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Sample records for single rad52 repair

  1. A novel allele of Saccharomyces cerevisiae RFA1 that is deficient in recombination and repair and suppressible by RAD52.

    PubMed Central

    Firmenich, A A; Elias-Arnanz, M; Berg, P

    1995-01-01

    To understand the mechanisms involved in homologous recombination, we have performed a search for Saccharomyces cerevisiae mutants unable to carry out plasmid-to-chromosome gene conversion. For this purpose, we have developed a colony color assay in which recombination is induced by the controlled delivery of double-strand breaks (DSBs). Recombination occurs between a chromosomal mutant ade2 allele and a second plasmid-borne ade2 allele where DSBs are introduced via the site-specific HO endonuclease. Besides isolating a number of new alleles in known rad genes, we identified a novel allele of the RFA1 gene, rfa1-44, which encodes the large subunit of the heterotrimeric yeast single-stranded DNA-binding protein RPA. Characterization of rfa1-44 revealed that it is, like members of the RAD52 epistasis group, sensitive to X rays, high doses of UV, and HO-induced DSBs. In addition, rfa1-44 shows a reduced ability to undergo sporulation and HO-induced gene conversion. The mutation was mapped to a single-base substitution resulting in an aspartate at amino acid residue 77 instead of glycine. Moreover, all radiation sensitivities and repair defects of rfa1-44 are suppressed by RAD52 in a dose-dependent manner, and one RAD52 mutant allele, rad52-34, displays nonallelic noncomplementation when crossed with rfa1-44. Presented is a model accounting for this genetic interaction in which Rfa1, in a complex with Rad52, serves to assemble other proteins of the recombination-repair machinery at the site of DSBs and other kinds of DNA damage. We believe that our findings and those of J. Smith and R. Rothstein (Mol. Cell. Biol. 15:1632-1641, 1995) are the first in vivo demonstrations of the involvement of a eukaryotic single-stranded binding protein in recombination and repair processes. PMID:7862153

  2. Mammalian RAD52 Functions in Break-Induced Replication Repair of Collapsed DNA Replication Forks.

    PubMed

    Sotiriou, Sotirios K; Kamileri, Irene; Lugli, Natalia; Evangelou, Konstantinos; Da-Ré, Caterina; Huber, Florian; Padayachy, Laura; Tardy, Sebastien; Nicati, Noemie L; Barriot, Samia; Ochs, Fena; Lukas, Claudia; Lukas, Jiri; Gorgoulis, Vassilis G; Scapozza, Leonardo; Halazonetis, Thanos D

    2016-12-15

    Human cancers are characterized by the presence of oncogene-induced DNA replication stress (DRS), making them dependent on repair pathways such as break-induced replication (BIR) for damaged DNA replication forks. To better understand BIR, we performed a targeted siRNA screen for genes whose depletion inhibited G1 to S phase progression when oncogenic cyclin E was overexpressed. RAD52, a gene dispensable for normal development in mice, was among the top hits. In cells in which fork collapse was induced by oncogenes or chemicals, the Rad52 protein localized to DRS foci. Depletion of Rad52 by siRNA or knockout of the gene by CRISPR/Cas9 compromised restart of collapsed forks and led to DNA damage in cells experiencing DRS. Furthermore, in cancer-prone, heterozygous APC mutant mice, homozygous deletion of the Rad52 gene suppressed tumor growth and prolonged lifespan. We therefore propose that mammalian RAD52 facilitates repair of collapsed DNA replication forks in cancer cells.

  3. 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

  4. Enhancing CRISPR/Cas9-mediated homology-directed repair in mammalian cells by expressing Saccharomyces cerevisiae Rad52.

    PubMed

    Shao, Simin; Ren, Chonghua; Liu, Zhongtian; Bai, Yichun; Chen, Zhilong; Wei, Zehui; Wang, Xin; Zhang, Zhiying; Xu, Kun

    2017-09-18

    Precise genome editing with desired point mutations can be generated by CRISPR/Cas9-mediated homology-directed repair (HDR) and is of great significance for gene function study, gene therapy and animal breeding. However, HDR efficiency is inherently low and improvements are necessitated. Herein, we determined that the HDR efficiency could be enhanced by expressing Rad52, a gene that is involved in the homologous recombination process. Both the Rad52 co-expression and Rad52-Cas9 fusion strategies yielded approximately 3-fold increase in HDR during the surrogate reporter assays in human HEK293T cells, as well as in the genome editing assays. Moreover, the enhancement effects of the Rad52-Cas9 fusion on HDR mediated by different (plasmid, PCR and ssDNA) donor templates were confirmed. We found that the HDR efficiency could be significantly improved to about 40% by the combined usage of Rad52 and Scr7. In addition, we also applied the fusion strategy for modifying the IGF2 gene of porcine PK15 cells, which further demonstrated a 2.2-fold increase in HDR frequency. In conclusion, our data suggests that Rad52-Cas9 fusion is a good option for enhancing CRISPR/Cas9-mediated HDR, which may be of use in future studies involving precise genome editing. Copyright © 2017 Elsevier Ltd. All rights reserved.

  5. DNA annealing by Rad52 Protein is stimulated by specific interaction with the complex of replication protein A and single-stranded DNA

    PubMed Central

    Sugiyama, Tomohiko; New, James H.; Kowalczykowski, Stephen C.

    1998-01-01

    Homologous recombination in Saccharomyces cerevisiae depends critically on RAD52 function. In vitro, Rad52 protein preferentially binds single-stranded DNA (ssDNA), mediates annealing of complementary ssDNA, and stimulates Rad51 protein-mediated DNA strand exchange. Replication protein A (RPA) is a ssDNA-binding protein that is also crucial to the recombination process. Herein we report that Rad52 protein effects the annealing of RPA–ssDNA complexes, complexes that are otherwise unable to anneal. The ability of Rad52 protein to promote annealing depends on both the type of ssDNA substrate and ssDNA binding protein. RPA allows, but slows, Rad52 protein-mediated annealing of oligonucleotides. In contrast, RPA is almost essential for annealing of longer plasmid-sized DNA but has little effect on the annealing of poly(dT) and poly(dA), which are relatively long DNA molecules free of secondary structure. These results suggest that one role of RPA in Rad52 protein-mediated annealing is the elimination of DNA secondary structure. However, neither Escherichia coli ssDNA binding protein nor human RPA can substitute in this reaction, indicating that RPA has a second role in this process, a role that requires specific RPA–Rad52 protein interactions. This idea is confirmed by the finding that RPA, which is complexed with nonhomologous ssDNA, inhibits annealing but the human RPA–ssDNA complex does not. Finally, we present a model for the early steps of the repair of double-strand DNA breaks in yeast. PMID:9600915

  6. 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.

  7. The Saccharomyces cerevisiae DNA recombination and repair functions of the RAD52 epistasis group inhibit Ty1 transposition.

    PubMed Central

    Rattray, A J; Shafer, B K; Garfinkel, D J

    2000-01-01

    RNA transcribed from the Saccharomyces cerevisiae retrotransposon Ty1 accumulates to a high level in mitotically growing haploid cells, yet transposition occurs at very low frequencies. The product of reverse transcription is a linear double-stranded DNA molecule that reenters the genome by either Ty1-integrase-mediated insertion or homologous recombination with one of the preexisting genomic Ty1 (or delta) elements. Here we examine the role of the cellular homologous recombination functions on Ty1 transposition. We find that transposition is elevated in cells mutated for genes in the RAD52 recombinational repair pathway, such as RAD50, RAD51, RAD52, RAD54, or RAD57, or in the DNA ligase I gene CDC9, but is not elevated in cells mutated in the DNA repair functions encoded by the RAD1, RAD2, or MSH2 genes. The increase in Ty1 transposition observed when genes in the RAD52 recombinational pathway are mutated is not associated with a significant increase in Ty1 RNA or proteins. However, unincorporated Ty1 cDNA levels are markedly elevated. These results suggest that members of the RAD52 recombinational repair pathway inhibit Ty1 post-translationally by influencing the fate of Ty1 cDNA. PMID:10655210

  8. A novel allele of RAD52 that causes severe DNA repair and recombination deficiencies only in the absence of RAD51 or RAD59.

    PubMed Central

    Bai, Y; Davis, A P; Symington, L S

    1999-01-01

    With the use of an intrachromosomal inverted repeat as a recombination reporter, we have shown that mitotic recombination is dependent on the RAD52 gene, but reduced only fivefold by mutation of RAD51. RAD59, a component of the RAD51-independent pathway, was identified previously by screening for mutations that reduced inverted-repeat recombination in a rad51 strain. Here we describe a rad52 mutation, rad52R70K, that also reduced recombination synergistically in a rad51 background. The phenotype of the rad52R70K strain, which includes weak gamma-ray sensitivity, a fourfold reduction in the rate of inverted-repeat recombination, elevated allelic recombination, sporulation proficiency, and a reduction in the efficiency of mating-type switching and single-strand annealing, was similar to that observed for deletion of the RAD59 gene. However, rad52R70K rad59 double mutants showed synergistic defects in ionizing radiation resistance, sporulation, and mating-type switching. These results suggest that Rad52 and Rad59 have partially overlapping functions and that Rad59 can substitute for this function of Rad52 in a RAD51 rad52R70K strain. PMID:10545446

  9. Histone H3K56 Acetylation, Rad52, and Non-DNA Repair Factors Control Double-Strand Break Repair Choice with the Sister Chromatid

    PubMed Central

    Rothstein, Rodney; Aguilera, Andrés

    2013-01-01

    DNA double-strand breaks (DSBs) are harmful lesions that arise mainly during replication. The choice of the sister chromatid as the preferential repair template is critical for genome integrity, but the mechanisms that guarantee this choice are unknown. Here we identify new genes with a specific role in assuring the sister chromatid as the preferred repair template. Physical analyses of sister chromatid recombination (SCR) in 28 selected mutants that increase Rad52 foci and inter-homolog recombination uncovered 8 new genes required for SCR. These include the SUMO/Ub-SUMO protease Wss1, the stress-response proteins Bud27 and Pdr10, the ADA histone acetyl-transferase complex proteins Ahc1 and Ada2, as well as the Hst3 and Hst4 histone deacetylase and the Rtt109 histone acetyl-transferase genes, whose target is histone H3 Lysine 56 (H3K56). Importantly, we use mutations in H3K56 residue to A, R, and Q to reveal that H3K56 acetylation/deacetylation is critical to promote SCR as the major repair mechanism for replication-born DSBs. The same phenotype is observed for a particular class of rad52 alleles, represented by rad52-C180A, with a DSB repair defect but a spontaneous hyper-recombination phenotype. We propose that specific Rad52 residues, as well as the histone H3 acetylation/deacetylation state of chromatin and other specific factors, play an important role in identifying the sister as the choice template for the repair of replication-born DSBs. Our work demonstrates the existence of specific functions to guarantee SCR as the main repair event for replication-born DSBs that can occur by two pathways, one Rad51-dependent and the other Pol32-dependent. A dysfunction can lead to genome instability as manifested by high levels of homolog recombination and DSB accumulation. PMID:23357952

  10. Homologous and homeologous intermolecular gene conversion are not differentially affected by mutations in the DNA damage or the mismatch repair genes RAD1, RAD50, RAD51, RAD52, RAD54, PMS1 and MSH2

    SciTech Connect

    Porter, G.; Westmoreland, J.; Priebe, S.

    1996-06-01

    Mismatch repair (MMR) genes or genes involved in both DNA damage repair and homologous recombination might affect homeologous vs. homologous recombination differentially. Spontaneous mitotic gene conversion between a chromosome and a homologous or homeologous donor sequence (14% diverged) on a single copy plasmid was examined in wild-type Saccharomyces cerevisiae strains and in MMR or DNA damage repair mutants. Homologous recombination in rad51, rad52 and rad54 mutants was considerably reduced, while there was little effect of rad1, rad50, pms1 and msh2 null mutations. DNA divergence resulted in no differential effect on recombination rates in the wild type or the mutants; there was only a five- to 10-fold reduction in homeologous relative to homologous recombination regardless of background. Since DNA divergence is known to affect recombination in some systems, we propose that differences in the role of MMR depends on the mode of recombination and/or the level of divergence. Based on analysis of the recombination breakpoints, there is a minimum of three homologous bases required at a recombination junction. A comparison of Rad{sup +} vs. rad52 strains revealed that while all conversion tracts are continuous, elimination of RAD52 leads to the appearance of a novel class of very short conversion tracts. 67 refs., 5 figs., 4 tabs.

  11. Homologous and Homeologous Intermolecular Gene Conversion Are Not Differentially Affected by Mutations in the DNA Damage or the Mismatch Repair Genes Rad1, Rad50, Rad51, Rad52, Rad54, Pms1 and Msh2

    PubMed Central

    Porter, G.; Westmoreland, J.; Priebe, S.; Resnick, M. A.

    1996-01-01

    Mismatch repair (MMR) genes or genes involved in both DNA damage repair and homologous recombination might affect homeologous vs. homologous recombination differentially. Spontaneous mitotic gene conversion between a chromosome and a homologous or homeologous donor sequence (14% diverged) on a single copy plasmid was examined in wild-type Saccharomyces cerevisiae strains and in MMR or DNA damage repair mutants. Homologous recombination in rad51, rad52 and rad54 mutants was considerably reduced, while there was little effect of rad1, rad50, pms1 and msh2 null mutations. DNA divergence resulted in no differential effect on recombination rates in the wild type or the mutants; there was only a five- to 10-fold reduction in homeologous relative to homologous recombination regardless of background. Since DNA divergence is known to affect recombination in some systems, we propose that differences in the role of MMR depends on the mode of recombination and/or the level of divergence. Based on analysis of the recombination breakpoints, there is a minimum of three homologous bases required at a recombination junction. A comparison of Rad(+) vs. rad52 strains revealed that while all conversion tracts are continuous, elimination of RAD52 leads to the appearance of a novel class of very short conversion tracts. PMID:8725224

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

    PubMed Central

    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.

    2016-01-01

    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

  13. 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

  14. Mgm101: A double-duty Rad52-like protein

    PubMed Central

    Rendeková, Jana; Šimoničová, Lucia; Thomas, Peter H.; McHugh, Peter J.; Chovanec, Miroslav

    2016-01-01

    ABSTRACT Mgm101 has well-characterized activity for the repair and replication of the mitochondrial genome. Recent work has demonstrated a further role for Mgm101 in nuclear DNA metabolism, contributing to an S-phase specific DNA interstrand cross-link repair pathway that acts redundantly with a pathway controlled by Pso2 exonuclease. Due to involvement of FANCM, FANCJ and FANCP homologues (Mph1, Chl1 and Slx4), this pathway has been described as a Fanconi anemia-like pathway. In this pathway, Mgm101 physically interacts with the DNA helicase Mph1 and the MutSα (Msh2/Msh6) heterodimer, but its precise role is yet to be elucidated. Data presented here suggests that Mgm101 functionally overlaps with Rad52, supporting previous suggestions that, based on protein structure and biochemical properties, Mgm101 and Rad52 belong to a family of proteins with similar function. In addition, our data shows that this overlap extends to the function of both proteins at telomeres, where Mgm101 is required for telomere elongation during chromosome replication in rad52 defective cells. We hypothesize that Mgm101 could, in Rad52-like manner, preferentially bind single-stranded DNAs (such as at stalled replication forks, broken chromosomes and natural chromosome ends), stabilize them and mediate single-strand annealing-like homologous recombination event to prevent them from converting into toxic structures. PMID:27636878

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

    PubMed Central

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

    2015-01-01

    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. PMID:26540255

  16. The rad52-Y66A allele alters the choice of donor template during spontaneous chromosomal recombination.

    PubMed

    de Mayolo, Adriana Antúnez; Sunjevaric, Ivana; Reid, Robert; Mortensen, Uffe H; Rothstein, Rodney; Lisby, Michael

    2010-01-02

    Spontaneous mitotic recombination is a potential source of genetic changes such as loss of heterozygosity and chromosome translocations, which may lead to genetic disease. In this study we have used a rad52 hyper-recombination mutant, rad52-Y66A, to investigate the process of spontaneous heteroallelic recombination in the yeast Saccharomyces cerevisiae. We find that spontaneous recombination has different genetic requirements, depending on whether the recombination event occurs between chromosomes or between chromosome and plasmid sequences. The hyper-recombination phenotype of the rad52-Y66A mutation is epistatic with deletion of MRE11, which is required for establishment of DNA damage-induced cohesion. Moreover, single-cell analysis of strains expressing YFP-tagged Rad52-Y66A reveals a close to wild-type frequency of focus formation, but with foci lasting 6 times longer. This result suggests that spontaneous DNA lesions that require recombinational repair occur at the same frequency in wild-type and rad52-Y66A cells, but that the recombination process is slow in rad52-Y66A cells. Taken together, we propose that the slow recombinational DNA repair in the rad52-Y66A mutant leads to a by-pass of the window-of-opportunity for sister chromatid recombination normally promoted by MRE11-dependent damage-induced cohesion thereby causing a shift towards interchromosomal recombination.

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

    PubMed

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

    2016-09-14

    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.

  18. 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

  19. 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

  20. 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

  1. 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.

  2. Enhancement of gene targeting in human cells by intranuclear permeation of the Saccharomyces cerevisiae Rad52 protein

    PubMed Central

    Kalvala, Arjun; Rainaldi, Giuseppe; Di Primio, Cristina; Liverani, Vania; Falaschi, Arturo; Galli, Alvaro

    2010-01-01

    The introduction of exogenous DNA in human somatic cells results in a frequency of random integration at least 100-fold higher than gene targeting (GT), posing a seemingly insurmountable limitation for gene therapy applications. We previously reported that, in human cells, the stable over-expression of the Saccharomyces cerevisiae Rad52 gene (yRAD52), which plays the major role in yeast homologous recombination (HR), caused an up to 37-fold increase in the frequency of GT, indicating that yRAD52 interacts with the double-strand break repair pathway(s) of human cells favoring homologous integration. In the present study, we tested the effect of the yRad52 protein by delivering it directly to the human cells. To this purpose, we fused the yRAD52 cDNA to the arginine-rich domain of the TAT protein of HIV (tat11) that is known to permeate the cell membranes. We observed that a recombinant yRad52tat11 fusion protein produced in Escherichia coli, which maintains its ability to bind single-stranded DNA (ssDNA), enters the cells and the nuclei, where it is able to increase both intrachromosomal recombination and GT up to 63- and 50-fold, respectively. Moreover, the non-homologous plasmid DNA integration decreased by 4-fold. yRAD52tat11 proteins carrying point mutations in the ssDNA binding domain caused a lower or nil increase in recombination proficiency. Thus, the yRad52tat11 could be instrumental to increase GT in human cells and a ‘protein delivery approach’ offers a new tool for developing novel strategies for genome modification and gene therapy applications. PMID:20519199

  3. 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

  4. Rad52 competes with Ku70/Ku86 for binding to S-region DSB ends to modulate antibody class-switch DNA recombination.

    PubMed

    Zan, Hong; Tat, Connie; Qiu, Zhifang; Taylor, Julia R; Guerrero, Justin A; Shen, Tian; Casali, Paolo

    2017-02-08

    Antibody class-switch DNA recombination (CSR) is initiated by AID-introduced DSBs in the switch (S) regions targeted for recombination, as effected by Ku70/Ku86-mediated NHEJ. Ku-deficient B cells, however, undergo (reduced) CSR through an alternative(A)-NHEJ pathway, which introduces microhomologies in S-S junctions. As microhomology-mediated end-joining requires annealing of single-strand DNA ends, we addressed the contribution of single-strand annealing factors HR Rad52 and translesion DNA polymerase θ to CSR. Compared with their Rad52(+/+) counterparts, which display normal CSR, Rad52(-/-) B cells show increased CSR, fewer intra-Sμ region recombinations, no/minimal microhomologies in S-S junctions, decreased c-Myc/IgH translocations and increased Ku70/Ku86 recruitment to S-region DSB ends. Rad52 competes with Ku70/Ku86 for binding to S-region DSB ends. It also facilitates a Ku-independent DSB repair, which favours intra-S region recombination and mediates, particularly in Ku absence, inter-S-S recombination, as emphasized by the significantly greater CSR reduction in Rad52(-/-) versus Rad52(+/+) B cells on Ku86 knockdown.

  5. Rad52 competes with Ku70/Ku86 for binding to S-region DSB ends to modulate antibody class-switch DNA recombination

    PubMed Central

    Zan, Hong; Tat, Connie; Qiu, Zhifang; Taylor, Julia R.; Guerrero, Justin A.; Shen, Tian; Casali, Paolo

    2017-01-01

    Antibody class-switch DNA recombination (CSR) is initiated by AID-introduced DSBs in the switch (S) regions targeted for recombination, as effected by Ku70/Ku86-mediated NHEJ. Ku-deficient B cells, however, undergo (reduced) CSR through an alternative(A)-NHEJ pathway, which introduces microhomologies in S–S junctions. As microhomology-mediated end-joining requires annealing of single-strand DNA ends, we addressed the contribution of single-strand annealing factors HR Rad52 and translesion DNA polymerase θ to CSR. Compared with their Rad52+/+ counterparts, which display normal CSR, Rad52−/− B cells show increased CSR, fewer intra-Sμ region recombinations, no/minimal microhomologies in S–S junctions, decreased c-Myc/IgH translocations and increased Ku70/Ku86 recruitment to S-region DSB ends. Rad52 competes with Ku70/Ku86 for binding to S-region DSB ends. It also facilitates a Ku-independent DSB repair, which favours intra-S region recombination and mediates, particularly in Ku absence, inter-S–S recombination, as emphasized by the significantly greater CSR reduction in Rad52−/− versus Rad52+/+ B cells on Ku86 knockdown. PMID:28176781

  6. Potentiation of gene targeting in human cells by expression of Saccharomyces cerevisiae Rad52

    PubMed Central

    Di Primio, Cristina; Galli, Alvaro; Cervelli, Tiziana; Zoppè, Monica; Rainaldi, Giuseppe

    2005-01-01

    When exogenous DNA is stably introduced in mammalian cells, it is typically integrated in random positions, and only a minor fraction enters a pathway of homologous recombination (HR). The complex Rad51/Rad52 is a major player in the management of exogenous DNA in eukaryotic organisms and plays a critical role in the choice of repair system. In Saccharomyces cerevisiae, the pathway of choice is HR, mediated by Rad52 (ScRad52), which differs slightly from its human homologue. Here, we present an approach that utilizes ScRad52 to enhance HR in human cells containing a specific substrate for recombination. Clones of HeLa cells were produced expressing functional ScRad52. These cells showed enhanced resistance to DNA damaging treatments and revealed a different distribution of Rad51 foci (a marker of recombination complex formation). More significantly, ScRad52 expression resulted in an up to 37-fold increase in gene targeting by HR. In the same cells, random integration of exogenous DNA was significantly reduced, consistent with the view that HR and non-homologous end joining are alternative competing pathways. Expression of ScRad52 could offer a major improvement for experiments requiring gene targeting by HR, both in basic research and in gene therapy studies. PMID:16106043

  7. Giardia duodenalis Rad52 protein: biochemical characterization and response upon DNA damage.

    PubMed

    Martínez-Miguel, Rosa María; Sandoval-Cabrera, Antonio; Bazán-Tejeda, María Luisa; Torres-Huerta, Ana Laura; Martínez-Reyes, Diego A; Bermúdez-Cruz, Rosa María

    2017-08-01

    Giardia duodenalis is a flagellated binucleated protozoan that colonizes the small intestine in mammals, causing giardiasis, acute or chronic diarrhea. DNA double strand break either endogenously or exogenously generated is a major insult to DNA and its repair by homologous recombination (HR) is crucial for genomic stability. During HR, Rad52 plays key roles in the loading of the Rad51 recombinase, and the annealing of the second double-strand break end to the displaced strand of the D-loop structure. Among the functions found in vitro in yeast and human Rad52 protein are: ssDNA or dsDNA binding activity, ability to anneal bare or RPA coated-ssDNA, as well as multimeric ring formation. In this work, we searched for conserved domains in a putative Rad52 protein from G. duodenalis (GdRad52). Its coding sequence was cloned, expressed and purified to study its biochemical properties. rGdRad52 binds to dsDNA and ssDNA, with greater affinity for the latter. Likewise, rGdRad52 promotes annealing of DNA uncoated and coated with GdRPA1. rGdRad52 interacts with GdDMC1B and with GdRPA1 protein as shown in far western blotting assay. Additionally, rGdRad52 formed multimeric rings as observed by electronic microscopy. Finally, GdRad52 is over expressed in response upon DNA damage inflicted on trophozoites. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

  8. 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

  9. 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.

  10. Functional characterization of RAD52 as a lung cancer susceptibility gene in the 12p13.33 locus

    PubMed Central

    Lieberman, Rachel; Xiong, Donghai; James, Michael; Han, Younghun; Amos, Christopher I.; Wang, Liang; You, Ming

    2015-01-01

    Recent genome-wide association studies have identified variations in the recombination repair gene, RAD52, that are associated with increased lung cancer risk, and particularly with the development of lung squamous cell carcinomas (LUSC). LUSC development is strongly associated with smoking. DNA repair is increased in the lung tissues of smokers, presumably because of ongoing DNA damage from exposure to tobacco smoke. A key player in the DNA damage response, RAD52 plays a role in DNA strand exchange and annealing during homologous recombination (HR) in mammalian cells. In this study, we discovered two cis-expression quantitative trait loci (eQTL) SNPs in the RAD52 gene that are associated with its expression and are also associated with LUSC risk. In addition, we report that amplification of the genomic region 12p13.33, which contains the RAD52 gene, is significantly associated with the development of LUSC in the TCGA database and that somatic overexpression of RAD52 was confirmed to be significant in LUSC tumors from our own patient cohort. Consistent with these genetic findings, we demonstrate that blockade of Rad52 slows cell growth and induces senescence in mouse bronchial epithelial cells. In contrast, overexpression of Rad52 leads to an increased rate of cell proliferation. We show that depletion of Rad52 in mouse lung tumor cells alters cell cycle distribution and increases DNA damage accumulation associated with increased tumor cell death. Our genetic and functional data implicate RAD52 as a significant determinant of risk in the development of LUSC. PMID:26013599

  11. Rad1, rad10 and rad52 mutations reduce the increase of microhomology length during radiation-induced microhomology-mediated illegitimate recombination in saccharomyces cerevisiae.

    PubMed

    Chan, Cecilia Y; Schiestl, Robert H

    2009-08-01

    Abstract Illegitimate recombination can repair DNA double-strand breaks in one of two ways, either without sequence homology or by using a few base pairs of homology at the junctions. The second process is known as microhomology-mediated recombination. Previous studies showed that ionizing radiation and restriction enzymes increase the frequency of microhomology-mediated recombination in trans during rejoining of unirradiated plasmids or during integration of plasmids into the genome. Here we show that radiation-induced microhomology-mediated recombination is reduced by deletion of RAD52, RAD1 and RAD10 but is not affected by deletion of RAD51 and RAD2. The rad52 mutant did not change the frequency of radiation-induced microhomology-mediated recombination but rather reduced the length of microhomology required to undergo repair during radiation-induced recombination. The rad1 and rad10 mutants exhibited a smaller increase in the frequency of radiation-induced microhomology-mediated recombination, and the radiation-induced integration junctions from these mutants did not show more than 4 bp of microhomology. These results suggest that Rad52 facilitates annealing of short homologous sequences during integration and that Rad1/Rad10 endonuclease mediates removal of the displaced 3' single-stranded DNA ends after base-pairing of microhomology sequences, when more than 4 bp of microhomology are used. Taken together, these results suggest that radiation-induced microhomology-mediated recombination is under the same genetic control as the single-strand annealing apparatus that requires the RAD52, RAD1 and RAD10 genes.

  12. Nuclear oscillations and nuclear filament formation accompany single-strand annealing repair of a dicentric chromosome in Saccharomyces cerevisiae.

    PubMed

    Thrower, Douglas A; Stemple, Jennifer; Yeh, Elaine; Bloom, Kerry

    2003-02-01

    Dicentric chromosomes undergo breakage during mitosis as a result of the attachment of two centromeres on one sister chromatid to opposite spindle poles. Studies utilizing a conditional dicentric chromosome III in Saccharomyces cerevisiae have shown that dicentric chromosome repair occurs primarily by deletion of one centromere via a RAD52-dependent recombination pathway. We report that dicentric chromosome resolution requires RAD1, a gene involved in the single-strand annealing DNA repair pathway. We additionally show that single-strand annealing repair of a dicentric chromosome can occur in the absence of RAD52. RAD52-independent repair requires the adaptation-defective cdc5-ad allele of the yeast polo kinase and the DNA damage checkpoint gene RAD9. Dicentric chromosome breakage in cdc5-ad rad52 mutant cells is associated with a prolonged mitotic arrest, during which nuclei undergo microtubule-dependent oscillations, accompanied by dynamic changes in nuclear morphology. We further demonstrate that the frequency of spontaneous direct repeat recombination is suppressed in yeast cells treated with benomyl, a drug that perturbs microtubules. Our findings indicate that microtubule-dependent processes facilitate recombination.

  13. Mgm101 is a Rad52-related protein required for mitochondrial DNA recombination.

    PubMed

    Mbantenkhu, MacMillan; Wang, Xiaowen; Nardozzi, Jonathan D; Wilkens, Stephan; Hoffman, Elizabeth; Patel, Anamika; Cosgrove, Michael S; Chen, Xin Jie

    2011-12-09

    Homologous recombination is a conserved molecular process that has primarily evolved for the repair of double-stranded DNA breaks and stalled replication forks. However, the recombination machinery in mitochondria is poorly understood. Here, we show that the yeast mitochondrial nucleoid protein, Mgm101, is related to the Rad52-type recombination proteins that are widespread in organisms from bacteriophage to humans. Mgm101 is required for repeat-mediated recombination and suppression of mtDNA fragmentation in vivo. It preferentially binds to single-stranded DNA and catalyzes the annealing of ssDNA precomplexed with the mitochondrial ssDNA-binding protein, Rim1. Transmission electron microscopy showed that Mgm101 forms large oligomeric rings of ∼14-fold symmetry and highly compressed helical filaments. Specific mutations affecting ring formation reduce protein stability in vitro. The data suggest that the ring structure may provide a scaffold for stabilization of Mgm101 by preventing the aggregation of the otherwise unstable monomeric conformation. Upon binding to ssDNA, Mgm101 is remobilized from the rings to form distinct nucleoprotein filaments. These studies reveal a recombination protein of likely bacteriophage origin in mitochondria and support the notion that recombination is indispensable for mtDNA integrity.

  14. Conformational adaptability of Redbeta during DNA annealing and implications for its structural relationship with Rad52.

    PubMed

    Erler, Axel; Wegmann, Susanne; Elie-Caille, Celine; Bradshaw, Charles Richard; Maresca, Marcello; Seidel, Ralf; Habermann, Bianca; Muller, Daniel J; Stewart, A Francis

    2009-08-21

    Single-strand annealing proteins, such as Redbeta from lambda phage or eukaryotic Rad52, play roles in homologous recombination. Here, we use atomic force microscopy to examine Redbeta quaternary structure and Redbeta-DNA complexes. In the absence of DNA, Redbeta forms a shallow right-handed helix. The presence of single-stranded DNA (ssDNA) disrupts this structure. Upon addition of a second complementary ssDNA, annealing generates a left-handed helix that incorporates 14 Redbeta monomers per helical turn, with each Redbeta monomer annealing approximately 11 bp of DNA. The smallest stable annealing intermediate requires 20 bp DNA and two Redbeta monomers. Hence, we propose that Redbeta promotes base pairing by first increasing the number of transient interactions between ssDNAs. Then, annealing is promoted by the binding of a second Redbeta monomer, which nucleates the formation of a stable annealing intermediate. Using threading, we identify sequence similarities between the RecT/Redbeta and the Rad52 families, which strengthens previous suggestions, based on similarities of their quaternary structures, that they share a common mode of action. Hence, our findings have implications for a common mechanism of DNA annealing mediated by single-strand annealing proteins including Rad52.

  15. A requirement for recombinational repair in Saccharomyces cerevisiae is caused by DNA replication defects of mec1 mutants.

    PubMed Central

    Merrill, B J; Holm, C

    1999-01-01

    To examine the role of the RAD52 recombinational repair pathway in compensating for DNA replication defects in Saccharomyces cerevisiae, we performed a genetic screen to identify mutants that require Rad52p for viability. We isolated 10 mec1 mutations that display synthetic lethality with rad52. These mutations (designated mec1-srf for synthetic lethality with rad-fifty-two) simultaneously cause two types of phenotypes: defects in the checkpoint function of Mec1p and defects in the essential function of Mec1p. Velocity sedimentation in alkaline sucrose gradients revealed that mec1-srf mutants accumulate small single-stranded DNA synthesis intermediates, suggesting that Mec1p is required for the normal progression of DNA synthesis. sml1 suppressor mutations suppress both the accumulation of DNA synthesis intermediates and the requirement for Rad52p in mec1-srf mutants, but they do not suppress the checkpoint defect in mec1-srf mutants. Thus, it appears to be the DNA replication defects in mec1-srf mutants that cause the requirement for Rad52p. By using hydroxyurea to introduce similar DNA replication defects, we found that single-stranded DNA breaks frequently lead to double-stranded DNA breaks that are not rapidly repaired in rad52 mutants. Taken together, these data suggest that the RAD52 recombinational repair pathway is required to prevent or repair double-stranded DNA breaks caused by defective DNA replication in mec1-srf mutants. PMID:10511542

  16. Corrupting the DNA damage response: a critical role for Rad52 in tumor cell survival.

    PubMed

    Lieberman, Rachel; You, Ming

    2017-07-15

    The DNA damage response enables cells to survive, maintain genome integrity, and to safeguard the transmission of high-fidelity genetic information. Upon sensing DNA damage, cells respond by activating this multi-faceted DNA damage response leading to restoration of the cell, senescence, programmed cell death, or genomic instability if the cell survives without proper repair. However, unlike normal cells, cancer cells maintain a marked level of genomic instability. Because of this enhanced propensity to accumulate DNA damage, tumor cells rely on homologous recombination repair as a means of protection from the lethal effect of both spontaneous and therapy-induced double-strand breaks (DSBs) in DNA. Thus, modulation of DNA repair pathways have important consequences for genomic instability within tumor cell biology and viability maintenance under high genotoxic stress. Efforts are underway to manipulate specific components of the DNA damage response in order to selectively induce tumor cell death by augmenting genomic instability past a viable threshold. New evidence suggests that RAD52, a component of the homologous recombination pathway, is important for the maintenance of tumor genome integrity. This review highlights recent reports indicating that reducing homologous recombination through inhibition of RAD52 may represent an important focus for cancer therapy and the specific efforts that are already demonstrating potential.

  17. Nuclear localization of Rad52 is pre-requisite for its sumoylation

    SciTech Connect

    Ohuchi, Takashi; Seki, Masayuki Enomoto, Takemi

    2008-07-18

    In Saccharomyces cerevisiae, Rad52 plays major roles in several types of homologous recombination. Here, we found that rad52-K200R mutation greatly reduced sumoylation of Rad52. The rad52-K200R mutant exhibited defects in various types of recombination, such as intrachromosomal recombination and mating-type switching. The K200 residue of Rad52 is part of the nuclear localization signal (NLS), which is important for transport into the nucleus. Indeed, the addition of a SV40 NLS to Rad52-K200R suppressed the sumoylation defect of Rad52-K200R. These findings indicate that nuclear localization of Rad52 is pre-requisite for its sumoylation.

  18. RAD52 inactivation is synthetically lethal with deficiencies in BRCA1 and PALB2 in addition to BRCA2 through RAD51-mediated homologous recombination.

    PubMed

    Lok, B H; Carley, A C; Tchang, B; Powell, S N

    2013-07-25

    Synthetic lethality is an approach to study selective cell killing based on genotype. Previous work in our laboratory has shown that loss of RAD52 is synthetically lethal with BRCA2 deficiency, while exhibiting no impact on cell growth and viability in BRCA2-proficient cells. We now show that this same synthetically lethal relationship is evident in cells with deficiencies in BRCA1 or PALB2, which implicates BRCA1, PALB2 and BRCA2 in an epistatic relationship with one another. When RAD52 was depleted in BRCA1- or PALB2-deficient cells, a severe reduction in plating efficiency was observed, with many abortive attempts at cell division apparent in the double-depleted background. In contrast, when RAD52 was depleted in a BRCA1- or PALB2-wildtype background, a negligible decrease in colony survival was observed. The frequency of ionizing radiation-induced RAD51 foci formation and double-strand break-induced homologous recombination (HR) was decreased by 3- and 10-fold, respectively, when RAD52 was knocked down in BRCA1- or PALB2-depleted cells, with minimal effect in BRCA1- or PALB2-proficient cells. RAD52 function was independent of BRCA1 status, as evidenced by the lack of any defect in RAD52 foci formation in BRCA1-depleted cells. Collectively, these findings suggest that RAD52 is an alternative repair pathway of RAD51-mediated HR, and a target for therapy in cells deficient in the BRCA1-PALB2-BRCA2 repair pathway.

  19. Modulation of Saccharomyces Cerevisiae DNA Double-Strand Break Repair by Srs2 and Rad51

    PubMed Central

    Milne, G. T.; Ho, T.; Weaver, D. T.

    1995-01-01

    RAD52 function is required for virtually all DNA double-strand break repair and recombination events in Saccharomyces cerevisiae. To gain greater insight into the mechanism of RAD52-mediated repair, we screened for genes that suppress partially active alleles of RAD52 when mutant or overexpressed. Described here is the isolation of a phenotypic null allele of SRS2 that suppressed multiple alleles of RAD52 (rad52B, rad52D, rad52-1 and KlRAD52) and RAD51 (KlRAD51) but failed to suppress either a rad52δ or a rad51δ. These results indicate that SRS2 antagonizes RAD51 and RAD52 function in recombinational repair. The mechanism of suppression of RAD52 alleles by srs2 is distinct from that which has been previously described for RAD51 overexpression, as both conditions were shown to act additively with respect to the rad52B allele. Furthermore, overexpression of either RAD52 or RAD51 enhanced the recombination-dependent sensitivity of an srs2δ RAD52 strain, suggesting that RAD52 and RAD51 positively influence recombinational repair mechanisms. Thus, RAD52-dependent recombinational repair is controlled both negatively and positively. PMID:7768432

  20. 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.

  1. Detection of novel recombinases in bacteriophage genomes unveils Rad52, Rad51 and Gp2.5 remote homologs

    PubMed Central

    Lopes, Anne; Amarir-Bouhram, Jihane; Faure, Guilhem; Petit, Marie-Agnès; Guerois, Raphaël

    2010-01-01

    Homologous recombination is a key in contributing to bacteriophages genome repair, circularization and replication. No less than six kinds of recombinase genes have been reported so far in bacteriophage genomes, two (UvsX and Gp2.5) from virulent, and four (Sak, Redβ, Erf and Sak4) from temperate phages. Using profile–profile comparisons, structure-based modelling and gene-context analyses, we provide new views on the global landscape of recombinases in 465 bacteriophages. We show that Sak, Redβ and Erf belong to a common large superfamily adopting a shortcut Rad52-like fold. Remote homologs of Sak4 are predicted to adopt a shortcut Rad51/RecA fold and are discovered widespread among phage genomes. Unexpectedly, within temperate phages, gene-context analyses also pinpointed the presence of distant Gp2.5 homologs, believed to be restricted to virulent phages. All in all, three major superfamilies of phage recombinases emerged either related to Rad52-like, Rad51-like or Gp2.5-like proteins. For two newly detected recombinases belonging to the Sak4 and Gp2.5 families, we provide experimental evidence of their recombination activity in vivo. Temperate versus virulent lifestyle together with the importance of genome mosaicism is discussed in the light of these novel recombinases. Screening for these recombinases in genomes can be performed at http://biodev.extra.cea.fr/virfam. PMID:20194117

  2. Single cell wound repair

    PubMed Central

    Abreu-Blanco, Maria Teresa; Verboon, Jeffrey M

    2011-01-01

    Cell wounding is a common event in the life of many cell types, and the capacity of the cell to repair day-to-day wear-and-tear injuries, as well as traumatic ones, is fundamental for maintaining tissue integrity. Cell wounding is most frequent in tissues exposed to high levels of stress. Survival of such plasma membrane disruptions requires rapid resealing to prevent the loss of cytosolic components, to block Ca2+ influx and to avoid cell death. In addition to patching the torn membrane, plasma membrane and cortical cytoskeleton remodeling are required to restore cell function. Although a general understanding of the cell wound repair process is in place, the underlying mechanisms of each step of this response are not yet known. We have developed a model to study single cell wound repair using the early Drosophila embryo. Our system combines genetics and live imaging tools, allowing us to dissect in vivo the dynamics of the single cell wound response. We have shown that cell wound repair in Drosophila requires the coordinated activities of plasma membrane and cytoskeleton components. Furthermore, we identified an unexpected role for E-cadherin as a link between the contractile actomyosin ring and the newly formed plasma membrane plug. PMID:21922041

  3. Genetic requirements for the single-strand annealing pathway of double-strand break repair in Saccharomyces cerevisiae

    SciTech Connect

    Ivanov, E.L.; Sugawara, N.; Haber, J.E.

    1996-03-01

    HO endonuclease-induced double-strand breaks (DSBs) within a direct duplication of Escherichia coli lacZ genes are repaired either by gene conversion or by single-strand annealing (SSA), with >80% being SSA. Previously it was demonstrated that the RAD52 gene is required for DSB-induced SSA. In the present study, the effects of other genes belonging to the RAD52 epistasis group were analyzed. We show that RAD51, RAD54, RAD55, and RAD57 genes are not required for SSA irrespective of whether recombination occurred in plasmid or chromosomal DNA. In both plasmid and chromosomal constructs with homologous sequences in direct orientation, the proportion of SSA events over gene conversion was significantly elevated in the mutant strains. However, gene conversion was not affected when the two lacZ sequences were in inverted orientation. These results suggest that there is a competition between SSA and gene conversion processes that favors SSA in the absence of RAD51, RAD54, RAD55 and RAD57. Mutations in RAD50 and XRS2 genes do not prevent the completion, but markedly retard the kinetics, of DSB repair by both mechanisms in the lacZ direct repeat plasmid, a result resembling the effects of these genes during mating-type (MAT) switching. 43 refs., 8 figs., 3 tabs.

  4. Genetic Requirements for the Single-Strand Annealing Pathway of Double-Strand Break Repair in Saccharomyces Cerevisiae

    PubMed Central

    Ivanov, E. L.; Sugawara, N.; Fishman-Lobell, J.; Haber, J. E.

    1996-01-01

    HO endonuclease-induced double-strand breaks (DSBs) within a direct duplication of Escherichia coli lacZ genes are repaired either by gene conversion or by single-strand annealing (SSA), with >80% being SSA. Previously it was demonstrated that the RAD52 gene is required for DSB-induced SSA. In the present study, the effects of other genes belonging to the RAD52 epistasis group were analyzed. We show that RAD51, RAD54, RAD55, and RAD57 genes are not required for SSA irrespective of whether recombination occurred in plasmid or chromosomal DNA. In both plasmid and chromosomal constructs with homologous sequences in direct orientation, the proportion of SSA events over gene conversion was significantly elevated in the mutant strains. However, gene conversion was not affected when the two lacZ sequences were in inverted orientation. These results suggest that there is a competition between SSA and gene conversion processes that favors SSA in the absence of RAD51, RAD54, RAD55 and RAD57. Mutations in RAD50 and XRS2 genes do not prevent the completion, but markedly retard the kinetics, of DSB repair by both mechanisms in the lacZ direct repeat plasmid, a result resembling the effects of these genes during mating-type (MAT) switching. PMID:8849880

  5. Rad51 and Rad52 are involved in homologous recombination of replicating herpes simplex virus DNA.

    PubMed

    Tang, Ka-Wei; Norberg, Peter; Holmudden, Martin; Elias, Per; Liljeqvist, Jan-Åke

    2014-01-01

    Replication of herpes simplex virus 1 is coupled to recombination, but the molecular mechanisms underlying this process are poorly characterized. The role of Rad51 and Rad52 recombinases in viral recombination was examined in human fibroblast cells 1BR.3.N (wild type) and in GM16097 with replication defects caused by mutations in DNA ligase I. Intermolecular recombination between viruses, tsS and tsK, harboring genetic markers gave rise to ∼17% recombinants in both cell lines. Knock-down of Rad51 and Rad52 by siRNA reduced production of recombinants to 11% and 5%, respectively, in wild type cells and to 3% and 5%, respectively, in GM16097 cells. The results indicate a specific role for Rad51 and Rad52 in recombination of replicating herpes simplex virus 1 DNA. Mixed infections using clinical isolates with restriction enzyme polymorphisms in the US4 and US7 genes revealed recombination frequencies of 0.7%/kbp in wild type cells and 4%/kbp in GM16097 cells. Finally, tandem repeats in the US7 gene remained stable upon serial passage, indicating a high fidelity of recombination in infected cells.

  6. Rad51 and Rad52 Are Involved in Homologous Recombination of Replicating Herpes Simplex Virus DNA

    PubMed Central

    Tang, Ka-Wei; Norberg, Peter; Holmudden, Martin; Elias, Per; Liljeqvist, Jan-Åke

    2014-01-01

    Replication of herpes simplex virus 1 is coupled to recombination, but the molecular mechanisms underlying this process are poorly characterized. The role of Rad51 and Rad52 recombinases in viral recombination was examined in human fibroblast cells 1BR.3.N (wild type) and in GM16097 with replication defects caused by mutations in DNA ligase I. Intermolecular recombination between viruses, tsS and tsK, harboring genetic markers gave rise to ∼17% recombinants in both cell lines. Knock-down of Rad51 and Rad52 by siRNA reduced production of recombinants to 11% and 5%, respectively, in wild type cells and to 3% and 5%, respectively, in GM16097 cells. The results indicate a specific role for Rad51 and Rad52 in recombination of replicating herpes simplex virus 1 DNA. Mixed infections using clinical isolates with restriction enzyme polymorphisms in the US4 and US7 genes revealed recombination frequencies of 0.7%/kbp in wild type cells and 4%/kbp in GM16097 cells. Finally, tandem repeats in the US7 gene remained stable upon serial passage, indicating a high fidelity of recombination in infected cells. PMID:25365323

  7. Induction of Ty Recombination in Yeast by Cdna and Transcription: Role of the Rad1 and Rad52 Genes

    PubMed Central

    Nevo-Caspi, Y.; Kupiec, M.

    1996-01-01

    In the yeast Saccharomyces cerevisiae ectopic recombination has been shown to occur at high frequencies for artificially created repeats, but at relatively low frequencies for a natural family of repeated sequences, the Ty family. Little is known about the mechanism(s) that prevent recombination between repeated sequences. We have previously shown that nonreciprocal recombination (gene conversion) of a genetically marked Ty can be induced either by the presence of high levels of Ty cDNA or by transcription of the marked Ty from a GAL1 promoter. These two kinds of induction act in a synergistic manner. To further characterize these two kinds of Ty recombination, we have investigated the role played by the RAD52 and RAD1 genes. We have found that the RAD52 and RAD1 gene products are essential to carry out transcription-induced Ty conversion whereas cDNA-mediated conversion can take place in their absence. PMID:8913740

  8. 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

  9. Temperate phages acquire DNA from defective prophages by relaxed homologous recombination: the role of Rad52-like recombinases.

    PubMed

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

    2014-03-01

    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

  10. 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.

  11. 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

  12. 53BP1 fosters fidelity of homology-directed DNA repair.

    PubMed

    Ochs, Fena; Somyajit, Kumar; Altmeyer, Matthias; Rask, Maj-Britt; Lukas, Jiri; Lukas, Claudia

    2016-08-01

    Repair of DNA double-strand breaks (DSBs) in mammals is coordinated by the ubiquitin-dependent accumulation of 53BP1 at DSB-flanking chromatin. Owing to its ability to limit DNA-end processing, 53BP1 is thought to promote nonhomologous end-joining (NHEJ) and to suppress homology-directed repair (HDR). Here, we show that silencing 53BP1 or exhausting its capacity to bind damaged chromatin changes limited DSB resection to hyper-resection and results in a switch from error-free gene conversion by RAD51 to mutagenic single-strand annealing by RAD52. Thus, rather than suppressing HDR, 53BP1 fosters its fidelity. These findings illuminate causes and consequences of synthetic viability acquired through 53BP1 silencing in cells lacking the BRCA1 tumor suppressor. We show that such cells survive DSB assaults at the cost of increasing reliance on RAD52-mediated HDR, which may fuel genome instability. However, our findings suggest that when challenged by DSBs, BRCA1- and 53BP1-deficient cells may become hypersensitive to, and be eliminated by, RAD52 inhibition.

  13. Inherited variation at chromosome 12p13.33 including RAD52 influences squamous cell lung carcinoma risk

    PubMed Central

    Shi, Jianxin; Chatterjee, Nilanjan; Rotunno, Melissa; Wang, Yufei; Pesatori, Angela C.; Consonni, Dario; Li, Peng; Wheeler, William; Broderick, Peter; Henrion, Marc; Eisen, Timothy; Wang, Zhaoming; Chen, Wei; Dong, Qiong; Albanes, Demetrius; Thun, Michael; Spitz, Margaret R.; Bertazzi, Pier Alberto; Caporaso, Neil E.; Chanock, Stephen J.; Amos, Christopher I.; Houlston, Richard S.; Landi, Maria Teresa

    2011-01-01

    While lung cancer is largely caused by tobacco smoking, inherited genetic factors play a role in its etiology. Genome-wide association studies (GWAS) in Europeans have robustly demonstrated only three polymorphic variations influencing lung cancer risk. Tumor heterogeneity may have hampered the detection of association signal when all lung cancer subtypes were analyzed together. In a GWAS of 5,355 European smoking lung cancer cases and 4,344 smoking controls, we conducted a pathway-based analysis in lung cancer histologic subtypes with 19,082 SNPs mapping to 917 genes in the HuGE-defined “inflammation” pathway. We identified a susceptibility locus for squamous cell lung carcinoma (SQ) at 12p13.33 (RAD52, rs6489769), and replicated the association in three independent samples totaling 3,359 SQ cases and 9,100 controls (odds ratio=1.20, Pcombined=2.3×10−8). Significance The combination of pathway-based approaches and information on disease specific subtypes can improve the identification of cancer susceptibility loci in heterogeneous diseases. PMID:22585858

  14. Single pass, single suture technique for repair of traumatic mydriasis.

    PubMed

    Angmo, Dewang; Agarwal, Tushar; Khokhar, Sudarshan

    2013-01-01

    We describe a 52-year-old man with pseudophakia and traumatic mydriasis who presented with severe glare. A modification of the Siepser sliding knot technique-single pass, single suture technique-allows the surgeon to create a locking knot at the extraocular space while maintaining a closed chamber, a safer and easier method for traumatic mydriasis repair. A reduction of pupil size from 8.0×7.8 mm to 5.5 mm was noted. The patient's complaint of glare was relieved and the glare acuity was 20/40 at 6 months follow-up. We present a new, simpler application of the Siepser slipknot which can be used successfully for repair of traumatic mydriasis.

  15. 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

  16. Cisplatin-modification of DNA repair and ionizing radiation lethality in yeast, Saccharomyces cerevisiae.

    PubMed

    Dolling, J A; Boreham, D R; Brown, D L; Raaphorst, G P; Mitchel, R E

    1999-03-10

    Cis-diamminedichloroplatinum II (cisplatin) is a DNA inter- and intrastrand crosslinking agent which can sensitize prokaryotic and eukaryotic cells to killing by ionizing radiation. The mechanism of radiosensitization is unknown but may involve cisplatin inhibition of repair of DNA damage caused by radiation. Repair proficient wild type and repair deficient (rad52, recombinational repair or rad3, excision repair) strains of the yeast Saccharomyces cerevisiae were used to determine whether defects in DNA repair mechanisms would modify the radiosensitizing effect of cisplatin. We report that cisplatin exposure could sensitize yeast cells with a competent recombinational repair mechanism (wild type or rad3), but could not sensitize cells defective in recombinational repair (rad52), indicating that the radiosensitizing effect of cisplatin was due to inhibition of DNA repair processes involving error free RAD52-dependent recombinational repair. The presence or absence of oxygen during irradiation did not alter this radiosensitization. Consistent with this result, cisplatin did not sensitize cells to mutation that results from lesion processing by an error prone DNA repair system. However, under certain circumstances, cisplatin exposure did not cause radiosensitization to killing by radiation in repair competent wild type cells. Within 2 h after a sublethal cisplatin treatment, wild type yeast cells became both thermally tolerant and radiation resistant. Cisplatin pretreatment also suppressed mutations caused by exposure to N-methyl-N'-nitro-N-nitrosoguanidine (MNNG), a response previously shown in wild type yeast cells following radiation pretreatment. Like radiation, the cisplatin-induced stress response did not confer radiation resistance or suppress MNNG mutations in a recombinational repair deficient mutant (rad52), although thermal tolerance was still induced. These results support the idea that cisplatin adducts in DNA interfere with RAD52-dependent

  17. Studying the organization of DNA repair by single-cell and single-molecule imaging

    PubMed Central

    Uphoff, Stephan; Kapanidis, Achillefs N.

    2014-01-01

    DNA repair safeguards the genome against a diversity of DNA damaging agents. Although the mechanisms of many repair proteins have been examined separately in vitro, far less is known about the coordinated function of the whole repair machinery in vivo. Furthermore, single-cell studies indicate that DNA damage responses generate substantial variation in repair activities across cells. This review focuses on fluorescence imaging methods that offer a quantitative description of DNA repair in single cells by measuring protein concentrations, diffusion characteristics, localizations, interactions, and enzymatic rates. Emerging single-molecule and super-resolution microscopy methods now permit direct visualization of individual proteins and DNA repair events in vivo. We expect much can be learned about the organization of DNA repair by linking cell heterogeneity to mechanistic observations at the molecular level. PMID:24629485

  18. Single molecule techniques in DNA repair: A primer

    PubMed Central

    Hughes, Craig D.; Simons, Michelle; Mackenzie, Cassidy E.; Van Houten, Bennett; Kad, Neil M.

    2016-01-01

    A powerful new approach has become much more widespread and offers insights into aspects of DNA repair unattainable with billions of molecules. Single molecule techniques can be used to image, manipulate or characterize the action of a single repair protein on a single strand of DNA. This allows search mechanisms to be probed, and the effects of force to be understood. These physical aspects can dominate a biochemical reaction, where at the ensemble level their nuances are obscured. In this paper we discuss some of the many technical advances that permit study at the single molecule level. We focus on DNA repair to which these techniques are actively being applied. DNA repair is also a process that encompasses so much of what single molecule studies benefit – searching for targets, complex formation, sequential biochemical reactions and substrate hand-off to name just a few. We discuss how single molecule biophysics is poised to transform our understanding of biological systems, in particular DNA repair. PMID:24819596

  19. Ectopia cordis, a successful single stage thoracoabdominal repair.

    PubMed

    Samir, Khaled; Ghez, Olivier; Metras, Dominique; Kreitmann, Bernard

    2003-12-01

    This is a report of a case of the rare ectopia cordis malformation of the thoracoabdominal type without intracardiac anomalies. The patient had a successful single stage repair with reduction of the herniating heart and reconstruction of a cartilaginous cover to protect the heart. The result was very good and the follow up for 13 months was very satisfactory.

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

    ERIC Educational Resources Information Center

    Whitehill, Tara; Chau, Cynthia

    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. Homologous recombination rescues ssDNA gaps generated by nucleotide excision repair and reduced translesion DNA synthesis in yeast G2 cells

    PubMed Central

    Ma, Wenjian; Westmoreland, James W.; Resnick, Michael A.

