoxic effects of doxorubicin (DXR) was also analysed (antigenotoxicity test). Methods Experimental groups were evaluated at 24-48 h post treatment with N-Nitroso-N-ethylurea (positive control – NEU), DXR (chemotherapeutic), NaCl (negative control), a sunflower tincture (THALS) and two sources of sunflower oils (POHALS and FOHALS). Antigenotoxic assays were carried out using the sunflower tincture and oils separately and in combination with NUE or DXR. Results For THALS, analysis of the MNPCEs showed no significant differences between treatment doses (250–2,000 mg.Kg-1) and NaCl. A significant reduction in MNPCE was observed when THALS (2,000 mg.Kg-1) was administered in combination with DXR (5 mg.Kg-1). For POHALS or FOHALS, analysis of the MNPCEs also showed no significant differences between treatment doses (250–2,000 mg.Kg-1) and NaCl. However, the combination DXR + POHALS (2,000 mg.Kg-1) or DXR + FOHALS (2,000 mg.Kg-1) not contributed to the MNPCEs reduction. Conclusions This research suggests absence of genotoxicity of THALS, dose-, time- and sex-independent, and its combination with DXR can reduce the genotoxic effects of DXR. POHALS and FOHALS also showed absence of genotoxicity, but their association with DXR showed no antigenotoxic effects. PMID:24694203

  3. The effect of age, gender, diet and lifestyle on DNA damage measured using micronucleus frequency in human peripheral blood lymphocytes.

    PubMed

    Fenech, Michael; Bonassi, Stefano

    2011-01-01

    Micronucleus (MN) frequency in cytokinesis-blocked peripheral blood lymphocytes (PBL) has become one of the best-established biomarkers for studying DNA damage occurring in vivo in humans. The application of this method in population biomonitoring studies requires a deep understanding of how lifestyle and common host variables may influence MN frequency in PBL. In this mini-review, an update is provided on results from studies reporting on the impact of age, gender, diet and lifestyle factors (e.g. exercise, alcohol, smoking and recreational drugs) on this biomarker. Evidence from these studies shows that each of these factors, either in isolation or in combination, can significantly influence MN frequency. Proper control for these factors is required to enable better measurement of the impact of other conditions, such as environmental exposure to genotoxins or a susceptible genetic background, on MN frequency in PBL.

  4. Genotoxicity of occupational exposure to wood dust: Micronucleus frequency and nuclear changes in exfoliated buccal mucosa cells.

    PubMed

    Celik, Ayla; Kanik, Arzu

    2006-12-01

    Occupational exposure to wood dust is associated with the occurrence of nasal cancer. In this study, we investigated micronuclei and nuclear changes (NCs: binucleates, karyorrhexis, karyolysis, and the "broken egg" effect) in exfoliated buccal cells of 20 workers exposed to wood dust and 20 age- and sex-matched controls. Micronucleus frequency and the frequency of each of the NCs were significantly higher for wood workers than controls (P < 0.01). Cigarette smoking was associated with increased frequencies of micronuclei and NCs in the buccal mucosa epithelium cells of both the control and exposed groups. Our findings indicate that buccal cells of wood workers display increased levels of genotoxicity and toxicity, and that these biomarker responses may be related to the increased cancer risk among wood workers.

  5. Determination of genotoxic effects of methidathion alkaline hydrolysis in human lymphocytes using the micronucleus assay and square-wave voltammetry.

    PubMed

    Stivaktakis, Polychronis D; Giannakopoulos, Evangelos; Vlastos, Dimitris; Matthopoulos, Demetrios P

    2017-02-01

    The interaction of pesticides with environmental factors, such as pH, may result in alterations of their physicochemical properties and should be taken into consideration in regard to their classification. This study investigates the genotoxicity of methidathion and its alkaline hydrolysis by-products in cultured human lymphocytes, using the square-wave voltammetry (square wave-adsorptive cathodic stripping voltammetry (SW-AdCSV) technique) and the cytokinesis block micronucleus assay (CBMN assay). According to the SW-AdCSV data the alkaline hydrolysis of methidathion results in two new molecules, one non-electro-active and a second electro-active which is more genotoxic than methidathion itself in cultured human lymphocytes, inducing higher micronuclei frequencies. The present study confirms the SW-AdCSV technique as a voltammetric method which can successfully simulates the electrodynamics of the cellular membrane.

  6. Active biomonitoring of mussels Mytilus galloprovincialis with integrated use of micronucleus assay and physiological indices to assess harbor pollution.

    PubMed

    Gherras Touahri, Hamida; Boutiba, Zitouni; Benguedda, Wacila; Shaposhnikov, Sergey

    2016-09-15

    The mussels Mytilus galloprovincialis collected from a noncontaminated site (Chaib Rasso) were transplanted during one, three and six months at Ghazaouet harbor (GH), areas with a strong gradient of pollution. The micronucleus test (MN) was selected to monitor the impact of contamination, along with physiological indexes (condition index CI and organo-somatic indexes RI and GSI). The results show a negative correlation of MN variation in gill cells with CI but a positive correlation with transplantation duration. However, a significant correlation was found between the indexes. Moreover, the findings indicate that MN in the hemolymph and gills of transplanted mussels for one, three and six months at GH are significantly higher than those of the reference site. However, no significant differences were noted between the three transplants at the two organs. Monitoring the physiological status of mussels, in parallel with the biomarker measurements, is useful in assessing the impact of contaminants.

  7. Reduction of genotoxicity of a creosote-contaminated soil after fungal treatment determined by the tradescantia-micronucleus test

    SciTech Connect

    Baud-Grasset, S.; Baud-Grasset, F.; Bifulco, J.M.; Meier, J.R.; Ma, T.H.

    1993-01-01

    The fungal degradation of polyaromatic hydrocarbons (PAH) in a contaminated soil from a hazardous waste site was evaluated in a pilot-scale study. As some PAH are known to be mutagens, the Tradescantia-micronucleus test (TRAD-MCN) was selected to evaluate the genotoxicity of the soil before and after fungal treatment. The genotoxicity test was conducted with Tradescantia clone 4430. Cuttings were exposed for 30 hours to different dilutions of soil extracts from the PAH-contaminated soil before and after fungal treatment. The results indicate that the Trad-MCN test has a potential utility for evaluating the efficiency of bioremediation of genotoxic soil contaminants. (Copyright (c) 1993 Elsevier Science Publishers B.V.)

  8. Effects of prostaglandin E2 on the micronucleus formation in mouse bone marrow cells by various mutagens.

    PubMed

    Suzuki, Y; Shimizu, H; Ishikawa, T; Sakaba, H; Fukumoto, M; Okonogi, H; Kadokura, M

    1994-12-01

    The effects of prostaglandin E2 (PGE2), as a trigger of erythroid progenitor cells into the cell cycle, were studied on the induction of micronuclei by various mutagens; with mitomicin C (MMC) the optimal protocol was established. PGE2 itself did not induce any micronuclei in this experiment. The highest frequency of micronuclei and dose-response relationship between PGE2 doses and micronucleus frequency were observed 30 h after injection of MMC to mice administered PGE2 24 h previously. Sensitization by PGE2 pretreatment was also found for other mutagens, such as vincristine, 5-fluorouracil, benzo[a]pyrene, 1,1-dimethylhydrazine and 2-naphthylamine. These results support the hypothesis that accelerating the erythropoiesis increases the frequency of micronuclei induced by mutagens.

  9. Relationships among micronuclei, nucleoplasmic bridges and nuclear buds within individual cells in the cytokinesis-block micronucleus assay.

    PubMed

    Cheong, Han S J; Seth, Isheeta; Joiner, Michael C; Tucker, James D

    2013-07-01

    Micronuclei have been used extensively in studies as an easily evaluated indicator of DNA damage but little is known about their association with other types of damage such as nucleoplasmic bridges and nuclear buds. Here, radiation-induced clastogenic events were evaluated via the cytokinesis-block micronucleus assay in two normal human lymphoblastoid cell lines exposed to neutrons or γ-radiation. DNA damage induced by the chemical agents mitomycin C and phleomycin was also evaluated in two normal and two mitochondrial mutant human lymphoblastoid cell lines. In addition to micronuclei, nucleoplasmic bridges and nuclear buds were enumerated by recording the coincident presence of these end points within individual cells, and the associations among these three end points were evaluated for all treatment conditions. The common odds ratios for micronuclei and nucleoplasmic bridges were found to be significantly larger than unity, indicating that the presence of one or more micronuclei in a cell imposes a significant risk of having one or more nucleoplasmic bridges in that same cell, and vice versa. The strength of this association did not change significantly with radiation dose or concentration of the chemical clastogens. Common odds ratios for association between micronuclei and buds, and between bridges and buds were also found to be significantly higher than unity. However, associations between micronuclei and buds could not be calculated for some treatments due to heterogeneity in the odds ratios and hence may depend on chemical clastogen concentration or radiation dose. This study provides evidence of how paired analyses among genetic end points in the cytokinesis-block micronucleus assay can provide information concerning abnormalities of cell division and possibly about structural chromosomal rearrangements induced by clastogens.

  10. In vivo genotoxicity assessment of sertraline by using alkaline comet assay and the cytokinesis-block micronucleus assay.

    PubMed

    Battal, Dilek; Aktas, Ayca; Sungur, Mehmet Ali; Kadioglu, Ela; Eker, Ebru Derici; Sahin, Nefise Ozlen; Saygi, Sahan

    2013-11-01

    Sertraline, a leading antidepressant in the selective serotonin reuptake inhibitor (SSRI) group of medicine, is the most frequently prescribed drug. In this study, the alkaline comet assay and the cytokinesis-block micronucleus (CBMN) assay were used to investigate genotoxicity potential of sertraline in the peripheral blood lymphocytes (PBLs) of acute and chronic sertraline-treated Wistar albino rats. Male Wistar albino rats (n = 48) were administered low, medium and high doses of sertraline (10, 40, 80 mg/kg) for acute and chronic treatment by employing the gavage method to investigate genotoxicity of the administered drug. The data (tail length, tail intensity and tail moment) were analysed and indicated that there was no statistically significant difference between sertraline-treated groups and the negative control group with respect to DNA damage (p > 0.05). However, it was observed that acute sertraline administration had caused much more DNA damage in comparison with chronic treatment (p < 0.05). According to the data obtained from the CBMN test, an increase in the micronucleus (MN) frequency was detected at chronic and high-dose acute sertraline treatment. Based on the outcome of comet assay, detection of statistically insignificant DNA damage may be due to the fact that sertraline did not cause damage on DNA. Also, increase in frequency of MN in chronic sertraline treatment suggests that chronic sertraline administration might influence some mechanisms of cell division. Therefore, dose adjustment in depressed patients seems significant as it may help prevent further prognosis of the diseases.

  11. In vitro comet and micronucleus assays do not predict morphological transforming effects of silica particles in Syrian Hamster Embryo cells.

    PubMed

    Darne, Christian; Coulais, Catherine; Terzetti, Francine; Fontana, Caroline; Binet, Stéphane; Gaté, Laurent; Guichard, Yves

    2016-01-15

    Crystalline silica particles and asbestos have both been classified as carcinogenic by the International Agency for Research on Cancer (IARC). However, because of the limited data available, amorphous silica was not classifiable. In vitro, the carcinogenic potential of natural crystalline and amorphous silica particles has been revealed by the Syrian Hamster Embryo (SHE) cell transformation assay. On the other hand, the genotoxic potential of those substances has not been investigated in SHE cells. And yet, genotoxicity assays are commonly used for hazard evaluation and they are often used as in vitro assays of reference to predict a possible carcinogenic potential. The main objective of this study was to compare the genotoxic potential and the carcinogenic potential of different crystalline and amorphous silica particles in SHE cells. Three silica samples of different crystallinity were used: natural amorphous silica, partially crystallized silica and quartz silica particles. Their genotoxicity were tested through the in vitro micronucleus assay and the comet assay in SHE, and their carcinogenic potential through the SHE transformation assay. In addition, silica samples were also tested with the same genotoxicity assays in V79 hamster-lung cells, a common in vitro model for particle exposure. Results obtained in the micronucleus and the comet assays show that none of the silica was capable of inducing genotoxic effects in SHE cells and only the amorphous silica induced genotoxic effects in V79 cells. However in the SHE cell transformation assays, the partially crystallized and quartz silica were able to induce morphological cell transformation. Together, these data suggest that, in vitro, the short-term genotoxic assays alone are not sufficient to predict the hazard and the carcinogenic potential of this type of particles; SHE transformation assay appears a more reliable tool for this purpose and should be included in the "in vitro battery assays" for hazard

  12. Genotoxic, Cytotoxic, Antigenotoxic, and Anticytotoxic Effects of Sulfonamide Chalcone Using the Ames Test and the Mouse Bone Marrow Micronucleus Test

    PubMed Central

    Borges, Flávio Fernandes Veloso; Bernardes, Aline; Perez, Caridad Noda; Silva, Daniela de Melo e

    2015-01-01

    Chalcones present several biological activities and sulfonamide chalcone derivatives have shown important biological applications, including antitumor activity. In this study, genotoxic, cytotoxic, antigenotoxic, and anticytotoxic activities of the sulfonamide chalcone N-{4-[3-(4-nitrophenyl)prop-2-enoyl]phenyl} benzenesulfonamide (CPN) were assessed using the Salmonella typhimurium reverse mutation test (Ames test) and the mouse bone marrow micronucleus test. The results showed that CPN caused a small increase in the number of histidine revertant colonies in S. typhimurium strains TA98 and TA100, but not statistically significant (p > 0.05). The antimutagenicity test showed that CPN significantly decreased the number of His+ revertants in strain TA98 at all doses tested (p < 0.05), whereas in strain TA100 this occurred only at doses higher than 50 μg/plate (p < 0.05). The results of the micronucleus test indicated that CPN significantly increased the frequency of micronucleated polychromatic erythrocytes (MNPCE) at 24 h and 48 h, revealing a genotoxic effect of this compound. Also, a significant decrease in polychromatic/normochromatic erythrocyte ratio (PCE/NCE) was observed at the higher doses of CPN at 24 h and 48 h (p < 0.05), indicating its cytotoxic action. CPN co-administered with mitomycin C (MMC) significantly decreased the frequency of MNPCE at almost all doses tested at 24 h (p < 0.05), showing its antigenotoxic activity, and also presented a small decrease in MNPCE at 48 h (p > 0.05). Additionally, CPN co-administered with MMC significantly increased PCE/NCE ratio at all doses tested, demonstrating its anticytotoxic effect. In summary, CPN presented genotoxic, cytotoxic, antigenotoxic, and anticytotoxic properties. PMID:26335560

  13. Assessing the genotoxic potentials of roxarsone in V79 cells using the alkaline Comet assay and micronucleus test.

    PubMed

    Zhang, Yumei; Ying, Jun; Chen, Jun; Hu, Chenyun

    2012-01-24

    Until recently, knowledge about the genotoxicity of roxarsone in vitro or in vivo was limited. This study assessed the genotoxicity of roxarsone in an in vitro system. Roxarsone was tested for potential genotoxicity on V79 cells by a Comet assay and a micronucleus (MN) test, exposing the cells to roxarsone (1-500 μM) and to sodium arsenite (NaAsO₂, 20 μM) solutions for 3-48 h. Roxarsone was found to be cytotoxic when assessed with a commercial cell counting kit (CCK-8) used to evaluate cell viability, and moderately genotoxic in the Comet assay and micronucleus test used to assess DNA damage. The Comet metrics (percentages TDNA, TL, TM) increased significantly in a time- and concentration-dependent manner in roxarsone-treated samples compared with PBS controls (P<0.05), while the data from samples treated with 20 μM NaAsO₂ were comparable to those from 500 μM roxarsone-treated samples. The MN frequency of V79 cells treated with roxarsone was higher than that in the negative control but lower than the frequency in cells treated with 20 μM NaAsO₂. A dose- and time-dependent response in MN induction was observed at 10, 50, 100 and 500 μM doses of roxarsone after 12-48 h exposure time. The DNA damage in V79 cells treated with 500 μM roxarsone was similar to cells exposed to 20 μM NaAsO₂. The uptake of cells was correlated with the DNA damage caused by roxarsone. This investigation depicts the genotoxic potentials of roxarsone to V79 cells, which could lead to further advanced studies on the genotoxicity of roxarsone.

  14. Workers exposed to wood dust have an increased micronucleus frequency in nasal and buccal cells: results from a pilot study.

    PubMed

    Bruschweiler, Evin Danisman; Hopf, Nancy B; Wild, Pascal; Huynh, Cong Khanh; Fenech, Michael; Thomas, Philip; Hor, Maryam; Charriere, Nicole; Savova-Bianchi, Dessislava; Danuser, Brigitta

    2014-05-01

    Wood dust is recognised as a human carcinogen, based on the strong association of wood dust exposure and the elevated risk of malignant tumours of the nasal cavity and paranasal sinuses [sino-nasal cancer (SNC)]. The study aimed to assess genetic damage in workers exposed to wood dust using biomarkers in both buccal and nasal cells that reflect genome instability events, cellular proliferation and cell death frequencies. Nasal and buccal epithelial cells were collected from 31 parquet layers, installers, carpenters and furniture workers (exposed group) and 19 non-exposed workers located in Switzerland. Micronucleus (MN) frequencies were scored in nasal and buccal cells collected among woodworkers. Other nuclear anomalies in buccal cells were measured through the use of the buccal micronucleus cytome assay. MN frequencies in nasal and buccal cells were significantly higher in the exposed group compared to the non-exposed group; odds ratio for nasal cells 3.1 [95% confidence interval (CI) 1.8-5.1] and buccal cells 1.8 (95% CI 1.3-2.4). The exposed group had higher frequencies of cells with nuclear buds, karyorrhectic, pyknotic, karyolytic cells and a decrease in the frequency of basal, binucleated and condensed cells compared to the non-exposed group. Our study confirms that woodworkers have an elevated risk for chromosomal instability in cells of the aerodigestive tract. The MN assay in nasal cells may become a relevant biomonitoring tool in the future for early detection of SNC risk. Future studies should seek to standardise the protocol for MN frequency in nasal cells similar to that for MN in buccal cells.

  15. Genotoxic, Cytotoxic, Antigenotoxic, and Anticytotoxic Effects of Sulfonamide Chalcone Using the Ames Test and the Mouse Bone Marrow Micronucleus Test.

    PubMed

    Silva, Carolina Ribeiro E; Borges, Flávio Fernandes Veloso; Bernardes, Aline; Perez, Caridad Noda; Silva, Daniela de Melo E; Chen-Chen, Lee

    2015-01-01

    Chalcones present several biological activities and sulfonamide chalcone derivatives have shown important biological applications, including antitumor activity. In this study, genotoxic, cytotoxic, antigenotoxic, and anticytotoxic activities of the sulfonamide chalcone N-{4-[3-(4-nitrophenyl)prop-2-enoyl]phenyl} benzenesulfonamide (CPN) were assessed using the Salmonella typhimurium reverse mutation test (Ames test) and the mouse bone marrow micronucleus test. The results showed that CPN caused a small increase in the number of histidine revertant colonies in S. typhimurium strains TA98 and TA100, but not statistically significant (p > 0.05). The antimutagenicity test showed that CPN significantly decreased the number of His+ revertants in strain TA98 at all doses tested (p < 0.05), whereas in strain TA100 this occurred only at doses higher than 50 μg/plate (p < 0.05). The results of the micronucleus test indicated that CPN significantly increased the frequency of micronucleated polychromatic erythrocytes (MNPCE) at 24 h and 48 h, revealing a genotoxic effect of this compound. Also, a significant decrease in polychromatic/normochromatic erythrocyte ratio (PCE/NCE) was observed at the higher doses of CPN at 24 h and 48 h (p < 0.05), indicating its cytotoxic action. CPN co-administered with mitomycin C (MMC) significantly decreased the frequency of MNPCE at almost all doses tested at 24 h (p < 0.05), showing its antigenotoxic activity, and also presented a small decrease in MNPCE at 48 h (p > 0.05). Additionally, CPN co-administered with MMC significantly increased PCE/NCE ratio at all doses tested, demonstrating its anticytotoxic effect. In summary, CPN presented genotoxic, cytotoxic, antigenotoxic, and anticytotoxic properties.

  16. Solanum paniculatum L. leaf and fruit extracts: assessment of modulation of cytotoxicity and genotoxicity by micronucleus test in mice.

    PubMed

    Vieira, Pabline Marinho; Paula, José Realino; Chen-Chen, Lee

    2010-12-01

    Solanum paniculatum L. is a plant species widespread throughout tropical America, especially in the Brazilian Savanna region. It is used in Brazil for culinary purposes and in folk medicine to treat liver and gastric dysfunctions, as well as hangovers. Previous studies with S. paniculatum ethanolic leaf extract (ELE) or ethanolic fruit extract (EFE) demonstrated that they have no genotoxic activity meant either in the micronucleus test in mice or in the phage induction SOS Inductest in bacterial strains; however, cytotoxicity was demonstrated in both tests. Because of the spread use of this plant as a therapeutic resource and food, the present study aimed at evaluating the modulator effects of S. paniculatum ELE or EFE against mitomycin C (MMC) using the mouse bone marrow micronucleus test. This short-term test was used to detect the acute effects of responsive erythropoiesis after 24- and 48-hour exposure periods. Swiss-Webster mice were orally treated with three different concentrations (100, 200, or 300 mg/kg) of ELE or EFE simultaneously with a single dose of MMC (4 mg/kg i.p.). Antigenotoxicity was evaluated using the frequency of micronucleated polychromatic erythrocytes (MNPCEs), whereas anticytotoxicity was assessed by the polychromatic/normochromatic erythrocyte ratio. Our results demonstrated that neither the ELE nor EFE of S. paniculatum protected cells against the cytotoxic action of MMC. Nevertheless, the present study showed the antimutagenic effect of ELE after a 24-hour treatment (reduction in the frequencies of MNPCEs after a 48-hour treatment with ELE can be due to toxicity) and no antimutagenic action of the EFE treatment against the aneugenic and/or clastogenic activities of MMC.

  17. Cytogenetic damage after 131-iodine treatment for hyperthyroidism and thyroid cancer. A study using the micronucleus test.

    PubMed

    Gutiérrez, S; Carbonell, E; Galofré, P; Creus, A; Marcos, R

    1999-12-01

    To detect the incidence and persistence of potential chromosome damage induced by iodine-131 therapy, we applied the cytokinesis-block micronucleus assay to peripheral blood lymphocytes from hyperthyroidism and thyroid cancer patients treated with 131I. Two groups of patients were evaluated in a longitudinal study; one group was composed of 47 hyperthyroid patients and the other of 39 thyroid cancer patients. In the hyperthyroidism group, the micronuclei frequency was determined before 131I therapy and 1 week, 1 month and 3 months after it. Furthermore, an additional sample was taken from a subgroup of 17 hyperthyroidism patients 6 months after treatment. In the thyroid cancer group, the analysis was also conducted over time, and four samples were studied: before treatment and 1 week, 6 months and 1 year later. Simultaneously, a cross-sectional study was performed with 70 control subjects and 54 thyroid cancer patients who had received the last therapeutic dose 1-6 years before the present study. In the hyperthyroidism group a significant increase in the micronuclei average was found over time. In the sample obtained 6 months after therapy, the micronuclei mean frequency was practically the same as in the sample taken 3 months before. In the thyroid cancer group a twofold increase in the frequency of micronuclei was seen 1 week after therapy. Although this value decreased across time, the micronuclei frequency obtained 1 year after 131I therapy remained higher than the value found before it. Concerning the data from the cross-sectional study, a significant increase in the frequency of micronuclei was detected in the subgroup of thyroid cancer patients treated between 1 and 3 years before the current study. These results indicate that exposure to 131I therapy induces chromosome damage in peripheral lymphocytes and that the cytokinesis-block micronucleus assay is sensitive enough to detect the genetic damage by exposure to sufficiently high levels of radiation from

  18. Arsenite as the probable active species in the human carcinogenicity of arsenic: mouse micronucleus assays on Na and K arsenite, orpiment, and Fowler's solution.

    PubMed Central

    Tinwell, H; Stephens, S C; Ashby, J

    1991-01-01

    Sodium arsenite, potassium arsenite, and Fowler's solution (arsenic trioxide dissolved in potassium bicarbonate) are equally active in the mouse bone marrow micronucleus assay (approximately 10 mg/kg by IP injection). The natural ore orpiment (principally As2S3) was inactive despite blood levels of arsenic of 300 to 900 ng/mL in treated mice at 24 hr. Sodium arsenite was active in three strains of mice. It is suggested that the human lung cancer observed among arsenic ore smelters and the skin cancer among people exposed therapeutically to Fowler's solution, have, as their common origin, the genotoxic arsenite ion AsO2-. The difficulty experienced when attempting to demonstrate rodent carcinogenicity for derivatives of arsenic suggests that the bone marrow micronucleus assay may act as a useful assay for potentially carcinogenic arsenic derivatives. PMID:1821373

  19. In vitro micronucleus assay for the analysis of total particulate matter in cigarette smoke: comparison of flow cytometry and laser scanning cytometry with microscopy.

    PubMed

    Yao, Jianhua; Gao, Qian; Mi, Qili; Li, Xuemei; Miao, Mingming; Cheng, Peng; Luo, Ying

    2013-08-15

    The possible genotoxicity of the total particulate matter (TPM) in cigarette smoke has typically been evaluated using the in vitro micronucleus assay. In recent years, automated scoring techniques have been developed to replace the manual counting process in this assay. However, these automated scoring techniques have not been applied in routine genotoxicity assays for the analysis of TPM to improve the assay efficiency. Chinese hamster ovary (CHO) cells were treated with TPM produced from 14 types of cigarettes at five concentrations (25-200μg/ml) without exogenous metabolic activation. The three following methods were used to score the micronucleus (MN) frequency: (a) flow cytometry with SYTOX and EMA dyes, which differentially stain micronuclei and apoptotic/necrotic chromatin to enhance assay reliability; (b) laser scanning cytometry with FITC and PI dyes, which is a system that combines the analytical capabilities of flow and image cytometry; and (c) visual microcopy with Giemsa dye. The test results obtained using the three methods were compared using correlation analysis. The key findings for this set of compounds include the following: (a) both flow cytometry- and laser scanning cytometry-based methods were effective for MN identification, (b) the three scoring methods could detect dose-dependent micronucleus formation for the 14 types of TPM, and (c) the MN frequencies that were measured in the same samples by flow cytometry, laser scanning cytometry, and visual microscopy were highly correlated, and there were no significant differences (p>0.05). In conclusion, both flow cytometry and laser scanning cytometry can be used to evaluate the MN frequency induced by TPM without exogenous metabolic activation. The simpler and faster processing and the high correlation of the results make these two automatic methods appropriate tools for use in in vitro micronucleus assays for the analysis of TPM using CHO cells.

  20. HUMN project initiative and review of validation, quality control and prospects for further development of automated micronucleus assays using image cytometry systems.

    PubMed

    Fenech, Michael; Kirsch-Volders, Micheline; Rossnerova, Andrea; Sram, Radim; Romm, Horst; Bolognesi, Claudia; Ramakumar, Adarsh; Soussaline, Francoise; Schunck, Christian; Elhajouji, Azeddine; Anwar, Wagida; Bonassi, Stefano

    2013-08-01

    The use of micronucleus (MN) assays in in vitro genetic toxicology testing, radiation biodosimetry and population biomonitoring to study the genotoxic impacts of environment gene-interactions has steadily increased over the past two decades. As a consequence there has been a strong interest in developing automated systems to score micronuclei, a biomarker of chromosome breakage or loss, in mammalian and human cells. This paper summarises the outcomes of a workshop on this topic, organised by the HUMN project, at the 6th International Conference on Environmental Mutagenesis in Human Populations at Doha, Qatar, 2012. The aim of this paper is to summarise the outcomes of the workshop with respect to the set objectives which were: (i) Review current developments in automation of micronucleus assays by image cytometry; (ii) define the performance characteristics of automated MN scoring using image cytometry and methods of assessment for instrument validation and quality control and (iii) discuss the design of inter-laboratory comparisons and standardisation of micronucleus assays using automated image cytometry systems. It is evident that automated scoring of micronuclei by automated image cytometry using different commercially available platforms [e.g. Metafer (MetaSystems), Pathfinder™ (IMSTAR), iCyte(®) (Compucyte)], particularly for lymphocytes, is at a mature stage of development with good agreement between visual and automated scoring across systems (correlation factors ranging from 0.58 to 0.99). However, a standardised system of validation and calibration is required to enable more reliable comparison of data across laboratories and across platforms. This review identifies recent progress, important limitations and steps that need to be taken into account to enable the successful universal implementation of automated micronucleus assays by image cytometry.

  1. Genotoxicity assessment of particulate matter emitted from heavy-duty diesel-powered vehicles using the in vivo Vicia faba L. micronucleus test.

    PubMed

    Corrêa, Albertina X R; Cotelle, Sylvie; Millet, Maurice; Somensi, Cleder A; Wagner, Theodoro M; Radetski, Claudemir M

    2016-05-01

    Diesel exhaust particulate matter (PM) can have an impact on the environment due to its chemical constitution. A large number of substances such as organic compounds, sulfates, nitrogen derivatives and metals are adsorbed to the particles and desorption of these contaminants could promote genotoxic effects. The objective of this study was to assess the in vivo genotoxicity profile of diesel exhaust PM from heavy-duty engines. Extracts were obtained through leaching with pure water and chemical extraction using three organic solvents (dichloromethane, hexane, and acetone). The in vivo Vicia faba micronucleus test (ISO 29200 protocol) was used to assess the environmental impact of the samples collected from diesel exhaust PM. The solid diesel PM (soot) dissolved in water, and the different extracts, showed positive results for micronucleus formation. After the addition of EDTA, the aqueous extracts did not show a genotoxic effect. The absence of metals in the organic solvent extract indicated that organic compounds also had a genotoxic effect, which was not observed for a similar sample cleaned in a C18 column. Thus, considering the ecological importance of higher plants in relation to ecosystems (in contrast to Salmonella spp., which are commonly used in mutagenicity studies), the Vicia micronucleus test was demonstrated to be appropriate for complementing prokaryotic or in vitro tests on diesel exhaust particulate matter included in risk assessments.

  2. Vinblastine and diethylstilboestrol tested in the in vitro mammalian cell micronucleus test (MNvit) at Swansea University UK in support of OECD draft Test Guideline 487.

    PubMed

    Johnson, George E; Jenkins, Gareth J; Thomas, Adam D; Doak, Shareen H

    2010-10-29

    The known aneugens vinblastine and diethylstilboestrol (DES) were tested in the in vitro micronucleus assay, with and without cytokinesis block in Chinese hamster CHO cells, at the laboratories of Swansea University, Swansea, UK. These experiments were carried out to determine the suitability of the cell death and cytostasis measures used in the assay, as recommended in the draft OECD Test Guideline 487, 2007. Both compounds were positive in the assay without cytokinesis block at concentrations giving approximately 50% or less cell death and cytostasis, using relative population doublings and relative increase in cell counts. Moreover, both compounds were positive in the assay with cytokinesis block at concentrations giving approximately 50% cell death and cytostasis, using replicative index. Vinblastine was also positive for mitotic slippage, causing micronuclei in mononucleate cells with cytokinesis block. Relative population doublings and relative increase in cell counts were appropriate measures of cell death and cytostasis for the non-cytokinesis block in vitro micronucleus assay. In the cytokinesis blocked micronucleus assay, replicative index and cytokinesis block proliferation index were suitable cell death and cytostasis measures.

  3. Study of the genotoxic and cytotoxic effects of the α-, β-, and γ- Hexachlorocyclohexane isomers in human lymphocyte cells using the cytokinesis-block micronucleus assay.

    PubMed

    Ennaceur, Soukaina

    2017-01-01

    The genotoxic potential of hexachlorocyclohexane (HCH) isomers (α-, β-, and γ-) which are organochlorine pesticides was tested in peripheral blood lymphocyte cultures from two donors by using the cytokinesis-block micronucleus assay. Micronucleus (MN) frequency, binucleated cells with micronucleus (BNMN), and cytokinesis-blocked proliferation index (CBPI) were determined as genotoxic and cytotoxic endpoints. At the concentration ranges tested (12.5-100 μg.L (-1)), all HCH isomers induced dose-dependent cytotoxic effects, γ-HCH being the most toxic. This isomer was also able to induce significant increase in MN frequency and BNMN cells indicating a genotoxic potential at 50 and 100 μg.L (-1). The genotoxic test of β-HCH showed a positive induction of MN and BNMN cells at the highest concentration of 100 μg.L (-1) and a significant cytotoxicity at 50 μg.L (-1). Under the experimental condition used, α-HCH was unable to induce any significant increase in MN frequency confirming that α-HCH is a non-genotoxic agent.

  4. Increased micronucleus frequency in peripheral blood lymphocytes contributes to cancer risk in the methyl isocyanate-affected population of Bhopal.

    PubMed

    Senthilkumar, Chinnu Sugavanam; Akhter, Sameena; Malla, Tahir Mohiuddin; Sah, Nand Kishore; Ganesh, Narayanan

    2015-01-01

    The Bhopal gas tragedy involving methyl isocyanate (MIC) is one of the most horrific industrial accidents in recent decades. We investigated the genotoxic effects of MIC in long-term survivors and their offspring born after the 1984 occurrence. There are a few cytogenetic reports showing genetic damage in the MIC-exposed survivors, but there is no information about the associated cancer risk. The same is true about offspring. For the first time, we here assessed the micronucleus (MN) frequency using cytokinesis-blocked micronucleus (CBMN) assay to predict cancer risk in the MIC-affected population of Bhopal. A total of 92 healthy volunteers (46 MIC- affected and 46 controls) from Bhopal and various regions of India were studied taking gender and age into consideration. Binucleated lymphocytes with micronuclei (BNMN), total number of micronuclei in lymphocytes (MNL), and nuclear division index (NDI) frequencies and their relationship to age, gender and several lifestyle variabilities (smoking, alcohol consumption and tobacco-chewing) were investigated. Our observations showed relatively higher BNMN and MNL (P<0.05) in the MIC-affected than in the controls. Exposed females (EF) exhibited significantly higher BNMN and MNL (P<0.01) than their unexposed counterparts. Similarly, female offspring of the exposed (FOE) also suffered higher BNMN and MNL (P<0.05) than in controls. A significant reduction in NDI (P<0.05) was found only in EF. The affected group of non-smokers and non-alcoholics featured a higher frequency of BNMN and MNL than the control group of non-smokers and non-alcoholics (P<0.01). Similarly, the affected group of tobacco chewers showed significantly higher BNMN and MNL (P<0.001) than the non-chewers. Amongst the affected, smoking and alcohol consumption were not associated with statistically significant differences in BNMN, MNL and NDI. Nevertheless, tobacco-chewing had a preponderant effect with respect to MNL. A reasonable correlation between MNL and

  5. In vivo flow cytometric Pig-a and micronucleus assays: highly sensitive discrimination of the carcinogen/noncarcinogen pair benzo(a)pyrene and pyrene using acute and repeated-dose designs.

    PubMed

    Torous, Dorothea K; Phonethepswath, Souk; Avlasevich, Svetlana L; Mereness, Jared; Bryce, Steven M; Bemis, Jeffrey C; Weller, Pamela; Bell, Sara; Gleason, Carol; Custer, Laura L; MacGregor, James T; Dertinger, Stephen D

    2012-07-01

    Combining multiple genetic toxicology endpoints into a single in vivo study, and/or integrating one or more genotoxicity assays into general toxicology studies, is attractive because it reduces animal use and enables comprehensive comparative analysis using toxicity, metabolism, and pharmacokinetic information from the same animal. This laboratory has developed flow cytometric scoring techniques for monitoring two blood-based genotoxicity endpoints-micronucleated reticulocyte frequency and gene mutation at the Pig-a locus-thereby making combination and integration studies practical. The ability to effectively monitor these endpoints in short-term and repeated dosing schedules was investigated with the carcinogen/noncarcinogen pair benzo(a)pyrene (BP) and pyrene (Pyr). Male Sprague-Dawley rats were treated via oral gavage for 3 or 28 consecutive days with several dose levels of Pyr, including maximum tolerated doses. BP exposure was administered by the same route but at one dose level, 250 or 125 mg/kg/day for 3-day and 28-day studies, respectively. Serial blood samples were collected up to Day 45, and were analyzed for Pig-a mutation with a dual labeling method (SYTO 13 in combination with anti-CD59-PE) that facilitated mutant cell frequency measurements in both total erythrocytes and the reticulocyte subpopulation. A mutant cell enrichment step based on immunomagnetic column separation was used to increase the statistical power of the assay. BP induced robust mutant reticulocyte responses by Day 15, and elevated frequencies persisted until study termination. Mutant erythrocyte responses lagged mutant reticulocyte responses, with peak incidences observed on Day 30 of the 3-day study (43-fold increase) and on Day 42 of the 28-day study (171-fold increase). No mutagenic effects were apparent for Pyr. Blood samples collected on Day 4, and Day 29 for the 28-day study, were evaluated for micronucleated reticulocyte frequency. Significant increases in micronucleus

  6. Measurement of genotoxicity in wastewater samples with the in vitro micronucleus test: results of a round-robin study in the context of standardisation according to ISO.

    PubMed

    Reifferscheid, Georg; Ziemann, Christina; Fieblinger, Dagmar; Dill, Florian; Gminski, Richard; Grummt, Hans-Jürgen; Hafner, Christoph; Hollert, Henner; Kunz, Susanne; Rodrigo, Gregory; Stopper, Helga; Selke, Dorothea

    2008-01-08

    In the course of standardisation of the in vitro micronucleus test for analysis of effluents according to ISO, a national round-robin study was organised by the German Federal Institute of Hydrology (BfG), involving 10 laboratories of private companies, universities and public authorities. The micronucleus assay was performed with the permanently growing Chinese hamster lung fibroblast cell line V79. All participants tested four encoded samples from one municipal and one industrial wastewater treatment plant with and without metabolic activation by S9-mix. Two of these samples were spiked in advance with defined concentrations of the clastogenic substances cyclophosphamide and mitomycin C, respectively. Cyclophosphamide and ethyl methanesulfonate were used as positive controls. The defined assessment criterion for genotoxicity was the lowest dilution of a sample that does not show any significant induction of micronuclei. Cytotoxicity was judged by determining the cell-survival index, i.e. the percentage growth rate of the cells compared with the corresponding negative controls. As supplementary qualitative criteria, the mitotic index and the proliferation index were assessed. All participants successfully established the method within a few weeks and generated viable test results in time. The two non-genotoxic samples were detected as negative by 90% (with S9-mix) and 95% (without S9-mix) of the participants. The mitomycin C-spiked wastewater sample (expected to be positive without S9-mix supplementation) was correctly judged as positive by all laboratories. The cyclophosphamide-spiked sample (expected to be positive with S9-mix addition) was evaluated correctly as genotoxic by 80% of the laboratories. A post-test analysis found evidence that the false negative results were due to technical failure, but not of a methodological nature. In 94% of all tests the sample LID values (lowest ineffective dilution=dilution stage of the sample in the test at which a

  7. Genetic toxicity assessment: employing the best science for human safety evaluation. Part II: Performances of the in vitro micronucleus test compared to the mouse lymphoma assay and the in vitro chromosome aberration assay.

    PubMed

    Lorge, Elisabeth; Lambert, Carine; Gervais, Véronique; Becourt-Lhote, Nathalie; Delongeas, Jean-Luc; Claude, Nancy

    2007-04-01

    The in vitro micronucleus test is commonly used in the early stages of pharmaceutical development as a predictive tool for the regulatory mouse lymphoma assay or in vitro chromosome aberration test. The accumulated data from this assay leads to the suggestion that it could be used as an alternative to the chromosome aberration test or the mouse lymphoma assay in the regulatory genotoxicity battery. In this paper, we present the results of the in vitro micronucleus test on L5178Y mouse lymphoma cells with 25 compounds from Servier research and have compared these results to those obtained in the genotoxicity regulatory battery. All the negative compounds were also negative in the in vitro micronucleus assay. Among the 14 positive compounds, two of them, positive in the mouse lymphoma assay, were found negative in the in vitro micronucleus test. However, this apparent discordance was likely to be due to cytotoxicity- or high concentration-related false positive responses in the mouse lymphoma assay. In addition, we confirmed that the in vitro micronucleus assay is useful for detecting aneugens, especially, when cells in metaphasis and multinucleated cells are also scored and when cells are allowed to recover after the long treatment. On this series of compounds, the in vitro micronucleus assay showed high sensitivity and possibly a better specificity than the mouse lymphoma assay. Thus, the in vitro micronucleus assay was shown to be at least as adequate as the mouse lymphoma assay or the in vitro chromosome aberration test to be used in the standard genotoxicity battery.

  8. In vivo genotoxicity of mercury chloride and lead acetate: Micronucleus test on acridine orange stained fish cells.

    PubMed

    Cavaş, Tolga

    2008-01-01

    The genotoxic effects of mercury chloride and lead acetate were evaluated in vivo using the micronucleus (MN) assay on acridine-orange (AO) stained peripheral blood erythrocytes, gill and fin epithelial cells of Carassius auratus auratus. Fish were exposed to three different concentrations of mercury chloride (MC) (1 microg/, 5 microg/L and 10 microg/L) and lead acetate (LA) (10 microg/L, 50 microg/L and 100 microg/L) for 2, 4 and 6 days. A single dose of 5 mg/L cyclophosphamide was used as a positive control. In addition to micronuclei, nuclear buds (NBs) were assessed in the erythrocytes. The ratio of polychromatic and normochromatic erythrocytes (PCE/NCE) in peripheral blood was also evaluated to assess cytotoxicity. MN frequencies in all three tissues were elevated in fish exposed to both LA and MC. However, NBs showed different sensitivity to metal treatments. MN frequencies in both control and treated fish were highest in gill cells and generally lower in erythrocytes and fin cells. PCE/NCE rations decreased in relation to MC and LA treatments. The results of this study indicate that LA and MC have genotoxic and cytotoxic damage in fish and confirmed that AO staining is a suitable technique for in vivo MN test in fish.

  9. Genotoxicity evaluation of metformin and glimepiride by micronucleus assay in exfoliated urothelial cells of type 2 diabetes mellitus patients.

    PubMed

    Harishankar, M K; Logeshwaran, S; Sujeevan, S; Aruljothi, K N; Dannie, M A; Devi, A

    2015-09-01

    Micronucleus (MN) assay was performed on the exfoliated urothelial cells to detect the genotoxic effects of the anti-hyperglycemic drugs, metformin and glimepiride in T2DM patients and to use it as a biomarker for DNA damage by assessing the frequency of micronuclei in the exfoliated urothelial cells. A total of 201 subjects (147 T2DM patients & 54 Normal cases) were selected from diverse age groups (25-75 years) and the mean MN frequency was examined per 1000 cells in all the subjects. Relative to the control group (5.02 ± 1.01), an increased MN frequency was observed in females (26.15 ± 2.15) when compared to males (23.08 ± 2.09) in T2DM patients. Further analysis showed that there was a profound increase in the number of MN in the patients using metformin alone (23.02 ± 4.44), or combination of metformin & glimepiride (24.98 ± 2.87) than to the subjects using glimepiride alone (17.52 ± 3.28). It has been proven by this simple, reliable and non-invasive method that metformin has a potential role in causing genotoxicity and that the MN observed in exfoliated urothelial cells could be used as a reliable biomarker in monitoring the genotoxic risk of the anti-hyperglycemic drugs.

  10. The Tradescantia micronucleus assay is a highly sensitive tool for the detection of low levels of radioactivity in environmental samples.

    PubMed

    Mišík, Miroslav; Krupitza, Georg; Mišíková, Katarina; Mičieta, Karol; Nersesyan, Armen; Kundi, Michael; Knasmueller, Siegfried

    2016-12-01

    Environmental contamination with radioactive materials of geogenic and anthropogenic origin is a global problem. A variety of mutagenicity test procedures has been developed which enable the detection of DNA damage caused by ionizing radiation which plays a key role in the adverse effects caused by radioisotopes. In the present study, we investigated the usefulness of the Tradescantia micronucleus test (the most widely used plant based genotoxicity bioassay) for the detection of genetic damage caused by environmental samples and a human artifact (ceramic plate) which contained radioactive elements. We compared the results obtained with different exposure protocols and found that direct exposure of the inflorescences is more sensitive and that the number of micronuclei can be further increased under "wet" conditions. The lowest dose rate which caused a significant effect was 1.2 μGy/h (10 h). Comparisons with the results obtained with other systems (i.e. with mitotic cells of higher plants, molluscs, insects, fish and human lymphocytes) show that the Tradescantia MN assay is one to three orders of magnitude more sensitive as other models, which are currently available. Taken together, our findings indicate that this method is due to its high sensitivity a unique tool, which can be used for environmental biomonitoring in radiation polluted areas.

  11. Is a semi-automated approach indicated in the application of the automated micronucleus assay for triage purposes?

    PubMed

    Thierens, H; Vral, A; Vandevoorde, C; Vandersickel, V; de Gelder, V; Romm, H; Oestreicher, U; Rothkamm, K; Barnard, S; Ainsbury, E; Sommer, S; Beinke, C; Wojcik, A

    2014-06-01

    Within the EU MULTIBIODOSE project, the automated micronucleus (MN) assay was optimised for population triage in large-scale radiological emergencies. For MN scoring, two approaches were applied using the Metafer4 platform (MetaSystems, Germany): fully automated scoring and semi-automated scoring with visual inspection of the gallery of MN-positive objects. Dose-response curves were established for acute and protracted whole-body and partial-body exposures. A database of background MN yields was set up, allowing determination of the dose detection threshold in both scoring modes. An analysis of the overdispersion of the MN frequency distribution σ(2)/µ obtained by semi-automated scoring showed that the value of this parameter represents a reliability check of the calculated equivalent total body dose in case the accident overexposure is a partial-body exposure. The elaborated methodology was validated in an accident training exercise. Overall, the semi-automated scoring procedure represents important added value to the automated MN assay.

  12. Cytogenetic biomonitoring of Brazilian workers exposed to pesticides: micronucleus analysis in buccal epithelial cells of soybean growers.

    PubMed

    Bortoli, Giorgia Moura de; Azevedo, Mariana Barbieri de; Silva, Luciano Basso da

    2009-04-30

    Pesticides have been considered potential chemical mutagens and various agrochemical ingredients possess mutagenic properties. Biomonitoring provides a useful tool to estimate the genetic risk from exposure to a complex mixture of chemicals. In general genetic damage associated with pesticides occurs in human populations subject to high exposure levels due to intensive use, misuse or failure of control measures. Few studies have been carried out using the micronucleus (MN) analysis in buccal cells of farm workers and, from the available data, only one has found a positive relationship. Micronuclei were analyzed in 29 Brazilian workers exposed to pesticides in soybean fields and in 37 non-exposed individuals. The results obtained indicate that the mean number of cells with MN in the exposed group (3.55+/-2.13) was significantly higher than in the control group (1.78+/-1.23). The number of cells with MN was not influenced by age, smoking habit, smoking time, number of cigarettes/day, alcohol consumption and years of exposure to pesticides. The genotoxic potential of the pesticides used in soybean fields may explain the detectable increase of cells with MN in exposed workers.

  13. The cytokinesis-blocked micronucleus assay: dose-response calibration curve, background frequency in the population and dose estimation.

    PubMed

    Rastkhah, E; Zakeri, F; Ghoranneviss, M; Rajabpour, M R; Farshidpour, M R; Mianji, F; Bayat, M

    2016-03-01

    An in vitro study of the dose responses of human peripheral blood lymphocytes was conducted with the aim of creating calibrated dose-response curves for biodosimetry measuring up to 4 Gy (0.25-4 Gy) of gamma radiation. The cytokinesis-blocked micronucleus (CBMN) assay was employed to obtain the frequencies of micronuclei (MN) per binucleated cell in blood samples from 16 healthy donors (eight males and eight females) in two age ranges of 20-34 and 35-50 years. The data were used to construct the calibration curves for men and women in two age groups, separately. An increase in micronuclei yield with the dose in a linear-quadratic way was observed in all groups. To verify the applicability of the constructed calibration curve, MN yields were measured in peripheral blood lymphocytes of two real overexposed subjects and three irradiated samples with unknown dose, and the results were compared with dose values obtained from measuring dicentric chromosomes. The comparison of the results obtained by the two techniques indicated a good agreement between dose estimates. The average baseline frequency of MN for the 130 healthy non-exposed donors (77 men and 55 women, 20-60 years old divided into four age groups) ranged from 6 to 21 micronuclei per 1000 binucleated cells. Baseline MN frequencies were higher for women and for the older age group. The results presented in this study point out that the CBMN assay is a reliable, easier and valuable alternative method for biological dosimetry.

  14. Profile of micronucleus frequencies and nuclear abnormalities in different species of electric fishes (Gymnotiformes) from the Eastern Amazon

    PubMed Central

    Melo, Karina Motta; Alves, Ingrid Reale; Pieczarka, Julio Cesar; de Oliveira David, José Augusto; Nagamachi, Cleusa Yoshiko; Grisolia, Cesar Koppe

    2013-01-01

    The frequency of spontaneous micronucleus (MN) formation in fish species needs to be determined to evaluate their usefulness for genotoxic biomonitoring. The definition of a good bioindicator takes into account the current knowledge of its metabolic traits as well as other factors including its feeding behavior and relationship to the environment. In this study, we compared the basal frequencies of micronucleated erythrocytes and nuclear abnormalities (NA) among different species of the fish Order Gymnotiformes (Rhamphichthys marmoratus, Steatogenys elegans, Sternopygus macrurus, Parapteronotus hasemani, Gymnotus mamiraua, Gymnotus arapaima, Brachyhypopomus beebei, Brachyhypopomus n. sp. BENN) sampled in several localities of the Eastern Amazon. A baseline of MN and NA frequency in these fish was determined, enabling the identification of potentially useful species as models for genotoxicity studies. Only one impacted sample collected at a site in the River Caripetuba showed a significant number of NAs, which may be due to the release of wastewater by neighbouring mining industries and by the burnt fuel released by the small boats used by a local community. Our results may provide support for further studies in areas of the Eastern Amazon affected by mining, deforestation and other anthropogenic activities. PMID:24130451

  15. Safety evaluation of a triazine compound nitromezuril by assessing bacterial reverse mutation, sperm abnormalities, micronucleus and chromosomal aberration.

