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Sample records for 2-glucocide reduces micronucleus

  1. Micronucleus assay in aquatic animals.

    PubMed

    Bolognesi, Claudia; Hayashi, Makoto

    2011-01-01

    Aquatic pollutants produce multiple consequences at organism, population, community and ecosystem level, affecting organ function, reproductive status, population size, species survival and thus biodiversity. Among these, carcinogenic and mutagenic compounds are the most dangerous as their effects may exert a damage beyond that of individual and may be active through several generations. The application of genotoxicity biomarkers in sentinel organisms allows for the assessment of mutagenic hazards and/or for the identification of the sources and fate of the contaminants. Micronucleus (MN) test as an index of accumulated genetic damage during the lifespan of the cells is one of the most suitable techniques to identify integrated response to the complex mixture of contaminants. MN assay is today widely applied in a large number of wild and transplanted aquatic species. The large majority of studies or programmes on the genotoxic effect of the polluted water environment have been carried out with the use of bivalves and fish. Haemocytes and gill cells are the target tissues most frequently considered for the MN determination in bivalves. The MN test was widely validated and was successfully applied in a large number of field studies using bivalves from the genera Mytilus. MN in fish can be visualised in different cell types: erythrocytes and gill, kidney, hepatic and fin cells. The use of peripheral erythrocytes is more widely used because it avoids the complex cell preparation and the killing of the animals. The MN test in fish erythrocytes was validated in laboratory with different species after exposure to a large number of genotoxic agents. The erythrocyte MN test in fish was also widely and frequently applied for genotoxicity assessment of freshwater and marine environment in situ using native or caged animals following different periods of exposure. Large interspecies differences in sensitivity for MN induction were observed. Further validation studies are

  2. Effect of erythropoietin on the micronucleus test.

    PubMed

    Suzuki, Y; Nagae, Y; Ishikawa, T; Watanabe, Y; Nagashima, T; Matsukubo, K; Shimizu, H

    1989-01-01

    The micronucleus test is used widely as an in vivo short-term assay for potential carcinogens. In the present study, results of the micronucleus test were affected by the rate of erythropoiesis in the bone marrow erythropoietin, a growth factor for the erythroblast, which was used to induce erythropoiesis. The highest frequency of micronucleated polychromatic erythrocytes (MPCE) and a dose-response relationship between erythropoietin doses and MPCE frequency were seen 30 hr after injection of 1,1-dimethylhydrazine (DMH) to mice administered 24 hr previously with erythropoietin. The effect of erythropoietin was maximal when erythropoietin was given 24 hr before DMH, indicating that accelerating the multiplication of erythroblasts will increase the frequency of micronuclei induced by mutagens. Induction of MPCE in the bone marrow by four other compounds--benzo(a)pyrene, 2-naphthylamine, mitomycin C, and vincristine--was also increased by pretreatment with erythropoietin. PMID:2737182

  3. Selection of the germinal micronucleus in Paramecium caudatum: nuclear division and nuclear death.

    PubMed

    Taka, Noriko; Kurokawa, Koya; Araki, Takako; Mikami, Kazuyuki

    2006-01-01

    Each cell of Paramecium caudatum has a germinal micronucleus. When a bi-micronucleate state was created artificially by micronuclear transplantation, both micronuclei divided for at least 2 cell cycles after nuclear transplantation. However, this bi-micronucleate state was unstable and reduced to a uni-micronucleate state after several fissions. Although the number of micronuclei was usually 1 during the vegetative phase, 4 presumptive micronuclei differentiated after conjugation. At the first post-conjugational fission, only 1 of the 4 micronuclei divided, indicating that there is tight regulation of micronuclear number in exconjugants. Micronuclei that did not divide at the first post-conjugational fission may persist through the first and second post-conjugational cell cycles. The decision to divide appears to be separate from the decision to degenerate, as evidenced by division of a remaining micronucleus upon removal of the dividing micronucleus at the first division. Degeneration of micronuclei in exconjugants differs from that of haploid nuclei after meiosis. Nutritional state affected micronuclear degeneration. Under well-fed conditions, the micronuclei destined to degenerate lost the ability to divide earlier than after starvation treatment, suggesting that micronuclear degeneration is an "apoptotic" phenomenon, probably under the control of the new macronuclei (macronuclear anlagen). PMID:16677339

  4. 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

  5. Evaluation of eugenol for mutagenicity by the mouse micronucleus test.

    PubMed

    Woolverton, C J; Fotos, P G; Mokas, M J; Mermigas, M E

    1986-09-01

    Mutagenicity of eugenol (2-methoxy-4-allylphenol) was evaluated by an in vivo eukaryotic assay in mice. A 50% lethal dose (LD50) for intraperitoneal (IP) delivery of eugenol was found to be 1109.6 mg/kg body weight (7.5% eugenol-in-saline). Oral (PO) delivery via stainless-steel, esophageal cannulation was not lethal to 14,794 mg/kg body weight (100%) eugenol. Based upon recommended procedure, 80 and 25% LD50 doses were administered IP in 250 microliter volumes. Undiluted eugenol was administered PO in 100 microliter volumes. Delivery of eugenol by both regimes to male mice induced anaphase mutations in polychromatic erythrocytes as measured by the bone marrow micronucleus test. IP delivery of both doses induced the formation of micronuclei to significant levels (P less than 0.001) compared to saline controls. PO delivery of eugenol induced a much reduced frequency of micronuclei when compared to the IP route. However, a significant increase in micronuclei was evident when this test population was compared to its control group (P less than 0.003). These results suggest that eugenol presents some mutagenic capacity in eukaryotic hosts and should be evaluated for further toxicological effects. PMID:3100745

  6. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... develops into a polychromatic erythrocyte, the main nucleus is extruded; any micronucleus that has been... facilitated in these cells because they lack a main nucleus. An increase in the frequency of micronucleated... the poles of the daughter cells. Micronuclei are small nuclei, separate from and additional to...

  7. 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…

  8. A novel micronucleus in vitro assay utilizing human hematopoietic stem cells.

    PubMed

    Kotova, N; Hebert, N; Härnwall, E-L; Vare, D; Mazurier, C; Douay, L; Jenssen, D; Grawé, J

    2015-10-01

    The induction of micronucleated reticulocytes in the bone marrow is a sensitive indicator of chromosomal damage. Therefore, the micronucleus assay in rodents is widely used in genotoxicity and carcinogenicity testing. A test system based on cultured human primary cells could potentially provide better prediction compared to animal tests, increasing patient safety while also implementing the 3Rs principle, i.e. replace, reduce and refine. Hereby, we describe the development of an in vitro micronucleus assay based on animal-free ex vivo culture of human red blood cells from hematopoietic stem cells. To validate the method, five clastogens with direct action, three clastogens requiring metabolic activation, four aneugenic and three non-genotoxic compounds have been tested. Also, different metabolic systems have been applied. Flow cytometry was used for detection and enumeration of micronuclei. Altogether, the results were in agreement with the published data and indicated that a sensitive and cost effective in vitro assay to assess genotoxicity with a potential to high-throughput screening has been developed. PMID:26208286

  9. Micronucleus formation induced by dielectric barrier discharge plasma exposure in brain cancer cells

    NASA Astrophysics Data System (ADS)

    Kaushik, Nagendra K.; Uhm, Hansup; Ha Choi, Eun

    2012-02-01

    Induction of micronucleus formation (cytogenetic damage) in brain cancer cells upon exposure of dielectric barrier discharge plasma has been investigated. We have investigated the influence of exposure and incubation times on T98G brain cancer cells by using growth kinetic, clonogenic, and micronucleus formation assay. We found that micronucleus formation rate directly depends on the plasma exposure time. It is also shown that colony formation capacity of cells has been inhibited by the treatment of plasma at all doses. Cell death and micronucleus formation are shown to be significantly elevated by 120 and 240 s exposure of dielectric barrier discharge plasma.

  10. 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

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

    PubMed Central

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

    2008-01-01

    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

  12. In vivo rodent erythrocyte micronucleus assay. II. Some aspects of protocol design including repeated treatments, integration with toxicity testing, and automated scoring.

    PubMed

    Hayashi, M; MacGregor, J T; Gatehouse, D G; Adler, I D; Blakey, D H; Dertinger, S D; Krishna, G; Morita, T; Russo, A; Sutou, S

    2000-01-01

    An expert working group on the in vivo micronucleus assay, formed as part of the International Workshop on Genotoxicity Test Procedures (IWGTP), discussed protocols for the conduct of established and proposed micronucleus assays at a meeting held March 25-26, 1999 in Washington, DC, in conjunction with the annual meeting of the Environmental Mutagen Society. The working group reached consensus on a number issues, including: (1) protocols using repeated dosing in mice and rats; (2) integration of the (rodent erythrocyte) micronucleus assay into general toxicology studies; (3) the possible omission of concurrently-treated positive control animals from the assay; (4) automation of micronucleus scoring by flow cytometry or image analysis; (5) criteria for regulatory acceptance; (6) detection of aneuploidy induction in the micronucleus assay; and (7) micronucleus assays in tissues (germ cells, other organs, neonatal tissue) other than bone marrow. This report summarizes the discussions and recommendations of this working group. In the classic rodent erythrocyte assay, treatment schedules using repeated dosing of mice or rats, and integration of assays using such schedules into short-term toxicology studies, were considered acceptable as long as certain study criteria were met. When the micronucleus assay is integrated into ongoing toxicology studies, relatively short-term repeated-dose studies should be used preferentially because there is not yet sufficient data to demonstrate that conservative dose selection in longer term studies (longer than 1 month) does not reduce the sensitivity of the assay. Additional validation data are needed to resolve this point. In studies with mice, either bone marrow or blood was considered acceptable as the tissue for assessing micronucleus induction, provided that the absence of spleen function has been verified in the animal strains used. In studies with rats, the principal endpoint should be the frequency of micronucleated immature

  13. 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. PMID:25892624

  14. Micronucleus analysis in patients with colorectal adenocarcinoma and colorectal polyps

    PubMed Central

    Karaman, Ali; Binici, Doğan Nasır; Kabalar, Mehmet Eşref; Çalıkuşu, Züleyha

    2008-01-01

    AIM: To determine, by counting micronucleus (MN) frequencies, whether chromosomal or DNA damage have an effect on the pathogenesis of early colorectal adenocarcinoma (CRC). METHODS: We analyzed MN frequencies in 21 patients with CRC, 24 patients with colon polyps [10 neoplastic polyps (NP) and 14 non-neoplastic polyps (NNP)] and 20 normal controls. RESULTS: MN frequency was significantly increased in CRC patients and in NP patients compared with controls (3.72 ± 1.34, 3.58 ± 1.21 vs 1.97 ± 0.81, P < 0.001). However, there was no difference in the MN frequency between CRC patients and NP patients (P > 0.05). Similarly, there was no difference in the MN frequency between NNP patients (2.06 ± 0.85) and controls (P > 0.05). CONCLUSION: Our results suggest increased chromosome/DNA instabilities may be associated with the pathogenesis of early CRC. PMID:19058310

  15. 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. PMID:25706087

  16. The in vivo gut micronucleus test detects clastogens and aneugens given by gavage.

    PubMed

    Vanhauwaert, A; Vanparys, P; Kirsch-Volders, M

    2001-01-01

    A general testing battery for pharmaceuticals includes a bacterial gene mutation assay, an in vitro chromosomal aberration or a gene mutation test on mammalian cells and an in vivo test for chromosome/genome mutations. The aim of this study was to determine whether the in vivo mouse gut micronucleus assay could be a more sensitive method to detect direct clastogens and/or aneugens given orally by gavage than the in vivo bone marrow micronucleus assay (which can also detect indirect genotoxins). Two laboratories collaborated in this project, one analysing bone marrow cells and the other analysing gut cells from the same animals. The reference substances tested in this study were colchicine (COL), carbendazim (CAR), tubulazole (TUB) and griseofulvin (GRI), all known aneugens, and 1,2-dimethylhydrazine (DMH), a colon carcinogen with clastogenic activity. For all substances tested, the in vivo gut micronucleus test was as sensitive as or more sensitive than the in vivo bone marrow micronucleus assay: COL and TUB induced micronuclei in both gut and bone marrow cells; DMH, CAR and GRI induced micronuclei only in gut cells. The results show that the micronucleus test on gut cells is able to detect clastogens and aneugens given orally by gavage, some of which were not detected by the bone marrow micronucleus test. PMID:11139597

  17. Micronucleus frequencies in groups receiving external or internal radiation

    PubMed Central

    Özdal, Ayşegül; Erselcan, Taner; Özdemir, Öztürk; Silov, Güler; Erdoğan, Zeynep; Turhal, Özgül

    2016-01-01

    Objective: In the current study, we aimed to explore whether there is alteration between pre- and post-treatment micronucleus (MN) frequencies induced by internal and external ionizing radiation. Materials and Methods: The study enrolled a total of 67 patients including patients admitted to our hospital for treatment of hyperthyroidism (n = 17), scanning with low-dose I-131 (n = 15), and ablative therapy with high-dose I-131 (n = 15) at Department of Nuclear Medicine as well as patients with different diagnoses receiving external radiotherapy with various doses and durations at Department of Radiation Oncology (n = 20). Thirty-two patients who received radioactive iodine and returned for a follow-up visit at 1 month. Results: Considering both pre- and post-treatment MN frequencies of each group, lowest MN frequencies were detected for patients undergoing screening with low-dose I-131, and highest MN frequencies were found in radiotherapy patients. Comparison of pre- and post-treatment MN frequencies among hyperthyroidism, when pre- and post-treatment MN frequencies compared among hyperthyroidism, I-131 whole body scanning, ablation, and radiotherapy patient groups differences between MN frequencies were significant for each group (P < 0.05). Conclusion: Our study showed that MN analysis might be of value in determining chromosome damage that could potentially occur in patients exposed to internal and external radiation. PMID:27385886

  18. Antioxidant properties of raspberry seed extracts on micronucleus distribution in peripheral blood lymphocytes.

    PubMed

    Godevac, Dejan; Tesević, Vele; Vajs, Vlatka; Milosavljević, Slobodan; Stanković, Miroslava

    2009-11-01

    This study addresses in vitro effects of raspberry (Rubus idaeus) seed extracts (RSE) on the frequency of micronuclei. We evaluated the effects of three different extracts (50%, 80%, and 100% methanol) in doses of 1.4, 4.2, and 8.4 microg/mL, per 5 mL culture using cytochalasin-B micronucleus (CBMN) assay in peripheral human lymphocytes. The frequency of MN was scored in binucleated (BN) cells. The nuclear proliferation index was also calculated. The distribution of polyphenolic compounds in RSEs was determined using LC/UV/ESI-TOF MS. The identified 37 compounds comprised flavanol monomers and oligomers, as well as varieties of ellagitannin components. Treatment of lymphocytes with RSEs induced a significant decrease in the frequency of micronuclei by 80%. These results demonstrate that the constituents of RSEs may be important in the prevention of oxidative lymphocyte damage by reactive oxygen species and may also reduce the level of DNA damage. These findings support the potential benefits of polyphenolic compounds from raspberry seeds as efficient antioxidants. PMID:19748543

  19. 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. PMID:25275653

  20. Micronucleus investigation of alcoholic patients with oral carcinomas.

    PubMed

    Ramirez, Andréa; Saldanha, Pedro Henrique

    2002-01-01

    The micronucleus test (MN) is used as an indicator of genotoxic exposition, since it is associated with chromosome aberrations. An increased mutation rate in oral squamous cells, indicated by an increased MN frequency, is also related to the development of oral carcinomas. We evaluated the frequencies of MN and other metanucleated anomalies in the buccal squamous cells of 30 alcoholics with oral or oropharyngeal carcinomas, and compared them to a control group of abstinent health individuals. Microscopic examination was made of 2000 cells per individual from each of three distinct areas of the mouth: around the lesion (A), opposite to the lesion (B) and in the upper gingival-labial gutter (C); C was used as a control region because of low tumor frequency. There was a seven-fold increase in MN frequency in region B, a three-fold increase in region A and a two-fold, though nonsignificant, increase in C; indicating a gradient of frequencies towards carcinogenesis: C --> A --> B. Comparisons of frequencies of various types of metanucleated cells: binucleated, karyorrhexis (KR), karyolysis (KL) and broken egg (BE) in patients and controls showed, with few exceptions, highly significant differences. This gave us a better understanding of the dynamics of this squamous epithelium, supporting a more efficient biomonitor based on these various metanucleated anomalies: the repair index RI=(KL+KR)/(MN+BE). Also, the apparently contradictory results from regression analysis revealed that the MN frequency decreased with age and alcohol consumption, probably because of slow cell proliferation, and consequently led to a loss of homeostasis due to aging. In addition, in the analysis of nonparametric variables only one CAGE question was significant, confirming the effect of alcohol. In conclusion, the MN test and the repair index could be used for monitoring clinical evolution, by means of intra- and inter-individual cellular comparisons, in subjects with healed or surgically

  1. Re-evaluation of the need for multiple sampling times in the mouse bone marrow micronucleus assay: results for DMBA

    SciTech Connect

    Ashby, J.; Mirkova, E.

    1987-01-01

    7,12-dimethylbenzanthracene (DMBA) is confirmed as active in the mouse bone marrow micronucleus assay 24 hr after dosing as corn-oil homogenate via either oral gavage or intraperitoneal (ip) injection. These data are consistent with recent observations made by several investigators. However, when dosed via ip injection as a solution in DMSO, peak activity was evident 48 hr after dosing and a dramatic reduction in erythropoiesis was observed. It is suggested that a maximum of two sampling times is adequate and that, as a consequence, the number of animals employed in the conduct of the test could be reduced with no loss of sensitivity. The present data also suggest that the use of a corn-oil homogenate of insoluble test agents may provide an efficient replacement for the use of ground suspensions or solutions in DMSO.

  2. Application of a sea urchin micronucleus assay to monitoring aquatic pollution: influence of sample osmolality.

    PubMed

    Saotome, Kyoko; Hayashi, Makoto

    2003-01-01

    We have improved our sea urchin micronucleus assay for aquatic samples and used it to evaluate marine pollution. We found that the water samples we had collected for 2 years from the Tokyo bay coast near Tokyo, an industrial megalopolis, were positive due to the water samples being hypo-osmotic rather than to chemical pollutants. The evidence was as follows: (i) the osmolality and salinity of the samples were about half that of sea water; (ii) the micronucleus frequency induced in the water sample decreased to the control level when the osmolality was increased to that of sea water; (iii) artificial sea water diluted with distilled water induced micronuclei dilution-dependently. Since micronucleus induction in the sea urchin assay is influenced by sample osmolality, the osmolality must be adjusted to that of sea water for the assay and osmotic pressure must be considered when evaluating water pollution. PMID:12473738

  3. 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. PMID:27053170

  4. A micronucleus-specific sequence exists in the 5'-upstream region of calmodulin gene in Tetrahymena thermophila.

    PubMed Central

    Katoh, M; Hirono, M; Takemasa, T; Kimura, M; Watanabe, Y

    1993-01-01

    Tetrahymena thermophila possesses a transcriptionally inactive micronucleus and an active macronucleus. Both nuclei are developed from micronucleus-derived germ nuclei during conjugation. Extensive DNA rearrangement and transcriptional activation are known to be involved in macronuclear development, but little has been known about these processes in a particular functional gene. Therefore the micro- and macronuclear genomic DNAs for calmodulin gene were analyzed. A 1,384 bp micronucleus-specific sequence located about 3.5 kb upstream of calmodulin gene has been found, suggesting DNA rearrangement during macronuclear development. The micronucleus-specific sequence had 85% A + T, no extensive ORF, ATTAs at both ends, and two palindromic structures just outside of both ends. Interestingly, the micronucleus-specific sequence included a T-rich tract, T16CT5, in the middle, and a nearly complementary A-rich tract, A5TA10GA5, existed 7 bp upstream from the initiation codon. In addition, there was a 20 bp repetitive sequence TAAT(TAAC)4 about 100 bp upstream of the micronucleus-specific sequence and also in the promoter region of calmodulin gene. Although the functional significance of the micronucleus-specific sequence remains unclear, T16CT5 and TAAT(TAAC)4 elements might exert an influence on transcription of the calmodulin gene. Stringent Southern hybridization revealed that this micronucleus-specific sequence or very similar sequence(s) were abundant in the Tetrahymena micronuclear genome. Images PMID:8506136

  5. High Content Flow Cytometric Micronucleus Scoring Method is Applicable to Attachment Cell Lines

    PubMed Central

    Bryce, Steven M.; Shi, Jing; Nicolette, John; Diehl, Marilyn; Sonders, Paul; Avlasevich, Svetlana; Raja, Sarojini; Bemis, Jeffrey C.; Dertinger, Stephen D.

    2009-01-01

    A flow cytometric method for analyzing suspension cell cultures for micronucleus content has been previously reported [Environ. Molec. Mutagen. 47 (2006) 56–66]. The experiments described herein were undertaken to evaluate the compatibility of this method (In Vitro MicroFlow®) with attachment cells. Initially, CHO-K1 cells were studied in nine independent experiments using mitomycin C and cyclophosphamide. The results demonstrated the effectiveness of the cell processing procedure, and also provided historical control data that were useful for setting criteria for making positive calls. Subsequently, CHO-K1 cells were treated with methyl methanesulfonate, mitomycin C, etoposide, vinblastine sulfate, dexamethasone, and sodium chloride. Whereas the four genotoxicants were each observed to increase micronucleus frequencies, the non-genotoxicants induced no such response up to cytotoxic concentrations. Following this initial work, inter-laboratory transferability was evaluated across three sites using a common cell staining and analysis protocol for CHO-K1 or V79 cells that had been treated with the ten chemicals listed in Annex 3 of the OECD Draft Proposal for a New Guideline 487: In Vitro Mammalian Cell Micronucleus Test. With the exception of benzo[a]pyrene at one site, each laboratory observed increased micronucleus frequencies for the genotoxicants, whereas no significant induction occurred with the non-genotoxicants. Interestingly, the method appeared to distinguish between genotoxic modes of action, as only aneugens increased the average micronucleus fluorescence intensity and the frequency of hypodiploid nuclei. Collectively, these data suggest that flow cytometry is capable of providing reliable micronucleus counts, and that additional information is obtained that appears to discern genotoxic modes of action. PMID:19950402

  6. [Study of the antimutagenic properties of Angelica archangelica by the micronucleus test].

    PubMed

    Salikhova, R A; Dulatova, Sh N; Poroshenko, G G

    1993-04-01

    The antimutagenic activity Angelica archangelica L. water and alcohol extracts thio-tepa against mutagenicity was investigated by the micronucleus test in mouse bone marrow and peripheral blood cells. The reduction of thio-tepa mutagenic activity was more prominent when the extracts were injected 2-hours before thio-tepa treatment as it could be seen at the simultaneous treatment. The observed reduction of micronucleus frequencies was up to 77%. No genotoxic effects of Angelica extracts had been seen at the concentrations 50-100 mg/kg. PMID:8049396

  7. Micronucleus formation in human keratinocytes is dependent on radiation quality and tissue architecture.

    PubMed

    Snijders, Antoine M; Mannion, Brandon J; Leung, Stanley G; Moon, Sol C; Kronenberg, Amy; Wiese, Claudia

    2015-01-01

    The cytokinesis-block micronucleus (MN) assay was used to assess the genotoxicity of low doses of different types of space radiation. Normal human primary keratinocytes and immortalized keratinocytes grown in 2D monolayers each were exposed to graded doses of 0.3 or 1.0 GeV/n silicon ions or similar energies of iron ions. The frequencies of induced MN were determined and compared to γ-ray data. RBE(max) values ranged from 1.6 to 3.9 for primary keratinocytes and from 2.4 to 6.3 for immortalized keratinocytes. At low radiation doses ≤ 0.4 Gy, 0.3 GeV/n iron ions were the most effective at inducing MN in normal keratinocytes. An "over-kill effect" was observed for 0.3 GeV/n iron ions at higher doses, wherein 1.0 GeV/n iron ions were most efficient in inducing MN. In immortalized keratinocytes, 0.3 GeV/n iron ions produced MN with greater frequency than 1.0 GeV/n iron ions, except at the highest dose tested. MN formation was higher in immortalized keratinocytes than in normal keratinocytes for all doses and radiation qualities investigated. MN induction was also assessed in human keratinocytes cultured in 3D to simulate the complex architecture of human skin. RBE values for MN formation in 3D were reduced for normal keratinocytes exposed to iron ions, but were elevated for immortalized keratinocytes. Overall, MN induction was significantly lower in keratinocytes cultured in 3D than in 2D. Together, the results suggest that tissue architecture and immortalization status modulate the genotoxic response to space radiation, perhaps via alterations in DNA repair fidelity. PMID:25041929

  8. Micronucleus test and erythropoiesis: effect of cobalt on the induction of micronuclei by mutagens.

    PubMed

    Suzuki, Y; Shimizu, H; Nagae, Y; Fukumoto, M; Okonogi, H; Kadokura, M

    1993-01-01

    The micronucleus test is used widely as an in vivo short-term assay for potential carcinogens. In the present study, results of the micronucleus test were affected by cobalt dichloride pretreatment. Cobalt dichloride was used to induce erythropoietin, a growth factor for erythropoiesis. The increase in mutagen-induced micronucleus response following cobalt pretreatment, therefore, may have been due to a change in the rate of erythropoiesis. The greatest interaction between cobalt pretreatment and mutagen treatment for the induction of micronucleated polychromatic erythrocytes (MPCE) occurred when mice were injected with 1,1-dimethylhydrazine (DMH) 12-24 hr after pretreatment with cobalt dichloride and killed 30 hr later. Increased sensitivity of the micronucleus test was attributable to the administration of mutagen during the differentiation and multiplication of erythroblast, which is presumed to have been accelerated by pretreatment with cobalt dichloride. An increased induction of MPCE in the bone marrow by two chemicals--benzo(a)pyrene, 2-naphthylamine--was also observed following pretreatment with cobalt dichloride. PMID:8359151

  9. 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. PMID:25263003

  10. 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

  11. 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...

  12. 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

    2016-01-01

    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

  13. SPERMATID MICRONUCLEUS ANALYSES OF TRICHLOROETHYLENE AND CHLORAL HYDRATE EFFECTS IN MICE

    EPA Science Inventory

    Mice were exposed by inhalation to trichloroethylene (TCE), or by i.p. injection to the TCE metabolite, chloral hydrate (CH). arly spermatids were analyzed for micronucleus (MN) frequency and kinetochore status (presence or absence) using fluorochrome-labeled anti-kinetochore ant...

  14. 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. PMID:1383722

  15. SOD2-Mediated Effects Induced by WR1065 and Low-Dose Ionizing Radiation on Micronucleus Formation in RKO Human Colon Carcinoma Cells

    PubMed Central

    Murley, Jeffrey S.; Kataoka, Yasushi; Miller, Richard C.; Li, Jian Jian; Woloschak, Gayle; Grdina, David J.

    2010-01-01

    RKO36 cells exposed to either WR1065 or 10 cGy X rays show elevated SOD2 gene expression and SOD2 enzymatic activity. Cells challenged at this time with 2 Gy exhibit enhanced radiation resistance. This phenomenon has been identified as a delayed radioprotective effect or an adaptive response when induced by thiols or low-dose radiation, respectively. In this study we investigated the relative effectiveness of both WR1065 and low-dose radiation in reducing the incidence of radiation-induced micronucleus formation in binucleated RKO36 human colon carcinoma cells. The role of SOD2 in this process was assessed by measuring changes in enzymatic activity as a function of the inducing agent used, the level of protection afforded, and the inhibitory effects of short interfering RNA (SOD2 siRNA). Both WR1065 and 10 cGy X rays effectively induced a greater than threefold elevation in SOD2 activity 24 h after exposure. Cells irradiated at this time with 2 Gy exhibited a significant resistance to micronucleus formation (P < 0.05; Student’s two-tailed t test). This protective effect was significantly inhibited in cells transfected with SOD2 siRNA. SOD2 played an important role in the adaptive/delayed radioprotective response by inhibiting the initiation of a superoxide anion-induced ROS cascade leading to enhanced mitochondrial and nuclear damages. PMID:21175348

  16. 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. PMID:26339413

  17. 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. PMID:25726170

  18. 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. PMID:20338871

  19. Estimation of benchmark dose for micronucleus occurrence in Chinese vinyl chloride-exposed workers☆

    PubMed Central

    Wang, Qi; Tan, Hong-shan; Ma, Xiao-ming; Sun, Yuan; Feng, Nan-nan; Zhou, Li-fang; Ye, Yun-jie; Zhu, Yi-liang; Li, Yong-liang; Brandt-Rauf, Paul W.; Tang, Nai-jun; Xia, Zhao-lin

    2012-01-01

    In this study, we estimated the possibility of using benchmark dose (BMD) to assess the dose–response relationship between vinyl chloride monomer (VCM) exposure and chromosome damage. A group of 317 workers occupationally exposed to vinyl chloride monomer and 166 normal, unexposed control in Shan-dong Province northern China were examined for chromosomal damage in peripheral blood lymphocytes (PBL) using the cytokinesis-blocked micronucleus (CB-MN) assay of DNA damage. The exposed group (3.47 ± 2.65)‰ showed higher micronucleus frequency than the control (1.60 ± 1.30)‰ (P < 0.01). Occupational exposure level based on micronucleus occurrence in all individuals was analyzed with benchmark dose (BMD) methods. The benchmark dose lower limit of a one-sided 95% confidence interval (BMDL) for 10% excess risk was also determined. Results showed a dose–response relationship between cumulative exposure and MN frequency, and a BMDL of 0.54 mg/m3 and 0.23 mg/m3 for males and females, respectively. Female workers were more susceptible to MN damage than male workers. PMID:22425610

  20. Repeated-dose liver and gastrointestinal tract micronucleus assays for quinoline in rats.

    PubMed

    Uno, Fuyumi; Tanaka, Jin; Ueda, Maya; Nagai, Miho; Fukumuro, Masahito; Natsume, Masakatsu; Oba, Michiyo; Akahori, Ayaka; Masumori, Shoji; Takami, Shigeaki; Wako, Yumi; Kawasako, Kazufumi; Kougo, Yuriko; Ohyama, Wakako; Narumi, Kazunori; Fujiishi, Yohei; Okada, Emiko; Hayashi, Makoto

    2015-03-01

    Repeated-dose liver, bone marrow, and gastrointestinal tract micronucleus assays that use young adult rats were evaluated in a collaborative study that was organized by the Japanese Environmental Mutagen Society-Mammalian Mutagenicity Study Group. A genotoxic hepatocarcinogen quinoline was orally administered to independent groups of five Crl:CD (SD) male rats at doses of 30, 60 and 120mg/kg for 14 days and at doses of 15, 30 and 60mg/kg for 28 days. After treatment, the livers were harvested and hepatocytes were isolated by collagenase treatment. The frequency of micronucleated hepatocytes (MNHEPs) increased significantly in both the 14- and 28-day repeated dose studies. However, the frequency of micronucleated cells did not increase in the bone marrow, stomach or colon cells, which were not quinoline-induced carcinogenic target organs in the rats. These results indicate that a repeated-dose liver micronucleus (RDLMN) assay using young adult rats is capable of detecting the genotoxicity of quinoline at the target organ of carcinogenicity. The protocol may also permit the integration of the genotoxic endpoint into general repeated-dose toxicity studies. Furthermore, we elucidated that conducting the micronucleus assay in multiple organs could potentially assess organ specificity. PMID:25892622

  1. 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. PMID:24852491

  2. The genotoxicity study of garlic and pasipy herbal drops by peripheral blood micronucleus test.

    PubMed

    Kalantari, H; Larki, A; Latifi, S M

    2007-09-01

    The in vivo rodent micronucleus test is widely used as a genotoxic assay to detect the clastogenic activity of chemicals. In this research the genotoxic effects of herbal drops of garlic and pasipy were evaluated using the micronucleus test. Maximum Tolerated Dose (MTD) was determined by a dose-response test. For each medicine three treatment groups were considered with doses of MTD, 1/2 MTD and 1/4 MTD according to the CSGMT protocol (1995 Japan). Drugs were administered orally to mice (test groups). Mitomicin C was used as a known genotoxic agent in positive control group. The peripheral blood samples before treatment (zero time samples) were considered as negative control. The appearance of a micronucleus is used as an index for genotoxic potential. The results obtained indicated that the herbal drops showed genotoxicity effect and it was dose-dependent compared to the negative control group. This genotoxicity was significant (p < 0.05) but the genotoxic effects of garlic and pasipy were "not significant" compared to the historical negative control group (p > 0.05). Therefore our results if compared to the negative control group is significant and it is worthy of consideration. PMID:17853777

  3. Role of quercetin on mitomycin C induced genotoxicity: analysis of micronucleus and chromosome aberrations in vivo.

    PubMed

    Mazumdar, Mehnaz; Giri, Sarbani; Giri, Anirudha

    2011-04-01

    Quercetin, a flavonol group of plant flavonoid, has generated immense interest because of its potential antioxidant, anti-proliferative, chemoprotective, anti-inflammatory and gene expression modulating properties. However, the pro-oxidant chemistry of quercetin is important as it is related to the generation of mutagenic quinone-type metabolites. In the present study, 25mg/kg, 50mg/kg and 100mg/kg of quercetin given through the intra peritoneal (i.p.) route induced 2.31 ± 0.27%, 4.72 ± 0.58% and 6.38 ± 0.68% (control value=0.67 ± 0.30%) respectively, of cells with micronucleus (MN) in polychromatic erythrocytes in bone marrow cells and 10.93 ± 0.98%, 10.00 ± 0.89% and 14.27 ± 3.94% (control 2.61 ± 0.48) of cells with chromosome aberrations (CA) following 24h of the treatments. Higher frequencies of MN and CA were also observed after 48h of the treatments. To verify the effect of route of treatment on the quercetin induced damage, 100mg/kg b.w. was given through oral route which declined frequency of MN (P<0.001) as well as CA (P<0.05) as compared to the i.p. route for the same dose. Quercetin also induced higher frequency of metaphases with sticky chromosomes and C-mitosis. Pre-treatment with quercetin significantly reduced the frequency of mitomycin C (MMC) induced MN as well as CA, but no clear correlation between the dose and effect could be observed. Further studies are required to elucidate the possible interaction of quercetin with DNA as well as with other DNA damaging agents like MMC in vivo. The protective action of quercetin was not enhanced when given orally. Our findings suggest that quercetin may result in genomic instability in the tested dose range and significant reduction in MMC induced genotoxicity in the highest dose tested. These effects of quercetin are to be taken into consideration while evaluating the possible use of quercetin as a therapeutic agent. PMID:21256974

  4. Dynamics of changes in micronucleus frequencies in subjects post cessation of chronic low-dose radiation exposure.

    PubMed

    Tsai, M H; Hwang, J S; Chen, K C; Lin, Y P; Hsieh, W A; Chang, W P

    2001-05-01

    To assess DNA damage remaining in peripheral lymphocytes, 48 individuals were evaluated twice for lymphocyte micronucleus frequencies by the cytokinesis-blocking cytochalasin B (CBMN) analysis post relocation from radio-contaminated apartments after various periods of time. The frequencies of CBMN at the first evaluation were significantly higher than those at the second examination (Chang et al., 1999c). These individuals were categorized into three groups: those with cumulative exposure of >300 mSv (defined as high exposure, HDose), those with 100-300 mSv (MDose) and those with <100 mSv (LDose). Using the Poisson mixed-effect model (Little et al., 1996), the estimated mean CBMN frequencies ( per thousand) for individuals in HDose, MDose and LDose exposure categories when they had only recently relocated were 21.8, 17.6 and 15.4, respectively. The estimated mean duration post relocation for the CBMN frequencies of these individuals to reduce to 10.2, the second CBMN frequency, on average, was 47.5, 37.2 and 28.3 months in the three exposure groups, respectively. The rates of change in CBMN frequencies were shown to be significantly higher in the HDose group than in the MDose and LDose groups. The results suggested a characteristic dose-dependent decline in the CBMN frequencies in the exposed population post cessation of chronic low-dose ionizing radiation exposure. PMID:11320151

  5. Tradescantia-micronucleus and -stamen hair mutation assays on genotoxicity of the gaseous and liquid forms of pesticides.

