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Sample records for single rad52 repair

  1. Rad52 promotes second-end DNA capture in double-stranded break repair to form complement-stabilized joint molecules.

    PubMed

    Nimonkar, Amitabh V; Sica, R Alejandro; Kowalczykowski, Stephen C

    2009-03-01

    Saccharomyces cerevisiae Rad52 performs multiple functions during the recombinational repair of double-stranded DNA (dsDNA) breaks (DSBs). It mediates assembly of Rad51 onto single-stranded DNA (ssDNA) that is complexed with replication protein A (RPA); the resulting nucleoprotein filament pairs with homologous dsDNA to form joint molecules. Rad52 also catalyzes the annealing of complementary strands of ssDNA, even when they are complexed with RPA. Both Rad51 and Rad52 can be envisioned to promote "second-end capture," a step that pairs the ssDNA generated by processing of the second end of a DSB to the joint molecule formed by invasion of the target dsDNA by the first processed end. Here, we show that Rad52 promotes annealing of complementary ssDNA that is complexed with RPA to the displaced strand of a joint molecule, to form a complement-stabilized joint molecule. RecO, a prokaryotic homolog of Rad52, cannot form complement-stabilized joint molecules with RPA-ssDNA complexes, nor can Rad52 promote second-end capture when the ssDNA is bound with either human RPA or the prokaryotic ssDNA-binding protein, SSB, indicating a species-specific process. We conclude that Rad52 participates in second-end capture by annealing a resected DNA break, complexed with RPA, to the joint molecule product of single-end invasion event. These studies support a role for Rad52-promoted annealing in the formation of Holliday junctions in DSB repair. PMID:19204284

  2. Identification of Plant RAD52 Homologs and Characterization of the Arabidopsis thaliana RAD52-Like Genes[W

    PubMed Central

    Samach, Aviva; Melamed-Bessudo, Cathy; Avivi-Ragolski, Naomi; Pietrokovski, Shmuel; Levy, Avraham A.

    2011-01-01

    RADiation sensitive52 (RAD52) mediates RAD51 loading onto single-stranded DNA ends, thereby initiating homologous recombination and catalyzing DNA annealing. RAD52 is highly conserved among eukaryotes, including animals and fungi. This article reports that RAD52 homologs are present in all plants whose genomes have undergone extensive sequencing. Computational analyses suggest a very early RAD52 gene duplication, followed by later lineage-specific duplications, during the evolution of higher plants. Plant RAD52 proteins have high sequence similarity to the oligomerization and DNA binding N-terminal domain of RAD52 proteins. Remarkably, the two identified Arabidopsis thaliana RAD52 genes encode four open reading frames (ORFs) through differential splicing, each of which specifically localized to the nucleus, mitochondria, or chloroplast. The A. thaliana RAD52-1A ORF provided partial complementation to the yeast rad52 mutant. A. thaliana mutants and RNA interference lines defective in the expression of RAD52-1 or RAD52-2 showed reduced fertility, sensitivity to mitomycin C, and decreased levels of intrachromosomal recombination compared with the wild type. In summary, computational and experimental analyses provide clear evidence for the presence of functional RAD52 DNA-repair homologs in plants. PMID:22202891

  3. An allele of RFA1 suppresses RAD52-dependent double-strand break repair in Saccharomyces cerevisiae.

    PubMed Central

    Smith, J; Rothstein, R

    1999-01-01

    An allele of RFA1, the largest subunit of the single-stranded DNA-binding complex RP-A, was identified as a suppressor of decreased direct-repeat recombination in rad1 rad52 double mutants. In this study, we used two LEU2 direct-repeat assays to investigate the mechanism by which the rfa1-D228Y allele increases recombination. We found that both intrachromatid and sister chromatid recombination are stimulated in rfa1-D228Y strains. In a rad1 rad52 background, however, the majority of the increased recombination is caused by stimulation of deletion events by an intrachromatid recombination mechanism that is likely to be single-strand annealing. Studies in which an HO endonuclease cut was introduced between the two leu2 copies indicate that the rfa1-D228Y mutation partially suppresses the rad52 defect in recovering recombination products. Furthermore, molecular analysis of processing and product formation kinetics reveals that, in a rad52 background, the rfa1-D228Y mutation results in increased levels of recombinant products and the disappearance of large single-stranded intermediates characteristic of rad52 strains. On the basis of these results, we propose that in the absence of wild-type Rad52, the interaction of RP-A with single-stranded DNA inhibits strand annealing, and that this inhibition is overcome by the rfa1-D228Y mutation. PMID:9927442

  4. Two DNA repair and recombination genes in Saccharomyces cerevisiae, RAD52 and RAD54, are induced during meiosis

    SciTech Connect

    Cole, G.M.; Mortimer, R.K. ); Schild, D. )

    1989-07-01

    The DNA repair and recombination genes of Saccharomyces cerevisiae, RAD52 and RAD54, were transcriptionally induced approximately 10- to 15-fold in sporulating MATa/{alpha} cells. Congenic MATa/a cells, which did not sporulate, did not show similar increases. Assays of {beta}-galactosidase activity in strains harboring either a RAD52- or RAD54-lacZ gene fusion indicated that this induction occurred at a time concomitant with a commitment to meiotic recombination, as measured by prototroph formation from his1 heteroalleles.

  5. Multiple Rad52-Mediated Homology-Directed Repair Mechanisms Are Required to Prevent Telomere Attrition-Induced Senescence in Saccharomyces cerevisiae

    PubMed Central

    2016-01-01

    Most human somatic cells express insufficient levels of telomerase, which can result in telomere shortening and eventually senescence, both of which are hallmarks of ageing. Homology-directed repair (HDR) is important for maintaining proper telomere function in yeast and mammals. In Saccharomyces cerevisiae, Rad52 is required for almost all HDR mechanisms, and telomerase-null cells senesce faster in the absence of Rad52. However, its role in preventing accelerated senescence has been unclear. In this study, we make use of rad52 separation-of-function mutants to find that multiple Rad52-mediated HDR mechanisms are required to delay senescence, including break-induced replication and sister chromatid recombination. In addition, we show that misregulation of histone 3 lysine 56 acetylation, which is known to be defective in sister chromatid recombination, also causes accelerated senescence. We propose a model where Rad52 is needed to repair telomere attrition-induced replication stress. PMID:27428329

  6. Classification and evolutionary history of the single-strand annealing proteins, RecT, Redβ, ERF and RAD52

    PubMed Central

    Iyer, Lakshminarayan M; Koonin, Eugene V; Aravind, L

    2002-01-01

    Background The DNA single-strand annealing proteins (SSAPs), such as RecT, Redβ, ERF and Rad52, function in RecA-dependent and RecA-independent DNA recombination pathways. Recently, they have been shown to form similar helical quaternary superstructures. However, despite the functional similarities between these diverse SSAPs, their actual evolutionary affinities are poorly understood. Results Using sensitive computational sequence analysis, we show that the RecT and Redβ proteins, along with several other bacterial proteins, form a distinct superfamily. The ERF and Rad52 families show no direct evolutionary relationship to these proteins and define novel superfamilies of their own. We identify several previously unknown members of each of these superfamilies and also report, for the first time, bacterial and viral homologs of Rad52. Additionally, we predict the presence of aberrant HhH modules in RAD52 that are likely to be involved in DNA-binding. Using the contextual information obtained from the analysis of gene neighborhoods, we provide evidence of the interaction of the bacterial members of each of these SSAP superfamilies with a similar set of DNA repair/recombination protein. These include different nucleases or Holliday junction resolvases, the ABC ATPase SbcC and the single-strand-binding protein. We also present evidence of independent assembly of some of the predicted operons encoding SSAPs and in situ displacement of functionally similar genes. Conclusions There are three evolutionarily distinct superfamilies of SSAPs, namely the RecT/Redβ, ERF, and RAD52, that have different sequence conservation patterns and predicted folds. All these SSAPs appear to be primarily of bacteriophage origin and have been acquired by numerous phylogenetically distant cellular genomes. They generally occur in predicted operons encoding one or more of a set of conserved DNA recombination proteins that appear to be the principal functional partners of the SSAPs. PMID

  7. Tyrosine phosphorylation enhances RAD52-mediated annealing by modulating its DNA binding

    PubMed Central

    Honda, Masayoshi; Okuno, Yusuke; Yoo, Jungmin; Ha, Taekjip; Spies, Maria

    2011-01-01

    RAD52 protein has an important role in homology-directed DNA repair by mediating RAD51 nucleoprotein filament formation on single-stranded DNA (ssDNA) protected by replication protein-A (RPA) and annealing of RPA-coated ssDNA. In human, cellular response to DNA damage includes phosphorylation of RAD52 by c-ABL kinase at tyrosine 104. To address how this phosphorylation modulates RAD52 function, we used an amber suppressor technology to substitute tyrosine 104 with chemically stable phosphotyrosine analogue (p-Carboxymethyl-L-phenylalanine, pCMF). The RAD52Y104pCMF retained ssDNA-binding activity characteristic of unmodified RAD52 but showed lower affinity for double-stranded DNA (dsDNA) binding. Single-molecule analyses revealed that RAD52Y104pCMF specifically targets and wraps ssDNA. While RAD52Y104pCMF is confined to ssDNA region, unmodified RAD52 readily diffuses into dsDNA region. The Y104pCMF substitution also increased the ssDNA annealing rate and allowed overcoming the inhibitory effect of dsDNA. We propose that phosphorylation at Y104 enhances ssDNA annealing activity of RAD52 by attenuating dsDNA binding. Implications of phosphorylation-mediated activation of RAD52 annealing activity are discussed. PMID:21804533

  8. Recruitment Kinetics of DNA Repair Proteins Mdc1 and Rad52 but Not 53BP1 Depend on Damage Complexity

    PubMed Central

    Hable, Volker; Drexler, Guido A.; Brüning, Tino; Burgdorf, Christian; Greubel, Christoph; Derer, Anja; Seel, Judith; Strickfaden, Hilmar; Cremer, Thomas; Friedl, Anna A.; Dollinger, Günther

    2012-01-01

    The recruitment kinetics of double-strand break (DSB) signaling and repair proteins Mdc1, 53BP1 and Rad52 into radiation-induced foci was studied by live-cell fluorescence microscopy after ion microirradiation. To investigate the influence of damage density and complexity on recruitment kinetics, which cannot be done by UV laser irradiation used in former studies, we utilized 43 MeV carbon ions with high linear energy transfer per ion (LET = 370 keV/µm) to create a large fraction of clustered DSBs, thus forming complex DNA damage, and 20 MeV protons with low LET (LET  = 2.6 keV/µm) to create mainly isolated DSBs. Kinetics for all three proteins was characterized by a time lag period T0 after irradiation, during which no foci are formed. Subsequently, the proteins accumulate into foci with characteristic mean recruitment times τ1. Mdc1 accumulates faster (T0 = 17±2 s, τ1 = 98±11 s) than 53BP1 (T0 = 77±7 s, τ1 = 310±60 s) after high LET irradiation. However, recruitment of Mdc1 slows down (T0 = 73±16 s, τ1 = 1050±270 s) after low LET irradiation. The recruitment kinetics of Rad52 is slower than that of Mdc1, but exhibits the same dependence on LET. In contrast, the mean recruitment time τ1 of 53BP1 remains almost constant when varying LET. Comparison to literature data on Mdc1 recruitment after UV laser irradiation shows that this rather resembles recruitment after high than low LET ionizing radiation. So this work shows that damage quality has a large influence on repair processes and has to be considered when comparing different studies. PMID:22860035

  9. Mating-type suppression of the DNA-repair defect of the yeast rad6 delta mutation requires the activity of genes in the RAD52 epistasis group.

    PubMed

    Yan, Y X; Schiestl, R H; Prakash, L

    1995-06-01

    The RAD6 gene of Saccharomyces cerevisiae is required for post-replication repair of UV-damaged DNA, UV mutagenesis, and sporulation. Here, we show that the radiation sensitivity of a MATa rad6 delta strain can be suppressed by the MAT alpha 2 gene carried on a multicopy plasmid. The a1-alpha 2 suppression is specific to the RAD6 pathway, as mutations in genes required for nucleotide excision repair or for recombinational repair do not show such mating-type suppression. The a1-alpha 2 suppression of the rad6 delta mutation requires the activity of the RAD52 group of genes, suggesting that suppression occurs by channelling of post-replication gaps present in the rad6 delta mutant into the RAD52 recombinational repair pathway. The a1-alpha 2 repressor could mediate this suppression via an enhancement in the expression, or the activity, of recombination genes.

  10. Biochemical characterization of plant Rad52 protein from rice (Oryza sativa).

    PubMed

    Nair, Anuradha; Agarwal, Rachna; Chittela, Rajani Kant

    2016-09-01

    DNA damage in living cells is repaired by two main pathways, homologous recombination (HR) and non-homologous end joining (NHEJ). Of all the genes promoting HR, Rad52 (Radiation sensitive 52) is an important gene which is found to be highly conserved across different species. It was believed that RAD52 is absent in plant systems until lately. However, recent genetic studies have shown the presence of RAD52 homologues in plants. Rad52 homologues in plant systems have not yet been characterized biochemically. In the current study, we bring out the biochemical properties of rice Rad52-2a protein. OsRad52-2a was over-expressed in Escherichia coli BL21 (DE3) cells and the protein was purified. The identity of purified OsRad52-2a protein was confirmed via peptide mass fingerprinting. Gel filtration and native PAGE analysis indicated that the OsRad52-2a protein in its native state probably formed an undecameric structure. Purified OsRad52-2a protein showed binding to single stranded DNA, double stranded DNA. Protein also mediated the renaturation of complementary single strands into duplex DNA in both agarose gel and FRET based assays. Put together, OsRad52-2a forms oligomeric structures and binds to ssDNA/dsDNA for mediating an important function like renaturation during homologous recombination. This study represents the first report on biochemical properties of OsRad52-2a protein from important crop like rice. This information will help in dissecting the recombination and repair machinery in plant systems. PMID:27156135

  11. Targeting BRCA1- and BRCA2-deficient cells with RAD52 small molecule inhibitors.

    PubMed

    Huang, Fei; Goyal, Nadish; Sullivan, Katherine; Hanamshet, Kritika; Patel, Mikir; Mazina, Olga M; Wang, Charles X; An, W Frank; Spoonamore, James; Metkar, Shailesh; Emmitte, Kyle A; Cocklin, Simon; Skorski, Tomasz; Mazin, Alexander V

    2016-05-19

    RAD52 is a member of the homologous recombination (HR) pathway that is important for maintenance of genome integrity. While single RAD52 mutations show no significant phenotype in mammals, their combination with mutations in genes that cause hereditary breast cancer and ovarian cancer like BRCA1, BRCA2, PALB2 and RAD51C are lethal. Consequently, RAD52 may represent an important target for cancer therapy. In vitro, RAD52 has ssDNA annealing and DNA strand exchange activities. Here, to identify small molecule inhibitors of RAD52 we screened a 372,903-compound library using a fluorescence-quenching assay for ssDNA annealing activity of RAD52. The obtained 70 putative inhibitors were further characterized using biochemical and cell-based assays. As a result, we identified compounds that specifically inhibit the biochemical activities of RAD52, suppress growth of BRCA1- and BRCA2-deficient cells and inhibit RAD52-dependent single-strand annealing (SSA) in human cells. We will use these compounds for development of novel cancer therapy and as a probe to study mechanisms of DNA repair. PMID:26873923

  12. Complex formation in yeast double-strand break repair: participation of Rad51, Rad52, Rad55, and Rad57 proteins.

    PubMed Central

    Hays, S L; Firmenich, A A; Berg, P

    1995-01-01

    The repair of DNA double-strand breaks in Saccharomyces cerevisiae requires genes of the RAD52 epistasis group, of which RAD55 and RAD57 are members. Here, we show that the x-ray sensitivity of rad55 and rad57 mutant strains is suppressible by overexpression of RAD51 or RAD52. Virtually complete suppression is provided by the simultaneous overexpression of RAD51 and RAD52. This suppression occurs at 23 degrees C, where these mutants are more sensitive to x-rays, as well as at 30 degrees C and 36 degrees C. In addition, a recombination defect of rad55 and rad57 mutants is similarly suppressed. Direct in vivo interactions between the Rad51 and Rad55 proteins, and between Rad55 and Rad57, have also been identified by using the two-hybrid system. These results indicate that these four proteins constitute part of a complex, a "recombinosome," to effect the recombinational repair of double-strand breaks. PMID:7624345

  13. Members of the RAD52 Epistasis Group Contribute to Mitochondrial Homologous Recombination and Double-Strand Break Repair in Saccharomyces cerevisiae.

    PubMed

    Stein, Alexis; Kalifa, Lidza; Sia, Elaine A

    2015-11-01

    Mitochondria contain an independently maintained genome that encodes several proteins required for cellular respiration. Deletions in the mitochondrial genome have been identified that cause several maternally inherited diseases and are associated with certain cancers and neurological disorders. The majority of these deletions in human cells are flanked by short, repetitive sequences, suggesting that these deletions may result from recombination events. Our current understanding of the maintenance and repair of mtDNA is quite limited compared to our understanding of similar events in the nucleus. Many nuclear DNA repair proteins are now known to also localize to mitochondria, but their function and the mechanism of their action remain largely unknown. This study investigated the contribution of the nuclear double-strand break repair (DSBR) proteins Rad51p, Rad52p and Rad59p in mtDNA repair. We have determined that both Rad51p and Rad59p are localized to the matrix of the mitochondria and that Rad51p binds directly to mitochondrial DNA. In addition, a mitochondrially-targeted restriction endonuclease (mtLS-KpnI) was used to produce a unique double-strand break (DSB) in the mitochondrial genome, which allowed direct analysis of DSB repair in vivo in Saccharomyces cerevisiae. We find that loss of these three proteins significantly decreases the rate of spontaneous deletion events and the loss of Rad51p and Rad59p impairs the repair of induced mtDNA DSBs.

  14. Reappearance from Obscurity: Mammalian Rad52 in Homologous Recombination

    PubMed Central

    Hanamshet, Kritika; Mazina, Olga M.; Mazin, Alexander V.

    2016-01-01

    Homologous recombination (HR) plays an important role in maintaining genomic integrity. It is responsible for repair of the most harmful DNA lesions, DNA double-strand breaks and inter-strand DNA cross-links. HR function is also essential for proper segregation of homologous chromosomes in meiosis, maintenance of telomeres, and resolving stalled replication forks. Defects in HR often lead to genetic diseases and cancer. Rad52 is one of the key HR proteins, which is evolutionarily conserved from yeast to humans. In yeast, Rad52 is important for most HR events; Rad52 mutations disrupt repair of DNA double-strand breaks and targeted DNA integration. Surprisingly, in mammals, Rad52 knockouts showed no significant DNA repair or recombination phenotype. However, recent work demonstrated that mutations in human RAD52 are synthetically lethal with mutations in several other HR proteins including BRCA1 and BRCA2. These new findings indicate an important backup role for Rad52, which complements the main HR mechanism in mammals. In this review, we focus on the Rad52 activities and functions in HR and the possibility of using human RAD52 as therapeutic target in BRCA1 and BRCA2-deficient familial breast cancer and ovarian cancer. PMID:27649245

  15. Reappearance from Obscurity: Mammalian Rad52 in Homologous Recombination.

    PubMed

    Hanamshet, Kritika; Mazina, Olga M; Mazin, Alexander V

    2016-01-01

    Homologous recombination (HR) plays an important role in maintaining genomic integrity. It is responsible for repair of the most harmful DNA lesions, DNA double-strand breaks and inter-strand DNA cross-links. HR function is also essential for proper segregation of homologous chromosomes in meiosis, maintenance of telomeres, and resolving stalled replication forks. Defects in HR often lead to genetic diseases and cancer. Rad52 is one of the key HR proteins, which is evolutionarily conserved from yeast to humans. In yeast, Rad52 is important for most HR events; Rad52 mutations disrupt repair of DNA double-strand breaks and targeted DNA integration. Surprisingly, in mammals, Rad52 knockouts showed no significant DNA repair or recombination phenotype. However, recent work demonstrated that mutations in human RAD52 are synthetically lethal with mutations in several other HR proteins including BRCA1 and BRCA2. These new findings indicate an important backup role for Rad52, which complements the main HR mechanism in mammals. In this review, we focus on the Rad52 activities and functions in HR and the possibility of using human RAD52 as therapeutic target in BRCA1 and BRCA2-deficient familial breast cancer and ovarian cancer. PMID:27649245

  16. The C-terminal region of Rad52 is essential for Rad52 nuclear and nucleolar localization, and accumulation at DNA damage sites immediately after irradiation

    SciTech Connect

    Koike, Manabu; Yutoku, Yasutomo; Koike, Aki

    2013-05-31

    Highlights: •Rad52 might play a key role in the repair of DSB immediately after irradiation. •EYFP-Rad52 accumulates rapidly at DSB sites and colocalizes with Ku80. •Accumulation of Rad52 at DSB sites is independent of the core NHEJ factors. •Localization and recruitment of Rad52 to DSB sites are dependent on the Rad52 CTR. •Basic amino acids in Rad52 CTR are highly conserved among vertebrate species. -- Abstract: Rad52 plays essential roles in homologous recombination (HR) and repair of DNA double-strand breaks (DSBs) in Saccharomyces cerevisiae. However, in vertebrates, knockouts of the Rad52 gene show no hypersensitivity to agents that induce DSBs. Rad52 localizes in the nucleus and forms foci at a late stage following irradiation. Ku70 and Ku80, which play an essential role in nonhomologous DNA-end-joining (NHEJ), are essential for the accumulation of other core NHEJ factors, e.g., XRCC4, and a HR-related factor, e.g., BRCA1. Here, we show that the subcellular localization of EYFP-Rad52(1–418) changes dynamically during the cell cycle. In addition, EYFP-Rad52(1–418) accumulates rapidly at microirradiated sites and colocalizes with the DSB sensor protein Ku80. Moreover, the accumulation of EYFP-Rad52(1–418) at DSB sites is independent of the core NHEJ factors, i.e., Ku80 and XRCC4. Furthermore, we observed that EYFP-Rad52(1–418) localizes in nucleoli in CHO-K1 cells and XRCC4-deficient cells, but not in Ku80-deficient cells. We also found that Rad52 nuclear localization, nucleolar localization, and accumulation at DSB sites are dependent on eight amino acids (411–418) at the end of the C-terminal region of Rad52 (Rad52 CTR). Furthermore, basic amino acids on Rad52 CTR are highly conserved among mammalian, avian, and fish homologues, suggesting that Rad52 CTR is important for the regulation and function of Rad52 in vertebrates. These findings also suggest that the mechanism underlying the regulation of subcellular localization of Rad52 is

  17. A Saccharomyces Cerevisiae Rad52 Allele Expressing a C-Terminal Truncation Protein: Activities and Intragenic Complementation of Missense Mutations

    PubMed Central

    Boundy-Mills, K. L.; Livingston, D. M.

    1993-01-01

    A nonsense allele of the yeast RAD52 gene, rad52-327, which expresses the N-terminal 65% of the protein was compared to two missense alleles, rad52-1 and rad52-2, and to a deletion allele. While the rad52-1 and the deletion mutants have severe defects in DNA repair, recombination and sporulation, the rad52-327 and rad52-2 mutants retain either partial or complete capabilities in repair and recombination. These two mutants behave similarly in most tests of repair and recombination during mitotic growth. One difference between these two alleles is that a homozygous rad52-2 diploid fails to sporulate, whereas the homozygous rad52-327 diploid sporulates weakly. The low level of sporulation by the rad52-327 diploid is accompanied by a low percentage of spore viability. Among these viable spores the frequency of crossing over for markers along chromosome VII is the same as that found in wild-type spores. rad52-327 complements rad52-2 for repair and sporulation. Weaker intragenic complementation occurs between rad52-327 and rad52-1. PMID:8417987

  18. Different mating-type-regulated genes affect the DNA repair defects of Saccharomyces RAD51, RAD52 and RAD55 mutants.

    PubMed

    Valencia-Burton, Maria; Oki, Masaya; Johnson, Jean; Seier, Tracey A; Kamakaka, Rohinton; Haber, James E

    2006-09-01

    Saccharomyces cerevisiae cells expressing both a- and alpha-mating-type (MAT) genes (termed mating-type heterozygosity) exhibit higher rates of spontaneous recombination and greater radiation resistance than cells expressing only MATa or MATalpha. MAT heterozygosity suppresses recombination defects of four mutations involved in homologous recombination: complete deletions of RAD55 or RAD57, an ATPase-defective Rad51 mutation (rad51-K191R), and a C-terminal truncation of Rad52, rad52-Delta327. We investigated the genetic basis of MAT-dependent suppression of these mutants by deleting genes whose expression is controlled by the Mata1-Matalpha2 repressor and scoring resistance to both campothecin (CPT) and phleomycin. Haploid rad55Delta strains became more damage resistant after deleting genes required for nonhomologous end-joining (NHEJ), a process that is repressed in MATa/MATalpha cells. Surprisingly, NHEJ mutations do not suppress CPT sensitivity of rad51-K191R or rad52-Delta327. However, rad51-K191R is uniquely suppressed by deleting the RME1 gene encoding a repressor of meiosis or its coregulator SIN4; this effect is independent of the meiosis-specific homolog, Dmc1. Sensitivity of rad52-Delta327 to CPT was unexpectedly increased by the MATa/MATalpha-repressed gene YGL193C, emphasizing the complex ways in which MAT regulates homologous recombination. The rad52-Delta327 mutation is suppressed by deleting the prolyl isomerase Fpr3, which is not MAT regulated. rad55Delta is also suppressed by deletion of PST2 and/or YBR052C (RFS1, rad55 suppressor), two members of a three-gene family of flavodoxin-fold proteins that associate in a nonrandom fashion with chromatin. All three recombination-defective mutations are made more sensitive by deletions of Rad6 and of the histone deacetylases Rpd3 and Ume6, although these mutations are not themselves CPT or phleomycin sensitive.

  19. Personalized synthetic lethality induced by targeting RAD52 in leukemias identified by gene mutation and expression profile

    PubMed Central

    Cramer-Morales, Kimberly; Nieborowska-Skorska, Margaret; Scheibner, Kara; Padget, Michelle; Irvine, David A.; Sliwinski, Tomasz; Haas, Kimberly; Lee, Jaewoong; Geng, Huimin; Roy, Darshan; Slupianek, Artur; Rassool, Feyruz V.; Wasik, Mariusz A.; Childers, Wayne; Copland, Mhairi; Müschen, Markus; Civin, Curt I.

    2013-01-01

    Homologous recombination repair (HRR) protects cells from the lethal effect of spontaneous and therapy-induced DNA double-stand breaks. HRR usually depends on BRCA1/2-RAD51, and RAD52-RAD51 serves as back-up. To target HRR in tumor cells, a phenomenon called “synthetic lethality” was applied, which relies on the addiction of cancer cells to a single DNA repair pathway, whereas normal cells operate 2 or more mechanisms. Using mutagenesis and a peptide aptamer approach, we pinpointed phenylalanine 79 in RAD52 DNA binding domain I (RAD52-phenylalanine 79 [F79]) as a valid target to induce synthetic lethality in BRCA1- and/or BRCA2-deficient leukemias and carcinomas without affecting normal cells and tissues. Targeting RAD52-F79 disrupts the RAD52–DNA interaction, resulting in the accumulation of toxic DNA double-stand breaks in malignant cells, but not in normal counterparts. In addition, abrogation of RAD52–DNA interaction enhanced the antileukemia effect of already-approved drugs. BRCA-deficient status predisposing to RAD52-dependent synthetic lethality could be predicted by genetic abnormalities such as oncogenes BCR-ABL1 and PML-RAR, mutations in BRCA1 and/or BRCA2 genes, and gene expression profiles identifying leukemias displaying low levels of BRCA1 and/or BRCA2. We believe this work may initiate a personalized therapeutic approach in numerous patients with tumors displaying encoded and functional BRCA deficiency. PMID:23836560

  20. A core activity associated with the N terminus of the yeast RAD52 protein is revealed by RAD51 overexpression suppression of C-terminal rad52 truncation alleles.

    PubMed Central

    Asleson, E N; Okagaki, R J; Livingston, D M

    1999-01-01

    C-terminal rad52 truncation and internal deletion mutants were characterized for their ability to repair MMS-induced double-strand breaks and to produce viable spores during meiosis. The rad52-Delta251 allele, encoding the N-terminal 251 amino acids of the predicted 504-amino-acid polypeptide, supports partial activity for both functions. Furthermore, RAD51 overexpression completely suppresses the MMS sensitivity of a rad52-Delta251 mutant. The absence of the C terminus in the truncated protein makes it likely that suppression occurs by bypassing the C-terminal functions of Rad52p. RAD51 overexpression does not suppress the low level of spore viability that the rad52-Delta251 allele causes and only partially suppresses the defect in rad52 alleles encoding the N-terminal 292 or 327 amino acids. The results of this study also show that intragenic complementation between rad52 alleles is governed by a complex relationship that depends heavily on the two alleles involved and their relative dosage. In heteroallelic rad52 diploids, the rad52-Delta251 allele does not complement rad52 missense mutations altering residues 61 or 64 in the N terminus. However, complementation is achieved with each of these missense alleles when the rad52-Delta251 allele is overexpressed. Complementation also occurs between rad52-Delta327 and an internal deletion allele missing residues 210 through 327. We suggest that the first 251 amino acids of Rad52p constitute a core domain that provides critical RAD52 activities. PMID:10511548

  1. Roles of C-Terminal Region of Yeast and Human Rad52 in Rad51-Nucleoprotein Filament Formation and ssDNA Annealing

    PubMed Central

    Khade, Nilesh V.; Sugiyama, Tomohiko

    2016-01-01

    Yeast Rad52 (yRad52) has two important functions at homologous DNA recombination (HR); annealing complementary single-strand DNA (ssDNA) molecules and recruiting Rad51 recombinase onto ssDNA (recombination mediator activity). Its human homolog (hRAD52) has a lesser role in HR, and apparently lacks mediator activity. Here we show that yRad52 can load human Rad51 (hRAD51) onto ssDNA complexed with yeast RPA in vitro. This is biochemically equivalent to mediator activity because it depends on the C-terminal Rad51-binding region of yRad52 and on functional Rad52-RPA interaction. It has been reported that the N-terminal two thirds of both yRad52 and hRAD52 is essential for binding to and annealing ssDNA. Although a second DNA binding region has been found in the C-terminal region of yRad52, its role in ssDNA annealing is not clear. In this paper, we also show that the C-terminal region of yRad52, but not of hRAD52, is involved in ssDNA annealing. This suggests that the second DNA binding site is required for the efficient ssDNA annealing by yRad52. We propose an updated model of Rad52-mediated ssDNA annealing. PMID:27362509

  2. Small-molecule inhibitors identify the RAD52-ssDNA interaction as critical for recovery from replication stress and for survival of BRCA2 deficient cells

    PubMed Central

    Hengel, Sarah R; Malacaria, Eva; Folly da Silva Constantino, Laura; Bain, Fletcher E; Diaz, Andrea; Koch, Brandon G; Yu, Liping; Wu, Meng; Pichierri, Pietro; Spies, M Ashley; Spies, Maria

    2016-01-01

    The DNA repair protein RAD52 is an emerging therapeutic target of high importance for BRCA-deficient tumors. Depletion of RAD52 is synthetically lethal with defects in tumor suppressors BRCA1, BRCA2 and PALB2. RAD52 also participates in the recovery of the stalled replication forks. Anticipating that ssDNA binding activity underlies the RAD52 cellular functions, we carried out a high throughput screening campaign to identify compounds that disrupt the RAD52-ssDNA interaction. Lead compounds were confirmed as RAD52 inhibitors in biochemical assays. Computational analysis predicted that these inhibitors bind within the ssDNA-binding groove of the RAD52 oligomeric ring. The nature of the inhibitor-RAD52 complex was validated through an in silico screening campaign, culminating in the discovery of an additional RAD52 inhibitor. Cellular studies with our inhibitors showed that the RAD52-ssDNA interaction enables its function at stalled replication forks, and that the inhibition of RAD52-ssDNA binding acts additively with BRCA2 or MUS81 depletion in cell killing. DOI: http://dx.doi.org/10.7554/eLife.14740.001 PMID:27434671

  3. Small-molecule inhibitors identify the RAD52-ssDNA interaction as critical for recovery from replication stress and for survival of BRCA2 deficient cells.

    PubMed

    Hengel, Sarah R; Malacaria, Eva; Folly da Silva Constantino, Laura; Bain, Fletcher E; Diaz, Andrea; Koch, Brandon G; Yu, Liping; Wu, Meng; Pichierri, Pietro; Spies, M Ashley; Spies, Maria

    2016-01-01

    The DNA repair protein RAD52 is an emerging therapeutic target of high importance for BRCA-deficient tumors. Depletion of RAD52 is synthetically lethal with defects in tumor suppressors BRCA1, BRCA2 and PALB2. RAD52 also participates in the recovery of the stalled replication forks. Anticipating that ssDNA binding activity underlies the RAD52 cellular functions, we carried out a high throughput screening campaign to identify compounds that disrupt the RAD52-ssDNA interaction. Lead compounds were confirmed as RAD52 inhibitors in biochemical assays. Computational analysis predicted that these inhibitors bind within the ssDNA-binding groove of the RAD52 oligomeric ring. The nature of the inhibitor-RAD52 complex was validated through an in silico screening campaign, culminating in the discovery of an additional RAD52 inhibitor. Cellular studies with our inhibitors showed that the RAD52-ssDNA interaction enables its function at stalled replication forks, and that the inhibition of RAD52-ssDNA binding acts additively with BRCA2 or MUS81 depletion in cell killing. PMID:27434671

  4. Associations of UBE2I with RAD52, UBL1, p53, and RAD51 proteins in a yeast two-hybrid system

    SciTech Connect

    Shen, Zhiyuan; Pardington-Purtymun, P.E.; Comeaux, J.C.

    1996-10-15

    The yeast RAD52-dependent pathway is involved in DNA recombination and double-strand break repair. Yeast ubiquitin-conjugating enzyme UBC9 participates in S- and M-phase cyclin degradation and mitotic control. Using the human RAD52 protein as the bait in a yeast two-hybrid system, we have identified a human homolog of yeast UBC9, designated UBE2I, that interacts with RAD52, RAD51, p53, and a ubiquitin-like protein UBL1. These interactions are UBE2I-specific, since another DNA repair-related ubiquitin-conjugating enzyme, RAD6 (UBC2), does not interact with these proteins. The interaction of UBE2I with RAD52 is mediated by RAD52`s self-association region. These results suggest that the RAD52-dependent processes, cell cycle control, p53-mediated pathway(s), and ubiquitination interact through human UBE2I. 22 refs., 3 figs.

  5. Rad52-mediated DNA annealing after Rad51-mediated DNA strand exchange promotes second ssDNA capture.

    PubMed

    Sugiyama, Tomohiko; Kantake, Noriko; Wu, Yun; Kowalczykowski, Stephen C

    2006-11-29

    Rad51, Rad52, and RPA play central roles in homologous DNA recombination. Rad51 mediates DNA strand exchange, a key reaction in DNA recombination. Rad52 has two distinct activities: to recruit Rad51 onto single-strand (ss)DNA that is complexed with the ssDNA-binding protein, RPA, and to anneal complementary ssDNA complexed with RPA. Here, we report that Rad52 promotes annealing of the ssDNA strand that is displaced by DNA strand exchange by Rad51 and RPA, to a second ssDNA strand. An RPA that is recombination-deficient (RPA(rfa1-t11)) failed to support annealing, explaining its in vivo phenotype. Escherichia coli RecO and SSB proteins, which are functional homologues of Rad52 and RPA, also facilitated the same reaction, demonstrating its conserved nature. We also demonstrate that the two activities of Rad52, recruiting Rad51 and annealing DNA, are coordinated in DNA strand exchange and second ssDNA capture. PMID:17093500

  6. A molecular beacon approach to detecting RAD52 expression in response to DNA damage in human cells.

    PubMed

    Riches, Lucy C; Lynch, Anthony M; Gooderham, Nigel J

    2010-03-01

    Although DNA damage proteins are infrequently regulated at the transcriptional level, RAD52 mRNA levels appear to be significantly induced in human cells following methyl methanesulphonate (MMS) and Etoposide treatment. Studies have so far been limited to biochemical analysis of cellular extracts and we aimed to extend this observation to whole cells. To address this, we have developed a series of molecular beacon (MB) probes that fluoresce upon hybridising with RAD52 mRNA sequence. MB's are synthetic hairpin probes, which generate a significant fluorescent signal only upon hybridising complementary nucleotide. Three MB's are described herein, which display differential sensitivity, specificity and stability. In particular, the suitability of a texas red-labelled DNA MB (TR-MB), a dual-labelled (FAM-TAMRA) fluorescence resonance energy transfer-capable DNA MB (FRET-MB) and a FAM-labelled MB of 2'-O-methylated RNA backbone (FAM-MB) was investigated. We conclude that FAM-MB is most suitable for intracellular applications, and demonstrate a positive correlation between MB fluorescence intensity, RAD52 gene expression and both gamma ionising radiation and MMS concentration in human TK6 cells. RAD52 contribution to DNA repair has been ascribed to its role in homologous recombination (HR) and therefore we propose FAM-MB could be a potential tool for discriminating between substrates of HR and non-homologous end joining (NHEJ).

  7. The human and mouse homologs of the yeat RAD52 gene: cDNA cloning, sequence analysis, assignment to human chromosome 12p12.2-p13, and mRNA expression in mouse tissues

    SciTech Connect

    Shen, Z.; Chen, D.J.; Denison, K.

    1995-01-01

    The yeast Saccharomyces cerevisiae RAD52 gene is involved in DNA double-strand break repair and mitotic/meiotic recombination. The N-terminal amino acid sequence of yeast S. cerevisiae, Schizosaccharomyces pombe, and Kluyveromyces lactis and chicken is highly conserved. Using the technology of mixed oligonucleotide primed amplification of cDNA (MOPAC), two mouse RAD52 homologous cDNA fragments were amplified and sequenced. Subsequently, we have cloned the cDNA of the human and mouse homologs of yeast RAD52 gene by screening cDNA libraries using the identified mouse cDNA fragments. Sequence analysis of cDNA derived amino acid revealed a highly conserved N-terminus among human, mouse, chicken, and yeast RAD52 genes. The human RAD52 gene was assigned to chromosome 12p12.2-p13 by fluorescence in situ hybridization, R-banding, and DNA analysis of somatic cell hybrids. Unlike chicken RAD52 and mouse RAD51, no significant difference in mouse RAD52 mRNA level was found among mouse heart, brain, spleen, lung, liver, skeletal muscle, kidney, and testis. In addition to an {approximately}1.9-kb RAD52 mRNA band that is present in all of the tested tissues, an extra mRNA species of {approximately}0.85 kb was detectable in mouse testis. 40 refs., 7 figs., 1 tab.

  8. Plasmid Recombination in a Rad52 Mutant of Saccharomyces Cerevisiae

    PubMed Central

    Dornfeld, K. J.; Livingston, D. M.

    1992-01-01

    Using plasmids capable of undergoing intramolecular recombination, we have compared the rates and the molecular outcomes of recombination events in a wild-type and a rad52 strain of Saccharomyces cerevisiae. The plasmids contain his3 heteroalleles oriented in either an inverted or a direct repeat. Inverted repeat plasmids recombine approximately 20-fold less frequently in the mutant than in the wild-type strain. Most events from both cell types have continuous coconversion tracts extending along one of the homologous segments. Reciprocal exchange occurs in fewer than 30% of events. Direct repeat plasmids recombine at rates comparable to those of inverted repeat plasmids in wild-type cells. Direct repeat conversion tracts are similar to inverted repeat conversion tracts in their continuity and length. Inverted and direct repeat plasmid recombination differ in two respects. First, rad52 does not affect the rate of direct repeat recombination as drastically as the rate of inverted repeat recombination. Second, direct repeat plasmids undergo crossing over more frequently than inverted repeat plasmids. In addition, crossovers constitute a larger fraction of mutant than wild-type direct repeat events. Many crossover events from both cell types are unusual in that the crossover HIS3 allele is within a plasmid containing the parental his3 heteroalleles. PMID:1644271

  9. Enhancing cytochrome P450-mediated conversions in P. pastoris through RAD52 over-expression and optimizing the cultivation conditions.

    PubMed

    Wriessnegger, Tamara; Moser, Sandra; Emmerstorfer-Augustin, Anita; Leitner, Erich; Müller, Monika; Kaluzna, Iwona; Schürmann, Martin; Mink, Daniel; Pichler, Harald

    2016-04-01

    Cytochrome P450 enzymes (CYPs) play an essential role in the biosynthesis of various natural compounds by catalyzing regio- and stereospecific hydroxylation reactions. Thus, CYP activities are of great interest in the production of fine chemicals, pharmaceutical compounds or flavors and fragrances. Industrial applicability of CYPs has driven extensive research efforts aimed at improving the performance of these enzymes to generate robust biocatalysts. Recently, our group has identified CYP-mediated hydroxylation of (+)-valencene as a major bottleneck in the biosynthesis of trans-nootkatol and (+)-nootkatone in Pichia pastoris. In the current study, we aimed at enhancing CYP-mediated (+)-valencene hydroxylation by over-expressing target genes identified through transcriptome analysis in P. pastoris. Strikingly, over-expression of the DNA repair and recombination gene RAD52 had a distinctly positive effect on trans-nootkatol formation. Combining RAD52 over-expression with optimization of whole-cell biotransformation conditions, i.e. optimized media composition and cultivation at higher pH value, enhanced trans-nootkatol production 5-fold compared to the initial strain and condition. These engineering approaches appear to be generally applicable for enhanced hydroxylation of hydrophobic compounds in P. pastoris as confirmed here for two additional membrane-attached CYPs, namely the limonene-3-hydroxylase from Mentha piperita and the human CYP2D6. PMID:26898115

  10. The role of recombination and RAD52 in mutation of chromosomal DNA transformed into yeast.

    PubMed Central

    Larionov, V; Graves, J; Kouprina, N; Resnick, M A

    1994-01-01

    While transformation is a prominent tool for genetic analysis and genome manipulation in many organisms, transforming DNA has often been found to be unstable relative to established molecules. We determined the potential for transformation-associated mutations in a 360 kb yeast chromosome III composed primarily of unique DNA. Wild-type and rad52 Saccharomyces cerevisiae strains were transformed with either a homologous chromosome III or a diverged chromosome III from S. carlsbergensis. The host strain chromosome III had a conditional centromere allowing it to be lost on galactose medium so that recessive mutations in the transformed chromosome could be identified. Following transformation of a RAD+ strain with the homologous chromosome, there were frequent changes in the incoming chromosome, including large deletions and mutations that do not lead to detectable changes in chromosome size. Based on results with the diverged chromosome, interchromosomal recombinational interactions were the source of many of the changes. Even though rad52 exhibits elevated mitotic mutation rates, the percentage of transformed diverged chromosomes incapable of substituting for the resident chromosome was not increased in rad52 compared to the wild-type strain, indicating that the mutator phenotype does not extend to transforming chromosomal DNA. Based on these results and our previous observation that the incidence of large mutations is reduced during the cloning of mammalian DNA into a rad52 as compared to a RAD+ strain, a rad52 host is well-suited for cloning DNA segments in which gene function must be maintained. Images PMID:7937151

  11. Rad51–Rad52 Mediated Maintenance of Centromeric Chromatin in Candida albicans

    PubMed Central

    Mitra, Sreyoshi; Gómez-Raja, Jonathan; Larriba, Germán; Dubey, Dharani Dhar; Sanyal, Kaustuv

    2014-01-01

    Specification of the centromere location in most eukaryotes is not solely dependent on the DNA sequence. However, the non-genetic determinants of centromere identity are not clearly defined. While multiple mechanisms, individually or in concert, may specify centromeres epigenetically, most studies in this area are focused on a universal factor, a centromere-specific histone H3 variant CENP-A, often considered as the epigenetic determinant of centromere identity. In spite of variable timing of its loading at centromeres across species, a replication coupled early S phase deposition of CENP-A is found in most yeast centromeres. Centromeres are the earliest replicating chromosomal regions in a pathogenic budding yeast Candida albicans. Using a 2-dimensional agarose gel electrophoresis assay, we identify replication origins (ORI7-LI and ORI7-RI) proximal to an early replicating centromere (CEN7) in C. albicans. We show that the replication forks stall at CEN7 in a kinetochore dependent manner and fork stalling is reduced in the absence of the homologous recombination (HR) proteins Rad51 and Rad52. Deletion of ORI7-RI causes a significant reduction in the stalled fork signal and an increased loss rate of the altered chromosome 7. The HR proteins, Rad51 and Rad52, have been shown to play a role in fork restart. Confocal microscopy shows declustered kinetochores in rad51 and rad52 mutants, which are evidence of kinetochore disintegrity. CENP-ACaCse4 levels at centromeres, as determined by chromatin immunoprecipitation (ChIP) experiments, are reduced in absence of Rad51/Rad52 resulting in disruption of the kinetochore structure. Moreover, western blot analysis reveals that delocalized CENP-A molecules in HR mutants degrade in a similar fashion as in other kinetochore mutants described before. Finally, co-immunoprecipitation assays indicate that Rad51 and Rad52 physically interact with CENP-ACaCse4 in vivo. Thus, the HR proteins Rad51 and Rad52 epigenetically maintain

  12. The 12p13.33/RAD52 locus and genetic susceptibility to squamous cell cancers of upper aerodigestive tract.

    PubMed

    Delahaye-Sourdeix, Manon; Oliver, Javier; Timofeeva, Maria N; Gaborieau, Valérie; Johansson, Mattias; Chabrier, Amélie; Wozniak, Magdalena B; Brenner, Darren R; Vallée, Maxime P; Anantharaman, Devasena; Lagiou, Pagona; Holcátová, Ivana; Richiardi, Lorenzo; Kjaerheim, Kristina; Agudo, Antonio; Castellsagué, Xavier; Macfarlane, Tatiana V; Barzan, Luigi; Canova, Cristina; Thakker, Nalin S; Conway, David I; Znaor, Ariana; Healy, Claire M; Ahrens, Wolfgang; Zaridze, David; Szeszenia-Dabrowska, Neonilia; Lissowska, Jolanta; Fabianova, Eleonora; Mates, Ioan Nicolae; Bencko, Vladimir; Foretova, Lenka; Janout, Vladimir; Curado, Maria Paula; Koifman, Sergio; Menezes, Ana; Wünsch-Filho, Victor; Eluf-Neto, José; Boffetta, Paolo; Garrote, Leticia Fernández; Serraino, Diego; Lener, Marcin; Jaworowska, Ewa; Lubiński, Jan; Boccia, Stefania; Rajkumar, Thangarajan; Samant, Tanuja A; Mahimkar, Manoj B; Matsuo, Keitaro; Franceschi, Silvia; Byrnes, Graham; Brennan, Paul; McKay, James D

    2015-01-01

    Genetic variants located within the 12p13.33/RAD52 locus have been associated with lung squamous cell carcinoma (LUSC). Here, within 5,947 UADT cancers and 7,789 controls from 9 different studies, we found rs10849605, a common intronic variant in RAD52, to be also associated with upper aerodigestive tract (UADT) squamous cell carcinoma cases (OR = 1.09, 95% CI: 1.04-1.15, p = 6x10(-4)). We additionally identified rs10849605 as a RAD52 cis-eQTL inUADT(p = 1x10(-3)) and LUSC (p = 9x10(-4)) tumours, with the UADT/LUSC risk allele correlated with increased RAD52 expression levels. The 12p13.33 locus, encompassing rs10849605/RAD52, was identified as a significant somatic focal copy number amplification in UADT(n = 374, q-value = 0.075) and LUSC (n = 464, q-value = 0.007) tumors and correlated with higher RAD52 tumor expression levels (p = 6x10(-48) and p = 3x10(-29) in UADT and LUSC, respectively). In combination, these results implicate increased RAD52 expression in both genetic susceptibility and tumorigenesis of UADT and LUSC tumors.

  13. Large human YACs constructed in a rad52 strain show a reduced rate of chimerism

    SciTech Connect

    Haldi, M.; Perrot, V.; Saumier, M.

    1994-12-01

    Current YAC libraries are plagued by a high frequency of chimeras - that is, clones containing fragments from multiple genomic regions. Chimeras are thought to arise largely through recombination in the yeast host cell. If so, the use of recombination-deficient yeast strains, such as rad52 mutants, might be expected to alleviate the problem. Here, we report the construction of megabase-sized human YACs in the rad52 strain MHY5201 and the determination of their rate of chimerism by fluorescence in situ hybridization analysis. Examination of 48 YACs showed a rate of chimerism of at most 8%, whereas YACs constructed in the wildtype host AB1380 showed a rate of about 50%. These results show that it is possible to significantly decrease the rate of YAC chimerism through the use of appropriate yeast host strains. 27 refs., 3 figs., 3 tabs.

  14. Temperate Phages Acquire DNA from Defective Prophages by Relaxed Homologous Recombination: The Role of Rad52-Like Recombinases

    PubMed Central

    De Paepe, Marianne; Hutinet, Geoffrey; Son, Olivier; Amarir-Bouhram, Jihane; Schbath, Sophie; Petit, Marie-Agnès

    2014-01-01

    Bacteriophages (or phages) dominate the biosphere both numerically and in terms of genetic diversity. In particular, genomic comparisons suggest a remarkable level of horizontal gene transfer among temperate phages, favoring a high evolution rate. Molecular mechanisms of this pervasive mosaicism are mostly unknown. One hypothesis is that phage encoded recombinases are key players in these horizontal transfers, thanks to their high efficiency and low fidelity. Here, we associate two complementary in vivo assays and a bioinformatics analysis to address the role of phage encoded recombinases in genomic mosaicism. The first assay allowed determining the genetic determinants of mosaic formation between lambdoid phages and Escherichia coli prophage remnants. In the second assay, recombination was monitored between sequences on phage λ, and allowed to compare the performance of three different Rad52-like recombinases on the same substrate. We also addressed the importance of homologous recombination in phage evolution by a genomic comparison of 84 E. coli virulent and temperate phages or prophages. We demonstrate that mosaics are mainly generated by homology-driven mechanisms that tolerate high substrate divergence. We show that phage encoded Rad52-like recombinases act independently of RecA, and that they are relatively more efficient when the exchanged fragments are divergent. We also show that accessory phage genes orf and rap contribute to mosaicism. A bioinformatics analysis strengthens our experimental results by showing that homologous recombination left traces in temperate phage genomes at the borders of recently exchanged fragments. We found no evidence of exchanges between virulent and temperate phages of E. coli. Altogether, our results demonstrate that Rad52-like recombinases promote gene shuffling among temperate phages, accelerating their evolution. This mechanism may prove to be more general, as other mobile genetic elements such as ICE encode Rad52-like

  15. The RAD52-like protein ODB1 is required for the efficient excision of two mitochondrial introns spliced via first-step hydrolysis.

    PubMed

    Gualberto, José M; Le Ret, Monique; Beator, Barbara; Kühn, Kristina

    2015-07-27

    Transcript splicing in plant mitochondria involves numerous nucleus-encoded factors, most of which are of eukaryotic origin. Some of these belong to protein families initially characterised to perform unrelated functions. The RAD52-like ODB1 protein has been reported to have roles in homologous recombination-dependent DNA repair in the nuclear and mitochondrial compartments in Arabidopsis thaliana. We show that it is additionally involved in splicing and facilitates the excision of two cis-spliced group II introns, nad1 intron 2 and nad2 intron 1, in Arabidopsis mitochondria. odb1 mutants lacking detectable amounts of ODB1 protein over-accumulated incompletely spliced nad1 and nad2 transcripts. The two ODB1-dependent introns were both found to splice via first-step hydrolysis and to be released as linear or circular molecules instead of lariats. Our systematic analysis of the structures of excised introns in Arabidopsis mitochondria revealed several other hydrolytically spliced group II introns in addition to nad1 intron 2 and nad2 intron 1, indicating that ODB1 is not a general determinant of the hydrolytic splicing pathway.

  16. The RAD52-like protein ODB1 is required for the efficient excision of two mitochondrial introns spliced via first-step hydrolysis

    PubMed Central

    Gualberto, José M.; Le Ret, Monique; Beator, Barbara; Kühn, Kristina

    2015-01-01

    Transcript splicing in plant mitochondria involves numerous nucleus-encoded factors, most of which are of eukaryotic origin. Some of these belong to protein families initially characterised to perform unrelated functions. The RAD52-like ODB1 protein has been reported to have roles in homologous recombination-dependent DNA repair in the nuclear and mitochondrial compartments in Arabidopsis thaliana. We show that it is additionally involved in splicing and facilitates the excision of two cis-spliced group II introns, nad1 intron 2 and nad2 intron 1, in Arabidopsis mitochondria. odb1 mutants lacking detectable amounts of ODB1 protein over-accumulated incompletely spliced nad1 and nad2 transcripts. The two ODB1-dependent introns were both found to splice via first-step hydrolysis and to be released as linear or circular molecules instead of lariats. Our systematic analysis of the structures of excised introns in Arabidopsis mitochondria revealed several other hydrolytically spliced group II introns in addition to nad1 intron 2 and nad2 intron 1, indicating that ODB1 is not a general determinant of the hydrolytic splicing pathway. PMID:26048959

  17. Hypospadias Repair: A Single Centre Experience

    PubMed Central

    Majeed, Abdul; Ullah, Hidayat; Naz, Shazia; Shah, Syed Asif; Tahmeed, Tahmeedullah; Yousaf, Kanwal; Tahir, Muhammad

    2014-01-01

    Objectives. To determine the demographics and analyze the management and factors influencing the postoperative complications of hypospadias repair. Settings. Hayatabad Medical Complex Peshawar, Pakistan, from January 2007 to December 2011. Material and Methods. All male patients presenting with hypospadias irrespective of their ages were included in the study. The data were acquired from the hospital's database and analyzed with Statistical Package for Social Sciences (SPSS). Results. A total of 428 patients with mean age of 8.12 ± 5.04 SD presented for hypospadias repair. Midpenile hypospadias were the most common. Chordee, meatal abnormalities, cryptorchidism, and inguinal hernias were observed in 74.3%, 9.6%, 2.8%, and 2.1% cases, respectively. Two-stage (Bracka) and TIP (tubularized incised urethral plate) repairs were performed in 76.2% and 20.8% of cases, respectively. The most common complications were edema and urethrocutaneous fistula (UCF). The complications were significantly lower in the hands of specialists than residents (P-value = 0.0086). The two-stage hypospadias repair resulted in higher complications frequency than single-stage repair (P value = 0.0001). Conclusion. Hypospadias surgery has a long learning curve because it requires a great deal of temperament, surgical skill and acquaintance with magnifications. Single-stage repair should be encouraged wherever applicable due to its lower postoperative complications. PMID:24579043

  18. Association Between Single-Nucleotide Polymorphisms in Hormone Metabolism and DNA Repair Genes and Epithelial Ovarian Cancer: Results from Two Australian Studies and an Additional Validation Set

    PubMed Central

    Beesley, Jonathan; Jordan, Susan J.; Spurdle, Amanda B.; Song, Honglin; Ramus, Susan J.; Kjaer, Suzanne Kruger; Hogdall, Estrid; DiCioccio, Richard A.; McGuire, Valerie; Whittemore, Alice S.; Gayther, Simon A.; Pharoah, Paul D.P.; Webb, Penelope M.; Chenevix-Trench, Georgia

    2009-01-01

    Although some high-risk ovarian cancer genes have been identified, it is likely that common low penetrance alleles exist that confer some increase in ovarian cancer risk. We have genotyped nine putative functional single-nucleotide polymorphisms (SNP) in genes involved in steroid hormone synthesis (SRD5A2, CYP19A1, HSB17B1, and HSD17B4) and DNA repair (XRCC2, XRCC3, BRCA2, and RAD52) using two Australian ovarian cancer case-control studies, comprising a total of 1,466 cases and 1,821 controls of Caucasian origin. Genotype frequencies in cases and controls were compared using logistic regression. The only SNP we found to be associated with ovarian cancer risk in both of these two studies was SRD5A2 V89L (rs523349), which showed a significant trend of increasing risk per rare allele (P = 0.00002). We then genotyped another SNP in this gene (rs632148; r2 = 0.945 with V89L) in an attempt to validate this finding in an independent set of 1,479 cases and 2,452 controls from United Kingdom, United States, and Denmark. There was no association between rs632148 and ovarian cancer risk in the validation samples, and overall, there was no significant heterogeneity between the results of the five studies. Further analyses of SNPs in this gene are therefore warranted to determine whether SRD5A2 plays a role in ovarian cancer predisposition. PMID:18086758

  19. Budding yeast Rad50, Mre11, Xrs2, and Hdf1, but not Rad52, are involved in the formation of deletions on a dicentric plasmid.

    PubMed

    Tsukamoto, Y; Kato, J; Ikeda, H

    1997-08-01

    We have previously shown that the RAD50, RAD52, MRE11, XRS2, and HDF1 genes of Saccharomyces cervisiae are involved in the formation of deletions by illegitimate recombination on a monocentric plasmid. In this study, we investigated the effects of mutations of these genes on formation of deletions of a dicentric plasmid, in which DNA double-strand breaks are expected to occur frequently because the two centromeres are pulled to opposite poles in mitosis. We transformed yeast cells with a dicentric plasmid, and after incubation for a few division cycles, cells carrying deleted plasmids were detected using negative selection markers. Deletions occurred at a higher frequency than on the monocentric plasmid and there were short regions of homology at the recombination junctions as observed on the monocentric plasmid. In rad50, mre11, xrs2, and hdf1 mutants, the frequency of occurrence of deletions was reduced by about 50-fold, while in the rad52 mutant, it was comparable to that in the wild-type strain. The end-joining functions of Rad50, Mre11, Xrs2, and Hdf1, suggest that these proteins play important roles in the joining of DNA ends produced on the dicentric plasmid during mitosis. PMID:9294039

  20. Single-Word Intelligibility in Speakers with Repaired Cleft Palate

    ERIC Educational Resources Information Center

    Whitehill, Tara L.; Chau, Cynthia H.-F.

    2004-01-01

    Many speakers with repaired cleft palate have reduced intelligibility, but there are limitations with current procedures for assessing intelligibility. The aim of this study was to construct a single-word intelligibility test for speakers with cleft palate. The test used a multiple-choice identification format, and was based on phonetic contrasts…

  1. BRG1 promotes the repair of DNA double-strand breaks by facilitating the replacement of RPA with RAD51

    PubMed Central

    Qi, Wenjing; Wang, Ruoxi; Chen, Hongyu; Wang, Xiaolin; Xiao, Ting; Boldogh, Istvan; Ba, Xueqing; Han, Liping; Zeng, Xianlu

    2015-01-01

    ABSTRACT DNA double-strand breaks (DSBs) are a type of lethal DNA damage. The repair of DSBs requires tight coordination between the factors modulating chromatin structure and the DNA repair machinery. BRG1, the ATPase subunit of the chromatin remodelling complex Switch/Sucrose non-fermentable (SWI/SNF), is often linked to tumorigenesis and genome instability, and its role in DSB repair remains largely unclear. In the present study, we show that BRG1 is recruited to DSB sites and enhances DSB repair. Using DR-GFP and EJ5-GFP reporter systems, we demonstrate that BRG1 facilitates homologous recombination repair rather than nonhomologous end-joining (NHEJ) repair. Moreover, the BRG1–RAD52 complex mediates the replacement of RPA with RAD51 on single-stranded DNA (ssDNA) to initiate DNA strand invasion. Loss of BRG1 results in a failure of RAD51 loading onto ssDNA, abnormal homologous recombination repair and enhanced DSB-induced lethality. Our present study provides a mechanistic insight into how BRG1, which is known to be involved in chromatin remodelling, plays a substantial role in the homologous recombination repair pathway in mammalian cells. PMID:25395584

  2. Genetic variants in DNA double-strand break repair genes and risk of salivary gland carcinoma: a case-control study.

    PubMed

    Xu, Li; Tang, Hongwei; El-Naggar, Adel K; Wei, Peng; Sturgis, Erich M

    2015-01-01

    DNA double strand break (DSB) repair is the primary defense mechanism against ionizing radiation-induced DNA damage. Ionizing radiation is the only established risk factor for salivary gland carcinoma (SGC). We hypothesized that genetic variants in DSB repair genes contribute to individual variation in susceptibility to SGC. To test this hypothesis, we conducted a case-control study in which we analyzed 415 single nucleotide polymorphisms (SNPs) in 45 DSB repair genes in 352 SGC cases and 598 controls. Multivariate logistic regression analysis was performed to calculate odds ratios (ORs) and 95% confidence intervals (CIs). Rs3748522 in RAD52 and rs13180356 in XRCC4 were significantly associated with SGC after Bonferroni adjustment; ORs (95% CIs) for the variant alleles of these SNPs were 1.71 (1.40-2.09, P = 1.70 × 10(-7)) and 0.58 (0.45-0.74, P = 2.00 × 10(-5)) respectively. The genetic effects were modulated by histological subtype. The association of RAD52-rs3748522 with SGC was strongest for mucoepidermoid carcinoma (OR = 2.21, 95% CI: 1.55-3.15, P = 1.25 × 10(-5), n = 74), and the association of XRCC4-rs13180356 with SGC was strongest for adenoid cystic carcinoma (OR = 0.60, 95% CI: 0.42-0.87, P = 6.91 × 10(-3), n = 123). Gene-level association analysis revealed one gene, PRKDC, with a marginally significant association with SGC risk in non-Hispanic whites. To our knowledge, this study is the first to comprehensively evaluate the genetic effect of DSB repair genes on SGC risk. Our results indicate that genetic variants in the DSB repair pathways contribute to inter-individual differences in susceptibility to SGC and show that the impact of genetic variants differs by histological subtype. Independent studies are warranted to confirm these findings. PMID:26035306

  3. Involvement of homologous recombination repair after proton-induced DNA damage.

    PubMed

    Rostek, C; Turner, E L; Robbins, M; Rightnar, S; Xiao, W; Obenaus, A; Harkness, T A A

    2008-03-01

    Protection from chronic exposure to cosmic radiation, which is primarily composed of protons, in future manned missions to Mars and beyond is considered to be a key unresolved issue. To model the effects of cosmic radiation on a living cell, we used Saccharomyces cerevisiae cells harboring various deletions of DNA repair genes to investigate the response of cells to DNA strand breaks caused by exposure to 250 MeV proton irradiation (linear energy transfer of 0.41 keV/microm). In our study, DNA strand breaks induced by exposure to protons were predominantly repaired via the homologous recombination and postreplication repair pathways. We simulated chronic exposure to proton irradiation by treating cells from colonies that survived proton treatment, after several rounds of subculturing, to a second proton dose, as well as additional cell stressors. In general, cells cultured from proton surviving colonies were not more sensitive to secondary cell stressors. However, cells from rad52delta colonies that survived proton treatment showed increased resistance to secondary stressors, such as gamma-rays (1.17 and 1.33 MeV; 0.267 keV/microm), ultraviolet (UV) and proton irradiation and elevated temperatures. Resistance to secondary stressors was also observed in rad52delta cells that survived exposure to gamma-rays, rather than protons, but this was not observed to occur in rad52delta cells after UV irradiation. rad52delta cells that survived exposure to protons, followed by gamma-rays (proton surviving colonies were cultured prior to gamma-ray exposure), exhibited an additive effect, whereby these cells had a further increase in stress resistance. A genetic analysis indicated that increased stress resistance is most likely due to a second-site mutation that suppresses the rad52delta phenotype. We will discuss possible origins of these second-site mutations. PMID:18267950

  4. Laparoscopic repair of urogenital fistulae: A single centre experience

    PubMed Central

    Sharma, Sumit; Rizvi, Syed Jamal; Bethur, Santhosh Shivanandaiah; Bansal, Jyoti; Qadri, Syed Javid Farooq; Modi, Pranjal

    2014-01-01

    CONTEXT: Sparse literature exists on laparoscopic repair of urogenital fistulae (UGF). AIMS: The purpose of the following study is to report our experience of laparoscopic UGF repair with emphasis on important steps for a successful laparoscopic repair. SETTINGS AND DESIGN: Data of patients who underwent laparoscopic repair of UGF from 2003 to 2012 was retrospectively reviewed. MATERIALS AND METHODS: Data was reviewed as to the aetiology, prior failed attempts, size, number and location of fistula, mean operative time, blood loss, post-operative storage/voiding symptoms and episodes of urinary tract infections (UTI). RESULTS: Laparoscopic repair of 22 supratrigonal vesicovaginal fistulae (VVF) (five recurrent) and 31 ureterovaginal fistulae (UVF) was performed. VVF followed transabdominal hysterectomy (14), lower segment caesarean section (LSCS) (7) and oophrectomy (1). UVF followed laparoscopy assisted vaginal hysterectomy (18), transvaginal hysterectomy (2) and transabdominal hysterectomy (10) and LSCS (1). Mean VVF size was 14 mm. Mean operative time and blood loss for VVF and UVF were 140 min, 75 ml and 130 min, 60 ml respectively. In 20 VVF repairs tissue was interposed between non-overlapping suture lines. Vesico-psoas hitch was done in 29 patients of urterovaginal fistulae. All patients were continent following surgery. There were no urinary complaints in VVF patients and no UTI in UVF patients over a median follow-up of 3.2 years and 2.8 years respectively. CONCLUSION: Laparoscopic repair of UGF gives easy, quick access to the pelvic cavity. Interposition of tissue during VVF repair and vesico-psoas hitch during UVF repair form important steps to ensure successful repair. PMID:25336817

  5. All-Endoscopic Single-Row Repair of Full-Thickness Gluteus Medius Tears

    PubMed Central

    Levy, David M.; Bogunovic, Ljiljana; Grzybowski, Jeffrey S.; Kuhns, Benjamin D.; Bush-Joseph, Charles A.; Nho, Shane J.

