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Sample records for repair damaged tissue

  1. Regenerative repair of damaged meniscus with autologous adipose tissue-derived stem cells.

    Science.gov (United States)

    Pak, Jaewoo; Lee, Jung Hun; Lee, Sang Hee

    2014-01-01

    Mesenchymal stem cells (MSCs) are defined as pluripotent cells found in numerous human tissues, including bone marrow and adipose tissue. Such MSCs, isolated from bone marrow and adipose tissue, have been shown to differentiate into bone and cartilage, along with other types of tissues. Therefore, MSCs represent a promising new therapy in regenerative medicine. The initial treatment of meniscus tear of the knee is managed conservatively with nonsteroidal anti-inflammatory drugs and physical therapy. When such conservative treatment fails, an arthroscopic resection of the meniscus is necessary. However, the major drawback of the meniscectomy is an early onset of osteoarthritis. Therefore, an effective and noninvasive treatment for patients with continuous knee pain due to damaged meniscus has been sought. Here, we present a review, highlighting the possible regenerative mechanisms of damaged meniscus with MSCs (especially adipose tissue-derived stem cells (ASCs)), along with a case of successful repair of torn meniscus with significant reduction of knee pain by percutaneous injection of autologous ASCs into an adult human knee.

  2. The alterations in the extracellular matrix composition guide the repair of damaged liver tissue.

    Science.gov (United States)

    Klaas, Mariliis; Kangur, Triin; Viil, Janeli; Mäemets-Allas, Kristina; Minajeva, Ave; Vadi, Krista; Antsov, Mikk; Lapidus, Natalia; Järvekülg, Martin; Jaks, Viljar

    2016-06-06

    While the cellular mechanisms of liver regeneration have been thoroughly studied, the role of extracellular matrix (ECM) in liver regeneration is still poorly understood. We utilized a proteomics-based approach to identify the shifts in ECM composition after CCl4 or DDC treatment and studied their effect on the proliferation of liver cells by combining biophysical and cell culture methods. We identified notable alterations in the ECM structural components (eg collagens I, IV, V, fibronectin, elastin) as well as in non-structural proteins (eg olfactomedin-4, thrombospondin-4, armadillo repeat-containing x-linked protein 2 (Armcx2)). Comparable alterations in ECM composition were seen in damaged human livers. The increase in collagen content and decrease in elastic fibers resulted in rearrangement and increased stiffness of damaged liver ECM. Interestingly, the alterations in ECM components were nonhomogenous and differed between periportal and pericentral areas and thus our experiments demonstrated the differential ability of selected ECM components to regulate the proliferation of hepatocytes and biliary cells. We define for the first time the alterations in the ECM composition of livers recovering from damage and present functional evidence for a coordinated ECM remodelling that ensures an efficient restoration of liver tissue.

  3. Damage, DNA Repair, Aging, and Neurodegeneration

    Science.gov (United States)

    Maynard, Scott; Fang, Evandro Fei; Scheibye-Knudsen, Morten; Croteau, Deborah L.; Bohr, Vilhelm A.

    2017-01-01

    Aging in mammals is accompanied by a progressive atrophy of tissues and organs, and stochastic damage accumulation to the macromolecules DNA, RNA, proteins, and lipids. The sequence of the human genome represents our genetic blueprint, and accumulating evidence suggests that loss of genomic maintenance may causally contribute to aging. Distinct evidence for a role of imperfect DNA repair in aging is that several premature aging syndromes have underlying genetic DNA repair defects. Accumulation of DNA damage may be particularly prevalent in the central nervous system owing to the low DNA repair capacity in postmitotic brain tissue. It is generally believed that the cumulative effects of the deleterious changes that occur in aging, mostly after the reproductive phase, contribute to species-specific rates of aging. In addition to nuclear DNA damage contributions to aging, there is also abundant evidence for a causative link between mitochondrial DNA damage and the major phenotypes associated with aging. Understanding the mechanistic basis for the association of DNA damage and DNA repair with aging and age-related diseases, such as neurodegeneration, would give insight into contravening age-related diseases and promoting a healthy life span. PMID:26385091

  4. Bypassing damaged nervous tissue

    CERN Document Server

    Shneider, M N

    2016-01-01

    We show the principal ability of bypassing damaged demyelinated portions of nervous tissue, thereby restoring its normal function for the passage of action potentials. We carry out a theoretical analysis on the basis of the synchronization mechanism of action potential propagation along a bundle of neurons, proposed recently in [1]. And we discuss the feasibility of implement a bypass to restore damaged nervous tissue and creating an artificial neuron network.

  5. Chromatin structure and DNA damage repair

    Directory of Open Access Journals (Sweden)

    Dinant Christoffel

    2008-11-01

    Full Text Available Abstract The integrity of the genome is continuously challenged by both endogenous and exogenous DNA damaging agents. These damaging agents can induce a wide variety of lesions in the DNA, such as double strand breaks, single strand breaks, oxidative lesions and pyrimidine dimers. The cell has evolved intricate DNA damage response mechanisms to counteract the genotoxic effects of these lesions. The two main features of the DNA damage response mechanisms are cell-cycle checkpoint activation and, at the heart of the response, DNA repair. For both damage signalling and repair, chromatin remodelling is most likely a prerequisite. Here, we discuss current knowledge on chromatin remodelling with respect to the cellular response to DNA damage, with emphasis on the response to lesions resolved by nucleotide excision repair. We will discuss the role of histone modifications as well as their displacement or exchange in nucleotide excision repair and make a comparison with their requirement in transcription and double strand break repair.

  6. Repairable-conditionally repairable damage model based on dual Poisson processes.

    Science.gov (United States)

    Lind, B K; Persson, L M; Edgren, M R; Hedlöf, I; Brahme, A

    2003-09-01

    The advent of intensity-modulated radiation therapy makes it increasingly important to model the response accurately when large volumes of normal tissues are irradiated by controlled graded dose distributions aimed at maximizing tumor cure and minimizing normal tissue toxicity. The cell survival model proposed here is very useful and flexible for accurate description of the response of healthy tissues as well as tumors in classical and truly radiobiologically optimized radiation therapy. The repairable-conditionally repairable (RCR) model distinguishes between two different types of damage, namely the potentially repairable, which may also be lethal, i.e. if unrepaired or misrepaired, and the conditionally repairable, which may be repaired or may lead to apoptosis if it has not been repaired correctly. When potentially repairable damage is being repaired, for example by nonhomologous end joining, conditionally repairable damage may require in addition a high-fidelity correction by homologous repair. The induction of both types of damage is assumed to be described by Poisson statistics. The resultant cell survival expression has the unique ability to fit most experimental data well at low doses (the initial hypersensitive range), intermediate doses (on the shoulder of the survival curve), and high doses (on the quasi-exponential region of the survival curve). The complete Poisson expression can be approximated well by a simple bi-exponential cell survival expression, S(D) = e(-aD) + bDe(-cD), where the first term describes the survival of undamaged cells and the last term represents survival after complete repair of sublethal damage. The bi-exponential expression makes it easy to derive D(0), D(q), n and alpha, beta values to facilitate comparison with classical cell survival models.

  7. Treatment with metallothionein prevents demyelination and axonal damage and increases oligodendrocyte precursors and tissue repair during experimental autoimmune encephalomyelitis

    DEFF Research Database (Denmark)

    Penkowa, Milena; Hidalgo, Juan

    2003-01-01

    )beta, neurotrophin-3 (NT-3), NT-4/5, and nerve growth factor (NGF). These beneficial effects of Zn-MT-II treatment could not be attributable to its zinc content per se. The present results support further the use of Zn-MT-II as a safe and successful therapy for multiple sclerosis....... for the first time that Zn-MT-II treatment during EAE significantly prevents demyelination and axonal damage and transection, and stimulates oligodendroglial regeneration from precursor cells, as well as the expression of the growth factors basic fibroblast growth factor (bFGF), transforming growth factor (TGF...

  8. 49 CFR 1242.42 - Administration, repair and maintenance, machinery repair, equipment damaged, dismantling retired...

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Administration, repair and maintenance, machinery repair, equipment damaged, dismantling retired property, fringe benefits, other casualties and insurance... maintenance, machinery repair, equipment damaged, dismantling retired property, fringe benefits,...

  9. Civil liability for ecologic damage and repairing

    OpenAIRE

    Basílio, Patrícia Droeber; Faculdades de Vitória, Espírito Santo, Brasil

    2009-01-01

    This article analyses how civil liability takes position regarding situations connected to damages caused to the environment, defined ways in our legislation reprimanding damages caused and existent ways of prevention and repairing. The text contemplates how law disciplines such issue, looking for efficient and effective solutions and also checking evolution and modification from law which are relevant to the environment, the environmental law, whereas we observe it is a serious issue that ha...

  10. Research Progress of Tissue-engineered Cartilage to Repair Articular Cartilage Damage in Western and Chinese Medicine%组织工程软骨修复关节软骨损伤中西医研究进展

    Institute of Scientific and Technical Information of China (English)

    陈强; 蔡建平; 张爱国

    2012-01-01

    Articular cartilage damage and repair have been the thorny issue of orthopedic basic research and clinical treatment. Articular cartilage damage is becoming increasingly prominent, and has become a serious challenge faced by the multi-disciplinary trauma surgery, orthopedics, elderly subjects, as well as sports medicine. In this paper, the articular cartilage damage repair status, the tissue-engineered cartilage and Chinese medicine were made an overview of research on tissue engineered cartilage.%关节软骨的损伤和修复,一直以来是骨科基础研究与临床治疗的棘手问题.关节软骨损伤问题日益突出,俨然成为创伤外科、骨科、老年学科以及运动医学等多学科面临的严峻挑战.文章就关节软骨损伤修复现状、组织工程软骨技术及中药在组织工程软骨中的研究三方面做一概述.

  11. Differential expression of tissue repair genes in the pathogenesis of chronic obstructive pulmonary disease

    National Research Council Canada - National Science Library

    Gosselink, John V; Hayashi, Shizu; Elliott, W Mark; Xing, Li; Chan, Becky; Yang, Luojia; Wright, Claire; Sin, Don; Paré, Peter D; Pierce, John A; Pierce, Richard A; Patterson, Alex; Cooper, Joel; Hogg, James C

    2010-01-01

    .... The expression of 54 genes associated with repair of repetitively damaged tissue was measured in 136 paired samples of small bronchioles and surrounding lung tissue separated by laser capture microdissection...

  12. Nuclear survivin and its relationship to DNA damage repair genes in non-small cell lung cancer investigated using tissue array.

    Directory of Open Access Journals (Sweden)

    Songliu Hu

    Full Text Available PURPOSE: To investigate the predictive role and association of nuclear survivin and the DNA double-strand breaks repair genes in non-small cell lung cancer (NSCLC: DNA-dependent protein kinase catalytic subunit (DNA-PKcs, Ku heterodimeric regulatory complex 70-KD subunit (Ku70 and ataxia-telangiectasia mutated (ATM. METHODS: The protein expression of nuclear survivin, DNA-PKcs, Ku70 and ATM were investigated using immunohistochemistry in tumors from 256 patients with surgically resected NSCLC. Furthermore, we analyzed the correlation between the expression of nuclear survivin, DNA-PKcs, Ku70 and ATM. Univariate and multivariate analyses were performed to determine the prognostic factors that inuenced the overall survival and disease-free survival of NSCLC. RESULTS: The expression of nuclear survivin, DNA-PKcs, Ku70 and ATM was significantly higher in tumor tissues than in normal tissues. By dichotomizing the specimens as expressing low or high levels of nuclear survivin, nuclear survivin correlated significantly with the pathologic stage (P = 0.009 and lymph node status (P = 0.004. The nuclear survivin levels were an independent prognostic factor for both the overall survival and the disease-free survival in univariate and multivariate analyses. Patients with low Ku70 and DNA-PKcs expression had a greater benefit from radiotherapy than patients with high expression of Ku70 (P = 0.012 and DNA-PKcs (P = 0.02. Nuclear survivin expression positively correlated with DNA-PKcs (P<0.001 and Ku70 expression (P<0.001. CONCLUSIONS: Nuclear survivin may be a prognostic factor for overall survival in patients with resected stage I-IIIA NSCLC. DNA-PKcs and Ku70 could predict the effect of radiotherapy in patients with NSCLC. Nuclear survivin may also stimulates DNA double-strand breaks repair by its interaction with DNA-PKcs and Ku70.

  13. Macrophages in Tissue Repair, Regeneration, and Fibrosis.

    Science.gov (United States)

    Wynn, Thomas A; Vannella, Kevin M

    2016-03-15

    Inflammatory monocytes and tissue-resident macrophages are key regulators of tissue repair, regeneration, and fibrosis. After tissue injury, monocytes and macrophages undergo marked phenotypic and functional changes to play critical roles during the initiation, maintenance, and resolution phases of tissue repair. Disturbances in macrophage function can lead to aberrant repair, such that uncontrolled production of inflammatory mediators and growth factors, deficient generation of anti-inflammatory macrophages, or failed communication between macrophages and epithelial cells, endothelial cells, fibroblasts, and stem or tissue progenitor cells all contribute to a state of persistent injury, and this could lead to the development of pathological fibrosis. In this review, we discuss the mechanisms that instruct macrophages to adopt pro-inflammatory, pro-wound-healing, pro-fibrotic, anti-inflammatory, anti-fibrotic, pro-resolving, and tissue-regenerating phenotypes after injury, and we highlight how some of these mechanisms and macrophage activation states could be exploited therapeutically.

  14. Regulation of tissue repair and regeneration by electric fields

    Institute of Scientific and Technical Information of China (English)

    WANG En-tong; ZHAO Min

    2010-01-01

    Endogenous electric fields(Efs)have been detected at wounds and damaged tissues.The potential roles of Efs in tissue repair and regeneration have been an intriguing topic for centuries.Recent researches have provided significant insights into how naturally occurring Efs may participate in the control of tissue repair and regeneration.Applied Efs equivalent to the size of fields measured in vivo direct cell migration,cell proliferation and nerve sprouting at wounds.More remarkably,physiological Efs are a guidance cue that directs cell migration which overrides other well accepted directional signals including initial injury stimulation,wound void,contact inhibition release,population pressure and chemotaxis.Efs activate many intracellular signaling pathways in a directional manner.Modulation of endogenous wound Efs affects epithelial cell migration,cell proliferation,and nerve growth at cornea wounds in vivo.Electric stimulation is being tested clinically for the treatments of bone fracture,wound healing and spinal cord injury.Efs thus may represent a novel type of signaling paradigm in tissue repair and regeneration.Combination of the electric stimulation and other well understood biochemical regulatory mechanisms may offer powerful and effective therapies for tissue repair and regeneration.This review introduces experimental evidence for the existence of endogenous Efs and discusses their roles in tissue repair and regeneration.

  15. Regulation of tissue repair and regeneration by electric fields.

    Science.gov (United States)

    Wang, En-tong; Zhao, Min

    2010-02-01

    Endogenous electric fields (EFs) have been detected at wounds and damaged tissues. The potential roles of EFs in tissue repair and regeneration have been an intriguing topic for centuries. Recent researches have provided significant insights into how naturally occurring EFs may participate in the control of tissue repair and regeneration. Applied EFs equivalent to the size of fields measured in vivo direct cell migration, cell proliferation and nerve sprouting at wounds. More remarkably, physiological EFs are a guidance cue that directs cell migration which overrides other well accepted directional signals including initial injury stimulation, wound void, contact inhibition release, population pressure and chemotaxis. EFs activate many intracellular signaling pathways in a directional manner. Modulation of endogenous wound EFs affects epithelial cell migration, cell proliferation, and nerve growth at cornea wounds in vivo. Electric stimulation is being tested clinically for the treatments of bone fracture, wound healing and spinal cord injury. EFs thus may represent a novel type of signaling paradigm in tissue repair and regeneration. Combination of the electric stimulation and other well understood biochemical regulatory mechanisms may offer powerful and effective therapies for tissue repair and regeneration. This review introduces experimental evidence for the existence of endogenous EFs and discusses their roles in tissue repair and regeneration.

  16. Characterization of oxidative guanine damage and repair in mammalian telomeres.

    Directory of Open Access Journals (Sweden)

    Zhilong Wang

    2010-05-01

    Full Text Available 8-oxo-7,8-dihydroguanine (8-oxoG and 2,6-diamino-4-hydroxy-5-formamidopyrimidine (FapyG are among the most common oxidative DNA lesions and are substrates for 8-oxoguanine DNA glycosylase (OGG1-initiated DNA base excision repair (BER. Mammalian telomeres consist of triple guanine repeats and are subject to oxidative guanine damage. Here, we investigated the impact of oxidative guanine damage and its repair by OGG1 on telomere integrity in mice. The mouse cells were analyzed for telomere integrity by telomere quantitative fluorescence in situ hybridization (telomere-FISH, by chromosome orientation-FISH (CO-FISH, and by indirect immunofluorescence in combination with telomere-FISH and for oxidative base lesions by Fpg-incision/Southern blot assay. In comparison to the wild type, telomere lengthening was observed in Ogg1 null (Ogg1(-/- mouse tissues and primary embryonic fibroblasts (MEFs cultivated in hypoxia condition (3% oxygen, whereas telomere shortening was detected in Ogg1(-/- mouse hematopoietic cells and primary MEFs cultivated in normoxia condition (20% oxygen or in the presence of an oxidant. In addition, telomere length abnormalities were accompanied by altered telomere sister chromatid exchanges, increased telomere single- and double-strand breaks, and preferential telomere lagging- or G-strand losses in Ogg1(-/- mouse cells. Oxidative guanine lesions were increased in telomeres in Ogg1(-/- mice with aging and primary MEFs cultivated in 20% oxygen. Furthermore, oxidative guanine lesions persisted at high level in Ogg1(-/- MEFs after acute exposure to hydrogen peroxide, while they rapidly returned to basal level in wild-type MEFs. These findings indicate that oxidative guanine damage can arise in telomeres where it affects length homeostasis, recombination, DNA replication, and DNA breakage repair. Our studies demonstrate that BER pathway is required in repairing oxidative guanine damage in telomeres and maintaining telomere integrity

  17. Dog sciatic nerve gap repaired by artificial tissue nerve graft

    Institute of Scientific and Technical Information of China (English)

    GU Xiaosong; ZHANG Peiyun; WANG Xiaodong; DING Fei; PENG Luping; CHENG Hongbing

    2003-01-01

    The feasibility of repairing dog sciatic nerve damage by using a biodegradable artificial tissue nerve graft enriched with neuroregenerating factors is investigated. The artificial nerve graft was implanted to a 30 mm gap of the sciatic nerve damage in 7 dogs. The dogs with the same nerve damage that were repaired by interposition of the autologous nerve or were given no treatment served as control group 1 or 2, respectively. The observations include gross and morphological observations, immune reaction, electrophysiological examination, fluorescence tracing of the neuron formation and the number of the neurons at the experimental sites, etc. Results showed that 6 months after the implantation of the graft, the regenerated nerve repaired the damage of the sciatic nerve without occurrence of rejection and obvious inflammatory reaction in all 7 dogs, and the function of the sciatic nerve recovered with the nerve conduction velocity of (23.91±11.35)m/s. The regenerated neurons and the forming of axon could be observed under an electron microscope. This proves that artificial tissue nerve graft transplantation can bridge the damaged nerve ends and promote the nerve regeneration.

  18. A progression of damage repair capability in self-repairing composites

    Science.gov (United States)

    Dry, Carolyn

    2014-04-01

    This paper covers several projects in which the author sought to determine the extent of damage against which self repair would be effective. So far no limits have been reached beyond those of the fiber/matrix itself. Starting with repair of barely visible damage in airplane wings consisting of graphite fiber/resin matrix composites progression was next to self repair of ballistic damage to vinyl ester walls and epoxy resin walls and finally blast damage self repair of walls and then blast and ballistic damage were combined.

  19. Quantification of thermal damage in skin tissue

    Institute of Scientific and Technical Information of China (English)

    Xu Feng; Wen Ting; Lu Tianjian; Seffen Keith

    2008-01-01

    Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great problem for burn patients. Thus, it is of great importance to quantify the thermal damage in skin tissue. In this paper, the available models and experimental methods for quantification of thermal damage in skin tissue are discussed.

  20. Interplay between mechanisms of damage and repair in multiple sclerosis.

    Science.gov (United States)

    Stadelmann, Christine; Brück, Wolfgang

    2008-03-01

    The neuropathology of multiple sclerosis is characterised by focal damage to white matter. However, tissue damage is also present in the cortical grey matter, with a particularly high prevalence of cortical demyelination being observed in secondary progressive and primary progressive forms of the disease. The presence of meningeal B-cell follicle-like structures, which frequently appear during the secondary progressive phase of disease, may be involved in the formation of these subpial cortical lesions. Diffuse white matter inflammation accompanied by axonal damage can also be observed in normal appearing white matter and, again, this is more prominent in chronic progressive forms of multiple sclerosis than in acute stages of disease. Axonal damage is a particularly important component of the pathology of multiple sclerosis and appears to be a critical determinant of clinical outcome. Axons appear to become vulnerable to injury as a result of loss of their myelin sheaths. Remyelination represents an important mechanism of tissue repair in multiple sclerosis and already occurs at an early stage of lesion development and in both white and grey matter lesions. The extent of remyelination appears to be greater in cortical lesions and in lesions further from the ventricles. There is important heterogeneity between patients in terms of the extent of remyelination, which may reflect underlying differences in pathogenetic mechanisms between patients.

  1. Strategies for cell engineering in tissue repair.

    Science.gov (United States)

    Brown, R A; Smith, K D; Angus McGrouther, D

    1997-01-01

    Cellular and tissue engineering are new areas of research, currently attracting considerable interest because of the remarkable potential they have for clinical application. Some claims have indeed been dramatic, including the possibility of growing complete, artificial organs, such as the liver. However, amid such long-term aspirations there is the very real possibility that small tissues (artificial grafts) may be fabricated in the near future for use in reconstructive surgery. Logically, we should focus on how it is possible to produce modest, engineered tissues for tissue repair. It is evident that strategies to date either depend on innate information within implanted cells, to reform the target tissue or aim to provide appropriate environmental cues or guidance to direct cell behavior. It is argued here that present knowledge of tissue repair biology points us toward the latter approach, providing external cues which will direct how cells should organize the new tissue. This will be particularly true where we need to reproduce microscopic and ultrastructural features of the original tissue architecture. A number of such cues have been identified, and methods are already available, including substrate chemistry, substrate contact guidance, mechanical loading, and biochemical mediators to provide these cues. Examples of these are already being used with some success to control the formation of tissue structures.

  2. [New challenge of tissue repair and regenerative medicine: to achieve a perfect repair and regeneration of multiple tissues in wound sites].

    Science.gov (United States)

    Fu, X B

    2016-01-01

    Great achievements in the study of tissue repair and regeneration have been made, and many of these successes have been shown to be beneficial to the patients in recent years. However, perfect tissue repair and regeneration of damaged tissues and organs remain to be great challenges in the management of trauma and diseases. Based on the progress in developmental biology in animals and advances in stem cell biology, it is possible to attain the aim of perfect repair and regeneration by means of somatic cell reprogramming and different inducing techniques.

  3. Native Tissue Prolapse Repairs: Comparative Effectiveness Trials.

    Science.gov (United States)

    Siff, Lauren N; Barber, Matthew D

    2016-03-01

    This report reviews the success rates and complications of native tissue (nonmesh) vaginal reconstruction of pelvic organ prolapse by compartment. For apical prolapse, both uterosacral ligament suspensions and sacrospinous ligament fixations are effective and provided similar outcomes in anatomy and function with few adverse events. In the anterior compartment, traditional colporrhaphy technique is no different than ultralateral suturing. In the posterior compartment, transvaginal rectocele repair is superior to transanal repair. For uterine preservation, sacrospinous hysteropexy is not inferior to vaginal hysterectomy with uterosacral ligament suspension for treatment of apical uterovaginal prolapse. Copyright © 2016 Elsevier Inc. All rights reserved.

  4. Quantification of thermal damage in skin tissue

    Institute of Scientific and Technical Information of China (English)

    徐峰; 文婷; 卢天健; Seffen; Keith

    2008-01-01

    Skin thermal damage or skin burns are the most commonly encountered type of trauma in civilian and military communities. Besides, advances in laser, microwave and similar technologies have led to recent developments of thermal treatments for disease and damage involving skin tissue, where the objective is to induce thermal damage precisely within targeted tissue structures but without affecting the surrounding, healthy tissue. Further, extended pain sensation induced by thermal damage has also brought great...

  5. Repair of damaged supraglottic airway devices: A novel method

    Directory of Open Access Journals (Sweden)

    Kapoor Dheeraj

    2010-06-01

    Full Text Available Abstract Damage of laryngeal mask airway and other supraglottic airway devices has always been a matter of concern. Although manufacturer recommends maximum 40 uses of LMA (and its congeners but damage before 40 uses needs to be evaluated. We hereby, describe a novel method of repair of supraglottic devices when damage occurs at mask inflation line or pilot balloon valve assembly.

  6. New frontiers in biomaterials research for tissue repair and regeneration

    Institute of Scientific and Technical Information of China (English)

    Huiling Liu; Haoran Liu; Aaron Clasky; Huilin Yang; Lei Yang

    2016-01-01

    The field of biomaterials has recently emerged to augment or replace lost or damaged tissues and organs due to the human body’s limited ability to self-heal large defects. Historically, metallic components, polymers, ceramics, and composite materials were utilized as synthetic materials along with natural materials to assist in therapy. Various novel biomaterials were developed to respond to a significant amount of new medical challenges in the past decade. Therefore, there is a need to review these newly developed biomaterials and their potential to improve tissue repair and regeneration in a variety of applications. Here, we briefly review the different strategies and attempts to use novel biomaterials, including self-assembled and macromolecular biomaterials, hydrogels, metamaterials, decellularized tissues, and biomaterials obtained via synthetic biology, used either for tissue repair and regeneration or for therapeutic use by exploiting other mechanisms of healing. All these methods aim to create functional materials, devices, systems, and/or organisms with novel and useful functions on the basis of catalogued and standardized biological building blocks. This review details the various methods and introduces the applications of these biomaterials in tissue repair and regeneration, especially for bone, nerve, and skin applications.

  7. Damage diagnosis and compatible repair mortars

    NARCIS (Netherlands)

    Hees, R.P.J. van

    1999-01-01

    Mortars for repair and maintenance of historic masonry have to meet specific requirements. Several authors have made contributions, however many cases of failure show that there still is quite a lack of knowledge on the compatibility of repair mortars for historic masonry. The diagnosis of the cause

  8. Choreography of oxidative damage repair in mammalian genomes.

    Science.gov (United States)

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

    2002-07-01

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

  9. Human longevity and variation in DNA damage response and repair

    DEFF Research Database (Denmark)

    Debrabant, Birgit; Soerensen, Mette; Flachsbart, Friederike

    2014-01-01

    others. Data were applied on 592 SNPs from 77 genes involved in nine sub-processes: DNA-damage response, base excision repair (BER), nucleotide excision repair, mismatch repair, non-homologous end-joining, homologous recombinational repair (HRR), RecQ helicase activities (RECQ), telomere functioning...... and mitochondrial DNA processes. The study population was 1089 long-lived and 736 middle-aged Danes. A self-contained set-based test of all SNPs displayed association with longevity (P-value=9.9 × 10-5), supporting that the overall pathway could affect longevity. Investigation of the nine sub-processes using...

  10. PARP-1: Friend or Foe of DNA Damage and Repair in Tumorigenesis?

    Energy Technology Data Exchange (ETDEWEB)

    Swindall, Amanda F.; Stanley, Jennifer A. [Department of Radiation Oncology Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, 176F HSROC Suite 2232B, 1700 6th Avenue South, Birmingham, AL 35249 (United States); Yang, Eddy S., E-mail: eyang@uab.edu [Department of Radiation Oncology Comprehensive Cancer Center, University of Alabama at Birmingham School of Medicine, 176F HSROC Suite 2232B, 1700 6th Avenue South, Birmingham, AL 35249 (United States); Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham, AL 35249 (United States); Department of Pharmacology and Toxicology, University of Alabama at Birmingham, Birmingham, AL 35249 (United States)

    2013-07-26

    Oxidative stress induced by reactive oxygen species can result in DNA damage within cells and subsequently increase risk for carcinogenesis. This may be averted by repair of DNA damage through the base or nucleotide excision repair (BER/NER) pathways. PARP, a BER protein, is known for its role in DNA-repair. However, multiple lesions can occur within a small range of DNA, known as oxidative clustered DNA lesions (OCDLs), which are difficult to repair and may lead to the more severe DNA double-strand break (DSB). Inefficient DSB repair can then result in increased mutagenesis and neoplastic transformation. OCDLs occur more frequently within a variety of tumor tissues. Interestingly, PARP is highly expressed in several human cancers. Additionally, chronic inflammation may contribute to tumorigenesis through ROS-induced DNA damage. Furthermore, PARP can modulate inflammation through interaction with NFκB and regulating the expression of inflammatory signaling molecules. Thus, the upregulation of PARP may present a double-edged sword. PARP is needed to repair ROS-induced DNA lesions, but PARP expression may lead to increased inflammation via upregulation of NFκB signaling. Here, we discuss the role of PARP in the repair of oxidative damage versus the formation of OCDLs and speculate on the feasibility of PARP inhibition for the treatment and prevention of cancers by exploiting its role in inflammation.

  11. DNA-damage foci to detect and characterize DNA repair alterations in children treated for pediatric malignancies.

    Directory of Open Access Journals (Sweden)

    Nadine Schuler

    Full Text Available PURPOSE: In children diagnosed with cancer, we evaluated the DNA damage foci approach to identify patients with double-strand break (DSB repair deficiencies, who may overreact to DNA-damaging radio- and chemotherapy. In one patient with Fanconi anemia (FA suffering relapsing squamous cell carcinomas of the oral cavity we also characterized the repair defect in biopsies of skin, mucosa and tumor. METHODS AND MATERIALS: In children with histologically confirmed tumors or leukemias and healthy control-children DSB repair was investigated by counting γH2AX-, 53BP1- and pATM-foci in blood lymphocytes at defined time points after ex-vivo irradiation. This DSB repair capacity was correlated with treatment-related normal-tissue responses. For the FA patient the defective repair was also characterized in tissue biopsies by analyzing DNA damage response proteins by light and electron microscopy. RESULTS: Between tumor-children and healthy control-children we observed significant differences in mean DSB repair capacity, suggesting that childhood cancer is based on genetic alterations affecting DNA repair. Only 1 out of 4 patients with grade-4 normal-tissue toxicities revealed an impaired DSB repair capacity. The defective DNA repair in FA patient was verified in irradiated blood lymphocytes as well as in non-irradiated mucosa and skin biopsies leading to an excessive accumulation of heterochromatin-associated DSBs in rapidly cycling cells. CONCLUSIONS: Analyzing human tissues we show that DSB repair alterations predispose to cancer formation at younger ages and affect the susceptibility to normal-tissue toxicities. DNA damage foci analysis of blood and tissue samples allows one to detect and characterize DSB repair deficiencies and enables identification of patients at risk for high-grade toxicities. However, not all treatment-associated normal-tissue toxicities can be explained by DSB repair deficiencies.

  12. Inducible repair of oxidative DNA damage in Escherichia coli.

    Science.gov (United States)

    Demple, B; Halbrook, J

    Hydrogen peroxide is lethal to many cell types, including the bacterium Escherichia coli. Peroxides yield transient radical species that can damage DNA and cause mutations. Such partially reduced oxygen species are occasionally released during cellular respiration and are generated by lethal and mutagenic ionizing radiation. Because cells live in an environment where the threat of oxidative DNA damage is continual, cellular mechanisms may have evolved to avoid and repair this damage. Enzymes are known which evidently perform these functions. We report here that resistance to hydrogen peroxide toxicity can be induced in E. coli, that this novel induction is specific and occurs, in part, at the level of DNA repair.

  13. Immunohistochemical analysis of oxidative stress and DNA repair proteins in normal mammary and breast cancer tissues

    Directory of Open Access Journals (Sweden)

    Nardulli Ann M

    2010-01-01

    Full Text Available Abstract Background During the course of normal cellular metabolism, oxygen is consumed and reactive oxygen species (ROS are produced. If not effectively dissipated, ROS can accumulate and damage resident proteins, lipids, and DNA. Enzymes involved in redox regulation and DNA repair dissipate ROS and repair the resulting damage in order to preserve a functional cellular environment. Because increased ROS accumulation and/or unrepaired DNA damage can lead to initiation and progression of cancer and we had identified a number of oxidative stress and DNA repair proteins that influence estrogen responsiveness of MCF-7 breast cancer cells, it seemed possible that these proteins might be differentially expressed in normal mammary tissue, benign hyperplasia (BH, ductal carcinoma in situ (DCIS and invasive breast cancer (IBC. Methods Immunohistochemistry was used to examine the expression of a number of oxidative stress proteins, DNA repair proteins, and damage markers in 60 human mammary tissues which were classified as BH, DCIS or IBC. The relative mean intensity was determined for each tissue section and ANOVA was used to detect statistical differences in the relative expression of BH, DCIS and IBC compared to normal mammary tissue. Results We found that a number of these proteins were overexpressed and that the cellular localization was altered in human breast cancer tissue. Conclusions Our studies suggest that oxidative stress and DNA repair proteins not only protect normal cells from the damaging effects of ROS, but may also promote survival of mammary tumor cells.

  14. Damage tolerance of bonded composite aircraft repairs for metallic structures

    Science.gov (United States)

    Clark, Randal John

    This thesis describes the development and validation of methods for damage tolerance substantiation of bonded composite repairs applied to cracked plates. This technology is used to repair metal aircraft structures, offering improvements in fatigue life, cost, manufacturability, and inspectability when compared to riveted repairs. The work focuses on the effects of plate thickness and bending on repair life, and covers fundamental aspects of fracture and fatigue of cracked plates and bonded joints. This project falls under the UBC Bonded Composite Repair Program, which has the goal of certification and widespread use of bonded repairs in civilian air transportation. This thesis analyses the plate thickness and transverse stress effects on fracture of repaired plates and the related problem of induced geometrically nonlinear bending in unbalanced (single-sided) repairs. The author begins by developing a classification scheme for assigning repair damage tolerance substantiation requirements based upon stress-based adhesive fracture/fatigue criteria and the residual strength of the original structure. The governing equations for bending of cracked plates are then reformulated and line-spring models are developed for linear and nonlinear coupled bending and extension of reinforced cracks. The line-spring models were used to correct the Wang and Rose energy method for the determination of the long-crack limit stress intensity, and to develop a new interpolation model for repaired cracks of arbitrary length. The analysis was validated using finite element models and data from mechanical tests performed on hybrid bonded joints and repair specimens that are representative of an in-service repair. This work will allow designers to evaluate the damage tolerance of the repaired plate, the adhesive, and the composite patch, which is an airworthiness requirement under FAR (Federal Aviation Regulations) 25.571. The thesis concludes by assessing the remaining barriers to

  15. Repair of ultraviolet-light-induced damage

    Energy Technology Data Exchange (ETDEWEB)

    Sutherland, B.M.

    1981-01-01

    Studies are reviewed which present three major new findings in the photobiology of skin. First, detectable numbers of dimers are formed even at sub-erythymal doses. Second, excision of dimers is much more rapid than would be predicted from results obtained in cell culture. Third, comparison of the rates of excision and photoreactivation in skin indicates that in normal sunlight exposure, photoreactivation may well be the predominant repair pathway in skin. (ACR)

  16. Repairing Damaged Power-Cable Insulation

    Science.gov (United States)

    Baker, G. E.

    1984-01-01

    Simple method saves time, money, and material. In new method cable remains in place while new insulation is applied to damaged portion. Method results in new terminations with safety factor equal to that of any portion of cable.

  17. Differential repair of UV damage in Saccharomyces cerevisiae.

    Science.gov (United States)

    Terleth, C; van Sluis, C A; van de Putte, P

    1989-06-26

    Preferential repair of UV-induced damage is a phenomenon by which mammalian cells might enhance their survival. This paper presents the first evidence that preferential repair occurs in the lower eukaryote Saccharomyces cerevisiae. Moreover an unique approach is reported to compare identical sequences present on the same chromosome and only differing in expression. We determined the removal of pyrimidine dimers from two identical alpha-mating type loci and we were able to show that the active MAT alpha locus is repaired preferentially to the inactive HML alpha locus. In a sir-3 mutant, in which both loci are active this preference is not observed.

  18. Biomarkers of oxidative damage to DNA and repair

    DEFF Research Database (Denmark)

    Loft, Steffen; Høgh Danielsen, Pernille; Mikkelsen, Lone

    2008-01-01

    Oxidative-stress-induced damage to DNA includes a multitude of lesions, many of which are mutagenic and have multiple roles in cancer and aging. Many lesions have been characterized by MS-based methods after extraction and digestion of DNA. These preparation steps may cause spurious base oxidation...... DNA glycosylase 1), responsible for repair of 8-oxodG, by genotyping. Products of repair in DNA or the nucleotide pool, such as 8-oxodG, excreted into the urine can be assessed by MS-based methods and generally reflects the rate of damage. Experimental and population-based studies indicate that many...

  19. DNA damage, repair and tanning acceleration

    NARCIS (Netherlands)

    Vink, A.A.; Berg, P.T.M. van den; Roza, L.

    1999-01-01

    Exposure of the skin to solar ultraviolet radiation (UV) leads to various adverse effects, such as the induction of cellular damage and mutations, suppression of the skin's immune system, and the induction of skin cancer. These effects are the consequence of various molecular alterations in the skin

  20. Tissue damage thresholds during therapeutic electrical stimulation

    Science.gov (United States)

    Cogan, Stuart F.; Ludwig, Kip A.; Welle, Cristin G.; Takmakov, Pavel

    2016-04-01

    Objective. Recent initiatives in bioelectronic modulation of the nervous system by the NIH (SPARC), DARPA (ElectRx, SUBNETS) and the GlaxoSmithKline Bioelectronic Medicines effort are ushering in a new era of therapeutic electrical stimulation. These novel therapies are prompting a re-evaluation of established electrical thresholds for stimulation-induced tissue damage. Approach. In this review, we explore what is known and unknown in published literature regarding tissue damage from electrical stimulation. Main results. For macroelectrodes, the potential for tissue damage is often assessed by comparing the intensity of stimulation, characterized by the charge density and charge per phase of a stimulus pulse, with a damage threshold identified through histological evidence from in vivo experiments as described by the Shannon equation. While the Shannon equation has proved useful in assessing the likely occurrence of tissue damage, the analysis is limited by the experimental parameters of the original studies. Tissue damage is influenced by factors not explicitly incorporated into the Shannon equation, including pulse frequency, duty cycle, current density, and electrode size. Microelectrodes in particular do not follow the charge per phase and charge density co-dependence reflected in the Shannon equation. The relevance of these factors to tissue damage is framed in the context of available reports from modeling and in vivo studies. Significance. It is apparent that emerging applications, especially with microelectrodes, will require clinical charge densities that exceed traditional damage thresholds. Experimental data show that stimulation at higher charge densities can be achieved without causing tissue damage, suggesting that safety parameters for microelectrodes might be distinct from those defined for macroelectrodes. However, these increased charge densities may need to be justified by bench, non-clinical or clinical testing to provide evidence of device

  1. Apparatus for enhancing tissue repair in mammals

    Science.gov (United States)

    Goodwin, Thomas J. (Inventor); Parker, Clayton R. (Inventor)

    2007-01-01

    An apparatus is disclosed for enhancing tissue repair in mammals, with the apparatus comprising: a sleeve for encircling a portion of a mammalian body part, said sleeve comprising an electrically conductive coil capable of generating an electromagnetic field when an electrical current is applied thereto, means for supporting the sleeve on the mammalian body part; and means for supplying the electrically conductive coil with a square wave time varying electrical current sufficient to create a time varying electromagnetic force of from approximately 0.05 gauss to 0.05 gauss within the interior of the coil in order that when the sleeve is placed on a mammalian body part and the time varying electromagnetic force of from approximately 0.05 gauss to 0.05 gauss is generated on the mammalian body part for an extended period of time, tissue regeneration within the mammalian body part is increased to a rate in excess of the normal tissue regeneration rate that would occur without application of the time varying electromagnetic force.

  2. ECM-Chitosan Bandage for Tissue Repair

    Science.gov (United States)

    Lauto, Antonio; Longo, Leonardo

    2010-05-01

    Extracellular matrices (ECMs) are currently applied in reconstructive surgery to enhance wound healing and tissue remodelling. Sutures and staples are usually employed to stabilize ECM on tissue although they may damage the matrix structure. In this investigation, a novel biocompatible bandage was developed to implant ECM on tissue without sutures. An adhesive film, based on chitosan, was integrated with small intestine submucosa (SIS) in a single bandage strip. This bandage was bonded to sheep small intestine upon laser irradiation of the chitosan film (P = 0.12 W, Fluence = 46±1 J/cm2) to assess tissue adhesion strength. Thermocouples were used to estimate temperatures under SIS during laser irradiation. The bandage successfully bonded to intestine achieving a shear stress of 9.6±1.6 kPa(n = 15). During laser irradiation, the temperature increased modestly to 31±2 0C(n = 14) beneath the ECM portion of the bandage. The SIS-chitosan bandage bonded effectively to tissue without sutures and preserved the ECM structure avoiding irreversible thermal denaturation of imbedded bioactive proteins.

  3. UV Radiation Damage and Bacterial DNA Repair Systems

    Science.gov (United States)

    Zion, Michal; Guy, Daniel; Yarom, Ruth; Slesak, Michaela

    2006-01-01

    This paper reports on a simple hands-on laboratory procedure for high school students in studying both radiation damage and DNA repair systems in bacteria. The sensitivity to ultra-violet (UV) radiation of both "Escherichia coli" and "Serratia marcescens" is tested by radiating them for varying time periods. Two growth temperatures are used in…

  4. Bioactive Polymeric Materials for Tissue Repair

    Directory of Open Access Journals (Sweden)

    Diane R. Bienek

    2017-01-01

    Full Text Available Bioactive polymeric materials based on calcium phosphates have tremendous appeal for hard tissue repair because of their well-documented biocompatibility. Amorphous calcium phosphate (ACP-based ones additionally protect against unwanted demineralization and actively support regeneration of hard tissue minerals. Our group has been investigating the structure/composition/property relationships of ACP polymeric composites for the last two decades. Here, we present ACP’s dispersion in a polymer matrix and the fine-tuning of the resin affects the physicochemical, mechanical, and biological properties of ACP polymeric composites. These studies illustrate how the filler/resin interface and monomer/polymer molecular structure affect the material’s critical properties, such as ion release and mechanical strength. We also present evidence of the remineralization efficacy of ACP composites when exposed to accelerated acidic challenges representative of oral environment conditions. The utility of ACP has recently been extended to include airbrushing as a platform technology for fabrication of nanofiber scaffolds. These studies, focused on assessing the feasibility of incorporating ACP into various polymer fibers, also included the release kinetics of bioactive calcium and phosphate ions from nanofibers and evaluate the biorelevance of the polymeric ACP fiber networks. We also discuss the potential for future integration of the existing ACP scaffolds into therapeutic delivery systems used in the precision medicine field.

  5. Tissue damage and oxidant/antioxidant balance.

    Science.gov (United States)

    Kisaoglu, Abdullah; Borekci, Bunyamin; Yapca, O Erkan; Bilen, Habib; Suleyman, Halis

    2013-02-01

    The oxidant/antioxidant balance in healthy tissues is maintained with a predominance of antioxidants. Various factors that can lead to tissue damage disrupt the oxidant/antioxidant balance in favor of oxidants. In this study, disruptions of the oxidant/antioxidant balance in favor of oxidants were found to be a consequence of the over-consumption of antioxidants. For this reason, antioxidants are considered to be of importance in the prevention and treatment of various types of tissue damage that are aggravated by stress.

  6. Damage and repair of ancient DNA

    DEFF Research Database (Denmark)

    Mitchell, David; Willerslev, Eske; Hansen, Anders

    2005-01-01

    , and extensive degradation. In the course of this review, we will discuss the current aDNA literature describing the importance of aDNA studies as they relate to important biological questions and the difficulties associated with extracting useful information from highly degraded and damaged substrates derived......Under certain conditions small amounts of DNA can survive for long periods of time and can be used as polymerase chain reaction (PCR) substrates for the study of phylogenetic relationships and population genetics of extinct plants and animals, including hominids. Because of extensive DNA...... degradation, these studies are limited to species that lived within the past 10(4)-10(5) years (Late Pleistocene), although DNA sequences from 10(6) years have been reported. Ancient DNA (aDNA) has been used to study phylogenetic relationships of protists, fungi, algae, plants, and higher eukaryotes...

  7. UV exposed electronically activated damage and photoreactivation repair

    Science.gov (United States)

    Bohr, Henrik; Malik, Bary

    2007-03-01

    An investigation of the possible physics underlying the damage caused to DNA by UV radiation and its subsequent repair via a photoreactivation mechanism is presented in this study. An electronic pathway starting from the initial damage to the final repair process is proposed. UV radiation is absorbed to create a hole-excited thymine or other pyrimidine that subsequently is responsible for the formation of the thymine dimer. The negative-ion of the cofactor riboflavin, FADH-, formed by the exposure of the photolyase protein to visible light interacts with the hole-excited electronic orbital of the thymine dimer inducing a photon-less Auger transition, which restores the two thymines to the ground state, thereby detaching the lesion and repairing the DNA. Due to energy balance, the process has to involve an electronic excited state (s). The mechanism involves the least amount of energy dissipation and is charge neutral. It also avoids radiation damage in the repair process, that is, is a radiationless process.

  8. Decreased repair of gamma damaged DNA in progeria

    Energy Technology Data Exchange (ETDEWEB)

    Rainbow, A.J.; Howes, M.

    1977-01-01

    A sensitive host-cell reactivation technique was used to examine the DNA repair ability of fibroblasts from two patients with classical progeria. Fibroblasts were infected with either non-irradiated or gamma-irradiated adenovirus type 2 and at 48 hrs after infection cells were examined for the presence of viral structural antigens using immunofluorescent staining. The production of viral structural antigens was considerably reduced in the progeria lines as compared to normal fibroblasts when gamma-irradiated virus was used, indicating a defect in the repair of gamma ray damaged DNA in the progeria cells.

  9. Protein damage and repair controlling seed vigor and longevity.

    Science.gov (United States)

    Ogé, Laurent; Broyart, Caroline; Collet, Boris; Godin, Béatrice; Jallet, Denis; Bourdais, Gildas; Job, Dominique; Grappin, Philippe

    2011-01-01

    The formation of abnormal isoaspartyl residues derived from aspartyl or asparaginyl residues is a major source of spontaneous protein misfolding in cells. The repair enzyme protein L: -isoaspartyl methyltransferase (PIMT) counteracts such damage by catalyzing the conversion of abnormal isoaspartyl residues to their normal aspartyl forms. Thus, this enzyme contributes to the survival of many organisms, including plants. Analysis of the accumulation of isoaspartyl-containing proteins and its modulation by the PIMT repair pathway, using germination tests, immunodetection, enzymatic assays, and HPLC analysis, gives new insights in understanding controlling mechanisms of seed longevity and vigor.

  10. Homologous recombination in DNA repair and DNA damage tolerance

    Institute of Scientific and Technical Information of China (English)

    Xuan Li; Wolf-Dietrich Heyer

    2008-01-01

    Homologous recombination (HR) comprises a series of interrelated pathways that function in the repair of DNA double-stranded breaks (DSBs) and interstrand crosslinks (ICLs). In addition, recombination provides critical sup-port for DNA replication in the recovery of stalled or broken replication forks, contributing to tolerance of DNA damage. A central core of proteins, most critically the RecA homolog Rad51, catalyzes the key reactions that typify HR: homology search and DNA strand invasion. The diverse functions of recombination are reflected in the need for context-specific factors that perform supplemental functions in conjunction with the core proteins. The inability to properly repair complex DNA damage and resolve DNA replication stress leads to genomic instability and contributes to cancer etiology. Mutations in the BRCA2 recombination gene cause predisposition to breast and ovarian cancer as well as Fanconi anemia, a cancer predisposition syndrome characterized by a defect in the repair of DNA interstrand crosslinks. The cellular functions of recombination are also germane to DNA-based treatment modaUties of cancer, which target replicating cells by the direct or indirect induction of DNA lesions that are substrates for recombination pathways. This review focuses on mechanistic aspects of HR relating to DSB and ICL repair as well as replication fork support.

  11. Simulated microgravity influenced the expression of DNA damage repair genes

    Science.gov (United States)

    Zhang, Meng; Sun, Yeqing; Jiawei, Liu; Wang, Ting

    2016-07-01

    Ionizing radiation and microgravity were considered to be the most important stress factors of space environmental the respective study of the biological effects of the radiation and microgravity carried out earlier, but the interaction of the effects of radiation with microgravity started later, and due to difference of the materials and methods the result of this experiment were not consistent. To further investigate the influence of microgravity on the expression of the radiation damage repair genes, the seed of Arabidopsis (Col) and its gravity-insensitive mutant (PIN2) were exposed to 0.1Gy of the dose of energetic carbon-ion beam radiation (LET = 30KeV / μm), and the germinated seed were than fixed in the 3D random positioning apparatus immediately for a 10-day simulated microgravity. By measuring the deflection angle of root tip and the changes of the expression of Ku70 and RAD51 protein, we investigated the impact of microgravity effect on radiation damage repair systems. The results shown that radiation, microgravity and microgravity with radiation could increase the angle of the root of the Col significantly, but no obvious effect on PIN2 type. The radiation could increase the expression of Ku70 significantly in both Col and PIN2, microgravity does not affect the expression, but the microgravity with radiation could decrease the expression of Ku70. This result shown that the microgravity could influence the radiation damage repair systems in molecular level. Moreover, our findings were important to understand the molecular mechanism of the impact of microgravity effect on radiation damage repair systems in vivo.

  12. Disease related tissue damage and subsequent changes in fillet structure

    DEFF Research Database (Denmark)

    Fish meat quality is influenced by many biological and physical factors like e.g. rearing, feeding, slaughtering, processing and storage. Observations from practical fish farming indicate that infections in e.g. salmon caused by Moritella viscosus or Pancreas Disease (PD) results in downgrading o......-regulation of immune-related genes followed by a regenerative phase with regulation of genes coding for muscle growth and synthesis of connective tissue....... of the fish and subsequent a reduction in price. Despite this, the impact of infectious diseases on the meat quality and the mechanisms behind are poorly investigated. Wound repair is a dynamic, interactive response to tissue injury that involves a complex interaction and cross talk of various cell types......, extracellular matrix molecules, soluble mediators and cytokines. In order to describe the molecular mechanisms and processes of wound repair, a panel of genes covering immunological factors and tissue regeneration were used to measure changes at the mRNA level following mechanical tissue damage in rainbow trout...

  13. Lin28 enhances tissue repair by reprogramming cellular metabolism.

    Science.gov (United States)

    Shyh-Chang, Ng; Zhu, Hao; Yvanka de Soysa, T; Shinoda, Gen; Seligson, Marc T; Tsanov, Kaloyan M; Nguyen, Liem; Asara, John M; Cantley, Lewis C; Daley, George Q

    2013-11-07

    Regeneration capacity declines with age, but why juvenile organisms show enhanced tissue repair remains unexplained. Lin28a, a highly conserved RNA-binding protein expressed during embryogenesis, plays roles in development, pluripotency, and metabolism. To determine whether Lin28a might influence tissue repair in adults, we engineered the reactivation of Lin28a expression in several models of tissue injury. Lin28a reactivation improved hair regrowth by promoting anagen in hair follicles and accelerated regrowth of cartilage, bone, and mesenchyme after ear and digit injuries. Lin28a inhibits let-7 microRNA biogenesis; however, let-7 repression was necessary but insufficient to enhance repair. Lin28a bound to and enhanced the translation of mRNAs for several metabolic enzymes, thereby increasing glycolysis and oxidative phosphorylation (OxPhos). Lin28a-mediated enhancement of tissue repair was negated by OxPhos inhibition, whereas a pharmacologically induced increase in OxPhos enhanced repair. Thus, Lin28a enhances tissue repair in some adult tissues by reprogramming cellular bioenergetics. PAPERCLIP: Copyright © 2013 Elsevier Inc. All rights reserved.

  14. The myofibroblast, multiple origins for major roles in normal and pathological tissue repair

    Directory of Open Access Journals (Sweden)

    Micallef Ludovic

    2012-06-01

    Full Text Available Abstract Myofibroblasts differentiate, invade and repair injured tissues by secreting and organizing the extracellular matrix and by developing contractile forces. When tissues are damaged, tissue homeostasis must be re-established, and repair mechanisms have to rapidly provide harmonious mechanical tissue organization, a process essentially supported by (myofibroblasts. Under physiological conditions, the secretory and contractile activities of myofibroblasts are terminated when the repair is complete (scar formation but the functionality of the tissue is only rarely perfectly restored. At the end of the normal repair process, myofibroblasts disappear by apoptosis but in pathological situations, myofibroblasts likely remain leading to excessive scarring. Myofibroblasts originate from different precursor cells, the major contribution being from local recruitment of connective tissue fibroblasts. However, local mesenchymal stem cells, bone marrow-derived mesenchymal stem cells and cells derived from an epithelial-mesenchymal transition process, may represent alternative sources of myofibroblasts when local fibroblasts are not able to satisfy the requirement for these cells during repair. These diverse cell types probably contribute to the appearance of myofibroblast subpopulations which show specific biological properties and which are important to understand in order to develop new therapeutic strategies for treatment of fibrotic and scarring diseases.