    2013-01-01

    Repair of DNA bulky lesions often involves multiple repair pathways such as nucleotide-excision repair, translesion DNA synthesis (TLS), and homologous recombination (HR). Although there is considerable information about individual pathways, little is known about the complex interactions or extent to which damage in single strands, such as the damage generated by UV, can result in double-strand breaks (DSBs) and/or generate HR. We investigated the consequences of UV-induced lesions in nonreplicating G2 cells of budding yeast. In contrast to WT cells, there was a dramatic increase in ssDNA gaps for cells deficient in the TLS polymerases η (Rad30) and ζ (Rev3). Surprisingly, repair in TLS-deficient G2 cells required HR repair genes RAD51 and RAD52, directly revealing a redundancy of TLS and HR functions in repair of ssDNAs. Using a physical assay that detects recombination between circular sister chromatids within a few hours after UV, we show an approximate three-fold increase in recombinants in the TLS mutants over that in WT cells. The recombination, which required RAD51 and RAD52, does not appear to be caused by DSBs, because a dose of ionizing radiation producing 20 times more DSBs was much less efficient than UV in producing recombinants. Thus, in addition to revealing TLS and HR functional redundancy, we establish that UV-induced recombination in TLS mutants is not attributable to DSBs. These findings suggest that ssDNA that might originate during the repair of closely opposed lesions or of ssDNA-containing lesions or from uncoupled replication may drive recombination directly in various species, including humans. PMID:23858457

  2. Single-row repair versus double-row repair of full-thickness rotator cuff tears.

    PubMed

    Prasathaporn, Niti; Kuptniratsaikul, Somsak; Kongrukgreatiyos, Kitiphong

    2011-07-01

    The purpose of this meta-analysis was to assess whether there are differences in the outcomes between single-row and double-row rotator cuff repair. Using MEDLINE, SCOPUS, SCIRUS, CINAHL, and the Cochrane Library, as well as a hand search, we searched for articles comparing single-row and double-row rotator cuff repair that were published before September 2009. The controlled clinical studies that met the inclusion and exclusion criteria were assessed for quality of methodology. Two of the authors performed this review and assessment. Any disagreements were resolved by the third author. Three randomized controlled studies and two controlled clinical cohort studies were included in this meta-analysis. These studies were assessed as having a moderate to high level of evidence. The results showed that double-row repair improved tendon healing and provided greater external rotation but with significantly increased operative time. Furthermore, this study found that double-row repair decreased the recurrence rate. However, there were no statistically significant differences found in shoulder function as assessed by Constant score; American Shoulder and Elbow Surgeons (ASES) score; University of California, Los Angeles (UCLA) score; Western Ontario Rotator Cuff (WORC) index; Disabilities of the Arm, Shoulder and Hand (DASH) score; muscle strength; forward flexion; internal rotation; patient satisfaction; return to work; and adverse events. Despite the fact that double-row repair shows a significantly higher rate of tendon healing and greater external rotation than does single-row repair, there is no significant improvement in shoulder function, muscle strength, forward flexion, internal rotation, patient satisfaction, or return to work. Level II, meta-analysis of Level I and Level II studies. Copyright © 2011 Arthroscopy Association of North America. All rights reserved.

  3. Microfluidic guillotine for single-cell wound repair studies

    NASA Astrophysics Data System (ADS)

    Blauch, Lucas R.; Gai, Ya; Khor, Jian Wei; Sood, Pranidhi; Marshall, Wallace F.; Tang, Sindy K. Y.

    2017-07-01

    Wound repair is a key feature distinguishing living from nonliving matter. Single cells are increasingly recognized to be capable of healing wounds. The lack of reproducible, high-throughput wounding methods has hindered single-cell wound repair studies. This work describes a microfluidic guillotine for bisecting single Stentor coeruleus cells in a continuous-flow manner. Stentor is used as a model due to its robust repair capacity and the ability to perform gene knockdown in a high-throughput manner. Local cutting dynamics reveals two regimes under which cells are bisected, one at low viscous stress where cells are cut with small membrane ruptures and high viability and one at high viscous stress where cells are cut with extended membrane ruptures and decreased viability. A cutting throughput up to 64 cells per minute—more than 200 times faster than current methods—is achieved. The method allows the generation of more than 100 cells in a synchronized stage of their repair process. This capacity, combined with high-throughput gene knockdown in Stentor, enables time-course mechanistic studies impossible with current wounding methods.

  4. Single-Incision Laparoscopic Ventral Hernia Repair with Suprapubic Incision

    PubMed Central

    Turingan, Isidro; Tran, Mai

    2013-01-01

    Introduction: Although natural orifice transluminal endoscopic surgery promises truly scarless surgery, this has not progressed beyond the experimental setting and a few clinical cases in the field of ventral hernia repair. This is mainly because of the problem of sterilizing natural orifices, which prevents the use of any prosthetic material because of unacceptable risks of infection. Single-incision laparoscopic ventral hernia repair has gained more widespread acceptance by specialized hernia centers. Even so, there is a special subset of patients who are young and/or scar conscious and find any visible scar unacceptable. This study illustrates an innovative way of performing single-incision laparoscopic ventral hernia repair by a transverse suprapubic incision below the pubic hair/bikini line in 2 young male patients who had both umbilical and epigastric hernias as well as attenuated linea alba in the upper abdomen. Case Description: Both patients underwent successful laparoscopic repair, and both were highly satisfied with the procedure, which produced no visible scars on their abdomen. Discussion: Willingness to adopt new innovative procedures, such as single-incision laparoscopic surgery, has allowed modification of the incision site to produce invisible scars and hence become highly attractive to the young and scar-phobic segment of the population. PMID:23925028

  5. Single-incision laparoscopic repair of Spigelian hernia.

    PubMed

    Tran, Hanh; Tran, Kim; Zajkowska, Marta; Lam, Vincent; Hawthorne, Wayne J

    2015-01-01

    Spigelian hernias represent only 1% to 2% of all abdominal wall hernias. The treatment, however, remains controversial but depends on institutional expertise. This case series reports the first experience with single-incision laparoscopic totally extraperitoneal (SILTEP) repair of Spigelian hernias with telescopic extraperitoneal dissection in combination with inguinal hernia repair. From February 2013 to April 2014, all patients referred with inguinal or Spigelian hernias, without histories of extraperitoneal intervention, underwent SILTEP repair with telescopic extraperitoneal dissection. A single-port device, 5.5 mm/52 cm/30° angled laparoscope, and conventional straight dissecting instruments were used for all cases. Extraperitoneal dissection was performed under direct vision with preservation of preperitoneal fascia overlying retroperitoneal nerves. Inguinal herniorrhaphy was performed with lightweight mesh that covered low-lying Spigelian defects. High-lying Spigelian defects were repaired with additional mesh. There were 131 patients with 186 (92 direct) inguinal hernias and 7 patients with 8 Spigelian hernias (6 incidental, including 1 bilateral and 2 preoperatively diagnosed), with a mean age of 51.3 years and a mean body mass index of 25.1 kg/m(2). An additional piece of mesh was used for 3 hernias. All Spigelian hernias were associated with direct inguinal hernias, and 8 combined inguinal and Spigelian hernias were successfully repaired with SILTEP repair with telescopic extraperitoneal dissection as day cases. There were no clinical recurrences during a mean follow-up period of 6 months (range, 1-15 months). Combined Spigelian and inguinal hernias can be successfully treated with SILTEP herniorrhaphy with telescopic extraperitoneal dissection. The high incidence of Spigelian hernias associated with direct inguinal hernias suggests a high index of suspicion for Spigelian hernias during laparoscopic inguinal herniorrhaphy.

  6. Single-Incision Laparoscopic Repair of Spigelian Hernia

    PubMed Central

    Tran, Kim; Zajkowska, Marta; Lam, Vincent; Hawthorne, Wayne J.

    2015-01-01

    Introduction: Spigelian hernias represent only 1% to 2% of all abdominal wall hernias. The treatment, however, remains controversial but depends on institutional expertise. This case series reports the first experience with single-incision laparoscopic totally extraperitoneal (SILTEP) repair of Spigelian hernias with telescopic extraperitoneal dissection in combination with inguinal hernia repair. Methods: From February 2013 to April 2014, all patients referred with inguinal or Spigelian hernias, without histories of extraperitoneal intervention, underwent SILTEP repair with telescopic extraperitoneal dissection. A single-port device, 5.5 mm/52 cm/30° angled laparoscope, and conventional straight dissecting instruments were used for all cases. Extraperitoneal dissection was performed under direct vision with preservation of preperitoneal fascia overlying retroperitoneal nerves. Inguinal herniorrhaphy was performed with lightweight mesh that covered low-lying Spigelian defects. High-lying Spigelian defects were repaired with additional mesh. Results: There were 131 patients with 186 (92 direct) inguinal hernias and 7 patients with 8 Spigelian hernias (6 incidental, including 1 bilateral and 2 preoperatively diagnosed), with a mean age of 51.3 years and a mean body mass index of 25.1 kg/m2. An additional piece of mesh was used for 3 hernias. All Spigelian hernias were associated with direct inguinal hernias, and 8 combined inguinal and Spigelian hernias were successfully repaired with SILTEP repair with telescopic extraperitoneal dissection as day cases. There were no clinical recurrences during a mean follow-up period of 6 months (range, 1–15 months). Conclusions: Combined Spigelian and inguinal hernias can be successfully treated with SILTEP herniorrhaphy with telescopic extraperitoneal dissection. The high incidence of Spigelian hernias associated with direct inguinal hernias suggests a high index of suspicion for Spigelian hernias during laparoscopic inguinal

  7. ROBOTIC ASSISTED SINGLE SITE FOR BILATERAL INGUINAL HERNIA REPAIR.

    PubMed

    Bosi, Henrique Rasia; Guimarães, José Ricardo; Cavazzola, Leandro Totti

    2016-01-01

    The inguinal hernia is one of the most frequent surgical diseases, being frequent procedure and surgeon´s everyday practice. To present technical details in making hernioplasty using robotic equipment on bilateral inguinal hernia repair with single port and preliminary results with the method. The bilateral inguinal hernia repair was performed by using the Single-Site(c) Da Vinci Surgical Access Platform to the abdominal cavity and the placement of clamps. This technique proved to be effective for inguinal hernia and have more aesthetic result when compared to other techniques. Inguinal hernia repair robot-assisted with single-trocar is feasible and effective. However, still has higher costs needing surgical team special training. A hérnia inguinal é uma das doenças cirúrgicas mais frequentes, tornando-a procedimento frequente e do cotidiano do cirurgião. Apresentar detalhes da técnica da hernioplastia inguinal bilateral robótica por single-site e resultados preliminares com o método. Foi realizada hernioplastia inguinal bilateral assistida por robô, utilizando-se da Vinci Single-Site(c) Surgical Platform para acesso a cavidade abdominal e colocação das pinças. Esta técnica demonstrou-se efetiva para correção da hérnia inguinal, além de apresentar melhor resultado estético quando comparado às outras técnicas. A hernioplastia inguinal assistida por robô com trocarte único é viável e eficaz. Contudo, ainda apresenta custos mais elevados e necessidade de treinamento especial por parte da equipe cirúrgica.

  8. Single-Port Onlay Mesh Repair of Recurrent Inguinal Hernias after Failed Anterior and Laparoscopic Repairs

    PubMed Central

    Tran, Kim; Zajkowska, Marta; Lam, Vincent; Hawthorne, Wayne J.

    2015-01-01

    Background and Objectives: Despite the exponential increase in the use of laparoscopic inguinal herniorrhaphy, overall recurrence rates have remained unchanged. Therefore, a growing number of patients are presenting with recurrent hernias after conventional anterior and laparoscopic repairs have failed. This study reports our experience with single-incision laparoscopic (SIL) intraperitoneal onlay mesh (IPOM) repair of these hernias. Methods: Patients referred with two or more recurrences of inguinal hernia underwent SIL-IPOM from November 1, 2009, to June 24, 2014. A 2.5-cm infraumbilical incision was made, and an SIL port was placed intraperitoneally. Modified dissection techniques were used: chopstick and inline dissection, 5.5-mm/52-cm/30° angled laparoscope, and conventional straight dissecting instruments. The peritoneum was incised above the pubic symphysis, and dissection was continued laterally and proximally, raising the inferior flap below the previous extraperitoneal mesh while reducing any direct, indirect, femoral, or cord lipoma before placement of antiadhesive mesh, which was fixed to the pubic ramus, as well as superiorly, with nonabsorbable tacks before the inferior border was fixed with fibrin sealant. The inferior peritoneal flap was then tacked back onto the mesh. Results: Nine male patients underwent SIL-IPOM. Their mean age was 53 years and mean body mass index was 26.8 kg/m2. Mean mesh size was 275 cm2. Mean operation time was 125 minutes, with a hospital stay of 1 day. The umbilical scar length was 23 mm at the 6-week follow-up. There were no intra-/postoperative complications, port-site hernias, chronic groin pain, or recurrence of the hernia during a mean follow-up of 24 months. Conclusion: Inguinal hernias recurring after two or more failed conventional anterior and laparoscopic repairs can be safely and efficiently treated with SIL-IPOM. PMID:25848186

  9. Sister chromatid exchange, DNA repair, and single-gene mutation

    SciTech Connect

    Carrano, A.V.; Thompson, L.H.

    1982-01-01

    Sister chromatid exchange (SCE) has been studied in cultured mammalian cells with regard to the nature of the inducing lesion, mutation induction, and factors that modify the observed frequency following mutagen exposure, SCEs can be induced by a wide spectrum of DNA lesions and, for nine agents examined, the frequency of induced SCE is linearly related to induced single-gene mutation. Further, a deficiency in DNA repair may alter the expression of both SCE and mutation in a qualitatively similar manner. The frequency of SCE induced by mitomycin-C is suppressed in heterochromatic relative to euchromatin and, in nondividing lymphocytes, the lesions leading to the formation of SCEs may persist for several months.

  10. Single-nucleotide patch base excision repair of uracil in DNA by mitochondrial protein extracts.

    PubMed

    Stierum, R H; Dianov, G L; Bohr, V A

    1999-09-15

    Mammalian mitochondria contain several 16.5 kb circular DNAs (mtDNA) encoding electron transport chain proteins. Reactive oxygen species formed as byproducts from oxidative phosphorylation in these organelles can cause oxidative deamination of cytosine and lead to uracil in mtDNA. Upon mtDNA replication, these lesions, if unrepaired, can lead to mutations. Until recently, it was thought that there was no DNA repair in mitochondria, but lately there is evidence that some lesions are efficiently repaired in these organelles. In the study of nuclear DNA repair, the in vitro repair measurements in cell extracts have provided major insights into the mechanisms. The use of whole-cell extract based DNA repair methods has revealed that mammalian nuclear base excision repair (BER) diverges into two pathways: the single-nucleotide replacement and long patch repair mechanisms. Similar in vitro methods have not been available for the study of mitochondrial BER. We have established an in vitro DNA repair system supported by rat liver mitochondrial protein extract and DNA substrates containing a single uracil opposite to a guanine. Using this approach, we examined the repair pathways and the identity of the DNA polymerase involved in mitochondrial BER (mtBER). Employing restriction analysis of in vitro repaired DNA to map the repair patch size, we demonstrate that only one nucleotide is incorporated during the repair process. Thus, in contrast to BER in the nucleus, mtBER of uracil in DNA is solely accomplished by single-nucleotide replacement.

  11. SAW1 is required for SDSA double-strand break repair in S. cerevisiae.

    PubMed

    Diamante, Graciel; Phan, Claire; Celis, Angie S; Krueger, Jonas; Kelson, Eric P; Fischhaber, Paula L

    2014-03-14

    SAW1, coding for Saw1, is required for single-strand annealing (SSA) DNA double-strand break (DSB) repair in Saccharomycescerevisiae. Saw1 physically associates with Rad1 and Rad52 and recruits the Rad1-Rad10 endonuclease. Herein we show by fluorescence microscopy that SAW1 is similarly required for recruitment of Rad10 to sites of Synthesis-Dependent Strand Annealing (SDSA) and associates with sites of SDSA repair in a manner temporally overlapped with Rad10. The magnitude of induction of colocalized Saw1-CFP/Rad10-YFP/DSB-RFP foci in SDSA is more dramatic in S and G2 phase cells than in M phase, consistent with the known mechanism of SDSA. We observed a substantial fraction of foci in which Rad10 was localized to the repair site without Saw1, but few DSB sites that contained Saw1 without Rad10. Together these data are consistent with a model in which Saw1 recruits Rad1-Rad10 to SDSA sites, possibly even binding as a protein-protein complex, but departs the repair site in advance of Rad1-Rad10.

  12. Single molecule PCR reveals similar patterns of non-homologous DSB repair in tobacco and Arabidopsis.

    PubMed

    Lloyd, Andrew H; Wang, Dong; Timmis, Jeremy N

    2012-01-01

    DNA double strand breaks (DSBs) occur constantly in eukaryotes. These potentially lethal DNA lesions are repaired efficiently by two major DSB repair pathways: homologous recombination and non-homologous end joining (NHEJ). We investigated NHEJ in Arabidopsis thaliana and tobacco (Nicotiana tabacum) by introducing DNA double-strand breaks through inducible expression of I-SceI, followed by amplification of individual repair junction sequences by single-molecule PCR. Using this process over 300 NHEJ repair junctions were analysed in each species. In contrast to previously published variation in DSB repair between Arabidopsis and tobacco, the two species displayed similar DSB repair profiles in our experiments. The majority of repair events resulted in no loss of sequence and small (1-20 bp) deletions occurred at a minority (25-45%) of repair junctions. Approximately ~1.5% of the observed repair events contained larger deletions (>20 bp) and a similar percentage contained insertions. Strikingly, insertion events in tobacco were associated with large genomic deletions at the site of the DSB that resulted in increased micro-homology at the sequence junctions suggesting the involvement of a non-classical NHEJ repair pathway. The generation of DSBs through inducible expression of I-SceI, in combination with single molecule PCR, provides an effective and efficient method for analysis of individual repair junctions and will prove a useful tool in the analysis of NHEJ.

  13. Unloading of homologous recombination factors is required for restoring double-stranded DNA at damage repair loci.

    PubMed

    Vasianovich, Yulia; Altmannova, Veronika; Kotenko, Oleksii; Newton, Matthew D; Krejci, Lumir; Makovets, Svetlana

    2017-01-17

    Cells use homology-dependent DNA repair to mend chromosome breaks and restore broken replication forks, thereby ensuring genome stability and cell survival. DNA break repair via homology-based mechanisms involves nuclease-dependent DNA end resection, which generates long tracts of single-stranded DNA required for checkpoint activation and loading of homologous recombination proteins Rad52/51/55/57. While recruitment of the homologous recombination machinery is well characterized, it is not known how its presence at repair loci is coordinated with downstream re-synthesis of resected DNA We show that Rad51 inhibits recruitment of proliferating cell nuclear antigen (PCNA), the platform for assembly of the DNA replication machinery, and that unloading of Rad51 by Srs2 helicase is required for efficient PCNA loading and restoration of resected DNA As a result, srs2Δ mutants are deficient in DNA repair correlating with extensive DNA processing, but this defect in srs2Δ mutants can be suppressed by inactivation of the resection nuclease Exo1. We propose a model in which during re-synthesis of resected DNA, the replication machinery must catch up with the preceding processing nucleases, in order to close the single-stranded gap and terminate further resection. © 2016 The Authors. Published under the terms of the CC BY 4.0 license.

  14. Single-stranded oligonucleotide-mediated gene repair in mammalian cells has a mechanism distinct from homologous recombination repair.

    PubMed

    Wang, Zai; Zhou, Zhong-Jun; Liu, De-Pei; Huang, Jian-Dong

    2006-11-24

    Single-stranded DNA oligonucleotide (SSO)-mediated gene repair has great potentials for gene therapy and functional genomic studies. However, its underlying mechanism remains unclear. Previous studies from other groups have suggested that DNA damage response via the ATM/ATR pathway may be involved in this process. In this study, we measured the effect of two ATM/ATR inhibitors caffeine and pentoxifylline on the correction efficiency in SSO-mediated gene repair. We also checked their effect on double-stranded break (DSB)-induced homologous recombination repair (HRR) as a control, which is well known to be dependent on the ATM/ATR pathway. We found these inhibitors could completely inhibit DSB-induced HRR, but could only partially inhibit SSO-mediated process, indicating SSO-mediated gene repair is not dependent on the ATM/ATR pathway. Furthermore, we found that thymidine treatment promotes SSO-mediated gene repair, but inhibits DSB-induced HRR. Collectively, our results demonstrate that SSO-mediated and DSB-induced gene repairs have distinct mechanisms.

  15. Single-stage repair of aortic coarctation and multiple concomitant cardiac lesions through a median sternotomy.

    PubMed

    Kervan, Umit; Yurdakok, Okan; Genc, Bahadir; Ozen, Anil; Saritas, Ahmet; Kucuker, Seref Alp; Pac, Mustafa

    2013-01-01

    Through a median sternotomy, we performed a single-stage repair of severe aortic coarctation, ventricular septal defect, patent foramen ovale, and mitral valve insufficiency. The severe aortic coarctation was repaired by interposing a synthetic graft between the distal ascending aorta and the descending aorta. We first repaired the coarctation with the 38-year-old man on cardiopulmonary bypass, before aortic cross-clamping, in order to shorten the cross-clamp time.

  16. Clinical results of single-session bilateral medial patellar luxation repair in 26 small breed dogs.

    PubMed

    Balogh, Daniel G; Kramek, Betty

    2016-04-01

    Medical records of 26 small breed dogs treated with single-session bilateral medial patellar luxation repair were reviewed. Excluding dogs with complications associated with cranial cruciate ligament disease, 20/21 dogs with long-term follow-up achieved a complete or acceptable clinical recovery. The complication rate was not increased compared to that previously reported for unilateral patellar luxation repair.

  17. MTE1 Functions with MPH1 in Double-Strand Break Repair.

    PubMed

    Yimit, Askar; Kim, TaeHyung; Anand, Ranjith P; Meister, Sarah; Ou, Jiongwen; Haber, James E; Zhang, Zhaolei; Brown, Grant W

    2016-05-01

    Double-strand DNA breaks occur upon exposure of cells to ionizing radiation and certain chemical agents or indirectly through replication fork collapse at DNA damage sites. If left unrepaired, double-strand breaks can cause genome instability and cell death, and their repair can result in loss of heterozygosity. In response to DNA damage, proteins involved in double-strand break repair by homologous recombination relocalize into discrete nuclear foci. We identified 29 proteins that colocalize with recombination repair protein Rad52 in response to DNA damage. Of particular interest, Ygr042w/Mte1, a protein of unknown function, showed robust colocalization with Rad52. Mte1 foci fail to form when the DNA helicase gene MPH1 is absent. Mte1 and Mph1 form a complex and are recruited to double-strand breaks in vivo in a mutually dependent manner. MTE1 is important for resolution of Rad52 foci during double-strand break repair and for suppressing break-induced replication. Together our data indicate that Mte1 functions with Mph1 in double-strand break repair.

  18. Lung cancer and DNA repair genes: multilevel association analysis from the International Lung Cancer Consortium

    PubMed Central

    Kazma, Rémi; Babron, Marie-Claude; Gaborieau, Valérie; Génin, Emmanuelle; Brennan, Paul; Hung, Rayjean J.; McLaughlin, John R.; Krokan, Hans E.; Elvestad, Maiken B.; Skorpen, Frank; Anderssen, Endre; Vooder, Tõnu; Välk, Kristjan; Metspalu, Andres; Field, John K.; Lathrop, Mark; Sarasin, Alain; Benhamou, Simone

    2012-01-01

    Lung cancer (LC) is the leading cause of cancer-related death worldwide and tobacco smoking is the major associated risk factor. DNA repair is an important process, maintaining genome integrity and polymorphisms in DNA repair genes may contribute to susceptibility to LC. To explore the role of DNA repair genes in LC, we conducted a multilevel association study with 1655 single nucleotide polymorphisms (SNPs) in 211 DNA repair genes using 6911 individuals pooled from four genome-wide case–control studies. Single SNP association corroborates previous reports of association with rs3131379, located on the gene MSH5 (P = 3.57 × 10-5) and returns a similar risk estimate. The effect of this SNP is modulated by histological subtype. On the log-additive scale, the odds ratio per allele is 1.04 (0.84–1.30) for adenocarcinomas, 1.52 (1.28–1.80) for squamous cell carcinomas and 1.31 (1.09–1.57) for other histologies (heterogeneity test: P = 9.1 × 10−3). Gene-based association analysis identifies three repair genes associated with LC (P < 0.01): UBE2N, structural maintenance of chromosomes 1L2 and POLB. Two additional genes (RAD52 and POLN) are borderline significant. Pathway-based association analysis identifies five repair pathways associated with LC (P < 0.01): chromatin structure, DNA polymerases, homologous recombination, genes involved in human diseases with sensitivity to DNA-damaging agents and Rad6 pathway and ubiquitination. This first international pooled analysis of a large dataset unravels the role of specific DNA repair pathways in LC and highlights the importance of accounting for gene and pathway effects when studying LC. PMID:22382497

  19. Inhibition of DNA double-strand break repair by the Ku heterodimer in mrx mutants of Saccharomyces cerevisiae

    PubMed Central

    Wasko, Brian M.; Holland, Cory L.; Resnick, Michael A.; Lewis, L. Kevin

    2009-01-01

    Yeast rad50 and mre11 nuclease mutants are hypersensitive to physical and chemical agents that induce DNA double-strand breaks (DSBs). This sensitivity was suppressed by elevating intracellular levels of TLC1, the RNA subunit of telomerase. Suppression required proteins linked to homologous recombination, including Rad51, Rad52, Rad59 and Exo1, but not genes of the nonhomologous end-joining (NHEJ) repair pathway. Deletion mutagenesis experiments demonstrated that the 5′ end of TLC1 RNA was essential and a segment containing a binding site for the Yku70/Yku80 complex was sufficient for suppression. A mutant TLC1 RNA unable to associate with Yku80 protein did not increase resistance. These and other genetic studies indicated that association of the Ku heterodimer with broken DNA ends inhibits recombination in mrx mutants, but not in repair-proficient cells or in other DNA repair single mutants. In support of this model, DNA damage resistance of mrx cells was enhanced when YKU70 was co-inactivated. Defective recombinational repair of DSBs in mrx cells thus arises from at least two separate processes: loss of Mrx nuclease-associated DNA end-processing and inhibition of the Exo1-mediated secondary recombination pathway by Ku. PMID:18992851

  20. Single-Versus Double-Row Arthroscopic Rotator Cuff Repair in Massive Tears

    PubMed Central

    Wang, EnZhi; Wang, Liang; Gao, Peng; Li, ZhongJi; Zhou, Xiao; Wang, SongGang

    2015-01-01

    Background It is a challenge for orthopaedic surgeons to treat massive rotator cuff tears. The optimal management of massive rotator cuff tears remains controversial. Therefore, the goal of this study was to compare arthroscopic single- versus double-row rotator cuff repair with a larger sample size. Material/Methods Of the subjects with massive rotator cuff tears, 146 were treated using single-row repair, and 102 were treated using double-row repair. Pre- and postoperative functional outcomes and radiographic images were collected. The clinical outcomes were evaluated for a minimum of 2 years. Results No significant differences were shown between the groups in terms of functional outcomes. Regarding the integrity of the tendon, a lower rate of post-treatment retear was observed in patients who underwent double-row repair compared with single-row repair. Conclusions The results suggest that double-row repair is relatively superior in shoulder ROM and the strength of tendon compared with single-row repair. Future studies involving more patients in better-designed randomized controlled trials will be required. PMID:26017641

  1. Repair of Single- and Multiple-Substitution Mismatches during Recombination in Streptococcus Pneumoniae

    PubMed Central

    Gasc, A. M.; Sicard, A. M.; Claverys, J. P.

    1989-01-01

    The use as genetic markers, during transformation of Streptococcus pneumoniae, of 19 sequences differing from wild type, located throughout the amiA locus, enabled us to examine the fate of 24 single- and 11 multiple-mismatches during recombination. Tentative mismatch ranking as a function of decreasing repair efficiency by the Hex mismatch repair system is G/T = A/C = G/G (maximum repair: 90-95%) > C/T (mostly 75 to 90% repair) > A/A (from 50 to 90% repair) > T/T (50-65% repair) > A/G (from 0 to 20% repair) > C/C. No indication of correction of the latter has been obtained. Over the limited number of samples examined, we observed no influence of the base composition of the surrounding sequence on correction efficiency for both transition mismatches and for G/G and C/C. Variations in the surrounding sequence affect repair of A/G and C/T, and, even more strongly, of A/A and T/T. No simple correlation to the G:C content of the surrounding sequence is apparent from our results, in contrast to the conclusion drawn for the Mut mismatch repair system of Escherichia coli. Examination of the fate of multiple mismatches suggests that C/C may sometimes impede recognition of otherwise corrected mismatches. PMID:2645195

  2. 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.

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

    DOE PAGES

    Janssen, Aniek; Breuer, Gregory A.; Brinkman, Eva K.; ...

    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,more » 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.« less

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

    SciTech Connect

    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.

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

    PubMed Central

    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.

    2016-01-01

    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

  6. Clinical results of single-session bilateral medial patellar luxation repair in 26 small breed dogs

    PubMed Central

    Balogh, Daniel G.; Kramek, Betty

    2016-01-01

    Medical records of 26 small breed dogs treated with single-session bilateral medial patellar luxation repair were reviewed. Excluding dogs with complications associated with cranial cruciate ligament disease, 20/21 dogs with long-term follow-up achieved a complete or acceptable clinical recovery. The complication rate was not increased compared to that previously reported for unilateral patellar luxation repair. PMID:27041762

  7. Laser Cladding for Crack Repair of CMSX-4 Single-Crystalline Turbine Parts

    NASA Astrophysics Data System (ADS)

    Rottwinkel, Boris; Nölke, Christian; Kaierle, Stefan; Wesling, Volker

    2016-12-01

    The increase of the lifetime of modern single crystalline (SX) turbine blades is of high economic priority. The currently available repair methods using polycrystalline cladding of the damaged area do not address the issue of monocrystallinity and are restricted to few areas of the blade. The tip area of the blade is most prone to damage and undergoes the most wear, erosion and cracking during its lifetime. To repair such defects, the common procedure is to remove the whole tip with the damaged area and rebuild it by applying a polycrystalline solidification of the material. The repair of small cracks is conducted in the same way. To reduce repair cost, the investigation of a manufacturing process to repair these cracked areas while maintaining single-crystal solidification is of high interest as this does not diminish material properties and thereby its lifetime. To establish this single-crystal solidification, the realization of a directed temperature gradient is needed. The initial scope of this work is the computational prediction of the temperature field that arises and its verification during the process. The laser cladding process of CMSX-4 substrates was simulated and the necessary parameters calculated. These parameters were then applied to notched substrates and their microstructures analyzed. Starting with a simulation of the temperature field using ANSYS®, a process to repair parts of single crystalline nickel-based alloys was developed. It could be shown that damages to the tip area and cracks can be repaired by establishing a specific temperature gradient during the repair process in order to control the solidification process.

  8. Laser Cladding for Crack Repair of CMSX-4 Single-Crystalline Turbine Parts

    NASA Astrophysics Data System (ADS)

    Rottwinkel, Boris; Nölke, Christian; Kaierle, Stefan; Wesling, Volker

    2017-03-01

    The increase of the lifetime of modern single crystalline (SX) turbine blades is of high economic priority. The currently available repair methods using polycrystalline cladding of the damaged area do not address the issue of monocrystallinity and are restricted to few areas of the blade. The tip area of the blade is most prone to damage and undergoes the most wear, erosion and cracking during its lifetime. To repair such defects, the common procedure is to remove the whole tip with the damaged area and rebuild it by applying a polycrystalline solidification of the material. The repair of small cracks is conducted in the same way. To reduce repair cost, the investigation of a manufacturing process to repair these cracked areas while maintaining single-crystal solidification is of high interest as this does not diminish material properties and thereby its lifetime. To establish this single-crystal solidification, the realization of a directed temperature gradient is needed. The initial scope of this work is the computational prediction of the temperature field that arises and its verification during the process. The laser cladding process of CMSX-4 substrates was simulated and the necessary parameters calculated. These parameters were then applied to notched substrates and their microstructures analyzed. Starting with a simulation of the temperature field using ANSYS®, a process to repair parts of single crystalline nickel-based alloys was developed. It could be shown that damages to the tip area and cracks can be repaired by establishing a specific temperature gradient during the repair process in order to control the solidification process.

  9. Ku-dependent and Ku-independent end-joining pathways lead to chromosomal rearrangements during double-strand break repair in Saccharomyces cerevisiae.

    PubMed Central

    Yu, Xin; Gabriel, Abram

    2003-01-01

    Chromosomal double-strand breaks (DSBs) can be repaired by either homology-dependent or homology-independent pathways. Nonhomologous repair mechanisms have been relatively less well studied, despite their potential importance in generating chromosomal rearrangements. We have developed a Saccharomyces cerevisiae-based assay to identify and characterize homology-independent chromosomal rearrangements associated with repair of a unique DSB generated within an engineered URA3 gene. Approximately 1% of successfully repaired cells have accompanying chromosomal rearrangements consisting of large insertions, deletions, aberrant gene conversions, or other more complex changes. We have analyzed rearrangements in isogenic wild-type, rad52, yku80, and rad52 yku80 strains, to determine the types of events that occur in the presence or absence of these key repair proteins. Deletions were found in all strain backgrounds, but insertions were dependent upon the presence of Yku80p. A rare RAD52- and YKU80-independent form of deletion was present in all strains. These events were characterized by long one-sided deletions (up to 13 kb) and extensive imperfect overlapping sequences (7-22 bp) at the junctions. Our results demonstrate that the frequency and types of repair events depend on the specific genetic context. This approach can be applied to a number of problems associated with chromosome stability. PMID:12663527

  10. Single-incision laparoscopic total extraperitoneal repair for a Grynfeltt hernia: a case report

    PubMed Central

    2014-01-01

    Introduction A superior lumbar hernia, which is also known as a Grynfeltt hernia, is a rare abdominal wall defect that can be primary or secondary to trauma or orthopedic surgery. The anatomic location of a lumbar hernia makes diagnosis and repair challenging. We successfully repaired a lumbar hernia using a single-incision laparoscopic total extraperitoneal approach. To the best of our knowledge, this is the first report of the use of this surgical technique in the treatment of a primary Grynfeltt hernia. Case presentation A 76-year-old Taiwanese man presented to our hospital with a left lower bulging mass noted for over three months. Abdominal computed tomography revealed a left Grynfeltt hernia. We performed a single-incision laparoscopic total extraperitoneal repair. Our patient was discharged uneventfully on the fourth day after the operation. There was no evidence of recurrence after six months of follow-up. Conclusion A laparoscopic total extraperitoneal repair for a lumbar hernia provides an excellent operative view and minimal invasiveness. The single-incision technique also provides better cosmetic outcomes. Our experience suggests that the single-incision laparoscopic total extraperitoneal approach may be a feasible and safe alterative to conventional approaches in lumbar hernia repair. PMID:24428946

  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. Single-Port Laparoscopic Parastomal Hernia Repair with Modified Sugarbaker Technique

    PubMed Central

    Turingan, Isidro; Zajkowska, Marta; Tran, Kim

    2014-01-01

    Introduction: Laparoscopic parastomal hernia repair with modified Sugarbaker technique has become increasingly the operation of choice because of its low recurrence rates. This study aimed to assess feasibility, safety, and efficiency of performing the same operation with single-incision laparoscopic surgery. Materials and Methods: All patients referred from March 2010 to February 2013 were considered for single-port laparoscopic repair with modified Sugarbaker technique. A SILS port (Covidien, Norwalk, Connecticut, USA) was used together with conventional straight dissecting instruments and a 5.5- mm/52-cm/30° laparoscope. Important technical aspects include modified dissection techniques, namely, “inline” and “chopsticks” to overcome loss of triangulation, insertion of a urinary catheter into an ostomy for ostomy limb identification, safe adhesiolysis by avoiding electocautery, saline -jet dissection to demarcate tissue planes, dissection of an entire laparotomy scar to expose incidental incisional hernias, adequate mobilization of an ostomy limb for lateralization, and wide overlapping of defect with antiadhesive mesh. Results: Of 6 patients, 5 underwent single-port laparoscopic repair, and 1 (whose body mass index [BMI] of 39.4 kg/m2 did not permit SILS port placement) underwent multiport repair. Mean defect size was 10 cm, and mean mesh size was 660 cm2 with 4 patients having incidental incisional hernias repaired by the same mesh. Mean operation time was 270 minutes, and mean hospital stay was 4 days. Appliance malfunction ceased immediately, and pain associated with parastomal hernia disappeared. There was no recurrence with a follow-up of 2 to 36 months. Conclusion: Compared with multiport repair, single-port laparoscopic parastomal repair with modified Sugarbaker technique is safe and efficient, and it may eventually become the standard of care. PMID:24680140

  13. 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.

  14. Management of Infected Mesh After Abdominal Hernia Repair: Systematic Review and Single-Institution Experience.

    PubMed

    Shubinets, Valeriy; Carney, Martin J; Colen, David L; Mirzabeigi, Michael N; Weissler, Jason M; Lanni, Michael A; Braslow, Benjamin M; Fischer, John P; Kovach, Stephen J

    2017-06-01

    Mesh infection after abdominal hernia repair is a devastating complication that affects general and plastic surgeons alike. The purpose of this study was 3-fold: (1) to determine current evidence for treatment of infected abdominal wall mesh via systematic review of literature, (2) to analyze our single-institution experience with treatment of infected mesh patients, and (3) to establish a framework for how to approach this complex clinical problem. Literature search was performed using the Preferred Reporting Items for Systematic Reviews and Meta-analysis guidelines, followed by single-institution retrospective analysis of infected mesh patients. A total of 3565 abstracts and 92 full-text articles were reviewed. For qualitative and quantitative assessment, articles were subdivided on the basis of treatment approach: "conservative management," "excision of mesh with primary closure," "single-stage reconstruction," "immediate staged repair," and "repair in contaminated field." Evidence for each treatment approach is presented. At our institution, most patients (40/43) were treated by excision of infected mesh and single-stage reconstruction with biologic mesh. When the mesh was placed in a retrorectus or underlay fashion, 21.4% rate of hernia recurrence was achieved. Bridged repairs were highly prone to recurrence (88.9%; P = 0.001), but the bridging biologic mesh seemed to maintain domain and potentially contribute to a more effective repair in the future. Of the patients who underwent additional ("secondary") repairs after recurrence, 75% were eventually able to achieve "hernia-free" state. This study reviews the literature and our single-institution experience regarding treatment of infected abdominal wall mesh. Framework is developed for how to approach this complex clinical problem.

  15. [Rotator cuff repair: single- vs double-row. Clinical and biomechanical results].

    PubMed

    Baums, M H; Kostuj, T; Klinger, H-M; Papalia, R

    2016-02-01

    The goal of rotator cuff repair is a high initial mechanical stability as a requirement for adequate biological recovery of the tendon-to-bone complex. Notwithstanding the significant increase in publications concerning the topic of rotator cuff repair, there are still controversies regarding surgical technique. The aim of this work is to present an overview of the recently published results of biomechanical and clinical studies on rotator cuff repair using single- and double-row techniques. The review is based on a selective literature research of PubMed, Embase, and the Cochrane Database on the subject of the clinical and biomechanical results of single- and double-row repair. In general, neither the biomechanical nor the clinical evidence can recommend the use of a double-row concept for the treatment for every rotator cuff tear. Only tears of more than 3 cm seem to benefit from better results on both imaging and in clinical outcome studies compared with the use of single-row techniques. Despite a significant increase in publications on the surgical treatment of rotator cuff tears in recent years, the clinical results were not significantly improved in the literature so far. Unique information and algorithms, from which the optimal treatment of this entity can be derived, are still inadequate. Because of the cost-effectiveness and the currently vague evidence, the double-row techniques cannot be generally recommended for the repair of all rotator cuff tears.

  16. Single- and double-row repair for rotator cuff tears - biology and mechanics.

    PubMed

    Papalia, Rocco; Franceschi, Francesco; Vasta, Sebastiano; Zampogna, Biagio; Maffulli, Nicola; Denaro, Vincenzo

    2012-01-01

    We critically review the existing studies comparing the features of single- and double-row repair, and discuss suggestions about the surgical indications for the two repair techniques. All currently available studies comparing the biomechanical, clinical and the biological features of single and double row. Biomechanically, the double-row repair has greater performances in terms of higher initial fixation strength, greater footprint coverage, improved contact area and pressure, decreased gap formation, and higher load to failure. Results of clinical studies demonstrate no significantly better outcomes for double-row compared to single-row repair. Better results are achieved by double-row repair for larger lesions (tear size 2.5-3.5 cm). Considering the lack of statistically significant differences between the two techniques and that the double row is a high cost and a high surgical skill-dependent technique, we suggest using the double-row technique only in strictly selected patients. Copyright © 2012 S. Karger AG, Basel.

  17. Safety and Efficacy of Single Incision Laparoscopic Surgery for Total Extraperitoneal Inguinal Hernia Repair

    PubMed Central

    2011-01-01

    Almost 20 years after the first laparoscopic inguinal hernia repair was performed, single incision laparoscopic surgery (SILS™) is set to revolutionize minimally invasive surgery. However, the loss of triangulation must be overcome before the technique can be popularized. This study reports the first 100 laparoscopic total extraperitoneal hernia repairs using a single incision. The study cohort comprised 68 patients with a mean age of 44 (range, 18 to 83): 36 unilateral and 32 bilateral hernias. Twelve patients also underwent umbilical hernia repair with the Ventralex patch requiring no additional incisions. A 2.5-cm to 3-cm crescentic incision within the confines of the umbilicus was performed. Standard dissecting instruments and 52-cm/5.5-mm/300 laparoscope were used. Operation times were 50 minutes for unilateral and 80 minutes for bilateral. There was one conversion to conventional 3-port laparoscopic repair and none to open surgery. Outpatient surgery was achieved in all (except one). Analgesic requirements were minimal: 8 Dextropropoxyphene tablets (range, 0 to 20). There were no intraoperative or postoperative complications with a high patient satisfaction score. Single-incision laparoscopic hernia repair is safe and efficient simply by modifying dissection techniques (so-called “inline” and “vertical”). Comparable success can be obtained while negating the risks of bowel and vascular injuries from sharp trocars and achieving improved cosmetic results. PMID:21902942

  18. RAD50 Is Required for Efficient Initiation of Resection and Recombinational Repair at Random, γ-Induced Double-Strand Break Ends

    PubMed Central

    Westmoreland, Jim; Ma, Wenjian; Yan, Yan; Van Hulle, Kelly; Malkova, Anna; Resnick, Michael A.

    2009-01-01

    Resection of DNA double-strand break (DSB) ends is generally considered a critical determinant in pathways of DSB repair and genome stability. Unlike for enzymatically induced site-specific DSBs, little is known about processing of random “dirty-ended” DSBs created by DNA damaging agents such as ionizing radiation. Here we present a novel system for monitoring early events in the repair of random DSBs, based on our finding that single-strand tails generated by resection at the ends of large molecules in budding yeast decreases mobility during pulsed field gel electrophoresis (PFGE). We utilized this “PFGE-shift” to follow the fate of both ends of linear molecules generated by a single random DSB in circular chromosomes. Within 10 min after γ-irradiation of G2/M arrested WT cells, there is a near-synchronous PFGE-shift of the linearized circular molecules, corresponding to resection of a few hundred bases. Resection at the radiation-induced DSBs continues so that by the time of significant repair of DSBs at 1 hr there is about 1–2 kb resection per DSB end. The PFGE-shift is comparable in WT and recombination-defective rad52 and rad51 strains but somewhat delayed in exo1 mutants. However, in rad50 and mre11 null mutants the initiation and generation of resected ends at radiation-induced DSB ends is greatly reduced in G2/M. Thus, the Rad50/Mre11/Xrs2 complex is responsible for rapid processing of most damaged ends into substrates that subsequently undergo recombinational repair. A similar requirement was found for RAD50 in asynchronously growing cells. Among the few molecules exhibiting shift in the rad50 mutant, the residual resection is consistent with resection at only one of the DSB ends. Surprisingly, within 1 hr after irradiation, double-length linear molecules are detected in the WT and rad50, but not in rad52, strains that are likely due to crossovers that are largely resection- and RAD50-independent. PMID:19763170

  19. 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

  20. Nonresectional Single-Suture Leaflet Remodeling for Degenerative Mitral Regurgitation Facilitates Minimally Invasive Mitral Valve Repair

    PubMed Central

    MacArthur, John W.; Cohen, Jeffrey E.; Goldstone, Andrew B.; Fairman, Alexander S.; Edwards, Bryan B.; Hornick, Matthew A.; Atluri, Pavan; Woo, Y. Joseph

    2014-01-01

    Background Both leaflet resection and neochordal construction are effective mitral repair techniques, but they may become incrementally time-consuming when using minimally invasive approaches. We have used a single-suture leaflet-remodeling technique of inverting the prolapsed or flail segment tissue into the left ventricle. This repair is straightforward, expeditious, and facilitates a minimally invasive approach. Methods Ninety-nine patients with degenerative mitral regurgitation (MR) underwent a minimally invasive single-suture repair of the mitral valve from May 2007 through December 2012. Preoperative and perioperative echocardiograms as well as patient outcomes were analyzed and compared with those obtained from patients undergoing minimally invasive mitral valve repair using quadrangular resection at the same institution during the same period. Results All 99 patients had a successful mitral repair through a sternal-sparing minimally invasive approach. Ninety-one of the 99 patients had zero MR on postoperative echocardiogram, and 8 of 99 had trace to mild MR. Patients in the nonresectional group had significantly shorter cardiopulmonary bypass and cross-clamp times compared with the quadrangular resection group (115.8 ± 41.7 minutes versus 144.9 ± 38.2 minutes; p < 0.001; 76.2 ± 28.1 minutes versus 112.6 ± 33.5 minutes; p < 0.001, respectively). The mean length of stay was 7.5 ± 3 days. All patients were discharged alive and free from clinical symptoms of MR. There have been no reoperations for recurrent MR on subsequent average follow-up of 1 year. Conclusions An effective, highly efficient, and thus far durable single-suture mitral leaflet-remodeling technique facilitates minimally invasive repair of degenerative MR. PMID:23932318

  1. A multistep genomic screen identifies new genes required for repair of DNA double-strand breaks in Saccharomyces cerevisiae.

    PubMed

    McKinney, Jennifer Summers; Sethi, Sunaina; Tripp, Jennifer DeMars; Nguyen, Thuy N; Sanderson, Brian A; Westmoreland, James W; Resnick, Michael A; Lewis, L Kevin

    2013-04-15

    Efficient mechanisms for rejoining of DNA double-strand breaks (DSBs) are vital because misrepair of such lesions leads to mutation, aneuploidy and loss of cell viability. DSB repair is mediated by proteins acting in two major pathways, called homologous recombination and nonhomologous end-joining. Repair efficiency is also modulated by other processes such as sister chromatid cohesion, nucleosome remodeling and DNA damage checkpoints. The total number of genes influencing DSB repair efficiency is unknown. To identify new yeast genes affecting DSB repair, genes linked to gamma radiation resistance in previous genome-wide surveys were tested for their impact on repair of site-specific DSBs generated by in vivo expression of EcoRI endonuclease. Eight members of the RAD52 group of DNA repair genes (RAD50, RAD51, RAD52, RAD54, RAD55, RAD57, MRE11 and XRS2) and 73 additional genes were found to be required for efficient repair of EcoRI-induced DSBs in screens utilizing both MATa and MATα deletion strain libraries. Most mutants were also sensitive to the clastogenic chemicals MMS and bleomycin. Several of the non-RAD52 group genes have previously been linked to DNA repair and over half of the genes affect nuclear processes. Many proteins encoded by the protective genes have previously been shown to associate physically with each other and with known DNA repair proteins in high-throughput proteomics studies. A majority of the proteins (64%) share sequence similarity with human proteins, suggesting that they serve similar functions. We have used a genetic screening approach to detect new genes required for efficient repair of DSBs in Saccharomyces cerevisiae. The findings have spotlighted new genes that are critical for maintenance of genome integrity and are therefore of greatest concern for their potential impact when the corresponding gene orthologs and homologs are inactivated or polymorphic in human cells.

  2. Combination of Liechtenstein Repair with Herniorrhaphy in Open Inguinal Hernia Repair- A Prospective Observational Single Center Study

    PubMed Central

    Pukar, Mahesh

    2014-01-01

    Context: This study is about documentation of a technique which includes a combination of both hernioplasty and Herniorrhaphy, and its outcome in terms of recurrence rate and postoperative complications. It also compares the outcome of this method with routinely used techniques reported in the literature. Materials and Methods: LR with Herniorrhaphy was performed in the patients admitted with inguinal hernia under concerned surgeon. Their follow-up was assessed after 12 months. Incidences of recurrence rate and other postoperative complications like painful scar, atrophy of testis, urinary retention, hematoma, sinus and infection were noted and compared with other techniques of repair from published data. Statistical Analysis: was carried out by calculating the mean, standard deviation (SD), percentage and incidence rates. Results: LR with Herniorrhaphy performed in 475 patients showed recurrence rate of <<0.01% (n=1) and very low incidences of other postoperative complications like painful scar (0.01%, n=5), sinus (0%, n=0), atrophy of testis (0%, n=0), retention of urine (0.01%, n=6), hematoma (<<0.01%, n=1) and infection (0%, n=0); as compared to published data with different techniques. Conclusion: LR with Herniorrhaphy can be used for open inguinal hernia repair as the gold standard procedure as it has got low recurrence rate and other postoperative complications as compared to other techniques. However, the result of this study is based on the data from a single center, thus we recommend multicentric trials to test the efficacy of this technique. PMID:25478390

  3. Wound Repair: Toward Understanding and Integration of Single-Cell and Multicellular Wound Responses

    PubMed Central

    Sonnemann, Kevin J.; Bement, William M.

    2016-01-01

    The importance of wound healing to medicine and biology has long been evident, and consequently, wound healing has been the subject of intense investigation for many years. However, several relatively recent developments have added new impetus to wound repair research: the increasing application of model systems; the growing recognition that single cells have a robust, complex, and medically relevant wound healing response; and the emerging recognition that different modes of wound repair bear an uncanny resemblance to other basic biological processes such as morphogenesis and cytokinesis. In this review, each of these developments is described, and their significance for wound healing research is considered. In addition, overlapping mechanisms of single-cell and multicellular wound healing are highlighted, and it is argued that they are more similar than is often recognized. Based on this and other information, a simple model to explain the evolutionary relationships of cytokinesis, single-cell wound repair, multicellular wound repair, and developmental morphogenesis is proposed. Finally, a series of important, but as yet unanswered, questions is posed. PMID:21721944

  4. Self-repairing in single-walled carbon nanotubes by heat treatment

    NASA Astrophysics Data System (ADS)

    Jiang, Jin-Wu; Wang, Jian-Sheng

    2010-09-01

    Structure transformation by heat treatment in single-walled carbon nanotubes (SWCNT) is investigated using molecular dynamics simulation. The critical temperature for the collapse of pure SWCNT is as high as 4655 K due to strong covalent carbon-carbon bonding. Above 2000 K, the cross section of SWCNT changes from circle to ellipse. The self-repairing capability is then investigated and two efficient processes are observed for the SWCNT to repair themselves. (1) In the first mechanism, vacancy defects aggregate to form a bigger hole, and a bottleneck junction is constructed nearby. (2) In the second mechanism, a local curvature is generated around the isolate vacancy to smooth the SWCNT. Benefit from the powerful self-repairing capability, defective SWCNT can seek a stable configuration at high temperatures; thus the critical temperature for collapse is insensitive to the vacancy defect density.

  5. 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. Copyright 2013, SLACK Incorporated.

  6. Single incision power optimizing cost-effective (SPOC) distal biceps repair.

    PubMed

    Tanner, Cary; Johnson, Toby; Muradov, Pavel; Husak, Lisa

    2013-03-01

    The purpose of this study was to review the results of a single anterior incision distal biceps tendon repair that reattaches the tendon to its posterior anatomic insertion site. We hypothesize this repair maximizes the supination torque of the biceps muscle throughout the full arc of forearm rotation. A consecutive series of patients with distal biceps tears were treated using a technique that reattaches the distal biceps tendon to the posterior radial surface similar to a 2-incision repair, which optimizes the biceps moment arm in all forearm positions including maximum supination. This method of distal biceps reattachment has been utilized in our practice since December 2008 on 40 distal biceps tendon repairs. Biodex testing was used to quantify the peak supination torque, the supination work, and the power of supination at each degree of forearm rotation and included on patients with a minimum clinical follow up of 12 months. Range of motion was also recorded. Thirty patients met the inclusion criteria. Three patients, 2 of whom were lost to follow-up and 1 with bilateral repairs, were not included in this study. Seventeen of the remaining 27 patients completed strength testing using a Biodex Isokinetic Testing machine. Supination strength averaged 91% and 91% of the uninjured side at 60 and 120 deg/sec, respectively. Twenty-five (93%) patients reported no pain and had returned to work or normal activities. A single anterior incision distal biceps tendon repair that maximizes supination torque throughout full forearm rotation has been utilized. No specialized anchors or equipment are required. Level IV, Case Series, Treatment Study. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  7. Functional Outcomes after Double Row Versus Single Row Rotator Cuff Repair

    PubMed Central

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

    2015-01-01

    Objectives: The effect of single row (SR) versus double row (DR) rotator cuff repair on functional outcomes was examined in a prospective randomized design. Methods: Fifty patients were randomized to DR or SR repairs; 39 patients (13 women, 26 men, 23 SR, 16 DR, age 62±7 yr) were assessed at an average of 2.2±1.6 yr after surgery (range 1-7 yr; tear size 17 medium, 13 large, 9 massive). The following data were recorded prior to surgery and at follow-up: Penn, ASES and Simple Shoulder Test (SST) scores; range of motion (ROM) for shoulder flexion, external rotation (ER) at 0º and 90º abduction, and internal rotation (IR) at 90º abduction; shoulder strength (Lafayette Manual Muscle Tester) in empty and full can tests, abduction and ER at 0º abduction. Treatment (SR vs. DR) by Time (pre-op vs. post-op) mixed model analysis of variance was used to assess the effect of rotator cuff repair. It was estimated that with 20 patients per group a 10-point difference in improvement in ASES scores between SR and DR treatments could be detected at an alpha level of 0.05 with 80% power. Results: Outcome Scores: RC repair markedly improved Penn, ASES and SST scores (P<0.001), with similar improvement between single versus double row repairs (Treatment by Time P=.49 to P=.67), and excellent scores at follow-up (Double Row vs. Single Row: Penn 91±11 vs. 91±12, P=.98; ASES 92±9 vs 87 ±15, P=.24; SST 11.2±1.2 vs. 11.4±1.0, P=.58). ROM: Patients with DR repairs lost ER ROM at 0º abduction (pre-op to final follow-up 7±10º loss, P=.013). ER ROM did not change with SR repair (3.9±15.6º gain, P=.24; Treatment by Time P=.017). This effect was not apparent for ER ROM at 90º abduction (Treatment by Time P=.26). IR ROM improved from pre-op to final follow-up (P<0.01, SR 17±18º, DR 13±23º, Treatment by Time P=.31). Strength: RC repair markedly improved strength in Empty Can (51%), Full Can (54%), Abduction (45%) and ER (31 %) strength (all P<.001), with no difference between

  8. Single-stage soft tissue reconstruction and orbital fracture repair for complex facial injuries.

    PubMed

    Wu, Peng Sen; Matoo, Reshvin; Sun, Hong; Song, Li Yuan; Kikkawa, Don O; Lu, Wei

    2017-02-01

    Orbital fractures with open periorbital wounds cause significant morbidity. Timing of debridement with fracture repair and soft tissue reconstruction is controversial. This study focuses on the efficacy of early single-stage repair in combined bony and soft tissue injuries. Retrospective review. Twenty-three patients with combined open soft tissue wounds and orbital fractures were studied for single-stage orbital reconstruction and periorbital soft tissue repair. Inclusion criteria were open soft tissue wounds with clinical and radiographic evidence of orbital fractures and repair performed within 48 h after injury. Surgical complications and reconstructive outcomes were assessed over 6 months. The main outcome measures were enophthalmos, pre- and post-CT imaging of orbits, scar evaluation, presence of diplopia, and eyelid position. Enophthalmos was corrected in 16/19 cases and improved in 3/19 cases. 3D reconstruction of CT images showed markedly improved orbital alignment with objective measurements of the optic foramen to cornea distance (mm) in reconstructed orbits relative to intact orbits of 0.66, 95% confidence interval [CI] (lower 0.33, upper 0.99) mm. The mean baseline of Stony Brook Scar Evaluation Scale was 0.6, 95%CI (0.30-0.92), and for 6 months, the mean score was 3.4, 95%CI (3.05-3.73). Residual diplopia in secondary gazes was present in two patients; one patient had ectropion. Complications included one case of local wound infection. An early single-stage repair of combined soft tissue and orbital fractures yields satisfactory functional and aesthetic outcomes. Complications are low and likely related to trauma severity. Copyright © 2016 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  9. p53 isoform Δ113p53/Δ133p53 promotes DNA double-strand break repair to protect cell from death and senescence in response to DNA damage.

    PubMed

    Gong, Lu; Gong, Hongjian; Pan, Xiao; Chang, Changqing; Ou, Zhao; Ye, Shengfan; Yin, Le; Yang, Lina; Tao, Ting; Zhang, Zhenhai; Liu, Cong; Lane, David P; Peng, Jinrong; Chen, Jun

    2015-03-01

    The inhibitory role of p53 in DNA double-strand break (DSB) repair seems contradictory to its tumor-suppressing property. The p53 isoform Δ113p53/Δ133p53 is a p53 target gene that antagonizes p53 apoptotic activity. However, information on its functions in DNA damage repair is lacking. Here we report that Δ113p53 expression is strongly induced by γ-irradiation, but not by UV-irradiation or heat shock treatment. Strikingly, Δ113p53 promotes DNA DSB repair pathways, including homologous recombination, non-homologous end joining and single-strand annealing. To study the biological significance of Δ113p53 in promoting DNA DSB repair, we generated a zebrafish Δ113p53(M/M) mutant via the transcription activator-like effector nuclease technique and found that the mutant is more sensitive to γ-irradiation. The human ortholog, Δ133p53, is also only induced by γ-irradiation and functions to promote DNA DSB repair. Δ133p53-knockdown cells were arrested at the G2 phase at the later stage in response to γ-irradiation due to a high level of unrepaired DNA DSBs, which finally led to cell senescence. Furthermore, Δ113p53/Δ133p53 promotes DNA DSB repair via upregulating the transcription of repair genes rad51, lig4 and rad52 by binding to a novel type of p53-responsive element in their promoters. Our results demonstrate that Δ113p53/Δ133p53 is an evolutionally conserved pro-survival factor for DNA damage stress by preventing apoptosis and promoting DNA DSB repair to inhibit cell senescence. Our data also suggest that the induction of Δ133p53 expression in normal cells or tissues provides an important tolerance marker for cancer patients to radiotherapy.