    2016-01-01

    Abductor tendon tears typically develop insidiously in middle-aged women and can lead to debilitating lateral hip pain and a Trendelenburg limp. The gluteus medius tendon is most commonly torn and may show fatty degeneration over time, similar to the rotator cuff muscles of the shoulder. Endoscopic repair offers a therapeutic alternative to traditional open techniques. This article describes the workup, examination, and endoscopic repair of a full-thickness gluteus medius tear presenting as lateral hip pain and weakness. The surgical repair for this case used a single-row suture anchor technique. In addition, the indications and technique for a double-row repair will be discussed. PMID:27073767

  6. RAD59 is Required for Efficient Repair of Simultaneous Double-Strand Breaks Resulting in Translocations in Saccharomyces cerevisiae

    PubMed Central

    Pannunzio, Nicholas R.; Manthey, Glenn M.; Bailis, Adam M.

    2008-01-01

    Exposure to ionizing radiation results in a variety of genome rearrangements that have been linked to tumor formation. Many of these rearrangements are thought to arise from the repair of double-strand breaks (DSBs) by several mechanisms, including homologous recombination (HR) between repetitive sequences dispersed throughout the genome. Doses of radiation sufficient to create DSBs in or near multiple repetitive elements simultaneously could initiate single-strand annealing (SSA), a highly-efficient, though mutagenic, mode of DSB repair. We have investigated the genetic control of the formation of translocations that occur spontaneously and those that form after the generation of DSBs adjacent to homologous sequences on two, non-homologous chromosomes in Saccharomyces cerevisiae. We found that mutations in a variety of DNA repair genes have distinct effects on break-stimulated translocation. Furthermore, the genetic requirements for repair using 300 bp and 60 bp recombination substrates were different, suggesting that the SSA apparatus may be altered in response to changing substrate lengths. Notably, RAD59 was found to play a particularly significant role in recombination between the short substrates that was partially independent of that of RAD52. The high frequency of these events suggests that SSA may be an important mechanism of genome rearrangement following acute radiation exposure. PMID:18373960

  7. The Prevention of Repeat-Associated Deletions in Saccharomyces Cerevisiae by Mismatch Repair Depends on Size and Origin of Deletions

    PubMed Central

    Tran, H. T.; Gordenin, D. A.; Resnick, M. A.

    1996-01-01

    We have investigated the effects of mismatch repair on 1- to 61-bp deletions in the yeast Saccharomyces cerevisiae. The deletions are likely to involve unpaired loop intermediates resulting from DNA polymerase slippage. The mutator effects of mutations in the DNA polymerase δ (POL3) gene and the recombinational repair RAD52 gene were studied in combination with mismatch repair defects. The pol3-t mutation increased up to 1000-fold the rate of extended (7-61 bp) but not of 1-bp deletions. In a rad52 null mutant only the 1-bp deletions were increased (12-fold). The mismatch repair mutations pms1, msh2 and msh3 did not affect 31- and 61-bp deletions in the pol3-t but increased the rates of 7- and 1-bp deletions. We propose that loops less than or equal to seven bases generated during replication are subject to mismatch repair by the PMS1, MSH2, MSH3 system and that it cannot act on loops >=31 bases. In contrast to the pol3-t, the enhancement of 1-bp deletions in a rad52 mutant is not altered by a pms1 mutation. Thus, mismatch repair appears to be specific to errors of DNA synthesis generated during semiconservative replication. PMID:8844147

  8. Genetic Control or Repair and Adaptive Response to Low-Level DNA Damage

    SciTech Connect

    J. E. Haber

    2009-10-05

    Research was focused on how a single double-strand break - a model of low-dose ionizing radiation-induced DNA damage - could be studied in a simple model system, budding yeast. Breaks were induced in several different ways. We used the site-specific HO endonuclease to create a single DSB in all cells of the population so that its fate could be extensively analyzed genetically and molecularly. We also used two heterologous systems, the plant DS element and the Rag1/Rag2 proteins, to generate different types of DSBs, these containing hairpin ends that needed to be cleaved open before end-joining could take place. All three approaches yielded important new findings. We also extended our analysis of the Mre11 protein that plays key roles in both NHEJ and in homologous recombination. Finally we analyzed the poorly understood recombination events that were independent of the key recombination protein, Rad52. This line of inquiry was strongly motivated by the fact that vertebrate cells do not rely strongly on Rad52 for homologous recombination, so that some clues about alternative mechanisms could be gained by understanding how Rad52-independent recombination occurred. We found that the Mre11 complex was the most important element in Rad52-independent recombination.

  9. MicroRNA regulation of DNA repair gene expression in hypoxic stress.

    PubMed

    Crosby, Meredith E; Kulshreshtha, Ritu; Ivan, Mircea; Glazer, Peter M

    2009-02-01

    Genetic instability is a hallmark of cancer; the hypoxic tumor microenvironment has been implicated as a cause of this phenomenon. MicroRNAs (miR) are small nonprotein coding RNAs that can regulate various cellular pathways. We report here that two miRs, miR-210 and miR-373, are up-regulated in a hypoxia-inducible factor-1alpha-dependent manner in hypoxic cells. Bioinformatics analyses suggested that these miRs could regulate factors implicated in DNA repair pathways. Forced expression of miR-210 was found to suppress the levels of RAD52, which is a key factor in homology-dependent repair (HDR); the forced expression of miR-373 led to a reduction in the nucleotide excision repair (NER) protein, RAD23B, as well as in RAD52. Consistent with these results, both RAD52 and RAD23B were found to be down-regulated in hypoxia, but in both cases, the hypoxia-induced down-regulation could be partially reversed by antisense inhibition of miR-210 and miR-373. Importantly, luciferase reporter assays indicated that miR-210 is capable of interacting with the 3' untranslated region (UTR) of RAD52 and that miR-373 can act on the 3' UTR of RAD23B. These results indicate that hypoxia-inducible miR-210 and miR-373 play roles in modulating the expression levels of key proteins involved in the HDR and NER pathways, providing new mechanistic insight into the effect of hypoxia on DNA repair and genetic instability in cancer.

  10. A single double-strand break system reveals repair dynamics and mechanisms in heterochromatin and euchromatin.

    PubMed

    Janssen, Aniek; Breuer, Gregory A; Brinkman, Eva K; van der Meulen, Annelot I; Borden, Sean V; van Steensel, Bas; Bindra, Ranjit S; LaRocque, Jeannine R; Karpen, Gary H

    2016-07-15

    Repair of DNA double-strand breaks (DSBs) must be properly orchestrated in diverse chromatin regions to maintain genome stability. The choice between two main DSB repair pathways, nonhomologous end-joining (NHEJ) and homologous recombination (HR), is regulated by the cell cycle as well as chromatin context.Pericentromeric heterochromatin forms a distinct nuclear domain that is enriched for repetitive DNA sequences that pose significant challenges for genome stability. Heterochromatic DSBs display specialized temporal and spatial dynamics that differ from euchromatic DSBs. Although HR is thought to be the main pathway used to repair heterochromatic DSBs, direct tests of this hypothesis are lacking. Here, we developed an in vivo single DSB system for both heterochromatic and euchromatic loci in Drosophila melanogaster Live imaging of single DSBs in larval imaginal discs recapitulates the spatio-temporal dynamics observed for irradiation (IR)-induced breaks in cell culture. Importantly, live imaging and sequence analysis of repair products reveal that DSBs in euchromatin and heterochromatin are repaired with similar kinetics, employ both NHEJ and HR, and can use homologous chromosomes as an HR template. This direct analysis reveals important insights into heterochromatin DSB repair in animal tissues and provides a foundation for further explorations of repair mechanisms in different chromatin domains. PMID:27474442

  11. DNA repair of a single UV photoproduct in a designed nucleosome

    SciTech Connect

    Kosmoskil, Joseph V.; Ackerman, Eric J. ); Smerdon, Michael J.

    2001-08-28

    Eukaryotic DNA repair enzymes must interact with the architectural hierarchy of chromatin. The challenge of finding damaged DNA complexed with histone proteins in nucleosomes is complicated by the need to maintain local chromatin structures involved in regulating other DNA processing events. The heterogeneity of lesions induced by DNA-damaging agents has led us to design homogeneously damaged substrates to directly compare repair of naked DNA with that of nucleosomes. Here we report that nucleotide excision repair in Xenopus nuclear extracts can effectively repair a single UV radiation photoproduct located 5 bases from the dyad center of a positioned nucleosome, although the nucleosome is repaired at about half the rate at which the naked DNA fragment is. Extract repair within the nucleosome is > 50-fold more rapid than either enzymatic photoreversal or endonuclease cleavage of the lesion in vitro. Furthermore, nucleosome formation occurs (after repair) only on damaged naked DNA ( 165-bp fragments) during a 1-h incubation in these extracts, even in the presence of a large excess of undamaged DNA. This is an example of selective nucleosome assembly by Xenopus nuclear extracts on a short linear DNA fragment containing a DNA lesion.

  12. FEN1 participates in repair of the 5'-phosphotyrosyl terminus of DNA single-strand breaks.

    PubMed

    Kametani, Yukiko; Takahata, Chiaki; Narita, Takashi; Tanaka, Kiyoji; Iwai, Shigenori; Kuraoka, Isao

    2016-01-01

    Etoposide is a widely used anticancer drug and a DNA topoisomerase II (Top2) inhibitor. Etoposide produces Top2-attached single-strand breaks (Top2-SSB complex) and double-strand breaks (Top2-DSB complex) that are thought to induce cell death in tumor cells. The Top2-SSB complex is more abundant than the Top2-DSB complex. Human tyrosyl-DNA phosphodiesterase 2 (TDP2) is required for efficient repair of Top2-DSB complexes. However, the identities of the proteins involved in the repair of Top2-SSB complexes are unknown, although yeast genetic data indicate that 5' to 3' structure-specific DNA endonuclease activity is required for alternative repair of Top2 DNA damage. In this study, we purified a flap endonuclease 1 (FEN1) and xeroderma pigmentosum group G protein (XPG) in the 5' to 3' structure-specific DNA endonuclease family and synthesized single-strand break DNA substrates containing a 5'-phoshotyrosyl bond, mimicking the Top2-SSB complex. We found that FEN1 and XPG did not remove the 5'-phoshotyrosyl bond-containing DSB substrates but removed the 5'-phoshotyrosyl bond-containing SSB substrates. Under DNA repair conditions, FEN1 efficiently repaired the 5'-phoshotyrosyl bond-containing SSB substrates in the presence of DNA ligase and DNA polymerase. Therefore, FEN1 may play an important role in the repair of Top2-SSB complexes in etoposide-treated cells.

  13. Cisplatin DNA damage and repair maps of the human genome at single-nucleotide resolution

    PubMed Central

    Hu, Jinchuan; Lieb, Jason D.; Sancar, Aziz; Adar, Sheera

    2016-01-01

    Cisplatin is a major anticancer drug that kills cancer cells by damaging their DNA. Cancer cells cope with the drug by removal of the damages with nucleotide excision repair. We have developed methods to measure cisplatin adduct formation and its repair at single-nucleotide resolution. “Damage-seq” relies on the replication-blocking properties of the bulky base lesions to precisely map their location. “XR-seq” independently maps the removal of these damages by capturing and sequencing the excised oligomer released during repair. The damage and repair maps we generated reveal that damage distribution is essentially uniform and is dictated mostly by the underlying sequence. In contrast, cisplatin repair is heterogeneous in the genome and is affected by multiple factors including transcription and chromatin states. Thus, the overall effect of damages in the genome is primarily driven not by damage formation but by the repair efficiency. The combination of the Damage-seq and XR-seq methods has the potential for developing novel cancer therapeutic strategies. PMID:27688757

  14. Single-Port Parastomal Hernia Repair by Using 3-D Textile Implants

    PubMed Central

    Emmanuel, Klaus; Schrittwieser, Rudolf

    2014-01-01

    Background: Parastomal hernias (PSHs) are a frequent complication and remain a surgical challenge. We present a new option for single-port PSH repair with equilateral stoma relocation using preshaped, prosthetic 3-dimensional implants and flat mesh insertion in intraperitoneal onlay placement for additional augmentation of the abdominal wall. Methods: We describe our novel technique in detail and performed an analysis of prospectively collected data from patients who underwent single-port PSH repair, focusing on feasibility, conversions, and complications. Results: From September 2013 to January 2014, 9 patients with symptomatic PSHs were included. Two conversions to reduced-port laparoscopy using a second 3-mm trocar were required because of difficult adhesiolysis, dissection, and reduction of the hernia sac content. No major intra- or postoperative complications or reoperations were encountered. One patient incurred a peristomal wound healing defect that could be treated conservatively. Conclusion: We found that single-port PSH repair using preshaped, elastic 3-dimensional devices and additional flat mesh repair of the abdominal wall is feasible, safe, and beneficial, relating to optimal coverage of unstable stoma edges with wide overlap to all sides and simultaneous augmentation of the midline in the IPOM technique. The stoma relocation enables prolapse treatment and prevention. The features of a modular and rotatable multichannel port system offer benefits in clear dissection ongoing from a single port. Long-term follow-up data on an adequate number of patients are awaited to examine efficacy. PMID:25392655

  15. Knotless single-row rotator cuff repair: a comparative biomechanical study of 2 knotless suture anchors.

    PubMed

    Efird, Chad; Traub, Shaun; Baldini, Todd; Rioux-Forker, Dana; Spalazzi, Jeffrey P; Davisson, Twana; Hawkins, Monica; McCarty, Eric

    2013-08-01

    The purpose of this study was to compare the gap formation during cyclic loading, maximum repair strength, and failure mode of single-row full-thickness supraspinatus repairs performed using 2 knotless suture anchors with differing internal suture-retention mechanisms in a human cadaver model. Nine matched pairs of cadaver shoulders were used. Full-thickness tears were induced by detaching the supraspinatus tendon from the greater tuberosity. Single-row repairs were performed with either type I (Opus Magnum PI; ArthroCare, Austin, Texas) or type II (ReelX STT; Stryker, Mahwah, New Jersey) knotless suture anchors. The repaired tendon was cycled from 10 to 90 N for 500 cycles, followed by load to failure. Gap formation was measured at 5, 100, 200, 300, 400, and 500 cycles with a video digitizing system. Anchor type or location (anterior or posterior) had no effect on gap formation during cyclic loading regardless of position (anterior, P=.385; posterior, P=.389). Maximum load to failure was significantly greater (P=.018) for repairs performed with type II anchors (288±62 N) compared with type I anchors (179±39 N). Primary failure modes were anchor pullout and tendon tearing for type II anchors and suture slippage through the anchor for type I anchors. The internal ratcheting suture-retention mechanism of type II anchors may have helped this anchor outperform the suture-cinching mechanism of type I anchors by supporting significantly higher loads before failure and minimizing suture slippage, potentially leading to stronger repairs clinically. PMID:23937749

  16. Single incision Laparoscopic repair of post CABG sternotomy sub xiphoid hernia

    PubMed Central

    Shah, Haresh K; Chaudhari, Namita; Khopade, Suman; Thombare, Bhushan; Chavan, Shirish G

    2013-01-01

    The current decade has witnessed the evolution of Minimal Access Surgery (MAS) from Multi port Laparoscopy to Single Port Laparoscopy. The reduction of ports, subsequent scars and pain makes MAS more patients friendly. Symptomatic Subxiphoid Incisional hernias in patients having post CABG Sternotomy are surgically challenging. This is because of the difficult anatomical position i.e. sternum and the ribs superiorly and the diaphragm posteriorly. Another reason is high intra-abdominal pressure with the shearing forces of the musculature in the upper abdomen. Consequently the conventional open primary anatomical or mesh repairs are difficult to perform and have a high recurrence rate. Laparoscopy promises to be an effective technique to treat this condition. In this case report we describe the use of Laparoscopy in particular: Single Incision for the repair of CABG Sternotomy Subxiphoid Hernia along with relevant literature. This is the first report in English Language Literature. PMID:24250068

  17. Single-step scaffold-based cartilage repair in the knee: A systematic review.

    PubMed

    Fischer, Stefan; Kisser, Agnes

    2016-12-01

    Chondral lesions are difficult-to-treat entities that often affect young and active people. Moreover, cartilage has limited intrinsic healing potential. The purpose of this systematic literature review was to analyse whether the single-step scaffold-based cartilage repair in combination with microfracturing (MFx) is more effective and safe in comparison to MFx alone. From the three identified studies, it seems that the single-step scaffold-assisted cartilage repair in combination with MFx leads to similar short- to medium-term (up to five years follow-up) results, compared to MFx alone. All of the studies have shown improvements regarding joint functionality, pain and partly quality of life. PMID:27408497

  18. Single-step scaffold-based cartilage repair in the knee: A systematic review.

    PubMed

    Fischer, Stefan; Kisser, Agnes

    2016-12-01

    Chondral lesions are difficult-to-treat entities that often affect young and active people. Moreover, cartilage has limited intrinsic healing potential. The purpose of this systematic literature review was to analyse whether the single-step scaffold-based cartilage repair in combination with microfracturing (MFx) is more effective and safe in comparison to MFx alone. From the three identified studies, it seems that the single-step scaffold-assisted cartilage repair in combination with MFx leads to similar short- to medium-term (up to five years follow-up) results, compared to MFx alone. All of the studies have shown improvements regarding joint functionality, pain and partly quality of life.

  19. Single site and conventional totally extraperitoneal techniques for uncomplicated inguinal hernia repair: A comparative study

    PubMed Central

    de Araújo, Felipe Brandão Corrêa; Starling, Eduardo Simão; Maricevich, Marco; Tobias-Machado, Marcos

    2014-01-01

    OBJECTIVE: To demonstrate the feasibility of endoscopic extraperitoneal single site (EESS) inguinal hernia repair and compare it outcomes with the conventional totally extraperitoneal (TEP) technique. BACKGROUND: TEP inguinal hernia repair is a widely accepted alternative to conventional open technique with several perioperative advantages. Transumbilical laparoendoscopic singlesite surgery (LESS) is an emerging approach and has been reported for a number of surgical procedures with superior aesthetic results but other advantages need to be proven. PATIENTS AND METHODS: Thirty-eight uncomplicated inguinal hernias were repaired by EESS approach between January 2010 and January 2011. All procedures were performed through a 25 cm infraumbilical incision using the Alexis wound retractor attached to a surgical glove and three trocars. Body mass index, age, operative time, blood loss, complications, conversion rate, analgesia requirement, hospital stay, return to normal activities and patient satisfaction with aesthetic results were analysed and compared with the last 38 matched-pair group of patients who underwent a conventional TEP inguinal hernia repair by the same surgeon. RESULTS: All procedures were performed successfully with no conversion. In both unilateral and bilateral EESS inguinal repairs, the mean operative time was longer than conventional TEP (55± 20 vs. 40± 15 min, P = 0.049 and 70± 15 vs. 55± 10 min, P = 0.014). Aesthetic result was superior in the EESS group (2.88± 0.43 vs. 2.79± 0.51, P = 0.042). There was no difference between the two approaches regarding blood loss, complications, hospital stay, time until returns to normal activities and analgesic requirement. CONCLUSION: EESS inguinal hernia repair is safe and effective, with superior cosmetic results in the treatment of uncomplicated inguinal hernias. Other advantages of this new technique still need to be proven. PMID:25336820

  20. Generation of DNA single-strand displacement by compromised nucleotide excision repair

    PubMed Central

    Godon, Camille; Mourgues, Sophie; Nonnekens, Julie; Mourcet, Amandine; Coin, Fréderic; Vermeulen, Wim; Mari, Pierre-Olivier; Giglia-Mari, Giuseppina

    2012-01-01

    Nucleotide excision repair (NER) is a precisely coordinated process essential to avoid DNA damage-induced cellular malfunction and mutagenesis. Here, we investigate the mechanistic details and effects of the NER machinery when it is compromised by a pathologically significant mutation in a subunit of the repair/transcription factor TFIIH, namely XPD. In contrast to previous studies, we find that no single- or double-strand DNA breaks are produced at early time points after UV irradiation of cells bearing a specific XPD mutation, despite the presence of a clear histone H2AX phosphorylation (γH2AX) signal in the UV-exposed areas. We show that the observed γH2AX signal can be explained by the presence of longer single-strand gaps possibly generated by strand displacement. Our in vivo measurements also indicate a strongly reduced TFIIH-XPG binding that could promote single-strand displacement at the site of UV lesions. This finding not only highlights the crucial role of XPG's interactions with TFIIH for proper NER, but also sheds new light on how a faulty DNA repair process can induce extreme genomic instability in human patients. PMID:22863773

  1. Fluorogenic DNA ligase and base excision repair enzyme assays using substrates labeled with single fluorophores.

    PubMed

    Nikiforov, Theo T; Roman, Steven

    2015-05-15

    Continuing our work on fluorogenic substrates labeled with single fluorophores for nucleic acid modifying enzymes, here we describe the development of such substrates for DNA ligases and some base excision repair enzymes. These substrates are hairpin-type synthetic DNA molecules with a single fluorophore located on a base close to the 3' ends, an arrangement that results in strong fluorescence quenching. When such substrates are subjected to an enzymatic reaction, the position of the dyes relative to that end of the molecules is altered, resulting in significant fluorescence intensity changes. The ligase substrates described here were 5' phosphorylated and either blunt-ended or carrying short, self-complementary single-stranded 5' extensions. The ligation reactions resulted in the covalent joining of the ends of the molecules, decreasing the quenching effect of the terminal bases on the dyes. To generate fluorogenic substrates for the base excision repair enzymes formamido-pyrimidine-DNA glycosylase (FPG), human 8-oxo-G DNA glycosylase/AP lyase (hOGG1), endonuclease IV (EndoIV), and apurinic/apyrimidinic endonuclease (APE1), we introduced abasic sites or a modified nucleotide, 8-oxo-dG, at such positions that their enzymatic excision would result in the release of a short fluorescent fragment. This was also accompanied by strong fluorescence increases. Overall fluorescence changes ranged from approximately 4-fold (ligase reactions) to more than 20-fold (base excision repair reactions). PMID:25728944

  2. Cohesin and the nucleolus constrain the mobility of spontaneous repair foci.

    PubMed

    Dion, Vincent; Kalck, Véronique; Seeber, Andrew; Schleker, Thomas; Gasser, Susan M

    2013-11-01

    The regulation of chromatin mobility in response to DNA damage is important for homologous recombination in yeast. Anchorage reduces rates of recombination, whereas increased chromatin mobility correlates with more efficient homology search. Here we tracked the mobility and localization of spontaneous S-phase lesions bound by Rad52, and find that these foci have reduced movement, unlike enzymatically induced double-strand breaks. Moreover, spontaneous repair foci are positioned in the nuclear core, abutting the nucleolus. We show that cohesin and nucleolar integrity constrain the mobility of these foci, consistent with the notion that spontaneous, S-phase damage is preferentially repaired from the sister chromatid.

  3. Functional Outcomes After Double-Row Versus Single-Row Rotator Cuff Repair

    PubMed Central

    Nicholas, Stephen J.; Lee, Steven J.; Mullaney, Michael J.; Tyler, Timothy F.; Fukunaga, Takumi; Johnson, Christopher D.; McHugh, Malachy P.

    2016-01-01

    Background: The functional benefits of double-row (DR) versus single-row (SR) rotator cuff repair are not clearly established. Purpose: To examine the effect of DR versus SR rotator cuff repair on functional outcomes and strength recovery in patients with full-thickness tears. Study Design: Randomized controlled trial; Level of evidence, 2. Methods: Forty-nine patients were randomized to DR or SR repairs; 36 patients (13 women, 23 men; mean age, 62 ± 7 years; 20 SR, 16 DR) were assessed at a mean 2.2 ± 1.6 years after surgery (range, 1-7 years; tear size: 17 medium, 13 large, 9 massive). The following data were recorded prior to surgery and at follow-up: Penn shoulder score, American Shoulder and Elbow Surgeons (ASES), and Simple Shoulder Test (SST) results; range of motion (ROM) for shoulder flexion, external rotation (ER) at 0° and 90° of abduction, and internal rotation (IR) at 90° of abduction; and shoulder strength (Lafayette manual muscle tester) in empty- and full-can tests, abduction, and ER at 0° of abduction. Treatment (SR vs DR) × time (pre- vs postoperative) mixed-model analysis of variance was used to assess the effect of rotator cuff repair. Results: Rotator cuff repair markedly improved Penn, ASES, and SST scores (P < .001), with similar improvement between SR and DR repairs (treatment × time, P = .38-.10) and excellent scores at follow-up (DR vs SR: Penn, 91 ± 11 vs 92 ± 11 [P = .73]; ASES, 87 ± 12 vs 92 ± 12 [P = .21]; SST, 11.4 ± 1.0 vs 11.3 ± 1.0 [P = .76]). Patients with DR repairs lost ER ROM at 0° of abduction (preoperative to final follow-up, 7° ± 10° loss [P = .013]). ER ROM did not significantly change with SR repair (5° ± 14° gain, P = .16; treatment by time, P = .008). This effect was not apparent for ER ROM at 90° of abduction (treatment × time, P = .26). IR ROM improved from preoperative to final follow-up (P < .01; SR, 17° ± 27°; DR, 7° ± 21°; treatment × time, P = .23). Rotator cuff repair markedly

  4. Preferential repair in Saccharomyces cerevisiae rad mutants after induction of interstrand cross-links by 8-methoxypsoralen plus UVA.

    PubMed

    Meniel, V; Magaña-Schwencke, N; Averbeck, D

    1995-11-01

    The gene specific induction and the incision step of the removal of 8-methoxypsoralen (8-MOP) plus UVA-induced interstrand cross-links (ICL) was measured in repair mutants of Saccharomyces cerevisiae. Events were examined at the MAT alpha and HML alpha loci in mutants deficient in the repair of ICL, namely rad1, rad2 delta, rad52, pso2 and the rad16 mutant which is impaired in the removal of UV-induced pyrimidine dimers from the silent HML alpha locus. Previously, we observed in a wild-type strain (K107) preferential repair concerning the incision of 8-MOP photo-induced ICL. The present study indicates that the two mutants rad1 and rad2 delta show no repair in either locus, due presumably to their deficiency in the incision step of ICL repair. The rad52 mutant which is defective in recombination, is proficient in the preferential incision of ICL at the MAT alpha locus versus the HML alpha locus. The same is true for the pso2 mutant which also lacks the ability to perform complete repair of ICL. The rad16 mutant is unable to repair ICL in the silent locus HML alpha but is proficient in repair (i.e. the incision of ICL) in the transcriptionally active MAT alpha locus.

  5. Single-hit potentially lethal damage: evidence of its repair in mammalian cells

    SciTech Connect

    Utsumi, H.; Hill, C.K.; Ben-Hur, E.; Elkind, M.M.

    1981-09-01

    Following mid to large doses of X rays, or of fission spectrum neutrons, the repair of potentially lethal damage in V79 Chinese hamster cells can be inhibited by anisotonic phosphate-buffered saline or by medium containing 90% D/sub 2/O. The foregoing post-treatments do not affect the viability of unirradiated cells. Using single synchronized cells irradiated in late S-phase, the most resistant phase of the cell cycle, repair of potentially lethal damage in late S-phase, the most resistant phase of the cell cycle, repair of potentially lethal damage in the single-hit, initially exponential, or small-dose part of the survival curve was examined. The use of synchronized cells avoids misinterpretations due to population heterogeneity. The slope of the small-dose, exponential region of the neutron survival curve is much steeper than that of the x-ray survival curve. Even so, it is demonstrated with post-treatments consisting of hypertonic phosphate-buffered saline, medium containing D/sub 2/O,adiation is connected with their proliferation but not with the migration out from lymphoid organs.

  6. Enhanced gene repair mediated by methyl-CpG-modified single-stranded oligonucleotides

    PubMed Central

    Bertoni, Carmen; Rustagi, Arjun; Rando, Thomas A.

    2009-01-01

    Gene editing mediated by oligonucleotides has been shown to induce stable single base alterations in genomic DNA in both prokaryotic and eukaryotic organisms. However, the low frequencies of gene repair have limited its applicability for both basic manipulation of genomic sequences and for the development of therapeutic approaches for genetic disorders. Here, we show that single-stranded oligodeoxynucleotides (ssODNs) containing a methyl-CpG modification and capable of binding to the methyl-CpG binding domain protein 4 (MBD4) are able to induce >10-fold higher levels of gene correction than ssODNs lacking the specific modification. Correction was stably inherited through cell division and was confirmed at the protein, transcript and genomic levels. Downregulation of MBD4 expression using RNAi prevented the enhancement of gene correction efficacy obtained using the methyl-CpG-modified ssODN, demonstrating the specificity of the repair mechanism being recruited. Our data demonstrate that efficient manipulation of genomic targets can be achieved and controlled by the type of ssODN used and by modulation of the repair mechanism involved in the correction process. This new generation of ssODNs represents an important technological advance that is likely to have an impact on multiple applications, especially for gene therapy where permanent correction of the genetic defect has clear advantages over viral and other nonviral approaches currently being tested. PMID:19854937

  7. Visualization of DNA Double-Strand Break Repair at the Single-Molecule Level

    SciTech Connect

    Dynan, William S.; Li, Shuyi; Mernaugh, Raymond; Wragg, Stephanie; Takeda, Yoshihiko

    2003-03-27

    Exposure to low doses of ionizing radiation is universal. The signature injury from ionizing radiation exposure is induction of DNA double-strand breaks (DSBs). The first line of defense against DSBs is direct ligation of broken DNA ends via the nonhomologous end-joining pathway. Because even a relatively high environmental exposure induces only a few DSBs per cell, our current understanding of the response to this exposure is limited by the ability to measure DSB repair events reliably in situ at a single-molecule level. To address this need, we have taken advantage of biological amplification, measuring relocalization of proteins and detection of protein phosphorylation as a surrogate for detection of broken ends themselves. We describe the use of specific antibodies to investigate the kinetics and mechanism of repair of very small numbers of DSBs in human cells by the nonhomologous end-joining pathway.

  8. A dual role for mycobacterial RecO in RecA-dependent homologous recombination and RecA-independent single-strand annealing.

    PubMed

    Gupta, Richa; Ryzhikov, Mikhail; Koroleva, Olga; Unciuleac, Mihaela; Shuman, Stewart; Korolev, Sergey; Glickman, Michael S

    2013-02-01

    Mycobacteria have two genetically distinct pathways for the homology-directed repair of DNA double-strand breaks: homologous recombination (HR) and single-strand annealing (SSA). HR is abolished by deletion of RecA and reduced in the absence of the AdnAB helicase/nuclease. By contrast, SSA is RecA-independent and requires RecBCD. Here we examine the function of RecO in mycobacterial DNA recombination and repair. Loss of RecO elicits hypersensitivity to DNA damaging agents similar to that caused by deletion of RecA. We show that RecO participates in RecA-dependent HR in a pathway parallel to the AdnAB pathway. We also find that RecO plays a role in the RecA-independent SSA pathway. The mycobacterial RecO protein displays a zinc-dependent DNA binding activity in vitro and accelerates the annealing of SSB-coated single-stranded DNA. These findings establish a role for RecO in two pathways of mycobacterial DNA double-strand break repair and suggest an in vivo function for the DNA annealing activity of RecO proteins, thereby underscoring their similarity to eukaryal Rad52. PMID:23295671

  9. A dual role for mycobacterial RecO in RecA-dependent homologous recombination and RecA-independent single-strand annealing

    PubMed Central

    Gupta, Richa; Ryzhikov, Mikhail; Koroleva, Olga; Unciuleac, Mihaela; Shuman, Stewart; Korolev, Sergey; Glickman, Michael S.

    2013-01-01

    Mycobacteria have two genetically distinct pathways for the homology-directed repair of DNA double-strand breaks: homologous recombination (HR) and single-strand annealing (SSA). HR is abolished by deletion of RecA and reduced in the absence of the AdnAB helicase/nuclease. By contrast, SSA is RecA-independent and requires RecBCD. Here we examine the function of RecO in mycobacterial DNA recombination and repair. Loss of RecO elicits hypersensitivity to DNA damaging agents similar to that caused by deletion of RecA. We show that RecO participates in RecA-dependent HR in a pathway parallel to the AdnAB pathway. We also find that RecO plays a role in the RecA-independent SSA pathway. The mycobacterial RecO protein displays a zinc-dependent DNA binding activity in vitro and accelerates the annealing of SSB-coated single-stranded DNA. These findings establish a role for RecO in two pathways of mycobacterial DNA double-strand break repair and suggest an in vivo function for the DNA annealing activity of RecO proteins, thereby underscoring their similarity to eukaryal Rad52. PMID:23295671

  10. A Single-Strand Annealing Protein Clamps DNA to Detect and Secure Homology

    PubMed Central

    Ander, Marcel; Subramaniam, Sivaraman; Fahmy, Karim; Stewart, A. Francis; Schäffer, Erik

    2015-01-01

    Repair of DNA breaks by single-strand annealing (SSA) is a major mechanism for the maintenance of genomic integrity. SSA is promoted by proteins (single-strand-annealing proteins [SSAPs]), such as eukaryotic RAD52 and λ phage Redβ. These proteins use a short single-stranded region to find sequence identity and initiate homologous recombination. However, it is unclear how SSAPs detect homology and catalyze annealing. Using single-molecule experiments, we provide evidence that homology is recognized by Redβ monomers that weakly hold single DNA strands together. Once annealing begins, dimerization of Redβ clamps the double-stranded region and nucleates nucleoprotein filament growth. In this manner, DNA clamping ensures and secures a successful detection for DNA sequence homology. The clamp is characterized by a structural change of Redβ and a remarkable stability against force up to 200 pN. Our findings not only present a detailed explanation for SSAP action but also identify the DNA clamp as a very stable, noncovalent, DNA–protein interaction. PMID:26271032

  11. Double-strand break repair and colorectal cancer: gene variants within 3′ UTRs and microRNAs binding as modulators of cancer risk and clinical outcome

    PubMed Central

    Naccarati, Alessio; Rosa, Fabio; Vymetalkova, Veronika; Barone, Elisa; Jiraskova, Katerina; Di Gaetano, Cornelia; Novotny, Jan; Levy, Miroslav; Vodickova, Ludmila; Gemignani, Federica; Buchler, Tomas; Landi, Stefano

    2016-01-01

    Genetic variations in 3′ untranslated regions of target genes may affect microRNA binding, resulting in differential protein expression. microRNAs regulate DNA repair, and single-nucleotide polymorphisms in miRNA binding sites (miRSNPs) may account for interindividual differences in the DNA repair capacity. Our hypothesis is that miRSNPs in relevant DNA repair genes may ultimately affect cancer susceptibility and impact prognosis. In the present study, we analysed the association of polymorphisms in predicted microRNA target sites of double-strand breaks (DSBs) repair genes with colorectal cancer (CRC) risk and clinical outcome. Twenty-one miRSNPs in non-homologous end-joining and homologous recombination pathways were assessed in 1111 cases and 1469 controls. The variant CC genotype of rs2155209 in MRE11A was strongly associated with decreased cancer risk when compared with the other genotypes (OR 0.54, 95% CI 0.38–0.76, p = 0.0004). A reduced expression of the reporter gene was observed for the C allele of this polymorphism by in vitro assay, suggesting a more efficient interaction with potentially binding miRNAs. In colon cancer patients, the rs2155209 CC genotype was associated with shorter survival while the TT genotype of RAD52 rs11226 with longer survival when both compared with their respective more frequent genotypes (HR 1.63, 95% CI 1.06-2.51, p = 0.03 HR 0.60, 95% CI 0.41–0.89, p = 0.01, respectively). miRSNPs in DSB repair genes involved in the maintenance of genomic stability may have a role on CRC susceptibility and clinical outcome. PMID:26735576

  12. Summary of Meta-Analyses Dealing with Single-Row versus Double-Row Repair Techniques for Rotator Cuff Tears

    PubMed Central

    Spiegl, U.J.; Euler, S.A.; Millett, P.J.; Hepp, P.

    2016-01-01

    Background: Several meta-analyses of randomized clinical trials have been performed to analyze whether double-row (DR) rotator cuff repair (RCR) provides superior clinical outcomes and structural healing compared to single-row (SR) repair. The purpose of this study was to sum up the results of meta-analysis comparing SR and DR repair with respect on clinical outcomes and re-tear rates. Methods: A literature search was undertaken to identify all meta-analyses dealing with randomized controlled trials comparing clinical und structural outcomes after SR versus DR RCR. Results: Eight meta-analyses met the eligibility criteria: two including Level I studies only, five including both Level I and Level II studies, and one including additional Level III studies. Four meta-analyses found no differences between SR and DR RCR for patient outcomes, whereas four favored DR RCR for tears greater than 3 cm. Two meta-analyses found no structural healing differences between SR and DR RCR, whereas six found DR repair to be superior for tears greater than 3 cm tears. Conclusion: No clinical differences are seen between single-row and double-row repair for small and medium rotator cuff tears after a short-term follow-up period with a higher re-tear rate following single-row repairs. There seems to be a trend to superior results with double-row repair in large to massive tear sizes. PMID:27708735

  13. Investigation of bacterial nucleotide excision repair using single-molecule techniques

    PubMed Central

    Van Houten, Bennett; Kad, Neil

    2016-01-01

    Despite three decades of biochemical and structural analysis of the prokaryotic nucleotide excision repair (NER) system, many intriguing questions remain with regard to how the UvrA, UvrB, and UvrC proteins detect, verify and remove a wide range of DNA lesions. Single-molecule techniques have begun to allow more detailed understanding of the kinetics and action mechanism of this complex process. This article reviews how atomic force microscopy and fluorescence microscopy have captured new glimpses of how these proteins work together to mediate NER. PMID:24472181

  14. Laparoendoscopic single site surgery for extravesical repair of vesicovaginal fistula using conventional instruments: Our initial experience

    PubMed Central

    Mahadevappa, Nagabhushana; Gudage, Swathi; Senguttavan, Karthikeyan V.; Mallya, Ashwin; Dharwadkar, Sachin

    2016-01-01

    Objective: Vesicovaginal fistula (VVF) is a major complication with psychosocial ramifications. In literature, few VVF cases have been managed by laparoendoscopic single site surgery (LESS) and for the 1st time we report VVF repair by LESS using conventional laparoscopic instruments. We present our initial experience and to assess its feasibility, safety and outcome. Patients and Methods: From March 2012 to September 2015, LESS VVF repair was done for ten patients aged between 30 and 65 (45.6 ± 10.15) years, who presented with supratrigonal VVF. LESS was performed by modified O’Conor technique using regular trocars with conventional instruments. Data were collected regarding feasibility, intra- or post-operative pain, analgesic requirement, complication, and recovery. Results: All 10 cases were completed successfully, without conversion to a standard laparoscopic or open approach. The mean operative time was 182.5 ± 32.25 (150–250) min. The mean blood loss was 100 mL. The respective mean visual analog score for pain on day 1, 2, and 3 was 9.2 ± 1, 5 ± 1, and 1.4 ± 2.3. The analgesic requirement in the form of intravenous tramadol on days 1, 2, and 3 was 160 ± 51.6, 80 ± 63.2, and 30 ± 48.3, mgs respectively. No major intra- or post-operative complications were observed. The mean hospital stay was 2.6 ± 0.7 (2–4) days. Conclusion: In select patients, LESS extravesical repair of VVF using conventional laparoscopic instruments is safe, feasible with all the advantages of single port surgery at no added cost. Additional experience and comparative studies with conventional laparoscopy are warranted. PMID:27453652

  15. SUMO modification of the neuroprotective protein TDP1 facilitates chromosomal single-strand break repair

    PubMed Central

    Hudson, Jessica J.R.; Chiang, Shih-Chieh; Wells, Owen S.; Rookyard, Chris; El-Khamisy, Sherif F.

    2012-01-01

    Breaking and sealing one strand of DNA is an inherent feature of chromosome metabolism to overcome torsional barriers. Failure to reseal broken DNA strands results in protein-linked DNA breaks, causing neurodegeneration in humans. This is typified by defects in tyrosyl DNA phosphodiesterase 1 (TDP1), which removes stalled topoisomerase 1 peptides from DNA termini. Here we show that TDP1 is a substrate for modification by the small ubiquitin-like modifier SUMO. We purify SUMOylated TDP1 from mammalian cells and identify the SUMOylation site as lysine 111. While SUMOylation exhibits no impact on TDP1 catalytic activity, it promotes its accumulation at sites of DNA damage. A TDP1 SUMOylation-deficient mutant displays a reduced rate of repair of chromosomal single-strand breaks arising from transcription-associated topoisomerase 1 activity or oxidative stress. These data identify a role for SUMO during single-strand break repair, and suggest a mechanism for protecting the nervous system from genotoxic stress. PMID:22415824

  16. Laparoscopic Single Site Surgery for Repair of Retrocaval Ureter in a Morbidly Obese Patient

    PubMed Central

    Abdel-Karim, Aly M.; Yahia, Elsayed; Hassouna, M.; Missiry, M.

    2015-01-01

    This is to describe a case of a morbidly obese (BMI = 40) female with retrocaval ureter treated with laparoendoscopic single-site surgery. A JJ stent was positioned. A 2 cm umbilical access was created. A single port platform was positioned. The entire ureter was mobilized posterior to the vena cava and transected where the dilated portion ended. The distal ureter was repositioned lateral to the inferior vena cava. Anastomosis was done. A 3 mm trocar was used to assist suturing. At 4-month follow-up, CT revealed no evidence of obstruction of the right kidney and the patient was symptomless. Although challenging, in a morbidly obese patient, LESS repair for retrocaval ureter is feasible. PMID:26793585

  17. Endovascular Repair of Traumatic Rupture of the Thoracic Aorta: Single-Center Experience

    SciTech Connect

    Saratzis, Nikolaos A. Saratzis, Athanasios N.; Melas, Nikolaos; Ginis, Georgios; Lioupis, Athanasios; Lykopoulos, Dimitrios; Lazaridis, John; Dimitrios, Kiskinis

    2007-06-15

    Purpose. Traumatic rupture of the thoracic aorta secondary to blunt chest trauma is a life-threatening emergency and a common cause of death, usually following violent collisions. The objective of this retrospective report was to evaluate the efficacy of endovascular treatment of thoracic aortic disruptions with a single commercially available stent-graft. Methods. Nine men (mean age 29.5 years) were admitted to our institution between January 2003 and January 2006 due to blunt aortic trauma following violent motor vehicle collisions. Plain chest radiography, spiral computed tomography, aortography, and transesophageal echocardiography were used for diagnostic purposes in all cases. All patients were diagnosed with contained extramural thoracic aortic hematomas, secondary to aortic disruption. One patient was also diagnosed with a traumatic thoracic aortic dissection, secondary to blunt trauma. All subjects were poor surgical candidates, due to major injuries such as multiple bone fractures, abdominal hematomas, and pulmonary contusions. All repairs were performed using the EndoFit (LeMaitre Vascular) stent-graft. Results. Complete exclusion of the traumatic aortic disruption and pseudoaneurysm was achieved and verified at intraoperative arteriography and on CT scans, within 10 days of the repair in all patients. In 1 case the deployment of a second cuff was necessary due to a secondary endoleak. In 2 cases the left subclavian artery was occluded to achieve adequate graft fixation. No procedure-related deaths have occurred and no cardiac or peripheral vascular complications were observed within the 12 months (range 8-16 months) follow-up. Conclusions. This is the first time the EndoFit graft has been utilized in the treatment of thoracic aortic disruptions secondary to chest trauma. The repair of such pathologies is technically feasible and early follow-up results are promising.

  18. Different Cold Spray Deposition Strategies: Single- and Multi-layers to Repair Aluminium Alloy Components

    NASA Astrophysics Data System (ADS)

    Rech, Silvano; Trentin, Andrea; Vezzù, Simone; Vedelago, Enrico; Legoux, Jean-Gabriel; Irissou, Eric

    2014-12-01

    Cold spraying is increasingly being used for reconstruction or repair of damaged aluminium alloy components, especially in the aviation industry. Both thin (<0.5 mm) and thick (up to 1 cm) coatings are necessary to achieve dimensional recovery of such components. Thin and above all thick coatings can be deposited in a single pass (single layer) or in several passes (multi-pass), resulting in different thermal and stress effects in the component and the coating itself. The thermal input, the amount and type of residual stresses and the porosity affect various characteristics such as adhesion, crack propagation and mechanical properties of the coating. In this study, two sets (single- and multi-pass) of aluminium alloy (AA6061) coatings with different thicknesses (0.5 mm to 2 mm) were deposited onto AA6061 substrates and compared using metallographic and fractographic analyses, four-point bending testing, residual stress analysis and Vickers microhardness indentation. Finally, the coating adhesion and cohesion were measured using the standard ASTM-C633 adhesion test and tubular coating tensile test. This study demonstrates that the single-layer strategy results in greater adhesion and lower porosity, while multilayer coatings have higher elastic modulus. Independent of the strategy, the compressive residual stress decreases as a function of coating thickness.

  19. Single Operation to Repair Multifocal Cerebrospinal Fluid Fistulae Following Gunshot Wound: A Case Report

    PubMed Central

    White-Dzuro, Gabrielle A.; Entezami, Pouya; Wanna, George; Russell, Paul; Chambless, Lola B.

    2016-01-01

    Introduction Traumatic cerebrospinal fluid (CSF) fistulae can be a challenging neurosurgical disease, often requiring complicated surgical intervention. Case Presentation A 54-year-old man presented with a gunshot wound to the head with complex injury to the skull base and significant CSF leakage from multiple sites. A single surgery was performed using a combined Neurosurgery, Neurotology, and Rhinology team, which was successful in repairing the multiple skull base defects and preventing further CSF leak. Discussion Trauma to the skull base is a common inciting factor for the development of CSF fistulae. Endoscopic approaches are often preferred for repairing these defects, but craniotomy remains a viable option that may be required in more complex cases. A combined approach has not been described previously, but was successful for this severe multifocal defect. Conclusion A multidisciplinary approach allowed for a combined intervention that addressed both the anterior and middle fossae fistulae simultaneously. This limited the potential infectious complications of continued CSF leak and allowed for early rehabilitation. PMID:27330926

  20. Successful single-lung ventilation using a bronchial occluder for repair a large tracheoesophageal fistula: a case report

    PubMed Central

    Zhang, Lele; Zhao, Xiang; Li, Quan

    2015-01-01

    A 25-year-old girl was found a large tracheoesophageal fistula (TEF) 20 cm away from the incisors by gastroscope. It was a consequence of prolong intubation after the head operation because of right temporal lobe cerebral hemorrhage broken into ventricles. The patient was tracheotomy and retained spontaneous breathing. Operation was planned to via cervical and thoracic abdominal esophageal transection plus cervical esophagogastrostomy to repair the fistula under single lung ventilation under general anesthesia. Here we report a successful case using an endotracheal tube (EET) combine with a bronchial occluder for single ventilation to repair a large TEF. PMID:26550434

  1. A novel structure of DNA repair protein RecO from Deinococcus radiodurans.

    PubMed

    Makharashvili, Nodar; Koroleva, Olga; Bera, Sibes; Grandgenett, Duane P; Korolev, Sergey

    2004-10-01

    Recovery of arrested replication requires coordinated action of DNA repair, replication, and recombination machineries. Bacterial RecO protein is a member of RecF recombination repair pathway important for replication recovery. RecO possesses two distinct activities in vitro, closely resembling those of eukaryotic protein Rad52: DNA annealing and RecA-mediated DNA recombination. Here we present the crystal structure of the RecO protein from the extremely radiation resistant bacteria Deinococcus radiodurans (DrRecO) and characterize its DNA binding and strand annealing properties. The RecO structure is totally different from the Rad52 structure. DrRecO is comprised of three structural domains: an N-terminal domain which adopts an OB-fold, a novel alpha-helical domain, and an unusual zinc-binding domain. Sequence alignments suggest that the multidomain architecture is conserved between RecO proteins from other bacterial species and is suitable to elucidate sites of protein-protein and DNA-protein interactions necessary for RecO functions during the replication recovery and DNA repair. PMID:15458636

  2. Analysis of BRCA1 Variants in Double-Strand Break Repair by Homologous Recombination and Single-Strand Annealing

    PubMed Central

    Towler, William I.; Zhang, Jie; Ransburgh, Derek J. R.; Toland, Amanda E.; Ishioka, Chikashi; Chiba, Natsuko; Parvin, Jeffrey D.

    2014-01-01

    Missense substitutions of uncertain clinical significance in the BRCA1 gene are a vexing problem in genetic counseling for women who have a family history of breast cancer. In this study, we evaluated the functions of 29 missense substitutions of BRCA1 in two DNA repair pathways. Repair of double-strand breaks by homology-directed recombination (HDR) had been previously analyzed for 16 of these BRCA1 variants, and 13 more variants were analyzed in this study. All 29 variants were also analyzed for function in double-strand break repair by the single-strand annealing (SSA) pathway. We found that among the pathogenic mutations in BRCA1, all were defective for DNA repair by either pathway. The HDR assay was accurate because all pathogenic mutants were defective for HDR, and all nonpathogenic variants were fully functional for HDR. Repair by SSA accurately identified pathogenic mutants, but several nonpathogenic variants were scored as defective or partially defective. These results indicated that specific amino acid residues of the BRCA1 protein have different effects in the two related DNA repair pathways, and these results validate the HDR assay as highly correlative with BRCA1-associated breast cancer. PMID:23161852

  3. Functions of single-strand DNA-binding proteins in DNA replication, recombination, and repair.

    PubMed

    Marceau, Aimee H

    2012-01-01

    Double-stranded (ds) DNA contains all of the necessary genetic information, although practical use of this information requires unwinding of the duplex DNA. DNA unwinding creates single-stranded (ss) DNA intermediates that serve as templates for myriad cellular functions. Exposure of ssDNA presents several problems to the cell. First, ssDNA is thermodynamically less stable than dsDNA, which leads to spontaneous formation of duplex secondary structures that impede genome maintenance processes. Second, relative to dsDNA, ssDNA is hypersensitive to chemical and nucleolytic attacks that can cause damage to the genome. Cells deal with these potential problems by encoding specialized ssDNA-binding proteins (SSBs) that bind to and stabilize ssDNA structures required for essential genomic processes. SSBs are essential proteins found in all domains of life. SSBs bind ssDNA with high affinity and in a sequence-independent manner and, in doing so, SSBs help to form the central nucleoprotein complex substrate for DNA replication, recombination, and repair processes. While SSBs are found in every organism, the proteins themselves share surprisingly little sequence similarity, subunit composition, and oligomerization states. All SSB proteins contain at least one DNA-binding oligonucleotide/oligosaccharide binding (OB) fold, which consists minimally of a five stranded beta-sheet arranged as a beta barrel capped by a single alpha helix. The OB fold is responsible for both ssDNA binding and oligomerization (for SSBs that operate as oligomers). The overall organization of OB folds varies between bacteria, eukaryotes, and archaea. As part of SSB/ssDNA cellular structures, SSBs play direct roles in the DNA replication, recombination, and repair. In many cases, SSBs have been found to form specific complexes with diverse genome maintenance proteins, often helping to recruit SSB/ssDNA-processing enzymes to the proper cellular sites of action. This clustering of genome maintenance

  4. The self-construction and -repair of a foraging organism by explicitly specified development from a single cell.

    PubMed

    Roth, Fabian; Siegelmann, Hava; Douglas, Rodney J

    2007-01-01

    As man-made systems become more complex and autonomous, there is a growing need for novel engineering methods that offer self-construction, adaptation to the environment, and self-repair. In a step towards developing such methods, we demonstrate how a simple model multicellular organism can assemble itself by replication from a single cell and finally express a fundamental behavior: foraging. Previous studies have employed evolutionary approaches to this problem. Instead, we aim at explicit design of self-constructing and -repairing systems by hierarchical specification of elementary intracellular mechanisms via a kind of genetic code. The interplay between individual cells and the gradually increasing self-created complexity of the local structure that surrounds them causes the serial unfolding of the final functional organism. The developed structure continuously feeds back to the development process, and so the system is also capable of self-repair. PMID:17716016

  5. CK2 phosphorylation of XRCC1 facilitates dissociation from DNA and single-strand break formation during base excision repair.

    PubMed

    Ström, Cecilia E; Mortusewicz, Oliver; Finch, David; Parsons, Jason L; Lagerqvist, Anne; Johansson, Fredrik; Schultz, Niklas; Erixon, Klaus; Dianov, Grigory L; Helleday, Thomas

    2011-09-01

    CK2 phosphorylates the scaffold protein XRCC1, which is required for efficient DNA single-strand break (SSB) repair. Here, we express an XRCC1 protein (XRCC1(ckm)) that cannot be phosphorylated by CK2 in XRCC1 mutated EM9 cells and show that the role of this post-translational modification gives distinct phenotypes in SSB repair and base excision repair (BER). Interestingly, we find that fewer SSBs are formed during BER after treatment with the alkylating agent dimethyl sulfate (DMS) in EM9 cells expressing XRCC1(ckm) (CKM cells) or following inhibition with the CK2 inhibitor 2-dimethylamino-4,5,6,7-tetrabromo-1H-benzimidazole (DMAT). We also show that XRCC1(ckm) protein has a higher affinity for DNA than wild type XRCC1 protein and resides in an immobile fraction on DNA, in particular after damage. We propose a model whereby the increased affinity for DNA sequesters XRCC1(ckm) and the repair enzymes associated with it, at the repair site, which retards kinetics of BER. In conclusion, our results indicate that phosphorylation of XRCC1 by CK2 facilitates the BER incision step, likely by promoting dissociation from DNA.

  6. Oxidative Stress and Plasma Membrane Repair in Single Myoblasts After Femtosecond Laser Photoporation.

    PubMed

    Duan, Xinxing; Chan, Kam Tai; Lee, Kenneth K H; Mak, Arthur F T

    2015-11-01

    Cell membranes are susceptible to biophysical damages. These biophysical damages often present themselves in challenging oxidative environments, such as in chronic inflammation. Here we report the damage evolution after single myoblasts were individually subjected to femtosecond (fs) laser photoporation on their plasma membranes under normal and oxidative conditions. A well-characterized tunable fs laser was coupled with a laser scanning confocal microscope. The post-damage wound evolution was documented by real-time imaging. The fs laser could generate a highly focused hole at a targeted site of the myoblast plasma membrane. The initial hole size depended on the laser dosage in terms of power and exposure duration. With the same laser power and irradiation duration, photoporation invoked bigger holes in the oxidative groups than in the control. Myoblasts showed difficulty in repairing holes with initial size beyond certain threshold. Within the threshold, holes could apparently be resealed within 100 s under the normal condition; while in oxidative condition, the resealing process could take 100-300 s. The hole-resealing capacity of myoblasts was compromised under oxidative stress particularly when the oxidative exposure was chronic. It is interesting to note that brief exposure to oxidative stress apparently could promote resealing in myoblasts after photoporation. PMID:26014361

  7. Optimal single-replacement for repairable products with different failure rate under a finite planning horizon

    NASA Astrophysics Data System (ADS)

    Chang, Wen Liang

    2015-04-01

    This paper provides a replacement policy for repairable products with free-repair warranty (FRW) under a finite planning horizon from the consumer's viewpoint. Assume that the product is replaced once within a finite planning horizon, and the failure rate of the second product is lower than the failure rate of the first product. Within FRW, the failed product is corrected by minimal repair without any cost to the consumers. After FRW, the failed product is repaired with a fixed repair cost to the consumers. However, each failure incurs a fixed downtime cost to the consumers over a finite planning horizon. In this paper, we derive the three models of the expected total disbursement cost within a finite planning horizon and some properties of the optimal replacement policy under some reasonable conditions are obtained. Finally, numerical examples are given to illustrate the features of the optimal replacement policy under various maintenance costs.

  8. Single nucleotide polymorphisms in nucleotide excision repair genes, cancer treatment, and head and neck cancer survival

    PubMed Central

    Wyss, Annah B.; Weissler, Mark C.; Avery, Christy L.; Herring, Amy H.; Bensen, Jeannette T.; Barnholtz-Sloan, Jill S.; Funkhouser, William K.

    2014-01-01

    Purpose Head and neck cancers (HNC) are commonly treated with radiation and platinum-based chemotherapy, which produce bulky DNA adducts to eradicate cancerous cells. Because nucleotide excision repair (NER) enzymes remove adducts, variants in NER genes may be associated with survival among HNC cases both independently and jointly with treatment. Methods Cox proportional hazards models were used to estimate race-stratified (White, African American) hazard ratios (HRs) and 95 % confidence intervals for overall (OS) and disease-specific (DS) survival based on treatment (combinations of surgery, radiation, and chemotherapy) and 84 single nucleotide polymorphisms (SNPs) in 15 NER genes among 1,227 HNC cases from the Carolina Head and Neck Cancer Epidemiology Study. Results None of the NER variants evaluated were associated with survival at a Bonferroni-corrected alpha of 0.0006. However, rs3136038 [OS HR = 0.79 (0.65, 0.97), DS HR = 0.69 (0.51, 0.93)] and rs3136130 [OS HR = 0.78 (0.64, 0.96), DS HR = 0.68 (0.50, 0.92)] of ERCC4 and rs50871 [OS HR = 0.80 (0.64, 1.00), DS HR = 0.67 (0.48, 0.92)] of ERCC2 among Whites, and rs2607755 [OS HR = 0.62 (0.45, 0.86), DS HR = 0.51 (0.30, 0.86)] of XPC among African Americans were suggestively associated with survival at an uncorrected alpha of 0.05. Three SNP-treatment joint effects showed possible departures from additivity among Whites. Conclusions Our study, a large and extensive evaluation of SNPs in NER genes and HNC survival, identified mostly null associations, though a few variants were suggestively associated with survival and potentially interacted additively with treatment. PMID:24487794

  9. Single-molecule motions and interactions in live cells reveal target search dynamics in mismatch repair

    PubMed Central

    Liao, Yi; Schroeder, Jeremy W.; Gao, Burke; Simmons, Lyle A.; Biteen, Julie S.

    2015-01-01

    MutS is responsible for initiating the correction of DNA replication errors. To understand how MutS searches for and identifies rare base-pair mismatches, we characterized the dynamic movement of MutS and the replisome in real time using superresolution microscopy and single-molecule tracking in living cells. We report that MutS dynamics are heterogeneous in cells, with one MutS population exploring the nucleoid rapidly, while another MutS population moves to and transiently dwells at the replisome region, even in the absence of appreciable mismatch formation. Analysis of MutS motion shows that the speed of MutS is correlated with its separation distance from the replisome and that MutS motion slows when it enters the replisome region. We also show that mismatch detection increases MutS speed, supporting the model for MutS sliding clamp formation after mismatch recognition. Using variants of MutS and the replication processivity clamp to impair mismatch repair, we find that MutS dynamically moves to and from the replisome before mismatch binding to scan for errors. Furthermore, a block to DNA synthesis shows that MutS is only capable of binding mismatches near the replisome. It is well-established that MutS engages in an ATPase cycle, which is necessary for signaling downstream events. We show that a variant of MutS with a nucleotide binding defect is no longer capable of dynamic movement to and from the replisome, showing that proper nucleotide binding is critical for MutS to localize to the replisome in vivo. Our results provide mechanistic insight into the trafficking and movement of MutS in live cells as it searches for mismatches. PMID:26575623

  10. Whole field strain measurement in critical thin adhesive layer of single- and double-sided repaired CFRP panel using DIC

    NASA Astrophysics Data System (ADS)

    Kashfuddoja, Mohammad; Ramji, M.

    2015-03-01

    In the present work, the behavior of thin adhesively layer in patch repaired carbon fiber reinforced polymer (CFRP) panel under tensile load is investigated experimentally using digital image correlation (DIC) technique. The panel is made of Carbon/epoxy composite laminate and the stacking sequence in the panel is [0º]4. A circular hole of 10 mm diameter (d) is drilled at the center of the panel to mimic the case of low velocity impact damage removal. The panel with open hole is repaired with double sided (symmetrical) and single sided (unsymmetrical) rectangular patch made of same panel material having stacking sequence of [0º]3. Araldite 2011 is used for bonding the patch onto the panel over the damaged area. The global behavior of thin adhesive layer is examined by analyzing whole field strain distribution using DIC. Longitudinal, peel and shear strain field in both double and single sided repair configuration is studied and a compression is made between them. An estimate of shear transfer length which is an essential parameter in arriving at an appropriate overlap length in patch design is proposed from DIC and FEA. Damage development, failure mechanism and load displacement behavior is also investigated. The experimental results are compared with the numerical predictions.

  11. Repair of Radiation-Induced Damage in Escherichia coli II. Effect of rec and uvr Mutations on Radiosensitivity, and Repair of X-Ray-Induced Single-Strand Breaks in Deoxyribonucleic Acid1

    PubMed Central

    Kapp, Daniel S.; Smith, Kendric C.

    1970-01-01

    Strains of Escherichia coli K-12 mutant in the genes controlling excision repair (uvr) and genetic recombination (rec) have been studied with reference to their radiosensitivity and their ability to repair X-ray-induced single-strand breaks in deoxyribonucleic acid (DNA). Mutations in the rec genes appreciably increase the radiosensitivity of E. coli K-12, whereas uvr mutations produce little if any increase in radiosensitivity. For a given dose of X-rays, the yield of single-strand breaks has been shown by alkaline sucrose gradient studies to be largely independent of the presence of rec or uvr mutations. The rec+ cells (including those carrying the uvrB5 mutation) could efficiently rejoin X-ray-induced single-strand breaks in DNA, whereas recA56 mutants could not repair these breaks to any great extent. The recB21 and recC22 mutants showed some indication of repair capacity. From these studies, it is concluded that a correlation exists between the inability to repair single-strand breaks and the radiosensitivity of the rec mutants of E. coli K-12. This suggests that unrepaired single-strand breaks may be lethal lesions in E. coli. PMID:4912530

  12. Distinctive features of single nucleotide alterations in induced pluripotent stem cells with different types of DNA repair deficiency disorders

    PubMed Central

    Okamura, Kohji; Sakaguchi, Hironari; Sakamoto-Abutani, Rie; Nakanishi, Mahito; Nishimura, Ken; Yamazaki-Inoue, Mayu; Ohtaka, Manami; Periasamy, Vaiyapuri Subbarayan; Alshatwi, Ali Abdullah; Higuchi, Akon; Hanaoka, Kazunori; Nakabayashi, Kazuhiko; Takada, Shuji; Hata, Kenichiro; Toyoda, Masashi; Umezawa, Akihiro

    2016-01-01

    Disease-specific induced pluripotent stem cells (iPSCs) have been used as a model to analyze pathogenesis of disease. In this study, we generated iPSCs derived from a fibroblastic cell line of xeroderma pigmentosum (XP) group A (XPA-iPSCs), a rare autosomal recessive hereditary disease in which patients develop skin cancer in the areas of skin exposed to sunlight. XPA-iPSCs exhibited hypersensitivity to ultraviolet exposure and accumulation of single-nucleotide substitutions when compared with ataxia telangiectasia-derived iPSCs that were established in a previous study. However, XPA-iPSCs did not show any chromosomal instability in vitro, i.e. intact chromosomes were maintained. The results were mutually compensating for examining two major sources of mutations, nucleotide excision repair deficiency and double-strand break repair deficiency. Like XP patients, XPA-iPSCs accumulated single-nucleotide substitutions that are associated with malignant melanoma, a manifestation of XP. These results indicate that XPA-iPSCs may serve a monitoring tool (analogous to the Ames test but using mammalian cells) to measure single-nucleotide alterations, and may be a good model to clarify pathogenesis of XP. In addition, XPA-iPSCs may allow us to facilitate development of drugs that delay genetic alteration and decrease hypersensitivity to ultraviolet for therapeutic applications. PMID:27197874

  13. [Nonhomologous mechanisms of repair of chromosomal breaks]. Progress report

    SciTech Connect

    Haber, J.E.

    1993-09-01

    Broken chromosomes must either be repaired or lost. The break separates part of the chromosome, containing a telomere, from the rest, containing a centromere. While the centromerecontaining fragment can properly segregate, the broken end will be progressively degraded. The acentric fragment cannot segregate and will also be degraded. We have centered our attention on two alternative non-homologous mechanisms of repair: (1) the acquisition of a new telomere, and (2) repair of broken chromosomes by non-homologous joining of broken chromosome ends. In both cases, we create a double-strand break at a defined chromosomal location in yeast cells. The break is created by the site-specific HO endonuclease in cells that carry the rad52 mutation to prevent repair of a double-strand break by homologous recombination. In diploid cells, we can recover cells that contain a terminally deleted, healed chromosome that has acquired a new telomere. In haploid cells, we can recover cells in which the double-strand break has been repaired by rejoining the broken ends, usually accompanied by a deletion.

  14. Repair of adjacent single-strand breaks is often accompanied by the formation of tandem sequence duplications in plant genomes.