    PubMed

    Fei, Chenzhong; Zhang, Jie; Lin, Yang; Wang, Xiaoyang; Zhang, Keyu; Zhang, Lifang; Zheng, Wenli; Wang, Mi; Li, Tao; Xiao, Sui; Xue, Feiqun; Wang, Chunmei

    2015-04-01

    Nitromezuril (NZL) is a novel triazine compound that exhibits remarkable anticoccidial activity. However, mutagenicity and genotoxicity of NZL have not been evaluated to date. This study evaluated the potential risks of NZL by testing for bacterial reverse mutation (Ames), mouse sperm abnormality (SA), bone marrow micronucleus (MN) and chromosomal aberration (CA). Mice were orally administered with NZL at 385, 192 and 96 mg/kg, corresponding to 0.5 ×, 0.25 × and 0.125 × the LD50 of NZL, respectively. No significant increases in SA and CA were found in mice treated with NZL for 5d and 3d, respectively (P>0.05). NZL at 96-385 mg/kg did not have significant influence on micronucleated polychromatic erythrocyte counts (P>0.05). These results suggest that NZL is not genotoxic. However, Ames test results were positive both with and without the S9 system for Salmonella typhimurium TA98 and TA100, suggesting that NZL may be mutagenic. The mutagenic effects of NZL were different in in vitro and in vivo assays. Further studies should be conducted to confirm the safety of using and developing NZL as a novel anticoccidial drug.

  16. Adapting the buccal micronucleus cytome assay for use in wild birds: age and sex affect background frequency in pigeons.

    PubMed

    Shepherd, G L; Somers, C M

    2012-03-01

    Micronucleus (MN) formation has been used extensively as a biomarker of damage from genotoxic exposures. The Buccal MN Cytome (BMCyt) assay provides a noninvasive means of quantifying MN frequency in humans, but it has not been developed for use in wildlife. We adapted the BMCyt assay for use in wild birds, with a focus on feral pigeons (Columba livia) as a potential indicator species. Five of six urban bird species sampled using oral cavity swabs produced sufficient buccal cells for the BMCyt assay. The body size of species sampled ranged almost 100-fold (~60 to 5,000 g), but was a not major factor influencing the number of buccal cells collected. Pigeon cells were stained and scored following published BMCyt assay protocols for humans, but with a modified fixation approach using heat and methanol. Pigeons had the same common nuclear abnormalities reported in human studies, and a similar background MN formation frequency of 0.88 MN/1,000 cells. Adult pigeons had on average a threefold higher rate of MN formation than juveniles, and males had a 1.4- to 2.2-fold higher frequency than females. Domestic and feral pigeons did not differ in overall MN frequency. Our results indicate that the BMCyt assay can be used on wild birds, and could provide a means of assessing environmental genotoxicity in pigeons, a useful indicator species. However, bird age and sex are important factors affecting background MN frequency, and thereby the design of environmental studies.

  17. Micronucleus frequency and hematologic index in Colossoma macropomum (Pisces, Ariidae) for environmental impact assessment at a protected area in Brazil

    SciTech Connect

    Sousa, Debora Batista Pinheiro; Neta, Raimunda Nonata Fortes Carvalho

    2014-10-06

    This study used micronucleus assays and erythrocyte indices in the freshwater fish tambaqui, Colossoma macropomum, to assess environmental impacts in the Environmental Protection Area at Maracanã, São Luis, Brazil. Fish were sampled from two locations within the protected area, Serena Lagoon and Ambude River, on four occasions. Biometric data (length and weight) and an aliquot of blood were collected from each fish for analysis. Erythrocyte indices including: mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were calculated, and blood samples were examined for micronuclei and nuclear morphological changes. Micronuclei were found in fish from both locations, although the frequency was higher in fish from Ambude River. Nuclear morphological changes were identified only in fish collected from Ambude River. Several nuclear morphological changes were found in erythrocytes stained with Giemsa, including: micronuclei and binucleate nuclei. On average, erythrocyte indices were lower in fish collected from Ambude River than in those from Serena Lagoon. Our results indicate that micronuclei and erythrocyte indices can be used in C. macropomum as indicators of environmental health.

  18. International prevalidation studies of the EpiDerm 3D human reconstructed skin micronucleus (RSMN) assay: transferability and reproducibility.

    PubMed

    Aardema, Marilyn J; Barnett, Brenda C; Khambatta, Zubin; Reisinger, Kerstin; Ouedraogo-Arras, Gladys; Faquet, Brigitte; Ginestet, Anne-Claire; Mun, Greg C; Dahl, Erica L; Hewitt, Nicola J; Corvi, Raffallea; Curren, Rodger D

    2010-08-30

    Recently, a novel in vitro reconstructed skin micronucleus (RSMN) assay incorporating the EpiDerm 3D human skin model (Curren et al., Mutat. Res. 607 (2006) 192-204; Mun et al., Mutat. Res. 673 (2009) 92-99) has been shown to produce comparable data when utilized in three different laboratories in the United States (Hu et al., Mutat. Res. 673 (2009) 100-108). As part of a project sponsored by the European cosmetics companies trade association (COLIPA), with a contribution from the European Center for the Validation of Alternative Methods (ECVAM), international prevalidation studies of the RSMN assay have been initiated. The assay was transferred and optimized in two laboratories in Europe, where dose-dependent, reproducibly positive results for mitomycin C and vinblastine sulfate were obtained. Further intra- and inter-laboratory reproducibility of the RSMN assay was established by testing three coded chemicals, N-ethyl-N-nitrosourea, cyclohexanone, and mitomycin C. All chemicals were correctly identified by all laboratories as either positive or negative. These results support the international inter-laboratory and inter-experimental reproducibility of the assay and reinforce the conclusion that the RSMN assay in the EpiDerm 3D human skin model is a valuable in vitro method for assessment of genotoxicity of dermally applied chemicals.

  19. Toxicity effect of dichlorvos on loach (Misgurnus anguillicaudatus) assessed by micronucleus test, hepatase activity analysis and comet assay.

    PubMed

    Nan, Ping; Yan, Shuaiguo; Li, Li; Chen, Jianjun; Du, Qiyan; Chang, Zhongjie

    2015-06-01

    Pesticides and other chemicals at environmental concentrations often have detrimental effects. Many aquatic species are particularly threatened because of their susceptibility and also because water environment are often polluted. This study preliminarily evaluated the toxicity effect of dichlorvos (DDVP) on loach (Misgurnus anguillicaudatus) using the methods of micronucleus (MN) test, hepatase activity and comet assay. The tested results showed that indeed very little DDVP had strong toxicity effect on loach and its 50% lethal concentration (LC50) at 24 h, 48 h and 96 h was 8.38 μg l(-1), 7.168 μg l(-1) and 6.411 μg l(-1), respectively; The glutamic-pyruvic transaminase (GPT) and glutamic-oxalacetic transaminase (GOT) activity of loach liver decreased; meanwhile, the GPT and GOT activity of loach serum, the MN rate (‰) and three comet parameters of tested fish increased with the increase in the treatment concentration and treatment time of DDVP, and there was significant difference between control group and each treatment group (p < 0.05). These results suggested that DDVP residues might become toxic chemical contaminant in environment and would threaten aquatic and other organisms.

  20. In vivo micronucleus test in the assessment of cytogenotoxicity of landfill leachates in three animal models from various ecological habitats.

    PubMed

    Alimba, Chibuisi G; Bakare, Adekunle A

    2016-03-01

    The in vivo micronucleus (MN) test, a standard test for the genotoxicity screening of xenobiotics, was used to evaluate the cytotoxic and genotoxic activities of landfill leachates in Clarias gariepinus, Coturnix coturnix japonica and Rattus norvegicus. These organisms were exposed to various sub-lethal concentrations (1-50%) of Olusosun and Aba Eku landfill leachates. At post exposure, peripheral erythrocytes from catfish and quail, and bone marrow cells of quail and rat were subjected to MN analysis following standard protocols. The leachates induced significant increase in MN formation and total nuclear abnormalities (NAs) in the peripheral erythrocytes of catfish and quail. NAs occurred in the order; BN > BL > LB > NT in the catfish and BN > BudN > TLN > TN in quail. There was significant increase in MN formation in the bone marrow cells of quail, and micronucleated polychromatic erythrocytes and micronucleated normochromatic erythrocytes formation in the bone marrow of rats. The concentration dependent significant (p < 0.05) decrease in the PCE/NCE ratio in the bone marrow of the leachate treated rats suggest alterations in the bone marrow cell proliferation, leading to the suppression of immature erythrocytes (PCE). MN induction showed positive corrections with leachate concentrations in the test organisms; and it increased with exposure duration in the catfish. Indiscriminate disposal of solid waste generates leachates containing multiple xenobiotics that are capable of increasing genomic instability among vertebrates inhabiting various ecological habitats.

  1. Correlation of In Vivo Versus In Vitro Benchmark Doses (BMDs) Derived From Micronucleus Test Data: A Proof of Concept Study.

    PubMed

    Soeteman-Hernández, Lya G; Fellows, Mick D; Johnson, George E; Slob, Wout

    2015-12-01

    In this study, we explored the applicability of using in vitro micronucleus (MN) data from human lymphoblastoid TK6 cells to derive in vivo genotoxicity potency information. Nineteen chemicals covering a broad spectrum of genotoxic modes of action were tested in an in vitro MN test using TK6 cells using the same study protocol. Several of these chemicals were considered to need metabolic activation, and these were administered in the presence of S9. The Benchmark dose (BMD) approach was applied using the dose-response modeling program PROAST to estimate the genotoxic potency from the in vitro data. The resulting in vitro BMDs were compared with previously derived BMDs from in vivo MN and carcinogenicity studies. A proportional correlation was observed between the BMDs from the in vitro MN and the BMDs from the in vivo MN assays. Further, a clear correlation was found between the BMDs from in vitro MN and the associated BMDs for malignant tumors. Although these results are based on only 19 compounds, they show that genotoxicity potencies estimated from in vitro tests may result in useful information regarding in vivo genotoxic potency, as well as expected cancer potency. Extension of the number of compounds and further investigation of metabolic activation (S9) and of other toxicokinetic factors would be needed to validate our initial conclusions. However, this initial work suggests that this approach could be used for in vitro to in vivo extrapolations which would support the reduction of animals used in research (3Rs: replacement, reduction, and refinement).

  2. Determination of mutagenicity and genotoxicity of indium tin oxide nanoparticles using the Ames test and micronucleus assay.

    PubMed

    Akyıl, Dilek; Eren, Yasin; Konuk, Muhsin; Tepekozcan, Aykut; Sağlam, Esra

    2016-09-01

    In this study, the mutagenicity and genotoxicity of indium tin oxide (ITO) nanomaterial were assessed using two standard genotoxicity assays, the Salmonella reverse mutation assay (Ames test) and the in vitro micronucleus (MN) assay. Seven different concentrations (12.5, 25, 50, 75, 100, 125, and 150 µg/plate) of this nanomaterial were tested using the Ames test on the TA98 and TA100 strains in the presence and absence of the S9 mixture. At all the concentrations tested, this substance did not significantly increase the number of revertant colonies compared with the control with or without S9 mixture. The genotoxic effects of ITO were investigated in human peripheral lymphocytes treated with 125, 250, 500, and 750 µg/ml concentrations of this substance for 24- and 48-h treatment periods using an MN test. Nuclear division index (NDI) was also calculated in order to determine the cytotoxicity of ITO. It was determined that ITO increased MN frequency in the 750 µg/ml concentration in 24- and 48-h treatments. In addition, ITO dose dependently decreased the NDI significantly for two treatment periods.

  3. Combining the in vivo comet and micronucleus assays: a practical approach to genotoxicity testing and data interpretation.

    PubMed

    Vasquez, Marie Z

    2010-03-01

    Despite regulatory directives requiring the reduction of animal use in safety testing, recent modifications to genotoxicity testing guidelines now propose the use of two in vivo genotoxicity assays as a follow-up to an in vitro positive (International Conference on Harmonization Consensus Draft Guidance S2[R1] released March, 2008). To address both goals, the in vivo comet and micronucleus (MN) assays can be successfully combined into one informative study. Combining these two assays with such differences in sensitivity, endpoints measured and the type of data generated significantly improves upon the current standard capabilities for detecting genotoxicity without requiring additional animals. But to take full advantage of the benefits of incorporating the comet assay in safety testing, these same differences must be recognized and considered. Developed from over 15 years experience using the in vivo comet and MN assays in genotoxicity testing of chemicals and pharmaceuticals, this paper presents guidelines for the appropriate experimental design, dose selection and data interpretation for combined in vivo comet/MN assay studies. To illustrate the approach, data from combined assay studies are presented and discussed.

  4. RABiT-II: Implementation of a High-Throughput Micronucleus Biodosimetry Assay on Commercial Biotech Robotic Systems.

    PubMed

    Repin, Mikhail; Pampou, Sergey; Karan, Charles; Brenner, David J; Garty, Guy

    2017-02-23

    We demonstrate the use of high-throughput biodosimetry platforms based on commercial high-throughput/high-content screening robotic systems. The cytokinesis-block micronucleus (CBMN) assay, using only 20 μl whole blood from a fingerstick, was implemented on a PerkinElmer cell::explorer and General Electric IN Cell Analyzer 2000. On average 500 binucleated cells per sample were detected by our FluorQuantMN software. A calibration curve was generated in the radiation dose range up to 5.0 Gy using the data from 8 donors and 48,083 binucleated cells in total. The study described here demonstrates that high-throughput radiation biodosimetry is practical using current commercial high-throughput/high-content screening robotic systems, which can be readily programmed to perform and analyze robotics-optimized cytogenetic assays. Application to other commercial high-throughput/high-content screening systems beyond the ones used in this study is clearly practical. This approach will allow much wider access to high-throughput biodosimetric screening for large-scale radiological incidents than is currently available.

  5. Micronucleus frequency and hematologic index in Colossoma macropomum (Pisces, Ariidae) for environmental impact assessment at a protected area in Brazil

    NASA Astrophysics Data System (ADS)

    Sousa, Debora Batista Pinheiro; Neta, Raimunda Nonata Fortes Carvalho

    2014-10-01

    This study used micronucleus assays and erythrocyte indices in the freshwater fish tambaqui, Colossoma macropomum, to assess environmental impacts in the Environmental Protection Area at Maracanã, São Luis, Brazil. Fish were sampled from two locations within the protected area, Serena Lagoon and Ambude River, on four occasions. Biometric data (length and weight) and an aliquot of blood were collected from each fish for analysis. Erythrocyte indices including: mean corpuscular volume, mean corpuscular hemoglobin and mean corpuscular hemoglobin concentration were calculated, and blood samples were examined for micronuclei and nuclear morphological changes. Micronuclei were found in fish from both locations, although the frequency was higher in fish from Ambude River. Nuclear morphological changes were identified only in fish collected from Ambude River. Several nuclear morphological changes were found in erythrocytes stained with Giemsa, including: micronuclei and binucleate nuclei. On average, erythrocyte indices were lower in fish collected from Ambude River than in those from Serena Lagoon. Our results indicate that micronuclei and erythrocyte indices can be used in C. macropomum as indicators of environmental health.

  6. Evaluation of genetic damage in open-cast coal mine workers using the buccal micronucleus cytome assay.

    PubMed

    Rohr, Paula; da Silva, Juliana; da Silva, Fernanda R; Sarmento, Merielen; Porto, Carem; Debastiani, Rafaela; Dos Santos, Carla E I; Dias, Johnny F; Kvitko, Kátia

    2013-01-01

    Coal is the largest fossil fuel source used for the generation of energy. However, coal extraction and its use constitute important pollution factors; thus, risk characterization and estimation are extremely important for the safety of coal workers and the environment. Candiota is located to the southeast of the state of Rio Grande do Sul and has the largest coal reserves in Brazil, and the largest thermal power complex in the state. In the open-cast mines, the coal miners are constantly exposed to coal dust. The human buccal micronucleus cytome (BMCyt) assay has been used widely to investigate biomarkers for DNA damage, cell death, and basal cell frequency in buccal cells. The aim of this study was to assess whether prolonged exposure to coal dust could lead to an increase in genomic instability, cell death, and frequency of basal cells using the BMCyt assay. In the analysis of epithelial cells, the exposed group (n = 41) presented with a significantly higher frequency of basal cells, micronuclei in basal and differentiated cells, and binucleated cells compared to the non-exposed group (n = 29). The exposed group showed a significantly lower frequency of condensed chromatin cells than the non-exposed group. However, we found no correlation between DNA damage and metal concentration in the blood of mine workers. DNA damage observed in the mine workers may be a consequence of oxidative damage resulting from exposure to coal residue mixtures. In addition, our findings confirm that the BMCyt assay can be used to identify occupational risk.

  7. Chromosomal damage and micronucleus induction by MP-124, a novel poly(ADP-ribose) polymerase-1 (PARP-1) inhibitor: Evidence for a non-DNA-reactive mode of action.

    PubMed

    Yamamura, Eiji; Muto, Shigeharu; Yamada, Katsuya; Sato, Yuko; Iwase, Yumiko; Uno, Yoshifumi

    2015-04-01

    MP-124, a novel poly(ADP-ribose) polymerase-1 (PARP-1) inhibitor that competes with the binding of the PARP substrate nicotinamide adenine dinucleotide (NAD), is being developed as a neuroprotective agent against acute ischemic stroke. MP-124 increased structural chromosomal aberration in CHL/IU cells, but showed negative results in the bacterial reverse mutation test, and the rat bone marrow micronucleus (MN) and the rat liver unscheduled DNA synthesis tests after the intravenous bolus injection. Thus, MP-124 did not appear to be direct-acting mutagen. Since, PARP-1 is a key enzyme in DNA repair, the effect of continuous PARP-1 inhibition by MP-124 was further examined in the rat MN test under 24-h intravenous infusion, and an increase in micronucleated immature erythrocytes (MNIE) was observed. The increase was clearly reduced by co-treatment with nicotinic acid, which resulted in increased intracellular NAD levels. This is consistent with the established activity of MP-124 as a competitive inhibitor of PARP and provides strong evidence that the DNA-damaging effect that leads to the increase in MNIE is a secondary effect of PARP-1 inhibition. This mechanism is expected to result in a threshold for the induction of MNIE by MP-124, and allows for the establishment of a safe margin of exposure for the therapeutic use of MP-124.

  8. In situ monitoring of urban air in Córdoba, Argentina using the Tradescantia-micronucleus (Trad-MCN) bioassay

    NASA Astrophysics Data System (ADS)

    Carreras, H. A.; Pignata, M. L.; Saldiva, P. H. N.

    During the last decades, a significant deterioration of ambient air quality has been observed in Argentina. However, the availability of air pollution monitoring stations is still limited to only few cities. In this study, we investigated the genotoxicity of ambient levels of air pollution in Córdoba using the Tradescantia micronucleus assay. The experiment was performed from October, 2004 to April 2005. Pots with Tradescantia pallida were placed in three sites: Córdoba city center, characterized by important avenues with high traffic activity (cars, taxis, and public transport vehicles); the university campus, along a side road with heavy traffic of gasoline and diesel powered vehicles, buses and trucks; and a residential area, with no significant local sources of air pollution. Twenty young T. pallida inflorescences were collected from each sampling site in November, February and April. Micronuclei frequencies were determined in early tetrads of pollen mother cells and expressed as MCN/100 tetrads. Simultaneously, the environmental levels of total suspended particles (24 h mean) were determined for each site. A significant difference in micronuclei frequency was observed among sites ( p=0.036). Post-hoc analysis revealed that the residential area exhibited a lower micronuclei frequency than the university and city center areas. In conclusion, we found that the gradients of ambient air pollution of Córdoba are associated with changes in the spontaneous micronuclei frequency of Tradescantia pollen mother cells. These results indicate that in situ biomonitoring with higher plants may be useful for characterizing air pollution in areas without instrumental monitoring techniques, or for exploring the distribution of air contaminants at a microscale.

  9. Genotoxicity assessment of soils from wastewater irrigation areas and bioremediation sites using the Vicia faba root tip micronucleus assay.

    PubMed

    Song, Y F; Gong, P; Wilke, B M; Zhang, W; Song, X Y; Sun, T H; Ackland, M L

    2007-02-01

    Genotoxicity potential of soils taken from wastewater irrigation areas and bioremediation sites was assessed using the Vicia faba root tip micronucleus assay. Twenty five soils were tested, of which 8 were uncontaminated soils and taken as the control to examine the influence of soil properties; 6 soils were obtained from paddy rice fields with a history of long-term wastewater irrigation; 6 soils were obtained from bioremediation sites to examine effects of bioremediation; and 5 PAH-contaminated soils were used to examine methodological effects between direct soil exposure and exposure to aqueous soil extracts on micronuclei (MN) frequency ( per thousand) in the V. faba root tips. Results indicate that soil properties had no significant influences on MN frequencies (p > 0.05) when soil pH varied between 3.4 to 7.6 and organic carbon between 0.4% and 18.6%. The MN frequency measured in these control soils ranged from 1.6 per thousand to 5.8 per thousand. MN frequencies in soils from wastewater irrigation areas showed 2- to 48-fold increase as compared with the control. Soils from bioremediation sites showed a mixed picture: MN frequencies in some soils decreased after bioremediation, possibly due to detoxification; whereas in other cases remediated soils induced higher MN frequencies, suggesting that genotoxic substances might be produced during bioremediation. Exposure to aqueous soil extracts gave a higher MN frequency than direct exposure in 3 soils. However, the opposite was observed in the other two soils, suggesting that both exposure routes should be tested in case of negative results from one route. Data obtained from this study indicate that the MN assay is a sensitive assay suitable for evaluating genotoxicity of soils.

  10. In situ assessment of pesticide genotoxicity in an integrated pest management program I--Tradescantia micronucleus assay.

    PubMed

    Rodrigues, G S; Pimentel, D; Weinstein, L H

    1998-02-13

    The genotoxicity induced by pesticides applied in an integrated pest management (IPM) program was evaluated with the Tradescantia micronucleus assay (Trad-MCN). Three pesticide application rates were prescribed as follows: (a) Low, no field pesticide spray; (b) Medium, IPM test rate: banded cyanazine plus metolachlor (2.7 kg a.i. and 2.3 l a.i./ha of herbicides, respectively); and (c) High, a preventative pesticide application program: broadcast cyanazine plus metolachlor (same application rates as above) plus chlorpyrifos (1 kg a.i./ha of insecticide). The Trad-MCN was employed for the assessment of (a) the formulated compounds, singly and in combinations; (b) pesticide residues extracted from soils sampled before and after application, and (c) in situ exposures (14-h exposure to pesticide-sprayed field). All pesticides showed clastogenic potency at doses between 10 and 50 ppm. Aqueous extracts of the two pesticide-sprayed soils were clastogenic, but the unsprayed soil extracts were not. Plants exposed in situ to pesticide-sprayed soils (inside a chamber receiving vapors from the soil) also showed significant increases in micronuclei frequency in relation to controls exposed to unsprayed soil. In general, there was no significant reduction in the genotoxic effects from the High to the Medium treatment levels of the IPM program. This suggests that the reduction in pesticide application rates attained with the implementation of the proposed IPM program was not sufficient to abate the genotoxicity of the pesticides, as perceived with the sensitive assays employed. The results indicate that replacing genotoxic compounds may be the only effective remediation measure to eliminate the risks imposed by mutagenic compounds in the agricultural environment.

  11. Increased micronucleus, nucleoplasmic bridge, and nuclear bud frequencies in the peripheral blood lymphocytes of diesel engine exhaust-exposed workers.

    PubMed

    Zhang, Xiao; Duan, Huawei; Gao, Feng; Li, Yuanyuan; Huang, Chuanfeng; Niu, Yong; Gao, Weimin; Yu, Shanfa; Zheng, Yuxin

    2015-02-01

    The International Agency for Research on Cancer has recently reclassified diesel engine exhaust (DEE) as a Group 1 carcinogen. Micronucleus (MN), nucleoplasmic bridge (NPB), and nuclear bud (NBUD) frequencies in peripheral blood lymphocytes (PBLs) are associated with cancer risk. However, the impact of DEE exposure on MN frequency has not been thoroughly elucidated due to mixed exposure and its impact on NPB and NBUD frequencies has never been explored in humans. We recruited 117 diesel engine testing workers with exclusive exposure to DEE and 112 non-DEE-exposed workers, and then we measured urinary levels of 4 mono-hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs) using high-performance liquid chromatography-mass spectrometry as well as MN, NPB, and NBUD frequencies in PBLs using cytokinesis-block MN assay. The DEE-exposed workers exhibited significantly higher MN, NPB, and NBUD frequencies than the non-DEE-exposed workers (P < 0.05). Among all study subjects, increasing levels of all 4 urinary OH-PAHs, on both quartile and continuous scales, were associated with increased MN, NPB, and NBUD frequencies (all P < 0.05). When the associations were analyzed separately in DEE-exposed and non-DEE-exposed workers, we found that the association between increasing quartiles of urinary 9-hydroxyphenanthrene (9-OHPh) and MN frequencies persisted in DEE-exposed workers (P = 0.001). The percent of MN frequencies increased, on average, by 23.99% (95% confidential interval, 9.64-39.93) per 1-unit increase in ln-transformed 9-OHPh. Our results clearly show that exposure to DEE can induce increases in MN, NPB, and NBUD frequencies in PBLs and suggest that DEE exposure level is associated with MN frequencies.

  12. Optimized automated data analysis for the cytokinesis‐block micronucleus assay using imaging flow cytometry for high throughput radiation biodosimetry

    PubMed Central

    Rodrigues, M. A.; Probst, C. E.; Beaton‐Green, L. A.

    2016-01-01

    Abstract The cytokinesis‐block micronucleus (CBMN) assay is a well‐established technique that can be employed in triage radiation biodosimetry to estimate whole body doses of radiation to potentially exposed individuals through quantitation of the frequency of micronuclei (MN) in binucleated lymphocyte cells (BNCs). The assay has been partially automated using traditional microscope‐based methods and most recently has been modified for application on the ImageStreamX (ISX) imaging flow cytometer. This modification has allowed for a similar number of BNCs to be automatically scored as compared to traditional microscopy in a much shorter time period. However, the MN frequency measured was much lower than both manual and automated slide‐based methods of performing the assay. This work describes the optimized analysis template which implements newly developed functions in the IDEAS® data analysis software for the ISX that enhances specificity for BNCs and increases the frequency of scored MN. A new dose response calibration curve is presented in which the average rate of MN per BNC is of similar magnitude to those presented in the literature using automated CBMN slide scoring methods. In addition, dose estimates were generated for nine irradiated, blinded samples and were found to be within ±0.5 Gy of the delivered dose. Results demonstrate that the improved identification accuracy for MN and BNCs in the ISX‐based version of the CBMN assay will translate to increased accuracy when estimating unknown radiation doses received by exposed individuals following large‐scale radiological or nuclear emergencies. © 2016 The Authors. Cytometry Part A published by Wiley Periodicals, Inc. on behalf of ISAC PMID:27272602

  13. Genotoxicity of Heterocyclic PAHs in the Micronucleus Assay with the Fish Liver Cell Line RTL-W1

    PubMed Central

    Brinkmann, Markus; Blenkle, Henning; Salowsky, Helena; Bluhm, Kerstin; Schiwy, Sabrina; Tiehm, Andreas; Hollert, Henner

    2014-01-01

    Heterocyclic aromatic hydrocarbons are, together with their un-substituted analogues, widely distributed throughout all environmental compartments. While fate and effects of homocyclic PAHs are well-understood, there are still data gaps concerning the ecotoxicology of heterocyclic PAHs: Only few publications are available investigating these substances using in vitro bioassays. Here, we present a study focusing on the identification and quantification of clastogenic and aneugenic effects in the micronucleus assay with the fish liver cell line RTL-W1 that was originally derived from rainbow trout (Oncorhynchus mykiss). Real concentrations of the test items after incubation without cells were determined to assess chemical losses due to, e.g., sorption or volatilization, by means of gas chromatography-mass spectrometry. We were able to show genotoxic effects for six compounds that have not been reported in vertebrate systems before. Out of the tested substances, 2,3-dimethylbenzofuran, benzothiophene, quinoline and 6-methylquinoline did not cause substantial induction of micronuclei in the cell line. Acridine caused the highest absolute induction. Carbazole, acridine and dibenzothiophene were the most potent substances compared with 4-nitroquinoline oxide, a well characterized genotoxicant with high potency used as standard. Dibenzofuran was positive in our investigation and tested negative before in a mammalian system. Chemical losses during incubation ranged from 29.3% (acridine) to 91.7% (benzofuran) and may be a confounding factor in studies without chemical analyses, leading to an underestimation of the real potency. The relative potency of the investigated substances was high compared with their un-substituted PAH analogues, only the latter being typically monitored as priority or indicator pollutants. Hetero-PAHs are widely distributed in the environment and even more mobile, e.g. in ground water, than homocyclic PAHs due to the higher water solubility. We

  14. Repeated dose liver micronucleus assay using adult mice with multiple genotoxicity assays concurrently performed as a combination test.

    PubMed

    Hagio, Soichiro; Furukawa, Satoshi; Abe, Masayoshi; Kuroda, Yusuke; Hayashi, Seigo; Ogawa, Izumi

    2014-06-01

    Recently, the liver micronucleus (MN) assay using young adult rats with repeated administrations has been investigated by employing a new method without partial hepatectomy or in situcollagenase perfusion as the repeated dose liver MN (RDLMN) assay by Narumi et al. (2012). In our study, in order to investigate the possibility of the RDLMN assay using young adult mice instead of rats and the feasibility of employing some genotoxicity assays along with the RDLMN assay as a combination test, two genotoxic carcinogens (N,N-diethylnitrosoamine (DEN) and cisplatin (CIS)) and a nongenotoxic carcinogen (phenobarbital sodium (PHE)) were administered to mice for 15 or 29 days. Then, the liver MN assay, peripheral blood (PB) MN assay and comet assay using the liver and kidney were concurrently performed as a combination test. DEN showed positive responses to all endpoints except MN induction in PB after 15 days of repeat administration. A cross-linking agent, CIS, showed MN induction in liver after 29 days of repeat administration, and in PB after 15 and 29 days of repeat administration, although the comet assay yielded negative responses for both organs at both sampling times. PHE yielded negative responses for all endpoints. In conclusion, it is suggested that the RDLMN assay using mice is a feasible method to be integrated into the general repeated toxicity test along with the combination assays, i.e., comet assay or PB MN assay, which would help in risk assessment for carcinogenicity by comparing the results of combination assays with each other.

  15. Effect of buprenorphine on genotoxicity evaluation of chemicals by the rat liver micronucleus test with partial hepatectomy.

    PubMed

    Itoh, Satoru; Nagata, Mayumi; Hattori, Chiharu; Takasaki, Wataru

    2015-02-01

    In the view of animal welfare considerations, we investigated the suitability of modifying the rat liver micronucleus test with partial hepatectomy to include administration of an analgesic drug to minimize pain and distress as much as possible. The effects of the analgesic, buprenorphine, on the genotoxicity evaluation of structural chromosome aberration inducers (cyclophosphamide, diethylnitrosamine and 1,2-dimethylhydrazine) and numerical chromosome aberration inducers (colchicine and carbendazim) were examined. The genotoxicants were given orally to 8-week-old male F344 rats a day before or after partial hepatectomy and hepatocytes were isolated 4 days after the partial hepatectomy. Buprenorphine was injected subcutaneously twice a day with at least a 6-hr interval for 2 days from just after partial hepatectomy. As results, buprenorphine caused neither change in clinical signs (except for one animal death) nor increase in the incidence of micronucleated hepatocytes of vehicle treated animals. In the case of concomitant treatment of buprenorphine and a genotoxicant, one out of 8 animals died in each group given buprenorphine with cyclophosphamide, carbendazim or colchicine (lower dose level only). Slight changes in clinical signs were noted in the group given buprenorphine with cyclophosphamide or carbendazim. A statistically significant increase in the incidence of micronucleated hepatocytes was obtained in concomitant treatment of buprenorphine and genotoxicant compared with genotoxicant alone for 1,2-dimethylhydrazine, colchicine and carbendazim. It is concluded that use of buprenorphine as an analgesic drug to minimize pain and distress for rats that are given partial hepatectomy is not appropriate under the present experimental conditions, because it could enhance the general toxicity and genotoxicity of the test chemical.

  16. Assessment of a twice dosing regimen both before and after partial hepatectomy in the rat liver micronucleus test.

    PubMed

    Itoh, Satoru; Igarashi, Miyuki; Nagata, Mayumi; Hattori, Chiharu

    2015-04-01

    The liver micronucleus test is an important method to detect in vivo genotoxicants, especially those that require metabolic activation for their genotoxicity. We have already reported that structural or numerical chromosome aberration inducers have to be given before or after partial hepatectomy, respectively, to detect their genotoxicity in the liver of rats. In the present study, we assessed a twice dosing regimen, in which the genotoxicant is dosed both before and after partial hepatectomy, using the four chromosome aberration inducers used in the previous study. Two structural chromosome aberration inducers (diethylnitrosamine and 1,2-dimethylhydrazine) and two numerical chromosome aberration inducers (colchicine and carbendazim) were used. The genotoxicant was administered to 8-week old male F344 rats one day before and again one day after the partial hepatectomy and hepatocytes were isolated 3 days after second dosing (4 days after the partial hepatectomy). As a result, all genotoxicants (structural or numerical chromosome aberration inducers) caused a dose-dependent statistically significant increase in the incidence of micronucleated hepatocytes when given both before and after partial hepatectomy. No marked difference was observed in general toxicity, relative liver weight and cell classification between single dosing regimens and twice dosing regimen of the genotoxicants. These results confirm that the twice dosing regimen, in which the test compound is dosed both before and after partial hepatectomy, can detect in vivo induction of micronucleated hepatocytes by structural or numerical chromosome aberration inducers qualitatively similar to their appropriate regimen in which the test compound is administered either before or after partial hepatectomy.

  17. Characterization of the particulate matter and relationship between buccal micronucleus and urinary 1-hydroxypyrene levels among cashew nut roasting workers.

    PubMed

    de Oliveira Galvão, Marcos Felipe; de Queiroz, Jana Dara Freires; Duarte, Ediclê de Souza Fernandes; Hoelzemann, Judith Johanna; de André, Paulo Afonso; Saldiva, Paulo Hilário Nascimento; Menezes Filho, José Antônio; Batistuzzo de Medeiros, Silvia Regina

    2017-01-01

    The present study is the first assessment of occupational risk associated with artisanal cashew nut roasting using exposure and effect biomarkers, as well as a characterization and dispersion analysis of the released particulate matter (PM). A real-time particle monitor was used to quantify PM1.0, PM2.5 and PM10. Furthermore, the PM was sampled using a Handi-vol sampler, and the physicochemical characteristics were determined by SEM-EDS analysis. Trajectories, dispersion and deposition of the emitted material were calculated using the NOAA-HYSPLIT model. Urinary 1-hydroxypyrene (1-OHP) levels were analyzed by HPLC. DNA damage, chromosomal instability and cell death were measured by a buccal micronucleus cytome assay (BMCyt). The PM concentrations for all measurements in the exposed area were higher than in the non-exposed area. SEM-EDS analyses exhibited a wide variety of particles, and K, Cl, S and Ca biomass burning tracers were the major inorganic compounds. In addition, atmospheric modeling analysis suggested that these particles can reach regions farther away than 40 kilometers. Occupational polycyclic aromatic hydrocarbon exposure was confirmed by increases in 1-OHP levels in cashew nut workers. Frequencies of BMCyt biomarkers of genotoxicity (micronuclei and nuclear bud) and cytotoxicity (pyknosis, karyolysis, karyorrhexis and condensed chromatin) were higher in the exposed group compared with the controls. The influence of factors, such as age, on the micronuclei frequencies was demonstrated, and a correlation between 1-OHP and micronuclei was observed. To the best of our knowledge, no other study has demonstrated a correlation between these types of biomarkers. The use of exposure (1-OHP) and effect (BMCyt) biomarkers were therefore efficient in assessing the occupational risk associated with artisanal cashew nut roasting, and the high rates of PM2.5 are considered to be a potential contributor to this effect.

  18. Evaluation of drinking water treatment combined filter backwash water recycling technology based on comet and micronucleus assay.

    PubMed

    Chen, Ting; Xu, Yongpeng; Liu, Zhiquan; Zhu, Shijun; Shi, Wenxin; Cui, Fuyi

    2016-04-01

    Based on the fact that recycling of combined filter backwash water (CFBW) directly to drinking water treatment plants (WTP) is considered to be a feasible method to enhance pollutant removal efficiency, we were motivated to evaluate the genotoxicity of water samples from two pilot-scale drinking water treatment systems, one with recycling of combined backwash water, the other one with a conventional process. An integrated approach of the comet and micronucleus (MN) assays was used with zebrafish (Danio rerio) to investigate the water genotoxicity in this study. The total organic carbon (TOC), dissolved organic carbon (DOC), and trihalomethane formation potential (THMFP), of the recycling process were lower than that of the conventional process. All the results showed that there was no statistically significant difference (P>0.05) between the conventional and recycling processes, and indicated that the genotoxicity of water samples from the recycling process did not accumulate in 15 day continuous recycling trial. It was worth noting that there was correlation between the concentrations of TOC, DOC, UV254, and THMFPs in water and the DNA damage score, with corresponding R(2) values of 0.68, 0.63, 0.28, and 0.64. Nevertheless, both DNA strand breaks and MN frequency of all water samples after disinfection were higher than that of water samples from the two treatment units, which meant that the disinfection by-products (DBPs) formed by disinfection could increase the DNA damage. Both the comet and MN tests suggest that the recycling process did not increase the genotoxicity risk, compared to the traditional process.

  19. Combination comet/micronucleus assay validation performed by BioReliance under the JaCVAM initiative.

    PubMed

    Pant, Kamala; Krsmanovic, Ljubica; Bruce, Shannon Wilson; Kelley, Tawney; Arevalo, Mirna; Atta-Safoh, Samuel; Debelie, Fekadu; La Force, Michelle L Klug; Springer, Sandra; Sly, Jamie; Paranjpe, Madhav; Lawlor, Timothy; Aardema, Marilyn

    2015-07-01

    In the international validation study of the in vivo rat alkaline comet assay (comet assay), the Japanese Center for the Validation of Alternative Methods (JaCVAM) provided three coded chemicals to BioReliance, 1,3-dichloropropene, ethionamide and busulfan, to be tested in a combined in vivo comet/micronucleus assay. Induction of DNA damage (comet) in liver, stomach and jejunum (1,3-dichloropropene only) cells, and induction of MNPCEs in bone marrow, were examined in male Sprague-Dawley (Hsd:SD) rats following oral administration of the test chemical for three consecutive days. A dose range finding (DRF) test was performed with each chemical to determine the maximum tolerated dose (MTD). Based on the results of the DRF test; 1,3-dichloropropene was tested at 50, 100 and 200 mg/kg/day; ethionamide was tested at 125, 250 and 500 mg/kg/day, and busulfan was tested at 10, 20 and 40 mg/kg/day. The results indicated that 1,3-dichloropropene induced DNA damage only in liver cells at all three test article doses, while no effects were observed in the stomach and jejunum cells. Additionally, it did not increase MNPCEs in the bone marrow. 1,3-Dichloropropene was concluded to be negative in the MN assay but positive in the comet assay. Ethionamide did not induce DNA damage in liver. However, in stomach, statistically significant decreases (although still within historical range) in % tail DNA at all test article doses compared to the vehicle control were observed. There was no increase in MNPCEs in the bone marrow. Thus, ethionamide was concluded to be negative in the comet/MN combined assay. Busulfan did not induce DNA damage in any of the organs tested (liver and stomach) but it did induce a significant increase in MNPCEs in the bone marrow. Busulfan was concluded to be negative in the comet assay but positive in the MN assay.

  20. Cytogenetic status of healthy children assessed with the alkaline comet assay and the cytokinesis-block micronucleus cytome assay.

    PubMed

    Gajski, Goran; Gerić, Marko; Oreščanin, Višnja; Garaj-Vrhovac, Vera

    2013-01-20

    In the present study the alkaline comet assay and the cytokinesis-block micronucleus cytome (CBMN Cyt) assay were used to evaluate the baseline frequency of cytogenetic damage in peripheral blood lymphocytes (PBLs) of 50 healthy children from the general population in Croatia (age, 11.62±1.81 years). Mean values of tail length, tail intensity and tail moment, as comet assay parameters, were 12.92±0.10, 0.73±0.06 and 0.08±0.01, respectively. The mean frequency of micronuclei (MN) for all subjects was 2.32±0.28 per 1000 bi-nucleated cells, while the mean frequency of nucleoplasmic bridges (NPBs) was 1.72±0.24 and of nuclear buds (NBUDs) 1.44±0.19. The mean nuclear division index (NDI) was 1.70±0.05. When comet-assay parameters were considered, higher mean values for all three were found for the female population. According to the Mann-Whitney U test applied on the results of the comet assay, the only statistically significant difference between the male and female populations was found for tail length. Similar to the results obtained by the comet assay, girls showed higher mean values of all three measured parameters of the CBMN Cyt assay. This difference was statistically significant for total number of NPBs only. In the case of the NDI, a higher mean value was also obtained in girls, but this difference was not statistically significant. The results obtained present background data that could be considered as normal values for healthy children living in urban areas, and can later on serve as baseline values for further toxicological monitoring. Additionally, the usefulness of both techniques in measuring cytogenetic damage during bio-monitoring of children is confirmed.

  1. Recent advances in in vivo genotoxicity testing: prediction of carcinogenic potential using comet and micronucleus assay in animal models.

    PubMed

    Kang, Seung Hun; Kwon, Jee Young; Lee, Jong Kwon; Seo, Young Rok

    2013-12-01

    Genotoxic events have been known as crucial step in the initiation of cancer. To assess the risk of cancer, genotoxicity assays, including comet, micronucleus (MN), chromosomal aberration, bacterial reverse, and sister chromatid exchange assay, can be performed. Compared with in vitro genotoxicity assay, in vivo genotoxicity assay has been used to verify in vitro assay result and definitely provide biological significance for certain organs or cell types. The comet assay can detect DNA strand breaks as markers of genotoxicity. Methods of the in vivo comet assay have been established by Japanese Center for the Validation of Alternative Methods (JaCVAM) validation studies depending on tissue and sample types. The MN can be initiated by segregation error and lagging acentric chromosome fragment. Methods of the in vivo MN assay have been established by Organization for Economic Co-operation and Development (OECD) test guidelines and many studies. Combining the in vivo comet and MN assay has been regarded as useful methodology for evaluating genetic damage, and it has been used in the assessment of potential carcinogenicity by complementarily presenting two distinct endpoints of the in vivo genotoxicity individual test. Few studies have investigated the quantitative relation between in vivo genotoxicity results and carcinogenicity. Extensive studies emphasizes that positive correlation is detectable. This review summarizes the results of the in vivo comet and MN assays that have investigated the genotoxicity of carcinogens as classified by the International Agency for Research on Cancer (IARC) carcinogenicity database. As a result, these genotoxicity data may provide meaningful information for the assessment of potential carcinogenicity and for implementation in the prevention of cancer.

  2. Genetic toxicity evaluation of iodotrifluoromethane (Cf{sub 3}I). Volume 2. Results of in vivo mouse bone marrow erythrocyte micronucleus testing. Final report, March-December 1994

    SciTech Connect

    Mitchell, A.D.

    1995-01-01

    Under subcontract to ManTech Environmental Technology, Incorporated, Genesys Research, Incorporated, examined the potential of odotrifluoromethane (CF3I) to induce structural chromosomes aberrations in erythropoietic cells of the bone marrow. Genesys used the mouse micronucleus test which measures the clastogenic (chromosomes breaking) action of chemicals by the induction of micronuclei in bone marrow cells, as observed in erythrocytes from the peripheral blood of male and female mice obtained approximately 24 hours after steady-state dosing. Based on preliminary toxicity information obtained by ManTech, a mouse bone marrow micronucleus test of CF3I was conducted using 2.6, 5.0, and 7.5% CF3I administered to male and female Swiss Webster mice by inhalation for six hours on each of three consecutive days. Bone marrow cells were obtained from the mice sacrificed 24 hours after the third exposure. Erythrocytes from mice exposed to the test material, and to the negative and positive controls, were evaluated for toxicity and the presence of micronuclei. The positive control, 0.4 mg triethylenemelamine (TEM)/kg (administered intraperitonealy) significantly (pmicronucleus test and clastogenic in vivo.

  3. A semi-automated FISH-based micronucleus-centromere assay for biomonitoring of hospital workers exposed to low doses of ionizing radiation

    PubMed Central

    VRAL, ANNE; DECORTE, VEERLE; DEPUYDT, JULIE; WAMBERSIE, ANDRÉ; THIERENS, HUBERT

    2016-01-01

    The aim of the present study was to perform cytogenetic analysis by means of a semi-automated micro-nucleus-centromere assay in lymphocytes from medical radiation workers. Two groups of workers receiving the highest occupational doses were selected: 10 nuclear medicine technicians and 10 interventional radiologists/cardiologists. Centromere-negative micronucleus (MNCM−) data, obtained from these two groups of medical radiation workers were compared with those obtained in matched controls. The blood samples of the matched controls were additionally used to construct a 'low-dose' (0–100 mGy) MNCM− dose-response curve to evaluate the sensitivity and suitability of the micronucleus-centromere assay as an 'effect' biomarker in medical surveillance programs. The physical dosimetry data of the 3 years preceding the blood sampling, based on single or double dosimetry practices, were collected for the interpretation of the micronucleus data. The in vitro radiation results showed that for small sized groups, semi-automated scoring of MNCM− enables the detection of a dose of 50 mGy. The comparison of MNCM− yields in medical radiation workers and control individuals showed enhanced MNCM− scores in the medical radiation workers group (P=0.15). The highest MNCM− scores were obtained in the interventional radiologists/cardiologists group, and these scores were significantly higher compared with those obtained from the matched control group (P=0.05). The higher MNCM− scores observed in interventional radiologists/cardiologists compared with nuclear medicine technicians were not in agreement with the personal dosimetry records in both groups, which may point to the limitation of 'double dosimetry' procedures used in interventional radiology/cardiology. In conclusion, the data obtained in the present study supports the importance of cytogenetic analysis, in addition to physical dosimetry, as a routine biomonitoring method in medical radiation workers receiving the

  4. Changes in buccal micronucleus cytome parameters associated with smokeless tobacco and pesticide exposure among female tea garden workers of Assam, India.

    PubMed

    Kausar, Afifa; Giri, Sarbani; Roy, Prasenjit; Giri, Anirudha

    2014-03-01

    Assam is the highest tea producing state in India. A large number of workers are engaged in various units of tea industry. There are few reports on the health status of the tea garden workers. The present cytogenetic biomonitoring study was undertaken to investigate the genotoxic effect associated with workers in tea industries in southern Assam. Smokeless tobacco chewing along with betel nut is very common practice among the workers. Workers also get exposed periodically to mixture of pesticides. Employing buccal micronucleus cytome assay, exfoliated buccal cells were analyzed in 90 female tea garden and compared to 90 age and sex matched non-chewer control as well as 70 chewers who are not tea garden workers. Statistically significant (p<0.001) increase in genotoxic and cell death parameters was observed in tea garden workers compared to both the control groups. The frequency of cell proliferation biomarkers was highest in the chewer controls whereas genotoxic and cell death parameters were highest in tea garden workers. Linear correlation analysis revealed strong positive correlation between the duration of occupation and the frequency of micronucleus (r=0.597; p<0.001) as well as cell death parameters (r=0.588; p<0.001). Amount of chewing also had significant positive correlation with micronucleus frequency (r=0.243 or 5.9%; p<0.05) and cell death parameters (r=0.217; p<0.05). A statistically significant decrease in total RBC count, haemoglobin content as well as acetylcholine esterase in the blood of exposed individuals was observed. The average BMI among the tea garden workers was relatively lower compared to the control group. Pesticide exposure and chewing areca nut along with smokeless tobacco use may be responsible for changes in cytome parameters in exfoliated buccal cells.

  5. Low-LET and high-LET radiation action of {sup 125}I decays in DNA: Effect of cysteamine on micronucleus formation and cell killing

    SciTech Connect

    Hofer, K.G.; Bao, S.P.

    1995-02-01

    Chinese hamster ovary cells were pulse-labeled with {sup 125}I-iododeoxyuridine during early S phase, and cell samples were harvested 30 min or 5 h after labeling. The samples were frozen (with or without 25 mM cysteamine) and stored at -196{degrees}C for accumulation of {sup 125}I decays. X-ray control experiments were performed at 37{degrees}C and -196{degrees}C. Aliquots of cells were plated for evaluating micronucleus formation and cell survival. The results demonstrated a striking shift in micronucleus formation and cell death with time after labeling. Cells frozen 30 min after labeling exhibited effects typical of low-LET radiation, but cells frozen 5 h after labeling showed a response characteristic of high-LET radiation. Cysteamine provided protection against the effects of {sup 125}I during the initial phase of effects characteristic of low-LET radiation, but no protection was seen during the phase characteristic of high-LET radiation. When cell survival was evaluated as a function of micronucleus frequency rather than dose in decays/cell, the survival curves for all treatment groups became superimposed. Previous work using the same experimental system had failed to show a direct link between {sup 125}I-induced DNA double-strand breaks and cell death. These findings are consistent with the hypothesis that DNA damage may not be the sole mechanism for cell killing and that damage to higher-order structures in the cell nucleus may contribute to (or modify) radiation-induced cell death. 50 refs., 7 figs.

  6. Cytosine arabinoside, vinblastine, 5-fluorouracil and 2-aminoanthracene testing in the in vitro micronucleus assay with L5178Y mouse lymphoma cells at Sanofi Aventis, with different cytotoxicity measurements, in support of the draft OECD Test Guideline on In Vitro Mammalian Cell Micronucleus Test.

    PubMed

    Cariou, Olivier; Laroche-Prigent, Nathalie; Ledieu, Sandrine; Guizon, Isabelle; Paillard, Françoise; Thybaud, Véronique

    2010-10-29

    Cytosine arabinoside (a nucleoside analogue that inhibits the gap-filling step of excision repair), vinblastine (an aneugen that inhibits tubulin polymerisation), 5-fluorouracil (a nucleoside analogue with a steep response profile), and 2-aminoanthracene (a metabolism-dependent reference genotoxin) were tested in the in vitro micronucleus assay with L5178Y mouse lymphoma cells, without cytokinesis block. The four chemicals were independently evaluated in two Sanofi Aventis laboratories, one of which used an image analyser to score micronuclei, while the other scored micronucleated cells manually. Very similar results were obtained in the two laboratories, highlighting the robustness of the assay. The four test chemicals induced significant increases in the incidence of micronucleated cells at concentrations that produced no more than a 55±5% reduction in survival growth, as measured with the three parameters recommended in the draft OECD Test Guideline on In Vitro Mammalian Cell Micronucleus Test (MNvit) for chemical testing, namely the relative increase in cell counts, relative population doubling, and the relative cell count. These results support the premise that the relative increase in cell counts and relative population doubling, that take into account both cell death and cytostasis, are appropriate measures of survival growth reduction in the in vitro micronucleus test conducted in the absence of cytokinesis block, as recommended in MNvit.