  15. Probing and repairing damaged surfaces with nanoparticle-containing microcapsules

    Science.gov (United States)

    Kratz, Katrina; Narasimhan, Amrit; Tangirala, Ravisubhash; Moon, Sungcheal; Revanur, Ravindra; Kundu, Santanu; Kim, Hyun Suk; Crosby, Alfred J.; Russell, Thomas P.; Emrick, Todd; Kolmakov, German; Balazs, Anna C.

    2012-02-01

    Nanoparticles have useful properties, but it is often important that they only start working after they are placed in a desired location. The encapsulation of nanoparticles allows their function to be preserved until they are released at a specific time or location, and this has been exploited in the development of self-healing materials and in applications such as drug delivery. Encapsulation has also been used to stabilize and control the release of substances, including flavours, fragrances and pesticides. We recently proposed a new technique for the repair of surfaces called `repair-and-go'. In this approach, a flexible microcapsule filled with a solution of nanoparticles rolls across a surface that has been damaged, stopping to repair any defects it encounters by releasing nanoparticles into them, then moving on to the next defect. Here, we experimentally demonstrate the repair-and-go approach using droplets of oil that are stabilized with a polymer surfactant and contain CdSe nanoparticles. We show that these microcapsules can find the cracks on a surface and selectively deliver the nanoparticle contents into the crack, before moving on to find the next crack. Although the microcapsules are too large to enter the cracks, their flexible walls allow them to probe and adhere temporarily to the interior of the cracks. The release of nanoparticles is made possible by the thin microcapsule wall (comparable to the diameter of the nanoparticles) and by the favourable (hydrophobic-hydrophobic) interactions between the nanoparticle and the cracked surface.

  16. Delayed repair of radiation induced clustered DNA damage: Friend or foe?

    Energy Technology Data Exchange (ETDEWEB)

    Eccles, Laura J., E-mail: laura.eccles@rob.ox.ac.uk [DNA Damage Group, Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ (United Kingdom); O' Neill, Peter, E-mail: peter.oneill@rob.ox.ac.uk [DNA Damage Group, Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ (United Kingdom); Lomax, Martine E., E-mail: martine.lomax@rob.ox.ac.uk [DNA Damage Group, Gray Institute for Radiation Oncology and Biology, University of Oxford, Old Road Campus Research Building, Roosevelt Drive, Oxford OX3 7DQ (United Kingdom)

    2011-06-03

    A signature of ionizing radiation exposure is the induction of DNA clustered damaged sites, defined as two or more lesions within one to two helical turns of DNA by passage of a single radiation track. Clustered damage is made up of double strand breaks (DSB) with associated base lesions or abasic (AP) sites, and non-DSB clusters comprised of base lesions, AP sites and single strand breaks. This review will concentrate on the experimental findings of the processing of non-DSB clustered damaged sites. It has been shown that non-DSB clustered damaged sites compromise the base excision repair pathway leading to the lifetime extension of the lesions within the cluster, compared to isolated lesions, thus the likelihood that the lesions persist to replication and induce mutation is increased. In addition certain non-DSB clustered damaged sites are processed within the cell to form additional DSB. The use of E. coli to demonstrate that clustering of DNA lesions is the major cause of the detrimental consequences of ionizing radiation is also discussed. The delayed repair of non-DSB clustered damaged sites in humans can be seen as a 'friend', leading to cell killing in tumour cells or as a 'foe', resulting in the formation of mutations and genetic instability in normal tissue.

  17. Hematopoietic tissue repair under chronic low daily dose irradiation

    Energy Technology Data Exchange (ETDEWEB)

    Seed, T.M.

    1994-12-01

    The capacity of the hematopoietic system to repair constantly accruing cellular damage under chronic, low daily dose gamma irradiation is essential for the maintenance of a functional hematopoietic system, and, in turn, long term survival. In certain individuals, however, such continuous cycles of damage and repair provide an essential inductive environment for selected types of hematopathologies, e.g., myeloid leukemia (ML). We have been studying temporal and causal relationships between hematopoietic capacity, associated repair functions, and propensities for hematologic disease in canines under variable levels of chronic radiation stress (0.3{minus}26.3 cGy d{sup {minus}1}). Results indicate that the maximum exposure rate tolerated by the hematopoietic system is highly individual-specific and is based largely on the degree to which repair capacity, and, in turn, hematopoietic restoration, is augmented under chronic exposure. In low-tolerance individuals (prone to aplastic anemia, subgroup (1), the failure to augment basic m-pair functions seemingly results in a progressive accumulation of genetic and cellular damage within vital progenitorial marrow compartments particularly marked within erythroid compartments. that results in loss of reproductive capacity and ultimately in collapse of the hematopoietic system. The high-tolerance individuals (radioaccomodated and either prone- or not prone to ML, subgroup 2 & 3 appear to minimize the accumulating damage effect of daily exposures by extending repair functions, which preserves reproductive integrity and fosters regenerative hematopoietic responses. As the strength of the regenerative response manifests the extent of repair augmentation, the relatively strong response of high- tolerance individuals progressing to patent ML suggests an insufficiency of repair quality rather than repair quantity.

  18. Extra lethal damage due to residual incompletely repaired sublethal damage in hyperfractionated and continuous radiation treatment

    Energy Technology Data Exchange (ETDEWEB)

    Chen, J.; van de Geijn, J.; Goffman, T. (ROB, DCT, NCI, NIH, Bethesda, Maryland 20892 (US))

    1991-05-01

    In the conventional linear--quadratic model of single-dose response, the {alpha} and {beta} terms reflect lethal damage created {ital during} the delivery of a dose, from two different presumed molecular processes, one linear with dose, the other quadratic. With the conventional one-fraction-per-day (or less) regimens, the sublethal damage (SLD), presumably repairing exponentially over time, is essentially completely fixed by the time of the next dose of radiation. If this assumption is true, the effects of subsequent fractions of radiation should be independent, that is, there should be little, if any, reversible damage left from previous fractions, at the time of the next dose. For multiple daily fractions, or for the limiting case, continuous radiation, this simplification may overlook damaged cells that have had insufficient time for repair. A generalized method is presented for accounting for extra lethal damage (ELD) arising from such residual SLD for hyperfractionation and continuous irradiation schemes. It may help to predict differences in toxicity and tumor control, if any, obtained with unconventional'' treatment regimens. A key element in the present model is the finite size and the dynamic character of the pool of sublethal damage. Besides creating the usual linear and quadratic components of lethal damage, each new fraction converts a certain fraction of the existing SLD into ELD, and creates some new SLD.

  19. 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.

  20. Tissue injury and repair following cutaneous exposure of mice to sulfur mustard.

    Science.gov (United States)

    Joseph, Laurie B; Composto, Gabriella M; Heck, Diane E

    2016-08-01

    In mouse skin, sulfur mustard (SM) is a potent vesicant, damaging both the epidermis and the dermis. The extent of wounding is dependent on the dose of SM and the duration of exposure. Initial responses include erythema, pruritus, edema, and xerosis; this is followed by an accumulation of inflammatory leukocytes in the tissue, activation of mast cells, and the release of mediators, including proinflammatory cytokines and bioactive lipids. These proinflammatory mediators contribute to damaging the epidermis, hair follicles, and sebaceous glands and to disruption of the epidermal basement membrane. This can lead to separation of the epidermis from the dermis, resulting in a blister, which ruptures, leading to the formation of an eschar. The eschar stimulates the formation of a neoepidermis and wound repair and may result in persistent epidermal hyperplasia. Epidermal damage and repair is associated with upregulation of enzymes generating proinflammatory and pro-growth/pro-wound healing mediators, including cyclooxygenase-2, which generates prostanoids, inducible nitric oxide synthase, which generates nitric oxide, fibroblast growth factor receptor 2, and galectin-3. Characterization of the mediators regulating structural changes in the skin during SM-induced tissue damage and wound healing will aid in the development of therapeutic modalities to mitigate toxicity and stimulate tissue repair processes. © 2016 New York Academy of Sciences.

  1. Recombinant human erythropoietin for repair of white matter damage

    Institute of Scientific and Technical Information of China (English)

    Wei Zhou; Xiao Rong; Li Tao; Weineng Lu

    2011-01-01

    Erythropoietin has been shown to exhibit neuroprotective effects in animal models. A neonatal rat model of hypoxic-ischemic white matter damage was established via bilateral carotid artery ligation in 4-day-old Sprague-Dawley rats. The rats were subsequently treated with recombinant human erythropoietin to observe pathological changes in the brain and long-term neurobehavioral functions before and after intervention. Results showed that the number of myelin basic protein-positive cells, which reflected myelin/oligodendrocyte damage, significantly increased, although the number of amyloid precursor protein-positive cells, which reflected axonal injury, significantly decreased in periventricular white matter at 72 hours and 7 days following erythropoietin intervention. The number of glial fibrillary acidic protein-positive cells, indicating astrocytic damage, significantly decreased in periventricular white matter of erythropoietin-treated rats at 48 hours, 72 hours, 7 days, and 26 days. Following erythropoietin intervention in the 30-day-old rats, head-turning time in the slope test was shortened and open-field test scores increased. These results suggested that erythropoietin promoted repair of white matter damage, as well as improved neurobehavioral functions in a rat model of hypoxic-ischemic injury.

  2. miRNA control of tissue repair and regeneration.

    Science.gov (United States)

    Sen, Chandan K; Ghatak, Subhadip

    2015-10-01

    Tissue repair and regeneration rely on the function of miRNA, molecular silencers that enact post-transcriptional gene silencing of coding genes. Disruption of miRNA homeostasis is developmentally lethal, indicating that fetal tissue development is tightly controlled by miRNAs. Multiple critical facets of adult tissue repair are subject to control by miRNAs, as well. Sources of cell pool for tissue repair and regeneration are diverse and provided by processes including cellular dedifferentiation, transdifferentiation, and reprogramming. Each of these processes is regulated by miRNAs. Furthermore, induced pluripotency may be achieved by miRNA-based strategies independent of transcription factor manipulation. The observation that miRNA does not integrate into the genome makes miRNA-based therapeutic strategies translationally valuable. Tools to manipulate cellular and tissue miRNA levels include mimics and inhibitors that may be specifically targeted to cells of interest at the injury site. Here, we discuss the extraordinary importance of miRNAs in tissue repair and regeneration based on emergent reports and rapid advances in miRNA-based therapeutics.

  3. Fibrocytes and the tissue niche in lung repair

    Directory of Open Access Journals (Sweden)

    Bjermer Leif

    2011-06-01

    Full Text Available Abstract Human fibrocytes are bone marrow-derived mesenchymal progenitor cells that express a variety of markers related to leukocytes, hematopoietic stem cells and a diverse set of fibroblast phenotypes. Fibrocytes can be recruited from the circulation to the tissue where they further can differentiate and proliferate into various mesenchymal cell types depending on the tissue niche. This local tissue niche is important because it modulates the fibrocytes and coordinates their role in tissue behaviour and repair. However, plasticity of a niche may be co-opted in chronic airway diseases such as asthma, idiopathic pulmonary fibrosis and obliterative bronchiolitis. This review will therefore focus on a possible role of fibrocytes in pathological tissue repair processes in those diseases.

  4. The 23rd Annual Meeting of the European Tissue Repair Society (ETRS) in Reims, France

    NARCIS (Netherlands)

    Hoff, J.W. Von den; Agren, M.S.; Coulomb, B.; Eming, S.A.; Lataillade, J.J.

    2014-01-01

    The 23rd Annual Meeting of the European Tissue Repair Society, Reims, France, October 23 to 25, 2013 focused on tissue repair and regenerative medicine covering topics such as stem cells, biomaterials, tissue engineering, and burns.

  5. Matrix metalloproteinase-8 overexpression prevents proper tissue repair

    DEFF Research Database (Denmark)

    Danielsen, Patricia Louise; Holst, Anders V; Maltesen, Henrik R

    2011-01-01

    The collagenolytic matrix metalloproteinase-8 (MMP-8) is essential for normal tissue repair but is often overexpressed in wounds with disrupted healing. Our aim was to study the impact of a local excess of this neutrophil-derived proteinase on wound healing using recombinant adenovirus-driven tra......The collagenolytic matrix metalloproteinase-8 (MMP-8) is essential for normal tissue repair but is often overexpressed in wounds with disrupted healing. Our aim was to study the impact of a local excess of this neutrophil-derived proteinase on wound healing using recombinant adenovirus...

  6. International congress on DNA damage and repair: Book of abstracts

    Energy Technology Data Exchange (ETDEWEB)

    1987-01-01

    This document contains the abstracts of 105 papers presented at the Congress. Topics covered include the Escherichia coli nucleotide excision repair system, DNA repair in malignant transformations, defective DNA repair, and gene regulation. (TEM)

  7. Nrf2 as a master regulator of tissue damage control and disease tolerance to infection.

    Science.gov (United States)

    Soares, Miguel P; Ribeiro, Ana M

    2015-08-01

    Damage control refers to those actions made towards minimizing damage or loss. Depending on the context, these can range from emergency procedures dealing with the sinking of a ship or to a surgery dealing with severe trauma or even to an imaginary company in Marvel comics, which repairs damaged property arising from conflicts between super heroes and villains. In the context of host microbe interactions, tissue damage control refers to an adaptive response that limits the extent of tissue damage associated with infection. Tissue damage control can limit the severity of infectious diseases without interfering with pathogen burden, conferring disease tolerance to infection. This contrasts with immune-driven resistance mechanisms, which although essential to protect the host from infection, can impose tissue damage to host parenchyma tissues. This damaging effect is countered by stress responses that confer tissue damage control and disease tolerance to infection. Here we discuss how the stress response regulated by the transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) acts in such a manner. © 2015 Authors.

  8. Nrf2 as a master regulator of tissue damage control and disease tolerance to infection

    Science.gov (United States)

    Soares, Miguel P.; Ribeiro, Ana M.

    2015-01-01

    Damage control refers to those actions made towards minimizing damage or loss. Depending on the context, these can range from emergency procedures dealing with the sinking of a ship or to a surgery dealing with severe trauma or even to an imaginary company in Marvel comics, which repairs damaged property arising from conflicts between super heroes and villains. In the context of host microbe interactions, tissue damage control refers to an adaptive response that limits the extent of tissue damage associated with infection. Tissue damage control can limit the severity of infectious diseases without interfering with pathogen burden, conferring disease tolerance to infection. This contrasts with immune-driven resistance mechanisms, which although essential to protect the host from infection, can impose tissue damage to host parenchyma tissues. This damaging effect is countered by stress responses that confer tissue damage control and disease tolerance to infection. Here we discuss how the stress response regulated by the transcription factor nuclear factor-erythroid 2-related factor 2 (Nrf2) acts in such a manner. PMID:26551709

  9. Potentially lethal damage repair by total and quiescent tumor cells following various DNA-damaging treatments

    Energy Technology Data Exchange (ETDEWEB)

    Masunaga, Shin-ichiro; Ono, Koji; Suzuki, Minoru; Kinashi, Yuko; Takagaki, Masao [Kyoto Univ., Kumatori, Osaka (Japan). Research Reactor Inst; Hori, Hitoshi; Kasai, Soko; Nagasawa, Hideko; Uto, Yoshihiro

    1999-08-01

    After continuous labeling of proliferating (P) cells with 5-bromo-2'-deoxyuridine (BrdU) for 5 days, SCC VII tumor-bearing mice received various kinds of DNA-damaging treatments: gamma-ray irradiation, tirapazamine (TPZ, hypoxia-specific cytotoxin) administration, or cisplatin injection. From 0.5 to 72 hr after treatment, tumors were excised, minced, and trypsinized. Single tumor cell suspensions were incubated for 48 hr with a cytokinesis-blocker, cytochalasin-B. Then, the micronucleus (MN) frequency for BrdU-unlabeled cells, quiescent (Q) cells at treatment, was determined using immunofluorescence staining for BrdU. The MN frequency for total (P+Q) cells was obtained from tumors that were not pretreated with BrdU labeling. The sensitivity to each DNA-damaging treatment was evaluated in terms of the frequency of induced micronuclei in binuclear tumor cells (MN frequency). Treatment with gamma-rays or cisplatin resulted in a larger MN frequency in total cells than in Q cells. In contrast, TPZ treatment produced a smaller MN frequency in total cells than in Q cells. Regardless of the treatment used, Q cells showed greater repair capacities than total cells. However, TPZ caused much smaller repair capacity in both total and Q cells, compared with gamma-rays or cisplatin. Gamma-rays and cisplatin produced similar repair patterns. Differences in sensitivity between total and Q cells and repair patterns of the two cell populations were thought to depend on differences between the two cell populations in the toxicity of the DNA-damaging treatment and distribution pattern of the anticancer agent. (author)

  10. The 23rd Annual Meeting of the European Tissue Repair Society (ETRS) in Reims, France

    DEFF Research Database (Denmark)

    Von den Hoff, Johannes W; Ågren, Sven Per Magnus; Coulomb, Bernard;

    2014-01-01

    The 23rd Annual Meeting of the European Tissue Repair Society, Reims, France, October 23 to 25, 2013 focused on tissue repair and regenerative medicine covering topics such as stem cells, biomaterials, tissue engineering, and burns.......The 23rd Annual Meeting of the European Tissue Repair Society, Reims, France, October 23 to 25, 2013 focused on tissue repair and regenerative medicine covering topics such as stem cells, biomaterials, tissue engineering, and burns....

  11. Repair of postirradiation damage to colorectum: a progress report

    Energy Technology Data Exchange (ETDEWEB)

    Bricker, E.M.; Johnston, W.D.; Patwardhan, R.V.

    1981-05-01

    The results of 21 operations for repair of rectovaginal fistula and/or stricture secondary to irradiation for pelvic cancer are presented. The operations rely on the use of proximal nonirradiated colon with normal blood supply for effecting the repair. In patients having had a previous colostomy, it is possible to use the proximal end of the bypassed colon for this purpose. There is minimal dissection of the rectal ampulla and the presacral space is never entered. Continuity is established by anastomosis to the anterior rectal wall via an abdominal approach alone, or by a combined abdominovaginal or abdominoperineal approach. It has been found that nonirradiated colon of normal vascularity can be expected to heal to irradiated colon or rectum, thus making the extensive resections associated with correction of these abnormalities unnecessary. The functional result in 18 of 19 patients who underwent this procedure was satisfactory to excellent. One patient had a poor result because of partial rectal incontinence. Two operations out of the 21 were total failures and one of these patients died of complications secondary to irradiation damage to the small intestine. One patient has not yet had final colostomy closure. The results are considered promising enough to warrant continued trial.

  12. Aag DNA glycosylase promotes alkylation-induced tissue damage mediated by Parp1.

    Directory of Open Access Journals (Sweden)

    Jennifer A Calvo

    2013-04-01

    Full Text Available Alkylating agents comprise a major class of front-line cancer chemotherapeutic compounds, and while these agents effectively kill tumor cells, they also damage healthy tissues. Although base excision repair (BER is essential in repairing DNA alkylation damage, under certain conditions, initiation of BER can be detrimental. Here we illustrate that the alkyladenine DNA glycosylase (AAG mediates alkylation-induced tissue damage and whole-animal lethality following exposure to alkylating agents. Aag-dependent tissue damage, as observed in cerebellar granule cells, splenocytes, thymocytes, bone marrow cells, pancreatic β-cells, and retinal photoreceptor cells, was detected in wild-type mice, exacerbated in Aag transgenic mice, and completely suppressed in Aag⁻/⁻ mice. Additional genetic experiments dissected the effects of modulating both BER and Parp1 on alkylation sensitivity in mice and determined that Aag acts upstream of Parp1 in alkylation-induced tissue damage; in fact, cytotoxicity in WT and Aag transgenic mice was abrogated in the absence of Parp1. These results provide in vivo evidence that Aag-initiated BER may play a critical role in determining the side-effects of alkylating agent chemotherapies and that Parp1 plays a crucial role in Aag-mediated tissue damage.

  13. The cellular and molecular mechanisms of tissue repair and regeneration as revealed by studies in Xenopus

    Science.gov (United States)

    Li, Jingjing; Zhang, Siwei

    2016-01-01

    Abstract Survival of any living organism critically depends on its ability to repair and regenerate damaged tissues and/or organs during its lifetime following injury, disease, or aging. Various animal models from invertebrates to vertebrates have been used to investigate the molecular and cellular mechanisms of wound healing and tissue regeneration. It is hoped that such studies will form the framework for identifying novel clinical treatments that will improve the healing and regenerative capacity of humans. Amongst these models, Xenopus stands out as a particularly versatile and powerful system. This review summarizes recent findings using this model, which have provided fundamental knowledge of the mechanisms responsible for efficient and perfect tissue repair and regeneration.

  14. Extracellular Matrices (ECM) for Tissue Repair.

    Science.gov (United States)

    Polanco, Thais O; Xylas, Joanna; Lantis, John C

    2016-04-01

    Persistence of skin wounds due to underlying disease, bacterial contamination, and/or repeated trauma, causes a chronic condition where a functional extracellular matrix (ECM) cannot be established and the normal wound-healing cascade is unable to progress. These open chronic wounds leave the body susceptible to infection and present a major healthcare problem. To this end, a broad range of biologic ECM scaffolds have been developed that can provide other therapeutic options aside from traditional wound care approaches. These tissue engineered ECM scaffolds aim to facilitate the restoration of functional skin-like tissue by altering the chronic wound environment and facilitating cellular attachment, proliferation, and differentiation. This discussion will center on reviewing current ECM scaffolds and highlighting their properties and mechanism of action with respect to the clinical application in chronic, non-healing wounds.

  15. Repair of skin damage during fractionated irradiation with gamma rays and low-LET carbon ions.

    Science.gov (United States)

    Ando, Koichi; Koike, Sachiko; Uzawa, Akiko; Takai, Nobuhiko; Fukawa, Takeshi; Furusawa, Yoshiya; Aoki, Mizuho; Hirayama, Ryoichi

    2006-06-01

    In clinical use of carbon-ion beams, a deep-seated tumor is irradiated with a Spread-Out Bragg peak (SOBP) with a high-LET feature, whereas surface skin is irradiated with an entrance plateau, the LET of which is lower than that of the peak. The repair kinetics of murine skin damage caused by an entrance plateau of carbon ions was compared with that caused by photons using a scheme of daily fractionated doses followed by a top-up dose. Right hind legs received local irradiations with either 20 keV/microm carbon ions or gamma rays. The skin reaction of the irradiated legs was scored every other day up to Day 35 using a scoring scale that consisted of 10 steps, ranging from 0.5 to 5.0. An isoeffect dose to produce a skin reaction score of 3.0 was used to obtain a total dose and a top-up dose for each fractionation. Dependence on a preceding dose and on the time interval of a top-up dose was examined using gamma rays. For fractionated gamma rays, the total dose linearly increased while the top-up dose linearly decreased with an increase in the number of fractions. The magnitude of damage repair depended on the size of dose per fraction, and was larger for 5.2 Gy than 12.5 Gy. The total dose of carbon ions with 5.2 Gy per fraction did not change till 2 fractions, but abruptly increased at the 3rd fraction. Factors such as rapid repopulation, induced repair and cell cycle synchronization are possible explanations for the abrupt increase. As an abrupt increase/decrease of normal tissue damage could be caused by changing the number of fractions in carbon-ion radiotherapy, we conclude that, unlike photon therapy, skin damage should be carefully studied when the number of fractions is changed in new clinical trials.

  16. 49 CFR 192.713 - Transmission lines: Permanent field repair of imperfections and damages.

    Science.gov (United States)

    2010-10-01

    ... Maintenance § 192.713 Transmission lines: Permanent field repair of imperfections and damages. (a) Each imperfection or damage that impairs the serviceability of pipe in a steel transmission line operating at or... 49 Transportation 3 2010-10-01 2010-10-01 false Transmission lines: Permanent field repair...

  17. Role of Rad54, Rad54b and Snm1 in DNA damage repair

    NARCIS (Netherlands)

    J. Wesoly (Joanna)

    2003-01-01

    textabstractThe aim of this thesis is to investigate the function of a number of genes involved in mammalian DNA damage repair, in particular in repair of DNA double-strand breaks (DSBs). Among a large number of different damages that can be introduced to DNA, DSBs are especially toxic. If left unre

  18. Role of Rad54, Rad54b and Snm1 in DNA damage repair

    NARCIS (Netherlands)

    J. Wesoly (Joanna)

    2003-01-01

    textabstractThe aim of this thesis is to investigate the function of a number of genes involved in mammalian DNA damage repair, in particular in repair of DNA double-strand breaks (DSBs). Among a large number of different damages that can be introduced to DNA, DSBs are especially toxic. If

  19. DNA repair pathways in radiation induced cellular damage: a molecular approach

    NARCIS (Netherlands)

    L.R. van Veelen (Lieneke)

    2005-01-01

    markdownabstract__Abstract__ DNA damage, especially double-strand breaks, can be induced by endogenous or exogenous darnaging agents, such as ionizing radiation. Repair of DNA damage is very important in maintaining genomic stability. Incorrect repair may lead to chromosomal aberrations,

  20. DNA repair pathways in radiation induced cellular damage: a molecular approach

    NARCIS (Netherlands)

    L.R. van Veelen (Lieneke)

    2005-01-01

    markdownabstract__Abstract__ DNA damage, especially double-strand breaks, can be induced by endogenous or exogenous darnaging agents, such as ionizing radiation. Repair of DNA damage is very important in maintaining genomic stability. Incorrect repair may lead to chromosomal aberrations, translocat

  1. Mystery of DNA repair: the role of the MRN complex and ATM kinase in DNA damage repair.

    Science.gov (United States)

    Czornak, Kamila; Chughtai, Sanaullah; Chrzanowska, Krystyna H

    2008-01-01

    Genomes are subject to a number of exogenous or endogenous DNA-damaging agents that cause DNA double-strand breaks (DSBs). These critical DNA lesions can result in cell death or a wide variety of genetic alterations, including deletions, translocations, loss of heterozygosity, chromosome loss, or chromosome fusions, which enhance genome instability and can trigger carcinogenesis. The cells have developed an efficient mechanism to cope with DNA damages by evolving the DNA repair machinery. There are 2 major DSB repair mechanisms: nonhomologous end joining (NHEJ) and homologous recombination (HR). One element of the repair machinery is the MRN complex, consisting of MRE11, RAD50 and NBN (previously described as NBS1), which is involved in DNA replication, DNA repair, and signaling to the cell cycle checkpoints. A number of kinases, like ATM (ataxia-telangiectasia mutated), ATR (ataxia-telangiectasia and Rad-3-related), and DNA PKcs (DNA protein kinase catalytic subunit), phosphorylate various protein targets in order to repair the damage. If the damage cannot be repaired, they direct the cell to apoptosis. The MRN complex as well as repair kinases are also involved in telomere maintenance and genome stability. The dysfunction of particular elements involved in the repair mechanisms leads to genome instability disorders, like ataxia telangiectasia (A-T), A-T-like disorder (ATLD) and Nijmegen breakage syndrome (NBS). The mutated genes responsible for these disorders code for proteins that play key roles in the process of DNA repair. Here we present a detailed review of current knowledge on the MRN complex, kinases engaged in DNA repair, and genome instability disorders.

  2. Augmentation of Rotator Cuff Repair With Soft Tissue Scaffolds

    OpenAIRE

    2015-01-01

    Background Tears of the rotator cuff are one of the most common tendon disorders. Treatment often includes surgical repair, but the rate of failure to gain or maintain healing has been reported to be as high as 94%. This has been substantially attributed to the inadequate capacity of tendon to heal once damaged, particularly to bone at the enthesis. A number of strategies have been developed to improve tendon-bone healing, tendon-tendon healing, and tendon regeneration. Scaffolds have receive...

  3. A matter of life or death: modeling DNA damage and repair in bacteria.

    Science.gov (United States)

    Karschau, Jens; de Almeida, Camila; Richard, Morgiane C; Miller, Samantha; Booth, Ian R; Grebogi, Celso; de Moura, Alessandro P S

    2011-02-16

    DNA damage is a hazard all cells must face, and evolution has created a number of mechanisms to repair damaged bases in the chromosome. Paradoxically, many of these repair mechanisms can create double-strand breaks in the DNA molecule which are fatal to the cell. This indicates that the connection between DNA repair and death is far from straightforward, and suggests that the repair mechanisms can be a double-edged sword. In this report, we formulate a mathematical model of the dynamics of DNA damage and repair, and we obtain analytical expressions for the death rate. We predict a counterintuitive relationship between survival and repair. We can discriminate between two phases: below a critical threshold in the number of repair enzymes, the half-life decreases with the number of repair enzymes, but becomes independent of the number of repair enzymes above the threshold. We are able to predict quantitatively the dependence of the death rate on the damage rate and other relevant parameters. We verify our analytical results by simulating the stochastic dynamics of DNA damage and repair. Finally, we also perform an experiment with Escherichia coli cells to test one of the predictions of our model.

  4. Abnormal Base Excision Repair at Trinucleotide Repeats Associated with Diseases: A Tissue-Selective Mechanism

    Directory of Open Access Journals (Sweden)

    Agathi-Vasiliki Goula

    2013-07-01

    Full Text Available More than fifteen genetic diseases, including Huntington’s disease, myotonic dystrophy 1, fragile X syndrome and Friedreich ataxia, are caused by the aberrant expansion of a trinucleotide repeat. The mutation is unstable and further expands in specific cells or tissues with time, which can accelerate disease progression. DNA damage and base excision repair (BER are involved in repeat instability and might contribute to the tissue selectivity of the process. In this review, we will discuss the mechanisms of trinucleotide repeat instability, focusing more specifically on the role of BER.

  5. The Role of Cell Plasticity in Tissue Repair: Adaptive Cellular Reprogramming.

    Science.gov (United States)

    Jessen, Kristjan R; Mirsky, Rhona; Arthur-Farraj, Peter

    2015-09-28

    It is becoming clear that a radical change of cell identity of differentiated cells in vivo, triggered by injury or other adversity, provides an essential route to recovery for many different mammalian tissues. This process, which we term adaptive cellular reprogramming, promotes regeneration in one of two ways: by providing a transient class of repair cells or by directly replacing cells lost during tissue damage. Controlling adaptive changes in cell fate in vivo in order to promote the body's own cell therapy, particularly by pharmacology rather than genetics, is likely to become an increasingly active area of future work. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Recent Advances in Tissue Engineering Strategies for the Treatment of Joint Damage.

    Science.gov (United States)

    Stephenson, Makeda K; Farris, Ashley L; Grayson, Warren L

    2017-08-01

    While the clinical potential of tissue engineering for treating joint damage has yet to be realized, research and commercialization efforts in the field are geared towards overcoming major obstacles to clinical translation, as well as towards achieving engineered grafts that recapitulate the unique structures, function, and physiology of the joint. In this review, we describe recent advances in technologies aimed at obtaining biomaterials, stem cells, and bioreactors that will enable the development of effective tissue-engineered treatments for repairing joint damage. 3D printing of scaffolds is aimed at improving the mechanical structure and microenvironment necessary for bone regeneration within a damaged joint. Advances in our understanding of stem cell biology and cell manufacturing processes are informing translational strategies for the therapeutic use of allogeneic and autologous cells. Finally, bioreactors used in combination with cells and biomaterials are promising strategies for generating large tissue grafts for repairing damaged tissues in pre-clinical models. Together, these advances along with ongoing research directions are making tissue engineering increasingly viable for the treatment of joint damage.

  7. An acidic microenvironment sets the humoral pattern recognition molecule PTX3 in a tissue repair mode.

    Science.gov (United States)

    Doni, Andrea; Musso, Tiziana; Morone, Diego; Bastone, Antonio; Zambelli, Vanessa; Sironi, Marina; Castagnoli, Carlotta; Cambieri, Irene; Stravalaci, Matteo; Pasqualini, Fabio; Laface, Ilaria; Valentino, Sonia; Tartari, Silvia; Ponzetta, Andrea; Maina, Virginia; Barbieri, Silvia S; Tremoli, Elena; Catapano, Alberico L; Norata, Giuseppe D; Bottazzi, Barbara; Garlanda, Cecilia; Mantovani, Alberto

    2015-06-01

    Pentraxin 3 (PTX3) is a fluid-phase pattern recognition molecule and a key component of the humoral arm of innate immunity. In four different models of tissue damage in mice, PTX3 deficiency was associated with increased fibrin deposition and persistence, and thicker clots, followed by increased collagen deposition, when compared with controls. Ptx3-deficient macrophages showed defective pericellular fibrinolysis in vitro. PTX3-bound fibrinogen/fibrin and plasminogen at acidic pH and increased plasmin-mediated fibrinolysis. The second exon-encoded N-terminal domain of PTX3 recapitulated the activity of the intact molecule. Thus, a prototypic component of humoral innate immunity, PTX3, plays a nonredundant role in the orchestration of tissue repair and remodeling. Tissue acidification resulting from metabolic adaptation during tissue repair sets PTX3 in a tissue remodeling and repair mode, suggesting that matrix and microbial recognition are common, ancestral features of the humoral arm of innate immunity. © 2015 Doni et al.

  8. Meniscal repair by fibrocartilage in the dog : Characterization of the repair tissue and the role of vascularity

    NARCIS (Netherlands)

    Veth, RPH; Jansen, HWB; Nielsen, HKL; deGroot, JH; Pennings, AJ; Kuijer, R

    1996-01-01

    Lesions in the avascular part of 20 canine menisci were repaired by implantation of a porous polyurethane. Seven menisci were not repaired and served as controls. The repair tissue was characterized by biochemical and immunological analysis. The role of vascularity in healing was studied by perfusio

  9. Regulation of Ceramide Synthase-Mediated Crypt Epithelium Apoptosis by DNA Damage Repair Enzymes

    Science.gov (United States)

    Rotolo, Jimmy A.; Mesicek, Judith; Maj, Jerzy; Truman, Jean-Philip; Haimovitz-Friedman, Adriana; Kolesnick, Richard; Fuks, Zvi

    2015-01-01

    Acute endothelial cell apoptosis and microvascular compromise couple GI tract irradiation to reproductive death of intestinal crypt stem cell clonogens (SCCs) following high-dose radiation. Genetic or pharmacologic inhibition of endothelial apoptosis prevents intestinal damage, but as the radiation dose is escalated, SCCs become directly susceptible to an alternate cell death mechanism, mediated via ceramide synthase (CS)-stimulated de novo synthesis of the pro-apoptotic sphingolipid ceramide, and p53-independent apoptosis of crypt SCCs. We previously reported that ATM deficiency resets the primary radiation lethal pathway, allowing CS-mediated apoptosis at the low-dose range of radiation. The mechanism for this event, termed target reordering, remains unknown. Here we show that inactivation of DNA damage repair pathways signal CS-mediated apoptosis in crypt SCCs, presumably via persistent unrepaired DNA double strand breaks (DSBs). Genetic loss-of-function of sensors and transducers of DNA DSB repair confers the CS-mediated lethal pathway in intestines of sv129/B6Mre11ATLD1/ATLD1 and C57BL/6Prkdc/SCID (SCID) mice exposed to low-dose radiation. In contrast, CS-mediated SCC lethality was mitigated in irradiated gain-of-function Rad50S/S mice, and epistasis studies order Rad50 upstream of Mre11. These studies suggest unrepaired DNA DSBs as causative in target re-ordering in intestinal SCCs. As such, we provide an in vivo model of DNA damage repair that is standardized, can be exploited to understand allele-specific regulation in intact tissue, and is pharmacologically tractable. PMID:20086180

  10. Repair of sciatic nerve defects using tissue engineered nerves*

    Institute of Scientific and Technical Information of China (English)

    Caishun Zhang; Gang Lv

    2013-01-01

    In this study, we constructed tissue-engineered nerves with acel ular nerve al ografts in Sprague-Dawley rats, which were prepared using chemical detergents-enzymatic digestion and mechanical methods, in combination with bone marrow mesenchymal stem cel s of Wistar rats cultured in vitro, to repair 15 mm sciatic bone defects in Wistar rats. At postoperative 12 weeks, electrophysiological detection results showed that the conduction velocity of regenerated nerve after repair with tis-sue-engineered nerves was similar to that after autologous nerve grafting, and was higher than that after repair with acel ular nerve al ografts. Immunohistochemical staining revealed that motor endplates with acetylcholinesterase-positive nerve fibers were orderly arranged in the middle and superior parts of the gastrocnemius muscle;regenerated nerve tracts and sprouted branches were connected with motor endplates, as shown by acetylcholinesterase histochemistry combined with silver staining. The wet weight ratio of the tibialis anterior muscle at the affected contralateral hind limb was similar to the sciatic nerve after repair with autologous nerve grafts, and higher than that after repair with acel ular nerve al ografts. The hind limb motor function at the affected side was significantly improved, indicating that acel ular nerve al ografts combined with bone marrow me-senchymal stem cel bridging could promote functional recovery of rats with sciatic nerve defects.

  11. Augmentation of Rotator Cuff Repair With Soft Tissue Scaffolds

    Science.gov (United States)

    Thangarajah, Tanujan; Pendegrass, Catherine J.; Shahbazi, Shirin; Lambert, Simon; Alexander, Susan; Blunn, Gordon W.

    2015-01-01

    Background Tears of the rotator cuff are one of the most common tendon disorders. Treatment often includes surgical repair, but the rate of failure to gain or maintain healing has been reported to be as high as 94%. This has been substantially attributed to the inadequate capacity of tendon to heal once damaged, particularly to bone at the enthesis. A number of strategies have been developed to improve tendon-bone healing, tendon-tendon healing, and tendon regeneration. Scaffolds have received considerable attention for replacement, reconstruction, or reinforcement of tendon defects but may not possess situation-specific or durable mechanical and biological characteristics. Purpose To provide an overview of the biology of tendon-bone healing and the current scaffolds used to augment rotator cuff repairs. Study Design Systematic review; Level of evidence, 4. Methods A preliminary literature search of MEDLINE and Embase databases was performed using the terms rotator cuff scaffolds, rotator cuff augmentation, allografts for rotator cuff repair, xenografts for rotator cuff repair, and synthetic grafts for rotator cuff repair. Results The search identified 438 unique articles. Of these, 214 articles were irrelevant to the topic and were therefore excluded. This left a total of 224 studies that were suitable for analysis. Conclusion A number of novel biomaterials have been developed into biologically and mechanically favorable scaffolds. Few clinical trials have examined their effect on tendon-bone healing in well-designed, long-term follow-up studies with appropriate control groups. While there is still considerable work to be done before scaffolds are introduced into routine clinical practice, there does appear to be a clear indication for their use as an interpositional graft for large and massive retracted rotator cuff tears and when repairing a poor-quality degenerative tendon. PMID:26665095

  12. DNA damage by reactive species: Mechanisms, mutation and repair.

    Science.gov (United States)

    Jena, N R

    2012-07-01

    DNA is continuously attacked by reactive species that can affect its structure and function severely. Structural modifications to DNA mainly arise from modifications in its bases that primarily occur due to their exposure to different reactive species. Apart from this, DNA strand break, inter- and intra-strand crosslinks and DNA-protein crosslinks can also affect the structure of DNA significantly. These structural modifications are involved in mutation, cancer and many other diseases. As it has the least oxidation potential among all the DNA bases, guanine is frequently attacked by reactive species, producing a plethora of lethal lesions. Fortunately, living cells are evolved with intelligent enzymes that continuously protect DNA from such damages. This review provides an overview of different guanine lesions formed due to reactions of guanine with different reactive species. Involvement of these lesions in inter- and intra-strand crosslinks, DNA-protein crosslinks and mutagenesis are discussed. How certain enzymes recognize and repair different guanine lesions in DNA are also presented.

  13. DNA damage by reactive species: Mechanisms, mutation and repair

    Indian Academy of Sciences (India)

    N R Jena

    2012-07-01

    DNA is continuously attacked by reactive species that can affect its structure and function severely. Structural modifications to DNA mainly arise from modifications in its bases that primarily occur due to their exposure to different reactive species. Apart from this, DNA strand break, inter- and intra-strand crosslinks and DNA–protein crosslinks can also affect the structure of DNA significantly. These structural modifications are involved in mutation, cancer and many other diseases. As it has the least oxidation potential among all the DNA bases, guanine is frequently attacked by reactive species, producing a plethora of lethal lesions. Fortunately, living cells are evolved with intelligent enzymes that continuously protect DNA from such damages. This review provides an overview of different guanine lesions formed due to reactions of guanine with different reactive species. Involvement of these lesions in inter- and intra-strand crosslinks, DNA–protein crosslinks and mutagenesis are discussed. How certain enzymes recognize and repair different guanine lesions in DNA are also presented.

  14. Repair of osteochondral defects with allogeneic tissue engineered cartilage implants.

    Science.gov (United States)

    Schreiber, R E; Ilten-Kirby, B M; Dunkelman, N S; Symons, K T; Rekettye, L M; Willoughby, J; Ratcliffe, A

    1999-10-01

    The objective of this study was to evaluate the effect of allogeneic tissue engineered cartilage implants on healing of osteochondral defects. Rabbit chondrocytes were cultured in monolayer, then seeded onto biodegradable, three-dimensional polyglycolic acid meshes. Cartilage constructs were cultured hydrodynamically to yield tissue with relatively more (mature) or less (immature) hyalinelike cartilage, as compared with adult rabbit articular cartilage. Osteochondral defects in the patellar grooves of both stifle joints either were left untreated or implanted with allogeneic tissue engineered cartilage. Histologic samples from in and around the defect sites were examined 3, 6, 9, and 12, and 24 months after surgery. By 9 months after surgery, defects sites treated with cartilage implants contained significantly greater amounts of hyalinelike cartilage with high levels of proteoglycan, and had a smooth, nonfibrillated articular surface as compared to untreated defects. In contrast, the repair tissue formed in untreated defects had fibrillated articular surfaces, significant amounts of fibrocartilage, and negligible proteoglycan. These differences between treated and untreated defects persisted through 24 months after surgery. The results of this study suggest that the treatment of osteochondral lesions with allogenic tissue engineered cartilage implants may lead to superior repair tissue than that found in untreated osteochondral lesions.

  15. The Role of Altered Nucleotide Excision Repair and UVB-Induced DNA Damage in Melanomagenesis

    Directory of Open Access Journals (Sweden)

    Timothy Budden

    2013-01-01

    Full Text Available UVB radiation is the most mutagenic component of the UV spectrum that reaches the earth’s surface and causes the development of DNA damage in the form of cyclobutane pyrimidine dimers and 6-4 photoproducts. UV radiation usually results in cellular death, but if left unchecked, it can affect DNA integrity, cell and tissue homeostasis and cause mutations in oncogenes and tumour-suppressor genes. These mutations, if unrepaired, can lead to abnormal cell growth, increasing the risk of cancer development. Epidemiological data strongly associates UV exposure as a major factor in melanoma development, but the exact biological mechanisms involved in this process are yet to be fully elucidated. The nucleotide excision repair (NER pathway is responsible for the repair of UV-induced lesions. Patients with the genetic disorder Xeroderma Pigmentosum have a mutation in one of eight NER genes associated with the XP complementation groups XP-A to XP-G and XP variant (XP-V. XP is characterized by diminished repair capacity, as well as a 1000-fold increase in the incidence of skin cancers, including melanoma. This has suggested a significant role for NER in melanoma development as a result of UVB exposure. This review discusses the current research surrounding UVB radiation and NER capacity and how further investigation of NER could elucidate the role of NER in avoiding UV-induced cellular death resulting in melanomagenesis.

  16. GENETIC AND MOLECULAR ANALYSIS OF DNA DAMAGE REPAIR AND TOLERANCE PATHWAYS.

    Energy Technology Data Exchange (ETDEWEB)

    SUTHERLAND, B.M.

    2001-07-26

    Radiation can damage cellular components, including DNA. Organisms have developed a panoply of means of dealing with DNA damage. Some repair paths have rather narrow substrate specificity (e.g. photolyases), which act on specific pyrimidine photoproducts in a specific type (e.g., DNA) and conformation (double-stranded B conformation) of nucleic acid. Others, for example, nucleotide excision repair, deal with larger classes of damages, in this case bulky adducts in DNA. A detailed discussion of DNA repair mechanisms is beyond the scope of this article, but one can be found in the excellent book of Friedberg et al. [1] for further detail. However, some DNA damages and paths for repair of those damages important for photobiology will be outlined below as a basis for the specific examples of genetic and molecular analysis that will be presented below.

  17. Role of Macrophages in the Repair Process during the Tissue Migrating and Resident Helminth Infections

    Science.gov (United States)

    Faz-López, Berenice

    2016-01-01

    The Th1/Th2/Th17 balance is a fundamental feature in the regulation of the inflammatory microenvironment during helminth infections, and an imbalance in this paradigm greatly contributes to inflammatory disorders. In some cases of helminthiasis, an initial Th1 response could occur during the early phases of infection (acute), followed by a Th2 response that prevails in chronic infections. During the late phase of infection, alternatively activated macrophages (AAMs) are important to counteract the inflammation caused by the Th1/Th17 response and larval migration, limiting damage and repairing the tissue affected. Macrophages are the archetype of phagocytic cells, with the primary role of pathogen destruction and antigen presentation. Nevertheless, other subtypes of macrophages have been described with important roles in tissue repair and immune regulation. These types of macrophages challenge the classical view of macrophages activated by an inflammatory response. The role of these subtypes of macrophages during helminthiasis is a controversial topic in immunoparasitology. Here, we analyze some of the studies regarding the role of AAMs in tissue repair during the tissue migration of helminths. PMID:27648452

  18. Microvesicle shedding and lysosomal repair fulfill divergent cellular needs during the repair of streptolysin O-induced plasmalemmal damage.

    Directory of Open Access Journals (Sweden)

    Alexander P Atanassoff

    Full Text Available Pathogenic bacteria secrete pore-forming toxins that permeabilize the plasma membrane of host cells. Nucleated cells possess protective mechanisms that repair toxin-damaged plasmalemma. Currently two putative repair scenarios are debated: either the isolation of the damaged membrane regions and their subsequent expulsion as microvesicles (shedding or lysosome-dependent repair might allow the cell to rid itself of its toxic cargo and prevent lysis. Here we provide evidence that both mechanisms operate in tandem but fulfill diverse cellular needs. The prevalence of the repair strategy varies between cell types and is guided by the severity and the localization of the initial toxin-induced damage, by the morphology of a cell and, most important, by the incidence of the secondary mechanical damage. The surgically precise action of microvesicle shedding is best suited for the instant elimination of individual toxin pores, whereas lysosomal repair is indispensable for mending of self-inflicted mechanical injuries following initial plasmalemmal permeabilization by bacterial toxins. Our study provides new insights into the functioning of non-immune cellular defenses against bacterial pathogens.

  19. Ionizing radiation-induced DNA damage and its repair in human cells. Final performance report, July 1992--June 1995

    Energy Technology Data Exchange (ETDEWEB)

    Dizdaroglu, M.

    1995-12-31

    The studies of DNA damage in living cells in vitro and in vivo were continued. A variety of systems including cultured mammalian cells, animals, and human tissues were used to conduct these studies. In addition, enzymatic repair of DNA base damage was studied using several DNA glycosylases. To this end, substrate specificities of these enzymes were examined in terms of a large number of base lesions in DNA. In the first phase of the studies, the author sought to introduce improvements to his methodologies for measurement of DNA damage using the technique of gas chromatography/mass spectrometry (GC/MS). In particular, the quantitative measurement of DNA base damage and DNA-protein crosslinks was improved by incorporation of isotope-dilution mass spectrometry into the methodologies. This is one of the most accurate techniques for quantification of organic compounds. Having improved the measurement technique, studies of DNA damage in living cells and DNA repair by repair enzymes were pursued. This report provides a summary of these studies with references to the original work.

  20. Nicotinamide enhances repair of ultraviolet radiation-induced DNA damage in primary melanocytes.

    Science.gov (United States)

    Thompson, Benjamin C; Surjana, Devita; Halliday, Gary M; Damian, Diona L

    2014-07-01

    Cutaneous melanoma is a significant cause of morbidity and mortality. Nicotinamide is a safe, widely available vitamin that reduces the immune suppressive effects of UV, enhances DNA repair in keratinocytes and has shown promise in the chemoprevention of non-melanoma skin cancer. Here, we report the effect of nicotinamide on DNA damage and repair in primary human melanocytes. Nicotinamide significantly enhanced the repair of oxidative DNA damage (8-oxo-7,8-dihydro-2'-deoxyguanosine) and cyclobutane pyrimidine dimers induced by UV exposure. It also enhanced the repair of 8-oxo-7,8-dihydro-2'-deoxyguanosine induced by the culture conditions in unirradiated melanocytes. A significant increase in the percentage of melanocytes undergoing unscheduled but not scheduled DNA synthesis was observed, confirming that nicotinamide enhances DNA repair in human melanocytes. In summary, nicotinamide, by enhancing DNA repair in melanocytes, is a potential agent for the chemoprevention of cutaneous melanoma.

  1. Self-repairing of material damage. Sonsho wo jiko shufuku yokushisuru zairyo

    Energy Technology Data Exchange (ETDEWEB)

    Matsuoka, S. (National Research Inst. for Metals, Tsukuba (Japan))

    1994-07-01

    In order to control the damage like crack or void formed during the use of structural material by the material itself, it is required to self-detect the damage, to self-judge the state of damage, and to self-control or self-repair the damage finally. Based on the parameter of length, the repair and control is classified into the 1mm-scale functional fine wire and thin film utilization type, 1[mu]m-scale microcapsule type, and 1nm-scale trace element utilization type. For the damage repair and control of functional fine wire and thin film utilization type, the damage is repaired and controlled by pasting thin film or by embedding fine wire of functional material, such as shape memory alloy, Ti-Ni, and piezoelectric ceramics PZT (lead zirconate titanate), on the material surface or inside the material. For the damage repair and control of microcapsule type, is illustrated the control mechanism of high temperature fatigue crack propagation by Y2O3 particles dispersed in the Fe-20Cr alloy. Furthermore, the formation mechanism of self-repairing film by the trace element is also illustrated. 13 refs., 5 figs.

  2. Epithelial-mesenchymal transition in tissue repair and fibrosis.

    Science.gov (United States)

    Stone, Rivka C; Pastar, Irena; Ojeh, Nkemcho; Chen, Vivien; Liu, Sophia; Garzon, Karen I; Tomic-Canic, Marjana

    2016-09-01

    The epithelial-mesenchymal transition (EMT) describes the global process by which stationary epithelial cells undergo phenotypic changes, including the loss of cell-cell adhesion and apical-basal polarity, and acquire mesenchymal characteristics that confer migratory capacity. EMT and its converse, MET (mesenchymal-epithelial transition), are integral stages of many physiologic processes and, as such, are tightly coordinated by a host of molecular regulators. Converging lines of evidence have identified EMT as a component of cutaneous wound healing, during which otherwise stationary keratinocytes (the resident skin epithelial cells) migrate across the wound bed to restore the epidermal barrier. Moreover, EMT plays a role in the development of scarring and fibrosis, as the matrix-producing myofibroblasts arise from cells of the epithelial lineage in response to injury but are pathologically sustained instead of undergoing MET or apoptosis. In this review, we summarize the role of EMT in physiologic repair and pathologic fibrosis of tissues and organs. We conclude that further investigation into the contribution of EMT to the faulty repair of fibrotic wounds might identify components of EMT signaling as common therapeutic targets for impaired healing in many tissues. Graphical Abstract Model for injury-triggered EMT activation in physiologic wound repair (left) and fibrotic wound healing (right).

  3. Biodegradable Materials for Bone Repair and Tissue Engineering Applications

    Directory of Open Access Journals (Sweden)

    Zeeshan Sheikh

    2015-08-01

    Full Text Available This review discusses and summarizes the recent developments and advances in the use of biodegradable materials for bone repair purposes. The choice between using degradable and non-degradable devices for orthopedic and maxillofacial applications must be carefully weighed. Traditional biodegradable devices for osteosynthesis have been successful in low or mild load bearing applications. However, continuing research and recent developments in the field of material science has resulted in development of biomaterials with improved strength and mechanical properties. For this purpose, biodegradable materials, including polymers, ceramics and magnesium alloys have attracted much attention for osteologic repair and applications. The next generation of biodegradable materials would benefit from recent knowledge gained regarding cell material interactions, with better control of interfacing between the material and the surrounding bone tissue. The next generations of biodegradable materials for bone repair and regeneration applications require better control of interfacing between the material and the surrounding bone tissue. Also, the mechanical properties and degradation/resorption profiles of these materials require further improvement to broaden their use and achieve better clinical results.

  4. REPAIR TECHNOLOGY OF THE COMPOSITE WING OF A LIGHT PLANE DAMAGED DURING AN AIRCRAFT CRASH

    Directory of Open Access Journals (Sweden)

    Andrzej ŚWIĄTONIOWSKI

    2016-09-01

    Full Text Available The increasing use of composite structures in aircraft constructions has made it necessary to develop repair methods that will restore the component’s original design strength without compromising its structural integrity. In this paper, the complex repair technology of the composite wing of a light plane, which was damaged during an aircraft crash, is described. The applied repair scheme should meet all the original design requirements for the plane structure.

  5. Study on Repaired Earthquake-Damaged Bridge Piers under Seismic Load

    Directory of Open Access Journals (Sweden)

    Jun Deng

    2015-01-01

    Full Text Available The concrete bridge pier damaged during earthquakes need be repaired to meet the design standards. Steel tube as a traditional material or FRP as a novel material has become popular to repair the damaged reinforced concrete (RC bridge piers. In this paper, experimental and finite element (FE studies are employed to analyze the confinement effectiveness of the different repair materials. The FE method was used to calculate the hysteretic behavior of three predamaged circle RC bridge piers repaired with steel tube, basalt fiber reinforced polymer (BFRP, and carbon fiber reinforced polymer (CFRP, respectively. Meanwhile, the repaired predamaged circle concrete bridge piers were tested by pseudo-static cyclic loading to study the seismic behavior and evaluate the confinement effectiveness of the different repair materials and techniques. The FE analysis and experimental results showed that the repaired piers had similar hysteretic curves with the original specimens and all the three repair techniques can restore the seismic performance of the earthquake-damaged piers. Steel tube jacketing can significantly improve the lateral stiffness and peak load of the damaged pier, while the BFRP and CFRP sheets cannot improve these properties due to their thin thickness.

