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Sample records for dna lesions removed

  1. Accumulation of premutagenic DNA lesions in mice defective in removal of oxidative base damage

    Science.gov (United States)

    Klungland, Arne; Rosewell, Ian; Hollenbach, Stephan; Larsen, Elisabeth; Daly, Graham; Epe, Bernd; Seeberg, Erling; Lindahl, Tomas; Barnes, Deborah E.

    1999-01-01

    DNA damage generated by oxidant byproducts of cellular metabolism has been proposed as a key factor in cancer and aging. Oxygen free radicals cause predominantly base damage in DNA, and the most frequent mutagenic base lesion is 7,8-dihydro-8-oxoguanine (8-oxoG). This altered base can pair with A as well as C residues, leading to a greatly increased frequency of spontaneous G·C→T·A transversion mutations in repair-deficient bacterial and yeast cells. Eukaryotic cells use a specific DNA glycosylase, the product of the OGG1 gene, to excise 8-oxoG from DNA. To assess the role of the mammalian enzyme in repair of DNA damage and prevention of carcinogenesis, we have generated homozygous ogg1−/− null mice. These animals are viable but accumulate abnormal levels of 8-oxoG in their genomes. Despite this increase in potentially miscoding DNA lesions, OGG1-deficient mice exhibit only a moderately, but significantly, elevated spontaneous mutation rate in nonproliferative tissues, do not develop malignancies, and show no marked pathological changes. Extracts of ogg1 null mouse tissues cannot excise the damaged base, but there is significant slow removal in vivo from proliferating cells. These findings suggest that in the absence of the DNA glycosylase, and in apparent contrast to bacterial and yeast cells, an alternative repair pathway functions to minimize the effects of an increased load of 8-oxoG in the genome and maintain a low endogenous mutation frequency. PMID:10557315

  2. Skin lesion removal

    Science.gov (United States)

    ... likely to be done when there is a concern about a skin cancer. Most often, an area the shape of an ellipse is removed, as this makes it easier to close with stitches. The entire lesion is removed, going as deep as the fat, if needed, to ...

  3. Immunological probes for lesions and repoair patches in DNA

    International Nuclear Information System (INIS)

    Leadon, S.A.

    1988-01-01

    This paper describes two immunological approaches for the detection of DNA damage and its repair. The first uses a monoclonal antibody to directly measure the production and removal of one type of oxidized base, thymine glycol; the second uses an antibody to detect the repair synthesis event itself and, when combined with the use of molecular biological techniques, can be used to monitor the production and removal of lesions in specific sequences within the genome

  4. Managing Carious Lesions: Consensus Recommendations on Carious Tissue Removal

    NARCIS (Netherlands)

    Schwendicke, F.; Frencken, J.E.; Bjorndal, L.; Maltz, M.; Manton, D.J.; Ricketts, D.; Van Landuyt, K.; Banerjee, A.; Campus, G.; Domejean, S.; Fontana, M.; Leal, S.; Lo, E.; Machiulskiene, V.; Schulte, A.; Splieth, C.; Zandona, A.F.; Innes, N.P.

    2016-01-01

    The International Caries Consensus Collaboration undertook a consensus process and here presents clinical recommendations for carious tissue removal and managing cavitated carious lesions, including restoration, based on texture of demineralized dentine. Dentists should manage the disease dental

  5. Managing Carious Lesions: Consensus Recommendations on Carious Tissue Removal.

    Science.gov (United States)

    Schwendicke, F; Frencken, J E; Bjørndal, L; Maltz, M; Manton, D J; Ricketts, D; Van Landuyt, K; Banerjee, A; Campus, G; Doméjean, S; Fontana, M; Leal, S; Lo, E; Machiulskiene, V; Schulte, A; Splieth, C; Zandona, A F; Innes, N P T

    2016-05-01

    The International Caries Consensus Collaboration undertook a consensus process and here presents clinical recommendations for carious tissue removal and managing cavitated carious lesions, including restoration, based on texture of demineralized dentine. Dentists should manage the disease dental caries and control activity of existing cavitated lesions to preserve hard tissues and retain teeth long-term. Entering the restorative cycle should be avoided as far as possible. Controlling the disease in cavitated carious lesions should be attempted using methods which are aimed at biofilm removal or control first. Only when cavitated carious lesions either are noncleansable or can no longer be sealed are restorative interventions indicated. When a restoration is indicated, the priorities are as follows: preserving healthy and remineralizable tissue, achieving a restorative seal, maintaining pulpal health, and maximizing restoration success. Carious tissue is removed purely to create conditions for long-lasting restorations. Bacterially contaminated or demineralized tissues close to the pulp do not need to be removed. In deeper lesions in teeth with sensible (vital) pulps, preserving pulpal health should be prioritized, while in shallow or moderately deep lesions, restoration longevity becomes more important. For teeth with shallow or moderately deep cavitated lesions, carious tissue removal is performed according toselective removal to firm dentine.In deep cavitated lesions in primary or permanent teeth,selective removal to soft dentineshould be performed, although in permanent teeth,stepwise removalis an option. The evidence and, therefore, these recommendations support less invasive carious lesion management, delaying entry to, and slowing down, the restorative cycle by preserving tooth tissue and retaining teeth long-term. © International & American Associations for Dental Research 2016.

  6. Clustered DNA lesion repair in eukaryotes: Relevance to mutagenesis and cell survival

    Energy Technology Data Exchange (ETDEWEB)

    Sage, Evelyne [Institut Curie, Bat. 110, Centre Universitaire, 91405 Orsay (France); CNRS UMR3348, Bat. 110, Centre Universitaire, 91405 Orsay (France); Harrison, Lynn, E-mail: lclary@lsuhsc.edu [Department of Molecular and Cellular Physiology, LSUHSC-S, 1501 Kings Highway, Shreveport, LA 71130 (United States)

    2011-06-03

    A clustered DNA lesion, also known as a multiply damaged site, is defined as {>=}2 damages in the DNA within 1-2 helical turns. Only ionizing radiation and certain chemicals introduce DNA damage in the genome in this non-random way. What is now clear is that the lethality of a damaging agent is not just related to the types of DNA lesions introduced, but also to how the damage is distributed in the DNA. Clustered DNA lesions were first hypothesized to exist in the 1990s, and work has progressed where these complex lesions have been characterized and measured in irradiated as well as in non-irradiated cells. A clustered lesion can consist of single as well as double strand breaks, base damage and abasic sites, and the damages can be situated on the same strand or opposing strands. They include tandem lesions, double strand break (DSB) clusters and non-DSB clusters, and base excision repair as well as the DSB repair pathways can be required to remove these complex lesions. Due to the plethora of oxidative damage induced by ionizing radiation, and the repair proteins involved in their removal from the DNA, it has been necessary to study how repair systems handle these lesions using synthetic DNA damage. This review focuses on the repair process and mutagenic consequences of clustered lesions in yeast and mammalian cells. By examining the studies on synthetic clustered lesions, and the effects of low vs high LET radiation on mammalian cells or tissues, it is possible to extrapolate the potential biological relevance of these clustered lesions to the killing of tumor cells by radiotherapy and chemotherapy, and to the risk of cancer in non-tumor cells, and this will be discussed.

  7. From DNA lesions to tissue malfunction

    International Nuclear Information System (INIS)

    Denekamp, J.

    1989-01-01

    After large doses of radiation, tissues fail to function when the proliferating cells lose their clonogenic ability. This results from unrepaired or misrepaired double strand breaks in the DNA. The lesions are inflicted immediately but there is a variable latent period before tissue damage is expressed. This ranges from a few days in intestine, to weeks in skin, and to months or years in deep visceral tissues, e.g. heart, lung, kidney, spinal cord. The latency relates to the proliferation kinetics of each tissue component. Doses of 10-30 Gy do not cause serious functional defects in differentiated cells, but they prevent successful mitosis in proliferating cells. Thus each tissue continues to function until its differentiated cells are lost by normal wear and tear processes. After a time which relates to the natural lifespan of the differentiated cells, failure to provide replacement cells from the proliferating compartment becomes important and the tissue shows atrophy and eventually a functional deficit. If the radiation exposure is divided into a series of smaller exposures or is given at a low dose-rate, the biochemical repair of DNA is more effective and less damage is observed. After high LET ionizing radiation, e.g. neutrons or α particles, the response is almost linear and is not affected by doserate or fractionation. (author)

  8. Removable denture-related oral mucosal lesions: descriptive clinical study

    Directory of Open Access Journals (Sweden)

    Gökçen Akçiçek

    2017-05-01

    Full Text Available Objective: The aim of this study was to investigate whether there was a relationship between removable denture-related oral mucosal lesions and denture type, and demographic characteristics. Materials and Method: The age, sex, denture type, systemic condition and medication use, presence of denture-related oral mucosal lesions (DROML, their locations and patients’ awareness of above mentioned lesions were recorded for 199 patients. Pearson chi-square test was used to analyse the relationship between the DROML and denture type, and demographic characteristics of the patients. Results: Among the patients included to the study, 122 (61.3% were female and 77 (38.7% were male. Ninety-six patients (48.2% exhibited DROML, whereas 103 patients (51.8% had no DROML. No relationship was detected between DROML and age, and sex (p>0.05. The most commonly detected DROML was denture stomatitis (34.7%. Denture stomatitis was significantly more frequently seen in partial denture wearers (p<0.05, while epulis fissuratum and flabby ridge were statistically more frequent in complete denture wearers (p<0.001. Traumatic ulcer was more frequently found in mandibular complete denture wearers (p<0.05, while epulis fissuratum and flabby ridge were significantly more common in maxillary complete denture wearers (p<0.001. Among the patients with DROML, 57.3% stated that they were unaware of these lesions. Conclusion: In this study sample, the rate of DROML was high in patients wearing removable dentures (48.2%, and more than half of the patients with DROML were not aware of these lesions. Upon these findings, it is considered that removable denture wearers should follow the denture usage instructions and should be informed about the importance of periodic controls.

  9. Spontaneous mutation by mutagenic repair of spontaneous lesions in DNA

    International Nuclear Information System (INIS)

    Hastings, P.J.; Quah, S.-K.; Borstel, R.C. von

    1976-01-01

    It is stated that strains of yeast carrying mutations in many of the steps in pathways repairing radiation-induced damage to DNA have enhanced spontaneous mutation rates. Most strains isolated because they have enhanced spontaneous mutation carry mutations in DNA repair systems. This suggests that much spontaneous mutation arises by mutagenic repair of spontaneous lesions. (author)

  10. Archaeal RNA polymerase arrests transcription at DNA lesions.

    Science.gov (United States)

    Gehring, Alexandra M; Santangelo, Thomas J

    2017-01-01

    Transcription elongation is not uniform and transcription is often hindered by protein-bound factors or DNA lesions that limit translocation and impair catalysis. Despite the high degree of sequence and structural homology of the multi-subunit RNA polymerases (RNAP), substantial differences in response to DNA lesions have been reported. Archaea encode only a single RNAP with striking structural conservation with eukaryotic RNAP II (Pol II). Here, we demonstrate that the archaeal RNAP from Thermococcus kodakarensis is sensitive to a variety of DNA lesions that pause and arrest RNAP at or adjacent to the site of DNA damage. DNA damage only halts elongation when present in the template strand, and the damage often results in RNAP arresting such that the lesion would be encapsulated with the transcription elongation complex. The strand-specific halt to archaeal transcription elongation on modified templates is supportive of RNAP recognizing DNA damage and potentially initiating DNA repair through a process akin to the well-described transcription-coupled DNA repair (TCR) pathways in Bacteria and Eukarya.

  11. MRI and pathological findings of epileptogenic lesions removed surgically

    International Nuclear Information System (INIS)

    Moritake, Kouzo; Kikuchi, Haruhiko; Minamikawa, Jun

    1990-01-01

    MRI revealed focal cerebral lesions in 19 patients, 12 males and 7 females, who had suffered from disabling seizures refractory to medical therapy for over one year; the lengths of the periods of therapy ranged from one to 17 years; mean: 8.8 years. Their ages at surgery ranged from 3 to 46 years; mean: 15.2 years. The results of other preoperative and intraoperative examinations, including mobile long-term ambulatory EEG monitoring, local CBF two-dimensional imaging by SPECT, and intraoperative cortical EEG, justified the surgical resection of those lesions revealed by MRI. These lesions were removed totally or subtotally. The pathological findings of the excised lesions were neuronal loss and gliosis in 10 cases (porencephaly, 2; arachnoid cyst, 3; post-traumatic scar, 1; nonspecific infarct, 4), hamartomatous pathology in 5 (hemartoma, 1; tuberous sclerosis, 4), and neoplasm in 4 (low-grade astrocytoma, 2; oligodendroglioma, 1; epidermoid, 1). The common pathological feature of these lesions was the proliferation of abnormal glial cells, which are sensitive to MRI imaging, especially to T 2 -weighted images. The postoperative follow-up terms of these 19 patients ranged from 6 to 23 months; mean: 15 months. Epileptic attacks had ceased in 12 of the 19 patients (63%), and there had been a marked improvement in both the frequency and severity of attacks in another 4. No permanent surgical complications or worsening of the seizures were seen in any patient. In conclusion, MRI is sensitive to epileptogenic lesions in patients with medically intractable epilepsy and is helpful in defining their configurations and margins and in planning the surgical approach. (author)

  12. DNA Adducts aand Human Atherosclerotis Lesions

    Czech Academy of Sciences Publication Activity Database

    Strejc, Přemysl; Boubelík, O.; Stávková, Zdena; Chvátalová, Irena; Šrám, Radim

    2001-01-01

    Roč. 42, - (2001), s. 662 ISSN 0008-5472. [Annual Meeting of Proceedings /92./. 24.03.2001-28.03.2001, New Orleans] R&D Projects: GA MZd NM10 Keywords : DNA adducts * LDL cholesterol Subject RIV: DN - Health Impact of the Environment Quality

  13. Lesion removal and lesion addition algorithms in lung volumetric data sets for perception studies

    Science.gov (United States)

    Madsen, Mark T.; Berbaum, Kevin S.; Ellingson, Andrew; Thompson, Brad H.; Mullan, Brian F.

    2006-03-01

    Image perception studies of medical images provide important information about how radiologists interpret images and insights for reducing reading errors. In the past, perception studies have been difficult to perform using clinical imaging studies because of the problems associated with obtaining images demonstrating proven abnormalities and appropriate normal control images. We developed and evaluated interactive software that allows the seamless removal of abnormal areas from CT lung image sets. We have also developed interactive software for capturing lung lesions in a database where they can be added to lung CT studies. The efficacy of the software to remove abnormal areas of lung CT studies was evaluated psychophysically by having radiologists select the one altered image from a display of four. The software for adding lesions was evaluated by having radiologists classify displayed CT slices with lesions as real or artificial scaled to 3 levels of confidence. The results of these experiments demonstrated that the radiologist had difficulty in distinguishing the raw clinical images from those that had been altered. We conclude that this software can be used to create experimental normal control and "proven" lesion data sets for volumetric CT of the lung fields. We also note that this software can be easily adapted to work with other tissue besides lung and that it can be adapted to other digital imaging modalities.

  14. Modification of radiation-induced DNA lesions by oxygen

    International Nuclear Information System (INIS)

    Meyn, R.E.; Jenkins, W.T.

    1984-01-01

    The efficiency of DNA strand break production by radiation under aerated and hypoxic conditions was determined in CHO cells using the technique of alkaline elution. The resulting oxygen enhancement ratio was surprisingly high, 7.8. When the pH of the elution was increased from 12.1, the normally used pH, to 12.8, a substantial increase in the strand breaks produced in the hypoxic cells was observed, resulting in an OER of 4.8. This difference in susceptibility of DNA strand break detection as a function of pH suggested a difference in the type of lesions produced in DNA when irradiated under aerated and hypoxic conditions. Further experiments to examine the DNA-protein crosslinks produced by radiation suggested that the apparent lower level of strand breaks in hypoxic cells may be due to a higher level of DNA-protein crosslinks produced under hypoxic conditions. Thus, oxygen may not only act by modifying the quantity of radiation-induced DNA lesions but may also cause qualitative changes. If the different types of DNA lesions have different contributions to lethality, the OER for cell survival may represent a complex composite of these changes at the molecular level

  15. UVA photoactivation of DNA containing halogenated thiopyrimidines induces cytotoxic DNA lesions

    Science.gov (United States)

    Brem, Reto; Zhang, Xiaohui; Xu, Yao-Zhong; Karran, Peter

    2015-01-01

    Photochemotherapy, the combination of a photosensitiser and ultraviolet (UV) or visible light, is an effective treatment for skin conditions including cancer. The high mutagenicity and non-selectivity of photochemotherapy regimes warrants the development of alternative approaches. We demonstrate that the thiopyrimidine nucleosides 5-bromo-4-thiodeoxyuridine (SBrdU) and 5-iodo-4-thiodeoxyuridine (SIdU) are incorporated into the DNA of cultured human and mouse cells where they synergistically sensitise killing by low doses of UVA radiation. The DNA halothiopyrimidine/UVA combinations induce DNA interstrand crosslinks, DNA-protein crosslinks, DNA strand breaks, nucleobase damage and lesions that resemble UV-induced pyrimidine(6-4)pyrimidone photoproducts. These are potentially lethal DNA lesions and cells defective in their repair are hypersensitive to killing by SBrdU/UVA and SIdU/UVA. DNA SIdU and SBrdU generate lethal DNA photodamage by partially distinct mechanisms that reflect the different photolabilities of their C–I and C–Br bonds. Although singlet oxygen is involved in photolesion formation, DNA SBrdU and SIdU photoactivation does not detectably increase DNA 8-oxoguanine levels. The absence of significant collateral damage to normal guanine suggests that UVA activation of DNA SIdU or SBrdU might offer a strategy to target hyperproliferative skin conditions that avoids the extensive formation of a known mutagenic DNA lesion. PMID:25747491

  16. Theoretical approach of complex DNA lesions: from formation to repair

    International Nuclear Information System (INIS)

    Bignon, Emmanuelle

    2017-01-01

    This thesis work is focused on the theoretical modelling of DNA damages, from formation to repair. Several projects have been led in this framework, which can be sorted into three different parts. One on hand, we studied complex DNA reactivity. It included a study about 8-oxo-7,8-dihydro-guanine (8oxoG) mechanisms of formation, a project concerning the UV-induced pyrimidine 6-4 pyrimidone (6-4PP) endogenous photo-sensitizer features, and another one about DNA photo-sensitization by nonsteroidal anti-inflammatory drugs (i.e. ketoprofen and ibuprofen). On the other hand, we investigated mechanical properties of damaged DNA. The structural signature of a DNA lesion is of major importance for their repair, unfortunately only few NMR and X-ray structures of such systems are available. In order to gain insights into their dynamical structure, we investigated a series of complex damages: clustered abasic sites, interstrand cross-links, and the 6-4PP photo-lesion. Likewise, we studied the interaction modes DNA with several polyamines, which are well known to interact with the double helix, but also with the perspective to model DNA-protein cross-linking. The third part concerned the study of DNA interactions with repair enzymes. In line with the structural study about clustered abasic sites, we investigated the dynamics of the same system, but this time interacting with the APE1 endonuclease. We also studied interactions between the Fpg glycosylase with an oligonucleotides containing tandem 8-oxoG on one hand and 8-oxoG - abasic site as multiply damaged sites. Thus, we shed new lights on damaged DNA reactivity, structure and repair, which provides perspectives for biomedicine and life's mechanisms understanding as we begin to describe nucleosomal DNA. (author)

  17. Increased sensitivity of DNA damage response-deficient cells to stimulated microgravity-induced DNA lesions.

    Directory of Open Access Journals (Sweden)

    Nan Li

    Full Text Available Microgravity is a major stress factor that astronauts have to face in space. In the past, the effects of microgravity on genomic DNA damage were studied, and it seems that the effect on genomic DNA depends on cell types and the length of exposure time to microgravity or simulated microgravity (SMG. In this study we used mouse embryonic stem (MES and mouse embryonic fibroblast (MEF cells to assess the effects of SMG on DNA lesions. To acquire the insight into potential mechanisms by which cells resist and/or adapt to SMG, we also included Rad9-deleted MES and Mdc1-deleted MEF cells in addition to wild type cells in this study. We observed significant SMG-induced DNA double strand breaks (DSBs in Rad9-/- MES and Mdc1-/- MEF cells but not in their corresponding wild type cells. A similar pattern of DNA single strand break or modifications was also observed in Rad9-/- MES. As the exposure to SMG was prolonged, Rad9-/- MES cells adapted to the SMG disturbance by reducing the induced DNA lesions. The induced DNA lesions in Rad9-/- MES were due to SMG-induced reactive oxygen species (ROS. Interestingly, Mdc1-/- MEF cells were only partially adapted to the SMG disturbance. That is, the induced DNA lesions were reduced over time, but did not return to the control level while ROS returned to a control level. In addition, ROS was only partially responsible for the induced DNA lesions in Mdc1-/- MEF cells. Taken together, these data suggest that SMG is a weak genomic DNA stress and can aggravate genomic instability in cells with DNA damage response (DDR defects.

  18. Recombinational DNA repair is regulated by compartmentalization of DNA lesions at the nuclear pore complex

    DEFF Research Database (Denmark)

    Géli, Vincent; Lisby, Michael

    2015-01-01

    and colleagues shows that also physiological threats to genome integrity such as DNA secondary structure-forming triplet repeat sequences relocalize to the NPC during DNA replication. Mutants that fail to reposition the triplet repeat locus to the NPC cause repeat instability. Here, we review the types of DNA...... lesions that relocalize to the NPC, the putative mechanisms of relocalization, and the types of recombinational repair that are stimulated by the NPC, and present a model for NPC-facilitated repair....

  19. Correlation of bistranded clustered abasic DNA lesion processing with structural and dynamic DNA helix distortion

    Science.gov (United States)

    Bignon, Emmanuelle; Gattuso, Hugo; Morell, Christophe; Dehez, François; Georgakilas, Alexandros G.; Monari, Antonio; Dumont, Elise

    2016-01-01

    Clustered apurinic/apyrimidinic (AP; abasic) DNA lesions produced by ionizing radiation are by far more cytotoxic than isolated AP lesion entities. The structure and dynamics of a series of seven 23-bp oligonucleotides featuring simple bistranded clustered damage sites, comprising of two AP sites, zero, one, three or five bases 3′ or 5′ apart from each other, were investigated through 400 ns explicit solvent molecular dynamics simulations. They provide representative structures of synthetically engineered multiply damage sites-containing oligonucleotides whose repair was investigated experimentally (Nucl. Acids Res. 2004, 32:5609-5620; Nucl. Acids Res. 2002, 30: 2800–2808). The inspection of extrahelical positioning of the AP sites, bulge and non Watson–Crick hydrogen bonding corroborates the experimental measurements of repair efficiencies by bacterial or human AP endonucleases Nfo and APE1, respectively. This study provides unprecedented knowledge into the structure and dynamics of clustered abasic DNA lesions, notably rationalizing the non-symmetry with respect to 3′ to 5′ position. In addition, it provides strong mechanistic insights and basis for future studies on the effects of clustered DNA damage on the recognition and processing of these lesions by bacterial or human DNA repair enzymes specialized in the processing of such lesions. PMID:27587587

  20. Inducible DNA-repair systems in yeast: competition for lesions.

    Science.gov (United States)

    Mitchel, R E; Morrison, D P

    1987-03-01

    DNA lesions may be recognized and repaired by more than one DNA-repair process. If two repair systems with different error frequencies have overlapping lesion specificity and one or both is inducible, the resulting variable competition for the lesions can change the biological consequences of these lesions. This concept was demonstrated by observing mutation in yeast cells (Saccharomyces cerevisiae) exposed to combinations of mutagens under conditions which influenced the induction of error-free recombinational repair or error-prone repair. Total mutation frequency was reduced in a manner proportional to the dose of 60Co-gamma- or 254 nm UV radiation delivered prior to or subsequent to an MNNG exposure. Suppression was greater per unit radiation dose in cells gamma-irradiated in O2 as compared to N2. A rad3 (excision-repair) mutant gave results similar to wild-type but mutation in a rad52 (rec-) mutant exposed to MNNG was not suppressed by radiation. Protein-synthesis inhibition with heat shock or cycloheximide indicated that it was the mutation due to MNNG and not that due to radiation which had changed. These results indicate that MNNG lesions are recognized by both the recombinational repair system and the inducible error-prone system, but that gamma-radiation induction of error-free recombinational repair resulted in increased competition for the lesions, thereby reducing mutation. Similarly, gamma-radiation exposure resulted in a radiation dose-dependent reduction in mutation due to MNU, EMS, ENU and 8-MOP + UVA, but no reduction in mutation due to MMS. These results suggest that the number of mutational MMS lesions recognizable by the recombinational repair system must be very small relative to those produced by the other agents. MNNG induction of the inducible error-prone systems however, did not alter mutation frequencies due to ENU or MMS exposure but, in contrast to radiation, increased the mutagenic effectiveness of EMS. These experiments demonstrate

  1. DNA repair is responsible for the presence of oxidatively damaged DNA lesions in urine

    International Nuclear Information System (INIS)

    Cooke, Marcus S.; Evans, Mark D.; Dove, Rosamund; Rozalski, Rafal; Gackowski, Daniel; Siomek, Agnieszka; Lunec, Joseph; Olinski, Ryszard

    2005-01-01

    The repair of oxidatively damaged DNA is integral to the maintenance of genomic stability, and hence prevention of a wide variety of pathological conditions, such as aging, cancer and cardiovascular disease. The ability to non-invasively assess DNA repair may provide information regarding repair pathways, variability in repair capacity, and susceptibility to disease. The development of assays to measure urinary DNA lesions offered this potential, although it rapidly became clear that possible contribution from diet and cell turnover may influence urinary lesion levels. Whilst early studies attempted to address these issues, up until now, much of the data appears conflicting. However, recent work from our laboratories, in which human volunteers were fed highly oxidatively modified 15 N-labelled DNA demonstrates that diet does not appear to contribute to urinary levels of 8-hydroxyguanine and 7,8-dihydro-8-oxo-2'-deoxyguanosine. Furthermore, we propose that a number of literature reports form an argument against a contribution from cell death. Indeed we, and others, have presented evidence, which strongly suggests the involvement of cell death to be minimal. Taken together, these data would appear to rule out various confounding factors, leaving DNA repair pathways as the principal source of urinary purine, if not DNA, lesions enabling such measurements to be used as indicators of repair

  2. The (6-4) Dimeric Lesion as a DNA Photosensitizer

    OpenAIRE

    Vendrell Criado, Victoria; Rodríguez Muñiz, Gemma María; Lhiaubet ., Virginie Lyria; Cuquerella Alabort, Maria Consuelo; Miranda Alonso, Miguel Ángel

    2016-01-01

    [EN] Based on our previous investigations into the photophysical properties of the 5-methyl-2-pyrimidone (Pyo) chromophore, we now extend our studies to the photobehavior of the dimeric (6-4) thymine photoproducts (6-4 PP) to evaluate their capability to act as instrinsic DNA photosensitizers. The lesion presents significant absorption in the UVB/UVA region, weak fluorescence emission, a singlet-excited-state energy of approximately 351 kJ mol(-1), and a triplet-excited-state energy of 297 kJ...

  3. The (6-4) Dimeric Lesion as a DNA Photosensitizer.

    Science.gov (United States)

    Vendrell-Criado, Victoria; Rodríguez-Muñiz, Gemma M; Lhiaubet-Vallet, Virginie; Cuquerella, M Consuelo; Miranda, Miguel A

    2016-07-04

    Based on our previous investigations into the photophysical properties of the 5-methyl-2-pyrimidone (Pyo) chromophore, we now extend our studies to the photobehavior of the dimeric (6-4) thymine photoproducts (6-4 PP) to evaluate their capability to act as instrinsic DNA photosensitizers. The lesion presents significant absorption in the UVB/UVA region, weak fluorescence emission, a singlet-excited-state energy of approximately 351 kJ mol(-1) , and a triplet-excited-state energy of 297 kJ mol(-1) . Its triplet transient absorption has a maximum at 420-440 nm, a lifetime of around 7 μs, and a high formation quantum yield, ΦISC =0.86. This species is efficiently quenched by thymidine. Its DNA photosensitizing properties are demonstrated by a series of experiments run on a pBR322 plasmid. The lesion photoinduces both single-strand breaks and the formation of cyclobutane thymine dimers. Altogether, these results show that, the substitution of the pyrimidone ring at C4 by a 5-hydroxy-5,6-dihydrothymine does not cancel out the photosensitization properties of the chromophore. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. Poly(ADP-ribose) polymerase 1 escorts XPC to UV-induced DNA lesions during nucleotide excision repair.

    Science.gov (United States)

    Robu, Mihaela; Shah, Rashmi G; Purohit, Nupur K; Zhou, Pengbo; Naegeli, Hanspeter; Shah, Girish M

    2017-08-15

    Xeroderma pigmentosum C (XPC) protein initiates the global genomic subpathway of nucleotide excision repair (GG-NER) for removal of UV-induced direct photolesions from genomic DNA. The XPC has an inherent capacity to identify and stabilize at the DNA lesion sites, and this function is facilitated in the genomic context by UV-damaged DNA-binding protein 2 (DDB2), which is part of a multiprotein UV-DDB ubiquitin ligase complex. The nuclear enzyme poly(ADP-ribose) polymerase 1 (PARP1) has been shown to facilitate the lesion recognition step of GG-NER via its interaction with DDB2 at the lesion site. Here, we show that PARP1 plays an additional DDB2-independent direct role in recruitment and stabilization of XPC at the UV-induced DNA lesions to promote GG-NER. It forms a stable complex with XPC in the nucleoplasm under steady-state conditions before irradiation and rapidly escorts it to the damaged DNA after UV irradiation in a DDB2-independent manner. The catalytic activity of PARP1 is not required for the initial complex formation with XPC in the nucleoplasm but it enhances the recruitment of XPC to the DNA lesion site after irradiation. Using purified proteins, we also show that the PARP1-XPC complex facilitates the handover of XPC to the UV-lesion site in the presence of the UV-DDB ligase complex. Thus, the lesion search function of XPC in the genomic context is controlled by XPC itself, DDB2, and PARP1. Our results reveal a paradigm that the known interaction of many proteins with PARP1 under steady-state conditions could have functional significance for these proteins.

  5. Role of DNA lesions and DNA repair in mutagenesis by carcinogens in diploid human fibroblasts

    International Nuclear Information System (INIS)

    Maher, V.M.; McCormick, J.J.

    1986-01-01

    The authors investigated the cytotoxicity, mutagenicity, and transforming activity of carcinogens and radiation in diploid human fibroblasts, using cells which differ in their DNA repair capacity. The results indicate that cell killing and induction of mutations are correlated with the number of specific lesions remaining unrepaired in the cells at a particular time posttreatment. DNA excision repair acts to eliminate potentially cytotoxic and mutagenic (and transforming) damage from DNA before these can be converted into permanent cellular effects. Normal human fibroblasts were derived from skin biopsies or circumcision material. Skin fibroblasts from xeroderma pigmentosum (XP) patients provided cells deficient in nucleotide excision repair of pyrimidine dimers or DNA adducts formed by bulky ring structures. Cytotoxicity was determined from loss of ability to form a colony. The genetic marker used was resistance to 6-thioguanine (TG). Transformation was measured by determining the frequency of anchorage-independent cells

  6. Traveling Rocky Roads: The Consequences of Transcription-Blocking DNA Lesions on RNA Polymerase II.

    Science.gov (United States)

    Steurer, Barbara; Marteijn, Jurgen A

    2017-10-27

    The faithful transcription of eukaryotic genes by RNA polymerase II (RNAP2) is crucial for proper cell function and tissue homeostasis. However, transcription-blocking DNA lesions of both endogenous and environmental origin continuously challenge the progression of elongating RNAP2. The stalling of RNAP2 on a transcription-blocking lesion triggers a series of highly regulated events, including RNAP2 processing to make the lesion accessible for DNA repair, R-loop-mediated DNA damage signaling, and the initiation of transcription-coupled DNA repair. The correct execution and coordination of these processes is vital for resuming transcription following the successful repair of transcription-blocking lesions. Here, we outline recent insights into the molecular consequences of RNAP2 stalling on transcription-blocking DNA lesions and how these lesions are resolved to restore mRNA synthesis. Copyright © 2016 The Author(s). Published by Elsevier Ltd.. All rights reserved.

  7. Lesion Orientation of O4-Alkylthymidine Influences Replication by Human DNA Polymerase η

    OpenAIRE

    O’Flaherty, D. K.; Patra, A.; Su, Y.; Guengerich, F. P.; Egli, M.; Wilds, C. J.

    2016-01-01

    DNA lesions that elude repair may undergo translesion synthesis catalyzed by Y-family DNA polymerases. O4-Alkylthymidines, persistent adducts that can result from carcinogenic agents, may be encountered by DNA polymerases. The influence of lesion orientation around the C4-O4 bond on processing by human DNA polymerase η (hPol η) was studied for oligonucleotides containing O4-methylthymidine, O4-ethylthymidine, and analogs restricting the O4-methylene group in an anti-orientation. Primer extens...

  8. Molecular dynamics of formation of TD lesioned DNA complexed with repair enzyme - onset of the enzymatic repair process

    Energy Technology Data Exchange (ETDEWEB)

    Pinak, Miroslav [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    1999-12-01

    To describe the first step of the enzymatic repair process (formation of complex enzyme-DNA), in which the thymine dimer (TD) part is removed from DNA, the 500 picosecond (ps) molecular dynamics (MD) simulation of TD lesioned DNA and part of repair enzyme cell (inclusive of catalytic center - Arg-22, Glu-23, Arg-26 and Thr-2) was performed. TD is UV originated lesion in DNA and T4 Endonuclease V is TD specific repair enzyme. Both molecules were located in the same simulation cell and their relative movement was examined. During the simulation the research was focused on the role of electrostatic energy in formation of complex enzyme-DNA. It is found, that during the first 100 ps of MD, the part of enzyme approaches the DNA surface at the TD lesion, interacts extensively by electrostatic and van der Walls interactions with TD part of DNA and forms complex that lasts stabile for 500 ps of MD. In the beginning of MD, the positive electrostatic interaction energy between part of enzyme and TD ({approx} +10 kcal/mol) drives enzyme towards the DNA molecule. Water-mediated hydrogen bonds between enzyme and DNA help to keep complex stabile. As a reference, the MD simulation of the identical system with native DNA molecule (two native thymines (TT) instead of TD) was performed. In this system the negative electrostatic interaction energy between part of enzyme and TT ({approx} -11 kcal/mol), in contrary to the positive one in the system with TD, doesn't drive enzyme towards DNA and complex is not formed. (author)

  9. Molecular dynamics of formation of TD lesioned DNA complexed with repair enzyme - onset of the enzymatic repair process

    International Nuclear Information System (INIS)

    Pinak, Miroslav

    1999-12-01

    To describe the first step of the enzymatic repair process (formation of complex enzyme-DNA), in which the thymine dimer (TD) part is removed from DNA, the 500 picosecond (ps) molecular dynamics (MD) simulation of TD lesioned DNA and part of repair enzyme cell (inclusive of catalytic center - Arg-22, Glu-23, Arg-26 and Thr-2) was performed. TD is UV originated lesion in DNA and T4 Endonuclease V is TD specific repair enzyme. Both molecules were located in the same simulation cell and their relative movement was examined. During the simulation the research was focused on the role of electrostatic energy in formation of complex enzyme-DNA. It is found, that during the first 100 ps of MD, the part of enzyme approaches the DNA surface at the TD lesion, interacts extensively by electrostatic and van der Walls interactions with TD part of DNA and forms complex that lasts stabile for 500 ps of MD. In the beginning of MD, the positive electrostatic interaction energy between part of enzyme and TD (∼ +10 kcal/mol) drives enzyme towards the DNA molecule. Water-mediated hydrogen bonds between enzyme and DNA help to keep complex stabile. As a reference, the MD simulation of the identical system with native DNA molecule (two native thymines (TT) instead of TD) was performed. In this system the negative electrostatic interaction energy between part of enzyme and TT (∼ -11 kcal/mol), in contrary to the positive one in the system with TD, doesn't drive enzyme towards DNA and complex is not formed. (author)

  10. Towards observing the encounter of the T7 DNA replication fork with a lesion site at the Single molecule level

    KAUST Repository

    Shirbini, Afnan

    2017-05-01

    Single-molecule DNA flow-stretching assays have been a powerful approach to study various aspects on the mechanism of DNA replication for more than a decade. This technique depends on flow-induced force on a bead attached to a surface-tethered DNA. The difference in the elastic property between double-strand DNA (long) and single-strand DNA (short) at low regime force allows the observation of the beads motion when the dsDNA is converted to ssDNA by the replisome machinery during DNA replication. Here, I aim to develop an assay to track in real-time the encounter of the bacteriophage T7 replisome with abasic lesion site inserted on the leading strand template. I optimized methods to construct the DNA substrate that contains the abasic site and established the T7 leading strand synthesis at the single molecule level. I also optimized various control experiments to remove any interference from the nonspecific interactions of the DNA with the surface. My work established the foundation to image the encounter of the T7 replisome with abasic site and to characterize how the interactions between the helicase and the polymerase could influence the polymerase proofreading ability and its direct bypass of this highly common DNA damage type.

  11. Detection and repair of a UV-induced photosensitive lesion in the DNA of human cells

    International Nuclear Information System (INIS)

    Francis, A.A.; Regan, J.D.

    1986-01-01

    Irradiation with UV light results in damage to the DNA of human cells. The most numerous lesions are pyrimidine dimers; however, other lesions are known to occur and may contribute to the overall deleterious effect of UV irradiation. The authors have observed evidence of a UV-induced lesion other than pyrimidine dimers in the DNA of human cells by measuring DNA strand breaks induced by irradiating with 313-nm light following UV (254-nm) irradiation. The data suggest that, in normal cells, the lesion responsible for this effect is rapidly repaired or altered; whereas, in xeroderma pigmentosum variant cells it seems to remain unchanged. Some change apparently occurs in the DNA of xeroderma pigmentosum group A cells which results in an increase in photolability. These data indicate a deficiency in DNA repair of xeroderma pigmentosum variant cells as well as in xeroderma pigmentosum group A cells. (Auth.)

  12. Measurement and meaning of oxidatively modified DNA lesions in urine

    DEFF Research Database (Denmark)

    Cooke, Marcus S; Olinski, Ryszard; Loft, Steffen

    2008-01-01

    and cell death have minimal, if any, influence upon urinary levels of 8-oxodG and 8-oxo-7,8-dihydroguanine, although this should be assessed on a lesion-by-lesion basis. Broadly speaking, there is consensus between chromatographic techniques; however, ELISA approaches continue to overestimate 8-oxod...

  13. DNA Damage by Ionizing Radiation: Tandem Double Lesions by Charged Particles

    Science.gov (United States)

    Huo, Winifred M.; Chaban, Galina M.; Wang, Dunyou; Dateo, Christopher E.

    2005-01-01

    Oxidative damages by ionizing radiation are the source of radiation-induced carcinogenesis, damage to the central nervous system, lowering of the immune response, as well as other radiation-induced damages to human health. Monte Carlo track simulations and kinetic modeling of radiation damages to the DNA employ available molecular and cellular data to simulate the biological effect of high and low LET radiation io the DNA. While the simulations predict single and double strand breaks and base damages, so far all complex lesions are the result of stochastic coincidence from independent processes. Tandem double lesions have not yet been taken into account. Unlike the standard double lesions that are produced by two separate attacks by charged particles or radicals, tandem double lesions are produced by one single attack. The standard double lesions dominate at the high dosage regime. On the other hand, tandem double lesions do not depend on stochastic coincidences and become important at the low dosage regime of particular interest to NASA. Tandem double lesions by hydroxyl radical attack of guanine in isolated DNA have been reported at a dosage of radiation as low as 10 Gy. The formation of two tandem base lesions was found to be linear with the applied doses, a characteristic of tandem lesions. However, tandem double lesions from attack by a charged particle have not been reported.

  14. Stalled repair of lesions when present within a clustered DNA damage site

    International Nuclear Information System (INIS)

    Lomax, M.E.; Cunniffe, S.; O'Neill, P.

    2003-01-01

    Ionising radiation produces clustered DNA damages (two or more lesions within one or two helical turns of the DNA) which could challenge the repair mechanism(s) of the cell. Using purified base excision repair (BER) enzymes and synthetic oligonucleotides a number of recent studies have established the excision of a lesion within clustered damage sites is compromised. Evidence will be presented that the efficiency of repair of lesions within a clustered DNA damage site is reduced, relative to that of the isolated lesions, since the lifetime of both lesions is extended by up to four fold. Simple clustered damage sites, comprised of single-strand breaks, abasic sites and base damages, one or five bases 3' or 5' to each other, were synthesised in oligonucleotides and repair carried out in mammalian cell nuclear extracts. The rate of repair of the single-strand break/abasic site within these clustered damage sites is reduced, mainly due to inhibition of the DNA ligase. The mechanism of repair of the single-strand break/abasic site shows some asymmetry. Repair appears to be by the short-patch BER pathway when the lesions are 5' to each other. In contrast, when the lesions are 3' to each other repair appears to proceed along the long-patch BER pathway. The lesions within the cluster are processed sequentially, the single-strand break/abasic site being repaired before excision of 8-oxoG, limiting the formation of double-strand breaks to <2%. Stalled processing of clustered DNA damage extends the lifetime of the lesions to an extent that could have biological consequences, e.g. if the lesions are still present during transcription and/or at replication mutations could arise

  15. Are lesions induced by ionizing radiation direct blocks to DNA chain elongation

    International Nuclear Information System (INIS)

    Painter, R.B.

    1983-01-01

    Ionizing radiation blocks DNA chain elongation in normal diploid fibroblasts but not in fibroblasts from patients with ataxia-telangiectasia, even though there are no differences in the damage induced between the two cell types. This difference suggests that radiation-induced lesions in DNA are not themselves blocks to chain elongation in ataxia cells and raises the possibility that in normal cells a mediator exists between DNA damage and chain termination

  16. On the biophysical interpretation of lethal DNA lesions induced by ionising radiation

    Czech Academy of Sciences Publication Activity Database

    Kundrát, Pavel; Stewart, R.D.

    2006-01-01

    Roč. 122, 1-4 (2006), s. 169-172 ISSN 0144-8420 R&D Projects: GA ČR GA202/05/2728 Institutional research plan: CEZ:AV0Z10100502 Keywords : clustered DNA lesions * V79 cells * proton tracks * DNA damage * DNA repair * radiobiological modelling Subject RIV: BF - Elementary Particles and High Energy Physics Impact factor: 0.446, year: 2006

  17. Fundamental study of the radiation monitoring system based on evaluation of DNA lesions

    International Nuclear Information System (INIS)

    Shimizu, K.; Matuo, Y.; Izumi, Y.; Ikeda, T.

    2011-01-01

    The biological dosemeter that measures biological responses to ionising radiation is useful for radiation protection. This paper presents the development and characterisation of a gamma ray irradiation dosimetry system based on real-time PCR (polymerase chain reaction) methodology. Real-time PCR is used to amplify and simultaneously quantify a targeted DNA molecule. If there are no limitations due to limiting substrates or reagents, at each extension step, the amount of DNA target is doubled, leading to exponential (geometric) amplification of the specific DNA fragment. The essential point of this assay is that DNA lesions caused by ionising radiation block DNA synthesis by DNA polymerase, resulting in a decrease in the amplification of a damaged DNA template compared with that of non-damaged DNA templates. (authors)

  18. Pyrimidine dimers are not the principal pre-mutagenic lesions induced in lambda phage DNA by ultraviolet light

    International Nuclear Information System (INIS)

    Wood, R.D.

    1985-01-01

    Experiments were performed to examine the role of cyclobutyl pyrimidine dimers in the process of mutagenesis by ultraviolet light. Lambda phage DNA was irradiated with u.v. and then incubated with an Escherichia coli photoreactivating enzyme, which monomerizes cyclobutyl pyrimidine dimers upon exposure to visible light. The photoreactivated DNA was packaged into lambda phage particles, which were used to infect E. coli uvr - host cells that had been induced for SOS functions by ultraviolet irradiation. Photoreactivation removed most toxic lesions from irradiated phage, but did not change the frequency of induction of mutations to the clear-plaque phenotype. This implies that cyclobutyl pyrimidine dimers can be lethal, but usually do not serve as sites of mutations in the phage. The DNA sequences of mutants, derived from photoreactivated DNA showed that almost two-thirds (16/28) were transitions, the same fraction found for u.v. mutagenesis without photoreactivation. Thus the lesion inducing transitions is not the cyclobutyl pyrimidine dimer. Photoreactivation of SOS-induced host cells before infection with u.v.-irradiated phage reduced mutagenesis substantially. In this case, photoreversal of cyclobutyl dimers serves to reduce expression of the SOS functions that are required in targeted u.v. mutagenesis. (author)

  19. Clustered DNA lesions containing 5-formyluracil and AP site: repair via the BER system.

    Directory of Open Access Journals (Sweden)

    Ekaterina A Belousova

    Full Text Available Lesions in the DNA arise under ionizing irradiation conditions or various chemical oxidants as a single damage or as part of a multiply damaged site within 1-2 helical turns (clustered lesion. Here, we explored the repair opportunity of the apurinic/apyrimidinic site (AP site composed of the clustered lesion with 5-formyluracil (5-foU by the base excision repair (BER proteins. We found, that if the AP site is shifted relative to the 5-foU of the opposite strand, it could be repaired primarily via the short-patch BER pathway. In this case, the cleavage efficiency of the AP site-containing DNA strand catalyzed by human apurinic/apyrimidinic endonuclease 1 (hAPE1 decreased under AP site excursion to the 3'-side relative to the lesion in the other DNA strand. DNA synthesis catalyzed by DNA polymerase lambda was more accurate in comparison to the one catalyzed by DNA polymerase beta. If the AP site was located exactly opposite 5-foU it was expected to switch the repair to the long-patch BER pathway. In this situation, human processivity factor hPCNA stimulates the process.

  20. Lesion measurement in non-radioactive DNA by quantitative gel electrophoresis

    International Nuclear Information System (INIS)

    Sutherland, J.C.; Chen, Chun Zhang; Emrick, A.; Hacham, H; Monteleone, D.; Ribeiro, E.; Trunk, J.; Sutherland, B.M.

    1989-01-01

    The gel electrophoresis method developed during the past ten years in our laboratories makes possible the quantitation of UV induced pyrimidine dimers, gamma ray induced single- and double-strand breaks and many other types of lesions in nanogram quantities of DNA. The DNA does not have to be labeled with radionuclides or of a particular conformation, thus facilitating the use of the method in measuring damage levels and repair rates in the DNA of intact organisms -- including man. The gel method can quantitate any lesion in DNA that either is, or can be converted to a single- or double-strand break. The formation of a strand break produces two shorter DNA molecules for each molecule that existed before the treatment that produced the break. Determining the number of breaks, and hence the number of lesions, becomes a matter of comparing the average lengths of molecules in samples differing only in lesion-induced breaks. This requires that we determine the distribution of mass of DNA on a gel as a function of its distance of migration and also the dispersion function of its distance of migration and also the dispersion function (the relationship between molecular length and distance of migration) in the gel electrophoresis system. 40 refs., 5 figs

  1. Defective DNA cross-link removal in Chinese hamster cell mutants hypersensitive to bifunctional alkylating agents

    International Nuclear Information System (INIS)

    Hoy, C.A.; Thompson, L.H.; Mooney, C.L.; Salazar, E.P.

    1985-01-01

    DNA repair-deficient mutants from five genetic complementation groups isolated previously from Chinese hamster cells were assayed for survival after exposure to the bifunctional alkylating agents mitomycin C or diepoxybutane. Groups 1, 3, and 5 exhibited 1.6- to 3-fold hypersensitivity compared to the wild-type cells, whereas Groups 2 and 4 exhibited extraordinary hypersensitivity. Mutants from Groups 1 and 2 were exposed to 22 other bifunctional alkylating agents in a rapid assay that compared cytotoxicity of the mutants to the wild-type parental strain, AA8. With all but two of the compounds, the Group 2 mutant (UV4) was 15- to 60-fold more sensitive than AA8 or the Group 1 mutant (UV5). UV4 showed only 6-fold hypersensitivity to quinacrine mustard. Alkaline elution measurements showed that this compound produced few DNA interstrand cross-links but numerous strand breaks. Therefore, the extreme hypersensitivity of mutants from Groups 2 and 4 appeared specific for compounds the main cytotoxic lesions of which were DNA cross-links. Mutant UV5 was only 1- to 4-fold hypersensitive to all the compounds. Although the initial number of cross-links was similar for the three cell lines, the efficiency of removal of cross-links was lowest in UV4 and intermediate in UV5. These results suggest that the different levels of sensitivity are specifically related to different efficiencies of DNA cross-link removal. The phenotype of hypersensitivity to both UV radiation and cross-link damage exhibited by the mutants in Groups 2 and 4 appears to differ from those of the known human DNA repair syndromes

  2. The effect of temperature and wavelength on production and photolysis of a UV-induced photosensitive DNA lesion which is not repaired in xeroderma pigmentosum variant cells

    International Nuclear Information System (INIS)

    Francis, A.A.; Carrier, W.L.; Regan, J.D.

    1988-01-01

    Ultraviolet light causes a type of damage to the DNA of human cells that results in a DNA strand break upon subsequent irradiation with wavelengths around 300 nm. This DNA damage disappears from normal human fibroblasts within 5 h, but not from pyrimidine dimer excision repair deficient xeroderma pigmentosum group A cells or from excision proficient xeroderma pigmentosum variant cells. The apparent lack of repair of the ultraviolet light DNA damage described here may contribute to the cancer prone nature of xeroderma pigmentosum variant individuals. These experiments show that the same amount of damage was produced at 0 0 C and 37 0 C indicating a photodynamic effect and not an enzymatic reaction. The disappearance of the photosensitive lesions from the DNA is probably enzymatic since none of the damage was removed at 0 0 C. Both the formation of the lesion and its photolysis by near ultraviolet light were wavelength dependent. An action spectrum for the formation of photosensitive lesions was similar to that for the formation of pyrimidine dimers and (6-4) photoproducts and included wavelengths found in sunlight. The DNA containing the lesions was sensitive to wavelengths from 304 to 340 nm with a maximum at 313 to 317 nm. This wavelength dependence of photolysis is similar to the absorption and photolysis spectra of the pyrimidine (6-4) photoproducts. (author)

  3. Liquid biopsy in the diagnosis of HPV DNA in breast lesions.

    Science.gov (United States)

    Carolis, Sabrina De; Pellegrini, Alice; Santini, Donatella; Ceccarelli, Claudio; De Leo, Antonio; Alessandrini, Federica; Arienti, Chiara; Pignatta, Sara; Tesei, Anna; Mantovani, Vilma; Zamagni, Claudio; Taffurelli, Mario; Sansone, Pasquale; Bonafé, Massimiliano; Cricca, Monica

    2018-02-01

    HPV DNA has never been investigated in nipple discharges (ND) and serum-derived extracellular vesicles, although its presence has been reported in ductal lavage fluids and blood specimens. We analyzed 50 ND, 22 serum-derived extracellular vesicles as well as 51 pathologic breast tissues for the presence of 16 HPV DNA types. We show that the presence of HPV DNA in the ND is predictive of HPV DNA-positive breast lesions and that HPV DNA is more represented in intraductal papillomas. We also show the presence of HPV DNA in the serum-derived extracellular vesicles. Our data supports the use of liquid biopsy to detect HPV DNA in breast pathology.

  4. Removal of oxygen free-radical-induced 5′,8-purine cyclodeoxynucleosides from DNA by the nucleotide excision-repair pathway in human cells

    Science.gov (United States)

    Kuraoka, Isao; Bender, Christina; Romieu, Anthony; Cadet, Jean; Wood, Richard D.; Lindahl, Tomas

    2000-01-01

    Exposure of cellular DNA to reactive oxygen species generates several classes of base lesions, many of which are removed by the base excision-repair pathway. However, the lesions include purine cyclodeoxynucleoside formation by intramolecular crosslinking between the C-8 position of adenine or guanine and the 5′ position of 2-deoxyribose. This distorting form of DNA damage, in which the purine is attached by two covalent bonds to the sugar-phosphate backbone, occurs as distinct diastereoisomers. It was observed here that both diastereoisomers block primer extension by mammalian and microbial replicative DNA polymerases, using DNA with a site-specific purine cyclodeoxynucleoside residue as template, and consequently appear to be cytotoxic lesions. Plasmid DNA containing either the 5′R or 5′S form of 5′,8-cyclo-2-deoxyadenosine was a substrate for the human nucleotide excision-repair enzyme complex. The R diastereoisomer was more efficiently repaired than the S isomer. No correction of the lesion by direct damage reversal or base excision repair was detected. Dual incision around the lesion depended on the core nucleotide excision-repair protein XPA. In contrast to several other types of oxidative DNA damage, purine cyclodeoxynucleosides are chemically stable and would be expected to accumulate at a slow rate over many years in the DNA of nonregenerating cells from xeroderma pigmentosum patients. High levels of this form of DNA damage might explain the progressive neurodegeneration seen in XPA individuals. PMID:10759556

  5. Effect of radiomodifying agents on the ratios of X-ray-induced lesions in cellular DNA: use in lethal lesion determination

    International Nuclear Information System (INIS)

    Radford, I.R.

    1986-01-01

    The effect of three radiomodifying agents, cysteamine, hyperthermia, and hypoxia, on the induction of the major classes of X-ray-induced DNA lesions, was studied using mouse L cells and Chinese hamster V79 cells. The use of filter elution techniques allowed most of these studies to be conducted at X-ray doses within the survival-curve range. Cysteamine was found to protect against DNA single-strand breakage (ssb), DNA base damage, and DNA-protein crosslinkage. Hyperthermia had no effect on the level of DNA ssb or DNA base damage, but in L cells (but not in V79 cells) it increased the level of DNA-protein crosslinkage relative to DNA ssb. Hypoxia protected against DNA ssb, had no significant effect on the level of DNA base damage, and enhanced the level of DNA-protein crosslinkage relative to DNA ssb. These results support the previous suggestion that the X-ray-induced lethal lesion is DNA double-strand breakage. Implications of these findings for the mechanisms of formation of X-ray-induced DNA lesions are also discussed. (author)

  6. Identification of potentially cytotoxic lesions induced by UVA photoactivation of DNA 4-thiothymidine in human cells

    Science.gov (United States)

    Reelfs, Olivier; Macpherson, Peter; Ren, Xiaolin; Xu, Yao-Zhong; Karran, Peter; Young, Antony R.

    2011-01-01

    Photochemotherapy—in which a photosensitizing drug is combined with ultraviolet or visible radiation—has proven therapeutic effectiveness. Existing approaches have drawbacks, however, and there is a clinical need to develop alternatives offering improved target cell selectivity. DNA substitution by 4-thiothymidine (S4TdR) sensitizes cells to killing by ultraviolet A (UVA) radiation. Here, we demonstrate that UVA photoactivation of DNA S4TdR does not generate reactive oxygen or cause direct DNA breakage and is only minimally mutagenic. In an organotypic human skin model, UVA penetration is sufficiently robust to kill S4TdR-photosensitized epidermal cells. We have investigated the DNA lesions responsible for toxicity. Although thymidine is the predominant UVA photoproduct of S4TdR in dilute solution, more complex lesions are formed when S4TdR-containing oligonucleotides are irradiated. One of these, a thietane/S5-(6-4)T:T, is structurally related to the (6-4) pyrimidine:pyrimidone [(6-4) Py:Py] photoproducts induced by UVB/C radiation. These lesions are detectable in DNA from S4TdR/UVA-treated cells and are excised from DNA more efficiently by keratinocytes than by leukaemia cells. UVA irradiation also induces DNA interstrand crosslinking of S4TdR-containing duplex oligonucleotides. Cells defective in repairing (6-4) Py:Py DNA adducts or processing DNA crosslinks are extremely sensitive to S4TdR/UVA indicating that these lesions contribute significantly to S4TdR/UVA cytotoxicity. PMID:21890905

  7. Miscoding and mutagenic properties of 8-oxoguanine and abasic sites: Ubiquitous lesions in damaged DNA

    International Nuclear Information System (INIS)

    Grollman, A.P.; Takeshita, Masaru

    1995-01-01

    More than twenty oxidatively-damaged bases, including 8-oxoguanine, have been found to occur in genomic DNA. Some of these lesions block DNA replication and are potentially lethal; others generate mutations which can initiate carcinogenesis and promote cellular aging. In this report, the authors focus attention on the mutagenicity and repair of 8-oxoguanine. Kasai and Nishimura's discovery that hydroxyl radicals react with guanine residues in DNA to form 8-oxoguanine and the development of sensitive methods for the detection and quantitation of this modified base led to the observation that approximately 1 in 10 5 guanine residues in mammalian DNA are oxidized at the C-8 position. DNA containing 8-oxoguanine and synthetic analogs of the abasic site have been used to investigate the miscoding and mutagenic potential of these ubiquitous lesions. Studies in the laboratory were facilitated by the development of solid state synthetic methods by which these lesions could be introduced at defined positions in DNA. In this paper, the authors review studies in which 8-oxoguanine and abasic sites have been used in model systems to explore various early events in the replication of selectively damaged DNA

  8. Kinetic Analysis of the Bypass of a Bulky DNA Lesion Catalyzed by Human Y-family DNA Polymerases

    Science.gov (United States)

    Sherrer, Shanen M.; Sanman, Laura E.; Xia, Cynthia X.; Bolin, Eric R.; Malik, Chanchal K.; Efthimiopoulos, Georgia; Basu, Ashis K.; Suo, Zucai

    2012-01-01

    1-Nitropyrene (1-NP), a mutagen and potential carcinogen, is the most abundant nitro polyaromatic hydrocarbon in diesel exhaust, which reacts with DNA to form predominantly N-(deoxyguanosin-8-yl)-1-aminopyrene (dGAP). If not repaired, this DNA lesion is presumably bypassed in vivo by any of human Y-family DNA polymerases kappa (hPolκ), iota (hPolτ), eta (hPolη), and Rev1 (hRev1). Our running start assays demonstrated that each of these enzymes was indeed capable of traversing a site-specifically placed dGAP on a synthetic DNA template but hRev1 was stopped after lesion bypass. The time required to bypass 50% of the dGAP sites (t50bypass ) encountered by hPolη, hPolκ and hPolτ was determined to be 2.5 s, 4.1 s, and 106.5 s, respectively. The efficiency order of catalyzing translesion synthesis of dGAP (hPolη > hPolκ > hPolτ >> hRev1) is the same as the order for these human Y-family enzymes to elongate undamaged DNA. Although hPolη bypassed dGAP efficiently, replication by both hPolκ and hPolτ was strongly stalled at the lesion site and at a site immediately downstream from dGAP. By employing pre-steady state kinetic methods, a kinetic basis was established for polymerase pausing at these DNA template sites. Besides efficiency of bypass, the fidelity of those low-fidelity polymerases at these pause sites was also significantly decreased. Thus, if the translesion DNA synthesis of dGAP in vivo is catalyzed by a human Y-family DNA polymerase, e.g. hPolη, the process is certainly mutagenic. PMID:22324639

  9. DNA lesions induced by replication stress trigger mitotic aberration and tetraploidy development.

    Directory of Open Access Journals (Sweden)

    Yosuke Ichijima

    Full Text Available During tumorigenesis, cells acquire immortality in association with the development of genomic instability. However, it is still elusive how genomic instability spontaneously generates during the process of tumorigenesis. Here, we show that precancerous DNA lesions induced by oncogene acceleration, which induce situations identical to the initial stages of cancer development, trigger tetraploidy/aneuploidy generation in association with mitotic aberration. Although oncogene acceleration primarily induces DNA replication stress and the resulting lesions in the S phase, these lesions are carried over into the M phase and cause cytokinesis failure and genomic instability. Unlike directly induced DNA double-strand breaks, DNA replication stress-associated lesions are cryptogenic and pass through cell-cycle checkpoints due to limited and ineffective activation of checkpoint factors. Furthermore, since damaged M-phase cells still progress in mitotic steps, these cells result in chromosomal mis-segregation, cytokinesis failure and the resulting tetraploidy generation. Thus, our results reveal a process of genomic instability generation triggered by precancerous DNA replication stress.

  10. Removal of focal atheromatous lesions by angioscopically guided high-speed rotary atherectomy. Preliminary experimental observations

    International Nuclear Information System (INIS)

    Ahn, S.S.; Auth, D.; Marcus, D.R.; Moore, W.S.

    1988-01-01

    A new high-speed rotary atherectomy device, inserted over a guide wire and directed with an angioscope, offers the potential of restoring patency of outflow vessels by boring out the atheromatous lesion of the orifices of runoff vessels. The device was tested on 68 cadaver arteries with atheromatous lesions involving the superficial femoral, popliteal, and tibial arteries. This was performed with either free segments or in situ with the device placed through a popliteal arteriotomy. The gross results of rotary atherectomy were assessed by angioscopy, angiography, or both. The luminal surfaces were studied with scanning electron microscopy and transverse sections of vessels were studied with light microscopy. The pulverized atheroma, in colloidal suspension, was analyzed for particle size by Coulter counter. The effect of a colloidal suspension of atheromatous particles on distal capillary circulation was measured in animal experiments. Obstructive lesions were successfully removed in 36 of 37 stenotic arteries (97%) and 18 of 31 completely occluded arteries (58%), an overall efficacy of 54 of 68 (79%). In successfully atherectomized arteries, angioscopy and angiography demonstrated a widely patent, smooth, polished surface. Light microscopy demonstrated removal of the diseased intima with maintenance of the outer media and adventitia. The pulverized atheroma particles were generally smaller than red blood cells and injection of the colloidal atheroma into canine femoral arteries failed to produce local tissue injury. We conclude that in the human cadaver this atherectomy device effectively enlarges and recanalizes obstructed superficial femoral, popliteal, and tibial arteries

  11. Characterization of non-dimer DNA lesions and cellular damages caused by ultraviolet light

    International Nuclear Information System (INIS)

    Nakao, Kumi

    1989-01-01

    To understand the mechanisms of carcinogenicity and cytotoxicity induced by ultraviolet (UV) light, non-dimer DNA damages produced by near UV light (wave-length: 290∼320 nm) were examined by alkaline elution using Chinese hamster V-79 cells. UV exposure produced a dose-dependent induction of DNA single strand breaks and DNA-protein crosslinks. However, neither of these DNA lesions were repaired within a 24 hr incubation of the cells following UV exposure. Rather the number of these lesions increased. Also, UV exposure inhibited DNA and RNA synthesis. In addition, UV induced both cytotoxicity and chromosomal aberration. Electron spin resornance (ESR) studies showed that the exposure of cells to UV light resulted in the appearance of an ESR signal at -120degC. The roles of glutathione, vitamin E and vitamin B 2 , which were celluar antioxidant, on the induction of cytotoxicity by UV exposure were also examined. Pretreatment with vitamin E reduced the cytotoxicty caused by UV, whereas neither preteatment with vitamin B 2 nor the alteration of cellular gluthaione content affected the cytotoxicity. These results suggest that non-dimer DNA damages, such as DNA single strand breaks and DNA-protein crosslinks play an important role in inducing UV-carcinogenicity and UV-cytotoxicity, and that the mechanisms of these damages may be associated with the generation of free radicals. (author)

  12. Influence of DNA Lesions on Polymerase-Mediated DNA Replication at Single-Molecule Resolution.

    Science.gov (United States)

    Gahlon, Hailey L; Romano, Louis J; Rueda, David

    2017-11-20

    Faithful replication of DNA is a critical aspect in maintaining genome integrity. DNA polymerases are responsible for replicating DNA, and high-fidelity polymerases do this rapidly and at low error rates. Upon exposure to exogenous or endogenous substances, DNA can become damaged and this can alter the speed and fidelity of a DNA polymerase. In this instance, DNA polymerases are confronted with an obstacle that can result in genomic instability during replication, for example, by nucleotide misinsertion or replication fork collapse. It is important to know how DNA polymerases respond to damaged DNA substrates to understand the mechanism of mutagenesis and chemical carcinogenesis. Single-molecule techniques have helped to improve our current understanding of DNA polymerase-mediated DNA replication, as they enable the dissection of mechanistic details that can otherwise be lost in ensemble-averaged experiments. These techniques have also been used to gain a deeper understanding of how single DNA polymerases behave at the site of the damage in a DNA substrate. In this review, we evaluate single-molecule studies that have examined the interaction between DNA polymerases and damaged sites on a DNA template.

  13. Denture-related oral mucosal lesions among removable denture wearers ‎referred to clinics of Kerman, Iran

    Directory of Open Access Journals (Sweden)

    Shahrzad Taheri

    2016-05-01

    CONCLUSION: The finding of this study showed the prevalence of denture-related mucosal lesions is common. Dentists should be instruct the patients for removing the denture at night and routine follow-up visits.

  14. Genomic and functional integrity of the hematopoietic system requires tolerance of oxidative DNA lesions

    DEFF Research Database (Denmark)

    Martín-Pardillos, Ana; Tsaalbi-Shtylik, Anastasia; Chen, Si

    2017-01-01

    -distorting nucleotide lesions, resulted in the perinatal loss of hematopoietic stem cells, progressive loss of bone marrow, and fatal aplastic anemia between 3 and 4 months of age. This was associated with replication stress, genomic breaks, DNA damage signaling, senescence, and apoptosis in bone marrow. Surprisingly...

  15. Traveling Rocky Roads: The Consequences of Transcription-Blocking DNA Lesions on RNA Polymerase II

    NARCIS (Netherlands)

    B. Steurer (Barbara); J.A. Marteijn (Jurgen)

    2016-01-01

    textabstractThe faithful transcription of eukaryotic genes by RNA polymerase II (RNAP2) is crucial for proper cell function and tissue homeostasis. However, transcription-blocking DNA lesions of both endogenous and environmental origin continuously challenge the progression of elongating RNAP2. The

  16. DNA radio-induced tandem lesions: formation, introduction in oligonucleotides and repair

    International Nuclear Information System (INIS)

    Bourdat, Anne-Gaelle

    2000-01-01

    Cell killing induced by excited photosensitizers, ionizing radiation or radiomimetic drugs can not be only explained by the formation of single DNA lesions. Thus, multiply damaged sites, are likely to have harmful biological consequences. One example of tandem base damage induced by ".OH radical in X-irradiated aqueous solution of DNA oligomers is N-(2-deoxy-β-D-erythro-pentofuranosyl)-formyl-amine (dβF)/8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo). In order to investigate the biological significance of such a tandem lesion, both 8-oxodGuo and dβF were introduced in synthetic oligonucleotides at vicinal positions using the solid phase phosphoramidite method with the 'Pac phosphoramidite' chemistry. The purity of the synthetic DNA fragments and the integrity of modified nucleosides was confirmed using different complementary techniques: HPLC, PAGE, ESI MS, MALDI-TOF MS and capillary electrophoresis. Using the above synthetic substrates, investigations were carried out in order to determine the substrate specificity and the excision mechanism of three glycosylases involved in the base excision repair pathway: endonuclease III, Fpg and yOggl. Both tandem lesions were substrates for the BER enzymes. However, the tandem lesion are not completely excised by the repair enzymes. The rates of excision as inferred from the determination of the ratios of Vm/Km Michaelis kinetics constants were not found to be significantly affected by the presence of the tandem lesions. MALDI-TOF mass spectrometry was used in order to gain insights into mechanistic aspects of oligonucleotide cleavage by the BER enzymes. During in vitro DNA synthesis by Taq DNA polymerase, Klenow fragment exo- and DNA polymerase β, tandem base damage were found to block the progression of the enzymes. Finally, the level of tandem base damage in the DNA exposed to γ-ray using the liquid chromatography coupled to electro-spray ionization tandem mass spectrometry was determined. Both dβF-8-oxodGuo and 8

  17. DNA modification by sulfur mustards and nitrosoureas and repair of these lesions

    International Nuclear Information System (INIS)

    Ludlum, D.B.; Papirmeister, B.; Army Medical Research Institute of Chemical Defense, Aberdeen Proving Ground, MD)

    1986-01-01

    The nature and significance of DNA modifications caused by chloroethyl ethyl sulfide (CEES) is compared with those produced by chloroethyl cyclohexyl nitrosourea (CCNU). This comparison illustrates the differences in the kind of biological response which can arise from DNA modification by different agents and the role of DNA repair in determining this response. In particular, the ability of tumor cells to become resistant to therapeutic agents has some important implications for the ability of cells in general to tolerate environmental mutagens. DNA modification by CEES and CCNU can be viewed in the context of DNA modification caused by compounds which naturally react with DNA. For example, cycasin and S-adenosylmethionine both methylate DNA. Not surprisingly, a variety of repair mechanisms has evolved which serve to maintain the integrity of DNA in the presence of such naturally-occurring DNA modifiers. The ability of these enzymes to repair other DNA lesions is currently under active investigation as described here. 19 refs., 4 figs., 3 tabs

  18. Association of thymine glycol lesioned DNA with repair enzyme endonuclease III-molecular dynamics study

    International Nuclear Information System (INIS)

    Pinak, Miroslav

    2001-07-01

    The 2 nanoseconds molecular dynamics (MD) simulation has been performed for the system consisting of repair enzyme and DNA 30-mer with native thymine at position 16 replaced by thymine glycol (TG) solvated in water environment. After 950 picoseconds of MD the enzyme and DNA associated together to form complex that lasted stable up to 2 ns when simulation was terminated. At the contact area of enzyme and DNA there is glutamic acid located as close as 1.6 A to the C3' atom of phosphodiester bond of TG. Initial B-DNA molecule was bent and kinked at the TG during MD. This distortion caused that phosphodiester bond was easier accessible by amino acids of enzyme. The negative value of electrostatic energy (-26 kcal/mol) discriminates TG from nearly neutral native thymine and contributes to the specific recognition of this lesion. Higher number of close water molecules at TG site before formation of complex (compared with other nucleotides) indicates that glycosyl bond of the lesion is easily approached by repair enzyme during scanning of DNA surface and suggests the importance of specific hydration at the lesion during recognition process. (author)

  19. Association of thymine glycol lesioned DNA with repair enzyme endonuclease III-molecular dynamics study

    Energy Technology Data Exchange (ETDEWEB)

    Pinak, Miroslav [Japan Atomic Energy Research Inst., Tokai, Ibaraki (Japan). Tokai Research Establishment

    2001-07-01

    The 2 nanoseconds molecular dynamics (MD) simulation has been performed for the system consisting of repair enzyme and DNA 30-mer with native thymine at position 16 replaced by thymine glycol (TG) solvated in water environment. After 950 picoseconds of MD the enzyme and DNA associated together to form complex that lasted stable up to 2 ns when simulation was terminated. At the contact area of enzyme and DNA there is glutamic acid located as close as 1.6 A to the C3' atom of phosphodiester bond of TG. Initial B-DNA molecule was bent and kinked at the TG during MD. This distortion caused that phosphodiester bond was easier accessible by amino acids of enzyme. The negative value of electrostatic energy (-26 kcal/mol) discriminates TG from nearly neutral native thymine and contributes to the specific recognition of this lesion. Higher number of close water molecules at TG site before formation of complex (compared with other nucleotides) indicates that glycosyl bond of the lesion is easily approached by repair enzyme during scanning of DNA surface and suggests the importance of specific hydration at the lesion during recognition process. (author)

  20. Lesion Orientation of O4-Alkylthymidine Influences Replication by Human DNA Polymerase η.

    Science.gov (United States)

    O'Flaherty, D K; Patra, A; Su, Y; Guengerich, F P; Egli, M; Wilds, C J

    2016-08-01

    DNA lesions that elude repair may undergo translesion synthesis catalyzed by Y-family DNA polymerases. O 4 -Alkylthymidines, persistent adducts that can result from carcinogenic agents, may be encountered by DNA polymerases. The influence of lesion orientation around the C4- O 4 bond on processing by human DNA polymerase η (hPol η ) was studied for oligonucleotides containing O 4 -methylthymidine, O 4 -ethylthymidine, and analogs restricting the O 4 -methylene group in an anti -orientation. Primer extension assays revealed that the O 4 -alkyl orientation influences hPol η bypass. Crystal structures of hPol η •DNA•dNTP ternary complexes with O 4 -methyl- or O 4 -ethylthymidine in the template strand showed the nucleobase of the former lodged near the ceiling of the active site, with the syn - O 4 -methyl group engaged in extensive hydrophobic interactions. This unique arrangement for O 4 -methylthymidine with hPol η , inaccessible for the other analogs due to steric/conformational restriction, is consistent with differences observed for nucleotide incorporation and supports the concept that lesion conformation influences extension across DNA damage. Together, these results provide mechanistic insights on the mutagenicity of O 4 MedT and O 4 EtdT when acted upon by hPol η .

