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Sample records for bystander chinese hamster

  1. Low doses of alpha particles do not induce sister chromatid exchanges in bystander Chinese hamster cells defective in homologous recombination

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    Nagasawa, H; Wilson, P F; Chen, D J; Thompson, L H; Bedford, J S; Little, J B

    2007-10-26

    We reported previously that the homologous recombinational repair (HRR)-deficient Chinese hamster mutant cell line irs3 (deficient in the Rad51 paralog Rad51C) showed only a 50% spontaneous frequency of sister chromatid exchange (SCE) as compared to parental wild-type V79 cells. Furthermore, when irradiated with very low doses of alpha particles, SCEs were not induced in irs3 cells, as compared to a prominent bystander effect observed in V79 cells (Nagasawa et al., Radiat. Res. 164, 141-147, 2005). In the present study, we examined additional Chinese hamster cell lines deficient in the Rad51 paralogs Rad51C, Rad51D, Xrcc2, and Xrcc3 as well as another essential HRR protein, Brca2. Spontaneous SCE frequencies in non-irradiated wild-type cell lines CHO, AA8 and V79 were 0.33 SCE/chromosome, whereas two Rad51C-deficient cell lines showed only 0.16 SCE/chromosome. Spontaneous SCE frequencies in cell lines defective in Rad51D, Xrcc2, Xrcc3, and Brca2 ranged from 0.23-0.33 SCE/chromosome, 0-30% lower than wild-type cells. SCEs were induced significantly 20-50% above spontaneous levels in wild-type cells exposed to a mean dose of 1.3 mGy of alpha particles (<1% of nuclei traversed by an alpha particle). However, induction of SCEs above spontaneous levels was minimal or absent after {alpha}-particle irradiation in all of the HRR-deficient cell lines. These data suggest that Brca2 and the Rad51 paralogs contribute to DNA damage repair processes induced in bystander cells (presumably oxidative damage repair in S-phase cells) following irradiation with very low doses of alpha particles.

  2. Proteomic Analysis of Chinese Hamster Ovary Cells

    DEFF Research Database (Denmark)

    Baycin-Hizal, Deniz; Tabb, David L.; Chaerkady, Raghothama;

    2012-01-01

    To complement the recent genomic sequencing of Chinese hamster ovary (CHO) cells, proteomic analysis was performed on CHO cells including the cellular proteome, secretome, and glycoproteome using tandem mass spectrometry (MS/MS) of multiple fractions obtained from gel electrophoresis, multidimens......To complement the recent genomic sequencing of Chinese hamster ovary (CHO) cells, proteomic analysis was performed on CHO cells including the cellular proteome, secretome, and glycoproteome using tandem mass spectrometry (MS/MS) of multiple fractions obtained from gel electrophoresis...

  3. Methods for modeling chinese hamster ovary (cho) cell metabolism

    DEFF Research Database (Denmark)

    2015-01-01

    Embodiments of the present invention generally relate to the computational analysis and characterization biological networks at the cellular level in Chinese Hamster Ovary (CHO) cells. Based on computational methods utilizing a hamster reference genome, the invention provides methods for identify......Embodiments of the present invention generally relate to the computational analysis and characterization biological networks at the cellular level in Chinese Hamster Ovary (CHO) cells. Based on computational methods utilizing a hamster reference genome, the invention provides methods...

  4. Bystander intervention and fear of crime: evidence from two Chinese communities.

    Science.gov (United States)

    Zhong, Lena Y

    2010-04-01

    From the perspective of prosocial behavior, bystander intervention is conditioned by situational factors; from an informal social control perspective, bystander intervention has been demonstrated to be associated with level of crime and violence at the community level. By drawing on findings in two contrasting communities within a Chinese city, this study investigates the effects of fear of crime and type of community on bystander intervention. It shows that fear of crime and type of community have robust and consistent effects on bystander intervention, controlling for demographic characteristics including sex, age, and education. The implications of the findings are discussed in terms of bystander intervention as both prosocial behavior and informal social control. The findings also question the usefulness of simply casting bystander nonintervention as corrupted morality in China.

  5. Proteomic Analysis of Chinese Hamster Ovary Cells

    Science.gov (United States)

    Baycin-Hizal, Deniz; Tabb, David L.; Chaerkady, Raghothama; Chen, Lily; Lewis, Nathan E.; Nagarajan, Harish; Sarkaria, Vishaldeep; Kumar, Amit; Wolozny, Daniel; Colao, Joe; Jacobson, Elena; Tian, Yuan; O'Meally, Robert N.; Krag, Sharon S.; Cole, Robert N.; Palsson, Bernhard O.; Zhang, Hui; Betenbaugh, Michael

    2013-01-01

    In order to complement the recent genomic sequencing of Chinese hamster ovary (CHO) cells, proteomic analysis was performed on CHO including the cellular proteome, secretome, and glycoproteome using tandem mass spectrometry (MS/MS) of multiple fractions obtained from gel electrophoresis, multi-dimensional liquid chromatography, and solid phase extraction of glycopeptides (SPEG). From the 120 different mass spectrometry analyses generating 682,097 MS/MS spectra, 93,548 unique peptide sequences were identified with at most a 0.02 false discovery rate (FDR). A total of 6164 grouped proteins were identified from both glycoproteome and proteome analysis, representing an 8-fold increase in the number of proteins currently identified in the CHO proteome. Furthermore, this is the first proteomic study done using CHO genome exclusively which provides for more accurate identification of proteins. From this analysis, the CHO codon frequency was determined and found to be distinct from humans, which will facilitate expression of human proteins in CHO cells. Analysis of the combined proteomic and mRNA data sets indicated the enrichment of a number of pathways including protein processing and apoptosis but depletion of proteins involved in steroid hormone and glycosphingolipid metabolism. 504 of the detected proteins included N-acetylation modifications and 1292 different proteins were observed to be N-glycosylated. This first large-scale proteomic analysis will enhance the knowledge base about CHO capabilities for recombinant expression and provide information useful in cell engineering efforts aimed at modifying CHO cellular functions. PMID:22971049

  6. Hamster

    NARCIS (Netherlands)

    Muskens, G.J.D.M.; Haye, la M.J.J.

    2016-01-01

    The common hamster occurs locally in the central and Southern part of Limburg. Its habitat is limited to loess and loam soils, which it constructs underground burrows. Changes in Agricultural land use sparked a steady decline from the 1970s onwards, By the end of the 1990s, the common hamster had al

  7. Mitotic spindle proteomics in Chinese hamster ovary cells.

    Directory of Open Access Journals (Sweden)

    Mary Kate Bonner

    Full Text Available Mitosis is a fundamental process in the development of all organisms. The mitotic spindle guides the cell through mitosis as it mediates the segregation of chromosomes, the orientation of the cleavage furrow, and the progression of cell division. Birth defects and tissue-specific cancers often result from abnormalities in mitotic events. Here, we report a proteomic study of the mitotic spindle from Chinese Hamster Ovary (CHO cells. Four different isolations of metaphase spindles were subjected to Multi-dimensional Protein Identification Technology (MudPIT analysis and tandem mass spectrometry. We identified 1155 proteins and used Gene Ontology (GO analysis to categorize proteins into cellular component groups. We then compared our data to the previously published CHO midbody proteome and identified proteins that are unique to the CHO spindle. Our data represent the first mitotic spindle proteome in CHO cells, which augments the list of mitotic spindle components from mammalian cells.

  8. Genomic organization and expression of immunoglobulin genes in the Chinese hamster (Cricetulus griseus).

    Science.gov (United States)

    Qin, T; Zhu, H; Wang, D; Hao, H; Du, W

    2015-01-01

    In science, the hamsters are widely used as a model for studying the human diseases because they display many features like humans. The utility of the Chinese hamster as a biology model can be further enhanced by further characterization of the genes encoding components of the immune system. Here, we report the genomic organization and expression of the Chinese hamster immunoglobulin heavy and light chain genes. The Chinese hamster IgH locus contains 268 VH segments (132 potentially functional genes, 12 ORFs and 124 pseudogenes), 4 DH segments, 6 JH segments, four constant region genes (μ, γ, ε and α) and one reverse δ remnant fragment. The Igκ locus contains only a single Cκ gene, 4 Jκ segments and 48 Vκ segments (15 potentially functional genes and 33 pseudogenes), whereas the Igλ locus contains 4 Cλ genes, but only Cλ 3 and Cλ 4 each preceded by a Jλ gene segment. A total of 49 Vλ segments (39 potentially functional genes, 3 ORFs and 7 pseudogenes) were identified. Analysis of junctions of the recombined V(D)J transcripts reveals complex diversity in both expressed H and κ sequences, but the microhomology-directed VJ recombination obviously results in very limited diversity in the Chinese hamster λ gene despite more potential germline-encoded combinatorial diversity. This is the first study to make a comprehensive analysis of the Ig genes in the Chinese hamster, which provides insights into the Ig genes in placental mammals.

  9. Propranolol induced chromosomal aberrations in Chinese hamster ovary cell line

    Directory of Open Access Journals (Sweden)

    Mozhgan Sedigh-Ardekani

    2013-03-01

    Full Text Available Propranolol (PL, a non-selective beta-blocker, is a cardiovascular drug widely used to treat hypertension. The present study was concerned with assessing the cytogenetic effects of this drug on Chinese hamster ovary (CHO cell line. MTT assay was then carried out to determine the cytotoxicity index (IC50 of the drug. The IC50 value of PL was 0.43±0.02 mM. To investigate the clastogenic effects of the drug, chromatid and chromosome breaks and polyploidy in metaphases were analyzed. CHO cells were exposed to different concentrations of the drug (0.1, 0.2, 0.3, 0.4 mM for 24 hours. Considering that PL has liver metabolism, experiments were carried out in the presence and absence of the metabolic activation system (S9 mix. Mitomycin-C and sodium arsenite were used as positive controls. It was observed that in cells treated with different PL concentrations as 0.1, 0.2 and 0.3 mM, the frequency of chromatid and chromosome breaks as well as polyploidy increased when compared with untreated CHO cells. The addition of S9 mix significantly decreased the chromatid breaks, chromosome breaks and polyploidy compared to the treatment of PL alone. It is concluded that, PL causes chromatid and chromosome aberrations in CHO cell line and the metabolic activation system (S9 mix, playing an important role in drug cytotoxicity reduction.

  10. Transcriptome dynamics of transgene amplification in Chinese hamster ovary cells.

    Science.gov (United States)

    Vishwanathan, Nandita; Le, Huong; Jacob, Nitya M; Tsao, Yung-Shyeng; Ng, Sze-Wai; Loo, Bernard; Liu, Zhong; Kantardjieff, Anne; Hu, Wei-Shou

    2014-03-01

    Dihydrofolate reductase (DHFR) system is used to amplify the product gene to multiple copies in Chinese Hamster Ovary (CHO) cells for generating cell lines which produce the recombinant protein at high levels. The physiological changes accompanying the transformation of the non-protein secreting host cells to a high producing cell line is not well characterized. We performed transcriptome analysis on CHO cells undergoing the selection and amplification processes. A host CHO cell line was transfected with a vector containing genes encoding the mouse DHFR (mDHFR) and a recombinant human IgG (hIgG). Clones were isolated following selection and subcloned following amplification. Control cells were transfected with a control plasmid which did not have the hIgG genes. Although methotrexate (MTX) amplification increased the transcript level of the mDHFR gene significantly, its effect on both hIgG heavy and light chain genes was more modest. The subclones appeared to retain the transcriptome signatures of their parental clones, however, their productivity varied among those derived from the same clone. The transcript levels of hIgG transgenes of all subclones fall in a narrower range than the product titer, alluding to the role of many functional attributes, other than transgene transcript, on productivity. We cross examined functional class enrichment during selection and amplification as well as between high and low producers and discerned common features among them. We hypothesize that the role of amplification is not merely increasing transcript levels, but also enriching survivors which have developed the cellular machinery for secreting proteins, leading to an increased frequency of isolating high-producing clones. We put forward the possibility of assembling a hyper-productivity gene set through comparative transcriptome analysis of a wide range of samples.

  11. Existence of an Endogenous Glutamate and Aspartate Transporter in Chinese Hamster Ovary Cells

    Institute of Scientific and Technical Information of China (English)

    Xunhe JI; Yuhua JIN; Yaoyue CHEN; Chongyong LI; Lihe GUO

    2007-01-01

    Chinese hamster ovary cells show endogenous high-affinity Na+-dependent glutamate transport activity. This transport activity is kinetically similar to a glutamate transporter family strategically expressed in the central nervous system and is pharmacologically unlike glutamate transporter-1 or excitatory amino acid carrier 1. The cDNA of a glutamate/aspartate transporter (GLAST)-like transporter was obtained and analyzed. The deduced amino acid sequence showed high similarity to human, mouse, and rat GLAST. We concluded that a GLAST-like glutamate transporter exists in Chinese hamster ovary cells that might confer the endogenous high-affinity Na+-dependent glutamate transport activity evident in these cells.

  12. Genomic landscapes of Chinese hamster ovary cell lines as revealed by the Cricetulus griseus draft genome

    DEFF Research Database (Denmark)

    Lewis, Nathan E; Liu, Xin; Li, Yuxiang;

    2013-01-01

    Chinese hamster ovary (CHO) cells, first isolated in 1957, are the preferred production host for many therapeutic proteins. Although genetic heterogeneity among CHO cell lines has been well documented, a systematic, nucleotide-resolution characterization of their genotypic differences has been st...... of this genetic diversity highlight the value of the hamster genome as the reference upon which CHO cells can be studied and engineered for protein production....... stymied by the lack of a unifying genomic resource for CHO cells. Here we report a 2.4-Gb draft genome sequence of a female Chinese hamster, Cricetulus griseus, harboring 24,044 genes. We also resequenced and analyzed the genomes of six CHO cell lines from the CHO-K1, DG44 and CHO-S lineages...

  13. Genomic landscapes of Chinese hamster ovary cell lines as revealed by the Cricetulus griseus draft genome

    DEFF Research Database (Denmark)

    Lewis, Nathan E; Liu, Xin; Li, Yuxiang;

    2013-01-01

    Chinese hamster ovary (CHO) cells, first isolated in 1957, are the preferred production host for many therapeutic proteins. Although genetic heterogeneity among CHO cell lines has been well documented, a systematic, nucleotide-resolution characterization of their genotypic differences has been...... stymied by the lack of a unifying genomic resource for CHO cells. Here we report a 2.4-Gb draft genome sequence of a female Chinese hamster, Cricetulus griseus, harboring 24,044 genes. We also resequenced and analyzed the genomes of six CHO cell lines from the CHO-K1, DG44 and CHO-S lineages....... This analysis identified hamster genes missing in different CHO cell lines, and detected >3.7 million single-nucleotide polymorphisms (SNPs), 551,240 indels and 7,063 copy number variations. Many mutations are located in genes with functions relevant to bioprocessing, such as apoptosis. The details...

  14. Glycoengineering of Chinese hamster ovary cells for enhanced erythropoietin N-glycan branching and sialylation

    DEFF Research Database (Denmark)

    Yin, Bojiao; Gao, Yuan; Chung, Cheng-yu;

    2015-01-01

    -glycosylation of recombinant erythropoietin (rEPO), a human α2,6-sialyltransferase (ST6Gal1) was expressed in Chinese hamster ovary (CHO-K1) cells. Sialylation increased on both EPO and CHO cellular proteins as observed by SNA lectin analysis, and HPLC profiling revealed that the sialic acid content of total glycans on EPO...

  15. Characterization of Chinese Hamster Ovary Cells Producing Coagulation Factor VIII Using Multi-omics Tools

    DEFF Research Database (Denmark)

    Kaas, Christian Schrøder

    The first public draft of a genome from Chinese hamster ovary (CHO) cells was published in 2011, an entire decade after the first draft of the human genome. This publication of a relevant CHO reference genome, in combination with the fact that the cost for DNA sequencing has dropped more than 10,...

  16. Augmenting Chinese hamster genome assembly by identifying regions of high confidence.

    Science.gov (United States)

    Vishwanathan, Nandita; Bandyopadhyay, Arpan A; Fu, Hsu-Yuan; Sharma, Mohit; Johnson, Kathryn C; Mudge, Joann; Ramaraj, Thiruvarangan; Onsongo, Getiria; Silverstein, Kevin A T; Jacob, Nitya M; Le, Huong; Karypis, George; Hu, Wei-Shou

    2016-09-01

    Chinese hamster Ovary (CHO) cell lines are the dominant industrial workhorses for therapeutic recombinant protein production. The availability of genome sequence of Chinese hamster and CHO cells will spur further genome and RNA sequencing of producing cell lines. However, the mammalian genomes assembled using shot-gun sequencing data still contain regions of uncertain quality due to assembly errors. Identifying high confidence regions in the assembled genome will facilitate its use for cell engineering and genome engineering. We assembled two independent drafts of Chinese hamster genome by de novo assembly from shotgun sequencing reads and by re-scaffolding and gap-filling the draft genome from NCBI for improved scaffold lengths and gap fractions. We then used the two independent assemblies to identify high confidence regions using two different approaches. First, the two independent assemblies were compared at the sequence level to identify their consensus regions as "high confidence regions" which accounts for at least 78 % of the assembled genome. Further, a genome wide comparison of the Chinese hamster scaffolds with mouse chromosomes revealed scaffolds with large blocks of collinearity, which were also compiled as high-quality scaffolds. Genome scale collinearity was complemented with EST based synteny which also revealed conserved gene order compared to mouse. As cell line sequencing becomes more commonly practiced, the approaches reported here are useful for assessing the quality of assembly and potentially facilitate the engineering of cell lines.

  17. Toward genome-scale models of the Chinese hamster ovary cells: incentives, status and perspectives

    DEFF Research Database (Denmark)

    Kaas, Christian Schrøder; Fan, Yuzhou; Weilguny, Dietmar;

    2014-01-01

    Bioprocessing of the important Chinese hamster ovary (CHO) cell lines used for the production of biopharmaceuticals stands at the brink of several redefining events. In 2011, the field entered the genomics era, which has accelerated omics-based phenotyping of the cell lines. In this review we...

  18. Assignment of genes encoding metallothioneins I and II to Chinese hamster chromosomes 3. Evidence for the role of chromosome rearrangement in gene amplification

    Energy Technology Data Exchange (ETDEWEB)

    Stallings, R.L.; Munk, A.C.; Longmire, J.L.; Hildebrand, C.E.; Crawford, B.D.

    1984-12-01

    Cadmium resistant (Cd/sup r/) variants with coordinately amplified metallothionein I and II (MTI and MTII) genes have been derived from both Chinese hamster ovary and near-euploid Chinese hamster cell lines. Cytogenetic analyses of Cd/sup r/ variants consistently revealed breakage and rearrangement involving chromosome 3p. In situ hybridization with Chinese hamster MT-encoding cDNA probe localized amplified MT gene sequences near the translocation breakpoint involving chromosome 3p. These observations suggested that both functionally related, isometallothionein loci are linked on Chinese hamster chromosome 3. Southern blot analyses of DNAs isolated from a panel of Chinese hamster x mouse somatic cell hybrids which segregate hamster chromosomes confirmed that both MTI and MTII are located on chromosome 3. The authors speculate that rearrangement of chromosome 3p could be causally involved with the amplification of MT genes in Cd/sup r/ hamster cell lines. 34 references, 3 figures, 1 table.

  19. Genomic landscapes of Chinese hamster ovary cell lines as revealed by the Cricetulus griseus draft genome.

    Science.gov (United States)

    Lewis, Nathan E; Liu, Xin; Li, Yuxiang; Nagarajan, Harish; Yerganian, George; O'Brien, Edward; Bordbar, Aarash; Roth, Anne M; Rosenbloom, Jeffrey; Bian, Chao; Xie, Min; Chen, Wenbin; Li, Ning; Baycin-Hizal, Deniz; Latif, Haythem; Forster, Jochen; Betenbaugh, Michael J; Famili, Iman; Xu, Xun; Wang, Jun; Palsson, Bernhard O

    2013-08-01

    Chinese hamster ovary (CHO) cells, first isolated in 1957, are the preferred production host for many therapeutic proteins. Although genetic heterogeneity among CHO cell lines has been well documented, a systematic, nucleotide-resolution characterization of their genotypic differences has been stymied by the lack of a unifying genomic resource for CHO cells. Here we report a 2.4-Gb draft genome sequence of a female Chinese hamster, Cricetulus griseus, harboring 24,044 genes. We also resequenced and analyzed the genomes of six CHO cell lines from the CHO-K1, DG44 and CHO-S lineages. This analysis identified hamster genes missing in different CHO cell lines, and detected >3.7 million single-nucleotide polymorphisms (SNPs), 551,240 indels and 7,063 copy number variations. Many mutations are located in genes with functions relevant to bioprocessing, such as apoptosis. The details of this genetic diversity highlight the value of the hamster genome as the reference upon which CHO cells can be studied and engineered for protein production.

  20. Superoxide Mediates the Toxicity of Paraquat for Chinese Hamster Ovary Cells

    Science.gov (United States)

    Bagley, Ann C.; Krall, Judith; Lynch, Robert E.

    1986-05-01

    The roles of superoxide and H2O2 in the cytotoxicity of paraquat were assessed in Chinese hamster ovary cells. Neither catalase nor superoxide dismutase inhibited the loss of ability to form colonies when added to the medium. When introduced into the cells, superoxide dismutase but not catalase inhibited the toxicity of paraquat. That superoxide dismutase acted by its known catalytic action is shown by the loss of inhibition when the enzyme was inactivated by H2O2 before being introduced into the cells. The lack of inhibition by catalase, by dimethyl sulfoxide, and by desferoxamine suggests that the toxicity is not mediated by a reaction between H2O2 and superoxide to engender the hydroxyl radical. Exposure of Chinese hamster ovary cells to paraquat may be a suitable means to determine the effects of superoxide anion in cultured cells and the ways in which cells can resist this toxic action.

  1. Interaction of multidrug-resistant Chinese hamster ovary cells with amphiphiles.

    OpenAIRE

    Loe, D. W.; Sharom, F J

    1993-01-01

    The interaction of membrane-active amphiphiles with a series of MDR Chinese hamster ovary (CHO) cell lines was investigated. Cross-resistance to cationic amphiphiles was observed, which was effectively sensitised by verapamil. MDR cells showed collateral sensitivity to polyoxyethylene amphiphiles (Triton X-100/Nonidet P-40), which reached a maximum at 9-10 ethylene oxide units. Resistant lines were also highly collaterally sensitive (17-fold) to dibutylphthalate. mdrl transfectants showed cro...

  2. Discovery of transcription start sites in the Chinese hamster genome by next-generation RNA sequencing.

    Science.gov (United States)

    Jakobi, Tobias; Brinkrolf, Karina; Tauch, Andreas; Noll, Thomas; Stoye, Jens; Pühler, Alfred; Goesmann, Alexander

    2014-11-20

    Chinese hamster ovary (CHO) cell lines are one of the major production tools for monoclonal antibodies, recombinant proteins, and therapeutics. Although many efforts have significantly improved the availability of sequence information for CHO cells in the last years, forthcoming draft genomes still lack the information depth known from the mouse or human genomes. Many genes annotated for CHO cells and the Chinese hamster reference genome still are in silico predictions, only insufficiently verified by biological experiments. The correct annotation of transcription start sites (TSSs) is of special interest for CHO cells, as these directly define the location of the eukaryotic core promoter. Our study aims to elucidate these largely unexplored regions, trying to shed light on promoter landscapes in the Chinese hamster genome. Based on a 5' enriched dual library RNA sequencing approach 6547 TSSs were identified, of which over 90% were assigned to known genes. These TSSs were used to perform extensive promoter studies using a novel, modular bioinformatics pipeline, incorporating analyses of important regulatory elements of the eukaryotic core promoter on per-gene level and on genomic scale.

  3. Recent progress with the DNA repair mutants of Chinese hamster ovary cells

    Energy Technology Data Exchange (ETDEWEB)

    Thompson, L.H.; Salazar, E.P.; Brookman, K.W.; Collins, C.C.; Stewart, S.A.; Busch, D.B.; Weber, C.A.

    1986-04-02

    Repair deficient mutants of Chinese hamster ovary (CHO) cells are being used to identify human genes that correct the repair defects and to study mechanisms of DNA repair and mutagenesis. Five independent tertiary DNA transformants were obtained from the EM9 mutant. In these clones a human DNA sequence was identified that correlated with the resistance of the cells to CldUrd. After Eco RI digestion, Southern transfer, and hybridization of transformant DNAs with the BLUR-8 Alu family sequence, a common fragment of 25 to 30 kb was present. 37 refs., 4 figs., 3 tabs.

  4. Calculation of response of Chinese hamster cells to ions based on track structure theory

    Institute of Scientific and Technical Information of China (English)

    LiuXiao-Wei; ZhangChun-Xiang

    1997-01-01

    Considering biological cells as single target two-hit detectors,an analytic formula to calculate the response of cells to ions is developed based on track structure theory.In the calculation,the splitting deposition energy between ion kill mode and γ kill mode is not used.The results of calculation are in agreement with the experimental data for response of Chinese hamster cells,whose response to γ rays can be described by the response function of single target two hit detector to ions.

  5. Cell killing and mutation induction on Chinese hamster cells by photoradiations

    Energy Technology Data Exchange (ETDEWEB)

    Lam, C.K.C.

    1982-11-01

    Applying radiation directly on cells, far-uv is more effective than black light, and black light is more effective than white light in inducing proliferative death and in inducing resistance to 6-thioguanine (6-TG), ouabain and diptheria toxin (DT). Gold light has no killing and mutagenic effects on CHO (Chinese hamster ovary) cells. Use of filters showed that a small percentage of shorter wavelengths in the far-uv region is responsible for most of the killing and mutagenic effects in the unfiltered broad spectra of black and white light.

  6. Improved antibody production in Chinese hamster ovary cells by ATF4 overexpression

    OpenAIRE

    Haredy, AM; Nishizawa, A.; Honda, K.; T. Ohya; Ohtake, H; Omasa, T

    2013-01-01

    To improve antibody production in Chinese hamster ovary (CHO) cells, the humanized antibody-producing CHO DP-12-SF cell line was transfected with the gene encoding activating transcription factor 4 (ATF4), a central factor in the unfolded protein response. Overexpression of ATF4 significantly enhanced the production of antibody in the CHO DP-12-SF cell line. The specific IgG production rate of in the ATF4-overexpressing CHO-ATF4-16 cells was approximately 2.4 times that of the parental host c...

  7. The evolution of chromosomal instability in Chinese hamster cells: a changing picture?

    Science.gov (United States)

    Ponnaiya, B.; Limoli, C. L.; Corcoran, J.; Kaplan, M. I.; Hartmann, A.; Morgan, W. F.

    1998-01-01

    PURPOSE: To investigate the kinetics of chromosomal instability induced in clones of Chinese hamster cells following X-irradiation. MATERIALS AND METHODS: X-irradiated clones of GM10115, human-hamster hybrid cells containing a single human chromosome 4 (HC4), have been previously established. These clones were defined as unstable if they contained > or = three subpopulations of cells with unique rearrangements of HC4 as detected by FISH. Stable and unstable clones were analysed by FISH and Giemsa staining at various times post-irradiation. RESULTS: While most of the stable clones continued to show chromosomal stability of HC4 over time, one became marginally unstable at approximately 45 population doublings post-irradiation. Clones exhibiting chromosomal instability had one of several fates. Many of the unstable clones were showed similar levels of instability over time. However, one unstable clone became stable with time in culture, while another became even more unstable over time. Cytogenetic analyses of all clones after Giemsa staining indicated that in some clones the hamster chromosomes were rearranged independent of HC4, demonstrating increased frequencies of chromatid breaks and dicentric chromosomes. The majority of the unstable clones also had higher yields of chromatid gaps. CONCLUSIONS: These data demonstrate the dynamic nature of chromosomal instability as measured by two different cytogenetic assays.

  8. Restriction of human adenovirus replication in Chinese hamster cell lines and their hybrids with human cells.

    Science.gov (United States)

    Radna, R L; Foellmer, B; Feldman, L A; Francke, U; Ozer, H L

    1987-11-01

    We have found that the replication of human adenovirus (Ad2) is restricted in multiple Chinese hamster cell lines including CHO and V79. The major site of restriction involves differential accumulation of late viral proteins as demonstrated by immunofluorescence assay and polyacrylamide gel electrophoresis with and without prior immunoprecipitation. Synthesis of fiber and penton base are markedly reduced, whereas others, such as the 100K polypeptide, are synthesized efficiently. This pattern of restriction is similar to that previously reported for Ad2 infection of several monkey cell lines; however, the restriction is more marked in the Chinese hamster cell lines. The restriction is most likely due to a deficient cellular function since stable cell hybrids between V79 or CHO and human cells are permissive for virus replication. By analysis of a series of hybrids with reduced numbers of human chromosomes, fiber synthesis was correlated with the presence of the short arm of human chromosome 3. More hybrids showed restoration of fiber synthesis than production of progeny virus, suggesting that more than one unlinked function is required for the latter.

  9. Glycosylation analysis of an aggregated antibody produced by Chinese hamster ovary cells in bioreactor culture.

    Science.gov (United States)

    Onitsuka, Masayoshi; Kawaguchi, Akira; Asano, Ryutaro; Kumagai, Izumi; Honda, Kohsuke; Ohtake, Hisao; Omasa, Takeshi

    2014-05-01

    N-Glycosylation of therapeutic antibodies contributes not only to their biological function, but also to their stability and tendency to aggregate. Here, we investigated the impact of the glycosylation status of an aggregated antibody that accumulated during the bioreactor culture of Chinese hamster ovary cells. High-performance liquid chromatography analysis showed that there was no apparent difference in the glycosylation patterns of monomeric, dimeric, and large aggregated forms of the antibody. In contrast, lectin binding assays, which enable the total amounts of specific sugar residues to be detected, showed that both galactose and fucose residues in dimers and large aggregates were reduced to 70-80% of the amount in monomers. These results strongly suggest that the lack of N-linked oligosaccharides, a result of deglycosylation or aglycosylation, occurred in a proportion of the dimeric and large aggregated components. The present study demonstrates that glycosylation heterogeneities are a potential cause of antibody aggregation in cell culture of Chinese hamster ovary cells, and that the lack of N-glycosylation promotes the formation of dimers and finally results in large aggregates.

  10. Bystander deixis

    DEFF Research Database (Denmark)

    Rijkhoff, Jan

    1998-01-01

    Romani and several other languages across the globe. The second part is concerned with the contextual factors that must have a place in a discourse model that wants to be able to handle linguistic manifestations of bystander deixis. Due the fact that Romani has typically been used for in...... have borrowed extensively from the Romani lexicon. It will appear that bystander deixis is a universally attested phenomenon which is not restricted to situations in which speakers wish to communicate without being understood by others....

  11. Improving the secretory capacity of Chinese hamster ovary cells by ectopic expression of effector genes: Lessons learned and future directions

    DEFF Research Database (Denmark)

    Hansen, Henning Gram; Pristovsek, Nusa; Kildegaard, Helene Faustrup;

    2017-01-01

    Chinese hamster ovary (CHO) cells are the preferred cell factory for the production of therapeutic glycoproteins. Although efforts primarily within bioprocess optimization have led to increased product titers of recombinant proteins (r-proteins) expressed in CHO cells, post-transcriptional bottle...

  12. Construction of BAC-based physical map and analysis of chromosome rearrangement in Chinese hamster ovary cell lines.

    Science.gov (United States)

    Cao, Yihua; Kimura, Shuichi; Itoi, Takayuki; Honda, Kohsuke; Ohtake, Hisao; Omasa, Takeshi

    2012-06-01

    Chinese hamster ovary (CHO) cells have frequently been used in biotechnology for many years as a mammalian host cell platform for cloning and expressing genes of interest. A detailed physical chromosomal map of the CHO DG44 cell line was constructed by fluorescence in situ hybridization (FISH) imaging using randomly selected 303 BAC clones as hybridization probes (BAC-FISH). The two longest chromosomes were completely paired chromosomes; other chromosomes were partly deleted or rearranged. The end sequences of 624 BAC clones, including 287 mapped BAC clones, were analyzed and 1,119 informative BAC end sequences were obtained. Among 303 mapped BAC clones, 185 clones were used for BAC-FISH analysis of CHO K1 chromosomes and 94 clones for primary Chinese hamster lung cells. Based on this constructed physical map and end sequences, the chromosome rearrangements between CHO DG44, CHO K1, and primary Chinese hamster cells were investigated. Among 20 CHO chromosomes, eight were conserved without large rearrangement in CHO DG44, CHO K1, and primary Chinese hamster cells. This result suggested that these chromosomes were stable and essential in CHO cells and supposedly conserved in other CHO cell lines.

  13. Onderzoek naar de inductie van chromosoomafwijkingen en "sister- chromatid exchanges" door acrylamide met Chinese hamster cellen in vitro

    NARCIS (Netherlands)

    Knaap; A.G.A.C.; Bergkamp; W.G.M.; Groot; M.G.

    1986-01-01

    Acrylamide bleek een clastogene werking te hebben in een test op chromosoomafwijkingen met Chinese hamster cellen in vitro vanaf 0,1 mg/ml (1,4 mmol/l), zowel in aan- als afwezigheid van een systeem voor metaboliosche activering (S9). Tevens induceerde acrylamide in deze cellen een significante

  14. [Susceptibility of the Chinese hamster (Cricetulus griseus) to parasitic infection (3). Experimental infection with Hymenolepis nana or Trichuris muris to the cortisone treated Chinese hamster].

    Science.gov (United States)

    Kutsumi, H; Miyamoto, K; Inaoka, T

    1989-07-01

    Susceptibility of Chinese hamster (Cricetulus griseus) of Asahikawa Colony (CHA) to Hymenolepis nana or Trichuris muris infection was compared in the feces-egg examination with that of mice as the control animals. Though CHA were resistant to the infection of H. nana, they were found to become susceptible to H. nana by the treatment with cortisone. A half number of CHA was infected with H. nana and the eggs were detected from each animal only in 4 or 6 days in the periods of examination more than 40 days. Mice with or without cortisone treatment were equally susceptible to H. nana infection. In another experiment, CHA with or without cortisone treatment were completely resistant to Trichuris muris infection. Mice, as the control animals, were found to be infected with T. muris in both of cortisone-treated and non-treated groups. Results from the fecal examination, it was confirmed that T. muris were expelled naturally from the animals on the weeks of 11 to 33 after infection.

  15. Cytotoxicity of refractory ceramic fibres to Chinese hamster ovary cells in culture.

    Science.gov (United States)

    Hart, G A; Newman, M M; Bunn, W B; Hesterberg, T W

    1992-07-01

    The toxicity/oncogenicity of refractory ceramic fibres have been tested in chronic inhalation studies in rodents. Because these studies are time consuming and expensive, there is a need to develop and validate short-term models to screen fibres for their toxicological potential. In the present study, the toxic effects of four different compositions of refractory ceramic fibres were determined using Chinese hamster ovary cells grown in culture. These refractory ceramic fibres were the same size-selected fibres that had been used in animal inhalation studies, thus facilitating a direct comparison of findings in the two systems. Chinese hamster ovary cells were treated with refractory ceramic fibres 24 hr after seeding into 60-mm culture dishes in Ham's F12 medium with 10% serum. Inhibition of cell proliferation and colony formation were determined after 3-5 days of fibre exposure. Crocidolite and chrysotile asbestos were used as positive controls. Concentration-dependent inhibition of both cell proliferation and colony formation was observed after treatment with refractory ceramic fibres. The LC(50) for the different refractory ceramic fibres ranged from 10 to 30 mug/cm(2). The LC(50)s for crocidolite and chrysotile were 5 mug/cm(2) and 1 mug/cm(2), respectively. To assess the genotoxic potential of these fibres, fibre-exposed Chinese hamster ovary cell cultures were stained with acridine orange and scored for the incidence of micronuclei and other nuclear abnormalities. The incidence of nuclear abnormalities for refractory ceramic fibres at 20 mug/cm(2) ranged from 20 to 40%. Toxic endpoints of the in vitro studies were compared with those of the chronic animal inhalation studies. The latter included induction of lung fibrosis and pleural and airway tumours. A correlation was observed between the in vitro and in vivo toxicological potencies of the respective four refractory ceramic fibres: the fibres that were most toxic in vitro were also the most toxic in the

  16. Electropermeabilization mediates a stable insertion of glycophorin A with Chinese hamster ovary cell membranes.

    Science.gov (United States)

    el Ouagari, K; Benoist, H; Sixou, S; Teissie, J

    1994-02-01

    Electropulsation allowed us to incorporate glycophorin A, an integral membrane protein, into mammalian nucleated cell membranes (Chinese hamster ovary cells). The induction of stable protein association is effective only when the field intensity is higher than its threshold value, creating membrane permeabilization to small molecules. Under controlled conditions, cell viability was only slightly altered by this treatment. Pulse number and duration controlled both the number of modified cells and incorporated molecules. The phenomena was temperature dependent. An average of 5 x 10(4) molecules/cell was bound. About 80% of cells in the pulsed population were observed to incorporate glycophorin. The protein incorporation was shown to be stable 48 h after electroassociation. Electrically bound proteins were shared between the cells after each division. As enhanced binding is detected if glycophorin is added after the pulses, it is the long-lived alteration of the membrane mediated by the pulses which supports the association.

  17. Cloning and Expression of Luteinizing Hormone Subunits in Chinese Hamster Ovary Cell Line

    Directory of Open Access Journals (Sweden)

    Zeinab Soleimanifar

    2016-10-01

    Full Text Available Background: Luteinizing hormone (LH was secreted by the stimulating cells of the testes and ovaries in the anterior pituitary gland. The application of this hormone is in the treatment of men and women with infertility and amenorrhea respectively.Materials and Methods: In the present study the alpha and beta subunits of human LH gene were cloned into the pEGFP-N1 expression vector and produced the recombinant LH hormone in Chinese hamster ovary (CHO eukaryotic system.Results: Alpha and beta subunits of LH hormone were cloned between NheI and BamHI cut sites of pEGFP_N1 expression plasmid and confirmed by PCR.  Hormone expression was evaluated in CHO cell line by Western blotting using the specific antibody.Conclusion: Alpha and beta subunits of LH hormone were expressed in CHO cell line perfectly.

  18. A Consensus Genome-scale Reconstruction of Chinese Hamster Ovary Cell Metabolism

    DEFF Research Database (Denmark)

    Hefzi, Hooman; Ang, Kok Siong; Hanscho, Michael

    2016-01-01

    in CHO and associated them with >1,700 genes in the Cricetulus griseus genome. The genome-scale metabolic model based on this reconstruction, iCHO1766, and cell-line-specific models for CHO-K1, CHO-S, and CHO-DG44 cells provide the biochemical basis of growth and recombinant protein production......Chinese hamster ovary (CHO) cells dominate biotherapeutic protein production and are widely used in mammalian cell line engineering research. To elucidate metabolic bottlenecks in protein production and to guide cell engineering and bioprocess optimization, we reconstructed the metabolic pathways...... simulations show that the metabolic resources in CHO are more than three times more efficiently utilized for growth or recombinant protein synthesis following targeted efforts to engineer the CHO secretory pathway. This model will further accelerate CHO cell engineering and help optimize bioprocesses....

  19. Effects of antioxidants on V79 Chinese hamster cells treated with ferric nitrilotriacetate.

    Directory of Open Access Journals (Sweden)

    Takehara,Yoshiki

    1990-12-01

    Full Text Available The cytotoxic effects of ferric nitrilotriacetate (Fe-NTA have been considered to be caused by free radicals produced by the drug. The present study was carried out to determine whether or not cytotoxic effects of Fe-NTA on cell growth and lipoperoxide formation of Chinese hamster cells were reduced by antioxidants. Using a spin trapping technique, we found that hydroxyl radical formation in the cells increased in the presence of Fe-NTA. Antioxidants, with the exception of superoxide dismutase, slightly inhibited production of the hydroxyl radical. Mannitol significantly reduced lipoperoxide formation, but other antioxidants did not. However, the growth inhibitory effects of Fe-NTA were not attenuated by these antioxidants. These results indicated that the cytotoxic effects of Fe-NTA may be mostly due to unknown factors other than oxygen free radicals.

  20. The genomic sequence of the Chinese hamster ovary (CHO)-K1 cell line

    DEFF Research Database (Denmark)

    Xu, Xun; Pan, Shengkai; Liu, Xin;

    2011-01-01

    Chinese hamster ovary (CHO)-derived cell lines are the preferred host cells for the production of therapeutic proteins. Here we present a draft genomic sequence of the CHO-K1 ancestral cell line. The assembly comprises 2.45 Gb of genomic sequence, with 24,383 predicted genes. We associate most...... of the assembled scaffolds with 21 chromosomes isolated by microfluidics to identify chromosomal locations of genes. Furthermore, we investigate genes involved in glycosylation, which affect therapeutic protein quality, and viral susceptibility genes, which are relevant to cell engineering and regulatory concerns....... Homologs of most human glycosylation-associated genes are present in the CHO-K1 genome, although 141 of these homologs are not expressed under exponential growth conditions. Many important viral entry genes are also present in the genome but not expressed, which may explain the unusual viral resistance...

  1. Versatile microscale screening platform for improving recombinant protein productivity in Chinese hamster ovary cells

    DEFF Research Database (Denmark)

    Hansen, Henning Gram; Nilsson, Claes Nymand; Lund, Anne Mathilde

    2015-01-01

    of four techniques compatible with 96-well microplates: lipid-based transient transfection, cell cultivation in microplates, cell counting and antibody-independent product titer determination based on split-GFP complementation. We were able to demonstrate growth profiles and volumetric productivity of CHO......Chinese hamster ovary (CHO) cells are widely used as cell factories for the production of biopharmaceuticals. In contrast to the highly optimized production processes for monoclonal antibody (mAb)-based biopharmaceuticals, improving productivity of non-mAb therapeutic glycoproteins is more likely...... cells in 96-half-deepwell microplates comparable with those obtained in shake flasks. In addition, we demonstrate that split-GFP complementation can be used to accurately measure relative titers of therapeutic glycoproteins. Using this platform, we were able to detect target gene-specific increase...

  2. A Study on Antitoxic Role of Vesicular Monoamine Transporter 2 in Transgenic Chinese Hamster Overy Cells

    Institute of Scientific and Technical Information of China (English)

    叶民; 丁新生; 董海蓉; 仇镇宁; 管晓虹

    2003-01-01

    Objective:To study the antitoxic role of vesicular monoamine transporter 2 (VMAT2) in transpgenic Chinese Hamster ovary(CHO) cell.Methods:With the technology of transgene from PC12 to CHO,MTT reduction assay was used to detect MPP+ toxic effect on wild type CHO(wtCHO) and transgenic CHO.Meanwhile,the role of reserpine was also observed in MPP+ toxic effects.Results:The sensitivity of transgenic CHO to MPP+ was much less than that of wtCHO with 0.5 mmol/L MPP+.Transgenic CHO had the same sensitivity as wtCHO if rotenone was given.WtCHO,by given reserpine alone,didn''''''''t change its sensitivity to MPP+.Conclusions:VMAT2 has protective effect on transgenic CHO by transporting MPP+ to vesicles.

  3. Enhanced sialylation of recombinant erythropoietin in genetically engineered Chinese-hamster ovary cells.

    Science.gov (United States)

    Jeong, Yeon Tae; Choi, One; Son, Young Dok; Park, Seung Yeol; Kim, Jung Hoe

    2009-04-01

    Sialic acid, the terminal sugar in N-linked complex glycans, is usually found in glycoproteins and plays a major role in determining the circulatory lifespan of glycoproteins. In the present study we attempted to enhance the sialylation of recombinant EPO (erythropoietin) in CHO (Chinese-hamster ovary) cells. To enhance EPO sialylation, we introduced human alpha2,3-ST (alpha2,3-sialyltransferase) and CMP-SAS (CMP-sialic acid synthase) into recombinant human EPO-producing CHO cells. The sialylation of EPO was increased by the expression of alpha2,3-ST alone. Although the co-expression of alpha2,3-ST and CMP-SAS did not further increase sialylation, an increase in the intracellular pool of CMP-sialic acid was noted. On the basis of these observations, it was postulated that the transport capacity of CMP-sialic acid into the Golgi lumen was limited, thereby causing the reduced availability of CMP-sialic acid substrate for sialylation. Therefore, we co-expressed human alpha2,3-ST and CMP-SAS, as well as overexpress Chinese hamster CMP-sialic acid transporter (CMP-SAT) in CHO cells, which produced recombinant human EPO. When alpha2,3-ST, CMP-SAS, and CMP-SAT were overexpressed in CHO cells, there was a corresponding increase in sialylation compared with the co-expression of alpha2,3-ST and CMP-SAS. The present study provides a useful strategy for enhancing the sialylation of therapeutic glycoproteins produced in CHO cells.

  4. Inhaled ozone as a mutagen. II - Effect on the frequency of chromosome aberrations observed in irradiated Chinese hamsters.

    Science.gov (United States)

    Zelac, R. E.; Cromroy, H. L.; Bolch, W. E., Jr.; Dunavant, B. G.; Bevis, H. A.

    1971-01-01

    Exposure-adjusted break frequencies for chromosome aberrations produced in Chinese hamster circulating blood lymphocytes were the quantitative indicator of damage from 5 hrs of exposure to X-radiation and/or to ozone. Radiation produced 5.51 x 0.0001 breaks/cell rad for cells withdrawn 2 weeks after exposure, a reasonable value when compared with data from in vivo exposure of human lymphocytes and Chinese hamster bone marrow cells. Animals exposed to the two agents simultaneously exhibited more than 70% of the total breaks anticipated assuming the expected equal contributions to be additive. Extending to humans, at presently permitted levels, exposure to ozone would be much more detrimental than exposure to radiati*n.

  5. Host range restriction of vaccinia virus in Chinese hamster ovary cells: relationship to shutoff of protein synthesis.

    Science.gov (United States)

    Drillien, R; Spehner, D; Kirn, A

    1978-12-01

    Chinese hamster ovary cells were found to be nonpermissive for vaccinia virus. Although early virus-induced events occurred in these cells (RNA and polypeptide synthesis), subsequent events appeared to be prevented by a very rapid and nonselective shutoff of protein synthesis. Within less than 2 h after infection, both host and viral protein syntheses were arrested. At low multiplicities of infection, inhibition of RNA synthesis with cordycepin resulted in failure of the virus to block protein synthesis. Moreover, infection of the cells in the presence of cycloheximide prevented the immediate onset of shutoff after reversal of cycloheximide. Inactivation of virus particles by UV irradiation also impaired the capacity of the virus to inhibit protein synthesis. These results suggested that an early vaccinia virus-coded product was implicated in the shutoff of protein synthesis. Either the nonpermissive Chinese hamster ovary cells were more sensitive to this inhibition than permissive cells, or a regulatory control of the vaccinia shutoff function was defective.

  6. Chinese hamster ovary cell mutants with multiple glycosylation defects for production of glycoproteins with minimal carbohydrate heterogeneity.

    OpenAIRE

    Stanley, P.

    1989-01-01

    The production of glycoproteins with carbohydrates of defined structure and minimal heterogeneity is important for functional studies of mammalian carbohydrates. To facilitate such studies, several Chinese hamster ovary mutants that carry between two and four glycosylation mutations were developed. All of the lines grew readily in culture despite the drastic simplification of their surface carbohydrates. Therefore, both endogenous glycoproteins and those introduced by transfection can be obta...

  7. Fucan inhibits Chinese hamster ovary cell (CHO) adhesion to fibronectin by binding to the extracellular matrix.

    Science.gov (United States)

    Rocha, Hugo A; Franco, Célia R; Trindade, Edvaldo S; Veiga, Silvio S; Leite, Edda L; Nader, Helena B; Dietrich, Carl P

    2005-07-01

    In recent years, sulfated fucans have emerged as an important class of natural biopolymers. In this study, the anti-adhesive activity of a fucan from the brown seaweed Spatoglossum schröederi was analyzed using tumorigenic cells: wild-type Chinese hamster ovary cells (CHO-K1) and the mutant type deficient in xylosyltransferase (CHO-745). Fibronectin (FN) was used as substrate for cell attachment. For both cell types, this fucan has shown a dose-dependent anti-adhesive effect, reaching saturation at around 400 mug/mL. This effect was abolished by desulfation of the fucan. In addition, this polymer exhibited the highest inhibitory effect in comparison to other sulfated polysaccharides. The fucan was biotinylated and used as a probe to identify its action sites. Biotinylated fucan was detected in the extracellular matrix environment by confocal microscopy and flow cytometric analysis, but not at the cell surface. The results suggest that the fucan shows anti-adhesive activity by binding directly to FN, and blocking FN sites that are recognized by cell surface ligands, possibly the integrin family.

  8. Genetic effects of the flavonols quercetin, kaempferol, and galangin on Chinese hamster ovary cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Carver, J.H. (Lawrence Livermore National Lab., Livermore, CA); Carrano, A.V.; MacGregor, J.T.

    1983-01-01

    The genotoxicity of selected flavonols was evaluated by multiple endpoints in Chinese hamster ovary (CHO) cells. Chromosomal aberrations, sister-chromatid exchange (SCE), and forward mutation at 4 gene loci were measured in a single population of cells exposed to quercetin, kaempferol, or galangin for 15 h with and without metabolic activation. The incidence of chromosomal aberrations was significantly increased by quercetin in the absence of activation and by kaempferol and galangin with and without activation. Flavanol treatment affected SCE and mutation at the hgprt, aprt, or Na/sup +//K/sup +/-ATPase loci only marginally, but significantly increased mutation frequencies at the tk locus. The response at the tk locus suggests that the CHO cells may behave similarly to L5178Y cells, in which the tk locus is thought to reflect chromosomal lesions in addition to point mutation. These results indicate that, at least under the conditions examined, flavonols induce chromosomal aberrations in CHO cells, but have little effect on point mutation or SCE.

  9. Effect of glutamine limitation on the death of attached Chinese hamster ovary cells

    Energy Technology Data Exchange (ETDEWEB)

    Sanfeliu, A.; Stephanopoulos, G. (Massachusetts Inst. of Tech., Cambridge, MA (United States))

    1999-07-05

    The effect of glutamine depletion on the death of attached Chinese hamster ovary (CHO) cells was investigated. Experiments were performed using an anchorage dependent CHO cell line expressing [gamma]-IFN and a second cell line obtained by transfection of that cell line with the human bcl-2 (hbcl-2). Either cell line could grow in media devoid of glutamine with minimal cell death due to endogenous glutamine synthetase activity that allowed cells to synthesize glutamine from glutamic acid in the medium. However, compared to control cultures in glutamine-containing media, the cell growth rate in glutamine-free media was slower with an increased fraction of cells distributed in the G[sub 0]/G[sub 1] phase. The slower rate of cell cycling apparently protected the cells from entering apoptosis when they were stimulated to proliferate in an environment devoid of other protective factors, such as serum or over-expressed hbcl-2. The depletion of both glutamine and glutamic acid did cause cell death, which could be mitigated by hbcl-2 over-expression.

  10. Genotoxic Effects of PAH Containing Sludge Extracts in Chinese Hamster Ovary Cell Cultures

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    Objective Many studies have been conducted in order to evaluate the genotoxicity of chemicals and waste materials, which utilized in vivo test protocols. The use of animals for routine toxicity testing is now questioned by a growing segment of society[1]. Methods Keeping the above fact in mind, we have conducted in the present study the genotoxicity evaluation of oily sludge samples generated from a petroleum refinery and petrochemical industry and ETP sludge from petroleum refinery using DNA damage, chromosomal aberration, p53 protein induction and apoptosis in short term in vitro mammalian Chinese Hamster Ovary cell cultures. Results It is evident from the results that the oily sludge compounds derived from petroleum refinery and petrochemical industry could cause DNA damage, chromosomal aberration, p53 protein accumulation and apoptotic cell death on exposure to oily sludge extracts in the presence of metabolic activation system (S-9 mix), however, ETP sludge extract could not cause significant genotoxicity in comparison to oily sludge extract and negative control. Conclusion The effect may be attributed to polycyclic aromatic hydrocarbons present in the samples as evidenced from GC-MS.

  11. A Consensus Genome-scale Reconstruction of Chinese Hamster Ovary Cell Metabolism

    KAUST Repository

    Hefzi, Hooman

    2016-11-23

    Chinese hamster ovary (CHO) cells dominate biotherapeutic protein production and are widely used in mammalian cell line engineering research. To elucidate metabolic bottlenecks in protein production and to guide cell engineering and bioprocess optimization, we reconstructed the metabolic pathways in CHO and associated them with >1,700 genes in the Cricetulus griseus genome. The genome-scale metabolic model based on this reconstruction, iCHO1766, and cell-line-specific models for CHO-K1, CHO-S, and CHO-DG44 cells provide the biochemical basis of growth and recombinant protein production. The models accurately predict growth phenotypes and known auxotrophies in CHO cells. With the models, we quantify the protein synthesis capacity of CHO cells and demonstrate that common bioprocess treatments, such as histone deacetylase inhibitors, inefficiently increase product yield. However, our simulations show that the metabolic resources in CHO are more than three times more efficiently utilized for growth or recombinant protein synthesis following targeted efforts to engineer the CHO secretory pathway. This model will further accelerate CHO cell engineering and help optimize bioprocesses.

  12. Killing effect of Chinese hamster V79 cells exposed to accelerated carbon ions and RBE determination

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Survival curves of Chinese hamster V79 cells exposed to accclerated carbon ions with linear energy transfers of 125.5, 200 and 700 keV/μm were measured, respectively. Inactivation cross sections corresponding to the irradiation above were deduced from the V79 cell survival curves. They are 7.86±0.17, 10.44±1.11 and 32.32±3.58 μm2 in turn. With the surviving response of V79 cells to 60Co γ-rays as a reference value, relative biological effectiveness at 10%, 20%, 50% and 80% survival levels were given for the accelerated carbon ions. The results showed that carbon ions with LET of 125.5 keV/μm had a higher value of RBE at all the four survival levels than the carbon ions with other LETs. It was prompted that the maximum value of RBE for the V79 cell surviving as the biological endpoint emerged at the LET below 200 keV/μm for carbon ions.

  13. Killing effect of Chinese hamster V79 cells exposed to accelerated carbon ions and RBE determination

    Institute of Scientific and Technical Information of China (English)

    LIQiang; ZHOUGuang-Ming; 等

    2002-01-01

    Survival curves of Chinese hamster V79 cells exposed to accelerated carbon ions with linear energy transfers of 125.5,200 and 700keV/um were measured,respectively,Inactivation cross sections corresponding to the irradiation above were deduced from the V79 cell survival curves.They are 7.86±0.17,10.44±1.11 and 32.32±3.59um2 in turn.With the surviving response of V79 cells to 60Co γ-rays as a reference value,relative biological effectiveness at 10%,20%,50%and 80% survival levels were given for the accelerated carbon ions,The results showed that carbon ions with LET of 125.5keV/um had a higher value of RBE at all the four survival levels than the carbon ions with other LETs.It was prompted that the maximum value of RBE for the V79 cell surviving as the biological endpoint emerged at the LET below 200keV/um for carbon ions.

  14. Effect of PGE2 on radiation response of chinese hamster V79 cells in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Holahan, E.V.; Blakely, W.F.; Walden, T.L.

    1987-01-01

    Several recent investigations have reported that 16,16-dimethyl prostaglandin E2 (DiPGE2) can protect murine intestinal epithelial cells and hematopoietic stem cells (CFU-S) in vivo from ionizing radiation. It has been postulated that PGE2 may also increase radiation resistance in vitro by stimulating free-radical scavenging or repair systems for oxidative damage. This study reports on the effect of PGE2 in modifying radiation sensitivity in an in vitro mammalian cell line. Chinese hamster V79A03 cells were cultured. Exponentially growing cells were incubated before exposure to graded doses of 250-kVp X rays. Cells were assayed for variations in intracellular levels of cyclic 3',5'-adenosine monophosphate (cAMP), total protein, and glutathione (GSH), and radiation sensitivity was measured by cell survival before and after PGE2 treatment. An acute (2-hr) exposure induced a 25% increase in cAMP content with no significant change in intracellular GSH or protein and no effect on cell survival after exposure to radiation. Chronic exposure to PGE2 increased intracellular GSH, protein, and cAMP levels by 82%, 3%, and 74%, respectively. However, no increase in radiation resistance was apparent following chronic exposure to PGE2. The increased radiation resistance observed in vitro may be due to modifications such as localized tissue or organ-system hypoxia.

  15. Propolis-induced genotoxicity and antigenotoxicity in Chinese hamster ovary cells.

    Science.gov (United States)

    Tavares, Denise Crispim; Mazzaron Barcelos, Gustavo Rafael; Silva, Lívia Ferreira; Chacon Tonin, Conception Cortez; Bastos, Jairo Kenupp

    2006-10-01

    Propolis has been used in folk medicine since ancient times and is known for its antimicrobial, antiparasitic, antiviral, anti-inflammatory, antitumoral and antioxidant properties. In view of the great therapeutic interest in propolis and the small number of studies regarding its mechanism of action, the aim of the present study was to evaluate the mutagenic and antimutagenic effects of propolis using Chinese hamster ovary cells. Parameters such as the frequency of chromosome aberrations and mitotic index were analyzed. The results showed that, on one hand, the highest propolis tested concentration displayed a small but significant increase in the frequency of chromosome aberrations, and on the other hand, it was observed that the lowest tested concentration significantly reduced the chromosome damage induced by the chemotherapeutic agent doxorubicin. The present results indicate that propolis shows the characteristic of a "Janus" compound, i.e., propolis is genotoxic at higher concentrations, while at lower concentrations it display a chemopreventive effect on doxorubicin-induced mutagenicity. Flavonoids may be the components of propolis responsible for its both mutagenic and antimutagenic effects, once these compounds may act either as pro-oxidant or as free radicals scavenger, depending on its concentration.

  16. Characterization of recombinant human erythropoietin produced in Chinese hamster ovary cells

    Energy Technology Data Exchange (ETDEWEB)

    Davis, J.M.; Arakawa, T.; Strickland, T.W.; Yphantis, D.A.

    1987-05-05

    Physicochemical properties of recombinant human erythropoietin were examined. This protein, produced in Chinese hamster ovary cells, showed a conformation apparently identical with the natural product isolated from human urine when examined by circular dichroism, UV absorbance, and fluorescence spectroscopy. Sedimentation equilibrium experiments showed the recombinant erythropoietin preparation to be essentially a single macromolecular component with a molecular weight of 30,400 and a carbohydrate content of 39%. The Stokes radius of recombinant erythropoietin was estimated to be 32 A from gel filtration, much larger than the 20-A radius calculated for a sphere of the observed molecular weight. This difference may be ascribed to the extensive glycosylation. The fluorescence and phosphorescence spectra showed that the luminescent tryptophan(s) is (are) solvent-exposed and can be quenched by I/sup -/ and acrylamide but not by Cs/sup +/. On acid titration, the recombinant erythropoietin showed a conformational transition with a midpoint of pH 4.1. This suggests that the net charges on the protein moiety rather than on the whole molecule play a role in protein structure stability.

  17. Improved antibody production in Chinese hamster ovary cells by ATF4 overexpression.

    Science.gov (United States)

    Haredy, Ahmad M; Nishizawa, Akitoshi; Honda, Kohsuke; Ohya, Tomoshi; Ohtake, Hisao; Omasa, Takeshi

    2013-12-01

    To improve antibody production in Chinese hamster ovary (CHO) cells, the humanized antibody-producing CHO DP-12-SF cell line was transfected with the gene encoding activating transcription factor 4 (ATF4), a central factor in the unfolded protein response. Overexpression of ATF4 significantly enhanced the production of antibody in the CHO DP-12-SF cell line. The specific IgG production rate of in the ATF4-overexpressing CHO-ATF4-16 cells was approximately 2.4 times that of the parental host cell line. Clone CHO-ATF4-16 did not show any change in growth rate compared with the parental cells or mock-transfected CHO-DP12-SF cells. The expression levels of mRNAs encoding both the antibody heavy and light chains in the CHO-ATF4-16 clone were analyzed. This analysis showed that ATF4 overexpression improved the total production and specific production rate of antibody without affecting the mRNA transcription level. These results indicate that ATF4 overexpression is a promising method for improving recombinant IgG production in CHO cells.

  18. Expression, purification, and characterization of human recombinant thrombopoietin in Chinese hamster ovary cells.

    Science.gov (United States)

    Kaszubska, W; Zhang, H; Patterson, R L; Suhar, T S; Uchic, M E; Dickinson, R W; Schaefer, V G; Haasch, D; Janis, R S; DeVries, P J; Okasinski, G F; Meuth, J L

    2000-03-01

    Thrombopoietin (TPO) is a primary regulator of megakaryocytopoiesis, a process through which megakaryocytes proliferate and mature into platelets. Recombinant human TPO (rhTPO) was expressed in Chinese hamster ovary (CHO) cells and purified from the culture medium. The cDNA encoding full-length TPO, including the native signal peptide sequence, was amplified by PCR from a human fetal liver cDNA library. The product was cloned into a mammalian expression vector under the control of the SV40 early promoter and enhancer. Secreted rhTPO was purified in three conventional chromatography steps. It migrates on SDS-PAGE as a broad band, characteristic of a heavily glycosylated protein, with an average molecular mass of 85 kDa. rhTPO expressed in CHO cells is biologically active in vitro as demonstrated by its ability to stimulate the proliferation of a megakaryocytic cell line and to trigger the JAK/STAT signal transduction pathway. rhTPO also shows activity in vivo as judged by the elevation of platelet count in treated mice.

  19. Atomic force microscope tracking observation of Chinese hamster ovary cell mitosis.

    Science.gov (United States)

    Wu, Yangzhe; Cai, Jiye; Cheng, Longqiu; Xu, Yanfang; Lin, Zhiyan; Wang, Chenxi; Chen, Yong

    2006-01-01

    CHO cells possess easily identifiable karyotypes, and CHO cell chromosomes are large and few in number, making these cells ideal for mutational and drug toxicity studies and suitable for investigations of animal chromosome structure. Here, we used atomic force microscopy (AFM) in the tapping mode for detailed visualizations of Chinese hamster ovary (CHO) cell chromosomes during various mitotic phases, including typical prophase, prometaphase, metaphase, anaphase and telophase. Based on our detailed observations, we were able to divide metaphase and anaphase into sub-phases: metaphase I, II and III, and anaphase I and II. Furthermore, we used the AFM error-signal mode to visualize chromosomal ultrastructures and cytokinesis. While these visualizations were all successful, we found that the image quality was affected by cellular debris, contamination. Collectively, our results show that the AFM technique has great potential for the detailed study of chromosomes and chromosomal ultrastructures during all phases of the cell cycle, but that careful standards of sample preparation must be maintained.

  20. Recovery of Chinese hamster ovary host cell proteins for proteomic analysis.

    Science.gov (United States)

    Valente, Kristin N; Schaefer, Amy K; Kempton, Hannah R; Lenhoff, Abraham M; Lee, Kelvin H

    2014-01-01

    Identification and characterization of Chinese hamster ovary (CHO) host cell protein (HCP) impurities by proteomic techniques can aid bioprocess design and lead to more efficient development and improved biopharmaceutical manufacturing operations. Recovery of extracellular CHO HCP for proteomic analysis is particularly challenging due to the relatively low protein concentration and complex composition of media. In this article, we report the development of optimized protocols that improve proteome capture for CHO HCP. Eleven precipitation protocols were screened for protein recovery and optimized for a subset of precipitants by a design of experiments (DOE) approach. Because total protein recovery does not fully replicate a proteomics experiment, or detect non-protein agents that may interfere with proteomic methods, a subset of precipitation conditions were compared by two-dimensional electrophoresis and liquid chromatography coupled with mass spectrometry, with optimized recovery shown to differ between the two proteomic methods. This work demonstrates broadly applicable methods that can be applied as initial steps to optimize sample preparation of any sample type for proteomic analysis, and presents optimized precipitation protocols for extracellular CHO HCP recovery, which can vary appreciably between gel-based and shotgun proteomic methods.

  1. Trehalose suppresses antibody aggregation during the culture of Chinese hamster ovary cells.

    Science.gov (United States)

    Onitsuka, Masayoshi; Tatsuzawa, Miki; Asano, Ryutaro; Kumagai, Izumi; Shirai, Akihiro; Maseda, Hideaki; Omasa, Takeshi

    2014-05-01

    The aggregation of therapeutic antibodies during the manufacturing process is problematic because of the potential risks posed by the aggregates, such as an unexpected immune response. One of the hallmark effects of trehalose, a disaccharide consisting of two alpha-glucose units, is as a chemical chaperone with anti-aggregation activity. In this study, Chinese hamster ovary (CHO) cell line producing a diabody-type bispecific antibody were cultured in medium containing trehalose and the aggregation of the secreted proteins during the culture process was analyzed. An analysis of the various forms of the antibody (monomeric, dimeric, and large aggregates) showed that trehalose decreased the relative content of large aggregates by two thirds. The aggregation kinetics indicated that trehalose directly inhibited the polymerization and aggregation steps in a nucleation-dependent aggregation mechanism. Moreover, both specific and volumetric antibody production were increased in CHO cells cultured in trehalose-containing medium. Thus, the addition of trehalose to recombinant CHO cell cultures would offer a practical strategy for quality improvement in the production of therapeutic antibodies.

  2. Characterization of a Chinese hamster-human hybrid cell line with increased system L amino acid transport activity.

    Science.gov (United States)

    Lobaton, C D; Moreno, A; Oxender, D L

    1984-03-01

    We have studied leucine transport in several Chinese hamster-human hybrid cell lines obtained by fusion of a temperature-sensitive line of Chinese hamster ovary cells, ts025C1, and normal human leukocytes. A hybrid cell line exhibiting a twofold increase in L-leucine uptake over that in the parental cell line was found. This hybrid cell line, 158CnpT-1, was temperature resistant, whereas the parental Chinese hamster ovary mutant, ts025C1, contained a temperature-sensitive leucyl-tRNA synthetase mutation. An examination of the different amino acid transport systems in this hybrid cell line revealed a specific increase of system L activity with no significant changes in systems A and ASC. The Vmax for L-leucine uptake exhibited by the hybrid 158CnpT-1 was twice that in the CHO parental mutant, ts025C1. Cytogenetic analysis showed that the hybrid 158CnpT-1 contains four complete human chromosomes (numbers 4, 5, 10, and 21) and three interspecific chromosomal translocations in a total complement of 34 chromosomes. Biochemical and cytogenetic analysis of segregant clones obtained from hybrid 158CnpT-1 showed that the primary temperature resistance and high system L transport phenotypes can be segregated from this hybrid independently. The loss of the primary temperature resistance was associated with the loss of the human chromosome 5, as previously reported by other laboratories, whereas the loss of the high leucine transport phenotype, which is associated with a lesser degree of temperature resistance, was correlated with the loss of human chromosome 20.

  3. Interphase Death of Chinese Hamster Ovary Cells Exposed to Accelerated Heavy Ions

    Directory of Open Access Journals (Sweden)

    P. Mehnati

    2007-06-01

    Full Text Available Introduction: Heavy ions are nucleus of elements of iron, argon, carbon and neon that all carry positive electrical charges. For these particles to be useful in radiotherapy they need to accelerated to high energy by more than thousand mega volts. Also the cosmic environment is considered to be a complicated mixture of highly energetic photons and heavy ions such as iron. Therefore, the health risks to astronauts during long mission should be considered.  Materials and Methods: The induction of interphase death was tested on Chinese hamster ovary cells by exposing them to accelerated heavy ions (carbon, neon, argon and iron of 10-2000 linear energy transfers (LETs. The fraction of cells that underwent interphase death was determined by observing individual cells with time-lapse photography (direct method as well as by the indirect method of counting cells undergoing interphase death made visible by the addition of caffeine (indirect method. Results: The interphase death due to the exposure to X- rays is increased linearly as the dose exceeds the threshold dose of 10 Gy. Whereas the interphase death increases at a higher rate due to the exposure to high LET heavy ions and no threshold dose was observed. The range of LET values corresponding to the maximum RBE for the interphase death is 120-230 keV/µm. The probability of inducing the interphase death by a single heavy ion traversing through the nucleus is about 0.04-0.08. Discussion and Conclusion: The relative biological effectiveness (RBE of heavy ions as compared to X- rays as determined at the 50% level of induction is increased with LET. It reached a maximum value at a LET of approximately 230 keV/µm and then decreased with further increase in LET. The range of LET values corresponding to the maximum RBE appears to be narrower for interphase death than for reproductive death.

  4. Heterologous expression of active human uridine diphosphate glucuronosyltransferase 1A3 in Chinese hamster lung cells

    Institute of Scientific and Technical Information of China (English)

    Ya-Kun Chen; Xin Li; Shu-Qing Chen; Su Zeng

    2005-01-01

    AIM: To obtain the active human recombinant uridine diphosphate glucuronosyltransferase 1A3 (UGT1A3) enzyme from Chinese hamster lung (CHL) cells.METHODS: The full-length UGT1A3 gene was amplified by reverse transcription-polymerase chain reaction (RT-PCR)using total RNA from human liver as template. The correct fragment confirmed by sequencing was subcloned into the mammalian expression vector pcDNA3.1 (+), and the recombinant vector was transfected into CHL cells using a calcium phosphate method. Expressed UGT1A3 protein was prepared from CHL cells resistant to neomycin (G418). Then the protein was added into a reaction mixture for glucuronidation of quercetin. The glucuronidation activity of UGT1A3 was determined by reverse phase-high performance liquid chromatography (RP-HPLC) coupled with a diode array detector (DAD). The quercetin glucuronide was confirmed by hydrolysis with β-glucuronidase. Control experiments were performed in parallel. The transcriptions of recombinants were also determined by RT-PCR.RESULTS: The gene was confirmed to be an allele (UGT1A3-3) of UGT1A3 by DNA sequencing. The fragment was introduced into pcDNA3.1 (+) successfully. Several colonies were obtained under the selection pressure of G418.The result of RT-PCR showed transcription of recombinants in mRNA level. Glucuronidation assay and HPLC analysis indicated UGT1A3 expressed heterologously in CHL cells was in an active form, and one of the gulcuronides corresponding to quercetin was also detected.CONCLUSION: Correct sequence of UGT1A3 gene can be obtained, and active UGT1A3 enzyme is expressed heterologously in CHL cells.

  5. Diversity in host clone performance within a Chinese hamster ovary cell line.

    Science.gov (United States)

    O'Callaghan, Peter M; Berthelot, Maud E; Young, Robert J; Graham, James W A; Racher, Andrew J; Aldana, Dulce

    2015-01-01

    Much effort has been expended to improve the capabilities of individual Chinese hamster ovary (CHO) host cell lines to synthesize recombinant therapeutic proteins (rPs). However, given the increasing variety in rP molecular types and formats it may be advantageous to employ a toolbox of CHO host cell lines in biomanufacturing. Such a toolbox would contain a panel of hosts with specific capabilities to synthesize certain molecular types at high volumetric concentrations and with the correct product quality (PQ). In this work, we examine a panel of clonally derived host cell lines isolated from CHOK1SV for the ability to manufacture two model proteins, an IgG4 monoclonal antibody (Mab) and an Fc-fusion protein (etanercept). We show that these host cell lines vary in their relative ability to synthesize these proteins in transient and stable pool production format. Furthermore, we examined the PQ attributes of the stable pool-produced Mab and etanercept (by N-glycan ultra performance liquid chromatography (UPLC) and liquid chromatography - tandem mass spectrometry (LC-MS/MS), respectively), and uncovered substantial variation between the host cell lines in Mab N-glycan micro-heterogeneity and etanercept N and O-linked macro-heterogeneity. To further investigate the capabilities of these hosts to act as cell factories, we examined the glycosylation pathway gene expression profiles as well as the levels of endoplasmic reticulum (ER) and mitochondria in the untransfected hosts. We uncovered a moderate correlation between ER mass and the volumetric product concentration in transient and stable pool Mab production. This work demonstrates the utility of leveraging diversity within the CHOK1SV pool to identify new host cell lines with different performance characteristics.

  6. Application of a nonradioactive method of measuring protein synthesis in industrially relevant Chinese hamster ovary cells.

    Science.gov (United States)

    Dadehbeigi, Nazanin; Dickson, Alan James

    2013-01-01

    Due to the high medical and commercial value of recombinant proteins for clinical and diagnostic purposes, the protein synthesis machinery of mammalian host cells is the subject of extensive research by the biopharmaceutical industry. RNA translation and protein synthesis are steps that may determine the extent of growth and productivity of host cells. To address the problems of utilization of current radioisotope methods with proprietary media, we have focused on the application of an alternative method of measuring protein synthesis in recombinant Chinese hamster ovary (CHO) cells. This method employs puromycin as a nonradioactive label which incorporates into nascent polypeptide chains and is detectable by western blotting. This method, which is referred to as SUnSET, successfully demonstrated the expected changes in protein synthesis in conditions that inhibit and restore translation activity and was reproducibly quantifiable. The study of the effects of feed and sodium butyrate addition on protein synthesis by SUnSET revealed an increase following 1 h feed supplementation while a high concentration of sodium butyrate was able to decrease translation during the same treatment period. Finally, SUnSET was used to compare protein synthesis activity during batch culture of the CHO cell line in relation to growth. The results indicate that as the cells approached the end of batch culture, the global rate of protein synthesis declined in parallel with the decreasing growth rate. In conclusion, this method can be used as a "snapshot" to directly monitor the effects of different culture conditions and treatments on translation in recombinant host cells.

  7. Phosphorylation of 3-deazaguanosine by nicotinamide riboside kinase in Chinese hamster ovary cells.

    Science.gov (United States)

    Saunders, P P; Tan, M T; Spindler, C D; Robins, R K

    1989-12-01

    The growth inhibitory activity of 3-deazaguanosine toward a mutant line (TGR-3) of Chinese hamster ovary cells deficient in hypoxanthine-guanine phosphoribosyltransferase (EC 2.4.2.8) was substantially reversed by the simultaneous addition of nicotinamide riboside. The activities of most other ribonucleoside analogues tested were unaffected. The formation of cellular 3-deazaGMP and 3-deazaGTP from the ribonucleoside analogue, as measured by high-pressure liquid chromatography, was inhibited by the presence of nicotinamide riboside. The inhibition was dependent on concentration of 3-deazaguanosine and could also be demonstrated by following the metabolism of 3-deazaguanosine, labeled with 14C in the ribose moiety, to [14C]3-deazaGTP. In the presence of 100 microM nicotinamide riboside formation of the labeled triphosphate derivative of 3-deazaguanosine was undetectable. A 3-deazaguanosine phosphorylating activity was separated from other cellular kinases by DEAE-cellulose chromatography. Contaminating purine nucleoside phosphorylase (EC 2.4.2.1) was subsequently removed by sucrose density gradient centrifugation. The resulting enzyme preparation demonstrated the greatest activities with nicotinamide riboside and 3-deazaguanosine and, in addition, could also phosphorylate tiazofurin and guanosine to lesser, but significant, degrees. These and other observations suggest that 3-deazaguanosine, and perhaps other agents such as tiazofurin, may, at least in part, be phosphorylated by a nicotinamide ribonucleoside kinase in these cells. If so, it is possible that the activity of this agent in other types of cells in vivo could be dependent upon the presence of this enzyme and that it could be influenced by cellular concentrations of the natural pyridine nucleoside.

  8. A quantitative proteomic analysis of cellular responses to high glucose media in Chinese hamster ovary cells.

    Science.gov (United States)

    Liu, Zhenke; Dai, Shujia; Bones, Jonathan; Ray, Somak; Cha, Sangwon; Karger, Barry L; Li, Jingyi Jessica; Wilson, Lee; Hinckle, Greg; Rossomando, Anthony

    2015-01-01

    A goal in recombinant protein production using Chinese hamster ovary (CHO) cells is to achieve both high specific productivity and high cell density. Addition of glucose to the culture media is necessary to maintain both cell growth and viability. We varied the glucose concentration in the media from 5 to 16 g/L and found that although specific productivity of CHO-DG44 cells increased with the glucose level, the integrated viable cell density decreased. To examine the biological basis of these results, we conducted a discovery proteomic study of CHO-DG44 cells grown under batch conditions in normal (5 g/L) or high (15 g/L) glucose over 3, 6, and 9 days. Approximately 5,000 proteins were confidently identified against an mRNA-based CHO-DG44 specific proteome database, with 2,800 proteins quantified with at least two peptides. A self-organizing map algorithm was used to deconvolute temporal expression profiles of quantitated proteins. Functional analysis of altered proteins suggested that differences in growth between the two glucose levels resulted from changes in crosstalk between glucose metabolism, recombinant protein expression, and cell death, providing an overall picture of the responses to high glucose environment. The high glucose environment may enhance recombinant dihydrofolate reductase in CHO cells by up-regulating NCK1 and down-regulating PRKRA, and may lower integrated viable cell density by activating mitochondrial- and endoplasmic reticulum-mediated cell death pathways by up-regulating HtrA2 and calpains. These proteins are suggested as potential targets for bioengineering to enhance recombinant protein production.

  9. Overexpression of Serpinb1 in Chinese hamster ovary cells increases recombinant IgG productivity.

    Science.gov (United States)

    Lin, Nan; Brooks, Jeanne; Sealover, Natalie; George, Henry J; Kayser, Kevin J

    2015-01-10

    We report the discovery and validation of a novel CHO cell engineering target for improving IgG expression, serpin peptidase inhibitor, clade B, member 1 (Serpinb1). Transcriptomic studies using microarrays revealed that Serpinb1 was up-regulated in cultures with IgG heavy and light chain transcription transiently repressed compared with cultures treated with non-targeting siRNA. As proof of concept, a lentiviral vector was employed to overexpress the Chinese Hamster Serpinb1 in a CHOZN(®) Glutamine Synthetase (-/-) recombinant IgG producing CHO line. The lentiviral stable pool demonstrated 4.2-fold SERPINB1 overexpression compared with the non-transduced control. The peak viable cell density (VCD) and peak IgG volumetric productivity of the lentiviral stable pool increased 1.3 and 2.0 fold, respectively, compared with the non-transduced control. For host cell engineering, a plasmid encoding SERPINB1 was transfected into the CHOZN(®) GS (-/-) host cell line to create several stable pools. Single-cell clones isolated from the pools were characterized for their SERPINB1 expression levels and growth. The clone (SERPINB1_OE_27) with the highest SERPINB1 expression had decreased peak viable cell density and exponential phase growth rate. Selected SERPINB1 OE clones were subsequently evaluated for their IgG expression capabilities using GS selection. Clone SERPINB1_OE_42 with moderate SERPINB1 overexpression demonstrated increased IgG productivity in "bulk" selection. We conclude that manipulating Serpinb1 expression can lead to increased recombinant IgG productivity, but the effect in host cell lines may vary by clone and by overexpression level. This work represents the ongoing effort in applying "-omics" findings to novel CHO host cell line engineering.