    PubMed

    Schiml, Simon; Fauser, Friedrich; Puchta, Holger

    2016-06-28

    Duplication of existing sequences is a major mechanism of genome evolution. It has been previously shown that duplications can occur by replication slippage, unequal sister chromatid exchange, homologous recombination, and aberrant double-strand break-induced synthesis-dependent strand annealing reactions. In a recent study, the abundant presence of short direct repeats was documented by comparative bioinformatics analysis of different rice genomes, and the hypothesis was put forward that such duplications might arise due to the concerted repair of adjacent single-strand breaks (SSBs). Applying the CRISPR/Cas9 technology, we were able to test this hypothesis experimentally in the model plant Arabidopsis thaliana Using a Cas9 nickase to induce adjacent genomic SSBs in different regions of the genome (genic, intergenic, and heterochromatic) and at different distances (∼20, 50, and 100 bps), we analyzed the repair outcomes by deep sequencing. In addition to deletions, we regularly detected the formation of direct repeats close to the break sites, independent of the genomic context. The formation of these duplications as well as deletions may be associated with the presence of microhomologies. Most interestingly, we found that even the induction of two SSBs on the same DNA strand can cause genome alterations, albeit at a much lower level. Because such a scenario reflects a natural step during nucleotide excision repair, and given that the germline is set aside only late during development in plants, the repair of adjacent SSBs indeed seems to have an important influence on the shaping of plant genomes during evolution. PMID:27307441

  15. Transthoracic single port with peroral assistance: an animal experiment to assess a less invasive technique for human esophageal atresia repair.

    PubMed

    Henriques-Coelho, Tiago; Soares, Tony R; Miranda, Alice; Moreira-Pinto, João; Correia-Pinto, Jorge

    2012-12-01

    Thoracoscopic repair of esophageal atresia has becoming the gold standard in many centers because it allows a better cosmetic result and avoids the musculoskeletal sequelae of a thoracotomy. Natural orifice translumenal endocopic surgery (NOTES) is a new surgical paradigm, and its human application has already been started in some procedures. In the present study, we explore the feasibility of performing an esophagoesophageal anastomosis using a single transthoracic single port combined with a peroral access in a rabbit model to simulate repair of esophageal atresia by hybrid NOTES in a human newborn. Adult male rabbits (Oryctolagus cuniculus, n=28) were used to perform the surgical protocol. We used a transthoracic telescope with a 3-mm working channel and a flexible endoscope with a 2.2-mm working channel by peroral access. We performed total esophagotomy with peroral scissors followed by an esophagoesophageal anastomosis achieved with a rigid transthoracic scope helped by the peroral operator. Extracorporeal transthoracic knots were performed to complete the anastomosis. The anastomoses were examined in loco and ex loco, after animal sacrifice. We successfully accomplished a complete esophageal anastomosis in all rabbits using a combination of transthoracic and peroral 3-mm instruments. This study provides important insights for a possible translation of hybrid NOTES to human newborns with esophageal atresia. Forward studies to accomplish their feasibility in human newborns will still be necessary.

  16. Long-term functional outcomes after bladder exstrophy repair: A single, low-volume centre experience

    PubMed Central

    Alsowayan, Ossamah; Capolicchio, John Paul; Jednak, Roman; El-Sherbiny, Mohamed

    2016-01-01

    Introduction: In this study, we present our experience managing bladder exstrophy (BE) in a low-volume centre over 24 years. Methods: Charts of patients with BE between 1990 and 2014 were retrospectively reviewed. Patients with BE closure and ≥5 years followup were included. BE closure was carried out in the first two days of life using either complete primary repair (CPRE) or modern-staged repair (MSRE). Daytime urinary continence (UC) was evaluated by the age of five years. Patients were considered continent if completely dry for ≥3 hours using no or one pad/day. Incontinent patients with bladder capacity (BC) ≥100 ml underwent bladder neck reconstruction (BNR) and bilateral ureteric reimplantation (BUR), while patients with BC <100ml underwent simultaneous augmentation cystoplasty (ACP). Results: Sixteen (16) patients met our inclusion criteria with a mean followup time of 18±5 years. Ten (10) underwent CPRE, while six underwent MSRE. Four surgeons were involved in patients’ management. Two surgeons had previous experience in BE surgery while working in other institutions. Complications included dehiscence in five patients, vesicocutanous fistula in three and breakthrough UTI in eight. Continence was achieved in 15/16 patients: two after BE closure only, seven with BNR, and six who required ACP and BNR. Conclusions: Despite the small number of patients and the reterospective nature of the study, some observations are noteworthy. Although continence rate post-primary BE closure was initially low, it rose to 93.8% after auxiliary continence procedures. This might be at the cost of urethral voiding, which was achieved in 60% of patients. Our small cohort did not show clear advantage of CPRE vs. MSRE. Our outcomes may not be different from high-volume centres due to the fact that two exstrophy-experienced surgeons performed most primary or subsequent surgeries. For this reason, we recommend assigning designated centres for BE repair for both new and repeat

  17. Outcomes of Surgical Repair for Persistent Truncus Arteriosus from Neonates to Adults: A Single Center's Experience

    PubMed Central

    Chen, Qiuming; Gao, Huawei; Hua, Zhongdong; Yang, Keming; Yan, Jun; Zhang, Hao; Ma, Kai; Zhang, Sen; Qi, Lei; Li, Shoujun

    2016-01-01

    Objective This study aimed to report our experiences with surgical repair in patients of all ages with persistent truncus arteriosus. Methods From July 2004 to July 2014, 50 consecutive patients with persistent truncus arteriosus who underwent anatomical repair were included in the retrospective review. Median follow-up time was 3.4 years (range, 3 months to 10 years). Results Fifty patients underwent anatomical repair at a median age of 19.6 months (range, 20 days to 19.1 years). Thirty patients (60%) were older than one year. The preoperative pulmonary vascular resistance and mean pulmonary artery pressure were 4.1±2.1 (range, 0.1 to 8.9) units.m2 and 64.3±17.9 (range, 38 to 101) mmHg, respectively. Significant truncal valve regurgitation was presented in 14 (28%) patients. Hospital death occurred in 3 patients, two due to pulmonary hypertensive crisis and the other due to pneumonia. Three late deaths occurred at 3, 4 and 11 months after surgery. The actuarial survival rates were 87.7% and 87.7% at 1 year and 5 years, respectively. Multivariate analysis identified significant preoperative truncal valve regurgitation was a risk factor for overall mortality (odds ratio, 7.584; 95%CI: 1.335–43.092; p = 0.022). Two patients required reoperation of truncal valve replacement. One patient underwent reintervention for conduit replacement. Freedom from reoperation at 5 years was 92.9%. At latest examination, there was one patient with moderate-to-severe truncal valve regurgitation and four with moderate. Three patients had residual pulmonary artery hypertension. All survivors were in New York Heart Association class I-II. Conclusions Complete repair of persistent truncus arteriosus can be achieved with a relatively low mortality and acceptable early- and mid-term results, even in cases with late presentation. Significant preoperative truncal valve regurgitation remains a risk factor for overall mortality. The long-term outcomes warrant further follow-up. PMID:26752522

  18. QUANTITATION OF INTRACELLULAR NAD(P)H IN LIVING CELLS CAN MONITOR AN IMBALANCE OF DNA SINGLE STRAND BREAK REPAIR IN REAL TIME

    EPA Science Inventory

    Quantitation of intracellular NAD(P)H in living cells can monitor an imbalance of DNA single strand break repair in real time.

    ABSTRACT

    DNA single strand breaks (SSBs) are one of the most frequent DNA lesions in genomic DNA generated either by oxidative stress or du...

  19. Topoisomerase 1 and single-strand break repair modulate transcription-induced CAG repeat contraction in human cells.

    PubMed

    Hubert, Leroy; Lin, Yunfu; Dion, Vincent; Wilson, John H

    2011-08-01

    Expanded trinucleotide repeats are responsible for a number of neurodegenerative diseases, such as Huntington disease and myotonic dystrophy type 1. The mechanisms that underlie repeat instability in the germ line and in the somatic tissues of human patients are undefined. Using a selection assay based on contraction of CAG repeat tracts in human cells, we screened the Prestwick chemical library in a moderately high-throughput assay and identified 18 novel inducers of repeat contraction. A subset of these compounds targeted pathways involved in the management of DNA supercoiling associated with transcription. Further analyses using both small molecule inhibitors and small interfering RNA (siRNA)-mediated knockdowns demonstrated the involvement of topoisomerase 1 (TOP1), tyrosyl-DNA phosphodiesterase 1 (TDP1), and single-strand break repair (SSBR) in modulating transcription-dependent CAG repeat contractions. The TOP1-TDP1-SSBR pathway normally functions to suppress repeat instability, since interfering with it stimulated repeat contractions. We further showed that the increase in repeat contractions when the TOP1-TDP1-SSBR pathway is compromised arises via transcription-coupled nucleotide excision repair, a previously identified contributor to transcription-induced repeat instability. These studies broaden the scope of pathways involved in transcription-induced CAG repeat instability and begin to define their interrelationships. PMID:21628532

  20. Segmental Duplications Arise from Pol32-Dependent Repair of Broken Forks through Two Alternative Replication-Based Mechanisms

    PubMed Central

    Dujon, Bernard; Fischer, Gilles

    2008-01-01

    The propensity of segmental duplications (SDs) to promote genomic instability is of increasing interest since their involvement in numerous human genomic diseases and cancers was revealed. However, the mechanism(s) responsible for their appearance remain mostly speculative. Here, we show that in budding yeast, replication accidents, which are most likely transformed into broken forks, play a causal role in the formation of SDs. The Pol32 subunit of the major replicative polymerase Polδ is required for all SD formation, demonstrating that SDs result from untimely DNA synthesis rather than from unequal crossing-over. Although Pol32 is known to be required for classical (Rad52-dependant) break-induced replication, only half of the SDs can be attributed to this mechanism. The remaining SDs are generated through a Rad52-independent mechanism of template switching between microsatellites or microhomologous sequences. This new mechanism, named microhomology/microsatellite-induced replication (MMIR), differs from all known DNA double-strand break repair pathways, as MMIR-mediated duplications still occur in the combined absence of homologous recombination, microhomology-mediated, and nonhomologous end joining machineries. The interplay between these two replication-based pathways explains important features of higher eukaryotic genomes, such as the strong, but not strict, association between SDs and transposable elements, as well as the frequent formation of oncogenic fusion genes generating protein innovations at SD junctions. PMID:18773114

  1. Analyses of point mutation repair and allelic heterogeneity generated by CRISPR/Cas9 and single-stranded DNA oligonucleotides.

    PubMed

    Bialk, Pawel; Sansbury, Brett; Rivera-Torres, Natalia; Bloh, Kevin; Man, Dula; Kmiec, Eric B

    2016-09-09

    The repair of a point mutation can be facilitated by combined activity of a single-stranded oligonucleotide and a CRISPR/Cas9 system. While the mechanism of action of combinatorial gene editing remains to be elucidated, the regulatory circuitry of nucleotide exchange executed by oligonucleotides alone has been largely defined. The presence of the appropriate CRISPR/Cas9 system leads to an enhancement in the frequency of gene editing directed by single-stranded DNA oligonucleotides. While CRISPR/Cas9 executes double-stranded DNA cleavage efficiently, closure of the broken chromosomes is dynamic, as varying degrees of heterogeneity of the cleavage products appear to accompany the emergence of the corrected base pair. We provide a detailed analysis of allelic variance at and surrounding the target site. In one particular case, we report sequence alteration directed by a distinct member of the same gene family. Our data suggests that single-stranded DNA molecules may influence DNA junction heterogeneity created by CRISPR/Cas9.

  2. Analyses of point mutation repair and allelic heterogeneity generated by CRISPR/Cas9 and single-stranded DNA oligonucleotides.

    PubMed

    Bialk, Pawel; Sansbury, Brett; Rivera-Torres, Natalia; Bloh, Kevin; Man, Dula; Kmiec, Eric B

    2016-01-01

    The repair of a point mutation can be facilitated by combined activity of a single-stranded oligonucleotide and a CRISPR/Cas9 system. While the mechanism of action of combinatorial gene editing remains to be elucidated, the regulatory circuitry of nucleotide exchange executed by oligonucleotides alone has been largely defined. The presence of the appropriate CRISPR/Cas9 system leads to an enhancement in the frequency of gene editing directed by single-stranded DNA oligonucleotides. While CRISPR/Cas9 executes double-stranded DNA cleavage efficiently, closure of the broken chromosomes is dynamic, as varying degrees of heterogeneity of the cleavage products appear to accompany the emergence of the corrected base pair. We provide a detailed analysis of allelic variance at and surrounding the target site. In one particular case, we report sequence alteration directed by a distinct member of the same gene family. Our data suggests that single-stranded DNA molecules may influence DNA junction heterogeneity created by CRISPR/Cas9. PMID:27609304

  3. Analyses of point mutation repair and allelic heterogeneity generated by CRISPR/Cas9 and single-stranded DNA oligonucleotides

    PubMed Central

    Bialk, Pawel; Sansbury, Brett; Rivera-Torres, Natalia; Bloh, Kevin; Man, Dula; Kmiec, Eric B.

    2016-01-01

    The repair of a point mutation can be facilitated by combined activity of a single-stranded oligonucleotide and a CRISPR/Cas9 system. While the mechanism of action of combinatorial gene editing remains to be elucidated, the regulatory circuitry of nucleotide exchange executed by oligonucleotides alone has been largely defined. The presence of the appropriate CRISPR/Cas9 system leads to an enhancement in the frequency of gene editing directed by single-stranded DNA oligonucleotides. While CRISPR/Cas9 executes double-stranded DNA cleavage efficiently, closure of the broken chromosomes is dynamic, as varying degrees of heterogeneity of the cleavage products appear to accompany the emergence of the corrected base pair. We provide a detailed analysis of allelic variance at and surrounding the target site. In one particular case, we report sequence alteration directed by a distinct member of the same gene family. Our data suggests that single-stranded DNA molecules may influence DNA junction heterogeneity created by CRISPR/Cas9. PMID:27609304

  4. Single cell analysis of human RAD18-dependent DNA post-replication repair by alkaline bromodeoxyuridine comet assay.

    PubMed

    Mórocz, Mónika; Gali, Himabindu; Raskó, István; Downes, C Stephen; Haracska, Lajos

    2013-01-01

    Damage to DNA can block replication progression resulting in gaps in the newly synthesized DNA. Cells utilize a number of post-replication repair (PRR) mechanisms such as the RAD18 controlled translesion synthesis or template switching to overcome the discontinuities formed opposite the DNA lesions and to complete DNA replication. Gaining more insights into the role of PRR genes promotes better understanding of DNA damage tolerance and of how their malfunction can lead to increased genome instability and cancer. However, a simple and efficient method to characterise gene specific PRR deficiencies at a single cell level has not been developed. Here we describe the so named BrdU comet PRR assay to test the contribution of human RAD18 to PRR at a single cell level, by which we kinetically characterized the consequences of the deletion of human RAD18 on the replication of UV-damaged DNA. Moreover, we demonstrate the capability of our method to evaluate PRR at a single cell level in unsynchronized cell population.

  5. A novel protein, Rsf1/Pxd1, is critical for the single-strand annealing pathway of double-strand break repair in Schizosaccharomyces pombe.

    PubMed

    Wang, Hanqian; Zhang, Zhanlu; Zhang, Lan; Zhang, Qiuxue; Zhang, Liang; Zhao, Yangmin; Wang, Weibu; Fan, Yunliu; Wang, Lei

    2015-06-01

    The process of single-strand annealing (SSA) repairs DNA double-strand breaks that are flanked by direct repeat sequences through the coordinated actions of a series of proteins implicated in recombination, mismatch repair and nucleotide excision repair (NER). Many of the molecular and mechanistic insights gained in SSA repair have principally come from studies in the budding yeast Saccharomyces cerevisiae. However, there is little molecular understanding of the SSA pathway in the fission yeast Schizosaccharomyces pombe. To further our understanding of this important process, we established a new chromosome-based SSA assay in fission yeast. Our genetic analyses showed that, although many homologous components participate in SSA repair in these species indicating that some evolutionary conservation, Saw1 and Slx4 are not principal agents in the SSA repair pathway in fission yeast. This is in marked contrast to the function of Saw1 and Slx4 in budding yeast. Additionally, a novel genus-specific protein, Rsf1/Pxd1, physically interacts with Rad16, Swi10 and Saw1 in vitro and in vivo. We find that Rsf1/Pxd1 is not required for NER and demonstrate that, in fission yeast, Rsf1/Pxd1, but not Saw1, plays a critical role in SSA recombination.

  6. Experience With Fenestrated Endovascular Repair of Juxtarenal Abdominal Aortic Aneurysms at a Single Center

    PubMed Central

    Hu, Zhongzhou; Li, Yue; Peng, Ran; Liu, Jie; Zhang, Tao; Guo, Wei

    2016-01-01

    Abstract To present the early and mid-term results of fenestrated endovascular aneurysm repair (FEVAR) using the Zenith fenestrated device for juxtarenal abdominal aortic aneurysms (JAAAs) at our center in China. Design: Retrospective study. The study included 15 male patients with JAAAs, who underwent FEVAR using the Zenith fenestrated device at our center between February 2011 and June 2015. All custom-made Zenith fenestrated devices were designed according to computed tomography angiography (CTA) images obtained preoperatively. The patients with renal insufficiency underwent duplex ultrasonography, while the patients with normal renal function underwent 3 CT data acquisitions including nonenhanced CT, arterial phase, and venous phase. These examinations and blood examinations were completed at 3, 6, and 12 months after discharge, and annually thereafter. The mean age of the patients was 73.13 ± 9.06 years (range, 57–86 years), and the median follow-up period was 30 months (8–52 months). Small fenestrations were used in 27 renal arteries, scallops were used in 7 superior mesenteric arteries (SMAs) and 2 renal arteries, and large fenestrations were used in 2 SMAs. Conversion to an open procedure was not required in any of the patients, and the technical success rate was 100%. The mean length of hospital stay was 11.33 ± 2.02 days (7–15 days). No patient died within the 1st 30 days after the operation. One patient had a type Ia endoleak, which disappeared at 6 months after the operation, 1 patient had a type Ib endoleak, which was detected at 17 months after the operation, and 2 patients had type II endoleaks. One patient died at 17 months and another patient died at 30 months after the operation. Therefore, the all-cause mortality rate was 13.33% (2/15). The target vessel patency rate was 100% without occlusion. The early and mid-term results of FEVAR using the Zenith fenestrated device were good, demonstrating that this procedure is effective for

  7. A Novel Single Pulsed Electromagnetic Field Stimulates Osteogenesis of Bone Marrow Mesenchymal Stem Cells and Bone Repair

    PubMed Central

    Chang, Je-Ken; Chen, Chung-Hwan; Tai, I-Chun; Wang, Gwo-Jaw; Ho, Mei-Ling

    2014-01-01

    Pulsed electromagnetic field (PEMF) has been successfully applied to accelerate fracture repair since 1979. Recent studies suggest that PEMF might be used as a nonoperative treatment for the early stages of osteonecrosis. However, PEMF treatment requires a minimum of ten hours per day for the duration of the treatment. In this study, we modified the protocol of the single-pulsed electromagnetic field (SPEMF) that only requires a 3-minute daily treatment. In the in vitro study, cell proliferation and osteogenic differentiation was evaluated in the hBMSCs. In the in vivo study, new bone formation and revascularization were evaluated in the necrotic bone graft. Results from the in vitro study showed no significant cytotoxic effects on the hBMSCs after 5 days of SPEMF treatment (1 Tesla, 30 pulses per day). hBMSC proliferation was enhanced in the SPEMF-treated groups after 2 and 4 days of treatment. The osteogenic differentiation of hBMSCs was significantly increased in the SPEMF-treated groups after 3–7 days of treatment. Mineralization also increased after 10, 15, 20, and 25 days of treatment in SPEMF-treated groups compared to the control group. The 7-day short-course treatment achieved similar effects on proliferation and osteogenesis as the 25-day treatment. Results from the in vivo study also demonstrated that both the 7-day and 25-day treatments of SPEMF increased callus formation around the necrotic bone and also increased new vessel formation and osteocyte numbers in the grafted necrotic bone at the 2nd and 4th weeks after surgery. In conclusion, the newly developed SPEMF accelerates osteogenic differentiation of cultured hBMSCs and enhances bone repair, neo-vascularization, and cell growth in necrotic bone in mice. The potential clinical advantage of the SPEMF is the short daily application and the shorter treatment course. We suggest that SPEMF may be used to treat fractures and the early stages of osteonecrosis. PMID:24632682

  8. Single-stage implantation in the atrophic alveolar ridge of the mandible with the Norian skeletal repair system.

    PubMed

    Hölzle, Frank; Bauer, Florian; Kesting, Marco R; Mücke, Thomas; Deppe, Herbert; Wolff, Klaus-Dietrich; Swaid, Sami

    2011-10-01

    Dental implants have played a part in rehabilitation of the jaws for more than 40 years, but in some cases they alone are inadequate because of extreme alveolar resorption. Correction may necessitate a two-stage procedure with additional interventions. We have made a preliminary study of the use of the Norian skeletal repair system (SRS), a carbonated calcium phosphate bone cement used to augment the alveolar ridge as a single-stage procedure, with the placement of implants. Ten edentulous patients with insufficient vertical bone in the interforaminal area were treated. After a horizontal osteotomy and crestal mobilisation of the alveolar ridge, implants were placed through the crestal part and fixed in the basal part of the mandible. Norian SRS was used to fill the gap created. The prostheses were inserted 3 months later. Forty implants were inserted. The follow up period was 60 months, and no fractures or dislocations developed. One of the implants was lost and there was one wound dehiscence, but no surgical intervention or revision was necessary. Radiographs showed good consolidation of the bony structure in all cases. We have described a reliable, single-stage procedure for augmentation and implantation in a highly atrophic alveolar crest. A 98% survival is comparable with those of other techniques. Further clinical trials are necessary to replicate these promising results.

  9. LNA modification of single-stranded DNA oligonucleotides allows subtle gene modification in mismatch-repair-proficient cells

    PubMed Central

    van Ravesteyn, Thomas W.; Dekker, Marleen; Fish, Alexander; Sixma, Titia K.; Wolters, Astrid; Dekker, Rob J.; te Riele, Hein P. J.

    2016-01-01

    Synthetic single-stranded DNA oligonucleotides (ssODNs) can be used to generate subtle genetic modifications in eukaryotic and prokaryotic cells without the requirement for prior generation of DNA double-stranded breaks. However, DNA mismatch repair (MMR) suppresses the efficiency of gene modification by >100-fold. Here we present a commercially available ssODN design that evades MMR and enables subtle gene modification in MMR-proficient cells. The presence of locked nucleic acids (LNAs) in the ssODNs at mismatching bases, or also at directly adjacent bases, allowed 1-, 2-, or 3-bp substitutions in MMR-proficient mouse embryonic stem cells as effectively as in MMR-deficient cells. Additionally, in MMR-proficient Escherichia coli, LNA modification of the ssODNs enabled effective single-base-pair substitution. In vitro, LNA modification of mismatches precluded binding of purified E. coli MMR protein MutS. These findings make ssODN-directed gene modification particularly well suited for applications that require the evaluation of a large number of sequence variants with an easy selectable phenotype. PMID:26951689

  10. Defective DNA single-strand break repair is responsible for senescence and neoplastic escape of epithelial cells

    PubMed Central

    Nassour, Joe; Martien, Sébastien; Martin, Nathalie; Deruy, Emeric; Tomellini, Elisa; Malaquin, Nicolas; Bouali, Fatima; Sabatier, Laure; Wernert, Nicolas; Pinte, Sébastien; Gilson, Eric; Pourtier, Albin; Pluquet, Olivier; Abbadie, Corinne

    2016-01-01

    The main characteristic of senescence is its stability which relies on the persistence of DNA damage. We show that unlike fibroblasts, senescent epithelial cells do not activate an ATM-or ATR-dependent DNA damage response (DDR), but accumulate oxidative-stress-induced DNA single-strand breaks (SSBs). These breaks remain unrepaired because of a decrease in PARP1 expression and activity. This leads to the formation of abnormally large and persistent XRCC1 foci that engage a signalling cascade involving the p38MAPK and leading to p16 upregulation and cell cycle arrest. Importantly, the default in SSB repair also leads to the emergence of post-senescent transformed and mutated precancerous cells. In human-aged skin, XRCC1 foci accumulate in the epidermal cells in correlation with a decline of PARP1, whereas DDR foci accumulate mainly in dermal fibroblasts. These findings point SSBs as a DNA damage encountered by epithelial cells with aging which could fuel the very first steps of carcinogenesis. PMID:26822533

  11. In Vitro Assessment of the Assisted Bidirectional Glenn Procedure for Stage One Single Ventricle Repair.

    PubMed

    Zhou, Jian; Esmaily-Moghadam, Mahdi; Conover, Timothy A; Hsia, Tain-Yen; Marsden, Alison L; Figliola, Richard S

    2015-09-01

    This in vitro study compares the hemodynamic performance of the Norwood and the Glenn circulations to assess the performance of a novel assisted bidirectional Glenn (ABG) procedure for stage one single ventricle surgery. In the ABG, the flow in a bidirectional Glenn procedure is assisted by injection of a high-energy flow stream from the systemic circulation using an aorta-caval shunt with nozzle. The aim is to explore experimentally the potential of the ABG as a surgical alternative to current surgical practice. The experiments are directly compared against previously published numerical simulations. A multiscale mock circulatory system was used to measure the hemodynamic performance of the three circulations. For each circulation, the system was tested using both low and high values of pulmonary vascular resistance. Resulting parameters measured were: pressure and flow rate at left/right pulmonary artery and superior vena cava (SVC). Systemic oxygen delivery (OD) was calculated. A parametric study of the ratio of ABG nozzle to shunt diameter was done. We report time-based comparisons with numerical simulations for the three surgical variants tested. The ABG circulation demonstrated an increase of 30-38% in pulmonary flow with a 2-3.7 mmHg increase in SVC pressure compared to the Glenn and a 4-14% higher systemic OD than either the Norwood or the Glenn. The nozzle/shunt diameter ratio affected the local hemodynamics. These experimental results agreed with those of the numerical model: mean flow values were not significantly different (p > 0.05) while mean pressures were comparable within 1.2 mmHg. The results verify the approaches providing two tools to study this complicated circulation. Using a realistic experimental model we demonstrate the performance of a novel surgical procedure with potential to improve patient hemodynamics in early palliation of the univentricular circulation. PMID:26577359

  12. DNA polymerases δ and λ cooperate in repairing double-strand breaks by microhomology-mediated end-joining in Saccharomyces cerevisiae.

    PubMed

    Meyer, Damon; Fu, Becky Xu Hua; Heyer, Wolf-Dietrich

    2015-12-15

    Maintenance of genome stability is carried out by a suite of DNA repair pathways that ensure the repair of damaged DNA and faithful replication of the genome. Of particular importance are the repair pathways, which respond to DNA double-strand breaks (DSBs), and how the efficiency of repair is influenced by sequence homology. In this study, we developed a genetic assay in diploid Saccharomyces cerevisiae cells to analyze DSBs requiring microhomologies for repair, known as microhomology-mediated end-joining (MMEJ). MMEJ repair efficiency increased concomitant with microhomology length and decreased upon introduction of mismatches. The central proteins in homologous recombination (HR), Rad52 and Rad51, suppressed MMEJ in this system, suggesting a competition between HR and MMEJ for the repair of a DSB. Importantly, we found that DNA polymerase delta (Pol δ) is critical for MMEJ, independent of microhomology length and base-pairing continuity. MMEJ recombinants showed evidence that Pol δ proofreading function is active during MMEJ-mediated DSB repair. Furthermore, mutations in Pol δ and DNA polymerase 4 (Pol λ), the DNA polymerase previously implicated in MMEJ, cause a synergistic decrease in MMEJ repair. Pol λ showed faster kinetics associating with MMEJ substrates following DSB induction than Pol δ. The association of Pol δ depended on RAD1, which encodes the flap endonuclease needed to cleave MMEJ intermediates before DNA synthesis. Moreover, Pol δ recruitment was diminished in cells lacking Pol λ. These data suggest cooperative involvement of both polymerases in MMEJ. PMID:26607450

  13. Conserved and nonconserved proteins for meiotic DNA breakage and repair in yeasts.

    PubMed Central

    Young, Jennifer A; Hyppa, Randy W; Smith, Gerald R

    2004-01-01

    During meiosis DNA double-strand breaks initiate recombination in the distantly related budding and fission yeasts and perhaps in most eukaryotes. Repair of broken meiotic DNA is essential for formation of viable gametes. We report here distinct but overlapping sets of proteins in these yeasts required for formation and repair of double-strand breaks. Meiotic DNA breakage in Schizosaccharomyces pombe did not require Rad50 or Rad32, although the homologs Rad50 and Mre11 are required in Saccharomyces cerevisiae; these proteins are required for meiotic DNA break repair in both yeasts. DNA breakage required the S. pombe midmeiosis transcription factor Mei4, but the structurally unrelated midmeiosis transcription factor Ndt80 is not required for breakage in S. cerevisiae. Rhp51, Swi5, and Rad22 + Rti1 were required for full levels of DNA repair in S. pombe, as are the related S. cerevisiae proteins Rad51, Sae3, and Rad52. Dmc1 was not required for repair in S. pombe, but its homolog Dmc1 is required in the well-studied strain SK1 of S. cerevisiae. Additional proteins required in one yeast have no obvious homologs in the other yeast. The occurrence of conserved and nonconserved proteins indicates potential diversity in the mechanism of meiotic recombination and divergence of the machinery during the evolution of eukaryotes. PMID:15238514

  14. Single-cell microarray enables high-throughput evaluation of DNA double-strand breaks and DNA repair inhibitors

    PubMed Central

    Weingeist, David M.; Ge, Jing; Wood, David K.; Mutamba, James T.; Huang, Qiuying; Rowland, Elizabeth A.; Yaffe, Michael B.; Floyd, Scott; Engelward, Bevin P.

    2013-01-01

    A key modality of non-surgical cancer management is DNA damaging therapy that causes DNA double-strand breaks that are preferentially toxic to rapidly dividing cancer cells. Double-strand break repair capacity is recognized as an important mechanism in drug resistance and is therefore a potential target for adjuvant chemotherapy. Additionally, spontaneous and environmentally induced DSBs are known to promote cancer, making DSB evaluation important as a tool in epidemiology, clinical evaluation and in the development of novel pharmaceuticals. Currently available assays to detect double-strand breaks are limited in throughput and specificity and offer minimal information concerning the kinetics of repair. Here, we present the CometChip, a 96-well platform that enables assessment of double-strand break levels and repair capacity of multiple cell types and conditions in parallel and integrates with standard high-throughput screening and analysis technologies. We demonstrate the ability to detect multiple genetic deficiencies in double-strand break repair and evaluate a set of clinically relevant chemical inhibitors of one of the major double-strand break repair pathways, non-homologous end-joining. While other high-throughput repair assays measure residual damage or indirect markers of damage, the CometChip detects physical double-strand breaks, providing direct measurement of damage induction and repair capacity, which may be useful in developing and implementing treatment strategies with reduced side effects. PMID:23422001

  15. Replication Protein A: Single-stranded DNA's first responder : Dynamic DNA-interactions allow Replication Protein A to direct single-strand DNA intermediates into different pathways for synthesis or repair

    PubMed Central

    Chen, Ran; Wold, Marc S.

    2015-01-01

    Summary Replication Protein A (RPA), the major single-stranded DNA-binding protein in eukaryotic cells, is required for processing of single-stranded DNA (ssDNA) intermediates found in replication, repair and recombination. Recent studies have shown that RPA binding to ssDNA is highly dynamic and that more than high-affinity binding is needed for function. Analysis of DNA binding mutants identified forms of RPA with reduced affinity for ssDNA that are fully active, and other mutants with higher affinity that are inactive. Single molecule studies showed that while RPA binds ssDNA with high affinity, the RPA complex can rapidly diffuse along ssDNA and be displaced by other proteins that act on ssDNA. Finally, dynamic DNA binding allows RPA to prevent error-prone repair of double-stranded breaks and promote error-free repair. Together, these findings suggest a new paradigm where RPA acts as a first responder at sites with ssDNA, thereby actively coordinating DNA repair and DNA synthesis. PMID:25171654

  16. Single Nucleotide Polymorphisms in Nucleotide Excision Repair Genes, Cigarette Smoking, and the Risk of Head and Neck Cancer

    PubMed Central

    Wyss, Annah B.; Herring, Amy H.; Avery, Christy L.; Weissler, Mark C.; Bensen, Jeannette T.; Barnholtz-Sloan, Jill S.; Funkhouser, William K.; Olshan, Andrew F.

    2013-01-01

    Background Cigarette smoking is associated with increased head and neck cancer (HNC) risk. Tobacco-related carcinogens are known to cause bulky DNA adducts. Nucleotide excision repair (NER) genes encode enzymes that remove adducts and may be independently associated with HNC, as well as modifiers of the association between smoking and HNC. Methods Using population-based case-control data from the Carolina Head and Neck Cancer Epidemiology Study (1,227 cases, 1,325 controls), race-stratified (white, African American) conventional and hierarchical logistic regression models were utilized to estimate odds ratios (OR) with 95% intervals (I) for the independent and joint effects of cigarette smoking and 84 single nucleotide polymorphisms (SNPs) from 15 NER genes on HNC risk. Results The odds of HNC were elevated among ever cigarette smokers, and increased with smoking duration and frequency. Among whites, rs4150403 on ERCC3 was associated with increased HNC odds (AA+AG vs. GG, OR=1.28, 95% I=1.01,1.61). Among African Americans, rs4253132 on ERCC6 was associated with decreased HNC odds (CC+CT vs. TT, OR=0.62, 95% I=0.45,0.86). Interactions between ever cigarette smoking and three SNPs (rs4253132 on ERCC6, rs2291120 on DDB2, and rs744154 on ERCC4) suggested possible departures from additivity among whites. Conclusions We did not find associations between some previously studied NER variants and HNC. We did identify new associations between two SNPs and HNC and three suggestive cigarette-SNP interactions to consider in future studies. Impact We conducted one of the most comprehensive evaluations of NER variants, identifying a few SNPs from biologically plausible candidate genes associated with HNC and possibly interacting with cigarette smoking. PMID:23720401

  17. Single Stage Repair for Aortic Coarctation associated with Intracardiac Defects Using Extra-Anatomic Bypass Graft in Adults

    PubMed Central

    Ates, Mehmet Sanser; Onuk, Burak Emre; Bakkaloglu, Beyhan; Sungur, Umit Pinar; Kurtoglu, Murat; Karagoz, Yahya Halidun

    2016-01-01

    Background and Objectives Coarctation of the aorta in adulthood is generally associated with other cardiovascular disorders requiring surgical management. An extra anatomic bypass grafting from the ascending to descending aorta by posterior pericardial approach via median sternotomy could be a reasonable single stage surgical strategy for these patients. Subjects and Methods Seven male patients aged between 14-41 years underwent an extra anatomic bypass grafting for coarctation repair concomitantly with the surgical management of the associated cardiovascular disorders via median sternotomy. Preoperative mean systolic arterial blood pressure was 161.8±24.5 mmHg, although the patients were under treatment of different combinations of antihypertensive agents. Additional surgical procedures were: aortic valve replacement (n=4), ventricular septal defect (VSD) closure (n=2), ascending aortic replacement (n=3) and Bentall procedure (n=1). None of our patients have been previously diagnosed or operated on for coarctation. Data were evaluated during their hospital stay and in post-operative follow-up. Results The post-operative course was uneventful in all but one patient was re-operated on due to bleeding. There was neither mortality nor significant morbidity during the in-hospital period and all patients were discharged within 5-9 (mean: 6.3±1.5) days. The mean follow up period was 71.83±23 months (range: 23-95 months). Unfortunately one of our patients could not be contacted for a follow up period because of invalid personal data. Conclusion Coarctation of the aorta in adulthood associated with other cardiovascular disorders can be operated on simultaneously via an extra anatomic bypass grafting technique with low morbidity and mortality. PMID:27482266

  18. Failed distal biceps tendon repair using a single-incision EndoButton technique and its successful treatment: case report.

    PubMed

    Desai, Shaunak S; Larkin, Brian J; Najibi, Soheil

    2010-12-01

    Surgical repair has become a mainstay in the treatment of ruptures of the distal biceps tendon and multiple surgical techniques have been described advocating anatomic or near-anatomic repair. Fixation with an EndoButton technique has been shown to have superior fixation strength and durable clinical outcomes. Here, we describe a case of failed EndoButton fixation of the distal biceps tendon, and its successful treatment. PMID:21115300

  19. Single-Stage Repair of an Unusual Association: Congenital Gerbode Defect, Hypoplastic Aortic Arch, and Partially Anomalous Pulmonary Venous Return in an Infant.

    PubMed

    Flores, Saul; Kimball, Thomas R; Nelson, David P; Morales, David L S

    2016-07-01

    We present the case of a two-month-old male with congenital Gerbode defect, hypoplastic aortic arch, and left-sided partially anomalous pulmonary venous return. The patient underwent single-stage surgical repair, which consisted of aortic arch advancement with resection of the coarctation segment, pulmonary vein repair, and primary closure of the Gerbode defect. The anomalous pulmonary vein posed a particular challenge due to its size and distance from the left atrium, which we approached with a posterior atrial wall trapdoor baffle technique, without mobilizing the affected vein. Postoperatively and at one year follow-up, there was no evidence of residual lesions and there was unobstructed flow pattern across the aortic arch and the affected pulmonary vein.

  20. Mutations in two Ku homologs define a DNA end-joining repair pathway in Saccharomyces cerevisiae.

    PubMed Central

    Milne, G T; Jin, S; Shannon, K B; Weaver, D T

    1996-01-01

    DNA double-strand break (DSB) repair in mammalian cells is dependent on the Ku DNA binding protein complex. However, the mechanism of Ku-mediated repair is not understood. We discovered a Saccharomyces cerevisiae gene (KU80) that is structurally similar to the 80-kDa mammalian Ku subunit. Ku8O associates with the product of the HDF1 gene, forming the major DNA end-binding complex of yeast cells. DNA end binding was absent in ku80delta, hdf1delta, or ku80delta hdf1delta strains. Antisera specific for epitope tags on Ku80 and Hdf1 were used in supershift and immunodepletion experiments to show that both proteins are directly involved in DNA end binding. In vivo, the efficiency of two DNA end-joining processes were reduced >10-fold in ku8Odelta, hdfldelta, or ku80delta hdf1delta strains: repair of linear plasmid DNA and repair of an HO endonuclease-induced chromosomal DSB. These DNA-joining defects correlated with DNA damage sensitivity, because ku80delta and hdf1delta strains were also sensitive to methylmethane sulfonate (MMS). Ku-dependent repair is distinct from homologous recombination, because deletion of KU80 and HDF1 increased the MMS sensitivity of rad52delta. Interestingly, rad5Odelta, also shown here to be defective in end joining, was epistatic with Ku mutations for MMS repair and end joining. Therefore, Ku and Rad50 participate in an end-joining pathway that is distinct from homologous recombinational repair. Yeast DNA end joining is functionally analogous to DSB repair and V(D)J recombination in mammalian cells. PMID:8754818

  1. Single-stage surgical repair in a complex case of aberrant right subclavian artery aneurysm and common carotid trunk

    PubMed Central

    2013-01-01

    Aberrant right subclavian artery with coexisting common carotid trunk is an extremely rare congenital anomaly affecting <0.1% of the population. We report the case of a 77-year-old Caucasian man presenting with dysphagia and dyspnea secondary to an aberrant right subclavian artery aneurysm and describe our technique for open surgical repair. PMID:23618166

  2. Human single-stranded DNA binding protein 1 (hSSB1/NABP2) is required for the stability and repair of stalled replication forks.

    PubMed

    Bolderson, Emma; Petermann, Eva; Croft, Laura; Suraweera, Amila; Pandita, Raj K; Pandita, Tej K; Helleday, Thomas; Khanna, Kum Kum; Richard, Derek J

    2014-06-01

    Aberrant DNA replication is a primary cause of mutations that are associated with pathological disorders including cancer. During DNA metabolism, the primary causes of replication fork stalling include secondary DNA structures, highly transcribed regions and damaged DNA. The restart of stalled replication forks is critical for the timely progression of the cell cycle and ultimately for the maintenance of genomic stability. Our previous work has implicated the single-stranded DNA binding protein, hSSB1/NABP2, in the repair of DNA double-strand breaks via homologous recombination. Here, we demonstrate that hSSB1 relocates to hydroxyurea (HU)-damaged replication forks where it is required for ATR and Chk1 activation and recruitment of Mre11 and Rad51. Consequently, hSSB1-depleted cells fail to repair and restart stalled replication forks. hSSB1 deficiency causes accumulation of DNA strand breaks and results in chromosome aberrations observed in mitosis, ultimately resulting in hSSB1 being required for survival to HU and camptothecin. Overall, our findings demonstrate the importance of hSSB1 in maintaining and repairing DNA replication forks and for overall genomic stability.

  3. Single-nucleotide polymorphisms in base excision repair, nucleotide excision repair, and double strand break genes as markers for response to radiotherapy in patients with Stage I to II head-and-neck cancer

    SciTech Connect

    Carles, Joan . E-mail: jcarles@imas.imim.es; Monzo, Mariano; Amat, Marta; Jansa, Sonia; Artells, Rosa; Navarro, Alfons; Foro, Palmira; Alameda, Francesc; Gayete, Angel; Gel, Bernat; Miguel, Maribel; Albanell, Joan; Fabregat, Xavier

    2006-11-15

    Purpose: Polymorphisms in DNA repair genes can influence response to radiotherapy. We analyzed single-nucleotide polymorphisms (SNP) in nine DNA repair genes in 108 patients with head-and-neck cancer (HNSCC) who had received radiotherapy only. Methods and Materials: From May 1993 to December 2004, patients with Stage I and II histopathologically confirmed HNSCC underwent radiotherapy. DNA was obtained from paraffin-embedded tissue, and SNP analysis was performed using a real-time polymerase chain reaction allelic discrimination TaqMan assay with minor modifications. Results: Patients were 101 men (93.5%) and 7 (6.5%) women, with a median age of 64 years (range, 40 to 89 years). Of the patients, 76 (70.4%) patients were Stage I and 32 (29.6%) were Stage II. The XPF/ERCC1 SNP at codon 259 and XPG/ERCC5 at codon 46 emerged as significant predictors of progression (p 0.00005 and 0.049, respectively) and survival (p = 0.0089 and 0.0066, respectively). Similarly, when variant alleles of XPF/ERCC1, XPG/ERCC5 and XPA were examined in combination, a greater number of variant alleles was associated with shorter time to progression (p = 0.0003) and survival (p 0.0002). Conclusions: Genetic polymorphisms in XPF/ERCC1, XPG/ERCC5, and XPA may significantly influence response to radiotherapy; large studies are warranted to confirm their role in HNSCC.

  4. Single-Stage Repair of Thoracic Aortic Aneurysm through a Median Sternotomy in a Patient with Pseudocoarctation of the Aorta and Severe Aortic Valve Stenosis

    PubMed Central

    Morimoto, Hironobu; Mukai, Shogo

    2015-01-01

    Pseudocoarctation of the aorta is a rare anomaly and considered a benign condition. Pseudocoarctation of the aorta has been associated with aneurysm formation in the thoracic aorta, which may cause sudden rupture or dissection. Thus, the presence of an aneurysm in combination with pseudocoarctation of the aorta is thought to be an indication for surgery. We present a case of pseudocoarctation of the aorta associated with thoracic aortic aneurysm and severe aortic valve stenosis with a bicuspid aortic valve. In our case, single-stage repair was performed through a median sternotomy using our “pleural-window approach.” PMID:26131037

  5. Telomere Dysfunction Triggers Palindrome Formation Independently of Double-Strand Break Repair Mechanisms

    PubMed Central

    Raykov, Vasil; Marvin, Marcus E.; Louis, Edward J.; Maringele, Laura

    2016-01-01

    Inverted chromosome duplications or palindromes are linked with genetic disorders and malignant transformation. They are considered by-products of DNA double-strand break (DSB) repair: the homologous recombination (HR) and the nonhomologous end joining (NHEJ). Palindromes near chromosome ends are often triggered by telomere losses. An important question is to what extent their formation depends upon DSB repair mechanisms. Here we addressed this question using yeast genetics and comparative genomic hybridization. We induced palindrome formation by passaging cells lacking any form of telomere maintenance (telomerase and telomere recombination). Surprisingly, we found that DNA ligase 4, essential for NHEJ, did not make a significant contribution to palindrome formation induced by telomere losses. Moreover RAD51, important for certain HR-derived mechanisms, had little effect. Furthermore RAD52, which is essential for HR in yeast, appeared to decrease the number of palindromes in cells proliferating without telomeres. This study also uncovered an important role for Rev3 and Rev7 (but not for Pol32) subunits of polymerase ζ in the survival of cells undergoing telomere losses and forming palindromes. We propose a model called short-inverted repeat-induced synthesis in which DNA synthesis, rather than DSB repair, drives the inverted duplication triggered by telomere dysfunction. PMID:27334270

  6. Repair of endonuclease-induced double-strand breaks in Saccharomyces cerevisiae: essential role for genes associated with nonhomologous end-joining.

    PubMed Central

    Lewis, L K; Westmoreland, J W; Resnick, M A

    1999-01-01

    Repair of double-strand breaks (DSBs) in chromosomal DNA by nonhomologous end-joining (NHEJ) is not well characterized in the yeast Saccharomyces cerevisiae. Here we demonstrate that several genes associated with NHEJ perform essential functions in the repair of endonuclease-induced DSBs in vivo. Galactose-induced expression of EcoRI endonuclease in rad50, mre11, or xrs2 mutants, which are deficient in plasmid DSB end-joining and some forms of recombination, resulted in G2 arrest and rapid cell killing. Endonuclease synthesis also produced moderate cell killing in sir4 strains. In contrast, EcoRI caused prolonged cell-cycle arrest of recombination-defective rad51, rad52, rad54, rad55, and rad57 mutants, but cells remained viable. Cell-cycle progression was inhibited in excision repair-defective rad1 mutants, but not in rad2 cells, indicating a role for Rad1 processing of the DSB ends. Phenotypic responses of additional mutants, including exo1, srs2, rad5, and rdh54 strains, suggest roles in recombinational repair, but not in NHEJ. Interestingly, the rapid cell killing in haploid rad50 and mre11 strains was largely eliminated in diploids, suggesting that the cohesive-ended DSBs could be efficiently repaired by homologous recombination throughout the cell cycle in the diploid mutants. These results demonstrate essential but separable roles for NHEJ pathway genes in the repair of chromosomal DSBs that are structurally similar to those occurring during cellular development. PMID:10430580

  7. Base-Excision-Repair-Induced Construction of a Single Quantum-Dot-Based Sensor for Sensitive Detection of DNA Glycosylase Activity.

    PubMed

    Wang, Li-Juan; Ma, Fei; Tang, Bo; Zhang, Chun-Yang

    2016-08-01

    DNA glycosylase is an initiating enzyme of cellular base excision repair pathway which is responsible for the repair of various DNA lesions and the maintenance of genomic stability, and the dysregulation of DNA glycosylase activity is associated with a variety of human pathology. Accurate detection of DNA glycosylase activity is critical to both clinical diagnosis and therapeutics, but conventional methods for the DNA glycosylase assay are usually time-consuming with poor sensitivity. Here, we demonstrate the base-excision-repair-induced construction of a single quantum dot (QD)-based sensor for highly sensitive measurement of DNA glycosylase activity. We use human 8-oxoguanine-DNA glycosylase 1 (hOGG1), which is responsible for specifically repairing the damaged 8-hydroxyguanine (8-oxoG, one of the most abundant and widely studied DNA damage products), as a model DNA glycosylase. In the presence of biotin-labeled DNA substrate, the hOGG1 may catalyze the removal of 8-oxo G from 8-oxoG·C base pairs to generate an apurinic/apyrimidinic (AP) site. With the assistance of apurinic/apyrimidinic endonuclease (APE1), the cleavage of the AP site results in the generation of a single-nucleotide gap. Subsequently, DNA polymerase β incorporates a Cy5-labeled dGTP into the DNA substrate to fill the gap. With the addition of streptavidin-coated QDs, a QD-DNA-Cy5 nanostructure is formed via specific biotin-streptavidin binding, inducing the occurrence of fluorescence resonance energy transfer (FRET) from the QD to Cy5. The resulting Cy5 signal can be simply monitored by total internal reflection fluorescence (TIRF) imaging. The proposed method enables highly sensitive measurement of hOGG1 activity with a detection limit of 1.8 × 10(-6) U/μL. Moreover, it can be used to measure the enzyme kinetic parameters and detect the hOGG1 activity in crude cell extracts, offering a powerful tool for biomedical research and clinical diagnosis. PMID:27401302

  8. Assessment of oxidative DNA damage and repair at single cellular level via real-time monitoring of 8-OHdG biomarker.

    PubMed

    Prabhulkar, Shradha; Li, Chen-Zhong

    2010-12-15

    8-Hydroxydeoxyguanosine (8-OHdG) is the most important and best-documented biomarker of oxidative stress, which is involved in the instigation of various diseases. 8-OHdG levels correlate to oxidative DNA damage which is known to be the root cause of a variety of age-related chronic diseases. The purpose of our research was to develop a detection strategy capable of measuring 8-OHdG in real-time at the surface of a single cell. Activated carbon fiber microelectrodes were used as the sensing platform. The microelectrodes were used to measure 8-OHdG release from single lung epithelial cells under the influence of nicotine. In order to evaluate the direct role of nicotine in tobacco induced genotoxicity, we studied the influence of parameters such as nicotine concentration and exposure times on 8-OHdG secretion. 2-8 mM nicotine solutions induced dose-dependent DNA damage in single cells, which was observed via amperometric measurements of secreted 8-OHdG biomarker. Real-time 8-OHdG measurements from single cells exposed to 4 mM nicotine solution revealed cessation of 8-OHdG secretion after 110 min. We have successfully outlined a methodology to detect 8-OHdG at the surface of single cells. A similar protocol can be used to evaluate oxidative DNA damage and repair mechanisms in other disease models. PMID:20863679

  9. Clubfoot repair

    MedlinePlus

    ... release; Talipes equinovarus - repair; Tibialis anterior tendon transfer Images Clubfoot repair - series References Kelly DM. Congenital Anomalies ... provided herein should not be used during any medical emergency or for the diagnosis or treatment of ...

  10. Tendon repair

    MedlinePlus

    Repair of tendon ... Tendon repair can be performed using: Local anesthesia (the immediate area of the surgery is pain-free) ... a cut on the skin over the injured tendon. The damaged or torn ends of the tendon ...

  11. Laparoscopic bridging vs. anatomic open reconstruction for midline abdominal hernia mesh repair [LABOR]: single-blinded, multicenter, randomized, controlled trial on long-term functional results

    PubMed Central

    2013-01-01

    Background Re-approximation of the rectal muscles along the midline is recommended by some groups as a rule for incisional and ventral hernia repairs. The introduction of laparoscopic repair has generated a debate because it is not aimed at restoring abdominal wall integrity but instead aims just to bridge the defect. Whether restoration of the abdominal integrity has a real impact on patient mobility is questionable, and the available literature provides no definitive answer. The present study aims to compare the functional results of laparoscopic bridging with those of re-approximation of the rectal muscle in the midline as a mesh repair for ventral and incisional abdominal defect through an “open” access. We hypothesized that, for the type of defect suitable for a laparoscopic bridging, the effect of an anatomical reconstruction is near negligible, thus not a fixed rule. Methods and design The LABOR trial is a multicenter, prospective, two-arm, single-blinded, randomized trial. Patients of more than 60 years of age with a defect of less than 10 cm at its greatest diameter will be randomly submitted to open Rives or laparoscopic defect repair. All the participating patients will have a preoperative evaluation of their abdominal wall strength and mobility along with volumetry, respiratory function test, intraabdominal pressure and quality of life assessment. The primary outcome will be the difference in abdominal wall strength as measured by a double leg-lowering test performed at 12 months postoperatively. The secondary outcomes will be the rate of recurrence and changes in baseline abdominal mobility, respiratory function tests, intraabdominal pressure, CT volumetry and quality of life at 6 and 12 months postoperatively. Discussion The study will help to define the most suitable treatment for small-medium incisional and primary hernias in patients older than 60 years. Given a similar mid-term recurrence rate in both groups, if the trial shows no differences

  12. Effects of double-strand break repair proteins on vertebrate telomere structure

    PubMed Central

    Wei, Chao; Skopp, Rose; Takata, Minoru; Takeda, Shunichi; Price, Carolyn M.

    2002-01-01

    Although telomeres are not recognized as double-strand breaks (DSBs), some DSB repair proteins are present at telomeres and are required for telomere maintenance. To learn more about the telomeric function of proteins from the homologous recombination (HR) and non-homologous end joining pathways (NHEJ), we have screened a panel of chicken DT40 knockout cell lines for changes in telomere structure. In contrast to what has been observed in Ku-deficient mice, we found that Ku70 disruption did not result in telomere–telomere fusions and had no effect on telomere length or the structure of the telomeric G-strand overhang. G-overhang length was increased by Rad51 disruption but unchanged by disruption of DNA-PKcs, Mre11, Rad52, Rad54, XRCC2 or XRCC3. The effect of Rad51 depletion was unexpected because gross alterations in telomere structure have not been detected in yeast HR mutants. Thus, our results indicate that Rad51 has a previously undiscovered function at vertebrate telomeres. They also indicate that Mre11 is not required to generate G-overhangs. Although Mre11 has been implicated in overhang generation, overhang structure had not previously been examined in Mre11-deficient cells. Overall our findings indicate that there are significant species-specific differences in the telomeric function of DSB repair proteins. PMID:12087170

  13. Genome-wide analysis of human global and transcription-coupled excision repair of UV damage at single-nucleotide resolution.

    PubMed

    Hu, Jinchuan; Adar, Sheera; Selby, Christopher P; Lieb, Jason D; Sancar, Aziz

    2015-05-01

    We developed a method for genome-wide mapping of DNA excision repair named XR-seq (excision repair sequencing). Human nucleotide excision repair generates two incisions surrounding the site of damage, creating an ∼30-mer. In XR-seq, this fragment is isolated and subjected to high-throughput sequencing. We used XR-seq to produce stranded, nucleotide-resolution maps of repair of two UV-induced DNA damages in human cells: cyclobutane pyrimidine dimers (CPDs) and (6-4) pyrimidine-pyrimidone photoproducts [(6-4)PPs]. In wild-type cells, CPD repair was highly associated with transcription, specifically with the template strand. Experiments in cells defective in either transcription-coupled excision repair or general excision repair isolated the contribution of each pathway to the overall repair pattern and showed that transcription-coupled repair of both photoproducts occurs exclusively on the template strand. XR-seq maps capture transcription-coupled repair at sites of divergent gene promoters and bidirectional enhancer RNA (eRNA) production at enhancers. XR-seq data also uncovered the repair characteristics and novel sequence preferences of CPDs and (6-4)PPs. XR-seq and the resulting repair maps will facilitate studies of the effects of genomic location, chromatin context, transcription, and replication on DNA repair in human cells.

  14. Recombinational DNA repair: the RecF and RecR proteins limit the extension of RecA filaments beyond single-strand DNA gaps.

    PubMed

    Webb, B L; Cox, M M; Inman, R B

    1997-10-31

    In the presence of both the RecF and RecR proteins, RecA filament extension from a single strand gap into adjoining duplex DNA is attenuated. RecR protein alone has no effect, and RecF protein alone has a reduced activity. The RecFR complexes bind randomly, primarily to the duplex regions of the DNA, and the extension of the RecA filament is halted at the first complex encountered. A very slow lengthening of RecA filaments observed in the presence of RecFR is virtually eliminated when RecF is replaced with an RecF mutant protein that does not hydrolyze ATP. These observations are incorporated into an expanded model for the functions of RecF, RecO, and RecR proteins in the early stages of postreplication DNA repair. PMID:9363943

  15. Homologous recombination and non-homologous end-joining repair pathways in bovine embryos with different developmental competence

    SciTech Connect

    Henrique Barreta, Marcos; Garziera Gasperin, Bernardo; Braga Rissi, Vitor; Cesaro, Matheus Pedrotti de; Ferreira, Rogerio; Oliveira, Joao Francisco de; Goncalves, Paulo Bayard Dias; Bordignon, Vilceu

    2012-10-01

    This study investigated the expression of genes controlling homologous recombination (HR), and non-homologous end-joining (NHEJ) DNA-repair pathways in bovine embryos of different developmental potential. It also evaluated whether bovine embryos can respond to DNA double-strand breaks (DSBs) induced with ultraviolet irradiation by regulating expression of genes involved in HR and NHEJ repair pathways. Embryos with high, intermediate or low developmental competence were selected based on the cleavage time after in vitro insemination and were removed from in vitro culture before (36 h), during (72 h) and after (96 h) the expected period of embryonic genome activation. All studied genes were expressed before, during and after the genome activation period regardless the developmental competence of the embryos. Higher mRNA expression of 53BP1 and RAD52 was found before genome activation in embryos with low developmental competence. Expression of 53BP1, RAD51 and KU70 was downregulated at 72 h and upregulated at 168 h post-insemination in response to DSBs induced by ultraviolet irradiation. In conclusion, important genes controlling HR and NHEJ DNA-repair pathways are expressed in bovine embryos, however genes participating in these pathways are only regulated after the period of embryo genome activation in response to ultraviolet-induced DSBs.

  16. Role of Human DNA Glycosylase Nei-like 2 (NEIL2) and Single Strand Break Repair Protein Polynucleotide Kinase 3′-Phosphatase in Maintenance of Mitochondrial Genome*

    PubMed Central

    Mandal, Santi M.; Hegde, Muralidhar L.; Chatterjee, Arpita; Hegde, Pavana M.; Szczesny, Bartosz; Banerjee, Dibyendu; Boldogh, Istvan; Gao, Rui; Falkenberg, Maria; Gustafsson, Claes M.; Sarkar, Partha S.; Hazra, Tapas K.

    2012-01-01

    The repair of reactive oxygen species-induced base lesions and single strand breaks (SSBs) in the nuclear genome via the base excision (BER) and SSB repair (SSBR) pathways, respectively, is well characterize, and important for maintaining genomic integrity. However, the role of mitochondrial (mt) BER and SSBR proteins in mt genome maintenance is not completely clear. Here we show the presence of the oxidized base-specific DNA glycosylase Nei-like 2 (NEIL2) and the DNA end-processing enzyme polynucleotide kinase 3′-phosphatase (PNKP) in purified human mitochondrial extracts (MEs). Confocal microscopy revealed co-localization of PNKP and NEIL2 with the mitochondrion-specific protein cytochrome c oxidase subunit 2 (MT-CO2). Further, chromatin immunoprecipitation analysis showed association of NEIL2 and PNKP with the mitochondrial genes MT-CO2 and MT-CO3 (cytochrome c oxidase subunit 3); importantly, both enzymes also associated with the mitochondrion-specific DNA polymerase γ. In cell association of NEIL2 and PNKP with polymerase γ was further confirmed by proximity ligation assays. PNKP-depleted ME showed a significant decrease in both BER and SSBR activities, and PNKP was found to be the major 3′-phosphatase in human ME. Furthermore, individual depletion of NEIL2 and PNKP in human HEK293 cells caused increased levels of oxidized bases and SSBs in the mt genome, respectively. Taken together, these studies demonstrate the critical role of NEIL2 and PNKP in maintenance of the mammalian mitochondrial genome. PMID:22130663

  17. The DNA repair inhibitors hydroxyurea and cytosine arabinoside enhance the sensitivity of the alkaline single-cell gel electrophoresis ('comet') assay in metabolically-competent MCL-5 cells.

    PubMed

    Martin, F L; Cole, K J; Orme, M H; Grover, P L; Phillips, D H; Venitt, S

    1999-09-15

    We have found previously that the metabolically-competent human MCL-5 cell line did not appear to be usefully sensitive to the DNA-damaging effects of several carcinogens, as measured by the alkaline single-cell gel electrophoresis ('comet') assay. We therefore sought to increase its sensitivity by inhibiting DNA repair during exposure to test compounds, using 10 mM hydroxyurea (HU) and 1.8 mM cytosine arabinoside (ara-C), which inhibit DNA resynthesis during nucleotide excision repair. The following compounds were tested, using a 30-min exposure, in the absence or presence of HU/ara-C: 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (8-MeIQx), 2-amino-3,4,8-trimethylimidazo[4,5-f]quinoxaline (4, 8-DiMeIQx), 2-amino-3-methylimidazo[4,5-f]quinoline (IQ), 2-amino-9H-pyrido[2,3-b]indole (A[alpha]C), 2-amino-3-methyl-9H-pyrido[2,3-b]indole (MeA[alpha]C), 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), benzo[a]pyrene (B[a]P), 3-methylcholanthrene (3-MCA), 7, 12-dimethylbenz[a]anthracene (DMBA), 1-nitropyrene (1-NP), 2-nitrofluorene (2-NF), aniline, o-toluidine, benzene, lindane, bleomycin, cisplatin, N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), sodium chromate, chromic chloride, and diethylstilboestrol (DES). We made the following observations. The background level of comet formation was reasonably constant over several months and was increased only slightly, but significantly, in the presence of the DNA-repair inhibitors. All compounds that induced comet formation did so without appreciable cytotoxicity as assessed by trypan blue exclusion. Of the compounds tested, the heterocyclic amines and polycyclic aromatic hydrocarbons (with the exceptions of PhIP and B[a]P) failed to induce convincing levels of comet formation in the absence of repair inhibitors. In their presence the heterocyclic amines tested induced comet formation (with the exception of 8-MeIQx), with widely differing potencies. 1-NP failed to elicit marked comet formation even in the presence of HU

  18. Craniosynostosis repair

    MedlinePlus

    ... will be asleep and will not feel pain. Traditional surgery is called open repair. It includes these ... helps keep the swelling down. Talking, singing, playing music, and telling stories may help soothe your child. ...

  19. Carboxyl-modified single-wall carbon nanotubes improve bone tissue formation in vitro and repair in an in vivo rat model.

    PubMed

    Barrientos-Durán, Antonio; Carpenter, Ellen M; Zur Nieden, Nicole I; Malinin, Theodore I; Rodríguez-Manzaneque, Juan Carlos; Zanello, Laura P

    2014-01-01

    The clinical management of bone defects caused by trauma or nonunion fractures remains a challenge in orthopedic practice due to the poor integration and biocompatibility properties of the scaffold or implant material. In the current work, the osteogenic properties of carboxyl-modified single-walled carbon nanotubes (COOH-SWCNTs) were investigated in vivo and in vitro. When human preosteoblasts and murine embryonic stem cells were cultured on coverslips sprayed with COOH-SWCNTs, accelerated osteogenic differentiation was manifested by increased expression of classical bone marker genes and an increase in the secretion of osteocalcin, in addition to prior mineralization of the extracellular matrix. These results predicated COOH-SWCNTs' use to further promote osteogenic differentiation in vivo. In contrast, both cell lines had difficulties adhering to multi-walled carbon nanotube-based scaffolds, as shown by scanning electron microscopy. While a suspension of SWCNTs caused cytotoxicity in both cell lines at levels >20 μg/mL, these levels were never achieved by release from sprayed SWCNTs, warranting the approach taken. In vivo, human allografts formed by the combination of demineralized bone matrix or cartilage particles with SWCNTs were implanted into nude rats, and ectopic bone formation was analyzed. Histological analysis of both types of implants showed high permeability and pore connectivity of the carbon nanotube-soaked implants. Numerous vascularization channels appeared in the formed tissue, additional progenitor cells were recruited, and areas of de novo ossification were found 4 weeks post-implantation. Induction of the expression of bone-related genes and the presence of secreted osteopontin protein were also confirmed by quantitative polymerase chain reaction analysis and immunofluorescence, respectively. In summary, these results are in line with prior contributions that highlight the suitability of SWCNTs as scaffolds with high bone

  20. Carboxyl-modified single-wall carbon nanotubes improve bone tissue formation in vitro and repair in an in vivo rat model

    PubMed Central

    Barrientos-Durán, Antonio; Carpenter, Ellen M; zur Nieden, Nicole I; Malinin, Theodore I; Rodríguez-Manzaneque, Juan Carlos; Zanello, Laura P

    2014-01-01

    The clinical management of bone defects caused by trauma or nonunion fractures remains a challenge in orthopedic practice due to the poor integration and biocompatibility properties of the scaffold or implant material. In the current work, the osteogenic properties of carboxyl-modified single-walled carbon nanotubes (COOH–SWCNTs) were investigated in vivo and in vitro. When human preosteoblasts and murine embryonic stem cells were cultured on coverslips sprayed with COOH–SWCNTs, accelerated osteogenic differentiation was manifested by increased expression of classical bone marker genes and an increase in the secretion of osteocalcin, in addition to prior mineralization of the extracellular matrix. These results predicated COOH–SWCNTs’ use to further promote osteogenic differentiation in vivo. In contrast, both cell lines had difficulties adhering to multi-walled carbon nanotube-based scaffolds, as shown by scanning electron microscopy. While a suspension of SWCNTs caused cytotoxicity in both cell lines at levels >20 μg/mL, these levels were never achieved by release from sprayed SWCNTs, warranting the approach taken. In vivo, human allografts formed by the combination of demineralized bone matrix or cartilage particles with SWCNTs were implanted into nude rats, and ectopic bone formation was analyzed. Histological analysis of both types of implants showed high permeability and pore connectivity of the carbon nanotube-soaked implants. Numerous vascularization channels appeared in the formed tissue, additional progenitor cells were recruited, and areas of de novo ossification were found 4 weeks post-implantation. Induction of the expression of bone-related genes and the presence of secreted osteopontin protein were also confirmed by quantitative polymerase chain reaction analysis and immunofluorescence, respectively. In summary, these results are in line with prior contributions that highlight the suitability of SWCNTs as scaffolds with high bone

  1. Pectus excavatum repair

    MedlinePlus

    Funnel chest repair; Chest deformity repair; Sunken chest repair; Cobbler's chest repair; Nuss repair; Ravitch repair ... There are two types of surgery to repair this condition -- open surgery ... surgery is done while the child is in a deep sleep and pain- ...