    PubMed

    Mohammed, K B; Ma, T H

    1999-05-19

    The clastogenic and mutagenic effects of the insecticide Dimethoate (Cygon-2E), herbicides Atrazine, Simazine (Princep), Dicamba (Banvel D) and Picloram (Tordon) were studied using the Tradescantia-micronucleus (Trad-MCN) and Tradescantia-stamen hair mutation (Trad-SHM) assays. In clone 4430, dimethoate fumes both significantly increased the pink mutation events and reduced the number of stamen hairs per filament with increasing dosages. The pink mutation events were elevated by the liquid treatment with Picloram at 100 ppm concentration. The result of Trad-MCN test on Dimethoate fumes was not significantly different between the control and treated groups. The herbicide Atrazine showed positive effects at 10-50 ppm dose (liquid) and signs of overdose at 100 and 500 ppm concentrations. Simazine was mildly positive in elevating the MCN frequencies in the dose range of 5 to 200 ppm (liquid doses). Both Dicamba and Picloram induced a dosage-related increase in MCN frequencies in the Trad-MCN tests using Tradescantia clone 03. However, in higher dosages (200 ppm or higher), there were signs of overdose, reduction of MCN frequencies and physical damage of the leaves and buds of plant cuttings. PMID:10350597

  6. Micronucleus frequency and lipid peroxidation in Allium sativum root tip cells treated with gibberellic acid and cadmium.

    PubMed

    Celik, Ayla; Unyayar, Serpil; Cekiç, Fazilet Ozlem; Güzel, Ayşin

    2008-04-01

    Gibberellic acid (GA(3)) is a very potent hormone whose natural occurrence in plants controls their development. Cadmium is a particularly dangerous pollutant due to its high toxicity and great solubility in water. In this study, the effect of GA(3) on Allium sativum root tip cells was investigated in the presence of cadmium. A. sativum root tip cells were exposed to CdNO(3) (50, 100, 200 microM), GA(3) (10-3 M), both CdNO(3) and GA(3). Cytogenetic analyses were performed as micronucleus (MN) assay and mitotic index (MI). Lipid peroxidation analysis was also performed in A. sativum root tip cells for determination of membrane damage. MN exhibited a dose-dependent increase in Cd treatments in A. sativum. GA(3) significantly reduced the effect of Cd on the MN frequency. MN was observed in GA(3) and GA(3) + 50 mum Cd treatments at very low frequency. MI slightly decreased in GA(3) and GA(3) + Cd treatments. MI decreased more in high concentrations of Cd than combined GA(3) + Cd treatments. The high concentrations of cadmium induce MN, lipid peroxidation and lead to genotoxicity in A. sativum. Current work reveals that the effect of Cd on genotoxicity can be partially restored with GA(3) application. PMID:17668283

  7. 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

  8. Comet and micronucleus assays in zebra mussel cells for genotoxicity assessment of surface drinking water treated with three different disinfectants.

    PubMed

    Bolognesi, Claudia; Buschini, Annamaria; Branchi, Elisa; Carboni, Pamela; Furlini, Mariangela; Martino, Anna; Monteverde, Martino; Poli, Paola; Rossi, Carlo

    2004-10-15

    The aim of this research was to study the influence of classic (sodium hypochlorite and chlorine dioxide) and alternative (peracetic acid [PAA]) disinfectants on the formation of mutagens in surface waters used for human consumption. For this proposal, in vivo genotoxicity tests (Comet and micronucleus assay) were performed in an experimental pilot plant set up near Lake Trasimeno (Central Italy). The effects were detected in different tissues (haemocytes for the Comet assay and gills for the micronucleus test [MN]) of Dreissena polymorpha exposed in experimental basins supplied with lake water with/without the different disinfectants. Specimen collection was performed before disinfectant input for both tests and after the start of disinfection (3 h and 20 days for the Comet assay and 10 and 20 days for micronucleus test, respectively) to assess short- and long- term exposure effects during three sampling campaigns (October 2000, February 2001, and June 2001). Seasonal differences in baseline levels of DNA migration and micronucleus frequency were observed. Raw water quality modulation on disinfection by-product formation was shown. The results of the micronucleus and Comet assays on zebra mussel cells after in situ exposure to water disinfected with the two chlorinated compounds clearly indicate DNA/by-product interaction. PAA did not induce either clastogenic/aneugenic effects or DNA damage on this bioindicator. PMID:15364524

  9. 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. PMID:25953396

  10. Antigenotoxicity of Roupala montana extract in the mouse micronucleus and comet assays.

    PubMed

    Francielli de Oliveira, Pollyanna; Acésio, Nathália Oliveira; Leandro, Luís Fernando; Cunha, Nayanne Larissa; Uchôa, Camila Jacintho de Mendonça; Januário, Ana Helena; Tavares, Denise Crispim

    2014-01-01

    Roupala montana Aubl. (Proteaceae) is a typical savannah species and native to tropical South America that has a moderate mortality for adult forms of Schistossoma mansoni. Because this species has been little studied, the aim of this investigation was to evaluate the influence of R. montana extract on DNA damage induced by methyl methanesulfonate (MMS) in peripheral blood cells and liver of Swiss mice using the micronucleus and comet assay, respectively. R. montana dichloromethane extract was prepared from a stock solution (0.5 mg/mL) in 5% dimethyl sulfoxide in water. Animals received a single dose of different concentrations of R. montana (5, 10 and 20 mg/kg body weight) by gavage (0.5 mL/animal). For antigenotoxicity assessment, different concentrations of R. montana were administered simultaneously with MMS diluted in water (40 mg/kg, intraperitoneally; 0.3 mL/animal). Peripheral blood and hepatocyte samples were obtained 48 and 24 h after treatment, respectively. Results showed that R. montana administered alone indicated the absence of genotoxicity in the mouse micronucleus or comet assay. On the other hand, administration of different doses of R. montana concomitantly with MMS led to a significant reduction in frequency of micronucleated polychromatic erythrocytes and DNA damage, when compared to the group treated only with MMS. Further, for the micronucleus assay, the gradual increase of R. montana concentration led to a proportional increase in the reduction of genotoxicity induced by MMS, indicating a dose-response relationship. PMID:24099505

  11. The assessment of genotoxicity of carbamazepine using cytokinesis-block (CB) micronucleus assay in cultured human blood lymphocytes.

    PubMed

    Celik, Ayla

    2006-01-01

    The genotoxic effect of CBZ has been investigated in few studies. There is little evidence linking carbamazepine (CBZ) with any genotoxic effects, particularly in vitro micronucleus test using cytogenesis-block technique. In this study, the genotoxicity of the antiepileptic drug, carbamazepine, was tested using cytokinesis-block (CB) micronucleus assay. In vitro analysis was performed in human blood lymphocytes from four healthy persons at five different concentrations of carbamazepine (6, 8, 10, 12, 14 microg/mL). Genotoxic potential and cytotoxic effects of carbamazepine were evaluated by using micronucleus assay and cytokinesis-block proliferation index (CBPI), called the parameter of cytotoxicity in human peripheral blood lymphocyte cultures, respectively. The results of this study indicate that CBZ caused the genotoxic effect under in vitro conditions, except at the dose of 6 microg/mL, and cytotoxic effects of carbamazepine were revealed by a decrease in the cytokinesis-block proliferation index at all the concentrations. PMID:16707330

  12. Coking wastewater increases micronucleus frequency in mouse in vivo via oxidative stress.

    PubMed

    Zhu, Na; Li, Hongyan; Li, Guangke; Sang, Nan

    2013-10-01

    Coking wastewater has caused serious health risk in coal-producing areas of China, however its toxic effects have not been well understood. The genotoxicity induced by coking wastewater on mice in vivo and its possible oxidative mechanisms were investigated via observing the induction of micronuclei in polychromatic erythrocytes of mouse bone marrow, and subsequently determining the antioxidative enzyme activities (superoxide dismutase Cu, Zn-SOD, Se-dependent glutathione peroxidase, and catalase), thiobarbituric acid reactive substance contents and protein carbonyl levels in brains and livers of mice. Results showed that the tested coking wastewater caused a significant increase of micronucleus frequencies in a concentration-dependent manner. Also, the sample increased lipid peroxidation and protein oxidation levels, which was accompanied by changes in antioxidative status. Interestingly, pre-treatment with an antioxidant (vitamin C) led to a statistical reduction in the micronucleus frequency caused by coking wastewater. This implies that coking wastewater induces evident genetic damage in mammalian cells, and exposure to polluted areas might pose a potential genotoxic risk to human beings; in the process, oxidative stress played a crucial role. PMID:24494500

  13. 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.

  14. 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. PMID:26333298

  15. Best practices for application of attachment cells to in vitro micronucleus assessment by flow cytometry.

    PubMed

    Bemis, Jeffrey C; Bryce, Steven M; Nern, Marlies; Raschke, Marian; Sutter, Andreas

    2016-01-01

    This work seeks to provide users with guidance on cell culture, treatment, processing and analytical conditions for achieving optimal performance of the in vitro micronucleus assay using the In Vitro MicroFlow(®) method. Experimental data are provided to support the advice described. The information provided covers specific topics or issues that are identified as critical to the methodology and thus is meant to work with instruction manuals, published papers and other references, and not as a replacement for these documents. The content is divided into several sections. Cell culture and treatment describes conditions for routine maintenance of cells as well as treatment with test articles. Preparation and processing of samples details steps found to be critical in execution of the procedure. Instrument parameters and analysis covers set-up of the flow cytometer and evaluation of the samples. General assay considerations and interpretation of results describes examination of data in terms of assay validity, viability and genotoxicity assessment. The goal is to educate users and enable them to design, conduct and interpret flow cytometric in vitro micronucleus (MN) studies. Readers should obtain an understanding of specific cell culture practices, options for assay formatting and execution and the information required to successfully integrate and validate the in vitro MN assay into their existing safety program. PMID:26774667

  16. Evaluation of genotoxicity of clofazimine, an antileprosy drug, in mice in vivo. II. Micronucleus test in bone marrow and hepatocytes.

    PubMed

    Roy, B; Das, R K

    1990-06-01

    The antileprosy drug, clofazimine, was tested for its possible genotoxicity using micronucleus (MN) tests in mice. A significantly higher incidence of MN in bone marrow erythrocytes, particularly in polychromatic erythrocytes, as well as in regenerated hepatocytes revealed a positive clastogenic effect of the drug. The drug also had a marked antimitotic effect as indicated by a negative correlation with the dose. PMID:2345555

  17. 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...

  18. 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. PMID:26242975

  19. 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. PMID:25167825

  20. Studies on three structurally related phenylenediamines with the mouse micronucleus assay system.

    PubMed

    Soler-Niedziela, L; Shi, X; Nath, J; Ong, T

    1991-01-01

    Three structurally related compounds, 4-chloro-o-phenylenediamine (COP), 4-nitro-o-phenylenediamine (NOP) and p-phenylenediamine dihydrochloride (PPD), are used in fur dyes, inks and hair coloring formulations. COP has been reported to be carcinogenic in both rats and mice. NOP and PPD are non-carcinogens, but have consistently tested positive in short-term in vitro genotoxicity assays. Studies were undertaken to evaluate their genotoxicity with the in vivo mouse bone-marrow micronucleus assay. Five CD-1 male mice per dose were injected i.p. with the compounds and sacrificed at intervals of 24, 48 and 72 h. 2000 cells were scored per animal to determine the frequency of micronucleated-polychromatic erythrocytes (MPCE). COP induced significant dose-related increases in MPCE over the 3 doses tested at each of the sampling intervals. The peak response occurred at 24 h. No response was observed in animals treated with PPD or NOP. PMID:1703280

  1. Monitoring genotoxicity in freshwater microcrustaceans: A new application of the micronucleus assay.

    PubMed

    Barka, S; Ouanes, Z; Gharbi, A; Gdara, I; Mouelhi, S; Hamza-Chaffai, A

    2016-06-01

    We have applied the micronucleus (MN) assay to the measurement of genotoxicity in microcrustaceans. Daphnids (Daphnia magna) and Copepods (Acanthocyclops robustus) were collected in situ and acclimated in the lab for 24h. The MN assay was successful with the Daphnids but not with the Copepods. Adult Daphnids were exposed to sublethal concentrations of metals (Cu, Zn, Cd) or insecticide (deltamethrin) for 2 and 7d. Dose-dependent induction of MN was observed after 2 d exposure, with 2-fold induction at the highest doses for each chemical tested. The advantages and ecological relevance of using Daphnids in genotoxicity assessment are highlighted. The Daphnid assay may be a reliable test for aquatic genotoxicity hazard/risk assessment and a useful alternative to studies of amphibians. PMID:27265377

  2. The reconstructed skin micronucleus assay (RSMN) in EpiDerm™: detailed protocol and harmonized scoring atlas.

    PubMed

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

    2011-02-28

    The European Cosmetic Toiletry and Perfumery Association (COLIPA), along with contributions from the European Centre for the Validation of Alternative Methods (ECVAM), initiated a multi-lab international prevalidation project on the reconstructed skin micronucleus (RSMN) assay in EpiDerm™ for the assessment of the genotoxicity of dermally applied chemicals. The first step of this project was to standardize the protocol and transfer it to laboratories that had not performed the assay before. Here we describe in detail the protocol for the RSMN assay in EpiDerm™ and the harmonized guidelines for scoring, with an atlas of cell images. We also describe factors that can influence the performance of the assay. Use of these methods will help new laboratories to conduct the assay, thereby further increasing the database for this promising new in vitro genotoxicity test. PMID:21147256

  3. 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. PMID:24768639

  4. Micronucleus test and metaphase analyses in mice exposed to known and suspected spindle poisons.

    PubMed

    Marrazzini, A; Betti, C; Bernacchi, F; Barrai, I; Barale, R

    1994-11-01

    Micronucleus (Mn) and metaphase chromosome analyses were performed in mouse bone marrow cells with two known and eight suspected mitotic spindle poisons. Polychromatic (PCEs) and normochromatic (NCEs) erythrocytes were scored for presence of Mn, while structural (CAs) and numerical chromosome aberrations (NCAs), i.e. hyperploid cells, were evaluated by metaphase analysis. CAs were scored in first, and NCAs in the second metaphases, identified by BrdUrd differential staining. Hydroquinone induced Mn, NCAs and CAs; colchicine, vinblastine and, to a lesser extent, chloral hydrate, diazepam and econazole induced both Mn and NCAs; cadmium chloride and thimerosal induced Mn and CAs, while pyrimethamine and thiabendazole induced Mn only. The proposed stepwise protocol allowed satisfactory statistical evaluation of the effects induced with a reduction in the number of animals killed. An acceptable agreement was found between induction of Mn and NCAs, suggesting a possible use of the Mn test for revealing compounds with aneugenic properties. PMID:7854141

  5. 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. PMID:26616377

  6. 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. PMID:27352027

  7. 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

  8. 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

  9. Investigating micronucleus assay applicability for prediction of normal tissue intrinsic radiosensitivity in gynecological cancer patients

    PubMed Central

    Encheva, Elitsa; Deleva, Sofia; Hristova, Rositsa; Hadjidekova, Valeria; Hadjieva, Tatiana

    2011-01-01

    Background Pelvic organs morbidity after irradiation of cancer patients remains a major problem although new technologies have been developed and implemented. A relatively simple and suitable method for routine clinical practice is needed for preliminary assessment of normal tissue intrinsic radiosensitivity. The micronucleus test (MNT) determines the frequency of the radiation induced micronuclei (MN) in peripheral blood lymphocytes, which could serve as an indicator of intrinsic cell radiosensitivity. Aim To investigate a possible use of the micronucleus test (MNT) for acute radiation morbidity prediction in gynecological cancer patients. Materials and methods Forty gynecological cancer patients received 50 Gy conventional external pelvic irradiation after radical surgery. A four-field “box” technique was applied with 2D planning. The control group included 10 healthy females. Acute normal tissue reactions were graded according to NCI CTCAE v.3.0. From all reaction scores, the highest score named “summarized clinical radiosensitivity” was selected for a statistical analysis. MNT was performed before and after in vitro irradiation with 1.5 Gy. The mean radiation induced frequency of micronuclei per 1000 binucleated cells (MN/1000) and lymphocytes containing micronuclei per 1000 binucleated cells (cells with MN/1000) were evaluated for both patients and controls. An arbitrary cut off value was created to pick up a radiosensitive individual: the mean value of spontaneous frequency of cells with MN/1000 ± 2SD, found in the control group. Results Both mean spontaneous frequency of cells with MN/1000 and MN/1000 were registered to be significantly higher in cancer patients compared to the control group (t = 2.46, p = 0.02 and t = 2.51, p = 0.02). No statistical difference was registered when comparing radiation induced MN frequencies between those groups. Eighty percent (32) of patients developed grade 2 summarized clinical radiosensitivity, with

  10. Pre-bled-young-rats in genotoxicity testing: a model for peripheral blood micronucleus assay.

    PubMed

    Vikram, A; Tripathi, D N; Pawar, A A; Ramarao, P; Jena, G B

    2008-11-01

    Previously we have reported that prior bleeding increases the sensitivity of micronucleus (MN) assay in rats (Vikram et al., 2007 a). Rat peripheral blood micronucleus (PBMN) assay is generally not considered as reliable method for the assessment of clastogenic potential of test chemicals due to selective elimination of micronucleated cells from the circulation. The present study is aimed to evaluate the sensitivity of pre-bled-young-rat model in detecting genotoxins having different mechanism of action. In the present study, young male Sprague-Dawley (SD) rats (21-24 days old, weighing 60+/-5 g) and swiss mice (24-28 days old, weighing 15+/-2g) were used. Streptozotocin (STZ, 50mg/kg), Methotrexate (MTX, 10mg/kg), N-nitrosodiethylamine (DEN, 200mg/kg), Quercetin (QC, 50mg/kg) and Zidovudine (AZT, 400mg/kg) were used in the present experiment. Effect of prior bleeding time (0, 2, 6, 12 and 24h) on the kinetics of MN formation with STZ and AZT was studied and 36 h post chemical exposure was found to be the most suitable time point for sample collection if prior bleeding time was 0, 2 and 6h. Further, the impact of prior bleeding (2h) on the kinetics of MN formation in the bone marrow was evaluated with STZ and maximum MN frequency was observed after 24h. The area under curve (AUC) analysis proves that prior bleeding leads to significant increase in the incidence of micronucleated reticulocytes (RETs) in the peripheral blood as compared to respective non-bled controls. Out of five tested chemicals AZT and STZ induced significant increase in the MN frequency in non-bled animals while at the same dose MTX, AZT, QC and STZ induced significant increase in MN frequency in the pre-bled-young-rats employing PBMN assay as the end point. Positive results with MTX, AZT, QC, STZ and negative results with DEN demonstrate both the sensitivity and specificity of pre-bled-young-rat model in the screening of chemicals for genotoxicity using PBMN assay as the end point. PMID:18721840

  11. 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

  12. [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. PMID:27548984

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

    PubMed

    Chapman, K E; Thomas, A D; Wills, J W; Pfuhler, S; Doak, S H; Jenkins, G J S

    2014-05-01

    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 vivo

  14. 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

  15. In vitro testing for genotoxicity of indigo naturalis assessed by micronucleus test.

    PubMed

    Dominici, Luca; Cerbone, Barbara; Villarini, Milena; Fatigoni, Cristina; Moretti, Massimo

    2010-07-01

    In the field of cosmetic dyes, used for coloring the hair and skin, there is a clear tendency to replace the widely used synthetic dyes by natural colorants, such as henna and mixtures of henna with indigo. The aim of this study was to estimate the genotoxicity of water and DMSO solutions of indigo naturalis (prepared from Indigofera tinctoria leaves) using the cytokinesis-blocked micronucleus (CBMN) assay in the human metabolically active HepG2 cell line. The cytotoxic effects of indigo solutions were first assessed by propidium iodide and fluorescein-diacetate simultaneous staining. For both solutions, cytotoxicity was always under 10%. Data obtained in the CBMN assay (for all concentrations tested) indicated that the frequency of MN (micronuclei) in exposed cells was no higher than the control. Both the water and DMSO solutions showed the same behavior. These results indicate that indigo naturalis exhibits neither cytotoxicity, nor genotoxicity for all concentrations tested, which may justify excluding indigofera and its components from the list of carcinogenic agents. PMID:20734936

  16. Kinetics of micronucleus induction and cytotoxicity caused by distinct antineoplastics and alkylating agents in vivo.

    PubMed

    Morales-Ramírez, Pedro; Vallarino-Kelly, Teresita; Cruz-Vallejo, Virginia

    2014-01-30

    This mini-review aims to compare the differences in the kinetics of the induction of micronucleated polychromatic erythrocytes (MN-PCE) and cytotoxicity by distinct antineoplastic and genotoxic agents in murine peripheral blood in vivo and to correlate these kinetics with the underlying processes. Comparisons were carried out using our previously obtained data with nominal doses causing similar levels of cytotoxicity, as measured in terms reduction of PCE. The aneuploidogens caused the most rapid induction of MN-PCEs and had the highest rates of cytotoxicity and genotoxicity. The promutagens cyclophosphamide and dimethylnitrosamine showed the most delayed responses and had the lowest genotoxic and cytotoxic efficiencies. DNA crosslinking agents had a similar delay of 4-5 h, greater than those of aneuploidogens, but differed in their cytotoxic and genotoxic efficiencies. Methylnitrosourea and 5-aza-cytidine caused greater delays than crosslinking agents. These delays can be due to the methylnitrosourea-mediated induction of formation of mono alkyl adducts which are interpreted as mismatches during DNA duplication, whereas 5-aza-cytidine requires incorporation into the DNA to induce breakage. This review allows us to conclude that the requirement for metabolic activation and the mechanisms of DNA breakage and of micronucleus induction are the main factors that affect the time of maximal MN-PCE induction. PMID:24269717

  17. In vivo rodent micronucleus assay of gmelina arborea roxb (gambhari) extract.

    PubMed

    Sahu, Rohit; Divakar, Goli; Divakar, Kalyani

    2010-01-01

    Gmelina arborea Roxb (family Verbenaceae) commonly known as 'Gambhari' tree, the various parts of the plants are widely used in diarrhoea, anti-pyretic, thirst, anemia, leprosy, ulcers, consumption, strangury, vaginal discharges. We tested the genotoxic potential of G. arborea in bone marrow cells obtained from Swiss albino mice using micronuclei formation as the toxicological endpoints. Aqueous extract of G. arborea (AEGA) was tested at the dose of 286 & 667 mg/kg body weight (b. w.). Cyclophosphamide (CPZ) 25 mg/kg b. w. was used as positive control in micronucleus test. The AEGA significantly increased the % micronucleated polychrometics at doses of 286mg/kg and 667mg/kg, after 24, 48 72h time interval. And also decreased the PCE/NCE ratio after 24, 48 and 72 h as compared to solvent control group. In this study, we investigated the effect of G. arborea on mammalian bone marrow cells using micronuclei formation to assess the genotoxicity of the herb. PMID:22247828

  18. 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. PMID:26046975

  19. Artichoke induces genetic toxicity in the cytokinesis-block micronucleus (CBMN) cytome assay.

    PubMed

    Jacociunas, Laura Vicedo; de Andrade, Heloisa Helena Rodrigues; Lehmann, Mauricio; de Abreu, Bianca Regina Ribas; Ferraz, Alexandre de Barros Falcão; da Silva, Juliana; Grivicich, Ivana; Dihl, Rafael Rodrigues

    2013-05-01

    Artichoke leaves are used in traditional medicine as an herbal medicament for the treatment of hepatic related diseases, as well as choleretic and diuretic. The aim of the present study was to evaluate the capacity of Cynara scolymus L. leaves extract (LE) to cause chromosomal instability and cytotoxicity in Chinese hamster ovary cells (CHO) employing the cytokinesis-block micronucleus (CBMN) cytome assay. Cells were treated with four concentrations of C. scolymus for two exposure times: 1h and 24h. Our findings showed that LE did not increase the frequencies of nucleoplasmic bridges (NPBs) and nuclear bud (NBUD). However, all concentrations of the extract produced increments in micronuclei frequencies (MNi) in both exposure times, when compared to the negative control. No significant differences were observed in the nuclear division cytotoxicity index (NDCI), reflecting the absence of cytotoxic effects associated to LE. The results demonstrated the ability of C. scolymus LE to promote chromosomal mutations which are, probably, a result of the pro-oxidant activity of LE constituents such as flavonoids and chlorogenic acids. The data obtained in this study suggests that high concentrations of artichoke can pose a risk associated to its consumption. PMID:23274746

  20. Effects of dental adhesives on micronucleus frequency in peripheral blood lymphocytes in vitro.

    PubMed

    Prica, Dunja; Tadin, Antonija; Marović, Danijela; Katunarić, Marina; Prica, Adriana; Galić, Nada

    2013-09-01

    Dental adhesives come into direct contact with oral tissues. Due to this close and long-term contact, the materials should exhibit a high degree of biocompatibility. The aim of this study was to evaluate the genotoxic effect of dental adhesives on human lymphocytes in vitro. Polymerized dental adhesives (Excite, Adper Single Bond 2, Prompt L-pop and OptiBond Solo Plus) were eluted in dimethyl sulfoxide for 1 hour, 24 h and 120 h (5 days). Thereafter, lymphocyte cultures were treated with different concentrations of eluates (0.2 microg/mL, 0.5 microg/mL and 5 microg/mL) obtained from each of the tested materials. Genotoxicity was evaluated by micronucleus test. The chi2-test was used on statistical analysis (p < 0.05). After elution period of 1 h, only the highest dose of all tested materials affected the measured cytogenetic parameters. After 24 h, genotoxicity was demonstrated only in cultures treated with eluates in concentrations of 0.5 microg/mL and 5 microg/mL. Based on the results, it is concluded that the use of dental adhesives causes genotoxic effects in human lymphocytes. Toxic effect of these dental adhesives increases with the tested material concentration and decreases with the length of elution period. PMID:24558762

  1. 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

  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. A lifetime passion for micronucleus cytome assays--reflections from Down Under.

    PubMed

    Fenech, Michael

    2009-01-01

    A brief account of an improbable career in the field of genetic toxicology is given, extending from my early years in Malta through a life-changing decision to study in Australia (Down Under). I describe the circumstances that led to the discovery of the cytokinesis-block micronucleus (CBMN) assay and its evolution into a cytome assay of chromosome breakage and loss (micronuclei), asymmetrical chromosome rearrangements or telomere end fusions (nucleoplasmic bridges), gene amplification (nuclear buds), cell death (necrosis, apoptosis) and cytostasis (nuclear division index). This paper also describes the role of my laboratory in the beginning of the HUMN project, its achievements, and the applications of CBMN cytome assays in the fields of radiation biology, genetic toxicology, epidemiology, biodosimetry and genome health nutrigenomics, leading to the Genome Health Clinic concept. Along the way I mention my encounters with some of the influential people in the field of mutagenesis who provided me with the motivation and guidance needed to realise these achievements. I hope this account provides some inspiration to the next generation of scientists who may be fortunate to see the realisation of the application of the principles of mutagenesis in health optimisation or disease prevention and eventually in mainstream medicine. PMID:19100861

  4. 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. PMID:24927390

  5. Application of cell sorting for enhancing the performance of the cytokinesis-block micronucleus assay

    PubMed Central

    Nakamura, Ayumi; Monzen, Satoru; Takasugi, Yuki; Wojcik, Andrzej; Mariya, Yasushi

    2016-01-01

    Among the numerous methods available to assess genotoxicity, the cytokinesis-block micronucleus (CBMN) assay is very popular due its relative simplicity and power to detect both clastogenic and aneugenic compounds. A problem with the CBMN assay is that all DNA damaging agents also inhibit the ability of cells to progress through mitosis, leading to a low number of binucleated cells (BNCs). One method to resolve this issue is to ensure a sufficient proportion of BNCs in the samples. In the current study, the applicability of a cell sorting system capable of isolating cell fractions containing abundant BNCs was investigated. Furthermore, to investigate the relationship between the cell division delay due to radiation exposure and the generation of BNCs and micronuclei (MN), we assessed a series of lag times between radiation exposure and addition of cytochalasin-B (Cyt-B). Cells from the human chronic myelogenous leukemia cell line K562 were exposed to X-rays (2 Gy and 4 Gy), and Cyt-B was subsequently added at 0, 6 and 12 h following irradiation. After treatment with Cyt-B for 24 h, the percentage of BNCs, the MN frequency and the cell cycle distribution were analyzed. In addition, cells displaying the DNA contents corresponding to BNCs were isolated and analyzed. The results indicate that applying the cell sorter to the CBMN assay increased the percentage of BNCs compared with the standard method. Thus, this technique is a promising way of enhancing the capacity of the CBMN assay. PMID:26826197

  6. 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. PMID:25953397

  7. 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

  8. [Values of the micronucleus test on animal epithelial cells exposed to titanium dioxide].