  10. Metabolomics-driven approach for the improvement of Chinese hamster ovary cell growth: overexpression of malate dehydrogenase II.

    Science.gov (United States)

    Chong, William P K; Reddy, Satty G; Yusufi, Faraaz N K; Lee, Dong-Yup; Wong, Niki S C; Heng, Chew Kiat; Yap, Miranda G S; Ho, Ying Swan

    2010-05-17

    We have established a liquid chromatography-mass spectrometry based metabolomics platform to identify extracellular metabolites in the medium of recombinant Chinese hamster ovary (CHO) fed-batch reactor cultures. Amongst the extracellular metabolites identified, malate accumulation was the most significant. The contributing factors to malate efflux were found to be the supply of aspartate from the medium, and an enzymatic bottleneck at malate dehydrogenase II (MDH II) in the tricarboxylic acid cycle. Subsequent metabolic engineering to overexpress MDH II in CHO resulted in increases in intracellular ATP and NADH, and up to 1.9-fold improvement in integral viable cell number.

  11. Impact of graphene oxide on viability of Chinese hamster ovary and mouse hepatoma MH-22A cells.

    Science.gov (United States)

    Batiuskaite, Danute; Grinceviciute, Nora; Snitka, Valentinas

    2015-08-01

    The evaluation of the cyto- and bio-compatibility is a critical step in the development of graphene oxide (GO) as a new promising material for in vivo biomedical applications. In this study, we report the impact of GO, with and without the addition of bovine serum albumin, on healthy (Chinese hamster ovary) and a cancer (mouse hepatoma MH-22A) cells viability and the estimation of the intracellular distribution of GO inside the cells in vitro. The viability tests were performed using a colony formation assay. The intracellular distribution of GO was estimated using Raman spectroscopy and imaging. The viability of both cell lines decreased with increasing concentration of graphene oxide (12.5-50.0 μg/ml): in the case of Chinese hamster ovary cells viability decreased from 44% to 11%, in the case of mouse hepatoma MH-22A cells--from 22% to 3%. These cell lines significantly differed in their response to GO and GO-BSA formulations. The results of viability tests correlate with results of atomic force microscopy and Raman spectroscopy and imaging findings. The GO influence on cell morphology changes, cell structure, cells colony growth dynamics and GO accumulation inside the cells was higher in the case of mouse hepatoma MH-22A cells.

  12. Conditionally lethal mutations in chinese hamster cells. Characterization of a cell line with a possible defect in the Krebs cycle.

    Science.gov (United States)

    DeFrancesco, L; Werntz, D; Scheffler, I E

    1975-04-01

    A variant Chinese hamster cell line has been isolated from a mutagenized population that has a markedly reduced ability to oxidize a variety of substrates via the Krebs cycle. The production of 14CO2 from 14C-labeled compounds was measured using pyruvate, acetate, beta-hydroxybutyrate, palmitate and glutamate, and in all cases it was neglibible in the mutant. In contrast to this, significant amounts of 14CO2 were produced from 14C-aspartate and 14C-succinate which suggest that some reactions of the Krebs cycle can take place and this conclusion is supported by tracer experiments with labeled compounds. The rate of respiration measured with a Clark oxygen electrode in the mutant was compared to several normal Chinese hamster cell lines and was found to be only 8%. Mitochondria appear to be present in normal numbers and with only minor differences in morphology. The measurement of difference spectra between oxidized and reduced states permits us to conclude that the cytochromes are all present and functional. These results lead us to believe that there may be a defect in the Krebs cycle between alpha-ketoglutarate and succinate. Alternatively a defect in a structural component of the mitochondria or in the electron-transport chain itself may be causing pleiotropic effects in the Krebs cycle and respiration.

  13. Understanding Transcriptional Enhancement in Monoclonal Antibody-Producing Chinese Hamster Ovary Cells

    Science.gov (United States)

    Nicoletti, Sarah E.

    With the demand for monoclonal antibody (mAB) therapeutics continually increasing, the need to better understand what makes a high productivity clone has gained substantial interest. Monoclonal antibody producing Chinese hamster ovary (CHO) cells with different productivities were provided by a biopharmaceutical company for investigation. Gene copy numbers, mRNA levels, and mAb productivities were previously determined for two low producing clones and their amplified progeny. These results showed an increase in mRNA copy number in amplified clones, which correlated to the observed increases in specific productivity of these clones. The presence of multiple copies of mRNA per one copy of DNA in the higher productivity clones has been coined as transcriptional enhancement. The methylation status of the CMV promoter as well as transcription factor/promoter interactions were evaluated to determine the cause of transcriptional enhancement. Methylation analysis via bisulfite sequencing revealed no significant difference in overall methylation status of the CMV promoter. These data did, however, reveal the possibility of differential interactions of transcription factors between the high and low productivity cell clones. This finding was further supported by chromatin immunoprecipitations previously performed in the lab, as well as literature studies. Transcription activator-like effector (TALE) binding proteins were constructed and utilized to selectively immunoprecipitate the CMV promoter along with its associated transcription factors in the different CHO cell clones. Cells were transfected with the TALE proteins, harvested and subjected to a ChIP-like procedure. Results obtained from the TALE ChIP demonstrated the lack of binding of the protein to the promoter and the need to redesign the TALE. Overall, results obtained from this study were unable to give a clear indication as to the causes of transcriptional enhancement in the amplified CHO cell clones. Further

  14. Accelerated Homology-Directed Targeted Integration of Transgenes in Chinese Hamster Ovary Cells Via CRISPR/Cas9 and Fluorescent Enrichment

    DEFF Research Database (Denmark)

    Lee, Jae Seong; Grav, Lise Marie; Pedersen, Lasse Ebdrup

    2016-01-01

    Targeted gene integration into site-specific loci can be achieved in Chinese hamster ovary (CHO) cells via CRISPR/Cas9 genome editing technology and the homology-directed repair (HDR) pathway. The low efficiency of HDR often requires antibiotic selection, which limits targeted integration...

  15. Coordinate amplification of metallothionein I and II genes in cadmium-resistant Chinese hamster cells: implications for mechanisms regulating metallothionein gene expression

    Energy Technology Data Exchange (ETDEWEB)

    Crawford, B.D.; Enger, M.D.; Griffith, B.B.; Griffith, J.K.; Hanners, J.L.; Longmire, J.L.; Munk, A.C.; Stallings, R.L.; Tesmer, J.G.; Walters, R.A.; Hildebrand, C.E.

    1985-02-01

    The authors describe here the derivation, characterization, and use of clonal cadmium-resistance (Cd/sup r) strains of the Chinese hamster cell line CHO which differ in their metallothionein (MT) induction capacity. By nondenaturing polyacrylaminde gel electrophoresis, the authors showed that the stable Cd/sup r/ phenotype is correlated with the augmented expression of both isometallothioneins (MTI and MTII). In cells resistant to concentrations of CdCl2 exceeding 20 M, coordinate amplifications of genes encoding both isometallothioneins was demonstrated by using cDNA MT-coding sequence probes and probes specific for 3'-noncoding regions of Chinese hamster MTI and MTII genes. Molecular and in situ hybridization analyses supported close linkage of Chinese hamster MTI and MTII genes, which the authors have mapped previously to Chinese hamster chromosome 3. This suggests the existence of a functionally related MT gene cluster in this species. Amplified Cd/sup r/ variants expressing abundant MT and their corresponding Cd/sup s/ parental CHO cells should be useful for future studies directed toward elucidating the mechanisms that regulate expressions of the isometallothioneins. 59 references, 8 figures.

  16. A physiological threshold for protection against menadione toxicity by human NAD(P)H : quinone oxidoreductase (NQO1) in Chinese hamster ovary (CHO) cells

    NARCIS (Netherlands)

    Haan, de L.H.J.; Boerboom, A.M.J.F.; Rietjens, I.M.C.M.; Capelle, van D.; Ruijter, de A.J.M.; Jaiswal, A.K.; Aarts, J.M.M.J.G.

    2002-01-01

    NAD(P)H:quinone oxidoreductase 1 (NQO1) has often been suggested to be involved in cancer prevention by means of detoxification of electrophilic quinones. In the present study, a series of Chinese hamster ovary (CHO) cell lines expressing various elevated levels of human NQO1 were generated by stabl

  17. Genomic landscapes of Chinese hamster ovary cell lines as revealed by the Cricetulus griseus draft genome

    DEFF Research Database (Denmark)

    Lewis, Nathan E; Liu, Xin; Li, Yuxiang

    2013-01-01

    . This analysis identified hamster genes missing in different CHO cell lines, and detected >3.7 million single-nucleotide polymorphisms (SNPs), 551,240 indels and 7,063 copy number variations. Many mutations are located in genes with functions relevant to bioprocessing, such as apoptosis. The details...

  18. Temperature dependence of anisotonic NaC1 effect on radiosensitization and ultrastructure of V79 Chinese hamster cells.

    Science.gov (United States)

    Szekely, J G; Raaphorst, G P; Lobreau, A U; Azzam, E I; Copps, T P

    1983-01-01

    Isodose radiation survival of V79 Chinese hamster cells, pretreated with strongly hypertonic concentrations of NaC1 at 22 degrees C, or at 37 degrees C, has been determined and correlated with ultrastructural changes within the nucleus. After an exposure of less than 10 min to 1.5 M NaC1, at both temperatures, the cells are radioprotected, but after longer exposures, the cells treated at 37 degrees C are radiosensitive, whereas those treated at 22 degrees C still show protection. The cells are radiosensitized at both temperatures by pretreatment with 0.5 M and 0.05 M NaC1. The ultrastructure of the nucleus observed after the anisotonic treatments suggests that contraction or swelling of chromatin may be associated with the observed variation in radiation sensitivity.

  19. Influence of DMSO on Carbon K ultrasoft X-rays induced chromosome aberrations in V79 Chinese hamster cells

    Energy Technology Data Exchange (ETDEWEB)

    Natarajan, Adayapalam T., E-mail: natarajan@live.nl [University of Tuscia, Viterbo (Italy); Palitti, Fabrizio [University of Tuscia, Viterbo (Italy); Hill, Mark A. [CRUK/MRC Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Oxford OX3 7DQ (United Kingdom); MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire OX11 0RD (United Kingdom); Stevens, David L. [MRC Radiation and Genome Stability Unit, Harwell, Oxfordshire OX11 0RD (United Kingdom); Ahnstroem, Gunnar [Department of Microbiology and Genetic Toxicology, Stockholm University, Stockholm (Sweden)

    2010-09-10

    Ultrasoft X-rays have been shown to be very efficient in inducing chromosomal aberrations in mammalian cells. The present study was aimed to evaluate the modifying effects of DMSO (a potent scavenger of free radicals) on the frequencies of chromosome aberrations induced by soft X-rays. Confluent held G1 Chinese hamster cells (V79) were irradiated with Carbon K ultrasoft X-rays in the presence and absence of 1 M DMSO and frequencies of chromosome aberrations in the first division cells were determined. DMSO reduced the frequencies of exchange types of aberrations (dicentrics and centric rings) by a factor of 2.1-3.5. The results indicate that free radicals induced by ultrasoft X-rays contribute to a great extent to the induction of chromosome aberrations. The possible implications of these results in interpreting the mechanisms involved in the high efficiency of ultrasoft X-rays in the induction of chromosome aberrations are discussed.

  20. Quantitative feature extraction from the Chinese hamster ovary bioprocess bibliome using a novel meta-analysis workflow

    DEFF Research Database (Denmark)

    Golabgir, Aydin; Gutierrez, Jahir M.; Hefzi, Hooman

    2016-01-01

    The scientific literature concerning Chinese hamster ovary (CHO) cells grows annually due to the importance of CHO cells in industrial bioprocessing of therapeutics. In an effort to start to catalogue the breadth of CHO phenotypes, or phenome, we present the CHO bibliome. This bibliographic......, yielding novel insights and addressing the validity of long held assumptions. Specifically, we show that bioprocess titers can be predicted using indicator variables derived from viable cell density, viability, and culture duration. We further identified a positive correlation between the cumulative viable...... practices can limit research re-use in this field, we show that the statistical analysis of diverse legacy bioprocess data can provide insight into bioprocessing capabilities of CHO cell lines used in industry. The CHO bibliome can be accessed at http://lewislab.ucsd.edu/cho-bibliome/....

  1. Aligned, isotropic and patterned carbon nanotube substrates that control the growth and alignment of Chinese hamster ovary cells

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Che Azurahanim Che; Asanithi, Piyapong; Brunner, Eric W; Jurewicz, Izabela; Bo, Chiara; Sear, Richard P; Dalton, Alan B [Department of Physics and Surrey Materials Institute, University of Surrey, Guildford, Surrey GU2 7XH (United Kingdom); Azad, Chihye Lewis; Ovalle-Robles, Raquel; Fang Shaoli; Lima, Marcio D; Lepro, Xavier; Collins, Steve; Baughman, Ray H, E-mail: r.sear@surrey.ac.uk [Alan G MacDiarmid NanoTech Institute, The University of Texas at Dallas, Richardson, TX 75080-3021 (United States)

    2011-05-20

    Here we culture Chinese hamster ovary cells on isotropic, aligned and patterned substrates based on multiwall carbon nanotubes. The nanotubes provide the substrate with nanoscale topography. The cells adhere to and grow on all substrates, and on the aligned substrate, the cells align strongly with the axis of the bundles of the multiwall nanotubes. This control over cell alignment is required for tissue engineering; almost all tissues consist of oriented cells. The aligned substrates are made using straightforward physical chemistry techniques from forests of multiwall nanotubes; no lithography is required to make inexpensive large-scale substrates with highly aligned nanoscale grooves. Interestingly, although the cells strongly align with the nanoscale grooves, only a few also elongate along this axis: alignment of the cells does not require a pronounced change in morphology of the cell. We also pattern the nanotube bundles over length scales comparable to the cell size and show that the cells follow this pattern.

  2. Aligned, isotropic and patterned carbon nanotube substrates that control the growth and alignment of Chinese hamster ovary cells

    Science.gov (United States)

    Azurahanim Che Abdullah, Che; Asanithi, Piyapong; Brunner, Eric W.; Jurewicz, Izabela; Bo, Chiara; Azad, Chihye Lewis; Ovalle-Robles, Raquel; Fang, Shaoli; Lima, Marcio D.; Lepro, Xavier; Collins, Steve; Baughman, Ray H.; Sear, Richard P.; Dalton, Alan B.

    2011-05-01

    Here we culture Chinese hamster ovary cells on isotropic, aligned and patterned substrates based on multiwall carbon nanotubes. The nanotubes provide the substrate with nanoscale topography. The cells adhere to and grow on all substrates, and on the aligned substrate, the cells align strongly with the axis of the bundles of the multiwall nanotubes. This control over cell alignment is required for tissue engineering; almost all tissues consist of oriented cells. The aligned substrates are made using straightforward physical chemistry techniques from forests of multiwall nanotubes; no lithography is required to make inexpensive large-scale substrates with highly aligned nanoscale grooves. Interestingly, although the cells strongly align with the nanoscale grooves, only a few also elongate along this axis: alignment of the cells does not require a pronounced change in morphology of the cell. We also pattern the nanotube bundles over length scales comparable to the cell size and show that the cells follow this pattern.

  3. Cell growth stimulating effect of Ganoderma lucidum spores and their potential application for Chinese hamster ovary K1 cell cultivation.

    Science.gov (United States)

    Li, Ding; Zhong, Qi; Liu, Tingting; Wang, Jufang

    2016-06-01

    In this work, water-soluble extracts of Ganoderma lucidum spores (Gls), a Chinese medicinal herb that possesses cell growth stimulating function, were found to be an effective growth factor for Chinese hamster ovary (CHO) cell cultivation. The Gls extract was prepared and supplemented to CHO K1 cell culture media with various serum levels. Our results obtained from both the static culture and the spinner-flask suspension culture showed that use of small-amount Gls extract effectively promoted cell growth and suppressed cell apoptosis induced by serum deprivation with normal cell cycle maintained in a low-serum medium. The low-serum medium containing 1 % (v/v) fetal bovine serum (FBS) and 0.01 % (w/v) Gls extract showed a comparable performance on both cell growth and fusion protein productivity with the conventional CHO culture medium containing 10 % (v/v) FBS and a commercial serum-free medium. This is the first study of the potential of Gls extracts for use as an alternative cell growth factor and nutrient for CHO cells. The findings have presented a new approach to economic cultivation of CHO cells for therapeutic protein production.

  4. 放线菌素D对仓鼠成纤维细胞V79靶细胞和旁观者细胞活力和染色体畸变的影响%Effect of actinomycin D on cell viability and chromosome aberration in hamster fibroblast V79 target and bystander cells

    Institute of Scientific and Technical Information of China (English)

    靳翠红; 巫生文; 逯晓波; 刘秋芳; 蔡原; 肖云

    2012-01-01

    目的:观察放线菌素D (actinomycinD,ACTD)对中国仓鼠成纤维细胞V79靶细胞和旁观者细胞的细胞活力和染色体畸变的影响,以确定ACTD能否诱导旁观者效应的发生.方法:用不同剂量ACTD(0、0.25、0.5、1.0、2.0、4.0和8.0 mg/L处理V79靶细胞1h,并选择其中4 mg/L ACTD作用1h开始计时,分别在第4、8、12和24h时取靶细胞去细胞培养液(conditioned medium,CM),培养正常细胞24h后,进行旁观者效应的观察.用MTT法测定靶细胞和旁观者细胞活力;并对靶细胞和旁观者细胞进行染色体畸变分析.结果:随着ACTD剂量的增加,靶细胞的活力下降,存在明显的剂量-效应关系(P<0.05).4 mg/L ACTD作用1h时细胞活力接近50%且稳定.旁观者细胞活力在用4-12 h CM培养时逐渐增加(P<0.05),用24h CM时又下降(P<0.05),4h CM诱导旁观者细胞损伤的作用最强.靶细胞的染色体畸变率随ACTD剂量的增加而增高,具有剂量-效应关系(P<.05).旁观者细胞染色体畸变以4hCM诱导的作用最强,随着加入CM时段的延后,损伤逐渐减轻(P<0.05),在24hCM又趋严重(P<0.05);旁观者细胞与靶细胞染色体畸变类型相似,以断裂为主,伴有少量环形染色体、碎片和双着丝粒染色体.结论:ACTD可以诱导旁观者效应的发生,染色体畸变在靶细胞和旁观者细胞均以断裂为主.%OBJECTIVE: To observe the effect of actinomycin D (ACTD) and conditioned medium on cell viability and chromosome aberration in hamster fibroblast V79 cells to determine whether actinomycin D could induce bystander effect. METHODS: V79 cells were treated with ACTD for 1 h at different doses (0, 0.25, 0.5, 1.0, 2.0, 4.0 and 8.0 mg/L). The 4 mg/L ACTD-conditioned medium(CM) was collected at 4, 8, 12 and 24 h after treatment for 1 h to culture bystander cells to observe the bystander effect. Cell viability was evaluated by MTT assay; chromosome damage was detected using the conventional analysis of

  5. Absence of interaction between X-rays and UV light in inducing ouabain- and thioguanine-resistant mutants in Chinese hamster cells.

    Science.gov (United States)

    Cleaver, J E

    1978-11-01

    Chinese hamster ovary cells were irradiated with X-rays at times from 0 to 17 h before being irradiated with ultraviolet (UV) light. No synergism was observed between the two radiations for the production of mutants resistant to either ouabain or 6-thioguanine. These experiments were designed to test whether X-rays induced an error-prone repair system that would increase the frequency of mutations produced by UV light, but no such system was detected.

  6. Test for Chemical Induction of Chromosome Aberrations in Cultured Chinese Hamster (CHO) Cells With and Without Metabolic Activation. Test Article. Diethylene triamine trinitrate (DETN)

    Science.gov (United States)

    2010-02-25

    chromatid interchanges between chromosomes leading to four-armed configurations. This could be asymmetrical with formation of a dicentric and an acentric...fragment which may be misaligned and a shortened monocentric chromosome , and where there is no sister chromatid union. Dicentric - an asymmetrical...Test for Chemical Induction of Chromosome Aberrations in Cultured Chinese Hamster Ovary (CHO) Cells With and Without Metabolic Activation Test

  7. Chinese hamster ovary (CHO) host cell engineering to increase sialylation of recombinant therapeutic proteins by modulating sialyltransferase expression.

    Science.gov (United States)

    Lin, Nan; Mascarenhas, Joaquina; Sealover, Natalie R; George, Henry J; Brooks, Jeanne; Kayser, Kevin J; Gau, Brian; Yasa, Isil; Azadi, Parastoo; Archer-Hartmann, Stephanie

    2015-01-01

    N-Glycans of human proteins possess both α2,6- and α2,3-linked terminal sialic acid (SA). Recombinant glycoproteins produced in Chinese hamster overy (CHO) only have α2,3-linkage due to the absence of α2,6-sialyltransferase (St6gal1) expression. The Chinese hamster ST6GAL1 was successfully overexpressed using a plasmid expression vector in three recombinant immunoglobulin G (IgG)-producing CHO cell lines. The stably transfected cell lines were enriched for ST6GAL1 overexpression using FITC-Sambucus nigra (SNA) lectin that preferentially binds α2,6-linked SA. The presence of α2,6-linked SA was confirmed using a novel LTQ Linear Ion Trap Mass Spectrometry (LTQ MS) method including MSn fragmentation in the enriched ST6GAL1 Clone 27. Furthermore, the total SA (mol/mol) in IgG produced by the enriched ST6GAL1 Clone 27 increased by 2-fold compared to the control. For host cell engineering, the CHOZN(®) GS host cell line was transfected and enriched for ST6GAL1 overexpression. Single-cell clones were derived from the enriched population and selected based on FITC-SNA staining and St6gal1 expression. Two clones ("ST6GAL1 OE Clone 31 and 32") were confirmed for the presence of α2,6-linked SA in total host cell protein extracts. ST6GAL1 OE Clone 32 was subsequently used to express SAFC human IgG1. The recombinant IgG expressed in this host cell line was confirmed to have α2,6-linked SA and increased total SA content. In conclusion, overexpression of St6gal1 is sufficient to produce recombinant proteins with increased sialylation and more human-like glycoprofiles without combinatorial engineering of other sialylation pathway genes. This work represents our ongoing effort of glycoengineering in CHO host cell lines for the development of "bio-better" protein therapeutics and cell culture vaccine production.

  8. Anticancer Effects of Fusion Protein CAtin on DMBA-induced Carcinogenesis in Buccal Pouch of Chinese Hamster

    Institute of Scientific and Technical Information of China (English)

    BAI Jie-ying; LI Xiao; LI Chang; ZHANG Xiao-fei; LI Zhi-xin; ZHAO Shuang; LIU Xiao; ZENG Lin; CHI Bao-rong

    2012-01-01

    Aberrant expression ofcarcinoembryonic antigen(CEA)is a common feature for multiple types of cancer,which makes it an attractive target for anticancer therapy.CAtin is a novel dual cancer-specific fusion protein,composed of an anti-CEA single-chain disulfide-stabilized Fv antibody(scdsFv)and Apoptin,a tumor-specific apoptosis-inducing protein.Oral squamous cell carcinoma(OSCC)is an important healthcare problem in the clinic.To evaluate the anticancer effects of CAtin on OSCC,7,12-dimethylbenz[a]anthracene(DMBA)was used to induce oral carcinogenesis and premalignant lesions in the buccal pouch of Chinese hamster,and the antitumor effects of CAtin were determined in pre-cancer,cancer and post-operatative cancer models,respectively.The results show that the administration of CAtin delayed the malignant transformation of early stage cancerous lesions,inhibited the growth of established solid oral tumors and reduced the post-operatative relapse of lesions,with no significant systemic toxicity.This study demonstrates that CAtin may have potential for the treatment of OSCC,and the development of preventive strategies based on CAtin may offer a practical approach for the treatment of human oral tumors.

  9. Size distribution of fullerenol nanoparticles in cell culture medium and their influence on antioxidative enzymes in Chinese hamster ovary cells

    Directory of Open Access Journals (Sweden)

    Srđenović Branislava U.

    2015-01-01

    Full Text Available Fullerenol (C60(OH24 nanoparticles (FNP have a significant role in biomedical research due to their numerous biological activities, some of which are cytoprotective and antioxidative properties. The aim of this study was to measure distribution of fullerenol nanoparticles and zeta potential in cell medium RPMI 1640 with 10% fetal bovine serum (FBS and to investigate the influence of FNP on Chinese hamster ovary cells (CHO-K1 survival, as well as to determine the activity of three antioxidative enzymes: superoxide-dismutase, glutathione-reductase and glutathione-S-transferase in mitomycin C-treated cell line. Our investigation implies that FNP, as a strong antioxidant, influence the cellular redox state and enzyme activities and thus may reduce cell proliferation, which confirms that FNP could be exploited for its use as a cytoprotective agent.[Projekat Ministarstva nauke Republike Srbije, br. III45005 i Pokrajinski Sekretarijat za nauku i tehnološki razvoj Vojvodine, grant number 114-451-2056/2011-01

  10. Chinese hamster ovary cell performance enhanced by a rational divide-and-conquer strategy for chemically defined medium development.

    Science.gov (United States)

    Liu, Yaya; Zhang, Weiyan; Deng, Xiancun; Poon, Hong Fai; Liu, Xuping; Tan, Wen-Song; Zhou, Yan; Fan, Li

    2015-12-01

    Basal medium design is considered one of the most important steps in process development. To optimize chemically defined (CD) media efficiently and effectively for the biopharmaceutical industry, a two-step rational strategy was applied to optimize four antibody producing Chinese hamster ovary (CHO) cell lines. In the first step, 48 of 52 components of our in-house medium were divided into three groups according to their characteristics. In the next step, these groups were optimized by spent medium analysis, response surface methodology and mixture design. Because these steps in our strategy involved dividing medium components into groups and subsequently adjusting the concentration of the components, we termed this medium development strategy "divide and conquer". By applying the strategy, we were able to improve the titers of CHO-S, CHO-DG44 and two CHO-K1 cell lines 1.92, 1.86, 2.92 and 1.62-fold, respectively, in 8 weeks with fewer than 60 tests. This divide-and-conquer strategy was efficient, effective, scalable and universal in our current study and offered a new approach to CD media development.

  11. A Systematic Approach to Time-series Metabolite Profiling and RNA-seq Analysis of Chinese Hamster Ovary Cell Culture

    Science.gov (United States)

    Hsu, Han-Hsiu; Araki, Michihiro; Mochizuki, Masao; Hori, Yoshimi; Murata, Masahiro; Kahar, Prihardi; Yoshida, Takanobu; Hasunuma, Tomohisa; Kondo, Akihiko

    2017-01-01

    Chinese hamster ovary (CHO) cells are the primary host used for biopharmaceutical protein production. The engineering of CHO cells to produce higher amounts of biopharmaceuticals has been highly dependent on empirical approaches, but recent high-throughput “omics” methods are changing the situation in a rational manner. Omics data analyses using gene expression or metabolite profiling make it possible to identify key genes and metabolites in antibody production. Systematic omics approaches using different types of time-series data are expected to further enhance understanding of cellular behaviours and molecular networks for rational design of CHO cells. This study developed a systematic method for obtaining and analysing time-dependent intracellular and extracellular metabolite profiles, RNA-seq data (enzymatic mRNA levels) and cell counts from CHO cell cultures to capture an overall view of the CHO central metabolic pathway (CMP). We then calculated correlation coefficients among all the profiles and visualised the whole CMP by heatmap analysis and metabolic pathway mapping, to classify genes and metabolites together. This approach provides an efficient platform to identify key genes and metabolites in CHO cell culture. PMID:28252038

  12. ¹H NMR spectroscopy profiling of metabolic reprogramming of Chinese hamster ovary cells upon a temperature shift during culture.

    Directory of Open Access Journals (Sweden)

    Jane L Wagstaff

    Full Text Available We report an NMR based approach to determine the metabolic reprogramming of Chinese hamster ovary cells upon a temperature shift during culture by investigating the extracellular cell culture media and intracellular metabolome of CHOK1 and CHO-S cells during culture and in response to cold-shock and subsequent recovery from hypothermic culturing. A total of 24 components were identified for CHOK1 and 29 components identified for CHO-S cell systems including the observation that CHO-S media contains 5.6 times the level of glucose of CHOK1 media at time zero. We confirm that an NMR metabolic approach provides quantitative analysis of components such as glucose and alanine with both cell lines responding in a similar manner and comparable to previously reported data. However, analysis of lactate confirms a differentiation between CHOK1 and CHO-S and that reprogramming of metabolism in response to temperature was cell line specific. The significance of our results is presented using principal component analysis (PCA that confirms changes in metabolite profile in response to temperature and recovery. Ultimately, our approach demonstrates the capability of NMR providing real-time analysis to detect reprogramming of metabolism upon cellular perception of cold-shock/sub-physiological temperatures. This has the potential to allow manipulation of metabolites in culture supernatant to improve growth or productivity.

  13. Viable cell recycle with an inclined settler in the perfusion culture of suspended recombinant Chinese hamster ovary cells.

    Science.gov (United States)

    Searles, J A; Todd, P; Kompala, D S

    1994-01-01

    The perfusion culture of suspended mammalian cells requires a cell retention device, the best of which will retain all viable cells and reject all nonviable cells and debris. The inclined settler is a passive, simple, inexpensive, and easy-to-maintain device that has been shown in the past to selectively remove single nonviable cells of hybridoma cultures. In this work, we have demonstrated the preferential return of viable recombinant Chinese hamster ovary (CHO) cells through the use of a three-port settler maintained at lower temperatures and vibrated to reduce cell attachment and enhance cell return to the bioreactor. The residence time of CHO cells in the cooled, vibrated settler was determined by flow-cytometric discrimination of tracer recombinant CHO cells. Cells returning to the bioreactor through the underflow had an average residence time of 1.46 h in the settler. During perfusion cultures with cell densities above 10(6) cells/mL, cells seen to be stalled within the settler were easily dislodged by periodic air bubbling using a simple back-flushing procedure in which headspace gas was brought through the settler underflow port. The resuspended cells were returned to the bioreactor within an average of 32 min after bubbling. This study demonstrates that inclined sedimentation technology can be utilized to selectively recycle viable recombinant CHO cells with only a short retention time in an inclined settler.

  14. Interlaboratory studies with the Chinese hamster V79 cell metabolic cooperation assay to detect tumor-promoting agents

    Energy Technology Data Exchange (ETDEWEB)

    Bohrman, J.S.; Burg, J.R.; Elmore, E.; Gulati, D.K.; Barfknecht, T.R.; Niemeier, R.W.; Dames, B.L.; Toraason, M.; Langenbach, R.

    1988-01-01

    Three laboratories participated in an interlaboratory study to evaluate the usefulness of the Chinese hamster V79 cell metabolic cooperation assay to predict the tumor-promoting activity of selected chemical. Twenty-three chemicals of different chemical structures (phorbol esters, barbiturates, phenols, artificial sweeteners, alkanes, and peroxides) were chosen for testing based on in vivo promotion activities, as reported in the literature. Assay protocols and materials were standardized, and the chemicals were coded to facilitate unbiased evaluation. A chemical was tested only once in each laboratory, with one of the three laboratories testing only 15 out of 23 chemicals. Dunnett's test was used for statistical analysis. Chemicals were scored as positive (at least two concentration levels statistically different than control), equivocal (only one concentration statistically different), or negative. For 15 chemicals tested in all three laboratories, there was complete agreement among the laboratories for nine chemicals. For the 23 chemicals tested in only two laboratories, there was agreement on 16 chemicals. With the exception of the peroxides and alkanes, the metabolic cooperation data were in general agreement with in vivo data. However, an overall evaluation of the V79 cell system for predicting in vivo promotion activity was difficult because of the organ specificity of certain chemicals and/or the limited number of adequately tested nonpromoting chemicals.

  15. TOXICOLOGY STUDIES OF LEWISITE AND SULFUR MUSTARD AGENTS:GENETIC TOXICITY OF LEWISITE (L) IN CHINESE HAMSTER OVARY CELLS

    Energy Technology Data Exchange (ETDEWEB)

    Jostes,R.F. Jr.; Sasser, LB; Rausch, R.J.

    1989-05-31

    The cytotoxic clastogenic and mutagenic effects of the arsenic containing vesicant, Lewisite (L) [dichloro(2-chlorovinyl) arsine], have been investigated using Chinese hamster ovary cells. One hour exposures to Lewisite were cytotoxic in uM amounts. The cell survival response yields a D37 of 0.6 uM and an extrapolation number of 2.5. The mutagenic response at the hypoxantnine-guanine phosporibosyl transferase (HGPRT) locus was sporadic and not significantly greater than control values when cells were exposed over a range of 0.125 to2.0 uM. Sister chromatid exchange (SCE) induction, a measure of chromosomal rearrangement, was weakly positive over a range of 0.25 to 1.0 uM but the values were not significantly greater than the control response. Chromosomal aberrations were induced at 0.75 and 1.0 UMin one experiment and 0.5 and 0.75 uM in another experiment. The Induced values were significantly greater than the control values. Lewisite appears to be cytotoxic and clastogenic in our investigations but SCE and mutation at the HGPRT locus are not significantly greater than control values. Lewisita toxicity was in some ways similar to radiomimetic chemicals such as bleomycin.

  16. Increased recombinant protein production owing to expanded opportunities for vector integration in high chromosome number Chinese hamster ovary cells.

    Science.gov (United States)

    Yamano, Noriko; Takahashi, Mai; Ali Haghparast, Seyed Mohammad; Onitsuka, Masayoshi; Kumamoto, Toshitaka; Frank, Jana; Omasa, Takeshi

    2016-08-01

    Chromosomal instability is a characteristic of Chinese hamster ovary (CHO) cells. Cultures of these cells gradually develop heterogeneity even if established from a single cell clone. We isolated cells containing different numbers of chromosomes from a CHO-DG44-based human granulocyte-macrophage colony stimulating factor (hGM-CSF)-producing cell line and found that high chromosome number cells showed higher hGM-CSF productivity. Therefore, we focused on the relationship between chromosome aneuploidy of CHO cells and high recombinant protein-producing cell lines. Distribution and stability of chromosomes were examined in CHO-DG44 cells, and two cell lines expressing different numbers of chromosomes were isolated from the original CHO-DG44 cell line to investigate the effect of aneuploid cells on recombinant protein production. Both cell lines were stably transfected with a vector that expresses immunoglobulin G3 (IgG3), and specific antibody production rates were compared. Cells containing more than 30 chromosomes had higher specific antibody production rates than those with normal chromosome number. Single cell analysis of enhanced green fluorescent protein (Egfp)-gene transfected cells revealed that increased GFP expression was relative to the number of gene integration sites rather than the difference in chromosome numbers or vector locations. Our results suggest that CHO cells with high numbers of chromosomes contain more sites for vector integration, a characteristic that could be advantageous in biopharmaceutical production.

  17. New cell line development for antibody-producing Chinese hamster ovary cells using split green fluorescent protein

    Directory of Open Access Journals (Sweden)

    Kim Yeon-Gu

    2012-05-01

    Full Text Available Abstract Background The establishment of high producer is an important issue in Chinese hamster ovary (CHO cell culture considering increased heterogeneity by the random integration of a transfected foreign gene and the altered position of the integrated gene. Fluorescence-activated cell sorting (FACS-based cell line development is an efficient strategy for the selection of CHO cells in high therapeutic protein production. Results An internal ribosome entry site (IRES was introduced for using two green fluorescence protein (GFP fragments as a reporter to both antibody chains, the heavy chain and the light chain. The cells co-transfected with two GFP fragments showed the emission of green fluorescence by the reconstitution of split GFP. The FACS-sorted pool with GFP expression had a higher specific antibody productivity (qAb than that of the unsorted pool. The qAb was highly correlated with the fluorescence intensity with a high correlation coefficient, evidenced from the analysis of median GFP and qAb in individual selected clones. Conclusions This study proved that the fragment complementation for split GFP could be an efficient indication for antibody production on the basis of high correlation of qAb with reconstitution of GFP. Taken together, we developed an efficient FACS-based screening method for high antibody-producing CHO cells with the benefits of the split GFP system.

  18. Identification of a functional antioxidant responsive element in the promoter of the Chinese hamster carbonyl reductase 3 (Chcr3) gene.

    Science.gov (United States)

    Miura, Takeshi; Taketomi, Ayako; Nakabayashi, Toshikatsu; Nishinaka, Toru; Terada, Tomoyuki

    2015-07-01

    CHCR3, a member of the short-chain dehydrogenase/reductase superfamily, is a carbonyl reductase 3 enzyme in Chinese hamsters. Carbonyl reductase 3 in humans has been believed to involve the metabolism and/or pharmacokinetics of anthracycline drugs, and the mechanism underlying the gene regulation has been investigated. In this study, the nucleotide sequence of the Chcr3 promoter was originally determined, and its promoter activity was characterised. The proximal promoter region is TATA-less and GC-rich, similar to the promoter region of human carbonyl reductase 3. Cobalt stimulated the transcriptional activity of the Chcr3 gene. The results of a luciferase gene reporter assay demonstrated that cobalt-induced stimulation required an antioxidant responsive element. Forced expression of Nrf2, the transcription factor that binds to antioxidant responsive elements, enhanced the transcriptional activity of the Chcr3 gene. These results suggest that cobalt induces the expression of the Chcr3 gene via the Nrf2-antioxidant responsive element pathway.

  19. Efficient enrichment of high-producing recombinant Chinese hamster ovary cells for monoclonal antibody by flow cytometry.

    Science.gov (United States)

    Okumura, Takeshi; Masuda, Kenji; Watanabe, Kazuhiko; Miyadai, Kenji; Nonaka, Koichi; Yabuta, Masayuki; Omasa, Takeshi

    2015-09-01

    To screen a high-producing recombinant Chinese hamster ovary (CHO) cell from transfected cells is generally laborious and time-consuming. We developed an efficient enrichment strategy for high-producing cell screening using flow cytometry (FCM). A stable pool that had possibly shown a huge variety of monoclonal antibody (mAb) expression levels was prepared by transfection of an expression vector for mAb production to a CHO cell. To enrich high-producing cells derived from a stable pool stained with a fluorescent-labeled antibody that binds to mAb presented on the cell surface, we set the cell size and intracellular density gates based on forward scatter (FSC) and side scatter (SSC), and collected the brightest 5% of fluorescein isothiocyanate (FITC)-positive cells from each group by FCM. The final product concentration in a fed-batch culture of cells sorted without FSC and SSC gates was 1.2-1.3-times higher than that of unsorted cells, whereas that of cells gated by FSC and SSC was 3.4-4.7-fold higher than unsorted cells. Surprisingly, the fraction with the highest final product concentration indicated the smallest value of FSC and SSC, and the middle value of fluorescence intensity among all fractionated cells. Our results showed that our new screening strategy by FCM based on FSC and SSC gates could achieve an efficient enrichment of high-producing cells with the smallest value of FSC and SSC.

  20. Hypothermia enhances bcl-2 expression and protects against oxidative stress-induced cell death in Chinese hamster ovary cells.

    Science.gov (United States)

    Slikker, W; Desai, V G; Duhart, H; Feuers, R; Imam, S Z

    2001-08-01

    Oxidative stress is one of the major causes of cellular injury. Various reactive oxygen (ROS) and nitrogen (RNS) species such as superoxide, hydroxyl radical, peroxynitrite, and nitric oxide are involved in the manifestations of different types of organ toxicity and the resultant syndromes, symptoms, or diseases. Hypothermic conditions have been reported to reduce the oxidative stress in various in vitro and in vivo studies. In the present study, we sought to determine the effect of lowered temperatures on oxidative stress-induced cell death in Chinese hamster ovary (CHO) cells. We also investigated the oxidative stress-induced alterations in the expression of anti-apoptotic protein, bcl-2, in CHO cells at lowered temperatures. CHO cells were incubated at four different temperatures of 30, 32, 35, and 37 degrees C (control temperature) from 1 to 4 d. In another set, the cells were incubated with 100 microM hydrogen peroxide (H(2)O(2)) for 30 min before harvesting at different time points. The cells were harvested at 1, 2, 3, and 4 d. Cell survival was significantly higher at 30 degrees C as compared to 37 degrees C over 4 d of incubation. In cells incubated with H(2)O(2), significantly higher cell viability was observed at lower temperatures as compared to the cells incubated at 37 degrees C. The activity of glutathione peroxidase (GSH-Px) also increased significantly at lower temperatures. Lowered temperature also provided a significant increase in the expression of anti-apoptotic protein, bcl-2 after 4 d of incubation. These data suggest that hypothermic conditions lowers the risk of oxidative stress-induced cellular damage and programmed cell death by increasing the activity of GSH-Px and by the induction in the expression of the anti-apoptotic protein, bcl-2.

  1. Model-directed engineering of "difficult-to-express" monoclonal antibody production by Chinese hamster ovary cells.

    Science.gov (United States)

    Pybus, Leon P; Dean, Greg; West, Nathan R; Smith, Andrew; Daramola, Olalekan; Field, Ray; Wilkinson, Stephen J; James, David C

    2014-02-01

    Despite improvements in volumetric titer for monoclonal antibody (MAb) production processes using Chinese hamster ovary (CHO) cells, some "difficult-to-express" (DTE) MAbs inexplicably reach much lower process titers. These DTE MAbs require intensive cell line and process development activity, rendering them more costly or even unsuitable to manufacture. To rapidly and rationally identify an optimal strategy to improve production of DTE MAbs, we have developed an engineering design platform combining high-yielding transient production, empirical modeling of MAb synthesis incorporating an unfolded protein response (UPR) regulatory loop with directed expression and cell engineering approaches. Utilizing a panel of eight IgG1 λ MAbs varying >4-fold in volumetric titer, we showed that MAb-specific limitations on folding and assembly rate functioned to induce a proportionate UPR in host CHO cells with a corresponding reduction in cell growth rate. Derived from comparative empirical modeling of cellular constraints on the production of each MAb we employed two strategies to increase production of DTE MAbs designed to avoid UPR induction through an improvement in the rate/cellular capacity for MAb folding and assembly reactions. Firstly, we altered the transfected LC:HC gene ratio and secondly, we co-expressed a variety of molecular chaperones, foldases or UPR transactivators (BiP, CypB, PDI, and active forms of ATF6 and XBP1) with recombinant MAbs. DTE MAb production was significantly improved by both strategies, although the mode of action was dependent upon the approach employed. Increased LC:HC ratio or CypB co-expression improved cell growth with no effect on qP. In contrast, BiP, ATF6c and XBP1s co-expression increased qP and reduced cell growth. This study demonstrates that expression-engineering strategies to improve production of DTE proteins in mammalian cells should be product specific, and based on rapid predictive tools to assess the relative impact of

  2. Novel Role of ER Stress and Autophagy in Microcystin-LR Induced Apoptosis in Chinese Hamster Ovary Cells

    Science.gov (United States)

    Zhang, Shenshen; Liu, Chuanrui; Li, Yang; Imam, Mustapha U.; Huang, Hui; Liu, Haohao; Xin, Yongjuan; Zhang, Huizhen

    2016-01-01

    Microcystin-LR (MC-LR) is a ubiquitous peptide that exhibits strong reproductive toxicity, although the mechanistic basis for such toxicity remains largely unknown. The present study was conducted to investigate the mechanisms underlying the adverse effects of exposure to MC-LR in Chinese hamster ovary (CHO) cells. The results showed that MC-LR inhibited the in vitro proliferation of CHO cells significantly, with an IC50 of 10 μM. Moreover, MC-LR-treated CHO cells revealed strong induction of cell cycle arrest and apoptosis. Additionally, exposure of CHO cells to MC-LR resulted in excess reactive oxygen species production and intracellular calcium release, with resultant endoplasmic reticulum stress (ERs). There was also extensive accumulation of autophagic vacuoles with the highest concentration of MC-LR used (10 μM). Furthermore, the expression of ERs (GRP78, ATF-6, PERK, IRE1, CHOP) and autophagy (Beclin1 and LC3II) proteins was increased, with concomitantly reduced expression of LC3I suggesting that ERs and autophagy were induced in CHO cells by MC-LR treatment. Conversely, pretreatment of CHO cells with 4-Phenyl butyric acid, the ERs inhibitor reduced the MC-LR-induced apoptotic cell death and cellular autophagy as evidenced by the reduced expression of Beclin1 and LC3II. Similarly, MC-LR treatment in combination with an autophagy inhibitor (3-methyladenine) increased apoptotic cell death compared with MC-LR alone, and induced ERs via upregulating ERs proteins. The overall results indicated that activation of ERs and autophagy are both associated with MC-LR-induced apoptosis in CHO cells. ERs may be a trigger of autophagy in this process. PMID:27877136

  3. Multi-omic profiling -of EPO-producing Chinese hamster ovary cell panel reveals metabolic adaptation to heterologous protein production.

    Science.gov (United States)

    Ley, Daniel; Seresht, Ali Kazemi; Engmark, Mikael; Magdenoska, Olivera; Nielsen, Kristian Fog; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    2015-11-01

    Chinese hamster ovary (CHO) cells are the preferred production host for many therapeutic proteins. The production of heterologous proteins in CHO cells imposes a burden on the host cell metabolism and impact cellular physiology on a global scale. In this work, a multi-omics approach was applied to study the production of erythropoietin (EPO) in a panel of CHO-K1 cells under growth-limited and unlimited conditions in batch and chemostat cultures. Physiological characterization of the EPO-producing cells included global transcriptome analysis, targeted metabolome analysis, including intracellular pools of glycolytic intermediates, NAD(P)H/NAD(P)(+) , adenine nucleotide phosphates (ANP), and extracellular concentrations of sugars, organic acids, and amino acids. Potential impact of EPO expression on the protein secretory pathway was assessed at multiple stages using quantitative PCR (qPCR), reverse transcription PCR (qRT-PCR), Western blots (WB), and global gene expression analysis to assess EPO gene copy numbers, EPO gene expression, intracellular EPO retention, and differentially expressed genes functionally related to secretory protein processing, respectively. We found no evidence supporting the existence of production bottlenecks in energy metabolism (i.e., glycolytic metabolites, NAD(P)H/NAD(P)(+) and ANPs) in batch culture or in the secretory protein production pathway (i.e., gene dosage, transcription and post-translational processing of EPO) in chemostat culture at specific productivities up to 5 pg/cell/day. Time-course analysis of high- and low-producing clones in chemostat culture revealed rapid adaptation of transcription levels of amino acid catabolic genes in favor of EPO production within nine generations. Interestingly, the adaptation was followed by an increase in specific EPO productivity.

  4. Thresholds for phosphatidylserine externalization in Chinese hamster ovarian cells following exposure to nanosecond pulsed electrical fields (nsPEF.

    Directory of Open Access Journals (Sweden)

    Rebecca L Vincelette

    Full Text Available High-amplitude, MV/m, nanosecond pulsed electric fields (nsPEF have been hypothesized to cause nanoporation of the plasma membrane. Phosphatidylserine (PS externalization has been observed on the outer leaflet of the membrane shortly after nsPEF exposure, suggesting local structural changes in the membrane. In this study, we utilized fluorescently-tagged Annexin V to observe the externalization of PS on the plasma membrane of isolated Chinese Hamster Ovary (CHO cells following exposure to nsPEF. A series of experiments were performed to determine the dosimetric trends of PS expression caused by nsPEF as a function of pulse duration, τ, delivered field strength, ED, and pulse number, n. To accurately estimate dose thresholds for cellular response, data were reduced to a set of binary responses and ED50s were estimated using Probit analysis. Probit analysis results revealed that PS externalization followed the non-linear trend of (τ*ED (2(-1 for high amplitudes, but failed to predict low amplitude responses. A second set of experiments was performed to determine the nsPEF parameters necessary to cause observable calcium uptake, using cells preloaded with calcium green (CaGr, and membrane permeability, using FM1-43 dye. Calcium influx and FM1-43 uptake were found to always be observed at lower nsPEF exposure parameters compared to PS externalization. These findings suggest that multiple, higher amplitude and longer pulse exposures may generate pores of larger diameter enabling lateral diffusion of PS; whereas, smaller pores induced by fewer, lower amplitude and short pulse width exposures may only allow extracellular calcium and FM1-43 uptake.

  5. Exploring the capabilities of fluorometric online monitoring on chinese hamster ovary cell cultivations producing a monoclonal antibody.

    Science.gov (United States)

    Schwab, Karen; Amann, Thomas; Schmid, Jakob; Handrick, René; Hesse, Friedemann

    2016-11-01

    Online monitoring of Chinese hamster ovary fed-batch cell cultures via two-dimensional fluorescence spectroscopy (2DFS) was evaluated in this work. Particular attention was directed toward different process strategies regarding the use of nutrient-rich feed media and temperature shifts. These intentionally performed process manipulations broadened the variances in the obtained fluorescence spectra and this was suspected to hamper the generation of reliable soft sensors. Principal component analysis of the obtained fluorescence data showed that temperature shift and feeding strategy had a considerable impact on the fluorescence signals. Partial least square regression models were calculated for the prediction of glucose, lactate, monoclonal antibody (mAb), and viable cell concentrations (VCC). It was aimed to integrate all 2DFS datasets in the respective calibration models regardless of the process-strategy-dependent diversity. Contrary to the expectations, it was feasible to calibrate soft sensors for the online prediction of glucose (7 latent variables (LVs), Rcal2 = 0.97, rout mean squared error of prediction (RMSEP) = 1.1 g L(-1) ), lactate (5 LV; Rcal2 = 0.96; RMSEP = 0.5 g L(-1) ) and mAb concentrations (4 LV; Rcal2 = 0.99; RMSEP = 11.4 mg L(-1) ). Feeding and temperature shifts had the highest impact on the VCC model (3 LV; Rcal2 = 0.94; RMSEP 3.8 × 10(5) mL(-1) ), nevertheless the prediction of VCC from the fed-batch 2DFS data was feasible. The results strongly indicate that variances in the datasets due to the process strategy can be tolerated to some extent by the respective soft sensors. © 2016 American Institute of Chemical Engineers Biotechnol. Prog., 32:1592-1600, 2016.

  6. Protective effect of propolis on radiation-induced chromosomal damage on Chinese hamster ovary cells (CHO-K1)

    Energy Technology Data Exchange (ETDEWEB)

    Spigoti, Geyza; Bartolini, Paolo; Okazaki, Kayo [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil)], e-mail: kokazaki@ipen.br; Tsutsumi, Shiguetoshi [Amazon Food Ltd., Tokyo (Japan)], e-mail: fwip5138@mb.infoweb.ne.jp

    2009-07-01

    In the last years, particular interest has been given to investigations concerning natural, effective and nontoxic compounds with radioprotective capacity in concert with increasing utilization of different types of ionizing radiation for various applications. Among them, propolis, a resinous mixture of substances collected by honey bees (Apis mellifera) has been considered promising since it presents several advantageous characteristics, i.e., antiinflammatory, anticarcinogenic, antimicrobial and free radical scavenging action. It is, therefore, a direct antioxidant that protects cells and organisms from the adverse effects of ionizing radiation. These relevant biological activities are mainly mediated by the flavonoids, present at relatively high concentrations in the propolis. Considering that the chemical composition and, consequently, the biological activity of propolis is variable according to the environmental plant ecology, the present study was conducted in order to evaluate the radioprotective capacity of Brazilian propolis, collected in the State of Rio Grande do Sul, against genotoxic damages induced by {sup 60}Co {gamma}-radiation in Chinese hamster ovary cells (CHO-K1). for this purpose, micronucleus induction was analyzed concerning irreparable damage, specifically related to DNA double-strand breaks, that are potentially carcinogenic. CHO-K1 cells were submitted to different concentrations of propolis (3 - 33 {mu}g/ml), 1 h before irradiation, with 1 Gy of {gamma} radiation (0.722 Gy/min). The data obtained showed a decreasing tendency in the quantity of radioinduced damage on cells previously treated with propolis. The radioprotective effect was more prominent at higher propolis concentration. The treatment with propolis alone did not induce genotoxic effects on CHO-K1 cells. Beside that, the treatment with propolis, associated or not with radiation, did not influence the kinetics of cellular proliferation. (author)

  7. Molecular structural analysis of HPRT mutations induced by thermal and epithermal neutrons in Chinese hamster ovary cells.

    Science.gov (United States)

    Kinashi, Y; Sakurai, Y; Masunaga, S; Suzuki, M; Takagaki, M; Akaboshi, M; Ono, K

    2000-09-01

    Chinese hamster ovary (CHO) cells were exposed to thermal and epithermal neutrons, and the occurrence of mutations at the HPRT locus was investigated. The Kyoto University Research Reactor (KUR), which has been improved for use in neutron capture therapy, was the neutron source. Neutron energy spectra ranging from nearly pure thermal to epithermal can be chosen using the spectrum shifters and thermal neutron filters. To determine mutant frequency and cell survival, cells were irradiated with thermal and epithermal neutrons under three conditions: thermal neutron mode, mixed mode with thermal and epithermal neutrons, and epithermal neutron mode. The mutagenicity was different among the three irradiation modes, with the epithermal neutrons showing a mutation frequency about 5-fold that of the thermal neutrons and about 1.5-fold that of the mixed mode. In the thermal neutron and mixed mode, boron did not significantly increase the frequency of the mutants at the same dose. Therefore, the effect of boron as used in boron neutron capture therapy (BNCT) is quantitatively minimal in terms of mutation induction. Over 300 independent neutron-induced mutant clones were isolated from 12 experiments. The molecular structure of HPRT mutations was determined by analysis of all nine exons by multiplex polymerase chain reaction. In the thermal neutron and mixed modes, total and partial deletions were dominant and the fraction of total deletions was increased in the presence of boron. In the epithermal neutron mode, more than half of the mutations observed were total deletions. Our results suggest that there are clear differences between thermal and epithermal neutron beams in their mutagenicity and in the structural pattern of the mutants that they induce. Mapping of deletion breakpoints of 173 partial-deletion mutants showed that regions of introns 3-4, 7/8-9 and 9-0 are sensitive to the induction of mutants by neutron irradiation.

  8. Designing and Screening of Microsatellite Primers in Chinese Hamster%中国地鼠微卫星DNA引物的设计及筛选

    Institute of Scientific and Technical Information of China (English)

    宋国华; 耿佳宁; 贾若愚; 岳文斌; 刘田福; 胡松年

    2012-01-01

    本研究旨在筛选中国地鼠微卫星位点,为中国地鼠遗传分析提供遗传标记.根据建立的中国地鼠微卫星富集文库,对筛选的含微卫星DNA序列的克隆应用引物设计软件Primer 3.0设计引物135对,选择合成11对理论上易出现影子带的引物,用20个中国地鼠个体对这些引物进行了评估.结果显示,11对引物均能扩增出谱带,这11条带的平均多态信息含量(PIC)为0.4195,平均观察杂合度(Ho)为0.3895,平均期望杂合度(He)为0.4565,每个位点的平均等位基因数为5.818.筛选出的微卫星位点均可用于中国地鼠种群遗传结构分析,这将为中国地鼠品种选育、种系评估提供更多的微卫星遗传标记信息.%The objectives of the present study were to screen new microsatellite loci in Chinese hamster to develop genetic markers for genetic analysis. A library of partial small size fractionated genomic DNA was constructed with the Chinese hamster. 135 pairs of primers were designed with the software Primer 3. 0 for rnicrosatellites positive clones obtained. 11 pairs primers that the stutter bands easily in theory were synthesized and 20 samples were tested with them. The results showed 10 of the 11 loci were found to be polymorphic,and PIC, the mean observed heterozygosities (Ho) , the mean expected heterozy-gosities( He) were 0. 4195, 0. 3895 and 0. 4565, respectively. The microsatellite markers would be useful for further studying on accessions identification and breeding of Chinese hamster,which would provide some evaluable tools for marker-assisted selection breeding and gene mapping in Chinese hamster.

  9. Lack of Bystander Effects From High LET Radiation For Early Cytogenetic Endpoints.

    Energy Technology Data Exchange (ETDEWEB)

    Groesser, Torsten; Cooper, Brian; Rydberg, Bjorn

    2008-05-07

    The aim of this work was to study radiation-induced bystander effects for early cytogenetic end points in various cell lines using the medium transfer technique after exposure to high- and low-LET radiation. Cells were exposed to 20 MeV/ nucleon nitrogen ions, 968 MeV/nucleon iron ions, or 575 MeV/nucleon iron ions followed by transfer of the conditioned medium from the irradiated cells to unirradiated test cells. The effects studied included DNA double-strand break induction, {gamma}-H2AX focus formation, induction of chromatid breaks in prematurely condensed chromosomes, and micronucleus formation using DNA repair-proficient and -deficient hamster and human cell lines (xrs6, V79, SW48, MO59K and MO59J). Cell survival was also measured in SW48 bystander cells using X rays. Although it was occasionally possible to detect an increase in chromatid break levels using nitrogen ions and to see a higher number of {gamma}-H2AX foci using nitrogen and iron ions in xrs6 bystander cells in single experiments, the results were not reproducible. After we pooled all the data, we could not verify a significant bystander effect for any of these end points. Also, we did not detect a significant bystander effect for DSB induction or micronucleus formation in these cell lines or for clonogenic survival in SW48 cells. The data suggest that DNA damage and cytogenetic changes are not induced in bystander cells. In contrast, data in the literature show pronounced bystander effects in a variety of cell lines, including clonogenic survival in SW48 cells and induction of chromatid breaks and micronuclei in hamster cells. To reconcile these conflicting data, it is possible that the epigenetic status of the specific cell line or the precise culture conditions and medium supplements, such as serum, may be critical for inducing bystander effects.

  10. Short hairpin RNA targeted to dihydrofolate reductase enhances the immunoglobulin G expression in gene-amplified stable Chinese hamster ovary cells.

    Science.gov (United States)

    Wu, Suh-Chin; Hong, Willy W L; Liu, Jin-Hwang

    2008-09-08

    The dihydrofolate reductase (dhfr)/methotrexate (MTX) selection is a common method to conduct gene amplification in stable clones of Chinese hamster ovary (CHO) cells. We previously reported the use of a short hairpin RNA (shRNA) vector targeted to the dhfr gene resulted in improving the intracellular antigen expression in gene-amplified stable CHO cells [Hong, W.W., Wu, S.C., 2007. A novel RNA silencing vector to improve antigen expression and stability in Chinese hamster ovary cells. Vaccine 25 (20), 4103-4111]. Here we investigated the use of the dhfr-targeted shRNA vector for immunoglobulin G (IgG) expression in gene-amplified stable CHO cells. With the use of the dhfr-targeted shRNA vector, the gene-amplified CHO/dhFr(-) cells were found to increase IgG expression at 1.0 microM MTX by more than 100% and to improve the genomic stability of IgG expression in MTX-free cultures by approximately 30%. The use of the dhfr-targeted shRNA vector can enhance the IgG expression in the gene-amplified stable CHO cells and uphold the IgG expression in MTX-free cultures. Utilizing the dhfr-targeted shRNA vector may provide an alternative way to maneuver CHO cell factories for IgG production in cultures.

  11. Protective Effect of Boric Acid on Oxidative DNA Damage In Chinese Hamster Lung Fibroblast V79 Cell Lines

    Directory of Open Access Journals (Sweden)

    SezenYılmaz

    2016-02-01

    Full Text Available Objective: Many studies have been published on the antioxidative effects of boric acid (BA and sodium borates in in vitro studies. However, the boron (B concentrations tested in these in vitro studies have not been selected by taking into account the realistic blood B concentrations in humans due to the lack of comprehensive epidemiological studies. The recently published epidemiological studies on B exposure conducted in China and Turkey provided blood B concentrations for both humans in daily life and workers under extreme exposure conditions in occupational setting. The results of these studies have made it possible to test antioxidative effects of BA in in vitro studies within the concentration range relevant to humans. The aim of this study was to investigate the protective effects of BA against oxidative DNA damage in V79 (Chinese hamster lung fibroblast cells. The concentrations of BA tested for its protective effect was selected by taking the blood B concentrations into account reported in previously published epidemiological studies. Therefore, the concentrations of BA tested in this study represent the exposure levels for humans in both daily life and occupational settings. Materials and Methods: In this experimental study, comet assay and neutral red uptake (NRU assay methods were used to determinacy to toxicity and genotoxicity of BA and hydrogen peroxide (H2O2. Results: The results of the NRU assay showed that BA was not cytotoxic within the tested concentrations (3, 10, 30, 100 and 200 μM. These non-cytotoxic concentrations were used for comet assay. BA pre-treatment significantly reduced (P<0.05, one-way ANOVA the DNA damaging capacity of H2O2 at each tested BA concentrations in V79 cells. Conclusion: Consequently, pre-incubation of V79 cells with BA has significantly reduced the H2O2-induced oxidative DNA damage in V79 cells. The protective effect of BA against oxidative DNA damage in V79 cells at 5, 10, 50, 100 and 200 μM (54

  12. Establishment and Identification of Chinese Hamster Ovary Cell Lines with Stable Expression of Soluble CD40 Ligands

    Directory of Open Access Journals (Sweden)

    JIANG Hua-wei

    2014-09-01

    Full Text Available Objective: To establish the Chinese Hamster Ovary (CHO cell lines with stable expression of soluble CD40 ligands (sCD40L. Methods: Recombinant plasmid pIRES2-EGFP-sCD40L, enzyme digestion and sequencing identification were obtained by cloning sCD40L coding sequences into eukaryotic expression vector pIRES2-EGFP from carrier pDC316-sCD40 containing sCD40L. CHO cells were transfected by electroporation, followed by screening of resistant clones with G418, after which monoclones were obtained by limited dilution assay and multiply cultured. Flow cytometer and reverted fluorescence microscope were applied to observe the expression of green fluorescent protein, while sCD40L expression was detected by polymerase chain reaction (PCR, reverse transcription-polymerase chain reaction (RT-PCR and enzyme-linked immunosorbent assay (ELISA from aspects of deoxyribose nucleic acid (DNA, messenger ribonucleic acid (mRNA and protein, respectively. CHO-sCD40L was cultured together with MDA-MB-231 cells to compare the expression changes of surface molecule fatty acid synthase (Fas by flow cytometer and observe the apoptosis of MDA-MB-231 cells after Fas activated antibodies (CH-11 were added 24 h later. Results: Plasmid pIRES2-EGFP-sCD40L was successfully established, and cell lines with stable expression of sCD40L were obtained with cloned culture after CHO cell transfection, which was named as B11. Flow cytometer and reverted fluorescence microscope showed >90% expression of green fluorescent protein, while PCR, RT-PCR and ELISA suggested integration of sCD40L genes into cell genome DNA, transcription of sCD40L mRNA and sCD40L protein expression being (4.5±2.1 ng/mL in the supernatant of cell culture, respectively. After co-culture of B11 and MDA-MB-231 cells, the surface Fas expression of MDA-MB-231 cells was increased from (3±1.02 % to (34.8±8.75%, while the apoptosis rate 24 h after addition of CH11 from (5.4±1.32% to (20.7±5.24%, and the differences

  13. Intracellular Transactivation of Epidermal Growth Factor Receptor by alpha(1A)-Adrenoceptor Is Mediated by Phosphatidylinositol 3-Kinase Independently of Activation of Extracellular Signal Regulated Kinases 1/2 and Serine-Threonine Kinases in Chinese Hamster Ovary Cells

    NARCIS (Netherlands)

    Ulu, Nadir; Henning, Robert H.; Guner, Sahika; Zoto, Teuta; Duman-Dalkilic, Basak; Duin, Marry; Gurdal, Hakan

    2013-01-01

    Transactivation of epidermal growth factor receptor (EGFR) by alpha(1)-adrenoceptor (alpha(1)-AR) is implicated in contraction and hypertrophy of vascular smooth muscle (VSM). We examine whether all alpha(1)-AR subtypes transactivate EGFR and explore the mechanism of transactivation. Chinese hamster

  14. Test for Chemical Induction of Chromosome Aberrations in Cultured Chinese Hamster Ovary (CHO) Cells with and without Metabolic Activation, Test Article: 3-Nitro-1,2,4-Triazol-5-one (NTO)

    Science.gov (United States)

    2008-10-30

    3110 Dicentric - an asymmetrical exchange between two chromosomes resulting in a chromosome with two centromeres with or without an accompanying...chromatid union. Dicentric - an asymmetrical exchange between two chromosomes resulting in a chromosome with two centromeres with or without an...Test for Chemical fuduction of Chromosome Aberrations in Cultured Chinese Hamster Ovary (CHO) Cells With and Without Metabolic Activation Test

  15. Bystanders Are the Key to Stopping Bullying

    Science.gov (United States)

    Padgett, Sharon; Notar, Charles E.

    2013-01-01

    Bullying is the dominance over another. Bullying occurs when there is an audience. Peer bystanders provide an audience 85% of instances of bullying. If you remove the audience bullying should stop. The article is a review of literature (2002-2013) on the role of bystanders; importance of bystanders; why bystanders behave as they do; resources to…

  16. Relationship between tissue plasminogen activator production and specific growth rate in Chinese hamster ovary cells cultured in mannose at low temperature.

    Science.gov (United States)

    Berrios, Julio; Díaz-Barrera, Alvaro; Bazán, Consuelo; Altamirano, Claudia

    2009-10-01

    Chinese hamster ovary (CHO) cells, producing human recombinant tissue plasminogen activator (tPA), were grown with mannose (5, 20 and 40 mM) instead of glucose at 31, 33 and 37 degrees C. The highest tPA concentration (1.5 mg l(-1) at 144 h of cultivation) and tPA specific production rate (47 ng 10(-6) cell h(-1)) were obtained at 31 degrees C and 40 mM mannose. Regardless of the temperature or mannose concentration used, an inverse relationship between the specific growth rate and tPA specific production rate was observed, suggesting that tPA production rate would be directly controlled by the growth rate.

  17. In vivo mutagenicity studies in rats mice and Chinese hamsters fed irradiated foodstuffs - chicken, fish, dates, pulses, mangoes and cocoa beans

    Energy Technology Data Exchange (ETDEWEB)

    Renner, H.W.

    1982-11-01

    Three in vivo genetic toxicity tests were performed in rats, mice and Chinese hamsters to detect possible mutagenic effects of irradiated chicken, dried dates, fish, cocoa beans, pulses and mangoes. The tests employed were the micronucleus test and sister-chromatid exchange (SCE) test for irradiated and unirradiated samples of all foodstuffs listed, and the spermatogonia test, (including SCE technique) in mice for irradiated and unirradiated chicken, fish and dates only. In the case of cocoa beans, the mutagenicity tests were performed on an additional test group fed beans fumigated with ethylene oxide. The different mammalian species used for the various experiments are given below. None of the tests provided any evidence of mutagenicity induced by irradiation in any of the foodstuffs studied. Moreover, these tests are currently considered to be the most sensitive in vivo mutagenicity tests in mammals.

  18. Toxicology Studies on Lewisite and Sulfur Mustard Agents: Genetic Toxicity of Sulfur Mustard (HD) in Chinese Hamster Ovary Cells Final Report

    Energy Technology Data Exchange (ETDEWEB)

    Jostes, Jr., R. F.; Sasser, L. B.; Rausch, R. J.

    1989-05-01

    The cytotoxic, clastogenic and mutagenic effects of sulfur nustard in Chinese hamster ovary cells are described in this reoort. The cytotoxicity data indicate that micromolar amounts of HC are highly toxic in microrolar amounts. Chromosone aberration frequencies increased in a dose-dependent manner over a dose range of 0. 5 to 1.0 {micro}m and SCE increased in a dose-dependent fashion in the dose range of 0.0625 to 0.25 {micro}M. Mutation induction at the HGPRT locus was sporadic, but the majority of the exoosures resulted in mutation frequencies which were 1.2 to 4.3 fold higher than the spontaneous frequencies.

  19. Culture of Population Inbreed Line of Chinese hamster in Shanxi Medical University%中国地鼠山医群体近交系的培育

    Institute of Scientific and Technical Information of China (English)

    刘田福

    2003-01-01

    @@ 中国地鼠(Chinese hamster)是黑线仓鼠(Cricetulus barabensis Pallas)的俗称.原产于中国,分布在河北、北京、辽宁、山东、山西、河南、安徽和江苏等地.身体被毛,背部、尾基部背面和四条腿背面的毛为灰褐色、土黄色或黄褐色(毛基部黑色,毛尖褐色),自耳基部到尾部前端的背中央有一条很细的纵行黑毛(从毛根到毛尖全黑),背脊好像隐约有一条黑线故名黑线仓鼠.

  20. Human delta opioid receptor: functional studies on stably transfected Chinese hamster ovary cells after acute and chronic treatment with the selective nonpeptidic agonist SNC-80.

    Science.gov (United States)

    Malatynska, E; Wang, Y; Knapp, R J; Waite, S; Calderon, S; Rice, K; Hruby, V J; Yamamura, H I; Roeske, W R

    1996-09-01

    The SNC-80 series of nonpeptidic agonists for the delta-opioid receptor are being developed as potential analgesic drugs. It is important to understand their acute and chronic effects at human delta-opioid receptors. Thus, we measured the ability of SNC-80 and [D-Pen2,4'-Cl-Phe4,D-Pen5]enkephalin to inhibit forskolin-stimulated adenylyl cyclase activity in recombinant Chinese hamster ovary cells stably expressing the cloned human delta-opioid receptor. The calculated EC50 values for [D-Pen2,4'-Cl-Phe4,D-Pen5]enkephalin and SNC-80 were 0.6 +/- 0.1 nM and 6.3 +/- 0.1 nM, respectively. Pretreatment of these cells with SNC-80 (100 nM) for 24 hr produced 1) a time-dependent reduction of delta receptor density, as measured by radioligand binding studies with [3H]naltrindole; 2) a shift in the EC50 value of SNC-80 from 7.7 +/- 4.2 nM to 44.1 +/- 12 nM, as measured by the cyclic AMP assay; 3) a reduction in the maximum inhibition of adenylyl cyclase activity from 86% to 48%; 4) a marked increase in the forskolin stimulation of basal cyclic AMP accumulation by nearly 100% (from 442 pmol/mg of protein to 824 pmol/mg of protein); and 5) a 5-fold increase in forskolin-stimulated cyclic AMP accumulation after addition of naltrindole. These studies showed that SNC-80 produced desensitization and down-regulation of human delta-opioid receptors in recombinant Chinese hamster ovary cells after chronic treatment and that this effect was associated with an increase in adenylyl cyclase activity.

  1. Biological characteristics of Chinese hamster infected with Babesia%巴贝西虫感染黑线仓鼠生物学特性的变化

    Institute of Scientific and Technical Information of China (English)

    叶莉; 白杰英; 马帅; 王昱佳; 郑珺文; 王冬平; 李桂军; 范君文; 时彦胜; 张小飞

    2016-01-01

    Objective To establish a Chinese hamster model of babesia infection, to find the changing pattern of organs and biochemical parameters in Chinese hamster infected with Babesia, and to promote the detection and treatment of babesiosis.Methods Healthy 5-week old Chinese hamsters were infected by intraperitoneal injection of blood containing Babesia.Blood samples were collected at 0, 2, 4, 6, 8, 10, 12, 14, 16, 23, 30, and 37 days after infection from 5 hamsters at each time point.Blood smears were prepared to detect the parasites using Giemsa staining.ELISA assay was employed to test the IL-2 concentration.The blood biochemical indexes were detected using an automatic biochemical analyzer.DNA was extracted from the whole blood and REAL-TIME RCR was performed to determine the reproduction of Babesia.Aftert the animals were sacrificed, the heart, lung, spleen, liver, and kidney were taken to analyze the changes of organ coefficients.Results The highest level of Babesia in the hamsters occurred on day 4 after the Babesia injection, and then showing a decreasing tendency.However, there was a transient increase on the 12th day after infection.The liver and spleen displayed most extensive response to the infection showing hepatomegaly and splenomegaly, but the variation of heart and kidneys coefficients was within the norm.There were prominent changes of blood cells, especially leucocytes, with two peaks at day 10 and 23 after the Babesia infection.The peak changes of blood biochemical indexes occurred at day 12 after infection.The concentration of serum IL-2 reached a peak on the 10th day after infection.Conclusions The Chinese hamsters display typical characteristics of tick-borne diseases such as hepatomegaly and splenomegaly.The immunological system is activated along with the infection and reaches a highest stage in the second week.Afterwards the Babesia can live in the hamster body for a long period of time.The results of this study provide useful information

  2. Metabolism of radiohafnium in marmosets and hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Taylor, D.M.; Seidel, A.; Doerfel, H.

    1985-01-01

    The whole body retention of /sup 181/Hf was studied in marmosets (Callithrex jacchus) and found to be closely similar to that in rats and Chinese hamsters. Limited tissue distribution studies suggest a higher uptake in liver and much lower deposition in skin and muscle in the marmoset as compared to the rat or Chinese hamster. Studies in Chinese hamsters showed that treatment with the chelating agent diethylenetriaminepentaacetic acid resulted in only a small reduction in the whole body retention of /sup 181/Hf. The absorption of orally administered /sup 181/Hf, in various chemical forms, was found to be between 0.04 and 0.13% of the ingested dose and was unaffected by age between 5 and 21 months but was increased by fasting. The measured absorption of /sup 181/Hf in Chinese hamsters and in rats was similar to that of plutonium suggesting that radiohafnium could be used as a surrogate for plutonium for selected studies in human volunteers.

  3. Bystander effect-induced mutagenicity in HPRT locus of CHO cells following BNCT neutron irradiation: Characteristics of point mutations by sequence analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kinashi, Yuko [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka (Japan)], E-mail: kinashi@rri.kyoto-u.ac.jp; Suzuki, Minoru; Masunaga, Shinichiro; Ono, Koji [Research Reactor Institute, Kyoto University, Kumatori-cho, Sennan-gun, Osaka (Japan)

    2009-07-15

    To investigate bystander mutagenic effects induced by alpha particles during boron neutron capture therapy (BNCT), we mixed cells that were electroporated with borocaptate sodium (BSH), which led to the accumulation of {sup 10}B inside the cells, with cells that did not contain the boron compound. BSH-containing cells were irradiated with {alpha} particles produced by the {sup 10}B(n,{alpha}){sup 7}Li reaction, whereas cells without boron were only affected by the {sup 1}H(n,{gamma}){sup 2}H and {sup 14}N(n,{rho}){sup 14}C reactions. The frequency of mutations induced in the hypoxanthine-guanine phosphoribosyltransferase (HPRT) locus was examined in Chinese hamster ovary (CHO) cells irradiated with neutrons (Kyoto University Research Reactor: 5 MW). Neutron irradiation of 1:1 mixtures of cells with and without BSH resulted in a survival fraction of 0.1, and the cells that did not contain BSH made up 99.4% of the surviving cell population. Using multiplex polymerase chain reactions (PCRs), molecular structural analysis indicated that most of the mutations induced by the bystander effect were point mutations and that the frequencies of total and partial deletions induced by the bystander effect were lower than those resulting from the {alpha} particles produced by the {sup 10}B(n,{alpha}){sup 7}Li reaction or the neutron beam from the {sup 1}H(n,{gamma}){sup 2}H and {sup 14}N(n,{rho}){sup 14}C reactions. The types of point mutations induced by the BNCT bystander effect were analyzed by cloning and sequencing methods. These mutations were comprised of 65.5% base substitutions, 27.5% deletions, and 7.0% insertions. Sequence analysis of base substitutions showed that transversions and transitions occurred in 64.7% and 35.3% of cases, respectively. G:C{yields}T:A transversion induced by 8-oxo-guanine in DNA occurred in 5.9% of base substitution mutants in the BNCT bystander group. The characteristic mutations seen in this group, induced by BNCT {alpha} particles

  4. Test for Chemical Induction of Chromosome Aberration in Cultured Chinese Hamster Ovary (CHO) Cells With and Without Metabolic Activation. Test Article: N,N,N’,N’-tetramethyl Ethanediamine (TMEDA)

    Science.gov (United States)

    2008-06-13

    union. d Dicentric - an asymmetrical exchange between two chromosomes resulting in a chromosome with two centromeres with or without an accompanying...Test for Chemical Induction of Chromosome Aberrations in Cultured Chinese Hamster Ovary (CHO) Cells With and Without Metabolic Activation Test...number. 1. REPORT DATE 26 JUN 2008 2. REPORT TYPE 3. DATES COVERED 4. TITLE AND SUBTITLE Test for Chemical Induction of Chromosome

  5. Construction and identification of DNA libraries enriched for microsatellite repeat sequences of Chinese hamster%中国地鼠基因组微卫星富集文库的构建与分析

    Institute of Scientific and Technical Information of China (English)

    宋国华; 耿佳宁; 贾若愚; 岳文斌; 刘田福; 胡松年

    2011-01-01

    目的 筛选中国地鼠微卫星位点,为中国地鼠种质资源的分类、进化等遗传研究奠定基础.方法中国地鼠基因组DNA经超声打碎,用2%琼脂糖凝胶电泳回收500~1000 bp的DNA片段,与SNX连接头连接,连接产物与生物素标记的14种微卫星探针变性及退火,再通过链亲和素偶联磁珠亲和捕捉,经吸附、洗涤及洗脱,然后以洗脱产物为模板,通过PCR扩增,与pGEM-T载体连接,转化大肠杆菌DH10B,构建中国地鼠微卫星DNA富集文库.结果 测序结果发现,微卫星DNA序列的阳性克隆占70.3%.结论 中国地鼠微卫星文库的建立和微卫星的筛选将为下一步进行中国地鼠遗传连锁图谱的构建、分子进化和系统发育研究提供大量的微卫星标记.%Objective To screen the microsatellite loci of Chinese hamster DNA to serve the genetic studies of germplasm resources, classification and evolution of Chinese hamsters. Methods Genomic DNAs from Chinese hamster was fragmented by ultrasonication. The fragments in size from 500 bp to 1000 bp were recovered by 2% agarose gel electro-phoresis and ligated to SNX linkers with T4 DNA ligase, then denatured and hybridized to 14 biotinylated oligonucleotides. The biotinylated hybrids were retained on magnetic beads according to the strong afinity between biotin and streptavidin. The products was amplified by PCR and cloned into pGEM-T plasmid vector, and then transformed into Escherichia coli DH10B to construct DNA libraries enriched for microsatellite repeat sequences of Chinese hamster. Results The results of sequencing showed that sequences contained microsatellites indicating a high degree of microsatellite enrichment. Conclusions The new polymorphic microsatellite markers identified and characterized in this study may serve the Chinese hamster genetic linkage mapping, molecular evolution and phylogenetic studies.