  6. Repair of corrosion-damaged columns using FRP wraps

    Science.gov (United States)

    Baiyasi, Mohamad Imad

    Many bridge columns in Michigan are damaged by chloride contamination resulting in the corrosion of the steel reinforcement, and swelling and spalling of the concrete and use of the bridges is typically continued. This in itself may not be a serious problem since most columns in Michigan are over-designed and the loss of strength is not a significant issue. However, the lack of any method to minimize or prevent corrosion of the steel results in continued deterioration and unsightly columns. Polymer composite (also known as fiber-reinforced polymer or FRP) jackets offer a possible remedy to this problem. They offer a rapid repair technique with the potential to enhance the longterm durability and compression strength of damaged columns due to the confinement that is provided when fibers are oriented in the hoop direction. Fibers oriented in the vertical direction can enhance the bending strength. Experiments were conducted to assess the effects of using FRP wraps with fibers oriented in the hoop direction for rehabilitating corrosion-damaged columns. Issues that were explored are: (1) effect of freeze-thaw and wet-dry cycles on the properties of FRP panels; (2) freeze-thaw durability of concrete square and cylindrical specimens wrapped with glass and carbon FRP and subjected to an internal expansive force; and (3) effect of wrapping on the rate of corrosion in an accelerated corrosion test. The results of the freeze-thaw experiment indicate that freeze-thaw cycles have no statistically significant effect on the compressive strength of glass and carbon wrapped specimens. For round specimens, glass and carbon wraps increased the strength by a factor of about 2.3 and 2.6, respectively. For square specimens, glass and carbon wraps increased the strength by a factor of 1.4--1.5. Freeze-thaw conditioning generally reduced the longitudinal failure strain of wrapped specimens. The square wrapped specimens had lower compressive strength compared to the round specimens, even

  7. Apparatus and method for enhancing tissue repair in mammals

    Science.gov (United States)

    Goodwin, Thomas J. (Inventor); Parker, Clayton R. (Inventor)

    2009-01-01

    An apparatus is introduced for the use of enhancing tissue repair in mammals. The apparatus includes a sleeve; an electrically conductive coil; a sleeve support; an electrical circuit configured to supply the coil with a square wave time varying electrical current sufficient to create approximately 0.05 gauss to 0.5 gauss. When in use, the sleeve of the apparatus is placed on a mammalian body part and the time varying electromagnetic force of from approximately 0.05 gauss to 0.5 gauss is generated on the mammalian body for an extended period of time so that the tissue is encouraged to be regenerated in the mammalian body part at a rate in excess of the normal tissue regeneration rate relative to regeneration without application of the time varying electromagnetic force.

  8. Comparison of the tendon damage caused by four different anchor systems used in transtendon rotator cuff repair.

    Science.gov (United States)

    Zhang, Qing-Song; Liu, Sen; Zhang, Qiuyang; Xue, Yun; Ge, Dongxia; O'Brien, Michael J; Savoie, Felix H; You, Zongbing

    2012-01-01

    Objectives. The objective of this study was to compare the damage to the rotator cuff tendons caused by four different anchor systems. Methods. 20 cadaveric human shoulder joints were used for transtendon insertion of four anchor systems. The Healix Peek, Fastin RC, Bio-Corkscrew Suture, and Healix Transtend anchors were inserted through the tendons using standard transtendon procedures. The areas of tendon damage were measured. Results. The areas of tendon damage (mean ± standard deviation, n = 7) were 29.1 ± 4.3 mm(2) for the Healix Peek anchor, 20.4 ± 2.3 mm(2) for the Fastin RC anchor, 23.4 ± 1.2 mm(2) for the Bio-Corkscrew Suture anchor, 13.7 ± 3.2 mm(2) for the Healix Transtend anchor inserted directly, and 9.1 ± 2.1 mm(2) for the Healix Transtend anchor inserted through the Percannula system (P anchors). Conclusions. In a cadaver transtendon rotator cuff repair model, smaller anchors caused less damage to the tendon tissues. The Healix Transtend implant system caused the least damage to the tendon tissues. Our findings suggest that smaller anchors should be considered when performing transtendon procedures to repair partial rotator cuff tears.

  9. Non-DBS DNA Repair Genes Regulate Radiation-induced Cytogenetic Damage Repair and Cell Cycle Progression

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry H.; Emami, Kamal; Casey, Rachael; Wu, Honglu

    2008-01-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have shown that genes up-regulated by IR may play important roles in DNA damage repair, the relationship between the regulation of gene expression by IR, particularly genes not known for their roles in DSB repair, and its impact on cytogenetic responses has not been systematically studied. In the present study, the expression of 25 genes selected on the basis of their transcriptional changes in response to IR was individually knocked down by transfection with small interfering RNA in human fibroblast cells. The purpose of this study is to identify new roles of these selected genes on regulating DSB repair and cell cycle progression , as measured in the micronuclei formation and chromosome aberration. In response to IR, the formation of MN was significantly increased by suppressed expression of 5 genes: Ku70 in the DSB repair pathway, XPA in the NER pathway, RPA1 in the MMR pathway, and RAD17 and RBBP8 in cell cycle control. Knocked-down expression of 4 genes (MRE11A, RAD51 in the DSB pathway, SESN1, and SUMO1) significantly inhibited cell cycle progression, possibly because of severe impairment of DNA damage repair. Furthermore, loss of XPA, P21, or MLH1 expression resulted in both significantly enhanced cell cycle progression and increased yields of chromosome aberrations, indicating that these gene products modulate both cell cycle control and DNA damage repair. Most of the 11 genes that affected cytogenetic responses are not known to have clear roles influencing DBS repair. Nine of these 11 genes were up-regulated in cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulate the biological consequences after IR.

  10. Non-DBS DNA Repair Genes Regulate Radiation-induced Cytogenetic Damage Repair and Cell Cycle Progression

    Science.gov (United States)

    Zhang, Ye; Rohde, Larry H.; Emami, Kamal; Casey, Rachael; Wu, Honglu

    2008-01-01

    Changes of gene expression profile are one of the most important biological responses in living cells after ionizing radiation (IR) exposure. Although some studies have shown that genes up-regulated by IR may play important roles in DNA damage repair, the relationship between the regulation of gene expression by IR, particularly genes not known for their roles in DSB repair, and its impact on cytogenetic responses has not been systematically studied. In the present study, the expression of 25 genes selected on the basis of their transcriptional changes in response to IR was individually knocked down by transfection with small interfering RNA in human fibroblast cells. The purpose of this study is to identify new roles of these selected genes on regulating DSB repair and cell cycle progression , as measured in the micronuclei formation and chromosome aberration. In response to IR, the formation of MN was significantly increased by suppressed expression of 5 genes: Ku70 in the DSB repair pathway, XPA in the NER pathway, RPA1 in the MMR pathway, and RAD17 and RBBP8 in cell cycle control. Knocked-down expression of 4 genes (MRE11A, RAD51 in the DSB pathway, SESN1, and SUMO1) significantly inhibited cell cycle progression, possibly because of severe impairment of DNA damage repair. Furthermore, loss of XPA, P21, or MLH1 expression resulted in both significantly enhanced cell cycle progression and increased yields of chromosome aberrations, indicating that these gene products modulate both cell cycle control and DNA damage repair. Most of the 11 genes that affected cytogenetic responses are not known to have clear roles influencing DBS repair. Nine of these 11 genes were up-regulated in cells exposed to gamma radiation, suggesting that genes transcriptionally modulated by IR were critical to regulate the biological consequences after IR.

  11. EFSA Panel on Dietetic Products, Nutrition and Allergies (NDA); Scientific Opinion on the substantiation of health claims related to β-hydroxy β-methylbutyrate monohydrate (HMB) alone or in combination with α-ketoisocaproic acid (KIC) and reduction of muscle tissue damage during exercise (ID 1577, , 1584), increase in lean body mass (ID 1579, 1582, 1583), increase in muscle strength (ID 1578, 1583, 1587), increase in endurance performance (ID 1580, 1581), skeletal muscle tissue repair (ID 1586) and faster recovery from muscle fatigue after exercise (ID 1576, 1585) pursuant to Article 13

    DEFF Research Database (Denmark)

    Tetens, Inge

    claims in relation to β-hydroxy β-methylbutyrate monohydrate (HMB) alone or in combination with α-ketoisocaproic acid (KIC) and reduction of muscle tissue damage during exercise, increase in lean body mass, increase in muscle strength, increase in endurance performance, skeletal muscle tissue repair...... and faster recovery from muscle fatigue after exercise. The scientific substantiation is based on the information provided by the Member States in the consolidated list of Article 13 health claims and references that EFSA has received from Member States or directly from stakeholders. The food constituent...

  12. Nucleotide sequence, DNA damage location and protein stoichiometry influence base excision repair outcome at CAG/CTG repeats

    Science.gov (United States)

    Goula, Agathi-Vasiliki; Pearson, Christopher E.; Della Maria, Julie; Trottier, Yvon; Tomkinson, Alan E.; Wilson, David M.; Merienne, Karine

    2012-01-01

    Expansion of CAG/CTG repeats is the underlying cause of >fourteen genetic disorders, including Huntington’s disease (HD) and myotonic dystrophy. The mutational process is ongoing, with increases in repeat size enhancing the toxicity of the expansion in specific tissues. In many repeat diseases the repeats exhibit high instability in the striatum, whereas instability is minimal in the cerebellum. We provide molecular insights as to how base excision repair (BER) protein stoichiometry may contribute to the tissue-selective instability of CAG/CTG repeats by using specific repair assays. Oligonucleotide substrates with an abasic site were mixed with either reconstituted BER protein stoichiometries mimicking the levels present in HD mouse striatum or cerebellum, or with protein extracts prepared from HD mouse striatum or cerebellum. In both cases, repair efficiency at CAG/CTG repeats and at control DNA sequences was markedly reduced under the striatal conditions, likely due to the lower level of APE1, FEN1 and LIG1. Damage located towards the 5’ end of the repeat tract was poorly repaired accumulating incompletely processed intermediates as compared to an AP lesion in the centre or at the 3’ end of the repeats or within a control sequences. Moreover, repair of lesions at the 5’ end of CAG or CTG repeats involved multinucleotide synthesis, particularly under the cerebellar stoichiometry, suggesting that long-patch BER processes lesions at sequences susceptible to hairpin formation. Our results show that BER stoichiometry, nucleotide sequence and DNA damage position modulate repair outcome, and suggest that a suboptimal LP-BER activity promotes CAG/CTG repeat instability. PMID:22497302

  13. Macrophages: supportive cells for tissue repair and regeneration.

    Science.gov (United States)

    Chazaud, Bénédicte

    2014-03-01

    Macrophages, and more broadly inflammation, have been considered for a long time as bad markers of tissue homeostasis. However, if it is indisputable that macrophages are associated with many diseases in a deleterious way, new roles have emerged, showing beneficial properties of macrophages during tissue repair and regeneration. This discrepancy is likely due to the high plasticity of macrophages, which may exhibit a wide range of phenotypes and functions depending on their environment. Therefore, regardless of their role in immunity, macrophages play a myriad of roles in the maintenance and recovery of tissue homeostasis. They take a major part in the resolution of inflammation. They also exert various effects of parenchymal cells, including stem and progenitor cell, of which they regulate the fate. In the present review, few examples from various tissues are presented to illustrate that, beyond their specific properties in a given tissue, common features have been described that sustain a role of macrophages in the recovery and maintenance of tissue homeostasis.

  14. Cytoprotection: Immune and Matrix Modulation of Tissue Repair

    Science.gov (United States)

    2013-04-01

    MD, PhD CONTRACTING ORGANIZATION: Benaroya Research Institute at Virginia Mason, Seattle, WA 98101 REPORT DATE: April 2013 TYPE OF REPORT...March 2010 – 14 March 2013 4. TITLE AND SUBTITLE Cytoprotection: Immune and Matrix Modulation of Tissue Repair 5a. CONTRACT NUMBER 5b. GRANT NUMBER...min) Subject 1 Subject 2 anti-CD3 5ug/ mlM FI phospho-Akt Fix T0 T5 T1 5 T3 0 0 20 40 60 80 100 Time (min) anti-CD3 5ug/ mlM FI phospho-CD3 Fix T0 T5

  15. DNA damage in plant herbarium tissue.

    Directory of Open Access Journals (Sweden)

    Martijn Staats

    Full Text Available 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.

  16. 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. PMID:22163018

  17. DNA Repair and the Accumulation of Oxidatively Damaged DNA Are Affected by Fruit Intake in Mice

    DEFF Research Database (Denmark)

    Croteau, Deborah L; de Souza-Pinto, Nadja C; Harboe, Charlotte

    2010-01-01

    Aging is associated with elevated oxidative stress and DNA damage. To achieve healthy aging, we must begin to understand how diet affects cellular processes. We postulated that fruit-enriched diets might initiate a program of enhanced DNA repair and thereby improve genome integrity. C57Bl/6 J mice...... were fed for 14 weeks a control diet or a diet with 8% peach or nectarine extract. The activities of DNA repair enzymes, the level of DNA damage, and gene expression changes were measured. Our study showed that repair of various oxidative DNA lesions was more efficient in liver extracts derived from......-fed mice. Taken together, these results suggest that an increased intake of fruits might modulate the efficiency of DNA repair, resulting in altered levels of DNA damage....

  18. Experiment K-7-29: Connective Tissue Studies. Part 3; Rodent Tissue Repair: Skeletal Muscle

    Science.gov (United States)

    Stauber, W.; Fritz, V. K.; Burkovskaya, T. E.; Ilyina-Kakueva, E. I.

    1994-01-01

    Myofiber injury-repair was studied in the rat gastrocnemius following a crush injury to the lower leg prior to flight in order to understand if the regenerative responses of muscles are altered by the lack of gravitational forces during Cosmos 2044 flight. After 14 days of flight, the gastrocnemius muscle was removed from the 5 injured flight rodents and various Earth-based treatment groups for comparison. The Earth-based animals consisted of three groups of five rats with injured muscles from a simulated, tail-suspended, and vivarium as well as an uninjured basal group. The gastrocnemius muscle from each was evaluated by histochemical and immunohistochemical techniques to document myofiber, vascular, and connective tissue alterations following injury. In general the repair process was somewhat similar in all injured muscle samples with regard to extracellular matrix organization and myofiber regeneration. Small and large myofibers were present with a newly organized extracellular matrix indicative of myogenesis and muscle regeneration. In the tail-suspended animals, a more complete repair was observed with no enlarged area of non-muscle cells or matrix material visible. In contrast, the muscle samples from the flight animals were less well differentiated with more macrophages and blood vessels in the repair region but small myofibers and proteoglycans, nevertheless, were in their usual configuration. Thus, myofiber repair did vary in muscles from the different groups, but for the most part, resulted in functional muscle tissue.

  19. Experiment K-7-29: Connective Tissue Studies. Part 3; Rodent Tissue Repair: Skeletal Muscle

    Science.gov (United States)

    Stauber, W.; Fritz, V. K.; Burkovskaya, T. E.; Ilyina-Kakueva, E. I.

    1994-01-01

    Myofiber injury-repair was studied in the rat gastrocnemius following a crush injury to the lower leg prior to flight in order to understand if the regenerative responses of muscles are altered by the lack of gravitational forces during Cosmos 2044 flight. After 14 days of flight, the gastrocnemius muscle was removed from the 5 injured flight rodents and various Earth-based treatment groups for comparison. The Earth-based animals consisted of three groups of five rats with injured muscles from a simulated, tail-suspended, and vivarium as well as an uninjured basal group. The gastrocnemius muscle from each was evaluated by histochemical and immunohistochemical techniques to document myofiber, vascular, and connective tissue alterations following injury. In general the repair process was somewhat similar in all injured muscle samples with regard to extracellular matrix organization and myofiber regeneration. Small and large myofibers were present with a newly organized extracellular matrix indicative of myogenesis and muscle regeneration. In the tail-suspended animals, a more complete repair was observed with no enlarged area of non-muscle cells or matrix material visible. In contrast, the muscle samples from the flight animals were less well differentiated with more macrophages and blood vessels in the repair region but small myofibers and proteoglycans, nevertheless, were in their usual configuration. Thus, myofiber repair did vary in muscles from the different groups, but for the most part, resulted in functional muscle tissue.

  20. Rapid repair of severely earthquake-damaged bridge piers with flexural-shear failure mode

    Science.gov (United States)

    Sun, Zhiguo; Wang, Dongsheng; Du, Xiuli; Si, Bingjun

    2011-12-01

    An experimental study was conducted to investigate the feasibility of a proposed rapid repair technique for severely earthquake-damaged bridge piers with flexural-shear failure mode. Six circular pier specimens were first tested to severe damage in flexural-shear mode and repaired using early-strength concrete with high-fluidity and carbon fiber reinforced polymers (CFRP). After about four days, the repaired specimens were tested to failure again. The seismic behavior of the repaired specimens was evaluated and compared to the original specimens. Test results indicate that the proposed repair technique is highly effective. Both shear strength and lateral displacement of the repaired piers increased when compared to the original specimens, and the failure mechanism of the piers shifted from flexural-shear failure to ductile flexural failure. Finally, a simple design model based on the Seible formulation for post-earthquake repair design was compared to the experimental results. It is concluded that the design equation for bridge pier strengthening before an earthquake could be applicable to seismic repairs after an earthquake if the shear strength contribution of the spiral bars in the repaired piers is disregarded and 1.5 times more FRP sheets is provided.

  1. Method of tissue repair using a composite material

    Science.gov (United States)

    Hutchens, Stacy A; Woodward, Jonathan; Evans, Barbara R; O'Neill, Hugh M

    2014-03-18

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  2. Method of tissue repair using a composite material

    Energy Technology Data Exchange (ETDEWEB)

    Hutchens, Stacy A.; Woodward, Jonathan; Evans, Barbara R.; O' Neill, Hugh M.

    2016-03-01

    A composite biocompatible hydrogel material includes a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa. A calcium comprising salt is disposed in at least some of the pores. The porous polymer matrix can comprise cellulose, including bacterial cellulose. The composite can be used as a bone graft material. A method of tissue repair within the body of animals includes the steps of providing a composite biocompatible hydrogel material including a porous polymer matrix, the polymer matrix including a plurality of pores and providing a Young's modulus of at least 10 GPa, and inserting the hydrogel material into cartilage or bone tissue of an animal, wherein the hydrogel material supports cell colonization in vitro for autologous cell seeding.

  3. Monocyte and Macrophage Plasticity in Tissue Repair and Regeneration

    Science.gov (United States)

    Das, Amitava; Sinha, Mithun; Datta, Soma; Abas, Motaz; Chaffee, Scott; Sen, Chandan K.; Roy, Sashwati

    2016-01-01

    Heterogeneity and high versatility are the characteristic features of the cells of monocyte-macrophage lineage. The mononuclear phagocyte system, derived from the bone marrow progenitor cells, is primarily composed of monocytes, macrophages, and dendritic cells. In regenerative tissues, a central role of monocyte-derived macrophages and paracrine factors secreted by these cells is indisputable. Macrophages are highly plastic cells. On the basis of environmental cues and molecular mediators, these cells differentiate to proinflammatory type I macrophage (M1) or anti-inflammatory or proreparative type II macrophage (M2) phenotypes and transdifferentiate into other cell types. Given a central role in tissue repair and regeneration, the review focuses on the heterogeneity of monocytes and macrophages with current known mechanisms of differentiation and plasticity, including microenvironmental cues and molecular mediators, such as noncoding RNAs. PMID:26118749

  4. Cell-based and biomaterial approaches to connective tissue repair

    Science.gov (United States)

    Stalling, Simone Suzette

    Connective tissue injuries of skin, tendon and ligament, heal by a reparative process in adults, filling the wound site with fibrotic, disorganized scar tissue that poorly reflects normal tissue architecture or function. Conversely, fetal skin and tendon have been shown to heal scarlessly. Complete regeneration is not intrinsically ubiquitous to all fetal tissues; fetal diaphragmatic and gastrointestinal injuries form scars. In vivo studies suggest that the presence of fetal fibroblasts is essential for scarless healing. In the orthopaedic setting, adult anterior cruciate ligament (ACL) heals poorly; however, little is known about the regenerative capacity of fetal ACL or fetal ACL fibroblasts. We characterized in vitro wound healing properties of fetal and adult ACL fibroblasts demonstrating that fetal ACL fibroblasts migrate faster and elaborate greater quantities of type I collagen, suggesting the healing potential of the fetal ACL may not be intrinsically poor. Similar to fetal ACL fibroblasts, fetal dermal fibroblasts also exhibit robust cellular properties. We investigated the age-dependent effects of dermal fibroblasts on tendon-to-bone healing in rat supraspinatus tendon injuries, a reparative injury model. We hypothesized delivery of fetal dermal fibroblasts would increase tissue organization and mechanical properties in comparison to adult dermal fibroblasts. However, at 1 and 8 weeks, the presence of dermal fibroblasts, either adult or fetal, had no significant effect on tissue histology or mechanical properties. There was a decreasing trend in cross-sectional area of repaired tendons treated with fetal dermal fibroblasts in comparison to adult, but this finding was not significant in comparison to controls. Finally, we synthesized a novel polysaccharide, methacrylated methylcellulose (MA-MC), and fabricated hydrogels using a well-established photopolymerization technique. We characterized the physical and mechanical properties of MA-MC hydrogels in

  5. Soft tissue damage after minimally invasive THA

    NARCIS (Netherlands)

    van Oldenrijk, J.; Hoogland, P.V.J.M.; Tuijthof, G.J.M.; Corveleijn, R.; Noordenbos, T.W.H.; Schafroth, M.U.

    2010-01-01

    Methods 5 surgeons each performed a total hip arthroplasty on 5 fresh frozen cadaver hips, using either a MIS anterior, MIS anterolateral, MIS 2-incision, MIS posterior, or lateral transgluteal approach. Postoperatively, the hips were dissected and muscle damage color-stained. We measured proportion

  6. DNA damage in plant herbarium tissue.

    NARCIS (Netherlands)

    Staats, M.; Cuenca, A.; Richardson, J.E.; Ginkel, R.V.; Petersen, G.; Seberg, O.; Bakker, F.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 amplif

  7. Soft tissue damage after minimally invasive THA

    NARCIS (Netherlands)

    van Oldenrijk, J.; Hoogland, P.V.J.M.; Tuijthof, G.J.M.; Corveleijn, R.; Noordenbos, T.W.H.; Schafroth, M.U.

    2010-01-01

    Methods 5 surgeons each performed a total hip arthroplasty on 5 fresh frozen cadaver hips, using either a MIS anterior, MIS anterolateral, MIS 2-incision, MIS posterior, or lateral transgluteal approach. Postoperatively, the hips were dissected and muscle damage color-stained. We measured proportion

  8. Fibroblast growth factors as tissue repair and regeneration therapeutics

    Directory of Open Access Journals (Sweden)

    Quentin M. Nunes

    2016-01-01

    Full Text Available Cell communication is central to the integration of cell function required for the development and homeostasis of multicellular animals. Proteins are an important currency of cell communication, acting locally (auto-, juxta-, or paracrine or systemically (endocrine. The fibroblast growth factor (FGF family contributes to the regulation of virtually all aspects of development and organogenesis, and after birth to tissue maintenance, as well as particular aspects of organism physiology. In the West, oncology has been the focus of translation of FGF research, whereas in China and to an extent Japan a major focus has been to use FGFs in repair and regeneration settings. These differences have their roots in research history and aims. The Chinese drive into biotechnology and the delivery of engineered clinical grade FGFs by a major Chinese research group were important enablers in this respect. The Chinese language clinical literature is not widely accessible. To put this into context, we provide the essential molecular and functional background to the FGF communication system covering FGF ligands, the heparan sulfate and Klotho co-receptors and FGF receptor (FGFR tyrosine kinases. We then summarise a selection of clinical reports that demonstrate the efficacy of engineered recombinant FGF ligands in treating a wide range of conditions that require tissue repair/regeneration. Alongside, the functional reasons why application of exogenous FGF ligands does not lead to cancers are described. Together, this highlights that the FGF ligands represent a major opportunity for clinical translation that has been largely overlooked in the West.

  9. Tissue engineering for articular cartilage repair – the state of the art

    Directory of Open Access Journals (Sweden)

    B Johnstone

    2013-05-01

    Full Text Available Articular cartilage exhibits little capacity for intrinsic repair, and thus even minor injuries or lesions may lead to progressive damage and osteoarthritic joint degeneration, resulting in significant pain and disability. While there have been numerous attempts to develop tissue-engineered grafts or patches to repair focal chondral and osteochondral defects, there remain significant challenges in the clinical application of cell-based therapies for cartilage repair. This paper reviews the current state of cartilage tissue engineering with respect to different cell sources and their potential genetic modification, biomaterial scaffolds and growth factors, as well as preclinical testing in various animal models. This is not intended as a systematic review, rather an opinion of where the field is moving in light of current literature. While significant advances have been made in recent years, the complexity of this problem suggests that a multidisciplinary approach – combining a clinical perspective with expertise in cell biology, biomechanics, biomaterials science and high-throughput analysis will likely be necessary to address the challenge of developing functional cartilage replacements. With this approach we are more likely to realise the clinical goal of treating both focal defects and even large-scale osteoarthritic degenerative changes in the joint.

  10. Tissue engineering for articular cartilage repair--the state of the art.

    Science.gov (United States)

    Johnstone, Brian; Alini, Mauro; Cucchiarini, Magali; Dodge, George R; Eglin, David; Guilak, Farshid; Madry, Henning; Mata, Alvaro; Mauck, Robert L; Semino, Carlos E; Stoddart, Martin J

    2013-05-02

    Articular cartilage exhibits little capacity for intrinsic repair, and thus even minor injuries or lesions may lead to progressive damage and osteoarthritic joint degeneration, resulting in significant pain and disability. While there have been numerous attempts to develop tissue-engineered grafts or patches to repair focal chondral and osteochondral defects, there remain significant challenges in the clinical application of cell-based therapies for cartilage repair. This paper reviews the current state of cartilage tissue engineering with respect to different cell sources and their potential genetic modification, biomaterial scaffolds and growth factors, as well as preclinical testing in various animal models. This is not intended as a systematic review, rather an opinion of where the field is moving in light of current literature. While significant advances have been made in recent years, the complexity of this problem suggests that a multidisciplinary approach - combining a clinical perspective with expertise in cell biology, biomechanics, biomaterials science and high-throughput analysis will likely be necessary to address the challenge of developing functional cartilage replacements. With this approach we are more likely to realise the clinical goal of treating both focal defects and even large-scale osteoarthritic degenerative changes in the joint.

  11. DNA repair decline during mouse spermiogenesis results in the accumulation of heritable DNA damage

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Marchetti, Francesco; Wryobek, Andrew J

    2008-02-21

    The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7- 1 dbf). Analysis of chromosomalaberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a linear response for both single and repeated exposures. These findings show that the differential DNA repair capacity of post-meioitic male germ cells has a major impact on the risk of paternally transmitted heritable damage and suggest that chronic exposures that may occur in the weeks prior to fertilization because of occupational or lifestyle factors (i.e, smoking) can lead to an accumulation of genetic damage in sperm and result in heritable chromosomal aberrations of paternal origin.

  12. DNA Repair Decline During Mouse Spermiogenesis Results in the Accumulation of Heritable DNA Damage

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Marchetti, Francesco; Wyrobek, Andrew J.

    2007-12-01

    The post-meiotic phase of mouse spermatogenesis (spermiogenesis) is very sensitive to the genomic effects of environmental mutagens because as male germ cells form mature sperm they progressively lose the ability to repair DNA damage. We hypothesized that repeated exposures to mutagens during this repair-deficient phase result in the accumulation of heritable genomic damage in mouse sperm that leads to chromosomal aberrations in zygotes after fertilization. We used a combination of single or fractionated exposures to diepoxybutane (DEB), a component of tobacco smoke, to investigate how differential DNA repair efficiencies during the three weeks of spermiogenesis affected the accumulation of DEB-induced heritable damage in early spermatids (21-15 days before fertilization, dbf), late spermatids (14-8 dbf) and sperm (7-1 dbf). Analysis of chromosomal aberrations in zygotic metaphases using PAINT/DAPI showed that late spermatids and sperm are unable to repair DEB-induced DNA damage as demonstrated by significant increases (P<0.001) in the frequencies of zygotes with chromosomal aberrations. Comparisons between single and fractionated exposures suggested that the DNA repair-deficient window during late spermiogenesis may be less than two weeks in the mouse and that during this repair-deficient window there is accumulation of DNA damage in sperm. Finally, the dose-response study in sperm indicated a linear response for both single and repeated exposures. These findings show that the differential DNA repair capacity of post-meioitic male germ cells has a major impact on the risk of paternally transmitted heritable damage and suggest that chronic exposures that may occur in the weeks prior to fertilization because of occupational or lifestyle factors (i.e, smoking) can lead to an accumulation of genetic damage in sperm and result in heritable chromosomal aberrations of paternal origin.

  13. Pulp and periodontal tissue repair - regeneration or tissue metaplasia after dental trauma. A review.

    Science.gov (United States)

    Andreasen, Jens O

    2012-02-01

    Healing subsequent to dental trauma is known to be very complex, a result explained by the variability of the types of dental trauma (six luxations, nine fracture types, and their combinations). On top of that, at least 16 different cellular systems get involved in more severe trauma types each of them with a different potential for healing with repair, i.e. (re-establishment of tissue continuity without functional restitution) and regeneration (where the injured or lost tissue is replaced with new tissue with identical tissue anatomy and function) and finally metaplasia (where a new type of tissue replaces the injured). In this study, a review is given of the impact of trauma to various dental tissues such as alveolar bone, periodontal ligament, cementum, Hertvigs epithelial root sheath, and the pulp.

  14. Pulp and periodontal tissue repair - regeneration or tissue metaplasia after dental trauma. A review

    DEFF Research Database (Denmark)

    Andreasen, Jens O

    2012-01-01

    Healing subsequent to dental trauma is known to be very complex, a result explained by the variability of the types of dental trauma (six luxations, nine fracture types, and their combinations). On top of that, at least 16 different cellular systems get involved in more severe trauma types each o...... of tissue replaces the injured). In this study, a review is given of the impact of trauma to various dental tissues such as alveolar bone, periodontal ligament, cementum, Hertvigs epithelial root sheath, and the pulp....... of them with a different potential for healing with repair, i.e. (re-establishment of tissue continuity without functional restitution) and regeneration (where the injured or lost tissue is replaced with new tissue with identical tissue anatomy and function) and finally metaplasia (where a new type...

  15. Roles of microglia in brain development, tissue maintenance and repair.

    Science.gov (United States)

    Michell-Robinson, Mackenzie A; Touil, Hanane; Healy, Luke M; Owen, David R; Durafourt, Bryce A; Bar-Or, Amit; Antel, Jack P; Moore, Craig S

    2015-05-01

    The emerging roles of microglia are currently being investigated in the healthy and diseased brain with a growing interest in their diverse functions. In recent years, it has been demonstrated that microglia are not only immunocentric, but also neurobiological and can impact neural development and the maintenance of neuronal cell function in both healthy and pathological contexts. In the disease context, there is widespread consensus that microglia are dynamic cells with a potential to contribute to both central nervous system damage and repair. Indeed, a number of studies have found that microenvironmental conditions can selectively modify unique microglia phenotypes and functions. One novel mechanism that has garnered interest involves the regulation of microglial function by microRNAs, which has therapeutic implications such as enhancing microglia-mediated suppression of brain injury and promoting repair following inflammatory injury. Furthermore, recently published articles have identified molecular signatures of myeloid cells, suggesting that microglia are a distinct cell population compared to other cells of myeloid lineage that access the central nervous system under pathological conditions. Thus, new opportunities exist to help distinguish microglia in the brain and permit the study of their unique functions in health and disease. © The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  16. Current hydrogel solutions for repairing and regeneration of complex tissues.

    Science.gov (United States)

    Wang, Y; Cai, Li-Quan; Nugraha, B; Gao, Y; Leo, H L

    2014-01-01

    Hydrogel system, as one of the most important biomaterials, is widely studied because of its tremendous potential in regenerative medicine conferred by its wide range of malleable biochemical and physical characteristics, which include its biocompatibility with the elemental biomolecules in vital tissues, its high water retention capability and adjustable soft-tissue-like physicochemical properties. These properties are modifiable to facilitate the targeted tissue protected from external damaging disturbance and having the encapsulated cells' physiology-functional phenotypes induced or maintained in situ. Recently, hydrogels are increasingly used in the R&D of regenerative medicine to build complex tissue. Most of the insightful work focuses on how to select and fabricate the hydrogel models with desired physicochemical properties, flexibility of auto response to various bio-stimuli, and capability of efficiently forming the complex tissue-mimicking construct at different scales. The present review introduced the major types of hydrogeis, the desirable physicochemical properties, the current fabrication methodologies and special organ-based cases of applications of hydrogels, which are used in complex tissue engineering. In addition, this review also discussed the major hurdles faced by the R&D of hydrogel systems for complex tissue medicine.

  17. Reduced Activity of Double-Strand Break Repair Genes in Prostate Cancer Patients With Late Normal Tissue Radiation Toxicity

    Energy Technology Data Exchange (ETDEWEB)

    Oorschot, Bregje van, E-mail: b.vanoorschot@amc.uva.nl [Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Molecular Medicine (CEMM), Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Hovingh, Suzanne E. [Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Molecular Medicine (CEMM), Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Moerland, Perry D. [Bioinformatics Laboratory, Department of Clinical Epidemiology, Biostatistics and Bioinformatics, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Medema, Jan Paul; Stalpers, Lukas J.A. [Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Molecular Medicine (CEMM), Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands); Vrieling, Harry [Department of Toxicogenetics, Leiden University Medical Center, Leiden (Netherlands); Franken, Nicolaas A.P. [Laboratory for Experimental Oncology and Radiobiology (LEXOR), Center for Molecular Medicine (CEMM), Department of Radiation Oncology, Academic Medical Center, University of Amsterdam, Amsterdam (Netherlands)

    2014-03-01

    Purpose: To investigate clinical parameters and DNA damage response as possible risk factors for radiation toxicity in the setting of prostate cancer. Methods and Materials: Clinical parameters of 61 prostate cancer patients, 34 with (overresponding, OR) and 27 without (non-responding, NR) severe late radiation toxicity were assembled. In addition, for a matched subset the DNA damage repair kinetics (γ-H2AX assay) and expression profiles of DNA repair genes were determined in ex vivo irradiated lymphocytes. Results: Examination of clinical data indicated none of the considered clinical parameters to be correlated with the susceptibility of patients to develop late radiation toxicity. Although frequencies of γ-H2AX foci induced immediately after irradiation were similar (P=.32), significantly higher numbers of γ-H2AX foci were found 24 hours after irradiation in OR compared with NR patients (P=.03). Patient-specific γ-H2AX foci decay ratios were significantly higher in NR patients than in OR patients (P<.0001). Consequently, NR patients seem to repair DNA double-strand breaks (DSBs) more efficiently than OR patients. Moreover, gene expression analysis indicated several genes of the homologous recombination pathway to be stronger induced in NR compared with OR patients (P<.05). A similar trend was observed in genes of the nonhomologous end-joining repair pathway (P=.09). This is congruent with more proficient repair of DNA DSBs in patients without late radiation toxicity. Conclusions: Both gene expression profiling and DNA DSB repair kinetics data imply that less-efficient repair of radiation-induced DSBs may contribute to the development of late normal tissue damage. Induction levels of DSB repair genes (eg, RAD51) may potentially be used to assess the risk for late radiation toxicity.

  18. Continuum theory of fibrous tissue damage mechanics using bond kinetics: application to cartilage tissue engineering.

    Science.gov (United States)

    Nims, Robert J; Durney, Krista M; Cigan, Alexander D; Dusséaux, Antoine; Hung, Clark T; Ateshian, Gerard A

    2016-02-06

    This study presents a damage mechanics framework that employs observable state variables to describe damage in isotropic or anisotropic fibrous tissues. In this mixture theory framework, damage is tracked by the mass fraction of bonds that have broken. Anisotropic damage is subsumed in the assumption that multiple bond species may coexist in a material, each having its own damage behaviour. This approach recovers the classical damage mechanics formulation for isotropic materials, but does not appeal to a tensorial damage measure for anisotropic materials. In contrast with the classical approach, the use of observable state variables for damage allows direct comparison of model predictions to experimental damage measures, such as biochemical assays or Raman spectroscopy. Investigations of damage in discrete fibre distributions demonstrate that the resilience to damage increases with the number of fibre bundles; idealizing fibrous tissues using continuous fibre distribution models precludes the modelling of damage. This damage framework was used to test and validate the hypothesis that growth of cartilage constructs can lead to damage of the synthesized collagen matrix due to excessive swelling caused by synthesized glycosaminoglycans. Therefore, alternative strategies must be implemented in tissue engineering studies to prevent collagen damage during the growth process.

  19. Improved repair of bone defects with prevascularized tissue-engineered bones constructed in a perfusion bioreactor.

    Science.gov (United States)

    Li, De-Qiang; Li, Ming; Liu, Pei-Lai; Zhang, Yuan-Kai; Lu, Jian-Xi; Li, Jian-Min

    2014-10-01

    Vascularization of tissue-engineered bones is critical to achieving satisfactory repair of bone defects. The authors investigated the use of prevascularized tissue-engineered bone for repairing bone defects. The new bone was greater in the prevascularized group than in the non-vascularized group, indicating that prevascularized tissue-engineered bone improves the repair of bone defects. [Orthopedics. 2014; 37(10):685-690.].

  20. Damage induced by continued corrosion in concrete repair systems

    NARCIS (Netherlands)

    Luckovic, M.; Savija, B.; Schlangen, E.

    2014-01-01

    Corrosion of steel reinforcement is the main cause of deterioration in reinforced concrete structures. After the repair, corrosion of the steel might continue and even accelerate. While the development of the corrosion cell depends on many parameters and is difficult to control, the occurrence of vi

  1. MOF and H4 K16 Acetylation Play Important Roles in DNA Damage Repair by Modulating Recruitment of DNA Damage Repair Protein Mdc1 ▿

    Science.gov (United States)

    Li, Xiangzhi; Corsa, Callie Ann Sprunger; Pan, Patricia W.; Wu, Lipeng; Ferguson, David; Yu, Xiaochun; Min, Jinrong; Dou, Yali

    2010-01-01

    MOF (MYST1) is the major enzyme to catalyze acetylation of histone H4 lysine 16 (K16) and is highly conserved through evolution. Using a conditional knockout mouse model and the derived mouse embryonic fibroblast cell lines, we showed that loss of Mof led to a global reduction of H4 K16 acetylation, severe G2/M cell cycle arrest, massive chromosome aberration, and defects in ionizing radiation-induced DNA damage repair. We further showed that although early DNA damage sensing and signaling by ATM were normal in Mof-null cells, the recruitment of repair mediator protein Mdc1 and its downstream signaling proteins 53bp1 and Brca1 to DNA damage foci was completely abolished. Mechanistic studies suggested that Mof-mediated H4 K16 acetylation and an intact acidic pocket on H2A.X were essential for the recruitment of Mdc1. Removal of Mof and its associated proteins phenocopied a charge-neutralizing mutant of H2A.X. Given the well-characterized H4-H2A trans interactions in regulating higher-order chromatin structure, our study revealed a novel chromatin-based mechanism that regulates the DNA damage repair process. PMID:20837706

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

    Science.gov (United States)

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

    2013-01-01

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

  3. 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-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.

  4. Cell and gene therapy for arrhythmias: Repair of cardiac conduction damage

    Institute of Scientific and Technical Information of China (English)

    Yong-Fu Xiao

    2011-01-01

    Action potentials generated in the sinoatrial node(SAN)dominate the rhythm and rate of a healthy human heart.Subsequently,these action potentials propagate to the whole heart via its conduction system .Abnormalities of impulse generation and/or propagation in a heart can cause arrhythmias.For example,SAN dysfunction or conduction block of the atrioventricular node can lead to serious bradycardia which is currently treated with an implanted electronic pacemaker.On the other hand conduction damage may cause reentrant tachyarrhythmias which are primarily treated pharmacologically or by medical device-based therapies,including defibrillation and tissue ablation.However,drug therapies sometimes may not be effective or are associated with serious side effects.Device-based therapies for cardiac arrhythmias,even with well developed technology,still face inadequacies,limitations,hardware complications,and other challenges.Therefore,scientists are actively seeking other alternatives for antiarrhythmic therapy.In particular,cells and genes used for repairing cardiac conduction damage/defect have been investigated in various studies both in vitro and in vivo.Despite the complexities of the excitation and conduction systems of the heart,cell and gene-based strategies provide novel alternatives for treatment or cure of cardiac anhythmias.This review summarizes some highlights of recent research progress in this field.

  5. Peripheral endothelial cell damage after trephination of donor tissue.

    Science.gov (United States)

    Terry, Mark A; Saad, Hisham A; Shamie, Neda; Shah, Anand K

    2009-12-01

    To evaluate and quantify the degree and pattern of donor endothelial cell damage, which occurs with mechanical trephination of donor corneal tissue. Twenty donor corneal-scleral tissues were used for these paired experiments. The tissues were randomized for trephination with 10 tissues trephinated by an 8.0-mm-diameter Barron trephine (Katena, Denville, NJ), and 10 tissues trephinated with an 8.0-mm-diameter UltraFit Coronet trephine (distributed by Angiotech, British Columbia, Canada) by the same investigator. Trephinated corneal buttons were then stained with vital dye stain, and the endothelial layer image captured with digital photography. The images were then analyzed by digital planimetry, and the pattern and quantity of endothelial damage was determined by an investigator who was masked to the specific trephine used for the individual tissue. Trephination created a pattern of circular damage at the edge of the donor button in every case with no break in continuity of the circle, but some portions of the circle were wider than others. Occasional, scattered, peripheral small areas also displayed damage, but no significant striae, stretch, or other central damage was noted in any donor. The mean percent damage in the series was 6.35% +/- 0.90% (range: 4.33%-7.78%). The UltraFit Coronet trephinations averaged damage of 5.64% +/- 0.85% (range: 4.33%-6.69%), and the Barron trephinations averaged damage of 6.50% +/- 0.95% (range: 4.92%-7.78%). Although 8 of 10 experimental pairs of trephinations demonstrated less peripheral endothelial damage with the UltraFit Coronet trephine, the mean damage between each group did not reach statistical significance in this small series. (P = 0.08) Donor mechanical trephination of full-thickness corneal tissue creates relatively consistent amounts of peripheral edge damage and likely no central endothelial damage. There may exist differences in edge damage between different mechanical trephination systems, and a direct comparison

  6. Mesenchymal stem cell therapy in osteoarthritis: advanced tissue repair or intervention with smouldering synovial activation?

    Science.gov (United States)

    van Lent, Peter L E M; van den Berg, Wim B

    2013-03-20

    Although it is generally accepted that osteoarthritis is a degenerative condition of the cartilage, other tissues such as synovium in which immunological and inflammatory reactions occur contribute to the development of joint pathology. This sheds new light on the potential mechanism of action of mesenchymal stem cell therapy in osteoarthritis. Rather than tissue repair due to local transformation of injected mesenchymal stem cells to chondrocytes and filling defects in cartilage, such treatment might suppress synovial activation and indirectly ameliorate cartilage damage. Desando and co-workers report in Arthritis Research & Therapy that intra-articular delivery of adipose-derived stem cells attenuates progression of synovial activation and joint destruction in osteoarthritis in an experimental rabbit model. Clinical studies are warranted to see whether this approach might be a novel way to combat development of joint destruction in inflammatory subtypes of osteoarthritis.

  7. Living with cracks: Damage and repair in human bone

    Science.gov (United States)

    Taylor, David; Hazenberg, Jan G.; Lee, T. Clive

    2007-04-01

    Our bones are full of cracks, which form and grow as a result of daily loading activities. Bone is the major structural material in our bodies. Although weaker than many engineering materials, it has one trick that keeps it ahead - it can repair itself. Small cracks, which grow under cyclic stresses by the mechanism of fatigue, can be detected and removed before they become long enough to be dangerous. This article reviews the work that has been done to understand how cracks form and grow in bone, and how they can be detected and repaired in a timely manner. This is truly an interdisciplinary research field, requiring the close cooperation of materials scientists, biologists and engineers.

  8. Autophagy, Innate Immunity and Tissue Repair in Acute Kidney Injury

    Directory of Open Access Journals (Sweden)

    Pu Duann

    2016-05-01

    Full Text Available Kidney is a vital organ with high energy demands to actively maintain plasma hemodynamics, electrolytes and water homeostasis. Among the nephron segments, the renal tubular epithelium is endowed with high mitochondria density for their function in active transport. Acute kidney injury (AKI is an important clinical syndrome and a global public health issue with high mortality rate and socioeconomic burden due to lack of effective therapy. AKI results in acute cell death and necrosis of renal tubule epithelial cells accompanied with leakage of tubular fluid and inflammation. The inflammatory immune response triggered by the tubular cell death, mitochondrial damage, associative oxidative stress, and the release of many tissue damage factors have been identified as key elements driving the pathophysiology of AKI. Autophagy, the cellular mechanism that removes damaged organelles via lysosome-mediated degradation, had been proposed to be renoprotective. An in-depth understanding of the intricate interplay between autophagy and innate immune response, and their roles in AKI pathology could lead to novel therapies in AKI. This review addresses the current pathophysiology of AKI in aspects of mitochondrial dysfunction, innate immunity, and molecular mechanisms of autophagy. Recent advances in renal tissue regeneration and potential therapeutic interventions are also discussed.

  9. Estimating the effect of human base excision repair protein variants on the repair of oxidative DNA base damage.

    Science.gov (United States)

    Sokhansanj, Bahrad A; Wilson, David M

    2006-05-01

    Epidemiologic studies have revealed a complex association between human genetic variance and cancer risk. Quantitative biological modeling based on experimental data can play a critical role in interpreting the effect of genetic variation on biochemical pathways relevant to cancer development and progression. Defects in human DNA base excision repair (BER) proteins can reduce cellular tolerance to oxidative DNA base damage caused by endogenous and exogenous sources, such as exposure to toxins and ionizing radiation. If not repaired, DNA base damage leads to cell dysfunction and mutagenesis, consequently leading to cancer, disease, and aging. Population screens have identified numerous single-nucleotide polymorphism variants in many BER proteins and some have been purified and found to exhibit mild kinetic defects. Epidemiologic studies have led to conflicting conclusions on the association between single-nucleotide polymorphism variants in BER proteins and cancer risk. Using experimental data for cellular concentration and the kinetics of normal and variant BER proteins, we apply a previously developed and tested human BER pathway model to (i) estimate the effect of mild variants on BER of abasic sites and 8-oxoguanine, a prominent oxidative DNA base modification, (ii) identify ranges of variation associated with substantial BER capacity loss, and (iii) reveal nonintuitive consequences of multiple simultaneous variants. Our findings support previous work suggesting that mild BER variants have a minimal effect on pathway capacity whereas more severe defects and simultaneous variation in several BER proteins can lead to inefficient repair and potentially deleterious consequences of cellular damage.

  10. The Cartography of UV-induced DNA Damage Formation and DNA Repair.

    Science.gov (United States)

    Hu, Jinchuan; Adar, Sheera

    2017-01-01

    DNA damage presents a barrier to DNA-templated biochemical processes, including gene expression and faithful DNA replication. Compromised DNA repair leads to mutations, enhancing the risk for genetic diseases and cancer development. Conventional experimental approaches to study DNA damage required a researcher to choose between measuring bulk damage over the entire genome, with little or no resolution regarding a specific location, and obtaining data specific to a locus of interest, without a global perspective. Recent advances in high-throughput genomic tools overcame these limitations and provide high-resolution measurements simultaneously across the genome. In this review, we discuss the available methods for measuring DNA damage and their repair, focusing on genomewide assays for pyrimidine photodimers, the major types of damage induced by ultraviolet irradiation. These new genomic assays will be a powerful tool in identifying key components of genome stability and carcinogenesis. © 2016 The American Society of Photobiology.

  11. Comparative DNA Damage and Repair in Echinoderm Coelomocytes Exposed to Genotoxicants

    OpenAIRE

    El-Bibany, Ameena H.; Bodnar, Andrea G.; Reinardy, Helena C.

    2014-01-01

    The capacity to withstand and repair DNA damage differs among species and plays a role in determining an organism's resistance to genotoxicity, life history, and susceptibility to disease. Environmental stressors that affect organisms at the genetic level are of particular concern in ecotoxicology due to the potential for chronic effects and trans-generational impacts on populations. Echinoderms are valuable organisms to study the relationship between DNA repair and resistance to genotoxic st...

  12. Advances and Perspectives on Tissue Repair and Healing

    Science.gov (United States)

    Pinheiro, Antonio L. B.; Marques, Aparecida M. C.; de Sousa, Ana Paula C.; Aciole, Jouber M. S.; Soares, Luiz G. P.

    2011-08-01

    Wound healing involves local and systemic responses that reflect the etiology of the lesion, type of tissue, systemic condition and others. Despite being essentially the same for different wounds, the pattern of healing may change due to intrinsic and/or extrinsic factors. The type of tissue has also to be considered. Several therapeutic approaches have been used to improve healing including phototherapies such as Laser, LEDs and Lamps. Their effects on soft and mineralized tissues are well reported. The choice of appropriated parameters is essential for the results of the treatment and includes wavelength, power density, energy, duration and frequency of application and others. We studied the effects of different types of light on the healing of both soft and mineralized tissues using different models. We found that the use of Laser and polarized light are effective on improving the healing of diabetic and undernourished animals. We also found that Laser light is capable of improving the healing of drug-induced impairment and on increasing the survival rate of flaps on both diabetic and non-diabetic animals. We have also studied and shown the influence of the laser parameters on the healing of surgical and laser wounds. Lately we verified the positive effect of LEDs on healing. We used Laser/LED light for improving bone healing in conditions such as in dental implants, autologous grafts, biomaterials and fractures. From these reports and our own experience we have no doubt whatsoever that the use of phototherapies, carried out with appropriate parameters, promotes quicker tissue repair.

  13. Evaluation of skeletal tissue repair, part 2: enhancement of skeletal tissue repair through dual-growth-factor-releasing hydrogels within an ex vivo chick femur defect model.

    Science.gov (United States)

    Smith, E L; Kanczler, J M; Gothard, D; Roberts, C A; Wells, J A; White, L J; Qutachi, O; Sawkins, M J; Peto, H; Rashidi, H; Rojo, L; Stevens, M M; El Haj, A J; Rose, F R A J; Shakesheff, K M; Oreffo, R O C

    2014-10-01

    There is an unmet need for improved, effective tissue engineering strategies to replace or repair bone damaged through disease or injury. Recent research has focused on developing biomaterial scaffolds capable of spatially and temporally releasing combinations of bioactive growth factors, rather than individual molecules, to recapitulate repair pathways present in vivo. We have developed an ex vivo embryonic chick femur critical size defect model and applied the model in the study of novel extracellular matrix (ECM) hydrogel scaffolds containing spatio-temporal combinatorial growth factor-releasing microparticles and skeletal stem cells for bone regeneration. Alginate/bovine bone ECM (bECM) hydrogels combined with poly(d,l-lactic-co-glycolic acid) (PDLLGA)/triblock copolymer (10-30% PDLLGA-PEG-PLDLGA) microparticles releasing dual combinations of vascular endothelial growth factor (VEGF), chondrogenic transforming growth factor beta 3 (TGF-β3) and the bone morphogenetic protein BMP2, with human adult Stro-1+bone marrow stromal cells (HBMSCs), were placed into 2mm central segmental defects in embryonic day 11 chick femurs and organotypically cultured. Hydrogels loaded with VEGF combinations induced host cell migration and type I collagen deposition. Combinations of TGF-β3/BMP2, particularly with Stro-1+HBMSCs, induced significant formation of structured bone matrix, evidenced by increased Sirius red-stained matrix together with collagen expression demonstrating birefringent alignment within hydrogels. This study demonstrates the successful use of the chick femur organotypic culture system as a high-throughput test model for scaffold/cell/growth factor therapies in regenerative medicine. Temporal release of dual growth factors, combined with enriched Stro-1+HBMSCs, improved the formation of a highly structured bone matrix compared to single release modalities. These studies highlight the potential of a unique alginate/bECM hydrogel dual growth factor release

  14. Association between age and repair of oxidatively damaged DNA in human peripheral blood mononuclear cells

    DEFF Research Database (Denmark)

    Løhr, Mille; Jensen, Annie; Eriksen, Louise

    2015-01-01

    It has been hypothesised that positive associations between age and levels of oxidative stress-generated damage to DNA may be related to an age-dependent decline in DNA repair activity. The objective of this study was to investigate the association between age and repair activity of oxidatively...... assay. There was an inverse association between age and DNA repair activity with a 0.65% decline in activity per year from age 18 to 83 (95% confidence interval: 0.16-1.14% per year). Univariate regression analysis also indicated inverse associations between DNA repair activity and waist-hip ratio (P...... indicating that the decline in repair activity was not mediated by metabolic risk factors. In summary...