  7. Can Spirulina maxima reduce the mutagenic potential of sibutramine?

    PubMed

    Araldi, R P; Santos, N P; Mendes, T B; Carvalho, L B; Ito, E T; de-Sá-Júnior, P L; Souza, E B

    2015-12-28

    The worldwide obesity pandemic requires the use of anti-obesity drugs. Sibutramine is an anti-obesity drug that has been used worldwide but is indiscriminately consumed in Brazil. Several studies have demonstrated that sibutramine promotes weight loss and weight maintenance, but several side effects have been associated with its systematic consumption. For this reason, sibutramine was withdrawn from the European and American markets, but still remains legal for use in Brazil. Studies have shown that a 5-10% reduction in body weight results in outstanding health benefits for obese patients. However, in order to promote significant weight loss, it is necessary to use sibutramine for at least 2 years. This long-term exposure has carcinogenic potential, as sibutramine causes DNA damage. Thus, this study evaluated the in vivo mutagenic potential of sibutramine alone (5, 7, 10, 15, and 20 mg/kg) and in association with Spirulina maxima (150 and 300 mg/kg), a cyanobacterium with antioxidant potential, using the polychromatic erythrocyte micronucleus test. Our results reinforced the mutagenic potential of sibutramine alone, which showed a time-dependent action. Combinatory treatments with S. maxima were not able to reduce the genotoxicity of sibutramine. These results were confirmed in vitro with the cytokinesis-blocked micronucleus test. In conclusion, our data showed that new alternative anti-obesity treatments are needed since the consumption of sibutramine can increase the risk of cancer in overweight patients.

  8. Effects of β-glucan polysaccharide revealed by the dominant lethal assay and micronucleus assays, and reproductive performance of male mice exposed to cyclophosphamide.

    PubMed

    Oliveira, Rodrigo Juliano; Pesarini, João Renato; Sparça Salles, Maria José; Nakamura Kanno, Tatiane Yumi; Dos Santos Lourenço, Ana Carolina; da Silva Leite, Véssia; da Silva, Ariane Fernanda; Matiazi, Hevenilton José; Ribeiro, Lúcia Regina; Mantovani, Mário Sérgio

    2014-03-01

    β-glucan is a well-known polysaccharide for its chemopreventive effect. This study aimed to evaluate the chemopreventive ability of β-glucan in somatic and germ cells through the dominant lethal and micronucleus assays, and its influence on the reproductive performance of male mice exposed to cyclophosphamide. The results indicate that β-glucan is capable of preventing changes in DNA in both germ cells and somatic ones. Changes in germ cells were evaluated by the dominant lethal assay and showed damage reduction percentages of 46.46% and 43.79% for the doses of 100 and 150 mg/kg. For the somatic changes, evaluated by micronucleus assay in peripheral blood cells in the first week of treatment, damage reduction percentages from 80.63-116.32% were found. In the fifth and sixth weeks, the percentage ranged from 10.20-52.54% and -0.95-62.35%, respectively. Besides the chemopreventive efficiency it appears that the β-glucan, when combined with cyclophosphamide, is able to improve the reproductive performance of males verified by the significant reduction in rates of post-implantation losses and reabsorption in the mating of nulliparous females with males treated with cyclophosphamide.

  9. In situ biomonitoring of the genotoxic effects of vehicular pollution in Uberlândia, Brazil, using a Tradescantia micronucleus assay.

    PubMed

    Pereira, Boscolli Barbosa; Campos Júnior, Edimar Olegário de; Morelli, Sandra

    2013-01-01

    The growing number of cars in large cities is directly linked to changes in the chemical composition of urban air, which has increasingly high concentrations of potentially genotoxic chemicals. Therefore, discovering and monitoring the risks associated with exposure to atmospheric pollutants is indispensible for preventing environmental and health problems. Because of the lack of reliable data regarding the air quality in the city of Uberlândia, the present study sought to test whether the genotoxic risks in areas with different levels of vehicular traffic can be measured using the Tradescantia micronucleus assay (Trad-MN). Therefore, more than twenty inflorescences were exposed to locations with different amounts of vehicular traffic twice per year from the winter of 2006 to the summer of 2011. The inflorescences were then analysed to determine the micronucleus (MN) frequency. In addition, we sought to determine the influence of factors linked to city climate on the MN frequencies obtained at each monitored location. Our results show that, although low relative humidity positively influenced MN formation in Tradescantia pallida tetrads, the major determining factor for clastogenic events was the level of vehicular traffic at the locations monitored over the five-year study.

  10. Increased micronucleus, nucleoplasmic bridge, nuclear bud frequency and oxidative DNA damage associated with prolactin levels and pituitary adenoma diameters in patients with prolactinoma.

    PubMed

    Bitgen, N; Donmez-Altuntas, H; Bayram, F; Cakir, I; Hamurcu, Z; Diri, H; Baskol, G; Senol, S; Durak, A C

    2016-01-01

    Prolactinoma is the most common pituitary tumor. Most pituitary tumors are benign, but they often are clinically significant. We investigated cytokinesis-block micronucleus cytome (CBMN cyt) assay parameters and oxidative DNA damage in patients with prolactinoma to assess the relations among age, prolactin level, pituitary adenoma diameter and 8-hydroxy-2'-deoxyguanosine (8-OHdG) level in patients with prolactinoma. We investigated 27 patients diagnosed with prolactinoma and 20 age- and sex-matched healthy controls. We measured CBMN cyt parameters and plasma 8-OHdG levels in peripheral blood lymphocytes of patients with prolactinoma and controls. The frequencies of micronucleus (MN), nucleoplasmic bridge, nuclear bud, apoptotic and necrotic cells, and plasma 8-OHdG levels in patients with prolactinoma were significantly greater than controls. MN frequency was correlated positively with age, prolactin levels and pituitary adenoma diameters in patients with prolactinoma. The increased chromosomal and oxidative DNA damage, and the positive correlation between MN frequency, prolactin levels and pituitary adenoma diameters may be associated with increased risk of cancer in patients with prolactinoma, because increased MN frequency is a predictor of cancer risk.

  11. Response of human lymphocytes to proton radiation of 60 MeV compared to 250 kV X-rays by the cytokinesis-block micronucleus assay.

    PubMed

    Miszczyk, Justyna; Rawojć, Kamila; Panek, Agnieszka; Swakoń, Jan; Prasanna, Pataje G; Rydygier, Marzena

    2015-04-01

    Particle radiotherapy such as protons provides a new promising treatment modality to cancer. However, studies on its efficacy and risks are relatively sparse. Using the cytokinesis-blocked micronucleus assay, we characterized response of human peripheral blood lymphocytes, obtained from health donors irradiated in vitro in the dose range: 0-4. 0 Gy, to therapeutic proton radiation of 60 MeV from AIC-144 isochronous cyclotron, by studying nuclear division index and DNA damage and compared them with X-rays. Peripheral blood lymphocytes show decreased ability to proliferate with increasing radiation doses for both radiation types, however, in contrast to X-rays, irradiation with protons resulted in a higher proliferation index at lower doses of 0.75 and 1.0 Gy. Protons are more effective in producing MN at doses above 1.75 Gy compared to X-rays. Dose-response curves for micronucleus incidence can be best described by a cubic model for protons, while for X-rays the response was linear. The differences in the energy spectrum and intracellular distribution of energy between radiation types are also apparent at the intracellular distribution of cytogenetic damage as seen by the distribution of various numbers of micronuclei in binucleated cells. Our studies, although preliminary, further contribute to the understanding of the mechanistic differences in the response of HPBL in terms of cellular proliferation and cytogenetic damage induced by protons and X-rays as well as intra-cellular distribution of energy and thus radiobiological effectiveness.

  12. Genotoxicity evaluation of benzene, di(2-ethylhexyl) phthalate, and trisodium ethylenediamine tetraacetic acid monohydrate using a combined rat comet/micronucleus assays.

    PubMed

    Kitamoto, Sachiko; Matsuyama, Ryoko; Uematsu, Yasuaki; Ogata, Keiko; Ota, Mika; Yamada, Toru; Miyata, Kaori; Kimura, Juki; Funabashi, Hitoshi; Saito, Koichi

    2015-07-01

    As a part of the Japanese Center for the Validation of Alternative Methods (JaCVAM)-initiative international validation study of the in vivo alkaline comet assay (comet assay), we examined DNA damage in the liver, stomach, and bone marrow of rats dosed orally three times with up to 2000 mg/kg of benzene, di(2-ethylhexyl) phthalate, and trisodium ethylenediamine tetraacetic acid monohydrate. All three compounds gave negative results in the liver and stomach. In addition, a bone marrow comet and micronucleus analysis revealed that benzene, but not di(2-ethylhexyl) phthalate or trisodium ethylenediamine tetraacetic acid monohydrate induced a significant increase in the median % tail DNA and micronucleated polychromatic erythrocytes, compared with the respective concurrent vehicle control. These results were in good agreement with the previously reported genotoxicity findings for each compound. The present study has shown that combining the micronucleus test with the comet assay and carrying out these analyses simultaneously is effective in clarifying the mechanism of action of genotoxic compounds such as benzene.

  13. Lack of genotoxic effect of food dyes amaranth, sunset yellow and tartrazine and their metabolites in the gut micronucleus assay in mice.

    PubMed

    Poul, Martine; Jarry, Gérard; Elhkim, Mostafa Ould; Poul, Jean-Michel

    2009-02-01

    The food dyes amaranth, sunset yellow and tartrazine were administered twice, at 24h intervals, by oral gavage to mice and assessed in the in vivo gut micronucleus test for genotoxic effects (frequency of micronucleated cells) and toxicity (apoptotic and mitotic cells). The concentrations of each compound and their main metabolites (sulfanilic acid and naphthionic acid) were measured in faeces during a 24-h period after single oral administrations of the food dyes to mice. Parent dye compounds and their main aromatic amine metabolites were detected in significant amounts in the environment of colonic cells. Acute oral exposure to food dye additives amaranth, sunset yellow and tartrazine did not induce genotoxic effect in the micronucleus gut assay in mice at doses up to 2000 mg/kg b.w. Food dyes administration increased the mitotic cells at all dose levels when compared to controls. These results suggest that the transient DNA damages previously observed in the colon of mice treated by amaranth and tartrazine by the in vivo comet assay [Sasaki, Y.F., Kawaguchi, S., Kamaya, A., Ohshita, M., Kabasawa, K., Iwama, K., Taniguchi, K., Tsuda, S., 2002. The comet assay with 8 mouse organs: results with 39 currently used food additives. Mutat. Res. 519, 103-119] are unable to be fixed in stable genotoxic lesions and might be partly explained by local cytotoxicity of the dyes.

  14. Application of dosimetry systems and cytogenetic status of the child population exposed to diagnostic X-rays by use of the cytokinesis-block micronucleus cytome assay.

    PubMed

    Gajski, Goran; Milković, Durđica; Ranogajec-Komor, Mária; Miljanić, Saveta; Garaj-Vrhovac, Vera

    2011-10-01

    Low-dose ionizing radiation used for medical purposes is one of the definite risk factors for cancer development, and children exposed to ionizing radiation are at a relatively greater cancer risk as they have more rapidly dividing cells than adults and have longer life expectancy. Since cytokinesis-block micronucleus cytome (CBMN Cyt) assay has become one of the standard endpoints for radiation biological dosimetry, we used that assay in the present work for the assessment of different types of chromosomal damage in children exposed to diagnostic X-ray procedures. Twenty children all with pulmonary diseases between the ages of 4 and 14 years (11.30 ± 2.74) were evaluated. Absorbed dose measurements were conducted for posterior-anterior projection on the forehead, thyroid gland, gonads, chest and back. Doses were measured using thermoluminescence and radiophotoluminescent dosimetry systems. It was shown that, after diagnostic X-rays, the mean total number of CBMN Cyt assay parameters (micronucleus, nucleoplasmic bridges and nuclear buds) was significantly higher than prior to diagnostic procedure and that interindividual differences existed for each monitored child. For the nuclear division index counted prior and after examination, no significant differences were noted among mean group values. These data suggest that even low-dose diagnostic X-ray exposure may induce damaging effect in the somatic DNA of exposed children, indicating that immense care should be given in both minimizing and optimizing radiation exposure to diminish the radiation burden, especially in the youngest population.

  15. In silico exploratory study using structure-activity relationship models and metabolic information for prediction of mutagenicity based on the Ames test and rodent micronucleus assay.

    PubMed

    Kamath, P; Raitano, G; Fernández, A; Rallo, R; Benfenati, E

    2015-12-01

    The mutagenic potential of chemicals is a cause of growing concern, due to the possible impact on human health. In this paper we have developed a knowledge-based approach, combining information from structure-activity relationship (SAR) and metabolic triggers generated from the metabolic fate of chemicals in biological systems for prediction of mutagenicity in vitro based on the Ames test and in vivo based on the rodent micronucleus assay. In the first part of the work, a model was developed, which comprises newly generated SAR rules and a set of metabolic triggers. These SAR rules and metabolic triggers were further externally validated to predict mutagenicity in vitro, with metabolic triggers being used only to predict mutagenicity of chemicals, which were predicted unknown, by SARpy. Hence, this model has a higher accuracy than the SAR model, with an accuracy of 89% for the training set and 75% for the external validation set. Subsequently, the results of the second part of this work enlist a set of metabolic triggers for prediction of mutagenicity in vivo, based on the rodent micronucleus assay. Finally, the results of the third part enlist a list of metabolic triggers to find similarities and differences in the mutagenic response of chemicals in vitro and in vivo.

  16. Applicability and robustness of the hen's egg test for analysis of micronucleus induction (HET-MN): results from an inter-laboratory trial.

    PubMed

    Greywe, Daniela; Kreutz, Jürgen; Banduhn, Norbert; Krauledat, Matthias; Scheel, Julia; Schroeder, Klaus R; Wolf, Thorsten; Reisinger, Kerstin

    2012-08-30

    The hen's egg test for analysis of micronucleus formation (HET-MN) was developed several years ago to provide an alternative test system to the in vivo micronucleus test. In order to assess its applicability and robustness, a study was carried out at the University of Osnabrueck (lab A) and at the laboratories of Henkel AG & Co. KGaA (lab B). Following transfer of the method to lab B, a range of test substances that had been pre-tested at lab A, were tested at Henkel: the genotoxins cyclophosphamide, dimethylbenz(a)anthracene, methotrexate, acrylamide, azorubin, N-nitroso-dimethylamine and the non-genotoxins, orange G and isopropyl myristate. In a second phase, additional compounds with known in vivo properties were examined in both labs: the non-genotoxin, ampicillin, the "irrelevant" positives, isophorone and 2,4-dichlorophenol ("irrelevant" means positive in standard in vitro tests, but negative in vivo), the clastogen p-chloroaniline, and the aneugens carbendazim and vinorelbine. All substances were correctly predicted in both labs with respect to their in vivo genotoxic properties, indicating that the HET-MN may have an improved predictivity compared with current standard in vitro test systems. The results support the promising role of the HET-MN assay as a supplement to existing test batteries.

  17. The EpiDerm™ 3D human reconstructed skin micronucleus (RSMN) assay: Historical control data and proof of principle studies for mechanistic assay adaptations.

    PubMed

    Roy, Shambhu; Kulkarni, Rohan; Hewitt, Nicola J; Aardema, Marilyn J

    2016-07-01

    The in vitro human reconstructed skin micronucleus (RSMN) assay in EpiDerm™ is a promising novel animal alternative for evaluating genotoxicity of topically applied chemicals. It is particularly useful for assessing cosmetic ingredients that can no longer be tested using in vivo assays. To advance the use of this test especially for regulatory decision-making, we have established the RSMN assay in our laboratory according to Good Laboratory Practice and following the principles of the OECD test guideline 487 in vitro mammalian cell micronucleus test. Proficiency with the assay was established by correctly identifying direct-acting genotoxins and genotoxins requiring metabolism, as well as non-genotoxic/non-carcinogenic chemicals. We also report the analysis of our historical control data that demonstrate vehicle control and positive control values for %micronuclei in binucleated cells are in the ranges reported previously. Technical issues including evaluating various solvents with both 48h and 72h treatment regimens were investigated. For the first time, mechanistic studies using CREST analysis revealed that the RSMN assay is suitable for distinguishing aneugens and clastogens. Moreover, the assay is also suitable for measuring cytokines as markers for proliferative and toxic effects of chemicals.

  18. Effects of β-glucan polysaccharide revealed by the dominant lethal assay and micronucleus assays, and reproductive performance of male mice exposed to cyclophosphamide

    PubMed Central

    Oliveira, Rodrigo Juliano; Pesarini, João Renato; Sparça Salles, Maria José; Nakamura Kanno, Tatiane Yumi; dos Santos Lourenço, Ana Carolina; da Silva Leite, Véssia; da Silva, Ariane Fernanda; Matiazi, Hevenilton José; Ribeiro, Lúcia Regina; Mantovani, Mário Sérgio

    2014-01-01

    β-glucan is a well-known polysaccharide for its chemopreventive effect. This study aimed to evaluate the chemopreventive ability of β-glucan in somatic and germ cells through the dominant lethal and micronucleus assays, and its influence on the reproductive performance of male mice exposed to cyclophosphamide. The results indicate that β-glucan is capable of preventing changes in DNA in both germ cells and somatic ones. Changes in germ cells were evaluated by the dominant lethal assay and showed damage reduction percentages of 46.46% and 43.79% for the doses of 100 and 150 mg/kg. For the somatic changes, evaluated by micronucleus assay in peripheral blood cells in the first week of treatment, damage reduction percentages from 80.63–116.32% were found. In the fifth and sixth weeks, the percentage ranged from 10.20–52.54% and −0.95–62.35%, respectively. Besides the chemopreventive efficiency it appears that the β-glucan, when combined with cyclophosphamide, is able to improve the reproductive performance of males verified by the significant reduction in rates of post-implantation losses and reabsorption in the mating of nulliparous females with males treated with cyclophosphamide. PMID:24688298

  19. Application of the micronucleus test and comet assay in Trachemys callirostris erythrocytes as a model for in situ genotoxic monitoring.

    PubMed

    Zapata, Lina M; Bock, Brian C; Orozco, Luz Yaneth; Palacio, Jaime A

    2016-05-01

    Trachemys callirostris is a turtle species endemic to northern South America. In northern Colombia it occurs in the middle and lower Magdalena River drainage and its principal tributaries (lower Cauca and San Jorge rivers) and in other minor drainages such as the lower Sinú River. In recent years, industrial, agricultural, and mining activities have altered natural habitats in Colombia where this species occurs, and many of the pollutants released there are known to induce genetic alterations in wildlife species. The micronucleus test and comet assay are two of the most widely used methods to characterize DNA damage induced by physical and chemical agents in wildlife species, but have not been employed previously for genotoxic evaluations in T. callirostris. The goal of this study was to optimize these genotoxic biomarkers for T. callirostris erythrocytes in order to establish levels of DNA damage in this species and thereby evaluate its potential as a sentinel species for monitoring genotoxic effects in freshwater environments in northern Colombia. Both genotoxic techniques were applied on peripheral blood erythrocytes from 20 captive-reared T. callirostris individuals as a negative control, as well as from samples obtained from 49 individuals collected in Magangué (Magdalena River drainage) and 24 individuals collected in Lorica (Sinú River drainage) in northern Colombia. Negative control individuals exhibited a baseline frequency of micronuclei of 0.78±0.58 and baseline values for comet tail length and tail moment of 3.34±0.24µm and 10.70±5.5, respectively. In contrast, samples from both field sites exhibited significantly greater evidence of genotoxic effects for both tests. The mean MN frequencies in the samples from Magangué and Lorica were 8.04±7.08 and 12.19±12.94, respectively. The mean tail length for samples from Magangué and Lorica were 5.78±3.18 and 15.46±7.39, respectively. Finally, the mean tail moment for samples from Magangué and

  20. Assessment of the genotoxic, antigenotoxic, and cytotoxic activities of the ethanolic fruit extract of Solanum lycocarpum A. St. Hill. (Solanaceae) by micronucleus test in mice.

    PubMed

    Vieira, Pabline Marinho; Costa, Paula Moiana da; Ribeiro e Silva, Carolina; Chen-Chen, Lee

    2010-12-01

    Solanum lycocarpum A. St. Hill. (Family Solanaceae), popularly known in Brazil as lobeira, is a common weed in the Brazilian Cerrado vegetation. The fruits of this species have been used in Brazil for culinary purposes and in folk medicine as a sedative, diuretic, antiepileptic, antispasmodic, hypoglycemic, and hypocholesterolemic agent as well as in the control of obesity. Due to the spreading use of this plant as a therapeutic resource and food, the present study aimed to evaluate the genotoxic, antigenotoxic, and cytotoxic effects of S. lycocarpum ethanolic fruit extract using the mouse bone marrow micronucleus test. Both genotoxicity and antigenotoxicity of this ethanolic fruit extract were evaluated by using the frequency of micronucleated polychromatic erythrocytes, whereas cytotoxicity was assessed by the polychromatic and normochromatic erythrocytes ratio. Our results indicated that although S. lycocarpum ethanolic fruit extract did not exhibit genotoxic effect in mice bone marrow, both cytotoxic and antigenotoxic actions were evidenced at all tested doses.

  1. A Review on Mutagenicity Testing for Hazard Classification of Chemicals at Work: Focusing on in vivo Micronucleus Test for Allyl Chloride.

    PubMed

    Rim, Kyung-Taek; Kim, Soo-Jin

    2015-09-01

    Chemical mutagenicity is a major hazard that is important to workers' health. Despite the use of large amounts of allyl chloride, the available mutagenicity data for this chemical remains controversial. To clarify the mutagenicity of allyl chloride and because a micronucleus (MN) test had not yet been conducted, we screened for MN induction by using male ICR mice bone marrow cells. The test results indicated that this chemical is not mutagenic under the test conditions. In this paper, the regulatory test battery and several assay combinations used to determine the genotoxic potential of chemicals in the workplace have been described. Further application of these assays may prove useful in future development strategies of hazard evaluations of industrial chemicals. This study also should help to improve the testing of this chemical by commonly used mutagenicity testing methods and investigations on the underlying mechanisms and could be applicable for workers' health.

  2. Genotoxicity testing of the herbicide Roundup and its active ingredient glyphosate isopropylamine using the mouse bone marrow micronucleus test, Salmonella mutagenicity test, and Allium anaphase-telophase test.

    PubMed

    Rank, J; Jensen, A G; Skov, B; Pedersen, L H; Jensen, K

    1993-06-01

    The genotoxic potential of the herbicide Roundup and its active agent, glyphosate isopropylamine salt, was studied in three different assays. No clastogenic effects were found in the mouse bone marrow micronucleus test for either of the two agents. In the Salmonella assay only Roundup was tested. It showed a weak mutagenic effect for the concentrations 360 micrograms/plate in TA98 (without S9) and 720 micrograms/plate in TA100 (with S9). These concentrations are close to the toxic level. The anaphase-telophase Allium test showed no effect for the glyphosate isopropylamine salt, but a significant increase in chromosome aberrations appeared after treatment with Roundup at concentrations of 1.44 and 2.88 mg/l when calculated as glyphosate isopropylamine. The most frequent aberrations observed could be characterized as disturbances of the spindle.

  3. Influence of GSTs, CYP2E1 and mEH polymorphisms on 1, 3-butadiene-induced micronucleus frequency in Chinese workers

    SciTech Connect

    Tan Hongshan; Wang Qi; Wang Aihong; Ye Yunjie; Feng Nannan; Feng Xiaoqing; Lu Lingeng; Au, William; Zheng Yuxin; Xia Zhaolin

    2010-09-15

    1,3-butadiene (BD) has been classified as a human carcinogen, however, the relationship between chromosomal damage and its metabolic polymorphisms is not clear. The present study used the CBMN assay to detect chromosomal damage in the peripheral lymphocytes of 166 exposed workers and 41 non-exposed healthy individuals. PCR and PCR-RFLP were applied to detect GSTT1, GSTM1, CYP2E1 c1c2 and mEH Tyr113His, His139Arg polymorphisms. The results demonstrated that the micronucleus (MN) frequency of the exposed workers was significantly higher than controls (P < 0.01). Among the exposed workers, the individuals with high BD exposures are more susceptible to chromosomal damage than those with low exposures (FR = 1.30, 95% CI 1.14-1.53; P < 0.05). Gender-difference was also found in our study: males got lower micronucleus frequency than females. Workers who carried the genotypes of GSTM1 (+), CYP2E1 (c1c2/c2c2) and mEH intermediate (I) group had significantly higher MN frequency than those carrying the genotypes of GSTM1 (-) (FR = 1.29, 95% CI 1.05-1.59; P < 0.05), CYP2E1 (c1c1) (FR = 1.55, 95% CI 1.24-1.93; P < 0.01) or mEH high (H) group (FR = 1.57, 95% CI 1.08-2.34; P < 0.05), respectively. Our data indicated that the current BD exposure level could cause significantly higher MN frequency in workers than controls. Polymorphisms of GSTM1, CYP2E1 and mEH are susceptible to altered chromosome damage.

  4. Comparative genotoxicity of nanosilver in human liver HepG2 and colon Caco2 cells evaluated by fluorescent microscopy of cytochalasin B-blocked micronucleus formation.

    PubMed

    Sahu, Saura C; Roy, Shambhu; Zheng, Jiwen; Yourick, Jeffrey J; Sprando, Robert L

    2014-11-01

    As a consequence of the increased use of silver nanoparticles in food, food contact materials, dietary supplements and cosmetics to prevent fungal and bacterial growth, there is a need for validated rapid screening methods to assess the safety of nanoparticle exposure. This study evaluated two widely used in vitro cell culture models, human liver HepG2 cells and human colon Caco2 cells, as tools for assessing the potential genotoxicity of 20-nm nanosilver. The average silver nanoparticle size as determined by transmission electron microscopy (TEM) was 20.4 nm. Dynamic light scattering (DLS) analysis showed no large agglomeration of the silver nanoparticles. The silver concentration in a 20-nm nanosilver solution determined by the inductively coupled plasma-mass spectrometry (ICP-MS) analysis was 0.962 mg ml(-1) . Analysis by ICP-MS and TEM demonstrated the uptake of 20-nm silver by both HepG2 and Caco2 cells. Genotoxicity was determined by the cytochalasin B-blocked micronucleus assay with acridine orange staining and fluorescence microscopy. Concentration- and time-dependent increases in the frequency of binucleated cells with micronuclei induced by the nanosilver was observed in the concentration range of 0.5 to 15 µg ml(-1) in both HepG2 and Caco2 cells compared with the control. Our results indicated that HepG2 cells were more sensitive than Caco2 cells in terms of micronuclei formation induced by nanosilver exposure. In summary, the results of this study indicate that the widely used in vitro models, HepG2 and Caco2 cells in culture, represent potential screening models for prediction of genotoxicity of silver nanoparticles by in vitro micronucleus assay.

  5. Evaluation of the genotoxicity and cytotoxicity of filling pastes used for pulp therapy on deciduous teeth using the micronucleus test on bone marrow from mice (Mus musculus).

    PubMed

    Santos, Nilton C N; Ramos, Maria E S P; Ramos, Aline F B; Cerqueira, Adriana B; Cerqueira, Eneida M M

    2016-09-01

    Pulp therapy is the last resort for preserving deciduous teeth. However, the genotoxic and cytotoxic effects of many products used in this therapy are not well established. The aim of this study was to use the micronucleus test on bone marrow from mice to evaluate the genotoxic and cytotoxic effects of four filling pastes: zinc oxide, calcium hydroxide P.A., mineral trioxide aggregate and an iodoform paste (iodoform + camphorated + paramonochlorophenol + rifamycin + prednisolone). Male Swiss mice were divided into 4 groups of 10 animals, each exposed to one of the pastes, and were subdivided according to the dilutions tested: 1/10, 1/50, 1/500 and 1/1000 administered intraperitoneally (0.1ml/10g of weight). Cyclophosphamide was the positive control. The negative controls were dimethylsulfoxide and buffered saline solution. Five animals were killed 24h and five 48h after the treatment. The material was processed in accordance with Schmid (1976) and micronuclei were counted in 1000 polychromatic erythrocytes (PCE), under an optical microscope in a blinded test. Cytotoxicity was evaluated using the PCE/normochromatic erythrocyte (NCE) ratio in 200 erythrocytes. The micronucleus analysis results were evaluated using the conditional test for comparing proportions in situations of rare events. Analysis of variance and Tukey's test were used to evaluate the PCE/NCE ratio. There was significantly greater occurrence of micronuclei in the animals treated with iodoform paste at all the dilutions tested, at both sacrifice times. Greater occurrence of micronuclei was observed among the animals treated with zinc oxide and sacrificed 48h after the treatment, at the dilutions 1:50; 1:500 and 1:1000. Calcium hydroxide P.A. and mineral trioxide aggregate did not present any genotoxic or cytotoxic effects. The genotoxicity and cytotoxicity of zinc oxide and iodoform paste revealed here constitute an initial step towards their contraindication, but additional studies will be necessary

  6. Alkaline comet assay in liver and stomach, and micronucleus assay in bone marrow, from rats treated with 2-acetylaminofluorene, azidothymidine, cisplatin, or isobutyraldehyde.

    PubMed

    Kraynak, A R; Barnum, J E; Cunningham, C L; Ng, A; Ykoruk, B A; Bennet, B; Stoffregen, D; Merschman, M; Freeland, E; Galloway, S M

    2015-07-01

    As part of the Japanese Center for the Validation of Alternative Methods (JaCVAM) initiative international validation study of the in vivo rat alkaline comet assay (comet assay), we examined the ability of the assay to determine the genotoxicity of 2-acetylaminofluorene (AAF), azidothymidine (AZT), cisplatin (CPN), and isobutyraldehyde (IBA) in liver and glandular stomach of male Sprague-Dawley rats. Rats were given oral doses of test compound or control once daily for three days. High dose levels were approximately maximum tolerated doses and were based on preliminary range-finding studies. Tissues were harvested 3h after the final dose (48h after the initial dose). A bone marrow micronucleus assay (MN) was also conducted on the rats treated with AZT, CPN, and IBA. Acute toxic effects of treatment were determined primarily through histomorphologic analysis of liver and stomach but also by body weight and serum liver enzyme changes. The comet assay was conducted on fresh tissue preparations but frozen samples from two studies were also assayed. Statistically significant dose-related differences in comet % DNA in tail were found in liver and stomach for the genotoxin AZT and in liver for the genotoxin CPN, but not in liver or stomach for the non-genotoxin IBA. Statistically significant differences in % DNA in tail were measured in liver for the low and mid dose of the genotoxin AAF, but not the high dose. The comet assays of frozen liver suspensions from CPN- and AAF-treated rats yielded comparable results to the assays of fresh preparations. There were no indications of significant toxicity induced by any treatment. The micronucleus assay was positive for CPN and AZT and negative for IBA. In conclusion, the in vivo comet assay is capable of detecting genotoxic effects of a variety of chemicals and may fill an important role in the genotoxicity test battery.

  7. Evaluation of the repeated-dose liver micronucleus assay using N-nitrosomorpholine in young adult rats: report on collaborative study by the Collaborative Study Group for the Micronucleus Test (CSGMT)/Japanese Environmental Mutagen Society (JEMS)-Mammalian Mutagenicity Study (MMS) Group.

    PubMed

    Hayashi, Aya; Kosaka, Mizuki; Kimura, Aoi; Wako, Yumi; Kawasako, Kazufumi; Hamada, Shuichi

    2015-03-01

    The present study was conducted to evaluate the suitability of a repeated-dose liver micronucleus (LMN) assay in young adult rats as a collaborative study by the Mammalian mutagenicity study (MMS) group. All procedures were performed in accordance with the standard protocols of the MMS Group. Six-week-old male Crl:CD(SD) rats (5 animals/group) received oral doses of the hepatocarcinogen N-nitrosomorpholine (NMOR) at 0 (control), 5, 10, and 30mg/kg/day (10mL/kg) for 14 days. Control animals received vehicle (water). Hepatocytes were collected from the liver 24h after the last dose, and the number of micronucleated hepatocytes (MNHEPs) was determined by microscopy. The number of micronucleated immature erythrocytes (MNIMEs) in the femoral bone marrow was also determined. The liver was examined using histopathologic methods after formalin fixation. The results showed statistically significant and dose-dependent increases in the number of MNHEPs in the liver at doses of 10mg/kg and greater when compared with the vehicle control. However, no significant increase was noted in the number of MNIMEs in the bone marrow at doses of up to 30mg/kg. Histopathology of the liver revealed hypertrophy and single cell necrosis of hepatocytes at doses of 5mg/kg and above. These results showed that the induction of micronuclei by NMOR was detected by the repeated-dose LMN assay, but not by the repeated-dose bone marrow micronucleus assay.

  8. Cytosine arabinoside, vinblastine, diethylstilboestrol and 2-aminoanthracene tested in the in vitro human TK6 cell line micronucleus test (MNvit) at Institut Pasteur de Lille in support of OECD draft test guideline 487.

    PubMed

    Nesslany, Fabrice; Marzin, Daniel

    2010-10-29

    The reference genotoxic agents Cytosine arabinoside, Vinblastine, Diethylstilboestrol and 2-Aminoanthracene were tested in the in vitro micronucleus assay, in human lymphoblastoid TK6 cells, without cytokinesis block, at the laboratories of Institut Pasteur de Lille, France. This was done in support of the toxicity measures recommended in the late 2007 version of the draft OECD Test Guideline 487 for the testing of chemicals. All four reference agents were positive in the assay at concentrations giving approximately 50% toxicity or less as assessed by draft Test Guideline 487 recommended measures, relative population doublings and relative increase in cell counts. Accordingly, this work supports the premise that relative population doublings and relative increase in cell counts are appropriate measures of toxicity for the non-cytokinesis blocked in vitro micronucleus assay.

  9. Cadmium chloride, benzo[a]pyrene and cyclophosphamide tested in the in vitro mammalian cell micronucleus test (MNvit) in the human lymphoblastoid cell line TK6 at Covance laboratories, Harrogate UK in support of OECD draft Test Guideline 487.

    PubMed

    Fowler, Paul; Whitwell, James; Jeffrey, Laura; Young, Jamie; Smith, Katie; Kirkland, David

    2010-10-29

    The following genotoxic chemicals were tested in the in vitro micronucleus assay, at Covance Laboratories, Harrogate, UK in the human lymphoblastoid cell line TK6. Cadmium chloride (an inorganic carcinogen), benzo[a]pyrene (a polycyclic aromatic hydrocarbon requiring metabolic activation) and cyclophosphamide (an alkylating agent requiring metabolic activation) were treated with and without cytokinesis block (by addition of cytochalasin B). This work formed part of a collaborative evaluation of the toxicity measures recommended in the draft OECD Test Guideline 487 for the in vitro micronucleus test. The toxicity measures used, capable of detecting both cytostasis and cell death, were relative population doubling, relative increase in cell counts and relative cell counts for treatments in the absence of cytokinesis block, and replication index or cytokinesis blocked proliferation index in the presence of cytokinesis block. All of the chemicals tested gave significant increases in the percentage of micronucleated cells with and without cytokinesis block at concentrations giving approximately 60% toxicity (cytostasis and cell death) or less by all of the toxicity measures used. The outcomes from this series of tests support the use of relative increase in cell counts and relative population doubling, as well as relative cell counts, as appropriate measures of cytotoxicity for the non-cytokinesis blocked in the in vitro micronucleus assay.

  10. Mitomycin C, 5-fluoruracil, colchicine and etoposide tested in the in vitro mammalian cell micronucleus test (MNvit) in the human lymphoblastoid cell line TK6 at Novartis in support of OECD draft Test Guideline 487.

    PubMed

    Elhajouji, Azeddine

    2010-10-29

    The following reference genotoxic agents were tested in the in vitro micronucleus test, at Novartis, Basel, Switzerland. Mitomycin C, 5-fluoruracil, colchicine and etoposide were tested in the human lymphoblastoid cell line TK6, with and without cytokinesis block (in the presence of cytochalasin B). This was done in support of the toxicity measures recommended in the draft OECD Test Guideline on In Vitro Mammalian Cell Micronucleus Test (MNvit) and was part of an international collaborative work. As toxicity measures, detecting cytostasis and cell death, relative cell counts (RCC), relative increase in cell counts (RICC), and relative population doubling (RPD) were used for treatments in the absence of cytokinesis block, and replication index (RI) or cytokinesis-blocked proliferation in the presence of cytokinesis block. All four reference agents were positive in the assay with and without cytokinesis block at concentrations giving approximately 50% toxicity or less as assessed by all of the toxicity measures used. Accordingly, the results of this work support the use of relative population doubling and relative increase in cell counts, as well as relative cell counts, as appropriate measures of toxicity for the non-cytokinesis-blocked in vitro micronucleus assay.

  11. Etoposide; colchicine; mitomycin C and cyclophosphamide tested in the in vitro mammalian cell micronucleus test (MNvit) in Chinese hamster lung (CHL) cells at Covance laboratories; Harrogate UK in support of OECD draft Test Guideline 487.

    PubMed

    Fowler, Paul; Whitwell, James; Jeffrey, Laura; Young, Jamie; Smith, Katie; Kirkland, David

    2010-10-29

    The following genotoxic chemicals were tested in the in vitro micronucleus assay, at Covance Laboratories, Harrogate, UK in the Chinese hamster lung cell line CHL. Etoposide (a topoisomerase inhibitor), colchicine (an aneugen), mitomycin C (a DNA cross linking agent) and cyclophosphamide (an alkylating agent requiring metabolic activation) were treated with and without cytokinesis block (by addition of cytochalasin B). This work formed part of a collaborative evaluation of the toxicity measures recommended in the draft OECD Test Guideline 487 for the in vitro micronucleus test. The toxicity measures used, detecting both cytostasis and cell death, were relative population doubling, relative increase in cell counts and relative cell counts for treatments in the absence of cytokinesis block, and replication index or cytokinesis blocked proliferation index in the presence of cytokinesis block. All of the chemicals tested gave significant increases in the percentage of micronucleated cells with and without cytokinesis block at concentrations giving approximately 60% toxicity (cytostasis and cell death) or less by all of the toxicity measures used. The outcomes from this series of tests support the use of relative increase in cell counts and relative population doubling, as well as relative cell counts, as appropriate measures of cytotoxicity for the non-cytokinesis blocked in vitro micronucleus assay.

  12. Comparative study of the comet assay and the micronucleus test in amphibian larvae (Xenopus laevis) using benzo(a)pyrene, ethyl methanesulfonate, and methyl methanesulfonate: establishment of a positive control in the amphibian comet assay.

    PubMed

    Mouchet, F; Gauthier, L; Mailhes, C; Ferrier, V; Devaux, A

    2005-02-01

    The present investigation explored the potential use of the comet assay (CA) as a genotoxicity test in the amphibian Xenopus laevis and compared it with the French standard micronucleus test (MNT). Benzo[a]pyrene (B[a]P), methyl methanesulfonate (MMS), and ethyl methanesulfonate (EMS) were used as model compounds for assessing DNA damage. Damage levels were measured as DNA strand breaks after alkaline electrophoresis of nuclei isolated from larval amphibian erythrocytes using the CA in order to establish a positive control for further ecotoxicological investigations. The results led to the selection of MMS as a positive control on the basis of the higher sensitivity of Xenopus laevis to this compound. The CA and MNT were compared for their ability to detect DNA damage with the doses of chemical agents and exposure times applied. EMS and MMS were shown to increase micronucleus and DNA strand break formation in larval erythrocytes concurrently. However, B[a]P increased micronucleus formation but not that of DNA strand breaks. Time-dose experiments over 12 days of exposure suggest that the CA provides an earlier significant response to genotoxicants than does the MNT. In Xenopus the CA appears to be a sensitive and suitable method for detecting genotoxicity like that caused by EMS and MMS. It can be considered a genotoxicity-screening tool. The results for B[a]P show that both tests should be used in a complementary manner on Xenopus.

  13. Evaluation of the repeated-dose liver and gastrointestinal tract micronucleus assays with 22 chemicals using young adult rats: summary of the collaborative study by the Collaborative Study Group for the Micronucleus Test (CSGMT)/The Japanese Environmental Mutagen Society (JEMS) - Mammalian Mutagenicity Study Group (MMS).

    PubMed

    Hamada, Shuichi; Ohyama, Wakako; Takashima, Rie; Shimada, Keisuke; Matsumoto, Kazumi; Kawakami, Satoru; Uno, Fuyumi; Sui, Hajime; Shimada, Yasushi; Imamura, Tadashi; Matsumura, Shoji; Sanada, Hisakazu; Inoue, Kenji; Muto, Shigeharu; Ogawa, Izumi; Hayashi, Aya; Takayanagi, Tomomi; Ogiwara, Yosuke; Maeda, Akihisa; Okada, Emiko; Terashima, Yukari; Takasawa, Hironao; Narumi, Kazunori; Wako, Yumi; Kawasako, Kazufumi; Sano, Masaki; Ohashi, Nobuyuki; Morita, Takeshi; Kojima, Hajime; Honma, Masamitsu; Hayashi, Makoto

    2015-03-01

    The repeated-dose liver micronucleus (RDLMN) assay using young adult rats has the potential to detect hepatocarcinogens. We conducted a collaborative study to assess the performance of this assay and to evaluate the possibility of integrating it into general toxicological studies. Twenty-four testing laboratories belonging to the Mammalian Mutagenicity Study Group, a subgroup of the Japanese Environmental Mutagen Society, participated in this trial. Twenty-two model chemicals, including some hepatocarcinogens, were tested in 14- and/or 28-day RDLMN assays. As a result, 14 out of the 16 hepatocarcinogens were positive, including 9 genotoxic hepatocarcinogens, which were reported negative in the bone marrow/peripheral blood micronucleus (MN) assay by a single treatment. These outcomes show the high sensitivity of the RDLMN assay to hepatocarcinogens. Regarding the specificity, 4 out of the 6 non-liver targeted genotoxic carcinogens gave negative responses. This shows the high organ specificity of the RDLMN assay. In addition to the RDLMN assay, we simultaneously conducted gastrointestinal tract MN assays using 6 of the above carcinogens as an optional trial of the collaborative study. The MN assay using the glandular stomach, which is the first contact site of the test chemical when administered by oral gavage, was able to detect chromosomal aberrations with 3 test chemicals including a stomach-targeted carcinogen. The treatment regime was the 14- and/or 28-day repeated-dose, and the regime is sufficiently promising to incorporate these methods into repeated-dose toxicological studies. The outcomes of our collaborative study indicated that the new techniques to detect chromosomal aberrations in vivo in several tissues worked successfully.

  14. Peripheral blood lymphocyte micronucleus frequencies in men from areas of Kerala, India, with high vs normal levels of natural background ionizing radiation.

    PubMed

    Karuppasamy, C V; Ramachandran, E N; Kumar, V Anil; Kumar, P R Vivek; Koya, P K M; Jaikrishan, G; Das, Birajalaxmi

    2016-04-01

    We have measured the frequencies of micronuclei (MN) in adult male individuals living in areas of the Kerala coast, southwest India, with either high (HLNRA, >1.5mGy/year) or normal levels of natural ionizing radiation (NLNRA, ≤1.5mGy/year). Blood samples were obtained from 141 individuals, 94 from HLNRA and 47 from NLNRA, aged 18-72, and were subjected to the cytokinesis-block micronucleus (CBMN) assay. An average of 1835 binucleated (BN) cells per individual were scored. The overall frequency of MN (mean±SD) was 11.7±6.7 per 1000 BN cells. The frequencies of MN in the HLNRA (11.7±6.6) and NLNRA (11.6±6.7) were not statistically significantly different (P=0.59). However, a statistically significant (P<0.001) age-dependent increase in MN frequency was observed among individuals from both HLNRA and NLNRA. No natural background radiation dose-dependent increase in MN frequency was seen. MN frequency was not influenced by tobacco smoking or chewing but it was increased among individuals consuming alcohol. Chronic low-dose radiation in the Kerala coast did not have a significant effect on MN frequency among adult men.

  15. Performance of flow cytometric analysis for the micronucleus assay--a reconstruction model using serial dilutions of malaria-infected cells with normal mouse peripheral blood.

    PubMed

    Torous, Dorothea; Asano, Norihide; Tometsko, Carol; Sugunan, Siva; Dertinger, Stephen; Morita, Takeshi; Hayashi, Makoto

    2006-01-01

    To confirm the performance and statistical power of a flow cytometric method for scoring micronucleated erythrocytes, reconstruction experiments were performed. For these investigations, peripheral blood erythrocytes from untreated mice, with a micronucleated erythrocyte frequency of approximately 0.1% were combined with known quantities of Plasmodium berghei (malaria) infected mouse erythrocytes. These cells had an infected erythrocyte frequency of approximately 0.7%, and mimic the DNA content of micronuclei (MN). For an initial experiment, samples with a range of MN/malaria (Mal) content were constructed and analysed in triplicate by flow cytometry until 2000, 20,000 and 200,000 total erythrocytes were acquired. In a second experiment, each specimen was analysed in triplicate until 2000, 20,000, 200,000 and 1,000,000 erythrocytes were acquired. As expected, the sensitivity of the assay to detect small changes in rare erythrocyte sub-population frequencies was directly related to the number of cells analysed. For example, when 2000 cells were scored, increases in MN/Mal frequencies of 3.9- or 2.7-fold were detected as statistically significant. When 200,000 cells were analysed, a 1.2-fold increase was detected. These data have implications for the experimental design and interpretation of micronucleus assays that are based on automated scoring procedures, since previously unattainable numbers of cells can now be readily scored.

  16. Genotoxic and Antigenotoxic Assessment of Chios Mastic Oil by the In Vitro Micronucleus Test on Human Lymphocytes and the In Vivo Wing Somatic Test on Drosophila

    PubMed Central

    Vlastos, Dimitris; Drosopoulou, Elena; Efthimiou, Ioanna; Gavriilidis, Maximos; Panagaki, Dimitra; Mpatziou, Krystalenia; Kalamara, Paraskevi; Mademtzoglou, Despoina; Mavragani-Tsipidou, Penelope

    2015-01-01

    Chios mastic oil (CMO), the essential oil derived from Pistacia lentiscus (L.) var. chia (Duham), has generated considerable interest because of its antimicrobial, anticancer, antioxidant and other beneficial properties. In the present study, the potential genotoxic activity of CMO as well as its antigenotoxic properties against the mutagenic agent mitomycin-C (MMC) were evaluated by employing the in vitro Cytokinesis Block MicroNucleus (CBMN) assay and the in vivo Somatic Mutation And Recombination Test (SMART). In the in vitro experiments, lymphocytes were treated with 0.01, 0.05 and 0.10% (v/v) of CMO with or without 0.05 μg/ml MMC, while in the in vivo assay Drosophila larvae were fed with 0.05, 0.10, 0.50 and 1.00% (v/v) of CMO with or without 2.50 μg/ml MMC. CMO did not significantly increase the frequency of micronuclei (MN) or total wing spots, indicating lack of mutagenic or recombinogenic activity. However, the in vitro analysis suggested cytotoxic activity of CMO. The simultaneous administration of MMC with CMO did not alter considerably the frequencies of MMC-induced MN and wing spots showing that CMO doesn’t exert antigenotoxic or antirecombinogenic action. Therefore, CMO could be considered as a safe product in terms of genotoxic potential. Even though it could not afford any protection against DNA damage, at least under our experimental conditions, its cytotoxic potential could be of interest. PMID:26110900

  17. Micronucleus frequency in copper-mine workers exposed to arsenic is modulated by the AS3MT Met287Thr polymorphism.

    PubMed

    Hernández, Alba; Paiva, Leiliane; Creus, Amadeu; Quinteros, Domingo; Marcos, Ricard

    2014-01-01

    Arsenic(III)methyltransferase (AS3MT) has been demonstrated to be the key enzyme in the metabolism of arsenic as it catalyses the methylation of arsenite and monomethylarsonic acid (MMA) to form methylated arsenic species, which have higher toxic and genotoxic potential than the parent compounds. The aim of this study is to evaluate if genetic variation in the AS3MT gene influences arsenic-induced cytogenetic damage, measured by the micronucleus (MN) assay. AS3MT Met287Thr allele frequencies and MN values were determined for 207 subjects working in the copper-mine industry, who were exposed to variable levels of arsenic. The urinary arsenic profile was used as individual biomarker of arsenic exposure. Results indicate that the MN frequencies found in peripheral blood lymphocytes of the exposed population poorly correlate with the levels of total arsenic content in urine. Nevertheless, when workers were classified according to their AS3MT Met287Thr genotypes, significantly higher MN values were observed for those carrying the variant allele [odds ratio (OR), 3.4 (1.6-5.2); P=0.0003)]. To our knowledge, these results are the first to show that genetic variation in AS3MT, especially the Met287Thr polymorphism, may play a role in modulating the levels of arsenic-induced cytogenetic damage among individuals chronically exposed to arsenic.

  18. Biomonitoring air quality during and after a public transportation strike in the center of Uberlândia, Minas Gerais, Brazil by Tradescantia micronucleus bioassay.

    PubMed

    Pereira, Boscolli Barbosa; de Campos, Edimar Olegário; de Lima, Euclides Antônio Pereira; Barrozo, Marcos Antonio Souza; Morelli, Sandra

    2014-03-01

    The aim of this study was to address the lack of information concerning the air quality in the city of Uberlândia, Minas Gerais, Brazil. In this study, we conducted an unprecedented experiment involving the in situ biomonitoring of air genotoxicity in the city center during and after a public transportation strike using the Tradescantia micronucleus test. The frequency of micronuclei was significantly higher in the city center compared with the reference site (Mann-Whitney test, p < 0.05), with the highest MN levels being observed during public transport stoppage (Kruskal-Wallis, Dunn p < 0.01). In addition, the multiple linear regression analyses revealed that the low circulation of buses during public transport stoppage and the increase in the concentration of particulate matter from the increased flow of vehicles in the city center during the strike positively influenced the MN frequency. The climatic factors did not change during the biomonitoring period, reflecting the fact that climatic factors did not influence the MN frequency.