  2. Combining Freshly Isolated Chondroprogenitor Cells from the Infrapatellar Fat Pad with a Growth Factor Delivery Hydrogel as a Putative Single Stage Therapy for Articular Cartilage Repair

    PubMed Central

    Ahearne, Mark; Liu, Yurong

    2014-01-01

    results of these in vitro studies do not provide strong evidence to support the use of selective substrate adhesion as a means to isolate chondroprogenitor cells, the findings demonstrate the potential of combining a growth factor delivery hydrogel and FI IFP cells as a single stage therapy for cartilage defect repair. PMID:24090441

  3. Femoral hernia repair

    MedlinePlus

    Femorocele repair; Herniorrhaphy; Hernioplasty - femoral ... During surgery to repair the hernia, the bulging tissue is pushed back in. The weakened area is sewn closed or strengthened. This repair ...

  4. Undescended testicle repair

    MedlinePlus

    Orchidopexy; Inguinal orchidopexy; Orchiopexy; Repair of undescended testicle; Cryptorchidism repair ... first year of life without treatment. Undescended testicle repair surgery is recommended for patients whose testicles do ...

  5. Nondisjunction of a Single Chromosome Leads to Breakage and Activation of DNA Damage Checkpoint in G2

    PubMed Central

    Quevedo, Oliver; García-Luis, Jonay; Matos-Perdomo, Emiliano; Aragón, Luis; Machín, Félix

    2012-01-01

    The resolution of chromosomes during anaphase is a key step in mitosis. Failure to disjoin chromatids compromises the fidelity of chromosome inheritance and generates aneuploidy and chromosome rearrangements, conditions linked to cancer development. Inactivation of topoisomerase II, condensin, or separase leads to gross chromosome nondisjunction. However, the fate of cells when one or a few chromosomes fail to separate has not been determined. Here, we describe a genetic system to induce mitotic progression in the presence of nondisjunction in yeast chromosome XII right arm (cXIIr), which allows the characterisation of the cellular fate of the progeny. Surprisingly, we find that the execution of karyokinesis and cytokinesis is timely and produces severing of cXIIr on or near the repetitive ribosomal gene array. Consequently, one end of the broken chromatid finishes up in each of the new daughter cells, generating a novel type of one-ended double-strand break. Importantly, both daughter cells enter a new cycle and the damage is not detected until the next G2, when cells arrest in a Rad9-dependent manner. Cytologically, we observed the accumulation of damage foci containing RPA/Rad52 proteins but failed to detect Mre11, indicating that cells attempt to repair both chromosome arms through a MRX-independent recombinational pathway. Finally, we analysed several surviving colonies arising after just one cell cycle with cXIIr nondisjunction. We found that aberrant forms of the chromosome were recovered, especially when RAD52 was deleted. Our results demonstrate that, in yeast cells, the Rad9-DNA damage checkpoint plays an important role responding to compromised genome integrity caused by mitotic nondisjunction. PMID:22363215

  6. Intestinal obstruction repair

    MedlinePlus

    Repair of volvulus; Intestinal volvulus - repair; Bowel obstruction - repair ... Intestinal obstruction repair is done while you are under general anesthesia . This means you are asleep and DO NOT feel pain. ...

  7. Motorcycle Repair.

    ERIC Educational Resources Information Center

    Hein, Jim; Bundy, Mike

    This motorcycle repair curriculum guide contains the following ten areas of study: brake systems, clutches, constant mesh transmissions, final drives, suspension, mechanical starting mechanisms, electrical systems, fuel systems, lubrication systems, and overhead camshafts. Each area consists of one or more units of instruction. Each instructional…

  8. Outboard Repair.

    ERIC Educational Resources Information Center

    Hardway, Jack

    This consortium-developed instructor's manual for small engine repair (with focus on outboard motors) consists of the following nine instructional units: electrical remote control assembly, mechanical remote control assembly, tilt assemblies, exhaust housing, propeller and trim tabs, cooling system, mechanical gearcase, electrical gearcase, and…

  9. Snowmobile Repair.

    ERIC Educational Resources Information Center

    Helbling, Wayne

    This guide is designed to provide and/or improve instruction for occupational training in the area of snowmobile repair, and includes eight areas. Each area consists of one or more units of instruction, with each instructional unit including some or all of the following basic components: Performance objectives, suggested activities for teacher and…

  10. Influence of a single-nucleotide polymorphism of the DNA mismatch repair-related gene exonuclease-1 (rs9350) with prostate cancer risk among Chinese people.

    PubMed

    Zhang, Yiming; Li, Pengju; Xu, Abai; Chen, Jie; Ma, Chao; Sakai, Akiko; Xie, Liping; Wang, Lei; Na, Yanqun; Kaku, Haruki; Xu, Peng; Jin, Zhong; Li, Xiezhao; Guo, Kai; Shen, Haiyan; Zheng, Shaobo; Kumon, Hiromi; Liu, Chunxiao; Huang, Peng

    2016-05-01

    In this study, we aimed to identify the influence of exonuclease 1 (EXO1) single-nucleotide polymorphism rs9350, which is involved in DNA mismatch repair, on prostate cancer risk in Chinese people. In our hospital-based case-control study, 214 prostate cancer patients and 253 cancer-free control subjects were enrolled from three hospitals in China. Genotyping for rs9350 was performed by the SNaPshot(®) method using peripheral blood samples. Consequently, a significantly higher prostate cancer risk was observed in patients with the CC genotype [odds ratio (OR) = 1.678, 95 % confidence interval (CI) = 1.130-2.494, P = 0.010] than in those with the CT genotype. Further, the CT/TT genotypes were significantly associated with increased prostate cancer risk (adjusted OR = 1.714, 95 % CI = 1.176-2.500, P = 0.005), and the C allele had a statistically significant compared with T allele (P = 0.009) of EXO1 (rs9350). Through stratified analysis, significant associations were revealed for the CT/TT genotype in the subgroup with diagnosis age >72 (adjusted OR = 1.776, 95 % CI = 1.051-3.002, P = 0.032) and in patients with localized disease subgroup (adjusted OR = 1.798, 95 % CI = 1.070-3.022, P = 0.027). In addition, we observed that patients with prostate-specific antigen (PSA) levels of ≤10 ng/mL were more likely to have the CT/TT genotypes than those with PSA levels of >10 ng/mL (P = 0.006). For the first time, we present evidence that the inherited EXO1 polymorphism rs9350 may have a substantial influence on prostate cancer risk in Chinese people. We believe that the rs9350 could be a useful biomarker for assessing predisposition for and early diagnosis of prostate cancer.

  11. Brc1-dependent recovery from replication stress

    PubMed Central

    Bass, Kirstin L.; Murray, Johanne M.; O'Connell, Matthew J.

    2012-01-01

    BRCT-containing protein 1 (Brc1) is a multi-BRCT (BRCA1 carboxyl terminus) domain protein in Schizosaccharomyces pombe that is required for resistance to chronic replicative stress, but whether this reflects a repair or replication defect is unknown and the subject of this study. We show that brc1Δ cells are significantly delayed in recovery from replication pausing, though this does not activate a DNA damage checkpoint. DNA repair and recombination protein Rad52 is a homologous recombination protein that loads the Rad51 recombinase at resected double-stranded DNA (dsDNA) breaks and is also recruited to stalled replication forks, where it may stabilize structures through its strand annealing activity. Rad52 is required for the viability of brc1Δ cells, and brc1Δ cells accumulate Rad52 foci late in S phase that are potentiated by replication stress. However, these foci contain the single-stranded DNA (ssDNA) binding protein RPA, but not Rad51 or γH2A. Further, these foci are not associated with increased recombination between repeated sequences, or increased post-replication repair. Thus, these Rad52 foci do not represent sites of recombination. Following the initiation of DNA replication, the induction of these foci by replication stress is suppressed by defects in origin recognition complex (ORC) function, which is accompanied by loss of viability and severe mitotic defects. This suggests that cells lacking Brc1 undergo an ORC-dependent rescue of replication stress, presumably through the firing of dormant origins, and this generates RPA-coated ssDNA and recruits Rad52. However, as Rad51 is not recruited, and the checkpoint effector kinase Chk1 is not activated, these structures must not contain the unprotected primer ends found at sites of DNA damage that are required for recombination and checkpoint activation. PMID:22366461

  12. Turbine repair process, repaired coating, and repaired turbine component

    SciTech Connect

    Das, Rupak; Delvaux, John McConnell; Garcia-Crespo, Andres Jose

    2015-11-03

    A turbine repair process, a repaired coating, and a repaired turbine component are disclosed. The turbine repair process includes providing a turbine component having a higher-pressure region and a lower-pressure region, introducing particles into the higher-pressure region, and at least partially repairing an opening between the higher-pressure region and the lower-pressure region with at least one of the particles to form a repaired turbine component. The repaired coating includes a silicon material, a ceramic matrix composite material, and a repaired region having the silicon material deposited on and surrounded by the ceramic matrix composite material. The repaired turbine component a ceramic matrix composite layer and a repaired region having silicon material deposited on and surrounded by the ceramic matrix composite material.

  13. Comparison of repair of DNA double-strand breaks in identical sequences in primary human fibroblast and immortal hamster-human hybrid cells harboring a single copy of human chromosome 11

    NASA Technical Reports Server (NTRS)

    Fouladi, B.; Waldren, C. A.; Rydberg, B.; Cooper, P. K.; Chatterjee, A. (Principal Investigator)

    2000-01-01

    We have optimized a pulsed-field gel electrophoresis assay that measures induction and repair of double-strand breaks (DSBs) in specific regions of the genome (Lobrich et al., Proc. Natl. Acad. Sci. USA 92, 12050-12054, 1995). The increased sensitivity resulting from these improvements makes it possible to analyze the size distribution of broken DNA molecules immediately after the introduction of DSBs and after repair incubation. This analysis shows that the distribution of broken DNA pieces after exposure to sparsely ionizing radiation is consistent with the distribution expected from randomly induced DSBs. It is apparent from the distribution of rejoined DNA pieces after repair incubation that DNA ends continue to rejoin between 3 and 24 h postirradiation and that some of these rejoining events are in fact misrejoining events, since novel restriction fragments both larger and smaller than the original fragment are generated after repair. This improved assay was also used to study the kinetics of DSB rejoining and the extent of misrejoining in identical DNA sequences in human GM38 cells and human-hamster hybrid A(L) cells containing a single human chromosome 11. Despite the numerous differences between these cells, which include species and tissue of origin, levels of TP53, expression of telomerase, and the presence or absence of a homologous chromosome for the restriction fragments examined, the kinetics of rejoining of radiation-induced DSBs and the extent of misrejoining were similar in the two cell lines when studied in the G(1) phase of the cell cycle. Furthermore, DSBs were removed from the single-copy human chromosome in the hamster A(L) cells with similar kinetics and misrejoining frequency as at a locus on this hybrid's CHO chromosomes.

  14. Ring-shaped architecture of RecR: implications for its role in homologous recombinational DNA repair.

    PubMed

    Lee, Byung Il; Kim, Kyoung Hoon; Park, Soo Jeong; Eom, Soo Hyun; Song, Hyun Kyu; Suh, Se Won

    2004-05-19

    RecR, together with RecF and RecO, facilitates RecA loading in the RecF pathway of homologous recombinational DNA repair in procaryotes. The human Rad52 protein is a functional counterpart of RecFOR. We present here the crystal structure of RecR from Deinococcus radiodurans (DR RecR). A monomer of DR RecR has a two-domain structure: the N-terminal domain with a helix-hairpin-helix (HhH) motif and the C-terminal domain with a Cys4 zinc-finger motif, a Toprim domain and a Walker B motif. Four such monomers form a ring-shaped tetramer of 222 symmetry with a central hole of 30-35 angstroms diameter. In the crystal, two tetramers are concatenated, implying that the RecR tetramer is capable of opening and closing. We also show that DR RecR binds to both dsDNA and ssDNA, and that its HhH motif is essential for DNA binding. PMID:15116069

  15. Effect of cleft palate repair on the susceptibility to contraction-induced injury of single permeabilized muscle fibers from congenitally-clefted goat palates.

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Despite cleft palate repair, velopharyngeal competence is not achieved in ~ 15% of patients, often necessitating secondary surgical correction. Velopharyngeal competence postrepair may require the conversion of levator veli palatini muscle fibers from injury-susceptible type 2 fibers to injury-resi...

  16. A comparative study on trans-umbilical single-port laparoscopic approach versus conventional repair for incarcerated inguinal hernia in children

    PubMed Central

    Jun, Zhang; Juntao, Ge; Shuli, Liu; Li, Long

    2016-01-01

    PURPOSE: The purpose of this study is to determine whether singleport laparoscopic repair (SLR) for incarcerated inguinal hernia in children is superior toconventional repair (CR) approaches. METHOD: Between March 2013 and September 2013, 126 infants and children treatedwere retrospectively reviewed. All the patients were divided into three groups. Group A (48 patients) underwent trans-umbilical SLR, group B (36 patients) was subjected to trans-umbilical conventional two-port laparoscopic repair (TLR) while the conventional open surgery repair (COR) was performed in group C (42 patients). Data regarding the operating time, bleeding volume, post-operative hydrocele formation, testicular atrophy, cosmetic results, recurrence rate, and duration of hospital stay of the patients were collected. RESULT: All the cases were completed successfully without conversion. The mean operative time for group A was 15 ± 3.9 min and 24 ± 7.2 min for unilateral hernia and bilateral hernia respectively, whereas for group B, it was 13 ± 6.7 min and 23 ± 9.2 min. The mean duration of surgery in group C was 35 ± 5.2 min for unilateral hernia. The recurrence rate was 0% in all the three groups. There were statistically significant differences in theoperating time, bleeding volume, post-operative hydrocele formation, cosmetic results and duration hospital stay between the three groups (P < 0.001). No statistically significant differences between SLR and TLR were observed except the more cosmetic result in SLR. CONCLUSION: SLR is safe and effective, minimally invasive, and is a new technology worth promoting. PMID:27073306

  17. Midterm Outcome of Mitral Valve Repair with Artificial Chordae for Only Posterior Leaflet Disease—Comparison with the Resectional Technique in a Single Institute

    PubMed Central

    Tanabe, Hiroaki; Yamabe, Tsuyoshi; Sasaki, Kenichi; Suma, Hisayoshi

    2015-01-01

    Objective: We compared the midterm results of mitral valve repair with and without leaflet resection, and revealed the effectiveness of this technique, even for in the posterior leaflet alone. Patients: From August 2002 to March 2014, a total of 306 mitral valve repairs were carried out at our hospital. Of these patients, 50 cases did not undergo leaflet resection (Artificial Chordae; Group A) and 56 cases underwent leaflet resection (Resectional; Group R). There were no significant differences in the preoperative profiles. Results: The follow up rate was 98% and 100% respectively. The mean cardiopulmonary bypass time and aortic cross clamp time were not significantly different. The average ring size was significantly larger (p <0.01) in Group A. All cause mortality at 3 years and 8 years was both 97.8% in Group A and was both 98.1% in Group R. Freedom from moderate mitral regurgitation at 3 years was 97.1% and at 8 years was 91.7% in Group A and 97.4% and 94.6% in Group R respectively. There were no cases of mortality, re-operation for recurrent mitral regurgitation, hemolytic anemia and infectious endocarditis. Conclusion: We demonstrated good midterm results in mitral valve repair without leaflet resection. However, further follow-up was needed. PMID:26321265

  18. Brain aneurysm repair

    MedlinePlus

    ... aneurysm repair; Dissecting aneurysm repair; Endovascular aneurysm repair - brain; Subarachnoid hemorrhage - aneurysm ... Your scalp, skull, and the coverings of the brain are opened. A metal clip is placed at ...

  19. Repair Integrity and Clinical Outcomes Following Arthroscopic Rotator Cuff Repair

    PubMed Central

    Williams, Ariel A.; Mark, P.; DiVenere, Jessica Megan; Klinge, Stephen Austin; Arciero, Robert A.; Mazzocca, Augustus D.

    2016-01-01

    Objectives: To prospectively evaluate the effect of early versus delayed motion on repair integrity on 6-month postoperative magnetic resonance imaging (MRI) scans following rotator cuff repair, and to correlate repair integrity with clinical and functional outcomes. We hypothesized that repair integrity would differ between the early and delayed groups and that patients with repair failures would have worse clinical and functional outcomes. Methods: This was a prospective, randomized, single blinded clinical trial comparing an early motion (post-op day 2-3) to a delayed motion (post-op day 28) rehabilitation protocol following arthroscopic repair of isolated supraspinatus tears. All patients underwent MRI at 6 months post-operatively as part of the study protocol. A blinded board-certified and fellowship-trained orthopaedic surgeon (not part of the surgical team) reviewed operative photos and video to confirm the presence of a full thickness supraspinatus tear and to ensure an adequate and consistent repair. The same surgeon along with a blinded sports medicine fellowship-trained musculoskeletal radiologist independently reviewed all MRIs to determine whether the repair was intact at 6 months. Outcome measures were collected by independent evaluators who were also blinded to group assignment. These included the Western Ontario Rotator Cuff (WORC) index, Single Assessment Numeric Evaluation (SANE) ratings, pain scores, sling use, and physical exam data. Enrolled patients were followed at 6 weeks, 6 months, and 1 year. Results: From October 2008 to April 2012, 73 patients met all inclusion criteria and were willing to participate. 36 patients were randomized to delayed motion and 37 were randomized to early motion. The final study group at 6 months consisted of 58 study participants. Postoperative MRIs were obtained on all of these patients at 6 months regardless of whether or not they were progressing as expected. These MRIs demonstrated an overall failure rate of

  20. The deinococcal DdrB protein is involved in an early step of DNA double strand break repair and in plasmid transformation through its single-strand annealing activity

    PubMed Central

    de la Tour, Claire Bouthier; Boisnard, Stéphanie; Norais, Cédric; Toueille, Magali; Bentchikou, Esma; Vannier, Françoise; Cox, Michael M.; Sommer, Suzanne; Servant, Pascale

    2012-01-01

    The Deinococcus radiodurans bacterium exhibits an extreme resistance to ionizing radiation. Here, we investigated the in vivo role of DdrB, a radiation-induced Deinococcus specific protein that was previously shown to exhibit some in vitro properties akin to those of SSB protein from E. coli but also to promote annealing of single stranded DNA. First we report that the deletion of the C-terminal motif of the DdrB protein, which is similar to the SSB C-terminal motif involved in recruitment to DNA of repair proteins, did neither affect cell radioresistance nor DNA binding properties of purified DdrB protein. We show that, in spite of their different quaternary structure, DdrB and SSB occlude the same amount of ssDNA in vitro. We also showed that DdrB is recruited early and transiently after irradiation into the nucleoid to form discrete foci. Absence of DdrB increased the lag phase of the extended synthesis-dependent strand annealing (ESDSA) process, affecting neither the rate of DNA synthesis nor the efficiency of fragment reassembly, as indicated by monitoring DNA synthesis and genome reconstitution in cells exposed to a sub-lethal ionizing radiation dose. Moreover, cells devoid of DdrB were affected in the establishment of plasmid DNA during natural transformation, a process that requires pairing of internalized plasmid single stranded DNA fragments, whereas they were proficient in transformation by a chromosomal DNA marker that integrates into the host chromosome through homologous recombination. Our data are consistent with a model in which DdrB participates in an early step of DNA double strand break repair in cells exposed to very high radiation doses. DdrB might facilitate the accurate assembly of the myriad of small fragments generated by extreme radiation exposure through a single strand annealing (SSA) process to generate suitable substrates for subsequent ESDSA-promoted genome reconstitution. PMID:21968057

  1. DNA Damage and Repair in Eukaryotic Cells

    PubMed Central

    Painter, R. B.

    1974-01-01

    Damage in DNA after irradiation can be classified into five kinds: base damage, single-strand breaks, double-strand breaks, DNA–DNA cross-linking, and DNA-protein cross-linking. Of these, repair of base damage is the best understood. In eukaryotes, at least three repair systems are known that can deal with base damage: photoreactivation, excision repair, and post-replication repair. Photoreactivation is specific for UV-induced damage and occurs widely throughout the biosphere, although it seems to be absent from placental mammals. Excision repair is present in prokaryotes and in animals but does not seem to be present in plants. Post-replication repair is poorly understood. Recent reports indicate that growing points in mammalian DNA simply skip past UV-induced lesions, leaving gaps in newly made DNA that are subsequently filled in by de novo synthesis. Evidence that this concept is oversimplified or incorrect is presented.—Single-strand breaks are induced by ionizing radiation but most cells can rapidly repair most or all of them, even after supralethal doses. The chemistry of the fragments formed when breaks are induced by ionizing radiation is complex and poorly understood. Therefore, the intermediate steps in the repair of single-strand breaks are unknown. Double-strand breaks and the two kinds of cross-linking have been studied very little and almost nothing is known about their mechanisms for repair.—The role of mammalian DNA repair in mutations is not known. Although there is evidence that defective repair can lead to cancer and/or premature aging in humans, the relationship between the molecular defects and the diseased state remains obscure. PMID:4442699

  2. CT Imaging Findings and Their Relevance to the Clinical Outcomes After Stent Graft Repair of Penetrating Aortic Ulcers: Six-year, Single-center Experience

    SciTech Connect

    Shin, Ji Hoon; Angle, John F.; Park, Auh Whan; Anderson, Curtis; Sabri, Saher S.; Turba, Ulku C.; Kern, John A.; Cherry, Kenneth J.; Matsumoto, Alan H.

    2012-12-15

    Purpose: To present the computed tomographic (CT) imaging findings and their relevance to clinical outcomes related to stent graft placement in patients with penetrating aortic ulcers (PAUs). Methods: Medical and imaging records and imaging studies were reviewed for consecutive patients who underwent stent graft repair of a PAU. The distribution and characteristics of the PAU, technical success of stent graft repair, procedure-related complications, associated aortic wall abnormalities, and outcomes of the PAUs at follow-up CT scans were evaluated. Results: Fifteen patients underwent endovascular treatment for PAU. A total of 87% of the PAUs were in the proximal (n = 8) or distal (n = 5) descending thoracic aorta. There was a broad spectrum of PAU depth (mean, 7.9 {+-} 5.6 mm; range 1.5-25.0 mm) and diameter (mean, 13.5 {+-} 9.7 mm; range 2.2-41.0 mm). Atherosclerosis of the thoracic aorta and intramural hematoma were associated in 53 and 93% of the patients, respectively. Technical success was achieved in 100%. Two or more stent grafts were used in five patients. Endoleaks were observed in two patients within 2 weeks of the procedure, both of which resolved spontaneously. At follow-up CT scanning, regression and thrombosis of the PAUs were observed in all patients. The average patient survival was 61.8 months, with an overall mortality of 13% (2 of 15) at follow-up. Neither death was related to the endograft device or the PAU. Conclusion: Endovascular stent graft placement was safe and effective in causing regression and thrombosis of PAUs in this small series of patients. Two or more stent grafts were used in five patients (33%) with associated long-segmental atherosclerotic changes of the thoracic aorta or intramural hematoma.

  3. Long-term efficacy of endovascular vs open surgical repair for complicated type-B aortic dissection: a single-center retrospective study and meta-analysis

    PubMed Central

    Zhu, Y.; Wang, B.; Meng, Q.; Liu, J.; Zhai, S.; He, J.

    2016-01-01

    This study aimed to evaluate the long-term survival and risk factors of traditional open surgical repair (OSR) vs thoracic endovascular aneurysm repair (TEVAR) for complicated type-B aortic dissection (TBAD). A total of 118 inpatients (45 OSR vs 73 TEVAR) with TBAD were enrolled from January 2004 to January 2015. Kaplan-Meier curves and Cox proportional hazards analysis were performed to identify the long-term survival rate and independent predictors of survival, respectively. Meta-analysis was used to further explore the long-term efficacy of OSR and TEVAR in the eight included studies using Review Manager 5.2 software. An overall 10-year survival rate of 41.9% was found, and it was similar in the two groups (56.7% OSR vs 26.1% TEVAR; log-rank P=0.953). The risk factors of long-term survival were refractory hypertension (OR=11.1; 95%CI=1.428-86.372; P=0.021] and preoperative aortic diameter >55 mm (OR=4.5; 95%CI=1.842-11.346; P=0.001). Long-term survival rate did not differ significantly between OSR and TEVAR (hazard ratio=0.87; 95%CI=0.52-1.47; P=0.61). Compared with OSR, TEVAR did not show long-term advantages for patients with TBAD. Refractory hypertension and total aortic diameter >55 mm can be used to predict the long-term survival of TBAD in the Chinese Han population. PMID:27254661

  4. Molecular dosimetry of DNA damage caused by alkylation. II. The induction and repair of different classes of single-strand breaks in cultured mammalian cells treated with ethylating agents.

    PubMed

    Dogliotti, E; Lakhanisky, T; van der Schans, G P; Lohman, P H

    1984-01-01

    Cultured Chinese hamster ovary cells were treated with ethylating agents. DNA lesions giving rise to single-strand breaks (SSB) or alkali-labile sites were measured by elution through membrane filters at pH 12.0 and pH 12.6, and by centrifugation in alkaline sucrose gradients after 1 h and 21 h lysis in alkali. Two agents with different tendencies to ethylate preferentially either at N or O atoms were compared, namely N-ethyl-N'-nitro-N-nitrosoguanidine (ENNG) and diethyl sulphate (DES). The compounds differed greatly in their potency to induce lesions, but the ratios of SSB, measured with different methods after a treatment for 30 min, did not differ significantly. This suggested that the spectrum of lesions induced by the two compounds is very similar. However, when both agents were studied with alkaline elution at pH 12.0 after a short treatment time (5 min) only ENNG was found to induce rapidly-repairable SSB. Most of these were rejoined already within 5 min after treatment. These results suggest that rapidly-repairable lesions occurring in DNA after treatment of mammalian cells with ethylating agents are due mainly to alkylation at O-atoms. PMID:6472317

  5. Escherichia coli RecO protein anneals ssDNA complexed with its cognate ssDNA-binding protein: A common step in genetic recombination.

    PubMed

    Kantake, Noriko; Madiraju, Murty V V M; Sugiyama, Tomohiko; Kowalczykowski, Stephen C

    2002-11-26

    We present biochemical evidence for the functional similarity of Escherichia coli RecO protein and bacteriophage T4 UvsY protein to eukaryotic Rad52 protein. Although Rad52 protein is conserved in eukaryotes, no sequence homologue has been found in prokaryotes or archeabacteria. Rad52 protein has two unique activities: facilitation of replication protein-A (RPA) displacement by Rad51 protein and annealing of RPA-single-stranded DNA (ssDNA) complexes. Both activities require species-specific interaction between Rad52 protein and RPA. Both RecO and UvsY proteins also possess the former property with regard to their cognate ssDNA-binding protein. Here, we report that RecO protein anneals ssDNA that is complexed with only its cognate ssDNA-binding protein, suggesting the involvement of species-specific interactions. Optimal activity for RecO protein occurs after formation of a 1:1 complex with SSB protein. RecR protein, which is known to stimulate RecO protein to facilitate SSB protein displacement by RecA protein, inhibits annealing by RecO protein, suggesting that RecR protein may regulate the choice between the DNA strand invasion versus annealing pathways. In addition, we show that UvsY protein anneals ssDNA; furthermore, ssDNA, which is complexed only with its cognate ssDNA-binding protein, is annealed in the presence of UvsY protein. These results indicate that RecO and possibly UvsY proteins are functional counterparts of Rad52 protein. Based on the conservation of these functions, we propose a modified double-strand break repair model that includes DNA annealing as an important intermediate step. PMID:12438681

  6. Book Repair Manual.

    ERIC Educational Resources Information Center

    Milevski, Robert J.

    1995-01-01

    This book repair manual developed for the Illinois Cooperative Conservation Program includes book structure and book problems, book repair procedures for 4 specific problems, a description of adhesive bindings, a glossary, an annotated list of 11 additional readings, book repair supplies and suppliers, and specifications for book repair kits. (LRW)

  7. The role of DNA double-strand breaks in spontaneous homologous recombination in S. cerevisiae.

    PubMed

    Lettier, Gaëlle; Feng, Qi; de Mayolo, Adriana Antúnez; Erdeniz, Naz; Reid, Robert J D; Lisby, Michael; Mortensen, Uffe H; Rothstein, Rodney

    2006-11-10

    Homologous recombination (HR) is a source of genomic instability and the loss of heterozygosity in mitotic cells. Since these events pose a severe health risk, it is important to understand the molecular events that cause spontaneous HR. In eukaryotes, high levels of HR are a normal feature of meiosis and result from the induction of a large number of DNA double-strand breaks (DSBs). By analogy, it is generally believed that the rare spontaneous mitotic HR events are due to repair of DNA DSBs that accidentally occur during mitotic growth. Here we provide the first direct evidence that most spontaneous mitotic HR in Saccharomyces cerevisiae is initiated by DNA lesions other than DSBs. Specifically, we describe a class of rad52 mutants that are fully proficient in inter- and intra-chromosomal mitotic HR, yet at the same time fail to repair DNA DSBs. The conclusions are drawn from genetic analyses, evaluation of the consequences of DSB repair failure at the DNA level, and examination of the cellular re-localization of Rad51 and mutant Rad52 proteins after introduction of specific DSBs. In further support of our conclusions, we show that, as in wild-type strains, UV-irradiation induces HR in these rad52 mutants, supporting the view that DNA nicks and single-stranded gaps, rather than DSBs, are major sources of spontaneous HR in mitotic yeast cells.

  8. Rapid road repair vehicle

    DOEpatents

    Mara, L.M.

    1998-05-05

    Disclosed is a rapid road repair vehicle capable of moving over a surface to be repaired at near normal posted traffic speeds to scan for and find at the high rate of speed, imperfections in the pavement surface, prepare the surface imperfection for repair by air pressure and vacuum cleaning, applying a correct amount of the correct patching material to effect the repair, smooth the resulting repaired surface, and catalog the location and quality of the repairs for maintenance records of the road surface. The rapid road repair vehicle can repair surface imperfections at lower cost, improved quality, at a higher rate of speed than was not heretofor possible, with significantly reduced exposure to safety and health hazards associated with this kind of road repair activities in the past. 2 figs.

  9. Rapid road repair vehicle

    DOEpatents

    Mara, Leo M.

    1998-01-01

    Disclosed is a rapid road repair vehicle capable of moving over a surface to be repaired at near normal posted traffic speeds to scan for and find an the high rate of speed, imperfections in the pavement surface, prepare the surface imperfection for repair by air pressure and vacuum cleaning, applying a correct amount of the correct patching material to effect the repair, smooth the resulting repaired surface, and catalog the location and quality of the repairs for maintenance records of the road surface. The rapid road repair vehicle can repair surface imperfections at lower cost, improved quality, at a higher rate of speed than was was heretofor possible, with significantly reduced exposure to safety and health hazards associated with this kind of road repair activities in the past.

  10. DNA Mismatch Repair

    PubMed Central

    MARINUS, M. G.

    2014-01-01

    DNA mismatch repair functions to correct replication errors in newly synthesized DNA and to prevent recombination between related, but not identical (homeologous), DNA sequences. The mechanism of mismatch repair is best understood in Escherichia coli and is the main focus of this review. The early genetic studies of mismatch repair are described as a basis for the subsequent biochemical characterization of the system. The effects of mismatch repair on homologous and homeologous recombination are described. The relationship of mismatch repair to cell toxicity induced by various drugs is included. The VSP (Very Short Patch) repair system is described in detail. PMID:26442827

  11. Association between single nucleotide polymorphisms (SNPs) of XRCC2 and XRCC3 homologous recombination repair genes and ovarian cancer in Polish women.

    PubMed

    Michalska, Magdalena M; Samulak, Dariusz; Romanowicz, Hanna; Jabłoński, Filip; Smolarz, Beata

    2016-04-01

    The variability, perceived in DNA repair genes, may be of clinical importance for evaluation of the risk of occurrence of a given type of cancer, its prophylactics and therapy. The aim of the present work was to evaluate associations between the risk of ovarian cancer and polymorphisms in the genes, encoding for two key proteins of homologous recombination: XRCC2 Arg188His (c. 563 G>A; rs3218536) and XRCC3 Thr241Met (c. 722 C>T; rs861539). The study consisted of 700 patients with ovarian cancer and 700 healthy subjects. Analysis of the gene polymorphisms was performed using PCR-RFLP (restriction length fragment polymorphism). We found a statistically significant increase of the 188His allele frequency (OR=4.01; 95% CI=3.40-4.72; p<.0001) of XRCC2 in ovarian cancer compared to healthy controls. There were no differences in the genotype and allele distributions and odds ratios of the XRCC3 Thr241Met polymorphism between patient and control groups. Association of these genetic polymorphisms with histological grading showed increased XRCC2 188Arg/His (OR=33.0; 95% CI=14.51-75.05; p<.0001) and 188His/His genotypes (OR=9.37; 95% CI=4.79-18.32; p<.0001) and XRCC3 241Thr/Met (OR=24.28; 95% CI=12.38-47.61; p<.0001) and 241Met/Met genotype frequencies (OR=17.00; 95% CI=8.42-34.28; p<.0001) in grading 1 (G1) as well as 188His (OR=2.78; 95% CI=2.11-3.69; p<.0001) and 241Met allele overrepresentation (OR=2.59; 95% CI=2.08-3.22; p<.0001) in G1 ovarian patients. Finally, with clinical FIGO staging under evaluation, an increase in XRCC2 188His/His homozygote and 188Arg/His heterozygote frequencies in staging I (SI) and XRCC3 Thr/Met heterozygote frequencies in SI was observed. The obtained results indicate that XRCC2 Arg188His and XRCC3 Thr241Met polymorphisms may be positively associated with the incidence of ovarian carcinoma in the population of Polish women.

  12. Replication protein A is required for meiotic recombination in Saccharomyces cerevisiae.

    PubMed Central

    Soustelle, Christine; Vedel, Michèle; Kolodner, Richard; Nicolas, Alain

    2002-01-01

    In Saccharomyces cerevisiae, meiotic recombination is initiated by transient DNA double-stranded breaks (DSBs). These DSBs undergo a 5' --> 3' resection to produce 3' single-stranded DNA ends that serve to channel DSBs into the RAD52 recombinational repair pathway. In vitro studies strongly suggest that several proteins of this pathway--Rad51, Rad52, Rad54, Rad55, Rad57, and replication protein A (RPA)--play a role in the strand exchange reaction. Here, we report a study of the meiotic phenotypes conferred by two missense mutations affecting the largest subunit of RPA, which are localized in the protein interaction domain (rfa1-t11) and in the DNA-binding domain (rfa1-t48). We find that both mutant diploids exhibit reduced sporulation efficiency, very poor spore viability, and a 10- to 100-fold decrease in meiotic recombination. Physical analyses indicate that both mutants form normal levels of meiosis-specific DSBs and that the broken ends are processed into 3'-OH single-stranded tails, indicating that the RPA complex present in these rfa1 mutants is functional in the initial steps of meiotic recombination. However, the 5' ends of the broken fragments undergo extensive resection, similar to what is observed in rad51, rad52, rad55, and rad57 mutants, indicating that these RPA mutants are defective in the repair of the Spo11-dependent DSBs that initiate homologous recombination during meiosis. PMID:12072452

  13. Laparoscopic Inguinal Hernia Repair

    MedlinePlus

    ... Some hernia repairs are performed using a small telescope known as a laparoscope. If your surgeon has ... in the abdominal wall (muscle) using small incisions, telescopes and a patch (mesh). Laparoscopic repair offers a ...

  14. Eye muscle repair - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000111.htm Eye muscle repair - discharge To use the sharing features on ... enable JavaScript. You or your child had eye muscle repair surgery to correct eye muscle problems that ...

  15. Hydrocele repair - series (image)

    MedlinePlus

    ... vaginalis into the scrotum. This is called an inguinal hernia. If a hydrocele persists past the first six ... months of life, it should be surgically repaired. Inguinal hernia in infants is usually repaired within the first ...

  16. The Saccharomyces cerevisiae RAD7 and RAD16 genes are required for inducible excision of endonuclease III sensitive-sites, yet are not needed for the repair of these lesions following a single UV dose.

    PubMed

    Scott, A D; Waters, R

    1997-01-31

    The RAD7 and RAD16 genes of Saccharomyces cerevisiae have roles in the repair of UV induced CPDs in nontranscribed genes [1], and in the repair of CPDs in the nontranscribed strand of transcribed genes [2]. Previously, we identified an inducible component to nucleotide excision repair (NER), which is absent in a rad16 delta strain [3]. We have examined the repair of UV induced endonuclease III sensitive-sites (EIIISS), and have shown repair of these lesions to proceed by NER but their removal from nontranscribed regions is independent of RAD7 and RAD16. Furthermore, EIIISS are repaired with equal efficiency from both transcribed and nontranscribed genes [4]. In order to dissect the roles of RAD7 and RAD16 in the above processes we examined the repair of EIIISS in the MAT alpha and HML alpha loci, which are, respectively, transcriptionally active and inactive in alpha haploid cells. These loci have elevated levels of these lesions after UV (in genomic DNA EIIISS constitute about 10% of total lesions, whereas CPDs are about 70% of total lesions). We have shown that excision of UV induced EIIISS is enhanced following a prior UV irradiation. No enhancement of repair was detected in either the rad7 delta or the rad16 delta mutant. The fact that RAD7 and RAD16 are not required for the repair of EIIISS per se yet are required for the enhanced excision of these lesions from MAT alpha and HML alpha suggests two possibilities. These genes have two roles in NER, namely in the repair of CPDs from nontranscribed sequences, and in enhancing NER itself regardless of whether these genes' products are required for the excision of the specific lesion being repaired. In the latter case, the induction of RAD7 and RAD16 may increase the turnover of complexes stalled in nontranscribed DNA so as to increase the availability of NER proteins for the repair of CPDs and EIIISS in all regions of the genome.

  17. Pectoralis Major Tendon Repair

    PubMed Central

    Cordasco, Frank A.; Degen, Ryan; Mahony, Gregory Thomas; Tsouris, Nicholas

    2016-01-01

    Objectives: Systematic reviews of the literature have identified 365 reported cases of Pectoralis Major Tendon (PMT) injuries. While surgical treatment has demonstrated improved outcomes compared to non-operative treatment, there is still relatively limited data on the functional outcome, return to sport and need for 2nd surgery in athletes following PMT repair. This study comprises the largest series of athletes following PMT repair reported to date. The Objective is to report on the functional outcomes, return to sport and need for 2nd surgery in a consecutive series of PMT tears. Methods: From 2009, 81 patients with PMT tears were enrolled in this prospective series. Baseline evaluation included patient demographics, mechanism of injury, physical examination and PMT specific MRI for confirmation of the diagnosis and analysis of the extent of injury. Each patient underwent surgical repair by the senior author utilizing a previously published surgical technique. Patients were then followed at 2 weeks, 6 weeks, 3 months and 6 months and further follow-up was conducted annually thereafter with functional outcome scores and adduction strength testing. The return to sport and incidence of 2nd surgery data were recorded. This study includes the first 40 athletes to reach the 2-year post-operative period. Results: All athletes were male, with an average age of 34.4 years (range 23-59). The patient cohort consisted of 4 professional NFL players and 36 recreational athletes. Average follow-up duration was 2.5 years (range 2 - 6.0 years). The most common mechanisms of injury occurred during the bench press (n=26) and contact sport participation (n=14). Sixteen injuries were complete avulsions involving both the clavicular and sternocostal heads, while 24 were isolated sternocostal head avulsions. Average pre-injury bench press of 396 lbs (range 170-500 lbs) was restored to 241 lbs post-operatively (range 140-550 lbs). Single Assessment Numeric Evaluation (SANE) scores

  18. Optimal inventories for overhaul of repairable redundant systems - A Markov decision model

    NASA Technical Reports Server (NTRS)

    Schaefer, M. K.

    1984-01-01

    A Markovian decision model was developed to calculate the optimal inventory of repairable spare parts for an avionics control system for commercial aircraft. Total expected shortage costs, repair costs, and holding costs are minimized for a machine containing a single system of redundant parts. Transition probabilities are calculated for each repair state and repair rate, and optimal spare parts inventory and repair strategies are determined through linear programming. The linear programming solutions are given in a table.

  19. Single nucleotide polymorphisms (SNPs) of hOGG1 and XRCC1 DNA repair genes and the risk of ovarian cancer in Polish women.

    PubMed

    Michalska, Magdalena M; Samulak, Dariusz; Romanowicz, Hanna; Bieńkiewicz, Jan; Sobkowski, Maciej; Ciesielski, Krzysztof; Smolarz, Beata

    2015-12-01

    The aim of this study was to determine single nucleotide polymorphisms in hOGG1 (Ser326Cys (rs13181)) and XRCC1 (Arg194Trp (rs1799782)) genes, respectively, and to identify the correlation between them and the overall risk, grading and staging of ovarian cancer in Polish women. Our study comprised 720 patients diagnosed with ovarian cancer and 720 healthy controls. The genotype analysis of hOGG1 and XRCC1 polymorphisms was performed using polymerase chain reaction (PCR)-based restriction fragment length polymorphism (PCR-RFLP). Odds ratios (OR) and 95 % confidence intervals (CI) for each genotype and allele were calculated. Results revealed an association between hOGG1 Ser326Cys polymorphism and the incidence of ovarian cancer. Variant Cys allele of hOGG1 increased the overall cancer risk (OR 2.89; 95 % CI 2.47-3.38; p < .0001). Moreover, ovarian cancer grading remained in a relationship with both analysed polymorphisms; G1 tumours presented increased frequencies of hOGG1 Cys/Cys homozygotes (OR 18.33; 95 % CI 9.38-35.81; p < .0001) and XRCC1 Trp/Trp homozygotes (OR 20.50; 95 % CI 10.17-41.32; p < .0001). Furthermore, G1 ovarian cancers displayed an overrepresentation of Cys and Trp allele. In conclusion, hOGG1 Ser326Cys and XRCC1 Arg194Trp polymorphisms may be regarded as risk factors of ovarian cancer.

  20. A Microstructure Evolution Model for the Processing of Single-Crystal Alloy CMSX-4 Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair (Part II)

    NASA Astrophysics Data System (ADS)

    Acharya, Ranadip; Bansal, Rohan; Gambone, Justin J.; Das, Suman

    2014-12-01

    Part I [Metall. Mater. Trans. B, 2014, DOI:10.1007/s11663-014-0117-9] presented a comprehensive thermal, fluid flow, and solidification model that can predict the temperature distribution and flow characteristics for the processing of CMSX-4 alloy powder through scanning laser epitaxy (SLE). SLE is an additive manufacturing technology aimed at the creation of equiaxed, directionally solidified and single-crystal (SX) deposits of nickel-based superalloys using a fast-scanning laser beam. Part II here further explores the Marangoni convection-based model to predict the solidification microstructure as a function of the conditions at the trailing edge of the melt pool formed during the SLE process. Empirical values for several microstructural characteristics such as the primary dendrite arm spacing (PDAS), the columnar-to-equiaxed transition (CET) criterion and the oriented-to-misoriented transition (OMT) criterion are obtained. Optical microscopy provides visual information on the various microstructural characteristics of the deposited material such as melt depth, CET location, OMT location, PDAS, etc. A quantitative and consistent investigation of this complex set of characteristics is both challenging and unprecedented. A customized image-analysis technique based on active contouring is developed to automatically extract these data from experimental micrographs. Quantitative metallography verifies that even for the raster scan pattern in SLE and the corresponding line heat source assumption, the PDAS follows the growth relation w ~ G -0.5 V -0.25 ( w = PDAS, G = temperature gradient and V = solidification velocity) developed for marginal stability under constrained growth. Models for the CET and OMT are experimentally validated, thereby providing powerful predictive capabilities for controlling the microstructure of SX alloys processed through SLE.

  1. Optimality in DNA repair.

    PubMed

    Richard, Morgiane; Fryett, Matthew; Miller, Samantha; Booth, Ian; Grebogi, Celso; Moura, Alessandro

    2012-01-01

    DNA within cells is subject to damage from various sources. Organisms have evolved a number of mechanisms to repair DNA damage. The activity of repair enzymes carries its own risk, however, because the repair of two nearby lesions may lead to the breakup of DNA and result in cell death. We propose a mathematical theory of the damage and repair process in the important scenario where lesions are caused in bursts. We use this model to show that there is an optimum level of repair enzymes within cells which optimises the cell's response to damage. This optimal level is explained as the best trade-off between fast repair and a low probability of causing double-stranded breaks. We derive our results analytically and test them using stochastic simulations, and compare our predictions with current biological knowledge. PMID:21945337

  2. Mfd as a central partner of transcription coupled repair.

    PubMed

    Monnet, Jordan; Grange, Wilfried; Strick, Terence R; Joly, Nicolas

    2013-01-01

    Transcription-coupled repair (TCR) is one of the key of the nucleotide excision repair (NER) pathways required to preserve genome integrity. Although understanding TCR is still a major challenge, recent single-molecule experiments have brought new insights into the initial steps of TCR leading to new perspectives.

  3. Laparoscopic lumbar hernia repair.

    PubMed

    Madan, Atul K; Ternovits, Craig A; Speck, Karen E; Pritchard, F Elizabeth; Tichansky, David S

    2006-04-01

    Lumbar hernias are rare clinical entities that often pose a challenge for repair. Because of the surrounding anatomy, adequate surgical herniorraphy is often difficult. Minimally invasive surgery has become an option for these hernias. Herein, we describe two patients with lumbar hernias (one with a recurrent traumatic hernia and one with an incisional hernia). Both of these hernias were successfully repaired laparoscopically.

  4. Snowmobile Repair. Teacher Edition.

    ERIC Educational Resources Information Center

    Hennessy, Stephen S.; Conrad, Rex

    This teacher's guide contains 14 units on snowmobile repair: (1) introduction to snowmobile repair; (2) skis, front suspension, and steering; (3) drive clutch; (4) drive belts; (5) driven clutch; (6) chain drives; (7) jackshafts and axles; (8) rear suspension; (9) tracks; (10) shock absorbers; (11) brakes; (12) engines; (13) ignition and…

  5. Animal models of cartilage repair

    PubMed Central

    Cook, J. L.; Hung, C. T.; Kuroki, K.; Stoker, A. M.; Cook, C. R.; Pfeiffer, F. M.; Sherman, S. L.; Stannard, J. P.

    2014-01-01

    Cartilage repair in terms of replacement, or regeneration of damaged or diseased articular cartilage with functional tissue, is the ‘holy grail’ of joint surgery. A wide spectrum of strategies for cartilage repair currently exists and several of these techniques have been reported to be associated with successful clinical outcomes for appropriately selected indications. However, based on respective advantages, disadvantages, and limitations, no single strategy, or even combination of strategies, provides surgeons with viable options for attaining successful long-term outcomes in the majority of patients. As such, development of novel techniques and optimisation of current techniques need to be, and are, the focus of a great deal of research from the basic science level to clinical trials. Translational research that bridges scientific discoveries to clinical application involves the use of animal models in order to assess safety and efficacy for regulatory approval for human use. This review article provides an overview of animal models for cartilage repair. Cite this article: Bone Joint Res 2014;4:89–94. PMID:24695750

  6. INTERNAL REPAIR OF PIPELINES

    SciTech Connect

    Bill Bruce; Nancy Porter; George Ritter; Matt Boring; Mark Lozev; Ian Harris; Bill Mohr; Dennis Harwig; Robin Gordon; Chris Neary; Mike Sullivan

    2005-07-20

    The two broad categories of fiber-reinforced composite liner repair and deposited weld metal repair technologies were reviewed and evaluated for potential application for internal repair of gas transmission pipelines. Both are used to some extent for other applications and could be further developed for internal, local, structural repair of gas transmission pipelines. Principal conclusions from a survey of natural gas transmission industry pipeline operators can be summarized in terms of the following performance requirements for internal repair: (1) Use of internal repair is most attractive for river crossings, under other bodies of water, in difficult soil conditions, under highways, under congested intersections, and under railway crossings. (2) Internal pipe repair offers a strong potential advantage to the high cost of horizontal direct drilling when a new bore must be created to solve a leak or other problem. (3) Typical travel distances can be divided into three distinct groups: up to 305 m (1,000 ft.); between 305 m and 610 m (1,000 ft. and 2,000 ft.); and beyond 914 m (3,000 ft.). All three groups require pig-based systems. A despooled umbilical system would suffice for the first two groups which represents 81% of survey respondents. The third group would require an onboard self-contained power unit for propulsion and welding/liner repair energy needs. (4) The most common size range for 80% to 90% of operators surveyed is 508 mm (20 in.) to 762 mm (30 in.), with 95% using 558.8 mm (22 in.) pipe. Evaluation trials were conducted on pipe sections with simulated corrosion damage repaired with glass fiber-reinforced composite liners, carbon fiber-reinforced composite liners, and weld deposition. Additional un-repaired pipe sections were evaluated in the virgin condition and with simulated damage. Hydrostatic failure pressures for pipe sections repaired with glass fiber-reinforced composite liner were only marginally greater than that of pipe sections without

  7. Complications of Distal Biceps Tendon Repair

    PubMed Central

    Amin, Nirav H.; Volpi, Alex; Lynch, T. Sean; Patel, Ronak M.; Cerynik, Douglas L.; Schickendantz, Mark S.; Jones, Morgan H.

    2016-01-01

    Background: Anatomic reinsertion of the distal biceps is critical for restoring flexion and supination strength. Single- and double-incision surgical techniques have been reported, analyzing complications and outcomes measures. Which technique results in superior clinical outcomes and the lowest associated complications remains unclear. Hypothesis: We hypothesized that rerupture rates would be similar between the 2 techniques, while nerve complications would be higher for the single-incision technique and heterotopic ossification would be more frequent with the double-incision technique. Study Design: Systematic review and meta-analysis; Level of evidence, 4. Methods: A systematic review was conducted using the PubMed, MEDLINE, Cumulative Index to Nursing and Allied Health Literature (CINAHL), SPORTSDiscus, and the Cochrane Central Register of Controlled Trials databases to identify articles reporting distal biceps ruptures up to August 2013. We included English-language articles on adult patients with a minimum of 3 cases reporting single- and double-incision techniques. Frequencies of each complication as a percentage of total cases were calculated. Fisher exact tests were used to test the association between frequencies for each repair method, with P < .05 considered statistically significant. Odds ratios with 95% CIs were also computed. Results: A total of 87 articles met the inclusion criteria. Lateral antebrachial cutaneous nerve neurapraxia was the most common complication in the single-incision group, occurring in 77 of 785 cases (9.8%). Heterotopic ossification was the most common complication in the double-incision group, occurring in 36 of 498 cases (7.2%). Conclusion: The overall frequency of reported complications is higher for single-incision distal biceps repair than for double-incision repair. The frequencies of rerupture and nerve complications are both higher for single-incision repairs while the frequency of heterotopic ossification is higher for

  8. INTERNAL REPAIR OF PIPELINES

    SciTech Connect

    Robin Gordon; Bill Bruce; Ian Harris; Dennis Harwig; George Ritter; Bill Mohr; Matt Boring; Nancy Porter; Mike Sullivan; Chris Neary

    2004-12-31

    The two broad categories of fiber-reinforced composite liner repair and deposited weld metal repair technologies were reviewed and evaluated for potential application for internal repair of gas transmission pipelines. Both are used to some extent for other applications and could be further developed for internal, local, structural repair of gas transmission pipelines. Principal conclusions from a survey of natural gas transmission industry pipeline operators can be summarized in terms of the following performance requirements for internal repair: (1) Use of internal repair is most attractive for river crossings, under other bodies of water, in difficult soil conditions, under highways, under congested intersections, and under railway crossings. (2) Internal pipe repair offers a strong potential advantage to the high cost of horizontal direct drilling when a new bore must be created to solve a leak or other problem. (3) Typical travel distances can be divided into three distinct groups: up to 305 m (1,000 ft.); between 305 m and 610 m (1,000 ft. and 2,000 ft.); and beyond 914 m (3,000 ft.). All three groups require pig-based systems. A despooled umbilical system would suffice for the first two groups which represents 81% of survey respondents. The third group would require an onboard self-contained power unit for propulsion and welding/liner repair energy needs. (4) The most common size range for 80% to 90% of operators surveyed is 508 mm (20 in.) to 762 mm (30 in.), with 95% using 558.8 mm (22 in.) pipe. Evaluation trials were conducted on pipe sections with simulated corrosion damage repaired with glass fiber-reinforced composite liners, carbon fiber-reinforced composite liners, and weld deposition. Additional un-repaired pipe sections were evaluated in the virgin condition and with simulated damage. Hydrostatic failure pressures for pipe sections repaired with glass fiber-reinforced composite liner were only marginally greater than that of pipe sections without

  9. DNA repair variants and breast cancer risk.

    PubMed

    Grundy, Anne; Richardson, Harriet; Schuetz, Johanna M; Burstyn, Igor; Spinelli, John J; Brooks-Wilson, Angela; Aronson, Kristan J

    2016-05-01

    A functional DNA repair system has been identified as important in the prevention of tumour development. Previous studies have hypothesized that common polymorphisms in DNA repair genes could play a role in breast cancer risk and also identified the potential for interactions between these polymorphisms and established breast cancer risk factors such as physical activity. Associations with breast cancer risk for 99 single nucleotide polymorphisms (SNPs) from genes in ten DNA repair pathways were examined in a case-control study including both Europeans (644 cases, 809 controls) and East Asians (299 cases, 160 controls). Odds ratios in both additive and dominant genetic models were calculated separately for participants of European and East Asian ancestry using multivariate logistic regression. The impact of multiple comparisons was assessed by correcting for the false discovery rate within each DNA repair pathway. Interactions between several breast cancer risk factors and DNA repair SNPs were also evaluated. One SNP (rs3213282) in the gene XRCC1 was associated with an increased risk of breast cancer in the dominant model of inheritance following adjustment for the false discovery rate (P < 0.05), although no associations were observed for other DNA repair SNPs. Interactions of six SNPs in multiple DNA repair pathways with physical activity were evident prior to correction for FDR, following which there was support for only one of the interaction terms (P < 0.05). No consistent associations between variants in DNA repair genes and breast cancer risk or their modification by breast cancer risk factors were observed. PMID:27060854

  10. DNA repair variants and breast cancer risk.

    PubMed

    Grundy, Anne; Richardson, Harriet; Schuetz, Johanna M; Burstyn, Igor; Spinelli, John J; Brooks-Wilson, Angela; Aronson, Kristan J

    2016-05-01

    A functional DNA repair system has been identified as important in the prevention of tumour development. Previous studies have hypothesized that common polymorphisms in DNA repair genes could play a role in breast cancer risk and also identified the potential for interactions between these polymorphisms and established breast cancer risk factors such as physical activity. Associations with breast cancer risk for 99 single nucleotide polymorphisms (SNPs) from genes in ten DNA repair pathways were examined in a case-control study including both Europeans (644 cases, 809 controls) and East Asians (299 cases, 160 controls). Odds ratios in both additive and dominant genetic models were calculated separately for participants of European and East Asian ancestry using multivariate logistic regression. The impact of multiple comparisons was assessed by correcting for the false discovery rate within each DNA repair pathway. Interactions between several breast cancer risk factors and DNA repair SNPs were also evaluated. One SNP (rs3213282) in the gene XRCC1 was associated with an increased risk of breast cancer in the dominant model of inheritance following adjustment for the false discovery rate (P < 0.05), although no associations were observed for other DNA repair SNPs. Interactions of six SNPs in multiple DNA repair pathways with physical activity were evident prior to correction for FDR, following which there was support for only one of the interaction terms (P < 0.05). No consistent associations between variants in DNA repair genes and breast cancer risk or their modification by breast cancer risk factors were observed.

  11. Arthroscopic Repair of Posterior Meniscal Root Tears

    PubMed Central

    Matheny, Lauren; Moulton, Samuel G.; Dean, Chase S.; LaPrade, Robert F.

    2016-01-01

    Objectives: The purpose of this study was to compare subjective clinical outcomes in patients requiring arthroscopic transtibial pullout repair for posterior meniscus root tears of the medial and lateral menisci. We hypothesized that improvement in function and activity level would be similar among patients undergoing lateral and medial meniscal root repairs. Methods: This study was IRB approved. All patients who underwent posterior meniscal root repair by a single orthopaedic surgeon were included in this study. Detailed operative data were documented at surgery. Patients completed a subjective questionnaire, including Lysholm score, Tegner activity scale, WOMAC, SF-12 and patient satisfaction with outcome, which were collected preoperatively and at a minimum of two years postoperatively. Failure was defined as any patient who underwent revision meniscal root repair or partial meniscectomy following the index surgery. Results: There were 50 patients (16 females, 34 males) with a mean age of 37.8 years (range, 16.6-65.7) and a mean BMI of 27.3 (range, 20.5-49.2) included in this study. Fifteen patients underwent lateral meniscus root repair and 35 patients underwent medial meniscus root repair. Three patients who underwent lateral meniscus root repair required revision meniscus root repair surgery, while no patients who underwent medial meniscus root repair required revision surgery (p=0.26). There was a significant difference in preoperative and postoperative Lysholm score (53 vs. 78) (p<0.001), Tegner activity scale (2.0 vs. 4.0) (p=0.03), SF-12 physical component subscale (38 vs. 50) (p=0.001) and WOMAC (36 vs. 8) (p<0.001) for the total population. Median patient satisfaction with outcome was 9 (range, 1-10). There was no significant difference in mean age between lateral and medial root repair groups (32 vs. 40) (p=0.12) or gender (p=0.19). There was no significant difference in gender between lateral and medial root repair groups (p=0.95). There was a

  12. Repair of mismatched basepairs in mammalian DNA

    SciTech Connect

    Taylor, J.H.; Hare, J.T.

    1991-08-01

    We have concentrated on three specific areas of our research plan. Our greatest emphasis is on the role of single strand nicks in influencing template strand selection in mismatch repair. We have found, that the ability of a nick in one strand to influence which strand is repaired is not a simple function of distance from the mismatched site but rather that an hot spot where a nick is more likely to have an influence can exist. The second line was production of single-genotype heteroduplexes in order to examine independently the repair of T/G and A/C mispairs within the same sequence context as in our mixed mispair preparations. We have shown preparations of supercoiled heteroduplex can be prepared that were exclusively T/G or exclusively A/C at the mispair site. The third effort has been to understand the difference in repair bias of different cell lines or different transfection conditions as it may relate to different repair systems in the cell. We have identified some of the sources of variation, including cell cycle position. We hope to continue this work to more precisely identify the phase of the cell cycle.

  13. INTERNAL REPAIR OF PIPELINES

    SciTech Connect

    Robin Gordon; Bill Bruce; Ian Harris; Dennis Harwig; George Ritter; Bill Mohr; Matt Boring; Nancy Porter; Mike Sullivan; Chris Neary

    2004-08-17

    The two broad categories of fiber-reinforced composite liner repair and deposited weld metal repair technologies were reviewed and evaluated for potential application for internal repair of gas transmission pipelines. Both are used to some extent for other applications and could be further developed for internal, local, structural repair of gas transmission pipelines. Principal conclusions from a survey of natural gas transmission industry pipeline operators can be summarized in terms of the following performance requirements for internal repair: (1) Use of internal repair is most attractive for river crossings, under other bodies of water, in difficult soil conditions, under highways, under congested intersections, and under railway. (2) Internal pipe repair offers a strong potential advantage to the high cost of horizontal direct drilling when a new bore must be created to solve a leak or other problem. (3) Typical travel distances can be divided into three distinct groups: up to 305 m (1,000 ft.); between 305 m and 610 m (1,000 ft. and 2,000 ft.); and beyond 914 m (3,000 ft.). All three groups require pig-based systems. A despooled umbilical system would suffice for the first two groups which represents 81% of survey respondents. The third group would require an onboard self-contained power unit for propulsion and welding/liner repair energy needs. (4) The most common size range for 80% to 90% of operators surveyed is 508 mm (20 in.) to 762 mm (30 in.), with 95% using 558.8 mm (22 in.) pipe. Evaluation trials were conducted on pipe sections with simulated corrosion damage repaired with glass fiber-reinforced composite liners, carbon fiber-reinforced composite liners, and weld deposition. Additional un-repaired pipe sections were evaluated in the virgin condition and with simulated damage. Hydrostatic failure pressures for pipe sections repaired with glass fiber-reinforced composite liner were only marginally greater than that of pipe sections without liners

  14. EUVL Mask Blank Repair

    SciTech Connect

    Barty, A; Mirkarimi, P; Stearns, D G; Sweeney, D; Chapman, H N; Clift, M; Hector, S; Yi, M

    2002-05-22

    EUV mask blanks are fabricated by depositing a reflective Mo/Si multilayer film onto super-polished substrates. Small defects in this thin film coating can significantly alter the reflected field and introduce defects in the printed image. Ideally one would want to produce defect-free mask blanks; however, this may be very difficult to achieve in practice. One practical way to increase the yield of mask blanks is to effectively repair multilayer defects, and to this effect they present two complementary defect repair strategies for use on multilayer-coated EUVL mask blanks. A defect is any area on the mask which causes unwanted variations in EUV dose in the aerial image obtained in a printing tool, and defect repair is correspondingly defined as any strategy that renders a defect unprintable during exposure. The term defect mitigation can be adopted to describe any strategy which renders a critical defect non-critical when printed, and in this regard a non-critical defect is one that does not adversely affect device function. Defects in the patterned absorber layer consist of regions where metal, typically chrome, is unintentionally added or removed from the pattern leading to errors in the reflected field. There currently exists a mature technology based on ion beam milling and ion beam assisted deposition for repairing defects in the absorber layer of transmission lithography masks, and it is reasonable to expect that this technology will be extended to the repair of absorber defects in EUVL masks. However, techniques designed for the repair of absorber layers can not be directly applied to the repair of defects in the mask blank, and in particular the multilayer film. In this paper they present for the first time a new technique for the repair of amplitude defects as well as recent results on the repair of phase defects.

  15. Heteroduplex formation and mismatch repair of the "stuck" mutation during mating-type switching in Saccharomyces cerevisiae.

    PubMed Central

    Ray, B L; White, C I; Haber, J E

    1991-01-01

    We sequenced two alleles of the MATa locus of Saccharomyces cerevisiae that reduce homothallic switching and confer viability to HO rad52 strains. Both the MATa-stk (J. E. Haber, W. T. Savage, S. M. Raposa, B. Weiffenbach, and L. B. Rowe, Proc. Natl. Acad. Sci. USA 77:2824-2828, 1980) and MATa-survivor (R. E. Malone and D. Hyman, Curr. Genet. 7:439-447, 1983) alleles result from a T----A base change at position Z11 of the MAT locus. These strains also contain identical base substitutions at HMRa, so that the mutation is reintroduced when MAT alpha switches to MATa. Mating-type switching in a MATa-stk strain relative to a MATa Z11T strain is reduced at least 50-fold but can be increased by expression of HO from a galactose-inducible promoter. We confirmed by Southern analysis that the Z11A mutation reduced the efficiency of double-strand break formation compared with the Z11T variant; the reduction was more severe in MAT alpha than in MATa. In MAT alpha, the Z11A mutation also creates a mat alpha 1 (sterile) mutation that distinguishes switches of MATa-stk to either MAT alpha or mat alpha 1-stk. Pedigree analysis of cells induced to switch in G1 showed that MATa-stk switched frequently (23% of the time) to produce one mat alpha 1-stk and one MAT alpha progeny. This postswitching segregation suggests that Z11 was often present in heteroduplex DNA that was not mismatch repaired. When mismatch repair was prevented by deletion of the PMS1 gene, there was an increase in the proportion of mat alpha 1-stk/MAT alpha sectors (59%) and in pairs of switched cells that both retained the stk mutation (27%). We conclude that at least one strand of DNA only 4 bp from the HO cut site is not degraded in most of the gene conversion events that accompany MAT switching. Images PMID:1922052

  16. Rapid road repair vehicle

    SciTech Connect

    Mara, L.M.

    1999-09-07

    Disclosed are improvements to a rapid road repair vehicle comprising an improved cleaning device arrangement, two dispensing arrays for filling defects more rapidly and efficiently, an array of pre-heaters to heat the road way surface in order to help the repair material better bond to the repaired surface, a means for detecting, measuring, and computing the number, location and volume of each of the detected surface imperfection, and a computer means schema for controlling the operation of the plurality of vehicle subsystems. The improved vehicle is, therefore, better able to perform its intended function of filling surface imperfections while moving over those surfaces at near normal traffic speeds.

  17. Rapid road repair vehicle

    DOEpatents

    Mara, Leo M.

    1999-01-01

    Disclosed are improvments to a rapid road repair vehicle comprising an improved cleaning device arrangement, two dispensing arrays for filling defects more rapidly and efficiently, an array of pre-heaters to heat the road way surface in order to help the repair material better bond to the repaired surface, a means for detecting, measuring, and computing the number, location and volume of each of the detected surface imperfection, and a computer means schema for controlling the operation of the plurality of vehicle subsystems. The improved vehicle is, therefore, better able to perform its intended function of filling surface imperfections while moving over those surfaces at near normal traffic speeds.

  18. Repairing Thermal Tiles

    NASA Technical Reports Server (NTRS)

    Mccain, C. R., Jr.; Feiler, C. W.

    1984-01-01

    Small chips and depression in surfaces of surface insulation tiles repaired using Ludox colloidal silica solution and silica powder. No waiting time necessary between mixing filler and using it. Patch cures quickly without heat being applied.