  6. A fucan from the brown seaweed Spatoglossum schröederi inhibits Chinese hamster ovary cell adhesion to several extracellular matrix proteins

    Directory of Open Access Journals (Sweden)

    H.A.O. Rocha

    2001-05-01

    Full Text Available Fucans, a family of sulfated polysaccharides present in brown seaweed, have several biological activities. Their use as drugs would offer the advantage of no potential risk of contamination with viruses or particles such as prions. A fucan prepared from Spatoglossum schröederi was tested as a possible inhibitor of cell-matrix interactions using wild-type Chinese hamster ovary cells (CHO-K1 and the mutant type deficient in xylosyltransferase (CHO-745. The effect of this polymer on adhesion properties with specific extracellular matrix components was studied using several matrix proteins as substrates for cell attachment. Treatment with the polymer inhibited the adhesion of fibronectin to both CHO-K1 (2 x 10(5(and CHO-745 (2 x 10(5 and 5 x 10(5 cells. No effect was detected with laminin, using the two cell types. On the other hand, adhesion to vitronectin was inhibited in CHO-K1 cells and adhesion to type I collagen was inhibited in CHO-745 cells. In spite of this inhibition, the fucan did not affect either cell proliferation or cell cycle. These results demonstrate that this polymer is a new anti-adhesive compound with potential pharmacological applications.

  7. A fucan from the brown seaweed Spatoglossum schröederi inhibits Chinese hamster ovary cell adhesion to several extracellular matrix proteins.

    Science.gov (United States)

    Rocha, H A; Franco, C R; Trindade, E S; Carvalho, L C; Veiga, S S; Leite, E L; Dietrich, C P; Nader, H B

    2001-05-01

    Fucans, a family of sulfated polysaccharides present in brown seaweed, have several biological activities. Their use as drugs would offer the advantage of no potential risk of contamination with viruses or particles such as prions. A fucan prepared from Spatoglossum schröederi was tested as a possible inhibitor of cell-matrix interactions using wild-type Chinese hamster ovary cells (CHO-K1) and the mutant type deficient in xylosyltransferase (CHO-745). The effect of this polymer on adhesion properties with specific extracellular matrix components was studied using several matrix proteins as substrates for cell attachment. Treatment with the polymer inhibited the adhesion of fibronectin to both CHO-K1 (2 x 10(5)) and CHO-745 (2 x 10(5) and 5 x 10(5)) cells. No effect was detected with laminin, using the two cell types. On the other hand, adhesion to vitronectin was inhibited in CHO-K1 cells and adhesion to type I collagen was inhibited in CHO-745 cells. In spite of this inhibition, the fucan did not affect either cell proliferation or cell cycle. These results demonstrate that this polymer is a new anti-adhesive compound with potential pharmacological applications.

  8. Effect of PD 128763, a new potent inhibitor of poly(ADP-ribose) polymerase, on X-ray-induced cellular recovery processes in Chinese hamster V79 cells

    Energy Technology Data Exchange (ETDEWEB)

    Arundel-Suto, C.M.; Scavone, S.V.; Turner, W.R.; Suto, M.J.; Sebolt-Leopold, J.S. (Warner-Lambert Company, Ann Arbor, MI (USA))

    1991-06-01

    The modifying effects of PD 128763 (3,4-dihydro-5-methyl-1(2H)-isoquinolinone), a potent inhibitor of poly(adenosine-diphosphate (ADP)-ribose) polymerase, on radiation-induced cell killing were examined in Chinese hamster V79 cells. This compound has an IC50 value against the purified enzyme approximately 50X lower than 3-aminobenzamide (3-AB), a widely used specific inhibitor of the enzyme. Exposure of exponentially growing cells to a noncytotoxic concentration (0.5 mM) of PD 128763 for 2 h immediately following X irradiation increased their radiation sensitivity, modifying both the shoulder and the slope of the survival curve. When recovery from sublethal damage and potentially lethal damage was examined in exponential and plateau-phase cells, respectively, postirradiation incubation with 0.5 mM PD 128763 was found not only to inhibit both these processes fully, but also to enhance further the level of radiation-induced cell killing. This is in contrast to the slight effect seen with the less potent inhibitor, 3-AB. The results presented suggest that the mechanism of radiosensitization by PD 128763 is related to the potent inhibition of poly(ADP-ribose) polymerase by this compound.

  9. High zinc ion supplementation of more than 30 μM can increase monoclonal antibody production in recombinant Chinese hamster ovary DG44 cell culture.

    Science.gov (United States)

    Kim, Bong Gyun; Park, Hong Woo

    2016-03-01

    Effects of high ZnSO4·7H2O supplementation on cell growth and monoclonal antibody (mAb) production in chemically defined suspension cultures of recombinant Chinese hamster ovary (rCHO) DG44 cells were examined. The supplementation of ZnSO4·7H2O up to 120 μM gradually increased specific mAb production rate of rCHO DG44 cells in the early growth phase (0-4 days of culture). The ZnSO4·7H2O concentration for enhancing mAb production without any cytotoxic effects on cell growth was 30-60 μM. In addition of 60 μM ZnSO4·7H2O to in-house protein-free medium and in-house chemically defined medium, mAb production was increased 2.0-fold and 6.5-fold, respectively. Moreover, addition of ZnSO4·7H2O to three kinds of commercial chemically defined media yielded a greater than 1.2-fold enhancement of mAb production. These data indicate that simple supplementation of a relatively high zinc ion concentration to cell culture media without significant changes of rCHO DG44 cell culture process can be useful for achieving high production of mAb.

  10. Comparative study of the cytotoxic and genotoxic effects of titanium oxide and aluminium oxide nanoparticles in Chinese hamster ovary (CHO-K1) cells.

    Science.gov (United States)

    Di Virgilio, A L; Reigosa, M; Arnal, P M; Fernández Lorenzo de Mele, M

    2010-05-15

    The aim of this study was to analyze the cytotoxicity and genotoxicity of titanium oxide (TiO(2)) and aluminium oxide (Al(2)O(3)) nanoparticles (NPs) on Chinese hamster ovary (CHO-K1) cells using neutral red (NR), mitochondrial activity (by MTT assay), sister chromatid exchange (SCE), micronucleus (MN) formation, and cell cycle kinetics techniques. Results showed a dose-related cytotoxic effect evidenced after 24h by changes in lysosomal and mitochondrial dehydrogenase activity. Interestingly, transmission electronic microscopy (TEM) showed the formation of perinuclear vesicles in CHO-K1 cells after treatment with both NPs during 24h but no NP was detected in the nuclei. Genotoxic effects were shown by MN frequencies which significantly increased at 0.5 and 1 microg/mL TiO(2) and 0.5-10 microg/mL Al(2)O(3). SCE frequencies were higher for cells treated with 1-5 microg/mL TiO(2). The absence of metaphases evidenced cytotoxicity for higher concentrations of TiO(2). No SCE induction was achieved after treatment with 1-25 microg/mL Al(2)O(3). In conclusion, findings showed cytotoxic and genotoxic effects of TiO(2) and Al(2)O(3) NPs on CHO-K1 cells. Possible causes of controversial reports are discussed further on.

  11. Sustained productivity in recombinant Chinese Hamster Ovary (CHO) cell lines: proteome analysis of the molecular basis for a process-related phenotype

    LENUS (Irish Health Repository)

    Meleady, Paula

    2011-07-24

    Abstract Background The ability of mammalian cell lines to sustain cell specific productivity (Qp) over the full duration of bioprocess culture is a highly desirable phenotype, but the molecular basis for sustainable productivity has not been previously investigated in detail. In order to identify proteins that may be associated with a sustained productivity phenotype, we have conducted a proteomic profiling analysis of two matched pairs of monoclonal antibody-producing Chinese hamster ovary (CHO) cell lines that differ in their ability to sustain productivity over a 10 day fed-batch culture. Results Proteomic profiling of inherent differences between the two sets of comparators using 2D-DIGE (Difference Gel Electrophoresis) and LC-MS\\/MS resulted in the identification of 89 distinct differentially expressed proteins. Overlap comparisons between the two sets of cell line pairs identified 12 proteins (AKRIB8, ANXA1, ANXA4, EIF3I, G6PD, HSPA8, HSP90B1, HSPD1, NUDC, PGAM1, RUVBL1 and CNN3) that were differentially expressed in the same direction. Conclusion These proteins may have an important role in sustaining high productivity of recombinant protein over the duration of a fed-batch bioprocess culture. It is possible that many of these proteins could be useful for future approaches to successfully manipulate or engineer CHO cells in order to sustain productivity of recombinant protein.

  12. Engineering the cellular protein secretory pathway for enhancement of recombinant tissue plasminogen activator expression in Chinese hamster ovary cells: effects of CERT and XBP1s genes.

    Science.gov (United States)

    Rahimpour, Azam; Vaziri, Behrouz; Moazzami, Reza; Nematollahi, Leila; Barkhordari, Farzaneh; Kokabee, Leila; Adeli, Ahmad; Mahboudi, Fereidoun

    2013-08-01

    Cell line development is the most critical and also the most time-consuming step in the production of recombinant therapeutic proteins. In this regard, a variety of vector and cell engineering strategies have been developed for generating high-producing mammalian cells; however, the cell line engineering approach seems to show various results on different recombinant protein producer cells. In order to improve the secretory capacity of a recombinant tissue plasminogen activator (t-PA)-producing Chinese hamster ovary (CHO) cell line, we developed cell line engineering approaches based on the ceramide transfer protein (CERT) and X-box binding protein 1 (XBP1) genes. For this purpose, CERT S132A, a mutant form of CERT that is resistant to phosphorylation, and XBP1s were overexpressed in a recombinant t-PA-producing CHO cell line. Overexpression of CERT S132A increased the specific productivity of t-PA-producing CHO cells up to 35%. In contrast, the heterologous expression of XBP1s did not affect the t-PA expression rate. Our results suggest that CERTS132A- based secretion engineering could be an effective strategy for enhancing recombinant t- PA production in CHO cells.

  13. The effects of captan and captafol on different bacterial strains and on c-mitosis in V79 Chinese hamster fibroblasts.

    Science.gov (United States)

    Rahden-Staroń, I; Szumiło, M; Ziemkiewicz, P

    1994-01-01

    The mutagenic activity of captan and captafol was tested using Ames strains and strains showing an SOS response. Captafol was mutagenic in S. typhimurium strain TA102 (uvr+) and captan in strain TA104 (uvrB). Both captan and captafol elicit damages in DNA recognized by correndonuclease II, as shown by the repair test, and induced the SOS repair system in E. coli PQ37 (uvrA) strain. Only captafol induced the SOS system in PQ35 (uvr+). The lack of induction of beta-galactosidase at nonpermissive temperature in E. coli MD332 (dnaCs uvrA) strain showed that neither chemical was able to produce DNA breaks. In V79 Chinese hamster fibroblasts higher induction of c-mitosis by captafol than by captan (22% and 15% over the control, respectively) was accompanied by a higher decrease in nonprotein sulfhydryl groups, mainly GSH (41% and 77%, respectively). The content of protein sulfhydryl groups was decreased by either fungicide to a similar extent.

  14. Contribution to the validation of the anaphase-telophase test: aneugenic and clastogenic effects of cadmium sulfate, potassium dichromate and nickel chloride in Chinese hamster ovary cells

    Directory of Open Access Journals (Sweden)

    Seoane A.I.

    1999-01-01

    Full Text Available There is increasing evidence that aneuploidy during mitosis may be a factor in the etiology of somatic malignancy. The analysis of alterations in anaphase-telophase of mitosis is a useful test for evaluating the aneuploidogenic and clastogenic ability of chemicals. Several metals have been found to be carcinogenic to humans and animals. However, the underlying mechanisms remain unclear. In the present study the aneugenic and clastogenic abilities of cadmium sulfate, potassium dichromate and nickel chloride were analyzed using the anaphase-telophase test. Chinese hamster ovary (CHO cells cultured for two cycles were treated with the desired compound for 8 h before cell harvesting. The frequency of cells with chromatin bridges, lagging chromosomes and lagging chromosomal fragments was scored. The mitotic index was determined by counting the number of mitotic cells per 1,000 cells on each coverslip and was expressed as a percentage of the number of mitotic plates. Statistical comparisons were done using the "G" method. Correlation and regression analyses were performed to evaluate variations of the mitotic index. Chromium and cadmium were clastogenic and aneugenic and increased the frequencies of the three types of aberrations scored; nickel had only aneugenic activity because it increased the frequency of lagging chromosomes. These results indicate that the anaphase-telophase test is sufficiently sensitive to detect dose-response relationships that can distinguish clastogenic and/or aneugenic activities and that the results obtained using the anaphase-telophase test were similar to those obtained by chromosome counting.

  15. Effect of oxygen-radiosensitizer mixtures on the radiation response of Chinese hamster cells, line V-79-753B, in vitro

    Energy Technology Data Exchange (ETDEWEB)

    Millar, B.C.; Fielden, E.M.; Steele, J.J.

    1980-07-01

    The present data show that the maximum yield of single-strand breaks (ssb) in the cellular DNA of Chinese hamster cells V-79-753B is produced at a concentration of oxygen that produces an enhancement ratio for cell survival of 1.9. The relationship between the oxygen concentration and enhancement ratio for survival in this cell line is biphasic with a plateau at ER = 1.9 over the range of 1.5 to 7 ..mu..M O/sub 2/. For concetrations of oxygen below 1.5 ..mu..M a linear relationship between 1/D/sub 0/ and the initial yield of ssb is found. Electron affinic and free radical radiosensitizers operate by different mechanisms which are reflected at the level of ssb production; electron affinic compounds increase the yield of ssb in anoxia and in the presence of low concentrations of oxygen, whereas free radical radiosensitizers do not. The observation that TMPN can compete with oxygen or misonidazole in reactions that lead to changes in radiosensitivity but not ssb production indicates that the relationship between the two parameters must be casual and not casual.

  16. Generation of high-producing cell lines by overexpression of cell division cycle 25 homolog A in Chinese hamster ovary cells.

    Science.gov (United States)

    Lee, Kyoung Ho; Tsutsui, Tomomi; Honda, Kohsuke; Asano, Ryutaro; Kumagai, Izumi; Ohtake, Hisao; Omasa, Takeshi

    2013-12-01

    To improve the efficiency of conventional gene amplification systems, the effect of cell cycle modification during the gene amplification process on IgG production was investigated in Chinese hamster ovary (CHO) cells. The full-length cDNA of CHO cell division cycle 25 homolog A (Cdc25A) was introduced into CHO DG44 cells and the effects of CDC25A overexpression on the cell cycle, transgene copy number and IgG productivity were examined. Both wild-type and mutated CDC25A-overexpressing CHO cells showed a rapid increase in transgene copy number compared with mock cells during the gene amplification process, in both cell pools and individual clones. High-producing clones were obtained with high frequency in CDC25A-overexpressing cell pools. The specific production rate of the isolated clone CHO SD-S23 was up to 2.9-fold higher than that of mock cells in the presence of 250 nM methotrexate (MTX). Cell cycle analysis revealed that the G2 to M phase transition rate was increased ∼1.5-fold in CDC25A-overexpressing CHO cells under MTX treatment. Our results show the improvement of conventional gene amplification systems via cell cycle engineering at an early stage of cell line development.

  17. Improved gene amplification by cell-cycle engineering combined with the Cre-loxP system in Chinese hamster ovary cells.

    Science.gov (United States)

    Matsuyama, Rima; Tsutsui, Tomomi; Lee, Kyoung Ho; Onitsuka, Masayoshi; Omasa, Takeshi

    2015-12-01

    The dihydrofolate reductase gene amplification system is widely used in Chinese hamster ovary (CHO) cells for the industrial production of therapeutic proteins. To enhance the efficiency of conventional gene amplification systems, we previously presented a novel method using cell-cycle checkpoint engineering. Here, we constructed high-producing and stable cells by the conditional expression of mutant cell division cycle 25 homolog B (CDC25B) using the Cre-loxP system. A bispecific antibody-producing CHO DG44-derived cell line was transfected with floxed mutant CDC25B. After inducing gene amplification in the presence of 250 nM methotrexate, mutant CDC25B sequence was removed by Cre recombinase protein expression. Overexpression of the floxed mutant CDC25B significantly enhanced the efficiency of transgene amplification and productivity. Moreover, the specific production rate of the isolated clone CHO Cre-1 and Cre-2 were approximately 11-fold and 15-fold higher than that of mock-transfected clone CHO Mock-S. Chromosomal aneuploidy was increased by mutant CDC25B overexpression, but Cre-1 and Cre-2 did not show any changes in chromosome number during long-term cultivation, as is the case with CHO Mock-S. Our results suggest that high-producing and stable cells can be constructed by conditionally controlling a cell-cycle checkpoint integrated in conventional gene amplification systems.

  18. Cytogenetic response to 1,2-dicarbonyls and hydrogen peroxide in Chinese hamster ovary AUXB1 cells and human peripheral lymphocytes.

    Science.gov (United States)

    Tucker, J D; Taylor, R T; Christensen, M L; Strout, C L; Hanna, M L; Carrano, A V

    1989-10-01

    Mutagenic 1,2-dicarbonyls have been reported to occur in coffee and other beverages and in various foods. We have measured the induction of sister-chromatid exchanges (SCEs) and endoreduplicated cells (ERCs) to determine the genotoxicity of various 1,2-dicarbonyl compounds in Chinese hamster ovary (CHO) AUXB1 cells and human peripheral lymphocytes. The 1,2-dicarbonyls glyoxal, methylglyoxal and kethoxal each induced highly significant increases in both SCEs and ERCs in AUXB1 cells. Glyoxal and kethoxal induced SCEs but not ERCs in human peripheral lymphocytes. In addition, hydrogen peroxide induced highly significant levels of SCEs and ERCs in AUXB1 cells. Bisulfite, which reacts with carbonyl groups to form addition products, significantly reduced the frequency of SCEs and the proportion of ERCs when glyoxal, methylglyoxal, kethoxal and diacetyl were administered to AUXB1 cells. In addition, bisulfite blocked the formation of ERCs, but not SCEs, induced by hydrogen peroxide. These in vitro results suggest that 1,2-dicarbonyls may play an important role in the genotoxicity of some foods and beverages.

  19. Monitoring utilizations of amino acids and vitamins in culture media and Chinese hamster ovary cells by liquid chromatography tandem mass spectrometry.

    Science.gov (United States)

    Qiu, Jinshu; Chan, Pik Kay; Bondarenko, Pavel V

    2016-01-01

    Monitoring amino acids and vitamins is important for understanding human health, food nutrition and the culture of mammalian cells used to produce therapeutic proteins in biotechnology. A method including ion pairing reversed-phase liquid chromatography with tandem mass spectrometry was developed and optimized to quantify 21 amino acids and 9 water-soluble vitamins in Chinese hamster ovary (CHO) cells and culture media. By optimizing the chromatographic separation, scan time, monitoring time window, and sample preparation procedure, and using isotopically labeled (13)C, (15)N and (2)H internal standards, low limits of quantitation (≤0.054 mg/L), good precision (amino acids showed a zigzag pattern with maxima at the feeding days, and 9 non-essential amino acids displayed a smoothly changing profile as they were mainly products of cellular metabolism. Five of 9 vitamins accumulated continuously during the culture period, suggesting that they were fed in access. The method serves as an effective tool for the development and optimization of mammalian cell cultures.

  20. Effect of temperature shift on levels of acidic charge variants in IgG monoclonal antibodies in Chinese hamster ovary cell culture.

    Science.gov (United States)

    Kishishita, Shohei; Nishikawa, Tomoko; Shinoda, Yasuharu; Nagashima, Hiroaki; Okamoto, Hiroshi; Takuma, Shinya; Aoyagi, Hideki

    2015-06-01

    During the production of therapeutic monoclonal antibodies (mAbs), not only enhancement of mAb productivity but also control of quality attributes is critical. Charge variants, which are among the most important quality attributes, can substantially affect the in vitro and in vivo properties of mAbs. During process development for the production of mAbs in a Chinese hamster ovary cell line, we have observed that an improvement in mAb titer is accompanied by an increase in the content of acidic charge variants. Here, to help maintain comparability among mAbs, we aimed to identify the process parameters that controlled the content of acidic charge variants. First, we used a Plackett-Burman design to identify the effect of selected process parameters on the acidic charge variant content. Eight process parameters were selected by using a failure modes and effects analysis. Among these, temperature shift was identified from the Plackett-Burman design as the factor most influencing the acidic charge variant content. We then investigated in more detail the effects of shift temperature and temperature shift timing on this content. The content decreased with a shift to a lower temperature and with earlier timing of this temperature shift. Our observations suggest that Plackett-Burman designs are advantageous for preliminary screening of bioprocess parameters. We report here for the first time that temperature downshift is beneficial for effective control of the acidic peak variant content.

  1. Chromium(VI)—induces Production of Reactive Oxygen Species,Change of Plasma Membrane Potential and Dissipation of Mitochondria Membrane otential in Chinese Hamster Lung Cell Cultures

    Institute of Scientific and Technical Information of China (English)

    XIEYI; ZHUANGZHI-XIONG

    2001-01-01

    Objective:To examine whether Reactive Oxygen Species(ROS) is generated,and whether plasma membrane potential and mitochnodrial membrane potential are depolarized in Chinese Hamster Lung(CHL)cell lines exposed to Cr(VI),Methods:CHL Cells were incubated with Cr(VI) at 10 umol/L,2.5umol/L,0.65umol/L for 3 and 6 hours,respectively.The rpoduction of ROS was performed by using 2,7-dichlorofluorescin discetate;The changes in plasma membrane potential were performed by using 2,7-dichlorofluorescin discetate;The changes in plasma membrane potential were performed by using 2,7-dichlorofluorescin diacetate;The changes in plasma membrane potential were estimated using fluorescent cationic dye DiBAC4;And the changes in mitochondria membrane potential were estimated using fluorescent dye Rhodamine 123,Results:The ROS levels in CHL cells increased in all treated groups compared with the control group(P<0.01);The plasma membrane potential and mitochondrial membrane potential in CHL cells dissipated after incubated with Cr(VI) at 10umol/L for 3 hours and 6 hours(P<0.01),at 2.5umol/L for 6 hours(P<0.01 or 0.05),Conclusion:Cr(VI) causes the dissipation of plasma membrane potential and mitochnodrial membrane otential in CHL cell cultrues,and Cr(VI)-induced ROS may play a role in the injuries.

  2. Chromium(VI)-induced Production of Reactive Oxygen Species, Change of Plasma Membrane Potential and Dissipation of Mitochondria Membrane Potential in Chinese Hamster Lung Cell Cultures

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Objective To examine whether Reactive Oxygen Species (ROS) is generated, and whether plasma membrane potential and mitochondrial membrane potential are depolarized in Chinese Hamster Lung (CHL) cell lines exposed to Cr (VI). Methods CHL cells were incubated with Cr(VI) at 10 μmol/L, 2.5 μmol/L, 0.65 μmol/L for 3 and 6 hours, respectively. The production of ROS was performed by using 2,7_dichlorofluorescin diacetate; The changes in plasma membrane potential were estimated using fluorescent cationic dye DiBAC4; And the changes in mitochondria membrane potential were estimated using fluorescent dye Rhodamine 123. Results The ROS levels in CHL cells increased in all treated groups compared with the control group (P<0.01); The plasma membrane potential and mitochondrial membrane potential in CHL cells dissipated after incubated with Cr(VI) at 10 μmol/L for 3 hours and 6 hours (P<0.01), at 2.5 μmol/L for 6 hours (P<0.01 or 0.05). Conclusion Cr(VI) causes the dissipation of plasma membrane potential and mitochondrial membrane potential in CHL cell cultures, and Cr(VI)_induced ROS may play a role in the injuries.

  3. A novel regulatory element (E77) isolated from CHO-K1 genomic DNA enhances stable gene expression in Chinese hamster ovary cells.

    Science.gov (United States)

    Kang, Shin-Young; Kim, Yeon-Gu; Kang, Seunghee; Lee, Hong Weon; Lee, Eun Gyo

    2016-05-01

    Vectors flanked by regulatory DNA elements have been used to generate stable cell lines with high productivity and transgene stability; however, regulatory elements in Chinese hamster ovary (CHO) cells, which are the most widely used mammalian cells in biopharmaceutical production, are still poorly understood. We isolated a novel gene regulatory element from CHO-K1 cells, designated E77, which was found to enhance the stable expression of a transgene. A genomic library was constructed by combining CHO-K1 genomic DNA fragments with a CMV promoter-driven GFP expression vector, and the E77 element was isolated by screening. The incorporation of the E77 regulatory element resulted in the generation of an increased number of clones with high expression, thereby enhancing the expression level of the transgene in the stable transfectant cell pool. Interestingly, the E77 element was found to consist of two distinct fragments derived from different locations in the CHO genome shotgun sequence. High and stable transgene expression was obtained in transfected CHO cells by combining these fragments. Additionally, the function of E77 was found to be dependent on its site of insertion and specific orientation in the vector construct. Our findings demonstrate that stable gene expression mediated by the CMV promoter in CHO cells may be improved by the isolated novel gene regulatory element E77 identified in the present study.

  4. Moral Disengagement Among Bystanders to School Bullying

    DEFF Research Database (Denmark)

    Obermann, Marie-Louise

    2011-01-01

    This study examined the use of moral disengagement among children indirectly involved in bullying (bystanders). A sample of Danish adolescents (N = 660, M age 12.6 years) were divided into four groups depending on their bystander status: (a) outsiders, who did not experience bullying among...... their peers; (b) defenders, who were likely to help the victims in bullying episodes; (c) guilty bystanders, who did nothing to help bullied peers but felt guilty about it; and (d) unconcerned bystanders, who witnessed peers being bullied, without feeling responsible. Results indicated that, besides from...... active personal involvement in bullying others, being an unconcerned bystander to bullying also associates with moral disengagement. Unconcerned bystanders had significantly higher moral disengagement than guilty bystanders and defenders. Outsiders also showed significant higher disengagement than...

  5. Bystander Effects of Ionizing Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Little, John B. [Harvard T.H. Chan School of Public Health, Boston, MA (United States). Dept. of Genetics and Complex Diseases

    2017-01-17

    The objectives of this grant renewal are to provide administrative support and travel funds to allow the continued participation of the principal investigator (Dr. John B. Little) as an advisor to research initiated by several research fellows from his laboratory. The actual research will be carried out under the direction of Dr. Hatsumi Nagasawa with the collaboration of Dr. Joel Bedford at the Colorado State University, and by Drs. Edouard Azzam and Sonia de Toledo at the University of Medicine and Dentistry of New Jersey. Dr. Little will advise on the planning of experiments and development of experimental protocols, the analysis of data, and the preparation of manuscripts for publication. The Specific Aims for several of the planned experiments include: 1) to extend studies of the role of recombinational repair in the bystander effect by examining other genes in this pathway and cell lines deficient in excision repair; 2) to continue studies to determine the nature of the damage signal transmitted to bystander cells including the expression of several connexins in the bystander response, and the extent to which the enhanced oxidative metabolism observed in bystander cells may relate to the nature of the transmitted bystander signal; 3) to utilize a genome-wide approach to examine the genetic basis for the hypersensitivity to ionization we have observed in unaffected parents of patients with hereditary retinoblastoma, as well as from a group of a apparently normal individuals that show similar radiosensitivity; 4) to complete studies concerning the induction of high frequencies of cells with massive chromosome damage in clonal derivatives of p53 and p21 knockout mouse cell lines; in particular to examine the role of telomere changes in this phenomenon. Overall, the results of these studies should enhance our understanding of the risk of low dose exposures to ionizing radiation, including human populations to residential radon as well as occupational exposures.

  6. Comparison of the carbohydrate moieties of recombinant soluble Fc epsilon receptor (sFc epsilon RII/sCD23) expressed in Saccharomyces cerevisiae and Chinese hamster ovary cells. Different O-glycosylation sites are used by yeast and mammalian cells.

    Science.gov (United States)

    Kalsner, I; Schneider, F J; Geyer, R; Ahorn, H; Maurer-Fogy, I

    1992-08-01

    Recombinant human soluble low affinity receptor for the Fc portion of IgE (sFc epsilon RII/sCD23) was produced in Saccharomyces cerevisiae or Chinese hamster ovary cells and subjected to carbohydrate analysis. Applied methods included analytical SDS-PAGE, reversed phase HPLC, methylation analysis and sequential degradation with exoglycosidases. The results revealed that sFc epsilon RII derived from Chinese hamster ovary cells is glycosylated exclusively at Ser-147, containing mainly the trisaccharide Sia(alpha 2-3)Gal(beta 1-3)GalNAc, whereas the yeast derived glycoprotein was glycosylated at Ser-167 and contained only alpha-mannosyl residues. It is shown here for the first time that different amino acids of a given protein can be O-glycosylated when expressed in yeast or Chinese hamster ovary cells.

  7. Feature gene selection for Chinese hamster classification based on support vector machine%基于支持向量机的中国地鼠分类特征基因选取

    Institute of Scientific and Technical Information of China (English)

    杨俊丽; 刘田福

    2011-01-01

    针对中国地鼠基因表达谱数据维数高和样本小的特点,提出一种基于支持向量机(SVM)的分类特征基因选取方法.该方法利用改进的Fisher判别(FDR)基因特征计分准则剔除分类无关基因,提出由空间距离和功能距离组成的新距离作为相似性度量的标准进行冗余基因的剔除,采用SVM作为分类器检验特征基因的分类性能.实验结果表明,该方法有效地剔除了分类无关基因和冗余基因,选取的特征基因满足对中国地鼠正确分类的最小基因数.%Concerning the gene expression profile of Chinese hamster feature, such as high-dimension and small sample,a method of feature selection for Chinese hamster classification based on Support Vector Machine (SVM) was proposed in this paper. The method used improved FDR gene feature score criterion to remove the genes irrelevant to the classification. A new distance composed by space distance and function distance was proposed as the criterion of comparability to remove redundant genes. A SVM was used as classifier to validate the classification performance of the feature genes selected. The experimental results show that this method effectively removes the irrelevant and redundant genes, and selected the feature genes that meet the needs of least feature genes which classify accurately on Chinese hamster.

  8. Comparative study of the cytotoxic and genotoxic effects of titanium oxide and aluminium oxide nanoparticles in Chinese hamster ovary (CHO-K1) cells

    Energy Technology Data Exchange (ETDEWEB)

    Di Virgilio, A.L. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Diag. 113 y 64, Correo 16, Suc. 4, La Plata (1900) (Argentina); Reigosa, M. [Instituto Multidisciplinario de Biologia Celular (IMBICE), Calle 526 y Camino Gral. Belgrano (entre 10 y 11), La Plata 1900 (Argentina); Arnal, P.M. [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Diag. 113 y 64, Correo 16, Suc. 4, La Plata 1900 (Argentina); Fernandez Lorenzo de Mele, M., E-mail: mmele@inifta.unlp.edu.ar [Instituto de Investigaciones Fisicoquimicas Teoricas y Aplicadas (INIFTA), Diag. 113 y 64, Correo 16, Suc. 4, La Plata 1900 (Argentina)

    2010-05-15

    The aim of this study was to analyze the cytotoxicity and genotoxicity of titanium oxide (TiO{sub 2}) and aluminium oxide (Al{sub 2}O{sub 3}) nanoparticles (NPs) on Chinese hamster ovary (CHO-K1) cells using neutral red (NR), mitochondrial activity (by MTT assay), sister chromatid exchange (SCE), micronucleus (MN) formation, and cell cycle kinetics techniques. Results showed a dose-related cytotoxic effect evidenced after 24 h by changes in lysosomal and mitochondrial dehydrogenase activity. Interestingly, transmission electronic microscopy (TEM) showed the formation of perinuclear vesicles in CHO-K1 cells after treatment with both NPs during 24 h but no NP was detected in the nuclei. Genotoxic effects were shown by MN frequencies which significantly increased at 0.5 and 1 {mu}g/mL TiO{sub 2} and 0.5-10 {mu}g/mL Al{sub 2}O{sub 3}. SCE frequencies were higher for cells treated with 1-5 {mu}g/mL TiO{sub 2}. The absence of metaphases evidenced cytotoxicity for higher concentrations of TiO{sub 2}. No SCE induction was achieved after treatment with 1-25 {mu}g/mL Al{sub 2}O{sub 3}. In conclusion, findings showed cytotoxic and genotoxic effects of TiO{sub 2} and Al{sub 2}O{sub 3} NPs on CHO-K1 cells. Possible causes of controversial reports are discussed further on.

  9. Changes in the Number of Double-Strand DNA Breaks in Chinese Hamster V79 Cells Exposed to γ-Radiation with Different Dose Rates

    Directory of Open Access Journals (Sweden)

    Andreyan N. Osipov

    2013-07-01

    Full Text Available A comparative investigation of the induction of double-strand DNA breaks (DSBs in the Chinese hamster V79 cells by γ-radiation at dose rates of 1, 10 and 400 mGy/min (doses ranged from 0.36 to 4.32 Gy was performed. The acute radiation exposure at a dose rate of 400 mGy/min resulted in the linear dose-dependent increase of the γ-H2AX foci formation. The dose-response curve for the acute exposure was well described by a linear function y = 1.22 + 19.7x, where “y” is an average number of γ-H2AX foci per a cell and “x” is the absorbed dose (Gy. The dose rate reduction down to 10 mGy/min lead to a decreased number of γ-H2AX foci, as well as to a change of the dose-response relationship. Thus, the foci number up to 1.44 Gy increased and reached the “plateau” area between 1.44 and 4.32 Gy. There was only a slight increase of the γ-H2AX foci number (up to 7 in cells after the protracted exposure (up to 72 h to ionizing radiation at a dose rate of 1 mGy/min. Similar effects of the varying dose rates were obtained when DNA damage was assessed using the comet assay. In general, our results show that the reduction of the radiation dose rate resulted in a significant decrease of DSBs per cell per an absorbed dose.

  10. Effect of Temperature Downshift on the Transcriptomic Responses of Chinese Hamster Ovary Cells Using Recombinant Human Tissue Plasminogen Activator Production Culture.

    Science.gov (United States)

    Bedoya-López, Andrea; Estrada, Karel; Sanchez-Flores, Alejandro; Ramírez, Octavio T; Altamirano, Claudia; Segovia, Lorenzo; Miranda-Ríos, Juan; Trujillo-Roldán, Mauricio A; Valdez-Cruz, Norma A

    2016-01-01

    Recombinant proteins are widely used as biopharmaceuticals, but their production by mammalian cell culture is expensive. Hence, improvement of bioprocess productivity is greatly needed. A temperature downshift (TDS) from 37°C to 28-34°C is an effective strategy to expand the productive life period of cells and increase their productivity (qp). Here, TDS in Chinese hamster ovary (CHO) cell cultures, initially grown at 37°C and switched to 30°C during the exponential growth phase, resulted in a 1.6-fold increase in the qp of recombinant human tissue plasminogen activator (rh-tPA). The transcriptomic response using next-generation sequencing (NGS) was assessed to characterize the cellular behavior associated with TDS. A total of 416 (q > 0.8) and 3,472 (q > 0.9) differentially expressed transcripts, with more than a 1.6-fold change at 24 and 48 h post TDS, respectively, were observed in cultures with TDS compared to those at constant 37°C. In agreement with the extended cell survival resulting from TDS, transcripts related to cell growth arrest that controlled cell proliferation without the activation of the DNA damage response, were differentially expressed. Most upregulated genes were related to energy metabolism in mitochondria, mitochondrial biogenesis, central metabolism, and avoidance of apoptotic cell death. The gene coding for rh-tPA was not differentially expressed, but fluctuations were detected in the transcripts encoding proteins involved in the secretory machinery, particularly in glycosylation. Through NGS the dynamic processes caused by TDS were assessed in this biological system.

  11. Multiplex polymerase chain reaction analysis of UV-A- and UV-B-induced delayed and early mutations in V79 Chinese hamster cells.

    Science.gov (United States)

    Dahle, Jostein; Noordhuis, Paul; Stokke, Trond; Svendsrud, Debbie Hege; Kvam, Egil

    2005-01-01

    We previously reported that approximately 10% of V79 Chinese hamster fibroblast populations clonally derived from single cells immediately after irradiation with either ultraviolet B (UV-B, 290-320 nm, mainly 311 nm) or ultraviolet A (UV-A, 320-400 nm, mainly 350-390 nm) radiation exhibit genomic instability. The instability is revealed by relatively high mutation frequencies in the hypoxanthine phosphoribosyl transferase (hprt) gene up to 23 cell generations after irradiation. These delayed mutant clones exhibited higher levels of oxidative stress than normal cells. Therefore, persistently increased oxidative stress has been proposed as a mechanism for UV-induced genomic instability. This study investigates whether this mechanism is reflected in the deletion spectrum of delayed mutant clones. Eighty-eight percent of the delayed mutant clones derived from UV-A-irradiated populations were found to have total deletion of the hprt gene. Correspondingly, 81% of UV-A-induced early mutations (i.e. detected shortly after irradiation) also had total deletions. Among delayed UV-B-induced mutant clones, 23% had total deletions and 8% had deletion of one exon, whereas all early UV-B events were either point mutations or small deletions or insertions. In conclusion, the multiplex polymerase chain reaction deletion screen showed that there were explicit differences in the occurrence of large gene alterations between early and delayed mutations induced by UV-B radiation. For UV-A radiation the deletion spectra were similar for delayed and early mutations. UV-A radiation is, in contrast to UV-B radiation, only weakly absorbed by DNA and probably induces mutation almost solely via production of reactive oxygen species. Therefore, the present results support the hypothesis that persistent increase in oxidative stress is involved in the mechanism of UV-induced genomic instability.

  12. Understanding of altered N-glycosylation-related gene expression in recombinant Chinese hamster ovary cells subjected to elevated ammonium concentration by digital mRNA counting.

    Science.gov (United States)

    Ha, Tae Kwang; Kim, Yeon-Gu; Lee, Gyun Min

    2015-08-01

    To understand the effects of ammonium on N-glycosylation, recombinant Chinese hamster ovary (rCHO) cells that produce the Fc-fusion protein were cultivated in serum-free suspension cultures with 10 mM ammonium addition. The addition of ammonium to the cultures reduced the relative proportion of acidic isoforms and sialic acid content of an Fc-fusion protein. Fifty two N-glycosylation-related gene expressions were assessed by the NanoString nCounter system, which provides a digital readout using custom-designed color-coded probes. Among these queried genes, thirteen genes (gale, nans, gpi, man2a1, b4galt5, b4galt7, st3gal2, st3gal5, glb1, hexa, hexb, neu1, and neu3) were up-regulated over 1.5 times in the culture with ammonium addition after 5 days of culture; however, none of the 54 genes were significantly different after 3 days of culture. In particular, the expression level of neu1 (sialidase-1) and neu3 (sialidase-3), which play a role in reduction of sialylation, increased over 2 times. Likewise, the protein expression levels of sialidase-1 and sialidase-3 determined by Western blot analysis were also increased significantly in the culture with ammonium addition. Transient transfection of neu-1 or neu3-targeted siRNAs significantly improved the sialic acid content of the Fc-fusion protein in the culture with ammonium addition, indicating that the decreased sialic acid content was in part due to the increased expression level of sialidase. Taken together, the results obtained in this study provide a better understanding of the detrimental effect of ammonium on N-glycosylation, especially sialylation, in rCHO cells.

  13. Molecular polygamy: The promiscuity of l-phenylalanyl-tRNA-synthetase triggers misincorporation of meta- and ortho-tyrosine in monoclonal antibodies expressed by Chinese hamster ovary cells.

    Science.gov (United States)

    Popp, Oliver; Larraillet, Vincent; Kettenberger, Hubert; Gorr, Ingo H; Hilger, Maximiliane; Lipsmeier, Florian; Zeck, Anne; Beaucamp, Nicola

    2015-06-01

    In-depth analytical characterization of biotherapeutics originating from different production batches is mandatory to ensure product safety and consistent molecule efficacy. Previously, we have shown unintended incorporation of tyrosine (Tyr) and leucine/isoleucine (Leu/Ile) at phenylalanine (Phe) positions in a recombinant produced monoclonal antibody (mAb) using an orthogonal MASCOT/SIEVE based approach for mass spectrometry data analysis. The misincorporation could be avoided by sufficient supply of phenylalanine throughout the process. Several non-annotated signals in the primarily chromatographic peptide separation step for apparently single Phe→Tyr sequence variants (SVs) suggest a role for isobar tyrosine isoforms. Meta- and ortho-Tyr are spontaneously generated during aerobic fed-batch production processes using Chinese hamster ovary (CHO) cell lines. Process induced meta- and ortho-Tyr but not proteinogenic para-Tyr are incorporated at Phe locations in Phe-starved CHO cultures expressing a recombinant mAb. Furthermore, meta- and ortho-Tyr are preferably misincorporated over Leu. Structural modeling of the l-phenylalanyl-tRNA-synthetase (PheRS) substrate activation site indicates a possible fit of non-cognate ortho-Tyr and meta-Tyr substrates. Dose-dependent misincorporations of Tyr isoforms support the hypothesis that meta- and ortho-Tyr are competing, alternative substrates for PheRS in CHO processes. Finally, easily accessible at-line surrogate markers for Phe→Tyr SV formation in biotherapeutic production were defined by the calculation of critical ratios for meta-Tyr/Phe and ortho-Tyr/Phe to support early prediction of SV probability, and finally, to allow for immediate process controlled Phe→Tyr SV prevention.

  14. The impact of homologous recombination repair deficiency on depleted uranium clastogenicity in Chinese hamster ovary cells: XRCC3 protects cells from chromosome aberrations, but increases chromosome fragmentation

    Energy Technology Data Exchange (ETDEWEB)

    Holmes, Amie L. [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Department of Applied Medical Science, University of Southern Maine, 96 Falmouth Street, P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Joyce, Kellie [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Xie, Hong [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Department of Applied Medical Science, University of Southern Maine, 96 Falmouth Street, P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Falank, Carolyne [Wise Laboratory of Environmental and Genetic Toxicology, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); Maine Center for Toxicology and Environmental Health, University of Southern Maine, 96 Falmouth St., P.O. Box 9300, Portland, ME 04104-9300, United States of America (United States); and others

    2014-04-15

    Highlights: • The role of homologous recombination repair in DU-induced toxicity was examined. • Loss of RAD51D did not affect DU-induced cytotoxicity or genotoxicity. • XRCC3 protects cell from DU-induced chromosome breaks and fusions. • XRCC3 plays a role in DU-induced chromosome fragmentation of the X chromosome. - Abstract: Depleted uranium (DU) is extensively used in both industry and military applications. The potential for civilian and military personnel exposure to DU is rising, but there are limited data on the potential health hazards of DU exposure. Previous laboratory research indicates DU is a potential carcinogen, but epidemiological studies remain inconclusive. DU is genotoxic, inducing DNA double strand breaks, chromosome damage and mutations, but the mechanisms of genotoxicity or repair pathways involved in protecting cells against DU-induced damage remain unknown. The purpose of this study was to investigate the effects of homologous recombination repair deficiency on DU-induced genotoxicity using RAD51D and XRCC3-deficient Chinese hamster ovary (CHO) cell lines. Cells deficient in XRCC3 (irs1SF) exhibited similar cytotoxicity after DU exposure compared to wild-type (AA8) and XRCC3-complemented (1SFwt8) cells, but DU induced more break-type and fusion-type lesions in XRCC3-deficient cells compared to wild-type and XRCC3-complemented cells. Surprisingly, loss of RAD51D did not affect DU-induced cytotoxicity or genotoxicity. DU induced selective X-chromosome fragmentation irrespective of RAD51D status, but loss of XRCC3 nearly eliminated fragmentation observed after DU exposure in wild-type and XRCC3-complemented cells. Thus, XRCC3, but not RAD51D, protects cells from DU-induced breaks and fusions and also plays a role in DU-induced chromosome fragmentation.

  15. Cell killing, nuclear damage and apoptosis in Chinese hamster V79 cells after irradiation with heavy-ion beams of (16)O, (12)C and (7)Li.

    Science.gov (United States)

    Pathak, Rupak; Dey, Subrata Kumar; Sarma, Asiti; Khuda-Bukhsh, Anisur Rahman

    2007-08-15

    Chinese hamster V79 cells were exposed to high LET (linear energy transfer) (16)O-beam (625keV/mum) radiation in the dose range of 0-9.83Gy. Cell survival, micronuclei (MN), chromosomal aberrations (CA) and induction of apoptosis were studied as a follow up of our earlier study on high LET radiations ((7)Li-beam of 60keV/mum and (12)C-beam of 295keV/mum) as well as (60)Co gamma-rays. Dose dependent decline in surviving fraction was noticed along with the increase of MN frequency, CA frequency as well as percentage of apoptosis as detected by nuclear fragmentation assay. The relative intensity of DNA ladder, which is a useful marker for the determination of the extent of apoptosis induction, was also increased in a dose dependent manner. Additionally, expression of tyrosine kinase lck-1 gene, which plays an important role in response to ionizing radiation induced apoptosis, was increased with the increase of radiation doses and also with incubation time. The present study showed that all the high LET radiations were generally more effective in cell killing and inflicting other cytogenetic damages than that of low LET gamma-rays. The dose response curves revealed that (7)Li-beam was most effective in cell killing as well as inducing other nuclear damages followed by (12)C, (16)O and (60)Co gamma-rays, in that order. The result of this study may have some application in biological dosimetry for assessment of genotoxicity in heavy ion exposed subjects and in determining suitable doses for radiotherapy in cancer patients where various species of heavy ions are now being generally used.

  16. Predicting the expression of recombinant monoclonal antibodies in Chinese hamster ovary cells based on sequence features of the CDR3 domain.

    Science.gov (United States)

    Pybus, Leon P; James, David C; Dean, Greg; Slidel, Tim; Hardman, Colin; Smith, Andrew; Daramola, Olalekan; Field, Ray

    2014-01-01

    Despite the development of high-titer bioprocesses capable of producing >10 g L(-1) of recombinant monoclonal antibody (MAb), some so called "difficult-to-express" (DTE) MAbs only reach much lower process titers. For widely utilized "platform" processes the only discrete variable is the protein coding sequence of the recombinant product. However, there has been little systematic study to identify the sequence parameters that affect expression. This information is vital, as it would allow us to rationally design genetic sequence and engineering strategies for optimal bioprocessing. We have therefore developed a new computational tool that enables prediction of MAb titer in Chinese hamster ovary (CHO) cells based on the recombinant coding sequence of the expressed MAb. Model construction utilized a panel of MAbs, which following a 10-day fed-batch transient production process varied in titer 5.6-fold, allowing analysis of the sequence features that impact expression over a range of high and low MAb productivity. The model identified 18 light chain (LC)-specific sequence features within complementarity determining region 3 (CDR3) capable of predicting MAb titer with a root mean square error of 0.585 relative expression units. Furthermore, we identify that CDR3 variation influences the rate of LC-HC dimerization during MAb synthesis, which could be exploited to improve the production of DTE MAb variants via increasing the transfected LC:HC gene ratio. Taken together these data suggest that engineering intervention strategies to improve the expression of DTE recombinant products can be rationally implemented based on an identification of the sequence motifs that render a recombinant product DTE.

  17. Follicle-stimulating Hormone (FSH) Induced Internalization of Porcine FSH Receptor in Cultured Porcine Granulosa Cells and Chinese Hamster Ovary Cells Transfected with Recombinant Porcine FSH Receptor cDNA

    Institute of Scientific and Technical Information of China (English)

    ZHU; Changhong; TIAN; Hong; XIONG; Zhongming; XIA; Huizhu

    2001-01-01

    In order to study the fate of human follicle-stimulating hormone (FSH) when hormone binds to its receptor, a quick biochemical method that can differentiate between the surface-bound and internalized hormone was used to determine the internalization induced by FSH in cultured both porcine granulosa cells and Chinese hamster ovary (CHO) cells expressing recombinant porcine FSH receptor. The results showed that FSH was slowly internalized, and the internalized radioactivity (acid resistant) reached a peak 10-12 h after addition of 125I-hFSH. It was suggested that FSHR do not get internalized rapidly under physiological circumstances precisely because the appropriate sequences are absent.

  18. 中国地鼠线粒体D-loop基因的克隆及序列分析%Cloning and Sequence Analysis of Mitochondrial D-loop Gene in Chinese Hamster

    Institute of Scientific and Technical Information of China (English)

    宋国华; 陈朝阳; 庞文彪; 高继萍; 岳文斌

    2013-01-01

    The primer was designed according to the closest animal published partial sequences, the PCR products were se-quenced and determined. Combined with the known D-loop region sequence of other rodents,nucleotide composition were analyzed with DNAStar and genetic distance was analyzed with MEGA 4. 1. The phylogenetic tree was constructed by neighbor-joining methods (NJ) and minimum-evolution methods (ME). The D-loop sequence of Chinese hamster had 867 bp, the nucleotide composition were relatively T(31. 49%) , C(26.07%), A(29.53%), and G(12. 92%). The different clustering methods all showed a similar result. Chinese hamsters had the closest relationship with golden hamsters, but had relatively large difference from mice and rats, basically consistent with the traditional taxonomic status. D-loop gene might be genetic marker among species. The results of this study might be of importance for studies on evolution, structure and function of the mitochondria in Chinese hamsters.%本试验根据已知相近物种动物基因序列设计引物,PCR扩增获得中国地鼠线粒体D-loop基因序列.采用DNAS-tar软件计算序列碱基组成,分析遗传变异情况.用MEGA 4.1软件计算物种间遗传距离,采用邻接法(NJ)、最小进化法(ME)构建系统进化树.结果表明,中国地鼠线粒体D-loop区序列全长为867 bp,碱基A、T、C、G的含量分别为29.53%、31.49%、26.07%、12.92%,中国地鼠与啮齿类动物有相似的碱基组成.系统进化树结果显示,中国地鼠与金黄地鼠亲缘关系较近,与大鼠的关系最远,与传统的分类相一致.所获得的中国地鼠D-loop基因可作为种间遗传变异研究的标记,研究结果为进一步研究中国地鼠的群体遗传结构奠定了基础.

  19. Moral Disengagement among Bystanders to School Bullying

    Science.gov (United States)

    Obermann, Marie-Louise

    2011-01-01

    This study examined the use of moral disengagement among children indirectly involved in bullying (bystanders). A sample of Danish adolescents (N = 660, M age 12.6 years) were divided into four groups depending on their bystander status: (a) outsiders, who did not experience bullying among their peers; (b) defenders, who were likely to help the…

  20. In vitro genotoxic and cytotoxic effects of ivermectin and its formulation ivomec on Chinese hamster ovary (CHO{sub K1}) cells

    Energy Technology Data Exchange (ETDEWEB)

    Molinari, G.; Soloneski, S.; Reigosa, M.A. [Catedra de Citologia, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata (Argentina); Larramendy, M.L., E-mail: m_larramendy@hotmail.com [Catedra de Citologia, Facultad de Ciencias Naturales y Museo, Universidad Nacional de La Plata, La Plata (Argentina)

    2009-06-15

    The effects of ivermectin (IVM) and its commercial formulation ivomec (IVM 1.0%) were studied on Chinese hamster ovary (CHO{sub K1}) cells by several genotoxicity [sister chromatid exchange (SCE) and single cell gel electrophoresis (SCGE)] and cytotoxicity [cell-cycle progression (CCP), mitotic index (MI), proliferative replication index (PRI), 3(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT), and neutral red (NR)] bioassays within the 1.0-250 {mu}g/ml concentration-range. While IVM and ivomec did not modified SCE frequencies, they induced DNA-strand breaks revealed by SCGE. An enhancement of slightly damaged cells and a decrease in undamaged cells were observed in IVM-treated cultures with 5.0-50.0 {mu}g/ml. In ivomec-treated cells, while an increase in slightly damaged cells was induced with 5.0-50.0 {mu}g/ml, the damaged and undamaged cells increased and decreased only with 50.0 {mu}g/ml. Both compounds exerted a delay in CCP and a reduction in PRI when 25.0 {mu}g/ml was employed whereas cytotoxicity was observed at higher concentration than 50.0 {mu}g/ml. No MI alteration was observed with 1.0-10.0 and 1.0-5.0 {mu}g/ml of IVM and ivomec, respectively. A concentration-related trend to an increase in MI was achieved within 1.0-10.0 {mu}g/ml. An increase in the MI was induced in 10.0 {mu}g/ml ivomec-treated cultures. A marked reduction of about 89% and 62% in regard to controls was observed with 25.0 {mu}g/ml of IVM and ivomec, respectively. NR and MTT assays revealed a cell growth inhibition when 0.25-250.0 {mu}g/ml of both compounds was employed. The results highlighted that IVM and ivomec exert both genotoxicity and cytotoxicity in mammalian cells in vitro, at least in CHO{sub K1} cells.

  1. Recombinant expression of human microsomal epoxide hydrolase protects V79 Chinese hamster cells from styrene oxide- but not from ethylene oxide-induced DNA strand breaks.

    Science.gov (United States)

    Herrero, M E; Arand, M; Hengstler, J G; Oesch, F

    1997-01-01

    Styrene 7,8-oxide and ethylene oxide are widely used genotoxic bulk chemicals, which have been associated with potential carcinogenic hazard for occupationally exposed workers. Both epoxides alkylate DNA preferentially at the N-7 position of guanine and consequently produce single-strand breaks and alkali labile sites in the DNA of exposed cells. In order to study the role of human microsomal epoxide hydrolase (hmEH) in protecting cells against genotoxicity of styrene 7,8-oxide and ethylene oxide, we expressed the cDNA of hmEH in V79 Chinese hamster cells. We obtained a number of cell clones that expressed functionally active epoxide hydrolase. Among these, the clone 92hmEH-V79 revealed an especially high enzymatic mEH activity toward styrene 7,8-oxide (10 nmol converted per mg of protein per min, measured in the 9,000 x g supernatant of the cell homogenate), that was 100 times higher than that determined in mock-transfected cells and within the range of mEH activity in human liver. Styrene 7,8-oxide-induced DNA single-strand breaks/alkali labile sites (dose range 10 microM to 1 mM styrene 7,8-oxide) measured by the alkaline elution technique were significantly lower in the 92hmEH-V79 cells as compared to the mock-transfected cells. The protection against styrene 7,8-oxide genotoxicity in 92hmEH-V79 cells could be abolished by addition of valpromide, a selective inhibitor of microsomal epoxide hydrolase. These results clearly show that the metabolism of styrene 7,8-oxide by hmEH in 92hmEH-V79 cells was responsible for the protection against styrene 7,8-oxide genotoxicity. On the other hand, no protective effect of epoxide hydrolase expression could be observed on ethylene oxide-induced DNA damage with the recombinant cell line over a dose range of 0.5-2.5 mM ethylene oxide. This selectivity of the protective effect on epoxide genotoxicity thus appears to be an important factor that must be taken into account for the prediction of the genotoxic risk of epoxides

  2. First genotoxicity study of Paraná river water from Argentina using cells from the clam Corbicula fluminea (Veneroida Corbiculidae and Chinese hamster (Cricetulus griseus Rodentia, Cricetidae K1 cells in the comet assay

    Directory of Open Access Journals (Sweden)

    Jacqueline D. Caffetti

    2008-01-01

    Full Text Available High concentrations of xenobiotics from urban and industrial wastes have contributed to the contamination of many aquatic environments. We used the comet assay to evaluate the genotoxic potential of water collected from the River Paraná, which receives a great deal of waste, at three points (Puerto Piray, Eldorado and Montecarlo in the Misiones Province of Argentina. The in vivo comet assay used 40 freshwater clams (Corbicula fluminea while the in vitro comet assay used Chinese hamster (Cricetulus griseus K1 cell (CHO-K1 cultures with the mutagen ethyl methanesulfonate (EMS as the positive control and phosphate buffered saline (PBS as the negative control. Both assays showed statistically significant differences between the three sampling sites in relation to the negative control, the results of this preliminary study indicating that at these three sites water from the Paraná River presents genotoxic potential.

  3. Effect of Ginsenoside Rd on Chromosome Aberration in Chinese Hamster Lung Cells%人参皂苷Rd对中国仓鼠肺细胞染色体畸变作用

    Institute of Scientific and Technical Information of China (English)

    高梅; 曹冲; 朱春花; 曲保恩

    2013-01-01

    目的 研究人参皂苷Rd致中国仓鼠肺细胞(Chinese hamster lung cells,CHL)染色体畸变的作用.方法 细胞计数法测定人参皂苷Rd对CHL细胞的半数抑制浓度(IC50),根据IC50设立不同剂量组,进行染色体畸变试验,分别观察人参皂苷Rd染毒6、24h及加S9后染毒6h CHL细胞染色体的数目及结构变化,进行染色体畸变分析.结果 人参皂苷Rd染毒6、24h及加S.后染毒6h CHL细胞染色体畸变为阴性.结论 在本试验条件下,人参皂苷Rd不能引起CHL细胞染色体产生畸变.%Objective To explore the effect of ginsenoside Rd on chromosome aberration in Chinese hamster lung cells(CHL). Methods We used the method of cell counting to determine the IC50, of ginsenoside Rd on CHL cells,then to establish the range of doses according to the IC50 and to do the cell chromosome aberration experiment. When the CHL cells were exposured to ginsenoside Rd at 6h and 24h and plused S9 mixture at 6h respectively, we observed the changes of chromosome number and structure, then to judge the chromosome aberration results. Results Negative response was found at 6h and 24h after the treatment with ginsenoside Rd and at 6h after the addition of S9 mixture. Conclusion Under the condition of this experiment, ginsenoside Rd does not induce chromosome aberration in CHL cells.

  4. Fluoride does not induce DNA breakage in Chinese hamster ovary cells in vitro Flúor não induz danos ao DNA em células de ovário de hamster chinês in vitro

    Directory of Open Access Journals (Sweden)

    Daniel Araki Ribeiro

    2004-09-01

    Full Text Available Fluoride has been widely used in dentistry because it is a specific and effective caries prophylactic agent. However, excess fluoride may represent a hazard to human health, especially by causing injury to genetic material. Genotoxicity tests represent an important part of cancer research to assess the risk of potential carcinogens. In the current study, the potential DNA damage associated with exposure to fluoride was assessed by the single cell gel (comet assay in vitro. Chinese hamster ovary cells were exposed to sodium fluoride (NaF at final concentration ranging from 7 to 100 µg/ml for 3 h, at 37°C. The results pointed out that NaF in all concentrations tested did not contribute to DNA damage as depicted by the mean tail moment and tail intensity. These findings are clinically important since they represent an important contribution to a correct evaluation of the potential health risk associated with the exposure to dental agents.O flúor tem sido amplamente usado na Odontologia, pois é um agente profilático efetivo e específico contra a cárie dentária. Entretanto, o flúor em excesso pode representar perigos à saúde humana, especialmente por causar agressão ao material genético. Testes de genotoxicidade representam uma importante parte da pesquisa do câncer para a avaliação de risco de possíveis carcinógenos. Neste presente estudo, danos ao DNA associados à exposição ao flúor foram avaliados pelo teste de células individualizadas em gel de agarose (teste do cometa in vitro. Células de ovário de hamster chinês foram expostas ao fluoreto de sódio (NaF nas concentrações finais de 7 a 100 µg/ml, durante 3 h, a 37°C. Os resultados mostraram que o NaF não contribuiu para os danos no DNA em todas as concentrações testadas, conforme demonstrado pelas médias do momento da cauda e da intensidade da cauda dos cometas. Esses achados são clinicamente importantes, uma vez que representam uma importante contribui

  5. 2型糖尿病中国地鼠脂肪肝相关胰岛素抵抗的形成机制%Mechanisms underlying the development of hepatic steatosis-related insulin resistance in Chinese hamsters with type 2 diabetes

    Institute of Scientific and Technical Information of China (English)

    李国生; 刘栩晗; 黄澜; 朱华; 刘亚莉; 马春梅

    2011-01-01

    AIM: To investigate the mechanisms underlying the development of hepatic steatosis-related insulin resistance in Chinese hamsters with type 2 diabetes.METHODS: Insulin-resistant obese Chinese hamsters and Chinese hamsters with type 2 diabetes were generated by feeding a high-fat diet with or without low-dose streptozotocin. Then we investigated the alterations in hepatic gene expression profiles by microarray analysis followed by real-time RT-PCR confirmation.RFESULTS: Microarray analysis indicated that,in insulin-resistant obese Chinese hamsters and those with type 2 diabetes, differentially expressed metabolism-related genes were mainly associated with hepatic glycolipid metabolism and related signaling pathways. Real-time RTPCR analysis verified that the expression of hepatic sterol regulatory element-binding proteins (SREBPs) and peroxisome proliferator-activated receptors (PPAR) γ was increased (all P < 0.05),the expression of liver X receptor αr (LXRα),PPARα, and PPARβ/δ was decreased (all P < 0.05), and the expression of LXR β was unchanged in the liver of hamster models. The expression of hepatic LXR α, SREBPs, PPARs and their target genes in insulin-resistant hamsters significantly differed from that in type 2 diabetic hamsters (all P < 0.05).CONCLUSION: Altered expression of LXR α,SREBPs and PPARs may be involved in the development of hepatic steatosis-related insulin resistance in type 2 diabetic Chinese hamsters.%目的:研究2型糖尿病中国地鼠脂肪肝相关胰岛素抵抗的形成机制.方法:采用高脂饮食及结合小剂量链脲菌素(STZ)的方法建立肥胖胰岛素抵抗地鼠和2型糖尿病中国地鼠模型.应用基因表达芯片技术检测模型地鼠肝脏中基因表达谱的变化,并应用实时定量PCR进行验证.结果:基因芯片结果显示在胰岛素抵抗地鼠和糖尿病地鼠脂肪变的肝脏中,代谢相关差异表达的基因主要与肝脏糖脂代谢及相关信号通路和转录因子/

  6. Stable expression of human H1-histamine-receptor cDNA in Chinese hamster ovary cells. Pharmacological characterisation of the protein, tissue distribution of messenger RNA and chromosomal localisation of the gene.

    Science.gov (United States)

    Moguilevsky, N; Varsalona, F; Noyer, M; Gillard, M; Guillaume, J P; Garcia, L; Szpirer, C; Szpirer, J; Bollen, A

    1994-09-01

    A cDNA clone for the histamine H1 receptor was isolated from a human lung cDNA library; it encoded a protein of 487 amino acids which showed characteristic features of G-protein-coupled receptors. The percentages of identity of the deduced amino acid sequence with bovine, rat and guinea pig H1 histamine receptors were 82.6%, 79.4% and 73.3%, respectively, whereas these percentages decreased to 74.6%, 66% and 56.7% for the amino acid sequence of the third intracellular loop. The human H1-receptor cDNA was transfected into Chinese hamster ovary cells (CHO) via an eukaryotic expression vector; the receptor protein present on cell membranes specifically bound [3H]mepyramine with a Kd of 3.7 nM. The binding was displaced by H1-histamine-receptor antagonists and histamine. Northern blot analysis indicated the presence of two histamine H1 receptor mRNAs of 3.5 kb and 4.1 kb in various human tissues and an additional mRNA of 4.8 kb restricted to the human brain. Finally, by means of somatic cell hybrids segregating either human or rat chromosomes, the gene for histamine H1 receptor was found to reside on human chromosome 3 and rat chromosome 4.

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

    Science.gov (United States)

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

    2010-10-29

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

  8. Comparison of protein patterns of xrs-5, a radiosensitive Chinese hamster ovary cell line, and CHO-K1, its radioresistant parent, using two-dimensional gel-electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Kramer, J.M. (Miami Univ., Oxford, OH (USA). Dept. of Zoology)

    1991-01-01

    X-ray sensitive strains of Chinese hamster ovary cell lines have been used to analyze radiation repair mechanisms. One cell line, xrs-5, has been shown to be very sensitive to ionizing radiation and radical forming chemical mutagens. This sensitivity is thought to be a result a mutation in the DNA double strand break (DSB) repair mechanism, and its characterization has been a goal of several repair mechanism studies. Using two-dimensional gel electrophoresis, we have detected a protein (MW approximately 55KD) in the DNA/Nuclear Matrix (nucleoid) cell fraction of CHO-Kl cells that is absent in the nucleoid fraction of xrs-5. This protein is present, however, in both CHO-Kl and xrs-5 whole cell protein maps. To determine whether the 55KD protein is responsible for the radiosensitive and defective DSB repair phenotype of xrs-5 cells, studies are now underway to analyze revertants of xrs-5 that are proficient in DSB repair. Furthermore, an effort to sequence the protein in question is planned. 23 refs., 2 figs.

  9. THINDOWN IN RADIOBIOLOGY:E.COLI B/r,Bs—1,B.SUBTILUS SPORES,AND V—79 CHINESE HAMSTER CELLS

    Institute of Scientific and Technical Information of China (English)

    张纯祥; RobertKatz

    1995-01-01

    Track theory rested on the foundation of the radial distribution of dose from δ rays as the central contribution of atomic physics to heavy ion radiobiology,Here,a new calculation of the radial distribution of dose is applied,in which the classical angular distribtuion of dose of delta rays and a logarithmic polynomial representation of the electron range-energy relation are used.to form the basis of the present thindown calculation.Calculations of inactivation cross sections for heavy ions in the track width regime displaying thindown for E.Coli B/r and Bs-1,and for Bacillus Subtilus are straightforward for these are 1-hit detectors.Calculations for V-79 hamster cells are more complex.They follow the orginal development of this model for eucaryotic cells,and make use of the cross sections calculated for hypothetical internal targets which are then asserted to be proportional to the measured ceelular inactivation cross sections.The results are in reasonable agreement with experimental ,data.

  10. Radiation-induced bystander effects enhanced by elevated sodium chloride through sensitizing cells to bystander factors

    Energy Technology Data Exchange (ETDEWEB)

    Zhu Lingyan; Han Wei; Chen Shaopeng; Zhao Ye; Jiang Erkang; Bao Lingzhi; Pei Bei; Yang Gen; Zhao Guoping; Wang Jun; Xu An [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, Anhui (China); Wu Lijun [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, P.O. Box 1126, Hefei 230031, Anhui (China)], E-mail: ljw@ipp.ac.cn

    2008-09-26

    Radiation-induced bystander effects (RIBE) have been demonstrated to occur widely in various cell lines. However, very little data is available on the genotoxic effects of RIBE combined with other factor(s). We reported previously that with a low dose of {alpha}-particle irradiation, the fraction of {gamma}-H2AX foci-positive cells in non-irradiated bystander cells was significantly increased under elevated NaCl culture conditions. In this study, we further investigated the functional role of NaCl in the enhancement of RIBE using a specially designed co-culture system and micronucleus (MN) test. It was shown that the MN frequency was not increased significantly by elevated NaCl (9.0 g/L) alone or by medium exposure. However, with 1.0 cGy {alpha}-particle irradiation, the induced MN frequency increased significantly in both irradiated and non-irradiated bystander regions. Additional studies showed that elevated NaCl made the non-irradiated bystander cells more vulnerable to bystander factors. Furthermore, it was found that the induced MN frequency in cells both in irradiated and non-irradiated bystander regions was weakened when the hypertonic medium was changed to normotonic medium for 2 h before irradiation. Such observations were quite similar to the co-effect of NaCl and hydrogen peroxide (H{sub 2}O{sub 2}), indicating that elevated NaCl might sensitize non-irradiated cells to bystander factors-induced oxidative stress.

  11. Beschermingsplan hamster 2005-2010

    NARCIS (Netherlands)

    Haye, la M.J.J.; Jansman, H.A.H.

    2005-01-01

    Alterra-Concept van het beschermingsplan hamster 2005-2010. De hamster is in het meest westelijke deel van het Europese verspreidingsgebied bedreigd. De kennis die in de afgelopen periode is opgedaan van de hamster en de maatregelen die in het veld zijn uitgevoerd vormen de basis voor dit tweede Bes

  12. Brief report: The bystander effect in cyberbullying incidents.

    Science.gov (United States)

    Machackova, Hana; Dedkova, Lenka; Mezulanikova, Katerina

    2015-08-01

    This study examined the bystander effect in cyberbullying. Using self-reported data from 257 Czech respondents who had witnessed a cyberbullying attack, we tested whether provided help decreased with increased number of other bystanders. We controlled for several individual and contextual factors, including empathy, social self-efficacy, empathic response to victimization, and relationship to the victim. Results showed that participants tend to help the victims more in incidents with only one or two other bystanders. We also found that, as in the "offline" realm, bystander effect is not linear: no significant differences were found between incidents with a moderate number (3-10) and a larger number of total bystanders. Our findings, thus, provide support for the presence of the bystander effect in cyberbullying.

  13. Neutron induced bystander effect among zebrafish embryos

    Science.gov (United States)

    Ng, C. Y. P.; Kong, E. Y.; Kobayashi, A.; Suya, N.; Uchihori, Y.; Cheng, S. H.; Konishi, T.; Yu, K. N.

    2015-12-01

    The present paper reported the first-ever observation of neutron induced bystander effect (NIBE) using zebrafish (Danio rerio) embryos as the in vivo model. The neutron exposure in the present work was provided by the Neutron exposure Accelerator System for Biological Effect Experiments (NASBEE) facility at the National Institute of Radiological Sciences (NIRS), Chiba, Japan. Two different strategies were employed to induce NIBE, namely, through directly partnering and through medium transfer. Both results agreed with a neutron-dose window (20-50 mGy) which could induce NIBE. The lower dose limit corresponded to the threshold amount of neutron-induced damages to trigger significant bystander signals, while the upper limit corresponded to the onset of gamma-ray hormesis which could mitigate the neutron-induced damages and thereby suppress the bystander signals. Failures to observe NIBE in previous studies were due to using neutron doses outside the dose-window. Strategies to enhance the chance of observing NIBE included (1) use of a mono-energetic high-energy (e.g., between 100 keV and 2 MeV) neutron source, and (2) use of a neutron source with a small gamma-ray contamination. It appeared that the NASBEE facility used in the present study fulfilled both conditions, and was thus ideal for triggering NIBE.

  14. Measuring Bystander Attitudes and Behavior to Prevent Sexual Violence

    Science.gov (United States)

    McMahon, Sarah; Allen, Christopher T.; Postmus, Judy L.; McMahon, Sheila M.; Peterson, N. Andrew; Lowe Hoffman, Melanie

    2014-01-01

    Objective: The purpose of this study is to further investigate the factor structure and strength of the Bystander Attitude Scale-Revised and Bystander Behavior Scale-Revised (BAS-R and BBS-R). Participants: First-year students (N = 4,054) at a large public university in the Northeast completed a survey in 2010 as part of a larger longitudinal…

  15. The Bystander in Commercial Life : Obliged by Beneficence or Rescue

    NARCIS (Netherlands)

    Dubbink, Wim

    2016-01-01

    Liberalist thinking argues that moral agents have a right (or duty) to pursue an ordinary life. It also insists that moral agent can be bystanders. A bystander is involved with morally bad states of affairs in the sense that they are bound by moral duty, but for a non-blameworthy reason. A common vi

  16. The lonely bystander: ostracism leads to less helping in virtual bystander situations

    NARCIS (Netherlands)

    Bommel, van Marco; Prooijen, van Jan-Willem; Elffers, Henk; Lange, van Paul A.M.

    2016-01-01

    People are less likely to help when they have been ostracized, or when they are in the presence of bystanders. In the current manuscript we test both these influences simultaneously. We postulated two opposing hypotheses: first, helping decreases after ostracism, even when intervention is already le

  17. Evaluation of the radio modifier effect of propolis on chinese hamster ovary (CHO-K1) and human prostate cancer (PC3) cells, irradiated with 60-CO; Avaliacao do efeito radiomodificador da propolis em celulas de ovario de hamster chines (CHO-K1) e em celulas tumorais de prostata (PC3), irradiadas com CO-60

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Geyza Spigoti

    2011-07-01

    In the last decades, it has been given a great interest to investigations concerning natural, effective, nontoxic compounds with radioprotective potential together with the increasing utilization of different types of ionizing radiation for various applications. Among them propolis, a resinous compound produced by honeybees (Apis mellifera), has been considered quite promising, since it presents several advantageous biological characteristics, i. e., anti-inflammatory, antimicrobial, anticarcinogenic, antioxidant and also free radical scavenging action. The purpose of the present study was to evaluate the effect of Brazilian propolis, collected in the State of Rio Grande do Sul, on Chinese hamster ovary (CHO-K1) and human prostate cancer (PC3) cells, irradiated with {sup 60}Co {gamma} radiation. For this purpose, three interlinked parameters were analyzed: micronucleus induction, cell viability and clonogenic death. The choice of these parameters was justified by their biological significance, in addition to the fact that they are readily observable and measurable in irradiated cells. The cytogenetic data obtained showed a radioprotective effect of propolis (5-100 {mu}g/ml) in the induction of DNA damage for both cell lines, irradiated with doses of 1 - 4 Gy. The cytotoxicity assay, however, showed a prominent antiproliferative effect of propolis (50 - 400{mu}/ml) in PC3 cells irradiated with 5 G{gamma}. The survival curves obtained were adequately fitted by a linear-quadratic model, where the {alpha} coefficient was higher in CHO-K1 cells. Concerning the clonogenic capacity, PC3 cells were more radiosensitive than CHO-K1 cells at the higher doses of the survival curve. Propolis at the concentrations of 30 - 100 {mu}g/ml, did not influence the clonogenic potential of PC3 cells, since the survival curves, associated or not with propolis, were found similar, although the combined treatment in CHO-K1 cells exhibited a stimulating proliferative effect. The data

  18. The Bystander-Effect: A Meta-Analytic Review on Bystander Intervention in Dangerous and Non-Dangerous Emergencies

    Science.gov (United States)

    Fischer, Peter; Krueger, Joachim I.; Greitemeyer, Tobias; Vogrincic, Claudia; Kastenmuller, Andreas; Frey, Dieter; Heene, Moritz; Wicher, Magdalena; Kainbacher, Martina

    2011-01-01

    Research on bystander intervention has produced a great number of studies showing that the presence of other people in a critical situation reduces the likelihood that an individual will help. As the last systematic review of bystander research was published in 1981 and was not a quantitative meta-analysis in the modern sense, the present…

  19. Enteropathogenic Escherichia coli: foe or innocent bystander?

    Science.gov (United States)

    Hu, J; Torres, A G

    2015-08-01

    Enteropathogenic Escherichia coli (EPEC) remain one the most important pathogens infecting children and they are one of the main causes of persistent diarrhoea worldwide. Historically, typical EPEC (tEPEC), defined as those isolates with the attaching and effacement (A/E) genotype (eae(+)), which possess bfpA(+) and lack the stx(-) genes are found strongly associated with diarrhoeal cases. However, occurrence of atypical EPEC (aEPEC; eae(+)bfpA(-)stx(-)) in diarrhoeal and asymptomatic hosts has made investigators question the role of these pathogens in human disease. Current epidemiological data are helping to answer the question of whether EPEC is mainly a foe or an innocent bystander during infection.

  20. Radiation-induced bystander effects in vivo are sex specific

    Energy Technology Data Exchange (ETDEWEB)

    Koturbash, Igor; Kutanzi, Kristy; Hendrickson, Karl; Rodriguez-Juarez, Rocio; Kogosov, Dmitry [Department of Biological Sciences, University of Lethbridge, Alberta T1K 3M4 (Canada); Kovalchuk, Olga [Department of Biological Sciences, University of Lethbridge, Alberta T1K 3M4 (Canada)], E-mail: olga.kovalchuk@uleth.ca

    2008-07-03

    Ionizing radiation (IR) effects span beyond the area of direct exposure and can be observed in neighboring and distant naive cells and organs. This phenomenon is termed a 'bystander effect'. IR effects in directly exposed tissue in vivo are epigenetically mediated and distinct in males and females. Yet, IR-induced bystander effects have never been explored in a sex-specificity domain. We used an in vivo mouse model, whereby the bystander effects are studied in spleen of male and female animals subjected to head exposure when the rest of the body is protected by a medical-grade lead shield. We analyzed the induction of DNA damage and alterations in global DNA methylation. Molecular parameters were correlated with cellular proliferation and apoptosis levels. The changes observed in bystander organs are compared to the changes in unexposed animals and animals exposed to predicted and measured scatter doses. We have found the selective induction of DNA damage levels, global DNA methylation, cell proliferation and apoptosis in exposed and bystander spleen tissue of male and female mice. Sex differences were significantly diminished in animals subjected to a surgical removal of gonads. These data constitute the first evidence of sex differences in radiation-induced bystander effects in mouse spleen in vivo. We show the role of sex hormones in spleen bystander responses and discuss implications of the observed changes.

  1. Mitochondrial mutagenesis induced by tumor-specific radiation bystander effects.

    LENUS (Irish Health Repository)

    Gorman, Sheeona

    2012-02-01

    The radiation bystander effect is a cellular process whereby cells not directly exposed to radiation display cellular alterations similar to directly irradiated cells. Cellular targets including mitochondria have been postulated to play a significant role in this process. In this study, we utilized the Random Mutation Capture assay to quantify the levels of random mutations and deletions in the mitochondrial genome of bystander cells. A significant increase in the frequency of random mitochondrial mutations was found at 24 h in bystander cells exposed to conditioned media from irradiated tumor explants (p = 0.018). CG:TA mutations were the most abundant lesion induced. A transient increase in the frequency of random mitochondrial deletions was also detected in bystander cells exposed to conditioned media from tumor but not normal tissue at 24 h (p = 0.028). The increase in both point mutations and deletions was transient and not detected at 72 h. To further investigate mitochondrial dysfunction, mitochondrial membrane potential and reactive oxygen species were assessed in these bystander cells. There was a significant reduction in mitochondrial membrane potential and this was positively associated with the frequency of random point mutation and deletions in bystander cells treated with conditioned media from tumor tissue (r = 0.71, p = 0.02). This study has shown that mitochondrial genome alterations are an acute consequence of the radiation bystander effect secondary to mitochondrial dysfunction and suggests that this cannot be solely attributable to changes in ROS levels alone.