  19. The synthetic food colouring agent Allura Red AC (E129) is not genotoxic in a flow cytometry-based micronucleus assay in vivo.

    PubMed

    Abramsson-Zetterberg, Lilianne; Ilbäck, Nils-Gunnar

    2013-09-01

    The safety of several azo colouring agents, used as food additives, has during the years been questioned. Allura Red AC (E129) has in some publications been classified as genotoxic. In fact, in the European Union, Allura Red is permitted as a food additive in human food, but, surprisingly, it was not acceptable as an additive for use in animal feed. In this study we have evaluated whether Allura Red is genotoxic using a flow cytometer-based micronucleus assay in peripheral blood of mice. Male FVB mice were given a single intra-peritoneal injection of various doses of Allura Red and sacrificed at 46 h after treatment. The tested doses were 0, 100, 200, 400, 600, 800, 1000, 1500, and 2000 mg/kg body weight (b.w.). Each dose group constituted three mice, except for in the dose group of 1000 mg/kg b. w., which constituted four mice. Blood samples were collected and the frequency of micronucleated polychromatic erythrocytes (fMNPCE) and the cell proliferation (%PCE) was determined. The analyses did not show any significant difference in the %PCE or in the fMNPCE. Consequently, under the testing circumstances one can conclude that Allura Red is not genotoxic.

  20. Human urothelial micronucleus assay to assess genotoxic recovery by reduction of arsenic in drinking water: a cohort study in West Bengal, India.

    PubMed

    Paul, Somnath; Bhattacharjee, Pritha; Mishra, Prafulla K; Chatterjee, Debmita; Biswas, Anirban; Deb, Debasree; Ghosh, Aloke; Mazumder, D N Guha; Giri, Ashok K

    2013-10-01

    Chronic exposure to arsenic through drinking water affects nearly 26 million individuals in West Bengal, India. Cytogenetic biomarkers like urothelial micronucleus (MN) are extensively used to monitor arsenic exposed population. In 2004-2005, 145 arsenic exposed individuals and 60 unexposed controls were surveyed of which 128 exposed individuals and 54 unexposed controls could be followed up in 2010-2011. In 2004-2005, the extent of arsenic content in the drinking water was 348.23 ± 102.67 μg/L, which was significantly lowered to 5.60 ± 10.83 μg/L in 2010-2011. Comparing the data obtained between 2004-2005 and 2010-2011, there was a significant decline in the MN frequency, when assayed in 2010-2011 compared to 2004-2005. Hence, we infer that urothelial MN can be utilized as a good biomarker in detecting remedial effects from toxicity of the low dose of arsenic through drinking water.

  1. Analysis of chromosomal radiosensitivity of healthy BRCA2 mutation carriers and non-carriers in BRCA families with the G2 micronucleus assay

    PubMed Central

    Baert, Annelot; Depuydt, Julie; Van Maerken, Tom; Poppe, Bruce; Malfait, Fransiska; Van Damme, Tim; De Nobele, Sylvia; Perletti, Gianpaolo; De Leeneer, Kim; Claes, Kathleen B.M.; Vral, Anne

    2017-01-01

    Breast cancer risk drastically increases in individuals with a heterozygous germline BRCA1 or BRCA2 mutation, while it is estimated to equal the population risk for relatives without the familial mutation (non-carriers). The aim of the present study was to use a G2 phase-specific micronucleus assay to investigate whether lymphocytes of healthy BRCA2 mutation carriers are characterized by increased radiosensitivity compared to controls without a family history of breast/ovarian cancer and how this relates to healthy non-carrier relatives. BRCA2 is active in homologous recombination, a DNA damage repair pathway, specifically active in the late S/G2 phase of the cell cycle. We found a significantly increased radiosensitivity in a cohort of healthy BRCA2 mutation carriers compared to individuals without a familial history of breast cancer (P=0.046; Mann-Whitney U test). At the individual level, 50% of healthy BRCA2 mutation carriers showed a radiosensitive phenotype (radiosensitivity score of 1 or 2), whereas 83% of the controls showed no radiosensitivity (P=0.038; one-tailed Fishers exact test). An odds ratio of 5 (95% CI, 1.07–23.47) indicated an association between the BRCA2 mutation and radiosensitivity in healthy mutation carriers. These results indicate the need for the gentle use of ionizing radiation for either diagnostic or therapeutic use in BRCA2 mutation carriers. We detected no increased radiosensitivity in the non-carrier relatives. PMID:28184943

  2. Genotoxic and Antigenotoxic Assessment of Chios Mastic Oil by the In Vitro Micronucleus Test on Human Lymphocytes and the In Vivo Wing Somatic Test on Drosophila.

    PubMed

    Vlastos, Dimitris; Drosopoulou, Elena; Efthimiou, Ioanna; Gavriilidis, Maximos; Panagaki, Dimitra; Mpatziou, Krystalenia; Kalamara, Paraskevi; Mademtzoglou, Despoina; Mavragani-Tsipidou, Penelope

    2015-01-01

    Chios mastic oil (CMO), the essential oil derived from Pistacia lentiscus (L.) var. chia (Duham), has generated considerable interest because of its antimicrobial, anticancer, antioxidant and other beneficial properties. In the present study, the potential genotoxic activity of CMO as well as its antigenotoxic properties against the mutagenic agent mitomycin-C (MMC) were evaluated by employing the in vitro Cytokinesis Block MicroNucleus (CBMN) assay and the in vivo Somatic Mutation And Recombination Test (SMART). In the in vitro experiments, lymphocytes were treated with 0.01, 0.05 and 0.10% (v/v) of CMO with or without 0.05 μg/ml MMC, while in the in vivo assay Drosophila larvae were fed with 0.05, 0.10, 0.50 and 1.00% (v/v) of CMO with or without 2.50 μg/ml MMC. CMO did not significantly increase the frequency of micronuclei (MN) or total wing spots, indicating lack of mutagenic or recombinogenic activity. However, the in vitro analysis suggested cytotoxic activity of CMO. The simultaneous administration of MMC with CMO did not alter considerably the frequencies of MMC-induced MN and wing spots showing that CMO doesn't exert antigenotoxic or antirecombinogenic action. Therefore, CMO could be considered as a safe product in terms of genotoxic potential. Even though it could not afford any protection against DNA damage, at least under our experimental conditions, its cytotoxic potential could be of interest.

  3. DNA damage induced by coal dust, fly and bottom ash from coal combustion evaluated using the micronucleus test and comet assay in vitro.

    PubMed

    Matzenbacher, Cristina Araujo; Garcia, Ana Letícia Hilario; Dos Santos, Marcela Silva; Nicolau, Caroline Cardoso; Premoli, Suziane; Corrêa, Dione Silva; de Souza, Claudia Telles; Niekraszewicz, Liana; Dias, Johnny Ferraz; Delgado, Tânia Valéria; Kalkreuth, Wolfgang; Grivicich, Ivana; da Silva, Juliana

    2017-02-15

    Coal mining and combustion generating huge amounts of bottom and fly ash are major causes of environmental pollution and health hazards due to the release of polycyclic aromatic hydrocarbons (PAH) and heavy metals. The Candiota coalfield in Rio Grande do Sul, is one of the largest open-cast coal mines in Brazil. The aim of this study was to evaluate genotoxic and mutagenic effects of coal, bottom ash and fly ash samples from Candiota with the comet assay (alkaline and modified version) and micronucleus test using the lung fibroblast cell line (V79). Qualitative and quantitative analysis of PAH and inorganic elements was carried out by High Performance Liquid Chromatography (HPLC) and by Particle-Induced X-ray Emission (PIXE) techniques respectively. The samples demonstrated genotoxic and mutagenic effects. The comet assay modified using DNA-glicosilase formamidopirimidina (FPG) endonuclease showed damage related to oxidative stress mechanisms. The amount of PAHs was higher in fly ash followed by pulverized coal. The amount of inorganic elements was highest in fly ash, followed by bottom ash. It is concluded that the samples induce DNA damage by mechanisms that include oxidative stress, due to their complex composition, and that protective measures have to be taken regarding occupational and environmental hazards.

  4. Comparison of 4', 6'-diamidino-2-phenylindole and Giemsa stainings in preimplantation mouse embryos micronucleus assay including a triple dose study.

    PubMed

    Tian, Ying; Shen, Li; Gao, Yu; Yamauchi, Toru; Shen, Xiao-ming; Ma, Ning

    2007-04-01

    Analysis of micronuclei (MN) in preimplantation embryos is a good method for the evaluation of cytogenetic damage induced by occupational and environmental mutagen during early pregnancy. To examine whether conventional Giemsa staining produced the same accuracy of micronuclei as the DNA-specific 4', 6'-diamidino-2-phenylindole (DAPI) staining in preimplantation embryo induced by maternal exposure to chlorpyrifos, we conducted assays on 469 mouse (3 groups) preimplantation embryos micronucleus. Slides were stained with DAPI. After DAPI staining, the slides were de-stained and restained with Giemsa. Giemsa staining showed similar frequencies in MN to DNA-specific DAPI staining in all three groups. Both staining techniques revealed significant increases in frequency of MN in the treated group in comparison to the control group. Both methods showed a statistically significant correlation between MN frequency and the dose of chlorpyrifos. Compared with DAPI staining, the sensitivity of Giemsa staining was 85.0%, 86.0% and 90.9% for control, 40 mg/kg, and 80 mg/kg chlorpyrifos treated group, respectively. The specificity was 97.9%, 91.4% and 96.5% for control, 40 mg/kg, and 80 mg/kg chlorpyrifos treated group, respectively. Thus, we recommend that Giemsa staining technique be a standard staining method in detecting MN of preimplantation embryos induced by occupational or environmental hazards.

  5. In vivo erythrocyte micronucleus assay III. Validation and regulatory acceptance of automated scoring and the use of rat peripheral blood reticulocytes, with discussion of non-hematopoietic target cells and a single dose-level limit test.

    PubMed

    Hayashi, Makoto; MacGregor, James T; Gatehouse, David G; Blakey, David H; Dertinger, Stephen D; Abramsson-Zetterberg, Lilianne; Krishna, Gopala; Morita, Takeshi; Russo, Antonella; Asano, Norihide; Suzuki, Hiroshi; Ohyama, Wakako; Gibson, Dave

    2007-02-03

    The in vivo micronucleus assay working group of the International Workshop on Genotoxicity Testing (IWGT) discussed new aspects in the in vivo micronucleus (MN) test, including the regulatory acceptance of data derived from automated scoring, especially with regard to the use of flow cytometry, the suitability of rat peripheral blood reticulocytes to serve as the principal cell population for analysis, the establishment of in vivo MN assays in tissues other than bone marrow and blood (for example liver, skin, colon, germ cells), and the biological relevance of the single-dose-level test. Our group members agreed that flow cytometric systems to detect induction of micronucleated immature erythrocytes have advantages based on the presented data, e.g., they give good reproducibility compared to manual scoring, are rapid, and require only small quantities of peripheral blood. Flow cytometric analysis of peripheral blood reticulocytes has the potential to allow monitoring of chromosome damage in rodents and also other species as part of routine toxicology studies. It appears that it will be applicable to humans as well, although in this case the possible confounding effects of splenic activity will need to be considered closely. Also, the consensus of the group was that any system that meets the validation criteria recommended by the IWGT (2000) should be acceptable. A number of different flow cytometric-based micronucleus assays have been developed, but at the present time the validation data are most extensive for the flow cytometric method using anti-CD71 fluorescent staining especially in terms of inter-laboratory collaborative data. Whichever method is chosen, it is desirable that each laboratory should determine the minimum sample size required to ensure that scoring error is maintained below the level of animal-to-animal variation. In the second IWGT, the potential to use rat peripheral blood reticulocytes as target cells for the micronucleus assay was discussed

  6. Evaluation of the sensitivity and specificity of in vivo erythrocyte micronucleus and transgenic rodent gene mutation tests to detect rodent carcinogens.

    PubMed

    Morita, Takeshi; Hamada, Shuichi; Masumura, Kenichi; Wakata, Akihiro; Maniwa, Jiro; Takasawa, Hironao; Yasunaga, Katsuaki; Hashizume, Tsuneo; Honma, Masamitsu

    2016-05-01

    Sensitivity and/or specificity of the in vivo erythrocyte micronucleus (MN) and transgenic rodent mutation (TGR) tests to detect rodent carcinogens and non-carcinogens were investigated. The Carcinogenicity and Genotoxicity eXperience (CGX) dataset created by Kirkland et al. was used for the carcinogenicity and in vitro genotoxicity data, i.e., Ames and chromosome aberration (CA) tests. Broad literature surveys were conducted to gather in vivo MN or TGR test data to add to the CGX dataset. Genotoxicity data in vitro were also updated slightly. Data on 379 chemicals (293 carcinogens and 86 non-carcinogens) were available for the in vivo MN test; sensitivity, specificity or concordances were calculated as 41.0%, 60.5% or 45.4%, respectively. For the TGR test, data on 80 chemicals (76 carcinogens and 4 non-carcinogens) were available; sensitivity was calculated as 72.4%. Based on the recent guidance on genotoxicity testing strategies, performance (sensitivity/specificity) of the following combinations was calculated; Ames+in vivo MN (68.7%/45.3%), Ames+TGR (83.8%/not calculated (nc)), Ames+in vitro CA+in vivo MN (80.8%/21.3%), Ames+in vitro CA+TGR (89.1%/nc), Ames+in vivo MN+TGR (87.5%/nc), Ames+in vitro CA+in vivo MN+TGR (89.3%/nc). Relatively good balance in performance was shown by the Ames+in vivo MN in comparison with Ames+in vitro CA (74.3%/37.5%). Ames+TGR and Ames+in vivo MN+TGR gave even higher sensitivity, but the specificity could not be calculated (too few TGR data on non-carcinogens). This indicates that in vivo MN and TGR tests are both useful as in vivo tests to detect rodent carcinogens.

  7. Micronucleus assay with urine derived cells (UDC): a review of its application in human studies investigating genotoxin exposure and bladder cancer risk.

    PubMed

    Nersesyan, Armen; Kundi, Michael; Fenech, Michael; Bolognesi, Claudia; Misik, Miroslav; Wultsch, Georg; Hartmann, Michaele; Knasmueller, Siegfried

    2014-01-01

    The first micronucleus (MN) study with urine derived cells (UDC) appeared 30 years ago. So far, 56 investigations have been published with this method and it was shown that it can be used for the detection of chromosomal damage caused by environmental and lifestyle factors as well as by occupational exposures and certain diseases This approach may be also useful as a diagnostic tool for the detection and prognosis of bladder cancer. The test system has been improved in the last years, i.e., it was shown that, apart from MN also other nuclear anomalies can be evaluated in UDC which are found in other types of epithelial cells as well (e.g., in oral and nasal cells) and are indicative for acute toxicity (pyknosis, karyorrhexis, karyolysis, condensed chromatin) and genomic instability (nuclear buds, binucleates). Furthermore, an improved protocol with Carnoy I fixation and Papanicolaou stain was developed which enables the discrimination between cells which originate from the cervix and those from the urothelium. The evaluation of the currently available results indicates that exposures and health conditions which are associated with increased cancer rates in the bladder (and possibly also in other organs) lead to positive results in MN-UDC assays and a limited number of studies indicate that this method may be equally sensitive as other more frequently used human biomonitoring assays. The major shortcoming of the UDC-MN method is the lack of standardization; the evaluation of the current data shows that a variety of staining and fixation methods are used and that the numbers of evaluated cells vary over a broad range. These inconsistencies may account for the large inter-laboratory variations of the background frequencies. In order to improve the reliability of the method, further standardization and validation is required. Therefore an international program should be initiated in which a similar strategy could be used as in previous validation

  8. Correlation of In  Vivo Versus In Vitro Benchmark Doses (BMDs) Derived From Micronucleus Test Data: A Proof of Concept Study

    PubMed Central

    Soeteman-Hernández, Lya G.; Fellows, Mick D.; Johnson, George E.; Slob, Wout

    2015-01-01

    In this study, we explored the applicability of using in vitro micronucleus (MN) data from human lymphoblastoid TK6 cells to derive in vivo genotoxicity potency information. Nineteen chemicals covering a broad spectrum of genotoxic modes of action were tested in an in vitro MN test using TK6 cells using the same study protocol. Several of these chemicals were considered to need metabolic activation, and these were administered in the presence of S9. The Benchmark dose (BMD) approach was applied using the dose-response modeling program PROAST to estimate the genotoxic potency from the in vitro data. The resulting in vitro BMDs were compared with previously derived BMDs from in vivo MN and carcinogenicity studies. A proportional correlation was observed between the BMDs from the in vitro MN and the BMDs from the in vivo MN assays. Further, a clear correlation was found between the BMDs from in vitro MN and the associated BMDs for malignant tumors. Although these results are based on only 19 compounds, they show that genotoxicity potencies estimated from in vitro tests may result in useful information regarding in vivo genotoxic potency, as well as expected cancer potency. Extension of the number of compounds and further investigation of metabolic activation (S9) and of other toxicokinetic factors would be needed to validate our initial conclusions. However, this initial work suggests that this approach could be used for in vitro to in vivo extrapolations which would support the reduction of animals used in research (3Rs: replacement, reduction, and refinement). PMID:26443842

  9. [Selective accumulation of 147Pm in organism on induction of micronucleus and SCE of bone marrow cells as well as the mutagenic effect on fetal liver and spleen].

    PubMed

    Zhu, S P

    1989-05-01

    Study of accumulation peculiarity of 147Pm showed that iv. different doses of 147Pm were the same selectively localized in skeleton. Retention of 147Pm in skeleton was elevated when the radioactive doses of 147Pm were increased. At the same time absorption dose of 147Pm radiation was also raised. The ability of 147Pm to induce sister chromatid exchanges (SCEs) has been investigated by IdU labelling methods. A statistically significant elevation of SCEs was observed after 147Pm intake. The number of SCEs per cell in bone marrow cells was always higher in mice when the animals were maintained on the doses of 37 Bq/g. We observed the injurious effects of 147Pm, using micronucleus rates in bone marrow cells as indicator. The results showed that the lower limit of injected activity effecting marked rise of rates was 185 Bq/g A peak rate of 1.34% was reached at 24 here after intake of 147Pm 1.85 x 10(5) Bq/g. Our study is also to ascertain the correlation between maternal deposition, perinatal uptake of 147Pm and their chromosome aberrations of maternal and fetal liver cells. Results indicated that 147Pm was predominantly deposited in maternal liver. Deposition of 147Pm in maternal spleen was about one quarter of that in the maternal liver. In view of the placental barrier uptake of 147Pm by fetal liver or spleen was definitely depressed. Studies indicated that maternal contamination of 147Pm could induce chromosome aberrations in fetal liver and spleen cells. Among the type of aberrations induced by 147Pm, chromatid breakage were predominant.(ABSTRACT TRUNCATED AT 250 WORDS)

  10. Assessment of DNA damage in coal open-cast mining workers using the cytokinesis-blocked micronucleus test and the comet assay.

    PubMed

    León-Mejía, Grethel; Espitia-Pérez, Lyda; Hoyos-Giraldo, Luz Stella; Da Silva, Juliana; Hartmann, Andreas; Henriques, João Antônio Pêgas; Quintana, Milton

    2011-01-15

    Coal mining is one of the most important causes of environmental pollution, as large quantities of coal dust particles are emitted. Colombia-South America has large natural coal reserves and "El Cerrejón" is the world's largest open-cast mine located in the northern department of Guajira. The aim of the present study was to evaluate genotoxic effects in a population exposed to coal residues from the open-cast mine "El Cerrejón". 100 exposed workers and 100 non-exposed control individuals were included in this study. The exposed group was divided according to different mining area activities: (i). Transport of extracted coal, (ii). Equipment field maintenance, (iii). Coal stripping and, (iv). Coal embarking. Blood samples were taken to investigate biomarkers of genotoxicity, specifically, primary DNA damage as damage index (DI), tail length and% of tail DNA using the Comet assay (alkaline version) and chromosome damage as micronucleus (MN) frequency in lymphocytes. Both biomarkers showed statistically significantly higher values in the exposed group compared to the non-exposed control group. No difference was observed between the exposed groups executing different mining activities. These results indicate that exposure to coal mining residues may result in an increased genotoxic exposure in coal mining workers. We did not find a correlation between age, alcohol consumption and service time with the biomarkers of genotoxicity. Our results are the first data of genotoxic effects induced by coal mining exposure in Colombia, and thus, contribute to the exploration of test batteries use for monitoring of exposed populations and may stimulate designing control, hygiene and prevention strategies for occupational health risk assessment in developing countries.

  11. Application of the DNA adductome approach to assess the DNA-damaging capability of in vitro micronucleus test-positive compounds.

    PubMed

    Kato, Kyoko; Yamamura, Eiji; Kawanishi, Masanobu; Yagi, Takashi; Matsuda, Tomonari; Sugiyama, Akio; Uno, Yoshifumi

    2011-03-18

    The in vitro micronucleus (MN) test is widely used for screening genotoxic compounds, but it often produces false-positive results. To consider the significance of positive results, it is important to know whether DNA adducts are formed in the cells treated with the test compound. Recently, Matsuda et al. developed the DNA adductome approach to detect DNA adducts comprehensively ([4] Kanaly, et al., Antioxid. Redox Signal., 2006, 8, 993-1001). We applied this method to assess the DNA-damaging capability of in vitro MN test-positive compounds. CHL/IU cells were treated with compounds from three categories: (1) carcinogens causing DNA alkylation, ethyl methanesulfonate and N-methyl-N'-nitro-N-nitrosoguanidine; (2) carcinogens producing DNA bulky adducts, 2-amino-6-phenyl-1-methylimidazo[4,5-b]pyrene, benzo[a]pyrene, 7,12-dimethylbenz[a]anthracene, and 4-nitroquinoline-1-oxide, and (3) non-carcinogens, caffeine, maltol, and sodium chloride, with or without metabolic activation. With the conditions in which all test compounds gave positive results in the MN tests, DNA was extracted from the cells and hydrolyzed to deoxyribonucleosides, which were subsequently subjected to LC/ESI-MS/MS analysis. All carcinogens (categories 1 and 2) produced various DNA adduct peaks, and some of the m/z peak values corresponded to known adducts. No non-carcinogens produced DNA adducts, indicating that these compounds produced MN through different mechanisms from the adduct formation. These results indicate that the adductome approach is useful to demonstrate DNA damage formation of MN test-positive compounds and to understand their mechanisms of action.

  12. Poor recognition of O6-isopropyl dG by MGMT triggers double strand break-mediated cell death and micronucleus induction in FANC-deficient cells

    PubMed Central

    Hashimoto, Kiyohiro; Sharma, Vyom; Sasanuma, Hiroyuki; Tian, Xu; Takata, Minoru; Takeda, Shunichi; Swenberg, James A.; Nakamura, Jun

    2016-01-01

    Isopropyl methanesulfonate (IPMS) is the most potent genotoxic compound among methanesulfonic acid esters. The genotoxic potential of alkyl sulfonate esters is believed to be due to their alkylating ability of the O6 position of guanine. Understanding the primary repair pathway activated in response to IPMS-induced DNA damage is important to profile the genotoxic potential of IPMS. In the present study, both chicken DT40 and human TK6 cell-based DNA damage response (DDR) assays revealed that dysfunction of the FANC pathway resulted in higher sensitivity to IPMS compared to EMS or MMS. O6-alkyl dG is primarily repaired by methyl guanine methyltransferase (MGMT), while isopropyl dG is less likely to be a substrate for MGMT. Comparison of the cytotoxic potential of IPMS and its isomer n-propyl methanesulfonate (nPMS) revealed that the isopropyl moiety avoids recognition by MGMT and leads to higher cytotoxicity. Next, the micronucleus (MN) assay showed that FANC deficiency increases the sensitivity of DT40 cells to MN induction by IPMS. Pretreatment with O6-benzyl guanine (OBG), an inhibitor of MGMT, increased the MN frequency in DT40 cells treated with nPMS, but not IPMS. Lastly, IPMS induced more double strand breaks in FANC-deficient cells compared to wild-type cells in a time-dependent manner. All together, these results suggest that IPMS-derived O6-isopropyl dG escapes recognition by MGMT, and the unrepaired DNA damage leads to double strand breaks, resulting in MN induction. FANC, therefore, plays a pivotal role in preventing MN induction and cell death caused by IPMS. PMID:27486975

  13. Associations between DNA methylation in DNA damage response-related genes and cytokinesis-block micronucleus cytome index in diesel engine exhaust-exposed workers.

    PubMed

    Zhang, Xiao; Li, Jie; He, Zhini; Duan, Huawei; Gao, Weimin; Wang, Haisheng; Yu, Shanfa; Chen, Wen; Zheng, Yuxin

    2016-08-01

    Recently, diesel engine exhaust (DEE) was reclassified as a known carcinogen to humans. DNA methylation alterations in DNA damage response (DDR)-related genes have the potential to affect DEE exposure-related cancer risk. However, the evidence regarding the association between DEE exposure and methylation alterations in DDR-related genes is limited. In 117 DEE-exposed workers and 112 non-DEE-exposed workers, we measured urinary concentrations of six mono-hydroxylated polycyclic aromatic hydrocarbons (OH-PAHs). We also determined the methylation levels of three DDR-related genes (p16, RASSF1A, and MGMT) and LINE-1 by bisulfite-pyrosequencing assay. We found that DEE-exposed workers exhibited significantly lower mean promoter methylation levels of p16, RASSF1A, and MGMT than non-DEE-exposed workers (all p < 0.001). In all study subjects and non-smoking workers, increasing quartiles of urinary summed OH-PAHs was associated with hypomethylation of p16, RASSF1A, and MGMT (all p < 0.05). In non-smoking workers, methylation in p16, RASSF1A, and MGMT decreased by 0.36 % [95 % confidential interval (CI): -0.60, -0.11 %], 0.46 % (95 % CI: -0.79, -0.14 %), and 0.55 % (95 % CI: -0.95, -0.15 %), respectively, in association with highest versus lowest quartile of urinary summed OH-PAHs. In addition, p16, RASSF1A, MGMT, and LINE-1 methylation levels showed negative correlations with cytokinesis-block micronucleus cytome index which was previously measured in the same workers (all p < 0.05). In conclusion, our results clearly indicated that DEE exposure and increased genetic damage were associated with hypomethylation of p16, RASSF1A, and MGMT. Future studies with larger sample size are needed to confirm these associations.

  14. SiO2 Nanoparticule-induced size-dependent genotoxicity - an in vitro study using sister chromatid exchange, micronucleus and comet assay.

    PubMed

    Battal, Dilek; Çelik, Ayla; Güler, Gizem; Aktaş, Ayça; Yildirimcan, Saadet; Ocakoglu, Kasim; Çömelekoǧlu, Ülkü

    2015-04-01

    Fine particles with a characteristic size smaller than 100 nm (i.e. nanoparticlesspread out in nowadays life. Silicon or Si, is one of the most abundant chemical elements found on the Earth. Its oxide forms, such as silicate (SiO4) and silicon dioxide, also known as silica (SiO2), are the main constituents of sand and quartz contributing to 90% of the Earth's crust. In this work, three genotoxicity systems "sister chromatid exchange, cytokinesis block micronucleus test and single cell gel electrophoresis (comet) assay" were employed to provide further insight into the cytotoxic and mutagenic/genotoxic potential of SiO2 nanoparticules (particle size 6 nm, 20 nm, 50 nm) in cultured peripheral blood lymphocytes as in vitro. It was observed that there is a significant decrease in Mitotic index (MI), Cytokinesis block proliferation index (CBPI), proliferation index (PRI) values expressed as Cell Kinetic parameters compared with negative control (p < 0.05). There is a statistically significant difference between negative control culture and culture exposed to SiO2 (6 nm, 20 nm, 50 nm) (p < 0.01, p < 0.01, p < 0.05, respectively). It is found that SiO2 nanoparticles at different size (6, 20, 50 nm) progressively increased the SCE frequency and DNA damage on the basis the AU values compared with negative control (p < 0.05). Results showed that the genotoxic/mutagenic and cytotoxic effects of SiO2 nanoparticules is dependent to particule size.

  15. Use of the fluorescent micronucleus assay to detect the genotoxic effects of radiation and arsenic exposure in exfoliated human epithelial cells

    SciTech Connect

    Moore, L.E.; Warner, M.L.; Smith, A.H.

    1996-12-31

    The exfoliated cell micronucleus (MN) assay using fluorescent in situ hybridization (FISH) with a centromeric probe is a rapid method for determining the mechanism of MN formation in epithelial tissues exposed to carcinogenic agents. Here, we describe the use of this assay to detect the presence or absence of centromeric DNA in MN induced in vivo by radiation therapy and chronic arsenic (As) ingestion. We examined the buccal cells of an individual receiving 6,500 rads of photon radiation to the head and neck. Exfoliated cells were collected before, during, and after treatment. After radiation exposure a 16.6-fold increase in buccal cell MN frequency was seen. All induced MN were centromere negative (MN-) resulting from chromosome breakage. This finding is consistent with the clastogenic action of radiation and confirmed the reliability of the method. Three weeks post-therapy, MN frequencies returned to baseline. The assay was used on 18 people chronically exposed to high levels of inorganic arsenic (In-As) in drinking water (average level, 1,312 {mu}g As/L) and 18 matched controls (average level, 16 {mu}g As/L). The combined increase in MN frequency was 1.8-fold (P = 0.001, Fisher`s exact test). Frequencies of micronuclei containing acentric fragments (MN-) and those containing whole chromosomes (MN+) both increased, suggesting that arsenic may have both clastogenic and weak aneuploidogenic properties in vivo. After stratification on sex, the effect was stronger in male than in female bladder cells. In males the MN-frequency increased 2.06-fold (P =0.07) while the frequency of MN+ increased 1.86-fold (P = 0.08). In addition, the frequencies of MN and MN+ were positively associated with urinary arsenic and its metabolites. The association was stronger for micronuclei containing acentric fragments. By using FISH with centromeric probes, the mechanism of chemically induced genotoxicity can not be determined in epithelial tissues. 35 refs., 4 tabs.

  16. Duodenal crypt health following exposure to Cr(VI): Micronucleus scoring, γ-H2AX immunostaining, and synchrotron X-ray fluorescence microscopy

    SciTech Connect

    Thompson, Chad M.; Wolf, Jeffrey C.; Elbekai, Reem H.; Paranjpe, Madhav G.; Seiter, Jennifer M.; Chappell, Mark A.; Tappero, Ryan V.; Suh, Mina; Proctor, Deborah M.; Bichteler, Anne; Haws, Laurie C.; Harris, Mark A.

    2015-08-01

    Lifetime exposure to high concentrations of hexavalent chromium [Cr(VI)] in drinking water results in intestinal damage and an increase in duodenal tumors in B6C3F1 mice. To assess whether these tumors could be the result of a direct mutagenic or genotoxic mode of action, we conducted a GLP-compliant 7-day drinking water study to assess crypt health along the entire length of the duodenum. Mice were exposed to water (vehicle control), 1.4, 21, or 180 ppm Cr(VI) via drinking water for 7 consecutive days. Crypt enterocytes in Swiss roll sections were scored as normal, mitotic, apoptotic, karyorrhectic, or as having micronuclei. A single oral gavage of 50 mg/kg cyclophosphamide served as a positive control for micronucleus induction. Exposure to 21 and 180 ppm Cr(VI) significantly increased the number of crypt enterocytes. Micronuclei and γ-H2AX immunostaining were not elevated in the crypts of Cr(VI)-treated mice. In contrast, treatment with cyclophosphamide significantly increased numbers of crypt micronuclei and qualitatively increased γ-H2AX immunostaining. Synchrotron-based X-ray fluorescence (XRF) microscopy revealed the presence of strong Cr fluorescence in duodenal villi, but negligible Cr fluorescence in the crypt compartment. Together, these data indicate that Cr(VI) does not adversely effect the crypt compartment where intestinal stem cells reside, and provide additional evidence that the mode of action for Cr(VI)-induced intestinal cancer in B6C3F1 mice involves chronic villous wounding resulting in compensatory crypt enterocyte hyperplasia.

  17. Inter-individual variability in the response of human peripheral blood lymphocytes to ionizing radiation: comparison of the dicentric and micronucleus assays.

    PubMed

    Pajic, Jelena; Rakic, Boban; Rovcanin, Branislav; Jovicic, Dubravka; Novakovic, Ivana; Milovanovic, Aleksandar; Pajic, Vesna

    2015-08-01

    Ionizing radiation can induce a wide range of DNA damage that leads to chromosomal aberrations. Some of those aberrations (dicentrics and micronuclei) are applied in biodosimetry. Biological dosimetry assumes similar radiosensitivity of each donor, but it does not exclude inter-individual variations in radiation susceptibility. Therefore, for biological reasons, it is always challenging to investigate inter-individual variability in response to radiation. For mechanistic reasons, it is also interesting to investigate the correlation between dicentric and micronuclei formation in response to radiation. In this experiment, irradiated blood specimens from 14 healthy male and female donors have been used to evaluate inter-individual variability in response to the genotoxic effects of X-ray radiation, as well as the dose-response relationship and test sensitivity using two endpoints (dicentrics and micronuclei). The results showed similar patterns of cytogenetic biomarker distribution between donors, but differences in the response of some donors at some doses. Data also showed that responses of male donors were better detected using the dicentric test, while for females, micronucleus frequencies were higher in response to the same dose of radiation. No influence of smoking status or age on specific responses was observed. Group variability in response to radiation was evaluated using coefficient of variation for each group of individuals irradiated with the same doses; as the dose increases, group variability becomes substantially lower. Despite sporadic inter-individual variability, trend of radiation-induced changes was similar. Produced calibration curves for both types of damage revealed dicentrics as genetic damage more typical for radiation than micronuclei.

  18. Increased incidence of micronuclei assessed with the micronucleus assay and the fluorescence in situ hybridization (FISH) technique in peripheral blood lymphocytes of nurses exposed to nitrous oxide.

    PubMed

    Lewińska, D; Stepnik, M; Krajewski, W; Arkusz, J; Stańczyk, M; Wrońska-Nofer, T

    2005-03-07

    It has been postulated that exposure to nitrous oxide and halogenated anaesthetics is associated with various adverse health effects such as neurological and reproductive abnormalities or impairment of hepatic functions. In spite of the quite well known genotoxic effects of exposure to nitrous oxide in vivo, the mechanisms of these effects are still not clear. The aim of this study was to assess the frequency of micronuclei and to identify the type of chromosomal damage (clastogenic or aneugenic) in peripheral blood lymphocytes of operating-room nurses exposed to nitrous oxide. The study group comprised 46 women working at departments where the concentration of nitrous oxide ranged from 14 to 2308 mg/m3. The control population was composed of 28 women employed in the same hospitals but in non-surgical departments. The clastogenic/aneugenic effect of nitrous oxide was evaluated in lymphocytes using the standard micronucleus (MN) assay in combination with the fluorescence in situ hybridization (FISH) technique with pancentromeric probes. The results show a significant increase of the MN frequency in lymphocytes of exposed nurses compared with the control group (4.36+/-2.23 versus 9.02+/-4.67). The multiple regression analysis revealed a statistically significant relationship (p=0.0009) between MN frequency and exposure status, indicating that the level of exposure was the main factor affecting chromosomal damage. As assessed by FISH analysis, the overall frequencies of centromere-positive MN in the control and exposed groups were 43 and 49%, respectively. The increase observed in the exposed group may suggest a slight, statistically insignificant pro-aneugenic effect of exposure to nitrous oxide.

  19. Biomonitoring of humans exposed to arsenic, chromium, nickel, vanadium, and complex mixtures of metals by using the micronucleus test in lymphocytes.

    PubMed

    Annangi, Balasubramanyam; Bonassi, Stefano; Marcos, Ricard; Hernández, Alba

    Various metals have demonstrated genotoxic and carcinogenic potential via different mechanisms. Until now, biomonitoring and epidemiological studies have been carried out to assess the genotoxic risk to exposed human populations. In this sense, the use of the micronucleus assay in peripheral blood lymphocytes has proven to be a useful tool to determine increased levels of DNA damage, as a surrogate biomarker of cancer risk. Here we review those biomonitoring studies focused on people exposed to arsenic, chromium, nickel, vanadium and complex mixtures of metals. Only those studies that used the frequency of micronuclei in binucleated (BNMN) cells have been taken into consideration, although the inclusion of other biomarkers of exposure and genotoxicity are also reflected and discussed. Regarding arsenic, most of the occupational and environmental biomonitoring studies find an increase in BNMN among the exposed individuals. Thus, it seems conclusive that arsenic exposure increases the risk of exposed human populations. However, a lack of correlation between the level of exposure and the increase in BNMN is also common, and a limited number of studies evaluated the genotype as a risk modulator. As for chromium, a BNMN increase in occupationally exposed subjects and a correlation between level of exposure and effect is found consistently in the available literature. However, the quality score of the studies is only medium-low. On the other hand, the studies evaluating nickel and vanadium are scarce and lacks a correct characterization of the individual exposure, which difficult the building of clear conclusions. Finally, several studies with medium-high quality scores evaluated a more realistic scenario of exposure which takes into account a mixture of metals. Among them, those which correctly characterized and measured the exposure were able to find association with the level of BNMN. Also, several genes associated with DNA damage repair such as OGG1 and XRCC1 were

  20. Genotoxicity of doxorubicin in F344 rats by combining the comet assay, flow-cytometric peripheral blood micronucleus test, and pathway-focused gene expression profiling.

    PubMed

    Manjanatha, Mugimane G; Bishop, Michelle E; Pearce, Mason G; Kulkarni, Rohan; Lyn-Cook, Lascelles E; Ding, Wei

    2014-01-01

    Doxorubicin (DOX) is an antineoplastic drug effective against many human malignancies. DOX's clinical efficacy is greatly limited because of severe cardiotoxicity. To evaluate if DOX is genotoxic in the heart, ~7-week-old, male F344 rats were administered intravenously 1, 2, and 3 mg/kg bw DOX at 0, 24, 48, and 69 hr and the Comet assays in heart, liver, kidney, and testis and micronucleus (MN) assay in the peripheral blood (PB) erythrocytes using flow cytometry were conducted. Rats were euthanized at 72 hr and PB was removed for the MN assay and single cells were isolated from multiple tissues for the Comet assays. None of the doses of DOX induced a significant DNA damage in any of the tissues examined by the alkaline Comet assay. Contrastingly, the glycosylase enzymes-modified Comet assay showed a significant dose dependent increase in the oxidative DNA damage in the cardiac tissue (P ≤ 0.05). In the liver, only the top dose induced significant increase in the oxidative DNA damage (P ≤ 0.05). The histopathology showed no severe cardiotoxicity but non-neoplastic lesions were present in both untreated and treated samples. A severe toxicity likely occurred in the bone marrow because no viable reticulocytes could be screened for the MN assay. Gene expression profiling of the heart tissues showed a significant alteration in the expression of 11 DNA damage and repair genes. These results suggest that DOX is genotoxic in the heart and the DNA damage may be induced primarily via the production of reactive oxygen species.

  1. Nicotine derived genotoxic effects in human primary parotid gland cells as assessed in vitro by comet assay, cytokinesis-block micronucleus test and chromosome aberrations test.

    PubMed

    Ginzkey, Christian; Steussloff, Gudrun; Koehler, Christian; Burghartz, Marc; Scherzed, Agmal; Hackenberg, Stephan; Hagen, Rudolf; Kleinsasser, Norbert H

    2014-08-01

    Genotoxic effects of nicotine were described in different human cells including salivary gland cells. Based on the high nicotine concentration in saliva of smokers or patients using therapeutic nicotine patches, the current study was performed to evaluate the genotoxic potential of nicotine in human salivary gland cells. Therefore, primary salivary gland cells from 10 patients undergoing parotid gland surgery were exposed to nicotine concentrations between 1 μM and 1000 μM for 1 h in the absence of exogenous metabolic activation. The acinar phenotype was proven by immunofluorescent staining of alpha-amylase. Genotoxic effects were evaluated using the Comet assay, the micronucleus test and the chromosome aberration test. Cytotoxicity and apoptosis were determined by trypan blue exclusion test and Caspase-3 assay. Nicotine was able to induce genotoxic effects in all three assays. The chromosome aberration test was the most sensitive and increases in numerical and structural (chromatid-type and chromosome-type) aberrations were seen at ≥1 μM, whereas increases in micronuclei frequency were detected at 10 μM and DNA damage as measured in the Comet assay was noted at >100 μM. No cytotoxic damage or influence of apoptosis could be demonstrated. Nicotine as a possible risk factor for tumor initiation in salivary glands is still discussed controversially. Our results demonstrated the potential of nicotine to induce genotoxic effects in salivary gland cells. These results were observed at saliva nicotine levels similar to those found after oral or transdermal exposure to nicotine and suggest the necessity of careful monitoring of the use of nicotine in humans.

  2. Application of the SOS/umu test and high-content in vitro micronucleus test to determine genotoxicity and cytotoxicity of nine benzothiazoles.

    PubMed

    Ye, Yan; Weiwei, Jiang; Na, Li; Mei, Ma; Kaifeng, Rao; Zijian, Wang

    2014-12-01

    Benzothiazole and benzothiazole derivatives (BTs) have been detected in various environmental matrices as well as in human beings, but little is currently available regarding their toxicities. In our study, genotoxicities of nine BTs (benzothiazole [BT], 2-chlorobenzothiazole [CBT], 2-bromobenzothiazole [BrBT], 2-fluorobenzothiazole [FBT], 2-methylbenzothiazole [MeBT], 2-mercaptobenzothiazole [MBT], 2-aminobenzothiazole [ABT], 2-hydroxy-benzothiazole [OHBT] and 2-methythiobenzothiazole [MTBT]) are comprehensively evaluated by the SOS/umu test using the bacterial Salmonella typhimurium TA1535/pSK1002 for DNA-damaging effect and the high content in vitro micronucleus test using two human carcinoma cells (MGC-803 and A549) for chromosome-damaging effect. The cytotoxicity of BTs on both bacteria and two human cells was also evaluated. Except for the cytotoxic effect of MBT on MGC-803 and A549, the other tested BTs showed more than 50% cytotoxicity at their highest concentrations in a dose-dependent manner, and their LC50s ranged from 19 (MBT in bacteria) to 270 mg l(-1) (CBT in A549). Activation and inactivation were observed for specific BTs after metabolism. On the other hand, no evidence of genotoxicity was obtained for BT, FBT and MBT, and DNA damage was induced by ABT, OHBT, BrBT and MTBT in MGC-803, by MeBT in A549 and by CBT in both cells. Through quantitative structure-activity relationship analysis, two structure alerts for chemical genotoxicity, including heterocyclic amine and hacceptor-path3-hacceptor are present in ABT and OHBT respectively; however, the underlying mechanisms still need further evaluation.

  3. Evaluation of titanium dioxide nanocrystal-induced genotoxicity by the cytokinesis-block micronucleus assay and the Drosophila wing spot test.

    PubMed

    Reis, Érica de Melo; Rezende, Alexandre Azenha Alves de; Oliveira, Pollyanna Francielli de; Nicolella, Heloiza Diniz; Tavares, Denise Crispim; Silva, Anielle Christine Almeida; Dantas, Noelio Oliveira; Spanó, Mário Antônio

    2016-10-01

    Titanium dioxide nanocrystals (TiO2 NCs) crystalline structures include anatase, rutile and brookite. This study evaluated the genotoxic effects of 3.4 and 6.2 nm anatase TiO2 NCs and 78.0 nm predominantly rutile TiO2 NCs through an in vitro micronucleus (MN) assay using V79 cells and an in vivo somatic mutation and recombination test in Drosophila wings. The MN assay was performed with nontoxic concentrations of TiO2 NCs. Only anatase (3.4 nm) at the highest concentration (120 μM) induced genotoxicity in V79 cells. In the in vivo test, Drosophila melanogaster larvae obtained from standard (ST) or high bioactivation (HB) crosses were treated with TiO2 NCs. In the ST cross, no mutagenic effects were observed. However, in the HB cross, TiO2 NCs (3.4 nm) were mutagenic at 1.5625 and 3.125 mM, while 78.0 nm NCs increased mutant spots at all concentrations tested except 3.125 mM. Only the smallest anatase TiO2 NCs induced mutagenic effects in vitro and in vivo. For rutile TiO2 NCs, no clastogenic/aneugenic effects were observed in the MN assay. However, they were mutagenic in Drosophila. Therefore, both anatase and rutile TiO2 NCs induced mutagenicity. Further research is necessary to clarify the TiO2 NCs genotoxic/mutagenic action mechanisms.

  4. Automation of the in vitro micronucleus and chromosome aberration assay for the assessment of the genotoxicity of the particulate and gas-vapor phase of cigarette smoke.

    PubMed

    Roemer, Ewald; Zenzen, Volker; Conroy, Lynda L; Luedemann, Kathrin; Dempsey, Ruth; Schunck, Christian; Sticken, Edgar Trelles

    2015-01-01

    Total particulate matter (TPM) and the gas-vapor phase (GVP) of mainstream smoke from the Reference Cigarette 3R4F were assayed in the cytokinesis-block in vitro micronucleus (MN) assay and the in vitro chromosome aberration (CA) assay, both using V79-4 Chinese hamster lung fibroblasts exposed for up to 24 h. The Metafer image analysis platform was adapted resulting in a fully automated evaluation system of the MN assay for the detection, identification and reporting of cells with micronuclei together with the determination of the cytokinesis-block proliferation index (CBPI) to quantify the treatment-related cytotoxicity. In the CA assay, the same platform was used to identify, map and retrieve metaphases for a subsequent CA evaluation by a trained evaluator. In both the assays, TPM and GVP provoked a significant genotoxic effect: up to 6-fold more micronucleated target cells than in the negative control and up to 10-fold increases in aberrant metaphases. Data variability was lower in the automated version of the MN assay than in the non-automated. It can be estimated that two test substances that differ in their genotoxicity by approximately 30% can statistically be distinguished in the automated MN and CA assays. Time savings, based on man hours, due to the automation were approximately 70% in the MN and 25% in the CA assays. The turn-around time of the evaluation phase could be shortened by 35 and 50%, respectively. Although only cigarette smoke-derived test material has been applied, the technical improvements should be of value for other test substances.

  5. Sublethal toxicity of esbiothrin relationship with total antioxidant status and in vivo genotoxicity assessment in fish (Cyprinus carpio L., 1758) using the micronucleus test and comet assay.

    PubMed

    Selvi, Mahmut; Cavaş, Tolga; Cağlan Karasu Benli, A; Koçak Memmi, Burcu; Cinkılıç, Nilüfer; Dinçel, Aylin Sepici; Vatan, Ozgür; Yılmaz, Dilek; Sarıkaya, Rabia; Zorlu, Tolga; Erkoç, Figen

    2013-11-01

    Esbiothrin, synthetic pyrethroid with quick activity against insects, is widely used against household pests and in public health. Despite widespread use, data on ecotoxicity and genotoxic effects are extremely scarce. The aim of the present study is to evaluate the genotoxic potential of esbiothrin on a model fish species Cyprinus carpio L., 1758 (Pisces: Cyprinidae, koi) using the micronucleus test and comet assay in peripheral blood erythrocytes. Effects of two sublethal exposure concentrations on plasma total antioxidant status (TAS mmol/L), and Hct values were examined. On the basis of the 96 h LC50 data from U.S. EPA ecotox database (32 μg/L) two sublethal exposure concentrations (5 and 10 μg/L) were used together with ethyl methanesulfonate (EMS) (5 mg/L) as positive control. Five fish were used for each dose/duration group (24, 48, and 72 h) under controlled laboratory conditions. The fish showed behavioral changes at the higher dose. Plasma TAS (mmol/L) levels decreased in 24 h; an increase was observed slightly for 48 and obviously for 72 h in both exposure doses. Similarly, hematocrit (Hct) values differed between exposure duration but no significant differences in mean values were found between groups of the same exposure time. The general trend was a rise after 48 h, which decreased afterwards. Our results revealed significant increases in the frequencies of micronuclei and levels of DNA strand breaks and thus demonstrated the genotoxic potential of this pesticide on fish, a nontarget organism of the aquatic ecosystem. To our knowledge this is the first study to report observable genotoxic effects of esbiothrin on fish.

  6. In vitro genotoxicity of neutral red after photo-activation and metabolic activation in the Ames test, the micronucleus test and the comet assay.

    PubMed

    Guérard, Melanie; Zeller, Andreas; Singer, Thomas; Gocke, Elmar

    2012-07-04

    Neutral red (Nr) is relatively non-toxic and is widely used as indicator dye in many biological test systems. It absorbs visible light and is known to act as a photosensitizer, involving the generation of reactive oxygen species (type-I reaction) and singlet oxygen (type-II reaction). The mutagenicity of Nr was determined in the Ames test (with Salmonella typhimurium strains TA1535, TA97, TA98, TA98NR, TA100, and TA102) with and without metabolic activation, and with and without photo-activation on agar plates. Similarly to the situation following metabolic activation, photo-mutagenicity of Nr was seen with all Salmonella strains tested, albeit with different effects between these strains. To our knowledge, Nr is the only photo-mutagen showing such a broad action. Since the effects are also observed in strains not known to be responsive to ROS, this indicates that ROS production is not the sole mode of action that leads to photo-genotoxicity. The reactive species produced by irradiation are short-lived as pre-irradiation of an Nr solution did not produce mutagenic effects when added to the bacteria. In addition, mutagenicity in TA98 following irradiation was stronger than in the nitroreductase-deficient strain TA98NR, indicating that nitro derivatives that are transformed by bacterial nitroreductase to hydroxylamines appear to play a role in the photo-mutagenicity of Nr. Photo-genotoxicity of Nr was further investigated in the comet assay and micronucleus test in L5178Y cells. Concentration-dependent increases in primary DNA damage and in the frequency of micronuclei were observed after irradiation.