  1. Usefulness and Complications of Ultrasonography- Guided Vacuum Assisted Biopsy for the Removal of Benign Breast Lesions

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Keum Won; Cho, Young Jun; Hwang, Cheol Mog; Kim, Dae Ho; Oh, Kyoung Jin; Yoon, Dae Sung [Konyang University College of Medicine, Daejeon (Korea, Republic of); Kim, Kyu Soon [Eulji University College of Medicine, Daejeon (Korea, Republic of)

    2010-09-15

    To evaluate the usefulness and complications of ultrasonography (US)- guided vacuum assisted biopsy (VAB) for the removal of benign breast lesions, and the short- and long-term changes after VAB as shown on follow-up US. From January 2007 to May 2008, 110 sonographically benign lesions in 62 patients were sampled via US-guided VAB. We prospectively evaluated the sonographic findings 1 week and 6 months after VAB in all patients to determine the presence of residual tumors, hematomas and scarring. We evaluated the prevalence of hematoma, pain, skin dimpling, fibrotic scarring and residual tumors after US-guided VAB, and determined if correlation existed between complications, size of the lesions and lesion pathology. The age of the patients was 15-65 years, with a mean age of 36.5 years. The pathologic diagnoses were fibroadenomas (41.8%, n = 46), fibrocystic changes (30.9%, n = 34), fibroadenomatoid hyperplasias (13.6%, n = 15), fibroadenomatoid mastopathies (6.3%, n = 7), adenoses (3.6%, n = 4), hamartomas (1.8%, n = 2) and phyllodes tumors (1.8%, n = 2). Complications 1 week after the US-guided VAB included hematomas (n = 39, 35.4%), pain (n = 23, 20.9%), fibrotic scars (n = 26, 23.68%), residual tumors (n = 4, 3.6%) and skin dimplings (n = 4, 3.6%). Complications 6 months after the US-guided VAB included hematomas (n = 12, 10.9%), pain (n = 3 2.7%), fibrotic scars (n = 14, 12.7%), and residual tumors (n = 17, 15.4%). Residual tumor after US-guided VAB existed in association with 15.2% of fibroadenomas (7/46), 14.7% of fibrocystic changes (5/34), 13.3% of fibroadenomatoid hyperplasias (2/15), 25% of adenoses (1/4), and 100% of phyllodes tumors (2/2). US-guided VAB is an effective procedure for removal of benign breast lesion. Periodic follow up studies at 1 week and 6 months after the VAB are useful to assess Post-VAB complications

  2. Usefulness and Complications of Ultrasonography- Guided Vacuum Assisted Biopsy for the Removal of Benign Breast Lesions

    International Nuclear Information System (INIS)

    Kim, Keum Won; Cho, Young Jun; Hwang, Cheol Mog; Kim, Dae Ho; Oh, Kyoung Jin; Yoon, Dae Sung; Kim, Kyu Soon

    2010-01-01

    To evaluate the usefulness and complications of ultrasonography (US)- guided vacuum assisted biopsy (VAB) for the removal of benign breast lesions, and the short- and long-term changes after VAB as shown on follow-up US. From January 2007 to May 2008, 110 sonographically benign lesions in 62 patients were sampled via US-guided VAB. We prospectively evaluated the sonographic findings 1 week and 6 months after VAB in all patients to determine the presence of residual tumors, hematomas and scarring. We evaluated the prevalence of hematoma, pain, skin dimpling, fibrotic scarring and residual tumors after US-guided VAB, and determined if correlation existed between complications, size of the lesions and lesion pathology. The age of the patients was 15-65 years, with a mean age of 36.5 years. The pathologic diagnoses were fibroadenomas (41.8%, n = 46), fibrocystic changes (30.9%, n = 34), fibroadenomatoid hyperplasias (13.6%, n = 15), fibroadenomatoid mastopathies (6.3%, n = 7), adenoses (3.6%, n = 4), hamartomas (1.8%, n = 2) and phyllodes tumors (1.8%, n = 2). Complications 1 week after the US-guided VAB included hematomas (n = 39, 35.4%), pain (n = 23, 20.9%), fibrotic scars (n = 26, 23.68%), residual tumors (n = 4, 3.6%) and skin dimplings (n = 4, 3.6%). Complications 6 months after the US-guided VAB included hematomas (n = 12, 10.9%), pain (n = 3 2.7%), fibrotic scars (n = 14, 12.7%), and residual tumors (n = 17, 15.4%). Residual tumor after US-guided VAB existed in association with 15.2% of fibroadenomas (7/46), 14.7% of fibrocystic changes (5/34), 13.3% of fibroadenomatoid hyperplasias (2/15), 25% of adenoses (1/4), and 100% of phyllodes tumors (2/2). US-guided VAB is an effective procedure for removal of benign breast lesion. Periodic follow up studies at 1 week and 6 months after the VAB are useful to assess Post-VAB complications

  3. [Mechanistic modelling allows to assess pathways of DNA lesion interactions underlying chromosome aberration formation].

    Science.gov (United States)

    Eĭdel'man, Iu A; Slanina, S V; Sal'nikov, I V; Andreev, S G

    2012-12-01

    The knowledge of radiation-induced chromosomal aberration (CA) mechanisms is required in many fields of radiation genetics, radiation biology, biodosimetry, etc. However, these mechanisms are yet to be quantitatively characterised. One of the reasons is that the relationships between primary lesions of DNA/chromatin/chromosomes and dose-response curves for CA are unknown because the pathways of lesion interactions in an interphase nucleus are currently inaccessible for direct experimental observation. This article aims for the comparative analysis of two principally different scenarios of formation of simple and complex interchromosomal exchange aberrations: by lesion interactions at chromosome territories' surface vs. in the whole space of the nucleus. The analysis was based on quantitative mechanistic modelling of different levels of structures and processes involved in CA formation: chromosome structure in an interphase nucleus, induction, repair and interactions of DNA lesions. It was shown that the restricted diffusion of chromosomal loci, predicted by computational modelling of chromosome organization, results in lesion interactions in the whole space of the nucleus being impossible. At the same time, predicted features of subchromosomal dynamics agrees well with in vivo observations and does not contradict the mechanism of CA formation at the surface of chromosome territories. On the other hand, the "surface mechanism" of CA formation, despite having certain qualities, proved to be insufficient to explain high frequency of complex exchange aberrations observed by mFISH technique. The alternative mechanism, CA formation on nuclear centres is expected to be sufficient to explain frequent complex exchanges.

  4. Trans-Lesion DNA Polymerases May Be Involved in Yeast Meiosis

    Science.gov (United States)

    Arbel-Eden, Ayelet; Joseph-Strauss, Daphna; Masika, Hagit; Printzental, Oxana; Rachi, Eléanor; Simchen, Giora

    2013-01-01

    Trans-lesion DNA polymerases (TLSPs) enable bypass of DNA lesions during replication and are also induced under stress conditions. Being only weakly dependent on their template during replication, TLSPs introduce mutations into DNA. The low processivity of these enzymes ensures that they fall off their template after a few bases are synthesized and are then replaced by the more accurate replicative polymerase. We find that the three TLSPs of budding yeast Saccharomyces cerevisiae Rev1, PolZeta (Rev3 and Rev7), and Rad30 are induced during meiosis at a time when DNA double-strand breaks (DSBs) are formed and homologous chromosomes recombine. Strains deleted for one or any combination of the three TLSPs undergo normal meiosis. However, in the triple-deletion mutant, there is a reduction in both allelic and ectopic recombination. We suggest that trans-lesion polymerases are involved in the processing of meiotic double-strand breaks that lead to mutations. In support of this notion, we report significant yeast two-hybrid (Y2H) associations in meiosis-arrested cells between the TLSPs and DSB proteins Rev1-Spo11, Rev1-Mei4, and Rev7-Rec114, as well as between Rev1 and Rad30. We suggest that the involvement of TLSPs in processing of meiotic DSBs could be responsible for the considerably higher frequency of mutations reported during meiosis compared with that found in mitotically dividing cells, and therefore may contribute to faster evolutionary divergence than previously assumed. PMID:23550131

  5. Analysis of damaged DNA / proteins interactions: Methodological optimizations and applications to DNA lesions induced by platinum anticancer drugs

    International Nuclear Information System (INIS)

    Bounaix Morand du Puch, Ch

    2010-10-01

    DNA lesions contribute to the alteration of DNA structure, thereby inhibiting essential cellular processes. Such alterations may be beneficial for chemotherapies, for example in the case of platinum anticancer agents. They generate bulky adducts that, if not repaired, ultimately cause apoptosis. A better understanding of the biological response to such molecules can be obtained through the study of proteins that directly interact with the damages. These proteins constitute the DNA lesions interactome. This thesis presents the development of tools aiming at increasing the list of platinum adduct-associated proteins. Firstly, we designed a ligand fishing system made of damaged plasmids immobilized onto magnetic beads. Three platinum drugs were selected for our study: cisplatin, oxali-platin and satra-platin. Following exposure of the trap to nuclear extracts from HeLa cancer cells and identification of retained proteins by proteomics, we obtained already known candidates (HMGB1, hUBF, FACT complex) but also 29 new members of the platinated-DNA interactome. Among them, we noted the presence of PNUTS, TOX4 and WDR82, which associate to form the recently-discovered PTW/PP complex. Their capture was then confirmed with a second model, namely breast cancer cell line MDA MB 231, and the biological consequences of such an interaction now need to be elucidated. Secondly, we adapted a SPRi bio-chip to the study of platinum-damaged DNA/proteins interactions. Affinity of HMGB1 and newly characterized TOX4 for adducts generated by our three platinum drugs could be validated thanks to the bio-chip. Finally, we used our tools, as well as analytical chemistry and biochemistry methods, to evaluate the role of DDB2 (a factor involved in the recognition of UV-induced lesions) in the repair of cisplatin adducts. Our experiments using MDA MB 231 cells differentially expressing DDB2 showed that this protein is not responsible for the repair of platinum damages. Instead, it appears to act

  6. Detection and analysis of human papillomavirus 16 and 18 homologous DNA sequences in oral lesions.

    Science.gov (United States)

    Wen, S; Tsuji, T; Li, X; Mizugaki, Y; Hayatsu, Y; Shinozaki, F

    1997-01-01

    The prevalence of human papillomavirus (HPV) 16 and 18 was investigated in oral lesions of the population of northeast China including squamous cell carcinomas (SCCs), candida leukoplakias, lichen planuses and papillomas, by southern blot hybridization with polymerase chain reaction (PCR). Amplified HPV16 and 18 E6 DNA was analyzed by cycle sequence. HPV DNA was detected in 14 of 45 SCCs (31.1%). HPV18 E6 DNA and HPV16 E6. DNA were detected in 24.4% and 20.0% of SCCs. respectively. Dual infection of both HPV 16 and HPV 18 was detected in 6 of 45 SCCs (13.3%), but not in other oral lesions. HPV 18 E6 DNA was also detected in 2 of 3 oral candida leukoplakias, but in none of the 5 papillomas. Our study indicated that HPV 18 infection might be more frequent than HPV 16 infection in oral SCCs in northeast Chinese, dual infection of high risk HPV types was restricted in oral SCCs, and that HPV infection might be involved in the pathogenesis of oral candida leukoplakia.

  7. Base-pairing preferences, physicochemical properties and mutational behaviour of the DNA lesion 8-nitroguanine †

    OpenAIRE

    Bhamra, Inder; Compagnone-Post, Patricia; O’Neil, Ian A.; Iwanejko, Lesley A.; Bates, Andrew D.; Cosstick, Richard

    2012-01-01

    8-Nitro-2′-deoxyguanosine (8-nitrodG) is a relatively unstable, mutagenic lesion of DNA that is increasingly believed to be associated with tissue inflammation. Due to the lability of the glycosidic bond, 8-nitrodG cannot be incorporated into oligodeoxynucleotides (ODNs) by chemical DNA synthesis and thus very little is known about its physicochemical properties and base-pairing preferences. Here we describe the synthesis of 8-nitro-2′-O-methylguanosine, a ribonucleoside analogue of this lesi...

  8. Relationship of DNA lesions and their repair to chromosomal aberration production

    International Nuclear Information System (INIS)

    Bender, M.A.

    1979-01-01

    Recent work on the roles of specific kinds of DNA lesions and their enzymatic repair systems in the production of chromosomal aberrations seems consistent with a simple molecular model of chromosomal aberrations formation. Evidence from experiments with the human repair-deficient genetic diseases xeroderma pigmentosom, ataxia telangiectasia, and Fanconi's anemia is reviewed in the light of the contributions to aberration production of single and double polynucleotide strand breaks, base damage, polynucleotide strand crosslinks, and pyrimidine cyclobutane dimers

  9. Relationship of DNA lesions and their repair to chromosomal aberration production

    Energy Technology Data Exchange (ETDEWEB)

    Bender, M.A.

    1979-01-01

    Recent work on the roles of specific kinds of DNA lesions and their enzymatic repair systems in the production of chromosomal aberrations seems consistent with a simple molecular model of chromosomal aberrations formation. Evidence from experiments with the human repair-deficient genetic diseases xeroderma pigmentosom, ataxia telangiectasia, and Fanconi's anemia is reviewed in the light of the contributions to aberration production of single and double polynucleotide strand breaks, base damage, polynucleotide strand crosslinks, and pyrimidine cyclobutane dimers.

  10. Prevalence of human papillomavirus DNA in female cervical lesions from Rio de Janeiro, Brazil

    Directory of Open Access Journals (Sweden)

    S. M. B. Cavalcanti

    1994-12-01

    Full Text Available A hundred-sixty paraffin-embedded specimens from female cervical lesions were examined for human papillomavirus (HPV types 6, 11, 16 and 18 infections by non-isotopic in situ hybridization. The data were compared with histologic diagnosis. Eighty-eight (55 biopsies contained HPV DNA sequences. In low grade cervical intraepithelial neoplasias (CIN I, HPV infection was detected in 78.7 of the cases, the benign HPV 6 was the most prevalent type. HPV DNA was detected in 58 of CIN II and CIN III cases and in 41.8 of squamous cell carcinomas (SCC. Histologically normal women presented 20 of HPV infection. Oncogenic HPV was found in 10 of these cases, what may indicate a higher risk of developing CINs and cancer. Twenty-five percent of the infected tissues contained mixed infections. HPV 16 was the most common type infecting the cervix and its prevalence raised significantly with the severity of the lesions, pointing its role in cancer pathogenesis. White women presented twice the cervical lesions of mulatto and African origin women, although HPV infection rates were nearly the same for the three groups (approximately 50. Our results showed that HPV typing by in situ hybridization is a useful tool for distinguishing between low and high risk cervical lesions. Further studies are required to elucidate risk factors associated with HPV infection and progression to malignancy in Brazilian population.

  11. Repair of model compounds of photoinduced lesions in DNA. Electrochemical approaches

    International Nuclear Information System (INIS)

    Boussicault, F.

    2006-09-01

    The goal of this work is to better understand the repair mechanism of photoinduced lesions in DNA (cyclobutane dimers and pyrimidine (6-4) pyrimidone adducts) by photolyase redox enzymes, using tools and concepts of molecular electrochemistry. Thanks to the study of model compounds of cyclobutane lesions by cyclic voltametry, we have been able to mimic the key step of the enzymatic repair (dissociative electron transfer) and to monitor the repair of model compounds by Escherichia coli DNA photolyase. From these results, we have discussed the repair mechanism, especially the stepwise or concerted character of the process. Repair mechanism of (6-4) adducts is not known now, but a possible pathway implies an electron transfer coupled to the cleavage of two bonds in the closed form of the lesions (oxetanes). Voltammetric study of reduction and oxidation of model oxetanes and their repair by E. coli DNA photolyase gave some experimental evidence confirming the proposed mechanism and allowing a better understanding of it. (author)

  12. Base-pairing preferences, physicochemical properties and mutational behaviour of the DNA lesion 8-nitroguanine.

    Science.gov (United States)

    Bhamra, Inder; Compagnone-Post, Patricia; O'Neil, Ian A; Iwanejko, Lesley A; Bates, Andrew D; Cosstick, Richard

    2012-11-01

    8-Nitro-2'-deoxyguanosine (8-nitrodG) is a relatively unstable, mutagenic lesion of DNA that is increasingly believed to be associated with tissue inflammation. Due to the lability of the glycosidic bond, 8-nitrodG cannot be incorporated into oligodeoxynucleotides (ODNs) by chemical DNA synthesis and thus very little is known about its physicochemical properties and base-pairing preferences. Here we describe the synthesis of 8-nitro-2'-O-methylguanosine, a ribonucleoside analogue of this lesion, which is sufficiently stable to be incorporated into ODNs. Physicochemical studies demonstrated that 8-nitro-2'-O-methylguanosine adopts a syn conformation about the glycosidic bond; thermal melting studies and molecular modelling suggest a relatively stable syn-8-nitroG·anti-G base pair. Interestingly, when this lesion analogue was placed in a primer-template system, extension of the primer by either avian myeloblastosis virus reverse transcriptase (AMV-RT) or human DNA polymerase β (pol β), was significantly impaired, but where incorporation opposite 8-nitroguanine did occur, pol β showed a 2:1 preference to insert dA over dC, while AMV-RT incorporated predominantly dC. The fact that no 8-nitroG·G base pairing is seen in the primer extension products suggests that the polymerases may discriminate against this pairing system on the basis of its poor geometric match to a Watson-Crick pair.

  13. Base-pairing preferences, physicochemical properties and mutational behaviour of the DNA lesion 8-nitroguanine†

    Science.gov (United States)

    Bhamra, Inder; Compagnone-Post, Patricia; O’Neil, Ian A.; Iwanejko, Lesley A.; Bates, Andrew D.; Cosstick, Richard

    2012-01-01

    8-Nitro-2′-deoxyguanosine (8-nitrodG) is a relatively unstable, mutagenic lesion of DNA that is increasingly believed to be associated with tissue inflammation. Due to the lability of the glycosidic bond, 8-nitrodG cannot be incorporated into oligodeoxynucleotides (ODNs) by chemical DNA synthesis and thus very little is known about its physicochemical properties and base-pairing preferences. Here we describe the synthesis of 8-nitro-2′-O-methylguanosine, a ribonucleoside analogue of this lesion, which is sufficiently stable to be incorporated into ODNs. Physicochemical studies demonstrated that 8-nitro-2′-O-methylguanosine adopts a syn conformation about the glycosidic bond; thermal melting studies and molecular modelling suggest a relatively stable syn-8-nitroG·anti-G base pair. Interestingly, when this lesion analogue was placed in a primer-template system, extension of the primer by either avian myeloblastosis virus reverse transcriptase (AMV-RT) or human DNA polymerase β (pol β), was significantly impaired, but where incorporation opposite 8-nitroguanine did occur, pol β showed a 2:1 preference to insert dA over dC, while AMV-RT incorporated predominantly dC. The fact that no 8-nitroG·G base pairing is seen in the primer extension products suggests that the polymerases may discriminate against this pairing system on the basis of its poor geometric match to a Watson–Crick pair. PMID:22965127

  14. Role of DNA lesions and repair in the transformation of human cells

    International Nuclear Information System (INIS)

    Maher, V.M.; McCormick, J.J.

    1987-01-01

    Results of studies on the transformation of diploid human fibroblasts in culture into tumor-forming cells by exposure to chemical carcinogens or radiation indicate that such transformation is multi-stepped process that at least one step, acquisition of anchorage independence, occurs as a mutagenic event. Studies comparing normal-repairing human cells with DNA repair-deficient cells, such as those derived from cancer-prone xeroderma pigmentosum patients, indicate that excision repair in human fibroblasts is essentially an error-free process that the ability to excise potentially cytotoxic, mutagenic, or transforming lesions induced DNA by carcinogens determines their ultimate biological consequences. Cells deficient in excision repair are abnormally sensitive to these agents. Studies with cells treated at various times in the cell cycle show that there is a certain limited amount of time available for DNA repair between the initial exposure and the onset of the cellular event responsible for mutation induction and transformation to anchorage independence. The data suggest that DNA replication on a template containing unexcised lesions (photoproducts, adducts) is the critical event

  15. Statistical analysis of post mortem DNA damage-derived miscoding lesions in Neandertal mitochondrial DNA

    DEFF Research Database (Denmark)

    Vives, Sergi; Gilbert, M Thomas; Arenas, Conchita

    2008-01-01

    in the Heavy strand could explain the observed bias, a phenomenon that could be further tested with non-PCR based approaches. The characterization of the HVS1 hotspots will be of use to future Neandertal mtDNA studies, with specific regards to assessing the authenticity of new positions previously unknown...

  16. Distribution of ultraviolet-induced lesions in Simian Virus 40 DNA

    International Nuclear Information System (INIS)

    Bourre, F.; Renault, G.; Sarasin, A.; Seawell, P.C.

    1985-01-01

    In order to analyze the molecular mechanisms of mutagenesis in mammalian cells, we devised an analytical assay using Simian Virus 40 as biological probe. To study the possible correlations between the distribution of the lesions on the treated DNA and the distribution of mutations, we have located and quantified the lesions induced by ultraviolet light (254 nm) on a SV40 DNA fragment. At a fluence of 2,000J/m 2 , our results show that the formation frequency of thymine-thymine dimers (TT) is three to four times higher than the formation frequency of the other types of dimers (TC, CT, CC). On the other hand, the formation frequency of a dimer is influenced by the adjacent sequence. In particular, a pyrimidine in the 5' position of a thymine-thymine dimer enhances its formation frequency. At the dose used the formation frequency of the pyrimidine (6-4) pyrimidone photoproducts is twenty times less than the formation frequency of pyrimidine dimers. This paper shows the distribution of the major lesions induced by UV-light on a defined fragment of SV40 genome after UV irradiation. This work is necessary to get an insight in the molecular mechanisms of UV-mutagenesis

  17. Effects of radiation quality and oxygen on clustered DNA lesions and cell death.

    Science.gov (United States)

    Stewart, Robert D; Yu, Victor K; Georgakilas, Alexandros G; Koumenis, Constantinos; Park, Joo Han; Carlson, David J

    2011-11-01

    Radiation quality and cellular oxygen concentration have a substantial impact on DNA damage, reproductive cell death and, ultimately, the potential efficacy of radiation therapy for the treatment of cancer. To better understand and quantify the effects of radiation quality and oxygen on the induction of clustered DNA lesions, we have now extended the Monte Carlo Damage Simulation (MCDS) to account for reductions in the initial lesion yield arising from enhanced chemical repair of DNA radicals under hypoxic conditions. The kinetic energy range and types of particles considered in the MCDS have also been expanded to include charged particles up to and including (56)Fe ions. The induction of individual and clustered DNA lesions for arbitrary mixtures of different types of radiation can now be directly simulated. For low-linear energy transfer (LET) radiations, cells irradiated under normoxic conditions sustain about 2.9 times as many double-strand breaks (DSBs) as cells irradiated under anoxic conditions. New experiments performed by us demonstrate similar trends in the yields of non-DSB (Fpg and Endo III) clusters in HeLa cells irradiated by γ rays under aerobic and hypoxic conditions. The good agreement among measured and predicted DSBs, Fpg and Endo III cluster yields suggests that, for the first time, it may be possible to determine nucleotide-level maps of the multitude of different types of clustered DNA lesions formed in cells under reduced oxygen conditions. As particle LET increases, the MCDS predicts that the ratio of DSBs formed under normoxic to hypoxic conditions by the same type of radiation decreases monotonically toward unity. However, the relative biological effectiveness (RBE) of higher-LET radiations compared to (60)Co γ rays (0.24 keV/μm) tends to increase with decreasing oxygen concentration. The predicted RBE of a 1 MeV proton (26.9 keV/μm) relative to (60)Co γ rays for DSB induction increases from 1.9 to 2.3 as oxygen concentration

  18. In vitro enzymatic studies on the nature and repair of x-ray induced lesions in DNA

    International Nuclear Information System (INIS)

    Wallace, S.S.

    1979-01-01

    Areas studied include: purification and properties of enzyme probes for x-ray induced DNA lesions using E. Coli x-ray endonuclease and S. cerevisiae endonuclease E; use of enzymes probes; and use of physical, chemical and enzymatic probes to quantify x-ray-induced lesions in viruses and cells

  19. Standard guidelines of care: CO2 laser for removal of benign skin lesions and resurfacing.

    Science.gov (United States)

    Krupashankar, D S

    2008-01-01

    Resurfacing is a treatment to remove acne and chicken pox scars, and changes in the skin due to ageing. MACHINES: Both ablative and nonablative lasers are available for use. CO 2 laser is the gold standard in ablative lasers. Detailed knowledge of the machines is essential. INDICATIONS FOR CO 2 LASER: Therapeutic indications: Actinic and seborrheic keratosis, warts, moles, skin tags, epidermal and dermal nevi, vitiligo blister and punch grafting, rhinophyma, sebaceous hyperplasia, xanthelasma, syringomas, actinic cheilitis angiofibroma, scar treatment, keloid, skin cancer, neurofibroma and diffuse actinic keratoses. CO 2 laser is not recommended for the removal of tattoos. AESTHETIC INDICATIONS: Resurfacing for acne, chicken pox and surgical scars, periorbital and perioral wrinkles, photo ageing changes, facial resurfacing. PHYSICIANS' QUALIFICATIONS: Any qualified dermatologist (DVD or MD) may practice CO 2 laser. The dermatologist should possess postgraduate qualification in dermatology and should have had specific hands-on training in lasers either during postgraduation or later at a facility which routinely performs laser procedures under a competent dermatologist/plastic surgeon, who has experience and training in using lasers. For the use of CO 2 lasers for benign growths, a full day workshop is adequate. As parameters may vary in different machines, specific training with the available machine at either the manufacturer's facility or at another centre using the machine is recommended. CO 2 lasers can be used in the dermatologist's minor procedure room for the above indications. However, when used for full-face resurfacing, the hospital operation theatre or day care facility with immediate access to emergency medical care is essential. Smoke evacuator is mandatory. Detailed counseling with respect to the treatment, desired effects, possible postoperative complications, should be discussed with the patient. The patient should be provided brochures to study and

  20. Standard guidelines of care: CO 2 laser for removal of benign skin lesions and resurfacing

    Directory of Open Access Journals (Sweden)

    Krupashankar D

    2008-03-01

    Full Text Available Resurfacing is a treatment to remove acne and chicken pox scars, and changes in the skin due to ageing. Machines : Both ablative and nonablative lasers are available for use. CO 2 laser is the gold standard in ablative lasers. Detailed knowledge of the machines is essential. Indications for CO 2 laser: Therapeutic indications: Actinic and seborrheic keratosis, warts, moles, skin tags, epidermal and dermal nevi, vitiligo blister and punch grafting, rhinophyma, sebaceous hyperplasia, xanthelasma, syringomas, actinic cheilitis angiofibroma, scar treatment, keloid, skin cancer, neurofibroma and diffuse actinic keratoses. CO 2 laser is not recommended for the removal of tattoos. Aesthetic indications: Resurfacing for acne, chicken pox and surgical scars, periorbital and perioral wrinkles, photo ageing changes, facial resurfacing. Physicians′ qualifications: Any qualified dermatologist (DVD or MD may practice CO 2 laser. The dermatologist should possess postgraduate qualification in dermatology and should have had specific hands-on training in lasers either during postgraduation or later at a facility which routinely performs laser procedures under a competent dermatologist/plastic surgeon, who has experience and training in using lasers. For the use of CO 2 lasers for benign growths, a full day workshop is adequate. As parameters may vary in different machines, specific training with the available machine at either the manufacturer′s facility or at another centre using the machine is recommended. Facility: CO 2 lasers can be used in the dermatologist′s minor procedure room for the above indications. However, when used for full-face resurfacing, the hospital operation theatre or day care facility with immediate access to emergency medical care is essential. Smoke evacuator is mandatory. Preoperative counseling and Informed consent Detailed counseling with respect to the treatment, desired effects, possible postoperative complications, should be

  1. Atherosclerotic lesions and mitochondria DNA deletions in brain microvessels: implication in the pathogenesis of Alzheimer's disease.

    Science.gov (United States)

    Aliev, Gjumrakch; Gasimov, Eldar; Obrenovich, Mark E; Fischbach, Kathryn; Shenk, Justin C; Smith, Mark A; Perry, George

    2008-01-01

    The pathogenesis that is primarily responsible for Alzheimer's disease (AD) and cerebrovascular accidents (CVA) appears to involve chronic hypoperfusion. We studied the ultrastructural features of vascular lesions and mitochondria in brain vascular wall cells from human AD biopsy samples and two transgenic mouse models of AD, yeast artificial chromosome (YAC) and C57B6/SJL Tg (+), which overexpress human amyloid beta precursor protein (AbetaPP). In situ hybridization using probes for normal and 5 kb deleted human and mouse mitochondrial DNA (mtDNA) was performed along with immunocytochemistry using antibodies against the Abeta peptide processed from AbetaPP, 8-hydroxy-2'-guanosine (8OHG), and cytochrome c oxidase (COX). More amyloid deposition, oxidative stress markers as well as mitochondrial DNA deletions and structural abnormalities were present in the vascular walls of the human AD samples and the AbetaPP-YAC and C57B6/SJL Tg (+) transgenic mice compared to age-matched controls. Ultrastructural damage in perivascular cells highly correlated with endothelial lesions in all samples. Therefore, pharmacological interventions, directed at correcting the chronic hypoperfusion state, may change the natural course of the development of dementing neurodegeneration.

  2. The DNA Repair Repertoire of Mycobacterium smegmatis FenA Includes the Incision of DNA 5' Flaps and the Removal of 5' Adenylylated Products of Aborted Nick Ligation.

    Science.gov (United States)

    Uson, Maria Loressa; Ghosh, Shreya; Shuman, Stewart

    2017-09-01

    We characterize Mycobacterium smegmatis FenA as a manganese-dependent 5'-flap endonuclease homologous to the 5'-exonuclease of DNA polymerase I. FenA incises a nicked 5' flap between the first and second nucleotides of the duplex segment to yield a 1-nucleotide gapped DNA, which is then further resected in dinucleotide steps. Initial FenA cleavage at a Y-flap or nick occurs between the first and second nucleotides of the duplex. However, when the template 3' single strand is eliminated to create a 5'-tailed duplex, FenA incision shifts to between the second and third nucleotides. A double-flap substrate with a mobile junction (mimicking limited strand displacement synthesis during gap repair) is preferentially incised as the 1-nucleotide 3'-flap isomer, with the scissile phosphodiester shifted by one nucleotide versus a static double flap. FenA efficiently removes the 5' App(dN) terminus of an aborted nick ligation reaction intermediate, thereby highlighting FenA as an agent of repair of such lesions, which are formed under a variety of circumstances by bacterial NAD + -dependent DNA ligases and especially by mycobacterial DNA ligases D and C. IMPORTANCE Structure-specific DNA endonucleases are implicated in bacterial DNA replication, repair, and recombination, yet there is scant knowledge of the roster and catalytic repertoire of such nucleases in Mycobacteria This study identifies M. smegmatis FenA as a stand-alone endonuclease homologous to the 5'-exonuclease domain of mycobacterial DNA polymerase 1. FenA incises 5' flaps, 5' nicks, and 5' App(dN) intermediates of aborted nick ligation. The isolated N-terminal domain of M. smegmatis Pol1 is also shown to be a flap endonuclease. Copyright © 2017 American Society for Microbiology.

  3. Radio-guided occult lesion localisation using iodine-125 seeds ('ROLLIS') for removal of impalpable breast lesions: first Australian experience

    International Nuclear Information System (INIS)

    Taylor, Donna B.; Bourke, Anita G.; Westcott, Eliza

    2015-01-01

    Approximately one-third of breast cancers are impalpable and require pre-operative image-guided localisation. Hook-wire localisation (HWL) is commonly used but has several disadvantages. Use of a low-activity radioactive iodine-125 seed is a promising alternative technique used in the USA and the Netherlands. This pilot study describes the first use of this in Australia. In this prospective pilot study, 21 participants with biopsy-proven breast cancer underwent radio guided occult lesion localisation using iodine-125 seed(s) (ROLLIS) with insertion of a hook-wire for back up. Sentinel node biopsy was performed where indicated. Ease of hook-wire and seed insertion, duration of the procedure, dependence on the seed versus hook-wire during surgery, lesion location within the specimen, histopathology including size of radial margins, the ease of seed retrieval in pathology, and safe return of seeds for disposal were documented. Radiation dosimetry of staff was performed. All seeds were placed within 3.5 mm of the lesion. All lesions and seeds were removed. One participant needed re-excision for involved margins. Radiologists and surgeons both preferred ROLLIS. Surgeons were able to depend on the seed for localisation in all but one case. Sentinel node biopsy was successfully performed when required. Pathologists found seed retrieval quick and easy, with no detrimental effect on tissue processing. No radiation doses measurably above background were received by staff. ROLLIS is an easily learnt, safe and effective alternative technique to standard HWL.

  4. Repair of UVC induced DNA lesions in erythrocytes from Carassius auratus gibelio

    International Nuclear Information System (INIS)

    Bagdonas, E.; Zukas, K.

    2004-01-01

    The kinetics of UVC (254 nm) irradiation induced DNA single-strand breaks generated during the excision repair of UV induced DNA damage in erythrocytes from Carassius auratus gibelio were studied using alkaline comet assay. Nucleotide excision repair recognised DNA lesions such as UVC induced cyclobutane pyrimidine dimers and 6-4 pyrimidine-pyrimidone photoproducts and produced DNA single-stranded breaks that were easily detected by comet assay. After irradiation of erythrocytes with 58 j/m 2 UVC dose, there was an increase in comet tail moment (CTM) at 2 hours post-radiation, whereas at 4 hours post-radiation CTM decreased and did not differ significantly from the control level (P=0,127). When erythrocytes were exposed to 173 J/m 2 UVC dose, the excision repair delayed in the beginning (0 hours), reached maximum level at 2 hours post-radiation (CTM-54,8) and showed slightly decreased level at 4 hours post-radiation (CTM=18,5). (author)

  5. Permanganate-assisted removal of PCR inhibitors during the DNA Chelex extraction from stained denim samples.

    Science.gov (United States)

    Pîrlea, Sorina; Puiu, Mihaela; Răducan, Adina; Oancea, Dumitru

    2017-03-01

    In this study, it was demonstrated that the DNA Chelex extraction combined with the permanganate assisted-oxidation is highly efficient in removing the PCR inhibitors often found in clothing materials, such as phthalocyanine. The extraction assays were conducted in saliva, blood and epithelial cells samples mixed with three oxidation-resistant dye copper(II) α-phthalocyanine, copper(II) β-phthalocyanine and tetrasulfonated copper(II) β-phthalocyanine. After DNA amplification, all samples were able to provide full DNA profiles. The permanganate/Chelex system was tested further on denim-stained samples and displayed the same ability to remove the PCR inhibitors from the commercial textile materials.

  6. Chemistry of the 8-Nitroguanine DNA Lesion: Reactivity, Labelling and Repair.

    Science.gov (United States)

    Alexander, Katie J; McConville, Matthew; Williams, Kathryn R; Luzyanin, Konstantin V; O'Neil, Ian A; Cosstick, Richard

    2018-02-26

    The 8-nitroguanine lesion in DNA is increasingly associated with inflammation-related carcinogenesis, whereas the same modification on guanosine 3',5'-cyclic monophosphate generates a second messenger in NO-mediated signal transduction. Very little is known about the chemistry of 8-nitroguanine nucleotides, despite the fact that their biological effects are closely linked to their chemical properties. To this end, a selection of chemical reactions have been performed on 8-nitroguanine nucleosides and oligodeoxynucleotides. Reactions with alkylating reagents reveal how the 8-nitro substituent affects the reactivity of the purine ring, by significantly decreasing the reactivity of the N2 position, whilst the relative reactivity at N1 appears to be enhanced. Interestingly, the displacement of the nitro group with thiols results in an efficient and specific method of labelling this lesion and is demonstrated in oligodeoxynucleotides. Additionally, the repair of this lesion is also shown to be a chemically feasible reaction through a reductive denitration with a hydride source. © 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  7. The influence of inhibitors on dimer removal and repair of single-strand breaks in normal and bromodeoxyuridine substituted DNA of HeLa cells

    International Nuclear Information System (INIS)

    Cornelis, J.J.

    1978-01-01

    The elimination of cyclobutane pyrimidine dimers from the nuclear DNA of ultraviolet irradiated HeLa cells has been examined by means of chromatography and immunoautoradiography. The extent and duration of the process was similar when dimers were assayed by both methods, proving that the antisera recognized pyrimidine dimers. The rate of dimer excision did not differ through the cell cycle with the exception of mitosis during which no dimers were removed. Dimer excision is a relatively fast process which is terminated within a few hours, but it leaves many dimers in the DNA. Excision is depressed by inhibitors of semiconservative DNA synthesis that affect the DNA precursor pool or DNA polymerases. Cells whose DNA is partly substituted with bromodeoxyuridine instead of thymidine, repair single-strand breaks and remove dimers at the same rate but to different extents. On the other hand, inhibitors limit repair of breaks and removal of dimers to the same degree suggesting that the repair of the two types of lesion is coordinated. (Auth.)

  8. Carboxymethyl chitin-glucan (CM-CG) protects human HepG2 and HeLa cells against oxidative DNA lesions and stimulates DNA repair of lesions induced by alkylating agents.

    Science.gov (United States)

    Slamenová, Darina; Kováciková, Ines; Horváthová, Eva; Wsólová, Ladislava; Navarová, Jana

    2010-10-01

    A large number of functional foods, including those that contain β-d-glucans, have been shown to prevent human DNA against genotoxic effects and associated development of cancer and other chronic diseases. In this paper, carboxymethyl chitin-glucan (CM-CG) isolated from Aspergillus niger was investigated from two standpoints: (1) DNA-protective effects against oxidative DNA damage induced by H(2)O(2) and alkylating DNA damage induced by MMS and MNNG, and (2) a potential effect on rejoining of MMS- and MNNG-induced single strand DNA breaks. The results obtained by the comet assay in human cells cultured in vitro showed that CM-CG reduced significantly the level of oxidative DNA lesions induced by H(2)O(2) but did not change the level of alkylating DNA lesions induced by MMS or MNNG. On the other side, the efficiency of DNA-rejoining of single strand DNA breaks induced by MMS and MNNG was significantly higher in HepG2 cells pre-treated with CM-CG. The antioxidative activity of carboxymethyl chitin-glucan was confirmed by the DPPH assay. Copyright © 2010 Elsevier Ltd. All rights reserved.

  9. Towards observing the encounter of the T7 DNA replication fork with a lesion site at the Single molecule level

    KAUST Repository

    Shirbini, Afnan

    2017-01-01

    and established the T7 leading strand synthesis at the single molecule level. I also optimized various control experiments to remove any interference from the nonspecific interactions of the DNA with the surface. My work established the foundation to image

  10. DNA alkylation lesions and their repair in human cells: modification of the comet assay with 3-methyladenine DNA glycosylase (AlkD).

    Science.gov (United States)

    Hašplová, Katarína; Hudecová, Alexandra; Magdolénová, Zuzana; Bjøras, Magnar; Gálová, Eliška; Miadoková, Eva; Dušinská, Mária

    2012-01-05

    3-methyladenine DNA glycosylase (AlkD) belongs to a new family of DNA glycosylases; it initiates repair of cytotoxic and promutagenic alkylated bases (its main substrates being 3-methyladenine and 7-methylguanine). The modification of the comet assay (single cell gel electrophoresis) using AlkD enzyme thus allows assessment of specific DNA alkylation lesions. The resulting baseless sugars are alkali-labile, and under the conditions of the alkaline comet assay they appear as DNA strand breaks. The alkylating agent methyl methanesulfonate (MMS) was used to induce alkylation lesions and to optimize conditions for the modified comet assay method with AlkD on human lymphoblastoid (TK6) cells. We also studied cellular and in vitro DNA repair of alkylated bases in DNA in TK6 cells after treatment with MMS. Results from cellular repair indicate that 50% of DNA alkylation is repaired in the first 60 min. The in vitro repair assay shows that while AlkD recognises most alkylation lesions after 60 min, a cell extract from TK6 cells recognises most of the MMS-induced DNA adducts already in the first 15 min of incubation, with maximum detection of lesions after 60 min' incubation. Additionally, we tested the in vitro repair capacity of human lymphocyte extracts from 5 individuals and found them to be able to incise DNA alkylations in the same range as AlkD. The modification of the comet assay with AlkD can be useful for in vitro and in vivo genotoxicity studies to detect alkylation damage and repair and also for human biomonitoring and molecular epidemiology studies. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  11. Mitochondrial DNA mutations in preneoplastic lesions of the gastrointestinal tract: A biomarker for the early detection of cancer

    Directory of Open Access Journals (Sweden)

    Montgomery Elizabeth A

    2006-12-01

    Full Text Available Abstract Background Somatic mutations of mitochondrial DNA (mtDNA are common in many human cancers. We have described an oligonucleotide microarray ("MitoChip" for rapid sequencing of the entire mitochondrial genome (Zhou et al, J Mol Diagn 2006, facilitating the analysis of mtDNA mutations in preneoplastic lesions. We examined 14 precancerous lesions, including seven Barrett esophagus biopsies, with or without associated dysplasia; four colorectal adenomas; and three inflammatory colitis-associated dysplasia specimens. In all cases, matched normal tissues from the corresponding site were obtained as germline control. MitoChip analysis was performed on DNA obtained from cryostat-embedded specimens. Results A total of 513,639 bases of mtDNA were sequenced in the 14 samples, with 490,224 bases (95.4% bases assigned by the automated genotyping software. All preneoplastic lesions examined demonstrated at least one somatic mtDNA sequence alteration. Of the 100 somatic mtDNA alterations observed in the 14 cases, 27 were non-synonymous coding region mutations (i.e., resulting in an amino acid change, 36 were synonymous, and 37 involved non-coding mtDNA. Overall, somatic alterations most commonly involved the COI, ND4 and ND5 genes. Notably, somatic mtDNA alterations were observed in preneoplastic lesions of the gastrointestinal tract even in the absence of histopathologic evidence of dysplasia, suggesting that the mitochondrial genome is susceptible at the earliest stages of multistep cancer progression. Conclusion Our findings further substantiate the rationale for exploring the mitochondrial genome as a biomarker for the early diagnosis of cancer, and confirm the utility of a high-throughput array-based platform for this purpose from a clinical applicability standpoint.

  12. Lethal and mutagenic properties of MMS-generated DNA lesions in Escherichia coli cells deficient in BER and AlkB-directed DNA repair.

    Science.gov (United States)

    Sikora, Anna; Mielecki, Damian; Chojnacka, Aleksandra; Nieminuszczy, Jadwiga; Wrzesinski, Michal; Grzesiuk, Elzbieta

    2010-03-01

    Methylmethane sulphonate (MMS), an S(N)2-type alkylating agent, generates DNA methylated bases exhibiting cytotoxic and mutagenic properties. Such damaged bases can be removed by a system of base excision repair (BER) and by oxidative DNA demethylation catalysed by AlkB protein. Here, we have shown that the lack of the BER system and functional AlkB dioxygenase results in (i) increased sensitivity to MMS, (ii) elevated level of spontaneous and MMS-induced mutations (measured by argE3 --> Arg(+) reversion) and (iii) induction of the SOS response shown by visualization of filamentous growth of bacteria. In the xth nth nfo strain additionally mutated in alkB gene, all these effects were extreme and led to 'error catastrophe', resulting from the presence of unrepaired apurinic/apyrimidinic (AP) sites and 1-methyladenine (1meA)/3-methylcytosine (3meC) lesions caused by deficiency in, respectively, BER and AlkB dioxygenase. The decreased level of MMS-induced Arg(+) revertants in the strains deficient in polymerase V (PolV) (bearing the deletion of the umuDC operon), and the increased frequency of these revertants in bacteria overproducing PolV (harbouring the pRW134 plasmid) indicate the involvement of PolV in the error-prone repair of 1meA/3meC and AP sites. Comparison of the sensitivity to MMS and the induction of Arg(+) revertants in the double nfo alkB and xth alkB, and the quadruple xth nth nfo alkB mutants showed that the more AP sites there are in DNA, the stronger the effect of the lack of AlkB protein. Since the sum of MMS-induced Arg(+) revertants in xth, nfo and nth xth nfo and alkB mutants is smaller than the frequency of these revertants in the BER(-) alkB(-) strain, we consider two possibilities: (i) the presence of AP sites in DNA results in relaxation of its structure that facilitates methylation and (ii) additional AP sites are formed in the BER(-) alkB(-) mutants.

  13. Repair of model compounds of photoinduced lesions in DNA. Electrochemical approaches; Reparation de modeles de lesions photoinduites de l'ADN. Approches electrochimiques

    Energy Technology Data Exchange (ETDEWEB)

    Boussicault, F

    2006-09-15

    The goal of this work is to better understand the repair mechanism of photoinduced lesions in DNA (cyclobutane dimers and pyrimidine (6-4) pyrimidone adducts) by photolyase redox enzymes, using tools and concepts of molecular electrochemistry. Thanks to the study of model compounds of cyclobutane lesions by cyclic voltametry, we have been able to mimic the key step of the enzymatic repair (dissociative electron transfer) and to monitor the repair of model compounds by Escherichia coli DNA photolyase. From these results, we have discussed the repair mechanism, especially the stepwise or concerted character of the process. Repair mechanism of (6-4) adducts is not known now, but a possible pathway implies an electron transfer coupled to the cleavage of two bonds in the closed form of the lesions (oxetanes). Voltammetric study of reduction and oxidation of model oxetanes and their repair by E. coli DNA photolyase gave some experimental evidence confirming the proposed mechanism and allowing a better understanding of it. (author)

  14. Does trans-lesion synthesis explain the UV-radiation resistance of DNA synthesis in C.elegans embryos?

    International Nuclear Information System (INIS)

    Hartman, Phil; Reddy, Jennifer; Svendsen, Betty-Ann

    1991-01-01

    Over 10-fold larger fluences were required to inhibit both DNA synthesis and cell division in wild-type C.elegans embryos as compared with other model systems or C.elegans rad mutants. In addition, unlike in other organisms, the molecular weight of daughter DNA strands was reduced only after large, superlethal fluences. The molecular weight of nascent DNA fragments exceeded the interdimer distance by up to 19-fold, indicating that C.elegans embryos can replicate through non-instructional lesions. This putative trans-lesion synthetic capability may explain the refractory nature of UV-radiation on embryonic DNA synthesis and nuclear division in C.elegans. (author). 42 refs.; 7 figs

  15. Does trans-lesion synthesis explain the UV-radiation resistance of DNA synthesis in C. elegans embryos

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, Phil; Reddy, Jennifer; Svendsen, Betty-Ann [Texas Christian Univ., Fort Worth, TX (United States). Dept. of Biology

    1991-09-01

    Over 10-fold larger fluences were required to inhibit both DNA synthesis and cell division in wild-type C.elegans embryos as compared with other model systems or C.elegans rad mutants. In addition, unlike in other organisms, the molecular weight of daughter DNA strands was reduced only after large, superlethal fluences. The molecular weight of nascent DNA fragments exceeded the interdimer distance by up to 19-fold, indicating that C.elegans embryos can replicate through non-instructional lesions. This putative trans-lesion synthetic capability may explain the refractory nature of UV-radiation on embryonic DNA synthesis and nuclear division in C.elegans. (author). 42 refs.; 7 figs.

  16. Evaluation of patients with oral lichenoid lesions by dental patch testing and results of removal of the dental restoration material

    Directory of Open Access Journals (Sweden)

    Emine Buket Şahin

    2016-12-01

    Full Text Available Background and Design: Oral lichenoid lesions (OLL are contact stomatitis characterized by white reticular or erosive patches, plaque-like lesions that are clinically and histopathologically indistinguishable from oral lichen planus (OLP. Amalgam dental fillings and dental restoration materials are among the etiologic agents. In the present study, it was aimed to evaluate the standard and dental series patch tests in patients with OLL in comparison to a control group and evaluate our results. Materials and Methods: Thirty-three patients with OLL or OLP and 30 healthy control subjects, who had at least one dental restoration material and/or dental filling, were included in the study. Both groups received standard series and dental patch test and the results were evaluated simultaneously. Results: The most frequent allergens in the dental series patch test in the patient group were palladium chloride (n=4; 12.12% and benzoyl peroxide (n=2, 6.06%. Of the 33 patients with OLL; 8 had positive reaction to allergents in the standard patch test series and 8 had positive reaction in the dental patch test series. There was no significant difference in the rate of patch test reaction to the dental and standard series between the groups. Ten patients were advised to have the dental restoration material removed according to the results of the patch tests. The lesions improved in three patients [removal of all amalgam dental fillings (n=1, replacement of all amalgam dental fillings with an alternative filling material (n=1 and replacement of the dental prosthesis (n=1] following the removal or replacement of the dental restoration material. Conclusion: Dental patch test should be performed in patients with OLL and dental restoration material. Dental filling and/or prosthesis should be removed/replaced if there is a reaction against a dental restoration material-related allergen.

  17. Use of avidin-biotin-peroxidase complex for measurement of UV lesions in human DNA by microELISA

    Energy Technology Data Exchange (ETDEWEB)

    Leipold, B [Technischen Universitaet Muenchen (Germany, F.R.). Dermatologische Klinik; Remy, W [Max-Planck-Institut fuer Biochemie, Muenchen (Germany, F.R.)

    1984-02-10

    The avidin/biotin system was introduced into the standard enzyme-linked immunosorbent assay (ELISA) to increase its sensitivity for detecting UV lesions in human DNA. Goat anti-rabbit IgG-peroxidase used in the standard ELISA as second antibody was replaced by biotinylated goat anti-rabbit IgG plus the avidin-biotin-peroxidase complex (ABC) reagent. Sensitivity of detection of plate-fixed UV-DNA-antibody complexes was increased about 8-fold and photolesions in human DNA samples irradiated with as low a dose as 1 J/m/sup 2/ UVC or a suberythermal dose of UVB light could be detected.

  18. XRCC1 and PCNA are loading platforms with distinct kinetic properties and different capacities to respond to multiple DNA lesions

    Directory of Open Access Journals (Sweden)

    Leonhardt Heinrich

    2007-09-01

    Full Text Available Abstract Background Genome integrity is constantly challenged and requires the coordinated recruitment of multiple enzyme activities to ensure efficient repair of DNA lesions. We investigated the dynamics of XRCC1 and PCNA that act as molecular loading platforms and play a central role in this coordination. Results Local DNA damage was introduced by laser microirradation and the recruitment of fluorescent XRCC1 and PCNA fusion proteins was monitored by live cell microscopy. We found an immediate and fast recruitment of XRCC1 preceding the slow and continuous recruitment of PCNA. Fluorescence bleaching experiments (FRAP and FLIP revealed a stable association of PCNA with DNA repair sites, contrasting the high turnover of XRCC1. When cells were repeatedly challenged with multiple DNA lesions we observed a gradual depletion of the nuclear pool of PCNA, while XRCC1 dynamically redistributed even to lesions inflicted last. Conclusion These results show that PCNA and XRCC1 have distinct kinetic properties with functional consequences for their capacity to respond to successive DNA damage events.

  19. XRCC1 and PCNA are loading platforms with distinct kinetic properties and different capacities to respond to multiple DNA lesions

    Science.gov (United States)

    Mortusewicz, Oliver; Leonhardt, Heinrich

    2007-01-01

    Background Genome integrity is constantly challenged and requires the coordinated recruitment of multiple enzyme activities to ensure efficient repair of DNA lesions. We investigated the dynamics of XRCC1 and PCNA that act as molecular loading platforms and play a central role in this coordination. Results Local DNA damage was introduced by laser microirradation and the recruitment of fluorescent XRCC1 and PCNA fusion proteins was monitored by live cell microscopy. We found an immediate and fast recruitment of XRCC1 preceding the slow and continuous recruitment of PCNA. Fluorescence bleaching experiments (FRAP and FLIP) revealed a stable association of PCNA with DNA repair sites, contrasting the high turnover of XRCC1. When cells were repeatedly challenged with multiple DNA lesions we observed a gradual depletion of the nuclear pool of PCNA, while XRCC1 dynamically redistributed even to lesions inflicted last. Conclusion These results show that PCNA and XRCC1 have distinct kinetic properties with functional consequences for their capacity to respond to successive DNA damage events. PMID:17880707

  20. DNA damage signaling and apoptosis in preinvasive tubal lesions of ovarian carcinoma.

    Science.gov (United States)

    Chene, Gautier; Ouellet, Veronique; Rahimi, Kurosh; Barres, Veronique; Caceres, Katia; Meunier, Liliane; Cyr, Louis; De Ladurantaye, Manon; Provencher, Diane; Mes Masson, Anne Marie

    2015-06-01

    High-grade serous ovarian cancer (HGSC) is the most life-threatening gynecological malignancy despite surgery and chemotherapy. A better understanding of the molecular basis of the preinvasive stages might be helpful in early detection and diagnosis. Genetic instability is 1 of the characteristics shared by most human cancers, and its level is variable through precancerous lesions to advanced cancer. Because DNA damage response (DDR) has been described as 1 of the first phases in genomic instability, we investigated the level of DDR activation and the apoptosis pathway in serous tubal intraepithelial carcinoma (STIC), the potential precursor of HGSC. A tissue microarray including 21 benign fallopian tubes, 21 STICs, 17 HGSCs from patients with STICs (associated ovarian cancer [AOC]) from the same individuals, and 30 HGSCs without STICs (non-AOC) was used in this study.Immunohistochemistry was performed to evaluate the level of DDR proteins (pATM, pChk2, γH2AX, 53BP1, and TRF2), apoptosis proteins (Bcl2, BAX, and BIM), and cyclin E. The expression of all DDR proteins increased from benign fallopian tubes to STICs. The level of expression of pATM, pChk2, γH2AX, and TRF2 was also increased in STICs in comparison with AOC. BAX, BIM, and cyclin E expressions were high in STICs, whereas Bcl2 expression was low. Immunohistochemical profiles of AOC and non-AOC were also different. These results suggest an activation of the DDR and apoptosis pathways in STICs, indicating that genomic instability may occur early in the precancerous lesions of HGSC.

  1. 53BP1 nuclear bodies form around DNA lesions generated by mitotic transmission of chromosomes under replication stress

    DEFF Research Database (Denmark)

    Lukas, Claudia; Savic, Velibor; Bekker-Jensen, Simon

    2011-01-01

    stress increases the frequency of chromosomal lesions that are transmitted to daughter cells. Throughout G1, these lesions are sequestered in nuclear compartments marked by p53-binding protein 1 (53BP1) and other chromatin-associated genome caretakers. We show that the number of such 53BP1 nuclear bodies...... increases after genetic ablation of BLM, a DNA helicase associated with dissolution of entangled DNA. Conversely, 53BP1 nuclear bodies are partially suppressed by knocking down SMC2, a condensin subunit required for mechanical stability of mitotic chromosomes. Finally, we provide evidence that 53BP1 nuclear...... bodies shield chromosomal fragile sites sequestered in these compartments against erosion. Together, these data indicate that restoration of DNA or chromatin integrity at loci prone to replication problems requires mitotic transmission to the next cell generations....

  2. Learning tasks as a possible treatment for DNA lesions induced by oxidative stress in hippocampal neurons

    Institute of Scientific and Technical Information of China (English)

    DragoCrneci; Radu Silaghi-Dumitrescu

    2013-01-01

    Reactive oxygen species have been implicated in conditions ranging from cardiovascular dysfunc-tion, arthritis, cancer, to aging and age-related disorders. The organism developed several path-ways to counteract these effects, with base excision repair being responsible for repairing one of the major base lesions (8-oxoG) in al organisms. Epidemiological evidence suggests that cognitive stimulation makes the brain more resilient to damage or degeneration. Recent studies have linked enriched environment to reduction of oxidative stressin neurons of mice with Alzheimer’s dis-ease-like disease, but given its complexity it is not clear what specific aspect of enriched environ-ment has therapeutic effects. Studies from molecular biology have shown that the protein p300, which is a transcription co-activator required for consolidation of memories during specific learning tasks, is at the same time involved in DNA replication and repair, playing a central role in the long-patch pathway of base excision repair. Based on the evidence, we propose that learning tasks such as novel object recognition could be tested as possible methods of base excision repair faci-litation, hence inducing DNA repair in the hippocampal neurons. If this method proves to be effective, it could be the start for designing similar tasks for humans, as a behavioral therapeutic complement to the classical drug-based therapy in treating neurodegenerative disorders. This review presents the current status of therapeutic methods used in treating neurodegenerative diseases induced by reactive oxygen species and proposes a new approach based on existing data.

  3. DNA Methylation of MMP9 Is Associated with High Levels of MMP-9 Messenger RNA in Periapical Inflammatory Lesions.

    Science.gov (United States)

    Campos, Kelma; Gomes, Carolina Cavalieri; Farias, Lucyana Conceição; Silva, Renato Menezes; Letra, Ariadne; Gomez, Ricardo Santiago

    2016-01-01

    Matrix metalloproteinases (MMPs) are the major class of enzymes responsible for degradation of extracellular matrix components and participate in the pathogenesis of periapical inflammatory lesions. MMP expression may be regulated by DNA methylation. The purpose of the present investigation was to analyze the expression of MMP2 and MMP9 in periapical granulomas and radicular cysts and to test the hypothesis that, in these lesions, their transcription may be modulated by DNA methylation. Methylation-specific polymerase chain reaction was used to evaluate the DNA methylation pattern of the MMP2 gene in 13 fresh periapical granuloma samples and 10 fresh radicular cyst samples. Restriction enzyme digestion was used to assess methylation of the MMP9 gene in 12 fresh periapical granuloma samples and 10 fresh radicular cyst samples. MMP2 and MMP9 messenger RNA transcript levels were measured by quantitative real-time polymerase chain reaction. All periapical lesions and healthy mucosa samples showed partial methylation of the MMP2 gene; however, periapical granulomas showed higher MMP2 mRNA expression levels than healthy mucosa (P = .014). A higher unmethylated profile of the MMP9 gene was found in periapical granulomas and radicular cysts compared with healthy mucosa. In addition, higher MMP9 mRNA expression was observed in the periapical lesions compared with healthy tissues. The present study suggests that the unmethylated status of the MMP9 gene in periapical lesions may explain the observed up-regulation of messenger RNA transcription in these lesions. Copyright © 2016 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  4. Synthesis of modified oligonucleotides for repair and replication studies of single and double radio-induced DNA lesions

    International Nuclear Information System (INIS)

    Muller, E.

    2002-01-01

    Several oxidative processes induce the formation of DNA lesions. In order to evaluate the biological and structural significance of such damage, several DNA lesions were inserted into synthetic oligonucleotides at defined sites. The research work aimed at describing the preparation of oligonucleotides t hat contained DNA damage and the evaluation of the biological properties of the lesions. A first part described the incorporation of radiation-induced lesions, namely (5'S,6S)-5',6-cyclo-5,6-dihydro-2'-deoxyuridine and (5'S,5S,6S)-5',6-cyclo-5-hydroxy-5,6-dihydro-2'-desoxyuridine into oligonucleotides. The modified DNA fragments were characterised by several spectroscopic and biochemical analyses including ESI MS, MALDI-TOF MS, CLHP and enzymatic digestions. During in vitro DNA synthesis by Taq DNA polymerase and Klenow exo fragment, the pyrimidine cyclo-nucleosides were found to block the progression of the enzymes. Then, repair studies by ADN N glycosylases, operating in the base excision repair pathway, have shown that the anhydro-nucleoside lesions were not recognised nor excised by Fpg, endo III, endo VIII, yNtg1 yNtg2 and yOgg1. Interestingly, the Latococcus lactis Fpg protein recognises (formation of a non covalent complex) but do not excise the damage. The incorporation into oligonucleotides of the (5R*) and (5S*) diastereoisomers of 1-[2-deoxy-β-D-erythro-pentofuranosyl]-5-hydroxy-hydantoin, generated by several oxidative processes was then described. In vitro DNA replication assays using modified oligonucleotides matrix showed a lethal potential of the latter base damage. Repair studies by ADN N-glycosylases showed that the damage was substrate for Fpg, endo III, endo VIII, Ntg1, Ntg2 and Fpg-L1. The rates of excision as inferred from the determination of the Michaelis kinetics constants were found to be affected by the presence of the damage. MALDI-TOF MS was used in order to gain insights into mechanistic aspects of oligonucleotides cleavage by the

  5. Nucleotide Excision Repair Lesion-Recognition Protein Rad4 Captures a Pre-Flipped Partner Base in a Benzo[a]pyrene-Derived DNA Lesion: How Structure Impacts the Binding Pathway.

    Science.gov (United States)

    Mu, Hong; Geacintov, Nicholas E; Min, Jung-Hyun; Zhang, Yingkai; Broyde, Suse

    2017-06-19

    The xeroderma pigmentosum C protein complex (XPC) recognizes a variety of environmentally induced DNA lesions and is the key in initiating their repair by the nucleotide excision repair (NER) pathway. When bound to a lesion, XPC flips two nucleotide pairs that include the lesion out of the DNA duplex, yielding a productively bound complex that can lead to successful lesion excision. Interestingly, the efficiencies of NER vary greatly among different lesions, influencing their toxicity and mutagenicity in cells. Though differences in XPC binding may influence NER efficiency, it is not understood whether XPC utilizes different mechanisms to achieve productive binding with different lesions. Here, we investigated the well-repaired 10R-(+)-cis-anti-benzo[a]pyrene-N 2 -dG (cis-B[a]P-dG) DNA adduct in a duplex containing normal partner C opposite the lesion. This adduct is derived from the environmental pro-carcinogen benzo[a]pyrene and is likely to be encountered by NER in the cell. We have extensively investigated its binding to the yeast XPC orthologue, Rad4, using umbrella sampling with restrained molecular dynamics simulations and free energy calculations. The NMR solution structure of this lesion in duplex DNA has shown that the dC complementary to the adducted dG is flipped out of the DNA duplex in the absence of XPC. However, it is not known whether the "pre-flipped" base would play a role in its recognition by XPC. Our results show that Rad4 first captures the displaced dC, which is followed by a tightly coupled lesion-extruding pathway for productive binding. This binding path differs significantly from the one deduced for the small cis-syn cyclobutane pyrimidine dimer lesion opposite mismatched thymines [ Mu , H. , ( 2015 ) Biochemistry , 54 ( 34 ), 5263 - 7 ]. The possibility of multiple paths that lead to productive binding to XPC is consistent with the versatile lesion recognition by XPC that is required for successful NER.

  6. Pitfalls and recommendations in cases of laser removal of decorative tattoos with pigmented lesions: case report and review of the literature.

    Science.gov (United States)

    Pohl, Laura; Kaiser, Kathrine; Raulin, Christian

    2013-09-01

    Pigmented lesions in decorative tattoos cause diagnostic difficulties at a clinical and dermoscopic level. In cases of laser removal of tattoos, hidden suspicious nevi may be revealed gradually. We describe the first case of a malignant melanoma that developed on a preexisting nevus within a tattoo during and between the phases of laser removal. The patient refused to undergo excision of the nevus until we made excision conditional for continued laser treatment. The English literature reports 16 cases of malignant melanoma developing in tattoos. Correlation between the placement of tattoos and the development of malignant melanoma remains unclear. Our case emphasizes the diagnostic problems of pigmented lesions within tattoos. For safety reasons, tattoos should never be placed on pigmented lesions; if they are, the tattoos should not undergo laser treatment. We suggest an excision before starting laser tattoo removal. Dermoscopic assessments on a regular basis during the period of tattoo removal are recommended.

  7. Lesion-induced DNA weak structural changes detected by pulsed EPR spectroscopy combined with site-directed spin labelling.

    Science.gov (United States)

    Sicoli, Giuseppe; Mathis, Gérald; Aci-Sèche, Samia; Saint-Pierre, Christine; Boulard, Yves; Gasparutto, Didier; Gambarelli, Serge

    2009-06-01

    Double electron-electron resonance (DEER) was applied to determine nanometre spin-spin distances on DNA duplexes that contain selected structural alterations. The present approach to evaluate the structural features of DNA damages is thus related to the interspin distance changes, as well as to the flexibility of the overall structure deduced from the distance distribution. A set of site-directed nitroxide-labelled double-stranded DNA fragments containing defined lesions, namely an 8-oxoguanine, an abasic site or abasic site analogues, a nick, a gap and a bulge structure were prepared and then analysed by the DEER spectroscopic technique. New insights into the application of 4-pulse DEER sequence are also provided, in particular with respect to the spin probes' positions and the rigidity of selected systems. The lesion-induced conformational changes observed, which were supported by molecular dynamics studies, confirm the results obtained by other, more conventional, spectroscopic techniques. Thus, the experimental approaches described herein provide an efficient method for probing lesion-induced structural changes of nucleic acids.

  8. Associations of soft flooring materials in free stalls with milk yield, clinical mastitis, teat lesions, and removal of dairy cows.

    Science.gov (United States)

    Ruud, L E; Bøe, K E; Osterås, O

    2010-04-01

    The objective was to test if there was an association between free-stall base softness and milk yield, incidence of clinical mastitis (CM), teat lesions, and removal of cows. In a questionnaire sent to 1,923 dairy farms presumed to be using free-stall housing, farmers were asked for information regarding housing and stall base; for example, the year of installation and the product name or brand of their mats or mattresses. This information was merged with data for milk yield, CM, teat lesions, and removal of cows extracted from the Norwegian Dairy Herd Recording System for the years after installation of mats or mattresses. After exclusion of invalid contributions, the data set consisted of 29,326 lactations for milk yield distributed over 363 free-stalled herds in Norway. The farms were stratified into 5 categories according to the softness of the stall surface measured as millimeter impact of a sphere with a diameter of 120 mm at 2-kN load: 1=concrete, softness of 0mm; 2=rubber, softness of 1 to 8mm; 3=soft mats, softness of 9 to 16 mm; 4=multilayer mats, softness of 17 to 24 mm; and 5=mattresses, softness over 24 mm. Lactation curves were estimated as modified Wood's lactation curves using test-day data and mixed models with repeated measurements, adjusting for days in milk, parity, and softness of free-stall flooring. Herds on concrete free-stall bases yielded 6,727+/-146 kg of milk from 5 to 305 days in milk. In comparison, herds showed a decrease of 0.3% on rubber, an increase of 2.4% on soft mats, an increase of 4.5% on multilayer mats, and an increase of 3.9% on mattresses. Compared with concrete, the hazard ratio (HR) of CM was less on rubber, multilayer mats, and mattresses [HR=0.89 (0.79-0.99), 0.85 (0.73-0.996), and 0.80 (0.73-0.88), respectively]. Compared with concrete, the HR of teat lesions was less on rubber, soft mats, multilayer mats, and mattresses [HR=0.41 (0.26-0.65), 0.33 (0.24-0.44), 0.12 (0.04-0.38), and 0.47 (0.33-0.67), respectively]. The

  9. Novel DNA lesions generated by the interaction between therapeutic thiopurines and UVA light.

    Science.gov (United States)

    Zhang, Xiaohong; Jeffs, Graham; Ren, Xiaolin; O'Donovan, Peter; Montaner, Beatriz; Perrett, Conal M; Karran, Peter; Xu, Yao-Zhong

    2007-03-01

    The therapeutic effect of the thiopurines, 6-thioguanine (6-TG), 6-mercaptopurine, and its prodrug azathioprine, depends on the incorporation of 6-TG into cellular DNA. Unlike normal DNA bases, 6-TG absorbs UVA radiation, and UVA-mediated photochemical damage of DNA 6-TG has potentially harmful side effects. When free 6-TG is UVA irradiated in solution in the presence of molecular oxygen, reactive oxygen species are generated and 6-TG is oxidized to guanine-6-sulfonate (G(SO3)) and guanine-6-thioguanine in reactions involving singlet oxygen. This conversion is prevented by antioxidants, including the dietary vitamin ascorbate. DNA G(SO3) is also the major photoproduct of 6-TG in DNA and it can be selectively introduced into DNA or oligonucleotides in vitro by mild chemical oxidation. Thermal stability measurements indicate that G(SO3) does not form stable base pairs with any of the normal DNA bases in duplex oligonucleotides and is a powerful block for elongation by Klenow DNA polymerase in primer extension experiments. In cultured human cells, DNA damage produced by 6-TG and UVA treatment is associated with replication inhibition and provokes a p53-dependent DNA damage response.

  10. Repriming by PrimPol is critical for DNA replication restart downstream of lesions and chain-terminating nucleosides.

    Science.gov (United States)

    Kobayashi, Kaori; Guilliam, Thomas A; Tsuda, Masataka; Yamamoto, Junpei; Bailey, Laura J; Iwai, Shigenori; Takeda, Shunichi; Doherty, Aidan J; Hirota, Kouji

    2016-08-02

    PrimPol is a DNA damage tolerance enzyme possessing both translesion synthesis (TLS) and primase activities. To uncover its potential role in TLS-mediated IgVλ hypermutation and define its interplay with other TLS polymerases, PrimPol(-/-) and PrimPol(-/-)/Polη(-/-)/Polζ (-/-) gene knockouts were generated in avian cells. Loss of PrimPol had no significant impact on the rate of hypermutation or the mutation spectrum of IgVλ. However, PrimPol(-/-) cells were sensitive to methylmethane sulfonate, suggesting that it may bypass abasic sites at the IgVλ segment by repriming DNA synthesis downstream of these sites. PrimPol(-/-) cells were also sensitive to cisplatin and hydroxyurea, indicating that it assists in maintaining / restarting replication at a variety of lesions. To accurately measure the relative contribution of the TLS and primase activities, we examined DNA damage sensitivity in PrimPol(-/-) cells complemented with polymerase or primase-deficient PrimPol. Polymerase-defective, but not primase-deficient, PrimPol suppresses the hypersensitivity of PrimPol(-/-) cells. This indicates that its primase, rather than TLS activity, is pivotal for DNA damage tolerance. Loss of TLS polymerases, Polη and Polζ has an additive effect on the sensitivity of PrimPol(-/-) cells. Moreover, we found that PrimPol and Polη-Polζ redundantly prevented cell death and facilitated unperturbed cell cycle progression. PrimPol(-/-) cells also exhibited increased sensitivity to a wide variety of chain-terminating nucleoside analogs (CTNAs). PrimPol could perform close-coupled repriming downstream of CTNAs and oxidative damage in vitro. Together, these results indicate that PrimPol's repriming activity plays a central role in reinitiating replication downstream from CTNAs and other specific DNA lesions.

  11. Viewing Human DNA Polymerase β Faithfully and Unfaithfully Bypass an Oxidative Lesion by Time-Dependent Crystallography

    Science.gov (United States)

    Vyas, Rajan; Reed, Andrew J.; Tokarsky, E. John; Suo, Zucai

    2015-01-01

    One common oxidative DNA lesion, 8-oxo-7,8-dihydro-2′-deoxyguanine (8-oxoG), is highly mutagenic in vivo due to its anti-conformation forming a Watson–Crick base pair with correct deoxycytidine 5′-triphosphate (dCTP) and its syn-conformation forming a Hoogsteen base pair with incorrect deoxyadenosine 5′-triphosphate (dATP). Here, we utilized time-resolved X-ray crystallography to follow 8-oxoG bypass by human DNA polymerase β (hPolβ). In the 12 solved structures, both Watson–Crick (anti-8-oxoG:anti-dCTP) and Hoogsteen (syn-8-oxoG:anti-dATP) base pairing were clearly visible and were maintained throughout the chemical reaction. Additionally, a third Mg2+ appeared during the process of phosphodiester bond formation and was located between the reacting α- and β-phosphates of the dNTP, suggesting its role in stabilizing reaction intermediates. After phosphodiester bond formation, hPolβ reopened its conformation, pyrophosphate was released, and the newly incorporated primer 3′-terminal nucleotide stacked, rather than base paired, with 8-oxoG. These structures provide the first real-time pictures, to our knowledge, of how a polymerase correctly and incorrectly bypasses a DNA lesion. PMID:25825995

  12. Nuclear DNA-Content in Mesenchymal Lesions in Dogs: Its Value as Marker of Malignancy and Extent of Genomic Instability

    Science.gov (United States)

    Boerkamp, Kim M.; Rutteman, Gerard R.; Kik, Marja J. L.; Kirpensteijn, Jolle; Schulze, Christoph; Grinwis, Guy C. M.

    2012-01-01

    DNA-aneuploidy may reflect the malignant nature of mesenchymal proliferations and herald gross genomic instability as a mechanistic factor in tumor genesis. DNA-ploidy and -index were determined by flow cytometry in canine inflammatory or neoplastic mesenchymal tissues and related to clinico-pathological features, biological behavior and p53 gene mutational status. Half of all sarcomas were aneuploid. Benign mesenchymal neoplasms were rarely aneuploid and inflammatory lesions not at all. The aneuploidy rate was comparable to that reported for human sarcomas with significant variation amongst subtypes. DNA-ploidy status in canines lacked a relation with histological grade of malignancy, in contrast to human sarcomas. While aneuploidy was related to the development of metastases in soft tissue sarcomas it was not in osteosarcomas. No relation amongst sarcomas was found between ploidy status and presence of P53 gene mutations. Heterogeneity of the DNA index between primary and metastatic sarcoma sites was present in half of the cases examined. Hypoploidy is more common in canine sarcomas and hyperploid cases have less deviation of the DNA index than human sarcomas. The variation in the presence and extent of aneuploidy amongst sarcoma subtypes indicates variation in genomic instability. This study strengthens the concept of interspecies variation in the evolution of gross chromosomal aberrations during cancer development. PMID:24213507

  13. Nuclear DNA-Content in Mesenchymal Lesions in Dogs: Its Value as Marker of Malignancy and Extent of Genomic Instability

    Energy Technology Data Exchange (ETDEWEB)

    Boerkamp, Kim M., E-mail: K.M.Boerkamp@uu.nl; Rutteman, Gerard R. [Department of Clinical Science of Companion Animals, Faculty of Veterinary Medicine, UU, Yalelaan 104, 3584 CM, Utrecht (Netherlands); Kik, Marja J. L. [Department of Pathobiology, Faculty of Veterinary Medicine, UU, Yalelaan 1, 3508 TD, Utrecht (Netherlands); Kirpensteijn, Jolle [Department of Clinical Science of Companion Animals, Faculty of Veterinary Medicine, UU, Yalelaan 104, 3584 CM, Utrecht (Netherlands); Schulze, Christoph; Grinwis, Guy C. M. [Department of Pathobiology, Faculty of Veterinary Medicine, UU, Yalelaan 1, 3508 TD, Utrecht (Netherlands)

    2012-12-03

    DNA-aneuploidy may reflect the malignant nature of mesenchymal proliferations and herald gross genomic instability as a mechanistic factor in tumor genesis. DNA-ploidy and -index were determined by flow cytometry in canine inflammatory or neoplastic mesenchymal tissues and related to clinico-pathological features, biological behavior and p53 gene mutational status. Half of all sarcomas were aneuploid. Benign mesenchymal neoplasms were rarely aneuploid and inflammatory lesions not at all. The aneuploidy rate was comparable to that reported for human sarcomas with significant variation amongst subtypes. DNA-ploidy status in canines lacked a relation with histological grade of malignancy, in contrast to human sarcomas. While aneuploidy was related to the development of metastases in soft tissue sarcomas it was not in osteosarcomas. No relation amongst sarcomas was found between ploidy status and presence of P53 gene mutations. Heterogeneity of the DNA index between primary and metastatic sarcoma sites was present in half of the cases examined. Hypoploidy is more common in canine sarcomas and hyperploid cases have less deviation of the DNA index than human sarcomas. The variation in the presence and extent of aneuploidy amongst sarcoma subtypes indicates variation in genomic instability. This study strengthens the concept of interspecies variation in the evolution of gross chromosomal aberrations during cancer development.

  14. Nuclear DNA-Content in Mesenchymal Lesions in Dogs: Its Value as Marker of Malignancy and Extent of Genomic Instability

    Directory of Open Access Journals (Sweden)

    Christoph Schulze

    2012-12-01

    Full Text Available DNA-aneuploidy may reflect the malignant nature of mesenchymal proliferations and herald gross genomic instability as a mechanistic factor in tumor genesis. DNA-ploidy and -index were determined by flow cytometry in canine inflammatory or neoplastic mesenchymal tissues and related to clinico-pathological features, biological behavior and p53 gene mutational status. Half of all sarcomas were aneuploid. Benign mesenchymal neoplasms were rarely aneuploid and inflammatory lesions not at all. The aneuploidy rate was comparable to that reported for human sarcomas with significant variation amongst subtypes. DNA-ploidy status in canines lacked a relation with histological grade of malignancy, in contrast to human sarcomas. While aneuploidy was related to the development of metastases in soft tissue sarcomas it was not in osteosarcomas. No relation amongst sarcomas was found between ploidy status and presence of P53 gene mutations. Heterogeneity of the DNA index between primary and metastatic sarcoma sites was present in half of the cases examined. Hypoploidy is more common in canine sarcomas and hyperploid cases have less deviation of the DNA index than human sarcomas. The variation in the presence and extent of aneuploidy amongst sarcoma subtypes indicates variation in genomic instability. This study strengthens the concept of interspecies variation in the evolution of gross chromosomal aberrations during cancer development.

  15. Nuclear DNA-Content in Mesenchymal Lesions in Dogs: Its Value as Marker of Malignancy and Extent of Genomic Instability

    International Nuclear Information System (INIS)

    Boerkamp, Kim M.; Rutteman, Gerard R.; Kik, Marja J. L.; Kirpensteijn, Jolle; Schulze, Christoph; Grinwis, Guy C. M.