  15. The 2015 Nobel Prize in Chemistry The Discovery of Essential Mechanisms that Repair DNA Damage.

    Science.gov (United States)

    Lindahl, Tomas; Modrich, Paul; Sancar, Aziz

    2016-01-01

    The Royal Swedish Academy awarded the Nobel Prize in Chemistry for 2015 to Tomas Lindahl, Paul Modrich and Aziz Sancar for their discoveries in fundamental mechanisms of DNA repair. This pioneering research described three different essential pathways that correct DNA damage, safeguard the integrity of the genetic code to ensure its accurate replication through generations, and allow proper cell division. Working independently of each other, Tomas Lindahl, Paul Modrich and Aziz Sancar delineated the mechanisms of base excision repair, mismatch repair and nucleotide excision repair, respectively. These breakthroughs challenged and dismissed the early view that the DNA molecule was very stable, paving the way for the discovery of human hereditary diseases associated with distinct DNA repair deficiencies and a susceptibility to cancer. It also brought a deeper understanding of cancer as well as neurodegenerative or neurological diseases, and let to novel strategies to treat cancer.

  16. Therapeutic potential of HDL in cardioprotection and tissue repair.

    Science.gov (United States)

    Van Linthout, Sophie; Frias, Miguel; Singh, Neha; De Geest, Bart

    2015-01-01

    Epidemiological studies support a strong association between high-density lipoprotein (HDL) cholesterol levels and heart failure incidence. Experimental evidence from different angles supports the view that low HDL is unlikely an innocent bystander in the development of heart failure. HDL exerts direct cardioprotective effects, which are mediated via its interactions with the myocardium and more specifically with cardiomyocytes. HDL may improve cardiac function in several ways. Firstly, HDL may protect the heart against ischaemia/reperfusion injury resulting in a reduction of infarct size and thus in myocardial salvage. Secondly, HDL can improve cardiac function in the absence of ischaemic heart disease as illustrated by beneficial effects conferred by these lipoproteins in diabetic cardiomyopathy. Thirdly, HDL may improve cardiac function by reducing infarct expansion and by attenuating ventricular remodelling post-myocardial infarction. These different mechanisms are substantiated by in vitro, ex vivo, and in vivo intervention studies that applied treatment with native HDL, treatment with reconstituted HDL, or human apo A-I gene transfer. The effect of human apo A-I gene transfer on infarct expansion and ventricular remodelling post-myocardial infarction illustrates the beneficial effects of HDL on tissue repair. The role of HDL in tissue repair is further underpinned by the potent effects of these lipoproteins on endothelial progenitor cell number, function, and incorporation, which may in particular be relevant under conditions of high endothelial cell turnover. Furthermore, topical HDL therapy enhances cutaneous wound healing in different models. In conclusion, the development of HDL-targeted interventions in these strategically chosen therapeutic areas is supported by a strong clinical rationale and significant preclinical data.

  17. New challenge of tissue repair and regenerative medicine: to achieve a perfect repair and regeneration of multiple tissues in wound sites%组织修复与再生的新挑战:实现多种组织在损伤部位的同步修复与再生

    Institute of Scientific and Technical Information of China (English)

    付小兵

    2016-01-01

    Great achievements in the study of tissue repair and regeneration have been made, and many of these successes have been shown to be beneficial to the patients in recent years.However, perfect tissue repair and regeneration of damaged tissues and organs remain to be great challenges in the management of trauma and diseases.Based on the progress in developmental biology in animals and advances in stem cell biology, it is possible to attain the aim of perfect repair and regeneration by means of somatic cell reprogramming and different inducing techniques.

  18. Coordination of altered DNA repair and damage pathways in arsenite-exposed keratinocytes.

    Science.gov (United States)

    Hamadeh, Hisham K; Trouba, Kevin J; Amin, Rupesh P; Afshari, Cynthia A; Germolec, Dori

    2002-10-01

    Human exposure to arsenic, a ubiquitous and toxic environmental pollutant, is associated with an increased incidence of skin cancer. However, the mechanism(s) associated with AsIII-mediated toxicity and carcinogenesis at low levels of exposure remains elusive. Aberrations in cell proliferation, oxidative damage, and DNA-repair fidelity have been implicated in sodium arsenite (AsIII)-mediated carcinogenicity and toxicity, but these events have been examined in isolation in the majority of biological models of arsenic exposure. We hypothesized that the simultaneous interaction of these effects may be important in arsenic-mediated neoplasia in the skin. To evaluate this, normal human epidermal keratinocytes (NHEK) were exposed to nontoxic doses (0.005-5 micro M) of AsIII and monitored for several physiological endpoints at the times when cells were harvested for gene expression measurements (1-24 h). Two-fluor cDNA microarray analyses indicated that AsIII treatment decreased the expression of genes associated with DNA repair (e.g., p53 and Damage-specific DNA-binding protein 2) and increased the expression of genes indicative of the cellular response to oxidative stress (e.g., Superoxide dismutase 1, NAD(P)H quinone oxidoreductase, and Serine/threonine kinase 25). AsIII also modulated the expression of certain transcripts associated with increased cell proliferation (e.g., Cyclin G1, Protein kinase C delta), oncogenes, and genes associated with cellular transformation (e.g., Gro-1 and V-yes). These observations correlated with measurements of cell proliferation and mitotic measurements as AsIII treatment resulted in a dose-dependent increase in cellular mitoses at 24 h and an increase in cell proliferation at 48 h of exposure. Data in this manuscript demonstrates that AsIII exposure simultaneously modulates DNA repair, cell proliferation, and redox-related gene expression in nontransformed, normal NHEK. It is anticipated that data in this report will serve as a

  19. Optical modulation study of repaired damage morphologies of fused silica by scalar diffraction theory

    Science.gov (United States)

    Li, Bo; Zhou, Qingyan; Jiang, Yong; Xiang, Xia; Liao, Wei; Jiang, Xiaolong; Wang, Haijun; Luan, Xiaoyu; Zheng, Wanguo; Yuan, Xiaodong

    2017-01-01

    The cone and Gaussian repaired damage craters are two typical morphologies induced by CO2 laser evaporation and nonevaporation technologies. The mathematical models are built for these two types of repaired craters, and the light modulation at 355 nm induced by the millimeter-scale repaired damage morphology is studied by scalar diffraction theory. The results show that the modulation of the Gaussian repaired morphology has one peak and then decreases with the increasing distance from 0 to 30 cm. While the modulation for cone repaired morphology remains stable after decreasing quickly with the increasing distance. When the horizontal radius increases, the modulation looks like a saw-tooth. However, the modulation has irregular variations for two kinds of morphologies with the increasing vertical depth. The simulated results agree well with experimental results. The horizontal and vertical dimensions, and downstream distance have different influences on the modulation. The risk of damage to downstream optical components can be suppressed to improve the stability of the optical system if the shape and size of repaired craters are well controlled and the positions of downstream optical components are selected appropriately.

  20. Photodynamic DNA damage induced by phycocyanin and its repair in Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    M. Pádula

    1999-09-01

    Full Text Available In the present study, we analyzed DNA damage induced by phycocyanin (PHY in the presence of visible light (VL using a set of repair endonucleases purified from Escherichia coli. We demonstrated that the profile of DNA damage induced by PHY is clearly different from that induced by molecules that exert deleterious effects on DNA involving solely singlet oxygen as reactive species. Most of PHY-induced lesions are single strand breaks and, to a lesser extent, base oxidized sites, which are recognized by Nth, Nfo and Fpg enzymes. High pressure liquid chromatography coupled to electrochemical detection revealed that PHY photosensitization did not induce 8-oxo-7,8-dihydro-2'-deoxyguanosine (8-oxodGuo at detectable levels. DNA repair after PHY photosensitization was also investigated. Plasmid DNA damaged by PHY photosensitization was used to transform a series of Saccharomyces cerevisiae DNA repair mutants. The results revealed that plasmid survival was greatly reduced in rad14 mutants, while the ogg1 mutation did not modify the plasmid survival when compared to that in the wild type. Furthermore, plasmid survival in the ogg1 rad14 double mutant was not different from that in the rad14 single mutant. The results reported here indicate that lethal lesions induced by PHY plus VL are repaired differently by prokaryotic and eukaryotic cells. Morever, nucleotide excision repair seems to play a major role in the recognition and repair of these lesions in Saccharomyces cerevisiae.

  1. Chromatin Dynamics in Genome Stability: Roles in Suppressing Endogenous DNA Damage and Facilitating DNA Repair

    Directory of Open Access Journals (Sweden)

    Nidhi Nair

    2017-07-01

    Full Text Available Genomic DNA is compacted into chromatin through packaging with histone and non-histone proteins. Importantly, DNA accessibility is dynamically regulated to ensure genome stability. This is exemplified in the response to DNA damage where chromatin relaxation near genomic lesions serves to promote access of relevant enzymes to specific DNA regions for signaling and repair. Furthermore, recent data highlight genome maintenance roles of chromatin through the regulation of endogenous DNA-templated processes including transcription and replication. Here, we review research that shows the importance of chromatin structure regulation in maintaining genome integrity by multiple mechanisms including facilitating DNA repair and directly suppressing endogenous DNA damage.

  2. In vitro sublethal damage repair in tumour subpopulations from a heterogeneous human colon tumour

    Energy Technology Data Exchange (ETDEWEB)

    Leith, J.T.; Vayer, A.V. Jr.; DeWyngaert, J.K.; Amols, H.; Peck, R.A. Jr.; Glicksman, A.S. (Rhode Island Hospital (USA); Brown Univ., Providence, RI (USA))

    1984-01-01

    The repair of sublethal radiation damage in two asynchronously growing tumour cell subpopulations (clones A and D) obtained from a single human adenocarcinoma biopsy specimen has been studied. The survival data found after generation of complete survival curves from split dose experiments in which exposures were separated by 3, 6, 12, or 24 h were examined. It was found that the method of performing irradiations (e.g., suspension cultures versus monolayer cultures) affected the shape of the single dose response curves, and as a result the interpretation of the amount of sublethal damage repair occurring after split dose irradiation.

  3. Aberrant repair of etheno-DNA adducts in leukocytes and colon tissue of colon cancer patients.

    Science.gov (United States)

    Obtułowicz, Tomasz; Winczura, Alicja; Speina, Elzbieta; Swoboda, Maja; Janik, Justyna; Janowska, Beata; Cieśla, Jarosław M; Kowalczyk, Paweł; Jawien, Arkadiusz; Gackowski, Daniel; Banaszkiewicz, Zbigniew; Krasnodebski, Ireneusz; Chaber, Andrzej; Olinski, Ryszard; Nair, Jagadesaan; Bartsch, Helmut; Douki, Thierry; Cadet, Jean; Tudek, Barbara

    2010-09-15

    To assess the role of lipid peroxidation-induced DNA damage and repair in colon carcinogenesis, the excision rates and levels of 1,N(6)-etheno-2'-deoxyadenosine (epsilondA), 3,N(4)-etheno-2'-deoxycytidine (epsilondC), and 1,N(2)-etheno-2'-deoxyguanosine (1,N(2)-epsilondG) were analyzed in polymorphic blood leukocytes (PBL) and resected colon tissues of 54 colorectal carcinoma (CRC) patients and PBL of 56 healthy individuals. In PBL the excision rates of 1,N(6)-ethenoadenine (epsilonAde) and 3,N(4)-ethenocytosine (epsilonCyt), measured by the nicking of oligodeoxynucleotide duplexes with single lesions, and unexpectedly also the levels of epsilondA and 1,N(2)-epsilondG, measured by LC/MS/MS, were lower in CRC patients than in controls. In contrast the mRNA levels of repair enzymes, alkylpurine- and thymine-DNA glycosylases and abasic site endonuclease (APE1), were higher in PBL of CRC patients than in those of controls, as measured by QPCR. In the target colon tissues epsilonAde and epsilonCyt excision rates were higher, whereas the epsilondA and epsilondC levels in DNA, measured by (32)P-postlabeling, were lower in tumor than in adjacent colon tissue, although a higher mRNA level was observed only for APE1. This suggests that during the onset of carcinogenesis, etheno adduct repair in the colon seems to be under a complex transcriptional and posttranscriptional control, whereby deregulation may act as a driving force for malignancy.

  4. Injection technologies for the repair of damaged concrete structures

    CERN Document Server

    Panasyuk, V V; Sylovanyuk, V P

    2014-01-01

    This book analyzes the most important achievements in science and engineering practice concerning operational factors that cause damage to concrete and reinforced concrete structures. It includes methods for assessing their strength and service life, especially those that are based on modern concepts of the fracture mechanics of materials. It also includes basic approaches to the prediction of the remaining service life for long-term operational structures. Much attention is paid to injection technologies for restoring the serviceability of damaged concrete and reinforced concrete structures. In particular, technologies for remedying holes, cracks, corrosion damages etc. The books contains sample cases in which the above technologies have been used to restore structural integrity and extend the reliable service life of concrete and reinforced concrete constructions, especially NPPs, underground railways, bridges, seaports and historical relics.

  5. Bioactive Nanocomposites for Tissue Repair and Regeneration: A Review

    Directory of Open Access Journals (Sweden)

    Jane Bramhill

    2017-01-01

    Full Text Available This review presents scientific findings concerning the use of bioactive nanocomposites in the field of tissue repair and regeneration. Bioactivity is the ability of a material to incite a specific biological reaction, usually at the boundary of the material. Nanocomposites have been shown to be ideal bioactive materials due the many biological interfaces and structures operating at the nanoscale. This has resulted in many researchers investigating nanocomposites for use in bioapplications. Nanocomposites encompass a number of different structures, incorporating organic-inorganic, inorganic-inorganic and bioinorganic nanomaterials and based upon ceramic, metallic or polymeric materials. This enables a wide range of properties to be incorporated into nanocomposite materials, such as magnetic properties, MR imaging contrast or drug delivery, and even a combination of these properties. Much of the classical research was focused on bone regeneration, however, recent advances have enabled further use in soft tissue body sites too. Despite recent technological advances, more research is needed to further understand the long-term biocompatibility impact of the use of nanoparticles within the human body.

  6. Bioactive Nanocomposites for Tissue Repair and Regeneration: A Review

    Science.gov (United States)

    Bramhill, Jane; Ross, Sukunya; Ross, Gareth

    2017-01-01

    This review presents scientific findings concerning the use of bioactive nanocomposites in the field of tissue repair and regeneration. Bioactivity is the ability of a material to incite a specific biological reaction, usually at the boundary of the material. Nanocomposites have been shown to be ideal bioactive materials due the many biological interfaces and structures operating at the nanoscale. This has resulted in many researchers investigating nanocomposites for use in bioapplications. Nanocomposites encompass a number of different structures, incorporating organic-inorganic, inorganic-inorganic and bioinorganic nanomaterials and based upon ceramic, metallic or polymeric materials. This enables a wide range of properties to be incorporated into nanocomposite materials, such as magnetic properties, MR imaging contrast or drug delivery, and even a combination of these properties. Much of the classical research was focused on bone regeneration, however, recent advances have enabled further use in soft tissue body sites too. Despite recent technological advances, more research is needed to further understand the long-term biocompatibility impact of the use of nanoparticles within the human body. PMID:28085054

  7. Cell and biomolecule delivery for tissue repair and regeneration in the central nervous system.

    Science.gov (United States)

    Elliott Donaghue, Irja; Tam, Roger; Sefton, Michael V; Shoichet, Molly S

    2014-09-28

    Tissue engineering frequently involves cells and scaffolds to replace damaged or diseased tissue. It originated, in part, as a means of effecting the delivery of biomolecules such as insulin or neurotrophic factors, given that cells are constitutive producers of such therapeutic agents. Thus cell delivery is intrinsic to tissue engineering. Controlled release of biomolecules is also an important tool for enabling cell delivery since the biomolecules can enable cell engraftment, modulate inflammatory response or otherwise benefit the behavior of the delivered cells. We describe advances in cell and biomolecule delivery for tissue regeneration, with emphasis on the central nervous system (CNS). In the first section, the focus is on encapsulated cell therapy. In the second section, the focus is on biomolecule delivery in polymeric nano/microspheres and hydrogels for the nerve regeneration and endogenous cell stimulation. In the third section, the focus is on combination strategies of neural stem/progenitor cell or mesenchymal stem cell and biomolecule delivery for tissue regeneration and repair. In each section, the challenges and potential solutions associated with delivery to the CNS are highlighted.

  8. Glycolipid biosurfactants, mannosylerythritol lipids, repair the damaged hair.

    Science.gov (United States)

    Morita, Tomotake; Kitagawa, Masaru; Yamamoto, Shuhei; Sogabe, Atsushi; Imura, Tomohiro; Fukuoka, Tokuma; Kitamoto, Dai

    2010-01-01

    Mannosylerythritol lipids (MELs), are produced from feedstock by the genus Pseudozyma, and are the most promising biosurfactants known due to its versatile interfacial and biochemical actions. In order to broaden the application in cosmetics, the hair care properties of MELs were investigated using damaged hair. On electron microscopic observation, the damaged hair was dramatically recovered with applying MEL-A and MEL-B. The tensile strength of the damaged hair increased by treatment with MEL-A (122.0 +/- 13.5 gf/p), MEL-B (119.4 +/- 7.6 gf/p) and ceramide (100.7 +/- 15.9 gf/p) compared with only lauryl glucoside (96.7 +/- 12.7 gf/p), indicating the advantage of MELs on hair care treatment. In addition, the average friction coefficient of the damaged hair was maintained after treatment with MEL-A (0.108 +/- 0.002), MEL-B (0.107 +/- 0.003) and the ceramide (0.111 +/- 0.003), although lauryl glucoside treatment increased the average friction coefficient (0.126 +/- 0.003). The increase of bending rigidity by treatment with lauryl glucoside (0.204 +/- 0.002) was prevented by treatment with MEL-A (0.129 +/- 0.002), MEL-B (0.176 +/- 0.003) and the ceramide (0.164 +/- 0.002). Consequently, MELs are proposed to be the new hair care ingredient, which are the highly useful agent for not only for the recovery of damaged hair but also for providing the smooth and flexible hair.

  9. Recombinant Technology in the Development of Materials and Systems for Soft-Tissue Repair.

    Science.gov (United States)

    Girotti, Alessandra; Orbanic, Doriana; Ibáñez-Fonseca, Arturo; Gonzalez-Obeso, Constancio; Rodríguez-Cabello, José Carlos

    2015-11-18

    The field of biomedicine is constantly investing significant research efforts in order to gain a more in-depth understanding of the mechanisms that govern the function of body compartments and to develop creative solutions for the repair and regeneration of damaged tissues. The main overall goal is to develop relatively simple systems that are able to mimic naturally occurring constructs and can therefore be used in regenerative medicine. Recombinant technology, which is widely used to obtain new tailored synthetic genes that express polymeric protein-based structures, now offers a broad range of advantages for that purpose by permitting the tuning of biological and mechanical properties depending on the intended application while simultaneously ensuring adequate biocompatibility and biodegradability of the scaffold formed by the polymers. This Progress Report is focused on recombinant protein-based materials that resemble naturally occurring proteins of interest for use in soft tissue repair. An overview of recombinant biomaterials derived from elastin, silk, collagen and resilin is given, along with a description of their characteristics and suggested applications. Current endeavors in this field are continuously providing more-improved materials in comparison with conventional ones. As such, a great effort is being made to put these materials through clinical trials in order to favor their future use.

  10. Role of Nicotinamide in DNA Damage, Mutagenesis, and DNA Repair

    Directory of Open Access Journals (Sweden)

    Devita Surjana

    2010-01-01

    Full Text Available Nicotinamide is a water-soluble amide form of niacin (nicotinic acid or vitamin B3. Both niacin and nicotinamide are widely available in plant and animal foods, and niacin can also be endogenously synthesized in the liver from dietary tryptophan. Nicotinamide is also commercially available in vitamin supplements and in a range of cosmetic, hair, and skin preparations. Nicotinamide is the primary precursor of nicotinamide adenine dinucleotide (NAD+, an essential coenzyme in ATP production and the sole substrate of the nuclear enzyme poly-ADP-ribose polymerase-1 (PARP-1. Numerous in vitro and in vivo studies have clearly shown that PARP-1 and NAD+ status influence cellular responses to genotoxicity which can lead to mutagenesis and cancer formation. This paper will examine the role of nicotinamide in the protection from carcinogenesis, DNA repair, and maintenance of genomic stability.

  11. [Scanning electron microscopy of heat-damaged bone tissue].

    Science.gov (United States)

    Harsanyl, L

    1977-02-01

    Parts of diaphyses of bones were exposed to high temperature of 200-1300 degrees C. Damage to the bone tissue caused by the heat was investigated. The scanning electron microscopic picture seems to be characteristic of the temperature applied. When the bones heated to the high temperature of 700 degrees C characteristic changes appear on the periostal surface, higher temperatura on the other hand causes damage to the compact bone tissue and can be observed on the fracture-surface. Author stresses the importance of this technique in the legal medicine and anthropology.

  12. Protecting DNA from errors and damage: an overview of DNA repair mechanisms in plants compared to mammals.

    Science.gov (United States)

    Spampinato, Claudia P

    2017-05-01

    The genome integrity of all organisms is constantly threatened by replication errors and DNA damage arising from endogenous and exogenous sources. Such base pair anomalies must be accurately repaired to prevent mutagenesis and/or lethality. Thus, it is not surprising that cells have evolved multiple and partially overlapping DNA repair pathways to correct specific types of DNA errors and lesions. Great progress in unraveling these repair mechanisms at the molecular level has been made by several talented researchers, among them Tomas Lindahl, Aziz Sancar, and Paul Modrich, all three Nobel laureates in Chemistry for 2015. Much of this knowledge comes from studies performed in bacteria, yeast, and mammals and has impacted research in plant systems. Two plant features should be mentioned. Plants differ from higher eukaryotes in that they lack a reserve germline and cannot avoid environmental stresses. Therefore, plants have evolved different strategies to sustain genome fidelity through generations and continuous exposure to genotoxic stresses. These strategies include the presence of unique or multiple paralogous genes with partially overlapping DNA repair activities. Yet, in spite (or because) of these differences, plants, especially Arabidopsis thaliana, can be used as a model organism for functional studies. Some advantages of this model system are worth mentioning: short life cycle, availability of both homozygous and heterozygous lines for many genes, plant transformation techniques, tissue culture methods and reporter systems for gene expression and function studies. Here, I provide a current understanding of DNA repair genes in plants, with a special focus on A. thaliana. It is expected that this review will be a valuable resource for future functional studies in the DNA repair field, both in plants and animals.

  13. Self-repairing control for damaged robotic manipulators

    Energy Technology Data Exchange (ETDEWEB)

    Eisler, G.R.; Robinett, R.D.; Dohrmann, C.R.; Driessen, B.J. [and others

    1997-03-01

    Algorithms have been developed allowing operation of robotic systems under damaged conditions. Specific areas addressed were optimal sensor location, adaptive nonlinear control, fault-tolerant robot design, and dynamic path-planning. A seven-degree-of-freedom, hydraulic manipulator, with fault-tolerant joint design was also constructed and tested. This report completes this project which was funded under the Laboratory Directed Research and Development program.

  14. Damage mechanisms for ultrasound-induced cavitation in tissue

    Science.gov (United States)

    Warnez, M.; Vlaisavljevich, E.; Xu, Z.; Johnsen, E.

    2017-03-01

    In a variety of biomedical applications, cavitation occurs in soft tissue. Although significant amounts of research have been performed on cavitation in water, bubble dynamics, and related bioeffects remain poorly understood. We use numerical simulations of spherical bubble dynamics in soft tissue to assess the extent to which viscoelasticity affects "known" and introduces "new" damage mechanisms. We find that deviatoric stresses - although not an important damage mechanism in water - are significantly enhanced and could be an important bioeffect mechanism in tissue. Both the viscoelastic properties and the nonlinear, large-collapse radius contribute to stress amplification in the surroundings. In addition, temperatures in the surrounding medium increase more in the Zener tissue than in water, due to viscous heating.

  15. DNA damage response and repair data with pharmacological modulators of Tousled

    Directory of Open Access Journals (Sweden)

    Prakash Srinivasan Timiri Shanmugam

    2016-06-01

    Full Text Available Human Tousled kinase 1 (TLK1 plays an important role in chromatin remodeling, replication, and DNA damage response and repair. TLK1 activity is immediately, but transiently, downregulated after genotoxic insult, and its recovery is important for exit from checkpoint arrest and cell survival after radiation. The data in this article compliments research presented in the paper titled, “Tousled kinase activator, gallic acid, promotes DNA repair and suppresses radiation cytotoxicity in salivary gland cells” [1]. The identification of small molecule activators and inhibitors of TLK1 provided an opportunity to pharmacologically alter the protein׳s activity to elucidate its role in DNA damage response pathways. TLK1 effectors, gallic acid (GA and thioridazine (THD activate and inhibit the kinase, respectively, and the data report on the impact of these compounds and the significance of TLK1 to DNA break repair and the survival of human salivary acinar cells.

  16. New discoveries linking transcription to DNA repair and damage tolerance pathways.

    Science.gov (United States)

    Cohen, Susan E; Walker, Graham C

    2011-01-01

    In Escherichia coli, the transcription elongation factor NusA is associated with all elongating RNA polymerases where it functions in transcription termination and antitermination. Here, we review our recent results implicating NusA in the recruitment of DNA repair and damage tolerance mechanisms to sites of stalled transcription complexes.

  17. The Fanconi anemia DNA damage repair pathway in the spotlight for germline predisposition to colorectal cancer

    Science.gov (United States)

    Esteban-Jurado, Clara; Franch-Expósito, Sebastià; Muñoz, Jenifer; Ocaña, Teresa; Carballal, Sabela; López-Cerón, Maria; Cuatrecasas, Miriam; Vila-Casadesús, Maria; Lozano, Juan José; Serra, Enric; Beltran, Sergi; Brea-Fernández, Alejandro; Ruiz-Ponte, Clara; Castells, Antoni; Bujanda, Luis; Garre, Pilar; Caldés, Trinidad; Cubiella, Joaquín; Balaguer, Francesc; Castellví-Bel, Sergi

    2016-01-01

    Colorectal cancer (CRC) is one of the most common neoplasms in the world. Fanconi anemia (FA) is a very rare genetic disease causing bone marrow failure, congenital growth abnormalities and cancer predisposition. The comprehensive FA DNA damage repair pathway requires the collaboration of 53 proteins and it is necessary to restore genome integrity by efficiently repairing damaged DNA. A link between FA genes in breast and ovarian cancer germline predisposition has been previously suggested. We selected 74 CRC patients from 40 unrelated Spanish families with strong CRC aggregation compatible with an autosomal dominant pattern of inheritance and without mutations in known hereditary CRC genes and performed germline DNA whole-exome sequencing with the aim of finding new candidate germline predisposition variants. After sequencing and data analysis, variant prioritization selected only those very rare alterations, producing a putative loss of function and located in genes with a role compatible with cancer. We detected an enrichment for variants in FA DNA damage repair pathway genes in our familial CRC cohort as 6 families carried heterozygous, rare, potentially pathogenic variants located in BRCA2/FANCD1, BRIP1/FANCJ, FANCC, FANCE and REV3L/POLZ. In conclusion, the FA DNA damage repair pathway may play an important role in the inherited predisposition to CRC. PMID:27165003

  18. Differential contributions of mammalian Rad54 paralogs to recombination, DNA damage repair, and meiosis.

    NARCIS (Netherlands)

    J. Wesoly (Joanna); S. Agarwal (Sheba); S. Sigurdsson (Stefan); W. Bussen (Wendy); S. Komen (Stephen); J. Qin (Jian); H. van Steeg (Harry); J. van Benthem (Jan); E. Wassenaar (Evelyne); W.M. Baarends (Willy); M. Ghazvini (Mehrnaz); A. Tafel (Agnieszka); H. Heath (Helen); N.J. Galjart (Niels); J. Essers (Jeroen); J.A. Grootegoed (Anton); N. Arnheim (Norman); O.Y. Bezzubova (Olga); J-M. Buerstedde; P. Sung (Patrick); R. Kanaar (Roland)

    2006-01-01

    textabstractHomologous recombination is a versatile DNA damage repair pathway requiring Rad51 and Rad54. Here we show that a mammalian Rad54 paralog, Rad54B, displays physical and functional interactions with Rad51 and DNA that are similar to those of Rad54. While ablation of Rad54 in mouse embryoni

  19. A bivariate optimal replacement policy with cumulative repair cost limit under cumulative damage model

    Indian Academy of Sciences (India)

    MIN-T SAI LAI; SHIH-CHIH CHEN

    2016-05-01

    In this paper, a bivariate replacement policy (n, T) for a cumulative shock damage process is presented that included the concept of cumulative repair cost limit. The arrival shocks can be divided into two kinds of shocks. Each type-I shock causes a random amount of damage and these damages are additive. When the total damage exceeds a failure level, the system goes into serious failure. Type-II shock causes the system into minor failure and such a failure can be corrected by minimal repair. When a minor failure occurs, the repaircost will be evaluated and minimal repair is executed if the accumulated repair cost is less than a predetermined limit L. The system is replaced at scheduled time T, at n-th minor failure, or at serious failure. The long-term expected cost per unit time is derived using the expected costs as the optimality criterion. The minimum-cost policy is derived, and existence and uniqueness of the optimal n* and T* are proved. This bivariate optimal replacement policy (n, T) is showed to be better than the optimal T* and the optimal n* policy.

  20. Human embryonic stem cells have enhanced repair of multiple forms of DNA damage

    DEFF Research Database (Denmark)

    Maynard, Scott; Swistowska, Anna Maria; Lee, Jae Wan

    2008-01-01

    fibroblasts (WI-38, hs27) and, with the exception of UV-C damage, HeLa cells. Microarray gene expression analysis showed that mRNA levels of several DNA repair genes are elevated in human embryonic stem cells compared with their differentiated forms (embryoid bodies). These data suggest that genomic...

  1. Human papillomavirus mediated inhibition of DNA damage sensing and repair drives skin carcinogenesis

    NARCIS (Netherlands)

    M. Hufbauer (Martin); J. Cooke (James); G.T.J. van der Horst (Gijsbertus); H. Pfister (Herbert); A. Storey (Alan); B. Akgül (Baki)

    2015-01-01

    textabstractBackground: The failure to mount an effective DNA damage response to repair UV induced cyclobutane pyrimidine dimers (CPDs) results in an increased propensity to develop cutaneous squamous cell carcinoma (cSCC). High-risk patient groups, such as organ transplant recipients (OTRs)

  2. Probing multi-scale mechanical damage in connective tissues using X-ray diffraction.

    Science.gov (United States)

    Bianchi, Fabio; Hofmann, Felix; Smith, Andrew J; Thompson, Mark S

    2016-11-01

    The accumulation of microstructural collagen damage following repetitive loading is linked to painful and debilitating tendon injuries. As a hierarchical, semi-crystalline material, collagen mechanics can be studied using X-ray diffraction. The aim of the study was to describe multi-structural changes in tendon collagen following controlled plastic damage (5% permanent strain). We used small angle X-ray scattering (SAXS) to interrogate the spacing of collagen molecules within a fibril, and wide angle X-ray scattering (WAXS) to measure molecular strains under macroscopic loading. Simultaneous recordings of SAXS and WAXS patterns, together with whole-tissue strain in physiologically hydrated rat-tail tendons were made during increments of in situ tensile loading. Results showed that while tissue level modulus was unchanged, fibril modulus decreased significantly, and molecular modulus significantly increased. Further, analysis of higher order SAXS peaks suggested structural changes in the gap and overlap regions, possibly localising the damage to molecular cross-links. Our results provide new insight into the fundamental damage processes at work in collagenous tissues and point to new directions for their mitigation and repair.

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

    Science.gov (United States)

    Sterpone, Silvia; Cozzi, Renata

    2010-01-01

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

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

    Directory of Open Access Journals (Sweden)

    Silvia Sterpone

    2010-01-01

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

  5. Are glutathione S transferases involved in DNA damage signalling? Interactions with DNA damage and repair revealed from molecular epidemiology studies

    Energy Technology Data Exchange (ETDEWEB)

    Dusinska, Maria, E-mail: Maria.DUSINSKA@nilu.no [CEE-Health Effects Group, NILU - Norwegian Institute for Air Research, Kjeller (Norway); Staruchova, Marta; Horska, Alexandra [Department of Experimental and Applied Genetics, Slovak Medical University, Bratislava (Slovakia); Smolkova, Bozena [Laboratory of Cancer Genetics, Cancer Research Institute of the Slovak Academy of Sciences, Bratislava (Slovakia); Collins, Andrew [Department of Nutrition, Faculty of Medicine, University of Oslo (Norway); Bonassi, Stefano [Unit of Clinical and Molecular Epidemiology, IRCCS San Raffaele Pisana, Rome (Italy); Volkovova, Katarina [Department of Experimental and Applied Genetics, Slovak Medical University, Bratislava (Slovakia)

    2012-08-01

    Glutathione S-transferases (GSTs) are members of a multigene family of isoenzymes that are important in the control of oxidative stress and in phase II metabolism. Acting non-enzymically, GSTs can modulate signalling pathways of cell proliferation, cell differentiation and apoptosis. Using a molecular epidemiology approach, we have investigated a potential involvement of GSTs in DNA damage processing, specifically the modulation of DNA repair in a group of 388 healthy adult volunteers; 239 with at least 5 years of occupational exposure to asbestos, stone wool or glass fibre, and 149 reference subjects. We measured DNA damage in lymphocytes using the comet assay (alkaline single cell gel electrophoresis): strand breaks (SBs) and alkali-labile sites, oxidised pyrimidines with endonuclease III, and oxidised purines with formamidopyrimidine DNA glycosylase. We also measured GST activity in erythrocytes, and the capacity for base excision repair (BER) in a lymphocyte extract. Polymorphisms in genes encoding three GST isoenzymes were determined, namely deletion of GSTM1 and GSTT1 and single nucleotide polymorphism Ile105Val in GSTP1. Consumption of vegetables and wine correlated negatively with DNA damage and modulated BER. GST activity correlated with oxidised bases and with BER capacity, and differed depending on polymorphisms in GSTP1, GSTT1 and GSTM1. A significantly lower BER rate was associated with the homozygous GSTT1 deletion in all asbestos site subjects and in the corresponding reference group. Multifactorial analysis revealed effects of sex and exposure in GSTP1 Ile/Val heterozygotes but not in Ile/Ile homozygotes. These variants affected also SBs levels, mainly by interactions of GSTP1 genotype with exposure, with sex, and with smoking habit; and by an interaction between sex and smoking. Our results show that GST polymorphisms and GST activity can apparently influence DNA stability and repair of oxidised bases, suggesting a potential new role for these

  6. Location of DNA damage by charge exchanging repair enzymes: effects of cooperativity on location time

    Directory of Open Access Journals (Sweden)

    Eriksen Kasper

    2005-04-01

    Full Text Available Abstract Background How DNA repair enzymes find the relatively rare sites of damage is not known in great detail. Recent experiments and molecular data suggest that individual repair enzymes do not work independently of each other, but interact with each other through charges exchanged along the DNA. A damaged site in the DNA hinders this exchange. The hypothesis is that the charge exchange quickly liberates the repair enzymes from error-free stretches of DNA. In this way, the sites of damage are located more quickly; but how much more quickly is not known, nor is it known whether the charge exchange mechanism has other observable consequences. Results Here the size of the speed-up gained from this charge exchange mechanism is calculated and the characteristic length and time scales are identified. In particular, for Escherichia coli, I estimate the speed-up is 50000/N, where N is the number of repair enzymes participating in the charge exchange mechanism. Even though N is not exactly known, a speed-up of order 10 is not entirely unreasonable. Furthermore, upon over expression of all the repair enzymes, the location time only varies as N-1/2 and not as 1/N. Conclusion The revolutionary hypothesis that DNA repair enzymes use charge exchange along DNA to locate damaged sites more efficiently is actually sound from a purely theoretical point of view. Furthermore, the predicted collective behavior of the location time is important in assessing the impact of stress-ful and radioactive environments on individual cell mutation rates.

  7. Tissue-type plasminogen activator deficiency delays bone repair: roles of osteoblastic proliferation and vascular endothelial growth factor.

    Science.gov (United States)

    Kawao, Naoyuki; Tamura, Yukinori; Okumoto, Katsumi; Yano, Masato; Okada, Kiyotaka; Matsuo, Osamu; Kaji, Hiroshi

    2014-08-01

    Further development in research of bone regeneration is necessary to meet the clinical demand for bone reconstruction. Recently, we reported that plasminogen is crucial for bone repair through enhancement of vessel formation. However, the details of the role of tissue-type plasminogen activator (tPA) and urokinase-type plasminogen activator (uPA) in the bone repair process still remain unknown. Herein, we examined the effects of plasminogen activators on bone repair after a femoral bone defect using tPA-deficient (tPA(-/-)) and uPA-deficient (uPA(-/-)) mice. Bone repair of the femur was delayed in tPA(-/-) mice, unlike that in wild-type (tPA(+/+)) mice. Conversely, the bone repair was comparable between wild-type (uPA(+/+)) and uPA(-/-) mice. The number of proliferative osteoblasts was decreased at the site of bone damage in tPA(-/-) mice. Moreover, the proliferation of primary calvarial osteoblasts was reduced in tPA(-/-) mice. Recombinant tPA facilitated the proliferation of mouse osteoblastic MC3T3-E1 cells. The proliferation enhanced by tPA was antagonized by the inhibition of endogenous annexin 2 by siRNA and by the inhibition of extracellular signal-regulated kinase (ERK)1/2 phosphorylation in MC3T3-E1 cells. Vessel formation as well as the levels of vascular endothelial growth factor (VEGF) and hypoxia-inducible factor-1α (HIF-1α) were decreased at the damaged site in tPA(-/-) mice. Our results provide novel evidence that tPA is crucial for bone repair through the facilitation of osteoblast proliferation related to annexin 2 and ERK1/2 as well as enhancement of vessel formation related to VEGF and HIF-1α at the site of bone damage. Copyright © 2014 the American Physiological Society.

  8. High elastic modulus nanoparticles: a novel tool for subfailure connective tissue matrix damage.

    Science.gov (United States)

    Empson, Yvonne M; Ekwueme, Emmanuel C; Hong, Jung K; Paynter, Danielle M; Kwansa, Albert L; Brown, Chalmers; Pekkanen, Allison M; Roman, Maren; Rylander, Nichole M; Brolinson, Gunnar P; Freeman, Joseph W

    2014-09-01

    Subfailure matrix injuries such as sprains and strains account for a considerable portion of ligament and tendon pathologies. In addition to the lack of a robust biological healing response, these types of injuries are often characterized by seriously diminished matrix biomechanics. Recent work has shown nanosized particles, such as nanocarbons and nanocellulose, to be effective in modulating cell and biological matrix responses for biomedical applications. In this article, we investigate the feasibility and effect of using high stiffness nanostructures of varying size and shape as nanofillers to mechanically reinforce damaged soft tissue matrices. To this end, nanoparticles (NPs) were characterized using atomic force microscopy and dynamic light scattering techniques. Next, we used a uniaxial tensile injury model to test connective tissue (porcine skin and tendon) biomechanical response to NP injections. After injection into damaged skin and tendon specimens, the NPs, more notably nanocarbons in skin, led to an increase in elastic moduli and yield strength. Furthermore, rat primary patella tendon fibroblast cell activity evaluated using the metabolic water soluble tetrazolium salt assay showed no cytotoxicity of the NPs studied, instead after 21 days nanocellulose-treated tenocytes exhibited significantly higher cell activity when compared with nontreated control tenocytes. Dispersion of nanocarbons injected by solution into tendon tissue was investigated through histologic studies, revealing effective dispersion and infiltration in the treated region. Such results suggest that these high modulus NPs could be used as a tool for damaged connective tissue repair.

  9. Systematic analysis of DNA damage induction and DNA repair pathway activation by continuous wave visible light laser micro-irradiation

    Directory of Open Access Journals (Sweden)

    Britta Muster

    2017-02-01

    Full Text Available Laser micro-irradiation can be used to induce DNA damage with high spatial and temporal resolution, representing a powerful tool to analyze DNA repair in vivo in the context of chromatin. However, most lasers induce a mixture of DNA damage leading to the activation of multiple DNA repair pathways and making it impossible to study individual repair processes. Hence, we aimed to establish and validate micro-irradiation conditions together with inhibition of several key proteins to discriminate different types of DNA damage and repair pathways using lasers commonly available in confocal microscopes. Using time-lapse analysis of cells expressing fluorescently tagged repair proteins and also validation of the DNA damage generated by micro-irradiation using several key damage markers, we show that irradiation with a 405 nm continuous wave laser lead to the activation of all repair pathways even in the absence of exogenous sensitization. In contrast, we found that irradiation with 488 nm laser lead to the selective activation of non-processive short-patch base excision and single strand break repair, which were further validated by PARP inhibition and metoxyamine treatment. We conclude that these low energy conditions discriminated against processive long-patch base excision repair, nucleotide excision repair as well as double strand break repair pathways.

  10. Oxidative DNA damage background estimated by a system model of base excision repair.

    Science.gov (United States)

    Sokhansanj, Bahrad A; Wilson, David M

    2004-08-01

    Human DNA can be damaged by natural metabolism through free radical production. It has been suggested that the equilibrium between innate damage and cellular DNA repair results in an oxidative DNA damage background that potentially contributes to disease and aging. Efforts to quantitatively characterize the human oxidative DNA damage background level, based on measuring 8-oxoguanine lesions as a biomarker, have led to estimates that vary over three to four orders of magnitude, depending on the method of measurement. We applied a previously developed and validated quantitative pathway model of human DNA base excision repair, integrating experimentally determined endogenous damage rates and model parameters from multiple sources. Our estimates of at most 100 8-oxoguanine lesions per cell are consistent with the low end of data from biochemical and cell biology experiments, a result robust to model limitations and parameter variation. Our findings show the power of quantitative system modeling to interpret composite experimental data and make biologically and physiologically relevant predictions for complex human DNA repair pathway mechanisms and capacity.

  11. Oxidative DNA damage background estimated by a system model of base excision repair

    Energy Technology Data Exchange (ETDEWEB)

    Sokhansanj, B A; Wilson, III, D M

    2004-05-13

    Human DNA can be damaged by natural metabolism through free radical production. It has been suggested that the equilibrium between innate damage and cellular DNA repair results in an oxidative DNA damage background that potentially contributes to disease and aging. Efforts to quantitatively characterize the human oxidative DNA damage background level based on measuring 8-oxoguanine lesions as a biomarker have led to estimates varying over 3-4 orders of magnitude, depending on the method of measurement. We applied a previously developed and validated quantitative pathway model of human DNA base excision repair, integrating experimentally determined endogenous damage rates and model parameters from multiple sources. Our estimates of at most 100 8-oxoguanine lesions per cell are consistent with the low end of data from biochemical and cell biology experiments, a result robust to model limitations and parameter variation. Our results show the power of quantitative system modeling to interpret composite experimental data and make biologically and physiologically relevant predictions for complex human DNA repair pathway mechanisms and capacity.

  12. Relationships between chromatin remodeling and DNA damage repair induced by 8-methoxypsoralen and UVA in yeast Saccharomyces cerevisiae

    Directory of Open Access Journals (Sweden)

    Lavínia Almeida Cruz

    2012-01-01

    Full Text Available Eukaryotic cells have developed mechanisms to prevent genomic instability, such as DNA damage detection and repair, control of cell cycle progression and cell death induction. The bifunctional compound furocumarin 8-methoxy-psoralen (8-MOP is widely used in the treatment of various inflammatory skin diseases. In this review, we summarize recent data about the role of chromatin remodeling in the repair of DNA damage induced by treatment with 8-methoxypsoralen plus UVA (8-MOP+UVA, focusing on repair proteins in budding yeast Saccharomyces cerevisiae, an established model system for studying DNA repair pathways. The interstrand crosslinks (ICL formed by the 8-MOP+UVA treatment are detrimental lesions that can block transcription and replication, leading to cell death if not repaired. Current data show the involvement of different pathways in ICL processing, such as nucleotide excision repair (NER, base excision repair (BER, translesion repair (TLS and double-strand break repair. 8-MOP+UVA treatment in yeast enhances the expression of genes involved in the DNA damage response, double strand break repair by homologous replication, as well as genes related to cell cycle regulation. Moreover, alterations in the expression of subtelomeric genes and genes related to chromatin remodeling are consistent with structural modifications of chromatin relevant to DNA repair. Taken together, these findings indicate a specific profile in 8-MOP+UVA responses related to chromatin remodeling and DNA repair.

  13. Experimental assessment of concrete damage due to exposure to high temperature and efficacy of the repair system

    Directory of Open Access Journals (Sweden)

    Guruprasad Y.K.

    2013-09-01

    Full Text Available The present study experimentally evaluates the performance of control (standard cylinder specimen, damaged (mechanical loading after thermal exposure and repaired / retrofitted normal plain concrete cylinders using different repair schemes such as on use of FRP wraps, Geo-polymers, etc., to restore the capacity of damaged structural concrete elements. The control-companion specimen in the series provides the reference frame against which both, specimen damage levels were quantified and the benefits of a specimen repaired subsequent to damage were assessed.

  14. DNA damage and repair in plants under ultraviolet and ionizing radiations.

    Science.gov (United States)

    Gill, Sarvajeet S; Anjum, Naser A; Gill, Ritu; Jha, Manoranjan; Tuteja, Narendra

    2015-01-01

    Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV) and ionizing radiations (IR). Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315-400 nm; UV-B, 280-315 nm; and UV-C, exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a) introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b) critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context.

  15. Repair of oxidative DNA damage, cell-cycle regulation and neuronal death may influence the clinical manifestation of Alzheimer's disease.

    Directory of Open Access Journals (Sweden)

    Aderbal R T Silva

    Full Text Available Alzheimer's disease (AD is characterized by progressive cognitive decline associated with a featured neuropathology (neuritic plaques and neurofibrillary tangles. Several studies have implicated oxidative damage to DNA, DNA repair, and altered cell-cycle regulation in addition to cell death in AD post-mitotic neurons. However, there is a lack of studies that systematically assess those biological processes in patients with AD neuropathology but with no evidence of cognitive impairment. We evaluated markers of oxidative DNA damage (8-OHdG, H2AX, DNA repair (p53, BRCA1, PTEN, and cell-cycle (Cdk1, Cdk4, Cdk5, Cyclin B1, Cyclin D1, p27Kip1, phospho-Rb and E2F1 through immunohistochemistry and cell death through TUNEL in autopsy hippocampal tissue samples arrayed in a tissue microarray (TMA composed of three groups: I "clinical-pathological AD" (CP-AD--subjects with neuropathological AD (Braak ≥ IV and CERAD = B or C and clinical dementia (CDR ≥ 2, IQCODE>3.8; II "pathological AD" (P-AD--subjects with neuropathological AD (Braak ≥ IV and CERAD = B or C and without cognitive impairment (CDR 0, IQCODE<3.2; and III "normal aging" (N--subjects without neuropathological AD (Braak ≤ II and CERAD 0 or A and with normal cognitive function (CDR 0, IQCODE<3.2. Our results show that high levels of oxidative DNA damage are present in all groups. However, significant reductions in DNA repair and cell-cycle inhibition markers and increases in cell-cycle progression and cell death markers in subjects with CP-AD were detected when compared to both P-AD and N groups, whereas there were no significant differences in the studied markers between P-AD individuals and N subjects. This study indicates that, even in the setting of pathological AD, healthy cognition may be associated with a preserved repair to DNA damage, cell-cycle regulation, and cell death in post-mitotic neurons.

  16. [Study on repair capacity of DNA damage associated with chronic benzene poisoning].

    Science.gov (United States)

    Xing, Cai-hong; Ji, Zhi-ying; Li, Gui-lan; Yin, Song-nian

    2006-07-01

    To explore the repair capacity of DNA damage associated with chronic benzene poisonings. 63 workers suffered from chronic benzene poisonings and 45 workers exposed to benzene, who were engaged in the same job title, were investigated. Comet assay and cytokinesis-block micronucleus (CBMN) detection were used to evaluate gamma-radiation-induced DNA and chromosomal damage and repair capacity in peripheral blood lymphocyte. The comet tail length difference of the benzene poisoning group (4.64 +/- 1.57 microm) was significantly higher than that of the control group (3.77 +/- 1.30 microm) (P = 0.0029). There was no significant difference of the 3AB index between the poisoning group and the control group. The relative risk of benzene poisoning in the subject with comet tail length difference > 3.81 was significantly higher than that in the subject with comet tail length difference poisoning in the subject with 3AB index or = 0.20. DNA repair capacity on DNA-strand level might tightly associate with chronic benzene poisoning. The DNA repair capacity on DNA-strand level would be worse, and the benzene poisoning risk could be higher. There was no clear relation between the DNA repair capacity on chromosome level and the benzene poisoning risk.

  17. Tissue-engineering strategies to repair joint tissue in osteoarthritis: nonviral gene-transfer approaches.

    Science.gov (United States)

    Madry, Henning; Cucchiarini, Magali

    2014-10-01

    Loss of articular cartilage is a common clinical consequence of osteoarthritis (OA). In the past decade, substantial progress in tissue engineering, nonviral gene transfer, and cell transplantation have provided the scientific foundation for generating cartilaginous constructs from genetically modified cells. Combining tissue engineering with overexpression of therapeutic genes enables immediate filling of a cartilage defect with an engineered construct that actively supports chondrogenesis. Several pioneering studies have proved that spatially defined nonviral overexpression of growth-factor genes in constructs of solid biomaterials or hydrogels is advantageous compared with gene transfer or scaffold alone, both in vitro and in vivo. Notably, these investigations were performed in models of focal cartilage defects, because advanced cartilage-repair strategies based on the principles of tissue engineering have not advanced sufficiently to enable resurfacing of extensively degraded cartilage as therapy for OA. These studies serve as prototypes for future technological developments, because they raise the possibility that cartilage constructs engineered from genetically modified chondrocytes providing autocrine and paracrine stimuli could similarly compensate for the loss of articular cartilage in OA. Because cartilage-tissue-engineering strategies are already used in the clinic, combining tissue engineering and nonviral gene transfer could prove a powerful approach to treat OA.

  18. 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.

  19. The Comet-FISH assay for the analysis of DNA damage and repair.

    Science.gov (United States)

    Spivak, Graciela

    2010-01-01

    In this chapter, I describe the alkaline single-cell gel electrophoresis (Comet assay) combined with fluorescence in situ hybridization (FISH) technology, used in our laboratory, to study the incidence and repair of lesions induced in human cells by ultraviolet light. The Comet-FISH method permits the simultaneous and comparative analysis of DNA damage and its repair throughout the genome and in defined chromosomal regions. This very sensitive approach can be applied to any lesion, such as those induced by chemical carcinogens and products of cellular metabolism that can be converted to DNA single- or double-strand breaks. The unique advantages and limitations of the method for particular applications are discussed.

  20. Carcinoma cells misuse the host tissue damage response to invade the brain

    Science.gov (United States)

    Chuang, Han-Ning; van Rossum, Denise; Sieger, Dirk; Siam, Laila; Klemm, Florian; Bleckmann, Annalen; Bayerlová, Michaela; Farhat, Katja; Scheffel, Jörg; Schulz, Matthias; Dehghani, Faramarz; Stadelmann, Christine; Hanisch, Uwe-Karsten; Binder, Claudia; Pukrop, Tobias

    2013-01-01

    The metastatic colonization of the brain by carcinoma cells is still barely understood, in particular when considering interactions with the host tissue. The colonization comes with a substantial destruction of the surrounding host tissue. This leads to activation of damage responses by resident innate immune cells to protect, repair, and organize the wound healing, but may distract from tumoricidal actions. We recently demonstrated that microglia, innate immune cells of the CNS, assist carcinoma cell invasion. Here we report that this is a fatal side effect of a physiological damage response of the brain tissue. In a brain slice coculture model, contact with both benign and malignant epithelial cells induced a response by microglia and astrocytes comparable to that seen at the interface of human cerebral metastases. While the glial damage response intended to protect the brain from intrusion of benign epithelial cells by inducing apoptosis, it proved ineffective against various malignant cell types. They did not undergo apoptosis and actually exploited the local tissue reaction to invade instead. Gene expression and functional analyses revealed that the C-X-C chemokine receptor type 4 (CXCR4) and WNT signaling were involved in this process. Furthermore, CXCR4-regulated microglia were recruited to sites of brain injury in a zebrafish model and CXCR4 was expressed in human stroke patients, suggesting a conserved role in damage responses to various types of brain injuries. Together, our findings point to a detrimental misuse of the glial damage response program by carcinoma cells resistant to glia-induced apoptosis. PMID:23832647

  1. Neuromuscular Damage and Repair after Dry Needling in Mice

    Directory of Open Access Journals (Sweden)

    Ares Domingo

    2013-01-01

    Full Text Available Objective. Some dry needling treatments involve repetitive and rapid needle insertions into myofascial trigger points. This type of treatment causes muscle injury and can also damage nerve fibers. The aim of this study is to determine the injury caused by 15 repetitive punctures in the muscle and the intramuscular nerves in healthy mouse muscle and its ulterior regeneration. Methods. We repeatedly needled the levator auris longus muscle of mice, and then the muscles were processed with immunohistochemistry, methylene blue, and electron microscopy techniques. Results. Three hours after the dry needling procedure, the muscle fibers showed some signs of an inflammatory response, which progressed to greater intensity 24 hours after the procedure. Some inflammatory cells could still be seen when the muscle regeneration was almost complete seven days after the treatment. One day after the treatment, some changes in the distribution of receptors could be observed in the denervated postsynaptic component. Reinnervation was complete by the third day after the dry needling procedure. We also saw very fine axonal branches reinnervating all the postsynaptic components and some residual sprouts the same day. Conclusion. Repeated dry needling punctures in muscle do not perturb the different stages of muscle regeneration and reinnervation.