  10. Biomechanical Comparison of Arthroscopic Single- and Double-Row Repair Techniques for Acute Bony Bankart Lesions.

    PubMed

    Spiegl, Ulrich J; Smith, Sean D; Todd, Jocelyn N; Coatney, Garrett A; Wijdicks, Coen A; Millett, Peter J

    2014-08-01

    Single- and double-row arthroscopic reconstruction techniques for acute bony Bankart lesions have been described in the literature. The double-row fixation technique would provide superior reduction and stability of a simulated bony Bankart lesion at time zero in a cadaveric model compared with the single-row technique. Controlled laboratory study. Testing was performed on 14 matched pairs of glenoids with simulated bony Bankart fractures with a defect width of 25% of the glenoid diameter. Half of the fractures were repaired with a double-row technique, while the contralateral glenoids were repaired with a single-row technique. The quality of fracture reduction was measured with a coordinate measuring machine. To determine the biomechanical stability of the repairs, specimens were preconditioned with 10 sinusoidal cycles between 5 and 25 N at 0.1 Hz and then pulled to failure in the anteromedial direction at a rate of 5 mm/min. Loads at 1 mm and 2 mm of fracture displacement were determined. The double-row technique required significantly higher forces to achieve fracture displacements of 1 mm (mean, 60.6 N; range, 39.0-93.3 N; P = .001) and 2 mm (mean, 94.4 N; range, 43.4-151.2 N; P = .004) than the single-row technique (1 mm: mean, 30.2 N; range, 14.0-54.1 N and 2 mm: mean, 63.7 N; range, 26.6-118.8 N). Significantly reduced fracture displacement was seen after double-row repair for both the unloaded condition (mean, 1.1 mm; range, 0.3-2.4 mm; P = .005) and in response to a 10-N anterior force applied to the defect (mean, 1.6 mm; range, 0.5-2.7 mm; P = .001) compared with single-row repair (unloaded: mean, 2.1 mm; range, 1.3-3.4 mm and loaded: mean, 3.4 mm; range, 1.9-4.7 mm). The double-row fixation technique resulted in improved fracture reduction and superior stability at time zero in this cadaveric model. This information may influence the surgical technique used to treat large osseous Bankart fractures and the postoperative rehabilitation protocols

  11. 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

  12. Single-stage repair of aneurysm of the ascending aorta associated with aortic coarctation.

    PubMed

    Attaran, Saina; Felderhoff, Jeremy; Westwood, Mark A; Awad, Wael I

    2010-08-01

    A 38-year-old man with a history of uncontrolled hypertension was investigated for atypical chest pains and found to have an aneurysm of the ascending aorta and a coexisting coarctation of the aorta. The timing and sequence of surgical repair of these 2 pathologies are controversial. We report an elective single-stage operation in which the ascending aorta was replaced and an extracardiac bypass from the ascending to the descending aorta was performed with excellent results.

  13. Single-stage surgical repair of a complex pathology in Williams syndrome.

    PubMed

    Feng, Tong; Zhi-Qiang, Li; Ying-Long, Liu

    2014-02-01

    Williams syndrome is caused by a gene deletion of chromosome 7. A majority of the cases are sporadic with typical facial appearance, cardiac anomalies, and mental retardation. We report a rare case of Williams syndrome associated with supravalvular aortic stenosis, subvalvular aortic membrane, mitral regurgitation, aortic coarctation, and patent ductus arteriosus. The patient had undergone a single-stage surgical repair with satisfactory results at 5 months of follow-up.

  14. 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

  15. 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).

  16. Medium to long term results following single stage Snodgrass hypospadias repair.

    PubMed

    Aslam, R; Campbell, K; Wharton, S; Bracka, A

    2013-11-01

    The Snodgrass technique for primary hypospadias repair was described in 1994 and involves dorsal incision and tubularisation of the urethral plate distal to the meatus. While the advantages of good short-term outcome and good cosmesis have been reported, there is little data on long-term results in patients who have undergone a Snodgrass repair as a primary procedure for hypospadias. Our aim is to retrospectively review our medium to long-term results of primary tubularised incised-plate urethroplasty for hypospadias repair over a two-year period with up to eight-year follow-up. We conducted a case note review of 74 patients who had undergone single-stage Snodgrass hypospadias repair, performed by a single surgeon (AB), from April 2000 to January 2003. The mean documented follow up was 56 months (3-103 months). The mean age of patients at time of surgery was three and a half years. 95% (70) of patients had a distal (glanular, coronal, sub-coronal, distal shaft) meatus and 5% (4) had a proximal (mid-shaft) meatus. The overall complication rate was 7% (5). Two patients developed fistulae, which was noted and repaired at six months post-op with no further surgical intervention required. One patient underwent an EUA and meatal advancement glansplasty at 6 months for mild glanular dehiscence. Two further patients required EUA and dilatation procedures at two and three years respectively, both for mild meatal stenosis. Again, no further intervention was required. From a cosmetic perspective, two patients were noted to have some residual bulkiness of the skin around the corona and a further two patients were noted to have a small meatus, but with no functional symptoms. Our study has shown a low long-term complication rate in patients undergoing Snodgrass repair as a primary procedure for distal and midshaft hypospadias repair. This supports the results of earlier studies that have shown good functional and cosmetic outcome in the short-term for this procedure which

  17. 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

  18. Endovascular repair of thoracic and abdominal aortic ruptures: a single-center experience.

    PubMed

    İslim, Filiz; Erbahçeci Salık, Aysun; Güven, Koray; Bakuy, Vedat; Çukurova, Zafer

    2014-01-01

    We aimed to present our preliminary single-center experience of the endovascular management of thoracic and abdominal aortic ruptures. Between September 2010 and May 2012, 11 consecutive patients (nine males, two females; age range, 26-80 years) with thoracic and abdominal aortic ruptures underwent endovascular repair in our unit. Thoracoabdominal computed tomography (CT) angiography was performed for diagnosis and follow-up. Patients were selected for endovascular repair by a cardiovascular surgeon, anesthesiologist, and interventional radiologist. All repairs were performed using commercially available stent-grafts. The patients were followed up with CT angiography before discharge, at six months, and yearly thereafter. Three patients died by day 30. One patient died due to an unsuccessful procedure and hemodynamic instability; two patients died because of comorbidities. The other eight patients were followed for six to 24 months after the procedure. No endoleaks or late ruptures were observed during the follow-up period. The patient with iatrogenic thoracic aortic rupture developed paraplegia after the procedure. Reduced mortality due to aortic rupture has been reported with the expanding use of endovascular repair. Reports of small centers are important because of the rarity of these pathologies, and because transferring patients with aortic rupture to a referral center is not usually possible.

  19. DNA single-strand break repair is impaired in aprataxin-related ataxia.

    PubMed

    Hirano, Makito; Yamamoto, Aya; Mori, Toshio; Lan, Li; Iwamoto, Taka-aki; Aoki, Masashi; Shimada, Keiji; Furiya, Yoshiko; Kariya, Shingo; Asai, Hirohide; Yasui, Akira; Nishiwaki, Tomohisa; Imoto, Kyoko; Kobayashi, Nobuhiko; Kiriyama, Takao; Nagata, Tetsuya; Konishi, Noboru; Itoyama, Yasuto; Ueno, Satoshi

    2007-02-01

    Early-onset ataxia with ocular motor apraxia and hypoalbuminemia (EAOH)/ataxia with oculomotor apraxia type 1 (AOA1) is an autosomal recessive form of cerebellar ataxia. The causative protein for EAOH/AOA1, aprataxin (APTX), interacts with X-ray repair cross-complementing 1 (XRCC1), a scaffold DNA repair protein for single-strand breaks (SSBs). The goal of this study was to prove the functional involvement of APTX in SSB repair (SSBR). We visualized the SSBR process with a recently developed laser irradiation system that allows real-time observation of SSBR proteins and with a local ultraviolet-irradiation system using a XPA-UVDE cell line that repairs DNA lesions exclusively via SSBR. APTX was knocked down using small interference RNA in the cells. Oxidative stress-induced DNA damage and cell death were assessed in EAOH fibroblasts and cerebellum. Our systems showed the XRCC1-dependent recruitment of APTX to SSBs. SSBR was impaired in APTX-knocked-down cells. Oxidative stress in EAOH fibroblasts readily induced SSBs and cell death, which were blocked by antioxidants. Accumulated oxidative DNA damage was confirmed in EAOH cerebellum. This study provides the first direct evidence for the functional involvement of APTX in SSBR and in vivo DNA damage in EAOH/AOA1, and suggests a benefit of antioxidant treatment.

  20. Viral interference with DNA repair by targeting of the single-stranded DNA binding protein RPA.

    PubMed

    Banerjee, Pubali; DeJesus, Rowena; Gjoerup, Ole; Schaffhausen, Brian S

    2013-10-01

    Correct repair of damaged DNA is critical for genomic integrity. Deficiencies in DNA repair are linked with human cancer. Here we report a novel mechanism by which a virus manipulates DNA damage responses. Infection with murine polyomavirus sensitizes cells to DNA damage by UV and etoposide. Polyomavirus large T antigen (LT) alone is sufficient to sensitize cells 100 fold to UV and other kinds of DNA damage. This results in activated stress responses and apoptosis. Genetic analysis shows that LT sensitizes via the binding of its origin-binding domain (OBD) to the single-stranded DNA binding protein replication protein A (RPA). Overexpression of RPA protects cells expressing OBD from damage, and knockdown of RPA mimics the LT phenotype. LT prevents recruitment of RPA to nuclear foci after DNA damage. This leads to failure to recruit repair proteins such as Rad51 or Rad9, explaining why LT prevents repair of double strand DNA breaks by homologous recombination. A targeted intervention directed at RPA based on this viral mechanism could be useful in circumventing the resistance of cancer cells to therapy.

  1. Single port laparoscopic repair of paediatric inguinal hernias: Our experience at a secondary care centre

    PubMed Central

    Kumar, Ameet; Ramakrishnan, T S

    2013-01-01

    BACKGROUND: Congenital inguinal hernias are a common paediatric surgical problem and herniotomy through a groin incision is the gold standard. Over the last 2 decades minimally invasive surgery (MIS) has challenged this conventional surgery. Over a period, MIS techniques have evolved to making it more minimally invasive – from 3 to 2 and now single port technique. All studies using single port technique are from tertiary care centres. We used a modification of the technique described by Ozgediz et al. and reviewed the clinical outcome of this novel procedure and put forth our experience at a secondary level hospital. MATERIALS AND METHODS: Prospective review of 37 hernias in 31 children (29 male and 2 female) (8 months - 13 years) performed laparoscopically by a single surgeon at a single centre between September 2007 and June 2010. Under laparoscopic guidance, the internal ring was encircled extraperitoneally using a 2-0 non-absorbable suture and knotted extraperitoneally. Data analyzed included operating time, ease of procedure, occult patent processus vaginalis (PPV), complications, and cosmesis. RESULTS: Sixteen right (52%), 14 left (45%) and 1 bilateral hernia (3%) were repaired. Five unilateral hernias (16.66%), all left, had a contralateral PPV that was repaired (P = 0.033). Mean operative time for a unilateral and bilateral repair were 13.20 (8–25) and 20.66 min (17 -27 min) respectively. Only one of the repairs (2.7%) recurred and another had a post operative hydrocoele (2.7%). One case (2.7%) needed an additional port placement due to inability to reduce the contents of hernia completely. There were no stitch abscess/granulomas, obvious spermatic cord injuries, testicular atrophy, or nerve injuries. CONCLUSION: Single port laparoscopic inguinal hernia repair can be safely done in the paediatric population. It permits extension of benefits of minimal access surgery to patients being managed at secondary level hospitals with limited resources. The

  2. Fistula after single-stage primary hypospadias repair - A systematic review of the literature.

    PubMed

    Hardwicke, J T; Bechar, J A; Hodson, J; Osmani, O; Park, A J

    2015-12-01

    The reporting of fistula after hypospadias repair varies greatly in the worldwide literature, with incidence ranging from 0% to over 35%. With multiple techniques employed within a heterogeneous patient cohort, to date, no "average" incidence of fistula has been reported. A systematic review of the contemporary English-language literature from 2005 to 2015 identifying articles reporting complications after primary, single-stage hypospadias repair (the most commonly performed hypospadias operation) was performed. Identified reports were reviewed according to the Consolidated Standards of Reporting Trials (CONSORT) and the Methodological Index or Non-Randomized Studies (MINORS). A random effects analysis model was produced, in order to calculate a pooled outcome rates across the included studies. Separate models were then produced for subgroups of studies, with the resulting pooled rates compared. After application of inclusion and exclusion criteria, 44 articles progressed to the final analysis. A total of 6603 patients were included. The incidence of fistula was 7.5% (95% CI: 5.8-9.4), stricture or stenosis 4.4% (95% CI: 3.1-5.8) and dehiscence 2.1% (95% CI: 1.3-3.1). With pooled proportions of complications from over 6600 patients over a 10-year period, a standard may be set for outcomes after single-stage primary hypospadias repair for surgeons to audit their own outcomes against. Copyright © 2015 British Association of Plastic, Reconstructive and Aesthetic Surgeons. Published by Elsevier Ltd. All rights reserved.

  3. A tetrad of bicuspid aortic valve association: A single-stage repair

    PubMed Central

    Barik, Ramachandra; Patnaik, A. N.; Mishra, Ramesh C.; Kumari, N. Rama; Gulati, A. S.

    2012-01-01

    We report a 27 years old male who presented with a combination of both congenital and acquired cardiac defects. This syndrome complex includes congenital bicuspid aortic valve, Seller's grade II aortic regurgitation, juxta- subclavian coarctation, stenosis of ostium of left subclavian artery and ruptured sinus of Valsalva aneurysm without any evidence of infective endocarditis. This type of constellation is extremely rare. Neither coarctation of aorta with left subclavian artery stenosis nor the rupture of sinus Valsalva had a favorable pathology for percutaneus intervention. Taking account into morbidity associated with repeated surgery and anesthesia patient underwent a single stage surgical repair of both the defects by two surgical incisions. The approaches include median sternotomy for rupture of sinus of Valsalva and lateral thoracotomy for coarctation with left subclavian artery stenosis. The surgery was uneventful. After three months follow up echocardiography showed mild residual gradient across the repaired coarctation segment, mild aortic regurgitation and no residual left to right shunt. This patient is under follow up. This is an extremely rare case of single stage successful repair of coarctation and rupture of sinus of Valsalva associated with congenital bicuspid aortic valve. PMID:22629035

  4. New technique for single-staged repair of aortic coarctation and coexisting cardiac disorder.

    PubMed

    Korkmaz, Askin Ali; Guden, Mustafa; Onan, Burak; Tarakci, Sevim Indelen; Demir, Ali Soner; Sagbas, Ertan; Sarikaya, Tugay

    2011-01-01

    The management of adults with aortic coarctation and a coexisting cardiac disorder is still a surgical challenge. Single-staged procedures have lower postoperative morbidity and mortality rates than do 2-staged procedures. We present our experience with arch-to-descending aorta bypass grafting in combination with intracardiac or ascending aortic aneurysm repair.From October 2004 through April 2010, 5 patients (4 men, 1 woman; mean age, 45.8 ± 9.4 yr) underwent anatomic bypass grafting of the arch to the descending aorta through a median sternotomy and concomitant repair of an intracardiac disorder or an ascending aortic aneurysm. Operative indications included coarctation of the aorta in all cases, together with severe mitral insufficiency arising from damaged chordae tendineae in 2 patients, ascending aortic aneurysm with aortic regurgitation in 2 patients, and coronary artery disease in 1 patient. Data from early and midterm follow-up were reviewed.There was no early or late death. Follow-up was complete for all patients, and the mean follow-up period was 34.8 ± 18 months (range, 18 mo-5 yr). All grafts were patent. No late graft-related sequelae or reoperations were observed.For single-staged repair of aortic coarctation with a coexistent cardiac disorder, we propose arch-to-descending aorta bypass through a median sternotomy as an alternative for selected patients.

  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. Single-Stage Cartilage Repair Using Platelet-Rich Fibrin Scaffolds With Autologous Cartilaginous Grafts.

    PubMed

    Wong, Chin-Chean; Chen, Chih-Hwa; Chan, Wing P; Chiu, Li-Hsuan; Ho, Wei-Pin; Hsieh, Fon-Jou; Chen, You-Tzung; Yang, Tsung-Lin

    2017-09-01

    To avoid complicated procedures requiring in vitro chondrocyte expansion for cartilage repair, the development of a culture-free, 1-stage approach combining platelet-rich fibrin (PRF) and autologous cartilage grafts may be the solution. To develop a feasible 1-step procedure to combine PRF and autologous cartilage grafts for articular chondral defects. Controlled laboratory study Methods: The chemotactic effects of PRF on chondrocytes harvested from the primary culture of rabbit cartilage were evaluated in vitro and ex vivo. The rabbit chondrocytes were cultured with different concentrations of PRF media and evaluated for their cell proliferation, chondrogenic gene expression, cell viability, and extracellular matrix synthesis abilities. For the in vivo study, the chondral defects were created on established animal models of rabbits. The gross anatomy, histology, and objective scores were evaluated to validate the treatment results. PRF improved the chemotaxis, proliferation, and viability of the cultured chondrocytes. The gene expression of the chondrogenic markers, including type II collagen and aggrecan, revealed that PRF induced the chondrogenic differentiation of cultured chondrocytes. PRF increased the formation and deposition of the cartilaginous matrix produced by cultured chondrocytes. The efficacy of PRF on cell viability was comparable with that of fetal bovine serum. In animal disease models, morphologic, histological, and objectively quantitative evaluation demonstrated that PRF combined with cartilage granules was feasible in facilitating chondral repair. PRF enhances the migration, proliferation, viability, and differentiation of chondrocytes, thus showing an appealing capacity for cartilage repair. The data altogether provide evidence to confirm the feasibility of 1-stage, culture-free method of combining PRF and autologous cartilage graft for repairing articular chondral defects. The single-stage, culture-free method of combining PRF and autologous

  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. [Inflammatory aortic aneurysms: Single center experiences with endovascular repair of inflammatory abdominal aortic aneurysms].

    PubMed

    Strube, H; Treitl, M; Reiser, M; Steckmeier, B; Sadeghi-Azandaryani, M

    2010-10-01

    We report our single center experience of renal function, hydronephrosis and changes in perianeurysmal fibrosis (PAF) after endovascular repair (EVAR) of inflammatory abdominal aortic aneurysms (IAAA). A total of 6 patients were treated for IAAA with EVAR and the technical success was 100%. During the follow-up period 5 patients showed regression of PAF and 1 patient showed minor progression of PAF on computed tomography scans. In 2 patients hydronephrosis was regressive postoperatively but no patients died within 30 days. There were no secondary complications to report and no secondary intervention was necessary. In the long-term course one patient exhibited complete regression of PAF.In appropriate cases EVAR is a safe method for aneurysm repair for IAAA. In patients with acute inflammation or hydronephrosis individual treatment concepts are required.

  9. Percutaneous suturing technique and single-site umbilical laparoscopic repair of a Morgagni hernia: Review of three cases.

    PubMed

    Zouari, M; Jallouli, M; Bendhaou, M; Zitouni, H; Mhiri, R

    2015-12-01

    Morgagni hernias are uncommon, accounting for only 1-2% of all congenital diaphragmatic hernia. Minimally invasive surgery is today the gold standard treatment. We present a technique using percutaneous suturing and single-site umbilical laparoscopic repair of Morgagni hernia in three children. Recovery was uneventful in all three patients. There was no recurrence and the chest radiograph remained normal during the postoperative follow-up. The percutaneous suturing technique and single-site umbilical laparoscopic repair of a Morgagni hernia is an easy and effective alternative to standard laparoscopic repair.

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

    PubMed

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

    2015-08-01

    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.

  11. 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

  12. PARP-mediated repair, homologous recombination, and back-up non-homologous end joining-like repair of single-strand nicks.

    PubMed

    Metzger, Michael J; Stoddard, Barry L; Monnat, Raymond J

    2013-07-01

    Double-strand breaks (DSBs) in chromosomal DNA can induce both homologous recombination (HR) and non-homologous end-joining (NHEJ). Recently we showed that single-strand nicks induce HR with a significant reduction in toxicity and mutagenic effects associated with NHEJ. To further investigate the differences and similarities of DSB- and nick-induced repair, we used an integrated reporter system in human cells to measure HR and NHEJ produced by the homing endonuclease I-AniI and a designed 'nickase' variant that nicks the same target site, focusing on the PARP and HR repair pathways. PARP inhibitors, which block single-strand break repair, increased the rate of nick-induced HR up to 1.7-fold but did not affect DSB-induced HR or mutNHEJ. Additionally, expression of the PALB2 WD40 domain in trans acted as a dominant-negative inhibitor of both DSB- and nick-induced HR, sensitized cells to PARP inhibition, and revealed an alternative mutagenic repair pathway for nicks. Thus, while both DSB- and nick-induced HR use a common pathway, their substrates are differentially processed by cellular factors. These results also suggest that the synthetic lethality of PARP and BRCA may be due to repair of nicks through an error prone, NHEJ-like mechanism that is active when both PARP and HR pathways are blocked.

  13. Laparoendoscopic single-site versus conventional laparoscopic total extraperitoneal hernia repair: a prospective randomized clinical trial.

    PubMed

    Tsai, Yao-Chou; Ho, Chen-Hsun; Tai, Huai-Ching; Chung, Shiu-Dong; Chueh, Shih-Chieh

    2013-12-01

    This study aimed to compare laparoendoscopic single-site (LESS) total extraperitoneal (TEP) repair with conventional laparoscopic TEP repair for the treatment of inguinal hernias. To date, no other studies have compared the LESS and conventional laparoscopic TEP approaches for the treatment of inguinal hernia in a prospective randomized study setting. For this study, 100 patients undergoing inguinal hernia repair were prospectively randomized into either the LESS TEP group or the conventional laparoscopic TEP group. Pre-, intra-, and postoperative factors were recorded. The primary end point was postoperative pain. The patients were interviewed at outpatient clinics at 1 week, 3 months, and 6 months postoperatively. The demographic data were comparable between the two groups. The median operative time was longer in the LESS TEP group (63.5 min) than in the conventional TEP group (50.5 min) (p = 0.001). No conversion was performed in either group. The mean pain score 2 h postoperatively during rest was significantly higher in the conventional TEP group than in the LESS TEP group (3.9 vs. 2.6; p = 0.02). The postoperative results were comparable between the groups in terms of analgesic requirements, systemic stress responses, complications, and postoperative convalescence. The LESS TEP technique is associated with a longer operative time but offers the minor benefit of a reduction in immediate postoperative pain.

  14. TDP1 facilitates chromosomal single-strand break repair in neurons and is neuroprotective in vivo.

    PubMed

    Katyal, Sachin; el-Khamisy, Sherif F; Russell, Helen R; Li, Yang; Ju, Limei; Caldecott, Keith W; McKinnon, Peter J

    2007-11-14

    Defective Tyrosyl-DNA phosphodiesterase 1 (TDP1) can cause spinocerebellar ataxia with axonal neuropathy (SCAN1), a neurodegenerative syndrome associated with marked cerebellar atrophy and peripheral neuropathy. Although SCAN1 lymphoblastoid cells show pronounced defects in the repair of chromosomal single-strand breaks (SSBs), it is unknown if this DNA repair activity is important for neurons or for preventing neurodegeneration. Therefore, we generated Tdp1-/- mice to assess the role of Tdp1 in the nervous system. Using both in vitro and in vivo assays, we found that cerebellar neurons or primary astrocytes derived from Tdp1-/- mice display an inability to rapidly repair DNA SSBs associated with Top1-DNA complexes or oxidative damage. Moreover, loss of Tdp1 resulted in age-dependent and progressive cerebellar atrophy. Tdp1-/- mice treated with topotecan, a drug that increases levels of Top1-DNA complexes, also demonstrated significant loss of intestinal and hematopoietic progenitor cells. These data indicate that TDP1 is required for neural homeostasis, and reveal a widespread requisite for TDP1 function in response to acutely elevated levels of Top1-associated DNA strand breaks.

  15. TDP1 facilitates chromosomal single-strand break repair in neurons and is neuroprotective in vivo

    PubMed Central

    Katyal, Sachin; El-Khamisy, Sherif F; Russell, Helen R; Li, Yang; Ju, Limei; Caldecott, Keith W; McKinnon, Peter J

    2007-01-01

    Defective Tyrosyl-DNA phosphodiesterase 1 (TDP1) can cause spinocerebellar ataxia with axonal neuropathy (SCAN1), a neurodegenerative syndrome associated with marked cerebellar atrophy and peripheral neuropathy. Although SCAN1 lymphoblastoid cells show pronounced defects in the repair of chromosomal single-strand breaks (SSBs), it is unknown if this DNA repair activity is important for neurons or for preventing neurodegeneration. Therefore, we generated Tdp1−/− mice to assess the role of Tdp1 in the nervous system. Using both in vitro and in vivo assays, we found that cerebellar neurons or primary astrocytes derived from Tdp1−/− mice display an inability to rapidly repair DNA SSBs associated with Top1–DNA complexes or oxidative damage. Moreover, loss of Tdp1 resulted in age-dependent and progressive cerebellar atrophy. Tdp1−/− mice treated with topotecan, a drug that increases levels of Top1–DNA complexes, also demonstrated significant loss of intestinal and hematopoietic progenitor cells. These data indicate that TDP1 is required for neural homeostasis, and reveal a widespread requisite for TDP1 function in response to acutely elevated levels of Top1-associated DNA strand breaks. PMID:17914460

  16. 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

  17. Single nucleotide variations in cultured cancer cells: Effect of mismatch repair.

    PubMed

    Panyutin, Igor G; Panyutin, Irina V; Powell-Castilla, Ian; Felix, Laura; Neumann, Ronald D

    2017-10-01

    We assessed single nucleotide variations (SNVs) between individual cells in two cancer cell lines; DU145, from brain metastasis of prostate tumor with deficient mismatch repair; and HT1080, a fibrosarcoma cell line. Clones of individual cells were isolated, and sequenced using Ion Ampliseq comprehensive cancer panel that covered the exomes of 409 oncogenes and tumor suppressor genes. Five clones of DU145 and four clones of HT1080 cells were analyzed. We found from 7 to 12 unique SNVs between DU145 clones, while HT1080 clones showed no more than one unique SNV. We then sub-cloned individual cells from some of these isolated clones of DU145 and HT1080 cells. The sub-clones were expanded from a single cell to approximately one million cells after about 20 cell divisions. The sub-clones of DU145 cells had from one to four new unique SNVs within the sequenced regions. No unique SNVs were found between sub-clones of HT1080 cells. Our data demonstrate that the extent of genetic variation at the single nucleotide level in cultured cancer cells is significantly affected by the status of the DNA mismatch repair system. Published by Elsevier B.V.

  18. Repair of Single-Strand Deoxyribonucleic Acid Breaks in Ultraviolet Light-Irradiated Haemophilus influenzae

    PubMed Central

    Kantor, George J.; Barnhart, B. J.

    1973-01-01

    The wild-type strain and mutants of Haemophilus influenzae, sensitive or resistant to ultraviolet light (UV) as defined by colony-forming ability, were examined for their ability to perform the incision and rejoining steps of the deoxyribonucleic acid (DNA) dark repair process. Although UV-induced pyrimidine dimers are excised by the wild-type Rd and a resistant mutant BC200, the expected single-strand DNA breaks could not be detected on alkaline sucrose gradients. Repair of the gap resulting from excision must be rapid when experimental conditions described by us are employed. Single-strand DNA breaks were not detected in a UV-irradiated sensitive mutant (BC100) incapable of excising pyrimidine dimers, indicating that this mutant may be defective in a dimer-recognizing endonuclease. No single-strand DNA breaks were detected in a lysogen BC100(HP1c1) irradiated with a UV dose large enough to induce phage development in 80% of the cells. PMID:4540247

  19. Assessment of Kinematics and Electromyography Following Arthroscopic Single-Tendon Rotator Cuff Repair.

    PubMed

    Fritz, Jessica M; Inawat, Ryan R; Slavens, Brooke A; McGuire, John R; Ziegler, Dean W; Tarima, Sergey S; Grindel, Steven I; Harris, Gerald F

    2017-05-01

    The increasing demand for rotator cuff (RC) repair patients to return to work as soon as they are physically able has led to exploration of when this is feasible. Current guidelines from our orthopedic surgery clinic recommend a return to work at 9 weeks postoperation. To more fully define capacity to return to work, the current study was conducted using a unique series of quantitative tools. To date, no study has combined 3-dimensional (3D) motion analysis with electromyography (EMG) assessment during activities of daily living (ADLs), including desk tasks, and commonly prescribed rehabilitation exercise. To apply a quantitative, validated upper extremity model to assess the kinematics and muscle activity of the shoulder following repair of the supraspinatus RC tendon compared to that in healthy shoulders. A prospective, cross-sectional comparison study. All participants were evaluated during a single session at the Medical College of Wisconsin Department of Orthopaedic Surgery's Motion Analysis Laboratory. Ten participants who were 9-12 weeks post-operative repair of a supraspinatus RC tendon tear and 10 participants with healthy shoulders (HS) were evaluated. All participants were evaluated with 3D motion analysis using a validated upper extremity model and synchronized EMG. Data from the 2 groups were compared using multivariate Hotelling T(2) tests with post hoc analyses based on Welch t-tests. Participants' thoracic and thoracohumeral joint kinematics, temporal-spatial parameters, and RC muscle activity were measured by applying a quantitative upper extremity model during 10 ADLs and 3 rehabilitation exercises. These included tasks of hair combing, drinking, writing, computer mouse use, typing, calling, reaching to back pocket, pushing a door open, pulling a door closed, external rotation, internal rotation, and rowing. There were significant differences of the thoracohumeral joint motion in only a few of the tested tasks: comb maximal flexion angle (P = .004

  20. Laparoscopic inguinal hernia repair in the Armed Forces: A 5-year single centre study

    PubMed Central

    Jakhmola, C.K.; Kumar, Ameet

    2015-01-01

    Background Surgery for inguinal hernia continues to evolve. The most recent development in the field of surgery for inguinal hernia is the emergence of laparoscopic inguinal hernia surgery (LIHS) which is challenging the gold standard Lichtenstein's tension free mesh repair. Our centre has the largest series of LIHS from any Armed Forces hospital. The aim of this study was to analyze the short and long term outcomes at our center since its inception. Methods Retrospective review of prospectively maintained data base of 501 LIHS done in 434 patients by a single surgeon between April 2008 and October 2013. Preoperative, intraoperative, postoperative and follow-up data was analyzed with emphasis on the recurrence rates and the incidence of inguinodynia. Results 402 (92.6%) patients had primary hernias and 367 (84.6%) patients had unilateral hernias. Of the 501 repairs, 453 (90.4 %) were done totally extraperitoneal approach and 48 (9.6 %) were done by the transabdominal preperitoneal approach. The mean operative time for unilateral and bilateral repairs was 40.9 ± 11.2 and 76.2 ± 15.0 minutes, respectively. The conversion rate to open surgery was 0.6%. The intraoperative, and early and late postoperative complication rates were 1.7%, 6.2% and 3%, respectively. The incidence of chronic groin pain was 0.7% and the recurrence rate was 1.6%. The median hospital stay was 1 day (1–5 days). Conclusion We, in this series of over 500 repairs have demonstrated that feasibility as well as safety of LIHS at our centre with good short and long term outcomes. PMID:26663957

  1. Ten-Year Single-Center Results of Abdominal Aortic Aneurysm Treatment: Endovascular versus Open Repair.

    PubMed

    Majd, Payman; Ahmad, Wael; Becker, Ingrid; Brunkwall, Jan Sigge

    2017-10-01

    The purpose of the present study was to compare the long-term survival in matched cohorts of patients with infrarenal abdominal aortic aneurysm (AAA) undergoing an elective open repair (OR) or an endovascular aneurysm repair (EVAR). Patients with a primary elective repair of an infrarenal aortic aneurysm between 1998 and 2006 were identified in a retrospective review of our single-center database. EVAR and OR patients were matched with respect to age, gender, renal disease, tobacco use, hypertension, chronic obstructive pulmonary disease, and coronary artery disease. The primary end points were the early mortality and all-cause mortality during follow-up. A total of 465 patients with elective infrarenal aortic aneurysm repair were identified in the database. The EVAR and OR patients were matched according to the above-mentioned characteristics, and finally, 108 patients were included in each group. The early mortality encountered was only one death in the open group (P = 0.316). The Kaplan-Meier survival analysis by the log-rank test showed no difference in cumulative survival between OR group and EVAR group (P = 0.458). Seventeen reinterventions (16.7%) in the EVAR group vs. 7 (6.5%) in the OR group (P = 0.018) were necessary during follow-up. OR and EVAR can be performed safely for elective treatment of AAA. The reintervention rate is, as expected, significantly higher in the EVAR group, but the long-term survival remains equal in both groups. Copyright © 2017 Elsevier Inc. All rights reserved.

  2. Clinical outcomes of single incision laparoscopic surgery and conventional laparoscopic transabdominal preperitoneal inguinal hernia repair

    PubMed Central

    Ece, Ilhan; Yilmaz, Huseyin; Yormaz, Serdar; Sahin, Mustafa

    2017-01-01

    BACKGROUND: Laparoscopic surgery has been a frequently performed method for inguinal hernia repair. Studies have demonstrated that the laparoscopic transabdominal preperitoneal (TAPP) approach is an appropriate choice for inguinal hernia repair. Single-incision laparoscopic surgery (SILS) was developed to improve the cosmetic effects of conventional laparoscopy. The aim of this study was to evaluate the safety and feasibility of SILS-TAPP compared with TAPP technique. MATERIALS AND METHODS: A total of 148 patients who underwent TAPP or SILS-TAPP in our surgery clinic between December 2012 and January 2015 were enrolled. Data including patient demographics, hernia characteristics, operative time, intraoperative and postoperative complications, length of hospital stay and recurrence rate were retrospectively collected. RESULTS: In total, 60 SILS-TAPP and 88 TAPP procedures were performed in the study period. The two groups were similar in terms of gender, type of hernia, and American Society of Anesthesiologists (ASA) classification score. The patients in the SILS-TAPP group were younger when compared the TAPP group. Port site hernia (PSH) rate was significantly high in the SILS-TAPP group, and all PSHs were recorded in patients with severe comorbidities. The mean operative time has no significant difference in two groups. All SILS procedures were completed successfully without conversion to conventional laparoscopy or open repair. No intraoperative complication was recorded. There was no recurrence during the mean follow-up period of 15.2 ± 3.8 months. CONCLUSION: SILS TAPP for inguinal hernia repair seems to be a feasible, safe method, and is comparable with TAPP technique. However, randomized trials are required to evaluate long-term clinical outcomes. PMID:27251835

  3. Transcript-RNA-templated DNA recombination and repair.

    PubMed

    Keskin, Havva; Shen, Ying; Huang, Fei; Patel, Mikir; Yang, Taehwan; Ashley, Katie; Mazin, Alexander V; Storici, Francesca

    2014-11-20

    Homologous recombination is a molecular process that has multiple important roles in DNA metabolism, both for DNA repair and genetic variation in all forms of life. Generally, homologous recombination involves the exchange of genetic information between two identical or nearly identical DNA molecules; however, homologous recombination can also occur between RNA molecules, as shown for RNA viruses. Previous research showed that synthetic RNA oligonucleotides can act as templates for DNA double-strand break (DSB) repair in yeast and human cells, and artificial long RNA templates injected in ciliate cells can guide genomic rearrangements. Here we report that endogenous transcript RNA mediates homologous recombination with chromosomal DNA in yeast Saccharomyces cerevisiae. We developed a system to detect the events of homologous recombination initiated by transcript RNA following the repair of a chromosomal DSB occurring either in a homologous but remote locus, or in the same transcript-generating locus in reverse-transcription-defective yeast strains. We found that RNA-DNA recombination is blocked by ribonucleases H1 and H2. In the presence of H-type ribonucleases, DSB repair proceeds through a complementary DNA intermediate, whereas in their absence, it proceeds directly through RNA. The proximity of the transcript to its chromosomal DNA partner in the same locus facilitates Rad52-driven homologous recombination during DSB repair. We demonstrate that yeast and human Rad52 proteins efficiently catalyse annealing of RNA to a DSB-like DNA end in vitro. Our results reveal a novel mechanism of homologous recombination and DNA repair in which transcript RNA is used as a template for DSB repair. Thus, considering the abundance of RNA transcripts in cells, RNA may have a marked impact on genomic stability and plasticity.

  4. A genomics-based screen for yeast mutants with an altered recombination/end-joining repair ratio.

    PubMed Central

    Wilson, Thomas E

    2002-01-01

    We recently described a yeast assay suitable for genetic screening in which simple religation nonhomologous end-joining (NHEJ) and single-strand annealing (SSA) compete for repair of an I-SceI-created double-strand break. Here, the required allele has been introduced into an array of 4781 MATa deletion mutants and each strain screened individually. Two mutants (rad52 and srs2) showed a clear increase in the NHEJ/SSA ratio due to preferential impairment of SSA, but no mutant increased the absolute frequency of NHEJ significantly above the wild-type level. Seven mutants showed a decreased NHEJ/SSA ratio due to frank loss of NHEJ, which corresponded to all known structural/catalytic NHEJ components (yku70, yku80, dnl4, lif1, rad50, mre11, and xrs2); no new mutants in this category were identified. A clearly separable and surprisingly large set of 16 other mutants showed partial defects in NHEJ. Further examination of these revealed that NEJ1 can entirely account for the mating-type regulation of NHEJ, but that this regulatory role was distinct from the postdiauxic/stationary-phase induction of NHEJ that was deficient in other mutants (especially doa1, fyv6, and mck1). These results are discussed in the context of the minimal set of required proteins and regulatory inputs for NHEJ. PMID:12399380

  5. 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

  6. Single-Institution Financial Analysis of Biologic Versus Synthetic Mesh Hernia Repair: A Retrospective Analysis of Patients Readmitted for Hernia Repair.

    PubMed

    Otake, Leo R; Satterwhite, Thomas; Echo, Anthony; Chiou, Grace; Lee, Gordon K

    2013-07-11

    The advent and proliferation of commercially available biologic mesh material has expanded the repertoire of hernia repair materials available to the surgeon. Given the higher initial cost of these mesh materials relative to synthetic materials such as polypropylene, there has been debate regarding the purported benefit of the use of biologic mesh. This study is a single-institution review of complex hernia repairs using both biologic and synthetic mesh materials. The patients included in the analyses were admitted to the institution at least twice for management of hernia; this permitted specific evaluation of a given diagnosis, hernia, in the same patient, but at different points in time. In a subset of patients, hernia repair was performed upon the second admission with conversion from biologic or synthetic mesh, which had been placed at the initial repair. The objective of this study was to evaluate the financial implications of mesh choice. Specific parameters reviewed included type of mesh used, total costs of hospitalization, direct cost associated with the hernia repair, total collections, and percentage of collections relative to total charges. Through such analysis, our aim was to determine whether there were any variances in revenue and costs associated with the application of either mesh material or the associated clinical scenarios.

  7. 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

  8. Functional Validation of Rare Human Genetic Variants Involved in Homologous Recombination Using Saccharomyces cerevisiae.

    PubMed

    Lee, Min-Soo; Yu, Mi; Kim, Kyoung-Yeon; Park, Geun-Hee; Kwack, KyuBum; Kim, Keun P

    2015-01-01

    Systems for the repair of DNA double-strand breaks (DSBs) are necessary to maintain genome integrity and normal functionality of cells in all organisms. Homologous recombination (HR) plays an important role in repairing accidental and programmed DSBs in mitotic and meiotic cells, respectively. Failure to repair these DSBs causes genome instability and can induce tumorigenesis. Rad51 and Rad52 are two key proteins in homologous pairing and strand exchange during DSB-induced HR; both are highly conserved in eukaryotes. In this study, we analyzed pathogenic single nucleotide polymorphisms (SNPs) in human RAD51 and RAD52 using the Polymorphism Phenotyping (PolyPhen) and Sorting Intolerant from Tolerant (SIFT) algorithms and observed the effect of mutations in highly conserved domains of RAD51 and RAD52 on DNA damage repair in a Saccharomyces cerevisiae-based system. We identified a number of rad51 and rad52 alleles that exhibited severe DNA repair defects. The functionally inactive SNPs were located near ATPase active site of Rad51 and the DNA binding domain of Rad52. The rad51-F317I, rad52-R52W, and rad52-G107C mutations conferred hypersensitivity to methyl methane sulfonate (MMS)-induced DNA damage and were defective in HR-mediated DSB repair. Our study provides a new approach for detecting functional and loss-of-function genetic polymorphisms and for identifying causal variants in human DNA repair genes that contribute to the initiation or progression of cancer.

  9. Functional Validation of Rare Human Genetic Variants Involved in Homologous Recombination Using Saccharomyces cerevisiae

    PubMed Central

    Lee, Min-Soo; Yu, Mi; Kim, Kyoung-Yeon; Park, Geun-Hee; Kwack, KyuBum; Kim, Keun P.

    2015-01-01

    Systems for the repair of DNA double-strand breaks (DSBs) are necessary to maintain genome integrity and normal functionality of cells in all organisms. Homologous recombination (HR) plays an important role in repairing accidental and programmed DSBs in mitotic and meiotic cells, respectively. Failure to repair these DSBs causes genome instability and can induce tumorigenesis. Rad51 and Rad52 are two key proteins in homologous pairing and strand exchange during DSB-induced HR; both are highly conserved in eukaryotes. In this study, we analyzed pathogenic single nucleotide polymorphisms (SNPs) in human RAD51 and RAD52 using the Polymorphism Phenotyping (PolyPhen) and Sorting Intolerant from Tolerant (SIFT) algorithms and observed the effect of mutations in highly conserved domains of RAD51 and RAD52 on DNA damage repair in a Saccharomyces cerevisiae-based system. We identified a number of rad51 and rad52 alleles that exhibited severe DNA repair defects. The functionally inactive SNPs were located near ATPase active site of Rad51 and the DNA binding domain of Rad52. The rad51-F317I, rad52-R52W, and rad52-G107C mutations conferred hypersensitivity to methyl methane sulfonate (MMS)-induced DNA damage and were defective in HR-mediated DSB repair. Our study provides a new approach for detecting functional and loss-of-function genetic polymorphisms and for identifying causal variants in human DNA repair genes that contribute to the initiation or progression of cancer. PMID:25938495

  10. Homologous recombinational repair factors are recruited and loaded onto the viral DNA genome in Epstein-Barr virus replication compartments.

    PubMed

    Kudoh, Ayumi; Iwahori, Satoko; Sato, Yoshitaka; Nakayama, Sanae; Isomura, Hiroki; Murata, Takayuki; Tsurumi, Tatsuya

    2009-07-01

    Homologous recombination is an important biological process that facilitates genome rearrangement and repair of DNA double-strand breaks (DSBs). The induction of Epstein-Barr virus (EBV) lytic replication induces ataxia telangiectasia-mutated (ATM)-dependent DNA damage checkpoint signaling, leading to the clustering of phosphorylated ATM and Mre11/Rad50/Nbs1 (MRN) complexes to sites of viral genome synthesis in nuclei. Here we report that homologous recombinational repair (HRR) factors such as replication protein A (RPA), Rad51, and Rad52 as well as MRN complexes are recruited and loaded onto the newly synthesized viral genome in replication compartments. The 32-kDa subunit of RPA is extensively phosphorylated at sites in accordance with those with ATM. The hyperphosphorylation of RPA32 causes a change in RPA conformation, resulting in a switch from the catalysis of DNA replication to the participation in DNA repair. The levels of Rad51 and phosphorylated RPA were found to increase with the progression of viral productive replication, while that of Rad52 proved constant. Furthermore, biochemical fractionation revealed increases in levels of DNA-bound forms of these HRRs. Bromodeoxyuridine-labeled chromatin immunoprecipitation and PCR analyses confirmed the loading of RPA, Rad 51, Rad52, and Mre11 onto newly synthesized viral DNA, and terminal deoxynucleotidyltransferase-mediated dUTP nick end labeling analysis demonstrated DSBs in the EBV replication compartments. HRR factors might be recruited to repair DSBs on the viral genome in viral replication compartments. RNA interference knockdown of RPA32 and Rad51 prevented viral DNA synthesis remarkably, suggesting that homologous recombination and/or repair of viral DNA genome might occur, coupled with DNA replication to facilitate viral genome synthesis.

  11. In vivo single-molecule imaging of bacterial DNA replication, transcription, and repair.

    PubMed

    Stracy, Mathew; Uphoff, Stephan; Garza de Leon, Federico; Kapanidis, Achillefs N

    2014-10-01

    In vivo single-molecule experiments offer new perspectives on the behaviour of DNA binding proteins, from the molecular level to the length scale of whole bacterial cells. With technological advances in instrumentation and data analysis, fluorescence microscopy can detect single molecules in live cells, opening the doors to directly follow individual proteins binding to DNA in real time. In this review, we describe key technical considerations for implementing in vivo single-molecule fluorescence microscopy. We discuss how single-molecule tracking and quantitative super-resolution microscopy can be adapted to extract DNA binding kinetics, spatial distributions, and copy numbers of proteins, as well as stoichiometries of protein complexes. We highlight experiments which have exploited these techniques to answer important questions in the field of bacterial gene regulation and transcription, as well as chromosome replication, organisation and repair. Together, these studies demonstrate how single-molecule imaging is transforming our understanding of DNA-binding proteins in cells. Copyright © 2014 Federation of European Biochemical Societies. Published by Elsevier B.V. All rights reserved.

  12. Cost disparity between open repair and endovascular aneurysm repair for abdominal aortic aneurysm: a single-institute experience in Japan.

    PubMed

    Morimae, Hirofumi; Maekawa, Takashi; Tamai, Hiroaki; Takahashi, Noriko; Ihara, Tsutomu; Hori, Akihiko; Narita, Hiroshi; Banno, Hiroshi; Kobayashi, Masayoshi; Yamamoto, Kiyohito; Komori, Kimihiro

    2012-01-01

    We conducted this study to compare the cost of open surgical repair (OR) with that of endovascular aneurysm repair (EVAR) of an abdominal aortic aneurysm (AAA). Between January 2007 and November 2008, 70 patients underwent open repair and 57 patients underwent EVAR. We evaluated the total cost, including that of the Diagnosis Procedure Combination (DPC), that of the surgical procedure, that of materials such as grafts and guide wires, and that of the anesthesia. The mean costs for OR versus EVAR were as follows: DPC, ¥632,370 versus ¥490,050, respectively, which was significant; anesthesia, ¥123,540 versus ¥86,220, respectively (P < 0.05); and materials, ¥257,770 versus ¥2,113,280, respectively (P < 0.05). Thus, the mean total cost was ¥1,825,830 versus ¥3,159,270 for open repair and EVAR, respectively (P < 0.05). New technologies should not only be clinically effective, but also cost effective. EVAR is less invasive clinically, but the cost of endovascular prostheses and other materials remains high.

  13. 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.

  14. Single-Incision Laparoscopic Intraperitoneal Onlay Mesh Repair for the Treatment of Multiple Recurrent Inguinal Hernias

    PubMed Central

    Tran, Kim; Zajkowska, Marta; Lam, Vincent; Hawthorne, Wayne

    2014-01-01

    Introduction: Despite an exponential rise in laparoscopic surgery for inguinal herniorrhaphy, overall recurrence rates have remained unchanged. Therefore, an increasing number of patients present with recurrent hernias after having failed anterior and laparoscopic repairs. This study reports our experience with single-incision laparoscopic (SIL) intraperitoneal onlay mesh (IPOM) repair for these hernias. Materials and methods: All patients referred with multiply recurrent inguinal hernias underwent SIL-IPOM from November 1 2009 to October 30 2013. A 2.5-cm infraumbilical incision was made and a SIL surgical port was placed intraperitoneally. Modified dissection techniques, namely, “chopsticks” and “inline” dissection, 5.5 mm/52 cm/30° angled laparoscope and conventional straight dissecting instruments were used. The peritoneum was incised above the symphysis pubis and dissection continued laterally and proximally raising an inferior flap, below a previous extraperitoneal mesh, while reducing any direct/indirect/femoral/cord lipoma before placement of antiadhesive mesh that was fixed into the pubic ramus as well as superiorly with nonabsorbable tacks before fixing its inferior border with fibrin sealant. The inferior peritoneal flap was then tacked back onto the mesh. Results: There were 9 male patients who underwent SIL-IPOM. Mean age was 55 years old and mean body mass index was 26.8 kg/m2. Mean mesh size was 275 cm2. Mean operation time was 125 minutes with hospital stay of 1 day and umbilical scar length of 21 mm at 4 weeks' follow-up. There were no intraoperative/postoperative complications, port-site hernias, chronic groin pain, or recurrence with mean follow-up of 20 months. Conclusions: Multiply recurrent inguinal hernias after failed conventional anterior and laparoscopic repairs can be treated safely and efficiently with SIL-IPOM. PMID:25392643

  15. Single-Molecule Imaging Reveals How Mre11-Rad50-Nbs1 Initiates DNA Break Repair.

    PubMed

    Myler, Logan R; Gallardo, Ignacio F; Soniat, Michael M; Deshpande, Rajashree A; Gonzalez, Xenia B; Kim, Yoori; Paull, Tanya T; Finkelstein, Ilya J

    2017-09-07

    DNA double-strand break (DSB) repair is essential for maintaining our genomes. Mre11-Rad50-Nbs1 (MRN) and Ku70-Ku80 (Ku) direct distinct DSB repair pathways, but the interplay between these complexes at a DSB remains unclear. Here, we use high-throughput single-molecule microscopy to show that MRN searches for free DNA ends by one-dimensional facilitated diffusion, even on nucleosome-coated DNA. Rad50 binds homoduplex DNA and promotes facilitated diffusion, whereas Mre11 is required for DNA end recognition and nuclease activities. MRN gains access to occluded DNA ends by removing Ku or other DNA adducts via an Mre11-dependent nucleolytic reaction. Next, MRN loads exonuclease 1 (Exo1) onto the free DNA ends to initiate DNA resection. In the presence of replication protein A (RPA), MRN acts as a processivity factor for Exo1, retaining the exonuclease on DNA for long-range resection. Our results provide a mechanism for how MRN promotes homologous recombination on nucleosome-coated DNA. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Synergistic decrease of DNA single-strand break repair rates in mouse neural cells lacking both Tdp1 and aprataxin

    PubMed Central

    El-Khamisy, Sherif F.; Katyal, Sachin; Patel, Poorvi; Ju, Limei; McKinnon, Peter J.; Caldecott, Keith W.

    2009-01-01

    Ataxia oculomotor apraxia-1 (AOA1) is an autosomal recessive neurodegenerative disease that results from mutations of aprataxin (APTX). APTX associates with the DNA single- and double-strand break repair machinery and is able to remove AMP from 5′-termini at DNA strand breaks in vitro. However, attempts to establish a DNA strand break repair defect in APTX-defective cells have proved conflicting and unclear. We reasoned that this may reflect that DNA strand breaks with 5′-AMP represent only a minor subset of breaks induced in cells, and/or the availability of alternative mechanisms for removing AMP from 5′-termini. Here, we have attempted to increase the dependency of chromosomal single- and double-strand break repair on aprataxin activity by slowing the rate of repair of 3′-termini in aprataxin-defective neural cells, thereby increasing the likelihood that the 5′-termini at such breaks become adenylated and/or block alternative repair mechanisms. To do this, we generated a mouse model in which APTX is deleted together with tyrosyl DNA phosphodiesterase (TDP1), an enzyme that repairs 3′-termini at a subset of single-strand breaks (SSBs), including those with 3′-topoisomerase-1 (Top1) peptide. Notably, the global rate of repair of oxidative and alkylation-induced SSBs was significantly slower in Tdp1−/−/Aptx−/− double knockout quiescent mouse astrocytes compared with Tdp1−/− or Aptx−/− single knockouts. In contrast, camptothecin-induced Top1-SSBs accumulated to similar levels in Tdp1−/− and Tdp1−/−/Aptx−/− double knockout astrocytes. Finally, we failed to identify a measurable defect in double-strand break repair in Tdp1−/−, Aptx−/− or Tdp1−/−/Aptx−/− astrocytes. These data provide direct evidence for a requirement for aprataxin during chromosomal single-strand break repair in primary neural cells lacking Tdp1. PMID:19303373

  17. First successful replantation of face and scalp with single-artery repair: model for face and scalp transplantation.

    PubMed

    Wilhelmi, Bradon J; Kang, Robert H; Movassaghi, Kiumars; Ganchi, Parham A; Lee, W P Andrew

    2003-05-01

    Successful replantation of the scalp with microanastomosis of a single artery and vein has been reported to produce reliable results. In fact, there have been several reports of scalp replantations based on one-artery and vein repair. There has been a face and scalp replantation reported in the literature, but this was as two separate parts and was based on several arterial and venous repairs. The authors performed the first successful replantation of a face and scalp with repair of a single artery and, of course, two veins. A 21-year-old man presented after his face and scalp were completely severed. The patient's long hair was caught in a conveyor belt at work. The face and scalp underwent replantation, with repair of the right superficial temporal artery with an interposition vein graft. A multiteam approach allowed for minimization of overall ischemic time and simultaneous preparation of the vessels on the patient and amputated part as well as vein graft harvest from the arm. Also critical to the success of the procedure, the small portions of the vessels of the amputated part were sent for frozen section to differentiate artery from vein. Initially, only the right superficial temporal vein was repaired. One week after replantation, the patient returned for treatment of venous congestion of an area to the opposite side of the forehead partial transection, with repair of the left superficial temporal vein, also. This saved the entire part that underwent replantation, and the entire part survived. The face and scalp can undergo replantation based on single-artery repair.

  18. Single nucleotide polymorphisms of nucleotide excision repair and homologous recombination repair pathways and their role in the risk of osteosarcoma

    PubMed Central

    Jin, Guojun; Wang, Min; Chen, Weida; Shi, Wei; Yin, Jiapeng; Gang, Wang

    2015-01-01

    Objective: To evaluate the influence of polymorphisms in nucleotide excision repair (NER) and homologous recombination repair (HRR) pathways on the development of osteosarcoma patients. Methods: Genotypes of ERCC1 rs11615 and rs3212986, ERCC2 rs1799793 and rs13181, NBN rs709816 and rs1805794, RAD51 rs1801320, rs1801321 and rs12593359, and XRCC3 rs861539 were conducted by Polymerase Chain Reaction Restriction Fragment Length Polymorphism (PCR-RFLP) assay. Results: Total 148 osteosarcoma patients and 296 control subjects were collected from Taizhou First People’s Hospital. Conditional logistic regression analyses found that individuals carrying with GA+AA genotype of ERCC2 rs1799793 and GC+CC genotype of NBN rs1805794 were significantly associated with increased risk of osteosarcoma, and the ORs(95%CI) were 1.58(1.03-2.41) and 2.66(1.73-4.08), respectively. We found that GA+AA genotype of ERCC2 rs1799793 or GC+CC genotype of NBN rs1805794 were associated with an increased risk of osteosarcoma in females, with ORs(95%CI) of 2.42(1.20-4.87) and 2.01(1.07-4.23), respectively. Conclusion: Our results suggest that ERCC2 rs1799793 and NBN rs1805794 polymorphisms were associated with an increased risk for osteosarcoma, which suggests that NER and HRR pathways modulate the risk of developing osteosarcoma. PMID:26101473

  19. Perioperative Outcomes, Complications, and Efficacy of Robotic-Assisted Prolapse Repair: A Single Institution Study of 196 Patients.