  19. Easily repairable networks

    NASA Astrophysics Data System (ADS)

    Fink, Thomas

    2015-03-01

    We introduce a simple class of distribution networks which withstand damage by being repairable instead of redundant. Instead of asking how hard it is to disconnect nodes through damage, we ask how easy it is to reconnect nodes after damage. We prove that optimal networks on regular lattices have an expected cost of reconnection proportional to the lattice length, and that such networks have exactly three levels of structural hierarchy. We extend our results to networks subject to repeated attacks, in which the repairs themselves must be repairable. We find that, in exchange for a modest increase in repair cost, such networks are able to withstand any number of attacks. We acknowledge support from the Defense Threat Reduction Agency, BCG and EU FP7 (Growthcom).

  20. INTERNAL REPAIR OF PIPELINES

    SciTech Connect

    Robin Gordon; Bill Bruce; Ian Harris; Dennis Harwig; Nancy Porter; Mike Sullivan; Chris Neary

    2004-04-12

    The two broad categories of deposited weld metal repair and fiber-reinforced composite liner repair technologies were reviewed for potential application for internal repair of gas transmission pipelines. Both are used to some extent for other applications and could be further developed for internal, local, structural repair of gas transmission pipelines. Preliminary test programs were developed for both deposited weld metal repair and for fiber-reinforced composite liner repair. Evaluation trials have been conducted using a modified fiber-reinforced composite liner provided by RolaTube and pipe sections without liners. All pipe section specimens failed in areas of simulated damage. Pipe sections containing fiber-reinforced composite liners failed at pressures marginally greater than the pipe sections without liners. The next step is to evaluate a liner material with a modulus of elasticity approximately 95% of the modulus of elasticity for steel. Preliminary welding parameters were developed for deposited weld metal repair in preparation of the receipt of Pacific Gas & Electric's internal pipeline welding repair system (that was designed specifically for 559 mm (22 in.) diameter pipe) and the receipt of 559 mm (22 in.) pipe sections from Panhandle Eastern. The next steps are to transfer welding parameters to the PG&E system and to pressure test repaired pipe sections to failure. A survey of pipeline operators was conducted to better understand the needs and performance requirements of the natural gas transmission industry regarding internal repair. Completed surveys contained the following principal conclusions: (1) Use of internal weld repair is most attractive for river crossings, under other bodies of water, in difficult soil conditions, under highways, under congested intersections, and under railway crossings. (2) Internal pipe repair offers a strong potential advantage to the high cost of horizontal direct drilling (HDD) when a new bore must be created to

  1. Imperforate anus repair - slideshow

    MedlinePlus

    ... presentations/100030.htm Imperforate anus repair - series—Normal anatomy To use the sharing features on this page, ... of 4 Overview In individuals with a normal anatomy, the large intestine (colon) empties into a pouch- ...

  2. Timpani Repair and Maintenance.

    ERIC Educational Resources Information Center

    Combs, F. Michael

    1980-01-01

    Rather than focusing on specific brands of timpani, these guidelines for repair cover mechanical problems of a general nature: pedals, dents, unclear tone, and squeaking. Preventive maintenance is discussed. (Author/SJL)

  3. Eye muscle repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100062.htm Eye muscle repair - series—Normal anatomy To use the sharing ... the eyeball to the eye socket. The external muscles of the eye are found behind the conjunctiva. ...

  4. Laparoscopic Ventral Hernia Repair

    MedlinePlus

    ... the likelihood of a hernia including persistent coughing, difficulty with bowel movements or urination, or frequent need for straining. What are the Advantages of Laparoscopic Ventral Hernia Repair? Keep reading... Page 1 of 2 1 2 » Brought to ...

  5. Human DNA repair genes.

    PubMed

    Wood, R D; Mitchell, M; Sgouros, J; Lindahl, T

    2001-02-16

    Cellular DNA is subjected to continual attack, both by reactive species inside cells and by environmental agents. Toxic and mutagenic consequences are minimized by distinct pathways of repair, and 130 known human DNA repair genes are described here. Notable features presently include four enzymes that can remove uracil from DNA, seven recombination genes related to RAD51, and many recently discovered DNA polymerases that bypass damage, but only one system to remove the main DNA lesions induced by ultraviolet light. More human DNA repair genes will be found by comparison with model organisms and as common folds in three-dimensional protein structures are determined. Modulation of DNA repair should lead to clinical applications including improvement of radiotherapy and treatment with anticancer drugs and an advanced understanding of the cellular aging process. PMID:11181991

  6. Planning Maintenance and Repairs.

    ERIC Educational Resources Information Center

    Fitzemeyer, Ted

    2001-01-01

    Discusses the use of school facility design as an aid to efficiently repairing and maintaining facility systems. Also presents details on facility design's influence in properly maintaining mechanical and electrical systems. (GR)

  7. Patent urachus repair

    MedlinePlus

    Patent urachal tube repair ... belly. Next, the surgeon will find the urachal tube and remove it. The bladder opening will be ... surgeon uses the tools to remove the urachal tube and close off the bladder and area where ...

  8. Achilles tendon repair

    MedlinePlus

    Achilles tendon rupture-surgery; Percutaneous Achilles tendon rupture repair ... To fix your torn Achilles tendon, the surgeon will: Make a cut down the back of your heel Make several small cuts rather than one large cut ...

  9. Repairing ceramic insulating tiles

    NASA Technical Reports Server (NTRS)

    Dunn, B. R.; Laymance, E. L.

    1980-01-01

    Fused-silica tiles containing large voids or gauges are repaired without adhesives by plug insertion method. Tiles are useful in conduits for high-temperature gases, in furnaces, and in other applications involving heat insulation.

  10. Repairing Foam Insulation

    NASA Technical Reports Server (NTRS)

    Corbin, J.; Buras, D.

    1986-01-01

    Large holes in polyurethane foam insulation repaired reliably by simple method. Little skill needed to apply method, used for overhead repairs as well as for those in other orientations. Plug positioned in hole to be filled and held in place with mounting fixture. Fresh liquid foam injected through plug to bond it in place. As foam cures and expands, it displaces plug outward. Protrusion later removed.

  11. Robotic inguinal hernia repair.

    PubMed

    Escobar Dominguez, Jose E; Gonzalez, Anthony; Donkor, Charan

    2015-09-01

    Inguinal hernias have been described throughout the history of medicine with many efforts to achieve the cure. Currently, with the advantages of minimally invasive surgery, new questions arise: what is going to be the best approach for inguinal hernia repair? Is there a real benefit with the robotic approach? Should minimally invasive hernia surgery be the standard of care? In this report we address these questions by describing our experience with robotic inguinal hernia repair. PMID:26153353

  12. Variation in Base Excision Repair Capacity

    PubMed Central

    Wilson, David M.; Kim, Daemyung; Berquist, Brian R.; Sigurdson, Alice J.

    2010-01-01

    The major DNA repair pathway for coping with spontaneous forms of DNA damage, such as natural hydrolytic products or oxidative lesions, is base excision repair (BER). In particular, BER processes mutagenic and cytotoxic DNA lesions such as non-bulky base modifications, abasic sites, and a range of chemically distinct single-strand breaks. Defects in BER have been linked to cancer predisposition, neurodegenerative disorders, and immunodeficiency. Recent data indicate a large degree of sequence variability in DNA repair genes and several studies have associated BER gene polymorphisms with disease risk, including cancer of several sites. The intent of this review is to describe the range of BER capacity among individuals and the functional consequences of BER genetic variants. We also discuss studies that associate BER deficiency with disease risk and the current state of BER capacity measurement assays. PMID:21167187

  13. DNA repair and radiation sensitivity in mammalian cells

    SciTech Connect

    Chen, D.J.C.; Stackhouse, M.; Chen, D.S.

    1993-02-01

    Ionizing radiation induces various types of damage in mammalian cells including DNA single-strand breaks, DNA double-strand breaks (DSB), DNA-protein cross links, and altered DNA bases. Although human cells can repair many of these lesions there is little detailed knowledge of the nature of the genes and the encoded enzymes that control these repair processes. We report here on the cellular and genetic analyses of DNA double-strand break repair deficient mammalian cells. It has been well established that the DNA double-strand break is one of the major lesions induced by ionizing radiation. Utilizing rodent repair-deficient mutant, we have shown that the genes responsible for DNA double-strand break repair are also responsible for the cellular expression of radiation sensitivity. The molecular genetic analysis of DSB repair in rodent/human hybrid cells indicate that at least 6 different genes in mammalian cells are responsible for the repair of radiation-induced DNA double-strand breaks. Mapping and the prospect of cloning of human radiation repair genes are reviewed. Understanding the molecular and genetic basis of radiation sensitivity and DNA repair in man will provide a rational foundation to predict the individual risk associated with radiation exposure and to prevent radiation-induced genetic damage in the human population.

  14. DNA repair and radiation sensitivity in mammalian cells

    SciTech Connect

    Chen, D.J.C.; Stackhouse, M. ); Chen, D.S. . Dept. of Radiation Oncology)

    1993-01-01

    Ionizing radiation induces various types of damage in mammalian cells including DNA single-strand breaks, DNA double-strand breaks (DSB), DNA-protein cross links, and altered DNA bases. Although human cells can repair many of these lesions there is little detailed knowledge of the nature of the genes and the encoded enzymes that control these repair processes. We report here on the cellular and genetic analyses of DNA double-strand break repair deficient mammalian cells. It has been well established that the DNA double-strand break is one of the major lesions induced by ionizing radiation. Utilizing rodent repair-deficient mutant, we have shown that the genes responsible for DNA double-strand break repair are also responsible for the cellular expression of radiation sensitivity. The molecular genetic analysis of DSB repair in rodent/human hybrid cells indicate that at least 6 different genes in mammalian cells are responsible for the repair of radiation-induced DNA double-strand breaks. Mapping and the prospect of cloning of human radiation repair genes are reviewed. Understanding the molecular and genetic basis of radiation sensitivity and DNA repair in man will provide a rational foundation to predict the individual risk associated with radiation exposure and to prevent radiation-induced genetic damage in the human population.

  15. Methods to study transcription-coupled repair in chromatin.

    PubMed

    Gaillard, Hélène; Wellinger, Ralf Erik; Aguilera, Andrés

    2015-01-01

    The effect of endogenous and exogenous DNA damage on the cellular metabolism can be studied at the genetic and molecular level. A paradigmatic case is the repair of UV-induced pyrimidine dimers (PDs) by nucleotide excision repair (NER) in Saccharomyces cerevisiae. To follow the formation and repair of PDs at specific chromosome loci, cells are irradiated with UV-light and incubated in the dark to allow repair by NER. Upon DNA isolation, cyclobutane pyrimidine dimers, which account for about 90 % of PDs, can be cleaved in vitro by the DNA nicking activity of the T4 endonuclease V repair enzyme. Subsequently, strand-specific repair in a suitable restriction fragment is determined by denaturing gel electrophoresis followed by Southern blot and indirect end-labeling using a single-stranded DNA probe. Noteworthy, this protocol could potentially be adapted to other kind of DNA lesions, as long as a DNA nick is formed or a lesion-specific endonuclease is available.Transcription-coupled repair (TC-NER) is a sub-pathway of NER that catalyzes the repair of the transcribed strand of active genes. RNA polymerase II is essential for TC-NER, and its occupancy on a damaged template can be analyzed by chromatin immunoprecipitation (ChIP). In this chapter, we provide an up-dated protocol for both the DNA repair analysis and ChIP approaches to study TC-NER in yeast chromatin. PMID:25827885

  16. Chromatin modifications and DNA repair: beyond double-strand breaks

    PubMed Central

    House, Nealia C. M.; Koch, Melissa R.; Freudenreich, Catherine H.

    2014-01-01

    DNA repair must take place in the context of chromatin, and chromatin modifications and DNA repair are intimately linked. The study of double-strand break repair has revealed numerous histone modifications that occur after induction of a DSB, and modification of the repair factors themselves can also occur. In some cases the function of the modification is at least partially understood, but in many cases it is not yet clear. Although DSB repair is a crucial activity for cell survival, DSBs account for only a small percentage of the DNA lesions that occur over the lifetime of a cell. Repair of single-strand gaps, nicks, stalled forks, alternative DNA structures, and base lesions must also occur in a chromatin context. There is increasing evidence that these repair pathways are also regulated by histone modifications and chromatin remodeling. In this review, we will summarize the current state of knowledge of chromatin modifications that occur during non-DSB repair, highlighting similarities and differences to DSB repair as well as remaining questions. PMID:25250043

  17. Repair of DNA Double-Strand Breaks

    NASA Astrophysics Data System (ADS)

    Falk, Martin; Lukasova, Emilie; Kozubek, Stanislav

    The genetic information of cells continuously undergoes damage induced by intracellular processes including energy metabolism, DNA replication and transcription, and by environmental factors such as mutagenic chemicals and UV and ionizing radiation. This causes numerous DNA lesions, including double strand breaks (DSBs). Since cells cannot escape this damage or normally function with a damaged genome, several DNA repair mechanisms have evolved. Although most "single-stranded" DNA lesions are rapidly removed from DNA without permanent damage, DSBs completely break the DNA molecule, presenting a real challenge for repair mechanisms, with the highest risk among DNA lesions of incorrect repair. Hence, DSBs can have serious consequences for human health. Therefore, in this chapter, we will refer only to this type of DNA damage. In addition to the biochemical aspects of DSB repair, which have been extensively studied over a long period of time, the spatio-temporal organization of DSB induction and repair, the importance of which was recognized only recently, will be considered in terms of current knowledge and remaining questions.

  18. DNA repair responses in human skin cells

    SciTech Connect

    Hanawalt, P.C.; Liu, S.C.; Parsons, C.S.

    1981-07-01

    Sunlight and some environmental chemical agents produce lesions in the DNA of human skin cells that if unrepaired may interfere with normal functioning of these cells. The most serious outcome of such interactions may be malignancy. It is therefore important to develop an understanding of mechanisms by which the lesions may be repaired or tolerated without deleterious consequences. Our models for the molecular processing of damaged DNA have been derived largely from the study of bacterial systems. Some similarities but significant differences are revealed when human cell responses are tested against these models. It is also of importance to learn DNA repair responses of epidermal keratinocytes for comparison with the more extensive studies that have been carried out with dermal fibroblasts. Our experimental results thus far indicate similarities for the excision-repair of ultraviolet-induced pyrimidine dimers in human keratinocytes and fibroblasts. Both the monoadducts and the interstrand crosslinks produced in DNA by photoactivated 8-methoxypsoralen (PUVA) can be repaired in normal human fibroblasts but not in those from xeroderma pigmentosum patients. The monoadducts, like pyrimidine dimers, are probably the more mutagenic/carcinogenic lesions while the crosslinks are less easily repaired and probably result in more effective blocking of DNA function. It is suggested that a split-dose protocol that maximizes the production of crosslinks while minimizing the yield of monoadducts may be more effective and potentially less carcinogenic than the single ultraviolet exposure regimen in PUVA therapy for psoriasis.

  19. SLAP Repairs With Combined Procedures Have Lower Failure Rate Than Isolated Repairs in a Military Population

    PubMed Central

    Waterman, Brian R.; Arroyo, William; Heida, Kenneth; Burks, Robert; Pallis, Mark

    2015-01-01

    Background: Injuries to the superior glenoid labrum represent a significant cause of shoulder pain among active patients. The physical requirements of military service may contribute to an increased risk of injury. Limited data are available regarding the success of superior labral anterior posterior (SLAP) repairs in an active military population. Purpose: To quantify the rate of clinical failure and surgical revision after isolated and combined SLAP repair. Study Design: Cohort study; Level of evidence, 3. Methods: All consecutive active-duty servicemembers undergoing arthroscopic repair of type II SLAP lesions at a single institution between 2006 and 2012 were identified. Patients with less than 2-year clinical follow-up and nonmilitary status were excluded. Demographic variables, surgical variables, and occupational outcomes were extracted from electronic medical records and confirmed with the US Army Physical Disability Agency database. Failure was defined as subsequent revision surgery or medical discharge with persistent shoulder complaints. Results: A total of 192 patients with SLAP repair were identified with a mean follow-up of 50.0 months (SD, 17.0 months). Isolated SLAP repair occurred in 31.3% (n = 60) versus 68.8% (n = 132) with concomitant procedures. At final follow-up, 37.0% (n = 71) of patients reported some subjective activity-related shoulder pain. Postoperative return to duty occurred in 79.6% (n = 153), and only 20.3% (n = 39) were discharged with continuing shoulder disability. The combined rotator cuff repair (96%; P = .023) and anteroinferior labral repair group (88%; P = .056) had a higher rate of functional return than isolated SLAP repair (70%). Thirty-one (16.1%) patients were classified as surgical failure and required revision. Of these, the majority of patients undergoing biceps tenodesis (76%) returned to active duty, as compared with revision SLAP repair (17%). Lower demand occupation and the presence of combined shoulder injuries

  20. Double mutants of Saccharomyces cerevisiae with alterations in global genome and transcription-coupled repair.

    PubMed Central

    Verhage, R A; van Gool, A J; de Groot, N; Hoeijmakers, J H; van de Putte, P; Brouwer, J

    1996-01-01

    The nucleotide excision repair (NER) pathway is thought to consist of two subpathways: transcription-coupled repair, limited to the transcribed strand of active genes, and global genome repair for nontranscribed DNA strands. Recently we cloned the RAD26 gene, the Saccharomyces cerevisiae homolog of human CSB/ERCC6, a gene involved in transcription-coupled repair and the disorder Cockayne syndrome. This paper describes the analysis of yeast double mutants selectively affected in each NER subpathway. Although rad26 disruption mutants are defective in transcription-coupled repair, they are not UV sensitive. However, double mutants of RAD26 with the global genome repair determinants RAD7 and RAD16 appeared more UV sensitive than the single rad7 or rad16 mutants but not as sensitive as completely NER-deficient mutants. These findings unmask a role of RAD26 and transcription-coupled repair in UV survival, indicate that transcription-coupled repair and global genome repair are partially overlapping, and provide evidence for a residual NER modality in the double mutants. Analysis of dimer removal from the active RPB2 gene in the rad7/16 rad26 double mutants revealed (i) a contribution of the global genome repair factors Rad7p and Rad16p to repair of the transcribed strand, confirming the partial overlap between both NER subpathways, and (ii) residual repair specifically of the transcribed strand. To investigate the transcription dependence of this repair activity, strand-specific repair of the inducible GAL7 gene was investigated. The template strand of this gene was repaired only under induced conditions, pointing to a role for transcription in the residual repair in the double mutants and suggesting that transcription-coupled repair can to some extent operate independently from Rad26p. Our findings also indicate locus heterogeneity for the dependence of transcription-coupled repair on RAD26. PMID:8552076

  1. Rescheduling with iterative repair

    NASA Technical Reports Server (NTRS)

    Zweben, Monte; Davis, Eugene; Daun, Brian; Deale, Michael

    1992-01-01

    This paper presents a new approach to rescheduling called constraint-based iterative repair. This approach gives our system the ability to satisfy domain constraints, address optimization concerns, minimize perturbation to the original schedule, produce modified schedules, quickly, and exhibits 'anytime' behavior. The system begins with an initial, flawed schedule and then iteratively repairs constraint violations until a conflict-free schedule is produced. In an empirical demonstration, we vary the importance of minimizing perturbation and report how fast the system is able to resolve conflicts in a given time bound. We also show the anytime characteristics of the system. These experiments were performed within the domain of Space Shuttle ground processing.

  2. Laparoscopic repair for vesicouterine fistulae

    PubMed Central

    Maioli, Rafael A.; Macedo, André R. S.; Garcia, André R. L.; de Almeida, Silvio H. M.; Rodrigues, Marco Aurélio Freitas

    2015-01-01

    ABSTRACT Objective: The purpose of this video is to present the laparoscopic repair of a VUF in a 42-year-old woman, with gross hematuria, in the immediate postoperative phase following a cesarean delivery. The obstetric team implemented conservative management, including Foley catheter insertion, for 2 weeks. She subsequently developed intermittent hematuria and cystitis. The urology team was consulted 15 days after cesarean delivery. Cystoscopy indicated an ulcerated lesion in the bladder dome of approximately 1.0cm in size. Hysterosalpingography and a pelvic computed tomography scan indicated a fistula. Materials and Methods: Laparoscopic repair was performed 30 days after the cesarean delivery. The patient was placed in the lithotomy position while also in an extreme Trendelenburg position. Pneumoperitoneum was established using a Veress needle in the midline infra-umbilical region, and a primary 11-mm port was inserted. Another 11-mm port was inserted exactly between the left superior iliac spine and the umbilicus. Two other 5-mm ports were established under laparoscopic guidance in the iliac fossa on both sides. The omental adhesions in the pelvis were carefully released and the peritoneum between the bladder and uterus was incised via cautery. Limited cystotomy was performed, and the specific sites of the fistula and the ureteral meatus were identified; thereafter, the posterior bladder wall was adequately mobilized away from the uterus. The uterine rent was then closed using single 3/0Vicryl sutures and two-layer watertight closure of the urinary bladder was achieved by using 3/0Vicryl sutures. An omental flap was mobilized and inserted between the uterus and the urinary bladder, and was fixed using two 3/0Vicryl sutures, followed by tube drain insertion. Results: The operative time was 140 min, whereas the blood loss was 100ml. The patient was discharged 3 days after surgery, and the catheter was removed 12 days after surgery. Discussion: Laparoscopy has

  3. [ENDOVASCULAR ABDOMINAL AORTIC ANEURISM REPAIR].

    PubMed

    Maĭstrenko, D N; Generalov, M I; Tarazov, P G; Zherebtsov, F K; Osovskikh, V V; Ivanov, A S; Oleshchuk, A N; Granov, D A

    2015-01-01

    The authors analyzed the single-center experience of treatment of 72 patients with abdominal aortic aneurisms and severe accompanied pathology. The aneurisms were repaired by stent-grafts. All the patients had abdominal aortic aneurisms with the diameters from 41 to 84 mm against the background of severe somatic pathology. It was a contraindication to planned open surgery. An installation of stent-graft was successful in all 72 follow-ups. It wasn't necessary to use a conversion to open surgery. The follow-up period consisted of 44,6?2,1 months. Control ultrasound and computer tomography studies hadn't revealed an increase of aneurism sack sizes or "eakages". A reduction of abdominal aortic aneurism sizes was noted in 37 patients on 4-5% during first year after operation. The stent-graft implantation extends the possibilities of abdominal aortic aneurism treatment for patients from a high surgical risk group. PMID:26234059

  4. Heavy Metal Exposure Influences Double Strand Break DNA Repair Outcomes

    PubMed Central

    Morales, Maria E.; Derbes, Rebecca S.; Ade, Catherine M.; Ortego, Jonathan C.; Stark, Jeremy; Deininger, Prescott L.; Roy-Engel, Astrid M.

    2016-01-01

    Heavy metals such as cadmium, arsenic and nickel are classified as carcinogens. Although the precise mechanism of carcinogenesis is undefined, heavy metal exposure can contribute to genetic damage by inducing double strand breaks (DSBs) as well as inhibiting critical proteins from different DNA repair pathways. Here we take advantage of two previously published culture assay systems developed to address mechanistic aspects of DNA repair to evaluate the effects of heavy metal exposures on competing DNA repair outcomes. Our results demonstrate that exposure to heavy metals significantly alters how cells repair double strand breaks. The effects observed are both specific to the particular metal and dose dependent. Low doses of NiCl2 favored resolution of DSBs through homologous recombination (HR) and single strand annealing (SSA), which were inhibited by higher NiCl2 doses. In contrast, cells exposed to arsenic trioxide preferentially repaired using the “error prone” non-homologous end joining (alt-NHEJ) while inhibiting repair by HR. In addition, we determined that low doses of nickel and cadmium contributed to an increase in mutagenic recombination-mediated by Alu elements, the most numerous family of repetitive elements in humans. Sequence verification confirmed that the majority of the genetic deletions were the result of Alu-mediated non-allelic recombination events that predominantly arose from repair by SSA. All heavy metals showed a shift in the outcomes of alt-NHEJ repair with a significant increase of non-templated sequence insertions at the DSB repair site. Our data suggest that exposure to heavy metals will alter the choice of DNA repair pathway changing the genetic outcome of DSBs repair. PMID:26966913

  5. Bone fracture repair - series (image)

    MedlinePlus

    The three main treatment options for bone fractures are: Casting Open reduction, and internal fixation- this involves a surgery to repair the fracture-frequently, metal rods, screws or plates are used to repair the ...

  6. Cleft lip and palate repair

    MedlinePlus

    Orofacial cleft; Craniofacial birth defect repair; Cheiloplasty; Cleft rhinoplasty; Palatoplasty; Tip rhinoplasty ... these conditions at birth. Most times, cleft lip repair is done when the child is 6 to ...

  7. Electric motor model repair specifications

    SciTech Connect

    1995-08-01

    These model repair specifications list the minimum requirements for repair and overhaul of polyphase AC squireel cage induction motors. All power ranges, voltages, and speeds of squirrel cage motors are covered.

  8. Base excision repair: a critical player in many games.

    PubMed

    Wallace, Susan S

    2014-07-01

    This perspective reviews the many dimensions of base excision repair from a 10,000 foot vantage point and provides one person's view on where the field is headed. Enzyme function is considered under the lens of X-ray diffraction and single molecule studies. Base excision repair in chromatin and telomeres, regulation of expression and the role of posttranslational modifications are also discussed in the context of enzyme activities, cellular localization and interacting partners. The specialized roles that base excision repair play in transcriptional activation by active demethylation and targeted oxidation as well as how base excision repair functions in the immune processes of somatic hypermutation and class switch recombination and its possible involvement in retroviral infection are also discussed. Finally the complexities of oxidative damage and its repair and its link to neurodegenerative disorders, as well as the role of base excision repair as a tumor suppressor are examined in the context of damage, repair and aging. By outlining the many base excision repair-related mysteries that have yet to be unraveled, hopefully this perspective will stimulate further interest in the field.

  9. Base excision repair: A critical player in many games

    PubMed Central

    Wallace, Susan S.

    2014-01-01

    This perspective reviews the many dimensions of base excision repair from a 10,000 foot vantage point and provides one person’s view on where the field is headed. Enzyme function is considered under the lens of X-ray diffraction and single molecule studies. Base excision repair in chromatin and telomeres, regulation of expression and the role of posttranslational modifications are also discussed in the context of enzyme activities, cellular localization and interacting partners. The specialized roles that base excision repair play in transcriptional activation by active demethylation and targeted oxidation as well as how base excision repair functions in the immune processes of somatic hypermutation and class switch recombination and its possible involvement in retroviral infection are also discussed. Finally the complexities of oxidative damage and its repair and its link to neurodegenerative disorders, as well as the role of base excision repair as a tumor suppressor are examined in the context of damage, repair and aging. By outlining the many base excision repair-related mysteries that have yet to be unraveled, hopefully this perspective will stimulate further interest in the field. PMID:24780558

  10. Repair of proboscis lateralis.

    PubMed

    Uğurlu, Kemal; Karşidag, Semra; Ozçelik, Derya; Sadikoğlu, Buğra; Baş, Lütfü

    2005-01-01

    We report an 8-year-old girl presented with a proboscis on the right nasal nostril, right heminasal hypoplasia, hypertelorism, and cleft lip and palate on the other side. After repair of the cleft lip and palate and the hypertelorism, we successfully reconstructed the heminose with a V-Y advancement flap containing the proboscis tube. PMID:16019753

  11. Repairing cracked glass

    NASA Technical Reports Server (NTRS)

    Helman, D. D.; Holt, J. W.; Smiser, L. V.

    1979-01-01

    Filing procedure consisting of machined lightweight fused-silica tiles coated with thin-layer of borosilicate glass produces homogeneous seal in thin glass. Procedure is useful in repairing glass envelopes, X-ray tub windows, Dewar flasks, and similar thin glass objects.

  12. Automotive Body Repair Competencies.

    ERIC Educational Resources Information Center

    D'Armond, Jack; And Others

    Designed to provide a model curriculum and guidelines, this manual presents tasks that were identified by employers, employees, and teachers as important in a postsecondary auto body repair curriculum. The tasks are divided into ten major component areas of instruction: metalworking and fiberglass, painting, frame and suspension, glass and trim,…

  13. Patent urachus repair - slideshow

    MedlinePlus

    ... Drugs & Supplements Videos & Tools About MedlinePlus Show Search Search MedlinePlus GO GO About MedlinePlus Site Map FAQs Contact Us Health Topics Drugs & Supplements Videos & Tools Español You Are Here: Home → Medical Encyclopedia → Patent urachus repair - series—Normal anatomy URL of this ...

  14. Aircraft Propeller Hub Repair

    SciTech Connect

    Muth, Thomas R.; Peter, William H.

    2015-02-13

    The team performed a literature review, conducted residual stress measurements, performed failure analysis, and demonstrated a solid state additive manufacturing repair technique on samples removed from a scrapped propeller hub. The team evaluated multiple options for hub repair that included existing metal buildup technologies that the Federal Aviation Administration (FAA) has already embraced, such as cold spray, high velocity oxy-fuel deposition (HVOF), and plasma spray. In addition the team helped Piedmont Propulsion Systems, LLC (PPS) evaluate three potential solutions that could be deployed at different stages in the life cycle of aluminum alloy hubs, in addition to the conventional spray coating method for repair. For new hubs, a machining practice to prevent fretting with the steel drive shaft was recommended. For hubs that were refurbished with some material remaining above the minimal material condition (MMC), a silver interface applied by an electromagnetic pulse additive manufacturing method was recommended. For hubs that were at or below the MMC, a solid state additive manufacturing technique using ultrasonic welding (UW) of thin layers of 7075 aluminum to the hub interface was recommended. A cladding demonstration using the UW technique achieved mechanical bonding of the layers showing promise as a viable repair method.

  15. Basic Book Repair Methods.

    ERIC Educational Resources Information Center

    Schechter, Abraham A.

    This book addresses some common preservation techniques that invariably become necessary in library and archival collections of any size. The procedures are described in chronological sequence, and photographs show the techniques from the viewpoint of the person actually doing the work. The recommended repair methods can be accomplished using…

  16. Comprehensive Small Engine Repair.

    ERIC Educational Resources Information Center

    Hires, Bill; And Others

    This curriculum guide contains the basic information needed to repair all two- and four-stroke cycle engines. The curriculum covers four areas, each consisting of one or more units of instruction that include performance objectives, suggested activities for teacher and students, information sheets, assignment sheets, job sheets, visual aids,…

  17. Targeting Nuclear Envelope Repair.

    PubMed

    2016-06-01

    Migrating cancer cells undergo repeated rupture of the protective nuclear envelope as they squeeze through small spaces in the surrounding tissue, compromising genomic integrity. Inhibiting both general DNA repair and the mechanism that seals these tears may enhance cell death and curb metastasis. PMID:27130435

  18. Repairing Holes in Pressure Walls

    NASA Technical Reports Server (NTRS)

    Mori, Paul Bruce Y.; Capriloa, Laurie J.; Corocado, Alexander R.; Gibbins, Martin N.; Horne, Robert B.

    1987-01-01

    Patches and easy-to-use tools yield pressure-tight seal. Repairer lifts patch from repair kit with hook-and-pile-tipped tool and positions it over puncture hole. With tool, even gloved repairer easily manipulates patch without damaging it.

  19. Lawn and Garden Equipment Repair.

    ERIC Educational Resources Information Center

    Hardway, Jack; And Others

    This publication is designed to supplement the Comprehensive Small Engine Rapair guide by covering in detail all aspects of lawn and garden equipment repair not included in general engine repair or the repair of other small engines. It consists of instructional materials for both teachers and students, written in terms of student performance using…

  20. Cleft lip repair - series (image)

    MedlinePlus

    ... the middle of the upper lip. A cleft palate is an opening in the roof of the mouth (palate). ... Cleft lip repair and cleft palate repair are indicated for: Repair of physical deformity Nursing, feeding, or speech problems resulting from cleft lip or palate

  1. Automotive Engine Maintenance and Repair.

    ERIC Educational Resources Information Center

    Marine Corps Inst., Washington, DC.

    This correspondence course, originally developed for the Marine Corps, is designed to provide students with an understanding of automotive engine maintenance and repair. The course contains six study units covering automotive engine maintenance and repair; design classification; engine malfunction, diagnosis, and repair; engine disassembly; engine…

  2. A comparison of balloon angioplasty of native coarctation versus surgical repair for short segment coarctation associated with ventricular septal defect—a single-center retrospective review of 92 cases

    PubMed Central

    Zhang, Huifeng; Ye, Ming; Chen, Gang; Liu, Fang; Wu, Lin

    2016-01-01

    Background The hybrid technique combining balloon angioplasty for discrete coarctation (CoA) and surgical repair of a ventricular septal defect (VSD) is a novel treatment for patients with aortic CoA and VSD, but the efficacy of this approach is unknown. Methods We performed a retrospective analysis of 92 patients with short segment CoA and VSD who underwent complete repair between January 2004 and July 2014 in our center. Patients were divided into two groups according to the surgical approach employed: hybrid procedure (group A, n=39) and traditional midline surgical repair (group B, n=53). Baseline, perioperative, and outcome data were compared between the two groups. Results Three early deaths occurred in group B, whereas none occurred in group A. Compared to those in group B, patients in group A experienced a shorter aortic clamp duration (28.1±6.7 vs. 43.2±9.2 minutes, P<0.001), shorter cardiopulmonary bypass (CPB) duration (52.9±10.7 vs. 86.2±23.8 minutes, P<0.001), shorter ventilator time (47.0 vs. 73.7 hours, P=0.002), and shorter intensive care unit stay (6.2 vs. 9.1 days, P=0.019). The risks for aortic re-CoA and re-intervention did not differ significantly between the groups within five years (P=0.40 and 0.65, respectively). Conclusions The hybrid technique was associated with better periprocedural outcomes for patients with short-segment CoA and VSD. The incidences of aortic re-CoA and re-intervention were comparable between the hybrid technique and surgical groups over a mid-term follow-up.

  3. A comparison of balloon angioplasty of native coarctation versus surgical repair for short segment coarctation associated with ventricular septal defect—a single-center retrospective review of 92 cases

    PubMed Central

    Zhang, Huifeng; Ye, Ming; Chen, Gang; Liu, Fang; Wu, Lin

    2016-01-01

    Background The hybrid technique combining balloon angioplasty for discrete coarctation (CoA) and surgical repair of a ventricular septal defect (VSD) is a novel treatment for patients with aortic CoA and VSD, but the efficacy of this approach is unknown. Methods We performed a retrospective analysis of 92 patients with short segment CoA and VSD who underwent complete repair between January 2004 and July 2014 in our center. Patients were divided into two groups according to the surgical approach employed: hybrid procedure (group A, n=39) and traditional midline surgical repair (group B, n=53). Baseline, perioperative, and outcome data were compared between the two groups. Results Three early deaths occurred in group B, whereas none occurred in group A. Compared to those in group B, patients in group A experienced a shorter aortic clamp duration (28.1±6.7 vs. 43.2±9.2 minutes, P<0.001), shorter cardiopulmonary bypass (CPB) duration (52.9±10.7 vs. 86.2±23.8 minutes, P<0.001), shorter ventilator time (47.0 vs. 73.7 hours, P=0.002), and shorter intensive care unit stay (6.2 vs. 9.1 days, P=0.019). The risks for aortic re-CoA and re-intervention did not differ significantly between the groups within five years (P=0.40 and 0.65, respectively). Conclusions The hybrid technique was associated with better periprocedural outcomes for patients with short-segment CoA and VSD. The incidences of aortic re-CoA and re-intervention were comparable between the hybrid technique and surgical groups over a mid-term follow-up. PMID:27621858

  4. Base Excision Repair and Cancer

    PubMed Central

    Wallace, Susan S.; Murphy, Drew L.; Sweasy, Joann B.

    2012-01-01

    Base excision repair is the system used from bacteria to man to remove the tens of thousands of endogenous DNA damages produced daily in each human cell. Base excision repair is required for normal mammalian development and defects have been associated with neurological disorders and cancer. In this paper we provide an overview of short patch base excision repair in humans and summarize current knowledge of defects in base excision repair in mouse models and functional studies on short patch base excision repair germ line polymorphisms and their relationship to cancer. The biallelic germ line mutations that result in MUTYH-associated colon cancer are also discussed. PMID:22252118

  5. Gene Therapy for Cartilage Repair

    PubMed Central

    Madry, Henning; Orth, Patrick; Cucchiarini, Magali

    2011-01-01

    The concept of using gene transfer strategies for cartilage repair originates from the idea of transferring genes encoding therapeutic factors into the repair tissue, resulting in a temporarily and spatially defined delivery of therapeutic molecules to sites of cartilage damage. This review focuses on the potential benefits of using gene therapy approaches for the repair of articular cartilage and meniscal fibrocartilage, including articular cartilage defects resulting from acute trauma, osteochondritis dissecans, osteonecrosis, and osteoarthritis. Possible applications for meniscal repair comprise meniscal lesions, meniscal sutures, and meniscal transplantation. Recent studies in both small and large animal models have demonstrated the applicability of gene-based approaches for cartilage repair. Chondrogenic pathways were stimulated in the repair tissue and in osteoarthritic cartilage using genes for polypeptide growth factors and transcription factors. Although encouraging data have been generated, a successful translation of gene therapy for cartilage repair will require an ongoing combined effort of orthopedic surgeons and of basic scientists. PMID:26069580

  6. Coordination of dual incision and repair synthesis in human nucleotide excision repair

    PubMed Central

    Staresincic, Lidija; Fagbemi, Adebanke F; Enzlin, Jacqueline H; Gourdin, Audrey M; Wijgers, Nils; Dunand-Sauthier, Isabelle; Giglia-Mari, Giuseppina; Clarkson, Stuart G; Vermeulen, Wim; Schärer, Orlando D

    2009-01-01

    Nucleotide excision repair (NER) requires the coordinated sequential assembly and actions of the involved proteins at sites of DNA damage. Following damage recognition, dual incision 5′ to the lesion by ERCC1-XPF and 3′ to the lesion by XPG leads to the removal of a lesion-containing oligonucleotide of about 30 nucleotides. The resulting single-stranded DNA (ssDNA) gap on the undamaged strand is filled in by DNA repair synthesis. Here, we have asked how dual incision and repair synthesis are coordinated in human cells to avoid the exposure of potentially harmful ssDNA intermediates. Using catalytically inactive mutants of ERCC1-XPF and XPG, we show that the 5′ incision by ERCC1-XPF precedes the 3′ incision by XPG and that the initiation of repair synthesis does not require the catalytic activity of XPG. We propose that a defined order of dual incision and repair synthesis exists in human cells in the form of a ‘cut-patch-cut-patch' mechanism. This mechanism may aid the smooth progression through the NER pathway and contribute to genome integrity. PMID:19279666

  7. Coordination of dual incision and repair synthesis in human nucleotide excision repair.

    PubMed

    Staresincic, Lidija; Fagbemi, Adebanke F; Enzlin, Jacqueline H; Gourdin, Audrey M; Wijgers, Nils; Dunand-Sauthier, Isabelle; Giglia-Mari, Giuseppina; Clarkson, Stuart G; Vermeulen, Wim; Schärer, Orlando D

    2009-04-22

    Nucleotide excision repair (NER) requires the coordinated sequential assembly and actions of the involved proteins at sites of DNA damage. Following damage recognition, dual incision 5' to the lesion by ERCC1-XPF and 3' to the lesion by XPG leads to the removal of a lesion-containing oligonucleotide of about 30 nucleotides. The resulting single-stranded DNA (ssDNA) gap on the undamaged strand is filled in by DNA repair synthesis. Here, we have asked how dual incision and repair synthesis are coordinated in human cells to avoid the exposure of potentially harmful ssDNA intermediates. Using catalytically inactive mutants of ERCC1-XPF and XPG, we show that the 5' incision by ERCC1-XPF precedes the 3' incision by XPG and that the initiation of repair synthesis does not require the catalytic activity of XPG. We propose that a defined order of dual incision and repair synthesis exists in human cells in the form of a 'cut-patch-cut-patch' mechanism. This mechanism may aid the smooth progression through the NER pathway and contribute to genome integrity. PMID:19279666

  8. DNA repair: Dynamic defenders against cancer and aging

    SciTech Connect

    Fuss, Jill O.; Cooper, Priscilla K.

    2006-04-01

    You probably weren't thinking about your body's cellular DNA repair systems the last time you sat on the beach in the bright sunshine. Fortunately, however, while you were subjecting your DNA to the harmful effects of ultraviolet light, your cells were busy repairing the damage. The idea that our genetic material could be damaged by the sun was not appreciated in the early days of molecular biology. When Watson and Crick discovered the structure of DNA in 1953 [1], it was assumed that DNA is fundamentally stable since it carries the blueprint of life. However, over 50 years of research have revealed that our DNA is under constant assault by sunlight, oxygen, radiation, various chemicals, and even our own cellular processes. Cleverly, evolution has provided our cells with a diverse set of tools to repair the damage that Mother Nature causes. DNA repair processes restore the normal nucleotide sequence and DNA structure of the genome after damage [2]. These responses are highly varied and exquisitely regulated. DNA repair mechanisms are traditionally characterized by the type of damage repaired. A large variety of chemical modifications can alter normal DNA bases and either lead to mutations or block transcription if not repaired, and three distinct pathways exist to remove base damage. Base excision repair (BER) corrects DNA base alterations that do not distort the overall structure of the DNA helix such as bases damaged by oxidation resulting from normal cellular metabolism. While BER removes single damaged bases, nucleotide excision repair (NER) removes short segments of nucleotides (called oligonucleotides) containing damaged bases. NER responds to any alteration that distorts the DNA helix and is the mechanism responsible for repairing bulky base damage caused by carcinogenic chemicals such as benzo [a]pyrene (found in cigarette smoke and automobile exhaust) as well as covalent linkages between adjacent pyrimidine bases resulting from the ultraviolet (UV

  9. DNA repair activity in fish and interest in ecotoxicology: a review.

    PubMed

    Kienzler, Aude; Bony, Sylvie; Devaux, Alain

    2013-06-15

    The knowledge of DNA repair in a target species is of first importance as it is the primary line of defense against genotoxicants, and a better knowledge of DNA repair capacity in fish could help to interpret genotoxicity data and/or assist in the choice of target species, developmental stage and tissues to focus on, both for environmental biomonitoring studies and DNA repair testing. This review focuses in a first part on what is presently known on a mechanistic basis, about the various DNA repair systems in fish, in vivo and in established cell lines. Data on base excision repair (BER), direct reversal with O⁶-alkylguanine transferase and double strand breaks repair, although rather scarce, are being reviewed, as well as nucleotide excision repair (NER) and photoreactivation repair (PER), which are by far the most studied repair mechanisms in fish. Most of these repair mechanisms seem to be strongly species and tissue dependent; they also depend on the developmental stage of the organisms. BER is efficient in vivo, although no data has been found on in vitro models. NER activity is quite low or even inexistent depending on the studies; however this lack is partly compensated by a strong PER activity, especially in early developmental stage. In a second part, a survey of the ecotoxicological studies integrating DNA repair as a parameter responding to single or mixture of contaminant is realized. Three main approaches are being used: the measurement of DNA repair gene expression after exposure, although it has not yet been clearly established whether gene expression is indicative of repair capacity; the monitoring of DNA damage removal by following DNA repair kinetics; and the modulation of DNA repair activity following exposure in situ, in order to assess the impact of exposure history on DNA repair capacity. Since all DNA repair processes are possible targets for environmental pollutants, we can also wonder at which extent such a modulation of repair capacities

  10. A biomechanical study of pediatric flexor profundus tendon repair

    PubMed Central

    Al-Thunayan, Turki A.; Al-Zahrani, Mohammed T.; Hakeem, Ahmad A.; Al-Zahrani, Fahad M.; Al-Qattan, Mohammad M.

    2016-01-01

    Objectives: To investigate the tensile strength of repaired flexor profundus tendons in young lambs, which would be equivalent to repairs in children older than 2 years of age. Methods: A comparative in-vitro experimental study conducted at King Saud University, Riyadh, Kingdom of Saudi Arabia from October 2014 to December 2015. We utilized 30 flexor profundus tendons of young lambs with a width of 4 mm. All tendons were repaired with a 4-strand repair technique using 4/0 polypropylene core sutures. In group I (n=10 tendons), 2 separate figure-of-eight sutures were applied. In group II (n=10 tendons), simple locking sutures were added to the corners of 2 separate figure-of-eight sutures. In group III (n=10 tendons), the locked cruciate repair was used. All tendon repairs were tested to single-cycle tensile failure. Results: There was no significant difference between groups II and III with regards to gap and breaking forces; and all forces of these 2 groups were significantly higher than the forces in group I. Conclusion: It was concluded that 4 mm-wide pediatric flexor tendons allow a 4-strand repair and the use of 4/0 sutures. The use of locking sutures increases the tensile strength to values that may allow protective mobilization in children. PMID:27570850

  11. Single Nucleotide Polymorphisms (SNPs) of RAD51-G172T and XRCC2-41657C/T Homologous Recombination Repair Genes and the Risk of Triple- Negative Breast Cancer in Polish Women.

    PubMed

    Michalska, Magdalena M; Samulak, Dariusz; Romanowicz, Hanna; Smolarz, Beata

    2015-09-01

    Double strand DNA breaks are the most dangerous DNA damage which, if non-repaired or misrepaired, may result in genomic instability, cancer transformation or cell death. RAD51 and XRCC2 encode proteins that are important for the repair of double-strand DNA breaks by homologous recombination. Therefore, genetic variability in these genes may contribute to the occurrence and progression of triple-negative breast cancer. The polymorphisms of the XRCC2 gene -41657C/T (rs718282) and of the RAD51 gene, -172G/T (rs1801321), were investigated by PCR-RFLP in 70 patients with triple-negative breast cancer and 70 age- and sex matched non-cancer controls. The obtained results demonstrated a significant positive association between the RAD51 T/T genotype and TNBC, with an adjusted odds ratio (OR) of 4.94 (p = 0.001). The homozygous T/T genotype was found in 60 % of TNBC cases and in 14 % of the used controls. Variant 172 T allele of RAD51 increased cancer risk (OR = 2.81 (1.72-4.58), p < .0001). No significant associations were observed between -41657C/T genotype of XRCC2 and the incidence of TNBC. There were no significant differences between the distribution of XRCC2 -41657C/T genotypes in the subgroups assigned to histological grades. The obtained results indicate that the polymorphism of RAD51, but not of XRCC2 gene, may be positively associated with the incidence of triple-negative breast carcinoma in the population of Polish women.

  12. Contemporary Concepts for the Bilateral Cleft Lip and Nasal Repair

    PubMed Central

    Khosla, Rohit K.; McGregor, Jyoti; Kelley, Patrick K.; Gruss, Joseph S.

    2012-01-01

    The bilateral cleft lip and nasal deformity presents a complex challenge for repair. Surgical techniques continue to evolve and are focused on primary anatomic realignment of the tissues. This can be accomplished in a single-stage or two-stage repair early in infancy to provide a foundation for future growth of the lip and nasal tissue. Most cleft surgeons currently perform a single-stage repair for simplifying patient care. Certain institutions utilize presurgical orthopedics for alignment of the maxillary segments and nasal shaping. Methods for the bilateral cleft lip repair are combined with various open and closed rhinoplasty techniques to achieve improved correction of the primary nasal deformity. There is recent focus on shaping the nose for columellar and tip support, as well as alar contour and alar base position. The authors will present a new technique for closure of the nasal floor to prevent the alveolar cleft fistula. Although the alveolar fistula is closed, alveolar bone grafting is still required at the usual time in dental development to fuse the maxilla. It is paramount to try and minimize the stigmata of secondary deformities that historically have been characteristic of the repaired bilateral cleft lip. A properly planned and executed repair reduces the number of revisions and can spare a child from living with secondary deformities. PMID:24179448

  13. The repair of sub-lethal damage and the stimulated repair of potentially lethal damage in Saintpaulia.

    PubMed

    Leenhouts, H P; Sijsma, M J; Litwiniszyn, M; Chadwick, K H

    1981-10-01

    The repair of sublethal and potentially lethal damage in stationary resting epidermal cells of Saintpaulia has been investigated. Fractionation experiments reveal an efficient repair of sublethal damage with a half-life of 1.9 hours. No repair of potentially lethal damage was noted when cultivation of the leaves was delayed for 24 hours after irradiation. At delay times of 2, 3 and 4 days some repair of potentially lethal damage has been found. A small pre-dose given 24 hours before a challenging dose improved the cells' chance to regenerate and the improvement has been shown to be compatible with an improved repair of potentially lethal damage induced by X-rays and fast neutrons. It hs been shown that the stimulated repair process takes 12 to 24 hours to develop, is dependent on the size of the pre-dose, has single-hit dose kinetics, and an r.b.e. of 1 for neutrons. With delayed cultivation of 2 days the stimulated repair process leads to an alteration in the shape of the regeneration (survival)-dose relationship which increases the low dose r.b.e. for neutrons from 10 to 35. PMID:6975252

  14. DNA repair in cultured keratinocytes.

    PubMed

    Liu, S C; Parsons, S; Hanawalt, P C

    1983-07-01

    Most of our understanding of DNA repair mechanisms in human cells has come from the study of these processes in cultured fibroblasts. The unique properties of keratinocytes and their pattern of terminal differentiation led us to a comparative examination of their DNA repair properties. We have examined the relative repair capabilities of the basal cells and the differentiated epidermal keratinocytes as well as possible correlations of DNA repair capacity with respect to age of the donor. In addition, since portions of human skin are chronically exposed to sunlight, we have assessed the repair response to ultraviolet (UV) irradiation (254 nm) when the cells are conditioned by chronic low-level UV irradiation. The methods of Liu and Karasek were used to grow pure keratinocytes on collagen gels following their isolation from abdominal skin of newborns and adults at autopsy. Density labeling with 5-bromodeoxyuridine was used to resolve repair replication from the semiconservative mode. We found similar repair characteristics in human epidermal keratinocytes to those previously reported for cultured fibroblasts. However, the DNA repair response in basal cells was much greater than that in differentiated cells from the same skin preparation. Our comparative studies of DNA repair in keratinocytes from infant and aged donors have revealed no significant age-related differences for repair of UV-induced damage to DNA. Sublethal UV conditioning of cells from infant skin had no appreciable effect on either the repair or normal replication response to higher, challenge doses of UVL. However, such conditioning resulted in attenuated repair in keratinocytes from adult skin after UV doses above 25 J/m2. In addition, a surprising enhancement in replication was seen in conditioned cells from adult following challenge UV doses.

  15. Endovascular abdominal aortic aneurysm repair

    PubMed Central

    Norwood, M G A; Lloyd, G M; Bown, M J; Fishwick, G; London, N J; Sayers, R D

    2007-01-01

    The operative mortality following conventional abdominal aortic aneurysm (AAA) repair has not fallen significantly over the past two decades. Since its inception in 1991, endovascular aneurysm repair (EVAR) has provided an alternative to open AAA repair and perhaps an opportunity to improve operative mortality. Two recent large randomised trials have demonstrated the short and medium term benefit of EVAR over open AAA repair, although data on the long term efficacy of the technique are still lacking. This review aimed at providing an overview of EVAR and a discussion of the potential benefits and current limitations of the technique. PMID:17267674

  16. DNA repair in cultured keratinocytes

    SciTech Connect

    Liu, S.C.; Parsons, S.; Hanawalt, P.C.

    1983-07-01

    Most of our understanding of DNA repair mechanisms in human cells has come from the study of these processes in cultured fibroblasts. The unique properties of keratinocytes and their pattern of terminal differentiation led us to a comparative examination of their DNA repair properties. The relative repair capabilities of the basal cells and the differentiated epidermal keratinocytes as well as possible correlations of DNA repair capacity with respect to age of the donor have been examined. In addition, since portions of human skin are chronically exposed to sunlight, the repair response to ultraviolet (UV) irradiation (254 nm) when the cells are conditioned by chronic low-level UV irradiation has been assessed. The comparative studies of DNA repair in keratinocytes from infant and aged donors have revealed no significant age-related differences for repair of UV-induced damage to DNA. Sublethal UV conditioning of cells from infant skin had no appreciable effect on either the repair or normal replication response to higher, challenge doses of UVL. However, such conditioning resulted in attenuated repair in keratinocytes from adult skin after UV doses above 25 J/m2. In addition, a surprising enhancement in replication was seen in conditioned cells from adult following challenge UV doses.

  17. 49 CFR 193.2617 - Repairs.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 3 2010-10-01 2010-10-01 false Repairs. 193.2617 Section 193.2617 Transportation...: FEDERAL SAFETY STANDARDS Maintenance § 193.2617 Repairs. (a) Repair work on components must be performed... repaired. (b) For repairs made while a component is operating, each operator shall include in...

  18. Industrial motor repair in the United States

    SciTech Connect

    Schueler, V.; Leistner, P.; Douglass, J.

    1994-09-01

    This report characterizes the motor repair industry in the United States; summarizes current motor repair and testing practice; and identifies barriers to energy motor repair practice and recommends strategies for overcoming those barriers.

  19. Membrane Repair: Mechanisms and Pathophysiology

    PubMed Central

    Cooper, Sandra T.; McNeil, Paul L.

    2015-01-01

    Eukaryotic cells have been confronted throughout their evolution with potentially lethal plasma membrane injuries, including those caused by osmotic stress, by infection from bacterial toxins and parasites, and by mechanical and ischemic stress. The wounded cell can survive if a rapid repair response is mounted that restores boundary integrity. Calcium has been identified as the key trigger to activate an effective membrane repair response that utilizes exocytosis and endocytosis to repair a membrane tear, or remove a membrane pore. We here review what is known about the cellular and molecular mechanisms of membrane repair, with particular emphasis on the relevance of repair as it relates to disease pathologies. Collective evidence reveals membrane repair employs primitive yet robust molecular machinery, such as vesicle fusion and contractile rings, processes evolutionarily honed for simplicity and success. Yet to be fully understood is whether core membrane repair machinery exists in all cells, or whether evolutionary adaptation has resulted in multiple compensatory repair pathways that specialize in different tissues and cells within our body. PMID:26336031

  20. Cobbler's Technique for Iridodialysis Repair

    PubMed Central

    Pandav, Surinder Singh; Gupta, Parul Chawla; Singh, Rishi Raj; Das, Kalpita; Kaushik, Sushmita; Raj, Srishti; Ram, Jagat

    2016-01-01

    We describe a novel “Cobbler's technique” for iridodialysis repair in the right eye of a patient aged 18 years, with a traumatic iridodialysis secondary to open globe injury with an iron rod. Our technique is simple with easy surgical maneuvers, that is, effective for repairing iridodialysis. The “Cobbler's technique” allows a maximally functional and cosmetic result for iridodialysis. PMID:26957855

  1. Cobbler's Technique for Iridodialysis Repair.

    PubMed

    Pandav, Surinder Singh; Gupta, Parul Chawla; Singh, Rishi Raj; Das, Kalpita; Kaushik, Sushmita; Raj, Srishti; Ram, Jagat

    2016-01-01

    We describe a novel "Cobbler's technique" for iridodialysis repair in the right eye of a patient aged 18 years, with a traumatic iridodialysis secondary to open globe injury with an iron rod. Our technique is simple with easy surgical maneuvers, that is, effective for repairing iridodialysis. The "Cobbler's technique" allows a maximally functional and cosmetic result for iridodialysis. PMID:26957855

  2. Laparoscopic paracolostomy hernia mesh repair.

    PubMed

    Virzí, Giuseppe; Giuseppe, Virzí; Scaravilli, Francesco; Francesco, Scaravilli; Ragazzi, Salvatore; Salvatore, Ragazzi; Piazza, Diego; Diego, Piazza

    2007-12-01

    Paracolostomy hernia is a common occurrence, representing a late complication of stoma surgery. Different surgical techniques have been proposed to repair the wall defect, but the lowest recurrence rates are associated with the use of mesh. We present the case report of a patient in which laparoscopic paracolostomy hernia mesh repair has been successfully performed. PMID:18097321

  3. Major Appliance Repair. Teacher Edition.

    ERIC Educational Resources Information Center

    Smreker, Eugene; Calvert, King

    This module is a comprehensive text on basic appliance repair, designed to prepare students for entry-level jobs in this growing field. Ensuring a firm grounding in electrical knowledge, the module contains 13 instructional units that cover the following topics: (1) major appliance repair orientation; (2) safety and first aid; (3) fundamentals of…

  4. Instructional Guide for Autobody Repair.

    ERIC Educational Resources Information Center

    Virginia Polytechnic Inst. and State Univ., Blacksburg. Dept. of Education.

    The curriculum guide was developed to serve as a statewide model for Virginia auto body repair programs. The guide is designed to 1,080 hours of instruction in eleven blocks: orientation, introduction, welding and cutting, techniques of shaping metal, body filler and fiberglass repairs, body and frame, removing and replacing damaged parts, basic…

  5. Communication Repair and Response Classes

    ERIC Educational Resources Information Center

    Meadan, Hedda; Halle, James W.

    2004-01-01

    A communicative repair has been defined as the ability to persist in communication and to modify, repeat, or revise a signal when the initial communication attempt failed. From an operant perspective, initial communicative acts and communicative repairs can be considered members of a response class in which each response produces the same outcome.…

  6. Pipe inspection and repair system

    NASA Technical Reports Server (NTRS)

    Schempf, Hagen (Inventor); Mutschler, Edward (Inventor); Chemel, Brian (Inventor); Boehmke, Scott (Inventor); Crowley, William (Inventor)

    2004-01-01

    A multi-module pipe inspection and repair device. The device includes a base module, a camera module, a sensor module, an MFL module, a brush module, a patch set/test module, and a marker module. Each of the modules may be interconnected to construct one of an inspection device, a preparation device, a marking device, and a repair device.

  7. Designing ideal conduits for peripheral nerve repair

    PubMed Central

    de Ruiter, Godard C. W.; Malessy, Martijn J. A.; Yaszemski, Michael J.; Windebank, Anthony J.; Spinner, Robert J.

    2010-01-01

    Nerve tubes, guides, or conduits are a promising alternative for autologous nerve graft repair. The first biodegradable empty single lumen or hollow nerve tubes are currently available for clinical use and are being used mostly in the repair of small-diameter nerves with nerve defects of < 3 cm. These nerve tubes are made of different biomaterials using various fabrication techniques. As a result these tubes also differ in physical properties. In addition, several modifications to the common hollow nerve tube (for example, the addition of Schwann cells, growth factors, and internal frameworks) are being investigated that may increase the gap that can be bridged. This combination of chemical, physical, and biological factors has made the design of a nerve conduit into a complex process that demands close collaboration of bioengineers, neuroscientists, and peripheral nerve surgeons. In this article the authors discuss the different steps that are involved in the process of the design of an ideal nerve conduit for peripheral nerve repair. PMID:19435445

  8. Precise and high-throughput femtopulse laser mask repair of large defects

    NASA Astrophysics Data System (ADS)

    White, Roy; LeClaire, Jeff; Robinson, Tod; Dinsdale, Andrew; Bozak, Ron; Lee, David A.

    2006-10-01

    As mask complexity has increased and design rules continued to shrink, the manufacturing cost per mask has steadily increased as well. Studies also show that defects are the number one issue for mask yield. Smaller defects are typically addressed through process development, or through photomask repair. The occurrence of large defects often may only be further reduced through use of expensive clean room improvements, like SMIF handling systems. The impact of each large defect therefore increases while the feasibility in their repair decreases as they can span a large number of adjoining densely packed patterns. The presence of sub-resolution features such as scatter bars and the increasing use of embedded phase-shifting masks also complicates the timely repair of such defects. Existing mask repair techniques such as nanomachining, electron beam, or focused ion beam are challenged to produce high yield repairs on such large defects within a reasonable timeframe. Often very complex repairs may in fact take longer than a rewrite of the mask! Deep UV (DUV) femtosecond pulse laser mask repair provides a unique solution to this defect repair need. Methods and results are discussed for the process optimization for the removal of large (5μm) area repair on both Cr and MoSi absorber films on quartz. Additionally, high repair throughput results are shown for unknown contamination removal, and reproduction of >=1 μm complex unconnected patterns in a single repair run lasting a matter of minutes. Closed-loop CD feedback in-situ with the iterative repair process for such structures can readily result in an edge placement control within +/-15 nm. Prior iterative CD closed-loop repairs on specific structures have reliably yielded results within +/-10 nm, as confirmed by AIMS CD error, even after aggressive mask wet clean. The nanometer scale dimensional resolution and repeatability of such repairs is shown with the use of sub-pixel resolution automated pattern reconstruction

  9. Sources of DNA Double-Strand Breaks and Models of Recombinational DNA Repair

    PubMed Central

    Mehta, Anuja; Haber, James E.

    2014-01-01

    DNA is subject to many endogenous and exogenous insults that impair DNA replication and proper chromosome segregation. DNA double-strand breaks (DSBs) are one of the most toxic of these lesions and must be repaired to preserve chromosomal integrity. Eukaryotes are equipped with several different, but related, repair mechanisms involving homologous recombination, including single-strand annealing, gene conversion, and break-induced replication. In this review, we highlight the chief sources of DSBs and crucial requirements for each of these repair processes, as well as the methods to identify and study intermediate steps in DSB repair by homologous recombination. PMID:25104768

  10. Nucleosomes determine their own patch size in base excision repair.

    PubMed

    Meas, Rithy; Smerdon, Michael J

    2016-01-01

    Base excision repair (BER) processes non-helix distorting lesions (e.g., uracils and gaps) and is composed of two subpathways that differ in the number of nucleotides (nts) incorporated during the DNA synthesis step: short patch (SP) repair incorporates 1 nt and long patch (LP) repair incorporates 2-12 nts. This choice for either LP or SP repair has not been analyzed in the context of nucleosomes. Initial studies with uracil located in nucleosome core DNA showed a distinct DNA polymerase extension profile in cell-free extracts that specifically limits extension to 1 nt, suggesting a preference for SP BER. Therefore, we developed an assay to differentiate long and short repair patches in 'designed' nucleosomes containing a single-nucleotide gap at specific locations relative to the dyad center. Using cell-free extracts or purified enzymes, we found that DNA lesions in the nucleosome core are preferentially repaired by DNA polymerase β and there is a significant reduction in BER polymerase extension beyond 1 nt, creating a striking bias for incorporation of short patches into nucleosomal DNA. These results show that nucleosomes control the patch size used by BER. PMID:27265863

  11. DNA repair of oxidative DNA damage in human carcinogenesis

    PubMed Central

    Paz-Elizur, Tamar; Sevilya, Ziv; Leitner-Dagan, Yael; Elinger, Dalia; Roisman, Laila; Livneh, Zvi

    2008-01-01

    Efficient DNA repair mechanisms comprise a critical component in the protection against human cancer, as indicated by the high predisposition to cancer of individuals with germ-line mutations in DNA repair genes. This includes biallelic germ-line mutations in the MUYH gene, encoding a DNA glycosylase that is involved in the repair of oxidative DNA damage, which strongly predispose humans to a rare hereditary form of colorectal cancer. Extensive research efforts including biochemical, enzymological and genetic studies in model organisms established that the oxidative DNA lesion 8-oxoguanine is mutagenic, and that several DNA repair mechanisms operate to prevent its potentially mutagenic and carcinogenic outcome. Epidemiological studies on the association with sporadic cancers of single nucleotide polymorphisms in genes such as OGG1, involved in the repair of 8-oxoguanine yielded conflicting results, and suggest a minor effect at best. A new approach based on the functional analysis of DNA repair enzymatic activity showed that reduced activity of 8-oxoguanine DNA glycosylase (OGG) is a risk factor in lung and head and neck cancer. Moreover, the combination of smoking and low OGG activity was associated with a higher risk, suggesting a potential strategy for risk assessment and prevention of lung cancer, as well as other types of cancer. PMID:18374480

  12. Nucleosomes determine their own patch size in base excision repair

    PubMed Central

    Meas, Rithy; Smerdon, Michael J.

    2016-01-01

    Base excision repair (BER) processes non-helix distorting lesions (e.g., uracils and gaps) and is composed of two subpathways that differ in the number of nucleotides (nts) incorporated during the DNA synthesis step: short patch (SP) repair incorporates 1 nt and long patch (LP) repair incorporates 2–12 nts. This choice for either LP or SP repair has not been analyzed in the context of nucleosomes. Initial studies with uracil located in nucleosome core DNA showed a distinct DNA polymerase extension profile in cell-free extracts that specifically limits extension to 1 nt, suggesting a preference for SP BER. Therefore, we developed an assay to differentiate long and short repair patches in ‘designed’ nucleosomes containing a single-nucleotide gap at specific locations relative to the dyad center. Using cell-free extracts or purified enzymes, we found that DNA lesions in the nucleosome core are preferentially repaired by DNA polymerase β and there is a significant reduction in BER polymerase extension beyond 1 nt, creating a striking bias for incorporation of short patches into nucleosomal DNA. These results show that nucleosomes control the patch size used by BER. PMID:27265863

  13. Gly322Asp and Asn127Ser single nucleotide polymorphisms (SNPs) of hMSH2 mismatch repair gene and the risk of triple-negative breast cancer in Polish women.