  2. Poly(N-isopropylacrylamide)-coated thermo-responsive nanoparticles for controlled delivery of sulfonated Zn-phthalocyanine in Chinese hamster ovary cells in vitro and zebra fish in vivo

    Science.gov (United States)

    He, Jia; Chen, Ji-Yao; Wang, Pu; Wang, Pei-Nan; Guo, Jia; Yang, Wu-Li; Wang, Chang-Chun; Peng, Qian

    2007-10-01

    Poly(N-isopropylacrylamide) (PNIPAM)-coated Fe3O4@SiO2@CdTe multifunctional nanoparticles with photoluminescent (PL), thermosensitive and magnetic properties, were investigated as carriers to deliver water-soluble, fluorescent sulfonated Zn-phthalocyanine (ZnPcS), a photosensitizing drug for photodynamic therapy of cancer, in Chinese hamster ovary (CHO) cells in vitro and zebra fish in vivo. PNIPAM is a well-known thermo-responsive polymer with a volume phase transition temperature. This property allows it to be swollen in water at temperatures lower than 32-34 °C to take up ZnPcS and shrunken to expel the drug at higher temperatures. Since the PL band of CdTe quantum dots (QDs) as indicators for the nanoparticles is at 585 nm and the emission band of ZnPcS is at 680 nm, it is possible to study the temperature-dependent release of ZnPcS from the nanoparticles by fluorescence measurements. ZnPcS was embedded in the PNIPAM of the nanoparticles at 25 °C in phosphate buffered saline (PBS) solution and released at 37 °C, measured with a spectrophotometer. When CHO cells had been incubated with the ZnPcS-loaded nanoparticles at 27 °C, a similar intracellular localization pattern of CdTe QDs and ZnPcS was seen by multichannel measurements in confocal laser scanning microscopy (CLSM), but a diffuse pattern of only ZnPcS fluorescence was detected in the cytoplasm of the cells at 37 °C, indicating a release of ZnPcS from the nanoparticles. Similar results were also found in the intestinal tract of zebra fish in vivo after intake of the nanoparticles. Since the nanoparticles contain magnetic (Fe3O4) material, the nanoparticles could also be manipulated to change their location in the intestinal tract of the zebra fish with an external magnetic field gradient of 300 G mm-1. The results presented suggest that such multifunctional nanoparticles may have combined potential for temperature-dependent drug delivery, QD photodetection and magnetic manipulation in diagnosis and

  3. Poly(N-isopropylacrylamide)-coated thermo-responsive nanoparticles for controlled delivery of sulfonated Zn-phthalocyanine in Chinese hamster ovary cells in vitro and zebra fish in vivo

    Energy Technology Data Exchange (ETDEWEB)

    He Jia [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai (China); Chen Jiyao [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai (China); Wang Pu [Surface Physics Laboratory (National Key Laboratory) and Department of Physics, Fudan University, Shanghai (China); Wang Peinan [State Key Laboratory for Advanced Photonic Materials and Devices, Fudan University, Shanghai (China); Guo Jia [Department of Macromolecular Science and Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai (China); Yang Wuli [Department of Macromolecular Science and Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai (China); Wang Changchun [Department of Macromolecular Science and Key Laboratory of Molecular Engineering of Polymers, Fudan University, Shanghai (China); Peng Qian [State Key Laboratory for Advanced Photonic Materials and Devices, Fudan University, Shanghai (China)

    2007-10-17

    Poly(N-isopropylacrylamide) (PNIPAM)-coated Fe{sub 3}O{sub 4} - SiO{sub 2} - CdTe multifunctional nanoparticles with photoluminescent (PL), thermosensitive and magnetic properties, were investigated as carriers to deliver water-soluble, fluorescent sulfonated Zn-phthalocyanine (ZnPcS), a photosensitizing drug for photodynamic therapy of cancer, in Chinese hamster ovary (CHO) cells in vitro and zebra fish in vivo. PNIPAM is a well-known thermo-responsive polymer with a volume phase transition temperature. This property allows it to be swollen in water at temperatures lower than 32-34 deg. C to take up ZnPcS and shrunken to expel the drug at higher temperatures. Since the PL band of CdTe quantum dots (QDs) as indicators for the nanoparticles is at 585 nm and the emission band of ZnPcS is at 680 nm, it is possible to study the temperature-dependent release of ZnPcS from the nanoparticles by fluorescence measurements. ZnPcS was embedded in the PNIPAM of the nanoparticles at 25 deg. C in phosphate buffered saline (PBS) solution and released at 37 deg. C, measured with a spectrophotometer. When CHO cells had been incubated with the ZnPcS-loaded nanoparticles at 27 deg. C, a similar intracellular localization pattern of CdTe QDs and ZnPcS was seen by multichannel measurements in confocal laser scanning microscopy (CLSM), but a diffuse pattern of only ZnPcS fluorescence was detected in the cytoplasm of the cells at 37 deg. C, indicating a release of ZnPcS from the nanoparticles. Similar results were also found in the intestinal tract of zebra fish in vivo after intake of the nanoparticles. Since the nanoparticles contain magnetic (Fe{sub 3}O{sub 4}) material, the nanoparticles could also be manipulated to change their location in the intestinal tract of the zebra fish with an external magnetic field gradient of 300 G mm{sup -1}. The results presented suggest that such multifunctional nanoparticles may have combined potential for temperature-dependent drug delivery, QD

  4. Intracellular transactivation of epidermal growth factor receptor by α1A-adrenoceptor is mediated by phosphatidylinositol 3-kinase independently of activation of extracellular signal regulated kinases 1/2 and serine-threonine kinases in Chinese hamster ovary cells.

    Science.gov (United States)

    Ulu, Nadir; Henning, Robert H; Guner, Sahika; Zoto, Teuta; Duman-Dalkilic, Basak; Duin, Marry; Gurdal, Hakan

    2013-10-01

    Transactivation of epidermal growth factor receptor (EGFR) by α1-adrenoceptor (α1-AR) is implicated in contraction and hypertrophy of vascular smooth muscle (VSM). We examine whether all α1-AR subtypes transactivate EGFR and explore the mechanism of transactivation. Chinese hamster ovary (CHO) cells stably expressing one subtype of α1-AR were transiently transfected with EGFR. The transactivation mechanism was examined both by coexpression of a chimeric erythropoietin (EPO)-EGFR with an extracellular EPO and intracellular EGFR domain, and by pharmacologic inhibition of external and internal signaling routes. All three α1-AR subtypes transactivated EGFR, which was dependent on the increase in intracellular calcium. The EGFR kinase inhibitor AG1478 [4-(3'-chloroanilino)-6,7-dimethoxyquinazoline] abrogated α1A-AR and α1D-AR induced phosphorylation of EGFR, but both the inhibition of matrix metalloproteinases by GM6001 [(R)-N4-hydroxy-N(1)-[(S)-2-(1H-indol-3-yl)-1-methylcarbamoyl-ethyl]-2-isobutyl-succinamide] or blockade of EGFR by cetuximab did not. Stimulation of α1A-AR and α1D-AR also induced phosphorylation of EPO-EGFR chimeric receptors. Moreover, α1A-AR stimulation enhanced phosphorylation of extracellular signal regulated kinase (ERK) 1/2 and serine-threonine kinases (Akt), which were both unaffected by AG1478, indicating that ERK1/2 and Akt phosphorylation is independent of EGFR transactivation. Accordingly, inhibitors of ERK1/2 or Akt did not influence the α1A-AR-mediated EGFR transactivation. Inhibition of calcium/calmodulin-dependent kinase II (CaMKII), phosphatidylinositol 3-kinase (PI3K), and Src, however, did block EGFR transactivation by α1A-AR and α1D-AR. These findings demonstrate that all α1-AR subtypes transactivate EGFR, which is dependent on an intracellular signaling route involving an increase in calcium and activation of CaMKII, PI3K, and Src, but not the of ERK1/2 and Akt pathways.

  5. VEGF siRNA致中国仓鼠肺细胞染色体畸变的研究%Research of chromosome aberration in Chinese hamster lung fibroblast induced by VEGF siRNA

    Institute of Scientific and Technical Information of China (English)

    荆春霞; 张洹; 杨光; 吴赤蓬; 何林

    2011-01-01

    Objective To explore the effects of VECF siRNA on chromosome aberration in Chinese hamster lung fibroblasts (CHL). Methods The chromosome aberrations were observed after CHL were transfected with VECF siRNA for 24 hours and 48h. Results There were a questionable positive in 100nmol/L VEGF siRNA after VECF siRNA were transfected for 24h and the chromosome aberration rate was 6 percentages. Both 50nmol/L VEGF siRNA and 100nmol/L VECF siRNA caused the questionable positive after VEGF siRNAs were transfected for 48h, and the chromosome aberration rates was 6 percentages and 10 percentages separately. There were no the chromosome aberration in 25nmol/L VEGF siRNA. The types of chromosomal aberration induced by VEGF siRNAs included break, Dicentric grain, polyploid, gap, and three trajectories. Conclusion lOOnmol/L VEGF siRNA might cause CHL chromosome aberration.%目的 研究VEGF siRNA对中国仓鼠肺细胞(CHL)的染色体畸变作用.方法 采用25、50和100nmol/L的VEGF siRNA转染中国仓鼠的肺细胞,分别观察24h、48h后的染色体畸变情况.结果 在VEGFsiRNA转染24小时,仅100nmol/L VEGF siRNA产生可疑阳性反应,其染色体的畸变率为6%;在VEGFsiRNA转染48小时后,50nmol/L的VEGF siRNA和100nmol/L的VEGF siRNA均产生可疑阳性反应,染色体的畸变率分别为6%和10%.而25nmol/L的VEGF siRNA无论是在转染后24h还是48h,均未产生染色体的畸变作用.VEGF siRNA产生的染色体畸变类型有断裂、双着丝粒、多倍体、裂隙、三射体.结论 100nmol/L的VEGFsiRNA分子可引起CHL细胞产生染色体畸变.

  6. Understanding of decreased sialylation of Fc-fusion protein in hyperosmotic recombinant Chinese hamster ovary cell culture: N-glycosylation gene expression and N-linked glycan antennary profile.

    Science.gov (United States)

    Lee, Jong Hyun; Jeong, Yeong Ran; Kim, Yeon-Gu; Lee, Gyun Min

    2017-03-07

    To understand the effects of hyperosmolality on protein glycosylation, recombinant Chinese hamster ovary (rCHO) cells producing the Fc-fusion protein were cultivated in hyperosmolar medium resulting from adding NaCl (415 mOsm/kg). The hyperosmotic culture showed increased specific Fc-fusion protein productivity (qFc ) but a decreased proportion of acidic isoforms and sialic acid content of the Fc-fusion protein. The intracellular and extracellular sialidase activities in the hyperosmotic cultures were similar to those in the control culture (314 mOsm/kg), indicating that reduced sialylation of Fc-fusion protein at hyperosmolality was not due to elevated sialidase activity. Expression of 52 N-glycosylation-related genes was assessed by the NanoString nCounter system, which provides a direct digital readout using custom-designed color-coded probes. After three days of hyperosmotic culture, nine genes (ugp, slc35a3, slc35d2, gcs1, manea, mgat2, mgat5b, b4galt3, and b4galt4) were differentially expressed over 1.5-fold of the control, and all these genes were down-regulated. N-linked glycan analysis by anion exchange and hydrophilic interaction HPLC showed that the proportion of highly sialylated (di-, tri-, tetra-) and tetra-antennary N-linked glycans was significantly decreased upon hyperosmotic culture. Addition of betaine, an osmoprotectant, to the hyperosmotic culture significantly increased the proportion of highly sialylated and tetra-antennary N-linked glycans (P ≤ 0.05), while it increased the expression of the N-glycan branching/antennary genes (mgat2 and mgat4b). Thus, decreased expression of the genes with roles in the N-glycan biosynthesis pathway correlated with reduced sialic acid content of Fc-fusion protein caused by hyperosmolar conditions. Taken together, the results obtained in this study provide a better understanding of the detrimental effects of hyperosmolality on N-glycosylation, especially sialylation, in rCHO cells. This article is protected

  7. Sequencing, annotation and analysis of the Syrian hamster (Mesocricetus auratus transcriptome.

    Directory of Open Access Journals (Sweden)

    Nicolas Tchitchek

    Full Text Available The Syrian hamster (golden hamster, Mesocricetus auratus is gaining importance as a new experimental animal model for multiple pathogens, including emerging zoonotic diseases such as Ebola. Nevertheless there are currently no publicly available transcriptome reference sequences or genome for this species.A cDNA library derived from mRNA and snRNA isolated and pooled from the brains, lungs, spleens, kidneys, livers, and hearts of three adult female Syrian hamsters was sequenced. Sequence reads were assembled into 62,482 contigs and 111,796 reads remained unassembled (singletons. This combined contig/singleton dataset, designated as the Syrian hamster transcriptome, represents a total of 60,117,204 nucleotides. Our Mesocricetus auratus Syrian hamster transcriptome mapped to 11,648 mouse transcripts representing 9,562 distinct genes, and mapped to a similar number of transcripts and genes in the rat. We identified 214 quasi-complete transcripts based on mouse annotations. Canonical pathways involved in a broad spectrum of fundamental biological processes were significantly represented in the library. The Syrian hamster transcriptome was aligned to the current release of the Chinese hamster ovary (CHO cell transcriptome and genome to improve the genomic annotation of this species. Finally, our Syrian hamster transcriptome was aligned against 14 other rodents, primate and laurasiatheria species to gain insights about the genetic relatedness and placement of this species.This Syrian hamster transcriptome dataset significantly improves our knowledge of the Syrian hamster's transcriptome, especially towards its future use in infectious disease research. Moreover, this library is an important resource for the wider scientific community to help improve genome annotation of the Syrian hamster and other closely related species. Furthermore, these data provide the basis for development of expression microarrays that can be used in functional genomics studies.

  8. Marketing defibrillation training programs and bystander intervention support.

    Science.gov (United States)

    Sneath, Julie Z; Lacey, Russell

    2009-01-01

    This exploratory study identifies perceptions of and participation in resuscitation training programs, and bystanders' willingness to resuscitate cardiac arrest victims. While most of the study's participants greatly appreciate the importance of saving someone's life, many indicated that they did not feel comfortable assuming this role. The findings also demonstrate there is a relationship between type of victim and bystanders' willingness to intervene. Yet, bystander intervention discomfort can be overcome with cardiopulmonary resuscitation and defibrillation training, particularly when the victim is a coworker or stranger. Further implications of these findings are discussed and modifications to public access defibrillation (PAD) training programs' strategy and communications are proposed.

  9. Study on hprt locus mutation in Chinese hamster lung cells induced by 1-bromopropane%1-溴丙烷致中国仓鼠肺细胞hprt基因位点突变作用研究

    Institute of Scientific and Technical Information of China (English)

    李宏玲; 殷霄; 王海兰; 赵娜; 王恰; 宋向荣; 越飞

    2012-01-01

    Objective To study the effect of 1-bromopropane (1-BP) on hprt locus mutation in Chinese hamster lung cells. Methods The hprt locus mutation was examined at different dose levels of 1 -BP in absence and presence of S9 ( - S9 and + S9 ) metabolic activation system. V79 cells were treated with 1 -BP at the doses of 3. 375 , 6. 750,13. 500 g/L for 6 hours respectively. 1.000 g/L EMS ( -S9) and 0.001 g/L MNNG ( +S9) were given as the positive control groups, while serum free medium was designed to the negative control groups. The mutant frequency was counted by cell-cloning. Results Under the condition of - S9 metabolic activation system, the differences of mutant frequency among all treatment groups and solvent control group were not significant ( P > 0. 05). When S9 metabolic activation system was added, the mutant frequencies in 3. 375 g/L and 6. 750 g/L treatment groups were significantly higher than those in solvent control group (P < 0. 01 ) , but without dose-response relationship. Conclusion In the presence of S9 metabolic activation system, 1 -BP might induce hprt locus mutation in V79 cells.%目的 探讨1-溴丙烷(1-BP)对中国仓鼠肺细胞(V79)次黄嘌呤鸟嘌呤磷酸核糖转移酶(hprt)基因位点的致突变作用.方法 将V79分为大鼠肝微粒体混合功能氧化酶(S9)代谢活化系和非S9代谢活化系,每系各设3.375、6.750、13.500 g/L3个不同质量浓度的1-BP实验组;另设1.000 g/L甲磺酸乙酯阳性对照组(非S9代谢活化系)、0.001g/L甲基硝基亚硝基胍阳性对照组(S9代谢活化系)和溶剂对照组,溶剂对照组加等体积的无血清培养基.染毒时间为6h.应用细胞克隆检测法检测V79 hprt基因位点的突变率.结果 非S9代谢活化系,1-BP实验组突变率与溶剂对照组比较,差异均无统计学意义(P>0.05);S9代谢活化系,3.375、6.750 g/L 1-BP实验组突变率均高于溶剂对照组,差异均有统计学意义(P<0.01),但不存在剂量-反应关系.结论 1-BP

  10. Radioprotection of targeted and bystander cells by methylproamine

    Energy Technology Data Exchange (ETDEWEB)

    Burdak-Rothkamm, Susanne [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast (United Kingdom); Oxford University Hospitals, Cellular Pathology, Oxford (United Kingdom); Smith, Andrea; Lobachevsky, Pavel; Martin, Roger [Peter MacCallum Cancer Centre, Molecular Radiation Biology Laboratory, Melbourne (Australia); University of Melbourne, The Sir Peter MacCallum Department of Oncology, Melbourne (Australia); Prise, Kevin M. [Queen' s University Belfast, Centre for Cancer Research and Cell Biology, Belfast (United Kingdom)

    2014-09-23

    Radioprotective agents are of interest for application in radiotherapy for cancer and in public health medicine in the context of accidental radiation exposure. Methylproamine is the lead compound of a class of radioprotectors which act as DNA binding anti-oxidants, enabling the repair of transient radiation-induced oxidative DNA lesions. This study tested methylproamine for the radioprotection of both directly targeted and bystander cells. T98G glioma cells were treated with 15 μM methylproamine and exposed to {sup 137}Cs γ-ray/X-ray irradiation and He{sup 2+} microbeam irradiation. Radioprotection of directly targeted cells and bystander cells was measured by clonogenic survival or γH2AX assay. Radioprotection of directly targeted T98G cells by methylproamine was observed for {sup 137}Cs γ-rays and X-rays but not for He{sup 2+} charged particle irradiation. The effect of methylproamine on the bystander cell population was tested for both X-ray irradiation and He{sup 2+} ion microbeam irradiation. The X-ray bystander experiments were carried out by medium transfer from irradiated to non-irradiated cultures and three experimental designs were tested. Radioprotection was only observed when recipient cells were pretreated with the drug prior to exposure to the conditioned medium. In microbeam bystander experiments targeted and nontargeted cells were co-cultured with continuous methylproamine treatment during irradiation and postradiation incubation; radioprotection of bystander cells was observed. Methylproamine protected targeted cells from DNA damage caused by γ-ray or X-ray radiation but not He{sup 2+} ion radiation. Protection of bystander cells was independent of the type of radiation which the donor population received. (orig.) [German] Radioprotektive Agenzien sind sowohl in der Strahlentherapie von Krebserkrankungen als auch im Strahlenschutz im Zusammenhang mit akzidenteller Exposition von Bedeutung. Methylproamine ist die Leitsubstanz einer Klasse von

  11. Recursive mentalizing and common knowledge in the bystander effect.

    Science.gov (United States)

    Thomas, Kyle A; De Freitas, Julian; DeScioli, Peter; Pinker, Steven

    2016-05-01

    The more potential helpers there are, the less likely any individual is to help. A traditional explanation for this bystander effect is that responsibility diffuses across the multiple bystanders, diluting the responsibility of each. We investigate an alternative, which combines the volunteer's dilemma (each bystander is best off if another responds) with recursive theory of mind (each infers what the others know about what he knows) to predict that actors will strategically shirk when they think others feel compelled to help. In 3 experiments, participants responded to a (fictional) person who needed help from at least 1 volunteer. Participants were in groups of 2 or 5 and had varying information about whether other group members knew that help was needed. As predicted, people's decision to help zigzagged with the depth of their asymmetric, recursive knowledge (e.g., "John knows that Michael knows that John knows help is needed"), and replicated the classic bystander effect when they had common knowledge (everyone knowing what everyone knows). The results demonstrate that the bystander effect may result not from a mere diffusion of responsibility but specifically from actors' strategic computations.

  12. DMPD: TLR3 in antiviral immunity: key player or bystander? [Dynamic Macrophage Pathway CSML Database

    Lifescience Database Archive (English)

    Full Text Available 16027039 TLR3 in antiviral immunity: key player or bystander? Schroder M, Bowie AG.... Trends Immunol. 2005 Sep;26(9):462-8. (.png) (.svg) (.html) (.csml) Show TLR3 in antiviral immunity: key pl...ayer or bystander? PubmedID 16027039 Title TLR3 in antiviral immunity: key player or bystander? Authors Schr

  13. Promoting Prosocial Behaviors to Prevent Dating Violence among College Students: Evaluation of a Bystander Intervention

    Science.gov (United States)

    Borsky, Amanda E.

    2014-01-01

    The objective of this dissertation was to evaluate a bystander behavior program at the Jefferson College of Health Sciences (JCHS) in Roanoke, Virginia. Specifically, this dissertation examined the: (1) preliminary measurement properties of a newly developed bystander behavior intention scale; (2) impact of the bystander intervention at JCHS; and…

  14. Caffeine Markedly Enhanced Radiation-Induced Bystander Effects

    Institute of Scientific and Technical Information of China (English)

    JIANG Erkang; WU Lijun

    2009-01-01

    A bstract In this paper it is shown that incubation with 2 mM caffeine enhanced significantly the MN (micronucleus) formation in both the 1 cGy a-particle irradiated and non-irradiated by- stander regions. Moreover, caffeine treatment made the non-irradiated bystander cells more sensi- tive to damage signals. Treated by c-PTIO(2-(4-carboxy-phenyl)-4,4,5,5-tetramethyl-imidazoline- 1-oxyl-3-oxide), a nitric oxide (NO) scavenger, the MN frequencies were effectively inhibited, showing that nitric oxide might be very important in mediating the enhanced damage. These results indicated that caffeine enhanced the low dose a-particle radiation-induced damage in ir- radiated and non-irradiated bystander regions, and therefore it is important to investigate the relationship between the radiosensitizer and radiation-induced bystander effects (RIBE).

  15. Workplace mobbing: How the victim's coping behavior influences bystander responses.

    Science.gov (United States)

    Mulder, Roelie; Bos, Arjan E R; Pouwelse, Mieneke; van Dam, Karen

    2017-01-01

    Victims of workplace mobbing show diverse coping behavior. We investigated the impact of this behavior on bystander cognitions, emotions, and helping toward the victim, integrating coping literature with attribution theory. Adult part-time university students (N = 161) working at various organizations participated in a study with a 3(Coping: approach/avoidance/neutral) × 2(Gender Victim: male/female) × 2(Gender Bystander: male/female) design. Victims showing approach (vs. avoidance) coping were considered to be more self-reliant and less responsible for the continuation of the mobbing, and they elicited less anger. Continuation responsibility and self-reliance mediated the relationship between the victim's coping behavior and bystanders' helping intentions. Female (vs. male) participants reported more sympathy for the victim and greater willingness to help, and female (vs. male) victims elicited less anger. Theoretical and practical implications of the findings are discussed.

  16. Bystander Effects During Synchrotron Imaging Procedures?

    Science.gov (United States)

    Schültke, Elisabeth; Bewer, Brian; Wysokinski, Tomasz; Chapman, Dean; Nikkhah, Guido

    2010-07-01

    Using monochromatic beam and synchrotron phase-contrast technique at the biomedical beamline of the Italian synchrotron facility Elettra (SYRMEP), we have shown in a small animal model of malignant brain tumor that it is possible to obtain high-resolution images of very small tumors when they have developed from implanted tumor cells loaded with colloidal gold nanoparticles (GNP). All previous experiments were conducted in post-mortem samples. We have now designed a cell culture experiment to investigate the effects of synchrotron radiation with an energy and dose profile similar to that expected in our first in vivo imaging studies according to the protocol developed at SYRMEP. Materials and Methods: Culture flasks containing either gold-loaded or naïve C6 glioma cells were exposed to a dose of 0.5 Gy at 24 keV. The irradiated medium was aspirated and replaced with fresh growth medium. Twenty-four hours later this non-irradiated medium exposed to irradiated cells was aspirated, then added to non-irradiated C6 cells in order to investigate whether bystander effects are seen under the conditions of our image acquisition protocol. The irradiated medium was added to a number of other non-irradiated cell cultures. Cell counts were followed until 72 hrs after irradiation. Western blots were conducted with H2AX antibodies. This experiment was one of the first biomedical experiments conducted at BMIT, the new biomedical imaging and therapy beamline of the Canadian Light Source. Results: No significant differences in proliferation were seen between cells that were directly irradiated, exposed to irradiated medium or exposed to the non-irradiated 24-hr-medium from the irradiated cells. However, there was a tendency towards a higher number of double strand breaks in previously irradiated cells when they were exposed to non-irradiated medium that had been in contact with irradiated cells for 24 hrs.

  17. Mechanism of bystander-blaming: defensive attribution, counterfactual thinking, and gender.

    Science.gov (United States)

    Levy, Inna; Ben-David, Sarah

    2015-01-01

    Contemporary victimology recognizes that an understanding of the mechanism of blaming requires a comprehensive approach that includes the victim, the offender, and the bystander. However, most of the existing research on blaming focuses on the victim and the offender, ignoring the issue of bystander-blaming. This study highlights the bystander and investigates bystander-blaming by exploring some theoretical explanations, including counterfactual thinking, defensive attribution, and gender differences. The study included 363 young male and female participants, who read vignettes describing the behavior of the victim and the bystander in a rape scenario and answered questions regarding bystander-blaming. The results show that both counterfactual thinking and defensive attribution play a role in bystander-blaming. This article addresses the theoretical and practical implications of these findings.

  18. Daidzin inhibits mitochondrial aldehyde dehydrogenase and suppresses ethanol intake of Syrian golden hamsters.

    Science.gov (United States)

    Keung, W M; Klyosov, A A; Vallee, B L

    1997-03-04

    Daidzin is the major active principle in extracts of radix puerariae, a traditional Chinese medication that suppresses the ethanol intake of Syrian golden hamsters. It is the first isoflavone recognized to have this effect. Daidzin is also a potent and selective inhibitor of human mitochondrial aldehyde dehydrogenase (ALDH-2). To establish a link between these two activities, we have tested a series of synthetic structural analogs of daidzin. The results demonstrate a direct correlation between ALDH-2 inhibition and ethanol intake suppression and raise the possibility that daidzin may, in fact, suppress ethanol intake of golden hamsters by inhibiting ALDH-2. Hamster liver contains not only mitochondrial ALDH-2 but also high concentrations of a cytosolic form, ALDH-1, which is a very efficient catalyst of acetaldehyde oxidation. Further, the cytosolic isozyme is completely resistant to daidzin inhibition. This unusual property of the hamster ALDH-1 isozyme accounts for the fact we previously observed that daidzin can suppress ethanol intake of this species without blocking acetaldehyde metabolism. Thus, the mechanism by which daidzin suppresses ethanol intake in golden hamsters clearly differs from that proposed for the classic ALDH inhibitor disulfiram. We postulate that a physiological pathway catalyzed by ALDH-2, so far undefined, controls ethanol intake of golden hamsters and mediates the antidipsotropic effect of daidzin.

  19. Incoming College Students' Bystander Behaviors to Prevent Sexual Violence

    Science.gov (United States)

    McMahon, Sarah; Banyard, Victoria L.; McMahon, Sheila M.

    2015-01-01

    Evaluations of bystander intervention education programs demonstrate that this approach results in students' increased willingness to intervene in prosocial ways to prevent sexual violence (e.g., Moynihan, Banyard, Arnold, Eckstein, & Stapleton, 2010). These programs often focus on first-year college students, though theories and research on…

  20. A Qualitative Exploration of Cyber-Bystanders and Moral Engagement

    Science.gov (United States)

    Price, Deborah; Green, Deborah; Spears, Barbara; Scrimgeour, Margaret; Barnes, Alan; Geer, Ruth; Johnson, Bruce

    2014-01-01

    Studies have found that moral disengagement plays a significant role in the continuation of bullying situations (Bonanno, 2005); however, the moral stance of cyber-bystanders--those who witness online bullying--is not yet clear. While research into traditional face-to-face bullying reported that peers would probably or certainly intervene to…

  1. Elk3 from hamster-a ternary complex factor with strong transcriptional repressor activity

    DEFF Research Database (Denmark)

    Hjortoe, G.M.; Weilguny, D.; Willumsen, Berthe Marie

    2005-01-01

    the transcription of genes that are activated during entry into G1. We have isolated the Cricetulus griseus Elk3 gene from the Chinese hamster ovary (CHO) cell line and investigated the transcriptional potential of this factor. Transient transfections revealed that, in addition to its regulation of the c......-fos promoter, Elk3 from CHO cells seems to inhibit other promoters controlling expression of proteins involved in G1/S phase progression; Cyclin D1 and DHFR. As has been described for the Elk3 homologs Net (Mouse) and Sap-2 (Human), the results of the present study further indicate that hamster Elk3...

  2. Bystander T cells in human immune responses to dengue antigens

    Directory of Open Access Journals (Sweden)

    Suwannasaen Duangchan

    2010-09-01

    Full Text Available Abstract Background Previous studies of T cell activation in dengue infection have focused on restriction of specific T cell receptors (TCRs and classical MHC molecules. However, bystander T cell activation, which is TCR independent, occurs via cytokines in other viral infections, both in vitro and in vivo, and enables T cells to bypass certain control checkpoints. Moreover, clinical and pathological evidence has pointed to cytokines as the mediators of dengue disease severity. Therefore, we investigated bystander T cell induction by dengue viral antigen. Results Whole blood samples from 55 Thai schoolchildren aged 13-14 years were assayed for in vitro interferon-gamma (IFN-γ induction in response to inactivated dengue serotype 2 antigen (Den2. The contribution of TCR-dependent and independent pathways was tested by treatment with cyclosporin A (CsA, which inhibits TCR-dependent activation of T cells. ELISA results revealed that approximately 72% of IFN-γ production occurred via the TCR-dependent pathway. The major IFN-γ sources were natural killer (NK (mean ± SE = 55.2 ± 3.3, CD4+T (24.5 ± 3.3 and CD8+T cells (17.9 ± 1.5, respectively, as demonstrated by four-color flow cytometry. Interestingly, in addition to these cells, we found CsA-resistant IFN-γ producing T cells (CD4+T = 26.9 ± 3.6% and CD8+T = 20.3 ± 2.1% implying the existence of activated bystander T cells in response to dengue antigen in vitro. These bystander CD4+ and CD8+T cells had similar kinetics to NK cells, appeared after 12 h and were inhibited by anti-IL-12 neutralization indicating cytokine involvement. Conclusions This study described immune cell profiles and highlighted bystander T cell activation in response to dengue viral antigens of healthy people in an endemic area. Further studies on bystander T cell activation in dengue viral infection may reveal the immune mechanisms that protect or enhance pathogenesis of secondary dengue infection.

  3. Self-protective function of post-conflict bystander affiliation in mandrills.

    Directory of Open Access Journals (Sweden)

    Gabriele Schino

    Full Text Available BACKGROUND: Affiliative interactions exchanged between victims of aggression and individuals not involved in the original aggression (bystanders have been observed in various species. Three hypothetical functions have been proposed for these interactions: consolation, self-protection and substitute reconciliation, but data to test them are scanty. METHODOLOGY/PRINCIPAL FINDINGS: We conducted post-conflict and matched control observations on a captive group of mandrills (Mandrillus sphinx. We found that victims often redirected aggression to bystanders, that they received most affiliation from those bystanders that were frequently the target of redirection, and that bystander affiliation reduced the likelihood of redirection. Bystander affiliation did not reduce the victim's distress (as measured by its scratching rates and was not received primarily from kin/friends. Finally, bystander affiliation did not reduce the likelihood of renewed aggression from the original aggressor. CONCLUSIONS/SIGNIFICANCE: These results provide support for the self-protection hypothesis but not for the consolation and substitute reconciliation hypotheses.

  4. Role of ATM in bystander signaling between human monocytes and lung adenocarcinoma cells.

    Science.gov (United States)

    Ghosh, Somnath; Ghosh, Anu; Krishna, Malini

    2015-12-01

    The response of a cell or tissue to ionizing radiation is mediated by direct damage to cellular components and indirect damage mediated by radiolysis of water. Radiation affects both irradiated cells and the surrounding cells and tissues. The radiation-induced bystander effect is defined by the presence of biological effects in cells that were not themselves in the field of irradiation. To establish the contribution of the bystander effect in the survival of the neighboring cells, lung carcinoma A549 cells were exposed to gamma-irradiation, 2Gy. The medium from the irradiated cells was transferred to non-irradiated A549 cells. Irradiated A549 cells as well as non-irradiated A549 cells cultured in the presence of medium from irradiated cells showed decrease in survival and increase in γ-H2AX and p-ATM foci, indicating a bystander effect. Bystander signaling was also observed between different cell types. Phorbol-12-myristate-13-acetate (PMA)-stimulated and gamma-irradiated U937 (human monocyte) cells induced a bystander response in non-irradiated A549 (lung carcinoma) cells as shown by decreased survival and increased γ-H2AX and p-ATM foci. Non-stimulated and/or irradiated U937 cells did not induce such effects in non-irradiated A549 cells. Since ATM protein was activated in irradiated cells as well as bystander cells, it was of interest to understand its role in bystander effect. Suppression of ATM with siRNA in A549 cells completely inhibited bystander effect in bystander A549 cells. On the other hand suppression of ATM with siRNA in PMA stimulated U937 cells caused only a partial inhibition of bystander effect in bystander A549 cells. These results indicate that apart from ATM, some additional factor may be involved in bystander effect between different cell types.

  5. Vincristine-induced bystander effect in human lymphocytes

    Energy Technology Data Exchange (ETDEWEB)

    Testi, Serena; Azzarà, Alessia; Giovannini, Caterina; Lombardi, Sara [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Piaggi, Simona [Dipartimento di Ricerca Traslazionale e delle Nuove Tecnologie in Medicina e Chirurgia, Pisa University, Via Savi 10, 56126 Pisa (Italy); Facioni, Maria Sole [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Scarpato, Roberto, E-mail: roberto.scarpato@unipi.it [Unità di Genetica, Dipartimento di Biologia, Pisa University, Via Derna 1, 56126 Pisa (Italy); Research Center of Nutraceuticals and Food for Health, University of Pisa, Pisa (Italy)

    2016-07-15

    Highlights: • We studied whether or not vincristine induced a bystander response in human lymphocytes. • Vincristine significantly increased MN frequencies in mononucleated recipient cells. • ROS or soluble proteins (IL-32 and TGF-β) may account for the observed response. - Abstract: Bystander effect is a known radiobiological effect, widely described using ionizing radiations and which, more recently, has also been related to chemical mutagens. In this study, we aimed to assess whether or not a bystander response can be induced in cultured human peripheral lymphocytes by vincristine, a chemotherapeutic mutagen acting as spindle poison, and by mitomycin-C, an alkylating agent already known to induce this response in human lymphoblastoid cells. Designing a modified ad hoc protocol for the cytokinesis blocked micronucleus (MN) assay, we detected the presence of a dose-dependent bystander response in untreated cultures receiving the conditioned medium (CM) from mitomycin-C (MMC) or vincristine (VCR) treated cultures. In the case of MMC, MN frequencies, expressed as micronucleated binucleates, were: 13.5 ± 1.41 at 6 μM, 22 ± 2.12 at 12 μM or 28.25 ± 5.13 at 15 μM vs. a control value of 4.75 ± 1.59. MN levels for VCR, expressed as micronucleated mononucleates were: 2.75 ± 0.88 at 0.0 μM, 27.25 ± 2.30 at 0.4 μM, 46.25 ± 1.94 at 0.8 μM, 98.25 ± 7.25 at 1.6 μM. To verify that no mutagen residual was transferred to recipient cultures together with the CM, we evaluated MN levels in cultures receiving the medium immediately after three washings following the chemical treatment (unconditioned medium). We further confirmed these results using a cell-mixing approach where untreated lymphocytes were co-cultured with donor cells treated with an effect-inducing dose of MMC or VCR. A distinct production pattern of both reactive oxygen species and soluble mediator proteins by treated cells may account for the differences observed in the manifestation of the

  6. Do Sexual Assault Bystander Interventions Change Men's Intentions? Applying the Theory of Normative Social Behavior to Predicting Bystander Outcomes.

    Science.gov (United States)

    Mabry, Amanda; Turner, Monique Mitchell

    2016-01-01

    The high prevalence of sexual assault on college campuses has led to the implementation of health communication programs to prevent sexual assault. A few novel programs focus on primary prevention by targeting social norms related to gender and masculinity among men through bystander intervention. Guided by the theory of normative social behavior, this study sought to examine the relative effect of campaigns communicating positive versus negative injunctive norms and the interaction between exposure to such campaign messages and perceived descriptive norms and relevant cognitive moderators (e.g., outcome expectations, injunctive norms, group identity, ego involvement) among men. A 2 (high/low descriptive norms) × 2 (high/low moderator) × 3 (public service announcement) independent groups quasi-experimental design (N = 332) was used. Results indicated that messages communicating positive injunctive norms were most effective among men who were least likely to engage in bystander intervention. Furthermore, descriptive norms played a significant role in behavioral intentions, such that those with stronger norms were more likely to report intentions to engage in bystander behaviors in the future. Similarly, the moderators of aspiration, injunctive norms, social approval, and ego involvement had a significant positive effect on behavioral intentions. These findings have important implications for future message design strategy and audience segmentation.

  7. Involvement of MAPK proteins in bystander effects induced by chemicals and ionizing radiation

    Energy Technology Data Exchange (ETDEWEB)

    Asur, Rajalakshmi [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States); Balasubramaniam, Mamtha [Research Institute - Biostatistics, William Beaumont Hospital, 3911 W. Thirteen Mile Road, Royal Oak, MI 48073 (United States); Marples, Brian [Department of Radiation Oncology, William Beaumont Hospital, 3811 W. Thirteen Mile Road, Royal Oak, MI 48073 (United States); Thomas, Robert A. [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States); Tucker, James D., E-mail: jtucker@biology.biosci.wayne.edu [Department of Biological Sciences, Wayne State University, 5047 Gullen Mall, Suite 1370, Detroit, MI 48202-3917 (United States)

    2010-04-01

    Many studies have examined bystander effects induced by ionizing radiation, however few have evaluated the ability of chemicals to induce similar effects. We previously reported the ability of two chemicals, mitomycin C (MMC) and phleomycin (PHL) to induce bystander effects in normal human lymphoblastoid cell lines. The focus of the current study was to determine the involvement of the MAPK proteins in bystander effects induced by physical and chemical DNA damaging agents and to evaluate the effects of MAPK inhibition on bystander-induced caspase 3/7 activation. The phosphorylation levels of the MAPK proteins ERK1/2, JNK, and p38, were measured from 1 to 24 h following direct or bystander exposure to MMC, PHL or radiation. We observed transient phosphorylation, at early time points, of all 3 proteins in bystander cells. We also evaluated the effect of MAPK inhibition on bystander-induced caspase 3/7 activity to determine the role of MAPK proteins in bystander-induced apoptosis. We observed bystander-induced activation of caspase 3/7 in bystander cells. Inhibition of MAPK proteins resulted in a decrease in caspase 3/7 activity at the early time points, and the caspase activity increased (in the case of ERK inhibition) or returned to basal levels (in the case of JNK or p38 inhibition) between 12 and 24 h. PHL is considered to be a radiomimetic agent, however in the present study PHL behaved more like a chemical and not like radiation in terms of MAPK phosphorylation. These results point to the involvement of MAPK proteins in the bystander effect induced by radiation and chemicals and provide additional evidence that this response is not limited to radiation but is a generalized stress response in cells.

  8. Individual Motivations and Characteristics Associated with Bystander Intervention during Bullying Episodes among Children and Youth

    Science.gov (United States)

    Cappadocia, M. Catherine; Pepler, Debra; Cummings, Joanne G.; Craig, Wendy

    2012-01-01

    The aim of the current study was to explore bystander experiences during bullying episodes among children and youth attending a residential summer camp by investigating rates of witnessing and intervention, as well as individual motivations and characteristics associated with bystander intervention. The majority of children had witnessed bullying…

  9. What Would You Do? Strategies for Bystander Intervention to Prevent Sexual Violence by College Students

    Science.gov (United States)

    McMahon, Sarah; Hoffman, Melanie Lowe; McMahon, Sheila M.; Zucker, Sharon; Koenick, Ruth Anne

    2013-01-01

    Bystander education is an increasingly utilized strategy for addressing sexual assault prevention and intervention on U.S. college campuses. Given the paramount importance of peers among college students, what types of pro-social bystander interventions do students themselves deem feasible in the campus context? Drawing on self-reports from…

  10. Conceptualizing the Engaging Bystander Approach to Sexual Violence Prevention on College Campuses

    Science.gov (United States)

    McMahon, Sarah; Postmus, Judy L.; Koenick, Ruth Anne

    2011-01-01

    Bystander intervention offers promise as a sexual violence prevention tool for student affairs administrators on college campuses, but the conceptualization and definition of the approach is in its infancy and needs further development. In an effort to emphasize the potential role of bystanders in the primary prevention of sexual violence, we put…

  11. On Standby? A Comparison of Online and Offline Witnesses to Bullying and Their Bystander Behaviour

    Science.gov (United States)

    Quirk, Roslynn; Campbell, Marilyn

    2015-01-01

    Given their ubiquitous presence as witnesses to school-yard bullying, the role of the "bystander" has been studied extensively. The prevalence and behaviour of bystanders to "cyberbullying," however, is less understood. In an anonymous, school-based questionnaire, 716 secondary school students from South-East Queensland…

  12. Susceptibility to bystander DNA damage is influenced by replication and transcriptional activity.

    Science.gov (United States)

    Dickey, Jennifer S; Baird, Brandon J; Redon, Christophe E; Avdoshina, Valeriya; Palchik, Guillermo; Wu, Junfang; Kondratyev, Alexei; Bonner, William M; Martin, Olga A

    2012-11-01

    Direct cellular DNA damage may lead to genome destabilization in unexposed, bystander, cells sharing the same milieu with directly damaged cells by means of the bystander effect. One proposed mechanism involves double strand break (DSB) formation in S phase cells at sites of single strand lesions in the DNA of replication complexes, which has a more open structure compared with neighboring DNA. The DNA in transcription complexes also has a more open structure, and hence may be susceptible to bystander DSB formation from single strand lesions. To examine whether transcription predisposes non-replicating cells to bystander effect-induced DNA DSBs, we examined two types of primary cells that exhibit high levels of transcription in the absence of replication, rat neurons and human lymphocytes. We found that non-replicating bystander cells with high transcription rates exhibited substantial levels of DNA DSBs, as monitored by γ-H2AX foci formation. Additionally, as reported in proliferating cells, TGF-β and NO were found to mimic bystander effects in cell populations lacking DNA synthesis. These results indicate that cell vulnerability to bystander DSB damage may result from transcription as well as replication. The findings offer insights into which tissues may be vulnerable to bystander genomic destabilization in vivo.

  13. Measurement of the bystander intervention model for bullying and sexual harassment.

    Science.gov (United States)

    Nickerson, Amanda B; Aloe, Ariel M; Livingston, Jennifer A; Feeley, Thomas Hugh

    2014-06-01

    Although peer bystanders can exacerbate or prevent bullying and sexual harassment, research has been hindered by the absence of a validated assessment tool to measure the process and sequential steps of the bystander intervention model. A measure was developed based on the five steps of Latané and Darley's (1970) bystander intervention model applied to bullying and sexual harassment. Confirmatory factor analysis with a sample of 562 secondary school students confirmed the five-factor structure of the measure. Structural equation modeling revealed that all the steps were influenced by the previous step in the model, as the theory proposed. In addition, the bystander intervention measure was positively correlated with empathy, attitudes toward bullying and sexual harassment, and awareness of bullying and sexual harassment facts. This measure can be used for future research and to inform intervention efforts related to the process of bystander intervention for bullying and sexual harassment.

  14. Adolescent bystanders' perspectives of aggression in the online versus school environments.

    Science.gov (United States)

    Patterson, Lisa J; Allan, Alfred; Cross, Donna

    2016-06-01

    Researchers' understanding of bystanders' perspectives in the cyber-environment fails to take young people's perceptions into account and remains imperfect. Interventions encouraging adolescents to help targets of cyber-aggression are therefore typically based upon traditional school-based aggression research. Twenty-four in-depth interviews with Australian 13-16 year-olds revealed two themes that reflect how young bystanders perceive differences between aggression online and at school. The physical presence theme suggests that young bystanders struggle to determine online intentions in the absence of body language, leading to hesitancy in reactions and furthermore make it easier for them to ignore online transgressions and avoid becoming involved. The authority theme indicates young bystanders perceive that, compared to the school environment, the online environment lacks clearly established rules, authority figures and formal reporting mechanisms. These differences indicate that unique strategies should be developed to encourage young bystanders to intervene in cyber-aggression situations.

  15. Liver irradiation causes distal bystander effects in the rat brain and affects animal behaviour.

    Science.gov (United States)

    Kovalchuk, Anna; Mychasiuk, Richelle; Muhammad, Arif; Hossain, Shakhawat; Ilnytskyy, Slava; Ghose, Abhijit; Kirkby, Charles; Ghasroddashti, Esmaeel; Kovalchuk, Olga; Kolb, Bryan

    2016-01-26

    Radiation therapy can not only produce effects on targeted organs, but can also influence shielded bystander organs, such as the brain in targeted liver irradiation. The brain is sensitive to radiation exposure, and irradiation causes significant neuro-cognitive deficits, including deficits in attention, concentration, memory, and executive and visuospatial functions. The mechanisms of their occurrence are not understood, although they may be related to the bystander effects.We analyzed the induction, mechanisms, and behavioural repercussions of bystander effects in the brain upon liver irradiation in a well-established rat model.Here, we show for the first time that bystander effects occur in the prefrontal cortex and hippocampus regions upon liver irradiation, where they manifest as altered gene expression and somewhat increased levels of γH2AX. We also report that bystander effects in the brain are associated with neuroanatomical and behavioural changes, and are more pronounced in females than in males.

  16. Personal distress and the influence of bystanders on responding to an emergency.

    Science.gov (United States)

    Hortensius, Ruud; Schutter, Dennis J L G; de Gelder, Beatrice

    2016-08-01

    Spontaneous helping behavior during an emergency is influenced by the personality of the onlooker and by social situational factors such as the presence of bystanders. Here, we sought to determine the influences of sympathy, an other-oriented response, and personal distress, a self-oriented response, on the effect of bystanders during an emergency. In four experiments, we investigated whether trait levels of sympathy and personal distress predicted responses to an emergency in the presence of bystanders by using behavioral measures and single-pulse transcranial magnetic stimulation. Sympathy and personal distress were expected to be associated with faster responses to an emergency without bystanders present, but only personal distress would predict slower responses to an emergency with bystanders present. The results of a cued reaction time task showed that people who reported higher levels of personal distress and sympathy responded faster to an emergency without bystanders (Exp. 1). In contrast to our predictions, perspective taking but not personal distress was associated with slower reaction times as the number of bystanders increased during an emergency (Exp. 2). However, the decrease in motor corticospinal excitability, a direct physiological measure of action preparation, with the increase in the number of bystanders was solely predicted by personal distress (Exp. 3). Incorporating cognitive load manipulations during the observation of an emergency suggested that personal distress is linked to an effect of bystanders on reflexive responding to an emergency (Exp. 4). Taken together, these results indicate that the presence of bystanders during an emergency reduces action preparation in people with a disposition to experience personal distress.

  17. A role for bioelectric effects in the induction of bystander signals by ionizing radiation?

    Science.gov (United States)

    Mothersill, C; Moran, G; McNeill, F; Gow, M D; Denbeigh, J; Prestwich, W; Seymour, C B

    2007-04-03

    The induction of "bystander effects" i.e. effects in cells which have not received an ionizing radiation track, is now accepted but the mechanisms are not completely clear. Bystander effects following high and low LET radiation exposure are accepted but mechanisms are still not understood. There is some evidence for a physical component to the signal. This paper tests the hypothesis that bioelectric or biomagnetic phenomena are involved. Human immortalized skin keratinocytes and primary explants of mouse bladder and fish skin, were exposed directly to ionizing radiation or treated in a variety of bystander protocols. Exposure of cells was conducted by shielding one group of flasks using lead, to reduce the dose below the threshold of 2mGy (60)Cobalt gamma rays established for the bystander effect. The endpoint for the bystander effect in the reporter system used was reduction in cloning efficiency (RCE). The magnitude of the RCE was similar in shielded and unshielded flasks. When cells were placed in a Faraday cage the magnitude of the RCE was less but not eliminated. The results suggest that liquid media or cell-cell contact transmission of bystander factors may be only part of the bystander mechanism. Bioelectric or bio magnetic fields may have a role to play. To test this further, cells were placed in a Magnetic Resonance Imaging (MRI) machine for 10 min using a typical head scan protocol. This treatment also induced a bystander response. Apart from the obvious clinical relevance, the MRI results further suggest that bystander effects may be produced by non-ionizing exposures. It is concluded that bioelectric or magnetic effects may be involved in producing bystander signaling cascades commonly seen following ionizing radiation exposure.

  18. Daidzin inhibits mitochondrial aldehyde dehydrogenase and suppresses ethanol intake of Syrian golden hamsters

    OpenAIRE

    Keung, Wing Ming; Klyosov, Anatole A; Vallee, Bert L.

    1997-01-01

    Daidzin is the major active principle in extracts of radix puerariae, a traditional Chinese medication that suppresses the ethanol intake of Syrian golden hamsters. It is the first isoflavone recognized to have this effect. Daidzin is also a potent and selective inhibitor of human mitochondrial aldehyde dehydrogenase (ALDH-2). To establish a link between these two activities, we have tested a series of synthetic structural analogs of daidzin. The results demonstrate a direct correlation betwe...

  19. Protective Bystander Effects Simulated with the State-Vector Model

    OpenAIRE

    Schöllnberger, Helmut; Peter M. Eckl

    2007-01-01

    Apoptosis induced in non-hit bystander cells is an important biological mechanism which operates after exposure to low doses of low-LET radiation. This process was implemented into a deterministic multistage model for in vitro neoplastic transformation: the State-Vector Model (SVM). The new model is tested on two data sets that show a reduction of the transformation frequency below the spontaneous level after exposure of the human hybrid cell line CGL1 to low doses of γ-radiation. Stronger pr...

  20. 人源靶向补体抑制物CR2-CD59在中国仓鼠卵巢细胞中的稳定表达%Stable expression of targeting complement inhibitor CR2-CD59 in Chinese hamster ovary cells

    Institute of Scientific and Technical Information of China (English)

    郭彦; 周育森; 寇志华; 孙世惠; 张传福; 赵光宇; 于虹; 宋宏彬; 乔飞; 陈万荣

    2010-01-01

    目的 构建人源靶向补体抑制物CR2-CD59,并筛选中国仓鼠卵巢细胞(Chinese hamster ovary cell,CHO)高效表达细胞株. 方法 运用FuGENE 6转染试剂,将含有人CR2-CD59的重组PEE14.1质粒转入CHO细胞,蛋氨酸亚氨基代砜(MSX)筛选出阳性克隆,并利用无血清培养基对CHO细胞表达株进行培养获得重组蛋白,以ELISA、SDS-PAGE和Western blot对表达蛋白进行鉴定. 结果 成功构建PEE14.1-CR2-CD59重组质粒,获得CHO细胞稳定表达株.SDS-PAGE结果 表明,重组蛋白CR2-CD59的相对分子质量同预期结果 一致.ELISA和Western blot鉴定重组蛋白CR2-CD59可与CR2、CD59多克隆抗体特异性结合.且与含血清培养基相比,无血清培养基能明显提高CHO细胞的蛋白表达量(P<0.05).结论 在CHO细胞中成功表达人源靶向补体抑制物CR2-CD59.

  1. The development of bystander intentions and social-moral reasoning about intergroup verbal aggression.

    Science.gov (United States)

    Palmer, Sally B; Rutland, Adam; Cameron, Lindsey

    2015-11-01

    A developmental intergroup approach was taken to examine the development of prosocial bystander intentions among children and adolescents. Participants as bystanders (N = 260) aged 8-10 and 13-15 years were presented with scenarios of direct aggression between individuals from different social groups (i.e., intergroup verbal aggression). These situations involved either an ingroup aggressor and an outgroup victim or an outgroup aggressor and an ingroup victim. This study focussed on the role of intergroup factors (group membership, ingroup identification, group norms, and social-moral reasoning) in the development of prosocial bystander intentions. Findings showed that prosocial bystander intentions declined with age. This effect was partially mediated by the ingroup norm to intervene and perceived severity of the verbal aggression. However, a moderated mediation analysis showed that only when the victim was an ingroup member and the aggressor an outgroup member did participants become more likely with age to report prosocial bystander intentions due to increased ingroup identification. Results also showed that younger children focussed on moral concerns and adolescents focussed more on psychological concerns when reasoning about their bystander intention. These novel findings help explain the developmental decline in prosocial bystander intentions from middle childhood into early adolescence when observing direct intergroup aggression.

  2. Bystander effect induced by UV radiation; why should we be interested?

    Science.gov (United States)

    Widel, Maria

    2012-11-14

    The bystander effect, whose essence is an interaction of cells directly subjected to radiation with adjacent non-subjected cells, via molecular signals, is an important component of ionizing radiation action. However, knowledge of the bystander effect in the case of ultraviolet (UV) radiation is quite limited. Reactive oxygen and nitrogen species generated by UV in exposed cells induce bystander effects in non-exposed cells, such as reduction in clonogenic cell survival and delayed cell death, oxidative DNA damage and gene mutations, induction of micronuclei, lipid peroxidation and apoptosis. Although the bystander effect after UV radiation has been recognized in cell culture systems, its occurrence in vivo has not been studied. However, solar UV radiation, which is the main source of UV in the environment, may induce in human dermal tissue an inflammatory response and immune suppression, events which can be considered as bystander effects of UV radiation. The oxidative damage to DNA, genomic instability and the inflammatory response may lead to carcinogenesis. UV radiation is considered one of the important etiologic factors for skin cancers, basal- and squamous-cell carcinomas and malignant melanoma. Based on the mechanisms of actions it seems that the UV-induced bystander effect can have some impact on skin damage (carcinogenesis?), and probably on cells of other tissues. The paper reviews the existing data about the UV-induced bystander effect and discusses a possible implication of this phenomenon for health risk. 

  3. Risk Factors Associated with Peer Victimization and Bystander Behaviors among Adolescent Students

    Science.gov (United States)

    Huang, Zepeng; Liu, Zhenni; Liu, Xiangxiang; Lv, Laiwen; Zhang, Yan; Ou, Limin; Li, Liping

    2016-01-01

    Despite the prevalence of the phenomena of peer victimization and bystander behaviors, little data has generated to describe their relationships and risk factors. In this paper, a self-administered survey using a cross-sectional cluster-random sampling method in a sample of 5450 participants (2734 girls and 2716 boys) between 4th and 11th grades was conducted at six schools (two primary schools and four middle schools) located in Shantou, China. Self-reported peer victimization, bystander behaviors and information regarding parents’ risky behaviors and individual behavioral factors were collected. Multinomial logistic regression analysis was applied to evaluate risk factors affecting peer victimization and bystander behaviors. The results indicated that urban participants were more likely to become bullying victims but less likely to become passive bystanders. Contrarily, bullying victimization was related to the increasing of passive bystander behaviors. Father drinking and mother smoking as independent factors were risk factors for peer victimization. Participants who were smoking or drinking had a tendency to be involved in both peer victimization and passive bystander behaviors. This study suggested that bystander behaviors, victims’ and parents’ educations play a more important role in peer victimization than previously thought. PMID:27472354

  4. Prosocial Bystander Behavior in Bullying Dynamics: Assessing the Impact of Social Capital.

    Science.gov (United States)

    Evans, Caroline B R; Smokowski, Paul R

    2015-12-01

    Individuals who observe a bullying event, but are not directly involved as a bully or victim, are referred to as bystanders. Prosocial bystanders are those individuals who actively intervene in bullying dynamics to support the victim and this prosocial behavior often ends the bullying. The current study examines how social capital in the form of social support, community engagement, mental health functioning, and positive school experiences and characteristics is associated with the likelihood of engaging in prosocial bystander behavior in a large sample (N = 5752; 51.03% female) of racially/ethnically diverse rural youth. It was hypothesized that social capital would be associated with an increased likelihood of engaging in prosocial bystander behavior. Following multiple imputation, an ordered logistic regression with robust standard errors was run. The hypothesis was partially supported and results indicated that social capital in the form of friend and teacher support, ethnic identity, religious orientation, and future optimism were significantly associated with an increased likelihood of engaging in prosocial bystander behavior. Contrary to the hypothesis, a decreased rate of self-esteem was significantly associated with an increased likelihood of engaging in prosocial bystander behavior. The findings highlight the importance of positive social relationships and community engagement in increasing prosocial bystander behavior and ultimately decreasing school bullying. Implications were discussed.

  5. Induction of lyme arthritis in LSH hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, J.L.; Schell, R.F.; Hejka, A.; England, D.M.; Konick, L.

    1988-09-01

    In studies of experimental Lyme disease, a major obstacle has been the unavailability of a suitable animal model. We found that irradiated LSH/Ss Lak hamsters developed arthritis after injection of Borrelia burgdorferi in the hind paws. When nonirradiated hamsters were injected in the hind paws with B. burgdorferi, acute transient synovitis was present. A diffuse neutrophilic infiltrate involved the synovia and periarticular structures. The inflammation was associated with edema, hyperemia, and granulation tissue. Numerous spirochetes were seen in the synovial and subsynovial tissues. The histopathologic changes were enhanced in irradiated hamsters. The onset and duration of the induced swelling were dependent on the dose of radiation and the inoculum of spirochetes. Inoculation of irradiated hamsters with Formalin-killed spirochetes or medium in which B. burgdorferi had grown for 7 days failed to induce swelling. This animal model should prove useful for studies of the immune response to B. burgdorferi and the pathogenesis of Lyme arthritis.

  6. Polymyopathy in a Syrian golden hamster

    NARCIS (Netherlands)

    Wijnands, M.V.W.; Woutersen, R.A.

    1996-01-01

    A Syrian golden hamster suffered from general swelling of skeletal muscles. At microscopical observation the muscle tissue exhibited degeneration and necrosis, as well as regenerative features. The inflammatory response was very slight. The histopathological lesions were diagnosed as polymyopathy.

  7. Bystanders' Behavior in Cyberbullying Episodes: Active and Passive Patterns in the Context of Personal-Socio-Emotional Factors.

    Science.gov (United States)

    Olenik-Shemesh, Dorit; Heiman, Tali; Eden, Sigal

    2017-01-01

    The present study explored bystanders' behavior in cyberbullying (CB) episodes among children and youth, focusing on active and passive behavior patterns. The study examined prevalence and characteristics of bystanders' behavior following CB episodes, and their active-passive intervention patterns in relation to personal (age, gender) and socio-emotional (self-efficacy, social support, sense of loneliness) factors. Of the 1,094 participants (ages 9-18), 497 (46.4%) reported they were bystanders to CB episodes. Of the bystanders, 55.4% were identified as having a passive pattern of behavior-they did not provide any help to cyber-victims, whereas 44.6% were identified as having an active pattern-helping the cyber-victim. In line with the "bystanders' effect," only 35.6% of the bystanders offered direct help to cyber-victims after witnessing CB. When studying the personal-socio-emotional differences between active and passive bystanders, it was found that the "active bystanders" are more often girls, older, have more social support from significant others, and have lower levels of emotional loneliness than bystanders in the passive group. Differences within the passive and active patterns were studied as well. A logistic regression revealed the unique contribution of each predictor to the probability of being an active bystander. It was found that gender and age predicted the probability of being an active bystander: Girls are more likely than boys, and older bystanders are more likely than younger ones, to choose an active pattern and provide help to cyber-victims. In addition, implications for CB prevention and intervention involvement programs to encourage bystanders to help cyber-victims are discussed.

  8. Heart rate modulation in bystanding geese watching social and non-social events

    NARCIS (Netherlands)

    Wascher, Claudia A. F.; Scheiber, Isabella B. R.; Kotrschal, Kurt

    2008-01-01

    Simply observing other individuals interacting has been shown to affect subsequent behaviour and also hormones in 'bystander' individuals. However, immediate physiological responses of an observer have been hardly investigated. Here we present results on individuals' heart rate (HR) responses during

  9. Effects of manipulated aggressive 'interactions' on bystanding male fighting fish, Betta splendens

    DEFF Research Database (Denmark)

    Peake, Thomas More; Matos, Ricardo Jorge; McGregor, Peter Kenneth

    2006-01-01

    Aggressive interactions between animals often take place in a social environment. Third parties not involved in those interactions, bystanders, have the opportunity to extract information from such interactions and such information may direct their future behaviour towards the interactants. Studi...

  10. Morbidity among bystanders of bullying behavior at school: concepts, concerns, and clinical/research issues.

    Science.gov (United States)

    Rivers, Ian

    2011-11-04

    The role of the bystander is not one that is easily understood in the anti-bullying literature. Roles within the unofficial hierarchy of the school-yard and playground overlap considerably, and each role has its own social dynamic that brings with it a shifting behavioral landscape that affects every student. In this article, the mental health correlates of three categories of bystander are explored: the co-victim, the isolate, and the confederate. Each category of bystander has its own characterizations and mental health correlates. Reports of post-traumatic stress, internalized hostility, substance use, and suicide ideation are discussed with reference to studies involving witnesses of family abuse, community and school violence as well as bullying. It is argued that bystanders are the key to challenging bullying in schools, and their mental health and well-being is pivotal to the effectiveness of anti-bullying interventions.

  11. The Effect of a Class-wide Training on Prosocial Bystander Behaviors

    OpenAIRE

    Barnes, Charity Deanne

    2015-01-01

    The purpose of this study was to decrease school bullying by implementing a class-wide intervention that targets bystanders. Hypotheses include that an intervention will increase prosocial bystander behaviors that will result in reduced rates of bullying and improved positive peer responses. Ross and Horner’s Positive Behavior Supports bullying prevention program was modified to increase incentives for students who defend others from bullying. A multiple baseline design across three general e...

  12. Autophagy promotes radiation-induced senescence but inhibits bystander effects in human breast cancer cells.

    Science.gov (United States)

    Huang, Yao-Huei; Yang, Pei-Ming; Chuah, Qiu-Yu; Lee, Yi-Jang; Hsieh, Yi-Fen; Peng, Chih-Wen; Chiu, Shu-Jun

    2014-07-01

    Ionizing radiation induces cellular senescence to suppress cancer cell proliferation. However, it also induces deleterious bystander effects in the unirradiated neighboring cells through the release of senescence-associated secretory phenotypes (SASPs) that promote tumor progression. Although autophagy has been reported to promote senescence, its role is still unclear. We previously showed that radiation induces senescence in PTTG1-depleted cancer cells. In this study, we found that autophagy was required for the radiation-induced senescence in PTTG1-depleted breast cancer cells. Inhibition of autophagy caused the cells to switch from radiation-induced senescence to apoptosis. Senescent cancer cells exerted bystander effects by promoting the invasion and migration of unirradiated cells through the release of CSF2 and the subsequently activation of the JAK2-STAT3 and AKT pathways. However, the radiation-induced bystander effects were correlated with the inhibition of endogenous autophagy in bystander cells, which also resulted from the activation of the CSF2-JAK2 pathway. The induction of autophagy by rapamycin reduced the radiation-induced bystander effects. This study reveals, for the first time, the dual role of autophagy in radiation-induced senescence and bystander effects.

  13. Bystanders' responses to offline bullying and cyberbullying: The role of empathy and normative beliefs about aggression.

    Science.gov (United States)

    Machackova, Hana; Pfetsch, Jan

    2016-04-01

    Cyberbullying often takes place with the virtual presence or knowledge of bystanders. While we have some evidence about the determinants of bystanders' responses to offline bullying, we lack empirical studies concerning the variables that influence bystanders' responses to cyberbullying. The current study examines bystanders' responses to offline bullying and cyberbullying incidents. Two types of responses were captured: support toward the victims and the reinforcement of bullies' actions. Using data from 321 German adolescents (ages 12-18; M = 14.99; 44% girls), the association between bystanders' responses and normative beliefs about verbal aggression and cyberaggression, and affective and cognitive empathy, were tested in a path model. Both types of normative beliefs positively predicted the reinforcement of bullies, and normative belief about verbal aggression also predicted support for the victims of offline bullying. Both types of empathy predicted support in offline bullying, but only affective empathy predicted support in cyberbullying. There was no link between affective or cognitive empathy to the reinforcement of bullies. Moreover, bystanders' tendencies to respond supportively to the victim or to reinforce the bully were rather consistent in both cyber- and offline bullying, but there was no link between support and reinforcement. The findings are discussed with regard to implications for prevention and intervention efforts.

  14. Determinants of self-reported bystander behavior in cyberbullying incidents amongst adolescents.

    Science.gov (United States)

    DeSmet, Ann; Veldeman, Charlene; Poels, Karolien; Bastiaensens, Sara; Van Cleemput, Katrien; Vandebosch, Heidi; De Bourdeaudhuij, Ilse

    2014-04-01

    This study explores behavioral determinants of self-reported cyberbullying bystander behavior from a behavioral change theoretical perspective, to provide levers for interventions. Nine focus groups were conducted with 61 young adolescents (aged 12-16 years, 52% girls). Assertive defending, reporting to others, providing advice, and seeking support were the most mentioned behaviors. Self-reported bystander behavior heavily depended on contextual factors, and should not be considered a fixed participant role. Bystanders preferred to handle cyberbullying offline and in person, and comforting the victim was considered more feasible than facing the bully. Most prevailing behavioral determinants to defend or support the victim were low moral disengagement, that the victim is an ingroup member, and that the bystander is popular. Youngsters felt they received little encouragement from their environment to perform positive bystanding behavior, since peers have a high acceptance for not defending and perceived parental support for defending behavior is largely lacking. These results suggest multilevel models for cyberbullying research, and interventions are needed. With much previous research into cyberbullying insufficiently founded in theoretical models, the employed framework of the Integrative Model and Social Cognitive Theory may inspire future studies into bystander behavior.

  15. 胞外唾液酸酶造成工程中国仓鼠卵巢细胞株所产人源重组促红素唾液酸含量降低%Extracellular sialidase degrades sialic acid in recombinant human erythropoietin produced by an industrial Chinese hamster ovary cell strain

    Institute of Scientific and Technical Information of China (English)

    刘颖慰; 周祥山; 刘海峰; 宋志伟; 张元兴

    2012-01-01

    To investigate the N-glycosylation characteristics of recombinant human erythropoietin (rhEPO) produced by an industrial Chinese hamster ovary (CHO) cell line that is currently used in a large scale manufacturing process, we cultured this cell strain in static mode. The produced rhEPO in the culture supernatant was analyzed using isoelectric focusing (IEF) and Ricinus communis agglutinin-I (RCA-I) lectin precipitation. The lactate dehydrogenase (LDH) and sialidase activity in the serum-free supernatant were assayed as well. The analyses revealed that this cell strain could produce rhEPO with high sialic acid content, but during prolonged culture, cell viability decreased with time whilst the activity of sialidase present in the supernatant increased. The loss in rhEPO quality was due to a decrease in terminal sialic acid on the N-glycans, caused by sialidase degradation. The methods and findings in this paper serve as basis for further investigation of industrial production process.%为了对工程中国仓鼠卵巢(CHO)细胞所产人源重组促红素(rhEPO)的N-糖基化特点进行考察,静置培养工程细胞后,通过等电聚焦和凝集素共沉淀对培养上清中的rhEPO进行分析,并对无血清培养上清中乳酸脱氢酶(LDH)和唾液酸酶活性进行检测,发现这株CHO细胞可以表达唾液酸含量较高的rhEPO蛋白.但是随着培养时间的延长,细胞的存活率逐渐降低,死亡的细胞将胞内的唾液酸酶释放到胞外,唾液酸酶的降解作用会造成N-糖链分枝末端的唾液酸占有率降低,导致rhEPO蛋白糖基化形态的变化.所使用的方法及得到的结果为进一步对工业过程进行分析提供了参考.

  16. Critical role of gap junction communication, calcium and nitric oxide signaling in bystander responses to focal photodynamic injury.

    Science.gov (United States)

    Calì, Bianca; Ceolin, Stefano; Ceriani, Federico; Bortolozzi, Mario; Agnellini, Andrielly H R; Zorzi, Veronica; Predonzani, Andrea; Bronte, Vincenzo; Molon, Barbara; Mammano, Fabio

    2015-04-30

    Ionizing and nonionizing radiation affect not only directly targeted cells but also surrounding "bystander" cells. The underlying mechanisms and therapeutic role of bystander responses remain incompletely defined. Here we show that photosentizer activation in a single cell triggers apoptosis in bystander cancer cells, which are electrically coupled by gap junction channels and support the propagation of a Ca2+ wave initiated in the irradiated cell. The latter also acts as source of nitric oxide (NO) that diffuses to bystander cells, in which NO levels are further increased by a mechanism compatible with Ca(2+)-dependent enzymatic production. We detected similar signals in tumors grown in dorsal skinfold chambers applied to live mice. Pharmacological blockade of connexin channels significantly reduced the extent of apoptosis in bystander cells, consistent with a critical role played by intercellular communication, Ca2+ and NO in the bystander effects triggered by photodynamic therapy.

  17. Effects of berberine on expression of hepatic peroxisome proliferator-activated receptors and its target genes in type 2 diabetic Chinese hamsters%2型糖尿病中国地鼠模型构建与小檗碱对肝脏过氧化物酶体增殖体激活受体及其靶基因表达的影响

    Institute of Scientific and Technical Information of China (English)

    刘栩晗; 李国生; 黄澜; 朱华; 刘亚莉; 马春梅

    2011-01-01

    BACKGROUND: Although Berberine has been reported to treat type 2 diabetes, the underlying mechanisms of berberine on insulin resistance of type 2 diabetes, especially hepatic insulin resistance, remains not fully understood.OBJECTIVE: To study the effects of berberine on the expression of hepatic peroxisome proliferator-activated receptors (PPARs) and their target genes in type 2 diabetic Chinese hamsters.METHODS: The insulin-resistant and type 2 diabetic Chinese hamster models were induced by high-fat diet without or with low-dose streptozotocin. After the induction of models, the hamsters were randomly divided into normal control (standard food),insulin-resistant (high-fat diet), diabetic (high-fat diet and streptozotocin) and berberine-treated diabetic (high-fat diet and streptozotocin and berberine) groups. All groups were treated for 9 weeks.RESULTS AND CONCLUSION: Results of real-time quantitative PCR indicated that compared with normal control group, the expression of PPARα, PPARβ/δ, acyl-Coenzyme A oxidase (Acox), carnitine palmitoyltransferase 1 (Cpt1) and acetyl-Coenzyme A dehydrogenase, medium chain (Acadm) was decreased (P < 0.05) and the expression of sterol regulatory element binding factor 1 (SREBP1c), sterol regulatory element binding factor 2 (SREBP2), PPARγ, lipoprotein lipase (LPL), CD36/FA transporter (FAT/CD36) and adipocyte fatty acid-binding protein (ap2) was increased (P < 0.05) in the fatty liver of insulin-resistant and diabetic hamster groups. Berberine effectively improved insulin resistance, reversed the altered expression of PPARs and its target genes in diabetic hamsters. PPARs and its target genes involved in the therapeutic molecular mechanisms of berberine on fat-induced hepatic insulin resistance in type 2 diabetic hamsters.%背景:研究表明小檗碱可用于治疗2型糖尿病,但小檗碱治疗糖尿病胰岛素抵抗尤其是肝脏脂诱性胰岛素抵抗的分子机制仍不明确.目的:观察小檗碱对2型糖

  18. Histopathology of Lyme arthritis in LSH hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Hejka, A.; Schmitz, J.L.; England, D.M.; Callister, S.M.; Schell, R.F.

    1989-05-01

    The authors studied the histopathologic evolution of arthritis in nonirradiated and irradiated hamsters infected with Borrelia burgdorferi. Nonirradiated hamsters injected in the hind paws with B. burgdorferi developed an acute inflammatory reaction involving the synovium, periarticular soft tissues, and dermis. This acute inflammatory reaction was short-lived and was replaced by a mild chronic synovitis as the number of detectable spirochetes in the synovium, periarticular soft tissues, and perineurovascular areas diminished. Exposing hamsters to radiation before inoculation with B. burgdorferi exacerbated and prolonged the acute inflammatory phase. Spirochetes also persisted longer in the periarticular soft tissues. A major histopathologic finding was destructive and erosive bone changes of the hind paws, which resulted in deformation of the joints. These studies should be helpful in defining the immune mechanism participating in the onset, progression, and resolution of Lyme arthritis.

  19. Contribution to the normal fecal flora of the hamster: Proteus mirabilis in normal feces of hamster

    Directory of Open Access Journals (Sweden)

    Genesio Pacheco

    1955-05-01

    Full Text Available Proteus mirabilis must be considered a normal inhabitant of the intestine of hamsters. It is also found in the vaginal secretion of females of this animal, when in oestrus.1 Os hamsters são parasitados pelos Proteus. 2 As amostras isoladas foram identificadas ao Pr. mirabilis de Hauser. 3 O Proteus isolado não revelou ação patogênica sôbre camundongos mas se mostrou patogênico para cobaias. 4 O germen era presente na secreção vaginal de hamsters, na época do cio.

  20. An extracellular DNA mediated bystander effect produced from low dose irradiated endothelial cells

    Energy Technology Data Exchange (ETDEWEB)

    Ermakov, Aleksei V., E-mail: avePlato@mail.ru [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation); Konkova, Marina S.; Kostyuk, Svetlana V.; Smirnova, Tatiana D.; Malinovskaya, Elena M.; Efremova, Liudmila V.; Veiko, Natalya N. [Research Centre for Medical Genetics, Russian Academy of Medical Sciences, Moscow (Russian Federation)

    2011-07-01

    The human umbilical vein endothelial cells culture was exposed to X-ray radiation in a low dose of 10 cGy. The fragments of extracellular genomic DNA (ecDNA{sup R}) were isolated from the culture medium after the short-term incubation. A culture medium of unirradiated endothelial cells was then supplemented with ecDNA{sup R}, followed by analysing the cells along the series of parameters (bystander effect). The exposed cells and bystander endotheliocytes showed similar response to low doses: approximation of the 1q12 loci of chromosome 1 and their transposition into the cellular nucleus, change in shape of the endotheliocytic nucleus, activation of the nucleolus organizing regions (NORs), actin polymerization, and an elevated level of DNA double-stranded breaks. Following blockade of TLR9 receptors with oligonucleotide-inhibitor or chloroquine in the bystander cells these effects - except of activation of NORs - on exposure to ecDNA{sup R} disappeared, with no bystander response thus observed. The presence of the radiation-induced apoptosis in the bystander effect being studied suggests a possibility for radiation-modified ecDNA fragments (i.e., stress signaling factors) to be released into the culture medium, whereas inhibition of TLR9 suggests the binding these ligands to the recipient cells. A similar DNA-signaling pathway in the bystander effect we previously described for human lymphocytes. Integrity of data makes it possible to suppose that a similar signaling mechanism which we demonstrated for lymphocytes (humoral system) might also be mediated in a monolayer culture of cells (cellular tissue) after the development of the bystander effect in them and transfer of stress signaling factors (ecDNA{sup R}) through the culture medium.

  1. Target irradiation induced bystander effects between stem-like and non stem-like cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Yu [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Kobayashi, Alisa [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Maeda, Takeshi [Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Fu, Qibin [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Oikawa, Masakazu [Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Yang, Gen, E-mail: gen.yang@pku.edu.cn [State Key Laboratory of Nuclear Physics and Technology, School of Physics, Peking University, Beijing 100871 (China); Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Konishi, Teruaki, E-mail: tkonishi@nirs.go.jp [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Uchihori, Yukio [Space Radiation Research Unit, International Open Laboratory, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); Department of Technical Support and Development, National Institute of Radiological Sciences, 4-9-1 Inage-ku, Chiba 263-8555 (Japan); and others

    2015-03-15

    Highlights: • Existence of radiation induced bystander effects (RIBE) between cancer stem-like cells (CSCs) and non stem-like cancer cells (NSCCs) in human fibrosarcoma HT1080 cells. • Existence of significant difference in generation and response of bystander signals between CSCs and NSCCs. • CSCs are significantly less sensitive to NO scavenger than that of NSCCs in terms of DNA double strand breaks induced by RIBE. - Abstract: Tumors are heterogeneous in nature and consist of multiple cell types. Among them, cancer stem-like cells (CSCs) are suggested to be the principal cause of tumor metastasis, resistance and recurrence. Therefore, understanding the behavior of CSCs in direct and indirect irradiations is crucial for clinical radiotherapy. Here, the CSCs and their counterpart non stem-like cancer cells (NSCCs) in human HT1080 fibrosarcoma cell line were sorted and labeled, then the two cell subtypes were mixed together and chosen separately to be irradiated via a proton microbeam. The radiation-induced bystander effect (RIBE) between the CSCs and NSCCs was measured by imaging 53BP1 foci, a widely used indicator for DNA double strand break (DSB). CSCs were found to be less active than NSCCs in both the generation and the response of bystander signals. Moreover, the nitric oxide (NO) scavenger c-PTIO can effectively alleviate the bystander effect in bystander NSCCs but not in bystander CSCs, indicating a difference of the two cell subtypes in NO signal response. To our knowledge, this is the first report shedding light on the RIBE between CSCs and NSCCs, which might contribute to a further understanding of the out-of-field effect in cancer radiotherapy.