    PubMed

    Gupta, Priyanka; Ehlert, Michael; Bartley, Jamie; Gilleran, Jason; Killinger, Kim A; Boura, Judith A; Nagaraju, Pradeep; Fischer, Melissa

    2017-09-15

    Abdominal pelvic organ prolapse repair is efficacious for uterovaginal and apical prolapse. We describe the safety and efficacy of robotic prolapse repair in a large teaching institution. Consecutive robotic-assisted prolapse repairs at a single institution between 2006 and 2014 were retrospectively reviewed for patient characteristics, operative information, and outcomes. A total of 196 women (mean age, 61 ± 9 years) underwent robotic prolapse repair (189 sacrocolpopexy, 6 sacrohysteropexy, 1 enterocele repair). Concomitant procedures included hysterectomy (88), midurethral sling (84), and/or Burch colposuspension (7). Mean odds ratio time was 242 ± 69.9 minutes, and median length of stay was 1 day. Intraoperative complications were as follows: cystotomy (4), vaginotomy (4), conversion to open (2), bowel injury/aborted (1), adhesions/aborted (1), and ureteral injury (1). Women with complications had greater blood loss than those without complications (P = 0.0015). Immediate (<30 days) postoperative complications were rare: port-site hernia (2), discitis (1), ileus (1), and ulnar neuropraxia (3). At median follow-up of 9 months (range, 0-85 months), 14 women had recurrent grade 3 prolapse, and 4 had grade 2 apical prolapse. Nine of 14 women had additional prolapse repair at a mean of 9.5 ± 6.3 months. Vaginal mesh exposure was detected in 12 (6.3%) of 192 women. There were 6 procedures for mesh exposure and 2 procedures for exposed sutures. One mesh erosion into the bladder required open excision. In this large series of robotic prolapse repair, complications are infrequent. Short-term apical outcomes are excellent. Few women required additional compartment repairs within 1 year with 6% rate of mesh exposure.

  20. Ambulatory open Bankart repair under a single general anesthesia: a prospective study of the immediate outcome.

    PubMed

    Molina, Véronique; Gagey, Olivier; Langloÿs, Joel

    2006-01-01

    The interscalenic block technique is widely used for ambulatory shoulder surgery despite a substantial number of failures and adverse effects. We prospectively evaluated satisfaction in 40 consecutive patients who underwent open Bankart repair under a single general anesthesic performed in an ambulatory care unit. The mean age of the patients was 23 years. There were 29 men and 11 women. Patients were evaluated postoperatively with a visual analog scale of pain (in the recovery room, at the time of discharge, and the day after and 1 week after surgery) via a home assessment questionnaire that included the following: effectiveness of oral pain medication, ability to perform activities of daily life, and overall satisfaction. One patient failed to be discharged because of a feeling of faintness not related to pain. None of the 39 patients would have preferred an overnight hospital stay. This study confirms that the open Bankart procedure is feasible as a same-day technique and indicates that a single anesthesic with proper management of analgesia is a reliable technique for major shoulder surgery in an ambulatory care unit.

  1. Prospective study of single-stage repair of contaminated hernias using a biologic porcine tissue matrix: the RICH Study.

    PubMed

    Itani, Kamal M F; Rosen, Michael; Vargo, Daniel; Awad, Samir S; Denoto, George; Butler, Charles E

    2012-09-01

    In the presence of contamination, the repair of a ventral incisional hernia (VIH) is challenging. The presence of comorbidities poses an additional risk for postoperative wound events and hernia recurrence. To date, very few studies describe the outcomes of VIH repair in this high-risk population. A prospective, multicenter, single-arm, the Repair of Infected or Contaminated Hernias study was performed to study the clinical outcomes of open VIH repair of contaminated abdominal defects with a non-cross-linked, porcine, acellular dermal matrix, Strattice. Of 85 patients who consented to participate, 80 underwent open VIH repair with Strattice. Hernia defects were 'clean-contaminated' (n = 39), 'contaminated' (n = 39), or 'dirty' (n = 2), and the defects were classified as grade 3 (n = 60) or grade 4 (n = 20). The midline was restored, and primary closure was achieved in 64 patients; the defect was bridged in 16 patients. At 24 months, 53 patients (66%) experienced 95 wound events. There were 28 unique, infection-related events in 24 patients. Twenty-two patients experienced seromas, all but 5 of which were transient and required no intervention. No unanticipated adverse events occurred, and no tissue matrix required complete excision. There were 22 hernia (28%) recurrences by month 24. There was no correlation between infection-related events and hernia recurrence. The use of the intact, non-cross-linked, porcine, acellular dermal matrix, Strattice, in the repair of contaminated VIH in high-risk patients allowed for successful, single-stage reconstruction in >70% of patients followed for 24 months after repair. Published by Mosby, Inc.

  2. Specific targeted gene repair using single-stranded DNA oligonucleotides at an endogenous locus in mammalian cells uses homologous recombination.

    PubMed

    McLachlan, Jennifer; Fernandez, Serena; Helleday, Thomas; Bryant, Helen E

    2009-12-03

    The feasibility of introducing point mutations in vivo using single-stranded DNA oligonucleotides (ssON) has been demonstrated but the efficiency and mechanism remain elusive and potential side effects have not been fully evaluated. Understanding the mechanism behind this potential therapy may help its development. Here, we demonstrate the specific repair of an endogenous non-functional hprt gene by a ssON in mammalian cells, and show that the frequency of such an event is enhanced when cells are in S-phase of the cell cycle. A potential barrier in using ssONs as gene therapy could be non-targeted mutations or gene rearrangements triggered by the ssON. Both the non-specific mutation frequencies and the frequency of gene rearrangements were largely unaffected by ssONs. Furthermore, we find that the introduction of a mutation causing the loss of a functional endogenous hprt gene by a ssON occurred at a similarly low but statistically significant frequency in wild type cells and in cells deficient in single strand break repair, nucleotide excision repair and mismatch repair. However, this mutation was not induced in XRCC3 mutant cells deficient in homologous recombination. Thus, our data suggest ssON-mediated targeted gene repair is more efficient in S-phase and involves homologous recombination.

  3. Thoracoscopic Versus Open Congenital Diaphragmatic Hernia Repair: Single Tertiary Center Review.

    PubMed

    Tyson, Anna F; Sola, Richard; Arnold, Michael R; Cosper, Graham H; Schulman, Andrew M

    2017-10-04

    Congenital diaphragmatic hernia (CDH) can be repaired open or through thoracoscopy. Thoracoscopic CDH repair could improve cosmesis and avoid the complications of laparotomy, but may have higher recurrence rates. The purpose of this study was to examine the outcomes of thoracoscopic versus open CDH repair, with regard to recurrence, perioperative parameters, and postoperative complications. We performed a retrospective review of open versus thoracoscopic CDH repairs over an 8.5-year period. The primary outcome was hernia recurrence. Secondary outcomes included intraoperative partial pressure of carbon dioxide (pCO2) levels, length of stay, and postoperative complications. All statistical analyses were performed using standard statistical methods. A total of 54 infants underwent CDH repair during the study period, of whom 25 underwent successful thoracoscopic repair. Two patients who had undergone open repair developed recurrent diaphragmatic hernias (recurrence rate 3.7%). Operative time and intraoperative pCO2 levels did not differ between groups. Length of stay was shorter in the thoracoscopic cohort. Four patients in the open cohort developed ventral hernias and five developed bowel obstructions during follow-up. No long-term complications were identified in the thoracoscopic cohort. The median follow-up was 27 months. In our experience, thoracoscopic CDH repair was performed safely and with similar outcomes compared to open repair. In addition to improved cosmesis, thoracoscopic repair may avoid some of the long-term complications of laparotomy. In our series, none of the thoracoscopic CDH repairs recurred. We conclude that thoracoscopic CDH repair is a safe and appropriate technique for select neonates.

  4. On adhesive properties of perlite and sewage sludge ash with epoxy resin bonded single-strap repairs

    NASA Astrophysics Data System (ADS)

    Bulut, Mehmet; Erkliğ, Ahmet; Furkan Doğan, Nurettin

    2017-08-01

    In this study, the tensile properties of epoxy adhesive with the inclusion of micro-scale perlite and sewage sludge ash (SSA) particles were investigated for glass-epoxy laminates adhesively bonded single-strap repairs. Particle fillers were incorporated in the epoxy resin as an additive material at different ratios by weight, namely, 5, 10, 15 wt% for perlite; 5, 10, 15 and 20 wt% for SSA as well as unfilled composites. Composite samples were weakened by opening a circular cutout at the center of them, and then repaired by the circular patches produced from the same material. The repairing performances of samples were explored for two different patch ratios (D/d  =  2 and 3). Results indicated that the inclusion of perlite and SSA particles in the epoxy adhesive contributed to a significant increase in load carrying capacity at a weight content of 10 wt%.

  5. Detection of DNA single-strand breaks during the repair of UV damage in xeroderma pigmentosum cells

    SciTech Connect

    Fornace, A.J. Jr.; Seres, D.S.

    1983-01-01

    In this investigation, xeroderma pigmentosum (XP) fibroblasts, XP12BE, were uv-irradiated and then incubated with cytosine arabinoside and hydroxyurea for 4 hr to inhibit the polymerase step of DNA excision repair. By alkaline elution, DNA single-strand breaks (SSB) were detected in XP cells with this regimen with an efficiency of 0.1-0.2 SSB per 10/sup 9/ daltons of DNA per J m/sup -2/. There was an approximately linear relation between the SSB frequency and uv dose over a range of 0.2 to 25 J m/sup -2/. This effect was approximately two orders of magnitude greater in excision-proficient normal human fibroblasts than in XP cells. These results support the conclusion that a low residual level of DNA excision repair occurs in XP group A cells and that the SSB generated during this repair can be accumulated with this polymerase inhibitor.

  6. 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.

  7. Acute distal biceps ruptures: single incision repair by use of suture anchors.

    PubMed

    Maciel, Rafael Almeida; Costa, Priscilla Silva; Figueiredo, Eduardo Antônio; Belangero, Paulo Santoro; Pochini, Alberto de Castro; Ejnisman, Benno

    2017-01-01

    Clinical and functional assessment of the surgical treatment for acute injury of the distal insertion of the biceps brachial performed with a surgical technique using a single incision in proximal forearm and fixation with suture anchors in the radial tuberosity. This study reviewed the medical records of patients who underwent surgical treatment of distal biceps injury during the period between January 2008 and July 2014. In a mean follow-up of 12 months, 22 patients with complete and acute injury, diagnosed through physical examination and imaging studies, were functionally assessed in the postoperative period regarding the range of motion (degrees of flexion-extension and pronation-supination), the presence of pain (VAS), the Andrews Carson-score, and the Mayo Elbow Performance Score (MEPS). During the postoperative follow-up assessment, no patient reported pain by VAS scale; all were satisfied with the esthetic appearance of the surgery. The range of articular movement remained unchanged at 95.4% of patients, with the loss of 8° of supination in one patient. No changes in muscle strength were observed. The results of the Andrews-Carson score were good in 4.6% and excellent in 95.4% of cases; the MEPS presented 100% of excellent results. The rate of complications was 27.2%, similar to the literature. Surgical repair of acute injury of the distal biceps trough a single incision in the proximal forearm and fixation with two suture anchors in the radial tuberosity is an effective and safe therapeutic option, allowing early motion and good functional results.

  8. Relative rates of repair of single-strand breaks and postirradiation DNA degradation in normal and induced cells of Escherichia coli.

    PubMed Central

    Pollard, E C; Fugate, J K

    1978-01-01

    Labeled DNA from irradiated Excherichia coli cells has been studied on an alkaline sucrose gradient without acid precipitation of the DNA. This enables the observation of both DNA repair and DNA degradation. The use of a predose of ultraviolet light (UV) causes induction of an inhibitor of postirradiation DNA degradation in lex+ strains. The effect of this induction on both the repair of single-strand breaks and DNA degradation has been followed in strains WU3610 (uvr+) and WU3610-89 (uvr-). The repair process is more rapid than the degradation, and when degradation is inhibited more repair is apparent. Cells that are lex- (Bs-1 and AB2474) cannot be induced for inhibition of degradation. Nevertheless, by observation at short times repair can be seen clearly. This repaired DNA is degraded, suggesting that the signal for DNA degradation is not a single-strand break. PMID:365253

  9. Regulation of recombination at yeast nuclear pores controls repair and triplet repeat stability.

    PubMed

    Su, Xiaofeng A; Dion, Vincent; Gasser, Susan M; Freudenreich, Catherine H

    2015-05-15

    Secondary structure-forming DNA sequences such as CAG repeats interfere with replication and repair, provoking fork stalling, chromosome fragility, and recombination. In budding yeast, we found that expanded CAG repeats are more likely than unexpanded repeats to localize to the nuclear periphery. This positioning is transient, occurs in late S phase, requires replication, and is associated with decreased subnuclear mobility of the locus. In contrast to persistent double-stranded breaks, expanded CAG repeats at the nuclear envelope associate with pores but not with the inner nuclear membrane protein Mps3. Relocation requires Nup84 and the Slx5/8 SUMO-dependent ubiquitin ligase but not Rad51, Mec1, or Tel1. Importantly, the presence of the Nup84 pore subcomplex and Slx5/8 suppresses CAG repeat fragility and instability. Repeat instability in nup84, slx5, or slx8 mutant cells arises through aberrant homologous recombination and is distinct from instability arising from the loss of ligase 4-dependent end-joining. Genetic and physical analysis of Rad52 sumoylation and binding at the CAG tract suggests that Slx5/8 targets sumoylated Rad52 for degradation at the pore to facilitate recovery from acute replication stress by promoting replication fork restart. We thereby confirmed that the relocation of damage to nuclear pores plays an important role in a naturally occurring repair process.

  10. 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

  11. Functional Outcomes After Double-Row Versus Single-Row Rotator Cuff Repair: A Prospective Randomized Trial.

    PubMed

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

    2016-10-01

    The functional benefits of double-row (DR) versus single-row (SR) rotator cuff repair are not clearly established. To examine the effect of DR versus SR rotator cuff repair on functional outcomes and strength recovery in patients with full-thickness tears. Randomized controlled trial; Level of evidence, 2. 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. 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 improved strength in empty-can (54%), full-can (66

  12. Defective DNA Ligation during Short-Patch Single-Strand Break Repair in Ataxia Oculomotor Apraxia 1 ▿

    PubMed Central

    Reynolds, John J.; El-Khamisy, Sherif F.; Katyal, Sachin; Clements, Paula; McKinnon, Peter J.; Caldecott, Keith W.

    2009-01-01

    Ataxia oculomotor apraxia 1 (AOA1) results from mutations in aprataxin, a component of DNA strand break repair that removes AMP from 5′ termini. Despite this, global rates of chromosomal strand break repair are normal in a variety of AOA1 and other aprataxin-defective cells. Here we show that short-patch single-strand break repair (SSBR) in AOA1 cell extracts bypasses the point of aprataxin action at oxidative breaks and stalls at the final step of DNA ligation, resulting in the accumulation of adenylated DNA nicks. Strikingly, this defect results from insufficient levels of nonadenylated DNA ligase, and short-patch SSBR can be restored in AOA1 extracts, independently of aprataxin, by the addition of recombinant DNA ligase. Since adenylated nicks are substrates for long-patch SSBR, we reasoned that this pathway might in part explain the apparent absence of a chromosomal SSBR defect in aprataxin-defective cells. Indeed, whereas chemical inhibition of long-patch repair did not affect SSBR rates in wild-type mouse neural astrocytes, it uncovered a significant defect in Aptx−/− neural astrocytes. These data demonstrate that aprataxin participates in chromosomal SSBR in vivo and suggest that short-patch SSBR arrests in AOA1 because of insufficient nonadenylated DNA ligase. PMID:19103743

  13. Correlation Between American Shoulder and Elbow Surgeons and Single Assessment Numerical Evaluation Score After Rotator Cuff or SLAP Repair.

    PubMed

    Cunningham, Gregory; Lädermann, Alexandre; Denard, Patrick J; Kherad, Omar; Burkhart, Stephen S

    2015-09-01

    To compare the American Shoulder and Elbow Surgeons (ASES) and the Single Assessment Numerical Evaluation (SANE) scores after rotator cuff repair, rotator cuff revision, and SLAP repair. This study was a retrospective review of a prospectively filled database of 262 patients who underwent arthroscopic surgery for rotator cuff tears or SLAP lesions between 1999 and 2007. All patients were operated on by the same surgeon, with a minimum follow-up of 2 years. The patient database included preoperative and outcome measures, such as pain, range of motion, and notably postoperative ASES and SANE scores. Any patient with incomplete data was removed from the study. Three groups were identified: primary rotator cuff repair (n = 135), rotator cuff revision (n = 73), and SLAP repair (n = 54). The overall mean ASES and SANE scores after surgery were 82.7 (± 20.2) and 83.3 (± 19.6), respectively. The Pearson correlation coefficient (r) between both scores was 0.8 (P < .001), demonstrating a very good correlation. In subgroup analysis, the correlation was highest in the cuff revision group (r = 0.88; P < .001) followed by the SLAP group (r = 0.78; P < .001) and primary cuff group (r = 0.75; P < .001). This study shows that there is a significant correlation between postoperative SANE and ASES rating methods in rotator cuff and SLAP repairs. We recommend the SANE score as a reliable outcome indicator for iterative follow-up, which can then be combined with a more clinically informative score such as the ASES or other process-based scores for preoperative and final workup. Level III, retrospective comparative study. Copyright © 2015 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  14. Clinical outcomes of robotic mitral valve repair: a single-center experience in Korea

    PubMed Central

    Kim, Ho Jin; Kim, Joon Bum; Jung, Sung-Ho

    2017-01-01

    Background Since the inception of robotic mitral valve repair (MV) in 2007 at our institution, it has become an acceptable surgical option with proven efficacy and safety. The objective of this study is to analyze the early and long-term clinical outcomes of patients undergoing robotic MV repair. Methods A total of 310 patients (aged 48.4±13.7 years, 201 males) undergoing robotic MV repair using the da Vinci system (Intuitive Surgical, Inc., Sunnyvale, CA) between August 2007 and December 2015 in our institution were evaluated. The preoperative demographics, operative profiles and postoperative outcomes including follow-up echocardiographic results were analyzed. Results Successful MV repair was achieved in 98.4% (n=305) of patients, with no significant residual mitral regurgitation (MR) postoperatively. There were no early postoperative deaths. Early postoperative complications included: stroke (n=3, 1.0%), new onset dialysis (n=1, 0.3%) and reoperation (n=3, 1.0%). During a median follow-up of 55.7 months (inter-quartile range 30.3 to 81.3 months), six (1.9%) patients died, while four patients underwent late reoperation for mitral regurgitation (n=2) or infective endocarditis (n=2). Major event-free survival at five years was 87.6%. Late echocardiographic profiles (>6 months) were obtained in 295 (95.2%) patients. During follow-up, 32 (10.8%) patients developed significant mitral regurgitation (MR > grade 2), while freedom from significant MR at five years was 86.5%. Conclusions Robotic MV repair is a safe procedure with acceptable postoperative results, including low early postoperative morbidity and mortality and acceptable long-term repair durability. PMID:28203536

  15. Single-center ventral hernia repair with porcine dermis collagen implant.

    PubMed

    Boules, M; Strong, A T; Corcelles, R; Haskins, I N; Ilie, R; Wathen, C; Froylich, D; Sharma, G; Rodriguez, J; Rosenblatt, S; El-Hayek, K; Kroh, M

    2017-09-20

    This study aims to evaluate the outcomes and utilization of porcine acellular dermal collagen implant (PADCI) during VHR at a large tertiary referral center. Records of 5485 patients who underwent VIHR from June 1995 to August 2014 were retrospectively reviewed to identify patients >18 years of age who had VIHR with PADCI reinforcement. Use of multiple mesh reinforcement products, inguinal hernias, and hiatal hernias were exclusion criteria. The primary outcome was hernia recurrence, and secondary outcomes were early complications and surgical site occurrences (SSOs). Uni- and multivariate analyses assessed risk factors for recurrence after PADCI reinforced VIHR. There were 361 patients identified (54.5% female, mean age of 56.7 ± 12.5 years, and mean body mass index (BMI) of 33.0 ± 9.9 kg/m(2)). Hypertension (49.5%), diabetes (24.3%), and coronary artery disease (14.4%) were the most common comorbidities, as was active smoking (20.7%). Most were classified as American Association of Anesthesiologists (ASA) Class 3 (61.7%). Hernias were distributed across all grades of the ventral hernia working group (VHWG) grading system: grade I 93 (25.7%), grade II 51 (14.1%), grade III 113 (31.3%), and grade IV 6 (1.6%). Most VIHR were performed from an open approach (96.1%), and were frequently combined with concomitant surgical procedures (47.9%). Early postoperative complications (first 30 days) were reported in 39.0%, with 71 being SSO. Of the 19.7% of patients with SSO, there were 31 who required procedural intervention. After a mean follow-up of 71.5 ± 20.5 months, hernia recurrence was documented in 34.9% of patients. Age and male gender were predictors of recurrence on multivariate analysis. To the best of our knowledge, this is the largest retrospective single institutional study evaluating PADCI to date. Hernias repaired with PADCI were frequently in patients undergoing concomitant operations. Reinforcement with PADCI may be considered a temporary

  16. Single-row vs. double-row arthroscopic rotator cuff repair: clinical and 3 Tesla MR arthrography results.

    PubMed

    Tudisco, Cosimo; Bisicchia, Salvatore; Savarese, Eugenio; Fiori, Roberto; Bartolucci, Dario A; Masala, Salvatore; Simonetti, Giovanni

    2013-01-27

    Arthroscopic rotator cuff repair has become popular in the last few years because it avoids large skin incisions and deltoid detachment and dysfunction. Earlier arthroscopic single-row (SR) repair methods achieved only partial restoration of the original footprint of the tendons of the rotator cuff, while double-row (DR) repair methods presented many biomechanical advantages and higher rates of tendon-to-bone healing. However, DR repair failed to demonstrate better clinical results than SR repair in clinical trials. MR imaging at 3 Tesla, especially with intra-articular contrast medium (MRA), showed a better diagnostic performance than 1.5 Tesla in the musculoskeletal setting. The objective of this study was to retrospectively evaluate the clinical and 3 Tesla MRA results in two groups of patients operated on for a medium-sized full-thickness rotator cuff tear with two different techniques. The first group consisted of 20 patients operated on with the SR technique; the second group consisted of 20 patients operated on with the DR technique. All patients were evaluated at a minimum of 3 years after surgery. The primary end point was the re-tear rate at 3 Tesla MRA. The secondary end points were the Constant-Murley Scale (CMS), the Simple Shoulder Test (SST) scores, surgical time and implant expense. The mean follow-up was 40 months in the SR group and 38.9 months in the DR group. The mean postoperative CMS was 70 in the SR group and 68 in the DR group. The mean SST score was 9.4 in the SR group and 10.1 in the DR group. The re-tear rate was 60% in the SR group and 25% in the DR group. Leakage of the contrast medium was observed in all patients. To the best of our knowledge, this is the first report on 3 Tesla MRA in the evaluation of two different techniques of rotator cuff repair. DR repair resulted in a statistically significant lower re-tear rate, with longer surgical time and higher implant expense, despite no difference in clinical outcomes. We think that

  17. Investigation of the repair of single-strand breaks in human DNA using alkaline gel electrophoresis

    SciTech Connect

    Kovacs, E.; Langemann, H. )

    1990-11-01

    Unstimulated lymphocytes from eight healthy persons were exposed to 10-, 30-, and 100-Gy doses of 60Co gamma radiation. The repair of damaged DNA was measured by (1) alkaline gel electrophoresis (extracted DNA loaded on 0.25% agarose gel, run at 1 V/cm for 39-44 h) at 0, 1, and 2 h after exposure and (2) incorporation of (3H)thymidine into unstimulated lymphocytes in the presence of 2 mM hydroxyurea 1 and 2 h after exposure. Both methods--alkaline gel electrophoresis and thymidine incorporation--showed that repair was completed within 2 h.

  18. Replacing a Single-Pole Light Switch. Minor Electrical Home Repairs, Lesson Plan No. 3.

    ERIC Educational Resources Information Center

    Kawamura, Harry T.

    Designed as part of a 40-hour course in minor electrical home repairs, this 50-minute lesson is designed to enable the student to: (1) use a voltage tester to isolate electrical switching problems safely; (2) use simple hand tools to remove the defective switch without creating a shock hazard; (3) correctly identify the type of wire, current,…

  19. Replacing a Single-Pole Light Switch. Minor Electrical Home Repairs, Lesson Plan No. 3.

    ERIC Educational Resources Information Center

    Kawamura, Harry T.

    Designed as part of a 40-hour course in minor electrical home repairs, this 50-minute lesson is designed to enable the student to: (1) use a voltage tester to isolate electrical switching problems safely; (2) use simple hand tools to remove the defective switch without creating a shock hazard; (3) correctly identify the type of wire, current,…

  20. Distinct spatiotemporal patterns and PARP dependence of XRCC1 recruitment to single-strand break and base excision repair

    PubMed Central

    Campalans, Anna; Kortulewski, Thierry; Amouroux, Rachel; Menoni, Hervé; Vermeulen, Wim; Radicella, J. Pablo

    2013-01-01

    Single-strand break repair (SSBR) and base excision repair (BER) of modified bases and abasic sites share several players. Among them is XRCC1, an essential scaffold protein with no enzymatic activity, required for the coordination of both pathways. XRCC1 is recruited to SSBR by PARP-1, responsible for the initial recognition of the break. The recruitment of XRCC1 to BER is still poorly understood. Here we show by using both local and global induction of oxidative DNA base damage that XRCC1 participation in BER complexes can be distinguished from that in SSBR by several criteria. We show first that XRCC1 recruitment to BER is independent of PARP. Second, unlike SSBR complexes that are assembled within minutes after global damage induction, XRCC1 is detected later in BER patches, with kinetics consistent with the repair of oxidized bases. Third, while XRCC1-containing foci associated with SSBR are formed both in eu- and heterochromatin domains, BER complexes are assembled in patches that are essentially excluded from heterochromatin and where the oxidized bases are detected. PMID:23355608

  1. New single nucleotide polymorphisms (SNPs) in homologous recombination repair genes detected by microarray analysis in Polish breast cancer patients.

    PubMed

    Romanowicz, Hanna; Strapagiel, Dominik; Słomka, Marcin; Sobalska-Kwapis, Marta; Kępka, Ewa; Siewierska-Górska, Anna; Zadrożny, Marek; Bieńkiewicz, Jan; Smolarz, Beata

    2016-11-30

    Breast cancer is the most common cause of malignancy and mortality in women worldwide. This study aimed at localising homologous recombination repair (HR) genes and their chromosomal loci and correlating their nucleotide variants with susceptibility to breast cancer. In this study, authors analysed the association between single nucleotide polymorphisms (SNPs) in homologous recombination repair genes and the incidence of breast cancer in the population of Polish women. Blood samples from 94 breast cancer patients were analysed as test group. Individuals were recruited into the study at the Department of Oncological Surgery and Breast Diseases of the Institute of the Polish Mother's Memorial Hospital in Lodz, Poland. Healthy controls (n = 500) were obtained from the Biobank Laboratory, Department of Molecular Biophysics, University of Lodz. Then, DNA of breast cancer patients was compared with one of the disease-free women. The test was supported by microarray analysis. Statistically significant correlations were identified between breast cancer and 3 not described previously SNPs of homologous recombination repair genes BRCA1 and BRCA2: rs59004709, rs4986852 and rs1799950. Further studies on larger groups are warranted to support the hypothesis of correlation between the abovementioned genetic variants and breast cancer risk.

  2. Biomechanical evaluation of knee kinematics after anatomic single- and anatomic double-bundle ACL reconstructions with medial meniscal repair.

    PubMed

    Lorbach, Olaf; Kieb, Matthias; Domnick, Christoph; Herbort, Mirco; Weyers, Imke; Raschke, Michael; Engelhardt, Martin

    2015-09-01

    To evaluate knee laxity after anatomic ACL reconstruction with additional suture repair of a medial meniscus tear. Kinematics of the intact knee were determined in 12 human cadaver specimens in response to a 134-N anterior tibial load (aTT) and a combined rotatory load of 10 Nm valgus and 4 Nm internal tibial rotation (aTTPS) using a robotic/universal force moment sensor testing system. Subsequently, the ACL was resected following the creation of a standardized tear of the medial meniscus, a standard meniscus repair and an ACL reconstruction using an anatomic single-bundle (6) or an anatomic double-bundle technique (6). Knee kinematics were determined following every sub-step. Significant increase of aTT in the ACL-deficient knee was found (p ≤ 0.001) with a further increase in the ACL-deficient knee with additional medial meniscal rupture (p ≤ 0.001). ACL reconstructions significantly decreased aTT compared with the ACL and meniscus-ruptured knee. No significant differences were seen between the intact knee and the ACL-reconstructed knee with additional meniscal repair (p < 0.05). In response to a simulated pivot shift, aTTPS in the intact knee significantly increased in the ACL-deficient knee and meniscus-ruptured knee (p = 0.005). No significant differences in knee kinematics were found between SB as well as DB ACL reconstruction with additional medial meniscal repair compared with the intact knee. Comparison of SB versus DB ACL reconstruction did not reveal any significant differences in a simulated Lachman test or simulated pivot shift test (n.s.). aTT as well as aTTPS significantly increased with ACL deficiency compared with the intact knee; additional medial meniscal rupture further increased aTT. Anatomic ACL reconstruction with medial meniscal repair did not reveal significant differences in knee kinematics compared with the intact knee. Comparison of anatomic SB versus DB ACL reconstruction with additional repair of the medial meniscus did not show

  3. [Use of artificial circulation during prosthetic repair of the abdominal aorta in single-step operations (a meta-analysis)].

    PubMed

    Belov, Iu V; Bazylev, V V; Savichev, D D

    2009-01-01

    To assess the risk of complications during the use of extracorporeal circulation at the stage of prosthetic reconstruction of the abdominal aorta in single-step interventions we carried out a systemic analysis of 20 publications mentioning the use of artificial circulation during aortic reconstruction, as well as analysed the works wherein aortic prosthetic repair was performed after artificial circulation was discontinued. The postoperative mortality rate in single-step interventions with the use of artificial circulation at the stage of aortic prosthetic reconstructions ranges from 0 to 25%, and that without artificial circulation varies from 0- 6.7%. A meta-analysis of the publications showed that the cumulative relative risk for development of complications is 3.14 times greater in those patients who at the stage of aortic reconstruction continued receiving artificial circulation. The use of artificial circulation does not decrease the incidence rate of myocardial infarction neither does it influence the rate of development of haemorrhage or purulent complications. However, the use of artificial circulation at the stage of prosthetic reconstruction of the abdominal aorta considerably increases the incidence rate of respiratory, renal and neurological complications. Hence, the advantages of using artificial circulation are levelled by high incidence of complications, while the opinion that the use of artificial circulation at the stage of prosthetic repair of the abdominal aorta decreases the incidence of myocardial infarction was not confirmed in our systemic review, therefore the use of extracorporeal circulation in single-step operations should be well-grounded.

  4. Randomized controlled trial of glove perforation in single- and double-gloving in episiotomy repair after vaginal delivery.

    PubMed

    Punyatanasakchai, Piyaphan; Chittacharoen, Apichart; Ayudhya, Nathpong Israngura Na

    2004-10-01

    The aims of the study presented here were to compare the rate of glove perforation between single-gloving and double-gloving methods, and the time of operation and level of surgeon in episiotomy repair after vaginal delivery. A prospective randomized controlled trial was performed from the beginning of May to the end of December, 2002 at Ramathibodi Hospital. A comparison of glove perforation between single-gloving and double-gloving methods was performed. Glove perforations were tested by filling each glove with water. Glove perforation rate, position of perforation, time of operation and surgeon level of experience were analyzed. One hundred and fifty sets of double-gloving method and 150 sets of single-gloving method were evaluated. The glove perforation rates were 4.6 and 18% in double-inner gloves and single-gloves, respectively, with statistical difference (P < 0.05). There was no significant difference between glove perforation rates in double-outer gloves (22.6%) and single-gloves (18%). There was matched perforation of the same finger of both outer and inner gloves in 2% of all double-inner gloves. The frequency of glove perforation was classified by the surgeon's level of experience and time of operation was no difference in each level. The double-gloving method significantly reduced the risk of exposure of the surgeon's hand to the patient's blood, when compared with the single-gloving method in episiotomy repair. There were no differences in the rate of glove perforations compared to the time of operation and level of surgeon.

  5. Single vs. double layer suturing method repair of the urethral plate in the rabbit model of hypospadias

    PubMed Central

    Shirazi, Mehdi; Rahimi, Mohammad

    2016-01-01

    Introduction There are different methods of urethroplasty in hypospadias. The present study aimed to compare the repair of the urethral plate by single vs. double layer suturing. Material and methods Fifteen male rabbits were assigned to the control, single layer, and double layer urethral plate suturing groups (n = 5). Experimental hypospadias was induced in the second and third groups and the urethral plates were sutured. After two weeks, the penis was dissected out and underwent histopathological processing. Stereological studies were applied to obtain quantitative histological data regarding the structure of the urethra and the related part of the corpus spongiosum. Results Volume density of the urethral epithelium (the fraction of unit volume of the urethra occupied by its epithelium) was higher in the single layer suturing group when compared to the double layer or control groups (p <0.01). Additionally, the volume density of the urethral lumen (the fraction of the corpus spongiosum that is occupied by the urethral lumen) in the single versus the double layer suturing groups was respectively 2.4 and 2 folds higher than that in the control group (p <0.01). Besides, the volume density of the lumen was significantly higher in the single layer suturing when compared to the double layer suturing group (p <0.01). However, no significant difference was observed among the study groups regarding the volume density of the collagen and vessels in the incised site of the penis which implied that the fraction of the urethra and surrounding corpus spongiosum was occupied by collagen and vessels. Conclusions Urethral plate repair by the single layer suturing method could be accompanied by higher epithelialization and wider lumen in the rabbit model of hypospadias. PMID:28127462

  6. Primary Repair of Traumatic Distal Biceps Ruptures in a Military Population: Clinical Outcomes of Single- Versus 2-Incision Technique.

    PubMed

    Waterman, Brian R; Navarro-Figueroa, Lorenzo; Owens, Brett D

    2017-09-01

    To determine the success of distal biceps repair in a high-demand military population and to comparatively evaluate the perioperative risk profile, functional results, and adverse patient outcomes of a single- versus 2-incision technique within this high-risk group. Between 2007-2013, all military service members undergoing primary surgical repair for distal biceps rupture through the Military Health System were isolated. Patients with allograft tendon reconstruction, revision procedures, nonmilitary status, and/or follow-up of less than 24 month were excluded. Demographic data (age, limb dominance) and surgical variables (time to surgery, surgical technique) were extracted, and rates of perioperative complications, rerupture, reoperation, revision, and inability to return to preinjury function were recorded. Logistic regression analysis was performed to evaluate for prognostic risk factors, whereas the Fisher exact test was used for comparative analysis. A total of 290 patients met the inclusion criteria, including 44 (15.2%) with a delayed presentation; all patients were men, with an average age of 38.9 years (range, 20-61 years). A single-incision technique was performed in 75.4% (n = 214) versus a 2-incision technique in 24.6% (n = 70), and a cortical button was the predominant fixation construct (73.4%). Reruptures occurred in 7 patients (2.4%), and 3 individuals (1.0%) had significant elbow dysfunction postoperatively. When we compared the overall complication rates, the 2-incision technique (7.1%, n = 5) was not significantly different from the single-incision repair (16.4%, n = 35; P = .0732). Tobacco use was significantly associated with risk of rerupture (odds ratio, 4.86; P = .0423) or combined surgical and clinical failures (odds ratio, 5.64; P = .0091), whereas age, limb dominance, time to surgery, fixation construct, and surgical technique were not statistically significant (P > .05). Among active patients, a single-volar incision technique

  7. A Modified Single-Step Method to Repair a Central Defect of the Upper Lip.

    PubMed

    Moreno García, Carlos; González-García, Raúl; Moreno-Sánchez, Manuel; García, María Asunción Pons; Monje, Florencio

    2016-12-01

    Defects in the central region of the upper lip are difficult to repair. Several techniques have been described, many of them requiring a second surgical procedure to obtain acceptable aesthetic results. A patient with a soft defect in the central region of the upper lip following aggression by human bite is presented. To repair the defect, the principles described by Goldstein for lateral lip defects were used (Goldstein in Plast Reconstr Surg 85(3):446-452, 1990; Robotti et al. in J Plast Reconstr Aesthet Surg 63:431-439, 2010). In this particular case, two full-thickness advancing miomucosal flaps from the vermilion of the upper lip were used with predictable aesthetic results.

  8. Single-Nucleotide Polymorphisms of Genes Involved in Repair of Oxidative DNA Damage and the Risk of Recurrent Depressive Disorder

    PubMed Central

    Czarny, Piotr; Kwiatkowski, Dominik; Toma, Monika; Gałecki, Piotr; Orzechowska, Agata; Bobińska, Kinga; Bielecka-Kowalska, Anna; Szemraj, Janusz; Berk, Michael; Anderson, George; Śliwiński, Tomasz

    2016-01-01

    Background Depressive disorder, including recurrent type (rDD), is accompanied by increased oxidative stress and activation of inflammatory pathways, which may induce DNA damage. This thesis is supported by the presence of increased levels of DNA damage in depressed patients. Such DNA damage is repaired by the base excision repair (BER) pathway. BER efficiency may be influenced by polymorphisms in BER-related genes. Therefore, we genotyped nine single-nucleotide polymorphisms (SNPs) in six genes encoding BER proteins. Material/Methods Using TaqMan, we selected and genotyped the following SNPs: c.-441G>A (rs174538) of FEN1, c.2285T>C (rs1136410) of PARP1, c.580C>T (rs1799782) and c.1196A>G (rs25487) of XRCC1, c.*83A>C (rs4796030) and c.*50C>T (rs1052536) of LIG3, c.-7C>T (rs20579) of LIG1, and c.-468T>G (rs1760944) and c.444T>G (rs1130409) of APEX1 in 599 samples (288 rDD patients and 311 controls). Results We found a strong correlation between rDD and both SNPs of LIG3, their haplotypes, as well as a weaker association with the c.-468T>G of APEXI which diminished after Nyholt correction. Polymorphisms of LIG3 were also associated with early onset versus late onset depression, whereas the c.-468T>G polymorphism showed the opposite association. Conclusions The SNPs of genes involved in the repair of oxidative DNA damage may modulate rDD risk. Since this is an exploratory study, the results should to be treated with caution and further work needs to be done to elucidate the exact involvement of DNA damage and repair mechanisms in the development of this disease. PMID:27866211

  9. Single-Nucleotide Polymorphisms of Genes Involved in Repair of Oxidative DNA Damage and the Risk of Recurrent Depressive Disorder.

    PubMed

    Czarny, Piotr; Kwiatkowski, Dominik; Toma, Monika; Gałecki, Piotr; Orzechowska, Agata; Bobińska, Kinga; Bielecka-Kowalska, Anna; Szemraj, Janusz; Berk, Michael; Anderson, George; Śliwiński, Tomasz

    2016-11-20

    BACKGROUND Depressive disorder, including recurrent type (rDD), is accompanied by increased oxidative stress and activation of inflammatory pathways, which may induce DNA damage. This thesis is supported by the presence of increased levels of DNA damage in depressed patients. Such DNA damage is repaired by the base excision repair (BER) pathway. BER efficiency may be influenced by polymorphisms in BER-related genes. Therefore, we genotyped nine single-nucleotide polymorphisms (SNPs) in six genes encoding BER proteins. MATERIAL AND METHODS Using TaqMan, we selected and genotyped the following SNPs: c.-441G>A (rs174538) of FEN1, c.2285T>C (rs1136410) of PARP1, c.580C>T (rs1799782) and c.1196A>G (rs25487) of XRCC1, c.*83A>C (rs4796030) and c.*50C>T (rs1052536) of LIG3, c.-7C>T (rs20579) of LIG1, and c.-468T>G (rs1760944) and c.444T>G (rs1130409) of APEX1 in 599 samples (288 rDD patients and 311 controls). RESULTS We found a strong correlation between rDD and both SNPs of LIG3, their haplotypes, as well as a weaker association with the c.-468T>G of APEXI which diminished after Nyholt correction. Polymorphisms of LIG3 were also associated with early onset versus late onset depression, whereas the c.-468T>G polymorphism showed the opposite association. CONCLUSIONS The SNPs of genes involved in the repair of oxidative DNA damage may modulate rDD risk. Since this is an exploratory study, the results should to be treated with caution and further work needs to be done to elucidate the exact involvement of DNA damage and repair mechanisms in the development of this disease.

  10. [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.

  11. Single-centre experience with mitral valve repair in asymptomatic patients with severe mitral valve regurgitation†

    PubMed Central

    van Leeuwen, Wouter J.; Head, Stuart J.; de Groot-de Laat, Lotte E.; Geleijnse, Marcel L.; Bogers, Ad J.J.C.; Van Herwerden, Lex A.; Kappetein, A. Pieter

    2013-01-01

    OBJECTIVES Guidelines recommend surgical mitral valve repair in selected patients with asymptomatic severe mitral valve regurgitation (MR), but the role of repair remains a matter of debate. Survival analyses of operated asymptomatic patients have been reported, but long-term haemodynamics and quality of life are not well defined. The aim of this study was to report the long-term follow-up focusing on these aspects. METHODS Our database identified patients who underwent primary isolated mitral valve repair for severe MR and were asymptomatic by New York Heart Association Class I and in sinus rhythm. To obtain sufficient length of follow-up, only patients operated on before 2006 returned for an echocardiogram and quality-of-life assessment (SF-36). RESULTS Between May 1991 and December 2005, 46 asymptomatic patients with severe MR and a normal left ventricular function (ejection fraction >60%) were operated on. Mean age was 50.2 ± 13.2 years and 89% of patients were male. There were no operative deaths. Mean follow-up was 8.4 ± 3.9 years with 386 patient-years, survival was 93.3% at 12 years and comparable with the general age-matched Dutch population. Follow-up echocardiography showed that 92% had no to mild MR, and 3 patients had moderate MR. Left ventricular function was good/impaired/moderate in 66/29/5% of patients. Quality-of-life SF-36 assessment showed that mean physical and mental health components were 83 ± 17 and 79 ± 17, which was comparable with that of the general age- and gender-matched Dutch population. CONCLUSIONS Our experience shows that mitral valve repair for severe MR in asymptomatic patients is safe, and has satisfactory long-term survival with a low recurrence rate of MR, good left ventricular function, and excellent quality of life that is comparable with the general Dutch population. PMID:23442941

  12. Lipid domain–dependent regulation of single-cell wound repair

    PubMed Central

    Vaughan, Emily M.; You, Jae-Sung; Elsie Yu, Hoi-Ying; Lasek, Amber; Vitale, Nicolas; Hornberger, Troy A.; Bement, William M.

    2014-01-01

    After damage, cells reseal their plasma membrane and repair the underlying cortical cytoskeleton. Although many different proteins have been implicated in cell repair, the potential role of specific lipids has not been explored. Here we report that cell damage elicits rapid formation of spatially organized lipid domains around the damage site, with different lipids concentrated in different domains as a result of both de novo synthesis and transport. One of these lipids—diacylglycerol (DAG)—rapidly accumulates in a broad domain that overlaps the zones of active Rho and Cdc42, GTPases that regulate repair of the cortical cytoskeleton. Formation of the DAG domain is required for Cdc42 and Rho activation and healing. Two DAG targets, protein kinase C (PKC) β and η, are recruited to cell wounds and play mutually antagonistic roles in the healing process: PKCβ participates in Rho and Cdc42 activation, whereas PKCη inhibits Rho and Cdc42 activation. The results reveal an unexpected diversity in subcellular lipid domains and the importance of such domains for a basic cellular process. PMID:24790096

  13. Triple-Loaded Single-Row Versus Suture-Bridge Double-Row Rotator Cuff Tendon Repair With Platelet-Rich Plasma Fibrin Membrane: A Randomized Controlled Trial.

    PubMed

    Barber, F Alan

    2016-05-01

    To compare the structural healing and clinical outcomes of triple-loaded single-row with suture-bridging double-row repairs of full-thickness rotator cuff tendons when both repair constructs are augmented with platelet-rich plasma fibrin membrane. A prospective, randomized, consecutive series of patients diagnosed with full-thickness rotator cuff tears no greater than 3 cm in anteroposterior length were treated with a triple-loaded single-row (20) or suture-bridging double-row (20) repair augmented with platelet-rich plasma fibrin membrane. The primary outcome measure was cuff integrity by magnetic resonance imaging (MRI) at 12 months postoperatively. Secondary clinical outcome measures were American Shoulder and Elbow Surgeons, Rowe, Simple Shoulder Test, Constant, and Single Assessment Numeric Evaluation scores. The mean MRI interval was 12.6 months (range, 12-17 months). A total of 3 of 20 single-row repairs and 3 of 20 double-row repairs (15%) had tears at follow-up MRI. The single-row group had re-tears in 1 single tendon repair and 2 double tendon repairs. All 3 tears failed at the original attachment site (Cho type 1). In the double-row group, re-tears were found in 3 double tendon repairs. All 3 tears failed medial to the medial row near the musculotendinous junction (Cho type 2). All clinical outcome measures were significantly improved from the preoperative level (P < .0001), but there was no statistical difference between groups postoperatively. There is no MRI difference in rotator cuff tendon re-tear rate at 12 months postsurgery between a triple-loaded single-row repair or a suture-bridging double-row repair when both are augmented with platelet-rich plasma fibrin membrane. No difference could be demonstrated between these repairs on clinical outcome scores. I, Prospective randomized study. Copyright © 2016 Arthroscopy Association of North America. All rights reserved.

  14. Large inverted repeats in the vicinity of a single double-strand break strongly affect repair in yeast diploids lacking Rad51.

    PubMed

    Downing, Brandon; Morgan, Rachel; VanHulle, Kelly; Deem, Angela; Malkova, Anna

    2008-10-14

    DNA double-strand breaks (DSBs) are critical lesions that can lead to cell death or chromosomal rearrangements. Rad51 is necessary for most mitotic and meiotic DSB repair events, although a number of RAD51-independent pathways exist. Previously, we described DSB repair in rad51Delta yeast diploids that was stimulated by a DNA region termed "facilitator of break-induced replication" (FBI) located approximately 30kb from the site of an HO-induced DSB. Here, we demonstrate that FBI is a large inverted DNA repeat that channels the repair of DSBs into the single-strand annealing-gross chromosomal rearrangements (SSA-GCR) pathway. Further, analysis of DSB repair in rad54Delta cells allowed us to propose that the SSA-GCR repair pathway is suppressed in the presence of Rad51p. Therefore, an additional role of Rad51 might be to protect eukaryotic genomes from instabilities by preventing chromosomal rearrangements.

  15. Sirtuin 6 (SIRT6) rescues the decline of homologous recombination repair during replicative senescence

    PubMed Central

    Mao, Zhiyong; Tian, Xiao; Van Meter, Michael; Ke, Zhonghe; Gorbunova, Vera; Seluanov, Andrei

    2012-01-01

    Genomic instability is a hallmark of aging tissues. Genomic instability may arise from the inefficient or aberrant function of DNA double-stranded break (DSB) repair. DSBs are repaired by homologous recombination (HR) and nonhomologous DNA end joining (NHEJ). HR is a precise pathway, whereas NHEJ frequently leads to deletions or insertions at the repair site. Here, we used normal human fibroblasts with a chromosomally integrated HR reporter cassette to examine the changes in HR efficiency as cells progress to replicative senescence. We show that HR declines sharply with increasing replicative age, with an up to 38-fold decrease in efficiency in presenescent cells relative to young cells. This decline is not explained by a reduction of the number of cells in S/G2/M stage as presenescent cells are actively dividing. Expression of proteins involved in HR such as Rad51, Rad51C, Rad52, NBS1, and Sirtuin 6 (SIRT6) diminished with cellular senescence. Supplementation of Rad51, Rad51C, Rad52, and NBS1 proteins, either individually or in combination, did not rescue the senescence-related decline of HR. However, overexpression of SIRT6 in “middle-aged” and presenescent cells strongly stimulated HR repair, and this effect was dependent on mono-ADP ribosylation activity of poly(ADP-ribose) polymerase (PARP1). These results suggest that in aging cells, the precise HR pathway becomes repressed giving way to a more error-prone NHEJ pathway. These changes in the processing of DSBs may contribute to age-related genomic instability and a higher incidence of cancer with age. SIRT6 activation provides a potential therapeutic strategy to prevent the decline in genome maintenance. PMID:22753495

  16. 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.

  17. Objective assessment of surgical training in flexor tendon repair: the utility of a low-cost porcine model as demonstrated by a single-subject research design.

    PubMed

    Zetlitz, Elisabeth; Wearing, Scott Cameron; Nicol, Alexander; Hart, Andrew Mackay

    2012-01-01

    This study evaluated the utility of a porcine flexor tendon model and standard biomechanical testing procedures to quantify the acquisition of surgical skills associated with Zone II flexor tendon repair in a trainee by benchmarking task performance outcomes relative to evidence-based standards. Single-subject repeated measures research design. Bench-top set-up of apparatus undertaken in a University Research laboratory. After initial directed learning, a trainee repaired 70 fresh flexor digitorum profundus tendons within the flexor sheath using either a Pennington or ventral-locking-loop modification of a two-strand Kessler core repair. Tendon repairs were then preconditioned and distracted to failure. Key biomechanical parameters of the repair, including the ultimate tensile strength (UTS), yield strength, 3 mm gap force and stiffness, were calculated. Repairs were divided into 3 categories, early (first 10 days), intermediate (ensuing 10 days), and late repairs (final 10 days), and potential changes in repair properties over the training period were evaluated using a general linear modeling approach. There was a significant change in the mechanical characteristics of the repairs over the training period, evidencing a clear learning effect (p < 0.05). Irrespective of the repair technique employed, early and intermediate repairs were characterized by a significantly lower UTS (29% and 20%, respectively), 3 mm gap (21% and 16%, respectively), and yield force (18% and 23%, respectively), but had a higher stiffness (33% and 38%, respectively) than late repairs (p < 0.05). The UTS of late repairs (47-48 N) were comparable to those published within the literature (45-51 N), suggesting surgical competence of the trainee. This simple, low-cost porcine model appears to be useful for providing preclinical training in flexor tendon repair techniques and has the potential to provide a quantitative index to evaluate the competency of surgical trainees. Further research is now

  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. 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...

  20. Saccharomyces cerevisiae Ku70 potentiates illegitimate DNA double-strand break repair and serves as a barrier to error-prone DNA repair pathways.

    PubMed Central

    Boulton, S J; Jackson, S P

    1996-01-01

    Ku, a heterodimer of polypeptides of approximately 70 kDa and 80 kDa (Ku70 and Ku80, respectively), binds avidly to DNA double-strand breaks (DSBs). Mammalian cells defective in Ku are hypersensitive to ionizing radiation due to a deficiency in DSB repair. Here, we show that the simple inactivation of the Saccharomyces cerevisiae Ku70 homologue (Yku70p), does not lead to increased radiosensitivity. However, yku70 mutations enhance the radiosensitivity of rad52 strains, which are deficient in homologous recombination. Through establishing a rapid and reproducible in vivo plasmid rejoining assay, we show that Yku70p plays a crucial role in the repair of DSBs bearing cohesive termini. Whereas this damage is repaired accurately in YKU70 backgrounds, in yku70 mutant strains terminal deletions of up to several hundred bp occur before ligation ensues. Interestingly, this error-prone DNA repair pathway utilizes short homologies between the two recombining molecules and is thus highly reminiscent of a predominant form of DSB repair that operates in vertebrates. These data therefore provide evidence for two distinct and evolutionarily conserved illegitimate recombination pathways. One of these is accurate and Yku70p-dependent, whereas the other is error-prone and Yku70-independent. Furthermore, our studies suggest that Yku70 promotes genomic stability both by promoting accurate DNA repair and by serving as a barrier to error-prone repair processes. Images PMID:8890183

  1. The scapular, parascapular, and latissimus dorsi flap as a single osteomyocutaneous flap for repair of complex oral defects.

    PubMed

    Janus, Jeffrey R; Carlson, Matthew L; Moore, Eric J

    2012-01-01

    Complex composite defects of the oral cavity are often created due to en bloc resection of malignant tumors. These defects can involve bone, soft tissue, oral mucosa, and external skin, posing a reconstructive challenge to the microvascular surgeon. Though advances have been made in free tissue transfer via piggybacking techniques and double free-flaps, increases in operative time and morbidity remain limiting factors. Likewise, advancements in single composite flaps (e.g., double-skin paddle fibular free-flap) allow for a single donor site, but limit workable tissue. This report describes our experience with the scapular, parascapular, and latissimus dorsi (SPLD) as a combined single unit osteomyocutaneous flap for composite reconstruction of complex oral defects. A case example is subsequently reviewed for clinical correlation. This is an operative techniques article describing the use of the SPLD single multi-tissue flap for repair of complex oral defects. Cadaveric dissection was performed for instructional purposes. Case example was given for clinical correlation. Relevant history, anatomy, procedural details, and possible complications are presented and subsequently correlated to the case example. A SPLD free-flap as a single multi-tissue flap is a viable and beneficial option for reconstruction of complex oral defects. It provides the volume of tissue necessary to fill composite defects and exists as an alternative to multi-flap procedures, which carry a longer operative time and multiple donor site morbidity.

  2. Double-stranded break can be repaired by single-stranded oligonucleotides via the ATM/ATR pathway in mammalian cells.

    PubMed

    Wang, Zai; Zhou, Zhong-Jun; Liu, De-Pei; Huang, Jian-Dong

    2008-01-01

    Single-stranded oligonucleotide (SSO)-mediated gene modification is a newly developed tool for site-specific gene repair in mammalian cells; however, the corrected cells always show G2/M arrest and cannot divide to form colonies. This phenomenon and the unclear mechanism seriously challenge the future application of this technique. In this study, we developed an efficient SSO-mediated DNA repair system based on double-stranded break (DSB) induction. We generated a mutant EGFP gene with insertions of 24 bp to 1.6 kb in length as a reporter integrated in mammalian cell lines. SSOs were successfully used to delete the insertion fragments upon DSB induction at a site near the insertion. We demonstrated that this process is dependent on the ATM/ATR pathway. Importantly, repaired cell clones were viable. Effects of deletion length, SSO length, strand bias, and SSO modification on gene repair frequency were also investigated.

  3. A modified Chevrel technique for ventral hernia repair: long-term results of a single centre cohort.

    PubMed

    Mommers, E H H; Leenders, B J M; Leclercq, W K G; de Vries Reilingh, T S; Charbon, J A

    2017-08-01

    To evaluate the short- and long-term results after a modified Chevrel technique for midline incisional hernia repair, regarding surgical technique, hospital stay, wound complications, recurrence rate, and postoperative quality of life. These results will be compared to the literature derived reference values regarding the original and modified Chevrel techniques. In this large retrospective, single surgeon, single centre cohort all modified Chevrel hernia repairs between 2000 and 2012 were identified. Results were obtained by reviewing patients' medical charts. Postoperative quality of life was measured using the Carolina Comfort Scale. A multi-database literature search was conducted to compare the results of our series to the literature based reference values. One hundred and fifty-five patients (84 male, 71 female) were included. Eighty patients (52%) had a large incisional hernia (width ≥ 10 cm) according the definition of the European Hernia Society. Fourteen patients (9%) underwent a concomitant procedure. Median length-of-stay was 5 days. Within 30 days postoperative 36 patients (23.2%) had 39 postoperative complications of which 30 were mild (CDC I-II), and nine severe (CDC III-IV). Thirty-one surgical site occurrences were observed in thirty patients (19.4%) of which the majority were seroma (16 patients 10.3%). There was no hernia-related mortality during follow-up. Recurrence rate was 1.8% after a median follow-up of 52 months (12-128 months). Postoperative quality of life was rated excellent. The modified Chevrel technique for midline ventral hernias results in a moderate complication rate, low recurrence rate and high rated postoperative quality of life.

  4. Excellent healing rates and patient satisfaction after arthroscopic repair of medium to large rotator cuff tears with a single-row technique augmented with bone marrow vents.

    PubMed

    Dierckman, Brian D; Ni, Jake J; Karzel, Ronald P; Getelman, Mark H

    2017-06-24

    This study evaluated the repair integrity and patient clinical outcomes following arthroscopic rotator cuff repair of medium to large rotator cuff tears using a single-row technique consisting of medially based, triple-loaded anchors augmented with bone marrow vents in the rotator cuff footprint lateral to the repair. This is a retrospective study of 52 patients (53 shoulders) comprising 36 males and 16 females with a median age of 62 (range 44-82) with more than 24-month follow-up, tears between 2 and 4 cm in the anterior-posterior dimension and utilizing triple-loaded anchors. Mann-Whitney test compared Western Ontario Rotator Cuff (WORC) outcome scores between patients with healed and re-torn cuff repairs. Multivariate logistic regression analysed association of variables with healing status and WORC score. Cuff integrity was assessed on MRI, read by a musculoskeletal fellowship-trained radiologist. Magnetic resonance imaging (MRI) demonstrated an intact repair in 48 of 53 shoulders (91%). The overall median WORC score was 95.7 (range 27.6-100.0). A significant difference in WORC scores were seen between patients with healed repairs 96.7 (range 56.7-100.0) compared with a re-tear 64.6 (27.6-73.8), p < 0.00056. Arthroscopic repair of medium to large rotator cuff tears using a triple-loaded single-row repair augmented with bone marrow vents resulted in a 91% healing rate by MRI and excellent patient reported clinical outcomes comparable to similar reported results in the literature. IV.