    PubMed

    Smolarz, Beata; Makowska, Marianna; Samulak, Dariusz; Michalska, Magdalena M; Romanowicz, Hanna

    2015-03-01

    Triple-negative breast cancer (TNBC) is characterised by worse clinical outcome and poor prognosis. The alterations in the oncogenes and tumor suppressor genes as well as microsatellite instability (MSI) have been associated with breast cancer development. It is knowledge that the most common mechanism inducing MSI in many cancer is genomic rearrangements found in the hMSH2 (human MutS homolog 2) gene. In this report we genotyped two polymorphisms of hMSH2 DNA repair gene in 70 TNBC patients and 70 age-matched cancer-free women using RFLP-PCR. The following polymorphisms were studied: an A/G transition at 127 positions producing an Asn/Ser substitution at codon 127 (the Asn127Ser polymorphism, rs17217772) and a G/A transition at 1032 position resulting in a Gly/Asp change at codon 322 (the Gly322Asp polymorphism, rs4987188). We found an association between the hMSH2 Asp/Asp and Gly/Asp genotypes and TNBC occurence. Variant Asp allele of hMSH2 decreased cancer risk [odds ratio (OR) 0.11; 95 % confidence interval (CI) 0.05-0.21]. The risk of TNBC in the carriers of the Gly322Gly-Asn127Ser combined genotype was increased (OR 3.71; 95 % CI 1.36-10.10). However the risk of TNBC was not alter by polymorphism Asn127Ser of the hMSH2 gene. The Gly322Asp polymorphism of the hMSH2 gene may be linked with TNBC occurrence in Polish women.

  14. Wound repair in Pocillopora.

    PubMed

    Rodríguez-Villalobos, Jenny Carolina; Work, Thierry Martin; Calderon-Aguilera, Luis Eduardo

    2016-09-01

    Corals routinely lose tissue due to causes ranging from predation to disease. Tissue healing and regeneration are fundamental to the normal functioning of corals, yet we know little about this process. We described the microscopic morphology of wound repair in Pocillopora damicornis. Tissue was removed by airbrushing fragments from three healthy colonies, and these were monitored daily at the gross and microscopic level for 40days. Grossly, corals healed by Day 30, but repigmentation was not evident at the end of the study (40d). On histology, from Day 8 onwards, tissues at the lesion site were microscopically indistinguishable from adjacent normal tissues with evidence of zooxanthellae in gastrodermis. Inflammation was not evident. P. damicornis manifested a unique mode of regeneration involving projections of cell-covered mesoglea from the surface body wall that anastomosed to form gastrovascular canals. PMID:27397755

  15. Wound repair in Pocillopora

    USGS Publications Warehouse

    Rodríguez-Villalobos, Jenny Carolina; Work, Thierry M.; Calderon-Aguileraa, Luis Eduardo

    2016-01-01

    Corals routinely lose tissue due to causes ranging from predation to disease. Tissue healing and regeneration are fundamental to the normal functioning of corals, yet we know little about this process. We described the microscopic morphology of wound repair in Pocillopora damicornis. Tissue was removed by airbrushing fragments from three healthy colonies, and these were monitored daily at the gross and microscopic level for 40 days. Grossly, corals healed by Day 30, but repigmentation was not evident at the end of the study (40 d). On histology, from Day 8 onwards, tissues at the lesion site were microscopically indistinguishable from adjacent normal tissues with evidence of zooxanthellae in gastrodermis. Inflammation was not evident. P. damicornis manifested a unique mode of regeneration involving projections of cell-covered mesoglea from the surface body wall that anastomosed to form gastrovascular canals.

  16. Wound repair in Pocillopora.

    PubMed

    Rodríguez-Villalobos, Jenny Carolina; Work, Thierry Martin; Calderon-Aguilera, Luis Eduardo

    2016-09-01

    Corals routinely lose tissue due to causes ranging from predation to disease. Tissue healing and regeneration are fundamental to the normal functioning of corals, yet we know little about this process. We described the microscopic morphology of wound repair in Pocillopora damicornis. Tissue was removed by airbrushing fragments from three healthy colonies, and these were monitored daily at the gross and microscopic level for 40days. Grossly, corals healed by Day 30, but repigmentation was not evident at the end of the study (40d). On histology, from Day 8 onwards, tissues at the lesion site were microscopically indistinguishable from adjacent normal tissues with evidence of zooxanthellae in gastrodermis. Inflammation was not evident. P. damicornis manifested a unique mode of regeneration involving projections of cell-covered mesoglea from the surface body wall that anastomosed to form gastrovascular canals.

  17. Coal bunker repairs

    SciTech Connect

    Emmons, M.H.; Hoffman, M.G. )

    1992-01-01

    Detroit Edison's St. Clair Power Plant (STCPP) Units 1 through 4 are 1950's vintage fossil fueled units with an average capacity of 163 megawatt per unit. Each unit had identical 2190 ton bunkers. The Unit No. 1 bunker had been experiencing noticeable exterior deterioration at the lower level internal support system. An internal bunker inspection revealed large deflections in the network of beams supporting the bunker side walls. A complete collapse of the internal support beams was imminent. Failure of these beams would have transferred the coal pressure loads to the bunker skin and external stiffeners which were not capable of sustaining the load and were also showing signs of distress. This paper presents the temporary repair installed immediately after inspection, the redesign of the lower internal support system and construction procedures involved in bringing the bunker back into operating condition.

  18. TPS Inspection and Repair

    NASA Technical Reports Server (NTRS)

    Parazynski, Scott

    2012-01-01

    Dr. Scott Parazynski provided a retrospective on the EVA tools and procedures efforts NASA went through in the aftermath of Columbia for the Shuttle Thermal Protection System (TPS) inspection and repair. He describes his role as the lead astronaut on this effort, and covered all of the Neutral Buoyancy Lab (NBL), KC 135 (reduced gravity aircraft), Precision Air Bearing Floor (PABF), vacuum chamber and 1 G testing that was done in order to develop the tools and techniques that were flown. Parazynski also discusses how the EVA community worked together to resolve a huge safety issue, and how his work in the spacesuit was critical to overcoming a design limitation of the Space Shuttle.

  19. 46 CFR 272.24 - Subsidy repair summaries.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... either a single voyage or multiple voyages, and shall be filed not later than 120 days after: (1) The... maintenance expenditures for the period stated, and that the repair and maintenance items indicated as... either from the Operator's own ship stores or shoreside inventory, or by direct purchase for a...

  20. Non-homologous end joining repair in Xenopus egg extract

    PubMed Central

    Zhu, Songli; Peng, Aimin

    2016-01-01

    Non-homologous end joining (NHEJ) is a major DNA double-strand break (DSB) repair mechanism. We characterized here a series of plasmid-based DSB templates that were repaired in Xenopus egg extracts via the canonical, Ku-dependent NHEJ pathway. We showed that the template with compatible ends was efficiently repaired without end processing, in a manner that required the kinase activity of DNA-PKcs but not ATM. Moreover, non-compatible ends with blunt/3′-overhang, blunt/5′-overhang, and 3′-overhang/5′-overhang were predominantly repaired with fill-in and ligation without the removal of end nucleotides. In contrast, 3′-overhang/3′-overhang and 5′-overhang/5′-overhang templates were processed by resection of 3–5 bases and fill-in of 1–4 bases prior to end ligation. Therefore, the NHEJ machinery exhibited a strong preference for precise repair; the presence of neither non-compatible ends nor protruding single strand DNA sufficiently warranted the action of nucleases. ATM was required for the efficient repair of all non-compatible ends including those repaired without end processing by nucleases, suggesting its role beyond phosphorylation and regulation of Artemis. Finally, dephosphorylation of the 5′-overhang/3′-overhang template reduced the efficiency of DNA repair without increasing the risk of end resection, indicating that end protection via prompt end ligation is not the sole mechanism that suppresses the action of nucleases. PMID:27324260

  1. Identification of novel DNA repair proteins via primary sequence, secondary structure, and homology

    PubMed Central

    Brown, JB; Akutsu, Tatsuya

    2009-01-01

    Background DNA repair is the general term for the collection of critical mechanisms which repair many forms of DNA damage such as methylation or ionizing radiation. DNA repair has mainly been studied in experimental and clinical situations, and relatively few information-based approaches to new extracting DNA repair knowledge exist. As a first step, automatic detection of DNA repair proteins in genomes via informatics techniques is desirable; however, there are many forms of DNA repair and it is not a straightforward process to identify and classify repair proteins with a single optimal method. We perform a study of the ability of homology and machine learning-based methods to identify and classify DNA repair proteins, as well as scan vertebrate genomes for the presence of novel repair proteins. Combinations of primary sequence polypeptide frequency, secondary structure, and homology information are used as feature information for input to a Support Vector Machine (SVM). Results We identify that SVM techniques are capable of identifying portions of DNA repair protein datasets without admitting false positives; at low levels of false positive tolerance, homology can also identify and classify proteins with good performance. Secondary structure information provides improved performance compared to using primary structure alone. Furthermore, we observe that machine learning methods incorporating homology information perform best when data is filtered by some clustering technique. Analysis by applying these methodologies to the scanning of multiple vertebrate genomes confirms a positive correlation between the size of a genome and the number of DNA repair protein transcripts it is likely to contain, and simultaneously suggests that all organisms have a non-zero minimum number of repair genes. In addition, the scan result clusters several organisms' repair abilities in an evolutionarily consistent fashion. Analysis also identifies several functionally unconfirmed

  2. DNA repair in Chromobacterium violaceum.

    PubMed

    Duarte, Fábio Teixeira; Carvalho, Fabíola Marques de; Bezerra e Silva, Uaska; Scortecci, Kátia Castanho; Blaha, Carlos Alfredo Galindo; Agnez-Lima, Lucymara Fassarella; Batistuzzo de Medeiros, Silvia Regina

    2004-03-31

    Chromobacterium violaceum is a Gram-negative beta-proteobacterium that inhabits a variety of ecosystems in tropical and subtropical regions, including the water and banks of the Negro River in the Brazilian Amazon. This bacterium has been the subject of extensive study over the last three decades, due to its biotechnological properties, including the characteristic violacein pigment, which has antimicrobial and anti-tumoral activities. C. violaceum promotes the solubilization of gold in a mercury-free process, and has been used in the synthesis of homopolyesters suitable for the production of biodegradable polymers. The complete genome sequence of this organism has been completed by the Brazilian National Genome Project Consortium. The aim of our group was to study the DNA repair genes in this organism, due to their importance in the maintenance of genomic integrity. We identified DNA repair genes involved in different pathways in C. violaceum through a similarity search against known sequences deposited in databases. The phylogenetic analyses were done using programs of the PHILYP package. This analysis revealed various metabolic pathways, including photoreactivation, base excision repair, nucleotide excision repair, mismatch repair, recombinational repair, and the SOS system. The similarity between the C. violaceum sequences and those of Neisserie miningitidis and Ralstonia solanacearum was greater than that between the C. violaceum and Escherichia coli sequences. The peculiarities found in the C. violaceum genome were the absence of LexA, some horizontal transfer events and a large number of repair genes involved with alkyl and oxidative DNA damage.

  3. Endovascular repair or open repair for ruptured abdominal aortic aneurysm: a Cochrane systematic review

    PubMed Central

    Badger, S A; Harkin, D W; Blair, P H; Ellis, P K; Kee, F; Forster, R

    2016-01-01

    Objectives Emergency endovascular aneurysm repair (eEVAR) may improve outcomes for patients with ruptured abdominal aortic aneurysm (RAAA). The study aim was to compare the outcomes for eEVAR with conventional open surgical repair for the treatment of RAAA. Setting A systematic review of relevant publications was performed. Randomised controlled trials (RCTs) comparing eEVAR with open surgical repair for RAAA were included. Participants 3 RCTs were included, with a total of 761 patients with RAAA. Interventions Meta-analysis was performed with fixed-effects models with ORs and 95% CIs for dichotomous data and mean differences with 95% CIs for continuous data. Primary and secondary outcome measures Primary outcome was short-term mortality. Secondary outcome measures included aneurysm-specific and general complication rates, quality of life and economic analysis. Results Overall risk of bias was low. There was no difference between the 2 interventions on 30-day (or in-hospital) mortality, OR 0.91 (95% CI 0.67 to 1.22; p=0.52). 30-day complications included myocardial infarction, stroke, composite cardiac complications, renal complications, severe bowel ischaemia, spinal cord ischaemia, reoperation, amputation and respiratory failure. Reporting was incomplete, and no robust conclusion was drawn. For complication outcomes that did include at least 2 studies in the meta-analysis, there was no clear evidence to support a difference between eEVAR and open repair. Longer term outcomes and cost per patient were evaluated in only a single study, thus precluding definite conclusions. Conclusions Outcomes between eEVAR and open repair, specifically 30-day mortality, are similar. However, further high-quality trials are required, as the paucity of data currently limits the conclusions. PMID:26873043

  4. DNA repair in Mycoplasma gallisepticum

    PubMed Central

    2013-01-01

    Background DNA repair is essential for the maintenance of genome stability in all living beings. Genome size as well as the repertoire and abundance of DNA repair components may vary among prokaryotic species. The bacteria of the Mollicutes class feature a small genome size, absence of a cell wall, and a parasitic lifestyle. A small number of genes make Mollicutes a good model for a “minimal cell” concept. Results In this work we studied the DNA repair system of Mycoplasma gallisepticum on genomic, transcriptional, and proteomic levels. We detected 18 out of 22 members of the DNA repair system on a protein level. We found that abundance of the respective mRNAs is less than one per cell. We studied transcriptional response of DNA repair genes of M. gallisepticum at stress conditions including heat, osmotic, peroxide stresses, tetracycline and ciprofloxacin treatment, stationary phase and heat stress in stationary phase. Conclusions Based on comparative genomic study, we determined that the DNA repair system M. gallisepticum includes a sufficient set of proteins to provide a cell with functional nucleotide and base excision repair and mismatch repair. We identified SOS-response in M. gallisepticum on ciprofloxacin, which is a known SOS-inducer, tetracycline and heat stress in the absence of established regulators. Heat stress was found to be the strongest SOS-inducer. We found that upon transition to stationary phase of culture growth transcription of DNA repair genes decreases dramatically. Heat stress does not induce SOS-response in a stationary phase. PMID:24148612

  5. Arthroscopic Rotator Cuff Repair Using the Undersurface Technique

    PubMed Central

    Rubenis, Imants; Lam, Patrick H.; Murrell, George A.C.

    2015-01-01

    Background: Arthroscopic rotator cuff repair has traditionally been performed in the subacromial space from the bursal side of the tendon. The undersurface rotator cuff repair technique involves the arthroscope remaining in the glenohumeral joint, thus viewing the tendon from its undersurface during repair without a bursectomy or acromioplasty. Purpose: To compare the clinical and structural outcomes of undersurface rotator cuff repair with bursal-side repair. Study Design: Cohort study; Level of evidence, 3. Methods: A retrospective analysis of prospectively collected data was conducted on 2 cohorts of patients who had undergone arthroscopic rotator cuff repair with knotless suture anchors configured in a single-row formation using inverted mattress–style sutures from either the bursal side (n = 100) or undersurface (n = 165) of the supraspinatus tendon. Data were collected preoperatively, intraoperatively, and at 1 week, 6 weeks, 3 months, 6 months, and 2 years postoperatively. At each time point, patients completed a modified L’Insalata questionnaire to assess patient-ranked pain scores and were clinically examined using standardized tests. Ultrasound examination was performed at 6 months and 2 years to assess the integrity of the repair. Results: At 2 years postoperatively, patients in both cohorts had significantly less pain and less difficulty with overhead activities compared with preoperative levels (P < .001). The type of repair performed (bursal or undersurface) did not affect the ability to perform overhead activities at 2 years. At 2 years, both groups also had similar retear rates (21% for bursal side, 23% for undersurface). The mean operative time for the arthroscopic rotator cuff repair was 32 minutes when performed from the bursal side and 20 minutes when performed from the undersurface (P < .001). Conclusion: Arthroscopic rotator cuff repair, whether performed from the subacromial space or glenohumeral joint, resulted in decreased levels of

  6. Interplay between mismatch repair and chromatin assembly

    PubMed Central

    Schöpf, Barbara; Bregenhorn, Stephanie; Quivy, Jean-Pierre; Kadyrov, Farid A.; Almouzni, Genevieve; Jiricny, Josef

    2012-01-01

    Single strand nicks and gaps in DNA have been reported to increase the efficiency of nucleosome loading mediated by chromatin assembly factor 1 (CAF-1). However, on mismatch-containing substrates, these strand discontinuities are utilized by the mismatch repair (MMR) system as loading sites for exonuclease 1, at which degradation of the error-containing strand commences. Because packaging of DNA into chromatin might inhibit MMR, we were interested to learn whether chromatin assembly is differentially regulated on heteroduplex and homoduplex substrates. We now show that the presence of a mismatch in a nicked plasmid substrate delays nucleosome loading in human cell extracts. Our data also suggest that, once the mismatch is removed, repair of the single-stranded gap is accompanied by efficient nucleosome loading. We postulated that the balance between MMR and chromatin assembly might be governed by proliferating cell nuclear antigen (PCNA), the processivity factor of replicative DNA polymerases, which is loaded at DNA termini and which interacts with the MSH6 subunit of the mismatch recognition factor MutSα, as well as with CAF-1. We now show that this regulation might be more complex; MutSα and CAF-1 interact not only with PCNA, but also with each other. In vivo this interaction increases during S-phase and may be controlled by the phosphorylation status of the p150 subunit of CAF-1. PMID:22232658

  7. A Bionic Neural Link for peripheral nerve repair.

    PubMed

    Xu, Yong Ping; Yen, Shih-Cheng; Ng, Kian Ann; Liu, Xu; Tan, Ter Chyan

    2012-01-01

    Peripheral nerve injuries with large gaps and long nerve regrowth paths are difficult to repair using existing surgical techniques, due to nerve degeneration and muscle atrophy. This paper proposes a Bionic Neural Link (BNL) as an alternative way for peripheral nerve repair. The concept of the BNL is described, along with the hypothetical benefits. A prototype monolithic single channel BNL has been developed, which consists of 16 neural recording channels and one stimulation channel, and is implemented in a 0.35-µm CMOS technology. The BNL has been tested in in-vivo animal experiments. Full function of the BNL chip has been demonstrated.

  8. 40 CFR 63.1005 - Leak repair.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... successful repair of the leak. (3) Maximum instrument reading measured by Method 21 of 40 CFR part 60... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Leak repair. 63.1005 Section 63.1005... Standards for Equipment Leaks-Control Level 1 § 63.1005 Leak repair. (a) Leak repair schedule. The owner...

  9. 40 CFR 63.1024 - Leak repair.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... reading measured by Method 21 of 40 CFR part 60, appendix A at the time the leak is successfully repaired... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Leak repair. 63.1024 Section 63.1024... Standards for Equipment Leaks-Control Level 2 Standards § 63.1024 Leak repair. (a) Leak repair schedule....

  10. 40 CFR 63.1024 - Leak repair.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... reading measured by Method 21 of 40 CFR part 60, appendix A at the time the leak is successfully repaired... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Leak repair. 63.1024 Section 63.1024... Standards for Equipment Leaks-Control Level 2 Standards § 63.1024 Leak repair. (a) Leak repair schedule....

  11. 40 CFR 63.1005 - Leak repair.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... successful repair of the leak. (3) Maximum instrument reading measured by Method 21 of 40 CFR part 60... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Leak repair. 63.1005 Section 63.1005... Standards for Equipment Leaks-Control Level 1 § 63.1005 Leak repair. (a) Leak repair schedule. The owner...

  12. Mammalian DNA Repair. Final Report

    SciTech Connect

    2003-01-24

    The Gordon Research Conference (GRC) on Mammalian DNA Repair was held at Harbortown Resort, Ventura Beach, CA. Emphasis was placed on current unpublished research and discussion of the future target areas in this field.

  13. Wnt Signaling During Fracture Repair

    PubMed Central

    Secreto, Frank J.; Hoeppner, Luke H.; Westendorf, Jennifer J.

    2010-01-01

    Bone is one of the few tissues in the body with the capacity to regenerate and repair itself. In most cases, fractures are completely repaired in a relatively short period of time; however, in a small percentage of cases, healing never occurs and non-union is the result. Fracture repair and bone regeneration require the localized re-activation of signaling cascades that are crucial for skeletal development. The Wnt/β-catenin signaling pathway is one such developmental pathway whose role in bone formation and regeneration has been recently appreciated. During the last decade, much has learned about how Wnt pathways regulate bone mass. Small molecules and biologics aimed at this pathway are now being tested as potential new anabolic agents. Here we review recent data demonstrating that Wnt pathways are active during fracture repair and that increasing the activities of Wnt pathway components accelerates bone regeneration. PMID:19631031

  14. Nucleotide excision repair in humans.

    PubMed

    Spivak, Graciela

    2015-12-01

    The demonstration of DNA damage excision and repair replication by Setlow, Howard-Flanders, Hanawalt and their colleagues in the early 1960s, constituted the discovery of the ubiquitous pathway of nucleotide excision repair (NER). The serial steps in NER are similar in organisms from unicellular bacteria to complex mammals and plants, and involve recognition of lesions, adducts or structures that disrupt the DNA double helix, removal of a short oligonucleotide containing the offending lesion, synthesis of a repair patch copying the opposite undamaged strand, and ligation, to restore the DNA to its original form. The transcription-coupled repair (TCR) subpathway of NER, discovered nearly two decades later, is dedicated to the removal of lesions from the template DNA strands of actively transcribed genes. In this review I will outline the essential factors and complexes involved in NER in humans, and will comment on additional factors and metabolic processes that affect the efficiency of this important process. PMID:26388429

  15. Nuclear compartmentalization of DNA repair.

    PubMed

    Kalousi, Alkmini; Soutoglou, Evi

    2016-04-01

    The continuous threats on genome integrity by endogenous and exogenous sources have rendered cells competent to overcome these challenges by activating DNA repair pathways. A complex network of proteins and their modifications participate in orchestrated signaling cascades, which are induced in response to DNA damage and may determine the choice of repair pathway. In this review, we summarize recent findings in the field of DNA Double Strand Break repair with regard to the positioning of the break in the highly compartmentalized nucleus. We aim to highlight the importance of chromatin state along with the nuclear position of the DNA lesions on the choice of DNA repair pathway and maintenance of genome integrity. PMID:27266837

  16. Rotator cuff repair - series (image)

    MedlinePlus

    ... shoulder and arm bones. The tendons can be torn from overuse or injury. ... Surgery to repair a torn rotator cuff is usually very successful at relieving pain in the shoulder. The procedure is less predictable at returning strength ...

  17. Precision Instrument and Equipment Repairers.

    ERIC Educational Resources Information Center

    Wyatt, Ian

    2001-01-01

    Explains the job of precision instrument and equipment repairers, who work on cameras, medical equipment, musical instruments, watches and clocks, and industrial measuring devices. Discusses duties, working conditions, employment and earnings, job outlook, and skills and training. (JOW)

  18. How the brain repairs stuttering.

    PubMed

    Kell, Christian A; Neumann, Katrin; von Kriegstein, Katharina; Posenenske, Claudia; von Gudenberg, Alexander W; Euler, Harald; Giraud, Anne-Lise

    2009-10-01

    Stuttering is a neurodevelopmental disorder associated with left inferior frontal structural anomalies. While children often recover, stuttering may also spontaneously disappear much later after years of dysfluency. These rare cases of unassisted recovery in adulthood provide a model of optimal brain repair outside the classical windows of developmental plasticity. Here we explore what distinguishes this type of recovery from less optimal repair modes, i.e. therapy-induced assisted recovery and attempted compensation in subjects who are still affected. We show that persistent stuttering is associated with mobilization of brain regions contralateral to the structural anomalies for compensation attempt. In contrast, the only neural landmark of optimal repair is activation of the left BA 47/12 in the orbitofrontal cortex, adjacent to a region where a white matter anomaly is observed in persistent stutterers, but normalized in recovered subjects. These findings show that late repair of neurodevelopmental stuttering follows the principles of contralateral and perianomalous reorganization.

  19. [Dot1 and Set2 Histone Methylases Control the Spontaneous and UV-Induced Mutagenesis Levels in the Saccharomyces cerevisiae Yeasts].

    PubMed

    Kozhina, T N; Evstiukhina, T A; Peshekhonov, V T; Chernenkov, A Yu; Korolev, V G

    2016-03-01

    In the Saccharomyces cerevisiae yeasts, the DOT1 gene product provides methylation of lysine 79 (K79) of hi- stone H3 and the SET2 gene product provides the methylation of lysine 36 (K36) of the same histone. We determined that the dot1 and set2 mutants suppress the UV-induced mutagenesis to an equally high degree. The dot1 mutation demonstrated statistically higher sensitivity to the low doses of MMC than the wild type strain. The analysis of the interaction between the dot1 and rad52 mutations revealed a considerable level of spontaneous cell death in the double dot1 rad52 mutant. We observed strong suppression of the gamma-in- duced mutagenesis in the set2 mutant. We determined that the dot1 and set2 mutations decrease the sponta- neous mutagenesis rate in both single and d ouble mutants. The epistatic interaction between the dot1 and set2 mutations and almost similar sensitivity of the corresponding mutants to the different types of DNA damage allow one to conclude that both genes are involved in the control of the same DNA repair pathways, the ho- mologous-recombination-based and the postreplicative DNA repair.

  20. Aircraft Metal Skin Repair and Honeycomb Structure Repair; Sheet Metal Work 3: 9857.02.

    ERIC Educational Resources Information Center

    Dade County Public Schools, Miami, FL.

    The course helps students determine types of repairs, compute repair sizes, and complete the repair through surface protection. Course content includes goals, specific objectives, protection of metals, repairs to metal skin, and honeycomb structure repair. A bibliography and post-test are appended. A prerequisite for this course is mastery of the…

  1. Interactions of RecF protein with RecO, RecR, and single-stranded DNA binding proteins reveal roles for the RecF-RecO-RecR complex in DNA repair and recombination.

    PubMed

    Hegde, S P; Qin, M H; Li, X H; Atkinson, M A; Clark, A J; Rajagopalan, M; Madiraju, M V

    1996-12-10

    The products of the recF, recO, and recR genes are thought to interact and assist RecA in the utilization of single-stranded DNA precomplexed with single-stranded DNA binding protein (Ssb) during synapsis. Using immunoprecipitation, size-exclusion chromatography, and Ssb protein affinity chromatography in the absence of any nucleotide cofactors, we have obtained the following results: (i) RecF interacts with RecO, (ii) RecF interacts with RecR in the presence of RecO to form a complex consisting of RecF, RecO, and RecR (RecF-RecO-RecR); (iii) RecF interacts with Ssb protein in the presence of RecO. These data suggested that RecO mediates the interactions of RecF protein with RecR and with Ssb proteins. Incubation of RecF, RecO, RecR, and Ssb proteins resulted in the formation of RecF-RecO-Ssb complexes; i.e., RecR was excluded. Preincubation of RecF, RecO, and RecR proteins prior to addition of Ssb protein resulted in the formation of complexes consisting of RecF, RecO, RecR, and Ssb proteins. These data suggest that one role of RecF is to stabilize the interaction of RecR with RecO in the presence of Ssb protein. Finally, we found that interactions of RecF with RecO are lost in the presence of ATP. We discuss these results to explain how the RecF-RecO-RecR complex functions as an anti-Ssb factor. PMID:8962075

  2. UV protective effects of DNA repair enzymes and RNA lotion.

    PubMed

    Ke, Malcolm S; Camouse, Melissa M; Swain, Freddie R; Oshtory, Shaheen; Matsui, Mary; Mammone, Thomas; Maes, Daniel; Cooper, Kevin D; Stevens, Seth R; Baron, Elma D

    2008-01-01

    Solar UV radiation is known to cause immune suppression, believed to be a critical factor in cutaneous carcinogenesis. Although the mechanism is not entirely understood, DNA damage is clearly involved. Sunscreens function by attenuating the UV radiation that reaches the epidermis. However, once DNA damage ensues, repair mechanisms become essential for prevention of malignant transformation. DNA repair enzymes have shown efficacy in reducing cutaneous neoplasms among xeroderma pigmentosum patients. In vitro studies suggest that RNA fragments increase the resistance of human keratinocytes to UVB damage and enhance DNA repair but in vivo data are lacking. This study aimed to determine the effect of topical formulations containing either DNA repair enzymes (Micrococcus luteus) or RNA fragments (UVC-irradiated rabbit globin mRNA) on UV-induced local contact hypersensitivity (CHS) suppression in humans as measured in vivo using the contact allergen dinitrochlorobenzene. Immunohistochemistry was also employed in skin biopsies to evaluate the level of thymine dimers after UV. Eighty volunteers completed the CHS portion. A single 0.75 minimum erythema dose (MED) simulated solar radiation exposure resulted in 64% CHS suppression in unprotected subjects compared with unirradiated sensitized controls. In contrast, UV-induced CHS suppression was reduced to 19% with DNA repair enzymes, and 7% with RNA fragments. Sun protection factor (SPF) testing revealed an SPF of 1 for both formulations, indicating that the observed immune protection cannot be attributed to sunscreen effects. Biopsies from an additional nine volunteers showed an 18% decrease in thymine dimers by both DNA repair enzymes and RNA fragments, relative to unprotected UV-irradiated skin. These results suggest that RNA fragments may be useful as a photoprotective agent with in vivo effects comparable to DNA repair enzymes.

  3. Chlamydomonas reinhardtii: a convenient model system for the study of DNA repair in photoautotrophic eukaryotes.

    PubMed

    Vlcek, Daniel; Sevcovicová, Andrea; Sviezená, Barbara; Gálová, Eliska; Miadoková, Eva

    2008-01-01

    The green alga Chlamydomonas reinhardtii is a convenient model organism for the study of basic biological processes, including DNA repair investigations. This review is focused on the studies of DNA repair pathways in C. reinhardtii. Emphasis is given to the connection of DNA repair with other cellular functions, namely the regulation of the cell cycle. Comparison with the results of repair investigations that are already available revealed the presence of all basic repair pathways in C. reinhardtii as well as special features characteristic of this alga. Among others, the involvement of UVSE1 gene in recombinational repair and uniparental inheritance of chloroplast genome, the specific role of TRXH1 gene in strand break repair, the requirement of PHR1 gene for full activity of PHR2 gene, or encoding of two excision repair proteins by the single REX1 gene. Contrary to yeast, mammals and higher plants, C. reinhardtii does not appear to contain the ortholog of RAD6 gene, which plays an important role in DNA translesion synthesis and mutagenesis. Completed genome sequences will be a basis for molecular analyses allowing to explain the differences that have been observed in DNA repair of this alga in comparison with other model organisms.

  4. The RASSF1A Tumor Suppressor Regulates XPA-Mediated DNA Repair

    PubMed Central

    Donninger, Howard; Clark, Jennifer; Rinaldo, Francesca; Nelson, Nicholas; Barnoud, Thibaut; Schmidt, M. Lee; Hobbing, Katharine R.; Vos, Michele D.; Sils, Brian

    2014-01-01

    RASSF1A may be the most frequently inactivated tumor suppressor identified in human cancer so far. It is a proapoptotic Ras effector and plays an important role in the apoptotic DNA damage response (DDR). We now show that in addition to DDR regulation, RASSF1A also plays a key role in the DNA repair process itself. We show that RASSF1A forms a DNA damage-regulated complex with the key DNA repair protein xeroderma pigmentosum A (XPA). XPA requires RASSF1A to exert full repair activity, and RASSF1A-deficient cells exhibit an impaired ability to repair DNA. Moreover, a cancer-associated RASSF1A single-nucleotide polymorphism (SNP) variant exhibits differential XPA binding and inhibits DNA repair. The interaction of XPA with other components of the repair complex, such as replication protein A (RPA), is controlled in part by a dynamic acetylation/deacetylation cycle. We found that RASSF1A and its SNP variant differentially regulate XPA protein acetylation, and the SNP variant hyperstabilizes the XPA-RPA70 complex. Thus, we identify two novel functions for RASSF1A in the control of DNA repair and protein acetylation. As RASSF1A modulates both apoptotic DDR and DNA repair, it may play an important and unanticipated role in coordinating the balance between repair and death after DNA damage. PMID:25368379

  5. Effect of Finishing Time on Microleakage at the Composite-Repair Interface

    PubMed Central

    Shafiei, Fereshteh; Berahman, Nazanin; Niazi, Elmira

    2016-01-01

    Background: Repair is a conservative treatment of defective composite restoration. Sealing the repair interface is a critical factor to achieve successful repaired restorations. Objective: The aim of this study was to evaluatethe effect of three finishing times on the microleakage at the composite-repair interface. Method: Eighty composite specimens (Z250) were made and aged for eight weeks in water. They were randomly divided into four groups. In the control group, repairing was done with no surface treatment and using bonding agent. In groups 2 to 4, the specimens were repaired following roughening, etching and use of Adper Single Bond, and finished immediately, after 20 minutes and after 24 hours, respectively. After thermocycling, the microleakage at the repair interface was assessed using dye-penetration technique. The results were analyzed using Kruskal-Wallis and Mann-Whitney tests (α=0.05). Results: There was a significant difference among the four groups (P<0.001). The control group with the highest leakage showed a significant difference with the other groups (P<0.05). Immediate finishing showed a significantly higher leakage compared to 20-minute and 24-hour delayed finishing time (P<0.001). The two latter groups had no difference. Conclusion: Immediate finishing of the repaired restorations negatively affect the sealing at the repair interface, while 20-minute and 24-hour delayed finishing had no adverse effect on the interface sealing. PMID:27733876

  6. Increased Production of Clusterin in Biopsies of Repair Tissue following Autologous Chondrocyte Implantation

    PubMed Central

    Malda, Jos; Richardson, James B.; Roberts, Sally

    2013-01-01

    Objective. To characterize the immunolocalization of clusterin in the repair cartilage of patients having undergone autologous chondrocyte implantation (ACI) and evaluate correlation to clinical outcome. Design. Full-depth core biopsies of repair tissue were obtained from 38 patients who had undergone ACI at an average of 18 ± 13 months previously (range 8-67 months). The biopsies were snap frozen, cryosectioned, and clusterin production immunolocalized using a specific monoclonal clusterin antibody and compared with normal and osteoarthritic cartilage. Clinical outcome was assessed from patients preoperatively, at the time of biopsy, and annually postoperatively. Results. Intensity of immunostaining for clusterin decreased with age in healthy cartilage tissue. Clusterin was detected to a variable degree in 37 of the 38 ACI cartilage biopsies, in single and clustered chondrocytes, in the pericellular capsule and the cartilage extracellular matrix, as well as the osteocytes and osteoid within the bone. Chondrocytes in hyaline repair tissue were significantly more immunopositive than those in fibrocartilage repair tissue. Clinical outcome improved significantly post-ACI, but did not correlate with the presence of clusterin in the repair tissue. Conclusions. These results demonstrate the presence of clusterin in actively repairing human cartilage and indicate a different distribution of clusterin in this tissue compared to normal cartilage. Variability in clusterin staining in the repair tissue could indicate different states of chondrogenic differentiation. The clinical significance of clusterin within repair tissue is difficult to assess, although the ideal functioning repair tissue morphology should resemble that of healthy adult cartilage. PMID:26069669

  7. Assessment of the canine model of rotator cuff injury and repair

    PubMed Central

    Derwin, Kathleen A; Baker, Andrew R; Codsi, Michael J; Iannotti, Joseph P

    2007-01-01

    Animal shoulder models are used to systematically investigate the factors influencing rotator cuff injury and repair. Each model has advantages and disadvantages that must be considered in the context of the specific research questions being asked. Herein we evaluate the utility of the canine model for studies of acute, full-thickness rotator cuff tendon injury and repair. We found that time zero failure load is dependent on the suture type and configuration used for repair. Acute, full-width tendon repairs fail anatomically within the first days after surgery in the canine model, regardless of suture type, suture configuration or post-operative protocol. Robust scar tissue forms in the gap between the failed tendon end and the humerus, which can be visually, mechanically and histologically misconstrued as tendon if an objective test of repair connectivity is not performed. We conclude that a full-width injury and repair model in the canine will provide a rigorous test of whether a new repair strategy or post-operative protocol (such as casting or temporary muscle paralysis) can maintain repair integrity in a high load environment. Alternatively, a partial-width tendon injury model allows loads to be shared between the tendon repair and the remaining intact portion of the infraspinatus tendon and prohibits complete tendon retraction. Thus a partial-width injury in the canine may model the mechanical environment of many single tendon tears in the human injury condition and warrants further investigation. PMID:17560802

  8. Characterization of Postreplication Repair in Mutagen-Sensitive Strains of DROSOPHILA MELANOGASTER

    PubMed Central

    Boyd, J. B.; Setlow, R. B.

    1976-01-01

    Mutants of Drosophila melanogaster, with suspected repair deficiencies, were analyzed for their capacity to repair damage induced by X-rays and UV radiation. Analysis was performed on cell cultures derived from embryos of homozygous mutant stocks. Postreplication repair following UV radiation has been analyzed in mutant stocks derived from a total of ten complementation groups. Cultures were irradiated, pulse-labeled, and incubated in the dark prior to analysis by alkaline sucrose gradient centrifugation. Kinetics of the molecular weight increase in newly synthesized DNA were assayed after cells had been incubated in the presence or absence of caffeine. Two separate pathways of postreplication repair have been tentatively identified by mutants derived from four complementation groups. The proposed caffeine sensitive pathway (CAS) is defined by mutants which also disrupt meiosis. The second pathway (CIS) is caffeine insensitive and is not yet associated with meiotic functions. All mutants deficient in postreplication repair are also sensitive to nitrogen mustard. The mutants investigated display a normal capacity to repair single-strand breaks induced in DNA by X-rays, although two may possess a reduced capacity to repair damage caused by localized incorporation of high specific activity thymidine-3H. The data have been employed to construct a model for repair of UV-induced damage in Drosophila DNA. Implications of the model for DNA repair in mammals are discussed. PMID:826451

  9. A Biomechanical Comparison of All-Inside Meniscus Repair Techniques

    PubMed Central

    Chang, Jen-Huei; Shen, Hsain-Chung; Huang, Guo-Shu; Pan, Ru-Yu; Wu, Chi-Fang; Lee, Chian-Her; Chen, Qian

    2010-01-01

    Background The aim of this study was to assess the biomechanical characteristics of six all-inside meniscal single suture repair techniques using a porcine model. Materials and Methods Peripheral longitudinal tears were created in freshly isolated porcine menisci. Tears were repaired using the single vertical technique with six different repair complexes including those involving sutures (#2 FiberWire, #2 Ethibone, flexible anchors (Fast-Fix, RapidLoc), and rigid anchors (Meniscal-Dart, BioStinger). Displacement, ultimate failure strength, stiffness, and site of failure were measured using a Materials Testing System machine. An initial 2 N preload was applied, followed by loading between 5 and 20 N for 300 cycles. Failure strength was determined lastly by increasing tension at a rate of 5 mm/min until failure. Results Failure strength was highest in the #2 FiberWire group (175.6 N). This was significantly higher than in all other groups (P <0.05). The second highest failure load was evident in the #2 Ethibone group (113.8 N). This was significantly higher than in all other groups bar the #2 FiberWire group (P <0.05). Stiffness was also significantly higher in the #2 FiberWire group compared with all other groups (8.5 N/mm, P < 0.05). There were no between-group differences in displacement. When grouped by repair technique, failure load was significantly higher, and displacement was significantly lower, in suture compared with both flexible and rigid anchor repaired menisci (P < 0.01 for all comparisons). Although stiffness was also higher in the suture group, there were no significant between-group differences detected. Conclusions Suture techniques exhibited biomechanical superiority over biodegradable flexible and rigid anchor devices for meniscus repair. PMID:19328497

  10. Endovascular abdominal aortic aneurysm repair in the octogenarian.

    PubMed

    Brinkman, William T; Terramani, Thomas T; Najibi, Sasan; Weiss, Victor J; Salam, Atef A; Dodson, Thomas F; Smith, Robert B; Chaikof, Elliot L

    2004-07-01

    The aim of this study was to analyze patient outcomes following endovascular repair of infrarenal abdominal aortic aneurysms (EAR) among patients 80 years of age or older. In this study, reporting standards of the Ad Hoc Committee for Standardized Reporting Practices for Endovascular Aortic Aneurysm Repair of the Society of Vascular Surgery/American Association for Vascular Surgery (SVS/AAVS) were followed. Between August 8, 1996 and February 12, 2001 EAR was performed in 31 patients (29 male and 2 female) with an average age of 83 +/- 3 years and an average maximum aneurysm diameter of 59 +/- 7 mm. Overall technical success was 90% (28/31) with a single acute conversion and a 6% (2/32) incidence of major morbidity. There were no in-hospital deaths, but two patients (6%) died within 30 days of intervention. Four endoleaks, two type I and two type II, were observed within the first 30 days after endograft implantation and three new type II endoleaks were noted after implant periods that exceeded 1 month. Average follow-up was 16 months, with a single aneurysm-related death that occurred after late conversion to open repair, 2 years following initial endovascular treatment. Kaplan-Meier analysis revealed 3-, 12-, and 24-month estimated survivals of 93% (+/-5), 75% (+/-8), and 68% (+/-10), respectively. Clinical success rates were 90% (+/-5), 90% (+/-5), and 72% (+/-17) at 12, 24, and 36 months, respectively. We conclude that, in the octogenarian with mild to moderate medical comorbidities, endovascular aneurysm repair provides an alternative to open AAA repair with low operative morbidity and good clinical success rates. Elevated SVS/AAVS medical comorbidity scores were not associated with increased operative mortality rates, but they did show a trend toward decreased mid-term survival. Careful consideration of life expectancy and the probability of rupture, as with traditional AAA repair, should dictate necessity for intervention. PMID:15175935

  11. Development of an echocardiographic scoring system to predict biventricular repair in neonatal hypoplastic left heart complex.

    PubMed

    Mart, Christopher Robin; Eckhauser, Aaron Wesley

    2014-12-01

    Neonates born with borderline left heart hypoplasia, or hypoplastic left heart complex, can undergo biventricular repair while those with severe left heart hypoplasia require single ventricle palliation. Deciding which patients are candidates for biventricular repair may be very difficult since there are no scoring systems to predict biventricular repair in these patients. The purpose of this study is to develop an echocardiographic scoring system capable of predicting successful biventricular repair in neonatal hypoplastic left heart complex. The study cohort consisted of twenty consecutive neonates with hypoplastic left heart complex presenting between 9/2008 and 5/2013. Multiple retrospective echocardiographic measurements of the right and left heart were performed. Six patients with significant LH hypoplasia (patent mitral and aortic valves, small left ventricle) who had undergone single ventricle repair were used to validate the scoring system. Seventeen patients underwent biventricular repair and three underwent single ventricle repair. A scoring system (2V-Score) was developed using the equation {[(MV4C/AVPSLA) ÷ (LV4C/RV4C)] + MPA}/BSA. Using a cutoff value of ≤ 16.2, a biventricular repair would have been predicted with a sensitivity of 1.0, specificity 1.0, positive predictive value 1.0, negative predictive value 1.0, area under the ROC curve 1.0, and the p value was 0.0004. The 2V-Score was more accurate than the Rhodes, CHSS, or Discriminant scores in retrospectively predicting biventricular repair in this cohort. The 2V-Score shows promise in being able to predict a successful biventricular repair in patients with hypoplastic left heart complex but requires prospective validation prior to widespread clinical application.

  12. The current state of eukaryotic DNA base damage and repair

    PubMed Central

    Bauer, Nicholas C.; Corbett, Anita H.; Doetsch, Paul W.

    2015-01-01

    DNA damage is a natural hazard of life. The most common DNA lesions are base, sugar, and single-strand break damage resulting from oxidation, alkylation, deamination, and spontaneous hydrolysis. If left unrepaired, such lesions can become fixed in the genome as permanent mutations. Thus, evolution has led to the creation of several highly conserved, partially redundant pathways to repair or mitigate the effects of DNA base damage. The biochemical mechanisms of these pathways have been well characterized and the impact of this work was recently highlighted by the selection of Tomas Lindahl, Aziz Sancar and Paul Modrich as the recipients of the 2015 Nobel Prize in Chemistry for their seminal work in defining DNA repair pathways. However, how these repair pathways are regulated and interconnected is still being elucidated. This review focuses on the classical base excision repair and strand incision pathways in eukaryotes, considering both Saccharomyces cerevisiae and humans, and extends to some important questions and challenges facing the field of DNA base damage repair. PMID:26519467

  13. Role of DNA damage and repair in the function of eukaryotic genes: radiation-induced single-strand breaks and their rejoining in chromosomal and extrachromosomal ribosomal DNA of Tetrahymena

    SciTech Connect

    Chiu, S.M.; Oleinick, N.L.

    1980-04-01

    The production and rejoining of single-strand breaks (SSB) in chromosomal DNA and extrachromosomal ribosomal DNA (rDNA) were investigated after sublethal doses of ..gamma.. radiation to exponentially growing Tetrahymena. Hydrogen-3-labeled total nuclear DNA isolated from either control or irradiated cells was heat denatured and electrophoresed in agarose gels containing formaldehyde. Ribosomal DNA was identified by hybridization to (/sup 32/P)rRNA after transferring the DNA from the gels to nitrocellulose strips. It was found that (a) approximately 0.68 SSB is produced in each strand of rDNA exposed to 40 krad; (b) greater than 80% of SSB were rejoined within the first 20 min after irradiation in both chromosomal and rDNA; and (c) the rejoining process in both chromosomal and rDNA proceeded in the presence of inhibitors of protein synthesis, RNA synthesis, or oxidative metabolism. While the majority of SSB induced by 40 krad is rejoined within 20 min after irradiation, the resumption of rRNA synthesis does not occur until 30 min thereafter; it is concluded that the restoration of the normal size of the rDNA template is probably necessary but not sufficient for the resumption of rRNA synthesis.

  14. In situ analysis of repair processes for oxidative DNA damage in mammalian cells

    NASA Astrophysics Data System (ADS)

    Lan, Li; Nakajima, Satoshi; Oohata, Yoshitsugu; Takao, Masashi; Okano, Satoshi; Masutani, Mitsuko; Wilson, Samuel H.; Yasui, Akira

    2004-09-01

    Oxidative DNA damage causes blocks and errors in transcription and replication, leading to cell death and genomic instability. Although repair mechanisms of the damage have been extensively analyzed in vitro, the actual in vivo repair processes remain largely unknown. Here, by irradiation with an UVA laser through a microscope lens, we have conditionally produced single-strand breaks and oxidative base damage at restricted nuclear regions of mammalian cells. We showed, in real time after irradiation by using antibodies and GFP-tagged proteins, rapid and ordered DNA repair processes of oxidative DNA damage in human cells. Furthermore, we characterized repair pathways by using repair-defective mammalian cells and found that DNA polymerase accumulated at single-strand breaks and oxidative base damage by means of its 31- and 8-kDa domains, respectively, and that XRCC1 is essential for both polymerase -dependent and proliferating cell nuclear antigen-dependent repair pathways of single-strand breaks. Thus, the repair of oxidative DNA damage is based on temporal and functional interactions among various proteins operating at the site of DNA damage in living cells.

  15. A Coupled Thermal, Fluid Flow, and Solidification Model for the Processing of Single-Crystal Alloy CMSX-4 Through Scanning Laser Epitaxy for Turbine Engine Hot-Section Component Repair (Part I)

    NASA Astrophysics Data System (ADS)

    Acharya, Ranadip; Bansal, Rohan; Gambone, Justin J.; Das, Suman

    2014-12-01

    Scanning laser epitaxy (SLE) is a new laser-based additive manufacturing technology under development at the Georgia Institute of Technology. SLE is aimed at the creation of equiaxed, directionally solidified, and single-crystal deposits of nickel-based superalloys through the melting of alloy powders onto superalloy substrates using a fast scanning Nd:YAG laser beam. The fast galvanometer control movement of the laser (0.2 to 2 m/s) and high-resolution raster scanning (20 to 200 µm line spacing) enables superior thermal control over the solidification process and allows the production of porosity-free, crack-free deposits of more than 1000 µm thickness. Here, we present a combined thermal and fluid flow model of the SLE process applied to alloy CMSX-4 with temperature-dependent thermo-physical properties. With the scanning beam described as a moving line source, the instantaneous melt pool assumes a convex hull shape with distinct leading edge and trailing edge characteristics. Temperature gradients at the leading and trailing edges are of order 2 × 105 and 104 K/m, respectively. Detailed flow analysis provides insights on the flow characteristics of the powder incorporating into the melt pool, showing velocities of order 1 × 10-4 m/s. The Marangoni effect drives this velocity from 10 to 15 times higher depending on the operating parameters. Prediction of the solidification microstructure is based on conditions at the trailing edge of the melt pool. Time tracking of solidification history is incorporated into the model to couple the microstructure prediction model to the thermal-fluid flow model, and to predict the probability of the columnar-to-equiaxed transition. Qualitative agreement is obtained between simulation and experimental result.

  16. Transcription-coupled and global genome repair in the Saccharomyces cerevisiae RPB2 gene at nucleotide resolution.

    PubMed Central

    Tijsterman, M; Tasseron-de Jong, J G; van de Putte, P; Brouwer, J

    1996-01-01

    Repair of UV-induced cyclobutane pyrimidine dimers (CPDs) was examined at single nucleotide resolution in the yeast Saccharomyces cerevisiae, using an improved protocol for genomic end-labelling. To obtain the sensitivity required for adduct detection in yeast, an oligonucleotide-directed enrichment step was introduced into the current methodology developed for adduct detection in Escherichia coli. With this method, heterogeneous repair of CPDs within the RPB2 locus is observed. Individual CPDs positioned in the transcribed strand are removed very efficiently with identical kinetics. This fast repair starts within 23 bases downstream of the transcription initiation site. The non-transcribed strand of the active gene exhibits slow repair without detectable repair variations between individual lesions. In contrast, CPDs positioned in the promoter region show profound repair heterogeneity. Here, CPDs at specific sites are removed very quickly, with comparable rates to CPDs positioned in the transcribed strand, while at other positions lesions are not repaired at all during the period studied. Interestingly, the fast repair in the promoter region is dependent on the RAD7 and RAD16 genes, as are the slowly repaired CPDs in this region and in the non-transcribed strand. This indicates that the global genome repair pathway is not intrinsically slow and at specific positions can be as efficient as the transcription-coupled repair pathway. PMID:8836174

  17. Dorsal variant blister aneurysm repair.

    PubMed

    Couldwell, William T; Chamoun, Roukoz

    2012-01-01

    Dorsal variant proximal carotid blister aneurysms are treacherous lesions to manage. It is important to recognize this variant on preoperative angiographic imaging, in anticipation of surgical strategies for their treatment. Strategies include trapping the involved segment and revascularization if necessary. Other options include repair of the aneurysm rupture site directly. Given that these are not true berry aneurysms, repair of the rupture site involves wrapping or clip-grafting techniques. The case presented here was a young woman with a subarachnoid hemorrhage from a ruptured dorsal variant blister aneurysm. The technique used is demonstrated in the video and is a modified clip-wrap technique using woven polyester graft material. The patient was given aspirin preoperatively as preparation for the clip-wrap technique. It is the authors' current protocol to attempt a direct repair with clip-wrapping and leaving artery sacrifice with or without bypass as a salvage therapy if direct repair is not possible. Assessment of vessel patency after repair is performed by intraoperative Doppler and indocyanine green angiography. Intraoperative somatosensory and motor evoked potential monitoring is performed in all cases. The video can be found here: http://youtu.be/crUreWGQdGo.

  18. Reprogramming Cells for Brain Repair

    PubMed Central

    Guarino, Alyx T.; McKinnon, Randall D.

    2013-01-01

    At present there are no clinical therapies that can repair traumatic brain injury, spinal cord injury or degenerative brain disease. While redundancy and rewiring of surviving circuits can recover some lost function, the brain and spinal column lack sufficient endogenous stem cells to replace lost neurons or their supporting glia. In contrast, pre-clinical studies have demonstrated that exogenous transplants can have remarkable efficacy for brain repair in animal models. Mesenchymal stromal cells (MSCs) can provide paracrine factors that repair damage caused by ischemic injury, and oligodendrocyte progenitor cell (OPC) grafts give dramatic functional recovery from spinal cord injury. These studies have progressed to clinical trials, including human embryonic stem cell (hESC)-derived OPCs for spinal cord repair. However, ESC-derived allografts are less than optimal, and we need to identify a more appropriate donor graft population. The cell reprogramming field has developed the ability to trans-differentiate somatic cells into distinct cell types, a technology that has the potential to generate autologous neurons and glia which address the histocompatibility concerns of allografts and the tumorigenicity concerns of ESC-derived grafts. Further clarifying how cell reprogramming works may lead to more efficient direct reprogram approaches, and possibly in vivo reprogramming, in order to promote brain and spinal cord repair. PMID:24961526

  19. Essentials of skin laceration repair.

    PubMed

    Forsch, Randall T

    2008-10-15

    Skin laceration repair is an important skill in family medicine. Sutures, tissue adhesives, staples, and skin-closure tapes are options in the outpatient setting. Physicians should be familiar with various suturing techniques, including simple, running, and half-buried mattress (corner) sutures. Although suturing is the preferred method for laceration repair, tissue adhesives are similar in patient satisfaction, infection rates, and scarring risk in low skin-tension areas and may be more cost-effective. The tissue adhesive hair apposition technique also is effective in repairing scalp lacerations. The sting of local anesthesia injections can be lessened by using smaller gauge needles, administering the injection slowly, and warming or buffering the solution. Studies have shown that tap water is safe to use for irrigation, that white petrolatum ointment is as effective as antibiotic ointment in postprocedure care, and that wetting the wound as early as 12 hours after repair does not increase the risk of infection. Patient education and appropriate procedural coding are important after the repair. PMID:18953970

  20. Regulation of targeted gene repair by intrinsic cellular processes.

    PubMed

    Engstrom, Julia U; Suzuki, Takayuki; Kmiec, Eric B

    2009-02-01

    Targeted gene alteration (TGA) is a strategy for correcting single base mutations in the DNA of human cells that cause inherited disorders. TGA aims to reverse a phenotype by repairing the mutant base within the chromosome itself, avoiding the introduction of exogenous genes. The process of how to accurately repair a genetic mutation is elucidated through the use of single-stranded DNA oligonucleotides (ODNs) that can enter the cell and migrate to the nucleus. These specifically designed ODNs hybridize to the target sequence and act as a beacon for nucleotide exchange. The key to this reaction is the frequency with which the base is corrected; this will determine whether the approach becomes clinically relevant or not. Over the course of the last five years, workers have been uncovering the role played by the cells in regulating the gene repair process. In this essay, we discuss how the impact of the cell on TGA has evolved through the years and illustrate ways that inherent cellular pathways could be used to enhance TGA activity. We also describe the cost to cell metabolism and survival when certain processes are altered to achieve a higher frequency of repair.

  1. Practical aspects of coating repair

    SciTech Connect

    Munger, C.G.

    1980-02-01

    Detailed information is given concerning the types of coatings failures that are amenable to repair and materials and methods effective in making them. Coatings failure types are analyzed, and recommended surface preparation for several types of failure are described in detail. Consequences of improper surface preparation are emphasized. Precautions necessary for selection of materials and for application methods effective in applying coatings over old coatings are presented in detail. Characteristics and causes are given for pinpoint rusting, delamination, chalking, and undercutting by rust. Characteristics and causes of gas and liquid blisters are described and methods of repairing coating underneath them are detailed. Special attention is given to repairs on galvanizing and inorganic zinc-loaded coatings and the correct procedures of surface preparation and overcoating. Importance of time after start of failure to begin recoating is emphasized.

  2. Repair Pathway Choices and Consequences at the Double-Strand Break.

    PubMed

    Ceccaldi, Raphael; Rondinelli, Beatrice; D'Andrea, Alan D

    2016-01-01

    DNA double-strand breaks (DSBs) are cytotoxic lesions that threaten genomic integrity. Failure to repair a DSB has deleterious consequences, including genomic instability and cell death. Indeed, misrepair of DSBs can lead to inappropriate end-joining events, which commonly underlie oncogenic transformation due to chromosomal translocations. Typically, cells employ two main mechanisms to repair DSBs: homologous recombination (HR) and classical nonhomologous end joining (C-NHEJ). In addition, alternative error-prone DSB repair pathways, namely alternative end joining (alt-EJ) and single-strand annealing (SSA), have been recently shown to operate in many different conditions and to contribute to genome rearrangements and oncogenic transformation. Here, we review the mechanisms regulating DSB repair pathway choice, together with the potential interconnections between HR and the annealing-dependent error-prone DSB repair pathways.

  3. Arthroscopic Double-Row Transosseous Equivalent Rotator Cuff Repair with a Knotless Self-Reinforcing Technique

    PubMed Central

    Mook, William R.; Greenspoon, Joshua A.; Millett, Peter J.

    2016-01-01

    Background: Rotator cuff tears are a significant cause of shoulder morbidity. Surgical techniques for repair have evolved to optimize the biologic and mechanical variables critical to tendon healing. Double-row repairs have demonstrated superior biomechanical advantages to a single-row. Methods: The preferred technique for rotator cuff repair of the senior author was reviewed and described in a step by step fashion. The final construct is a knotless double row transosseous equivalent construct. Results: The described technique includes the advantages of a double-row construct while also offering self reinforcement, decreased risk of suture cut through, decreased risk of medial row overtensioning and tissue strangulation, improved vascularity, the efficiency of a knotless system, and no increased risk for subacromial impingement from the burden of suture knots. Conclusion: Arthroscopic knotless double row rotator cuff repair is a safe and effective method to repair rotator cuff tears. PMID:27733881

  4. Breaking bad: The mutagenic effect of DNA repair.

    PubMed

    Chen, Jia; Furano, Anthony V

    2015-08-01

    Species survival depends on the faithful replication of genetic information, which is continually monitored and maintained by DNA repair pathways that correct replication errors and the thousands of lesions that arise daily from the inherent chemical lability of DNA and the effects of genotoxic agents. Nonetheless, neutrally evolving DNA (not under purifying selection) accumulates base substitutions with time (the neutral mutation rate). Thus, repair processes are not 100% efficient. The neutral mutation rate varies both between and within chromosomes. For example it is 10-50 fold higher at CpGs than at non-CpG positions. Interestingly, the neutral mutation rate at non-CpG sites is positively correlated with CpG content. Although the basis of this correlation was not immediately apparent, some bioinformatic results were consistent with the induction of non-CpG mutations by DNA repair at flanking CpG sites. Recent studies with a model system showed that in vivo repair of preformed lesions (mismatches, abasic sites, single stranded nicks) can in fact induce mutations in flanking DNA. Mismatch repair (MMR) is an essential component for repair-induced mutations, which can occur as distant as 5 kb from the introduced lesions. Most, but not all, mutations involved the C of TpCpN (G of NpGpA) which is the target sequence of the C-preferring single-stranded DNA specific APOBEC deaminases. APOBEC-mediated mutations are not limited to our model system: Recent studies by others showed that some tumors harbor mutations with the same signature, as can intermediates in RNA-guided endonuclease-mediated genome editing. APOBEC deaminases participate in normal physiological functions such as generating mutations that inactivate viruses or endogenous retrotransposons, or that enhance immunoglobulin diversity in B cells. The recruitment of normally physiological error-prone processes during DNA repair would have important implications for disease, aging and evolution. This perspective

  5. Breaking bad: The mutagenic effect of DNA repair.

    PubMed

    Chen, Jia; Furano, Anthony V

    2015-08-01

    Species survival depends on the faithful replication of genetic information, which is continually monitored and maintained by DNA repair pathways that correct replication errors and the thousands of lesions that arise daily from the inherent chemical lability of DNA and the effects of genotoxic agents. Nonetheless, neutrally evolving DNA (not under purifying selection) accumulates base substitutions with time (the neutral mutation rate). Thus, repair processes are not 100% efficient. The neutral mutation rate varies both between and within chromosomes. For example it is 10-50 fold higher at CpGs than at non-CpG positions. Interestingly, the neutral mutation rate at non-CpG sites is positively correlated with CpG content. Although the basis of this correlation was not immediately apparent, some bioinformatic results were consistent with the induction of non-CpG mutations by DNA repair at flanking CpG sites. Recent studies with a model system showed that in vivo repair of preformed lesions (mismatches, abasic sites, single stranded nicks) can in fact induce mutations in flanking DNA. Mismatch repair (MMR) is an essential component for repair-induced mutations, which can occur as distant as 5 kb from the introduced lesions. Most, but not all, mutations involved the C of TpCpN (G of NpGpA) which is the target sequence of the C-preferring single-stranded DNA specific APOBEC deaminases. APOBEC-mediated mutations are not limited to our model system: Recent studies by others showed that some tumors harbor mutations with the same signature, as can intermediates in RNA-guided endonuclease-mediated genome editing. APOBEC deaminases participate in normal physiological functions such as generating mutations that inactivate viruses or endogenous retrotransposons, or that enhance immunoglobulin diversity in B cells. The recruitment of normally physiological error-prone processes during DNA repair would have important implications for disease, aging and evolution. This perspective

  6. Techniques in Endovascular Aneurysm Repair

    PubMed Central

    Phade, Sachin V.; Garcia-Toca, Manuel; Kibbe, Melina R.

    2011-01-01

    Endovascular repair of infrarenal abdominal aortic aneurysms (EVARs) has revolutionized the treatment of aortic aneurysms, with over half of elective abdominal aortic aneurysm repairs performed endoluminally each year. Since the first endografts were placed two decades ago, many changes have been made in graft design, operative technique, and management of complications. This paper summarizes modern endovascular grafts, considerations in preoperative planning, and EVAR techniques. Specific areas that are addressed include endograft selection, arterial access, sheath delivery, aortic branch management, graft deployment, intravascular ultrasonography, pressure sensors, management of endoleaks and compressed limbs, and exit strategies. PMID:22121487

  7. Proximal Rectus Femoris Avulsion Repair.

    PubMed

    Dean, Chase S; Arbeloa-Gutierrez, Lucas; Chahla, Jorge; Pascual-Garrido, Cecilia

    2016-06-01

    Proximal rectus femoris tendon avulsions are rare and occur mostly in male athletes. Currently, the standard of care for complete tendinous avulsions of the direct arm of the rectus femoris is nonoperative treatment. However, surgical repair may be considered in high-level athletes who have a high demand for repetitive hip flexion performed in an explosive manner or in patients in whom nonoperative treatment has failed. The purpose of this technical note is to describe the method for surgical repair of the proximal direct arm of the rectus femoris to its origin at the anterior inferior iliac spine using suture anchors. PMID:27656376

  8. Mountain Plains Learning Experience Guide: Automotive Repair. Course: Engine Repair.

    ERIC Educational Resources Information Center

    Schramm, C.; Osland, Walt

    One of twelve individualized courses included in an automotive repair curriculum, this course covers theory and construction, inspection diagnoses, and service and overhaul of automotive engines. The course is comprised of five units: (1) Fundamentals of Four-Cycle Engines, (2) Engine Construction, (3) Valve Train, (4) Lubricating Systems, and (5)…

  9. Lead exposure and radiator repair work.

    PubMed

    Lussenhop, D H; Parker, D L; Barklind, A; McJilton, C

    1989-11-01

    In 1986, the ambient air for lead in radiator repair shops in the Minneapolis-St. Paul metropolitan area exceeded the Occupational Safety and Health Administration (OSHA) action level in nine of 12 shops sampled by Minnesota OSHA. We therefore sought to determine the prevalence of lead exposure/toxicity in this industry. Thirty-five radiator shops were identified, 30 were visited, and 53 workers were studied. The mean blood lead level was 1.53 (range 0.24-2.80). Seventeen individuals had blood lead levels greater than or equal to 1.93 mumol/L (40 micrograms/dl). The mean zinc protoporphyrin level (ZPP) was 0.55 mumol/L (range 0.16-1.43). No single worksite or personal characteristic was a strong determinant of either blood lead or ZPP level.

  10. Final report [DNA Repair and Mutagenesis - 1999

    SciTech Connect

    Walker, Graham C.

    2001-05-30

    The meeting, titled ''DNA Repair and Mutagenesis: Mechanism, Control, and Biological Consequences'', was designed to bring together the various sub-disciplines that collectively comprise the field of DNA Repair and Mutagenesis. The keynote address was titled ''Mutability Doth Play Her Cruel Sports to Many Men's Decay: Variations on the Theme of Translesion Synthesis.'' Sessions were held on the following themes: Excision repair of DNA damage; Transcription and DNA excision repair; UmuC/DinB/Rev1/Rad30 superfamily of DNA polymerases; Cellular responses to DNA damage, checkpoints, and damage tolerance; Repair of mismatched bases, mutation; Genome-instability, and hypermutation; Repair of strand breaks; Replicational fidelity, and Late-breaking developments; Repair and mutation in challenging environments; and Defects in DNA repair: consequences for human disease and aging.