  2. Bystander Sexual Violence Prevention Program: Outcomes for High- and Low-Risk University Men.

    Science.gov (United States)

    Elias-Lambert, Nada; Black, Beverly M

    2015-05-05

    This research reports the findings of an evaluation of a peer-facilitated, bystander sexual violence prevention program to determine its effectiveness at changing attitudes and behaviors related to sexual violence with university males who are at low- and high-risk of using sexually coercive behavior. Bystander interventions focus on men and women as bystanders to change social norms in a peer culture that supports abusive behaviors. Few studies have examined the effectiveness of these interventions with high-risk populations, which is the focus of this study. A bystander sexual violence prevention program was presented to 142 fraternity members. A quasi-experimental design utilizing pre-, post-, and follow-up surveys was used to compare the effectiveness of this prevention program with university males who are at low- and high-risk of using sexually coercive behavior in intervention and comparison groups. Participants' risk status was measured prior to the intervention using the Modified-Sexual Experiences Survey. The measures evaluated changes in attitudes (rape myth acceptance and bystander attitudes) and behaviors (sexually coercive behaviors, sexually coercive behavioral intentions, and bystander behaviors). Data analyses included Repeated-Measures Analysis of Covariances. The findings suggest that a bystander sexual violence prevention program has a positive impact on attitudes and behaviors related to sexual violence among fraternity members, however, the program had less impact on high-risk males. The results of this study will expand our ability to design programs that can have an impact on reducing sexual violence on campus by ensuring the programs are having the desired impact on the target audience.

  3. Ion beam induced luminescence: Relevance to radiation induced bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Ahmad, S.B., E-mail: ahmad.rabilal@gmail.com [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); McNeill, F.E., E-mail: fmcneill@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Byun, S.H., E-mail: soohyun@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Prestwich, W.V., E-mail: prestwic@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Seymour, C., E-mail: seymouc@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada); Mothersill, C.E., E-mail: mothers@mcmaster.ca [Medical Physics and Applied Radiation Sciences, University of McMaster, Hamilton, Ontario (Canada)

    2012-10-01

    The aim of this work is quantify the light emitted as a result of charged particle interaction in materials which may be of relevance to radiation induced 'bystander effects' studies. We have developed a system which employs single photon counting to measure the light emitted from samples irradiated under vacuum by a charged particle beam. The system uses a fast photomultiplier tube with a peak cathode response at 420 nm. It has been tested in a proof-of-principle experiment using polystyrene targets. Light output, as a result of irradiation, was measured. The luminescence yield appears to have a non-linear behavior with the incident ion fluence: it rises exponentially to an asymptotic value. The target was irradiated with beam energies varying from 1 to 2 MeV and showed saturation at or before an incident fluence rate of 3 Multiplication-Sign 10{sup 13} H{sup +}/cm{sup 2} s. The average saturation value for the photon output was found to be 40 Multiplication-Sign 10{sup 6} cps. Some measurements were performed using filters to study the emission at specific wavelengths. In the case of filtered light measurements, the photon output was found to saturate at 28 Multiplication-Sign 10{sup 3}, 10 Multiplication-Sign 10{sup 6}, and 35 Multiplication-Sign 10{sup 6} cps for wavelengths of 280 {+-} 5 nm, 320 {+-} 5 nm and 340 {+-} 5 nm respectively. The light output reaches a maximum value because of damage induced in the polymer. Our measurements indicate a 'damage cross section' of the order of 10{sup -14} cm{sup 2}. The average radiant intensity was found to increase at wavelengths of 280 and 320 nm when the proton energy was increased. This was not found to occur at 340 nm. In conclusion, the light emission at specific wavelengths was found to depend upon the incident proton fluence and the proton energy. The wavelengths of the emitted light measured in this study have significance for the understanding of radiation induced bystander effects.

  4. Ahne hamster lõikuskuul/ Tambet Kaugema

    Index Scriptorium Estoniae

    Kaugema, Tambet

    2010-01-01

    Eesti Nuku- ja Noorsoteatri jõululavastusest "Ahne hamster ja värvilised jäälilled", autor Miloš Macourek, tõlkija Leo Metsar, lavastaja ja muusikaline kujundaja Virko Annus, mängib Tarmo Männard. Esietendus 21. novembril Köismäe tornis

  5. Booze, Bars, and Bystander Behavior: People Who Consumed Alcohol Help Faster in the Presence of Others.

    Science.gov (United States)

    van Bommel, Marco; van Prooijen, Jan-Willem; Elffers, Henk; Van Lange, Paul A M

    2016-01-01

    People help each other less often and less quickly when bystanders are present. In this paper, we propose that alcohol consumption could attenuate or reverse this so-called bystander effect. Alcohol impairs people cognitively and perceptually, leading them to think less about the presence of others and behave less inhibited. Moreover, alcohol makes people more prone to see the benefits of helping and not the costs. To provide an initial test of these lines of reasoning, we invited visitors of bars in Amsterdam to join our study at a secluded spot at the bar. We manipulated bystander presence, and at the end of the study, we measured alcohol consumption. When participants took their seats, the experimenter dropped some items. We measured how many items were picked up and how quickly participants engaged in helping. Results revealed that alcohol did not influence the bystander effect in terms of the amount of help given. But importantly, it did influence the bystander effect in terms of response times: people who consumed alcohol actually came to aid faster in the presence of others.

  6. Booze, Bars, and Bystander Behavior: People who Consumed Alcohol Help Faster in the Presence of Others.

    Directory of Open Access Journals (Sweden)

    Marco eVan Bommel

    2016-02-01

    Full Text Available People help each other less often and less quickly when bystanders are present. In this paper, we propose that alcohol consumption could attenuate or reverse this so-called bystander effect. Alcohol impairs people cognitively and perceptually, leading them to think less about the presence of others and behave less inhibited. Moreover, alcohol makes people more prone to see the benefits of helping and not the costs. To provide an initial test of these lines of reasoning, we invited visitors of bars in Amsterdam to join our study at a secluded spot at the bar. We manipulated bystander presence, and at the end of the study, we measured alcohol consumption. When participants took their seats, the experimenter dropped some items. We measured how many items were picked up and how quickly participants engaged in helping. Results revealed that alcohol did not influence the bystander effect in terms of the amount of help given. But importantly, it did influence the bystander effect in terms of response times: People who consumed alcohol actually came to aid faster in the presence of others.

  7. Proteome analysis of proliferative response of bystander cells adjacent to cells exposed to ionizing radiation.

    Science.gov (United States)

    Gerashchenko, Bogdan I; Yamagata, Akira; Oofusa, Ken; Yoshizato, Katsutoshi; de Toledo, Sonia M; Howell, Roger W

    2007-06-01

    Recently (Cytometry 2003, 56A, 71-80), we reported that direct cell-to-cell contact is required for stimulating proliferation of bystander rat liver cells (WB-F344) cocultured with irradiated cells, and neither functional gap junction intercellular communication nor long-range extracellular factors appear to be involved in this proliferative bystander response (PBR). The molecular basis for this response is unknown. Confluent monolayers of WB-F344 cells were exposed to 5-Gray (Gy) of gamma-rays. Irradiated cells were mixed with unirradiated cells and co-cultured for 24 h. Cells were harvested and protein expression was examined using 2-DE. Protein expression was also determined in cultures of unirradiated and 5-Gy irradiated cells. Proteins were identified by MS. Nucleophosmin (NPM)-1, a multifunctional nucleolar protein, was more highly expressed in bystander cells than in either unirradiated or 5-Gy irradiated cells. Enolase-alpha, a glycolytic enzyme, was present in acidic and basic variants in unirradiated cells. In bystander and 5-Gy irradiated cells, the basic variant was weakly expressed, whereas the acidic variant was overwhelmingly present. These data indicate that the presence of irradiated cells can affect NPM-1 and enolase-alpha in adjacent bystander cells. These proteins appear to participate in molecular events related to the PBR and suggest that this response may involve cellular defense, proliferation, and metabolism.

  8. Rescue effects in radiobiology: Unirradiated bystander cells assist irradiated cells through intercellular signal feedback

    Energy Technology Data Exchange (ETDEWEB)

    Chen, S. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Zhao, Y. [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Han, W. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Chiu, S.K. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Zhu, L. [Office of Admission and Careers Advisory Service, Shenzhen University, Shenzhen 518060 (China); Wu, L. [Key Laboratory of Ion Beam Bioengineering, Institute of Plasma Physics, Chinese Academy of Sciences, Hefei 230031 (China); Yu, K.N., E-mail: peter.yu@cityu.edu.hk [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2011-01-10

    Mammalian cells respond to ionization radiation by sending out extracellular signals to affect non-irradiated neighboring cells, which is referred to as radiation induced bystander effect. In the present paper, we described a phenomenon entitled the 'rescue effects', where the bystander cells rescued the irradiated cells through intercellular signal feedback. The effect was observed in both human primary fibroblast (NHLF) and cancer cells (HeLa) using two-cell co-culture systems. After co-culturing irradiated cells with unirradiated bystander cells for 24 h, the numbers of 53BP1 foci, corresponding to the number of DNA double-strand breaks in the irradiated cells were less than those in the irradiated cells that were not co-cultured with the bystander cells (0.78 {+-} 0.04 foci/cell vs. 0.90 {+-} 0.04 foci/cell) at a statistically significant level. Similarly, both micronucleus formation and extent of apoptosis in the irradiated cells were different at statistically significant levels if they were co-cultured with the bystander cells. Furthermore, it was found that unirradiated normal cells would also reduce the micronucleus formation in irradiated cancer cells. These results suggested that the rescue effects could participate in repairing the radiation-induced DNA damages through a media-mediated signaling feedback, thereby mitigating the cytotoxicity and genotoxicity of ionizing radiation.

  9. Caspase-3-independent pathways proceeding in bystander effect of HSV-tk/GCV system

    Science.gov (United States)

    Lin, Juqiang; Ma, Yan; Zeng, Shaoqun; Zhang, Zhihong

    2008-02-01

    HSV-tk/GCV system, which is the virus-directed enzyme/prodrug therapy of herpes simplex virus (HSV) thymidine kinase (tk) gene / the anti-viral reagent ganciclovir (GCV), is one of the promising approaches in the rapidly growing area of gene therapy. As gene therapy of cancer such as suicide gene therapy has entered the clinic, another therapy effect which is called 'bystander effect' was reported. Bystander effect can lead to killing of non-transduced tumor cells in the immediate vicinity of GCV-treated HSV-TK-positive cells. Now the magnitude of 'bystander effect' is an essential factor for this anti-tumor approach in vivo. However, the mechanism which HSV-tk/ACV brings "bystander effect" is poorly understood. In this study, we monitor the activation of caspase-3 in HSV-tk/GCV system by a FRET probe CD3, a FRET-based indicator for activity of caspase3, which is composed of an enhanced cyan fluorescent protein, a caspase-sensitive linker, and a red fluorescent protein from Discosoma with efficient maturation property. Through application of CD3 we have visualized the activation of caspase-3 in tk gene positive human adenoid cystic carcinoma (ACC-M) cells but not in bystander effect of HSV-tk/GCV system induced by GCV. This finding provides needed information for understanding the mechanisms by which suicide gene approaches actually kill cancer cells, and may prove to be helpful for the clinical treatment of cancers.

  10. A Longitudinal Study of the Associations between Moral Disengagement and Active Defending versus Passive Bystanding during Bullying Situations

    Science.gov (United States)

    Doramajian, Caroline; Bukowski, William M.

    2015-01-01

    This study investigated the prospective association between moral disengagement and bystander behaviors in bullying situations, including both defending and passive bystanding. A diverse sample of Canadian school children (N = 130; 68 boys and 62 girls; mean age = 11.36 years) participated in a three-wave longitudinal study over a 4-month period.…

  11. Contamination of genetically engineered Chinese hamster ovary cells.

    Science.gov (United States)

    Burstyn, D G

    1996-01-01

    In late 1988, during production of a recombinant protein for phase I clinical trials, a failure of the cell culture production system occurred due to contamination of the cells by an orbivirus [1]. The incident occurred at Bioferon GmbH & Co, Laupheim, Germany, a joint venture of Biogen, Inc., Cambridge, MA, and Dr. Renstschler Arzneimittel GmbH & Co (Bioferon is currently a wholly owned subsidiary of Rentschler and is now known as Dr. Rentschler Biotechnologie GmbH). The investigation into, and the subsequent response to, the infection can be divided into three stages: Stage I, Investigation and initial response; Stage II, Secondary response; and Stage III: Continuing response.

  12. CD147 overexpression promotes tumorigenicity in Chinese hamster ovary cells.

    Science.gov (United States)

    Yong, Yu-Le; Liao, Cheng-Gong; Wei, Ding; Chen, Zhi-Nan; Bian, Huijie

    2016-04-01

    CD147 overexpresses in many epithelium-originated tumors and plays an important role in tumor migration and invasion. Most studies aim at the role of CD147 in tumor progression using tumor cell models. However, the influence of abnormal overexpression of CD147 on neoplastic transformation of normal cells is unknown. Here, the role of CD147 in malignant phenotype transformation in CHO cells was investigated. Three CHO cell lines that stably overexpressed CD147 (CHO-CD147), EGFP-CD147 (CHO-EGFP-CD147), and EGFP (CHO-EGFP) were generated by transfection of plasmids containing human CD147, EGFP-human CD147, and EGFP genes into CHO cells. Cell migration and invasion were detected by wound healing and transwell matrix penetration assay. Trypan blue exclusion, MTT, cell cycle analysis, and BrdU cell proliferation assay were used to detect cell viability and cell proliferation. Annexin V-FITC analysis was performed to detect apoptosis. We found that CD147 overexpression promoted the migration and invasion of CHO cells. CD147 accelerated the G1 to S phase transition and enhanced the CHO cell proliferation. Overexpression of CD147 inhibited both early- and late-stages of apoptosis of CHO-CD147 cells, which is caused by serum deprivation. CHO-EGFP-CD147 cells showed an increased anchorage-independent growth compared with CHO-EGFP cells as detected by soft-agar colony formation assay. The tumors formed by CHO-CD147 cells in nude mice were larger and coupled with higher expression of proliferating cell nuclear antigen and Ki-67 than that of CHO cells. In conclusion, human CD147 overexpression induces malignant phenotype in CHO cells.

  13. Daidzin and daidzein suppress free-choice ethanol intake by Syrian golden hamsters.

    Science.gov (United States)

    Keung, W M; Vallee, B L

    1993-11-01

    Syrian Golden hamsters prefer and consume large and remarkably constant amounts of ethanol in a simple two-bottle free-choice regimen. Ethanol intake is significantly suppressed by zimelidine, bromocriptine, buspirone, and lithium carbonate, pharmacological agents that have been shown to be beneficial in controlling ethanol intake in alcohol-dependent humans. These results suggest that this ethanol-drinking animal model has high "predictive validity" and can be used effectively in the search for and identification of new agents for the treatment of alcohol abuse. The model has enabled us to confirm the putative antidipsotropic effect of Radix puerariae (RP), an herb long used in traditional Chinese medicine for the treatment of patients who abuse alcohol. A crude extract of RP at a dose of 1.5 g.kg-1 x day-1 significantly suppresses (> 50%) the free-choice ethanol intake of Golden hamsters. Moreover, two major constituents of RP, daidzein (4',7-dihydroxyisoflavone) and daidzin (the 7-glucoside of daidzein), were also shown to suppress free-choice ethanol intake. Daidzin and daidzein, at doses of 150 and 230 mg.kg-1 x day-1, respectively, suppress ethanol intake by > 50%. RP, daidzein, and daidzin treatment do not significantly affect the body weight and water or food intake of the hamsters. These findings identify a class of compounds that offer promise as safe and effective therapeutic agents for alcohol abuse.

  14. Bystander Host Cell Killing Effects of Clostridium perfringens Enterotoxin

    Directory of Open Access Journals (Sweden)

    Archana Shrestha

    2016-12-01

    Full Text Available Clostridium perfringens enterotoxin (CPE binds to claudin receptors, e.g., claudin-4, and then forms a pore that triggers cell death. Pure cultures of host cells that do not express claudin receptors, e.g., fibroblasts, are unaffected by pathophysiologically relevant CPE concentrations in vitro. However, both CPE-insensitive and CPE-sensitive host cells are present in vivo. Therefore, this study tested whether CPE treatment might affect fibroblasts when cocultured with CPE-sensitive claudin-4 fibroblast transfectants or Caco-2 cells. Under these conditions, immunofluorescence microscopy detected increased death of fibroblasts. This cytotoxic effect involved release of a toxic factor from the dying CPE-sensitive cells, since it could be reproduced using culture supernatants from CPE-treated sensitive cells. Supernatants from CPE-treated sensitive cells, particularly Caco-2 cells, were found to contain high levels of membrane vesicles, often containing a CPE species. However, most cytotoxic activity remained in those supernatants even after membrane vesicle depletion, and CPE was not detected in fibroblasts treated with supernatants from CPE-treated sensitive cells. Instead, characterization studies suggest that a major cytotoxic factor present in supernatants from CPE-treated sensitive cells may be a 10- to 30-kDa host serine protease or require the action of that host serine protease. Induction of caspase-3-mediated apoptosis was found to be important for triggering release of the cytotoxic factor(s from CPE-treated sensitive host cells. Furthermore, the cytotoxic factor(s in these supernatants was shown to induce a caspase-3-mediated killing of fibroblasts. This bystander killing effect due to release of cytotoxic factors from CPE-treated sensitive cells could contribute to CPE-mediated disease.

  15. The different radiation response and radiation-induced bystander effects in colorectal carcinoma cells differing in p53 status

    Energy Technology Data Exchange (ETDEWEB)

    Widel, Maria, E-mail: maria.widel@polsl.pl [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland); Lalik, Anna; Krzywon, Aleksandra [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland); Poleszczuk, Jan [College of Inter-faculty Individual Studies in Mathematics and Natural Sciences, University of Warsaw, 93 Zwirki i Wigury Street, 02-089 Warsaw (Poland); Department of Integrated Mathematical Oncology, H. Lee Moffitt Cancer Center & Research Institute, Tampa, Florida (United States); Fujarewicz, Krzysztof; Rzeszowska-Wolny, Joanna [Biosystems Group, Institute of Automatic Control, Silesian University of Technology, 16 Akademicka Street, 44-100 Gliwice (Poland)

    2015-08-15

    Highlights: • We tested radiation response and bystander effect on HCT116p53+/+ and p53−/− cells. • The p53+/+ cells developed premature senescence in exposed and bystander neighbors. • Directly exposed and bystander p53−/− cells died profoundly through apoptosis. • Interleukins 6 and 8 were differently generated by both cell lines. • NFκB path was activated mainly in p53+/+ hit cells, in p53 −/− in bystanders only. - Abstract: Radiation-induced bystander effect, appearing as different biological changes in cells that are not directly exposed to ionizing radiation but are under the influence of molecular signals secreted by irradiated neighbors, have recently attracted considerable interest due to their possible implication for radiotherapy. However, various cells present diverse radiosensitivity and bystander responses that depend, inter alia, on genetic status including TP53, the gene controlling the cell cycle, DNA repair and apoptosis. Here we compared the ionizing radiation and bystander responses of human colorectal carcinoma HCT116 cells with wild type or knockout TP53 using a transwell co-culture system. The viability of exposed to X-rays (0–8 Gy) and bystander cells of both lines showed a roughly comparable decline with increasing dose. The frequency of micronuclei was also comparable at lower doses but at higher increased considerably, especially in bystander TP53-/- cells. Moreover, the TP53-/- cells showed a significantly elevated frequency of apoptosis, while TP53+/+ counterparts expressed high level of senescence. The cross-matched experiments where irradiated cells of one line were co-cultured with non-irradiated cells of opposite line show that both cell lines were also able to induce bystander effects in their counterparts, however different endpoints revealed with different strength. Potential mediators of bystander effects, IL-6 and IL-8, were also generated differently in both lines. The knockout cells secreted IL-6 at

  16. Armenian hamster female protein (serum amyloid P component). Comparison with the sex-regulated homolog in Syrian hamster.

    Science.gov (United States)

    Dowton, S B; Waggoner, D J

    1989-12-01

    Complementary DNA clones for Armenian hamster female protein (FP) were isolated and the complete nucleotide sequence and derived amino acid sequence were determined and compared with relevant data for the closely related Syrian hamster. Although biosynthesis of preSAP is directed by a 1.0-kb mRNA in both genera and the molecular mass of the primary translation product of FP is identical, the FP gene structure and regulation of expression of FP are different in Syrian and Armenian hamsters. Whereas the direction of alteration in FP mRNA levels is divergent in Syrian hamsters during an acute phase reaction, hepatic FP mRNA levels increase in both male and female Armenian hamsters during inflammation. Regulation of expression of Armenian and Syrian hamster FP genes occurs at a pretranslational level.

  17. Molecular and immunological characterization of the first allergenic lipocalin in hamster: the major allergen from Siberian hamster (Phodopus sungorus).

    Science.gov (United States)

    Torres, José Alberto; de Las Heras, Manuel; Maroto, Aroa Sanz; Vivanco, Fernando; Sastre, Joaquín; Pastor-Vargas, Carlos

    2014-08-22

    The most frequent pet allergy is to cat and dog, but in recent years, it has become increasingly popular to have other pets, and the risk of exposure to new allergens is more prevalent. The list of new pets includes hamsters, and one of the most popular hamsters is the Siberian hamster (Phodopus sungorus). The aim of this study was the characterization and cloning of the major allergen from this hamster. The study of its allergenicity and cross-reactivity could improve the specific diagnosis and treatment for hamster-allergic patients. Thirteen Siberian hamster-allergic patients were recruited at the outpatient clinic. Protein extracts were prepared from the hair, urine, and salivary glands of four hamster species (European, golden, Siberian, and Roborovski). IgE-binding proteins were detected by immunoblotting and identified by mass spectrometry. The recombinant protein was produced in Escherichia coli and then purified by metal chelate affinity chromatography. The allergenic properties of the recombinant protein were tested by ELISA and immunoblotting, and biological activity was tested according to capacity for basophil activation. Three IgE-binding proteins were identified in extracts obtained from Siberian hamster hair, urine, and salivary glands. All proteins corresponded to the same protein, which was identified as a lipocalin. This lipocalin had no cross-reactivity with common and golden hamsters. The recombinant allergen was cloned and purified, showing similar IgE reactivity in vitro to Siberian hamster protein extracts. Also, the recombinant allergen was capable of producing biological activation in vivo. The major Siberian hamster allergen was cloned, and allergenic properties were characterized, providing a new tool for specific diagnosis of allergy to Siberian hamster.

  18. Association of bystander cardiopulmonary resuscitation and survival according to ambulance response-times after out-of-hospital cardiac arrest

    DEFF Research Database (Denmark)

    Rajan, Shahzleen; Wissenberg, Mads; Folke, Fredrik;

    2016-01-01

    chances decreased both for patients with bystander CPR and those without. However, the contrast between the survival chances of patients with vs. without bystander CPR increased over time: within 5 minutes, 30-day survival was 14.5% (95% CI: 12.8-16.4) vs. 6.3% (95% CI: 5.1-7.6), corresponding to 2.......3 times higher chances of survival associated with bystander CPR; within 10 minutes, 30-day survival chances were 6.7% (95% CI: 5.4-8.1) vs. 2.2% (95% CI: 1.5-3.1), corresponding to 3.0 times higher chances of 30-day survival associated with bystander CPR. The contrast in 30-day survival became...... statistically insignificant when response time exceeded 13 minutes (bystander CPR vs. no bystander CPR: 3.7% [95% CI: 2.2-5.4] vs. 1.5% [95% CI: 0.6-2.7]) but 30-day survival was still 2.5 times higher associated with bystander CPR. Based on the model and Danish OHCA Statistics, an additional of 233 patients...

  19. Raising a Red Flag on Dating Violence: Evaluation of a Low-Resource, College-Based Bystander Behavior Intervention Program.

    Science.gov (United States)

    Borsky, Amanda E; McDonnell, Karen; Turner, Monique Mitchell; Rimal, Rajiv

    2016-03-09

    Encouraging bystanders to intervene safely and effectively in situations that could escalate to violence-known as bystander behavior programs-is a growing yet largely untested strategy to prevent dating violence. Using a quasi-experimental design, we evaluate a low-resource, low-intensity intervention aimed at preventing dating violence among college students. The integrated behavioral model (IBM) was used to guide the evaluation. We also assess which IBM variables were most strongly associated with bystander behaviors. Participants were drawn from two Virginia colleges that predominantly train females in the health profession sciences. The intervention group (n = 329) participated in a university-wide bystander behavior intervention consisting of a 30-min presentation on dating violence at new-student orientation and a week-long "red flag" social marketing campaign on campus to raise awareness of dating violence. Controlling for changes at the comparison university, results showed an increase in bystander behaviors, such as encouraging a friend who may be in an abusive relationship to get help, after the intervention and adjusting for potential confounders (increase of 1.41 bystander behaviors, p = .04). However, no significant changes were found for bystander intentions, self-efficacy, social norms, or attitudes related to dating violence from pre- to post-intervention. Self-efficacy had a direct relationship with bystander behaviors. Results suggest that low-resource interventions have a modest effect on increasing bystander behaviors. However, higher resource interventions likely are needed for a larger impact, especially among students who already demonstrate strong baseline intentions to intervene and prevent dating violence.

  20. Development of a mathematical model to study the radiation-induced bystander effect

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2011-07-01

    Living organisms are composed of millions of cells that together perform tasks of great complexity. Although every cell has an internal structure that obeys the laws of chemistry and biochemistry, it is the interactions between cells that generate a range of different phenomena. Until the 1990s it was believed that the DNA was the single molecule affected by radiation, the so-called theory of the single target. But some observations began to challenge this theory; in 1992 the bystander effect was described by Nagasawa and Little. This effect is responsible for a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. Understanding the bystander effect may have important consequences for therapy and studies of low-dose risk. In this work, we have developed a computational model to study the bystander effect. This computational model is a two-dimensional cellular automata, consisting of two overlapping networks, where the first represents the cell culture, and the second one, the medium in which cells are embedded. The computational model allows the establishment of curves to describe the behavior of the effect for different levels of signals released in the irradiated medium by the irradiated cells or by the bystander cells when a second order effect is considered. The percentage of cell survival obtained from the mathematical model showed to be in good agreement with experimental data available in the literature. (author)

  1. Vulnerable Children in Varying Classroom Contexts Bystanders' Behaviors Moderate the Effects of Risk Factors on Victimization

    NARCIS (Netherlands)

    Kärnä, A.; Voeten, M.J.M.; Poskiparta, E.H.; Salmivalli, C.

    2010-01-01

    We examined whether the bystanders' behaviors in bullying situations influence vulnerable students' risk for victimization. The sample consisted of 6,980 primary school children from Grades 3-5, who were nested within 378 classrooms in 77 schools. These students filled out Internet-based questionnai

  2. Vulnerable Children in Varying Classroom Contexts: Bystanders' Behaviors Moderate the Effects of Risk Factors on Victimization

    Science.gov (United States)

    Karna, Antti; Voeten, Marinus; Poskiparta, Elisa; Salmivalli, Christina

    2010-01-01

    We examined whether the bystanders' behaviors in bullying situations influence vulnerable students' risk for victimization. The sample consisted of 6,980 primary school children from Grades 3-5, who were nested within 378 classrooms in 77 schools. These students filled out Internet-based questionnaires in their schools' computer labs. The results…

  3. Bystander Intervention, Bullying, and Victimization: A Multilevel Analysis of New Zealand High Schools

    Science.gov (United States)

    Denny, Simon; Peterson, Elizabeth R.; Stuart, Jaimee; Utter, Jennifer; Bullen, Pat; Fleming, Theresa; Ameratunga, Shanthi; Clark, Terryann; Milfont, Taciano

    2015-01-01

    This study examines the association between schools and student bullying behaviors and victimization among a nationally representative sample (N = 9,107) of New Zealand high school students. In particular, the study sought to explore the role of characteristics of schools and school culture with respect to bystander behavior, while controlling for…

  4. BYSTANDERS, ADAPTIVE RESPONSES AND GENOMIC INSTABILITY - POTENTIAL MODIFIERS OF LOW-DOSE CANCER RESPONSES.

    Science.gov (United States)

    Bystanders, Adaptive Responses and Genomic Instability -Potential Modifiers ofLow-DoseCancer Responses.There has been a concerted effort in the field of radiation biology to better understand cellularresponses that could have an impact on the estin1ation of cancer...

  5. Tell the Teacher or Tell the Bully Off: Children's Strategy Production for Bystanders to Bullying

    Science.gov (United States)

    Rock, Patrick F.; Baird, Jodie A.

    2012-01-01

    Although children's reticence to intervene as bystanders to bullying is well established, the reasons for their inaction remain unclear. One possibility is that they are incapable of generating appropriate response strategies in these situations. This study examined the number and type of strategies children (N = 104, 6-11 years) could generate…

  6. R.U. Ready?: Peer Education and Bystander Intervention Sexual Assault Programming

    Science.gov (United States)

    Schweer, Jen Luettel; Heather, Katie; Kay, Kathryn; Stewart, K. Leigh; Kovach, Laura

    2012-01-01

    R.U. Ready? at Georgetown University is an annual sexual assault awareness event that incorporates peer education and resources with opportunities for students, staff, and faculty to dialogue about providing bystander intervention throughout the campus community. Beyond dialogue, participants learn about student activism and the resources and…

  7. Acting in solidarity : Testing an extended dual pathway model of collective action by bystander group members

    NARCIS (Netherlands)

    Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee

    2015-01-01

    We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach, 2004)

  8. A Bystander Bullying Psychoeducation Program with Middle School Students: A Preliminary Report

    Science.gov (United States)

    Midgett, Aida; Doumas, Diana; Sears, Dara; Lundquist, Amanda; Hausheer, Robin

    2015-01-01

    This study evaluated the effectiveness of a brief, stand-alone bystander bullying psychoeducation program for middle school students. The purpose of the program was to train students to take action as peer advocates. Pre- and post-tests indicated that after completing the 90-minute psychoeducation program, students reported an increase in their…

  9. A Meta-Analysis of School-Based Bullying Prevention Programs' Effects on Bystander Intervention Behavior

    Science.gov (United States)

    Polanin, Joshua R.; Espelage, Dorothy L.; Pigott, Therese D.

    2012-01-01

    This meta-analysis synthesized bullying prevention programs' effectiveness at increasing bystander intervention in bullying situations. Evidence from 12 school-based programs, involving 12,874 students, indicated that overall the programs were successful (Hedges's g = 0.20, 95% confidence interval [CI] = 0.11 to 0.29, p = 0.001), with larger…

  10. The role of bystanders during rescue and resuscitation of drowning victims

    NARCIS (Netherlands)

    Venema, Allart M.; Groothoff, Johan W.; Bierens, Joost J. L. M.

    2010-01-01

    Background: Bystanders make a critical difference in the survival of drowning victims. Little information on their role before arrival of the Emergency Medical Services (EMS) is available in the scientific literature. In a descriptive study, this role is investigated. Methods and results: We studied

  11. Reducing Sexual Violence on Campus: The Role of Student Leaders as Empowered Bystanders

    Science.gov (United States)

    Banyard, Victoria L.; Moynihan, Mary M.; Crossman, Maria T.

    2009-01-01

    Sexual violence is a widespread problem for college communities. Students, faculty, and staff are increasingly involved in prevention efforts. To date, however, evaluation of sexual violence prevention programs has shown mixed results. One promising new practice teaches segments of college communities to be engaged, positive bystanders. It aims to…

  12. Using Role-Taking and Behavioral Mimicking in Games to Increase Awareness on the Bystander Effect

    DEFF Research Database (Denmark)

    Soegaard Andersen, Josephine; Schoenau-Fog, Henrik

    2015-01-01

    with behavioral mimicking. The game concept should include a relatable (preferably player modifiable) avatar, so the player can relate and adhere to the empathy and intent to help. Since the bystander effect takes place in groups where deindividuation also is common, this should require a behavioral change...

  13. Using a Multimedia Social Marketing Campaign to Increase Active Bystanders on the College Campus

    Science.gov (United States)

    Potter, Sharyn J.

    2012-01-01

    Objective: To evaluate the campus-wide administration of the Know Your Power bystander-oriented social marketing campaign. Participants: Undergraduate students at a public college were invited to participate in a public awareness survey before and after the 6-week campaign administration in February and March 2009. Methods: Pretest and posttests…

  14. Bystander Behavior in Bullying Situations: Basic Moral Sensitivity, Moral Disengagement and Defender Self-Efficacy

    Science.gov (United States)

    Thornberg, Robert; Jungert, Tomas

    2013-01-01

    The aim of the present study was to investigate how basic moral sensitivity in bullying, moral disengagement in bullying and defender self-efficacy were related to different bystander behaviors in bullying. Therefore, we examined pathways that linked students' basic moral sensitivity, moral disengagement, and defender self-efficacy to different…

  15. Neutron exposures in human cells: bystander effect and relative biological effectiveness.

    Directory of Open Access Journals (Sweden)

    Isheeta Seth

    Full Text Available Bystander effects have been observed repeatedly in mammalian cells following photon and alpha particle irradiation. However, few studies have been performed to investigate bystander effects arising from neutron irradiation. Here we asked whether neutrons also induce a bystander effect in two normal human lymphoblastoid cell lines. These cells were exposed to fast neutrons produced by targeting a near-monoenergetic 50.5 MeV proton beam at a Be target (17 MeV average neutron energy, and irradiated-cell conditioned media (ICCM was transferred to unirradiated cells. The cytokinesis-block micronucleus assay was used to quantify genetic damage in radiation-naïve cells exposed to ICCM from cultures that received 0 (control, 0.5, 1, 1.5, 2, 3 or 4 Gy neutrons. Cells grown in ICCM from irradiated cells showed no significant increase in the frequencies of micronuclei or nucleoplasmic bridges compared to cells grown in ICCM from sham irradiated cells for either cell line. However, the neutron beam has a photon dose-contamination of 5%, which may modulate a neutron-induced bystander effect. To determine whether these low doses of contaminating photons can induce a bystander effect, cells were irradiated with cobalt-60 at doses equivalent to the percent contamination for each neutron dose. No significant increase in the frequencies of micronuclei or bridges was observed at these doses of photons for either cell line when cultured in ICCM. As expected, high doses of photons induced a clear bystander effect in both cell lines for micronuclei and bridges (p<0.0001. These data indicate that neutrons do not induce a bystander effect in these cells. Finally, neutrons had a relative biological effectiveness of 2.0 ± 0.13 for micronuclei and 5.8 ± 2.9 for bridges compared to cobalt-60. These results may be relevant to radiation therapy with fast neutrons and for regulatory agencies setting standards for neutron radiation protection and safety.

  16. Bystander Motivation in Bullying Incidents: To Intervene or Not to Intervene?

    Directory of Open Access Journals (Sweden)

    Robert Thornberg

    2012-08-01

    Full Text Available Introduction: This research sought to extend knowledge about bystanders in bullying situations with a focus on the motivations that lead them to different responses. The 2 primary goals of this study were to investigate the reasons for children’s decisions to help or not to help a victim when witnessing bullying, and to generate a grounded theory (or conceptual framework of bystander motivation in bullying situations.Methods: Thirty students ranging in age from 9 to 15 years (M=11.9; SD=1.7 from an elementary and middle school in the southeastern United States participated in this study. Open- ended, semistructured interviews were used, and sessions ranged from 30 to 45 minutes. We conducted qualitative methodology and analyses to gain an in-depth understanding of children’s perspectives and concerns when witnessing bullying.Results: A key finding was a conceptual framework of bystander motivation to intervene in bullying situations suggesting that deciding whether to help or not help the victim in a bullying situation depends on how bystanders define and evaluate the situation, the social context, and their own agency. Qualitative analysis revealed 5 themes related to bystander motives and included: interpretation of harm in the bullying situation, emotional reactions, social evaluating, moral evaluating, and intervention self-efficacy.Conclusion: Given the themes that emerged surrounding bystanders’ motives to intervene or abstain from intervening, respondents reported 3 key elements that need to be confirmed in future research and that may have implications for future work on bullying prevention. These included: first, the potential importance of clear communication to children that adults expect bystanders to intervene when witnessing bullying; second, the potential of direct education about how bystanders can interveneto increase children’s self-efficacy as defenders of those who are victims of bullying; and third, the assumption

  17. The Role of DNA Methylation Changes in Radiation-Induced Bystander Effects in cranial irradiated Mice

    Science.gov (United States)

    Zhang, Meng; Sun, Yeqing; Xue, Bei; Wang, Xinwen; Wang, Jiawen

    2016-07-01

    Heavy-ion radiation could lead to bystander effect in neighboring non-hit cells by signals released from directly-irradiated cells. The exact mechanisms of radiation-induced bystander effect in distant organ remain obscure, yet accumulating evidence points to the role of DNA methylation changes in bystander effect. To identify the molecular mechanism that underlies bystander effects of heavy-ion radiation, the male Balb/c and C57BL mice were cranial exposed to 40, 200, 2000mGy dose of carbon heavy-ion radiation, while the rest of the animal body was shielded. The γH2AX foci as the DNA damage biomarker in directly irradiation organ ear and the distant organ liver were detected on 0, 1, 2, 6, 12 and 24h after radiation, respectively. Methylation-sensitive amplifcation polymorphism (MSAP) was used to monitor the level of polymorphic genomic DNA methylation changed with dose and time effects. The results show that cranial irradiated mice could induce the γH2AX foci and genomic DNA methylation changes significantly in both the directly irradiation organ ear and the distant organ liver. The percent of DNA methylation changes were time-dependent and tissue-specific. Demethylation polymorphism rate were highest separately at 1 h in 200 mGy and 6 h in 2000 mGy after irradiation in ear. The global DNA methylation changes tended to occur in the CG sites. We also found that the numbers of γH2AX foci and the genomic methylation changes of heavy-ion radiation-induced bystander effect in liver could be obvious 1 h after radiation and achieved the maximum at 6 h, while the changes could recover gradually at 12 h. The results suggest that mice head exposed to heavy-ion radiation can induce damage and methylation pattern changed in both directly radiation organ ear and distant organ liver. Moreover, our findings are important to understand the molecular mechanism of radiation induced bystander effects in vivo. Keywords: Heavy-ion radiation; Bystander effect; DNA methylation; γH2

  18. Infection-induced bystander-apoptosis of monocytes is TNF-alpha-mediated.

    Directory of Open Access Journals (Sweden)

    Stephan Dreschers

    Full Text Available Phagocytosis induced cell death (PICD is crucial for controlling phagocyte effector cells, such as monocytes, at sites of infection, and essentially contributes to termination of inflammation. Here we tested the hypothesis, that during PICD bystander apoptosis of non-phagocyting monocytes occurs, that apoptosis induction is mediated via tumor necrosis factor-alpha (TNF-α and that TNF-α secretion and -signalling is causal. Monocytes were infected with Escherichia coli (E. coli, expressing green fluorescent protein (GFP, or a pH-sensitive Eos-fluorescent protein (EOS-FP. Monocyte phenotype, phagocytic activity, apoptosis, TNF-receptor (TNFR-1, -2-expression and TNF-α production were analyzed. Apoptosis occured in phagocyting and non-phagocyting, bystander monocytes. Bacterial transport to the phagolysosome was no prerequisite for apoptosis induction, and desensitized monocytes from PICD, as confirmed by EOS-FP expressing E. coli. Co-cultivation with non-infected carboxyfluorescein-succinimidyl-ester- (CFSE- labelled monocytes resulted in significant apoptotic cell death of non-infected bystander monocytes. This process required protein de-novo synthesis and still occurred in a diminished way in the absence of cell-cell contact. E. coli induced a robust TNF-α production, leading to TNF-mediated apoptosis in monocytes. Neutralization with an anti-TNF-α antibody reduced monocyte bystander apoptosis significantly. In contrast to TNFR2, the pro-apoptotic TNFR1 was down-regulated on the monocyte surface, internalized 30 min. p.i. and led to apoptosis predominantly in monocytes without phagocyting bacteria by themselves. Our results suggest, that apoptosis of bystander monocytes occurs after infection with E. coli via internalization of TNFR1, and indicate a relevant role for TNF-α. Modifying monocyte apoptosis in sepsis may be a future therapeutic option.

  19. Bystander responses in low dose irradiated cells treated with plasma from gamma irradiated blood

    Energy Technology Data Exchange (ETDEWEB)

    Acheva, A; Georgieva, R; Rupova, I; Boteva, R [Laboratory Molecular Radiobiology and Epidemiology, National Centre of Radiobiology and Radiation Protection, 132 Kliment Ohridski blvd, Sofia 1756 (Bulgaria); Lyng, F [Radiation and Environmental Science Center, Dublin Institute of Technology, Kevin st, Dublin 8 (Ireland)], E-mail: anjin_a@mail.bg

    2008-02-01

    There are two specific low-dose radiation-induced responses that have been the focus of radiobiologists' interest in recent years. These are the bystander effect in non-irradiated cells and the adaptive response to a challenge dose after prior low dose irradiation. In the present study we have investigated if plasma from irradiated blood can act as a 'challenge dose' on low dose irradiated reporter epithelial cells (HaCaT cell line). The main aim was to evaluate the overall effect of low dose irradiation (0.05 Gy) of reporter cells and the influence of bystander factors in plasma from 0.5 Gy gamma irradiated blood on these cells. The effects were estimated by clonogenic survival of the reporter cells. We also investigated the involvement of reactive oxygen species (ROS) as potential factors involved in the bystander signaling. Calcium fluxes and mitochondrial membrane potential (MMP) depolarization were also examined as a marker for initiation of apoptosis in the reporter cells. The results show that there are large individual differences in the production of bystander effects and adaptive responses between different donors. These may be due to the specific composition of the donor plasma. The observed effects generally could be divided into two groups: adaptive responses and additive effects. ROS appeared to be involved in the responses of the low dose pretreated reporter cells. In all cases there was a significant decrease in MMP which may be an early event in the apoptotic process. Calcium signaling also appeared to be involved in triggering apoptosis in the low dose pretreated reporter cells. The heterogeneity of the bystander responses makes them difficult to be modulated for medical uses. Specific plasma characteristics that cause these large differences in the responses would need to be identified to make them useful for radiotherapy.

  20. Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-17

    It is now accepted that biological effects may occur in cells that were not themselves traversed by ionizing radiation but are close to those that were. Little is known about the mechanism underlying such a bystander effect, although cell-to-cell communication is thought to be important. Previous work demonstrated a significant bystander effect for clonogenic survival and oncogenic transformation in C3H 10T(1/2) cells. Additional studies were undertaken to assess the importance of the degree of cell-to-cell contact at the time of irradiation on the magnitude of this bystander effect by varying the cell density. When 10% of cells were exposed to a range of 2-12 alpha particles, a significantly greater number of cells were inactivated when cells were irradiated at high density than at low density. In addition, the oncogenic transformation frequency was significantly higher in high-density cultures. These results suggest that when a cell is hit by radiation, the transmission of the bystander signal through cell-to-cell contact is an important mediator of the effect, implicating the involvement of intracellular communication through gap junctions. Additional studies to address the relationship between the bystander effect and the adaptive response were undertaken. A novel apparatus, where targeted and non-targeted cells were grown in close proximity, was used to investigate these. It was further examined whether a bystander effect or an adaptive response could be induced by a factor(s) present in the supernatants of cells exposed to a high or low dose of X-rays, respectively. When non-hit cells were co-cultured for 24 h with cells irradiated with 5 Gy alpha-particles, a significant increase in both cell killing and oncogenic transformation frequency was observed. If these cells were treated with 2 cGy X-rays 5 h before co-culture with irradiated cells, approximately 95% of the bystander effect was cancelled out. A 2.5-fold decrease in the oncogenic transformation

  1. Studies of Bystander Effects in 3-D Tissue Systems Using a Low-LET Microbeam

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-17

    It is now accepted that biological effects may occur in cells that were not themselves traversed by ionizing radiation but are close to those that were. Little is known about the mechanism underlying such a bystander effect, although cell-to-cell communication is thought to be important. Previous work demonstrated a significant bystander effect for clonogenic survival and oncogenic transformation in C3H 10T(1/2) cells. Additional studies were undertaken to assess the importance of the degree of cell-to-cell contact at the time of irradiation on the magnitude of this bystander effect by varying the cell density. When 10% of cells were exposed to a range of 2-12 alpha particles, a significantly greater number of cells were inactivated when cells were irradiated at high density than at low density. In addition, the oncogenic transformation frequency was significantly higher in high-density cultures. These results suggest that when a cell is hit by radiation, the transmission of the bystander signal through cell-to-cell contact is an important mediator of the effect, implicating the involvement of intracellular communication through gap junctions. Additional studies to address the relationship between the bystander effect and the adaptive response were undertaken. A novel apparatus, where targeted and non-targeted cells were grown in close proximity, was used to investigate these. It was further examined whether a bystander effect or an adaptive response could be induced by a factor(s) present in the supernatants of cells exposed to a high or low dose of X-rays, respectively. When non-hit cells were co-cultured for 24 h with cells irradiated with 5 Gy alpha-particles, a significant increase in both cell killing and oncogenic transformation frequency was observed. If these cells were treated with 2 cGy X-rays 5 h before co-culture with irradiated cells, approximately 95% of the bystander effect was cancelled out. A 2.5-fold decrease in the oncogenic transformation

  2. Thermostability of sperm nuclei assessed by microinjection into hamster oocytes

    Science.gov (United States)

    Nuclei isolated from spermatozoa of various species (golden hamster, mouse, human, rooster, and the fish tilapia) were heated at 60 degrees-125 degrees C for 20-120 min and then microinjected into hamster oocytes to determine whether they could decondense and develop into pronucl...

  3. Characteristics of 263K scrapie agent in multiple hamster species.

    Science.gov (United States)

    Meade-White, Kimberly D; Barbian, Kent D; Race, Brent; Favara, Cynthia; Gardner, Don; Taubner, Lara; Porcella, Stephen; Race, Richard

    2009-02-01

    Transmissible spongiform encephalopathy (TSE) diseases are known to cross species barriers, but the pathologic and biochemical changes that occur during transmission are not well understood. To better understand these changes, we infected 6 hamster species with 263K hamster scrapie strain and, after each of 3 successive passages in the new species, analyzed abnormal proteinase K (PK)-resistant prion protein (PrPres) glycoform ratios, PrPres PK sensitivity, incubation periods, and lesion profiles. Unique 263K molecular and biochemical profiles evolved in each of the infected hamster species. Characteristics of 263K in the new hamster species seemed to correlate best with host factors rather than agent strain. Furthermore, 2 polymorphic regions of the prion protein amino acid sequence correlated with profile differences in these TSE-infected hamster species.

  4. Circadian rhythms of photorefractory siberian hamsters remain responsive to melatonin.

    Science.gov (United States)

    Butler, Matthew P; Paul, Matthew J; Turner, Kevin W; Park, Jin Ho; Driscoll, Joseph R; Kriegsfeld, Lance J; Zucker, Irving

    2008-04-01

    Short day lengths increase the duration of nocturnal melatonin (Mel) secretion, which induces the winter phenotype in Siberian hamsters. After several months of continued exposure to short days, hamsters spontaneously revert to the spring-summer phenotype. This transition has been attributed to the development of refractoriness of Mel-binding tissues, including the suprachiasmatic nucleus (SCN), to long-duration Mel signals. The SCN of Siberian hamsters is required for the seasonal response to winter-like Mel signals, and becomes refractory to previously effective long-duration Mel signals restricted to this area. Acute Mel treatment phase shifts circadian locomotor rhythms of photosensitive Siberian hamsters, presumably by affecting circadian oscillators in the SCN. We tested whether seasonal refractoriness of the SCN to long-duration Mel signals also renders the circadian system of Siberian hamsters unresponsive to Mel. Males manifesting free-running circadian rhythms in constant dim red light were injected with Mel or vehicle for 5 days on a 23.5-h T-cycle beginning at circadian time 10. Mel injections caused significantly larger phase advances in activity onset than did the saline vehicle, but the magnitude of phase shifts to Mel did not differ between photorefractory and photosensitive hamsters. Similarly, when entrained to a 16-h light/8-h dark photocycle, photorefractory and photosensitive hamsters did not differ in their response to Mel injected 4 h before the onset of the dark phase. Activity onset in Mel-injected hamsters was masked by light but was revealed to be significantly earlier than in vehicle-injected hamsters upon transfer to constant dim red light. The acute effects of melatonin on circadian behavioral rhythms are preserved in photorefractory hamsters.

  5. Radiation and chemotherapy bystander effects induce early genomic instability events: telomere shortening and bridge formation coupled with mitochondrial dysfunction.

    LENUS (Irish Health Repository)

    Gorman, Sheeona

    2012-02-01

    The bridge breakage fusion cycle is a chromosomal instability mechanism responsible for genomic changes. Radiation bystander effects induce genomic instability; however, the mechanism driving this instability is unknown. We examined if radiation and chemotherapy bystander effects induce early genomic instability events such as telomere shortening and bridge formation using a human colon cancer explant model. We assessed telomere lengths, bridge formations, mitochondrial membrane potential and levels of reactive oxygen species in bystander cells exposed to medium from irradiated and chemotherapy-treated explant tissues. Bystander cells exposed to media from 2Gy, 5Gy, FOLFOX treated tumor and matching normal tissue showed a significant reduction in telomere lengths (all p values <0.018) and an increase in bridge formations (all p values <0.017) compared to bystander cells treated with media from unirradiated tissue (0Gy) at 24h. There was no significant difference between 2Gy and 5Gy treatments, or between effects elicited by tumor versus matched normal tissue. Bystander cells exposed to media from 2Gy irradiated tumor tissue showed significant depolarisation of the mitochondrial membrane potential (p=0.012) and an increase in reactive oxygen species levels. We also used bystander cells overexpressing a mitochondrial antioxidant manganese superoxide dismutase (MnSOD) to examine if this antioxidant could rescue the mitochondrial changes and subsequently influence nuclear instability events. In MnSOD cells, ROS levels were reduced (p=0.02) and mitochondrial membrane potential increased (p=0.04). These events were coupled with a decrease in percentage of cells with anaphase bridges and a decrease in the number of cells undergoing telomere length shortening (p values 0.01 and 0.028 respectively). We demonstrate that radiation and chemotherapy bystander responses induce early genomic instability coupled with defects in mitochondrial function. Restoring mitochondrial

  6. Critical role of gap junction communication, calcium and nitric oxide signaling in bystander responses to focal photodynamic injury

    OpenAIRE

    Calì, Bianca; Ceolin, Stefano; Ceriani, Federico; Bortolozzi, Mario; Agnellini, Andrielly H.R.; Zorzi, Veronica; Predonzani, Andrea; Bronte, Vincenzo; Molon, Barbara; Mammano, Fabio

    2015-01-01

    Ionizing and nonionizing radiation affect not only directly targeted cells but also surrounding “bystander” cells. The underlying mechanisms and therapeutic role of bystander responses remain incompletely defined. Here we show that photosentizer activation in a single cell triggers apoptosis in bystander cancer cells, which are electrically coupled by gap junction channels and support the propagation of a Ca2+ wave initiated in the irradiated cell. The latter also acts as source of nitric oxi...

  7. Critical role of gap junction communication, calcium and nitric oxide signaling in bystander responses to focal photodynamic injury

    OpenAIRE

    Cali, B.; Ceolin, S.; Ceriani, F.; Bortolozzi, M.; Agnellini, A.H.R.; Zorzi, V.; Predonzani, A.; BRONTE, V; Molon, B.; Mammano, F.

    2015-01-01

    Ionizing and nonionizing radiation affect not only directly targeted cells but also\\ud surrounding “bystander” cells. The underlying mechanisms and therapeutic role of\\ud bystander responses remain incompletely deined. Here we show that photosentizer\\ud activation in a single cell triggers apoptosis in bystander cancer cells, which are\\ud electrically coupled by gap junction channels and support the propagation of a Ca2+\\ud wave initiated in the irradiated cell. The latter also acts as source...

  8. Radiation and chemotherapy bystander effects induce early genomic instability events: Telomere shortening and bridge formation coupled with mitochondrial dysfunction

    Energy Technology Data Exchange (ETDEWEB)

    Gorman, Sheeona; Tosetto, Miriam [Centre for Colorectal Disease, St. Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); Lyng, Fiona; Howe, Orla [Radiation and Environmental Science Centre, Dublin Institute of Technology and St. Luke' s Hospital, Dublin (Ireland); Sheahan, Kieran; O' Donoghue, Diarmuid; Hyland, John; Mulcahy, Hugh [Centre for Colorectal Disease, St. Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland); O' Sullivan, Jacintha, E-mail: jacintha.osullivan@ucd.ie [Centre for Colorectal Disease, St. Vincent' s University Hospital, Elm Park, Dublin 4 (Ireland)

    2009-10-02

    The bridge breakage fusion cycle is a chromosomal instability mechanism responsible for genomic changes. Radiation bystander effects induce genomic instability; however, the mechanism driving this instability is unknown. We examined if radiation and chemotherapy bystander effects induce early genomic instability events such as telomere shortening and bridge formation using a human colon cancer explant model. We assessed telomere lengths, bridge formations, mitochondrial membrane potential and levels of reactive oxygen species in bystander cells exposed to medium from irradiated and chemotherapy-treated explant tissues. Bystander cells exposed to media from 2 Gy, 5 Gy, FOLFOX treated tumor and matching normal tissue showed a significant reduction in telomere lengths (all p values <0.018) and an increase in bridge formations (all p values <0.017) compared to bystander cells treated with media from unirradiated tissue (0 Gy) at 24 h. There was no significant difference between 2 Gy and 5 Gy treatments, or between effects elicited by tumor versus matched normal tissue. Bystander cells exposed to media from 2 Gy irradiated tumor tissue showed significant depolarisation of the mitochondrial membrane potential (p = 0.012) and an increase in reactive oxygen species levels. We also used bystander cells overexpressing a mitochondrial antioxidant manganese superoxide dismutase (MnSOD) to examine if this antioxidant could rescue the mitochondrial changes and subsequently influence nuclear instability events. In MnSOD cells, ROS levels were reduced (p = 0.02) and mitochondrial membrane potential increased (p = 0.04). These events were coupled with a decrease in percentage of cells with anaphase bridges and a decrease in the number of cells undergoing telomere length shortening (p values 0.01 and 0.028 respectively). We demonstrate that radiation and chemotherapy bystander responses induce early genomic instability coupled with defects in mitochondrial function. Restoring

  9. Regions of High Out-Of-Hospital Cardiac Arrest Incidence and Low Bystander CPR Rates in Victoria, Australia

    Science.gov (United States)

    Straney, Lahn D.; Bray, Janet E.; Beck, Ben; Finn, Judith; Bernard, Stephen; Dyson, Kylie; Lijovic, Marijana; Smith, Karen

    2015-01-01

    Background Out-of-hospital cardiac arrest (OHCA) remains a major public health issue and research has shown that large regional variation in outcomes exists. Of the interventions associated with survival, the provision of bystander CPR is one of the most important modifiable factors. The aim of this study is to identify census areas with high incidence of OHCA and low rates of bystander CPR in Victoria, Australia Methods We conducted an observational study using prospectively collected population-based OHCA data from the state of Victoria in Australia. Using ArcGIS (ArcMap 10.0), we linked the location of the arrest using the dispatch coordinates (longitude and latitude) to Victorian Local Government Areas (LGAs). We used Bayesian hierarchical models with random effects on each LGA to provide shrunken estimates of the rates of bystander CPR and the incidence rates. Results Over the study period there were 31,019 adult OHCA attended, of which 21,436 (69.1%) cases were of presumed cardiac etiology. Significant variation in the incidence of OHCA among LGAs was observed. There was a 3 fold difference in the incidence rate between the lowest and highest LGAs, ranging from 38.5 to 115.1 cases per 100,000 person-years. The overall rate of bystander CPR for bystander witnessed OHCAs was 62.4%, with the rate increasing from 56.4% in 2008–2010 to 68.6% in 2010–2013. There was a 25.1% absolute difference in bystander CPR rates between the highest and lowest LGAs. Conclusion Significant regional variation in OHCA incidence and bystander CPR rates exists throughout Victoria. Regions with high incidence and low bystander CPR participation can be identified and would make suitable targets for interventions to improve CPR participation rates. PMID:26447844

  10. Regions of High Out-Of-Hospital Cardiac Arrest Incidence and Low Bystander CPR Rates in Victoria, Australia.

    Directory of Open Access Journals (Sweden)

    Lahn D Straney

    Full Text Available Out-of-hospital cardiac arrest (OHCA remains a major public health issue and research has shown that large regional variation in outcomes exists. Of the interventions associated with survival, the provision of bystander CPR is one of the most important modifiable factors. The aim of this study is to identify census areas with high incidence of OHCA and low rates of bystander CPR in Victoria, Australia.We conducted an observational study using prospectively collected population-based OHCA data from the state of Victoria in Australia. Using ArcGIS (ArcMap 10.0, we linked the location of the arrest using the dispatch coordinates (longitude and latitude to Victorian Local Government Areas (LGAs. We used Bayesian hierarchical models with random effects on each LGA to provide shrunken estimates of the rates of bystander CPR and the incidence rates.Over the study period there were 31,019 adult OHCA attended, of which 21,436 (69.1% cases were of presumed cardiac etiology. Significant variation in the incidence of OHCA among LGAs was observed. There was a 3 fold difference in the incidence rate between the lowest and highest LGAs, ranging from 38.5 to 115.1 cases per 100,000 person-years. The overall rate of bystander CPR for bystander witnessed OHCAs was 62.4%, with the rate increasing from 56.4% in 2008-2010 to 68.6% in 2010-2013. There was a 25.1% absolute difference in bystander CPR rates between the highest and lowest LGAs.Significant regional variation in OHCA incidence and bystander CPR rates exists throughout Victoria. Regions with high incidence and low bystander CPR participation can be identified and would make suitable targets for interventions to improve CPR participation rates.

  11. Radiation-induced bystander effect in healthy G{sub 0} human lymphocytes: Biological and clinical significance

    Energy Technology Data Exchange (ETDEWEB)

    Belloni, Paola; Latini, Paolo [Department of Agrobiology and Agrochemistry, University of Tuscia, Via San Camillo De Lellis, I-01100 Viterbo (Italy); Palitti, Fabrizio, E-mail: palitti@unitus.it [Department of Agrobiology and Agrochemistry, University of Tuscia, Via San Camillo De Lellis, I-01100 Viterbo (Italy)

    2011-08-01

    To study the bystander effects, G{sub 0} human peripheral blood lymphocytes were X-irradiated with 0.1, 0.5 and 3 Gy. After 24 h, cell-free conditioned media from irradiated cultures were transferred to unexposed lymphocytes. Following 48 h of medium transfer, viability, induction of apoptosis, telomere shortening, reactive oxygen species (ROS) levels and micronuclei (after stimulation) were analyzed. A statistically significant decrement in cell viability, concomitant with the loss of mitochondrial membrane potential, telomere shortening, increases in hydrogen peroxide (H{sub 2}O{sub 2}) and superoxide anion (O{sub 2}{sup -}) with depletion of intracellular glutathione (GSH) level, and higher frequencies of micronuclei, were observed in bystander lymphocytes incubated with medium from 0.5 and 3 Gy irradiated samples, compared to lymphocytes unexposed. Furthermore, no statistically significant difference between the response to 0.5 and 3 Gy of irradiation in bystander lymphocytes, was found. However, when lymphocytes were irradiated with 0.1 Gy, no bystander effect with regard to viability, apoptosis, telomere length, and micronuclei was observed, although a high production of ROS level persisted. Radiation in the presence of the radical scavenger dimethyl sulfoxide (DMSO) suppressed oxidative stress induced by 3 Gy of X-rays with the effective elimination of bystander effects, suggesting a correlation between ROS and bystander signal formation in irradiated cells. The data propose that bystander effect might be mostly due to the reactions of radiation induced free radicals on DNA, with the existence of a threshold at which the bystander signal is not operative (0.1 Gy dose of X-rays). Our results may have clinical implications for health risk associated with radiation exposure.

  12. Improved Anticancer Photothermal Therapy Using the Bystander Effect Enhanced by Antiarrhythmic Peptide Conjugated Dopamine-Modified Reduced Graphene Oxide Nanocomposite.

    Science.gov (United States)

    Yu, Jiantao; Lin, Yu-Hsin; Yang, Lingyan; Huang, Chih-Ching; Chen, Liliang; Wang, Wen-Cheng; Chen, Guan-Wen; Yan, Junyan; Sawettanun, Saranta; Lin, Chia-Hua

    2017-01-01

    Despite tremendous efforts toward developing novel near-infrared (NIR)-absorbing nanomaterials, improvement in therapeutic efficiency remains a formidable challenge in photothermal cancer therapy. This study aims to synthesize a specific peptide conjugated polydopamine-modified reduced graphene oxide (pDA/rGO) nanocomposite that promotes the bystander effect to facilitate cancer treatment using NIR-activated photothermal therapy. To prepare a nanoplatform capable of promoting the bystander effect in cancer cells, we immobilized antiarrhythmic peptide 10 (AAP10) on the surface of dopamine-modified rGO (AAP10-pDA/rGO). Our AAP10-pDA/rGO could promote the bystander effect by increasing the expression of connexin 43 protein in MCF-7 breast-cancer cells. Because of its tremendous ability to absorb NIR absorption, AAP10-pDA/rGO offers a high photothermal effect under NIR irradiation. This leads to a massive death of MCF-7 cells via the bystander effect. Using tumor-bearing mice as the model, it is found that NIR radiation effectively ablates breast tumor in the presence of AAP10-pDA/rGO and inhibits tumor growth by ≈100%. Therefore, this research integrates the bystander and photothermal effects into a single nanoplatform in order to facilitate an efficient photothermal therapy. Furthermore, our AAP10-pDA/rGO, which exhibits both hyperthermia and the bystander effect, can prevent breast-cancer recurrence and, therefore, has great potential for future clinical and research applications.

  13. Bystander Action in Situations of Dating and Sexual Aggression: A Mixed Methodological Study of High School Youth.

    Science.gov (United States)

    Edwards, Katie M; Rodenhizer-Stämpfli, Kara Anne; Eckstein, Robert P

    2015-12-01

    Bystander action is a critical component of dating and sexual aggression prevention; however, little is known about barriers and facilitators of bystander action among high school youth and in what situations youth are willing to engage in bystander action. The current study examined bystander action in situations of dating and sexual aggression using a mixed methodological design. Participants included primarily Caucasian (83.0%, n = 181) male (54.6%, n = 119) and female (44.5%, n = 97) high school youth (N = 218). Most (93.6%) students had the opportunity to take action during the past year in situations of dating or sexual aggression; being female and histories of dating and sexual aggression related to bystander action. Thematic analysis of the focus group data identified barriers (e.g., the aggression not meeting a certain threshold, anticipated negative consequences) to bystander action, as well as insight on promising forms of action (e.g., verbally telling the perpetrator to stop, getting a teacher); problematic intervention methods (e.g., threatening or using physical violence to stop the perpetrator) were also noted. Implications for programming are discussed.

  14. Recognition of competitors by male golden hamsters.

    Science.gov (United States)

    Petrulis, Aras; Weidner, Molly; Johnston, Robert E

    2004-06-01

    Golden hamsters, like many animals, form dominant/subordinate relationships after aggressive encounters. We examined whether behavioral responses by males that won or lost fights would differ toward familiar and unfamiliar male stimulus animals. In Experiment 1, male winners or losers of fights explored an arena containing a confined stimulus animal that was either familiar or novel and had either won or lost a fight. Compared to dominant males, losers spent less time in proximity to stimulus males and investigated them less. Losers also displayed higher levels of stretch-attend postures (indicative of risk assessment) than winners, and they showed more escape and locomotion in response to familiar winners than to unfamiliar winners, indicating recognition of the male that they had lost to. In Experiment 2, losers scent marked less to the odors of a familiar winner than to those of an unfamiliar winner. Thus, male hamsters appear to use familiarity with a former opponent's odors to adaptively regulate their responses to variations in social threat.

  15. ABSCESSO TESTICULAR EM HAMSTER: RELATO DE CASO

    Directory of Open Access Journals (Sweden)

    R. M. Santos

    2012-12-01

    Full Text Available The Hamster, rodent originating from the Middle East, is a species studied along with other laboratory animals as experimental models in scientific papers and currently is also created as a pet, by virtue of being docile, easy to handle and require little space for survival. The suppurative processes in domestic animals are relatively frequent. Due to infectious diseases or purulent course of aggressiveness of the environment in which they live. The habit of storing food in the cheeks with sharp edges can injure the skin and often cause abscesses in this species. However, other lesions may lead to suppuration, diseases such as testicular tumor or no tumor or not produced by damage in the skin, leading to tumescence (VITAL et al., 2007. This article reports a case of a hamster treated at the Veterinary Hospital of FAFRAM with clinical history of discomfort, anorexia and frequent licking of the scrotum. On clinical examination it was found by aspiration of purulent secretions and the presence of large numbers of polymorphonuclear cells on cytology, diagnosed with testicular abscess. The animal was taken to the operating room where was performed conventional bilateral orchiectomy and total excision of the abscess by opening the tunica vaginalis and ligation of the spermatic cord. Postoperative care included antibiotic therapy with enrofloxacin and use of an anti-inflammatory meloxicam. After ten days the stitches were removed, the wound was healing satisfactorily and the animal was in good health.O Hamster, roedor originário do Oriente Médio, é uma espécie estudada juntamente com outros animais de laboratório como modelo experimental em trabalhos científicos e, atualmente, também é criado como animal de companhia, em virtude de ser dócil, de fácil manuseio e necessitar de pequeno espaço para sobrevivência. Os processos supurativos nos animais domésticos são relativamente frequentes. Em decorrência de doenças infectocontagiosas de

  16. Cyclooxygenase-2 Expression in Hamster and Human Pancreatic Neoplasia

    Directory of Open Access Journals (Sweden)

    Pamela L. Crowell

    2006-06-01

    Full Text Available Cyclooxygenase-2 (COX-2 has been implicated in the development of gastrointestinal malignancies. The aim of the present study was to determine COX-2 expression/activity throughout stages of experimental and human pancreatic neoplasia. COX-2 immunohistochemistry was performed in pancreata of hamsters subjected to the carcinogen N-nitrosobis-(2-oxopropylamine (BOP and in human pancreatic tumors. COX-2 activity was determined by prostaglandin E2 assay in tumor versus matched normal pancreatic tissues. The activity of the COX inhibitor sulindac was tested in the PC-1 hamster pancreatic cancer model. COX-2 expression was elevated in all pancreatic intraepithelial neoplasias (PanINs and adenocarcinomas. In BOP-treated hamsters, there were significant progressive elevations in COX-2 expression throughout pancreatic tumorigenesis. In human samples, peak COX-2 expression occurred in PanIN2 lesions and remained moderately elevated in PanIN3 and adenocarcinoma tissues. COX-2 activity was significantly elevated in hamster and human pancreatic cancers compared to pair-matched normal pancreas. Furthermore, hamster pancreatic tumor engraftment/formation in the PC-1 hamster pancreatic cancer model was reduced 4.9-fold by oral administration of sulindac. Increased COX-2 expression is an early event in pancreatic carcinogeneses. The BOP-induced hamster carcinogenesis model is a representative model used to study the role of COX-2 in well-differentiated pancreatic tumorigenesis. COX inhibitors may have a role in preventing tumor engraftment/formation.

  17. The effect of victims' responses to overt bullying on same-sex peer bystander reactions.

    Science.gov (United States)

    Sokol, Nicole; Bussey, Kay; Rapee, Ronald M

    2015-10-01

    This study investigated the impact of victims' responses to overt bullying on peer bystanders' attitudes and reactions. Fifth- and seventh-grade students (N = 206; M(age) = 11.13 and 13.18 years, respectively) completed online questionnaires about gender-consistent videotaped hypothetical bullying scenarios in which the victims' responses (angry, sad, confident, ignoring) were experimentally manipulated. Victims' responses significantly influenced bystanders' attitudes towards the victim, perceptions of the victimization, emotional reactions, and behavioral intentions. In general, angry victims elicited more negative reactions, sad victims elicited greater intentions to act, while incidents involving confident victims were perceived as less serious. Several variations depending on the bullying type and students' grade, gender, and personal experiences with bullying were evident. Implications for individual-level and peer-level anti-bullying interventions are discussed.

  18. Bystanders matter: associations between reinforcing, defending, and the frequency of bullying behavior in classrooms.

    Science.gov (United States)

    Salmivalli, Christina; Voeten, Marinus; Poskiparta, Elisa

    2011-01-01

    This study investigated whether the bystanders' behaviors (reinforcing the bully vs. defending the victim) in bullying situations are related to the frequency of bullying in a classroom. The sample consisted of 6,764 primary school children from Grades 3 to 5 (9-11 years of age), who were nested within 385 classrooms in 77 schools. The students filled out Internet-based questionnaires in their schools' computer labs. The results from multilevel models showed that defending the victim was negatively associated with the frequency of bullying in a classroom, whereas the effect of reinforcing the bully was positive and strong. The results suggest that bystander responses influence the frequency of bullying, which makes them suitable targets for antibullying interventions.

  19. Chimpanzees' Bystander Reactions to Infanticide: An Evolutionary Precursor of Social Norms?

    Science.gov (United States)

    von Rohr, Claudia Rudolf; van Schaik, Carel P; Kissling, Alexandra; Burkart, Judith M

    2015-06-01

    Social norms-generalized expectations about how others should behave in a given context-implicitly guide human social life. However, their existence becomes explicit when they are violated because norm violations provoke negative reactions, even from personally uninvolved bystanders. To explore the evolutionary origin of human social norms, we presented chimpanzees with videos depicting a putative norm violation: unfamiliar conspecifics engaging in infanticidal attacks on an infant chimpanzee. The chimpanzees looked far longer at infanticide scenes than at control videos showing nut cracking, hunting a colobus monkey, or displays and aggression among adult males. Furthermore, several alternative explanations for this looking pattern could be ruled out. However, infanticide scenes did not generally elicit higher arousal. We propose that chimpanzees as uninvolved bystanders may detect norm violations but may restrict emotional reactions to such situations to in-group contexts. We discuss the implications for the evolution of human morality.

  20. Torpor shortens the period of Siberian hamster circadian rhythms.

    Science.gov (United States)

    Thomas, E M; Jewett, M E; Zucker, I

    1993-10-01

    We investigated the influence of ambient and body temperature (Ta and Tb) on circadian rhythms of gonadectomized male Siberian hamsters. Animals that entered torpor (Tb circadian periods (tau s) than did nontorpid hamsters at a Ta of 13 degrees C (24.17 +/- 0.05 vs. 24.33 +/- 0.04 h). The tau s of homeothermic hamsters were not affected by Ta change. Short-term decreases in Tb, rather than changes in Ta, appear to affect tau. Access to activity wheels inhibited expression of torpor in short daylengths and was associated with significant increases in body mass. Running wheel activity can mask or block specific short-day responses.

  1. Bioavailability and disposition of solanine in rats and hamsters

    OpenAIRE

    Groen K; Pereboom-de Fauw DPKH; Besamusca P; Beekhof PK; Speijers GJA; Derks HJGM

    1992-01-01

    The toxicokinetics of [3H]-alpha-solanine after oral (po) and intravenous (iv) administration in rats and hamsters were studied, in order to decide which is the most appropriate model in risk assessment studies. The iv dose was 54 mug/kg; the oral dose was 170 mug/kg. After iv administration, the toxicokinetics of total radioactivity in blood were comparable in rats and hamsters. However, the clearance of total radioactivity from plasma was more effective in rats than in hamsters The half-liv...

  2. The key role of miR-21-regulated SOD2 in the medium-mediated bystander responses in human fibroblasts induced by α-irradiated keratinocytes

    Energy Technology Data Exchange (ETDEWEB)

    Tian, Wenqian; Yin, Xiaoming; Wang, Longxiao; Wang, Jingdong; Zhu, Wei; Cao, Jianping [School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Yang, Hongying, E-mail: yanghongying@suda.edu.cn [School of Radiation Medicine and Protection, Medical College of Soochow University/Collaborative Innovation Center of Radiation Medicine of Jiangsu Higher Education Institutions, 199 Renai Road, Suzhou Industrial Park, Suzhou, Jiangsu Province 215123 (China); Institute of Radiotherapy & Oncology, Soochow University (China)

    2015-10-15

    Highlights: • After co-culture with α-irradiated HaCaT cells, WS1 cells displayed oxidative stress and DNA damage. • Increased miR-21 expression in bystander cells was critical to the occurrence of RIBEs. • SOD2 of bystander cells played an important role in bystander responses. • miR-21 mediated bystander effects through its regulation on SOD2. - Abstract: Radiation-induced bystander effect (RIBE) is well accepted in the radiation research field by now, but the underlying molecular mechanisms for better understanding this phenomenon caused by intercellular communication and intracellular signal transduction are still incomplete. Although our previous study has demonstrated an important role of miR-21 of unirradiated bystander cells in RIBEs, the direct evidence for the hypothesis that RIBE is epigenetically regulated is still limited and how miR-21 mediates RIBEs is unknown. Reactive oxygen species (ROS) have been demonstrated to be involved in RIBEs, however, the roles of anti-oxidative stress system of cells in RIBEs are unclear. Using transwell insert co-culture system, we investigated medium-mediated bystander responses in WS1 human fibroblasts after co-culture with HaCaT keratinocytes traversed by α-particles. Results showed that the ROS levels in unirradiated bystander WS1 cells were significantly elevated after 30 min of co-culture, and 53BP1 foci, a surrogate marker of DNA damage, were obviously induced after 3 h of co-culture. This indicates the occurrence of oxidative stress and DNA damage in bystander WS1 cells after co-culture with irradiated keratinocytes. Furthermore, the expression of miR-21 was increased in bystander WS1 cells, downregulation of miR-21 eliminated the bystander responses, overexpression of miR-21 alone could induce bystander-like oxidative stress and DNA damage in WS1 cells. These data indicate an important mediating role of miR-21 in RIBEs. In addition, MnSOD or SOD2 in WS1 cells was involved in the bystander effects

  3. Modulation of modeled microgravity on radiation-induced bystander effects in Arabidopsis thaliana

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Ting [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Sun, Qiao [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Xu, Wei; Li, Fanghua [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Li, Huasheng; Lu, Jinying [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Wu, Lijun; Wu, Yuejin [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China); Liu, Min [Space Molecular Biological Lab, China Academy of Space Technology, Beijing 100086 (China); Bian, Po [Key Laboratory of Ion Beam Bio-engineering, Hefei Institutes of Physical Science, Chinese Academy of Sciences and Anhui Province, Hefei, Anhui 230031 (China)

    2015-03-15

    Highlights: • The effects of microgravity on the radiation-induced bystander effects (RIBE) were definitely demonstrated. • The effects of microgravity on RIBE might be divergent for different biological events. • The microgravity mainly modified the generation or transport of bystander signals at early stage. - Abstract: Both space radiation and microgravity have been demonstrated to have inevitable impact on living organisms during space flights and should be considered as important factors for estimating the potential health risk for astronauts. Therefore, the question whether radiation effects could be modulated by microgravity is an important aspect in such risk evaluation. Space particles at low dose and fluence rate, directly affect only a fraction of cells in the whole organism, which implement radiation-induced bystander effects (RIBE) in cellular response to space radiation exposure. The fact that all of the RIBE experiments are carried out in a normal gravity condition bring forward the need for evidence regarding the effect of microgravity on RIBE. In the present study, a two-dimensional rotation clinostat was adopted to demonstrate RIBE in microgravity conditions, in which the RIBE was assayed using an experimental system of root-localized irradiation of Arabidopsis thaliana (A. thaliana) plants. The results showed that the modeled microgravity inhibited significantly the RIBE-mediated up-regulation of expression of the AtRAD54 and AtRAD51 genes, generation of reactive oxygen species (ROS) and transcriptional activation of multicopy P35S:GUS, but made no difference to the induction of homologous recombination by RIBE, showing divergent responses of RIBE to the microgravity conditions. The time course of interaction between the modeled microgravity and RIBE was further investigated, and the results showed that the microgravity mainly modulated the processes of the generation or translocation of the bystander signal(s) in roots.

  4. Teens’ Self-Efficacy to Deal with Dating Violence as Victim, Perpetrator or Bystander

    OpenAIRE

    Van Camp, T.; Hébert, M; E. Guidi; Lavoie, F.; M. Blais

    2014-01-01

    Multiple studies have demonstrated that adolescent dating violence is highly prevalent and associated with internalizing and externalizing problems. A number of prevention initiatives are being implemented in North-American high schools. Such initiatives do not only aim to raise awareness among potential victims and offenders but also among peer bystanders. Since teenagers mainly reach out to their peers when experiencing adversity, it is important to address adolescents’ efficiency to deal w...

  5. What is the role of the bystander response in radionuclide therapies?

    Directory of Open Access Journals (Sweden)

    Darren eBrady

    2013-08-01

    Full Text Available Radionuclide therapy for cancer is undergoing a renaissance, with a wide range of radionuclide and clinical delivery systems currently under investigation. Dosimetry at the cellular and subcellular level is complex with inhomogeneity and incomplete targeting of all cells such that some tumour cells will receive little or no direct radiation energy. There is now sufficient preclinical evidence of a bystander response which can modulate the biology of these unirradiated cells with current research demonstrating both protective and inhibitory responses. Dependence upon fraction of irradiated cells has also been found has and the presence of functional gap junctions appears to be import for several bystander responses. The selection of either high or low LET radionuclides may be critical. While low LET radionuclides appear to have a bystander response proportional to dose, the dose-response from high LET radionuclides are more complex. In media transfer experiments a U shaped response curve has been demonstrated for high LET treatments. However this U shaped response has not been seen with co-culture experiments and its relevance remains uncertain. For high LET treatments there is a suggestion that dose rate effects may also be important with inhibitory effects noted with 125I labelling study and a stimulatory seen with 123I labelling in one study.