  2. Zebrafish fin regeneration after cryoinjury-induced tissue damage

    Directory of Open Access Journals (Sweden)

    Bérénice Chassot

    2016-06-01

    Full Text Available Although fin regeneration following an amputation procedure has been well characterized, little is known about the impact of prolonged tissue damage on the execution of the regenerative programme in the zebrafish appendages. To induce histolytic processes in the caudal fin, we developed a new cryolesion model that combines the detrimental effects of freezing/thawing and ischemia. In contrast to the common transection model, the damaged part of the fin was spontaneously shed within two days after cryoinjury. The remaining stump contained a distorted margin with a mixture of dead material and healthy cells that concomitantly induced two opposing processes of tissue debris degradation and cellular proliferation, respectively. Between two and seven days after cryoinjury, this reparative/proliferative phase was morphologically featured by displaced fragments of broken bones. A blastemal marker msxB was induced in the intact mesenchyme below the damaged stump margin. Live imaging of epithelial and osteoblastic transgenic reporter lines revealed that the tissue-specific regenerative programmes were initiated after the clearance of damaged material. Despite histolytic perturbation during the first week after cryoinjury, the fin regeneration resumed and was completed without further alteration in comparison to the simple amputation model. This model reveals the powerful ability of the zebrafish to restore the original appendage architecture after the extended histolysis of the stump.

  3. From repairing the damaged landscape to restoration project

    Directory of Open Access Journals (Sweden)

    Céline Granjou

    2010-10-01

    Full Text Available The study adopts an empirical sociological approach to analyse how the objectives behind the revegetation of ski trails and runs in the French alpine resort of Alpe d’Huez have evolved since the 1970s. A revegetation programme was first introduced to repair the scars left by the works conducted to equip the resort with infrastructures, and then, over time, it became a more complex restoration project. At first, revegetation techniques were developed to fight soil erosion, but soon also became associated with the idea of “turning the mountain green again”. Now, 40 years later, revegetation is aimed at restoring both a natural ecosystem and a cultural landscape. The ski resort’s managers, local farmers, technicians, and those conducting research in the area share a common desire to promote autochthony, which in some cases runs the risk of reproducing folklore. Far from adopting an overriding ethical perspective, the study suggests that the area’s physical characteristics, specific history and configuration of local actors have shaped and continue to shape both the manner in which ecological restoration is implemented, through political choices and technical decisions, and the debates it gives rise to. The study concludes by examining the specificity of the findings for Alpe d’Huez and discussing their validity for other alpine ski resorts.A partir d’une approche sociologique empirique, ce texte propose une analyse de la mise en œuvre de la revégétalisation sur la station de l’Alpe d’Huez depuis les années 1970. Il montre comment la revégétalisation est passée d’un objectif de réparation des cicatrices provoquées par les aménagements à une entreprise plus complexe de restauration. S’il s’agissait au départ de répondre à un objectif technique de lutte contre l’érosion, la revégétalisation a pris rapidement une tournure paysagère (reverdissement ; elle a ensuite été pensée dans une perspective de

  4. Dietary Berries and Ellagic Acid Prevent Oxidative DNA Damage and Modulate Expression of DNA Repair Genes

    Directory of Open Access Journals (Sweden)

    Ramesh C. Gupta

    2008-03-01

    Full Text Available DNA damage is a pre-requisite for the initiation of cancer and agents that reduce this damage are useful in cancer prevention. In this study, we evaluated the ability of whole berries and berry phytochemical, ellagic acid to reduce endogenous oxidative DNA damage. Ellagic acid was selected based on > 95% inhibition of 8-oxodeoxyguosine (8-oxodG and other unidentified oxidative DNA adducts induced by 4-hydroxy-17B;-estradiol and CuCl2 in vitro. Inhibition of the latter occurred at lower concentrations (10 u(microM than that for 8-oxodG (100 u(microM. In the in vivo study, female CD-1 mice (n=6 were fed either a control diet or diet supplemented with ellagic acid (400 ppm and dehydrated berries (5% w/w with varying ellagic acid contents -- blueberry (low, strawberry (medium and red raspberry (high, for 3 weeks. Blueberry and strawberry diets showed moderate reductions in endogenous DNA adducts (25%. However, both red raspberry and ellagic acid diets showed a significant reduction of 59% (p < 0.001 and 48% (p < 0.01, respectively. Both diets also resulted in a 3-8 fold over-expression of genes involved in DNA repair such as xeroderma pigmentosum group A complementing protein (XPA, DNA excision repair protein (ERCC5 and DNA ligase III (DNL3. These results suggest that red raspberry and ellagic acid reduce endogenous oxidative DNA damage by mechanisms which may involve increase in DNA repair.

  5. Repair of Damaged M-Chromium-Aluminum-Yttrium Coatings Targeting Petroleum Industry Applications

    Science.gov (United States)

    Farhat, Rabab

    The increase in efficiency of furnace and refinery components in petroleum industries has been the target of many studies. However, the repair technology for damaged pieces is still to be developed. During prolonged service, a degradation of developed coatings occurs as a result of the harsh environment. Therefore, a repair technology, which can extend the life of the coatings, is now under consideration. In this work, electrospark deposition (ESD) has been investigated to understand the solidification behavior and its possibility to repair damaged MCrAlY coatings. Ni-based alloys with different compositions were deposited on Ni substrate using ESD to understand crystal structure of the solidified deposit and the effect of the dissimilar weld composition on dilution. The electrode samples were prepared by spark plasma sintering (SPS). Firstly, different coatings with single and bi-phase microstructure were deposited on pure Ni substrate. Secondly, NiCoCrAlY and CoNiCrAlY were deposited on the damaged spot of the oxidized NiCoCrAlY and CoNiCrAlY respectively. A fine microstructure of metastable phases obtained from each deposit. Also, it was found that an epitaxial growth of NiCoCrAlY and CoNiCrAlY were obtained on the damaged spots. In addition, α-Al 2O3 was obtained on the surface of the deposit after 24hr oxidation at 1000°C.

  6. Incident laser modulation of a repaired damage site with a rim in fused silica rear subsurface

    Institute of Scientific and Technical Information of China (English)

    Li Li; Xiang Xia; Zu Xiao-Tao; Yuan Xiao-Dong; He Shao-Bo; Jiang Xiao-Dong; Zheng Wan-Guo

    2012-01-01

    Local CO2 laser treatment has proved to be an effective method to prevent the 351-nm laser-induced damage sitesin a fused silica surface from exponentially growing,which is responsible for limiting the lifetime of optics in high fluence laser systems.However,the CO2 laser induced ablation crater is often surrounded by a raised rim at the edge,which can also result in the intensification of transmitted ultraviolet light that may damage the downstream optics.In this work,the three-dimensional finite-difference time-domain method is developed to simulate the distribution of electrical field intensity in the vicinity of the CO2 laser mitigated damage site located in the exit subsurface of fused silica.The simulated results show that the repaired damage sites with raised rims cause more notable modulation to the incident laser than those without rims.Specifically,we present a theoretical model of using dimpled patterning to control the rim structure around the edge of repaired damage sites to avoid damage to downstream optics.The calculated results accord well with previous experimental results and the underlying physical mechanism is analysed in detail.

  7. Regulators of global genome repair do not respond to DNA damaging therapy but correlate with survival in melanoma.

    Directory of Open Access Journals (Sweden)

    Nikola A Bowden

    Full Text Available Nucleotide excision repair (NER orchestrates the repair of helix distorting DNA damage, induced by both ultraviolet radiation (UVR and cisplatin. There is evidence that the global genome repair (GGR arm of NER is dysfunctional in melanoma and it is known to have limited induction in melanoma cell lines after cisplatin treatment. The aims of this study were to examine mRNA transcript levels of regulators of GGR and to investigate the downstream effect on global transcript expression in melanoma cell lines after cisplatin treatment and in melanoma tumours. The GGR regulators, BRCA1 and PCNA, were induced in melanocytes after cisplatin, but not in melanoma cell lines. Transcripts associated with BRCA1, BRCA2, ATM and CHEK2 showed altered expression in melanoma cell lines after cisplatin treatment. In melanoma tumour tissue BRCA1 transcript expression correlated with poor survival and XPB expression correlated with solar elastosis levels. Taken together, these findings provide evidence of the mechanisms underlying NER deficiency in melanoma.

  8. Radiosensitivity and capacity for radiation-induced sublethal damage repair of canine transitional cell carcinoma (TCC) cell lines.

    Science.gov (United States)

    Parfitt, S L; Milner, R J; Salute, M E; Hintenlang, D E; Farese, J P; Bacon, N J; Bova, F J; Rajon, D A; Lurie, D M

    2011-09-01

    Understanding the inherent radiosensitivity and repair capacity of canine transitional cell carcinoma (TCC) can aid in optimizing radiation protocols to treat this disease. The objective of this study was to evaluate the parameters surviving fraction at 2 Gy (SF(2) ), α/β ratio and capacity for sublethal damage repair (SLDR) in response to radiation. Dose-response and split-dose studies were performed using the clonogenic assay. The mean SF(2) for three established TCC cell lines was high at 0.61. All the three cell lines exhibited a low to moderate α/β ratio, with the mean being 3.27. Two cell lines exhibited statistically increased survival at 4 and 24 h in the dose-response assay. Overall, our results indicate that the cell lines are moderately radioresistant, have a high repair capacity and behave similarly to a late-responding normal tissue. These findings indicate that the radiation protocols utilizing higher doses with less fractionation may be more effective for treating TCC.

  9. DNA damage induction and/or repair as mammalian cell biomarker for the prediction of cellular radiation response

    Science.gov (United States)

    Baumstark-Khan, C.

    DNA damage and its repair processes are key factors in cancer induction and also in the treatment of malignancies. Cancer prevention during extended space missions becomes a topic of great importance for space radiobiology. The knowledge of individual responsiveness would allow the protection strategy to be tailored optimally in each case. Radiobiological analysis of cultured cells derived from tissue explants from individuals has shown that measurement of the surviving fraction after 2 Gy (SF2) may be used to predict the individual responsiveness. However, clonogenic assays are timeconsuming, thus alternative assays for the determination of radiore-sponse are being sought. For that reason CHO cell strains having different repair capacities were used for examining whether DNA strand break repair is a suitable experimental design to allow predictive statements. Cellular survival (CFA assay) and DNA strand breaks (total DNA strand breaks: FADU technique; DSBs: non-denaturing elution) were determined in parallel immediately after irradiation as well as after a 24 hour recovery period according to dose. There were no correlations between the dose-response curves of the initial level of DNA strand breaks and parameters that describe clonogenic survival curves (SF2). A good correlation exists between intrinsic cellular radioresistance and the extent of residual DNA strand breaks.

  10. Rad54 and Mus81 cooperation promotes DNA damage repair and restrains chromosome missegregation

    DEFF Research Database (Denmark)

    Ghamrasni, S El; Cardoso, R; Li, L;

    2016-01-01

    Rad54 and Mus81 mammalian proteins physically interact and are important for the homologous recombination DNA repair pathway; however, their functional interactions in vivo are poorly defined. Here, we show that combinatorial loss of Rad54 and Mus81 results in hypersensitivity to DNA......-damaging agents, defects on both the homologous recombination and non-homologous DNA end joining repair pathways and reduced fertility. We also observed that while Mus81 deficiency diminished the cleavage of common fragile sites, very strikingly, Rad54 loss impaired this cleavage to even a greater extent....... The inefficient repair of DNA double-strand breaks (DSBs) in Rad54(-/-)Mus81(-/-) cells was accompanied by elevated levels of chromosome missegregation and cell death. Perhaps as a consequence, tumor incidence in Rad54(-/-)Mus81(-/-) mice remained comparable to that in Mus81(-/-) mice. Our study highlights...

  11. [Studies of the repair of radiation-induced genetic damage in Drosophila]. Annual progress report, October 1, 1988--June 1, 1989

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1989-12-31

    The primary goal of this study is to achieve a more thorough understanding of the mechanisms employed by higher organisms to repair DNA damage induced by both ionizing and nonionizing radiation. These studies are also contributing to an improved understanding of the processes of mutagenesis and carcinogenesis in higher eukaryotes. The studies employ Drosophila as a model organism for investigating repair functions that are common to all higher eukaryotes. Drosophila was chosen in the early phases of this study primarily because of the ease with which one can isolate and characterize repair-deficient mutants in a metazoan organism. The laboratory has gone on to investigate the metabolic defects of such mutants while others have performed complementary genetic and cytogenetic studies which relate DNA repair processes to mutagenesis and chromosome stability. The repair studies have exploited the capacity to introduce mutant Drosophila cells into tissue culture and thereby compare repair defects directly with those of homologous human disorders. Researchers are currently employing recombinant DNA technology to investigate the mechanisms of the DNA repair pathways defined by those mutants.

  12. Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage

    NARCIS (Netherlands)

    Rutgers, M.; van Pelt, M.J.; Dhert, W.J.A.; Creemers, L.B.; Saris, D.B.F.

    2010-01-01

    Osteoarthritis and Cartilage Volume 18, Issue 1, January 2010, Pages 12-23 -------------------------------------------------------------------------------- Review Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage M. Rutgers†, M.J.P. van Pelt†, W.

  13. Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage

    NARCIS (Netherlands)

    Rutgers, M.; van Pelt, M.J.; Dhert, W.J.A.; Creemers, L.B.; Saris, D.B.F.

    2010-01-01

    Osteoarthritis and Cartilage Volume 18, Issue 1, January 2010, Pages 12-23 -------------------------------------------------------------------------------- Review Evaluation of histological scoring systems for tissue-engineered, repaired and osteoarthritic cartilage M. Rutgers†, M.J.P. van Pelt†,

  14. Evaluation of radioinduced damage and repair capacity in blood lymphocytes of breast cancer patients

    Directory of Open Access Journals (Sweden)

    P.A. Nascimento

    2001-02-01

    Full Text Available Genetic damage caused by ionizing radiation and repair capacity of blood lymphocytes from 3 breast cancer patients and 3 healthy donors were investigated using the comet assay. The comets were analyzed by two parameters: comet tail length and visual classification. Blood samples from the donors were irradiated in vitro with a 60Co source at a dose rate of 0.722 Gy/min, with a dose range of 0.2 to 4.0 Gy and analyzed immediately after the procedure and 3 and 24 h later. The basal level of damage and the radioinduced damage were higher in lymphocytes from breast cancer patients than in lymphocytes from healthy donors. The radioinduced damage showed that the two groups had a similar response when analyzed immediately after the irradiations. Therefore, while the healthy donors presented a considerable reduction of damage after 3 h, the patients had a higher residual damage even 24 h after exposure. The repair capacity of blood lymphocytes from the patients was slower than that of lymphocytes from healthy donors. The possible influence of age, disease stage and mutations in the BRCA1 and BRCA2 genes are discussed. Both parameters adopted proved to be sensitive and reproducible: the dose-response curves for DNA migration can be used not only for the analysis of cellular response but also for monitoring therapeutic interventions. Lymphocytes from the breast cancer patients presented an initial radiosensitivity similar to that of healthy subjects but a deficient repair mechanism made them more vulnerable to the genotoxic action of ionizing radiation. However, since lymphocytes from only 3 patients and 3 normal subjects were analyzed in the present paper, additional donors will be necessary for a more accurate evaluation.

  15. Repair work continues on the external tank of Space Shuttle Discovery after damage from hail

    Science.gov (United States)

    1999-01-01

    In the Vehicle Assembly Building (VAB), United Space Alliance technician Robert Williams sands the repaired areas near the top of Space Shuttle Discovery's external tank. Repairs were required for damage caused by hail during recent storms. Because access to all of the damaged areas was not possible at the pad, the Shuttle was rolled back from Pad 39B to the VAB. The work is expected to take two to three days, allowing Discovery to roll back to the pad late this week for launch of mission STS-96, the 94th launch in the Space Shuttle Program. Liftoff will occur no earlier than May 27. STS-96 is a logistics and resupply mission for the International Space Station, carrying such payloads as a Russian crane, the Strela; a U.S.-built crane; the Spacehab Oceaneering Space System Box (SHOSS), a logistics items carrier; and STARSHINE, a student-shared experiment.

  16. Arsenic Biotransformation as a Cancer Promoting Factor by Inducing DNA Damage and Disruption of Repair Mechanisms

    Directory of Open Access Journals (Sweden)

    Victor D. Martinez

    2011-01-01

    Full Text Available Chronic exposure to arsenic in drinking water poses a major global health concern. Populations exposed to high concentrations of arsenic-contaminated drinking water suffer serious health consequences, including alarming cancer incidence and death rates. Arsenic is biotransformed through sequential addition of methyl groups, acquired from s-adenosylmethionine (SAM. Metabolism of arsenic generates a variety of genotoxic and cytotoxic species, damaging DNA directly and indirectly, through the generation of reactive oxidative species and induction of DNA adducts, strand breaks and cross links, and inhibition of the DNA repair process itself. Since SAM is the methyl group donor used by DNA methyltransferases to maintain normal epigenetic patterns in all human cells, arsenic is also postulated to affect maintenance of normal DNA methylation patterns, chromatin structure, and genomic stability. The biological processes underlying the cancer promoting factors of arsenic metabolism, related to DNA damage and repair, will be discussed here.

  17. Increasing Melanoma—Too Many Skin Cell Damages or Too Few Repairs?

    Directory of Open Access Journals (Sweden)

    Örjan Hallberg

    2013-02-01

    Full Text Available Skin melanoma rates have been increasing for a long time in many Western countries. The object of this study was to apply modern problem-solving theory normally used to clear industrial problems to search for roots and causes of this medical question. Increasing cancer rates can be due to too many cell damage incidents or to too few repairs. So far, it has been assumed that the melanoma epidemic mainly is caused by increasing sun tanning habits. In order to explore this problem in more detail, we used cancer statistics from several countries over time and space. Detailed analysis of data obtained and a model study to evaluate the effects from increased damages or decreased repairs clearly indicate that the main reason behind the melanoma problem is a disturbed immune system. The possibility to introduce efficient corrective actions is apparent.

  18. Oxidatively damaged DNA and its repair after experimental exposure to wood smoke in healthy humans

    DEFF Research Database (Denmark)

    Danielsen, Pernille Høgh; Bräuner, Elvira Vaclavik; Barregard, Lars

    2008-01-01

    Particulate matter from wood smoke may cause health effects through generation of oxidative stress with resulting damage to DNA. We investigated oxidatively damaged DNA and related repair capacity in peripheral blood mononuclear cells (PBMC) and measured the urinary excretion of repair products...... after controlled short-term exposure of human volunteers to wood smoke. Thirteen healthy adults were exposed first to clean air and then to wood smoke in a chamber during 4h sessions, 1 week apart. Blood samples were taken 3h after exposure and on the following morning, and urine was collected after...... chromatography with mass spectrometry. The morning following exposure to wood smoke the PBMC levels of SB were significantly decreased and the mRNA levels of hOGG1 significantly increased. FPG sites, hOGG1 activity, expression of hNUDT1 and hHO1, urinary excretion of 8-oxodG and 8-oxoGua did not change...

  19. Granular Effect of Fly Ash Repairs Damage of Recycled Coarse Aggregate

    Institute of Scientific and Technical Information of China (English)

    LI Jiu-su; XIAO Han-ning; GONG Jian-qing

    2008-01-01

    Repairing effect of fly ash (FA) on damage of recycled coarse aggregate was evaluated by characteristics of pores and cracks in the vicinity of interracial transition zone (ITZ). The interracial structure between the virgin aggregate and the attached old mortar was investigated and compared with ITZ of recycled aggregate concrete in the presence of FA or ultra-fine FA(UFA) by means of scanning electron microscope (SEM). Diam- eter and plumpness frequency distribution of pores as well as width of the old ITZ, length of contacting points and cracks density were analyzed. The SEM results reveal that the diameter of pores is decreases significantly but pores plumpness increases. A decreased ITZ width and cracks density as well as an increased bonding zone length can also been observed, which indicates that FA or UFA repairs damage of recycled coarse aggregate due to its granular effect.

  20. Rotator Interval Lesion and Damaged Subscapularis Tendon Repair in a High School Baseball Player

    Directory of Open Access Journals (Sweden)

    Tomoyuki Muto

    2015-01-01

    Full Text Available In 2013, a 16-year-old baseball pitcher visited Nobuhara Hospital complaining of shoulder pain and limited range of motion in his throwing shoulder. High signal intensity in the rotator interval (RI area (ball sign, injured subscapularis tendon, and damage to both the superior and middle glenohumeral ligaments were identified using magnetic resonance imaging (MRI. Repair of the RI lesion and partially damaged subscapularis tendon was performed in this pitcher. During surgery, an opened RI and dropping of the subscapularis tendon were observed. The RI was closed in a 90° externally rotated and abducted position. To reconfirm the exact repaired state of the patient, arthroscopic examination was performed from behind. However, suture points were not visible in the >30° externally rotated position, which indicates that the RI could not be correctly repaired with the arthroscopic procedure. One year after surgery, the patient obtained full function of the shoulder and returned to play at a national convention. Surgical repair of the RI lesion should be performed in exactly the correct position of the upper extremity.

  1. Repair of damage to wind turbine foundations. Nondestructive ultrasonic testing; Sanierung von Fundamentschaeden. Zerstoerungsfreie Pruefung mittels Ultraschall

    Energy Technology Data Exchange (ETDEWEB)

    Zimmer, Hans-Peter [CONCRETE CARE, Berlin (Germany)

    2009-07-01

    Damage of foundations is often not visible from the surface. And even visible cracks do not show how far they reach inside the foundation. Prior to any repair measures, detailed analysis and a careful and precise description of the damage pattern are required. The biggest challenge is the detection of hidden damage and its correct description. Nondestructive methods are the method of choice. (orig.)

  2. DNA Damage Response and DNA Repair in Skeletal Myocytes From a Mouse Model of Spinal Muscular Atrophy.

    Science.gov (United States)

    Fayzullina, Saniya; Martin, Lee J

    2016-09-01

    We studied DNA damage response (DDR) and DNA repair capacities of skeletal muscle cells from a mouse model of infantile spinal muscular atrophy (SMA) caused by loss-of-function mutation of survival of motor neuron (Smn). Primary myocyte cultures derived from skeletal muscle satellite cells of neonatal control and mutant SMN mice had similar myotube length, myonuclei, satellite cell marker Pax7 and differentiated myotube marker myosin, and acetylcholine receptor clustering. DNA damage was induced in differentiated skeletal myotubes by γ-irradiation, etoposide, and methyl methanesulfonate (MMS). Unexposed control and SMA myotubes had stable genome integrity. After γ-irradiation and etoposide, myotubes repaired most DNA damage equally. Control and mutant myotubes exposed to MMS exhibited equivalent DNA damage without repair. Control and SMA myotube nuclei contained DDR proteins phospho-p53 and phospho-H2AX foci that, with DNA damage, dispersed and then re-formed similarly after recovery. We conclude that mouse primary satellite cell-derived myotubes effectively respond to and repair DNA strand-breaks, while DNA alkylation repair is underrepresented. Morphological differentiation, genome stability, genome sensor, and DNA strand-break repair potential are preserved in mouse SMA myocytes; thus, reduced SMN does not interfere with myocyte differentiation, genome integrity, and DNA repair, and faulty DNA repair is unlikely pathogenic in SMA.

  3. Low velocity impact response and damage evolution in unreinforced resin systems and self-repairing polymer matrix composites

    Science.gov (United States)

    Motuku, Molefi

    The low velocity impact response and damage evolution in unreinforced polymer matrices, conventional polymer matrix composites, and self-repairing polymer matrix composites was investigated. The impact response study of unreinforced matrices and conventional laminates was undertaken because the failure initiation energies, threshold energy levels, failure characteristics and damage evolution in both the matrix material (unreinforced resin plaques) and the composite are intrinsic to proper design of a self-repairing composite. The self-repairing concept was investigated due to its attractive potential to alleviate damage problems in polymer matrix composites. Self-repairing composites, which fall under the category of passive smart polymer composites, have the potential to self repair both micro- and macro-damage resulting from impacts as well as non-impact loading. The self-repairing mechanism is achieved through the incorporation of hollow fibers in addition to the normal solid reinforcing fibers. The hollow fibers store the damage-repairing solution or chemicals that are released into the matrix or damaged zone upon fiber failure to repair and/or arrest damage progression. The room temperature low velocity impact response and damage evolution in DERAKANE 411-350 and 411-C50 vinyl ester unreinforced resin systems was investigated as a function of impact energy level, sample thickness, matrix material and catalyst system. The low velocity impact response of conventional and self-repairing glass reinforced polymer composites was investigated by addressing the fabrication and some of the parameters that influence their response to low velocity impact loading. Specific issues addressed by this study include developing a process to fabricate self-repairing laminates, processing quality; selection of storage material for the repairing solution; release and transportation of repairing solution; the effect of the number, type and spatial distribution of the repairing

  4. 膝关节周围皮肤软组织缺损的修复%Repair of skin and soft tissue defects around the knee joints

    Institute of Scientific and Technical Information of China (English)

    谭谦; 许澎

    2015-01-01

    Skin and soft tissue defects around the knee joints are often accompanied by popliteal artery injury, patellar ligament injury, patellar fracture, and other deep tissue damage or exposure, making them challenging to repair.The principle is to repair the wound, reconstruct anatomical structure of the knee joint, and recover the knee joint function.At present the reconstruction with skin flap or myocutaneous flap is our priority.Local flap or myocutaneous flap can be used for repairing minor defects around the knee joints.Repairing with perforator flap, fascia flap, and free flap are main alternatives for covering larger and complex defects around the knee joints.During the treatment, a joint effort is mandatory, not only to repair the wound, but also to reconstruct vasculature, fix fracture, repair ligament, and finally recover the knee joint function.Therefore, the importance of multidisciplinary cooperation must be emphasized.Moreover, along with the development of new technologies, new methods, and new materials, perforator flap plays an important role in repairing skin and soft tissue defects around the knee joints.

  5. Maintaining Genetic Integrity Under Extreme Conditions: Novel DNA Damage Repair Biology in the Archaea

    Science.gov (United States)

    2013-11-23

    DeRuggiero (Johns Hopkins University). Chromosome behaviour was monitored in wild-type and ∆nreA cells treated with MMC for 1 hour and during a 10...MacNeill, undergraduate students Agnieszka Janska and Jason Woodier) In bacteria , RecJ has an important role in DNA damage repair, in particular in...is an NAD-dependent enzyme the gene for which was apparently acquired by lateral gene transfer from bacteria . Biochemical analysis of LigN function

  6. Human POLD1 modulates cell cycle progression and DNA damage repair

    OpenAIRE

    Song, Jing; Hong, Ping; Liu, Chengeng; Zhang, Yueqi; Wang, Jinling; Wang, Peichang

    2015-01-01

    Background The activity of eukaryotic DNA polymerase delta (Pol ?) plays an essential role in genome stability through its effects on DNA replication and repair. The p125 catalytic subunit of Pol ? is encoded by POLD1 gene in human cells. To clarify biological functions of POLD1, we investigated the effects of POLD1 overexpression or downregulation on cell proliferation, cell cycle progression, DNA synthesis and oxidative DNA damage induced by H2O2. Methods HEK293 cells were transfected with ...

  7. Systemic inflammation regulates microglial responses to tissue damage in vivo

    Science.gov (United States)

    Gyoneva, Stefka; Davalos, Dimitrios; Biswas, Dipankar; Swanger, Sharon A.; Garnier-Amblard, Ethel; Loth, Francis; Akassoglou, Katerina; Traynelis, Stephen F.

    2015-01-01

    Microglia, the resident immune cells of the central nervous system, exist in either a “resting” state associated with physiological tissue surveillance or an “activated” state in neuroinflammation. We recently showed that ATP is the primary chemoattractor to tissue damage in vivo and elicits opposite effects on the motility of activated microglia in vitro through activation of adenosine A2A receptors. However, whether systemic inflammation affects microglial responses to tissue damage in vivo remains largely unknown. Using in vivo two-photon imaging of mice, we show that injection of lipopolysaccharide (LPS) at levels that can produce both clear neuroinflammation and some features of sepsis significantly reduced the rate of microglial response to laser-induced ablation injury in vivo. Under pro-inflammatory conditions, microglial processes initially retracted from the ablation site, but subsequently moved toward and engulfed the damaged area. Analyzing the process dynamics in 3D cultures of primary microglia indicated that only A2A, but not A1 or A3 receptors, mediate process retraction in LPS-activated microglia. The A2A receptor antagonists caffeine and preladenant reduced adenosine-mediated process retraction in activated microglia in vitro. Finally, administration of preladenant before induction of laser ablation in vivo accelerated the microglial response to injury following systemic inflammation. The regulation of rapid microglial responses to sites of injury by A2A receptors could have implications for their ability to respond to the neuronal death occurring under conditions of neuroinflammation in neurodegenerative disorders. PMID:24807189

  8. DNA Damage and Repair in Plants under Ultraviolet and Ionizing Radiations

    Directory of Open Access Journals (Sweden)

    Sarvajeet S. Gill

    2015-01-01

    Full Text Available Being sessile, plants are continuously exposed to DNA-damaging agents present in the environment such as ultraviolet (UV and ionizing radiations (IR. Sunlight acts as an energy source for photosynthetic plants; hence, avoidance of UV radiations (namely, UV-A, 315–400 nm; UV-B, 280–315 nm; and UV-C, <280 nm is unpreventable. DNA in particular strongly absorbs UV-B; therefore, it is the most important target for UV-B induced damage. On the other hand, IR causes water radiolysis, which generates highly reactive hydroxyl radicals (OH• and causes radiogenic damage to important cellular components. However, to maintain genomic integrity under UV/IR exposure, plants make use of several DNA repair mechanisms. In the light of recent breakthrough, the current minireview (a introduces UV/IR and overviews UV/IR-mediated DNA damage products and (b critically discusses the biochemistry and genetics of major pathways responsible for the repair of UV/IR-accrued DNA damage. The outcome of the discussion may be helpful in devising future research in the current context.

  9. Influence of LET on repair of DNA damages in Deinococcus radiodurans

    Energy Technology Data Exchange (ETDEWEB)

    Kobayashi, Y.; Tanaka, A.; Kikuchi, M.; Shimizu, T.; Watanabe, H. [Japan Atomic Energy Research Inst., Takasaki, Gunma (Japan). Takasaki Radiation Chemistry Research Establishment; Cao, J.P.; Taucher-Scholz, G.

    1997-03-01

    Inactivation caused by heavy ions was studied in dry cells of radioresistant bacterium Deinococcus radiodurans. All survival curves were characterized by a large shoulder of the curves. No final slopes of the exponential part of survival curves for heavy ion irradiation were steeper than that for 2.0 MeV electron irradiation. The plots of RBE versus LET showed no obvious peaks, suggesting that this bacterium can repair not only DNA double strand breaks (DSBs) but also clustered damage in DNA which may be induced by heavy ions. The genomic DNA of D. radiodurans was cleaved into large fragments with restriction enzyme Not I after post-irradiation incubation and the fragments were separated using pulsed-field gel electrophoresis (PFGE). DSBs induction and rejoining process were analyzed by detection of the reappearance of ladder pattern of DNA fragments. The required repair time after heavy ions irradiation was longer than the repair time for electrons at the same dose of irradiation, however, the rate of repair enzyme induction was almost similar to each other between electrons and heavy ions, suggesting that the same repair system is likely to be used after both low and high LET irradiations. (author)

  10. DNA damage and repair in white blood cells at occupational exposure

    Energy Technology Data Exchange (ETDEWEB)

    Georgieva, R T; Zaharieva, E K; Rupova, I M; Acheva, A R; Nikolov, V N [Department of Radiobiology, National Center of Radiobiology and Radiation Protection, Sofia, 1756 (Bulgaria)], E-mail: r.georgieva@ncrrp.org

    2008-02-01

    : The present work was aimed at finding appropriate biomarkers applicable in molecular epidemiological surveys of occupationally exposed individuals and/or population in order to prove low dose effects. Blood samples were taken from NPP workers, in the 'strict regimen' area (exposed group) and from the administration staff (control group). The spontaneous and induced (exposed to a challenge dose of 2,0 Gy gamma irradiation) DNA repair synthesis in leucocytes, the level of DNA damage by single cell gel-electrophoresis in lymphocytes and the concentration of malonedialdehyde in blood serum, were analyzed. A significant decrease of potentially lethal damage in leucocytes as well as reduction of DNA double strand breaks level in lymphocytes of persons with 'mean annual dose' lower or equal to 5 mSv/a was found, compared to the control group. A higher repair capacity corresponding to elevated protein synthesis after a challenging dose of 2,0 Gy gamma rays and a significant decrease in the level of oxidative stress in the blood plasma were established in persons from the same group. The present investigation showed that annual doses not higher than twice the natural radiation background exert positive effects on DNA damage and repair, increase cellular resistance and decrease oxidative stress.

  11. Modeling damage complexity-dependent non-homologous end-joining repair pathway.

    Directory of Open Access Journals (Sweden)

    Yongfeng Li

    Full Text Available Non-homologous end joining (NHEJ is the dominant DNA double strand break (DSB repair pathway and involves several repair proteins such as Ku, DNA-PKcs, and XRCC4. It has been experimentally shown that the choice of NHEJ proteins is determined by the complexity of DSB. In this paper, we built a mathematical model, based on published data, to study how NHEJ depends on the damage complexity. Under an appropriate set of parameters obtained by minimization technique, we can simulate the kinetics of foci track formation in fluorescently tagged mammalian cells, Ku80-EGFP and DNA-PKcs-YFP for simple and complex DSB repair, respectively, in good agreement with the published experimental data, supporting the notion that simple DSB undergo fast repair in a Ku-dependent, DNA-PKcs-independent manner, while complex DSB repair requires additional DNA-PKcs for end processing, resulting in its slow repair, additionally resulting in slower release rate of Ku and the joining rate of complex DNA ends. Based on the numerous experimental descriptions, we investigated several models to describe the kinetics for complex DSB repair. An important prediction of our model is that the rejoining of complex DSBs is through a process of synapsis formation, similar to a second order reaction between ends, rather than first order break filling/joining. The synapsis formation (SF model allows for diffusion of ends before the synapsis formation, which is precluded in the first order model by the rapid coupling of ends. Therefore, the SF model also predicts the higher number of chromosomal aberrations observed with high linear energy transfer (LET radiation due to the higher proportion of complex DSBs compared to low LET radiation, and an increased probability of misrejoin following diffusion before the synapsis is formed, while the first order model does not provide a mechanism for the increased effectiveness in chromosomal aberrations observed.

  12. Repairing articular cartilage defects with tissue-engineering cartilage in rabbits

    Institute of Scientific and Technical Information of China (English)

    SONG Hong-xing; LI Fo-bao; SHEN Hui-liang; LIAO Wei-ming; LIU Miao; WANG Min; CAO Jun-ling

    2006-01-01

    Objective: To investigate the effect of cancellous bone matrix gelatin (BMG) engineered with allogeneic chondrocytes in repairing articular cartilage defects in rabbits.Methods: Chondrocytes were seeded onto three-dimensional cancellous BMG and cultured in vitro for 12 days to prepare BMG-chondrocyte complexes. Under anesthesia with 2.5% pentobarbital sodium (1 ml/kg body weight), articular cartilage defects were made on the right knee joints of 38 healthy New Zealand white rabbits (regardless of sex, aged 4-5 months and weighing 2.5-3 kg) and the defects were then treated with 2.5 % trypsin.Then BMG-chondrocyte complex (Group A, n=18 ),BMG ( Group B, n=10), and nothing ( Group C, n=10)were implanted into the cartilage defects, respectively. The repairing effects were assessed by macroscopic, histologic,transmission electron microscopic (TEM) observation,immunohistochemical examination and in situ hybridization detection, respectively, at 2, 4, 8, 12 and 24 weeks after operation.Results: Cancellous BMG was degraded within 8 weeks after operation. In Group A, lymphocyte infiltration was observed around the graft. At 24 weeks after operation, the cartilage defects were repaired by cartilage tissues and the articular cartilage and subchondral bone were soundly healed. Proteoglycan and type Ⅱ collagen were detected in the matrix of the repaired tissues by Safranin-O staining and immunohistochemical staining,respectively. In situ hybridization proved gene expression of type Ⅱ collagen in the cytoplasm of chondrocytes in the repaired tissues. TEM observation showed that chondrocytes and cartilage matrix in repaired tissues were almost same as those in the normal articular cartilage. In Group B, the defects were repaired by cartilage-fibrous tissues. In Group C, the defects were repaired only by fibrous tissues.Conclusions : Cancellous BMG can be regarded as the natural cell scaffolds for cartilage tissue engineering.Articular cartilage defects can be repaired by

  13. Comparative DNA damage and repair in echinoderm coelomocytes exposed to genotoxicants.

    Science.gov (United States)

    El-Bibany, Ameena H; Bodnar, Andrea G; Reinardy, Helena C

    2014-01-01

    The capacity to withstand and repair DNA damage differs among species and plays a role in determining an organism's resistance to genotoxicity, life history, and susceptibility to disease. Environmental stressors that affect organisms at the genetic level are of particular concern in ecotoxicology due to the potential for chronic effects and trans-generational impacts on populations. Echinoderms are valuable organisms to study the relationship between DNA repair and resistance to genotoxic stress due to their history and use as ecotoxicological models, little evidence of senescence, and few reported cases of neoplasia. Coelomocytes (immune cells) have been proposed to serve as sensitive bioindicators of environmental stress and are often used to assess genotoxicity; however, little is known about how coelomocytes from different echinoderm species respond to genotoxic stress. In this study, DNA damage was assessed (by Fast Micromethod) in coelomocytes of four echinoderm species (sea urchins Lytechinus variegatus, Echinometra lucunter lucunter, and Tripneustes ventricosus, and a sea cucumber Isostichopus badionotus) after acute exposure to H2O2 (0-100 mM) and UV-C (0-9999 J/m2), and DNA repair was analyzed over a 24-hour period of recovery. Results show that coelomocytes from all four echinoderm species have the capacity to repair both UV-C and H2O2-induced DNA damage; however, there were differences in repair capacity between species. At 24 hours following exposure to the highest concentration of H2O2 (100 mM) and highest dose of UV-C (9999 J/m2) cell viability remained high (>94.6 ± 1.2%) but DNA repair ranged from 18.2 ± 9.2% to 70.8 ± 16.0% for H2O2 and 8.4 ± 3.2% to 79.8 ± 9.0% for UV-C exposure. Species-specific differences in genotoxic susceptibility and capacity for DNA repair are important to consider when evaluating ecogenotoxicological model organisms and assessing overall impacts of genotoxicants in the environment.

  14. Comparative DNA damage and repair in echinoderm coelomocytes exposed to genotoxicants.

    Directory of Open Access Journals (Sweden)

    Ameena H El-Bibany

    Full Text Available The capacity to withstand and repair DNA damage differs among species and plays a role in determining an organism's resistance to genotoxicity, life history, and susceptibility to disease. Environmental stressors that affect organisms at the genetic level are of particular concern in ecotoxicology due to the potential for chronic effects and trans-generational impacts on populations. Echinoderms are valuable organisms to study the relationship between DNA repair and resistance to genotoxic stress due to their history and use as ecotoxicological models, little evidence of senescence, and few reported cases of neoplasia. Coelomocytes (immune cells have been proposed to serve as sensitive bioindicators of environmental stress and are often used to assess genotoxicity; however, little is known about how coelomocytes from different echinoderm species respond to genotoxic stress. In this study, DNA damage was assessed (by Fast Micromethod in coelomocytes of four echinoderm species (sea urchins Lytechinus variegatus, Echinometra lucunter lucunter, and Tripneustes ventricosus, and a sea cucumber Isostichopus badionotus after acute exposure to H2O2 (0-100 mM and UV-C (0-9999 J/m2, and DNA repair was analyzed over a 24-hour period of recovery. Results show that coelomocytes from all four echinoderm species have the capacity to repair both UV-C and H2O2-induced DNA damage; however, there were differences in repair capacity between species. At 24 hours following exposure to the highest concentration of H2O2 (100 mM and highest dose of UV-C (9999 J/m2 cell viability remained high (>94.6 ± 1.2% but DNA repair ranged from 18.2 ± 9.2% to 70.8 ± 16.0% for H2O2 and 8.4 ± 3.2% to 79.8 ± 9.0% for UV-C exposure. Species-specific differences in genotoxic susceptibility and capacity for DNA repair are important to consider when evaluating ecogenotoxicological model organisms and assessing overall impacts of genotoxicants in the environment.

  15. 肢体创伤性软组织缺损修复面面观%General view on the repair of traumatic soft tissue defects of extremities

    Institute of Scientific and Technical Information of China (English)

    柴益民; 陆晟迪; 曾炳芳

    2015-01-01

    Repir of soft tissue defects takes an important role in the ifeld of traumatic repairative surgery, including repair of the injuries and accidents resulted acute wounds, reconstruction for chronic wounds caused by diabetes and vascular diseases, salvage and functional reconstruction of the injured limbs. The repair of traumatic soft tissue defects of the extremities needs overall considerations on the evaluation, methods, principle, decision making and timing. The evaluation consists of the local condition of the injured limb, as well as the general condition, expectation value to the treatment, and the economic and psychological endurance capacity to the multiple reconstructive operations of the patients. Clinically available methods include VAC ( vacuum assisted closure ) technique, skin substitutes, skin graft, plasty of local skin lfap, skin expender, pedicled transposition or transplantation of axial tissue lfaps, neurofasciocutaneous or perforator lfaps. The principles of repair of soft tissue defects are to use the like tissues to repair the defects, to reduce the damage to the donor sites, to reach the goals in both the functional and cosmetic outcome, to plan the operation carefully and comprehensively. The decision making can be done following the concept of “reconstruction ladder”, by which the surgical procedures are selected gradually from “the simple” to “the complex”. However, with the advanced technique in hands, the surgeons may start with “the best” rather than “the simplest” to repair the soft tissue defects, as long as it is indicated no matter how dififcult it might be. As to the timing, the soft tissue defect is repaired the earlier the better, of cause safety and effectiveness are the prerequisite to do this. A successful microsurgical repair can make full use of the tissues spared from the injury to save the injured limb and to reconstruct its function thus to shorten the treatment process, to relieve the pain of the

  16. Thermal spray and weld repair alloys for the repair of cavitation damage in turbines and pumps: A technical note

    Science.gov (United States)

    Kumar, Ashok; Boy, J.; Zatorski, Ray; Stephenson, L. D.

    2005-06-01

    The cavitation and erosion resistance of 21 thermal spray coatings and four weld repair materials were investigated in the laboratory using cavitation jet and slurry erosion testing. Of the thermal spray coatings, Stellite® 6 deposited by the high velocity oxyfuel (HVOF) process had the lowest cavitation rate (11.7 mg/h). This was higher than the corresponding cavitation rate (3.2 mg/h) of 308 stainless steel weld metal currently used as a reference. In the slurry erosion testing, the volume loss of Stellite® 6 applied by the HVOF process was 5.33 cubic mm/h, much lower than the corresponding loss (11.17 cubic mm/h) in the currently used stainless steel 304 reference. Furthermore, the electrochemical potential difference between the carbon steel and HVOF sprayed Stellite 6 coating was 0.25 volts, half the potential difference between the 304 stainless steel carbon steel substrate, and will result in reduced galvanic corrosion of the substrate near the contact areas. Stellite 6 deposited by the HVOF process was recommended for repair of damage resulting from erosion and subsequent cavitation by caused by surface roughening.

  17. The effect of aging on the DNA damage and repair capacity in 2BS cells undergoing oxidative stress.

    Science.gov (United States)

    Wang, Jin-Ling; Wang, Pei-Chang

    2012-01-01

    Aging is associated with a reduction in the DNA repair capacity under oxidative stress. However, whether the DNA damage and repair capacity can be a biomarker of aging remains controversial. In this study, we demonstrated two cause-and-effect relationships, the one is between the DNA damage and repair capacity and the cellular age, another is between DNA damage and repair capacity and the level of oxidative stress in human embryonic lung fibroblasts (2BS) exposed to different doses of hydrogen peroxide (H2O2). To clarify the mechanisms of the age-related reduction in DNA damage and repair capacity, we preliminarily evaluated the expressions of six kinds of pivotal enzymes involved in the two classical DNA repair pathways. The DNA repair capacity was observed in human fibroblasts cells using the comet assay; the age-related DNA repair enzymes were selected by RT-PCR and then verified by Western blot in vitro. Results showed that the DNA repair capacity was negatively and linearly correlated with (i) cumulative population doubling (PD) levels only in the group of low concentration of hydrogen peroxide treatment, (ii) with the level of oxidative stress only in the group of young PD cells. The mRNA expression of DNA polymerase δ1 decreased substantially in senescent cells and showed negative linear-correlation with PD levels; the protein expression level was well consistent with the mRNA level. Taken together, DNA damage and repair capacity can be a biomarker of aging. Reduced expression of DNA polymerase δ1 may be responsible for the decrease of DNA repair capacity in senescent cells.

  18. Complement activation in the context of stem cells and tissue repair

    Institute of Scientific and Technical Information of China (English)

    Ingrid; U; Schraufstatter; Sophia; K; Khaldoyanidi; Richard; G; DiScipio

    2015-01-01

    The complement pathway is best known for its role in immune surveillance and inflammation. However,its ability of opsonizing and removing not only pathogens,but also necrotic and apoptotic cells,is a phylogenetically ancient means of initiating tissue repair. The means and mechanisms of complement-mediated tissue repair are discussed in this review. There is increasing evidence that complement activation contributes to tissue repair at several levels. These range from the chemo-attraction of stem and progenitor cells to areas of complement activation,to increased survival of various cell types in the presence of split products of complement,and to the production of trophic factors by cells activated by the anaphylatoxins C3 a and C5 a. This repair aspect of complement biology has not found sufficient appreciation until recently. The following will examine this aspect of complement biology with an emphasis on the anaphylatoxins C3 a and C5 a.

  19. 49 CFR 1242.36 - Machinery repair and equipment damaged (accounts XX-26-40 and XX-26-48).

    Science.gov (United States)

    2010-10-01

    ... 49 Transportation 9 2010-10-01 2010-10-01 false Machinery repair and equipment damaged (accounts XX-26-40 and XX-26-48). 1242.36 Section 1242.36 Transportation Other Regulations Relating to... FOR RAILROADS 1 Operating Expenses-Equipment § 1242.36 Machinery repair and equipment...

  20. DNA Damage Follows Repair Factor Depletion and Portends Genome Variation in Cancer Cells after Pore Migration.

    Science.gov (United States)

    Irianto, Jerome; Xia, Yuntao; Pfeifer, Charlotte R; Athirasala, Avathamsa; Ji, Jiazheng; Alvey, Cory; Tewari, Manu; Bennett, Rachel R; Harding, Shane M; Liu, Andrea J; Greenberg, Roger A; Discher, Dennis E

    2017-01-23

    Migration through micron-size constrictions has been seen to rupture the nucleus, release nuclear-localized GFP, and cause localized accumulations of ectopic 53BP1-a DNA repair protein. Here, constricted migration of two human cancer cell types and primary mesenchymal stem cells (MSCs) increases DNA breaks throughout the nucleoplasm as assessed by endogenous damage markers and by electrophoretic "comet" measurements. Migration also causes multiple DNA repair proteins to segregate away from DNA, with cytoplasmic mis-localization sustained for many hours as is relevant to delayed repair. Partial knockdown of repair factors that also regulate chromosome copy numbers is seen to increase DNA breaks in U2OS osteosarcoma cells without affecting migration and with nucleoplasmic patterns of damage similar to constricted migration. Such depletion also causes aberrant levels of DNA. Migration-induced nuclear damage is nonetheless reversible for wild-type and sub-cloned U2OS cells, except for lasting genomic differences between stable clones as revealed by DNA arrays and sequencing. Gains and losses of hundreds of megabases in many chromosomes are typical of the changes and heterogeneity in bone cancer. Phenotypic differences that arise from constricted migration of U2OS clones are further illustrated by a clone with a highly elongated and stable MSC-like shape that depends on microtubule assembly downstream of the transcription factor GATA4. Such changes are consistent with reversion to a more stem-like state upstream of cancerous osteoblastic cells. Migration-induced genomic instability can thus associate with heritable changes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  1. Effects of granulocyte-macrophage colony stimulating factor on the repair of vessel intima damaged by balloon

    Institute of Scientific and Technical Information of China (English)

    ZHANG Xing-hua; MA Xiao-jing; ZHAO Tong

    2005-01-01

    Background The dysfunction of vascular endothelial cells plays a key role in starting and facilitating restenosis. The acceleration of intima repair and the recovery of endothelial function would reduce the restenosis rate. This study was undertaken to assess the effect of granulocyte-macrophage colony stimulating factor (GM-CSF) on the repair of damaged iliac arteries.Methods Twenty-four male New Zealand white rabbits undergoing primary iliac artery deendothelialization were randomly divided into two groups (GM-CSF group and control group). The GM-CSF group received a subcutaneous injection of GM-CSF (10 μg·kg-1·d-1), and the control group was given a subcutaneous injection of equivalent saline. The iliac arteries of all animals were damaged by balloon after 7 days. The levels of nitric oxide (NO) were detected before, 1 week, 2 weeks and 4 weeks after angioplasty. The repair and hyperplasia of the intima were observed microscopically and the indices of stenosis were evaluated by computerized planimetry after 4 weeks of angioplasty.Results The NO levels of the GM-CSF group were higher than those of the control group 2 weeks and 4 weeks after angioplasty [(91.92±11.57) μmol/L vs. (81.67±12.18) μmol/L; (97.67±10.13) μmol/L vs. (83.16±12.64) μmol/L]. Four weeks after balloon damage, histological examination showed that neointima formation, vascular smooth muscle cells and fibrous tissue of the GM-CSF group were less than those of the control group. The endothelium of the GM-CSF group was more integrated, and stenosis of lumen was slighter than that of the control group. Morphometry showed the lumen area of the GM-CSF group was larger than that of the control group [(1.27±0.31) mm2 vs. (0.92±0.24) mm2], the neointimal area and percent of intima hyperplasia were significantly smaller than those of the control group [(0.85±0.34) mm2 vs. (1.18±0.38) mm2; (40±7)% vs. (55±6)%].Conclusion GM-CSF could facilitate the repair of the intima, reduce neointima

  2. An immunochemical approach to the study of DNA damage and repair

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, S.S. (Vermont Univ., Burlington, VT (United States). Dept. of Microbiology and Molecular Genetics); Erlanger, B.F. (Columbia Univ., New York, NY (United States). Dept. of Microbiology)

    1992-05-01

    The overall objective of this project has been to develop immunochemical methods to quantitate unique DNA base damages in order to facilitate studies on radiation-induced damage production and repair. Specifically, we have been using antibodies raised to damaged bases to quantitate unique lesions in model systems in order to evaluate their potential biological consequences. Our approach has been to synthesize modified nucleotides or nucleosides, conjugate them to protein carriers, and use the conjugates as immunogens in rabbits or to prepare monoclonal antibodies. We have been studying damages that are stable radiolysis products found in X-irradiated DNA and thus of potential biological consequence. Our aim is to build an in vitro and in vivo data base on the interactions between model DNA lesions and such cellular enzymes as DNA polymerases and repair endonucleases. Initial studies have focused on pyrimidine ring saturation products (thymine glycol.and dihydrothymine), products resulting from ring fragmentation or base loss (urea, {Beta}-ureidoisobutyric acid, abasic sites), 7-hydro-8-oxopurines, and more recently, cytosine radiolysis products. These modified bases serve as useful models for examining the potential lethal and/or mutagenic (carcinogenic) effects of the products of DNA radiolysis.

  3. The role of DNA damage and repair in decitabine-mediated apoptosis in multiple myeloma.

    Science.gov (United States)

    Maes, Ken; De Smedt, Eva; Lemaire, Miguel; De Raeve, Hendrik; Menu, Eline; Van Valckenborgh, Els; McClue, Steve; Vanderkerken, Karin; De Bruyne, Elke

    2014-05-30

    DNA methyltransferase inhibitors (DNMTi) and histone deacetylase inhibitors (HDACi) are under investigation for the treatment of cancer, including the plasma cell malignancy multiple myeloma (MM). Evidence exists that DNA damage and repair contribute to the cytotoxicity mediated by the DNMTi decitabine. Here, we investigated the DNA damage response (DDR) induced by decitabine in MM using 4 human MM cell lines and the murine 5T33MM model. In addition, we explored how the HDACi JNJ-26481585 affects this DDR. Decitabine induced DNA damage (gamma-H2AX foci formation), followed by a G0/G1- or G2/M-phase arrest and caspase-mediated apoptosis. JNJ-26481585 enhanced the anti-MM effect of decitabine both in vitro and in vivo. As JNJ-26481585 did not enhance decitabine-mediated gamma-H2AX foci formation, we investigated the DNA repair response towards decitabine and/or JNJ-26481585. Decitabine augmented RAD51 foci formation (marker for homologous recombination (HR)) and/or 53BP1 foci formation (marker for non-homologous end joining (NHEJ)). Interestingly, JNJ-26481585 negatively affected basal or decitabine-induced RAD51 foci formation. Finally, B02 (RAD51 inhibitor) enhanced decitabine-mediated apoptosis. Together, we report that decitabine-induced DNA damage stimulates HR and/or NHEJ. JNJ-26481585 negatively affects RAD51 foci formation, thereby providing an additional explanation for the combinatory effect between decitabine and JNJ-26481585.

  4. DNA damage precedes apoptosis during the regression of the interdigital tissue in vertebrate embryos

    Science.gov (United States)

    Montero, Juan A.; Sanchez-Fernandez, Cristina; Lorda-Diez, Carlos I.; Garcia-Porrero, Juan A.; Hurle, Juan M.