    PubMed

    Iurchenko, V V; Krivtsova, E K; Iuretseva, N A; Tul'skaia, E A; Mamonov, R A; Zholdakova, Z I; Sinitsyna, O O; Mal'tseva, M M; Pankratova, G P; Sycheva, L P

    2011-01-01

    The genetic safety of titanium dioxide (TD)-containing foods and cosmetic products has been little investigated. The study evaluated the mutagenic activity of TD in the micronucleus test with animal visceral mucosal epithelial cells. Two simethicone-coated anatase samples (mean size 160 and 33.2 nm) were inserted into the mouse stomach in doses of 40-200-1000 mg/kg seven times and applied as an ingredient of 10 and 25% cream (doses 250 and 625 mg/kg, respectively) to the hair-sheared rat skin once for 4 hours. Analysis of cytogenetic disorders (micronuclei, protrusions, and the atypical form of the nucleus) revealed no mutagenic properties of TD on the mucosal epithelium of the mouse and rat intestine, mouse prostomach, and rat uterine bladder. Enhanced mitotic activity was observed in all the study tissues after exposure of both samples to TD given in some or in all (in the rat urinary bladder mucosal epithelium) doses. PMID:22185006

  9. Application of micronucleus test and comet assay to evaluate BTEX biodegradation.

    PubMed

    Mazzeo, Dânia Elisa Christofoletti; Matsumoto, Silvia Tamie; Levy, Carlos Emílio; de Angelis, Dejanira de Franceschi; Marin-Morales, Maria Aparecida

    2013-01-01

    The BTEX (benzene, toluene, ethylbenzene and xylene) mixture is an environmental pollutant that has a high potential to contaminate water resources, especially groundwater. The bioremediation process by microorganisms has often been used as a tool for removing BTEX from contaminated sites. The application of biological assays is useful in evaluating the efficiency of bioremediation processes, besides identifying the toxicity of the original contaminants. It also allows identifying the effects of possible metabolites formed during the biodegradation process on test organisms. In this study, we evaluated the genotoxic and mutagenic potential of five different BTEX concentrations in rat hepatoma tissue culture (HTC) cells, using comet and micronucleus assays, before and after biodegradation. A mutagenic effect was observed for the highest concentration tested and for its respective non-biodegraded concentration. Genotoxicity was significant for all non-biodegraded concentrations and not significant for the biodegraded ones. According to our results, we can state that BTEX is mutagenic at concentrations close to its water solubility, and genotoxic even at lower concentrations, differing from some described results reported for the mixture components, when tested individually. Our results suggest a synergistic effect for the mixture and that the biodegradation process is a safe and efficient methodology to be applied at BTEX-contaminated sites. PMID:22980962

  10. Fluorescence in situ hybridization in combination with the comet assay and micronucleus test in genetic toxicology

    PubMed Central

    2010-01-01

    Comet assay and micronucleus (MN) test are widely applied in genotoxicity testing and biomonitoring. While comet assay permits to measure direct DNA-strand breaking capacity of a tested agent MN test allows estimating the induced amount of chromosome and/or genome mutations. The potential of these two methods can be enhanced by the combination with fluorescence in situ hybridization (FISH) techniques. FISH plus comet assay allows the recognition of targets of DNA damage and repairing directly. FISH combined with MN test is able to characterize the occurrence of different chromosomes in MN and to identify potential chromosomal targets of mutagenic substances. Thus, combination of FISH with the comet assay or MN test proved to be promising techniques for evaluation of the distribution of DNA and chromosome damage in the entire genome of individual cells. FISH technique also permits to study comet and MN formation, necessary for correct application of these methods. This paper reviews the relevant literature on advantages and limitations of Comet-FISH and MN-FISH assays application in genetic toxicology. PMID:20840797

  11. Biomonitoring of low levels of mercurial derivatives in water and soil by Allium micronucleus assay.

    PubMed

    Dash, S; Panda, K K; Panda, B B

    1988-02-01

    The Allium micronucleus (MNC) assay was developed to monitor low levels of mercury in aquatic and terrestrial environments. Four mercurial derivatives namely mercuric chloride (MC), methyl mercuric chloride (MMC), phenyl mercuric acetate (PMA) and a methoxy ethyl mercuric chloride based fungicide, Emisan-6, were tested to assess the sensitivity and versatility of the Allium MNC assay. Allium bulbs were set directly on water and soil contaminated with known levels of mercurial derivatives (0.0001-10.00 ppm). On the 5th day the endpoints measured were root length, mitoses with spindle abnormality and cells with MNC in root meristems. The effective concentrations of the test chemicals that cause 50% of root length as compared to control (EC50) were determined from dose-response curves so obtained. The lowest effective concentration tested (LECT) and highest ineffective concentration tested (HICT) for each of the mercurial derivatives for the induction of spindle malfunction and MNC were determined. It was found that EC50, LECT and HICT values for mercurial derivatives in soil were higher than those in water. The frequencies of cells with MNC and mitoses with spindle abnormality were highly correlated indicating that MNC is a good parameter of spindle malfunction. The present approach increased the sensitivity of the Allium assay by 10-fold, the detection limit being 0.001-0.1 ppm and 0.1-1.0 ppm in aquatic and terrestrial environments respectively, depending on the species of mercury. PMID:3340089

  12. The in vivo rodent micronucleus assay of Kacip Fatimah (Labisia pumila) extract.

    PubMed

    Zaizuhana, Shahrim; Puteri J Noor, M B; Noral'ashikin, Yahya; Muhammad, Hussin; Rohana, A B; Zakiah, I

    2006-12-01

    Kacip Fatimah also known as Labisia pumila (Myrsinaceae), is a traditional herbal medicine with a long history in the Malay community. It has been used by many generations of Malay women to induce and facilitate childbirth as well as a post-partum medicine. We tested the genotoxic potential of Kacip Fatimah in bone marrow cells obtained from Sprague-Dawley rats using micronuclei formation as the toxicological endpoints. Five groups of five male rats each were administered orally for two consecutive days with doses of 100, 700 and 2000 mg/kg body weight of Kacip Fatimah extract dissolved in distilled water. Micronucleus preparation was obtained from bone marrow cells of the animals following standard protocols. No statistically significant increase in micronucleated polychromatic erythrocytes (MNPCEs) was observed at any dose level and sacrifice/harvest time point (24, 48 and 72h). However, a significant decrease in polychromatic erythrocytes/normochromatic erythrocytes (PCE:NCE) ratio was observed from the highest dose level (2000 mg/kg of body weight) at 48h harvest time point. In this study, we investigated the effect of Kacip Fatimah on mammalian bone marrow cells using micronuclei formation to assess the genotoxicity of the herb. PMID:17322824

  13. IN VIVO RODENT MICRONUCLEUS ASSAY OF GMELINA ARBOREA ROXB (GAMBHARI) EXTRACT

    PubMed Central

    Sahu, Rohit; Divakar, Goli; Divakar, Kalyani

    2010-01-01

    Gmelina arborea Roxb (family Verbenaceae) commonly known as ‘Gambhari’ tree, the various parts of the plants are widely used in diarrhoea, anti-pyretic, thirst, anemia, leprosy, ulcers, consumption, strangury, vaginal discharges. We tested the genotoxic potential of G. arborea in bone marrow cells obtained from Swiss albino mice using micronuclei formation as the toxicological endpoints. Aqueous extract of G. arborea (AEGA) was tested at the dose of 286 & 667 mg/kg body weight (b. w.). Cyclophosphamide (CPZ) 25 mg/kg b. w. was used as positive control in micronucleus test. The AEGA significantly increased the % micronucleated polychrometics at doses of 286mg/kg and 667mg/kg, after 24, 48 72h time interval. And also decreased the PCE/NCE ratio after 24, 48 and 72 h as compared to solvent control group. In this study, we investigated the effect of G. arborea on mammalian bone marrow cells using micronuclei formation to assess the genotoxicity of the herb. PMID:22247828

  14. Micronucleus assay in human lymphocytes after exposure to alloxydim sodium herbicide in vitro.

    PubMed

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

    2015-12-01

    This study evaluates the cytotoxic and genotoxic potential of alloxydim sodium using micronucleus (MN) assay, in human peripheral lymphocytes. MN assay was used to investigate the genotoxic effects of alloxydim sodium in human peripheral lymphocytes treated with 250, 500, 750, 1,000 µg/ml concentrations of alloxydim sodium for 24 and 48 h. Solvent, negative and positive controls were also used in the experiments in parallel. The obtained results were evaluated in statistical analyses by using Dunnett-t test (two sided) and p < 0.05 was accepted as significant. Alloxydim sodium significantly increased the MN formation compared with the negative control, at both 750 and 1,000 µg/ml concentrations and treatment periods. We also evaluated the nuclear division index (NDI) for cytotoxicity of this pesticide in the experiment, and finally observed a significant decrease of the NDI values at all concentrations of alloxydim sodium and at both treatment periods. PMID:25017922

  15. 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. PMID:26927934

  16. Vitamin B12 and methionine deficiencies induce genome damage measured using the cytokinesis-block micronucleus cytome assay in human B lymphoblastoid cell lines.

    PubMed

    Wu, Xiayu; Cheng, Jiaoni; Lu, Lin

    2013-01-01

    One-carbon metabolism is a network of interrelated biochemical reactions that has 2 major functions: DNA methylation and DNA synthesis. Methionine (Met), an essential amino acid, is converted to S-adenosyl-methionine (SAM), the body's main methyl group donor, which is converted to S-adenosylhomocysteine during methylation reactions. Vitamin B12 (B12) acts as a coenzyme of methionine synthase, which is required for the synthesis of Met and SAM. To determine the effects of Met and B12, we used the cytokinesis-block micronucleus assay in GM13705 and GM12593 cell line cultures exposed to 13 unique combinations of B12 and Met concentrations over 9 days. The nutrient levels chosen span the normal physiological ranges in humans. The Met-B12 concentration significantly and negatively correlated with all markers of genotoxicity in the 2 cell lines tested. In both cell lines, all markers of genotoxicity were significantly higher when treated with 15 μM Met than when treated with 50 μM Met, regardless of the B12 treatment level. Genotoxicity was significantly reduced in the group treated with 50 μM Met and 600 pM B12. Concentrations of 50 μM Met and 600 pM B12 are an optimal combination for stabilizing the genome. It is advisable to acquire adequate amounts of Met and B12 for maintaining genome stability. PMID:23909731

  17. 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.

  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. PMID:25892620

  19. Adaption of the Cytokinesis-Block Micronucleus Cytome Assay for Improved Triage Biodosimetry.

    PubMed

    Beinke, C; Port, M; Riecke, A; Ruf, C G; Abend, M

    2016-05-01

    The purpose of this work was to adapt a more advanced form of the cytokinesis-block micronucleus (CBMN) cytome assay for triage biodosimetry in the event of a mass casualty radiation incident. We modified scoring procedures for the CBMN cytome assay to optimize field deployability, dose range, accuracy, speed, economy, simplicity and stability. Peripheral blood of 20 donors was irradiated in vitro (0-6 Gy X ray, maximum photon energy 240 keV) and processed for CBMN. Initially, we assessed two manual scoring strategies for accuracy: 1. Conventional scoring, comprised of micronucleus (MN) frequency per 1,000 binucleated (BN) cells (MN/1,000 BN cells); and 2. Evaluation of 1,000, 2,000 and 3,000 cells in total and different cellular subsets based on MN formation and proliferation (e.g., BN cells with and without MN, mononucleated cells). We used linear and logistic regression models to identify the cellular subsets related closest to dose with the best discrimination ability among different doses/dose categories. We validated the most promising subsets and their combinations with 16 blind samples covering a dose range of 0-8.3 Gy. Linear dose-response relationships comparable to the conventional CBMN assay (r(2) = 0.86) were found for BN cells with MN (r(2) = 0.84) and BN cells without MN (r(2) = 0.84). Models of combined cell counts (CCC) of BN cells with and without MN (BN(+MN) and BN(-MN)) with mononucleated cells (Mono) improved this relationship (r(2) = 0.92). Conventional CBMN discriminated dose categories up to 3 Gy with a concordance between 0.96-1.0 upon scoring 1,000 total cells. In 1,000 BN cells, concordances were observed for conventional CBMN up to 4 Gy as well as BN(+MN) or BN(-MN) (about 0.85). At doses of 4-6 Gy, the concordance of conventional CBMN, BN(+MN) and BN(-MN) declined (about 0.55). We found about 20% higher concordance and more precise dose estimates of irradiated and blinded samples for CCC (Mono + BN(+MN)) after scoring 1,000 total cells

  20. 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. PMID:24618993

  1. Estimating the carcinogenic potency of chemicals from the in vivo micronucleus test.

    PubMed

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

    2016-05-01

    In this study, we investigated the applicability of using in vivo mouse micronucleus (MN) data to derive cancer potency information. We also present a new statistical methodology for correlating estimated potencies between in vivo MN tests and cancer studies, which could similarly be used for other systems (e.g. in vitro vs. in vivo genotoxicity tests). The dose-response modelling program PROAST was used to calculate benchmark doses (BMDs) for estimating the genotoxic and carcinogenic potency for 48 compounds in mice; most of the data were retrieved from the National Toxicology Program (NTP) database, while some additional data were retrieved from the Carcinogenic Potency Database and published studies. BMD05s (doses with 5% increase in MN frequency) were derived from MN data, and BMD10s (doses with 10% extra cancer risk) were derived from carcinogenicity data, along with their respective lower (BMDL) and upper (BMDU) confidence bounds. A clear correlation between the in vivo MN BMD05s and the cancer BMD10s was observed when the lowest BMD05 from the in vivo MN was plotted against the lowest BMD10 from the carcinogenicity data for each individual compound. By making a further selection of BMDs related to more or less equally severe cancer lesions, the correlation was considerably improved. Getting a general scientific consensus on how we can quantitatively compare different tumour lesion types and investigating the impact of MN study duration are needed to refine this correlation analysis. Nevertheless, our results suggest that a BMD derived from genotoxicity data might provide a prediction of the tumour potency (BMD10) with an uncertainty range spanning roughly a factor of 100. PMID:26163673

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

    PubMed

    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

    2014-06-01

    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

  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. PMID:26596545

  4. 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

  5. S-adenosyl-L-methionine is able to reverse micronucleus formation induced by sodium arsenite and other cytoskeleton disrupting agents in cultured human cells.

    PubMed

    Ramírez, Tzutzuy; García-Montalvo, Verónica; Wise, Carolyn; Cea-Olivares, Raymundo; Poirier, Lionel A; Herrera, Luis A

    2003-07-25

    Deficiencies of folic acid and methionine, two of the major components of the methyl metabolism, correlate with an increment of chromosome breaks and micronuclei. It has been proposed that these effects may arise from a decrease of S-adenosyl-L-methionine (SAM), the universal methyl donor. Some xenobiotics, such as arsenic, originate a reduction of SAM levels, and this is believed to alter some methylation processes (e.g. DNA methylation). The aim of the present work was to analyze the effects of exogenous SAM on the micronucleus (MN) frequency induced by sodium arsenite in human lymphocytes treated in vitro and to investigate whether these effects are related to DNA methylation. Results showed a reduction in the MN frequency in cultures treated with sodium arsenite and SAM compared to those treated with arsenite alone. To understand the mechanism by which SAM reduced the number of micronucleated cells, its effect on MN induced by other xenobiotics was also analyzed. Results showed that SAM did not have any effect on the increase in MN frequency caused by alkylating (mitomycin C or cisplatin) or demethylating agents (5-azacytidine, hydralazine, ethionine and procainamide), but it reduced the number of micronucleated cells in those treated with agents that inhibit microtubule polymerization (albendazole sulphoxide and colcemid). Since albendazole sulphoxide and colcemid inhibit microtubule polymerization, we decided to evaluate the effect of SAM on microtubule integrity. Data obtained from these evaluations showed that sodium arsenite, albendazole sulphoxide, and colcemid affect the integrity and organization of microtubules and that these effects are significantly reduced when cultures were treated at the same time with SAM. The data taken all together point out that the positive effects of SAM could be due to its ability to protect microtubules through an unknown mechanism. PMID:12873724

  6. Comparative Study of Genotoxicity in Different Tobacco Related Habits using Micronucleus Assay in Exfoliated Buccal Epithelial Cells

    PubMed Central

    Guruprasad, Yadavalli; Jose, Maji; Saxena, Kartikay; K, Deepa; Prabhu, Vishnudas

    2014-01-01

    Background: Oral cancer is one of the most debilitating diseases afflicting mankind. Consumption of tobacco in various forms constitutes one of the most important etiological factors in initiation of oral cancer. When the focus of today’s research is to determine early genotoxic changes in human cells, micronucleus (MN) assay provides a simple, yet reliable indicator of genotoxic damage. Aims and Objectives: To identify and quantify micronuclei in the exfoliated cells of oral mucosa in individuals with different tobacco related habits and control group, to compare the genotoxicity of different tobacco related habits between each group and also with that of control group. Patients and Methods: In the present study buccal smears of 135 individuals with different tobacco related habits & buccal smears of 45 age and sex matched controls were obtained, stained using Giemsa stain and then observed under 100X magnification in order to identify and quantify micronuclei in the exfoliated cells of oral mucosa. Results: The mean Micronucleus (MN) count in individuals having smoking habit were 3.11 while the count was 0.50, 2.13, and 1.67 in normal control, smoking with beetle quid and smokeless tobacco habit respectively. MN count in smokers group was 2.6 times more compared to normal controls. MN count was more even in other groups when compared to normal control but to a lesser extent. Conclusion: From our study we concluded that tobacco in any form is genotoxic especially smokers are of higher risk and micronucleus assay can be used as a simple yet reliable marker for genotoxic evaluation. PMID:24995238

  7. Evaluation of the mouse micronucleus test as compared with the in vivo cytogenics test for mutagenicity of synthetic fuel materials. Topical report

    SciTech Connect

    Not Available

    1980-03-09

    This brief topical report, provides information on a comparison of the mouse micronucleus mutagenic test proposed by a DOE contractor (FMC) for coal derived chemicals; as compared with the in vivo cytogenic test. The latter procedure is repotedly preferred by EPA authorities connected with implementation of the toxic substances control act (TOSCA). This evaluation was performed at the request of Headquarters DOE program management staff. The mouse micronucleus test takes less time and costs approximately one-fourth that of the in vivo cytogenetic procedure. This topical report is written to the extent possible in non-technical language to present conclusions associated with the evaluation rather than a detailed scientific dissertation.

  8. 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. PMID:26825076

  9. 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. PMID:26423288

  10. 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

  11. 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. PMID:26610685

  12. Incorporation of a micronucleus study into a developmental toxicology and pharmacokinetic study of L-selenomethionine in nonhuman primates

    SciTech Connect

    Choy, Wai Nang; Henika, P.R.; Willhite, C.C.; Tarantal, A.F. )

    1993-01-01

    Concomitant to a developmental toxicology study of selenium in long-tailed macaques (Macaca fascicularis), a transplacental bone marrow micronucleus assay was conducted in the fetuses of treated animals. Selenium was administered as L-selenomethionine by nasogastric intubation at 0, 150 or 300 [mu]g/kg-day to pregnant macaques daily throughout organogenesis (gestation days 20-50). Pregnancy was terminated on gestation day 100 [+-] 2 and fetuses were obtained by hysterotomy. Selenium concentrations in maternal blood were monitored throughout pregnancy and selenium concentrations in fetal blood were measured at hysterotomy. Maternal circulating selenium did not exceed 4 ppm in plasma or 3.7 ppm in erthrocytes. Selenium in cord blood was [<=] 0.1 ppm in plasma and [<=] 1.1 ppm in erthrocytes at 300 [mu]g/kg-day. Fetal bone marrow smears were prepared from the humerus and micronucleated polychromatic erythrocytes were scored. No increase of micronucleus frequency was detected in any dose group, although signs of maternal selenosis were obvious. This finding is compared to the previous observation that micronuclei were induced in the bone marrow of adult nonpregnant macaques treated at 600 [mu]g/kg-day, a lethal dose yielding blood selenium levels to 7.3 ppm in plasma and 5.7 ppm in erthyrocytes after 15 days of daily treatment, when death occurred. These data demonstrate that measurement of circulating xenobiotics can be useful for the interpretation of genetic toxicology results. 32 refs., 4 figs., 4 tabs.

  13. Safety Evaluation of Chrysanthemum indicum L. Flower Oil by Assessing Acute Oral Toxicity, Micronucleus Abnormalities, and Mutagenicity

    PubMed Central

    Hwang, Eun-Sun; Kim, Gun-Hee

    2013-01-01

    Chrysanthemum indicum is widely used to treat immune-related and infectious disorders in East Asia. C. indicum flower oil contains 1,8-cineole, germacrene D, camphor, α-cadinol, camphene, pinocarvone, β-caryophyllene, 3-cyclohexen-1-ol, and γ-curcumene. We evaluated the safety of C. indicum flower oil by conducting acute oral toxicity, bone marrow micronucleus, and bacterial reverse mutation tests. Mortality, clinical signs and gross findings of mice were measured for 15 days after the oral single gavage administration of C. indicum flower oil. There were no mortality and clinical signs of toxicity at 2,000 mg/kg body weight/day of C. indicum flower oil throughout the 15 day period. Micronucleated erythrocyte cell counts for all treated groups were not significantly different between test and control groups. Levels of 15.63~500 μg C. indicum flower oil/plate did not induce mutagenicity in S. Typhimurium and E. coli, with or without the introduction of a metabolic activation system. These results indicate that ingesting C. indicum flower oil produces no acute oral toxicity, bone marrow micronucleus, and bacterial reverse mutation. PMID:24471119

  14. 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. PMID:17487597

  15. [Genotoxic effects of pesticide-treated vegetable extracts using the Allium cepa chromosome aberration and micronucleus tests].

    PubMed

    Biscardi, D; De Fusco, R; Feretti, D; Zerbini, I; Izzo, C; Esposito, V; Nardi, G; Monarca, S

    2003-01-01

    The presence of chemical residues in vegetables and fruit is a source of human exposure to toxic and genotoxic chemicals. The mutagenic and carcinogenic action of herbicides, insecticides and fungicides on experimental animals is already known. Several studies have shown that chronic exposure to low levels of pesticides can cause adverse health effects and that many pesticides are mutagenic/carcinogenic. In the present research we monitored concurrently the presence of pesticides and genotoxic compounds extracted from 21 treated vegetables and 8 types of grapes sampled from the markets of a region in Southern Italy. The extracts were analysed for pesticides by gas-chromatography and HPLC, and for genotoxicity with two plant tests in Allium cepa roots: the micronucleus test and the chromosomal aberration test. We found 33 pesticides, some of which are outlawed. Genotoxicity was found in some of the vegetables and grapes tested. Allium cepa tests were sensitive for monitoring genotoxicity in food extracts. The micronucleus test in interphase cells gave much higher mutagenicity than the chromosomal aberration test in anaphase-telophase cells. PMID:15049565

  16. Repeated-dose liver and gastrointestinal tract micronucleus assays with CI Solvent Yellow 14 (Sudan I) using young adult rats.

    PubMed

    Matsumura, Shoji; Ikeda, Naohiro; Hamada, Shuichi; Ohyama, Wakako; Wako, Yumi; Kawasako, Kazufumi; Kasamatsu, Toshio; Nishiyama, Naohiro

    2015-03-01

    The in vivo genotoxicity of CI Solvent Yellow 14 (Sudan I) was examined using repeated-dose liver and gastrointestinal tract micronucleus (MN) assays in young adult rats. Sudan I is a mono-azo dye based on aniline and 1-amino-2-hydroxynaphthalene. This dye was demonstrated as a rat liver carcinogen in a National Toxicology Program (NTP) bioassay, and genotoxicity was noted in a rat bone marrow micronucleus (BMMN) assay. In the present study, Sudan I was administered orally to rats for 14-days, and the MN frequency in the liver, stomach, colon, and bone marrow were analyzed. The frequency of micronucleated hepatocytes (MNHEPs) was not significantly increased by the administration of the Sudan I. Gastrointestinal tract MNs were also not induced. However, in the BMMN assay, a significant increase in micronucleated immature erythrocytes (MNIMEs) was observed in a dose-dependent manner. While Sudan I has been reported to lack hepatic genotoxicity, it has also exhibited tumor-promoting activities. These results are consistent with the lack of induction of MN in the hepatocytes. The lack of MN induction in cells of the gastrointestinal tract was also logical because azo-compounds are reported to be unlikely to induce DNA damage in the rat gut. The repeated-dose rat liver and gastrointestinal tract MN assays have the potential to be used in the evaluation of the genotoxicity of a chemical in each organ in accordance with its mode of action. PMID:25892626

  17. 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

  18. 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

  19. 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

  20. 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. PMID:27321801

  1. 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

  2. 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

  3. Micronucleus and chromosome aberrations induced in onion (Allium cepa) by a petroleum refinery effluent and by river water that receives this effluent.

    PubMed

    Hoshina, Márcia M; Marin-Morales, Maria A

    2009-11-01

    In this study, micronucleus (MN) and chromosome aberration (CA) tests in Allium cepa (onion) were carried out in order to make a preliminary characterization of the water quality of the Atibaia River in an area that is under the influence of petroleum refinery and also to evaluate the effectiveness of the treatments used by the refinery. For these evaluations, seeds of A. cepa were germinated in waters collected in five different sites related with the refinery in ultra-pure water (negative control) and in methyl methanesulfonate solution (positive control). According to our results, we can suggest that even after the treatments (physicochemical, biological and stabilization pond) the final refinery effluent could induce chromosome aberrations and micronucleus in meristematic cells of A. cepa and that the discharge of the petroleum refinery effluents in the Atibaia River can interfere in the quality of this river. PMID:19647317

  4. Evaluation of Protective Effects of Bioactive Phytochemicals Against Methotrexate in Salmonella typhimurium TA1535/pSK1002 Coupled with Micronucleus Assay.

    PubMed

    Wu, Ying; Gu, Shao Bin; Li, Hao; He, Jia Yi; Li, Li; Yang, Jian Bo

    2016-02-01

    We evaluated the antimutagenic effects of 10 kinds of bioactive phytochemicals and some phytochemical combinations against methotrexate (MTX)-induced genotoxicity by the umu test in Salmonella typhimurium TA1535/pSK1002 combined with a micronucleus assay. We observed that allicin, proanthocyanidins, polyphenols, eleutherosides, and isoflavones had higher antimutagenic activities than the other five types of bioactive phytochemicals. At the highest dose tested, MTX-induced genotoxicity was inhibited by 25%-75%. Kunming mice treated by MTX along with bioactive phytochemical combinations showed significant reduction in micronucleus induction and sperm abnormality rate (P<0.01). These results indicate that bioactive phytochemical combinations can be potentially used as new cytoprotectors. PMID:27003173

  5. 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

    SciTech Connect

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

    1991-11-01

    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 As{sub 2}S{sub 3}) was inactive despite blood levels of arsenic of 300 to 900 mg/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 AsO{sub 2}{sup {minus}}. 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.

  6. Application of the comet and micronucleus assays to the detection of B[a]P genotoxicity in haemocytes of the green-lipped mussel (Perna viridis).

    PubMed

    Siu, W H L; Cao, J; Jack, R W; Wu, R S S; Richardson, B J; Xu, L; Lam, P K S

    2004-03-10

    Green-lipped mussels (Perna viridis) were exposed to water-borne benzo[a]pyrene (B[a]P) at nominal concentrations of 0, 0.3, 3 and 30 microg l(-1) for up to 12 days, and both the relative levels of DNA strand breaks (assessed using an alkaline comet assay) and the proportion of micronucleus (MN) formation were monitored in mussel haemocytes at days 0, 1, 3, 6 and 12. The results of the comet assay indicated that an increase in the proportion of strand breaks occurred generally with increasing B[a]P concentration, but a significant decrease in the levels of DNA damage was observed after exposure for 12 days at all concentrations tested, suggesting that the patterns of changes in the levels of DNA strand breakage can be explained by the threshold dependent DNA repair theory. Moreover, the relatively slow development and recovery of the DNA damage response in mussel haemocytes in comparison with previous findings utilizing P. viridis hepatopancreas suggests that the response of DNA alteration upon exposure to B[a]P may be tissue-specific in this species. Monitoring the frequency of micronucleus development in mussel haemocytes indicated both dose- and time-response relationships within the exposure period. Furthermore, the levels of DNA strand breakage correlated well with the levels of micronucleus induction, suggesting a possible cause and effect relationship between the two damage types. We suggest that DNA strand breakage and micronucleus formation in mussel haemocytes can potentially be used as convenient biomarkers of exposure to genotoxicants in the marine environment. PMID:15168946

  7. A method for the selective measurement of the radiosensitivity of quiescent cells in solid tumors--combination of immunofluorescence staining to BrdU and micronucleus assay

    SciTech Connect

    Masunaga, S.; Ono, K.; Abe, M. )

    1991-03-01

    C3H/He mice bearing the SCC VII tumor were irradiated after being given 10 injections of 5-bromo-2'-deoxyuridine (BrdU) to label all proliferating cells in the tumors, and the tumors were then excised and trypsinized. The tumor cell suspensions were incubated with cytochalasin-B (which blocks cytokinesis), and the micronucleus frequency in unlabeled cells was determined using immunofluorescence staining to BrdU. The micronucleus frequency was then used to calculate the surviving fraction of the unlabeled cells, using the regression line relating the micronucleus frequency to the surviving fraction determined separately for the total tumor cell population. Using this technique, a cell survival curve could be determined for the unlabeled cells, which were regarded as the quiescent cells. Assays performed both immediately after and 24 h after irradiation of normally-aerated tumors showed that unlabeled cells were more radioresistant and had a greater capacity for repair of potentially lethal damage than the tumor cell population as a whole. Moreover, when the assay was performed immediately after the irradiation of both normally-aerated and hypoxic tumors, it was found that unlabeled cells had a much higher hypoxic fraction than the tumor cell population as a whole. This appears to be a useful method for determining the responses of quiescent cells in solid tumors to various treatments.

  8. Activity of the human carcinogens benzidine and 2-naphthylamine in triple- and single-dose mouse bone marrow micronucleus assays: results for a combined test protocol.

    PubMed

    Mirkova, E

    1990-01-01

    The activities of the human bladder carcinogens benzidine and 2-naphthylamine in the mouse bone marrow micronucleus assays using a limited test protocol (oral dosing to male mice, sampling 24 h later) have recently been established. As a contribution to the International Collaborative Study on the evaluation of the sensitivity of the triple-dose micronucleus test protocol it was decided to re-evaluate benzidine and 2-naphthylamine using a combined triple- and single-dose test protocol. Benzidine gave a clear positive response in male mice 24 h after 3 daily doses of 150 and 300 mg/kg. A single dose of 900 mg/kg of benzidine gave a weaker response 24 h after dosing. In the case of 2-naphthylamine a stronger positive response was observed 24 h after a single dose of 600 mg/kg as compared to 3 daily doses of 200 or 400 mg/kg. There was no significant difference in the increased positive response observed for a single dose of 30 mg/kg of cyclophosphamide compared with 3 successive daily doses of 10 mg/kg. Based on the present data the combined triple/single-dose micronucleus test protocol is strongly supported. PMID:2366784

  9. 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. PMID:26866755

  10. The effect of gamma radiation on the Common carp (Cyprinus carpio): In vivo genotoxicity assessment with the micronucleus and comet assays.

    PubMed

    M K, Praveen Kumar; Soorambail K, Shyama; Bhagatsingh Harisingh, Sonaye; D'costa, Avelyno; Ramesh Chandra, Chaubey

    2015-10-01

    Radioactive wastes may be leached into freshwater, either accidentally or in industrial effluents. We have studied gamma radiation-induced DNA damage in the freshwater fish Cyprinus carpio. Fish were irradiated with 2-10Gy gamma radiation and genotoxic effects in blood cells were studied with the micronucleus (MN) and comet assays. Micronuclei and a dose-dependent increase in comet-tail DNA were seen in dose- and time-dependent studies. The highest % tail DNA was observed at 24h, declining until 72h, which may indicate the repair of radiation-induced DNA single-strand breaks after gamma radiation. However, double-stranded DNA damage may not have been repaired, as indicated by increased micronuclei at later periods. A positive correlation was observed between the comet and micronucleus assay results. This study confirms the mutagenic/genotoxic potential of gamma radiation in the Common carp, as well as the possible combined use of the micronucleus and comet assays for in vivo laboratory studies with fresh-water fish for screening the genotoxic potential of radioactive pollution. PMID:26433258

  11. 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

  12. 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

  13. Optimization of specimen preparation from formalin-fixed liver tissues for liver micronucleus assays: Hepatocyte staining with fluorescent dyes.

    PubMed

    Shigano, Miyuki; Takashima, Rie; Takasawa, Hironao; Hamada, Shuichi

    2016-04-01

    The liver micronucleus (MN) assay is an effective and important in vivo test for detecting genotoxic compounds, particularly those that require metabolic activation. For this assay, hepatocytes (HEPs) can be isolated by collagenase treatment but without requirement for in situ liver perfusion. Consequently, the liver MN assay can be integrated into a general repeated-dose (RD) toxicity study. The method is also applicable to liver MN assays involving partial hepatectomy or the use of juvenile rats. Here, we propose an improved method for staining HEPs prepared from formalin-fixed liver tissues for MN assays, without collagenase treatment. HEP suspensions are prepared by treating the tissues with concentrated KOH and a fluorescent dye, SYBR(®) Gold (SYGO), is used for staining. Visualization of the MN in SYGO-stained HEPs is clearer than with Wright-Giemsa staining. We compared the induction of MN as measured with our new method versus the conventional method using collagenase dispersion. Our method not only enables the integration of the liver MN assay into a general RD toxicity study but also allows it to be conducted retrospectively. PMID:27085473

  14. 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.

  15. Delayed Mitogenic Stimulation Decreases DNA Damage Assessed by Micronucleus Assay in Human Peripheral Blood Lymphocytes After 60Co Irradiation

    PubMed Central

    Selvan, G. Tamizh; Bhavani, M.; Vijayalakshmi, J.; Paul Solomon, F.D.; Chaudhury, N.K.; Venkatachalam, P.

    2014-01-01

    While contradictory reports are available on the yield of dicentric chromosomes (DC) in blood samples stored at different temperature and stimulated to enter into cell cycle, various times gap followed by exposure, limited information is available on the micronucleus (MN) assay. As scoring the micronuclei frequency from the blood lymphocytes of exposed individuals is an alternative to the gold standard DC assay for triage applications, we examined radiation induced MN yield in delayed mitogenic stimulation after irradiation of in vitro. Peripheral blood lymphocytes (PBL) were exposed to low LET (60Co) radiation dose (0.1 to 5Gy) and incubated at 37°C for 2, 6 and 24 hours. The MN frequency obtained in blood samples stimulated 2 hours post-irradiation showed a dose dependent increase and used to construct the dose-response curve. Further, the results also showed that blood samples stimulated twenty four hours of post-irradiation, a significant reduction (p<0.05) in MN frequencies were obtained when compared to that of blood samples stimulated two hours and six hours after post-irradiation (0.5, 1, 3 and 5Gy). The observed result suggests that the prolonged PBL storage without mitogenic stimulation could lead to interphase cell death and a delayed blood sampling could results in underestimation of dose in biological dosimetry. PMID:25249838

  16. Chromosome aberration and micronucleus frequencies in Allium cepa cells exposed to petroleum polluted water--a case study.

    PubMed

    Leme, Daniela Morais; Marin-Morales, Maria Aparecida

    2008-01-31

    In the present study, we applied Chromosome Aberration (CA) and Micronucleus (MN) tests to Allium cepa root cells, in order to evaluate the water quality of Guaecá river. This river, located in the city of São Sebastião, SP, Brazil, had been affected by an oil pipeline leak. Chemical analyses of Total Petroleum Hydrocarbons (TPHs) and Polycyclic Aromatic Hydrocarbons (PAHs) were also carried out in water samples, collected in July 2005 (dry season) and February 2006 (rainy season) in 4 different river sites. The largest CA and MN incidence in the meristematic cells of A. cepa was observed after exposure to water sample collected during the dry season, at the spring of the river, where the oil leak has arisen. The F(1) cells from roots exposed to such sample (non-merismatic region) were also analyzed for the incidence of MN, showing a larger frequency of irregularities, indicating a possible development of CA into MN. Lastly, our study reveals a direct correlation between water chemical analyses (contamination by TPHs and PAHs) and both genotoxic and mutagenic effects observed in exposed A. cepa cells. PMID:18068420

  17. Application of the micronucleus and comet assays to mussel Dreissena polymorpha haemocytes for genotoxicity monitoring of freshwater environments.