  7. Genotoxic Evaluation of Mexican Welders Occupationally Exposed to Welding-Fumes Using the Micronucleus Test on Exfoliated Oral Mucosa Cells: A Cross-Sectional, Case-Control Study

    PubMed Central

    Jara-Ettinger, Ana Cecilia; López-Tavera, Juan Carlos; Zavala-Cerna, María Guadalupe; Torres-Bugarín, Olivia

    2015-01-01

    Background An estimated 800,000 people worldwide are occupationally exposed to welding-fumes. Previous studies show that the exposure to such fumes is associated with damage to genetic material and increased cancer risk. In this study, we evaluate the genotoxic effect of welding-fumes using the Micronucleus Test on oral mucosa cells of Mexican welders. Material and Methods We conducted a cross-sectional, matched case-control study of n = 66 (33 exposed welders, and 33 healthy controls). Buccal mucosa smears were collected and stained with acridine orange, observed under 100x optical amplification with a fluorescence lamp, and a single-blinded observer counted the number of micronuclei and other nuclear abnormalities per 2,000 observed cells. We compared the frequencies of micronuclei and other nuclear abnormalities, and fitted generalised linear models to investigate the interactions between nuclear abnormalities and the exposure to welding-fumes, while controlling for smoking and age. Results Binucleated cells and condensed-chromatin cells showed statistically significant differences between cases and controls. The frequency of micronuclei and the rest of nuclear abnormalities (lobed-nuclei, pyknosis, karyolysis, and karyorrhexis) did not differ significantly between the groups. After adjusting for smoking, the regression results showed that the occurrence of binucleated cells could be predicted by the exposure to welding-fumes plus the presence of tobacco consumption; for the condensed-chromatin cells, our model showed that the exposure to welding-fumes is the only reliable predictor. Conclusions Our findings suggest that Mexican welders who are occupationally exposed to welding-fumes have increased counts of binucleated and condensed-chromatin cells. Nevertheless, the frequencies of micronuclei and the rest of nuclear abnormalities did not differ between cases and controls. Further studies should shed more light on this subject. PMID:26244938

  8. Comparative evaluation of genotoxicity by micronucleus assay in the buccal mucosa over comet assay in peripheral blood in oral precancer and cancer patients.

    PubMed

    Katarkar, Atul; Mukherjee, Sanjit; Khan, Masood H; Ray, Jay G; Chaudhuri, Keya

    2014-09-01

    Early detection and quantification of DNA damage in oral premalignancy or malignancy may help in management of the disease and improve survival rates. The comet assay has been successfully utilised to detect DNA damage in oral premalignant or malignancy. However, due to the invasive nature of collecting blood, it may be painful for many unwilling patients. This study compares the micronucleus (MN) assay in oral buccal mucosa cells with the comet assay in peripheral blood cells in a subset of oral habit-induced precancer and cancer patients. For this, MN assay of exfoliated epithelial cells was compared with comet assay of peripheral blood leucocytes among 260 participants, including those with oral lichen planus (OLP; n = 52), leukoplakia (LPK; n = 51), oral submucous fibrosis (OSF; n = 51), oral squamous cell carcinoma (OSCC; n = 54) and normal volunteers (n = 52). Among the precancer groups, LPK patients showed significantly higher levels of DNA damage as reflected by both comet tail length (P < 0.0001) and micronuclei (MNi) frequency (P = 0.0009). The DNA damage pattern in precancer and cancer patients was OLP < OSF < LPK < OSCC, and with respective oral habits, it was multiple habits > cigarette + khaini > cigarette smokers > areca + khaini > areca. There was no significant difference in the comet length and MNi frequency between males and females who had oral chewing habits. An overall significant correlation was observed between MNi frequency and comet tail length with r = 0.844 and P < 0.0001. Thus, the extent of DNA damage evaluation by the comet assay in peripheral blood cells is perfectly reflected by the MN assay on oral exfoliated epithelial cells, and MNi frequency can be used with the same effectiveness and greater efficiency in early detection of oral premalignant conditions.

  9. Micronucleus induction in cells co-exposed in vitro to 50 Hz magnetic field and benzene, 1,4-benzenediol (hydroquinone) or 1,2,4-benzenetriol.

    PubMed

    Pasquini, R; Villarini, M; Scassellati Sforzolini, G; Fatigoni, C; Moretti, M

    2003-01-01

    The generation, transmission (e.g. power lines, transformers, service wires, and electrical panels), and use (e.g. home appliances, such as electric blankets, shavers, and televisions) of electrical energy is associated with the production of weak electric and magnetic fields (EMF) which oscillate 50 (Europe) or 60 (USA) times per second (power-line frequency), falling in the extremely-low frequency (ELF) region of the electromagnetic spectrum. Epidemiological reports suggest a possible association between exposure to ELF-EMF and an increased risk of cancer (e.g. childhood acute leukaemia). Benzene is an established human leukomogen. This xenobiotic, which is unlikely to be the ultimate carcinogen, is metabolized in the liver to its primary metabolite phenol, which is hydroxylated to hydroquinone (1,4-benzenediol) and 1,2,4-benzenetriol. In this in vitro approach, to test the genotoxic and / or co-genotoxic potency of ELF-EMF, the cytokinesis block micronucleus (MN) method with Jurkat cells has been used. A 50 Hz magnetic field (MF) of 5 mT field strength was applied for different length of time (from 1 to 24 h), either alone or with benzene, 1,4-benzenediol, or 1,2,4-benzenetriol. Our preliminary results show that, after 24 h exposure, the frequency of micronucleated cells in MF-exposed cultures is 1.9 fold higher than in sham-exposed (control) cultures. Benzene exposure does not show any cytogenetic activity, whereas 1,4-benzenediol or 1,2,4-benzenetriol alone significantly affect the number of MN in Jurkat cells, as compared to untreated cultures. Moreover, co-exposure to ELF-MF does not seem to affect the frequency of micronuclei induced by benzene, 1,4-benzenediol, or 1,2,4-benzenetriol.

  10. Effect of docosahexaenoic acid and furan fatty acids on cytokinesis block micronucleus cytome assay biomarkers in astrocytoma cell lines under conditions of oxidative stress.

    PubMed

    Chua, Ann; Thomas, Philip; Wijesundera, Chakra; Clifton, Peter; Fenech, Michael

    2014-08-01

    Fatty acids from fish such as docosahexaenoic acid (DHA) are associated with improved brain function, whereas furan fatty acids (FFAs) also found in fish oil at low levels (1%) are thought to have antioxidant properties. Understanding their effects in astrocytes is important as these cells are responsible for maintaining healthy neurons via lipid homeostasis and distribution within the brain, and their decline with aging is a possible cause of dementia. We investigated the cytotoxic and genotoxic effects of DHA and FFA using the cytokinesis-block micronucleus cytome assay in in vitro cultures of U87MG (APOE ɛ3/ɛ3) and U118MG (APOE ɛ2/ɛ4) astrocytoma cell lines with and without a hydrogen peroxide (H2O2, 100 µM) challenge. U118MG was found to be more sensitive to the cytostatic, cytotoxic (i.e., apoptosis), and DNA damaging effects [micronuclei (MNi), nucleoplasmic bridges (NPBs), and nuclear buds (NBUDs)] of H2O2 (P < 0.01 and P < 0.001) when compared with U87MG. DHA at 100 µg/mL significantly affected cytostasis (P < 0.05) and increased DNA damage in the form of NPBs and MNi (P < 0.05) in both cell lines, whereas it decreased necrosis (P = 0.0251) in U87MG. Significant DHA-H2O2 interactions were observed for decreased necrosis (P = 0.0033) and DNA damage biomarkers (P < 0.0001) in the U87MG cell line and increased cytostasis (P < 0.0001) in the U118MG cell line. The effects of FFA also varied between the cell lines, with significant effects observed in decreased cytostasis (P = 0.0022) in the U87MG cell line, whereas increasing cytostasis (P = 0.0144) in the U118MG cell line. Overall, FFA exerted minimal effects on DNA damage biomarkers.

  11. Micronucleus formation, DNA damage and repair in premenopausal women chronically exposed to high level of indoor air pollution from biomass fuel use in rural India.

    PubMed

    Mondal, Nandan Kumar; Mukherjee, Bidisha; Das, Debangshu; Ray, Manas Ranjan

    2010-03-29

    Genotoxicity of indoor air pollution from biomass fuel use has been examined in 132 biomass users (median age 34 years) and 85 age-matched control women from eastern India who used the cleaner fuel liquefied petroleum gas (LPG) to cook. Micronucleus (MN) frequency was evaluated in buccal (BEC) and airway epithelial cells (AEC); DNA damage was examined by comet assay in peripheral blood lymphocytes (PBL); and expressions of gamma-H2AX, Mre11 and Ku70 proteins were localized in AEC and PBL by immunocytochemistry. Reactive oxygen species (ROS) generation in leukocytes was measured by flow cytometry, and the levels of superoxide dismutase (SOD) and total antioxidant status (TAS) in blood were measured by spectrophotometry. Real-time aerosol monitor was used to measure particulate pollutants in indoor air. Compared with controls, biomass users had increased frequencies of micronucleated cells in BEC (3.5 vs. 1.7, p<0.001) and AEC (4.54 vs. 1.86, p<0.001), and greater comet tail % DNA (18.6 vs. 11.7%, p<0.01), tail length (45.5 vs. 31.4mum, p<0.01) and olive tail moment (4.0 vs. 1.4, p<0.01) in PBL. Moreover, biomass users had more gamma-H2AX-positive nuclei in PBL (49.5 vs. 8.5%, p<0.01) and AEC (11.3 vs. 2.9%, p<0.01) along with higher expression of DNA repair proteins Mre11 and Ku70 in these cells, suggesting stimulation of DNA repair mechanism. Biomass users showed rise in ROS generation and depletion of SOD and TAS. Biomass-using households had 2-4 times more particulate matter with diameter less than 10 and 2.5mum in indoor air, and MN frequency and comet tail % DNA were positively associated with these pollutants after controlling potential confounders. Thus, chronic exposure to biomass smoke causes chromosomal and DNA damage and upregulation of DNA repair mechanism.

  12. Relative sensitivity of fish and mammalian cells to the antibiotic, trimethoprim: cytotoxic and genotoxic responses as determined by neutral red retention, Comet and micronucleus assays.

    PubMed

    Papis, Elena; Davies, Simon J; Jha, Awadhesh N

    2011-01-01

    Relative cytotoxicity and genotoxicity of a widely used antibiotic, trimethoprim (TRIMP) was evaluated under in vitro conditions using rainbow trout gonad-2 (RTG-2) and Chinese hamster ovary-K1 (CHO-K1) cells. Whilst cytotoxicity was determined using neutral red retention (NRR) assay, the genotoxicity was determined using single cell gel electrophoresis or the Comet assay and cytokinesis-block micronucleus (CBMN) assay. For NRR assay, concentration-dependent cytotoxic effect was observed for both the cell lines (estimated EC(50) values: 671.82 ± 21.78 and 611.6 ± 20.4 μg ml(-1) for RTG-2 and CHO-K1 cells, respectively). There was no statistically significant difference between the two cell lines for this assay. For the Comet assay, standard 6 h exposure to TRIMP did not show any positive response for any of the cell types used. However, 48 h exposure to RTG-2 cells showed a concentration-dependent induction of DNA damage (r = 0.86). The highest concentration of TRIMP used (i.e. 100 μg ml(-1)) showed relatively higher DNA damage, compared to ethyl methane sulfonate (EMS; 1 μg ml(-1) or 8 mM), a reference genotoxic agent, used concurrently. In contrast, 24 h exposure time for CHO-K1 cells did not show any concentration-dependent increase for this assay. For MN assay, a significant correlation was found between the MN induction and TRIMP concentration for both the cell lines (RTG-2: r = 0.68; CHO-K1: r = 0.79), although only the highest concentration used showed a significant increase for binucleated (BN) cell with micronuclei (BNMN). The study suggests that whilst the cells of different origin could exhibit similar cytotoxicity, they could display differential genotoxic effects. Furthermore, genotoxic effects of TRIMP are primarily exposure period dependent phenomena and, in addition to inhibiting the action of dihydrofolate reductase, oxidative stress could also contribute for the observed toxic effects, fish cells in general being more sensitive for genotoxic

  13. Response of thyroid follicular cells to gamma irradiation compared to proton irradiation. I. Initial characterization of DNA damage, micronucleus formation, apoptosis, cell survival, and cell cycle phase redistribution

    NASA Technical Reports Server (NTRS)

    Green, L. M.; Murray, D. K.; Bant, A. M.; Kazarians, G.; Moyers, M. F.; Nelson, G. A.; Tran, D. T.

    2001-01-01

    The RBE of protons has been assumed to be equivalent to that of photons. The objective of this study was to determine whether radiation-induced DNA and chromosome damage, apoptosis, cell killing and cell cycling in organized epithelial cells was influenced by radiation quality. Thyroid-stimulating hormone-dependent Fischer rat thyroid cells, established as follicles, were exposed to gamma rays or proton beams delivered acutely over a range of physical doses. Gamma-irradiated cells were able to repair DNA damage relatively rapidly so that by 1 h postirradiation they had approximately 20% fewer exposed 3' ends than their counterparts that had been irradiated with proton beams. The persistence of free ends of DNA in the samples irradiated with the proton beam implies that either more initial breaks or a quantitatively different type of damage had occurred. These results were further supported by an increased frequency of chromosomal damage as measured by the presence of micronuclei. Proton-beam irradiation induced micronuclei at a rate of 2.4% per gray, which at 12 Gy translated to 40% more micronuclei than in comparable gamma-irradiated cultures. The higher rate of micronucleus formation and the presence of larger micronuclei in proton-irradiated cells was further evidence that a qualitatively more severe class of damage had been induced than was induced by gamma rays. Differences in the type of damage produced were detected in the apoptosis assay, wherein a significant lag in the induction of apoptosis occurred after gamma irradiation that did not occur with protons. The more immediate expression of apoptotic cells in the cultures irradiated with the proton beam suggests that the damage inflicted was more severe. Alternatively, the cell cycle checkpoint mechanisms required for recovery from such damage might not have been invoked. Differences based on radiation quality were also evident in the alpha components of cell survival curves (0.05 Gy(-1) for gamma rays, 0

  14. Analysis of chromosomal damage after in vivo exposure to 56Fe ions by means of mFISH and micronucleus methods

    NASA Astrophysics Data System (ADS)

    Rithidech, Kanokporn Noy; Supanpaiboon, Wisa; Honikel, Louise; Whorton, Elbert B.

    In this study, we examined the induction of chromosomal damage at day 7 following whole-body exposure of male CBA/CaJ mice to different doses of 1 GeV/amu 56Fe ions (0, 0.1, 0.5, and 1.0 Gy) or 137Cs γ rays as the reference radiation (0, 0.5, 1.0, and 3.0 Gy, using a GammaCell40). Two cytogenetic assays were used to evaluate dose-response relationships for the induction of chromosomal damage. These include: (1) the whole-genome multi-color fluorescence in situ hybridization (mFISH) technique to examine chromosomal damage in metaphases prepared from bone marrow (BM) cells and (2) the mouse in vivo micronucleus (MN) assay to evaluate chromosomal damage (induced in the bone marrow) in blood erythrocytes. By means of the mFISH method, we detected all types of aberrations from mice exposed to either 56Fe ions or 137Cs γ rays. These were translocations (Robertsonian, reciprocal and incomplete one-way types), dicentrics and breaks (both chromatid- and chromosome-types). Each type of radiation-induced significant dose-dependent increases ( ANOVA, p < 0.01) in the frequencies of chromosomal damage (including the numbers of abnormal cells). Our data indicated that the 56Fe ions were more effective (per unit dose) than 137Cs γ rays in inducing damage: about four times for abnormal cells or breaks (both chromatid- and chromosome-types), and 1.6 times for exchanges (all types). Complex chromosome rearrangements were also found in BM cells of mice exposed to 1.0 Gy of 56Fe ions or 3.0 Gy of 137Cs γ rays, but their frequencies were low. Moreover, the frequencies of complex exchanges found at day 7 after exposure of mice to 1.0 Gy of 56Fe ions or 3.0 Gy of 137Cs γ rays were similar. By means of the blood MN assay, we detected dose-dependent increases in the frequencies of MN in normochromatic erythrocytes (NCE or mature red blood cells) at day 7 following in vivo exposure to 56Fe ions or 137Cs γ rays. In contrast, only a slight increase in the frequency of MN in

  15. In situ biomonitoring of the genotoxic effects of mixed industrial emissions using the Tradescantia micronucleus and pollen abortion tests with wild life plants: demonstration of the efficacy of emission controls in an eastern European city.

    PubMed

    Misík, Miroslav; Micieta, Karol; Solenská, Martina; Misíková, Katarína; Pisarcíková, Helena; Knasmüller, Siegfried

    2007-01-01

    Aim of the study was to monitor changes of genotoxic activity of urban air caused by an incinerator and a petrochemical plant in Tradescantia micronucleus (Trad-MCN) and pollen fertility assays with wild plants (Chelidonium majus, Clematis vitalba, Cichorium intybus, Linaria vulgaris, Robinia pseudoacacia). While in the first sampling period (1997-2000) significantly (on average 80%) more MN were found at the polluted site in comparison to controls from a rural area, no significant effects were observed during a later period (between 2003 and 2005). A similar pattern was observed in the pollen abortion assays in which the most pronounced effects were found in chicory and false acacia. The differences of the results obtained in the two periods can be explained by a substantial reduction of air pollution by use of new technologies. In particular the decrease of SO(2) emissions may account for the effects seen in the present study.

  16. Contribution of ionic silver to genotoxic potential of nanosilver in human liver HepG2 and colon Caco2 cells evaluated by the cytokinesis-block micronucleus assay.

    PubMed

    Sahu, Saura C; Roy, Shambhu; Zheng, Jiwen; Ihrie, John

    2016-04-01

    Extensive human exposure to food- and cosmetics-related consumer products containing nanosilver is of public concern because of the lack of information about their safety. Genotoxicity is an important endpoint for the safety and health hazard assessment of regulated products including nanomaterials. The in vitro cytokinesis-block micronucleus (CBMN) assay is a very useful test for predictive genotoxicity testing. Recently, we have reported the genotoxicity of 20 nm nanosilver in human liver HepG2 and colon Caco2 cells evaluated using the CBMN assay. The objective of our present study was three-fold: (i) to evaluate if HepG2 and Caco2 cells are valuable in vitro models for rapid genotoxicity screening of nanosilver; (ii) to test the hypothesis that the nanoparticle size and cell types are critical determinants of its genotoxicity; and (iii) to determine if ionic silver contributes to the nanosilver genotoxicity. With these objectives in mind, we evaluated the genotoxic potential of 50 nm nanosilver of the same shape, composition, surface charge, obtained from the same commercial source, under the same experimental conditions and the same genotoxic CBMN endpoint used for the previously tested 20 nm silver. The ionic silver (silver acetate) was also evaluated under the same conditions. Results of our study show that up to the concentrations tested in these cell types, the smaller (20 nm) nanosilver induces micronucleus formation in both the cell types but the larger (50 nm) nanosilver and the ionic silver provide a much weaker response compared with controls under the same conditions.

  17. Evaluation of the genotoxic and antigenotoxic effects of Chios mastic water by the in vitro micronucleus test on human lymphocytes and the in vivo wing somatic test on Drosophila.

    PubMed

    Vlastos, Dimitris; Mademtzoglou, Despoina; Drosopoulou, Elena; Efthimiou, Ioanna; Chartomatsidou, Tatiana; Pandelidou, Christina; Astyrakaki, Melina; Chalatsi, Eleftheria; Mavragani-Tsipidou, Penelope

    2013-01-01

    Chios mastic gum, a plant-derived product obtained by the Mediterranean bush Pistacia lentiscus (L.) var. chia (Duham), has generated considerable interest because of its antimicrobial, anticancer, antioxidant and other beneficial properties. Its aqueous extract, called Chios mastic water (CMW), contains the authentic mastic scent and all the water soluble components of mastic. In the present study, the potential genotoxic activity of CMW, as well as its antigenotoxic properties against the mutagenic agent mitomycin-C (MMC), was evaluated by employing the in vitro Cytokinesis Block MicroNucleus (CBMN) assay and the in vivo Somatic Mutation And Recombination Test (SMART). In the former assay, lymphocytes were treated with 1, 2 and 5% (v/v) of CMW with or without MMC at concentrations 0.05 and 0.50 µg/ml. No significant micronucleus induction was observed by CMW, while co-treatment with MMC led to a decrease of the MMC-induced micronuclei, which ranged between 22.8 and 44.7%. For SMART, larvae were treated with 50 and 100% (v/v) CMW with or without MMC at concentrations 1.00, 2.50 and 5.00 µg/ml. It was shown that CMW alone did not modify the spontaneous frequencies of spots indicating lack of genotoxic activity. Τhe simultaneous administration of MMC with 100% CMW led to considerable alterations of the frequencies of MMC-induced wing spots with the total mutant clones showing reduction between 53.5 and 74.4%. Our data clearly show a protective role of CMW against the MMC-induced genotoxicity and further research on the beneficial properties of this product is suggested.

  18. Inter-laboratory consistency and variability in the buccal micronucleus cytome assay depends on biomarker scored and laboratory experience: results from the HUMNxl international inter-laboratory scoring exercise.

    PubMed

    Bolognesi, Claudia; Knasmueller, Siegfried; Nersesyan, Armen; Roggieri, Paola; Ceppi, Marcello; Bruzzone, Marco; Blaszczyk, Ewa; Mielzynska-Svach, Danuta; Milic, Mirta; Bonassi, Stefano; Benedetti, Danieli; Da Silva, Juliana; Toledo, Raphael; Salvadori, Daisy Maria Fávero; de Restrepo, Helena Groot; Filipic, Metka; Hercog, Klara; Aktaş, Ayça; Burgaz, Sema; Kundi, Michael; Grummt, Tamara; Thomas, Philip; Hor, Maryam; Escudero-Fung, Maria; Holland, Nina; Fenech, Michael

    2016-09-26

    The buccal micronucleus cytome (BMNcyt) assay in uncultured exfoliated epithelial cells from oral mucosa is widely applied in biomonitoring human exposures to genotoxic agents and is also proposed as a suitable test for prescreening and follow-up of precancerous oral lesions. The main limitation of the assay is the large variability observed in the baseline values of micronuclei (MNi) and other nuclear anomalies mainly related to different scoring criteria. The aim of this international collaborative study, involving laboratories with different level of experience, was to evaluate the inter- and intra-laboratory variations in the BMNcyt parameters, using recently implemented guidelines, in scoring cells from the same pooled samples obtained from healthy subjects (control group) and from cancer patients undergoing radiotherapy (treated group). The results indicate that all laboratories correctly discriminated samples from the two groups by a significant increase of micronucleus (MN) and nuclear bud (NBUD) frequencies and differentiated binucleated (BN) cells, associated with the exposure to ionizing radiation. The experience of the laboratories was shown to play an important role in the identification of the different cell types and nuclear anomalies. MN frequency in differentiated mononucleated (MONO) and BN cells showed the greatest consistency among the laboratories and low variability was also detected in the frequencies of MONO and BN cells. A larger variability was observed in classifying the different cell types, indicating the subjectivity in the interpretation of some of the scoring criteria while reproducibility of the results between scoring sessions was very good. An inter-laboratory calibration exercise is strongly recommended before starting studies with BMNcyt assay involving multiple research centers.

  19. Cigarette smoke induced genotoxicity and respiratory tract pathology: evidence to support reduced exposure time and animal numbers in tobacco product testing.

    PubMed

    Dalrymple, Annette; Ordoñez, Patricia; Thorne, David; Walker, David; Camacho, Oscar M; Büttner, Ansgar; Dillon, Debbie; Meredith, Clive

    2016-06-01

    Many laboratories are working to develop in vitro models that will replace in vivo tests, but occasionally there remains a regulatory expectation of some in vivo testing. Historically, cigarettes have been tested in vivo for 90 days. Recently, methods to reduce and refine animal use have been explored. This study investigated the potential of reducing animal cigarette smoke (CS) exposure to 3 or 6 weeks, and the feasibility of separate lung lobes for histopathology or the Comet assay. Rats were exposed to sham air or CS (1 or 2 h) for 3 or 6 weeks. Respiratory tissues were processed for histopathological evaluation, and Alveolar type II cells (AEC II) isolated for the Comet assay. Blood was collected for Pig-a and micronucleus quantification. Histopathological analyses demonstrated exposure effects, which were generally dependent on CS dose (1 or 2 h, 5 days/week). Comet analysis identified that DNA damage increased in AEC II following 3 or 6 weeks CS exposure, and the level at 6 weeks was higher than 3 weeks. Pig-a mutation or micronucleus levels were not increased. In conclusion, this study showed that 3 weeks of CS exposure was sufficient to observe respiratory tract pathology and DNA damage in isolated AEC II. Differences between the 3 and 6 week data imply that DNA damage in the lung is cumulative. Reducing exposure time, plus analyzing separate lung lobes for DNA damage or histopathology, supports a strategy to reduce and refine animal use in tobacco product testing and is aligned to the 3Rs (replacement, reduction and refinement).

  20. Cigarette smoke induced genotoxicity and respiratory tract pathology: evidence to support reduced exposure time and animal numbers in tobacco product testing

    PubMed Central

    Dalrymple, Annette; Ordoñez, Patricia; Thorne, David; Walker, David; Camacho, Oscar M.; Büttner, Ansgar; Dillon, Debbie; Meredith, Clive

    2016-01-01

    Abstract Many laboratories are working to develop in vitro models that will replace in vivo tests, but occasionally there remains a regulatory expectation of some in vivo testing. Historically, cigarettes have been tested in vivo for 90 days. Recently, methods to reduce and refine animal use have been explored. This study investigated the potential of reducing animal cigarette smoke (CS) exposure to 3 or 6 weeks, and the feasibility of separate lung lobes for histopathology or the Comet assay. Rats were exposed to sham air or CS (1 or 2 h) for 3 or 6 weeks. Respiratory tissues were processed for histopathological evaluation, and Alveolar type II cells (AEC II) isolated for the Comet assay. Blood was collected for Pig-a and micronucleus quantification. Histopathological analyses demonstrated exposure effects, which were generally dependent on CS dose (1 or 2 h, 5 days/week). Comet analysis identified that DNA damage increased in AEC II following 3 or 6 weeks CS exposure, and the level at 6 weeks was higher than 3 weeks. Pig-a mutation or micronucleus levels were not increased. In conclusion, this study showed that 3 weeks of CS exposure was sufficient to observe respiratory tract pathology and DNA damage in isolated AEC II. Differences between the 3 and 6 week data imply that DNA damage in the lung is cumulative. Reducing exposure time, plus analyzing separate lung lobes for DNA damage or histopathology, supports a strategy to reduce and refine animal use in tobacco product testing and is aligned to the 3Rs (replacement, reduction and refinement). PMID:27160659

  1. Studies of the toxicological potential of tripeptides (L-valyl-L-prolyl-L-proline and L-isoleucyl-L-prolyl-L-proline): VII. Micronucleus test of tripeptides-containing casein hydrolysate and Lactobacillus helveticus-fermented milk powders in rats and mice.

    PubMed

    Matsuura, Keiichi; Mennear, John H; Maeno, Masafumi; Bernard, Bruce K

    2005-01-01

    The objective of these in vivo experiments was to assess the mutagenic potential of tripeptides as reflected by the ability of the test compound to induce the formation of micronuclei in mouse polychromatic erythrocytes. The test agents used in these experiments were (1) powdered Aspergillus oryzae protease casein hydrolysate (CH) and (2) powdered Lactobacillus helveticus-fermented milk (FM). Both test agents contain two tripeptides, L-valyl-L-prolyl-L-proline (VPP) and L-isoleucyl-L-prolyl-L-proline (IPP). Male Sprague-Dawley rats (five per group) were administered doses of 0, 500, 1000, or 2000 mg (0, 3, 6, or 12 mg VPP plus IPP)/kg body weight (BW)/day CH by oral gavage for 2 days. Male CD-1 mice (six per group) received a single oral gavage dose of 0, 500, 1000, or 2000 mg (0, 0.8, 1.6 or 3.3 mg VPP plus IPP)/kg BW of FM. Positive-control agents were cyclophosphamide (10 mg/kg, intraperitoneal [i.p.]) in rats and mitocycin C (2 mg/kg, i.p.) in mice. Twenty-four hours after the second dose of CH, or the dose of cyclophosphamide to rats, or FM or mitocycin C to mice, bone marrow cells were fixed and examined for the presence of polychromatic erythrocytes (PCEs) and the presence or absence of micronucleated PCEs (MNPCEs). Administration of CH to rats and FM to mice produced neither changes in body weights nor signs of systemic toxicity. Similarly, neither CH nor FM caused statistically significant variations in the incidences of either PCEs or MNPCEs. Both positive-control agents caused unequivocal increases in the incidence of MNPCEs and cyclophosphamide significantly reduced the percent of rat erythrocytes appearing as PCEs. The results of these micronucleus assays conducted with either powdered CH or FM in rats and mice, respectively, show that neither form of the tripeptides possesses the potential to induce micronuclei formation in these rodent species.

  2. A protocol for the in vitro micronucleus test. I. Contributions to the development of a protocol suitable for regulatory submissions from an examination of 16 chemicals with different mechanisms of action and different levels of activity.

    PubMed

    Garriott, Michael L; Phelps, J Barry; Hoffman, Wherly P

    2002-05-27

    The in vitro micronucleus (IVM) test is currently used as a screen during the early stages of pharmaceutical development to identify chemicals likely to produce positive outcomes in the in vitro chromosome aberration assay. For several reasons, the assay is being considered as an alternative to the aberration assay, but the current screening protocols are not rigorous enough to fully satisfy concerns about genotoxic safety. This manuscript describes the investigation of several protocol parameters to assist with the development of a regulatory guideline for the IVM test. The parameters investigated are: the effect of cytochalasin B on the outcome of the assay when conducted with continually growing cell lines; the need for an extended exposure in the absence of metabolic activation; and the number of cells to be counted for a valid assay. In addition, two statistical procedures for the analysis of data from the test are described. The results of the investigation indicate that cytochalasin B does not effect the outcome of the test, that the extended exposure treatment is not necessary, that counting 2000 cells is preferable to counting 1000, and that the data can be appropriately analyzed using a trend test.

  3. Assessment of the genotoxic potential of two zinc oxide sources (amorphous and nanoparticles) using the in vitro micronucleus test and the in vivo wing somatic mutation and recombination test.

    PubMed

    Reis, Érica de Melo; de Rezende, Alexandre Azenha Alves; Santos, Diego Vilela; de Oliveria, Pollyanna Francielli; Nicolella, Heloisa Diniz; Tavares, Denise Crispim; Silva, Anielle Christine Almeida; Dantas, Noelio Oliveira; Spanó, Mário Antônio

    2015-10-01

    In this study, we evaluated the toxic and genotoxic potential of zinc oxide nanoparticles (ZnO NPs) of 20 nm and the mutagenic potential of these ZnO NPs as well as that of an amorphous ZnO. Toxicity was assessed by XTT colorimetric assay. ZnO NPs were toxic at concentrations equal to or higher than 240.0 μM. Genotoxicity was assessed by in vitro Cytokinesis Block Micronucleus Assay (CBMN) in V79 cells. ZnO NPs were genotoxic at 120.0 μM. The mutagenic potential of amorphous ZnO and the ZnO NPs was assayed using the wing Somatic Mutation and Recombination Test (SMART) of Drosophila melanogaster. In the Standard cross, the amorphous ZnO and ZnO NPs were not mutagenic. Nevertheless, Marker trans-heterozygous individuals from the High bioactivation cross treated with amorphous ZnO (6.25 mM) and ZnO NPs (12.50 mM) displayed a significant increased number of mutant spots when compared with the negative control. In conclusion, the results were not dose related and indicate that only higher concentrations of ZnO NPs were toxic and able to induce genotoxicity in V79 cells. The increase in mutant spots observed in D. melanogaster was generated due to mitotic recombination, rather than mutational events.

  4. Reduce HIV Risk

    MedlinePlus

    ... incidence could be reduced if people changed their sexual behaviors. Our research has demonstrated remarkable success in reducing HIV risk-associated sexual behaviors among African American adolescents and adults." Spring 2008 ...

  5. In vivo rat glandular stomach and colon micronucleus tests: Kinetics of micronucleated cells, apoptosis, and cell proliferation in the target tissues after a single oral administration of stomach- or colon-carcinogens.

    PubMed

    Ohyama, Wakako; Okada, Emiko; Fujiishi, Yohei; Narumi, Kazunori; Yasutake, Nobuyoshi

    2013-08-15

    We have developed in vivo micronucleus (MN) tests by using an epithelial cell suspension isolated from the glandular stomach and colon of rodents. In the present study, our aim was to demonstrate the characteristics of the glandular stomach and colon MN tests by analyzing time-related changes in MN frequencies, apoptosis and cell proliferation in the target tissues of male CD (SD) rats that were orally administered a single dose of a stomach- or colon-targeted carcinogen, i.e., N-nitroso-N-methylurea (MNU) or N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) for the stomach and 1,2-dimethylhydrazine dihydrochloride (DMH) for the colon. After treatment, the MN frequencies significantly increased in the respective target tissues, peaking at 48-96h and decreasing afterwards. The time-response pattern could be explained by the epithelial cell turnover confirmed with a labeling experiment using the thymidine analog, 5-ethynyl-2'-deoxyuridine (EdU). In the study with MNU and DMH, we also prepared paraffin sections of the respective target tissues for the immunohistochemical evaluation of apoptosis and cell proliferation. The incidence of apoptosis increased in the early phase (6 and/or 24h) after treatment, and then decreased. Cell proliferation was depressed when a high incidence of apoptosis was observed, and then it recovered until 72h. MN frequencies increased with the recovery of cell proliferation occurring later than the peak apoptosis response. These results indicated that micronuclei were induced in the glandular stomach and colon epithelial cells by administration of the model chemicals. On the other hand, MNU induced significant increases of MNed cells in both the glandular stomach and bone marrow in the same rats, while MNNG did only in the glandular stomach when administered orally up to 1/4 of the LD50. These results suggest that the glandular stomach- and colon-MN tests would be useful for evaluating the genotoxicity of agents in the gastrointestinal tract.

  6. Chemical genoprotection: reducing biological damage to as low as reasonably achievable levels

    PubMed Central

    Alcaraz, M; Armero, D; Martínez-Beneyto, Y; Castillo, J; Benavente-García, O; Fernandez, H; Alcaraz-Saura, M; Canteras, M

    2011-01-01

    Objectives The aim of this study was to evaluate the antioxidant substances present in the human diet with an antimutagenic protective capacity against genotoxic damage induced by exposure to X-rays in an attempt to reduce biological damage to as low a level as reasonably possible. Methods Ten compounds were assessed using the lymphocyte cytokinesis-block micronucleus (MN) cytome test. The compounds studied were added to human blood at 25 μM 5 min before exposure to irradiation by 2 Gy of X-rays. Results The protective capacity of the antioxidant substances assessed was from highest to lowest according to the frequency of the MN generated by X-ray exposure: rosmarinic acid = carnosic acid = δ-tocopherol = l-acid ascorbic = apigenin = amifostine (P < 0.001) > green tea extract = diosmine = rutin = dimetylsulfoxide (P < 0.05) > irradiated control. The reduction in genotoxic damage with the radiation doses administered reached 58%, which represents a significant reduction in X-ray-induced chromosomal damage (P < 0.001). This degree of protection is greater than that obtained with amifostine, a radioprotective compound used in radiotherapy and which is characterised by its high toxicity. Conclusion Several antioxidant substances, common components of the human diet and lacking toxicity, offer protection from the biological harm induced by ionizing radiation. Administering these protective substances to patients before radiological exploration should be considered, even in the case of small radiation doses and regardless of the biological damage expected. PMID:21697157

  7. Reducing Teacher Incompetence.

    ERIC Educational Resources Information Center

    Rich, John Martin

    1988-01-01

    Suggests how administrators may reduce teacher incompetence. Teacher incompetence can be reduced if administrators fully understand and undertake appropriate preventive and remedial measures. Two sections comprise this article. First, a taxonomy of teacher incompetence reveals the magnitude of the problem. Second, preventive and remedial measures…

  8. Reducible oxide based catalysts

    DOEpatents

    Thompson, Levi T.; Kim, Chang Hwan; Bej, Shyamal K.

    2010-04-06

    A catalyst is disclosed herein. The catalyst includes a reducible oxide support and at least one noble metal fixed on the reducible oxide support. The noble metal(s) is loaded on the support at a substantially constant temperature and pH.

  9. Reducing Childhood Obesity

    MedlinePlus

    ... Navigation Bar Home Current Issue Past Issues Reducing Childhood Obesity Past Issues / Summer 2007 Table of Contents For ... page please turn Javascript on. The We Can! childhood obesity-prevention program involves parents, caregivers, and community leaders ...

  10. Reduced shear power spectrum

    SciTech Connect

    Dodelson, Scott; Shapiro, Charles; White, Martin J.; /UC, Berkeley, Astron. Dept. /UC, Berkeley

    2005-08-01

    Measurements of ellipticities of background galaxies are sensitive to the reduced shear, the cosmic shear divided by (1-{kappa}) where {kappa} is the projected density field. They compute the difference between shear and reduced shear both analytically and with simulations. The difference becomes more important an smaller scales, and will impact cosmological parameter estimation from upcoming experiments. A simple recipe is presented to carry out the required correction.

  11. Reduced Magmatic Volatiles

    NASA Astrophysics Data System (ADS)

    Hirschmann, M. M.; Withers, A. C.; Ardia, P.; Stanley, B. D.; Foley, N.

    2012-12-01

    Volatiles in Earth's upper mantle are dominated by H2O and CO2, but under more reduced conditions likely deeper in the mantle, other volatile species may be important or dominant. However, the speciation, solubilities, and effect on physical properties of reduced magmatic volatiles are poorly constrained. Here we summarize results from an experimental campaign to better understand reduced volatiles in magmas. Experiments emphasize spectroscopic and SIMS characterization of dissolved species in experiments for which fluid fugacities are known, thereby facilitating thermodynamic parameterization. Experimental determinations of molecular H2 solubility in basaltic and andesitic liquids show concentrations that are proportional to H2 fugacity. Because H2 increases with fH2 whereas dissolved H2O increases with fH2O1/2, the relative importance of H2 increases with pressure and for more hydrous magmas. At 1 GPa and IW-1, solubility in basalt reaches 0.3 wt.% (equivalent to 2.7 wt.% H2O). Solubilities at pressures of the deep upper mantle have not been explored experimentally (as is also true for H2O and CO2), but H2 could become the dominant hydrous species at 400 km and deeper, and so deep hydrous melts may have chiefly H2 rather than H2O or OH. Experiments suggest an extremely low partial specific density (0.18 kg/m3) for dissolved H2 at low pressure, and so appreciable dissolved H2 in melt atop the 410 km discontinuity or in the lower mantle may promote positive buoyancy. Solubilities of reduced C-species remain poorly known. In contrast to results in Na2O-SiO2 liquids (Mysen et al., 2009), experiments with a haplobasaltic liquid at controlled CH4 fugacities indicated very small (<0.05 wt.%) CH4 solubilities even at very reduced conditions (reduced conditions and in

  12. Evaluation of the genotoxic and antigenotoxic effects after acute and subacute treatments with açai pulp (Euterpe oleracea Mart.) on mice using the erythrocytes micronucleus test and the comet assay.

    PubMed

    Ribeiro, Juliana Carvalho; Antunes, Lusânia Maria Greggi; Aissa, Alexandre Ferro; Darin, Joana D'arc Castania; De Rosso, Veridiana Vera; Mercadante, Adriana Zerlotti; Bianchi, Maria de Lourdes Pires

    2010-01-01

    Açai, the fruit of a palm native to the Amazonian basin, is widely distributed in northern South America, where it has considerable economic importance. Whereas individual polyphenolics compounds in açai have been extensively evaluated, studies of the intact fruit and its biological properties are lacking. Therefore, the present study was undertaken to investigate the in vivo genotoxicity of açai and its possible antigenotoxicity on doxorubicin (DXR)-induced DNA damage. The açai pulp doses selected were 3.33, 10.0 and 16.67g/kg b.w. administered by gavage alone or prior to DXR (16mg/kg b.w.) administered by intraperitoneal injection. Swiss albino mice were distributed in eight groups for acute treatment with açai pulp (24h) and eight groups for subacute treatment (daily for 14 consecutive days) before euthanasia. The negative control groups were treated in a similar way. The results of chemical analysis suggested the presence of carotenoids, anthocyanins, phenolic, and flavonoids in açai pulp. The endpoints analyzed were micronucleus induction in bone marrow and peripheral blood cells polychromatic erythrocytes, and DNA damage in peripheral blood, liver and kidney cells assessed using the alkaline (pH >13) comet assay. There were no statistically significant differences (p>0.05) between the negative control and the groups treated with the three doses of açai pulp alone in all endpoints analyzed, demonstrating the absence of genotoxic effects. The protective effects of açai pulp were observed in both acute and subacute treatments, when administered prior to DXR. In general, subacute treatment provided greater efficiency in protecting against DXR-induced DNA damage in liver and kidney cells. These protective effects can be explained as the result of the phytochemicals present in açai pulp. These results will be applied to the developmental of food with functional characteristics, as well as to explore the characteristics of açai as a health promoter.

  13. Tank closure reducing grout

    SciTech Connect

    Caldwell, T.B.

    1997-04-18

    A reducing grout has been developed for closing high level waste tanks at the Savannah River Site in Aiken, South Carolina. The grout has a low redox potential, which minimizes the mobility of Sr{sup 90}, the radionuclide with the highest dose potential after closure. The grout also has a high pH which reduces the solubility of the plutonium isotopes. The grout has a high compressive strength and low permeability, which enhances its ability to limit the migration of contaminants after closure. The grout was designed and tested by Construction Technology Laboratories, Inc. Placement methods were developed by the Savannah River Site personnel.

  14. Reducing Behavior through Reinforcement.

    ERIC Educational Resources Information Center

    Deitz, Diane E. D.; Repp, Alan C.

    1983-01-01

    The use of reinforcement to reduce inappropriate behaviors of mentally retarded and emotionally disturbed students may involve the following procedures: differential reinforcement of low rates of responding (DRL), the differential reinforcement of response omission (DRO), and the differential reinforcement of incompatible (DRI) or alternative…

  15. Please Reduce Cycle Time

    DTIC Science & Technology

    2014-12-01

    Defense AT&L: November–December 2014 4 Please Reduce Cycle Time Brian Schultz “Time is what we want most but what we use worst.” — William Penn ...Schultz is a professor of program management at the Defense Acquisition University’s Mid-Atlantic Region in California, Md. As William Penn noted

  16. Reduced Braginskii equations

    SciTech Connect

    Yagi, M.; Horton, W. )

    1994-07-01

    A set of reduced Braginskii equations is derived without assuming flute ordering and the Boussinesq approximation. These model equations conserve the physical energy. It is crucial at finite [beta] that the perpendicular component of Ohm's law be solved to ensure [del][center dot][bold j]=0 for energy conservation.

  17. Demonstrating Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Pearlman, Howard; Stocker, Dennis; Gotti, Daniel; Urban, David; Ross, Howard; Sours, Thomas

    1996-01-01

    A miniature drop tower, Reduced-Gravity Demonstrator is developed to illustrate the effects of gravity on a variety of phenomena including the way fluids flow, flames burn, and mechanical systems (such as pendulum) behave. A schematic and description of the demonstrator and payloads are given, followed by suggestions for how one can build his (her) own.

  18. Reducing float coal dust

    PubMed Central

    Patts, J.R.; Colinet, J.F.; Janisko, S.J.; Barone, T.L.; Patts, L.D.

    2016-01-01

    Controlling float coal dust in underground coal mines before dispersal into the general airstream can reduce the risk of mine explosions while potentially achieving a more effective and efficient use of rock dust. A prototype flooded-bed scrubber was evaluated for float coal dust control in the return of a continuous miner section. The scrubber was installed inline between the face ventilation tubing and an exhausting auxiliary fan. Airborne and deposited dust mass measurements were collected over three days at set distances from the fan exhaust to assess changes in float coal dust levels in the return due to operation of the scrubber. Mass-based measurements were collected on a per-cut basis and normalized on the basis of per ton mined by the continuous miner. The results show that average float coal dust levels measured under baseline conditions were reduced by more than 90 percent when operating the scrubber. PMID:28018004

  19. Reducing rotor weight

    SciTech Connect

    Cheney, M.C.

    1997-12-31

    The cost of energy for renewables has gained greater significance in recent years due to the drop in price in some competing energy sources, particularly natural gas. In pursuit of lower manufacturing costs for wind turbine systems, work was conducted to explore an innovative rotor designed to reduce weight and cost over conventional rotor systems. Trade-off studies were conducted to measure the influence of number of blades, stiffness, and manufacturing method on COE. The study showed that increasing number of blades at constant solidity significantly reduced rotor weight and that manufacturing the blades using pultrusion technology produced the lowest cost per pound. Under contracts with the National Renewable Energy Laboratory and the California Energy Commission, a 400 kW (33m diameter) turbine was designed employing this technology. The project included tests of an 80 kW (15.5m diameter) dynamically scaled rotor which demonstrated the viability of the design.

  20. The combination of two novel tobacco blends and filter technologies to reduce the in vitro genotoxicity and cytotoxicity of prototype cigarettes.

    PubMed

    Crooks, Ian; Scott, Ken; Dalrymple, Annette; Dillon, Debbie; Meredith, Clive

    2015-04-01

    Tobacco smoke from a combustible cigarette contains more than 6000 constituents; approximately 150 of these are identified as toxicants. Technologies that modify the tobacco blend to reduce toxicant emissions have been developed. These include tobacco sheet substitute to dilute toxicants in smoke and blend treated tobacco to reduce the levels of nitrogenous precursors and some polyphenols. Filter additives to reduce gas (vapour) phase constituents have also been developed. In this study, both tobacco blend and filter technologies were combined into an experimental cigarette and smoked to International Organisation on Standardisation and Health Canada puffing parameters. The resulting particulate matter was subjected to a battery of in vitro genotoxicity and cytotoxicity assays - the Ames test, mouse lymphoma assay, the in vitro micronucleus test and the Neutral Red Uptake assay. The results indicate that cigarettes containing toxicant reducing technologies may be developed without observing new additional genotoxic hazards as assessed by the assays specified. In addition, reductions in bacterial mutagenicity and mammalian genotoxicity of the experimental cigarette were observed relative to the control cigarettes. There were no significant differences in cytotoxicity relative to the control cigarettes.

  1. Reducing teenage pregnancy.

    PubMed

    Fallon, Debbie

    2011-03-01

    The Teenage Pregnancy Independent Advisory Group (TPIAG) was established in 2000 to advise the government about reducing teenage pregnancy rates and supporting teenage parents to continue with their education. The group reached the end of its tenure in December 2010. This short article highlights some of the key issues from the final report and provides some insights into past achievements and future directions from an interview with Gill Frances, TPIAG's chair.

  2. Gradual extinction reduces reinstatement

    PubMed Central

    Shiban, Youssef; Wittmann, Jasmin; Weißinger, Mara; Mühlberger, Andreas

    2015-01-01

    The current study investigated whether gradually reducing the frequency of aversive stimuli during extinction can prevent the return of fear. Thirty-one participants of a three-stage procedure (acquisition, extinction and a reinstatement test on day 2) were randomly assigned to a standard extinction (SE) and gradual extinction (GE) procedure. The two groups differed only in the extinction procedure. While the SE group ran through a regular extinction process without any negative events, the frequency of the aversive stimuli during the extinction phase was gradually reduced for the GE group. The unconditioned stimulus (US) was an air blast (5 bar, 10 ms). A spider and a scorpion were used as conditioned stimuli (CS). The outcome variables were contingency ratings and physiological measures (skin conductance response, SCR and startle response). There were no differences found between the two groups for the acquisition and extinction phases concerning contingency ratings, SCR, or startle response. GE compared to SE significantly reduced the return of fear in the reinstatement test for the startle response but not for SCR or contingency ratings. This study was successful in translating the findings in rodent to humans. The results suggest that the GE process is suitable for increasing the efficacy of fear extinction. PMID:26441581

  3. Reducing Iatrogenic Risks

    PubMed Central

    Ely, E. Wesley; Speroff, Theodore; Pun, Brenda T.; Boehm, Leanne; Dittus, Robert S.

    2010-01-01

    ICUs are experiencing an epidemic of patients with acute brain dysfunction (delirium) and weakness, both associated with increased mortality and long-term disability. These conditions are commonly acquired in the ICU and are often initiated or exacerbated by sedation and ventilation decisions and management. Despite > 10 years of evidence revealing the hazards of delirium, the quality chasm between current and ideal processes of care continues to exist. Monitoring of delirium and sedation levels remains inconsistent. In addition, sedation, ventilation, and physical therapy practices proven successful at reducing the frequency and severity of adverse outcomes are not routinely practiced. In this article, we advocate for the adoption and implementation of a standard bundle of ICU measures with great potential to reduce the burden of ICU-acquired delirium and weakness. Individual components of this bundle are evidence based and can help standardize communication, improve interdisciplinary care, reduce mortality, and improve cognitive and functional outcomes. We refer to this as the “ABCDE bundle,” for awakening and breathing coordination, delirium monitoring, and exercise/early mobility. This evidence-based bundle of practices will build a bridge across the current quality chasm from the “front end” to the “back end” of critical care and toward improved cognitive and functional outcomes for ICU survivors. PMID:21051398

  4. Naval electrochemical corrosion reducer

    DOEpatents

    Clark, Howard L.

    1991-10-01

    A corrosion reducer for use with ships having a hull, a propeller mounted a propeller shaft and extending through the hull, bearings supporting the shaft, at least one thrust bearing and one seal. The improvement includes a current collector and a current reduction assembly for reducing the voltage between the hull and shaft in order to reduce corrosion due to electrolytic action. The current reduction assembly includes an electrical contact, the current collector, and the hull. The current reduction assembly further includes a device for sensing and measuring the voltage between the hull and the shaft and a device for applying a reverse voltage between the hull and the shaft so that the resulting voltage differential is from 0 to 0.05 volts. The current reduction assembly further includes a differential amplifier having a voltage differential between the hull and the shaft. The current reduction assembly further includes an amplifier and a power output circuit receiving signals from the differential amplifier and being supplied by at least one current supply. The current selector includes a brush assembly in contact with a slip ring over the shaft so that its potential may be applied to the differential amplifier.