  6. It's Not My Place: Formative Evaluation Research to Design a Bystander Intervention Campaign.

    Science.gov (United States)

    DeMaria, Andrea L; Sundstrom, Beth; Grzejdziak, Maja; Booth, Kathleen; Adams, Helen; Gabel, Colby; Cabot, Jeri

    2015-10-07

    Sexual misconduct remains a problem on college campuses despite years of documentation and research, and program development and implementation. The purpose of this study was to conduct systematic theory-based formative audience research to understand how college women and men make meaning of sexual assault and bystander intervention. A total of 69 men and women aged 18 to 24 years participated in eight gender-specific focus group discussions. A grounded theory approach was used to identify patterns and themes across the data. Themes emerging from the data included the following: (a) female participants' experiences of sexism and misogyny, (b) the myth that rape is falsely reported, (c) complex understandings of consent and entitlement, (d) the reluctance to stop someone from having a "good time," (e) the role of alcohol as a moderating factor in sexual misconduct and bystander intervention, and (f) preference for direct and impactful messaging. This study informs researchers and practitioners about college students' perceptions of, and experiences with, bystander intervention and sexual assault. Practitioners can use this information to develop effective mixed media, campus-wide social marketing campaigns.

  7. Differential effects of p53 on bystander phenotypes induced by gamma ray and high LET heavy ion radiation

    Science.gov (United States)

    He, Mingyuan; Dong, Chen; Konishi, Teruaki; Tu, Wenzhi; Liu, Weili; Shiomi, Naoko; Kobayashi, Alisa; Uchihori, Yukio; Furusawa, Yoshiya; Hei, Tom K.; Dang, Bingrong; Shao, Chunlin

    2014-04-01

    High LET particle irradiation has several potential advantages over γ-rays such as p53-independent response. The purpose of this work is to disclose the effect of p53 on the bystander effect induced by different LET irradiations and underlying mechanism. Lymphocyte cells of TK6 (wild type p53) and HMy2.CIR (mutated p53) were exposed to either low or high LET irradiation, then their mitochondrial dysfunction and ROS generation were detected. The micronuclei (MN) induction in HL-7702 hepatocytes co-cultured with irradiated lymphocytes was also measured. It was found that the mitochondrial dysfunction, p66Shc activation, and intracellular ROS were enhanced in TK6 but not in HMy2.CIR cells after γ-ray irradiation, but all of them were increased in both cell lines after carbon and iron irradiation. Consistently, the bystander effect of MN formation in HL-7702 cells was only triggered by γ-irradiated TK6 cells but not by γ-irradiated HMy2.CIR cells. But this bystander effect was induced by both lymphocyte cell lines after heavy ion irradiation. PFT-μ, an inhibitor of p53, only partly inhibited ROS generation and bystander effect induced by 30 keV/μm carbon-irradiated TK6 cells but failed to suppress the bystander effect induced by the TK6 cells irradiated with either 70 keV/μm carbon or 180 keV/μm iron. The mitochondrial inhibitors of rotenone and oligomycin eliminated heavy ion induced ROS generation in TK6 and HMy2.CIR cells and hence diminished the bystander effect on HL-7702 cells. These results clearly demonstrate that the bystander effect is p53-dependent for low LET irradiation, but it is p53-independent for high LET irradiation which may be because of p53-independent ROS generation due to mitochondrial dysfunction.

  8. Neuropeptide Y induces torpor-like hypothermia in Siberian hamsters.

    Science.gov (United States)

    Paul, Matthew J; Freeman, David A; Park, Jin Ho; Dark, John

    2005-09-01

    Intracerebroventricular (ICV) injections of neuropeptide Y (NPY) are known to decrease body temperature (Tb) of laboratory rats by 1-3 degrees C. Several NPY pathways in the brain terminate in hypothalamic structures involved in energy balance and thermoregulation. Laboratory rats are homeothermic, maintaining Tb within a narrow range. We examined the effect of ICV injected NPY on Tb in the heterothermic Siberian hamster (Phodopus sungorus), a species that naturally undergoes daily torpor in which Tb decreases by as much as 15-20 degrees C. Minimum effective dose was determined in preliminary testing then various doses of NPY were tested in cold-acclimated Siberian hamsters while food was withheld. NPY markedly reduced Tb in the heterothermic Siberian hamster. In addition, the reduction in Tb in 63% of the observations was sufficient to reach the criterion for daily torpor (Tb Siberian hamster. NPY treatment may be activating hypothalamic systems that normally integrate endogenous torpor-producing signals and initiate torpor.

  9. A study of the carcinogenicity of glycidol in Syrian hamsters.

    Science.gov (United States)

    Lijinsky, W; Kovatch, R M

    1992-01-01

    The industrial chemical glycidol is a directly acting mutagen and a broadly acting carcinogen in rats. It was administered to Syrian golden hamsters (20 male and 20 female) by gavage of 12 mg twice a week for 60 weeks. The total dose per animal was 1.45 g or 20 mmol. Survival was not different from control hamsters treated with corn oil/ethyl acetate. Of the treated males, 9 had tumors and 13 of the treated females had tumors, some of which were adrenal cortex tumors seen in controls. More tumors were seen in the glycidol-treated hamsters than in controls, but the spleen was the only notable target organ and the number of animals with spleen hemangiosarcomas was small. Glycidol appeared to be less carcinogenic in hamsters than in rats or mice.

  10. Photon hormesis deactivates alpha-particle induced bystander effects between zebrafish embryos

    Science.gov (United States)

    Ng, C. Y. P.; Cheng, S. H.; Yu, K. N.

    2017-04-01

    In the present work, we studied the effects of low-dose X-ray photons on the alpha-particle induced bystander effects between embryos of the zebrafish, Danio rerio. The effects on the naive whole embryos were studied through quantification of apoptotic signals (amounts of cells undergoing apoptosis) at 24 h post fertilization (hpf) using vital dye acridine orange staining, followed by counting the stained cells under a fluorescent microscope. We report data showing that embryos at 5 hpf subjected to a 4.4 mGy alpha-particle irradiation could release a stress signal into the medium, which could induce bystander effect in partnered naive embryos sharing the same medium. We also report that the bystander effect was deactivated when the irradiated embryos were subjected to a concomitant irradiation of 10 or 14 mGy of X-rays, but no such deactivation was achieved if the concomitant X-ray dose dropped to 2.5 or 5 mGy. In the present study, the significant drop in the amount of apoptotic signals on the embryos having received 4.4 mGy alpha particles together X-rays irradiation from 2.5 or 5 mGy to 10 or 14 mGy, together with the deactivation of RIBE with concomitant irradiation of 10 or 14 mGy of X-rays supported the participation of photon hormesis with an onset dose between 5 and 10 mGy, which might lead to removal of aberrant cells through early apoptosis or induction of high-fidelity DNA repair. As we found that photons and alpha particles could have opposite biological effects when these were simultaneously irradiated onto living organisms, these ionizing radiations could be viewed as two different environmental stressors, and the resultant effects could be regarded as multiple stressor effects. The present work presented the first study on a multiple stressor effect which occurred on bystander organisms. In other words, this was a non-targeted multiple stressor effect. The photon hormesis could also explain some failed attempts to observe neutron-induced bystander

  11. Genitourinary changes in hamsters infected and reinfected with Trypanosoma cruzi

    OpenAIRE

    Cabrine-Santos Marlene; Santos Vitorino Modesto dos; Lima Marcus Aurelho; Abreu Marta Elena Araújo de; Lages-Silva Eliane; Ramírez Luís Eduardo

    2003-01-01

    Authors describe genitourinary changes in male hamsters infected and reinfected with Trypanosoma cruzi. Changes in genital organs have been described in human and in experimental chagasic infection. Genital dysfunctions in chronic chagasic patients affect ejaculation, libido and sexual potency, and testis biopsies may show arrested maturation of germ cells, oligozoospermia and azoospermia. Sixty-five male hamsters were inoculated and reinoculated with 2x10³ trypomastigotes of T. cruzi VIC str...

  12. The Significance of the Bystander Effect: Modeling, Experiments, and More Modeling

    Energy Technology Data Exchange (ETDEWEB)

    Brenner, David J.

    2009-07-22

    Non-targeted (bystander) effects of ionizing radiation are caused by intercellular signaling; they include production of DNA damage and alterations in cell fate (i.e. apoptosis, differentiation, senescence or proliferation). Biophysical models capable of quantifying these effects may improve cancer risk estimation at radiation doses below the epidemiological detection threshold. Understanding the spatial patterns of bystander responses is important, because it provides estimates of how many bystander cells are affected per irradiated cell. In a first approach to modeling of bystander spatial effects in a three-dimensional artificial tissue, we assumed the following: (1) The bystander phenomenon results from signaling molecules (S) that rapidly propagate from irradiated cells and decrease in concentration (exponentially in the case of planar symmetry) as distance increases. (2) These signals can convert cells to a long-lived epigenetically activated state, e.g. a state of oxidative stress; cells in this state are more prone to DNA damage and behavior alterations than normal and therefore exhibit an increased response (R) for many end points (e.g. apoptosis, differentiation, micronucleation). These assumptions were implemented by a mathematical formalism and computational algorithms. The model adequately described data on bystander responses in the 3D system using a small number of adjustable parameters. Mathematical models of radiation carcinogenesis are important for understanding mechanisms and for interpreting or extrapolating risk. There are two classes of such models: (1) long-term formalisms that track pre-malignant cell numbers throughout an entire lifetime but treat initial radiation dose-response simplistically and (2) short-term formalisms that provide a detailed initial dose-response even for complicated radiation protocols, but address its modulation during the subsequent cancer latency period only indirectly. We argue that integrating short- and long

  13. Regulation of tonic gonadotropin release in prepubertal female hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Smith, S.G.; Matt, K.S.; Prestowitz, W.F.; Stetson, M.H.

    1982-04-01

    Basal serum gonadotropin levels were monitored weekly in female hamsters from birth to 10 weeks of age. Hamsters raised on three different photoperiods presented uniform pre- and postpubertal patterns of serum LH and FSH, suggesting that gonadotropin release in the young hamster occurs independently of ambient photoperiod. In all groups, serum LH levels increased gradually in animals up to 4 weeks of age, after which levels plateaued at 50--100 ng/ml. Serum FSH was markedly elevated in 2- and 3-week-old hamsters (800--1200 ng/ml), but remained at 200--400 ng/ml in all other groups. We next examined the change in the responsiveness of the pituitary to exogenous gonadotropin-releasing hormone (GnRH) challenge. Female hamsters 2 days of age failed to respond to any dose (0.025--1000 ng) of GnRH, while 10-day old females responded in typical dose-dependent fashion. GnRH-stimulated LH release first occurred in 6-day-old hamsters and was maximal by day 9, whereas FSH release first occurred on day 8 and was maximal by day 9. The prepubertal pattern of gonadotropin release can, in part, be explained on the basis of the development of pituitary GnRH sensitivity, which occurs independently of photoperiod.

  14. [Induction of protective antiamebic immunity in hamsters with heterologous antigens].

    Science.gov (United States)

    Jiménez Cardoso, J M; Jiménez, E; de Jesús Bernal, M; Kumate, J

    1989-01-01

    Two hundred and twenty-five Syrian golden hamsters were used. Twenty five of them served as the control group. All other hamsters were intradermal immunized, once a week for four weeks, with a mixture of amebic proteins, mixed with complete Freund adjuvant, obtained from 5 x 10(5) homogenized dead amebic trophozoites from five different strains. Each group of hamsters (five groups of 40 animals each) were immunized with one of the following strains: E. histolytica HM-531, HJ-1, HM1-IMSS, E. chattoni PM-4 and PM-5. All hamsters, including those from the control group, were later inoculated with 0.2 mL equivalent to 1 x 10(5) live trophozoites from the different strains grown in axenic TYI-S-33 medium. Inoculation was performed by direct injection into the liver. The hamsters were sacrificed eight days later and their livers examined. All non-immunized animals showed extensive gross hepatic nodular abscesses. The liver of immunized hamsters showed mild to moderate lesions: the histopathological striking feature was non-specific granulomata. It is concluded that the immunized animals inoculated with homologous stock showed protective immunity to amebic infections. In other cases, immunity was seen though they were inoculated with a heterologous stock.

  15. Sulfasalazine unveils a contact-independent HSV-TK/ganciclovir gene therapy bystander effect in malignant gliomas.

    Science.gov (United States)

    Robe, Pierre A; Nguyen-Khac, Minh-Tuan; Lambert, Frederic; Lechanteur, Chantal; Jolois, Olivier; Ernst-Gengoux, Patricia; Rogister, Bernard; Bours, Vincent

    2007-01-01

    The efficacy of HSV-TK/ganciclovir-based gene therapy on malignant gliomas largely relies on the amplitude of the bystander effect. In these experiments, the anti-inflammatory drug Sulfasalazine increased the HSV-TK/ganciclovir bystander effect in C6, 9L and LN18 cells but not in U87 glioma cells. Using bi-compartmental culture devices and conditioned medium transfer experiments, we showed that in C6, 9L and LN18 cells but not in U87 cells, Sulfasalazine also unveiled a new, contact-independent mechanism of HSV-TK/ganciclovir bystander effect. Upon treatment with ganciclovir, human LN18-TK but not U87-TK cells synthetized and released TNF-alpha in the culture medium. Sulfasalazine sensitized glioma cells to the toxic effect of TNF-alpha and enhanced its secretion in LN18-TK cells in response to GCV treatment. The caspase-8 inhibitor Z-IETD-FMK and a blocking antibody to TNF-alpha both inhibited the contact-independent bystander effect in LN18 cells. Taken together, these results suggest that TNF-alpha mediates the contact-independent bystander effect in LN18 cells. The treatment with GCV and/or Sulfasalazine of tumor xenografts consisting of a mix of 98% C6 and 2% C6-TK cells shows that Sulfasalazine is also a potent adjunct to the in vivo treatment of gliomas.

  16. Bystander Position Taking in School Bullying: The Role of Positive Identity, Self-Efficacy, and Self-Determination

    Directory of Open Access Journals (Sweden)

    Sandra K. M. Tsang

    2011-01-01

    Full Text Available School bullying has become an explicit, burgeoning problem challenging the healthy development of children and adolescents in Hong Kong. Many bullying prevention and intervention programs focus on victims and bullies, with bystanders treated as either nonexistent or irrelevant. This paper asserts that bystanders actually play pivotal roles in deciding whether the bullying process and dynamics are benign or adversarial. Bystanders' own abilities and characteristics often influence how they respond to victims and bullies. “P.A.T.H.S. to Adulthood: A Jockey Club Youth Enhancement Scheme” (P.A.T.H.S. = Positive Adolescent Training through Holistic Social Programmes is an evidence-based positive youth development program which shows that primary intervention programs have constructive impacts on junior secondary school students' beliefs and behavior. This paper asserts that intrapsychic qualities, namely identity, self-efficacy, and self-determination, greatly influence how bystanders react in school bullying situations. The paper also explains how classroom-based educational programs based on the P.A.T.H.S. model have been designed to help junior secondary school students strengthen these characteristics, so that they can be constructive bystanders when they encounter school bullying.

  17. Bystander position taking in school bullying: the role of positive identity, self-efficacy, and self-determination.

    Science.gov (United States)

    Tsang, Sandra K M; Hui, Eadaoin K P; Law, Bella C M

    2011-01-01

    School bullying has become an explicit, burgeoning problem challenging the healthy development of children and adolescents in Hong Kong. Many bullying prevention and intervention programs focus on victims and bullies, with bystanders treated as either nonexistent or irrelevant. This paper asserts that bystanders actually play pivotal roles in deciding whether the bullying process and dynamics are benign or adversarial. Bystanders' own abilities and characteristics often influence how they respond to victims and bullies. "P.A.T.H.S. to Adulthood: A Jockey Club Youth Enhancement Scheme" (P.A.T.H.S. = Positive Adolescent Training through Holistic Social Programmes) is an evidence-based positive youth development program which shows that primary intervention programs have constructive impacts on junior secondary school students' beliefs and behavior. This paper asserts that intrapsychic qualities, namely identity, self-efficacy, and self-determination, greatly influence how bystanders react in school bullying situations. The paper also explains how classroom-based educational programs based on the P.A.T.H.S. model have been designed to help junior secondary school students strengthen these characteristics, so that they can be constructive bystanders when they encounter school bullying.

  18. Educating for Justice: Creating a Mission-Driven Model of Bystander Intervention to Address Sexual Violence at U.S. Catholic Colleges and Universities

    Science.gov (United States)

    Galarneau, Joy; O'Neill, Shannon

    2015-01-01

    This article presents bystander intervention education as a best-practice approach to sexual violence prevention in college settings. It draws out a connection between mission-specific resources that can be used to advance the prevention agenda, while examining how bystander intervention education can deepen community engagement in collegiate…

  19. Social thermoregulation and torpor in the Siberian hamster.

    Science.gov (United States)

    Jefimow, Małgorzata; Głabska, Marta; Wojciechowski, Michał S

    2011-04-01

    Social thermoregulation and huddling bring about energy benefits to animals sharing a nest because of the smaller surface-to-volume ratio of a huddle and the higher local temperature in the nest. We tested whether living in groups and huddling affect daily torpor, metabolic rate and seasonal changes in the body mass of a small heterothermic rodent, the Siberian hamster (Phodopus sungorus), housed under semi-natural conditions both singly and in groups of four litter-mates. We predicted that in hamsters housed in groups: (1) synchronized torpor bouts would be longer and deeper than non-synchronized ones but shallower than in solitary hamsters, (2) seasonal variations in metabolic rate would be lower than in solitary hamsters, and (3) the winter decrease in body mass would be smaller in grouped than in singly housed hamsters. We found that group housing led to a smaller decrease in body mass in winter, and affected the length and depth of daily torpor. In group-living hamsters more than 50% of all torpor episodes were synchronized and torpid animals were often found in huddles formed of all cage-mates. The longest and deepest torpor bouts in groups were recorded when all animals in a group entered torpor simultaneously. Although the minimum body temperature during torpor was higher, torpor duration was slightly longer than in solitary hamsters. We did not record significant differences in the body mass-adjusted rate of oxygen consumption between solitary and grouped animals, either in the cold or at the lower critical temperature. We conclude that social thermoregulation enables maintenance of a larger body mass, and thus a larger body fat content, which can ensure better body condition at the beginning of the reproductive season.

  20. Reciprocal bystander effect between α-irradiated macrophage and hepatocyte is mediated by cAMP through a membrane signaling pathway.

    Science.gov (United States)

    He, Mingyuan; Dong, Chen; Xie, Yuexia; Li, Jitao; Yuan, Dexiao; Bai, Yang; Shao, Chunlin

    2014-01-01

    Irradiated cells can induce biological effects on vicinal non-irradiated bystander cells, meanwhile the bystander cells may rescue the irradiated cells through a feedback signal stress. To elucidate the nature of this reciprocal effect, we examined the interaction between α-irradiated human macrophage cells U937 and its bystander HL-7702 hepatocyte cells using a cell co-culture system. Results showed that after 6h of cell co-culture, mitochondria depolarization corresponding to apoptosis was significantly induced in the HL-7702 cells, but the formation of micronuclei in the irradiated U937 cells was markedly decreased compared to that without cell co-culture treatment. This reciprocal effect was not observed when the cell membrane signaling pathway was blocked by filipin that inhibited cAMP transmission from bystander cells to irradiated cells. After treatment of cells with exogenous cAMP, forskolin (an activator of cAMP) or KH-7 (an inhibitor of cAMP), respectively, it was confirmed that cAMP communication from bystander cells to targeted cells could mitigate radiation damage in U739 cells, and this cAMP insufficiency in the bystander cells contributed to the enhancement of bystander apoptosis. Moreover, the bystander apoptosis in HL-7702 cells was aggravated by cAMP inhibition but it could not be evoked when p53 of HL-7702 cells was knocked down no matter of forskolin and KH-7 treatment. In conclusion, this study disclosed that cAMP could be released from bystander HL-7702 cells and compensated to α-irradiated U937 cells through a membrane signaling pathway and this cAMP communication played a profound role in regulating the reciprocal bystander effects.

  1. Bystander responses to a violent incident in an immersive virtual environment.

    Science.gov (United States)

    Slater, Mel; Rovira, Aitor; Southern, Richard; Swapp, David; Zhang, Jian J; Campbell, Claire; Levine, Mark

    2013-01-01

    Under what conditions will a bystander intervene to try to stop a violent attack by one person on another? It is generally believed that the greater the size of the crowd of bystanders, the less the chance that any of them will intervene. A complementary model is that social identity is critical as an explanatory variable. For example, when the bystander shares common social identity with the victim the probability of intervention is enhanced, other things being equal. However, it is generally not possible to study such hypotheses experimentally for practical and ethical reasons. Here we show that an experiment that depicts a violent incident at life-size in immersive virtual reality lends support to the social identity explanation. 40 male supporters of Arsenal Football Club in England were recruited for a two-factor between-groups experiment: the victim was either an Arsenal supporter or not (in-group/out-group), and looked towards the participant for help or not during the confrontation. The response variables were the numbers of verbal and physical interventions by the participant during the violent argument. The number of physical interventions had a significantly greater mean in the in-group condition compared to the out-group. The more that participants perceived that the Victim was looking to them for help the greater the number of interventions in the in-group but not in the out-group. These results are supported by standard statistical analysis of variance, with more detailed findings obtained by a symbolic regression procedure based on genetic programming. Verbal interventions made during their experience, and analysis of post-experiment interview data suggest that in-group members were more prone to confrontational intervention compared to the out-group who were more prone to make statements to try to diffuse the situation.

  2. Bystander responses to a violent incident in an immersive virtual environment.

    Directory of Open Access Journals (Sweden)

    Mel Slater

    Full Text Available Under what conditions will a bystander intervene to try to stop a violent attack by one person on another? It is generally believed that the greater the size of the crowd of bystanders, the less the chance that any of them will intervene. A complementary model is that social identity is critical as an explanatory variable. For example, when the bystander shares common social identity with the victim the probability of intervention is enhanced, other things being equal. However, it is generally not possible to study such hypotheses experimentally for practical and ethical reasons. Here we show that an experiment that depicts a violent incident at life-size in immersive virtual reality lends support to the social identity explanation. 40 male supporters of Arsenal Football Club in England were recruited for a two-factor between-groups experiment: the victim was either an Arsenal supporter or not (in-group/out-group, and looked towards the participant for help or not during the confrontation. The response variables were the numbers of verbal and physical interventions by the participant during the violent argument. The number of physical interventions had a significantly greater mean in the in-group condition compared to the out-group. The more that participants perceived that the Victim was looking to them for help the greater the number of interventions in the in-group but not in the out-group. These results are supported by standard statistical analysis of variance, with more detailed findings obtained by a symbolic regression procedure based on genetic programming. Verbal interventions made during their experience, and analysis of post-experiment interview data suggest that in-group members were more prone to confrontational intervention compared to the out-group who were more prone to make statements to try to diffuse the situation.

  3. Debriefing bystanders of out-of-hospital cardiac arrest is valuable

    DEFF Research Database (Denmark)

    Møller, Thea Palsgaard; Hansen, Carolina Malta; Fjordholt, Martin

    2014-01-01

    , positively influencing the ability to cope with the emotional reactions and the cognitive perception of own performance and motivates improvement of CPR skills. Importantly, it increases confidence to provide CPR in the future. Implementation of telephone debriefing to bystanders at Emergency Medical...... the phenomenological approach. RESULTS: Six themes emerged from analysis of debriefing audio files: (1) identification of OHCA; (2) emotional and perceptual experience with OHCA; (3) collaboration with healthcare professionals; (4) patients outcome; (5) coping with the experience and (6) general reflections. When...

  4. Bringing in the target audience in bystander social marketing materials for communities: suggestions for practitioners.

    Science.gov (United States)

    Potter, Sharyn J; Stapleton, Jane G

    2011-06-01

    The Know Your Power™ social marketing campaign images model active bystander behaviors that target audience members can use in situations where sexual and relationship violence and stalking are occurring, have occurred, or have the potential to occur. In this practitioner note, we describe strategies that we have used to engage target audience members in the development of the social marketing campaign that we hope can be used by practitioners. We give examples from the development and evaluation of the Know Your Power(TM) social marketing campaign that used focus group and other types of feedback from the target audience to inform the direction of the campaign.

  5. Serratia fonticola, pathogen or bystander? A case series and review of the literature

    Directory of Open Access Journals (Sweden)

    Abdullah Aljorayid

    2016-01-01

    We reviewed 17 other patients with clinical cultures positive for S. fonticola. Of these, 11 isolates were from the genitourinary system, most often as part of a polymicrobial culture. The majority of the other organisms recovered were recognized pathogens from the Enterobacteriaceae family. The cases suggest that when recovered in conjunction with other organisms, S. fonticola does not lead to enhanced virulence or worse clinical outcomes and may be a bystander. When detected alone, which is a rare occurrence, S. fonticola may function as a human pathogen.

  6. Apoptosis is signalled early by low doses of ionising radiation in a radiation-induced bystander effect

    Energy Technology Data Exchange (ETDEWEB)

    Furlong, Hayley, E-mail: hayley.furlong@dit.ie [DIT Centre for Radiation and Environmental Science, Focas Research Institute, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland); School of Biological Sciences, College of Sciences and Health, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland); Mothersill, Carmel [Medical Physics and Applied Radiation Sciences, Nuclear Research Building, 1280 Hamilton, Ontario L8S 4K1 (Canada); Lyng, Fiona M. [DIT Centre for Radiation and Environmental Science, Focas Research Institute, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland); Howe, Orla [DIT Centre for Radiation and Environmental Science, Focas Research Institute, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland); School of Biological Sciences, College of Sciences and Health, Dublin Institute of Technology, Kevin St, Dublin 8 (Ireland)

    2013-01-15

    Highlights: ► Molecular mechanisms involved in the production of a radiation induced bystander effect are not well known. ► We investigate gene expression changes in apoptotic genes in both direct and bystander responses. ► We demonstrate initiation of the apoptotic cascade in a bystander response. ► Lower doses reveal a specific but differential response related to apoptosis compared to higher doses. - Abstract: It is known that ionising radiation (IR) induces a complex signalling apoptotic cascade post-exposure to low doses ultimately to remove damaged cells from a population, specifically via the intrinsic pathway. Therefore, it was hypothesised that bystander reporter cells may initiate a similar apoptotic response if exposed to low doses of IR (0.05 Gy and 0.5 Gy) and compared to directly irradiated cells. Key apoptotic genes were selected according to their role in the apoptotic cascade; tumour suppressor gene TP53, pro-apoptotic Bax and anti-apoptotic Bcl2, pro-apoptotic JNK and anti-apoptotic ERK, initiator caspase 2 and 9 and effector caspase 3, 6 and 7. The data generated consolidated the role of apoptosis following direct IR exposure for all doses and time points as pro-apoptotic genes such as Bax and JNK as well as initiator caspase 7 and effector caspase 3 and 9 were up-regulated. However, the gene expression profile for the bystander response was quite different and more complex in comparison to the direct response. The 0.05 Gy dose point had a more significant apoptosis gene expression profile compared to the 0.5 Gy dose point and genes were not always expressed within 1 h but were sometimes expressed 24 h later. The bystander data clearly demonstrates initiation of the apoptotic cascade by the up-regulation of TP53, Bax, Bcl-2, initiator caspase 2 and effector caspase 6. The effector caspases 3 and 7 of the bystander samples demonstrated down-regulation in their gene expression levels at 0.05 Gy and 0.5 Gy at both time points therefore not

  7. Masculine sexual activity affects slow wave sleep in Golden hamsters.

    Science.gov (United States)

    Jiménez-Anguiano, A; Arteaga-Silva, M; Velázquez-Moctezuma, J

    2003-02-15

    The sleep pattern is modified by events occurring during wakefulness. In rats, it has been shown that male sexual behavior has a direct influence on sleeping patterns, increasing slow wave sleep (SWS) duration. On the other hand, the sexual behavior pattern of the male Golden hamster differs from the copulatory pattern of male rats. Male hamsters copulate faster and they do not display the motor inhibition observed in rats after each ejaculation. Moreover, close to exhaustion, hamsters display a behavioral pattern known as Long Intromission, which has been linked to an sexual inhibitory process. The present study was performed to determine the effects of male sexual activity on the sleep pattern in hamsters. Subjects were allowed to copulate for 30 and 60 min. In addition, the effect of locomotor activity was also assessed. The results show that male sexual behavior induced a significant increase of SWS II, with a reduction of wakefulness. No effect was observed on REM sleep. Locomotor activity produced only a slight effect on sleep. The results are discussed in terms of the similarities between the effects observed after sexual behavior on sleep in rats and hamsters, despite the substantial differences in the behavioral pattern.

  8. Pineal melatonin synthesis in Syrian hamsters: A summary

    Science.gov (United States)

    Rollag, M. D.

    1982-12-01

    During the past decade there has been ample documentation of the proposition that the pineal gland mediates photoperiodic influences upon reproductive behavior of hamsters. It is commonly hypothesized that the pineal gland expresses its activity by transformation of photoperiodic information into an hormonal output, that hormone being melatonin. If this hypothesis is correct, there must be some essential diffrence in melatonin's output when hamsters are exposed to different photoperiodic environments. The experiments summarized in this communication analyze pineal melatonin contents in Syrian hamsters maintained in a variety of photoperiodic conditions during different physiological states. The results demonstrate that adult hamsters have a daily surge in pineal melatonin content throughout their lifetime when exposed to simulated annual photoperiodic cycles. There is some fluctuation in the amount of pineal melatonin produced during different physiological states and photoperiodic environments, but these fluctuations seem small when compared to those normally found for other regulatory hormones. When hamsters are exposed to different photoperiodic regimens, the daily melatonin surge maintains a relatively constant phase relationship with respect to the onset of daily activity. There is a concomitant change in its phase relationship with respect to light-dark transitions.

  9. Social context modulates food hoarding in Syrian hamsters

    Directory of Open Access Journals (Sweden)

    Bibiana Montoya

    2016-09-01

    Full Text Available The effect of the presence of a con-specific in the temporal organization of food hoarding was studied in two varieties of Syrian hamster (Mesocricetus auratus: golden and long-haired. Four male hamsters of each variety were used. Their foraging behavior was observed during four individual and four shared trials in which animals were not competing for the same food source or territory. During individual trials, long-haired hamsters consumed food items directly from the food source, transporting and hoarding only remaining pieces. During shared trials, the long-haired variety hoarded food items before consumption, and increased the duration of hoarding trips, food handling in the storage, and cache size. Golden hamsters maintained the same temporal organization of hoarding behavior (i.e., hoarding food items before consumption throughout both individual and shared trials. However, the golden variety increased handling time at the food source and decreased the duration of hoarding trips, the latency of hoarding and storing size throughout the shared trials. In Syrian hamsters, the presence of a con-specific may signal high probability of food source depletion suggesting that social pressures over food availability might facilitate hoarding behavior. Further studies are required to evaluate cost-benefit balance of food hoarding and the role of cache pilferage in this species.

  10. Hamster and Murine Models of Severe Destructive Lyme Arthritis

    Directory of Open Access Journals (Sweden)

    Erik Munson

    2012-01-01

    Full Text Available Arthritis is a frequent complication of infection in humans with Borrelia burgdorferi. Weeks to months following the onset of Lyme borreliosis, a histopathological reaction characteristic of synovitis including bone, joint, muscle, or tendon pain may occur. A subpopulation of patients may progress to a chronic, debilitating arthritis months to years after infection which has been classified as severe destructive Lyme arthritis. This arthritis involves focal bone erosion and destruction of articular cartilage. Hamsters and mice are animal models that have been utilized to study articular manifestations of Lyme borreliosis. Infection of immunocompetent LSH hamsters or C3H mice results in a transient synovitis. However, severe destructive Lyme arthritis can be induced by infecting irradiated hamsters or mice and immunocompetent Borrelia-vaccinated hamsters, mice, and interferon-gamma- (IFN-γ- deficient mice with viable B. burgdorferi. The hamster model of severe destructive Lyme arthritis facilitates easy assessment of Lyme borreliosis vaccine preparations for deleterious effects while murine models of severe destructive Lyme arthritis allow for investigation of mechanisms of immunopathology.

  11. Circadian regulation of cortisol release in behaviorally split golden hamsters.

    Science.gov (United States)

    Lilley, Travis R; Wotus, Cheryl; Taylor, Daniel; Lee, Jennifer M; de la Iglesia, Horacio O

    2012-02-01

    The master circadian clock located within the hypothalamic suprachiasmatic nucleus (SCN) is necessary for the circadian rhythm of glucocorticoid (GC) release. The pathways by which the SCN sustains rhythmic GC release remain unclear. We studied the circadian regulation of cortisol release in the behaviorally split golden hamster, in which the single bout of circadian locomotor activity splits into two bouts approximately 12 h apart after exposing the animals to constant light conditions. We show that unsplit control hamsters present a single peak of cortisol release that is concomitant with a single peak of ACTH release. In contrast, split hamsters show two peaks of cortisol release that are approximately 12 h appart and are appropriately phased to each locomotor activity bout but surprisingly do not rely on rhythmic release of ACTH. Our results are consistent with a model in which the circadian pacemaker within the SCN regulates the circadian release of GC via input to the hypothalamo-pituitary-adrenal axis and via a second regulatory pathway, which likely involves sympathetic innervation of the adrenal and can operate even in the absence of ACTH circadian rhythmic release. Furthermore, we show that although the overall 24-h cortisol output in split hamsters is lower than in unsplit controls, split hamsters release constant low levels of ACTH. This result suggests that the timing, rather than the absolute amount, of cortisol release is more critical for the induction of negative feedback effects that regulate the hypothalamo-pituitary-adrenal axis.

  12. 9 CFR 3.36 - Primary enclosures used to transport live guinea pigs and hamsters.

    Science.gov (United States)

    2010-01-01

    ... live guinea pigs and hamsters. 3.36 Section 3.36 Animals and Animal Products ANIMAL AND PLANT HEALTH..., Care, Treatment, and Transportation of Guinea Pigs and Hamsters Transportation Standards § 3.36 Primary enclosures used to transport live guinea pigs and hamsters. No person subject to the Animal...

  13. A Syrian golden hamster model recapitulating ebola hemorrhagic fever.

    Science.gov (United States)

    Ebihara, Hideki; Zivcec, Marko; Gardner, Donald; Falzarano, Darryl; LaCasse, Rachel; Rosenke, Rebecca; Long, Dan; Haddock, Elaine; Fischer, Elizabeth; Kawaoka, Yoshihiro; Feldmann, Heinz

    2013-01-15

    Ebola hemorrhagic fever (EHF) is a severe viral infection for which no effective treatment or vaccine is currently available. While the nonhuman primate (NHP) model is used for final evaluation of experimental vaccines and therapeutic efficacy, rodent models have been widely used in ebolavirus research because of their convenience. However, the validity of rodent models has been questioned given their low predictive value for efficacy testing of vaccines and therapeutics, a result of the inconsistent manifestation of coagulopathy seen in EHF. Here, we describe a lethal Syrian hamster model of EHF using mouse-adapted Ebola virus. Infected hamsters displayed most clinical hallmarks of EHF, including severe coagulopathy and uncontrolled host immune responses. Thus, the hamster seems to be superior to the existing rodent models, offering a better tool for understanding the critical processes in pathogenesis and providing a new model for evaluating prophylactic and postexposure interventions prior to testing in NHPs.

  14. Homeostatic regulation of sleep in arrhythmic Siberian hamsters.

    Science.gov (United States)

    Larkin, Jennie E; Yokogawa, Tohei; Heller, H Craig; Franken, Paul; Ruby, Norman F

    2004-07-01

    Sleep is regulated by independent yet interacting circadian and homeostatic processes. The present study used a novel approach to study sleep homeostasis in the absence of circadian influences by exposing Siberian hamsters to a simple phase delay of the photocycle to make them arrhythmic. Because these hamsters lacked any circadian organization, their sleep homeostasis could be studied in the absence of circadian interactions. Control animals retained circadian rhythmicity after the phase shift and re-entrained to the phase-shifted photocycle. These animals displayed robust daily sleep-wake rhythms with consolidated sleep during the light phase beginning about 1 h after light onset. This marked sleep-wake pattern was circadian in that it persisted in constant darkness. The distribution of sleep in the arrhythmic hamsters over 24 h was similar to that in the light phase of rhythmic animals. Therefore, daily sleep amounts were higher in arrhythmic animals compared with rhythmic ones. During 2- and 6-h sleep deprivations (SD), it was more difficult to keep arrhythmic hamsters awake than it was for rhythmic hamsters. Because the arrhythmic animals obtained more non-rapid eye movement sleep (NREMS) during the SD, they showed a diminished compensatory response in NREMS EEG slow-wave activity during recovery sleep. When amounts of sleep during the SD were taken into account, there were no differences in sleep homeostasis between experimental and control hamsters. Thus loss of circadian control did not alter the homeostatic response to SD. This supports the view that circadian and homeostatic influences on sleep regulation are independent processes.

  15. Susceptibility of hamsters to Clostridium difficile isolates of differing toxinotype.

    Directory of Open Access Journals (Sweden)

    Anthony M Buckley

    Full Text Available Clostridium difficile is the most commonly associated cause of antibiotic associated disease (AAD, which caused ∼21,000 cases of AAD in 2011 in the U.K. alone. The golden Syrian hamster model of CDI is an acute model displaying many of the clinical features of C. difficile disease. Using this model we characterised three clinical strains of C. difficile, all differing in toxinotype; CD1342 (PaLoc negative, M68 (toxinotype VIII & BI-7 (toxinotype III. The naturally occurring non-toxic strain colonised all hamsters within 1-day post challenge (d.p.c. with high-levels of spores being shed in the faeces of animals that appeared well throughout the entire experiment. However, some changes including increased neutrophil influx and unclotted red blood cells were observed at early time points despite the fact that the known C. difficile toxins (TcdA, TcdB and CDT are absent from the genome. In contrast, hamsters challenged with strain M68 resulted in a 45% mortality rate, with those that survived challenge remaining highly colonised. It is currently unclear why some hamsters survive infection, as bacterial & toxin levels and histology scores were similar to those culled at a similar time-point. Hamsters challenged with strain BI-7 resulted in a rapid fatal infection in 100% of the hamsters approximately 26 hr post challenge. Severe caecal pathology, including transmural neutrophil infiltrates and extensive submucosal damage correlated with high levels of toxin measured in gut filtrates ex vivo. These data describes the infection kinetics and disease outcomes of 3 clinical C. difficile isolates differing in toxin carriage and provides additional insights to the role of each toxin in disease progression.

  16. Electronic Cigarettes and Indoor Air Quality: A Simple Approach to Modeling Potential Bystander Exposures to Nicotine

    Directory of Open Access Journals (Sweden)

    Stéphane Colard

    2014-12-01

    Full Text Available There has been rapid growth in the use of electronic cigarettes (“vaping” in Europe, North America and elsewhere. With such increased prevalence, there is currently a debate on whether the aerosol exhaled following the use of e-cigarettes has implications for the quality of air breathed by bystanders. Conducting chemical analysis of the indoor environment can be costly and resource intensive, limiting the number of studies which can be conducted. However, this can be modelled reasonably accurately based on empirical emissions data and using some basic assumptions. Here, we present a simplified model, based on physical principles, which considers aerosol propagation, dilution and extraction to determine the potential contribution of a single puff from an e-cigarette to indoor air. From this, it was then possible to simulate the cumulative effect of vaping over time. The model was applied to a virtual, but plausible, scenario considering an e-cigarette user and a non-user working in the same office space. The model was also used to reproduce published experimental studies and showed good agreement with the published values of indoor air nicotine concentration. With some additional refinements, such an approach may be a cost-effective and rapid way of assessing the potential exposure of bystanders to exhaled e-cigarette aerosol constituents.

  17. Electronic cigarettes and indoor air quality: a simple approach to modeling potential bystander exposures to nicotine.

    Science.gov (United States)

    Colard, Stéphane; O'Connell, Grant; Verron, Thomas; Cahours, Xavier; Pritchard, John D

    2014-12-24

    There has been rapid growth in the use of electronic cigarettes ("vaping") in Europe, North America and elsewhere. With such increased prevalence, there is currently a debate on whether the aerosol exhaled following the use of e-cigarettes has implications for the quality of air breathed by bystanders. Conducting chemical analysis of the indoor environment can be costly and resource intensive, limiting the number of studies which can be conducted. However, this can be modelled reasonably accurately based on empirical emissions data and using some basic assumptions. Here, we present a simplified model, based on physical principles, which considers aerosol propagation, dilution and extraction to determine the potential contribution of a single puff from an e-cigarette to indoor air. From this, it was then possible to simulate the cumulative effect of vaping over time. The model was applied to a virtual, but plausible, scenario considering an e-cigarette user and a non-user working in the same office space. The model was also used to reproduce published experimental studies and showed good agreement with the published values of indoor air nicotine concentration. With some additional refinements, such an approach may be a cost-effective and rapid way of assessing the potential exposure of bystanders to exhaled e-cigarette aerosol constituents.

  18. The role of gender, values, and culture in adolescent bystanders' strategies.

    Science.gov (United States)

    Tamm, Anni; Tulviste, Tiia

    2015-02-01

    We examined the relationship between adolescent bystanders' strategies for intervening in the bullying-like situation and their gender, values, and cultural origin. The sample consisted of 682 Estonian and Russian-Estonian adolescents (M age = 13.02 years). They were shown a video of a bullying-like situation with a non-intervening adult bystander and asked to describe what they would do if they, instead of the adult, witnessed that situation. Only 10% said that they would not intervene. Girls were more likely than boys to suggest multiple actions. Adolescents who valued conformity were less likely to propose using physical aggression. Doing nothing was less likely suggested by those who placed more importance on conformity and less on power. Estonian adolescents were more likely than their Russian-Estonian peers to suggest finding out what is going on, and less likely to say that they would do nothing. The findings suggest that although most adolescents express willingness to help the victim, they might not actually know how to intervene.

  19. Ombud’s Corner: Bystanders, you can have a role too

    CERN Multimedia

    Sudeshna Datta-Cockerill

    2015-01-01

    If you find yourself repeatedly witnessing a situation of inter personal conflict or tension between other colleagues, you have a choice: you can either turn a blind eye to it or you can try to help. In the latter case, you may wish to get another perspective or some guidance before taking steps.   Stefan, Paul and Lucas work together on a challenging project. Over time, Lucas has started to notice Paul’s verbally aggressive behaviour towards Stefan: he frequently criticises him in public, cuts him short at meetings when he is trying to make his point and is known to make derogatory remarks about him behind his back. Stefan does not seem to react but the tension between them is evident and Lucas feels increasingly uncomfortable in their company. It is never easy to know whether or not to intervene in these delicate situations, and the ‘bystander effect’ - where people do nothing - tends to prevail in most workplace cultures. Bystanders hesitate to act because th...

  20. The Emergence of New Paradigms in Student-University Relations: From In Loco Parentis to Bystander to Facilitator.

    Science.gov (United States)

    Bickel, Robert D.; Lake, Peter F.

    1997-01-01

    University liability is in transition; its role changing from a parental/custodial "in loco parentis" model (and then a bystander role) to a new model of facilitator. The university enjoys a position of authority and respect, while exercising control more subtly than in the mid-1990s. At the same time, universities may be unable to claim the same…

  1. Cell damage from radiation-induced bystander effects for different cell densities simulated by a mathematical model via cellular automata

    Energy Technology Data Exchange (ETDEWEB)

    Meireles, Sincler P. de; Santos, Adriano M.; Grynberg, Suely Epsztein, E-mail: spm@cdtn.b, E-mail: amsantos@cdtn.b, E-mail: seg@cdtn.b [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil); Nunes, Maria Eugenia S., E-mail: mariaeugenia@iceb.ufop.b [Universidade Federal de Ouro Preto (UFOP), MG (Brazil)

    2011-07-01

    During recent years, there has been a shift from an approach focused entirely on DNA as the main target of ionizing radiation to a vision that considers complex signaling pathways in cells and among cells within tissues. Several newly recognized responses were classified as the so-called non-target responses in which the biological effects are not directly related to the amount of energy deposited in the DNA of cells that were traversed by radiation. In 1992 the bystander effect was described referring to a series of responses such as death, chromosomal instability or other abnormalities that occur in non-irradiated cells that came into contact with irradiated cells or medium from irradiated cells. In this work, we have developed a mathematical model via cellular automata, to quantify cell death induced by the bystander effect. The model is based on experiments with irradiated cells conditioned medium which suggests that irradiated cells secrete molecules in the medium that are capable of damaging other cells. The computational model consists of two-dimensional cellular automata which is able to simulate the transmission of bystander signals via extrinsic route and via Gap junctions. The model has been validated by experimental results in the literature. The time evolution of the effect and the dose-response curves were obtained in good accordance to them. Simulations were conducted for different values of bystander and irradiated cell densities with constant dose. From this work, we have obtained a relationship between cell density and effect. (author)

  2. Perceptions of pesticides exposure risks by operators, workers, residents and bystanders in Greece, Italy and the UK

    NARCIS (Netherlands)

    Remoundou, K.; Brennan, M.; Sacchettini, G.; Panzone, L.; Butler-Ellis, M.C.; Capri, E.; Charistou, A.; Chaideftou, E.; Gerritsen-Ebben, M.G.; Machera, K.; Spanoghe, P.; Glass, R.; Marchis, A.; Doanngoc, K.; Hart, A.; Frewer, L.J.

    2015-01-01

    The EU Directive on the sustainable use of pesticides (EU128/2009/EC) requires European Member States to develop training activities targeting occupational exposure to pesticides, and communication material aimed at residents and bystanders. Risk perceptions, knowledge and attitudes associated with

  3. Pseudo-postpacing interval of diastolic potential after entrainment pacing of remote bystander pathway in reentrant ventricular tachycardia.

    Science.gov (United States)

    Kaneko, Yoshiaki; Nakajima, Tadashi; Irie, Tadanobu; Igawa, Osamu; Iijima, Takafumi; Ota, Masaki; Tamura, Mio; Iizuka, Takashi; Tamura, Shuntaro; Saito, Akihiro; Kurabayashi, Masahiko

    2014-09-01

    After entrainment pacing, the postpacing interval of a diastolic potential may be misinterpreted if the distal tip of the ablation catheter captures a remote bystander pathway adjacent to the critical isthmus of a complex reentrant circuit in a structurally diseased heart. We discuss this possible pitfall of entrainment mapping of reentrant ventricular tachycardia, observed after a healed myocardial infarction.

  4. Pseudo-postpacing interval of diastolic potential after entrainment pacing of remote bystander pathway in reentrant ventricular tachycardia

    OpenAIRE

    Kaneko, Yoshiaki; Nakajima, Tadashi; Irie, Tadanobu; Igawa, Osamu; Iijima, Takafumi; Ota, Masaki; Tamura, Mio; Iizuka, Takashi; Tamura, Shuntaro; Saito, Akihiro; Kurabayashi, Masahiko

    2013-01-01

    After entrainment pacing, the postpacing interval of a diastolic potential may be misinterpreted if the distal tip of the ablation catheter captures a remote bystander pathway adjacent to the critical isthmus of a complex reentrant circuit in a structurally diseased heart. We discuss this possible pitfall of entrainment mapping of reentrant ventricular tachycardia, observed after a healed myocardial infarction.

  5. Lack of evidence for low-LET radiation induced bystander response in normal human fibroblasts and colon carcinoma cells

    Energy Technology Data Exchange (ETDEWEB)

    Sowa, Marianne B.; Goetz, Wilfried; Baulch, Janet E.; Pyles, Dinah N.; Dziegielewski, J.; Yovino, Susannah; Snyder, Andrew R.; de Toledo, S. M.; Azzam, Edouard I.; Morgan, William F.

    2010-02-01

    The conventional paradigm in radiation biology has been that DNA is the primary target for energy deposition following exposure to ionizing radiation. However, studies focusing on the non-target effects of radiation, i.e. effects occurring in cells not directly exposed to radiation, imply that the target of exposure is larger than what has traditionally been assumed and could have significant implications for radiation health risks. We have conducted an extensive study of the low-LET bystander effect including multiple cell lines and endpoints and various radiation sources and exposure scenarios. In no instance do we see evidence of a low-LET induced bystander effect. However, direct comparison for alpha particle exposure showed a statistically significant media transfer bystander effect for high-LET but not for low-LET radiation. From our results it is evident that there are many confounding factors mitigating bystander responses as reported in the literature and for the cell lines we studied that there is a LET dependence for the observed responses. Our observations reflect the inherent variability in biological systems and the difficulties in extrapolating from in vitro models to radiation risks in humans.

  6. Bystanders' Reactions to Bullying: A Cross-Cultural Analysis of Personal Correlates among Italian and Singaporean Students

    Science.gov (United States)

    Pozzoli, Tiziana; Ang, Rebecca P.; Gini, Gianluca

    2012-01-01

    This study examined the role of attitudes against bullying and perceived peer pressure for intervention in explaining defending the victim and passive bystanding behavior in bullying. Participants were 1031 school-age children from two culturally diverse settings, namely Italy and Singapore, which are similar on several dimensions (e.g., quality…

  7. Inhibitory effects of Zengshengping fractions on DMBA-induced buccal pouch carcinogenesis in hamsters

    Institute of Scientific and Technical Information of China (English)

    GUAN Xiao-bing; SUN Zheng; CHEN Xiao-xin; WU Hong-ru; ZHANG Xin-yan

    2012-01-01

    Background Zengshengping (ZSP) tablets had inhibitory effects on oral precancerous lesions by reducing the incidence of oral cancer.However,the severe liver toxicity caused by systemic administration of ZSP limits the long-term use of this anti-cancer drug.The purpose of this study was to evaluate the tumor inhibitory effects due to the topical application of extracts from ZSP,a Chinese herbal drug,on 7,12-dimethlbenz(a)anthracene (DMBA) induced oral tumors in hamsters.The study also investigated the anti-cancer mechanisms of the ZSP extracts on oral carcinogenesis.Methods DMBA (0.5%) was applied topically to the buccal pouches of Syrian golden hamsters (6-8 weeks old) three times per week for six weeks in order to induce the development of oral tumors.Different fractions of ZSP were either applied topically to the oral tumor lesions or fed orally at varying dosages to animals with oral tumors for 18 weeks.Tumor volume was measured by histopathological examination.Tumor cell proliferation was evaluated by counting BrdU labeled cells and by Western blotting for mitogen-activated protein kinase (MAPK) protein levels.The protein levels of apoptosis marker Caspase-3 and regulator Bcl-2 protein were also measured by Western blotting.Results Topical application of DMBA to the left pouch of hamsters induced oral tumor formation.Animals treated with DMBA showed a loss in body weight while animals treated with ZSP maintained normal body weights.Both the ZSP n-butanol fraction and water fraction significantly reduced tumor volume by 32.6% (P <0.01) and 22.9% (P <0.01)respectively.Topical application of ZSP also markedly decreased the BrdU-positive cell numbers in oral tumor lesions and reduced the expression level of MAPK.In addition,ZSP promoted tumor cell apoptosis by increasing Caspase-3 expression but decreasing Bcl-2 protein production.Conclusion The n-butanol and water fractions of ZSP are effective at inhibiting tumor cell proliferation and stimulating

  8. Characterization of new G protein-coupled adenine receptors in mouse and hamster.

    Science.gov (United States)

    Thimm, Dominik; Knospe, Melanie; Abdelrahman, Aliaa; Moutinho, Miguel; Alsdorf, Bernt B A; von Kügelgen, Ivar; Schiedel, Anke C; Müller, Christa E

    2013-09-01

    The nucleobase adenine has previously been reported to activate G protein-coupled receptors in rat and mouse. Adenine receptors (AdeR) thus constitute a new family of purine receptors, for which the designation "P0-receptors" has been suggested. We now describe the cloning and characterization of two new members of the AdeR family from mouse (MrgA10, termed mAde1R) and hamster (cAdeR). Both receptors were expressed in Sf9 insect cells, and radioligand binding studies were performed using [(3)H]adenine. Specific binding of the radioligand was detected in transfected, but not in untransfected cells, and K D values of 286 nM (mAde1R, B max 1.18 pmol/mg protein) and 301 nM (cAdeR, B max 17.7 pmol/mg protein), respectively, were determined. A series of adenine derivatives was investigated in competition binding assays. Minor structural modifications generally led to a reduction or loss of affinity, with one exception: 2-fluoroadenine was at least as potent as adenine itself at the cAdeR. Structure-activity relationships at all AdeR orthologs and subtypes investigated so far were similar, but not identical. For functional analyses, the cAdeR was homologously expressed in Chinese hamster ovary (CHO) cells, while the mAde1R was heterologously expressed in 1321N1 astrocytoma cells. Like the previously described AdeRs from rat (rAdeR) and mouse (mAde2R), the mAde1R (EC50 9.77 nM) and the cAdeR (EC50 51.6 nM) were coupled to inhibition of adenylate cyclase. In addition, the cAdeR from hamster expressed in CHO cells produced an increase in intracellular calcium concentrations (EC50 6.24 nM) and was found to be additionally coupled to Gq proteins.

  9. Reciprocal bystander effect between α-irradiated macrophage and hepatocyte is mediated by cAMP through a membrane signaling pathway

    Energy Technology Data Exchange (ETDEWEB)

    He, Mingyuan [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Department of Radiation Oncology, China–Japan Union Hospital of Jilin University, Changchun 130033 (China); Dong, Chen; Xie, Yuexia; Li, Jitao; Yuan, Dexiao; Bai, Yang [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, No. 2094 Xie-Tu Road, Shanghai 200032 (China)

    2014-05-15

    Highlights: • α-Irradiation induced reciprocal effects between macrophage and hepatocyte cells. • cAMP played a protective role in regulating the reverse bystander effect. • cAMP communication contributed to the reciprocal effects via membrane signaling. • p53 was required for cAMP-regulated bystander effect in the recipient cells. - Abstract: Irradiated cells can induce biological effects on vicinal non-irradiated bystander cells, meanwhile the bystander cells may rescue the irradiated cells through a feedback signal stress. To elucidate the nature of this reciprocal effect, we examined the interaction between α-irradiated human macrophage cells U937 and its bystander HL-7702 hepatocyte cells using a cell co-culture system. Results showed that after 6 h of cell co-culture, mitochondria depolarization corresponding to apoptosis was significantly induced in the HL-7702 cells, but the formation of micronuclei in the irradiated U937 cells was markedly decreased compared to that without cell co-culture treatment. This reciprocal effect was not observed when the cell membrane signaling pathway was blocked by filipin that inhibited cAMP transmission from bystander cells to irradiated cells. After treatment of cells with exogenous cAMP, forskolin (an activator of cAMP) or KH-7 (an inhibitor of cAMP), respectively, it was confirmed that cAMP communication from bystander cells to targeted cells could mitigate radiation damage in U739 cells, and this cAMP insufficiency in the bystander cells contributed to the enhancement of bystander apoptosis. Moreover, the bystander apoptosis in HL-7702 cells was aggravated by cAMP inhibition but it could not be evoked when p53 of HL-7702 cells was knocked down no matter of forskolin and KH-7 treatment. In conclusion, this study disclosed that cAMP could be released from bystander HL-7702 cells and compensated to α-irradiated U937 cells through a membrane signaling pathway and this cAMP communication played a profound role in

  10. Efficient gene targeting in golden Syrian hamsters by the CRISPR/Cas9 system.

    Directory of Open Access Journals (Sweden)

    Zhiqiang Fan

    Full Text Available The golden Syrian hamster is the model of choice or the only rodent model for studying many human diseases. However, the lack of gene targeting tools in hamsters severely limits their use in biomedical research. Here, we report the first successful application of the CRISPR/Cas9 system to efficiently conduct gene targeting in hamsters. We designed five synthetic single-guide RNAs (sgRNAs--three for targeting the coding sequences for different functional domains of the hamster STAT2 protein, one for KCNQ1, and one for PPP1R12C--and demonstrated that the CRISPR/Cas9 system is highly efficient in introducing site-specific mutations in hamster somatic cells. We then developed unique pronuclear (PN and cytoplasmic injection protocols in hamsters and produced STAT2 knockout (KO hamsters by injecting the sgRNA/Cas9, either in the form of plasmid or mRNA, targeting exon 4 of hamster STAT2. Among the produced hamsters, 14.3% and 88.9% harbored germline-transmitted STAT2 mutations from plasmid and mRNA injection, respectively. Notably, 10.4% of the animals produced from mRNA injection were biallelically targeted. This is the first success in conducting site-specific gene targeting in hamsters and can serve as the foundation for developing other genetically engineered hamster models for human disease.

  11. Cloning of a hamster anti-mouse CD79B antibody sequences and identification of a new hamster immunoglobulin lambda constant IGLC gene region.

    Science.gov (United States)

    Haggart, Ryan; Perera, Jason; Huang, Haochu

    2013-06-01

    Anti-CD79 antibodies have been effective at targeting B cell lymphoma cells and depleting B cells in animal models. In order to engineer recombinant antibodies with additional effector functions in mice, we cloned and sequenced the full-length cDNAs of the heavy and light chain of a hamster anti-mouse CD79B antibody. Although hamster antibodies represent a unique source of monoclonal antibodies against mouse, rat, and human antigens, sequence information of hamster immunoglobulins (IG) is sparse. Here, we report a new hamster (Cricetulus migratorius) IG lambda constant (IGLC) gene region that is most homologous to mouse IGLC2 and IGLC3.

  12. Experimental verification for in vitro technique confirmation of bystander effect induced by gamma radiation in CHO-K1 cell line; Verificacao experimental para confirmacao da tecnica in vitro do efeito bystander induzido por radiacao gama na linhagem celular CHO-K1

    Energy Technology Data Exchange (ETDEWEB)

    Viana, P.H.L.; Goes, A.M.; Gomes, D.A., E-mail: pedroleroybio@hotmail.com [Universidade Federal de Minas Gerais (UFMG), Belo Horizonte, MG (Brazil). Departamento Bioquimica e Imunologia. Lab. de Imunologia Celular e Molecular; Grynberg, S.E., E-mail: seg@cdtn.br [Centro de Desenvolvimento da Tecnologia Nuclear (CDTN/CNEN-MG), Belo Horizonte, MG (Brazil)

    2013-08-15

    The bystander effect refers to biological responses detected in cells not directly irradiated but influenced, somehow, by signals transmitted from neighboring irradiated cells. These biological responses include sister chromatid exchange, mutations, micronucleus formation, chromosomal aberrations, carcinogenesis, apoptosis and necrosis. Although its existence is unquestionable, the mechanisms involved on triggering the bystander effect are not yet completely elucidated. Previous studies have shown that the bystander effect depends on a large variety of parameters including the radiation dose, the dose rate, the type of radiation and type of cells or tissue. This study aims to confirm the technique previously used in the literature in human cell lines for the bystander effect verification. The results suggest that the working conditions adopted by the group show technical efficiency and enables the reproduction of the bystander effect. (author)

  13. Enhanced longevity in tau mutant Syrian hamsters, Mesocricetus auratus

    NARCIS (Netherlands)

    Oklejewicz, Malgorzata; Daan, Serge

    2002-01-01

    The single-gene mutation tau in the Syrian hamster shortens the circadian period by about 20% in the homozygous mutant and simultaneously increases the mass-specific metabolic rate by about 20%. Both effects might be expected to lead to a change in longevity. To test such expectations, the life span

  14. Development of Taenia pisiformis in golden hamster (Mesocricetus auratus

    Directory of Open Access Journals (Sweden)

    Maravilla Pablo

    2011-07-01

    Full Text Available Abstract The life cycle of Taenia pisiformis includes canines as definitive hosts and rabbits as intermediate hosts. Golden hamster (Mesocricetus auratus is a rodent that has been successfully used as experimental model of Taenia solium taeniosis. In the present study we describe the course of T. pisiformis infection in experimentally infected golden hamsters. Ten females, treated with methyl-prednisolone acetate were infected with three T. pisiformis cysticerci each one excised from one rabbit. Proglottids released in faeces and adults recovered during necropsy showed that all animals were infected. Eggs obtained from the hamsters' tapeworms, were assessed for viability using trypan blue or propidium iodide stains. Afterwards, some rabbits were inoculated with eggs, necropsy was performed after seven weeks and viable cysticerci were obtained. Our results demonstrate that the experimental model of adult Taenia pisiformis in golden hamster can replace the use of canines in order to study this parasite and to provide eggs and adult tapeworms to be used in different types of experiments.

  15. Melatonin production accompanies arousal from daily torpor in Siberian hamsters.

    Science.gov (United States)

    Larkin, Jennie E; Yellon, Steven M; Zucker, Irving

    2003-01-01

    Arousal from deep hibernation is accompanied by a transient rise of melatonin (Mel) in circulation; there are no comparable analyses of Mel concentrations in species that undergo much shallower, shorter duration episodes of daily torpor. Serum Mel concentrations were determined during arousal from both natural daily torpor and torpor induced by 2-deoxy-D-glucose (2-DG) treatment (2,500 mg/kg, intraperitoneal [IP]); blood samples were drawn from the retro-orbital sinus of anesthetized Siberian hamsters. For animals kept in darkness during torpor, Mel concentrations were highest during early arousal when thermogenesis is maximal, and they decreased as body temperature increased during arousal and returned to baseline once euthermia was reestablished. In hamsters kept in the light during the torpor bout, Mel concentrations were elevated above basal values during arousal, but the response was significantly blunted in comparison with values recorded in darkness. Increased Mel concentrations were detected in hamsters only during arousal from torpor (either natural or 2-DG induced) and were not simply a result of the drug treatment; hamsters that remained euthermic or manifested mild hypothermia after drug treatment maintained basal Mel concentrations. We propose that increased Mel production may reflect enhanced sympathetic activation associated with intense thermogenesis during arousal from torpor rather than an adjustment of the circadian rhythm of Mel secretion.

  16. Development of Taenia pisiformis in golden hamster (Mesocricetus auratus).

    Science.gov (United States)

    Toral-Bastida, Elizabeth; Garza-Rodriguez, Adriana; Jimenez-Gonzalez, Diego E; Garcia-Cortes, Ramon; Avila-Ramirez, Guillermina; Maravilla, Pablo; Flisser, Ana

    2011-07-25

    The life cycle of Taenia pisiformis includes canines as definitive hosts and rabbits as intermediate hosts. Golden hamster (Mesocricetus auratus) is a rodent that has been successfully used as experimental model of Taenia solium taeniosis. In the present study we describe the course of T. pisiformis infection in experimentally infected golden hamsters. Ten females, treated with methyl-prednisolone acetate were infected with three T. pisiformis cysticerci each one excised from one rabbit. Proglottids released in faeces and adults recovered during necropsy showed that all animals were infected. Eggs obtained from the hamsters' tapeworms, were assessed for viability using trypan blue or propidium iodide stains. Afterwards, some rabbits were inoculated with eggs, necropsy was performed after seven weeks and viable cysticerci were obtained. Our results demonstrate that the experimental model of adult Taenia pisiformis in golden hamster can replace the use of canines in order to study this parasite and to provide eggs and adult tapeworms to be used in different types of experiments.

  17. Bioavailability and disposition of solanine in rats and hamsters

    NARCIS (Netherlands)

    Groen K; Pereboom-de Fauw DPKH; Besamusca P; Beekhof PK; Speijers GJA; Derks HJGM

    1992-01-01

    The toxicokinetics of [3H]-alpha-solanine after oral (po) and intravenous (iv) administration in rats and hamsters were studied, in order to decide which is the most appropriate model in risk assessment studies. The iv dose was 54 mug/kg; the oral dose was 170 mug/kg. After iv administration, the

  18. Immunogenicity of a polyvalent HIV-1 candidate vaccine based on fourteen wild type gp120 proteins in golden hamsters

    Directory of Open Access Journals (Sweden)

    Ghorbani Masoud

    2006-10-01

    Full Text Available Abstract Background One of the major obstacles in the design of an effective vaccine against HIV-1 is the hypervariability of the HIV-1 envelope glycoprotein. Most HIV-1 vaccine candidates have utilized envelope glycoprotein from a single virus isolate, but to date, none of them elicited broadly reactive humoral immunity. Herein, we hypothesised that a cocktail of HIV-1 gp120 proteins containing multiple epitopes may increase the breadth of immune responses against HIV-1. We compared and evaluated the immunogenicity of HIV-1 vaccines containing either gp120 protein alone or in combinations of four or fourteen gp120s from different primary HIV-1 isolates in immunized hamsters. Results We amplified and characterized 14 different gp120s from primary subtype B isolates with both syncytium and non-syncytium inducing properties, and expressed the proteins in Chinese Hamster Ovary (CHO cell lines. Purified proteins were used either alone or in combinations of four or fourteen different gp120s to vaccinate golden hamsters. The polyvalent vaccine showed higher antibody titers to HIV-1 subtype B isolates MN and SF162 compared to the groups that received one or four gp120 proteins. However, the polyvalent vaccine was not able to show higher neutralizing antibody responses against HIV-1 primary isolates. Interestingly, the polyvalent vaccine group had the highest proliferative immune responses and showed a substantial proportion of cross-subtype CD4 reactivity to HIV-1 subtypes B, C, and A/E Conclusion Although the polyvalent approach achieved only a modest increase in the breadth of humoral and cellular immunity, the qualitative change in the vaccine (14 vs. 1 gp120 resulted in a quantitative improvement in vaccine-induced immunity.

  19. Seasonal aspects of sleep in the Djungarian hamster

    Directory of Open Access Journals (Sweden)

    Deboer Tom

    2003-05-01

    Full Text Available Abstract Background Changes in photoperiod and ambient temperature trigger seasonal adaptations in the physiology and behaviour of many species, including the Djungarian hamster. Exposure of the hamsters to a short photoperiod and low ambient temperature leads to a reduction of the polyphasic distribution of sleep and waking over the light and dark period. In contrast, a long photoperiod enhances the daily sleep-wake amplitude leading to a decline of slow-wave activity in NREM sleep within the light period. It is unknown whether these changes can be attributed specifically to photoperiod and/or ambient temperature, or whether endogenous components are contributing factors. The influence of endogenous factors was investigated by recording sleep in Djungarian hamsters invariably maintained at a low ambient temperature and fully adapted to a short photoperiod. The second recording was performed when they had returned to summer physiology, despite the maintenance of the 'winter' conditions. Results Clear winter-summer differences were seen in sleep distribution, while total sleep time was unchanged. A significantly higher light-dark cycle modulation in NREM sleep, REM sleep and waking was observed in hamsters in the summer physiological state compared to those in the winter state. Moreover, only in summer, REM sleep episodes were longer and waking bouts were shorter during the light period compared to the dark period. EEG power in the slow-wave range (0.75–4.0 Hz in both NREM sleep and REM sleep was higher in animals in the summer physiological state than in those in the 'winter' state. In winter SWA in NREM sleep was evenly distributed over the 24 h, while in summer it decreased during the light period and increased during the dark period. Conclusion Endogenous changes in the organism underlie the differences in sleep-wake redistribution we have observed previously in hamsters recorded in a short and long photoperiod.

  20. Diffusible Factors Secreted by Glioblastoma and Medulloblastoma Cells Induce Oxidative Stress in Bystander Neural Stem Progenitors.

    Science.gov (United States)

    Sharma, Neha; Colangelo, Nicholas W; de Toledo, Sonia M; Azzam, Edouard I

    2016-08-01

    Harmful effects that alter the homeostasis of neural stem or progenitor cells (NSPs) can affect regenerative processes in the central nervous system. We investigated the effect of soluble factors secreted by control or (137)Cs-γ-irradiated glioblastoma or medulloblastoma cells on redox-modulated endpoints in recipient human NSPs. Growth medium harvested from the nonirradiated brain tumor cells, following 24 h of growth, induced prominent oxidative stress in recipient NSPs as judged by overall increases in mitochondrial superoxide radical levels (p p21(Waf1) and p27(Kip1), and perturbations in cell cycle progression (p cells to radiation only slightly altered the induced oxidative changes in the bystander NSPs, except for medium from irradiated medulloblastoma cells that was more potent at inducing apoptosis in the NSPs than medium from nonirradiated cells (p cells is often used to support the growth of stem cells.

  1. Alpha-particle-induced bystander effects between zebrafish embryos in vivo

    Energy Technology Data Exchange (ETDEWEB)

    Yum, E.H.W.; Choi, V.W.Y.; Nikezic, D. [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Li, V.W.T.; Cheng, S.H. [Department of Biology and Chemistry, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong); Yu, K.N., E-mail: peter.yu@cityu.edu.h [Department of Physics and Materials Science, City University of Hong Kong, Tat Chee Avenue, Kowloon Tong (Hong Kong)

    2009-10-15

    Dechorionaed embryos of the zebrafish, Danio rerio, at 1.5 h post-fertilization (hpf) were irradiated with alpha particles from an {sup 241}Am source. Thin polyallyldiglycol carbonate (PADC) films with a thickness of 16 mum were used as support substrates for holding the embryos and recorded alpha-particle hit positions, and thus enabled calculation of the dose absorbed by the embryos. The irradiated embryos were subsequently incubated with naive (unirradiated) embryos in such a way that the irradiated and naive embryos were spatially separated but the medium was shared. Acridine orange was used to perform in vital staining to show cell deaths in the naive embryos at 24 hpf. Our results gave evidence in supporting the existence of alpha-particle-induced bystander effects between zebrafish embryos in vivo, and a general positive correlation between the cell death signals in the naive embryos and the alpha-particle dose absorbed by the irradiated embryos.

  2. The role of individual and collective moral disengagement in peer aggression and bystanding: a multilevel analysis.

    Science.gov (United States)

    Gini, Gianluca; Pozzoli, Tiziana; Bussey, Kay

    2015-04-01

    This study investigates the relationships between individual and collective moral disengagement and aggression-related behaviors (peer aggression, defending, and passive bystanding) among 918 adolescents (55.8% boys; M age = 14.1 years, SD = 1.1). Hierarchical linear modeling showed that, at the individual level, aggressive behavior was significantly explained by both individual moral disengagement and student perceived collective moral disengagement, which was also positively associated with defending. Student perceived collective moral disengagement moderated the link between individual moral disengagement and peer aggression. At the class level, classroom collective moral disengagement explained between-class variability in all the three aggression-related behaviors. These results extend previous research by demonstrating the role of collective moral disengagement at the individual and the class levels and have potential implications for interventions.

  3. Characterisation of a bystander effect induced in human tissue explant cultures by low LET radiation

    Energy Technology Data Exchange (ETDEWEB)

    Motersill, C.; O' Malley, K.; Seymour, C.B

    2002-07-01

    The existence of a bystander effect following both alpha and gamma irradiation of many cell lines is not now in dispute. The significance of this effect for cancer risk assessment and radiotherapy treatment planning requires demonstration of its relevance in vivo. The problem in demonstrating the existence of the effect in vivo is that other systemic effects may mask or confound the effect being investigated and it is practically impossible to attribute an effect in a particular cell to a signal produced in another irradiated cell. To approach this problem, an assay has been developed where fragments of human tissue can be irradiated ex vivo and the media harvested and added to unirradiated, clonogenic cells which have a well characterised and stable response to the bystander signal. The variation in the production of a signal from patient to patient can thus be assessed. The results of a study using tissue from over 100 patients attending Beaumont and St Vincent's Hospitals in Dublin for investigation of urological disorders including follow-up after treatment for transitional cell carcinoma (TCC) and resection of suspect prostatic lesions, are now available. Blood samples from the prostate group were also obtained. The results show that there is variation in the effect of the signal produced by irradiated tissue from different patients. This holds for bladder, prostate and blood. Gender, smoking status and the existence of a malignancy influence the expression of the signal by normal tissue. Male gender, smoking and a pre-existing malignancy all reduce the amount or effect of the signal produced into medium when the tissue is exposed. The effects of exposure to medium containing the signal are transmitted to distant progeny of the exposed cell population. The results may be important not only for understanding radiation risk mechanisms for protection but also for radiotherapy treatment planning where they may open new avenues for development of drugs for

  4. Cancer suicide gene therapy with TK.007: superior killing efficiency and bystander effect.

    Science.gov (United States)

    Preuss, Ellen; Muik, Alexander; Weber, Kristoffer; Otte, Jürgen; von Laer, Dorothee; Fehse, Boris

    2011-11-01

    Suicide gene therapy is a promising concept in oncology. We have recently introduced a novel suicide gene, TK.007, which was shown to excel established herpes simplex virus thymidine kinase (HSVtk) variants when used for donor-lymphocyte modification in adoptive immunotherapy models. Here, the potential of TK.007 in killing cancer cells was studied. Initially, we transduced tumour cell lines derived from different neoplasias (glioblastoma, melanoma, lung cancer, colon cancer) with lentiviral LeGO vectors encoding TK.007 or the splice-corrected (sc)HSVtk together with an eGFP/Neo-marker. Based on direct in vitro comparison, we found that TK.007 facilitates more efficient tumour cell killing at significantly lower ganciclovir doses in all tumour cell lines tested. Also, using different readout systems, we found a significantly stronger bystander effect of TK.007 as compared to scHSVtk. Importantly, in vitro data were confirmed in vivo using a subcutaneous G62 glioblastoma model in NOD/SCID mice. In mice transplanted with scHSVtk-positive tumours, treatment with low (10 mg/kg) or standard (50 mg/kg) ganciclovir doses resulted only in short-term growth inhibition or transient tumour remission, respectively. In striking contrast, in the TK.007 group, all animals achieved continuous complete remission after both standard and low-dose ganciclovir. Finally, a substantial bystander effect for TK.007 was also confirmed with the G62 model in vivo, where significantly prolonged survival for mice bearing tumours containing only 10% or 50% TK.007-expressing cells was observed. In summary, our data indicate strongly improved anti-tumour activity of TK.007 as compared to conventional HSVtk. We therefore suppose that TK.007 is an excellent candidate for cancer suicide gene therapy.

  5. The crosstalk between α-irradiated Beas-2B cells and its bystander U937 cells through MAPK and NF-κB signaling pathways

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiamei; Yuan, Dexiao; Xiao, Linlin; Tu, Wenzhi; Dong, Chen; Liu, Weili; Shao, Chunlin, E-mail: clshao@shmu.edu.cn

    2016-01-15

    Highlights: • α-irradiated Beas-2B cells induced bystander effects in macrophage U937 cells. • The neighboring macrophages enhanced the damage of α-irradiated Beas-2B cells. • MAPK and NF-κB pathways were activated in U937 cells after cell co-culture. • NF-κB and MAPK pathways participated in the bilateral bystander responses. - Abstract: Although accumulated evidence suggests that α-particle irradiation induced bystander effect may relevant to lung injury and cancer risk assessment, the exact mechanisms are not yet elucidated. In the present study, a cell co-culture system was used to investigate the interaction between α-particle irradiated human bronchial epithelial cells (Beas-2B) and its bystander macrophage U937 cells. It was found that the cell co-culture amplified the detrimental effects of α-irradiation including cell viability decrease and apoptosis promotion on both irradiated cells and bystander cells in a feedback loop which was closely relevant to the activation of MAPK and NF-κB pathways in the bystander U937 cells. When these two pathways in U937 cells were disturbed by special pharmacological inhibitors before cell co-culture, it was found that a NF-κB inhibitor of BAY 11-7082 further enhanced the proliferation inhibition and apoptosis induction in bystander U937 cells, but MAPK inhibitors of SP600125 and SB203580 protected cells from viability loss and apoptosis and U0126 presented more beneficial effect on cell protection. For α-irradiated epithelial cells, the activation of NF-κB and MAPK pathways in U937 cells participated in detrimental cellular responses since the above inhibitors could largely attenuate cell viability loss and apoptosis of irradiated cells. Our results demonstrated that there are bilateral bystander responses between irradiated lung epithelial cells and macrophages through MAPK and NF-κB signaling pathways, which accounts for the enhancement of α-irradiation induced damage.

  6. Blame Conformity: Innocent Bystanders Can Be Blamed for a Crime as a Result of Misinformation from a Young, but Not Elderly, Adult Co-Witness.

    Science.gov (United States)

    Thorley, Craig

    2015-01-01

    This study examined whether or not exposing an eyewitness to a co-witness statement that incorrectly blames an innocent bystander for a crime can increase the likelihood of the eyewitness subsequently blaming the innocent bystander for the crime. It also examined whether or not the perceived age of the co-witness influences this effect. Participant eyewitnesses first watched a video of a crime featuring a perpetrator and an innocent bystander. They then read one of six bogus co-witness statements about the crime. All were presented as having been written by a female co-witness and they differed in terms of her age (young adult or elderly) and who she blamed for the crime (the perpetrator, the innocent bystander, or nobody). One week later the participants were asked who committed the crime. When the young adult co-witness had blamed the innocent bystander just over 40% of participants subsequently did the same. Few participants (less than 8%) in the other conditions subsequently blamed the innocent bystander. The elderly co-witness was also rated as less credible, less competent, and less accurate than the younger co-witness suggesting eyewitnesses were less likely to be influenced by her incorrect statement as they perceived her to be a less reliable source of information. The applied implications of these findings are discussed.

  7. Radiation-induced genomic instability and bystander effects: implications for radiation protection; Instabilite genomique et effet ''bystander'' induit par les rayonnements ionisants: implications pour la radioprotection

    Energy Technology Data Exchange (ETDEWEB)

    Little, J.B. [Harvard School of Public Health, Lab. of Radiobiology, Boston, MA (United States)

    2002-09-01

    Evidence has emerged over the past decade for the existence of two cellular phenomenons which challenge the standard paradigms for the induction of biological effects by ionizing radiation. In both cases, important genetic changes arise in cells that in themselves receive no radiation exposure. In the first, radiation induces a type of transmissible genomic instability in cells that leads to a persistent enhancement in the rate at which genetic alterations including mutations and chromosomal aberrations arise in the descendants of the original irradiated cell after many generations of replication. In the bystander effect, damage signals are transmitted from irradiated to non-irradiated cells in the population, leading to the occurrence of biologic effects in these 'bystander' cells. In this review, our current knowledge concerning these two phenomena is described and their potential impact on the estimation of risks of low level radiation exposure discussed. (author)

  8. TELOMERASE ACTIVITY DURING 7, 12-DIMETHYLBENZ [a] ANTHRACENE-INDUCED HAMSTER BUCCAL POUCH CARCINOGENESIS

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Objective: To investigate the roles of telomerase activity (TA) in relation to hamster buccal pouch tumor progression. Methods: male hamster were treated three times weekly with 0.5% of 7, 12-dimethyl- benzanthracene (DMBA) over a 15 weeks experimental period. Hamsters were sacrificed at 3, 6, 9, 12 and 15 weeks after treatment. Telomerase activity of hamster buccal pouch tissue were measured along with the analyses of the formation of DMBA-induced hamster buccal pouch tumors. Results: DMBA-induced squamous cell carcinomas were found at the 6th week after dosing. Telomerase activity elevation began at the 3rd week and was increasing to a plateau at the 12th week. Conclusion: Our results show that telomerase activity in the target tissue may be detected at the early stage of the DMBA-induced hamster buccal pouch tumor formation and suggests that telomerase activity may be used as a biomarker for an early clinical detection of buccal pouch cancer.