    PubMed

    Klobucar, Göran I V; Pavlica, Mirjana; Erben, Radovan; Papes, Drazena

    2003-06-19

    Assessment of DNA damage is of primary concern when determining the pollution-related stress in living organisms. To monitor genotoxicity of the freshwater environments we used micronucleus (MN) and comet assay on Dreissena polymorpha haemocytes. Caged mussels, collected from the river Drava, were transplanted to four monitoring sites of different pollution intensity in the river Sava. Exposition lasted for a month. The baseline level of MN frequencies in the haemocytes of mussels from reference site (river Drava) was 0.5 per thousand. No increase in MN frequency was found in mussels from the medium-polluted site (Zagreb) in the river Sava while other, more polluted sites showed higher MN frequencies ranging from 2.7 per thousand (Lukavec) and 3.1 per thousand (Oborovo) to 5.2 per thousand (Sisak). Results from comet assay showed concordance with MN assay in indicating intensity of DNA damage. The use of haemocytes from caged, non-indigenous mussels in MN and comet assay proved to be a sensitive tool for the freshwater genotoxicity monitoring. PMID:12763672

  18. 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. PMID:24743767

  19. 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.

  20. 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. PMID:25907664

  1. Vanadium pentoxide-coated ultrafine titanium dioxide particles induce cellular damage and micronucleus formation in V79 cells.

    PubMed

    Bhattacharya, K; Cramer, H; Albrecht, C; Schins, R; Rahman, Q; Zimmermann, U; Dopp, E

    2008-01-01

    Surface-treated titanium dioxide (TiO(2)) particles coated with vanadium pentoxide (V(2)O(5)) are used industrially for selective catalytic reactions such as the removal of nitrous oxide from exhaust gases of combustion power plants (SCR process) and in biomaterials for increasing the strength of implants. In the present study, untreated ultrafine TiO(2) particles (anatase, diameter: 30-50 nm) and vanadium pentoxide (V(2)O(5))-treated anatase particles were tested for their cyto- and genotoxic effects in V79 cells (hamster lung fibroblasts). Cytotoxic effects of the particles were assessed by trypan blue exclusion, while genotoxic effects were investigated by micronucleus (MN) assay. In addition, the generation of reactive oxygen species (ROS) was determined by the acellular method of electron spin resonance technique (ESR) and by the cellular technique of determination of thiobarbituric acid-reactive substances (TBARS). Our results demonstrate that V(2)O(5)-treated TiO(2) particles induce more potent cyto- and genotoxic effects than untreated particles. Further, acellular and cellular radical formation was more pronounced with V(2)O(5)-anatase than untreated anatase. Thus, data indicate that V(2)O(5)-treated TiO(2) particles were more reactive than natural anatase and capable of inducing DNA damage in mammalian cells through production of free radicals. PMID:18569605

  2. Micronucleus assay assessment of possible genotoxic effects in patients treated with titanium alloy endosseous implants or miniplates.

    PubMed

    Karahalil, Bensu; Kadioglu, Ela; Tuzuner-Oncul, Ayşegül M; Cimen, Emre; Emerce, Esra; Kisnisci, Reha S

    2014-01-15

    The use of titanium and its alloys (Ti-6Al-4V) for oral surgery has increased dramatically in recent years. Ti is a stable biocompatible metal suitable for oral applications and it has been used for endosseous subperiosteal implants and miniplate fixation for more than 25 years. Dental implants are typically made of Ti or Ti alloys. The alloys are potentially toxic due to release of vanadium and aluminum. We tested the possible genotoxicity of Ti alloy endosseous implants and miniplates on the oral mucosal tissues of two groups of patients: 17 patients receiving Ti miniplate and screw fixation, and 37 endosseous dental implant placement patients. Preoperative and postoperative mucogingival cell samples were collected. Genotoxicity was assessed by the micronucleus assay (MN). There were slight but not statistically significant increases in the frequencies of MN (p=0.087 and p=0.047) post-operation in both groups. In summary, neither of the applications showed genotoxicity in the oral epithelial cells of patients. PMID:24189049

  3. Genetic damage in soybean workers exposed to pesticides: evaluation with the comet and buccal micronucleus cytome assays.

    PubMed

    Benedetti, Danieli; Nunes, Emilene; Sarmento, Merielen; Porto, Carem; Dos Santos, Carla Eliete Iochims; Dias, Johnny Ferraz; da Silva, Juliana

    2013-04-15

    Soybean cultivation is widespread in the State of Rio Grande do Sul (RS, Brazil), especially in the city of Espumoso. Soybean workers in this region are increasingly exposed to a wide combination of chemical agents present in formulations of fungicides, herbicides, and insecticides. In the present study, the comet assay in peripheral leukocytes and the buccal micronucleus (MN) cytome assay (BMCyt) in exfoliated buccal cells were used to assess the effects of exposures to pesticides in soybean farm workers from Espumoso. A total of 127 individuals, 81 exposed and 46 non-exposed controls, were evaluated. Comet assay and BMCyt (micronuclei and nuclear buds) data revealed DNA damage in soybean workers. Cell death was also observed (condensed chromatin, karyorhectic, and karyolitic cells). Inhibition of non-specific choline esterase (BchE) was not observed in the workers. The trace element contents of buccal samples were analyzed by Particle-Induced X-ray Emission (PIXE). Higher concentrations of Mg, Al, Si, P, S, and Cl were observed in cells from workers. No associations with use of personal protective equipment, gender, or mode of application of pesticides were observed. Our findings indicate the advisability of monitoring genetic toxicity in soybean farm workers exposed to pesticides. PMID:23347873

  4. 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. PMID:23055270

  5. 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. PMID:24849678

  6. 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.

  7. Occupational exposure to formaldehyde: genotoxic risk evaluation by comet assay and micronucleus test using human peripheral lymphocytes.

    PubMed

    Costa, Solange; Pina, Carolina; Coelho, Patrícia; Costa, Carla; Silva, Susana; Porto, Beatriz; Laffon, Blanca; Teixeira, João Paulo

    2011-01-01

    Formaldehyde (FA) is a world high-production compound with numerous applications ranging from production of resins to medicines. Due to its sensitizing properties, irritating effects and potential cancer hazard FA is of great environmental health concern. Numerous studies in humans and experimental animals demonstrated that inhaled FA produced toxicity, genotoxicity, and cancer at distal sites. IARC, based on sufficient data, reclassified FA as a human carcinogen. The highest level of human exposure to this aldehyde occurs in occupational settings, namely, in pathology and anatomy laboratories, where FA is commonly used as a fixative and tissue preservative. Several studies consistently showed that the levels of airborne FA in anatomy laboratories exceeded recommended exposure criteria. In order to assess the genotoxic effects of chronic occupational exposure to FA, a group of pathology/anatomy workers was assessed using a micronucleus (MN) test and comet assay. The level of exposure to FA was also determined and the time-weighted average (TWA) of exposure was calculated for each subject. The TWA mean value for FA exposed workers was 0.43 ± 0.06 ppm, exceeding national and international recommended limit levels of 0.3 ppm. Both MN frequency and comet assay parameters were significantly higher in exposed subjects. Data obtained confirm a correlation between genetic damage and occupational exposure to FA. These data, along with recent implications of human carcinogenicity, point out the need for close monitoring of occupational exposure to FA. Implementation of security and hygiene measures as well as good practices campaigns may be crucial to decrease risk. PMID:21707428

  8. Comparison of in vitro and in vivo clastogenic potency based on benchmark dose analysis of flow cytometric micronucleus data.

    PubMed

    Bemis, Jeffrey C; Wills, John W; Bryce, Steven M; Torous, Dorothea K; Dertinger, Stephen D; Slob, Wout

    2016-05-01

    The application of flow cytometry as a scoring platform for both in vivo and in vitro micronucleus (MN) studies has enabled the efficient generation of high quality datasets suitable for comprehensive assessment of dose-response. Using this information, it is possible to obtain precise estimates of the clastogenic potency of chemicals. We illustrate this by estimating the in vivo and the in vitro potencies of seven model clastogenic agents (melphalan, chlorambucil, thiotepa, 1,3-propane sultone, hydroxyurea, azathioprine and methyl methanesulfonate) by deriving BMDs using freely available BMD software (PROAST). After exposing male rats for 3 days with up to nine dose levels of each individual chemical, peripheral blood samples were collected on Day 4. These chemicals were also evaluated for in vitro MN induction by treating TK6 cells with up to 20 concentrations in quadruplicate. In vitro MN frequencies were determined via flow cytometry using a 96-well plate autosampler. The estimated in vitro and in vivo BMDs were found to correlate to each other. The correlation showed considerable scatter, as may be expected given the complexity of the whole animal model versus the simplicity of the cell culture system. Even so, the existence of the correlation suggests that information on the clastogenic potency of a compound can be derived from either whole animal studies or cell culture-based models of chromosomal damage. We also show that the choice of the benchmark response, i.e. the effect size associated with the BMD, is not essential in establishing the correlation between both systems. Our results support the concept that datasets derived from comprehensive genotoxicity studies can provide quantitative dose-response metrics. Such investigational studies, when supported by additional data, might then contribute directly to product safety investigations, regulatory decision-making and human risk assessment. PMID:26049158

  9. 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. PMID:27090695

  10. SFTG international collaborative study on in vitro micronucleus test I. General conditions and overall conclusions of the study.

    PubMed

    Lorge, Elisabeth; Thybaud, Veronique; Aardema, Marilyn J; Oliver, Jo; Wakata, Akihiro; Lorenzon, Giocondo; Marzin, Daniel

    2006-08-01

    the in vitro micronucleus test. PMID:16815079

  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. PMID:25370840

  12. 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

  13. Biomonitoring of water genotoxicity in a Conservation Unit in the Sinos River Basin, Southern Brazil, using the Tradescantia micronucleus bioassay.

    PubMed

    Endres Júnior, D; Sasamori, M H; Cassanego, Mbb; Droste, A

    2015-05-01

    The Tradescantia micronucleus (Trad-MCN) bioassay was used to investigate genotoxicity of water bodies in the Parque Municipal Henrique Luís Roessler (PMHLR), a conservation unit in the city of Novo Hamburgo, Southern Brazil, from November 2010 to October 2011. Every month, cuttings with young inflorescences of Tradescantia pallida var. purpurea were exposed for 24 hours to water collected at three sites in the park: (S1) head of the main stream; (S2) head of a secondary stream; (S3) a point past the junction of the two water bodies in which S1 and S2 were located. As a negative control, cuttings were exposed to distilled water for 24 h every quarter. Micronuclei (MCN) frequency was determined in young tetrads of pollen mother cells and described as MCN/100 tetrads. Rainfall data were also recorded. In nine months at S1 and S2, and in eleven months at S3, micronuclei frequencies were significantly higher than in quarterly controls, in which frequencies varied from 1.19 to 1.62. During sampling, no significant differences were found in MCN frequencies at S1, which ranged from 2.2 to 3.6. At the other sampling sites, there were significant differences between the months evaluated, and MCN frequencies ranged from 1.3 to 6.5 at S2 and from 2.3 to 5.2 at S3. There were no associations between rainfall and MCN frequencies at the three sampling sites. Tradescantia pallida var. purpurea confirmed genotoxicity in the water bodies of the PMHLR, even at the head of the streams, which suggests that actions should be promoted to control anthropogenic effects in the streams of this conservation unit. PMID:26270220

  14. Increased micronucleus frequencies in surrogate and target cells from workers exposed to crystalline silica-containing dust.

    PubMed

    Demircigil, Gonca Cakmak; Coskun, Erdem; Vidinli, Nuri; Erbay, Yildiray; Yilmaz, Metin; Cimrin, Arif; Schins, Roel P; Borm, Paul J; Burgaz, Sema

    2010-03-01

    Mining, crushing, grinding, sandblasting and construction are high-risk activities with regard to crystalline silica exposure, especially in developing countries. Respirable crystalline silica (quartz and cristobalite) inhaled from occupational sources has been reclassified as a human carcinogen in 1997 by the International Agency for Research on Cancer. However, the biological activity of crystalline silica has been found to be variable among different industries, and this has formed the basis for further in vivo/in vitro mechanistic research and epidemiologic studies. This study was conducted for genotoxicity evaluation in a population of workers (e.g. glass industry workers, sandblasters, and stone grinders) mainly exposed to crystalline silica in four different workplaces in Turkey. The micronucleus (MN) assay was applied both in peripheral blood lymphocytes (PBL) as a surrogate tissue and in nasal epithelial cells (NEC) as a target tissue of the respiratory tract. Our study revealed significantly higher MN frequencies in the workers (n = 50) versus the control group (n = 29) (P < 0.001) and indicated a significant effect of occupational exposure on MN induction in both of the tissues. For the NEC target tissue, the difference in MN frequencies between the workers and control group was 3-fold, whereas in peripheral tissue, it was 2-fold. Respirable dust and crystalline silica levels exceeding limit values and mineralogical/elemental dust composition of the dust of at least 70% SiO(2) were used as markers of crystalline silica exposure in each of the workplaces. Moreover, 24% of the current workers were found to have early radiographical changes (profusion category of 1). In conclusion, although the PBL are not primary target cells for respiratory particulate toxicants, an evident increase in MN frequencies in this surrogate tissue was observed, alongside with a significant increase in NEC and may be an indicator of the accumulated genetic damage associated with

  15. Repeated dose liver and gastrointestinal tract micronucleus assays using N-methyl-N'-nitro-N-nitrosoguanidine in young adult rats.

    PubMed

    Takayanagi, Tomomi; Wako, Yumi; Kawasako, Kazufumi; Hori, Hisako; Fujii, Wataru; Ohyama, Wakako

    2015-03-01

    N-Methyl-N'-nitro-N-nitrosoguanidine (MNNG) is a direct-acting mutagen that induces tumors in the glandular stomach, but not in the liver or colon, of rats after oral administration. To evaluate the performance of repeated dose liver and gastrointestinal tract micronucleus (MN) assays in young adult rats, MNNG was administered by oral gavage to male CD (SD) rats aged 6 weeks at doses of 0 (vehicle; 2.5% DMSO aqueous solution), 3.125, 6.25, 12.5, and 25mg/kg/day once daily for 14 and 28 days, and the MN frequencies were examined in the hepatocytes, glandular stomach cells, and colonic cells. The MN induction in immature erythrocytes in the bone marrow of these animals was also simultaneously evaluated. The frequencies of micronucleated (MNed) glandular stomach cells were significantly increased in all MNNG treatment groups in a dose-dependent manner in both repeated dose studies. In contrast, the frequencies of MNed hepatocytes and colonic cells were not significantly increased compared to the vehicle control. In the bone marrow, a small but significant increase in the frequency of MNed immature erythrocytes was observed only at the highest dose in the 28-day study. Since a clear positive result in the glandular stomach agrees with the tissue specificity of tumor induction by this chemical, the MN assay with the glandular stomach, which is a direct contact site with high concentrations of test substances administered by oral gavage, may be useful for detecting genotoxic compounds that are short-lived in vivo, such as MNNG. PMID:25892628

  16. Assessment of the in vivo genotoxicity of isomers of dinitrotoluene using the alkaline Comet and peripheral blood micronucleus assays.

    PubMed

    Lent, Emily May; Crouse, Lee C B; Quinn, Michael J; Wallace, Shannon M

    2012-02-18

    Dinitrotoluene (DNT) is a nitroaromatic explosive that exists as six isomers; two major isomers (2,4- and 2,6-DNT) and four minor isomers (2,3-, 2,5-, 3,4-, and 3,5-DNT). DNT has been found in soil, surface water, and groundwater near ammunition production plants. The major isomers of DNT are classified as "likely to cause cancer in humans."In vitro studies have provided conflicting data regarding the genotoxicity of the minor isomers. Studies indicate that metabolism in the gut and liver are necessary to convert DNT to genotoxic compounds. As such, in the present study the genotoxicity of isomers of DNT was assessed using two in vivo genotoxicity assays. The Comet assay was used to detect DNA damage in liver cells from male Sprague-Dawley rats following oral exposure (14-day) to individual isomers of DNT. The micronucleus assay was conducted using flow cytometric analysis to detect chromosomal damage in peripheral blood. Treatment with 2,3-, 3,4-, 2,4-, 2,5- and 3,5-DNT did not induce DNA damage in liver cells or increase the frequency of micronucleated reticulocytes (MN-RET) in peripheral blood at the doses tested. Treatment with 2,6-DNT induced DNA damage in liver tissue at all doses tested, but did not increase the frequency of micronucleated reticulocytes (MN-RET) in peripheral blood. Thus, 2,4-DNT and the minor isomers were not genotoxic under these test conditions, while 2,6-DNT was genotoxic in the target tissue, the liver. These results support previous research which indicated that the hepatocarcinogenicity of technical grade DNT (TG-DNT) could be attributed to the 2,6-DNT isomer. PMID:22155124

  17. 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). PMID:26443842

  18. The micronucleus assay in mammalian cells in vitro to assess health benefits of various phytochemicals.

    PubMed

    Meschini, Roberta; Berni, Andrea; Filippi, Silvia; Pepe, Gaetano; Grossi, Maria Rosaria; Natarajan, Adayapalam T; Palitti, Fabrizio

    2015-11-01

    We evaluated the protective effects of Gentiana lutea extracts (GLEx) and 6-Gingerol (6-G) on clastogenicity of N-methyl-N'-nitro-N-nitrosoguanidine (MNNG) and 7,12-dimethylbenz(α) anthracene (DMBA) in vitro on HepG2 cells using the frequencies of induced micronuclei (MN) as the end point. Pre-, post- and simultaneous treatments with GLEx or 6-G and the carcinogens were carried out. Both GLEx post- and simultaneous treatments reduced the frequencies of MN induced by MNNG and DMBA. Probably this effect is due to an increase of cytostasis and a physico-chemical interaction between GLEx and DMBA under simultaneous treatment. Pre- and simultaneous treatments with 6-G significantly reduced the yield of MNNG-induced micronuclei without affecting % of cytostasis. Simultaneous treatment with 6-G plus DMBA resulted in reduction in the frequency of MN and an increase in cytotoxicity compared to sample treated alone with DMBA, whereas a post-treatment, caused a significant decrease in the yield of MN compared with DMBA alone without any cytotoxic effect. These results are compared with our earlier data obtained in the same system with other phytochemicals. It is concluded that for a critical evaluation of the protective effects of phytochemicals, both the influence on the induced MN and induced cytostasis have to be considered. PMID:26520376

  19. 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. PMID:23706883

  20. 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

  1. Seed germination, root elongation, root-tip mitosis, and micronucleus induction of five crop plants exposed to chromium in fluvo-aquic soil.

    PubMed

    Hou, Jing-; Liu, Guan-Nan; Xue, Wei; Fu, Wen-Jun; Liang, Bao-Cui; Liu, Xin-Hui

    2014-03-01

    The present study aimed to determine the toxic effects of chromium (Cr) on cabbage (Brassica oleracea), cucumber (Cucumis sativus), lettuce (Lactuca sativa), wheat (Triticum aestivum), and corn (Zea mays), and identify the sensitive plant species and appropriate bioassays for potential use in phytotoxicity assessment of Cr in soil. Results showed that seed germination might not be a sensitive assay for assessing Cr toxicity because at most of the Cr levels there were no toxic effects. Root elongation was more sensitive to Cr than seed germination. The lowest concentration of adverse effect (LOAEC) of lettuce was 20 mg Cr/kg(-1) soil, and that of the other 4 species was 50 mg Cr/kg(-1) soil. The mitotic index fluctuated with increasing Cr concentration, thus it was insufficient to assess toxicity of Cr in soil. However, micronucleus assay showed that 5 mg Cr/kg(-1) soil caused a significant increase in micronucleus frequency in cabbage, cucumber, and lettuce. For wheat and corn, however, the LOAEC was 20 and 50 mg/Cr/kg(-1) soil, respectively. Furthermore, the analysis of Cr accumulation showed that lettuce significantly accumulated Cr for all the tested concentrations. However, corn and wheat significantly accumulated Cr only with the highest tested dose. This may explain the higher inhibitory effects of Cr on root growth. It can be concluded that root elongation and micronucleus assay are good indicators to assess the phytotoxicity of Cr in soil. Lettuce is the most sensitive species for indicating the toxicity of Cr in soil. PMID:24318542

  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. [Mutagenic effect of pesticides fastac 10 EK and durs ban 4E studied in a micronucleus test iin mouse bone marrow cells].

    PubMed

    Benova, D K; Rupova, I M; Iagova, A Kh; Bineva, M V

    1989-12-01

    The mutagenic activity of vastak and durs ban pesticides was studied by the micronucleus test in mouse bone marrow. The frequency of micronuclei in polychromatic erythrocytes was tested at 24, 36 and 42 h after oral administration of 50% LD50 dose of vastak (14 mg/kg) and durs ban (30.5 mg/kg). Significantly different increase in micronucleated polychromatic erythrocytes was established at 24, 36 and 48 h after vastak administration, and at 24 and 36 h after durs ban treatment. Doses of 25% LD50 for both pesticides showed no mutagenic activity, as judged by the induction of micronuclei in polychromatic erythrocytes. PMID:2483930

  4. Development of a High-Throughput and Miniaturized Cytokinesis-Block Micronucleus Assay for Use as a Biological Dosimetry Population Triage Tool

    PubMed Central

    Lue, Stanley W.; Repin, Mikhail; Mahnke, Ryan; Brenner, David J.

    2015-01-01

    Biodosimetry is an essential tool for providing timely assessments of radiation exposure. For a large mass-casualty event involving exposure to ionizing radiation, it is of utmost importance to rapidly provide dose information for medical treatment. The well-established cytokinesis-block micronucleus (CBMN) assay is a validated method for biodosimetry. However, the need for an accelerated sample processing is required for the CBMN assay to be a suitable population triage tool. We report here on the development of a high-throughput and miniaturized version of the CMBN assay for accelerated sample processing. PMID:26230078

  5. Investigation of micronucleus induction in MTH1 knockdown cells exposed to UVA, UVB or UVC.

    PubMed

    Fotouhi, Asal; Cornella, Nicola; Ramezani, Mehrafarin; Wojcik, Andrzej; Haghdoost, Siamak

    2015-11-01

    The longer wave parts of UVR can increase the production of reactive oxygen species (ROS) which can oxidize nucleotides in the DNA or in the nucleotide pool leading to mutations. Oxidized bases in the DNA are repaired mainly by the DNA base excision repair system and incorporation of oxidized nucleotides into newly synthesized DNA can be prevented by the enzyme MTH1. Here we hypothesize that the formation of several oxidized base damages (from pool and DNA) in close proximity, would cause a high number of base excision repair events, leading to DNA double strand breaks (DSB) and therefore giving rise to cytogenetic damage. If this hypothesis is true, cells with low levels of MTH1 will show higher cytogenetic damage after the longer wave parts of UVR. We analyzed micronuclei induction (MN) as an endpoint for cytogenetic damage in the human lymphoblastoid cell line, TK6, with a normal and a reduced level of MTH1 exposed to UVR. The results indicate a higher level of micronuclei at all incubation times after exposure to the longer wave parts of UVR. There is no significant difference between wildtype and MTH1-knockdown TK6 cells, indicating that MTH1 has no protective role in UVR-induced cytogenetic damage. This indicates that DSBs induced by UV arise from damage forms by direct interaction of UV or ROS with the DNA rather than through oxidation of dNTP. PMID:26520386

  6. 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

  7. The in vivo erythrocyte micronucleus test: measurement at steady state increases assay efficiency and permits integration with toxicity studies.

    PubMed

    MacGregor, J T; Wehr, C M; Henika, P R; Shelby, M D

    1990-04-01

    The mouse erythrocyte micronucleus assay has been traditionally carried out using one or two exposures to the test agent, followed by sampling at two or three postexposure times to obtain a sample near the time of the transient peak of micronucleated polychromatic erythrocytes (PCEs). We have demonstrated that frequencies of micronucleated RNA-positive (PCEs) and RNA-negative erythrocytes in blood and bone marrow come to steady state during "continuous" exposure via diet or drinking water, or during repeated daily exposures to test agents by ip injection, gavage, or inhalation. Under these exposure conditions, frequencies of micronucleated cells in peripheral blood approached steady state within 2-3 days in RNA-positive erythrocytes and in 5-6 weeks in RNA-negative erythrocytes. With exposure durations of 6 days (monocrotaline or Crotalaria seeds in diet), 10 days (triethylenemelamine, mitomycin C, 7,12-dimethylbenzanthracene, or colchicine, ip daily), 90 days (triethylenemelamine or urethan in drinking water or 1,3-butadiene via inhalation), or 2 years (benezene by daily gavage), frequencies of micronucleated cells attained and remained at steady state for prolonged periods. At steady state, frequencies of micronucleated RNA-positive cells in bone marrow samples were similar to those in RNA-positive and RNA-negative cells in peripheral blood (e.g., triethylenemelamine in drinking water at 4 micrograms/ml resulted in frequencies of micronucleated RNA-negative erythrocytes in peripheral blood of 27/1000 after 45 days of exposure and 24/1000 after 90 days, with a frequency of 28/1000 in bone marrow RNA-positive erythrocytes after 90 days). The data suggest that the efficiency of the assay would be markedly improved by using a repeated dose schedule with a single sample taken at steady state, rather than scoring multiple samples at various times after a single dose. This approach allows the frequency of micronucleated cells to be measured in a sample of bone marrow or

  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. PMID:24688298

  9. 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

  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. PMID:26720589

  11. 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. PMID:26212304

  12. 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

    2015-01-01

    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. PMID:26782493

  13. UDP-glucuronosyltransferase-mediated protection against in vitro DNA oxidation and micronucleus formation initiated by phenytoin and its embryotoxic metabolite 5-(p-hydroxyphenyl)-5-phenylhydantoin.

    PubMed

    Kim, P M; Winn, L M; Parman, T; Wells, P G

    1997-01-01

    UDP-Glucuronosyltransferases (UGTs) are important in the elimination of most xenobiotics, including 5-(p-hydroxyphenyl)-5-phenylhydantoin (HPPH), the major, reputedly nontoxic, metabolite of the anticonvulsant drug phenytoin. However, HPPH alternatively may be bioactivated by peroxidases, such as prostaglandin H synthase, to a reactive intermediate that initiates DNA oxidation (reflected by 8-hydroxy-2'-deoxyguanosine), genotoxicity (reflected by micronuclei) and embryopathy. This hypothesis was evaluated in skin fibroblasts cultured from heterozygous (+/j) and homozygous (j/j) UGT-deficient Gunn rats and in mouse embryo culture, with confirmation of direct NG-glucuronidation of phenytoin in Gunn rats in vivo. HPPH (80 microM) increased micronuclei by 2.0-, 4.8- and 4.6-fold in +/+ UGT-normal cells (P = .03) and +/j and j/j UGT-deficient cells (P = .0001), respectively. HPPH-initiated micronucleus formation was increased 3.0- and 3.4-fold in +/j (P = .02) and j/j (P = .04) UGT-deficient cells, respectively, vs. +/+ UGT-normal cells. Micronuclei were not initiated by 10 microM HPPH in +/+ UGT-normal cells but were increased by 4- and 3.8-fold in +/j and j/j UGT-deficient cells (P = .0001), respectively, and were increased 2.7- and 3.0-fold in +/j (P = .007) and j/j (P = .0002) UGT-deficient cells, respectively, vs. +/+ UGT-normal cells. 8-Hydroxy-2'-deoxyguanosine was increased in j/j UGT-deficient but not +/+ UGT-normal cells treated with 80 microM HPPH (P < .05). The embryopathic potency of 80 microM HPPH in embryo culture, reflected by decreases in anterior neuropore closure, turning, yolk sac diameter and crown-rump length (P < .05), was equivalent to that reported for phenytoin. Phenytoin (80 microM) enhanced micronucleus formation 1.7-, 4.4- and 3.8-fold in +/+ cells (P = .03) and +/j and j/j UGT-deficient cells (P = .0001), respectively. Phenytoin-initiated micronucleus formation was increased about 4-fold in both +/j (P = .006) and j/j (P = .009) UGT

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

    PubMed Central

    Rim, Kyung-Taek; Kim, Soo-Jin

    2015-01-01

    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. PMID:26929826

  15. Lack of Mutagenicity Potential of Periploca sepium Bge. in Bacterial Reverse Mutation (Ames) Test, Chromosomal Aberration and Micronucleus Test in Mice

    PubMed Central

    Zhang, Mei-Shu; Bang, In-Seok

    2012-01-01

    Objectives The root barks of Periploca sepium Bge. (P. sepium) has been used in traditional Chinese medicine for healing wounds and treating rheumatoid arthritis. However, toxicity in high-doses was often diagnosed by the presence of many glycosides. The potential mutagenicity of P. sepium was investigated both in vitro and in vivo. Methods This was examined by the bacterial reverse mutation (Ames) test using Escherichia coli WP2uvrA and Salmonella typhimurium strains, such as TA98, TA100, TA1535, and TA1537. Chromosomal aberrations were investigated using Chinese hamster lung cells, and the micronucleus test using mice. Results P. sepium did not induce mutagenicity in the bacterial test or chromosomal aberrations in Chinese hamster lung cells, although metabolic activation and micronucleated polychromatic erythrocytes were seen in the mice bone marrow cells. Conclusions Considering these results, it is suggested that P. sepium does not have mutagenic potential under the conditions examined in each study. PMID:22888473

  16. 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. PMID:26929826

  17. The micronucleus test and erythropoiesis. Effects of erythropoietin and a mutagen on the ratio of polychromatic to normochromatic erythrocytes (P/N ratio).

    PubMed

    Suzuki, Y; Nagae, Y; Li, J; Sakaba, H; Mozawa, K; Takahashi, A; Shimizu, H

    1989-11-01

    It is considered that a decrease of the ratio of polychromatic erythrocytes (PCE) to normochromatic erythrocytes (NCE) (P/N) in the micronucleus test is an indicator of bone marrow toxicity induced by mutagens. However, the exact meaning of fluctuation in the P/N ratio is not yet known. We have studied this point by counting the total number of erythrocytes and nucleated cells in the bone marrow following various treatments. The P/N ratio decreased gradually with time after administration of mitomycin C. Our data suggest that the decrease of P/N ratio was attributable to an increase in the numbers of the denominator, i.e. NCE, caused by rapid differentiation and multiplication or denucleation of erythroblasts which remained in the bone marrow instead of entering the peripheral blood stream. A decrease of P/N ratio was also observed in the early phase after administration of erythropoietin, an agent which induces differentiation and multiplication of erythroblasts. This phenomenon might result from an increase of PCE delivery into the blood circulation. However, following the initial decrease, the P/N ratio increased gradually 48 h after administration of erythropoietin. It is supposed that this increase probably resulted from an increase in PCE in the bone marrow due to the direct effects of erythropoietin on erythropoiesis. The drastic change in erythropoiesis in the bone marrow induced by either mutagen or erythropoietin treatment will affect the fluctuations of the P/N ratio or the number of micronucleated erythrocytes per non-micronucleated erythocytes in the micronucleus test. This contrasts with the original explanation for such fluctuations which attributed them to replenishment of the marrow by peripheral blood. PMID:2516221

  18. 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.

  19. Comparative activity of human carcinogens and NTP rodent carcinogens in the mouse bone marrow micronucleus assay: an integrative approach to genetic toxicity data assessment.

    PubMed Central

    Tinwell, H; Ashby, J

    1994-01-01

    The mouse bone marrow micronucleus (MN) assay holds a key position in all schemes for detecting potential human carcinogens and mutagens. It was therefore of concern when Shelby et al. reported that only 5 of 25 rodent carcinogens defined by the U.S. NTP were positive in the assay. Further, each of these positive responses was weak and indistinguishable from the 4 positive responses observed among the 24 NTP noncarcinogens tested. To focus these findings, the activity in the MN assay of 26 human carcinogens, 6 reference rodent genotoxins, and the 9 NTP chemicals positive in the MN assay have been displayed in a common format. This involved plotting the minimum positive dose level (expressed as mumole/kilogram) and the maximum fold-increase in micronucleated polychromatic erythrocytes frequency observed at any dose level. By displaying the high sensitivity of the micronucleus assay to the reference human and rodent genotoxins, this analysis emphasizes the weakness in the MN assay responses given by the NTP carcinogens reported by Shelby et al. This, in turn, poses questions about the intrinsic hazard of this selection of NTP rodent carcinogens. Using fotemustine and vitamin C as models of a toxic and a nontoxic chemical known to be active in the MN assay, this analysis describes a method by which their relative potential human hazard can be distinguished (a synthetic, as opposed to an analytical approach to data assessment). The possibility that some weak responses observed in the MN assay at elevated dose levels may be stress induced is considered. Images p758-a Figure 1. PMID:9657707

  20. Validating high-throughput micronucleus analysis of peripheral reticulocytes for radiation biodosimetry: benchmark against dicentric and CBMN assays in a mouse model.