  5. Reducing Radiation Damage

    SciTech Connect

    Blankenbecler, Richard

    2006-06-05

    This talk describes the use of a modified treatment sequence, i.e., radiation dose, geometry, dwell time, etc., to mitigate some of the deleterious effects of cancer radiotherapy by utilizing natural cell repair processes. If bad side effects can be reduced, a more aggressive therapy can be put into place. Cells contain many mechanisms that repair damage of various types. If the damage can not be repaired, cells will undergo apoptosis (cell death). Data will be reviewed that support the fact that a small dose of radiation will activate damage repair genes within a cell. Once the mechanisms are fully active, they will efficiently repair the severe damage from a much larger radiation dose. The data ranges from experiments on specific cell cultures using microarray (gene chip) techniques to experiments on complete organisms. The suggested effect and treatment is consistent with the assumption that all radiation is harmful, no matter how small the dose. Nevertheless, the harm can be reduced. These mechanisms need to be further studied and characterized. In particular, their time dependence needs to be understood before the proposed treatment can be optimized. Under certain situations it is also possible that the deleterious effects of chemotherapy can be mitigated and the damage to radiation workers can be reduced.

  6. Coating Reduces Ice Adhesion

    NASA Technical Reports Server (NTRS)

    Smith, Trent; Prince, Michael; DwWeese, Charles; Curtis, Leslie

    2008-01-01

    The Shuttle Ice Liberation Coating (SILC) has been developed to reduce the adhesion of ice to surfaces on the space shuttle. SILC, when coated on a surface (foam, metal, epoxy primer, polymer surfaces), will reduce the adhesion of ice by as much as 90 percent as compared to the corresponding uncoated surface. This innovation is a durable coating that can withstand several cycles of ice growth and removal without loss of anti-adhesion properties. SILC is made of a binder composed of varying weight percents of siloxane(s), ethyl alcohol, ethyl sulfate, isopropyl alcohol, and of fine-particle polytetrafluoroethylene (PTFE). The combination of these components produces a coating with significantly improved weathering characteristics over the siloxane system alone. In some cases, the coating will delay ice formation and can reduce the amount of ice formed. SILC is not an ice prevention coating, but the very high water contact angle (greater than 140 ) causes water to readily run off the surface. This coating was designed for use at temperatures near -170 F (-112 C). Ice adhesion tests performed at temperatures from -170 to 20 F (-112 to -7 C) show that SILC is a very effective ice release coating. SILC can be left as applied (opaque) or buffed off until the surface appears clear. Energy dispersive spectroscopy (EDS) and x-ray photoelectron spectroscopy (XPS) data show that the coating is still present after buffing to transparency. This means SILC can be used to prevent ice adhesion even when coating windows or other objects, or items that require transmission of optical light. Car windshields are kept cleaner and SILC effectively mitigates rain and snow under driving conditions.

  7. Modelling reduced sparse data

    NASA Astrophysics Data System (ADS)

    Kozera, Ryszard; Noakes, Lyle

    2016-09-01

    In this paper we discuss the problem of fitting to an ordered collection of points in arbitary Euclidean space called reduced data. We are not given here the corresponding interpolation knots. Instead, these are estimated by new knots upon minimizing a relevant highly nonlinear optimization scheme based on natural spline interpolation. The existence of a global minimizer (i.e. the collection of interpolation knots in ascending order) is also addressed in this paper. Finally, Leap-Frog optimization tool is used to compute these knots approximating the unknown interpolation knots. This numerical scheme is subsequently compared with the Secant Method. Two illustrative examples are given.

  8. Nonlinearity-reduced interferometer

    NASA Astrophysics Data System (ADS)

    Wu, Chien-ming

    2007-12-01

    Periodic nonlinearity is a systematic error limiting the accuracy of displacement measurements at the nanometer level. It results from many causes such as the frequency mixing, polarization mixing, polarization-frequency mixing, and the ghost reflections. An interferometer having accuracy in displacement measurement of less than one-nanometer is necessary in nanometrology. To meet the requirement, the periodic nonlinearity should be less than deep sub-nanometer. In this paper, a nonlinearity-reduced interferometry has been proposed. Both the linear- and straightness-interferometer were tested. The developed interferometer demonstrated of a residual nonlinearity less than 25 pm.

  9. Embodied intervention reduce depression

    NASA Astrophysics Data System (ADS)

    Song, Dong-Qing; Bi, Xin; Fu, Ying

    2011-10-01

    To investigate the difference of the selected-rate of undergraduates' depression with respect to time, gender and scales and the intervention effect of embodied exercise, 201 Undergraduates were measured with Self-Rating Depression Scale and Beck Depression Inventory (BDI).The result shows there are significant difference of the selected-rates of undergraduates' depression resulted from long-time interval rather than from short-time interval and gender. After the intervention, the selected-rates are decreased and no significant difference has been found between the embodied groups and the controlled group. Only the embodied groups maintain the better effects of the intervention in the tracking. Also the result shows that only the participants of embodied groups obtain more positive emotional experience. We conclude that there is significant difference of selected-rate of undergraduates' depression on scales, and the embodied exercise can effectively reduce undergraduate's depression.

  10. Reducing GWAS Complexity

    PubMed Central

    Hazelett, Dennis J.; Conti, David V.; Han, Ying; Al Olama, Ali Amin; Easton, Doug; Eeles, Rosalind A.; Kote-Jarai, Zsofia; Haiman, Christopher A.; Coetzee, Gerhard A.

    2016-01-01

    ABSTRACT Genome-wide association studies (GWAS) have revealed numerous genomic 'hits' associated with complex phenotypes. In most cases these hits, along with surrogate genetic variation as measure by numerous single nucleotide polymorphisms (SNPs) that are in linkage disequilibrium, are not in coding genes making assignment of functionality or causality intractable. Here we propose that fine-mapping along with the matching of risk SNPs at chromatin biofeatures lessen this complexity by reducing the number of candidate functional/causal SNPs. For example, we show here that only on average 2 SNPs per prostate cancer risk locus are likely candidates for functionality/causality; we further propose that this manageable number should be taken forward in mechanistic studies. The candidate SNPs can be looked up for each prostate cancer risk region in 2 recent publications in 20151,2 from our groups. PMID:26771711

  11. Pressure reducing regulator

    DOEpatents

    Whitehead, J.C.; Dilgard, L.W.

    1995-10-10

    A pressure reducing regulator that controls its downstream or outlet pressure to a fixed fraction of its upstream or inlet pressure is disclosed. The regulator includes a housing which may be of a titanium alloy, within which is located a seal or gasket at the outlet end which may be made of annealed copper, a rod, and piston, each of which may be made of high density graphite. The regulator is insensitive to temperature by virtue of being without a spring or gas sealed behind a diaphragm, and provides a reference for a system in which it is being used. The rod and piston of the regulator are constructed, for example, to have a 1/20 ratio such that when the downstream pressure is less than 1/20 of the upstream pressure the regulator opens and when the downstream pressure exceeds 1/20 of the upstream pressure the regulator closes. 10 figs.

  12. Pressure reducing regulator

    DOEpatents

    Whitehead, John C.; Dilgard, Lemoyne W.

    1995-01-01

    A pressure reducing regulator that controls its downstream or outlet pressure to a fixed fraction of its upstream or inlet pressure. The regulator includes a housing which may be of a titanium alloy, within which is located a seal or gasket at the outlet end which may be made of annealed copper, a rod, and piston, each of which may be made of high density graphite. The regulator is insensitive to temperature by virtue of being without a spring or gas sealed behind a diaphragm, and provides a reference for a system in which it is being used. The rod and piston of the regulator are constructed, for example, to have a 1/20 ratio such that when the downstream pressure is less than 1/20 of the upstream pressure the regulator opens and when the downstream pressure exceeds 1/20 of the upstream pressure the regulator closes.

  13. Reduced Order Podolsky Model

    NASA Astrophysics Data System (ADS)

    Thibes, Ronaldo

    2017-02-01

    We perform the canonical and path integral quantizations of a lower-order derivatives model describing Podolsky's generalized electrodynamics. The physical content of the model shows an auxiliary massive vector field coupled to the usual electromagnetic field. The equivalence with Podolsky's original model is studied at classical and quantum levels. Concerning the dynamical time evolution, we obtain a theory with two first-class and two second-class constraints in phase space. We calculate explicitly the corresponding Dirac brackets involving both vector fields. We use the Senjanovic procedure to implement the second-class constraints and the Batalin-Fradkin-Vilkovisky path integral quantization scheme to deal with the symmetries generated by the first-class constraints. The physical interpretation of the results turns out to be simpler due to the reduced derivatives order permeating the equations of motion, Dirac brackets and effective action.

  14. Reducing medical waste.

    PubMed

    Conrardy, Julie; Hillanbrand, Mary; Myers, Sandra; Nussbaum, George F

    2010-06-01

    Medical waste is a necessary by-product of any hospital environment; however, the majority of regulated medical waste is produced in the OR from the use of disposable surgical supplies (eg, drapes, gowns, basins, gloves, sponges). We conducted a concept comparison project in the ORs of two large medical centers in Bethesda, Maryland, and Washington, DC, to evaluate the effects of using reusable surgical basins, gowns, and table and Mayo stand covers in place of disposable products. Survey results indicated that surgeons and surgical technologists found the reusable products to be preferable to the disposable products currently in use. In addition, using reusable products provided a means to decrease regulated medical waste generated in the OR by an average of 65% as well as reduce the cost of waste disposal. AORN recommends evaluating the environmental effects of using reusable, reposable, and disposable products; our findings provide evidence that may be useful to surgical facilities that seek to adopt a "green" approach.

  15. Measuring the reduced shear

    NASA Astrophysics Data System (ADS)

    Zhang, Jun

    2011-11-01

    Neglecting the second order corrections in weak lensing measurements can lead to a few percent uncertainties on cosmic shears, and becomes more important for cluster lensing mass reconstructions. Existing methods which claim to measure the reduced shears are not necessarily accurate to the second order when a point spread function (PSF) is present. We show that the method of Zhang (2008) exactly measures the reduced shears at the second order level in the presence of PSF. A simple theorem is provided for further confirming our calculation, and for judging the accuracy of any shear measurement method at the second order based on its properties at the first order. The method of Zhang (2008) is well defined mathematically. It does not require assumptions on the morphologies of galaxies and the PSF. To reach a sub-percent level accuracy, the CCD pixel size is required to be not larger than 1/3 of the Full Width at Half Maximum (FWHM) of the PSF, regardless of whether the PSF has a power-law or exponential profile at large distances. Using a large ensemble (gtrsim107) of mock galaxies of unrestricted morphologies, we study the shear recovery accuracy under different noise conditions. We find that contaminations to the shear signals from the noise of background photons can be removed in a well defined way because they are not correlated with the source shapes. The residual shear measurement errors due to background noise are consistent with zero at the sub-percent level even when the amplitude of such noise reaches about 1/10 of the source flux within the half-light radius of the source. This limit can in principle be extended further with a larger galaxy ensemble in our simulations. On the other hand, the source Poisson noise remains to be a cause of systematic errors. For a sub-percent level accuracy, our method requires the amplitude of the source Poisson noise to be less than 1/80 ~ 1/100 of the source flux within the half-light radius of the source, corresponding to

  16. Measuring the reduced shear

    SciTech Connect

    Zhang, Jun

    2011-11-01

    Neglecting the second order corrections in weak lensing measurements can lead to a few percent uncertainties on cosmic shears, and becomes more important for cluster lensing mass reconstructions. Existing methods which claim to measure the reduced shears are not necessarily accurate to the second order when a point spread function (PSF) is present. We show that the method of Zhang (2008) exactly measures the reduced shears at the second order level in the presence of PSF. A simple theorem is provided for further confirming our calculation, and for judging the accuracy of any shear measurement method at the second order based on its properties at the first order. The method of Zhang (2008) is well defined mathematically. It does not require assumptions on the morphologies of galaxies and the PSF. To reach a sub-percent level accuracy, the CCD pixel size is required to be not larger than 1/3 of the Full Width at Half Maximum (FWHM) of the PSF, regardless of whether the PSF has a power-law or exponential profile at large distances. Using a large ensemble (∼>10{sup 7}) of mock galaxies of unrestricted morphologies, we study the shear recovery accuracy under different noise conditions. We find that contaminations to the shear signals from the noise of background photons can be removed in a well defined way because they are not correlated with the source shapes. The residual shear measurement errors due to background noise are consistent with zero at the sub-percent level even when the amplitude of such noise reaches about 1/10 of the source flux within the half-light radius of the source. This limit can in principle be extended further with a larger galaxy ensemble in our simulations. On the other hand, the source Poisson noise remains to be a cause of systematic errors. For a sub-percent level accuracy, our method requires the amplitude of the source Poisson noise to be less than 1/80 ∼ 1/100 of the source flux within the half-light radius of the source

  17. Stewarding a Reduced Stockpile

    SciTech Connect

    Goodwin, B T; Mara, G

    2008-04-18

    The future of the US nuclear arsenal continues to be guided by two distinct drivers: the preservation of world peace and the prevention of further proliferation through our extended deterrent umbrella. Timely implementation of US nuclear policy decisions depends, in part, on the current state of stockpile weapons, their delivery systems, and the supporting infrastructure within the Department of Defense (DoD) and the Department of Energy's National Nuclear Security Administration (NNSA). In turn, the present is a product of past choices and world events. Now more than ever, the nuclear weapons program must respond to the changing global security environment and to increasing budget pressures with innovation and sound investments. As the nation transitions to a reduced stockpile, the successes of the Stockpile Stewardship Program (SSP) present options to transition to a sustainable complex better suited to stockpile size, national strategic goals and budgetary realities. Under any stockpile size, we must maintain essential human capital, forefront capabilities, and have a right-sized effective production capacity. We present new concepts for maintaining high confidence at low stockpile numbers and to effectively eliminate the reserve weapons within an optimized complex. We, as a nation, have choices to make on how we will achieve a credible 21st century deterrent.

  18. Reducing miner absenteeism

    SciTech Connect

    Peters, R.H.; Clingan, M.R.; Randolph, R.F.

    1989-01-01

    The U. S. Bureau of Mines has prepared this report on strategies for maintaining high job attendance among underground coal miners because high absenteeism is a threat to miners' safety and seriously hampers productivity. A substantial number of research studies on the effectiveness of various strategies for reducing absenteeism among the employees of nonmining industries have been reported in the literature. These strategies have aimed at improving job attendance through one or more of the following: (1) improving employment procedures, (2) overcoming problems that adversely affect one's ability to attend work, and (3) increasing miners' motivation to attend work. Many of these strategies appear applicable to the mining industry, and are reviewed in the first half of this report. The second half of this report describes how one could develop and implement a program for maintaining high attendance at underground coal mines. The steps include measuring and evaluating attendance levels, formulating attendance goals and an absenteeism policy, developing and implementing an attendance promotion program and periodically going through the preceding steps (known as recycling).

  19. Pollution reducing aircraft propulsion

    SciTech Connect

    Tamura, R.

    1980-07-29

    An aircraft pollution reducing propulsion airfoil system comprising a wing having upper and lower surfaces comprising wing skin plates extending longitudinally on the wing and being spaced one from another in chordwise directions, spars extending into the wing between the surfaces, stringer ducts extending along internal sides of the wing surfaces, the stringers having relatively rigid surface-supporting structure and having outward directed openings extending across the wing surfaces, interrupting the wing surfaces between edges of the wing skin plates, the ducts thereby forming stringer structural elements supporting the wing skin plates, the outward directed openings of the stringer ducts being arranged perpendicularly to the wing surfaces in a leading portion of the wing and tangential to the wing surfaces in a trailing portion of the wing surfaces, suction means connected to the stringer ducts with perpendicular opening for drawing gas into the ducts through those openings and blowing means connected to the ducts with tangential openings for flowing gas out of the tangential openings, combustion means connected to the suction means and to the blowing meanas for accelerating gas through the means.

  20. Reduced Gravity Walking Simulator

    NASA Technical Reports Server (NTRS)

    1963-01-01

    A test subject being suited up for studies on the Reduced Gravity Walking Simulator located in the hanger at Langley Research Center. The initial version of this simulator was located inside the hanger. Later a larger version would be located at the Lunar Landing Facility. The purpose of this simulator was to study the subject while walking, jumping or running. Researchers conducted studies of various factors such as fatigue limit, energy expenditure, and speed of locomotion. Francis B. Smith wrote in his paper 'Simulators For Manned Space Research,' 'I would like to conclude this talk with a discussion of a device for simulating lunar gravity which is very effective and yet which is so simple that its cost is in the order of a few thousand dollars at most, rather than hundreds of thousands. With a little ingenuity, one could almost build this type simulator in his backyard for children to play on. The principle is ...if a test subject is suspended in a sling so that his body axis makes an angle of 9 1/2 degrees with the horizontal and if he then 'stands' on a platform perpendicular to his body axis, the component of the earth's gravity forcing him toward the platform is one times the sine of 9 1/2 degrees or approximately 1/6 of the earth's normal gravity field. That is, a 180 pound astronaut 'standing' on the platform would exert a force of only 30 pounds - the same as if he were standing upright on the lunar surface.' Published in James R. Hansen, Spaceflight Revolution: NASA Langley Research Center From Sputnik to Apollo, NASA SP-4308; Francis B. Smith, 'Simulators For Manned Space Research,' Paper for 1966 IEEE International Convention, New York, NY, March 21-25, 1966.

  1. Reducing gas generators and methods for generating a reducing gas

    DOEpatents

    Scotto, Mark Vincent; Perna, Mark Anthony

    2015-11-03

    One embodiment of the present invention is a unique reducing gas generator. Another embodiment is a unique method for generating a reducing gas. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for generating reducing gas. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.

  2. Gene Variants Reduce Opioid Risks

    MedlinePlus

    ... this reduced potency is due to changes in binding to the receptor or to changes in the ... the body’s natural opioids, β-endorphin. Because this binding reduces the number of receptors required to achieve ...

  3. Oxygen-reducing catalyst layer

    DOEpatents

    O'Brien, Dennis P [Maplewood, MN; Schmoeckel, Alison K [Stillwater, MN; Vernstrom, George D [Cottage Grove, MN; Atanasoski, Radoslav [Edina, MN; Wood, Thomas E [Stillwater, MN; Yang, Ruizhi [Halifax, CA; Easton, E Bradley [Halifax, CA; Dahn, Jeffrey R [Hubley, CA; O'Neill, David G [Lake Elmo, MN

    2011-03-22

    An oxygen-reducing catalyst layer, and a method of making the oxygen-reducing catalyst layer, where the oxygen-reducing catalyst layer includes a catalytic material film disposed on a substrate with the use of physical vapor deposition and thermal treatment. The catalytic material film includes a transition metal that is substantially free of platinum. At least one of the physical vapor deposition and the thermal treatment is performed in a processing environment comprising a nitrogen-containing gas.

  4. Reduced Gravity Zblan Optical Fiber

    NASA Technical Reports Server (NTRS)

    Tucker, Dennis S.; Workman, Gary L.; Smith, Guy A.

    2000-01-01

    Two optical fiber pullers have been designed for pulling ZBLAN optical fiber in reduced gravity. One fiber puller was designed, built and flown on board NASA's KC135 reduced gravity aircraft. A second fiber puller has been designed for use on board the International Space Station.

  5. Reducing crosstalk between stereoscopic views

    NASA Astrophysics Data System (ADS)

    Lipscomb, James S.; Wooten, Wayne L.

    1994-04-01

    Crosstalk between the left and right eyes consists of the one eye's image seen faintly by the other. Image processing can reduce this. The technique is effective, but there are costs of course, and some surprises.

  6. Reducing Cancer Patients' Painful Treatment

    NASA Video Gallery

    A NASA light technology originally developed to aid plant growth experiments in space has proved to reduce the painful side effects resulting from chemotherapy and radiation treatment in bone marro...

  7. Reduced Gravity Education Flight Program

    NASA Video Gallery

    NASA'€™s Reduced Gravity Education Flight Program gives students and educators the opportunity to design, build and fly an experiment in microgravity and get a look at what it takes to be a NASA en...

  8. ISS Update: Reduced Gravity Education

    NASA Video Gallery

    NASA Public Affairs Officer Dan Huot interviews Veronica Seyl, Acting Manager for Reduced Gravity Education. NASA works with students and educators to design experiments for flight testing aboard t...

  9. How to Reduce Solid Waste.

    ERIC Educational Resources Information Center

    Martins, George; Clapp, Leallyn B.

    1974-01-01

    Discusses the problem of solid waste disposal in the United States, suggests ways in which solid wastes might be reduced, and proposes a number of related topics for student debate in classes or in science clubs. (JR)

  10. Learning to REDUCE: A Reduced Electricity Consumption Prediction Ensemble

    SciTech Connect

    Aman, Saima; Chelmis, Charalampos; Prasanna, Viktor

    2016-02-12

    Utilities use Demand Response (DR) to balance supply and demand in the electric grid by involving customers in efforts to reduce electricity consumption during peak periods. To implement and adapt DR under dynamically changing conditions of the grid, reliable prediction of reduced consumption is critical. However, despite the wealth of research on electricity consumption prediction and DR being long in practice, the problem of reduced consumption prediction remains largely un-addressed. In this paper, we identify unique computational challenges associated with the prediction of reduced consumption and contrast this to that of normal consumption and DR baseline prediction.We propose a novel ensemble model that leverages different sequences of daily electricity consumption on DR event days as well as contextual attributes for reduced consumption prediction. We demonstrate the success of our model on a large, real-world, high resolution dataset from a university microgrid comprising of over 950 DR events across a diverse set of 32 buildings. Our model achieves an average error of 13.5%, an 8.8% improvement over the baseline. Our work is particularly relevant for buildings where electricity consumption is not tied to strict schedules. Our results and insights should prove useful to the researchers and practitioners working in the sustainable energy domain.

  11. Determining Reduced Order Models for Optimal Stochastic Reduced Order Models

    SciTech Connect

    Bonney, Matthew S.; Brake, Matthew R.W.

    2015-08-01

    The use of parameterized reduced order models(PROMs) within the stochastic reduced order model (SROM) framework is a logical progression for both methods. In this report, five different parameterized reduced order models are selected and critiqued against the other models along with truth model for the example of the Brake-Reuss beam. The models are: a Taylor series using finite difference, a proper orthogonal decomposition of the the output, a Craig-Bampton representation of the model, a method that uses Hyper-Dual numbers to determine the sensitivities, and a Meta-Model method that uses the Hyper-Dual results and constructs a polynomial curve to better represent the output data. The methods are compared against a parameter sweep and a distribution propagation where the first four statistical moments are used as a comparison. Each method produces very accurate results with the Craig-Bampton reduction having the least accurate results. The models are also compared based on time requirements for the evaluation of each model where the Meta- Model requires the least amount of time for computation by a significant amount. Each of the five models provided accurate results in a reasonable time frame. The determination of which model to use is dependent on the availability of the high-fidelity model and how many evaluations can be performed. Analysis of the output distribution is examined by using a large Monte-Carlo simulation along with a reduced simulation using Latin Hypercube and the stochastic reduced order model sampling technique. Both techniques produced accurate results. The stochastic reduced order modeling technique produced less error when compared to an exhaustive sampling for the majority of methods.

  12. Strategies to Reduce Indoor Tanning

    PubMed Central

    Holman, Dawn M.; Fox, Kathleen A.; Glenn, Jeffrey D.; Guy, Gery P.; Watson, Meg; Baker, Katie; Cokkinides, Vilma; Gottlieb, Mark; Lazovich, DeAnn; Perna, Frank M.; Sampson, Blake P.; Seidenberg, Andrew B.; Sinclair, Craig; Geller, Alan C.

    2015-01-01

    Exposure to ultraviolet radiation from indoor tanning device use is associated with an increased risk of skin cancer, including risk of malignant melanoma, and is an urgent public health problem. By reducing indoor tanning, future cases of skin cancer could be prevented, along with the associated morbidity, mortality, and healthcare costs. On August 20, 2012, the CDC hosted a meeting to discuss the current body of evidence on strategies to reduce indoor tanning as well as research gaps. Using the Action Model to Achieve Healthy People 2020 Overarching Goals as a framework, the current paper provides highlights on the topics that were discussed, including (1) the state of the evidence on strategies to reduce indoor tanning; (2) the tools necessary to effectively assess, monitor, and evaluate the short- and long-term impact of interventions designed to reduce indoor tanning; and (3) strategies to align efforts at the national, state, and local levels through transdisciplinary collaboration and coordination across multiple sectors. Although many challenges and barriers exist, a coordinated, multilevel, transdisciplinary approach has the potential to reduce indoor tanning and prevent future cases of skin cancer. PMID:23683986

  13. Sleep can reduce proactive interference.

    PubMed

    Abel, Magdalena; Bäuml, Karl-Heinz T

    2014-01-01

    Sleep has repeatedly been connected to processes of memory consolidation. While extensive research indeed documents beneficial effects of sleep on memory, little is yet known about the role of sleep for interference effects in episodic memory. Although two prior studies reported sleep to reduce retroactive interference, no sleep effect has previously been found for proactive interference. Here we applied a study format differing from that employed by the prior studies to induce a high degree of proactive interference, and asked participants to encode a single list or two interfering lists of paired associates via pure study cycles. Testing occurred after 12 hours of diurnal wakefulness or nocturnal sleep. Consistent with the prior work, we found sleep in comparison to wake did not affect memory for the single list, but reduced retroactive interference. In addition we found sleep reduced proactive interference, and reduced retroactive and proactive interference to the same extent. The finding is consistent with the view that arising benefits of sleep are caused by the reactivation of memory contents during sleep, which has been suggested to strengthen and stabilise memories. Such stabilisation may make memories less susceptible to competition from interfering memories at test and thus reduce interference effects.

  14. Reduce air, reduce compliance cost new patented spray booth technology

    SciTech Connect

    McGinnis, F.

    1997-12-31

    A New Paint Spray Booth System that dramatically reduces air volumes normally required for capturing and controlling paint overspray that contains either Volatile Organic Compounds (VOC) or Hazardous Air Pollutants (HAP), or both. In turn, a substantial reduction in capital equipment expenditures for air abatement systems and air make-up heaters as well as related annual operating expenses is realized.

  15. Power and reduced temporal discounting.

    PubMed

    Joshi, Priyanka D; Fast, Nathanael J

    2013-04-01

    Decision makers generally feel disconnected from their future selves, an experience that leads them to prefer smaller immediate gains to larger future gains. This pervasive tendency is known as temporal discounting, and researchers across disciplines are interested in understanding how to overcome it. Following recent advances in the power literature, we suggest that the experience of power enhances one's connection with the future self, which in turn results in reduced temporal discounting. In Study 1, we found that participants assigned to high-power roles were less likely than participants assigned to low-power roles to display temporal discounting. In Studies 2 and 3, priming power reduced temporal discounting in monetary and nonmonetary tasks, and, further, connection with the future self mediated the relation between power and reduced discounting. In Study 4, experiencing a general sense of power in the workplace predicted actual lifetime savings. These results have important implications for future research.

  16. Microbial methods of reducing technetium

    DOEpatents

    Wildung, Raymond E [Richland, WA; Garland, Thomas R [Greybull, WY; Gorby, Yuri A [Richland, WA; Hess, Nancy J [Benton City, WA; Li, Shu-Mei W [Richland, WA; Plymale, Andrew E [Richland, WA

    2001-01-01

    The present invention is directed toward a method for microbial reduction of a technetium compound to form other compounds of value in medical imaging. The technetium compound is combined in a mixture with non-growing microbial cells which contain a technetium-reducing enzyme system, a stabilizing agent and an electron donor in a saline solution under anaerobic conditions. The mixture is substantially free of an inorganic technetium reducing agent and its reduction products. The resulting product is Tc of lower oxidation states, the form of which can be partially controlled by the stabilizing agent. It has been discovered that the microorganisms Shewanella alga, strain Bry and Shewanelia putrifacians, strain CN-32 contain the necessary enzyme systems for technetium reduction and can form both mono nuclear and polynuclear reduced Tc species depending on the stabilizing agent.

  17. Contrasting reduced overshadowing and blocking.

    PubMed

    Wheeler, Daniel S; Miller, Ralph R

    2007-07-01

    Preexposure of a cue without an outcome (X-) prior to compound pairings with the outcome (XZ-->O) can reduce overshadowing of a target cue (Z). Moreover, pairing a cue with an outcome (X-->O) before compound training can enhance its ability to compete with another cue (i.e., blocking). Four experiments were conducted in a conditioned bar-press suppression preparation with rats to determine whether spacing of the X- or X-->O trials would differentially affect reduced overshadowing and blocking. Experiment 1a showed that reduced overshadowing was larger with massed trials than with spaced trials. Experiment 1b found that blocking was larger with spaced trials than with massed trials. Experiments 2a and 2b indicated that these effects of trial spacing were both mediated by the associative status of the context at test. The results are interpreted in the framework of contemporary learning theories.

  18. Six ways to reduce inventory.

    PubMed

    Lunn, T

    1996-05-01

    The purpose of this presentation is to help you reduce the inventory in your operation. We will accomplish that task by discussing six specific methods that companies have used successfully to reduce their inventory. One common attribute of these successes is that they also build teamwork among the people. Every business operation today is concerned with methods to improve customer service. The real trick is to accomplish that task without increasing inventory. We are all concerned with improving our skills at keeping inventory low.

  19. Flexure Bearing Reduces Startup Friction

    NASA Technical Reports Server (NTRS)

    Clingman, W. Dean

    1991-01-01

    Design concept for ball bearing incorporates small pieces of shim stock, wire spokes like those in bicycle wheels, or other flexing elements to reduce both stiction and friction slope. In flexure bearing, flexing elements placed between outer race of ball bearing and outer ring. Elements flex when ball bearings encounter small frictional-torque "bumps" or even larger ones when bearing balls encounter buildups of grease on inner or outer race. Flexure of elements reduce high friction slopes of "bumps", helping to keep torque between outer ring and inner race low and more nearly constant. Concept intended for bearings in gimbals on laser and/or antenna mirrors.

  20. Grape seed polyphenols and curcumin reduce genomic instability events in a transgenic mouse model for Alzheimer's disease.

    PubMed

    Thomas, Philip; Wang, Yan-Jiang; Zhong, Jin-Hua; Kosaraju, Shantha; O'Callaghan, Nathan J; Zhou, Xin-Fu; Fenech, Michael

    2009-02-10

    The study set out to determine (a) whether DNA damage is elevated in mice that carry mutations in the amyloid precursor protein (APP695swe) and presenilin 1 (PSEN1-dE9) that predispose to Alzheimer's disease (AD) relative to non-transgenic control mice, and (b) whether increasing the intake of dietary polyphenols from curcumin or grape seed extract could reduce genomic instability events in a transgenic mouse model for AD. DNA damage was measured using the micronucleus (MN) assay in both buccal mucosa and erythrocytes and an absolute telomere length assay for both buccal mucosa and olfactory bulb tissue. MN frequency tended to be higher in AD mice in both buccal mucosa (1.7-fold) and polychromatic erythrocytes (1.3-fold) relative to controls. Telomere length was significantly reduced by 91% (p=0.04) and non-significantly reduced by 50% in buccal mucosa and olfactory bulbs respectively in AD mice relative to controls. A significant 10-fold decrease in buccal MN frequency (p=0.01) was found for AD mice fed diets containing curcumin (CUR) or micro-encapsulated grape seed extract (MGSE) and a 7-fold decrease (p=0.02) for AD mice fed unencapsulated grape seed extract (GSE) compared to the AD group on control diet. Similarly, in polychromatic erythrocytes a significant reduction in MN frequency was found for the MGSE cohort (65.3%) (p<0.05), whereas the AD CUR and AD GSE groups were non-significantly reduced by 39.2 and 34.8% respectively compared to the AD Control. A non-significant 2-fold increase in buccal cell telomere length was evident for the CUR, GSE and MGSE groups compared to the AD control group. Olfactory bulb telomere length was found to be non-significantly 2-fold longer in mice fed on the CUR diet compared to controls. These results suggest potential protective effects of polyphenols against genomic instability events in different somatic tissues of a transgenic mouse model for AD.

  1. Reducing Life-Cycle Costs.

    ERIC Educational Resources Information Center

    Roodvoets, David L.

    2003-01-01

    Presents factors to consider when determining roofing life-cycle costs, explaining that costs do not tell the whole story; discussing components that should go into the decision (cost, maintenance, energy use, and environmental costs); and concluding that important elements in reducing life-cycle costs include energy savings through increased…

  2. METHOD OF REDUCING PLUTONIUM COMPOUNDS

    DOEpatents

    Johns, I.B.

    1958-06-01

    A method is described for reducing plutonium compounds in aqueous solution from a higher to a lower valence state. This reduction of valence is achieved by treating the aqueous solution of higher valence plutonium compounds with hydrogen in contact with an activated platinum catalyst.

  3. Reduced False Memory after Sleep

    ERIC Educational Resources Information Center

    Fenn, Kimberly M.; Gallo, David A.; Margoliash, Daniel; Roediger, Henry L., III; Nusbaum, Howard C.

    2009-01-01

    Several studies have shown that sleep contributes to the successful maintenance of previously encoded information. This research has focused exclusively on memory for studied events, as opposed to false memories. Here we report three experiments showing that sleep reduces false memories in the Deese-Roediger-McDermott (DRM) memory illusion. False…

  4. Reducing Crime by Eliminating Cash.

    ERIC Educational Resources Information Center

    Warwick, David R.

    Ending the use of cash in the United States can provide substantial social and economic gain while requiring only modest levels of investment. One primary benefit is the reduction of cash-related crimes. Because most street crime is committed to obtain cash or uses cash as a transaction medium, elimination of cash will dramatically reduce crime.…

  5. Reduce Waste for Greener Holidays

    EPA Pesticide Factsheets

    DALLAS - (Dec. 15, 2015) Friends, family, parties, and travel are what make the holiday season great. You can make it even better by reducing waste as often as possible during your celebrations. The U.S. Environmental Protection Agency (EPA) wants t

  6. Reference Works in Reduced Size

    ERIC Educational Resources Information Center

    Hennessey, David

    1977-01-01

    Lower cost and less shelf space requirements have made major reference works in miniaturized print editions attractive to small libraries. The major disadvantage is the necessity of a magnifying glass for reading entries. A bibliography of reduced-size editions is included. (JAB)

  7. Reducing cement's CO2 footprint

    USGS Publications Warehouse

    van Oss, Hendrik G.

    2011-01-01

    The manufacturing process for Portland cement causes high levels of greenhouse gas emissions. However, environmental impacts can be reduced by using more energy-efficient kilns and replacing fossil energy with alternative fuels. Although carbon capture and new cements with less CO2 emission are still in the experimental phase, all these innovations can help develop a cleaner cement industry.

  8. Hindlimb suspension reduces muscle regeneration

    NASA Technical Reports Server (NTRS)

    Mozdziak, P. E.; Truong, Q.; Macius, A.; Schultz, E.

    1998-01-01

    Exposure of juvenile skeletal muscle to a weightless environment reduces growth and satellite cell mitotic activity. However, the effect of a weightless environment on the satellite cell population during muscle repair remains unknown. Muscle injury was induced in rat soleus muscles using the myotoxic snake venom, notexin. Rats were placed into hindlimb-suspended or weightbearing groups for 10 days following injury. Cellular proliferation during regeneration was evaluated using 5-bromo-2'-deoxyuridine (BrdU) immunohistochemistry and image analysis. Hindlimb suspension reduced (P < 0.05) regenerated muscle mass, regenerated myofiber diameter, uninjured muscle mass, and uninjured myofiber diameter compared to weightbearing rats. Hindlimb suspension reduced (P < 0.05) BrdU labeling in uninjured soleus muscles compared to weight-bearing muscles. However, hindlimb suspension did not abolish muscle regeneration because myofibers formed in the injured soleus muscles of hindlimb-suspended rats, and BrdU labeling was equivalent (P > 0.10) on myofiber segments isolated from the soleus muscles of hindlimb-suspended and weightbearing rats following injury. Thus, hindlimb suspension (weightlessness) does not suppress satellite cell mitotic activity in regenerating muscles before myofiber formation, but reduces growth of the newly formed myofibers.

  9. Reducing Poverty through Preschool Interventions

    ERIC Educational Resources Information Center

    Duncan, Greg J.; Ludwig, Jens; Magnuson, Katherine A.

    2007-01-01

    Greg Duncan, Jens Ludwig, and Katherine Magnuson explain how providing high-quality care to disadvantaged preschool children can help reduce poverty. In early childhood, they note, children's cognitive and socioemotional skills develop rapidly and are sensitive to "inputs" from parents, home learning environments, child care settings, and the…

  10. Do Rewards Reduce Student Motivation?

    ERIC Educational Resources Information Center

    Malouf, David

    1983-01-01

    The reduced continuing motivation effect is examined with regard to research, theory, and implications for practice. The description of research focuses primarily on studies conducted with preschool-aged or school-aged subjects. Explanations based on self-perception or attributional theory and learning theory are examined. (Author/PN)

  11. Reduced-vibration tube array

    DOEpatents

    Bruck, Gerald J.; Bartolomeo, Daniel R.

    2004-07-20

    A reduced-vibration tube array is disclosed. The array includes a plurality of tubes in a fixed arrangement and a plurality of damping members positioned within the tubes. The damping members include contoured interface regions characterized by bracing points that selectively contact the inner surface of an associated tube. Each interface region is sized and shaped in accordance with the associated tube, so that the damping member bracing points are spaced apart a vibration-reducing distance from the associated tube inner surfaces at equilibrium. During operation, mechanical interaction between the bracing points and the tube inner surfaces reduces vibration by a damage-reducing degree. In one embodiment, the interface regions are serpentine shaped. In another embodiment, the interface regions are helical in shape. The interface regions may be simultaneously helical and serpentine in shape. The damping members may be fixed within the associated tubes, and damping member may be customized several interference regions having attributes chosen in accordance with desired flow characteristics and associated tube properties.

  12. Pressure Reducer for Coal Gasifiers

    NASA Technical Reports Server (NTRS)

    Kendall, James M., Sr.

    1983-01-01

    Quasi-porous-plug pressure reducer is designed for gases containing abrasive particles. Gas used to generate high pressure steam to drive electric power generators. In giving up heat to steam, gas drops in temperature. Device used for coal gasification plants.

  13. Distinguishing iron-reducing from sulfate-reducing conditions

    USGS Publications Warehouse

    Chapelle, F.H.; Bradley, P.M.; Thomas, M.A.; McMahon, P.B.

    2009-01-01

    Ground water systems dominated by iron- or sulfate-reducing conditions may be distinguished by observing concentrations of dissolved iron (Fe2+) and sulfide (sum of H2S, HS-, and S= species and denoted here as "H2S"). This approach is based on the observation that concentrations of Fe2+ and H2S in ground water systems tend to be inversely related according to a hyperbolic function. That is, when Fe2+ concentrations are high, H2S concentrations tend to be low and vice versa. This relation partly reflects the rapid reaction kinetics of Fe2+ with H2S to produce relatively insoluble ferrous sulfides (FeS). This relation also reflects competition for organic substrates between the iron- and the sulfate-reducing microorganisms that catalyze the production of Fe2+ and H 2S. These solubility and microbial constraints operate in tandem, resulting in the observed hyperbolic relation between Fe2+ and H 2S concentrations. Concentrations of redox indicators, including dissolved hydrogen (H2) measured in a shallow aquifer in Hanahan, South Carolina, suggest that if the Fe2+/H2S mass ratio (units of mg/L) exceeded 10, the screened interval being tapped was consistently iron reducing (H2 ???0.2 to 0.8 nM). Conversely, if the Fe 2+/H2S ratio was less than 0.30, consistent sulfate-reducing (H2 ???1 to 5 nM) conditions were observed over time. Concomitantly high Fe2+ and H2S concentrations were associated with H2 concentrations that varied between 0.2 and 5.0 nM over time, suggesting mixing of water from adjacent iron- and sulfate-reducing zones or concomitant iron and sulfate reduction under nonelectron donor-limited conditions. These observations suggest that Fe2+/H2S mass ratios may provide useful information concerning the occurrence and distribution of iron and sulfate reduction in ground water systems. ?? 2009 National Ground Water Association.

  14. Structural reducibility of multilayer networks

    NASA Astrophysics Data System (ADS)

    de Domenico, Manlio; Nicosia, Vincenzo; Arenas, Alexandre; Latora, Vito

    2015-04-01

    Many complex systems can be represented as networks consisting of distinct types of interactions, which can be categorized as links belonging to different layers. For example, a good description of the full protein-protein interactome requires, for some organisms, up to seven distinct network layers, accounting for different genetic and physical interactions, each containing thousands of protein-protein relationships. A fundamental open question is then how many layers are indeed necessary to accurately represent the structure of a multilayered complex system. Here we introduce a method based on quantum theory to reduce the number of layers to a minimum while maximizing the distinguishability between the multilayer network and the corresponding aggregated graph. We validate our approach on synthetic benchmarks and we show that the number of informative layers in some real multilayer networks of protein-genetic interactions, social, economical and transportation systems can be reduced by up to 75%.

  15. Alcohol reduces aversion to ambiguity.

    PubMed

    Tyszka, Tadeusz; Macko, Anna; Stańczak, Maciej

    2014-01-01

    Several years ago, Cohen et al. (1958) demonstrated that under the influence of alcohol drivers became more risk prone, although their risk perception remained unchanged. Research shows that ambiguity aversion is to some extent positively correlated with risk aversion, though not very highly (Camerer and Weber, 1992). The question addressed by the present research is whether alcohol reduces ambiguity aversion. Our research was conducted in a natural setting (a restaurant bar), where customers with differing levels of alcohol intoxication were offered a choice between a risky and an ambiguous lottery. We found that alcohol reduced ambiguity aversion and that the effect occurred in men but not women. We interpret these findings in terms of the risk-as-value hypothesis, according to which, people in Western culture tend to value risk, and suggest that alcohol consumption triggers adherence to socially and culturally valued patterns of conduct different for men and women.

  16. Contrails reduce daily temperature range.

    PubMed

    Travis, David J; Carleton, Andrew M; Lauritsen, Ryan G

    2002-08-08

    The potential of condensation trails (contrails) from jet aircraft to affect regional-scale surface temperatures has been debated for years, but was difficult to verify until an opportunity arose as a result of the three-day grounding of all commercial aircraft in the United States in the aftermath of the terrorist attacks on 11 September 2001. Here we show that there was an anomalous increase in the average diurnal temperature range (that is, the difference between the daytime maximum and night-time minimum temperatures) for the period 11-14 September 2001. Because persisting contrails can reduce the transfer of both incoming solar and outgoing infrared radiation and so reduce the daily temperature range, we attribute at least a portion of this anomaly to the absence of contrails over this period.

  17. Reducing carbon dioxide to products

    SciTech Connect

    Cole, Emily Barton; Sivasankar, Narayanappa; Parajuli, Rishi; Keets, Kate A

    2014-09-30

    A method reducing carbon dioxide to one or more products may include steps (A) to (C). Step (A) may bubble said carbon dioxide into a solution of an electrolyte and a catalyst in a divided electrochemical cell. The divided electrochemical cell may include an anode in a first cell compartment and a cathode in a second cell compartment. The cathode may reduce said carbon dioxide into said products. Step (B) may adjust one or more of (a) a cathode material, (b) a surface morphology of said cathode, (c) said electrolyte, (d) a manner in which said carbon dioxide is bubbled, (e), a pH level of said solution, and (f) an electrical potential of said divided electrochemical cell, to vary at least one of (i) which of said products is produced and (ii) a faradaic yield of said products. Step (C) may separate said products from said solution.

  18. Mindfulness reduces the correspondence bias.

    PubMed

    Hopthrow, Tim; Hooper, Nic; Mahmood, Lynsey; Meier, Brian P; Weger, Ulrich

    2017-03-01

    The correspondence bias (CB) refers to the idea that people sometimes give undue weight to dispositional rather than situational factors when explaining behaviours and attitudes. Three experiments examined whether mindfulness, a non-judgmental focus on the present moment, could reduce the CB. Participants engaged in a brief mindfulness exercise (the raisin task), a control task, or an attention to detail task before completing a typical CB measure involving an attitude-attribution paradigm. The results indicated that participants in the mindfulness condition experienced a significant reduction in the CB compared to participants in the control or attention to detail conditions. These results suggest that mindfulness training can play a unique role in reducing social biases related to person perception.

  19. Alcohol reduces aversion to ambiguity

    PubMed Central

    Tyszka, Tadeusz; Macko, Anna; Stańczak, Maciej

    2015-01-01

    Several years ago, Cohen et al. (1958) demonstrated that under the influence of alcohol drivers became more risk prone, although their risk perception remained unchanged. Research shows that ambiguity aversion is to some extent positively correlated with risk aversion, though not very highly (Camerer and Weber, 1992). The question addressed by the present research is whether alcohol reduces ambiguity aversion. Our research was conducted in a natural setting (a restaurant bar), where customers with differing levels of alcohol intoxication were offered a choice between a risky and an ambiguous lottery. We found that alcohol reduced ambiguity aversion and that the effect occurred in men but not women. We interpret these findings in terms of the risk-as-value hypothesis, according to which, people in Western culture tend to value risk, and suggest that alcohol consumption triggers adherence to socially and culturally valued patterns of conduct different for men and women. PMID:25642202

  20. Correlated Electrons in Reduced Dimensions

    SciTech Connect

    Bonesteel, Nicholas E

    2015-01-31

    This report summarizes the work accomplished under the support of US DOE grant # DE-FG02-97ER45639, "Correlated Electrons in Reduced Dimensions." The underlying hypothesis of the research supported by this grant has been that studying the unique behavior of correlated electrons in reduced dimensions can lead to new ways of understanding how matter can order and how it can potentially be used. The systems under study have included i) fractional quantum Hall matter, which is realized when electrons are confined to two-dimensions and placed in a strong magnetic field at low temperature, ii) one-dimensional chains of spins and exotic quasiparticle excitations of topologically ordered matter, and iii) electrons confined in effectively ``zero-dimensional" semiconductor quantum dots.

  1. Ferroelectric capacitor with reduced imprint

    DOEpatents

    Evans, Jr., Joseph T.; Warren, William L.; Tuttle, Bruce A.; Dimos, Duane B.; Pike, Gordon E.

    1997-01-01

    An improved ferroelectric capacitor exhibiting reduced imprint effects in comparison to prior art capacitors. A capacitor according to the present invention includes top and bottom electrodes and a ferroelectric layer sandwiched between the top and bottom electrodes, the ferroelectric layer comprising a perovskite structure of the chemical composition ABO.sub.3 wherein the B-site comprises first and second elements and a dopant element that has an oxidation state greater than +4. The concentration of the dopant is sufficient to reduce shifts in the coercive voltage of the capacitor with time. In the preferred embodiment of the present invention, the ferroelectric element comprises Pb in the A-site, and the first and second elements are Zr and Ti, respectively. The preferred dopant is chosen from the group consisting of Niobium, Tantalum, and Tungsten. In the preferred embodiment of the present invention, the dopant occupies between 1 and 8% of the B-sites.

  2. Tandem motors reduce well costs

    SciTech Connect

    Hooper, M.; Daigle, C.; Crowe, R.

    1995-10-01

    The new generation of tandem mud motors that recently appeared on the drilling scene is significantly affecting drilling efficiency worldwide. These motors provide drillers with increased horsepower at the bit, higher torque, and faster rates of penetration (ROP). With advanced engineering and more durable materials, motor life is being extended, thereby increasing the time between bit trips and reducing drilling costs. This article reviews the performance, design, and operation of these motors.

  3. MapReduce SVM Game

    SciTech Connect

    Vineyard, Craig M.; Verzi, Stephen J.; James, Conrad D.; Aimone, James B.; Heileman, Gregory L.

    2015-08-10

    Despite technological advances making computing devices faster, smaller, and more prevalent in today's age, data generation and collection has outpaced data processing capabilities. Simply having more compute platforms does not provide a means of addressing challenging problems in the big data era. Rather, alternative processing approaches are needed and the application of machine learning to big data is hugely important. The MapReduce programming paradigm is an alternative to conventional supercomputing approaches, and requires less stringent data passing constrained problem decompositions. Rather, MapReduce relies upon defining a means of partitioning the desired problem so that subsets may be computed independently and recom- bined to yield the net desired result. However, not all machine learning algorithms are amenable to such an approach. Game-theoretic algorithms are often innately distributed, consisting of local interactions between players without requiring a central authority and are iterative by nature rather than requiring extensive retraining. Effectively, a game-theoretic approach to machine learning is well suited for the MapReduce paradigm and provides a novel, alternative new perspective to addressing the big data problem. In this paper we present a variant of our Support Vector Machine (SVM) Game classifier which may be used in a distributed manner, and show an illustrative example of applying this algorithm.

  4. MapReduce SVM Game

    DOE PAGES

    Vineyard, Craig M.; Verzi, Stephen J.; James, Conrad D.; ...

    2015-08-10

    Despite technological advances making computing devices faster, smaller, and more prevalent in today's age, data generation and collection has outpaced data processing capabilities. Simply having more compute platforms does not provide a means of addressing challenging problems in the big data era. Rather, alternative processing approaches are needed and the application of machine learning to big data is hugely important. The MapReduce programming paradigm is an alternative to conventional supercomputing approaches, and requires less stringent data passing constrained problem decompositions. Rather, MapReduce relies upon defining a means of partitioning the desired problem so that subsets may be computed independently andmore » recom- bined to yield the net desired result. However, not all machine learning algorithms are amenable to such an approach. Game-theoretic algorithms are often innately distributed, consisting of local interactions between players without requiring a central authority and are iterative by nature rather than requiring extensive retraining. Effectively, a game-theoretic approach to machine learning is well suited for the MapReduce paradigm and provides a novel, alternative new perspective to addressing the big data problem. In this paper we present a variant of our Support Vector Machine (SVM) Game classifier which may be used in a distributed manner, and show an illustrative example of applying this algorithm.« less

  5. The usefulness of a continuous administration of tirapazamine combined with reduced dose-rate irradiation using {gamma}-rays or reactor thermal neutrons.

    PubMed

    Masunaga, S; Sakurai, Y; Nagata, K; Suzuki, M; Maruhashi, A; Kinashi, Y; Nagasawa, H; Uto, Y; Hori, H; Ono, K

    2006-12-01

    We clarified the usefulness of the continuous administration of tirapazamine (TPZ) in combination with reduced dose-rate irradiation (RDRI) using gamma-rays or reactor thermal neutrons. Squamous cell carcinoma (SCC) VII tumour-bearing mice received a continuous administration of 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating (P) cells. Then, they received a single intraperitoneal injection or 24 h continuous subcutaneous infusion of TPZ in combination with conventional dose-rate irradiation (CDRI) or RDRI using gamma-rays or thermal neutrons. After irradiation, the tumour cells were isolated and incubated with a cytokinesis blocker, and the micronucleus (MN) frequency in cells without BrdU labelling ( = quiescent (Q) cells) was determined using immunofluorescence staining for BrdU. The MN frequency in the total tumour cells was determined using tumours that were not pre-treated with BrdU. The sensitivity of both total and Q cells, especially of Q cells, was significantly reduced with RDRI compared with CDRI. Combination of TPZ increased the sensitivity of both populations, with a slightly more remarkable increase in Q cells. Furthermore, the continuous administration of TPZ raised the sensitivity of both total and Q cell populations, especially the former, more markedly than the single administration, whether combined with CDRI or RDRI using gamma-rays or thermal neutrons. From the viewpoint of solid tumour control as a whole, including intratumour Q-cell control, the use of TPZ, especially when administered continuously, combined with RDRI, is useful for suppressing the reduction in the sensitivity of tumour cells caused by the decrease in irradiation dose rate in vivo.