    2012-01-01

    DNA-aneuploidy may reflect the malignant nature of mesenchymal proliferations and herald gross genomic instability as a mechanistic factor in tumor genesis. DNA-ploidy and -index were determined by flow cytometry in canine inflammatory or neoplastic mesenchymal tissues and related to clinico-pathological features, biological behavior and p53 gene mutational status. Half of all sarcomas were aneuploid. Benign mesenchymal neoplasms were rarely aneuploid and inflammatory lesions not at all. The aneuploidy rate was comparable to that reported for human sarcomas with significant variation amongst subtypes. DNA-ploidy status in canines lacked a relation with histological grade of malignancy, in contrast to human sarcomas. While aneuploidy was related to the development of metastases in soft tissue sarcomas it was not in osteosarcomas. No relation amongst sarcomas was found between ploidy status and presence of P53 gene mutations. Heterogeneity of the DNA index between primary and metastatic sarcoma sites was present in half of the cases examined. Hypoploidy is more common in canine sarcomas and hyperploid cases have less deviation of the DNA index than human sarcomas. The variation in the presence and extent of aneuploidy amongst sarcoma subtypes indicates variation in genomic instability. This study strengthens the concept of interspecies variation in the evolution of gross chromosomal aberrations during cancer development

  16. Epigenetic reprogramming of pericentromeric satellite DNA in premalignant and malignant lesions

    DEFF Research Database (Denmark)

    Brückmann, Nadine Heidi; Pedersen, Christina Bøg; Ditzel, Henrik Jørn

    2018-01-01

    on pericentromeric satellites in primary melanocytes. This suggests that polycomb bodies form in cancer cells with global DNA demethylation to control the stability of pericentromeric satellite DNA. These results reveal a novel epigenetic perturbation specific to premalignant and malignant cells thatmaybe used...... as an early diagnostic marker for detection of precancerous changes and a new therapeutic entry point. Implications: Pericentromeric satellite DNA is epigenetically reprogrammed into polycomb bodies as a premalignant event with implications for transcriptional activity and genomic stability. Mol Cancer Res...

  17. A component of DNA double-strand break repair is dependent on the spatial orientation of the lesions within the higher-order structures of chromatin

    Energy Technology Data Exchange (ETDEWEB)

    Johnston, P.J.; Bryant, P.E. (Saint Andrews Univ. (United Kingdom))

    1994-11-01

    By the use of a modified neutral filter elution procedure variations in the repair of DNA dsb have been observed between the ionising radiation sensitive mutant xrs-5 and the parent cell line CHO-K1. Conventional neutral filter elution requires harsh lysis conditions to remove higher-order chromatin structures which interfere with elution of DNA containing dsb. By lysing cells with non-ionic detergent in the presence of 2 mol dm[sup -3] salt, histone-depleted structures that retain the higher-order nuclear matrix organization, including chromatin loops, can be produced. Elution from these structures will only occur if two or more dsb lie within a single-looped domain delineated by points of attachment to the nuclear matrix. Repair experiments indicate that in CHO cells repair of dsb in loops containing multiple dsb are repaired with slow kinetics whilst dsb occurring in loops containing single dsb are repaired with fast kinetics. Xrs-5 cells are defective in the repair of multiply damaged loops. This work indicates that the spatial orientation of dsb in the higher-order structures of chromatin are a possible factor in the repair of these lesions. (Author).

  18. A component of DNA double-strand break repair is dependent on the spatial orientation of the lesions within the higher-order structures of chromatin

    International Nuclear Information System (INIS)

    Johnston, P.J.; Bryant, P.E.

    1994-01-01

    By the use of a modified neutral filter elution procedure variations in the repair of DNA dsb have been observed between the ionising radiation sensitive mutant xrs-5 and the parent cell line CHO-K1. Conventional neutral filter elution requires harsh lysis conditions to remove higher-order chromatin structures which interfere with elution of DNA containing dsb. By lysing cells with non-ionic detergent in the presence of 2 mol dm -3 salt, histone-depleted structures that retain the higher-order nuclear matrix organization, including chromatin loops, can be produced. Elution from these structures will only occur if two or more dsb lie within a single-looped domain delineated by points of attachment to the nuclear matrix. Repair experiments indicate that in CHO cells repair of dsb in loops containing multiple dsb are repaired with slow kinetics whilst dsb occurring in loops containing single dsb are repaired with fast kinetics. Xrs-5 cells are defective in the repair of multiply damaged loops. This work indicates that the spatial orientation of dsb in the higher-order structures of chromatin are a possible factor in the repair of these lesions. (Author)

  19. The SRS2 suppressor of rad6 mutations of Saccharomyces cerevisiae acts by channeling DNA lesions into the RAD52 DNA repair pathway

    International Nuclear Information System (INIS)

    Schiestl, R.H.; Prakash, S.; Prakash, L.

    1990-01-01

    rad6 mutants of Saccharomyces cerevisiae are defective in the repair of damaged DNA, DNA damage induced mutagenesis, and sporulation. In order to identify genes that can substitute for RAD6 function, the authors have isolated genomic suppressors of the UV sensitivity of rad6 deletion (rad6Δ) mutations and show that they also suppress the γ-ray sensitivity but not the UV mutagenesis or sporulation defects of rad6. The suppressors show semidominance for suppression of UV sensitivity and dominance for suppression of γ-ray sensitivity. The six suppressor mutations they isolated are all alleles of the same locus and are also allelic to a previously described suppressor of the rad6-1 nonsense mutation, SRS2. They show that suppression of rad6Δ is dependent on the RAD52 recombinational repair pathway since suppression is not observed in the rad6Δ SRS2 strain containing an additional mutation in either the RAD51, RAD52, RAD54, RAD55 or RAD57 genes. Possible mechanisms by which SRS2 may channel unrepaired DNA lesions into the RAD52 DNA repair pathway are discussed

  20. Compression of the DNA substrate by a viral packaging motor is supported by removal of intercalating dye during translocation.

    Science.gov (United States)

    Dixit, Aparna Banerjee; Ray, Krishanu; Black, Lindsay W

    2012-12-11

    Viral genome packaging into capsids is powered by high-force-generating motor proteins. In the presence of all packaging components, ATP-powered translocation in vitro expels all detectable tightly bound YOYO-1 dye from packaged short dsDNA substrates and removes all aminoacridine dye from packaged genomic DNA in vivo. In contrast, in the absence of packaging, the purified T4 packaging ATPase alone can only remove up to ∼1/3 of DNA-bound intercalating YOYO-1 dye molecules in the presence of ATP or ATP-γ-S. In sufficient concentration, intercalating dyes arrest packaging, but rare terminase mutations confer resistance. These distant mutations are highly interdependent in acquiring function and resistance and likely mark motor contact points with the translocating DNA. In stalled Y-DNAs, FRET has shown a decrease in distance from the phage T4 terminase C terminus to portal consistent with a linear motor, and in the Y-stem DNA compression between closely positioned dye pairs. Taken together with prior FRET studies of conformational changes in stalled Y-DNAs, removal of intercalating compounds by the packaging motor demonstrates conformational change in DNA during normal translocation at low packaging resistance and supports a proposed linear "DNA crunching" or torsional compression motor mechanism involving a transient grip-and-release structural change in B form DNA.

  1. Identification of the autotrophic denitrifying community in nitrate removal reactors by DNA-stable isotope probing.

    Science.gov (United States)

    Xing, Wei; Li, Jinlong; Cong, Yuan; Gao, Wei; Jia, Zhongjun; Li, Desheng

    2017-04-01

    Autotrophic denitrification has attracted increasing attention for wastewater with insufficient organic carbon sources. Nevertheless, in situ identification of autotrophic denitrifying communities in reactors remains challenging. Here, a process combining micro-electrolysis and autotrophic denitrification with high nitrate removal efficiency was presented. Two batch reactors were fed organic-free nitrate influent, with H 13 CO 3 - and H 12 CO 3 - as inorganic carbon sources. DNA-based stable-isotope probing (DNA-SIP) was used to obtain molecular evidence for autotrophic denitrifying communities. The results showed that the nirS gene was strongly labeled by H 13 CO 3 - , demonstrating that the inorganic carbon source was assimilated by autotrophic denitrifiers. High-throughput sequencing and clone library analysis identified Thiobacillus-like bacteria as the most dominant autotrophic denitrifiers. However, 88% of nirS genes cloned from the 13 C-labeled "heavy" DNA fraction showed low similarity with all culturable denitrifiers. These findings provided functional and taxonomical identification of autotrophic denitrifying communities, facilitating application of autotrophic denitrification process for wastewater treatment. Copyright © 2017 Elsevier Ltd. All rights reserved.

  2. Interaction of DNA-lesions induced by sodium fluoride and radiation and its influence in apoptotic induction in cancer cell lines

    Directory of Open Access Journals (Sweden)

    Santosh Podder

    2015-01-01

    Full Text Available Fluoride is an essential trace element but also an environmental contaminant with major sources of exposure being drinking water, food and pesticides. Previous studies showed that sodium fluoride (NaF at 5 mM or more is required to induce apoptosis and chromosome aberrations and proposed that DNA damage and apoptosis play an important role in toxicity of excessive fluoride. The aim of this study is directed to understand the nature of DNA-lesions induced by NaF by allowing its interaction with radiation induced DNA-lesions. NaF 5 mM was used after observing inability to induce DNA damages and apoptosis by single exposure with 50 μM or 1 mM NaF. Co-exposure to NaF and radiation significantly increased the frequency of aberrant metaphases and exchange aberrations in human lymphocytes and arrested the cells in G1 stage instead of apoptotic death. Flow cytometric analysis, DNA fragmentation and PARP-cleavage analysis clearly indicated that 5 mM NaF together with radiation (1 Gy induced apoptosis in both U87 and K562 cells due to down regulation of expression of anti-apoptotic proteins, like Bcl2 in U87 and inhibitors of apoptotic proteins like survivin and cIAP in K562 cells. This study herein suggested that single exposure with extremely low concentration of NaF unable to induce DNA lesions whereas higher concentration induced DNA lesions interact with the radiation-induced DNA lesions. Both are probably repaired rapidly thus showed increased interactive effect. Coexposure to NaF and radiation induces more apoptosis in cancer cell lines which could be due to increased exchange aberrations through lesions interaction and downregulating anti-apoptotic genes.

  3. Mechanisms of Insertion of dCTP and dTTP Opposite the DNA Lesion O6-Methyl-2′-deoxyguanosine by Human DNA Polymerase η*

    Science.gov (United States)

    Patra, Amitraj; Zhang, Qianqian; Guengerich, F. Peter; Egli, Martin

    2016-01-01

    O6-Methyl-2′-deoxyguanosine (O6-MeG) is a ubiquitous DNA lesion, formed not only by xenobiotic carcinogens but also by the endogenous methylating agent S-adenosylmethionine. It can introduce mutations during DNA replication, with different DNA polymerases displaying different ratios of correct or incorrect incorporation opposite this nucleoside. Of the “translesion” Y-family human DNA polymerases (hpols), hpol η is most efficient in incorporating equal numbers of correct and incorrect C and T bases. However, the mechanistic basis for this specific yet indiscriminate activity is not known. To explore this question, we report biochemical and structural analysis of the catalytic core of hpol η. Activity assays showed the truncated form displayed similar misincorporation properties as the full-length enzyme, incorporating C and T equally and extending from both. X-ray crystal structures of both dC and dT paired with O6-MeG were solved in both insertion and extension modes. The structures revealed a Watson-Crick-like pairing between O6-MeG and 2"-deoxythymidine-5"-[(α, β)-imido]triphosphate (approximating dT) at both the insertion and extension stages with formation of two H-bonds. Conversely, both the structures with O6- MeG opposite dCTP and dC display sheared configuration of base pairs but to different degrees, with formation of two bifurcated H-bonds and two single H-bonds in the structures trapped in the insertion and extension states, respectively. The structural data are consistent with the observed tendency of hpol η to insert both dC and dT opposite the O6-MeG lesion with similar efficiencies. Comparison of the hpol η active site configurations with either O6-MeG:dC or O6-MeG:dT bound compared with the corresponding situations in structures of complexes of Sulfolobus solfataricus Dpo4, a bypass pol that favors C relative to T by a factor of ∼4, helps rationalize the more error-prone synthesis opposite the lesion by hpol η. PMID:27694439

  4. The role of the HCR system in the repair of lethal lesions of Bacillus subtilis phages and their transfecting DNA damaged by radiation and alkylating agents

    International Nuclear Information System (INIS)

    Vizdalova, M.; Janovska, E.; Zhestyanikov, V.D.

    1980-01-01

    The role of the HCR system in the repair of prelethal lesions induced by UV light, γ radiation and alkylating agents was studied in the Bacillus subtilis SPP1 phage, its heat sensitive mutants (N3, N73 nad ts 1 ) and corresponding infectious DNA. The survival of phages and their transfecting DNA after treatment with UV light is substantially higher in hcr + cells than in hcr cells, the differences being more striking in intact phages than in their transfecting DNA's. Repair inhibitors reduce survival in hcr + cells: caffeine lowers the survival of UV-irradiated phage SPP1 in exponentially growing hcr + cells but has no effect on its survival in competent hcr + cells; acriflavin and ethidium bromide decrease the survival of the UV-irradiated SPP1 phage in both exponentially growing and competent hcr + cells to the level of survival observed in hcr cells; moreover, ethidium bromide lowers the number of infective centres in hcr + cells of the UV-irradiated DNA of the SPP1 phage. Repair inhibitors do not lower the survival of the UV-irradiated phages or their DNA in hcr cells. The repair mechanism under study also effectively repairs lesions induced by polyfunctional alkylating agents in the transfecting DNA's of B. subtilis phages but is not functional with lesions induced by these agents in free phages and lesions caused in the phages and their DNA by ethyl methanesulphonate or γ radiation. (author)

  5. Heavy ion-induced lesions in DNA: A theoretical model for the initial induction of DNA strand breaks and chromatin breaks

    International Nuclear Information System (INIS)

    Schmidt, J.B.

    1993-01-01

    A theoretical model has been developed and used to calculate yields and spatial distributions of DNA strand breaks resulting from the interactions of heavy ions with chromatin in aqueous systems. The three dimensional spatial distribution of ionizing events has been modeled for charged particles as a function of charge and velocity. Chromatin has been modeled as a 30 nm diameter solenoid of nucleosomal DNA. The Monte Carlo methods used by Chatterjee et al. have been applied to DNA in a chromatin conformation. Refinements to their methods include: a combined treatment of primary and low energy (<2 keV) secondary electron interactions, an improved low energy delta ray model, and the combined simulation of direct energy deposition on the DNA and attack by diffusing hydroxyl radicals. Individual particle tracks are treated independently, which is assumed to be applicable to low fluence irradiations in which multiple particle effects are negligible. Single strand break cross section open-quotes hooksclose quotes seen in experiments at very high LET appear to be due to the collapsing radial extent of the track, as predicted in the open-quotes deep sieveclose quotes hypothesis proposed by Tobias et al. Spatial distributions of lesions produced by particles have been found to depend on chromatin structure. In the future, heavy ions may be used as a tool to probe the organization of DNA in chromatin. A Neyman A-binomial variation of the open-quotes cluster modelclose quotes for the distribution of chromatin breaks per irradiated cell has been theoretically tested. The model includes a treatment of the chromatin fragment detection technique's resolution, which places a limitation on the minimum size of fragments which can be detected. The model appears to fit some of the experimental data reasonably well. However, further experimental and theoretical refinements are desirable

  6. Cancerous hyper-mutagenesis in p53 genes is possibly associated with transcriptional bypass of DNA lesions

    International Nuclear Information System (INIS)

    Rodin, S.N.; Rodin, A.S.; Juhasz, A.; Holmquist, G.P.

    2002-01-01

    The database of tumor-associated p53 base substitutions includes about 5% of tumors with two or more base substitutions. These multiplet base substitutions in one tumor are evidence for hyper-mutagenesis. Our retrospective analysis of this database indicates that most multiplets arise from a single transient hyper-mutagenic event in one cell that subsequently proliferated into a clonal tumor. The hyper-mutagenesis, 1.8x10 -4 substitutions per base pair, is detected as multiple mutations in p53 genes of tumors. It requires one strongly tumorigenic p53 substitution, usually missense, called the driver mutation. The occurrence frequencies of ancillary base substitutions, those that hitch-hike along with the driver mutation, are independent of their amino acid coding properties. In this respect, they act like neutral mutations. In support of this neutrality, we find that the frequency distribution of hitch-hiking CpG transitions along the p53 exons, their mutational spectrum, approximates the spontaneous pre-selection mutational spectrum of most human tissues and is correlated with the mutational spectrum of p53 pseudogenes in mammalian germ cells. The driver substitutions of multiplets predominantly originate along the transcribed strand while the ancillary substitutions tend to originate along the non-transcribed strand. This data is consistent with a model of time-dependent mutagenesis in non-dividing stem cells for generating multiple strand-asymmetric p53 mutations in tumors. By transcriptional bypass of DNA lesions with concomitant misincorporation, transcriptional mutagenesis generates a transient mutant p53 mRNA. The associated mutant p53 protein could allow the host cell a growth advantage, release from G 1 -arrest. Then, during subsequent DNA replication and misreading of the same lesion, the damaged base along the transcribed DNA strand would serve as the origin of the p53 base substitution that drives the hyper-mutagenic event leading to tumors with

  7. Transition-state destabilization reveals how human DNA polymerase β proceeds across the chemically unstable lesion N7-methylguanine

    Science.gov (United States)

    Ouzon-Shubeita, Hala; Lee, Seongmin

    2014-01-01

    N7-Methyl-2′-deoxyguanosine (m7dG) is the predominant lesion formed by methylating agents. A systematic investigation on the effect of m7dG on DNA replication has been difficult due to the chemical instability of m7dG. To gain insights into the m7dG effect, we employed a 2′-fluorine-mediated transition-state destabilzation strategy. Specifically, we determined kinetic parameters for dCTP insertion opposite a chemically stable m7dG analogue, 2′-fluoro-m7dG (Fm7dG), by human DNA polymerase β (polβ) and solved three X-ray structures of polβ in complex with the templating Fm7dG paired with incoming dCTP or dTTP analogues. The kinetic studies reveal that the templating Fm7dG slows polβ catalysis ∼300-fold, suggesting that m7dG in genomic DNA may impede replication by some DNA polymerases. The structural analysis reveals that Fm7dG forms a canonical Watson–Crick base pair with dCTP, but metal ion coordination is suboptimal for catalysis in the polβ-Fm7dG:dCTP complex, which partially explains the slow insertion of dCTP opposite Fm7dG by polβ. In addition, the polβ-Fm7dG:dTTP structure shows open protein conformations and staggered base pair conformations, indicating that N7-methylation of dG does not promote a promutagenic replication. Overall, the first systematic studies on the effect of m7dG on DNA replication reveal that polβ catalysis across m7dG is slow, yet highly accurate. PMID:24966350

  8. Immunohistochemical study of DNA topoisomerase I, DNA topoisomerase II alpha, p53, and Ki-67 in oral preneoplastic lesions and oral squamous cell carcinomas.

    Science.gov (United States)

    Hafian, Hilal; Venteo, Lydie; Sukhanova, Alyona; Nabiev, Igor; Lefevre, Benoît; Pluot, Michel

    2004-06-01

    Human DNA topoisomerase I (topo I) is the molecular target of the camptothecin group of anticancer drugs. Laboratory studies have shown that the cellular response to topo I-targeted drugs depends on the topo I expression and DNA replication rate and the apoptotic pathway activity. In this study, we tested potential indicators of the sensitivity of topo I-targeted drugs in 36 cases of oral squamous cell carcinoma (OSCC). Formalin-fixed, paraffin-embedded tissue sections were immunostained with monoclonal antibodies against Ki-67, p53, and topo I, and with polyclonal antibodies against DNA topoisomerase II-alpha (topo II-alpha). These markers were also tested in 18 epithelial hyperplastic lesions and 18 mild dysplasias. Immunostaining was quantified by the percentage of stained nuclei in each sample (the labeling index); 200 immunoreactive epithelial nuclei were counted per case for each antibody. The results support the possibility of using topo II-alpha staining for assessing the proliferative activity. High expression of topo II-alpha and topo I in OSCCs suggests that they may serve as potential indicators of sensitivity to topo I inhibitors. However, the apoptotic pathway assessed by p53 immunostaining was found to be uninformative. Analysis of the relationship between immunohistochemical results and clinical and pathologic parameters (the T and N stages and differentiation) showed that only the differentiation parameter correlated with the topo I expression rate. Thus, significant increase in the topo I expression in the poorly differentiated OSCCs suggests their higher sensitivity to drug treatment.

  9. Role of exonucleolytic processing and polymerase-DNA association in bypass of lesions during replication in vitro. Significance for SOS-targeted mutagenesis

    International Nuclear Information System (INIS)

    Shwartz, H.; Shavitt, O.; Livneh, Z.

    1988-01-01

    The role of exonuclease activity in trans-lesion DNA replication with Escherichia coli DNA polymerase III holoenzyme was investigated. RecA protein inhibited the 3'----5' exonuclease activity of the polymerase 2-fold when assayed in the absence of replication and had no effect on turnover of dNTPs into dNMPs. In contrast, single-stranded DNA-binding protein, which had no effect on the exonuclease activity in the absence of replication, showed a pronounced 7-fold suppression of the 3'----5' exonuclease activity during replication. The excision of incorporated dNMP alpha S residues from DNA by the 3'----5' exonuclease activity of DNA polymerase III holoenzyme was inhibited 10-20-fold; still no increase in bypass of pyrimidine photodimers was observed. Thus, in agreement with our previous results in which the exonuclease activity was inhibited at the protein level, inhibition at the DNA level also did not increase bypass of photodimers. Fractionation of the replication mixture after termination of DNA synthesis on a Bio-Gel A-5m column under conditions which favor polymerase-DNA binding yielded a termination complex which could perform turnover of dNTPs into dNMPs. Adding challenge-primed single-stranded DNA to the complex yielded a burst of DNA synthesis which was promoted most likely by DNA polymerase III holoenzyme molecules transferred from the termination complex to the challenge DNA thus demonstrating the instability of the polymerase-DNA association. Addition of a fresh sample of DNA polymerase III holoenzyme to purified termination products, which consist primarily of partially replicated molecules with nascent chains terminated at UV lesions, did not result in any net DNA synthesis as expected

  10. Residual γH2AX foci as an indication of lethal DNA lesions

    Directory of Open Access Journals (Sweden)

    Banuelos C Adriana

    2010-01-01

    Full Text Available Abstract Background Evidence suggests that tumor cells exposed to some DNA damaging agents are more likely to die if they retain microscopically visible γH2AX foci that are known to mark sites of double-strand breaks. This appears to be true even after exposure to the alkylating agent MNNG that does not cause direct double-strand breaks but does produce γH2AX foci when damaged DNA undergoes replication. Methods To examine this predictive ability further, SiHa human cervical carcinoma cells were exposed to 8 DNA damaging drugs (camptothecin, cisplatin, doxorubicin, etoposide, hydrogen peroxide, MNNG, temozolomide, and tirapazamine and the fraction of cells that retained γH2AX foci 24 hours after a 30 or 60 min treatment was compared with the fraction of cells that lost clonogenicity. To determine if cells with residual repair foci are the cells that die, SiHa cervical cancer cells were stably transfected with a RAD51-GFP construct and live cell analysis was used to follow the fate of irradiated cells with RAD51-GFP foci. Results For all drugs regardless of their mechanism of interaction with DNA, close to a 1:1 correlation was observed between clonogenic surviving fraction and the fraction of cells that retained γH2AX foci 24 hours after treatment. Initial studies established that the fraction of cells that retained RAD51 foci after irradiation was similar to the fraction of cells that retained γH2AX foci and subsequently lost clonogenicity. Tracking individual irradiated live cells confirmed that SiHa cells with RAD51-GFP foci 24 hours after irradiation were more likely to die. Conclusion Retention of DNA damage-induced γH2AX foci appears to be indicative of lethal DNA damage so that it may be possible to predict tumor cell killing by a wide variety of DNA damaging agents simply by scoring the fraction of cells that retain γH2AX foci.

  11. Residual γH2AX foci as an indication of lethal DNA lesions

    International Nuclear Information System (INIS)

    Banáth, Judit P; Klokov, Dmitry; MacPhail, Susan H; Banuelos, C Adriana; Olive, Peggy L

    2010-01-01

    Evidence suggests that tumor cells exposed to some DNA damaging agents are more likely to die if they retain microscopically visible γH2AX foci that are known to mark sites of double-strand breaks. This appears to be true even after exposure to the alkylating agent MNNG that does not cause direct double-strand breaks but does produce γH2AX foci when damaged DNA undergoes replication. To examine this predictive ability further, SiHa human cervical carcinoma cells were exposed to 8 DNA damaging drugs (camptothecin, cisplatin, doxorubicin, etoposide, hydrogen peroxide, MNNG, temozolomide, and tirapazamine) and the fraction of cells that retained γH2AX foci 24 hours after a 30 or 60 min treatment was compared with the fraction of cells that lost clonogenicity. To determine if cells with residual repair foci are the cells that die, SiHa cervical cancer cells were stably transfected with a RAD51-GFP construct and live cell analysis was used to follow the fate of irradiated cells with RAD51-GFP foci. For all drugs regardless of their mechanism of interaction with DNA, close to a 1:1 correlation was observed between clonogenic surviving fraction and the fraction of cells that retained γH2AX foci 24 hours after treatment. Initial studies established that the fraction of cells that retained RAD51 foci after irradiation was similar to the fraction of cells that retained γH2AX foci and subsequently lost clonogenicity. Tracking individual irradiated live cells confirmed that SiHa cells with RAD51-GFP foci 24 hours after irradiation were more likely to die. Retention of DNA damage-induced γH2AX foci appears to be indicative of lethal DNA damage so that it may be possible to predict tumor cell killing by a wide variety of DNA damaging agents simply by scoring the fraction of cells that retain γH2AX foci

  12. Real-time PCR detection of Brucella spp. DNA in lesions and viscera of bovine carcasses.

    Science.gov (United States)

    Sola, Marília Cristina; da Veiga Jardim, Eurione A G; de Freitas, Marcius Ribeiro; de Mesquita, Albenones José

    2014-09-01

    This study reports a real-time PCR assay for the detection of Brucella spp. associated with the FTA® Elute method in lesions observed during sanitary inspections in beef slaughter. Of the total 276 samples, 78 (28.3%) tested positive and 198 (71.7%) negative for Brucella spp. The real-time PCR technique associated with the FTA® Elute method proved to be an important tool for the diagnosis, judgment about and disposal of carcasses and viscera of slaughtered animals. Copyright © 2014 Elsevier B.V. All rights reserved.

  13. i-Motif of cytosine-rich human telomere DNA fragments containing natural base lesions

    Czech Academy of Sciences Publication Activity Database

    Dvořáková, Zuzana; Renčiuk, Daniel; Kejnovská, Iva; Školáková, Petra; Bednářová, Klára; Sagi, J.; Vorlíčková, Michaela

    2018-01-01

    Roč. 46, č. 4 (2018), s. 1624-1634 ISSN 1362-4962 R&D Projects: GA ČR(CZ) GA15-06785S; GA ČR GA17-12075S; GA ČR(CZ) GJ17-19170Y; GA MŠk EF15_003/0000477 Institutional support: RVO:68081707 Keywords : pair opening kinetics * g-quadruplex dna Subject RIV: CE - Biochemistry OBOR OECD: Biochemistry and molecular biology

  14. Direct assay of radiation-induced DNA base lesions in mammalian cells

    International Nuclear Information System (INIS)

    1992-01-01

    Adenine (Ade), 2'-deoxyadenosine (dAdo), 5'-deoxyadenosine monophosphate (dAUT), single stranded poly adenylic acid [poly (dA)], double stranded deoxyadenylic-thymidylic acid [ds poly (dA-T)] and salmon testis DNA were irradiated with 500 Gy under oxic and anoxic conditions. The major damage products were analyzed by BPLC with optical detection and quantitated in terms of the percentage of the adenosine in each model compound found as a specific damage product. Outside of the Ade free base, 8-OH-dAdo was the major oxic damage product from each model compound. The type and quantity of the major damage products depended on the sequence and conformation of the model compounds under anoxic conditions. When dAdo and dAMP were irradiated under anoxic conditions, the major damage product was either the R or S isomer of 8,5'cdAdo and little Ade or α-dAdo was observed. However, when poly(dA), poly(dA-dT), and salmon testis DNA were γ-irradiated under nitrogen, the major deoxyadenosine damage product was identified as the α-anomer of deoxyadenosine. No α-deoxyadenosine was detected after irradiation under oxic conditions. The presence of nucleotides with the α-configuration at the anomeric carbon atom in the DNA chain may have a significant effect on its tertiary structure and possibly modify its biological activity

  15. Estado de conservación de la prótesis y presencia de lesiones en mucosas de pacientes portadores de prótesis parcial removible

    OpenAIRE

    Bernal Luna, Cinthya del Pilar

    2010-01-01

    Objetivo: El objetivo del presente estudio fue determinar la relación entre el estado de conservación de la prótesis y la presencia de lesiones en mucosas de pacientes portadores de prótesis parcial removible Material y método: Se realizó un estudio descriptivo, transversal y prospectivo. En este estudio se evaluaron 50 pacientes adultos (mayores de 60 años) portadores de prótesis parcial removible. Se realizó el examen clínico odontológico y se registraron los hallazgos en una fi...

  16. Identification of an Unfolding Intermediate for a DNA Lesion Bypass Polymerase

    Science.gov (United States)

    Sherrer, Shanen M.; Maxwell, Brian A.; Pack, Lindsey R.; Fiala, Kevin A.; Fowler, Jason D.; Zhang, Jun; Suo, Zucai

    2012-01-01

    Sulfolobus solfataricusDNA Polymerase IV (Dpo4), a prototype Y-family DNA polymerase, has been well characterized biochemically and biophysically at 37 °C or lower temperatures. However, the physiological temperature of the hyperthermophile S. solfataricus is approximately 80 °C. With such a large discrepancy in temperature, the in vivo relevance of these in vitro studies of Dpo4 has been questioned. Here, we employed circular dichroism spectroscopy and fluorescence-based thermal scanning to investigate the secondary structural changes of Dpo4 over a temperature range from 26 to 119 °C. Dpo4 was shown to display a high melting temperature characteristic of hyperthermophiles. Unexpectedly, the Little Finger domain of Dpo4, which is only found in the Y-family DNA polymerases, was shown to be more thermostable than the polymerase core. More interestingly, Dpo4 exhibited a three-state cooperative unfolding profile with an unfolding intermediate. The linker region between the Little Finger and Thumb domains of Dpo4 was found to be a source of structural instability. Through site-directed mutagenesis, the interactions between the residues in the linker region and the Palm domain were identified to play a critical role in the formation of the unfolding intermediate. Notably, the secondary structure of Dpo4 was not altered when the temperature was increased from 26 to 87.5 °C. Thus, in addition to providing structural insights into the thermal stability and an unfolding intermediate of Dpo4, our work also validated the relevance of the in vitro studies of Dpo4 performed at temperatures significantly lower than 80 °C. PMID:22667759

  17. A novel method of selective removal of human DNA improves PCR sensitivity for detection of Salmonella Typhi in blood samples.

    Science.gov (United States)

    Zhou, Liqing; Pollard, Andrew J

    2012-07-27

    Enteric fever is a major public health problem, causing an estimated 21million new cases and 216,000 or more deaths every year. Current diagnosis of the disease is inadequate. Blood culture only identifies 45 to 70% of the cases and is time-consuming. Serological tests have very low sensitivity and specificity. Clinical samples obtained for diagnosis of enteric fever in the field generally have blood, so that even PCR-based methods, widely used for detection of other infectious diseases, are not a straightforward option in typhoid diagnosis. We developed a novel method to enrich target bacterial DNA by selective removal of human DNA from blood samples, enhancing the sensitivity of PCR tests. This method offers the possibility of improving PCR assays directly using clinical specimens for diagnosis of this globally important infectious disease. Blood samples were mixed with ox bile for selective lysis of human blood cells and the released human DNA was then digested with addition of bile resistant micrococcal nuclease. The intact Salmonella Typhi bacteria were collected from the specimen by centrifugation and the DNA extracted with QIAamp DNA mini kit. The presence of Salmonella Typhi bacteria in blood samples was detected by PCR with the fliC-d gene of Salmonella Typhi as the target. Micrococcal nuclease retained activity against human blood DNA in the presence of up to 9% ox bile. Background human DNA was dramatically removed from blood samples through the use of ox bile lysis and micrococcal nuclease for removal of mammalian DNA. Consequently target Salmonella Typhi DNA was enriched in DNA preparations and the PCR sensitivity for detection of Salmonella Typhi in spiked blood samples was enhanced by 1,000 fold. Use of a combination of selective ox-bile blood cell lysis and removal of human DNA with micrococcal nuclease significantly improves PCR sensitivity and offers a better option for improved typhoid PCR assays directly using clinical specimens in diagnosis of

  18. Managing Carious Lesions

    DEFF Research Database (Denmark)

    Schwendicke, F; Frencken, J E; Bjørndal, L

    2016-01-01

    should be prioritized, while in shallow or moderately deep lesions, restoration longevity becomes more important. For teeth with shallow or moderately deep cavitated lesions, carious tissue removal is performed according toselective removal to firm dentine.In deep cavitated lesions in primary......The International Caries Consensus Collaboration undertook a consensus process and here presents clinical recommendations for carious tissue removal and managing cavitated carious lesions, including restoration, based on texture of demineralized dentine. Dentists should manage the disease dental...

  19. The beta subunit modulates bypass and termination at UV lesions during in vitro replication with DNA polymerase III holoenzyme of Escherichia coli

    International Nuclear Information System (INIS)

    Shavitt, O.; Livneh, Z.

    1989-01-01

    The cycling time of DNA polymerase III holoenzyme during replication of UV-irradiated single-stranded (ss) DNA was longer than with unirradiated DNA (8 versus 3 min, respectively), most likely due to slow dissociation from lesion-terminated nascent DNA strands. Initiation of elongation on primed ssDNA was not significantly inhibited by the presence of UV lesions as indicated by the identical distribution of replication products synthesized at early and late reaction times and by the identical duration of the initial synthesis bursts on both unirradiated and UV-irradiated DNA templates. When replication was performed with DNA polymerase III* supplemented with increasing quantities of purified beta 2 subunit, the cycling time on UV-irradiated DNA decreased from 14.8 min at 1.7 nM beta 2 down to 6 min at 170 nM beta 2, a concentration in which beta 2 was in large excess over the polymerase. In parallel to the reduction in cycling time, also the bypass frequency of cyclobutane-photodimers decreased with increasing beta 2 concentration, and at 170 nM beta 2, bypass of photodimers was essentially eliminated. It has been shown that polymerase complexes with more than one beta 2 per polymerase molecule were formed at high beta 2 concentrations. It is plausible that polymerase complexes obtained under high beta 2 concentration dissociate from lesion-terminated primers faster than polymerase complexes formed at a low beta 2 concentration. This is expected to favor termination over bypass at pyrimidine photodimers and thus decrease their bypass frequency. These results suggest that the beta 2 subunit might act as a sensor for obstacles to replication caused by DNA damage, and that it terminates elongation at these sites by promoting dissociation. The intracellular concentration of beta 2 was estimated to be 250 nM

  20. Application of thiopropyl sepharose 6B for removal of PCR inhibitors from DNA extracts of a thigh bone recovered from the sea

    DEFF Research Database (Denmark)

    Sørensen, Erik; Hansen, Steen Holger; Eriksen, Birthe

    2003-01-01

    for the removal of PCR inhibitors in DNA extracts originating from stains on clothing. Here we show that TS is efficient also for the removal of inhibitors from PCR extracts from a highly decomposed human thigh bone. TS treatment, however, leads to a substantial loss of DNA making the technique best suited when...

  1. Expression of DNA repair proteins MSH2, MLH1 and MGMT in human benign and malignant thyroid lesions: An immunohistochemical study

    Science.gov (United States)

    Giaginis, Constantinos; Michailidi, Christina; Stolakis, Vasileios; Alexandrou, Paraskevi; Tsourouflis, Gerasimos; Klijanienko, Jerzy; Delladetsima, Ioanna; Theocharis, Stamatios

    2011-01-01

    Summary Background DNA repair is a major defense mechanism, which contributes to the maintenance of genetic sequence, and minimizes cell death, mutation rates, replication errors, DNA damage persistence and genomic instability. Alterations in the expression levels of proteins participating in DNA repair mechanisms have been associated with several aspects of cancer biology. The present study aimed to evaluate the clinical significance of DNA repair proteins MSH2, MLH1 and MGMT in benign and malignant thyroid lesions. Material/Methods MSH2, MLH1 and MGMT protein expression was assessed immunohistochemically on paraffin-embedded thyroid tissues from 90 patients with benign and malignant lesions. Results The expression levels of MLH1 was significantly upregulated in cases with malignant compared to those with benign thyroid lesions (p=0.038). The expression levels of MGMT was significantly downregulated in malignant compared to benign thyroid lesions (p=0.001). Similar associations for both MLH1 and MGMT between cases with papillary carcinoma and hyperplastic nodules were also noted (p=0.014 and p=0.026, respectively). In the subgroup of malignant thyroid lesions, MSH2 downregulation was significantly associated with larger tumor size (p=0.031), while MLH1 upregulation was significantly associated with the presence of lymphatic and vascular invasion (p=0.006 and p=0.002, respectively). Conclusions Alterations in the mismatch repair proteins MSH2 and MLH1 and the direct repair protein MGMT may result from tumor development and/or progression. Further studies are recommended to draw definite conclusions on the clinical significance of DNA repair proteins in thyroid neoplasia. PMID:21358597

  2. Excision repair of gamma-ray-induced alkali-stable DNA lesions with the help of γ-endonuclease from Micrococcus luteus

    International Nuclear Information System (INIS)

    Tomilin, N.V.; Barenfeld, L.S.

    1979-01-01

    γ-endonuclease Y, an enzyme that hydrolyses phosphodiester bonds at alkali-stable lesions in γ-irradiated (N 2 , tris buffer) DNA, has been partially purified from Micrococcus luteus. The enzyme has a molecular weight of about 19 000, induces single-strand breaks with 3'OH-5'PO 4 termini and contains endonuclease activity towards DNA treated with 7-bromomethylbenz(a)anthracene. γ-endonuclease Y induces breaks in OsO 4 -treated poly(dA-dT) and apparently is specific towards γ-ray-induced base lesions of the t' type. The complete excision repair of γ-endonuclease Y substrate sites has been performed in vitro by γ-endonuclease Y, DNA polymerase and ligase. (author)

  3. Excision repair of gamma-ray-induced alkali-stable DNA lesions with the help of. gamma. -endonuclease from Micrococcus luteus

    Energy Technology Data Exchange (ETDEWEB)

    Tomilin, N V; Barenfeld, L S [AN SSSR, Leningrad. Inst. Tsitologii

    1979-03-01

    ..gamma..-endonuclease Y, an enzyme that hydrolyses phosphodiester bonds at alkali-stable lesions in ..gamma..-irradiated (N/sub 2/, tris buffer) DNA, has been partially purified from Micrococcus luteus. The enzyme has a molecular weight of about 19 000, induces single-strand breaks with 3'OH-5'PO/sub 4/ termini and contains endonuclease activity towards DNA treated with 7-bromomethylbenz(a)anthracene. ..gamma..-endonuclease Y induces breaks in OsO/sub 4/-treated poly(dA-dT) and apparently is specific towards ..gamma..-ray-induced base lesions of the t' type. The complete excision repair of ..gamma..-endonuclease Y substrate sites has been performed in vitro by ..gamma..-endonuclease Y, DNA polymerase and ligase.

  4. Object-action dissociation: A voxel-based lesion-symptom mapping study on 102 patients after glioma removal

    Directory of Open Access Journals (Sweden)

    Alberto Pisoni

    Full Text Available Data concerning the neural basis of noun and verb processing are inconsistent. Some authors assume that action-verb processing is based on frontal areas while nouns processing relies on temporal regions; others argue that the circuits processing verbs and nouns are closely interconnected in a predominantly left-lateralized fronto-temporal-parietal network; yet, other researchers consider that the primary motor cortex plays a crucial role in processing action verbs. In the present study, one hundred and two patients with a tumour either in the right or left hemisphere were submitted to picture naming of objects and actions before and after surgery. To test the effect of specific brain regions in object and action naming, patients' lesions were mapped and voxel-lesion-symptom mapping (VLSM was computed. Behavioural results showed that left-brain damaged patients were significantly more impaired than right brain-damaged patients. The VLSM showed that these two grammatical classes are segregated in the left hemisphere. In particular, scores in naming of objects correlated with damage to the anterior temporal region, while scores in naming of actions correlated with lesions in the parietal areas and in the posterior temporal cortex. In addition, VLSM analyses carried out on non-linguistic tasks were not significant, confirming that the regions associated with deficits in object and action naming were not generally engaged in all cognitive tasks. Finally, the involvement of subcortical pathways was investigated and the inferior longitudinal fasciculus proved to play a role in object naming, while no specific bundle was identified for actions. Keywords: Object action dissociation, Temporal lesion, Frontal lesion, Voxel-based lesion symptom mapping

  5. NMR studies of abasic sites in DNA duplexes: Deoxyadenosine stacks into the helix opposite acyclic lesions

    International Nuclear Information System (INIS)

    Kalnik, M.W.; Chang, Chienneng; Johnson, F.; Grollman, A.P.; Patel, D.J.

    1989-01-01

    Proton and phosphorus NMR studies are reported for two complementary nonanucleotide duplexes containing acyclic abasic sites. The first duplex, d(C-A-T-G-A-G-T-A-C)·d(G-T-A-C-P-C-A-T-G), contains an acyclic propanyl moiety, P, located opposite a deoxyadenosine at the center of the helix (designated AP P 9-mer duplex). The second duplex, d(C-A-T-G-A-G-T-A-C-)·d(G-T-A-C-E-C-A-T-G), contains a similarly located acyclic ethanyl moiety, E (designated AP E 9-mer duplex). The ethanyl moiety is one carbon shorter than the natural carbon-phosphodiester backbone of a single nucleotide unit of DNA. The majority of the exchangeable and nonexchangeable base and sugar protons in both the AP P 9-mer and AP E 9-mer duplexes, including those at the abasic site, have been assigned by recording and analyzing two-dimensional phase-sensitive NOESY data sets in H 2 O and D 2 O solution between -5 and 5 degree C. These spectroscopic observations establish that A5 inserts into the helix opposite the abasic site (P14 and El14) and stacks between the flanking G4·C15 and G6·C13 Watson-Crick base pairs in both the AP P 9-mer and AP E 9-mer duplexes. Proton NMR parameters for the Ap P 9-mer and AP E 9-mer duplexes are similar to those reported previously. These proton NMR experiments demonstrate that the structures at abasic sites are very similar whether the five-membered ring is open or closed or whether the phosphodiester backbone is shortened by one carbon atom. Phosphorus spectra of the AP P 9-mer and AP E 9-mer duplexes (5 degree C) indicate that the backbone conformation is similarly perturbed at three phosphodiester backbone torsion angles

  6. Enzymatic removal of O6-ethylguanine from mitochondrial DNA in rat tissues exposed to N-ethyl-N-nitrosourea in vivo

    International Nuclear Information System (INIS)

    Satoh, M.S.; Huh, N.; Rajewsky, M.F.; Kuroki, T.

    1988-01-01

    DNA repair is essential for maintaining the integrity of the genetic material, and a number of DNA repair mechanisms have been fairly well characterized for the nuclear DNA of eukaryotic cells as well as prokaryotes. However, little is know about DNA repair in mitochondria. Using highly sensitive immunoanalytical methods to detect specific DNA alkylation products, the authors found active removal of O 6 -ethyl-2'-deoxyguanosine (O 6 -EtdGuo) from rat liver mitochondrial DNA after pulse-exposure to N-ethyl-N-nitrosourea in vivo. In the kidney, O 6 -EtdGuo was removed from mitochondrial DNA with moderate efficiency, but nearly no removal was observed from the DNA of brain mitochondria. Among the rat tissues examined, the kinetics of O 6 -EtdGuo elimination from mitochondrial DNA was very similar to the kinetics of removal from nuclear DNA. O 4 -Ethyl-2'-deoxythymidine, another premutagenic DNA ethylation product, was stable in both mitochondrial and nuclear DNA of rat liver

  7. DNA damage and autophagy

    International Nuclear Information System (INIS)

    Rodriguez-Rocha, Humberto; Garcia-Garcia, Aracely; Panayiotidis, Mihalis I.; Franco, Rodrigo

    2011-01-01

    Both exogenous and endogenous agents are a threat to DNA integrity. Exogenous environmental agents such as ultraviolet (UV) and ionizing radiation, genotoxic chemicals and endogenous byproducts of metabolism including reactive oxygen species can cause alterations in DNA structure (DNA damage). Unrepaired DNA damage has been linked to a variety of human disorders including cancer and neurodegenerative disease. Thus, efficient mechanisms to detect DNA lesions, signal their presence and promote their repair have been evolved in cells. If DNA is effectively repaired, DNA damage response is inactivated and normal cell functioning resumes. In contrast, when DNA lesions cannot be removed, chronic DNA damage triggers specific cell responses such as cell death and senescence. Recently, DNA damage has been shown to induce autophagy, a cellular catabolic process that maintains a balance between synthesis, degradation, and recycling of cellular components. But the exact mechanisms by which DNA damage triggers autophagy are unclear. More importantly, the role of autophagy in the DNA damage response and cellular fate is unknown. In this review we analyze evidence that supports a role for autophagy as an integral part of the DNA damage response.

  8. DNA Repair Mechanisms and the Bypass of DNA Damage in Saccharomyces cerevisiae

    Science.gov (United States)

    Boiteux, Serge; Jinks-Robertson, Sue

    2013-01-01

    DNA repair mechanisms are critical for maintaining the integrity of genomic DNA, and their loss is associated with cancer predisposition syndromes. Studies in Saccharomyces cerevisiae have played a central role in elucidating the highly conserved mechanisms that promote eukaryotic genome stability. This review will focus on repair mechanisms that involve excision of a single strand from duplex DNA with the intact, complementary strand serving as a template to fill the resulting gap. These mechanisms are of two general types: those that remove damage from DNA and those that repair errors made during DNA synthesis. The major DNA-damage repair pathways are base excision repair and nucleotide excision repair, which, in the most simple terms, are distinguished by the extent of single-strand DNA removed together with the lesion. Mistakes made by DNA polymerases are corrected by the mismatch repair pathway, which also corrects mismatches generated when single strands of non-identical duplexes are exchanged during homologous recombination. In addition to the true repair pathways, the postreplication repair pathway allows lesions or structural aberrations that block replicative DNA polymerases to be tolerated. There are two bypass mechanisms: an error-free mechanism that involves a switch to an undamaged template for synthesis past the lesion and an error-prone mechanism that utilizes specialized translesion synthesis DNA polymerases to directly synthesize DNA across the lesion. A high level of functional redundancy exists among the pathways that deal with lesions, which minimizes the detrimental effects of endogenous and exogenous DNA damage. PMID:23547164

  9. Multiple effects of fluorescent light on repair of ultraviolet-induced DNA lesions in cultured goldfish cells

    International Nuclear Information System (INIS)

    Uchida, Nobuhiro; Mitani, Hiroshi; Shima, Akihiro

    1995-01-01

    It is known that fluorescent light illumination prior to UV irradiation (FL preillumination) of cultured fish cells increases photorepair (PR) ability. In the present study, it was found that FL preillumination also enhanced UV resistance of logarithmically growing cells in the dark. This enhancement of UV resistance differs from induction of PR because it was not suppressed by cyclohexamide (CH) and it occurred immediately after FL preillumination. The effects of FL preillumination on repair of UV-induced DNA lesions in the dark were examined by an endonuclease-sensitive site assay to measure the repair of cyclobutyl pyrimidine dimers, and by enzyme-linked immunosorbent assay to quantitate the repair of (6-4) photoproducts. It was found that excision repair ability for (6-4) photoproducts in the genome overall was increased by FL preillumination. Moreover, a decrease in (6-4) photoproducts by FL illumination immediately after UV irradiation of the cells was found, the decrement being enhanced by FL preillumination with or without CH. (author)

  10. Multiple effects of fluorescent light on repair of ultraviolet-induced DNA lesions in cultured goldfish cells

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Nobuhiro; Mitani, Hiroshi; Shima, Akihiro [Tokyo Univ. (Japan). Lab. of Radiation Biology

    1995-01-01

    It is known that fluorescent light illumination prior to UV irradiation (FL preillumination) of cultured fish cells increases photorepair (PR) ability. In the present study, it was found that FL preillumination also enhanced UV resistance of logarithmically growing cells in the dark. This enhancement of UV resistance differs from induction of PR because it was not suppressed by cyclohexamide (CH) and it occurred immediately after FL preillumination. The effects of FL preillumination on repair of UV-induced DNA lesions in the dark were examined by an endonuclease-sensitive site assay to measure the repair of cyclobutyl pyrimidine dimers, and by enzyme-linked immunosorbent assay to quantitate the repair of (6-4) photoproducts. It was found that excision repair ability for (6-4) photoproducts in the genome overall was increased by FL preillumination. Moreover, a decrease in (6-4) photoproducts by FL illumination immediately after UV irradiation of the cells was found, the decrement being enhanced by FL preillumination with or without CH. (author).

  11. Poly(hydroxyethyl methacrylate) based affinity membranes for in vitro removal of anti-dsDNA antibodies from SLE plasma.

    Science.gov (United States)

    Uzun, Lokman; Yavuz, Handan; Osman, Bilgen; Celik, Hamdi; Denizli, Adil

    2010-07-01

    The preparation of polymeric membrane using affinity technology for application in blood filtration devices is described here. DNA attached poly(hydroxyethyl methacrylate) (PHEMA) based microporous affinity membrane was prepared for selective removal of anti-dsDNA antibodies from systemic lupus erythematosus (SLE) patient plasma in in vitro. In order to further increase blood-compatibility of affinity membrane, aminoacid based comonomer N-methacryloyl-L-alanine (MAAL) was included in the polymerization recipe. PHEMAAL membrane was produced by a photopolymerization technique and then characterized by swelling tests and scanning electron microscope (SEM) studies. Blood-compatibility tests were also performed. The water swelling ratio of PHEMAAL membrane increased significantly (133.2%) compared with PHEMA (58%). PHEMAAL membrane has large pores around in the range of 5-10 microm. All the clotting times increased when compared with PHEMA membrane. Loss of platelets and leukocytes was very low. DNA loading was 7.8 mg/g. There was a very low anti-dsDNA-antibody adsorption onto the plain PHEMAAL membrane, about 78 IU/g. The PHEMAAL-DNA membrane adsorbed anti-dsDNA-antibody in the range of 10-68 x 10(3)IU/g from SLE plasma. Anti-dsDNA-antibody concentration decreased significantly from 875 to 144 IU/ml with the time. Anti-dsDNA-antibodies could be repeatedly adsorbed and eluted without noticeable loss in the anti-dsDNA-antibody adsorption amount. (c) 2010 Elsevier B.V. All rights reserved.

  12. Silver (I) as DNA glue: Ag+-mediated guanine pairing revealed by removing Watson-Crick constraints

    Science.gov (United States)

    Swasey, Steven M.; Leal, Leonardo Espinosa; Lopez-Acevedo, Olga; Pavlovich, James; Gwinn, Elisabeth G.

    2015-01-01

    Metal ion interactions with DNA have far-reaching implications in biochemistry and DNA nanotechnology. Ag+ is uniquely interesting because it binds exclusively to the bases rather than the backbone of DNA, without the toxicity of Hg2+. In contrast to prior studies of Ag+ incorporation into double-stranded DNA, we remove the constraints of Watson-Crick pairing by focusing on homo-base DNA oligomers of the canonical bases. High resolution electro-spray ionization mass spectrometry reveals an unanticipated Ag+-mediated pairing of guanine homo-base strands, with higher stability than canonical guanine-cytosine pairing. By exploring unrestricted binding geometries, quantum chemical calculations find that Ag+ bridges between non-canonical sites on guanine bases. Circular dichroism spectroscopy shows that the Ag+-mediated structuring of guanine homobase strands persists to at least 90 °C under conditions for which canonical guanine-cytosine duplexes melt below 20 °C. These findings are promising for DNA nanotechnology and metal-ion based biomedical science. PMID:25973536

  13. Silver (I) as DNA glue: Ag(+)-mediated guanine pairing revealed by removing Watson-Crick constraints.

    Science.gov (United States)

    Swasey, Steven M; Leal, Leonardo Espinosa; Lopez-Acevedo, Olga; Pavlovich, James; Gwinn, Elisabeth G

    2015-05-14

    Metal ion interactions with DNA have far-reaching implications in biochemistry and DNA nanotechnology. Ag(+) is uniquely interesting because it binds exclusively to the bases rather than the backbone of DNA, without the toxicity of Hg(2+). In contrast to prior studies of Ag(+) incorporation into double-stranded DNA, we remove the constraints of Watson-Crick pairing by focusing on homo-base DNA oligomers of the canonical bases. High resolution electro-spray ionization mass spectrometry reveals an unanticipated Ag(+)-mediated pairing of guanine homo-base strands, with higher stability than canonical guanine-cytosine pairing. By exploring unrestricted binding geometries, quantum chemical calculations find that Ag(+) bridges between non-canonical sites on guanine bases. Circular dichroism spectroscopy shows that the Ag(+)-mediated structuring of guanine homobase strands persists to at least 90 °C under conditions for which canonical guanine-cytosine duplexes melt below 20 °C. These findings are promising for DNA nanotechnology and metal-ion based biomedical science.

  14. Silver (I) as DNA glue: Ag+-mediated guanine pairing revealed by removing Watson-Crick constraints

    Science.gov (United States)

    Swasey, Steven M.; Leal, Leonardo Espinosa; Lopez-Acevedo, Olga; Pavlovich, James; Gwinn, Elisabeth G.

    2015-05-01

    Metal ion interactions with DNA have far-reaching implications in biochemistry and DNA nanotechnology. Ag+ is uniquely interesting because it binds exclusively to the bases rather than the backbone of DNA, without the toxicity of Hg2+. In contrast to prior studies of Ag+ incorporation into double-stranded DNA, we remove the constraints of Watson-Crick pairing by focusing on homo-base DNA oligomers of the canonical bases. High resolution electro-spray ionization mass spectrometry reveals an unanticipated Ag+-mediated pairing of guanine homo-base strands, with higher stability than canonical guanine-cytosine pairing. By exploring unrestricted binding geometries, quantum chemical calculations find that Ag+ bridges between non-canonical sites on guanine bases. Circular dichroism spectroscopy shows that the Ag+-mediated structuring of guanine homobase strands persists to at least 90 °C under conditions for which canonical guanine-cytosine duplexes melt below 20 °C. These findings are promising for DNA nanotechnology and metal-ion based biomedical science.

  15. Glycosaminoglycan-resistant and pH-sensitive lipid-coated DNA complexes produced by detergent removal method.

    Science.gov (United States)

    Lehtinen, Julia; Hyvönen, Zanna; Subrizi, Astrid; Bunjes, Heike; Urtti, Arto

    2008-10-21

    Cationic polymers are efficient gene delivery vectors in in vitro conditions, but these carriers can fail in vivo due to interactions with extracellular polyanions, i.e. glycosaminoglycans (GAG). The aim of this study was to develop a stable gene delivery vector that is activated at the acidic endosomal pH. Cationic DNA/PEI complexes were coated by 1,2-dioleylphosphatidylethanolamine (DOPE) and cholesteryl hemisuccinate (CHEMS) (3:2 mol/mol) using two coating methods: detergent removal and mixing with liposomes prepared by ethanol injection. Only detergent removal produced lipid-coated DNA complexes that were stable against GAGs, but were membrane active at low pH towards endosome mimicking liposomes. In relation to the low cellular uptake of the coated complexes, their transfection efficacy was relatively high. PEGylation of the coated complexes increased their cellular uptake but reduced the pH-sensitivity. Detergent removal was thus a superior method for the production of stable, but acid activatable, lipid-coated DNA complexes.

  16. The proofreading 3'→5' exonuclease activity of DNA polymerases: a kinetic barrier to translesion DNA synthesis

    International Nuclear Information System (INIS)

    Khare, Vineeta; Eckert, Kristin A.

    2002-01-01

    The 3'→5' exonuclease activity intrinsic to several DNA polymerases plays a primary role in genetic stability; it acts as a first line of defense in correcting DNA polymerase errors. A mismatched basepair at the primer terminus is the preferred substrate for the exonuclease activity over a correct basepair. The efficiency of the exonuclease as a proofreading activity for mispairs containing a DNA lesion varies, however, being dependent upon both the DNA polymerase/exonuclease and the type of DNA lesion. The exonuclease activities intrinsic to the T4 polymerase (family B) and DNA polymerase γ (family A) proofread DNA mispairs opposite endogenous DNA lesions, including alkylation, oxidation, and abasic adducts. However, the exonuclease of the Klenow polymerase cannot discriminate between correct and incorrect bases opposite alkylation and oxidative lesions. DNA damage alters the dynamics of the intramolecular partitioning of DNA substrates between the 3'→5' exonuclease and polymerase activities. Enzymatic idling at lesions occurs when an exonuclease activity efficiently removes the same base that is preferentially incorporated by the DNA polymerase activity. Thus, the exonuclease activity can also act as a kinetic barrier to translesion synthesis (TLS) by preventing the stable incorporation of bases opposite DNA lesions. Understanding the downstream consequences of exonuclease activity at DNA lesions is necessary for elucidating the mechanisms of translesion synthesis and damage-induced cytotoxicity

  17. Are dinucleoside monophosphates relevant models for the study of DNA intrastrand cross-link lesions? The example of g[8-5m]T.

    Science.gov (United States)

    Garrec, Julian; Dumont, Elise

    2014-07-21

    Oxidatively generated tandem lesions such as G[8-5m]T pose a potent threat to genome integrity. Direct experimental studies of the kinetics and thermodynamics of a specific lesion within DNA are very challenging, mostly due to the variety of products that can be formed in oxidative conditions. Dinucleoside monophosphates (DM) involving only the reactive nucleobases in water represent appealing alternative models on which most physical chemistry and structural techniques can be applied. However, it is not yet clear how relevant these models are. Here, we present QM/MM MD simulations of the cyclization step involved in the formation of G[8-5m]T from the guanine-thymine (GpT) DM in water, with the aim of comparing our results to our previous investigation of the same reaction in DNA ( Garrec , J. , Patel , C. , Rothlisberger , U. , and Dumont , E. ( 2012 ) J. Am. Chem. Soc. 134 , 2111 - 2119 ). We show that, despite the different levels of preorganization of the two systems, the corresponding reactions share many energetic and structural characteristics. The main difference lies in the angle between the G and T bases, which is slightly higher in the transition state (TS) and product of the reaction in water than in the reaction in DNA. This effect is due to the Watson-Crick H-bonds, which are absent in the {GpT+water} system and restrain the relative positioning of the reactive nucleobases in DNA. However, since the lesion is accommodated easily in the DNA macromolecule, the induced energetic penalty is relatively small. The high similarity between the two reactions strongly supports the use of GpT in water as a model of the corresponding reaction in DNA.

  18. Directional character of spreading of vasogenic cerebral edema after radiation damage in rhesus monkeys, and effects of removal of the primary lesion

    International Nuclear Information System (INIS)

    Wakisaka, Shinichiro; Iguchi, Takahiko; Nakagaki, Hiroyuki; Tanaka, Akira; Black, P.; O'Neill, R.R.; Caveness, W.F.

    1986-01-01

    Five pubescent rhesus monkeys were exposed to 35 Gy of orthovoltage x-irradiation in a single dose to the right visual cortex. Twenty to 36 weeks later the irradiated region broke down rather abruptly. Steep rise of cerebrospinal fluid (CSF) protein and lactic dehydrogenase (LDH) indicated disruption of blood brain barrier (BBB) and tissue breakdown. Visual evoked response (VER), funduscopic and clinical findings suggested disfunction of neural tissues and increased intracranial pressure. Extraordinary brain swelling and distortion were observed at the time of sacrifice. The most striking finding was that the ipsilateral middle and inferior temporal gyri, where radiation did not affect directly, were selectively swollen and edematous sparing the superior temporal gyrus. Corticocortical neuronal connections between visual cortex and inferior convexity of the temporal lobe has been demonstrated by Kuypers et al. Our previous studies also disclosed selective swelling of other remote visual association areas, i. e., ipsilateral lateral geniculate body and uncinate fasciculus. Thus, edema fluid might propagate from the site of the lesion through the anatomic pathways. In the group of monkeys, which received surgical removals of damaged right occipital lobes where BBB was disrupted, CSF protein and LDH drastically returned to the normal base line values after the surgery. Furthermore, no swelling of ipsilateral middle and inferior temporal gyri was observed in this group at the time of sacrifice, indicating that spreaded vasogenic edema could be subdued by removing the primary lesion. (author)

  19. Folic Acid Supplementation Delays Atherosclerotic Lesion Development by Modulating MCP1 and VEGF DNA Methylation Levels In Vivo and In Vitro

    Science.gov (United States)

    Cui, Shanshan; Li, Wen; Lv, Xin; Wang, Pengyan; Gao, Yuxia; Huang, Guowei

    2017-01-01

    The pathogenesis of atherosclerosis has been partly acknowledged to result from aberrant epigenetic mechanisms. Accordingly, low folate levels are considered to be a contributing factor to promoting vascular disease because of deregulation of DNA methylation. We hypothesized that increasing the levels of folic acid may act via an epigenetic gene silencing mechanism to ameliorate atherosclerosis. Here, we investigated the atheroprotective effects of folic acid and the resultant methylation status in high-fat diet-fed ApoE knockout mice and in oxidized low-density lipoprotein-treated human umbilical vein endothelial cells. We analyzed atherosclerotic lesion histology, folate concentration, homocysteine concentration, S-adenosylmethionine (SAM) and S-adenosylhomocysteine (SAH), and DNA methyltransferase activity, as well as monocyte chemotactic protein-1 (MCP1) and vascular endothelial growth factor (VEGF) expression and promoter methylation. Folic acid reduced atherosclerotic lesion size in ApoE knockout mice. The underlying folic acid protective mechanism appears to operate through regulating the normal homocysteine state, upregulating the SAM: SAH ratio, elevating DNA methyltransferase activity and expression, altering MCP1 and VEGF promoter methylation, and inhibiting MCP1 and VEGF expression. We conclude that folic acid supplementation effectively prevented atherosclerosis by modifying DNA methylation through the methionine cycle, improving DNA methyltransferase activity and expression, and thus changing the expression of atherosclerosis-related genes. PMID:28475147

  20. APE1, the DNA base excision repair protein, regulates the removal of platinum adducts in sensory neuronal cultures by NER

    International Nuclear Information System (INIS)

    Kim, Hyun-Suk; Guo, Chunlu; Thompson, Eric L.; Jiang, Yanlin; Kelley, Mark R.; Vasko, Michael R.; Lee, Suk-Hee

    2015-01-01

    Peripheral neuropathy is one of the major side effects of treatment with the anticancer drug, cisplatin. One proposed mechanism for this neurotoxicity is the formation of platinum adducts in sensory neurons that could contribute to DNA damage. Although this damage is largely repaired by nuclear excision repair (NER), our previous findings suggest that augmenting the base excision repair pathway (BER) by overexpressing the repair protein APE1 protects sensory neurons from cisplatin-induced neurotoxicity. The question remains whether APE1 contributes to the ability of the NER pathway to repair platinum-damage in neuronal cells. To examine this, we manipulated APE1 expression in sensory neuronal cultures and measured Pt-removal after exposure to cisplatin. When neuronal cultures were treated with increasing concentrations of cisplatin for two or three hours, there was a concentration-dependent increase in Pt-damage that peaked at four hours and returned to near baseline levels after 24 h. In cultures where APE1 expression was reduced by ∼80% using siRNA directed at APE1, there was a significant inhibition of Pt-removal over eight hours which was reversed by overexpressing APE1 using a lentiviral construct for human wtAPE1. Overexpressing a mutant APE1 (C65 APE1), which only has DNA repair activity, but not its other significant redox-signaling function, mimicked the effects of wtAPE1. Overexpressing DNA repair activity mutant APE1 (226 + 177APE1), with only redox activity was ineffective suggesting it is the DNA repair function of APE1 and not its redox-signaling, that restores the Pt-damage removal. Together, these data provide the first evidence that a critical BER enzyme, APE1, helps regulate the NER pathway in the repair of cisplatin damage in sensory neurons

  1. APE1, the DNA base excision repair protein, regulates the removal of platinum adducts in sensory neuronal cultures by NER

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Suk [Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202 (United States); Guo, Chunlu; Thompson, Eric L. [Department of Pharmacology and Toxicology, Indianapolis, IN 46202 (United States); Jiang, Yanlin [Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Kelley, Mark R. [Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202 (United States); Department of Pharmacology and Toxicology, Indianapolis, IN 46202 (United States); Department of Pediatrics and Herman B Wells Center for Pediatric Research, Indiana University School of Medicine, Indianapolis, IN 46202 (United States); Vasko, Michael R. [Department of Pharmacology and Toxicology, Indianapolis, IN 46202 (United States); Lee, Suk-Hee, E-mail: slee@iu.edu [Department of Biochemistry and Molecular Biology, Indianapolis, IN 46202 (United States)

    2015-09-15

    Peripheral neuropathy is one of the major side effects of treatment with the anticancer drug, cisplatin. One proposed mechanism for this neurotoxicity is the formation of platinum adducts in sensory neurons that could contribute to DNA damage. Although this damage is largely repaired by nuclear excision repair (NER), our previous findings suggest that augmenting the base excision repair pathway (BER) by overexpressing the repair protein APE1 protects sensory neurons from cisplatin-induced neurotoxicity. The question remains whether APE1 contributes to the ability of the NER pathway to repair platinum-damage in neuronal cells. To examine this, we manipulated APE1 expression in sensory neuronal cultures and measured Pt-removal after exposure to cisplatin. When neuronal cultures were treated with increasing concentrations of cisplatin for two or three hours, there was a concentration-dependent increase in Pt-damage that peaked at four hours and returned to near baseline levels after 24 h. In cultures where APE1 expression was reduced by ∼80% using siRNA directed at APE1, there was a significant inhibition of Pt-removal over eight hours which was reversed by overexpressing APE1 using a lentiviral construct for human wtAPE1. Overexpressing a mutant APE1 (C65 APE1), which only has DNA repair activity, but not its other significant redox-signaling function, mimicked the effects of wtAPE1. Overexpressing DNA repair activity mutant APE1 (226 + 177APE1), with only redox activity was ineffective suggesting it is the DNA repair function of APE1 and not its redox-signaling, that restores the Pt-damage removal. Together, these data provide the first evidence that a critical BER enzyme, APE1, helps regulate the NER pathway in the repair of cisplatin damage in sensory neurons.

  2. Using CF11 cellulose columns to inexpensively and effectively remove human DNA from Plasmodium falciparum-infected whole blood samples

    Directory of Open Access Journals (Sweden)

    Venkatesan Meera

    2012-02-01

    Full Text Available Abstract Background Genome and transcriptome studies of Plasmodium nucleic acids obtained from parasitized whole blood are greatly improved by depletion of human DNA or enrichment of parasite DNA prior to next-generation sequencing and microarray hybridization. The most effective method currently used is a two-step procedure to deplete leukocytes: centrifugation using density gradient media followed by filtration through expensive, commercially available columns. This method is not easily implemented in field studies that collect hundreds of samples and simultaneously process samples for multiple laboratory analyses. Inexpensive syringes, hand-packed with CF11 cellulose powder, were recently shown to improve ex vivo cultivation of Plasmodium vivax obtained from parasitized whole blood. This study was undertaken to determine whether CF11 columns could be adapted to isolate Plasmodium falciparum DNA from parasitized whole blood and achieve current quantity and purity requirements for Illumina sequencing. Methods The CF11 procedure was compared with the current two-step standard of leukocyte depletion using parasitized red blood cells cultured in vitro and parasitized blood obtained ex vivo from Cambodian patients with malaria. Procedural variations in centrifugation and column size were tested, along with a range of blood volumes and parasite densities. Results CF11 filtration reliably produces 500 nanograms of DNA with less than 50% human DNA contamination, which is comparable to that obtained by the two-step method and falls within the current quality control requirements for Illumina sequencing. In addition, a centrifuge-free version of the CF11 filtration method to isolate P. falciparum DNA at remote and minimally equipped field sites in malaria-endemic areas was validated. Conclusions CF11 filtration is a cost-effective, scalable, one-step approach to remove human DNA from P. falciparum-infected whole blood samples.

  3. Breast lesions with imaging-histologic discordance during US-guided 14G automated core biopsy: can the directional vacuum-assisted removal replace the surgical excision? Initial findings

    International Nuclear Information System (INIS)

    Kim, Min Jung; Kim, Eun-Kyung; Lee, Ji Young; Youk, Ji Hyun; Oh, Ki Keun; Park, Byeong-Woo; Kim, Seung-Il; Kim, Haeryoung

    2007-01-01

    The purpose of this study was to determine the frequency of carcinoma at percutaneous directional vacuum-assisted removal (DVAR) in women with imaging-histologic discordance during ultrasound (US)-guided automated core needle biopsy, and to determine the role of DVAR in breast lesions with imaging-histologic discordance. A US-guided 14-gauge automated core needle biopsy was performed on 837 consecutive lesions. Imaging-histologic discordance was prospectively considered in 33 of 634 benign biopsies. DVAR was recommended in those lesions. Among the 33 lesions, 26 lesions that underwent subsequent DVAR or surgical excision made up our study population. Medical records, imaging studies, and histologic findings were reviewed. Among the 26 lesions, 18 lesions underwent subsequent US-guided DVAR, with 8-gauge probes for 15 of the lesions, and 11-gauge for three of the lesions. Two lesions were diagnosed as having carcinoma (2/18, 11.1% of upgrade rate; 3.1-32.8% CI). The remaining eight lesions underwent subsequent surgical excision, and carcinoma was diagnosed in one case (12.5% of upgrade rate; 2.2-47.1% CI). A US-guided DVAR of the breast mass with imaging-histologic discordance during US-guided 14-gauge automated core needle biopsy is a valuable alternative to surgery as a means of obtaining a definitive histological diagnosis. (orig.)

  4. Visual search among items of different salience: removal of visual attention mimics a lesion in extrastriate area V4.

    Science.gov (United States)

    Braun, J

    1994-02-01

    In more than one respect, visual search for the most salient or the least salient item in a display are different kinds of visual tasks. The present work investigated whether this difference is primarily one of perceptual difficulty, or whether it is more fundamental and relates to visual attention. Display items of different salience were produced by varying either size, contrast, color saturation, or pattern. Perceptual masking was employed and, on average, mask onset was delayed longer in search for the least salient item than in search for the most salient item. As a result, the two types of visual search presented comparable perceptual difficulty, as judged by psychophysical measures of performance, effective stimulus contrast, and stability of decision criterion. To investigate the role of attention in the two types of search, observers attempted to carry out a letter discrimination and a search task concurrently. To discriminate the letters, observers had to direct visual attention at the center of the display and, thus, leave unattended the periphery, which contained target and distractors of the search task. In this situation, visual search for the least salient item was severely impaired while visual search for the most salient item was only moderately affected, demonstrating a fundamental difference with respect to visual attention. A qualitatively identical pattern of results was encountered by Schiller and Lee (1991), who used similar visual search tasks to assess the effect of a lesion in extrastriate area V4 of the macaque.

  5. A serological study of removal of UV-induced photoproducts in the DNA of tetrahymena pyriformis GL: influence of caffeine, quinacrine and chloroquine

    International Nuclear Information System (INIS)

    Lakhanisky, Th.; Hendrickx, B.; Mouton, R.F.; Cornelis, J.J.

    1979-01-01

    Antisera that recognise specifically UV-photoproducts in DNA have been used to follow the elimination of photolesions in UV irradiated Tetrahymena pyriformis. The amount of bound tritium-labelled antibodies to nuclei has been estimated by autoradiography. Curves of dose-response of DNA photo-products, their elimination by dark repair, and effect of caffeine, quinacrine, and chloroquine on the disappearance of UV-lesions have been evaluated. (author)

  6. Repair of endogenous and ionizing radiation-induced DNA damages: mechanisms and biological functions

    International Nuclear Information System (INIS)

    Boiteux, S.

    2002-01-01

    The cellular DNA is continuously exposed to endogenous and exogenous stress. Oxidative stress due to cellular metabolism is the major cause of endogenous DNA damage. On the other hand, ionizing radiation (IR) is an important exogenous stress. Both induce similar DNA damages: damaged bases, abasic sites and strand breakage. Most of these lesions are lethal and/or mutagenic. The survival of the cell is managed by efficient and accurate DNA repair mechanisms that remove lesions before their replication or transcription. DNA repair pathways involved in the removal of IR-induced lesions are briefly described. Base excision repair (BER) is mostly involved in the removal of base damage, abasic sites and single strand breaks. In contrast, DNA double strand breaks are mostly repaired by non-homologous end joining (NHEJ) or homologous recombination (HR). How DNA repair pathways prevent cancer process is also discussed. (author)

  7. Harman inhibits the removal of pyrimidine dimers from the DNA of human cells

    International Nuclear Information System (INIS)

    Castellani, A.; Setlow, R.B.

    1981-01-01

    Normal human fibroblasts were UV-irradiated and incubated for 6 hr with harman. The losses of sites, in the extracted DNA, sensitive to a UV specific endonuclease were determined as precision measures of the excision of UV-induced pyrimidine dimers. Harman inhibited excision, rising from approx. 30% inhibition at 200 μM to 75% inhibition at 500 μM

  8. Recurring DNA copy number gain at chromosome 9p13 plays a role in the activation of multiple candidate oncogenes in progressing oral premalignant lesions

    International Nuclear Information System (INIS)

    Towle, Rebecca; Tsui, Ivy F L; Zhu, Yuqi; MacLellan, Sara; Poh, Catherine F; Garnis, Cathie

    2014-01-01

    Genomic alteration at chromosome 9p has been previously reported as a frequent and critical event in oral premalignancy. While this alteration is typically reported as a loss driven by selection for CDKN2A deactivation (at 9p21.3), we detect a recurrent DNA copy number gain of ∼2.49 Mbp at chromosome 9p13 in oral premalignant lesions (OPLs) that later progressed to invasive lesions. This recurrent alteration event has been validated using fluorescence in situ hybridization in an independent set of OPLs. Analysis of publicly available gene expression datasets aided in identifying three oncogene candidates that may have driven selection for DNA copy number increases in this region (VCP, DCTN3, and STOML2). We performed in vitro silencing and activation experiments for each of these genes in oral cancer cell lines and found that each gene is independently capable of upregulating proliferation and anchorage-independent growth. We next analyzed the activity of each of these genes in biopsies of varying histological grades that were obtained from a diseased oral tissue field in a single patient, finding further molecular evidence of parallel activation of VCP, DCTN3, and STOML2 during progression from normal healthy tissue to invasive oral carcinoma. Our results support the conclusion that DNA gain at 9p13 is important to the earliest stages of oral tumorigenesis and that this alteration event likely contributes to the activation of multiple oncogene candidates capable of governing oral cancer phenotypes

  9. Detection of the Epstein-Barr Virus and DNA-Topoisomerase II-α in Recurrent and Nonrecurrent Giant Cell Lesion of the Jawbones

    Directory of Open Access Journals (Sweden)

    Manal M. Zyada

    2013-01-01

    Full Text Available The aims of this study were to determine whether the expression of Topo II- correlates with presence of EBV in giant cell lesion of the jawbones and whether it is predictive of clinical biologic behavior of these lesions. Paraffin-embedded tissues from 8 recurrent and 7 nonrecurrent cases of bony GCLs and 9 peripheral giant cell lesions (PGCLs as a control group were assessed for the expression of EBV and Topo II- using immunohistochemistry. The results showed positive staining for Topo II- in mononuclear stromal cells (MSCs and multinucleated giant cells (MGCs. Student t-test showed that mean Topo II- labelling index (LI in recurrent cases was significantly higher than that in non-recurrent cases (. Moreover, Spearman's correlation coefficients method showed a significant correlation between DNA Topo II- LI and both of gender and site in these lesions. Moderate EBV expression in relation to the highest Topo II- LI was observed in two cases of GCT. It was concluded that high Topo II- LIs could be identified as reliable predicators for the clinical behavior of GCLs. Moreover, EBV has no etiological role in the benign CGCLs in contrast to its role in the pathogenesis of GCTs.