    2016-01-01

    DNA damage independent of caspase activation accompanies programmed cell death in different vertebrate embryonic organs. We analyzed the significance of DNA damage during the regression of the interdigital tissue, which sculpts the digits in the embryonic limb. Interdigit remodeling involves oxidative stress, massive apoptosis and cell senescence. Phosphorylation of H2AX mediated by ATM precedes caspase dependent apoptosis and cell senescence during interdigit regression. The association of γH2AX with other downstream DNA repair factors, including MDC1, Rad50 and 53BP1 suggests a defensive response of cells against DNA damage. The relative distribution of cells γH2AX-only positive, TUNEL-only positive, and cells double positive for both markers is consistent with a sequence of degenerative events starting by damage of the DNA. In support of this interpretation, the relative number of γH2AX-only cells increases after caspase inhibition while the relative number of TUNEL-only cells increases after inhibition of ATM. Furthermore, cultured interdigits survived and maintained intense chondrogenic potential, even at advanced stages of degeneration, discarding a previous commitment to die. Our findings support a new biological paradigm considering embryonic cell death secondary to genotoxic stimuli, challenging the idea that considers physiological cell death a cell suicide regulated by an internal death clock that pre-programmes degeneration. PMID:27752097

  5. Autologous tissue repair of large abdominal wall defects.

    NARCIS (Netherlands)

    Vries Reilingh, T.S. de; Bodegom, M.E.; Goor, H. van; Hartman, E.H.M.; Wilt, G.J. van der; Bleichrodt, R.P.

    2007-01-01

    BACKGROUND AND METHOD: Techniques for autologous repair of abdominal wall defects that could not be closed primarily are reviewed. Medline and PubMed were searched for English or German publications using the following keywords: components separation technique (CST), Ramirez, da Silva, fascia lata,

  6. Actualities on molecular pathogenesis and repairing processes of cerebral damage in perinatal hypoxic-ischemic encephalopathy.

    Science.gov (United States)

    Distefano, Giuseppe; Praticò, Andrea D

    2010-09-16

    Hypoxic-ischemic encephalopathy (HIE) is the most important cause of cerebral damage and long-term neurological sequelae in the perinatal period both in term and preterm infant. Hypoxic-ischemic (H-I) injuries develop in two phases: the ischemic phase, dominated by necrotic processes, and the reperfusion phase, dominated by apoptotic processes extending beyond ischemic areas. Due to selective ischemic vulnerability, cerebral damage affects gray matter in term newborns and white matter in preterm newborns with the typical neuropathological aspects of laminar cortical necrosis in the former and periventricular leukomalacia in the latter. This article summarises the principal physiopathological and biochemical processes leading to necrosis and/or apoptosis of neuronal and glial cells and reports recent insights into some endogenous and exogenous cellular and molecular mechanisms aimed at repairing H-I cerebral damage.

  7. Actualities on molecular pathogenesis and repairing processes of cerebral damage in perinatal hypoxic-ischemic encephalopathy

    Directory of Open Access Journals (Sweden)

    Praticò Andrea D

    2010-09-01

    Full Text Available Abstract Hypoxic-ischemic encephalopathy (HIE is the most important cause of cerebral damage and long-term neurological sequelae in the perinatal period both in term and preterm infant. Hypoxic-ischemic (H-I injuries develop in two phases: the ischemic phase, dominated by necrotic processes, and the reperfusion phase, dominated by apoptotic processes extending beyond ischemic areas. Due to selective ischemic vulnerability, cerebral damage affects gray matter in term newborns and white matter in preterm newborns with the typical neuropathological aspects of laminar cortical necrosis in the former and periventricular leukomalacia in the latter. This article summarises the principal physiopathological and biochemical processes leading to necrosis and/or apoptosis of neuronal and glial cells and reports recent insights into some endogenous and exogenous cellular and molecular mechanisms aimed at repairing H-I cerebral damage.

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

    Science.gov (United States)

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

    2013-09-17

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

  9. Joint homeostasis in tissue engineering for cartilage repair

    NARCIS (Netherlands)

    Saris, D.B.F.

    2002-01-01

    Traumatic joint damage, articular cartilage and the research into methods of restoring the articulation are not new topics of interest. For centuries, clinicians have recognized the importance of cartilage damage and sought ways of learning about the normal form and function of hyaline cartilage as

  10. Dietary phytochemicals, HDAC inhibition, and DNA damage/repair defects in cancer cells

    Directory of Open Access Journals (Sweden)

    Rajendran Praveen

    2011-10-01

    Full Text Available Abstract Genomic instability is a common feature of cancer etiology. This provides an avenue for therapeutic intervention, since cancer cells are more susceptible than normal cells to DNA damaging agents. However, there is growing evidence that the epigenetic mechanisms that impact DNA methylation and histone status also contribute to genomic instability. The DNA damage response, for example, is modulated by the acetylation status of histone and non-histone proteins, and by the opposing activities of histone acetyltransferase and histone deacetylase (HDAC enzymes. Many HDACs overexpressed in cancer cells have been implicated in protecting such cells from genotoxic insults. Thus, HDAC inhibitors, in addition to unsilencing tumor suppressor genes, also can silence DNA repair pathways, inactivate non-histone proteins that are required for DNA stability, and induce reactive oxygen species and DNA double-strand breaks. This review summarizes how dietary phytochemicals that affect the epigenome also can trigger DNA damage and repair mechanisms. Where such data is available, examples are cited from studies in vitro and in vivo of polyphenols, organosulfur/organoselenium compounds, indoles, sesquiterpene lactones, and miscellaneous agents such as anacardic acid. Finally, by virtue of their genetic and epigenetic mechanisms, cancer chemopreventive agents are being redefined as chemo- or radio-sensitizers. A sustained DNA damage response coupled with insufficient repair may be a pivotal mechanism for apoptosis induction in cancer cells exposed to dietary phytochemicals. Future research, including appropriate clinical investigation, should clarify these emerging concepts in the context of both genetic and epigenetic mechanisms dysregulated in cancer, and the pros and cons of specific dietary intervention strategies.

  11. Anhydrobiosis-associated nuclear DNA damage and repair in the sleeping chironomid: linkage with radioresistance.

    Directory of Open Access Journals (Sweden)

    Oleg Gusev

    Full Text Available Anhydrobiotic chironomid larvae can withstand prolonged complete desiccation as well as other external stresses including ionizing radiation. To understand the cross-tolerance mechanism, we have analyzed the structural changes in the nuclear DNA using transmission electron microscopy and DNA comet assays in relation to anhydrobiosis and radiation. We found that dehydration causes alterations in chromatin structure and a severe fragmentation of nuclear DNA in the cells of the larvae despite successful anhydrobiosis. Furthermore, while the larvae had restored physiological activity within an hour following rehydration, nuclear DNA restoration typically took 72 to 96 h. The DNA fragmentation level and the recovery of DNA integrity in the rehydrated larvae after anhydrobiosis were similar to those of hydrated larvae irradiated with 70 Gy of high-linear energy transfer (LET ions ((4He. In contrast, low-LET radiation (gamma-rays of the same dose caused less initial damage to the larvae, and DNA was completely repaired within within 24 h. The expression of genes encoding the DNA repair enzymes occurred upon entering anhydrobiosis and exposure to high- and low-LET radiations, indicative of DNA damage that includes double-strand breaks and their subsequent repair. The expression of antioxidant enzymes-coding genes was also elevated in the anhydrobiotic and the gamma-ray-irradiated larvae that probably functions to reduce the negative effect of reactive oxygen species upon exposure to these stresses. Indeed the mature antioxidant proteins accumulated in the dry larvae and the total activity of antioxidants increased by a 3-4 fold in association with anhydrobiosis. We conclude that one of the factors explaining the relationship between radioresistance and the ability to undergo anhydrobiosis in the sleeping chironomid could be an adaptation to desiccation-inflicted nuclear DNA damage. There were also similarities in the molecular response of the larvae to

  12. Transcriptional profiling differences for articular cartilage and repair tissue in equine joint surface lesions

    Directory of Open Access Journals (Sweden)

    Stromberg Arnold J

    2009-09-01

    Full Text Available Abstract Background Full-thickness articular cartilage lesions that reach to the subchondral bone yet are restricted to the chondral compartment usually fill with a fibrocartilage-like repair tissue which is structurally and biomechanically compromised relative to normal articular cartilage. The objective of this study was to evaluate transcriptional differences between chondrocytes of normal articular cartilage and repair tissue cells four months post-microfracture. Methods Bilateral one-cm2 full-thickness defects were made in the articular surface of both distal femurs of four adult horses followed by subchondral microfracture. Four months postoperatively, repair tissue from the lesion site and grossly normal articular cartilage from within the same femorotibial joint were collected. Total RNA was isolated from the tissue samples, linearly amplified, and applied to a 9,413-probe set equine-specific cDNA microarray. Eight paired comparisons matched by limb and horse were made with a dye-swap experimental design with validation by histological analyses and quantitative real-time polymerase chain reaction (RT-qPCR. Results Statistical analyses revealed 3,327 (35.3% differentially expressed probe sets. Expression of biomarkers typically associated with normal articular cartilage and fibrocartilage repair tissue corroborate earlier studies. Other changes in gene expression previously unassociated with cartilage repair were also revealed and validated by RT-qPCR. Conclusion The magnitude of divergence in transcriptional profiles between normal chondrocytes and the cells that populate repair tissue reveal substantial functional differences between these two cell populations. At the four-month postoperative time point, the relative deficiency within repair tissue of gene transcripts which typically define articular cartilage indicate that while cells occupying the lesion might be of mesenchymal origin, they have not recapitulated differentiation to

  13. Assessing laser-tissue damage with bioluminescent imaging

    Science.gov (United States)

    Wilmink, Gerald J.; Opalenik, Susan R.; Beckham, Josh T.; Davidson, Jeffrey M.; Jansen, Eric D.

    2006-07-01

    Effective medical laser procedures are achieved by selecting laser parameters that minimize undesirable tissue damage. Traditionally, human subjects, animal models, and monolayer cell cultures have been used to study wound healing, tissue damage, and cellular effects of laser radiation. Each of these models has significant limitations, and consequently, a novel skin model is needed. To this end, a highly reproducible human skin model that enables noninvasive and longitudinal studies of gene expression was sought. In this study, we present an organotypic raft model (engineered skin) used in combination with bioluminescent imaging (BLI) techniques. The efficacy of the raft model was validated and characterized by investigating the role of heat shock protein 70 (hsp70) as a sensitive marker of thermal damage. The raft model consists of human cells incorporated into an extracellular matrix. The raft cultures were transfected with an adenovirus containing a murine hsp70 promoter driving transcription of luciferase. The model enables quantitative analysis of spatiotemporal expression of proteins using BLI. Thermal stress was induced on the raft cultures by means of a constant temperature water bath or with a carbon dioxide (CO2) laser (λ=10.6 µm, 0.679 to 2.262 W/cm2, cw, unfocused Gaussian beam, ωL=4.5 mm, 1 min exposure). The bioluminescence was monitored noninvasively with an IVIS 100 Bioluminescent Imaging System. BLI indicated that peak hsp70 expression occurs 4 to 12 h after exposure to thermal stress. A minimum irradiance of 0.679 W/cm2 activated the hsp70 response, and a higher irradiance of 2.262 W/cm2 was associated with a severe reduction in hsp70 response due to tissue ablation. Reverse transcription polymerase chain reaction demonstrated that hsp70 mRNA levels increased with prolonged heating exposures. Enzyme-linked immunosorbent protein assays confirmed that luciferase was an accurate surrogate for hsp70 intracellular protein levels. Hematoxylin and

  14. Assessing laser-tissue damage with bioluminescent imaging.

    Science.gov (United States)

    Wilmink, Gerald J; Opalenik, Susan R; Beckham, Joshua T; Davidson, Jeffrey M; Jansen, E Duco

    2006-01-01

    Effective medical laser procedures are achieved by selecting laser parameters that minimize undesirable tissue damage. Traditionally, human subjects, animal models, and monolayer cell cultures have been used to study wound healing, tissue damage, and cellular effects of laser radiation. Each of these models has significant limitations, and consequently, a novel skin model is needed. To this end, a highly reproducible human skin model that enables noninvasive and longitudinal studies of gene expression was sought. In this study, we present an organotypic raft model (engineered skin) used in combination with bioluminescent imaging (BLI) techniques. The efficacy of the raft model was validated and characterized by investigating the role of heat shock protein 70 (hsp70) as a sensitive marker of thermal damage. The raft model consists of human cells incorporated into an extracellular matrix. The raft cultures were transfected with an adenovirus containing a murine hsp70 promoter driving transcription of luciferase. The model enables quantitative analysis of spatiotemporal expression of proteins using BLI. Thermal stress was induced on the raft cultures by means of a constant temperature water bath or with a carbon dioxide (CO2) laser (lambda=10.6 microm, 0.679 to 2.262 Wcm2, cw, unfocused Gaussian beam, omegaL=4.5 mm, 1 min exposure). The bioluminescence was monitored noninvasively with an IVIS 100 Bioluminescent Imaging System. BLI indicated that peak hsp70 expression occurs 4 to 12 h after exposure to thermal stress. A minimum irradiance of 0.679 Wcm2 activated the hsp70 response, and a higher irradiance of 2.262 Wcm2 was associated with a severe reduction in hsp70 response due to tissue ablation. Reverse transcription polymerase chain reaction demonstrated that hsp70 mRNA levels increased with prolonged heating exposures. Enzyme-linked immunosorbent protein assays confirmed that luciferase was an accurate surrogate for hsp70 intracellular protein levels. Hematoxylin

  15. 游离股前外侧皮瓣修复四肢皮肤软组织缺损12例临床疗效分析%Analysis of Clinical Curative Effect of the Free Anteriolateral Skin Flap of Thigh Repair Soft Tissue Damage of Limbs 12 Cases

    Institute of Scientific and Technical Information of China (English)

    孔靖

    2013-01-01

      目的:探讨游离股前外侧皮瓣修复四肢皮肤软组织缺损的临床疗效。方法:2008年1月~2012年6月,采用吻合血管的游离股前外侧皮瓣修复四肢皮肤软组织缺损12例,皮瓣切取面积8cm×12cm~24cm×14cm。结果:12例皮瓣均成活,术后随访3~18个月,所有患者创面愈合良好,功能恢复满意。结论:游离股前外侧皮瓣存活率高,血运丰富,部位隐蔽,是修复四肢皮肤软组织缺损的理想皮瓣。%Objective:To explore the result of repairing the limbs soft tissue defect of removing anterolateral skin flap of thigh. Methods:From January 2008 to June 2012, the vascular anastomosis of free shares anterolateral skin flap to repair defects of soft tissue limbs in 12 cases, flap chipped area 8 cm × 12 cm~24 cm × 14 cm. Results:12 cases are the flap survival and were followed up for 3 to 18 months, all patients wound healing is good, the function recovered satisfactorily. Conclusion:The survival rate of free anterolateral skin flap is high, the supply of rich blood, location concealed, the free anterolateral skin flap is an ideal flap for repairing defects of soft tissure.

  16. Effect of caffeine and adenosine on G2 repair: mitotic delay and chromosome damage.

    Science.gov (United States)

    González-Fernández, A; Hernández, P; López-Sáez, J F

    1985-04-01

    Proliferating plant cells treated during the late S period with 5-aminouracil (AU), give the typical response that DNA-damaging agents induce, characterized by: an important mitotic delay, and a potentiation of the chromosome damage by caffeine post-treatment. The study of labelled prophases, after a tritiated thymidine pulse, allowed evaluation of the mitotic delay induced by AU as well as its reversion by caffeine, while chromosome damage was estimated by the percentage of anaphases and telophases showing chromosomal aberrations. Post-treatment with adenosine alone has shown no effect on mitotic delay or chromosomal damage. However, when cells after AU were incubated in caffeine plus adenosine, the chromosome damage potentiation was abolished without affecting the caffeine action on mitotic delay. As a consequence, we postulate that caffeine could have two effects on G2 cells with damaged DNA: the first, to cancel their mitotic delay and the second to inhibit some DNA-repair pathway(s). Only this last effect could be reversed by adenosine.

  17. Investigation of the effect of PHA-matrices with different protein coating on the speed of recovery of damaged skin tissue of rats

    Directory of Open Access Journals (Sweden)

    Yana Yacenko

    2015-05-01

    Full Text Available The problem of creating innovative biopolymer scaffolds used in reconstructive medicine to repair damaged skin. A description of the results of the experiment on the use of polyhydroxyalkanoate-matrix with the protein coating on the simulated skin tissue defects in rats.

  18. Investigation of the effect of PHA-matrices with different protein coating on the speed of recovery of damaged skin tissue of rats

    OpenAIRE

    Yana Yacenko; Elena Nikolaeva

    2015-01-01

    The problem of creating innovative biopolymer scaffolds used in reconstructive medicine to repair damaged skin. A description of the results of the experiment on the use of polyhydroxyalkanoate-matrix with the protein coating on the simulated skin tissue defects in rats.

  19. Development of biodegradable hyper-branched tissue adhesives for the repair of meniscus tears

    NARCIS (Netherlands)

    Bochynska, A. I.; Van Tienen, T. G.; Hannink, G.; Buma, P.; Grijpma, D. W.

    2016-01-01

    Meniscus tears are one of the most commonly occurring injuries of the knee joint. Current meniscus repair techniques are challenging and do not bring fully satisfactory results. Tissue adhesives are a promising alternative, since they are easy to apply and cause minimal tissue trauma. In this study,

  20. Space Radiation Effects on Human Cells: Modeling DNA Breakage, DNA Damage Foci Distribution, Chromosomal Aberrations and Tissue Effects

    Science.gov (United States)

    Ponomarev, A. L.; Huff, J. L.; Cucinotta, F. A.

    2011-01-01

    Future long-tem space travel will face challenges from radiation concerns as the space environment poses health risk to humans in space from radiations with high biological efficiency and adverse post-flight long-term effects. Solar particles events may dramatically affect the crew performance, while Galactic Cosmic Rays will induce a chronic exposure to high-linear-energy-transfer (LET) particles. These types of radiation, not present on the ground level, can increase the probability of a fatal cancer later in astronaut life. No feasible shielding is possible from radiation in space, especially for the heavy ion component, as suggested solutions will require a dramatic increase in the mass of the mission. Our research group focuses on fundamental research and strategic analysis leading to better shielding design and to better understanding of the biological mechanisms of radiation damage. We present our recent effort to model DNA damage and tissue damage using computational models based on the physics of heavy ion radiation, DNA structure and DNA damage and repair in human cells. Our particular area of expertise include the clustered DNA damage from high-LET radiation, the visualization of DSBs (DNA double strand breaks) via DNA damage foci, image analysis and the statistics of the foci for different experimental situations, chromosomal aberration formation through DSB misrepair, the kinetics of DSB repair leading to a model-derived spectrum of chromosomal aberrations, and, finally, the simulation of human tissue and the pattern of apoptotic cell damage. This compendium of theoretical and experimental data sheds light on the complex nature of radiation interacting with human DNA, cells and tissues, which can lead to mutagenesis and carcinogenesis later in human life after the space mission.

  1. Zicam-induced damage to mouse and human nasal tissue.

    Directory of Open Access Journals (Sweden)

    Jae H Lim

    Full Text Available Intranasal medications are used to treat various nasal disorders. However, their effects on olfaction remain unknown. Zicam (zinc gluconate; Matrixx Initiatives, Inc, a homeopathic substance marketed to alleviate cold symptoms, has been implicated in olfactory dysfunction. Here, we investigated Zicam and several common intranasal agents for their effects on olfactory function. Zicam was the only substance that showed significant cytotoxicity in both mouse and human nasal tissue. Specifically, Zicam-treated mice had disrupted sensitivity of olfactory sensory neurons to odorant stimulation and were unable to detect novel odorants in behavioral testing. These findings were long-term as no recovery of function was observed after two months. Finally, human nasal explants treated with Zicam displayed significantly elevated extracellular lactate dehydrogenase levels compared to saline-treated controls, suggesting severe necrosis that was confirmed on histology. Our results demonstrate that Zicam use could irreversibly damage mouse and human nasal tissue and may lead to significant smell dysfunction.

  2. Repair work begins on the external tank of Space Shuttle Discovery after damage from hail

    Science.gov (United States)

    1999-01-01

    United Space Alliance technician Don Pataky repairs one of the hail-created divots in the foam insulation on the external tank of Space Shuttle Discovery. The Shuttle was rolled back from Pad 39B to the Vehicle Assemby Building for repairs because access to all of the damaged areas was not possible at the pad. The work is expected to take two to three days, allowing Discovery to roll back to the pad late this week for launch of mission STS-96, the 94th launch in the Space Shuttle Program. Liftoff will occur no earlier than May 27. STS-96 is a logistics and resupply mission for the International Space Station, carrying such payloads as a Russian crane, the Strela; a U.S.-built crane; the Spacehab Oceaneering Space System Box (SHOSS), a logistics items carrier; and STARSHINE, a student-shared experiment.

  3. Repair work begins on the external tank of Space Shuttle Discovery after damage from hail

    Science.gov (United States)

    1999-01-01

    Standing inside a protective tent around the external tank of Space Shuttle Discovery in the Vehicle Assembly Building (VAB), United Space Alliance technician Don Pataky repairs divots caused by hail storms. The Shuttle was rolled back from Pad 39B to the VAB for repairs because access to all of the damaged areas was not possible at the pad. The work is expected to take two to three days, allowing Discovery to roll back to the pad late this week for launch of mission STS-96, the 94th launch in the Space Shuttle Program. Liftoff will occur no earlier than May 27. STS- 96 is a logistics and resupply mission for the International Space Station, carrying such payloads as a Russian crane, the Strela; a U.S.-built crane; the Spacehab Oceaneering Space System Box (SHOSS), a logistics items carrier; and STARSHINE, a student- shared experiment.

  4. Space Transportation System (STS)-117 External Tank (ET)-124 Hail Damage Repair Assessment

    Science.gov (United States)

    Wilson, Timmy R.; Gentz, Steven J.; Barth, Timothy S.; Minute, Stephen A.; Flowers, Cody P.; Hamilton, David A.; Null, Cynthia H.; Schafer, Charles F.

    2009-01-01

    Severe thunderstorms with associated hail and high winds struck the STS-117 stack on February 26, 2007. Peak winds were recorded at 62 knots with hail sizes ranging from 0.3 inch to 0.8 inch in diameter. As a result of the storm, the North Carolina Foam Institute (NCFI) type 24-124 Thermal Protection System (TPS) foam on the liquid oxygen (LO2) ogive acreage incurred significant impact damage. The NCFI on the ET intertank and the liquid hydrogen (LH2) acreage sustained hail damage. The Polymer Development Laboratory (PDL)-1034 foam of the LO2 ice frost ramps (IFRs) and the Super-Lightweight Ablator (SLA) of the LO2 cable tray also suffered minor damage. NASA Engineering and Safety Center (NESC) was asked to assess the technical feasibility of repairing the ET TPS, the reasonableness of conducting those repairs with the vehicle in a vertical, integrated configuration at the Kennedy Space Center (KSC) Vehicle Assemble Building (VAB), and to address attendant human factors considerations including worker fatigue and the potential for error. The outcome of the assessment is recorded in this document.

  5. Effect of the repaired damage morphology of fused silica on the modulation of incident laser

    Science.gov (United States)

    Gao, X.; Jiang, Y.; Qiu, R.; Zhou, Q.; Zuo, R.; Zhou, G. R.; Yao, K.

    2017-02-01

    Local CO2 laser treatment has proved to be the most promising method to extend the life-time of fused silica. However, previous experimental data show that some raised rims are observed around the mitigated sites left from the mitigation process, which will result in hazardous light modulation to the downstream optics. In this work, the morphology features of mitigated sites on the surface of fused silica optics were analyzed in detail. According to measured morphology features, a 3D analytical model for simulating the modulation value induced by mitigated site has been developed based on the scalar diffraction theory. The diffraction patterns at a discrete distance downstream from each mitigated site are measured. The influences of geometry, laser wavelength and refractive index of substrates on the modulation by repaired damage morphology at different distances are discussed, respectively. The analytical model is usable and representative to evaluate the hazardous modulation induced by repaired damage morphology to downstream optics. Results on this research suggest that the downstream intensification can be suppressed by controlling the morphology features of mitigated sites, which provides a direction for the development and improvement of the mitigated techniques of damage optics.

  6. Assessment of okadaic acid effects on cytotoxicity, DNA damage and DNA repair in human cells.

    Science.gov (United States)

    Valdiglesias, Vanessa; Méndez, Josefina; Pásaro, Eduardo; Cemeli, Eduardo; Anderson, Diana; Laffon, Blanca

    2010-07-07

    Okadaic acid (OA) is a phycotoxin produced by several types of dinoflagellates causing diarrheic shellfish poisoning (DSP) in humans. Symptoms induced by DSP toxins are mainly gastrointestinal, but the intoxication does not appear to be fatal. Despite this, this toxin presents a potential threat to human health even at concentrations too low to induce acute toxicity, since previous animal studies have shown that OA has very potent tumour promoting activity. However, its concrete action mechanism has not been described yet and the results reported with regard to OA cytotoxicity and genotoxicity are often contradictory. In the present study, the genotoxic and cytotoxic effects of OA on three different types of human cells (peripheral blood leukocytes, HepG2 hepatoma cells, and SHSY5Y neuroblastoma cells) were evaluated. Cells were treated with a range of OA concentrations in the presence and absence of S9 fraction, and MTT test and Comet assay were performed in order to evaluate cytotoxicity and genotoxicity, respectively. The possible effects of OA on DNA repair were also studied by means of the DNA repair competence assay, using bleomycin as DNA damage inductor. Treatment with OA in absence of S9 fraction induced not statistically significant decrease in cell viability and significant increase in DNA damage in all cell types at the highest concentrations investigated. However, only SHSY5Y cells showed OA induced genotoxic and cytotoxic effects in presence of S9 fraction. Furthermore, we found that OA can induce modulations in DNA repair processes when exposure was performed prior to BLM treatment, in co-exposure, or during the subsequent DNA repair process. Copyright 2010 Elsevier B.V. All rights reserved.

  7. Nrf2 facilitates repair of radiation induced DNA damage through homologous recombination repair pathway in a ROS independent manner in cancer cells

    Energy Technology Data Exchange (ETDEWEB)

    Jayakumar, Sundarraj; Pal, Debojyoti; Sandur, Santosh K., E-mail: sskumar@barc.gov.in

    2015-09-15

    Highlights: • Nrf2 inhibition in A549 cells led to attenuated DNA repair and radiosensitization. • Influence of Nrf2 on DNA repair is not linked to its antioxidant function. • Nrf2 influences DNA repair through homologous recombination (HR) repair pathway. • Many genes involved in HR pathway show ARE sequences in their upstream region. - Abstract: Nrf2 is a redox sensitive transcription factor that is involved in the co-ordinated transcription of genes involved in redox homeostasis. But the role of Nrf2 in DNA repair is not investigated in detail. We have employed A549 and MCF7 cells to study the role of Nrf2 on DNA repair by inhibiting Nrf2 using all-trans retinoic acid (ATRA) or by knock down approach prior to radiation exposure (4 Gy). DNA damage and repair analysis was studied by γH2AX foci formation and comet assay. Results suggested that the inhibition of Nrf2 in A549 or MCF7 cells led to significant slowdown in DNA repair as compared to respective radiation controls. The persistence of residual DNA damage even in the presence of free radical scavenger N-acetyl cysteine, suggested that the influence of Nrf2 on DNA repair was not linked to its antioxidant functions. Further, its influence on non-homologous end joining repair pathway was studied by inhibiting both Nrf2 and DNA-PK together. This led to synergistic reduction of survival fraction, indicating that Nrf2 may not be influencing the NHEJ pathway. To investigate the role of homologous recombination repair (HR) pathway, RAD51 foci formation was monitored. There was a significant reduction in the foci formation in cells treated with ATRA or shRNA against Nrf2 as compared to their respective radiation controls. Further, Nrf2 inhibition led to significant reduction in mRNA levels of RAD51. BLAST analysis was also performed on upstream regions of DNA repair genes to identify antioxidant response element and found that many repair genes that are involved in HR pathway may be regulated by Nrf2

  8. Repair of damaged connectors of tunneled cuffed catheters with a two-piece adaptor for peritoneal dialysis.

    Science.gov (United States)

    Letachowicz, Krzysztof; Letachowicz, Waldemar; Weyde, Waclaw; Gołębiowski, Tomasz; Kusztal, Mariusz; Wątorek, Ewa; Klinger, Marian

    2012-01-01

    Although catheter use exposes the patient to several complications, tunneled cuffed catheters are widely applied for temporary or long-term vascular access. The aim of the study was to establish the rate of tunneled dialysis catheter damage and report our experience with breakage repair. All 363 cuffed tunneled hemodialysis catheters inserted into 309 patients from May 2000 to December 2008 were followed up. When connector damage was encountered, repair with a two-piece adaptor for peritoneal dialysis was attempted. Mechanical breakage occurred in 33 (9.1%) of catheters with an incidence of 0.36/1000 catheter-days. The most frequent was connector damage, found in 25 cases (67.6%). Catheter repair using a peritoneal dialysis Luer adaptor was performed with good early and long-term outcome. Tunneled catheter breakage is a relatively rare complication. Catheter repair using the adaptor for peritoneal dialysis is easy to perform, safe, and cost-effective.

  9. Delivery of human mesenchymal adipose-derived stem cells restores multiple urological dysfunctions in a rat model mimicking radical prostatectomy damages through tissue-specific paracrine mechanisms

    DEFF Research Database (Denmark)

    Yiou, René; Mahrouf-Yorgov, Meriem; Trébeau, Céline;

    2016-01-01

    Urinary incontinence (UI) and erectile dysfunction (ED) are the most common functional urological disorders and the main sequels of radical prostatectomy (RP) for prostate cancer. Mesenchymal stem cell (MSC) therapy holds promise for repairing tissue damage due to RP. Because animal studies...... accurately replicating post-RP clinical UI and ED are lacking, little is known about the mechanisms underlying the urological benefits of MSC in this setting. To determine whether and by which mechanisms MSC can repair damages to both striated urethral sphincter (SUS) and penis in the same animal, we...

  10. Solid protein solder-doped biodegradable polymer membranes for laser-assisted tissue repair

    Science.gov (United States)

    Hodges, Diane E.; McNally-Heintzelman, Karen M.; Welch, Ashley J.

    2000-05-01

    Solid protein solder-doped polymer membranes have been developed for laser-assisted tissue repair. Biodegradable polymer films of controlled porosity were fabricated with poly(L-lactic-co-glycolic acid) (PLGA) and poly(ethylene glycol) (PEG) using a solvent-casting and particulate-leaching technique. The films provided a porous scaffold that readily absorbed the traditional protein solder mix composed of bovine serum albumin (BSA) and indocyanine green (ICG) dye. In vitro investigations were conducted to assess the influence of various processing parameters on the strength of tissue repairs formed using the new membranes. These parameters included the PLGA copolymer and PLGA/PEG blend ratio, the salt particle size, the initial bovine serum albumin (BSA) weight fraction, and the laser irradiance used to denature the solder. Altering the PLGA copolymer ratio had little effect on repair strength, however, it influenced the membrane degradation rate. Repair strength increased with increased membrane pore size and BSA concentration. The addition of PEG during the film casting stage increased the flexibility of the membranes but not necessarily the repair strength. The repair strength increased with increasing irradiance from 12 W/cm2 to 15 W/cm2. The new solder-doped polymer membranes provide all of the benefits associated with solid protein solders including high repair strength and improved edge coaptation. In addition, the flexible and moldable nature of the new membranes offer the capability of tailoring the membranes to a wide range of tissue geometries, and consequently, improved clinical applicability of laser- assisted tissue repair.

  11. DNA repair efficiency in germ cells and early mouse embryos and consequences for radiation-induced transgenerational genomic damage

    Energy Technology Data Exchange (ETDEWEB)

    Marchetti, Francesco; Wyrobek, Andrew J.

    2009-01-18

    Exposure to ionizing radiation and other environmental agents can affect the genomic integrity of germ cells and induce adverse health effects in the progeny. Efficient DNA repair during gametogenesis and the early embryonic cycles after fertilization is critical for preventing transmission of DNA damage to the progeny and relies on maternal factors stored in the egg before fertilization. The ability of the maternal repair machinery to repair DNA damage in both parental genomes in the fertilizing egg is especially crucial for the fertilizing male genome that has not experienced a DNA repair-competent cellular environment for several weeks prior to fertilization. During the DNA repair-deficient period of spermatogenesis, DNA lesions may accumulate in sperm and be carried into the egg where, if not properly repaired, could result in the formation of heritable chromosomal aberrations or mutations and associated birth defects. Studies with female mice deficient in specific DNA repair genes have shown that: (i) cell cycle checkpoints are activated in the fertilized egg by DNA damage carried by the sperm; and (ii) the maternal genotype plays a major role in determining the efficiency of repairing genomic lesions in the fertilizing sperm and directly affect the risk for abnormal reproductive outcomes. There is also growing evidence that implicates DNA damage carried by the fertilizing gamete as a mediator of postfertilization processes that contribute to genomic instability in subsequent generations. Transgenerational genomic instability most likely involves epigenetic mechanisms or error-prone DNA repair processes in the early embryo. Maternal and embryonic DNA repair processes during the early phases of mammalian embryonic development can have far reaching consequences for the genomic integrity and health of subsequent generations.

  12. Quantitative assessment of optical properties in healthy cartilage and repair tissue by optical coherence tomography and histology (Conference Presentation)

    Science.gov (United States)

    Jansen, Sanne M. A.; Cernohorsky, Paul; de Bruin, Daniel M.; van der Pol, Edwin; Savci-Heijink, Cemile D.; Strackee, Simon D.; Faber, Dirk J.; van Leeuwen, Ton G.

    2016-02-01

    Quantification of the OCT signal is an important step toward clinical implementation of a diagnostic tool in cartilage imaging. Discrimination of structural cartilage differences in patients with osteoarthritis is critical, yet challenging. This study assesses the variation in the optical attenuation coefficient (μOCT) between healthy cartilage, repair tissue, bone and layers within repair tissue in a controlled setting. OCT and histology was used to assess goat talus articular surfaces in which central osteochondral defects were created. Exact matches of OCT and histology were selected for research. μOCT measurements were taken from healthy cartilage, repair tissue and bone. Measured μOCT in healthy cartilage was higher compared to both repair tissue and bone tissue. Two possible mechanisms for the difference in attenuation were investigated. We studied morphological parameters in terms of nucleus count, nucleus size and inter-nucleus distance. Collagen content in healthy cartilage and repair tissue was assessed using polarization microscopy. Quantitative analysis of the nuclei did not demonstrate a difference in nucleus size and count between healthy cartilage and repair tissue. In healthy cartilage, cells were spaced farther apart and had a lower variation in local nuclear density compared to repair tissue. Polarization microscopy suggested higher collagen content in healthy cartilage compared to repair tissue. μOCT measurements can distinguish between healthy cartilage, repair tissue and bone. Results suggest that cartilage OCT attenuation measurements could be of great impact in clinical diagnostics of osteoarthritis.

  13. Tissue Engineering for Rotator Cuff Repair: An Evidence-Based Systematic Review

    Directory of Open Access Journals (Sweden)

    Nicola Maffulli

    2012-01-01

    Full Text Available The purpose of this systematic review was to address the treatment of rotator cuff tears by applying tissue engineering approaches to improve tendon healing, specifically platelet rich plasma (PRP augmentation, stem cells, and scaffolds. Our systematic search was performed using the combination of the following terms: “rotator cuff”, “shoulder”, “PRP”, “platelet rich plasma”, “stemcells”, “scaffold”, “growth factors”, and “tissue engineering”. No level I or II studies were found on the use of scaffolds and stem cells for rotator cuff repair. Three studies compared rotator cuff repair with or without PRP augmentation. All authors performed arthroscopic rotator cuff repair with different techniques of suture anchor fixation and different PRP augmentation. The three studies found no difference in clinical rating scales and functional outcomes between PRP and control groups. Only one study showed clinical statistically significant difference between the two groups at the 3-month followup. Any statistically significant difference in the rates of tendon rerupture between the control group and the PRP group was found using the magnetic resonance imaging. The current literature on tissue engineering application for rotator cuff repair is scanty. Comparative studies included in this review suggest that PRP augmented repair of a rotator cuff does not yield improved functional and clinical outcome compared with non-augmented repair at a medium and long-term followup.

  14. DNA damage and repair activity after broccoli intake in young healthy smokers

    DEFF Research Database (Denmark)

    Riso, Patrizia; Martini, Daniela; Møller, Peter;

    2010-01-01

    Cruciferous vegetables contain compounds with antioxidant properties (e.g. carotenoids, vitamin C and folates) and can alter the activity of xenobiotic metabolism (i.e. isothiocyanates). These constituents may be particularly important for subjects who are exposed to free radicals and genotoxic....... Blood was collected before and after each period. The level of oxidatively damaged DNA lesions (formamidopyrimidine DNA glycosylase-sensitive sites), resistance to ex vivo H(2)O(2) treatment and repair of oxidised DNA lesions were measured in peripheral blood mononuclear cells (PBMCs). We also measured...

  15. Reduced inflammation accompanies diminished myelin damage and repair in the NG2 null mouse spinal cord

    Directory of Open Access Journals (Sweden)

    Kucharova Karolina

    2011-11-01

    Full Text Available Abstract Background Multiple sclerosis (MS is a demyelinating disease in which blood-derived immune cells and activated microglia damage myelin in the central nervous system. While oligodendrocyte progenitor cells (OPCs are essential for generating oligodendrocytes for myelin repair, other cell types also participate in the damage and repair processes. The NG2 proteoglycan is expressed by OPCs, pericytes, and macrophages/microglia. In this report we investigate the effects of NG2 on these cell types during spinal cord demyelination/remyelination. Methods Demyelinated lesions were created by microinjecting 1% lysolecithin into the lumbar spinal cord. Following demyelination, NG2 expression patterns in wild type mice were studied via immunostaining. Immunolabeling was also used in wild type and NG2 null mice to compare the extent of myelin damage, the kinetics of myelin repair, and the respective responses of OPCs, pericytes, and macrophages/microglia. Cell proliferation was quantified by studies of BrdU incorporation, and cytokine expression levels were evaluated using qRT-PCR. Results The initial volume of spinal cord demyelination in wild type mice is twice as large as in NG2 null mice. However, over the ensuing 5 weeks there is a 6-fold improvement in myelination in wild type mice, versus only a 2-fold improvement in NG2 null mice. NG2 ablation also results in reduced numbers of each of the three affected cell types. BrdU incorporation studies reveal that reduced cell proliferation is an important factor underlying NG2-dependent decreases in each of the three key cell populations. In addition, NG2 ablation reduces macrophage/microglial cell migration and shifts cytokine expression from a pro-inflammatory to anti-inflammatory phenotype. Conclusions Loss of NG2 expression leads to decreased proliferation of OPCs, pericytes, and macrophages/microglia, reducing the abundance of all three cell types in demyelinated spinal cord lesions. As a result

  16. Probing the molecular structures of plasma-damaged and surface-repaired low-k dielectrics.

    Science.gov (United States)

    Zhang, Xiaoxian; Myers, John N; Lin, Qinghuang; Bielefeld, Jeffery D; Chen, Zhan

    2015-10-21

    Fully understanding the effect and the molecular mechanisms of plasma damage and silylation repair on low dielectric constant (low-k) materials is essential to the design of low-k dielectrics with defined properties and the integration of low-k dielectrics into advanced interconnects of modern electronics. Here, analytical techniques including sum frequency generation vibrational spectroscopy (SFG), Fourier transform infrared spectroscopy (FTIR), contact angle goniometry (CA) and X-ray photoelectron spectroscopy (XPS) have been employed to provide a comprehensive characterization of the surface and bulk structure changes of poly(methyl)silsesquioxane (PMSQ) low-k thin films before and after O2 plasma treatment and silylation repair. O2 plasma treatment altered drastically both the molecular structures and water structures at the surfaces of the PMSQ film while no bulk structural change was detected. For example, ∼34% Si-CH3 groups were removed from the PMSQ surface, and the Si-CH3 groups at the film surface tilted toward the surface after the O2 plasma treatment. The oxidation by the O2 plasma made the PMSQ film surface more hydrophilic and thus enhanced the water adsorption at the film surface. Both strongly and weakly hydrogen bonded water were detected at the plasma-damaged film surface during exposure to water with the former being the dominate component. It is postulated that this enhancement of both chemisorbed and physisorbed water after the O2 plasma treatment leads to the degradation of low-k properties and reliability. The degradation of the PMSQ low-k film can be recovered by repairing the plasma-damaged surface using a silylation reaction. The silylation method, however, cannot fully recover the plasma induced damage at the PMSQ film surface as evidenced by the existence of hydrophilic groups, including C-O/C[double bond, length as m-dash]O and residual Si-OH groups. This work provides a molecular level picture on the surface structural changes of low

  17. DNA damage and its repair in Dictyostelium discoideum irradiated by health lamp light (UV-B)

    Energy Technology Data Exchange (ETDEWEB)

    Okaichi, K.; Kajitani, N.; Nakajima, K.; Nozu, K.; Ohnishi, T. (Nara Medical Univ., Kashihara (Japan))

    1989-07-01

    Irradiation by health lamp (HL) light (280-320 nm) more efficiently induced cell killing and mutation in a radiation sensitive mutant (TW8) of Dictyostelium discoideum as compared with the parental wild-type strain (NC4). This light as well as a germicidal lamp-light (254 nm) produced pyrimidine dimers. The dimers were removed from DNA molecules by excision repair in NC4, but more slowly in TW8. It is suggested that pyrimidine dimers are the main DNA damage caused by HL light in D. discoideum, and that this results in cell killing and induced mutation. (author).

  18. Human POLD1 modulates cell cycle progression and DNA damage repair

    OpenAIRE

    Song, Jing; Hong, Ping; Liu, Chengeng; Zhang, Yueqi; Wang, Jinling; Wang, Peichang

    2015-01-01

    Background The activity of eukaryotic DNA polymerase delta (Pol δ) plays an essential role in genome stability through its effects on DNA replication and repair. The p125 catalytic subunit of Pol δ is encoded by POLD1 gene in human cells. To clarify biological functions of POLD1, we investigated the effects of POLD1 overexpression or downregulation on cell proliferation, cell cycle progression, DNA synthesis and oxidative DNA damage induced by H2O2. Methods HEK293 cells were transfected with ...

  19. Digital Restoration from Start to Finish How to repair old and damaged photographs

    CERN Document Server

    Ctein,

    2010-01-01

    Digital Restoration: Start to Finish 2nd edition guides you step-by-step through the entire process of restoring old photographs and repairing new ones using Adobe Photoshop, Picture Window, and now Elements. Nothing is left out, from choosing the right hardware and software and getting the photographs into the computer, to getting the finished photo out of the computer and preserving it for posterity.  LEARN HOW TO: Scan faded and damaged prints or films Improve snapshots with Shadow/Highlight adjustment Correct uneven exposure Fix color and skin tones quickly with Curves, plug-ins, a

  20. Signaling molecules regulating phenotypic conversions of astrocytes and glial scar formation in damaged nerve tissues.

    Science.gov (United States)

    Koyama, Yutaka

    2014-12-01

    Phenotypic conversion of astrocytes from resting to reactive (i.e., astrocytic activation) occurs in numerous brain disorders. Astrocytic activation in severely damaged brain regions often leads to glial scar formation. Because astrocytic activation and glial scar largely affect the vulnerability and tissue repair of damaged brain, numerous studies have been made to clarify mechanisms regulating the astrocytic phenotype. The phenotypic conversion is accompanied by the increased expression of intermediate filament proteins and the induction of hypertrophy in reactive astrocytes. Severe brain damage results in proliferation and migration of reactive astrocytes, which lead to glial scar formations at the injured areas. Gliogenesis from neural progenitors in the adult brain is also involved in astrocytic activation and glial scar formation. Recent studies have shown that increased expression of connexin 43, aquaporin 4, matrix metalloproteinase 9, and integrins alter the function of astrocytes. The transcription factors: STAT3, OLIG2, SMAD, NF-κB, and Sp1 have been suggested to play regulatory roles in astrocytic activation and glial scar formation. In this review, I discuss the roles of these key molecules regulating the pathophysiological functions of reactive astrocytes.

  1. Modulation of tissue repair by regeneration enhancer elements.

    Science.gov (United States)

    Kang, Junsu; Hu, Jianxin; Karra, Ravi; Dickson, Amy L; Tornini, Valerie A; Nachtrab, Gregory; Gemberling, Matthew; Goldman, Joseph A; Black, Brian L; Poss, Kenneth D

    2016-04-14

    How tissue regeneration programs are triggered by injury has received limited research attention. Here we investigate the existence of enhancer regulatory elements that are activated in regenerating tissue. Transcriptomic analyses reveal that leptin b (lepb) is highly induced in regenerating hearts and fins of zebrafish. Epigenetic profiling identified a short DNA sequence element upstream and distal to lepb that acquires open chromatin marks during regeneration and enables injury-dependent expression from minimal promoters. This element could activate expression in injured neonatal mouse tissues and was divisible into tissue-specific modules sufficient for expression in regenerating zebrafish fins or hearts. Simple enhancer-effector transgenes employing lepb-linked sequences upstream of pro- or anti-regenerative factors controlled the efficacy of regeneration in zebrafish. Our findings provide evidence for 'tissue regeneration enhancer elements' (TREEs) that trigger gene expression in injury sites and can be engineered to modulate the regenerative potential of vertebrate organs.

  2. Hyaluronan and RHAMM in Wound Repair and the “Cancerization” of Stromal Tissues

    Directory of Open Access Journals (Sweden)

    Cornelia Tolg

    2014-01-01

    Full Text Available Tumors and wounds share many similarities including loss of tissue architecture, cell polarity and cell differentiation, aberrant extracellular matrix (ECM remodeling (Ballard et al., 2006 increased inflammation, angiogenesis, and elevated cell migration and proliferation. Whereas these changes are transient in repairing wounds, tumors do not regain tissue architecture but rather their continued progression is fueled in part by loss of normal tissue structure. As a result tumors are often described as wounds that do not heal. The ECM component hyaluronan (HA and its receptor RHAMM have both been implicated in wound repair and tumor progression. This review highlights the similarities and differences in their roles during these processes and proposes that RHAMM-regulated wound repair functions may contribute to “cancerization” of the tumor microenvironment.

  3. Evaluation of cartilage repair tissue after biomaterial implantation in rat patella by using T2 mapping.

    Science.gov (United States)

    Watrin-Pinzano, A; Ruaud, J-P; Cheli, Y; Gonord, P; Grossin, L; Bettembourg-Brault, I; Gillet, P; Payan, E; Guillot, G; Netter, P; Loeuille, D

    2004-12-01

    To evaluate the ability of MR T2 mapping (8.5 T) to characterize ex vivo longitudinally, morphologically and quantitatively, alginate-based tissue engineering in a rat model of patellar cartilage chondral focal defect. Calibrated rat patellar cartilage defects (1.3 mm) were created at day 0 (D0) and alginate sponge with (Sp/C+) or without (Sp/C-) autologous chondrocytes were implanted. Animals were sacrificed sequentially at D20, D40 and D60 after surgery and dissected patellae underwent MRI exploration (8.5 T). T2 values were calculated from eight SE images by using nonlinear least-squares curve fitting on a pixel-by-pixel basis (constant repetition time of 1.5 s, eight different echo times: 5.5, 7.5, 10.5, 12.5, 15.0, 20.0, 25.0 and 30.0 ms). On the T2 map, acquired in a transversal plane through the repair zone, global T2 values and zonal variation of T2 values of repair tissue were evaluated versus control group and compared with macroscopic score and histological studies (toluidine blue, sirius red and hematoxylin-eosin). "Partial", "total" and "hypertrophic" repair patterns were identified. At D40 and D60, Sp/C+ group was characterized by a higher proportion of "total" repair in comparison to Sp/C- group. At D60, the proportion of "hypertrophic" repair was two fold in Sp/C- group versus Sp/C+ group. As confirmed morphologically and histologically, the T2 map also permitted the distinction of three types of repair tissue: "total", "partial" and "hypertrophic". "Total" repair tissue was characterized by high T2 values versus normal cartilage (p<0.05). Zonal variation, reflecting the collagen network organization, appeared only at D60 for Sp/C+ group (p<0.05). "Hypertrophic" tissue, mainly observed at D60, presented high T2 global values without zonal variation with cartilage depth. These results confirm the potency of the MR T2 map (8.5 T) to characterize macroscopically and microscopically the patterns of the scaffold guided-tissue repair of a focal chondral

  4. Tissue-engineered tendon constructs for rotator cuff repair in sheep.

    Science.gov (United States)

    Novakova, Stoyna S; Mahalingam, Vasudevan D; Florida, Shelby E; Mendias, Christopher L; Allen, Answorth; Arruda, Ellen M; Bedi, Asheesh; Larkin, Lisa M

    2017-06-28

    Current rotator cuff repair commonly involves the use of single or double row suture techniques, and despite successful outcomes, failure rates continue to range from 20 to 95%. Failure to regenerate native biomechanical properties at the enthesis is thought to contribute to failure rates. Thus, the need for technologies that improve structural healing of the enthesis after rotator cuff repair is imperative. To address this issue, our lab has previously demonstrated enthesis regeneration using a tissue-engineered graft approach in a sheep anterior cruciate ligament (ACL) repair model. We hypothesized that our tissue-engineered graft designed for ACL repair also will be effective in rotator cuff repair. The goal of this study was to test the efficacy of our Engineered Tissue Graft for Rotator Cuff (ETG-RC) in a rotator cuff tear model in sheep and compare this novel graft technology to the commonly used double row suture repair technique. Following a 6-month recovery, the grafted and contralateral shoulders were removed, imaged using X-ray, and tested biomechanically. Additionally, the infraspinatus muscle, myotendinous junction, enthesis, and humeral head were preserved for histological analysis of muscle, tendon, and enthesis structure. Our results showed that our ETC-RCs reached 31% of the native tendon tangent modulus, which was a modest, non-significant, 11% increase over that of the suture-only repairs. However, the histological analysis showed the regeneration of a native-like enthesis in the ETG-RC-repaired animals. This advanced structural healing may improve over longer times and may diminish recurrence rates of rotator cuff tears and lead to better clinical outcomes. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc. J Orthop Res. © 2017 Orthopaedic Research Society. Published by Wiley Periodicals, Inc.