  11. Early Outcome of Primary Repair in Colonic Injury.

    PubMed

    Uddin, M A; Reza, E R; Islam, M S; Hoque, M R; Hussain, M F; Alam, I; Sazzad, M F; Biswas, N; Kader, M S; Malek, M S; Sultana, F; Rahman, K S

    2016-07-01

    The management of the colon injury remains controversial in spite of a number of divergent reports during the past decade. Previously surgeons were reluctant to do primary anastomosis but now-a-days they are doing primary repair with good results. The present study is designed to see the early outcomes of primary repair in colonic injury. This prospective observational study performed at Dhaka Medical College Hospital, Dhaka, Bangladesh from January 2013 to June 2013 with allocation of 50 patients with colonic injury who underwent laparotomy with primary repair of that injury in the department of Casualty Surgery. A primary repair was performed after freshening the edges or by resection and primary anastomosis with 3.0 round-body Vicryl by single layer extra mucosal interrupted suture. Data processed using software SPSS version 16.0. For all analytical results a p value <0.05 was considered significant. In this study the commonest site of injury were transvers colon and sigmoid colon 38.0% in each. Out of 50 respondents, 5(10.0%) developed burst abdomen, 1(2.0%) developed entero-cutaneous fistula with none had paralytic ileus or septicaemia or pelvic collection. No mortality observed. This study showed that the increasing in colon injury scale (CIS) score culminate into increasing rate of postoperative complication & post operative complications were more at left colon (24%). On basis of our findings, we recommend the primary repair is a safe and effective surgical technique for addressing the large gut injury. Unnecessary proximal diversions should be avoided. According to our experience, we believe that the policy of primary repair of colon injuries can be applied more liberally in majority of patients with high success rate. PMID:27612892

  12. Cell resistance to the Cytolethal Distending Toxin involves an association of DNA repair mechanisms

    PubMed Central

    Bezine, Elisabeth; Malaisé, Yann; Loeuillet, Aurore; Chevalier, Marianne; Boutet-Robinet, Elisa; Salles, Bernard; Mirey, Gladys; Vignard, Julien

    2016-01-01

    The Cytolethal Distending Toxin (CDT), produced by many bacteria, has been associated with various diseases including cancer. CDT induces DNA double-strand breaks (DSBs), leading to cell death or mutagenesis if misrepaired. At low doses of CDT, other DNA lesions precede replication-dependent DSB formation, implying that non-DSB repair mechanisms may contribute to CDT cell resistance. To address this question, we developed a proliferation assay using human cell lines specifically depleted in each of the main DNA repair pathways. Here, we validate the involvement of the two major DSB repair mechanisms, Homologous Recombination and Non Homologous End Joining, in the management of CDT-induced lesions. We show that impairment of single-strand break repair (SSBR), but not nucleotide excision repair, sensitizes cells to CDT, and we explore the interplay of SSBR with the DSB repair mechanisms. Finally, we document the role of the replicative stress response and demonstrate the involvement of the Fanconi Anemia repair pathway in response to CDT. In conclusion, our work indicates that cellular survival to CDT-induced DNA damage involves different repair pathways, in particular SSBR. This reinforces a model where CDT-related genotoxicity primarily involves SSBs rather than DSBs, underlining the importance of cell proliferation during CDT intoxication and pathogenicity. PMID:27775089

  13. A role for Saccharomyces cerevisiae Tpa1 protein in direct alkylation repair.

    PubMed

    Shivange, Gururaj; Kodipelli, Naveena; Monisha, Mohan; Anindya, Roy

    2014-12-26

    Alkylating agents induce cytotoxic DNA base adducts. In this work, we provide evidence to suggest, for the first time, that Saccharomyces cerevisiae Tpa1 protein is involved in DNA alkylation repair. Little is known about Tpa1 as a repair protein beyond the initial observation from a high-throughput analysis indicating that deletion of TPA1 causes methyl methane sulfonate sensitivity in S. cerevisiae. Using purified Tpa1, we demonstrate that Tpa1 repairs both single- and double-stranded methylated DNA. Tpa1 is a member of the Fe(II) and 2-oxoglutarate-dependent dioxygenase family, and we show that mutation of the amino acid residues involved in cofactor binding abolishes the Tpa1 DNA repair activity. Deletion of TPA1 along with the base excision repair pathway DNA glycosylase MAG1 renders the tpa1Δmag1Δ double mutant highly susceptible to methylation-induced toxicity. We further demonstrate that the trans-lesion synthesis DNA polymerase Polζ (REV3) plays a key role in tolerating DNA methyl-base lesions and that tpa1Δmag1revΔ3 triple mutant is extremely susceptible to methylation-induced toxicity. Our results indicate a synergism between the base excision repair pathway and direct alkylation repair by Tpa1 in S. cerevisiae. We conclude that Tpa1 is a hitherto unidentified DNA repair protein in yeast and that it plays a crucial role in reverting alkylated DNA base lesions and cytotoxicity.

  14. 24 CFR 206.47 - Property standards; repair work.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... be repaired in order to ensure that the repaired property will serve as adequate security for the insured mortgage. (b) Assurance that repairs are made. The mortgage may be closed before the repair...

  15. Loss of DNA repair capacity during successive subcultures of primary rat fibroblasts

    PubMed Central

    1977-01-01

    Cultures of fibroblasts from newborn rats and successive subcultures of these cells were treated with 4-nitroquinoline-1-oxide to induce DNA repair. DNA from the cultures was examined by velocity sedimentation in alkaline sucrose gradients immediately after drug treatment and after a post-treatment incubation period of 3 h. Early passage cells were able to repair the damage that appeared as single strand breaks, however, by the seventh subculture this activity was not apparent. Measurements of repair synthesis showed a partial loss of this capacity with successive subculture. The results fit a model in which 4NQO causes two kinds of DNA modification, one of which is alkali labile and appears as a single- strand break. Both modifications are subject to excision repair, but each is recognized initially by a specific endonuclease. In the late passage cells, the endonuclease specific for the alkali labile modification is absent. PMID:407232

  16. An experimental investigation on the ultimate strength of epoxy repaired braced partial infilled RC frames

    NASA Astrophysics Data System (ADS)

    Dubey, Shailendra Kumar Damodar; Kute, Sunil

    2014-09-01

    Due to earthquake, buildings are damaged partially or completely. Particularly structures with soft storey are mostly affected. In general, such damaged structures are repaired and reused. In this regard, an experimental investigation was planned and conducted on models of single-bay, single-storey of partial concrete infilled reinforced concrete (RC) frames up to collapse with corner, central and diagonal steel bracings. Such collapsed frames were repaired with epoxy resin and retested. The initiative was to identify the behaviour, extent of restored ultimate strength and deflection of epoxy-retrofitted frames in comparison to the braced RC frames. The performance of such frames has been considered only for lateral loads. In comparison to bare RC frames, epoxy repaired partial infilled frames have significant increase in the lateral load capacity. Central bracing is more effective than corner and diagonal bracing. For the same load, epoxy repaired frames have comparable deflection than similar braced frames.

  17. Influence of XRCC1 Genetic Polymorphisms on Ionizing Radiation-Induced DNA Damage and Repair

    PubMed Central

    Sterpone, Silvia; Cozzi, Renata

    2010-01-01

    It is well known that ionizing radiation (IR) can damage DNA through a direct action, producing single- and double-strand breaks on DNA double helix, as well as an indirect effect by generating oxygen reactive species in the cells. Mammals have evolved several and distinct DNA repair pathways in order to maintain genomic stability and avoid tumour cell transformation. This review reports important data showing a huge interindividual variability on sensitivity to IR and in susceptibility to developing cancer; this variability is principally represented by genetic polymorphisms, that is, DNA repair gene polymorphisms. In particular we have focussed on single nucleotide polymorphisms (SNPs) of XRCC1, a gene that encodes for a scaffold protein involved basically in Base Excision Repair (BER). In this paper we have reported and presented recent studies that show an influence of XRCC1 variants on DNA repair capacity and susceptibility to breast cancer. PMID:20798883

  18. [A Nobel Prize for DNA repair].

    PubMed

    Jordan, Bertrand

    2016-01-01

    This year's Nobel Prize for chemistry recognizes the seminal contributions of three researchers who discovered the existence and the basic mechanisms of DNA repair: base excision repair, mismatch repair, and nucleotide excision repair. They have since been joined by many scientists elucidating diverse aspects of these complex mechanisms that now constitute a thriving research field with many applications, notably for understanding oncogenesis and devising more effective therapies. PMID:26850617

  19. [A Nobel Prize for DNA repair].

    PubMed

    Jordan, Bertrand

    2016-01-01

    This year's Nobel Prize for chemistry recognizes the seminal contributions of three researchers who discovered the existence and the basic mechanisms of DNA repair: base excision repair, mismatch repair, and nucleotide excision repair. They have since been joined by many scientists elucidating diverse aspects of these complex mechanisms that now constitute a thriving research field with many applications, notably for understanding oncogenesis and devising more effective therapies.

  20. Outcome of quadriceps tendon repair.

    PubMed

    Puranik, Gururaj S; Faraj, Adnan

    2006-04-01

    Complete rupture of the quadriceps tendon is a well-described injury. There is a scarcity of literature relating to the outcome of patients with this injury after surgery. We undertook a retrospective analysis of patients who had surgical repair of their quadriceps tendon at our institution over a 13-year period, totalling 21 patients. Males were more commonly affected, with a male/female ratio of 4:1. The peak incidence was in the sixth decade of life. Assessment consisted of the completion of a functional knee questionnaire and a clinical examination. Symptomatic outcome following surgical repair was good with a mean symptom score generated of 19.16 out of a maximum of 25 using the Rougraff et al scoring system. Most of the patients returned to their pre-injury level of activity. Five degrees deficit and extension lag was present in three patients; these patients had the quadriceps repaired using transosseous sutures. Patients who had direct repair of the tendon using the Bunnell technique had lower Rougraff scores than the rest.

  1. How the Brain Repairs Stuttering

    ERIC Educational Resources Information Center

    Kell, Christian A.; Neumann, Katrin; von Kriegstein, Katharina; Posenenske, Claudia; von Gudenberg, Alexander W.; Euler, Harald; Giraud, Anne-Lise

    2009-01-01

    Stuttering is a neurodevelopmental disorder associated with left inferior frontal structural anomalies. While children often recover, stuttering may also spontaneously disappear much later after years of dysfluency. These rare cases of unassisted recovery in adulthood provide a model of optimal brain repair outside the classical windows of…

  2. Microwave Oven Repair. Teacher Edition.

    ERIC Educational Resources Information Center

    Smreker, Eugene

    This competency-based curriculum guide for teachers addresses the skills a technician will need to service microwave ovens and to provide customer relations to help retain the customer's confidence in the product and trust in the service company that performs the repair. The guide begins with a task analysis, listing 20 cognitive tasks and 5…

  3. Computer Equipment Repair Curriculum Guide.

    ERIC Educational Resources Information Center

    Reneau, Fred; And Others

    This guide is intended for use in a course to train students to repair computer equipment and perform related administrative and customer service tasks. Addressed in the individual units are the following topics (with selected subtopics in brackets): performing administrative functions (preparing service bills, maintaining accounts and labor…

  4. Minilaparoscopy For Inguinal Hernia Repair

    PubMed Central

    Malcher, Flavio; Cavazzola, Leandro Totti; Araujo, Guilherme D. E.; Silva, José Antônio Da Cunha E.; Rao, Prashanth; Iglesias, Antonio Carlos

    2016-01-01

    Background and Objectives: Inguinal hernia repair is among the most common procedures performed worldwide and the laparoscopic totally extraperitoneal (TEP) approach is a recognized and effective surgical technique. Although technically advantageous because of the option of no mesh fixation and no need for creation of a peritoneal flap resulting, in less postoperative pain and faster recovery, TEP has not achieved the popularity it deserves, mainly because of its complexity and steep learning curve. Minilaparoscopy was first described in the 1990s and has recently gained significantly from better instrumentation that may increase TEP's effectiveness and acceptance. We performed a prospective study, to analyze the outcomes of minilaparoscopy in pain and operative time when compared to the conventional laparoscopic technique in hernia repair. Methods: Fifty-eight laparoscopic inguinal hernia repairs were performed: 36 by traditional laparoscopic technique and 22 by minilaparoscopic instruments (mini). A study protocol was applied prospectively for data collection. Variables analyzed were early postoperative pain (at hour 6 after procedure), pain at discharge, use of on-demand analgesics, and operative time. Results: The mini group presented reduced early postoperative pain and operative time. The present study also suggests less postoperative pain at discharge with mini procedures, although this difference was not statistically significant. No difference between the groups regarding on-demand use of analgesics was found. Conclusions: This study corroborates findings in previously published papers that have shown the feasibility of minilaparoscopy in laparoscopic TEP hernia repair and its benefits regarding postoperative pain, operative time, and aesthetic outcomes. PMID:27777499

  5. Simplified Knotless Mattress Repair of Type II SLAP Lesions.

    PubMed

    Chia, Marcus Robert; Hatrick, Cameron

    2015-12-01

    Arthroscopic repair of lesions of the superior labrum and biceps anchor has been shown to provide good to excellent results. We describe a simplified arthroscopic surgical technique using a single knotless anchor with a mattress suture configuration. This technique provides an effective and reproducible method to reattach and re-create the normal appearance of the superior labrum and biceps anchor in a time-efficient manner without the need for knot tying.

  6. Robotic repair of scrotal bladder hernia during robotic prostatectomy.

    PubMed

    Sung, Ee-Rah; Park, Sung Yul; Ham, Won Sik; Jeong, Wooju; Lee, Woo Jung; Rha, Koon Ho

    2008-09-01

    We report a case of scrotal bladder hernia in a 68-year-old man who was also diagnosed with prostate cancer. We fixed the herniated portion of the bladder using robotics after having successfully accomplished robotic prostatectomy. To the best of our knowledge, this is the first case report on simultaneous repair of scrotal bladder hernia and prostate cancer where both pathological findings have been treated with the assistance of robotics at a single operation. PMID:27628264

  7. Modeling the induced mutation process in bacterial cells with defects in excision repair system

    NASA Astrophysics Data System (ADS)

    Bugay, A. N.; Vasilyeva, M. A.; Krasavin, E. A.; Parkhomenko, A. Yu.

    2015-12-01

    A mathematical model of the UV-induced mutation process in Escherichia coli cells with defects in the uvrA and polA genes has been developed. The model describes in detail the reaction kinetics for the excision repair system. The number of mismatches as a result of translesion synthesis is calculated for both wild-type and mutant cells. The effect of temporal modulation of the number of single-stranded DNA during postreplication repair has been predicted. A comparison of effectiveness of different repair systems has been conducted.

  8. Genetic variants in DNA repair pathways are not associated with disease progression among multiple myeloma patients.

    PubMed

    Thyagarajan, Bharat; Arora, Mukta; Guan, Weihua; Barcelo, Helene; Jackson, Scott; Kumar, Shaji; Gertz, Morie

    2013-11-01

    DNA damage induced by high dose melphalan and autologous transplantation is repaired by the nucleotide excision repair (NER) and base excision repair (BER) pathways. We evaluated the association between single nucleotide polymorphisms (SNPs) (n=311) in the NER and BER pathways and disease progression in 695 multiple myeloma patients who underwent autologous transplantation. None of the SNPs were associated with disease progression. Pathway based analyses showed that the NER pathway had a borderline association with disease progression (p=0.09). These findings suggest that common variation in the NER and BER pathways do not substantially influence disease progression in multiple myeloma patients.

  9. Standardized Curriculum for Shoe and Boot Repair.

    ERIC Educational Resources Information Center

    Mississippi State Dept. of Education, Jackson. Office of Vocational, Technical and Adult Education.

    This curriculum guide for shoe and boot repair was developed by the state of Mississippi to standardize vocational education course titles and core contents. The objectives contained in this document are common to all shoe and boot repair programs in the state. The guide contains objectives for shoe and boot repair I and II courses. Units in…

  10. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 1 2014-07-01 2014-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which...

  11. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 1 2010-07-01 2010-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which...

  12. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 1 2012-07-01 2012-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which...

  13. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 1 2013-07-01 2013-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which...

  14. 33 CFR 115.40 - Bridge repairs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 1 2011-07-01 2011-07-01 false Bridge repairs. 115.40 Section 115.40 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY BRIDGES BRIDGE LOCATIONS AND CLEARANCES; ADMINISTRATIVE PROCEDURES § 115.40 Bridge repairs. Repairs to a bridge which...

  15. Standardized Curriculum for Small Engine Repair.

    ERIC Educational Resources Information Center

    Mississippi State Dept. of Education, Jackson. Office of Vocational, Technical and Adult Education.

    This curriculum guide for small engine repair was developed by the state of Mississippi to standardize vocational education course titles and core contents. The objectives contained in this document are common to all small engine repair programs in the state. The guide contains objectives for small engine repair I and II courses. Units in course I…

  16. 46 CFR Sec. 19 - Ship Repair Summaries.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 8 2010-10-01 2010-10-01 false Ship Repair Summaries. Sec. 19 Section 19 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY PROCEDURE FOR ACCOMPLISHMENT OF VESSEL REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR...

  17. 46 CFR Sec. 19 - Ship Repair Summaries.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 8 2014-10-01 2014-10-01 false Ship Repair Summaries. Sec. 19 Section 19 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY PROCEDURE FOR ACCOMPLISHMENT OF VESSEL REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR...

  18. 46 CFR Sec. 19 - Ship Repair Summaries.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 8 2013-10-01 2013-10-01 false Ship Repair Summaries. Sec. 19 Section 19 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY PROCEDURE FOR ACCOMPLISHMENT OF VESSEL REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR...

  19. 46 CFR Sec. 19 - Ship Repair Summaries.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 8 2011-10-01 2011-10-01 false Ship Repair Summaries. Sec. 19 Section 19 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY PROCEDURE FOR ACCOMPLISHMENT OF VESSEL REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR...

  20. 46 CFR Sec. 19 - Ship Repair Summaries.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 8 2012-10-01 2012-10-01 false Ship Repair Summaries. Sec. 19 Section 19 Shipping MARITIME ADMINISTRATION, DEPARTMENT OF TRANSPORTATION A-NATIONAL SHIPPING AUTHORITY PROCEDURE FOR ACCOMPLISHMENT OF VESSEL REPAIRS UNDER NATIONAL SHIPPING AUTHORITY MASTER LUMP SUM REPAIR...

  1. Fix-It Careers: Jobs in Repair

    ERIC Educational Resources Information Center

    Torpey, Elka Maria

    2010-01-01

    From auto mechanic to HVAC technicians, many occupations require repair skills. For jobseekers with the right skills, there are many advantages to a repair career. Repair work provides millions of jobs throughout the United States. Wages are often higher than average. And in many occupations, the employment outlook is bright. Plus, most repair…

  2. 40 CFR 65.105 - Leak repair.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... leak. (3) Maximum instrument reading measured by Method 21 of appendix A of 40 CFR part 60 at the time... 40 Protection of Environment 16 2012-07-01 2012-07-01 false Leak repair. 65.105 Section 65.105... FEDERAL AIR RULE Equipment Leaks § 65.105 Leak repair. (a) Leak repair schedule. The owner or...

  3. Welding/brazing for Space Station repair

    NASA Astrophysics Data System (ADS)

    Dickinson, David W.; Babel, H. W.; Conaway, H. R.; Hooper, W. H.

    Viewgraphs on welding/brazing for space station repair are presented. Topics covered include: fabrication and repair candidates; debris penetration of module panel; welded repair patch; mechanical assembly of utility fluid line; space station utility systems; Soviet aerospace fabrication - an overview; and processes under consideration.

  4. Auto Body Repair and Repainting: Instructional Units.

    ERIC Educational Resources Information Center

    Manuel, Edward F.; Penner, Wayman R.

    The guide contains 11 sections, each consisting of one or more units of instruction designed to provide students with entry-level skills in auto body repair. The sections deal with: introductory and related information; body and frame construction; tools; welding; basic metal repair; hardware, glass, and trim; major metal repair; refinishing;…

  5. 33 CFR 127.405 - Repairs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Repairs. 127.405 Section 127.405... Facilities Handling Liquefied Natural Gas Maintenance § 127.405 Repairs. The operator shall ensure that— (a) Equipment repairs are made so that— (1) The equipment continues to meet the applicable requirements in...

  6. 30 CFR 57.14104 - Tire repairs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tire repairs. 57.14104 Section 57.14104 Mineral... Devices and Maintenance Requirements § 57.14104 Tire repairs. (a) Before a tire is removed from a vehicle for tire repair, the valve core shall be partially removed to allow for gradual deflation and...

  7. 30 CFR 56.14104 - Tire repairs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Tire repairs. 56.14104 Section 56.14104 Mineral... Devices and Maintenance Requirements § 56.14104 Tire repairs. (a) Before a tire is removed from a vehicle for tire repair, the valve core shall be partially removed to allow for gradual deflation and...

  8. 26 CFR 1.162-4 - Repairs.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 26 Internal Revenue 2 2010-04-01 2010-04-01 false Repairs. 1.162-4 Section 1.162-4 Internal... TAXES (CONTINUED) Itemized Deductions for Individuals and Corporations § 1.162-4 Repairs. The cost of incidental repairs which neither materially add to the value of the property nor appreciably prolong its...

  9. Bringing mask repair to the next level

    NASA Astrophysics Data System (ADS)

    Edinger, K.; Wolff, K.; Steigerwald, H.; Auth, N.; Spies, P.; Oster, J.; Schneider, H.; Budach, M.; Hofmann, T.; Waiblinger, M.

    2014-10-01

    Mask repair is an essential step in the mask manufacturing process as the extension of 193nm technology and the insertion of EUV are drivers for mask complexity and cost. The ability to repair all types of defects on all mask blank materials is crucial for the economic success of a mask shop operation. In the future mask repair is facing several challenges. The mask minimum features sizes are shrinking and require a higher resolution repair tool. At the same time mask blanks with different new mask materials are introduced to optimize optical performance and long term durability. For EUV masks new classes of defects like multilayer and phase defects are entering the stage. In order to achieve a high yield, mask repair has to cover etch and deposition capabilities and must not damage the mask. These challenges require sophisticated technologies to bring mask repair to the next level. For high end masks ion-beam based and e-based repair technologies are the obvious choice when it comes to the repair of small features. Both technologies have their pro and cons. The scope of this paper is to review and compare the performance of ion-beam based mask repair to e-beam based mask repair. We will analyze the limits of both technologies theoretically and experimentally and show mask repair related performance data. Based on this data, we will give an outlook to future mask repair tools.

  10. Standardized Curriculum for Automotive Body Repair.

    ERIC Educational Resources Information Center

    Mississippi State Dept. of Education, Jackson. Office of Vocational, Technical and Adult Education.

    Standardized curricula are provided for two courses for the secondary vocational education program in Mississippi: automotive body repair I and II. The nine units in automotive body repair I are as follows: introduction; related information; basic tool usage and safety; body and frame construction; basic sheet metal repair; preparing for…

  11. Single suture customized loop for large iridodialysis repair

    PubMed Central

    Omar Yousif, Mohamed

    2016-01-01

    Managing large iridodialysis that may occur during phacoemulsification is challenging. I describe how a procedure to reposit a prolapsed iris while the anterior chamber is markedly inflated by a current of infusion fluid may inadvertently lead to large iridodialysis, and discuss how to avoid such a complication. I describe a fast and efficient technique for managing large iridodialysis both immediately, once it occurs, or as a secondary maneuver. My technique involved fixing the iris periphery back to its root at the anterior chamber angle using 10-0 polypropylene suture with two straight needles introduced directly through the cornea at distant points, and an insulin syringe as a guide track to a point 1.5 mm from the limbus at the base of a triangular scleral flap that was designed to be centered on the area of iridodialysis. I confirmed the simplicity, efficacy, and safety of my technique through a 1-year follow-up period. PMID:27729765

  12. Repair of major system elements on Skylab

    NASA Technical Reports Server (NTRS)

    Pace, R. E., Jr.

    1975-01-01

    In-flight maintenance, as conceived and pre-planned for the Skylab Mission, was limited to simple scheduled and unscheduled replacement tasks and minor contingency repairs. Failures during the mission dictated complicated and sophisticated repairs to major systems so that the mission could continue. These repairs include the release of a large structure that failed to deploy, the assembly and deployment of large mechanical devices, the installation and checkout of precision electronic equipment, troubleshooting and repair of precision electromechanical equipment and tapping into and recharging a cooling system. The Skylab experience proves conclusively that crewmen can, with adequate training, make major system repairs in space using standard or special tools.

  13. Endovascular Repair of Thoracic Aortic Aneurysms

    PubMed Central

    Findeiss, Laura K.; Cody, Michael E.

    2011-01-01

    Degenerative aneurysms of the thoracic aorta are increasing in prevalence; open repair of descending thoracic aortic aneurysms is associated with high rates of morbidity and mortality. Repair of isolated descending thoracic aortic aneurysms using stent grafts was introduced in 1995, and in an anatomically suitable subgroup of patients with thoracic aortic aneurysm, repair with endovascular stent graft provides favorable outcomes, with decreased perioperative morbidity and mortality relative to open repair. The cornerstones of successful thoracic endovascular aneurysm repair are appropriate patient selection, thorough preprocedural planning, and cautious procedural execution, the elements of which are discussed here. PMID:22379281

  14. Response of base excision repair enzymes to complex DNA lesions.

    PubMed

    Weinfeld, M; Rasouli-Nia, A; Chaudhry, M A; Britten, R A

    2001-11-01

    There is now increasing evidence that ionizing radiation generates complex DNA damage, i.e. two or more lesions--single-strand breaks or modified nucleosides--located within one to two helical turns on the same strand or on opposite strands. Double-strand breaks are the most readily recognizable clustered lesions, but they may constitute a relatively minor fraction of the total. It is anticipated that clustered lesions may play a significant role in cellular response to ionizing radiation since they may present a major challenge to the DNA repair machinery. The degree of lesion complexity increases with increasing LET. This has potential implications for space travel because of exposure to high-LET cosmic radiation. It is therefore critical that we begin to understand the consequences of such damaged sites, including their influence on DNA repair enzymes. This paper presents a short review of our current knowledge of the action of purified DNA repair enzymes belonging to the base excision repair pathway, including DNA glycosylases and apurinic/apyrimidinic endonucleases, on model complex lesions.

  15. A molecular beacon assay for measuring base excision repair activities.

    PubMed

    Maksimenko, Andrei; Ishchenko, Alexander A; Sanz, Guenhaël; Laval, Jacques; Elder, Rhoderick H; Saparbaev, Murat K

    2004-06-18

    The base excision repair (BER) pathway plays a key role in protecting the genome from endogenous DNA damage. Current methods to measure BER activities are indirect and cumbersome. Here, we introduce a direct method to assay DNA excision repair that is suitable for automation and industrial use, based on the fluorescence quenching mechanism of molecular beacons. We designed a single-stranded DNA oligonucleotide labelled with a 5'-fluorescein (F) and a 3'-Dabcyl (D) in which the fluorophore, F, is held in close proximity to the quencher, D, by the stem-loop structure design of the oligonucleotide. Following removal of the modified base or incision of the oligonucleotide, the fluorophore is separated from the quencher and fluorescence can be detected as a function of time. Several modified beacons have been used to validate the assay on both cell-free extracts and purified proteins. We have further developed the method to analyze BER in cultured cells. As described, the molecular beacon-based assay can be applied to all DNA modifications processed by DNA excision/incision repair pathways. Possible applications of the assay are discussed, including high-throughput real-time DNA repair measurements both in vitro and in living cells.

  16. Rad51 Regulates Reprogramming Efficiency through DNA Repair Pathway

    PubMed Central

    Lee, Jae-Young; Kim, Dae-Kwan; Ko, Jeong-Jae; Kim, Keun Pil; Park, Kyung-Soon

    2016-01-01

    Rad51 is a key component of homologous recombination (HR) to repair DNA double-strand breaks and it forms Rad51 recombinase filaments of broken single-stranded DNA to promote HR. In addition to its role in DNA repair and cell cycle progression, Rad51 contributes to the reprogramming process during the generation of induced pluripotent stem cells. In light of this, we performed reprogramming experiments to examine the effect of co-expression of Rad51 and four reprogramming factors, Oct4, Sox2, Klf4, and c-Myc, on the reprogramming efficiency. Co-expression of Rad51 significantly increased the numbers of alkaline phosphatase-positive colonies and embryonic stem cell-like colonies during the process of reprogramming. Co-expression ofRad51 significantly increased the expression of epithelial markers at an early stage of reprogramming compared with control cells. Phosphorylated histone H2AX (γH2AX), which initiates the DNA double-strand break repair system, was highly accumulated in reprogramming intermediates upon co-expression of Rad51. This study identified a novel role of Rad51 in enhancing the reprogramming efficiency, possibly by facilitating mesenchymal-to-epithelial transition and by regulating a DNA damage repair pathway during the early phase of the reprogramming process. PMID:27660832

  17. DNA Repair-Protein Relocalization After Heavy Ion Exposure

    NASA Technical Reports Server (NTRS)

    Metting, N. F.

    1999-01-01

    Ionizing radiation is good at making DNA double strand breaks, and high linear energy transfer (LET) radiations such as heavy ion particles are particularly efficient. For this reason, the proteins belonging to repair systems that deal with double strand breaks are of particular interest. One such protein is Ku, a component in the non-homologous recombination repair system. The Ku protein is an abundant, heterodimeric DNA end-binding complex, composed of one 70 and one 86 kDa subunit. Ku protein binds to DNA ends, nicks, gaps, and regions of transition between single and double-stranded structure. These binding properties suggest an important role in DNA repair. The Ku antigen is important in this study because it is present in relatively large copy numbers and it is part of a double-strand-break repair system. More importantly, we consistently measure an apparent upregulation in situ that is not verified by whole-cell-lysate immunoblot measurements. This apparent upregulation is triggered by very low doses of radiation, thus showing a potentially useful high sensitivity. However, elucidation of the mechanism underlying this phenomenon is still to be done.

  18. Rad51 Regulates Reprogramming Efficiency through DNA Repair Pathway.

    PubMed

    Lee, Jae-Young; Kim, Dae-Kwan; Ko, Jeong-Jae; Kim, Keun Pil; Park, Kyung-Soon

    2016-06-01

    Rad51 is a key component of homologous recombination (HR) to repair DNA double-strand breaks and it forms Rad51 recombinase filaments of broken single-stranded DNA to promote HR. In addition to its role in DNA repair and cell cycle progression, Rad51 contributes to the reprogramming process during the generation of induced pluripotent stem cells. In light of this, we performed reprogramming experiments to examine the effect of co-expression of Rad51 and four reprogramming factors, Oct4, Sox2, Klf4, and c-Myc, on the reprogramming efficiency. Co-expression of Rad51 significantly increased the numbers of alkaline phosphatase-positive colonies and embryonic stem cell-like colonies during the process of reprogramming. Co-expression ofRad51 significantly increased the expression of epithelial markers at an early stage of reprogramming compared with control cells. Phosphorylated histone H2AX (γH2AX), which initiates the DNA double-strand break repair system, was highly accumulated in reprogramming intermediates upon co-expression of Rad51. This study identified a novel role of Rad51 in enhancing the reprogramming efficiency, possibly by facilitating mesenchymal-to-epithelial transition and by regulating a DNA damage repair pathway during the early phase of the reprogramming process. PMID:27660832

  19. 40 CFR 798.5500 - Differential growth inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... recommendations as specified under 40 CFR part 792, subpart J the following specific information should be... repair proficient and repair deficient bacteria: âBacterial DNA damage or repair tests.â 798.5500 Section... inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA damage or repair tests.”...

  20. 40 CFR 798.5500 - Differential growth inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... recommendations as specified under 40 CFR part 792, subpart J the following specific information should be... repair proficient and repair deficient bacteria: âBacterial DNA damage or repair tests.â 798.5500 Section... inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA damage or repair tests.”...

  1. 40 CFR 798.5500 - Differential growth inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... recommendations as specified under 40 CFR part 792, subpart J the following specific information should be... repair proficient and repair deficient bacteria: âBacterial DNA damage or repair tests.â 798.5500 Section... inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA damage or repair tests.”...

  2. 40 CFR 798.5500 - Differential growth inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... recommendations as specified under 40 CFR part 792, subpart J the following specific information should be... repair proficient and repair deficient bacteria: âBacterial DNA damage or repair tests.â 798.5500 Section... inhibition of repair proficient and repair deficient bacteria: “Bacterial DNA damage or repair tests.”...

  3. Shuttle orbiter TPS flight repair kit development

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The design and application of a TPS repair kit is presented. The repair kit is designed for on orbit use by a crew member working in the manned maneuvering unit (MMU). The kit includes the necessary equipment and materials to accomplish the repair tasks which include the following: HRSI emittance coating repair, damaged tile repair, missing tile repair, and multiple tile repair. Two types of repair materials required to do the small area repair and the large area repair are described. The materials area cure in place, silicone base ablator for small damaged areas and precured ablator tile for repair of larger damaged areas is examined. The cure in place ablator is also used as an adhesive to bond the precured tiles in place. An applicator for the cure in place ablator, designed to contain a two-part silicon compound, mix the two components at correct ratio, and dispense the materials at rates compatible with mission timelines established for the EVA is described.

  4. Ultrasound determination of rotator cuff tear repairability

    PubMed Central

    Tse, Andrew K; Lam, Patrick H; Walton, Judie R; Hackett, Lisa

    2015-01-01

    Background Rotator cuff repair aims to reattach the torn tendon to the greater tuberosity footprint with suture anchors. The present study aimed to assess the diagnostic accuracy of ultrasound in predicting rotator cuff tear repairability and to assess which sonographic and pre-operative features are strongest in predicting repairability. Methods The study was a retrospective analysis of measurements made prospectively in a cohort of 373 patients who had ultrasounds of their shoulder and underwent rotator cuff repair. Measurements of rotator cuff tear size and muscle atrophy were made pre-operatively by ultrasound to enable prediction of rotator cuff repairability. Tears were classified following ultrasound as repairable or irreparable, and were correlated with intra-operative repairability. Results Ultrasound assessment of rotator cuff tear repairability has a sensitivity of 86% (p < 0.0001) and a specificity of 67% (p < 0.0001). The strongest predictors of rotator cuff repairability were tear size (p < 0.001) and age (p = 0.004). Sonographic assessments of tear size ≥4 cm2 or anteroposterior tear length ≥25 mm indicated an irreparable rotator cuff tear. Conclusions Ultrasound assessment is accurate in predicting rotator cuff tear repairability. Tear size or anteroposterior tear length and age were the best predictors of repairability. PMID:27582996

  5. Repair of parastomal hernias using polypropylene mesh.

    PubMed

    Byers, J M; Steinberg, J B; Postier, R G

    1992-10-01

    Parastomal hernias are a common complication of ostomy construction. We have developed a method of repair that uses two strips of polypropylene prosthetic mesh through a midline incision. The medical records of 19 patients who underwent parastomal hernia repair were retrospectively reviewed. All nine patients operated on for this condition by the senior author (R.G.P.) (group 1) underwent repairs with this technique. All ten patients operated on by other surgeons in our center (group 2) underwent repairs in which the stoma was moved, the fascia was directly repaired through a parastomal incision, or the fascia was repaired via a midline incision. No patients in group 1 had recurrences while five patients in group 2 had recurrences. Neither group developed strictures or stomal prolapse. Our method of repair is technically easy and has excellent results. It is especially suitable in very large hernias in which incisional hernia is likely in the original stoma site if the stoma is moved. PMID:1417494

  6. Minimally disruptive schedule repair for MCM missions

    NASA Astrophysics Data System (ADS)

    Molineaux, Matthew; Auslander, Bryan; Moore, Philip G.; Gupta, Kalyan M.

    2015-05-01

    Mine countermeasures (MCM) missions entail planning and operations in very dynamic and uncertain operating environments, which pose considerable risk to personnel and equipment. Frequent schedule repairs are needed that consider the latest operating conditions to keep mission on target. Presently no decision support tools are available for the challenging task of MCM mission rescheduling. To address this capability gap, we have developed the CARPE system to assist operation planners. CARPE constantly monitors the operational environment for changes and recommends alternative repaired schedules in response. It includes a novel schedule repair algorithm called Case-Based Local Schedule Repair (CLOSR) that automatically repairs broken schedules while satisfying the requirement of minimal operational disruption. It uses a case-based approach to represent repair strategies and apply them to new situations. Evaluation of CLOSR on simulated MCM operations demonstrates the effectiveness of case-based strategy. Schedule repairs are generated rapidly, ensure the elimination of all mines, and achieve required levels of clearance.

  7. Proliferation during early phases of bronchiolar repair in neonatal rabbits following lung injury by 4-ipomeanol.

    PubMed

    Smiley-Jewell, Suzette M; Plopper, Charles G

    2003-10-01

    Nonciliated bronchiolar (Clara cells) are progenitor cells during development. During differentiation, they are more susceptible to injury by environmental toxicants metabolized by the cytochrome P450 monooxygenase system, and injury results in altered bronchiolar repair and development. Squamous cells and abnormal cuboidal epithelium persist into early adulthood. The hypothesis tested in this study was that the failure of bronchiolar epithelium to repair normally in neonates following injury is due to an inhibition of proliferation. A model of differential repair in rabbit kits was used. Proliferation was followed for 1 week post injury in rabbit kits treated with a single dose of the P450-mediated cytotoxicant 4-ipomeanol (IPO) at 7 days old (repair abnormal) and compared to rabbits treated with a single dose of IPO at 21 days old (repair normal). Proliferation was measured by the nuclear incorporation of 5-chloro-2'-deoxyuridine (CldU) within epithelium at the target site (terminal bronchiole). The repair pattern between the two age groups was histologically defined. There was no difference in the CldU labeling index during the week of repair between the two age groups, even though the bronchiolar epithelium did not return to normal in the animals treated at 7 days old. In summary, proliferation (through S-phase) is not inhibited during repair in neonatal rabbits treated with IPO at 7 days old compared to animals treated at 21 days old, and we conclude that other factors may be responsible for the altered repair in the young neonates injured by a P450-mediated cytotoxicant. PMID:14554104

  8. Lambda Red Mediated Gap Repair Utilizes a Novel Replicative Intermediate in Escherichia coli

    PubMed Central

    Reddy, Thimma R.; Fevat, Léna M. S.; Munson, Sarah E.; Stewart, A. Francis; Cowley, Shaun M.

    2015-01-01

    The lambda phage Red recombination system can mediate efficient homologous recombination in Escherichia coli, which is the basis of the DNA engineering technique termed recombineering. Red mediated insertion of DNA requires DNA replication, involves a single-stranded DNA intermediate and is more efficient on the lagging strand of the replication fork. Lagging strand recombination has also been postulated to explain the Red mediated repair of gapped plasmids by an Okazaki fragment gap filling model. Here, we demonstrate that gap repair involves a different strand independent mechanism. Gap repair assays examining the strand asymmetry of recombination did not show a lagging strand bias. Directly testing an ssDNA plasmid showed lagging strand recombination is possible but dsDNA plasmids did not employ this mechanism. Insertional recombination combined with gap repair also did not demonstrate preferential lagging strand bias, supporting a different gap repair mechanism. The predominant recombination route involved concerted insertion and subcloning though other routes also operated at lower frequencies. Simultaneous insertion of DNA resulted in modification of both strands and was unaffected by mutations to DNA polymerase I, responsible for Okazaki fragment maturation. The lower efficiency of an alternate Red mediated ends-in recombination pathway and the apparent lack of a Holliday junction intermediate suggested that gap repair does not involve a different Red recombination pathway. Our results may be explained by a novel replicative intermediate in gap repair that does not involve a replication fork. We exploited these observations by developing a new recombineering application based on concerted insertion and gap repair, termed SPI (subcloning plus insertion). SPI selected against empty vector background and selected for correct gap repair recombinants. We used SPI to simultaneously insert up to four different gene cassettes in a single recombineering reaction

  9. Escherichia Coli Mutator Mutd5 Is Defective in the Muthls Pathway of DNA Mismatch Repair

    PubMed Central

    Schaaper, R. M.

    1989-01-01

    We have previously reported that the Escherichia coli mutator strain mutD5 was defective in the correction of bacteriophage M13mp2 heteroduplex DNA containing a T·G mismatch. Here, this defect was further investigated with regard to its interaction with the mutHLS pathway of mismatch repair. A set of 15 different M13mp2 heteroduplexes was used to measure the mismatch-repair capability of wild-type, mutL and mutD5 cells. Throughout the series, the mutD5 strain proved as deficient in mismatch repair as the mutL strain, indicating that the repair defect is similar in the two strains in both extent and specificity. [One exception was noted in the case of a T·G mispair that was subject to VSP (Very Short Patch) repair. VSP repair was abolished by mutL but not by mutD.] Variation in the dam-methylation state of the heteroduplex molecules clearly affected repair in the wild-type strain but had no effect on either the mutD or mutL strain. Finally, mutDmutL or mutDmutS double-mutator strains were no more deficient in mismatch repair as were the single mutator strains. The combined results strongly argue that the mismatch-repair deficiency of mutD5 cells resides in the mutH,L,S-dependent pathway of mismatch repair and that the high mutation rate of mutD strains derives in part from this defect. PMID:2659431

  10. Methods of repairing a substrate

    NASA Technical Reports Server (NTRS)

    Riedell, James A. (Inventor); Easler, Timothy E. (Inventor)

    2011-01-01

    A precursor of a ceramic adhesive suitable for use in a vacuum, thermal, and microgravity environment. The precursor of the ceramic adhesive includes a silicon-based, preceramic polymer and at least one ceramic powder selected from the group consisting of aluminum oxide, aluminum nitride, boron carbide, boron oxide, boron nitride, hafnium boride, hafnium carbide, hafnium oxide, lithium aluminate, molybdenum silicide, niobium carbide, niobium nitride, silicon boride, silicon carbide, silicon oxide, silicon nitride, tin oxide, tantalum boride, tantalum carbide, tantalum oxide, tantalum nitride, titanium boride, titanium carbide, titanium oxide, titanium nitride, yttrium oxide, zirconium boride, zirconium carbide, zirconium oxide, and zirconium silicate. Methods of forming the ceramic adhesive and of repairing a substrate in a vacuum and microgravity environment are also disclosed, as is a substrate repaired with the ceramic adhesive.

  11. Primary unilateral cleft lip repair

    PubMed Central

    Adenwalla, H. S.; Narayanan, P. V.

    2009-01-01

    The unilateral cleft lip is a complex deformity. Surgical correction has evolved from a straight repair through triangular and quadrilateral repairs to the Rotation Advancement Technique of Millard. The latter is the technique followed at our centre for all unilateral cleft lip patients. We operate on these at five to six months of age, do not use pre-surgical orthodontics, and follow a protocol to produce a notch-free vermillion. This is easy to follow even for trainees. We also perform closed alar dissection and extensive primary septoplasty in all these patients. This has improved the overall result and has no long-term deleterious effect on the growth of the nose or of the maxilla. Other refinements have been used for prevention of a high-riding nostril, and correction of the vestibular web. PMID:19884683

  12. How to Relate Complex DNA Repair Genotypes to Pathway Function and, Ultimately, Health Risk

    SciTech Connect

    Jones, IM

    2002-01-09

    Exposure to ionizing radiation increases the incidence of cancer. However, predicting which individuals are at most risk from radiation exposure is a distant goal. Predictive ability is needed to guide policies that regulate radiation exposure and ensure that medical treatments have maximum benefit and minimum risk. Differences between people in susceptibility to radiation are largely based on their genotype, the genes inherited from their parents. Among the important genes are those that produce proteins that repair DNA damaged by radiation. Base Excision Repair (BER) proteins repair single strand breaks and oxidized bases in DNA. Double Strand Break Repair proteins repair broken chromosomes. Using technologies and information from the Human Genome Project, we have previously determined that the DNA sequence of DNA repair genes varies within the human population. An average of 3-4 different variants were found that affect the protein for each of 37 genes studied. The average frequency of these variants is 5%. Given the many genes in each DNA repair pathway and their many variants, technical ability to determine an individual's repair genotype greatly exceeds ability to interpret the information. A long-term goal is to relate DNA repair genotypes to health risk from radiation. This study focused on the BER pathway. The BER genes are known, variants of the genes have been identified at LLNL, and LLNL had recently developed an assay for BER function using white blood cells. The goal of this initial effort was to begin developing data that could be used to test the hypothesis that many different genotypes have similar DNA repair capacity phenotypes (function). Relationships between genotype and phenotype could then be used to group genotypes with similar function and ultimately test the association of groups of genotypes with health risk from radiation. Genotypes with reduced repair function are expected to increase risk of radiation-induced health effects. The goal

  13. Which mesh for hernia repair?

    PubMed Central

    Brown, CN; Finch, JG

    2010-01-01

    INTRODUCTION The concept of using a mesh to repair hernias was introduced over 50 years ago. Mesh repair is now standard in most countries and widely accepted as superior to primary suture repair. As a result, there has been a rapid growth in the variety of meshes available and choosing the appropriate one can be difficult. This article outlines the general properties of meshes and factors to be considered when selecting one. MATERIALS AND METHODS We performed a search of the medical literature from 1950 to 1 May 2009, as indexed by Medline, using the PubMed search engine (). To capture all potentially relevant articles with the highest degree of sensitivity, the search terms were intentionally broad. We used the following terms: ‘mesh, pore size, strength, recurrence, complications, lightweight, properties’. We also hand-searched the bibliographies of relevant articles and product literature to identify additional pertinent reports. RESULTS AND CONCLUSIONS The most important properties of meshes were found to be the type of filament, tensile strength and porosity. These determine the weight of the mesh and its biocompatibility. The tensile strength required is much less than originally presumed and light-weight meshes are thought to be superior due to their increased flexibility and reduction in discomfort. Large pores are also associated with a reduced risk of infection and shrinkage. For meshes placed in the peritoneal cavity, consideration should also be given to the risk of adhesion formation. A variety of composite meshes have been promoted to address this, but none appears superior to the others. Finally, biomaterials such as acellular dermis have a place for use in infected fields but have yet to prove their worth in routine hernia repair. PMID:20501011

  14. Cell therapy for bone repair.

    PubMed

    Rosset, P; Deschaseaux, F; Layrolle, P

    2014-02-01

    When natural bone repair mechanisms fail, autologous bone grafting is the current standard of care. The osteogenic cells and bone matrix in the graft provide the osteo-inductive and osteo-conductive properties required for successful bone repair. Bone marrow (BM) mesenchymal stem cells (MSCs) can differentiate into osteogenic cells. MSC-based cell therapy holds promise for promoting bone repair. The amount of MSCs available from iliac-crest aspirates is too small to be clinically useful, and either concentration or culture must therefore be used to expand the MSC population. MSCs can be administered alone via percutaneous injection or implanted during open surgery with a biomaterial, usually biphasic hydroxyapatite/β-calcium-triphosphate granules. Encouraging preliminary results have been obtained in patients with delayed healing of long bone fractures or avascular necrosis of the femoral head. Bone tissue engineering involves in vitro MSC culturing on biomaterials to obtain colonisation of the biomaterial and differentiation of the cells. The biomaterial-cell construct is then implanted into the zone to be treated. Few published data are available on bone tissue engineering. Much work remains to be done before determining whether this method is suitable for the routine filling of bone tissue defects. Increasing cell survival and promoting implant vascularisation are major challenges. Improved expertise with culturing techniques, together with the incorporation of regulatory requirements, will open the way to high-quality clinical trials investigating the usefulness of cell therapy as a method for achieving bone repair. Cell therapy avoids the drawbacks of autologous bone grafting, preserving the bone stock and diminishing treatment invasiveness.

  15. Wnt Signaling and Injury Repair

    PubMed Central

    Whyte, Jemima L.; Smith, Andrew A.; Helms, Jill A.

    2012-01-01

    Wnt signaling is activated by wounding and participates in every subsequent stage of the healing process from the control of inflammation and programmed cell death, to the mobilization of stem cell reservoirs within the wound site. In this review we summarize recent data elucidating the roles that the Wnt pathway plays in the injury repair process. These data provide a foundation for potential Wnt-based therapeutic strategies aimed at stimulating tissue regeneration. PMID:22723493

  16. Calcium signaling in membrane repair

    PubMed Central

    Cheng, Xiping; Zhang, Xiaoli; Yu, Lu; Xu, Haoxing

    2015-01-01

    Resealing allows cells to mend damaged membranes rapidly when plasma membrane (PM) disruptions occur. Models of PM repair mechanisms include the “lipid-patch”, “endocytic removal”, and “macro-vesicle shedding” models, all of which postulate a dependence on local increases in intracellular Ca2+ at injury sites. Multiple calcium sensors, including synaptotagmin (Syt) VII, dysferlin, and apoptosis-linked gene-2 (ALG-2), are involved in PM resealing, suggesting that Ca2+ may regulate multiple steps of the repair process. Although earlier studies focused exclusively on external Ca2+, recent studies suggest that Ca2+ release from intracellular stores may also be important for PM resealing. Hence, depending on injury size and the type of injury, multiple sources of Ca2+ may be recruited to trigger and orchestrate repair processes. In this review, we discuss the mechanisms by which the resealing process is promoted by vesicular Ca2+ channels and Ca2+ sensors that accumulate at damage sites. PMID:26519113

  17. Role of biomechanics on intervertebral disc degeneration and regenerative therapies: What needs repairing in the disc and what are promising biomaterials for its repair?

    PubMed Central

    Iatridis, James C.; Nicoll, Steven B.; Michalek, Arthur J.; Walter, Benjamin A.; Gupta, Michelle S.

    2013-01-01

    , fibrous composites, and sealants offer promise for regenerative therapies to restore AF integrity. Tissue engineered intervertebral disc structures, as a single implantable construct, may promote greater tissue integration due to improved repair capacity of vertebral bone. Conclusions Intervertebral disc height, neutral zone characteristics and torsional biomechanics are sensitive to specific alterations in nucleus pulposus pressurization and annulus fibrosus integrity, and must be addressed for effective functional repair. Synthetic and natural biomaterials offer promise for NP replacement, AF repair, as an AF sealant, or for whole disc replacement. Meeting mechanical as well as biological compatibility is necessary for the efficacy and longevity of the repair. PMID:23369494

  18. Strategies for Controlled Delivery of Biologics for Cartilage Repair

    PubMed Central

    Lam, Johnny; Lu, Steven; Kasper, F. Kurtis; Mikos, Antonios G.

    2014-01-01

    The delivery of biologics is an important component in the treatment of osteoarthritis and the functional restoration of articular cartilage. Numerous factors have been implicated in the cartilage repair process, but the uncontrolled delivery of these factors may not only reduce their full reparative potential and can also cause unwanted morphological effects. It is therefore imperative to consider the type of biologic to be delivered, the method of delivery, and the temporal as well as spatial presentation of the biologic to achieve the desired effect in cartilage repair. Additionally, the delivery of a single factor may not be sufficient in guiding neo-tissue formation, motivating recent research towards the delivery of multiple factors. This review will discuss the roles of various biologics involved in cartilage repair and the different methods of delivery for appropriate healing responses. A number of spatiotemporal strategies will then be emphasized for the controlled delivery of single and multiple bioactive factors in both in vitro and in vivo cartilage tissue engineering applications. PMID:24993610

  19. Bond strength of repaired amalgam restorations.

    PubMed

    Rey, Rosalia; Mondragon, Eduardo; Shen, Chiayi

    2015-01-01

    This in vitro study investigated the interfacial flexural strength (FS) of amalgam repairs and the optimal combination of repair materials and mechanical retention required for a consistent and durable repair bond. Amalgam bricks were created, each with 1 end roughened to expose a fresh surface before repair. Four groups followed separate repair protocols: group 1, bonding agent with amalgam; group 2, bonding agent with composite resin; group 3, mechanical retention (slot) with amalgam; and group 4, slot with bonding agent and amalgam. Repaired specimens were stored in artificial saliva for 1, 10, 30, 120, or 360 days before being loaded to failure in a 3-point bending test. Statistical analysis showed significant changes in median FS over time in groups 2 and 4. The effect of the repair method on the FS values after each storage period was significant for most groups except the 30-day storage groups. Amalgam-amalgam repair with adequate condensation yielded the most consistent and durable bond. An amalgam bonding agent could be beneficial when firm condensation on the repair surface cannot be achieved or when tooth structure is involved. Composite resin can be a viable option for amalgam repair in an esthetically demanding region, but proper mechanical modification of the amalgam surface and selection of the proper bonding system are essential.

  20. Bond strength of repaired amalgam restorations.

    PubMed

    Rey, Rosalia; Mondragon, Eduardo; Shen, Chiayi

    2015-01-01

    This in vitro study investigated the interfacial flexural strength (FS) of amalgam repairs and the optimal combination of repair materials and mechanical retention required for a consistent and durable repair bond. Amalgam bricks were created, each with 1 end roughened to expose a fresh surface before repair. Four groups followed separate repair protocols: group 1, bonding agent with amalgam; group 2, bonding agent with composite resin; group 3, mechanical retention (slot) with amalgam; and group 4, slot with bonding agent and amalgam. Repaired specimens were stored in artificial saliva for 1, 10, 30, 120, or 360 days before being loaded to failure in a 3-point bending test. Statistical analysis showed significant changes in median FS over time in groups 2 and 4. The effect of the repair method on the FS values after each storage period was significant for most groups except the 30-day storage groups. Amalgam-amalgam repair with adequate condensation yielded the most consistent and durable bond. An amalgam bonding agent could be beneficial when firm condensation on the repair surface cannot be achieved or when tooth structure is involved. Composite resin can be a viable option for amalgam repair in an esthetically demanding region, but proper mechanical modification of the amalgam surface and selection of the proper bonding system are essential. PMID:26325656

  1. [Mechanisms of repair after renal injury].

    PubMed

    Menè, P; Polci, R; Festuccia, F

    2003-01-01

    Recovery from kidney injury through repair mechanisms often linked to inflammation is conditioned by nature and severity of the insult. In the assessment of kidney repair, functional recovery should be kept distinct from structural repair: compensatory hypertrophy/function of intact nephrons often masks the inability of the kidney to heal or replace damaged structures. The mechanisms of repair reflect three degrees of injury, differently handled by the kidney. First, repair of DNA damage is accomplished through proofreading DNA polymerases, along with other controls for sequence misalignment / nucleotide replacement. If DNA cannot be repaired, cells carrying mutation(s) are disposed of through apoptosis, which is also critical to clearing damaged kidney cells and infiltrating leukocytes in acute and chronic ischemic, immunological, or chemical damage. A second mechanism of repair is linked to proliferation of surviving cells. At least 5 types of reparative proliferation are known to occur, some of which implicate stem cell immigration from distant reservoirs, followed by in situ differentiation. A third mode of repair could be referred to as structural repair, indeed limited in the human kidney by the absence of postnatal nephrogenesis. Recovery from acute tubular necrosis involves remodelling of the proximal tubule, with a strict requirement for integrity of the basement membrane. Contrary to the current dogma that only acute injury can be repaired, whereas chronic damage leads to irreversible loss of nephrons, evidence is emerging that some degree of renal remodelling occurs even in chronic renal disease, despite the occurrence of stabilized structural changes.

  2. PARP-1 and Ku compete for repair of DNA double strand breaks by distinct NHEJ pathways

    PubMed Central

    Wang, Minli; Wu, Weizhong; Wu, Wenqi; Rosidi, Bustanur; Zhang, Lihua; Wang, Huichen; Iliakis, George

    2006-01-01

    Poly(ADP-ribose)polymerase 1 (PARP-1) recognizes DNA strand interruptions in vivo and triggers its own modification as well as that of other proteins by the sequential addition of ADP-ribose to form polymers. This modification causes a release of PARP-1 from DNA ends and initiates a variety of responses including DNA repair. While PARP-1 has been firmly implicated in base excision and single strand break repair, its role in the repair of DNA double strand breaks (DSBs) remains unclear. Here, we show that PARP-1, probably together with DNA ligase III, operates in an alternative pathway of non-homologous end joining (NHEJ) that functions as backup to the classical pathway of NHEJ that utilizes DNA-PKcs, Ku, DNA ligase IV, XRCC4, XLF/Cernunnos and Artemis. PARP-1 binds to DNA ends in direct competition with Ku. However, in irradiated cells the higher affinity of Ku for DSBs and an excessive number of other forms of competing DNA lesions limit its contribution to DSB repair. When essential components of the classical pathway of NHEJ are absent, PARP-1 is recruited for DSB repair, particularly in the absence of Ku and non-DSB lesions. This form of DSB repair is sensitive to PARP-1 inhibitors. The results define the function of PARP-1 in DSB repair and characterize a candidate pathway responsible for joining errors causing genomic instability and cancer. PMID:17088286

  3. The nuclease FAN1 is involved in DNA crosslink repair in Arabidopsis thaliana independently of the nuclease MUS81

    PubMed Central

    Herrmann, Natalie J.; Knoll, Alexander; Puchta, Holger

    2015-01-01

    Fanconi anemia is a severe genetic disorder. Mutations in one of several genes lead to defects in DNA crosslink (CL) repair in human cells. An essential step in CL repair is the activation of the pathway by the monoubiquitination of the heterodimer FANCD2/FANCI, which recruits the nuclease FAN1 to the CL site. Surprisingly, FAN1 function is not conserved between different eukaryotes. No FAN1 homolog is present in Drosophila and Saccharomyces cerevisiae. The FAN1 homolog in Schizosaccharomyces pombe is involved in CL repair; a homolog is present in Xenopus but is not involved in CL repair. Here we show that a FAN1 homolog is present in plants and it is involved in CL repair in Arabidopsis thaliana. Both the virus-type replication-repair nuclease and the ubiquitin-binding ubiquitin-binding zinc finger domains are essential for this function. FAN1 likely acts upstream of two sub-pathways of CL repair. These pathways are defined by the Bloom syndrome homolog RECQ4A and the ATPase RAD5A, which is involved in error-free post-replicative repair. Mutations in both FAN1 and the endonuclease MUS81 resulted in greater sensitivity against CLs than in the respective single mutants. These results indicate that the two nucleases define two independent pathways of CL repair in plants. PMID:25779053

  4. Fine-mapping of DNA damage and repair in specific genomic segments.

    PubMed Central

    Govan, H L; Valles-Ayoub, Y; Braun, J

    1990-01-01

    The susceptibility of various genomic regions to DNA damage and repair is heterogeneous. While this can be related to factors such as primary sequence, physical conformation, and functional status, the exact mechanisms involved remain unclear. To more precisely define the key features of a genomic region targeted for these processes, a useful tool would be a method for fine-mapping gene-specific DNA damage and repair in vivo. Here, a polymerase chain reaction-based assay is described for measuring DNA damage and repair in small (less than 500 bp) genomic segments of three transcriptionally active but functionally distinct loci (rearranged immunoglobulin heavy chain variable region [Ig VDJ], low-density lipoprotein receptor gene, and N-ras proto-oncogene) in human tonsillar B lymphocytes. Analysis of ultraviolet (254 nm)-induced DNA damage revealed single-hit kinetics and a similar level of sensitivity (D50% approximately 6000 joule/m2) in all three regions, indicating that a single photoproduct was sufficient to fully block PCR amplification. A similar time period per unit length was required for repair of this DNA damage (average t1/2 per fragment length = 23.5 seconds per bp). DNA damage and repair was also detectable with the base adducting agent, 4-nitroquinoline-1-oxide. However, in this case IgVDJ differed from segments within the other two loci by its relative inaccessibility to alkylation. This assay thus permits high-resolution mapping of DNA damage and repair activity. Images PMID:2115669

  5. Disruption of microtubule integrity initiates mitosis during CNS repair.

    PubMed

    Bossing, Torsten; Barros, Claudia S; Fischer, Bettina; Russell, Steven; Shepherd, David

    2012-08-14

    Mechanisms of CNS repair have vital medical implications. We show that traumatic injury to the ventral midline of the embryonic Drosophila CNS activates cell divisions to replace lost cells. A pilot screen analyzing transcriptomes of single cells during repair pointed to downregulation of the microtubule-stabilizing GTPase mitochondrial Rho (Miro) and upregulation of the Jun transcription factor Jun-related antigen (Jra). Ectopic Miro expression can prevent midline divisions after damage, whereas Miro depletion destabilizes cortical β-tubulin and increases divisions. Disruption of cortical microtubules, either by chemical depolymerization or by overexpression of monomeric tubulin, triggers ectopic mitosis in the midline and induces Jra expression. Conversely, loss of Jra renders midline cells unable to replace damaged siblings. Our data indicate that upon injury, the integrity of the microtubule cytoskeleton controls cell division in the CNS midline, triggering extra mitosis to replace lost cells. The conservation of the identified molecules suggests that similar mechanisms may operate in vertebrates.

  6. Distal Triceps Knotless Anatomic Footprint Repair: A New Technique

    PubMed Central

    Paci, James M.; Clark, Jonathan; Rizzi, Angelo

    2014-01-01

    Distal triceps rupture is a rare injury causing significant disability. Several techniques for treating distal triceps ruptures have been described using bone tunnels or suture anchors. More recent techniques have focused on re-creating the anatomic footprint of the distal triceps tendon. However, the increasing numbers of anchors used increase the risk to the articular surface, and all earlier techniques require knot tying and bulky knots beneath the thin posterior elbow soft-tissue envelope. We describe a technique combining the use of bone tunnels and a single suture anchor to create a knotless anatomic footprint repair of the distal triceps. By using this technique, we are able to create a tension-band construct that self-reinforces the anatomic repair and is very low profile while significantly decreasing risk to the articular surface. PMID:25473618

  7. DNA Repair at Telomeres: Keeping the Ends Intact

    PubMed Central

    Webb, Christopher J.; Wu, Yun; Zakian, Virginia A.

    2013-01-01

    The molecular era of telomere biology began with the discovery that telomeres usually consist of G-rich simple repeats and end with 3′ single-stranded tails. Enormous progress has been made in identifying the mechanisms that maintain and replenish telomeric DNA and the proteins that protect them from degradation, fusions, and checkpoint activation. Although telomeres in different organisms (or even in the same organism under different conditions) are maintained by different mechanisms, the disparate processes have the common goals of repairing defects caused by semiconservative replication through G-rich DNA, countering the shortening caused by incomplete replication, and postreplication regeneration of G tails. In addition, standard DNA repair mechanisms must be suppressed or modified at telomeres to prevent their being recognized and processed as DNA double-strand breaks. Here, we discuss the players and processes that maintain and regenerate telomere structure. PMID:23732473

  8. Disruption of Microtubule Integrity Initiates Mitosis during CNS Repair

    PubMed Central

    Bossing, Torsten; Barros, Claudia S.; Fischer, Bettina; Russell, Steven; Shepherd, David

    2012-01-01

    Summary Mechanisms of CNS repair have vital medical implications. We show that traumatic injury to the ventral midline of the embryonic Drosophila CNS activates cell divisions to replace lost cells. A pilot screen analyzing transcriptomes of single cells during repair pointed to downregulation of the microtubule-stabilizing GTPase mitochondrial Rho (Miro) and upregulation of the Jun transcription factor Jun-related antigen (Jra). Ectopic Miro expression can prevent midline divisions after damage, whereas Miro depletion destabilizes cortical β-tubulin and increases divisions. Disruption of cortical microtubules, either by chemical depolymerization or by overexpression of monomeric tubulin, triggers ectopic mitosis in the midline and induces Jra expression. Conversely, loss of Jra renders midline cells unable to replace damaged siblings. Our data indicate that upon injury, the integrity of the microtubule cytoskeleton controls cell division in the CNS midline, triggering extra mitosis to replace lost cells. The conservation of the identified molecules suggests that similar mechanisms may operate in vertebrates. PMID:22841498

  9. Development and validation of bonded composite doubler repairs for commercial aircraft.

    SciTech Connect

    Roach, Dennis Patrick; Rackow, Kirk A.

    2007-07-01

    A typical aircraft can experience over 2,000 fatigue cycles (cabin pressurizations) and even greater flight hours in a single year. An unavoidable by-product of aircraft use is that crack, impact, and corrosion flaws develop throughout the aircraft's skin and substructure elements. Economic barriers to the purchase of new aircraft have placed even greater demands on efficient and safe repair methods. The use of bonded composite doublers offers the airframe manufacturers and aircraft maintenance facilities a cost effective method to safely extend the lives of their aircraft. Instead of riveting multiple steel or aluminum plates to facilitate an aircraft repair, it is now possible to bond a single Boron-Epoxy composite doubler to the damaged structure. The FAA's Airworthiness Assurance Center at Sandia National Labs (AANC), Boeing, and Federal Express completed a pilot program to validate and introduce composite doubler repair technology to the U.S. commercial aircraft industry. This project focused on repair of DC-10 fuselage structure and its primary goal was to demonstrate routine use of this repair technology using niche applications that streamline the design-to-installation process. As composite doubler repairs gradually appear in the commercial aircraft arena, successful flight operation data is being accumulated. These commercial aircraft repairs are not only demonstrating the engineering and economic advantages of composite doubler technology but they are also establishing the ability of commercial maintenance depots to safely adopt this repair technique. This report presents the array of engineering activities that were completed in order to make this technology available for widespread commercial aircraft use. Focused laboratory testing was conducted to compliment the field data and to address specific issues regarding damage tolerance and flaw growth in composite doubler repairs. Fatigue and strength tests were performed on a simulated wing repair using a

  10. Successful repair of injury to the eyelid, lacrimal passage, and extraocular muscle

    PubMed Central

    Shah, Shreya Mehul; Shah, Mehul Ashvin; Shah, Prerna D.; Patel, Kashyap B.

    2016-01-01

    Introduction: Injury is a known cause of monocular blindness. Ocular trauma may affect lacrimal canaliculi and the extraocular muscle. We report this case as it includes injury to lid, lacrimal canaliculi and inferior rectus. Case description: A 25-year-old male presented with an injury caused by a sharp object that resulted in a conjunctival tear, lid tear involving the lacrimal canal, and rupture of the inferior rectus muscle. All of the structures were repaired successfully during a single procedure. Conclusion: An extraocular injury involving the conjunctiva, lid, lacrimal passages, and extraocular muscles can be repaired successfully during a single procedure. PMID:27625963

  11. Successful repair of injury to the eyelid, lacrimal passage, and extraocular muscle

    PubMed Central

    Shah, Shreya Mehul; Shah, Mehul Ashvin; Shah, Prerna D.; Patel, Kashyap B.