  10. Removal of pyrimidine dimers from Saccharomyces cerevisiae nuclear DNA under nongrowth conditions as detected by a sensitive, enzymatic assay

    Energy Technology Data Exchange (ETDEWEB)

    Reynolds, R J [Tennessee Univ., Oak Ridge (USA). Graduate School of Biomedical Sciences

    1978-04-01

    A sensitive and quantitative procedure for the detection of pyrimidine dimers in yeast nuclear DNA is described. The assay employs dimer-specific, endonuclease activities from Micrococcus luteus together with DNA sedimentation through calibrated, alkaline sucrose gradients to detect endonuclease-induced, single-strand breaks. Breaks were induced in a dose-dependent manner from 0 to 80 J m/sup -2/ at 254 nm and in numbers equivalent to the numbers of dimers induced by similar doses. Endonuclease-sensitive sites in the wild-type, haploid strain S288C, after irradiation with 5 J m/sup -2/ (254 nm), were removed in less than 5 min when cells were incuba ted in buffer (pH 7.0) at 28/sup 0/C. After irra diation with dos es from 30 to 100 J m/sup -2/ site removal in S288C required longer postirradiation incubations and was about 90% complete. In a radiation-sensitive strain carrying the mutant allele rad 4-3 the number of endonuclease-sensitive sites remained constant for 6 h after irradiation with 5 J m/sup -2/. The retention of sites in this strain indicates that it is defective in the excision of pyrimidine dimers. (Auth.

  11. Ex vivo assessment of protective effects of carvacrol against DNA lesions induced in primary rat cells by visible light excited methylene blue (VL+MB).

    Science.gov (United States)

    Slamenova, D; Horvathova, E; Chalupa, I; Wsolova, L; Navarova, J

    2011-01-01

    Carvacrol belongs to frequently occurring phenolic components of essential oils (EOs) and it is present in many kinds of plants. Biological effect of this phenol derivative on human beings is however not sufficiently known. The present study was undertaken to evaluate the level of VL+MB-induced oxidative DNA lesions in hepatocytes and testicular cells (freshly isolated from control or carvacrol-watered rats) by the modified single cell gel electrophoresis (SCGE). The results showed that carvacrol significantly reduced the level of VL+MB-induced oxidized bases (EndoIII- and Fpg-sensitive sites) only in hepatocytes but not in testicular cells. Chromosomal aberration assay of primary hepatocytes, isolated from control or carvacrol-watered rats did not testify any genotoxic activity of carvacrol. We suggest that in vivo applied synthetic carvacrol, whose antioxidative activity was confirmed by DPPH assay, exhibits primarily a strong hepatoprotective activity against oxidative damage to DNA.

  12. New method for estimating clustering of DNA lesions induced by physical/chemical mutagens using fluorescence anisotropy.

    Science.gov (United States)

    Akamatsu, Ken; Shikazono, Naoya; Saito, Takeshi

    2017-11-01

    We have developed a new method for estimating the localization of DNA damage such as apurinic/apyrimidinic sites (APs) on DNA using fluorescence anisotropy. This method is aimed at characterizing clustered DNA damage produced by DNA-damaging agents such as ionizing radiation and genotoxic chemicals. A fluorescent probe with an aminooxy group (AlexaFluor488) was used to label APs. We prepared a pUC19 plasmid with APs by heating under acidic conditions as a model for damaged DNA, and subsequently labeled the APs. We found that the observed fluorescence anisotropy (r obs ) decreases as averaged AP density (λ AP : number of APs per base pair) increases due to homo-FRET, and that the APs were randomly distributed. We applied this method to three DNA-damaging agents, 60 Co γ-rays, methyl methanesulfonate (MMS), and neocarzinostatin (NCS). We found that r obs -λ AP relationships differed significantly between MMS and NCS. At low AP density (λ AP  < 0.001), the APs induced by MMS seemed to not be closely distributed, whereas those induced by NCS were remarkably clustered. In contrast, the AP clustering induced by 60 Co γ-rays was similar to, but potentially more likely to occur than, random distribution. This simple method can be used to estimate mutagenicity of ionizing radiation and genotoxic chemicals. Copyright © 2017 Elsevier Inc. All rights reserved.

  13. The contribution of thermally labile sugar lesions to DNA double-strand break formation in cells grown in the presence of BrdU.

    Science.gov (United States)

    Li, Fanghua; Cheng, Yanlei; Iliakis, George

    2015-04-01

    Radiosensitization by bromodeoxyuridine (BrdU) is commonly attributed to an increase in the yield of double-strand breaks (DSB) in the DNA and an associated decrease in the reparability of these lesions. Radiation chemistry provides a mechanism for the increased yield of DSB through the generation, after bromine loss, of a highly reactive uracilyl radical that attacks the sugar moiety of the nucleotide to produce a single-strand break (SSB). The effects underpinning DSB repair inhibition remain, in contrast, incompletely characterized. A possible source of reduced reparability is a change in the nature or complexity of the DSB in BrdU-substituted DNA. Recent studies show that DSB-complexity or DSB-nature may also be affected by the presence within the cluster of thermally labile sugar lesions (TLSL) that break the DNA backbone only if they chemically evolve to SSB, a process thought to occur within the first hour post-irradiation. Since BrdU radiosensitization might be associated with increased yields and reduced reparability of DSB, we investigated whether BrdU underpins these effects by shifting the balance in the generation of TLSL. We employed asymmetric-field-inversion gel electrophoresis (AFIGE), a pulsed-field gel electrophoresis (PFGE) method to quantitate DSB in a battery of five cells lines grown in the presence of different concentrations of BrdU. We measured specifically the yields of promptly forming DSB (prDSB) using low temperature lysis protocols, and the yields of total DSB (tDSB = prDSB + tlDSB; tlDSB form after evolution to SSB of TLSL) using high temperature lysis protocols. We report that incorporation of BrdU generates similar increases in the formation of tlDSB and prDSB, but variations are noted among the different cell lines tested. The similar increase in the yields of tlDSB and prDSB in BrdU substituted DNA showed that shifts in the yields of these forms of lesions could not be invoked to explain BrdU radiosensitization.

  14. A rapid tattoo removal technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol.

    Science.gov (United States)

    Sardana, Kabir; Ranjan, Rashmi; Kochhar, Atul M; Mahajan, Khushbu Goel; Garg, Vijay K

    2015-01-01

    Tattoo removal has evolved over the years and though Q-switched laser is the 'workhorse' laser, it invariably requires multiple sittings, which are dependent on numerous factors, including the skin colour, location of the tattoo, age of the tattoo, colour of pigment used, associated fibrosis and the kind of tattoo treated. Though ablative lasers, both pulsed CO2 and Er:YAG, have been used for recalcitrant tattoos, very few studies have been done comparing them with pigment-specific lasers. Our study was based on the premise that ablating the epidermis overlying the tattoo pigment with Er:YAG could help in gaining better access to the pigment which would enable the Q-switched laser to work effectively with less beam scattering. A study of rapid tattoo removal (RTR) technique using a combination of pulsed Er:YAG and Q-Switched Nd:YAG in a split lesion protocol. This prospective study was undertaken during 2010-13 at a laser Clinic in the Maulana Azad Medical College, New Delhi. A total of 10 patients were recruited, 5 of amateur tattoo and 5 of professional tattoo. After informed consent each tattoo was arbitrarily 'split' into two parts. One part was treated with QS Nd:YAG laser(1064 nm) and the other part with Er:YAG laser immediately followed by the QS Nd:YAG. The laser treatments were repeated at 6-week intervals until the tattoo pigment had cleared. On the combination side in subsequent sittings only the QS Nd:YAG was used, to minimize repetitive ablation. To ensure consistency in the intervention methods a trained dermatologist who was independent of the treatment delivery randomly rated 10% of the procedures. The mean improvement achieved by the Q-switched laser (2.93) was less than the combination laser (3.85) side (p = 0.001) and needed more sessions (3.8 vs. 1.6; p = 0.001). There was a statistically significant difference in the improvement on the combination side till the second session. On the combination side patients required a maximum of 2 sessions

  15. Oxidative DNA damage of peripheral blood polymorphonuclear leukocytes, selectively induced by chronic arsenic exposure, is associated with extent of arsenic-related skin lesions

    International Nuclear Information System (INIS)

    Pei, Qiuling; Ma, Ning; Zhang, Jing; Xu, Wenchao; Li, Yong; Ma, Zhifeng; Li, Yunyun; Tian, Fengjie; Zhang, Wenping; Mu, Jinjun; Li, Yuanfei; Wang, Dongxing; Liu, Haifang; Yang, Mimi; Ma, Caifeng; Yun, Fen

    2013-01-01

    8-OHdG staining of PMN nuclei was paralleled by increased debris of cells. ► Oxidative DNA damage of PMNs is associated with arsenic-related skin lesions.

  16. Distinct kinetics of DNA repair protein accumulation at DNA lesions and cell cycle-dependent formation of gammaH2AX- and NBS1-positive repair foci

    Czech Academy of Sciences Publication Activity Database

    Suchánková, Jana; Kozubek, Stanislav; Legartová, Soňa; Sehnalová, Petra; Kuntzinger, T.; Bártová, Eva

    2015-01-01

    Roč. 107, č. 12 (2015), s. 440-454 ISSN 0248-4900 R&D Projects: GA ČR(CZ) GBP302/12/G157; GA ČR(CZ) GA13-07822S Institutional support: RVO:68081707 Keywords : Cell cycle * DNA repair * Interphase Subject RIV: BO - Biophysics Impact factor: 2.552, year: 2015

  17. DNA repair kinetic of hydrogen peroxide and UVA/B induced lesions in peripheral blood leucocytes from xeroderma pigmentosum patients and healthy subjects.

    Science.gov (United States)

    Gonzalez, Elio A Prieto; Mudry, Marta D; Palermo, Ana Maria

    2014-01-01

    The objective of the present work was to study the fine kinetics of DNA repair in xeroderma pigmentosum (XP) syndrome, a complex disorder linked to a deficiency in repair that increases cancer susceptibility. The repair process was evaluated by the comet assay (CA) in cells from 2 XP patients and 9 controls exposed to UVA/B (UVA 366/UVB 280 nm) and H2O2 (150 μM) at temperatures of 4, 15, and 37°C. Samples were taken at 2-min intervals during the first 10 min to analyze the "fine kinetics" repair during the initial phase of the curve, and then at 15, 20, 25, 30, 45, 60, and 120 min. CA evaluation of DNA repair activity points to BER/NER initiation in the first 30 min with both inductors at 37°C and 15°C, but final comet length showed differences according to treatment. Repair kinetics during 120 min showed a good correlation with clinical features in both XP patients. Differences in final comet length were less pronounced in XP cells treated with H2O2 than with UVA/B, probably because the peroxide produces mainly base oxidation but less bulky lesions; UVA/B generates a mixture of both. These findings reinforce the value of CA in testing in DNA repair ability or exposure monitoring.

  18. The caretakers of the genome. Repair of DNA lesions induced by ultraviolet-light and ionizing radiation

    International Nuclear Information System (INIS)

    Boiteux, S.; Radicella, J.P.

    2000-01-01

    The DNA contained in the nucleus of each of our cells daily suffers of thousand damages caused by solar ultraviolet radiations or ionizing radiations, with a natural or not origin, agents able to modify the genetic information. This information stays stable. True caretakers of the genome repair the DNA, provided that the cell is not over-taken by the level of the attack. Alterations of the repair mechanism are at the origin of extremely severe syndromes. The failure of one of these caretakers of the genome, the O.G.G.1 gene, seems implicated in the cancer development. It can be a lead to discover a predisposition to radioinduced or caused by other toxic agents cancers. (N.C.)

  19. DNA repair deficiency in neurodegeneration

    DEFF Research Database (Denmark)

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

    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...

  20. Coexposure to benzo[a]pyrene plus UVA induced DNA double strand breaks: visualization of Ku assembly in the nucleus having DNA lesions

    International Nuclear Information System (INIS)

    Toyooka, Tatsushi; Ibuki, Yuko; Koike, Manabu; Ohashi, Norio; Takahashi, Sentaro; Goto, Rensuke

    2004-01-01

    Benzo[a]pyrene (BaP) is a ubiquitous environmental pollutant with potential carcinogenicity. It has been shown that BaP, upon UVA irradiation, synergistically induced oxidative DNA damage, but other DNA damage was not confirmed. In this study, we examined whether coexposure to BaP plus UVA induces double strand breaks (DSBs) using xrs-5 cells, deficient in the repair of DSBs (Ku80 mutant), and whether Ku translocates involving the formation of DSBs. BaP plus UVA had a significant cytotoxic effect on CHO-K1 cells and an even more drastic effect on Ku80-deficient, xrs-5 cells, suggesting that the DSBs were generated by coexposure to BaP plus UVA. The DSBs were repaired in CHO-K1 cells within 30 min, but not in xrs-5 cells, indicating the involvement of a non-homologous end joining, which needs Ku proteins. Furthermore, we succeeded in visualizing that Ku80 rapidly assembled to the exposed region, in which DSBs might be generated, and clarified that the presence of both Ku70 and Ku80 was important for their accumulation

  1. Association between human papillomavirus and Epstein - Barr virus DNA and gene promoter methylation of RB1 and CDH1 in the cervical lesions: a transversal study.

    Science.gov (United States)

    McCormick, Thaís M; Canedo, Nathalie H S; Furtado, Yara L; Silveira, Filomena A; de Lima, Roberto J; Rosman, Andréa D F; Almeida Filho, Gutemberg L; Carvalho, Maria da Glória da C

    2015-06-02

    Human papillomavirus (HPV) inactivates the retinoblastoma 1 (RB1) gene by promoter methylation and reduces cellular E-cadherin expression by overexpression of DNA methyltransferase 1 (DNMT1). The Epstein-Barr virus (EBV) is an oncogenic virus that may be related to cervical carcinogenesis. In gastric cancer, it has been demonstrated that E-cadherin gene (CDH1) hypermethylation is associated with DNMT1 overexpression by EBV infection. Our aim was to analyze the gene promoter methylation frequency of RB1 and CDH1 and verify the association between that methylation frequency and HPV and EBV infection in cervical lesions. Sixty-five samples were obtained from cervical specimens: 15 normal cervices, 17 low-grade squamous intraepithelial lesions (LSIL), 15 high-grade squamous intraepithelial lesions (HSIL), and 18 cervical cancers. HPV and EBV DNA testing was performed by PCR, and the methylation status was verified by MSP. HPV frequency was associated with cervical cancer cases (p = 0.005) but not EBV frequency (p = 0.732). Viral co-infection showed a statistically significant correlation with cancer (p = 0.027). No viral infection was detected in 33.3% (5/15) of controls. RB1 methylated status was associated with cancer (p = 0.009) and HPV infection (p = 0.042). CDH1 methylation was not associated with cancer (p = 0.181). Controls and LSIL samples did not show simultaneous methylation, while both genes were methylated in 27.8% (5/18) of cancer samples. In the presence of EBV, CDH1 methylation was present in 27.8% (5/18) of cancer samples. Only cancer cases presented RB1 promoter methylation in the presence of HPV and EBV (33.3%). The methylation status of both genes increased with disease progression. With EBV, RB1 methylation was a tumor-associated event because only the cancer group presented methylated RB1 with HPV infection. HPV infection was shown to be significantly correlated with cancer conditions. The global methylation frequency was

  2. Human cystic echinococcosis in Turkey: a preliminary study on DNA polymorphisms of hydatid cysts removed from confirmed patients.

    Science.gov (United States)

    Orsten, Serra; Boufana, Belgees; Ciftci, Turkmen; Akinci, Devrim; Karaagaoglu, Ergun; Ozkuyumcu, Cumhur; Casulli, Adriano; Akhan, Okan

    2018-04-01

    Cystic echinococcosis caused by the larval stages of Echinococcus granulosus sensu lato s.l is endemic in Turkey with a high public health impact particularly in rural areas. The aim of this study was to investigate the genetic variation and population structure of E. granulosus s.s using metacestode isolates removed from surgically confirmed patients originating from several regions in Turkey and to investigate the occurrence of autochthonous transmission. Using DNA extracted from a total of 46 human-derived CE isolates, we successfully analysed an 827-bp fragment within the cox1 mitochondrial gene and confirmed the causative agent of human cystic echinococcosis in patients included in this study to be Echinococcus granulosus s.s (G1 and G3 genotypes). The haplotype parsimony network consisted of 28 haplotypes arranged within three main clusters and the neutrality indices were both negative and significant indicating negative selection or population expansion. The assessment carried out in this study using GenBank nucleotide sequence data from Turkey for sheep and cattle hosts demonstrated the importance of autochthonous transmission with sheep, cattle and humans harbouring the same haplotypes. Further studies are required to investigate the biological significance, if any, of E. granulosus s.s haplotypes and the genetic variability of CE from human patients using longer nucleotide sequences and a larger sample set.

  3. HPV16-E2 induces prophase arrest and activates the cellular DNA damage response in vitro and in precursor lesions of cervical carcinoma.

    Science.gov (United States)

    Xue, Yuezhen; Toh, Shen Yon; He, Pingping; Lim, Thimothy; Lim, Diana; Pang, Chai Ling; Abastado, Jean-Pierre; Thierry, Françoise

    2015-10-27

    Cervical intraepithelial neoplasia (CIN) is caused by human papillomavirus (HPV) infection and is the precursor to cervical carcinoma. The completion of the HPV productive life cycle depends on the expression of viral proteins which further determines the severity of the cervical neoplasia. Initiation of the viral productive replication requires expression of the E2 viral protein that cooperates with the E1 viral DNA helicase. A decrease in the viral DNA replication ability and increase in the severity of cervical neoplasia is accompanied by simultaneous elevated expression of E6 and E7 oncoproteins. Here we reveal a novel and important role for the HPV16-E2 protein in controlling host cell cycle during malignant transformation. We showed that cells expressing HPV16-E2 in vitro are arrested in prophase alongside activation of a sustained DDR signal. We uncovered evidence that HPV16-E2 protein is present in vivo in cells that express both mitotic and DDR signals specifically in CIN3 lesions, immediate precursors of cancer, suggesting that E2 may be one of the drivers of genomic instability and carcinogenesis in vivo.

  4. Prevalência de lesões bucais associadas ao uso de próteses dentárias removíveis em um serviço de estomatologia Prevalencia de lesiones bucales asociadas al uso de prótesis dentales removibles, en un servicio de estomatología Prevalence of oral lesions associated with use of removable dental prostheses in a Stomatology service

    Directory of Open Access Journals (Sweden)

    Gardênia Matos Paraguassú

    2011-09-01

    Full Text Available As próteses dentárias removíveis restabelecem a função e estética do sistema estomatognático, embora possam causar injúrias aos tecidos bucais. O objetivo deste estudo é avaliar a prevalência de lesões bucais relacionadas ao uso de próteses dentárias removíveis. Foi realizada a revisão de prontuários dos pacientes atendidos no Serviço de Estomatologia da Faculdade de Odontologia da Universidade Federal da Bahia, no periodo de junho de 2006 à dezembro de 2007. Dos 28 indivíduos usuários de próteses dentárias removíveis, 25 (89,3 % apresentaram alguma alteração na mucosa bucal, sendo que 42,8 % destas apresentavam-se mal-adaptadas. A hiperplasia fibrobrosa inflamatória (29,42 %, candidíase crônica atrófica (20,6 %, queilite angular (8,82 % e úlcera traumática (8,82 % foram as lesões mais prevalentes, e a mucosa alveolar (35,3 % e o palato duro (29,4 % os sítios anatômicos mais acometidos. Estes resultados reafirmam a importância da confecção de próteses adequadas, da necessidade de se realizar controles periódicos e fornecer instruções sobre higiene bucal aos pacientes que vierem fazer uso de próteses dentárias removíveis.Las prótesis dentales removibles restauran la función y la estética del sistema estomatognático, pero pueden causar daños a los tejidos bucales. El objetivo de este estudio fue evaluar la prevalencia de lesiones bucales relacionadas con el uso de prótesis removibles. Se realizó una revisión del historial de los pacientes atendidos en el Servicio de Estomatología de la Facultad de Odontología de la Universidad Federal de Bahía de Brasil, del mes de junio del año 2006 al mes de diciembre del año 2007. De los 28 individuos que usaron prótesis dentales removibles, 25 mostraron anormalidades en la mucosa bucal, para un 89,3 %; y el 42,8 % de estas estaban mal adaptadas. Dentro de las lesiones se encuentra la hiperplasia fibrosa inflamatoria en el 29,42 % de la muestra, la

  5. hREV3 is essential for error-prone translesion synthesis past UV or benzo[a]pyrene diol epoxide-induced DNA lesions in human fibroblasts

    Energy Technology Data Exchange (ETDEWEB)

    Li Ziqiang; Zhang Hong; McManus, Terrence P.; McCormick, J. Justin; Lawrence, Christopher W.; Maher, Veronica M

    2002-12-29

    In S. cerevisiae, the REV3 gene, encoding the catalytic subunit of polymerase zeta, is involved in translesion synthesis and required for the production of mutations induced by ultraviolet radiation (UV) photoproducts and other DNA fork-blocking lesions, and for the majority of spontaneous mutations. To determine whether hREV3, the human homolog of yeast REV3, is similarly involved in error-prone translesion synthesis past UV photoproducts and other lesions that block DNA replication, an hREV3 antisense construct under the control of the TetP promoter was transfected into an infinite life span human fibroblast cell strain that expresses a high level of tTAk, the activator of that promoter. Three transfectant strains expressing high levels of hREV3 antisense RNA were identified and compared with their parental cell strain for sensitivity to the cytotoxic and mutagenic effects of UV. The three hREV3 antisense-expressing cell strains were not more sensitive than the parental strain to the cytotoxic effect of UV, but the frequency of mutants induced by UV in their HPRT gene was significantly reduced, i.e. to 14% that of the parent. Two of these hREV3 antisense-expressing cell strains were compared with the parental strain for sensitivity to ({+-})-7{beta},8{alpha}-dihydroxy-9{alpha},10{alpha}-epoxy-7,8,9,10-tetrahydro= benzo[a]pyrene (BPDE). They were not more sensitive than the parent strain to the cytotoxic effect of BPDE, but the frequency of mutants induced was significantly reduced, i.e. in one strain, to 17% that of the parent, and in the other, to 24%. DNA sequencing showed that the kinds of mutations induced by BPDE in the parental and the derivative strains did not differ and were similar to those found previously with finite life span human fibroblasts. The data strongly support the hypothesis that hRev3 plays a critical role in the induction of mutations by UV or BPDE. Because the level of hRev3 protein in human fibroblasts is below the level of antibody

  6. hREV3 is essential for error-prone translesion synthesis past UV or benzo[a]pyrene diol epoxide-induced DNA lesions in human fibroblasts

    International Nuclear Information System (INIS)

    Li Ziqiang; Zhang Hong; McManus, Terrence P.; McCormick, J. Justin; Lawrence, Christopher W.; Maher, Veronica M.

    2002-01-01

    In S. cerevisiae, the REV3 gene, encoding the catalytic subunit of polymerase zeta, is involved in translesion synthesis and required for the production of mutations induced by ultraviolet radiation (UV) photoproducts and other DNA fork-blocking lesions, and for the majority of spontaneous mutations. To determine whether hREV3, the human homolog of yeast REV3, is similarly involved in error-prone translesion synthesis past UV photoproducts and other lesions that block DNA replication, an hREV3 antisense construct under the control of the TetP promoter was transfected into an infinite life span human fibroblast cell strain that expresses a high level of tTAk, the activator of that promoter. Three transfectant strains expressing high levels of hREV3 antisense RNA were identified and compared with their parental cell strain for sensitivity to the cytotoxic and mutagenic effects of UV. The three hREV3 antisense-expressing cell strains were not more sensitive than the parental strain to the cytotoxic effect of UV, but the frequency of mutants induced by UV in their HPRT gene was significantly reduced, i.e. to 14% that of the parent. Two of these hREV3 antisense-expressing cell strains were compared with the parental strain for sensitivity to (±)-7β,8α-dihydroxy-9α,10α-epoxy-7,8,9,10-tetrahydrobenzo[a]pyrene (BPDE). They were not more sensitive than the parent strain to the cytotoxic effect of BPDE, but the frequency of mutants induced was significantly reduced, i.e. in one strain, to 17% that of the parent, and in the other, to 24%. DNA sequencing showed that the kinds of mutations induced by BPDE in the parental and the derivative strains did not differ and were similar to those found previously with finite life span human fibroblasts. The data strongly support the hypothesis that hRev3 plays a critical role in the induction of mutations by UV or BPDE. Because the level of hRev3 protein in human fibroblasts is below the level of antibody detection, it was not

  7. Causes and consequences of plant radio-resistance. Formation of DNA basis lesions and self-repairing activity of one of them, the 8-oxo-7,8-dihydro-guanine in Arabidopsis thaliana

    International Nuclear Information System (INIS)

    Dany, A.L.

    2001-01-01

    In this research thesis, the author first explains how and why DNA is injured when it is submitted to an oxidizing stress, and describes precisely the formation and the biological consequences of lesions of DNA bases, the 8-oxo-7,8-dihydro-guanine (8-oxoGua). She describes the repairing activities of the oxidized DNA, and more particularly the repairing of 8-oxoGua, in prokaryotes as well as in yeast, mammals and plants. Methodologies used are described, together with the repair activities of the 8-oxo-7,8-dihydro-guanine following a biochemical type approach and a molecular biology approach

  8. Age and lesion-induced increases of GDNF transgene expression in brain following intracerebral injections of DNA nanoparticles.

    Science.gov (United States)

    Yurek, D M; Hasselrot, U; Cass, W A; Sesenoglu-Laird, O; Padegimas, L; Cooper, M J

    2015-01-22

    In previous studies that used compacted DNA nanoparticles (DNP) to transfect cells in the brain, we observed higher transgene expression in the denervated striatum when compared to transgene expression in the intact striatum. We also observed that long-term transgene expression occurred in astrocytes as well as neurons. Based on these findings, we hypothesized that the higher transgene expression observed in the denervated striatum may be a function of increased gliosis. Several aging studies have also reported an increase of gliosis as a function of normal aging. In this study we used DNPs that encoded for human glial cell line-derived neurotrophic factor (hGDNF) and either a non-specific human polyubiquitin C (UbC) or an astrocyte-specific human glial fibrillary acidic protein (GFAP) promoter. The DNPs were injected intracerebrally into the denervated or intact striatum of young, middle-aged or aged rats, and glial cell line-derived neurotrophic factor (GDNF) transgene expression was subsequently quantified in brain tissue samples. The results of our studies confirmed our earlier finding that transgene expression was higher in the denervated striatum when compared to intact striatum for DNPs incorporating either promoter. In addition, we observed significantly higher transgene expression in the denervated striatum of old rats when compared to young rats following injections of both types of DNPs. Stereological analysis of GFAP+ cells in the striatum confirmed an increase of GFAP+ cells in the denervated striatum when compared to the intact striatum and also an age-related increase; importantly, increases in GFAP+ cells closely matched the increases in GDNF transgene levels. Thus neurodegeneration and aging may lay a foundation that is actually beneficial for this particular type of gene therapy while other gene therapy techniques that target neurons are actually targeting cells that are decreasing as the disease progresses. Copyright © 2014 IBRO. Published by

  9. TFIIH with inactive XPD helicase functions in transcription initiation but is defective in DNA repair

    NARCIS (Netherlands)

    G.S. Winkler (Sebastiaan); U. Fiedler; W. Vermeulen (Wim); F. Coin (Frédéric); R.D. Wood (Richard); H.T.M. Timmers (Marc); G. Weeda (Geert); J.H.J. Hoeijmakers (Jan); S.J. Araú jo; J-M. Egly (Jean-Marc)

    2000-01-01

    textabstractTFIIH is a multisubunit protein complex involved in RNA polymerase II transcription and nucleotide excision repair, which removes a wide variety of DNA lesions including UV-induced photoproducts. Mutations in the DNA-dependent ATPase/helicase subunits of TFIIH, XPB and

  10. Induction and removal of DNA interstrand cross-links in V-79 Chinese hamster cells measured by hydroxylapatite chromatography after treatments with bifunctional furocoumarins

    International Nuclear Information System (INIS)

    Dardalhon, M.; Averbeck, D.

    1988-01-01

    DNA interstrand crosslinks (CL) photoinduced by bifunctional furocoumarins in V-79 Chinese hamster cells were measured by alkaline denaturation and hydroxylapatite chromatography. Treatments with 5-methoxypsoralen (5-MOP), 8-methoxypsoralen (8-MOP) and 4,5',8-trimethylpsoralen (4,5',8-TMP) and 365 nm irradiation (UVA) confer a dose-dependent linear increase in the amount of double-stranded DNA indicating the induction of CL. Determination in alkaline sucrose gradients of the molecular weight of the DNA and estimation of drug-induced strand breakage allowed quantification of the CL induced. 5-MOP was found to be slightly more effective than 8-MOP whereas 4,5',8-TMP was 9 times more effective for the induction of CL. The fate of CL during post-treatment incubation was also followed. Cells in exponential growth phase were found to be efficient in the removal of CL. (Author)

  11. The yield of DNA double strand breaks determined after exclusion of those forming from heat-labile lesions predicts tumor cell radiosensitivity to killing.

    Science.gov (United States)

    Cheng, Yanlei; Li, Fanghua; Mladenov, Emil; Iliakis, George

    2015-09-01

    The radiosensitivity to killing of tumor cells and in-field normal tissue are key determinants of radiotherapy response. In vitro radiosensitivity of tumor- and normal-tissue-derived cells often predicts radiation response, but high determination cost in time and resources compromise utility as routine response-predictor. Efforts to use induction or repair of DNA double-strand-breaks (DSBs) as surrogate-predictors of cell radiosensitivity to killing have met with limited success. Here, we re-visit this issue encouraged by our recent observations that ionizing radiation (IR) induces not only promptly-forming DSBs (prDSBs), but also DSBs developing after irradiation from the conversion to breaks of thermally-labile sugar-lesions (tlDSBs). We employ pulsed-field gel-electrophoresis and flow-cytometry protocols to measure total DSBs (tDSB=prDSB+tlDSBs) and prDSBs, as well as γH2AX and parameters of chromatin structure. We report a fully unexpected and in many ways unprecedented correlation between yield of prDSBs and radiosensitivity to killing in a battery of ten tumor cell lines that is not matched by yields of tDSBs or γH2AX, and cannot be explained by simple parameters of chromatin structure. We propose the introduction of prDSBs-yield as a novel and powerful surrogate-predictor of cell radiosensitivity to killing with potential for clinical application. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

  12. Chemical repair activity of free radical scavenger edaravone. Reduction reactions with dGMP hydroxyl radical adducts and suppression of base lesions and AP sites on irradiated plasmid DNA

    International Nuclear Information System (INIS)

    Hata, Kuniki; Katsumura, Yosuke; Urushibara, Ayumi; Yamashita, Shinichi; Lin Mingzhang; Muroya, Yusa; Shikazono, Naoya; Yokoya, Akinari; Fu Haiying

    2015-01-01

    Reactions of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) with deoxyguanosine monophosphate (dGMP) hydroxyl radical adducts were investigated by pulse radiolysis technique. Edaravone was found to reduce the dGMP hydroxyl radical adducts through electron transfer reactions. The rate constants of the reactions were greater than 4 × 10 8 dm 3 mol -1 s -1 and similar to those of the reactions of ascorbic acid, which is a representative antioxidant. Yields of single-strand breaks, base lesions, and abasic sites produced in pUC18 plasmid DNA by gamma ray irradiation in the presence of low concentrations (10–1000 μmol dm -3 ) of edaravone were also quantified, and the chemical repair activity of edaravone was estimated by a method recently developed by the authors. By comparing suppression efficiencies to the induction of each DNA lesion, it was found that base lesions and abasic sites were suppressed by the chemical repair activity of edaravone, although the suppression of single-strand breaks was not very effective. This phenomenon was attributed to the chemical repair activity of edaravone toward base lesions and abasic sites. However, the chemical repair activity of edaravone for base lesions was lower than that of ascorbic acid. (author)

  13. Chemical repair activity of free radical scavenger edaravone: reduction reactions with dGMP hydroxyl radical adducts and suppression of base lesions and AP sites on irradiated plasmid DNA.

    Science.gov (United States)

    Hata, Kuniki; Urushibara, Ayumi; Yamashita, Shinichi; Lin, Mingzhang; Muroya, Yusa; Shikazono, Naoya; Yokoya, Akinari; Fu, Haiying; Katsumura, Yosuke

    2015-01-01

    Reactions of edaravone (3-methyl-1-phenyl-2-pyrazolin-5-one) with deoxyguanosine monophosphate (dGMP) hydroxyl radical adducts were investigated by pulse radiolysis technique. Edaravone was found to reduce the dGMP hydroxyl radical adducts through electron transfer reactions. The rate constants of the reactions were greater than 4 × 10(8) dm(3) mol(-1) s(-1) and similar to those of the reactions of ascorbic acid, which is a representative antioxidant. Yields of single-strand breaks, base lesions, and abasic sites produced in pUC18 plasmid DNA by gamma ray irradiation in the presence of low concentrations (10-1000 μmol dm(-3)) of edaravone were also quantified, and the chemical repair activity of edaravone was estimated by a method recently developed by the authors. By comparing suppression efficiencies to the induction of each DNA lesion, it was found that base lesions and abasic sites were suppressed by the chemical repair activity of edaravone, although the suppression of single-strand breaks was not very effective. This phenomenon was attributed to the chemical repair activity of edaravone toward base lesions and abasic sites. However, the chemical repair activity of edaravone for base lesions was lower than that of ascorbic acid. © The Author 2014. Published by Oxford University Press on behalf of The Japan Radiation Research Society and Japanese Society for Radiation Oncology.

  14. Analysis of the giant genomes of Fritillaria (Liliaceae) indicates that a lack of DNA removal characterizes extreme expansions in genome size.

    Science.gov (United States)

    Kelly, Laura J; Renny-Byfield, Simon; Pellicer, Jaume; Macas, Jiří; Novák, Petr; Neumann, Pavel; Lysak, Martin A; Day, Peter D; Berger, Madeleine; Fay, Michael F; Nichols, Richard A; Leitch, Andrew R; Leitch, Ilia J

    2015-10-01

    Plants exhibit an extraordinary range of genome sizes, varying by > 2000-fold between the smallest and largest recorded values. In the absence of polyploidy, changes in the amount of repetitive DNA (transposable elements and tandem repeats) are primarily responsible for genome size differences between species. However, there is ongoing debate regarding the relative importance of amplification of repetitive DNA versus its deletion in governing genome size. Using data from 454 sequencing, we analysed the most repetitive fraction of some of the largest known genomes for diploid plant species, from members of Fritillaria. We revealed that genomic expansion has not resulted from the recent massive amplification of just a handful of repeat families, as shown in species with smaller genomes. Instead, the bulk of these immense genomes is composed of highly heterogeneous, relatively low-abundance repeat-derived DNA, supporting a scenario where amplified repeats continually accumulate due to infrequent DNA removal. Our results indicate that a lack of deletion and low turnover of repetitive DNA are major contributors to the evolution of extremely large genomes and show that their size cannot simply be accounted for by the activity of a small number of high-abundance repeat families. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

  15. Managing Carious Lesions

    DEFF Research Database (Denmark)

    Innes, N P T; Frencken, J E; Bjørndal, L

    2016-01-01

    Variation in the terminology used to describe clinical management of carious lesions has contributed to a lack of clarity in the scientific literature and beyond. In this article, the International Caries Consensus Collaboration presents 1) issues around terminology, a scoping review of current...... manifestations to the histopathology, we have based the terminology around the clinical consequences of disease (soft, leathery, firm, and hard dentine). Approaches to carious tissue removal are defined: 1)selective removal of carious tissue-includingselective removal to soft dentineandselective removal to firm...

  16. Processing of free radical damaged DNA bases

    International Nuclear Information System (INIS)

    Wallace, S.

    2003-01-01

    Free radicals produced during the radiolysis of water gives rise to a plethora of DNA damages including single strand breaks, sites of base loss and a wide variety of purine and pyrimidine base lesions. All these damages are processed in cells by base excision repair. The oxidative DNA glycosylases which catalyze the first step in the removal of a base damage during base excision repair evolved primarily to protect the cells from the deleterious mutagenic effects of single free radical-induced DNA lesions arising during oxidative metabolism. This is evidenced by the high spontaneous mutation rate in bacterial mutants lacking the oxidative DNA glycosylases. However, when a low LET photon transverses the DNA molecule, a burst of free radicals is produced during the radiolysis of water that leads to the formation of clustered damages in the DNA molecule, that are recognized by the oxidative DNA glycosylases. When substrates containing two closely opposed sugar damages or base and sugar damages are incubated with the oxidative DNA glycosylases in vitro, one strand is readily incised by the lyase activity of the DNA glycosylase. Whether or not the second strand is incised depends on the distance between the strand break resulting from the incised first strand and the remaining DNA lesion on the other strand. If the lesions are more than two or three base pairs apart, the second strand is readily cleaved by the DNA glycosylase, giving rise to a double strand break. Even if the entire base excision repair system is reconstituted in vitro, whether or not a double strand break ensues depends solely upon the ability of the DNA glycosylase to cleave the second strand. These data predicted that cells deficient in the oxidative DNA glycosylases would be radioresistant while those that overproduce an oxidative DNA glycosylase would be radiosensitive. This prediction was indeed borne in Escherichia coli that is, mutants lacking the oxidative DNA glycosylases are radioresistant

  17. 2,3,7,8-Tetrachlorodibenzo-p-dioxin modulates estradiol-induced aldehydic DNA lesions in human breast cancer cells through alteration of CYP1A1 and CYP1B1 expression.

    Science.gov (United States)

    Chen, Shou-Tung; Chen, Dar-Ren; Fang, Ju-Pin; Lin, Po-Hsiung

    2015-05-01

    Many genes responsible for the bioactivation of endogenous estrogen to reactive quinonoid metabolites, including cytochrome P450 (CYP) 1A1, 1A2, and 1B1, are well-known target genes of the aryl hydrocarbon receptor agonist 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD). The purpose of this research was to investigate the roles of TCDD-mediated altered gene expression in the induction of aldehydic DNA lesions (ADLs) by 17β-estradiol (E2) in human MDA-MB-231 and MCF-7 breast cancer cells. We demonstrated that increases in the number of oxidant-mediated ADLs, including abasic sites and aldehydic base/sugar lesions, were detected in MDA-MB-231 cells exposed to E2. The DNA-damaging effects of E2 in MDA-MB-231 cells were prevented by pretreatment of cells with TCDD. In contrast, we did not observe statistically significant increases in the number of ADLs in MCF-7 cells exposed to E2. However, with TCDD pretreatment, an approximately twofold increase in the number of ADLs was detected in MCF-7 cells exposed to E2. TCDD pretreatment induces disparity in the disposition of E2 to reactive quinonoid metabolites and the subsequent formation of oxidative DNA lesions through alteration of CYP1A1 and CYP1B1 expression in human breast cancer cells.

  18. Misrepair of overlapping daughter strand gaps as a possible mechanism for UV induced mutagenesis in uvr strains of Escherichia coli: a general model for induced mutagenesis by misrepair (SOS repair) of closely spaced DNA lesions

    International Nuclear Information System (INIS)

    Sedgwick, S.G.

    1976-01-01

    It has been previously reported that an inducible form of post-replication repair appeared to be required for UV induced mutagenesis in an uvrA strain of Escherichia coli. It is shown here that the numbers of daughter strand gaps requiring inducible repair were similar to the numbers calculated to be overlapping one another in opposite daughter chromosomes. An estimation of survival with no repair of these gaps resembled the survival predicted with mutagenesis. It is thus proposed that inducible post-replication repair causes mutagenesis by the repair of overlapping daughter strand gaps. A general model for induced mutagenesis is presented. It is proposed that (a) some DNA lesions introduced by any DNA damaging agent may be close enough to interfere with constitutive repair replication of each other, (b) these lesions induce a repair system (SOS repair) which involves the recA + . lexA + and polC + genes (c) repair, and noncomitant mutagenesis occurs during repair replication by the insertion of mismatched bases oppposite the noncoding DNA lesions

  19. Genome instabilities arising from ribonucleotides in DNA.

    Science.gov (United States)

    Klein, Hannah L

    2017-08-01

    Genomic DNA is transiently contaminated with ribonucleotide residues during the process of DNA replication through misincorporation by the replicative DNA polymerases α, δ and ε, and by the normal replication process on the lagging strand, which uses RNA primers. These ribonucleotides are efficiently removed during replication by RNase H enzymes and the lagging strand synthesis machinery. However, when ribonucleotides remain in DNA they can distort the DNA helix, affect machineries for DNA replication, transcription and repair, and can stimulate genomic instabilities which are manifest as increased mutation, recombination and chromosome alterations. The genomic instabilities associated with embedded ribonucleotides are considered here, along with a discussion of the origin of the lesions that stimulate particular classes of instabilities. Copyright © 2017 Elsevier B.V. All rights reserved.

  20. Coordinating repair of oxidative DNA damage with transcription and replication

    International Nuclear Information System (INIS)

    Cooper, P.K.

    2003-01-01

    Transcription-coupled repair (TCR) preferentially removes DNA lesions from template strands of active genes. Defects in TCR, which acts both on lesions removed by nucleotide excision repair (NER) and on oxidative lesions removed by base excision repair (BER), underlie the fatal developmental disorder Cockayne syndrome. Although its detailed mechanism remains unknown, TCR involves recognition of a stalled RNA polymerase (RNAP), removal or remodeling of RNAP to allow access to the lesion, and recruitment of repair enzymes. At a minimum, these early steps require a non-enzymatic function of the multifunctional repair protein XPG, the CSB protein with ATP-dependent chromatin remodeling activity, and the TFIIH complex (including the XPB and XPD helicases) that is also required for basal transcription initiation and NER. XPG exists in the cell in a complex with TFIIH, and in vitro evidence has suggested that it interacts with CSB. To address the mechanism of TCR, we are characterizing protein-DNA and protein-protein interactions of XPG. We show that XPG preferentially binds to double-stranded DNA containing bubbles resembling in size the unpaired regions associated with transcription. Two distinct domains of XPG are required for the observed strong binding specificity and stability. XPG both interacts directly with CSB and synergistically binds with it to bubble DNA, and it strongly stimulates the bubble DNA-dependent ATPase activity of CSB. Significantly for TCR, XPG also interacts directly with RNAP II, binds both the protein and nucleic acid components (the R-loop) of a stalled RNA polymerase, and forms a ternary complex with CSB and the stalled RNAP. These results are consistent with the model that XPG and CSB jointly interact with the DNA/chromatin structure in the vicinity of the stalled transcriptional apparatus and with the transcriptional machinery itself to remodel the chromatin and either move or remodel the blocked RNA polymerase to expose the lesion

  1. The Effectiveness of the Removal of DNA from the Surfaces of EVA-Based Mouthguards using Standard Cleaning Protocols

    Science.gov (United States)

    2016-06-16

    true due to the fact that mouth guards are often used by athletes and military personnel in outdoor settings and given the fact that soil microbes...contact, DNA is transferred from plasmids or transposons. The genetic material transferred is often beneficial to the recipient with possible benefits of...oral injuries. J Am Dent Assoc 2006;137(12):1712-20. 3. Center for Science information, ADA Science Institute, ADA.org/oral health topics/. November

  2. Comparison of the diagnostic value of cervical cytology and HPV HR DNA testing for the diagnosis of low-grade and high-grade squamous intraepithelial lesions across different age groups.

    Science.gov (United States)

    Paluszkiewicz, Aleksandra; Pruski, Dominik; Iwaniec, Kinga; Kędzia, Witold

    2017-01-01

    To assess the diagnostic value of cervical cytology and HPV HR DNA testing for the diagnosis of low grade and high-grade squamous intraepithelial lesions across different age groups. The study included 1103 patients, age 25-70 years. All patients underwent in-depth diagnostic tests following either an abnormal Pap test result or a clinically suspicious cervical lesion. In all women the following examinations were performed: a molecular test detecting 14 high-risk types of HPV, a colposcopy examination, as well as directed-biopsy of the cervix. The studied population was subdivided into four age groups. It was observed that the percentage of high grade squamous intraepithelial lesions (HSIL) and cancers increased with women's age. Sensitivity of both methods for detecting high-grade squamous intraepithelial lesions was highest for women aged 40-49 years. Sensitivity values of HPV testing was higher than that of cervical cytology among women under age 50. Specificity of HPV testing increased significantly with age of women and was several fold higher across all age groups than the specificity of cervical cytology.

  3. Rad10 exhibits lesion-dependent genetic requirements for recruitment to DNA double-strand breaks in Saccharomyces cerevisiae

    DEFF Research Database (Denmark)

    Moore, Destaye M; Karlin, Justin; González-Barrera, Sergio

    2009-01-01

    In the yeast Saccharomyces cerevisiae, the Rad1-Rad10 protein complex participates in nucleotide excision repair (NER) and homologous recombination (HR). During HR, the Rad1-Rad10 endonuclease cleaves 3' branches of DNA and aberrant 3' DNA ends that are refractory to other 3' processing enzymes. ...

  4. DNA Damage Response and Immune Defence: Links and Mechanisms

    Directory of Open Access Journals (Sweden)

    Björn Schumacher

    2016-08-01

    Full Text Available DNA damage plays a causal role in numerous human pathologies including cancer, premature aging and chronic inflammatory conditions. In response to genotoxic insults, the DNA damage response (DDR orchestrates DNA damage checkpoint activation and facilitates the removal of DNA lesions. The DDR can also arouse the immune system by for example inducing the expression of antimicrobial peptides as well as ligands for receptors found on immune cells. The activation of immune signalling is triggered by different components of the DDR including DNA damage sensors, transducer kinases, and effectors. In this review, we describe recent advances on the understanding of the role of DDR in activating immune signalling. We highlight evidence gained into (i which molecular and cellular pathways of DDR activate immune signalling, (ii how DNA damage drives chronic inflammation, and (iii how chronic inflammation causes DNA damage and pathology in humans.

  5. A promising split-lesion technique for rapid tattoo removal using a novel sequential approach of a single sitting of pulsed CO(2) followed by Q-switched Nd: YAG laser (1064 nm).

    Science.gov (United States)

    Sardana, Kabir; Garg, Vijay K; Bansal, Shivani; Goel, Khushbu

    2013-12-01

    Laser tattoo removal conventionally uses Q-switched (QS) lasers, but they require multiple sittings, and the end results depend largely on the type of tattoo treated. In pigmented skin, due to the competing epidermal pigment results, laser results in tattoo are slow and inadequate. To evaluate the efficacy of a combined use of ultrapulse CO2 and QS Nd:YAG (1064 nm) laser in the treatment of tattoos in Indian skin. A split-lesion trial was carried out in five patients, with the left side of tattoos receiving the QS Nd:YAG (1064 nm) and the right side, a sequential combination of Up CO2 and QS Nd: YAG at 6 weeks interval with a maximum of six sittings. Outcome assessment was carried out by a blinded assessor using standardized photography. An assessment of physician improvement score, side-effects score, and patient satisfaction score was taken during and at the end of the study. There was a statistically significant improvement on the combination side(physician improvement score -3.7 vs. 1.87: P = 0.0019) which occurred earlier with fewer sittings (1.7 vs. 6). There was no statistically significant difference in the side effects. A combination of an Up CO2 laser with QS Nd: YAG laser is a promising tool for rapid and effective removal of blue-black/blue amateur tattoo in pigmented skin. © 2013 Wiley Periodicals, Inc.

  6. Protocol for quality control in radio guided surgery procedures for detection and removal of sentinel node and non palpable lesions; Protocolo de control de calidad para procedimientos de cirugia radioguiada para deteccion y extirpacion de ganglio centinela y de lesiones no palpables

    Energy Technology Data Exchange (ETDEWEB)

    Prieto Moran, D.; Sanchez Noriega, K.; Rodriguez Meijide, P.

    2015-05-01

    In this work the process for the detection and/or removal of the sentinel lymph node and nonpalpable lesions has been optimized. For the latter, a {sup 1}25 I, seed an isotope that is not usually used for this purpose, is employed. It was recycled from radiotherapy treatments surpluses, having requested the necessary authorizations. A detailed procedure for the management, storage, transport and sterilization of the {sup 1}25 I seed in the hospital has been developed. A custom protocol has been defined for quality control of intraoperative probes with different tests, providing methods, frequencies, tolerances, etc. The overall result is an improvement of the process and a decrease of the inconveniences for the patient. (Author)

  7. Molecular analysis by electron microscopy of the removal of psoralen-photoinduced DNA cross-links in normal and Fanconi's anemia fibroblasts

    International Nuclear Information System (INIS)

    Rousset, S.; Nocentini, S.; Revet, B.; Moustacchi, E.

    1990-01-01

    The induction and fate of psoralen-photoinduced DNA interstrand cross-links in the genome of Fanconi's anemia (FA) fibroblasts of complementation groups A and B, and of normal human fibroblasts, were investigated by quantitative analysis of totally denatured DNA fragments visualized by electron microscopy. 8-Methoxypsoralen (5 x 10(-5) M) interstrand cross-links were induced as a function of the near ultraviolet light dose. With time of postexposure incubation, a fraction of interstrand cross-links disappeared in all cell lines. However, 24 h after treatment, this removal was significantly lower in the two FA group A cell lines examined (34-39%) than in the FA group B and normal cell lines (43-53 and 47-57%, respectively). These data indicate that FA cells are at least able to recognize and incise interstrand cross-links, as normal cells do, although group A cells seem somewhat hampered in this process. This is in accord with data obtained on the same cell lines using another biochemical assay. Since the fate of cross-links in FA constituted a controversial matter, it is important to stress that two different methodologies applied to genetically well defined cell lines led to the same conclusions

  8. In vivo repair of methylation damage in Aag 3-methyladenine DNA glycosylase null mouse cells

    OpenAIRE

    Smith, Stephen A.; Engelward, Bevin P.

    2000-01-01

    3-Methyladenine (3MeA) DNA glycosylases initiate base excision repair by removing 3MeA. These glycosylases also remove a broad spectrum of spontaneous and environmentally induced base lesions in vitro. Mouse cells lacking the Aag 3MeA DNA glycosylase (also known as the Mpg, APNG or ANPG DNA glycosylase) are susceptible to 3MeA-induced S phase arrest, chromosome aberrations and apoptosis, but it is not known if Aag is solely responsible for repair of 3MeA in vivo. Here we show that in Aag–/– c...

  9. DNA Mismatch Repair and Oxidative DNA Damage: Implications for Cancer Biology and Treatment

    International Nuclear Information System (INIS)

    Bridge, Gemma; Rashid, Sukaina; Martin, Sarah A.

    2014-01-01

    Many components of the cell, including lipids, proteins and both nuclear and mitochondrial DNA, are vulnerable to deleterious modifications caused by reactive oxygen species. If not repaired, oxidative DNA damage can lead to disease-causing mutations, such as in cancer. Base excision repair and nucleotide excision repair are the two DNA repair pathways believed to orchestrate the removal of oxidative lesions. However, recent findings suggest that the mismatch repair pathway may also be important for the response to oxidative DNA damage. This is particularly relevant in cancer where mismatch repair genes are frequently mutated or epigenetically silenced. In this review we explore how the regulation of oxidative DNA damage by mismatch repair proteins may impact on carcinogenesis. We discuss recent studies that identify potential new treatments for mismatch repair deficient tumours, which exploit this non-canonical role of mismatch repair using synthetic lethal targeting

  10. DNA Mismatch Repair and Oxidative DNA Damage: Implications for Cancer Biology and Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Bridge, Gemma; Rashid, Sukaina; Martin, Sarah A., E-mail: sarah.martin@qmul.ac.uk [Centre for Molecular Oncology, Barts Cancer Institute, Queen Mary University of London, Charterhouse Square, London EC1M 6BQ (United Kingdom)

    2014-08-05

    Many components of the cell, including lipids, proteins and both nuclear and mitochondrial DNA, are vulnerable to deleterious modifications caused by reactive oxygen species. If not repaired, oxidative DNA damage can lead to disease-causing mutations, such as in cancer. Base excision repair and nucleotide excision repair are the two DNA repair pathways believed to orchestrate the removal of oxidative lesions. However, recent findings suggest that the mismatch repair pathway may also be important for the response to oxidative DNA damage. This is particularly relevant in cancer where mismatch repair genes are frequently mutated or epigenetically silenced. In this review we explore how the regulation of oxidative DNA damage by mismatch repair proteins may impact on carcinogenesis. We discuss recent studies that identify potential new treatments for mismatch repair deficient tumours, which exploit this non-canonical role of mismatch repair using synthetic lethal targeting.

  11. Analysis of damaged DNA / proteins interactions: Methodological optimizations and applications to DNA lesions induced by platinum anticancer drugs; Analyse des interactions ADN lese / proteines: Optimisations methodologiques et applications aux dommages de l'ADN engendres par les derives du platine

    Energy Technology Data Exchange (ETDEWEB)

    Bounaix Morand du Puch, Ch

    2010-10-15

    DNA lesions contribute to the alteration of DNA structure, thereby inhibiting essential cellular processes. Such alterations may be beneficial for chemotherapies, for example in the case of platinum anticancer agents. They generate bulky adducts that, if not repaired, ultimately cause apoptosis. A better understanding of the biological response to such molecules can be obtained through the study of proteins that directly interact with the damages. These proteins constitute the DNA lesions interactome. This thesis presents the development of tools aiming at increasing the list of platinum adduct-associated proteins. Firstly, we designed a ligand fishing system made of damaged plasmids immobilized onto magnetic beads. Three platinum drugs were selected for our study: cisplatin, oxali-platin and satra-platin. Following exposure of the trap to nuclear extracts from HeLa cancer cells and identification of retained proteins by proteomics, we obtained already known candidates (HMGB1, hUBF, FACT complex) but also 29 new members of the platinated-DNA interactome. Among them, we noted the presence of PNUTS, TOX4 and WDR82, which associate to form the recently-discovered PTW/PP complex. Their capture was then confirmed with a second model, namely breast cancer cell line MDA MB 231, and the biological consequences of such an interaction now need to be elucidated. Secondly, we adapted a SPRi bio-chip to the study of platinum-damaged DNA/proteins interactions. Affinity of HMGB1 and newly characterized TOX4 for adducts generated by our three platinum drugs could be validated thanks to the bio-chip. Finally, we used our tools, as well as analytical chemistry and biochemistry methods, to evaluate the role of DDB2 (a factor involved in the recognition of UV-induced lesions) in the repair of cisplatin adducts. Our experiments using MDA MB 231 cells differentially expressing DDB2 showed that this protein is not responsible for the repair of platinum damages. Instead, it appears to act

  12. Circulating mitochondrial DNA as biomarker linking environmental chemical exposure to early preclinical lesions elevation of mtDNA in human serum after exposure to carcinogenic halo-alkane-based pesticides.

    Directory of Open Access Journals (Sweden)

    Lygia T Budnik

    Full Text Available There is a need for a panel of suitable biomarkers for detection of environmental chemical exposure leading to the initiation or progression of degenerative diseases or potentially, to cancer. As the peripheral blood may contain increased levels of circulating cell-free DNA in diseased individuals, we aimed to evaluate this DNA as effect biomarker recognizing vulnerability after exposure to environmental chemicals. We recruited 164 individuals presumably exposed to halo-alkane-based pesticides. Exposure evaluation was based on human biomonitoring analysis; as biomarker of exposure parent halo-methanes, -ethanes and their metabolites, as well as the hemoglobin-adducts methyl valine and hydroxyl ethyl valine in blood were used, complemented by expert evaluation of exposure and clinical intoxication symptoms as well as a questionnaire. Assessment showed exposures to halo alkanes in the concentration range being higher than non-cancer reference doses (RfD but (mostly lower than the occupational exposure limits. We quantified circulating DNA in serum from 86 individuals with confirmed exposure to off-gassing halo-alkane pesticides (in storage facilities or in home environment and 30 non-exposed controls, and found that exposure was significantly associated with elevated serum levels of circulating mitochondrial DNA (in size of 79 bp, mtDNA-79, p = 0.0001. The decreased integrity of mtDNA (mtDNA-230/mtDNA-79 in exposed individuals implicates apoptotic processes (p = 0.015. The relative amounts of mtDNA-79 in serum were positively associated with the lag-time after intoxication to these chemicals (r = 0.99, p<0.0001. Several months of post-exposure the specificity of this biomarker increased from 30% to 97% in patients with intoxication symptoms. Our findings indicate that mitochondrial DNA has a potential to serve as a biomarker recognizing vulnerable risk groups after exposure to toxic/carcinogenic chemicals.

  13. Relationship between DNA replication and DNA repair in human lymphocytes proliferating in vitro in the presence and in absence of mutagen

    International Nuclear Information System (INIS)

    Szyfter, K.; Wielgosz, M.Sz.; Kujawski, M.; Jaloszynski, P.; Zajaczek, S.

    1995-01-01

    The effects of mutagens on DNA replication and DNA repair were studied in peripheral blood lymphocytes (PBL) obtained from 21 healthy subjects, 2 samples from healthy heterozygote of ''Xeroderma pigmentosum'' (XP) and 2 samples from patient with clinically recognised XP. Inter-individual variations were found in DNA replication and in the level of spontaneous DNA repair measured under standard culture condition. Exposure of human PBL proliferating in vitro to B(a)P was followed by a partial inhibition of replicative DNA synthesis in all subjects and by an induction of DNA repair in healthy subjects. In XP patients DNA repair synthesis remained at the level attributed to spontaneous DNA repair. The response to mutagen varied individually. Results were analysed statistically. It was established that the studied indices of DNA synthesis correlate well with each other. The highest correlation was found between the levels of spontaneous and B(a)P-induced DNA repair. It is concluded that the level of spontaneous DNA repair is predictive for an estimation of cells ability to repair DNA damage. Inter-individual variations in the inhibition of DNA replication and in DNA repair synthesis are also dependent on the type of mutagen as shown by effects of other mutagens. Different effects of mutagen exposure on the inhibition of DNA replicative synthesis and induction of DNA repair can be explained by genetically controlled differences in the activity of enzymes responsible for mutagen processing and lesion removal. (author). 37 refs, 2 figs, 2 tabs

  14. Repair of DNA lesions induced by ultraviolet irradiation and aromatic amines in normal and repair-deficient human lymphoblastoid cell lines

    DEFF Research Database (Denmark)

    Stevnsner, Tinna; Frandsen, Henrik; Autrup, Herman

    1995-01-01

    (AAF) respectively. The cell line belonging to xeroderma pigmentosum complementation group C (XP-C) removed all three types of damage less efficiently than the normal cell line, but more efficiently than the cell line belonging to xeroderma pigmentosum complementation group D (XP-D). The cell line...

  15. AN UPWARD TREND IN DNA P16INK4A METHYLATION PATTERN AND HIGH RISK HPV INFECTION ACCORDING TO THE SEVERITY OF THE CERVICAL LESION

    Directory of Open Access Journals (Sweden)

    Fernanda Nahoum Carestiato

    2013-09-01

    Full Text Available SUMMARY High-risk human papillomavirus (hr-HPV infection is necessary but not sufficient for cervical cancer development. Recently, P16INK4A gene silencing through hypermethylation has been proposed as an important cofactor in cervical carcinogenesis due to its tumor suppressor function. We aimed to investigate P16INK4A methylation status in normal and neoplastic epithelia and evaluate an association with HPV infection and genotype. This cross-sectional study was performed with 141 cervical samples from patients attending Hospital Moncorvo Filho, Rio de Janeiro. HPV detection and genotyping were performed through PCR and P16INK4A methylation by nested-methylation specific PCR (MSP. HPV frequency was 62.4% (88/141. The most common HPV were HPV16 (37%, HPV18 (16.3% and HPV33/45(15.2%. An upward trend was observed concerning P16INK4A methylation and lesion degree: normal epithelia (10.7%, low grade lesions (22.9%, high grade (57.1% and carcinoma (93.1% (p < 0.0001. A multivariate analysis was performed to evaluate an association between methylation, age, tobacco exposure, HPV infection and genotyping. A correlation was found concerning methylation with HPV infection (p < 0.0001, hr-HPV (p = 0.01, HSIL (p < 0.0007 and malignant lesions (p < 0.0001. Since viral infection and epigenetic alterations are related to cervical carcinoma, we suggest that P16INK4A methylation profile maybe thoroughly investigated as a biomarker to identify patients at risk of cancer.

  16. Comparison of Onclarity Human Papillomavirus (HPV) Assay with Hybrid Capture II HPV DNA Assay for Detection of Cervical Intraepithelial Neoplasia Grade 2 and 3 Lesions

    DEFF Research Database (Denmark)

    Bottari, F; Sideri, M; Gulmini, C

    2015-01-01

    and negative HC2 results, were prospectively enrolled for the study. The overall agreement between Onclarity and HC2 was 94.6% (95% confidence intervals [CI], 92.3% to 96.2%). In this population with a high prevalence of disease, the relative sensitivities (versus adjudicated cervical intraepithelial neoplasia......, to concurrent cytology and histology results, in order to evaluate its performance in detecting high-grade cervical lesions. A population of 567 women, including 325 with ≥ASCUS (where ASCUS stands for atypical cells of undetermined significance) and any HC2 result and 242 with both negative cytology...

  17. RFWD3-Mediated Ubiquitination Promotes Timely Removal of Both RPA and RAD51 from DNA Damage Sites to Facilitate Homologous Recombination.

    Science.gov (United States)

    Inano, Shojiro; Sato, Koichi; Katsuki, Yoko; Kobayashi, Wataru; Tanaka, Hiroki; Nakajima, Kazuhiro; Nakada, Shinichiro; Miyoshi, Hiroyuki; Knies, Kerstin; Takaori-Kondo, Akifumi; Schindler, Detlev; Ishiai, Masamichi; Kurumizaka, Hitoshi; Takata, Minoru

    2017-06-01

    RFWD3 is a recently identified Fanconi anemia protein FANCW whose E3 ligase activity toward RPA is essential in homologous recombination (HR) repair. However, how RPA ubiquitination promotes HR remained unknown. Here, we identified RAD51, the central HR protein, as another target of RFWD3. We show that RFWD3 polyubiquitinates both RPA and RAD51 in vitro and in vivo. Phosphorylation by ATR and ATM kinases is required for this activity in vivo. RFWD3 inhibits persistent mitomycin C (MMC)-induced RAD51 and RPA foci by promoting VCP/p97-mediated protein dynamics and subsequent degradation. Furthermore, MMC-induced chromatin loading of MCM8 and RAD54 is defective in cells with inactivated RFWD3 or expressing a ubiquitination-deficient mutant RAD51. Collectively, our data reveal a mechanism that facilitates timely removal of RPA and RAD51 from DNA damage sites, which is crucial for progression to the late-phase HR and suppression of the FA phenotype. Copyright © 2017 Elsevier Inc. All rights reserved.

  18. Direct assays of radiation-induced DNA base lesions in mammalian cells: Technical progress report, July 1, 1986--December 1, 1988

    International Nuclear Information System (INIS)

    Wheeler, K.T. Jr.

    1988-01-01

    Our cesium irradiator was installed in April 1987 and has the capability of irradiating DNA solutions, cells and animals at dose rates from >60 Gy/min to <10/sup /minus/2/ Gy/min. By early summer all of the dosimetry and set-ups were established to perform this research. In may 1987, Dr. Krystyna Lesiak left to return to the National Institutes of Health. However, she has remained a collaborator over the past 1/1/2/ years. She has synthesized a large lot of α-deoxyadenosine, isolated a large batch of both the R and S isomer of cyclodeoxyadenosine and has capped the α-deoxyadenonsine for use in a DNA synthesizer that uses phosphoramidite chemistry. In November 1987, Dr. Andrzej Surowiec joined our unit as a Visiting Research Assistant Professor. Dr. Surowiec has a MS degree in electrical engineering and did his Ph.D. in Biophysics studying the conductivity of DNA in dilute solution. He has been performing the helix-coil transition experiments. In November 1987, Dr. Steven Swarts also joined our unit as a Postdoctoral Fellow. He received his Ph.D. from Oakland University under Dr. Michael Sevilla with whom we have a collaboration studying the induction of base damage in hydrated DNA. Dr. Swarts has a strong background in spectroscopy and, therefore, was a key individual for determination of the limitations of the HPLC assays and the establishment of a GC/MS capability equivalent to Dr. M. Dizdaroglu at the National Bureau of Standards. 9 refs., 1 tab

  19. (UVB)-induced DNA damage

    African Journals Online (AJOL)

    Jane

    2011-08-17

    dependent cytogenetic lesions were assessed by the micronucleus test (MNT). It was found that POE effectively reduced the extent of DNA breakages and cytogenetic lesions upon exposure to UVB (erythemal ultraviolet (EUV);.

  20. Human papillomavirus in oral lesions Virus papiloma humano en lesiones orales

    OpenAIRE

    Joaquín V. Gónzalez; Rafael A. Gutiérrez; Alicia Keszler; Maria Del Carmen Colacino; Lidia V. Alonio; Angélica R. Teyssie; Maria Alejandra Picconi

    2007-01-01

    Growing evidence suggests a role for human papillomavirus (HPV) in oral cancer; however its involvement is still controversial. This study evaluates the frequency of HPV DNA in a variety of oral lesions in patients from Argentina. A total of 77 oral tissue samples from 66 patients were selected (cases); the clinical-histopathological diagnoses corresponded to: 11 HPV- associated benign lesions, 8 non-HPV associated benign lesions, 33 premalignant lesions and 25 cancers. Sixty exfoliated cell ...

  1. O6-ethylguanine carcinogenic lesions in DNA: An NMR study of O6etG·T pairing in dodecanucloetide duplexes

    International Nuclear Information System (INIS)

    Kalnik, M.W.; Li, B.F.L.; Swann, P.F.; Patel, D.J.

    1989-01-01

    High-resolution two-dimensional NMR studies are reported on the self-complementary d-(C1-G2-C3-O 6 etG4-A5-G6-C7-T8-T9-G10-C11-G12) duplex (designated O 6 etG·T 12-mer) containing two symmetrically related O 6 etG·T lesion sites located four base pairs in from either end of the duplex. Parallel studies were undertaken on a related sequence containing O 6 meG·T lesion sites (designated O 6 meG·T 12-mer) in order to evaluate the influence of the size of the alkyl substituent on the structure of the duplex and were undertaken on a related sequence containing G·T mismatch sites (designated G·T 12-mer duplex), which served as the control duplex. The exchangeable and nonexchangeable proton and the phosphorus nuclei have been assigned from an analysis of two-dimensional nuclear Overhauser enhancement (NOE) and correlated spectra of the O 6 etG·T 12-mer, O 6 meG·T 12-mer, and G·T 12-mer duplexes in H 2 O and D 2 O solutions. The distance connectivities observed in the NOESY spectra of the O 6 alkG·T 12-mer duplexes establish that the helix is right-handed and all of the bases adopt an anti conformation of the glycosidic torsion angle including the O 6 alkG4 and T9 bases at the lesion site. These observations establish that the O 6 alkG4 and T9 residues are stacked into the duplex and that the O 6 CH 3 and O 6 CH 2 CH 3 groups of O 6 alkG4 adopt a syn orientation with respect to the N 1 of the alkylated guanine. Since the O 6 -alkyl group adopts a syn orientation, the separation between the O 6 of O 6 alkG4 and the O 4 of T9 in the major groove is increased, preventing the formation of a short hydrogen bond between the N 1 ring nitrogen of O 6 alkG4 and the imino proton of T9

  2. ATR-Chk1-APC/C-dependent stabilization of Cdc7-ASK (Dbf4) kinase is required for DNA lesion bypass under replication stress

    DEFF Research Database (Denmark)

    Yamada, M.; Watanabe, K.; Mistrik, M.

    2013-01-01

    replication. Stalled DNA replication evoked stabilization of the Cdc7-ASK (Dbf4) complex in a manner dependent on ATR-Chk1-mediated checkpoint signaling and its interplay with the anaphase-promoting complex/cyclosomeCdh1 (APC/C) ubiquitin ligase. Mechanistically, Chk1 kinase inactivates APC/C through...... degradation of Cdh1 upon replication block, thereby stabilizing APC/C substrates, including Cdc7-ASK (Dbf4). Furthermore, motif C of ASK (Dbf4) interacts with the N-terminal region of RAD18 ubiquitin ligase, and this interaction is required for chromatin binding of RAD18. Impaired interaction of ASK (Dbf4...

  3. A new sensitive 32P-postlabeling assay based on the specific enzymatic conversion of bulky DNA lesions to radiolabeled dinucleotides and nucleoside 5'-monophosphates

    International Nuclear Information System (INIS)

    Randerath, Kurt; Randerath, Erika; Danna, T.F.; Van Golen, K.L.; Putman, K.L.

    1989-01-01

    A new sensitive 32 P-postlabelling assay for DNA adducts has been developed. When DNA containing bulky adducts, X 1 , X 2 , .....X n , is digested with nuclease P1 at pH 5, normal nucleotides are released as 5'-monophosphates, pN, while adducts are excised as 5'-phosphorylated dinucleotides, pX i pN, because inter-nucleotide linkages on the 3' side of X resist attack by nuclease P1. Addition of prostatic acid phosphatase to such a digest results in 5'-dephosphorylation of the nucleotides to normal nucleosides, N, and adducted dinucleotides, X i pN, carrying a 5'-terminal free hydroxyl group. The dinucleotides but not nucleosides are converted to 5'- 32 P-labeled dinucleotides,[ 32 P]pX i pN, by T4 polynucleotide kinase-catalyzed [ 32 P]posphate transfer from [γ- 32 P]ATP. Upon mapping on polyethyleneimine-cellulose anion-exchange TLC, the labeled dinucleotide adducts produce characteristic autoradiographic fingerprints. Alternatively, they are further digested with snake venom phosphodiesterase to yield 5'-monophosphates, [ 32 P]pX i and pN. TLC profiles of the monophosphate adducts are distinct from those of the dinucleotides. These reactions provide the basis of the new 32 P-postlabeling scheme, which is compared in this paper with a previously reported protocol yielding adducts in the form of 5'- 32 P-labeled 3',5'-bisphosphates, [ 32 P]pX i p. (author)

  4. O6-ethylguanine carcinogenic lesions in DNA: An NMR study of O6etG·C pairing in dodecanucleotide duplexes

    International Nuclear Information System (INIS)

    Kalnik, M.W.; Li, B.F.L.; Swann, P.F.; Patel, D.J.

    1989-01-01

    The pairing of O 6 etG with C located four base pairs in from either end of the self-complementary d(C1-G2-C3-O 6 etG4-A5-G6-C7-T8-C9-G10-C11-G12) duplex (designated O 6 etG·C 12-mer) has been investigated from an analysis of proton and phosphorus two-dimensional NMR experiments. The structural consequences of increasing the alkyl group size were elucidated from a comparative study of the pairing of O 6 meG4 with C9 in a related sequence (designated O 6 meG·C 12-mer). The NMR parameters for both O 6 alkG-containing dodecanucleotides are also compared with those of the control sequence containing G4·C9 base pairs (designated G·C 12-mer). The NOE cross-peaks detected in the two-dimensional NOESY spectra of the O 6 alkG·C 12-mer duplexes in H 2 O solution establish that the O 6 etG4/O 6 meG4 and C9 bases at the lesion site stack into the helix between the flanking C3·G10 and A5·T8 Watson-Crick base pairs. The observed NOEs between the amino protons of C9 and the CH 3 protons of O 6 alkG4 establish a syn orientation of the O 6 -alkyl group with respect to the N 1 of alkylated guanine. A wobble alignment of the O 6 alkG4·C9 base pair stabilized by two hydrogen bonds, one between the amino group of C9 and N 1 of O 6 alkG and the other between the amino group of O 6 alkG and N 3 of C9, is tentatively proposed on the basis of the NOEs between the amino protons of C9 at the lesion site and the imino protons of flanking Watson-Crick base pairs

  5. EWS Knockdown and Taxifolin Treatment Induced Differentiation and Removed DNA Methylation from p53 Promoter to Promote Expression of Puma and Noxa for Apoptosis in Ewing's Sarcoma.

    Science.gov (United States)

    Hossain, Mohammad Motarab; Ray, Swapan Kumar

    2014-10-01

    Ewing's sarcoma is a pediatric tumor that mainly occurs in soft tissues and bones. Malignant characteristics of Ewing's sarcoma are correlated with expression of EWS oncogene. We achieved knockdown of EWS expression using a plasmid vector encoding EWS short hairpin RNA (shRNA) to increase anti-tumor mechanisms of taxifolin (TFL), a new flavonoid, in human Ewing's sarcoma cells in culture and animal models. Immunofluorescence microscopy and flow cytometric analysis showed high expression of EWS in human Ewing's sarcoma SK-N-MC and RD-ES cell lines. EWS shRNA plus TFL inhibited 80% cell viability and caused the highest decreases in EWS expression at mRNA and protein levels in both cell lines. Knockdown of EWS expression induced morphological features of differentiation. EWS shRNA plus TFL caused more alterations in molecular markers of differentiation than either agent alone. EWS shRNA plus TFL caused the highest decreases in cell migration with inhibition of survival, angiogenic and invasive factors. Knockdown of EWS expression was associated with removal of DNA methylation from p53 promoter, promoting expression of p53, Puma, and Noxa. EWS shRNA plus TFL induced the highest amounts of apoptosis with activation of extrinsic and intrinsic pathways in both cell lines in culture. EWS shRNA plus TFL also inhibited growth of Ewing's sarcoma tumors in animal models due to inhibition of differentiation inhibitors and angiogenic and invasive factors and also induction of activation of caspase-3 for apoptosis. Collectively, knockdown of EWS expression increased various anti-tumor mechanisms of TFL in human Ewing's sarcoma in cell culture and animal models.