  6. In vitro mutagenicity and genotoxicity study of a number of short-chain chlorinated hydrocarbons using the micronucleus test and the alkaline single cell gel electrophoresis technique (Comet assay) in human lymphocytes: a structure-activity relationship (QSAR) analysis of the genotoxic and cytotoxic potential.

    PubMed

    Tafazoli, M; Baeten, A; Geerlings, P; Kirsch-Volders, M

    1998-03-01

    Using the micronucleus (MN) test and the alkaline single cell gel electrophoresis (Comet) assay, potential mutagenicity (MN formation), genotoxicity (DNA breakage capacity) and cytotoxicity (cell proliferation reduction) of five chlorinated hydrocarbons (carbon tetrachloride, hexachloroethane, 1,2-dichloroethane, 1-chlorohexane and 2,3-dichlorobutane) have been evaluated in isolated human lymphocytes. With the MN test a low but statistically significant mutagenic activity was detected for all tested substances (except 2,3-dichlorobutane) with one out of the two donors and in the presence or absence of an exogenous metabolic activation system (S9 mix). However, at the concentration ranges tested none of the positive compounds induced a clear dose-dependent mutagenic effect. The Comet assay detected a strong DNA damaging effect for 1-chlorohexane, 2,3-dichlorobutane and 1,2-dichloroethane, but not for carbon tetrachloride and hexachloroethane. The influence of metabolism on the genotoxic activity of the chemicals was more clear in the Comet assay than in the MN test. The experimental genotoxicity and cytotoxicity data obtained in this study, together with data on five more related chemicals previously investigated, and their physico-chemical descriptors or electronic parameters have been used for QSAR analysis. The QSAR analysis high-lighted that the toxicity of the tested compounds was influenced by different parameters, like lipophilicity (logP), electron donor ability (charge) and longest carbon-chlorine (LBC-Cl) bond length. In addition, steric parameters, like molar refractivity (MR) and LBC-Cl, and electronic parameters, like ELUMO (energy of the lowest unoccupied molecular orbital, indicating electrophilicity), were predominant factors discriminating genotoxins from non-genotoxins in the presence but not in the absence of S9 mix. Although a limited number of compounds have been examined and cytotoxicity and genotoxicity were identified in two different

  7. Assessing of genotoxicity of 16 centralized source-waters in China by means of the SOS/umu assay and the micronucleus test: initial identification of the potential genotoxicants by use of a GC/MS method and the QSAR Toolbox 3.0.

    PubMed

    Ye, Yan; Weiwei, Jiang; Na, Li; Mei, Ma; Donghong, Wang; Zijian, Wang; Kaifeng, Rao

    2014-03-15

    Only few studies were conducted to assess genotoxicity of centralized source waters in China and almost none of them dealt with the causal relationship between the genotoxic effect and genotoxicants. In this work, 16 centralized source waters in China were sampled from five river systems and genotoxicity of their organic extracts was assessed by use of the SOS/umu test for DNA-damaging effect and the miniaturized flow cytometry-based micronucleus (MN) test for chromosome-damaging effect. In addition, initial identification of potential genotoxicants for the six samples from the Yangtze River was done with a GC/MS method and the QSAR toolbox 3.0. The results demonstrate that eight samples showed both indirect and direct DNA-damaging effects, another four samples showed only indirect DNA-damaging effects, while chromosome-damaging effects were found for 14 out of the 16 samples, in which aneugenic and clastogenic modes of action were found for 4 and 10 samples, respectively. Both direct/indirect DNA-damaging effects and chromosome-damaging effects were induced by the six Yangtze River samples, and the existing different types of genotoxicant confirmed the results. Furthermore, o-phenylphenol was initially identified as the major cause for the DNA-damaging effects while PAHs, pesticides, phenol and anthraquinone were identified as ubiquitous chromosome-damaging agents among these samples. In conclusion, a combination of the SOS/umu test and the miniaturized flow cytometry-based MN test to detect both DNA-damaging and chromosome-damaging effects could be used as a comprehensive genotoxicity assessment tool for the evaluation and classification of genotoxicity of complex mixtures, and potential genotoxicants can be initially identified with additional information from chemical analysis and the QSAR toolbox.

  8. Interventions to Reduce Sedentary Behavior

    PubMed Central

    Manini, Todd M.; Carr, Lucas J.; King, Abby C.; Marshall, Simon; Robinson, Thomas N.; Rejeski, W. Jack

    2014-01-01

    Purpose This paper reports on presentations and discussion from the working group on “Influences on Sedentary Behavior & Interventions” as part of the Sedentary Behavior: Identifying Research Priorities Workshop. Methods Interventions were discussed in the context of targeting sedentary behavior (SB) as a concept distinct from physical activity (PA). It was recommended that interventions targeting SB should consider a life course perspective, a position predicated on the assumption that SB is age and life stage dependent. Additionally, targeting environments where individuals have high exposure to SB— such as workplace sitting— could benefit from new technology (e.g., computer-based prompting to stand or move), environmental changes (e.g., active workstations), policies targeting reduced sedentary time (e.g., allowing employees regular desk breaks), or by changing norms surrounding prolonged sitting (e.g., standing meetings). Results & Conclusions There are limited data about the minimal amount of SB change required to produce meaningful health benefits. In addition to developing relevant scientific and public health definitions of SB, it is important to further delineate the scope of health and quality of life outcomes associated with reduced SB across the life course, and clarify what behavioral alternatives to SB can be used to optimize health gains. SB interventions will benefit from having more clarity about the potential physiological and behavioral synergies with current PA recommendations, developing multi-level interventions aimed at reducing SB across all life phases and contexts, harnessing relevant and effective strategies to extend the reach of interventions to all sectors of society, as well as applying state-of-the-science adaptive designs and methods to accelerate advances in the science of sedentary behavior interventions. PMID:25222818

  9. Empowerment to reduce health disparities.

    PubMed

    Wallerstein, Nina

    2002-01-01

    This article articulates the theoretical construct of empowerment and its importance for health-enhancing strategies to reduce health disparities. Powerlessness is explored as a risk factor in the context of social determinants, such as poverty, discrimination, workplace hazards, and income inequities. Empowerment is presented and compared with social capital and community capacity as strategies to strengthen social protective factors. A case study of a youth empowerment and policy project in New Mexico illustrates the usefulness of empowerment strategies in both targeting social determinants, such as public policies which are detrimental to youth, and improving community capacities of youth to be advocates for social change. Challenges for future practice and research are articulated.

  10. Reducing rattlesnake-human conflicts

    USGS Publications Warehouse

    Nowak, Erika M.

    2006-01-01

    Arizona is home to 11 species of rattlesnakes. As rapidly growing Arizona communities move into formerly undeveloped landscapes, encounters between people and rattlesnakes increase. As a result, the management of nuisance snakes, or snakes found in areas where people do not want them, is increasingly important. Since 1994, the U.S. Geological Survey (USGS) has conducted research on the behavior and ecology of nuisance rattlesnake in Arizona national park units. A decade of research provides important insights into rattlesnake behavior that can be used by national parks and communities to reduce rattlesnake-human conflicts.

  11. Reduced Vlasov-Maxwell simulations

    NASA Astrophysics Data System (ADS)

    Helluy, Philippe; Navoret, Laurent; Pham, Nhung; Crestetto, Anaïs

    2014-10-01

    In this paper we review two different numerical methods for Vlasov-Maxwell simulations. The first method is based on a coupling between a Discontinuous Galerkin (DG) Maxwell solver and a Particle-In-Cell (PIC) Vlasov solver. The second method only uses a DG approach for the Vlasov and Maxwell equations. The Vlasov equation is first reduced to a space-only hyperbolic system thanks to the finite-element method. The two numerical methods are implemented using OpenCL in order to achieve high performance on recent Graphic Processing Units (GPU).

  12. Reducing Misanthropic Memory Through Self-Awareness: Reducing Bias.

    PubMed

    Davis, Mark D

    2015-01-01

    Two experiments investigated the influence of self-awareness on misanthropic recall. Misanthropic recall is the tendency to recall more negative behaviors dispositionally attributed and positive behaviors situationally attributed than negative behaviors situationally attributed and positive behaviors dispositionally attributed. It was hypothesized that when one is self-aware, more systematic information processing would occur, thereby reducing misanthropic memory and influencing attitudinal judgments. The first experiment used a mirror and the second experiment used a live video to induce self-awareness. Participants were asked to form an impression of a group. The results of both experiments replicated the previously found pattern of misanthropic memory for non-self-aware participants (Ybarra & Stephan, 1996), and revealed less misanthropic recall bias in self-aware participants.

  13. Reduced prefrontal connectivity in psychopathy.

    PubMed

    Motzkin, Julian C; Newman, Joseph P; Kiehl, Kent A; Koenigs, Michael

    2011-11-30

    Linking psychopathy to a specific brain abnormality could have significant clinical, legal, and scientific implications. Theories on the neurobiological basis of the disorder typically propose dysfunction in a circuit involving ventromedial prefrontal cortex (vmPFC). However, to date there is limited brain imaging data to directly test whether psychopathy may indeed be associated with any structural or functional abnormality within this brain area. In this study, we employ two complementary imaging techniques to assess the structural and functional connectivity of vmPFC in psychopathic and non-psychopathic criminals. Using diffusion tensor imaging, we show that psychopathy is associated with reduced structural integrity in the right uncinate fasciculus, the primary white matter connection between vmPFC and anterior temporal lobe. Using functional magnetic resonance imaging, we show that psychopathy is associated with reduced functional connectivity between vmPFC and amygdala as well as between vmPFC and medial parietal cortex. Together, these data converge to implicate diminished vmPFC connectivity as a characteristic neurobiological feature of psychopathy.

  14. FIREhose: Reducing Data from FIRE

    NASA Astrophysics Data System (ADS)

    Fica, Haley Diane; Lambrides, Erini; Faherty, Jackie; Cruz, Kelle L.; BDNYC

    2016-01-01

    Brown dwarfs are stellar objects that do not have enough mass to ignite hydrogen fusion in their core. Their mass is between 0.08 solar masses and the mass of our sun. Brown dwarfs are very bright in the near-infrared wavelength band (0.8- 2.5 microns). We reduced data from the Folded-port InfraRed Echellette (FIRE) instrument on the Magellan Telescope at the Las Campanas Observatory. FIRE is a medium-resolution echelle spectrometer, whose data reduction results in a spectrum of a star. When reducing FIRE data, it is important to account for inconsistencies in the data, such as bad pixels, cosmic rays, and the effects of our atmosphere. Using the FIREhose pipeline, these inconsistencies can be accounted for and corrected using a A0 telluric with a known spectrum. After telluric correcting, the data reduction results in a primed spectrum for an object, which can then be used to determine an object's physical properties, such as atmospheric composition, radial velocity, effective temperature and surface gravity.

  15. Reduced discretization error in HZETRN

    SciTech Connect

    Slaba, Tony C.; Blattnig, Steve R.; Tweed, John

    2013-02-01

    The deterministic particle transport code HZETRN is an efficient analysis tool for studying the effects of space radiation on humans, electronics, and shielding materials. In a previous work, numerical methods in the code were reviewed, and new methods were developed that further improved efficiency and reduced overall discretization error. It was also shown that the remaining discretization error could be attributed to low energy light ions (A < 4) with residual ranges smaller than the physical step-size taken by the code. Accurately resolving the spectrum of low energy light particles is important in assessing risk associated with astronaut radiation exposure. In this work, modifications to the light particle transport formalism are presented that accurately resolve the spectrum of low energy light ion target fragments. The modified formalism is shown to significantly reduce overall discretization error and allows a physical approximation to be removed. For typical step-sizes and energy grids used in HZETRN, discretization errors for the revised light particle transport algorithms are shown to be less than 4% for aluminum and water shielding thicknesses as large as 100 g/cm{sup 2} exposed to both solar particle event and galactic cosmic ray environments.

  16. Interventions to reduce school bullying.

    PubMed

    Smith, Peter K; Ananiadou, Katerina; Cowie, Helen

    2003-10-01

    In the last 2 decades, school bullying has become a topic of public concern and research around the world. This has led to action to reduce the problem. We review interventions targeted at the school level (for example, whole school policy, classroom climate, peer support, school tribunal, and playground improvement), at the class level (for example, curriculum work), and at the individual level (for example, working with specific pupils). Effectiveness of interventions has been sporadically assessed. We review several systematically evaluated, large-scale, school-based intervention programs. Their effectiveness has varied, and we consider reasons for this. We suggest ways to improve the evaluation and comparability of studies, as well as the effectiveness of future interventions.

  17. Moral Violations Reduce Oral Consumption

    PubMed Central

    Chan, Cindy; Van Boven, Leaf; Andrade, Eduardo B.; Ariely, Dan

    2014-01-01

    Consumers frequently encounter moral violations in everyday life. They watch movies and television shows about crime and deception, hear news reports of corporate fraud and tax evasion, and hear gossip about cheaters and thieves. How does exposure to moral violations influence consumption? Because moral violations arouse disgust and because disgust is an evolutionarily important signal of contamination that should provoke a multi-modal response, we hypothesize that moral violations affect a key behavioral response to disgust: reduced oral consumption. In three experiments, compared with those in control conditions, people drank less water and chocolate milk while (a) watching a film portraying the moral violations of incest, (b) writing about moral violations of cheating or theft, and (c) listening to a report about fraud and manipulation. These findings imply that “moral disgust” influences consumption in ways similar to core disgust, and thus provide evidence for the associations between moral violations, emotions, and consumer behavior. PMID:25125931

  18. Moral Violations Reduce Oral Consumption.

    PubMed

    Chan, Cindy; Van Boven, Leaf; Andrade, Eduardo B; Ariely, Dan

    2014-07-01

    Consumers frequently encounter moral violations in everyday life. They watch movies and television shows about crime and deception, hear news reports of corporate fraud and tax evasion, and hear gossip about cheaters and thieves. How does exposure to moral violations influence consumption? Because moral violations arouse disgust and because disgust is an evolutionarily important signal of contamination that should provoke a multi-modal response, we hypothesize that moral violations affect a key behavioral response to disgust: reduced oral consumption. In three experiments, compared with those in control conditions, people drank less water and chocolate milk while (a) watching a film portraying the moral violations of incest, (b) writing about moral violations of cheating or theft, and (c) listening to a report about fraud and manipulation. These findings imply that "moral disgust" influences consumption in ways similar to core disgust, and thus provide evidence for the associations between moral violations, emotions, and consumer behavior.

  19. Reduced vibration motor winding arrangement

    DOEpatents

    Slavik, C.J.; Rhudy, R.G.; Bushman, R.E.

    1997-11-11

    An individual phase winding arrangement having a sixty electrical degree phase belt width for use with a three phase motor armature includes a delta connected phase winding portion and a wye connected phase winding portion. Both the delta and wye connected phase winding portions have a thirty electrical degree phase belt width. The delta and wye connected phase winding portions are each formed from a preselected number of individual coils each formed, in turn, from an unequal number of electrical conductor turns in the approximate ratio of {radical}3. The individual coils of the delta and wye connected phase winding portions may either be connected in series or parallel. This arrangement provides an armature winding for a three phase motor which retains the benefits of the widely known and utilized thirty degree phase belt concept, including improved mmf waveform and fundamental distribution factor, with consequent reduced vibrations and improved efficiency. 4 figs.

  20. Reduced vibration motor winding arrangement

    DOEpatents

    Slavik, Charles J.; Rhudy, Ralph G.; Bushman, Ralph E.

    1997-01-01

    An individual phase winding arrangement having a sixty electrical degree phase belt width for use with a three phase motor armature includes a delta connected phase winding portion and a wye connected phase winding portion. Both the delta and wye connected phase winding portions have a thirty electrical degree phase belt width. The delta and wye connected phase winding portions are each formed from a preselected number of individual coils each formed, in turn, from an unequal number of electrical conductor turns in the approximate ratio of .sqroot.3. The individual coils of the delta and wye connected phase winding portions may either be connected in series or parallel. This arrangement provides an armature winding for a three phase motor which retains the benefits of the widely known and utilized thirty degree phase belt concept, including improved mmf waveform and fundamental distribution factor, with consequent reduced vibrations and improved efficiency.

  1. Reducing stillbirths: interventions during labour

    PubMed Central

    Darmstadt, Gary L; Yakoob, Mohammad Yawar; Haws, Rachel A; Menezes, Esme V; Soomro, Tanya; Bhutta, Zulfiqar A

    2009-01-01

    Background Approximately one million stillbirths occur annually during labour; most of these stillbirths occur in low and middle-income countries and are associated with absent, inadequate, or delayed obstetric care. The low proportion of intrapartum stillbirths in high-income countries suggests that intrapartum stillbirths are largely preventable with quality intrapartum care, including prompt recognition and management of intrapartum complications. The evidence for impact of intrapartum interventions on stillbirth and perinatal mortality outcomes has not yet been systematically examined. Methods We undertook a systematic review of the published literature, searching PubMed and the Cochrane Library, of trials and reviews (N = 230) that reported stillbirth or perinatal mortality outcomes for eight interventions delivered during labour. Where eligible randomised controlled trials had been published after the most recent Cochrane review on any given intervention, we incorporated these new trial findings into a new meta-analysis with the Cochrane included studies. Results We found a paucity of studies reporting statistically significant evidence of impact on perinatal mortality, especially on stillbirths. Available evidence suggests that operative delivery, especially Caesarean section, contributes to decreased stillbirth rates. Induction of labour rather than expectant management in post-term pregnancies showed strong evidence of impact, though there was not enough evidence to suggest superior safety for the fetus of any given drug or drugs for induction of labour. Planned Caesarean section for term breech presentation has been shown in a large randomised trial to reduce stillbirths, but the feasibility and consequences of implementing this intervention routinely in low-/middle-income countries add caveats to recommending its use. Magnesium sulphate for pre-eclampsia and eclampsia is effective in preventing eclamptic seizures, but studies have not demonstrated impact

  2. Reducing waste in Big D

    SciTech Connect

    Woods, R.

    1994-03-01

    The city of Dallas is in a unique position among major metropolitan areas of the US. Despite boasting a population of more than 1 million, which grows by 1.3% each year, and a municipal solid waste (MSW) stream averaging 1.2 million tons per year, the city -- the eighth-largest in the country -- has another 50 years of landfill disposal capacity left. This fact is even more impressive when one considers that Dallas' only municipal facility, known as the McCommas Bluff Landfill, accepted 33% more MSW in 1993 than in 1992. The positive landfill situation, however, does not mean Dallas lacks ambition for recycling and waste reduction. Last, April, the city set an aggressive goal of reducing 40% of its MSW from the landfill by 1997. To help reach this mark over the next three years, the city has banned lead-acid batteries, grass clippings, and leaves from landfills, mandated news and office paper collection, and set up a composting operation at the landfill. At present, Dallas recycles about 13% of its waste. Surprisingly, most of the residential recycling effort has been based on voluntary participation through dozens of drop-off sites scattered around the city, rather than on curbside service. The only curbside program the city is conducting is a once-per-week, blue bag pilot program involving 2,000 Dallas homes.

  3. Reducing power usage on demand

    NASA Astrophysics Data System (ADS)

    Corbett, G.; Dewhurst, A.

    2016-10-01

    The Science and Technology Facilities Council (STFC) datacentre provides large- scale High Performance Computing facilities for the scientific community. It currently consumes approximately 1.5MW and this has risen by 25% in the past two years. STFC has been investigating leveraging preemption in the Tier 1 batch farm to save power. HEP experiments are increasing using jobs that can be killed to take advantage of opportunistic CPU resources or novel cost models such as Amazon's spot pricing. Additionally, schemes from energy providers are available that offer financial incentives to reduce power consumption at peak times. Under normal operating conditions, 3% of the batch farm capacity is wasted due to draining machines. By using preempt-able jobs, nodes can be rapidly made available to run multicore jobs without this wasted resource. The use of preempt-able jobs has been extended so that at peak times machines can be hibernated quickly to save energy. This paper describes the implementation of the above and demonstrates that STFC could in future take advantage of such energy saving schemes.

  4. Neuromuscular Adaptations to Reduced Use

    NASA Technical Reports Server (NTRS)

    Ploutz-Snyder, Lori

    2009-01-01

    This viewgraph presentation reviews the studies done to reduce neuromuscular strength loss during unilateral lower limb suspension (ULLS). Since there are animals that undergo fairly long periods of muscular disuse without any or minimal muscular atrophy, there is an answer to that might be applicable to human in situations that require no muscular use to diminish the effects of muscular atrophy. Three sets of ULLS studies were reviewed indicated that muscle strength decreased more than the muscle mass. The study reviewed exercise countermeasures to combat the atrophy, including: ischemia maintained during Compound muscle action potential (CMAP), ischemia and low load exercise, Japanese kaatsu, and the potential for rehabilitation or situations where heavy loading is undesirable. Two forms of countermeasures to unloading have been successful, (1) high-load resistance training has maintained muscle mass and strength, and low load resistance training with blood flow restriction (LL(sub BFR)). The LL(sub BFR) has been shown to increase muscle mass and strength. There has been significant interest in Tourniquet training. An increase in Growth Hormone(GH) has been noted for LL(sub BFR) exercise. An experimental study with 16 subjects 8 of whom performed ULLS, and 8 of whom performed ULLS and LL(sub BFR) exercise three times per week during the ULLS. Charts show the results of the two groups, showing that performing LL(sub BFR) exercise during 30 days of ULLS can maintain muscle size and strength and even improve muscular endurance.

  5. Yolk androgens reduce offspring survival.

    PubMed Central

    Sockman, K W; Schwabl, H

    2000-01-01

    Females may favour some offspring over others by differential deposition of yolk hormones. In American kestrels (Falco sparverius), we found that yolks of eggs laid late in the sequence of a clutch had more testosterone (T) and androstenedione (A4) than yolks of first-laid eggs. To investigate the effects of these yolk androgens on nestling 'fitness', we injected both T and A4 into the yolks of first-laid eggs and compared their hatching time, nestling growth and nestling survival with those of first-laid eggs in which we injected vehicle as a control. Compared to controls, injection of T and A4 at a dose intended to increase their levels to those of later-laid eggs delayed hatching and reduced nestling growth and survival rates. Yolk androgen treatment of egg 1 had no effect on survival of siblings hatching from subsequently laid eggs. The adverse actions of yolk androgen treatment in the kestrel are in contrast to the favourable actions of yolk T treatment found previously in canaries (Serinus canaria). Additional studies are necessary in order to determine whether the deposition of yolk androgens is an adaptive form of parental favouritism or an adverse by-product of endocrine processes during egg formation. Despite its adaptive significance, such 'transgenerational' effects of steroid hormones may have helped to evolutionarily shape the hormonal mechanisms regulating reproduction. PMID:10983830

  6. Variational integrators for reduced magnetohydrodynamics

    SciTech Connect

    Kraus, Michael; Tassi, Emanuele; Grasso, Daniela

    2016-09-15

    Reduced magnetohydrodynamics is a simplified set of magnetohydrodynamics equations with applications to both fusion and astrophysical plasmas, possessing a noncanonical Hamiltonian structure and consequently a number of conserved functionals. We propose a new discretisation strategy for these equations based on a discrete variational principle applied to a formal Lagrangian. The resulting integrator preserves important quantities like the total energy, magnetic helicity and cross helicity exactly (up to machine precision). As the integrator is free of numerical resistivity, spurious reconnection along current sheets is absent in the ideal case. If effects of electron inertia are added, reconnection of magnetic field lines is allowed, although the resulting model still possesses a noncanonical Hamiltonian structure. After reviewing the conservation laws of the model equations, the adopted variational principle with the related conservation laws is described both at the continuous and discrete level. We verify the favourable properties of the variational integrator in particular with respect to the preservation of the invariants of the models under consideration and compare with results from the literature and those of a pseudo-spectral code.

  7. SRBF: Speckle reducing bilateral filtering.

    PubMed

    Balocco, Simone; Gatta, Carlo; Pujol, Oriol; Mauri, Josepa; Radeva, Petia

    2010-08-01

    Speckle noise negatively affects medical ultrasound image shape interpretation and boundary detection. Speckle removal filters are widely used to selectively remove speckle noise without destroying important image features to enhance object boundaries. In this article, a fully automatic bilateral filter tailored to ultrasound images is proposed. The edge preservation property is obtained by embedding noise statistics in the filter framework. Consequently, the filter is able to tackle the multiplicative behavior modulating the smoothing strength with respect to local statistics. The in silico experiments clearly showed that the speckle reducing bilateral filter (SRBF) has superior performances to most of the state of the art filtering methods. The filter is tested on 50 in vivo US images and its influence on a segmentation task is quantified. The results using SRBF filtered data sets show a superior performance to using oriented anisotropic diffusion filtered images. This improvement is due to the adaptive support of SRBF and the embedded noise statistics, yielding a more homogeneous smoothing. SRBF results in a fully automatic, fast and flexible algorithm potentially suitable in wide ranges of speckle noise sizes, for different medical applications (IVUS, B-mode, 3-D matrix array US).

  8. Restricted sample variance reduces generalizability.

    PubMed

    Lakes, Kimberley D

    2013-06-01

    One factor that affects the reliability of observed scores is restriction of range on the construct measured for a particular group of study participants. This study illustrates how researchers can use generalizability theory to evaluate the impact of restriction of range in particular sample characteristics on the generalizability of test scores and to estimate how changes in measurement design could improve the generalizability of the test scores. An observer-rated measure of child self-regulation (Response to Challenge Scale; Lakes, 2011) is used to examine scores for 198 children (Grades K through 5) within the generalizability theory (GT) framework. The generalizability of ratings within relatively developmentally homogeneous samples is examined and illustrates the effect of reduced variance among ratees on generalizability. Forecasts for g coefficients of various D study designs demonstrate how higher generalizability could be achieved by increasing the number of raters or items. In summary, the research presented illustrates the importance of and procedures for evaluating the generalizability of a set of scores in a particular research context.

  9. Variational integrators for reduced magnetohydrodynamics

    NASA Astrophysics Data System (ADS)

    Kraus, Michael; Tassi, Emanuele; Grasso, Daniela

    2016-09-01

    Reduced magnetohydrodynamics is a simplified set of magnetohydrodynamics equations with applications to both fusion and astrophysical plasmas, possessing a noncanonical Hamiltonian structure and consequently a number of conserved functionals. We propose a new discretisation strategy for these equations based on a discrete variational principle applied to a formal Lagrangian. The resulting integrator preserves important quantities like the total energy, magnetic helicity and cross helicity exactly (up to machine precision). As the integrator is free of numerical resistivity, spurious reconnection along current sheets is absent in the ideal case. If effects of electron inertia are added, reconnection of magnetic field lines is allowed, although the resulting model still possesses a noncanonical Hamiltonian structure. After reviewing the conservation laws of the model equations, the adopted variational principle with the related conservation laws is described both at the continuous and discrete level. We verify the favourable properties of the variational integrator in particular with respect to the preservation of the invariants of the models under consideration and compare with results from the literature and those of a pseudo-spectral code.

  10. Reduced neutral XLPE cable design

    SciTech Connect

    Valli, G.F.; Zawadzki, J.A.; Orton, H.E. )

    1990-04-01

    This paper describes the theoretical, laboratory and economic analyses undertaken to determine the optimum metallic concentric neutral design for its single conductor 750 and 500 kcmil aluminum XLPE 15 kV insulated concentric-neutral type feeder cables. The results suggest that reducing the cross-sectional area of this concentric neutral from the currently-recognized industry standard of 20 percent of the central conductor to 7% results in overall present-worth system cost saving of approximately $3 per conductor meter or approximately 22% of the cable first cost. The neutral configuration ultimately chosen to replace the previous standard 37 - number 14 AWG wires was 2 - 1 inch {times} 5 mil tinned copper tapes overlapped by 25%. Line voltage fault test were run in the high-power laboratory on samples with various neutral configurations to confirm they would successfully pass our worst-case fault duty of 10 kA for 20 cycles (i.e., .33 sec) with no reclosing.

  11. Reduced friction engine tappet construction

    SciTech Connect

    Pieprzak, J.M.; Wilermet, P.A.

    1989-09-19

    This patent describes a tappet construction for the valve train of an internal combustion engine having an element of the valve train engaged by the tappet for moving the same. The tappet having an outer cup-shaped case member with side walls and an essentially flat bottom wall adapted to be engaged by a rotating cam member. The cam member having a circumferential base circle no-load portion and a countoured cam circumferential load portion, the cam member engaging the bottom wall to one side of its center to impart a rotative torque on the case. The case slidably and rotatably receiving therein in back-to-back relationship first and second channel-like members each having spaced side walls joined by a continuous essentially flat end wall, the first member being engageable by a portion of the engine element. The flat end walls of the members being adjacent one another and movable relative to each other to at times form a fluid chamber therebetween, a fluid inlet to the chamber and a source of fluid lubricant under pressure connected to the inlet for supplying lubricant at a pressure level greater than the force of the element and cam member against the first member and case to thereby effect separation of the end walls by a film of lubricant thereby reducing frictional resistance to rotation between the parts.

  12. Regulating environments to reduce obesity.

    PubMed

    Hayne, Cheryl L; Moran, Patricia A; Ford, Mary M

    2004-01-01

    The marked increase in the prevalence of obesity appears to be attributable to environmental conditions that implicitly discourage physical activity while explicitly encouraging the consumption of greater quantities of energy-dense, low-nutrient foods. In the United States food environment, consumers are bombarded with advertising for unhealthy food, and receive inadequate nutritional information, especially at restaurants. In the US school environment children have access to sugary sodas and unhealthy a la carte foods in their cafeterias, at the same time getting inadequate physical activity and nutrition education. In the built environment, sprawl has reduced active living. We describe these environments and explore the potential effects of regulatory measures on these environments. In the United States, regulatory opportunities exist at the national, state and local levels to mandate action and to allocate funds for promising health-promoting strategies. Regulatory approaches, much like litigation, can transform the entire environment in which corporations operate. Even with incomplete enforcement of rules, they send a public message about what is acceptable behavior for corporations and individuals. Additionally, because the United States is party to many multilateral and bilateral trade agreements and is an active participant in the GATT/WTO framework, US regulatory actions promise to have a beneficial impact both domestically and globally.

  13. Bioventing reduces soil cleanup costs

    SciTech Connect

    Leahy, M.C.; Erickson, G.P.

    1995-08-01

    An offshoot technology from soil venting, bioventing offers a win-win solution for soils contaminated with volatile organic compounds (VOCs) and nonvolatile contaminants such as diesel and fuel oil. Using low air flowrates through permeable soils, bioventing injects sufficient oxygen to support naturally-occurring bacteria, which biodegraded the VOCs and other contaminants into benign byproducts. Waste gas can be directly discharged to atmosphere without further treatment. This results in no offgas treatment required. Bioventing is a cost-effective alternative to traditional soil-venting techniques. Soil venting uses air to volatilize organic-compound contamination from the vadose zone, the unsaturated soil layer above groundwater. Unfortunately, this simple-and-fast approach creates a waste offgas that requires further treatment before discharge, thus adding significantly to overall project costs. In contrast, bioventing uses low air flowrates, which require lower capital and operating costs. No offgas treatment further reduces equipment and operating costs and often eliminates air permitting. As in all treatment strategies, the process must meet the cleanup objectives. Bioventing is an alternative technique making inroads into refining and petrochemical soil-remediation applications.

  14. Reducing abortion: the Danish experience.

    PubMed

    Risor, H

    1989-01-01

    In 1987, 20,830 legal abortions were performed in Denmark. 2,845 involved women below the age of 20, and 532 involved women terminating pregnancy after the 12th week. Danish law permits all of its female citizens to have an abortion free-of-charge before the 12th week of pregnancy. After the 12th week, the abortion must be applied for through a committee of 3 members, and all counties in Denmark have a committee. It is felt in Denmark that a woman has a right to an abortion if she decides to have one. It she makes that choice, doctors and nurses are supportive. Since 1970, sex education has been mandatory in Danish schools. Teachers often collaborate closely with school doctors and nurses in this education. All counties are required to have at least 1 clinic that provides contraceptive counselling. It was recently found that the lowest number of pregnancies among teenaged girls was found in a county in Jutland where all 9th grade students visit the county clinic to learn about contraceptives, pregnancy, and abortion. Within 1 year after Copenhagen had adopted this practice, the number of abortions among teenagers declined by 20%. One fourth of all pharmacies also collaborate with schools to promote sex education, instructing students about contraceptives and pregnancy tests. The Danish Family Planning Association has produced a film on abortion, and plans to produce videos on abortion for use in schools. The organization also holds training programs for health care personnel on contraception, pregnancy, and abortion. By means of the practices described above, it is hoped that the number of abortions and unwanted pregnancies in Denmark will be reduced.

  15. Ursolic acid sensitizes radioresistant NSCLC cells expressing HIF-1α through reducing endogenous GSH and inhibiting HIF-1α

    PubMed Central

    Song, Bing; Zhang, Qian; Yu, Maohu; Qi, Xinrong; Wang, Gang; Xiao, Linlin; Yi, Qiyi; Jin, Wensen

    2017-01-01

    In previous studies, the present authors demonstrated that effective sensitization of ionizing radiation-induced death of tumor cells, including non-small cell lung cancer (NSCLC) cells, could be produced by oleanolic acid (OA), a pentacyclic triterpenoid present in plants. In the present study, it was investigated whether ursolic acid (UA), an isomer of OA, had also the capacity of sensitizing radioresistant NSCLC cells. The radioresistant cell line H1299/M-hypoxia inducible factor-1α (HIF-1α) was established by transfection with a recombinant plasmid expressing mutant HIF-1α (M-HIF-1α). Compared with parental H1299 cells and H1299 cells transfected with empty plasmid, H1299/M-HIF-1α cells had lower radiosensitivity. Following the use of UA to treat NSCLC cells, elevation of the radiosensitivity of cells was observed by MTT assay. The irradiated H1299/M-HIF-1α cells were more sensitive to UA pretreatment than the irradiated cells with empty plasmid and control. The alteration of DNA damage in the irradiated cells was further measured using micronucleus (MN) assay. The combination of UA treatment with radiation could induce the increase of cellular MN frequencies, in agreement with the change in the tendency observed in the cell viability assay. It was further shown that the endogenous glutathione (GSH) contents were markedly attenuated in the differently irradiated NSCLC cells with UA (80 µmol/l) pretreatment through glutathione reductase/5,5′-dithiobis-(2-nitrob-enzoic acid) (DTNB) recycling assay. The results revealed that UA treatment alone could effectively decrease the GSH content in H1299/M-HIF-1α cells. In addition, the inhibition of HIF-1α expression in radioresistant cells was confirmed by western blotting. It was then concluded that UA could upregulate the radiosensitivity of NSCLC cells, and in particular reduce the refractory response of cells expressing HIF-1α to ionizing radiation. The primary mechanism is associated with reduction of

  16. 40 CFR 1500.4 - Reducing paperwork.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... environmental issues deserving of study, but also to deemphasize insignificant issues, narrowing the scope of... 1500.4 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.4 Reducing paperwork. Agencies shall reduce excessive paperwork by: (a) Reducing the length of...

  17. 40 CFR 1500.4 - Reducing paperwork.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... environmental issues deserving of study, but also to deemphasize insignificant issues, narrowing the scope of... 1500.4 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.4 Reducing paperwork. Agencies shall reduce excessive paperwork by: (a) Reducing the length of...

  18. 40 CFR 1500.4 - Reducing paperwork.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... environmental issues deserving of study, but also to deemphasize insignificant issues, narrowing the scope of... 1500.4 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.4 Reducing paperwork. Agencies shall reduce excessive paperwork by: (a) Reducing the length of...

  19. 40 CFR 1500.4 - Reducing paperwork.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... environmental issues deserving of study, but also to deemphasize insignificant issues, narrowing the scope of... 1500.4 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.4 Reducing paperwork. Agencies shall reduce excessive paperwork by: (a) Reducing the length of...

  20. 21 CFR 582.5375 - Iron reduced.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Iron reduced. 582.5375 Section 582.5375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS... 1 § 582.5375 Iron reduced. (a) Product. Iron reduced. (b) Conditions of use. This substance...

  1. Reducing Sugar in Children's Diets: Why? How?

    ERIC Educational Resources Information Center

    Rogers, Cosby S.; Morris, Sandra S.

    1986-01-01

    Maintains that sugar intake should be reduced in young children's diets because of its link to dental cavities, poor nutrition, and obesity. Reducing the focus on sweetness, limiting sugar consumption, and using natural sources of sweetness and other treats are ways to help reduce sugar intake. (BB)

  2. A Start Toward Micronucleus-Based Decompression Models; Altitude Decompression

    NASA Technical Reports Server (NTRS)

    Van Liew, H. D.; Conkin, Johnny

    2007-01-01

    Do gaseous micronuclei trigger the formation of bubbles in decompression sickness (DCS)? Most previous instructions for DCS prevention have been oriented toward supersaturated gas in tissue. We are developing a mathematical model that is oriented toward the expected behavior of micronuclei. The issue is simplified in altitude decompressions because the aviator or astronaut is exposed only to decompression, whereas in diving there is a compression before the decompression. The model deals with four variables: duration of breathing of 100% oxygen before going to altitude (O2 prebreathing), altitude of the exposure, exposure duration, and rate of ascent. Assumptions: a) there is a population of micronuclei of various sizes having a range of characteristics, b) micronuclei are stable until they grow to a certain critical nucleation radius, c) it takes time for gas to diffuse in or out of micronuclei, and d) all other variables being equal, growth of micronuclei upon decompression is more rapid at high altitude because of the rarified gas in the micronuclei. To estimate parameters, we use a dataset of 4,756 men in altitude chambers exposed to various combinations of the model s variables. The model predicts occurrence of DCS symptoms quite well. It is notable that both the altitude chamber data and the model show little effect of O2 prebreathing until it lasts more than 60 minutes; this is in contrast to a conventional idea that the benefit of prebreathing is directly due to exponential washout of tissue nitrogen. The delay in response to O2 prebreathing can be interpreted as time required for outward diffusion of nitrogen; when the micronuclei become small enough, they are disabled, either by crushing or because they cannot expand to a critical nucleation size when the subject ascends to altitude.

  3. Micronucleus frequency in buccal mucosa cells of mobile phone users.

    PubMed

    Hintzsche, Henning; Stopper, Helga

    2010-03-01

    Mobile phones are being used extensively throughout the world, with more than four billion accounts existing in 2009. This technology applies electromagnetic radiation in the microwave range. Health effects of this radiation have been subject of debate for a long time, both within the scientific community and within the general public. This study investigated the effect of mobile phone use on genomic instability of the human oral cavity's mucosa cells. 131 Individuals donated buccal mucosa cells extracted by slightly scraping the oral cavity with a cotton swab. Every participant filled out a questionnaire about mobile phone use including duration of weekly use, overall period of exposure and headset usage. 13 Individuals did not use mobile phones at all, 85 reported using the mobile phone for three hours per week or less, and 33 reported use of more than three hours per week. Additionally, information on age, gender, body weight, smoking status, medication and nutrition was retrieved. For staining of the cells a procedure using alpha-tubulin-antibody and chromomycin A(3) was applied. Micronuclei and other markers were evaluated in 1000 cells per individual at the microscope. A second scorer counted another 1000 cells, resulting in 2000 analyzed cells per individual. Mobile phone use did not lead to a significantly increased frequency of micronuclei.

  4. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... marrow extracted, and preparations made and stained (test techniques described in the references under... test techniques described in the references under paragraphs (g)(3), (g)(4), (g)(5), and (g)(6) of this... administered by this route. Animals may be housed individually, or caged in small groups of the same sex....

  5. Genotoxic evaluation of pirfenidone using erythrocyte rodent micronucleus assay.

    PubMed

    Alcántar-Díaz, Blanca E; Gómez-Meda, Belinda C; Zúñiga-González, Guillermo M; Zamora-Perez, Ana L; González-Cuevas, Jaime; Alvarez-Rodríguez, Bertha A; Sánchez-Parada, María Guadalupe; García-Bañuelos, Jesús J; Armendáriz-Borunda, Juan

    2012-08-01

    Pirfenidone is a non-steroidal antifibrotic compound that has been proposed in clinical protocols and experimental studies as a pharmacological treatment for fibroproliferative diseases. The objective of this study was to determine the genotoxicity or cytotoxicity of three doses of pirfenidone using the micronuclei test in peripheral blood erythrocytes of rodent models. Pirfenidone was administered orally to Balb-C mice for 3 days, and also was administered topically to hairless Sprague Dawley rats during the final stage of gestation. Mice were sampled every 24 h over the course of 6 days; pregnant rats were sampled every 24 h during the last 6 days of gestation, and pups were sampled at birth. Blood smears were analyzed and the frequencies of micronucleated erythrocytes (MNEs), micronucleated polychromatic erythrocytes (MNPCEs), and the proportion of polychromatic erythrocytes (PCEs), were recorded in samples from mice, pregnant rats and rat neonates. Increases in MN frequencies (p<0.03) were noted only in the positive control groups. No genotoxic effects or decreased PCE values were observed neither in newborn rats transplacentally exposed to pirfenidone, or in two adult rodent models when pirfenidone was administered orally or topically.

  6. Micronucleus formation causes perpetual unilateral chromosome inheritance in mouse embryos

    PubMed Central

    Vázquez-Diez, Cayetana; Yamagata, Kazuo; Trivedi, Shardul; Haverfield, Jenna; FitzHarris, Greg

    2016-01-01

    Chromosome segregation defects in cancer cells lead to encapsulation of chromosomes in micronuclei (MN), small nucleus-like structures within which dangerous DNA rearrangements termed chromothripsis can occur. Here we uncover a strikingly different consequence of MN formation in preimplantation development. We find that chromosomes from within MN become damaged and fail to support a functional kinetochore. MN are therefore not segregated, but are instead inherited by one of the two daughter cells. We find that the same MN can be inherited several times without rejoining the principal nucleus and without altering the kinetics of cell divisions. MN motion is passive, resulting in an even distribution of MN across the first two cell lineages. We propose that perpetual unilateral MN inheritance constitutes an unexpected mode of chromosome missegregation, which could contribute to the high frequency of aneuploid cells in mammalian embryos, but simultaneously may serve to insulate the early embryonic genome from chromothripsis. PMID:26729872

  7. Micronucleus formation causes perpetual unilateral chromosome inheritance in mouse embryos.

    PubMed

    Vázquez-Diez, Cayetana; Yamagata, Kazuo; Trivedi, Shardul; Haverfield, Jenna; FitzHarris, Greg

    2016-01-19

    Chromosome segregation defects in cancer cells lead to encapsulation of chromosomes in micronuclei (MN), small nucleus-like structures within which dangerous DNA rearrangements termed chromothripsis can occur. Here we uncover a strikingly different consequence of MN formation in preimplantation development. We find that chromosomes from within MN become damaged and fail to support a functional kinetochore. MN are therefore not segregated, but are instead inherited by one of the two daughter cells. We find that the same MN can be inherited several times without rejoining the principal nucleus and without altering the kinetics of cell divisions. MN motion is passive, resulting in an even distribution of MN across the first two cell lineages. We propose that perpetual unilateral MN inheritance constitutes an unexpected mode of chromosome missegregation, which could contribute to the high frequency of aneuploid cells in mammalian embryos, but simultaneously may serve to insulate the early embryonic genome from chromothripsis.

  8. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... will be sufficient. Where human exposure to chemicals may be sex-specific, as for example with some... treatment up to 14 days, and 1,000 mg/kg/body weight/day for treatment longer than 14 days. Expected human... considered non-mutagenic in this test. (iii) Although most experiments will give clearly positive or...

  9. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... will be sufficient. Where human exposure to chemicals may be sex-specific, as for example with some... treatment up to 14 days, and 1,000 mg/kg/body weight/day for treatment longer than 14 days. Expected human... considered non-mutagenic in this test. (iii) Although most experiments will give clearly positive or...

  10. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... will be sufficient. Where human exposure to chemicals may be sex-specific, as for example with some... treatment up to 14 days, and 1,000 mg/kg/body weight/day for treatment longer than 14 days. Expected human... considered non-mutagenic in this test. (iii) Although most experiments will give clearly positive or...

  11. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... presence or absence of a kinetochore or centromeric DNA in the micronuclei. The frequency of micronucleated... it allows consideration of factors of in vivo metabolism, pharmacokinetics and DNA-repair processes... stained. The use of a DNA specific stain (e.g. acridine orange (techniques described in the...

  12. Reduced Toxicity Fuel Satellite Propulsion System

    NASA Technical Reports Server (NTRS)

    Schneider, Steven J. (Inventor)

    2001-01-01

    A reduced toxicity fuel satellite propulsion system including a reduced toxicity propellant supply for consumption in an axial class thruster and an ACS class thruster. The system includes suitable valves and conduits for supplying the reduced toxicity propellant to the ACS decomposing element of an ACS thruster. The ACS decomposing element is operative to decompose the reduced toxicity propellant into hot propulsive gases. In addition the system includes suitable valves and conduits for supplying the reduced toxicity propellant to an axial decomposing element of the axial thruster. The axial decomposing element is operative to decompose the reduced toxicity propellant into hot gases. The system further includes suitable valves and conduits for supplying a second propellant to a combustion chamber of the axial thruster, whereby the hot gases and the second propellant auto-ignite and begin the combustion process for producing thrust.

  13. Escherichia coli growth under modeled reduced gravity

    NASA Technical Reports Server (NTRS)

    Baker, Paul W.; Meyer, Michelle L.; Leff, Laura G.

    2004-01-01

    Bacteria exhibit varying responses to modeled reduced gravity that can be simulated by clino-rotation. When Escherichia coli was subjected to different rotation speeds during clino-rotation, significant differences between modeled reduced gravity and normal gravity controls were observed only at higher speeds (30-50 rpm). There was no apparent affect of removing samples on the results obtained. When E. coli was grown in minimal medium (at 40 rpm), cell size was not affected by modeled reduced gravity and there were few differences in cell numbers. However, in higher nutrient conditions (i.e., dilute nutrient broth), total cell numbers were higher and cells were smaller under reduced gravity compared to normal gravity controls. Overall, the responses to modeled reduced gravity varied with nutrient conditions; larger surface to volume ratios may help compensate for the zone of nutrient depletion around the cells under modeled reduced gravity.

  14. Reducing energy costs in nursing homes

    SciTech Connect

    Not Available

    1981-01-01

    The handbook presents ideas and techniques for energy conservation in nursing homes. Case studies were developed of nursing homes located in different parts of the US. The typical nursing home assessed was proprietary, of intermediate-care level, medicaid-certified, and had less than 200 beds. Specific energy conservation measures were analyzed to determine the energy and dollar savings that could be realized. These include reducing heat loss through the building shell; reducing hot water costs; recovering the heat generated by dryers; reducing lighting costs; reducing heating and cooling costs, and analyzing fuels and fuel rates. A case for converting electric clothes dryers to gas was analyzed. (MCW)

  15. Reducing pawing in horses using positive reinforcement.

    PubMed

    Fox, Adam E; Belding, Devon L

    2015-12-01

    Aversive control is a common method to reduce undesirable behavior in horses. However, it often results in unintended negative side effects, including potential abuse of the animal. Procedures based on positive reinforcement, such as differential reinforcement of other behavior (DRO), may reduce undesirable behaviors with fewer negative consequences. The current study used DRO schedules to reduce pawing using a multiple baseline design across 3 horses. Results indicated that DRO schedules were effective at reducing pawing. However, individual differences in sensitivity to DRO and reinforcer efficacy may be important considerations.

  16. The Consumer's Handbook for Reducing Solid Waste.

    ERIC Educational Resources Information Center

    Environmental Protection Agency, Washington, DC.

    This profusely illustrated and informally written booklet describes how people can help solve a growing problem--garbage. The following 12 tips are presented: (1) Reduce the amount of unnecessary packaging; (2) Adopt practices that reduce waste toxicity; (3) Consider reusable products; (4) Maintain and repair durable products; (5) Reuse bags,…

  17. Simple Potentiometric Determination of Reducing Sugars

    ERIC Educational Resources Information Center

    Moresco, Henry; Sanson, Pedro; Seoane, Gustavo

    2008-01-01

    In this article a potentiometric method for reducing sugar quantification is described. Copper(II) ion reacts with the reducing sugar (glucose, fructose, and others), and the excess is quantified using a copper wire indicator electrode. In order to accelerate the kinetics of the reaction, working conditions such as pH and temperature must be…

  18. Welfare Reform and Reducing Teen Pregnancy.

    ERIC Educational Resources Information Center

    Sawhill, Isabel V.

    2000-01-01

    Most adolescent mothers are unmarried and on welfare. Congress enacted new welfare legislation that emphasizes reducing teen pregnancy and requiring work, but states are reluctant to meet this challenge. Discusses child poverty's new face, public policy and culture wars, welfare reform, and social norms. Concludes that reducing unwed parenthood…

  19. Tools to Reduce Waste in Schools

    ERIC Educational Resources Information Center

    US Environmental Protection Agency, 2007

    2007-01-01

    This guide was produced to help schools and school districts reduce the amount of waste they generate It shows how to start a waste reduction program or expand an existing one. The booklet shows how such programs can benefit schools, communities, and the environment by reducing, reusing, and recycling waste. Each section--schools, school…

  20. Partial turbo detection with reduced complexity

    NASA Astrophysics Data System (ADS)

    Ouardi, Aissa; Djebbari, A.; Bouazza, B. S.

    2011-06-01

    In this article, we propose a novel method for reducing the complexity of the turbo detector MAP (maximum a posteriori). The basic idea consists in turbo detecting a part of intersymbol interference (ISI) after decomposing the channel in two parts. We show that we can reduce the trellis complexity in the turbo process at a certain cost, i.e. performance loss.