  5. Outcome of complete primary bladder exstrophy repair: single-center experience.

    PubMed

    Shoukry, A I; Ziada, A M; Morsi, H A; Habib, E I; Aref, A; Badawy, H A; Eissa, M; Daw, M

    2009-12-01

    Reconstruction of bladder exstrophy remains a challenge. We evaluated our experience with complete primary repair in classic bladder exstrophy. A retrospective data review was conducted of bladder exstrophy patients presenting at our institution between May 2000 and September 2007. Fifty-one patients (21 females and 30 males) with classic bladder exstrophy were included. Age of presentation ranged from 24h to 14 months. Mean follow up was 3 years (1 month-7 years). Patients were evaluated for continence, upper tract dilatation and cosmetic result. Eight patients (15.6%) had failed closures and six (11.7%) had fistulae. Evaluation of continence excluded 16 patients not followed up at our center. Thirty-seven percent were continent on clean intermittent catheterization after the age of 5 years. Patients became dry only after augmentation cystoplasty. Upper tract changes were mild during our study with all patients having normal serum creatinine. Patients may require more than one procedure for reconstruction. In our series, augmentation was required to achieve acceptable dryness. Early promising results with dry intervals in young patients did not translate to continence in older patients.

  6. 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

  7. Long-term results of the single-patch repair technique for sinus venosus atrial septal defects.

    PubMed

    Temizkan, Veysel; Ugur, Murat; Alp, Ibrahim; Ucak, Alper; Yilmaz, Ahmet Turan

    2013-04-01

    Anomalous pulmonary venous drainage commonly accompanies sinus venosus atrial septal defects (SVASDs). Many techniques have been reported for avoiding postoperative complications, such as narrowing of the superior vena cava (SVC) or the pulmonary system, and arrhythmia. We perform a single V-Y pericardial patch plasty repair technique for SVASDs. The purpose of this study is to report on the long-term results of this surgical technique. We retrospectively analyzed patients who had a diagnosis of ASD and who underwent their operations between 2000 and 2010 at the Gulhane Military Medical Academy Haydarpasa Training Hospital. Thirty-nine of the patients had an anomalous pulmonary return, and the single pericardial patch technique had been performed in 32 of these patients. The mean (±SD) postoperative extubation time was 5 ± 1.6 hours. The mean drainage volume was 384 ± 137 mL. All patients were discharged from the hospital at a mean of 4.6 ± 1.1 days after their operation and were prescribed anticoagulants for 3 months. No perioperative or late-term mortality was observed. Patients were followed up for 6 months to 2 years. There were no residual shunts and no stenosis-related findings in the pulmonary venous system or the SVC. Use of the single pericardial patch plasty technique might lower complication rates in patients with SVASD, especially those who have not completed their growth.

  8. 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.

  9. Single Cell Analysis of Human RAD18-Dependent DNA Post-Replication Repair by Alkaline Bromodeoxyuridine Comet Assay

    PubMed Central

    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. PMID:23936422

  10. Effect of single- and double-row rotator cuff repair at the tendon-to-bone interface: preliminary results using an in vivo sheep model.

    PubMed

    Baums, M H; Schminke, B; Posmyk, A; Miosge, N; Klinger, H-M; Lakemeier, S

    2015-01-01

    The clinical superiority of the double-row technique is still a subject of controversial debate in rotator cuff repair. We hypothesised that the expression of different collagen types will differ between double-row and single-row rotator cuff repair indicating a faster healing response by the double-row technique. Twenty-four mature female sheep were randomly assembled to two different groups in which a surgically created acute infraspinatus tendon tear was fixed using either a modified single- or double-row repair technique. Shoulder joints from female sheep cadavers of identical age, bone maturity, and weight served as untreated control cluster. Expression of type I, II, and III collagen was observed in the tendon-to-bone junction along with recovering changes in the fibrocartilage zone after immunohistological tissue staining at 1, 2, 3, 6, 12, and 26 weeks postoperatively. Expression of type III collagen remained positive until 6 weeks after surgery in the double-row group, whereas it was detectable for 12 weeks in the single-row group. In both groups, type I collagen expression increased after 12 weeks. Type II collagen expression was increased after 12 weeks in the double-row versus single-row group. Clusters of chondrocytes were only visible between week 6 and 12 in the double-row group. The study demonstrates differences regarding the expression of type I and type III collagen in the tendon-to-bone junction following double-row rotator cuff repair compared to single-row repair. The healing response in this acute repair model is faster in the double-row group during the investigated healing period.

  11. Robotic-Assisted Paraesophageal Hernia Repair: Initial Experience at a Single Institution.

    PubMed

    Galvani, Carlos A; Loebl, Hannah; Osuchukwu, Obiyo; Samamé, Julia; Apel, Matthew E; Ghaderi, Iman

    2016-04-01

    Laparoscopic surgery is considered the standard approach for the treatment of paraesophageal hernias (PEHs). Despite its advantages, this approach is technically demanding with a significant learning curve. Data about the safety and utility of the robotically assisted paraesophageal hernia repair (RA-PEHR) are scarce. The aim of this study is to assess the feasibility and safety of robotic assistance for the treatment of PEH. Between June 2010 and December 2015, patients who underwent elective RA-PEHR were included in a prospectively collected database. Demographic data, American Society of Anesthesiologists (ASA) classification, preoperative testing, operative time (OT), length of hospital stay (LOS), conversion rate, morbidity, and mortality were recorded and reviewed retrospectively. Sixty-one patients underwent RA-PEHR with mesh, 72% were female (mean age of 63 and mean body mass index [BMI] of 30). ASA classification was 2.6 (57% of patients had an ASA III). With respect to the type of the hernia, the preoperative diagnosis was: Type II 26%, III 64%, and IV 13%. OT averaged 186 minutes (88-360), including robot setup time. After the 16th case, OT significantly decreased by 4.09 minutes (P = .01). There were no conversions. The average blood loss was 51 mL. Perioperative complications, including intraoperative and 30-day complications, were 6% and 23%, respectively. The mean length of hospitalization was 2.6 (1-18) days. There were no deaths. Forty patients (66%) were available for follow-up, and length of follow-up was 17 ± 15 months. Anatomic recurrence was observed in 42% of patients and only 23% of patients were symptomatic. This report represents the largest series to date of RA-PEHR. RA-PEHR has proved to be feasible and safe with a learning curve comparable to the standard laparoscopic approach.

  12. 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.

  13. A novel single pulsed electromagnetic field stimulates osteogenesis of bone marrow mesenchymal stem cells and bone repair.

    PubMed

    Fu, Yin-Chih; Lin, Chih-Chun; 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.

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

    PubMed

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

    2016-04-12

    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.

  15. 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

  16. Proteasome inhibition enhances resistance to DNA damage via upregulation of Rpn4-dependent DNA repair genes.

    PubMed

    Karpov, Dmitry S; Spasskaya, Daria S; Tutyaeva, Vera V; Mironov, Alexander S; Karpov, Vadim L

    2013-09-17

    The 26S proteasome is an ATP-dependent multi-subunit protease complex and the major regulator of intracellular protein turnover and quality control. However, its role in the DNA damage response is controversial. We addressed this question in yeast by disrupting the transcriptional regulation of the PRE1 proteasomal gene. The mutant strain has decreased proteasome activity and is hyper-resistant to various DNA-damaging agents. We found that Rpn4-target genes MAG1, RAD23, and RAD52 are overexpressed in this strain due to Rpn4 stabilisation. These genes represent three different pathways of base excision, nucleotide excision and double strand break repair by homologous recombination (DSB-HR). Consistently, the proteasome mutant displays increased DSB-HR activity. Our data imply that the proteasome may have a negative role in DNA damage response.

  17. Meningocele repair

    MedlinePlus

    ... Myelodysplasia repair; Spinal dysraphism repair; Meningomyelocele repair; Neural tube defect repair; Spina bifida repair ... If your child has hydrocephalus, a shunt (plastic tube) will be put in the child's brain to ...

  18. Three single loops enhance the biomechanical behavior of the transtibial pull-out technique for posterior meniscal root repair.

    PubMed

    Camarda, Lawrence; Pitarresi, Giuseppe; Lauria, Michele; Fazzari, Federico; D'Arienzo, Michele

    2017-07-03

    To investigate the effect of applying an additional suture to enhance the biomechanical behavior of the suture-meniscus construct used during the transtibial pull-out repair technique. A total of 20 fresh-frozen porcine tibiae with intact medial menisci were used. In one half of all specimens (N = 10), two non-absorbable sutures were passed directly over the meniscal root from the tibia side of the meniscus to the femoral side (2SS). In other ten specimens, three sutures were passed over the meniscal root (3SS). All specimens were subjected to cyclic loading followed by load-to-failure testing. Displacement of the construct was recorded at 100, 500, and 1000 cycles. Further, stiffness (500-1000 cycles) and ultimate load and modes of failure of the suture-meniscus construct were also recorded. There was no statistically significant difference between the Group 2SS and Group 3SS at the 1st (1.6 ± 0.7 vs 1.4 ± 0.4 mm) and the 100th cycle (2 ± 0.7 vs 1.8 ± 0.4 mm). At 500 and 1000 cycles, the 2SS fixation technique resulted in significantly more displacement than the 3SS fixation technique (2.8 ± 0.6 vs 2.3 ± 0.5 mm; 3.1 ± 0.7 vs 2.5 ± 0.5 mm) (p < 0.05). No differences between two groups were noted concerning ultimate load to failure and stiffness (500-1000 cycles). Three single sutures technique provided superior biomechanical properties compared with the two single sutures technique during the conducted fatigue tests. Applying three simple stitches during meniscal root repair might be beneficial for healing of the posterior meniscal root, potentially reducing the post-operative immobilization time.

  19. Early intervention effects of open repair and endovascular aortic repair on patients suffering from 40-54 mm abdominal aortic aneurysms: single center experience.

    PubMed

    Qiu, Jian; Shu, Chang; Cai, Wenwu; Li, Ming; Li, Quanming

    2017-10-01

    We conducted this study to explore the early intervention effects of open repair (OR) and endovascular aortic repair (EVAR) in treating abdominal aortic aneurysm (AAA) patients (maximum diameter 40-54 mm). We retrospectively analyzed patients under 65 years old with maximum AAA diameter 40-54 mm in our hospital from January 2010 to January 2016 (among which there are 38 EVAR cases and 18 OR cases) and compared their short mid-term operation effects. The time of the operation, bleeding volume and volume of blood transfusion during operation in the EVAR group are significantly lower than those in the OR group; differences are statistically significant (P<0.05). The operation success of the rats in both groups was 100%; the 30-day death rate was 0% and the recurrence rate was 0%; differences are not statistically significant. The total incidence rate of complications in the OR group was 22.2% while it was 5.3% in the EVAR group; differences are statistically significant (χ2=4.114, P=0.043). Early intervention (regardless of whether open or endovascular repair is used) is a feasible method for young patients with asymptomatic AAAs of 4.0 cm to 5.5 cm diameter.

  20. Treatment outcomes of single- versus double-row repair for larger than medium-sized rotator cuff tears: the effect of preoperative remnant tendon length.

    PubMed

    Kim, Young Kyu; Moon, Sung Hoon; Cho, Seung Hyun

    2013-10-01

    In rotator cuff repair, no practical guidelines exist for deciding which technique is the most beneficial to outcomes. To determine which of 2 repair techniques, the single-row (SR) and double-row suture bridge (DR-SB) methods, leads to better therapeutic outcomes in terms of remnant tendon length in patients with larger than medium-sized cuff tears. Cohort study; Level of evidence, 3. Remnant tendon length, muscle atrophy, and fatty degeneration were measured on preoperative magnetic resonance imaging (MRI) in 78 patients with larger than medium-sized rotator cuff tears who were available for follow-up MRI. There were 30 patients with remnant tendons <10 mm in length (group 1) and 48 with remnant tendons ≥10 mm in length (group 2). In group 1, the SR technique was performed on 17 patients and the DR-SB technique on 13 patients. In group 2, the SR technique was performed on 16 patients and the DR-SB technique on 32 patients. The mean follow-up period for all patients was 26.6 months (range, 24-42 months). Clinical outcomes were evaluated using the University of California, Los Angeles (UCLA), Constant, and American Shoulder and Elbow Surgeons (ASES) scores. In group 1, there was 1 retear (6%) with the SR repair and 6 (46%) with the DR-SB repair. In group 2, there were 3 retears (19%) with the SR repair and 2 (6%) with the DR-SB repair. The retear rate was significantly higher in patients with the DR-SB repair in group 1 (P = .025), while there was no significant difference between the 2 techniques in group 2 (P = .316). The UCLA and Constant scores were significantly higher in patients with the SR repair in group 1 (P = .02 and P = .029, respectively), and the UCLA and ASES scores were significantly higher in patients with the DR-SB repair in group 2 (P < .001 and P = .001, respectively). Remnant tendon length should be considered to improve repair integrity. The SR technique may provide superior rotator cuff integrity when remnant tendons are <10 mm in length.

  1. Minced Tissue in Compressed Collagen: A Cell-containing Biotransplant for Single-staged Reconstructive Repair.

    PubMed

    Chamorro, Clara I; Zeiai, Said; Reinfeldt Engberg, Gisela; Fossum, Magdalena

    2016-02-24

    Conventional techniques for cell expansion and transplantation of autologous cells for tissue engineering purposes can take place in specially equipped human cell culture facilities. These methods include isolation of cells in single cell suspension and several laborious and time-consuming events before transplantation back to the patient. Previous studies suggest that the body itself could be used as a bioreactor for cell expansion and regeneration of tissue in order to minimize ex vivo manipulations of tissues and cells before transplanting to the patient. The aim of this study was to demonstrate a method for tissue harvesting, isolation of continuous epithelium, mincing of the epithelium into small pieces and incorporating them into a three-layered biomaterial. The three-layered biomaterial then served as a delivery vehicle, to allow surgical handling, exchange of nutrition across the transplant, and a controlled degradation. The biomaterial consisted of two outer layers of collagen and a core of a mechanically stable and slowly degradable polymer. The minced epithelium was incorporated into one of the collagen layers before transplantation. By mincing the epithelial tissue into small pieces, the pieces could be spread and thereby the propagation of cells was stimulated. After the initial take of the transplants, cell expansion and reorganization would take place and extracellular matrix mature to allow ingrowth of capillaries and nerves and further maturation of the extracellular matrix. The technique minimizes ex vivo manipulations and allow cell harvesting, preparation of autograft, and transplantation to the patient as a simple one-stage intervention. In the future, tissue expansion could be initiated around a 3D mold inside the body itself, according to the specific needs of the patient. Additionally, the technique could be performed in an ordinary surgical setting without the need for sophisticated cell culturing facilities.

  2. Accumulation of True Single Strand Breaks and AP sites in Base Excision Repair Deficient Cells

    PubMed Central

    Luke, April M.; Chastain, Paul D.; Pachkowski, Brian F.; Afonin, Valeriy; Takeda, Shunichi; Kaufman, David G.; Swenberg, James A.; Nakamura, Jun

    2010-01-01

    Single strand breaks (SSBs) are one of the most frequent DNA lesions caused by endogenous and exogenous agents. The most utilized alkaline-based assays for SSB detection frequently give false positive results due to the presence of alkali-labile sites that are converted to SSBs. Methoxyamine, an acidic O-hydroxylamine, has been utilized to measure DNA damage in cells. However, the neutralization of methoxyamine is required prior to usage. Here we developed a convenient, specific SSB assay using alkaline gel electrophoresis (AGE) coupled with a neutral O-hydroxylamine, O-(tetrahydro-2H-pyran-2-yl)hydroxylamine (OTX). OTX stabilizes abasic sites (AP sites) to prevent their alkaline incision while still allowing for strong alkaline DNA denaturation. DNA from DT40 and isogenic polymerase β null cells exposed to methyl methanesulfonate were applied to the OTX-coupled AGE (OTX-AGE) assay. Time-dependent increases in SSBs were detected in each cell line with more extensive SSB formation in the null cells. These findings were supported by an assay that indirectly detects SSBs through measuring NAD(P)H depletion. An ARP-slot blot assay demonstrated a significant time-dependent increase in AP sites in both cell lines by 1 mM MMS compared to control. Furthermore, the Pol β-null cells displayed greater AP site formation than the parental DT40 cells. OTX use represents a facile approach for assessing SSB formation, whose benefits can also be applied to other established SSB assays. PMID:20851134

  3. 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

  4. Effect of Cleft Palate Repair on the Susceptibility to Contraction-Induced Injury of Single Permeabilized Muscle Fibers From Congenitally-Clefted Goat Palates

    PubMed Central

    Rader, Erik P.; Cederna, Paul S.; McClellan, William T.; Caterson, Stephanie A.; Panter, Kip E.; Yu, Deborah; Buchman, Steven R.; Larkin, Lisa M.; Faulkner, John A.; Weinzweig, Jeffrey

    2009-01-01

    Objective 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-resistant type 1 fibers. As an initial step to determining the validity of this theory, we tested the hypothesis that, in most cases, repair induces the transformation to type 1 fibers, thus diminishing susceptibility to injury. Interventions Single permeabilized levator veli palatini muscle fibers were obtained from normal palates and nonrepaired congenitally-clefted palates of young (2 months old) and adult (14 to 15 months old) goats and from repaired palates of adult goats (8 months old). Repair was done at 2 months of age using a modified von Langenbeck technique. Main Outcome Measures Fiber type was determined by contractile properties and susceptibility to injury was assessed by force deficit, the decrease in maximum force following a lengthening contraction protocol expressed as a percentage of initial force. Results For normal palates and cleft palates of young goats, the majority of the fibers were type 2 with force deficits of ~40%. Following repair, 80% of the fibers were type 1 with force deficits of 20% ± 2%; these deficits were 45% of those for nonrepaired cleft palates of adult goats (p < .0001). Conclusion The decrease in the percentage of type 2 fibers and susceptibility to injury may be important for the development of a functional levator veli palatini muscle postrepair. PMID:18333646

  5. Slab fractures of the third tarsal bone: Minimally invasive repair using a single 3.5 mm cortex screw placed in lag fashion in 17 Thoroughbred racehorses.

    PubMed

    Barker, W H J; Wright, I M

    2017-03-01

    A technique for minimally invasive repair of slab fractures of the third tarsal bone has not previously been reported. Results of third tarsal bone slab fracture repair in Thoroughbred racehorses are lacking. To report the outcomes of repair of uniplanar frontal slab factures of the third tarsal bone using a single 3.5 mm cortex screw in lag fashion. Retrospective case series. Case records of horses that had undergone this procedure were reviewed. Seventeen horses underwent surgery. Eighteen percent of cases had wedge shaped third tarsal bones. A point midway between the long and lateral digital extensor tendons and centrodistal and tarsometatarsal joints created a suitable entry site for implants. The fracture location, configuration and curvature of the third tarsal bone and associated joints requires a dorsolateral proximal-plantaromedial distal trajectory for the screw, which was determined by preplaced needles. There were no complications and fractures healed in all cases at 4-6 months post surgery. Seventy-nine percent of horses returned to racing and, at the time of reporting, 3 are in post operative rehabilitation programmes. The technique reported provides a safe, appropriate and repeatable means of repairing slab fractures of the third tarsal bone. Surgical repair is a viable alternative to conservative management. © 2016 EVJ Ltd.

  6. Ultrasound evaluation of arthroscopic full-thickness supraspinatus rotator cuff repair: single-row versus double-row suture bridge (transosseous equivalent) fixation. Results of a prospective, randomized study.

    PubMed

    Gartsman, Gary M; Drake, Gregory; Edwards, T Bradley; Elkousy, Hussein A; Hammerman, Steven M; O'Connor, Daniel P; Press, Cyrus M

    2013-11-01

    The purpose of this study was to compare the structural outcomes of a single-row rotator cuff repair and double-row suture bridge fixation after arthroscopic repair of a full-thickness supraspinatus rotator cuff tear. We evaluated with diagnostic ultrasound a consecutive series of ninety shoulders in ninety patients with full-thickness supraspinatus tears at an average of 10 months (range, 6-12) after operation. A single surgeon at a single hospital performed the repairs. Inclusion criteria were full-thickness supraspinatus tears less than 25 mm in their anterior to posterior dimension. Exclusion criteria were prior operations on the shoulder, partial thickness tears, subscapularis tears, infraspinatus tears, combined supraspinatus and infraspinatus repairs and irreparable supraspinatus tears. Forty-three shoulders were repaired with single-row technique and 47 shoulders with double-row suture bridge technique. Postoperative rehabilitation was identical for both groups. Ultrasound criteria for healed repair included visualization of a tendon with normal thickness and length, and a negative compression test. Eighty-three patients were available for ultrasound examination (40 single-row and 43 suture-bridge). Thirty of 40 patients (75%) with single-row repair demonstrated a healed rotator cuff repair compared to 40/43 (93%) patients with suture-bridge repair (P = .024). Arthroscopic double-row suture bridge repair (transosseous equivalent) of an isolated supraspinatus rotator cuff tear resulted in a significantly higher tendon healing rate (as determined by ultrasound examination) when compared to arthroscopic single-row repair. Copyright © 2013 Journal of Shoulder and Elbow Surgery Board of Trustees. Published by Mosby, Inc. All rights reserved.

  7. Modern management of traumatic subclavian artery injuries: a single institution's experience in the evolution of endovascular repair.

    PubMed

    Carrick, Matthew M; Morrison, C Anne; Pham, Hoang Q; Norman, Michael A; Marvin, Blake; Lee, Jeffery; Wall, Matthew J; Mattox, Kenneth L

    2010-01-01

    Subclavian artery injuries traditionally require morbid surgical procedures. Repair by way of an endovascular approach can potentially decrease the morbidity and mortality associated with these injuries. A 2-year retrospective review of trauma patients with subclavian artery injuries was performed at our institution. Relevant data were extracted from patient records and analyzed. These results were then used to develop an algorithm for the management of trauma patients with subclavian artery injuries. Fifteen patients with subclavian artery injuries were identified. Five patients died in the emergency room. Of the 10 surviving patients, 8 had their diagnosis made at arteriogram. Six patients underwent endovascular repair, and 4 of these repairs were successful. Three patients were managed by way of open repair. Two deaths occurred in the endovascular group, and 1 death occurred in the open group. Our findings suggest that endovascular management of subclavian artery injuries is an acceptable technique in appropriate candidates and compares favorably with open repair. However, as with open repair, the associated morbidity and mortality remains quite high. We propose an algorithm whereby hemodynamically stable patients with hard signs of vascular injury proceed directly to angiography, whereas open repair is reserved for those patients who are unstable or in whom a catheter-based approach has previously failed.

  8. Nej1 recruits the Srs2 helicase to DNA double-strand breaks and supports repair by a single-strand annealing-like mechanism.

    PubMed

    Carter, Sidney D; Vigasová, Dana; Chen, Jiang; Chovanec, Miroslav; Aström, Stefan U

    2009-07-21

    Double-strand breaks (DSBs) represent the most severe DNA lesion a cell can suffer, as they pose the risk of inducing loss of genomic integrity and promote oncogenesis in mammals. Two pathways repair DSBs, nonhomologous end joining (NHEJ) and homologous recombination (HR). With respect to mechanism and genetic requirements, characterization of these pathways has revealed a large degree of functional separation between the two. Nej1 is a cell-type specific regulator essential to NHEJ in Saccharomyces cerevisiae. Srs2 is a DNA helicase with multiple roles in HR. In this study, we show that Nej1 physically interacts with Srs2. Furthermore, mutational analysis of Nej1 suggests that the interaction was strengthened by Dun1-dependent phosphorylation of Nej1 serines 297/298. Srs2 was previously shown to be recruited to replication forks, where it promotes translesion DNA synthesis. We demonstrate that Srs2 was also efficiently recruited to DSBs generated by the HO endonuclease. Additionally, efficient Srs2 recruitment to this DSB was dependent on Nej1, but independent of mechanisms facilitating Srs2 recruitment to replication forks. Functionally, both Nej1 and Srs2 were required for efficient repair of DSBs with 15-bp overhangs, a repair event reminiscent of a specific type of HR called single-strand annealing (SSA). Moreover, absence of Rad51 suppressed the SSA-defect in srs2 and nej1 strains. We suggest a model in which Nej1 recruits Srs2 to DSBs to promote NHEJ/SSA-like repair by dismantling inappropriately formed Rad51 nucleoprotein filaments. This unexpected link between NHEJ and HR components may represent cross-talk between DSB repair pathways to ensure efficient repair.

  9. Nej1 recruits the Srs2 helicase to DNA double-strand breaks and supports repair by a single-strand annealing-like mechanism

    PubMed Central

    Carter, Sidney D.; Vigašová, Dana; Chen, Jiang; Chovanec, Miroslav; Åström, Stefan U.

    2009-01-01

    Double-strand breaks (DSBs) represent the most severe DNA lesion a cell can suffer, as they pose the risk of inducing loss of genomic integrity and promote oncogenesis in mammals. Two pathways repair DSBs, nonhomologous end joining (NHEJ) and homologous recombination (HR). With respect to mechanism and genetic requirements, characterization of these pathways has revealed a large degree of functional separation between the two. Nej1 is a cell-type specific regulator essential to NHEJ in Saccharomyces cerevisiae. Srs2 is a DNA helicase with multiple roles in HR. In this study, we show that Nej1 physically interacts with Srs2. Furthermore, mutational analysis of Nej1 suggests that the interaction was strengthened by Dun1-dependent phosphorylation of Nej1 serines 297/298. Srs2 was previously shown to be recruited to replication forks, where it promotes translesion DNA synthesis. We demonstrate that Srs2 was also efficiently recruited to DSBs generated by the HO endonuclease. Additionally, efficient Srs2 recruitment to this DSB was dependent on Nej1, but independent of mechanisms facilitating Srs2 recruitment to replication forks. Functionally, both Nej1 and Srs2 were required for efficient repair of DSBs with 15-bp overhangs, a repair event reminiscent of a specific type of HR called single-strand annealing (SSA). Moreover, absence of Rad51 suppressed the SSA-defect in srs2 and nej1 strains. We suggest a model in which Nej1 recruits Srs2 to DSBs to promote NHEJ/SSA-like repair by dismantling inappropriately formed Rad51 nucleoprotein filaments. This unexpected link between NHEJ and HR components may represent cross-talk between DSB repair pathways to ensure efficient repair. PMID:19571008

  10. Two-stage hypospadias repair with a free graft for severe primary and revision hypospadias: A single surgeon's experience with long-term follow-up.

    PubMed

    Pfistermüller, K L M; Manoharan, S; Desai, D; Cuckow, P M

    2017-02-01

    Repair of severe primary and revision hypospadias is a demanding procedure. Debate continues as to whether a two-stage approach or single-stage technique is superior. The two-stage procedure with a free graft involves penile straightening followed by application of a graft for the neourethral plate at stage one; with tubularization at stage two after graft maturation. To report the outcomes of a single surgeon's experience with the two-stage repair using a free graft for both severe primary and revision hypospadias with long-term follow-up. Between July 1998 and January 2010, 301 boys underwent a two-stage reconstruction. The surgical technique is described in the manuscript. Primary repairs (n = 208): indications for a two-stage approach with a free graft included meatal position, presence of corporal chordee, and poor glans development. Median follow-up from completion of the second stage was 75 months. Revision repairs (n = 93): indications included urethral fistula, excessive scarring/meatal stenosis, balanitis xerotica obliterans (BXO), and residual or untreated chordee. Median follow-up from completion of the second stage was 85 months. For the primary repairs (n = 208), the graft took well in all but one case. Second-stage complications included fistula (7), meatal stenosis (3), partial glans dehiscence (3), and all were re-operated (13). For the revision repairs (n = 93), the graft took well in all but four cases. Second-stage complications included fistula (5), meatal stenosis (3), breakdown (1) and reoperation (8). In a systematic review of 20 years of publications on the repair of primary severe hypospadias, the two-stage procedure with a free graft demonstrated an overall complication rate of 22%; this was a distinct overall benefit when compared with the single-stage procedures in terms of lower complication rates (Castagnetti and El-Ghoneimi, 2010). Our results for the severe primary repairs revealed significantly lower complication rates than

  11. Insertional Mutagenesis by CRISPR/Cas9 Ribonucleoprotein Gene Editing in Cells Targeted for Point Mutation Repair Directed by Short Single-Stranded DNA Oligonucleotides.

    PubMed

    Rivera-Torres, Natalia; Banas, Kelly; Bialk, Pawel; Bloh, Kevin M; Kmiec, Eric B

    2017-01-01

    CRISPR/Cas9 and single-stranded DNA oligonucleotides (ssODNs) have been used to direct the repair of a single base mutation in human genes. Here, we examine a method designed to increase the precision of RNA guided genome editing in human cells by utilizing a CRISPR/Cas9 ribonucleoprotein (RNP) complex to initiate DNA cleavage. The RNP is assembled in vitro and induces a double stranded break at a specific site surrounding the mutant base designated for correction by the ssODN. We use an integrated mutant eGFP gene, bearing a single base change rendering the expressed protein nonfunctional, as a single copy target in HCT 116 cells. We observe significant gene correction activity of the mutant base, promoted by the RNP and single-stranded DNA oligonucleotide with validation through genotypic and phenotypic readout. We demonstrate that all individual components must be present to obtain successful gene editing. Importantly, we examine the genotype of individually sorted corrected and uncorrected clonally expanded cell populations for the mutagenic footprint left by the action of these gene editing tools. While the DNA sequence of the corrected population is exact with no adjacent sequence modification, the uncorrected population exhibits heterogeneous mutagenicity with a wide variety of deletions and insertions surrounding the target site. We designate this type of DNA aberration as on-site mutagenicity. Analyses of two clonal populations bearing specific DNA insertions surrounding the target site, indicate that point mutation repair has occurred at the level of the gene. The phenotype, however, is not rescued because a section of the single-stranded oligonucleotide has been inserted altering the reading frame and generating truncated proteins. These data illustrate the importance of analysing mutagenicity in uncorrected cells. Our results also form the basis of a simple model for point mutation repair directed by a short single-stranded DNA oligonucleotides and

  12. Insertional Mutagenesis by CRISPR/Cas9 Ribonucleoprotein Gene Editing in Cells Targeted for Point Mutation Repair Directed by Short Single-Stranded DNA Oligonucleotides

    PubMed Central

    Rivera-Torres, Natalia; Bialk, Pawel; Bloh, Kevin M.; Kmiec, Eric B.

    2017-01-01

    CRISPR/Cas9 and single-stranded DNA oligonucleotides (ssODNs) have been used to direct the repair of a single base mutation in human genes. Here, we examine a method designed to increase the precision of RNA guided genome editing in human cells by utilizing a CRISPR/Cas9 ribonucleoprotein (RNP) complex to initiate DNA cleavage. The RNP is assembled in vitro and induces a double stranded break at a specific site surrounding the mutant base designated for correction by the ssODN. We use an integrated mutant eGFP gene, bearing a single base change rendering the expressed protein nonfunctional, as a single copy target in HCT 116 cells. We observe significant gene correction activity of the mutant base, promoted by the RNP and single-stranded DNA oligonucleotide with validation through genotypic and phenotypic readout. We demonstrate that all individual components must be present to obtain successful gene editing. Importantly, we examine the genotype of individually sorted corrected and uncorrected clonally expanded cell populations for the mutagenic footprint left by the action of these gene editing tools. While the DNA sequence of the corrected population is exact with no adjacent sequence modification, the uncorrected population exhibits heterogeneous mutagenicity with a wide variety of deletions and insertions surrounding the target site. We designate this type of DNA aberration as on-site mutagenicity. Analyses of two clonal populations bearing specific DNA insertions surrounding the target site, indicate that point mutation repair has occurred at the level of the gene. The phenotype, however, is not rescued because a section of the single-stranded oligonucleotide has been inserted altering the reading frame and generating truncated proteins. These data illustrate the importance of analysing mutagenicity in uncorrected cells. Our results also form the basis of a simple model for point mutation repair directed by a short single-stranded DNA oligonucleotides and

  13. A biomechanical comparison of tendon-bone interface motion and cyclic loading between single-row, triple-loaded cuff repairs and double-row, suture-tape cuff repairs using biocomposite anchors.

    PubMed

    Barber, F Alan; Drew, Otis R

    2012-09-01

    To compare tendon-bone interface motion and cyclic loading in a single-row, triple-loaded anchor repair with a suture-tape, rip-stop, double-row rotator cuff repair. Using 18 human shoulders from 9 matched cadaveric pairs, we created 2 groups of rotator cuff repairs. Group 1 was a double-row, rip-stop, suture-tape construct. Group 2 was a single-row, triple-loaded construct. Before mechanical testing, the supraspinatus footprint was measured with calipers. A superiorly positioned digital camera optically measured the tendon footprint motion during 60° of humeral internal and external rotation. Specimens were secured at a fixed angle not exceeding 45° in reference to the load. After preloading, each sample was cycled between 10 N and 100 N for 200 cycles at 1 Hz, followed by destructive testing at 33 mm/s. A digital camera with tracking software measured the repair displacement at 100 and 200 cycles. Ultimate load and failure mode for each sample were recorded. The exposed anterior footprint border (6.5% ± 6%) and posterior footprint border (0.9% ± 1.7%) in group 1 were statistically less than the exposed anterior footprint border (30.3% ± 17%) and posterior footprint border (29.8% ± 14%) in group 2 (P = .003 and P < .001, respectively). The maximal internal rotation and external rotation tendon footprint displacements in group 1 (1.6 mm and 1.4 mm, respectively) were less than those in group 2 (both 3.6 mm) (P = .007 and P = .004, respectively). Mean displacement after 100 cycles for group 1 and group 2 was 2.0 mm and 3.2 mm, respectively, and at 200 cycles, mean displacement was 2.5 mm and 4.2 mm, respectively (P = .02). The mean ultimate failure load in group 1 (586 N) was greater than that in group 2 (393 N) (P = .02). The suture-tendon interface was the site of most construct failures. The suture-tape, rip-stop, double-row rotator cuff repair had greater footprint coverage, less rotational footprint displacement, and a greater mean ultimate failure load

  14. 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

  15. Laparoscopic Repair of Incisional Hernia Following Liver Transplantation-Early Experience of a Single Institution in Taiwan.

    PubMed

    Kuo, S-C; Lin, C-C; Elsarawy, A; Lin, Y-H; Wang, S-H; Wu, Y-J; Chen, C-L

    2017-10-01

    Ventral incisional hernia (VIH) is not uncommon following liver transplantation. Open repair was traditionally adopted for its management. Laparoscopic repair of VIH has been performed successfully in nontransplant patients with evidence of reduced recurrence rates and hospital stay. However, the application of VIH in post-transplantation patients has not been well established. Herein, we provide our initial experience with laparoscopic repair of post-transplantation VIH. From March 2015 to March 2016, 18 cases of post-transplantation VIH were subjected to laparoscopic repair (laparoscopy group). A historical control group of 17 patients who underwent conventional open repair (open group) from January 2013 to January 2015 were identified for comparison. The demographics and clinical outcomes were retrospectively compared. There were no significant differences among basic demographics between the 2 groups. No conversion was recorded in the laparoscopy group. Recurrence of VIH up to the end of the study period was not noted. In the laparoscopy group, the minor complications were lower (16.7% vs 52.9%; P = .035), the length of hospital stay was shorter (3 d vs 7 d, P = .007), but the median operative time was longer (137.5 min vs 106 min; P = .003). Laparoscopic repair of post-transplantation VIH is a safe and feasible procedure with shorter length of hospital stay. Copyright © 2017 Elsevier Inc. All rights reserved.

  16. Imperfect DNA lesion repair in the semiconservative quasispecies model: Derivation of the Hamming class equations and solution of the single-fitness peak landscape

    NASA Astrophysics Data System (ADS)

    Tannenbaum, Emmanuel; Sherley, James L.; Shakhnovich, Eugene I.

    2004-12-01

    This paper develops a Hamming class formalism for the semiconservative quasispecies equations with imperfect lesion repair, first presented and analytically solved in Y. Brumer and E.I. Shakhnovich (q-bio.GN/0403018, 2004). Starting from the quasispecies dynamics over the space of genomes, we derive an equivalent dynamics over the space of ordered sequence pairs. From this set of equations, we are able to derive the infinite sequence length form of the dynamics for a class of fitness landscapes defined by a master genome. We use these equations to solve for a generalized single-fitness-peak landscape, where the master genome can sustain a maximum number of lesions and remain viable. We determine the mean equilibrium fitness and error threshold for this class of landscapes, and show that when lesion repair is imperfect, semiconservative replication displays characteristics from both conservative replication and semiconservative replication with perfect lesion repair. The work presented here provides a formulation of the model which greatly facilitates the analysis of a relatively broad class of fitness landscapes, and thus serves as a convenient springboard into biological applications of imperfect lesion repair.

  17. APE1 overexpression in XRCC1-deficient cells complements the defective repair of oxidative single strand breaks but increases genomic instability

    PubMed Central

    Sossou, Marguerite; Flohr-Beckhaus, Claudia; Schulz, Ina; Daboussi, Fayza; Epe, Bernd; Radicella, J. Pablo

    2005-01-01

    XRCC1 protein is essential for mammalian viability and is required for the efficient repair of single strand breaks (SSBs) and damaged bases in DNA. XRCC1-deficient cells are genetically unstable and sensitive to DNA damaging agents. XRCC1 has no known enzymatic activity and is thought to act as a scaffold protein for both SSB and base excision repair activities. To further define the defects leading to genetic instability in XRCC1-deficient cells, we overexpressed the AP endonuclease APE1, shown previously to interact with and be stimulated by XRCC1. Here, we report that the overexpression of APE1 can compensate for the impaired capability of XRCC1-deficient cells to repair SSBs induced by oxidative DNA damage, both in vivo and in whole-cell extracts. We show that, for this kind of damage, the repair of blocked DNA ends is rate limiting and can be performed by APE1. Conversely, APE1 overproduction resulted in a 3-fold increase in the sensitivity of XRCC1-deficient cells to an alkylating agent, most probably due to the accumulation of SSBs. Finally, the overproduction of APE1 results in increases of 40% in the frequency of micronuclei and 33% in sister chromatid exchanges of XRCC1− cells. These data suggest that the spontaneous generation of AP sites could be at the origin of the SSBs responsible for the spontaneous genetic instability characteristic of XRCC1-deficient cells. PMID:15647512

  18. Human Longevity and Variation in GH/IGF-1/Insulin Signaling, DNA Damage Signaling and Repair and Pro/antioxidant Pathway Genes: Cross Sectional and Longitudinal Studies

    PubMed Central

    Soerensen, Mette; Dato, Serena; Tan, Qihua; Thinggaard, Mikael; Kleindorp, Rabea; Beekman, Marian; Jacobsen, Rune; Suchiman, H. Eka D.; de Craen, Anton J.M.; Westendorp, Rudi G.J.; Schreiber, Stefan; Stevnsner, Tinna; Bohr, Vilhelm A.; Slagboom, P. Eline; Nebel, Almut; Vaupel, James W.; Christensen, Kaare; McGue, Matt; Christiansen, Lene

    2012-01-01

    Here we explore association with human longevity of common genetic variation in three major candidate pathways: GH/IGF-1/insulin signaling, DNA damage signaling and repair and pro/antioxidants by investigating 1273 tagging SNPs in 148 genes composing these pathways. In a case-control study of 1089 oldest-old (age 92–93) and 736 middle-aged Danes we found 1 pro/antioxidant SNP (rs1002149 (GSR)), 5 GH/IGF-1/INS SNPs (rs1207362 (KL), rs2267723 (GHRHR), rs3842755 (INS), rs572169 (GHSR), rs9456497 (IGF2R)) and 5 DNA repair SNPs (rs11571461 (RAD52), rs13251813 (WRN), rs1805329 (RAD23B), rs2953983 (POLB), rs3211994 (NTLH1)) to be associated with longevity after correction for multiple testing. In a longitudinal study with 11 years of follow-up on survival in the oldest-old Danes we found 2 pro/antioxidant SNPs (rs10047589 (TNXRD1), rs207444 (XDH)), 1 GH/IGF-1/INS SNP (rs26802 (GHRL)) and 3 DNA repair SNPs (rs13320360 (MLH1), rs2509049 (H2AFX) and rs705649 (XRCC5)) to be associated with mortality in late life after correction for multiple testing. When examining the 11 SNPs from the case-control study in the longitudinal data, rs3842755 (INS), rs13251813 (WRN) and rs3211994 (NTHL1) demonstrated the same directions of effect (p<0.05), while rs9456497 (IGF2R) and rs1157146 (RAD52) showed non-significant tendencies, indicative of effects also in late life survival. In addition, rs207444 (XDH) presented the same direction of effect when inspecting the 6 SNPs from the longitudinal study in the case-control data, hence, suggesting an effect also in survival from middle age to old age. No formal replications were observed when investigating the 11 SNPs from the case-control study in 1613 oldest-old (age 95–110) and 1104 middle-aged Germans, although rs11571461 (RAD52) did show a supportive non-significant tendency (OR = 1.162, 95% CI = 0.927–1.457). The same was true for rs10047589 (TNXRD1) (HR = 0.758, 95%CI = 0.543–1.058) when examining the 6 SNPs from the longitudinal

  19. Single-stranded DNA oligomers stimulate error-prone alternative repair of DNA double-strand breaks through hijacking Ku protein

    PubMed Central

    Yuan, Ying; Britton, Sébastien; Delteil, Christine; Coates, Julia; Jackson, Stephen P.; Barboule, Nadia; Frit, Philippe; Calsou, Patrick

    2015-01-01

    In humans, DNA double-strand breaks (DSBs) are repaired by two mutually-exclusive mechanisms, homologous recombination or end-joining. Among end-joining mechanisms, the main process is classical non-homologous end-joining (C-NHEJ) which relies on Ku binding to DNA ends and DNA Ligase IV (Lig4)-mediated ligation. Mostly under Ku- or Lig4-defective conditions, an alternative end-joining process (A-EJ) can operate and exhibits a trend toward microhomology usage at the break junction. Homologous recombination relies on an initial MRN-dependent nucleolytic degradation of one strand at DNA ends. This process, named DNA resection generates 3′ single-stranded tails necessary for homologous pairing with the sister chromatid. While it is believed from the current literature that the balance between joining and recombination processes at DSBs ends is mainly dependent on the initiation of resection, it has also been shown that MRN activity can generate short single-stranded DNA oligonucleotides (ssO) that may also be implicated in repair regulation. Here, we evaluate the effect of ssO on end-joining at DSB sites both in vitro and in cells. We report that under both conditions, ssO inhibit C-NHEJ through binding to Ku and favor repair by the Lig4-independent microhomology-mediated A-EJ process. PMID:26350212

  20. INO80 and gamma-H2AX interaction links ATP-dependent chromatin remodeling to DNA damage repair.

    PubMed

    Morrison, Ashby J; Highland, Jessica; Krogan, Nevan J; Arbel-Eden, Ayelet; Greenblatt, Jack F; Haber, James E; Shen, Xuetong

    2004-12-17

    While the role of ATP-dependent chromatin remodeling in transcription is well established, a link between chromatin remodeling and DNA repair has remained elusive. We have found that the evolutionarily conserved INO80 chromatin remodeling complex directly participates in the repair of a double-strand break (DSB) in yeast. The INO80 complex is recruited to a HO endonuclease-induced DSB through a specific interaction with the DNA damage-induced phosphorylated histone H2A (gamma-H2AX). This interaction requires Nhp10, an HMG-like subunit of the INO80 complex. The loss of Nhp10 or gamma-H2AX results in reduced INO80 recruitment to the DSB. Finally, components of the INO80 complex show synthetic genetic interactions with the RAD52 DNA repair pathway, the main pathway for DSB repair in yeast. Our findings reveal a new role of ATP-dependent chromatin remodeling in nuclear processes and suggest that an ATP-dependent chromatin remodeling complex can read a DNA repair histone code.

  1. Polylactide-caprolactone composite mesh used for ventral hernia repair: a prospective, randomized, single-blind controlled trial.

    PubMed

    Shen, Ying-Mo; Li, Qi; Chen, Jie; Sun, Li; Chen, Fu-Qiang

    2017-02-23

    Although composite surgical meshes are widely used in laparoscopic repair of ventral hernia, the risk of postoperative complications associated with these type of mesh is relatively high. In this report, we demonstrated the safety as well as the effectiveness of a new composite polypropylene mesh coated with poly Llactidecocaprolactone ε (EasyProsthesTM) for the repair of ventral hernia. This study was a randomized, controlled trial designed to compare EasyProsthes composite mesh (EPM) with ParietexTM Composite (PCO) in patients undergoing laparoscopic ventral hernia repair. Hernia recurrence, chronic pain, seroma formation, intestinal fistula or obstruction, wound or abdominal infection, and viscera adhesion were evaluated. 80 patients who needed repair surgery for primary or secondary ventral hernias were enrolled in this study. Patients were divided into two groups: the EPM group (n=40) and the PCO group (n=40). Patients completed 12 months of followup. Our results revealed that one patient in the EPM group (2.5%) and two patients in the PCO group (5%) developed mesh viscera adhesions after surgery (p=1.000). We had no case of intestinal fistulas or obstruction. Seventeen patients in EPM group (42.5%) and 21 in PCO group (52.2%) developed post surgical seromas in the surgery area (p=0.370). One patient from each group developed postoperative wound infection. There was no case of abdominal infection, chronic pain or hernia recurrence. The incidence of postoperative complications in the EPM group was similar to that observed in the PCO group. We concluded that EPM is a safe and effective method to be used in ventral hernia repair surgeries.

  2. Vertical versus horizontal suture configuration for the repair of isolated type II SLAP lesion through a single anterior portal: a randomized controlled trial.

    PubMed

    Silberberg, Jose María; Moya-Angeler, Joaquín; Martín, Eulogio; Leyes, Manuel; Forriol, Francisco

    2011-12-01

    To compare the clinical and functional outcomes of the repair of an isolated type II SLAP lesion by 2 different configuration techniques (vertical v horizontal suture) through a single anterior portal. We designed a prospective, double-blinded, randomized clinical trial. A junior orthopaedic surgeon, who made the initial diagnosis, used a 10-point visual analog scale for pain and subjective instability and the American Shoulder and Elbow Surgeons (ASES) scoring system and evaluated the range of motion. After a diagnostic arthroscopy that ascertained the presence of an isolated type II SLAP lesion, patients were randomized to receive either vertical suture configuration (group 1) or horizontal suture configuration (group 2), both through a single anterior portal. Thirty-two patients were included in the study. The mean follow-up time was 37 months. The mean postoperative ASES score was 91.9 in group 1 versus 95.8 in group 2 (P > .05). The differences observed from preoperative ASES score for both groups to postoperative ASES score were statistically significant. The differences observed in preoperative range of motion from the contralateral healthy shoulder and the affected shoulder in both groups were all clinically and statistically significant. Comparing the overall range of motion of the affected limb postoperatively with the range of motion of the contralateral healthy shoulder and between both groups, we found no statistically significant differences in forward flexion (P = .067), external rotation (P = .101), or internal rotation (P = .343). The results of this study suggest that the repair of an isolated type II SLAP lesion through a single anterior portal is clinically and functionally beneficial to patients regardless of the suture configuration performed (vertical or horizontal suture) because no differences were observed between these configurations after repair of an isolated type II SLAP lesion. Level I, randomized controlled trial. Copyright © 2011

  3. Novel single-loop and double-loop knot stitch in comparison with the modified Mason-Allen stitch for rotator cuff repair.

    PubMed

    Frosch, Stephan; Buchhorn, Gottfried; Hoffmann, Anja; Balcarek, Peter; Schüttrumpf, Jan Philipp; August, Florian; Stürmer, Klaus Michael; Walde, Hans Joachim; Walde, Tim Alexander

    2015-05-01

    In rotator cuff repair, strong and long-lasting suturing techniques that do not require additional implants are needed. This study examines the ultimate load to failure and the Young's modulus at the suture-tendon interface for a novel single-loop knot stitch and double-loop knot stitch. These values are compared to those of the modified Mason-Allen stitch. Twenty-four infraspinatus muscles with tendons were dissected from porcine shoulders (twelve Goettingen minipigs). The preparations were randomly allocated to three groups of eight samples. Load-to-failure testing of the single-loop knot stitch, the double-loop knot stitch and the mMAS were performed using a Zwick 1446 universal testing machine (Zwick-Roell AG, Ulm, Germany). The highest ultimate load to failure for the three techniques occurred with the double-loop knot stitch with a median value of 382.2 N (range 291.8-454.2 N). These values were significantly higher than those of the single-loop knot stitch, which had a median value of 259.5 N (range 139.6-366.3 N) and the modified Mason-Allen stitch, which had a median value of 309.3 N (range 84.55-382.9 N). The values of the single-loop knot stitch and the modified Mason-Allen stitch did not differ significantly. Regarding the Young's modulus, no significant differences were found between the double-loop knot stitch with a median value of 496.02 N/mm² (range 400.4-572.6 N/mm²) and the modified Mason-Allen stitch with 498.5 N/mm² (range 375.5-749.2 N/mm²) with respect to the stiffness of the suture-tendon complex. The median value for the Young's modulus of the single-loop knot stitch of 392.1 N/mm² (range 285.7-510.6 N/mm²) was significantly lower than those of the double-loop knot stitch and modified Mason-Allen stitch. This in vitro animal study demonstrated that both the single-loop knot stitch and the double-loop knot stitch have excellent ultimate load-to-failure properties when used for rotator cuff repair. The introduced single-loop knot stitch

  4. 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.

  5. 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

    Yamane, Yoshitaka; 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."

  6. 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

  7. The phosphatase activity of mammalian polynucleotide kinase takes precedence over its kinase activity in repair of single strand breaks.

    PubMed

    Dobson, Caroline J; Allinson, Sarah L

    2006-01-01

    The dual function mammalian DNA repair enzyme, polynucleotide kinase (PNK), facilitates strand break repair through catalysis of 5'-hydroxyl phosphorylation and 3'-phosphate dephosphorylation. We have examined the relative activities of the kinase and phosphatase functions of PNK using a novel assay, which allows the simultaneous characterization of both activities in processing nicks and gaps containing both 3'-phosphate and 5'-hydroxyl. Under multiple turnover conditions the phosphatase activity of the purified enzyme is significantly more active than its kinase activity. Consistent with this result, phosphorylation of the 5'-hydroxyl is rate limiting in cell extract mediated-repair of a nicked substrate. On characterizing the effects of individually mutating the two active sites of PNK we find that while site-directed mutagenesis of the kinase domain of PNK does not affect its phosphatase activity, disruption of the phosphatase domain also abrogates kinase function. This loss of kinase function requires the presence of a 3'-phosphate, but it need not be present in the same strand break as the 5'-hydroxyl. PNK preferentially binds 3'-phosphorylated substrates and DNA binding to the phosphatase domain blocks further DNA binding by the kinase domain.

  8. Phototriggered formation and repair of DNA containing a site-specific single strand break of the type produced by ionizing radiation or AP lyase activity.

    PubMed

    Zhang, K; Taylor, J S

    2001-01-09

    DNA strand breaks are produced by a variety of agents and processes such as ionizing radiation, xenobiotics, oxidative metabolism, and enzymatic processing of DNA base damage. One of the major types of strand breaks produced by these processes is a single nucleotide gap terminating in 5'- and 3'-phosphates. Previously, we had developed a method for sequence-specifically producing such phosphate-terminated strand breaks in an oligodeoxynucleotide by way of two photochemically activated (caged) building blocks placed in tandem. We now report the design and synthesis of a single caged building block consisting of 1,3-(2-nitrophenyl)-1,3-propanediol, for producing phosphate-terminated strand breaks, and its use producing such a break at a specific site in a double-stranded circular DNA vector. To produce the site-specific break in a duplex vector, a primer containing the caged single strand break was extended opposite the single strand form of a circular DNA vector followed by enzymatic ligation and purification. The single strand break could then be formed in quantitative yield by irradiation of the vector with 365 nm light. In contrast to a previous study, it was found that the strand break can be repaired by Escherichia coli DNA polymerase I and E. coli DNA ligase alone, though less efficiently than in the presence of the 3'-phosphate processing enzyme E. coli endonuclease IV. Repair in the absence of endonuclease IV could be attributed to hydrolysis of the 3'-phosphate in the presence of dNTP and to a lesser extent to exonucleolytic removal of the 3'-phosphate-bearing terminal nucleotide by way of the 3' --> 5' exonuclease activity of polymerase I. This work demonstrates that specialized 3'-end processing enzymes such as endonuclease IV or exonuclease III are not absolutely required for repair of phosphate-terminated gaps. In addition to preparing single strand breaks, the caged building block described should also be useful for preparing double strand breaks and

  9. Single-stage cartilage repair in the knee with microfracture covered with a resorbable polymer-based matrix and autologous bone marrow concentrate.

    PubMed

    Enea, D; Cecconi, S; Calcagno, S; Busilacchi, A; Manzotti, S; Kaps, C; Gigante, A

    2013-12-01

    Different single-stage surgical approaches are currently under evaluation to repair focal cartilage lesions. This study aims to analyze the clinical and histological results after treatment of focal condylar articular lesions of the knee with microfracture and subsequent covering with a resorbable polyglycolic acid/hyaluronan (PGA -HA) matrix augmented with autologous bone marrow concentrate (BMC). Nine patients with focal lesions of the condylar articular cartilage were consecutively treated with arthroscopic PGA -HA-covered microfracture and bone marrow concentrate (PGA -HA-CMBMC). Patients were retrospectively assessed using standardized assessment tools and magnetic resonance imaging (MRI). Five patients consented to undergo second look arthroscopy and 2 consented biopsy harvest. All the patients but one showed improvement in clinical scoring from the pre-operative situation to the latest follow-up (average 22±2months). The mean IKDC subjective score, Lysholm score, VAS and the median Tegner score significantly increased from baseline to the latest follow-up. Cartilage macroscopic assessment at 12months revealed that one repair appeared normal, three almost normal and one appeared abnormal. Histological analysis proofed hyaline-like cartilage repair tissue formation in one case. MRI at 8 to 12months follow-up showed complete defect filling. The first clinical experience with single-stage treatment of focal cartilage defects of the knee with microfracture and covering with the PGA -HA matrix augmented with autologous BMC (PGA -HA-CMBMC) suggests that it is safe, it improves knee function and has the potential to regenerate hyaline-like cartilage. IV, case series. Copyright © 2013 Elsevier B.V. All rights reserved.

  10. Defective DNA strand break repair after DNA damage in prostate cancer cells: implications for genetic instability and prostate cancer progression.

    PubMed

    Fan, Rong; Kumaravel, Tirukalikundram S; Jalali, Farid; Marrano, Paula; Squire, Jeremy A; Bristow, Robert G

    2004-12-01

    Together with cell cycle checkpoint control, DNA repair plays a pivotal role in protecting the genome from endogenous and exogenous DNA damage. Although increased genetic instability has been associated with prostate cancer progression, the relative role of DNA double-strand break repair in malignant versus normal prostate epithelial cells is not known. In this study, we determined the RNA and protein expression of a series of DNA double-strand break repair genes in both normal (PrEC-epithelial and PrSC-stromal) and malignant (LNCaP, DU-145, and PC-3) prostate cultures. Expression of genes downstream of ATM after ionizing radiation-induced DNA damage reflected the p53 status of the cell lines. In the malignant prostate cell lines, mRNA and protein levels of the Rad51, Xrcc3, Rad52, and Rad54 genes involved in homologous recombination were elevated approximately 2- to 5-fold in comparison to normal PrEC cells. The XRCC1, DNA polymerase-beta and -delta proteins were also elevated. There were no consistent differences in gene expression relating to the nonhomologous end-joining pathway. Despite increased expression of DNA repair genes, malignant prostate cancer cells had defective repair of DNA breaks, alkali-labile sites, and oxidative base damage. Furthermore, after ionizing radiation and mitomycin C treatment, chromosomal aberration assays confirmed that malignant prostate cells had defective DNA repair. This discordance between expression and function of DNA repair genes in malignant prostate cancer cells supports the hypothesis that prostate tumor progression may reflect aberrant DNA repair. Our findings support the development of novel treatment strategies designed to reinstate normal DNA repair in prostate cancer cells.

  11. Epidermal p53 response and repair of thymine dimers in human skin after a single dose of ultraviolet radiation: effects of photoprotection.

    PubMed

    Ling, G; Chadwick, C A; Berne, B; Potten, C S; Pontén, J; Pontén, F

    2001-05-01

    A cellular p53 response, DNA repair enzymes and melanin pigmentation are important strategies utilized by skin keratinocytes against impairment caused by ultraviolet radiation (UVR). In this study a double-immunofluorescence technique was used to investigate UVR-induced thymine dimers and p53 protein simultaneously. Four healthy volunteers were irradiated on both sides of their buttock skin with a single dose of solar-simulating UVR. One side was pretreated with a topical sunscreen. Biopsies from different time-points were immunostained for visualization of thymine dimers, p53 and proliferation. One single physiological dose of UVR generated widespread formation of thymine dimers throughout the epidermis 4h after irradiation. The level of thymine dimers decreased over time and was followed by a p53 response in the same cells. A late proliferative response was also found. The formation of thymine dimers, the p53 response and the late proliferative response were partially blocked by topical sunscreen. Large inter-individual differences in the kinetics of thymine dimer formation and repair as well as in the p53 response were evident in both sunscreen-protected and unprotected skin.