  6. [Direct assays of radiation-induced DNA base lesions in mammalian cells.] Final progress report, February 1, 1984-June 30, 1986

    International Nuclear Information System (INIS)

    Wheeler, K.T.

    1986-01-01

    Adenine (Ade), 2'-deoxyadenosine (dAdo) and 5'-deoxyadenosine monophosphate (5'-dAMP) were irradiated with 50 to 15,000 Gy under oxic and hypoxic conditions. HPLC procedures providing satisfactory separation of the adenine damage products formed during irradiation of DNA model compounds were found. Structures of some of the damage products were confirmed to include 8-OHAde, 4,6-diamino-5-formamidopyrimidine, and 8-OH-5'-dAMP. Two damage products of dAdo (8-OHdAdo and the major isomer of 8,5'-cdAdo), the formation of which depends on the presence or absence of oxygen, were determined quantitatively by HPLC. The limit for HPLC detection was estimated as 4 to 50 pmoles for these compounds. This corresponds to a detection limit of about 50 Gy in radiation dose units. These two products were also detected in mixtures of all four nucleosides irradiated with 50 Gy

  7. DNA damage mediated transcription arrest: Step back to go forward.

    Science.gov (United States)

    Mullenders, Leon

    2015-12-01

    The disturbance of DNA helix conformation by bulky DNA damage poses hindrance to transcription elongating due to stalling of RNA polymerase at transcription blocking lesions. Stalling of RNA polymerase provokes the formation of R-loops, i.e. the formation of a DNA-RNA hybrid and a displaced single stranded DNA strand as well as displacement of spliceosomes. R-loops are processed into DNA single and double strand breaks by NER factors depending on TC-NER factors leading to genome instability. Moreover, stalling of RNA polymerase induces a strong signal for cell cycle arrest and apoptosis. These toxic and mutagenic effects are counteracted by a rapid recruitment of DNA repair proteins to perform transcription coupled nucleotide excision repair (TC-NER) to remove the blocking DNA lesions and to restore transcription. Recent studies have highlighted the role of backtracking of RNA polymerase to facilitate TC-NER and identified novel factors that play key roles in TC-NER and in restoration of transcription. On the molecular level these factors facilitate stability of the repair complex by promotion and regulation of various post-translational modifications of NER factors and chromatin substrate. In addition, the continuous flow of new factors that emerge from screening assays hints to several regulatory levels to safeguard the integrity of transcription elongation after disturbance by DNA damage that have yet to be explored. Copyright © 2015 Elsevier B.V. All rights reserved.

  8. UV stimulation of DNA-mediated transformation of human cells

    International Nuclear Information System (INIS)

    van Duin, M.; Westerveld, A.; Hoeijmakers, J.H.

    1985-01-01

    Irradiation of dominant marker DNA with UV light (150 to 1,000 J/m2) was found to stimulate the transformation of human cells by this marker from two- to more than fourfold. This phenomenon is also displayed by xeroderma pigmentosum cells, which are deficient in the excision repair of UV-induced pyrimidine dimers in the DNA. Also, exposure to UV of the transfected (xeroderma pigmentosum) cells enhanced the transfection efficiency. Removal of the pyrimidine dimers from the DNA by photoreactivating enzyme before transfection completely abolished the stimulatory effect, indicating that dimer lesions are mainly responsible for the observed enhancement. A similar stimulation of the transformation efficiency is exerted by 2-acetoxy-2-acetylaminofluorene modification of the DNA. These findings suggest that lesions which are targets for the excision repair pathway induce the increase in transformation frequency. The stimulation was found to be independent of sequence homology between the irradiated DNA and the host chromosomal DNA. Therefore, the increase of the transformation frequency is not caused by a mechanism inducing homologous recombination between these two DNAs. UV treatment of DNA before transfection did not have a significant effect on the amount of DNA integrated into the xeroderma pigmentosum genome

  9. Repair of DNA-polypeptide crosslinks by human excision nuclease

    Science.gov (United States)

    Reardon, Joyce T.; Sancar, Aziz

    2006-03-01

    DNA-protein crosslinks are relatively common DNA lesions that form during the physiological processing of DNA by replication and recombination proteins, by side reactions of base excision repair enzymes, and by cellular exposure to bifunctional DNA-damaging agents such as platinum compounds. The mechanism by which pathological DNA-protein crosslinks are repaired in humans is not known. In this study, we investigated the mechanism of recognition and repair of protein-DNA and oligopeptide-DNA crosslinks by the human excision nuclease. Under our assay conditions, the human nucleotide excision repair system did not remove a 16-kDa protein crosslinked to DNA at a detectable level. However, 4- and 12-aa-long oligopeptides crosslinked to the DNA backbone were recognized by some of the damage recognition factors of the human excision nuclease with moderate selectivity and were excised from DNA at relatively efficient rates. Our data suggest that, if coupled with proteolytic degradation of the crosslinked protein, the human excision nuclease may be the major enzyme system for eliminating protein-DNA crosslinks from the genome. damage recognition | nucleotide excision repair

  10. Nucleotide Excision Repair and Transcription-coupled DNA Repair Abrogate the Impact of DNA Damage on Transcription*

    Science.gov (United States)

    Nadkarni, Aditi; Burns, John A.; Gandolfi, Alberto; Chowdhury, Moinuddin A.; Cartularo, Laura; Berens, Christian; Geacintov, Nicholas E.; Scicchitano, David A.

    2016-01-01

    DNA adducts derived from carcinogenic polycyclic aromatic hydrocarbons like benzo[a]pyrene (B[a]P) and benzo[c]phenanthrene (B[c]Ph) impede replication and transcription, resulting in aberrant cell division and gene expression. Global nucleotide excision repair (NER) and transcription-coupled DNA repair (TCR) are among the DNA repair pathways that evolved to maintain genome integrity by removing DNA damage. The interplay between global NER and TCR in repairing the polycyclic aromatic hydrocarbon-derived DNA adducts (+)-trans-anti-B[a]P-N6-dA, which is subject to NER and blocks transcription in vitro, and (+)-trans-anti-B[c]Ph-N6-dA, which is a poor substrate for NER but also blocks transcription in vitro, was tested. The results show that both adducts inhibit transcription in human cells that lack both NER and TCR. The (+)-trans-anti-B[a]P-N6-dA lesion exhibited no detectable effect on transcription in cells proficient in NER but lacking TCR, indicating that NER can remove the lesion in the absence of TCR, which is consistent with in vitro data. In primary human cells lacking NER, (+)-trans-anti-B[a]P-N6-dA exhibited a deleterious effect on transcription that was less severe than in cells lacking both pathways, suggesting that TCR can repair the adduct but not as effectively as global NER. In contrast, (+)-trans-anti-B[c]Ph-N6-dA dramatically reduces transcript production in cells proficient in global NER but lacking TCR, indicating that TCR is necessary for the removal of this adduct, which is consistent with in vitro data showing that it is a poor substrate for NER. Hence, both global NER and TCR enhance the recovery of gene expression following DNA damage, and TCR plays an important role in removing DNA damage that is refractory to NER. PMID:26559971

  11. Formamidopyrimidines in DNA: mechanisms of formation, repair, and biological effects.

    Science.gov (United States)

    Dizdaroglu, Miral; Kirkali, Güldal; Jaruga, Pawel

    2008-12-15

    Oxidatively induced damage to DNA results in a plethora of lesions comprising modified bases and sugars, DNA-protein cross-links, tandem lesions, strand breaks, and clustered lesions. Formamidopyrimidines, 4,6-diamino-5-formamidopyrimidine (FapyAde) and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyGua), are among the major lesions generated in DNA by hydroxyl radical attack, UV radiation, or photosensitization under numerous in vitro and in vivo conditions. They are formed by one-electron reduction of C8-OH-adduct radicals of purines and thus have a common precursor with 8-hydroxypurines generated upon one-electron oxidation. Methodologies using mass spectrometry exist to accurately measure FapyAde and FapyGua in vitro and in vivo. Formamidopyrimidines are repaired by base excision repair. Numerous prokaryotic and eukaryotic DNA glycosylases are highly specific for removal of these lesions from DNA in the first step of this repair pathway, indicating their biological importance. FapyAde and FapyGua are bypassed by DNA polymerases with the insertion of the wrong intact base opposite them, leading to mutagenesis. In mammalian cells, the mutagenicity of FapyGua exceeds that of 8-hydroxyguanine, which is thought to be the most mutagenic of the oxidatively induced lesions in DNA. The background and formation levels of the former in vitro and in vivo equal or exceed those of the latter under various conditions. FapyAde and FapyGua exist in living cells at significant background levels and are abundantly generated upon exposure to oxidative stress. Mice lacking the genes that encode specific DNA glycosylases accumulate these lesions in different organs and, in some cases, exhibit a series of pathological conditions including metabolic syndrome and cancer. Animals exposed to environmental toxins accumulate formamidopyrimidines in their organs. Here, we extensively review the mechanisms of formation, measurement, repair, and biological effects of formamidopyrimidines

  12. non-surgical management of a chronic periapical lesion associated

    African Journals Online (AJOL)

    hi-tech

    2004-02-02

    Feb 2, 2004 ... Retrograde surgery for removal of the suspected cystic lesion was scheduled. As a ... Treatment of an anterior tooth with chronic periapical infection will depend .... involved removal of diseased periapical tissue, and possibly.

  13. NMR studies of the exocyclic 1,N6-ethenodeoxyadenosine adduct (εdA) opposite thymidine in a DNA duplex. Nonplanar alignment of εdA(anti) and dT(anti) at the lesion site

    International Nuclear Information System (INIS)

    Kouchakdjian, M.; Patel, D.J.; Eisenberg, M.; Yarema, K.; Basu, A.; Essigmann, J.

    1991-01-01

    Two-dimensional proton NMR studies are reported on the complementary d(C-A-T-G-T-G-T-A-C)·d(G-T-A-C-εA-C-A-T-G) nonanucleotide duplex (designated εdA·dT 9-mer duplex) containing 1,N 6 -ethenodeoxyadenosine (εdA), a carcinogen-DNA adduct, positioned opposite thymidine in the center of the helix. The authors NMR studies have focused on the conformation of the εdA·dT 9-mer duplex at neutral pH with emphasis on defining the alignment at the dT5·εdA14 lesion site. The through-space NOE distance connectivities establish that both dT5 and εdA14 adopt anti glycosidic torsion angles, are directed into the interior of the helix, and stack with flanking Watson-Crick dG4·dC15 and dG6·dC13 pairs. Furthermore, the d(G4-T5-G6)·d(C13-εA14-C15) trinucleotide segment centered about the dT5·εdA14 lesion site adopts a right-handed helical conformation in solution. Energy minimization computations were undertaken starting from six different alignments of dT5(anti) and εdA14(anti) at the lesion site and were guided by distance constraints defined by lower and upper bounds estimated from NOESY data sets on the εdA·dT 9-mer duplex. The NMR data are consistent with a nonplanar alignment of εdA14(anti) and dT5(anti) with dT5 displaced toward the flanking dG4·dC15 base pair within the d(G4-T5-G6)·d(C13-εA14-C15) segment of the εdA·dT 9-mer duplex

  14. Chloroethylating nitrosoureas in cancer therapy: DNA damage, repair and cell death signaling.

    Science.gov (United States)

    Nikolova, Teodora; Roos, Wynand P; Krämer, Oliver H; Strik, Herwig M; Kaina, Bernd

    2017-08-01

    Chloroethylating nitrosoureas (CNU), such as lomustine, nimustine, semustine, carmustine and fotemustine are used for the treatment of malignant gliomas, brain metastases of different origin, melanomas and Hodgkin disease. They alkylate the DNA bases and give rise to the formation of monoadducts and subsequently interstrand crosslinks (ICL). ICL are critical cytotoxic DNA lesions that link the DNA strands covalently and block DNA replication and transcription. As a result, S phase progression is inhibited and cells are triggered to undergo apoptosis and necrosis, which both contribute to the effectiveness of CNU-based cancer therapy. However, tumor cells resist chemotherapy through the repair of CNU-induced DNA damage. The suicide enzyme O 6 -methylguanine-DNA methyltransferase (MGMT) removes the precursor DNA lesion O 6 -chloroethylguanine prior to its conversion into ICL. In cells lacking MGMT, the formed ICL evoke complex enzymatic networks to accomplish their removal. Here we discuss the mechanism of ICL repair as a survival strategy of healthy and cancer cells and DNA damage signaling as a mechanism contributing to CNU-induced cell death. We also discuss therapeutic implications and strategies based on sequential and simultaneous treatment with CNU and the methylating drug temozolomide. Copyright © 2017 Elsevier B.V. All rights reserved.

  15. Bisphenol a promotes cell survival following oxidative DNA damage in mouse fibroblasts.

    Directory of Open Access Journals (Sweden)

    Natalie R Gassman

    Full Text Available Bisphenol A (BPA is a biologically active industrial chemical used in production of consumer products. BPA has become a target of intense public scrutiny following concerns about its association with human diseases such as obesity, diabetes, reproductive disorders, and cancer. Recent studies link BPA with the generation of reactive oxygen species, and base excision repair (BER is responsible for removing oxidatively induced DNA lesions. Yet, the relationship between BPA and BER has yet to be examined. Further, the ubiquitous nature of BPA allows continuous exposure of the human genome concurrent with the normal endogenous and exogenous insults to the genome, and this co-exposure may impact the DNA damage response and repair. To determine the effect of BPA exposure on base excision repair of oxidatively induced DNA damage, cells compromised in double-strand break repair were treated with BPA alone or co-exposed with either potassium bromate (KBrO3 or laser irradiation as oxidative damaging agents. In experiments with KBrO3, co-treatment with BPA partially reversed the KBrO3-induced cytotoxicity observed in these cells, and this was coincident with an increase in guanine base lesions in genomic DNA. The improvement in cell survival and the increase in oxidatively induced DNA base lesions were reminiscent of previous results with alkyl adenine DNA glycosylase-deficient cells, suggesting that BPA may prevent initiation of repair of oxidized base lesions. With laser irradiation-induced DNA damage, treatment with BPA suppressed DNA repair as revealed by several indicators. These results are consistent with the hypothesis that BPA can induce a suppression of oxidized base lesion DNA repair by the base excision repair pathway.

  16. Periapical lesions: diagnosis and treatment

    OpenAIRE

    García-Rubio, A.; Bujaldón-Daza, A.L.; Rodríguez-Archilla, A.

    2015-01-01

    Las lesiones periapicales resultado de la necrosis de la pulpa dental son las patologías que más frecuentemente ocurren encontradas en el hueso alveolar. El tratamiento consiste en la eliminación de los agentes infecciosos mediante el tratamiento del canal radicular, permitiendo la cicatrización de la lesión. Periapical lesions, which are a result of the necrosis of the dental pulp, are the most frequently occurring diseases found in the alveolar bone. The treatment involves the removal of...

  17. In vitro Repair of Oxidative DNA Damage by Human Nucleotide Excision Repair System: Possible Explanation for Neurodegeneration in Xeroderma Pigmentosum Patients

    Science.gov (United States)

    Reardon, Joyce T.; Bessho, Tadayoshi; Kung, Hsiang Chuan; Bolton, Philip H.; Sancar, Aziz

    1997-08-01

    Xeroderma pigmentosum (XP) patients fail to remove pyrimidine dimers caused by sunlight and, as a consequence, develop multiple cancers in areas exposed to light. The second most common sign, present in 20-30% of XP patients, is a set of neurological abnormalities caused by neuronal death in the central and peripheral nervous systems. Neural tissue is shielded from sunlight-induced DNA damage, so the cause of neurodegeneration in XP patients remains unexplained. In this study, we show that two major oxidative DNA lesions, 8-oxoguanine and thymine glycol, are excised from DNA in vitro by the same enzyme system responsible for removing pyrimidine dimers and other bulky DNA adducts. Our results suggest that XP neurological disease may be caused by defective repair of lesions that are produced in nerve cells by reactive oxygen species generated as by-products of an active oxidative metabolism.

  18. Premalignant Lesions in the Kidney

    Directory of Open Access Journals (Sweden)

    Ziva Kirkali

    2001-01-01

    Full Text Available Renal cell carcinoma (RCC is the most malignant urologic disease. Different lesions, such as dysplasia in the tubules adjacent to RCC, atypical hyperplasia in the cyst epithelium of von Hippel-Lindau syndrome, and adenoma have been described for a number of years as possible premalignant changes or precursor lesions of RCC. In two recent papers, kidneys adjacent to RCC or removed from other causes were analyzed, and dysplastic lesions were identified and defined in detail. Currently renal intraepithelial neoplasia (RIN is the proposed term for classification. The criteria for a lesion to be defined as premalignant are (1 morphological similarity; (2 spatial association; (3 development of microinvasive carcinoma; (4 higher frequency, severity, and extent then invasive carcinoma; (5 progression to invasive cancer; and (6 similar genetic alterations. RIN resembles the neoplastic cells of RCC. There is spatial association. Progression to invasive carcinoma is described in experimental cancer models, and in some human renal tumors. Similar molecular alterations are found in some putative premalignant changes. The treatment for RCC is radical or partial nephrectomy. Preneoplastic lesions may remain in the renal remnant in patients treated by partial nephrectomy and may be the source of local recurrences. RIN seems to be a biologic precursor of some RCCs and warrants further investigation. Interpretation and reporting of these lesions would reveal important resources for the biological nature and clinical significance. The management of RIN diagnosed in a renal biopsy and partial nephrectomy needs to be answered.

  19. Differences in pyrimidine dimer removal between rat skin cells in vitro and in vivo

    International Nuclear Information System (INIS)

    Mullaart, E.; Lohman, P.H.; Vijg, J.

    1988-01-01

    Pyrimidine dimers, the most abundant type of DNA lesions induced by ultraviolet light (UV), are rapidly repaired in human skin fibroblasts in vitro. In the same cell type from rats, however, there is hardly any removal of such dimers. To investigate whether this low capacity of rat skin cells to repair lesions in their DNA is an inherent characteristic of this species or an artifact due to cell culturing, we measured the removal of UV-induced pyrimidine dimers from rat epidermal keratinocytes both in vitro and in vivo. Epidermal keratinocytes in vitro were unable to remove any dimers over the first 3 h after UV-irradiation, while only about 20% was removed during a repair period of 24 h. In this respect, these cells were not different from cultured rat fibroblasts. In contrast to the results obtained with keratinocytes in vitro, we observed a rapid repair of pyrimidine dimers in UV-irradiated keratinocytes in vivo over the first 3 h; this rapid repair phase was followed by a much slower repair phase between 3 and 24 h. These results are discussed in terms of the possibility that mammalian cells are able to switch from one DNA repair pathway to another

  20. The AID-induced DNA damage response in chromatin

    DEFF Research Database (Denmark)

    Daniel, Jeremy A; Nussenzweig, André

    2013-01-01

    Chemical modifications to the DNA and histone protein components of chromatin can modulate gene expression and genome stability. Understanding the physiological impact of changes in chromatin structure remains an important question in biology. As one example, in order to generate antibody diversity...... with somatic hypermutation and class switch recombination, chromatin must be made accessible for activation-induced cytidine deaminase (AID)-mediated deamination of cytosines in DNA. These lesions are recognized and removed by various DNA repair pathways but, if not handled properly, can lead to formation...... of oncogenic chromosomal translocations. In this review, we focus the discussion on how chromatin-modifying activities and -binding proteins contribute to the native chromatin environment in which AID-induced DNA damage is targeted and repaired. Outstanding questions remain regarding the direct roles...

  1. Randomized Clinical Trials on Deep Carious Lesions

    DEFF Research Database (Denmark)

    Bjørndal, Lars; Fransson, Helena; Bruun, Gitte

    2017-01-01

    nonselective carious removal to hard dentin with or without pulp exposure. The aim of this article was to report the 5-y outcome on these previously treated patients having radiographically well-defined carious lesions extending into the pulpal quarter of the dentin but with a well-defined radiodense zone...... pulp exposures per se were included as failures. Pulp exposure rate was significantly lower in the stepwise carious removal group (21.2% vs. 35.5%; P = 0.014). Irrespective of pulp exposure status, the difference (13.3%) was still significant when sustained pulp vitality without apical radiolucency......) in deep carious lesions in adults. In conclusion, the stepwise carious removal group had a significantly higher proportion of pulps with sustained vitality without apical radiolucency versus nonselective carious removal of deep carious lesions in adult teeth at 5-y follow-up (ClinicalTrials.gov NCT...

  2. A combined alignment and registration scheme of psoriasis lesion |images

    DEFF Research Database (Denmark)

    Maletti, Gabriela Mariel; Ersbøll, Bjarne Kjær

    2003-01-01

    A two-stage registration scheme of psoriasis lesion patterns is proposed. In the first stage, global rotation and translation effects of assumed equally scaled psoriasis lesion patterns are removed. In the second stage, only local translation effects are removed. In both stages a novel algorithm...

  3. Management of Preinvasive Lesions.

    Science.gov (United States)

    Patrono, Maria G; Corzo, Camila; Iniesta, Maria; Ramirez, Pedro T

    2017-12-01

    Serous tubal intraepithelial carcinoma is considered the precursor lesion of high-grade serous carcinoma, and found in both low-risk and high-risk populations. Isolated serous tubal intraepithelial carcinomas in patients with BRCA1/2 mutations are detected in ∼2% of patients undergoing risk-reducing bilateral salpingo-oophorectomy and even with removal of the tubes and ovaries the rate of developing primary peritoneal carcinoma following remains up to 7.5%. Postoperative recommendations after finding incidental STICs remain unclear and surgical staging, adjuvant chemotherapy, or observation have been proposed. Discovery of STIC should prompt consideration of hereditary cancer program referral for BRCA1/2 mutation screening.

  4. The cyclopurine deoxynucleosides: DNA repair, biological effects, mechanistic insights, and unanswered questions.

    Science.gov (United States)

    Brooks, Philip J

    2017-06-01

    Patients with the genetic disease xeroderma pigmentosum (XP) who lack the capacity to carry out nucleotides excision repair (NER) have a dramatically elevated risk of skin cancer on sun exposed areas of the body. NER is the DNA repair mechanism responsible for the removal of DNA lesions resulting from ultraviolet light. In addition, a subset of XP patients develop a progressive neurodegenerative disease, referred to as XP neurologic disease, which is thought to be the result of accumulation of endogenous DNA lesions that are repaired by NER but not other repair pathways. The 8,5-cyclopurine deoxynucleotides (cyPu) have emerged as leading candidates for such lesions, in that they result from the reaction of the hydroxyl radical with DNA, are strong blocks to transcription in human cells, and are repaired by NER but not base excision repair. Here I present a focused perspective on progress into understating the repair and biological effects of these lesions. In doing so, I emphasize the role of Tomas Lindahl and his laboratory in stimulating cyPu research. I also include a critical evaluation of the evidence supporting a role for cyPu lesions in XP neurologic disease, with a focus on outstanding questions, and conceptual and technologic challenges. Copyright © 2017. Published by Elsevier Inc.

  5. Detection of Fundus Lesions Using Classifier Selection

    Science.gov (United States)

    Nagayoshi, Hiroto; Hiramatsu, Yoshitaka; Sako, Hiroshi; Himaga, Mitsutoshi; Kato, Satoshi

    A system for detecting fundus lesions caused by diabetic retinopathy from fundus images is being developed. The system can screen the images in advance in order to reduce the inspection workload on doctors. One of the difficulties that must be addressed in completing this system is how to remove false positives (which tend to arise near blood vessels) without decreasing the detection rate of lesions in other areas. To overcome this difficulty, we developed classifier selection according to the position of a candidate lesion, and we introduced new features that can distinguish true lesions from false positives. A system incorporating classifier selection and these new features was tested in experiments using 55 fundus images with some lesions and 223 images without lesions. The results of the experiments confirm the effectiveness of the proposed system, namely, degrees of sensitivity and specificity of 98% and 81%, respectively.

  6. Modulation of mutagen-induced biological effects by inhibitors of DNA repair

    International Nuclear Information System (INIS)

    Natarajan, A.T.; Mullenders, L.F.H.; Zwanenburg, T.S.B.

    1986-01-01

    When lesions are induced in the DNA by mutagenic agents, they are subjected to cellular repair. Unrepaired and misrepaired lesions lead to biological effects, such as cell killing, point mutations and chromosomal alterations (aberrations and sister chromatid exchanges - SCEs). It is very difficult to directly correlate any particular type of lesion to a specific biological effect. However, in specific cases, this has been done. For example, short wave UV induced biological effects (cell killing, chromosomal alterations) result predominantly from induced cyclobutane dimers and by photoreactivation experiments, one can demonstrate that with the removal of dimers all types biological effects are diminished. In cases where many types of lesions are considered responsible for the observed biological effects other strategies have been employed to identify the possible lesion. The frequencies of induced chromosomal alterations and point mutations increase with the dose of the mutagen employed and an inhibition of DNA repair following treatment with the mutagen. Prevention of the cells from dividing following mutagen treatment allows them to repair premutational damage, thus reducing the biological effects induced. By comprehensive studies involving quantification of primary DNA lesions, their repair and biological effects will enable us to understand to some extent the complex processes involved in the manifestation of specific biological effects that follow the treatment of cells with mutagenic carcinogens

  7. Presence of High-Risk HPV mRNA in Relation to Future High-Grade Lesions among High-Risk HPV DNA Positive Women with Minor Cytological Abnormalities.

    Directory of Open Access Journals (Sweden)

    Hanna Johansson

    Full Text Available Continuous expression of E6- and E7-oncogenes of high-risk human papillomavirus (HPV types is necessary for the development and maintenance of the dysplastic phenotype. The aim of the study was to determine the sensitivity and specificity of the APTIMA HPV mRNA assay (Hologic in predicting future development of high-grade cervical intraepithelial neoplasia (CIN among high-risk HPV-DNA-positive women with atypical squamous cells of undetermined significance (ASCUS or low-grade squamous epithelial lesion (LSIL cytology.Archived SurePath cervical samples of women ≥ 35 years of age with high-risk HPV DNA-positive ASCUS (n = 211 or LSIL, (n = 131 were tested for the presence of high-risk HPV E6/E7 mRNA using the APTIMA HPV assay, and the women were monitored for development of histopathologically verified CIN2+.Twenty-nine percent (61/211 of the women in the ASCUS group, and 34.3% (45/131 in the LSIL group developed CIN2+ within 4.5 years of follow-up. The prevalence of HPV mRNA was 90.0% (95% CI 85.9-94.0 among women with ASCUS and 95.4% (95% CI 91.8-99.0 among women with LSIL. The presence of HPV E6/E7 mRNA was associated with future development of CIN2+ among women with ASCUS and LSIL (p=0.02. The mRNA assay demonstrated high sensitivity in predicting future CIN2+ and CIN3 for index ASCUS (96.7%; 95% CI 87.6-99.4 and 100%; 95% CI 82.2-100, respectively and LSIL (97.8%, 95% CI 86.8-99.9 and 100%, 95% CI 79.9-100, respectively. The corresponding specificity was low, 12.7% (95% CI 7.9-19.3 and 5.8% (95% CI 2.2-13.6, for future CIN2+, respectively. The negative predictive value of the HPV mRNA assay for detecting future CIN3 was 100%, since no mRNA-negative woman developed CIN3 (0/27 as compared to 13.6% (43/315 of the mRNA-positive women (p = 0.03.The APTIMA mRNA assay demonstrated high sensitivity but low specificity in predicting future CIN2+ among women with minor cytological abnormalities. The assay had high negative predictive value for future

  8. Presence of High-Risk HPV mRNA in Relation to Future High-Grade Lesions among High-Risk HPV DNA Positive Women with Minor Cytological Abnormalities

    Science.gov (United States)

    Johansson, Hanna; Bjelkenkrantz, Kaj; Darlin, Lotten; Dilllner, Joakim; Forslund, Ola

    2015-01-01

    Objective Continuous expression of E6- and E7-oncogenes of high-risk human papillomavirus (HPV) types is necessary for the development and maintenance of the dysplastic phenotype. The aim of the study was to determine the sensitivity and specificity of the APTIMA HPV mRNA assay (Hologic) in predicting future development of high-grade cervical intraepithelial neoplasia (CIN) among high-risk HPV-DNA-positive women with atypical squamous cells of undetermined significance (ASCUS) or low-grade squamous epithelial lesion (LSIL) cytology. Methods Archived SurePath cervical samples of women ≥ 35 years of age with high-risk HPV DNA-positive ASCUS (n = 211) or LSIL, (n = 131) were tested for the presence of high-risk HPV E6/E7 mRNA using the APTIMA HPV assay, and the women were monitored for development of histopathologically verified CIN2+. Results Twenty-nine percent (61/211) of the women in the ASCUS group, and 34.3% (45/131) in the LSIL group developed CIN2+ within 4.5 years of follow-up. The prevalence of HPV mRNA was 90.0% (95% CI 85.9-94.0) among women with ASCUS and 95.4% (95% CI 91.8-99.0) among women with LSIL. The presence of HPV E6/E7 mRNA was associated with future development of CIN2+ among women with ASCUS and LSIL (p=0.02). The mRNA assay demonstrated high sensitivity in predicting future CIN2+ and CIN3 for index ASCUS (96.7%; 95% CI 87.6-99.4 and 100%; 95% CI 82.2-100, respectively) and LSIL (97.8%, 95% CI 86.8-99.9 and 100%, 95% CI 79.9-100, respectively). The corresponding specificity was low, 12.7% (95% CI 7.9-19.3) and 5.8% (95% CI 2.2-13.6), for future CIN2+, respectively. The negative predictive value of the HPV mRNA assay for detecting future CIN3 was 100%, since no mRNA-negative woman developed CIN3 (0/27) as compared to 13.6% (43/315) of the mRNA-positive women (p = 0.03). Conclusion The APTIMA mRNA assay demonstrated high sensitivity but low specificity in predicting future CIN2+ among women with minor cytological abnormalities. The assay had

  9. DNA adducts and human atherosclerotic lesions

    Czech Academy of Sciences Publication Activity Database

    Binková, Blanka; Strejc, P.; Boubelík, O.; Stávková, Zdena; Chvátalová, Irena; Šrám, Radim

    2001-01-01

    Roč. 204, - (2001), s. 49-54 ISSN 1438-4639 R&D Projects: GA MŽP SI/340/00 Institutional research plan: CEZ:AV0Z5039906 Keywords : atherosclerosis * autopsy thoracic aortas Subject RIV: DN - Health Impact of the Environment Quality Impact factor: 0.480, year: 2001

  10. DNA-Mediated Electrochemistry

    Science.gov (United States)

    Gorodetsky, Alon A.; Buzzeo, Marisa C.

    2009-01-01

    The base pair stack of DNA has been demonstrated as a medium for long range charge transport chemistry both in solution and at DNA-modified surfaces. This chemistry is exquisitely sensitive to structural perturbations in the base pair stack as occur with lesions, single base mismatches, and protein binding. We have exploited this sensitivity for the development of reliable electrochemical assays based on DNA charge transport at self-assembled DNA monolayers. Here we discuss the characteristic features, applications, and advantages of DNA-mediated electrochemistry. PMID:18980370

  11. Hair Removal

    Science.gov (United States)

    ... Staying Safe Videos for Educators Search English Español Hair Removal KidsHealth / For Teens / Hair Removal What's in ... you need any of them? Different Types of Hair Before removing hair, it helps to know about ...

  12. Aging and DNA repair capability. [Review

    Energy Technology Data Exchange (ETDEWEB)

    Tice, R R

    1977-01-01

    A review of the literature on DNA repair processes in relation to aging is presented under the following headings: DNA repair processes; age-related occurrence of unrepaired DNA lesions; DNA repair capability as a function of age; tissue-specific DNA repair capability; acceleration of the aging process by exposure to DNA damaging agents; human genetic syndromes; and longevity and DNA repair processes. (HLW)

  13. Analysis of the giant genomes of Fritillaria (Liliaceae) indicates that a lack of DNA removal characterizes extreme expansions in genome size

    Czech Academy of Sciences Publication Activity Database

    Kelly, L.J.; Renny-Byfield, S.; Macas, Jiří; Novák, Petr; Neumann, Pavel; Lysák, M.; Day, P.D.; Berger, M.; Fay, M. F.; Nichols, R. A.; Leitch, A. R.; Leitch, I. J.

    2015-01-01

    Roč. 208, č. 2 (2015), s. 596-607 ISSN 0028-646X R&D Projects: GA ČR GBP501/12/G090 Institutional support: RVO:60077344 Keywords : DNA deletion * Fritillaria * Liliaceae * genome size evolution Subject RIV: EB - Genetics ; Molecular Biology Impact factor: 7.210, year: 2015

  14. Impact of DNA repair on the dose-response of colorectal cancer formation induced by dietary carcinogens.

    Science.gov (United States)

    Fahrer, Jörg; Kaina, Bernd

    2017-08-01

    Colorectal cancer (CRC) is one of the most frequently diagnosed cancers, which is causally linked to dietary habits, notably the intake of processed and red meat. Processed and red meat contain dietary carcinogens, including heterocyclic aromatic amines (HCAs) and N-nitroso compounds (NOC). NOC are agents that induce various N-methylated DNA adducts and O 6 -methylguanine (O 6 -MeG), which are removed by base excision repair (BER) and O 6 -methylguanine-DNA methyltransferase (MGMT), respectively. HCAs such as the highly mutagenic 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) cause bulky DNA adducts, which are removed from DNA by nucleotide excision repair (NER). Both O 6 -MeG and HCA-induced DNA adducts are linked to the occurrence of KRAS and APC mutations in colorectal tumors of rodents and humans, thereby driving CRC initiation and progression. In this review, we focus on DNA repair pathways removing DNA lesions induced by NOC and HCA and assess their role in protecting against mutagenicity and carcinogenicity in the large intestine. We further discuss the impact of DNA repair on the dose-response relationship in colorectal carcinogenesis in view of recent studies, demonstrating the existence of 'no effect' point of departures (PoDs), i.e. thresholds for genotoxicity and carcinogenicity. The available data support the threshold concept for NOC with DNA repair being causally involved. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Characterization of antibodies to dihydrothymine, a radiolysis product of DNA

    International Nuclear Information System (INIS)

    Hubbard, K.; Ide, H.; Erlanger, B.F.; Wallace, S.S.

    1989-01-01

    Antibodies to dihydrothymine were elicited by immunizing rabbits with dihydrothymidine monophosphate conjugated by carbodiimide to BSA. By use of an ELISA assay, the antibodies produced were found to be specific for dihydrothymine. Hapten inhibition studies showed that dihydrothymidine monophosphate was 3 orders of magnitude more effective as an inhibitor than thymidine monophosphate and 4 orders of magnitude more effective than thymidine glycol monophosphate. With DNA containing dihydrothymine, antibody reactivity was observed at 20 fmol of dihydrothymine, which is approximately 0.1 dihydrothymine per 10,000 bases. Thus, the assay is very sensitive. The antibody reacted with denatured DNA containing dihydrothymine but not with native DNA containing this lesion. The antibody was used for measurement of in vivo incorporation of dihydrothymidine in wild-type Escherichia coli or mutants defective in their ability to remove dihydrothymine from DNA or in the de novo synthesis of thymidylate. Lastly, antibodies to dihydrothymine were use to quantitate the formation of dihydrothymine in DNA X-irradiated under N2. Production of dihydrothymine in irradiated DNA correlated with the level of reducing species produced by X-rays, and dihydrothymine was produced preferentially in irradiated single-stranded or denatured DNA as compared to irradiated duplex DNA

  16. Functional characterization of 8-oxoguanine DNA glycosylase of Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Carolina Furtado

    Full Text Available The oxidative lesion 8-oxoguanine (8-oxoG is removed during base excision repair by the 8-oxoguanine DNA glycosylase 1 (Ogg1. This lesion can erroneously pair with adenine, and the excision of this damaged base by Ogg1 enables the insertion of a guanine and prevents DNA mutation. In this report, we identified and characterized Ogg1 from the protozoan parasite Trypanosoma cruzi (TcOgg1, the causative agent of Chagas disease. Like most living organisms, T. cruzi is susceptible to oxidative stress, hence DNA repair is essential for its survival and improvement of infection. We verified that the TcOGG1 gene encodes an 8-oxoG DNA glycosylase by complementing an Ogg1-defective Saccharomyces cerevisiae strain. Heterologous expression of TcOGG1 reestablished the mutation frequency of the yeast mutant ogg1(-/- (CD138 to wild type levels. We also demonstrate that the overexpression of TcOGG1 increases T. cruzi sensitivity to hydrogen peroxide (H(2O(2. Analysis of DNA lesions using quantitative PCR suggests that the increased susceptibility to H(2O(2 of TcOGG1-overexpressor could be a consequence of uncoupled BER in abasic sites and/or strand breaks generated after TcOgg1 removes 8-oxoG, which are not rapidly repaired by the subsequent BER enzymes. This hypothesis is supported by the observation that TcOGG1-overexpressors have reduced levels of 8-oxoG both in the nucleus and in the parasite mitochondrion. The localization of TcOgg1 was examined in parasite transfected with a TcOgg1-GFP fusion, which confirmed that this enzyme is in both organelles. Taken together, our data indicate that T. cruzi has a functional Ogg1 ortholog that participates in nuclear and mitochondrial BER.

  17. Dynamic two-stage mechanism of versatile DNA damage recognition by xeroderma pigmentosum group C protein

    Energy Technology Data Exchange (ETDEWEB)

    Clement, Flurina C.; Camenisch, Ulrike; Fei, Jia; Kaczmarek, Nina; Mathieu, Nadine [Institute of Pharmacology and Toxicology, University of Zuerich-Vetsuisse, Winterthurerstrasse 260, CH-8057 Zuerich (Switzerland); Naegeli, Hanspeter, E-mail: naegelih@vetpharm.uzh.ch [Institute of Pharmacology and Toxicology, University of Zuerich-Vetsuisse, Winterthurerstrasse 260, CH-8057 Zuerich (Switzerland)

    2010-03-01

    The recognition and subsequent repair of DNA damage are essential reactions for the maintenance of genome stability. A key general sensor of DNA lesions is xeroderma pigmentosum group C (XPC) protein, which recognizes a wide variety of helix-distorting DNA adducts arising from ultraviolet (UV) radiation, genotoxic chemicals and reactive metabolic byproducts. By detecting damaged DNA sites, this unique molecular sensor initiates the global genome repair (GGR) pathway, which allows for the removal of all the aforementioned lesions by a limited repertoire of excision factors. A faulty GGR activity causes the accumulation of DNA adducts leading to mutagenesis, carcinogenesis, neurological degeneration and other traits of premature aging. Recent findings indicate that XPC protein achieves its extraordinary substrate versatility by an entirely indirect readout strategy implemented in two clearly discernible stages. First, the XPC subunit uses a dynamic sensor interface to monitor the double helix for the presence of non-hydrogen-bonded bases. This initial screening generates a transient nucleoprotein intermediate that subsequently matures into the ultimate recognition complex by trapping undamaged nucleotides in the abnormally oscillating native strand, in a way that no direct contacts are made between XPC protein and the offending lesion itself. It remains to be elucidated how accessory factors like Rad23B, centrin-2 or the UV-damaged DNA-binding complex contribute to this dynamic two-stage quality control process.

  18. Differential repair of etheno-DNA adducts by bacterial and human AlkB proteins.

    Science.gov (United States)

    Zdżalik, Daria; Domańska, Anna; Prorok, Paulina; Kosicki, Konrad; van den Born, Erwin; Falnes, Pål Ø; Rizzo, Carmelo J; Guengerich, F Peter; Tudek, Barbara

    2015-06-01

    AlkB proteins are evolutionary conserved Fe(II)/2-oxoglutarate-dependent dioxygenases, which remove alkyl and highly promutagenic etheno(ɛ)-DNA adducts, but their substrate specificity has not been fully determined. We developed a novel assay for the repair of ɛ-adducts by AlkB enzymes using oligodeoxynucleotides with a single lesion and specific DNA glycosylases and AP-endonuclease for identification of the repair products. We compared the repair of three ɛ-adducts, 1,N(6)-ethenoadenine (ɛA), 3,N(4)-ethenocytosine (ɛC) and 1,N(2)-ethenoguanine (1,N(2)-ɛG) by nine bacterial and two human AlkBs, representing four different structural groups defined on the basis of conserved amino acids in the nucleotide recognition lid, engaged in the enzyme binding to the substrate. Two bacterial AlkB proteins, MT-2B (from Mycobacterium tuberculosis) and SC-2B (Streptomyces coelicolor) did not repair these lesions in either double-stranded (ds) or single-stranded (ss) DNA. Three proteins, RE-2A (Rhizobium etli), SA-2B (Streptomyces avermitilis), and XC-2B (Xanthomonas campestris) efficiently removed all three lesions from the DNA substrates. Interestingly, XC-2B and RE-2A are the first AlkB proteins shown to be specialized for ɛ-adducts, since they do not repair methylated bases. Three other proteins, EcAlkB (Escherichia coli), SA-1A, and XC-1B removed ɛA and ɛC from ds and ssDNA but were inactive toward 1,N(2)-ɛG. SC-1A repaired only ɛA with the preference for dsDNA. The human enzyme ALKBH2 repaired all three ɛ-adducts in dsDNA, while only ɛA and ɛC in ssDNA and repair was less efficient in ssDNA. ALKBH3 repaired only ɛC in ssDNA. Altogether, we have shown for the first time that some AlkB proteins, namely ALKBH2, RE-2A, SA-2B and XC-2B can repair 1,N(2)-ɛG and that ALKBH3 removes only ɛC from ssDNA. Our results also suggest that the nucleotide recognition lid is not the sole determinant of the substrate specificity of AlkB proteins. Copyright © 2015 Elsevier B

  19. Mutagenesis and repair of DNA

    International Nuclear Information System (INIS)

    Janion, C.; Grzesiuk, E.; Fabisiewicz, A.; Tudek, B.; Ciesla, J.; Graziewicz, M.; Wojcik, A.; Speina, E.

    1998-01-01

    mutagenic lesions in phage M13 DNA after DMS +NaOH treatment strongly indicate that Fapy-7meA is a mutagenic base. The loss of 7meAde, the precursor of Fapy-7meA, from DNA of M13 resulted in a decline in mutagenic potency at a rate proportional to the amount of bases removed. (author)

  20. [The treatment of decubitus lesions].

    Science.gov (United States)

    Fugazza, G; Moroni, S; Bona, F

    1995-01-01

    The authors present a plan for pharmacological treatment of pressure sores in patients affected by neurological pathologies: cerebrovascular accidents, head injuries, spinal cord injuries. This plan is easily applicable to all pressure sores included between first and third degree of the Reuler and Cooney classification. Authors identified some drugs specifically usefull in different cutaneous lesion degrees. Skin lesions and employed medicines are described as follows: Erythema: semi occlusive bandage with porous adsorbing membrane. This dressing must be left in for five days at least. Excoriation: bactericidal or bacteriostatic medicines if it's situated in a non pressed area while the same dressing utilized for erythema if it's localized in a pressed area. Pressure sores: if there is local infection cleanse the wound from bacterial defilement using topic antibiotics apply compresses with vitamin C if the cutaneous lesion is larger than deeper, Cadexomero lodico if it's deeper than larger. Fistulas: wadding with tablets of collagen. Necrobiosis: complete or partial surgical removal of eschar preceded by the use of enzymatic drugs when eschar is firmly adherent to subcutaneous tissues. The first group collects 9 patients with stroke and head injury: 8 with sacral and 1 with heel pressure sores. First degree pressure sores heal within 45 days and third degree lesions within 160 days. The second group collects 10 spinal cord injury patients mostly with complete lesion among which: 7 sacral, 1 heel, 1 ischiatic and 1 malleolar lesions. First degree pressure sores heal within 30 days, third degree pressure sores heal within 200 days. Healing time are considered acceptable. Pressure sores recovery swiftness can be related to different factors such as pressure sores sterness, neurological pathology and arising of clinical complication (hyperthermia, infections, low serum albumin values, etc).

  1. DNA repair and cancer

    International Nuclear Information System (INIS)

    Rathore, Shakuntla; Joshi, Pankaj Kumar; Gaur, Sudha

    2012-01-01

    DNA repair refers to a collection of processes by which a cell identifies and corrects damage to the DNA molecule that encode it's genome. In human cells, both normal metabolic activities and environmental factors such as UV light and radiation can cause DNA damage, resulting in as many one million individual molecular lesions per day. Many of these lesions cause structural damage to the DNA molecule and can alter or eliminate the cell's ability to transcribe the gene that the affected DNA encodes. Other lesions include potentially harmful mutation in cell's genome which affect the survival of it's daughter cells after it undergoes mitosis. As a consequence, the DNA repair process is constantly active as it responds to damage in the DNA structure. Inherited mutation that affect DNA repair genes are strongly associated with high cancer risks in humans. Hereditary non polyposis colorectal cancer (HNPCC) is strongly associated with specific mutation in the DNA mismatch repair pathway. BRCA1, BRCA2 two famous mutation conferring a hugely increased risk of breast cancer on carrier, are both associated with a large number of DNA repair pathway, especially NHEJ and homologous recombination. Cancer therapy procedures such as chemotherapy and radiotherapy work by overwhelming the capacity of the cell to repair DNA damage, resulting in cell death. Cells that are most rapidly dividing most typically cancer cells are preferentially affected. The side effect is that other non-cancerous but rapidly dividing cells such as stem cells in the bone marrow are also affected. Modern cancer treatment attempt to localize the DNA damage to cells and tissue only associated with cancer, either by physical means (concentrating the therapeutic agent in the region of the tumor) or by biochemical means (exploiting a feature unique to cancer cells in the body). (author)

  2. Hidden in Plain Sight: Subtle Effects of the 8-Oxoguanine Lesion on the Structure, Dynamics, and Thermodynamics of a 15-Base-Pair Oligodeoxynucleotide Duplex†

    Science.gov (United States)

    Crenshaw, Charisse M.; Wade, Jacqueline E.; Arthanari, Haribabu; Frueh, Dominique; Lane, Benjamin F.; Núñez, Megan E.

    2011-01-01

    The base lesion 8-oxoguanine is formed readily by oxidation of DNA, potentially leading to G→T transversion mutations. Despite the apparent similarity of 8-oxoguanine-cytosine base pairs to normal guanine-cytosine base pairs, cellular base excision repair systems effectively recognize the lesion base. Here we apply several techniques to examine a single 8-oxoguanine lesion at the center of a nonpalindromic 15-mer duplex oligonucleotide in an effort to determine what, if anything, distinguishes an 8-oxoguanine-cytosine base pair from a normal base pair. The lesion duplex is globally almost indistinguishable from the unmodified parent duplex using CD spectroscopy and UV melting thermodynamics. The DNA mismatch-detecting photocleavage agent Rh(bpy)2chrysi3+ cleaves only weakly and nonspecifically, revealing that the 8oxoG-C pair is locally stable at the level of the individual base pairs. NMR spectra are also consistent with a well-conserved B-form duplex structure. In the 2D NOESY spectra, base-sugar and imino-imino crosspeaks are strikingly similar between parent and lesion duplexes. Changes in chemical shift due to the 8oxoG lesion are localized to its complementary cytosine and to the 2–3 base pairs immediately flanking the lesion on the lesion strand. Residues further removed from the lesion are shown to be unperturbed by its presence. Notably, imino exchange experiments indicate that the 8-oxoguanine-cytosine pair is strong and stable, with an apparent equilibrium constant for opening equal to that of other internal guanine-cytosine base pairs, on the order of 10−6. This collection of experiments shows that the 8-oxoguanine-cytosine base pair is incredibly stable and similar to the native pair. PMID:21902242

  3. Oropharynx lesion biopsy

    Science.gov (United States)

    ... as papilloma) Fungal infections (such as candida) Histoplasmosis Oral lichen planus Precancerous sore (leukoplakia) Viral infections (such as Herpes simplex) Risks Risks of the procedure may ... Throat lesion biopsy; Biopsy - mouth or throat; Mouth lesion biopsy; Oral cancer - biopsy ...

  4. Prevalent Bacterial Species and Novel Phylotypes in Advanced Noma Lesions

    OpenAIRE

    Paster, B. J.; Falkler, Jr., W. A.; Enwonwu, C. O.; Idigbe, E. O.; Savage, K. O.; Levanos, V. A.; Tamer, M. A.; Ericson, R. L.; Lau, C. N.; Dewhirst, F. E.

    2002-01-01

    The purpose of this study was to determine the bacterial diversity in advanced noma lesions using culture-independent molecular methods. 16S ribosomal DNA bacterial genes from DNA isolated from advanced noma lesions of four Nigerian children were PCR amplified with universally conserved primers and spirochetal selective primers and cloned into Escherichia coli. Partial 16S rRNA sequences of approximately 500 bases from 212 cloned inserts were used initially to determine species identity or cl...

  5. Periodontal bone lesions

    International Nuclear Information System (INIS)

    Linden, L.W.J. van der.

    1985-01-01

    In the course of life the periodontum is subject to changes which may be physiological or pathological. Intraoral radiographs give insight into the hard structures of the dentomaxillar region and provides information on lesions in the bone of the periodontum in that they show radiopacities and radiolucencies caused by such lesions. In this thesis the relation is investigated between the true shape and dimensions of periodontal bone lesions and their radiographic images. A method is developed and tested of making standardized and reproducible radiographs suitable for longitudinal studies of periodontal lesions. Also the possibility is demonstrated of an objective and reproducible interpretation of radiographic characteristics of periodontal bone lesions. (Auth.)

  6. CHOLECYSTOKININ RECEPTOR ANTAGONIST HALTS PROGRESSION OF PANCREATIC CANCER PRECURSOR LESIONS AND FIBROSIS IN MICE

    Science.gov (United States)

    Smith, Jill P.; Cooper, Timothy K.; McGovern, Christopher O.; Gilius, Evan L.; Zhong, Qing; Liao, Jiangang; Molinolo, Alfredo A.; Gutkind, J. Silvio; Matters, Gail L.

    2014-01-01

    Objectives Exogenous administration of cholecystokinin (CCK) induces hypertrophy and hyperplasia of the pancreas with an increase in DNA content. We hypothesized that endogenous CCK is involved with the malignant progression of pancreatic intraepithelial neoplasia (PanIN) lesions and the fibrosis associated with pancreatic cancer. Methods The presence of CCK receptors in early PanIN lesions was examined by immunohistochemistry in mouse and human pancreas. Pdx1-Cre/LSL-KrasG12D transgenic mice were randomized to receive either untreated drinking water or water supplemented with a CCK-receptor antagonist (proglumide, 0.1mg/ml). Pancreas from mice were removed and examined histologically for number and grade of PanINs after 1, 2 or 4 months of antagonist therapy. Results Both CCK-A and CCK-B receptors were identified in early stage PanINs from mouse and human pancreas. The grade of PanIN lesions was reversed and progression to advanced lesions arrested in mice treated with proglumide compared to controls (p=0.004). Furthermore, pancreatic fibrosis was significantly reduced in antagonist-treated animals compared to vehicle (pitalic>0.001). Conclusions These findings demonstrate that endogenous CCK is in part responsible for the development and progression of pancreatic cancer. Use of CCK-receptor antagonists may have a role in cancer prophylaxis in high risk subjects, and may reduce fibrosis in the microenvironment. PMID:25058882

  7. Ancient DNA

    DEFF Research Database (Denmark)

    Willerslev, Eske; Cooper, Alan

    2004-01-01

    ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair......ancient DNA, palaeontology, palaeoecology, archaeology, population genetics, DNA damage and repair...

  8. Significance of localization of nonpalpable breast lesions

    Energy Technology Data Exchange (ETDEWEB)

    Oh, Ki Keun; Choi, Hyun Ju [Yongdong Severance Hospital, Yonsei University College of Medicine, Seoul (Korea, Republic of)

    1990-12-15

    As mammography has become more popular for the evaluation of breast symptoms and for the screening of asymptomatic women, the smaller lesions are being detected before they become palpable, therefore preoperative localization became necessary. This has led to the development of several methods for preoperative localization of nonpalpable lesions. Authors analyzed 50 cases with preoperative localization in 45 patients which had abnormal findings on film mammogram or ultrasonomammogram since October 1985 through March 1990 at Yongdong Severance Hospital, College of Medicine, Yonsei University. The results were as follows: 1. Techniques of localization were spot method in 8 cases, conventional needle localization method in 38 cases and Kopan's needle localization method in 4 cases. 2. The most common mammographic indication for localization was focal calcifications in 29 cases(58%), which was followed by a newly developed mass in 25 cases(50%). 3. Outcome of pathologically confirmed diagnosis put into benign lesions in 37 cases(74%) and malignant lesions in 13 cases(26%). 4. Among the cases with localization of lesions which has suggested as benign lesions in film and ultrasonomammogram,all cases(100%) were confirmed in benign lesions pathologically. Among the cases with localization of lesions which has suggested as malignant lesions in film and ultrasonomammogram, pathologic malignant has been proved of 44% and possible histopathologic precursor of malignant was resulted in 25% such as atypical hyperplasia and adenosis. Conclusively, authors consider that the abnormal areas should be removed in their entirety with the sacrifice of minimum volume of contiguous normal breast tissue through the preoperative localization, hence our preoperative localization has contributed favorable prognosis based on material lesions in early stage breast cancer.

  9. Significance of localization of nonpalpable breast lesions

    International Nuclear Information System (INIS)

    Oh, Ki Keun; Choi, Hyun Ju

    1990-01-01

    As mammography has become more popular for the evaluation of breast symptoms and for the screening of asymptomatic women, the smaller lesions are being detected before they become palpable, therefore preoperative localization became necessary. This has led to the development of several methods for preoperative localization of nonpalpable lesions. Authors analyzed 50 cases with preoperative localization in 45 patients which had abnormal findings on film mammogram or ultrasonomammogram since October 1985 through March 1990 at Yongdong Severance Hospital, College of Medicine, Yonsei University. The results were as follows: 1. Techniques of localization were spot method in 8 cases, conventional needle localization method in 38 cases and Kopan's needle localization method in 4 cases. 2. The most common mammographic indication for localization was focal calcifications in 29 cases(58%), which was followed by a newly developed mass in 25 cases(50%). 3. Outcome of pathologically confirmed diagnosis put into benign lesions in 37 cases(74%) and malignant lesions in 13 cases(26%). 4. Among the cases with localization of lesions which has suggested as benign lesions in film and ultrasonomammogram,all cases(100%) were confirmed in benign lesions pathologically. Among the cases with localization of lesions which has suggested as malignant lesions in film and ultrasonomammogram, pathologic malignant has been proved of 44% and possible histopathologic precursor of malignant was resulted in 25% such as atypical hyperplasia and adenosis. Conclusively, authors consider that the abnormal areas should be removed in their entirety with the sacrifice of minimum volume of contiguous normal breast tissue through the preoperative localization, hence our preoperative localization has contributed favorable prognosis based on material lesions in early stage breast cancer

  10. Enhanced radiosensitivity and defective DNA repair in cultured fibroblasts derived from Rothmund Thomson syndrome patients

    Energy Technology Data Exchange (ETDEWEB)

    Smith, P J; Paterson, M C [Atomic Energy of Canada Ltd., Chalk River, Ontario. Radiation Biology Branch

    1982-01-01

    Rothmund Thomson syndrome (RTS) is an oculocutaneous and cancer-prone disorder in which enhanced carcinogen sensitivity, mediated through abnormal DNA metabolism, may be an associated factor. Cultured fibroblasts from 4 RTS patients have been examined for their colony-forming abilities and DNA repair capacities following ..gamma..-irradiation. 2 of the 4 RTS strains showed enhanced sensitivity following hypoxic ..gamma..-irradiation, and 1 of these 2 strains also showed enhanced sensitivity under oxic conditions. Defective DNA repair was implicated in the above abnormal responses to ..gamma..-radiation since both strains displayed reduced levels of repair synthesis and slow removal of radiogenic DNA lesions (assayed by their sensitivity to strand-incising activities present in protein extracts of Micrococcus luteus cells). A hypothesis is presented to rationalize the origin and heterogeneity of these laboratory phenotypes of RTS.

  11. Repair of DNA in replicated and unreplicated portions of the human genome

    International Nuclear Information System (INIS)

    Waters, R.

    1979-01-01

    Portions of the human genome that have replicated after ultraviolet light irradiation and those that remain unreplicated have both been examined for the distribution of pyrimidine dimers and the extent of repair replication following their removal. The data indicate that the number of unrepaired dimers and the extent of repair replication seen after their excision are equal in the replicated and unreplicated DNA. Furthermore, the daughter strand of replicated DNA is larger than the average interdimer distance found in the parental strand. Hence, DNA replication in normal human fibroblasts is clearly capable of getting past pyrimidine dimers, and a preferential repair of such lesions in DNA that is about to be or has been replicated does not operate to any visible extent in these cells. (author)

  12. Nucleotide Excision Repair and Transcription-coupled DNA Repair Abrogate the Impact of DNA Damage on Transcription.

    Science.gov (United States)

    Nadkarni, Aditi; Burns, John A; Gandolfi, Alberto; Chowdhury, Moinuddin A; Cartularo, Laura; Berens, Christian; Geacintov, Nicholas E; Scicchitano, David A

    2016-01-08

    DNA adducts derived from carcinogenic polycyclic aromatic hydrocarbons like benzo[a]pyrene (B[a]P) and benzo[c]phenanthrene (B[c]Ph) impede replication and transcription, resulting in aberrant cell division and gene expression. Global nucleotide excision repair (NER) and transcription-coupled DNA repair (TCR) are among the DNA repair pathways that evolved to maintain genome integrity by removing DNA damage. The interplay between global NER and TCR in repairing the polycyclic aromatic hydrocarbon-derived DNA adducts (+)-trans-anti-B[a]P-N(6)-dA, which is subject to NER and blocks transcription in vitro, and (+)-trans-anti-B[c]Ph-N(6)-dA, which is a poor substrate for NER but also blocks transcription in vitro, was tested. The results show that both adducts inhibit transcription in human cells that lack both NER and TCR. The (+)-trans-anti-B[a]P-N(6)-dA lesion exhibited no detectable effect on transcription in cells proficient in NER but lacking TCR, indicating that NER can remove the lesion in the absence of TCR, which is consistent with in vitro data. In primary human cells lacking NER, (+)-trans-anti-B[a]P-N(6)-dA exhibited a deleterious effect on transcription that was less severe than in cells lacking both pathways, suggesting that TCR can repair the adduct but not as effectively as global NER. In contrast, (+)-trans-anti-B[c]Ph-N(6)-dA dramatically reduces transcript production in cells proficient in global NER but lacking TCR, indicating that TCR is necessary for the removal of this adduct, which is consistent with in vitro data showing that it is a poor substrate for NER. Hence, both global NER and TCR enhance the recovery of gene expression following DNA damage, and TCR plays an important role in removing DNA damage that is refractory to NER. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

  13. Non-surgical management of a chronic periapical lesion associated ...

    African Journals Online (AJOL)

    A case is reported of a chronic periapical lesion involving maxillary central incisors with a history of traumatic injury eight years previously and subsequent development of a painful swelling that occasionally caused partial blockage of the nasal cavities. Retrograde surgery for removal of the suspected cystic lesion was ...

  14. NEOPLASTIC LESIONS OF THE APPENDIX

    Directory of Open Access Journals (Sweden)

    Piotr Bryk

    2013-11-01

    Full Text Available The aim of the research was to present the clinical observations of neoplastic lesions of the appendix (one carcinoid and two mucous cysts and to discuss various manners of treatment and prognosis. Material and methods: The authors of the following paper present a description of three cases of appendix tumours, two patients with a mucous cyst and a patient with carcinoid, against the background of all the appendectomies performed at the Clinical Department of General, Endocrine and Oncological Surgery of the Provincial Polyclinical Hospital in Kielce in the years 2005–2011. Results : Within the 7-year period, a total of 11 719 surgical operations have been performed, where 834 (7.1% were that of appendectomy. Among all of the removed vermiform appendixes, neoplastic lesions occurred in three cases constituting a mere 0.3% of all of the appendectomies performed within that period. In two of the cases there was a suspicion of mucous cysts before the surgical operation. In none of the above-mentioned cases was is possible to ultimately establish the diagnosis before the operation. The patients were subjected to a simple appendectomy. The patients are in good clinical health, with no signs of relapse. Conclusions : The presented cases of patients with appendix tumours illustrate the difficulty of preoperative detection of a neoplastic lesion. This is mainly due to a scantily symptomatic course or symptoms typical of appendicitis. In light of this, histopathological examination of each appendix should be treated as obligatory.

  15. Size distribution of DNA molecules recovered from non-denaturing filter elution

    International Nuclear Information System (INIS)

    Bloecher, D.; Iliakis, G.

    1991-01-01

    DNA fragments removed from the filter during non-denaturing filter elution were collected and loaded on top of neutral sucrose gradients. Their size distribution was determined by low-speed centrifugation in neutral sucrose gradients. The average size of eluted DNA was found to be approximately 110 S; the average size of DNA collected after short elution times was found to be slightly larger than after long elution times. It is concluded that the size of eluted DNA fragments is not correlated with elution rate, and it is proposed that shear forces generated at the filter pores cause degradation of the DNA. Comparison of sedimentation profiles of carefully prepared cellular DNA before and after elution revealed that generated shear forces during elution break down DNA to an extent equivalent to around 20 000 DNA double-strand breaks (dsb) per G 1 cell. The size of DNA fragments decreased with increasing radiation dose; five times more dsb were found than expected after exposure to radiation alone. It is proposed that excess of dsb may derive from the transformation of other radiation-induced lesions to dsb under the action of shear forces generated during elution. (author)

  16. Variations in the spectrum of lesions produced in the DNA of cells from mouse tissues after exposure to γ-rays in air-breathing or in artificially anoxic animals

    International Nuclear Information System (INIS)

    Murray, D.; Meyn, R.E.; Vanankeren, S.C.

    1988-01-01

    Few DNA-protein crosslinks (dpc) were detected in the DNA from tumor cells γ-irradiated in vitro; however, in cells from both FSa and NFSa tumors irradiated in situ there was a significant level of protein-concealed ssb, and thus of dpc. These data are most likely the result of the relative hypoxia of a proportion of cells from both the FSa and NFSa tumor in the air-breathing animals. Induction of dpc was further enhanced in the DNA from tumor cells irradiated under anoxic conditions. A significant level of dpc was also observed in jejunal and spleen cells irradiated in vivo; however, since a significant level of protein-concealed breaks was also observed in cells irradiated in vitro, oxygenation appears not to be the only parameter capable of modifying the proportion of protein-concealed ssb, and the effects of proteinase K on the DNA elution rate for normal mouse tissues may be complex. (author)

  17. Repair of Clustered Damage and DNA Polymerase Iota.

    Science.gov (United States)

    Belousova, E A; Lavrik, O I

    2015-08-01

    Multiple DNA lesions occurring within one or two turns of the DNA helix known as clustered damage are a source of double-stranded DNA breaks, which represent a serious threat to the cells. Repair of clustered lesions is accomplished in several steps. If a clustered lesion contains oxidized bases, an individual DNA lesion is repaired by the base excision repair (BER) mechanism involving a specialized DNA polymerase after excising DNA damage. Here, we investigated DNA synthesis catalyzed by DNA polymerase iota using damaged DNA templates. Two types of DNA substrates were used as model DNAs: partial DNA duplexes containing breaks of different length, and DNA duplexes containing 5-formyluracil (5-foU) and uracil as a precursor of apurinic/apyrimidinic sites (AP) in opposite DNA strands. For the first time, we showed that DNA polymerase iota is able to catalyze DNA synthesis using partial DNA duplexes having breaks of different length as substrates. In addition, we found that DNA polymerase iota could catalyze DNA synthesis during repair of clustered damage via the BER system by using both undamaged and 5-foU-containing templates. We found that hPCNA (human proliferating cell nuclear antigen) increased efficacy of DNA synthesis catalyzed by DNA polymerase iota.

  18. Ghost cell lesions

    Directory of Open Access Journals (Sweden)

    E Rajesh

    2015-01-01

    Full Text Available Ghost cells have been a controversy for a long time. Ghost cell is a swollen/enlarged epithelial cell with eosnophilic cytoplasm, but without a nucleus. In routine H and E staining these cells give a shadowy appearance. Hence these cells are also called as shadow cells or translucent cells. The appearance of these cells varies from lesion to lesion involving odontogenic and nonodontogenic lesions. This article review about the origin, nature and significance of ghost cells in different neoplasms.

  19. Molecular Triage of Premalignant Lesions in Liquid-Based Cervical Cytology and Circulating Cell-Free DNA from Urine, Using a Panel of Methylated Human Papilloma Virus and Host Genes

    NARCIS (Netherlands)

    Guerrero-Preston, Rafael; Valle, Blanca L.; Jedlicka, Anne; Turaga, Nitesh; Folawiyo, Oluwasina; Pirini, Francesca; Lawson, Fahcina; Vergura, Angelo; Noordhuis, Maartje; Dziedzic, Amanda; Perez, Gabriela; Renehan, Marisa; Guerrero-Diaz, Carolina; Rodriguez, Edgar De Jesus; Diaz-Montes, Teresa; Orengo, Jose Rodriguez; Mendez, Keimari; Romaguera, Josefina; Trock, Bruce J.; Florea, Liliana; Sidransky, David

    2016-01-01

    Clinically useful molecular tools to triage women for a biopsy upon referral to colposcopy are not available. We aimed to develop a molecular panel to detect cervical intraepithelial neoplasia (CIN) grade 2 or higher lesions (CIN2(+)) in women with abnormal cervical cytology and high-risk HPV

  20. Aneuploidy in benign tumors and nonneoplastic lesions of musculoskeletal tissues.

    Science.gov (United States)

    Alho, A; Skjeldal, S; Pettersen, E O; Melvik, J E; Larsen, T E

    1994-02-15

    Aneuploidy in DNA flow cytometry (FCM) of musculoskeletal tumors is generally considered to be a sign of malignancy. Previously, giant cell tumor of the bone has been reported to contain aneuploid (near-diploid) DNA stemlines. Otherwise, only spordic cases have been reported. The authors wanted to study the relationships among DNA FCM, histology, and clinical course of nonmalignant musculoskeletal lesions. Twenty-eight histologically benign tumors and seven nonneoplastic lesions were subjected to DNA FCM: After tissue preparation mechanically and with ribonuclease and trypsin, the isolated nuclei were stained with propidium iodine using chicken and rainbow trout erythrocytes as controls. In the DNA FCM histograms, ploidy and cell cycle fractions were determined using a computerized mathematical model. The histologic diagnoses were made without knowledge of the DNA FCM results. Aneuploidy was found in eight lesions. A shoulder in the diploid peak, suggesting a diploid and a near-diploid population, was found in DNA histograms of a condensing osteitis of the clavicle (a benign inflammatory process) and of a giant cell tumor of bone. The latter lesion also had a tetraploid population. Six benign tumors--two enchondromas, one osteochondroma, one subcutaneous and one intramuscular lipoma, and a calcifying aponeurotic fibroma--showed clear aneuploidy with separate peaks. The S-phase fraction was less than 10% in all cases. The highest aneuploid population, DNA index = 1.70, in a subcutaneous lipoma, was small, with an undetectable S phase. Despite nonradical operations in seven lesions, no recurrences were observed during a median follow-up of 49 months (range, 28-73 months). Small aneuploid populations with low DNA synthetic activity may be compatible with a benign histologic picture and uneventful clinical course of the musculoskeletal lesion.

  1. Cellular responses to environmental DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    1994-08-01

    This volume contains the proceedings of the conference entitled Cellular Responses to Environmental DNA Damage held in Banff,Alberta December 1--6, 1991. The conference addresses various aspects of DNA repair in sessions titled DNA repair; Basic Mechanisms; Lesions; Systems; Inducible Responses; Mutagenesis; Human Population Response Heterogeneity; Intragenomic DNA Repair Heterogeneity; DNA Repair Gene Cloning; Aging; Human Genetic Disease; and Carcinogenesis. Individual papers are represented as abstracts of about one page in length.

  2. Alkyladenine DNA glycosylase (AAG) localizes to mitochondria and interacts with mitochondrial single-stranded binding protein (mtSSB).

    Science.gov (United States)

    van Loon, Barbara; Samson, Leona D

    2013-03-01

    Due to a harsh environment mitochondrial genomes accumulate high levels of DNA damage, in particular oxidation, hydrolytic deamination, and alkylation adducts. While repair of alkylated bases in nuclear DNA has been explored in detail, much less is known about the repair of DNA alkylation damage in mitochondria. Alkyladenine DNA glycosylase (AAG) recognizes and removes numerous alkylated bases, but to date AAG has only been detected in the nucleus, even though mammalian mitochondria are known to repair DNA lesions that are specific substrates of AAG. Here we use immunofluorescence to show that AAG localizes to mitochondria, and we find that native AAG is present in purified human mitochondrial extracts, as well as that exposure to alkylating agent promotes AAG accumulation in the mitochondria. We identify mitochondrial single-stranded binding protein (mtSSB) as a novel interacting partner of AAG; interaction between mtSSB and AAG is direct and increases upon methyl methanesulfonate (MMS) treatment. The consequence of this interaction is specific inhibition of AAG glycosylase activity in the context of a single-stranded DNA (ssDNA), but not a double-stranded DNA (dsDNA) substrate. By inhibiting AAG-initiated processing of damaged bases, mtSSB potentially prevents formation of DNA breaks in ssDNA, ensuring that base removal primarily occurs in dsDNA. In summary, our findings suggest the existence of AAG-initiated BER in mitochondria and further support a role for mtSSB in DNA repair. Copyright © 2012. Published by Elsevier B.V.

  3. Detection, characterization and measure of a new radiation-induced damage in isolated and cellular DNA

    International Nuclear Information System (INIS)

    Regulus, P.

    2006-10-01

    Deoxyribonucleic acid (DNA) contains the genetic information and chemical injury to this macromolecule may have severe biological consequences. We report here the detection of 4 new radiation-induced DNA lesions by using a high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) approach. For that purpose, the characteristic fragmentation of most 2'-deoxy-ribo nucleosides, the loss of 116 Da corresponding to the loss of the 2-deoxyribose moiety, was used in the so-called neutral loss mode of the HPLC-MS/MS. One of the newly detected lesions, named dCyd341 because it is a 2'-deoxycytidine modification exhibiting a molecular weight of 341 Da, was also detected in cellular DNA. Characterization of this modified nucleoside was performed using NMR and exact mass determination of the product obtained by chemical synthesis. A mechanism of formation was then proposed, in which the first event is the H-abstraction at the C4 position of a 2-deoxyribose moiety. Then, the sugar modification produced exhibits a reactive aldehyde that, through reaction with a vicinal cytosine base, gives rise to dCyd341. dCyd341 could be considered as a complex damage since its formation involves a DNA strand break and a cross-link between a damaged sugar residue and a vicinal cytosine base located most probably on the complementary DNA strand. In addition to its characterization, preliminary biological studies revealed that cells are able to remove the lesion from DNA. Repair studies have revealed the ability of cells to excise the lesion. Identification of the repair systems involved could represent an interesting challenge. (author)

  4. Enhanced base excision repair capacity in carotid atherosclerosis may protect nuclear DNA but not mitochondrial DNA

    DEFF Research Database (Denmark)

    Skarpengland, Tonje; B. Dahl, Tuva; Skjelland, Mona

    2016-01-01

    Lesional and systemic oxidative stress has been implicated in the pathogenesis of atherosclerosis, potentially leading to accumulation of DNA base lesions within atherosclerotic plaques. Although base excision repair (BER) is a major pathway counteracting oxidative DNA damage, our knowledge on BER...

  5. New insights in the removal of the hydantoins, oxidation product of pyrimidines, via the base excision and nucleotide incision repair pathways.

    Directory of Open Access Journals (Sweden)

    Modesto Redrejo-Rodríguez

    Full Text Available BACKGROUND: Oxidative damage to DNA, if not repaired, can be both miscoding and blocking. These genetic alterations can lead to mutations and/or cell death, which in turn cause cancer and aging. Oxidized DNA bases are substrates for two overlapping repair pathways: base excision (BER and nucleotide incision repair (NIR. Hydantoin derivatives such as 5-hydroxyhydantoin (5OH-Hyd and 5-methyl-5-hydroxyhydantoin (5OH-5Me-Hyd, major products of cytosine and thymine oxidative degradation pathways, respectively, have been detected in cancer cells and ancient DNA. Hydantoins are blocking lesions for DNA polymerases and excised by bacterial and yeast DNA glycosylases in the BER pathway. However little is known about repair of pyrimidine-derived hydantoins in human cells. METHODOLOGY/PRINCIPAL FINDINGS: Here, using both denaturing PAGE and MALDI-TOF MS analyses we report that the bacterial, yeast and human AP endonucleases can incise duplex DNA 5' next to 5OH-Hyd and 5OH-5Me-Hyd thus initiating the NIR pathway. We have fully reconstituted the NIR pathway for these lesions in vitro using purified human proteins. Depletion of Nfo in E. coli and APE1 in HeLa cells abolishes the NIR activity in cell-free extracts. Importantly, a number of redundant DNA glycosylase activities can excise hydantoin residues, including human NTH1, NEIL1 and NEIL2 and the former protein being a major DNA glycosylase activity in HeLa cells extracts. CONCLUSIONS/SIGNIFICANCE: This study demonstrates that both BER and NIR pathways can compete and/or back-up each other to remove hydantoin DNA lesions in vivo.

  6. Lesion activity assessment

    DEFF Research Database (Denmark)

    Ekstrand, K R; Zero, D T; Martignon, S

    2009-01-01

    in response to cariogenic plaque as well as lesion arrest. Based on this understanding, different clinical scoring systems have been developed to assess the severity/depth and activity of lesions. A recent system has been devised by the International Caries Detection and Assessment System Committee...

  7. Spleen removal

    Science.gov (United States)

    ... spleen. Sickle cell anemia . Splenic artery aneurysm (rare). Trauma to the spleen. Risks Risks for anesthesia and surgery in general ... removal - series References Brandow AM, Camitta BM. Hyposplenism, splenic trauma, and splenectomy. In: Kliegman RM, Stanton BF, St. ...

  8. Treatment of metastatic brain lesion

    Directory of Open Access Journals (Sweden)

    A. M. Zaytsev

    2015-01-01

    Full Text Available Objective. Increasing survival in patients with secondary brain damage, and identifying the factors of favorable and adverse prognosis.Material and method. In P. A. Hertsen Moscow Oncology Research Institute from 2007 to 2013 there were treated 268 patients with brain metastases. The mean age was 55.8 years (from 24 to 81 years. Metastases of colorectal cancer identified in 7.8%, cases of lung cancer in 34%, melanoma 9.3 %, breast cancer in 26%, kidney cancer in 11%, with non-identified primary tumor in 4.5%, other tumors accounted for 6.7%. Solitary metastasis was diagnosed in 164 (61,19% patients, oligometastasis (2-3 - 72 (26,87% patients with polymetastasis (more than 3 – 32 (11,94% patients. In 106 (39,55% of patients with brain metastases it was the only manifestation of the generalization process. To control the radical removal of the tumor in 93 (34,7% patients we used the method of fluorescence navigation (FN with the drug Alasens. In 66 (24,6% patients intraoperatively was held a session of photodynamic therapy (PDT. In 212 (79,1% cases, the removal of metastasis performed totally, 55 (20,9% patients stated Subtotal removal.Results. The observation period for the patients ranged from 3 to 79 months. Survival median among the entire group of patients with metastatic brain lesion was 12 months. Overall survival was significantly dependent on RPA class, the volume of postoperative treatment, histological type of primary tumor, number of intracerebral metastases and the timing of the relapse-free period.Conclusions. Factors that affects the overall survival are the features of the histology of the primary lesion, multiplicity of metastatic lesions, RPA class and the synchronous nature of the metastasis. The median of overall survival of patients who did not receive after surgical treatment of a particular type of therapy was only 4 months. If to use the combined treatment (surgical treatment with the irradiation of the whole brain median

  9. The DNA damage response during mitosis

    NARCIS (Netherlands)

    Heijink, Anne Margriet; Krajewska, Malgorzata; van Vugt, Marcel A. T. M.