  9. Heat and cold acclimation in helium-cold hypothermia in the hamster.

    Science.gov (United States)

    Musacchia, X. J.

    1972-01-01

    A study was made of the effects of acclimation of hamsters to high (34-35 C) and low (4-5 C) temperatures for periods up to 6 weeks on the induction of hypothermia in hamsters. Hypothermia was achieved by exposing hamsters to a helox mixture of 80% helium and 20% oxygen at 0 C. Hypothermic induction was most rapid (2-3 hr) in heat-acclimated hamsters and slowest (6-12 hr) in cold-acclimated hamsters. The induction period was intermediate (5-8 hr) in room temperature nonacclimated animals (controls). Survival time in hypothermia was relatable to previous temperature acclimations. The hypothesis that thermogenesis in cold-acclimated hamsters would accentuate resistance to induction of hypothermia was substantiated.

  10. Cystolithiasis in a Syrian hamster: a different outcome

    Directory of Open Access Journals (Sweden)

    D. Petrini

    2016-08-01

    Full Text Available A 14-month-old intact male Syrian hamster was admitted for lethargy and hematuria. A total body radiographic image and abdominal ultrasonography showed the presence of a vesical calculus. During cystotomy, a sterile urine sample was obtained and sent to the diagnostic laboratory along with the urolith for analysis. Urine culture was found negative for bacterial growth, and the urolith was identified as a calcium-oxalate stone. Diet supplementation with palmitoylethanolamide, glucosamine and hesperidin was adopted the day after discharge. One year follow up revealed no presence of vesical calculi. Although this is the report of a single clinical case, this outcome differs from the results reported in the literature characterized by recurrences after few months. Considering the positive outcome and the beneficial properties of palmitoylethanolamide, glucosamine, and hesperidin, these nutritional elements in Syrian hamsters, are recommended to reduce recurrence after surgical treatment of urolithiasis.

  11. Efficient and Rapid Development of Transgenic Hamster Models of TSEs Using a Radical New Technology

    Science.gov (United States)

    2007-09-01

    by TOSK Inc. to introduce the human, sheep, and other prion genes into golden Syrian hamsters and to use the new transgenic animals both to measure...Transgenic Hamster Models of TSEs Using a Radical New Technology PRINCIPAL INVESTIGATOR: Robert G. Rohwer, Ph.D. Irena Alexeeva, Ph.D...From - To) 1 SEP 2003 - 31 AUG 2007 4. TITLE AND SUBTITLE 5a. CONTRACT NUMBER Efficient and Rapid Development of Transgenic Hamster Models of

  12. Perceptions of pesticides exposure risks by operators, workers, residents and bystanders in Greece, Italy and the UK

    Energy Technology Data Exchange (ETDEWEB)

    Remoundou, K.; Brennan, M. [Food and Society Group, Centre for Rural Economy, School of Agriculture, Food and Rural Development, Newcastle University, Newcastle Upon Tyne NE19 1AA (United Kingdom); Sacchettini, G. [Opera Research Centre, Università Cattolica del Sacro Cuore di Piacenza, 29100 Piacenza (Italy); Panzone, L. [Food and Society Group, Centre for Rural Economy, School of Agriculture, Food and Rural Development, Newcastle University, Newcastle Upon Tyne NE19 1AA (United Kingdom); Butler-Ellis, M.C. [Silsoe Spray Applications Unit, NIAB, Building 42, Wrest Park, Silsoe, Bedford MK45 4HP (United Kingdom); Capri, E. [Opera Research Centre, Università Cattolica del Sacro Cuore di Piacenza, 29100 Piacenza (Italy); Charistou, A.; Chaideftou, E. [Benaki Phytopathological Institute, 8 Stefanou Delta Street, Kifissia, Athens 14561 (Greece); Gerritsen-Ebben, M.G. [TNO Innovation for Life, Utrechtseweg 48, 3704 HE Zeist (Netherlands); Machera, K. [Benaki Phytopathological Institute, 8 Stefanou Delta Street, Kifissia, Athens 14561 (Greece); Spanoghe, P. [Department of Crop Protection, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Glass, R. [Food and Environmental Research Agency, Sand Hutton, York Y0411LZ (United Kingdom); Marchis, A. [Opera Research Centre, Università Cattolica del Sacro Cuore di Piacenza, 29100 Piacenza (Italy); Doanngoc, K. [Department of Crop Protection, Ghent University, Coupure Links 653, B-9000 Ghent (Belgium); Hart, A. [Food and Environmental Research Agency, Sand Hutton, York Y0411LZ (United Kingdom); Frewer, L.J., E-mail: Lynn.Frewer@newcastle.ac.uk [Food and Society Group, Centre for Rural Economy, School of Agriculture, Food and Rural Development, Newcastle University, Newcastle Upon Tyne NE19 1AA (United Kingdom)

    2015-02-01

    The EU Directive on the sustainable use of pesticides (EU128/2009/EC) requires European Member States to develop training activities targeting occupational exposure to pesticides, and communication material aimed at residents and bystanders. Risk perceptions, knowledge and attitudes associated with passive and occupational exposure to pesticide potentially influence the extent to which different stakeholders adopt self-protective behaviour. A methodology for assessing the link between attitudes, adoption of self-protective behaviours and exposure was developed and tested. A survey was implemented in the Greece, Italy and the UK, and targeted stakeholders associated with pesticide exposure linked to orchards, greenhouse crops and arable crops respectively. The results indicated that the adoption of protective measures is low for residents and bystanders, with the exception of residents in Greece, when compared to operators and workers, who tend to follow recommended safety practices. A regression analysis was used to examine the factors affecting the probability of adopting protective measures as well the as the level of exposure in the case of operators and workers where data are available. The results indicate that the likelihood of engaging in self-protective behaviour is not significantly affected by perceptions of own health being affected by pesticides for residents and bystanders. However, operators who perceive that their heath has been negatively affected by the use of pesticides are found to be more likely to adopt self-protective behaviours. Gender and country differences, in perceptions, attitudes and self-protection are also observed. Recommendations for improved communication, in particular for vulnerable groups, are provided. - Highlights: • Perceptions of risks associated with pesticide exposure were assessed • Surveys were conducted in Greece, Italy and the UK targeting vulnerable stakeholders • Perceptions of risk were associated with

  13. Radiation-induced bystander effects: Are they good bad or both?; Les nouvelles orientations en radiobiologie et radiopathologie

    Energy Technology Data Exchange (ETDEWEB)

    Le Guen, B.; Lallemand, J. [Electricite de France (EDF), 75 - Paris (France); Averbeck, D. [Institut Curie, 75 - Paris (France); Chetioui, A. [Paris-6 Univ., 75 (France); Gardes-Albert, M. [Paris-5 Univ., 75 (France); Mothersill, C. [Mc Master Univ., Hamilton (Canada); Gourmelon, P.; Benderitter, M. [Institut de Radioprotection et de Surete Nucleaire, 92 - Clamart (France); Chevillard, S.; Martin, M. [CEA Fontenay-aux-Roses, Dir. des sciences du vivant, 92 (France); Verrelle, P. [Centre Jean-Perrin, 63 - Clermont-Ferrand (France)

    2004-07-01

    The different contributions are as follow: the current events on the cellular responses to irradiation ( part one and two); From physico-chemistry to radiobiology: new knowledge (part one and two); Radiation-induced bystander effects: are they good bad or both; recognition of the multi visceral failure in the acute irradiation syndrome; integrated approach of the tissue carcinogenesis: differential effect sane tissue-tumoral tissue; differential diagnosis of thyroid cancers by the transcriptoma analysis. (N.C.)

  14. Photoperiodic influences on ultradian rhythms of male Siberian hamsters.

    Science.gov (United States)

    Prendergast, Brian J; Zucker, Irving

    2012-01-01

    Seasonal changes in mammalian physiology and behavior are proximately controlled by the annual variation in day length. Long summer and short winter day lengths markedly alter the amplitude of endogenous circadian rhythms and may affect ultradian oscillations, but the threshold photoperiods for inducing these changes are not known. We assessed the effects of short and intermediate day lengths and changes in reproductive physiology on circadian and ultradian rhythms of locomotor activity in Siberian hamsters. Males were maintained in a long photoperiod from birth (15 h light/day; 15 L) and transferred in adulthood to 1 of 7 experimental photoperiods ranging from 14 L to 9 L. Decreases in circadian rhythm (CR) robustness, mesor and amplitude were evident in photoperiods ≤14 L, as were delays in the timing of CR acrophase and expansion of nocturnal activity duration. Nocturnal ultradian rhythms (URs) were comparably prevalent in all day lengths, but 15 L markedly inhibited the expression of light-phase URs. The period (τ'), amplitude and complexity of URs increased in day lengths ≤13 L. Among hamsters that failed to undergo gonadal regression in short day lengths (nonresponders), τ' of the dark-phase UR was longer than in photoresponsive hamsters; in 13 L the incidence and amplitude of light-phase URs were greater in hamsters that did not undergo testicular regression. Day lengths as long as 14 L were sufficient to trigger changes in the waveform of CRs without affecting UR waveform. The transition from a long- to a short-day ultradian phenotype occurred for most UR components at day lengths of 12 L-13 L, thereby establishing different thresholds for CR and UR responses to day length. At the UR-threshold photoperiod of 13 L, differences in gonadal status were largely without effect on most UR parameters.

  15. Circadian arrhythmia dysregulates emotional behaviors in aged Siberian hamsters.

    Science.gov (United States)

    Prendergast, Brian J; Onishi, Kenneth G; Patel, Priyesh N; Stevenson, Tyler J

    2014-03-15

    Emotional behaviors are influenced by the circadian timing system. Circadian disruptions are associated with depressive-like symptoms in clinical and preclinical populations. Circadian rhythm robustness declines markedly with aging and may contribute to susceptibility to emotional dysregulation in aged individuals. The present experiments used a model of chronic circadian arrhythmia generated noninvasively, via a series of circadian-disruptive light treatments, to investigate interactions between circadian desynchrony and aging on depressive- and anxiety-like behaviors, and on limbic neuroinflammatory gene expression that has been linked with emotionality. We also examined whether a social manipulation (group housing) would attenuate effects of arrhythmia on emotionality. In aged (14-18 months of age) male Siberian hamsters, circadian arrhythmia increased behavioral despair and decreased social motivation, but decreased exploratory anxiety. These effects were not evident in younger (5-9 months of age) hamsters. Social housing (3-5 hamsters/cage) abolished the effects of circadian arrhythmia on emotionality. Circadian arrhythmia alone was without effect on hippocampal or cortical interleukin-1β (IL-1β) and indoleamine 2,3-dioxygenase (Ido) mRNA expression in aged hamsters, but social housing decreased hippocampal IL-1β and Ido mRNAs. The data demonstrate that circadian disruption can negatively impact affective state, and that this effect is pronounced in older individuals. Although clear associations between circadian arrhythmia and constitutive limbic proinflammatory activity were not evident, the present data suggest that social housing markedly inhibits constitutive hippocampal IL-1β and Ido activity, which may contribute to the ameliorating effects of social housing on a number of emotional behaviors.

  16. Circadian Regulation of Cortisol Release in Behaviorally Split Golden Hamsters

    OpenAIRE

    2011-01-01

    The master circadian clock located within the hypothalamic suprachiasmatic nucleus (SCN) is necessary for the circadian rhythm of glucocorticoid (GC) release. The pathways by which the SCN sustains rhythmic GC release remain unclear. We studied the circadian regulation of cortisol release in the behaviorally split golden hamster, in which the single bout of circadian locomotor activity splits into two bouts approximately12 h apart after exposing the animals to constant light conditions. We sh...

  17. Increased frequency of spontaneous neoplastic transformation in progeny of bystander cells from cultures exposed to densely ionizing radiation.

    Directory of Open Access Journals (Sweden)

    Manuela Buonanno

    Full Text Available An increased risk of carcinogenesis caused by exposure to space radiation during prolonged space travel is a limiting factor for human space exploration. Typically, astronauts are exposed to low fluences of ionizing particles that target only a few cells in a tissue at any one time. The propagation of stressful effects from irradiated to neighboring bystander cells and their transmission to progeny cells would be of importance in estimates of the health risks of exposure to space radiation. With relevance to the risk of carcinogenesis, we investigated, in model C3H 10T½ mouse embryo fibroblasts (MEFs, modulation of the spontaneous frequency of neoplastic transformation in the progeny of bystander MEFs that had been in co-culture 10 population doublings earlier with MEFs exposed to moderate doses of densely ionizing iron ions (1 GeV/nucleon or sparsely ionizing protons (1 GeV. An increase (P<0.05 in neoplastic transformation frequency, likely mediated by intercellular communication through gap junctions, was observed in the progeny of bystander cells that had been in co-culture with cells irradiated with iron ions, but not with protons.

  18. Workplace mobbing and bystanders' helping behaviour towards victims: the role of gender, perceived responsibility and anticipated stigma by association.

    Science.gov (United States)

    Mulder, Roelie; Pouwelse, Mieneke; Lodewijkx, Hein; Bolman, Catherine

    2014-08-01

    We examined victims' perceived responsibility and bystanders' anticipated risk of being victimized themselves when others associate them with the victim (stigma by association, SBA) as possible antecedents of bystanders' helping behaviour towards a victim of workplace mobbing, and explored the effects of gender. Guided by the attribution model of social conduct (Weiner, 2006), a 2 × 2 vignette experiment was conducted. Participants were Dutch regional government employees (N = 161). Path analyses generally supported the hypotheses, but showed different results for women and men. In the strong (Vs. weak) responsibility condition, women reported less sympathy and more anger and men only more anger, which resulted in lower helping intention. Additionally, for men the results showed an unexpected direct positive effect of responsibility on helping intention. Furthermore, in the strong SBA condition, women and men reported more fear and men, unexpectedly, more anger. Consequently, helping intention decreased. The findings on gender are discussed in the context of social role theory, gender and emotion. Our findings suggest that to prevent and tackle mobbing, organizations and professionals should be aware of the attributional and emotional processes and gender differences in bystanders' helping behaviour.

  19. Radiation-induced bystander effects and adaptive responses--the Yin and Yang of low dose radiobiology?

    Energy Technology Data Exchange (ETDEWEB)

    Mothersill, Carmel [Medical Physics and Applied Radiation Sciences Unit, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)]. E-mail: mothers@mcmaster.ca; Seymour, Colin [Medical Physics and Applied Radiation Sciences Unit, McMaster University, Hamilton, Ont., L8S 4K1 (Canada)]. E-mail: seymouc@mcmaster.ca

    2004-12-02

    Our current knowledge of the mechanisms underlying the induction of bystander effects by low doses of high or low LET ionizing radiation is reviewed. The question of what actually constitutes a protective effect is discussed in the context of adaptive (often referred to as hormetic or protective) responses. Finally the review considers critically, how bystander effects may be related to observed adaptive responses or other seemingly protective effects of low doses exposures. Bystander effects induce responses at the tissue level, which are similar to generalized stress responses. Most of the work involving low LET radiation exposure discussed in the existing literature measures a death response. Since many cell populations carry damaged cells without being exposed to radiation (so-called 'background damage'), it is possible that low doses exposures cause removal of cells carrying potentially problematic lesions, prior to exposure to radiation. This mechanism could lead to the production of 'U-shaped' or hormetic dose-response curves. The level of adverse, adaptive or apparently beneficial response will be related to the background damage carried by the original cell population, the level of organization at which damage or harm are scored and the precise definition of 'harm'. This model may be important when attempting to predict the consequences of mixed exposures involving low doses of radiation and other environmental stressors.

  20. Monitoring of bystander effect of herpes simplex virus thymidine kinase/acyclovir system using fluorescence resonance energy transfer technique.

    Science.gov (United States)

    Xiong, Tao; Li, Yongjun; Ni, Fenge; Zhang, Feng

    2012-02-01

    Cytotoxic gene therapy mediated by gene transfer of the herpes simplex virus thymidine kinase (HSV-tk) gene followed by acyclovir (ACV) treatment has been reported to inhibit malignant tumor growth in a variety of studies. The magnitude of "bystander effect" is an essential factor for this anti-tumor approach in vivo. However, the mechanism by which HSV-tk/ACV brings "bystander effect" is poorly understood. In this report, the plasmid CD3 (ECFP-CRS-DsRed) and TK-GFP were transferred to the human adenoid cystic carcinoma line ACC-M cell line. The CD3-expressing cells apoptosis was monitored using fluorescence resonance energy transfer (FRET) technique. First, CD3 and TK-GFP co-expressing ACC-M cells apoptosis was monitored using FRET technique. The apoptosis was induced by ACV and initiated by caspase3. The FRET efficient was remarkably decreased and then disappeared during cellular apoptosis, which indicated that the TK-GFP expressing ACC-M cells apoptosis, induced by ACV, was via a caspase3-dependent pathway. Secondly, CD3 and TK-GFP mixed expressing ACC-M cells apoptosis, induced by ACV, were monitored using FRET technique. The apoptotic phenomena appeared in the CD3-expressing ACC-M cells. The results show that HSV-tk/ACV system killed ACC-M cells using its bystander effect. These results confirm that HSV-tk/ACV system is potential for cancer gene therapy.

  1. Developmental Changes in the ECG of a Hamster Model of Muscular Dystrophy and Heart Failure.

    Science.gov (United States)

    Hampton, Thomas G; Kale, Ajit; McCue, Scott; Bhagavan, Hemmi N; Vandongen, Case

    2012-01-01

    Aberrant autonomic signaling is being increasingly recognized as an important symptom in neuromuscular disorders. The δ-sarcoglycan-deficient BIO TO-2 hamster is recognized as a good model for studying mechanistic pathways and sequelae in muscular dystrophy and heart failure, including autonomic nervous system (ANS) dysfunction. Recent studies using the TO-2 hamster model have provided promising preclinical results demonstrating the efficacy of gene therapy to treat skeletal muscle weakness and heart failure. Methods to accelerate preclinical testing of gene therapy and new drugs for neuromuscular diseases are urgently needed. The purpose of this investigation was to demonstrate a rapid non-invasive screen for characterizing the ANS imbalance in dystrophic TO-2 hamsters. Electrocardiograms were recorded non-invasively in conscious ∼9-month old TO-2 hamsters (n = 10) and non-myopathic F1B control hamsters (n = 10). Heart rate was higher in TO-2 hamsters than controls (453 ± 12 bpm vs. 311 ± 25 bpm, P imbalance with increased sympathetic tone and decreased parasympathetic tone in dystrophic TO-2 hamsters. Similar observations in newborn hamsters indicate autonomic nervous dysfunction may occur quite early in life in neuromuscular diseases. Our findings of autonomic abnormalities in newborn hamsters with a mutation in the δ-sarcoglycan gene suggest approaches to correct modulation of the heart rate as prevention or therapy for muscular dystrophies.

  2. Experience-independent development of the hamster circadian visual system.

    Directory of Open Access Journals (Sweden)

    August Kampf-Lassin

    Full Text Available Experience-dependent functional plasticity is a hallmark of the primary visual system, but it is not known if analogous mechanisms govern development of the circadian visual system. Here we investigated molecular, anatomical, and behavioral consequences of complete monocular light deprivation during extended intervals of postnatal development in Syrian hamsters. Hamsters were raised in constant darkness and opaque contact lenses were applied shortly after eye opening and prior to the introduction of a light-dark cycle. In adulthood, previously-occluded eyes were challenged with visual stimuli. Whereas image-formation and motion-detection were markedly impaired by monocular occlusion, neither entrainment to a light-dark cycle, nor phase-resetting responses to shifts in the light-dark cycle were affected by prior monocular deprivation. Cholera toxin-b subunit fluorescent tract-tracing revealed that in monocularly-deprived hamsters the density of fibers projecting from the retina to the suprachiasmatic nucleus (SCN was comparable regardless of whether such fibers originated from occluded or exposed eyes. In addition, long-term monocular deprivation did not attenuate light-induced c-Fos expression in the SCN. Thus, in contrast to the thalamocortical projections of the primary visual system, retinohypothalamic projections terminating in the SCN develop into normal adult patterns and mediate circadian responses to light largely independent of light experience during development. The data identify a categorical difference in the requirement for light input during postnatal development between circadian and non-circadian visual systems.

  3. Effect of diethylstilbestrol on polyamine metabolism in hamster epididymis

    Institute of Scientific and Technical Information of China (English)

    Chun-HongQiu; MasatoOhe; ShigeruMatsuzaki

    2003-01-01

    Aim: To investigate the effect of diethylstilbestrol (DES), one of the most potent endocrine disruptors, on the metabolism of polyamines in hamster epididymis. Methods: Male golden hamsters of 7-week-old were kept under a light and dark cycle of 14 h and 10 h for 1 week to stimulate maximally the gonadal function. DES was injected subcutaneously at doses of 0.01mg·kg-1·day-1,0.1mg·kg-1·day-1 and 1mg·kg-1·day-1 for one week. Results:DES treatment caused a significant decrease in the weight of epididymis. The activity of epididymal ornithine decarboxylase (ODC) increased 1 day after DES treatment, kept at a high level for 4 days and then decreased to nearly normal level at day 7. The activity of spermidine/spermine N1-acetyltransferase (SSAT) also increased transiently after DES treatment. The contents of putrescine, spermidine, spermine and N1-acetylspermidine were increased 1 day 4 days after DES treatment and restored to normal at day 7. All these changes showed a marked difference between the caput and the cauda. Conclusion: The polyamine biosynthesis in the hamster epididymis can be affected by DES,a xenoestrogen. DES may probably affect polyamine metabolism in the epididymis by regulating the rate-limiting enzymes involved in the polyamine biosynthesis.

  4. Female-biased anorexia and anxiety in the Syrian hamster.

    Science.gov (United States)

    Shannonhouse, John L; Fong, Li An; Clossen, Bryan L; Hairgrove, Ross E; York, Daniel C; Walker, Benjamin B; Hercules, Gregory W; Mertesdorf, Lauren M; Patel, Margi; Morgan, Caurnel

    2014-06-22

    Anorexia and anxiety cause significant mortality and disability with female biases and frequent comorbidity after puberty, but the scarcity of suitable animal models impedes understanding of their biological underpinnings. It is reported here that in adult or weanling Syrian hamsters, relative to social housing (SH), social separation (SS) induced anorexia characterized as hypophagia, weight loss, reduced adiposity, and hypermetabolism. Following anorexia, SS increased reluctance to feed, and thigmotaxis, in anxiogenic environments. Importantly, anorexia and anxiety were induced post-puberty with female biases. SS also reduced hypothalamic corticotrophin-releasing factor mRNA and serum corticosteroid levels assessed by RT-PCR and RIA, respectively. Consistent with the view that sex differences in adrenal suppression contributed to female biases in anorexia and anxiety by disinhibiting neuroimmune activity, SS elevated hypothalamic interleukin-6 and toll-like receptor 4 mRNA levels. Although corticosteroids were highest during SH, they were within the physiological range and associated with juvenile-like growth of white adipose, bone, and skeletal muscle. These results suggest that hamsters exhibit plasticity in bioenergetic and emotional phenotypes across puberty without an increase in stress responsiveness. Thus, social separation of hamsters provides a model of sex differences in anorexia and anxiety during adulthood and their pathogeneses during adolescence.

  5. Learned magnetic compass orientation by the Siberian hamster, Phodopus sungorus

    Energy Technology Data Exchange (ETDEWEB)

    Deutschlander, Mark E.; Freake, Michael J.; Borland, Christopher; Phillips, John B.; Madden, R C.; Anderson, Larry E.; Wilson, B W.

    2003-04-01

    Magnetic orientation has been demonstrated in Siberian hamsters, Phodopus sungorus. The behavior, using a nest building assay, shows a directional preference in nest position and appears in this animal to be a learned behavior. Hamsters were housed prior to testing in rectangular cages aligned along perpendicular axes. When subsequently tested in a radially-symmetrical arena, the hamsters positioned their nests in a bimodal distribution that coincided with the magnetic direction of the long-axis of the holding cages. In addition, results are presented that illustrate some of the factors that can influence behavioral responses to the magnetic field. In particular for P. sungorus, holding conditions prior to testing and the presence of non-magnetic cues may influence the strength and expression of magnetic orientation. Failure to consider these and other factors may help to explain why previous attempts to demonstrate magnetic orientation in a number of rodent species have failed or, when positive results have been obtained, have been difficult to replicate in other laboratories.

  6. Teratogenicity and embryotoxicity of nickel carbonyl in Syrian hamsters

    Energy Technology Data Exchange (ETDEWEB)

    Sunderman, F.W. Jr.; Shen, S.K.; Reid, M.C.; Allpass, P.R.

    1980-01-01

    Nickel carbonyl was administered to groups of pregnant hamsters by inhalation on days 4, 5, 6, 7, or 8 of gestation. The dams were killed on day 15 of gestation, and the fetuses were examined for malformations. Exposure to Ni(CO)/sub 4/ on days 4 or 5 of gestation resulted in malformation in 5.5% and 5.8% of the progeny, respectively. Progeny included 9 fetuses with cystic lungs, 7 fetuses with exencephaly, 1 fetus with exencephaly plus fused rib and 1 fetus with anophthalmia plus cleft palate. Hemorrhages into serious cavities were found. In progeny of dams exposed to Ni(CO)/sub 4/ on days 6 or 7 of gestation, there was 1 fetus with fused ribs and there were 2 fetuses with hydronephrosis. In another experiment, pregnant hamsters were exposed to inhalation of Ni(CO)/sub 4/ on day 5 of gestation; these dams were permitted to deliver their litters and to nurse their pups. There was no significant difference in the average number of live pups in the Ni(CO)/sub 4/-exposed litters compared to control litters. Neonatal mortality was increased in Ni(CO)/sub 4/-exposed litters. This study demonstrates that Ni(CO)/sub 4/ is teratogenic and embryotoxic in Syrian hamsters.

  7. Experimental Models in Syrian Golden Hamster Replicate Human Acute Pancreatitis.

    Science.gov (United States)

    Wang, Yunan; Kayoumu, Abudurexiti; Lu, Guotao; Xu, Pengfei; Qiu, Xu; Chen, Liye; Qi, Rong; Huang, Shouxiong; Li, Weiqin; Wang, Yuhui; Liu, George

    2016-06-15

    The hamster has been shown to share a variety of metabolic similarities with humans. To replicate human acute pancreatitis with hamsters, we comparatively studied the efficacy of common methods, such as the peritoneal injections of caerulein, L-arginine, the retrograde infusion of sodium taurocholate, and another novel model with concomitant administration of ethanol and fatty acid. The severity of pancreatitis was evaluated by serum amylase activity, pathological scores, myeloperoxidase activity, and the expression of inflammation factors in pancreas. The results support that the severity of pathological injury is consistent with the pancreatitis induced in mice and rat using the same methods. Specifically, caerulein induced mild edematous pancreatitis accompanied by minimal lung injury, while L-arginine induced extremely severe pancreatic injury including necrosis and neutrophil infiltration. Infusion of Na-taurocholate into the pancreatic duct induced necrotizing pancreatitis in the head of pancreas and lighter inflammation in the distal region. The severity of acute pancreatitis induced by combination of ethanol and fatty acids was between the extent of caerulein and L-arginine induction, with obvious inflammatory cells infiltration. In view of the advantages in lipid metabolism features, hamster models are ideally suited for the studies of pancreatitis associated with altered metabolism in humans.

  8. Triterpenic Acids Present in Hawthorn Lower Plasma Cholesterol by Inhibiting Intestinal ACAT Activity in Hamsters

    Directory of Open Access Journals (Sweden)

    Yuguang Lin

    2011-01-01

    Full Text Available Hawthorn (Crataegus pinnatifida is an edible fruit used in traditional Chinese medicine to lower plasma lipids. This study explored lipid-lowering compounds and underlying mechanisms of action of hawthorn. Hawthorn powder extracts inhibited acylCoA:cholesterol acyltransferase (ACAT activity in Caco-2 cells. The inhibitory activity was positively associated with triterpenic acid (i.e., oleanolic acid (OA and ursolic acid (UA contents in the extracts. Cholesterol lowering effects of hawthorn and its potential additive effect in combination with plant sterol esters (PSE were further studied in hamsters. Animals were fed a semi-synthetic diet containing 0.08% (w/w cholesterol (control or the same diet supplemented with (i 0.37% hawthorn dichloromethane extract, (ii 0.24% PSE, (iii hawthorn dichloromethane extract (0.37% plus PSE (0.24% or (iv OA/UA mixture (0.01% for 4 weeks. Compared to the control diet, hawthorn, PSE, hawthorn plus PSE and OA/UA significantly lowered plasma non-HDL (VLDL + LDL cholesterol concentrations by 8%, 9%, 21% and 6% and decreased hepatic cholesterol ester content by 9%, 23%, 46% and 22%, respectively. The cholesterol lowering effects of these ingredients were conversely associated with their capacities in increasing fecal neutral sterol excretion. In conclusion, OA and UA are responsible for the cholesterol lowering effect of hawthorn by inhibiting intestinal ACAT activity. In addition, hawthorn and particularly its bioactive compounds (OA and UA enhanced the cholesterol lowering effect of plant sterols.

  9. Things Chinese.

    Science.gov (United States)

    Law, Yip Wang

    Presented in this booklet are brief descriptions of items and activities that are symbolic of Chinese culture. Some of the items and activities described include a traditional Chinese child's outfit, dolls, sandalwood fans, writing and printing materials and techniques, toys and crafts, a Chinese abacus, and eating utensils. Several recipes for…

  10. Serum amyloid-P component of the Armenian hamster: gene structure and comparison with structure and expression of the SAP gene from Syrian hamster.

    Science.gov (United States)

    Rudnick, C M; Dowton, S B

    1993-11-01

    Serum amyloid P (SAP), a phylogenetically conserved pentraxin, is an integral component of all amyloid deposits. Regulation of expression of SAP gene expression is quite different in two related hamster species. In Syrian hamsters, the resting serum levels of SAP are determined by gender, and the direction of alteration following inflammation is divergent. In Armenian hamsters, SAP is not a prominent acute-phase reactant and there is no gender dimorphism of expression. The structure and expression of the SAP gene of the Armenian hamsters was investigated by isolation of genomic clones, nucleotide sequence analysis, and RNA studies. The gene structure of Armenian hamster SAP is similar to the genes of all other pentraxins studied. While the upstream regions of the SAP genes of Syrian and Armenian hamsters are quite similar, important differences in potential enhancer sites have been recognized by comparing the corresponding sequences of SAP genes from both species. Little alteration in hepatic levels of transcripts encoding SAP or CRP, the other pentraxin, were noted following administration of lipopolysaccharide to Armenian hamsters. This relative lack of response occurred despite a marked acute phase reaction documented for serum amyloid A mRNA levels.

  11. Adenoviral delivery of pan-caspase inhibitor p35 enhances bystander killing by P450 gene-directed enzyme prodrug therapy using cyclophosphamide+

    Directory of Open Access Journals (Sweden)

    Doloff Joshua C

    2010-09-01

    Full Text Available Abstract Background Cytochrome P450-based suicide gene therapy for cancer using prodrugs such as cyclophosphamide (CPA increases anti-tumor activity, both directly and via a bystander killing mechanism. Bystander cell killing is essential for the clinical success of this treatment strategy, given the difficulty of achieving 100% efficient gene delivery in vivo using current technologies. Previous studies have shown that the pan-caspase inhibitor p35 significantly increases CPA-induced bystander killing by tumor cells that stably express P450 enzyme CYP2B6 (Schwartz et al, (2002 Cancer Res. 62: 6928-37. Methods To further develop this approach, we constructed and characterized a replication-defective adenovirus, Adeno-2B6/p35, which expresses p35 in combination with CYP2B6 and its electron transfer partner, P450 reductase. Results The expression of p35 in Adeno-2B6/p35-infected tumor cells inhibited caspase activation, delaying the death of the CYP2B6 "factory" cells that produce active CPA metabolites, and increased bystander tumor cell killing compared to that achieved in the absence of p35. Tumor cells infected with Adeno-2B6/p35 were readily killed by cisplatin and doxorubicin, indicating that p35 expression is not associated with acquisition of general drug resistance. Finally, p35 did not inhibit viral release when the replication-competent adenovirus ONYX-017 was used as a helper virus to facilitate co-replication and spread of Adeno-2B6/p35 and further increase CPA-induced bystander cell killing. Conclusions The introduction of p35 into gene therapeutic regimens constitutes an effective approach to increase bystander killing by cytochrome P450 gene therapy. This strategy may also be used to enhance other bystander cytotoxic therapies, including those involving the production of tumor cell toxic protein products.

  12. Exposures involving perturbations of the EM field have non-linear effects on radiation response and can alter the expression of radiation induced bystander effects

    Science.gov (United States)

    Mothersill, Carmel; Seymour, Colin

    2012-07-01

    Our recent data suggest there is a physical component to the bystander signal induced by radiation exposure and that alternative medicine techniques such as Reiki and acupuncture or exposures to weak EM fields alter the response of cells to direct irradiation and either altered bystander signal production or altered the response of cells receiving bystander signals. Our proposed mechanism to explain these findings is that perturbation of electromagnetic (EM) fields is central to the induction of low radiation dose responses especially non-targeted bystander effects. In this presentation we review the alternative medicine data and other data sets from our laboratory which test our hypothesis that perturbation of bio-fields will modulate radiation response in the low dose region. The other data sets include exposure to MRI, shielding using lead and or Faraday cages, the use of physical barriers to bystander signal transmission and the use of membrane channel blockers. The data taken together strongly suggest that EM field perturbation can modulate low dose response and that in fact the EM field rather than the targeted deposition of ionizing energy in the DNA may be the key determinant of dose response in a cell or organism The results also lead us to suspect that at least when chemical transmission is blocked, bystander signals can be transmitted by other means. Our recent experiments suggest light signals and volatiles are not likely. We conclude that alternative medicine and other techniques involving electromagnetic perturbations can modify the response of cells to low doses of ionizing radiation and can induce bystander effects similar to those seen in medium transfer experiments. In addition to the obvious implications for mechanistic studies of low dose effects, this could perhaps provide a novel target to exploit in space radiation protection and in optimizing therapeutic gain during radiotherapy.

  13. The presence of opioidergic pinealocytes in the pineal gland of the European hamster (Cricetus cricetus): an immunocytochemical study

    DEFF Research Database (Denmark)

    Coto-Montes, A.; Masson-Pévet, M.; Pévet, P.;

    1994-01-01

    Neurobiologi, pineal gland, leu-enkephalin, Met-enkephalin, synaptic contacts, paracrine regulation, European hamster, cricetus cricetus (rodents)......Neurobiologi, pineal gland, leu-enkephalin, Met-enkephalin, synaptic contacts, paracrine regulation, European hamster, cricetus cricetus (rodents)...

  14. Developmental Changes in the ECG of a Hamster Model of Muscular Dystrophy and Heart Failure

    Directory of Open Access Journals (Sweden)

    Thomas Gerard Hampton

    2012-05-01

    Full Text Available Aberrant autonomic signaling is being increasingly recognized as an important symptom in neuromuscular disorders. The delta-sarcoglycan-deficient BIO TO-2 hamster is recognized as a good model for studying mechanistic pathways and sequelae in muscular dystrophy and heart failure, including autonomic nervous system dysfunction. Recent studies using the TO-2 hamster model have provided promising preclinical results demonstrating the efficacy of gene therapy to treat skeletal muscle weakness and heart failure. Methods to accelerate preclinical testing of gene therapy and new drugs for neuromuscular diseases are urgently needed. The purpose of this investigation was to demonstrate a rapid non-invasive screen for characterizing the autonomic nervous system imbalance in dystrophic TO-2 hamsters. Electrocardiograms were recorded non-invasively in conscious ~9-month old TO-2 hamsters (n=10 and non-myopathic F1B control hamsters (n=10. Heart rate was higher in TO-2 hamsters than controls (453 ± 12 bpm vs. 311 ± 25 bpm, P<0.01. Time domain heart rate variability, an index of parasympathetic tone, was lower in TO-2 hamsters (12.2 ± 3.7 bpm vs. 38.2 ± 6.8, P<0.05, as was the coefficient of variance of the RR interval (2.8 ± 0.9 % vs. 16.2 ± 3.4 %, P<0.05 compared to control hamsters. Power spectral analysis demonstrated reduced high frequency and low frequency contributions, indicating autonomic imbalance with increased sympathetic tone and decreased parasympathetic tone in dystrophic TO-2 hamsters. Similar observations in newborn hamsters indicate autonomic nervous dysfunction may occur quite early in life in neuromuscular diseases. Our findings of autonomic abnormalities in newborn hamsters with a mutation in the delta-sarcoglycan gene suggest approaches to correct modulation of the heart rate as prevention or therapy for muscular dystrophies.

  15. Bystander activation of CD8+ T lymphocytes during experimental mycobacterial infection.

    Science.gov (United States)

    Gilbertson, Brad; Germano, Susie; Steele, Pauline; Turner, Steven; Fazekas de St Groth, Barbara; Cheers, Christina

    2004-12-01

    Infection of C57BL/6 mice with Mycobacterium avium leads to the activation of both CD4+ and CD8+ gamma interferon (IFN-gamma)-producing T cells, although the CD8+ cells play no role in protection against infection. Using transfer of different lines of transgenic T cells with T-cell receptors (TCRs) which recognize irrelevant antigens, we show here that transferred CD8+ T cells from two of the three lines were activated to the same degree as the host cells, suggesting that the majority of the IFN-gamma-producing CD8+ T cells of the host represented bystander activation. The third line, specific for the male HY antigen, showed no activation. Activation required the participation of the CD28 coreceptor on T cells and was unaffected by the removal of CD44(hi) (memory phenotype) T cells. The transferred CD8+ T cells proliferated in vivo, although this was not essential for IFN-gamma production. Taken together, these data are highly reminiscent of homeostatic proliferation of TCR transgenic T cells upon transfer to lymphopenic hosts, and suggest low-affinity stimulation through the TCR, possibly by self peptides. The findings are discussed in relation to homeostatic proliferation and their significance in the possible induction of autoimmune disease.

  16. Presence of viral nucleic acids in the middle ear: acute otitis media pathogen or bystander?

    Science.gov (United States)

    Chonmaitree, Tasnee; Ruohola, Aino; Hendley, J Owen

    2012-04-01

    Viruses play an important role in acute otitis media (AOM) pathogenesis, and live viruses may cause AOM in the absence of pathogenic bacteria. Detection of AOM pathogens generally relies on bacterial culture of middle ear fluid. When viral culture is used and live viruses are detected in the middle ear fluid of children with AOM, the viruses are generally accepted as AOM pathogens. Because viral culture is not sensitive and does not detect the comprehensive spectrum of respiratory viruses, polymerase chain reaction assays are commonly used to detect viral nucleic acids in the middle ear fluid. Although polymerase chain reaction assays have greatly increased the viral detection rate, new questions arise on the significance of viral nucleic acids detected in the middle ear because nucleic acids of multiple viruses are detected simultaneously, and nucleic acids of specific viruses are detected repeatedly and in a high proportion of asymptomatic children. This article first reviews the role of live viruses in AOM and presents the point-counterpoint arguments on whether viral nucleic acids in the middle ear represent an AOM pathogen or a bystander status. Although there is evidence to support both directions, helpful information for interpretation of the data and future research direction is outlined.

  17. Variability: The common factor linking low dose-induced genomic instability, adaptation and bystander effects

    Energy Technology Data Exchange (ETDEWEB)

    Schwartz, Jeffrey L. [Department of Radiation Oncology, University of Washington Medical Center, 1959 NE Pacific, Box 356069, Seattle, WA 98195-6069 (United States)]. E-mail: jschwart@u.washington.edu

    2007-03-01

    The characteristics of low dose radiation-induced genomic instability, adaptive responses, and bystander effects were compared in order to probe possible underlying mechanisms, and develop models for predicting response to in vivo low dose radiation exposures. While there are some features that are common to all three (e.g., absence of a true dose-response, the multiple endpoints affected by each), other characteristics appear to distinguish one from the other (e.g., TP53 involvement, LET response, influence of DNA repair). Each of the responses is also highly variable; not all cell and tissue models show the same response and there is much interindividual variation in response. Most of these studies have employed in vitro cell culture or tissue explant models, and understanding underlying mechanisms and the biological significance of these low dose-responses will require study of tissue-specific in vivo endpoints. The in vitro studies strongly suggest that modeling low dose radiation effects will be a complex process, and will likely require separate study of each of these low dose phenomena. Knowledge of instability responses, for example, may not aid in predicting other low dose effects in the same tissue.

  18. Acting in solidarity: Testing an extended dual pathway model of collective action by bystander group members.

    Science.gov (United States)

    Saab, Rim; Tausch, Nicole; Spears, Russell; Cheung, Wing-Yee

    2015-09-01

    We examined predictors of collective action among bystander group members in solidarity with a disadvantaged group by extending the dual pathway model of collective action, which proposes one efficacy-based and one emotion-based path to collective action (Van Zomeren, Spears, Fischer, & Leach, 2004). Based on two proposed functions of social identity performance (Klein, Spears, & Reicher, 2007), we distinguished between the efficacy of collective action at consolidating the identity of a protest movement and its efficacy at achieving social change (political efficacy). We expected identity consolidation efficacy to positively predict collective action tendencies directly and indirectly via political efficacy. We also expected collective action tendencies to be positively predicted by moral outrage and by sympathy in response to disadvantaged outgroup's suffering. These hypotheses were supported in two surveys examining intentions to protest for Palestine in Britain (Study 1), and intentions to attend the June 4th vigil in Hong Kong to commemorate the Tiananmen massacre among a sample of Hong Kong citizens (Study 2). The contributions of these findings to research on the dual pathway model of collective action and the different functions of collective action are discussed.

  19. Teens’ Self-Efficacy to Deal with Dating Violence as Victim, Perpetrator or Bystander

    Science.gov (United States)

    Van Camp, Tinneke; Hébert, Martine; Guidi, Elisa; Lavoie, Francine; Blais, Martin

    2015-01-01

    Multiple studies have demonstrated that adolescent dating violence is highly prevalent and associated with internalizing and externalizing problems. A number of prevention initiatives are being implemented in North-American high schools. Such initiatives do not only aim to raise awareness among potential victims and offenders but also among peer bystanders. Since teenagers mainly reach out to their peers when experiencing adversity, it is important to address adolescents’ efficiency to deal with witnessing dating violence or with friends disclosing dating abuse, in addition to increasing ability to deal with experienced dating violence victimization or perpetration. The aim of this study is to explore adolescents’ self-efficacy to deal with dating violence victimization and perpetration in their relationships and those of their peers. A paper-and-pencil questionnaire was completed by 259 14–18 years olds in Quebec, Canada. The data allows building insight into adolescents’ confidence to reach out for help or to help others in a situation of dating violence victimization and perpetration. We also considered the impact of gender and dating victimization history. Results suggest that dating violence prevention can build on teens’ self-efficacy to deal with dating violence and offer them tools to do so efficiently. PMID:26807554

  20. CpG oligodeoxynucleotides with crude parasite antigens reduce worm recovery in Opisthorchis viverrini infected hamsters.

    Science.gov (United States)

    Kaewraemruaen, Chamraj; Sermswan, Rasana W; Wongratanacheewin, Surasakdi

    2016-12-01

    Opisthorchis viverrini, a human liver fluke, is still an endemic parasitic infection in Thailand and nearly all countries in Southeast Asia. O. viverrini induces a chronic stage of infection in hamsters. During the first 2 weeks of infection, Th1 inducing cytokine, IL-12, increased but was down regulated in chronic infection. In this study it was found that unmethylated-CpG ODN (oligodeoxynucleotides) 1826 increased hamster mononuclear cell proliferation and stimulated IFN-γ production in vitro. The IFN-γ levels in hamster sera were significantly increased in hamsters injected with CpG ODN 1826 alone or plus crude somatic antigens (CSAg). Further investigation using the flow cytometer found that CD4(+)T cells and IFN-γ(+) CD4(+)T cells (Th1-like cells) in the hamster blood were significantly increased. The role of these cells in the protective responses in hamsters was evaluated by challenging with 25 metacercaria and observation for 3 months. The number of worms recovered was significantly reduced in the hamsters injected with CpG ODN 1826 with CSAg, but not in CpG ODN 1826 alone groups when compared to PBS control. The percent of reduction in hamsters against this parasite were 32.95% and 21.49% in the CpG ODN 1826 with CSAg and CpG ODN 1826 alone. This study indicates that CpG ODN 1826 plus parasite antigens elicit a Th1-like response that leads to the enhancement of worm reduction.

  1. The Chemistry of Cold: Mechanisms of Torpor Regulation in the Siberian Hamster.

    Science.gov (United States)

    Cubuk, Ceyda; Bank, Jonathan H H; Herwig, Annika

    2016-01-01

    Siberian hamsters use spontaneous daily torpor, a state of hypometabolism and hypothermia, to save energy during winter. Multiple neuroendocrine signals set the scene for spontaneous torpor to occur, and several brain areas have been identified as potential sites for torpor regulation. Here, we summarize the known mechanisms of a fascinating physiological state in the Siberian hamster.

  2. Diet affects resting, but not basal metabolic rate of normothermic Siberian hamsters acclimated to winter.

    Science.gov (United States)

    Gutowski, Jakub P; Wojciechowski, Michał S; Jefimow, Małgorzata

    2011-12-01

    We examined the effect of different dietary supplements on seasonal changes in body mass (m(b)), metabolic rate (MR) and nonshivering thermogenesis (NST) capacity in normothermic Siberian hamsters housed under semi-natural conditions. Once a week standard hamster food was supplemented with either sunflower and flax seeds, rich in polyunsaturated fatty acids (FA), or mealworms, rich in saturated and monounsaturated FA. We found that neither of these dietary supplements affected the hamsters' normal winter decrease in m(b) and fat content nor their basal MR or NST capacity. NST capacity of summer-acclimated hamsters was lower than that of winter-acclimated ones. The composition of total body fat reflected the fat composition of the dietary supplements. Resting MR below the lower critical temperature of the hamsters, and their total serum cholesterol concentration were lower in hamsters fed a diet supplemented with mealworms than in hamsters fed a diet supplemented with seeds. These results indicate that in mealworm-fed hamsters energy expenditure in the cold is lower than in animals eating a seed-supplemented diet, and that the degree of FA unsaturation of diet affects energetics of heterotherms, not only during torpor, but also during normothermy.

  3. On the systematic position of the Western Hamster, Cricetus cricetus canescens Nehring (Mammalia: Rodentia)

    NARCIS (Netherlands)

    Husson, A.M.

    1959-01-01

    The systematic position of the western hamster, Cricetus cricetus canescens, has been a subject of discussion and criticism ever since NEHRING (1899, pp. 1—2) described the hamster occurring in Belgium west of the Meuse as a separate variety. The present paper is a new effort to throw more light on

  4. A Comparison of Hamster Anesthetics and Their Effect on Mosquito Blood Feeding

    Science.gov (United States)

    Hamsters or mice are often anesthetized when they are used as the hosts for insect feeding experiments. An experiment was done to determine if there was a difference in mosquito blood feeding success when fed on hamsters anesthetized using two commonly used protocols. The number of blood-fed females...

  5. Virtual bystanders in a language lesson: examining the effect of social evaluation, vicarious experience, cognitive consistency and praising on students' beliefs, self-efficacy and anxiety in a virtual reality environment

    NARCIS (Netherlands)

    Qu, C.; Ling, Y.; Heynderickx, I.; Brinkman, W.-P.

    2015-01-01

    Bystanders in a real world's social setting have the ability to influence people’s beliefs and behavior. This study examines whether this effect can be recreated in a virtual environment, by exposing people to virtual bystanders in a classroom setting. Participants (n = 26) first witnessed virtual s

  6. Phylogenetic conservation of immunoglobulin heavy chains: direct comparison of hamster and mouse Cmu genes.

    Science.gov (United States)

    McGuire, K L; Duncan, W R; Tucker, P W

    1985-08-12

    We have analyzed the JH-Cmu locus of the Syrian hamster by DNA cloning and sequencing. The single Cmu gene is highly homologous to that of the mouse. The hamster equivalents of the JH and switch (S) recombination regions are arranged as in the mouse, but surprisingly are not highly conserved. Also unlike its close murine relative, the Smu regions among inbred hamster strains are not polymorphic. The complete nucleotide sequence of hamster and mouse Cmu genes have been compared to partial Cmu sequences of other species. Conservation within a portion of the 3' untranslated region may signify functional requirements for 3' end processing. Mutational frequencies within exons and introns of hamster and mouse do not support the theory that the rate of DNA transitions to transversions decreases with evolutionary distance.

  7. SNC 80, a delta-opioid agonist, elicits phase advances in hamster circadian activity rhythms.

    Science.gov (United States)

    Byku, M; Gannon, R L

    2000-05-15

    Non-photic stimuli administered to hamsters during the subjective day can cause phase advances in circadian wheel running activity. It is believed that afferent projections from the intergeniculate leaflet of the thalamus to circadian pacemaker cells within the suprachiasmatic nucleus mediate the phase shifting effects of some non-photic stimuli. In hamsters, many of the intergeniculate leaflet afferents contain enkephalin, yet the role of opioids in producing non-photic phase shifts in hamsters has not been reported. In the present study, we show that SNC 80, an agonist for the delta opioid receptor subtype, will phase advance hamster wheel running activity rhythms when administered late in the subjective day. These results indicate that opioids may be involved in modulating the circadian pacemaker in hamsters.

  8. Photoperiodic regulation of FGF21 production in the Siberian hamster.

    Science.gov (United States)

    Samms, Ricardo J; Fowler, Maxine J; Cooper, Scott; Emmerson, Paul; Coskun, Tamer; Adams, Andrew C; Kharitonenkov, Alexei; Tsintzas, Kostas; Ebling, Francis J P

    2014-06-01

    This article is part of a Special Issue "Energy Balance". FGF21 is an endocrine member of the fibroblast growth factor superfamily that has been shown to play an important role in the physiological response to nutrient deprivation. Food restriction enhances hepatic FGF21 production, which serves to engage an integrated response to energy deficit. Specifically, elevated FGF21 levels lead to reduced gluconeogenesis and increased hepatic ketogenesis. However, circulating FGF21 concentrations also paradoxically rise in states of metabolic dysfunction such as obesity. Furthermore, multiple peripheral tissues also produce FGF21 in addition to the liver, raising questions as to its endocrine and paracrine roles in the control of energy metabolism. The objectives of this study were to measure plasma FGF21 concentrations in the Siberian hamster, a rodent which undergoes a seasonal cycle of fattening and body weight gain in the long days (LD) of summer, followed by reduction of appetite and fat catabolism in the short days (SD) of winter. Groups of adult male hamsters were raised in long days, and then exposed to SD for up to 12 weeks. Chronic exposure of LD animals to SD led to a significant increase in circulating FGF21 concentrations. This elevation of circulating FGF21 was preceded by an increase in liver FGF21 protein production evident as early as 4 weeks of exposure to SD. FGF21 protein abundance was also increased significantly in interscapular brown adipose tissue, with a positive correlation between plasma levels of FGF21 and BAT protein abundance throughout the experimental period. Epididymal white adipose tissue and skeletal muscle (gastrocnemius) also produced FGF21, but levels did not change in response to a change in photoperiod. In summary, a natural programmed state of fat catabolism was associated with increased FGF21 production in the liver and BAT, consistent with the view that FGF21 has a role in adapting hamsters to the hypophagic winter state.

  9. The hamster cheek pouch model for field cancerization studies.

    Science.gov (United States)

    Monti-Hughes, Andrea; Aromando, Romina F; Pérez, Miguel A; Schwint, Amanda E; Itoiz, Maria E

    2015-02-01

    External carcinogens, such as tobacco and alcohol, induce molecular changes in large areas of oral mucosa, which increase the risk of malignant transformation. This condition, known as 'field cancerization', can be detected in biopsy specimens using histochemical techniques, even before histological alterations are identified. The efficacy of these histochemical techniques as biomarkers of early cancerization must be demonstrated in appropriate models. The hamster cheek pouch oral cancer model, universally employed in biological studies and in studies for the prevention and treatment of oral cancer, is also an excellent model of field cancerization. The carcinogen is applied in solution to the surface of the mucosa and induces alterations that recapitulate the stages of cancerization in human oral mucosa. We have demonstrated that the following can be used for the early detection of cancerized tissue: silver staining of nucleolar organizer regions; the Feulgen reaction to stain DNA followed by ploidy analysis; immunohistochemical analysis of fibroblast growth factor-2, immunohistochemical labeling of proliferating cells to demonstrate an increase of epithelial cell proliferation in the absence of inflammation; and changes in markers of angiogenesis (i.e. those indicating vascular endothelial growth factor activity, endothelial cell proliferation and vascular density). The hamster cheek pouch model of oral cancer was also proposed and validated by our group for boron neutron capture therapy studies for the treatment of oral cancer. Clinical trials of this novel treatment modality have been performed and are underway for certain tumor types and localizations. Having demonstrated the efficacy of boron neutron capture therapy to control tumors in the hamster cheek pouch oral cancer model, we adapted the model for the long-term study of field cancerized tissue. We demonstrated the inhibitory effect of boron neutron capture therapy on tumor development in field

  10. Melatonin attenuates photic disruption of circadian rhythms in Siberian hamsters.

    Science.gov (United States)

    Ruby, N F; Kang, T; Heller, H C

    1997-10-01

    Body temperature (Tb) was recorded via a biotelemetry system from 28 adult male Siberian hamsters maintained in a light-dark (LD) cycle of 16 h light/day for several months. After Tb was recorded for 3 wk, the LD cycle was phase delayed by extending the light phase by 5 h for 1 day; animals remained on a 16:8 LD cycle for the remainder of the experiment. Hamsters were injected daily with melatonin or vehicle solution for several weeks, beginning either 2 mo after (experiment 1) or on the day of (experiment 2) the phase shift; injections occurred within 30 min of dark onset. In experiment 1, 75% of animals free ran with circadian periods >24 h, beginning on the day of the phase shift, and never reentrained to the LD cycle; no hamsters unambiguously entrained to daily injections. In contrast, 78% of animals in experiment 2 entrained to melatonin injections, and 71% of those animals subsequently reentrained to the photocycle when the injection regimen ended. No vehicle-treated animals entrained to the injection schedule. Melatonin had no effect on daily mean Tb and Tb rhythm amplitude in either experiment; however, melatonin doubled the duration of a hyperthermic response that occurred after each injection. Thus melatonin can prevent loss of entrainment induced by a phase shift of the LD cycle but cannot restore entrainment to free-running animals. Failure to reentrain in the presence of two appropriately coordinated entraining agents also suggests that a phase shift of the photocycle can diminish the sensitivity of the circadian system to both photic and nonphotic input.

  11. Hamster exhibits major differences in organ-specific metabolism of the esophageal carcinogen N-nitrosodiethylamine.

    Science.gov (United States)

    Visoni, Sílvia; Lang, Matti; Ribeiro Pinto, Luis Felipe

    2008-12-15

    Nitrosamines are carcinogens that require metabolic activation by CYP enzymes in order to exert their carcinogenic effect. Species differences exist in their esophageal carcinogenic potency, with the rat being the most sensitive and the Syrian hamster a resistant species. In the latter, the liver is the main target organ. This difference does not apply to directly acting N-nitroso compounds, suggesting that tissue-specific metabolic activation is involved in hamster esophageal resistance to nitrosamines. We have previously shown that Cytochrome P450 2A3 (CYP2A3) is responsible for N-nitrosodiethylamine activation in the rat esophagus. In order to find a mechanistic explanation for the resistance of hamster esophagus for nitrosamines, we have compared the metabolism of NDEA between esophagus and liver of the hamster. Hamster esophagus is capable of activating NDEA (K(m)=1.02+/-0.44microM and V(max)=1.96+/-0.26nmol acetaldehyde/min/mg microsomal protein). However, the hamster liver showed a 40-fold higher catalytic efficiency (V(max)/K(m)) towards NDEA metabolism compared with its esophagus. Hamster esophagus expresses CYP2A8, CYP2A9 and CYP2A16, but not CYP2E1. An antibody against human CYP2A6 was able to inhibit NDEA metabolism in hamster esophageal, but not liver microsomes. Our results suggest that in the hamster esophagus, but not in the liver, most of the NDEA is metabolized by CYP2A enzymes, but with a rather poor efficiency when compared to the liver. This is in accordance with previous results showing that for the hamster, the main target organ of NDEA is the liver.

  12. Virtual bystanders in a language lesson: examining the effect of social evaluation, vicarious experience, cognitive consistency and praising on students' beliefs, self-efficacy and anxiety in a virtual reality environment.

    Science.gov (United States)

    Qu, Chao; Ling, Yun; Heynderickx, Ingrid; Brinkman, Willem-Paul

    2015-01-01

    Bystanders in a real world's social setting have the ability to influence people's beliefs and behavior. This study examines whether this effect can be recreated in a virtual environment, by exposing people to virtual bystanders in a classroom setting. Participants (n = 26) first witnessed virtual students answering questions from an English teacher, after which they were also asked to answer questions from the teacher as part of a simulated training for spoken English. During the experiment the attitudes of the other virtual students in the classroom was manipulated; they could whisper either positive or negative remarks to each other when a virtual student was talking or when a participant was talking. The results show that the expressed attitude of virtual bystanders towards the participants affected their self-efficacy, and their avoidance behavior. Furthermore, the experience of witnessing bystanders commenting negatively on the performance of other students raised the participants' heart rate when it was their turn to speak. Two-way interaction effects were also found on self-reported anxiety and self-efficacy. After witnessing bystanders' positive attitude towards peer students, participants' self-efficacy when answering questions received a boost when bystanders were also positive towards them, and a blow when bystanders reversed their attitude by being negative towards them. Still, inconsistency, instead of consistency, between the bystanders' attitudes towards virtual peers and the participants was not found to result in a larger change in the participants' beliefs. Finally the results also reveal that virtual flattering or destructive criticizing affected the participants' beliefs not only about the virtual bystanders, but also about the neutral teacher. Together these findings show that virtual bystanders in a classroom can affect people's beliefs, anxiety and behavior.

  13. Virtual bystanders in a language lesson: examining the effect of social evaluation, vicarious experience, cognitive consistency and praising on students' beliefs, self-efficacy and anxiety in a virtual reality environment.

    Directory of Open Access Journals (Sweden)

    Chao Qu

    Full Text Available Bystanders in a real world's social setting have the ability to influence people's beliefs and behavior. This study examines whether this effect can be recreated in a virtual environment, by exposing people to virtual bystanders in a classroom setting. Participants (n = 26 first witnessed virtual students answering questions from an English teacher, after which they were also asked to answer questions from the teacher as part of a simulated training for spoken English. During the experiment the attitudes of the other virtual students in the classroom was manipulated; they could whisper either positive or negative remarks to each other when a virtual student was talking or when a participant was talking. The results show that the expressed attitude of virtual bystanders towards the participants affected their self-efficacy, and their avoidance behavior. Furthermore, the experience of witnessing bystanders commenting negatively on the performance of other students raised the participants' heart rate when it was their turn to speak. Two-way interaction effects were also found on self-reported anxiety and self-efficacy. After witnessing bystanders' positive attitude towards peer students, participants' self-efficacy when answering questions received a boost when bystanders were also positive towards them, and a blow when bystanders reversed their attitude by being negative towards them. Still, inconsistency, instead of consistency, between the bystanders' attitudes towards virtual peers and the participants was not found to result in a larger change in the participants' beliefs. Finally the results also reveal that virtual flattering or destructive criticizing affected the participants' beliefs not only about the virtual bystanders, but also about the neutral teacher. Together these findings show that virtual bystanders in a classroom can affect people's beliefs, anxiety and behavior.

  14. The engineered thymidylate kinase (TMPK)/AZT enzyme-prodrug axis offers efficient bystander cell killing for suicide gene therapy of cancer.

    Science.gov (United States)

    Sato, Takeya; Neschadim, Anton; Lavie, Arnon; Yanagisawa, Teruyuki; Medin, Jeffrey A

    2013-01-01

    We previously described a novel suicide (or 'cell fate control') gene therapy enzyme/prodrug system based on an engineered variant of human thymidylate kinase (TMPK) that potentiates azidothymidine (AZT) activation. Delivery of a suicide gene sequence into tumors by lentiviral transduction embodies a cancer gene therapy that could employ bystander cell killing as a mechanism driving significant tumor regression in vivo. Here we present evidence of a significant bystander cell killing in vitro and in vivo mediated by the TMPK/AZT suicide gene axis that is reliant on the formation of functional gap-junctional intercellular communications (GJICs). Potentiation of AZT activation by the engineered TMPK expressed in the human prostate cancer cell line, PC-3, resulted in effective bystander killing of PC-3 cells lacking TMPK expression--an effect that could be blocked by the GJIC inhibitor, carbenoxolone. Although GJICs are mainly formed by connexins, a new family of GJIC molecules designated pannexins has been recently identified. PC-3 cells expressed both connexin43 (Cx43) and Pannexin1 (Panx1), but Panx1 expression predominated at the plasma membrane, whereas Cx43 expression was primarily localized to the cytosol. The contribution of bystander effects to the reduction of solid tumor xenografts established by the PC-3 cell line was evaluated in an animal model. We demonstrate the contribution of bystander cell killing to tumor regression in a xenograft model relying on the delivery of expression of the TMPK suicide gene into tumors via direct intratumoral injection of recombinant therapeutic lentivirus. Taken together, our data underscore that the TMPK/AZT enzyme-prodrug axis can be effectively utilized in suicide gene therapy of solid tumors, wherein significant tumor regression can be achieved via bystander effects mediated by GJICs.

  15. SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation

    Energy Technology Data Exchange (ETDEWEB)

    Xie, Yuexia [Institute of Radiation Medicine, Fudan University, Shanghai (China); Central Laboratory, Renji Hospital, School of Medicine, Shanghai Jiaotong University, Shanghai (China); Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen [Institute of Radiation Medicine, Fudan University, Shanghai (China); Shao, Chunlin, E-mail: clshao@shmu.edu.cn [Institute of Radiation Medicine, Fudan University, Shanghai (China)

    2015-02-15

    Highlights: • γ-Irradiation induced bystander effects between hepatoma cells and hepatocyte cells. • SirT1 played a protective role in regulating this bystander effect. • SirT1 contributed to the protective effects via elimination the accumulation of ROS. • The activity of c-Myc is critical for maintaining the protective role of SirT1. - Abstract: Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved.

  16. The engineered thymidylate kinase (TMPK/AZT enzyme-prodrug axis offers efficient bystander cell killing for suicide gene therapy of cancer.

    Directory of Open Access Journals (Sweden)

    Takeya Sato

    Full Text Available We previously described a novel suicide (or 'cell fate control' gene therapy enzyme/prodrug system based on an engineered variant of human thymidylate kinase (TMPK that potentiates azidothymidine (AZT activation. Delivery of a suicide gene sequence into tumors by lentiviral transduction embodies a cancer gene therapy that could employ bystander cell killing as a mechanism driving significant tumor regression in vivo. Here we present evidence of a significant bystander cell killing in vitro and in vivo mediated by the TMPK/AZT suicide gene axis that is reliant on the formation of functional gap-junctional intercellular communications (GJICs. Potentiation of AZT activation by the engineered TMPK expressed in the human prostate cancer cell line, PC-3, resulted in effective bystander killing of PC-3 cells lacking TMPK expression--an effect that could be blocked by the GJIC inhibitor, carbenoxolone. Although GJICs are mainly formed by connexins, a new family of GJIC molecules designated pannexins has been recently identified. PC-3 cells expressed both connexin43 (Cx43 and Pannexin1 (Panx1, but Panx1 expression predominated at the plasma membrane, whereas Cx43 expression was primarily localized to the cytosol. The contribution of bystander effects to the reduction of solid tumor xenografts established by the PC-3 cell line was evaluated in an animal model. We demonstrate the contribution of bystander cell killing to tumor regression in a xenograft model relying on the delivery of expression of the TMPK suicide gene into tumors via direct intratumoral injection of recombinant therapeutic lentivirus. Taken together, our data underscore that the TMPK/AZT enzyme-prodrug axis can be effectively utilized in suicide gene therapy of solid tumors, wherein significant tumor regression can be achieved via bystander effects mediated by GJICs.

  17. A GM-CSF and CD40L bystander vaccine is effective in a murine breast cancer model

    Directory of Open Access Journals (Sweden)

    Soliman H

    2015-12-01

    Full Text Available Hatem Soliman,1 Melanie Mediavilla-Varela,2 Scott J Antonia,3 1Department of Women's Oncology and Experimental Therapeutics, 2Department of Immunology, 3Department of Thoracic Oncology, Moffitt Cancer Center, Tampa, FL, USA Background: There is increasing interest in using cancer vaccines to treat breast cancer patients in the adjuvant setting to prevent recurrence in high risk situations or in combination with other immunomodulators in the advanced setting. Current peptide vaccines are limited by immunologic compatibility issues, and engineered autologous cellular vaccines are difficult to produce on a large scale. Using standardized bystander cell lines modified to secrete immune stimulating adjuvant substances can greatly enhance the ability to produce immunogenic cellular vaccines using unmodified autologous cells or allogeneic medical grade tumor cell lines as targets. We investigated the efficacy of a cellular vaccine using B78H1 bystander cell lines engineered to secrete granulocyte macrophage-colony stimulating factor and CD40 ligand (BCG in a murine model of breast cancer. Methods: Five-week-old female BALB/c mice were injected orthotopically in the mammary fat pad with 4T1 tumor cells. Treatment consisted of irradiated 4T1 ± BCG cells given subcutaneously every 4 days and was repeated three times per mouse when tumors became palpable. Tumors were measured two to three times per week for 25 days. The vaccine's activity was confirmed in a second experiment using Lewis lung carcinoma (LLC cells in C57BL/6 mice to exclude a model specific effect. Interferon-γ (IFN-γ and interleukin-2 (IL-2 enzyme-linked immunospots (ELISPOTS were performed on splenic lymphocytes incubated with 4T1 lysates along with immunohistochemistry for CD3 on tumor sections. Results: Tumor growth was significantly inhibited in the 4T1-BCG and LLC-BCG treatment groups when compared to 4T1 and LLC treatment groups. There were higher levels of IL-2 and IFN

  18. Characterization of Chemical Suicides in the United States and Its Adverse Impact on Responders and Bystanders

    Directory of Open Access Journals (Sweden)

    Ayana R. Anderson

    2016-11-01

    Full Text Available Introduction: A suicide trend that involves mixing household chemicals to produce hydrogen sulfide or hydrogen cyanide, commonly referred to as a detergent, hydrogen sulfide, or chemical suicide is a continuing problem in the United States (U.S.. Because there is not one database responsible for tracking chemical suicides, the actual number of incidents in the U.S. is unknown. To prevent morbidity and mortality associated with chemical suicides, it is important to characterize the incidents that have occurred in the U.S. Methods: The author analyzed data from 2011-2013 from state health departments participating in the Agency for Toxic Substances and Disease Registry’s National Toxic Substance Incidents Program (NTSIP. NTSIP is a web-based chemical incident surveillance system that tracks the public health consequences (e.g., morbidity, mortality from acute chemical releases. Reporting sources for NTSIP incidents typically include first responders, hospitals, state environmental agencies, and media outlets. To find chemical suicide incidents in NTSIP’s database, the author queried open text fields in the comment, synopsis, and contributing factors variables for potential incidents. Results: Five of the nine states participating in NTSIP reported a total of 22 chemical suicide incidents or attempted suicides during 2011-2013. These states reported a total of 43 victims: 15 suicide victims who died, seven people who attempted suicide but survived, eight responders, and four employees working at a coroner’s office; the remainder were members of the general public. None of the injured responders reported receiving HazMat technician-level training, and none had documented appropriate personal protective equipment. Conclusion: Chemical suicides produce lethal gases that can pose a threat to responders and bystanders. Describing the characteristics of these incidents can help raise awareness among responders and the public about the dangers of

  19. Rehearsing for real life: the impact of the InterACT Sexual Assault Prevention Program on self-reported likelihood of engaging in bystander interventions.

    Science.gov (United States)

    Ahrens, Courtney E; Rich, Marc D; Ullman, Jodie B

    2011-06-01

    The interACT Sexual Assault Prevention Program is an interactive, skill-building performance based on the pedagogy of Augusto Boal's Theatre of the Oppressed. A longitudinal evaluation of this program compared pretest, posttest, and 3-month follow-up data from 509 university student participants. Results suggested that the interACT performance was successful in increasing participants' beliefs about the effectiveness of bystander interventions and the self-rated likelihood that participants would engage in bystander interventions in the future. Differences in both overall ratings and rates of change were noted. Implications of these results for research and practice are discussed.

  20. Signaling factors and pathways of α-particle irradiation induced bilateral bystander responses between Beas-2B and U937 cells

    Energy Technology Data Exchange (ETDEWEB)

    Fu, Jiamei; Wang, Juan; Wang, Xiangdong; Wang, Ping; Xu, Jinping; Zhou, Cuiping; Bai, Yang; Shao, Chunlin, E-mail: clshao@shmu.edu.cn

    2016-07-15

    Highlights: • Radiation damage of Beas-2B cells was enhanced by macrophage-mediated bilateral bystander responses. • Expressions of TNF-α and IL-8 in the α-irradiated Beas-2B cells were dependent on ERK and p38 pathways. • The neighboring U937 cells further increased the generation of TNF-α and IL-8 in the α-irradiated Beas-2B cells. • NF-κB dependent upregulation of TNF-α and IL-8 was induced in the bystander U937 cells. - Abstract: Although radiation induced bystander effects (RIBE) have been investigated for decades for their potential health risk, the underlying gene regulation is still largely unclear, especially the roles of immune system and inflammatory response in RIBE. In the present study, macrophage U937 cells and epithelial Beas-2B cells were co-cultured to disclose the cascades of bystander signaling factors and intercellular communications. After α-particle irradiation, both ERK and p38 pathways were activated in Beas-2B cells and were associated with the autocrine and paracrine signaling of TNF-α and IL-8, resulting in direct damage to the irradiated cells. Similar upregulation of TNF-α and IL-8 was induced in the bystander U937 cells after co-culture with α-irradiated Beas-2B cells. This upregulation was dependent on the activation of NF-κB pathway and was responsible for the enhanced damage of α-irradiated Beas-2B cells. Interestingly, the increased expressions of TNF-α and IL-8 mRNAs in the bystander U937 cells were clearly relayed on the activated ERK and p38 pathways in the irradiated Beas-2B cells, and the upregulation of TNF-α and IL-8 mRNAs in co-cultured Beas-2B cells was also partly due to the activated NF-κB pathway in the bystander U937 cells. With the pretreatment of U0126 (MEK1/2 inhibitor), SB203580 (p38 inhibitor) or BAY 11-7082 (NF-κB inhibitor), the aggravated damage in the α-irradiated Beas-2B cells could be largely alleviated. Our results disclosed novel signaling cascades of macrophage-mediated bilateral

  1. [Immune response induced by phosphofructokinase from E. histolytica in hamsters].

    Science.gov (United States)

    Jiménez Cardoso, J M; Jiménez, E; Kumate, J

    1991-01-01

    The enzymatic activity of inorganic pyrophosphate (PPi) dependent phosphofructokinase became manifest in the supernatant obtained by centrifugation in a homogenate of E. histolytica strain HMI-IMSS at 700,000 g. Partial purification of the enzyme was achieved by column chromatography with Ultrogel AcA-34. Ten protein elution spikes were obtained: five showed enzymatic activity. Elution spikes I and II attained the highest values of specific enzymatic activity 6.45 and 6.98 U/mg of protein, respectively. Next were spikes X and III with similar values 2.55 and 2.63 U/mg of protein, and spike IV presented the lowest value of 0.86 U/mg of protein. The five spikes were used to immunize hamsters which were challenged intrahepatically, four weeks later, with 3 x 10(5) trophozoites of E. histolytica. A control group of animals not immunized underwent intrahepatic challenge with the same number of amebae. The proteins with enzymatic activity contained in elution spikes I and II conferred immunologic protection in 100% of the animals, while elution spikes X and III were protective in 50 to 63%, and spike IV gave the lowest value of 37%. It can be assumed that there is an antienzyme antibody responsible for the absence of hepatic abscesses in the immunized hamsters.

  2. Sex differences in Siberian hamster ultradian locomotor rhythms.

    Science.gov (United States)

    Prendergast, Brian J; Stevenson, Tyler J; Zucker, Irving

    2013-02-17

    Sex differences in ultradian activity rhythms (URs) and circadian rhythms (CRs) were assessed in Siberian hamsters kept in long day (LD) or short day (SD) photoperiods for 40 weeks. For both sexes URs of locomotor activity were more prevalent, greater in amplitude and more robust in SDs. The UR period was longer in females than males in both day lengths. The reproductive system underwent regression and body mass declined during the initial 10 weeks of SD treatment, and in both sexes these traits spontaneously reverted to the LD phenotype at or before 40 weeks in SD, reflecting the development of neuroendocrine refractoriness to SD patterns of melatonin secretion. Hamsters of both sexes, however, continued to display SD-like URs at the 40 weeks time point. CRs were less prevalent and the waveform less robust and lower in amplitude in SDs than LDs; the SD circadian waveform also did not revert to the long-day phenotype after 40 weeks of SD treatment. Short day lengths enhanced ultradian and diminished circadian rhythms in both sexes. Day length controls several UR characteristics via gonadal steroid and melatonin-independent mechanisms. Sex differences in ultradian timing may contribute to sex diphenisms in rhythms of sleep, food intake and exercise.

  3. Constant darkness restores entrainment to phase-delayed Siberian hamsters.

    Science.gov (United States)

    Ruby, Norman F; Joshi, Nirav; Heller, H Craig

    2002-12-01

    Over 90% of Siberian hamsters (Phodopus sungorus) fail to reentrain to a 5-h phase delay of a 16:8-h photocycle. Because constant darkness (DD) restores rhythms disrupted by constant light, we tested whether DD could also restore entrainment. DD began 0, 5, or 14 days after a 5-h phase delay, and the light-dark cycle was reinstated 14 days later. All hamsters exposed to DD on day 0 reentrained, whereas 42% reentrained irrespective of whether DD began 5 or 14 days later. For these latter two groups, tau (tau) and alpha (alpha) in DD predicted reentrainment; animals that reentrained had a mean tau and alpha of 24.1 and 8.9 h, respectively, whereas those that failed to reentrain maintained a mean tau and alpha of 25.0 and of 7.1 h, respectively. Restoration of entrainment by DD is somewhat paradoxical because it suggests that reentrainment to the photocycle was prevented by continued exposure to that same photocycle. The dichotomy of circadian responses to DD suggests "entrainment" phenotypes that are similar to those of photoperiodic responders and nonresponders.

  4. Role of cathepsins in blastocyst hatching in the golden hamster.

    Science.gov (United States)

    Sireesha, G V; Mason, R W; Hassanein, M; Tonack, S; Navarrete Santos, A; Fischer, B; Seshagiri, P B

    2008-06-01

    The mammalian embryo is encased in a glycoproteinaceous coat, the zona pellucida (ZP) during preimplantation development. Prior to implantation, the blastocyst must undergo 'hatching' or ZP escape. In hamsters, there is a thinning of the ZP followed by a focal lysis and a complete dissolution of the ZP during blastocyst hatching. Earlier studies from our laboratory have indicated a role for cysteine proteases in the hatching phenomenon. In this study, we tested the effect of specific inhibitors of the three classes of cysteine protease on blastocyst hatching. Cystatin, an endogenous cathepsin inhibitor, blocked blastocyst hatching. Similarly, Fmoc-Tyr-Ala-diazomethane, a synthetic cathepsin inhibitor, blocked hatching. Both showed dose-dependent and temporal inhibition of hatching. However, Z-Val-Ala-Asp-fluoromethylketone, a synthetic caspase inhibitor, and calpastatin, an endogenous calpain inhibitor, had no effect on hatching. The cathepsins were localized to blastocyst cells. Exogenous addition of cathepsins L, P or B to cultured 8-cell embryos caused a complete ZP dissolution. The expression of mRNA and protein of cathepsins L and P was observed in peri-hatching blastocysts. Cathepsins L and P were detected in trophectodermal projections and in the ZP of peri-hatching blastocysts. These data provide the first evidence that blastocyst-derived cathepsins are functionally involved as zonalytic factors in the hatching of blastocysts in the golden hamster.

  5. C-reactive protein (CRP) of the Syrian hamster.

    Science.gov (United States)

    Dowton, S B; Holden, S N

    1991-10-01

    Complementary and genomic clones encoding the mRNA and gene for a protein in the Syrian hamster that is highly homologous to C-reactive protein (CRP) have been isolated and studied. Coding sequence of the genomic clone is identical with that of the cDNA clone and predicts a mature protein of 206 amino acids and a 19 amino acid signal peptide. The single intron is 217 base pairs long and contains a short repetitive (GT)n motif. RNA blot analysis demonstrates that mRNA for hamster CRP is approximately 2.0 kb long, and unlike the closely related pentraxin female protein (FP), expression of this mRNA is not affected by the gender of the animal and accumulates equally in males and females during inflammation. In vivo administration of interleukin 1, interleukin 6, and tumor necrosis factor induces accumulation of hepatic CRP mRNA, and the acute-phase alterations in CRP mRNA levels arise as a result of enhanced gene transcription.