  12. Repairs of composite structures

    NASA Astrophysics Data System (ADS)

    Roh, Hee Seok

    Repair on damaged composite panels was conducted. To better understand adhesively bonded repair, the study investigates the effect of design parameters on the joint strength. The design parameters include bondline length, thickness of adherend and type of adhesive. Adhesives considered in this study were tested to measure their tensile material properties. Three types of adhesively bonded joints, single strap, double strap, and single lap joint were considered under changing bondline lengths, thickness of adherend and type of adhesive. Based on lessons learned from bonded joints, a one-sided patch repair method for composite structures was conducted. The composite patch was bonded to the damaged panel by either film adhesive FM-73M or paste adhesive EA-9394 and the residual strengths of the repaired specimens were compared under varying patch sizes. A new repair method using attachments has been suggested to enhance the residual strength. Results obtained through experiments were analyzed using finite element analysis to provide a better repair design and explain the experimental results. It was observed that the residual strength of the repaired specimen was affected by patch length. Method for rapid repairs of damaged composite structures was investigated. The damage was represented by a circular hole in a composite laminated plate. Pre-cured composite patches were bonded with a quick-curing commercial adhesive near (rather than over) the hole. Tensile tests were conducted on specimens repaired with various patch geometries. The test results showed that, among the methods investigated, the best repair method restored over 90% of the original strength of an undamaged panel. The interfacial stresses in the adhesive zone for different patches were calculated in order to understand the efficiencies of the designs of these patch repairs. It was found that the composite patch that yielded the best strength had the lowest interfacial peel stress between the patch and

  13. Single centre observational study to evaluate the safety and efficacy of the Proceed™ Ventral Patch to repair small ventral hernias.

    PubMed

    Bontinck, J; Kyle-Leinhase, I; Pletinckx, P; Vergucht, V; Beckers, R; Muysoms, F

    2014-10-01

    There is evidence that mesh repair for primary umbilical hernias results in less recurrences and similar wound complication rates compared to tissue repair. In recent years, several mesh devices for the repair of small ventral hernias have been developed, but some reports have been published on serious complications and adverse effects encountered with those mesh devices. The Proceed™ Ventral Patch (PVP™) is a partially absorbable lightweight polypropylene mesh. We introduced PVP™ in our department in April 2009 and collected patient data and outcome in an observational study of 101 consecutive patients until December 2011 (Clinical.Trials.gov: NCT01307696). In addition to the routine control 3 weeks postoperative, prospective follow-up included a questionnaire, clinical investigation and ultrasound after 12 months. The study included 91 primary (76 umbilical/15 epigastric) and 10 incisional ventral hernias (including 6 trocar hernias). In all patients a PVP™ with a diameter of 6.4 cm was used. Wound problems were the most frequent complication (n = 18). Follow-up of at least 12 months was achieved in 98 patients (97 %) and the mean follow-up time was 15.9 months. Follow-up by clinical examination diagnosed a recurrence in 11/92 patients (12.0 %). Only four patients were aware of their recurrent hernia, the seven others reported no problems in the questionnaire. The additional ultrasound performed did not reveal recurrences that were not already diagnosed by clinical examination. In five patients a reoperation for repair of the recurrence was performed (reoperation rate 5/98 = 5.1 %). Hernia defect size (p = 0.032) and type of hernia (p = 0.029) were found to be a significant risk factors for development of a recurrent hernia (Fisher's exact test). Hernia size was a significant risk factor both in a univariate (p = 0.005) and in a multivariate Cox model (p = 0.017). Incisional hernia was of borderline significance in a univariate (p

  14. The Clinical Effect of a Rotator Cuff Retear: A Meta-analysis of Arthroscopic Single-Row and Double-Row Repairs.

    PubMed

    Yang, Jeffrey; Robbins, Matthew; Reilly, Jordan; Maerz, Tristan; Anderson, Kyle

    2017-03-01

    The clinical effect of a retear after rotator cuff repair remains unclear. While some studies have indicated clinical deficits due to a retear, others have stated that a retear does not detrimentally affect outcomes. To conduct a meta-analysis comparing clinical outcomes between intact and retorn rotator cuffs after arthroscopic repair. Meta-analysis. A literature search using the terms "arthroscopic," "rotator cuff," "repair," "retear," "re-tear," "defect," "single-row," "double-row," "clinical outcomes," and "functional outcomes" was conducted. Article inclusion criteria were an adequate description of the surgical technique, stratification of outcomes by intact rotator cuff versus retear with a minimum of 1 year of follow-up, and documentation of the presence/absence of a full-thickness retear using imaging. Exclusion criteria were isolated subscapularis tears/repairs, labral repairs, infections, postoperative fractures, insufficient data or statistical indications, and postoperative data not stratified by retear versus intact rotator cuff. A meta-analysis was performed using a random-effects model on variables that had comparisons from at least 3 studies. Single-row (SR) and double-row (DR) studies were analyzed both separately and together in an "all arthroscopic repairs" (AAR) comparison. The calculated effect was considered significant at a P value <.05. Within the SR group, patients with a rotator cuff retear had a significantly lower Constant score (mean difference [95% CI], -6.79 [-8.94 to -4.65]; P < .001) and lower University of California, Los Angeles (UCLA) score (-3.21 [-5.27 to -1.15]; P = .002) but not higher pain (0.071 [-0.34 to 0.49]; P = .739). Within the DR group, patients with a rotator cuff retear had a significantly lower Constant score (mean difference [95% CI], -9.35 [-12.2 to -6.50]; P < .001), lower American Shoulder and Elbow Surgeons (ASES) score (-12.1 [-17.1 to -7.26]; P < .001), lower UCLA score (-3.07 [-4.85 to -1.29]; P < .001

  15. Coordination of Steps in Single-nucleotide Base Excision Repair Mediated by Apurinic/Apyrimidinic Endonuclease 1 and DNA Polymerase β*

    PubMed Central

    Liu, Yuan; Prasad, Rajendra; Beard, William A.; Kedar, Padmini S.; Hou, Esther W.; Shock, David D.; Wilson, Samuel H.

    2008-01-01

    The individual steps in single-nucleotide base excision repair (SN-BER) are coordinated to enable efficient repair without accumulation of cytotoxic DNA intermediates. The DNA transactions and various proteins involved in SN-BER of abasic sites are well known in mammalian systems. Yet, despite a wealth of information on SN-BER, the mechanism of step-by-step coordination is poorly understood. In this study we conducted experiments toward understanding step-by-step coordination during BER by comparing DNA binding specificities of two major human SN-BER enzymes, apurinic/aprymidinic endonuclease 1 (APE) and DNA polymerase β (Pol β). It is known that these enzymes do not form a stable complex in solution. For each enzyme, we found that DNA binding specificity appeared sufficient to explain the sequential processing of BER intermediates. In addition, however, we identified at higher enzyme concentrations a ternary complex of APE·Pol β·DNA that formed specifically at BER intermediates containing a 5′-deoxyribose phosphate group. Formation of this ternary complex was associated with slightly stronger Pol β gap-filling and much stronger 5′-deoxyribose phosphate lyase activities than was observed with the Pol β·DNA binary complex. These results indicate that step-by-step coordination in SN-BER can rely on DNA binding specificity inherent in APE and Pol β, although coordination also may be facilitated by APE·Pol β·DNA ternary complex formation with appropriate enzyme expression levels or enzyme recruitment to sites of repair. PMID:17355977

  16. Perioperative echocardiography-derived right ventricle function parameters and early outcomes after tetralogy of Fallot repair in mid-childhood: a single-center, prospective observational study.

    PubMed

    Raj, Ravi; Puri, Goverdhan Dutt; Jayant, Aveek; Thingnam, Shyam Kumar Singh; Singh, Rana Sandip; Rohit, Manoj Kumar

    2016-11-01

    Right ventricular (RV) function alterations are invariably present in all patients after tetralogy of Fallot (TOF) repair. Unlike the developed world where most of the patients with TOF are corrected in infancy, average age of presentation and thus surgery for these patients in the developing world may be higher. We aimed to study the correlation between RV function parameters such as tricuspid annular peak systolic excursion (TAPSE), fractional area change (FAC), and tricuspid annular peak systolic velocity (S') with early outcome variables after intracardiac repair for TOF. Fifty patients with a preoperative diagnosis of tetralogy of Fallot scheduled for corrective surgery were included in this single-center, prospective observational study. A preoperative transthoracic echocardiogram was performed to measure RV function parameters (FAC0, TAPSE0, S'0). Transthoracic echocardiography was repeated postoperatively to measure FAC1, TAPSE1, S'1 (day 1) and FAC2, TAPSE2, and S'2 (day 3). The relationship between preoperative and postoperative RV function parameters with in-hospital mortality, duration of mechanical ventilation, and intensive care unit stay was studied. The median age of patients was 6 years (range 1-14 years). Multiple stepwise logistic regression analysis showed RV FAC as best predictor of clinical outcome. Area under the receiver operating characteristic curve for postoperative RV function parameters, that is, FAC, TAPSE, and S' to predict early or delayed recovery was 0.944, 0.875, and 0.655, respectively. Among the RV function parameters studied, RV FAC best predicted the early outcome variables after TOF repair, followed by TAPSE while lateral tricuspid annular velocity S' being the least predictive. © 2016, Wiley Periodicals, Inc.

  17. The effect of TISSEEL fibrin sealant on seroma formation following complex abdominal wall hernia repair: a single institutional review and derived cost analysis.

    PubMed

    Azoury, S C; Rodriguez-Unda, N; Soares, K C; Hicks, C W; Baltodano, P A; Poruk, K E; Hu, Q L; Cooney, C M; Cornell, P; Burce, K; Eckhauser, F E

    2015-12-01

    The authors evaluated the ability of a fibrin sealant (TISSEEL™: Baxter Healthcare Corp, Deerfield, IL, USA) to reduce the incidence of post-operative seroma following abdominal wall hernia repair. We performed a 4-year retrospective review of patients undergoing abdominal wall hernia repair, with and without TISSEEL, by a single surgeon (FEE) at The Johns Hopkins Hospital. Demographics, surgical risk factors, operative data and 30-day outcomes, including wound complications and related interventions, were compared. The quantity and cost of Tisseel per case was reviewed. A total of 250 patients were evaluated: 127 in the TISSEEL group and 123 in the non-TISSEEL control group. The average age for both groups was 56.6 years (P = 0.97). The majority of patients were female (TISSEEL 52.8%, non-TISSEEL 56.1%, P = 0.59) and ASA Class III (TISSEEL 56.7%, non-TISSEEL 58.5%, P = 0.40). There was no difference in the average defect size for both groups (TISSEEL 217 ± 187.6 cm(2), non-TISSEEL 161.3 ± 141.5 cm(2), P = 0.36). Surgical site occurrences occurred in 18.1% of the TISSEEL and 13% of the non-TISSEEL group (P = 0.27). There was a trend towards an increased incidence of seroma in the TISSEEL group (TISSEEL 11%, non-TISSEEL 4.9%, P = 0.07). A total of $124,472.50 was spent on TISSEEL, at an average cost of $995.78 per case. In the largest study to date, TISSEEL™ application offered no advantage for the reduction of post-operative seroma formation following complex abdominal hernia repair. Moreover, the use of this sealant was associated with significant costs.

  18. DNA single-strand breaks, double-strand breaks, and crosslinks in rat testicular germ cells: Measurements of their formation and repair by alkaline and neutral filter elution

    SciTech Connect

    Bradley, M.O.; Dysart, G. )

    1985-06-01

    This work describes a neutral and alkaline elution method for measuring DNA single-strand breaks (SSBs), DNA double-strand breaks (DSBs), and DNA-DNA crosslinks in rat testicular germ cells after treatments in vivo or in vitro with both chemical mutagens and gamma-irradiation. The methods depend upon the isolation of testicular germ cells by collagenase and trypsin digestion, followed by filtration and centrifugation. {sup 137}Cs irradiation induced both DNA SSBs and DSBs in germ cells held on ice in vitro. Irradiation of the whole animal indicated that both types of DNA breaks are induced in vivo and can be repaired. A number of germ cell mutagens induced either DNA SSBs, DSBs, or cross-links after in vivo and in vitro dosing. These chemicals included methyl methanesulfonate, ethyl methanesulfonate, ethyl nitrosourea, dibromochlorpropane, ethylene dibromide, triethylene melamine, and mitomycin C. These results suggest that the blood-testes barrier is relatively ineffective for these mutagens, which may explain in part their in vivo mutagenic potency. This assay should be a useful screen for detecting chemical attack upon male germ-cell DNA and thus, it should help in the assessment of the mutagenic risk of chemicals. In addition, this approach can be used to study the processes of SSB, DSB, and crosslink repair in DNA of male germ cells, either from all stages or specific stages of development.

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

    PubMed Central

    Hu, Jinchuan; Adar, Sheera; Selby, Christopher P.

    2015-01-01

    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. PMID:25934506

  20. Methotrexate induces DNA damage and inhibits homologous recombination repair in choriocarcinoma cells

    PubMed Central

    Xie, Lisha; Zhao, Tiancen; Cai, Jing; Su, You; Wang, Zehua; Dong, Weihong

    2016-01-01

    Objective The objective of this study was to investigate the mechanism of sensitivity to methotrexate (MTX) in human choriocarcinoma cells regarding DNA damage response. Methods Two choriocarcinoma cancer cell lines, JAR and JEG-3, were utilized in this study. An MTX-sensitive osteosarcoma cell line MG63, an MTX-resistant epithelial ovarian cancer cell line A2780 and an MTX-resistant cervical adenocarcinoma cell line Hela served as controls. Cell viability assay was carried out to assess MTX sensitivity of cell lines. MTX-induced DNA damage was evaluated by comet assay. Quantitative reverse transcription polymerase chain reaction was used to detect the mRNA levels of BRCA1, BRCA2, RAD51 and RAD52. The protein levels of γH2AX, RAD 51 and p53 were analyzed by Western blot. Results Remarkable DNA strand breaks were observed in MTX-sensitive cell lines (JAR, JEG-3 and MG63) but not in MTX-resistant cancer cells (A2780 and Hela) after 48 h of MTX treatment. Only in the choriocarcinoma cells, the expression of homologous recombination (HR) repair gene RAD51 was dramatically suppressed by MTX in a dose- and time-dependent manner, accompanied with the increase in p53. Conclusion The MTX-induced DNA strand breaks accompanied by deficiencies in HR repair may contribute to the hypersensitivity to chemotherapy in choriocarcinoma. PMID:27895503

  1. The role of Holliday junction resolvases in the repair of spontaneous and induced DNA damage.

    PubMed

    Agmon, Neta; Yovel, Moran; Harari, Yaniv; Liefshitz, Batia; Kupiec, Martin

    2011-09-01

    DNA double-strand breaks (DSBs) and other lesions occur frequently during cell growth and in meiosis. These are often repaired by homologous recombination (HR). HR may result in the formation of DNA structures called Holliday junctions (HJs), which need to be resolved to allow chromosome segregation. Whereas HJs are present in most HR events in meiosis, it has been proposed that in vegetative cells most HR events occur through intermediates lacking HJs. A recent screen in yeast has shown HJ resolution activity for a protein called Yen1, in addition to the previously known Mus81/Mms4 complex. Yeast strains deleted for both YEN1 and MMS4 show a reduction in growth rate, and are very sensitive to DNA-damaging agents. In addition, we investigate the genetic interaction of yen1 and mms4 with mutants defective in different repair pathways. We find that in the absence of Yen1 and Mms4 deletion of RAD1 or RAD52 have no further effect, whereas additional sensitivity is seen if RAD51 is deleted. Finally, we show that yeast cells are unable to carry out meiosis in the absence of both resolvases. Our results show that both Yen1 and Mms4/Mus81 play important (although not identical) roles during vegetative growth and in meiosis.

  2. The role of Holliday junction resolvases in the repair of spontaneous and induced DNA damage

    PubMed Central

    Agmon, Neta; Yovel, Moran; Harari, Yaniv; Liefshitz, Batia; Kupiec, Martin

    2011-01-01

    DNA double-strand breaks (DSBs) and other lesions occur frequently during cell growth and in meiosis. These are often repaired by homologous recombination (HR). HR may result in the formation of DNA structures called Holliday junctions (HJs), which need to be resolved to allow chromosome segregation. Whereas HJs are present in most HR events in meiosis, it has been proposed that in vegetative cells most HR events occur through intermediates lacking HJs. A recent screen in yeast has shown HJ resolution activity for a protein called Yen1, in addition to the previously known Mus81/Mms4 complex. Yeast strains deleted for both YEN1 and MMS4 show a reduction in growth rate, and are very sensitive to DNA-damaging agents. In addition, we investigate the genetic interaction of yen1 and mms4 with mutants defective in different repair pathways. We find that in the absence of Yen1 and Mms4 deletion of RAD1 or RAD52 have no further effect, whereas additional sensitivity is seen if RAD51 is deleted. Finally, we show that yeast cells are unable to carry out meiosis in the absence of both resolvases. Our results show that both Yen1 and Mms4/Mus81 play important (although not identical) roles during vegetative growth and in meiosis. PMID:21609961

  3. Mismatch repair.

    PubMed

    Fishel, Richard

    2015-10-30

    Highly conserved MutS homologs (MSH) and MutL homologs (MLH/PMS) are the fundamental components of mismatch repair (MMR). After decades of debate, it appears clear that the MSH proteins initiate MMR by recognizing a mismatch and forming multiple extremely stable ATP-bound sliding clamps that diffuse without hydrolysis along the adjacent DNA. The function(s) of MLH/PMS proteins is less clear, although they too bind ATP and are targeted to MMR by MSH sliding clamps. Structural analysis combined with recent real-time single molecule and cellular imaging technologies are providing new and detailed insight into the thermal-driven motions that animate the complete MMR mechanism.

  4. Initiation of DNA double strand break repair: signaling and single-stranded resection dictate the choice between homologous recombination, non-homologous end-joining and alternative end-joining.

    PubMed

    Grabarz, Anastazja; Barascu, Aurélia; Guirouilh-Barbat, Josée; Lopez, Bernard S

    2012-01-01

    A DNA double strand break (DSB) is a highly toxic lesion, which can generate genetic instability and profound genome rearrangements. However, DSBs are required to generate diversity during physiological processes such as meiosis or the establishment of the immune repertoire. Thus, the precise regulation of a complex network of processes is necessary for the maintenance of genomic stability, allowing genetic diversity but protecting against genetic instability and its consequences on oncogenesis. Two main strategies are employed for DSB repair: homologous recombination (HR) and non-homologous end-joining (NHEJ). HR is initiated by single-stranded DNA (ssDNA) resection and requires sequence homology with an intact partner, while NHEJ requires neither resection at initiation nor a homologous partner. Thus, resection is an pivotal step at DSB repair initiation, driving the choice of the DSB repair pathway employed. However, an alternative end-joining (A-EJ) pathway, which is highly mutagenic, has recently been described; A-EJ is initiated by ssDNA resection but does not require a homologous partner. The choice of the appropriate DSB repair system, for instance according the cell cycle stage, is essential for genome stability maintenance. In this context, controlling the initial events of DSB repair is thus an essential step that may be irreversible, and the wrong decision should lead to dramatic consequences. Here, we first present the main DSB repair mechanisms and then discuss the importance of the choice of the appropriate DSB repair pathway according to the cell cycle phase. In a third section, we present the early steps of DSB repair i.e., DSB signaling, chromatin remodeling, and the regulation of ssDNA resection. In the last part, we discuss the competition between the different DSB repair mechanisms. Finally, we conclude with the importance of the fine tuning of this network for genome stability maintenance and for tumor protection in fine.

  5. Single shot spinal anesthesia with very low hyperbaric bupivacaine dose (3.75 mg) for hip fracture repair surgery in the elderly. A randomized, double blinded study.

    PubMed

    Errando, C L; Peiró, C M; Gimeno, A; Soriano, J L

    2014-11-01

    Single shot spinal anesthesia is used worldwide for hip fracture repair surgery in the elderly. Arterial hypotension is a frequent adverse effect. We hypothesized that lowering local anesthetics dose could decrease the incidence of arterial hypotension, while maintaining quality of surgical anesthesia. In a randomized double blinded study, 66 patients over the age of 65 years, with hip fracture needing surgical repair, were assigned to B0.5 group 7.5mg hyperbaric bupivacaine 5mg/ml (control group), and B0.25 group 3.75mg hyperbaric bupivacaine 2.5mg/ml (study group). Sensory and motor block level, and hemodynamic parameters including blood presure, heart rate and vasopressor dose administration were registered, along with rescue anesthesia needs, the feasibility of surgery, its duration, and regression time of sensory anesthesia to T12. After exclusions, 61 patients were included in the final analysis. Arterial hypotension incidence was lower in the B0.25 group (at the 5, 10, and 15min determinations), and a lower amount of vasopressor drugs was needed (mean accumulated ephedrine dose 1.6mg vs. 8.7mg in the B0.5 group, p<0.002). Sensory block regression time to T12 was shorter in the B0.25 group, mean 78.6±23.6 (95% CI 51.7-110.2)min vs. 125.5±37.9 (95% CI 101.7-169.4)min in the B0.5 group, p=0.033. All but one patient in the B0.25 group were operated on under the anesthetic procedure first intended. No rescue anesthesia was needed. Lowering bupivacaine dose for single shot spinal anesthesia for hip fracture repair surgery in elderly patients was effective in decreasing the occurrence of arterial hypotension and vasopressor use, while intraoperative quality remained. Copyright © 2014 Sociedad Española de Anestesiología, Reanimación y Terapéutica del Dolor. Publicado por Elsevier España, S.L.U. All rights reserved.

  6. Hemorrhoidal artery ligation (HAL) and rectoanal repair (RAR): retrospective analysis of 408 patients in a single center.

    PubMed

    Scheyer, M; Antonietti, E; Rollinger, G; Lancee, S; Pokorny, H

    2015-01-01

    Rectoanal repair (RAR), which combines doppler-guided hemorrhoidal artery ligation (HAL) and mucopexy via lifting of the hemorrhoidal prolapse, offers a minimally invasive alternative to conventional hemorrhoidectomy. Patients with grade II hemorrhoids were treated with HAL, and patients with grade III and IV hemorrhoids were treated with the RAR procedure by two surgeons. Postoperative follow-up was performed clinically and by proctoscopy after 8 weeks routinely, and long-term follow-up was performed using a standardized postal questionnaire. The overall complication rate was 29% (n = 118). After short-term follow-up, 26% (n = 106) of patients reported recurrent or persistent prolapsing piles, while 21% (n = 86) of patients had recurrent bleeding. After long-term follow-up, 24% (n = 98) of patients reported prolapsing piles, 3% (n = 12) bleeding, 3% (n = 12) pruritus, and 2% (n = 8) anal pain, while 20% (n = 82) complained of persistent mixed symptoms. HAL and RAR provide prolonged relief for patients with hemorrhoidal disease whose main symptoms are bleeding, pruritus and pain but not for patients with prolapse as an initial indication.

  7. Tendon repair

    MedlinePlus

    ... the area to see if there are any injuries to nerves and blood vessels. When the repair is complete, the wound is closed. If the tendon damage is too severe, the repair and reconstruction ... to repair part of the injury. Another surgery will be done at a later ...

  8. 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.

  9. Rgf1p (Rho1p GEF) is required for double-strand break repair in fission yeast.

    PubMed

    Manjón, Elvira; Edreira, Tomás; Muñoz, Sofía; Sánchez, Yolanda

    2017-05-19

    Rho GTPases are conserved molecules that control cytoskeletal dynamics. These functions are expedited by Rho GEFs that stimulate the release of GDP to enable GTP binding, thereby allowing Rho proteins to initiate intracellular signaling. How Rho GEFs and Rho GTPases protect cells from DNA damage is unknown. Here, we explore the extreme sensitivity of a deletion mutation in the Rho1p exchange factor Rgf1p to the DNA break/inducing antibiotic phleomycin (Phl). The Rgf1p mutant cells are defective in reentry into the cell cycle following the induction of severe DNA damage. This phenotype correlates with the inability of rgf1Δ cells to efficiently repair fragmented chromosomes after Phl treatment. Consistent with this observation Rad11p (ssDNA binding protein, RPA), Rad52p, Rad54p and Rad51p, which facilitate strand invasion in the process of homology-directed repair (HDR), are permanently stacked in Phl-induced foci in rgf1Δ cells. These phenotypes are phenocopied by genetic inhibition of Rho1p. Our data provide evidence that Rgf1p/Rho1p activity positively controls a repair function that confers resistance against the anti-cancer drug Phl. © The Author(s) 2017. Published by Oxford University Press on behalf of Nucleic Acids Research.

  10. Sensor and effector kinases in DNA damage checkpoint regulate capacity for homologous recombination repair of fission yeast in G2 phase.

    PubMed

    Yasuhira, Shinji; Saito, Takeshi; Maesawa, Chihaya; Masuda, Tomoyuki

    2012-08-01

    Although the G2/M DNA damage checkpoint is currently viewed as a set of coordinated cellular responses affecting both cell cycle progression and non-cell cycle targets, the relative contributions of the two target categories to DNA repair and cell survival after exposure to ionizing radiation have not been clearly addressed. We investigated how rad3 (ATR ortholog) or chk1/cds1 (CHK1/CHK2 orthologs) null mutations change the kinetics of double-strand break (DSB) repair in Schizosaccharomyces pombe cells under conditions of forced G2 arrest. After 200-Gy γ-ray irradiation, DSBs were repaired in rad3Δ cdc25-22 or chk1Δ cds1Δ cdc25-22 cells, almost as efficiently as in cdc25-22 cells at the restrictive temperature. In contrast, little repair was observed in the checkpoint-deficient cells up to 4h after higher-dose (500Gy) irradiation, whereas repair was still efficient in the control cdc25-22 cells. Immediate loss of viability appeared not be responsible for the repair defect after the higher dose, since both checkpoint-proficient and deficient cells with cdc25-22 allele synchronously resumed cycling with a similar time course when released to the permissive temperature 4h after irradiation. Recruitment of repair proteins Rad11 (Rpa1 ortholog), Rad22 (Rad52 ortholog), and Rhp54 (Rad54 ortholog) to the damage sites was not significantly impaired in the checkpoint-deficient cells, whereas their release was profoundly delayed. Our results suggest that sensor and effector kinases in the damage checkpoint machinery affect the efficiency of repair downstream of, or in parallel with the core repair reaction. Copyright © 2012 Elsevier B.V. All rights reserved.

  11. INVESTIGATION OF DNA REPAIR BY SISTER CHROMATID EXCHANGE (SCE) ANALYSIS AND THE ALKALINE SINGLE CELL GEL ASSAY (SCG) IN MAMMALIAN GO-LYMPHOCYTES AFTER IN VITRO EXPOSURE TO ETHYLENE OXIDE (EO)

    EPA Science Inventory

    Investigation ofDNA Repair by Sister Chromatid Exchange (SCE) Analysis and the Alkaline Single Cell Gel Assay (SCG) in Mammalian Go-Lymphocytes after In Vitro Exposure to Ethylene Oxide (EO).

    EO is a large volume chemical used primarily as an intermediate in manufacturing...

  12. INVESTIGATION OF DNA REPAIR BY SISTER CHROMATID EXCHANGE (SCE) ANALYSIS AND THE ALKALINE SINGLE CELL GEL ASSAY (SCG) IN MAMMALIAN GO-LYMPHOCYTES AFTER IN VITRO EXPOSURE TO ETHYLENE OXIDE (EO)

    EPA Science Inventory

    Investigation ofDNA Repair by Sister Chromatid Exchange (SCE) Analysis and the Alkaline Single Cell Gel Assay (SCG) in Mammalian Go-Lymphocytes after In Vitro Exposure to Ethylene Oxide (EO).

    EO is a large volume chemical used primarily as an intermediate in manufacturing...

  13. Single-Walled Carbon Nanotubes Chemically Functionalized with Polyethylene Glycol Promote Tissue Repair in a Rat Model of Spinal Cord Injury

    PubMed Central

    Roman, Jose A.; Niedzielko, Tracy L.; Haddon, Robert C.; Parpura, Vladimir

    2011-01-01

    Abstract Traumatic spinal cord injury (SCI) induces tissue damage and results in the formation of a cavity that inhibits axonal regrowth. Filling this cavity with a growth-permissive substrate would likely promote regeneration and repair. Single-walled carbon nanotubes functionalized with polyethylene glycol (SWNT-PEG) have been shown to increase the length of selected neurites in vitro. We hypothesized that administration of SWNT-PEG after experimental SCI will promote regeneration of axons into the lesion cavity and functional recovery of the hindlimbs. To evaluate this hypothesis, complete transection SCI was induced at the T9 vertebral level in adult female rats. One week after transection, the epicenter of the lesion was injected with 25 μL of either vehicle (saline), or 1 μg/mL, 10 μg/mL, or 100 μg/mL of SWNT-PEG. Behavioral analysis was conducted before injury, before treatment, and once every 7 days for 28 days after treatment. At 28 days post-injection the rats were euthanized and spinal cord tissue was extracted. Immunohistochemistry was used to detect the area of the cyst, the extent of the glial scar, and axonal morphology. We found that post-SCI administration of SWNT-PEG decreased lesion volume, increased neurofilament-positive fibers and corticospinal tract fibers in the lesion, and did not increase reactive gliosis. Additionally, post-SCI administration of SWNT-PEG induced a modest improvement in hindlimb locomotor recovery without inducing hyperalgesia. These data suggest that SWNT-PEG may be an effective material to promote axonal repair and regeneration after SCI. PMID:21303267

  14. Single-walled carbon nanotubes chemically functionalized with polyethylene glycol promote tissue repair in a rat model of spinal cord injury.

    PubMed

    Roman, Jose A; Niedzielko, Tracy L; Haddon, Robert C; Parpura, Vladimir; Floyd, Candace L

    2011-11-01

    Traumatic spinal cord injury (SCI) induces tissue damage and results in the formation of a cavity that inhibits axonal regrowth. Filling this cavity with a growth-permissive substrate would likely promote regeneration and repair. Single-walled carbon nanotubes functionalized with polyethylene glycol (SWNT-PEG) have been shown to increase the length of selected neurites in vitro. We hypothesized that administration of SWNT-PEG after experimental SCI will promote regeneration of axons into the lesion cavity and functional recovery of the hindlimbs. To evaluate this hypothesis, complete transection SCI was induced at the T9 vertebral level in adult female rats. One week after transection, the epicenter of the lesion was injected with 25??L of either vehicle (saline), or 1??g/mL, 10??g/mL, or 100??g/mL of SWNT-PEG. Behavioral analysis was conducted before injury, before treatment, and once every 7 days for 28 days after treatment. At 28 days post-injection the rats were euthanized and spinal cord tissue was extracted. Immunohistochemistry was used to detect the area of the cyst, the extent of the glial scar, and axonal morphology. We found that post-SCI administration of SWNT-PEG decreased lesion volume, increased neurofilament-positive fibers and corticospinal tract fibers in the lesion, and did not increase reactive gliosis. Additionally, post-SCI administration of SWNT-PEG induced a modest improvement in hindlimb locomotor recovery without inducing hyperalgesia. These data suggest that SWNT-PEG may be an effective material to promote axonal repair and regeneration after SCI.

  15. Autologous collagen induced chondrogenesis (ACIC: Shetty-Kim technique) - A matrix based acellular single stage arthroscopic cartilage repair technique.

    PubMed

    Shetty, Asode Ananthram; Kim, Seok Jung; Shetty, Vishvas; Jang, Jae Deog; Huh, Sung Woo; Lee, Dong Hwan

    2016-01-01

    The defects of articular cartilage in the knee joint are a common degenerative disease and currently there are several established techniques to treat this problem, each with their own advantages and shortcomings. Autologous chondrocyte implantation is the current gold standard but the technique is expensive, time-consuming and most versions require two stage procedures and an arthrotomy. Autologous collagen induced chondrogenesis (ACIC) is a single-stage arthroscopic procedure and we developed. This method uses microfracture technique with atelocollagen mixed with fibrin gel to treat articular cartilage defects. We introduce this ACIC techniques and its scientific background.

  16. Periradicular repair after two-visit endodontic treatment using two different intracanal medications compared to single-visit endodontic treatment.

    PubMed

    Silveira, Adriana M Vieira; Lopes, Hélio P; Siqueira, José F; Macedo, Sérgio B; Consolaro, Alberto

    2007-01-01

    The number of appointments necessary to treat infected root canals is one of the most controversial issues in endodontics. This study evaluated, in dogs, the response of the periradicular tissues to the endodontic treatment of infected root canals performed in a single visit or in two visits, using different interappointment dressings. Periradicular lesions were induced by inoculating Enterococcus faecalis in the root canals. After confirming that a periradicular lesion developed, the root canals were treated within one or two visits, using either ozonized oil or calcium hydroxide in camphorated paramonochlorophenol (CMCP) as an intracanal medication. After 6 months, the animals were sacrificed and the specimens were processed for histological and histobacteriological analysis. The root canals treated in a single visit showed a success rate of 46%. When a calcium hydroxide/CMCP-based interappointment intracanal medication was used, 74% of the cases were categorized as success. In cases where ozonized oil was used as the intracanal medication, a success rate of 77% was observed. These results of the present study demonstrated that the two-visit treatment offered a higher success rate compared to one-visit therapy. In addition, ozonized oil may potentially be used as an intracanal medication.

  17. Multiple interactions among the components of the recombinational DNA repair system in Schizosaccharomyces pombe.

    PubMed Central

    Tsutsui, Y; Khasanov, F K; Shinagawa, H; Iwasaki, H; Bashkirov, V I

    2001-01-01

    Schizosaccharomyces pombe Rhp55 and Rhp57 are RecA-like proteins involved in double-strand break (DSB) repair. Here we demonstrate that Rhp55 and Rhp57 proteins strongly interact in vivo, similar to Saccharomyces cerevisiae Rad55p and Rad57p. Mutations in the conserved ATP-binding/hydrolysis folds of both the Rhp55 and Rhp57 proteins impaired their function in DNA repair but not in cell proliferation. However, when combined, ATPase fold mutations in Rhp55p and Rhp57p resulted in severe defects of both functions, characteristic of the deletion mutants. Yeast two-hybrid analysis also revealed other multiple in vivo interactions among S. pombe proteins involved in recombinational DNA repair. Similar to S. cerevisiae Rad51p-Rad54p, S. pombe Rhp51p and Rhp54p were found to interact. Both putative Rad52 homologs in S. pombe, Rad22p and Rti1p, were found to interact with the C-terminal region of Rhp51 protein. Moreover, Rad22p and Rti1p exhibited mutual, as well as self-, interactions. In contrast to the S. cerevisiae interacting pair Rad51p-Rad55p, S. pombe Rhp51 protein strongly interacted with Rhp57 but not with Rhp55 protein. In addition, the Rti1 and Rad22 proteins were found to form a complex with the large subunit of S. pombe RPA. Our data provide compelling evidence that most, but not all, of the protein-protein interactions found in S. cerevisiae DSB repair are evolutionarily conserved. PMID:11560889

  18. Clubfoot repair

    MedlinePlus

    ... Clubfoot release; Talipes equinovarus - repair; Tibialis anterior tendon transfer ... complete blood count and check electrolytes or clotting factors) Always tell your child's provider: What drugs your ...

  19. Long-term outcomes of 1326 laparoscopic incisional and ventral hernia repair with the routine suturing concept: a single institution experience.

    PubMed

    Chelala, E; Baraké, H; Estievenart, J; Dessily, M; Charara, F; Allé, J L

    2016-02-01

    This retrospective chart analysis reports and assesses the long-term (beyond 10 years) safety and efficiency of a single institution's experience in 1326 laparoscopic incisional and ventral hernia repairs (LIVHR), defending the principle of the suturing defect (augmentation repair concept) prior to laparoscopic reinforcement with a composite mesh (IPOM Plus). This study aims to prove the feasibility and validity of IPOM Plus repair, among other concepts, as a well-justified treatment of incisional or ventral hernias, rendering a good long-term outcome result. A single institution's systematic retrospective review of 1326 LIVHR was conducted between the years 2000 and 2014. A standardized technique of routine closure of the defect prior to the intraperitoneal onlay mesh (IPOM) reinforcement was performed in all patients. The standardized technique of "defect closure" by laparoscopy approximating the linea alba under physiological tension was assigned by either the transparietal U reverse interrupted stitches or the extracorporeal closure in larger defects. All patients benefited from the implant Parietex composite mesh through an Intraperitoneal Onlay Mesh placement with transfacial suturing. LIVHR was performed on 1326 patients, 52.57% female and 47.43% male. The majority of our patients were young (mean age 52.19 years) and obese (average BMI 32.57 kg/m2). The mean operating time was 70 min and hospital stay 2 days, with a mean follow-up of 78 months. On the overall early complications of 5.78%, we achieved over time the elimination of the dead space by routine closure of the defect, thus reducing seroma formation to 2.56%, with a low risk of infection <1%. Post-op sepsis occurred in only nine cases. Three secondary serosal breakdowns and two late perforations were re-operated, and three diabetic patients had infected hematomas, necessitating mesh removal. Through technical improvement in the suturing concept and our growing experience, we managed to reduce the

  20. Mus81-Mms4 Functions as a Single Heterodimer To Cleave Nicked Intermediates in Recombinational DNA Repair

    PubMed Central

    Schwartz, Erin K.; Wright, William D.; Ehmsen, Kirk T.; Evans, James E.; Stahlberg, Henning

    2012-01-01

    The formation of crossovers is a fundamental genetic process. The XPF-family endonuclease Mus81-Mms4 (Eme1) contributes significantly to crossing over in eukaryotes. A key question is whether Mus81-Mms4 can process Holliday junctions that contain four uninterrupted strands. Holliday junction cleavage requires the coordination of two active sites, necessitating the assembly of two Mus81-Mms4 heterodimers. Contrary to this expectation, we show that Saccharomyces cerevisiae Mus81-Mms4 exists as a single heterodimer both in solution and when bound to DNA substrates in vitro. Consistently, immunoprecipitation experiments demonstrate that Mus81-Mms4 does not multimerize in vivo. Moreover, chromatin-bound Mus81-Mms4 does not detectably form higher-order multimers. We show that Cdc5 kinase activates Mus81-Mms4 nuclease activity on 3′ flaps and Holliday junctions in vitro but that activation does not induce a preference for Holliday junctions and does not induce multimerization of the Mus81-Mms4 heterodimer. These data support a model in which Mus81-Mms4 cleaves nicked recombination intermediates such as displacement loops (D-loops), nicked Holliday junctions, or 3′ flaps but not intact Holliday junctions with four uninterrupted strands. We infer that Mus81-dependent crossing over occurs in a noncanonical manner that does not involve the coordinated cleavage of classic Holliday junctions. PMID:22645308

  1. Clinical Outcomes of Modified Mason-Allen Single-Row Repair for Bursal-Sided Partial-Thickness Rotator Cuff Tears: Comparison With the Double-Row Suture-Bridge Technique.

    PubMed

    Shin, Sang-Jin; Kook, Seung-Hwan; Rao, Nandan; Seo, Myeong-Jae

    2015-08-01

    Various repair techniques have been reported for the operative treatment of bursal-sided partial-thickness rotator cuff tears. Recently, arthroscopic single-row repair using a modified Mason-Allen technique has been introduced. The arthroscopic, modified Mason-Allen single-row technique with preservation of the articular-sided tendon provides satisfactory clinical outcomes and similar results to the double-row suture-bridge technique after conversion of a partial-thickness tear to a full-thickness tear. Cohort study; Level of evidence, 3. A retrospective study was conducted on 84 consecutive patients with symptomatic, bursal-sided partial-thickness rotator cuff tears involving more than 50% thickness of the tendon. A total of 47 patients were treated by the modified Mason-Allen single-row repair technique, preserving the articular-sided tendon, and 37 patients were treated by the double-row suture-bridge repair technique after conversion to a full-thickness tear. The clinical and functional outcomes were evaluated using the American Shoulder and Elbow Surgeons (ASES) and Constant scores and a visual analog scale (VAS) for pain and satisfaction of patients. Magnetic resonance imaging (MRI) was used to analyze the integrity of tendons at 6-month follow-up. Patients were followed up for a mean of 32.5 months. In the 47 patients treated with the modified Mason-Allen suture technique, the VAS score decreased from a preoperative mean of 5.3 ± 0.3 to 0.9 ± 0.5 at the time of final follow-up. There was a statistically significant increase in the mean ASES score (from 45.4 ± 2.9 to 88.6 ± 4.5) and mean Constant score (from 66.9 ± 2.6 to 88.1 ± 2.4) (P < .001). Four of 47 patients (8.5%) demonstrated retears at 6-month postoperative MRI. There was no statistical difference in terms of functional outcomes and the retear rate compared with those of patients with the suture-bridge repair technique (3 patients, 8.1%). However, the mean number of suture anchors used in the

  2. Modified Single-Patch Technique Versus Two-Patch Technique for the Repair of Complete Atrioventricular Septal Defect: A Meta-Analysis.

    PubMed

    Li, Dongxu; Fan, Qiang; Iwase, Tomoyuki; Hirata, Yasutaka; An, Qi

    2017-07-15

    Technical selection for surgical repair of complete atrioventricular septal defect (CAVSD) still remains controversial. This meta-analysis aimed to compare the modified single-patch (MP) technique with the two-patch (TP) technique for patients with CAVSD. Relevant studies comparing the MP technique with the TP technique were identified through a literature search using MEDLINE, EMBASE, Google Scholar, Cochrane Library, and the China National Knowledge Infrastructure databases. The variables were ventricular septal defect (VSD) size, cardiopulmonary bypass (CBP) time, aortic cross-clamp (ACC) time, intensive care unit stay, hospital stay, and other outcomes involving mortality, left ventricular outflow tract obstruction, atrioventricular valve regurgitation, residual septal shunt, atrioventricular block, and reoperation. A random-effect/fixed-effect model was used to summarize the estimates of mean difference/odds ratio with 95% confidence interval. Subgroup analysis stratified by region was performed. Fifteen publications involving 1034 patients were included. This meta-analysis demonstrated that (1) VSD size in the MP group was significantly smaller; (2) CBP time, ACC time, and hospital stay in the MP group experienced improvement; (3) Other postoperative outcomes showed no significant differences between two groups; and (4) The trends in China and other countries were close. The MP and TP techniques had comparable outcomes; however, the MP technique was performed with significantly shorter CBP and ACC times in patients with smaller VSDs. Given this limitation of data, the results of comparison of the two techniques in patients with larger VSDs remain unknown. Further studies are needed.

  3. Proximal Hamstring Repair Strength

    PubMed Central

    Harvey, Margaret Ann; Singh, Hardeep; Obopilwe, Elifho; Charette, Ryan; Miller, Suzanne

    2015-01-01

    Background: Proximal hamstring repair for complete ruptures has become a common treatment. There is no consensus in the literature about postoperative rehabilitation protocols following proximal hamstring repair. Some protocols describe bracing to prevent hip flexion or knee extension while others describe no immobilization. There are currently no biomechanical studies evaluating proximal hamstring repairs; nor are there any studies evaluating the effect of different hip flexion angles on these repairs. Hypothesis: As hip flexion increases from 0° to 90°, there will be a greater gap with cyclical loading. Study Design: Controlled laboratory study. Methods: Proximal hamstring insertions were detached from the ischial tuberosity in 24 cadavers and were repaired with 3 single-loaded suture anchors in the hamstring footprint with a Krakow suture technique. Cyclic loading from 10 to 125 N at 1 Hz was then performed for 0°, 45°, and 90° of hip flexion for 1500 cycles. Gap formation, stiffness, yield load, ultimate load, and energy to ultimate load were compared between groups using paired t tests. Results: Cyclic loading demonstrated the least amount of gap formation (P < .05) at 0° of hip flexion (2.39 mm) and most at 90° of hip flexion (4.19 mm). There was no significant difference in ultimate load between hip flexion angles (326, 309, and 338 N at 0°, 45°, and 90°, respectively). The most common mode of failure occurred with knot/suture failure (n = 17). Conclusion: Increasing hip flexion from 0° to 90° increases the displacement across proximal hamstring repairs. Postoperative bracing that limits hip flexion should be considered. Clinical Relevance: Repetitive motion involving hip flexion after a proximal hamstring repair may cause compromise of the repair. PMID:26665049

  4. Unique DNA repair gene variations and potential associations with the primary antibody deficiency syndromes IgAD and CVID.

    PubMed

    Offer, Steven M; Pan-Hammarström, Qiang; Hammarström, Lennart; Harris, Reuben S

    2010-08-18

    Despite considerable effort, the genetic factors responsible for >90% of the antibody deficiency syndromes IgAD and CVID remain elusive. To produce a functionally diverse antibody repertoire B lymphocytes undergo class switch recombination. This process is initiated by AID-catalyzed deamination of cytidine to uridine in switch region DNA. Subsequently, these residues are recognized by the uracil excision enzyme UNG2 or the mismatch repair proteins MutSalpha (MSH2/MSH6) and MutLalpha (PMS2/MLH1). Further processing by ubiquitous DNA repair factors is thought to introduce DNA breaks, ultimately leading to class switch recombination and expression of a different antibody isotype. Defects in AID and UNG2 have been shown to result in the primary immunodeficiency hyper-IgM syndrome, leading us to hypothesize that additional, potentially more subtle, DNA repair gene variations may underlie the clinically related antibody deficiencies syndromes IgAD and CVID. In a survey of twenty-seven candidate DNA metabolism genes, markers in MSH2, RAD50, and RAD52 were associated with IgAD/CVID, prompting further investigation into these pathways. Resequencing identified four rare, non-synonymous alleles associated with IgAD/CVID, two in MLH1, one in RAD50, and one in NBS1. One IgAD patient carried heterozygous non-synonymous mutations in MLH1, MSH2, and NBS1. Functional studies revealed that one of the identified mutations, a premature RAD50 stop codon (Q372X), confers increased sensitivity to ionizing radiation. Our results are consistent with a class switch recombination model in which AID-catalyzed uridines are processed by multiple DNA repair pathways. Genetic defects in these DNA repair pathways may contribute to IgAD and CVID.

  5. Hypospadias repair: the seagull meatoplasty.

    PubMed

    Roberts, A H; Dickinson, J C

    1987-01-01

    An operation is described which has been used in six cases to produce a single stream of urine in patients who were spraying following hypospadias repair. It has also been used in four patients to advance the meatus terminally.

  6. Aneurysm Repair

    MedlinePlus

    ... repair of abdominal aortic aneurysms Cardiologists at the Texas Heart Institute were among the first to use ... comments. Terms of Use and Privacy Policy © Copyright Texas Heart Institute All rights reserved.

  7. 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

  8. Tissue repair

    PubMed Central

    2010-01-01

    As living beings that encounter every kind of traumatic event from paper cut to myocardial infarction, we must possess ways to heal damaged tissues. While some animals are able to regrow complete body parts following injury (such as the earthworm who grows a new head following bisection), humans are sadly incapable of such feats. Our means of recovery following tissue damage consists largely of repair rather than pure regeneration. Thousands of times in our lives, a meticulously scripted but unseen wound healing drama plays, with cells serving as actors, extracellular matrix as the setting and growth factors as the means of communication. This article briefly reviews the cells involved in tissue repair, their signaling and proliferation mechanisms and the function of the extracellular matrix, then presents the actors and script for the three acts of the tissue repair drama. PMID:21220961

  9. DNA repair single-nucleotide polymorphisms in colorectal cancer and their role as modifiers of the effect of cigarette smoking and alcohol in the Singapore Chinese Health Study.

    PubMed

    Stern, Mariana C; Conti, David V; Siegmund, Kimberly D; Corral, Román; Yuan, Jian-Min; Koh, Woon-Puay; Yu, Mimi C

    2007-11-01

    Recently, we reported that among Singapore Chinese, cigarette smoking and alcohol drinking were independent risk factors for colorectal cancer. Both tobacco smoking and alcohol use are plausible colorectal cancer risk factors, partly due to their ability to induce mutations in the colorectal lumen. In the present study, we investigated the role in colorectal cancer of single-nucleotide polymorphisms in five DNA repair genes: XRCC1 (Arg(194)Trp and Arg(399)Gln), PARP (Val(762)Ala, Lys(940)Arg), XPD (Asp(312)Asn, Lys(751)Gln), OGG1 (Ser(326)Cys), and MGMT (Leu(84)Phe). We conducted this study within the Singapore Chinese Health Study, a population-based cohort of 63,257 middle-aged and older Singapore Chinese men and women enrolled between 1993 and 1998. Our study included 1,176 controls and 310 cases (180 colon and 130 rectum cancer). We observed a positive association between the PARP codon 940 Lys/Arg and Arg/Arg genotypes and colorectal cancer risk [odds ratio (OR), 1.8; 95% confidence interval (95% CI), 1.1-3.1], and an inverse association between the MGMT codon 84 Leu/Phe or Phe/Phe genotypes and colon cancer risk (OR, 0.6; 95% CI, 0.3-0.9), but not rectal cancer (test of heterogeneity by tumor site, P=0.027). We observed evidence that XRCC1 may modify the effects of smoking (interaction P=0.012). The effect of smoking among carriers of the Arg(194)-Gln(399) haplotype was OR=0.7 (95% CI, 0.4-1.1), whereas, among carriers of the Trp(194)-Arg(399) haplotype, it was OR=1.6 (95% CI, 1.1-2.5). We also observed a nonstatistically significant modification of XRCC1 on the effects of alcohol (P=0.245). Whereas alcohol had no effect among carriers of the codon 194 Arg/Arg (OR, 1.0; 95% CI, 0.6-1.7) or Arg/Trp genotypes (OR, 1.1; 95% CI, 0.6-1.9), there was a positive association among carriers of the Trp/Trp genotype (OR, 2.8; 95% CI, 1.0-8.1). Our results support a role for reactive oxygen species as relevant genotoxins that may account for the effects of both smoking

  10. 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.

  11. 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.

  12. 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…

  13. 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…

  14. 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…

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

    PubMed Central

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

    2004-01-01

    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 Å 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

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

    USDA-ARS?s Scientific Manuscript database

    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...

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

    DOEpatents

    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.

  18. Differential suppression of DNA repair deficiencies of Yeast rad50, mre11 and xrs2 mutants by EXO1 and TLC1 (the RNA component of telomerase).

    PubMed Central

    Lewis, L Kevin; Karthikeyan, G; Westmoreland, James W; Resnick, Michael A

    2002-01-01

    Rad50, Mre11, and Xrs2 form a nuclease complex that functions in both nonhomologous end-joining (NHEJ) and recombinational repair of DNA double-strand breaks (DSBs). A search for highly expressed cDNAs that suppress the DNA repair deficiency of rad50 mutants yielded multiple isolates of two genes: EXO1 and TLC1. Overexpression of EXO1 or TLC1 increased the resistance of rad50, mre11, and xrs2 mutants to ionizing radiation and MMS, but did not increase resistance in strains defective in recombination (rad51, rad52, rad54, rad59) or NHEJ only (yku70, sir4). Increased Exo1 or TLC1 RNA did not alter checkpoint responses or restore NHEJ proficiency, but DNA repair defects of yku70 and rad27 (fen) mutants were differentially suppressed by the two genes. Overexpression of Exo1, but not mutant proteins containing substitutions in the conserved nuclease domain, increased recombination and suppressed HO and EcoRI endonuclease-induced killing of rad50 strains. exo1 rad50 mutants lacking both nuclease activities exhibited a high proportion of enlarged, G2-arrested cells and displayed a synergistic decrease in DSB-induced plasmid:chromosome recombination. These results support a model in which the nuclease activity of the Rad50/Mre11/Xrs2 complex is required for recombinational repair, but not NHEJ. We suggest that the 5'-3' exo activity of Exo1 is able to substitute for Rad50/Mre11/Xrs2 in rescission of specific classes of DSB end structures. Gene-specific suppression by TLC1, which encodes the RNA subunit of the yeast telomerase complex, demonstrates that components of telomerase can also impact on DSB repair pathways. PMID:11805044

  19. A role for histone H2B during repair of UV-induced DNA damage in Saccharomyces cerevisiae.

    PubMed Central

    Martini, Emmanuelle M D; Keeney, Scott; Osley, Mary Ann

    2002-01-01

    To investigate the role of the nucleosome during repair of DNA damage in yeast, we screened for histone H2B mutants that were sensitive to UV irradiation. We have isolated a new mutant, htb1-3, that shows preferential sensitivity to UV-C. There is no detectable difference in bulk chromatin structure or in the number of UV-induced cis-syn cyclobutane pyrimidine dimers (CPD) between HTB1 and htb1-3 strains. These results suggest a specific effect of this histone H2B mutation in UV-induced DNA repair processes rather than a global effect on chromatin structure. We analyzed the UV sensitivity of double mutants that contained the htb1-3 mutation and mutations in genes from each of the three epistasis groups of RAD genes. The htb1-3 mutation enhanced UV-induced cell killing in rad1Delta and rad52Delta mutants but not in rad6Delta or rad18Delta mutants, which are defective in postreplicational DNA repair (PRR). When combined with other mutations that affect PRR, the histone mutation increased the UV sensitivity of strains with defects in either the error-prone (rev1Delta) or error-free (rad30Delta) branches of PRR, but did not enhance the UV sensitivity of a strain with a rad5Delta mutation. When combined with a ubc13Delta mutation, which is also epistatic with rad5Delta, the htb1-3 mutation enhanced UV-induced cell killing. These results suggest that histone H2B acts in a novel RAD5-dependent branch of PRR. PMID:11973294

  20. A Geometry-Based Cycle Slip Detection and Repair Method with Time-Differenced Carrier Phase (TDCP) for a Single Frequency Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) Receiver.

    PubMed

    Qian, Chuang; Liu, Hui; Zhang, Ming; Shu, Bao; Xu, Longwei; Zhang, Rufei

    2016-12-05

    As the field of high-precision applications based on carriers continues to expand, the development of low-cost, small, modular receivers and their application in diverse scenarios and situations with complex data quality has increased the requirements of carrier-phase data preprocessing. A new geometry-based cycle slip detection and repair method based on Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) is proposed. The method uses a Time-differenced Carrier Phase (TDCP) model, which eliminates the Inner-System Bias (ISB) between GPS and BDS, and it is conducive to the effective combination of GPS and BDS. It avoids the interference of the noise of the pseudo-range with cycle slip detection, while the cycle slips are preserved as integers. This method does not limit the receiver frequency number, and it is applicable to single-frequency data. The process is divided into two steps to detect and repair cycle slip. The first step is cycle slip detection, using the Improved Local Analysis Method (ILAM) to find satellites that have cycle slips; The second step is to repair the cycle slips, including estimating the float solution of changes in ambiguities at the satellites that have cycle slips with the least squares method and the integer solution of the cycle slips by rounding. In the process of rounding, in addition to the success probability, a decimal test is carried out to validate the result. Finally, experiments with filed test data are carried out to prove the effectiveness of this method. The results show that the detectable cycle slips number with GPS + BDS is much greater than that with GPS. The method can also detect the non-integer outliers while fixing the cycle slip. The maximum decimal bias in repair is less than that with GPS. It implies that this method takes full advantages of multi-system.

  1. A Geometry-Based Cycle Slip Detection and Repair Method with Time-Differenced Carrier Phase (TDCP) for a Single Frequency Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) Receiver

    PubMed Central

    Qian, Chuang; Liu, Hui; Zhang, Ming; Shu, Bao; Xu, Longwei; Zhang, Rufei

    2016-01-01

    As the field of high-precision applications based on carriers continues to expand, the development of low-cost, small, modular receivers and their application in diverse scenarios and situations with complex data quality has increased the requirements of carrier-phase data preprocessing. A new geometry-based cycle slip detection and repair method based on Global Position System (GPS) + BeiDou Navigation Satellite System (BDS) is proposed. The method uses a Time-differenced Carrier Phase (TDCP) model, which eliminates the Inner-System Bias (ISB) between GPS and BDS, and it is conducive to the effective combination of GPS and BDS. It avoids the interference of the noise of the pseudo-range with cycle slip detection, while the cycle slips are preserved as integers. This method does not limit the receiver frequency number, and it is applicable to single-frequency data. The process is divided into two steps to detect and repair cycle slip. The first step is cycle slip detection, using the Improved Local Analysis Method (ILAM) to find satellites that have cycle slips; The second step is to repair the cycle slips, including estimating the float solution of changes in ambiguities at the satellites that have cycle slips with the least squares method and the integer solution of the cycle slips by rounding. In the process of rounding, in addition to the success probability, a decimal test is carried out to validate the result. Finally, experiments with filed test data are carried out to prove the effectiveness of this method. The results show that the detectable cycle slips number with GPS + BDS is much greater than that with GPS. The method can also detect the non-integer outliers while fixing the cycle slip. The maximum decimal bias in repair is less than that with GPS. It implies that this method takes full advantages of multi-system. PMID:27929390

  2. 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

  3. The spectrum of congenital heart disease and outcomes after surgical repair among children with Turner syndrome: a single-center review.