  5. Cartilage repair: surgical techniques and tissue engineering using polysaccharide- and collagen-based biomaterials.

    Science.gov (United States)

    Galois, L; Freyria, A M; Grossin, L; Hubert, P; Mainard, D; Herbage, D; Stoltz, J F; Netter, P; Dellacherie, E; Payan, E

    2004-01-01

    Lesions of articular cartilage have a large variety of causes among which traumatic damage, osteoarthritis and osteochondritis dissecans are the most frequent. Replacement of articular defects in joints has assumed greater importance in recent years. This interest results in large part because cartilage defects cannot adequately heal themselves. Many techniques have been suggested over the last 30 years, but none allows the regeneration of the damaged cartilage, i.e. its replacement by a strictly identical tissue. In the first generation of techniques, relief of pain was the main concern, which could be provided by techniques in which cartilage was replaced by fibrocartilage. Disappointing results led investigators to focus on more appropriate bioregenerative approaches using transplantation of autologous cells into the lesion. Unfortunately, none of these approaches has provided a perfect final solution to the problem. The latest generation of techniques, currently in the developmental or preclinical stages, involve biomaterials for the repair of chondral or osteochondral lesions. Many of these scaffolds are designed to be seeded with chondrocytes or progenitor cells. Among natural and synthetic polymers, collagen- and polysaccharide-based biomaterials have been extensively used. For both these supports, studies have shown that chondrocytes maintain their phenotype when cultured in three dimensions. In both types of culture, a glycosaminoglycan-rich deposit is formed on the surface and in the inner region of the cultured cartilage, and type II collagen synthesis is also observed. Dynamic conditions can also improve the composition of such three-dimensional constructs. Many improvements are still required, however, in a number of key aspects that so far have received only scant attention. These aspects include: adhesion/integration of the graft with the adjacent native cartilage, cell-seeding with genetically-modified cell populations, biomaterials that can be

  6. DNA damage and radical reactions: Mechanistic aspects, formation in cells and repair studies

    Energy Technology Data Exchange (ETDEWEB)

    Cadet, J.; Ravanat, J.L. [CEA Grenoble, Inst Nanosci and Cryogenie, SCIB-UMR-E 3, Lab Les Acides Nucl, UJF, F-38054 Grenoble 9 (France); Carell, T. [Univ Munich, Dept Chem and Biochem, Ctr Integrat Prot Sci, D-81377 Munich (Germany); Cellai, L. [CNR, Ist Cristalog, Monterotondo Stn, I-00016 Rome (Italy); Chatgilialoglu, Ch. [CNR, ISOF, I-40129 Bologna, (Italy); Gimisis, Th. [Univ Athens, Dept Chem, Organ Chem Lab, Athens 15784, (Greece); Miranda, M. [Univ Politecn Valencia, Inst Technol Quim, Dept Quim, Valencia 46022 (Spain); O' Neill, P. [Univ Oxford, Oxford OX3 7DQ (United Kingdom); Robert, M. [Univ Paris 07, CNRS, UMR 7591, Electrochim Mol Lab, F-75251 Paris 05 (France)

    2008-07-01

    Several examples of oxidative and reductive reactions of DNA components that lead to single and tandem modifications are discussed in this review. These include nucleophilic addition reactions of the one-electron oxidation-mediated guanine radical cation and the one-electron reduced intermediate of 8-bromo-purine 2'-de-oxy-ribo-nucleosides that give rise to either an oxidizing guanine radical or related 5',8-cyclo-purine nucleosides. In addition, mechanistic insights into the reductive pathways involved in the photolyase induced reversal of cyclo-buta-cli-pyrimidine and pyrimidine (6-4) pyrimidone photoproducts are provided. Evidence for the occurrence and validation in cellular DNA of (OH){sup {center_dot}} radical degradation pathways of guanine that have been established in model systems has been gained from the accurate measurement of degradation products. Relevant information on biochemical aspects of the repair of single and clustered oxidatively generated damage to DNA has been gained from detailed investigations that rely on the synthesis of suitable modified probes. Thus the preparation of stable carbocyclic derivatives of purine nucleoside containing defined sequence oligonucleotides has allowed detailed crystallographic studies of the recognition step of the base damage by enzymes implicated in the base excision repair (BER) pathway. Detailed insights are provided on the BER processing of non-double strand break bi-stranded clustered damage that may consist of base lesions, a single strand break or abasic sites and represent one of the main deleterious classes of radiation-induced DNA damage. (authors)

  7. Oxidative stress and DNA damage signalling in skeletal muscle in pressure-induced deep tissue injury.

    Science.gov (United States)

    Sin, Thomas K; Pei, Xiao M; Teng, Bee T; Tam, Eric W; Yung, Benjamin Y; Siu, Parco M

    2013-02-01

    The molecular mechanisms that contribute to the pathogenesis of pressure-induced deep tissue injury are largely unknown. This study tested the hypothesis that oxidative stress and DNA damage signalling mechanism in skeletal muscle are involved in deep tissue injury. Adult Sprague Dawley rats were subject to an experimental protocol to induce deep tissue injury. Two compression cycles with a static pressure of 100 mmHg was applied to an area of 1.5 cm(2) over the mid-tibialis region of right limb of the rats. The left uncompressed limb served as intra-animal control. Muscle tissues underneath compression region were collected for examination. Our analyses indicated that pathohistological characteristics including rounding contour of myofibres and extensive nuclei accumulation were apparently shown in compressed muscles. The elevation of 8OHdG immunopositively stained nuclei indicated the presence of oxidative DNA damage. Increase in oxidative stress was revealed by showing significant elevation of 4HNE and decreases in mRNA abundance of SOD1, catalase and GPx, and protein content of SOD2 in compressed muscles relative to control muscles. Increase in nitrosative stress was demonstrated by significant elevation of nitrotyrosine and NOS2 mRNA content. The activation of tumor suppressor p53 signalling was indicated by the remarkable increases in protein contents of total p53 and serine-15 phosphorylated p53. The transcript expression of the DNA-repairing enzyme, Rad23A, was significantly suppressed in compressed muscles. Our time-course study indicated that increased oxidative/nitrosative stress and proapoptotic signalling were maintained in muscles receiving increasing amount of compression cycles and post-compression time. Furthermore, resveratrol was found to attenuate the histological damage, oxidative/nitrosative stress and proapoptotic signalling in response to prolonged moderate compression. In conclusion, our findings are consistent with the hypothesis that

  8. Discovery of Novel Small Molecules that Activate Satellite Cell Proliferation and Enhance Repair of Damaged Muscle.

    Science.gov (United States)

    Billin, Andrew N; Bantscheff, Marcus; Drewes, Gerard; Ghidelli-Disse, Sonja; Holt, Jason A; Kramer, Henning F; McDougal, Alan J; Smalley, Terry L; Wells, Carrow I; Zuercher, William J; Henke, Brad R

    2016-02-19

    Skeletal muscle progenitor stem cells (referred to as satellite cells) represent the primary pool of stem cells in adult skeletal muscle responsible for the generation of new skeletal muscle in response to injury. Satellite cells derived from aged muscle display a significant reduction in regenerative capacity to form functional muscle. This decrease in functional recovery has been attributed to a decrease in proliferative capacity of satellite cells. Hence, agents that enhance the proliferative abilities of satellite cells may hold promise as therapies for a variety of pathological settings, including repair of injured muscle and age- or disease-associated muscle wasting. Through phenotypic screening of isolated murine satellite cells, we identified a series of 2,4-diaminopyrimidines (e.g., 2) that increased satellite cell proliferation. Importantly, compound 2 was effective in accelerating repair of damaged skeletal muscle in an in vivo mouse model of skeletal muscle injury. While these compounds were originally prepared as c-Jun N-terminal kinase 1 (JNK-1) inhibitors, structure-activity analyses indicated JNK-1 inhibition does not correlate with satellite cell activity. Screening against a broad panel of kinases did not result in identification of an obvious molecular target, so we conducted cell-based proteomics experiments in an attempt to identify the molecular target(s) responsible for the potentiation of the satellite cell proliferation. These data provide the foundation for future efforts to design improved small molecules as potential therapeutics for muscle repair and regeneration.

  9. A tissue regeneration approach to bone and cartilage repair

    CERN Document Server

    Dunstan, Colin; Rosen, Vicki

    2015-01-01

    Reviewing exhaustively the current state of the art of tissue engineering strategies for regenerating bones and joints through the use of biomaterials, growth factors and stem cells, along with an investigation of the interactions between biomaterials, bone cells, growth factors and added stem cells and how together skeletal tissues can be optimised, this book serves to highlight the importance of biomaterials composition, surface topography, architectural and mechanical properties in providing support for tissue regeneration. Maximizing reader insights into the importance of the interplay of these attributes with bone cells (osteoblasts, osteocytes and osteoclasts) and cartilage cells (chondrocytes), this book also provides a detailed reference as to how key signalling pathways are activated. The contribution of growth factors to drive tissue regeneration and stem cell recruitment is discussed along with a review the potential and challenges of adult or embryonic mesenchymal stem cells to further enhance the...

  10. Histone deacetylase inhibitors mediate DNA damage repair in ameliorating hemorrhagic cystitis.

    Science.gov (United States)

    Haldar, Subhash; Dru, Christopher; Mishra, Rajeev; Tripathi, Manisha; Duong, Frank; Angara, Bryan; Fernandez, Ana; Arditi, Moshe; Bhowmick, Neil A

    2016-12-20

    Hemorrhagic cystitis is an inflammatory and ulcerative bladder condition associated with systemic chemotherapeutics, like cyclophosphomide. Earlier, we reported reactive oxygen species resulting from cyclophosphamide metabolite, acrolein, causes global methylation followed by silencing of DNA damage repair genes. Ogg1 (8-oxoguanine DNA glycosylase) is one such silenced base excision repair enzyme that can restore DNA integrity. The accumulation of DNA damage results in subsequent inflammation associated with pyroptotic death of bladder smooth muscle cells. We hypothesized that reversing inflammasome-induced imprinting in the bladder smooth muscle could prevent the inflammatory phenotype. Elevated recruitment of Dnmt1 and Dnmt3b to the Ogg1 promoter in acrolein treated bladder muscle cells was validated by the pattern of CpG methylation revealed by bisulfite sequencing. Knockout of Ogg1 in detrusor cells resulted in accumulation of reactive oxygen mediated 8-Oxo-dG and spontaneous pyroptotic signaling. Histone deacetylase (HDAC) inhibitor, suberoylanilide hydroxamic acid (SAHA), restored Ogg1 expression in cells treated with acrolein and mice treated with cyclophosphamide superior to the standard of care, mesna or nicotinamide-induced DNA demethylation. SAHA restored cyclophosphamide-induced bladder pathology to that of untreated control mice. The observed epigenetic imprinting induced by inflammation suggests a new therapeutic target for the treatment of hemorrhagic cystitis.

  11. Real-time fluorescence imaging of the DNA damage repair response during mitosis.

    Science.gov (United States)

    Miwa, Shinji; Yano, Shuya; Yamamoto, Mako; Matsumoto, Yasunori; Uehara, Fuminari; Hiroshima, Yukihiko; Toneri, Makoto; Murakami, Takashi; Kimura, Hiroaki; Hayashi, Katsuhiro; Yamamoto, Norio; Efimova, Elena V; Tsuchiya, Hiroyuki; Hoffman, Robert M

    2015-04-01

    The response to DNA damage during mitosis was visualized using real-time fluorescence imaging of focus formation by the DNA-damage repair (DDR) response protein 53BP1 linked to green fluorescent protein (GFP) (53BP1-GFP) in the MiaPaCa-2(Tet-On) pancreatic cancer cell line. To observe 53BP1-GFP foci during mitosis, MiaPaCa-2(Tet-On) 53BP1-GFP cells were imaged every 30 min by confocal microscopy. Time-lapse imaging demonstrated that 11.4 ± 2.1% of the mitotic MiaPaCa-2(Tet-On) 53BP1-GFP cells had increased focus formation over time. Non-mitotic cells did not have an increase in 53BP1-GFP focus formation over time. Some of the mitotic MiaPaCa-2(Tet-On) 53BP1-GFP cells with focus formation became apoptotic. The results of the present report suggest that DNA strand breaks occur during mitosis and undergo repair, which may cause some of the mitotic cells to enter apoptosis in a phenomenon possibly related to mitotic catastrophe.

  12. Histone deacetylase inhibitors mediate DNA damage repair in ameliorating hemorrhagic cystitis

    Science.gov (United States)

    Haldar, Subhash; Dru, Christopher; Mishra, Rajeev; Tripathi, Manisha; Duong, Frank; Angara, Bryan; Fernandez, Ana; Arditi, Moshe; Bhowmick, Neil A.

    2016-01-01

    Hemorrhagic cystitis is an inflammatory and ulcerative bladder condition associated with systemic chemotherapeutics, like cyclophosphomide. Earlier, we reported reactive oxygen species resulting from cyclophosphamide metabolite, acrolein, causes global methylation followed by silencing of DNA damage repair genes. Ogg1 (8-oxoguanine DNA glycosylase) is one such silenced base excision repair enzyme that can restore DNA integrity. The accumulation of DNA damage results in subsequent inflammation associated with pyroptotic death of bladder smooth muscle cells. We hypothesized that reversing inflammasome-induced imprinting in the bladder smooth muscle could prevent the inflammatory phenotype. Elevated recruitment of Dnmt1 and Dnmt3b to the Ogg1 promoter in acrolein treated bladder muscle cells was validated by the pattern of CpG methylation revealed by bisulfite sequencing. Knockout of Ogg1 in detrusor cells resulted in accumulation of reactive oxygen mediated 8-Oxo-dG and spontaneous pyroptotic signaling. Histone deacetylase (HDAC) inhibitor, suberoylanilide hydroxamic acid (SAHA), restored Ogg1 expression in cells treated with acrolein and mice treated with cyclophosphamide superior to the standard of care, mesna or nicotinamide-induced DNA demethylation. SAHA restored cyclophosphamide-induced bladder pathology to that of untreated control mice. The observed epigenetic imprinting induced by inflammation suggests a new therapeutic target for the treatment of hemorrhagic cystitis. PMID:27995963

  13. DNA Damage/Repair and Polymorphism of the hOGG1 Gene in Lymphocytes of AMD Patients

    Directory of Open Access Journals (Sweden)

    Katarzyna Wozniak

    2009-01-01

    Full Text Available Oxidative stress is thought to play a role in the pathogenesis of age-related macular degeneration (AMD. We determined the extent of oxidative DNA damage and the kinetics of its removal as well as the genotypes of the Ser326Cys polymorphism of the hOGG1 gene in lymphocytes of 30 wet AMD patients and 30 controls. Oxidative DNA damage induced by hydrogen peroxide and its repair were evaluated by the comet assay and DNA repair enzymes. We observed a higher extent of endogenous oxidative DNA damage and a lower efficacy of its repair in AMD patients as compared with the controls. We did not find any correlation between the extent of DNA damage and efficacy of DNA repair with genotypes of the Ser326Cys polymorphism. The results obtained suggest that oxidative DNA damage and inefficient DNA repair can be associated with AMD and the variability of the hOOG1 gene may not contribute to this association.

  14. The Molecular Mechanisms and the Role of hnRNP K Protein Post- Translational Modification in DNA Damage Repair.

    Science.gov (United States)

    Lu, Jing; Gao, Feng-Hou

    2017-01-01

    DNA damage repair is a kind of cellular self-protection mechanism in which some relevant proteins are activated when DNA damage response occurs in order to maintain the intracellular function stability and structure integrity. Post-translational modifications (PTMs) of proteins can rapidly confer to them more complicated structure and sophisticated function by covalently combining different small molecules with target proteins, which in turn plays an important regulatory role in DNA damage repair. It was reported that heterogeneous nuclear ribonucleoprotein K (hnRNP K) could be involved in DNA damage repair process under the regulation of its many post-translational modifications, including methylation, ubiquitination, sumoylation and phosphorylation. Here, we reviewed molecular mechanisms of hnRNP K protein post-translational modifications and their role in DNA damage repair, which will promote our understanding of how hnRNP K participating in the repair process to maintain the normal operation of biological activities in the cells. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

  15. DNA damage induced by boron neutron capture therapy is partially repaired by DNA ligase IV.

    Science.gov (United States)

    Kondo, Natsuko; Sakurai, Yoshinori; Hirota, Yuki; Tanaka, Hiroki; Watanabe, Tsubasa; Nakagawa, Yosuke; Narabayashi, Masaru; Kinashi, Yuko; Miyatake, Shin-ichi; Hasegawa, Masatoshi; Suzuki, Minoru; Masunaga, Shin-ichiro; Ohnishi, Takeo; Ono, Koji

    2016-03-01

    Boron neutron capture therapy (BNCT) is a particle radiation therapy that involves the use of a thermal or epithermal neutron beam in combination with a boron ((10)B)-containing compound that specifically accumulates in tumor. (10)B captures neutrons and the resultant fission reaction produces an alpha ((4)He) particle and a recoiled lithium nucleus ((7)Li). These particles have the characteristics of high linear energy transfer (LET) radiation and therefore have marked biological effects. High-LET radiation is a potent inducer of DNA damage, specifically of DNA double-strand breaks (DSBs). The aim of the present study was to clarify the role of DNA ligase IV, a key player in the non-homologous end-joining repair pathway, in the repair of BNCT-induced DSBs. We analyzed the cellular sensitivity of the mouse embryonic fibroblast cell lines Lig4-/- p53-/- and Lig4+/+ p53-/- to irradiation using a thermal neutron beam in the presence or absence of (10)B-para-boronophenylalanine (BPA). The Lig4-/- p53-/- cell line had a higher sensitivity than the Lig4+/+ p53-/-cell line to irradiation with the beam alone or the beam in combination with BPA. In BNCT (with BPA), both cell lines exhibited a reduction of the 50 % survival dose (D 50) by a factor of 1.4 compared with gamma-ray and neutron mixed beam (without BPA). Although it was found that (10)B uptake was higher in the Lig4+/+ p53-/- than in the Lig4-/- p53-/- cell line, the latter showed higher sensitivity than the former, even when compared at an equivalent (10)B concentration. These results indicate that BNCT-induced DNA damage is partially repaired using DNA ligase IV.

  16. Tissue engineering and the use of stem/progenitor cells for airway epithelium repair

    Directory of Open Access Journals (Sweden)

    GM Roomans

    2010-06-01

    Full Text Available Stem/progenitor cells can be used to repair defects in the airway wall, resulting from e.g., tumors, trauma, tissue reactions following long-time intubations, or diseases that are associated with epithelial damage. Several potential sources of cells for airway epithelium have been identified. These can be divided into two groups. The first group consists of endogenous progenitor cells present in the respiratory tract. This group can be subdivided according to location into (a a ductal cell type in the submucosal glands of the proximal trachea, (b basal cells in the intercartilaginous zones of the lower trachea and bronchi, (c variant Clara cells (Clarav-cells in the bronchioles and (d at the junctions between the bronchioles and the alveolar ducts, and (e alveolar type II cells. This classification of progenitor cell niches is, however, controversial. The second group consists of exogenous stem cells derived from other tissues in the body. This second group can be subdivided into: (a embryonic stem (ES cells, induced pluripotent stem (iPS cells, or amniotic fluid stem cells, (b side-population cells from bone marrow or epithelial stem cells present in bone marrow or circulation and (c fat-derived mesenchymal cells. Airway epithelial cells can be co-cultured in a system that includes a basal lamina equivalent, extracellular factors from mesenchymal fibroblasts, and in an air-liquid interface system. Recently, spheroid-based culture systems have been developed. Several clinical applications have been suggested: cystic fibrosis, acute respiratory distress syndrome, chronic obstructive lung disease, pulmonary fibrosis, pulmonary edema, and pulmonary hypertension. Clinical applications so far are few, but include subglottic stenosis, tracheomalacia, bronchiomalacia, and emphysema.

  17. Full incorporation of Strattice™ Reconstructive Tissue Matrix in a reinforced hiatal hernia repair: a case report

    Directory of Open Access Journals (Sweden)

    Freedman Bruce E

    2012-08-01

    Full Text Available Abstract Introduction A non-cross-linked porcine acellular dermal matrix was used to reinforce an esophageal hiatal hernia repair. A second surgery was required 11 months later to repair a slipped Nissen; this allowed for examination of the hiatal hernia repair and showed the graft to be well vascularized and fully incorporated. Case presentation A 71-year-old Caucasian woman presented with substernal burning and significant dysphagia. An upper gastrointestinal series revealed a type III complex paraesophageal hiatal hernia. She underwent laparoscopic surgery to repair a hiatal hernia that was reinforced with a xenograft (Strattice™ Reconstructive Tissue Matrix, LifeCell, Branchburg, NJ, USA along with a Nissen fundoplication. A second surgery was required to repair a slipped Nissen; this allowed for examination of the hiatal repair and graft incorporation 11 months after the initial surgery. Conclusion In this case, a porcine acellular dermal matrix was an effective tool to reinforce the crural hiatal hernia repair. The placement of the mesh and method of fixation are believed to be crucial to the success of the graft. It was found to be well vascularized 11 months after the original placement with no signs of erosion, stricture, or infection. Further studies and long-term follow-up are required to support the findings of this case report.

  18. 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)

  19. Process-induced extracellular matrix alterations affect the mechanisms of soft tissue repair and regeneration

    Directory of Open Access Journals (Sweden)

    Wendell Q Sun

    2013-09-01

    Full Text Available Extracellular matrices derived from animal tissues for human tissue repairs are processed by various methods of physical, chemical, or enzymatic decellularization, viral inactivation, and terminal sterilization. The mechanisms of action in tissue repair vary among bioscaffolds and are suggested to be associated with process-induced extracellular matrix modifications. We compared three non-cross-linked, commercially available extracellular matrix scaffolds (Strattice, Veritas, and XenMatrix, and correlated extracellular matrix alterations to in vivo biological responses upon implantation in non-human primates. Structural evaluation showed significant differences in retaining native tissue extracellular matrix histology and ultrastructural features among bioscaffolds. Tissue processing may cause both the condensation of collagen fibers and fragmentation or separation of collagen bundles. Calorimetric analysis showed significant differences in the stability of bioscaffolds. The intrinsic denaturation temperature was measured to be 51°C, 38°C, and 44°C for Strattice, Veritas, and XenMatrix, respectively, demonstrating more extracellular matrix modifications in the Veritas and XenMatrix scaffolds. Consequently, the susceptibility to collagenase degradation was increased in Veritas and XenMatrix when compared to their respective source tissues. Using a non-human primate model, three bioscaffolds were found to elicit different biological responses, have distinct mechanisms of action, and yield various outcomes of tissue repair. Strattice permitted cell repopulation and was remodeled over 6 months. Veritas was unstable at body temperature, resulting in rapid absorption with moderate inflammation. XenMatrix caused severe inflammation and sustained immune reactions. This study demonstrates that extracellular matrix alterations significantly affect biological responses in soft tissue repair and regeneration. The data offer useful insights into the

  20. Investigations of DNA damage induction and repair resulting from cellular exposure to high dose-rate pulsed proton beams

    Energy Technology Data Exchange (ETDEWEB)

    Renis, M.; Malfa, G.; Tomasello, B. [Drug Sciences Department, University of Catania, Catania (Italy); Borghesi, M.; Schettino, G. [Queen' s University Belfast, Northern Ireland (United Kingdom); Favetta, M.; Romano, F.; Cirrone, G. A. P. [National Institute for Nuclear Physics (INFN-LNS), Catania (Italy); Manti, L. [Physics Science Department, University of Naples Federico II, Naples, and National Institute for Nuclear Physics (INFN), Naples (Italy)

    2013-07-26

    Studies regarding the radiobiological effects of low dose radiation, microbeam irradiation services have been developed in the world and today laser acceleration of protons and heavy ions may be used in radiation therapy. The application of different facilities is essential for studying bystander effects and relating signalling phenomena in different cells or tissues. In particular the use of ion beams results advantageous in cancer radiotherapy compared to more commonly used X-rays, since the ability of ions in delivering lethal amount of doses into the target tumour avoiding or limiting damage to the contiguous healthy tissues. At the INFN-LNS in Catania, a multidisciplinary radiobiology group is strategically structured aimed to develop radiobiological research, finalised to therapeutic applications, compatible with the use of high dose laser-driven ion beams. The characteristic non-continuous dose rates with several orders of magnitude of laser-driven ion beams makes this facility very interesting in the cellular systems' response to ultra-high dose rates with non-conventional pulse time intervals cellular studies. Our group have projected to examine the effect of high dose laser-driven ion beams on two cellular types: foetal fibroblasts (normal control cells) and DU145 (prostate cancer cells), studying the modulation of some different bio-molecular parameters, in particular cell proliferation and viability, DNA damage, redox cellular status, morphological alterations of both the cytoskeleton components and some cell organelles and the possible presence of apoptotic or necrotic cell death. Our group performed preliminary experiments with high energy (60 MeV), dose rate of 10 Gy/min, doses of 1, 2, 3 Gy and LET 1 keV/μm on human foetal fibroblasts (control cells). We observed that cell viability was not influenced by the characteristics of the beam, the irradiation conditions or the analysis time. Conversely, DNA damage was present at time 0, immediately

  1. Adaptive growth factor delivery from a polyelectrolyte coating promotes synergistic bone tissue repair and reconstruction.

    Science.gov (United States)

    Shah, Nisarg J; Hyder, Md Nasim; Quadir, Mohiuddin A; Dorval Courchesne, Noémie-Manuelle; Seeherman, Howard J; Nevins, Myron; Spector, Myron; Hammond, Paula T

    2014-09-01

    Traumatic wounds and congenital defects that require large-scale bone tissue repair have few successful clinical therapies, particularly for craniomaxillofacial defects. Although bioactive materials have demonstrated alternative approaches to tissue repair, an optimized materials system for reproducible, safe, and targeted repair remains elusive. We hypothesized that controlled, rapid bone formation in large, critical-size defects could be induced by simultaneously delivering multiple biological growth factors to the site of the wound. Here, we report an approach for bone repair using a polyelectrolye multilayer coating carrying as little as 200 ng of bone morphogenetic protein-2 and platelet-derived growth factor-BB that were eluted over readily adapted time scales to induce rapid bone repair. Based on electrostatic interactions between the polymer multilayers and growth factors alone, we sustained mitogenic and osteogenic signals with these growth factors in an easily tunable and controlled manner to direct endogenous cell function. To prove the role of this adaptive release system, we applied the polyelectrolyte coating on a well-studied biodegradable poly(lactic-co-glycolic acid) support membrane. The released growth factors directed cellular processes to induce bone repair in a critical-size rat calvaria model. The released growth factors promoted local bone formation that bridged a critical-size defect in the calvaria as early as 2 wk after implantation. Mature, mechanically competent bone regenerated the native calvaria form. Such an approach could be clinically useful and has significant benefits as a synthetic, off-the-shelf, cell-free option for bone tissue repair and restoration.

  2. Dynamics and mechanism of UV-damaged DNA repair in indole-thymine dimer adduct: molecular origin of low repair quantum efficiency.

    Science.gov (United States)

    Guo, Xunmin; Liu, Zheyun; Song, Qinhua; Wang, Lijuan; Zhong, Dongping

    2015-02-26

    Many biomimetic chemical systems for repair of UV-damaged DNA showed very low repair efficiency, and the molecular origin is still unknown. Here, we report our systematic characterization of the repair dynamics of a model compound of indole-thymine dimer adduct in three solvents with different polarity. By resolving all elementary steps including three electron-transfer processes and two bond-breaking and bond-formation dynamics with femtosecond resolution, we observed the slow electron injection in 580 ps in water, 4 ns in acetonitrile, and 1.38 ns in dioxane, the fast back electron transfer without repair in 120, 150, and 180 ps, and the slow bond splitting in 550 ps, 1.9 ns, and 4.5 ns, respectively. The dimer bond cleavage is clearly accelerated by the solvent polarity. By comparing with the biological repair machine photolyase with a slow back electron transfer (2.4 ns) and a fast bond cleavage (90 ps), the low repair efficiency in the biomimetic system is mainly determined by the fast back electron transfer and slow bond breakage. We also found that the model system exists in a dynamic heterogeneous C-clamped conformation, leading to a stretched dynamic behavior. In water, we even identified another stacked form with ultrafast cyclic electron transfer, significantly reducing the repair efficiency. Thus, the comparison of the repair efficiency in different solvents is complicated and should be cautious, and only the dynamics by resolving all elementary steps can finally determine the total repair efficiency. Finally, we use the Marcus electron-transfer theory to analyze all electron-transfer reactions and rationalize all observed electron-transfer dynamics.

  3. Biological consequences of potential repair intermediates of clustered base damage site in Escherichia coli

    Energy Technology Data Exchange (ETDEWEB)

    Shikazono, Naoya, E-mail: shikazono.naoya@jaea.go.jp [Japan Atomic Energy Agency, Advanced Research Science Center, 2-4 Shirakata-Shirane, Tokai-mura, Naka-gun, Ibaraki 319-1195 (Japan); O' Neill, Peter [Gray Institute for Radiation Oncology and Biology, University of Oxford, Roosevelt Drive, Oxford OX3 7DQ (United Kingdom)

    2009-10-02

    Clustered DNA damage induced by a single radiation track is a unique feature of ionizing radiation. Using a plasmid-based assay in Escherichia coli, we previously found significantly higher mutation frequencies for bistranded clusters containing 7,8-dihydro-8-oxoguanine (8-oxoG) and 5,6-dihydrothymine (DHT) than for either a single 8-oxoG or a single DHT in wild type and in glycosylase-deficient strains of E. coli. This indicates that the removal of an 8-oxoG from a clustered damage site is most likely retarded compared to the removal of a single 8-oxoG. To gain further insights into the processing of bistranded base lesions, several potential repair intermediates following 8-oxoG removal were assessed. Clusters, such as DHT + apurinic/apyrimidinic (AP) and DHT + GAP have relatively low mutation frequencies, whereas clusters, such as AP + AP or GAP + AP, significantly reduce the number of transformed colonies, most probably through formation of a lethal double strand break (DSB). Bistranded AP sites placed 3' to each other with various interlesion distances also blocked replication. These results suggest that bistranded base lesions, i.e., single base lesions on each strand, but not clusters containing only AP sites and strand breaks, are repaired in a coordinated manner so that the formation of DSBs is avoided. We propose that, when either base lesion is initially excised from a bistranded base damage site, the remaining base lesion will only rarely be converted into an AP site or a single strand break in vivo.

  4. Development and Evaluation of Cement-Based Materials for Repair of Corrosion-Damaged Reinforced Concrete Slabs

    OpenAIRE

    Liu, Rongtang; Olek, J.

    2001-01-01

    In this study, the results of an extensive laboratory investigation conducted to evaluate the properties of concrete mixes used as patching materials to repair reinforced concrete slabs damaged by corrosion are reported. Seven special concrete mixes containing various combinations of chemical or mineral admixtures were developed and used as a patching material to improve the durability of the repaired slabs. Physical and mechanical properties of these mixes, such as compressive strength, stat...

  5. Participation of gap junction communication in potentially lethal damage repair and DNA damage in human fibroblasts exposed to low- or high-LET radiation

    Science.gov (United States)

    Autsavapromporn, Narongchai; Suzuki, Masao; Plante, Ianik; Liu, Cuihua; Uchihori, Yukio; Hei, Tom K.; Azzam, Edouard I.; Murakami, Takeshi

    2014-01-01

    Existing research has not fully explained how different types of ionizing radiation (IR) modulate the responses of cell populations or tissues. In our previous work, we showed that gap junction intercellular communication (GJIC) mediates the propagation of stressful effects among irradiated cells exposed to high linear energy transfer (LET) radiations, in which almost every cells is traversed by an IR track. In the present study, we conducted an in-depth study of the role of GJIC in modulating the repair of potentially lethal damage (PLDR) and micronuclei formation in cells exposed to low- or high-LET IR. Confluent human fibroblasts were exposed in the presence or absence of a gap junction inhibitor to 200 kV X rays (LET ∼ 1.7 keV/µm), carbon ions (LET ∼ 76 keV/µm), silicon ions (LET ∼ 113 keV/µm) or iron ions (LET ∼ 400 keV/µm) that resulted in isosurvival levels. The fibroblasts were incubated for various times at 37 °C. As expected, high-LET IR were more effective than were low-LET X rays at killing cells and damaging DNA shortly after irradiation. However, when cells were held in a confluent state for several hours, PLDR associated with a reduction in DNA damage, occurred only in cells exposed to X rays. Interestingly, inhibition of GJIC eliminated the enhancement of toxic effects, which resulted in an increase of cell survival and reduction in the level of micronucleus formation in cells exposed to high, but not in those exposed to low-LET IR. The experiment shows that gap-junction communication plays an important role in the propagation of stressful effects among irradiated cells exposed to high-LET IR while GJIC has only a minimal effect on PLDR and DNA damage following low-LET irradiation. Together, our results show that PLDR and induction of DNA damage clearly depend on gap-junction communication and radiation quality. PMID:23867854

  6. p38γ regulates UV-induced checkpoint signaling and repair of UV-induced DNA damage.

    Science.gov (United States)

    Wu, Chia-Cheng; Wu, Xiaohua; Han, Jiahuai; Sun, Peiqing

    2010-06-01

    In eukaryotic cells, DNA damage triggers activation of checkpoint signaling pathways that coordinate cell cycle arrest and repair of damaged DNA. These DNA damage responses serve to maintain genome stability and prevent accumulation of genetic mutations and development of cancer. The p38 MAPK was previously implicated in cellular responses to several types of DNA damage. However, the role of each of the four p38 isoforms and the mechanism for their involvement in DNA damage responses remained poorly understood. In this study, we demonstrate that p38γ, but not the other p38 isoforms, contributes to the survival of UV-treated cells. Deletion of p38γ sensitizes cells to UV exposure, accompanied by prolonged S phase cell cycle arrest and increased rate of apoptosis. Further investigation reveal that p38γ is essential for the optimal activation of the checkpoint signaling caused by UV, and for the efficient repair of UV-induced DNA damage. These findings have established a novel role of p38γ in UV-induced DNA damage responses, and suggested that p38γ contributes to the ability of cells to cope with UV exposure by regulating the checkpoint signaling pathways and the repair of damaged DNA.

  7. Human Cardiac Tissue Engineering: From Pluripotent Stem Cells to Heart Repair

    Science.gov (United States)

    Jackman, Christopher P.; Shadrin, Ilya Y.; Carlson, Aaron L.; Bursac, Nenad

    2014-01-01

    Engineered cardiac tissues hold great promise for use in drug and toxicology screening, in vitro studies of human physiology and disease, and as transplantable tissue grafts for myocardial repair. In this review, we discuss recent progress in cell-based therapy and functional tissue engineering using pluripotent stem cell-derived cardiomyocytes and we describe methods for delivery of cells into the injured heart. While significant hurdles remain, notable advances have been made in the methods to derive large numbers of pure human cardiomyocytes, mature their phenotype, and produce and implant functional cardiac tissues, bringing the field a step closer to widespread in vitro and in vivo applications. PMID:25599018

  8. Rapid Repair of Earthquake Damaged RC Interior Beam-wide Column Joints and Beam-wall Joints Using FRP Composites

    Institute of Scientific and Technical Information of China (English)

    LI Bing; LIM Chee Leong

    2009-01-01

    This paper studies the seismic performance of FRP-strengthened RC interior non-seismically detailed beam-wide columns and beam-wall joints after limited seismic damage. Four eccentric and concentric beam-wide column joints and two beam-wall joints, initially damaged in a previous study, were repaired and tested under constant axial loads (0. \\fc'Ag and 0. 35 fc'Ag ) and lateral cyclic loading. The rapid repair technique developed, aimed to restore the original strength and to provide minimum drift capacity. The repair schemes were characterized by the use of; (a) epoxy injections and polymer modified cementitious mortar to seal the cracks and replace spalled concrete; and (b) glass (GFRP) and carbon (CFRP) sheets to enhance the joint performance. The FRP sheets were effectively prevented against possible debonding through the use of fiber anchors. Comparison between responses of specimens before and after repair clearly indicated reasonable restoration in strength, drift capacity, stiffness and cumulative energy dissipation capacity. All specimens failed with delamination of FRP sheets at beam-column joint interfaces. The rapid repair technique developed in this study is recommended for mass upgrading or repair of earthquake damaged beam-column joints.

  9. Lung tissue flap repairs esophagus defection with an inner chitosan tube stent

    Institute of Scientific and Technical Information of China (English)

    Gang Chen; Wen-Jun Shi

    2009-01-01

    AIM:To repair the partial esophagus defect with a chitosan stent, a new esophageal prosthesis made of pulmonary tissue with vascular pedicle. METHODS:Fifteen Japanese big ear white rabbits were divided into experimental group ( n = 10) and control group ( n = 5). Esophagus defect in rabbits of experimental group was repaired using lung tissue flap with a chitosan tube stent, gross and histological appearance was observed at week 2, 4 and 8 after operation, and barium sulphate X-ray screen was performed at week 10 after operation. Esophagus defect of rabbits in control group was repaired using lung tissue flap with no chitosan tube stent, gross and histological appearance was observed at week 2, 4 and 8 after operation, and barium sulphate X-ray screen was performed at week 10 after operation. RESULTS:In the experimental group, 6 rabbits survived for over two weeks, the lung tissue flap healed esophageal defec t ion, and squamous metaplasia occurred on the surface of lung tissue flap. At week 10 after operation, barium sulphate examination found that barium was fluent through the esophagus with no stricture or back stream, the creeping was good. In the control group, 4 rabbits survived for two weeks, the lung tissue flap healed esophageal defection with fibrous tissue hyperplasia, barium sulphate examination found that barium was fluent through the esophagus with a slight stricture or back stream, and the creeping was not good at week 10 after operation.CONCLUSION:Esophagus defect can be repaired using lung tissue flap with an inner chitosan tube stent.

  10. Do biomechanical properties of anterior vaginal wall prolapse tissue predict outcome of surgical repair?

    Science.gov (United States)

    Gilchrist, Alienor S; Gupta, Amit; Eberhart, Robert C; Zimmern, Philippe E

    2010-03-01

    We determined the relevance of the biomechanical properties of freshly harvested vaginal tissue during large cystocele repair on clinical outcome at a minimum 1-year followup. With institutional review board approval we prospectively studied the biomechanical properties of full thickness vaginal wall tissue from postmenopausal women with symptomatic Baden-Walker prolapse undergoing anterior vaginal wall suspension with cystocele repair from 2002 to 2005. A standardized biomechanical protocol was applied with stress-strain curves for Young's modulus obtained by blinded investigators. Failed repair was defined as recurrence on examination or reoperation for recurrent anterior prolapse. A total of 32 patients (median age 72 years) had a median followup of 34 months (range 12 to 62). Median Young's modulus was statistically different in tissue samples transported in immersed vs moistened media (median 3.8 vs 7.6, p = 0.008). Associations between Young's modulus and clinical variables were described. On followup 7 patients experienced failure of the repair. After controlling for tissue transport protocol no association was seen between Young's modulus and failures (HR 1.1, p = 0.34). This study found no association between Young's modulus and clinical results at long-term followup. This finding suggests that retropubic scarring and pelvic floor muscle properties may be more important for a successful reparative outcome than the intrinsic properties of the vaginal wall. 2010 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

  11. Customized Fabrication of Osteochondral Tissue for Articular Joint Surface Repair

    Science.gov (United States)

    2016-09-01

    Scaffolds for Cartilage Tissue Engineering. Frontiers in Bioengineering and Biotechnology . Nothing to Report Other publications, conference papers...between 20% vs. 25% and 30%. Histological analysis of ECM production using Safranin O/fast green and Alcian Blue /fast red staining is shown in...encapsulated constructs visualized by Alcian blue /fast green staining at day 28. (A-C) Staining of PDLLA-PEG 4000 group. Staining decreases as

  12. Customized Fabrication of Osteochondral Tissue for Articular Joint Surface Repair

    Science.gov (United States)

    2015-09-01

    company; or  adoption of new practices. What was the impact on society beyond science and technology ? If there is nothing significant to report during...ORGANIZATION REPORT NUMBER University of Pittsburgh, 450 Technology Drive, Pittsburgh, PA, 15219 9. SPONSORING / MONITORING AGENCY NAME(S) AND...it is a disease of the cartilage, bone and surrounding soft tissue that disables 9-10% of the US population. In the US military, combat and non

  13. Evaluation of native hyaline cartilage and repair tissue after two cartilage repair surgery techniques with 23Na MR imaging at 7 T: initial experience.

    Science.gov (United States)

    Zbýň, S; Stelzeneder, D; Welsch, G H; Negrin, L L; Juras, V; Mayerhoefer, M E; Szomolanyi, P; Bogner, W; Domayer, S E; Weber, M; Trattnig, S

    2012-08-01

    To compare the sodium normalized mean signal intensity (NMSI) values between patients after bone marrow stimulation (BMS) and matrix-associated autologous chondrocyte transplantation (MACT) cartilage repair procedures. Nine BMS and nine MACT patients were included. Each BMS patient was matched with one MACT patient according to age [BMS 36.7 ± 10.7 (mean ± standard deviation) years; MACT 36.9 ± 10.0 years], postoperative interval (BMS 33.5 ± 25.3 months; MACT 33.2 ± 25.7 months), and defect location. All magnetic resonance imaging (MRI) measurements were performed on a 7 T system. Proton images served for morphological evaluation of repair tissue using the magnetic resonance observation of cartilage repair tissue (MOCART) scoring system. Sodium NMSI values in the repair area and morphologically normal cartilage were calculated. Clinical outcome was assessed right after MRI. Analysis of covariance, t-tests, and Pearson correlation coefficients were evaluated. Sodium NMSI was significantly lower in BMS (P = 0.004) and MACT (P = 0.006) repair tissue, compared to reference cartilage. Sodium NMSI was not different between the reference cartilage in MACT and BMS patients (P = 0.664), however it was significantly higher in MACT than in BMS repair tissue (P = 0.028). Better clinical outcome was observed in BMS than in MACT patients. There was no difference between MOCART scores for MACT and BMS patients (P = 0.915). We did not observe any significant correlation between MOCART score and sodium repair tissue NMSI (r = -0.001; P = 0.996). Our results suggest higher glycosaminoglycan (GAG) content, and therefore, repair tissue of better quality in MACT than in BMS patients. Sodium imaging might be beneficial in non-invasive evaluation of cartilage repair surgery efficacy. Copyright © 2012 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.

  14. Perspectives in radiation biophysics: From radiation track structure simulation to mechanistic models of DNA damage and repair

    Science.gov (United States)

    Nikjoo, H.; Taleei, R.; Liamsuwan, T.; Liljequist, D.; Emfietzoglou, D.

    2016-11-01

    In radiation targeted therapy and genetic risk estimation of low dose radiation protection there is a crucial need for full description of DNA damage response and repair (DDR) leading to cell death and cell mutation. We propose such a description can be arrived through realistic track-structure simulations together with mechanistic mathematical formulation of DDR and the availability of experimental data for testing the proof of principle. In this paper we review briefly first the state of the art in DNA damage and repair, and then the recent advances in the physics of track structure which represents an essential tool in radiation biophysics.

  15. Repair of ultraviolet-damaged transforming DNA in a mismatch repair-deficient strain of Haemophilus influenzae

    Energy Technology Data Exchange (ETDEWEB)

    Bagci, H.; Stuy, J.H. (Florida State Univ., Tallahassee (USA). Dept. of Biological Science)

    1982-03-01

    Ultraviolet inactivation of Haemophilus influenzae transforming DNA followed inverse square root kinetics in both mismatch repair-proficient (hex/sup +/) and deficient (hex-1) recipients. No DNA concentration effect was seen with UV-excision repair-deficient (uvr/sup -/) strains. Low-efficiency genetic markers remained more sensitive than high-efficiency ones when they were assayed on excision repair-deficient hex/sup +/ uvr/sup -/ strains. They were equally resistant when hex/sup -/ uvr/sup -/ recipients were used. This was explained by assuming that recombinational repair of UV lesions in the donor strand and mismatch repair of the recipient strand may overlap and cause double strand interruptions. This will eliminate low-efficiency transformants.

  16. Alpha-phellandrene-induced DNA damage and affect DNA repair protein expression in WEHI-3 murine leukemia cells in vitro.

    Science.gov (United States)

    Lin, Jen-Jyh; Wu, Chih-Chung; Hsu, Shu-Chun; Weng, Shu-Wen; Ma, Yi-Shih; Huang, Yi-Ping; Lin, Jaung-Geng; Chung, Jing-Gung

    2015-11-01

    Although there are few reports regarding α-phellandrene (α-PA), a natural compound from Schinus molle L. essential oil, there is no report to show that α-PA induced DNA damage and affected DNA repair associated protein expression. Herein, we investigated the effects of α-PA on DNA damage and repair associated protein expression in murine leukemia cells. Flow cytometric assay was used to measure the effects of α-PA on total cell viability and the results indicated that α-PA induced cell death. Comet assay and 4,6-diamidino-2-phenylindole dihydrochloride staining were used for measuring DNA damage and condensation, respectively, and the results indicated that α-PA induced DNA damage and condensation in a concentration-dependent manner. DNA gel electrophoresis was used to examine the DNA damage and the results showed that α-PA induced DNA damage in WEHI-3 cells. Western blotting assay was used to measure the changes of DNA damage and repair associated protein expression and the results indicated that α-PA increased p-p53, p-H2A.X, 14-3-3-σ, and MDC1 protein expression but inhibited the protein of p53, MGMT, DNA-PK, and BRCA-1.

  17. Bisdemethoxycurcumin induces DNA damage and inhibits DNA repair associated protein expressions in NCI-H460 human lung cancer cells.

    Science.gov (United States)

    Yu, Chien-Chih; Yang, Su-Tso; Huang, Wen-Wen; Peng, Shu-Fen; Huang, An-Cheng; Tang, Nou-Ying; Liu, Hsin-Chung; Yang, Mei-Due; Lai, Kuang-Chi; Chung, Jing-Gung

    2016-12-01

    Nonsmall cell lung carcinoma (NSCLC) is a devastating primary lung tumor resistant to conventional therapies. Bisdemethoxycurcumin (BDMC) is one of curcumin derivate from Turmeric and has been shown to induce NSCLC cell death. Although there is one report to show BDMC induced DNA double strand breaks, however, no available information to show BDMC induced DNA damage action with inhibited DNA repair protein in lung cancer cells in detail. In this study, we tested BDMC-induced DNA damage and condensation in NCI-H460 cells by using Comet assay and DAPI staining examinations, respectively and we found BDMC induced DNA damage and condension. Western blotting was used to examine the effects of BDMC on protein expression associated with DNA damage and repair and results indicated that BDMC suppressed the protein levels associated with DNA damage and repair, such as 14-3-3σ (an important checkpoint keeper of DDR), O6-methylguanine-DNA methyltransferase, DNA repair proteins breast cancer 1, early onset, mediator of DNA damage checkpoint 1 but activate phosphorylated p53 and p-H2A.X (phospho Ser140) in NCI-H460 cells. Confocal laser systems microscopy was used for examining the protein translocation and results show that BDMC increased the translocation of p-p53 and p-H2A.X (phospho Ser140) from cytosol to nuclei in NCI-H460 cells. In conclusion, BDMC induced DNA damage and condension and affect DNA repair proteins in NCI-H460 cells in vitro. © 2015 Wiley Periodicals, Inc. Environ Toxicol 31: 1859-1868, 2016. © 2015 Wiley Periodicals, Inc.

  18. Bioinspired Nanoparticulate Medical Glues for Minimally Invasive Tissue Repair.

    Science.gov (United States)

    Lee, Yuhan; Xu, Chenjie; Sebastin, Monisha; Lee, Albert; Holwell, Nathan; Xu, Calvin; Miranda Nieves, David; Mu, Luye; Langer, Robert S; Lin, Charles; Karp, Jeffrey M

    2015-11-18

    Delivery of tissue glues through small-bore needles or trocars is critical for sealing holes, affixing medical devices, or attaching tissues together during minimally invasive surgeries. Inspired by the granule-packaged glue delivery system of sandcastle worms, a nanoparticulate formulation of a viscous hydrophobic light-activated adhesive based on poly(glycerol sebacate)-acrylate is developed. Negatively charged alginate is used to stabilize the nanoparticulate surface to significantly reduce its viscosity and to maximize injectability through small-bore needles. The nanoparticulate glues can be concentrated to ≈30 w/v% dispersions in water that remain localized following injection. With the trigger of a positively charged polymer (e.g., protamine), the nanoparticulate glues can quickly assemble into a viscous glue that exhibits rheological, mechanical, and adhesive properties resembling the native poly(glycerol sebacate)-acrylate based glues. This platform should be useful to enable the delivery of viscous glues to augment or replace sutures and staples during minimally invasive procedures.

  19. Direct detection and quantification of abasic sites for in vivo studies of DNA damage and repair

    Energy Technology Data Exchange (ETDEWEB)

    Wang Yanming [Division of Radiopharmaceutical Science, Case Center for Imaging Research, Department of Radiology, Case Western Reserve University, Cleveland, OH 44122 (United States)], E-mail: yanming.wang@case.edu; Liu Lili [Department of Hematology and Oncology, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44122 (United States); Wu Chunying [Division of Radiopharmaceutical Science, Case Center for Imaging Research, Department of Radiology, Case Western Reserve University, Cleveland, OH 44122 (United States); Bulgar, Alina [Department of Hematology and Oncology, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44122 (United States); Somoza, Eduardo; Zhu Wenxia [Division of Radiopharmaceutical Science, Case Center for Imaging Research, Department of Radiology, Case Western Reserve University, Cleveland, OH 44122 (United States); Gerson, Stanton L. [Department of Hematology and Oncology, Case Comprehensive Cancer Center, Case Western Reserve University, Cleveland, OH 44122 (United States)

    2009-11-15

    Use of chemotherapeutic agents to induce cytotoxic DNA damage and programmed cell death is a key strategy in cancer treatments. However, the efficacy of DNA-targeted agents such as temozolomide is often compromised by intrinsic cellular responses such as DNA base excision repair (BER). Previous studies have shown that BER pathway resulted in formation of abasic or apurinic/apyrimidinic (AP) sites, and blockage of AP sites led to a significant enhancement of drug sensitivity due to reduction of DNA base excision repair. Since a number of chemotherapeutic agents also induce formation of AP sites, monitoring of these sites as a clinical correlate of drug effect will provide a useful tool in the development of DNA-targeted chemotherapies aimed at blocking abasic sites from repair. Here we report an imaging technique based on positron emission tomography (PET) that allows for direct quantification of AP sites in vivo. For this purpose, positron-emitting carbon-11 has been incorporated into methoxyamine ([{sup 11}C]MX) that binds covalently to AP sites with high specificity. The binding specificity of [{sup 11}C]MX for AP sites was demonstrated by in vivo blocking experiments. Using [{sup 11}C]MX as a radiotracer, animal PET studies have been conducted in melanoma and glioma xenografts for quantification of AP sites. Following induction of AP sites by temozolomide, both tumor models showed significant increase of [{sup 11}C]MX uptake in tumor regions in terms of radioactivity concentration as a function of time, which correlates well with conventional aldehyde reactive probe (ARP)-based bioassays for AP sites.

  20. Telocytes as a Source of Progenitor Cells in Regeneration and Repair Through Granulation Tissue.

    Science.gov (United States)

    Díaz-Flores, Lucio; Gutiérrez, Ricardo; Pino García, Maria; González, Miriam; Díaz-Flores, Lucio; Francisco Madrid, Juan

    2016-01-01

    This review outlines the role of CD34+ stromal cells/telocytes (CD34+ SC/TCs) in repair and considers the following issues. Firstly, the conceptual aspects of repair, including regeneration and repair through granulation tissue (RTGT) as two types of repair, RTGT stages (inflammatory, proliferative, and remodeling), and tissue in repair as a substrate to assess the in vivo behavior of activated CD34+ SC/TCs. Subsequently, current knowledge of CD34+ SC/TCs, such as identification, characteristics, and functions, as well as possible stages (quiescent and activated) are taken into account. We then consider the role in regeneration of quiescent CD34+ SC/TCs (in unperturbed physiological conditions) as a nurse of stem cells (e.g., in the heart, skin, respiratory tree, gastrointestinal tract, liver, eye, and choroid plexus). Special attention is paid to the characteristics of activated CD34+ SC/TCs and the overlapping steps of activation with and without loss of CD34 expression and with and without gain of αSMA expression. With this contribution, we establish the role of CD34+ SC/TCs as progenitor cells and as a source of fibroblasts and myofibroblasts in repair through granulation tissue, fibrosis, and tumor stroma. Activated CD34+ SC/TCs in encapsulation and other processes (e.g., Reinke's edema, cutaneous myxoid cyst, mixomatous mitral valve degeneration, and fibrous papula of the face) are also outlined. Finally, similarities between modifications of CD34+ SC/TCs during in vivo activation and of multipotent mesenchymal stromal/stem cells in culture are examined in order to correlate the growing literature on CD34+ SC/TCs and the exponential research in cultured mesenchymal stromal/stem cells.

  1. Assessment of Damage to Nucleic Acids and Repair Machinery in Salmonella typhimurium Exposed to Chlorine

    Directory of Open Access Journals (Sweden)

    M. H. Phe

    2009-01-01

    Full Text Available Water disinfection is usually evaluated using mandatory methods based on cell culturability. However, such methods do not consider the potential of cells to recover, which should also be kept as low as possible. In this paper, we hypothesized that a successful disinfection is achieved only when the applied chlorine leads to both intracellular nucleic acid damage and strong alterations of the DNA repair machinery. Monitoring the SOS system responsiveness with a umuC'-‘lacZ reporter fusion, we found that the expression of this important cellular machinery was altered after the beginning of membrane permeabilization but prior to the total decline of both the cell culturability and the nucleic acid integrity as revealed by Sybr-II staining. Rapid measurement of such nucleic acid alterations by fluorochrome-based staining could be used as an alternative method for assessing the effectiveness of disinfection with chlorine.

  2. Repair of ultraviolet light-induced DNA damage in cholera bacteriophages

    Energy Technology Data Exchange (ETDEWEB)

    Palit, B.N.; Das, G.; Das, J. (Indian Inst. of Chemical Biology, Calcutta. Dept. of Biophysics)

    1983-08-01

    DNA repair-proficient and -deficient strains of Vibrio cholerae were used to examine host cell reactivation, Weigle reactivation and photoreactivation of u.v.-irradiated cholera bacteriophages. U.v. light-induced DNA damage in phages of different morphological and serological groups could be efficiently photoreactivated. Host cell reactivation of irradiated phages of different groups was different on the same indicator host. Phage phi149 was the most sensitive, and phi138 the most resistant to u.v. irradiation. While phi138 showed appreciable host cell reactivation, this was minimal for phi149. Attempts to demonstrate Weigle reactivation of u.v.-irradiated cholera phages were not successful, although u.v.-induced filamentation of host cells was observed.

  3. Tai chi improves oxidative stress response and DNA damage/repair in young sedentary females.

    Science.gov (United States)

    Huang, Xing-Yu; Eungpinichpong, Wichai; Silsirivanit, Atit; Nakmareong, Saowanee; Wu, Xiu-Hua

    2014-06-01

    [Purpose] This study was to examine the effects of 12 weeks of Tai Chi (TC) exercise on antioxidant capacity, and DNA damage/repair in young females who did not perform regular physical exercise. [Subjects and Methods] Ten female students from a Chinese university voluntarily participated in this program. All of them practiced the 24-form simplified Tai Chi, 5 times weekly, for 12 weeks. Plasma levels of superoxide dismutase (SOD), glutathione peroxidase (GPx), malondialdehyde (MDA), glutathione (GSH), hydroxyl radical inhibiting capacity (OH·-IC), 8-hydroxy-2'-deoxyguanosine (8-OHdG), and 8-oxoguanine DNA glycosylase (OGG1) were measured at 0, 8, and 12 weeks. Heart rate (HR) was monitored during the last set of the training session at 4, 8, and 12 weeks. [Results] Plasma SOD and OH·-IC levels were increased at 8 and 12 weeks compared to the baseline (0 weeks). Gpx and GSH levels did not change significantly throughout the study period. The plasma MDA level was decreased significantly at 8 weeks but not at 12 weeks compared to the baseline value. While the plasma 8-OHdG level did not change throughout the study period, the plasma OGG1 level was significantly increased at 8 and 12 weeks compared to the baseline value. [Conclusion] TC practice for 12 weeks efficiently improved the oxidative stress response in young females who did not perform regular physical exercise. The TC exercise also increased the DNA repairing capacity.