  1. Mesenchymal Stem Cells Reduce Murine Atherosclerosis Development

    PubMed Central

    Frodermann, Vanessa; van Duijn, Janine; van Pel, Melissa; van Santbrink, Peter J.; Bot, Ilze; Kuiper, Johan; de Jager, Saskia C. A.

    2015-01-01

    Mesenchymal stem cells (MSCs) have regenerative properties, but recently they were also found to have immunomodulatory capacities. We therefore investigated whether MSCs could reduce atherosclerosis, which is determined by dyslipidaemia and chronic inflammation. We adoptively transferred MSCs into low-density lipoprotein-receptor knockout mice and put these on a Western-type diet to induce atherosclerosis. Initially after treatment, we found higher levels of circulating regulatory T cells. In the long-term, overall numbers of effector T cells were reduced by MSC treatment. Moreover, MSC-treated mice displayed a significant 33% reduction in circulating monocytes and a 77% reduction of serum CCL2 levels. Most strikingly, we found a previously unappreciated effect on lipid metabolism. Serum cholesterol was reduced by 33%, due to reduced very low-density lipoprotein levels, likely a result of reduced de novo hepatic lipogenesis as determined by a reduced expression of Stearoyl-CoA desaturase-1 and lipoprotein lipase. MSCs significantly affected lesion development, which was reduced by 33% in the aortic root. These lesions contained 56% less macrophages and showed a 61% reduction in T cell numbers. We show here for the first time that MSC treatment affects not only inflammatory responses but also significantly reduces dyslipidaemia in mice. This makes MSCs a potent candidate for atherosclerosis therapies. PMID:26490642

  2. Social Work Practice to Reduce Underachievement.

    ERIC Educational Resources Information Center

    Barth, Richard P.

    1988-01-01

    Social workers' direct work with students can help to reduce the disparity between educational ability and achievement. Interventions with low achievers must include fostering linkages between home and school. Consultation and followup are necessary components for reducing underachievement. The intervention must be done in conjunction with school…

  3. Reducing the Deficit: Spending and Revenue Options

    DTIC Science & Technology

    1994-03-01

    efforts-- defense and international discretionary spending , domestic discretion- ary spending , and entitlements and other mandatory spending . The last...9 TWO DEFENSE AND INTERNATIONAL DISCRETIONARY SPENDING 13 Threats to National Security ....................... 13 Economic and...Reducing Defense Spending .............................. 16 Stratezic Prourams DEF-01 Reduce Nuclear Delivery Systems Within Overall Limits of START II

  4. Soluble calcium amendments: reducing pathogen losses

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Flue gas desulfurization (FGD) gypsum is a byproduct of coal-fired power plants. Its application to agricultural fields may increase water infiltration, reduce soil erosion, and decrease nutrient losses from applications of animal manures. It may also reduce fecal bacterial contamination of surface ...

  5. Multiclass Reduced-Set Support Vector Machines

    NASA Technical Reports Server (NTRS)

    Tang, Benyang; Mazzoni, Dominic

    2006-01-01

    There are well-established methods for reducing the number of support vectors in a trained binary support vector machine, often with minimal impact on accuracy. We show how reduced-set methods can be applied to multiclass SVMs made up of several binary SVMs, with significantly better results than reducing each binary SVM independently. Our approach is based on Burges' approach that constructs each reduced-set vector as the pre-image of a vector in kernel space, but we extend this by recomputing the SVM weights and bias optimally using the original SVM objective function. This leads to greater accuracy for a binary reduced-set SVM, and also allows vectors to be 'shared' between multiple binary SVMs for greater multiclass accuracy with fewer reduced-set vectors. We also propose computing pre-images using differential evolution, which we have found to be more robust than gradient descent alone. We show experimental results on a variety of problems and find that this new approach is consistently better than previous multiclass reduced-set methods, sometimes with a dramatic difference.

  6. Reduced Baroclinicity During Martian Global Dust Storms

    NASA Astrophysics Data System (ADS)

    Battalio, Joseph; Szunyogh, Istvan; Lemmon, Mark

    2015-11-01

    The eddy kinetic energy equation is applied to the Mars Analysis Correction Data Assimilation (MACDA) dataset during the pre-winter solstice period for the northern hemisphere of Mars. Traveling waves are triggered by geopotential flux convergence, grow baroclinically, and decay barotropically. Higher optical depth increases the static stability, which reduces vertical and meridional heat fluxes. Traveling waves during a global dust storm year develop a mixed baroclinic/barotropic growth phase before decaying barotropically. Baroclinic energy conversion is reduced during the global dust storm, but eddy intensity is undiminished. Instead, the frequency of storms is reduced due to a stabilized vertical profile.

  7. Reducing urinary tract infections in catheterised patients.

    PubMed

    Howe, Pam; Adams, John

    2015-01-20

    Urinary tract infections in catheterised patients continue to present a challenge in reducing healthcare-associated infection. In this article, an infection prevention and control team in one NHS trust reports on using audit results to focus attention on measures to reduce bacterial infections. Educational initiatives have an important role in reducing infection, but there is no single solution to the problem. Practice can be improved using a multi-targeted approach, peer review and clinical audit to allow for shared learning and experiences. These, along with informal education in the clinical area and more formal classroom lectures, can ultimately lead to improved patient outcomes.

  8. Reducibility of Matrix Equations Containing Several Parameters.

    DTIC Science & Technology

    1981-12-01

    AD-AI15 568 AIR FORCE INST OF TECH WRIGHT-PATTERSON AFB OH SCHOO;-ETC EF G 12 1ADA1551 REDUCIBILITY OF MATRIX EQUATIONS CONTAINING SEVERAL...PARAMETERS.E U)CA E UNCLASSIFIED AFIT/GE/RA/81D-1 N P11111111II soonhh Eu;o I. ’Trm * a, ~t- NMI 4 i’- 00Nt. met r~ REDUCIBILITY OF MATRIX EQUATIONS CONTAINING...1 REDUCIBILITY OF MATRIX EQUATIONS CONTAINING SEVERAL PARAMETERS THESIS Presented to the Faculty of the School of Engineering of the Air Force

  9. Top Five Lifestyle Changes to Reduce Cholesterol

    MedlinePlus

    Top 5 lifestyle changes to improve your cholesterol Lifestyle changes can help reduce cholesterol, keep you off cholesterol-lowering medications or enhance the effect of your medications. Here are five lifestyle ...

  10. Deep brain stimulation to reduce sexual drive

    PubMed Central

    Fuss, Johannes; Auer, Matthias K.; Biedermann, Sarah V.; Briken, Peer; Hacke, Werner

    2015-01-01

    To date there are few treatment options to reduce high sexual drive or sexual urges in paraphilic patients with a risk for sexual offending. Pharmacological therapy aims to reduce sexual drive by lowering testosterone at the cost of severe side effects. We hypothesize that high sexual drive could also be reduced with deep brain stimulation (DBS) of circuits that generate sexual drive. This approach would help to avoid systemic side effects of antiandrogenic drug therapies. So far the best investigated target to reduce sexual drive is the ventromedial hypothalamus, which was lesioned unilaterally and bilaterally by stereotaxic interventions in paraphilic patients in the 1970s. Here, we discuss DBS as a treatment strategy in patients with severe paraphilic disorders with a serious risk of sexual offending. There are profound ethical and practical issues associated with DBS treatment of paraphilic patients that must be solved before considering such a treatment approach. PMID:26057198

  11. 49 CFR 609.23 - Reduced fare.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... TRANSPORTATION TRANSPORTATION FOR ELDERLY AND HANDICAPPED PERSONS § 609.23 Reduced fare. Applicants for financial... Administrator may prescribe, that the rates charged elderly and handicapped persons during non-peak hours...

  12. 49 CFR 609.23 - Reduced fare.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... TRANSPORTATION TRANSPORTATION FOR ELDERLY AND HANDICAPPED PERSONS § 609.23 Reduced fare. Applicants for financial... Administrator may prescribe, that the rates charged elderly and handicapped persons during non-peak hours...

  13. Optimal Microstructures Drag Reducing Mechanism of Riblets

    NASA Astrophysics Data System (ADS)

    Friedmann, Elfriede; Richter, Thomas

    2011-09-01

    We consider an optimal shape design problem of periodically distributed three-dimensional microstructures on surfaces of swimming bodies in order to reduce their drag. Our model is restricted to the flow in the viscous sublayer of the boundary layer of a turbulent flow. The costs for the optimization problem are very high because the three-dimensional flow equations have to be solved several times. We avoid this problem by approximations: the microscopic optimization problem is reduced applying homogenization. Considering a special geometry (riblets) the resulting so-called macroscopic optimization problem can be additionally reduced to a two-dimensional problem. We analyze the drag reducing mechanism of riblets which are believed to be optimal structures. Therefore we perform direct simulations on the total rough channel for different shapes of microstructures: riblets and fully three-dimensional structures.

  14. Auto Accidents: Reducing Frequency, Increasing Recovery.

    ERIC Educational Resources Information Center

    Comeaux, Linda Atkins

    1988-01-01

    Careful hiring, monitoring, training, discipline, and safety policies will reduce school automobile and bus accidents. Guidelines are offered for accident reporting, claim handling, and dealing with insurance adjusters. (MLF)

  15. Reducing the atmospheric impact of wet slaking

    SciTech Connect

    B.D. Zubitskii; G.V. Ushakov; B.G. Tryasunov; A.G.Ushakov

    2009-05-15

    Means of reducing the atmospheric emissions due to the wet slaking of coke are considered. One option, investigated here, is to remove residual active silt and organic compounds from the biologically purified wastewater sent for slaking, by coagulation and flocculation.

  16. Vaccine Reduces HPV Infections in Young Men

    Cancer.gov

    An international randomized clinical trial has shown that the vaccine Gardasil can reduce the incidence of anogenital human papillomavirus (HPV) infections in young men 16 to 26 years of age at the time of vaccination.

  17. Reducing health inequalities for older LGBTQ+ people.

    PubMed

    Thomas, Ben

    2016-10-26

    The recent LGBTQ+ history exhibition Speak Out London, Diversity City presented a fantastic collection of stories, documents and photographs from LGBTQ+ Londoners. It also provided a reminder of how far we have come in reducing stigma, prejudice and discrimination.

  18. Dual photochemical replenisher system reduces chemical losses

    NASA Technical Reports Server (NTRS)

    Kolber, J. M.

    1967-01-01

    Dual replenisher system reduces chemical losses and maintains optimum solution concentration during long nonprocessing cycles of photo processing machines. Using a single 3-position switch and solenoid control valves, the system provides instantaneous flow control to each processing tank.

  19. New approaches to reduce radiation exposure

    PubMed Central

    Hill, Kevin D.; Einstein, Andrew J.

    2015-01-01

    Exposure to ionizing radiation is associated with a long term risk of health effects including cancer. Radiation exposure to the U.S. population from cardiac imaging has increased markedly over the past three decades. Initiatives to reduce radiation exposure have focused on the tenets of appropriate study “justification” and “optimization” of imaging protocols. This article reviews ways to optimally reduce radiation dose across the spectrum of cardiac imaging. PMID:25962784

  20. Reduced gravity - A new biomedical research environment

    NASA Technical Reports Server (NTRS)

    Snyder, Robert S.

    1989-01-01

    Experiment programs for continuous flow electrophoresis and protein crystal growth are described to demonstrate the utility of the reduced gravity environment for scientific research. The advantages of the reduced gravity environment are outlined. The results of experiments on the Space Shuttle using the Continuous Flow Electrophoresis System and crystal growth experiments on Spacelab-1 and the Space Shuttle are examined, noting the importance of microgravity research.

  1. Boiler burden reduced at Bedford site.

    PubMed

    Horsley, Chris

    2011-10-01

    With the NHS aiming to reduce its 2007 carbon footprint by 10% by 2015, Chris Horsley, managing director of Babcock Wanson UK, a provider of industrial boilers and burners, thermal oxidisers, air treatment, water treatment, and associated services, looks at how one NHS Trust has approached the challenge, and considerably reduced its carbon emissions, by refurbishing its boiler house and moving from oil to gas-fired steam generation.

  2. Interventions to Reduce Myopia Progression in Children.

    PubMed

    Tay, Su Ann; Farzavandi, Sonal; Tan, Donald

    2017-03-01

    Efforts to reduce the progression of myopia in childhood are on the rise, due to an increasing incidence of myopia worldwide and its associated sight-threatening complications. Interventions are aimed at reducing myopia in childhood and include environmental considerations, spectacles, contact lenses, and pharmacological agents. We reviewed recent literature with interventions aimed at reducing myopia progression in children and found that a number of interventions were significant in reducing the progression of myopia. Of these interventions, atropine showed the largest dose-related effect on myopia progression control. Although higher doses are associated with side effects of pupil dilatation, loss of accommodation, near vision blur, and rebound phenomenon, low-dose atropine has also been shown to provide effective myopia control with minimal side effects and rebound. To a lesser degree, bifocal soft contact lenses have also been shown to be effective in reducing the progression of myopia, though compliance is an issue. Similarly, orthokeratology lenses have also been shown to be effective in reducing axial length elongation and myopia progression, though long-term data on its rebound effects are unavailable.

  3. Model diagnostics in reduced-rank estimation

    PubMed Central

    Chen, Kun

    2016-01-01

    Reduced-rank methods are very popular in high-dimensional multivariate analysis for conducting simultaneous dimension reduction and model estimation. However, the commonly-used reduced-rank methods are not robust, as the underlying reduced-rank structure can be easily distorted by only a few data outliers. Anomalies are bound to exist in big data problems, and in some applications they themselves could be of the primary interest. While naive residual analysis is often inadequate for outlier detection due to potential masking and swamping, robust reduced-rank estimation approaches could be computationally demanding. Under Stein's unbiased risk estimation framework, we propose a set of tools, including leverage score and generalized information score, to perform model diagnostics and outlier detection in large-scale reduced-rank estimation. The leverage scores give an exact decomposition of the so-called model degrees of freedom to the observation level, which lead to exact decomposition of many commonly-used information criteria; the resulting quantities are thus named information scores of the observations. The proposed information score approach provides a principled way of combining the residuals and leverage scores for anomaly detection. Simulation studies confirm that the proposed diagnostic tools work well. A pattern recognition example with hand-writing digital images and a time series analysis example with monthly U.S. macroeconomic data further demonstrate the efficacy of the proposed approaches. PMID:28003860

  4. Coal ash behavior in reducing environments

    SciTech Connect

    Benson, S.A.; Erickson, T.A.; Brekke, D.W.; Folkedahl, B.C.; Tibbetts, J.E.; Nowok, J.W.

    1994-10-01

    This project is a four-year program designed to investigate the transformations and properties of coal ash in reducing environment systems. This project is currently midway through its third year. The work to date has emphasized four areas of research: (1) the development of quantitative techniques to analyze reduced species, (2) the production of gasification-type samples under closely controlled conditions, (3) the systematic gasification of specific coals to produce information about their partitioning during gasification, and (4) the study of the physical properties of ashes and slags under reducing atmospheres. The project is organized into three tasks which provide a strong foundation for the project. Task 1, Analytical Methods Development, has concentrated on the special needs of analyzing samples produced under a reducing atmosphere as opposed to the more often studied combustion systems. Task 2, Inorganic Partitioning and Ash Deposition, has focused on the production of gasification-type samples under closely controlled conditions for the study of inorganic partitioning that may lead to deposition. Task 3, Ash and Slag Physical Properties, has made large gains in the areas of sintering and strength development of coal ashes under reducing atmospheres for the evaluation of deposition problems. Results are presented for all three tasks.

  5. Reduced pressure quenching oil and distortion

    SciTech Connect

    Asada, S.; Ogino, M.

    1996-12-31

    Cooling process observed in a quenching oil`s cooling curve determination by JIS silver probe method, has been divided into three stages, vapor blanket stage, boiling stage and convection stage. Under reduced pressure vaporization is accelerated and extend the vapor blanket stage which shift the position of boiling stage the fastest of cooling speed among the cooling process toward low temperature side. Taking advantage of this behavior in quenching under reduced pressure, it is possible to improve quench hardenability by controlling reduced pressure. Vapor pressure of quenching oil increases under very high vacuum and accelerates vapor blanket formation and covers the material with more vapor blanket, resulting in reduction of cooling speed. Excessive vapor blanket covering the material will lead to partially uneven quenching of the treated material caused by uneven conditions by partial decomposition. Making vapor blanket distribution more even and to optimize uniform coating condition enables to prevent heat treatment distortion caused by uneven quenching conditions.

  6. Active structures to reduce torsional vibrations

    NASA Astrophysics Data System (ADS)

    Matthias, M.; Schlote, D.; Atzrodt, H.

    2013-03-01

    This paper describes the development of different active measures to reduce torsional vibrations in power trains. The measures are based on concepts developed for active mounts to reduce the transmission of structure-borne sound. To show the potential of these active measures and investigate their mode of operation to influence torsional vibrations, numerical simulations of powertrains with different active measures were done. First experimental results from tests on an experimental (reduced size) power train were used to align the numerical models. The work was done within the project 'LOEWE-Zentrum AdRIA: Adaptronik - Research, Innovation, Application' funded by the German federal state of Hessen, and the Project AKTos: 'Active control of torsional vibrations by coupling elements' placed in the research Framework program 'Navigation and Maritime Technology for the 21st Century' funded by the German Federal Ministry of Economics and Technology.

  7. Local stressors reduce coral resilience to bleaching.

    PubMed

    Carilli, Jessica E; Norris, Richard D; Black, Bryan A; Walsh, Sheila M; McField, Melanie

    2009-07-22

    Coral bleaching, during which corals lose their symbiotic dinoflagellates, typically corresponds with periods of intense heat stress, and appears to be increasing in frequency and geographic extent as the climate warms. A fundamental question in coral reef ecology is whether chronic local stress reduces coral resistance and resilience from episodic stress such as bleaching, or alternatively promotes acclimatization, potentially increasing resistance and resilience. Here we show that following a major bleaching event, Montastraea faveolata coral growth rates at sites with higher local anthropogenic stressors remained suppressed for at least 8 years, while coral growth rates at sites with lower stress recovered in 2-3 years. Instead of promoting acclimatization, our data indicate that background stress reduces coral fitness and resilience to episodic events. We also suggest that reducing chronic stress through local coral reef management efforts may increase coral resilience to global climate change.

  8. Mistake proofing: changing designs to reduce error

    PubMed Central

    Grout, J R

    2006-01-01

    Mistake proofing uses changes in the physical design of processes to reduce human error. It can be used to change designs in ways that prevent errors from occurring, to detect errors after they occur but before harm occurs, to allow processes to fail safely, or to alter the work environment to reduce the chance of errors. Effective mistake proofing design changes should initially be effective in reducing harm, be inexpensive, and easily implemented. Over time these design changes should make life easier and speed up the process. Ideally, the design changes should increase patients' and visitors' understanding of the process. These designs should themselves be mistake proofed and follow the good design practices of other disciplines. PMID:17142609

  9. Lasercom system architecture with reduced complexity

    NASA Technical Reports Server (NTRS)

    Lesh, James R. (Inventor); Chen, Chien-Chung (Inventor); Ansari, Homayoon (Inventor)

    1994-01-01

    Spatial acquisition and precision beam pointing functions are critical to spaceborne laser communication systems. In the present invention, a single high bandwidth CCD detector is used to perform both spatial acquisition and tracking functions. Compared to previous lasercom hardware design, the array tracking concept offers reduced system complexity by reducing the number of optical elements in the design. Specifically, the design requires only one detector and one beam steering mechanism. It also provides the means to optically close the point-ahead control loop. The technology required for high bandwidth array tracking was examined and shown to be consistent with current state of the art. The single detector design can lead to a significantly reduced system complexity and a lower system cost.

  10. Targets set to reduce Lake Erie algae

    USGS Publications Warehouse

    Evans, Mary

    2016-01-01

    In February 2016, the Great Lakes Executive Committee, which oversees the implementation of the Great Lakes Water Quality Agreement (GLWQA) between the U.S. and Canada, approved phosphorus loading targets for Lake Erie to reduce the size of harmful algal blooms (HABs), reduce the presence of the low oxygen zone in the central basin, and protect nearshore water quality. The targets are set with respect to the nutrient loads calculated for 2008. To reduce the impacts of HABs on Lake Erie a target was set of a 40 percent reduction in total and soluble reactive phosphorus loads in the spring from two Canadian rivers and several Michigan and Ohio rivers, especially the Maumee River (https://binational.net/2016/02/22/ finalptargets-ciblesfinalesdep/). States and the province of Ontario are already developing Domestic Action Plans to accomplish the reductions and scientists are developing research and monitoring plans to assess progress.

  11. Moral elevation reduces prejudice against gay men.

    PubMed

    Lai, Calvin K; Haidt, Jonathan; Nosek, Brian A

    2014-01-01

    Disgust is linked to social evaluation. People with higher disgust sensitivity exhibit more sexual prejudice, and inducing disgust increases sexual prejudice. We tested whether inducing moral elevation, the theoretical opposite of disgust, would reduce sexual prejudice. In four studies (N = 3622), we induced elevation with inspiring videos and then measured sexual prejudice with implicit and explicit measures. Compared to control videos that elicited no particular affective state, we found that elevation reduced implicit and explicit sexual prejudice, albeit very slightly. No effect was observed when the target of social evaluation was changed to race (Black-White). Inducing amusement, another positive emotion, did not significantly affect sexual prejudice. We conclude that elevation weakly but reliably reduces prejudice towards gay men.

  12. Infrared photoemitting diode having reduced work function

    DOEpatents

    Hirschfeld, Tomas B.

    1984-01-01

    In electro-optical detectors which include as elements a photoemitting photocathode and anode, a photoemitting diode is fabricated which lowers the diode's work function, thus reducing the cooling requirement typically needed for this type of device. The work function is reduced by sandwiching between the photocathode and anode a liquid medium of the formula NR.sub.3 and having an electron affinity for the electrons of the photocathode, which liquid medium permits free electrons leaving the photocathode to remain as stable solvated species in the liquid medium. Thus, highly light-absorbent, and therefore thin, metallic layers can be used for detection, thereby reducing dark current at a given temperature, with a consequent reduction in cooling requirements at constant detector performance.

  13. Infrared photoemitting diode having reduced work function

    DOEpatents

    Hirschfeld, T.B.

    1982-05-06

    In electro-optical detectors which include as elements a photoemitting photocathode and anode, a photoemitting diode is fabricated which lowers the diode's work function, thus reducing the cooling requirement typically needed for this type of device. The work function is reduced by sandwiching between the photocathode and anode a liquid meidum of the formula NR/sub 3/ and having an electron affinity for the electrons of the photocathode, which liquid medium permits free electrons leaving the photocathode to remain as stable solvated species in the liquid medium. Thus, highly light-absorbent, and therefore thin, metallic layers can be used for detection, thereby reducing dark current at a given temperature, with a consequent reduction in cooling requirements at constant detector performance.

  14. Process for reducing beta activity in uranium

    DOEpatents

    Briggs, Gifford G.; Kato, Takeo R.; Schonegg, Edward

    1986-10-07

    This invention is a method for lowering the beta radiation hazards associated with the casting of uranium. The method reduces the beta radiation emitted from the as-cast surfaces of uranium ingots. The method also reduces the amount of beta radiation emitters retained on the interiors of the crucibles that have been used to melt the uranium charges and which have undergone cleaning in a remote handling facility. The lowering of the radioactivity is done by scavenging the beta emitters from the molten uranium with a molten mixture containing the fluorides of magnesium and calcium. The method provides a means of collection and disposal of the beta emitters in a manner that reduces radiation exposure to operating personnel in the work area where the ingots are cast and processed.

  15. Process for reducing beta activity in uranium

    DOEpatents

    Briggs, Gifford G.; Kato, Takeo R.; Schonegg, Edward

    1986-01-01

    This invention is a method for lowering the beta radiation hazards associated with the casting of uranium. The method reduces the beta radiation emitted from the as-cast surfaces of uranium ingots. The method also reduces the amount of beta radiation emitters retained on the interiors of the crucibles that have been used to melt the uranium charges and which have undergone cleaning in a remote handling facility. The lowering of the radioactivity is done by scavenging the beta emitters from the molten uranium with a molten mixture containing the fluorides of magnesium and calcium. The method provides a means of collection and disposal of the beta emitters in a manner that reduces radiation exposure to operating personnel in the work area where the ingots are cast and processed.

  16. Process for reducing beta activity in uranium

    DOEpatents

    Briggs, G.G.; Kato, T.R.; Schonegg, E.

    1985-04-11

    This invention is a method for lowering the beta radiation hazards associated with the casting of uranium. The method reduces the beta radiation emitted from the as-cast surfaces of uranium ingots. The method also reduces the amount of beta radiation emitters retained on the interiors of the crucibles that have been used to melt the uranium charges and which undergone cleaning in a remote handling facility. The lowering of the radioactivity is done by scavenging the beta emitters from the molten uranium with a molten mixture containing the fluorides of magnesium and calcium. The method provides a means of collection and disposal of the beta emitters in a manner that reduces radiation exposure to operating personnel in the work area where the ingots are cast and processed. 5 tabs.

  17. Reduced-energy decoding of MPEG streams

    NASA Astrophysics Data System (ADS)

    Mesarina, Melena; Turner, Yoshio

    2001-12-01

    Long battery life and high performance multimedia decoding are competing design goals for portable appliances. For a target level of QoS, the achievable battery life can be increased by dynamically adjusting the supply voltage throughout execution. In this paper, an efficient offline scheduling algorithm is proposed for preprocessing stored MPEG audio and video streams. It computes the order and voltage settings at which the appliance's CPU decodes the frames, reducing energy consumption without violating timing or buffering constraints. Our experimental results elucidate the tradeoff of QoS and energy consumption. They demonstrate that the scheduler reduces CPU energy consumption by 19%, without any sacrifice of quality, and by nearly 50%, with only slightly reduced quality. The results also explore how the QoS/energy tradeoff is affected by buffering and processor speed.

  18. Arbuscular mycorrhizas reduce nitrogen loss via leaching.

    PubMed

    Asghari, Hamid R; Cavagnaro, Timothy R

    2012-01-01

    The capacity of mycorrhizal and non-mycorrhizal root systems to reduce nitrate (NO₃⁻) and ammonium (NH₄⁺) loss from soils via leaching was investigated in a microcosm-based study. A mycorrhiza defective tomato mutant and its mycorrhizal wildtype progenitor were used in this experiment in order to avoid the indirect effects of establishing non-mycorrhizal control treatments on soil nitrogen cycling and the wider soil biota. Mycorrhizal root systems dramatically reduced nitrate loss (almost 40 times less) via leaching, compared to their non-mycorrhizal counterparts, following a pulse application of ammonium nitrate to experimental microcosms. The capacity of AM to reduce nutrient loss via leaching has received relatively little attention, but as demonstrated here, can be significant. Taken together, these data highlight the need to consider the potential benefits of AM beyond improvements in plant nutrition alone.

  19. Reducing online identity disclosure using warnings.

    PubMed

    Carpenter, Sandra; Zhu, Feng; Kolimi, Swapna

    2014-09-01

    In an experimental design, we tested whether written warnings can reduce the amount of identity information exposure online. A psychological attack on information privacy that has been shown to be effective in previous research was launched. This attack took advantage of the fact that people respond to certain types of requests in a relatively automatic, or mindless, fashion. The experiment manipulated the word that was used in the alert header: "warning", "caution", or "hazard". All warnings proved to be effective in reducing disclosure, but "hazard" proved to be most effective. Also warnings were more effective in reducing disclosure of driver's license numbers than email addresses. The discussion (a) provides tentative conclusions why these patterns were obtained, (b) suggests how to design warnings in cyber-environments, and (c) addresses future possibilities for research on this topic.

  20. Study examines sulfate-reducing bacteria activity

    SciTech Connect

    McElhiney, J.E.; Hardy, J.A.; Rizk, T.Y.; Stott, J.F.D.; Eden, R.D.

    1996-12-09

    Low-sulfate seawater injection can reduce the potential of an oil reservoir turning sour because of sulfate-reducing bacteria. Sulfate-reducing bacteria (SRB) convert sulfate ions in seawater used in waterflooding into sulfide with the concomitant oxidation of a carbon source. A recent study at Capcis investigated the efficiency of SRB under various conditions of sulfate limitation. This study was conducted in a flowing bioreactor at 2,000 psia with different temperature zones (mesophilic 35 C and thermophilic 60--80 C). The study mixed microfloral populations derived from real North Sea-produced fluids, and included an active population of marine methanogenic bacteria present to provide competition for the available carbon sources. In general, results showed that SRB continue to convert sulfate to sulfide in stoichiometric quantities without regard to absolute concentrations. The paper discusses the results and recommends nanofiltration of seawater for ``sweet`` reservoirs.

  1. Nature of Reduced Carbon in Martian Meteorites

    NASA Technical Reports Server (NTRS)

    Gibson, Everett K., Jr.; McKay, D. S.; Thomas-Keprta, K. L.; Clemett, S. J.; White, L. M.

    2012-01-01

    Martian meteorites provide important information on the nature of reduced carbon components present on Mars throughout its history. The first in situ analyses for carbon on the surface of Mars by the Viking landers yielded disappointing results. With the recognition of Martian meteorites on Earth, investigations have shown carbon-bearing phases exist on Mars. Studies have yielded presence of reduced carbon, carbonates and inferred graphitic carbon phases. Samples ranging in age from the first approximately 4 Ga of Mars history [e.g. ALH84001] to nakhlites with a crystallization age of 1.3 Ga [e.g. Nakhla] with aqueous alteration processes occurring 0.5-0.7 Ga after crystallizaton. Shergottites demonstrate formation ages around 165-500 Ma with younger aqueous alterations events. Only a limited number of the Martian meteorites do not show evidence of significance terrestrial alterations. Selected areas within ALH84001, Nakhla, Yamato 000593 and possibly Tissint are suitable for study of their indigenous reduced carbon bearing phases. Nakhla possesses discrete, well-defined carbonaceous phases present within iddingsite alteration zones. Based upon both isotopic measurements and analysis of Nakhla's organic phases the presence of pre-terrestrial organics is now recognized. The reduced carbon-bearing phases appear to have been deposited during preterrestrial aqueous alteration events that produced clays. In addition, the microcrystalline layers of Nakhla's iddingsite have discrete units of salt crystals suggestive of evaporation processes. While we can only speculate on the origin of these unique carbonaceous structures, we note that the significance of such observations is that it may allow us to understand the role of Martian carbon as seen in the Martian meteorites with obvious implications for astrobiology and the pre-biotic evolution of Mars. In any case, our observations strongly suggest that reduced organic carbon exists as micrometer- size, discrete structures

  2. Stress, burnout, and strategies for reducing them

    PubMed Central

    Lee, F. Joseph; Stewart, Moira; Brown, Judith Belle

    2008-01-01

    OBJECTIVE To ascertain Canadian family physicians’ levels of stress and burnout and the strategies they use to reduce these problems. DESIGN Census survey. SETTING Kitchener-Waterloo, an urban area with a population of approximately 300 000 in southwestern Ontario. PARTICIPANTS Family physicians. MAIN OUTCOME MEASURES Scores on the Family Physician Stress Inventory, scores on strategies to reduce personal stress, scores on strategies to reduce stress on the job, and scores on the Maslach Burnout Inventory. RESULTS Participation rate was 77.8% (123 of 158 surveys returned). About 42.5% of participants had high stress levels. Burnout was defined by 3 components: emotional exhaustion, depersonalization (going through the day like an “automaton”), and perceived lack of personal accomplishment. Many respondents scored high on the burnout inventory, and almost half had high levels of emotional exhaustion and depersonalization (47.9% and 46.3%, respectively). No demographic factors were associated with high scores on these components. Use of strategies to reduce personal and occupational stress was associated with lower levels of burnout. Scores on the Family Physician Stress Inventory correlated highly with scores on the Maslach Burnout Inventory. CONCLUSION Regardless of demographic factors, family physicians are at risk of having high levels of stress and burnout. Classic burnout is related to stress brought on by factors such as too much paperwork, long waits for specialists and tests, feeling undervalued, feeling unsupported, and having to abide by rules and regulations. Common strategies for reducing personal stress included eating nutritiously and spending time with family and friends. Common strategies for reducing stress on the job included valuing relationships with patients and participating in continuing medical education. Stress and burnout are related to the desire to give up practice and are, therefore, a human resources issue for the entire health

  3. Reducing the capacitance of piezoelectric film sensors.

    PubMed

    González, Martín G; Sorichetti, Patricio A; Santiago, Guillermo D

    2016-04-01

    We present a novel design for large area, wideband, polymer piezoelectric sensor with low capacitance. The large area allows better spatial resolution in applications such as photoacoustic tomography and the reduced capacitance eases the design of fast transimpedance amplifiers. The metalized piezoelectric polymer thin film is segmented into N sections, electrically connected in series. In this way, the total capacitance is reduced by a factor 1/N(2), whereas the mechanical response and the active area of the sensor are not modified. We show the construction details for a two-section sensor, together with the impedance spectroscopy and impulse response experimental results that validate the design.

  4. A Review of Focal Reducer Interferometer Systems

    DTIC Science & Technology

    1986-06-01

    searches. G.Courtes has also proposed a design for a focal reducer for the E.S.O. 3.6m. Ritchey -Chretien telescope (Fig. 4b). He uses a Schmidt camera...spaced components, with a modified Wynne camera design (Fig. 7). The instrument proposed used folded optics and would operate at the F/8 Ritchey Cretien ...G.Courtes for the 3.6m Ritchey Chretien telescope . a, telescope focal plane and field lens; b, collimator; c, camera. Figure 5 The focal reducer of A.B

  5. Viscous damped space structure for reduced jitter

    NASA Technical Reports Server (NTRS)

    Wilson, James F.; Davis, L. Porter

    1987-01-01

    A technique to provide modal vibration damping in high performance space structures was developed which uses less than one once of incompressible fluid. Up to 50 percent damping can be achieved which can reduce the settling times of the lowest structural mode by as much as 50 to 1. This concept allows the designers to reduce the weight of the structure while improving its dynamic performance. Damping by this technique is purely viscous and has been shown by test to be linear over 5 orders of input magnitude. Amplitudes as low as 0.2 microinch were demonstrated. Damping in the system is independent of stiffness and relatively insensitive to temperature.

  6. Vacancy ordering in reduced barium titanate

    NASA Astrophysics Data System (ADS)

    Woodward, David I.; Reaney, Ian M.; Yang, Gaiying Y.; Dickey, Elizabeth C.; Randall, Clive A.

    2004-06-01

    A crystal structure is proposed for reduced barium titanate, BaTiO3-δ, δ≈0.33, formed during the degradation of Ni-BaTiO3 X7R multilayer ceramic capacitors. High-resolution transmission electron microscopy and selected-area electron diffraction have been used in combination with computer simulations to show that oxygen vacancies accrete on every third pseudocubic {111} plane, resulting in a cell with space group P3m1. Additionally, from electron energy loss spectroscopy, it is proposed that Ti4+ is reduced to Ti3+ as a mechanism of charge compensation within oxygen-deficient octahedra.

  7. Natural genetic variability reduces recalcitrance in poplar

    SciTech Connect

    Bhagia, Samarthya; Muchero, Wellington; Kumar, Rajeev; Tuskan, Gerald A.; Wyman, Charles E.

    2016-05-20

    Here, lignin content and structure are known to affect recalcitrance of lignocellulosic biomass to chemical/biochemical conversion. Previously, we identified rare Populus trichocarpa natural variants with significantly reduced lignin content. Because reduced lignin content may lower recalcitrance, 18 rare variants along with 4 comparators, and BESC standard Populus was analyzed for composition of structural carbohydrates and lignin. Sugar yields from these plants were measured at 5 process conditions: one for just enzymatic hydrolysis without pretreatment and four via our combined high-throughput hot water pretreatment and co-hydrolysis (HTPH) technique.

  8. Natural genetic variability reduces recalcitrance in poplar

    DOE PAGES

    Bhagia, Samarthya; Muchero, Wellington; Kumar, Rajeev; ...

    2016-05-20

    Here, lignin content and structure are known to affect recalcitrance of lignocellulosic biomass to chemical/biochemical conversion. Previously, we identified rare Populus trichocarpa natural variants with significantly reduced lignin content. Because reduced lignin content may lower recalcitrance, 18 rare variants along with 4 comparators, and BESC standard Populus was analyzed for composition of structural carbohydrates and lignin. Sugar yields from these plants were measured at 5 process conditions: one for just enzymatic hydrolysis without pretreatment and four via our combined high-throughput hot water pretreatment and co-hydrolysis (HTPH) technique.

  9. Reduced Basis Method for Nanodevices Simulation

    SciTech Connect

    Pau, George Shu Heng

    2008-05-23

    Ballistic transport simulation in nanodevices, which involves self-consistently solving a coupled Schrodinger-Poisson system of equations, is usually computationally intensive. Here, we propose coupling the reduced basis method with the subband decomposition method to improve the overall efficiency of the simulation. By exploiting a posteriori error estimation procedure and greedy sampling algorithm, we are able to design an algorithm where the computational cost is reduced significantly. In addition, the computational cost only grows marginally with the number of grid points in the confined direction.

  10. A reduced gravity fiber pulling apparatus

    NASA Technical Reports Server (NTRS)

    Tucker, D. S.

    1992-01-01

    A reduced gravity fiber pulling apparatus (FPA) was constructed in order to study the effects of gravity on glass fiber formation. The apparatus was specifically designed and built for use on NASA's KC-135 aircraft. To date, four flights have been completed during which E-glass fiber was successfully produced in simulated lunar gravity.

  11. Light gas gun with reduced timing jitter

    DOEpatents

    Laabs, G.W.; Funk, D.J.; Asay, B.W.

    1998-06-09

    Gas gun with reduced timing jitter is disclosed. A gas gun having a prepressurized projectile held in place with a glass rod in compression is described. The glass rod is destroyed with an explosive at a precise time which allows a restraining pin to be moved and free the projectile. 4 figs.

  12. Light gas gun with reduced timing jitter

    DOEpatents

    Laabs, Gary W.; Funk, David J.; Asay, Blaine W.

    1998-01-01

    Gas gun with reduced timing jitter. A gas gun having a prepressurized projectile held in place with a glass rod in compression is described. The glass rod is destroyed with an explosive at a precise time which allows a restraining pin to be moved and free the projectile.

  13. Reducing the diameters of computer networks

    NASA Technical Reports Server (NTRS)

    Bokhari, S. H.; Raza, A. D.

    1986-01-01

    Three methods of reducing the diameters of computer networks by adding additional processor to processor links under the constraint that no more than one I/O port be added to each processor are discussed. This is equivalent to adding edges to a given graph under the constraint that the degree of any node be increased, at most, by one.

  14. 21 CFR 582.5375 - Iron reduced.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Iron reduced. 582.5375 Section 582.5375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  15. 21 CFR 582.5375 - Iron reduced.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Iron reduced. 582.5375 Section 582.5375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  16. 21 CFR 582.5375 - Iron reduced.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Iron reduced. 582.5375 Section 582.5375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  17. 21 CFR 582.5375 - Iron reduced.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Iron reduced. 582.5375 Section 582.5375 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) ANIMAL DRUGS, FEEDS, AND RELATED PRODUCTS SUBSTANCES GENERALLY RECOGNIZED AS SAFE Nutrients and/or Dietary...

  18. Reducing Heating In High-Speed Cinematography

    NASA Technical Reports Server (NTRS)

    Slater, Howard A.

    1989-01-01

    Infrared-absorbing and infrared-reflecting glass filters simple and effective means for reducing rise in temperature during high-speed motion-picture photography. "Hot-mirror" and "cold-mirror" configurations, employed in projection of images, helps prevent excessive heating of scenes by powerful lamps used in high-speed photography.

  19. Reducing Error in Mail Surveys. ERIC Digest.

    ERIC Educational Resources Information Center

    Cui, Weiwei

    This Digest describes four types of errors in mail surveys and summarizes the ways they can be reduced. Any one of these sources of error can make survey results unacceptable. Sampling error is examined through inferential statistics applied to sample survey results. In general, increasing sample size will decrease sampling error when simple…

  20. Fluidized-bed combustion reduces atmospheric pollutants

    NASA Technical Reports Server (NTRS)

    Jonke, A. A.

    1972-01-01

    Method of reducing sulfur and nitrogen oxides released during combustion of fossil fuels is described. Fuel is burned in fluidized bed of solids with simultaneous feeding of crushed or pulverized limestone to control emission. Process also offers high heat transfer rates and efficient contacting for gas-solid reactions.

  1. Reducing sucrose loss in sugarbeet storage

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Sucrose loss in sugarbeet storage is a considerable problem which is negatively influenced by environmental conditions, stress on roots from disease problems in the field, rough handling during harvest and transport, and microbial growth. To reduce sucrose loss in sugarbeet storage, studies were in...

  2. Reducible cationic lipids for gene transfer.

    PubMed Central

    Wetzer, B; Byk, G; Frederic, M; Airiau, M; Blanche, F; Pitard, B; Scherman, D

    2001-01-01

    One of the main challenges of gene therapy remains the increase of gene delivery into eukaryotic cells. We tested whether intracellular DNA release, an essential step for gene transfer, could be facilitated by using reducible cationic DNA-delivery vectors. For this purpose, plasmid DNA was complexed with cationic lipids bearing a disulphide bond. This reduction-sensitive linker is expected to be reduced and cleaved in the reducing milieu of the cytoplasm, thus potentially improving DNA release and consequently transfection. The DNA--disulphide-lipid complexation was monitored by ethidium bromide exclusion, and the size of complexes was determined by dynamic light scattering. It was found that the reduction kinetics of disulphide groups in DNA--lipid complexes depended on the position of the disulphide linker within the lipid molecule. Furthermore, the internal structure of DNA--lipid particles was examined by small-angle X-ray scattering before and after lipid reduction. DNA release from lipid complexes was observed after the reduction of disulphide bonds of several lipids. Cell-transfection experiments suggested that complexes formed with selected reducible lipids resulted in up to 1000-fold higher reporter-gene activity, when compared with their analogues without disulphide bonds. In conclusion, reduction-sensitive groups introduced into cationic lipid backbones potentially allow enhanced DNA release from DNA--lipid complexes after intracellular reduction and represent a tool for improved vectorization. PMID:11389682

  3. Reducible cationic lipids for gene transfer.

    PubMed

    Wetzer, B; Byk, G; Frederic, M; Airiau, M; Blanche, F; Pitard, B; Scherman, D

    2001-06-15

    One of the main challenges of gene therapy remains the increase of gene delivery into eukaryotic cells. We tested whether intracellular DNA release, an essential step for gene transfer, could be facilitated by using reducible cationic DNA-delivery vectors. For this purpose, plasmid DNA was complexed with cationic lipids bearing a disulphide bond. This reduction-sensitive linker is expected to be reduced and cleaved in the reducing milieu of the cytoplasm, thus potentially improving DNA release and consequently transfection. The DNA--disulphide-lipid complexation was monitored by ethidium bromide exclusion, and the size of complexes was determined by dynamic light scattering. It was found that the reduction kinetics of disulphide groups in DNA--lipid complexes depended on the position of the disulphide linker within the lipid molecule. Furthermore, the internal structure of DNA--lipid particles was examined by small-angle X-ray scattering before and after lipid reduction. DNA release from lipid complexes was observed after the reduction of disulphide bonds of several lipids. Cell-transfection experiments suggested that complexes formed with selected reducible lipids resulted in up to 1000-fold higher reporter-gene activity, when compared with their analogues without disulphide bonds. In conclusion, reduction-sensitive groups introduced into cationic lipid backbones potentially allow enhanced DNA release from DNA--lipid complexes after intracellular reduction and represent a tool for improved vectorization.

  4. Reducing Skin Picking via Competing Activities

    ERIC Educational Resources Information Center

    Lane, Kathleen Lynne; Thompson, Ada; Reske, Cara L.; Gable, Lauren M.; Barton-Arwood, Sally

    2006-01-01

    This study examined the outcomes of a competing activities intervention to decrease skin picking exhibited by a 9-year-old student with comorbid diagnoses. Results of an ABCBAB design revealed that the use of student-selected manipulatives resulted in reduced skin picking. (Contains 1 figure.)

  5. Reducing Adverse Impact: One City's Efforts.

    ERIC Educational Resources Information Center

    Prewitt, Jeff

    Following a workshop on "Innovations in Employment Testing that Improve Validity and Reduce Adverse Impact," the City of Louisville (Kentucky) implemented a strategy to develop a comprehensive testing and recruiting program for police recruits. To improve candidate expectations and preparation, the following activities were undertaken:…

  6. Reflecting layers reduce weight of insulation

    NASA Technical Reports Server (NTRS)

    Cole, J. D.; Schlessinger, E. D.; Rockoff, H. J.

    1981-01-01

    Metalized films placed between layers of fibrous material maintain equivalent thermal conductivity while cutting blanket density in half. Tests indicate that insulation with 1 lb/cu ft density with goldized films has thermal conductivity equal to 2 lb/cu ft of conventional insulation. Concept reduces weight in commercial aircraft and increases cargo space.

  7. Reducing Class Size: Promises and Perils

    ERIC Educational Resources Information Center

    Bascia, Nina; Fredua-Kwarteng, Eric

    2008-01-01

    Reducing class size, especially in primary grades, can have tremendous academic and social benefits for children--benefits that endure well beyond those first years of school. But smaller class sizes are not a cure-all. Beyond the hoopla of enthusiasm for this seemingly simple change in educational practice lie serious consequences for students…

  8. A reduced volumetric expansion factor plot

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.

    1979-01-01

    A reduced volumetric expansion factor plot was constructed for simple fluids which is suitable for engineering computations in heat transfer. Volumetric expansion factors were found useful in correlating heat transfer data over a wide range of operating conditions including liquids, gases and the near critical region.

  9. A reduced volumetric expansion factor plot

    NASA Technical Reports Server (NTRS)

    Hendricks, R. C.

    1979-01-01

    A reduced volumetric expansion factor plot has been constructed for simple fluids which is suitable for engineering computations in heat transfer. Volumetric expansion factors have been found useful in correlating heat transfer data over a wide range of operating conditions including liquids, gases and the near critical region.

  10. Projection screen having reduced ambient light scattering

    DOEpatents

    Sweatt, William C.

    2010-05-11

    An apparatus and method for improving the contrast between incident projected light and ambient light reflected from a projection screen are described. The efficiency of the projection screen for reflection of the projected light remains high, while permitting the projection screen to be utilized in a brightly lighted room. Light power requirements from the projection system utilized may be reduced.

  11. Reducing Alcohol Consumption through Television Advertising.

    ERIC Educational Resources Information Center

    Barber, James G.; And Others

    1989-01-01

    Assessed impact of television commercial based on controlled-drinking principles. Measures were taken 12 months prior to start of campaign and 3 weeks after campaign from regular drinkers of general public whose drinking behavior was known to be unaffected by previous antidrug advertising campaign. Found that advertisement reduced intake provided…

  12. A Health Plan to Reduce Poverty

    ERIC Educational Resources Information Center

    Weil, Alan

    2007-01-01

    Noting that the failures of the U.S. health care system are compounding the problems faced by low-income Americans, Alan Weil argues that any strategy to reduce poverty must provide access to health care for all low-income families. Although nearly all children in families with incomes under 200 percent of poverty are eligible for either Medicaid…

  13. Reducing Depression in Pregnancy: Designing Multimodel Interventions.

    ERIC Educational Resources Information Center

    Cunningham, Maddy; Zayas, Luis H.

    2002-01-01

    High levels of stress on low-income, inner-city women from ethnic minority groups often causes both poor maternal functioning and infant development outcomes. This article reviews literature that proposes using several social work treatment options instead a single approach to reduce maternal depression, expand mothers' social networks, and…

  14. Speak Up: Reduce Your Risk of Falling

    MedlinePlus

    ... sluggish or confused. Ask how to reduce these side effects or if you can take another medicine. The goal of the Speak Up ™ program is to help patients and their advocates become more informed and involved in their health care.

  15. Reducing Research Anxiety among MSW Students

    ERIC Educational Resources Information Center

    Einbinder, Susan Dana

    2014-01-01

    Research anxiety significantly declined in a diverse sample of 59 MSW students in their first-year hybrid online research course in which the instructor used an array of innovative educational techniques empirically proven to reduce this phenomenon. The pretest/posttest study, the standardized survey instruments used, and a summary of these…

  16. Sodium Valproate Withdrawal Correlates with Reduced Aggression

    ERIC Educational Resources Information Center

    Pritchard, Duncan; Hoerger, Marguerite; Dyer, Tim; Graham, Nicola; Penney, Heather; Mace, F. Charles

    2014-01-01

    People with learning disabilities are sometimes prescribed psychotropic medication to help manage their challenging behaviour. This case study describes how a multicomponent behavioural intervention in conjunction with the systematic withdrawal of sodium valproate was strongly correlated with reduced aggression. No symptoms of bipolar disorder or…

  17. Microwave Oscillator Would Have Reduced Phase Noise

    NASA Technical Reports Server (NTRS)

    Dick, G. John; Saunders, Jon

    1991-01-01

    Microwave oscillators of proposed new type incorporate suppressed-carrier/negative-feedback feature to reduce phase noise near their carrier frequencies. Concept results in phase noise less than achievable by cryogenically stabilized microwave components or by room-temperature oscillators stabilized by quartz crystals. Implemented in three different versions.

  18. How to reduce your fire insurance rates

    NASA Technical Reports Server (NTRS)

    Dubain, M.

    1971-01-01

    Construction procedures and utilization of materials to reduce the cost of insuring large buildings against losses from fire are discussed. Examples of good and bad techniques in building construction and fire safety management are provided. The inadequacies of building codes and the hazards resulting from improper construction are examined.

  19. How Does Distinctive Processing Reduce False Recall?

    ERIC Educational Resources Information Center

    Hunt, R. Reed; Smith, Rebekah E.; Dunlap, Kathryn R.

    2011-01-01

    False memories arising from associatively related lists are a robust phenomenon that resists many efforts to prevent it. However, a few variables have been shown to reduce this form of false memory. Explanations for how the reduction is accomplished have focused on either output monitoring processes or constraints on access, but neither idea alone…

  20. Using Technology To Reduce Public School Violence.

    ERIC Educational Resources Information Center

    Brown, John A.; Brown, Robert C.; Ledford, Bruce R.

    1996-01-01

    Describes technology-driven strategies for reducing school violence: (1) commitment communicated by newsletters and cable television; (2) elimination of weapons using metal detectors, surveillance cameras, breathalyzers, student passes, alarm systems, and school emergency plans; (3) two-way communications and low technology; (4) educational…