    PubMed

    Chen, Yuhchyau; Tsai, Ying; Nowak, Irena; Wang, Nancy; Hyrien, Ollivier; Wilkins, Ruth; Ferrarotto, Catherine; Sun, Hongliang; Dertinger, Stephen D

    2010-02-01

    Automation of radiation biodosimetry is one of the top priority tasks considered by the Office of Science and Technology Policy and the Homeland Security Council in preparation for the nation's readiness for a possible radionuclear terrorist attack. The Center for Biophysical Assessment and Risk Management Following Irradiation, a consortium of researchers and institutions centered at the University of Rochester, has been investigating automated scoring of radiation-induced micronucleus formation in reticulocytes for high-throughput radiation biodosimetry. The collaborative project is based on a commercially-available product by Litron Laboratories in Rochester, New York. The study was designed to validate the flow-cytometry based analysis of micronucleated reticulocyte expression for radiation biodosimetry by benchmarking against the standard lymphocyte-based biodosimetry methods in a mouse model. C57B1/6 mice and C3H mice were exposed to Cs total-body radiation from 0-3 Gy. Blood samples were subsequently analyzed for CD71+ micronucleated reticulocyte and reticulocyte frequencies by flow cytometry. Results showed a linear dose-response of MN-RET up to 1 Gy for C57B1/6 and 2 Gy for C3H mice. On the other hand, robust and good dose-response curves were obtained with lymphocyte-based dicentric assay and cytokinesis-block micronucleus assay up to 3 Gy. High-throughput, automated analyses of micronucleated reticulocytes is a sensitive and reproducible method for detecting recent radiation exposure. In mice, the dose range of detection is useful up to 1 Gy (C57Bl/6) and 2 Gy (C3H) but not reliable beyond these dose limits. The utilization of this automated analysis for human radiation biodosimetry is currently under investigation. PMID:20065686

  1. The reconstructed skin micronucleus assay in EpiDerm™: reduction of false-positive results - a mechanistic study with epigallocatechin gallate.

    PubMed

    Yuki, Katsuyuki; Ikeda, Naohiro; Nishiyama, Naohiro; Kasamatsu, Toshio

    2013-10-01

    The high rate of false-positive or misleading results in in vitro mammalian genotoxicity testing is a hurdle in the development of valuable chemicals, especially those used in cosmetics, for which in vivo testing is banned in the European Union. The reconstructed skin micronucleus (RSMN) assay in EpiDerm™ (MatTek Corporation, USA) has shown promise as a follow-up for positive in vitro mammalian genotoxicity tests. However, few studies have explored its better predictive performance compared with existing in vitro assays. In the present study, we followed the protocol of the RSMN assay and used eight chemicals to compare micronucleus (MN) induction with EpiDerm™ with that in normal human epidermal keratinocytes (NHEKs), both derived from human skin. The assessments of EpiDerm™ conformed to those of in vivo MN assay, whereas those of NHEKs did not. The effect of cell differentiation status on MN induction was further addressed using a model compound, epigallocatechin gallate (EGCG), which is a major component of green tea extract that shows positive results in in vitro mammalian genotoxicity assays via oxidative stress and negative results in in vivo MN studies. RSMN assay in an underdeveloped epidermal model, EpiDerm-201™ (MatTek Corporation), showed a negative result identical to that in EpiDerm™, indicating that the barrier function of keratinocytes has limited impact. Analysis of the gene expression profile of both EpiDerm™ and NHEKs after EGCG treatment for 12h revealed that the expression of genes related to genotoxic response was significantly induced only in NHEKs. Conversely, antioxidative enzyme activities (catalase and glutathione peroxidase) in EpiDerm™ were higher than those in NHEKs. These results indicate that EpiDerm™ has antioxidant properties similar to those of a living body and is capable of eliminating oxidative stress that may be caused by EGCG under in vitro experimental conditions. PMID:23988588

  2. In vivo photochemical skin micronucleus test using a sunlight simulator: detection of 8-methoxypsoralen and benzo[a]pyrene in hairless mice.

    PubMed

    Hara, Takumi; Nishikawa, Takashi; Sui, Hajime; Kawakami, Kumiko; Matsumoto, Hirotaka; Tanaka, Noriho

    2007-07-10

    Evaluating in vivo photochemical genotoxicity (photogenotoxicity) or photochemical carcinogenicity (photocarcinogenicity) in the skin that is actually exposed to light is important for estimating the risk of human exposure to chemicals under sunlight. With regard to the skin micronucleus test, Nishikawa et al. developed a reliable technique that is simple and in which the negative control has a stable background. In the present study, we applied 8-methoxypsoralen (8-MOP) and benzo[a]pyrene (B[a]P) to the backs of hairless mice and subjected the mice to irradiation by a sunlight simulator in order to investigate whether this test can detect photogenotoxicity of these chemicals. In the treatment with 8-MOP [0.00075% and 0.0015% (w/v)], a significant increase was observed in the frequency of micronucleated cells only under light irradiation using the sunlight simulator. At a high chemical dose, the frequency of micronucleated cells increased from 48h after the treatment, peaked at 96h, and then decreased at 168h. Furthermore, at 96h with the high dose under light irradiation, we frequently observed cells with nuclear buds. In the treatment with B[a]P [first experiment: 0.025% and 0.05% (w/v); second experiment: 0.005%, 0.01%, and 0.02% (w/v)], a significant increase was observed in the frequency of micronucleated cells at skin-irritating doses [0.01%, 0.02%, 0.025%, and 0.05% (w/v)] at 72 or 96h after the treatment only under light irradiation using the sunlight simulator. In conclusion, photogenotoxicity of 8-MOP and B[a]P was detected in the in vivo photochemical skin micronucleus study. PMID:17512241

  3. 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

  4. Effect of p53 Arg72Pro polymorphism on the induction of micronucleus by aflatoxin B1 in in vitro in human blood lymphocytes.

    PubMed

    Bayram, Süleyman; Rencüzoğulları, Eyyüp; Almas, Abdullah Muttalip; Genç, Ahmet

    2016-07-01

    Aflatoxin B1 (AFB1) is a class 1 carcinogen produced by Aspergillus flavus and Aspergillus parasiticus that can contaminate a variety of food substances, the liver being its target organ. A common p53 Arg72Pro polymorphism resulting in the substitution of an arginine amino acid by proline amino acid in the transactivating domain has been demonstrated to affect p53 function. The aim of this study is to investigate association between p53 Arg72Pro polymorphism and the frequencies of spontaneous and AFB1-induced DNA damage in peripheral blood lymphocytes from 100 healthy individuals in Turkish population. In vitro cytokinesis-blocked micronucleus (CBMN) assay was used to detect the spontaneous and AFB1-induced DNA damage whereas, genotyping of p53 Arg72Pro polymorphism was carried out by using a polymerase chain reaction restriction fragment length polymorphism assay. During 68 h incubation time, lymphocytes treated with AFB1 (1.56 μg/mL) and S9 mix for a total of 3 h (48-51 h). Treatment of the lymphocytes with AFB1significantly increased the overall frequencies of micronucleus (MN) when compared to untreated cultures (1.23 ± 0.05 versus 0.55 ± 0.02; p < 0.001). Moreover, genotype analysis revealed a statistically significant association between Pro/Pro genotype of p53 Arg72Pro polymorphism and increased frequencies of MN both spontaneous and AFB1-induced cultures when compared Arg/Arg genotype (0.69 ± 0.19 versus 0.46 ± 0.13, p < 0.001; 1.59 ± 0.65 versus 1.01 ± 0.41 p < 0.001; respectively). Our data indicate that p53 Arg72Pro polymorphism plays a significant role in human sensitivity to the genotoxic effects of AFB1. Further investigations in larger sample size and with different ethnic origins as well as including more functional single nucleotide polymorphisms might lead to the identification of novel genetic factors responsible for susceptibility to human carcinogens such as AFB1. PMID:26738694

  5. 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. PMID:25892619

  6. In vitro study of mutagenic potential of Bidens pilosa Linné and Mikania glomerata Sprengel using the comet and micronucleus assays.

    PubMed

    Costa, Ronaldo de Jesus; Diniz, Andréa; Mantovani, Mário Sérgio; Jordão, Berenice Quinzani

    2008-06-19

    Teas of Bidens pilosa and Mikania glomerata are popularly consumed to medicinal ends. The capacity to induce DNA damages and mutagenic effects of these teas were evaluated, in vitro, on HTC cells, with comet assay and micronucleus test. The teas tested at various doses were prepared differently: infusion of Mikania glomerata (IM) and Bidens pilosa (IB), macerate of Mikania glomerata in 80% ethanol (MM80) and decoction of Bidens pilosa (DB). In IM and MM80, the quantity of coumarin was determined by high-performance liquid chromatography (HPLC) with UV detection. Methylmethanesulfonate was utilized as positive control, phosphate-buffered saline as negative control, 80% ethanol as solvent control and 2-aminoanthracene as drug metabolism control. The comet assay demonstrated genotoxic effects for both plants. The genotoxic potential of IB was upper than DB, showing dose-response. In the MN test, excepting IM 40 microL/mL, all treatments was not mutagenic. The effects did not show direct relation with cumarin quantity present in IM and MM80. The results demonstrated DNA damages at the highest concentrations of alcoholic macerate (10 and 20 microL/mL) and infusion of Mikania glomerata (20 and 40 microL/mL) and of Bidens pilosa infusion (40 microL/mL). Thus, both dose and preparation-form suggest caution in the phytotherapeutic use of these plants. PMID:18485638

  7. 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. PMID:24361376

  8. 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

  9. 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. PMID:24277431

  10. Monitoring genotoxicity among gasoline station attendants and traffic enforcers in the City of Manila using the micronucleus assay with exfoliated epithelial cells.

    PubMed

    Hallare, A V; Gervasio, M K R; Gervasio, P L G; Acacio-Claro, P J B

    2009-09-01

    Some types of occupations involve high levels of exposure to potentially genotoxic gaseous and particulate substances from internal combustion engines used in motor vehicles. These occupational exposures may contribute to the development of many illnesses, usually through chromosomal change mechanisms that include strand breakage, deletions, sister chromatid exchange and non-disjunction. To determine the effect of occupational exposure in gasoline station attendants and traffic enforcers, the micronucleus test was used. Exfoliated oral mucosa cells from 18 gasoline station attendants, 18 traffic enforcers and 18 control subjects in the City of Manila were examined for micronucleated cell (MNC) frequency. Analysis of buccal cells showed that MNC frequencies in exposed individuals were significantly greater than in control subjects (p < or = 0.05). However, between gasoline station attendants and traffic enforcers, MNC frequencies of the two exposed groups exhibited no significant difference. No relation was also found between MNC frequency and any of the factors such as age, smoking habits, alcohol habits and working period. This was further confirmed in the multiple regression analysis which showed that only occupational exposure was a good predictor of MNC frequency. The results of this study suggest that gasoline station attendants and traffic enforcers, compared to the control individuals, are at a greater risk of chromosomal damage. For the assessment of chromosomal damage, the study, development, and standardization of tests are recommended for public institutions concerned with matters regarding environmental quality and community health. PMID:18712612

  11. Evaluation of DNA damage induced by decabromodiphenyl ether (BDE-209) in hemocytes of Dreissena polymorpha using the comet and micronucleus assays.

    PubMed

    Riva, Consuelo; Binelli, Andrea; Cogni, Daniele; Provini, Alfredo

    2007-12-01

    The recent widespread production and use of flame retardants, polybrominated diphenyl ethers (PBDEs), is one of the reason of the increasing contamination observed worldwide. At the present, deca-BDE mixture, in which the decabromodiphenyl ether (BDE-209) is the major congener (98%), dominates the EU market. The potential genotoxicity of BDE-209 was examined in the freshwater bivalve zebra mussel (Dreissena polymorpha) by means of Comet assay and micronucleus assay (MN assay). Mussels were exposed in vivo to BDE-209 at nominal concentration of 0.1, 2, and 10 mug/l under laboratory conditions. The assays were performed on the bivalve hemocytes monitoring the levels of DNA strand breaks and the percentage of micronuclei until 168 and 96 hr of exposure, respectively. At the same time, BDE-209 levels were measured daily in mussel soft tissues to evaluate the bioaccumulation. Results of the Comet assay showed a significant increase of DNA damages compared to controls, but a lack of dose/effect relationship probably due to the formation of less-brominated congeners. By contrast, no significant changes in MN frequency from baseline levels were observed. These preliminary results about the potential genotoxicity of this compound in invertebrates indicated a clear BDE-209 capability to induce DNA damage, but no irreversible effects on DNA hemocytes. Furthermore, bioaccumulation of this high-molecular-weight substance and its uptake mechanism in zebra mussel are also discussed. PMID:17973311

  12. Evaluation of repeated dose micronucleus assays of the liver and gastrointestinal tract using potassium bromate: a report of the collaborative study by CSGMT/JEMS.MMS.

    PubMed

    Okada, Emiko; Fujiishi, Yohei; Narumi, Kazunori; Kado, Shoichi; Wako, Yumi; Kawasako, Kazufumi; Kaneko, Kimiyuki; Ohyama, Wakako

    2015-03-01

    The food additive potassium bromate (KBrO3) is known as a renal carcinogen and causes chromosomal aberrations in vitro without metabolic activation and in vivo in hematopoietic and renal cells. As a part of a collaborative study by the Mammalian Mutagenicity Study group, which is a subgroup of the Japanese Environmental Mutagen Society, we administered KBrO3 to rats orally for 4, 14, and 28 days and examined the micronucleated (MNed) cell frequency in the liver, glandular stomach, colon, and bone marrow to confirm whether the genotoxic carcinogen targeting other than liver and gastrointestinal (GI) tract was detected by the repeated dose liver and GI tract micronucleus (MN) assays. In our study, animals treated with KBrO3 showed some signs of toxicity in the kidney and/or stomach. KBrO3 did not increase the frequency of MNed cells in the liver and colon in any of the repeated dose studies. However, KBrO3 increased the frequency of MNed cells in the glandular stomach and bone marrow. Additionally, the MNed cell frequency in the glandular stomach was not significantly affected by the difference in the length of the administration period. These results suggest that performing the MN assay using the glandular stomach, which is the first tissue to contact agents after oral ingestion, is useful for evaluating the genotoxic potential of chemicals and that the glandular stomach MN assay could be integrated into general toxicity studies. PMID:24637080

  13. Radiation-induced micronucleus induction in lymphocytes identifies a high frequency of radiosensitive cases among breast cancer patients: a test for predisposition?

    PubMed Central

    Scott, D.; Barber, J. B.; Levine, E. L.; Burrill, W.; Roberts, S. A.

    1998-01-01

    Enhanced sensitivity to the chromosome-damaging effects of ionizing radiation is a feature of many cancer-predisposing conditions. We previously showed that 42% of an unselected series of breast cancer patients and 9% of healthy control subjects showed elevated chromosomal radiosensitivity of lymphocytes irradiated in the G2 phase of the cell cycle. We suggested that, in addition to the highly penetrant genes BRCA1 and BRCA2, which confer a very high risk of breast cancer and are carried by about 5% of all breast cancer patients, there are also low-penetrance predisposing genes carried by a much higher proportion of breast cancer patients, a view supported by recent epidemiological studies. Ideally, testing for the presence of these putative genes should involve the use of simpler methods than the G2 assay, which requires metaphase analysis of chromosome damage. Here we report on the use of a simple, rapid micronucleus assay in G0 lymphocytes exposed to high dose rate (HDR) or low dose rate gamma-irradiation, with delayed mitogenic stimulation. Good assay reproducibility was obtained, particularly with the HDR protocol, which identified 31% (12 out of 39) of breast cancer patients compared with 5% (2 out of 42) of healthy controls as having elevated radiation sensitivity. In the long term, such cytogenetic assays may have the potential for selecting women for intensive screening for breast cancer. PMID:9484819

  14. Genotoxicity assessment of NIM-76 and its formulation (pessary) in an in vitro Ames Salmonella/microsome assay and in vivo mouse bone marrow micronucleus test.

    PubMed

    Vijayan, Vinod; Meshram, Ghansham P

    2013-10-01

    The possible genotoxic potential of NIM-76, a volatile fraction obtained from neem oil, having promising contraceptive activity, as well as its formulation product, called pessary (7.5% NIM-76 in polyethylene glycol), were evaluated in the Ames assay and mouse bone marrow micronucleus (MN) assay. Genotoxicity of NIM-76 (0.1-1000 µg/plate) and pessary (0.1-10,000 µg/plate) were studied using the liquid preincubation protocol of the Ames assay both in the presence and absence of S9. Likewise, the ability of NIM-76 [1-1000 mg/kg body weight (b.w.)] and its formulation product (18.75-300 mg/kg b.w.) to induce clastogenic effects were studied in the female mouse bone marrow MN test by using a two-dose intraperitoneal treatment protocol. There was no increase in the number of revertant colonies resulting from NIM-76 or pessary at any of their doses over the respective negative control plates, either in the presence or absence of S9. Similarly, in the MN assay, neither of them showed any clastogenic activity because there was no significant increase in the frequency of micronucleated polychromatic erythrocytes, over the negative control group of animals. The use of this compound in humans is therefore not likely to have mutagenic effects and may be considered as safe with regard to genotoxic potential. PMID:23527474

  15. Reducing Dropouts.

    ERIC Educational Resources Information Center

    Timpane, Michael; And Others

    A group of three conference papers, all addressing the subject of effective programs to decrease the number of school dropouts, is presented in this document. The first paper, "Systemic Approaches to Reducing Dropouts" (Michael Timpane), asserts that dropping out is a symptom of failures in the social, economic, and educational systems. Dropping…

  16. Effects of genetic polymorphisms of metabolic enzymes on cytokinesis-block micronucleus in peripheral blood lymphocyte among coke-oven workers

    SciTech Connect

    Shuguang Leng; Yufei Dai; Yong Niu; Zufei Pan; Xiaohua Li; Juan Cheng; Fengsheng He; Yuxin Zheng

    2004-10-15

    Exploring the associations between genetic polymorphisms of metabolic enzymes and susceptibility to polycyclic aromatic hydrocarbon (PAH)-induced chromosomal damage is of great significance for understanding PAH carcinogenesis. Cytochrome P450, glutathione S-transferase, microsomal epoxide hydrolase, NAD(P)H:quinone oxidoreductase, and N-acetyltransferase are PAH-metabolizing enzymes. In this study, we genotyped for the polymorphisms of these genes and assessed their effects on cytokinesis-block micronucleus (CBMN) frequencies in peripheral blood lymphocytes among 141 coke-oven workers and 66 non-coke-oven worker controls. The geometric means of urinary 1-hydroxypyrene levels in coke-oven workers and the controls were 12.0 and 0.7 {mu}mol/mol creatinine, respectively. The CBMN frequency (number of micronuclei per 1,000 binucleated lymphocytes) was significantly higher in coke-oven workers (9.5 {+-} 6.6) than in the controls. Among the coke-oven workers, age was positively associated with CBMN frequency; the mEH His{sup 113} variant genotype exhibited significantly lower CBMN frequency than did the Tyr{sup 113}/Tyr{sup 113} genotype; the low mEH activity phenotype exhibited a lower CBMN frequency than did the high mEH activity phenotype; the GSTP1 Val{sup 105}/Val{sup 105} genotype exhibited a higher CBMN frequency than did the GSTP1 Ile{sup 105}/Ile{sup 105} or Ile{sup 105}/Val{sup 105} genotypes; the joint effect of high mEH activity phenotype and GSTM1 null genotype on CBMN frequencies was also found. Gene-environment interactions between occupational PAH exposure and polymorphisms of mEH and/or GSTM1 were also evident. These results indicate that the mEH, GSTP1, and GSTM1 polymorphisms may play a role in sensitivity or genetic susceptibility to the genotoxic effects of PAH exposure in the coke-oven workers.

  17. 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. PMID:25053835

  18. 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.

  19. International amphibian micronucleus standardized procedure (ISO 21427-1) for in vivo evaluation of double-walled carbon nanotubes toxicity and genotoxicity in water.

    PubMed

    Mouchet, Florence; Landois, Perine; Datsyuk, Vitaliy; Puech, Pascal; Pinelli, Eric; Flahaut, Emmanuel; Gauthier, Laury

    2011-04-01

    Considering the important production of carbon nanotubes (CNTs), it is likely that some of them will contaminate the environment during each step of their life cycle. Nevertheless, there is little known about their potential ecotoxicity. Consequently, the impact of CNTs on the environment must be taken into consideration. This work evaluates the potential impact of well characterized double-walled carbon nanotubes (DWNTs) in the amphibian larvae Xenopus laevis under normalized laboratory conditions according to the International Standard micronucleus assay ISO 21427-1:2006 for 12 days of half-static exposure to 0.1-1-10 and 50 mg L(-1) of DWNTs in water. Two different endpoints were carried out: (i) toxicity (mortality and growth of larvae) and (ii) genotoxicity (induction of micronucleated erythrocytes). Moreover, intestine of larvae were analyzed using Raman spectroscopy. The DWNTs synthetized by catalytic chemical vapor deposition (CCVD) were used as produce (experiment I) and the addition of Gum Arabic (GA) was investigated to improve the stability of the aqueous suspensions (experiment II). The results show growth inhibition in larvae exposed to 10 and 50 mg L(-1) of DWNTs with or without GA. No genotoxicity was evidenced in erythrocytes of larvae exposed to DWNTs, except to 1 mg L(-1) of DWNTs with GA suggesting its potential effect in association with DWNTs at the first nonacutely toxic concentration. The Raman analysis confirmed the presence of DWNTs into the lumen of intestine but not in intestinal tissues and cells, nor in the circulating blood of exposed larvae. PMID:20014232

  20. Genotoxicity evaluation of Guibi-Tang extract using an in vitro bacterial reverse mutation assay, chromosome aberration assay, and in vivo micronucleus test

    PubMed Central

    2014-01-01

    Background Guibi-Tang is a traditional herbal prescription made from 12 different herbs that is used in the treatment of amnesia and poor memory. Methods In the present study, we evaluated the acute oral toxicity and genotoxic potential of Guibi-Tang water extract (GBT) at doses up to 2000 μg/plate an using a bacterial reverse mutation test (Ames test) with Salmonella typhimurium strains TA100, TA1535, TA98, and TA1537, and Escherichia coli strain WP2uvrA. Acute toxicity and genotoxic potential were measured in the presence and absence of an exogenous source of metabolic activation, in an in vitro chromosome aberration assay with Chinese hamster lung (CHL) cells, and in an in vivo micronucleus test using ICR mice bone marrow as recommended by the Korean Food and Drug Administration. An acute oral toxicity test of GBT was performed in Sprague Dawley rats. The Ames test showed that GBT did not induce gene mutations in S. typhimurium or in E. coli in the presence or absence of S9 activation. Results GBT did not significantly increase the number of structural aberrations in CHL cells with or without S9 activation. The oral administration of GBT at a dose of up to 2000 mg/kg caused no significant increase in the number of micronucleated polychromatic erythrocytes or in the mean ratio of polychromatic to total erythrocytes. Conclusions However, as we did not identify the components of GBT responsible for these effects, other assays are needed to confirm its genotoxicity. PMID:24985139

  1. 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. PMID:27169373

  2. Evaluation of the genotoxicity of 10 selected dietary/environmental compounds with the in vitro micronucleus cytokinesis-block assay in an interlaboratory comparison.

    PubMed

    Katic, Jelena; Cemeli, Eduardo; Baumgartner, Adolf; Laubenthal, Julian; Bassano, Irene; Stølevik, Solvor B; Granum, Berit; Namork, Ellen; Nygaard, Unni C; Løvik, Martinus; van Leeuwen, Danitsja; Vande Loock, Kim; Anderson, Diana; Fucić, Aleksandra; Decordier, Ilse

    2010-10-01

    Complex exposure to xenobiotics is one of the reasons for the reported increase of respiratory diseases, cancer and immunological disturbances. Among such xenobiotics there are food mutagens whose effects on human health in the low level and/or chronic exposure still remains unknown. In the present manuscript, the compounds ethanol (EtOH), 4-hydroxynonenal (4-HNE), malondialdehyde (MDA), 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), 3,3',4,4'-tetrachlorobiphenyl (PCB 153), benzo[a]pyrene (BaP), 2-amino-3-methylimidazol[4,5-f]quinoline (IQ), 2-amino-1-methyl-6-phenylimidazol[4,5-b]pyridine (PhIP), N-Nitrosodimethylamine (NDMA) and acrylamide (AA) were evaluated in an interlaboratory comparison in the in vitro cytokinesis-block micronucleus assay (CBMN) with objective of assessing the induction of micronuclei, buds and nucleoplasmic bridges in dose responses. Statistically significant increase in MNBN frequency in binucleated cells was recorded by both laboratories for the compound PhIP (2.5μM). The compounds PCB (250 microM) and AA (500 microM) induced statistically significant increase of MNBN although it was recorded by one of the two laboratories. Induction of buds and nucleoplasmic bridges was only observed for BaP (100 microM) and AA (500 microM) by one of the laboratories. Data generated in this study may assist in the interpretation of the mother/newborn biomonitoring study being carried out within project NewGeneris and will contribute to overall knowledge on the genotoxic potential of dietary/environmental toxicants. PMID:20600534

  3. 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. PMID:25986082

  4. 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. PMID:24478133

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

    PubMed

    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 50mg/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. PMID:26232259

  6. A comparative biomonitoring study of populations residing in regions with low and high risk of lung cancer using the chromosome aberration and the micronucleus tests.

    PubMed

    Heepchantree, Worapa; Paratasilpin, Thipmani; Kangwanpong, Daoroong

    2005-11-10

    Chromosome aberration (CA) and micronucleus (MN) tests were performed in peripheral blood lymphocytes from people residing in two districts of Chiang Mai, Thailand, a high-risk area, Saraphi (n=107), where the lung cancer incidence is three-fold higher than in a low-risk area, Chom Thong (n=118). The percentage of cells with CAs was significantly lower in the Saraphi population than in the Chom Thong population (0.47+/-0.91 versus 1.04+/-1.18, P=0.0001) as was the percentage of CAs (0.49+/-0.91 versus 1.08+/-1.21, P<0.0001) and the mitotic indices (1.25+/-0.44 versus 1.33+/-0.33, P=0.025). The frequency of MN in binucleated (BN) cells, however, was significantly higher in the Saraphi population (12.01+/-3.57 versus 9.99+/-3.11, P<0.0001) as was the percentage of BN cells with MN (1.14+/-0.31 versus 0.93+/-0.23, P<0.0001). There was no difference in the nuclear division indices (1.49+/-0.07 versus 1.47+/-0.11, P=0.1759) between the two populations. With regard to the effect of confounding factors, it was found that cigarette smoking influenced both CA and MN frequencies, and that the chewing of fermented tea leaves or betel nuts affected CA and sex affected MN frequencies. An increasing of CA and MN frequencies were seen in smokers and chewers over non-smokers and non-chewers, with CA frequencies being higher in Chom Thong smokers and chewers and MN frequency being higher in Saraphi smokers. However, pesticide exposure and alcohol consumption had no impact on CA and MN frequencies. Due to the conflicting results obtained in the two tests, we cannot make a clear statement regarding the potential effects of the environmental exposures in the two study populations. PMID:16185913

  7. Use of the Cytokinesis-Blocked Micronucleus Assay (CBMN) to Detect Gender Differences and Genetic Instability in a Lung Cancer Case-Control Study

    PubMed Central

    McHugh, Michelle K.; Lopez, Mirtha S.; Ho, Chung-Han; Spitz, Margaret R.; Etzel, Carol J.; El-Zein, Randa A.

    2012-01-01

    Background Although tobacco exposure is the predominant risk factor for lung cancer, other environmental agents are established lung carcinogens. Measuring the genotoxic effect of environmental exposures remains equivocal as increases in morbidity and mortality may be attributed to co-exposures such as smoking. Methods We evaluated genetic instability and risk of lung cancer associated with exposure to environmental agents (e.g., exhaust) and smoking among 500 lung cancer cases and 500 controls using the Cytokinesis-Blocked Micronucleus (CBMN) assay. Linear regression was applied to estimate the adjusted means of the CBMN endpoints (micronuclei and nucleoplasmic bridges). Logistic regression analyses were used to estimate lung cancer risk and to control for potential confounding by age, gender, and smoking. Results Cases showed significantly higher levels of micronuclei and nucleoplasmic bridges as compared to controls (mean ± SEM=3.54±0.04 vs.1.81 ±0.04 and mean ± SEM=4.26±0.03 vs. 0.99±0.03, respectively; p <0.001) with no differences among participants with or without reported environmental exposure. No differences were observed when stratified by smoking or environmental exposure among cases or controls. A difference in lung cancer risk was observed between non-exposed male and female heavy smokers, although it was not statistically significant (I2=64.9%; P-value for Q statistic=0.09). Conclusions Our study confirms that the CBMN assay is an accurate predictor of lung cancer and supports the premise that heavy smoking may have an effect on DNA repair capacity and in turn modulate the risk of lung cancer. Impact Identifying factors that increase lung cancer risk may lead to more effective prevention measures. PMID:23195992

  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) PMID:2582927

  10. A four-day oral treatment regimen for simultaneous micronucleus analyses in the glandular stomach, colon, and bone marrow of rats.

    PubMed

    Okada, Emiko; Fujiishi, Yohei; Narumi, Kazunori; Yasutake, Nobuyoshi; Ohyama, Wakako

    2013-12-12

    Our aim was to develop a multi-tissue micronucleus (MN) test method for the simultaneous analysis of rat glandular stomach, colon, and bone marrow. We have evaluated the multi-tissue MN test method with a regimen in which rats were administered chemicals orally once per day for four days and the cells of each tissue were collected 24 h after the final dose. The following compounds were studied: N-nitroso-N-methylurea (MNU), 4-nitroquinoline-1-oxide (4NQO), N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), N-methyl-N-nitrosourethane (NMUT), 1,2-dimethylhydrazine 2HCl (DMH), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine HCl (PhIP), KBrO(3), amaranth (AM), and quercetin (QN). The gastrointestinal tract carcinogens increased the frequencies of micronucleated (MNed) cells in target tissue in a dose-dependent manner: MNU in gastric- and colonic-cells; 4NQO, MNNG, and NMUT in gastric cells; DMH and PhIP in colonic cells. In immature erythrocytes, MNU, 4NQO, DMH, and PhIP increased the frequency of MNed cells but MNNG and NMUT did not. The food additive KBrO(3), which is known to be a renal carcinogen, increased the frequencies of MNed cells in the glandular stomach and bone marrow. The food additive AM and the plant flavonoid QN, which are non-carcinogenic in most studies, did not cause increased MNed cells in any of the three tissues. Our results indicate that this multi-tissue MN test method is useful for the comprehensive evaluation of the genotoxicity of orally administered compounds. PMID:24140632

  11. 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

  12. Evaluation of the genotoxicity and cytotoxicity in the buccal epithelial cells of patients undergoing orthodontic treatment with three light-cured bonding composites by using micronucleus testing

    PubMed Central

    Yuksel, Sengul; Ozturk, Firat; Karatas, Orhan Hakki; Yalcin, Muhammet

    2014-01-01

    Objective This study evaluated the cytotoxicity and genotoxicity of fixed orthodontic treatment with three different light-cured orthodontic bonding composites by analyzing micronucleus (MN) formation in the buccal mucosa during a 6-month period. Methods Thirty healthy volunteers were selected from consecutive patients referred for orthodontic treatment. Equilibrium 2 brackets and molar tubes (Dentaurum) were bonded with three different light-cured orthodontic bonding composites-Transbond XT (3M Unitek), Kurasper F (Kuraray Europe), or GrenGloo (Ormco Corporation)- to all teeth in both arches. Exfoliated buccal epithelial cells were scraped from the middle part of the inner cheeks with sterile cement spatulas before treatment and at 1, 3, and 6 months after treatment. MNs and nuclear alterations, such as karyorrhexis (KR), karyolysis (KL), and binucleated cells (BNs), were scored under a light microscope. Repeated measure ANOVA was used to calculate statistical differences in degenerative nuclear abnormalities. Results MN rates did not significantly differ among different time points within the same cell type (p > 0.05). In contrast, the number of BNs in buccal epithelial cells significantly increased in all composite groups (p < 0.01, Transbond XT; p < 0.001, Kurasper F and GrenGloo). KL frequency significantly increased between the beginning and end of the study in the Kurasfer F (0.80 ± 0.79 to 1.90 ± 1.10; p < 0.05) and GrenGloo (1.30 ± 1.06 to 2.40 ± 1.08; p < 0.05) groups. Conclusions After 6 months of fixed orthodontic treatment with different light-cured composites, morphological signs of cytotoxicity were observed but genotoxic effects were absent. PMID:24892026

  13. 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. PMID:27562929

  14. Unfermented grape juice reduce genomic damage on patients undergoing hemodialysis.

    PubMed

    Corredor, Zuray; Rodríguez-Ribera, Lara; Coll, Elisabeth; Montañés, Rosario; Diaz, Juan Manuel; Ballarin, José; Marcos, Ricard; Pastor, Susana

    2016-06-01

    Chronic kidney disease (CKD) patients in dialysis (HD) are considered to be submitted to a continuous oxidative stress. This stress can cause damage on DNA and, consequently, contribute to the high levels of DNA damage observed in these patients. Due to the well-known role of polyphenols as antioxidant agents we proposed its use to reduce the levels of genotoxicity present in HD-CKD patients. The objective of this study was to evaluate the antigenotoxic effects of unfermented grape juice (UGJ) on HD-CKD patients. The levels of DNA damage were analyzed using different biomarkers, such as breaks and oxidized DNA bases by the comet assay, chromosome damage by the micronucleus test. In addition, TEAC (Trolox equivalent antioxidant capacity) was also evaluated. Thirty-nine patients were followed for six months, of whom 25 were supplemented by UGJ and 14 were not supplemented. The obtained results showed a significant decrease in the underlying levels of oxidative DNA damage, in the supplemented group. Regarding the clinical parameters, LDL and cholesterol, were significantly reduced in the patients studied after the supplementation period, although cholesterol was also decreased in the non-supplemented patients. In conclusion, in our studied group the supplementation with UGJ reduced the levels of oxidative DNA damage of HD-CKD patients. PMID:27016493

  15. 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. PMID:26410583

  16. 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

  17. 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

  18. The application of the cytokinesis-block micronucleus assay on peripheral blood lymphocytes for the assessment of genome damage in long-term residents of areas with high radon concentration

    PubMed Central

    Sinitsky, Maxim Yu.; Druzhinin, Vladimir G.