    2013-01-01

    Cells are equipped with a cell-intrinsic signaling network called the DNA damage response (DDR). This signaling network recognizes DNA lesions and initiates various downstream pathways to coordinate a cell cycle arrest with the repair of the damaged DNA. Alternatively, the DDR can mediate clearance

  10. Role of dental restoration materials in oral mucosal lichenoid lesions

    Directory of Open Access Journals (Sweden)

    Rajneesh Sharma

    2015-01-01

    Full Text Available Background: Dental restorative materials containing silver-mercury compounds have been known to induce oral lichenoid lesions. Objectives: To determine the frequency of contact allergy to dental restoration materials in patients with oral lichenoid lesions and to study the effect of removal of the materials on the lesions. Results: Forty-five patients were recruited in three groups of 15 each: Group A (lesions in close contact with dental materials, Group B (lesions extending 1 cm beyond the area of contact and Group C (no topographic relationship. Thirty controls were recruited in two groups of 15 individuals each: Group D (oral lichenoid lesions but no dental material and Group E (dental material but no oral lichenoid lesions. Patch tests were positive in 20 (44.5% patients. Mercury was the most common allergen to elicit a positive reaction in eight patients, followed by nickel (7, palladium (5, potassium dichromate (3, balsam of Peru, gold sodium thiosulphate 2 and tinuvin (2 and eugenol (1, cobalt chloride (1 and carvone (1. Seven patients elicited positive response to more than one allergen. In 13 of 20 patients who consented to removal of the dental material, complete healing was observed in 6 (30%, marked improvement in 7 (35% and no improvement in 7 (35% patients. Relief of symptoms was usually observed 3 months after removal. Limitations: Limited number of study subjects and short follow up after removal/replacement of dental restoration materials are the main limitations of this study. Conclusion: Contact allergy to amalgam is an important etiologic factor in oral lichenoid lesions and removal of restorative material should be offered to patients who have lesions in close proximity to the dental material.

  11. Induction of DNA damage in γ-irradiated nuclei stripped of nuclear protein classes: differential modulation of double-strand break and DNA-protein crosslink formation

    International Nuclear Information System (INIS)

    Xue, L.-Y.; Friedman, L.R.; Oleinick, N.L.; Chiu, S.-M.

    1994-01-01

    The influence of chromatin proteins on the induction of DNA double-strand breaks (dsb) and DNA-protein crosslinks (dpc) by γ-radiation was investigated. Low molecular weight non-histone proteins and classes of histones were extracted with increasing concentrations of NaC1, whereas nuclear matrix proteins were not extractable even by 2.0 M NACl. The yield of dsb increased with progressive removal of proteins from chromatin. The data support our previous conclusion that nuclear matrix protein rather than the majority of the histones are the predominant substrates for dpc production, although the involvement of a subset of tightly bound histones (H3 and H4) has not been excluded. This finding demonstrates that chromatin proteins can differentially modify the yield of two types of radiation-induced DNA lesions. (author)

  12. Differential repair of platinum-DNA adducts in human bladder and testicular tumor continuous cell lines

    International Nuclear Information System (INIS)

    Bedford, P.; Fichtinger-Schepman, A.M.; Shellard, S.A.; Walker, M.C.; Masters, J.R.; Hill, B.T.

    1988-01-01

    The formation and removal of four platinum-DNA adducts were immunochemically quantitated in cultured cells derived from a human bladder carcinoma cell line (RT112) and from two lines derived from germ cell tumors of the testis (833K and SUSA), following exposure in vitro to 16.7 microM (5 micrograms/ml) cisplatin. RT112 cells were least sensitive to the drug and were proficient in the repair of all four adducts, whereas SUSA cells, which were 5-fold more sensitive, were deficient in the repair of DNA-DNA intrastrand cross-links in the sequences pApG and pGpG. Despite expressing a similar sensitivity to SUSA cells, 833K cells were proficient in the repair of all four adducts, although less so than the RT112 bladder tumor cells. In addition, SUSA cells were unable to repair DNA-DNA interstrand cross-links whereas 50-85% of these lesions were removed in RT112 and 833K cells 24 h following drug exposure. It is possible that the inability of SuSa cells to repair platinated DNA may account for their hypersensitivity to cisplatin

  13. Depletion of A-type lamins and Lap2α reduces 53BP1 accumulation at UV-induced DNA lesions and Lap2α protein is responsible for compactness of irradiated chromatin

    Czech Academy of Sciences Publication Activity Database

    Bártová, Eva; Legartová, Soňa; Krejčí, Jana; Řezníčková, Petra; Kovaříková, Alena; Suchánková, Jana; Fedr, Radek; Smirnov, E.; Hornáček, M.; Raška, I.

    2018-01-01

    Roč. 2018, č. 2018 (2018) ISSN 0730-2312 R&D Projects: GA ČR GBP302/12/G157; GA MŠk 7F14369 Institutional support: RVO:68081707 Keywords : DAPI * DNA damage response * FLIM Subject RIV: EB - Genetics ; Molecular Biology OBOR OECD: Cell biology Impact factor: 3.085, year: 2016

  14. Insights into the Structure of Intrastrand Cross-Link DNA Lesion-Containing Oligonucleotides: G[8-5m]T and G[8-5]C from Molecular Dynamics Simulations

    Czech Academy of Sciences Publication Activity Database

    Dumont, E.; Dršata, Tomáš; Guerra, C. F.; Lankaš, Filip

    2015-01-01

    Roč. 54, č. 5 (2015), s. 1259-1267 ISSN 0006-2960 R&D Projects: GA ČR(CZ) GA14-21893S Institutional support: RVO:61388963 Keywords : hydrogen bonds * abasic sites * duplex DNA Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.876, year: 2015

  15. Intraosseous osteolytic lesions

    Energy Technology Data Exchange (ETDEWEB)

    Adler, C.P.; Wenz, W.

    1981-10-01

    Any pathological damage occurring in a bone will produce either an osteolytic or osteosclerotic lesion which can be seen in the macroscopic specimen as well as in the roentgenogram. Various bone lesions may lead to local destructions of the bone. An osteoma or osteoplastic osteosarcoma produces an osteosclerotic lesion showing a dense mass in the roentgenogram; a chondroblastoma or an osteoclastoma, on the other hand, induces an osteolytic focal lesion. This paper presents examples of different osteolytic lesions of the humerus. An osteolytic lesion seen in the roentgenogram may be either produced by an underlying non-ossifying fibroma of the bone, by fibrous dysplasia, osteomyelitis or Ewing's sarcoma. Differential diagnostic considerations based on the radiological picture include eosinophilic bone granuloma, juvenile or aneurysmal bone cyst, multiple myeloma or bone metastases. Serious differential diagnostic problems may be involved in case of osteolytic lesions occurring in the humerus. Cases of this type involving complications have been reported and include the presence of an teleangiectatic osteosarcoma as well as that of a hemangiosarcoma of the bone.

  16. Xanthohumol, a prenylated flavonoid contained in beer, prevents the induction of preneoplastic lesions and DNA damage in liver and colon induced by the heterocyclic aromatic amine amino-3-methyl-imidazo[4,5-f]quinoline (IQ)

    International Nuclear Information System (INIS)

    Ferk, Franziska; Huber, Wolfgang W.; Filipic, Metka; Bichler, Julia; Haslinger, Elisabeth; Misik, Miroslav; Nersesyan, Armen; Grasl-Kraupp, Bettina; Zegura, Bojana; Knasmueller, Siegfried

    2010-01-01

    Xanthohumol (XN) is a hop derived prenylated flavonoid contained in beer. Earlier findings indicated that it has promising chemopreventive properties and protects cells against DNA damage by carcinogens via inhibition of their activation. Furthermore, it was found that XN inhibits DNA synthesis and proliferation of cancer cells in vitro, inactivates oxygen radicals and induces apoptosis. Since evidence for its chemoprotective properties is restricted to results from in vitro experiments, we monitored the impact of XN on the formation of amino-3-methyl-imidazo[4,5-f]quinoline (IQ)-induced preneoplastic foci in livers and colons of rats (9/group). Additionally, we studied its effects on IQ-induced DNA damage in colonocytes and hepatocytes in single cell gel electrophoresis assays and on the activities of a panel of drug metabolising enzymes. Consumption of the drinking water supplemented with XN (71 μg/kg b.w.) before and during carcinogen treatment led to a significant reduction of the number of GST-p + foci in the liver by 50% and also to a decrease of the foci area by 44%. DNA migration was decreased significantly in both, colon mucosa and liver cells, but no alterations of the activities of different phases I and II enzymes were found in hepatic tissue. Our findings indicate that XN protects against DNA damage and cancer induced by the cooked food mutagen. Since the effects were observed with low doses of XN which are reached after consumption of brews with high XN levels, our findings may be relevant for humans.

  17. Theory of pairwise lesion interaction

    International Nuclear Information System (INIS)

    Harder, Dietrich; Virsik-Peuckert, Patricia; Bartels, Ernst

    1992-01-01

    A comparison between repair time constants measured both at the molecular and cellular levels has shown that the DNA double strand break is the molecular change of key importance in the causation of cellular effects such as chromosome aberrations and cell inactivation. Cell fusion experiments provided the evidence that it needs the pairwise interaction between two double strand breaks - or more exactly between the two ''repair sites'' arising from them in the course of enzymatic repair - to provide the faulty chromatin crosslink which leads to cytogenetic and cytolethal effects. These modern experiments have confirmed the classical assumption of pairwise lesion interaction (PLI) on which the models of Lea and Neary were based. It seems worthwhile to continue and complete the mathematical treatment of their proposed mechanism in order to show in quantitative terms that the well-known fractionation, protraction and linear energy transfer (LET) irradiation effects are consequences of or can at least be partly attributed to PLI. Arithmetic treatment of PLI - a second order reaction - has also the advantage of providing a prerequisite for further investigations into the stages of development of misrepair products such as chromatin crosslinks. It has been possible to formulate a completely arithmetic theory of PLI by consequently applying three biophysically permitted approximations - pure first order lesion repair kinetics, dose-independent repair time constants and low yield of the ionization/lesion conversion. The mathematical approach will be summarized here, including several formulae not elaborated at the time of previous publications. We will also study an application which sheds light on the chain of events involved in PLI. (author)

  18. Study of ultraviolet light-induced DNA damage and repair: the role of the (6-4) photoproduct

    International Nuclear Information System (INIS)

    Franklin, W.A.

    1985-01-01

    Ultraviolet light induces lethal, mutagenic, and carcinogenic effects to cells. These effects are a result of the induction of photoproducts in the cellular DNA. One class of photoproducts was found as alkaline labile lesions in DNA, and it was proposed that such lesions were precursor products to the 6,4'-[pyrimidin-2'-one]-pyrimidine class of photoproducts that have been previously shown to occur in UV light-irradiated DNA. Using a series of dinucleotide compounds, the precursor compounds were isolated, and were demonstrated to be alkaline labile. These products were named the UV light-induced pyrimidine-pyrimidone (6-4) photoproducts, and their chemistry of formation in dinucleotides and DNA was studied. The formation of these photoproducts under conditions of chemical photosensitization was also measured. The most abundant of the (6-4) photoproducts is the thymine-cytosine (6-4) product, and the molecular structure of this compounds was determined by the use of infrared spectroscopy, proton NMR, and mass spectroscopy. The (6-4) products have been recently shown to be the major UV light-induced premutagenic lesions in E. coli. In E. coli, the repair of the (6-4) products is under the control of the uvrABC excision pathway. The rate of removal of (6-4) products was measured in a series of human cells lines. The rate of removal of (6-4) products from the DNA of a xeroderma pigmentosum complementation group A cell line was nearly that of the normal cells, yet these cells are unable to excise cyclobutane pyrimidine dimers. These results suggest that the removal of cyclobutane pyrimidine dimers and (6-4) products may be controlled by separate enzymatic pathways

  19. Effect of varying the exposure and 3H-thymidine labeling period upon the outcome of the primary hepatocyte DNA repair assay

    International Nuclear Information System (INIS)

    Barfknecht, T.R.; Mecca, D.J.; Naismith, R.W.

    1988-01-01

    The results presented in this report demonstrate that an 18-20 hour exposure/ 3 H-thymidine DNA labeling period is superior to a 4 hour incubation interval for general genotoxicity screening studies in the rat primary hepatocyte DNA repair assay. When DNA damaging agents which give rise to bulky-type DNA base adducts such as 2-acetylaminofluorene, aflatoxin B1 and benzidine were evaluated, little or no difference was observed between the 4 hour or an 18-20-hour exposure/labeling period. Similar results were also noted for the DNA ethylating agent diethylnitrosamine. However, when DNA damaging chemicals which produce a broader spectrum of DNA lesions were studied, differences in the amount of DNA repair as determined by autoradiographic analysis did occur. Methyl methanesulfonate and dimethylnitrosamine induced repairable DNA damage that was detected at lower dose levels with the 18-20 hour exposure/labeling period. Similar results were also observed for the DNA cross-linking agents, mitomycin C and nitrogen mustard. Ethyl methanesulfonate produced only a marginal amount of DNA repair in primary hepatocytes up to a dose level of 10(-3) M during the 4 hour incubation period, whereas a substantial amount of DNA repair was detectable at a dose level of 2.5 X 10(-4) M when the 18-20 hour exposure/labeling period was employed. The DNA alkylating agent 4-nitroquinoline-1-oxide, which creates DNA base adducts that are slowly removed from mammalian cell DNA, induced no detectable DNA repair in hepatocytes up to a toxic dose level of 2 X 10(-5) M with the 4 hour exposure period, whereas a marked DNA repair response was observed at 10(-5) M when the 18-20 hour exposure/labeling period was used

  20. Cavity lining after excavating caries lesions

    DEFF Research Database (Denmark)

    Schwendicke, Falk; Göstemeyer, Gerd; Gluud, Christian

    2015-01-01

    OBJECTIVES: After removal of dentin caries lesions, cavity lining has been advocated. Non-clinical data support this approach, but clinical data are sparse and ambiguous. We aimed at evaluating the benefits and harms of cavity lining using meta-analysis and Trial Sequential Analysis. DATA: We...... included randomized clinical trials comparing restorations without versus with cavity lining for treating primary caries lesions. Only trials reporting failure (defined as need to re-retreat) after ≥1 year follow-up were included. Trial selection, data extraction, and risk of bias assessment were conducted....... STUDY SELECTION: From 128 studies, three randomized trials (89/130 patients or teeth), all treating primary teeth, were included. The trials had high risk of bias. All trials compared no lining versus calcium hydroxide lining after selective caries removal followed by adhesive restoration. Follow...

  1. Diffuse cavitary lung lesions

    Energy Technology Data Exchange (ETDEWEB)

    Grunzke, Mindy; Garrington, Timothy [University of Colorado Denver, Department of Pediatrics, Aurora, CO (United States); The Children' s Hospital, Rick Wilson Center for Cancer and Blood Disorders, Aurora, CO (United States); Hayes, Kari [The Children' s Hospital, Pediatric Radiology, Aurora, CO (United States); Bourland, Wendy [Children' s Hospital at St. Francis, Warren Clinic, Inc., Tulsa, OK (United States)

    2010-02-15

    An 11-year-old girl presented with a 2-month history of progressively worsening cough, daily fevers, and weight loss. A chest radiograph revealed multiple cystic cavitary lung lesions. An extensive infectious work-up was negative. Chest CT verified multiple cavitary lung lesions bilaterally, and [F-18]2-fluoro-2-deoxy-D-glucose ({sup 18}F-FDG) positron emission tomography with CT (PET/CT) showed increased uptake in the lung lesions as well as regional lymph nodes. Subsequent biopsy of an involved lymph node confirmed classical Hodgkin lymphoma, nodular sclerosis type. This case represents an unusual presentation for a child with Hodgkin lymphoma and demonstrates a role for {sup 18}F-FDG PET/CT in evaluating a child with cavitary lung lesions. (orig.)

  2. Diffuse cavitary lung lesions

    International Nuclear Information System (INIS)

    Grunzke, Mindy; Garrington, Timothy; Hayes, Kari; Bourland, Wendy

    2010-01-01

    An 11-year-old girl presented with a 2-month history of progressively worsening cough, daily fevers, and weight loss. A chest radiograph revealed multiple cystic cavitary lung lesions. An extensive infectious work-up was negative. Chest CT verified multiple cavitary lung lesions bilaterally, and [F-18]2-fluoro-2-deoxy-D-glucose ( 18 F-FDG) positron emission tomography with CT (PET/CT) showed increased uptake in the lung lesions as well as regional lymph nodes. Subsequent biopsy of an involved lymph node confirmed classical Hodgkin lymphoma, nodular sclerosis type. This case represents an unusual presentation for a child with Hodgkin lymphoma and demonstrates a role for 18 F-FDG PET/CT in evaluating a child with cavitary lung lesions. (orig.)

  3. Uterine Vascular Lesions

    Science.gov (United States)

    Vijayakumar, Abhishek; Srinivas, Amruthashree; Chandrashekar, Babitha Moogali; Vijayakumar, Avinash

    2013-01-01

    Vascular lesions of the uterus are rare; most reported in the literature are arteriovenous malformations (AVMs). Uterine AVMs can be congenital or acquired. In recent years, there has been an increasing number of reports of acquired vascular lesions of the uterus following pregnancy, abortion, cesarean delivery, and curettage. It can be seen from these reports that there is confusion concerning the terminology of uterine vascular lesions. There is also a lack of diagnostic criteria and management guidelines, which has led to an increased number of unnecessary invasive procedures (eg, angiography, uterine artery embolization, hysterectomy for abnormal vaginal bleeding). This article familiarizes readers with various vascular lesions of the uterus and their management. PMID:24340126

  4. Hair Removal

    DEFF Research Database (Denmark)

    Hædersdal, Merete

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  5. Hair removal

    DEFF Research Database (Denmark)

    Haedersdal, Merete; Haak, Christina S

    2011-01-01

    Hair removal with optical devices has become a popular mainstream treatment that today is considered the most efficient method for the reduction of unwanted hair. Photothermal destruction of hair follicles constitutes the fundamental concept of hair removal with red and near-infrared wavelengths...... suitable for targeting follicular and hair shaft melanin: normal mode ruby laser (694 nm), normal mode alexandrite laser (755 nm), pulsed diode lasers (800, 810 nm), long-pulse Nd:YAG laser (1,064 nm), and intense pulsed light (IPL) sources (590-1,200 nm). The ideal patient has thick dark terminal hair......, white skin, and a normal hormonal status. Currently, no method of lifelong permanent hair eradication is available, and it is important that patients have realistic expectations. Substantial evidence has been found for short-term hair removal efficacy of up to 6 months after treatment with the available...

  6. Male breast lesions

    International Nuclear Information System (INIS)

    Matushita, J.P.K.; Andrade, L.G. de; Carregal, E.; Marimatsu, R.I.; Matushita, J.S.

    1989-01-01

    Roentgenographic examination of the male breast is an important aspect of the continued, intensive investigation of the radiologic morphology of the normal and diseased breast conducted in 17 cases examined at the Instituto Nacional do Cancer - RJ. It is purpose of this report to present the Roentgen appearance of various lesions of the male breast as they have been found in our practice and also to stress some of the difficulties in the differential diagnosis of these lesions. (author) [pt

  7. Tattoo removal with ingenol mebutate.

    Science.gov (United States)

    Cozzi, Sarah-Jane; Le, Thuy T; Ogbourne, Steven M; James, Cini; Suhrbier, Andreas

    2017-01-01

    An increasing number of people are getting tattoos; however, many regret the decision and seek their removal. Lasers are currently the most commonly used method for tattoo removal; however, treatment can be lengthy, costly, and sometimes ineffective, especially for certain colors. Ingenol mebutate is a licensed topical treatment for actinic keratoses. Here, we demonstrate that two applications of 0.1% ingenol mebutate can efficiently and consistently remove 2-week-old tattoos from SKH/hr hairless mice. Treatment was associated with relocation of tattoo microspheres from the dermis into the posttreatment eschar. The skin lesion resolved about 20 days after treatment initiation, with some cicatrix formation evident. The implications for using ingenol mebutate for tattoo removal in humans are discussed.

  8. Tattoo removal with ingenol mebutate

    Science.gov (United States)

    Cozzi, Sarah-Jane; Le, Thuy T; Ogbourne, Steven M; James, Cini; Suhrbier, Andreas

    2017-01-01

    An increasing number of people are getting tattoos; however, many regret the decision and seek their removal. Lasers are currently the most commonly used method for tattoo removal; however, treatment can be lengthy, costly, and sometimes ineffective, especially for certain colors. Ingenol mebutate is a licensed topical treatment for actinic keratoses. Here, we demonstrate that two applications of 0.1% ingenol mebutate can efficiently and consistently remove 2-week-old tattoos from SKH/hr hairless mice. Treatment was associated with relocation of tattoo microspheres from the dermis into the posttreatment eschar. The skin lesion resolved about 20 days after treatment initiation, with some cicatrix formation evident. The implications for using ingenol mebutate for tattoo removal in humans are discussed. PMID:28579816

  9. Benign fibroosseous lesions

    Directory of Open Access Journals (Sweden)

    Cansu Köseoğlu Seçgin

    2016-05-01

    Full Text Available Benign fibroosseous lesions represent a group of lesions that share the same basic evolutive mechanism and are characterized by replacement of normal bone with a fibrous connective tissue that gradually undergoes mineralization. These lesions are presented by a variety of diseases including developmental, reactive-dysplastic processes and neoplasms. Depending on the nature and amount of calcified tissue, they can be observed as radiolucent, mixed or radiopaque. Their radiographic features could be well-defined or indistinguishable from the surrounding bone tissue. They can be asymptomatic as in osseous dysplasias and can be detected incidentally on radiographs, or they can lead to expansion in the affected bone as in ossifying fibroma. All fibroosseous lesions seen in the jaws and face are variations of the same histological pattern. Therefore, detailed clinical and radiographic evaluation in differential diagnosis is important. In this review, fibroosseous benign lesions are classified as osseous dysplasia, fibrous dysplasia and fibroosseous tumors; and radiographic features and differential diagnosis of these lesions are reviewed taking into account this classification.

  10. PREVALENCE OF HUMAN PAPILLOMAVIRUS GENOTYPES IN LOW AND HIGH GRADE SQUAMOUS INTRAEPITHELIAL LESIONS AT CERVICAL TISSUE

    OpenAIRE

    Prasetyo, Rizki Eko; Mastutik, Gondo; Mustokoweni, Sjahjenny

    2017-01-01

    HPV infection is known to cause cervical cancer. This study aimed to identify the variant of HPV genotypes of cervical precancerous lesions from low grade squamous intraepithelial lesion  (LSIL) and high grade squamous intraepithelial lesion (HSIL). This was an explorative study using formalin fix paraffin embedded (FFPE) from cervical precancerous lesions at Dr. Soetomo Hospital, Surabaya. DNA was extracted from FFPE and hybridized for HPV genotyping using Ampliquality HPV Type Express kit (...

  11. Ada response - a strategy for repair of alkylated DNA in bacteria.

    Science.gov (United States)

    Mielecki, Damian; Grzesiuk, Elżbieta

    2014-06-01

    Alkylating agents are widespread in the environment and also occur endogenously. They can be cytotoxic or mutagenic to the cells introducing alkylated bases to DNA or RNA. All organisms have evolved multiple DNA repair mechanisms to counteract the effects of DNA alkylation: the most cytotoxic lesion, N(3)-methyladenine (3meA), is excised by AlkA glycosylase initiating base excision repair (BER); toxic N(1)-methyladenine (1meA) and N(3)-methylcytosine (3meC), induced in DNA and RNA, are removed by AlkB dioxygenase; and mutagenic and cytotoxic O(6)-methylguanine (O(6) meG) is repaired by Ada methyltransferase. In Escherichia coli, Ada response involves the expression of four genes, ada, alkA, alkB, and aidB, encoding respective proteins Ada, AlkA, AlkB, and AidB. The Ada response is conserved among many bacterial species; however, it can be organized differently, with diverse substrate specificity of the particular proteins. Here, an overview of the organization of the Ada regulon and function of individual proteins is presented. We put special effort into the characterization of AlkB dioxygenases, their substrate specificity, and function in the repair of alkylation lesions in DNA/RNA. © 2014 The Authors. FEMS Microbiology Letters published by John Wiley & Sons Ltd on behalf of Federation of European Microbiological Societies.

  12. Ada response – a strategy for repair of alkylated DNA in bacteria

    Science.gov (United States)

    Mielecki, Damian; Grzesiuk, Elżbieta

    2014-01-01

    Alkylating agents are widespread in the environment and also occur endogenously. They can be cytotoxic or mutagenic to the cells introducing alkylated bases to DNA or RNA. All organisms have evolved multiple DNA repair mechanisms to counteract the effects of DNA alkylation: the most cytotoxic lesion, N3-methyladenine (3meA), is excised by AlkA glycosylase initiating base excision repair (BER); toxic N1-methyladenine (1meA) and N3-methylcytosine (3meC), induced in DNA and RNA, are removed by AlkB dioxygenase; and mutagenic and cytotoxic O6-methylguanine (O6meG) is repaired by Ada methyltransferase. In Escherichia coli, Ada response involves the expression of four genes, ada, alkA, alkB, and aidB, encoding respective proteins Ada, AlkA, AlkB, and AidB. The Ada response is conserved among many bacterial species; however, it can be organized differently, with diverse substrate specificity of the particular proteins. Here, an overview of the organization of the Ada regulon and function of individual proteins is presented. We put special effort into the characterization of AlkB dioxygenases, their substrate specificity, and function in the repair of alkylation lesions in DNA/RNA. PMID:24810496

  13. Processing of UV-induced DNA damage in diverse biological systems

    International Nuclear Information System (INIS)

    Galloway, A.M.

    1992-01-01

    A novel protocol has been developed allowing direct evaluation and accurate quantitation of UV lesions contained with both genomic DNA and the small oligonucleotides excised by a living cell during nucleotide excision repair. Using this methodology, the repair capacity of normal and UV-sensitive cells of human, Chinese hamster, and Escherichia coli origin, has been assessed. Several conclusions have been reached: (1) severage of the interpyrimidine phosphodiester linkage of cyclobutane dimers appears to be an evolutionarily conserved phenomenon; (2) the kinetics of cyclobutane dimer repair differ markedly from both (6-4) photoproduct and TA* lesion removal; (3) the ability to excise cyclobutane dimers is independent of (6-4) photoproduct repair capacity, suggesting that the lesions are not repaired/recognized by identical mechanisms; (4) fibroblast strains representing the eight xeroderma pigmentosum complementation groups each show a unique proficiency/deficiency to repair the different photolesions under study, implicating that a defect in a different locus underlies each genetic form of this disease; (5) the repair deficiency in UV-sensitive strains of trichothiodystrophy appears to be completely unrelated to that of non-complementing XP-D cells. To allow direct assessment of an IDP-altered photoproduct, substrates have been constructed which contain, at a defined dithymidine site, no lesion, a conventional cyclobutane dimer, or a cyclobutane dimer modified by severage of the intradimer phosphodiester bond. Bacteriophage T4 UV endonuclease has no activity towards a modified lesion, questioning the interpretation of experiments which utilize the strand-incising activity of this enzyme to monitor repair. Furthermore, although this altered lesion acts as a block to E. coli DNA polymerase I, it allows SP6 RNA polymerase to bypass the otherwise RNA polymerase-blocking lesion

  14. Use of human papillomavirus DNA, E6/E7 mRNA, and p16 immunocytochemistry to detect and predict anal high-grade squamous intraepithelial lesions in HIV-positive and HIV-negative men who have sex with men.

    Directory of Open Access Journals (Sweden)

    Nittaya Phanuphak

    Full Text Available Men who have sex with men (MSM are at high risk of having anal cancer. Anal high-grade squamous intraepithelial lesion (HSIL is the precursor of anal cancer. We explored the use of different biomarkers associated with human papillomavirus (HPV infection and HPV-mediated cell transformation to detect and predict HSIL among HIV-positive and HIV-negative MSM.A total of 123 HIV-positive and 123 HIV-negative MSM were enrolled and followed for 12 months. High-resolution anoscopy (HRA with biopsies were performed at every visit along with anal sample collection for cytology, high-risk HPV DNA genotyping, HPV E6/E7 mRNA, and p16 immunocytochemistry. Performance characteristics and area under the receiver operator characteristics curve were calculated for these biomarkers at baseline, and Cox regression compared the usefulness of these biomarkers in predicting incident HSIL. High-risk HPV DNA, E6/E7 mRNA, and p16 immunocytochemistry each identified 43-46% of MSM whose baseline test positivity would trigger HRA referral. E6/E7 mRNA had the highest sensitivity (64.7% and correctly classified the highest number of prevalent HSIL cases. With the exception of p16 immunochemistry, most tests showed significant increases in sensitivity but decreases specificity versus anal cytology, while the overall number of correctly classified cases was not significantly different. Baseline or persistent type 16 and/or 18 HPV DNA was the only test significantly predicting incident histologic HSIL within 12 months in models adjusted for HIV status and low-grade squamous intraepithelial lesions at baseline.Countries with a high HIV prevalence among MSM and limited HRA resources may consider using biomarkers to identify individuals at high risk of HSIL. E6/E7 mRNA had the highest sensitivity for prevalent HSIL detection regardless of HIV status, whereas type 16 and/or 18 HPV DNA performed best in predicting development of incident HSIL within 12 months.

  15. Tumor‐associated DNA mutation detection in individuals undergoing colonoscopy

    OpenAIRE

    Fleshner, Phillip; Braunstein, Glenn D.; Ovsepyan, Gayane; Tonozzi, Theresa R.; Kammesheidt, Anja

    2017-01-01

    Abstract The majority of colorectal cancers (CRC) harbor somatic mutations and epigenetic modifications in the tumor tissue, and some of these mutations can be detected in plasma as circulating tumor DNA (ctDNA). Precancerous colorectal lesions also contain many of these same mutations. This study examined plasma for ctDNA from patients undergoing a screening or diagnostic colonoscopy to determine the sensitivity and specificity of the ctDNA panel for detecting CRC and precancerous lesions. T...

  16. The Role of XPG in Processing (CAGn/(CTGn DNA Hairpins

    Directory of Open Access Journals (Sweden)

    Hou Caixia

    2011-03-01

    Full Text Available Abstract Background During DNA replication or repair, disease-associated (CAGn/(CTGn expansion can result from formation of hairpin structures in the repeat tract of the newly synthesized or nicked DNA strand. Recent studies identified a nick-directed (CAGn/(CTGn hairpin repair (HPR system that removes (CAGn/(CTGn hairpins from human cells via endonucleolytic incisions. Because the process is highly similar to the mechanism by which XPG and XPF endonucleases remove bulky DNA lesions during nucleotide excision repair, we assessed the potential role of XPG in conducting (CAGn/(CTGn HPR. Results To determine if the XPG endonuclease is involved in (CAGn/(CTGn hairpin removal, two XPG-deficient cell lines (GM16024 and AG08802 were examined for their ability to process (CAGn/(CTGn hairpins in vitro. We demonstrated that the GM16024 cell line processes all hairpin substrates as efficiently as HeLa cells, and that the AG08802 cell line is partially defective in HPR. Analysis of repair intermediates revealed that nuclear extracts from both XPG-deficient lines remove CAG/CTG hairpins via incisions, but the incision products are distinct from those generated in HeLa extracts. We also show that purified recombinant XPG protein greatly stimulates HPR in XPG-deficient extracts by promoting an incision 5' to the hairpin. Conclusions Our results strongly suggest that 1 human cells possess multiple pathways to remove (CAGn/(CTGn hairpins located in newly synthesized (or nicked DNA strand; and 2 XPG, although not essential for (CAGn/(CTGn hairpin removal, stimulates HPR by facilitating a 5' incision to the hairpin. This study reveals a novel role for XPG in genome-maintenance and implicates XPG in diseases caused by trinucleotide repeat expansion.

  17. DNA damage and repair in plants

    International Nuclear Information System (INIS)

    Britt, A.B.

    1996-01-01

    The biological impact of any DNA damaging agent is a combined function of the chemical nature of the induced lesions and the efficiency and accuracy of their repair. Although much has been learned frommicrobes and mammals about both the repair of DNA damage and the biological effects of the persistence of these lesions, much remains to be learned about the mechanism and tissue-specificity of repair in plants. This review focuses on recent work on the induction and repair of DNA damage in higher plants, with special emphasis on UV-induced DNA damage products. (author)

  18. Lasers and intense pulsed light (IPL) association with cancerous lesions.

    Science.gov (United States)

    Ash, Caerwyn; Town, Godfrey; Whittall, Rebecca; Tooze, Louise; Phillips, Jaymie

    2017-11-01

    The development and use of light and lasers for medical and cosmetic procedures has increased exponentially over the past decade. This review article focuses on the incidence of reported cases of skin cancer post laser or IPL treatment. The existing evidence base of over 25 years of laser and IPL use to date has not raised any concerns regarding its long-term safety with only a few anecdotal cases of melanoma post treatment over two decades of use; therefore, there is no evidence to suggest that there is a credible cancer risk. Although laser and IPL technology has not been known to cause skin cancer, this does not mean that laser and IPL therapies are without long-term risks. Light therapies and lasers to treat existing lesions and CO 2 laser resurfacing can be a preventative measure against BCC and SCC tumour formation by removing photo-damaged keratinocytes and encouraged re-epithelisation from stem cells located deeper in the epidermis. A review of the relevant literature has been performed to address the issue of long-term IPL safety, focussing on DNA damage, oxidative stress induction and the impact of adverse events.

  19. Removing Bureaucracy

    Science.gov (United States)

    2015-08-01

    11 Defense AT&L: July–August 2015 Removing Bureaucracy Katharina G. McFarland McFarland is Assistant Secretary of Defense for Acquisition. I once...involvement from all of the Service warfighting areas came together to scrub the program requirements due to concern over the “ bureaucracy ” and... Bureaucracy ” that focuses on reducing cycle time, staffing time and all forms of inefficiencies. This includes review of those burdens that Congress

  20. Human papillomavirus in oral lesions Virus papiloma humano en lesiones orales

    Directory of Open Access Journals (Sweden)

    Joaquín V. Gónzalez

    2007-08-01

    Full Text Available Growing evidence suggests a role for human papillomavirus (HPV in oral cancer; however its involvement is still controversial. This study evaluates the frequency of HPV DNA in a variety of oral lesions in patients from Argentina. A total of 77 oral tissue samples from 66 patients were selected (cases; the clinical-histopathological diagnoses corresponded to: 11 HPV- associated benign lesions, 8 non-HPV associated benign lesions, 33 premalignant lesions and 25 cancers. Sixty exfoliated cell samples from normal oral mucosa were used as controls. HPV detection and typing were performed by polymerase chain reaction (PCR using primers MY09, 11, combined with RFLP or alternatively PCR using primers GP5+, 6+ combined with dot blot hybridization. HPV was detected in 91.0% of HPV- associated benign lesions, 14.3% of non-HPV associated benign lesions, 51.5% of preneoplasias and 60.0% of cancers. No control sample tested HPV positive. In benign HPV- associated lesions, 30.0% of HPV positive samples harbored high-risk types, while in preneoplastic lesions the value rose to 59.9%. In cancer lesions, HPV detection in verrucous carcinoma was 88.9% and in squamous cell carcinoma 43.8%, with high-risk type rates of 75.5% and 85.6%, respectively. The high HPV frequency detected in preneoplastic and neoplastic lesions supports an HPV etiological role in at least a subset of oral cancers.Crecientes evidencias sugieren que el virus Papiloma humano (HPV tiene un rol en el cáncer oral; sin embargo su participación es todavía controvertida. Este estudio evalúa la frecuencia de ADN de HPV en una variedad de lesiones orales de pacientes de Argentina. Se seleccionaron 77 muestras de tejido oral de 66 pacientes (casos; el diagnóstico histo-patológico correspondió a: 11 lesiones benignas asociadas a HPV, 8 lesiones benignas no asociadas a HPV, 33 lesiones premalignas y 25 cánceres. Como controles se usaron 60 muestras de células exfoliadas de mucosa oral normal. La

  1. Precancerous Skin Lesions.

    Science.gov (United States)

    Ferrándiz, C; Malvehy, J; Guillén, C; Ferrándiz-Pulido, C; Fernández-Figueras, M

    Certain clinically and histologically recognizable skin lesions with a degree of risk of progression to squamous cell carcinoma have been traditionally grouped as precancerous skin conditions but now tend to be classified as in situ carcinomas. This consensus statement discusses various aspects of these lesions: their evaluation by means of clinical and histopathologic features, the initial evaluation of the patient, the identification of risk factors for progression, and the diagnostic and treatment strategies available today. Copyright © 2016 AEDV. Publicado por Elsevier España, S.L.U. All rights reserved.

  2. DNA damage and polyploidization.

    Science.gov (United States)

    Chow, Jeremy; Poon, Randy Y C

    2010-01-01

    A growing body of evidence indicates that polyploidization triggers chromosomal instability and contributes to tumorigenesis. DNA damage is increasingly being recognized for its roles in promoting polyploidization. Although elegant mechanisms known as the DNA damage checkpoints are responsible for halting the cell cycle after DNA damage, agents that uncouple the checkpoints can induce unscheduled entry into mitosis. Likewise, defects of the checkpoints in several disorders permit mitotic entry even in the presence of DNA damage. Forcing cells with damaged DNA into mitosis causes severe chromosome segregation defects, including lagging chromosomes, chromosomal fragments and chromosomal bridges. The presence of these lesions in the cleavage plane is believed to abort cytokinesis. It is postulated that if cytokinesis failure is coupled with defects of the p53-dependent postmitotic checkpoint pathway, cells can enter S phase and become polyploids. Progress in the past several years has unraveled some of the underlying principles of these pathways and underscored the important role of DNA damage in polyploidization. Furthermore, polyploidization per se may also be an important determinant of sensitivity to DNA damage, thereby may offer an opportunity for novel therapies.

  3. Common conjunctival lesions

    African Journals Online (AJOL)

    Conjunctival lesions are frequently seen in the eye clinic, because the conjunctiva is readily ... anti-histamine drops and mast cell stabilisers can be used. e more severe cases have to be .... Ehlers J, Shah C . The Wills Eye Manual. Office and.

  4. Genital lesions following bestiality

    Directory of Open Access Journals (Sweden)

    Mittal A

    2000-01-01

    Full Text Available A 48-year-old man presented with painful genital lesions with history of bestiality and abnor-mal sexual behaviour. Examination revealed multiple irregular tender ulcers and erosions, with phimosis and left sided tender inguinal adenopathy. VDRL, TPHA, HIV-ELISA were negative. He was treated with ciprofloxacin 500mg b.d. along with saline compresses with complete resolution.

  5. Semi-automated Robust Quantification of Lesions (SRQL Toolbox

    Directory of Open Access Journals (Sweden)

    Kaori L Ito

    2017-05-01

    Full Text Available Quantifying lesions in a reliable manner is fundamental for studying the effects of neuroanatomical changes related to recovery in the post-stroke brain. However, the wide variability in lesion characteristics across individuals makes manual lesion segmentation a challenging and often subjective process. This often makes it difficult to combine stroke lesion data across multiple research sites, due to subjective differences in how lesions may be defined. Thus, we developed the Semi-automated Robust Quantification of Lesions (SRQL; https://github.com/npnl/SRQL; DOI: 10.5281/zenodo.557114 Toolbox that performs several analysis steps: 1 a white matter intensity correction that removes healthy white matter voxels from the lesion mask, thereby making lesions slightly more robust to subjective errors; 2 an automated report of descriptive statistics on lesions for simplified comparison between or across groups, and 3 an option to perform analyses in both native and standard space to facilitate analyses in either space. Here, we describe the methods implemented in the toolbox.

  6. Semi-automated Robust Quantification of Lesions (SRQL Toolbox

    Directory of Open Access Journals (Sweden)

    Kaori Ito

    2017-02-01

    Full Text Available Quantifying lesions in a robust manner is fundamental for studying the effects of neuroanatomical changes in the post-stroke brain on recovery. However, the wide variability in lesion characteristics across individuals makes manual lesion segmentation a challenging and often subjective process. This makes it difficult to combine stroke lesion data across multiple research sites, due to subjective differences in how lesions may be defined. We developed the Semi-automated Robust Quantification of Lesions (SRQL; https://github.com/npnl/SRQL; DOI: 10.5281/zenodo.267213 Toolbox that performs several analysis steps: 1 a white matter intensity correction that removes healthy white matter voxels from the lesion mask, thereby making lesions slightly more robust to subjective errors; 2 an automated report of descriptive statistics on lesions for simplified comparison between or across groups, and 3 an option to perform analyses in both native and standard space to facilitate analyses in either space, or comparisons between spaces. Here, we describe the methods implemented in the toolbox and demonstrate the outputs of the SRQL toolbox.

  7. Milk removal

    OpenAIRE

    Ferneborg, Sabine

    2016-01-01

    Milk from dairy cows is a staple dietary component for humans all over the world. Regardless of whether milk is consumed in its purest, unaltered form or as high-end products such as fine cheese or ice cream, it needs to be of high quality when taken from the cow, produced at a low price and produced in a system that consider aspects such as animal health, animal welfare and sustainability. This thesis investigated the role of milk removal and the importance of residual milk on milk yield...

  8. Modes of DNA repair and replication

    International Nuclear Information System (INIS)

    Hanawalt, P.; Kondo, S.

    1979-01-01

    Modes of DNA repair and replication require close coordination as well as some overlap of enzyme functions. Some classes of recovery deficient mutants may have defects in replication rather than repair modes. Lesions such as the pyrimidine dimers produced by ultraviolet light irradiation are the blocks to normal DNA replication in vivo and in vitro. The DNA synthesis by the DNA polymerase 1 of E. coli is blocked at one nucleotide away from the dimerized pyrimidines in template strands. Thus, some DNA polymerases seem to be unable to incorporate nucleotides opposite to the non-pairing lesions in template DNA strands. The lesions in template DNA strands may block the sequential addition of nucleotides in the synthesis of daughter strands. Normal replication utilizes a constitutive ''error-free'' mode that copies DNA templates with high fidelity, but which may be totally blocked at a lesion that obscures the appropriate base pairing specificity. It might be expected that modified replication system exhibits generally high error frequency. The error rate of DNA polymerases may be controlled by the degree of phosphorylation of the enzyme. Inducible SOS system is controlled by recA genes that also control the pathways for recombination. It is possible that SOS system involves some process other than the modification of a blocked replication apparatus to permit error-prone transdimer synthesis. (Yamashita, S.)

  9. Morel-Lavallee lesion.

    Science.gov (United States)

    Li, Hui; Zhang, Fangjie; Lei, Guanghua

    2014-01-01

    To review current knowledge of the Morel-Lavallee lesion (MLL) to help clinicians become familiar with this entity. Familiarization may decrease missed diagnoses and misdiagnoses. It could also help steer the clinician to the proper treatment choice. A search was performed via PubMed and EMBASE from 1966 to July 2013 using the following keywords: Morel-Lavallee lesion, closed degloving injury, concealed degloving injury, Morel-Lavallee effusion, Morel-Lavallee hematoma, posttraumatic pseudocyst, posttraumatic soft tissue cyst. Chinese and English language literatures relevant to the subject were collected. Their references were also reviewed. Morel-Lavallee lesion is a relatively rare condition involving a closed degloving injury. It is characterized by a filled cystic cavity created by separation of the subcutaneous tissue from the underlying fascia. Apart from the classic location over the region of the greater trochanter, MLLs have been described in other parts of the body. The natural history of MLL has not yet been established. The lesion may decrease in volume, remain stable, enlarge progressively or show a recurrent pattern. Diagnosis of MLL was often missed or delayed. Ultrasonography, computed tomography, and magnetic resonance imaging have great value in the diagnosis of MLL. Treatment of MLL has included compression, local aspiration, open debridement, and sclerodesis. No standard treatment has been established. A diagnosis of MLL should be suspected when a soft, fluctuant area of skin or chronic recurrent fluid collection is found in a region exposed to a previous shear injury. Clinicians and radiologists should be aware of both the acute and chronic appearances to make the correct diagnosis. Treatment decisions should base on association with fractures, the condition of the lesion, symptom and desire of the patient.

  10. Maxillomandibular giant osteosclerotic lesions

    Directory of Open Access Journals (Sweden)

    Constantino LEDESMA-MONTES

    2018-06-01

    Full Text Available Abstract Giant Osteosclerotic Lesions (GOLs are a group of rarely reported intraosseous lesions. Their precise diagnosis is important since they can be confused with malignant neoplasms. Objective This retrospective study aimed to record and analyze the clinical and radiographic Giant Osteosclerotic Lesions (GOLs detected in the maxillomandibular area of patients attending to our institution. Materials and Methods: Informed consent from the patients was obtained and those cases of 2.5 cm or larger lesions with radiopaque or mixed (radiolucid-radiopaque appearance located in the maxillofacial bones were selected. Assessed parameters were: age, gender, radiographic aspect, shape, borders, size, location and relations to roots. Lesions were classified as radicular, apical, interradicular, interradicular-apical, radicular-apical or located in a previous teeth extraction area. Additionally, several osseous and dental developmental alterations (DDAs were assessed. Results Seventeen radiopacities in 14 patients were found and were located almost exclusively in mandible and were two types: idiopathic osteosclerosis and condensing osteitis. GOLs were more frequent in females, and in the anterior and premolar zones. 94.2% of GOLs were qualified as idiopathic osteosclerosis and one case was condensing osteitis. All studied cases showed different osseous and dental developmental alterations (DDAs. The most common were: Microdontia, hypodontia, pulp stones, macrodontia and variations in the mental foramina. Conclusions GOLs must be differentiated from other radiopaque benign and malignant tumors. Condensing osteitis, was considered an anomalous osseous response induced by a chronic low-grade inflammatory stimulus. For development of idiopathic osteosclerosis, two possible mechanisms could be related. The first is modification of the normal turnover with excessive osseous deposition. The second mechanism will prevent the normal bone resorption, arresting the

  11. Chemotherapeutic Drugs: DNA Damage and Repair in Glioblastoma.

    Science.gov (United States)

    Annovazzi, Laura; Mellai, Marta; Schiffer, Davide

    2017-05-26

    Despite improvements in therapeutic strategies, glioblastoma (GB) remains one of the most lethal cancers. The presence of the blood-brain barrier, the infiltrative nature of the tumor and several resistance mechanisms account for the failure of current treatments. Distinct DNA repair pathways can neutralize the cytotoxicity of chemo- and radio-therapeutic agents, driving resistance and tumor relapse. It seems that a subpopulation of stem-like cells, indicated as glioma stem cells (GSCs), is responsible for tumor initiation, maintenance and recurrence and they appear to be more resistant owing to their enhanced DNA repair capacity. Recently, attention has been focused on the pivotal role of the DNA damage response (DDR) in tumorigenesis and in the modulation of therapeutic treatment effects. In this review, we try to summarize the knowledge concerning the main molecular mechanisms involved in the removal of genotoxic lesions caused by alkylating agents, emphasizing the role of GSCs. Beside their increased DNA repair capacity in comparison with non-stem tumor cells, GSCs show a constitutive checkpoint expression that enables them to survive to treatments in a quiescent, non-proliferative state. The targeted inhibition of checkpoint/repair factors of DDR can contribute to eradicate the GSC population and can have a great potential therapeutic impact aiming at sensitizing malignant gliomas to treatments, improving the overall survival of patients.

  12. LET-effects in DNA

    International Nuclear Information System (INIS)

    Kraft, G.; Taucher-Scholz, G.; Heilmann, J.

    1994-11-01

    In this contribution, an introductory view on the physical properties of ions is given and the cellular response to high LET radiation is summarized. Then the measurements of strand break induction of DNA in solution and in intracellular DNA are reported and compared to cell survival. The possibility of changes in the quality of the lesions is discussed and finally the present status of model calculations in comparison to the experiments is given. (orig./HSI)

  13. Surgical treatment of patients with single and dual pathology: relevance of lesion and of hippocampal atrophy to seizure outcome.

    Science.gov (United States)

    Li, L M; Cendes, F; Watson, C; Andermann, F; Fish, D R; Dubeau, F; Free, S; Olivier, A; Harkness, W; Thomas, D G; Duncan, J S; Sander, J W; Shorvon, S D; Cook, M J; Arnold, D L

    1997-02-01

    Modern neuroimaging can disclose epileptogenic lesions in many patients with partial epilepsy and, at times, display the coexistence of hippocampal atrophy in addition to an extrahippocampal lesion (dual pathology). We studied the postoperative seizure outcome of 64 patients with lesional epilepsy (median follow-up, 30 months) and considered separately the surgical results in the 51 patients with a single lesion and in the 13 who had dual pathology. In patients with a single lesion, 85% were seizure free or significantly improved (Engel's class I-II) when the lesion was totally removed compared with only 40% when there was incomplete resection (p dual pathology who had both the lesion and the atrophic hippocampus removed became seizure free. In contrast, only 2 of the 10 patients with dual pathology undergoing surgery aimed at the lesion or at the hippocampus alone became seizure free (p dual pathology, surgery should, if possible, include resection of both the lesion and the atrophic hippocampus.

  14. Asteroid hyalosis removal during phacoemulsification: an anterior approach

    Directory of Open Access Journals (Sweden)

    Mohamed Anbar

    2017-01-01

    Removal of AH by means of anterior vitrectomy during phacoemulsification through a posterior capsulorhexis is safe and effective and enables the surgeon to treat undiagnosed missed retinal lesions that were not obvious preoperatively.

  15. Modified jailed balloon technique for bifurcation lesions.

    Science.gov (United States)

    Saito, Shigeru; Shishido, Koki; Moriyama, Noriaki; Ochiai, Tomoki; Mizuno, Shingo; Yamanaka, Futoshi; Sugitatsu, Kazuya; Tobita, Kazuki; Matsumi, Junya; Tanaka, Yutaka; Murakami, Masato

    2017-12-04

    We propose a new systematic approach in bifurcation lesions, modified jailed balloon technique (M-JBT), and report the first clinical experience. Side branch occlusion brings with a serious complication and occurs in more than 7.0% of cases during bifurcation stenting. A jailed balloon (JB) is introduced into the side branch (SB), while a stent is placed in the main branch (MB) as crossing SB. The size of the JB is half of the MB stent size. While the proximal end of JB attaching to MB stent, both stent and JB are simultaneously inflated with same pressure. JB is removed and then guidewires are recrossed. Kissing balloon dilatation (KBD) and/or T and protrusion (TAP) stenting are applied as needed. Between February 2015 and February 2016, 233 patients (254 bifurcation lesions including 54 left main trunk disease) underwent percutaneous coronary intervention (PCI) using this technique. Procedure success was achieved in all cases. KBD was performed for 183 lesions and TAP stenting was employed for 31 lesions. Occlusion of SV was not observed in any of the patients. Bench test confirmed less deformity of MB stent in M-JBT compared with conventional-JBT. This is the first report for clinical experiences by using modified jailed balloon technique. This novel M-JBT is safe and effective in the preservation of SB patency during bifurcation stenting. © 2017 Wiley Periodicals, Inc.

  16. Lesion progression in post-treatment persistent endodontic lesions.

    Science.gov (United States)

    Yu, Victoria Soo Hoon; Messer, Harold Henry; Shen, Liang; Yee, Robert; Hsu, Chin-ying Stephen

    2012-10-01

    Radiographic lesions related to root-filled teeth may persist for long periods after treatment and are considered to indicate failure of initial treatment. Persistent lesions are found in a proportion of cases, but information on lesion progression is lacking. This study examined the incidence of lesion improvement, remaining unchanged, and deterioration among persistent lesions in a group of patients recruited from a university-based clinic and identified potential predictors for lesion progression. Patients of a university clinic with persistent endodontic lesions at least 4 years since treatment and with original treatment radiographs available were recruited with informed consent. Data were obtained by interview and from dental records and clinical and radiographic examinations. Univariate and multivariate statistical analyses were carried out by using SPSS (version 19). One hundred fifty-one persistent lesions were identified in 114 patients. A majority of the lesions (107, 70.9%) received treatment between 4 and 5 years prior. Eighty-six lesions (57.0%) improved, 18 (11.9%) remained unchanged, and 47 (31.1%) deteriorated since treatment. Potential predictors for lesions that did not improve included recall lesion size, pain on biting at recall examination, history of a postobturation flare-up, and a non-ideal root-filling length (P < .05). Lesions that had persisted for a longer period appeared less likely to be improving (relative risk, 1.038; 95% confidence interval, 1.000-1.077). A specific time interval alone should not be used to conclude that a lesion will not resolve without intervention. This study identified several clinical factors that are associated with deteriorating persistent lesions, which should aid in identifying lesions that require further intervention. Copyright © 2012 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  17. Endoscopically removed giant submucosal lipoma

    Directory of Open Access Journals (Sweden)

    Jovanović Ivan

    2007-01-01

    Full Text Available Background. Although uncommon, giant submucosal colon lipomas merit attention as they are often presented with dramatic clinical features such as bleeding, acute bowel obstruction, perforation and sometimes may be mistaken for malignancy. There is a great debate in the literature as to how to treat them. Case report. A patient, 67-year old, was admitted to the Clinic due to a constipation over the last several months, increasing abdominal pain mainly localized in the left lower quadrant accompanied by nausea, vomiting and abdominal distension. Physical examination was unremarkable and the results of the detailed laboratory tests and carcinoembryonic antigen remained within normal limits. Colonoscopy revealed a large 10 cm long, and 4 to 5 cm in diameter, mobile lesion in his sigmoid colon. Conventional endoscopic ultrasound revealed 5 cm hyperechoic lesion of the colonic wall. Twenty MHz mini-probe examination showed that lesion was limited to the submucosa. Since polyp appeared too large for a single transaction, it was removed piecemeal. Once the largest portion of the polyp has been resected, it was relatively easy to place the opened snare loop around portions of the residual polyp. Endoscopic resection was carried out safely without complications. Histological examination revealed the common typical histological features of lipoma elsewhere. The patient remained stable and eventually discharged home. Four weeks later he suffered no recurrent symptoms. Conclusion. Colonic lipomas can be endoscopically removed safely eliminating unnecessary surgery.

  18. Vascular lesions of the vocal fold.

    Science.gov (United States)

    Gökcan, Kürşat Mustafa; Dursun, Gürsel

    2009-04-01

    The aim of the study was to present symptoms, laryngological findings, clinical course, management modalities, and consequences of vascular lesions of vocal fold. This study examined 162 patients, the majority professional voice users, with vascular lesions regarding their presenting symptoms, laryngological findings, clinical courses and treatment results. The most common complaint was sudden hoarseness with hemorrhagic polyp. Microlaryngoscopic surgery was performed in 108 cases and the main indication of surgery was the presence of vocal fold mass or development of vocal polyp during clinical course. Cold microsurgery was utilized for removal of vocal fold masses and feeding vessels cauterized using low power, pulsed CO(2) laser. Acoustic analysis of patients revealed a significant improvement of jitter, shimmer and harmonics/noise ratio values after treatment. Depending on our clinical findings, we propose treatment algorithm where voice rest and behavioral therapy is the integral part and indications of surgery are individualized for each patient.

  19. Oxidative Glial Cell Damage Associated with White Matter Lesions in the Aging Human Brain.

    Science.gov (United States)

    Al-Mashhadi, Sufana; Simpson, Julie E; Heath, Paul R; Dickman, Mark; Forster, Gillian; Matthews, Fiona E; Brayne, Carol; Ince, Paul G; Wharton, Stephen B

    2015-09-01

    White matter lesions (WML) are common in brain aging and are associated with dementia. We aimed to investigate whether oxidative DNA damage and occur in WML and in apparently normal white matter in cases with lesions. Tissue from WML and control white matter from brains with lesions (controls lesional) and without lesions (controls non-lesional) were obtained, using post-mortem magnetic resonance imaging-guided sampling, from the Medical Research Council Cognitive Function and Ageing Study. Oxidative damage was assessed by immunohistochemistry to 8-hydroxy-2'-deoxoguanosine (8-OHdG) and Western blotting for malondialdehyde. DNA response was assessed by phosphorylated histone H2AX (γH2AX), p53, senescence markers and by quantitative Reverse transcription polymerase chain reaction (RT-PCR) panel for candidate DNA damage-associated genes. 8-OHdG was expressed in glia and endothelium, with increased expression in both WML and controls lesional compared with controls non-lesional (P glial dysfunction. Their expression in apparently normal white matter in cases with WML suggests that white matter dysfunction is not restricted to lesions. The role of this field-effect lesion pathogenesis and cognitive impairment are areas to be defined. © 2014 The Authors. Brain Pathology published by John Wiley & Sons Ltd on behalf of International Society of Neuropathology.

  20. Repair of DNA damage induced by ionizing radiation and benzo[a]pyrene in mammalian cells

    International Nuclear Information System (INIS)

    Cerutti, P.; Shinohara, K.; Remsen, J.

    1977-01-01

    The biological effects of DNA-damaging agents are codetermined by the structural characteristics of the lesions, the quality and extent of the local distortion of DNA and chromatin structure, and the mode(s) of damage processing used by a given type of cell. Persistent damage (i.e., damage that is not removed before it is reached by DNA replication) may be mostly responsible for mutagenesis and carcinogenesis. To understand the effects of environmental physical and chemical DNA-damaging agents on human health, the mechanisms of damage processing used by human cells have to be elucidated. We report our studies of the excision of gamma-ray products of the 5,6-dihydroxydihydrothymine type (t 0 /sub 2//sup γ/) in normal human fibroblasts and in fibroblasts from patients with the hereditary diseases Fanconi's anemia (FA) and ataxia telangiectasia (AT). Both diseases are characterized by chromosomal instability and increased susceptibility for the development of cancer. Formation and repair of DNA-benzo[a]pyrene adducts were studied in baby hamster kidney cells, secondary mouse embryo cells, and human lymphoma. The relative persistence of DNA-B[a]P may explain the high mutagenicity of the 7,8-dihydroxy-9,10-epoxy-tetrahydrobenzo[a]pyrene metabolites in rodent cells that has been observed by several investigators

  1. Introduction to DNA methods

    International Nuclear Information System (INIS)

    Delincee, H.

    1991-01-01

    The purpose of this session is to discuss the various possibilities for detecting modifications in DNA after irradiation and whether these changes can be utilized as an indicator for the irradiation treatment of foods. The requirement to be fulfilled is that the method be able to distinguish irradiated food without the presence of a control sample, thus the measured response after irradiation must be large enough to supersede background levels from other treatments. Much work has been performed on the effects of radiation on DNA, particularly due to its importance in radiation biology. The main lesions of DNA as a result of irradiation are base damage, damage of the sugar moiety, single strand and double strand breaks. Crosslinking between bases also occurs, e.g. production of thymine dimers, or between DNA and protein. A valuable review on how to utilize these DNA changes for detection purposes has already appeared. Tables 1, 2 and 3 list the proposed methods of detecting changes in irradiated DNA, some identified products as examples for a possible irradiation indicator, in the case of immunoassay the substance used as antigen, and some selected literature references. In this short review, it is not intended to provide a complete literature survey

  2. Acute periodontal lesions.

    Science.gov (United States)

    Herrera, David; Alonso, Bettina; de Arriba, Lorenzo; Santa Cruz, Isabel; Serrano, Cristina; Sanz, Mariano

    2014-06-01

    This review provides updates on acute conditions affecting the periodontal tissues, including abscesses in the periodontium, necrotizing periodontal diseases and other acute conditions that cause gingival lesions with acute presentation, such as infectious processes not associated with oral bacterial biofilms, mucocutaneous disorders and traumatic and allergic lesions. A periodontal abscess is clinically important because it is a relatively frequent dental emergency, it can compromise the periodontal prognosis of the affected tooth and bacteria within the abscess can spread and cause infections in other body sites. Different types of abscesses have been identified, mainly classified by their etiology, and there are clear differences between those affecting a pre-existing periodontal pocket and those affecting healthy sites. Therapy for this acute condition consists of drainage and tissue debridement, while an evaluation of the need for systemic antimicrobial therapy will be made for each case, based on local and systemic factors. The definitive treatment of the pre-existing condition should be accomplished after the acute phase is controlled. Necrotizing periodontal diseases present three typical clinical features: papilla necrosis, gingival bleeding and pain. Although the prevalence of these diseases is not high, their importance is clear because they represent the most severe conditions associated with the dental biofilm, with very rapid tissue destruction. In addition to bacteria, the etiology of necrotizing periodontal disease includes numerous factors that alter the host response and predispose to these diseases, namely HIV infection, malnutrition, stress or tobacco smoking. The treatment consists of superficial debridement, careful mechanical oral hygiene, rinsing with chlorhexidine and daily re-evaluation. Systemic antimicrobials may be used adjunctively in severe cases or in nonresponding conditions, being the first option metronidazole. Once the acute

  3. Localization of lesions in aphasia

    International Nuclear Information System (INIS)

    Hojo, Kei; Watanabe, Shunzo; Tasaki, Hiroichi; Sato, Tokijiro; Metoki, Hirobumi.

    1984-01-01

    Using a microcomputer, the locus and extent of the lesions, as demonstrated by computed tomography for 127 cases with various types of aphasia were superimposed onto standardized marices. The relationship between the foci of the lesions and the types of aphasia was investigated. Broca aphasics (n=39) : Since the accumulated site of the lesions highly involved the deep structures of the lower part of the precentral gyrus as well as the insula and lenticular nucleus, only 60% of the Broca aphasics had lesions on these areas. This finding has proved to have little localizing value. Wernicke aphasics (n=23) : The size of the lesion was significantly smaller than Broca's aphasia. At least 70% of the patients had the superior temporal lesions involving Wernicke's area and subcortical lesions of the superior and middle temporal gyri. Amnestic aphasics (n=18) : The size of the lesion was smaller than any other types. While there was some concentration of the lesions (maximum 40%) in the area of the subcortical region of the anterior temporal gyrus adjacent to Wernicke's area and the lenticular nucleus, the lesions were distributed throughout the left hemisphere. Amnestic aphasia was thought to be the least localizable. Conduction aphasics (n=11) : The lesions were relatively small in size. Many patients had posterior speech area lesions involving at least partially Wernicke's area. In particular, more than 80% of the conduction aphasics had lesions of the supramarginal gyrus and it's adjacent deep structures. Global aphasics (n=36) : In general, the size of the lesion was very large and 70% of the global aphasics had extensive lesions involving both Broca's and Wernicke's areas. However, there were observations showing that the lesions can be small and confined. (J.P.N.)

  4. Fanconi anemia (cross)linked to DNA repair.

    Science.gov (United States)

    Niedernhofer, Laura J; Lalai, Astrid S; Hoeijmakers, Jan H J

    2005-12-29

    Fanconi anemia is characterized by hypersensitivity to DNA interstrand crosslinks (ICLs) and susceptibility to tumor formation. Despite the identification of numerous Fanconi anemia (FANC) genes, the mechanism by which proteins encoded by these genes protect a cell from DNA interstrand crosslinks remains unclear. The recent discovery of two DNA helicases that, when defective, cause Fanconi anemia tips the balance in favor of the direct involvement of the FANC proteins in DNA repair and the bypass of DNA lesions.

  5. A disappearing neonatal skin lesion.

    LENUS (Irish Health Repository)

    Hawkes, Colin Patrick

    2012-01-31

    A preterm baby girl was noted at birth to have a firm, raised, non-tender skin lesion located over her right hip. She developed three similar smaller lesions on her ear, buttock and right knee. All lesions had resolved by 2 months of age.

  6. Transcriptome Analysis Reveals Markers of Aberrantly Activated Innate Immunity in Vitiligo Lesional and Non-Lesional Skin

    Science.gov (United States)

    Huang, Yuanshen; Wang, Yang; Yu, Jie; Gao, Min; Levings, Megan; Wei, Shencai; Zhang, Shengquan; Xu, Aie; Su, Mingwan; Dutz, Jan; Zhang, Xuejun; Zhou, Youwen

    2012-01-01

    Background Vitiligo is characterized by the death of melanocytes in the skin. This is associated with the presence of T cell infiltrates in the lesional borders. However, at present, there is no detailed and systematic characterization on whether additional cellular or molecular changes are present inside vitiligo lesions. Further, it is unknown if the normal appearing non-lesional skin of vitiligo patients is in fact normal. The purpose of this study is to systematically characterize the molecular and cellular characteristics of the lesional and non-lesional skin of vitiligo patients. Methods and Materials Paired lesional and non-lesional skin biopsies from twenty-three vitiligo patients and normal skin biopsies from sixteen healthy volunteers were obtained with informed consent. The following aspects were analyzed: (1) transcriptome changes present in vitiligo skin using DNA microarrays and qRT-PCR; (2) abnormal cellular infiltrates in vitiligo skin explant cultures using flow cytometry; and (3) distribution of the abnormal cellular infiltrates in vitiligo skin using immunofluorescence microscopy. Results Compared with normal skin, vitiligo lesional skin contained 17 genes (mostly melanocyte-specific genes) whose expression was decreased or absent. In contrast, the relative expression of 13 genes was up-regulated. The up-regulated genes point to aberrant activity of the innate immune system, especially natural killer cells in vitiligo. Strikingly, the markers of heightened innate immune responses were also found to be up-regulated in the non-lesional skin of vitiligo patients. Conclusions and Clinical Implications As the first systematic transcriptome characterization of the skin in vitiligo patients, this study revealed previously unknown molecular markers that strongly suggest aberrant innate immune activation in the microenvironment of vitiligo skin. Since these changes involve both lesional and non-lesional skin, our results suggest that therapies targeting

  7. My journey to DNA repair.

    Science.gov (United States)

    Lindahl, Tomas

    2013-02-01

    I completed my medical studies at the Karolinska Institute in Stockholm but have always been devoted to basic research. My longstanding interest is to understand fundamental DNA repair mechanisms in the fields of cancer therapy, inherited human genetic disorders and ancient DNA. I initially measured DNA decay, including rates of base loss and cytosine deamination. I have discovered several important DNA repair proteins and determined their mechanisms of action. The discovery of uracil-DNA glycosylase defined a new category of repair enzymes with each specialized for different types of DNA damage. The base excision repair pathway was first reconstituted with human proteins in my group. Cell-free analysis for mammalian nucleotide excision repair of DNA was also developed in my laboratory. I found multiple distinct DNA ligases in mammalian cells, and led the first genetic and biochemical work on DNA ligases I, III and IV. I discovered the mammalian exonucleases DNase III (TREX1) and IV (FEN1). Interestingly, expression of TREX1 was altered in some human autoimmune diseases. I also showed that the mutagenic DNA adduct O(6)-methylguanine (O(6)mG) is repaired without removing the guanine from DNA, identifying a surprising mechanism by which the methyl group is transferred to a residue in the repair protein itself. A further novel process of DNA repair discovered by my research group is the action of AlkB as an iron-dependent enzyme carrying out oxidative demethylation. Copyright © 2013. Production and hosting by Elsevier Ltd.

  8. The unstructured linker arms of Mlh1-Pms1 are important for interactions with DNA during mismatch repair

    Science.gov (United States)

    Plys, Aaron J.; Rogacheva, Maria V.; Greene, Eric C.; Alani, Eric

    2012-01-01

    DNA mismatch repair (MMR) models have proposed that MSH proteins identify DNA polymerase errors while interacting with the DNA replication fork. MLH proteins (primarily Mlh1-Pms1 in baker’s yeast) then survey the genome for lesion-bound MSH proteins. The resulting MSH-MLH complex formed at a DNA lesion initiates downstream steps in repair. MLH proteins act as dimers and contain long (20 – 30 nanometers) unstructured arms that connect two terminal globular domains. These arms can vary between 100 to 300 amino acids in length, are highly divergent between organisms, and are resistant to amino acid substitutions. To test the roles of the linker arms in MMR, we engineered a protease cleavage site into the Mlh1 linker arm domain of baker’s yeast Mlh1-Pms1. Cleavage of the Mlh1 linker arm in vitro resulted in a defect in Mlh1-Pms1 DNA binding activity, and in vivo proteolytic cleavage resulted in a complete defect in MMR. We then generated a series of truncation mutants bearing Mlh1 and Pms1 linker arms of varying lengths. This work revealed that MMR is greatly compromised when portions of the Mlh1 linker are removed, whereas repair is less sensitive to truncation of the Pms1 linker arm. Purified complexes containing truncations in Mlh1 and Pms1 linker arms were analyzed and found to have differential defects in DNA binding that also correlated with the ability to form a ternary complex with Msh2-Msh6 and mismatch DNA. These observations are consistent with the unstructured linker domains of MLH proteins providing distinct interactions with DNA during MMR. PMID:22659005

  9. Lesiones deportivas Sports injuries

    Directory of Open Access Journals (Sweden)

    Isabel Cristina Gallego Ching

    2007-04-01

    Full Text Available El estrés generado por la práctica deportiva ha originado una mayor probabilidad de que los atletas presenten lesiones agudas y crónicas. En el ámbito mundial existen diferentes investigaciones acerca de la incidencia de lesiones deportivas. La comparación de sus resultados es difícil por las diferencias en las características de la población y en la forma de reportar los datos, que varía ampliamente entre los estudios (proporciones o tasas de incidencia o tasas por cada 100 ó 1.000 participantes o tasas por horas de juego o por número de partidos jugados. Las tasas varían entre 1,7 y 53 lesiones por 1.000 horas de práctica deportiva, entre 0,8 y 90,9 por 1.000 horas de entrenamiento, entre 3,1 y 54,8 por 1.000 horas de competición y de 6,1 a 10,9 por 100 juegos. La gran variación entre las tasas de incidencia se explica por las diferencias existentes entre los deportes, los países, el nivel competitivo, las edades y la metodología empleada en los estudios. Se ha definido la lesión deportiva como la que ocurre cuando los atletas están expuestos a la práctica del deporte y se produce alteración o daño de un tejido, afectando el funcionamiento de la estructura. Los deportes de contacto generan mayor riesgo de presentar lesiones; se destacan al respecto los siguientes: fútbol, rugby, baloncesto, balonmano, artes marciales y jockey. Las lesiones ocurren con mayor probabilidad en las competencias que en el entrenamiento. Stress generated by sports practice has increased the probability that athletes suffer from acute and chronic injuries. Worldwide, there have been many different investigations concerning the incidence of sport injuries. The different ways in which results have been presented makes it difficult to compare among them. Rates of sports injuries vary between 1.7 and 53 per 1.000 hours of sports practice; 0.8 and 90.9 per 1.000 hours of training; 3.1 and 54.8 per 1.000 hours of competition, and 6.1 and 10.9 per 100

  10. Analysis of pulmonary coin lesions

    International Nuclear Information System (INIS)

    Kim, O; Kim, K. H.; Oh, K. K.; Park, C. Y.

    1979-01-01

    For A long time the solitary pulmonary nodule has remained a difficult problem to solve and has attracted a great deal of attension in recent years. Circumscribed coin lesions of the lung were generally peripheral in location with respect to the pulmonary hilus. Because of this, important clinical problem in management and diagnosis arise. Such a lesion is discovered through roentgenologic examination. So the roentgenologists is the first be in a position to offer advise. This presentation is an attempt to correlate a useful diagnosis with roentgenologic findings of pulmonary coin lesion which enables us to get differential diagnosis of benign and malignant lesion. Histologically proven 120 cases of the pulmonary coin lesion during the period of 8 years were reviewed through plain film, tomogram, bronchoscopy, variable laboratory findings, and clinical history. The results are as follows: 1. Male to female sex ratio was 3 : 1. In age distribution, most of the malignant pulmonary coin lesion appeared in 6th decade (39%) and 5th decade (27%). In benign lesion, the most cases were in 3 rd decade. 2. Pathological cell type are as follows: Primary bronchogenic cancer 43.3%, tuberculoma 25.8%, inflammatory lesion 17.5%, benign tumor 10%, and bronchial adenoma, harmartoma, A.V. malformation, mesothelioma, are 1 case respectively. As a result benign and malignant lesion showed equal distribution (49.1% : 50.3%). 3. In symptom analysis ; cough is the most common (43.5%) symptom in malignant lesion, next follows hemoptysis (20.9%) and chest pain (14.5%). In benign lesion, most of the patient (32.7%) did not complain any symptom. 4. In malignant lesion, the most common nodular size was 4 cm (32.3%), and in benign lesion 2 cm sized coin was most common (39.3%). 5. In general, margin of nodule was very sharp and well demarcated in benign lesion (83.3%), and in malignant lesion that was less demarcated and poorly defined. 6. Most case of calcification (82.7%) was seen in benign

  11. Surgical treatment of gallbladder polypoid lesions

    Directory of Open Access Journals (Sweden)

    Pejić Miljko A.

    2003-01-01

    with biliary colic should be managed conservatively. Cholecystectomy is also indicated in patients with large gallbladder polyps sized over 10 mm irrespective of symptomatology. In patients with gallbladder polypoid lesions smaller than 10 mm, cholecystectomy is indicated only if complicating factors are present, e.g., age over 50 years and coexistence of gallstones. If the gallbladder polyp is smaller than 10 mm and complicating factors are absent, the "watch-and-wait" strategy seems to be recommendable. CONCLUSION Although gallbladder polyps are rare, they represent a significant health problem because they may be a precursor to gallbladder cancer. On the basis of the available data, and the results that we have gained in our study we suggest that gallbladder should be extirpated in cases when: 1. symptomatic lesions are present regardless of size; 2. polyps larger than 10 mm are present because they represent a risk for gallbladder cancer; 3. polyps are showing rapid increase in size. Polyps less than 10 mm that are incidentally identified and not removed should be assessed by ultrasonography at least every six months. This is especially critical for sessile polyps, in which the possibility of a small cancerous polyp is greater than in pedunculated polyps. Also, asymptomatic lesions less than 10 mm in diameter should be removed if patient is older than 50 years or if he has concomitant gallbladder calculosis.

  12. Study of genital lesions

    Directory of Open Access Journals (Sweden)

    Anand Kumar B

    2003-03-01

    Full Text Available A total of one hundred patients (75 males and 25 females age ranged from 17-65 years with genital lesions attending the STD clinic of Bowring and LC Hospitals Bangalore constituted the study group. Based on clinical features, the study groups were classified as syphilis (39, chancroid (30, herpes genitolis (13, condylomato lato (9, LGV (7t condylomata acuminata (5, genital scabies (3, granuloma inguinole (2 and genital candidiasis (1. In 68% microbiological findings confirmed the clinical diagnosis. Of the 100 cases 13% and 2% were positive for HIV antibodies and HbsAg respectively.