    PubMed

    Cramer, Jonathan W; Bartz, Peter J; Simpson, Pippa M; Zangwill, Steven D

    2014-02-01

    Turner syndrome (TS), a genetic abnormality affecting 1 in 2,500 people, is commonly associated with congenital heart disease (CHD). However, the surgical outcomes for TS patients have not been well described. This study reviewed the spectrum of CHD in TS at the authors' center. The authors report outcomes after coarctation of the aorta (CoA) repair or staged palliation of hypoplastic left heart syndrome (HLHS) and then compare the surgical outcomes with those of non-TS patients undergoing like repair. This retrospective chart review was conducted at the Children's Hospital of Wisconsin from 1999 to 2011. Of the 173 patients with TS, 77 (44.5 %) were found to have CHD. Left-sided obstructive lesions were the most common. However, the spectrum of CHD was wide and included systemic and pulmonary venous abnormalities as well as abnormalities of the coronary arteries. In the comparative analysis of CoA repair, the TS patients younger than 60 days had longer aortic cross-clamp times (24 vs. 16 min; p = 0.001) and longer hospital stays (12 vs. 6 days; p ≤ 0.0001) than the non-TS patients. At the follow-up assessment after 8.8 ± 9.1 years, 17 % of the TS patients had hypertension, but no patient had required reintervention, and no deaths had occurred. Finally, three of the four TS patients with HLHS died within the first year. The spectrum of CHD within TS is wide and not limited to bicuspid aortic valve or CoA. Additionally, patients with TS undergoing CoA repair may have a more challenging early postoperative course but experience outcomes similar to those of non-TS patients. Finally, patients who have TS combined with HLHS remain a challenging population with generally poor survival.

  4. Endovascular Treatment of Complex Aortic Disease with Parallel-Graft Endovascular Aneurysm Repair. Retrospective Analysis of a Single Center Experience and Midterm Results.

    PubMed

    Roberto, Adovasio; Stefano, Chiarandini; Cristiano, Calvagna; Mario, D'Oria; Francesca, Zamolo; Damiano, Pipitone Marco; Giada, Sgorlon

    2017-09-21

    We sought to evaluate the midterm results of parallel-graft-endovascular aneurysm repair (pg-EVAR) for complex aortic anatomy in high-risk candidates for open surgical repair of abdominal aortic aneurism (AAA). Clinical and radiographic information on 35 patients treated by pg-EVAR between March 2010 and December 2015 was retrospectively reviewed and analyzed. All patients presented with symptomatic aneurysms and were treated within 3 days of clinical presentation. Primary endpoints included primary chimney-graft patency, overall survival, and freedom from all reintervention. Overall, 55 chimney grafts were placed into 47 renal arteries and 8 superior mesenteric arteries in 35 patients. An Endurant stent-graft was used as the main body component in all cases. At 36 months, primary chimney graft patency was 88%, overall survival of patients was 71% and the rate of freedom from all reintervention was 78%. Considering our mid-term results pg-EVAR seems to be a safe and effective treatment for patients with complex anatomies and at poor risk for open repair. Copyright © 2017. Published by Elsevier Inc.

  5. Prokaryotic Nucleotide Excision Repair

    PubMed Central

    Kisker, Caroline; Kuper, Jochen; Van Houten, Bennett

    2013-01-01

    Nucleotide excision repair (NER) has allowed bacteria to flourish in many different niches around the globe that inflict harsh environmental damage to their genetic material. NER is remarkable because of its diverse substrate repertoire, which differs greatly in chemical composition and structure. Recent advances in structural biology and single-molecule studies have given great insight into the structure and function of NER components. This ensemble of proteins orchestrates faithful removal of toxic DNA lesions through a multistep process. The damaged nucleotide is recognized by dynamic probing of the DNA structure that is then verified and marked for dual incisions followed by excision of the damage and surrounding nucleotides. The opposite DNA strand serves as a template for repair, which is completed after resynthesis and ligation. PMID:23457260

  6. Prokaryotic nucleotide excision repair.

    PubMed

    Kisker, Caroline; Kuper, Jochen; Van Houten, Bennett

    2013-03-01

    Nucleotide excision repair (NER) has allowed bacteria to flourish in many different niches around the globe that inflict harsh environmental damage to their genetic material. NER is remarkable because of its diverse substrate repertoire, which differs greatly in chemical composition and structure. Recent advances in structural biology and single-molecule studies have given great insight into the structure and function of NER components. This ensemble of proteins orchestrates faithful removal of toxic DNA lesions through a multistep process. The damaged nucleotide is recognized by dynamic probing of the DNA structure that is then verified and marked for dual incisions followed by excision of the damage and surrounding nucleotides. The opposite DNA strand serves as a template for repair, which is completed after resynthesis and ligation.

  7. Trans-vaginal anterior vaginal wall prolapse repair using a customized tension-free bell-shaped prolene mesh: A single-center experience with long-term functional analysis

    PubMed Central

    Arora, Sohrab; Kapoor, Rakesh; Yadav, Priyank; Mittal, Varun; Sureka, Sanjoy Kumar; Kapoor, Deepa

    2015-01-01

    Introduction: The existing literature shows that mesh reinforcement improves the anatomical success rate of cystocele repair. We report the long-term results of a custom bell-shaped mesh with simultaneous urethral support for the repair of cystocele. Materials and Methods: The present study was a single-center, single-surgeon case series of 36 patients. Only patients with Pelvic Organ Prolapse Quantification system (POP-Q) stage 2 and above were included in the study. Patients having rectocele or uterine/vault prolapse were excluded. Body of the mesh was used for reinforcement of the cystocele repair and two limbs were left tension free in the retropubic space. Patients were followed 3 monthly for the first year and yearly thereafter. Recurrence was defined as cystocele ≥stage 2 (Aa or Ba 0) any time after the first follow-up. Results: Mean patient age was 58.5 ± 6.2 years. The mean parity was 3.2 ± 1.6. Of 36 patients, 11 (30.5%) of the patients were POPQ stage 2, 15 (41.7%) were stage 3 and 10 (27.7%) were stage 4 cystocele. The mean follow-up period was 53.4 months, with 32 patients reporting for follow-up till date (88.9%). There was no bladder injury, no mesh erosion or infection. No patient required CIC (clean intermittent catheterization) or had stress urinary incontinence post-operatively at 5 years of follow-up. Conclusion: The bell-shaped mesh is a simple, effective and safe procedure in the surgical management of cystocele with excellent long-term outcome. PMID:26604446

  8. DNA Repair Deficiency in Neurodegeneration

    PubMed Central

    Jeppesen, Dennis Kjølhede; Bohr, Vilhelm A.; Stevnsner, Tinna

    2011-01-01

    Deficiency in repair of nuclear and mitochondrial DNA damage has been linked to several neurodegenerative disorders. Many recent experimental results indicate that the post-mitotic neurons are particularly prone to accumulation of unrepaired DNA lesions potentially leading to progressive neurodegeneration. Nucleotide excision repair is the cellular pathway responsible for removing helix-distorting DNA damage and deficiency in such repair is found in a number of diseases with neurodegenerative phenotypes, including Xeroderma Pigmentosum and Cockayne syndrome. The main pathway for repairing oxidative base lesions is base excision repair, and such repair is crucial for neurons given their high rates of oxygen metabolism. Mismatch repair corrects base mispairs generated during replication and evidence indicates that oxidative DNA damage can cause this pathway to expand trinucleotide repeats, thereby causing Huntington’s disease. Single-strand breaks are common DNA lesions and are associated with the neurodegenerative diseases, ataxia-oculomotor apraxia-1 and spinocerebellar ataxia with axonal neuropathy-1. DNA double-strand breaks are toxic lesions and two main pathways exist for their repair: homologous recombination and non-homologous end-joining. Ataxia telangiectasia and related disorders with defects in these pathways illustrate that such defects can lead to early childhood neurodegeneration. Aging is a risk factor for neurodegeneration and accumulation of oxidative mitochondrial DNA damage may be linked with the age-associated neurodegenerative disorders Alzheimer’s disease, Parkinson’s disease and amyotrophic lateral sclerosis. Mutation in the WRN protein leads to the premature aging disease Werner syndrome, a disorder that features neurodegeneration. In this article we review the evidence linking deficiencies in the DNA repair pathways with neurodegeneration. PMID:21550379

  9. Longitudinal Long-term Magnetic Resonance Imaging and Clinical Follow-up After Single-Row Arthroscopic Rotator Cuff Repair: Clinical Superiority of Structural Tendon Integrity.

    PubMed

    Heuberer, Philipp R; Smolen, Daniel; Pauzenberger, Leo; Plachel, Fabian; Salem, Sylvia; Laky, Brenda; Kriegleder, Bernhard; Anderl, Werner

    2017-05-01

    The number of arthroscopic rotator cuff surgeries is consistently increasing. Although generally considered successful, the reported number of retears after rotator cuff repair is substantial. Short-term clinical outcomes are reported to be rarely impaired by tendon retears, whereas to our knowledge, there is no study documenting long-term clinical outcomes and tendon integrity after arthroscopic rotator cuff repair. To investigate longitudinal long-term repair integrity and clinical outcomes after arthroscopic rotator cuff reconstruction. Case series; Level of evidence, 4. Thirty patients who underwent arthroscopic rotator cuff repair with suture anchors for a full-tendon full-thickness tear of the supraspinatus or a partial-tendon full-thickness tear of the infraspinatus were included. Two and 10 years after initial arthroscopic surgery, tendon integrity was analyzed using magnetic resonance imaging (MRI). The University of California, Los Angeles (UCLA) score and Constant score as well as subjective questions regarding satisfaction with the procedure and return to normal activity were used to evaluate short- and long-term outcomes. At the early MRI follow-up, 42% of patients showed a full-thickness rerupture, while 25% had a partial rerupture, and 33% of tendons remained intact. The 10-year MRI follow-up (129 ± 11 months) showed 50% with a total rerupture, while the other half of the tendons were partially reruptured (25%) or intact (25%). The UCLA and Constant scores significantly improved from preoperatively (UCLA total: 50.6% ± 20.2%; Constant total: 44.7 ± 10.5 points) to 2 years (UCLA total: 91.4% ± 16.0% [ P < .001]; Constant total: 87.8 ± 15.3 points [ P < .001]) and remained significantly higher after 10 years (UCLA total: 89.7% ± 15.9% [ P < .001]; Constant total: 77.5 ± 15.6 points [ P < .001]). The Constant total score and Constant strength subscore, but not the UCLA score, were also significantly better at 10 years postoperatively in patients

  10. Flavonoids and DNA Repair in Prostate Cancer

    DTIC Science & Technology

    2005-12-01

    There is in vitro evidence that some flavonoids such as myricetin and baicalin will stimulate DNA repair (3, 4). Flavonoid concentrations used in...Enzymol. 335: 308-316. 4. Chen, X., Nishida, H. & Konishi, T. (2003) Baicalin promoted the repair of DNA single strand breakage caused by H2O2 in

  11. The Wave Flap: A Single-Stage, Modified Nasal Sidewall Rotation Flap for the Repair of Defects Involving the Mid-Alar Groove.

    PubMed

    Bryan, Zachary T; Garrett, Algin B; Lavigne, Kerry; Trace, Anthony; Maher, Ian A

    2016-02-01

    Reconstruction of defects straddling the alar groove presents the dual challenges of resurfacing the nasal sidewall and alar subunits while simultaneously recreating the alar groove. The wave flap (WF) is a modified, medially based, nasal sidewall rotation flap that uses locally recruited tissue from the nasal sidewall to facilitate color and texture match and permit camouflage of scars. To detail a surgical repair for defects in the horizontally oriented middle third of the alar groove. This retrospective case series describes a technique for repair of defects involving the alar groove. Using postoperative photographs, outcomes were assessed by blinded noninvestigator dermatologist raters using the Observer Scar Assessment Scale. Between February 2012 and June 2013, 10 patients were reconstructed using a WF design. Subjective assessment of scar vascularity, pigment, pliability, relief, and thickness by 3 independent reviewers yielded an overall cosmesis score of 11.1 (out of 50). No complications were noted. The WF provides an excellent reconstructive option for Mohs defects of the middle third of the alar groove by recruiting local tissue and permitting maximum scar camouflage. A well-designed and executed WF provides cosmetically exceptional results for defects of the alar groove.

  12. Single nucleotide polymorphisms of nucleotide excision repair pathway are significantly associated with outcomes of platinum-based chemotherapy in lung cancer.

    PubMed

    Song, Xiao; Wang, Shiming; Hong, Xuan; Li, Xiaoying; Zhao, Xueying; Huai, Cong; Chen, Hongyan; Gao, Zhiqiang; Qian, Ji; Wang, Jiucun; Han, Baohui; Bai, Chunxue; Li, Qiang; Wu, Junjie; Lu, Daru

    2017-09-18

    Nucleotide excision repair (NER) pathway plays critical roles in repairing DNA disorders caused by platinum. To comprehensively understand the association between variants of NER and clinical outcomes of platinum-based chemotherapy, 173 SNPs in 27 genes were selected to evaluate association with toxicities and efficiency in 1004 patients with advanced non-small cell lung cancer. The results showed that consecutive significant signals were observed in XPA, RPA1, POLD1, POLD3. Further subgroup analysis showed that GTF2H4 presented consecutive significant signals in clinical benefit among adenocarcimoma. In squamous cell carcinoma, rs4150558, rs2290280, rs8067195 were significantly associated with anemia, rs3786136 was significantly related to thrombocytopenia, ERCC5 presented consecutive significant signals in response rate. In patients receiving TP regimen, significant association presented in neutropenia, thrombocytopenia and gastrointestinal toxicity. Association with anemia and neutropenia were found in GP regimen. rs4150558 showed significant association with anemia in NP regimen. In patients > 58, ERCC5 showed consecutive significant signals in gastrointestinal toxicity. Survival analysis showed SNPs in POLD2, XPA, ERCC6 and POLE were significantly associated with progression free survival, SNPs in GTF2H4, ERCC6, GTF2HA, MAT1, POLD1 were significantly associated with overall survival. This study suggests SNPs in NER pathway could be potential predictors for clinical outcomes of platinum-based chemotherapy among NSCLC.

  13. Aortic aneurysm repair - endovascular

    MedlinePlus

    ... Endovascular aneurysm repair - aorta; AAA repair - endovascular; Repair - aortic aneurysm - endovascular ... leaking or bleeding. You may have an abdominal aortic aneurysm that is not causing any symptoms or problems. ...

  14. Eye muscle repair - discharge

    MedlinePlus

    ... Lazy eye repair - discharge; Strabismus repair - discharge; Extraocular muscle surgery - discharge ... You or your child had eye muscle repair surgery to correct eye muscle ... term for crossed eyes is strabismus. Children most often ...

  15. 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 ...

  16. The combined effects of single-nucleotide polymorphisms, tobacco products, and ethanol on normal resting blood mononuclear cells.

    PubMed

    Cederblad, Lena; Thunberg, Ulf; Engström, Mats; Castro, Juan; Rutqvist, Lars Erik; Laytragoon-Lewin, Nongnit

    2013-05-01

    Tobacco and ethanol consumption are crucial factors in the development of various diseases including cancer. In this investigation, we evaluated the combined effects of a number of single nucleotide polymorphisms (SNPs), with ethanol and tobacco products on healthy individuals. Pure nicotine, cigarette smoke extract, and Swedish snuff (snus) extract were used. The effects were examined by means of in vitro cell cycle progression and cell death of peripheral blood mononuclear cells (PBMCs) obtained from healthy donors. After 3 days, in vitro, resting PBMCs entered the S and G2 stage in the presence of 100 µM nicotine. The PBMCs only proceeded to S stage, in the presence of 0.2% ethanol. The nicotine- and ethanol-induced normal cell cycle progression correlated to a number of SNPs in the IL12RB2, Rad 52, XRCC2, P53, CCND3, and ABCA1 genes. Certain SNPs in Caspases 8, IL12RB2, Rad 52, MMP2, and MDM2 genes appeared to significantly influence the effects of EtOH-, snus-, and snus + EtOH-induced cell death. Importantly, the highest degree of cell death was observed in the presence of smoke + EtOH. The amount of cell death under this treatment condition also correlated to specific SNPs, located in the MDM2, ABCA1, or GASC1 genes. Cigarette smoke in combination with ethanol strongly induced massive cell death. Long-term exposure to smoke and ethanol could provoke chronic inflammation, and this could be the initiation of disease including the development of cancer at various sites.

  17. 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

  18. INTERNAL REPAIR OF PIPELINES

    SciTech Connect

    Robin Gordon; Bill Bruce; Nancy Porter; Mike Sullivan; Chris Neary

    2003-05-01

    The two broad categories of deposited weld metal repair and fiber-reinforced composite 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 repairs and for fiber-reinforced composite repair. To date, all of the experimental work pertaining to the evaluation of potential repair methods has focused on fiber-reinforced composite repairs. Hydrostatic testing was also conducted on four pipeline sections with simulated corrosion damage: two with composite liners and two without.

  19. 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.

  20. An alternative eukaryotic DNA excision repair pathway.

    PubMed Central

    Freyer, G A; Davey, S; Ferrer, J V; Martin, A M; Beach, D; Doetsch, P W

    1995-01-01

    DNA lesions induced by UV light, cyclobutane pyrimidine dimers, and (6-4)pyrimidine pyrimidones are known to be repaired by the process of nucleotide excision repair (NER). However, in the fission yeast Schizosaccharomyces pombe, studies have demonstrated that at least two mechanisms for excising UV photo-products exist; NER and a second, previously unidentified process. Recently we reported that S. pombe contains a DNA endonuclease, SPDE, which recognizes and cleaves at a position immediately adjacent to cyclobutane pyrimidine dimers and (6-4)pyrimidine pyrimidones. Here we report that the UV-sensitive S. pombe rad12-502 mutant lacks SPDE activity. In addition, extracts prepared from the rad12-502 mutant are deficient in DNA excision repair, as demonstrated in an in vitro excision repair assay. DNA repair activity was restored to wild-type levels in extracts prepared from rad12-502 cells by the addition of partially purified SPDE to in vitro repair reaction mixtures. When the rad12-502 mutant was crossed with the NER rad13-A mutant, the resulting double mutant was much more sensitive to UV radiation than either single mutant, demonstrating that the rad12 gene product functions in a DNA repair pathway distinct from NER. These data directly link SPDE to this alternative excision repair process. We propose that the SPDE-dependent DNA repair pathway is the second DNA excision repair process present in S. pombe. PMID:7623848

  1. Genomic approaches to DNA repair and mutagenesis.

    PubMed

    Wyrick, John J; Roberts, Steven A

    2015-12-01

    DNA damage is a constant threat to cells, causing cytotoxicity as well as inducing genetic alterations. The steady-state abundance of DNA lesions in a cell is minimized by a variety of DNA repair mechanisms, including DNA strand break repair, mismatch repair, nucleotide excision repair, base excision repair, and ribonucleotide excision repair. The efficiencies and mechanisms by which these pathways remove damage from chromosomes have been primarily characterized by investigating the processing of lesions at defined genomic loci, among bulk genomic DNA, on episomal DNA constructs, or using in vitro substrates. However, the structure of a chromosome is heterogeneous, consisting of heavily protein-bound heterochromatic regions, open regulatory regions, actively transcribed genes, and even areas of transient single stranded DNA. Consequently, DNA repair pathways function in a much more diverse set of chromosomal contexts than can be readily assessed using previous methods. Recent efforts to develop whole genome maps of DNA damage, repair processes, and even mutations promise to greatly expand our understanding of DNA repair and mutagenesis. Here we review the current efforts to utilize whole genome maps of DNA damage and mutation to understand how different chromosomal contexts affect DNA excision repair pathways. Copyright © 2015 Elsevier B.V. All rights reserved.

  2. Genomic Approaches to DNA repair and Mutagenesis

    PubMed Central

    Wyrick, John J.; Roberts, Steven A.

    2015-01-01

    DNA damage is a constant threat to cells, causing cytotoxicity as well as inducing genetic alterations. The steady-state abundance of DNA lesions in a cell is minimized by a variety of DNA repair mechanisms, including DNA strand break repair, mismatch repair, nucleotide excision repair, base excision repair, and ribonucleotide excision repair. The efficiencies and mechanisms by which these pathways remove damage from chromosomes have been primarily characterized by investigating the processing of lesions at defined genomic loci, among bulk genomic DNA, on episomal DNA constructs, or using in vitro substrates. However, the structure of a chromosome is heterogeneous, consisting of heavily protein-bound heterochromatic regions, open regulatory regions, actively transcribed genes, and even areas of transient single stranded DNA. Consequently, DNA repair pathways function in a much more diverse set of chromosomal contexts than can be readily assessed using previous methods. Recent efforts to develop whole genome maps of DNA damage, repair processes, and even mutations promise to greatly expand our understanding of DNA repair and mutagenesis. Here we review the current efforts to utilize whole genome maps of DNA damage and mutation to understand how different chromosomal contexts affect DNA excision repair pathways. PMID:26411877

  3. 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)

  4. Dorsal onlay graft urethroplasty using penile skin or buccal mucosa for repair of bulbar urethral stricture: results of a prospective single center study.

    PubMed

    Raber, Marco; Naspro, Richard; Scapaticci, Emanuele; Salonia, Andrea; Scattoni, Vincenzo; Mazzoccoli, Bruno; Guazzoni, Giorgio; Rigatti, Patrizio; Montorsi, Francesco

    2005-12-01

    To compare the outcomes of dorsal onlay graft urethroplasty using penile skin (PS) or buccal mucosa (BM) free grafts in the repair of adult bulbourethral strictures. From January 1998 to March 2003, 30 patients with bulbar urethral strictures underwent urethral reconstruction with PS (17) or with BM free graft (13). Follow-up was done at 6, 12 and 18 months postoperatively, and every year subsequently. Success was defined as normalization of IPSS and a stable Q(max) value >20 ml/s. Any further instrumentation for stricture recurrence was considered a failure. Mean follow-up was 51 months (20-74). The overall success rate was 80% (85% in the BM and 76% in the PS group). Improvement of uroflowmetry, IPSS and QoL did not show a significant difference between the two groups. A significant improvement of the orgasmic function domain of the IIEF was found in patients treated with a PS graft. Post-operative complications were lip hypoesthesia (30%), retraction of the ventral skin of the penis (7%), post-voiding dribbling (8% with BM graft, and 7%, with PS graft). Six patients, 2 with BM (15%) and 4 with PS graft patch (24%) required further treatment due to stricture recurrence. Results of PS or BM graft are comparable at 18 month follow-up, although orgasmic function is significantly improved in patients receiving a PS graft. Nevertheless, with extended follow-up, the use of PS seems to be associated with a higher failure rate.

  5. The gastrointestinal manifestation of constitutional mismatch repair deficiency syndrome: from a single adenoma to polyposis-like phenotype and early onset cancer.

    PubMed

    Levi, Z; Kariv, R; Barnes-Kedar, I; Goldberg, Y; Half, E; Morgentern, S; Eli, B; Baris, H N; Vilkin, A; Belfer, R G; Niv, Y; Elhasid, R; Dvir, R; Abu-Freha, N; Cohen, S

    2015-11-01

    Data on the clinical presentation of constitutional mismatch repair deficiency syndrome (CMMRD) is accumulating. However, as the extraintestinal manifestations are often fatal and occur at early age, data on the systematic evaluation of the gastrointestinal tract is scarce. Here we describe 11 subjects with verified biallelic carriage and who underwent colonoscopy, upper endoscopy and small bowel evaluation. Five subjects were symptomatic and in six subjects the findings were screen detected. Two subjects had colorectal cancer and few adenomatous polyps (19, 20 years), three subjects had polyposis-like phenotype (13, 14, 16 years), four subjects had few adenomatous polyps (8, 12-14 years) and two subjects had no polyps (both at age 6). Of the three subjects in the polyposis-like group, two subjects had already developed high-grade dysplasia or cancer and one subject had atypical juvenile polyps suggesting juvenile polyposis. Three out of the five subjects that underwent repeated exams had significant findings during short interval. The gastrointestinal manifestations of CMMRD are highly dependent upon age of examination and highly variable. The polyps may also resemble juvenile polyposis. Intensive surveillance according to current guidelines is mandatory. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  6. Meiotic DNA double-strand break repair requires two nucleases, MRN and Ctp1, to produce a single size class of Rec12 (Spo11)-oligonucleotide complexes.

    PubMed

    Milman, Neta; Higuchi, Emily; Smith, Gerald R

    2009-11-01

    Programmed DNA double-strand breaks (DSBs) in meiosis are formed by Spo11 (Rec12 in fission yeast), a topoisomerase II-like protein, which becomes covalently attached to DNA 5' ends. For DSB repair through homologous recombination, the protein must be removed from these DNA ends. We show here that Rec12 is endonucleolytically removed from DSB ends attached to a short oligonucleotide (Rec12-oligonucleotide complex), as is Spo11 in budding yeast. Fission yeast, however, has only one size class of Rec12-oligonucleotide complexes, whereas budding yeast has two size classes, suggesting different endonucleolytic regulatory mechanisms. Rec12-oligonucleotide generation strictly requires Ctp1 (Sae2 nuclease homolog), the Rad32 (Mre11) nuclease domain, and Rad50 of the MRN complex. Surprisingly, Nbs1 is not strictly required, indicating separable roles for the MRN subunits. On the basis of these and other data, we propose that Rad32 nuclease has the catalytic site for Rec12-oligonucleotide generation and is activated by Ctp1, which plays an additional role in meiotic recombination.

  7. Association between single nucleotide polymorphisms (SNPs) of XRCC2 and XRCC3 homologous recombination repair genes and triple-negative breast cancer in Polish women.

    PubMed

    Smolarz, Beata; Makowska, Marianna; Samulak, Dariusz; Michalska, Magdalena M; Mojs, Ewa; Wilczak, Maciej; Romanowicz, Hanna

    2015-05-01

    XRCC2 and XRCC3 genes involved in homologous recombination repair (HRR) of DNA and in the maintenance of the genome integrity play a crucial role in protecting against mutations that lead to cancer. The aim of the present work was to evaluate associations between the risk of triple-negative breast cancer (TNBC) and polymorphisms in the genes, encoding for two key proteins of HRR: XRCC2 Arg188His (c. 563 G>A; rs3218536, Genbank Accession Number NT 007914) and XRCC3 Thr241Met (c. 722 C>T; rs861539, Genbank Accession Number NT 026437). The polymorphisms of the XRCC2 and XRCC3 were investigated by PCR-RFLP in 70 patients with TNBC and 70 age- and sex-matched non-cancer controls. In the present work, a relationship was identified between XRCC2 Arg188His polymorphism and the incidence of triple-negative breast cancer. The 188His allele and 188His/His homozygous variant increased cancer risk. An association was confirmed between XRCC2 Arg188His and XRCC3 Thr241Met polymorphisms and TNBC progression, assessed by the degree of lymph node metastases and histological grades. In conclusion, XRCC2 Arg188His and XRCC3 Thr241Met polymorphisms may be regarded as predictive factors of triple-negative breast cancer in female population.

  8. Arthroscopic Rotator Cuff Repair: Indication and Technique.

    PubMed

    Gilotra, Mohit; O'Brien, Michael J; Savoie, Felix H

    2016-01-01

    Shoulder arthroscopy and rotator cuff repair techniques are frequently used by most practicing orthopaedic surgeons. A thorough patient history and physical examination can often confirm the presence of a rotator cuff tear, and imaging can be used to evaluate the extent of the injury. The indication for rotator cuff repair is a painful shoulder refractory to nonsurgical management. Arthroscopic techniques, including capsular and coracohumeral ligament releases to decrease tension on the repair, facilitate successful rotator cuff repair. Biomechanically, a double-row transosseous-equivalent rotator cuff repair provides excellent results for medium-size rotator cuff tears. Larger, retracted rotator cuff tears may be better repaired with oblique convergence sutures and a medial single-row rotator cuff repair. The biology of healing, the preservation of blood supply, and the trephination of the bony healing bed are essential parts of all rotator cuff repair procedures. Protection of the rotator cuff repair with an abduction sling for 4 to 8 weeks postoperatively and the delay of active motion until early healing has occurred will improve outcomes.

  9. Elucidating the digital control mechanism for DNA damage repair with the p53–Mdm2 system: single cell data analysis and ensemble modelling

    PubMed Central

    Ogunnaike, Babatunde A

    2005-01-01

    Recent experimental evidence about DNA damage response using the p53–Mdm2 system has raised some fundamental questions about the control mechanism employed. In response to DNA damage, an ensemble of cells shows a damped oscillation in p53 expression whose amplitude increases with increased DNA damage—consistent with ‘analogue’ control. Recent experimental results, however, show that the single cell response is a series of discrete pulses in p53; and with increase in DNA damage, neither the height nor the duration of the pulses change, but the mean number of pulses increase—consistent with ‘digital’ control. Here we present a system engineering model that uses published data to elucidate this mechanism and resolve the dilemma of how digital behaviour at the single cell level can manifest as analogue ensemble behaviour. First, we develop a dynamic model of the p53–Mdm2 system that produces non-oscillatory responses to a stress signal. Second, we develop a probability model of the distribution of pulses in a cell population, and combine the two with the simplest digital control algorithm to show how oscillatory responses whose amplitudes grow with DNA damage can arise from single cell behaviour in which each single pulse response is independent of the extent of DNA damage. A stochastic simulation of the hypothesized control mechanism reproduces experimental observations remarkably well. PMID:16849229

  10. Elucidating the digital control mechanism for DNA damage repair with the p53-Mdm2 system: single cell data analysis and ensemble modelling.

    PubMed

    Ogunnaike, Babatunde A

    2006-02-22

    Recent experimental evidence about DNA damage response using the p53-Mdm2 system has raised some fundamental questions about the control mechanism employed. In response to DNA damage, an ensemble of cells shows a damped oscillation in p53 expression whose amplitude increases with increased DNA damage--consistent with 'analogue' control. Recent experimental results, however, show that the single cell response is a series of discrete pulses in p53; and with increase in DNA damage, neither the height nor the duration of the pulses change, but the mean number of pulses increase--consistent with 'digital' control. Here we present a system engineering model that uses published data to elucidate this mechanism and resolve the dilemma of how digital behaviour at the single cell level can manifest as analogue ensemble behaviour. First, we develop a dynamic model of the p53-Mdm2 system that produces non-oscillatory responses to a stress signal. Second, we develop a probability model of the distribution of pulses in a cell population, and combine the two with the simplest digital control algorithm to show how oscillatory responses whose amplitudes grow with DNA damage can arise from single cell behaviour in which each single pulse response is independent of the extent of DNA damage. A stochastic simulation of the hypothesized control mechanism reproduces experimental observations remarkably well.

  11. 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.

  12. 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.

  13. 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.

  14. Unraveling DNA repair in human: molecular mechanisms and consequences of repair defect.

    PubMed

    Tuteja, N; Tuteja, R

    2001-01-01

    Cellular genomes are vulnerable to an array of DNA-damaging agents, of both endogenous and environmental origin. Such damage occurs at a frequency too high to be compatible with life. As a result cell death and tissue degeneration, aging and cancer are caused. To avoid this and in order for the genome to be reproduced, these damages must be corrected efficiently by DNA repair mechanisms. Eukaryotic cells have multiple mechanisms for the repair of damaged DNA. These repair systems in humans protect the genome by repairing modified bases, DNA adducts, crosslinks and double-strand breaks. The lesions in DNA are eliminated by mechanisms such as direct reversal, base excision and nucleotide excision. The base excision repair eliminates single damaged-base residues by the action of specialized DNA glycosylases and AP endonucleases. Nucleotide excision repair excises damage within oligomers that are 25 to 32 nucleotides long. This repair utilizes many proteins to remove the major UV-induced photoproducts from DNA, as well as other types of modified nucleotides. Different DNA polymerases and ligases are utilized to complete the separate pathways. The double-strand breaks in DNA are repaired by mechanisms that involve DNA protein kinase and recombination proteins. The defect in one of the repair protein results in three rare recessive syndromes: xeroderma pigmentosum, Cockayne syndrome, and trichothiodystrophy. This review describes the biochemistry of various repair processes and summarizes the clinical features and molecular mechanisms underlying these disorders.

  15. Laparoscopic herniorrhaphy. Transabdominal preperitoneal floor repair.

    PubMed

    Felix, E L; Michas, C A; McKnight, R L

    1994-02-01

    The purpose of this study was to evaluate the results of a laparoscopic transabdominal preperitoneal (TAPP) approach to inguinal hernia repair which dissected the entire inguinal floor and repaired the indirect, direct, and femoral areas in all patients without tension. In our series, 183 patients had 205 hernia repairs and were followed for more than 6 months. Of this group, 128 hernias were indirect, 55 direct, 22 pantaloon, 26 recurrent, and 22 bilateral. All 12 females and the first 11 males had a single-buttress repair with polypropylene mesh. The other 160 male patients had a double-buttress repair. With median follow-up of 12 months, ranging from 6 to 21 months, no recurrences were found. Patients returned to normal activity in an average of 1 week. Dissection and buttressing of the entire inguinal floor with mesh appeared to solve the problem of early recurrence first seen in laparoscopic herniorrhaphy.

  16. Databases and Bioinformatics Tools for the Study of DNA Repair

    PubMed Central

    Milanowska, Kaja; Rother, Kristian; Bujnicki, Janusz M.

    2011-01-01

    DNA is continuously exposed to many different damaging agents such as environmental chemicals, UV light, ionizing radiation, and reactive cellular metabolites. DNA lesions can result in different phenotypical consequences ranging from a number of diseases, including cancer, to cellular malfunction, cell death, or aging. To counteract the deleterious effects of DNA damage, cells have developed various repair systems, including biochemical pathways responsible for the removal of single-strand lesions such as base excision repair (BER) and nucleotide excision repair (NER) or specialized polymerases temporarily taking over lesion-arrested DNA polymerases during the S phase in translesion synthesis (TLS). There are also other mechanisms of DNA repair such as homologous recombination repair (HRR), nonhomologous end-joining repair (NHEJ), or DNA damage response system (DDR). This paper reviews bioinformatics resources specialized in disseminating information about DNA repair pathways, proteins involved in repair mechanisms, damaging agents, and DNA lesions. PMID:22091405

  17. Is percutaneous repair better than open repair in acute Achilles tendon rupture?

    PubMed

    Henríquez, Hugo; Muñoz, Roberto; Carcuro, Giovanni; Bastías, Christian

    2012-04-01

    Open repair of Achilles tendon rupture has been associated with higher levels of wound complications than those associated with percutaneous repair. However, some studies suggest there are higher rerupture rates and sural nerve injuries with percutaneous repair. We compared the two types of repairs in terms of (1) function (muscle strength, ankle ROM, calf and ankle perimeter, single heel rise tests, and work return), (2) cosmesis (length scar, cosmetic appearance), and (3) complications. We retrospectively reviewed 32 surgically treated patients with Achilles rupture: 17 with percutaneous repair and 15 with open repair. All patients followed a standardized rehabilitation protocol. The minimum followup was 6 months (mean, 18 months; range, 6-48 months). We observed similar values of plantar flexor strength, ROM, calf and ankle perimeter, and single heel raising test between the groups. Mean time to return to work was longer for patients who had open versus percutaneous repair (5.6 months versus 2.8 months). Mean scar length was greater in the open repair group (9.5 cm versus 2.9 cm). Cosmetic appearance was better in the percutaneous group. Two wound complications and one rerupture were found in the open repair group. One case of deep venous thrombosis occurred in the percutaneous repair group. All complications occurred before 6 months after surgery. We identified no patients with nerve injury. Percutaneous repair provides function similar to that achieved with open repair, with a better cosmetic appearance, a lower rate of wound complications, and no apparent increase in the risk of rerupture. Level III, therapeutic study. See Guidelines for Authors for a complete description of levels of evidence.

  18. A single-surgeon randomized trial comparing sutures, N-butyl-2-cyanoacrylate and human fibrin glue for mesh fixation during primary inguinal hernia repair

    PubMed Central

    Testini, Mario; Lissidini, Germana; Poli, Elisabetta; Gurrado, Angela; Lardo, Domenica; Piccinni, Giuseppe

    2010-01-01

    , p = 0.03; fibrin glue v. N-butyl-2-cyanoacrylate, p = 0.30). Conclusion The use of human fibrin glue or N-butyl-2-cyanoacrylate is better tolerated than sutures in tension-free inguinal open repair using the plug and mesh technique in terms of overall immediate results, and there is a better trend in the long-term data. PMID:20507786

  19. Collision Repair Campaign

    EPA Pesticide Factsheets

    The Collision Repair Campaign targets meaningful risk reduction in the Collision Repair source category to reduce air toxic emissions in their communities. The Campaign also helps shops to work towards early compliance with the Auto Body Rule.

  20. 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 ...

  1. Inguinal hernia repair

    MedlinePlus

    ... This repair can be done with open or laparoscopic surgery. You and your surgeon can discuss which type ... the repair, the cuts are stitched closed. In laparoscopic surgery: The surgeon makes three to five small cuts ...

  2. Effects of single dose and regular intake of green tea (Camellia sinensis) on DNA damage, DNA repair, and heme oxygenase-1 expression in a randomized controlled human supplementation study.

    PubMed

    Ho, Cyrus K; Choi, Siu-wai; Siu, Parco M; Benzie, Iris F F

    2014-06-01

    Regular intake of green tea (Camellia sinensis) lowers DNA damage in humans, but molecular mechanisms of genoprotection are not clear. Protection could be via direct antioxidant effects of tea catechins, but, paradoxically, catechins have pro-oxidant activity in vitro, and it is hypothesized that mechanisms relate to redox-sensitive cytoprotective adaptations. We investigated this hypothesis, focusing particularly on effects on the DNA repair enzyme human oxoguanine glycosylase 1 (hOGG1), and heme oxygenase-1, a protein that has antioxidant and anti-inflammatory effects. A randomized, placebo-controlled, human supplementation study of crossover design was performed. Subjects (n = 16) took a single dose (200 mL of 1.5%, w/v) and 7-days of (2 × 200 mL 1%, w/v per day) green tea (with water as control treatment). Lymphocytic DNA damage was ∼30% (p < 0.001) lower at 60 and 120 min after the single dose and in fasting samples collected after 7-day tea supplementation. Lymphocytic hOGG1 activity was higher (p < 0.0001) at 60 and 120 min after tea ingestion. Significant increases (p < 0.0005) were seen in hOGG1 activity and heme oxygenase-1 after 7 days. Results indicate that molecular triggering of redox-sensitive cytoprotective adaptations and posttranslational changes affecting hOGG1 occur in vivo in response to both a single dose and regular intake of green tea, and contribute to the observed genoprotective effects of green tea.

  3. Transconjunctival entropion repair - the backdoor approach.

    PubMed

    Kreis, Andreas J; Shafi, Fariha; Madge, Simon N

    2013-10-01

    To present a modified transconjunctival approach for involutional entropion repair. This study is a retrospective consecutive single surgeon case series using a transconjunctival approach for involutional lower lid entropion (ILLE) repair. Eleven eyes were operated for involution entropion with 9 cases of complete resolution. Two patients required further Jones' retractor plication. Transconjunctival involutional lower lid entropion repair is a time-efficient, safe, and efficacious technique. The scar free technique described leads to full restoration of lower lid anatomy. In contrast to other reports we found a relatively low rate of recurrence on follow-up.

  4. Pallet repair and salvage

    Treesearch

    Richard E. Frost; Hollis R. Large

    1975-01-01

    Efficient unit-load handling with permanent pallets requires a well-organized pallet repair program. To provide basic infomation on pallet damage that could be used in establishing repair standards, we inspected a total of 1700 damaged pallets at four repair facilities. All damage was recorded by type, severity, and location. This survey determined that missing...

  5. Cell cycle-dependent spatial segregation of telomerase from sites of DNA damage.

    PubMed

    Ouenzar, Faissal; Lalonde, Maxime; Laprade, Hadrien; Morin, Geneviève; Gallardo, Franck; Tremblay-Belzile, Samuel; Chartrand, Pascal

    2017-08-07

    Telomerase can generate a novel telomere at DNA double-strand breaks (DSBs), an event called de novo telomere addition. How this activity is suppressed remains unclear. Combining single-molecule imaging and deep sequencing, we show that the budding yeast telomerase RNA (TLC1 RNA) is spatially segregated to the nucleolus and excluded from sites of DNA repair in a cell cycle-dependent manner. Although TLC1 RNA accumulates in the nucleoplasm in G1/S, Pif1 activity promotes TLC1 RNA localization in the nucleolus in G2/M. In the presence of DSBs, TLC1 RNA remains nucleolar in most G2/M cells but accumulates in the nucleoplasm and colocalizes with DSBs in rad52Δ cells, leading to de novo telomere additions. Nucleoplasmic accumulation of TLC1 RNA depends on Cdc13 localization at DSBs and on the SUMO ligase Siz1, which is required for de novo telomere addition in rad52Δ cells. This study reveals novel roles for Pif1, Rad52, and Siz1-dependent sumoylation in the spatial exclusion of telomerase from sites of DNA repair. © 2017 Ouenzar et al.

  6. [Comparative study of the repair of full thickness tear of the supraspinatus by means of "single row" or "suture bridge" techniques].

    PubMed

    Arroyo-Hernández, M; Mellado-Romero, M A; Páramo-Díaz, P; Martín-López, C M; Cano-Egea, J M; Vilá Y Rico, J

    2015-01-01

    The purpose of this study is to analyze if there is any difference between the arthroscopic reparation of full-thickness supraspinatus tears with simple row technique versus suture bridge technique. We accomplished a retrospective study of 123 patients with full-thickness supraspinatus tears between January 2009 and January 2013 in our hospital. There were 60 simple row reparations, and 63 suture bridge ones. The mean age in the simple row group was 62.9, and in the suture bridge group was 63.3 years old. There were more women than men in both groups (67%). All patients were studied using the Constant test. The mean Constant test in the suture bridge group was 76.7, and in the simple row group was 72.4. We have also accomplished a statistical analysis of each Constant item. Strength was higher in the suture bridge group, with a significant statistical difference (p 0.04). The range of movement was also greater in the suture bridge group, but was not statistically significant. Suture bridge technique has better clinical results than single row reparations, but the difference is not statistically significant (p = 0.298).

  7. 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.

  8. 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.

  9. 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.

  10. Oxidatively induced DNA damage and its repair in cancer.

    PubMed

    Dizdaroglu, Miral

    2015-01-01

    Oxidatively induced DNA damage is caused in living organisms by endogenous and exogenous reactive species. DNA lesions resulting from this type of damage are mutagenic and cytotoxic and, if not repaired, can cause genetic instability that may lead to disease processes including carcinogenesis. Living organisms possess DNA repair mechanisms that include a variety of pathways to repair multiple DNA lesions. Mutations and polymorphisms also occur in DNA repair genes adversely affecting DNA repair systems. Cancer tissues overexpress DNA repair proteins and thus develop greater DNA repair capacity than normal tissues. Increased DNA repair in tumors that removes DNA lesions before they become toxic is a major mechanism for development of resistance to therapy, affecting patient survival. Accumulated evidence suggests that DNA repair capacity may be a predictive biomarker for patient response to therapy. Thus, knowledge of DNA protein expressions in normal and cancerous tissues may help predict and guide development of treatments and yield the best therapeutic response. DNA repair proteins constitute targets for inhibitors to overcome the resistance of tumors to therapy. Inhibitors of DNA repair for combination therapy or as single agents for monotherapy may help selectively kill tumors, potentially leading to personalized therapy. Numerous inhibitors have been developed and are being tested in clinical trials. The efficacy of some inhibitors in therapy has been demonstrated in patients. Further development of inhibitors of DNA repair proteins is globally underway to help eradicate cancer.

  11. Conventional surgery and transcatheter closure via surgical transapical approach for paravalvular leak repair in high-risk patients: results from a single-centre experience.

    PubMed

    Taramasso, Maurizio; Maisano, Francesco; Latib, Azeem; Denti, Paolo; Guidotti, Andrea; Sticchi, Alessandro; Panoulas, Vasileios; Giustino, Gennaro; Pozzoli, Alberto; Buzzatti, Nicola; Cota, Linda; De Bonis, Michele; Montorfano, Matteo; Castiglioni, Alessandro; Blasio, Andrea; La Canna, Giovanni; Colombo, Antonio; Alfieri, Ottavio

    2014-10-01

    Paravalvular leaks (PVL) occur in up to 17% of all surgically implanted prosthetic valves. Re-operation is associated with high morbidity and mortality. Transcatheter closure via a surgical transapical approach (TAp) is an emerging alternative for selected high-risk patients with PVL. The aim of this study was to compare the in-hospital outcomes of patients who underwent surgery and TA-closure for PVL in our single-centre experience. From October 2000 to June 2013, 139 patients with PVL were treated in our Institution. All the TA procedures were performed under general anaesthesia in a hybrid operative room: in all but one case an Amplatzer Vascular Plug III device was utilized. Hundred and thirty-nine patients with PVL were treated: 122 patients (87.3%) underwent surgical treatment (68% mitral PVL; 32% aortic PVL) and 17 patients (12.2%) underwent a transcatheter closure via a surgical TAp approach (all the patients had mitral PVL; one case had combined mitral and aortic PVLs); in 35% of surgical patients and in 47% of TAp patients, multiple PVLs were present. The mean age was 62.5 ± 11 years; the Logistic EuroScore was 15.4 ± 3. Most of the patients were in New York Heart Association (NYHA) functional class III-IV (57%). Symptomatic haemolysis was present in 35% of the patients, and it was particularly frequent in the TAp (70%). Many patients had >1 previous cardiac operation (46% overall and 82% of TAp patients were at their second of re-operation). Acute procedural success was 98%. In-hospital mortality was 9.3%; no in-hospital deaths occurred in patients treated through a TAp approach. All the patients had less than moderate residual valve regurgitation after the procedure. Surgical treatment was identified as a risk factor for in-hospital death at univariate analysis (OR: 8, 95% CI: 1.8-13; P = 0.05). Overall actuarial survival at follow-up was 39.8 ± 7% at 12 years and it was reduced in patients who had >1 cardiac re-operation (42 ± 8 vs. 63 ± 6% at 9

  12. An analysis of single nucleotide polymorphisms of 125 DNA repair genes in the Texas genome-wide association study of lung cancer with a replication for the XRCC4 SNPs

    PubMed Central

    Yu, Hongping; Zhao, Hui; Wang, Li-E; Han, Younghun; Chen, Wei V.; Amos, Christopher I.; Rafnar, Thorunn; Sulem, Patrick; Stefansson, Kari; Landi, Maria Teresa; Caporaso, Neil; Albanes, Demetrius; Thun, Michael; McKay, James D.; Brennan, Paul; Wang, Yufei; Houlston, Richard S; Spitz, Margaret R.; Wei, Qingyi

    2011-01-01

    DNA repair genes are important for maintaining genomic stability and limiting carcinogenesis. We analyzed all single nucleotide polymorphisms (SNPs) of 125 DNA repair genes covered by the Illumina HumanHap300 (v1.1) BeadChips in a previously conducted genome-wide association study (GWAS) of 1,154 lung cancer cases and 1,137 controls and replicated the top-hits of XRCC4 SNPs in an independent set of 597 cases and 611 controls in Texas populations. We found that six of 20 XRCC4 SNPs were associated with a decreased risk of lung cancer with a P value of 0.01 or lower in the discovery dataset, of which the most significant SNP was rs10040363 (P for allelic test = 4.89 ×10−4). Moreover, the data in this region allowed us to impute a potentially functional SNP rs2075685 (imputed P for allelic test = 1.3 ×10−3). A luciferase reporter assay demonstrated that the rs2075685G>T change in the XRCC4 promoter increased expression of the gene. In the replication study of rs10040363, rs1478486, rs9293329, and rs2075685, however, only rs10040363 achieved a borderline association with a decreased risk of lung cancer in a dominant model (adjusted OR = 0.80, 95% CI = 0.62–1.03, P = 0.079). In the final combined analysis of both the Texas GWAS discovery and replication datasets, the strength of the association was increased for rs10040363 (adjusted OR = 0.77, 95% CI = 0.66–0.89, Pdominant = 5×10−4 and P for trend = 5×10−4) and rs1478486 (adjusted OR = 0.82, 95% CI = 0.71 −0.94, Pdominant = 6×10−3 and P for trend = 3.5×10−3). Finally, we conducted a meta-analysis of these XRCC4 SNPs with available data from published GWA studies of lung cancer with a total of 12,312 cases and 47,921 controls, in which none of these XRCC4 SNPs was associated with lung cancer risk. It appeared that rs2075685, although associated with increased expression of a reporter gene and lung cancer risk in the Texas populations, did not have an effect on lung cancer risk in other populations

  13. RNA-templated DNA repair

    PubMed Central

    Storici, Francesca; Bebenek, Katarzyna; Kunkel, Thomas A.; Gordenin, Dmitry A.; Resnick, Michael A.

    2007-01-01

    RNA can act as a template for DNA synthesis in the reverse transcription of retroviruses and retrotransposons1 and in the elongation of telomeres2. Despite its abundance in the nucleus, there has been no evidence for a direct role of RNA as a template in the repair of any chromosomal DNA lesions, including DNA double-strand breaks (DSBs), which are repaired in most organisms by homologous recombination or by non-homologous end joining3. An indirect role for RNA in DNA repair, following reverse transcription and formation of a complementary DNA, has been observed in the non-homologous joining of DSB ends4,5. In the yeast Saccharomyces cerevisiae, in which homologous recombination is efficient3, RNA was shown to mediate recombination, but only indirectly through a cDNA intermediate6,7 generated by the reverse transcriptase function of Ty retrotransposons in Ty particles in the cytoplasm8. Although pairing between duplex DNA and single-strand (ss)RNA can occur in vitro9,10 and in vivo11, direct homologous exchange of genetic information between RNA and DNA molecules has not been observed. We show here that RNA can serve as a template for DNA synthesis during repair of a chromosomal DSB in yeast. The repair was accomplished with RNA oligonucleotides complementary to the broken ends. This and the observation that even yeast replicative DNA polymerases such as α and δ can copy short RNA template tracts in vitro demonstrate that RNA can transfer genetic information in vivo through direct homologous interaction with chromosomal DNA. PMID:17429354

  14. AAPSM repair utilizing transparent etch stop layer

    NASA Astrophysics Data System (ADS)

    Taylor, Darren; Cangemi, Michael; Lassiter, Matthew; Cangemi, Marc; Poortinga, Eric

    2004-12-01

    Repair of etched quartz defects on AAPSM products negatively affect manufacturability in the mask shop. Currently there are few solutions to repair etched quartz defects, two of these include mechanical removal or a combination of topography mapping and FIB milling of the defect. Both of the above methods involve large capital investments specifically for etched quartz repair. The method presented in this study readily repairs etched quartz without the need to purchase additional tools for AAPSM repair. Photronics' Advanced Materials Program has developed a transparent etch stop layer (TESL) integrated into the binary blank for the purpose of building AAPSM products with a high yield component. This etch stop layer is located under a layer of sputtered SiO2 deposited to 180° for a given lithography wavelength. These blanks can be used for a variety of etched quartz applications including cPSM and CPL. Photronics has developed software that reads in defect locations from automatic inspection tools and the jobdeck. A "repair" layer is created for the defect file and the plate is then re-exposed on the mask lithography tool. The defects are then etched away using the etch stop to control the phase of the surrounding trench. The repair method was tested using programmed defect masks from single etched 193nm AAPSM technologies. Inspection, SEM, AIMS and profilometry results will be shown.

  15. DNA excision repair in permeable human fibroblasts

    SciTech Connect

    Kaufmann, W.K.; Bodell, W.J.; Cleaver, J.E.

    1983-01-01

    U.v. irradiation of confluent human fibroblasts activated DNA repair, aspects of which were characterized in the cells after they were permeabilized. Incubation of intact cells for 20 min between irradiation and harvesting was necessary to obtain a maximum rate of reparative DNA synthesis. Cells harvested immediately after irradiation before repair was initiated displayed only a small stimulation of DNA synthesis, indicating that permeable cells have a reduced capacity to recognize pyrimidine dimers and activate repair. The distribution of sizes of DNA strands labeled during 10 min of reparative DNA synthesis resembled that of parental DNA. However, during a 60-min incubation of permeable cells at 37 degrees C, parental DNA and DNA labeled by reparative DNA synthesis were both cleaved to smaller sizes. Cleavage also occurred in unirradiated cells, indicating that endogenous nuclease was active during incubation. Repair patches synthesized in permeable cells displayed increased sensitivity to digestion by micrococcal nuclease. However, the change in sensitivity during a chase with unlabeled DNA precursors was small, suggesting that reassembly of nucleosome structure at sites of repair was impaired. To examine whether this deficiency was due to a preponderance of incomplete or unligated repair patches, 3H-labeled (repaired) DNA was purified, then digested with exonuclease III and nuclease S1 to probe for free 3' ends and single-stranded regions. About 85% of the (3H)DNA synthesized during a 10-min pulse resisted digestion, suggesting that a major fraction of the repair patches that were filled were also ligated. U.v. light-activated DNA synthesis in permeable cells, therefore, appears to represent the continuation of reparative gap-filling at sites of excision repair activated within intact cells. Gap-filling and ligation were comparatively efficient processes in permeable cells.

  16. Retinal detachment repair

    MedlinePlus

    Scleral buckling; Vitrectomy; Pneumatic retinopexy; Laser retinopexy; Rhegmatogenous retinal detachment repair ... it meets the hole in the retina. Scleral buckling can be done using numbing medicine while you ...

  17. Attitudes, practice, and experience of German dentists regarding repair restorations.

    PubMed

    Kanzow, Philipp; Hoffmann, Robin; Tschammler, Claudia; Kruppa, Jochen; Rödig, Tina; Wiegand, Annette

    2017-05-01

    The aim of the present study was to perform a representative survey among German dentists about attitudes, practice, and experience regarding single-tooth repair restorations. An anonymous questionnaire was designed and mailed to all registered dentists in Lower Saxony (n = 6600). Twenty-eight percent were returned (n = 1852), and n = 1805 could be analyzed. Statistical analyses were done by Wilcoxon signed-rank tests, Kruskal-Wallis tests, and ordered logistic regressions (p < 0.05). Only 2.2 % of the dentists declared to never perform repair restorations. Composite restorations were repaired significantly more often than all other materials. Frequency of performing repair restorations was partially associated to dentist-related factors. The decision for repairing a restoration was dependent on several tooth- and restoration-associated variables. The main indications for repair were the partial loss of restoration or adjacent tooth structure as well as chipping and endodontic access cavities of crowns. Repair restorations were mostly done with composite using various different preconditioning techniques. Overall patients' acceptance was reported to be high. Most of the dentists considered repair restorations as permanent restoration with a moderate to high longevity. Estimated success of repair restorations depended significantly on the dentists' experiences (frequency and techniques of repair restorations). Repair restorations were often performed and were well accepted by dentists and patients, but indications for repair restorations as well as applied materials and techniques varied distinctly. Repairs of single-tooth restorations are well accepted and frequently performed, but indications, techniques, and materials require further research.

  18. 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.

  19. In vivo effect of DNA repair on the transition frequency produced from a single O6-methyl- or O6-n-butyl-guanine in a T:G base pair.

    PubMed

    Chambers, R W; Sledziewska-Gojska, E; Hirani-Hojatti, S

    1988-08-01

    We have previously reported some effects of DNA repair on the transition frequencies produced by an O6-methyl-guanine (MeG) or an O6-n-butyl-guanine (BuG) paired with C at the first position of the third codon in gene G of bacteriophage phi X174 form I' DNA (Chambers et al. 1985). We now report experiments in which the transition is produced from T:MeG or T:BuG, instead of C:MeG or C:BuG, located at this site. The site-modified DNAs were transfected into cells with normal DNA repair as well as into cells with repair defects (uvrA, uvrB, uvrC, recA, uvrArecA). The lysates were screened for phage carrying the expected transition using a characteristic change in phenotype. The data demonstrate that the transition frequency from T:BuG is low (0.3% of total phage progeny) in cells with normal repair (Escherichia coli AB1157) and increases 7-fold in uvrA cells (E. coli AB1886). A similar increase is seen in uvrB and uvrC cells (AB1885, AB1884). These data, like our previous data, indicate BuG is repaired primarily by excision. In contrast to this, the transition frequency from T:MeG is high (5 +/- 2%) in cells with normal repair. After induction of alkyl transfer repair in E. coli AB1157, the transition frequency goes up 5-fold. Compared with cells with normal repair, the transition frequency goes up 2-fold in uvrA, uvrB and uvrC cells; it goes up 1.5-fold in recA cells (E. coli AB2463). The data reinforce our earlier conclusion that MeG is repaired primarily by alkyl transfer, but the ABC excinuclease as well as RecA protein inhibit this repair process.(ABSTRACT TRUNCATED AT 250 WORDS)

  20. 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…

  1. Imperforate anus repair

    MedlinePlus

    ... repair URL of this page: //medlineplus.gov/ency/article/002926.htm Imperforate anus repair To use the sharing features on this page, ... done. Why the Procedure is Performed ... blood clots, infection Risks of this procedure include: Damage to the urethra (tube that carries urine out ...