    2014-01-01

    Estimating the effects of small doses of ionising radiation on DNA is one of the most important problems in modern biology. Different cytogenetic methods exist to analyse DNA damage; the cytokinesis-block micronucleus assay (CBMN) for human peripheral blood lymphocytes is a simple, cheap and informative cytogenetic method that can be used to detect genotoxic-related markers. With respect to previous studies on radiation-induced genotoxicity, children are a poorly studied group, as evidenced by the few publications in this area. In this study, we assessed radon genotoxic effects by counting micronuclei (MN), nucleoplasmic bridges (NPBs) and nuclear buds (NBUDs) in the lymphocytes of children who are long-term residents from areas with high radon concentrations. In the exposed group, radon was found to cause significant cytogenetic alterations. We propose that this method can be employed for biomonitoring to screen for a variety of measures. PMID:23908554

  19. 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. PMID:26813850

  20. Genotoxic effects of p,p'-DDT (1,1,1-trichloro-2,2-bis-(chlorophenyl)ethane) and its metabolites in Zebra mussel (D. polymorpha) by SCGE assay and micronucleus test.

    PubMed

    Binelli, Andrea; Riva, Consuelo; Cogni, Daniele; Provini, Alfredo

    2008-06-01

    This is the first study to evaluate the potential genotoxicity of p,p'-DDT (1,1,1-trichloro-2,2-bis-(chlorophenyl)ethane) and its metabolites (p,p'-DDD and p,p'-DDE) in the sentinel mollusc Zebra mussel (Dreissena polymorpha). DNA damage was measured using the single cell gel electrophoresis (SCGE) assay and the micronucleus test (MN test), which represent two of the more sensitive biomarkers for genotoxicity evaluation. Three different concentrations (0.1, 2, and 10 mug/L) of each compound were administered in water for 168 hr, maintaining mussels at constant laboratory conditions and collecting several specimens every 48 hr for biochemical analyses. At the same time, the bioaccumulation process and the concentration/effect relationship were checked by GC-MS/MS analyses of mussel soft tissues. The SCGE assay results showed a clear and significant (P < 0.05) relationship between DNA injuries and tested doses for all the homologues throughout the 7-day exposure period. The final DNA damage due to p,p'-DDE was almost double that of the other two homologues that showed the same toxicity pattern. The micronucleus frequency analysis confirmed the genotoxicity potential of the three homologues and p,p'-DDE showed the highest irreversible DNA damage. The capability of Zebra mussels to biotransform the administered compound in the other homologues was demonstrated by multiple regression analyses carried out between the MN frequencies and the concentrations of the different homologues in the mussel soft tissues. A greater genotoxic potential of the p,p'-DDE with respect to the other two chemicals was revealed. PMID:18418866

  1. 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 Central

    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. PMID:23936030

  2. 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

  3. 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). PMID:27160659

  4. Biomonitoring of the genotoxic potential of aqueous extracts of soils and bottom ash resulting from municipal solid waste incineration, using the comet and micronucleus tests on amphibian (Xenopus laevis) larvae and bacterial assays (Mutatox and Ames tests).

    PubMed

    Mouchet, F; Gauthier, L; Mailhes, C; Jourdain, M J; Ferrier, V; Triffault, G; Devaux, A

    2006-02-15

    The management of contaminated soils and wastes is a matter of considerable human concern. The present study evaluates the genotoxic potential of aqueous extracts of two soils (leachates) and of bottom ash resulting from municipal solid waste incineration (MSWIBA percolate), using amphibian larvae (Xenopus laevis). Soil A was contaminated by residues of solvents and metals and Soil B by polycyclic aromatic hydrocarbons and metals. MSWIBA was predominantly contaminated by metals. Two genotoxic endpoints were analysed in circulating erythrocytes taken from larvae: clastogenic and/or aneugenic effects (micronucleus induction) after 12 days of exposure and DNA-strand-breaking potency (comet assay) after 1 and 12 days of exposure. In addition, in vitro bacterial assays (Mutatox and Ames tests) were carried out and the results were compared with those of the amphibian test. Physicochemical analyses were also taken into account. Results obtained with the amphibians established the genotoxicity of the aqueous extracts and the comet assay revealed that they were genotoxic from the first day of exposure. The latter test could thus be considered as a genotoxicity-screening tool. Although genotoxicity persisted after 12 days' exposure, DNA damage decreased overall between days 1 and 12 in the MSWIBA percolate, in contrast to the soil leachates. Bacterial tests detected genotoxicity only for the leachate of soil A (Mutatox). The results confirm the ecotoxicological relevance of the amphibian model and underscore the importance of bioassays, as a complement to physico-chemical data, for risk evaluation. PMID:16442436

  5. 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. PMID:26190540

  6. 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 ...

  7. 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

  8. 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. PMID

  9. Vanadium Nitrogenase Reduces CO*

    PubMed Central

    Lee, Chi Chung; Hu, Yilin; Ribbe, Markus W.

    2011-01-01

    Vanadium nitrogenase not only reduces dinitrogen to ammonia but also reduces carbon monoxide to ethylene, ethane, and propane. The parallelism between the two reactions suggests a potential link in mechanism and evolution between the carbon and nitrogen cycles on Earth. PMID:20689010

  10. Vanadium nitrogenase reduces CO.

    PubMed

    Lee, Chi Chung; Hu, Yilin; Ribbe, Markus W

    2010-08-01

    Vanadium nitrogenase not only reduces dinitrogen to ammonia but also reduces carbon monoxide to ethylene, ethane, and propane. The parallelism between the two reactions suggests a potential link in mechanism and evolution between the carbon and nitrogen cycles on Earth. PMID:20689010

  11. 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.

  12. 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…

  13. Reducing Childhood Obesity

    MedlinePlus

    ... Bar Home Current Issue Past Issues Reducing Childhood Obesity Past Issues / Summer 2007 Table of Contents For ... Ga. were the first three We Can! cities. Obesity Research: A New Approach The percentage of children ...

  14. Reduced Extended MHD

    NASA Astrophysics Data System (ADS)

    Morrison, P. J.; Abdelhamid, H. M.; Grasso, D.; Hazeltine, R. D.; Lingam, M.; Tassi, E.

    2015-11-01

    Over the years various reduced fluid models have been obtained for modeling plasmas, with the goal of capturing important physics while maintaining computability. Such models have included the physics contained in various generalizations of Ohm's law, including Hall drift and electron inertia. In a recent publication it was shown that full 3D extended MHD is a Hamiltonian system by finding its noncanonical Poisson bracket. Subsequently, this bracket was shown to be derivable from that for Hall MHD by a series of remarkable transformations, which greatly simplifies the proof of the Jacobi identity and allows one to immediately obtain generalizations of the helicity and cross helicity. In this poster we use this structure to obtain exact reduced fluid models with the effects of full two-fluid theory. Results of numerical computations of collisionless reconnection using an exact reduced 4-field model will be presented and analytical comparisons of mode structure of previous reduced models will be made.

  15. Reducing Teacher Stress.

    ERIC Educational Resources Information Center

    Docking, R. A.; Docking, E.

    1984-01-01

    Reports on a case study of inservice training conducted to enhance the teacher/student relationship and reduce teacher anxiety. Found significant improvements in attitudes, classroom management activities, and lower anxiety among teachers. (MD)

  16. REDUCED PROTECTIVE CLOTHING DETERMINATIONS

    SciTech Connect

    BROWN, R.L.

    2003-06-13

    This technical basis document defines conditions where reduced protective clothing can be allowed, defines reduced protective clothing, and documents the regulatory review that determines the process is compliant with the Tank Farm Radiological Control Manual (TFRCM) and Title 10, Part 835, of the Code of Federal Regulations (10CFR835). The criteria, standards, and requirements contained in this document apply only to Tank Farm Contractor (TFC) facilities.

  17. 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.

  18. 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.

  19. Reduced Vector Preisach Model

    NASA Technical Reports Server (NTRS)

    Patel, Umesh D.; Torre, Edward Della; Day, John H. (Technical Monitor)

    2002-01-01

    A new vector Preisach model, called the Reduced Vector Preisach model (RVPM), was developed for fast computations. This model, derived from the Simplified Vector Preisach model (SVPM), has individual components that like the SVPM are calculated independently using coupled selection rules for the state vector computation. However, the RVPM does not require the rotational correction. Therefore, it provides a practical alternative for computing the magnetic susceptibility using a differential approach. A vector version, using the framework of the DOK model, is implemented. Simulation results for the reduced vector Preisach model are also presented.

  20. Demonstrating Reduced Gravity.

    ERIC Educational Resources Information Center

    Pearlman, Howard; And Others

    1996-01-01

    Describes the construction of the Reduced-Gravity Demonstrator, which can be used to illustrate the effects of gravity on a variety of phenomena, including the way fluids flow, flames burn, and mechanical systems behave. Presents experiments, appropriate for classroom use, to demonstrate how the behavior of common physical systems change when…

  1. 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.

  2. 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.

  3. Reuse, Reduce, Recycle.

    ERIC Educational Resources Information Center

    Briscoe, Georgia

    1991-01-01

    Discussion of recycling paper in law libraries is also applicable to other types of libraries. Results of surveys of law libraries that investigated recycling practices in 1987 and again in 1990 are reported, and suggestions for reducing the amount of paper used and reusing as much as possible are offered. (LRW)

  4. 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. PMID:25584437

  5. Risk-reducing mastectomy.

    PubMed

    Chiesa, Federica; Sacchini, Virgilio S

    2016-10-01

    Mastectomy rates have significantly increased over the last decades, likely due to the rising trend of risk-reducing mastectomies (RRM) in the treatment and prevention of breast cancer. Growing evidence suggests that aggressive risk-reducing surgical strategies are only justified in high-risk breast cancer situations. Notably, in this selected cohort of women, prophylactic mastectomies offer evident benefit for local and contralateral disease control, and may also provide a survival benefit. Nevertheless, the extent of the increasing frequency of this operation is not explained by the broadening of the medical indications alone. Here we analyze the current evidence regarding RRM, its clinical practice, and possible explanations for the rising phenomenon of aggressive surgical locoregional control strategies. PMID:26785281

  6. 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.

  7. Reducing volcanic risk

    USGS Publications Warehouse

    Decker, R.; Decker, B.

    1991-01-01

    The last two decades have brought major advances in research on how volcanoes work and how to monitor their changing habits. Geologic mapping as well as studies of earthquake patterns and surface deformation associated with underground movement of magma have given scientists a better view of the inner structure and dynamics of active volcanoes. With the next decade, the time has come to focuses more on applying this knowledge toward reducing the risk from volcanic activity on a worldwide basis. 

  8. 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

  9. 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.

  10. Reduce energy use

    SciTech Connect

    Welch, J.B.

    1997-07-01

    With the rising costs of utilities, Crystals International, Inc. (Plant City, Fla.), a producer of freeze-dried products for the chemical process industries, was exploring various methods to reduce energy consumption. For years, the firm had been concerned about energy costs, considering that dehydration is energy-intensive, with natural gas a major item in overhead expenses. The gas is used to fire boilers and provide steam to operate jet ejectors supplied by Croll-Reynolds (Westfield, NJ), which in turn supply the vacuum for the dehydration process. In efforts to increase efficiency and save money, Crystals International decided to replace two older boilers with a single, high-capacity unit. Producing 13,800 lb/h of 200-psig steam, the unit`s main purpose was to supply the plant`s two steam ejectors and a variety of other process needs. However, with the new boiler, system pressure would be increased and the ejector nozzles would see steam at 150 psig. This was a problem since the nozzles were designed to operate at 115-psig steam. To solve the problem, a pressure reducer, placed before the steam reached the nozzles was considered. However, Crystals International determined that reducing pressure promoted formation of potentially damaging condensate. The only alternative then, was to redesign the ejectors to accept the new system parameters.

  11. Minocycline reduces ethanol drinking.

    PubMed

    Agrawal, R G; Hewetson, A; George, C M; Syapin, P J; Bergeson, S E

    2011-06-01

    Alcoholism is a disease characterized by continued alcohol consumption despite recurring negative consequences. Thus, medications that reduce the drive to consume alcohol can be beneficial in treating alcoholism. The neurobiological systems that regulate alcohol consumption are complex and not fully understood. Currently, medications are available to treat alcoholism that act either by causing accumulation of a toxic metabolite of ethanol, or by targeting specific transmitter receptors. The purpose of our study was to investigate a new potential therapeutic pathway, neuroimmune interactions, for effects on ethanol consumption. We hypothesized that neuroimmune activity of brain glia may have a role in drinking. We utilized minocycline, a second generation tetracycline antibiotic that has immune modulatory actions, to test our hypothesis because it is known to suppress microglia, and to a lesser extent astroglia, activity following many types of insults to the brain. Treatment with 50mg/kg minocycline significantly reduced ethanol intake in male and female C57Bl/6J mice using a free choice voluntary drinking model. Saline injections did not alter ethanol intake. Minocycline had little effect on water intake or body weight change. The underlying mechanism whereby minocycline reduced ethanol intake requires further study. The results suggest that drugs that alter neuroimmune pathways may represent a new approach to developing additional therapies to treat alcoholism. PMID:21397005

  12. 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.

  13. Reducing disinfectant wastage.

    PubMed

    Kaye, S B; Graham, R; McCarthy, K; Green, J R; Damjanovic, V; Austin, M

    1991-01-01

    In order to lower departmental costs in an ophthalmological outpatient department by reducing wastage, the stability of available chlorine at levels of 280 ppm and 560 ppm in litre solutions of sodium dichloroisocyanurate was investigated over a three-week period. There was no significant decay in available chlorine at these levels in solutions kept at 20 degrees C. Sodium dichloroisocyanurate may be prepared on a weekly instead of a daily basis with an annual saving of 1200 pounds to 1400 pounds. PMID:2060659

  14. 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.

  15. 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.

  16. 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.

  17. Reducing Penguin Pollution

    NASA Astrophysics Data System (ADS)

    Bhattacharya, Bhubanjyoti; Datta, Alakabha; London, David

    2013-06-01

    The most common decay used for measuring 2βs, the phase of B0s--\\bar B0s mixing, is B0s-> J/ψ φ . This decay is dominated by the color-suppressed tree diagram, but there are other contributions due to gluonic and electroweak penguin diagrams. These are often referred to as "penguin pollution" (PP) because their inclusion in the amplitude leads to a theoretical error in the extraction of 2βs from the data. In the standard model (SM), it is estimated that the PP is negligible, but there is some uncertainty as to its exact size. Now, φ sc\\bar {cs} (the measured value of 2βs) is small, in agreement with the SM, but still has significant experimental errors. When these are reduced, if one hopes to be able to see clear evidence of new physics (NP), it is crucial to have the theoretical error under control. In this paper, we show that, using a modification of the angular analysis currently used to measure φ sc\\bar {cs} in B0s-> J/ψ φ , one can reduce the theoretical error due to PP. Theoretical input is still required, but it is much more modest than entirely neglecting the PP. If φ sc\\bar {cs} differs from the SM prediction, this points to NP in the mixing. There is also enough information to test for NP in the decay. This method can be applied to all B0s/\\bar B0s -> V1 V2 decays.

  18. 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

  19. Generalized reduced MHD equations

    SciTech Connect

    Kruger, S.E.; Hegna, C.C.; Callen, J.D.

    1998-07-01

    A new derivation of reduced magnetohydrodynamic (MHD) equations is presented. A multiple-time-scale expansion is employed. It has the advantage of clearly separating the three time scales of the problem associated with (1) MHD equilibrium, (2) fluctuations whose wave vector is aligned perpendicular to the magnetic field, and (3) those aligned parallel to the magnetic field. The derivation is carried out without relying on a large aspect ratio assumption; therefore this model can be applied to any general toroidal configuration. By accounting for the MHD equilibrium and constraints to eliminate the fast perpendicular waves, equations are derived to evolve scalar potential quantities on a time scale associated with the parallel wave vector (shear-alfven wave time scale), which is the time scale of interest for MHD instability studies. Careful attention is given in the derivation to satisfy energy conservation and to have manifestly divergence-free magnetic fields to all orders in the expansion parameter. Additionally, neoclassical closures and equilibrium shear flow effects are easily accounted for in this model. Equations for the inner resistive layer are derived which reproduce the linear ideal and resistive stability criterion of Glasser, Greene, and Johnson.

  20. Cancer Reduces Transcriptome Specialization

    PubMed Central

    Martínez, Octavio; Reyes-Valdés, M. Humberto; Herrera-Estrella, Luis

    2010-01-01

    A central goal of cancer biology is to understand how cells from this family of genetic diseases undergo specific morphological and physiological changes and regress to a de-regulated state of the cell cycle. The fact that tumors are unable to perform most of the specific functions of the original tissue led us to hypothesize that the degree of specialization of the transcriptome of cancerous tissues must be less than their normal counterparts. With the aid of information theory tools, we analyzed four datasets derived from transcriptomes of normal and tumor tissues to quantitatively test the hypothesis that cancer reduces transcriptome specialization. Here, we show that the transcriptional specialization of a tumor is significantly less than the corresponding normal tissue and comparable with the specialization of dedifferentiated embryonic stem cells. Furthermore, we demonstrate that the drop in specialization in cancerous tissues is largely due to a decrease in expression of genes that are highly specific to the normal organ. This approach gives us a better understanding of carcinogenesis and offers new tools for the identification of genes that are highly influential in cancer progression. PMID:20454660

  1. 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. PMID:20510944

  2. 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).

  3. 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.

  4. Generalized reduced magnetohydrodynamic equations

    SciTech Connect

    Kruger, S.E.

    1999-02-01

    A new derivation of reduced magnetohydrodynamic (MHD) equations is presented. A multiple-time-scale expansion is employed. It has the advantage of clearly separating the three time scales of the problem associated with (1) MHD equilibrium, (2) fluctuations whose wave vector is aligned perpendicular to the magnetic field, and (3) those aligned parallel to the magnetic field. The derivation is carried out without relying on a large aspect ratio assumption; therefore this model can be applied to any general configuration. By accounting for the MHD equilibrium and constraints to eliminate the fast perpendicular waves, equations are derived to evolve scalar potential quantities on a time scale associated with the parallel wave vector (shear-Alfven wave time scale), which is the time scale of interest for MHD instability studies. Careful attention is given in the derivation to satisfy energy conservation and to have manifestly divergence-free magnetic fields to all orders in the expansion parameter. Additionally, neoclassical closures and equilibrium shear flow effects are easily accounted for in this model. Equations for the inner resistive layer are derived which reproduce the linear ideal and resistive stability criterion of Glasser, Greene, and Johnson. The equations have been programmed into a spectral initial value code and run with shear flow that is consistent with the equilibrium input into the code. Linear results of tearing modes with shear flow are presented which differentiate the effects of shear flow gradients in the layer with the effects of the shear flow decoupling multiple harmonics.

  5. Reducing gas generators and methods for generating a reducing gas

    SciTech Connect

    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.

  6. Reducing Risks of Birth Defects

    MedlinePlus

    ... Education FAQs Reducing Risks of Birth Defects Patient Education Pamphlets - Spanish Reducing Risks of Birth Defects FAQ146, February 2016 ... Your Practice Patient Safety & Quality Payment Reform (MACRA) Education & Events Annual ... Pamphlets Teen Health About ACOG About Us Leadership & ...

  7. Oxygen-reducing catalyst layer

    DOEpatents

    O'Brien, Dennis P.; Schmoeckel, Alison K.; Vernstrom, George D.; Atanasoski, Radoslav; Wood, Thomas E.; Yang, Ruizhi; Easton, E. Bradley; Dahn, Jeffrey R.; O'Neill, David G.

    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.

  8. Reducing polypharmacy in extended care.

    PubMed

    Hamdy, R C; Moore, S W; Whalen, K; Donnelly, J P; Compton, R; Testerman, F; Haulsee, P; Hughes, J

    1995-05-01

    In this 5-year prospective study, we determined the feasibility of reducing polypharmacy in a long-term care institution by a systematic review of the pharmacy records. At 6-month intervals, the computer printout of all medications prescribed to patients in a 550-bed institution was reviewed. After patients taking more than 10 different drugs were identified, their physician was notified and was asked to review their medications according to specific guidelines. The number of patients taking 10 or more medications was reduced from 67, when the program was started, to 9. The average number of medications per patient was reduced from 5.5 to 4.6. This program reduced the prevalence of polypharmacy and had long-lasting effects on the physicians' prescribing habits. We also believe it led to improved patient care by reducing the potential for drug interactions and to cost savings for the pharmacy. PMID:7732442

  9. 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...

  10. 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...

  11. 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...

  12. Reducing Childhood Obesity: We Can!

    MedlinePlus

    ... this page please turn Javascript on. Feature: Reducing Childhood Obesity We Can! Past Issues / Spring - Summer 2010 Table ... Promotes Healthier Children We Can! is a national childhood obesity prevention program sponsored by the National Heart, Lung, ...

  13. 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)

  14. 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.

  15. 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. PMID:24525378

  16. 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

  17. Reduced waste generation, FY 1986

    SciTech Connect

    Not Available

    1986-02-01

    The United States Department of Energy is committed to the principles of minimizing the quantity and transuranic content of its transuranium (TRU) waste being generated at its nuclear facilities. The reasons are to reduce costs associated with waste handling and disposal, and also to reduce radiation exposure to workers and risk for radionuclide release to man and the environment. The purpose of this document is to provide the USDOE with a plan of research and development tasks for waste minimization, and is prepared so as to provide the maximum impact on volumes based on cost/benefit factors. The document is to be updated annually or as needed to reflect current and future tasks. The Reduced Waste Generation (RWG) tasks encompass a wide range of activities with the principal goals of (1) preventing the generation of waste and (2) converting TRU waste into low-level wastes (LLW) by sorting or decontamination. Concepts for reducing the volume such as in incineration and compaction are considered within the discipline of Reduced Waste Generation, but are considered as somewhat developed technology with only a need for implementation. 33 refs.

  18. 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.

  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. 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…

  1. 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.

  2. Reducing Smoking among Pregnant Adolescents.

    ERIC Educational Resources Information Center

    Duffy, Joanne; Coates, Thomas J.

    1989-01-01

    Describes psychosocial intervention designed to reduce smoking in a group of pregnant teenagers. Five modules are presented, each being designed to heighten awareness of the issue; provide motivational messages; enhance the adolescent's social skills; and teach specific smoking-cessation skills. (Author/NB)

  3. 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.

  4. REDUCING INK AND CLEANER WASTE

    EPA Science Inventory

    Changing from alcohol-based inks and cleaners can reduce the amount and toxicity of emissions and waste, while also improving product quality and saving money. his article explores how a flexographic printer successfully made the switch without incurring significant capital costs...

  5. 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.…

  6. 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…

  7. 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.

  8. 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…

  9. Reducing Harm in Healthcare Systems.

    PubMed

    O'Brien, Tim

    2015-08-01

    An understanding of the importance of causation of medical errors is important for determining strategies to reduce the harm that they can cause to patients. This paper discusses how dentistry can learn from medicine as well as other industries when developing approaches designed to deal with the causes of errors, rather than their outcomes. PMID:26556517

  10. Reduced Order Modeling Incompressible Flows

    NASA Technical Reports Server (NTRS)

    Helenbrook, B. T.

    2010-01-01

    The details: a) Need stable numerical methods; b) Round off error can be considerable; c) Not convinced modes are correct for incompressible flow. Nonetheless, can derive compact and accurate reduced-order models. Can be used to generate actuator models or full flow-field models

  11. 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.

  12. 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.

  13. Child poverty can be reduced.

    PubMed

    Plotnick, R D

    1997-01-01

    Child poverty can be reduced by policies that help families earn more and supplement earned income with other sources of cash. A comprehensive antipoverty strategy could use a combination of these approaches. This article reviews recent U.S. experience with these broad approaches to reducing child poverty and discusses lessons from abroad for U.S. policymakers. The evidence reviewed suggests that, although policies to increase earned incomes among low-wage workers can help, these earnings gains will not be sufficient to reduce child poverty substantially. Government income support programs, tax policy, and child support payments from absent parents can be used to supplement earned incomes of poor families with children. Until recently, Aid to Families with Dependent Children (AFDC) was the main government assistance program for low-income families with children. Temporary Assistance for Needy Families (TANF) has recently replaced AFDC. This article explains why TANF benefits are likely to be less than AFDC benefits. The article also examines the effects of Social Security and Supplemental Security Income on child poverty. The most encouraging recent development in antipoverty policy has been the decline in the federal tax burden on poor families, primarily as a result of the expansion of the Earned Income Tax Credit (EITC), now the largest cash assistance program for families with children. In 1995, government transfer programs (including the value of cash, food, housing, medical care, and taxes) decreased child poverty by 38% (from 24.2% to 14.2% of children under 18). Child poverty may also be reduced by policies that increase contributions from absent single parents to support their children. Overall, evidence from the United States and other developed countries suggests that a variety of approaches to reducing child poverty are feasible. Implementation of effective programs will depend, however, on the nation's political willingness to devote more resources to

  14. Contrails reduce daily temperature range.

    PubMed

    Travis, David J; Carleton, Andrew M; Lauritsen, Ryan G

    2002-08-01

    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. PMID:12167846

  15. Reduced coking of fuel nozzles

    SciTech Connect

    Mancini, A.A.; Sager, J.W.; Kobish, T.R.

    1989-01-17

    This patent describes a fuel nozzle useful for a gas turbine engine and having a nozzle face, the combination of fuel supply means on the nozzle, the fuel supply means including an annular fuel discharge body converging in a downstream direction toward a longitudinal central axis of the nozzle and terminating in a downstream fuel discharge orifice substantially on the central axis for discharging fuel from the orifice for mixing with air downstream of the nozzle face, air supply means on the nozzle for discharging air from the nozzle face, and means on the nozzle around the fuel discharge body cooperating with the air supply means for controllably discharging sufficient air flow with locally reduced swirl strength over the fuel discharge body to establish a recirculation zone spaced away from the nozzle face downstream thereof a sufficient distance to substantially reduce coking on the nozzle face.

  16. Reduced graphene oxide molecular sensors.

    PubMed

    Robinson, Jeremy T; Perkins, F Keith; Snow, Eric S; Wei, Zhongqing; Sheehan, Paul E

    2008-10-01

    We demonstrate reduced graphene oxide as the active material for high-performance molecular sensors. Sensors are fabricated from exfoliated graphene oxide platelets that are deposited to form an ultrathin continuous network. These graphene oxide networks are tunably reduced toward graphene by varying the exposure time to a hydrazine hydrate vapor. The conductance change of the networks upon exposure to trace levels of vapor is measured as a function of the chemical reduction. The level of reduction affects both the sensitivity and the level of 1/ f noise. The sensors are capable of detecting 10 s exposures to simulants of the three main classes of chemical-warfare agents and an explosive at parts-per-billion concentrations. PMID:18763832

  17. 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

  18. 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.

  19. 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.

  20. Reduced modified Chaplygin gas cosmology

    NASA Astrophysics Data System (ADS)

    Lu, Jianbo; Geng, Danhua; Xu, Lixin; Wu, Yabo; Liu, Molin

    2015-02-01

    In this paper, we study cosmologies containing the reduced modified Chaplygin gas (RMCG) fluid which is reduced from the modified Chaplygin gas p = Aρ - Bρ -α for the value of α = -1 /2. In this special case, dark cosmological models can be realized for different values of model parameter A. We investigate the viabilities of these dark cosmological models by discussing the evolutions of cosmological quantities and using the currently available cosmic observations. It is shown that the special RMCG model ( A = 0 or A = 1) which unifies the dark matter and dark energy should be abandoned. For A = 1 /3, RMCG which unifies the dark energy and dark radiation is the favorite model according to the objective Akaike information criteria. In the case of A < 0, RMCG can achieve the features of the dynamical quintessence and phantom models, where the evolution of the universe is not sensitive to the variation of model parameters.

  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. 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%.

  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 PAGESBeta

    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 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. 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

  6. Reduced and Superreduced Diplatinum Complexes.

    PubMed

    Darnton, Tania V; Hunter, Bryan M; Hill, Michael G; Záliš, Stanislav; Vlček, Antonín; Gray, Harry B

    2016-05-01

    A d(8)-d(8) complex [Pt2(μ-P2O5(BF2)4](4-) (abbreviated Pt(pop-BF2)(4-)) undergoes two 1e(-) reductions at E1/2 = -1.68 and Ep = -2.46 V (vs Fc(+)/Fc) producing reduced Pt(pop-BF2)(5-) and superreduced Pt(pop-BF2)(6-) species, respectively. The EPR spectrum of Pt(pop-BF2)(5-) and UV-vis spectra of both the reduced and the superreduced complexes, together with TD-DFT calculations, reveal successive filling of the 6pσ orbital accompanied by gradual strengthening of Pt-Pt bonding interactions and, because of 6pσ delocalization, of Pt-P bonds in the course of the two reductions. Mayer-Millikan Pt-Pt bond orders of 0.173, 0.268, and 0.340 were calculated for the parent, reduced, and superreduced complexes, respectively. The second (5-/6-) reduction is accompanied by a structural distortion that is experimentally manifested by electrochemical irreversibility. Both reduction steps proceed without changing either d(8) Pt electronic configuration, making the superreduced Pt(pop-BF2)(6-) a very rare 6p(2) σ-bonded binuclear complex. However, the Pt-Pt σ bonding interaction is limited by the relatively long bridging-ligand-imposed Pt-Pt distance accompanied by repulsive electronic congestion. Pt(pop-BF2)(4-) is predicted to be a very strong photooxidant (potentials of +1.57 and +0.86 V are estimated for the singlet and triplet dσ*pσ excited states, respectively). PMID:27068652

  7. Combustion at reduced gravitational conditions

    NASA Technical Reports Server (NTRS)

    Berlad, A. L.; Wang, L. S.; Joshi, N.; Pai, C. I.

    1980-01-01

    The theoretical structures needed for the predictive analyses and interpretations for flame propagation and extinction for clouds of porous particulates are presented. Related combustion theories of significance to reduced gravitational studies of combustible media are presented. Nonadiabatic boundaries are required for both autoignition theory and for extinction theory. Processes that were considered include, pyrolysis and vaporization of particulates, heterogeneous and homogeneous chemical kinetics, molecular transport of heat and mass, radiative coupling of the medium to its environment, and radiative coupling among particles and volume elements of the combustible medium.

  8. 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.

  9. 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. PMID:26442341

  10. Reducing In-Stent Restenosis

    PubMed Central

    McDonald, Robert A.; Halliday, Crawford A.; Miller, Ashley M.; Diver, Louise A.; Dakin, Rachel S.; Montgomery, Jennifer; McBride, Martin W.; Kennedy, Simon; McClure, John D.; Robertson, Keith E.; Douglas, Gillian; Channon, Keith M.; Oldroyd, Keith G.; Baker, Andrew H.

    2015-01-01

    Background Drug-eluting stents reduce the incidence of in-stent restenosis, but they result in delayed arterial healing and are associated with a chronic inflammatory response and hypersensitivity reactions. Identifying novel interventions to enhance wound healing and reduce the inflammatory response may improve long-term clinical outcomes. Micro–ribonucleic acids (miRNAs) are noncoding small ribonucleic acids that play a prominent role in the initiation and resolution of inflammation after vascular injury. Objectives This study sought to identify miRNA regulation and function after implantation of bare-metal and drug-eluting stents. Methods Pig, mouse, and in vitro models were used to investigate the role of miRNA in in-stent restenosis. Results We documented a subset of inflammatory miRNAs activated after stenting in pigs, including the miR-21 stem loop miRNAs. Genetic ablation of the miR-21 stem loop attenuated neointimal formation in mice post-stenting. This occurred via enhanced levels of anti-inflammatory M2 macrophages coupled with an impaired sensitivity of smooth muscle cells to respond to vascular activation. Conclusions MiR-21 plays a prominent role in promoting vascular inflammation and remodeling after stent injury. MiRNA-mediated modulation of the inflammatory response post-stenting may have therapeutic potential to accelerate wound healing and enhance the clinical efficacy of stenting. PMID:26022821

  11. 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.

  12. Soldering Tested in Reduced Gravity

    NASA Technical Reports Server (NTRS)

    Struk, Peter M.; Pettegrew, Richard D.; Watson, J. Kevin; Down, Robert S.; Haylett, Daniel R.