  13. Structural basis for the inhibition of human alkyladenine DNA glycosylase (AAG) by 3,N4-ethenocytosine-containing DNA.

    Science.gov (United States)

    Lingaraju, Gondichatnahalli M; Davis, C Ainsley; Setser, Jeremy W; Samson, Leona D; Drennan, Catherine L

    2011-04-15

    Reactive oxygen and nitrogen species, generated by neutrophils and macrophages in chronically inflamed tissues, readily damage DNA, producing a variety of potentially genotoxic etheno base lesions; such inflammation-related DNA damage is now known to contribute to carcinogenesis. Although the human alkyladenine DNA glycosylase (AAG) can specifically bind DNA containing either 1,N(6)-ethenoadenine (εA) lesions or 3,N(4)-ethenocytosine (εC) lesions, it can only excise εA lesions. AAG binds very tightly to DNA containing εC lesions, forming an abortive protein-DNA complex; such binding not only shields εC from repair by other enzymes but also inhibits AAG from acting on other DNA lesions. To understand the structural basis for inhibition, we have characterized the binding of AAG to DNA containing εC lesions and have solved a crystal structure of AAG bound to a DNA duplex containing the εC lesion. This study provides the first structure of a DNA glycosylase in complex with an inhibitory base lesion that is induced endogenously and that is also induced upon exposure to environmental agents such as vinyl chloride. We identify the primary cause of inhibition as a failure to activate the nucleotide base as an efficient leaving group and demonstrate that the higher binding affinity of AAG for εC versus εA is achieved through formation of an additional hydrogen bond between Asn-169 in the active site pocket and the O(2) of εC. This structure provides the basis for the design of AAG inhibitors currently being sought as an adjuvant for cancer chemotherapy.

  14. Vascular lesions following radiation

    International Nuclear Information System (INIS)

    Fajardo, L.F.; Berthrong, M.

    1988-01-01

    The special radiation sensitivity of the vascular system is mainly linked to that of endothelial cells, which are perhaps the most radiation-vulnerable elements of mesenchymal tissues. Within the vascular tree, radiation injures most often capillaries, sinusoids, and small arteries, in that order. Lesions of veins are observed less often, but in certain tissues the veins are regularly damaged (e.g., intestine) or are the most affected structures (i.e., liver). Large arteries do suffer the least; however, when significant damage does occur in an elastic artery (e.g., thrombosis or rupture), it tends to be clinically significant and even fatal. Although not always demonstrable in human tissues, radiation vasculopathy generally is dose and time dependent. Like other radiation-induced lesions, the morphology in the vessels is not specific, but it is characteristic enough to be often recognizable. Vascular injury, especially by therapeutic radiation is not just a morphologic marker. It is a mediator of tissue damage; perhaps the most consistent pathogenetic mechanism in delayed radiation injury

  15. The Fanconi anemia pathway promotes replication-dependent DNA interstrand cross-link repair.

    Science.gov (United States)

    Knipscheer, Puck; Räschle, Markus; Smogorzewska, Agata; Enoiu, Milica; Ho, The Vinh; Schärer, Orlando D; Elledge, Stephen J; Walter, Johannes C

    2009-12-18

    Fanconi anemia is a human cancer predisposition syndrome caused by mutations in 13 Fanc genes. The disorder is characterized by genomic instability and cellular hypersensitivity to chemicals that generate DNA interstrand cross-links (ICLs). A central event in the activation of the Fanconi anemia pathway is the mono-ubiquitylation of the FANCI-FANCD2 complex, but how this complex confers ICL resistance remains enigmatic. Using a cell-free system, we showed that FANCI-FANCD2 is required for replication-coupled ICL repair in S phase. Removal of FANCD2 from extracts inhibits both nucleolytic incisions near the ICL and translesion DNA synthesis past the lesion. Reversal of these defects requires ubiquitylated FANCI-FANCD2. Our results show that multiple steps of the essential S-phase ICL repair mechanism fail when the Fanconi anemia pathway is compromised.

  16. Prevalence of periapical lesions in endodontic treatment teeth

    Directory of Open Access Journals (Sweden)

    Juliana Machado Barroso

    2013-01-01

    Full Text Available The aim of this study was to determine the prevalence of of persistent periapical lesions after conventional endodontic therapy. The persistent periapical lesions were removed paraendodontic surgery, followed by apicoectomy. The root ends were retroprepared with ultrasound and retrofilling with MTA. The specimens were stored in formaldehyde 10%, making a total of 107 samples. The lesions were referred to the Department of Pathology, FOB-USP for microscopic analysis using the technique of serial sections. The present results showed periapical cyst (48, granuloma (43, Crohn's abscess (2, apical fibrosis (3 and others (11. . Among the lesions analyzed in this study it can be observed a higher incidence of apical periodontal cyst, followed by apical granuloma and other pathologies.

  17. PREVALENCE OF PERIAPICAL LESIONS IN ENDODONTIC TREATMENT TEETH

    Directory of Open Access Journals (Sweden)

    Francisco Carlos Ribeiro

    2013-04-01

    Full Text Available The aim of this study was to determine the prevalence of of persistent periapical lesions after conventional endodontic therapy. The persistent periapical lesions were removed paraendodontic surgery, followed by apicoectomy. The root ends were retroprepared with ultrasound and retrofilling with MTA. The specimens were stored in formaldehyde 10%, making a total of 107 samples. The lesions were referred to the Department of Pathology, FOB-USP for microscopic analysis using the technique of serial sections. The present results showed periapical cyst (48, granuloma (43, Crohn's abscess (2, apical fibrosis (3 and others (11. . Among the lesions analyzed in this study it can be observed a higher incidence of apical periodontal cyst, followed by apical granuloma and other pathologies.

  18. Progression of periapical cystic lesion after incomplete endodontic treatment

    Directory of Open Access Journals (Sweden)

    Jong-Ki Huh

    2016-05-01

    Full Text Available We report a case of large radicular cyst progression related to endodontic origin to emphasize proper intervention and follow-up for endodontic pathosis. A 25 yr old man presented with an endodontically treated molar with radiolucency. He denied any intervention because of a lack of discomfort. Five years later, the patient returned. The previous periapical lesion had drastically enlarged and involved two adjacent teeth. Cystic lesion removal and apicoectomy were performed on the tooth. Histopathological analysis revealed that the lesion was an inflammatory radicular cyst. The patient did not report any discomfort except for moderate swelling 3 days after the surgical procedure. Although the patient had been asymptomatic, close follow-ups are critical to determine if any periapical lesions persist after root canal treatment.

  19. Non-homologous end joining pathway is the major route of protection against 4β-hydroxywithanolide E-induced DNA damage in MCF-7 cells.

    Science.gov (United States)

    You, B-J; Wu, Y-C; Lee, C-L; Lee, H-Z

    2014-03-01

    4β-Hydroxywithanolide E is a bioactive withanolide extracted from Physalis peruviana. 4β-Hydroxywithanolide E caused reactive oxygen species production and cell apoptosis in human breast cancer MCF-7 cells. We further found that 4β-hydroxywithanolide E induced DNA damage and regulated the DNA damage signaling in MCF-7 cells. The DNA damage sensors and repair proteins act promptly to remove DNA lesions by 4β-hydroxywithanolide E. The ataxia-telangiectasia mutated protein (ATM)-dependent DNA damage signaling pathway is involved in 4β-hydroxywithanolide E-induced apoptosis of MCF-7 cells. Non-homologous end joining pathway, but not homologous recombination, is the major route of protection of MCF-7 cells against 4β-hydroxywithanolide E-induced DNA damage. 4β-Hydroxywithanolide E had no significant impact on the base excision repair pathway. In this study, we examined the 4β-hydroxywithanolide E-induced DNA damage as a research tool in project investigating the DNA repair signaling in breast cancer cells. We also suggest that 4β-hydroxywithanolide E assert its anti-tumor activity in carcinogenic progression and develop into a dietary chemopreventive agent. Copyright © 2014 Elsevier Ltd. All rights reserved.

  20. Repairability during G1 of the inductor leisure of exchanges in the sister chromatid induced by alkylating agents in DNA substituted and no substituted with BUDR, in cells of the salivary gland of mouse In vivo; Reparabilidad durante G1 de las lesiones inductoras de intercambios en las cromatidas hermanas inducidos por agentes alquilantes en ADN sustituido y no sustituido con BrdU, en celulas de la glandula salival de raton In vivo

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez B, F

    2004-07-01

    In this work you determines the repair of the lesions inductoras of Sister chromatid exchange (ICHs) generated in the cells of the salivary gland of mouse, for the treatment with the N-Methyl-N-Nitrosourea (MNU), the N-Ethyl-N-Nitrosourea (ENU), the Methyl methanesulfonate (MMS) and the Ethyl methanesulfonate (EMS) in early and slow G1 of the first one and the second cellular division, that is to say before and after the cells incorporate 5-bromine-2 -Desoxyuridine (BrdU) in the DNA. Groups witness non treaties were included with mutagen. The cells of the salivary gland repaired the generated lesions partially by the MNU, the MMS and the EMS in the 1st division, and only the lesions induced by the ENU and MMS were repaired partially in the 2nd division. The ENU generates injure that they were not repaired in the 1st division and those taken place by the EMS were little repaired in the 2nd division. The methylating agents generated but ICHs that the ethylating. One observes that the BrdU makes to the molecule of the DNA but susceptible to the damage generated by the alkylating agents that induce the formation of the ICHs. This susceptibility was incremented around 150% for the treatment with the MNU, the ENU and the MMS, on the other hand for the EMS it was 3 times minor. It is proposed that the one electronegative atom of this analog of the timine would to work as a nucleophyllic center with which the electrophyllic compounds react. (Author)

  1. Diode Laser Excision of Oral Benign Lesions.

    Science.gov (United States)

    Mathur, Ena; Sareen, Mohit; Dhaka, Payal; Baghla, Pallavi

    2015-01-01

    Lasers have made tremendous progress in the field of dentistry and have turned out to be crucial in oral surgery as collateral approach for soft tissue surgery. This rapid progress can be attributed to the fact that lasers allow efficient execution of soft tissue procedures with excellent hemostasis and field visibility. When matched to scalpel, electrocautery or high frequency devices, lasers offer maximum postoperative patient comfort. Four patients agreed to undergo surgical removal of benign lesions of the oral cavity. 810 nm diode lasers were used in continuous wave mode for excisional biopsy. The specimens were sent for histopathological examination and patients were assessed on intraoperative and postoperative complications. Diode laser surgery was rapid, bloodless and well accepted by patients and led to complete resolution of the lesions. The excised specimen proved adequate for histopathological examination. Hemostasis was achieved immediately after the procedure with minimal postoperative problems, discomfort and scarring. We conclude that diode lasers are rapidly becoming the standard of care in contemporary dental practice and can be employed in procedures requiring excisional biopsy of oral soft tissue lesions with minimal problems in histopathological diagnosis.

  2. White matter lesion progression

    DEFF Research Database (Denmark)

    Hofer, Edith; Cavalieri, Margherita; Bis, Joshua C

    2015-01-01

    10 cohorts. To assess the relative contribution of genetic factors to progression of WML, we compared in 7 cohorts risk models including demographics, vascular risk factors plus single-nucleotide polymorphisms that have been shown to be associated cross-sectionally with WML in the current......BACKGROUND AND PURPOSE: White matter lesion (WML) progression on magnetic resonance imaging is related to cognitive decline and stroke, but its determinants besides baseline WML burden are largely unknown. Here, we estimated heritability of WML progression, and sought common genetic variants...... associated with WML progression in elderly participants from the Cohorts for Heart and Aging Research in Genomic Epidemiology (CHARGE) consortium. METHODS: Heritability of WML progression was calculated in the Framingham Heart Study. The genome-wide association study included 7773 elderly participants from...

  3. Neurosurgical Management of Nonmissile Penetrating Cranial Lesions.

    Science.gov (United States)

    de Holanda, Luciano Ferreira; Pereira, Benedito Jamilson A; Holanda, Rafael Rodrigues; Neto, José Targino; de Holanda, Carlos Vanderlei M; Giudicissi Filho, Miguel; de Oliveira, Nathalia Ribeiro Cunha; de Oliveira, Jean G

    2016-06-01

    The objective of this study is to present a case series of nonmissile penetrating (NMP) injuries and to establish a workflow for an uncommon mechanism of traumatic head injury through the analysis of each case, classification of the type of lesion, management, and outcome score at follow-up. From January 1991 to December 2008, 36,000 patients presenting with traumatic brain injury (TBI) were admitted in the Department of Neurosurgery, Hospital Antônio Targino, Campina Grande-PB, Brazil. From these patients, 11 presenting with lesions caused by NMP objects were selected. Among the 11 patients, 9 were men and 2 were women. Their ages ranged from 7 to 74 years old (mean age ± SD, 29.1 ± 22.99 years). All patients underwent neuroradiologic evaluation. The entry point was classified as natural (orbit) or artificial (skull transfixation), and we also divided the patients presenting with secondary parenchymal or vascular damage from those presenting with only lesions caused by the primary penetration into the cranium and meninges. All patients were neurosurgically treated with removal of the foreign body through craniotomy, except the patient whose object (pen) was removed without craniotomy with local anesthesia. Glasgow Coma Scale (GCS) score on admission was a statistically significant factor on prognosis, and any patient who presented with a GCS score of 15 evolved satisfactorily, and there were no deaths in this group of patients (P = 0.04). TBIs caused by NMP objects are unusual and caused by aggression, self-inflicted harm (in the case of psychiatric patients), and accident. The foreign body may enter into the skull through a natural hole (orbit, nose, mouth, or ear) or crosses the skull, causing a fracture and creating an artificial hole. Preoperative neuroradiologic assessment is paramount for the correct neurosurgical approach. The main prognostic factor for these patients is the GCS score at admission. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Tattoo removal with ingenol mebutate

    Directory of Open Access Journals (Sweden)

    Cozzi SJ

    2017-05-01

    Full Text Available Sarah-Jane Cozzi,1 Thuy T Le,1 Steven M Ogbourne,2 Cini James,1 Andreas Suhrbier1 1Inflammation Biology Laboratory, QIMR Berghofer Medical Research Institute, Brisbane, 2Genecology Research Center, Faculty of Science, Health, Engineering and Education, University of the Sunshine Coast, Maroochydore DC, QLD, Australia Abstract: An increasing number of people are getting tattoos; however, many regret the decision and seek their removal. Lasers are currently the most commonly used method for tattoo removal; however, treatment can be lengthy, costly, and sometimes ineffective, especially for certain colors. Ingenol mebutate is a licensed topical treatment for actinic keratoses. Here, we demonstrate that two applications of 0.1% ingenol mebutate can efficiently and consistently remove 2-week-old tattoos from SKH/hr hairless mice. Treatment was associated with relocation of tattoo microspheres from the dermis into the posttreatment eschar. The skin lesion resolved about 20 days after treatment initiation, with some cicatrix formation evident. The implications for using ingenol mebutate for tattoo removal in humans are discussed. Keywords: tattoo, ingenol mebutate, mouse 

  5. Modeling DNA

    Science.gov (United States)

    Robertson, Carol

    2016-01-01

    Deoxyribonucleic acid (DNA) is life's most amazing molecule. It carries the genetic instructions that almost every organism needs to develop and reproduce. In the human genome alone, there are some three billion DNA base pairs. The most difficult part of teaching DNA structure, however, may be getting students to visualize something as small as a…

  6. A simple and cost-effective method of DNA extraction from small formalin-fixed paraffin-embedded tissue for molecular oncologic testing.

    Science.gov (United States)

    Snow, Anthony N; Stence, Aaron A; Pruessner, Jonathan A; Bossler, Aaron D; Ma, Deqin

    2014-01-01

    Extraction of DNA from formalin-fixed, paraffin-embedded (FFPE) tissue is a critical step in molecular oncologic testing. As molecular oncology testing becomes more important for prognostic and therapeutic decision making and tissue specimens become smaller due to earlier detection of suspicious lesions and the use of fine needle aspiration methods for tissue collection, it becomes more challenging for the typical molecular pathology laboratory to obtain reliable test results. We developed a DNA extraction method to obtain sufficient quantity and high quality genomic DNA from limited FFPE tissue for molecular oncology testing using a combination of H&E stained slides, a matrix capture method and the Qiagen DNA column. THREE DNA EXTRACTION METHODS WERE COMPARED: our standard procedure of manually scraping tissue from unstained slides followed by DNA extraction using the QIAamp FFPE column (Qiagen, Valencia, CA), a glue capture method (Pinpoint Solution, Zymo Research Corp, Inc) on H&E stained slides followed by DNA extraction using either the QIAamp column or the column included with the Pinpoint kit (Zymo Research). The DNA extraction protocol was optimized. Statistical analysis was performed using the paired two-sample student's t-test. The combination of the matrix capture method with the QIAamp column gave an equivalent amount of DNA as our standard extraction method using the unstained slides and a 4.6-fold higher DNA yield than using the Zymo column included in the Pinpoint Slide Solution kit. Several molecular tests were performed and DNA purified using the new method gave the same results as for the previous methods. Using H&E stained slides allows visual confirmation of tumor cells during microdissection. The Pinpoint solution made removal of specific tissue from the slides easier and reduced the risk of contamination and tissue loss. This DNA extraction method is simple, cost-effective, and blends with our current workflow requiring no additional equipment.

  7. MALIGNANCY IN LARGE COLORECTAL LESIONS

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    Carlos Eduardo Oliveira dos SANTOS

    2014-09-01

    Full Text Available Context The size of colorectal lesions, besides a risk factor for malignancy, is a predictor for deeper invasion Objectives To evaluate the malignancy of colorectal lesions ≥20 mm. Methods Between 2007 and 2011, 76 neoplasms ≥20 mm in 70 patients were analyzed Results The mean age of the patients was 67.4 years, and 41 were women. Mean lesion size was 24.7 mm ± 6.2 mm (range: 20 to 50 mm. Half of the neoplasms were polypoid and the other half were non-polypoid. Forty-two (55.3% lesions were located in the left colon, and 34 in the right colon. There was a high prevalence of III L (39.5% and IV (53.9% pit patterns. There were 72 adenomas and 4 adenocarcinomas. Malignancy was observed in 5.3% of the lesions. Thirty-three lesions presented advanced histology (adenomas with high-grade dysplasia or early adenocarcinoma, with no difference in morphology and site. Only one lesion (1.3% invaded the submucosa. Lesions larger than 30 mm had advanced histology (P = 0.001. The primary treatment was endoscopic resection, and invasive carcinoma was referred to surgery. Recurrence rate was 10.6%. Conclusions Large colorectal neoplasms showed a low rate of malignancy. Endoscopic treatment is an effective therapy for these lesions.

  8. Hepatocytes, rather than leukocytes reverse DNA damage in vivo induced by whole body y-irradiation of mice, as shown by the alkaline comet assay

    Directory of Open Access Journals (Sweden)

    JUANA PINCHEIRA

    2008-01-01

    Full Text Available DNA damage repair was assessed in quiescent (G0 leukocytes and in hepatocytes of mice, after 1 and 2 hours recovery from a single whole body y-irradiation with 0.5, 1 or 2 Gy. Evaluation of single-strand breaks (SSB and alkali-labile sites together were carried out by a single-cell electrophoresis at pH>13.0 (alkaline comet assay. In non-irradiated (control mice, the constitutive, endogenous DNA damage (basal was around 1.5 times higher in leukocytes than in hepatocytes. Irradiation immediately increased SSB frequency in both cell types, in a dose-dependent manner. Two sequential phases took place during the in vivo repair of the radio-induced DNA lesions. The earliest one, present in both hepatocytes and leukocytes, further increased the SSB frequency, making evident the processing of some primary lesions in DNA bases into the SSB repair intermediates. In a second phase, SSB frequency decreased because of their removal. In hepatocytes, such a frequency regressed to the constitutive basal level after 2 hours recovery from either 0.5 orí Gy. On the other hand, the SSB repair phase was specifically abrogated in leukocytes, at the doses and recovery times analyzed. Thus, the efficiency of in vivo repair of radio-induced DNA damage in dormant cells (lymphocytes is quite different from that in hepatocytes whose low proliferation activity accounts only for cell renewal.

  9. Repair of abasic sites in DNA

    Energy Technology Data Exchange (ETDEWEB)

    Dianov, Grigory L.; Sleeth, Kate M.; Dianova, Irina I.; Allinson, Sarah L

    2003-10-29

    Repair of both normal and reduced AP sites is activated by AP endonuclease, which recognizes and cleaves a phosphodiester bond 5' to the AP site. For a short period of time an incised AP site is occupied by poly(ADP-ribose) polymerase and then DNA polymerase {beta} adds one nucleotide into the repair gap and simultaneously removes the 5'-sugar phosphate. Finally, the DNA ligase III/XRCC1 complex accomplishes repair by sealing disrupted DNA ends. However, long-patch BER pathway, which is involved in the removal of reduced abasic sites, requires further DNA synthesis resulting in strand displacement and the generation of a damage-containing flap that is later removed by the flap endonuclease. Strand-displacement DNA synthesis is accomplished by DNA polymerase {delta}/{epsilon} and DNA ligase I restores DNA integrity. DNA synthesis by DNA polymerase {delta}/{epsilon} is dependent on proliferating cell nuclear antigen, which also stimulates the DNA ligase I and flap endonuclease. These repair events are supported by multiple protein-protein interactions.

  10. Chromatin associated mechanisms in base excision repair - nucleosome remodeling and DNA transcription, two key players.

    Science.gov (United States)

    Menoni, Hervé; Di Mascio, Paolo; Cadet, Jean; Dimitrov, Stefan; Angelov, Dimitar

    2017-06-01

    Genomic DNA is prone to a large number of insults by a myriad of endogenous and exogenous agents. The base excision repair (BER) is the major mechanism used by cells for the removal of various DNA lesions spontaneously or environmentally induced and the maintenance of genome integrity. The presence of persistent DNA damage is not compatible with life, since abrogation of BER leads to early embryonic lethality in mice. There are several lines of evidences showing existence of a link between deficient BER, cancer proneness and ageing, thus illustrating the importance of this DNA repair pathway in human health. Although the enzymology of BER mechanisms has been largely elucidated using chemically defined DNA damage substrates and purified proteins, the complex interplay of BER with another vital process like transcription or when DNA is in its natural state (i.e. wrapped in nucleosome and assembled in chromatin fiber is largely unexplored. Cells use chromatin remodeling factors to overcome the general repression associated with the nucleosomal organization. It is broadly accepted that energy-dependent nucleosome remodeling factors disrupt histones-DNA interactions at the expense of ATP hydrolysis to favor transcription as well as DNA repair. Importantly, unlike transcription, BER is not part of a regulated developmental process but represents a maintenance system that should be efficient anytime and anywhere in the genome. In this review we will discuss how BER can deal with chromatin organization to maintain genetic information. Emphasis will be placed on the following challenging question: how BER is initiated within chromatin? Copyright © 2017 Elsevier Inc. All rights reserved.

  11. Push back to respond better: regulatory inhibition of the DNA double-strand break response.

    Science.gov (United States)

    Panier, Stephanie; Durocher, Daniel

    2013-10-01

    Single DNA lesions such as DNA double-strand breaks (DSBs) can cause cell death or trigger genome rearrangements that have oncogenic potential, and so the pathways that mend and signal DNA damage must be highly sensitive but, at the same time, selective and reversible. When initiated, boundaries must be set to restrict the DSB response to the site of the lesion. The integration of positive and, crucially, negative control points involving post-translational modifications such as phosphorylation, ubiquitylation and acetylation is key for building fast, effective responses to DNA damage and for mitigating the impact of DNA lesions on genome integrity.

  12. Red lesion detection using background estimation and lesions characteristics in diabetic retinal image

    Science.gov (United States)

    Zhang, Dongbo; Peng, Yinghui; Yi, Yao; Shang, Xingyu

    2013-10-01

    Detection of red lesions [hemorrhages (HRs) and microaneurysms (MAs)] is crucial for the diagnosis of early diabetic retinopathy. A method based on background estimation and adapted to specific characteristics of HRs and MAs is proposed. Candidate red lesions are located by background estimation and Mahalanobis distance measure and then some adaptive postprocessing techniques, which include vessel detection, nonvessel exclusion based on shape analysis, and noise points exclusion by double-ring filter (only used for MAs detection), are conducted to remove nonlesion pixels. The method is evaluated on our collected image dataset, and experimental results show that it is better than or approximate to other previous approaches. It is effective to reduce the false-positive and false-negative results that arise from incomplete and inaccurate vessel structure.

  13. NMR structural studies of the ionizing radiation adduct 7-hydro-8-oxodeoxyguanosine (8-oxo-7H-dG) opposite deoxyadenosine in a DNA duplex. 8-oxo-7H-dG(syn)·dA(anti) alignment at lesion site

    International Nuclear Information System (INIS)

    Kouchakdjian, M.; Patel, D.J.; Bodepudi, V.; Shibutani, S.; Eisenberg, M.; Johnson, F.; Grollman, A.P.

    1991-01-01

    Proton NMR studies are reported on the complementary d(C1-C2-A3-C4-T5-A6-oxo-G7-T8-C9-A10-C11-C12)·d(G13-G14-T15-G16-A17-A18-T19-A20-G21-T22-G23-G24) dodecanucleotide duplex (designated 8-oxo-7H-dG·dA 12-mer), which contains a centrally located 7-hydro-8-oxodeoxyguanosine (8-oxo-7H-dG) residue, a group commonly found in DNA that has been exposed to ionizing radiation or oxidizing free radicals. From the NMR spectra it can be deduced that this moiety exists as two tautomers, or gives rise to two DNA conformations, that are in equilibrium and that exchange slowly. The present study focuses on the major component of the equilibrium that originates in the 6,8-dioxo tautomer of 8-oxo-7H-dG. The authors have assigned the exchangeable NH1, NH7, and NH 2 -2 base protons located on the Watson-Crick and Hoogsteen edges of 8-oxo-7H-dG7 in the 8-oxo-7H-dG·dA 12-mer duplex, using an analysis of one- and two-dimensional nuclear Overhauser enhancement (NOE) data in H 2 O solution. They were able to detect a set of intra- and interstrand NOEs between protons (exchangeable and nonexchangeable) on adjacent residues in the d(A6-oxo-G7-T8)·d(A17-A18-T19) trinucleotide segment centered about the lesion site that establishes stacking of the oxo-dG7(syn)·dA(anti) pair between stable Watson-Crick dA6·dT19 and dT8·A17 base pairs with minimal perturbation of the helix. The structural studies demonstrate that 8-oxo-7H-dG(syn)·dA(anti) forms a stable pair in the interior of the helix, providing a basis for the observed incorporation of dA opposite 8-oxo-7H-dG when readthrough occurs past this oxidized nucleoside base

  14. Repair of DNA damage in Deinococcus radiodurans

    International Nuclear Information System (INIS)

    Evans, D.M.

    1984-01-01

    The repair of DNA lesions in Deinococcus radiodurans was examined with particular reference to DNA excision repair of ultraviolet light (UV) induced pyrimidine dimers. The characteristics of excision repair via UV endonucleases α and β in vivo varied with respect to (a) the substrate range of the enzymes, (b) the rate of repair of DNA damage (c) the requirement for a protein synthesised in response to DNA damage to attenuate exonuclease action at repairing regions. UV endonuclease α is postulated to incise DNA in a different manner from UV endonuclease β thus defining the method of subsequent repair. Several DNA damage specific endonuclease activities independent of α and β are described. Mutations of the uvsA, uvsF and uvsG genes resulted in an increase in single-strand breaks in response to DNA damage producing uncontrolled DNA degradation. Evidence is presented that these genes have a role in limiting the access of UV endonuclease β to DNA lesions. uvsF and uvsG are also shown to be linked to the mtoA gene. Mutation of uvsH and reo-1 produces further distinct phenotypes which are discussed. An overall model of excision repair of DNA damage in Deinococcus radiodurans is presented. (author)

  15. DNA oxidation and DNA repair in gills of zebra mussels exposed to cadmium and benzo(a)pyrene.

    Science.gov (United States)

    Michel, Cécile; Vincent-Hubert, Françoise

    2015-11-01

    Freshwater bivalve molluscs are considered as effective indicators of environmental pollution. The comet assay allows the detection of DNA damage such as DNA strand breaks and alkali-labile sites. The main oxidative lesion, 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodG), which is a pre-mutagenic lesion, can be detected by the comet assay coupled with the hOGG1 DNA repair enzyme. With this modified assay we recently observed that BaP induced 8-oxodG lesions and with the modified comet-Fpg assay we observed that Cd induced oxidative DNA damage. The aim of this study was to determine the stability of DNA lesions in Cd and BaP exposed zebra mussels using the comet-hOGG1 assay. Mussels were exposed for 24 h to these two chemicals and then placed in clean water for 6 days. We observed that BaP (7, 12 and 18 µg/L) induced an increase of DNA strand break levels as soon as 6 h of exposure and that the two highest concentrations of BaP induced a low level of hOGG1-sensitive sites. After 2 days of depuration, BaP induced DNA lesions returned to the basal level, indicating an effective DNA repair. Cd (3, 32 and 81 µg/L) induced an increase of the DNA strand break levels and a low level of hOGG1-sensitive sites. This study revealed that BaP-induced DNA lesions are repaired more efficiently than Cd-induced DNA lesions. As the level of hOGG1 sensitive sites was increased in Cd and BaP exposed mussels, it seems that these chemicals induce 8-oxo-dG.

  16. Pre-cancerous (DNA and chromosomal lesions in professional sports

    Directory of Open Access Journals (Sweden)

    Radhika Sharma

    2012-01-01

    Conclusion: Significantly increased genomic instability in players of both sports was observed. Both repaired and repairable genetic damage cells were observed in different tissues of the same subject. The presence of such genetic damage implies that these players are at an individual risk from cancer- and age-related diseases.

  17. Removing Hair Safely

    Science.gov (United States)

    ... For Consumers Home For Consumers Consumer Updates Removing Hair Safely Share Tweet Linkedin Pin it More sharing ... related to common methods of hair removal. Laser Hair Removal In this method, a laser destroys hair ...

  18. DNA adducts in senescent cells

    International Nuclear Information System (INIS)

    Gaubatz, J.W.

    1987-01-01

    Perturbations in DNA repair and other metabolic processes during development and aging might affect the steady-state level of genomic damage. The persistence or accumulation of DNA lesions in postmitotic cells could have a significant impact on proper cellular function, interfering with gene regulation for example. To test the notion that DNA damage increases as a function of age in non-dividing cells, DNA was purified from heart tissue of C57BL/6Nia mice at different ages and analyzed by post labeling techniques to detect DNA adducts. In the present experiments, four-dimensional, thin-layer chromatography was used to isolate aromatic adducts that were labeled with carrier-free (γ- 32 P) ATP under DNA-P excess conditions. The complexity and frequency of aromatic adducts varied between DNA samples. Several adducts were present in all preparations and were clearly more abundant in nucleotide maps of mature and old heart DNA. However, a direct correlation with age was not observed. In contrast, experiments in which aromatic adducts were first isolated by phase-transfer to 1-butanol, then labeled with excess (γ- 32 P)ATP indicated that there was an age-related increase in these adducts. The results are consistent with their earlier studies that showed alkyl adducts increased during aging of mouse myocardium and suggest that a common repair pathway might be involved

  19. Preoperative nonpalpable breast lesions localization

    Energy Technology Data Exchange (ETDEWEB)

    Gardellin, G; Natale, F; Perin, B

    1986-01-01

    The effectiveness of real time sonography and mammography are examined in localizing with a hookwire (introduced via a straight needle) the nonpalpable breast lesions. The method, used for surgery or biopsy, was successful in a series of 13 patients with nonpalpable breast lesions, 4 affectd by carcinoma. 18 refs.

  20. Detection, characterization and measure of a new radiation-induced damage in isolated and cellular DNA; Detection, caracterisation et mesure d'un nouveau dommage radio-induit de l'ADN isole et cellulaire

    Energy Technology Data Exchange (ETDEWEB)

    Regulus, P

    2006-10-15

    Deoxyribonucleic acid (DNA) contains the genetic information and chemical injury to this macromolecule may have severe biological consequences. We report here the detection of 4 new radiation-induced DNA lesions by using a high-performance liquid chromatography coupled to tandem mass spectrometry (HPLC-MS/MS) approach. For that purpose, the characteristic fragmentation of most 2'-deoxy-ribo nucleosides, the loss of 116 Da corresponding to the loss of the 2-deoxyribose moiety, was used in the so-called neutral loss mode of the HPLC-MS/MS. One of the newly detected lesions, named dCyd341 because it is a 2'-deoxycytidine modification exhibiting a molecular weight of 341 Da, was also detected in cellular DNA. Characterization of this modified nucleoside was performed using NMR and exact mass determination of the product obtained by chemical synthesis. A mechanism of formation was then proposed, in which the first event is the H-abstraction at the C4 position of a 2-deoxyribose moiety. Then, the sugar modification produced exhibits a reactive aldehyde that, through reaction with a vicinal cytosine base, gives rise to dCyd341. dCyd341 could be considered as a complex damage since its formation involves a DNA strand break and a cross-link between a damaged sugar residue and a vicinal cytosine base located most probably on the complementary DNA strand. In addition to its characterization, preliminary biological studies revealed that cells are able to remove the lesion from DNA. Repair studies have revealed the ability of cells to excise the lesion. Identification of the repair systems involved could represent an interesting challenge. (author)

  1. Human telomeres are hypersensitive to UV-induced DNA Damage and refractory to repair.

    Directory of Open Access Journals (Sweden)

    Patrick J Rochette

    2010-04-01

    Full Text Available Telomeric repeats preserve genome integrity by stabilizing chromosomes, a function that appears to be important for both cancer and aging. In view of this critical role in genomic integrity, the telomere's own integrity should be of paramount importance to the cell. Ultraviolet light (UV, the preeminent risk factor in skin cancer development, induces mainly cyclobutane pyrimidine dimers (CPD which are both mutagenic and lethal. The human telomeric repeat unit (5'TTAGGG/CCCTAA3' is nearly optimal for acquiring UV-induced CPD, which form at dipyrimidine sites. We developed a ChIP-based technique, immunoprecipitation of DNA damage (IPoD, to simultaneously study DNA damage and repair in the telomere and in the coding regions of p53, 28S rDNA, and mitochondrial DNA. We find that human telomeres in vivo are 7-fold hypersensitive to UV-induced DNA damage. In double-stranded oligonucleotides, this hypersensitivity is a property of both telomeric and non-telomeric repeats; in a series of telomeric repeat oligonucleotides, a phase change conferring UV-sensitivity occurs above 4 repeats. Furthermore, CPD removal in the telomere is almost absent, matching the rate in mitochondria known to lack nucleotide excision repair. Cells containing persistent high levels of telomeric CPDs nevertheless proliferate, and chronic UV irradiation of cells does not accelerate telomere shortening. Telomeres are therefore unique in at least three respects: their biophysical UV sensitivity, their prevention of excision repair, and their tolerance of unrepaired lesions. Utilizing a lesion-tolerance strategy rather than repair would prevent double-strand breaks at closely-opposed excision repair sites on opposite strands of a damage-hypersensitive repeat.

  2. DNA2—An Important Player in DNA Damage Response or Just Another DNA Maintenance Protein?

    Directory of Open Access Journals (Sweden)

    Elzbieta Pawłowska

    2017-07-01

    Full Text Available The human DNA2 (DNA replication helicase/nuclease 2 protein is expressed in both the nucleus and mitochondria, where it displays ATPase-dependent nuclease and helicase activities. DNA2 plays an important role in the removing of long flaps in DNA replication and long-patch base excision repair (LP-BER, interacting with the replication protein A (RPA and the flap endonuclease 1 (FEN1. DNA2 can promote the restart of arrested replication fork along with Werner syndrome ATP-dependent helicase (WRN and Bloom syndrome protein (BLM. In mitochondria, DNA2 can facilitate primer removal during strand-displacement replication. DNA2 is involved in DNA double strand (DSB repair, in which it is complexed with BLM, RPA and MRN for DNA strand resection required for homologous recombination repair. DNA2 can be a major protein involved in the repair of complex DNA damage containing a DSB and a 5′ adduct resulting from a chemical group bound to DNA 5′ ends, created by ionizing radiation and several anticancer drugs, including etoposide, mitoxantrone and some anthracyclines. The role of DNA2 in telomere end maintenance and cell cycle regulation suggests its more general role in keeping genomic stability, which is impaired in cancer. Therefore DNA2 can be an attractive target in cancer therapy. This is supported by enhanced expression of DNA2 in many cancer cell lines with oncogene activation and premalignant cells. Therefore, DNA2 can be considered as a potential marker, useful in cancer therapy. DNA2, along with PARP1 inhibition, may be considered as a potential target for inducing synthetic lethality, a concept of killing tumor cells by targeting two essential genes.

  3. Visualization of complex DNA damage along accelerated ions tracks

    Science.gov (United States)

    Kulikova, Elena; Boreyko, Alla; Bulanova, Tatiana; Ježková, Lucie; Zadneprianetc, Mariia; Smirnova, Elena

    2018-04-01

    The most deleterious DNA lesions induced by ionizing radiation are clustered DNA double-strand breaks (DSB). Clustered or complex DNA damage is a combination of a few simple lesions (single-strand breaks, base damage etc.) within one or two DNA helix turns. It is known that yield of complex DNA lesions increases with increasing linear energy transfer (LET) of radiation. For investigation of the induction and repair of complex DNA lesions, human fibroblasts were irradiated with high-LET 15N ions (LET = 183.3 keV/μm, E = 13MeV/n) and low-LET 60Co γ-rays (LET ≈ 0.3 keV/μm) radiation. DNA DSBs (γH2AX and 53BP1) and base damage (OGG1) markers were visualized by immunofluorecence staining and high-resolution microscopy. The obtained results showed slower repair kinetics of induced DSBs in cells irradiated with accelerated ions compared to 60Co γ-rays, indicating induction of more complex DNA damage. Confirming previous assumptions, detailed 3D analysis of γH2AX/53BP1 foci in 15N ions tracks revealed more complicated structure of the foci in contrast to γ-rays. It was shown that proteins 53BP1 and OGG1 involved in repair of DNA DSBs and modified bases, respectively, were colocalized in tracks of 15N ions and thus represented clustered DNA DSBs.

  4. Afterloading technique for interstitial irradiation of lesions in deep-seated organs

    International Nuclear Information System (INIS)

    Kitagawa, T.; Kakehi, M.; Kunieda, T.; Tsukiyama, I.; Hamada, M.; Inakoshi, H.; Sakudo, M.; Suemasu, K.; Matsumoto, K.; Yoneyama, T.; Iizuka, T.; Nomura, K.; Kawachi, K.

    1982-01-01

    An afterloading procedure using 192 Ir seeds was developed for the control of both localized primary lesions that are difficult to remove and superficial residual lesions that remain after the partial removal of tumors in relatively inaccessible, deep-seated organs. This technique makes possible the delivery of a minimal radiation dose to lesions in deep-seated organs. Fewer complications result, the seeds can be adjusted at appropriate intervals in proportion to the amount of radioactivity desired, and radiation exposure to personnel can be reduced. This paper describes the techniques and apparatus used to place the seeds in the tubing. Primary lesions of the urinary bladder, the prostate gland, and the esophagus, residual lesions in the brain and lung, and metastases in intrapelvic lymph nodes were treated. No technical difficulties or complications were encountered. Radiation exposures to personnel were minimized. The results indicate that the procedure has practical applications

  5. DNA damage in plant herbarium tissue.

    Science.gov (United States)

    Staats, Martijn; Cuenca, Argelia; Richardson, James E; Vrielink-van Ginkel, Ria; Petersen, Gitte; Seberg, Ole; Bakker, Freek T

    2011-01-01

    Dried plant herbarium specimens are potentially a valuable source of DNA. Efforts to obtain genetic information from this source are often hindered by an inability to obtain amplifiable DNA as herbarium DNA is typically highly degraded. DNA post-mortem damage may not only reduce the number of amplifiable template molecules, but may also lead to the generation of erroneous sequence information. A qualitative and quantitative assessment of DNA post-mortem damage is essential to determine the accuracy of molecular data from herbarium specimens. In this study we present an assessment of DNA damage as miscoding lesions in herbarium specimens using 454-sequencing of amplicons derived from plastid, mitochondrial, and nuclear DNA. In addition, we assess DNA degradation as a result of strand breaks and other types of polymerase non-bypassable damage by quantitative real-time PCR. Comparing four pairs of fresh and herbarium specimens of the same individuals we quantitatively assess post-mortem DNA damage, directly after specimen preparation, as well as after long-term herbarium storage. After specimen preparation we estimate the proportion of gene copy numbers of plastid, mitochondrial, and nuclear DNA to be 2.4-3.8% of fresh control DNA and 1.0-1.3% after long-term herbarium storage, indicating that nearly all DNA damage occurs on specimen preparation. In addition, there is no evidence of preferential degradation of organelle versus nuclear genomes. Increased levels of C→T/G→A transitions were observed in old herbarium plastid DNA, representing 21.8% of observed miscoding lesions. We interpret this type of post-mortem DNA damage-derived modification to have arisen from the hydrolytic deamination of cytosine during long-term herbarium storage. Our results suggest that reliable sequence data can be obtained from herbarium specimens.

  6. DNA typing by capillary electrophoresis

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, N.

    1997-10-08

    Capillary electrophoresis is becoming more and more important in nucleic acid analysis including DNA sequencing, typing and disease gene measurements. This work summarized the background of DNA typing. The recent development of capillary electrophoresis was also discussed. The second part of the thesis showed the principle of DNA typing based on using the allelic ladder as the absolute standard ladder in capillary electrophoresis system. Future work will be focused on demonstrating DNA typing on multiplex loci and examples of disease diagnosis in the on-line format of PCR-CE. Also capillary array electrophoresis system should allow high throughput, fast speed DNA typing. Only the introduction and conclusions for this report are available here. A reprint was removed for separate processing.

  7. Cytotoxicity of alkylating agents towards sensitive and resistant strains of Escherichia coli in relation to extent and mode of alkylation of cellular macromolecules and repair of alkylation lesions in deoxyribonucleic acids.

    Science.gov (United States)

    Lawley, P D; Brookes, P

    1968-09-01

    1. A quantitative study was made of the relationship between survival of colony-forming ability in Escherichia coli strains B/r and B(s-1) and the extents of alkylation of cellular DNA, RNA and protein after treatment with mono- or di-functional sulphur mustards, methyl methanesulphonate or iodoacetamide. 2. The mustards and methyl methanesulphonate react with nucleic acids in the cells, in the same way as found previously from chemical studies in vitro, and with proteins. Iodoacetamide reacts only with protein, principally with the thiol groups of cysteine residues. 3. The extents of alkylation of cellular constituents required to prevent cell division vary widely according to the strain of bacteria and the nature of the alkylating agent. 4. The extents of alkylation of the sensitive and resistant strains at a given dose of alkylating agent do not differ significantly. 5. Removal of alkyl groups from DNA of cells of the resistant strains B/r and 15T(-) after alkylation with difunctional sulphur mustard was demonstrated; the product di(guanin-7-ylethyl) sulphide, characteristic of di- as opposed to mono-functional alkylation, was selectively removed; the time-scale of this effect suggests an enzymic rather than a chemical mechanism. 6. The sensitive strain B(s-1) removed alkyl groups from DNA in this way only at very low extents of alkylation. When sensitized to mustard action by treatment with iodoacetamide, acriflavine or caffeine, the extent of alkylation of cellular DNA corresponding to a mean lethal dose was decreased to approximately 3 molecules of di(guanin-7-ylethyl) sulphide in the genome of this strain. 7. Relatively large numbers of monofunctional alkylations per genome can be withstood by this sensitive strain. Iodoacetamide had the weakest cytotoxic action of the agents investigated; methyl methanesulphonate was significantly weaker in effect than the monofunctional sulphur mustard, which was in turn weaker than the difunctional sulphur mustard. 8

  8. DNA repair is indispensable for survival after acute inflammation

    Science.gov (United States)

    Calvo, Jennifer A.; Meira, Lisiane B.; Lee, Chun-Yue I.; Moroski-Erkul, Catherine A.; Abolhassani, Nona; Taghizadeh, Koli; Eichinger, Lindsey W.; Muthupalani, Sureshkumar; Nordstrand, Line M.; Klungland, Arne; Samson, Leona D.

    2012-01-01

    More than 15% of cancer deaths worldwide are associated with underlying infections or inflammatory conditions, therefore understanding how inflammation contributes to cancer etiology is important for both cancer prevention and treatment. Inflamed tissues are known to harbor elevated etheno-base (ε-base) DNA lesions induced by the lipid peroxidation that is stimulated by reactive oxygen and nitrogen species (RONS) released from activated neutrophils and macrophages. Inflammation contributes to carcinogenesis in part via RONS-induced cytotoxic and mutagenic DNA lesions, including ε-base lesions. The mouse alkyl adenine DNA glycosylase (AAG, also known as MPG) recognizes such base lesions, thus protecting against inflammation-associated colon cancer. Two other DNA repair enzymes are known to repair ε-base lesions, namely ALKBH2 and ALKBH3; thus, we sought to determine whether these DNA dioxygenase enzymes could protect against chronic inflammation-mediated colon carcinogenesis. Using established chemically induced colitis and colon cancer models in mice, we show here that ALKBH2 and ALKBH3 provide cancer protection similar to that of the DNA glycosylase AAG. Moreover, Alkbh2 and Alkbh3 each display apparent epistasis with Aag. Surprisingly, deficiency in all 3 DNA repair enzymes confers a massively synergistic phenotype, such that animals lacking all 3 DNA repair enzymes cannot survive even a single bout of chemically induced colitis. PMID:22684101

  9. Oxidative DNA damage and its repair in rat spleen following subchronic exposure to aniline

    International Nuclear Information System (INIS)

    Ma Huaxian; Wang Jianling; Abdel-Rahman, Sherif Z.; Boor, Paul J.; Khan, M. Firoze

    2008-01-01

    The mechanisms by which aniline exposure elicits splenotoxic response, especially the tumorigenic response, are not well-understood. Splenotoxicity of aniline is associated with iron overload and generation of reactive oxygen species (ROS) which can cause oxidative damage to DNA, proteins and lipids (oxidative stress). 8-Hydroxy-2'-deoxyguanosine (8-OHdG) is one of the most abundant oxidative DNA lesions resulting from ROS, and 8-oxoguanine glycosylase 1 (OGG1), a specific DNA glycosylase/lyase enzyme, plays a key role in the removal of 8-OHdG adducts. This study focused on examining DNA damage (8-OHdG) and repair (OGG1) in the spleen in an experimental condition preceding a tumorigenic response. To achieve that, male Sprague-Dawley rats were subchronically exposed to aniline (0.5 mmol/kg/day via drinking water for 30 days), while controls received drinking water only. Aniline treatment led to a significant increase in splenic oxidative DNA damage, manifested as a 2.8-fold increase in 8-OHdG levels. DNA repair activity, measured as OGG1 base excision repair (BER) activity, increased by ∼ 1.3 fold in the nuclear protein extracts (NE) and ∼ 1.2 fold in the mitochondrial protein extracts (ME) of spleens from aniline-treated rats as compared to the controls. Real-time PCR analysis for OGG1 mRNA expression in the spleen revealed a 2-fold increase in expression in aniline-treated rats than the controls. Likewise, OGG1 protein expression in the NEs of spleens from aniline-treated rats was ∼ 1.5 fold higher, whereas in the MEs it was ∼ 1.3 fold higher than the controls. Aniline treatment also led to stronger immunostaining for both 8-OHdG and OGG1 in the spleens, confined to the red pulp areas. It is thus evident from our studies that aniline-induced oxidative stress is associated with increased oxidative DNA damage. The BER pathway was also activated, but not enough to prevent the accumulation of oxidative DNA damage (8-OHdG). Accumulation of mutagenic oxidative

  10. DNA Camouflage

    Science.gov (United States)

    2016-01-08

    1 DNA Camouflage Supplementary Information Bijan Zakeri1,2*, Timothy K. Lu1,2*, Peter A. Carr2,3* 1Department of Electrical Engineering and...ll.mit.edu). Distribution A: Public Release   2 Supplementary Figure 1 DNA camouflage with the 2-state device. (a) In the presence of Cre, DSD-2[α...10 1 + Cre 1 500 1,000 length (bp) chromatogram alignment template − Cre   4 Supplementary Figure 3 DNA camouflage with a switchable

  11. Photorepair and excision repair removal of UV-induced pyrimidine dimers and (6-4) photoproducts in the tail fin of the Medaka, Oryzias latipes

    International Nuclear Information System (INIS)

    Funayama, Tomoo; Mitani, Hiroshi; Shima, Akihiro; Ishigaki, Yasuhito; Matsunaga, Tsukasa; Nikaido, Osamu.

    1994-01-01

    Induction and repair of UV-B induced DNA damage in the tail fin of the Medaka, were examined immunohistochemically and by the enzyme-linked immunosorbent assay (ELISA). UV-induced DNA damage was detected only in the outermost layer of epithelial cells and did not differ in fishes having different degree of melanization. Both pyrimidine dimers and (6-4) photoproducts in the fin cells were removed by excision repair in the dark, the excision of (6-4) photoproducts being about twice as efficient as that of pyrimidine dimers. The rate of excision repair of UV-induced lesions in fin tissue was three to four times that in cultured Medaka cells, OL32.. In the fin cells, reductions in the numbers of pyrimidine dimers and (6-4) photoproducts were seen after treatment with fluorescent light, whereas less reductions of pyrimidine dimers and no reductions of (6-4) photoproducts were observed in OL32 cells. (author)

  12. Base excision repair deficient mice lacking the Aag alkyladenine DNA glycosylase.

    NARCIS (Netherlands)

    B.P. Engelward (Bevin); G. Weeda (Geert); M.D. Wyatt; J.L.M. Broekhof (Jose'); J. de Wit (Jan); I. Donker (Ingrid); J.M. Allan (James); B. Gold (Bert); J.H.J. Hoeijmakers (Jan); L.D. Samson (Leona)

    1997-01-01

    textabstract3-methyladenine (3MeA) DNA glycosylases remove 3MeAs from alkylated DNA to initiate the base excision repair pathway. Here we report the generation of mice deficient in the 3MeA DNA glycosylase encoded by the Aag (Mpg) gene. Alkyladenine DNA glycosylase turns out to be the major DNA

  13. DNA damage-induced inflammation and nuclear architecture.

    Science.gov (United States)

    Stratigi, Kalliopi; Chatzidoukaki, Ourania; Garinis, George A

    2017-07-01

    Nuclear architecture and the chromatin state affect most-if not all- DNA-dependent transactions, including the ability of cells to sense DNA lesions and restore damaged DNA back to its native form. Recent evidence points to functional links between DNA damage sensors, DNA repair mechanisms and the innate immune responses. The latter raises the question of how such seemingly disparate processes operate within the intrinsically complex nuclear landscape and the chromatin environment. Here, we discuss how DNA damage-induced immune responses operate within chromatin and the distinct sub-nuclear compartments highlighting their relevance to chronic inflammation. Copyright © 2016 Elsevier Ireland Ltd. All rights reserved.

  14. Association between selected oral pathogens and gastric precancerous lesions.

    Directory of Open Access Journals (Sweden)

    Christian R Salazar

    Full Text Available We examined whether colonization of selected oral pathogens is associated with gastric precancerous lesions in a cross-sectional study. A total of 119 participants were included, of which 37 were cases of chronic atrophic gastritis, intestinal metaplasia, or dysplasia. An oral examination was performed to measure periodontal indices. Plaque and saliva samples were tested with real-time quantitative PCR for DNA levels of pathogens related to periodontal disease (Porphyromonas gingivalis, Tannerella forsythensis, Treponema denticola, Actinobacillus actinomycetemcomitans and dental caries (Streptococcus mutans and S. sobrinus. There were no consistent associations between DNA levels of selected bacterial species and gastric precancerous lesions, although an elevated but non-significant odds ratio (OR for gastric precancerous lesions was observed in relation to increasing colonization of A. actinomycetemcomitans (OR = 1.36 for one standard deviation increase, 95% Confidence Interval = 0.87-2.12, P. gingivalis (OR = 1.12, 0.67-1.88 and T. denticola (OR = 1.34, 0.83-2.12 measured in plaque. To assess the influence of specific long-term infection, stratified analyses by levels of periodontal indices were conducted. A. actinomycetemcomitans was significantly associated with gastric precancerous lesions (OR = 2.51, 1.13-5.56 among those with ≥ median of percent tooth sites with PD ≥ 3 mm, compared with no association among those below the median (OR = 0.86, 0.43-1.72. A significantly stronger relationship was observed between the cumulative bacterial burden score of periodontal disease-related pathogens and gastric precancerous lesions among those with higher versus lower levels of periodontal disease indices (p-values for interactions: 0.03-0.06. Among individuals with periodontal disease, high levels of colonization of periodontal pathogens are associated with an increased risk of gastric precancerous lesions.

  15. Changing activity in MS lesions

    International Nuclear Information System (INIS)

    Kermode, A.G.; Tofts, P.S.; Thompson, A.J.; Rudge, P.; MacManus, D.G.; Kendall, B.E.; Moseley, I.F.; Kingsley, D.P.E.; McDonald, W.I.

    1989-01-01

    Gd-DTPA enhanced T1 weighted MRI is a discriminating test for a defective blood-brain barrier, with MS lesions showing considerable variation in the pattern of enhancement. Since little is known of the changes in the blood-brain barrier in the active plaque over time, the natural history of blood-brain barrier disturbance in the MS lesion was examined to confirm earlier reports that Gd-DTPA enhancement is a consistent early event in new lesions of relapsing/remitting MS. This knowledge is essential for the use of MRI in monitoring treatment. (author). 9 refs

  16. PHAEOHYPHOMYCOSIS: CUTANEOUS, SUBCUTANEOUS, NASOPHARYNGEAL LESIONS

    Directory of Open Access Journals (Sweden)

    M. Rasoolinejad

    1999-06-01

    Full Text Available Phaeohyphomycosis is an amalgam of clinical diseases caused by a wide variety of dematiaceous fungi. We are reporting on a 16 year-old patient from Amol with subcutaneous cervical nodes and nasopharyngeal lesions of phaeohypho"nmycosis that were confirmed by pathological examination, direct smear, and culture. After treatment with an oral triazole (Itraconazole for 4 months, all nodes and lesions disappeared and treatment was stopped A new lesion appeared on his chest wall 8 months, therapy with itraconazole was restarted and commuted for a long time.

  17. OCT investigation of dental lesions

    Science.gov (United States)

    Osiac, Eugen; Popescu, Sanda Mihaela; Scrieciu, Monica; Mercuţ, Rǎzvan; Mercuţ, Veronica; Vǎtu, Mihaela

    2018-03-01

    There are several important non carious lesions affecting the tooth structure, lesions which may be classified into four clinical forms of dental wear: abfraction, erosion, attrition and abrasion, and different types of root resorption. Search for new, non-invasive and fast methods able to detect and describe such injuries is of utmost importance. Optical coherence tomography (OCT) proved itself as an appropriate investigation method for several medical fields including ophthalmology, dermatology, cardiology etc. Our study reveals OCT preliminary investigations as a promising tool for detecting and evaluating of the mentioned lesions.

  18. Induction and repair of DNA double strand breaks: The increasing spectrum of non-homologous end joining pathways

    International Nuclear Information System (INIS)

    Mladenov, Emil; Iliakis, George

    2011-01-01

    A defining characteristic of damage induced in the DNA by ionizing radiation (IR) is its clustered character that leads to the formation of complex lesions challenging the cellular repair mechanisms. The most widely investigated such complex lesion is the DNA double strand break (DSB). DSBs undermine chromatin stability and challenge the repair machinery because an intact template strand is lacking to assist restoration of integrity and sequence in the DNA molecule. Therefore, cells have evolved a sophisticated machinery to detect DSBs and coordinate a response on the basis of inputs from various sources. A central function of cellular responses to DSBs is the coordination of DSB repair. Two conceptually different mechanisms can in principle remove DSBs from the genome of cells of higher eukaryotes. Homologous recombination repair (HRR) uses as template a homologous DNA molecule and is therefore error-free; it functions preferentially in the S and G2 phases. Non-homologous end joining (NHEJ), on the other hand, simply restores DNA integrity by joining the two ends, is error prone as sequence is only fortuitously preserved and active throughout the cell cycle. The basis of DSB repair pathway choice remains unknown, but cells of higher eukaryotes appear programmed to utilize preferentially NHEJ. Recent work suggests that when the canonical DNA-PK dependent pathway of NHEJ (D-NHEJ), becomes compromised an alternative NHEJ pathway and not HRR substitutes in a quasi-backup function (B-NHEJ). Here, we outline aspects of DSB induction by IR and review the mechanisms of their processing in cells of higher eukaryotes. We place particular emphasis on backup pathways of NHEJ and summarize their increasing significance in various cellular processes, as well as their potential contribution to carcinogenesis.

  19. Decrease DNA contamination in the laboratories

    DEFF Research Database (Denmark)

    Kampmann, Marie-Louise; Børsting, Claus; Morling, Niels

    2017-01-01

    In this study, we tested various approaches to remove DNA from hard laboratory surfaces. We contaminated clean surfaces with four different concentrations of massively parallel sequencing libraries. The DNA was dried and left for 45 min and for 24 h, respectively, before any treatment. The surfaces.......9–1.8% hypochlorite in order to eliminate laboratory contamination and simultaneously minimise any poisonous gases....

  20. The Intrinsic Fragility of DNA (Nobel Lecture).

    Science.gov (United States)

    Lindahl, Tomas

    2016-07-18

    Our cells contain common molecules, such as water or oxygen, that can damage DNA. In his studies Tomas Lindahl has shown how specific repair enzymes remove and replace damaged parts of DNA in a process of vital importance. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The essential DNA polymerases δ and ε are involved in repair of UV-damaged DNA in the yeast Saccharomyces cerevisiae

    International Nuclear Information System (INIS)

    Halas, A.; Policinska, Z.; Baranowska, H.; Jachymczyk, W.J.

    1999-01-01

    We have studied the ability of yeast DNA polymerases to carry out repair of lesions caused by UV irradiation in Saccharomyces cerevisiae. By the analysis of postirradiation relative molecular mass changes in cellular DNA of different DNA polymerases mutant strains, it was established that mutations in DNA polymerases δ and ε showed accumulation of single-strand breaks indicating defective repair. Mutations in other DNA polymerase genes exhibited no defects in DNA repair. Thus, the data obtained suggest that DNA polymerases δ and ε are both necessary for DNA replication and for repair of lesions caused by UV irradiation. The results are discussed in the light of current concepts concerning the specificity of DNA polymerases in DNA repair. (author)

  2. DNA damage responses in human induced pluripotent stem cells and embryonic stem cells.

    Directory of Open Access Journals (Sweden)

    Olga Momcilovic

    2010-10-01

    Full Text Available Induced pluripotent stem (iPS cells have the capability to undergo self-renewal and differentiation into all somatic cell types. Since they can be produced through somatic cell reprogramming, which uses a defined set of transcription factors, iPS cells represent important sources of patient-specific cells for clinical applications. However, before these cells can be used in therapeutic designs, it is essential to understand their genetic stability.Here, we describe DNA damage responses in human iPS cells. We observe hypersensitivity to DNA damaging agents resulting in rapid induction of apoptosis after γ-irradiation. Expression of pluripotency factors does not appear to be diminished after irradiation in iPS cells. Following irradiation, iPS cells activate checkpoint signaling, evidenced by phosphorylation of ATM, NBS1, CHEK2, and TP53, localization of ATM to the double strand breaks (DSB, and localization of TP53 to the nucleus of NANOG-positive cells. We demonstrate that iPS cells temporary arrest cell cycle progression in the G(2 phase of the cell cycle, displaying a lack of the G(1/S cell cycle arrest similar to human embryonic stem (ES cells. Furthermore, both cell types remove DSB within six hours of γ-irradiation, form RAD51 foci and exhibit sister chromatid exchanges suggesting homologous recombination repair. Finally, we report elevated expression of genes involved in DNA damage signaling, checkpoint function, and repair of various types of DNA lesions in ES and iPS cells relative to their differentiated counterparts.High degrees of similarity in DNA damage responses between ES and iPS cells were found. Even though reprogramming did not alter checkpoint signaling following DNA damage, dramatic changes in cell cycle structure, including a high percentage of cells in the S phase, increased radiosensitivity and loss of DNA damage-induced G(1/S cell cycle arrest, were observed in stem cells generated by induced pluripotency.

  3. Differential recruitment of DNA Ligase I and III to DNA repair sites

    Science.gov (United States)

    Mortusewicz, Oliver; Rothbauer, Ulrich; Cardoso, M. Cristina; Leonhardt, Heinrich

    2006-01-01

    DNA ligation is an essential step in DNA replication, repair and recombination. Mammalian cells contain three DNA Ligases that are not interchangeable although they use the same catalytic reaction mechanism. To compare the recruitment of the three eukaryotic DNA Ligases to repair sites in vivo we introduced DNA lesions in human cells by laser microirradiation. Time lapse microscopy of fluorescently tagged proteins showed that DNA Ligase III accumulated at microirradiated sites before DNA Ligase I, whereas we could detect only a faint accumulation of DNA Ligase IV. Recruitment of DNA Ligase I and III to repair sites was cell cycle independent. Mutational analysis and binding studies revealed that DNA Ligase I was recruited to DNA repair sites by interaction with PCNA while DNA Ligase III was recruited via its BRCT domain mediated interaction with XRCC1. Selective recruitment of specialized DNA Ligases may have evolved to accommodate the particular requirements of different repair pathways and may thus enhance efficiency of DNA repair. PMID:16855289

  4. DNA Damage, Mutagenesis and Cancer

    Directory of Open Access Journals (Sweden)

    Ashis K. Basu

    2018-03-01

    Full Text Available A large number of chemicals and several physical agents, such as UV light and γ-radiation, have been associated with the etiology of human cancer. Generation of DNA damage (also known as DNA adducts or lesions induced by these agents is an important first step in the process of carcinogenesis. Evolutionary processes gave rise to DNA repair tools that are efficient in repairing damaged DNA; yet replication of damaged DNA may take place prior to repair, particularly when they are induced at a high frequency. Damaged DNA replication may lead to gene mutations, which in turn may give rise to altered proteins. Mutations in an oncogene, a tumor-suppressor gene, or a gene that controls the cell cycle can generate a clonal cell population with a distinct advantage in proliferation. Many such events, broadly divided into the stages of initiation, promotion, and progression, which may occur over a long period of time and transpire in the context of chronic exposure to carcinogens, can lead to the induction of human cancer. This is exemplified in the long-term use of tobacco being responsible for an increased risk of lung cancer. This mini-review attempts to summarize this wide area that centers on DNA damage as it relates to the development of human cancer.

  5. Structural basis for the initiation of eukaryotic transcription-coupled DNA repair.

    Science.gov (United States)

    Xu, Jun; Lahiri, Indrajit; Wang, Wei; Wier, Adam; Cianfrocco, Michael A; Chong, Jenny; Hare, Alissa A; Dervan, Peter B; DiMaio, Frank; Leschziner, Andres E; Wang, Dong

    2017-11-30

    Eukaryotic transcription-coupled repair (TCR) is an important and well-conserved sub-pathway of nucleotide excision repair that preferentially removes DNA lesions from the template strand that block translocation of RNA polymerase II (Pol II). Cockayne syndrome group B (CSB, also known as ERCC6) protein in humans (or its yeast orthologues, Rad26 in Saccharomyces cerevisiae and Rhp26 in Schizosaccharomyces pombe) is among the first proteins to be recruited to the lesion-arrested Pol II during the initiation of eukaryotic TCR. Mutations in CSB are associated with the autosomal-recessive neurological disorder Cockayne syndrome, which is characterized by progeriod features, growth failure and photosensitivity. The molecular mechanism of eukaryotic TCR initiation remains unclear, with several long-standing unanswered questions. How cells distinguish DNA lesion-arrested Pol II from other forms of arrested Pol II, the role of CSB in TCR initiation, and how CSB interacts with the arrested Pol II complex are all unknown. The lack of structures of CSB or the Pol II-CSB complex has hindered our ability to address these questions. Here we report the structure of the S. cerevisiae Pol II-Rad26 complex solved by cryo-electron microscopy. The structure reveals that Rad26 binds to the DNA upstream of Pol II, where it markedly alters its path. Our structural and functional data suggest that the conserved Swi2/Snf2-family core ATPase domain promotes the forward movement of Pol II, and elucidate key roles for Rad26 in both TCR and transcription elongation.

  6. DNA repair in bacterial cultures and plasmid DNA exposed to infrared laser for treatment of pain

    International Nuclear Information System (INIS)

    Canuto, K S; Sergio, L P S; Marciano, R S; Guimarães, O R; Polignano, G A C; Geller, M; Fonseca, A S; Paoli, F

    2013-01-01

    Biostimulation of tissues by low intensity lasers has been described on a photobiological basis and clinical protocols are recommended for treatment of various diseases, but their effects on DNA are controversial. The objective of this work was to evaluate effects of low intensity infrared laser exposure on survival and bacterial filamentation in Escherichia coli cultures, and induction of DNA lesions in bacterial plasmids. In E. coli cultures and plasmids exposed to an infrared laser at fluences used to treat pain, bacterial survival and filamentation and DNA lesions in plasmids were evaluated by electrophoretic profile. Data indicate that the infrared laser (i) increases survival of E. coli wild type in 24 h of stationary growth phase, (ii) induces bacterial filamentation, (iii) does not alter topological forms of plasmids and (iv) does not alter the electrophoretic profile of plasmids incubated with exonuclease III or formamidopyrimidine DNA glycosylase. A low intensity infrared laser at the therapeutic fluences used to treat pain can alter survival of E. coli wild type, induce filamentation in bacterial cells, depending on physiologic conditions and DNA repair, and induce DNA lesions other than single or double DNA strand breaks or alkali-labile sites, which are not targeted by exonuclease III or formamidopyrimidine DNA glycosylase. (letter)

  7. Inhibiting DNA Polymerases as a Therapeutic Intervention against Cancer

    Directory of Open Access Journals (Sweden)

    Anthony J. Berdis

    2017-11-01

    Full Text Available Inhibiting DNA synthesis is an important therapeutic strategy that is widely used to treat a number of hyperproliferative diseases including viral infections, autoimmune disorders, and cancer. This chapter describes two major categories of therapeutic agents used to inhibit DNA synthesis. The first category includes purine and pyrmidine nucleoside analogs that directly inhibit DNA polymerase activity. The second category includes DNA damaging agents including cisplatin and chlorambucil that modify the composition and structure of the nucleic acid substrate to indirectly inhibit DNA synthesis. Special emphasis is placed on describing the molecular mechanisms of these inhibitory effects against chromosomal and mitochondrial DNA polymerases. Discussions are also provided on the mechanisms associated with resistance to these therapeutic agents. A primary focus is toward understanding the roles of specialized DNA polymerases that by-pass DNA lesions produced by DNA damaging agents. Finally, a section is provided that describes emerging areas in developing new therapeutic strategies targeting specialized DNA polymerases.

  8. Ionizing radiation sensitivity of DNA polymerase lambda-deficient cells.

    NARCIS (Netherlands)

    Vermeulen, C.; Bertocci, B.; Begg, A.C.; Vens, C.

    2007-01-01

    Ionizing radiation induces a diverse spectrum of DNA lesions, including strand breaks and oxidized bases. In mammalian cells, ionizing radiation-induced lesions are targets of non-homologous end joining, homologous recombination, and base excision repair. In vitro assays show a potential involvement

  9. DNA glue

    DEFF Research Database (Denmark)

    Filichev, Vyacheslav V; Astakhova, Irina V.; Malakhov, Andrei D.

    2008-01-01

    Significant alterations in thermal stability of parallel DNA triplexes and antiparallel duplexes were observed upon changing the attachment of ethynylpyrenes from para to ortho in the structure of phenylmethylglycerol inserted as a bulge into DNA (TINA). Insertions of two ortho-TINAs as a pseudo...

  10. Hyperstretching DNA

    NARCIS (Netherlands)

    Schakenraad, Koen; Biebricher, Andreas S.; Sebregts, Maarten; Ten Bensel, Brian; Peterman, Erwin J.G.; Wuite, Gijs J L; Heller, Iddo; Storm, Cornelis; Van Der Schoot, Paul

    2017-01-01

    The three-dimensional structure of DNA is highly susceptible to changes by mechanical and biochemical cues in vivo and in vitro. In particular, large increases in base pair spacing compared to regular B-DNA are effected by mechanical (over)stretching and by intercalation of compounds that are widely

  11. Post-radiotherapeutic heart lesions

    International Nuclear Information System (INIS)

    Testart, F.M.

    1979-05-01

    Heart structures have traditionally been considered radioresistant. In fact all tissues subjected to radiotherapy can develop lesions. Possible damage includes: - pericardiac fibrosis, the commonest and best individualized, associated with a constriction this leads to a stoppage pattern usually occurring late, around the 18th month. Its frequency depends directly on the total radiation dose; - fibrous myocarditis by direct damage to the heart muscle; - stenosis type lesions of the large coronary trunks; - in exceptional cases lesions of the aorta: hyperplastic degenerescence of the intima and adventitia or of the aortic sigmoid valvules and the mitral valves. Three observations are reported, concerning a coronary, a pericardiac and a coronary, myocardiac and pericardiac lesion. Following this account the irradiation techniques and main experimental data are reviewed and the prophylactic and therapeutic consequences to be derived from our observations and those of the literature are examined [fr

  12. Atypical idiopathic inflammatory demyelinating lesions

    DEFF Research Database (Denmark)

    Wallner-Blazek, Mirja; Rovira, Alex; Fillipp, Massimo

    2013-01-01

    Atypical lesions of a presumably idiopathic inflammatory demyelinating origin present quite variably and may pose diagnostic problems. The subsequent clinical course is also uncertain. We, therefore, wanted to clarify if atypical idiopathic inflammatory demyelinating lesions (AIIDLs) can be class......Atypical lesions of a presumably idiopathic inflammatory demyelinating origin present quite variably and may pose diagnostic problems. The subsequent clinical course is also uncertain. We, therefore, wanted to clarify if atypical idiopathic inflammatory demyelinating lesions (AIIDLs) can...... be classified according to previously suggested radiologic characteristics and how this classification relates to prognosis. Searching the databases of eight tertiary referral centres we identified 90 adult patients (61 women, 29 men; mean age 34 years) with ≥1 AIIDL. We collected their demographic, clinical...

  13. Molecular characterization of poxviruses associated with tattoo skin lesions in UK cetaceans.

    Directory of Open Access Journals (Sweden)

    Barbara A Blacklaws

    Full Text Available There is increasing concern for the well-being of cetacean populations around the UK. Tattoo skin disease (characterised by irregular, grey, black or yellowish, stippled cutaneous lesions caused by poxvirus infection is a potential health indicatora potential health indicator for cetaceans. Limited sequence data indicates that cetacean poxviruses (CPVs belong to an unassigned genus of the Chordopoxvirinae. To obtain further insight into the phylogenetic relationships between CPV and other Chordopoxvirinae members we partially characterized viral DNA originating from tattoo lesions collected in Delphinidae and Phocoenidae stranded along the UK coastline in 1998-2008. We also evaluated the presence of CPV in skin lesions other than tattoos to examine specificity and sensitivity of visual diagnosis. After DNA extraction, regions of the DNA polymerase and DNA topoisomerase I genes were amplified by PCR, sequenced and compared with other isolates. The presence of CPV DNA was demonstrated in tattoos from one striped dolphin (Stenella coeruleoalba, eight harbour porpoises (Phocoena phocoena and one short-beaked common dolphin (Delphinus delphis and in one 'dubious tattoo' lesion detected in one other porpoise. Seventeen of the 18 PCR positive skin lesions had been visually identified as tattoos and one as a dubious tattoo. None of the other skin lesions were PCR positive. Thus, visual identification had a 94.4% sensitivity and 100% specificity. The DNA polymerase PCR was most effective in detecting CPV DNA. Limited sequence phylogeny grouped the UK samples within the odontocete poxviruses (CPV group 1 and indicated that two different poxvirus lineages infect the Phocoenidae and the Delphinidae. The phylogenetic tree had three major branches: one with the UK Phocoenidae viruses, one with the Delphinidae isolates and one for the mysticete poxvirus (CPV group 2. This implies a radiation of poxviruses according to the host suborder and the families within

  14. Recovery of subchromosomal DNA synthesis in synchronous V-79 Chinese hamster cells after ultraviolet light exposure

    International Nuclear Information System (INIS)

    Meechan, P.J.; Carpenter, J.G.

    1986-01-01

    Previous work obtained from Chinese hamster V-79 cells indicated that, immediately following exposure, UV-induced lesions acted as blocks to elongation of nascent strands, but gradually lost that ability over a 10 h period after exposure to 10 J/m 2 . The work reported herein attempted to examine possible cell cycle mediated alterations in the recovery of DNA synthesis. Kinetic incorporation of radiolabeled thymidine studies indicated that there may have been a more rapid recover of DNA synthesis in cells irradiated in G 1 or G 2 vs cells irradiated in S phase. DNA fiber autoradiograms prepared from synchronous cells indicated that after irradiation in any phase of the cell cycle, the length of newly synthesized DNA was equal to control lengths 1 h after exposure to 5.0Jm 2 (or 1 h after entering S phase for cells irradiated in G 1 or G 2 ). This observed recovery was not solely due to an excision process. No cell cycle mediated difference in the number of dimers induced or removed as a function of cell cycle position was observed. These results appear to be consistent with a continuum of effects, with initiation effects dominating the response at low fluences, gapped synthesis at intermediate fluences and elongation inhibition at high fluences. The fluences at which each event dominates may be cell-line specific. (author)

  15. True Lies: The Double Life of the Nucleotide Excision Repair Factors in Transcription and DNA Repair

    Directory of Open Access Journals (Sweden)

    Nicolas Le May

    2010-01-01

    Full Text Available Nucleotide excision repair (NER is a major DNA repair pathway in eukaryotic cells. NER removes structurally diverse lesions such as pyrimidine dimers, arising upon UV irradiation or bulky chemical adducts, arising upon exposure to carcinogens and some chemotherapeutic drugs. NER defects lead to three genetic disorders that result in predisposition to cancers, accelerated aging, neurological and developmental defects. During NER, more than 30 polypeptides cooperate to recognize, incise, and excise a damaged oligonucleotide from the genomic DNA. Recent papers reveal an additional and unexpected role for the NER factors. In the absence of a genotoxic attack, the promoters of RNA polymerases I- and II-dependent genes recruit XPA, XPC, XPG, and XPF to initiate gene expression. A model that includes the growth arrest and DNA damage 45α protein (Gadd45α and the NER factors, in order to maintain the promoter of active genes under a hypomethylated state, has been proposed but remains controversial. This paper focuses on the double life of the NER factors in DNA repair and transcription and describes the possible roles of these factors in the RNA synthesis process.