  2. Chain Saw Repair.

    ERIC Educational Resources Information Center

    Taylor, Mark; Helbling, Wayne

    This curriculum is designed to supplement the Comprehensive Small Engine Repair guide by covering in detail all aspects of chain saw repair. The publication contains materials for both teacher and student and is written in terms of student performance using measurable objectives. The course includes six units. Each unit contains some or all of the…

  3. Suture versus preperitoneal polypropylene mesh for elective umbilical hernia repairs.

    PubMed

    Berger, Rachel L; Li, Linda T; Hicks, Stephanie C; Liang, Mike K

    2014-12-01

    Repair of primary ventral hernias (PVH) such as umbilical hernias is a common surgical procedure. There is a paucity of risk-adjusted data comparing suture versus mesh repair of these hernias. We compared preperitoneal polypropylene (PP) repair versus suture repair for elective umbilical hernia repair. A retrospective review of all elective open PVH repairs at a single institution from 2000-2010 was performed. Only patients with suture or PP repair of umbilical hernias were included. Univariate analysis was conducted and propensity for treatment-adjusted multivariate logistic regression. There were 442 elective open PVH repairs performed; 392 met our inclusion criteria. Of these patients, 126 (32.1%) had a PP repair and 266 (67.9%) underwent suture repair. Median (range) follow-up was 60 mo (1-143). Patients who underwent PP repair had more surgical site infections (SSIs; 19.8% versus 7.9%, P < 0.01) and seromas (14.3% versus 4.1%, P < 0.01). There was no difference in recurrence (5.6% versus 7.5%, P = 0.53). On propensity score-adjusted multivariate analysis, we found that body mass index (odds ratio [OR], 1.10) and smoking status (OR, 2.3) were associated with recurrence. Mesh (OR, 2.34) and American Society of Anesthesiologists (OR, 1.95) were associated with SSI. Only mesh (OR, 3.41) was associated with seroma formation. Although there was a trend toward more recurrence with suture repair in our study, this was not statistically significant. Mesh repair was associated with more SSI and seromas. Further prospective randomized controlled trial is needed to clarify the role of suture and mesh repair in PVH. Copyright © 2014 Elsevier Inc. All rights reserved.

  4. Flexor Tendon Repair With Looped Suture: 1 Versus 2 Knots.

    PubMed

    Gil, Joseph A; Skjong, Christian; Katarincic, Julia A; Got, Christopher

    2016-03-01

    To assess the strength of flexor tendon repair with looped suture. We hypothesized that, after passing the intact looped suture in the desired repair configuration, splitting the loop and tying 2 independent knots would increase the strength of flexor tendon repair. Thirty-two flexor tendons were harvested and were sharply transected in zone II. The tendons were repaired with a 4-strand core suture repair using 3-0 looped nonabsorbable nylon suture. The harvested tendons were randomly assigned and repaired with either a 1- or a 2-knot construct. The repaired flexor tendons were fixed in a servohydraulic material testing system and were loaded to failure either with uniaxial tension or cyclically. The average force at failure was 43 N for the 1-knot repair and 28 N for the 2-knot repair. The mode of failure of 15 of the flexor tendon repairs that were cyclically loaded to failure was suture pull-out. The average number of cycles and force in cyclic testing that caused failure of flexor tendon repairs was 134 cycles and 31 N for tendons repaired with looped 3-0 suture tied with 1 knot and 94 cycles and 33 N for tendons repaired with looped 3-0 suture tied with 2 knots. Our hypothesis was disproved by the results of this study. This study suggests that, when using looped suture, tying 2 independent knots instead of tying a single knot does not increase the strength of the flexor tendon repair. Copyright © 2016 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  5. 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

  6. Laparoscopic repair of recurrent groin hernias.

    PubMed

    Felix, E L; Michas, C; McKnight, R L

    1994-06-01

    Between November 1991 and May 1993, 54 recurrent groin hernias were laparoscopically repaired in 50 patients. Forty-eight were men and two were women. Forty-six recurrent hernias were unilateral and four bilateral. Twenty-five were direct, 19 indirect, 10 pantaloon, and two had a femoral component. In only 10 patients was the contralateral side normal. In 27 patients, the other side had been previously repaired, and in 13 they had a new contralateral hernia. A transabdominal preperitoneal technique was used to dissect and repair the entire floor in all patients. A single sheet of polypropylene mesh was used in the repair of the women patients, and a double-buttress technique with the first sheet slitted for the cord was used for the men. Patients were examined every 3 months for the first year and at 6-month intervals thereafter. Follow-up ranged from 1 to 18 months with a mean of 8 months. No patient was lost to follow-up, and no recurrence was observed. Patients returned to normal activity in an average of 1 week. Seroma, which resolved spontaneously, was the most common complication. The overall short-term results suggested that a laparoscopic mesh buttressed repair of recurrent groin hernias is technically feasible and can eliminate early rerecurrence of the hernia so commonly seen after repair of recurrent hernias.

  7. Differential genetic interactions between Sgs1, DNA-damage checkpoint components and DNA repair factors in the maintenance of chromosome stability.

    PubMed

    Doerfler, Lillian; Harris, Lorena; Viebranz, Emilie; Schmidt, Kristina H

    2011-10-31

    Genome instability is associated with human cancers and chromosome breakage syndromes, including Bloom's syndrome, caused by inactivation of BLM helicase. Numerous mutations that lead to genome instability are known, yet how they interact genetically is poorly understood. We show that spontaneous translocations that arise by nonallelic homologous recombination in DNA-damage-checkpoint-defective yeast lacking the BLM-related Sgs1 helicase (sgs1Δ mec3Δ) are inhibited if cells lack Mec1/ATR kinase. Tel1/ATM, in contrast, acts as a suppressor independently of Mec3 and Sgs1. Translocations are also inhibited in cells lacking Dun1 kinase, but not in cells defective in a parallel checkpoint branch defined by Chk1 kinase. While we had previously shown that RAD51 deletion did not inhibit translocation formation, RAD59 deletion led to inhibition comparable to the rad52Δ mutation. A candidate screen of other DNA metabolic factors identified Exo1 as a strong suppressor of chromosomal rearrangements in the sgs1Δ mutant, becoming even more important for chromosomal stability upon MEC3 deletion. We determined that the C-terminal third of Exo1, harboring mismatch repair protein binding sites and phosphorylation sites, is dispensable for Exo1's roles in chromosomal rearrangement suppression, mutation avoidance and resistance to DNA-damaging agents. Our findings suggest that translocations between related genes can form by Rad59-dependent, Rad51-independent homologous recombination, which is independently suppressed by Sgs1, Tel1, Mec3 and Exo1 but promoted by Dun1 and the telomerase-inhibitor Mec1. We propose a model for the functional interaction between mitotic recombination and the DNA-damage checkpoint in the suppression of chromosomal rearrangements in sgs1Δ cells.

  8. 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

  9. Mismatch repair proteins collaborate with methyltransferases in the repair of O6-methylguanine

    PubMed Central

    Rye, Peter T.; Delaney, James C.; Netirojjanakul, Chawita; Sun, Dana X.; Liu, Jenny Z.; Essigmann, John M.

    2010-01-01

    DNA repair is essential for combatting the adverse effects of damage to the genome. One example of base damage is O6-methylguanine (O6mG), which stably pairs with thymine during replication and thereby creates a promutagenic O6mG:T mismatch. This mismatch has also been linked with cellular toxicity. Therefore, in the absence of repair, O6mG:T mismatches can lead to cell death or result in G:C→A:T transition mutations upon the next round of replication. Cysteine thiolate residues on the Ada and Ogt methyltransferase (MTase) proteins directly reverse the O6mG base damage to yield guanine. When a cytosine is opposite the lesion, MTase repair restores a normal G:C pairing. However, if replication past the lesion has produced an O6mG:T mismatch, MTase conversion to a G:T mispair must still undergo correction to avoid mutation. Two mismatch repair pathways in E. coli that convert G:T mispairs to native G:C pairings are methyl-directed mismatch repair (MMR) and very short patch repair (VSPR). This work examined the possible roles that proteins in these pathways play in coordination with the canonical MTase repair of O6mG:T mismatches. The possibility of this repair network was analyzed by probing the efficiency of MTase repair of a single O6mG residue in cells deficient in individual mismatch repair proteins (Dam, MutH, MutS, MutL, or Vsr). We found that MTase repair in cells deficient in Dam or MutH showed wild-type levels of MTase repair. In contrast, cells lacking any of the VSPR proteins MutS, MutL, or Vsr showed a decrease in repair of O6mG by the Ada and Ogt MTases. Evidence is presented that the VSPR pathway positively influences MTase repair of O6mG:T mismatches, and assists the efficiency of restoring these mismatches to native G:C base pairs. PMID:17951114

  10. Flavonoids and DNA Repair in Prostate Cancer

    DTIC Science & Technology

    2004-12-01

    responsible to fill the gap created by the excision of 8-OHdG. There is in vitro evidence that some flavonoids such as myricetin and baicalin will...myricetin. Methods Enzymol., 335, 308-316. 4. Chen,X., Nishida,H., and Konishi,T. (2003) Baicalin promoted the repair of DNA single strand breakage caused by

  11. 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

  12. 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.

  13. Choreography of oxidative damage repair in mammalian genomes.

    PubMed

    Mitra, Sankar; Izumi, Tadahide; Boldogh, Istvan; Bhakat, Kishor K; Hill, Jeff W; Hazra, Tapas K

    2002-07-01

    The lesions induced by reactive oxygen species in both nuclear and mitochondrial genomes include altered bases, abasic (AP) sites, and single-strand breaks, all repaired primarily via the base excision repair (BER) pathway. Although the basic BER process (consisting of five sequential steps) could be reconstituted in vitro with only four enzymes, it is now evident that repair of oxidative damage, at least in mammalian cell nuclei, is more complex, and involves a number of additional proteins, including transcription- and replication-associated factors. These proteins may be required in sequential repair steps in concert with other cellular changes, starting with nuclear targeting of the early repair enzymes in response to oxidative stress, facilitation of lesion recognition, and access by chromatin unfolding via histone acetylation, and formation of metastable complexes of repair enzymes and other accessory proteins. Distinct, specific subclasses of protein complexes may be formed for repair of oxidative lesions in the nucleus in transcribed vs. nontranscribed sequences in chromatin, in quiescent vs. cycling cells, and in nascent vs. parental DNA strands in replicating cells. Characterizing the proteins for each repair subpathway, their signaling-dependent modifications and interactions in the nuclear as well as mitochondrial repair complexes, will be a major focus of future research in oxidative damage repair.

  14. 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.

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

    PubMed

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

    1991-10-01

    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.

  17. Nucleotide excision repair in Trypanosoma brucei: specialization of transcription-coupled repair due to multigenic transcription

    PubMed Central

    Machado, Carlos R; Vieira-da-Rocha, João P; Mendes, Isabela Cecilia; Rajão, Matheus A; Marcello, Lucio; Bitar, Mainá; Drummond, Marcela G; Grynberg, Priscila; Oliveira, Denise A A; Marques, Catarina; Van Houten, Ben; McCulloch, Richard

    2014-01-01

    Nucleotide excision repair (NER) is a highly conserved genome repair pathway acting on helix distorting DNA lesions. NER is divided into two subpathways: global genome NER (GG-NER), which is responsible for repair throughout genomes, and transcription-coupled NER (TC-NER), which acts on lesions that impede transcription. The extent of the Trypanosoma brucei genome that is transcribed is highly unusual, since most genes are organized in multigene transcription units, each transcribed from a single promoter. Given this transcription organization, we have addressed the importance of NER to T. brucei genome maintenance by performing RNAi against all predicted contributing factors. Our results indicate that TC-NER is the main pathway of NER repair, but only CSB, XPBz and XPG contribute. Moreover, we show that UV lesions are inefficiently repaired in T. brucei, perhaps due to preferential use of RNA polymerase translesion synthesis. RNAi of XPC and DDB was found to be lethal, and we show that these factors act in inter-strand cross-link repair. XPD and XPB appear only to act in transcription, not repair. This work indicates that the predominance of multigenic transcription in T. brucei has resulted in pronounced adaptation of NER relative to the host and may be an attractive drug target. PMID:24661334

  18. 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

  19. DNA repair within nucleosome cores of UV-irradiated human cells

    SciTech Connect

    Jensen, K.A.; Smerdon, M.J. )

    1990-05-22

    We have compared the distributions of repair synthesis and pyrimidine dimers (PD) in nucleosome core DNA during the early (fast) repair phase and the late (slow) repair phase of UV-irradiated human fibroblasts. As shown previously, repair synthesis is nonuniform in nucleosome core particles during the fast repair phase, and the distribution curve can be approximated by a model where repair synthesis occurs preferentially in the 5' and 3' end regions. In this report, we show that, during the slow repair phase, (3H)dThd-labeled repair patches are much more uniformly distributed in core DNA, although they appear to be preferentially located in sequences degraded slowly by exonuclease III. This change in distribution cannot be explained by an increase in patch size during slow repair, since the size of these patches actually decreases to about half the size measured during the fast repair phase. Furthermore, PD mapping within core DNA at the single-nucleotide level demonstrated that, at least within the 30-130-base region from the 5' end, there is little (or no) selective removal of PD during the fast repair phase. However, the nonuniform distribution of repair synthesis obtained during fast repair throughout most of the core DNA region (approximately 40-146 bases) is accounted for by the nonuniform distribution of PD in core DNA. The near-uniform distribution of repair synthesis observed during slow repair may result from more extensive nucleosome rearrangement and/or nucleosome modification during this phase.

  20. 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.

  1. 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.

  2. 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.

  3. Laser repairing of parts in metallurgical industries

    NASA Astrophysics Data System (ADS)

    Yang, Xichen; Wang, Yunshan; Zhao, Xin

    1999-09-01

    A new repair system for hardfacing of parts in metallurgical industries has been developed. The system can produce single pass quenching or cladding width of 10 - 35 mm, thickness of 0.5 - 10 mm. The wide range of powder materials can be deposited to provide hardfacing layers against wear, corrosion and oxidation. Comparing with welding and flame spraying, it presents clear advantages with low distortion, low dilution, low cost and small postclad machining. It has been successfully used to repair some of parts, for example, roll, drawing wire wheel in high speed wire, and so on.

  4. Biological consequences of formation and repair of complex DNA damage.

    PubMed

    Magnander, Karin; Elmroth, Kecke

    2012-12-31

    Endogenous processes or genotoxic agents can induce many types of single DNA damage (single-strand breaks, oxidized bases and abasic sites). In addition, ionizing radiation induces complex lesions such as double-strand breaks and clustered damage. To preserve the genomic stability and prevent carcinogenesis, distinct repair pathways have evolved. Despite this, complex DNA damage can cause severe problems and is believed to contribute to the biological consequences observed in cells exposed to genotoxic stress. In this review, the current knowledge of formation and repair of complex DNA damage is summarized and the risks and biological consequences associated with their repair are discussed. Copyright © 2012 Elsevier Ireland Ltd. All rights reserved.

  5. Hiatal hernia repair - slideshow

    MedlinePlus

    ... presentations/100028.htm Hiatal hernia repair - series—Normal anatomy To use the sharing features on ... Overview The esophagus runs through the diaphragm to the stomach. It functions to carry food from the mouth ...

  6. Ventral hernia repair

    MedlinePlus

    ... Philadelphia. PA: Elsevier Saunders; 2014:539-545. Nagle AP, Soper NJ. Laparoscopic ventral hernia repair. In: Khatri ... Support Get email updates Subscribe to RSS Follow us Disclaimers Copyright Privacy Accessibility Quality Guidelines Viewers & Players ...

  7. Hypospadias repair - discharge

    MedlinePlus

    ... JC, Brock JW. Repair of proximal hypospadias. In: Smith JA, Howards SS, Preminger GM, Dmochowski RR, eds. Hinman's ... commercial use must be authorized in writing by ADAM Health Solutions. About MedlinePlus Site Map FAQs Customer ...

  8. 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. ...

  9. 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 ...

  10. Meningocele repair - slideshow

    MedlinePlus

    ... ency/presentations/100128.htm Meningocele repair - series—Normal anatomy To use the sharing features on this page, ... Sinai Medical Center, Los Angeles and Department of Anatomy, University of California, San Francisco, CA. Review provided ...

  11. 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.

  12. Diaphragmatic hernia repair - slideshow

    MedlinePlus

    ... presentations/100014.htm Diaphragmatic hernia repair - series—Normal anatomy To use the sharing ... Overview The chest cavity includes the heart and lungs. The abdominal cavity includes the liver, the stomach, ...

  13. 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)

  14. Femoral hernia repair

    MedlinePlus

    ... medicine to relax you . Your surgeon makes a cut (incision) in your groin area. The hernia is ... wall. At the end of the repair, the cuts are stitched closed. In laparascopic surgery: The surgeon ...

  15. Pectus excavatum repair

    MedlinePlus

    Gottlieb LJ, Reid RR, Lee JC. Pediatric chest and trunk defects. In: Neligan PC, ed. Plastic Surgery . 3rd ed. Philadelphia, PA: Elsevier; 2013:chap 41. Lumpkins KM, Colombani P, Abdullah F. Repair ...

  16. Bone fracture repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100077.htm Bone fracture repair - series—Indications To use the sharing features ... Go to slide 4 out of 4 Overview Fractures of the bones are classified in a number ...

  17. Femur fracture repair - discharge

    MedlinePlus

    ... page: //medlineplus.gov/ency/patientinstructions/000166.htm Femur fracture repair - discharge To use the sharing features on this page, please enable JavaScript. You had a fracture (break) in the femur in your leg. It ...

  18. Tracheoesophageal fistula repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100103.htm Tracheoesophageal fistula repair - series—Normal anatomy To use the sharing ... Editorial team. Related MedlinePlus Health Topics Esophagus Disorders Fistulas Tracheal Disorders A.D.A.M., Inc. is ...

  19. Pectus excavatum repair - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100035.htm Pectus excavatum repair - series—Normal anatomy To use the sharing ... Go to slide 4 out of 4 Overview Pectus excavatum is a deformity of the front of the ...

  20. 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 ...

  1. Retinal detachment repair - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100132.htm Retinal detachment repair - series—Normal anatomy To use the ... to slide 6 out of 6 Overview The retina is the internal layer of the eye that ...

  2. Transconjunctival epiblepharon repair.

    PubMed

    Wladis, Edward J

    2014-01-01

    To document the use of a transconjunctival approach to lower eyelid epiblepharon repair. Retrospective chart review of all patients who underwent transconjunctival lower eyelid epiblepharon repair. Nine patients underwent repair via this approach. All patients experienced the resolution of their keratitis and cilia-cornea touch by a 3-month postoperative interval, and no patient developed a postoperative complication. Furthermore, no patient developed cutaneous scarring. Conventional approaches to lower eyelid epiblepharon repair have necessitated the creation of a skin and muscle flap, thus risking the development of scarring and a cosmetically unacceptable eyelid crease. This report documents the use of a transconjunctival approach for the management of this condition that avoids external incisions and provides excellent outcomes without scarring of the anterior lamella of the eyelid.

  3. 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

  4. Umbilical hernia repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100105.htm Umbilical hernia repair - series—Normal anatomy To use the sharing ... A.M. Editorial team. Related MedlinePlus Health Topics Hernia A.D.A.M., Inc. is accredited by ...

  5. Cleft lip repair - slideshow

    MedlinePlus

    ... presentations/100010.htm Cleft lip repair - series—Normal anatomy To use the sharing features on this page, ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  6. Carpal tunnel repair - slideshow

    MedlinePlus

    ... page: //medlineplus.gov/ency/presentations/100078.htm Carpal tunnel repair - series—Normal anatomy To use the sharing ... in the wrist and the wrist bones (carpal tunnel). Review Date 5/9/2015 Updated by: C. ...

  7. Rotator cuff repair - slideshow

    MedlinePlus

    ... presentations/100229.htm Rotator cuff repair - series—Normal anatomy To use the sharing features on this page, ... Bethesda, MD 20894 U.S. Department of Health and Human Services National Institutes of Health Page last updated: ...

  8. Repair Process Performance Analysis

    DTIC Science & Technology

    1988-05-01

    CRITICAL HURDLE W/S UNIT REPAIR COST : xx xx x x.xx CURRENT POSITION...NAME u/s MAXO(N ALC SOR INS CRITICAL HURDLE RANK UNIT REPAIR COST axxKXXX xi ilixiX xx xii xiiii xx Xiii iXi.ii *ON...GAIE PLAN GET WELL DATE-JUNE 19I1 NSN XXXX-XX- XXX -XXXx 7OTAL REQUIREENT :RPC: :RPV: - -..... -- ,---,° . I::""C I I ..... .....RPC: C ----: R

  9. Revision arthroscopic Bankart repair.

    PubMed

    Abouali, Jihad Alexander Karim; Hatzantoni, Katerina; Holtby, Richard; Veillette, Christian; Theodoropoulos, John

    2013-09-01

    Failed anterior shoulder stabilization procedures have traditionally been treated with open procedures. Recent advances in arthroscopic techniques have allowed for certain failed stabilization procedures to be treated by arthroscopic surgery. The aim of this systematic review was to determine the outcomes of revision arthroscopic Bankart repair. We searched Medline, Embase, and CINAHL (Cumulative Index to Nursing and Allied Health Literature) for articles on revision arthroscopic Bankart repairs. Key words included shoulder dislocation, anterior shoulder instability, revision surgery, and arthroscopic Bankart repair. Two reviewers selected studies for inclusion, assessed methodologic quality, and extracted data. We included 16 studies comprising 349 patients. All studies were retrospective (1 Level II study and 15 Level IV studies). The mean incidence of recurrent instability after revision arthroscopic Bankart repair was 12.7%, and the mean follow-up period was 35.4 months. The most common cause for failure of the primary surgeries was a traumatic injury (62.1%), and 85.1% of patients returned to playing sports. The reasons for failure of revision cases included glenohumeral bone loss, hyperlaxity, and return to contact sports. With proper patient selection, the outcomes of revision arthroscopic Bankart repair appear similar to those of revision open Bankart repair. Prospective, randomized clinical trials are required to confirm these findings. Level IV, systematic review of Level II and Level IV studies. Copyright © 2013 Arthroscopy Association of North America. Published by Elsevier Inc. All rights reserved.

  10. 77 FR 30053 - Repair Stations

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-05-21

    ...This action would amend the regulations for repair stations by revising the system of ratings, the repair station certification requirements, and the regulations on repair stations providing maintenance for air carriers. This action is necessary because many portions of the existing repair station regulations do not reflect current repair station aircraft maintenance and business practices, or advances in aircraft technology. These changes would modernize the regulations to keep pace with current industry standards and practices.

  11. 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

  12. Designing Hydrogel Adhesives for Corneal Wound Repair

    PubMed Central

    Grinstaff, Mark W.

    2013-01-01

    Today, corneal wounds are repaired using nylon sutures. Yet there are a number of complications associated with suturing the cornea, and thus there is interest in an adhesive to replace or supplement sutures in the repair of corneal wounds. We are designing and evaluating corneal adhesives prepared from dendrimers – single molecular weight, highly branched polymers. We have explored two strategies to form these ocular adhesives. The first involves a photocrosslinking reaction and the second uses a peptide ligation reactions to couple the individual dendrimers together to from the adhesive. These adhesives were successfully used to repair corneal perforations, close the flap produced in a LASIK procedure, and secure a corneal transplant. PMID:17889330

  13. Proximal Contact Repair of Complex Amalgam Restorations.

    PubMed

    Zguri, M N; Casey, J A; Jessup, J P; Vandewalle, K S

    2017-01-12

    The carving of a complex amalgam restoration may occasionally result in light proximal contact with the adjacent tooth. The purpose of this study was to investigate the strength of complex amalgam restorations repaired with a proximal slot amalgam preparation. Extracted human third molars of similar coronal size were sectioned 1 mm apical to the height of the contour using a saw and were randomly distributed into 9 groups of 10 teeth each. One pin was placed at each line angle of the flattened dentinal tooth surface. A metal matrix band was placed and an admixed alloy was condensed and carved to create a full crown contour but with a flat occlusal surface. A proximal slot was prepared with or without a retention groove and repaired using a single-composition spherical amalgam 15 minutes, 24 hours, one week, or six months after the initial crown condensation. The specimens were stored for 24 hours in 37°C water before fracture at the marginal ridge using a round-ended blade in a universal testing machine. The control group was not repaired. The mean maximum force in newtons and standard deviation were determined per group. Data were analyzed with a 2-way analysis of variance as well as Tukey and Dunnett tests (α=0.05). Significant differences were found between groups based on type of slot preparation (p=0.017) but not on time (p=0.327), with no significant interaction (p=0.152). No significant difference in the strength of the marginal ridge was found between any repair group and the unrepaired control group (p>0.076). The proximal repair strength of a complex amalgam restoration was not significantly different from an unrepaired amalgam crown. Placing a retention groove in the proximal slot preparation resulted in significantly greater fracture strength than a slot with no retention grooves. Time of repair had no significant effect on the strength of the repair.

  14. Performance of GFIS mask repair system for various mask materials

    NASA Astrophysics Data System (ADS)

    Aramaki, Fumio; Kozakai, Tomokazu; Matsuda, Osamu; Yasaka, Anto; Yoshikawa, Shingo; Kanno, Koichi; Miyashita, Hiroyuki; Hayashi, Naoya

    2014-10-01

    We have developed a new focused ion beam (FIB) technology using a gas field ion source (GFIS) for mask repair. Meanwhile, since current high-end photomasks do not have high durability in exposure nor cleaning, some new photomask materials are proposed. In 2012, we reported that our GFIS system had repaired a representative new material "A6L2". It is currently expected to extend the application range of GFIS technology for various new materials and various defect shapes. In this study, we repaired a single bridge, a triple bridge and a missing hole on a phase shift mask (PSM) of "A6L2", and also repaired single bridges on a binary mask of molybdenum silicide (MoSi) material "W4G" and a PSM of high transmittance material "SDC1". The etching selectivity between those new materials and quartz were over 4:1. There were no significant differences of pattern shapes on scanning electron microscopy (SEM) images between repair and non-repair regions. All the critical dimensions (CD) at repair regions were less than +/-3% of those at normal ones on an aerial image metrology system (AIMS). Those results demonstrated that GFIS technology is a reliable solution of repairing new material photomasks that are candidates for 1X nm generation.

  15. Repairability of aged resin composites mediated by different restorative systems.

    PubMed

    Lemos, Cleidiel Aa; Mauro, Sílvio J; de Campos, Renata A; Dos Santos, Paulo H; Machado, Lucas S; Fagundes, Ticiane C

    2016-04-01

    The aim of this study was to evaluate the shear bond strength of resin composite repairs with and without aging of the surface to be repaired, using different adhesive systems and resin composites. Ninety specimens were prepared: 10 for the Control Group (GC - without repair); 40 for Group I (GI - repairs after 7 days) and 40 for Group II (GII - repairs after 180 days). Groups I and II were divided into 4 subgroups of 10 specimens each, according to the adhesive system and composite resin used: A) Adper Scotch Bond Multipurpose + Filtek Z350 XT; B) Adper Single Bond Plus + Filtek Z350 XT; C) Adper Scotch Bond Multipurpose + Esthet-X; D) Adper Single Bond Plus + Esthet-X. The specimens were tested for shear strength in a universal testing machine. The results were analyzed by two-factor one-way ANOVA and Fisher's post hoc tests (alpha=0.05). The control group had better performance than the other groups. There was no significant difference when comparing different adhesive systems and composite resins. Repairs performed at 7 days were better than those performed at 180 days. The composite repairs decreased the mechanical strength of the restoration. Aging of the resin substrate may decrease repair bond strength over time, regardless of the type of adhesive systems and resin composites used.

  16. Factors affecting healing after arthroscopic rotator cuff repair

    PubMed Central

    Abtahi, Amir M; Granger, Erin K; Tashjian, Robert Z

    2015-01-01

    Rotator cuff repair has been shown to have good long-term results. Unfortunately, a significant proportion of repairs still fail to heal. Many factors, both patient and surgeon related, can influence healing after repair. Older age, larger tear size, worse muscle quality, greater muscle-tendon unit retraction, smoking, osteoporosis, diabetes and hypercholesterolemia have all shown to negatively influence tendon healing. Surgeon related factors that can influence healing include repair construct-single vs double row, rehabilitation, and biologics including platelet rich plasma and mesenchymal stem cells. Double-row repairs are biomechanically stronger and have better healing rates compared with single-row repairs although clinical outcomes are equivalent between both constructs. Slower, less aggressive rehabilitation programs have demonstrated improved healing with no negative effect on final range of motion and are therefore recommended after repair of most full thickness tears. Additionally no definitive evidence supports the use of platelet rich plasma or mesenchymal stem cells regarding improvement of healing rates and clinical outcomes. Further research is needed to identify effective biologically directed augmentations that will improve healing rates and clinical outcomes after rotator cuff repair. PMID:25793161

  17. 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.

  18. 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.

  19. 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

  20. 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.

  1. 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.

  2. Interactions between mutations for sensitivity to psoralen photoaddition (PSO) and to radiation (rad) in Saccharomyces cerevisiae

    SciTech Connect

    Henriques, J.A.P.; Moustacchi, E.

    1981-10-01

    The mode of interaction in haploid Saccharomyces cerevisiae of two PSO mutations with each other and with rad mutations affected in their excision resynthesis (rad3), error-prone (rad6), and deoxyribonucleic acid double-strand break (rad52) repair pathways was determined for various double mutant combinations. Survival data for 8-methoxypsoralen photoaddition, 254-nm ultraviolet light and gamma rays are presented. For 8-methoxypsoralen photoaddition, which induces both deoxyribonucleic acid interstrand cross-links and monoadditions, is synergistic to rad3. The PSO2 mutation, which is specifically sensitive to photoaddition of psoralens, is epistatic to rad3 and demonstrates a nonepistatic interaction with rad6 and rad52. rad3 and rad6, as well as rad6 and rad52, show synergistic interactions with each other, whereas rad3 is epistatic to rad52. Consequently, it is proposed that PSO1 and RAD3 genes govern steps in two independent pathways, the PSO1 activity leading to an intermediate which is repaired via the three independent pathways controlled by RAD6, RAD52, and PSO2 genes. Since pso1 interacts synergistically with rad3 and rad52 and epistatically with rad6 after uv radiation, the PSO1 gene appears to belong to the RAD6 group. For gamma ray sensitivity, pso1 is epistatic to rad6 and rad52, which suggests that this gene controls a step which is common to the two other independent pathways.

  3. Transcriptomic Approaches to Neural Repair

    PubMed Central

    Antunes-Martins, Ana; Chandran, Vijayendran; Costigan, Michael; Lerch, Jessica K.; Willis, Dianna E.; Tuszynski, Mark H.

    2015-01-01

    Understanding why adult CNS neurons fail to regenerate their axons following injury remains a central challenge of neuroscience research. A more complete appreciation of the biological mechanisms shaping the injured nervous system is a crucial prerequisite for the development of robust therapies to promote neural repair. Historically, the identification of regeneration associated signaling pathways has been impeded by the limitations of available genetic and molecular tools. As we progress into an era in which the high-throughput interrogation of gene expression is commonplace and our knowledge base of interactome data is rapidly expanding, we can now begin to assemble a more comprehensive view of the complex biology governing axon regeneration. Here, we highlight current and ongoing work featuring transcriptomic approaches toward the discovery of novel molecular mechanisms that can be manipulated to promote neural repair. SIGNIFICANCE STATEMENT Transcriptional profiling is a powerful technique with broad applications in the field of neuroscience. Recent advances such as single-cell transcriptomics, CNS cell type-specific and developmental stage-specific expression libraries are rapidly enhancing the power of transcriptomics for neuroscience applications. However, extracting biologically meaningful information from large transcriptomic datasets remains a formidable challenge. This mini-symposium will highlight current work using transcriptomic approaches to identify regulatory networks in the injured nervous system. We will discuss analytical strategies for transcriptomics data, the significance of noncoding RNA networks, and the utility of multiomic data integration. Though the studies featured here specifically focus on neural repair, the approaches highlighted in this mini-symposium will be of broad interest and utility to neuroscientists working in diverse areas of the field. PMID:26468186

  4. Significance of changes in residual stresses and mechanical properties due to SMAW repair of girth welds in linepipe

    SciTech Connect

    McGaughy, T.; Boyles, L.

    1990-10-31

    This program assessed the effects of SMAW repair welding on changes in surface residual stress distribution, fracture toughness and hardness around girth weld joints in linepipe. The following types of repair welds were studied: a part wall repair, a multiple part wall repair and full wall repair. The results were compared with a non-repaired weld sample. It was found that for the weld samples studied in this program, the full wall repair produced the most severe residual stress distribution followed by the multiple and single part wall repairs. The single repair only slightly increased the residual stress distribution when compared to the as-welded condition. Dramatic reductions in toughness were found in the multiple and full repairs due to coarse-grained regions produced during the repair operations. The single part wall repair exhibited an increase in toughness as a result of the addition of a cosmetic capping pass which resulted in greater grain refinement. This suggests that repair procedures utilizing a stringer or temper bead technique may reduce the effect of weld repairs on toughness.

  5. Significance of changes in residual stresses and mechanical properties due to SMAW repair of girth welds in linepipe. Final report

    SciTech Connect

    McGaughy, T.; Boyles, L.

    1990-10-31

    This program assessed the effects of SMAW repair welding on changes in surface residual stress distribution, fracture toughness and hardness around girth weld joints in linepipe. The following types of repair welds were studied: a part wall repair, a multiple part wall repair and full wall repair. The results were compared with a non-repaired weld sample. It was found that for the weld samples studied in this program, the full wall repair produced the most severe residual stress distribution followed by the multiple and single part wall repairs. The single repair only slightly increased the residual stress distribution when compared to the as-welded condition. Dramatic reductions in toughness were found in the multiple and full repairs due to coarse-grained regions produced during the repair operations. The single part wall repair exhibited an increase in toughness as a result of the addition of a cosmetic capping pass which resulted in greater grain refinement. This suggests that repair procedures utilizing a stringer or temper bead technique may reduce the effect of weld repairs on toughness.

  6. Immunoengineering nerve repair

    PubMed Central

    Mokarram, Nassir; Dymanus, Kyle; Srinivasan, Akhil; Tipton, John; Chu, Jason; English, Arthur W.; Bellamkonda, Ravi V.

    2017-01-01

    Injuries to the peripheral nervous system are major sources of disability and often result in painful neuropathies or the impairment of muscle movement and/or normal sensations. For gaps smaller than 10 mm in rodents, nearly normal functional recovery can be achieved; for longer gaps, however, there are challenges that have remained insurmountable. The current clinical gold standard used to bridge long, nonhealing nerve gaps, the autologous nerve graft (autograft), has several drawbacks. Despite best efforts, engineering an alternative “nerve bridge” for peripheral nerve repair remains elusive; hence, there is a compelling need to design new approaches that match or exceed the performance of autografts across critically sized nerve gaps. Here an immunomodulatory approach to stimulating nerve repair in a nerve-guidance scaffold was used to explore the regenerative effect of reparative monocyte recruitment. Early modulation of the immune environment at the injury site via fractalkine delivery resulted in a dramatic increase in regeneration as evident from histological and electrophysiological analyses. This study suggests that biasing the infiltrating inflammatory/immune cellular milieu after injury toward a proregenerative population creates a permissive environment for repair. This approach is a shift from the current modes of clinical and laboratory methods for nerve repair, which potentially opens an alternative paradigm to stimulate endogenous peripheral nerve repair. PMID:28611218

  7. 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

  8. Dynamics of DNA Mismatch Repair

    NASA Astrophysics Data System (ADS)

    Coats, Julie; Lin, Yuyen; Rasnik, Ivan

    2009-11-01

    DNA mismatch repair protects the genome from spontaneous mutations by recognizing errors, excising damage, and re-synthesizing DNA in a pathway that is highly conserved. Mismatch recognition is accomplished by the MutS family of proteins which are weak ATPases that bind specifically to damaged DNA, but the specific molecular mechanisms by which these proteins recognize damage and initiate excision are not known. Previous structural investigations have implied that protein-induced conformational changes are central to mismatch recognition. Because damage detection is a highly dynamic process in which conformational changes of the protein-DNA complexes occur on a time scale of a few seconds, it is difficult to obtain meaningful kinetic information with traditional ensemble techniques. In this work, we use single molecule fluorescence resonance energy transfer (smFRET) to study the conformational dynamics of fluorescently labeled DNA substrates in the presence of the mismatch repair protein MutS from E. coli and its human homolog MSH2/MSH6. Our studies allow us to obtain quantitative kinetic information about the rates of binding and dissociation and to determine the conformational states for each protein-DNA complex.

  9. Requirements of nano-machining repair system for 45-nm node

    NASA Astrophysics Data System (ADS)

    Lee, Sang-Hyeon; Kim, Hwa-Sung; Shim, Hong-Seok; Lee, Su-Young; Kim, Geun-Bae; Kwon, Hyuk-Joo; Woo, Sang-Gyun; Cho, Han-Ku

    2007-05-01

    Nano-machining repair tool plays an important role in the current 65 nm node photomask repair. It removes defects mechanically with nanometer sized diamond tip with high accuracy and low damage using high accuracy AFM data. The repair performance of nano-machining repair system largely depends on the diamond tip whose aspect ratio decides the minimum reparable feature size. As the device shrinks to 45 nm or 32 nm node, higher aspect ratio tip with weak structure is required. It is contradiction to the fact that more accurate edge placement and better repair slope is required in smaller node repair, because deflection or tip wear effect could happen in high aspect ratio tip. In this article, deflection and wear effect were investigated in single layer repair recipe using SEM and AIMS TM. Multilayer recipe which complements weak structure was estimated carefully, and some limits were discussed. Finally some requirements of nano-machining repair system for 45 nm node were presented.

  10. Base Excision Repair

    PubMed Central

    Krokan, Hans E.; Bjørås, Magnar

    2013-01-01

    Base excision repair (BER) corrects DNA damage from oxidation, deamination and alkylation. Such base lesions cause little distortion to the DNA helix structure. BER is initiated by a DNA glycosylase that recognizes and removes the damaged base, leaving an abasic site that is further processed by short-patch repair or long-patch repair that largely uses different proteins to complete BER. At least 11 distinct mammalian DNA glycosylases are known, each recognizing a few related lesions, frequently with some overlap in specificities. Impressively, the damaged bases are rapidly identified in a vast excess of normal bases, without a supply of energy. BER protects against cancer, aging, and neurodegeneration and takes place both in nuclei and mitochondria. More recently, an important role of uracil-DNA glycosylase UNG2 in adaptive immunity was revealed. Furthermore, other DNA glycosylases may have important roles in epigenetics, thus expanding the repertoire of BER proteins. PMID:23545420

  11. Incisional hernia repair.

    PubMed

    Millikan, Keith W

    2003-10-01

    Incisional ventral hernias are a common problem encountered by surgeons, with over 100,000 repairs being performed annually in the United States. Although many predisposing factors for incisional ventral hernia are patient-related, some factors such as type of primary closure and materials used may reduce the overall incidence of incisional ventral hernia. With the advent of prosthetic meshes being used for incisional ventral hernia repair, the recurrence rate has dropped to approximately 10%. More recently, with the development of prosthetic mesh that is now safe to place intraperitoneally, the recurrence rate has dropped to under 5%. The current controversies that exist for incisional ventral hernia repair are which approach to use (open versus laparoscopic) and what type of fixation (partial- versus full-thickness abdominal muscular/fascial wall) is necessary to stabilize the position of the mesh while tissue ingrowth occurs. During the next decade the answers to these controversies should be available in the surgical literature.

  12. 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.

  13. 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, and produce modified schedules quickly. 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. These experiments were performed within the domain of Space Shuttle ground processing.

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

    PubMed

    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.

  15. Joking Repair and the Organization of Repair in Conversation.

    ERIC Educational Resources Information Center

    Norrick, Neal R.

    This analysis looks at the humorous use of second-speaker repeats to initiate conversational repair. It is proposed that consideration of joking repeats forces reanalysis of the organization of conversational repair. The preference analysis theory is rejected in favor of a locally governed analysis of conversational repair in which participants…

  16. Imperforate anus repair - series (image)

    MedlinePlus

    ... for passage of stool. Complete absence of an anal opening requires emergency surgery for the newborn. Surgical ... for several months before attempting the more complex anal repair. The anal repair involves an abdominal incision, ...

  17. Abdominal aortic aneurysm repair - open

    MedlinePlus

    AAA - open; Repair - aortic aneurysm - open ... Open surgery to repair an AAA is sometimes done as an emergency procedure when there is bleeding inside your body from the aneurysm. You may have an ...

  18. About the Collision Repair Campaign

    EPA Pesticide Factsheets

    EPA developed the Collision Repair Campaign to focus on meaningful risk reduction in the Collision Repair source sector to complement ongoing community air toxics work and attain reductions at a faster rate.

  19. 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.

  20. 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

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

    PubMed

    Zhu, Songli; Peng, Aimin

    2016-06-21

    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.

  2. Immediate weight bearing after modified percutaneous Achilles tendon repair.

    PubMed

    Patel, Vishal C; Chandrakant, Vishal; Lozano-Calderon, Santiago; McWilliam, James

    2012-12-01

    Controversy exists regarding postoperative treatment of Achilles tendon repair. The purpose of this study was to evaluate the results of immediate weight bearing following modified percutaneous Achilles tendon repair using readily available materials. Fifty-two patients who were treated at a single center from 2000 to 2009 underwent percutaneous Achilles tendon repair by a single surgeon and were allowed immediate weight bearing. They were followed for on average of 2 years postoperatively and evaluated with functional and subjective outcomes. The average American Orthopaedic Foot and Ankle Society ankle-hindfoot scale was 96 points (range, 81 to 100), with 95% confidence interval ranging from 89.1 to 102.9. Subjective evaluation demonstrated that 47 patients (90%) were able to return to a desired level of activity, with an overall complication rate of 11.5%. Immediate weight bearing after percutaneous Achilles tendon repair had a low overall complication rate with good clinical and functional outcomes.

  3. Double row repair: is it worth the hassle?

    PubMed

    Papalia, Rocco; Franceschi, Francesco; Del Buono, Angelo; Zampogna, Biagio; Maffulli, Nicola; Denaro, Vincenzo

    2011-12-01

    In the operative management of rotator cuff disease, comparable functional results have been reported after open or mini-open repair and arthroscopic fixation. Surgical repair aims to re-establish an anatomical configuration of the tendon-bone construct for restoring its mechanical performance. Single row repair is the most commonly used technique, but recently some authors have proposed to re-establish the rotator cuff footprint with 2 rows of suture anchors ("double row" repair). In regard to imaging assessment, at time zero double row repair results being more anatomic and allows for structurally sound restoration of the rotator cuff footprint. However, this does not seem to translate into superior clinical outcomes for the double row repair when evaluating all different sizes of rotator cuff tears as a whole. The scientific basis for recommending single or double row repair as preferred treatment for patients with rotator cuff tear is questionable, as minimal differences have been measured on clinical and functional rating scales.

  4. Monolith Joint Repairs: Case Histories

    DTIC Science & Technology

    1989-08-01

    REPAIR, EVALUATION, MAINTENANCE, AND REHABILITATION RESEARCH PROGRAM TECHNICAL REPORT REMR-CS-22 MONOLITH JOINT REPAIRS: CASE HISTORVS.Z by James G ...Washington, DC 20314-1000 32307 S11. TITLE (Include Security Classification) Monolith Joint Repairs: Case Histories 12. PERSONAL AUTHOR(S) May. James G ...Research Work Unit 32307, "Tech- niques for Joint Repair and Rehabilitation," for which MAJ James G . May, CE, is the Principal Investigator. This work unit

  5. 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.

  6. 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…

  7. Intestinal obstruction repair - slideshow

    MedlinePlus

    ... this page: //medlineplus.gov/ency/presentations/100116.htm Intestinal obstruction repair - series—Normal anatomy To use the sharing ... M. Editorial team. Related MedlinePlus Health Topics Adhesions Intestinal Obstruction A.D.A.M., Inc. is accredited by ...

  8. 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…

  9. 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,…

  10. Krikalev during Elektron repair

    NASA Image and Video Library

    2005-05-05

    ISS011-E-05509 (5 May 2005) --- Cosmonaut Sergei K. Krikalev, Expedition 11 commander representing Russia's Federal Space Agency, uses a power tool as he makes repairs to the Elektron oxygen generator in the Zvezda Service Module of the International Space Station (ISS).

  11. Krikalev during Elektron repair

    NASA Image and Video Library

    2005-05-05

    ISS011-E-05513 (5 May 2005) --- Cosmonaut Sergei K. Krikalev, Expedition 11 commander representing Russia's Federal Space Agency, poses beside the disconnected Liquid Unit #5 (BZh-5) and the O2 end-filter (BD, secondary purification unit) from the BZh5 he removed while making repairs to the Elektron oxygen generator in the Zvezda Service Module of the international space station.

  12. Krikalev during Elektron repair

    NASA Image and Video Library

    2005-05-05

    ISS011-E-05504 (5 May 2005) --- Cosmonaut Sergei K. Krikalev, Expedition 11 commander representing Russia's Federal Space Agency, uses a video camera to document repairs to the Elektron oxygen generator in the Zvezda Service Module of the International Space Station (ISS).

  13. Krikalev during Elektron repair

    NASA Image and Video Library

    2005-05-05

    ISS011-E-05510 (5 May 2005) --- Cosmonaut Sergei K. Krikalev, Expedition 11 commander representing Russia's Federal Space Agency, uses a power tool as he makes repairs to the Elektron oxygen generator in the Zvezda Service Module of the International Space Station (ISS).

  14. 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.

  15. Eardrum repair - slideshow

    MedlinePlus

    ... anatomy URL of this page: //medlineplus.gov/ency/presentations/100015.htm Eardrum repair - series—Normal anatomy To use the sharing features on this page, please enable JavaScript. Go to slide 1 out of 4 Go to slide 2 ...

  16. 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,…

  17. Auto Repair Gets Technical.

    ERIC Educational Resources Information Center

    Steiger, Jim; Shoemaker, Byrl

    1989-01-01

    Rapid advances in automotive technology and the growth of the automotive service industry have created opportunities in car repair, parts supply, and body work. Certification is the best way for vocational educators to ensure that their programs prepare students for work in the automotive industry. (JOW)

  18. Getting Ready To Repair.

    ERIC Educational Resources Information Center

    Stryker, Rick

    2002-01-01

    Successful camp repairs require careful planning. Prioritize projects by program needs first, then by cost. Determine the cause of deterioration and address it. Build goodwill with suppliers by knowing what you want and giving them ample time to prepare estimates. Include labor costs, even for staff labor. A cost-estimate table for a sample…

  19. 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,…

  20. 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.

  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. 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…

  3. A retrospective evaluation of the aesthetics of the nasolabial complex after unilateral cleft lip repair using the Tennison-Randall technique: a study of 44 cases treated in a single cleft center.

    PubMed

    Iliopoulos, Christos; Mitsimponas, Konstantinos; Lazaridou, Dimitra; Neukam, Friedrich Wilhelm; Stelzle, Florian

    2014-12-01

    Among numerous techniques that have been described for lip repair, the Tennison-Randall method has gained popularity over time and is preferred by many surgeons due to the predictability of the outcome. This study aims to evaluate the esthetic outcome reached in the nasolabial region following primary lip repair with the use of this method. Forty-four patients with unilateral cleft lip (with or without alveolar cleft) were assessed retrospectively through a photographic evaluation by two clinicians with regard to the aesthetics of the lip and nose separately as anatomical subunits as well as of the nasolabial region as an anatomical complex. The collected data were statistically analyzed with regard to the cleft subtype and the performance of corrective surgeries for the lip and/or the nose. The method was associated with good results, especially when it comes to the appearance of the nose as an anatomical subunit, as well as of the nasolabial region as a complex, regarding cleft lip patients without an alveolar cleft. The Tennison-Randall technique proved to be a very satisfying method in terms of the esthetic long-term outcome in our patient collective. Copyright © 2014 European Association for Cranio-Maxillo-Facial Surgery. Published by Elsevier Ltd. All rights reserved.

  4. Laparoscopic repair of femoral hernia

    PubMed Central

    Yang, Xue-Fei

    2016-01-01

    Laparoscopic repair of inguinal hernia is mini-invasive and has confirmed effects. Femoral hernia could be repaired through the laparoscopic procedures for inguinal hernia. These procedures have clear anatomic view in the operation and preoperatively undiagnosed femoral hernia could be confirmed and treated. Lower recurrence ratio was reported in laparoscopic procedures compared with open procedures for repair of femoral hernia. The technical details of laparoscopic repair of femoral hernia, especially the differences to laparoscopic repair of inguinal hernia are discussed in this article. PMID:27826574

  5. Repair of radiation-induced DNA damage in nondividing populations of human diploid fibroblasts

    SciTech Connect

    Kantor, G.J.; Petty, R.S.; Warner, C.; Phillips, D.J.H.; Hull, D.R.

    1980-06-01

    The occurrence of DNA repair in uv- (254 nm) and x-irradiated normal human diploid fibroblasts maintained in a quiescent, nondividing state using low serum (0.5%) medium was ascertained. Techniques that detect different steps of the excision repair process were used so that the extent of completion of repair at single sites could be determined. These included measuring the disappearance of pyrimidine dimers by chromatography, detecting repair synthesis by density-gradient and autoradiographic methods and detecting the rejoining of repaired regions and repair of x-ray-induced single-strand DNA breaks using alkaline sucrose gradients. Results show that dimer excision occurs and the subsequent steps of repair synthesis and ligation are completed. About 50% of the dimers formed by exposure to 20 J/m/sup 2/ is excised in the initial 24-h post-uv period. DNA repair (unscheduled DNA synthesis) can be detected through a 5-d post-uv period. The fraction of damaged sites eventually repaired is not known. X-ray-induced single-strand DNA breaks are repaired rapidly.

  6. Analysis of a knotless flexor tendon repair using a multifilament stainless steel cable-crimp system.

    PubMed

    Gordon, Leonard; Matsui, Jun; McDonald, Erik; Gordon, Joshua A; Neimkin, Ronald

    2013-04-01

    To compare the biomechanical and technical properties of flexor tendon repairs using a 4-strand cruciate FiberWire (FW) repair and a 2-strand multifilament stainless steel (MFSS) single cross-lock cable-crimp system. Eight tests were conducted for each type of repair using cadaver hand flexor digitorum profundus tendons. We measured the required surgical exposure, repair time, and force of flexion (friction) with a custom motor system with an inline load cell and measured ultimate tensile strength (UTS) and 2-mm gap force on a servo-hydraulic testing machine. Repair time averaged less than 7 minutes for the 2-strand MFSS cable crimp repairs and 12 minutes for the FW repairs. The FW repair was performed with 2 cm of exposure and removal of the C-1 and A-3 pulleys. The C-1 and A-3 pulleys were retained in each of the MFSS cable crimp repairs with less than 1 cm of exposure. Following the FW repair, the average increase in friction was 89% compared with an average of 53% for the MFSS repairs. Six of the 8 MFSS specimens achieved the UTS before any gap had occurred, whereas all of the FW repairs had more than 2 mm of gap before the UTS, indicating that the MFSS was a stiffer repair. The average UTS appeared similar for both groups. We describe a 2-strand multifilament stainless steel single cross-lock cable crimp flexor repair system. In our studies of this cable crimp system, we found that surgical exposure, average repair times, and friction were reduced compared to the traditional 4-strand cruciate FW repair. While demonstrating these benefits, the crimp repair also produced a stiff construct and high UTS and 2-mm gap force. A cable crimp flexor tendon repair may offer an attractive alternative to current repair methods. The benefits may be important especially for flexor tendon repair in zone 2 or for the repair of multiple tendons. Copyright © 2013 American Society for Surgery of the Hand. Published by Elsevier Inc. All rights reserved.

  7. Minimally Invasive Spigelian Hernia Repair

    PubMed Central

    Baucom, Catherine; Nguyen, Quan D.; Hidalgo, Marco

    2009-01-01

    Introduction: Spigelian hernia is an uncommon ventral hernia characterized by a defect in the linea semilunaris. Repair of spigelian hernia has traditionally been accomplished via an open transverse incision and primary repair. The purpose of this article is to present 2 case reports of incarcerated spigelian hernia that were successfully repaired laparoscopically using Gortex mesh and to present a review of the literature regarding laparoscopic repair of spigelian hernias. Methods: Retrospective chart review and Medline literature search. Results: Two patients underwent laparoscopic mesh repair of incarcerated spigelian hernias. Both were started on a regular diet on postoperative day 1 and discharged on postoperative days 2 and 3. One patient developed a seroma that resolved without intervention. There was complete resolution of preoperative symptoms at the 12-month follow-up. Conclusion: Minimally invasive repair of spigelian hernias is an alternative to the traditional open surgical technique. Further studies are needed to directly compare the open and the laparoscopic repair. PMID:19660230

  8. Damage tolerance of bonded composite aircraft repairs for metallic structures

    NASA Astrophysics Data System (ADS)

    Clark, Randal John

    This thesis describes the development and validation of methods for damage tolerance substantiation of bonded composite repairs applied to cracked plates. This technology is used to repair metal aircraft structures, offering improvements in fatigue life, cost, manufacturability, and inspectability when compared to riveted repairs. The work focuses on the effects of plate thickness and bending on repair life, and covers fundamental aspects of fracture and fatigue of cracked plates and bonded joints. This project falls under the UBC Bonded Composite Repair Program, which has the goal of certification and widespread use of bonded repairs in civilian air transportation. This thesis analyses the plate thickness and transverse stress effects on fracture of repaired plates and the related problem of induced geometrically nonlinear bending in unbalanced (single-sided) repairs. The author begins by developing a classification scheme for assigning repair damage tolerance substantiation requirements based upon stress-based adhesive fracture/fatigue criteria and the residual strength of the original structure. The governing equations for bending of cracked plates are then reformulated and line-spring models are developed for linear and nonlinear coupled bending and extension of reinforced cracks. The line-spring models were used to correct the Wang and Rose energy method for the determination of the long-crack limit stress intensity, and to develop a new interpolation model for repaired cracks of arbitrary length. The analysis was validated using finite element models and data from mechanical tests performed on hybrid bonded joints and repair specimens that are representative of an in-service repair. This work will allow designers to evaluate the damage tolerance of the repaired plate, the adhesive, and the composite patch, which is an airworthiness requirement under FAR (Federal Aviation Regulations) 25.571. The thesis concludes by assessing the remaining barriers to

  9. Laceration repair in children.

    PubMed

    Lawton, Benjamin; Hadj, Andrew

    2014-09-01

    Issues faced in the management of lacerations in children include control of pain and distress, wound cleaning and closure, referral decisions, awareness of potential associated injuries and strategies to prevent complications and optimise cosmetic outcome. The possibility of non-accidental injury may also require exploration. This update will attempt to offer a current, evidence-informed approach to management of the most commonly seen lacerations, and discuss when specialist referral is appropriate. Successful laceration repair in children is a procedure that blends the arts of anaesthesia, distraction and reassurance with the mechanics of tissue repair itself. Although each laceration and each child deserves an individualised approach, certain principles remain consistent and provide the backbone of a decision-making structure in this therapeutic area.

  10. Rapid Runway Repair Study.

    DTIC Science & Technology

    This report describes a series of tests to evaluate a system for rapidly repairing airfield pavement using polymer concrete (synthetic polymer plus...aggregate), thermally cured by microwave power. The technique, developed by the Syracuse University Research Corporation (SURC) for highway...maintenance, uses a truck-mounted 50-kilowatt microwave generator to irradiate areas patched with polymer concrete . Test results indicate that the polymer

  11. Repair of Auricular Defects.

    PubMed

    Watson, Deborah; Hecht, Avram

    2017-08-01

    Repairing defects of the auricle requires an appreciation of the underlying 3-dimensional framework, the flexible properties of the cartilages, and the healing contractile tendencies of the surrounding soft tissue. In the analysis of auricular defects and planning of their reconstruction, it is helpful to divide the auricle into subunits for which different techniques may offer better functional and aesthetic outcomes. This article reviews many of the reconstructive options for defects of the various auricular subunits. Published by Elsevier Inc.

  12. 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

  13. Canonical DNA Repair Pathways Influence R-Loop-Driven Genome Instability.

    PubMed

    Stirling, Peter C; Hieter, Philip

    2016-07-22

    DNA repair defects create cancer predisposition in humans by fostering a higher rate of mutations. While DNA repair is quite well characterized, recent studies have identified previously unrecognized relationships between DNA repair and R-loop-mediated genome instability. R-loops are three-stranded nucleic acid structures in which RNA binds to genomic DNA to displace a loop of single-stranded DNA. Mutations in homologous recombination, nucleotide excision repair, crosslink repair, and DNA damage checkpoints have all now been linked to formation and function of transcription-coupled R-loops. This perspective will summarize recent literature linking DNA repair to R-loop-mediated genomic instability and discuss how R-loops may contribute to mutagenesis in DNA-repair-deficient cancers.

  14. Single nucleotide polymorphisms (SNPs) of ERCC2, hOGG1, and XRCC1 DNA