    2005-01-01

    Whether used occasionally for contingency repair or routinely in nominal repair operations, soldering will become increasingly important to the success of future long-duration human space missions. As a result, it will be critical to have a thorough understanding of the service characteristics of solder joints produced in reduced-gravity environments. The National Center for Space Exploration Research (via the Research for Design program), the NASA Glenn Research Center, and the NASA Johnson Space Center are conducting an experimental program to explore the influence of reduced gravity environments on the soldering process. Solder joint characteristics that are being considered include solder fillet geometry, porosity, and microstructural features. Both through-hole (see the drawing and image on the preceding figure) and surface-mounted devices are being investigated. This effort (the low-gravity portion being conducted on NASA s KC-135 research aircraft) uses the soldering hardware currently available on the International Space Station. The experiment involves manual soldering by a contingent of test operators, including both highly skilled technicians and less skilled individuals to provide a skill mix that might be encountered in space mission crews. The experiment uses both flux-cored solder and solid-core solder with an externally applied flux. Other experimental parameters include the type of flux, gravitational level (nominally zero,

  13. Reduced Prefrontal Connectivity in Psychopathy

    PubMed Central

    Motzkin, Julian C.; Newman, Joseph P.; Kiehl, Kent A.; Koenigs, Michael

    2012-01-01

    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. PMID:22131397

  14. Reducing haemodialysis access infection rates.

    PubMed

    Dorman, Amanda; Dainton, Marissa

    Infections are the second most common cause of vascular access loss in the long-term haemodialysis patient, and recent years have seen an increase in healthcare-associated infections (HCAIs) associated with vascular access (Suhail, 2009). There have been a number of drivers including publication guidelines (Department of Health, 2006; 2007) and local protocols providing evidence-based recommendations that, when implemented, can reduce the risk of these infections. In England, the selection of bloodstream infections caused by methicillin resistant staphylococcus aureus (MRSA) as a significant clinical outcome has led to a vast amount of work in this area. Root cause analysis of individual infections (by the clinical teams when these occur) in many specialities identified areas where practice could be improved, including practice relating to vascular access within the renal setting. Manufacturers have also supported this work by focusing on developing products that are designed to reduce the likelihood of infections occurring. One product identified and used within the NHS is Chloraprep. PMID:21646994

  15. Vaginal douching and reduced fertility.

    PubMed Central

    Baird, D D; Weinberg, C R; Voigt, L F; Daling, J R

    1996-01-01

    OBJECTIVES: This study investigated douching and reduced fertility. METHODS: The monthly probability of conception for douchers and nondouchers was compared in a sample of 840 married, parous women in King County, Washington. Data on the number of months required to conceive were analyzed. RESULTS: In comparison with nondouchers, women who douched were 30% less likely to become pregnant each month they attempted pregnancy. This relationship remained after adjustment for covariates, and it could not be explained by women douching for medical reasons. The reduction was not related to the type of douching preparation used. Young women who douched had significantly greater reductions in monthly fertility than older women (50% reduction for women 18 to 24 years old, 29% reduction for women 25 to 29 years old, and 6% reduction for women 30 to 39 years old). CONCLUSIONS: Douching was associated with reduced fertility. Further research is needed to determine whether the relationship is casual and, if so, to what extent it is mediated by pelvic infection. In the meantime, women should be informed that douching may have adverse effects. PMID:8659660

  16. 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.

  17. Reduced gravity multibody dynamics testing

    NASA Technical Reports Server (NTRS)

    Sillanpaa, Meija

    1993-01-01

    The Final Report on reduced gravity multibody dynamics testing is presented. Tests were conducted on board the NASA KC-135 RGA in Houston, Texas. The objective was to analyze the effects of large angle rotations on flexible, multi-segmented structures. The flight experiment was conducted to provide data which will be compared to the data gathered from ground tests of the same configurations. The flight and ground tested data will be used to validate the TREETOPS software, software which models dynamic multibody systems, and other multibody codes. The flight experiment consisted of seven complete flights on board the KC-135 RGA during two one-week periods. The first period of testing was 4-9 Apr. 1993. The second period of testing was 13-18 Jun. 1993.

  18. Methods for Reducing Hydrogen Outgassing

    NASA Astrophysics Data System (ADS)

    Dong, Changkun; Mehrotra, Parixit; Myneni, Ganapati Rao

    2003-07-01

    Achieving Ultra High and Extreme High Vacuum without high temperature bakeouts is becoming essential in many applications. In this study, we investigated the use of inexpensive silica and titanium oxide thin film coatings on vacuum chambers/components to reduce the adsorption of water on the chamber walls. Water can be cracked into oxygen and hydrogen in the material and act as one of the sources of hydrogen. The measured outgassing rates of the stainless steel chambers with the thin film barrier coatings are in the range 1×10-12 Torr 1/s cm2 to 2.5×10-13 Torr 1/s cm2. We have also backed the turbo pump with an ion pump to understand and plan for fast pump down of vacuum systems.

  19. 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. PMID:25125931

  20. 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. PMID:14631879

  1. 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.

  2. 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.

  3. 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

  4. Family planning is reducing abortions.

    PubMed

    Clinton, H R

    1997-01-01

    This news brief presents the US President's wife's statement on the association between use of family planning and a decline in abortions worldwide. Hillary Rodham Clinton attended the Sixth Conference of Wives of Heads of State and Government of the Americas held in La Paz, Bolivia. The conference was suitably located in Bolivia, a country with the highest rates of maternal mortality in South America. Bolivia has responded by launching a national family planning campaign coordinated between government, nongovernmental, and medical organizations. Half of Bolivian women experience pregnancy and childbirth without the support of trained medical staff. Mortality from abortion complications account for about half of all maternal deaths in Bolivia. Voluntary family planning workers teach women about the benefits of child spacing, breast feeding, nutrition, prenatal and postpartum care, and safe deliveries. Bolivia has succeeded in increasing its contraceptive use rates and decreasing the number of safe and unsafe abortions. Bolivia's program effort was supported by USAID. USAID provided technical assistance and funds for the establishment of a network of primary health care clinics. Mrs. Clinton visited one such clinic in a poor neighborhood in La Paz, which in its first six months of operation provided 2200 consultations, delivered 200 babies, registered 700 new family planning users, and immunized 2500 children. Clinics such as this one will be affected by the US Congress's harsh cuts in aid, which reduce funding by 35% and delay program funding by 9 months. These US government cuts in foreign aid are expected to result in an additional 1.6 million abortions, over 8000 maternal deaths, and 134,000 infant deaths in developing countries. An investment in population assistance represents a sensible, cost-effective, and long-term strategy for improving women's health, strengthening families, and reducing abortion. PMID:12293000

  5. 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

  6. 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.

  7. 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.

  8. 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. PMID:15683074

  9. Reduce costs with vacuum excavation

    SciTech Connect

    Vitale, S.A.

    1983-09-01

    Although vacuum excavation equipment and methods are in their infancy, this developing technology offers tremendous promise for the future. The author explains Brooklyn Union Gas Co.'s experience with five vacuum trucks and the procedures that are used. In recent years, the higher cost of natural gas has increased the need for gas utilities to reduce their operating expenses. One way, which has been successful at Brooklyn Union Gas, is the use of vacuum excavation. Although vacuum excavation equipment and techniques are in their infancy, this developing technology offers substantial savings today and tremendous promise for the future. Brooklyn Union started its vacuum digging program by locating keyhole cutoffs--small surface openings ranging from 1 ft by 1 ft to 1 1/2 ft by 1 1/2 ft (0.3 m to 0.45 m square). It is no easy task to accurately locate a service that was installed 60 years ago. Reading the street indications, locating an existing curb valve or repair opening, gaining access to the building, making a physical lineup, and using an M-scope, plus any other tools available, have produced a high success rate.

  10. Burner retrofits reduce brewery emissions

    SciTech Connect

    Not Available

    1993-04-01

    In 1988, the South Coast Air Quality Management District in California (SCAQMD) tightened its grip on industrial emissions of nitrogen oxides (NOx). The new statute, Rule 1146, mandates a 75% reduction in NOx emissions over a five-year period ending this July. Anheuser-Busch Inc.'s second-largest brewery in Van Nuys fell under the new law's jurisdiction. Under the new law, the maximum allowable NOx emission must be reduced from 120 to 30 ppm for the two largest boilers. There were two alternatives: either prevent its formation inside the boiler, or remove it from the off-gases via selective catalytic reduction (SCR) or selective non-catalytic reduction (SNCR). Prevention was chosen, because the NOx-removal technologies are unproven in the US on natural-gas-fired boilers. In addition, it was not known whether SCR or SNCR could respond to the wide swings in boiler demand. At any given time, loads between 30 and 100% of capacity would be required from the boilers. The brewery retrofitted the 125,000-lb/h boilers with Variflame burners, based upon an earlier retrofit at Anheuser-Busch's Merrimack, N.H., brewery. The paper describes this burner and its performance.

  11. The present state of the automated micronucleus test for lymphocytes.

    PubMed

    Tates, A D; van Welie, M T; Ploem, J S

    1990-11-01

    This minireview presents the state of the art with respect to automated detection of micronuclei (MN) in binucleated lymphocytes. Emphasis is on an image analysis technique, based on the principles of mathematical morphology (pattern recognition), which combines a personal computer with an image processing board and a board for microscope control. The basic idea behind this procedure is that nuclei plus MN and cytoplasms are analysed separately and sequentially by capturing images from gallocyanin-stained nuclei plus MN and naphthol yellow-S stained cytoplasms from one microscope field by using different filters. Major steps in the identification of nuclei and MN are separation of nuclei and MN from background by determination of periphery of the nuclei and MN, and artefact rejection procedures. After changing the filter, a binary image is constructed from cytoplasms and artefacts. Finally, stored information from selected binucleated objects with/without MN is combined with the cytoplasm image to check whether selected objects belong to the same cytoplasm. The procedure described above allows automated detection of binucleated lymphocytes with or without MN. The current capacity to detect 63% of binucleated cells and 57% of the MN within them is quite acceptable. To avoid false positives, artefact rejection procedures need to be improved before the method can be used routinely. PMID:1977825

  12. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... information on this test guideline, the following references should be consulted. (1) 40 CFR 798.5395, In Vivo... mammalian cells. As the erythroblast develops into an erythrocyte (red blood cell), its main nucleus is... micronuclei is facilitated in these cells because they lack a main nucleus. (b) Definitions. For the...

  13. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... marrow erythroblast develops into a polychromatic erythrocyte, the main nucleus is extruded; any... micronuclei is facilitated in these cells because they lack a main nucleus. An increase in the frequency of... chromosomes to the poles of the daughter cells. Micronuclei are small nuclei, separate from and additional...

  14. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... marrow erythroblast develops into a polychromatic erythrocyte, the main nucleus is extruded; any... micronuclei is facilitated in these cells because they lack a main nucleus. An increase in the frequency of... chromosomes to the poles of the daughter cells. Micronuclei are small nuclei, separate from and additional...

  15. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... information on this test guideline, the following references should be consulted. (1) 40 CFR 798.5395, In Vivo... mammalian cells. As the erythroblast develops into an erythrocyte (red blood cell), its main nucleus is... micronuclei is facilitated in these cells because they lack a main nucleus. (b) Definitions. For the...

  16. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... information on this test guideline, the following references should be consulted. (1) 40 CFR 798.5395, In Vivo... mammalian cells. As the erythroblast develops into an erythrocyte (red blood cell), its main nucleus is... micronuclei is facilitated in these cells because they lack a main nucleus. (b) Definitions. For the...

  17. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... marrow erythroblast develops into a polychromatic erythrocyte, the main nucleus is extruded; any... micronuclei is facilitated in these cells because they lack a main nucleus. An increase in the frequency of... chromosomes to the poles of the daughter cells. Micronuclei are small nuclei, separate from and additional...

  18. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... information on this test guideline, the following references should be consulted. (1) 40 CFR 798.5395, In Vivo... mammalian cells. As the erythroblast develops into an erythrocyte (red blood cell), its main nucleus is... micronuclei is facilitated in these cells because they lack a main nucleus. (b) Definitions. For the...

  19. 40 CFR 79.64 - In vivo micronucleus assay.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... information on this test guideline, the following references should be consulted. (1) 40 CFR 798.5395, In Vivo... mammalian cells. As the erythroblast develops into an erythrocyte (red blood cell), its main nucleus is... micronuclei is facilitated in these cells because they lack a main nucleus. (b) Definitions. For the...

  20. 40 CFR 799.9539 - TSCA mammalian erythrocyte micronucleus test.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... marrow erythroblast develops into a polychromatic erythrocyte, the main nucleus is extruded; any... micronuclei is facilitated in these cells because they lack a main nucleus. An increase in the frequency of... chromosomes to the poles of the daughter cells. Micronuclei are small nuclei, separate from and additional...

  1. 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. PMID:22683486

  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. 40 CFR 1500.4 - Reducing paperwork.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Reducing paperwork. 1500.4 Section 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...

  4. Reduced fidelity in the Kitaev honeycomb model

    SciTech Connect

    Wang, Zhi; Ma, Tianxing; Gu, Shi-Jian; Lin, Hai-Qing

    2010-06-15

    We study reduced fidelity and reduced fidelity susceptibility in the Kitaev honeycomb model. It is shown that the nearest-two-site reduced fidelity susceptibility manifests itself as a peak at the quantum phase transition point, although the one-site reduced fidelity susceptibility vanishes. Our results directly reveal that the reduced fidelity susceptibility can be used to characterize the quantum phase transition in the Kitaev honeycomb model, which suggests that, despite its local nature, the reduced fidelity susceptibility is an accurate marker of the topological phase transition when it is properly chosen.

  5. Would Weaker Beer Help Reduce Alcohol's Harms?

    MedlinePlus

    ... medlineplus.gov/news/fullstory_160387.html Would Weaker Beer Help Reduce Alcohol's Harms? Researchers say drinkers wouldn' ... 2016 (HealthDay News) -- Lowering the alcohol content in beer and other drinks may help reduce their harmful ...

  6. Microwave Antenna With Reduced Noise Leakage

    NASA Technical Reports Server (NTRS)

    Cha, A. G.

    1986-01-01

    Gain or gain-to-temperature ratio of dual-shaped subreflector receiving antenna increased when illumination is tapered near aperture edge. Taper imposed in antenna feed reduces spillover in transmitting mode and reduces noise pickup in receiving mode.

  7. 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)

  8. 40 CFR 1500.5 - Reducing delay.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Reducing delay. 1500.5 Section 1500.5 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.5 Reducing delay. Agencies shall reduce delay by: (a) Integrating the NEPA process into early planning (§...

  9. 40 CFR 1500.5 - Reducing delay.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Reducing delay. 1500.5 Section 1500.5 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.5 Reducing delay. Agencies shall reduce delay by: (a) Integrating the NEPA process into early planning (§...

  10. 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...

  11. 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... 1 § 582.5375 Iron reduced. (a) Product. Iron reduced. (b) Conditions of use. This substance...

  12. 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... 1 § 582.5375 Iron reduced. (a) Product. Iron reduced. (b) Conditions of use. This substance...

  13. 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...

  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... 1 § 582.5375 Iron reduced. (a) Product. Iron reduced. (b) Conditions of use. This substance...

  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... 1 § 582.5375 Iron reduced. (a) Product. Iron reduced. (b) Conditions of use. This substance...

  16. 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.

  17. 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.

  18. Nitrate reduction in sulfate-reducing bacteria.

    PubMed

    Marietou, Angeliki

    2016-08-01

    Sulfate-reducing bacteria (SRBs) gain their energy by coupling the oxidation of organic substrate to the reduction of sulfate to sulfide. Several SRBs are able to use alternative terminal electron acceptors to sulfate such as nitrate. Nitrate-reducing SRBs have been isolated from a diverse range of environments. In order to be able to understand the significance of nitrate reduction in SRBs, we need to examine the ecology and physiology of the nitrate-reducing SRB isolates. PMID:27364687

  19. 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)

  20. 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,…

  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. Subsurface manure application to reduce ammonia emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Incorporation into soil is generally recommended to reduce ammonia volatilization and nutrient runoff following land application of manures. A range of subsurface applicators are available for manure incorporation with minimal soil disturbance in reduced tillage systems, but none have been widely a...

  3. 49 CFR 609.23 - Reduced fare.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 7 2011-10-01 2011-10-01 false Reduced fare. 609.23 Section 609.23 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRANSPORTATION FOR ELDERLY AND HANDICAPPED PERSONS § 609.23 Reduced fare. Applicants for...

  4. 49 CFR 609.23 - Reduced fare.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 7 2013-10-01 2013-10-01 false Reduced fare. 609.23 Section 609.23 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRANSPORTATION FOR ELDERLY AND HANDICAPPED PERSONS § 609.23 Reduced fare. Applicants for...

  5. 49 CFR 609.23 - Reduced fare.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 7 2014-10-01 2014-10-01 false Reduced fare. 609.23 Section 609.23 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL TRANSIT ADMINISTRATION, DEPARTMENT OF TRANSPORTATION TRANSPORTATION FOR ELDERLY AND HANDICAPPED PERSONS § 609.23 Reduced fare. Applicants for...

  6. NATURAL RELATIONSHIPS AMONG SULFATE-REDUCING EUBACTERIA

    EPA Science Inventory

    Phylogenetic relationships among 20 nonsporeforming and two endospore-forming species of sulfate-reducing eubacteria were inferred from comparative 16S rRNA seguencing. ll genera of mesophilic sulfate-reducing eubacteria except the new genus Desulfomicrobium and the gliding Desul...

  7. 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…

  8. Methods To Reduce Soil Fumigation Emissions

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Soil fumigation is an important management practice for controlling soil pests in many high value crops including almonds. Reducing atmospheric emissions is necessary to minimize the environmental impact of soil fumigation. Water seals (sprinkling water on soil surface) to reduce fumigant emissions...

  9. 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…

  10. Sludge displacement verification for reducing grout report

    SciTech Connect

    Caldwell, T.B.; Langton, C.A.

    1997-04-10

    To support the closure of HLW tanks at SRS, a reducing grout was developed that is formulated to reduce the mobility of radionuclides left in each tank. During non-radioactive flow tests of the grout, it was discovered that, in addition to its desired properties, the grout has the ability to move residual waste a considerable distance across the tank floor.

  11. Reducing Class Size To Increase Student Involvement.

    ERIC Educational Resources Information Center

    Lottes, Christine R.

    Reducing class size was considered an important element in a revised health course at Gettysburg College (Pennsylvania). However, reducing class size to approximately 15 students per class would require 38 sections, more than the health faculty could handle. To recruit additional instructors, the course was marketed to faculty and administrators…

  12. 40 CFR 1500.5 - Reducing delay.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Reducing delay. 1500.5 Section 1500.5 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.5 Reducing... do not individually or cumulatively have a significant effect on the human environment (§ 1508.4)...

  13. 40 CFR 1500.5 - Reducing delay.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Reducing delay. 1500.5 Section 1500.5 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.5 Reducing... do not individually or cumulatively have a significant effect on the human environment (§ 1508.4)...

  14. 40 CFR 1500.5 - Reducing delay.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Reducing delay. 1500.5 Section 1500.5 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.5 Reducing... do not individually or cumulatively have a significant effect on the human environment (§ 1508.4)...

  15. [Discussion on twirling reinforcing-reducing method].

    PubMed

    Shen, Te-Li

    2014-01-01

    The essence of twirling reinforcing-reducing method is discussed to provide theoretical guidance for clinical application of reinforcing-reducing method. Through retrospection on historical literature of twirling reinforcing-reducing method, records and explanatory notes are thoroughly explored. Several existing opinions are analyzed and explained for instance twirling method has connection with circulation direction of channels; twirling method is subdivided into right and left, male and female, hand and foot; twriling method is related to quantity of stimulus and operation time; twriling method belongs to spiral motion and so on. As a result, it is found that the key of twirling reinforcing-reducing method is the posture of needle-holding hand that defines three-dimensional motion. If twirling method is subdivided into right and left, male and female, hand and foot and so on, steric effects of lifting-thrusting movement that come along with twirling method could be ignored at the same time. It is that the essence of twirling reinforcing-reducing method is close to the principle of lifting-thrusting reinforcing-reducing method, enriching effect with slow insertion and fast withdrawal of needle while reducing effect with fast insertion and slow withdrawal, which is recorded in Miraculous Pivot: Nine needle and Twelve Yuan. With this principle as guide, manipulation could be avoided to become a mere formality and illusory metaphysics during clinical application of twirling reinforcing-reducing method. PMID:24673057

  16. 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 ...

  17. Reduced hydrogen permeability at high temperatures

    NASA Technical Reports Server (NTRS)

    Stephens, J. R.; Klopp, W. D.; Misencik, J. A.

    1981-01-01

    CO and CO2 reduce hydrogen loss through iron, nickel, and cobalt based alloy tubes. Method is based on concept that oxide film on metal surface reduces hydrogen permeability through metal; adding CO or CO2 forms oxide films continuously during operation, and hydrogen containment is improved. Innovation enhances prospects for Stirling engine system utilization.

  18. Uranium reduction and resistance to reoxidation under iron-reducing and sulfate-reducing conditions.

    PubMed

    Boonchayaanant, Benjaporn; Nayak, Dipti; Du, Xin; Criddle, Craig S

    2009-10-01

    Oxidation and mobilization of microbially-generated U(IV) is of great concern for in situ uranium bioremediation. This study investigated the reoxidation of uranium by oxygen and nitrate in a sulfate-reducing enrichment and an iron-reducing enrichment derived from sediment and groundwater from the Field Research Center in Oak Ridge, Tennessee. Both enrichments were capable of reducing U(VI) rapidly. 16S rRNA gene clone libraries of the two enrichments revealed that Desulfovibrio spp. are dominant in the sulfate-reducing enrichment, and Clostridium spp. are dominant in the iron-reducing enrichment. In both the sulfate-reducing enrichment and the iron-reducing enrichment, oxygen reoxidized the previously reduced uranium but to a lesser extent in the iron-reducing enrichment. Moreover, in the iron-reducing enrichment, the reoxidized U(VI) was eventually re-reduced to its previous level. In both, the sulfate-reducing enrichment and the iron-reducing enrichment, uranium reoxidation did not occur in the presence of nitrate. The results indicate that the Clostridium-dominated iron-reducing communities created conditions that were more favorable for uranium stability with respect to reoxidation despite the fact that fewer electron equivalents were added to these systems. The likely reason is that more of the added electrons are present in a form that can reduce oxygen to water and U(VI) back to U(IV). PMID:19651424

  19. 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.

  20. 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. PMID:25585767

  1. 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.

  2. A Home Visit Checklist to Reduce Rehospitalizations.

    PubMed

    Wood, Sharon L

    2015-09-01

    Hospital readmission rates have become the subject of national attention among healthcare providers. Home healthcare agencies work to bridge the gap between hospital and home/community, and share a vested interest in reducing hospital readmissions. Evidence supports the use of checklists to improve safety and decrease risk by reducing errors of omission, facilitating communication and improving clinician accountability. This article proposes that the use of checklists in home healthcare agencies may reduce rehospitalizations, and presents the experience of a large home healthcare agency's creation and implementation of a pilot study to introduce a home visit checklist. PMID:26323007

  3. 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...

  4. Weight Loss Might Reduce Cancer Risk

    MedlinePlus

    ... evidence in the jigsaw of the benefits of losing weight, and how important weight loss is to ... Hutchinson Cancer Research Center in Seattle. In general, losing weight reduces the risk of breast, colon and ...

  5. 76 FR 6123 - Reducing Regulatory Burden

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-02-03

    ... achieving its regulatory objectives. DATES: Written comments and information are requested on or before... the least burden on society, consistent with obtaining the regulatory objectives, taking into account... approaches that reduce burdens and maintain flexibility. Regulations be guided by objective...

  6. 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

  7. Composite seal reduces alkaline battery leakage

    NASA Technical Reports Server (NTRS)

    Clatterbuck, C. H.; Plitt, K. F.

    1965-01-01

    Composite seal consisting of rubber or plastic washers and a metal washer reduces alkaline battery leakage. Adhesive is applied to each washer interface, and the washers are held together mechanically.

  8. Galvanic corrosion reduced in aluminum fabrications

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Titanium alloy fasteners dipped at zinc chromate primer are installed while wet in protective coated aluminum panels to reduce galvanic corrosion. Moisture tight seals at fastener points are also provided.

  9. Sting of Shingles: Vaccine, Treatments Reduce Risks

    MedlinePlus

    ... our exit disclaimer . Subscribe The Sting of Shingles Vaccine, Treatments Reduce Risks If you’ve ever had ... someone who’s never had chickenpox or a chickenpox vaccine. If that happens, the other person would get ...

  10. 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...

  11. 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.

  12. Spontaneously reduced isolated orbital roof fracture.

    PubMed

    Itinteang, Tinte; Lambe, Gerald Francis; MacKinnon, Craig; Agir, Hakan

    2012-07-01

    We report a case of a spontaneously reduced isolated orbital roof blow-in fracture with resolution of associated diplopia and blepharoptosis highlighting the need for a low threshold for reimaging this cohort of facial fracture patients. PMID:22801127

  13. 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.

  14. Reducing redundancy in wireless capsule endoscopy videos.

    PubMed

    Lee, Hyun-Gyu; Choi, Min-Kook; Shin, Byeong-Seok; Lee, Sang-Chul

    2013-07-01

    We eliminate similar frames from a wireless capsule endoscopy video of the human intestines to maximize spatial coverage and minimize the redundancy in images. We combine an intensity correction method with a method based an optical flow and features to detect and reduce near-duplicate images acquired during the repetitive backward and forward egomotions due to peristalsis. In experiments, this technique reduced duplicate image of 52.3% from images of the small intestine. PMID:23668342

  15. HSCT design for reduced sonic boom

    NASA Technical Reports Server (NTRS)

    Haglund, George T.

    1992-01-01

    The topics covered include the following: low sonic boom design perspective; design approach for reduced sonic boom; target sonic boom waveforms; airplane design for reduced sonic boom loudness; design procedure for low sonic boom; wing design and nacelle lift effects; area distributions and F-functions due to volume; fuselage area distributions; low sonic boom design, configuration 3B; sonic boom characteristics; sizing, performance, and noise characteristics; a summary of phase 3 configurations; impact of sonic boom design constraints; and wing loading considerations.

  16. Laser welding in a reduced gravity environment

    NASA Technical Reports Server (NTRS)

    Workman, Gary L.; Kaukler, William F.

    1992-01-01

    Preliminary results on the effects of reduced gravity on laser welding of stainless steel and other materials are reported. Laser welding experiments using a low power (10-18 watts) Nd-YAG laser have been performed on the NASA KC-135, which flies parabolic maneuvers to simulate reduced gravity conditions. Experiments on 0.005-0.010 inch thick stainless steel samples displayed a pronounced change in weld bead width, depth of penetration and surface ripple with changes in gravity level.

  17. 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. PMID:22049674

  18. New approaches to reduce radiation exposure.

    PubMed

    Hill, Kevin D; Einstein, Andrew J

    2016-01-01

    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

  19. Reducing mode circulating fluid bed combustion

    DOEpatents

    Lin, Yung-Yi; Sadhukhan, Pasupati; Fraley, Lowell D.; Hsiao, Keh-Hsien

    1986-01-01

    A method for combustion of sulfur-containing fuel in a circulating fluid bed combustion system wherein the fuel is burned in a primary combustion zone under reducing conditions and sulfur captured as alkaline sulfide. The reducing gas formed is oxidized to combustion gas which is then separated from solids containing alkaline sulfide. The separated solids are then oxidized and recycled to the primary combustion zone.

  20. Quantitative analysis of cellulose-reducing ends.

    PubMed

    Kongruang, Sasithorn; Han, Myung Joo; Breton, Claudia Isela Gil; Penner, Michael H

    2004-01-01

    Methods for the quantification of total and accessible reducing ends on traditional cellulose substrates have been evaluated because of their relevance to enzyme-catalyzed cellulose saccharificaion. For example, quantification of accessible reducing ends is likely to be the most direct measure of substrate concentration for the exo-acting, reducing end-preferring cellobiohydrolases. Two colorimetric assays (dinitrosalicylic acid [DNS] and bicinchoninic acid [BCA] assay ) and a radioisotope approach (NaB3H4 labeling) were evaluated for this application. Cellulose substrates included microcrystalline celluloses, bacterial celluloses, and filter paper. Estimates of the number of reducing ends per unit mass cellulose were found to be dependent on the assay system (i.e. the DNS and BCA assays gave strikingly different results). DNS-based values were several-fold higher than those obtained using the BCA assay, with fold-differences being substrate specific. Sodium borohydride reduction of celluloses, using cold or radiolabeled reagent under relatively mild conditions, was used to assess the number of surface (solvent-accessible) reducing ends. The results indicate that 30-40% of the reducing ends on traditional cellulose substrates are not solvent accessible; that is, they are buried in the interior of cellulose structures and thus not available to exo-acting enzymes. PMID:15054208

  1. Reduced chemical kinetic mechanisms for hydrocarbon fuels

    SciTech Connect

    Montgomery, C J; Cremer, M A; Heap, M P; Chen, J -Y; Westbrook, C K; Maurice, L Q

    1999-12-10

    Using CARM (Computer Aided Reduction Method), a computer program that automates the mechanism reduction process, a variety of different reduced chemical kinetic mechanisms for ethylene and n-heptane have been generated. The reduced mechanisms have been compared to detailed chemistry calculations in simple homogeneous reactors and experiments. Reduced mechanisms for combustion of ethylene having as few as 10 species were found to give reasonable agreement with detailed chemistry over a range of stoichiometries and showed significant improvement over currently used global mechanisms. The performance of reduced mechanisms derived from a large detailed mechanism for n-heptane was compared to results from a reduced mechanism derived from a smaller semi-empirical mechanism. The semi-empirical mechanism was advantageous as a starting point for reduction for ignition delay, but not for PSR calculations. Reduced mechanisms with as few as 12 species gave excellent results for n-heptane/air PSR calculations but 16-25 or more species are needed to simulate n-heptane ignition delay.

  2. Melanocortin 1 Receptor Agonists Reduce Proteinuria

    PubMed Central

    Ebefors, Kerstin; Johansson, Martin E.; Stefánsson, Bergur; Granqvist, Anna; Arnadottir, Margret; Berg, Anna-Lena; Nyström, Jenny; Haraldsson, Börje

    2010-01-01

    Membranous nephropathy is one of the most common causes of nephrotic syndrome in adults. Recent reports suggest that treatment with adrenocorticotropic hormone (ACTH) reduces proteinuria, but the mechanism of action is unknown. Here, we identified gene expression of the melanocortin receptor MC1R in podocytes, glomerular endothelial cells, mesangial cells, and tubular epithelial cells. Podocytes expressed most MC1R protein, which colocalized with synaptopodin but not with an endothelial-specific lectin. We treated rats with passive Heymann nephritis (PHN) with MS05, a specific MC1R agonist, which significantly reduced proteinuria compared with untreated PHN rats (P < 0.01). Furthermore, treatment with MC1R agonists improved podocyte morphology and reduced oxidative stress. In summary, podocytes express MC1R, and MC1R agonism reduces proteinuria, improves glomerular morphology, and reduces oxidative stress in nephrotic rats with PHN. These data may explain the proteinuria-reducing effects of ACTH observed in patients with membranous nephropathy, and MC1R agonists may provide a new therapeutic option for these patients. PMID:20507942

  3. 31 CFR 561.328 - Reduce significantly, significantly reduced, and significant reduction.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 31 Money and Finance:Treasury 3 2013-07-01 2013-07-01 false Reduce significantly, significantly reduced, and significant reduction. 561.328 Section 561.328 Money and Finance: Treasury Regulations... IRANIAN FINANCIAL SANCTIONS REGULATIONS General Definitions § 561.328 Reduce significantly,...

  4. 31 CFR 561.328 - Reduce significantly, significantly reduced, and significant reduction.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 31 Money and Finance:Treasury 3 2014-07-01 2014-07-01 false Reduce significantly, significantly reduced, and significant reduction. 561.328 Section 561.328 Money and Finance: Treasury Regulations... IRANIAN FINANCIAL SANCTIONS REGULATIONS General Definitions § 561.328 Reduce significantly,...

  5. Evolution of technetium speciation in reducing grout

    SciTech Connect

    Lukens, Wayne W.; Bucher, Jerome J.; Shuh, David K.; Edelstein,Norman M.

    2003-11-24

    Cementitious waste forms (CWFs) are an important component of the strategy to immobilize high-level nuclear waste resulting from plutonium production by the U.S. Department of Energy (DOE). Technetium (99Tc) is an abundant fission product of particular concern in CWFs due to the high solubility and mobility of pertechnetate, TcO4-, the stable form of technetium in aerobic environments. CWFs can more effectively immobilize 99Tc if they contain additives that reduce mobile TcO4- to immobile Tc(IV) species. Leaching of 99Tc from reducing CWFs that contain Tc(IV) is much slower than for CWFs containing TcO4-. Previous X-ray absorption fine structure (XAFS) studies showed that the Tc(IV) species were oxidized to TcO4- in reducing grout samples prepared on a laboratory scale. Whether the oxidizer was atmospheric O2 or NO3- in the waste simulant was not determined. In actual CWFs, rapid oxidation of Tc(IV) by NO3- would be a concern, whereas oxidation by atmospheric O2 would be of less concern due to the slow diffusion and reaction of O2 with the reducing CWF. To address this uncertainty, two series of reducing grouts were prepared using TcO4- containing waste simulants with and without NO3-. In the first series of samples, the TcO4- was completely reduced using Na2S, and the samples were placed in containers that permitted O2 diffusion. In these samples, all of the technetium was initially present as aTc(IV) sulfide compound, TcSx, which was characterized using extended X-ray absorption fine structure (EXAFS) spectroscopy, and is likely Tc2S7. The TcSx initially present in the grout samples was steadily oxidized over 4 years. In the second series of samples, all of the TcO4- was not initially reduced, and the grout samples were placed in airtight containers. In these samples, the remaining TcO4- continued to be reduced as the samples aged, presumably due to the presence of reducing blast furnace slag. When samples in the second series were exposed to atmosphere, the

  6. 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

  7. Hazmat review reduces risk and improves operations

    SciTech Connect

    Hartley, P.W.; Trecha, S.J.; Patterson, P.

    1996-07-01

    Through its hazardous materials (hazmat) review initiative, Wisconsin Power and Light Co. (WP and L) repositioned itself for better plant operations while reducing the overall risks and costs associated with hazmats. The utility focused on two primary hazmat improvement objectives: (1) ensure plant hazmat operations are meeting regulatory requirements, optimizing the use, storage, and disposal of hazmats; (2) reduce the overall risk and investment associated with hazmat substances on the plant properties. ``Hazardous materials management is often overlooked as an integral component of the overall purchasing and materials management process``, emphasized Jill Doucette, WP and L Strategic Sourcing Initiative manager. ``Improved performance in this area can significantly reduce personnel and company risks, improve customer service and save dollars.``

  8. Arbuscular Mycorrhizas Reduce Nitrogen Loss via Leaching

    PubMed Central

    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. PMID:22253790

  9. 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.