    2016-01-01

    Introduction: Injury is a known cause of monocular blindness. Ocular trauma may affect lacrimal canaliculi and the extraocular muscle. We report this case as it includes injury to lid, lacrimal canaliculi and inferior rectus. Case description: A 25-year-old male presented with an injury caused by a sharp object that resulted in a conjunctival tear, lid tear involving the lacrimal canal, and rupture of the inferior rectus muscle. All of the structures were repaired successfully during a single procedure. Conclusion: An extraocular injury involving the conjunctiva, lid, lacrimal passages, and extraocular muscles can be repaired successfully during a single procedure.

  12. Thermal protection system repair kit program

    NASA Technical Reports Server (NTRS)

    1979-01-01

    The feasibility and conceptual design aspects of repair materials and procedures for in orbit repair of the space shuttle orbiter TPS tiles are investigated. Material studies to investigate cure in place materials are described including catalyst and cure studies, ablation tests and evaluations, and support mixing and applicator design. The feasibility of the repair procedures, the storage of the TPS, dispensing, and cure problems are addressed.

  13. Cellular repair/misrepair track model

    NASA Technical Reports Server (NTRS)

    Wilson, John W.; Cucinotta, Francis A.

    1991-01-01

    A repair/misrepair cell kinetics model is superimposed onto the track structure model of Katz to provide for a repair mechanism. The model is tested on the repair-dependent data of Yang et al. and provides an adequate description of that data. The misrepair rate determines the maximum relative biological effectiveness (RBE), but similar results could arise from indirect X-ray lethality not include in the present model.

  14. Mutagenic DNA repair in enterobacteria.

    PubMed Central

    Sedgwick, S G; Ho, C; Woodgate, R

    1991-01-01

    Sixteen species of enterobacteria have been screened for mutagenic DNA repair activity. In Escherichia coli, mutagenic DNA repair is encoded by the umuDC operon. Synthesis of UmuD and UmuC proteins is induced as part of the SOS response to DNA damage, and after induction, the UmuD protein undergoes an autocatalytic cleavage to produce the carboxy-terminal UmuD' fragment needed for induced mutagenesis. The presence of a similar system in other species was examined by using a combined approach of inducible-mutagenesis assays, cross-reactivity to E. coli UmuD and UmuD' antibodies to test for induction and cleavage of UmuD-like proteins, and hybridization with E. coli and Salmonella typhimurium umu DNA probes to map umu-like genes. The results indicate a more widespread distribution of mutagenic DNA repair in other species than was previously thought. They also show that umu loci can be more complex in other species than in E. coli. Differences in UV-induced mutability of more than 200-fold were seen between different species of enteric bacteria and even between multiple natural isolates of E. coli, and yet some of the species which display a poorly mutable phenotype still have umu-like genes and proteins. It is suggested that umDC genes can be curtailed in their mutagenic activities but that they may still participate in some other, unknown process which provides the continued stimulus for their retention. Images PMID:1885540

  15. Current Trends in Laparoscopic Ventral Hernia Repair

    PubMed Central

    Patapis, Paul; Zavras, Nick; Tzanetis, Panagiotis; Machairas, Anastasios

    2015-01-01

    Background and Objectives: The purpose of this study was to analyze the surgical technique, postoperative complications, and possible recurrence after laparoscopic ventral hernia repair (LVHR) in comparison with open ventral hernia repair (OVHR), based on the international literature. Database: A Medline search of the current English literature was performed using the terms laparoscopic ventral hernia repair and incisional hernia repair. Conclusions: LVHR is a safe alternative to the open method, with the main advantages being minimal postoperative pain, shorter recovery, and decreased wound and mesh infections. Incidental enterotomy can be avoided by using a meticulous technique and sharp dissection to avoid thermal injury. PMID:26273186

  16. Repair and rehabilitation with polymer concrete

    SciTech Connect

    Kukacka, L.E.

    1988-09-01

    As a result of their fast setting characteristics and excellent mechanical and physical properties, polymer concretes (PC) are finding ever increasing useage for the repair of deteriorated portland cement concrete structures. Applications include the repair of highway pavements and bridge decks, airport runways, hydrotechnical structures, tunnels, and industrial flooring. The most commonly used resins and monomer systems for these applications are epoxies, polyesters and methylmethacrylate. Furfuryl alcohol has been used experimentally, and shows promise for use in making emergency repairs under adverse moisture or extreme temperature conditions. In the paper, repair procedures will be discussed and several case histories given. 6 refs.

  17. 33 CFR 127.405 - Repairs.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas Maintenance § 127.405 Repairs. The operator shall ensure that—...

  18. 33 CFR 127.405 - Repairs.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas Maintenance § 127.405 Repairs. The operator shall ensure that—...

  19. 33 CFR 127.405 - Repairs.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas Maintenance § 127.405 Repairs. The operator shall ensure that—...

  20. 33 CFR 127.405 - Repairs.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... FACILITIES WATERFRONT FACILITIES HANDLING LIQUEFIED NATURAL GAS AND LIQUEFIED HAZARDOUS GAS Waterfront Facilities Handling Liquefied Natural Gas Maintenance § 127.405 Repairs. The operator shall ensure that—...

  1. Scaffold devices for rotator cuff repair.

    PubMed

    Ricchetti, Eric T; Aurora, Amit; Iannotti, Joseph P; Derwin, Kathleen A

    2012-02-01

    Rotator cuff tears affect 40% or more of those aged older than 60 years, and repair failure rates of 20% to 70% remain a significant clinical challenge. Hence, there is a need for repair strategies that can augment the repair by mechanically reinforcing it, while at the same time biologically enhancing the intrinsic healing potential of the tendon. Tissue engineering strategies to improve rotator cuff repair healing include the use of scaffolds, growth factors, and cell seeding, or a combination of these approaches. Currently, scaffolds derived from mammalian extracellular matrix, synthetic polymers, and a combination thereof, have been cleared by the U.S. Food and Drug Administration and are marketed as medical devices for rotator cuff repair in humans. Despite the growing clinical use of scaffold devices for rotator cuff repair, there are numerous questions related to their indication, surgical application, safety, mechanism of action, and efficacy that remain to be clarified or addressed. This article reviews the current basic science and clinical understanding of commercially available synthetic and extracellular matrix scaffolds for rotator cuff repair. Our review will emphasize the host response and scaffold remodeling, mechanical and suture-retention properties, and preclinical and clinical studies on the use of these scaffolds for rotator cuff repair. We will discuss the implications of these data on the future directions for use of these scaffolds in tendon repair procedures.

  2. Photomask repair using low-energetic electrons

    NASA Astrophysics Data System (ADS)

    Edinger, K.; Wolff, K.; Spies, P.; Luchs, T.; Schneider, H.; Auth, N.; Hermanns, Ch. F.; Waiblinger, M.

    2015-10-01

    Mask repair is an essential step in the mask manufacturing process as the extension of 193nm technology and the insertion of EUV are drivers for mask complexity and cost. The ability to repair all types of defects on all mask blank materials is crucial for the economic success of a mask shop operation. In the future mask repair is facing several challenges. The mask minimum features sizes are shrinking and require a higher resolution repair tool. At the same time mask blanks with different new mask materials are introduced to optimize optical performance and long term durability. For EUV masks new classes of defects like multilayer and phase defects are entering the stage. In order to achieve a high yield, mask repair has to cover etch and deposition capabilities and must not damage the mask. We will demonstrate in this paper that low energetic electron-beam (e-beam)-based mask repair is a commercially viable solution. Therefore we developed a new repair platform called MeRiT® neXT to address the technical challenges of this new technology. We will analyze the limits of the existing as well as lower energetic electron induced repair technologies theoretically and experimentally and show performance data on photomask reticles. Based on this data, we will give an outlook to future mask repair technology.

  3. Bladder and urethral repair - series (image)

    MedlinePlus

    ... urethral repair is usually performed to prevent urine leakage associated with stress incontinence. Stress incontinence is the involuntary leakage of urine when laughing, coughing, sneezing, or lifting, ...

  4. Scheduling and rescheduling with iterative repair

    NASA Technical Reports Server (NTRS)

    Zweben, Monte; Davis, Eugene; Daun, Brian; Deale, Michael

    1992-01-01

    This paper describes the GERRY scheduling and rescheduling system being applied to coordinate Space Shuttle Ground Processing. The system uses constraint-based iterative repair, a technique that starts with a complete but possibly flawed schedule and iteratively improves it by using constraint knowledge within repair heuristics. In this paper we explore the tradeoff between the informedness and the computational cost of several repair heuristics. We show empirically that some knowledge can greatly improve the convergence speed of a repair-based system, but that too much knowledge, such as the knowledge embodied within the MIN-CONFLICTS lookahead heuristic, can overwhelm a system and result in degraded performance.

  5. Integrated Electrical Wire Insulation Repair System

    NASA Technical Reports Server (NTRS)

    Williams, Martha; Jolley, Scott; Gibson, Tracy; Parks, Steven

    2013-01-01

    An integrated system tool will allow a technician to easily and quickly repair damaged high-performance electrical wire insulation in the field. Low-melt polyimides have been developed that can be processed into thin films that work well in the repair of damaged polyimide or fluoropolymer insulated electrical wiring. Such thin films can be used in wire insulation repairs by affixing a film of this low-melt polyimide to the damaged wire, and heating the film to effect melting, flow, and cure of the film. The resulting repair is robust, lightweight, and small in volume. The heating of this repair film is accomplished with the use of a common electrical soldering tool that has been modified with a special head or tip that can accommodate the size of wire being repaired. This repair method can furthermore be simplified for the repair technician by providing replaceable or disposable soldering tool heads that have repair film already "loaded" and ready for use. The soldering tool heating device can also be equipped with a battery power supply that will allow its use in areas where plug-in current is not available

  6. National results after ventral hernia repair.

    PubMed

    Helgstrand, Frederik

    2016-07-01

    Ventral hernia repairs are among the most frequently performed surgical procedures. The variations of repair techniques are multiple and outcome has been unacceptable. Despite the high volume, it has been difficult to obtain sufficient data to provide evidence for best practice. In order to monitor national surgical quality and provide the warranted high volume data, the first national ventral hernia register (The Danish Ventral Hernia Database) was established in 2007 in Denmark. The present study series show that data from a well-established database supported by clinical examinations, patient files, questionnaires, and administrative data makes it possible to obtain nationwide high volume data and to achieve evidence for better outcome in a complex surgical condition as ventral hernia. Due to the high volume and included variables on surgical technique, it is now possible to make analyses adjusting for a variety of surgical techniques and different hernia specifications. We documented high 30-day complications and recurrence rates for both primary and secondary ventral hernias in a nationwide cohort. Furthermore, recurrence found by clinical examination was shown to exceed the number of patients undergoing reoperation for recurrence by a factor 4-5. The nationwide adjusted analyses proved that open mesh and laparoscopic repair for umbilical and epigastric hernias does not differ in 30-day outcome or in risk of recurrence. There is a minor risk reduction in early complications after open sutured repairs. However, the risk for a later recurrence repair is significantly higher after sutured repairs compared with mesh repairs. The study series showed that large hernia defects and open re-pairs were independent predictors for 30-day complications after an incisional hernia repair. Open procedures and large hernia defects were independent risk factors for a later recurrence re-pair. However, patients with large defects (> 15 cm) seemed to benefit from an open mesh

  7. Mechanistic Modelling and Bayesian Inference Elucidates the Variable Dynamics of Double-Strand Break Repair

    PubMed Central

    2016-01-01

    DNA double-strand breaks are lesions that form during metabolism, DNA replication and exposure to mutagens. When a double-strand break occurs one of a number of repair mechanisms is recruited, all of which have differing propensities for mutational events. Despite DNA repair being of crucial importance, the relative contribution of these mechanisms and their regulatory interactions remain to be fully elucidated. Understanding these mutational processes will have a profound impact on our knowledge of genomic instability, with implications across health, disease and evolution. Here we present a new method to model the combined activation of non-homologous end joining, single strand annealing and alternative end joining, following exposure to ionising radiation. We use Bayesian statistics to integrate eight biological data sets of double-strand break repair curves under varying genetic knockouts and confirm that our model is predictive by re-simulating and comparing to additional data. Analysis of the model suggests that there are at least three disjoint modes of repair, which we assign as fast, slow and intermediate. Our results show that when multiple data sets are combined, the rate for intermediate repair is variable amongst genetic knockouts. Further analysis suggests that the ratio between slow and intermediate repair depends on the presence or absence of DNA-PKcs and Ku70, which implies that non-homologous end joining and alternative end joining are not independent. Finally, we consider the proportion of double-strand breaks within each mechanism as a time series and predict activity as a function of repair rate. We outline how our insights can be directly tested using imaging and sequencing techniques and conclude that there is evidence of variable dynamics in alternative repair pathways. Our approach is an important step towards providing a unifying theoretical framework for the dynamics of DNA repair processes. PMID:27741226

  8. Mycobacteria exploit three genetically distinct DNA double-strand break repair pathways

    PubMed Central

    Gupta, Richa; Barkan, Daniel; Redelman-Sidi, Gil; Shuman, Stewart; Glickman, Michael S.

    2013-01-01

    Bacterial pathogens rely on their DNA repair pathways to resist genomic damage inflicted by the host. DNA double-strand breaks (DSBs) are especially threatening to bacterial viability. DSB repair by homologous recombination (HR) requires nucleases that resect DSB ends and a strand exchange protein that facilitates homology search. RecBCD and RecA perform these functions in E. coli and constitute the major pathway of error free DSB repair. Mycobacteria, including the human pathogen M. tuberculosis, elaborate an additional error-prone pathway of DSB repair via nonhomologous end-joining (NHEJ) catalyzed by Ku and DNA ligase D (LigD). Little is known about the relative contributions of HR and NHEJ to mycobacterial chromosome repair, the factors that dictate pathway choice, or the existence of additional DSB repair pathways. Here we demonstrate that Mycobacterium smegmatis has three DSB repair pathway options: HR, NHEJ, and a novel mechanism of single-strand annealing (SSA). Inactivation of NHEJ or SSA is compensated by elevated HR. We find that mycobacterial RecBCD does not participate in HR or confer resistance to ionizing radiation (IR), but is required for the RecA-independent SSA pathway. In contrast, the mycobacterial helicase-nuclease AdnAB participates in the RecA-dependent HR pathway, and is a major determinant of resistance to IR and oxidative DNA damage. These findings reveal distinctive features of mycobacterial DSB repair, most notably the dedication of the RecBCD and AdnAB helicase-nuclease machines to distinct repair pathways. PMID:21219454

  9. 14 CFR 145.107 - Satellite repair stations.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Satellite repair stations. 145.107 Section... Data § 145.107 Satellite repair stations. (a) A certificated repair station under the managerial control of another certificated repair station may operate as a satellite repair station with its...

  10. 14 CFR 145.107 - Satellite repair stations.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Satellite repair stations. 145.107 Section... Data § 145.107 Satellite repair stations. (a) A certificated repair station under the managerial control of another certificated repair station may operate as a satellite repair station with its...

  11. 14 CFR 145.107 - Satellite repair stations.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Satellite repair stations. 145.107 Section... Data § 145.107 Satellite repair stations. (a) A certificated repair station under the managerial control of another certificated repair station may operate as a satellite repair station with its...

  12. 14 CFR 145.107 - Satellite repair stations.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Satellite repair stations. 145.107 Section... Data § 145.107 Satellite repair stations. (a) A certificated repair station under the managerial control of another certificated repair station may operate as a satellite repair station with its...

  13. 14 CFR 145.107 - Satellite repair stations.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Satellite repair stations. 145.107 Section... Data § 145.107 Satellite repair stations. (a) A certificated repair station under the managerial control of another certificated repair station may operate as a satellite repair station with its...

  14. 14 CFR 145.207 - Repair station manual.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Repair station manual. 145.207 Section 145...) SCHOOLS AND OTHER CERTIFICATED AGENCIES REPAIR STATIONS Operating Rules § 145.207 Repair station manual. (a) A certificated repair station must prepare and follow a repair station manual acceptable to...

  15. 40 CFR 60.482-9 - Standards: Delay of repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Delay of repair. 60.482-9... Standards: Delay of repair. (a) Delay of repair of equipment for which leaks have been detected will be allowed if repair within 15 days is technically infeasible without a process unit shutdown. Repair of...

  16. 21 CFR 870.1350 - Catheter balloon repair kit.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Catheter balloon repair kit. 870.1350 Section 870... repair kit. (a) Identification. A catheter balloon repair kit is a device used to repair or replace the... effect the repair or replacement. (b) Classification. Class III (premarket approval). (c) Date PMA...

  17. 14 CFR 145.207 - Repair station manual.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Repair station manual. 145.207 Section 145...) SCHOOLS AND OTHER CERTIFICATED AGENCIES REPAIR STATIONS Operating Rules § 145.207 Repair station manual. (a) A certificated repair station must prepare and follow a repair station manual acceptable to...

  18. 24 CFR 206.47 - Property standards; repair work.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 24 Housing and Urban Development 2 2010-04-01 2010-04-01 false Property standards; repair work... Property standards; repair work. (a) Need for repairs. Properties must meet the applicable property... insured mortgage. (b) Assurance that repairs are made. The mortgage may be closed before the repair...

  19. 24 CFR 206.47 - Property standards; repair work.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 24 Housing and Urban Development 2 2014-04-01 2014-04-01 false Property standards; repair work... Property standards; repair work. (a) Need for repairs. Properties must meet the applicable property... insured mortgage. (b) Assurance that repairs are made. The mortgage may be closed before the repair...

  20. A history of the DNA repair and mutagenesis field: The discovery of base excision repair.

    PubMed

    Friedberg, Errol C

    2016-01-01

    This article reviews the early history of the discovery of an DNA repair pathway designated as base excision repair (BER), since in contrast to the enzyme-catalyzed removal of damaged bases from DNA as nucleotides [called nucleotide excision repair (NER)], BER involves the removal of damaged or inappropriate bases, such as the presence of uracil instead of thymine, from DNA as free bases.

  1. Initiating Repair and Beyond: The Use of Two Repeat-Formatted Repair Initiations in Mandarin Conversation

    ERIC Educational Resources Information Center

    Wu, Ruey-Jiuan Regina

    2006-01-01

    As part of a growing effort to understand the organization of repair across languages, this study examines 2 repeat-formatted other-initiated repair practices in Mandarin conversation. Using the methodology of conversation analysis as a central framework, this study shows that the 2 Mandarin repair initiations under examination, like…

  2. 49 CFR 1242.42 - Administration, repair and maintenance, machinery repair, equipment damaged, dismantling retired...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... repair, equipment damaged, dismantling retired property, fringe benefits, other casualties and insurance, lease rentals, joint facility rents, other rents, depreciation, joint facility, repairs billed to others... PASSENGER SERVICE FOR RAILROADS 1 Operating Expenses-Equipment § 1242.42 Administration, repair...

  3. DNA repair decline during mouse spermiogenesis results in the accumulation of heritable DNA damage

    SciTech Connect

    Marchetti, Francesco; Marchetti, Francesco; Wryobek, Andrew J

    2008-02-21

    The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7- 1 dbf). Analysis of chromosomalaberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a linear response for both single and repeated exposures. These findings show that the differential DNA repair capacity of post-meioitic male germ cells has a major impact on the risk of paternally transmitted heritable damage and suggest that chronic exposures that may occur in the weeks prior to fertilization because of occupational or lifestyle factors (i.e, smoking) can lead to an accumulation of genetic damage in sperm and result in heritable chromosomal aberrations of paternal origin.

  4. DNA Repair Decline During Mouse Spermiogenesis Results in the Accumulation of Heritable DNA Damage

    SciTech Connect

    Marchetti, Francesco; Marchetti, Francesco; Wyrobek, Andrew J.

    2007-12-01

    The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7-1 dbf). Analysis of chromosomal aberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a linear response for both single and repeated exposures. These findings show that the differential DNA repair capacity of post-meioitic male germ cells has a major impact on the risk of paternally transmitted heritable damage and suggest that chronic exposures that may occur in the weeks prior to fertilization because of occupational or lifestyle factors (i.e, smoking) can lead to an accumulation of genetic damage in sperm and result in heritable chromosomal aberrations of paternal origin.

  5. Targeting Microtubules for Wound Repair

    PubMed Central

    Charafeddine, Rabab A.; Nosanchuk, Joshua D.; Sharp, David J.

    2016-01-01

    Significance: Fast and seamless healing is essential for both deep and chronic wounds to restore the skin and protect the body from harmful pathogens. Thus, finding new targets that can both expedite and enhance the repair process without altering the upstream signaling milieu and causing serious side effects can improve the way we treat wounds. Since cell migration is key during the different stages of wound healing, it presents an ideal process and intracellular structural machineries to target. Recent Advances and Critical Issues: The microtubule (MT) cytoskeleton is rising as an important structural and functional regulator of wound healing. MTs have been reported to play different roles in the migration of the various cell types involved in wound healing. Specific microtubule regulatory proteins (MRPs) can be targeted to alter a section or subtype of the MT cytoskeleton and boost or hinder cell motility. However, inhibiting intracellular components can be challenging in vivo, especially using unstable molecules, such as small interfering RNA. Nanoparticles can be used to protect these unstable molecules and topically deliver them to the wound. Utilizing this approach, we recently showed that fidgetin-like 2, an uncharacterized MRP, can be targeted to enhance cell migration and wound healing. Future Directions: To harness the full potential of the current MRP therapeutic targets, studies should test them with different delivery platforms, dosages, and skin models. Screening for new MT effectors that boost cell migration in vivo would also help find new targets for skin repair. PMID:27785378

  6. Repair of overheating linear accelerator

    SciTech Connect

    Barkley, Walter; Baldwin, William; Bennett, Gloria; Bitteker, Leo; Borden, Michael; Casados, Jeff; Fitzgerald, Daniel; Gorman, Fred; Johnson, Kenneth; Kurennoy, Sergey; Martinez, Alberto; O’Hara, James; Perez, Edward; Roller, Brandon; Rybarcyk, Lawrence; Stark, Peter; Stockton, Jerry

    2004-01-01

    Los Alamos Neutron Science Center (LANSCE) is a proton accelerator that produces high energy particle beams for experiments. These beams include neutrons and protons for diverse uses including radiography, isotope production, small feature study, lattice vibrations and material science. The Drift Tube Linear Accelerator (DTL) is the first portion of a half mile long linear section of accelerator that raises the beam energy from 750 keV to 100 MeV. In its 31st year of operation (2003), the DTL experienced serious issues. The first problem was the inability to maintain resonant frequency at full power. The second problem was increased occurrences of over-temperature failure of cooling hoses. These shortcomings led to an investigation during the 2003 yearly preventative maintenance shutdown that showed evidence of excessive heating: discolored interior tank walls and coper oxide deposition in the cooling circuits. Since overheating was suspected to be caused by compromised heat transfer, improving that was the focus of the repair effort. Investigations revealed copper oxide flow inhibition and iron oxide scale build up. Acid cleaning was implemented with careful attention to protection of the base metal, selection of components to clean and minimization of exposure times. The effort has been very successful in bringing the accelerator through a complete eight month run cycle allowing an incredible array of scientific experiments to be completed this year (2003-2004). This paper will describe the systems, investigation analysis, repair, return to production and conclusion.

  7. Effect of repair surface design, repair material, and processing method on the transverse strength of repaired acrylic denture resin.

    PubMed

    Ward, J E; Moon, P C; Levine, R A; Behrendt, C L

    1992-06-01

    The transverse strengths of blocks of denture base acrylic resin repaired with autopolymerizing monomer and polymer and autopolymerizing monomer and heat-cured polymer were measured with a three-point bending test. Three repair joints were studied: butt, round, and 45-degree bevel. Three processing methods were used: bench cure, hydroflask with hot water for 10 minutes, and hydroflask with hot water for 30 minutes. The strengths of repairs made with round and 45-degree bevel joint designs were similar and significantly greater than those with a butt joint design. The strengths of repairs processed in a hydroflask for 10 minutes and 30 minutes were similar and significantly greater than those cured on the bench top. There was no difference in the strength of repairs made with autopolymerizing monomer and polymer and autopolymerizing monomer and heat-cured polymer.

  8. International congress on DNA damage and repair: Book of abstracts

    SciTech Connect

    Not Available

    1987-01-01

    This document contains the abstracts of 105 papers presented at the Congress. Topics covered include the Escherichia coli nucleotide excision repair system, DNA repair in malignant transformations, defective DNA repair, and gene regulation. (TEM)

  9. AUTOMOTIVE REPAIR SHOP, DETAIL OF BUILDING CORNER (MAIN WING) SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, DETAIL OF BUILDING CORNER (MAIN WING) SHOWING WOOD EAVE AND STUCCO RAKEBOARD ON GABLE END, WITH SCALE. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  10. AUTOMOTIVE REPAIR SHOP, INTERIOR VIEW TO SOUTHEAST, DOORWAYS TO SHOP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, INTERIOR VIEW TO SOUTHEAST, DOORWAYS TO SHOP OFFICE AND SOUTH WING, WITH SCALE. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  11. AUTOMOTIVE REPAIR SHOP, DETAIL OF FABRICATING PRESS IN EAST END ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, DETAIL OF FABRICATING PRESS IN EAST END OF MAIN WING, WITH SCALE. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  12. AUTOMOTIVE REPAIR SHOP, INTERIOR VIEW TO SOUTHEAST, DOORWAYS TO SHOP ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, INTERIOR VIEW TO SOUTHEAST, DOORWAYS TO SHOP OFFICE AND SOUTH WING. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  13. AUTOMOTIVE REPAIR SHOP, DETAIL OF MILLS COAL BOILER WITH SCREWFEED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, DETAIL OF MILLS COAL BOILER WITH SCREW-FEED COAL HOPPER ON RIGHT SIDE. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  14. AUTOMOTIVE REPAIR SHOP, SLIDING DOOR LEADING TO BOILER ROOM ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, SLIDING DOOR LEADING TO BOILER ROOM ON SOUTH SIDE OF SOUTH WING, WITH SCALE. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  15. Lube rack of Automotive and Tractor Repair Shops with Warehousefield ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Lube rack of Automotive and Tractor Repair Shops with Warehouse-field Equipment Repair Shop Building's wall to the right, looking from the south - Kekaha Sugar Company, Automotive and Tractor Repair Shops, 8315 Kekaha Road, Kekaha, Kauai County, HI

  16. AUTOMOTIVE REPAIR SHOP, SLIDING DOOR LEADING TO BOILER ROOM ON ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, SLIDING DOOR LEADING TO BOILER ROOM ON SOUTH SIDE OF SOUTH WING. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  17. AUTOMOTIVE REPAIR SHOP, DETAIL OF BUILDING CORNER (MAIN WING) SHOWING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, DETAIL OF BUILDING CORNER (MAIN WING) SHOWING WOOD EAVE AND STUCCO RAKEBOARD ON GABLE END. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  18. AUTOMOTIVE REPAIR SHOP, DETAIL OF MILLS COAL BOILER WITH SCREWFEED ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    AUTOMOTIVE REPAIR SHOP, DETAIL OF MILLS COAL BOILER WITH SCREW-FEED COAL HOPPER ON RIGHT SIDE, WITH SCALE. - Cedar City Automotive Repair Shop, Automotive Repair Shop, 820 North Main Street, Cedar City, Iron County, UT

  19. Mismatch repair of heteroduplex DNA intermediates of extrachromosomal recombination in mammalian cells.

    PubMed Central

    Deng, W P; Nickoloff, J A

    1994-01-01

    Previous work indicated that extrachromosomal recombination in mammalian cells could be explained by the single-strand annealing (SSA) model. This model predicts that extrachromosomal recombination leads to nonconservative crossover products and that heteroduplex DNA (hDNA) is formed by annealing of complementary single strands. Mismatched bases in hDNA may subsequently be repaired to wild-type or mutant sequences, or they may remain unrepaired and segregate following DNA replication. We describe a system to examine the formation and mismatch repair of hDNA in recombination intermediates. Our results are consistent with extrachromosomal recombination occurring via SSA and producing crossover recombinant products. As predicted by the SSA model, hDNA was present in double-strand break-induced recombination intermediates. By placing either silent or frameshift mutations in the predicted hDNA region, we have shown that mismatches are efficiently repaired prior to DNA replication. Images PMID:8264607

  20. Railroad track repairs are complete at KSC

    NASA Technical Reports Server (NTRS)

    2000-01-01

    Railroad track repairs have been completed at Kennedy Space Center. This section of track is located on KSC property, just north of the NASA Causeway in the KSC Industrial Area. The repairs were required following the minor derailment of two solid rocket booster segment cars on July 18.

  1. Repair of major system elements on Skylab

    NASA Technical Reports Server (NTRS)

    Pace, R. E., Jr.

    1974-01-01

    In-flight maintenance, as conceived and preplanned for the Skylab mission was limited to simple scheduled and unscheduled replacement tasks and minor contingency repairs. Tools and spares were provided accordingly. However, failures during the mission dictated complicated and sophisticated repairs to major systems so that the mission could continue. These repairs included the release of a large structure that failed to deploy, the assembly and deployment of large mechanical devices, the installation and checkout of precision electronic equipment, troubleshooting and repair of precision electromechanical equipment, and tapping into and recharging a cooling system. The repairs were conducted both inside the spacecraft and during extravehicular activities. Some of the repair tasks required team effort on the part of the crewmen including close procedural coordination between internal and extravehicular crewmen. The Skylab experience indicates that crewmen can, with adequate training, make major system repairs in space using standard or special tools. Design of future spacecraft systems should acknowledge this capability and provide for more extensive in-flight repair and maintenance.

  2. Mitral valve repair in acquired dextrocardia.

    PubMed

    Elmistekawy, Elsayed; Chan, Vincent; Hynes, Mark; Mesana, Thierry

    2015-10-01

    Surgical correction of valvular heart disease in patients with dextrocardia is extremely rare. We report a surgical case of mitral valve repair in a patient with acquired dextrocardia. Successful mitral valve repair was performed through a right lateral thoracotomy. We describe our surgical strategy and summarize the literature.

  3. Appliance Repair. Post Secondary Curriculum Guide.

    ERIC Educational Resources Information Center

    Watkins, James F.; And Others

    This curriculum guide was designed for use in postsecondary appliance repair education programs in Georgia. Its purpose is to provide for development of entry level skills in appliance repair in the areas of knowledge, theoretical structure, tool usage, diagnostic ability, related supportive skills, and occupational survival skills. The first…

  4. 40 CFR 63.1024 - Leak repair.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... reading measured by Method 21 of 40 CFR part 60, appendix A at the time the leak is successfully repaired... detected. First attempt at repair for pumps includes, but is not limited to, tightening the packing gland... the bonnet bolts, and/or tightening the packing gland nuts, and/or injecting lubricant into...

  5. 40 CFR 63.1024 - Leak repair.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... reading measured by Method 21 of 40 CFR part 60, appendix A at the time the leak is successfully repaired... detected. First attempt at repair for pumps includes, but is not limited to, tightening the packing gland... the bonnet bolts, and/or tightening the packing gland nuts, and/or injecting lubricant into...

  6. 40 CFR 63.1024 - Leak repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... reading measured by Method 21 of 40 CFR part 60, appendix A at the time the leak is successfully repaired... detected. First attempt at repair for pumps includes, but is not limited to, tightening the packing gland... the bonnet bolts, and/or tightening the packing gland nuts, and/or injecting lubricant into...

  7. Thermal protection system flight repair kit

    NASA Technical Reports Server (NTRS)

    1979-01-01

    A thermal protection system (TPS) flight repair kit required for use on a flight of the Space Transportation System is defined. A means of making TPS repairs in orbit by the crew via extravehicular activity is discussed. A cure in place ablator, a precured ablator (large area application), and packaging design (containers for mixing and dispensing) for the TPS are investigated.

  8. 30 CFR 57.6801 - Vehicle repair.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Vehicle repair. 57.6801 Section 57.6801 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... and Underground § 57.6801 Vehicle repair. Vehicles containing explosive material and oxidizers...

  9. 30 CFR 56.6801 - Vehicle repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Vehicle repair. 56.6801 Section 56.6801 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Vehicle repair. Vehicles containing explosive material and oxidizers shall not be taken into a...

  10. 30 CFR 56.6801 - Vehicle repair.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Vehicle repair. 56.6801 Section 56.6801 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... Vehicle repair. Vehicles containing explosive material and oxidizers shall not be taken into a...

  11. 30 CFR 57.6801 - Vehicle repair.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 30 Mineral Resources 1 2010-07-01 2010-07-01 false Vehicle repair. 57.6801 Section 57.6801 Mineral Resources MINE SAFETY AND HEALTH ADMINISTRATION, DEPARTMENT OF LABOR METAL AND NONMETAL MINE SAFETY AND... and Underground § 57.6801 Vehicle repair. Vehicles containing explosive material and oxidizers...

  12. Novel EUV Mask Blank Defect Repair Developments

    SciTech Connect

    Hau-Riege, S; Barty, A; Mirkarimi, P

    2003-03-31

    The development of defect-free reticle blanks is an important challenge facing the commercialization of extreme ultraviolet lithography (EUVL). The basis of EUVL reticles are mask blanks consisting of a substrate and a reflective Mo/Si multilayer. Defects on the substrate or defects introduced during multilayer deposition can result in critical phase and amplitude defects. Amplitude- or phase-defect repair techniques are being developed with the goal to repair many of these defects. In this report, we discuss progress in two areas of defect repair: (1) We discuss the effect of the residual reflectance variation over the repair zone after amplitude-defect repair on the process window. This allows the determination of the maximum tolerable residual damage induced by amplitude defect repair. (2) We further performed a quantitative assessment of the yield improvement due to defect repair. We found that amplitude- and phase-defect repair have the potential to significantly improve mask blank yield. Our calculations further show that yield can be maximized by increasing the number of Mo/Si bilayers.

  13. 33 CFR 127.1405 - Repairs.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Repairs. 127.1405 Section 127.1405 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... Waterfront Facilities Handling Liquefied Hazardous Gas Maintenance § 127.1405 Repairs. Each operator of...

  14. Self repairing composites for drone air vehicles

    NASA Astrophysics Data System (ADS)

    Dry, Carolyn

    2015-04-01

    The objective of this effort was to demonstrate the feasibility of impact-initiated delivery of repair chemicals through hollow fiber architectures embedded within graphite fiber reinforced polymer matrix composites, representative of advanced drone aircraft component material systems. Self-repairing structures through coupon and elements were demonstrated, and evaluated.

  15. 40 CFR 280.33 - Repairs allowed.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... STANDARDS AND CORRECTIVE ACTION REQUIREMENTS FOR OWNERS AND OPERATORS OF UNDERGROUND STORAGE TANKS (UST) General Operating Requirements § 280.33 Repairs allowed. Owners and operators of UST systems must ensure... operating properly. (f) UST system owners and operators must maintain records of each repair for...

  16. 40 CFR 280.33 - Repairs allowed.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... STANDARDS AND CORRECTIVE ACTION REQUIREMENTS FOR OWNERS AND OPERATORS OF UNDERGROUND STORAGE TANKS (UST) General Operating Requirements § 280.33 Repairs allowed. Owners and operators of UST systems must ensure... operating properly. (f) UST system owners and operators must maintain records of each repair for...

  17. Self-repairing composites for airplane components

    NASA Astrophysics Data System (ADS)

    Dry, Carolyn

    2008-03-01

    Durability and damage tolerance criteria drives the design of most composite structures. Those criteria could be altered by developing structure that repairs itself from impact damage. This is a technology for increasing damage tolerance for impact damage. Repaired damage would enable continued function and prevent further degradation to catastrophic failure in the case of an aircraft application. Further, repaired damage would enable applications to be utilized without reduction in performance due to impacts. Self repairing structures are designed to incorporate hollow fibers, which will release a repairing agent when the structure is impacted, so that the repairing agent will fill delaminations, voids and cracks in les than one minute, thus healing matrix voids. The intent is to modify the durability and damage tolerance criteria by incorporation of self-healing technologies to reduce overall weight: The structure will actually remain lighter than current conventional design procedures allow. Research objective(s) were: Prove that damage can be repaired to within 80-90% of original flexural strength in less than one minute, in laminates that are processed at 300-350F typical for aircraft composites. These were successfully met. The main focus was on testing of elements in compression after impact and a larger component in shear at Natural Process Design, Inc. Based on these results the advantages purposes are assessed. The results show potential; with self repairing composites, compressive strength is maintained sufficiently so that less material can be used as per durability and damage tolerance, yielding a lighter structure.

  18. Human DNA repair and recombination genes

    SciTech Connect

    Thompson, L.H.; Weber, C.A.; Jones, N.J.

    1988-09-01

    Several genes involved in mammalian DNA repair pathways were identified by complementation analysis and chromosomal mapping based on hybrid cells. Eight complementation groups of rodent mutants defective in the repair of uv radiation damage are now identified. At least seven of these genes are probably essential for repair and at least six of them control the incision step. The many genes required for repair of DNA cross-linking damage show overlap with those involved in the repair of uv damage, but some of these genes appear to be unique for cross-link repair. Two genes residing on human chromosome 19 were cloned from genomic transformants using a cosmid vector, and near full-length cDNA clones of each gene were isolated and sequenced. Gene ERCC2 efficiently corrects the defect in CHO UV5, a nucleotide excision repair mutant. Gene XRCC1 normalizes repair of strand breaks and the excessive sister chromatid exchange in CHO mutant EM9. ERCC2 shows a remarkable /approximately/52% overall homology at both the amino acid and nucleotide levels with the yeast RAD3 gene. Evidence based on mutation induction frequencies suggests that ERCC2, like RAD3, might also be an essential gene for viability. 100 refs., 4 tabs.

  19. Repairers must relabel instruments, court rules.

    PubMed

    2002-08-01

    A federal appeals court decided that repair companies must be sure that endoscopic instruments they have worked on, especially those they have drastically altered, must be clearly identified as such. In some cases, that could mean that the original manufacturer's name must be removed, or the repairer's name added to the device's label. PMID:12232895

  20. Pectus excavatum repair from a plastic surgeon’s perspective

    PubMed Central

    2016-01-01

    Minimally invasive repair of pectus excavatum (MIRPE) or similar procedures for pectus excavatum (PE) repair, nowadays no longer performed by one single speciality, may not always achieve sufficient aesthetic results, particularly in the infrapectoral or infraxiphoidal region. Reasons for this include the diaphragm inhibiting correct positioning of the bars, as well as asymmetric deformities which may still be present after remodelling attempts. Furthermore, some cases develop a mild recurrence or partial concavity once the correction bar is removed. However, any secondary re-do MIRPE procedure remains risky because of adhesions between the pleura, lung, pericardium, thoracic wall as residuals from the primary intervention. Treatment options as secondary correction for these deformities may include open access surgery, resection or reshaping of deformed costal cartilage. Moreover, augmentation of a residual concave area can be achieved by autologous transplantation of resected over-abundant cartilage, as well as by liposhifting or implantation of customized alloplastics. A physician dealing with PE corrections should be familiar with various shaping and complementary reconstructive techniques in order to provide the best options for a variety of expressions of anterior wall deformities. Among treating surgeons, there is an awareness that no single method can be applied for every kind of funnel chest deformity. An appropriate technique, either as a single approach for the ordinary deformities or in conjunction with ancillary procedures for the intricate cases, should be selected carefully based on the heterogeneity of symptoms, severity, expectations and surgical skill in addition to the available equipment. Out of a variety of such ancillary procedures available and based on experience within general plastic reconstructive surgery, some techniques for PE repair are explained and illustrated here with their advantages and disadvantages. PMID:27747184

  1. Analysis of Direct Costs of Outpatient Arthroscopic Rotator Cuff Repair.

    PubMed

    Narvy, Steven J; Ahluwalia, Avtar; Vangsness, C Thomas

    2016-01-01

    Arthroscopic rotator cuff surgery is one of the most commonly performed orthopedic surgical procedures. We conducted a study to calculate the direct cost of arthroscopic repair of rotator cuff tears confirmed by magnetic resonance imaging. Twenty-eight shoulders in 26 patients (mean age, 54.5 years) underwent primary rotator cuff repair by a single fellowship-trained arthroscopic surgeon in the outpatient surgery center of a major academic medical center. All patients had interscalene blocks placed while in the preoperative holding area. Direct costs of this cycle of care were calculated using the time-driven activity-based costing algorithm. Mean time in operating room was 148 minutes; mean time in recovery was 105 minutes. Calculated surgical cost for this process cycle was $5904.21. Among material costs, suture anchor costs were the main cost driver. Preoperative bloodwork was obtained in 23 cases, adding a mean cost of $111.04. Our findings provide important preliminary information regarding the direct economic costs of rotator cuff surgery and may be useful to hospitals and surgery centers negotiating procedural reimbursement for the increased cost of repairing complex tears. PMID:26761928

  2. Analysis of Direct Costs of Outpatient Arthroscopic Rotator Cuff Repair.

    PubMed

    Narvy, Steven J; Ahluwalia, Avtar; Vangsness, C Thomas

    2016-01-01

    Arthroscopic rotator cuff surgery is one of the most commonly performed orthopedic surgical procedures. We conducted a study to calculate the direct cost of arthroscopic repair of rotator cuff tears confirmed by magnetic resonance imaging. Twenty-eight shoulders in 26 patients (mean age, 54.5 years) underwent primary rotator cuff repair by a single fellowship-trained arthroscopic surgeon in the outpatient surgery center of a major academic medical center. All patients had interscalene blocks placed while in the preoperative holding area. Direct costs of this cycle of care were calculated using the time-driven activity-based costing algorithm. Mean time in operating room was 148 minutes; mean time in recovery was 105 minutes. Calculated surgical cost for this process cycle was $5904.21. Among material costs, suture anchor costs were the main cost driver. Preoperative bloodwork was obtained in 23 cases, adding a mean cost of $111.04. Our findings provide important preliminary information regarding the direct economic costs of rotator cuff surgery and may be useful to hospitals and surgery centers negotiating procedural reimbursement for the increased cost of repairing complex tears.

  3. Breaking bad: The mutagenic effect of DNA repair

    PubMed Central

    2015-01-01

    Species survival depends on the faithful replication of genetic information, which is continually monitored and maintained by DNA repair pathways thatcorrect replication errors and the thousands of lesions that arise daily from the inherent chemical lability of DNA and the effects of genotoxic agents. Nonetheless,neutrally evolving DNA (not under purifying selection) accumulates base substitutions with time (the neutral mutation rate). Thus, repair processes are not 100% efficient. The neutral mutation rate varies both between and within chromosomes. For example it is 10 – 50 fold higher at CpGsthan at non-CpG positions. Interestingly, the neutral mutation rate at non-CpG sites is positively correlated with CpG content. Althoughthe basis of this correlation was not immediately apparent,some bioinformatic results were consistent with the induction of non-CpGmutations byDNA repairat flanking CpG sites. Recent studies with a model system showed that in vivo repair of preformed lesions (mismatches, abasic sites, single stranded nicks) can in factinduce mutations in flanking DNA. Mismatch repair (MMR) is an essential component for repair-induced mutations, which can occur as distant as 5 kb from the introduced lesions. Most, but not all, mutations involved the C of TpCpN (G of NpGpA) which is the target sequence of the C-preferringsingle-stranded DNA specific APOBEC deaminases. APOBEC-mediated mutations are not limited to our model system: Recent studies by others showed that some tumors harbor mutations with the same signature, as can intermediates in RNA-guided endonuclease-mediated genome editing. APOBEC deaminases participate in normal physiological functions such as generating mutations that inactivate viruses or endogenous retrotransposons, or that enhance immunoglobulin diversity in B cells. The recruitment of normally physiological errorprone processes during DNA repairwould have important implications for disease, aging and evolution. This perspective briefly

  4. Quadriceps tendon rupture: a biomechanical comparison of transosseous equivalent double-row suture anchor versus transosseous tunnel repair.

    PubMed

    Hart, Nathan D; Wallace, Matthew K; Scovell, J Field; Krupp, Ryan J; Cook, Chad; Wyland, Douglas J

    2012-09-01

    Quadriceps rupture off the patella is traditionally repaired by a transosseous tunnel technique, although a single-row suture anchor repair has recently been described. This study biomechanically tested a new transosseous equivalent (TE) double-row suture anchor technique compared with the transosseous repair for quadriceps repair. After simulated quadriceps-patella avulsion in 10 matched cadaveric knees, repairs were completed by either a three tunnel transosseous (TT = 5) or a TE suture anchor (TE = 5) technique. Double-row repairs were done using two 5.5 Bio-Corkscrew FT (fully threaded) (Arthrex, Inc., Naples, FL, USA) and two 3.5 Bio-PushLock anchors (Arthrex, Inc., Naples, FL, USA) with all 10 repairs done with #2 FiberWire suture (Arthrex, Inc., Naples, FL). Cyclic testing from 50 to 250 N for 250 cycles and pull to failure load (1 mm/s) were undertaken. Gap formation and ultimate tensile load (N) were recorded and stiffness data (N/mm) were calculated. Statistical analysis was performed using a Mann-Whitney U test and survival characteristics examined with Kaplan-Meier test. No significant difference was found between the TE and TT groups in stiffness (TE = 134 +/- 15 N/mm, TT = 132 +/- 26 N/mm, p = 0.28). The TE group had significantly less ultimate tensile load (N) compared with the TT group (TE = 447 +/- 86 N, TT = 591 +/- 84 N, p = 0.04), with all failures occurring at the suture eyelets. Although both quadriceps repairs were sufficiently strong, the transosseous repairs were stronger than the TE suture anchor repairs. The repair stiffness and gap formation were similar between the groups.

  5. Stem cells in cardiac repair.

    PubMed

    Henning, Robert J

    2011-01-01

    in cardiac repair including identifying the optimal stem cell(s) that permit transplantation without requirements for host immune suppression; timing of stem cell transplantation that maximizes chemoattraction of stem cells to infarcts; and determining the optimal technique for injecting stem cells for cardiac repair. Techniques must be developed to enhance survival and propagation of stem cells in the myocardium. These studies will require close cooperation and interaction of scientists and clinicians. Cell-based cardiac repair in the 21st century will offer new hope for millions of patients worldwide with myocardial infarctions who, otherwise, would suffer from the relentless progression of heart disease to heart failure and death. PMID:21174514

  6. Repair Development for a Composite Cryotank

    NASA Technical Reports Server (NTRS)

    Cox, Sarah B.; Danley, Susan E.; Caraccio, Anne J.; Cheshire, Brian C.; Sampson, Jeffrey W.; Taylor, Brian J.

    2014-01-01

    The Composite Cryotank Technologies and Demonstration Project is working to advance the technologies for composite cryogenic propellant tanks at diameters suitable for future heavy lift vehicles and other in-space applications. The main goals of the project are to reduce weight and cost. One aspect of this project has focused on damage evaluation and repair development. Test panels have been impacted, repaired, and tested. Several repair methods were used to compare their effectiveness at restoring the integrity of the composite. Panels were evaluated by nondestructive evaluations at several points during the process to assess the damage and repair. The testing performed and the results and conclusions from the nondestructive evaluations and the destructive testing will be discussed. These results will lead to further development of inspection techniques and repair methods.

  7. DNA Triplet Repeat Expansion and Mismatch Repair

    PubMed Central

    Iyer, Ravi R.; Pluciennik, Anna; Napierala, Marek; Wells, Robert D.

    2016-01-01

    DNA mismatch repair is a conserved antimutagenic pathway that maintains genomic stability through rectification of DNA replication errors and attenuation of chromosomal rearrangements. Paradoxically, mutagenic action of mismatch repair has been implicated as a cause of triplet repeat expansions that cause neurological diseases such as Huntington disease and myotonic dystrophy. This mutagenic process requires the mismatch recognition factor MutSβ and the MutLα (and/or possibly MutLγ) endonuclease, and is thought to be triggered by the transient formation of unusual DNA structures within the expanded triplet repeat element. This review summarizes the current knowledge of DNA mismatch repair involvement in triplet repeat expansion, which encompasses in vitro biochemical findings, cellular studies, and various in vivo transgenic animal model experiments. We present current mechanistic hypotheses regarding mismatch repair protein function in mediating triplet repeat expansions and discuss potential therapeutic approaches targeting the mismatch repair pathway. PMID:25580529

  8. Repairing native defects on EUV mask blanks

    NASA Astrophysics Data System (ADS)

    Lawliss, Mark; Gallagher, Emily; Hibbs, Michael; Seki, Kazunori; Isogawa, Takeshi; Robinson, Tod; LeClaire, Jeff

    2014-10-01

    Mask defectivity is a serious problem for all lithographic masks, but especially for EUV masks. Defects in the EUV blank are particularly challenging because their elimination is beyond control of the mask fab. If defects have been identified on a mask blank, patterns can be shifted to place as many blank defects as possible in regions where printing impact will be eliminated or become unimportant. For those defects that cannot be mitigated through pattern shift, repair strategies must be developed. Repairing defects that occur naturally in the EUV blank is challenging because the printability of these defects varies widely. This paper describes some types of native defects commonly found and begins to outline a triage strategy for defects that are identified on the blank. Sample defects best suited to nanomachining repair are treated in detail: repairs are attempted, characterized using mask metrology and then tested for printability. Based on the initial results, the viability of repairing EUV blank native defects is discussed.

  9. Protein oxidation, UVA and human DNA repair.

    PubMed

    Karran, Peter; Brem, Reto

    2016-08-01

    Solar UVB is carcinogenic. Nucleotide excision repair (NER) counteracts the carcinogenicity of UVB by excising potentially mutagenic UVB-induced DNA lesions. Despite this capacity for DNA repair, non-melanoma skin cancers and apparently normal sun-exposed skin contain huge numbers of mutations that are mostly attributable to unrepaired UVB-induced DNA lesions. UVA is about 20-times more abundant than UVB in incident sunlight. It does cause some DNA damage but this does not fully account for its biological impact. The effects of solar UVA are mediated by its interactions with cellular photosensitizers that generate reactive oxygen species (ROS) and induce oxidative stress. The proteome is a significant target for damage by UVA-induced ROS. In cultured human cells, UVA-induced oxidation of DNA repair proteins inhibits DNA repair. This article addresses the possible role of oxidative stress and protein oxidation in determining DNA repair efficiency - with particular reference to NER and skin cancer risk.

  10. Phenotypic Transitions of Macrophages Orchestrate Tissue Repair

    PubMed Central

    Novak, Margaret L.; Koh, Timothy J.

    2014-01-01

    Macrophages are essential for the efficient healing of numerous tissues, and they contribute to impaired healing and fibrosis. Tissue repair proceeds through overlapping phases of inflammation, proliferation, and remodeling, and macrophages are present throughout this progression. Macrophages exhibit transitions in phenotype and function as tissue repair progresses, although the precise factors regulating these transitions remain poorly defined. In efficiently healing injuries, macrophages present during a given stage of repair appear to orchestrate transition into the next phase and, in turn, can promote debridement of the injury site, cell proliferation and angiogenesis, collagen deposition, and matrix remodeling. However, dysregulated macrophage function can contribute to failure to heal or fibrosis in several pathological situations. This review will address current knowledge of the origins and functions of macrophages during the progression of tissue repair, with emphasis on skin and skeletal muscle. Dysregulation of macrophages in disease states and therapies targeting macrophage activation to promote tissue repair are also discussed. PMID:24091222

  11. Systems Maintenance Automated Repair Tasks (SMART)

    NASA Technical Reports Server (NTRS)

    Schuh, Joseph; Mitchell, Brent; Locklear, Louis; Belson, Martin A.; Al-Shihabi, Mary Jo Y.; King, Nadean; Norena, Elkin; Hardin, Derek

    2010-01-01

    SMART is a uniform automated discrepancy analysis and repair-authoring platform that improves technical accuracy and timely delivery of repair procedures for a given discrepancy (see figure a). SMART will minimize data errors, create uniform repair processes, and enhance the existing knowledge base of engineering repair processes. This innovation is the first tool developed that links the hardware specification requirements with the actual repair methods, sequences, and required equipment. SMART is flexibly designed to be useable by multiple engineering groups requiring decision analysis, and by any work authorization and disposition platform (see figure b). The organizational logic creates the link between specification requirements of the hardware, and specific procedures required to repair discrepancies. The first segment in the SMART process uses a decision analysis tree to define all the permutations between component/ subcomponent/discrepancy/repair on the hardware. The second segment uses a repair matrix to define what the steps and sequences are for any repair defined in the decision tree. This segment also allows for the selection of specific steps from multivariable steps. SMART will also be able to interface with outside databases and to store information from them to be inserted into the repair-procedure document. Some of the steps will be identified as optional, and would only be used based on the location and the current configuration of the hardware. The output from this analysis would be sent to a work authoring system in the form of a predefined sequence of steps containing required actions, tools, parts, materials, certifications, and specific requirements controlling quality, functional requirements, and limitations.

  12. Recombinational repair of radiation-induced double-strand breaks occurs in the absence of extensive resection

    PubMed Central

    Westmoreland, James W.; Resnick, Michael A.

    2016-01-01

    Recombinational repair provides accurate chromosomal restitution after double-strand break (DSB) induction. While all DSB recombination repair models include 5′-3′ resection, there are no studies that directly assess the resection needed for repair between sister chromatids in G-2 arrested cells of random, radiation-induced ‘dirty’ DSBs. Using our Pulse Field Gel Electrophoresis-shift approach, we determined resection at IR-DSBs in WT and mutants lacking exonuclease1 or Sgs1 helicase. Lack of either reduced resection length by half, without decreased DSB repair or survival. In the exo1Δ sgs1Δ double mutant, resection was barely detectable, yet it only took an additional hour to achieve a level of repair comparable to WT and there was only a 2-fold dose-modifying effect on survival. Results with a Dnl4 deletion strain showed that remaining repair was not due to endjoining. Thus, similar to what has been shown for a single, clean HO-induced DSB, a severe reduction in resection tract length has only a modest effect on repair of multiple, dirty DSBs in G2-arrested cells. Significantly, this study provides the first opportunity to directly relate resection length at DSBs to the capability for global recombination repair between sister chromatids. PMID:26503252

  13. Recombinational repair of radiation-induced double-strand breaks occurs in the absence of extensive resection.

    PubMed

    Westmoreland, James W; Resnick, Michael A

    2016-01-29

    Recombinational repair provides accurate chromosomal restitution after double-strand break (DSB) induction. While all DSB recombination repair models include 5'-3' resection, there are no studies that directly assess the resection needed for repair between sister chromatids in G-2 arrested cells of random, radiation-induced 'dirty' DSBs. Using our Pulse Field Gel Electrophoresis-shift approach, we determined resection at IR-DSBs in WT and mutants lacking exonuclease1 or Sgs1 helicase. Lack of either reduced resection length by half, without decreased DSB repair or survival. In the exo1Δ sgs1Δ double mutant, resection was barely detectable, yet it only took an additional hour to achieve a level of repair comparable to WT and there was only a 2-fold dose-modifying effect on survival. Results with a Dnl4 deletion strain showed that remaining repair was not due to endjoining. Thus, similar to what has been shown for a single, clean HO-induced DSB, a severe reduction in resection tract length has only a modest effect on repair of multiple, dirty DSBs in G2-arrested cells. Significantly, this study provides the first opportunity to directly relate resection length at DSBs to the capability for global recombination repair between sister chromatids. PMID:26503252

  14. INTERNAL REPAIR OF PIPELINES REVIEW & EVALUATION OF INTERNAL PIPELINE REPAIR TRIALS REPORT

    SciTech Connect

    Robin Gordon; Bill Bruce; Ian Harris; Dennis Harwig; George Ritter; Bill Mohr; Matt Boring; Nancy Porter; Mike Sullivan; Chris Neary

    2004-09-01

    The two broad categories of fiber-reinforced composite liner repair and deposited weld metal repair technologies were reviewed and evaluated for potential application for internal repair of gas transmission pipelines. Both are used to some extent for other applications and could be further developed for internal, local, structural repair of gas transmission pipelines. Evaluation trials were conducted on pipe sections with simulated corrosion damage repaired with glass fiber-reinforced composite liners, carbon fiber-reinforced composite liners, and weld deposition. Additional un-repaired pipe sections were evaluated in the virgin condition and with simulated damage. Hydrostatic failure pressures for pipe sections repaired with glass fiber-reinforced composite liner were only marginally greater than that of pipe sections without liners, indicating that this type of liner is generally ineffective at restoring the pressure containing capabilities of pipelines. Failure pressure for pipe repaired with carbon fiber-reinforced composite liner was greater than that of the un-repaired pipe section with damage, indicating that this type of liner is effective at restoring the pressure containing capability of pipe. Pipe repaired with weld deposition failed at pressures lower than that of un-repaired pipe in both the virgin and damaged conditions, indicating that this repair technology is less effective at restoring the pressure containing capability of pipe than a carbon fiber-reinforced liner repair. Physical testing indicates that carbon fiber-reinforced liner repair is the most promising technology evaluated to-date. Development of a comprehensive test plan for this process is recommended for use in the next phase of this project.

  15. Repair of UV damaged DNA, genes and proteins of yeast and human

    SciTech Connect

    Prakash, L.

    1991-04-01

    Our objectives are to determine the molecular mechanism of the incision step of excision repair of ultraviolet (UV) light damaged DNA in eukaryotic organisms, using the yeast Saccharomyces cerevisiae as a model system, as well as studying the human homologs of yeast excision repair and postreplication repair proteins. In addition to its single-stranded DNA-dependent A TPase and DNA helicase activities, we have found that RAD3 protein also possesses DNA-RNA helicase activity, and that like RAD3, the Schizosaccharomyces pombe RAD3 homolog, rhp3{sup +}, is an essential gene. We have overexpressed the human RAD3 homolog, ERCC2, in yeast to facilitate its purification. The RAD10 protein was purified to homogeneity and shown to bind DNA. ERCC3y, the yeast homolog of the human ERCC-3/XP-B gene, has been sequenced and shown to be essential for viability. The Drosophila and human homologs of RAD6, required for postreplication repair and UV induced mutagenesis, were shown to complement the rad6 {Delta} mutation of yeast. Since defective DNA repair and enhanced neoplasia characterize several human genetic diseases, and repair proteins are highly conserved between yeast and man, a thorough understanding of the molecular mechanisms of DNA repir in yeast should provide a better understanding of the causes of carcinogenesis.

  16. Hodgkin Lymphoma Risk: Role of Genetic Polymorphisms and Gene-Gene Interactions in DNA repair pathways

    PubMed Central

    Monroy, Claudia M.; Cortes, Andrea C.; Lopez, Mirtha; Rourke, Elizabeth; Etzel, Carol J.; Younes, Anas; Strom, Sara S.; El-Zein, Randa

    2011-01-01

    DNA repair variants may play a potentially important role in an individual’s susceptibility to developing cancer. Numerous studies have reported the association between genetic single nucleotide polymorphisms (SNPs) in DNA repair genes and different types of hematologic cancers. However, to date, the effects of such SNPs on modulating Hodgkin Lymphoma (HL) risk have not yet been investigated. We hypothesized that gene-gene interaction between candidate genes in Direct Reversal, Nucleotide excision repair (NER), Base excision repair (BER) and Double strand break (DSB) pathways may contribute to susceptibility to HL. To test this hypothesis, we conducted a study on 200 HL cases and 220 controls to assess associations between HL risk and 21 functional SNPs in DNA repair genes. We evaluated potential gene-gene interactions and the association of multiple polymorphisms in a chromosome region using a multi-analytic strategy combining logistic regression, multi-factor dimensionality reduction and classification and regression tree approaches. We observed that, in combination, allelic variants in the XPC Ala499Val, NBN Glu185Gln, XRCC3 Thr241Me, XRCC1 Arg194Trp and XRCC1 399Gln polymorphisms modify the risk for developing HL. Moreover, the cumulative genetic risk score revealed a significant trend where the risk for developing HL increases as the number of adverse alleles in BER and DSB genes increase. These findings suggest that DNA repair variants in BER and DSB pathways may play an important role in the development of HL. PMID:21374732

  17. Loss of Urokinase Receptor Sensitizes Cells to DNA Damage and Delays DNA Repair

    PubMed Central

    Narayanaswamy, Pavan B.; Hodjat, Mahshid; Haller, Hermann; Dumler, Inna; Kiyan, Yulia

    2014-01-01

    DNA damage induced by numerous exogenous or endogenous factors may have irreversible consequences on the cell leading to cell cycle arrest, senescence and cell death. The DNA damage response (DDR) is powerful signaling machinery triggered in response to DNA damage, to provide DNA damage recognition, signaling and repair. Most anticancer drugs induce DNA damage, and DNA repair in turn attenuates therapeutic efficiency of those drugs. Approaches delaying DNA repair are often used to increase efficiency of treatment. Recent data show that ubiquitin-proteasome system is essential for signaling and repair of DNA damage. However, mechanisms providing regulation of proteasome intracellular localization, activity, and recruitment to DNA damage sites are elusive. Even less investigated are the roles of extranuclear signaling proteins in these processes. In this study, we report the involvement of the serine protease urokinase-type plasminogen activator receptor (uPAR) in DDR-associated regulation of proteasome. We show that in vascular smooth muscle cells (VSMC) uPAR activates DNA single strand break repair signaling pathway. We provide evidence that uPAR is essential for functional assembly of the 26S proteasome. We further demonstrate that uPAR mediates DNA damage-induced phosphorylation, nuclear import, and recruitment of the regulatory subunit PSMD6 to proteasome. We found that deficiency of uPAR and PSMD6 delays DNA repair and leads to decreased cell survival. These data may offer new therapeutic approaches for diseases such as cancer, cardiovascular and neurodegenerative disorders. PMID:24987841

  18. Hiatal hernia repair with biologic mesh reinforcement reduces recurrence rate in small hiatal hernias.

    PubMed

    Schmidt, E; Shaligram, A; Reynoso, J F; Kothari, V; Oleynikov, D

    2014-01-01

    The utility of mesh reinforcement for small hiatal hernia found especially during antireflux surgery is unknown. Initial reports for the use of biological mesh for crural reinforcement during repair for defects greater than 5 cm have been shown to decrease recurrence rates. This study compares patients with small hiatal hernias who underwent onlay biologic mesh buttress repair versus those with suture cruroplasty alone. This is a single-institution retrospective review of all patients undergoing repair of hiatal hernia measuring 1-5 cm between 2002 and 2009. The patients were evaluated based on surgical repair: one group undergoing crural reinforcement with onlay biologic mesh and other group with suture cruroplasty only. Seventy patients with hiatal hernia measuring 1-5 cm were identified. Thirty-eight patients had hernia repair with biologic mesh, and 32 patients had repair with suture cruroplasty only. Recurrence rate at 1 year was 16% (5/32) in patients who had suture cruroplasty only and 0% (0/38) in the group with crural reinforcement with absorbable mesh (statistically significant, P = 0.017). Suture cruroplasty alone appears to be inadequate for hiatal hernias measuring 1-5 cm with significant recurrence rate and failure of antireflux surgery. Crural reinforcement with absorbable mesh may reduce hiatal hernia recurrence rate in small hiatal hernias.

  19. Outcomes of repair of left partial anomalous pulmonary venous connection in children.

    PubMed

    Naimo, Phillip S; d'Udekem, Yves; Brizard, Christian P; Konstantinov, Igor E

    2015-08-01

    Herein, we report a case series of patients who underwent repair of left partial anomalous pulmonary venous connection (L-PAPVC) via anastomosing the anomalous pulmonary vein (PV) to the left atrial appendage. Fifteen children underwent repair of L-PAPVC between 1980 and 2014. The median age at surgery was 3.6 years (range: 5 days to 17.2 years). Concomitant anomalies were present in 87% (13/15). There were no early deaths. There was 1 late death occurring 63 days following surgical repair due to pneumococcal septicaemia in a patient with prior atrial septal defect closure and Ehlers-Danlos syndrome. The overall survival rate was 93.7% at 15 years. A single patient (1/15, 7%) required reoperation 1 year after L-PAPVC repair for PV stenosis due to several thrombi located throughout the PV. The rate of freedom from PV reoperation was 90% at 10 years. The follow-up was 100% complete with a median time of 11 years (range: 52 days to 20 years). To our knowledge, this is the youngest cohort of patients who have undergone surgical repair of L-PAPVC. Repair of L-PAPVC in children can be achieved via anastomosis of the anomalous vessel to the left atrial (LA) with excellent outcomes. The rate of anastomotic stenosis at the site of implantation on the LA is low. PMID:25980772

  20. Crystal Structures of DNA-Whirly Complexes and Their Role in Arabidopsis Organelle Genome Repair

    SciTech Connect

    Cappadocia, Laurent; Maréchal, Alexandre; Parent, Jean-Sébastien; Lepage, Étienne; Sygusch, Jurgen; Brisson, Normand

    2010-09-07

    DNA double-strand breaks are highly detrimental to all organisms and need to be quickly and accurately repaired. Although several proteins are known to maintain plastid and mitochondrial genome stability in plants, little is known about the mechanisms of DNA repair in these organelles and the roles of specific proteins. Here, using ciprofloxacin as a DNA damaging agent specific to the organelles, we show that plastids and mitochondria can repair DNA double-strand breaks through an error-prone pathway similar to the microhomology-mediated break-induced replication observed in humans, yeast, and bacteria. This pathway is negatively regulated by the single-stranded DNA (ssDNA) binding proteins from the Whirly family, thus indicating that these proteins could contribute to the accurate repair of plant organelle genomes. To understand the role of Whirly proteins in this process, we solved the crystal structures of several Whirly-DNA complexes. These reveal a nonsequence-specific ssDNA binding mechanism in which DNA is stabilized between domains of adjacent subunits and rendered unavailable for duplex formation and/or protein interactions. Our results suggest a model in which the binding of Whirly proteins to ssDNA would favor accurate repair of DNA double-strand breaks over an error-prone microhomology-mediated break-induced replication repair pathway.