  16. Study of DNA reconstruction enzymes

    Energy Technology Data Exchange (ETDEWEB)

    Sekiguchi, M [Kyushu Univ., Fukuoka (Japan). Faculty of Science

    1976-12-01

    Description was made of the characteristics and mechanism of 3 reconstructive enzymes which received from M. luteus or E. coli or T4, and of which natures were clarified as reconstructive enzymes of DNA irradiated with ultraviolet rays. As characteristics, the site of breaking, reaction, molecular weight, electric charge in the neutrality and a specific adhesion to DNA irradiated with ultraviolet rays were mentioned. As to mutant of ultraviolet ray sensitivity, hereditary control mechanism of removal and reconstruction by endo-nuclease activation was described, and suggestion was referred to removal and reconstruction of cells of xedoderma pigmentosum which is a hereditary disease of human. Description was also made as to the mechanism of exonuclease activation which separates dimer selectively from irradiated DNA.

  17. MRI atlas of MS lesions

    Energy Technology Data Exchange (ETDEWEB)

    Sahraian, Mohammad Ali [Tehran Univ. of Medical Sciences Sina Hospital (Iran). Dept. of Neurology; Radue, Ernst-Wilhelm [Univ. Hospital Basel (Switzerland). Dept. of Neuroradiology

    2008-07-01

    MRI has become the main paraclinical test in the diagnosis and management of multiple sclerosis. We have demonstrated more than 400 pictures of different typical and atypical MS lesions in this atlas. Each image has a teaching point. New diagnostic criteria and differential diagnosis are discussed and the book is supported by a teaching DVD where the reader can see MS lesions in different slices and sequences. (orig.)

  18. ARSENIC REMOVAL BY IRON REMOVAL PROCESSES

    Science.gov (United States)

    Presentation will discuss the removal of arsenic from drinking water using iron removal processes that include oxidation/filtration and the manganese greensand processes. Presentation includes results of U.S. EPA field studies conducted in Michigan and Ohio on existing iron remo...

  19. The Bacterial Flora of Incipient Occlusal Lesions in Naval Recruits.

    Science.gov (United States)

    1980-07-01

    fissures while providing an improved method of studying the microbiota of this aspect of the tooth, creates an artificial environment for bacterial...independent examiner. An oral examination and a radiographic review were performed on all subjects prior to fissure removal to verify the suitability...classification of a lesion as incipient. Teeth requiring cavity preparations deeper than 0.5 mm beyond the DEJ or not requiring penetration of the dentin

  20. DNA Dosimetry Assessment for Sunscreen Genotoxic Photoprotection

    OpenAIRE

    Schuch, André Passaglia; Lago, Juliana Carvalhães; Yagura, Teiti; Menck, Carlos Frederico Martins

    2012-01-01

    Background: Due to the increase of solar ultraviolet radiation (UV) incidence over the last few decades, the use of sunscreen has been widely adopted for skin protection. However, considering the high efficiency of sunlight-induced DNA lesions, it is critical to improve upon the current approaches that are used to evaluate protection factors. An alternative approach to evaluate the photoprotection provided by sunscreens against daily UV radiation-induced DNA damage is provided by the systemat...

  1. Histomorphological spetrum of breast lesions.

    Science.gov (United States)

    Parajuli, S; Koirala, U; Khatri, R; Acharya, L; Suwal, A

    2011-04-01

    Cancer of the breast is the second most common cause of cancer in women. Mass in the breast, whether benign or malignant is a cause of anxiety to the patients and the family members. All breast lumps are considered to be carcinomas until proved otherwise and are the causes of concern both for the patient and surgeon. This is a retrospective study conducted in Kathmandu Model Hospital for a total duration of three years from August 2007 to August 2010. 114 sample of breast tissue sent for histopathology were studied. Peak incidence of benign lesion was in between 21-30 years and malignant lesions in between 31-50 years. No breast lesions were seen in the first decade of life. Cancer of the breast was seen in 12.28% of cases. Fibroadenoma and fibrocystic disease were the commonest benign lesion and infiltrating ductal carcinoma was the commonest malignant lesion. Specimens from 10 male breasts were received. Gynaecomastia was the most common lesion encountered in males. Infiltrating ductal carcinoma was seen in a 70 year old male. Breast cancer is one of the commonest causes of breast lump particularly in women and is growing public health problem in Nepal.

  2. Removal of misincorporated ribonucleotides from prokaryotic genomes: an unexpected role for nucleotide excision repair.

    Directory of Open Access Journals (Sweden)

    Alexandra Vaisman

    2013-11-01

    Full Text Available Stringent steric exclusion mechanisms limit the misincorporation of ribonucleotides by high-fidelity DNA polymerases into genomic DNA. In contrast, low-fidelity Escherichia coli DNA polymerase V (pol V has relatively poor sugar discrimination and frequently misincorporates ribonucleotides. Substitution of a steric gate tyrosine residue with alanine (umuC_Y11A reduces sugar selectivity further and allows pol V to readily misincorporate ribonucleotides as easily as deoxynucleotides, whilst leaving its poor base-substitution fidelity essentially unchanged. However, the mutability of cells expressing the steric gate pol V mutant is very low due to efficient repair mechanisms that are triggered by the misincorporated rNMPs. Comparison of the mutation frequency between strains expressing wild-type and mutant pol V therefore allows us to identify pathways specifically directed at ribonucleotide excision repair (RER. We previously demonstrated that rNMPs incorporated by umuC_Y11A are efficiently removed from DNA in a repair pathway initiated by RNase HII. Using the same approach, we show here that mismatch repair and base excision repair play minimal back-up roles in RER in vivo. In contrast, in the absence of functional RNase HII, umuC_Y11A-dependent mutagenesis increases significantly in ΔuvrA, uvrB5 and ΔuvrC strains, suggesting that rNMPs misincorporated into DNA are actively repaired by nucleotide excision repair (NER in vivo. Participation of NER in RER was confirmed by reconstituting ribonucleotide-dependent NER in vitro. We show that UvrABC nuclease-catalyzed incisions are readily made on DNA templates containing one, two, or five rNMPs and that the reactions are stimulated by the presence of mispaired bases. Similar to NER of DNA lesions, excision of rNMPs proceeds through dual incisions made at the 8(th phosphodiester bond 5' and 4(th-5(th phosphodiester bonds 3' of the ribonucleotide. Ribonucleotides misinserted into DNA can therefore be

  3. E2F1 interactions with hHR23A inhibit its degradation and promote DNA repair.

    Science.gov (United States)

    Singh, Randeep K; Dagnino, Lina

    2016-05-03

    Nucleotide excision repair (NER) is a major mechanism for removal of DNA lesions induced by exposure to UV radiation in the epidermis. Recognition of damaged DNA sites is the initial step in their repair, and requires multiprotein complexes that contain XPC and hHR23 proteins, or their orthologues. A variety of transcription factors are also involved in NER, including E2F1. In epidermal keratinocytes, UV exposure induces E2F1 phosphorylation, which allows it to recruit various NER factors to sites of DNA damage. However, the relationship between E2F1 and hHR23 proteins vis-à-vis NER has remained unexplored. We now show that E2F1 and hHR23 proteins can interact, and this interaction stabilizes E2F1, inhibiting its proteasomal degradation. Reciprocally, E2F1 regulates hHR23A subcellular localization, recruiting it to sites of DNA photodamage. As a result, E2F1 and hHR23A enhance DNA repair following exposure to UV radiation, contributing to genomic stability in the epidermis.

  4. FFA STUDY OF MACULAR LESIONS

    Directory of Open Access Journals (Sweden)

    K. Vinayagamurthy

    2017-08-01

    Full Text Available BACKGROUND Macula is an important portion of retina that occupies the posterior pole of retina. Any disease that affects macula results in significant loss of central vision, form vision and colour vision to an extent. Macular lesions can be hereditary as well as acquired. Macular lesions occur in both younger and older individuals. Anatomically, a macular lesions can vary from a simple lesion like an RPF defect to a vision-threatening lesions like choroidal neovascular membrane. Many screening tests that are sensitive and specific are available to assess the functioning of macula called as ‘macular function test’. But, the greater understanding of the retinal vascular led to the usage of fluorescein angiogram in the detection and screening of macular, retinovascular and optic disc lesions. Through fundus fluorescein angiogram is a thirty-year-old procedure; it is still in vogue in almost all parts of the world. It has its own merits. The aim of the study is to study the role of fluorescein angiography in the evaluation of macular lesions. MATERIALS AND METHODS A hospital-based prospective randomised study was done, which included 50 patients. Detailed patient history was taken and thorough ocular and systemic examination was done. All patients were examined by ophthalmoscopy (direct and indirect and slit-lamp examination with 90D followed by fluorescein angiography. Ophthalmoscopic and fluorescein angiography findings were analysed and categorised. Patients were advised proper ocular and systemic treatment and follow up. RESULTS 50 cases with macular lesions were analysed and categorised into conditions like ARMD, CSR, macular oedema, CME, degenerations and dystrophies and miscellaneous conditions. FFA altered the diagnosis in 8% cases and categorised the cases in all cases. 16% patients developed adverse reactions like allergy, vomiting and nausea. On statistical analysis, FFA proved to be cheap and superior diagnostic tool in confirming

  5. DNA probes

    International Nuclear Information System (INIS)

    Castelino, J.

    1992-01-01

    The creation of DNA probes for detection of specific nucleotide segments differs from ligand detection in that it is a chemical rather than an immunological reaction. Complementary DNA or RNA is used in place of the antibody and is labelled with 32 P. So far, DNA probes have been successfully employed in the diagnosis of inherited disorders, infectious diseases, and for identification of human oncogenes. The latest approach to the diagnosis of communicable and parasitic infections is based on the use of deoxyribonucleic acid (DNA) probes. The genetic information of all cells is encoded by DNA and DNA probe approach to identification of pathogens is unique because the focus of the method is the nucleic acid content of the organism rather than the products that the nucleic acid encodes. Since every properly classified species has some unique nucleotide sequences that distinguish it from every other species, each organism's genetic composition is in essence a finger print that can be used for its identification. In addition to this specificity, DNA probes offer other advantages in that pathogens may be identified directly in clinical specimens

  6. DNA probes

    Energy Technology Data Exchange (ETDEWEB)

    Castelino, J

    1993-12-31

    The creation of DNA probes for detection of specific nucleotide segments differs from ligand detection in that it is a chemical rather than an immunological reaction. Complementary DNA or RNA is used in place of the antibody and is labelled with {sup 32}P. So far, DNA probes have been successfully employed in the diagnosis of inherited disorders, infectious diseases, and for identification of human oncogenes. The latest approach to the diagnosis of communicable and parasitic infections is based on the use of deoxyribonucleic acid (DNA) probes. The genetic information of all cells is encoded by DNA and DNA probe approach to identification of pathogens is unique because the focus of the method is the nucleic acid content of the organism rather than the products that the nucleic acid encodes. Since every properly classified species has some unique nucleotide sequences that distinguish it from every other species, each organism`s genetic composition is in essence a finger print that can be used for its identification. In addition to this specificity, DNA probes offer other advantages in that pathogens may be identified directly in clinical specimens 10 figs, 2 tabs

  7. Base excision repair of chemotherapeutically-induced alkylated DNA damage predominantly causes contractions of expanded GAA repeats associated with Friedreich's ataxia.

    Directory of Open Access Journals (Sweden)

    Yanhao Lai

    Full Text Available Expansion of GAA·TTC repeats within the first intron of the frataxin gene is the cause of Friedreich's ataxia (FRDA, an autosomal recessive neurodegenerative disorder. However, no effective treatment for the disease has been developed as yet. In this study, we explored a possibility of shortening expanded GAA repeats associated with FRDA through chemotherapeutically-induced DNA base lesions and subsequent base excision repair (BER. We provide the first evidence that alkylated DNA damage induced by temozolomide, a chemotherapeutic DNA damaging agent can induce massive GAA repeat contractions/deletions, but only limited expansions in FRDA patient lymphoblasts. We showed that temozolomide-induced GAA repeat instability was mediated by BER. Further characterization of BER of an abasic site in the context of (GAA20 repeats indicates that the lesion mainly resulted in a large deletion of 8 repeats along with small expansions. This was because temozolomide-induced single-stranded breaks initially led to DNA slippage and the formation of a small GAA repeat loop in the upstream region of the damaged strand and a small TTC loop on the template strand. This allowed limited pol β DNA synthesis and the formation of a short 5'-GAA repeat flap that was cleaved by FEN1, thereby leading to small repeat expansions. At a later stage of BER, the small template loop expanded into a large template loop that resulted in the formation of a long 5'-GAA repeat flap. Pol β then performed limited DNA synthesis to bypass the loop, and FEN1 removed the long repeat flap ultimately causing a large repeat deletion. Our study indicates that chemotherapeutically-induced alkylated DNA damage can induce large contractions/deletions of expanded GAA repeats through BER in FRDA patient cells. This further suggests the potential of developing chemotherapeutic alkylating agents to shorten expanded GAA repeats for treatment of FRDA.

  8. Recruitment of DNA methyltransferase I to DNA repair sites

    Science.gov (United States)

    Mortusewicz, Oliver; Schermelleh, Lothar; Walter, Joachim; Cardoso, M. Cristina; Leonhardt, Heinrich

    2005-01-01

    In mammalian cells, the replication of genetic and epigenetic information is directly coupled; however, little is known about the maintenance of epigenetic information in DNA repair. Using a laser microirradiation system to introduce DNA lesions at defined subnuclear sites, we tested whether the major DNA methyltransferase (Dnmt1) or one of the two de novo methyltransferases (Dnmt3a, Dnmt3b) are recruited to sites of DNA repair in vivo. Time lapse microscopy of microirradiated mammalian cells expressing GFP-tagged Dnmt1, Dnmt3a, or Dnmt3b1 together with red fluorescent protein-tagged proliferating cell nuclear antigen (PCNA) revealed that Dnmt1 and PCNA accumulate at DNA damage sites as early as 1 min after irradiation in S and non-S phase cells, whereas recruitment of Dnmt3a and Dnmt3b was not observed. Deletion analysis showed that Dnmt1 recruitment was mediated by the PCNA-binding domain. These data point to a direct role of Dnmt1 in the restoration of epigenetic information during DNA repair. PMID:15956212

  9. Toehold-mediated strand displacement reaction-dependent fluorescent strategy for sensitive detection of uracil-DNA glycosylase activity.

    Science.gov (United States)

    Wu, Yushu; Wang, Lei; Jiang, Wei

    2017-03-15

    Sensitive detection of uracil-DNA glycosylase (UDG) activity is beneficial for evaluating the repairing process of DNA lesions. Here, toehold-mediated strand displacement reaction (TSDR)-dependent fluorescent strategy was constructed for sensitive detection of UDG activity. A single-stranded DNA (ssDNA) probe with two uracil bases and a trigger sequence were designed. A hairpin probe with toehold domain was designed, and a reporter probe was also designed. Under the action of UDG, two uracil bases were removed from ssDNA probe, generating apurinic/apyrimidinic (AP) sites. Then, the AP sites could inhibit the TSDR between ssDNA probe and hairpin probe, leaving the trigger sequence in ssDNA probe still free. Subsequently, the trigger sequence was annealed with the reporter probe, initiating the polymerization and nicking amplification reaction. As a result, numerous G-quadruplex (G4) structures were formed, which could bind with N-methyl-mesoporphyrin IX (NMM) to generate enhanced fluorescent signal. In the absence of UDG, the ssDNA probe could hybridize with the toehold domain of the hairpin probe to initiate TSDR, blocking the trigger sequence, and then the subsequent amplification reaction would not occur. The proposed strategy was successfully implemented for detecting UDG activity with a detection limit of 2.7×10 -5 U/mL. Moreover, the strategy could distinguish UDG well from other interference enzymes. Furthermore, the strategy was also applied for detecting UDG activity in HeLa cells lysate with low effect of cellular components. These results indicated that the proposed strategy offered a promising tool for sensitive quantification of UDG activity in UDG-related function study and disease prognosis. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Not All Erythema Migrans Lesions Are Lyme Disease.

    Science.gov (United States)

    Goddard, Jerome

    2017-02-01

    Lyme disease is the number one arthropod-transmitted disease in the US, and one of the diagnostic criteria for the illness is development of an erythematous bull's-eye rash around a tick bite that may expand over time, hence the term erythema migrans. However, there are other erythema migrans-like rashes, such as those from a condition known as southern tick-associated rash illness. This article describes a patient with an erythema migrans-like lesion similar to that associated with Lyme disease, resulting from a bite by a nymphal-stage lone star tick, Amblyomma americanum. A tick removed from the center of an erythema migrans-like lesion in a patient was identified to species and then submitted to the Centers for Disease Control and Prevention for testing for the agent of Lyme disease, Borrelia burgdorferi. The patient was evaluated by an internist 7 weeks later. After another 3 weeks, the patient's blood was tested serologically for Lyme disease by American Esoteric Laboratories, Memphis, Tenn. Both the tick and human blood sample from this patient were negative for evidence of Lyme disease. Clinically, other than the erythema migrans-like lesion, the patient displayed no signs or symptoms consistent with Lyme disease. This case presents clinical, serological, and molecular evidence that erythema migrans lesions may occur after tick bites in patients and that these lesions may not be due to infection with the agent of Lyme disease. Copyright © 2016 Elsevier Inc. All rights reserved.

  11. DNA translocation by human uracil DNA glycosylase: the case of single-stranded DNA and clustered uracils.

    Science.gov (United States)

    Schonhoft, Joseph D; Stivers, James T

    2013-04-16

    Human uracil DNA glycosylase (hUNG) plays a central role in DNA repair and programmed mutagenesis of Ig genes, requiring it to act on sparsely or densely spaced uracil bases located in a variety of contexts, including U/A and U/G base pairs, and potentially uracils within single-stranded DNA (ssDNA). An interesting question is whether the facilitated search mode of hUNG, which includes both DNA sliding and hopping, changes in these different contexts. Here we find that hUNG uses an enhanced local search mode when it acts on uracils in ssDNA, and also, in a context where uracils are densely clustered in duplex DNA. In the context of ssDNA, hUNG performs an enhanced local search by sliding with a mean sliding length larger than that of double-stranded DNA (dsDNA). In the context of duplex DNA, insertion of high-affinity abasic product sites between two uracil lesions serves to significantly extend the apparent sliding length on dsDNA from 4 to 20 bp and, in some cases, leads to directionally biased 3' → 5' sliding. The presence of intervening abasic product sites mimics the situation where hUNG acts iteratively on densely spaced uracils. The findings suggest that intervening product sites serve to increase the amount of time the enzyme remains associated with DNA as compared to nonspecific DNA, which in turn increases the likelihood of sliding as opposed to falling off the DNA. These findings illustrate how the search mechanism of hUNG is not predetermined but, instead, depends on the context in which the uracils are located.

  12. Intramedullary cavernous angiomas of the spinal cord. Clinical characteristics of 13 lesions

    International Nuclear Information System (INIS)

    Aoyama, Takeshi; Hida, Kazutoshi; Houkin, Kiyohiro

    2011-01-01

    Magnetic resonance imaging has increased the incidence of the diagnosis of intramedullary cavernous angioma. Surgical therapy tends not to be recommended for asymptomatic lesions, but symptomatic lesions that bleed recurrently should be treated. The natural course of intramedullary cavernous angioma remains unknown and arguments have been raised against the surgical treatment of symptomatic lesions. We reviewed the clinical features of 13 intramedullary cavernous angiomas in 12 patients surgically treated between 1988 and 2009. The 7 men and 5 women were aged from 14 to 60 years, the preoperative interval ranged from 0 to 161 months, and the mean number of hemorrhages in the 13 lesions was 2.5. Sixteen operations were performed to treat the 13 lesions. The surgical approach depended on the lesion location. The outcome of patients with mild to moderate preoperative symptoms (McCormick grades I-III) was significantly better than that of patients with severe symptoms (McCormick grade IV) (p<0.05). Symptomatic intramedullary cavernous angioma tends to bleed repeatedly. The lesion should be surgically removed to avoid further deterioration due to recurrent hemorrhages. The shortest path approach should be selected based on preoperative images and complete removal should be attempted. Residual lesion may be masked by surrounding gliosis, so careful postoperative follow up is necessary. (author)

  13. US-guided preoperative hook-wire localization of nonpalpable breast lesions

    International Nuclear Information System (INIS)

    Shin, Tae Beom; Lee, Sang Kwon; Kim, Hye Jung; Ryeom, Hun Kyu; Kim, Tae Hun; Kim, Yong Ju; Kang, Duk Sik; Lee, Young Ha; Park, Ho Yong

    2000-01-01

    To evaluate the feasibility and efficacy of US-guided preoperative wire localization of nonpalpable breast lesions. US-guided preoperative wire localization was performed upon 45 nonpalpable breast lesions including 14 nonpalpable masses, 11 nonpalpable masses with microcalcifications, 11 ductal lesions, 9 with microcalcifications. No local anesthesia was performed during the localization procedure. Under the US-guidance, the needle with the hook-wire was inserted into the lesion until the hook of the wire reached 1 cm beyond the posterior margin of the lesion. Precise wire positioning was confirmed by mammography. Specimen radiography or specimen ultrasonography was performed in all cases. US-guided preoperative wire localization was successfully achieved in all cases. The time required for US-guided wire localization was less than five minutes. All lesions were successfully removed by surgical excision. Successful removal was confirmed by specimen radiography or specimen ultrasonography, gross findings of the specimen and consistency between radiographic and pathologic findings. The histologic diagnosis of 45 lesions were 7 ductal carcinoma in situ, 8 invasive ductal carcinoma, 6 fibroadenoma, 8 intraductal papilloma, 2 atypical ductal hyperplasia, and 14 fibrocystic changes. No complications were occurred during and after the procedure. US-guided preoperative wire localization for excisional biopsy is simple, safe, and accurate method in the histologic diagnosis of nonpalpable breast lesions detectable with ultrasonography.

  14. US-guided preoperative hook-wire localization of nonpalpable breast lesions

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Tae Beom; Lee, Sang Kwon; Kim, Hye Jung; Ryeom, Hun Kyu; Kim, Tae Hun; Kim, Yong Ju; Kang, Duk Sik; Lee, Young Ha; Park, Ho Yong [Kyungpook National University College of Medicine, Taegu (Korea, Republic of)

    2000-12-15

    To evaluate the feasibility and efficacy of US-guided preoperative wire localization of nonpalpable breast lesions. US-guided preoperative wire localization was performed upon 45 nonpalpable breast lesions including 14 nonpalpable masses, 11 nonpalpable masses with microcalcifications, 11 ductal lesions, 9 with microcalcifications. No local anesthesia was performed during the localization procedure. Under the US-guidance, the needle with the hook-wire was inserted into the lesion until the hook of the wire reached 1 cm beyond the posterior margin of the lesion. Precise wire positioning was confirmed by mammography. Specimen radiography or specimen ultrasonography was performed in all cases. US-guided preoperative wire localization was successfully achieved in all cases. The time required for US-guided wire localization was less than five minutes. All lesions were successfully removed by surgical excision. Successful removal was confirmed by specimen radiography or specimen ultrasonography, gross findings of the specimen and consistency between radiographic and pathologic findings. The histologic diagnosis of 45 lesions were 7 ductal carcinoma in situ, 8 invasive ductal carcinoma, 6 fibroadenoma, 8 intraductal papilloma, 2 atypical ductal hyperplasia, and 14 fibrocystic changes. No complications were occurred during and after the procedure. US-guided preoperative wire localization for excisional biopsy is simple, safe, and accurate method in the histologic diagnosis of nonpalpable breast lesions detectable with ultrasonography.

  15. Metatranscriptomics reveals overall active bacterial composition in caries lesions

    Directory of Open Access Journals (Sweden)

    Aurea Simón-Soro

    2014-10-01

    Full Text Available Background: Identifying the microbial species in caries lesions is instrumental to determine the etiology of dental caries. However, a significant proportion of bacteria in carious lesions have not been cultured, and the use of molecular methods has been limited to DNA-based approaches, which detect both active and inactive or dead microorganisms. Objective: To identify the RNA-based, metabolically active bacterial composition of caries lesions at different stages of disease progression in order to provide a list of potential etiological agents of tooth decay. Design: Non-cavitated enamel caries lesions (n=15 and dentin caries lesions samples (n=12 were collected from 13 individuals. RNA was extracted and cDNA was constructed, which was used to amplify the 16S rRNA gene. The resulting 780 bp polymerase chain reaction products were pyrosequenced using Titanium-plus chemistry, and the sequences obtained were used to determine the bacterial composition. Results: A mean of 4,900 sequences of the 16S rRNA gene with an average read length of 661 bp was obtained per sample, giving a comprehensive view of the active bacterial communities in caries lesions. Estimates of bacterial diversity indicate that the microbiota of cavities is highly complex, each sample containing between 70 and 400 metabolically active species. The composition of these bacterial consortia varied among individuals and between caries lesions of the same individuals. In addition, enamel and dentin lesions had a different bacterial makeup. Lactobacilli were found almost exclusively in dentin cavities. Streptococci accounted for 40% of the total active community in enamel caries, and 20% in dentin caries. However, Streptococcus mutans represented only 0.02–0.73% of the total bacterial community. Conclusions: The data indicate that the etiology of dental caries is tissue dependent and that the disease has a clear polymicrobial origin. The low proportion of mutans streptococci

  16. Spider Vein Removal

    Science.gov (United States)

    Spider veins: How are they removed? I have spider veins on my legs. What options are available ... M.D. Several options are available to remove spider veins — thin red lines or weblike networks of ...

  17. DNA methylation

    DEFF Research Database (Denmark)

    Williams, Kristine; Christensen, Jesper; Helin, Kristian

    2012-01-01

    DNA methylation is involved in key cellular processes, including X-chromosome inactivation, imprinting and transcriptional silencing of specific genes and repetitive elements. DNA methylation patterns are frequently perturbed in human diseases such as imprinting disorders and cancer. The recent...... discovery that the three members of the TET protein family can convert 5-methylcytosine (5mC) into 5-hydroxymethylcytosine (5hmC) has provided a potential mechanism leading to DNA demethylation. Moreover, the demonstration that TET2 is frequently mutated in haematopoietic tumours suggests that the TET...... proteins are important regulators of cellular identity. Here, we review the current knowledge regarding the function of the TET proteins, and discuss various mechanisms by which they contribute to transcriptional control. We propose that the TET proteins have an important role in regulating DNA methylation...

  18. DNA data

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Raw DNA chromatogram data produced by the ABI 373, 377, 3130 and 3730 automated sequencing machines in ABI format. These are from fish (primarily Sebastes spp.,...

  19. DNA nanotechnology

    Science.gov (United States)

    Seeman, Nadrian C.; Sleiman, Hanadi F.

    2018-01-01

    DNA is the molecule that stores and transmits genetic information in biological systems. The field of DNA nanotechnology takes this molecule out of its biological context and uses its information to assemble structural motifs and then to connect them together. This field has had a remarkable impact on nanoscience and nanotechnology, and has been revolutionary in our ability to control molecular self-assembly. In this Review, we summarize the approaches used to assemble DNA nanostructures and examine their emerging applications in areas such as biophysics, diagnostics, nanoparticle and protein assembly, biomolecule structure determination, drug delivery and synthetic biology. The introduction of orthogonal interactions into DNA nanostructures is discussed, and finally, a perspective on the future directions of this field is presented.

  20. MRI of the stener lesion

    International Nuclear Information System (INIS)

    Haramati, N.; Hiller, N.; Dowdle, J.; Jacobson, M.; Barax, C.N.; Lieberfarb, R.I.; Lester, B.; Kulick, R.G.

    1995-01-01

    Six cadaver thumbs had ulnar collateral ligament (UCL) tears created surgically. MR examinations (2D STIR and 3D GRASS) were performed identically on all specimens both before displacement (non-Stener) and after displacement (Stener lesion) of the UCL. The MR images were then randomly numbered. Each image was evaluated separately in blinded fashion by four musculoskeletal radiologists for the presence or absence of a Stener lesion. Each radiologist reinterpreted the images after an interval of several days. The interpretation was based on previously published criteria for Stener lesion diagnosis by MR. The sensitivity of GRASS ranged from 0.17 to 0.67 with the most experienced reader scoring the lowest. The specificity of GRASS ranged from 0.33 to 1.0 (most experienced reader 0.67, 0.83). STIR had a sensitivity of 0.00-0.17 and a specificity of 0.53-0.83. The K values for inter- and intraobserver agreement were measured. The intraobserver K for GRASS was 0.27-0.75 (most experienced reader 0.75). 2D imaging is probably inadequate for the evaluation of Stener lesions. The most likely reason is that the STIR slice thickness of 3 mm limits resolution of small UCLs. The poor sensitivity and specificity of GRASS as well as poor interobserver agreement suggest that MR may not be sufficiently accurate for Stener lesion evaluation. (orig./MG)

  1. Cortical stimulation of language fields under local anesthesia: optimizing removal of brain lesions adjacent to speech areas Mapeamento cortical da fala com o paciente acordado: optimização para ressecção de lesões intracranianas localizadas próximas a área da fala

    Directory of Open Access Journals (Sweden)

    Robson Luis Oliveira de Amorim

    2008-09-01

    Full Text Available OBJECTIVE: The main objective when resecting benign brain lesions is to minimize risk of postoperative neurological deficits. We have assessed the safety and effectiveness of craniotomy under local anesthesia and monitored conscious sedation for the resection of lesions involving eloquent language cortex. METHODS: A retrospective review was performed on a consecutive series of 12 patients who underwent craniotomy under local anesthesia between 2001 and 2004. All patients had lesions close to the speech cortex. All resection was verified by post-operative imaging. Six subjects were male and 6 female, and were aged between 14 and 52 years. RESULTS: Lesions comprised 7 tumour lesions, 3 cavernomas and 1 dermoid cyst. Radiological gross total resection was achieved in 66% of patients while remaining cases had greater than 80% resection. Only one patient had a post-operative permanent deficit, whilst another had a transient post-operative deficit. All patients with uncontrollable epilepsy had good outcomes after surgery. None of our cases subsequently needed to be put under general anesthesia. CONCLUSION: Awake craniotomy with brain mapping is a safe technique and the "gold standard" for resection of lesions involving language areas.OBJETIVO: O presente estudo visa discutir as vantagens e as limitacões do uso da técnica de mapeamento cortical da área da fala com o paciente acordado. MÉTODO: esta é uma revisão retrospectiva dos casos em que foi realizado monitoramento cortical intraoperatório em cirurgias para ressecção de lesões intracranianas localizadas próximas à área da fala. Todos os pacientes foram submetidos a avaliação neuropsicológica no pré e intra-operatório. O grau das ressecções foi verificado através de exames de imagem pós-operatórios. Foram avaliados um total de 12 pacientes. Destes, 6 eram do sexo masculino e 6 do feminino. RESULTADOS: 7 lesões eram tumorais. A ressecção total foi atingida em 66% e ressec

  2. Replisome-mediated Translesion Synthesis and Leading Strand Template Lesion Skipping Are Competing Bypass Mechanisms*

    Science.gov (United States)

    Gabbai, Carolina B.; Yeeles, Joseph T. P.; Marians, Kenneth J.

    2014-01-01

    A number of different enzymatic pathways have evolved to ensure that DNA replication can proceed past template base damage. These pathways include lesion skipping by the replisome, replication fork regression followed by either correction of the damage and origin-independent replication restart or homologous recombination-mediated restart of replication downstream of the lesion, and bypass of the damage by a translesion synthesis DNA polymerase. We report here that of two translesion synthesis polymerases tested, only DNA polymerase IV, not DNA polymerase II, could engage productively with the Escherichia coli replisome to bypass leading strand template damage, despite the fact that both enzymes are shown to be interacting with the replicase. Inactivation of the 3′ → 5′ proofreading exonuclease of DNA polymerase II did not enable bypass. Bypass by DNA polymerase IV required its ability to interact with the β clamp and act as a translesion polymerase but did not require its “little finger” domain, a secondary region of interaction with the β clamp. Bypass by DNA polymerase IV came at the expense of the inherent leading strand lesion skipping activity of the replisome, indicating that they are competing reactions. PMID:25301949

  3. PLANNING YOUR REMOVALS

    CERN Multimedia

    Service déménagement; ST Division

    1999-01-01

    To give you better service and avoid lengthy delays, the Removals Service advises you to refrain from programming moves between 26 July and 3 September, as large-scale removals are already planned during this summer period.Thanking you in advance for your co-operation and understanding.Removals Service STTel. 74185 / Mobile 164017

  4. PROGRAMMING OFFICE REMOVALS

    CERN Multimedia

    Groupe ST-HM

    2000-01-01

    The Removals Service recommends you to plan your removals well in advance, taking into account the fact that the Transport and Handling Group’s main priority remains the dismantling of LEP and the installation of the LHC. The requests can be made by: http://st.web.cern.ch/st/hm/removal/DEMEE.HTM Thank you for your cooperation.

  5. DNA expressions - A formal notation for DNA

    NARCIS (Netherlands)

    Vliet, Rudy van

    2015-01-01

    We describe a formal notation for DNA molecules that may contain nicks and gaps. The resulting DNA expressions denote formal DNA molecules. Different DNA expressions may denote the same molecule. Such DNA expressions are called equivalent. We examine which DNA expressions are minimal, which

  6. Interstrand cross-links arising from strand breaks at true abasic sites in duplex DNA

    OpenAIRE

    Yang, Zhiyu; Price, Nathan E.; Johnson, Kevin M.; Wang, Yinsheng; Gates, Kent S.

    2017-01-01

    Abstract Interstrand cross-links are exceptionally bioactive DNA lesions. Endogenous generation of interstrand cross-links in genomic DNA may contribute to aging, neurodegeneration, and cancer. Abasic (Ap) sites are common lesions in genomic DNA that readily undergo spontaneous and amine-catalyzed strand cleavage reactions that generate a 2,3-didehydro-2,3-dideoxyribose sugar remnant (3?ddR5p) at the 3?-terminus of the strand break. Interestingly, this strand scission process leaves an electr...

  7. Oncogene-induced senescence is part of the tumorigenesis barrier imposed by DNA damage checkpoints

    DEFF Research Database (Denmark)

    Bartkova, Jirina; Rezaei, Nousin; Liontos, Michalis

    2006-01-01

    Recent studies have indicated the existence of tumorigenesis barriers that slow or inhibit the progression of preneoplastic lesions to neoplasia. One such barrier involves DNA replication stress, which leads to activation of the DNA damage checkpoint and thereby to apoptosis or cell cycle arrest...... and senescence markers cosegregate closely. Thus, senescence in human preneoplastic lesions is a manifestation of oncogene-induced DNA replication stress and, together with apoptosis, provides a barrier to malignant progression....

  8. Damages induced in lambda phage DNA by enzyme-generated triplet acetone

    International Nuclear Information System (INIS)

    Menck, C.F.; Cabral Neto, J.B.; Gomes, R.A.; Faljoni-Alario, A.

    1985-01-01

    Exposure of lambda phage to triplet acetone, generated during the aerobic oxidation of isobutanal by peroxidase, leads to genome lesions. The majority of these lesions are detected as DNA single-strand breaks only in alkaline conditions, so true breaks were not observed. Also, no sites sensitive to UV-endonuclease from Micrococcus luteus were found in DNA from treated phage. The participation of triplet acetone in the generation of such DNA damage is discussed. (Author) [pt

  9. Abfraction lesions reviewed: current concepts

    Directory of Open Access Journals (Sweden)

    Adriana de Fátima Vasconcelos Pereira

    2008-01-01

    Full Text Available Non-carious cervical lesions are characterized by structural loss near the cementoenamel junction, without the presence of caries. Anumber of theories have arisen to explain the etiology of such lesions, although the real causes remain obscure, as is reflected by the contradictory terminology used in the literature. In addition to describing acidic and abrasive processes documented as etiological factors, attention is given to the role of mechanical stress from occlusal load, which is the most accepted theory for the development of abfraction lesions. Considering that tensile stress leads to the failure of restorations in the cervical region and that this is a fruitful area for future research, the present study has highlighted diagnosis, prognosis and the criteria for treatment.

  10. Ultrasonography of chest wall lesion

    Energy Technology Data Exchange (ETDEWEB)

    Park, Cheol Min; Kim, C. H.; Cha, I. H.; Chung, K. B.; Ser, W. H.; Choi, Y. H. [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1989-12-15

    Thirty-one patients with chest wall diseases were studied with ultrasound to evaluate its role in chest wall lesions. There were eight infectious conditions, 9 benign tumors, 11 malignant lesions and 3 miscellaneous cases. Diffuse chest wall thickening with heterogeneous echogenicity and obliteration of subcutaneous fat layer are findings of acute infection. In cases of tuberculous smpyema necessitates, pleural abnormality extended to the chest wall through intercostal space. Benign tumors were well demarcated, except in 4 cases of lipoma/lipomatosis. Malignant lesions showed irregular soft tissue masses, bone destruction, pleural effusion and subcutaneous invasion. Multiple enlarged lymph nodes were also shown. Ultrasound can demonstrate te internal structure, extent, depth and associated findings such as pleural effusion, bone destruction and peripheral lung involvement. Ultrasound is not only safe, non-invasive and an effective diagnostic imaging modality for chest wall disease, but can also guide aspiration or biopsy for pathologic diagnosis

  11. Ultrasonography of chest wall lesion

    International Nuclear Information System (INIS)

    Park, Cheol Min; Kim, C. H.; Cha, I. H.; Chung, K. B.; Ser, W. H.; Choi, Y. H.

    1989-01-01

    Thirty-one patients with chest wall diseases were studied with ultrasound to evaluate its role in chest wall lesions. There were eight infectious conditions, 9 benign tumors, 11 malignant lesions and 3 miscellaneous cases. Diffuse chest wall thickening with heterogeneous echogenicity and obliteration of subcutaneous fat layer are findings of acute infection. In cases of tuberculous smpyema necessitates, pleural abnormality extended to the chest wall through intercostal space. Benign tumors were well demarcated, except in 4 cases of lipoma/lipomatosis. Malignant lesions showed irregular soft tissue masses, bone destruction, pleural effusion and subcutaneous invasion. Multiple enlarged lymph nodes were also shown. Ultrasound can demonstrate te internal structure, extent, depth and associated findings such as pleural effusion, bone destruction and peripheral lung involvement. Ultrasound is not only safe, non-invasive and an effective diagnostic imaging modality for chest wall disease, but can also guide aspiration or biopsy for pathologic diagnosis

  12. The radiology in the solitary bone lesions

    International Nuclear Information System (INIS)

    Veloso, G.A.; Cardoso, V.M.

    1985-01-01

    Three methods of radiologic analysis of the solitary bone lesions are reviewed. 1. Radiological analysis of the lesions with the objective to suppose the histologic type; 2. To appreciate the velocity of growth and aggressiveness of the lesions. 3. To appreciate the biological behaviour of the bone lesions, making the diagnosis necessary for the treatment. (M.A.C.) [pt

  13. Lesions of juxtacortical origin (surface lesions of bone)

    International Nuclear Information System (INIS)

    Kenan, S.; Abdelwahab, I.F.; Klein, M.J.; Hermann, G.; Lewis, M.M.

    1993-01-01

    A large variety of tumor and tumor-like conditions have been shown to originate from the surface of bone. Most surface lesions are associated with periosteal reaction. The periosteum is a multipotential membrane. Its cellular composition may give rise to a variety of both neoplasms and tumor-like conditions. To avoid misinterpretation, the orthopedist, radiologist, and pathologist should be familiar with the entire spectrum of surface lesions. A better understanding of the natural history and biological behavior at different lesional maturity stages and correlation of the history with the radiographic and pathological findings is essential to establish the correct diagnosis. A history of injury of blunt trauma is very important. A stress fracture may produce a periosteal reaction acd callus that can be difficult to distinguish from osteosarcoma. In this review article, the authors wish to describe and define each term by its anatomy and radiographic features while discussing the entire spectrum of surface lesions. All the illustrative cases in this review article have been proven histologically. (orig.)

  14. Localized lesions in secondary syphillis

    International Nuclear Information System (INIS)

    Rasid, N.; Syphilis, S.

    2008-01-01

    The clinical manifestations of secondary syphilis are variable and can mimic many skin diseases, mostly being generalized and symmetrical in distribution. Localized lesions of secondary syphilis are rarely seen in dermatology clinics. We report an unusual presentation wherein a patient had localized lesions over face and soles only. There is a need for increased awareness on the part of physicians to recognize new patterns of syphilitic infection, together with a willingness to consider the diagnosis of syphilis in patients with unusual clinical features. (author)

  15. What Is Mitochondrial DNA?

    Science.gov (United States)

    ... DNA What is mitochondrial DNA? What is mitochondrial DNA? Although most DNA is packaged in chromosomes within ... proteins. For more information about mitochondria and mitochondrial DNA: Molecular Expressions, a web site from the Florida ...

  16. Effects of radiations on DNA and repair of the damage. Progress report, May 1, 1976--March 31, 1977

    International Nuclear Information System (INIS)

    Hutchinson, F.

    1977-01-01

    Last year's report that repair of DNA double-strand breaks from gamma rays occurs in E. coli was verified by additional experiments. Such repair requires recA function and the presence of another DNA molecule of the same base sequence, so it may involve a recombination-like event. Ultraviolet light acting on DNA containing bromouracil produces double-strand breaks by single photochemical events, and a single model can explain this as well as other results. Strains of E. coli which are unusually mutable by bromouracil--uvrE, mutL, mutR, mutS, are defective in mismatch repair. This strengthens the suggestion in last year's report that such mutagenesis occurs when enzymes responsible for the removal of mismatched bases are unable to remove all the mismatches. Ultraviolet mutagenesis of lambda phage may be a useful model for the study of mutagenesis in cells, because the effects of lesions in the gene mutated (i.e., in the phage) and changes in enzyme systems (by treating the host cells) can be examined separately. Quantitative data support this approach

  17. The lateral infratrigeminal transpontine window to deep pontine lesions.

    Science.gov (United States)

    Ferroli, Paolo; Schiariti, Marco; Cordella, Roberto; Boffano, Carlo; Nava, Simone; La Corte, Emanuele; Cavallo, Claudio; Bauer, Dario; Castiglione, Melina; Broggi, Morgan; Acerbi, Francesco; Broggi, Giovanni

    2015-09-01

    Surgery of brainstem lesions is increasingly performed despite the fact that surgical indications and techniques continue to be debated. The deep pons, in particular, continues to be a critical area in which the specific risks related to different surgical strategies continue to be examined. With the intention of bringing new knowledge into this important arena, the authors systematically examined the results of brainstem surgeries that have been performed through the lateral infratrigeminal transpontine window. Between 1990 and 2013, 29 consecutive patients underwent surgery through this window for either biopsy sampling or for removal of a deep pontine lesion. All of this work was performed at the Department of Neurosurgery of the Istituto Nazionale Neurologico "Carlo Besta", in Milan, Italy. A retrospective analysis of the findings was conducted with the intention of bringing further clarity to this important surgical strategy. The lateral infratrigeminal transpontine window was exposed through 4 different approaches: 1) classic retrosigmoid (15 cases), 2) minimally invasive keyhole retrosigmoid (10 cases), 3) translabyrinthine (1 case), and 4) combined petrosal (3 cases). No deaths occurred during the entire clinical study. The surgical complications that were observed included hydrocephalus (2 cases) and CSF leakage (1 case). In 6 (20.7%) of 29 patients the authors encountered new neurological deficits during the immediate postoperative period. All 6 of these patients had undergone lesion removal. In only 2 of these 6 patients were permanent sequelae observed at 3 months follow-up. These findings show that 93% of the patients studied did not report any permanent worsening of their neurological condition after this surgical intervention. This retrospective study supports the idea that the lateral infratrigeminal transpontine window is both a low-risk and safe corridor for either biopsy sampling or for removal of deep pontine lesions.

  18. DNA dosimetry assessment for sunscreen genotoxic photoprotection.

    Directory of Open Access Journals (Sweden)

    André Passaglia Schuch

    Full Text Available Due to the increase of solar ultraviolet radiation (UV incidence over the last few decades, the use of sunscreen has been widely adopted for skin protection. However, considering the high efficiency of sunlight-induced DNA lesions, it is critical to improve upon the current approaches that are used to evaluate protection factors. An alternative approach to evaluate the photoprotection provided by sunscreens against daily UV radiation-induced DNA damage is provided by the systematic use of a DNA dosimeter.The Sun Protection Factor for DNA (DNA-SPF is calculated by using specific DNA repair enzymes, and it is defined as the capacity for inhibiting the generation of cyclobutane pyrimidine dimers (CPD and oxidised DNA bases compared with unprotected control samples. Five different commercial brands of sunscreen were initially evaluated, and further studies extended the analysis to include 17 other products representing various formulations and Sun Protection Factors (SPF. Overall, all of the commercial brands of SPF 30 sunscreens provided sufficient protection against simulated sunlight genotoxicity. In addition, this DNA biosensor was useful for rapidly screening the biological protection properties of the various sunscreen formulations.The application of the DNA dosimeter is demonstrated as an alternative, complementary, and reliable method for the quantification of sunscreen photoprotection at the level of DNA damage.

  19. DNA dosimetry assessment for sunscreen genotoxic photoprotection.

    Science.gov (United States)

    Schuch, André Passaglia; Lago, Juliana Carvalhães; Yagura, Teiti; Menck, Carlos Frederico Martins

    2012-01-01

    Due to the increase of solar ultraviolet radiation (UV) incidence over the last few decades, the use of sunscreen has been widely adopted for skin protection. However, considering the high efficiency of sunlight-induced DNA lesions, it is critical to improve upon the current approaches that are used to evaluate protection factors. An alternative approach to evaluate the photoprotection provided by sunscreens against daily UV radiation-induced DNA damage is provided by the systematic use of a DNA dosimeter. The Sun Protection Factor for DNA (DNA-SPF) is calculated by using specific DNA repair enzymes, and it is defined as the capacity for inhibiting the generation of cyclobutane pyrimidine dimers (CPD) and oxidised DNA bases compared with unprotected control samples. Five different commercial brands of sunscreen were initially evaluated, and further studies extended the analysis to include 17 other products representing various formulations and Sun Protection Factors (SPF). Overall, all of the commercial brands of SPF 30 sunscreens provided sufficient protection against simulated sunlight genotoxicity. In addition, this DNA biosensor was useful for rapidly screening the biological protection properties of the various sunscreen formulations. The application of the DNA dosimeter is demonstrated as an alternative, complementary, and reliable method for the quantification of sunscreen photoprotection at the level of DNA damage.

  20. Spontaneous unscheduled DNA synthesis in human lymphocytes

    International Nuclear Information System (INIS)

    Forell, B.; Myers, L.S. Jr.; Norman, A.

    1979-01-01

    The rate of spontaneous unscheduled DNA synthesis in human lymphocytes was estimated from measurements of tritiated thymidine incorporation into double-stranded DNA (ds-DNA) during incubation of cells in vitro. The contribution of scheduled DNA synthesis to the observed incorporation was reduced by inhibiting replication with hydroxyurea and by separating freshly replicated single-stranded DNA (ss-DNA) from repaired ds-DNA by column chromatography. The residual contribution of scheduled DNA synthesis was estimated by observing effects on thymidine incorporation of: (a) increasing the rate of production of apurinic sites, and alternatively, (b) increasing the number of cells in S-phase. Corrections based on estimates of endogenous pool size were also made. The rate of spontaneous unscheduled DNA synthesis is estimated to be 490 +- 120 thymidine molecules incorporated per cell per hour. These results compare favorably with estimates made from rates of depurination and depyrimidination of DNA, measured in molecular systems if we assume thymidine is incorporated by a short patch mechanism which incorporates an average of four bases per lesion

  1. DNA Dosimetry Assessment for Sunscreen Genotoxic Photoprotection

    Science.gov (United States)

    Schuch, André Passaglia; Lago, Juliana Carvalhães; Yagura, Teiti; Menck, Carlos Frederico Martins

    2012-01-01

    Background Due to the increase of solar ultraviolet radiation (UV) incidence over the last few decades, the use of sunscreen has been widely adopted for skin protection. However, considering the high efficiency of sunlight-induced DNA lesions, it is critical to improve upon the current approaches that are used to evaluate protection factors. An alternative approach to evaluate the photoprotection provided by sunscreens against daily UV radiation-induced DNA damage is provided by the systematic use of a DNA dosimeter. Methodology/Principal Findings The Sun Protection Factor for DNA (DNA-SPF) is calculated by using specific DNA repair enzymes, and it is defined as the capacity for inhibiting the generation of cyclobutane pyrimidine dimers (CPD) and oxidised DNA bases compared with unprotected control samples. Five different commercial brands of sunscreen were initially evaluated, and further studies extended the analysis to include 17 other products representing various formulations and Sun Protection Factors (SPF). Overall, all of the commercial brands of SPF 30 sunscreens provided sufficient protection against simulated sunlight genotoxicity. In addition, this DNA biosensor was useful for rapidly screening the biological protection properties of the various sunscreen formulations. Conclusions/Significance The application of the DNA dosimeter is demonstrated as an alternative, complementary, and reliable method for the quantification of sunscreen photoprotection at the level of DNA damage. PMID:22768281

  2. Regulation of rDNA stability by sumoylation

    DEFF Research Database (Denmark)

    Eckert-Boulet, Nadine; Lisby, Michael

    2009-01-01

    Repair of DNA lesions by homologous recombination relies on the copying of genetic information from an intact homologous sequence. However, many eukaryotic genomes contain repetitive sequences such as the ribosomal gene locus (rDNA), which poses a risk for illegitimate recombination. Therefore, t......6 complex and sumoylation of Rad52, which directs DNA double-strand breaks in the rDNA to relocalize from within the nucleolus to the nucleoplasm before association with the recombination machinery. The relocalization before repair is important for maintaining rDNA stability. The focus...

  3. Unlocking the Sugar ‘Steric Gate’ of DNA Polymerases†

    Science.gov (United States)

    Brown, Jessica A.; Suo, Zucai

    2011-01-01

    To maintain genomic stability, ribonucleotide incorporation during DNA synthesis is controlled predominantly at the DNA polymerase level. A steric clash between the 2′-hydroxyl of an incoming ribonucleotide and a bulky active site residue, known as the ‘steric gate’, establishes an effective mechanism for most DNA polymerases to selectively insert deoxyribonucleotides. Recent kinetic, structural, and in vivo studies have illuminated novel features about ribonucleotide exclusion and the mechanistic consequences of ribonucleotide misincorporation on downstream events, such as the bypass of a ribonucleotide in a DNA template and the subsequent extension of the DNA lesion bypass product. These important findings are summarized in this review article. PMID:21226515

  4. Lesion bacterial communities in American lobsters with diet-induced shell disease.

    Science.gov (United States)

    Quinn, Robert A; Metzler, Anita; Tlusty, Michael; Smolowitz, Roxanna M; Leberg, Paul; Chistoserdov, Andrei Y

    2012-04-26

    In southern New England, USA, shell disease affects the profitability of the American lobster Homarus americanus fishery. In laboratory trials using juvenile lobsters, exclusive feeding of herring Clupea harengus induces shell disease typified initially by small melanized spots that progress into distinct lesions. Amongst a cohabitated, but segregated, cohort of 11 juvenile lobsters fed exclusively herring, bacterial communities colonizing spots and lesions were investigated by denaturing gradient gel electrophoresis of 16S rDNA amplified using 1 group-specific and 2 universal primer sets. The Bacteroidetes and Proteobacteria predominated in both spots and lesions and included members of the orders Flavobacteriales (Bacteriodetes), Rhodobacterales, Rhodospirillales and Rhizobiales (Alphaproteobacteria), Xanthomonadales (Gammaproteobacteria) and unclassified Gammaproteobacteria. Bacterial communities in spot lesions displayed more diversity than communities with larger (older) lesions, indicating that the lesion communities stabilize over time. At least 8 bacterial types persisted as lesions developed from spots. Aquimarina 'homaria', a species commonly cultured from lesions present on wild lobsters with epizootic shell disease, was found ubiquitously in spots and lesions, as was the 'Candidatus Kopriimonas aquarianus', implicating putative roles of these species in diet-induced shell disease of captive lobsters.

  5. Inhibition of DNA replication by ultraviolet light

    International Nuclear Information System (INIS)

    Edenberg, H.J.

    1976-01-01

    DNA replication in ultraviolet-irradiated HeLa cells was studied by two different techniques: measurements of the kinetics of semiconservative DNA synthesis, and DNA fiber autoradiography. In examining the kinetics of semiconservative DNA synthesis, density label was used to avoid measuring the incorporation due to repair replication. The extent of inhibition varied with time. After doses of less than 10 J/m 2 the rate was initially depressed but later showed some recovery. After higher doses, a constant, low rate of synthesis was seen for at least the initial 6 h. An analysis of these data indicated that the inhibition of DNA synthesis could be explained by replication forks halting at pyrimidine dimers. DNA fiber autoradiography was used to further characterize replication after ultraviolet irradiation. The average length of labeled segments in irradiated cells increased in the time immediately after irradiation, and then leveled off. This is the predicted pattern if DNA synthesis in each replicon continued at its previous rate until a lesion is reached, and then halted. The frequency of lesions that block synthesis is approximately the same as the frequency of pyrimidine dimers

  6. DNA repair in proteus mirabilis. Pt. 4

    International Nuclear Information System (INIS)

    Hofemeister, J.

    1977-01-01

    Post-irradiation DNA degradation in P. mirabilis rec + strains after UV irradiation is found to be more extensive in starvation buffer than in growth medium. In growth medium restriction of protein synthesis, but not DNA synthesis, largely prevents the expression of 'breakdown limitation'. By the addition of chloramphenicol during post-irradiation incubation in growth medium the expression of breakdown limitation was followed and found to occur 20 to 40 min after UV irradiation. Pre-irradiation by a low dose of UV leads after a corresponding time of post-irradiation incubation to breakdown limitation even in starvation buffer after a second UV exposure. Post-irradiation DNA degradation is presumed to be initiated at the sites of DNA lesions which arise at replication points damaged by UV. While pre-starvation restricts the efficiency of postirradiation DNA degradation by the reduction of the number of replication points active at the time of irradiation, caffeine as well as 2.4-dinitrophenol inhibit DNA degradation even in rec - cells probably by the interference with nicking or exonucleoltytic events initiated at those sites in the absence of breakdown limitation. Breakdown limitation is postulated to be due to inducible derepression of REC-functions which lead to the protection and, probably, repair of DNA lesions arising at the replication points following UV exposure. (orig.) [de

  7. Disseminated paracoccidioidomycosis diagnosis based on oral lesions

    Directory of Open Access Journals (Sweden)

    Liana Preto Webber

    2014-01-01

    Full Text Available Paracoccidioidomycosis (PCM is a deep mycosis with primary lung manifestations that may present cutaneous and oral lesions. Oral lesions mimic other infectious diseases or even squamous cell carcinoma, clinically and microscopically. Sometimes, the dentist is the first to detect the disease, because lung lesions are asymptomatic, or even misdiagnosed. An unusual case of PCM with 5 months of evolution presenting pulmonary, oral, and cutaneous lesions that was diagnosed by the dentist based on oral lesions is presented and discussed.

  8. Imaging inflammatory acne: lesion detection and tracking

    Science.gov (United States)

    Cula, Gabriela O.; Bargo, Paulo R.; Kollias, Nikiforos

    2010-02-01

    It is known that effectiveness of acne treatment increases when the lesions are detected earlier, before they could progress into mature wound-like lesions, which lead to scarring and discoloration. However, little is known about the evolution of acne from early signs until after the lesion heals. In this work we computationally characterize the evolution of inflammatory acne lesions, based on analyzing cross-polarized images that document acne-prone facial skin over time. Taking skin images over time, and being able to follow skin features in these images present serious challenges, due to change in the appearance of skin, difficulty in repositioning the subject, involuntary movement such as breathing. A computational technique for automatic detection of lesions by separating the background normal skin from the acne lesions, based on fitting Gaussian distributions to the intensity histograms, is presented. In order to track and quantify the evolution of lesions, in terms of the degree of progress or regress, we designed a study to capture facial skin images from an acne-prone young individual, followed over the course of 3 different time points. Based on the behavior of the lesions between two consecutive time points, the automatically detected lesions are classified in four categories: new lesions, resolved lesions (i.e. lesions that disappear completely), lesions that are progressing, and lesions that are regressing (i.e. lesions in the process of healing). The classification our methods achieve correlates well with visual inspection of a trained human grader.

  9. Recovery of DNA synthesis from inhibition by ultraviolet light in mammalian cells

    Energy Technology Data Exchange (ETDEWEB)

    Ventura, A M; Ortega, J M; Schumacher, R I; Meneghini, R

    1987-01-01

    In general mammalian cells recover from DNA synthesis inhibition by ultraviolet light (u.v.) before most of the pyrimidine dimers have been removed from the genome. Using metabolic inhibitors, it has been shown that (1) even the low repair rate exhibited by V79 cells is important for recovery; although most of the dimers remain in the V79 genome after recovery of DNA synthesis, either the removal of lesions from some important region of chromatin or the activity of the repair process itself is important for the recovery; (2) the recovery mechanism is induced and depends on RNA synthesis and the production of specific factors. Finally, we have observed that cells previously treated with fluorodeoxyuridine become more resistant to inhibition by u.v. Since it has been shown that this drug activates unused origins of replication in Chinese hamster cells, reducing the average replicon size, we assume that the acquired resistance has to do with the operation of a larger number of small replicons.

  10. Cystic Lesions in Autoimmune Pancreatitis

    Directory of Open Access Journals (Sweden)

    Macarena Gompertz

    2015-11-01

    Full Text Available Autoimmune pancreatitis (AIP can be chronic or recurrent, but frequently completely reversible after steroid treatment. A cystic lesion in AIP is a rare finding, and it can mimic a pancreatic cystic neoplasm. Difficulties in an exact diagnosis interfere with treatment, and surgery cannot be avoided in some cases. We report the history of a 63-year-old male presenting with jaundice and pruritus. AIP was confirmed by imaging and elevated IgG4 blood levels, and the patient completely recovered after corticosteroid therapy. One year later, he presented with a recurrent episode of AIP with elevated IgG4 levels, accompanied by the appearance of multiple intrapancreatic cystic lesions. All but 1 of these cysts disappeared after steroid treatment, but the remaining cyst in the pancreatic head was even somewhat larger 1 year later. Pancreatoduodenectomy was finally performed. Histology showed the wall of the cystic lesion to be fibrotic; the surrounding pancreatic tissue presented fibrosis, atrophy and lymphoplasmacytic infiltration by IgG4-positive cells, without malignant elements. Our case illustrates the rare possibility that cystic lesions can be part of AIP. These pseudocysts appear in the pancreatic segments involved in the autoimmune disease and can be a consequence of the local inflammation or related to ductal strictures. Steroid treatment should be initiated, after which these cysts can completely disappear with recovery from AIP. Surgical intervention may be necessary in some exceptional cases.

  11. Stereotactic lesioning for mental illness

    International Nuclear Information System (INIS)

    Kim, M.-C.; Lee, T.-K.

    2008-01-01

    The authors report stereotactically created lesioning by radiofrequency or Cyberknife radiosurgery for patients with mental illness. Since 1993, thirty-eight patients have undergone stereotactic psychosurgery for medically intractable mental illnesses. Two patients had aggressive behavior. Twenty-five patients suffered from Obsessive-Compulsive Disorder (OCD) and ten patients had depression. Another patient suffered from atypical psychosis. Bilateral amygdalotomy and subcaudate tractotomy were done for aggressive behavior. Limbic leucotomy or anterior cingulotomy was done for CCD and subcaudate tractotomy with or without cingulotomy was done for depression. In twenty-three patients, the lesions were made by a radiofrequency (RF) lesion generator. In fifteen cases, the lesions were made with Cyberknife Radiosurgery (CKRS). The Overt Aggression Scale (OAS) declined from 8 to 2 with clinical improvement during follow up period. With long-term follow up (meaning 57 months) in 25 OCDs, the mean Yale Brown Obsessive Compulsive Score (YBOCS) declined from 34 to 13 (n = 25). The Hamilton Depression scale (HAMD) for ten patients with depression declined from 38.5 to 10.5 (n = 10). There was no operative mortality and no significant morbidity except one case with transient urinary incontinence. Authors suggest that stereotactic psychosurgery by RF and CKRS could be a safe and effective means of treating some medically intractable mental illnesses. (author)

  12. Secondary syphilis lesions resembling pityriasis

    International Nuclear Information System (INIS)

    Dar, N.R.; Ali, L.; Nawaz, M.A.

    2007-01-01

    This case report describes a male patient who presented with generalized, centrally-ulcerated papules with crusts and hypopigmented macules. Initially, differential diagnostic considerations included pityriasis lichenoides but the serology for syphilis was positive and there was a rapid response to penicillin with clearing of the lesions at the end of three weeks treatment. (author)

  13. DNA synthesis in ataxia telangiectasia

    OpenAIRE

    Jaspers, Nicolaas

    1985-01-01

    textabstractAfter the discovery that cultured cells from AT patients are hypersensitive to ionizing radiation the suggestion was made that AT-could be the 1 X-ray-analogue 1 of xeroderma pigmentosum. The latter syndrome (XP) is characterized by hypersensitivity to short-wave UV-radiation, caused by a reduced ability to properly remove UV-induced DNA damage. The evidence for a DNA repair defect in AT cells is not as strong as in the case of XP (see section 2.2.5 of this thesis). Different XP p...

  14. Radiation damage to DNA in DNA-protein complexes.

    Science.gov (United States)

    Spotheim-Maurizot, M; Davídková, M

    2011-06-03

    The most aggressive product of water radiolysis, the hydroxyl (OH) radical, is responsible for the indirect effect of ionizing radiations on DNA in solution and aerobic conditions. According to radiolytic footprinting experiments, the resulting strand breaks and base modifications are inhomogeneously distributed along the DNA molecule irradiated free or bound to ligands (polyamines, thiols, proteins). A Monte-Carlo based model of simulation of the reaction of OH radicals with the macromolecules, called RADACK, allows calculating the relative probability of damage of each nucleotide of DNA irradiated alone or in complexes with proteins. RADACK calculations require the knowledge of the three dimensional structure of DNA and its complexes (determined by X-ray crystallography, NMR spectroscopy or molecular modeling). The confrontation of the calculated values with the results of the radiolytic footprinting experiments together with molecular modeling calculations show that: (1) the extent and location of the lesions are strongly dependent on the structure of DNA, which in turns is modulated by the base sequence and by the binding of proteins and (2) the regions in contact with the protein can be protected against the attack by the hydroxyl radicals via masking of the binding site and by scavenging of the radicals. 2011 Elsevier B.V. All rights reserved.

  15. A non-destructive DNA sampling technique for herbarium specimens.

    Science.gov (United States)

    Shepherd, Lara D

    2017-01-01

    Herbarium specimens are an important source of DNA for plant research but current sampling methods require the removal of material for DNA extraction. This is undesirable for irreplaceable specimens such as rare species or type material. Here I present the first non-destructive sampling method for extracting DNA from herbarium specimens. DNA was successfully retrieved from robust leaves and/or stems of herbarium specimens up to 73 years old.

  16. Dam removal: Listening in

    Science.gov (United States)

    Foley, M. M.; Bellmore, J. R.; O'Connor, J. E.; Duda, J. J.; East, A. E.; Grant, G. E.; Anderson, C. W.; Bountry, J. A.; Collins, M. J.; Connolly, P. J.; Craig, L. S.; Evans, J. E.; Greene, S. L.; Magilligan, F. J.; Magirl, C. S.; Major, J. J.; Pess, G. R.; Randle, T. J.; Shafroth, P. B.; Torgersen, C. E.; Tullos, D.; Wilcox, A. C.

    2017-07-01

    Dam removal is widely used as an approach for river restoration in the United States. The increase in dam removals—particularly large dams—and associated dam-removal studies over the last few decades motivated a working group at the USGS John Wesley Powell Center for Analysis and Synthesis to review and synthesize available studies of dam removals and their findings. Based on dam removals thus far, some general conclusions have emerged: (1) physical responses are typically fast, with the rate of sediment erosion largely dependent on sediment characteristics and dam-removal strategy; (2) ecological responses to dam removal differ among the affected upstream, downstream, and reservoir reaches; (3) dam removal tends to quickly reestablish connectivity, restoring the movement of material and organisms between upstream and downstream river reaches; (4) geographic context, river history, and land use significantly influence river restoration trajectories and recovery potential because they control broader physical and ecological processes and conditions; and (5) quantitative modeling capability is improving, particularly for physical and broad-scale ecological effects, and gives managers information needed to understand and predict long-term effects of dam removal on riverine ecosystems. Although these studies collectively enhance our understanding of how riverine ecosystems respond to dam removal, knowledge gaps remain because most studies have been short (< 5 years) and do not adequately represent the diversity of dam types, watershed conditions, and dam-removal methods in the U.S.

  17. The Seed Repair Response during Germination: Disclosing Correlations between DNA Repair, Antioxidant Response, and Chromatin Remodeling in Medicago truncatula

    Directory of Open Access Journals (Sweden)

    Andrea Pagano

    2017-11-01

    Full Text Available This work provides novel insights into the effects caused by the histone deacetylase inhibitor trichostatin A (TSA during Medicago truncatula seed germination, with emphasis on the seed repair response. Seeds treated with H2O and TSA (10 and 20 μM were collected during imbibition (8 h and at the radicle protrusion phase. Biometric data showed delayed germination and impaired seedling growth in TSA-treated samples. Comet assay, performed on radicles at the protrusion phase and 4-days old M. truncatula seedlings, revealed accumulation of DNA strand breaks upon exposure to TSA. Activation of DNA repair toward TSA-mediated genotoxic damage was evidenced by the up-regulation of MtOGG1(8-OXOGUANINE GLYCOSYLASE/LYASE gene involved in the removal of oxidative DNA lesions, MtLIGIV(LIGASE IV gene, a key determinant of seed quality, required for the rejoining of DNA double strand breaks and TDP(TYROSYL-DNA PHOSPHODIESTERASE genes encoding the multipurpose DNA repair enzymes tyrosyl-DNA phosphodiesterases. Since radical scavenging can prevent DNA damage, the specific antioxidant activity (SAA was measured by DPPH (1,1-diphenyl-2-picrylhydrazyl and Folin-Ciocalteu reagent assays. Fluctuations of SAA were observed in TSA-treated seeds/seedlings concomitant with the up-regulation of antioxidant genes MtSOD(SUPEROXIDE DISMUTASE, MtAPX(ASCORBATE PEROXIDASE and MtMT2(TYPE 2 METALLOTHIONEIN. Chromatin remodeling, required to facilitate the access of DNA repair enzymes at the damaged sites, is also part of the multifaceted seed repair response. To address this aspect, still poorly explored in plants, the MtTRRAP(TRANSFORMATION/TRANSACTIVATION DOMAIN-ASSOCIATED PROTEIN gene was analyzed. TRRAP is a transcriptional adaptor, so far characterized only in human cells where it is needed for the recruitment of histone acetyltransferase complexes to chromatin during DNA repair. The MtTRRAP gene and the predicted interacting partners MtHAM2 (HISTONE ACETYLTRANSFERASE OF

  18. Immediate implants in extraction sockets with periapical lesions: an illustrated review

    Directory of Open Access Journals (Sweden)

    Arthur B. Novaes Jr.

    2013-10-01

    Full Text Available Aim Immediate implantation has gained great attention since first proposed. Immediate implants in replacement of teeth with periapical lesion is, to date, an issue of discussion. The aim of this study is to perform an illustrated literature review of immediate implants in sockets exhibiting previous periapical lesions.Materials and methods A search on medline/EMBASE database was done for the literature review which is presented together with two case reports illustrating the state of the art of immediate implants on sockets with periapical lesions. Both cases are presented in areas with great aesthetic demands and a periapical lesion of considerable size. The two cases were conducted following strict granulation tissue removal and careful rinsing and pre-operative antibiotics, followed by good primary stability of the dental implant.Results and conclusion Both cases represented successes in aesthetics and function, describing a successful protocol for immediate implant installation in areas exhibiting periapical lesions.

  19. Studies on DNA Damage Response in Sulfolobus islandicus

    DEFF Research Database (Denmark)

    Han, Wenyuan

    ) and methyl methanesulfonate (MMS), and hydroxyurea (HU) that may not introduce DNA lesions directly. Comparison of the effects of the three drugs on S. islandicus cells showed that NQO and MMS led to DNA-less cell formation, while HU did not. In addition, the DNA-less cells were featured with increased side...

  20. Imitation of radiation-induced damages to DNA with a radionuclide incorporated into polynucleotides

    International Nuclear Information System (INIS)

    Korolev, V.G.

    1984-01-01

    Because of a great variety and different reparability of radiation-induced DNA lesions it is difficult to evaluate the radiobiologacal significance of certain individual alterations. It is suggested that the radionuclides incorporated anto DNA can be used to imitate different types of radiation damages to DNA. Both qualitative and quantitative aspects of the problem are discussed

  1. Useful surgical techniques for facial nerve preservation in tumorous intra-temporal lesions.

    Science.gov (United States)

    Kim, Jin; Moon, In Seok; Lee, Jong Dae; Shim, Dae Bo; Lee, Won-Sang

    2010-02-01

    The management of the facial nerve in tumorous temporal lesions is particularly challenging due to its complex anatomic location and potential postoperative complications, including permanent facial paralysis. The most important concern regarding surgical treatment of a tumorous temporal lesion is the inevitable facial paralysis caused by nerve injury during the tumor removal, especially in patients with minimal to no preoperative facial nerve dysfunction. We describe successful four cases in which various surgical techniques were developed for the preservation of the facial nerve in treatment of intratemporal tumorous lesions. Copyright (c) 2009 Elsevier Ireland Ltd. All rights reserved.

  2. Biological effects of DNA repair, including mutagenesis. Progress report, August 15, 1982-August 1, 1983. COO-3571-23

    International Nuclear Information System (INIS)

    Hutchinson, F.

    1983-01-01

    The research supported by this contract for the period covered by this report has concerned mechanisms in mutagenesis. Specifically, the work has been aimed at determining the lesions in DNA formed by particular mutagenic agents which lead to mutations, and to characterization of the pathways by which these lesions lead to changes in the sequence of bases in the genomic DNA

  3. Involvement of DNA polymerase beta in repair of ionizing radiation damage as measured by in vitro plasmid assays.

    NARCIS (Netherlands)

    Vens, C.; Hofland, I.; Begg, A.C.

    2007-01-01

    Characteristic of damage introduced in DNA by ionizing radiation is the induction of a wide range of lesions. Single-strand breaks (SSBs) and base damages outnumber double-strand breaks (DSBs). If unrepaired, these lesions can lead to DSBs and increased mutagenesis. XRCC1 and DNA polymerase beta

  4. Petrous apex lesions in the pediatric population

    Energy Technology Data Exchange (ETDEWEB)

    Radhakrishnan, Rupa [University of Cincinnati College of Medicine, Department of Radiology, Cincinnati, OH (United States); Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States); Son, Hwa Jung [University of Cincinnati College of Medicine, Department of Otolaryngology-Head and Neck Surgery, Cincinnati, OH (United States); Koch, Bernadette L. [Cincinnati Children' s Hospital Medical Center, Department of Radiology, Cincinnati, OH (United States)

    2014-03-15

    A variety of abnormal imaging findings of the petrous apex are encountered in children. Many petrous apex lesions are identified incidentally while images of the brain or head and neck are being obtained for indications unrelated to the temporal bone. Differential considerations of petrous apex lesions in children include ''leave me alone'' lesions, infectious or inflammatory lesions, fibro-osseous lesions, neoplasms and neoplasm-like lesions, as well as a few rare miscellaneous conditions. Some lesions are similar to those encountered in adults, and some are unique to children. Langerhans cell histiocytosis (LCH) and primary and metastatic pediatric malignancies such as neuroblastoma, rhabomyosarcoma and Ewing sarcoma are more likely to be encountered in children. Lesions such as petrous apex cholesterol granuloma, cholesteatoma and chondrosarcoma are more common in adults and are rarely a diagnostic consideration in children. We present a comprehensive pictorial review of CT and MRI appearances of pediatric petrous apex lesions. (orig.)

  5. Hair removal in adolescence

    Directory of Open Access Journals (Sweden)

    Sandra Pereira

    2015-06-01

    Full Text Available Introduction: Due to hormonal stimulation during puberty, changes occur in hair type and distribution. In both sexes, body and facial unwanted hair may have a negative psychological impact on the teenager. There are several available methods of hair removal, but the choice of the most suitable one for each individual can raise doubts. Objective: To review the main methods of hair removal and clarify their indications, advantages and disadvantages. Development: There are several removal methods currently available. Shaving and depilation with chemicals products are temporary methods, that need frequent repetition, because hair removal is next to the cutaneous surface. The epilating methods in which there is full hair extraction include: epilation with wax, thread, tweezers, epilating machines, laser, intense pulsed light, and electrolysis. Conclusions: The age of beginning hair removal and the method choice must be individualized and take into consideration the skin and hair type, location, dermatological and endocrine problems, removal frequency, cost and personal preferences.

  6. Imaging review of lipomatous musculoskeletal lesions

    Directory of Open Access Journals (Sweden)

    Burt Ashley M.

    2017-01-01

    Full Text Available Lipomatous lesions are common musculoskeletal lesions that can arise within the soft tissues, bone, neurovascular structures, and synovium. The majority of these lesions are benign, and many of the benign lesions can be diagnosed by radiologic evaluation. However, radiologic differences between benign and malignant lipomatous lesions may be subtle and pathologic correlation is often needed. The use of sonography, computed tomography (CT, and magnetic resonance imaging (MRI is useful not only in portraying fat within the lesion, but also for evaluating the presence and extent of soft tissue components. Lipomas make up most soft tissue lipomatous lesions, but careful evaluation must be performed to distinguish these lesions from a low-grade liposarcoma. In addition to the imaging appearance, the location of the lesion and the patient demographics can be utilized to help diagnose other soft tissue lipomatous lesions, such as elastofibroma dorsi, angiolipoma, lipoblastoma, and hibernoma. Osseous lipomatous lesions such as a parosteal lipoma and intraosseous lipoma occur less commonly as their soft tissue counterpart, but are also benign. Neurovascular and synovial lipomatous lesions are much rarer lesions but demonstrate more classic radiologic findings, particularly on MRI. A review of the clinical, radiologic, and pathologic characteristics of these lesions is presented.

  7. Release of 3-methyladenine from linker and core DNA of chromatin by a purified DNA glycosylase

    International Nuclear Information System (INIS)

    Heller, E.P.; Goldthwait, D.A.

    1983-01-01

    Oligonucleosomes were isolated from [ 14 C]thymidine-labeled HeLa cells by digestion of the nuclei with micrococcal nuclease and were then alkylated with [ 3 H]methylnitrosourea. Nucleosome core particles were also prepared by further digestion of the oligonucleosomes. The distribution of 3 H-labeled methyl groups in the linker versus the core DNA was established by a determination of 3 H: 14 C ratios in oligonucleosome and core DNA. The ratios in the core DNA of 145 and 165 base pair DNA fragments were 5.2 and 5.4, respectively, while the ratio in the oligonucleosomal DNA was 8.2. Assuming an equal mixture (as determined) of 145 and 165 base pair fragments of DNA in the 185 base pair repeat, the relative concentration of 3