  6. Pineal-independent regulation of photo-nonresponsiveness in the Siberian hamster (Phodopus sungorus).

    Science.gov (United States)

    Prendergast, B J; Freeman, D A

    1999-02-01

    The pineal hormone melatonin influences circadian rhythms and also mediates reproductive responses to photoperiod. The authors tested whether pinealectomy influences circadian oscillators responsible for induction of nonresponsiveness to short day lengths by preventing normal short-day patterns of circadian entrainment. Adult male Siberian hamsters were pinealectomized or sham operated, maintained in either 18 h light per day (18L) or 15L for 10 weeks, and then tested for responsiveness to 10L. Because pinealectomized hamsters do not show gonadal regression in short day lengths, responsiveness was assessed by measuring phase angle of entrainment and the length of the nightly activity period following transfer to 10L. The incidence of nonresponsiveness was significantly higher in 18L hamsters than in 15L hamsters but was unaffected by pineal status. Fully 88% of 18L hamsters failed to entrain to 10L in the normal short-day manner; the duration of nightly activity remained compressed, and the phase angle of entrainment was large and negative relative to lights off. The 15L hamsters entrained normally to 10L. Exposure to constant light after 10L treatment was equally effective in inducing arrhythmicity in pinealectomized and intact hamsters. Changes in the period of morning and evening circadian oscillators subsequent to 18L treatment did not predict circadian responsiveness to short photoperiod. Long-day induction of photo-nonresponsiveness, which prevents winter responses to short day lengths, occurs independently of pineal melatonin feedback on the circadian system.

  7. Daidzin suppresses ethanol consumption by Syrian golden hamsters without blocking acetaldehyde metabolism.

    Science.gov (United States)

    Keung, W M; Lazo, O; Kunze, L; Vallee, B L

    1995-09-12

    Daidzin is a potent, selective, and reversible inhibitor of human mitochondrial aldehyde dehydrogenase (ALDH) that suppresses free-choice ethanol intake by Syrian golden hamsters. Other ALDH inhibitors, such as disulfiram (Antabuse) and calcium citrate carbimide (Temposil), have also been shown to suppress ethanol intake of laboratory animals and are thought to act by inhibiting the metabolism of acetaldehyde produced from ingested ethanol. To determine whether or not daidzin inhibits acetaldehyde metabolism in vivo, plasma acetaldehyde in daidzin-treated hamsters was measured after the administration of a test dose of ethanol. Daidzin treatment (150 mg/kg per day i.p. for 6 days) significantly suppresses (> 70%) hamster ethanol intake but does not affect overall acetaldehyde metabolism. In contrast, after administration of the same ethanol dose, plasma acetaldehyde concentration in disulfiram-treated hamsters reaches 0.9 mM, 70 times higher than that of the control. In vitro, daidzin suppresses hamster liver mitochondria-catalyzed acetaldehyde oxidation very potently with an IC50 value of 0.4 microM, which is substantially lower than the daidzin concentration (70 microM) found in the liver mitochondria of daidzin-treated hamsters. These results indicate that (i) the action of daidzin differs from that proposed for the classic, broad-acting ALDH inhibitors (e.g., disulfiram), and (ii) the daidzin-sensitive mitochondrial ALDH is not the one and only enzyme that is essential for acetaldehyde metabolism in golden hamsters.

  8. Hamster Weight Patterns Predict the Intensity and Course of Schistosoma haematobium Infection.

    Science.gov (United States)

    Le, Thien-Linh P; Boyett, Deborah M; Hurley-Novatny, Amelia; Hsieh, Michael H

    2015-10-01

    Although Syrian golden hamsters are widely used as hosts for experimental infection by Schistosoma haematobium , surprisingly little is known about the course of infection and associated intensity (as defined by measures of parasite burden). As such, we sought to define inexpensive, simple, noninvasive, and accurate methods for assessing and predicting the severity of disease in S. haematobium -infected hamsters in order to prevent premature hamster sacrifice and unexpected morbidity and mortality. Through monitoring the weight and behavior of infected hamsters, we determined that the weight-loss patterns of infected hamsters are highly correlated with commonly used measures of the severity of infection (i.e., numbers of eggs passed in the stool, worm burdens, and total egg yields). In contrast, we found no significant correlation between hamster weight-loss patterns and egg yields from liver and intestinal tissues. Our findings suggest that a more complex relationship exists among worm burden, fecundity, and egg passage in the feces than previously appreciated. Regardless, our data may be useful for workers seeking to optimize harvests of S. haematobium eggs and worms from infected hamsters for downstream applications.

  9. Changes of spontaneous parthenogenetic activation and development potential of golden hamster oocytes during the aging process.

    Science.gov (United States)

    Jiang, Han; Wang, Ce; Guan, Jiyu; Wang, Lingyan; Li, Ziyi

    2015-01-01

    The golden hamster is an excellent animal experimental model for oocyte research. The hamster oocytes are very useful in clinical examination of human spermatozoan activity. Non-fertile oocytes can lead to time-dependent processes of aging, which will affect the results of human spermatozoa examination. As a consequence there is a need to investigate the aging and anti-aging processes of golden hamster oocytes. In order to study the aging processes and parthenogenetic activation of golden hamster oocytes, in vivo oocytes, oocytes cultured with or without cumulus cells, and oocytes treated with Trichostatin A (TSA) or caffeine were collected and investigated. We found that: (1) spontaneous parthenogenetic activation, developmental potential (cleavage rate), and zona pellucida (ZP) hardening undergo age-dependent changes in in vivo, in vitro, and after TSA or caffeine treatment; (2) in vivo, oocytes became spontaneously parthenogenetic 25 h post-hCG treatment; (3) in vitro, cumulus cells did not significantly increase the parthenogenetic activation rate of cultured hamster oocytes; and (4) TSA or caffeine could delay spontaneous oocyte parthenogenetic activation and the aging processes by at least 5h, but also accelerated the hardening of the ZP. These results define the conditions for the aging and anti-aging processes in golden hamster oocytes. TSA and caffeine play roles in controlling spontaneous activation, which could facilitate the storage and use of golden hamster oocytes for studying processes relevant to human reproduction.

  10. Development of chronic and acute golden Syrian hamster infection models with Leptospira borgpetersenii serovar Hardjo.

    Science.gov (United States)

    Zuerner, R L; Alt, D P; Palmer, M V

    2012-03-01

    The golden Syrian hamster (Mesocricetus auratus) is frequently used as a model to study virulence for several Leptospira species. Onset of an acute lethal infection following inoculation with several pathogenic Leptospira species has been widely adopted for pathogenesis studies. An important exception is the outcome following inoculation of hamsters with live L. borgpetersenii serovar Hardjo, the primary cause of bovine leptospirosis and a cause of human infections. Typically, inoculation of hamsters with L. borgpetersenii serovar Hardjo fails to induce clinical signs of infection. In this study, the authors defined LD(50) and ID(50) for 2 strains of L. borgpetersenii serovar Hardjo: JB197 and 203. Both strains infected hamsters with ID(50) values of approximately 1.5 × 10(2) bacteria yet differed in tissue invasion and interaction with leukocytes, resulting in widely divergent clinical outcomes. Hamsters infected with strain 203 established renal colonization within 4 days postinfection and remained asymptomatic with chronic renal infections similar to cattle infected with serovar Hardjo. In contrast, hamsters infected with strain JB197 developed a rapidly debilitating disease typical of acute leptospirosis common in accidental hosts (eg, humans) with an LD(50) of 3.6 × 10(4) bacteria. Evidence that strain JB197 resides in both extracellular and intracellular environments during hamster infection was obtained. Development of models that result in chronic and acute forms of leptospirosis provides a platform to study L. borgpetersenii pathogenesis and to test vaccines for the prevention of leptospirosis.

  11. Application study of intracytoplasmic sperm injection for golden hamster and cattle production.

    Science.gov (United States)

    Horiuchi, Toshitaka

    2006-02-01

    This paper describes several technical improvements and our results in hamster intracytoplasmic sperm injection (ICSI), hamster round spermatid injection (ROSI) and bovine ICSI. The hamster is the mammalian species in which ICSI was first tried to produce fertilized oocytes. However, until recently, no live offspring following ICSI have ever been obtained. We reported the birth of live offspring following hamster ICSI. Improved points to success were 1) performing hamster ICSI in a dark room with a small incandescent lamp and manipulating both oocytes and fertilized eggs under microscope with a red light source and 2) injecting sperm heads without acrosomes. Under controlled illumination, the majority of the oocytes injected with acrosomeless sperm heads were fertilized normally, cleaved, and developed into morulae. Nine live offspring (19%) were born by transfer of hamster ICSI-derived embryos. Furthermore, we reported the birth of live offspring following hamster ROSI. About 70% of oocytes injected with round spermatids broken before injection were fertilized normally and about half of them developed to morulae and blastocysts. Three (5%) live young were born by transfer of hamster ROSI-derived embryos. On the other hand, in cattle, the main improvements were 1) injection of spermatozoa immobilized by scoring their tail just before injection into oocytes, and 2) additional ethanol activation 4 h after ICSI. About 70% of oocytes injected were activated 4 h after ICSI, and about 30% of them developed to blastocysts. Twenty-four live calves (39%) were born by non-surgical transfer of ICSI-derived embryos. Those results shows that, at present, live offspring are able to be obtained following hamster ICSI, ROSI and bovine ICSI, but further improvement is required due to higher production efficiency of offspring.

  12. Bioavailability and disposition of 3H-solanine in rat and hamster.

    Science.gov (United States)

    Groen, K; Pereboom-de Fauw, D P; Besamusca, P; Beekhof, P K; Speijers, G J; Derks, H J

    1993-09-01

    1. The toxicokinetics of [3H]-alpha-solanine after oral (p.o.) and intravenous (i.v.) administration in rat and hamster were studied, in order to decide which is the most appropriate model in risk assessment studies. The i.v. dose was 54 micrograms/kg; the oral dose was 170 micrograms/kg. 2. After i.v. administration, the toxicokinetics of total radioactivity in blood were comparable in rat and hamster. However, the clearance of total radioactivity from plasma was more effective in rat than in hamster. The half-lives of distribution and of the terminal phase of unchanged alpha-solanine were not different between rat and hamster, whereas the systemic and metabolic clearance were, respectively, about 1.6 and 2.7 times higher in rat than in hamster. The clearance of unchanged alpha-solanine is more effective than of total radioactivity. 3. After p.o. administration in rat and hamster, the mean bioavailability of total radioactivity is about 29 and 57%, respectively. The bioavailability of unchanged alpha-solanine is only 1.6 and 3.2%, respectively, when compared with i.v. administration. 4. T1/2el of alpha-solanine after p.o. administration was in rats a factor of four and in hamsters a factor of two shorter than after i.v. administration. A strong retention of radioactivity was seen in the hamsters after p.o. administration; only 40% of the dose was excreted within 7 days versus 90% in rat. 5. Based on these and toxicological data from literature, it was decided that the hamster is a more appropriate model in (sub)-chronic toxicity studies with alpha-solanine than the rat.

  13. Lifelong persistent infection of hamster brain by human adenovirus type 6.

    Directory of Open Access Journals (Sweden)

    Yabe,Yoshiro

    1988-02-01

    Full Text Available To establish an experimental persistent infection of the brain with human adenoviruses, adenovirus type 6 (ad 6 was inoculated intracerebrally into young adult hamsters. Hamsters appeared languid for a few days after inoculation, but recovered rapidly. By cocultivation of tissue fragments with HeLa cells, ad 6 was always recovered from the brains of hamsters throughout their lives, as long as 29 months, indicating the establishment of a lifelong persistent infection. Except for the first few days after inoculation, however, attempts to recover virus by inoculation of tissue extracts onto HeLa cells or by cultivation of tissue fragments alone were unsuccessful.

  14. Pharmacokinetics and the bystander effect in CD::UPRT/5-FC bi-gene therapy of glioma

    Institute of Scientific and Technical Information of China (English)

    SHI De-zhi; HU Wei-xing; LI Li-xin; CHEN Gong; WEI Dong; GU Pei-yuan

    2009-01-01

    Background Cytosine deaminase (CD) converts 5-fluorocytosine (5-FC) to 5-fluorouracil (5-FU) in CD/5-FC gene therapy, 5-FU will be mostly converted into nontoxic β-alanine without uracil phosphoribosyltransferase (UPRT). UPRT catalyzes the conversion of 5-FU to 5-fluorouridine monophosphate, which directly kills CD::UPRT-expressing ceils and surrounding cells via the bystander effect. But the pharmacokinetics and the bystander effect of CD::UPRT/5-FC has not been verified in vivo and in vitro. Before the CD::UPRT/5-FC bi-gene therapy system is used in clinical trial, it is essential to monitor the transgene expression and function in vivo. Thus, we developed a preclinical tumor model to investigate the feasibility of using 19F-magnetic resonance spectroscopy (19F-MRS) and optical imaging to measure non-invasive CD and UPRT expression and its bystander effect.Methods C6 and C6-CD::UPRT cells were cultured with 5-FC. The medium, cells and their mixture were analyzed by 19F-MRS. Rats with intracranial xenografted encephalic C6-CD::UPRT glioma were injected intraperitoneally with 5-FC and their 19F-MRS spectra recorded. Then the pharmacokinetics of 5-FC was proved. Mixtures of C6 and C6-CD::UPRT cells at different ratios were cultured with 5-FC and the cytotoxic efficacy and survival rate of cells recorded. To determine the mechanism of the bystander effect, the culture media from cell comprising 25% and 75% C6-CD::UPRT cells were examined by19F-MRS. A comparative study of mean was performed using analysis of variance (ANOVA). Results 19F-MRS on samples from C6-CD::UPRT cells cultured with 5-FC showed three broad resonance signals corresponding to 5-FC, 5-FU and fluorinated nucleotides (F-Nuctd). For the C6 mixture, only the 5-FC peak was detected. In vivo serial 19F-MRS spectra showed a strong 5-FC peak and a weak 5-FU peak at 20 minutes after 5-FC injection. The 5-FU concentration reached a maximum at about 50 minutes. The F-Nuctd signal appeared after about I hour

  15. Trends and approaches in N-Glycosylation engineering in Chinese hamster ovary cell culture

    DEFF Research Database (Denmark)

    Fan, Yuzhou; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    will summarize a group of recent strategies andapproaches and come up with case studies for N-glycosylation engineering in CHO cells and show several examples of relevantstudy cases from our research: 1) media and feed design, 2) culture process optimization, 3) substrate addition, 4) geneticengineering, 5...

  16. Trends and approaches in N-Glycosylation engineering in Chinese hamster ovary cell culture

    DEFF Research Database (Denmark)

    Fan, Yuzhou; Kildegaard, Helene Faustrup; Andersen, Mikael Rørdam

    , in particular, of those as drug substances, is extremely concerned in drug development andapproval, as it will largely affect their stability, efficacy, clearance rate and immunogenicity. Therefore to engineering N-glycosylationof CHO cell-derived recombinant proteins are extremely important. Here, we...

  17. Inhibin reduces spermatogonial numbers in testes of adult mice and chinese hamsters

    NARCIS (Netherlands)

    F.M.F van Dissel-Emiliani (F. M F); A.J. Grootenhuis (Arijan); F.H. de Jong (Frank); D.G. de Rooij (Dirk)

    1989-01-01

    textabstractBovine follicular fluid (bFF) injected ip in mice during 2 days (65,000 U inhibin/day, 1 U inhibin the activity in 1 /μg bFF protein) caused a significant decrease in the numbers of A4, intermediate (In), and B spermatogonia to 91%,74%, and 67% of the control values, respectively. The nu

  18. Matrix attachment region combinations increase transgene expression in transfected Chinese hamster ovary cells

    Science.gov (United States)

    Zhao, Chun-Peng; Guo, Xiao; Chen, Si-Jia; Li, Chang-Zheng; Yang, Yun; Zhang, Jun-He; Chen, Shao-Nan; Jia, Yan-Long; Wang, Tian-Yun

    2017-01-01

    Matrix attachment regions (MARs) are cis-acting DNA elements that can increase transgene expression levels in a CHO cell expression system. To investigate the effects of MAR combinations on transgene expression and the underlying regulatory mechanisms, we generated constructs in which the enhanced green fluorescent protein (eGFP) gene flanked by different combinations of human β-interferon and β-globin MAR (iMAR and gMAR, respectively), which was driven by the cytomegalovirus (CMV) or simian virus (SV) 40 promoter. These were transfected into CHO-K1 cells, which were screened with geneticin; eGFP expression was detected by flow cytometry. The presence of MAR elements increased transfection efficiency and transient and stably expression of eGFP expression under both promoters; the level was higher when the two MARs differed (i.e., iMAR and gMAR) under the CMV but not the SV40 promoter. For the latter, two gMARs showed the highest activity. We also found that MARs increased the ratio of stably transfected positive colonies. These results indicate that combining the CMV promoter with two different MAR elements or the SV40 promoter with two gMARs is effective for inducing high expression level and stability of transgenes. PMID:28216629

  19. Generation of a Chinese Hamster Ovary Cell Line Producing Recombinant Human Glucocerebrosidase

    Directory of Open Access Journals (Sweden)

    Juliana Branco Novo

    2012-01-01

    Full Text Available Impaired activity of the lysosomal enzyme glucocerebrosidase (GCR results in the inherited metabolic disorder known as Gaucher disease. Current treatment consists of enzyme replacement therapy by administration of exogenous GCR. Although effective, it is exceptionally expensive, and patients worldwide have a limited access to this medicine. In Brazil, the public healthcare system provides the drug free of charge for all Gaucher’s patients, which reaches the order of $ 84 million per year. However, the production of GCR by public institutions in Brazil would reduce significantly the therapy costs. Here, we describe a robust protocol for the generation of a cell line producing recombinant human GCR. The protein was expressed in CHO-DXB11 (dhfr− cells after stable transfection and gene amplification with methotrexate. As expected, glycosylated GCR was detected by immunoblotting assay both as cell-associated (~64 and 59 kDa and secreted (63–69 kDa form. Analysis of subclones allowed the selection of stable CHO cells producing a secreted functional enzyme, with a calculated productivity of 5.14 pg/cell/day for the highest producer. Although being laborious, traditional methods of screening high-producing recombinant cells may represent a valuable alternative to generate expensive biopharmaceuticals in countries with limited resources.

  20. Survival of Chinese Hamster Ovary Cells Following Ultrahigh Dose Rate Electron and Bremsstrahlung Radiation

    Science.gov (United States)

    1990-04-01

    47Patricia K. Holahan , Ph.D. Martin L. Meltz, Ph.D. University qf Texas Health Science Center 7703 Floyd Curl Drive San Antonio, TX 78284 DTIC A~riI 1q9...AUTHOR(S) Holahan , Patricia K.; and Meltz, Martin L. 13a. TYPE OF REPORT l3b TME COVERED 114. DATE OF REPORT ’Year. :7’-󈧕 5 C . Final O.- 88/9/28 To89/2

  1. Characterization of Chinese Hamster Ovary Cells Producing Coagulation Factor VIII Using Multi-omics Tools

    DEFF Research Database (Denmark)

    Kaas, Christian Schrøder

    ,000 fold over the last couple of years due to the revolution of next-generation sequencing (NGS), has dramatically accelerated CHO-omics from virtually non-existent to a vibrant growing field. The aim of this thesis was to investigate the impact of coagulation factor VIII (FVIII) production in CHO cells...... for analysis and engineering of industrially relevant CHO cells. Full implementation of such tools for generating specifically engineered CHO production cell lines may allow significant cost-reductions in production of complex biopharmaceuticals such as FVIII....

  2. In Vitro Chromosome Aberrations Study in Chinese Hamster Ovary (CHO) Cells

    Science.gov (United States)

    2016-06-07

    activity offE-13. The mouse bone micronucleus assay is an in vivo test system which can determine the ability of a compound to induce micronuclei...CELLS Project No. ILS A073-004 Sponsor’s Study Number DAADOS-91-C-00 18 Test Substance FE-13 ILS Repository No. 96-01 Final Report Date May...24, 1996 Sponsor U.S. CHPPM Bldg. E-21 00 Aberdeen Proving Ground, MD 21005 Testing Facility Integrated Laboratory Systems 800-12 Capitola

  3. A theoretical estimate for nucleotide sugar demand towards Chinese Hamster Ovary cellular glycosylation

    Science.gov (United States)

    del Val, Ioscani Jimenez; Polizzi, Karen M.; Kontoravdi, Cleo

    2016-01-01

    Glycosylation greatly influences the safety and efficacy of many of the highest-selling recombinant therapeutic proteins (rTPs). In order to define optimal cell culture feeding strategies that control rTP glycosylation, it is necessary to know how nucleotide sugars (NSs) are consumed towards host cell and rTP glycosylation. Here, we present a theoretical framework that integrates the reported glycoproteome of CHO cells, the number of N-linked and O-GalNAc glycosylation sites on individual host cell proteins (HCPs), and the carbohydrate content of CHO glycosphingolipids to estimate the demand of NSs towards CHO cell glycosylation. We have identified the most abundant N-linked and O-GalNAc CHO glycoproteins, obtained the weighted frequency of N-linked and O-GalNAc glycosites across the CHO cell proteome, and have derived stoichiometric coefficients for NS consumption towards CHO cell glycosylation. By combining the obtained stoichiometric coefficients with previously reported data for specific growth and productivity of CHO cells, we observe that the demand of NSs towards glycosylation is significant and, thus, is required to better understand the burden of glycosylation on cellular metabolism. The estimated demand of NSs towards CHO cell glycosylation can be used to rationally design feeding strategies that ensure optimal and consistent rTP glycosylation. PMID:27345611

  4. Reduced cytotoxicity in PCB-exposed Chinese Hamster Ovary (CHO) cells pretreated with vitamin E.

    Science.gov (United States)

    Murati, Teuta; Šimić, Branimir; Pleadin, Jelka; Vukmirović, Maja; Miletić, Marina; Durgo, Ksenija; Kniewald, Jasna; Kmetič, Ivana

    2017-01-01

    The aim of this study was to evaluate protective effects of vitamin E (50 -150 μM) in ovary cells upon cytotoxic effects induced by two structurally distinct PCB congeners - planar "dioxin-like" PCB 77 and non-planar di-ortho-substituted PCB 153 with an emphasis on identifying differences in the mechanism of vitamin E action depending on the structure of congeners. Application of three bioassays confirmed that PCBs decrease ovarian cell proliferation with slightly profound effects of PCB 77. PCB - induced ROS production and lipid peroxidation were significant for both congeners with also more noticeable effect for PCB 77. Vitamin E pre-incubation has improved viability of cells, reduced ROS formation and lipid peroxidation induced by PCBs' treatment. Preincubation with vitamin E was more effective when cells where treated with non-planar PCB 153. Altogether, vitamin E action was protective, congener specific and more effective when ovary cells were exposed to ortho-substituted PCB congener.

  5. Gene linkage in man and chinese hamster studied in somatic cell hybrids

    NARCIS (Netherlands)

    Westerveld, A.

    1971-01-01

    Genetic studies of higher organisms, including man, are based on the analysis of segregation and recombination events resulting from reproduction. In 1962 Pontecorvo predicted, however, that cultured cells could also be employed for this purpose. He suggested that "events, detected in certain fungi,

  6. Heterologous expression of rat testis GABAA receptor βt variant in Chinese hamster ovary cells

    Institute of Scientific and Technical Information of China (English)

    Shi-FengLi; Yu-GuangChen; Yuan-ChangYan; Yi-PingLi

    2004-01-01

    Aim: To study the characteristics and possible retention functionof specific sequence in the 5'-end of rat testis GABAA receptor β 3t variant, Methods: Rat testis GABAA receptor β 3t variant cDNA was cloned and inserted into two eukaryotic expression vectors of pEGFP-N1 and pEGFP-C1 respectively, which have EGFP reporter gene.

  7. Small CD4 Mimetics Prevent HIV-1 Uninfected Bystander CD4+ T Cell Killing Mediated by Antibody-dependent Cell-mediated Cytotoxicity

    Directory of Open Access Journals (Sweden)

    Jonathan Richard

    2016-01-01

    Full Text Available Human immunodeficiency virus type 1 (HIV-1 infection causes a progressive depletion of CD4+ T cells. Despite its importance for HIV-1 pathogenesis, the precise mechanisms underlying CD4+ T-cell depletion remain incompletely understood. Here we make the surprising observation that antibody-dependent cell-mediated cytotoxicity (ADCC mediates the death of uninfected bystander CD4+ T cells in cultures of HIV-1-infected cells. While HIV-1-infected cells are protected from ADCC by the action of the viral Vpu and Nef proteins, uninfected bystander CD4+T cells bind gp120 shed from productively infected cells and are efficiently recognized by ADCC-mediating antibodies. Thus, gp120 shedding represents a viral mechanism to divert ADCC responses towards uninfected bystander CD4+ T cells. Importantly, CD4-mimetic molecules redirect ADCC responses from uninfected bystander cells to HIV-1-infected cells; therefore, CD4-mimetic compounds might have therapeutic utility in new strategies aimed at specifically eliminating HIV-1-infected cells.

  8. DNA damaging bystander signalling from stem cells, cancer cells and fibroblasts after Cr(VI) exposure and its dependence on telomerase

    Energy Technology Data Exchange (ETDEWEB)

    Cogan, Nicola [Bristol Implant Research Centre, University of Bristol, Bristol, BS10 5NB (United Kingdom); Baird, Duncan M. [Department of Pathology School of Medicine, Cardiff University, Henry Wellcome Building for Biomedical Research in Wales, Heath Park, Cardiff, CF14 4XN (United Kingdom); Phillips, Ryan [Bristol Implant Research Centre, University of Bristol, Bristol, BS10 5NB (United Kingdom); Crompton, Lucy A.; Caldwell, Maeve A. [Henry Wellcome Laboratories for Integrative Neuroscience and Endocrinology, University of Bristol, Bristol, BS1 3NY (United Kingdom); Rubio, Miguel A. [Center of Regenerative Medicine in Barcelona, CMRB Dr. Aiguader, 88, 7th Floor, 08003 Barcelona (Spain); Newson, Roger [Radiation and Environmental Science Centre, Focas Institute, Dublin Institute of Technology, Dublin 2 (Ireland); Lyng, Fiona [National Heart and Lung Institute, Imperial College London, London, SW7 2AZ (United Kingdom); Case, C. Patrick, E-mail: c.p.case@bristol.ac.uk [Bristol Implant Research Centre, University of Bristol, Bristol, BS10 5NB (United Kingdom)

    2010-01-05

    The bystander effect is a feature of low dose radiation exposure and is characterized by a signaling process from irradiated cells to non irradiated cells, which causes DNA and chromosome damage in these 'nearest neighbour' cells. Here we show that a low and short dose of Cr(VI) can induce stem cells, cancer cells and fibroblasts to chronically secrete bystander signals, which cause DNA damage in neighboring cells. The Cr(VI) induced bystander signaling depended on the telomerase status of either cell. Telomerase negative fibroblasts were able to receive DNA damaging signals from telomerase positive or negative fibroblasts or telomerase positive cancer cells. However telomerase positive fibroblasts were resistant to signals from Cr(VI) exposed telomerase positive fibroblasts or cancer cells. Human embryonic stem cells, with positive Oct4 staining as a marker of pluripotency, showed no significant increase of DNA damage from adjacent Cr and mitomycin C exposed fibroblasts whilst those cells that were negatively stained did. This selectivity of DNA damaging bystander signaling could be an important consideration in developing therapies against cancer and in the safety and effectiveness of tissue engineering and transplantation using stem cells.

  9. SirT1 knockdown potentiates radiation-induced bystander effect through promoting c-Myc activity and thus facilitating ROS accumulation.

    Science.gov (United States)

    Xie, Yuexia; Tu, Wenzhi; Zhang, Jianghong; He, Mingyuan; Ye, Shuang; Dong, Chen; Shao, Chunlin

    2015-02-01

    Radiation-induced bystander effect (RIBE) has important implications for secondary cancer risk assessment during cancer radiotherapy, but the bystander signaling processes, especially under hypoxic condition, are still largely unclear. The present study found that micronuclei (MN) formation could be induced in the non-irradiated HL-7702 hepatocyte cells after being treated with the conditioned medium from irradiated hepatoma HepG2 and SK-Hep-1 cells under either normoxia or hypoxia. This bystander response was dramatically diminished or enhanced when the SirT1 gene of irradiated hepatoma cells was overexpressed or knocked down, respectively, especially under hypoxia. Meanwhile, SirT1 knockdown promoted transcriptional activity for c-Myc and facilitated ROS accumulation. But both of the increased bystander responses and ROS generation due to SirT1-knockdown were almost completely suppressed by c-Myc interference. Moreover, ROS scavenger effectively abolished the RIBE triggered by irradiated hepatoma cells even with SirT1 depletion. These findings provide new insights that SirT1 has a profound role in regulating RIBE where a c-Myc-dependent release of ROS may be involved.

  10. An NSF rotator's perspective: view from inside the hamster wheel

    Science.gov (United States)

    White, Gary

    2015-03-01

    Duncan McBride served as my unofficial mentor during my time at NSF as a ``rotator'' (or, in NSF-speak, an IPA, short for an Intergovernmental Personnel Act assignee), from fall 2012 through summer of 2013. A rotator's main job is to help keep the wheels of the grant submission process turning, shepherding individual proposal jackets through the submission cycle. While most proposals are eventually ``Declined'' it is the few that are funded that evoke the most vivid memories of my time there. I hope to relay a little bit about what that was like on a daily basis, to give one hamster's take on the machinations of the NSF machine, and testify to Duncan McBride's critical role in establishing physics as the leader in disciplinary based educational research (DBER). It was a heady experience in many ways, despite the sheer girth of proposal jackets to be processed and the uncertain footing upon which federal employees tread these days.

  11. Arsenite exposure compromises early embryonic development in the Golden hamster.

    Science.gov (United States)

    Unis, Dave; Osborne, Cassandra; Diawara, Moussa M

    2009-11-01

    The toxicity of arsenite to 8-cell stage hamster embryos was evaluated. Females were superovulated and mated; embryos were collected and grown for 72 h in culture medium containing vehicle control, 25, 50, 250, 500, or 750 nM arsenite. Morphological observations were taken at 0 and 24h increments. A TUNEL assay was used for determining DNA damage. Survival was expressed by the ability to undergo zona escape. The control group had 78% survival and no evidence of deformities. Embryos in the 25, 50 and 250 nM groups had survival rates of 63%, 55% and 27%, respectively. Arsenite exposure caused total embryo lethality, major deformities, complete failure to undergo zona lysis, and significantly higher number of cells with fragmented DNA in embryos at the 500 and 750 nM concentrations. The study underscores the sensitivity of preimplantation stage embryos to the presence of even relatively small amounts of arsenic in luminal fluid.

  12. Kisspeptin and the seasonal control of reproduction in hamsters

    DEFF Research Database (Denmark)

    Simonneaux, Valérie; Ansel, Laura; Revel, Florent G

    2008-01-01

    Reproduction is a complex and energy demanding function. When internal and external conditions might impair reproductive success (negative energy balance, stress, harsh season) reproductive activity has to be repressed. Recent evidence suggests that these inhibitory mechanisms operate on Kiss1......-expressing neurons, which were recently shown to be implicated in the regulation of GnRH release. Hamsters are seasonal rodents which are sexually active in long photoperiod and quiescent in short photoperiod. The photoperiodic information is transmitted to the reproductive system by melatonin, a pineal...... hormone whose secretion is adjusted to night length. The photoperiodic variation in circulating melatonin has been shown to synchronize reproductive activity with seasons, but the mechanisms involved in this effect of melatonin were so far unknown. Recently we have observed that Kiss1 mRNA level...

  13. Estudios inmunologicos en hamsters (Cricetus auratus infectados con Schistosoma mansoni

    Directory of Open Access Journals (Sweden)

    Eduardo Monge

    1986-08-01

    Full Text Available Los resultados de este trabajo muestran que el hamster (Cricetus auratus puede ser utilizado como un modelo experimental para estudios inmunológicos en la infección por Schistosoma mansoni. Los datos obtenidos, relativos a inmunidad concomitante, producción de anticuerpo letal e inmunosupresión se asemejan a los conseguidos en otros modelos experimentales ya establecidos. Estas observaciones indican que el hámster, además de ser un hospedero satisfactorio para el mantenimiento del parásito en el laboratorio, puede ser considerado como un modelo experimental alterno cuyo crecimiento y mantenimiento son relativamente simples y además es un animal de fácil manejo.

  14. Photoperiod Regulates vgf-Derived Peptide Processing in Siberian Hamsters.

    Science.gov (United States)

    Noli, Barbara; Brancia, Carla; Pilleri, Roberta; D'Amato, Filomena; Messana, Irene; Manconi, Barbara; Ebling, Francis J P; Ferri, Gian-Luca; Cocco, Cristina

    2015-01-01

    VGF mRNA is induced in specific hypothalamic areas of the Siberian hamster upon exposure to short photoperiods, which is associated with a seasonal decrease in appetite and weight loss. Processing of VGF generates multiple bioactive peptides, so the objective of this study was to determine the profile of the VGF-derived peptides in the brain, pituitary and plasma from Siberian hamsters, and to establish whether differential processing might occur in the short day lean state versus long day fat. Antisera against short sequences at the C- or N- termini of proVGF, as well as against NERP-1, TPGH and TLQP peptides, were used for analyses of tissues, and both immunohistochemistry and enzyme linked immunosorbent assay (ELISA) coupled with high-performance liquid (HPLC) or gel chromatography were carried out. VGF peptide immunoreactivity was found within cortex cholinergic perikarya, in multiple hypothalamic nuclei, including those containing vasopressin, and in pituitary gonadotrophs. ELISA revealed that exposure to short day photoperiod led to a down-regulation of VGF immunoreactivity in the cortex, and a less pronounced decrease in the hypothalamus and pituitary, while the plasma VGF levels were not affected by the photoperiod. HPLC and gel chromatography both confirmed the presence of multiple VGF-derived peptides in these tissues, while gel chromatography showed the presence of the VGF precursor in all tissues tested except for the cortex. These observations are consistent with the view that VGF-derived peptides have pleiotropic actions related to changing photoperiod, possibly by regulating cholinergic systems in the cortex, vasopressin hypothalamic pathways, and the reproductive axis.

  15. Photoperiod Regulates vgf-Derived Peptide Processing in Siberian Hamsters.

    Directory of Open Access Journals (Sweden)

    Barbara Noli

    Full Text Available VGF mRNA is induced in specific hypothalamic areas of the Siberian hamster upon exposure to short photoperiods, which is associated with a seasonal decrease in appetite and weight loss. Processing of VGF generates multiple bioactive peptides, so the objective of this study was to determine the profile of the VGF-derived peptides in the brain, pituitary and plasma from Siberian hamsters, and to establish whether differential processing might occur in the short day lean state versus long day fat. Antisera against short sequences at the C- or N- termini of proVGF, as well as against NERP-1, TPGH and TLQP peptides, were used for analyses of tissues, and both immunohistochemistry and enzyme linked immunosorbent assay (ELISA coupled with high-performance liquid (HPLC or gel chromatography were carried out. VGF peptide immunoreactivity was found within cortex cholinergic perikarya, in multiple hypothalamic nuclei, including those containing vasopressin, and in pituitary gonadotrophs. ELISA revealed that exposure to short day photoperiod led to a down-regulation of VGF immunoreactivity in the cortex, and a less pronounced decrease in the hypothalamus and pituitary, while the plasma VGF levels were not affected by the photoperiod. HPLC and gel chromatography both confirmed the presence of multiple VGF-derived peptides in these tissues, while gel chromatography showed the presence of the VGF precursor in all tissues tested except for the cortex. These observations are consistent with the view that VGF-derived peptides have pleiotropic actions related to changing photoperiod, possibly by regulating cholinergic systems in the cortex, vasopressin hypothalamic pathways, and the reproductive axis.

  16. Ductuli efferentes of the male Golden Syrian hamster reproductive tract.

    Science.gov (United States)

    Ford, J; Carnes, K; Hess, R A

    2014-07-01

    Efferent ductules are responsible for the transportation of spermatozoa from the testis to the epididymis and their epithelium is responsible for the reabsorption of over 90% of the luminal fluid. The purpose of this research was to characterize the gross morphology and histology of efferent ductules in the male Golden Syrian hamster. The efferent ductules emerge from rete testis with a unique polarity at the apex or cephalic pole of the testis. The number of efferent ductules varied from 3 to 10 with an average of 6.0 and blind ending ducts were observed in approximately 56% of the males. The ductules merged into a single common duct prior to entering the caput epididymidis. The proximal efferent ductule lumen was wider than the distal (conus and common ducts), consistent with reabsorption of most of the luminal fluid, as was morphology of the ductal epithelium. Non-ciliated cells in the proximal region had prominent endocytic apparatuses, showing both coated pits and apical tubules in the apical cytoplasm. Large basolateral, intercellular spaces were also present in the epithelium of the proximal region. Distal non-ciliated cells had an abundance of large endosomes and lysosomal granules. Localisation of sodium/hydrogen exchanger-3 (NHE3; SLC9A3) and aquaporins 1 and 9 (AQP1, AQP9) along the microvillus border was also consistent with ion transport and fluid reabsorption by this epithelium. In comparison, the caput epididymidis epithelium expressed only AQP9 immunostaining. Another unusual feature of the hamster efferent ductules was the presence of glycogen aggregates in the basal cytoplasm of small groups of epithelial cells, but only in the proximal ducts near the rete testis. Androgen (AR), estrogen (ESR1 and ESR2) and vitamin D receptors (VDR) were also abundant in epithelial nuclei of proximal and distal efferent ductules. In comparison, caput epididymidis showed very little immunostaining for ESR1.

  17. Effects of pharmacological manipulation of GABAergic neurotransmission in a new mutant hamster model of paroxysmal dystonia.

    Science.gov (United States)

    Fredow, G; Löscher, W

    1991-01-10

    Attacks of sustained dystonic postures of limbs and trunk can be initiated by handling or mild environmental stimuli (e.g. new cage) in an inbred line of Syrian hamsters. The severity of the dystonic syndrome in these mutant hamsters (gene symbol dtsz) is age-dependent, with a peak at about 30-40 days of age. A scoring system for grading type and severity of the dystonic attacks can be used to study the activity of drugs against dystonic movements with individual pre- and post-drug vehicle trials as control. In the present experiments, the effects of drugs which alter GABAergic functions in the brain were studied in dystonic hamsters. Anticonvulsants, i.e. valproate, diazepam and phenobarbital, which augment GABAergic neurotransmission, decreased the severity of dystonic attacks in the mutant hamsters, while administration of subconvulsive doses of pentylenetetrazol or the inverse benzodiazepine receptor agonist FG 7142 increased the severity of the syndrome. Anticonvulsants, i.e. phenytoin and carbamazepine, which are not thought to act via effects on GABAergic neurotransmission, exerted no antidystonic effects, but even worsened the attack in several animals. In contrast, the GABA-elevating drug, aminooxyacetic acid, produced a marked antidystonic effect in the hamsters. Similarly, the GABAB receptor agonist, baclofen, significant decreased the severity of the dystonic attack. The data indicate that dystonic movements in dtsz mutant hamsters can be attenuated by drugs which facilitate GABAergic functions, but worsened by drugs which impair GABAergic neurotransmission. These data thus seem to suggest that the dystonic syndrome in dtsz mutant hamsters is under GABAergic influence. The data show furthermore that dystonic hamsters are a suitable model to detect antidystonic effects of drugs.

  18. Hematologic assessment in pet rats, mice, hamsters, and gerbils: blood sample collection and blood cell identification.

    Science.gov (United States)

    Lindstrom, Nicole M; Moore, David M; Zimmerman, Kurt; Smith, Stephen A

    2015-01-01

    Hamsters, gerbils, rats, and mice are presented to veterinary clinics and hospitals for prophylactic care and treatment of clinical signs of disease. Physical examination, history, and husbandry practice information can be supplemented greatly by assessment of hematologic parameters. As a resource for veterinarians and their technicians, this article describes the methods for collection of blood, identification of blood cells, and interpretation of the hemogram in mice, rats, gerbils, and hamsters.

  19. Effects of Porcine Pancreatic Enzymes on the Pancreas of Hamsters. Part 2: Carcinogenesis Studies

    OpenAIRE

    2012-01-01

    Context Our previous study suggested that porcine pancreatic extract in hamsters with peripheral insulin resistance, normalizes insulin output, islet size and pancreatic DNA synthetic rate. It also inhibited the growth of human pancreatic cancer cells in nude mice. Objective To examine the potential value of the porcine pancreatic extract in controlling pancreatic carcinogenesis in this model, the present experiment was performed. Design Hamsters were fed a high fat diet and four wee...

  20. Leptin mediates seasonal variation in some but not all symptoms of sickness in Siberian hamsters.

    Science.gov (United States)

    Carlton, Elizabeth D; Demas, Gregory E

    2014-11-01

    Many seasonally breeding species, including Siberian hamsters (Phodopus sungorus), exhibit seasonal variation in sickness responses. One hypothesis regarding the mechanism of this variation is that sickness intensity tracks an animal's energetic state, such that sickness is attenuated in the season that an animal has the lowest fat stores. Energetic state may be signaled via leptin, an adipose hormone that provides a signal of fat stores. Siberian hamsters respond to extended housing in short, winter-like days by reducing fat stores and leptin levels, relative to those housed in long, summer-like days. Sickness responses are also attenuated in short-day hamsters as compared to long-day hamsters. We hypothesized that leptin provides a physiological signal by which seasonally breeding animals modulate sickness responses, such that animals with higher leptin levels show increased sickness intensity. To test this, we provided short-day hamsters with a long-day-like leptin signal and assessed their responses to lipopolysaccharide (LPS), a sickness-inducing antigen. We compared these responses to short-day vehicle-, long-day vehicle-, and long-day leptin-treated hamsters. Unexpectedly, LPS induced a hypothermic response (rather than fever) in all groups. Short-day vehicle-treated hamsters exhibited the greatest LPS-induced hypothermia, and leptin treatment attenuated this response, making hypothermia more long-day-like. Contrary to our hypothesis, short-day leptin-treated hamsters showed the least pronounced LPS-induced anorexia among all groups. These results suggest that leptin may mediate some but not all aspects of seasonal sickness variation in this species. Future studies should be targeted at determining roles of other energetic hormones in regulating seasonal sickness response variation.

  1. Response of Gut Microbiota to Fasting and Hibernation in Syrian Hamsters

    OpenAIRE

    Sonoyama, Kei; Fujiwara, Reiko; Takemura, Naoki; Ogasawara, Toru; Watanabe, Jun; Ito, Hiroyuki; Morita, Tatsuya

    2009-01-01

    Although hibernating mammals wake occasionally to eat during torpor, this period represents a state of fasting. Fasting is known to alter the gut microbiota in nonhibernating mammals; therefore, hibernation may also affect the gut microbiota. However, there are few reports of gut microbiota in hibernating mammals. The present study aimed to compare the gut microbiota in hibernating torpid Syrian hamsters with that in active counterparts by using culture-independent analyses. Hamsters were all...

  2. Experimental infection of hamsters with avian paramyxovirus serotypes 1 to 9

    Directory of Open Access Journals (Sweden)

    Samuel Arthur S

    2011-02-01

    Full Text Available Abstract Avian paramyxoviruses (APMVs are frequently isolated from domestic and wild birds throughout the world and are separated into nine serotypes (APMV-1 to -9. Only in the case of APMV-1, the infection of non-avian species has been investigated. The APMVs presently are being considered as human vaccine vectors. In this study, we evaluated the replication and pathogenicity of all nine APMV serotypes in hamsters. The hamsters were inoculated intranasally with each virus and monitored for clinical disease, pathology, histopathology, virus replication, and seroconversion. On the basis of one or more of these criteria, each of the APMV serotypes was found to replicate in hamsters. The APMVs produced mild or inapparent clinical signs in hamsters except for APMV-9, which produced moderate disease. Gross lesions were observed over the pulmonary surface of hamsters infected with APMV-2 & -3, which showed petechial and ecchymotic hemorrhages, respectively. Replication of all of the APMVs except APMV-5 was confirmed in the nasal turbinates and lungs, indicating a tropism for the respiratory tract. Histologically, the infection resulted in lung lesions consistent with bronchointerstitial pneumonia of varying severity and nasal turbinates with blunting or loss of cilia of the epithelium lining the nasal septa. The majority of APMV-infected hamsters exhibited transient histological lesions that self resolved by 14 days post infection (dpi. All of the hamsters infected with the APMVs produced serotype-specific HI or neutralizing antibodies, confirming virus replication. Taken together, these results demonstrate that all nine known APMV serotypes are capable of replicating in hamsters with minimal disease and pathology.

  3. Use of hamster as a model to study diet-induced atherosclerosis

    Directory of Open Access Journals (Sweden)

    Lichtenstein Alice H

    2010-12-01

    Full Text Available Abstract Golden-Syrian hamsters have been used as an animal model to assess diet-induced atherosclerosis since the early 1980s. Advantages appeared to include a low rate of endogenous cholesterol synthesis, receptor-mediated uptake of LDL cholesterol, cholesteryl ester transfer protein activity, hepatic apoB-100 and intestinal apoB-48 secretion, and uptake of the majority of LDL cholesterol via the LDL receptor pathway. Early work suggested hamsters fed high cholesterol and saturated fat diets responded similarly to humans in terms of lipoprotein metabolism and aortic lesion morphology. Recent work has not consistently replicated these findings. Reviewed was the literature related to controlled hamster feeding studies that assessed the effect of strain, background diet (non-purified, semi-purified and dietary perturbation (cholesterol and/or fat on plasma lipoprotein profiles and atherosclerotic lesion formation. F1B hamsters fed a non-purified cholesterol/fat-supplemented diet had more atherogenic lipoprotein profiles (nHDL-C > HDL-C than other hamster strains or hamsters fed cholesterol/fat-supplemented semi-purified diets. However, fat type; saturated (SFA, monounsaturated or n-6 polyunsaturated (PUFA had less of an effect on plasma lipoprotein concentrations. Cholesterol- and fish oil-supplemented semi-purified diets yielded highly variable results when compared to SFA or n-6 PUFA, which were antithetical to responses observed in humans. Dietary cholesterol and fat resulted in inconsistent effects on aortic lipid accumulation. No hamster strain was reported to consistently develop lesions regardless of background diet, dietary cholesterol or dietary fat type amount. In conclusion, at this time the Golden-Syrian hamster does not appear to be a useful model to determine the mechanism(s of diet-induced development of atherosclerotic lesions.

  4. Serum amyloid P (female protein) of the Syrian hamster. Gene structure and expression.

    Science.gov (United States)

    Rudnick, C M; Dowton, S B

    1993-10-15

    The structure and expression of the gene encoding serum amyloid P (SAP) component of the Syrian hamster have been studied by isolation of cosmid clones, nucleotide sequence analyses, and quantitation of nuclear run-on transcripts, nuclear RNA, mRNA, and protein levels. Hamster SAP, originally identified as female protein (FP), is a unique pentraxin because pretranslational expression of this gene is modulated by mediators of inflammation and sex steroids. SAP(FP) levels are high in sera from female hamsters and low in males. The response to inflammation is divergent; SAP(FP) levels decrease in females and increase in males during an acute phase response. The SAP(FP) gene encodes a 211 amino acid residue mature polypeptide as well as a 22-residue signal peptide. The intron/exon organization is similar to that of other pentraxins, but additional transcripts are generated from alternate polyadenylation sites in the 3' region. Circulating levels of SAP(FP) and the corresponding hepatic transcript levels are augmented by estrogen, while testosterone, dexamethasone, and progesterone cause a decrease in these levels. In addition the cytokines interleukin-1, -6, and tumor necrosis factor mediate a decrease in hepatic SAP(FP) transcript levels in female hamsters but did not cause a significant elevation of SAP(FP) mRNA in livers of male hamsters. The differences in expression of the SAP(FP) gene between male and female hamsters and between unstimulated male hamsters and male hamsters stimulated with an injection of lipopolysaccharide are due, at least in part, to alterations in transcription.

  5. Beneficial effects of noni (Morinda citrifolia L.) juice on livers of high-fat dietary hamsters.

    Science.gov (United States)

    Lin, Yi-Ling; Chang, Yuan-Yen; Yang, Deng-Jye; Tzang, Bor-Show; Chen, Yi-Chen

    2013-09-01

    Polyphenols in noni juice (NJ) are mainly composed of phenolic acids, mainly gentisic, p-hydroxybenoic, and chlorogenic acids. To investigate the beneficial effects of NJ on the liver, hamsters were fed with two diets, normal-fat and high-fat diets. Furthermore, high-fat dietary hamsters were received distilled water, and 3, 6, and 9 mL NJ/kg BW, respectively. After a 6-week feeding period, the increased (p<0.05) sizes of liver and visceral fat in high-fat dietary hamsters compared to the control hamsters were ameliorated (p<0.05) by NJ supplementation. NJ also decreased (p<0.05) serum/liver lipids but enhanced (p<0.05) daily faecal lipid/bile acid outputs in the high-fat dietary hamsters. High-fat dietary hamsters supplemented with NJ had higher (p<0.05) liver antioxidant capacities but lowered (p<0.05) liver iNOS, COX-2, TNF-α, and IL-1β expressions, gelatinolytic levels of MMP9, and serum ALT values compared to those without NJ. Hence, NJ protects liver against a high-fat dietary habit via regulations of antioxidative and anti-inflammatory responses.

  6. Individual differences in circadian waveform of Siberian hamsters under multiple lighting conditions.

    Science.gov (United States)

    Evans, Jennifer A; Elliott, Jeffrey A; Gorman, Michael R

    2012-10-01

    Because the circadian clock in the mammalian brain derives from a network of interacting cellular oscillators, characterizing the nature and bases of circadian coupling is fundamental to understanding how the pacemaker operates. Various phenomena involving plasticity in circadian waveform have been theorized to reflect changes in oscillator coupling; however, it remains unclear whether these different behavioral paradigms reference a unitary underlying process. To test whether disparate coupling assays index a common mechanism, we examined whether there is covariation among behavioral responses to various lighting conditions that produce changes in circadian waveform. Siberian hamsters, Phodopus sungorus, were transferred from long to short photoperiods to distinguish short photoperiod responders (SP-R) from nonresponders (SP-NR). Short photoperiod chronotyped hamsters were subsequently transferred, along with unselected controls, to 24-h light:dark:light: dark cycles (LDLD) with dim nighttime illumination, a procedure that induces bifurcated entrainment. Under LDLD, SP-R hamsters were more likely to bifurcate their rhythms than were SP-NR hamsters or unselected controls. After transfer from LDLD to constant dim light, SP-R hamsters were also more likely to become arrhythmic compared to SP-NR hamsters and unselected controls. In contrast, short photoperiod chronotype did not influence more transient changes in circadian waveform. The present data reveal a clear relationship in the plasticity of circadian waveform across 3 distinct lighting conditions, suggesting a common mechanism wherein individual differences reflect variation in circadian coupling.

  7. A survey on intestinal parasites of golden hamster (Mesocricetus auratus) in the northeast of Iran.

    Science.gov (United States)

    Borji, Hassan; Khoshnegah, Javad; Razmi, Gholamreza; Amini, Hossein; Shariatzadeh, Mahnaz

    2014-09-01

    The aims of this study were to provide baseline knowledge about gastrointestinal parasites in golden hamster (Mesocricetus auratus) that inhabit the Mashhad area, and to analyze possible independent variable from October 2011-August 2012. To determine the prevalence of intestinal parasites in golden hamster, faecal samples were tested specifically for nematode eggs, protozoan oocysts and sporocysts utilizing a combined sedimentation-flotation technique. In addition, all fecal samples were examined to detect oocysts of Cryptosporidium spp. using modified Ziehl-Neelsen staining. Of 100 golden hamsters, 52 % were females and 48 % males. Of all examined fecal samples of golden hamsters, 44 % (95 % CI: 34.3-53.7 %) were found to harbor at least one parasite species. The following parasites were detected (with their respective prevalence): undetermined Trichurata (42 %, 95 % CI: 29.5-48.5 %), Syphacia spp. (4.3 %, 95 % CI: 1-7.3 %). Cryptosporidium and protozoan oocysts were not found in these animals. There was no significant difference (p > 0.05) between age, sex, litter, breeding place, breeding style and anthelminthic treatment with individual helminth infection in faecal examination. This is the first record of the gastrointestinal parasites of golden hamster in Iran. Considering that hamster and other rodents are pets in many homes, the likelihood of cross-infections, particularly involving children and mainly due to unhygienic habits, should be determined.

  8. [Influence of the sex of the final host on experimental Dipetalonema vitae filariosis in golden hamsters Cricetus auratus (author's transl)].

    Science.gov (United States)

    Reynouard, F; Barrabes, A; Combescot, C

    1979-01-01

    The authors have studied the influence of the sex of the host on experimental Dipetalonema viteae parasitosis in golden hamsters Cricetus auratus. The parasited hamsters are sacrificed fifteen days after testing for microfilarial count, and then the extent of the infestation is measured by counting the number of male worms and female worms. The average level of microfilarial count is significantly higher in male hamsters than in female hamsters. The same applies to the extent of parasitism: the average number of adult worms is higher when parasitosis occurs in males. However, the sex of the hamster has no influence on the proportion of male and female worms present and the degree of microfilarial count, observed in male hamsters seems to result only from the presence in the same of a greater number of worms.

  9. Surface-assembled poly(I:C) on PEGylated PLGA microspheres as vaccine adjuvant: APC activation and bystander cell stimulation.

    Science.gov (United States)

    Hafner, Annina M; Corthésy, Blaise; Textor, Marcus; Merkle, Hans P

    2016-11-30

    Biodegradable poly(lactic-co-glycolic acid) (PLGA) microspheres are potential vehicles to deliver antigens for vaccination. Because they lack the full capacity to activate professional antigen presenting cells (APCs), combination with an immunostimulatory adjuvant may be considered. A candidate is the synthetic TLR3 ligand polyriboinosinic acid-polyribocytidylic acid, poly(I:C), which drives cell-mediated immunity. However, poly(I:C) has also been linked to the pathogenesis of autoimmunity, as affected by widespread stimulation of non-hematopoietic bystander cells. To address this aspect, we propose to minimize the poly(I:C) dose as well as to control the stimulation of non-immune bystander cells by poly(I:C). To facilitate the maturation of APCs with minimal poly(I:C) doses, we surface-assembled poly(I:C) onto PLGA microspheres. The microspheres' surface was further modified by poly(ethylene glycol) (PEG) coronas with varying PEG-densities. PLGA microspheres loaded with tetanus toxoid (tt) as model antigen were manufactured by microextrusion-based solvent extraction. The negatively charged PLGA(tt) microspheres were coated with polycationic poly(l-lysine) (PLL) polymers, either PLL itself or PEG-grafted PLL (PLL-g-PEG) with varying grafting ratios (g=2.2 and g=10.1). Stable surface assembly of poly(I:C) was achieved by subsequent incubation of polymer-coated PLGA microspheres with aqueous poly(I:C) solutions. We evaluated the immunostimulatory potential of such PLGA(tt) microsphere formulations on monocyte-derived dendritic cells (MoDCs) as well as human foreskin fibroblasts (HFFs) as model for non-hematopoietic bystander cells. Formulations with surface-assembled poly(I:C) readily activated MoDCs with respect to the expression of maturation-related surface markers, proinflammatory cytokine secretion and directed migration. When surface-assembled, poly(I:C) enhanced its immunostimulatory activity by more than one order of magnitude as compared to free poly

  10. Anti-liver cancer activity of TNF-related apoptosis-inducing ligand gene and its bystander effects

    Institute of Scientific and Technical Information of China (English)

    Chao He; Wei-Feng Lao; Xiao-Tong Hu; Xiang-Ming Xu; Jing Xu; Bing-Liang Fang

    2004-01-01

    AIM: To observe the anti-liver cancer activity of tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene and its bystander effects on hepatocellular carcinoma (HCC) cell line SMMC7721.METHODS: Full-length cDNA of human TRAIL was transferred into SMMC7721 cells with a binary adenoviral vector system.Polymerase-chain reaction following reverse transcription (RT-PCR) was used to determine the expression of TRAIL gene. Effects of the transfected gene on proliferation of SMMC7721 cells were measured by MTT assay. Its influence on apoptosis was demonstrated by fluorescence-activated cell sorting (FACS). The bystander effect was observed by co-culturing the SMNC7721 cells with and without the transfected TRAIL gene at different ratios, and the culture medium supernatant from the transfected cells was also examined for its influence on SMMC7721 cells.RESULTS: The growth-inhibition rate and apoptotic cell fraction in the cells transfected with the TRAIL gene, Bax gene or only LacZ gene were 91.2%, 48.0%, 28.8% and 29.1%, 12.5%, 6.6%, respectively. The growth-inhibition rate of transfection with these three sequences in normal human fibroblasts was 6.1%, 45.5% and 7.6%, respectively,indicating a discriminative inhibition of TRAIL transfection on the cancer cells. In the co-culturing test, addition of the transfected TRAIL to SMMC7721 cells in proportions of 5%,25%, 50%, 75% and 100%, resulted in a growth-inhibition of 15.9%, 67%, 80.2%, 86.4% and 87.7%, respectively.We failed to observe a significant growth-inhibition effect of the culture medium supernatant on SMMC7721 cells.CONCLUSION: TRAIL gene transferred by a binary adenoviral vector system can inhibit proliferation of SMMC7721 cells and induce their apoptosis. A bystander effect was observed,which seemed not to be mediated by soluble factors.

  11. Distinctive Profiles of Infection and Pathology in Hamsters Infected with Clostridium difficile Strains 630 and B1 ▿

    OpenAIRE

    Goulding, David; Thompson, Harold; Emerson, Jenny; Fairweather, Neil F.; Dougan, Gordon; Douce, Gill R.

    2009-01-01

    Currently, the Golden Syrian hamster is widely considered an important model of Clostridium difficile disease, as oral infection of this animal pretreated with antibiotics reproduces many of the symptoms observed in humans. Two C. difficile strains, B1 and 630, showed significant differences in the progression and severity of disease in this model. B1-infected hamsters exhibited more severe pathology and a shorter time to death than hamsters infected with 630. Histological changes in the gut ...

  12. Characterization of Syrian hamster adapted prions derived from L-type and C-type bovine spongiform encephalopathies

    OpenAIRE

    2011-01-01

    Atypical forms of bovine spongiform encephalopathy (BSE) may be caused by different prions from classical BSE (C-BSE). In this study, we examined the susceptibility of mice overexpressing mouse and hamster chimeric prion protein (PrP) to L-type atypical BSE (L-BSE). None of the transgenic mice showed susceptibility to L-BSE, except mice overexpressing hamster PrP. We also examined the transmission properties of L-BSE in hamsters. The incubation period of hamsters intracerebrally inoculated wi...

  13. All-trans retinoic acid enhances bystander effect of suicide gene therapy in the treatment of breast cancer.

    Science.gov (United States)

    Kong, Heng; Liu, Xia; Yang, Liucheng; Qi, Ke; Zhang, Haoyun; Zhang, Jingwen; Huang, Zonghai; Wang, Hongxian

    2016-03-01

    All-trans retinoic acid (ATRA) has been shown to enhance the expression of connexin 43 (Cx43) and the bystander effect (BSE) in suicide gene therapy. These in turn improve effects of suicide gene therapies for several tumor types. However, whether ATRA can improve BSE remains unclear in suicide gene therapy for breast cancer. In the present study, MCF-7, human breast cancer cells were treated with ATRA in combination with a VEGFP-TK/CD gene suicide system developed by our group. We found that this combination enhances the efficiency of cell killing and apoptosis of breast cancer by strengthening the BSE in vitro. ATRA also promotes gap junction intercellular communication (GJIC) in MCF-7 cells by upregulation of the connexin 43 mRNA and protein in MCF-7 cells. These results indicate that enhancement of GJIC by ATRA in suicide gene system might serve as an attractive and cost-effective strategy of therapy for breast cancer cells.

  14. LipL21 mRNA expression in lungs of hamsters infected with pathogenic Leptospira

    Institute of Scientific and Technical Information of China (English)

    Chintana Chirathaworn; Namo Suksomyos; Somchai Utivamek; Somboon Keelawat; Duangjai Suwancharoen; Duangporn Phulsuksombati; Yong Poovorawan

    2009-01-01

    Objective:Pulmonary haemorrhage is an increasing cause of death in leptospirosis patients.However,molecu-lar mechanism underlying pathologies in this organ is not clearly understood.It has been shown that sodium transport was disturbed following Leptospira infection.LipL21 is the second abundant outer membrane protein found only in pathogenic Leptospira.Its expression in vivo has been shown which suggests that this protein may be involved in survival in hosts or pathogenesis.However,the expression of this protein in host organs and its role in lung pathology has not been demonstrated.In this study we demonstrated the expression of LipL21 in lungs of hamsters infected with pathogenic Leptospira.Methods:Lung tissues were collected from Golden Syri-an hamsters injected with Leptospira interrogans serovar Pyrogenes at days 3,5 and 7 post-infection.Four ham-sters were used for each time point.Lungs from non-infected hamsters were collected as a control group.Li-pL21 mRNA expression in lung tissues was investigated by reverse transcription and nested PCR.Results:Li-pL21 mRNA expression was detected in all lung tissues from hamsters infected with pathogenic Leptospira.No PCR product was detected when tissues from non-infected hamsters were investigated.Conclusion:Our data demonstrated that LipL21 is expressed in lungs of hamsters infected with pathogenic Leptospira.Additional ex-periments such as quantitation and localization of LipL21 expression in lungs will provide further information whether this protein is involved in pathogenesis.

  15. DEVELOPMENT OF MICE AND HAMSTER EMBRYOS IN KSOMAA AND HECM-6 MEDIUM

    Directory of Open Access Journals (Sweden)

    Bayu Rosadi

    2008-12-01

    Full Text Available The purpose of the present study was to investigate the viability of mice and hamster embryos developed in Kalium Simplex Optimized Medium amino acid (KSOMaa and Hamster Embryo Culture Medium-6 (HECM-6 medium. Female DDY mice were superovulated by injection i.p. of 5 IU Pregnant Mare Serum Gonadotropine (PMSG and 5 IU Human Chorionic Gonadotropine (hCG in 48 h interval, hamster (Phodopus campbelli injected by 2.5 IU PMSG and 2.5 IU hCG 48 h later. Then females were mated with fertile males. Eight-cell embryos were recovered at day 3 after natural mating. The mice embryos were cultured in KSOMaa+5% NBCS (New Born Calf Serum (T1 and HECM-6+5% NBCS (T2, the hamster embryos were cultured in KSOMaa+5% NBCS (T3 and HECM-6 + 5% NBCS (T4 for further development at 37oC in a humidified atmosphere of 5% CO2 in air for 48 h. The examinations were replicated five times. The T1 embryos developed to compact morulla and early blastocyst 100% (140/140, 92.1% (129/140 to blastocyst and expanded blastocyst, and 22.9% (32/140 became hatching/hatched. The T3 reached 100% (60/60 to compact morulla and early blastocyst, 85.0% (51/60 blastocyst, and 48.3% (29/60 expanded blastocyst, no embryo observed hatching/hatced. The T2 embryos had more expanded blastocyst than T3 (P<0.05, hatching/hatched rate higher than T1 and T3 but lower than T4 (P<0.05. Shortly, KSOMaa enable to support 8-cell stage mice and hamster embryo, but the hamster embryo developed lower at expanded blastocyst stage. HECM-6 is more appropriate than KSOMaa to support 8-cell mice embryos development and suitable to develop 8-cell stage hamster embryos.

  16. Identification, expression, and physiological functions of Siberian hamster gonadotropin-inhibitory hormone.

    Science.gov (United States)

    Ubuka, Takayoshi; Inoue, Kazuhiko; Fukuda, Yujiro; Mizuno, Takanobu; Ukena, Kazuyoshi; Kriegsfeld, Lance J; Tsutsui, Kazuyoshi

    2012-01-01

    Gonadotropin-inhibitory hormone (GnIH) is a hypothalamic neuropeptide that inhibits gonadotropin secretion in birds and mammals. To further understand its physiological roles in mammalian reproduction, we identified its precursor cDNA and endogenous mature peptides in the Siberian hamster brain. The Siberian hamster GnIH precursor cDNA encoded two RFamide-related peptide (RFRP) sequences. SPAPANKVPHSAANLPLRF-NH(2) (Siberian hamster RFRP-1) and TLSRVPSLPQRF-NH(2) (Siberian hamster RFRP-3) were confirmed as mature endogenous peptides by mass spectrometry from brain samples purified by immunoaffinity chromatography. GnIH mRNA expression was higher in long days (LD) compared with short days (SD). GnIH mRNA was also highly expressed in SD plus pinealectomized animals, whereas expression was suppressed by melatonin, a nocturnal pineal hormone, administration. GnIH-immunoreactive (-ir) neurons were localized to the dorsomedial region of the hypothalamus, and GnIH-ir fibers projected to hypothalamic and limbic structures. The density of GnIH-ir perikarya and fibers were higher in LD and SD plus pinealectomized hamsters than in LD plus melatonin or SD animals. The percentage of GnRH neurons receiving close appositions from GnIH-ir fiber terminals was also higher in LD than SD, and GnIH receptor was expressed in GnRH-ir neurons. Finally, central administration of hamster RFRP-1 or RFRP-3 inhibited LH release 5 and 30 min after administration in LD. In sharp contrast, both peptides stimulated LH release 30 min after administration in SD. These results suggest that GnIH peptides fine tune LH levels via its receptor expressed in GnRH-ir neurons in an opposing fashion across the seasons in Siberian hamsters.

  17. Transmission of chronic wasting disease identifies a prion strain causing cachexia and heart infection in hamsters.

    Directory of Open Access Journals (Sweden)

    Richard A Bessen

    Full Text Available Chronic wasting disease (CWD is an emerging prion disease of free-ranging and captive cervids in North America. In this study we established a rodent model for CWD in Syrian golden hamsters that resemble key features of the disease in cervids including cachexia and infection of cardiac muscle. Following one to three serial passages of CWD from white-tailed deer into transgenic mice expressing the hamster prion protein gene, CWD was subsequently passaged into Syrian golden hamsters. In one passage line there were preclinical changes in locomotor activity and a loss of body mass prior to onset of subtle neurological symptoms around 340 days. The clinical symptoms included a prominent wasting disease, similar to cachexia, with a prolonged duration. Other features of CWD in hamsters that were similar to cervid CWD included the brain distribution of the disease-specific isoform of the prion protein, PrP(Sc, prion infection of the central and peripheral neuroendocrine system, and PrP(Sc deposition in cardiac muscle. There was also prominent PrP(Sc deposition in the nasal mucosa on the edge of the olfactory sensory epithelium with the lumen of the nasal airway that could have implications for CWD shedding into nasal secretions and disease transmission. Since the mechanism of wasting disease in prion diseases is unknown this hamster CWD model could provide a means to investigate the physiological basis of cachexia, which we propose is due to a prion-induced endocrinopathy. This prion disease phenotype has not been described in hamsters and we designate it as the 'wasting' or WST strain of hamster CWD.

  18. Teratogenic effects of mescaline, epinephrine, and norepinephrine in the hamster.

    Science.gov (United States)

    Hirsch, K S; Fritz, H I

    1981-06-01

    Mescaline was administered orally at doses of 16 and 32 mg/kg on the seventh through tenth days of gestation to pregnant cream-strain hamsters. This treatment resulted in a dose-dependent effect on reproductive success and skeletal ossification. The effect of mescaline on reproductive success included an increased number of resorptions resulting in a decreased litter size. The 32 mg/kg dose of mescaline caused 48.8% resorptions, while 16 mg/kg and control animals had 12.0% and 6.4% resorptions, respectively. Litter size was decreased from 12.0 pups in controls to 10.3 (16 mg/kg) and 6.5 (32 mg/kg) pups per litter in treated groups. No gross abnormalities were observed at necropsy; there was, however, a dose-dependent increased delay in the ossification of the skull, sternum, and metatarsals. Both epinephrine and norepinephrine caused a decrease in reproductive success when administered at 500 micrograms/kg. Epinephrine appeared to cause a trend toward preimplantation wastage as indicated by an increased corpora lutea to implantation site ratio (from 1.3-1.9). Norepinephrine, however, caused an increased number of resorptions (29.1% in controls). Both norepinephrine and epinephrine produced similar delays in ossification.

  19. Red Yeast Rice Increases Excretion of Bile Acids in Hamsters

    Institute of Scientific and Technical Information of China (English)

    KA-YING MA; ZE-SHENG ZHANG; SHU-XIN ZHAO; QI CHANG; YIN-MEI WONG; SAI YING VENUS YEUNG; YU HUANG; ZHEN-YU CHEN

    2009-01-01

    Objectives To investigate the hypocholesterolemic activity of red yeast rice (RYR) and its underlying mechanism. Methods Three groups of hamsters were fed either the control diet or one of the two experimental diets containing by weight 0.1% RYR (0.1RYR) or 0.3% RYR (0.3RYR). Blood (0.5 mL) was collected from the retro-orbital sinus into a heparinized capillary tube at the end of week 0,3, and 6.Plasma lipoproteins were measured using enzymatic kits, while fecal neutral and acidic sterols were quantified using a gas-liquid chromatography. Results Plasma total cholesterol was reduced by 12% in 0.1RYR group and by 18% in 0.3RYR group compared with the control value. Similarly, plasma triacylglycerol was decreased by ll% in 0.1RYR group and by 24% in 0.3RYR group. Western blotting analysis demonstrated that RYR had no effect on sterol regulatory element binding protein 2, liver X receptor, 3-hydroxy-3-methylglutary-CoA reductase, LDL receptor, and cholesterol-7α-hydroxylase. HPLC analysis confirmed that RYR contained 0.88% monacolin K.It was recently found that RYR supplementation increased excretion of fecal acidic sterols by 3-4 folds compared with the control value. Conclusion Hypocholesterolemic activity of RYR is mediated at least partially by enhancement of acidic sterol excretion.

  20. Oropouche virus experimental infection in the golden hamster (Mesocrisetus auratus).

    Science.gov (United States)

    Rodrigues, Alcir Humberto; Santos, Rodrigo Ivo; Arisi, Gabriel Maisonnave; Bernardes, Emerson Soares; Silva, Maria Lúcia; Rossi, Marcos Antônio; Lopes, Maria Beatriz Sampaio; Arruda, Eurico

    2011-01-01

    Oropouche virus (OROV), of the family Bunyaviridae, is the second most frequent arbovirus causing febrile disease in Brazil. In spite of this, little is known about pathogenesis of OROV infection. This report describes an experimental model of OROV in golden hamster (Mesocricetus auratus). Following subcutaneous inoculation of OROV, over 50% of the animals developed disease characterized by lethargy, ruffled fur, shivering, paralysis, and approximately one third died. Animals were sacrificed on days 1, 3, 5, 8 and 11 post-inoculation to collect tissue samples from brain, heart, liver, lung, spleen, muscle and blood for virus titration, histology and OROV immunohistochemistry. OROV was detected in high titers in blood, liver and brain, but not in the other organs. Histopathology revealed meningoencephalitis and hepatitis, with abundant OROV antigen detected in liver and brain. Diffuse galectin-3 immunostaining in brain and liver supports microglial and Kupfer cells activation. This is the first description of an experimental model for OROV infection and should be helpful to study pathogenesis and possibly to test antiviral interventions such as drugs and vaccine candidates.

  1. Radiation-induced emission from golden hamster embryo cells

    Science.gov (United States)

    Miyazaki, Tetsuo; Nagasaka, Shigeru; Maeda, Isao; Matsumoto, Takuro; Koyama, Shinji; Kodama, Seiji; Watanabe, Masami

    1996-06-01

    Emission from high-energy-electron-irradiated golden hamster embryo (GHE) cells has been studied over the temperature range 12-300 K both by a one-shot-single-photon-counting method and by photocurrent measurements with an oscilloscope. Emission from the irradiated phosphate buffered saline (PBS) also has been studied. The emission spectra from PBS at 12 and 77 K show a maximum around 330 and 380 nm, respectively, which are the same spectra as those from irradiated pure H 2O. The emission from irradiated GHE consists of the new band at 480 nm in addition to the emission from H 2O. The 480 nm emission is observed at the temperature range of 12-300 K, though the emission at 300 K is much lower than that at low temperature. The 480 nm emission is ascribed to the transition from excited organic substances in GHE cells. The intensity of 480 nm emission at 300 K increases linearly with increasing irradiation-dose in the range of 11-600 Gy.

  2. Chinese Dream

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    The general managers of South Korean auto giants Hyundai and Kia have high hopes for the growing Chinese auto market. Both companies went through a painstaking period as the financial crisis first roared across the globe. Jin Shan-fa, General Manager of Hyundai Motor Group

  3. The sz mutant hamster: a genetic model of epilepsy or of paroxysmal dystonia?

    Science.gov (United States)

    Löscher, W; Fisher, J E; Schmidt, D; Fredow, G; Hönack, D; Iturrian, W B

    1989-01-01

    Attacks of sustained dystonic postures of limbs and trunk can be initiated by mild environmental stimuli in an inbred line of Syrian hamsters. The trait is determined by an autosomal simple recessive genetic mutation, originally designated by the gene symbol sz, because the abnormal movements were thought to represent epileptic seizures. The attacks, which can be reproducibly initiated by placing the sz mutant hamsters in a new environment, begin with rapid twitches of the vibrissae, flattened ears, and flattened posture of the trunk while walking, followed by facial contortions, rearing, and sustained posturing of trunk and limbs, often resulting in falling over to the side or backwards. In the final stage, the hamsters became immobile, which can last for hours. An increased tone of limbs and trunk muscles can be palpated during the attack. Electromyographical recordings in awake, unrestrained mutant hamsters showed that the onset of the attack coincided with continuous tonic muscle activity and phasic bursts, which were present even when the animals did not move. During the attack, the animals continue to react to external stimuli. Bilateral electroencephalographic (EEG) recordings before and during motor disturbances in sz mutant hamsters showed no abnormalities. The severity of the dystonic syndrome in hamsters is age dependent with a peak at about 30-40 days of age. A score system for grading type and severity of dystonic attack was developed for use in drug activity studies. The severity of the attack was reduced or attacks were completely prevented by diazepam (1-2.5 mg/kg i.p.) and valproic acid (100-400 mg/kg i.p.) in a dose-dependent fashion. The latency to dystonic movements was significantly increased by diazepam but markedly reduced by subconvulsive doses of pentylenetetrazol (40 mg/kg s.c.). Diazepam antagonized the latency-reducing action of pentylenetetrazol in the hamsters. The pathophysiology and pharmacological sensitivity of the dystonic attacks

  4. HAMSTER: visualizing microarray experiments as a set of minimum spanning trees

    Directory of Open Access Journals (Sweden)

    Harada Hajime

    2009-11-01

    Full Text Available Abstract Background Visualization tools allow researchers to obtain a global view of the interrelationships between the probes or experiments of a gene expression (e.g. microarray data set. Some existing methods include hierarchical clustering and k-means. In recent years, others have proposed applying minimum spanning trees (MST for microarray clustering. Although MST-based clustering is formally equivalent to the dendrograms produced by hierarchical clustering under certain conditions; visually they can be quite different. Methods HAMSTER (Helpful Abstraction using Minimum Spanning Trees for Expression Relations is an open source system for generating a set of MSTs from the experiments of a microarray data set. While previous works have generated a single MST from a data set for data clustering, we recursively merge experiments and repeat this process to obtain a set of MSTs for data visualization. Depending on the parameters chosen, each tree is analogous to a snapshot of one step of the hierarchical clustering process. We scored and ranked these trees using one of three proposed schemes. HAMSTER is implemented in C++ and makes use of Graphviz for laying out each MST. Results We report on the running time of HAMSTER and demonstrate using data sets from the NCBI Gene Expression Omnibus (GEO that the images created by HAMSTER offer insights that differ from the dendrograms of hierarchical clustering. In addition to the C++ program which is available as open source, we also provided a web-based version (HAMSTER+ which allows users to apply our system through a web browser without any computer programming knowledge. Conclusion Researchers may find it helpful to include HAMSTER in their microarray analysis workflow as it can offer insights that differ from hierarchical clustering. We believe that HAMSTER would be useful for certain types of gradient data sets (e.g time-series data and data that indicate relationships between cells/tissues. Both

  5. Comparison of pulmonary and pleural responses of rats and hamsters to inhaled refractory ceramic fibers.

    Science.gov (United States)

    Gelzleichter, T R; Bermudez, E; Mangum, J B; Wong, B A; Janszen, D B; Moss, O R; Everitt, J I

    1999-05-01

    The present study was designed to determine whether pleural fiber burdens or subchronic pleural fibroproliferative and inflammatory changes can help explain the marked interspecies differences in pleural fibrosis and mesothelioma that are observed following long-term inhalation of RCF-1 ceramic fibers by rats and hamsters. Fischer 344 rats and Syrian golden hamsters were exposed to RCF-1 for 4 h per day, 5 days per week, for 12 consecutive weeks. Lung and pleural fiber burdens were characterized during and after exposure. For all time points, approximately 67% of fibers associated with lung tissues from both rats and hamsters were longer than 5 microns in length. In comparison, fibers longer than 5 microns recovered from the pleural compartment, following a 12-week exposure and 12 weeks of recovery, accounted for 13% (hamsters) and 4% (rats) of the distribution. In the 12 weeks after the cessation of exposure, the number of fibers longer than 5 microns in length remained constant in the hamster at approximately 150 fibers per cm2 pleura. This was 2 to 3 times the corresponding fiber surface density in the rat. Significant pulmonary and pleural inflammation was detected at all time points and for both species. DNA synthesis by pleural mesothelial cells was quantified by bromodeoxyuridine uptake following 3 days of labeling. Labeling indices were higher in hamsters than in rats, both for RCF-1-exposed and filtered air-control animals and was highest for the parietal surface of the pleura. Significantly greater collagen deposition was measured in the visceral pleura of hamsters 12 weeks post-exposure but was not significantly elevated in rats. These findings demonstrate that subchronic inhalation exposure to RCF-1 induces pleural inflammation, mesothelial-cell turnover, pleural fibrosis, and an accumulation of fibers with a length greater than 5 microns in the hamster. The accumulation of long fibers in the pleural space may contribute to the pathology observed in the

  6. Comparison of Pavlovian serial conditional discrimination in rats and hamsters in the same experimental situation

    Directory of Open Access Journals (Sweden)

    J.L.O. Bueno

    2001-12-01

    Full Text Available The present study compares behavioral changes between two distinct rodent groups, hamsters (Mesocricetus auratus and Wistar rats, when submitted in the same homogeneous experimental situations to a serial conditional discrimination procedure which involves water deprivation and the processing of temporal variables. Both hamsters and rats acquired serial positive conditional discrimination as indicated by higher frequencies of magazine-oriented behavior during the tone followed by reinforcement (T+ and preceded by the feature stimulus light (L and during the empty interval, than during the tone alone not followed by reinforcement (T-. Rats' frequencies