  10. 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.

  11. 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.

  12. Reducing the convective losses of cavity receivers

    NASA Astrophysics Data System (ADS)

    Flesch, Robert; Grobbel, Johannes; Stadler, Hannes; Uhlig, Ralf; Hoffschmidt, Bernhard

    2016-05-01

    Convective losses reduce the efficiency of cavity receivers used in solar power towers especially under windy conditions. Therefore, measures should be taken to reduce these losses. In this paper two different measures are analyzed: an air curtain and a partial window which covers one third of the aperture opening. The cavity without modifications and the usage of a partial window were analyzed in a cryogenic wind tunnel at -173°C. The cryogenic environment allows transforming the results from the small model cavity to a large scale receiver with Gr≈3.9.1010. The cavity with the two modifications in the wind tunnel environment was analyzed with a CFD model as well. By comparing the numerical and experimental results the model was validated. Both modifications are capable of reducing the convection losses. In the best case a reduction of about 50 % was achieved.

  13. 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. PMID:24161300

  14. 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. PMID:24320065

  15. 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.

  16. Outcomes of a program to reduce depression.

    PubMed

    Kim, Gyung Hee; Kim, Kyeha; Park, Hyojung

    2011-06-01

    Depression is increasing among Korean college students. Moreover, it is common for depressed individuals to consider attempting suicide. The purpose of this study therefore was to develop and examine the effectiveness of an intervention to reduce suicidal ideation and depression among female college students. Study participants were assigned to either an intervention (n = 27) or control (n = 31) group. The intervention group received a depression-reducing program in eight 1-hr weekly sessions. Measures of suicidal ideation and depression were administered. The program has effects on suicidal ideation and depression among female college students. The findings suggest that the study program may be useful in reducing suicidal ideation and depression among female college students. PMID:21078916

  17. 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.

  18. Alternatives for reducing hot-water bills

    SciTech Connect

    Bennington, G.E.; Spewak, P.C.

    1981-06-01

    A two stage approach to reducing residential water heating bills is described. In Stage I, simple conservation measures were included to reduce the daily hot water energy consumption and the energy losses from the water tank. Once these savings are achieved, Stage II considers more costly options for further reducing the water heating bill. Four alternatives are considered in Stage II: gas water heaters; solar water heaters (two types); heat pump water heaters; and heat recovery from a heat pump or air conditioner. To account for variations within the MASEC region, information on water heating in Rapid City, Minneapolis, Chicago, Detroit, and Kansas City is presented in detail. Information on geography, major population centers, fuel prices, climate, and state solar incentives is covered. (MCW)

  19. Reducing human exposure to Mycobacterium avium.

    PubMed

    Falkinham, Joseph O

    2013-08-01

    In light of the increasing prevalence of Mycobacterium avium pulmonary disease and the challenges of treating patients with M. avium infection, consideration of measures to reduce exposure is warranted. Because M. avium inhabits water and soil, humans are surrounded by that opportunistic pathogen. Because infection has been linked to the presence of M. avium in household plumbing, increasing hot water temperature, reducing aerosol (mist) exposures in bathrooms and showers, and installing filters that prevent the passage of mycobacteria will likely reduce M. avium exposure. Granular activated carbon (charcoal) filters support the growth of M. avium and should be avoided. When gardening, avoid the inhalation of soil dusts by using a mask or wetting the soil because peat-rich potting soils have high numbers of mycobacteria. PMID:23952861

  20. 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.

  1. 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.

  2. 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.

  3. 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

  4. 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.

  5. Does Formal Employment Reduce Informal Caregiving?

    PubMed

    He, Daifeng; McHenry, Peter

    2016-07-01

    Using the Survey of Income and Program Participation, we examine the impact of formal employment on informal caregiving. We instrument for individual work hours with state unemployment rates. We find that, among women of prime caregiving ages (40-64 years), working 10% more hours per week reduces the probability of providing informal care by about 2 percentage points. The effects are stronger for more time-intensive caregiving and if care recipients are household members. Our results imply that work-promoting policies have the unintended consequence of reducing informal caregiving in an aging society. Copyright © 2015 John Wiley & Sons, Ltd. PMID:26017375

  6. 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.

  7. Reducing the cost of HIV antibody testing.

    PubMed

    Tamashiro, H; Maskill, W; Emmanuel, J; Fauquex, A; Sato, P; Heymann, D

    1993-07-10

    Available tests to detect antibody to human immunodeficiency virus (HIV) have a range of applications, and injudicious selection and inappropriate use can add a significant financial burden to budgets for AIDS programmes in developing countries. There are several ways by which the cost of HIV antibody testing can be reduced; they include use of tests appropriate for existing laboratory capabilities; adoption of cost-effective testing strategies; pooling of serum samples before testing; and ensuring best possible purchase prices. Each approach can significantly reduce the cost of HIV antibody testing alone or in combination, which increases the potential sustainability of antibody testing programmes, even in settings of limited resources. PMID:8100916

  8. 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. PMID:27131698

  9. Method of reducing drag in aerodynamic systems

    NASA Technical Reports Server (NTRS)

    Hrach, Frank J. (Inventor)

    1993-01-01

    In the present method, boundary layer thickening is combined with laminar flow control to reduce drag. An aerodynamic body is accelerated enabling a ram turbine on the body to receive air at velocity V sub 0. The discharge air is directed over an aft portion of the aerodynamic body producing boundary layer thickening. The ram turbine also drives a compressor by applying torque to a shaft connected between the ram turbine and the compressor. The compressor sucks in lower boundary layer air through inlets in the shell of the aircraft producing laminar flow control and reducing drag. The discharge from the compressor is expanded in a nozzle to produce thrust.

  10. Reducing the capacitance of piezoelectric film sensors

    NASA Astrophysics Data System (ADS)

    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/N2, 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.

  11. Reducing admissions with patient group directions.

    PubMed

    Wat, Dennis; Glossage, Elaine; Hampson, Onnor; Sibley, Sarah

    In times of financial restrictions and reform impediments, health services need to invest in resources that provide value for money and reduce hospital admissions. Improving disease management in the community is a primary target for those trying to reduce costs. The second most common cause of emergency admissions to hospital is chronic obstructive pulmonary disease and it has been suggested that more effective treatments and better management of the condition would likely result in an estimated 5% fewer admissions to hospital, saving around pound 15.5m each year. This article discusses how savings could be made by improving care provided in the community. PMID:24834601

  12. 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.

  13. Scientist Researches Way to Reduce Global Warming

    Technology Transfer Automated Retrieval System (TEKTRAN)

    For the last four years, scientists at the USDA, Agricultural Research Service, Northern Plains Agricultural Research Laboratory have been searching for alternative soil and crop management practices to reduce greenhouse gas emissions and increase carbon and nitrogen sequestration. “If we can redu...

  14. Teachers: Recognize Important Steps to Reduce Cheating

    ERIC Educational Resources Information Center

    Supon, Viola

    2008-01-01

    Teachers must walk the steps and live the steps if reducing cheating is going to occur. Teachers begin this process by being cognizant and vigilant relative to administering means of measurement and assigning written work. This process includes skill acquisition in regards to: (1) acknowledging cheating, (2) purposeful planning, (3) electronic…

  15. Microblowing Technique Demonstrated to Reduce Skin Friction

    NASA Technical Reports Server (NTRS)

    Hwang, Danny P.; Biesiadny, Tom J.

    1998-01-01

    One of the most challenging areas of research in aerodynamics is the reduction of skin friction, especially for turbulent flow. Reduced skin friction means less drag. For aircraft, less drag can lead to less fuel burned or to a greater flight range for a fixed amount of fuel. Many techniques and methods have been tried; however, none of them has significantly reduced skin friction in the flight environment. An innovative skin-friction reduction technique, the Microblowing Technique (MBT), was invented in 1993. This is a unique concept in which an extremely small amount of air is blown vertically at a surface through very small holes. It can be used for aircraft or marine vehicles, such as submarines (where water is blown through the holes instead of air). As shown in the figure, the outer layer, which controls vertical flow, is a plate with high-vertical holes. The inner layer, which produces evenly distributed flow, is a low-permeability porous plate. Microblowing reduces the surface roughness and changes the flow velocity profile on the surface, thereby reducing skin friction.

  16. Heat recovery reduces process energy losses

    SciTech Connect

    Anon

    1981-09-01

    After evaluation of process and plant operation losses, a pharmaceutical plant found heat recovery a viable means of reducing energy losses. One of the first applications of air-to-air heat recovery was in a recirculation/dehumidification process. Heat exchangers were used to recover heat from the air used to generate or dry the dehumidification material.

  17. Reducing Radon in Schools: A Team Approach.

    ERIC Educational Resources Information Center

    Ligman, Bryan K.; Fisher, Eugene J.

    This document presents the process of radon diagnostics and mitigation in schools to help educators determine the best way to reduce elevated radon levels found in a school. The guidebook is designed to guide school leaders through the process of measuring radon levels, selecting the best mitigation strategy, and directing the efforts of a…

  18. Reduced No.sub.x combustion method

    DOEpatents

    Delano, Mark A.

    1991-01-01

    A combustion method enabling reduced NO.sub.x formation wherein fuel and oxidant are separately injected into a combustion zone in a defined velocity relation, combustion gases are aspirated into the oxidant stream prior to intermixture with the fuel, and the fuel is maintained free from contact with oxygen until the intermixture.

  19. Reduced-Bandwidth Coding for Mobile Communication

    NASA Technical Reports Server (NTRS)

    Davarian, F.

    1986-01-01

    Fade-resistant mobile systems use power and spectrum efficiently. Transmission system employs tone-calibrated technique (TCT). Residual carrier used in technique to reduce fading-induced effects and coherently demodulate received signal. TCT potentially efficient in use of power and of frequency spectrum. Coding technique, intended for residual-carrier transmission system, alleviates fading and spectrum crowding that hamper mobile communications.

  20. 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…

  1. Coatings to reduce wood preservative leaching.

    PubMed

    Nejad, Mojgan; Cooper, Paul

    2010-08-15

    The efficiency of semitransparent penetrating stains to reduce leaching of wood preservative components was evaluated. Five commercial wood deck finishes were applied to untreated and chromated copper arsenate (CCA), alkaline copper quat (ACQ), and copper azole (CA) treated wood, and leachates were collected and analyzed during 3 years of natural weathering exposure in Toronto, Canada. All stains evaluated effectively reduced the cumulative leaching of all inorganic preservative components by about 60% on average. Although most coatings showed significant film degradation starting around 12 months, the reduced leaching persisted even after 3 years. This suggests that temporary protection of wood with a coating during the early stages of use resulted in long-term reduction in preservative leaching potential. A two-week screening leaching test was able to predict the long-term leaching performance of different coatings reasonably well. Cured coating glass transition temperature (Tg) and liquid coating viscosity were the most important variables affecting a leaching prediction model. To effectively reduce leaching of preservative components from treated wood, coatings should have Tg low enough to withstand stresses caused by freezing in winter and have adequate viscosity to form a barrier film layer on the wood surface. PMID:20704213

  2. Reducing exhaust gas emissions from Citydiesel busses

    NASA Astrophysics Data System (ADS)

    Mikkonen, Seppo

    The effect of fuel composition and exhaust gas aftertreatment on the emissions was measured from truck and bus engines. Possibilities to measure unregulated emissions (aldehydes, polyaromatic hydrocarbons, mutagenicity) were built. A reformulated diesel fuel 'Citydiesel' was developed. Citydiesel was able to reduce emissions compared to standard diesel fuel as follows: particulates by 10 to 30%, nitrogen oxides by 2 to 10%, sulphur dioxide by 97%, polyaromatic hydrocarbons (PAH) over 50%, mutagenicity of the exhaust particulates clearly, odor of the exhaust, and smoke after a cold start. The use of Citydiesel fuel reduces emissions of the existing vehicles immediately which is a remarkable benefit. The very low sulphur content (below 50 ppm) makes it possible to use oxidation. catalytic converters to reduce emissions of diesel vehicles. The new Euro 2 exhaust regulations coming into force during 1996 can be met with a modern diesel engine, Citydiesel fuel, and exhaust gas aftertreatment. Properties of Citydiesel fuel were verified in a three year field test with 140 city buses. Experience was good; e.g., engine oil change interval could be lengthened. Total value of the exhaust was estimated with different fuels and aftertreatment device in order to find out cheap ways to reduce emissions.

  3. 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.

  4. 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.

  5. Reduced Tillage in an Irrigated Potato Rotation

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato production in irrigated regions typically occurs on soils low in organic matter that are highly susceptible to agri-chemical leaching under poor irrigation scheduling, and wind erosion when soils are left bare. Reduced tillage has had limited testing in potato production. The objective of thi...

  6. Method for reducing snap in magnetic amplifiers

    NASA Technical Reports Server (NTRS)

    Fischer, R. L. E.; Word, J. L.

    1968-01-01

    Method of reducing snap in magnetic amplifiers uses a degenerative feedback circuit consisting of a resistor and a separate winding on a magnetic core. The feedback circuit extends amplifier range by allowing it to be used at lower values of output current.

  7. Reducing pharmacy costs through improved utilization.

    PubMed

    Bates, Cinda; Richards, Barton S

    2013-06-01

    Strategies Trinity Regional Health System in Rock Island, III., used to reduce pharmacy expenses included: Leveraging benchmarking information to identify opportunities for cost savings. Implementing change management techniques, bolstered by well-presented and coherent data, to promote acceptance of change. Forming a multidisciplinary team of clinical and financial leaders to address quality, outcomes, and cost issues and collaborate on solutions. PMID:23795386

  8. PRACTICAL PROBLEMS REDUCING RADON IN HOUSES

    EPA Science Inventory

    The paper discusses practical problems encountered during efforts to reduce radon concentrations in houses. The 10 problems identified represent only a few of the many daily problems encountered by diagnosticians and mitigators. Nonetheless, they are some of the current common pr...

  9. Strategies for Reducing Text Book Costs

    ERIC Educational Resources Information Center

    Board of Governors, State University System of Florida, 2008

    2008-01-01

    In recent years, the price of college textbooks has become a growing concern for students and others who care about keeping college costs affordable. As policymakers and higher education systems explore the issue further, there are actions that can be taken immediately on college campuses to reduce the cost of textbooks. This brief presents…

  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. 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…

  12. Reducing Thermal Conduction In Acoustic Levitators

    NASA Technical Reports Server (NTRS)

    Lierke, Ernst G.; Leung, Emily W.; Bhat, Balakrishna T.

    1991-01-01

    Acoustic transducers containing piezoelectric driving elements made more resistant to heat by reduction of effective thermal-conductance cross sections of metal vibration-transmitting rods in them, according to proposal. Used to levitate small objects acoustically for noncontact processing in furnaces. Reductions in cross sections increase amplitudes of transmitted vibrations and reduce loss of heat from furnaces.

  13. Reducing Vandalism by Changing the School Community.

    ERIC Educational Resources Information Center

    Flaherty, Geraldine

    1987-01-01

    One South Bronx (New York) school is untouched by vandalism because the teachers have made a commitment to the school and its students, expressing their concern and approval. The extensive costs of vandalism in other schools could be reduced if teachers were trained to develop positive school climates. (PGD)

  14. 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

  15. Identifying and reducing constraints to potato productivity

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Potato yield in Maine has remained relatively constant for over 50 years, despite increased inputs of pesticides, nutrients, and water. Research is needed to identify and reduce the constraints to potato productivity. We evaluated Status Quo, Soil Conserving, Soil Improving, and Disease Suppressive ...

  16. Reducing Dogmatism among Undergraduate Counselor Trainees.

    ERIC Educational Resources Information Center

    Parkay, Forrest W.

    Previous research has emphasized the significant negative correlation between counselor effectiveness and dogmatism, or closemindedness. To reduce levels of dogmatism in counselor trainees, a program was developed and tested at Southwest Texas State University. The new course, "Guidance to Meet the Needs of Multicultural Students," gave counseling…

  17. Reduced alphabet for protein folding prediction.

    PubMed

    Huang, Jitao T; Wang, Titi; Huang, Shanran R; Li, Xin

    2015-04-01

    What are the key building blocks that would have been needed to construct complex protein folds? This is an important issue for understanding protein folding mechanism and guiding de novo protein design. Twenty naturally occurring amino acids and eight secondary structures consist of a 28-letter alphabet to determine folding kinetics and mechanism. Here we predict folding kinetic rates of proteins from many reduced alphabets. We find that a reduced alphabet of 10 letters achieves good correlation with folding rates, close to the one achieved by full 28-letter alphabet. Many other reduced alphabets are not significantly correlated to folding rates. The finding suggests that not all amino acids and secondary structures are equally important for protein folding. The foldable sequence of a protein could be designed using at least 10 folding units, which can either promote or inhibit protein folding. Reducing alphabet cardinality without losing key folding kinetic information opens the door to potentially faster machine learning and data mining applications in protein structure prediction, sequence alignment and protein design. PMID:25641420

  18. Reduced Redundancy as a Language Testing Tool.

    ERIC Educational Resources Information Center

    Spolsky, Bernard

    Redundancy in language reduces the possiblity of error and permits communication where there is interference in the communicating channel. The relationship between creativity (the basic distinction between language-like behavior and knowing a language) and redundancy has been clearly established. Knowledge of rules is the key factor in creativity…

  19. Perioperative Interventions to Reduce Chronic Postsurgical Pain

    PubMed Central

    Carroll, Ian; Hah, Jennifer; Mackey, Sean; Ottestad, Einar; Kong, Jiang Ti; Lahidji, Sam; Tawfik, Vivianne; Younger, Jarred; Curtin, Catherine

    2016-01-01

    Approximately 10% of patients following a variety of surgeries develop chronic postsurgical pain. Reducing chronic postoperative pain is especially important to reconstructive surgeons because common operations such as breast and limb reconstruction have even higher risk for developing chronic postsurgical pain. Animal studies of posttraumatic nerve injury pain demonstrate that there is a critical time frame before and immediately after nerve injury in which specific interventions can reduce the incidence and intensity of chronic neuropathic pain behaviors–so called “preventative analgesia.” In animal models, perineural local anesthetic, systemic intravenous local anesthetic, perineural clonidine, systemic gabapentin, systemic tricyclic antidepressants, and minocycline have each been shown to reduce pain behaviors days to weeks after treatment. The translation of this work to humans also suggests that brief perioperative interventions may protect patients from developing new chronic postsurgical pain. Recent clinical trial data show that there is an opportunity during the perioperative period to dramatically reduce the incidence and severity of chronic postsurgical pain. The surgeon, working with the anesthesiologist, has the ability to modify both early and chronic postoperative pain by implementing an evidence-based preventative analgesia plan. PMID:23463498

  20. 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.)

  1. Reducing Test Anxiety: A Right Brain Approach.

    ERIC Educational Resources Information Center

    Cohen, Ruth I.

    Methods of helping students reduce test anxiety are discussed, including guided fantasy which leads students to imagine a setting in which they feel competent and relaxed. Catastrophic-anastrophic expectations teach that different expectations create different feelings and make students aware that they are in charge of their own attitudes. Anxiety…

  2. 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…

  3. 76 FR 68295 - Reducing Prescription Drug Shortages

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-11-03

    ....) THE WHITE HOUSE, October 31, 2011. [FR Doc. 2011-28728 Filed 11-2-11; 11:15 am] Billing code 3295-F2-P ... Documents#0;#0; ] Executive Order 13588 of October 31, 2011 Reducing Prescription Drug Shortages By the... hereby ordered as follows: Section 1. Policy. Shortages of pharmaceutical drugs pose a serious...

  4. 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: intense…

  5. Reducing the White-Nonwhite Achievement Gap.

    ERIC Educational Resources Information Center

    Ramey, Madelaine

    It is well documented that there continues to be a gap between white and nonwhite student achievement. A study develops and tests a measure of white-nonwhite achievement gap reduction. The ultimate purpose is to use the measure as the dependent variable in a qualitative study of what works in reducing the gap. The strategy used in addressing this…

  6. 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.

  7. Finding Strategic Solutions to Reduce Truancy

    ERIC Educational Resources Information Center

    Reid, Ken

    2010-01-01

    This article focuses on recent developments to find strategic solutions to the problem of truancy. It considers issues related to defining truancy and why reducing truancy matters before considering what causes truancy. The article concentrates upon seven areas where further work is needed: the role of parents (and carers); early intervention,…

  8. Poultry litter moisture management to reduce ammonia

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ammonia generation in poultry houses results from the natural breakdown of litter (bedding material mixed with deposits of feces, feathers, spilled feed and water). Good management practices can reduce ammonia concentrations in poultry houses. This factsheet relates findings from a recent publicat...

  9. 40 CFR 1500.4 - Reducing paperwork.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Reducing paperwork. 1500.4 Section 1500.4 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.4... effect on the human environment and which are therefore exempt from requirements to prepare...

  10. 40 CFR 1500.4 - Reducing paperwork.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Reducing paperwork. 1500.4 Section 1500.4 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.4... effect on the human environment and which are therefore exempt from requirements to prepare...

  11. 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.

  12. Cost-reducing multipurpose microfilm card

    NASA Technical Reports Server (NTRS)

    Smith, A. V.

    1970-01-01

    Microfilm-aperture card is printed in the same format on both sides which enables the use of one card for mounting films that are ''right reading'' on both the base side and the emulsion side. This reduces the number of microfilm-card formats.

  13. 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…

  14. Heat Pipes Reduce Engine-Exhaust Emissions

    NASA Technical Reports Server (NTRS)

    Schultz, D. F.

    1986-01-01

    Increased fuel vaporization raises engine efficiency. Heat-pipe technology increased efficiency of heat transfer beyond that obtained by metallic conduction. Resulted in both improved engine operation and reduction in fuel consumption. Raw material conservation through reduced dependence on strategic materials also benefit from this type of heat-pipe technology. Applications result in improved engine performance and cleaner environment.

  15. Attributional Retraining: Reducing the Likelihood of Failure

    ERIC Educational Resources Information Center

    Haynes Stewart, Tara L.; Clifton, Rodney A.; Daniels, Lia M.; Perry, Raymond P.; Chipperfield, Judith G.; Ruthig, Joelle C.

    2011-01-01

    Failing a course is an acutely negative event for first-year university students, and a major contributor to high attrition rates at North American universities. Despite its prevalence, course failure receives relatively little research attention. What can be done to reduce course failure and help first-year students remain in university? This…

  16. Sliding, Insulating Window Panel Reduces Heat Loss.

    ERIC Educational Resources Information Center

    School Business Affairs, 1984

    1984-01-01

    A new sliding insulated panel reduces window heat loss up to 86 percent, and infiltration 60-90 percent, paying for itself in 3-9 years. This article discusses the panel's use and testing in the upper Midwest, reporting both technical characteristics and users' reactions. (MCG)

  17. 40 CFR 1500.4 - Reducing paperwork.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Reducing paperwork. 1500.4 Section 1500.4 Protection of Environment COUNCIL ON ENVIRONMENTAL QUALITY PURPOSE, POLICY, AND MANDATE § 1500.4... effect on the human environment and which are therefore exempt from requirements to prepare...

  18. Chemicals Reduce Need To Mow Grass

    NASA Technical Reports Server (NTRS)

    Humphrys, Brooks; Farley, Max; Gast, Larry J.

    1993-01-01

    Brief report discusses use of herbicides Roundup(R), Campaign(R), and Oust(R) to retard growth of Argentine bahia grass. Herbicide applied by use of spraying apparatus pulled by tractor. "Chemical mowing" keeps grass at "freshly mowed" height with less mechanical mowing. Applied to grass on shoulders of roads, reducing time spent on mowing.

  19. Reducing Children's Littering on a Nature Trail

    ERIC Educational Resources Information Center

    LaHart, David E.; Bailey, Jon S.

    1975-01-01

    This study compared incentives and educational methods to motivate children to pick up litter and to prevent littering. Incentives did aid in getting litter picked up. One-sentence anti-litter statements, educational materials, and lectures reduced littering, but incentives did not. (MR)

  20. 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…

  1. 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.

  2. 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.

  3. 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.

  4. Reducing Abstraction When Learning Graph Theory

    ERIC Educational Resources Information Center

    Hazzan, Orit; Hadar, Irit

    2005-01-01

    This article presents research on students' understanding of basic concepts in Graph Theory. Students' understanding is analyzed through the lens of the theoretical framework of reducing abstraction (Hazzan, 1999). As it turns out, in spite of the relative simplicity of the concepts that are introduced in the introductory part of a traditional…

  5. UVC LIGHT TREATMENT REDUCES DECAY OF BLUEBERRIES

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Ultraviolet light treatment has been used successfully to reduce postharvest fungal decay in tomatoes, strawberries, peaches, and citrus, presumably through elevated spore death and/or increased phytoalexins. The purpose of this experiment was to determine the effectiveness of UV-C light as a posth...

  6. Sexual Harassment at Camp: Reducing Liability.

    ERIC Educational Resources Information Center

    Oakleaf, Linda; Grube, Angela Johnson

    2003-01-01

    Employers are responsible for sexual harassment perpetrated by a supervisor. Camps may be responsible for sexual harassment between campers. Steps to reduce liability include providing multiple channels for reporting sexual harassment; having written policies prohibiting sexual harassment and procedures for reporting it; posting these policies and…

  7. 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.

  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. 76 FR 75798 - Reducing Regulatory Burden

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-12-05

    ...; ] DEPARTMENT OF ENERGY 5 CFR Chapter XXIII 10 CFR Chapters II, III, X Reducing Regulatory Burden AGENCY: Office... its implementation of Executive Order 13563, ``Improving Regulation and Regulatory Review,'' issued by... General Counsel for Legislation, Regulation, and Energy Efficiency, U.S. Department of Energy, Office...

  10. Device and Method for Reducing Aircraft Noise

    NASA Technical Reports Server (NTRS)

    Streett, Craig L. (Inventor); Lin, John C. (Inventor)

    2002-01-01

    A noise abatement device that is positioned adjacent to a body. The noise abatement device generally includes tabs or cavities which thicken the shear layer created by fluid flow over, around, or near the body, by creating horseshoe-shaped vortices; this thickening of the shear layer reduces the strength of fluctuations in the flow which produce noise.

  11. 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…

  12. Reducing Infant Mortality. KIDS COUNT Indicator Brief

    ERIC Educational Resources Information Center

    Shore, Rima; Shore, Barbara

    2009-01-01

    Despite the wide range of expertise that has been brought to bear on reducing infant mortality across the nation, the first year of life remains a time of considerable risk for many babies. Although the U.S. spends more on health care than any other country, its infant mortality rate remains higher than that of most other industrialized nations.…

  13. 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…

  14. Reducing Mathematics Anxiety with Computer Assisted Instruction.

    ERIC Educational Resources Information Center

    Harris, Albert L.; Harris, Jacqueline M.

    1987-01-01

    Student, teacher, and teaching causes of mathematics anxiety are discussed. Computer-assisted instruction can reduce mathematics anxieties due to lack of confidence, negative attitudes, teacher bias, authoritarian teaching, lack of variety, lack of relationship with the real world, emphasis on memorization or on speed, or computer phobia. (MNS)

  15. On reduced density matrices for disjoint subsystems

    NASA Astrophysics Data System (ADS)

    Iglói, F.; Peschel, I.

    2010-02-01

    We show that spin and fermion representations for solvable quantum chains lead in general to different reduced density matrices if the subsystem is not singly connected. We study the effect for two sites in XX and XY chains as well as for sublattices in XX and transverse Ising chains.

  16. The Three Rs: Reduce, Reuse, Recycle.

    ERIC Educational Resources Information Center

    Science Activities, 1991

    1991-01-01

    A student hand-out for a recycling unit defines the terms reduce, recycle, and reuse as they relate to solid waste management. Presents the characteristics of recyclable items such as yard wastes, metals, glass, and paper. Lists organizations through which more information about recycling can be obtained. (MCO)

  17. 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.

  18. Understanding Uranium Behavior in a Reduced Aquifer

    NASA Astrophysics Data System (ADS)

    Janot, N.; Lezama-Pacheco, J. S.; Williams, K. H.; Bernier-Latmani, R.; Long, P. E.; Davis, J. A.; Fox, P. M.; Yang, L.; Giammar, D.; Cerrato, J. M.; Bargar, J.

    2012-12-01

    Uranium contamination of groundwater is a concern at several US Department of Energy sites, such Old Rifle, CO. Uranium transport in the environment is mainly controlled by its oxidation state, since oxidized U(VI) is relatively mobile, whereas U(IV) is relatively insoluble. Bio-remediation of contaminated aquifers aims at immobilizing uranium in a reduced form. Previous laboratory and field studies have shown that adding electron donor (lactate, acetate, ethanol) to groundwater stimulates the activity of metal- and sulfate-reducing bacteria, which promotes U(VI) reduction in contaminated aquifers. However, obtaining information on chemical and physical forms of U, Fe and S species for sediments biostimulated in the field, as well as kinetic parameters such as U(VI) reduction rate, is challenging due to the low concentration of uranium in the aquifers (typically < 10 ppm) and the expense of collecting large number of cores. An in-situ technique has been developed for studying uranium, iron and sulfur reduction dynamics during such bioremediation episodes. This technique uses in-well columns to obtain direct access to chemical and physical forms of U(IV) produced in the aquifer, evolving microbial communities, and trace and major ion groundwater constituents. While several studies have explored bioreduction of uranium under sulfate-reducing conditions, less attention has been paid to the initial iron-reducing phase, noted as being of particular importance to uranium removal. The aim of this work was to assess the formation of U(IV) during the early stages of a bio-remediation experiment at the Old Rifle site, CO, from early iron-reducing conditions to the transition to sulfate-reducing conditions. Several in-well chromatographic columns packed with sediment were deployed and were sampled at different days after the start of bio-reduction. X-ray absorption spectroscopy and X-ray microscopy were used to obtain information on Fe, S and U speciation and distribution

  19. Glucocorticoids reduce phobic fear in humans

    PubMed Central

    Soravia, Leila M.; Heinrichs, Markus; Aerni, Amanda; Maroni, Caroline; Schelling, Gustav; Ehlert, Ulrike; Roozendaal, Benno; de Quervain, Dominique J.-F.

    2006-01-01

    Phobias are characterized by excessive fear, cued by the presence or anticipation of a fearful situation. Whereas it is well established that glucocorticoids are released in fearful situations, it is not known whether these hormones, in turn, modulate perceived fear. As extensive evidence indicates that elevated glucocorticoid levels impair the retrieval of emotionally arousing information, they might also inhibit retrieval of fear memory associated with phobia and, thereby, reduce phobic fear. Here, we investigated whether acutely administrated glucocorticoids reduced phobic fear in two double-blind, placebo-controlled studies in 40 subjects with social phobia and 20 subjects with spider phobia. In the social phobia study, cortisone (25 mg) administered orally 1 h before a socio-evaluative stressor significantly reduced self-reported fear during the anticipation, exposure, and recovery phase of the stressor. Moreover, the stress-induced release of cortisol in placebo-treated subjects correlated negatively with fear ratings, suggesting that endogenously released cortisol in the context of a phobic situation buffers fear symptoms. In the spider phobia study, repeated oral administration of cortisol (10 mg), but not placebo, 1 h before exposure to a spider photograph induced a progressive reduction of stimulus-induced fear. This effect was maintained when subjects were exposed to the stimulus again 2 days after the last cortisol administration, suggesting that cortisol may also have facilitated the extinction of phobic fear. Cortisol treatment did not reduce general, phobia-unrelated anxiety. In conclusion, the present findings in two distinct types of phobias indicate that glucocorticoid administration reduces phobic fear. PMID:16567641

  20. Human Performance in Simulated Reduced Gravity Environments

    NASA Technical Reports Server (NTRS)

    Cowley, Matthew; Harvill, Lauren; Rajulu, Sudhakar

    2014-01-01

    NASA is currently designing a new space suit capable of working in deep space and on Mars. Designing a suit is very difficult and often requires trade-offs between performance, cost, mass, and system complexity. Our current understanding of human performance in reduced gravity in a planetary environment (the moon or Mars) is limited to lunar observations, studies from the Apollo program, and recent suit tests conducted at JSC using reduced gravity simulators. This study will look at our most recent reduced gravity simulations performed on the new Active Response Gravity Offload System (ARGOS) compared to the C-9 reduced gravity plane. Methods: Subjects ambulated in reduced gravity analogs to obtain a baseline for human performance. Subjects were tested in lunar gravity (1.6 m/sq s) and Earth gravity (9.8 m/sq s) in shirt-sleeves. Subjects ambulated over ground at prescribed speeds on the ARGOS, but ambulated at a self-selected speed on the C-9 due to time limitations. Subjects on the ARGOS were given over 3 minutes to acclimate to the different conditions before data was collected. Nine healthy subjects were tested in the ARGOS (6 males, 3 females, 79.5 +/- 15.7 kg), while six subjects were tested on the C-9 (6 males, 78.8 +/- 11.2 kg). Data was collected with an optical motion capture system (Vicon, Oxford, UK) and was analyzed using customized analysis scripts in BodyBuilder (Vicon, Oxford, UK) and MATLAB (MathWorks, Natick, MA, USA). Results: In all offloaded conditions, variation between subjects increased compared to 1-g. Kinematics in the ARGOS at lunar gravity resembled earth gravity ambulation more closely than the C-9 ambulation. Toe-off occurred 10% earlier in both reduced gravity environments compared to earth gravity, shortening the stance phase. Likewise, ankle, knee, and hip angles remained consistently flexed and had reduced peaks compared to earth gravity. Ground reaction forces in lunar gravity (normalized to Earth body weight) were 0.4 +/- 0.2 on