  4. RadA: A protein involved in DNA damage repair processes of Deinococcus radiodurans R1

    Institute of Scientific and Technical Information of China (English)

    ZHOU Qing; ZHANG Xinjue; XU Hong; XU Bujin; HUA Yuejin

    2006-01-01

    RadA is highly conserved in bacteria and belongs to the RecA/RadA/Rad51 protein superfamily found in bacteria, archaea and eukarya. In Archaea, it plays a critical role in homologous recombination process due to its RecA-like function. In Escherichia coli, it takes part in conjugational recombination and DNA repair but is not as important as that of archaea. Using PSI-BLAST searches, we found that Deinococcus radiodurans RadA had a higher similarity to that of bacteria than archaea and eukarya. Disruption of radA gene in D. radiodurans resulted in a modestly decreased resistance to gamma radiation and ultraviolet, but had no effect on the resistance to hydrogen peroxide. Complementation of the radA disruptant by both E. coli radA and D.radiodurans radA could fully restore its resistance to gamma radiation and ultraviolet irradiation. Further domain function analyses of D. radiodurans RadA showed that the absence of the zinc finger domain resulted in a slightly more sensitive phenotype togamma and UV radiation than that of the radA mutant,while the absence of the Lon protease domain exhibited a slightly increased resistance to gamma and UV radiation. These data suggest that D. radiodurans RadA does play an important role in the DNA damage repair processes and its three different domains have different functions.

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

    Science.gov (United States)

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

    2011-09-01

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

  6. Harnessing neural activity to promote repair of the damaged corticospinal system after spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    John H. Martin

    2016-01-01

    As most spinal cord injuries (SCIs) are incomplete, an important target for promoting neural repair and recovery of lost motor function is to promote the connections of spared descending spinal pathways with spinal motor circuits. Among the pathways, the corticospinal tract (CST) is most associated with skilled voluntary functions in humans and many animals. CST loss, whether at its origin in the motor cortex or in the white matter tracts subcortically and in the spinal cord, leads to movement impairments and paraly-sis. To restore motor function after injury will require repair of the damaged CST. In this review, I discuss how knowledge of activity-dependent development of the CST—which establishes connectional speci-ifcity through axon pruning, axon outgrowth, and synaptic competition among CST terminals—informed a novel activity-based therapy for promoting sprouting of spared CST axons after injur in mature animals. This therapy, which comprises motor cortex electrical stimulation with and without concurrent trans-spi-nal direct current stimulation, leads to an increase in the gray matter axon length of spared CST axons in the rat spinal cord and, after a pyramidal tract lesion, restoration of skilled locomotor movements. I discuss how this approach is now being applied to a C4 contusion rat model.

  7. Harnessing neural activity to promote repair of the damaged corticospinal system after spinal cord injury

    Directory of Open Access Journals (Sweden)

    John H Martin

    2016-01-01

    Full Text Available As most spinal cord injuries (SCIs are incomplete, an important target for promoting neural repair and recovery of lost motor function is to promote the connections of spared descending spinal pathways with spinal motor circuits. Among the pathways, the corticospinal tract (CST is most associated with skilled voluntary functions in humans and many animals. CST loss, whether at its origin in the motor cortex or in the white matter tracts subcortically and in the spinal cord, leads to movement impairments and paralysis. To restore motor function after injury will require repair of the damaged CST. In this review, I discuss how knowledge of activity-dependent development of the CST-which establishes connectional specificity through axon pruning, axon outgrowth, and synaptic competition among CST terminals-informed a novel activity-based therapy for promoting sprouting of spared CST axons after injur in mature animals. This therapy, which comprises motor cortex electrical stimulation with and without concurrent trans-spinal direct current stimulation, leads to an increase in the gray matter axon length of spared CST axons in the rat spinal cord and, after a pyramidal tract lesion, restoration of skilled locomotor movements. I discuss how this approach is now being applied to a C 4 contusion rat model.

  8. Assessment by Southern blot analysis of UV-induced damage and repair in human immunoglobulin genes.

    Science.gov (United States)

    Bianchi, M S; Bianchi, N O; de la Chapelle, A

    1990-09-01

    Irradiation of DNA with UV light induces pyrimidine dimers and (6-4) photoproducts. The presence of one of these photolesions in the restriction site of a given endonuclease inhibits DNA cleavage and induces the formation of fragments by incomplete DNA digestion which appear as additional, facultative bands in Southern hybridization autoradiograms. The number and size of these fragments show a positive correlation with the UV dose. The response to UV light of immunoglobulin light-chain constant kappa and heavy-chain constant mu genes was analyzed with 2 specific probes. Constant kappa and mu genes when irradiated as part of the chromatin of living lymphocytes showed a UV sensitivity similar to that of naked DNA. The same genes from granulocytes had 50-60 times lower UV sensitivity. When cells were allowed to repair photolesions for 24 h the facultative bands from granulocytes disappeared indicating that these cells were able to remove photolesions from constant kappa and mu genes. Facultative bands from lymphocytes showed a smaller decrease of density after 24 h repair. This suggests that lymphocytes are less efficient than granulocytes in removing UV damage from constant kappa and mu genes.

  9. The Fanconi anemia pathway: Repairing the link between DNA damage and squamous cell carcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Romick-Rosendale, Lindsey E. [Division of Oncology, Cancer and Blood Diseases Institute, Cincinnati Children' s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229 (United States); Lui, Vivian W.Y.; Grandis, Jennifer R. [Department of Otolaryngology, University of Pittsburgh School of Medicine, University of Pittsburgh, Pittsburgh, PA 15213 (United States); Wells, Susanne I., E-mail: Susanne.Wells@cchmc.org [Division of Oncology, Cancer and Blood Diseases Institute, Cincinnati Children' s Hospital Medical Center, Department of Pediatrics, University of Cincinnati College of Medicine, Cincinnati, OH 45229 (United States)

    2013-03-15

    Fanconi anemia (FA) is a rare inherited recessive disease caused by mutations in one of fifteen genes known to encode FA pathway components. In response to DNA damage, nuclear FA proteins associate into high molecular weight complexes through a cascade of post-translational modifications and physical interactions, followed by the repair of damaged DNA. Hematopoietic cells are particularly sensitive to the loss of these interactions, and bone marrow failure occurs almost universally in FA patients. FA as a disease is further characterized by cancer susceptibility, which highlights the importance of the FA pathway in tumor suppression, and will be the focus of this review. Acute myeloid leukemia is the most common cancer type, often subsequent to bone marrow failure. However, FA patients are also at an extreme risk of squamous cell carcinoma (SCC) of the head and neck and gynecological tract, with an even greater incidence in those individuals who have received a bone marrow transplant and recovered from hematopoietic disease. FA tumor suppression in hematopoietic versus epithelial compartments could be mechanistically similar or distinct. Definition of compartment specific FA activities is now critical to assess the effects of today's bone marrow failure treatments on tomorrow's solid tumor development. It is our hope that current therapies can then be optimized to decrease the risk of malignant transformation in both hematopoietic and epithelial cells. Here we review our current understanding of the mechanisms of action of the Fanconi anemia pathway as it contributes to stress responses, DNA repair and squamous cell carcinoma susceptibility.

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

    Directory of Open Access Journals (Sweden)

    Xie L

    2016-11-01

    Full Text Available Lisha Xie,1,* Tiancen Zhao,1,2,* Jing Cai,1 You Su,1 Zehua Wang,1 Weihong Dong1 1Department of Obstetrics and Gynecology, Union Hospital, Tongji Medical College, Huazhong University of Science and Technology, 2Department of Obstetrics and Gynecology, Central Hospital of Wuhan, Wuhan, China *These authors contributed equally to this work Objective: The objective of this study was to investigate the mechanism of sensitivity to methotrexate (MTX in human choriocarcinoma cells regarding DNA damage response. Methods: Two choriocarcinoma cancer cell lines, JAR and JEG-3, were utilized in this study. An MTX-sensitive osteosarcoma cell line MG63, an MTX-resistant epithelial ovarian cancer cell line A2780 and an MTX-resistant cervical adenocarcinoma cell line Hela served as controls. Cell viability assay was carried out to assess MTX sensitivity of cell lines. MTX-induced DNA damage was evaluated by comet assay. Quantitative reverse transcription polymerase chain reaction was used to detect the mRNA levels of BRCA1, BRCA2, RAD51 and RAD52. The protein levels of γH2AX, RAD 51 and p53 were analyzed by Western blot. Results: Remarkable DNA strand breaks were observed in MTX-sensitive cell lines (JAR, JEG-3 and MG63 but not in MTX-resistant cancer cells (A2780 and Hela after 48 h of MTX treatment. Only in the choriocarcinoma cells, the expression of homologous recombination (HR repair gene RAD51 was dramatically suppressed by MTX in a dose- and time-dependent manner, accompanied with the increase in p53. Conclusion: The MTX-induced DNA strand breaks accompanied by deficiencies in HR repair may contribute to the hypersensitivity to chemotherapy in choriocarcinoma. Keywords: choriocarcinoma, chemotherapy hypersensitivity, DNA double-strand break, RAD51, p53

  11. ShaPINg cell fate upon DNA damage:role of Pin1 isomerase in DNA damage-induced cell death and repair

    Directory of Open Access Journals (Sweden)

    Thomas G Hofmann

    2014-06-01

    Full Text Available The peptidyl-prolyl cis/trans isomerase Pin1 acts as a molecular timer in proline-directed Ser/Thr kinase signaling and shapes cellular responses based on recognition of phosphorylation marks and implementing conformational changes in its substrates. Accordingly, Pin1 has been linked to numerous phosphorylation-controlled signaling pathways and cellular processes such as cell cycle progression, proliferation and differentiation. In addition, Pin1 plays a pivotal role in DNA damage-triggered cell fate decisions. Whereas moderate DNA damage is balanced by DNA repair, cells confronted with massive genotoxic stress are eliminated by the induction of programmed cell death or cellular senescence. In this review we summarize and discuss the current knowledge on how Pin1 specifies cell fate through regulating key players of the apoptotic and the repair branch of the DNA damage response.

  12. Hypothermia postpones DNA damage repair in irradiated cells and protects against cell killing

    Energy Technology Data Exchange (ETDEWEB)

    Baird, Brandon J.; Dickey, Jennifer S.; Nakamura, Asako J.; Redon, Christophe E.; Parekh, Palak [Laboratory of Molecular Pharmacology, CCR, NCI, Bethesda, MD 20892 (United States); Griko, Yuri V. [Radiation and Space Biotechnology Branch, NASA Ames Research Center, Moffett Field, CA 94035 (United States); Aziz, Khaled; Georgakilas, Alexandros G. [Biology Department, East Carolina University, Greenville, NC 27858 (United States); Bonner, William M. [Laboratory of Molecular Pharmacology, CCR, NCI, Bethesda, MD 20892 (United States); Martin, Olga A., E-mail: sedelnio@mail.nih.gov [Laboratory of Molecular Pharmacology, CCR, NCI, Bethesda, MD 20892 (United States)

    2011-06-03

    Hibernation is an established strategy used by some homeothermic organisms to survive cold environments. In true hibernation, the core body temperature of an animal may drop to below 0 {sup o}C and metabolic activity almost cease. The phenomenon of hibernation in humans is receiving renewed interest since several cases of victims exhibiting core body temperatures as low as 13.7 {sup o}C have been revived with minimal lasting deficits. In addition, local cooling during radiotherapy has resulted in normal tissue protection. The experiments described in this paper were prompted by the results of a very limited pilot study, which showed a suppressed DNA repair response of mouse lymphocytes collected from animals subjected to 7-Gy total body irradiation under hypothermic (13 {sup o}C) conditions, compared to normothermic controls. Here we report that human BJ-hTERT cells exhibited a pronounced radioprotective effect on clonogenic survival when cooled to 13 {sup o}C during and 12 h after irradiation. Mild hypothermia at 20 and 30 {sup o}C also resulted in some radioprotection. The neutral comet assay revealed an apparent lack on double strand break (DSB) rejoining at 13 {sup o}C. Extension of the mouse lymphocyte study to ex vivo-irradiated human lymphocytes confirmed lower levels of induced phosphorylated H2AX ({gamma}-H2AX) and persistence of the lesions at hypothermia compared to the normal temperature. Parallel studies of radiation-induced oxidatively clustered DNA lesions (OCDLs) revealed partial repair at 13 {sup o}C compared to the rapid repair at 37 {sup o}C. For both {gamma}-H2AX foci and OCDLs, the return of lymphocytes to 37 {sup o}C resulted in the resumption of normal repair kinetics. These results, as well as observations made by others and reviewed in this study, have implications for understanding the radiobiology and protective mechanisms underlying hypothermia and potential opportunities for exploitation in terms of protecting normal tissues against

  13. Chinese green tea consumption reduces oxidative stress, inflammation and tissues damage in smoke exposed rats

    Directory of Open Access Journals (Sweden)

    Wajdy Al-Awaida

    2014-10-01

    Conclusion: Exposure of albino rat model to cigarette smoke caused oxidative stress, altered the cellular antioxidant defense system, induced apoptosis in lung tissue, inflammation and tissues damage, which could be prevented by supplementation of CGT.

  14. A cell-free system for studying a priming factor involved in repair of bleomycin-damaged DNA.

    Directory of Open Access Journals (Sweden)

    Seki,Shuji

    1989-04-01

    Full Text Available A simple cell-free system for studying a priming factor involved in the repair of bleomycin-damaged DNA was established. The template-primer used for the repair DNA synthesis was prepared by treating the closed circular, superhelical form of pUC19 plasmid DNA with 2.2 microM bleomycin and 20 microM ferrous ions. Single-strand breaks were introduced into pUC19 DNA by the bleomycin treatment, and the DNA was consequently converted largely into the open circular form. A system for repair of this bleomycin-damaged DNA was constructed with a priming factor, DNA polymerase (DNA polymerase beta or Klenow fragment of DNA polymerase I, ATP, T4 DNA ligase and four deoxynucleoside triphosphates. After incubation, the conformation of the DNA was analyzed by agarose gel electrophoresis and electron microscopy. The open circular DNA was largely converted to the closed circular DNA, indicating that the single-strand breaks of DNA were repaired. When the priming factor was omitted, DNA repair did not occur. The present system seemed to be applicable to the study of priming factors involved in the repair of DNA with single-strand breaks caused not only by bleomycin but also by ionizing radiation or active oxygen.

  15. Association Between Polymorphisms of DNA Repair Gene XRCC1 and DNA Damage in Asbestos-Exposed Workers

    Institute of Scientific and Technical Information of China (English)

    XIAO-HONG ZHAO; GUANG JIA; YONG-QUAN LIU; SHAO-WEI LIU; LEI YAN; YU JIN; NIAN LIU

    2006-01-01

    Objective To compare the asbestos-induced DNA damage and repair capacities of DNA damage between 104 asbestos exposed workers and 101 control workers in Qingdao City of China and to investigate the possible association between polymorphisms in codon 399 of XRCC1 and susceptibility to asbestosis. Methods DNA damage levels in peripheral bloodlymphocytes were determined by comet assay, and XRCC 1 genetic polymorphisms of DNA samples from 51 asbestosis cases and 53 non-asbestosis workers with a similar asbestos exposure history were analyzed by PCR/RFLP. Results The basal comet scores (3.95±2.95) were significantly higher in asbestos-exposed workers than in control workers (0.10±0.28). After 1 h H2O2 stimulation, DNA damage of lymphocytes exhibited different increases. After a 4 h repair period, the comet scores were 50.98±19.53 in asbestos-exposed workers and 18.32±12.04 in controls. The residual DNA damage (RD) was significantly greater (P<0.01) in asbestos-exposed workers (35.62%) than in controls (27.75%). XRCC1 genetic polymorphism in 104 asbestos-exposed workers was not associated with increased risk of asbestosis. But compared with polymorphisms in the DNA repair gene XRCC1 (polymorphisms in codon 399) and the DNA damage induced by asbestos, the comet scores in asbestosis cases with Gln/Gln, Gln/Arg, and Arg/Arg were 40.26±18.94, 38.03±28.22, and 32.01±11.65, respectively, which were higher than those in non-asbestosis workers with the same genotypes (25.58±11.08, 37.08±14.74, and 29.38±10.15). There were significant differences in the comet scores between asbestosis cases and non-asbestosis workers with Gln/Gln by Student's t-test (P<0.05 or 0.01). The comet scores were higher in asbestosis workers with Gln/Gln than in those with Arg/Arg and in non-asbestosis workers exposed to asbestos, but without statistically significant difference. Conclusions Exposure to asbestos may be related to DNA damage or the capacity of cells to repair H2O2-induced

  16. Assessment of the repair and damage of DNA induced by parent and reduced RSU-1069, a 2-nitroimidazole-aziridine

    Energy Technology Data Exchange (ETDEWEB)

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

    1989-04-01

    The cellular repair and damage of DNA induced by parent and reduced RSU-1069, a 2-nitroimidazole-aziridine, was assessed at both the molecular and cellular level. At the molecular level, after in vitro incubation with parent or reduced RSU-1069, plasmid DNA was transfected into Escherichia coli (AB1157) with subsequent selection for gene expression. For equivalent levels of DNA strand breakage following such treatment it is evident from the relative transformation frequencies that interactions with reduced RSU-1069 lead to DNA damage consistent with bifunctional action of a metabolite(s). At the cellular level, the cytoxicity of RSU-1069 was determined for a series of repair deficient mutants of E. coli under both aerobic and hypoxic conditions. The differential aerobic:hypoxic cytotoxicity ratio is approximately 3. We conclude that the repair of cellular DNA damage induced by RSU-1069 involves activation of the gene products under the control of the recA gene and not those under the control of the ada gene. The ability of cellular systems to repair damage induced by RSU-1069 may play a significant role in determining its efficiency to act as a hypoxic cell radiosensitizer and a hypoxia selective cytotoxin.

  17. In situ repair of vagus nerve stimulator lead damage: technical note.

    Science.gov (United States)

    Ralston, Ashley; Ogden, Patti; Kohrman, Michael H; Frim, David M

    2016-12-01

    Vagus nerve stimulators (VNSs) are currently an accepted treatment for intractable epilepsy not amenable to ablative surgery. Battery death and lead damage are the main reasons for reoperation in patients with VNSs. In general, any damage to the lead requires revision surgery to remove the helical electrodes from the vagus nerve and replace the electrode array and wire. The electrodes are typically scarred and difficult to remove from the vagus nerve without injury. The authors describe 6 patients with VNSs who presented with low lead impedance on diagnostic testing, leading to the intraoperative finding of lead insulation disruption, or who were found incidentally at the time of implantable pulse generator battery replacement to have a tear in the outer insulation of the electrode wire. Instead of replacement, the wire insulation was repaired and reinforced in situ, leading to normal impedance testing. All 6 devices remained functional over a follow-up period of up to 87 months, with 2 of the 6 patients having a relatively shorter follow-up of only 12 months. This technique, applicable in a subset of patients with VNSs requiring lead exploration, obviates the need for lead replacement with its attendant risks.

  18. Repair of dense connective tissues via biomaterial-mediated matrix reprogramming of the wound interface.

    Science.gov (United States)

    Qu, Feini; Pintauro, Michael P; Haughan, Joanne E; Henning, Elizabeth A; Esterhai, John L; Schaer, Thomas P; Mauck, Robert L; Fisher, Matthew B

    2015-01-01

    Repair of dense connective tissues in adults is limited by their intrinsic hypocellularity and is exacerbated by a dense extracellular matrix (ECM) that impedes cellular migration to and local proliferation at the wound site. Conversely, healing in fetal tissues occurs due in part to an environment conducive to cell mobility and division. Here, we investigated whether the application of a degradative enzyme, collagenase, could reprogram the adult wound margin to a more fetal-like state, and thus abrogate the biophysical impediments that hinder migration and proliferation. We tested this concept using the knee meniscus, a commonly injured structure for which few regenerative approaches exist. To focus delivery and degradation to the wound interface, we developed a system in which collagenase was stored inside poly(ethylene oxide) (PEO) electrospun nanofibers and released upon hydration. Through a series of in vitro and in vivo studies, our findings show that partial digestion of the wound interface improves repair by creating a more compliant and porous microenvironment that expedites cell migration to and/or proliferation at the wound margin. This innovative approach of targeted manipulation of the wound interface, focused on removing the naturally occurring barriers to adult tissue repair, may find widespread application in the treatment of injuries to a variety of dense connective tissues.

  19. Tissue engineering applications: cartilage lesions repair by the use of autologous chondrocytes

    Directory of Open Access Journals (Sweden)

    L. De Franceschi

    2011-09-01

    Full Text Available Promising new therapies based on tissue engineering have been recently developed for cartilage repair. The association of biomaterials with autologous chondrocytes expanded in vitro can represent a useful tool to regenerate this tissue. The scaffolds utilised in such therapeutical applications should provide a pre-formed three-dimensional shape, prevent cells from floating out of the defect, have sufficient mechanical strength, facilitate uniform spread of cells and stimulate the phenotype of transplanted cells. Hyaff®-11 is a hyaluronic-acid based biodegradable polymer, that has been shown to provide successful cell carrier for tissue-engineered repair. From our findings we can state that human chondrocytes seeded on Hyaff®-11 are able to maintain in vitro the characteristic of differentiated cells, expressing and producing collagen type II and aggrecan which are the main markers of cartilage phenotype, down-regulating collagen type I. Moreover, it seems to be a useful scaffold for cartilage repair both in animal models and clinical trials in humans, favouring the formation of a hyaline-like tissue. In the light of these data, we can hypothesise, for the future, the use of autologous chondrocyte transplantation together with gene therapy as a treatment for rheumatic diseases such as osteoarthritis.

  20. Damage and repair of the peripheral myelin sheath and node of Ranvier after treatment with trypsin.

    Science.gov (United States)

    Yu, R C; Bunge, R P

    1975-01-01

    Cultures of whole fetal rat sensory ganglia which had matured and myelinated in culture were treated for 1-3 h with a pulse of 0.2% trypsin. The tissue was observed during the period of treatment and during subsequent weeks using both light and electron microscopy. Within minutes after trypsin addition the matrix of the culture was altered and the nerve fascicles loosened. Progressive changes included the retraction of Schwann cell processes from the nodal region the detachment of the myelin-related paranodal Schwann cell loops from the axon, and lengthening of the nodal region as the axon was bared. The retraction of myelin from nodal stabilized several hours after trypsin withdrawal. Breakdown of the altered myelin segments was rare. There were no discernable changes in neurons or their processes after this exposure to trypsin. The partial repair which occured over a period of several weeks included the reattachment of paranodal Schwann cell loops to the axolemma and the insertion of new myelin segments where a substantial length of axolemma had been bared. The significance of these observations to the characterization of the Schwann cell-axolemmal junctions on myelinated nerve fibers is discussed. The dramatic degree of myelin change that can occur without concomitant myelin breakdown is particularly noted, as is the observation that these altered myelin segments are, in part, repaired.

  1. Protein expression of DNA damage repair proteins dictates response to topoisomerase and PARP inhibitors in triple-negative breast cancer.

    Directory of Open Access Journals (Sweden)

    Julie L Boerner

    Full Text Available Patients with metastatic triple-negative breast cancer (TNBC have a poor prognosis. New approaches for the treatment of TNBC are needed to improve patient survival. The concept of synthetic lethality, brought about by inactivating complementary DNA repair pathways, has been proposed as a promising therapeutic option for these tumors. The TNBC tumor type has been associated with BRCA mutations, and inhibitors of Poly (ADP-ribose polymerase (PARP, a family of proteins that facilitates DNA repair, have been shown to effectively kill BRCA defective tumors by preventing cells from repairing DNA damage, leading to a loss of cell viability and clonogenic survival. Here we present preclinical efficacy results of combining the PARP inhibitor, ABT-888, with CPT-11, a topoisomerase I inhibitor. CPT-11 binds to topoisomerase I at the replication fork, creating a bulky adduct that is recognized as damaged DNA. When DNA damage was stimulated with CPT-11, protein expression of the nucleotide excision repair enzyme ERCC1 inversely correlated with cell viability, but not clonogenic survival. However, 4 out of the 6 TNBC cells were synergistically responsive by cell viability and 5 out of the 6 TNBC cells were synergistically responsive by clonogenic survival to the combination of ABT-888 and CPT-11. In vivo, the BRCA mutant cell line MX-1 treated with CPT-11 alone demonstrated significant decreased tumor growth; this decrease was enhanced further with the addition of ABT-888. Decrease in tumor growth correlated with an increase in double strand DNA breaks as measured by γ-H2AX phosphorylation. In summary, inhibiting two arms of the DNA repair pathway simultaneously in TNBC cell lines, independent of BRCA mutation status, resulted in un-repairable DNA damage and subsequent cell death.

  2. Nd : YAG surgical laser effects in canine prostate tissue: temperature and damage distribution

    NARCIS (Netherlands)

    van Nimwegen, S. A.; L'Eplattenier, H. F.; Rem, A. I.; van der Lugt, J. J.; Kirpensteijn, J.

    2009-01-01

    An in vitro model was used to predict short-term, laser-induced, thermal damage in canine prostate tissue. Canine prostate tissue samples were equipped with thermocouple probes to measure tissue temperature at 3, 6, 9 and 12 mm depths. The tissue surface was irradiated with a Nd:YAG laser in contact

  3. Comparison of Genotoxic Damage in Monolayer Cell and Three-Dimensional Tissue-Like Cell Assemblies

    Science.gov (United States)

    Behravesh, E.; Emami, K.; Wu, H.; Gonda, S.

    Risk assessment for the biological effects of high-energy charged particles, ranging from protons to iron nuclei, encountered in space is essential for the success of long-term space exploration. While prokaryotic and eukaryotic cell models, developed in our lab and others, have advanced our understanding of many aspects of genotoxicity, there is a need for in vitro models to assess the risk to humans from space radiation insults that are representative of the cellular interactions present in tissues and capable of quantifying genotoxic damage. Toward this overall goal, the objective of this study is to examine the effect of the localized microenvironment of cells, either cultured as 2-dimensional monolayers (2D) or 3-dimensional aggregates (3D), on the rate and type of genotoxic damage, and to examine those effects after the normal cell repair processes. Rodent transgenic cell lines containing 50-70 copies of a transgene were utilized to provide the enhanced sensitivity required to enable the identification and quantification of the types of mutational events incurred from exposure to iron charged particles which makes up a significant portion of Space radiation. Although the LacI target of this system is ~1000 bps, each copy of the entire construct is over 45 kbps. The utilization of this system allows for the quantification of mutational frequency and type for the LacI target as well as assessment of DNA damage for the entire 45 kbp construct. The samples were exposed to high-LET iron charged particles at Brookhaven National Laboratory's AGS/NSRL facilities for a total dose of 0, 0.1, 0.25, 0.5, 1.0, and 2.0 Gy and recovered after 0, 1, and 7 days of tissue culture post-irradiation. The mutational frequency was found to be greater for the 3D samples when compared to the 2D samples at all doses. In addition, there was increased mutational frequency with 7 days culture post irradiation when compared to samples analyzed immediately after exposure. DNA sequencing of

  4. Nicotinamide enhances repair of ultraviolet radiation-induced DNA damage in human keratinocytes and ex vivo skin.

    Science.gov (United States)

    Surjana, Devita; Halliday, Gary M; Damian, Diona L

    2013-05-01

    Nicotinamide (vitamin B3) protects from ultraviolet (UV) radiation-induced carcinogenesis in mice and from UV-induced immunosuppression in mice and humans. Recent double-blinded randomized controlled Phase 2 studies in heavily sun-damaged individuals have shown that oral nicotinamide significantly reduces premalignant actinic keratoses, and may reduce new non-melanoma skin cancers. Nicotinamide is a precursor of nicotinamide adenine dinucleotide (NAD(+)), an essential coenzyme in adenosine triphosphate (ATP) production. Previously, we showed that nicotinamide prevents UV-induced ATP decline in HaCaT keratinocytes. Energy-dependent DNA repair is a key determinant of cellular survival after exposure to DNA-damaging agents such as UV radiation. Hence, in this study we investigated whether nicotinamide protection from cellular energy loss influences DNA repair. We treated HaCaT keratinocytes with nicotinamide and exposed them to low-dose solar-simulated UV (ssUV). Excision repair was quantified using an assay of unscheduled DNA synthesis. Nicotinamide increased both the proportion of cells undergoing excision repair and the repair rate in each cell. We then investigated ssUV-induced cyclobutane pyrimidine dimers (CPDs) and 8-oxo-7,8-dihydro-2'-deoxyguanosine (8oxoG) formation and repair by comet assay in keratinocytes and with immunohistochemistry in human skin. Nicotinamide reduced CPDs and 8oxoG in both models and the reduction appeared to be due to enhancement of DNA repair. These results show that nicotinamide enhances two different pathways for repair of UV-induced photolesions, supporting nicotinamide's potential as an inexpensive, convenient and non-toxic agent for skin cancer chemoprevention.

  5. A New Absorbable Synthetic Substitute With Biomimetic Design for Dural Tissue Repair.

    Science.gov (United States)

    Shi, Zhidong; Xu, Tao; Yuan, Yuyu; Deng, Kunxue; Liu, Man; Ke, Yiquan; Luo, Chengyi; Yuan, Tun; Ayyad, Ali

    2016-04-01

    Dural repair products are evolving from animal tissue-derived materials to synthetic materials as well as from inert to absorbable features; most of them lack functional and structural characteristics compared with the natural dura mater. In the present study, we evaluated the properties and tissue repair performance of a new dural repair product with biomimetic design. The biomimetic patch exhibits unique three-dimensional nonwoven microfiber structure with good mechanical strength and biocompatibility. The animal study showed that the biomimetic patch and commercially synthetic material group presented new subdural regeneration at 90 days, with low level inflammatory response and minimal to no adhesion formation detected at each stage. In the biological material group, no new subdural regeneration was observed and severe adhesion between the implant and the cortex occurred at each stage. In clinical case study, there was no cerebrospinal fluid leakage, and all the postoperation observations were normal. The biomimetic structure and proper rate of degradation of the new absorbable dura substitute can guide the meaningful reconstruction of the dura mater, which may provide a novel approach for dural defect repair.

  6. Assessment of primary, oxidative and excision repaired DNA damage in hospital personnel handling antineoplastic drugs.

    Science.gov (United States)

    Villarini, Milena; Dominici, Luca; Piccinini, Renza; Fatigoni, Cristina; Ambrogi, Maura; Curti, Gianluca; Morucci, Piero; Muzi, Giacomo; Monarca, Silvano; Moretti, Massimo

    2011-05-01

    The International Agency for Research on Cancer has classified several antineoplastic drugs in Group 1 (human carcinogens), among which chlorambucil, cyclophosphamide (CP) and tamoxifen, Group 2A (probable human carcinogens), among which cisplatin, etoposide, N-ethyl- and N-methyl-N-nitrosourea, and Group 2B (possible human carcinogens), among which bleomycins, merphalan and mitomycin C. The widespread use of these mutagenic/carcinogenic drugs in the treatment of cancer has led to anxiety about possible genotoxic hazards to medical personnel handling these drugs. The aim of the present study was to evaluate work environment contamination by antineoplastic drugs in a hospital in Central Italy and to assess the genotoxic risks associated with antineoplastic drug handling. The study group comprised 52 exposed subjects and 52 controls. Environmental contamination was assessed by taking wipe samples from different surfaces in preparation and administration rooms and nonwoven swabs were used as pads for the surrogate evaluation of dermal exposure, 5-fluorouracil and cytarabine were chosen as markers of exposure to antineoplastic drugs in the working environment. The actual exposure to antineoplastic drugs was evaluated by determining the urinary excretion of CP. The extent of primary, oxidative and excision repaired DNA damage was measured in peripheral blood leukocytes with the alkaline comet assay. To evaluate the role, if any, of genetic variants in the extent of genotoxic effects related to antineoplastic drug occupational exposure, the study subjects were genotyped for GSTM1, GSTT1, GSTP1 and TP53 polymorphisms. Primary DNA damage significantly increased in leukocytes of exposed nurses compared to controls. The use of personal protective equipment (i.e. gloves and/mask) was associated with a decrease in the extent of primary DNA damage.

  7. Characterization of environmental chemicals with potential for DNA damage using isogenic DNA repair-deficient chicken DT40 cell lines.

    Science.gov (United States)

    Yamamoto, Kimiyo N; Hirota, Kouji; Kono, Koichi; Takeda, Shunichi; Sakamuru, Srilatha; Xia, Menghang; Huang, Ruili; Austin, Christopher P; Witt, Kristine L; Tice, Raymond R

    2011-08-01

    Included among the quantitative high throughput screens (qHTS) conducted in support of the US Tox21 program are those being evaluated for the detection of genotoxic compounds. One such screen is based on the induction of increased cytotoxicity in seven isogenic chicken DT40 cell lines deficient in DNA repair pathways compared to the parental DNA repair-proficient cell line. To characterize the utility of this approach for detecting genotoxic compounds and identifying the type(s) of DNA damage induced, we evaluated nine of 42 compounds identified as positive for differential cytotoxicity in qHTS (actinomycin D, adriamycin, alachlor, benzotrichloride, diglycidyl resorcinol ether, lovastatin, melphalan, trans-1,4-dichloro-2-butene, tris(2,3-epoxypropyl)isocyanurate) and one non-cytotoxic genotoxic compound (2-aminothiamine) for (1) clastogenicity in mutant and wild-type cells; (2) the comparative induction of γH2AX positive foci by melphalan; (3) the extent to which a 72-hr exposure duration increased assay sensitivity or specificity; (4) the use of 10 additional DT40 DNA repair-deficient cell lines to better analyze the type(s) of DNA damage induced; and (5) the involvement of reactive oxygen species in the induction of DNA damage. All compounds but lovastatin and 2-aminothiamine were more clastogenic in at least one DNA repair-deficient cell line than the wild-type cells. The differential responses across the various DNA repair-deficient cell lines provided information on the type(s) of DNA damage induced. The results demonstrate the utility of this DT40 screen for detecting genotoxic compounds, for characterizing the nature of the DNA damage, and potentially for analyzing mechanisms of mutagenesis.

  8. A novel single-cell method provides direct evidence of persistent DNA damage in senescent cells and aged mammalian tissues.

    Science.gov (United States)

    Galbiati, Alessandro; Beauséjour, Christian; d'Adda di Fagagna, Fabrizio

    2017-01-26

    The DNA damage response (DDR) arrests cell cycle progression until DNA lesions, like DNA double-strand breaks (DSBs), are repaired. The presence of DSBs in cells is usually detected by indirect techniques that rely on the accumulation of proteins at DSBs, as part of the DDR. Such detection may be biased, as some factors and their modifications may not reflect physical DNA damage. The dependency on DDR markers of DSB detection tools has left questions unanswered. In particular, it is known that senescent cells display persistent DDR foci, that we and others have proposed to be persistent DSBs, resistant to endogenous DNA repair activities. Others have proposed that these peculiar DDR foci might not be sites of damaged DNA per se but instead stable chromatin modifications, termed DNA-SCARS. Here, we developed a method, named 'DNA damage in situ ligation followed by proximity ligation assay' (DI-PLA) for the detection and imaging of DSBs in cells. DI-PLA is based on the capture of free DNA ends in fixed cells in situ, by ligation to biotinylated double-stranded DNA oligonucleotides, which are next recognized by antibiotin anti-bodies. Detection is enhanced by PLA with a partner DDR marker at the DSB. We validated DI-PLA by demonstrating its ability to detect DSBs induced by various genotoxic insults in cultured cells and tissues. Most importantly, by DI-PLA, we demonstrated that both senescent cells in culture and tissues from aged mammals retain true unrepaired DSBs associated with DDR markers.

  9. Evaluation of radioinduced damage and repair capacity in human breast cancer cells, MCDF-7 and T4-D

    Energy Technology Data Exchange (ETDEWEB)

    Valgode, F.G.S.; Soares, C.R.J.; Bartolini, P.; Okazaki, K. [Instituto de Pesquisas Energeticas e Nucleares IPEN/CNEN-SP, Sao Paulo, SP (Brazil)]. E-mail: kokazaki@ipen.br

    2007-07-01

    Ionizing radiation is an established etiologic agent for breast cancer, but on the other hand it is a therapeutic modality used in cancer treatment. Accumulation of DNA damage and deficient DNA repair are considered as factors of susceptibility that predispose individuals to breast cancer development. In the present study, genetic damage induced by gamma radiation and repair capacity in the target cells, i.e. cells originating of breast cancer, were analyzed using micronucleus test and comet assay (single-cell alkaline gel electrophoresis). So, two breast tumor cell line, MCF-7 and T-47D were irradiated in a {sup 60}Co source (0.722 Gy/min) with various doses (0.5; 1.0; 2.0; 4.0 and 5.0 Gy). Cytogenetic data showed similar spontaneous damage of two cell lines, the radioinduced damage, however, was higher in T-47D, starting from 2 Gy, with a more accelerated proliferation rate than MCF- 7 at all doses analyzed. Both tumor cell lines were capable to repair a considerable part of radioinduced damage within 1 hour after exposure, indicating a relative radioresistance of theses cell lines to the genotoxic action of ionizing radiation. (author)

  10. A DNA2 Homolog Is Required for DNA Damage Repair, Cell Cycle Regulation, and Meristem Maintenance in Plants.

    Science.gov (United States)

    Jia, Ning; Liu, Xiaomin; Gao, Hongbo

    2016-05-01

    Plant meristem cells divide and differentiate in a spatially and temporally regulated manner, ultimately giving rise to organs. In this study, we isolated the Arabidopsis jing he sheng 1 (jhs1) mutant, which exhibited retarded growth, an abnormal pattern of meristem cell division and differentiation, and morphological defects such as fasciation, an irregular arrangement of siliques, and short roots. We identified JHS1 as a homolog of human and yeast DNA Replication Helicase/Nuclease2, which is known to be involved in DNA replication and damage repair. JHS1 is strongly expressed in the meristem of Arabidopsis. The jhs1 mutant was sensitive to DNA damage stress and had an increased DNA damage response, including increased expression of genes involved in DNA damage repair and cell cycle regulation, and a higher frequency of homologous recombination. In the meristem of the mutant plants, cell cycle progression was delayed at the G2 or late S phase and genes essential for meristem maintenance were misregulated. These results suggest that JHS1 plays an important role in DNA replication and damage repair, meristem maintenance, and development in plants. © 2016 American Society of Plant Biologists. All Rights Reserved.

  11. Safety of Intra-Articular Use of Atelocollagen for Enhanced Tissue Repair

    OpenAIRE

    Magarian, Elise M; Vavken, Patrick; Connolly, Susan A; Mastrangelo, Ashley N.; Murray, Martha M.

    2012-01-01

    Collagen is an important biomaterial in intra-articular tissue engineering, but there are unanswered questions about its safety. We hypothesize that the addition of type-I-collagen for primary repair of the Anterior Cruciate Ligament (ACL) might result in a local and systemic reaction in a porcine model after 15 weeks as demonstrated by joint effusion, synovial thickening, elevated intraarticular and systemic leukocyte counts. Further, this reaction might be aggravated by the addition of a pl...

  12. Laser-activated nano-biomaterials for tissue repair and controlled drug release

    Energy Technology Data Exchange (ETDEWEB)

    Matteini, P; Ratto, F; Rossi, F; Pini, R [Institute of Applied Physics ' Nello Carrara' , National Research Council, via Madonna del Piano 10 50019 Sesto Fiorentino (Italy)

    2014-07-31

    We present recent achievements of minimally invasive welding of biological tissue and controlled drug release based on laser-activated nano-biomaterials. In particular, we consider new advancements in the biomedical application of near-IR absorbing gold nano-chromophores as an original solution for the photothermal repair of surgical incisions and as nanotriggers of controlled drug release from hybrid biopolymer scaffolds. (laser biophotonics)

  13. A decreased subchondral trabecular bone tissue elastic modulus is associated with pre-arthritic cartilage damage

    DEFF Research Database (Denmark)

    Day, J; Ding, Ming; van der Linden, JC

    2001-01-01

    In osteoarthritis, one postulate is that changes in the mechanical properties of the subchondral bone layer result in cartilage damage. The goal of this study was to examine changes in subchondral trabecular bone properties at the calcified tissue level in the early stages of cartilage damage....... Finite element models were constructed from microCT scans of trabectilar bone from the proximal tibia of donors with mild cartilage damage and from normal donors. In the donors with cartilage damage, macroscopic damage was present only in the medial compartment. The effective tissue elastic moduli were...... determined using a combination of finite element models and mechanical testing. The bone tissue modulus was reduced by 60% in the medial condyle of the cases with cartilage damage compared to the control specimens. Neither the presence of cartilage damage nor the anatomic site (medial vs. lateral) affected...

  14. Thermodynamics of the DNA damage repair steps of human 8-oxoguanine DNA glycosylase.

    Directory of Open Access Journals (Sweden)

    Nikita A Kuznetsov

    Full Text Available Human 8-oxoguanine DNA glycosylase (hOGG1 is a key enzyme responsible for initiating the base excision repair of 7,8-dihydro-8-oxoguanosine (oxoG. In this study a thermodynamic analysis of the interaction of hOGG1 with specific and non-specific DNA-substrates is performed based on stopped-flow kinetic data. The standard Gibbs energies, enthalpies and entropies of specific stages of the repair process were determined via kinetic measurements over a temperature range using the van't Hoff approach. The three steps which are accompanied with changes in the DNA conformations were detected via 2-aminopurine fluorescence in the process of binding and recognition of damaged oxoG base by hOGG1. The thermodynamic analysis has demonstrated that the initial step of the DNA substrates binding is mainly governed by energy due to favorable interactions in the process of formation of the recognition contacts, which results in negative enthalpy change, as well as due to partial desolvation of the surface between the DNA and enzyme, which results in positive entropy change. Discrimination of non-specific G base versus specific oxoG base is occurring in the second step of the oxoG-substrate binding. This step requires energy consumption which is compensated by the positive entropy contribution. The third binding step is the final adjustment of the enzyme/substrate complex to achieve the catalytically competent state which is characterized by large endothermicity compensated by a significant increase of entropy originated from the dehydration of the DNA grooves.

  15. Oxidative DNA damage and repair in skeletal muscle of humans exposed to high-altitude hypoxia

    DEFF Research Database (Denmark)

    Lundby, Carsten; Pilegaard, Henriette; van Hall, Gerrit

    2003-01-01

    ) was unaltered by prolonged hypoxia, in accordance with the notion that HO-1 is an acute stress response protein. In conclusion, our data indicate high-altitude hypoxia may serve as a good model for oxidative stress and that antioxidant genes are not upregulated in muscle tissue by prolonged hypoxia despite......Recent research suggests that high-altitude hypoxia may serve as a model for prolonged oxidative stress in healthy humans. In this study, we investigated the consequences of prolonged high-altitude hypoxia on the basal level of oxidative damage to nuclear DNA in muscle cells, a major oxygen...

  16. Beryllium chloride-induced oxidative DNA damage and alteration in the expression patterns of DNA repair-related genes.

    Science.gov (United States)

    Attia, Sabry M; Harisa, Gamaleldin I; Hassan, Memy H; Bakheet, Saleh A

    2013-09-01

    Beryllium metal has physical properties that make its use essential for very specific applications, such as medical diagnostics, nuclear/fusion reactors and aerospace applications. Because of the widespread human exposure to beryllium metals and the discrepancy of the genotoxic results in the reported literature, detail assessments of the genetic damage of beryllium are warranted. Mice exposed to beryllium chloride at an oral dose of 23mg/kg for seven consecutive days exhibited a significant increase in the level of DNA-strand breaking and micronuclei formation as detected by a bone marrow standard comet assay and micronucleus test. Whereas slight beryllium chloride-induced oxidative DNA damage was detected following formamidopyrimidine DNA glycosylase digestion, digestion with endonuclease III resulted in considerable increases in oxidative DNA damage after the 11.5 and 23mg/kg/day treatment as detected by enzyme-modified comet assays. Increased 8-hydroxydeoxyguanosine was also directly correlated with increased bone marrow micronuclei formation and DNA strand breaks, which further confirm the involvement of oxidative stress in the induction of bone marrow genetic damage after exposure to beryllium chloride. Gene expression analysis on the bone marrow cells from beryllium chloride-exposed mice showed significant alterations in genes associated with DNA damage repair. Therefore, beryllium chloride may cause genetic damage to bone marrow cells due to the oxidative stress and the induced unrepaired DNA damage is probably due to the down-regulation in the expression of DNA repair genes, which may lead to genotoxicity and eventually cause carcinogenicity.

  17. A Stereological Method for the Quantitative Evaluation of Cartilage Repair Tissue

    Science.gov (United States)

    Nyengaard, Jens Randel; Lind, Martin; Spector, Myron

    2015-01-01

    Objective To implement stereological principles to develop an easy applicable algorithm for unbiased and quantitative evaluation of cartilage repair. Design Design-unbiased sampling was performed by systematically sectioning the defect perpendicular to the joint surface in parallel planes providing 7 to 10 hematoxylin–eosin stained histological sections. Counting windows were systematically selected and converted into image files (40-50 per defect). The quantification was performed by two-step point counting: (1) calculation of defect volume and (2) quantitative analysis of tissue composition. Step 2 was performed by assigning each point to one of the following categories based on validated and easy distinguishable morphological characteristics: (1) hyaline cartilage (rounded cells in lacunae in hyaline matrix), (2) fibrocartilage (rounded cells in lacunae in fibrous matrix), (3) fibrous tissue (elongated cells in fibrous tissue), (4) bone, (5) scaffold material, and (6) others. The ability to discriminate between the tissue types was determined using conventional or polarized light microscopy, and the interobserver variability was evaluated. Results We describe the application of the stereological method. In the example, we assessed the defect repair tissue volume to be 4.4 mm3 (CE = 0.01). The tissue fractions were subsequently evaluated. Polarized light illumination of the slides improved discrimination between hyaline cartilage and fibrocartilage and increased the interobserver agreement compared with conventional transmitted light. Conclusion We have applied a design-unbiased method for quantitative evaluation of cartilage repair, and we propose this algorithm as a natural supplement to existing descriptive semiquantitative scoring systems. We also propose that polarized light is effective for discrimination between hyaline cartilage and fibrocartilage. PMID:26069715

  18. A Stereological Method for the Quantitative Evaluation of Cartilage Repair Tissue.

    Science.gov (United States)

    Foldager, Casper Bindzus; Nyengaard, Jens Randel; Lind, Martin; Spector, Myron

    2015-04-01

    To implement stereological principles to develop an easy applicable algorithm for unbiased and quantitative evaluation of cartilage repair. Design-unbiased sampling was performed by systematically sectioning the defect perpendicular to the joint surface in parallel planes providing 7 to 10 hematoxylin-eosin stained histological sections. Counting windows were systematically selected and converted into image files (40-50 per defect). The quantification was performed by two-step point counting: (1) calculation of defect volume and (2) quantitative analysis of tissue composition. Step 2 was performed by assigning each point to one of the following categories based on validated and easy distinguishable morphological characteristics: (1) hyaline cartilage (rounded cells in lacunae in hyaline matrix), (2) fibrocartilage (rounded cells in lacunae in fibrous matrix), (3) fibrous tissue (elongated cells in fibrous tissue), (4) bone, (5) scaffold material, and (6) others. The ability to discriminate between the tissue types was determined using conventional or polarized light microscopy, and the interobserver variability was evaluated. We describe the application of the stereological method. In the example, we assessed the defect repair tissue volume to be 4.4 mm(3) (CE = 0.01). The tissue fractions were subsequently evaluated. Polarized light illumination of the slides improved discrimination between hyaline cartilage and fibrocartilage and increased the interobserver agreement compared with conventional transmitted light. We have applied a design-unbiased method for quantitative evaluation of cartilage repair, and we propose this algorithm as a natural supplement to existing descriptive semiquantitative scoring systems. We also propose that polarized light is effective for discrimination between hyaline cartilage and fibrocartilage.

  19. Modeling electrical power absorption and thermally-induced biological tissue damage.

    Science.gov (United States)

    Zohdi, T I

    2014-01-01

    This work develops a model for thermally induced damage from high current flow through biological tissue. Using the first law of thermodynamics, the balance of energy produced by the current and the energy absorbed by the tissue are investigated. The tissue damage is correlated with an evolution law that is activated upon exceeding a temperature threshold. As an example, the Fung material model is used. For certain parameter choices, the Fung material law has the ability to absorb relatively significant amounts of energy, due to its inherent exponential response character, thus, to some extent, mitigating possible tissue damage. Numerical examples are provided to illustrate the model's behavior.

  20. Non-Fourier based thermal-mechanical tissue damage prediction for thermal ablation.

    Science.gov (United States)

    Li, Xin; Zhong, Yongmin; Smith, Julian; Gu, Chengfan

    2017-01-02

    Prediction of tissue damage under thermal loads plays important role for thermal ablation planning. A new methodology is presented in this paper by combing non-Fourier bio-heat transfer, constitutive elastic mechanics as well as non-rigid motion of dynamics to predict and analyze thermal distribution, thermal-induced mechanical deformation and thermal-mechanical damage of soft tissues under thermal loads. Simulations and comparison analysis demonstrate that the proposed methodology based on the non-Fourier bio-heat transfer can account for the thermal-induced mechanical behaviors of soft tissues and predict tissue thermal damage more accurately than classical Fourier bio-heat transfer based model.

  1. Delivery of human mesenchymal adipose-derived stem cells restores multiple urological dysfunctions in a rat model mimicking radical prostatectomy damages through tissue-specific paracrine mechanisms.

    Science.gov (United States)

    Yiou, René; Mahrouf-Yorgov, Meriem; Trébeau, Céline; Zanaty, Marc; Lecointe, Cécile; Souktani, Richard; Zadigue, Patricia; Figeac, Florence; Rodriguez, Anne-Marie

    2016-02-01

    Urinary incontinence (UI) and erectile dysfunction (ED) are the most common functional urological disorders and the main sequels of radical prostatectomy (RP) for prostate cancer. Mesenchymal stem cell (MSC) therapy holds promise for repairing tissue damage due to RP. Because animal studies accurately replicating post-RP clinical UI and ED are lacking, little is known about the mechanisms underlying the urological benefits of MSC in this setting. To determine whether and by which mechanisms MSC can repair damages to both striated urethral sphincter (SUS) and penis in the same animal, we delivered human multipotent adipose stem cells, used as MSC model, in an immunocompetent rat model replicating post-RP UI and ED. In this model, we demonstrated by using noninvasive methods in the same animal from day 7 to day 90 post-RP injury that MSC administration into both the SUS and the penis significantly improved urinary continence and erectile function. The regenerative effects of MSC therapy were not due to transdifferentiation and robust engraftment at injection sites. Rather, our results suggest that MSC benefits in both target organs may involve a paracrine process with not only soluble factor release by the MSC but also activation of the recipient's secretome. These two effects of MSC varied across target tissues and damaged-cell types. In conclusion, our work provides new insights into the regenerative properties of MSC and supports the ability of MSC from a single source to repair multiple types of damage, such as those seen after RP, in the same individual.

  2. Hyaluronic acid hydrogels with IKVAV peptides for tissue repair and axonal regeneration in an injured rat brain

    Energy Technology Data Exchange (ETDEWEB)

    Wei, Y T [Biomaterials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Tian, W M [Biomaterials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Yu, X [Biomaterials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Cui, F Z [Biomaterials Laboratory, Department of Materials Science and Engineering, Tsinghua University, Beijing, 100084 (China); Hou, S P [Beijing Institute of Neuroscience, Capital University of Medical Sciences, Beijing, 100054 (China); Xu, Q Y [Beijing Institute of Neuroscience, Capital University of Medical Sciences, Beijing, 100054 (China); Lee, In-Seop [Institute of Physics and Applied Physics, and Atomic-scale Surface Science Research Center, Yonsei University, Seoul 120-749 (Korea, Republic of)

    2007-09-15

    A biocompatible hydrogel of hyaluronic acid with the neurite-promoting peptide sequence of IKVAV was synthesized. The characterization of the hydrogel shows an open porous structure and a large surface area available for cell interaction. Its ability to promote tissue repair and axonal regeneration in the lesioned rat cerebrum is also evaluated. After implantation, the polymer hydrogel repaired the tissue defect and formed a permissive interface with the host tissue. Axonal growth occurred within the microstructure of the network. Within 6 weeks the polymer implant was invaded by host-derived tissue, glial cells, blood vessels and axons. Such a hydrogel matrix showed the properties of neuron conduction. It has the potential to repair tissue defects in the central nervous system by promoting the formation of a tissue matrix and axonal growth by replacing the lost tissue.

  3. Reactive oxygen species, DNA damage, and error-prone repair: a model for genomic instability with progression in myeloid leukemia?

    Science.gov (United States)

    Rassool, Feyruz V; Gaymes, Terry J; Omidvar, Nader; Brady, Nicola; Beurlet, Stephanie; Pla, Marika; Reboul, Murielle; Lea, Nicholas; Chomienne, Christine; Thomas, Nicholas S B; Mufti, Ghulam J; Padua, Rose Ann

    2007-09-15

    Myelodysplastic syndromes (MDS) comprise a heterogeneous group of disorders characterized by ineffective hematopoiesis, with an increased propensity to develop acute myelogenous leukemia (AML). The molecular basis for MDS progression is unknown, but a key element in MDS disease progression is loss of chromosomal material (genomic instability). Using our two-step mouse model for myeloid leukemic disease progression involving overexpression of human mutant NRAS and BCL2 genes, we show that there is a stepwise increase in the frequency of DNA damage leading to an increased frequency of error-prone repair of double-strand breaks (DSB) by nonhomologous end-joining. There is a concomitant increase in reactive oxygen species (ROS) in these transgenic mice with disease progression. Importantly, RAC1, an essential component of the ROS-producing NADPH oxidase, is downstream of RAS, and we show that ROS production in NRAS/BCL2 mice is in part dependent on RAC1 activity. DNA damage and error-prone repair can be decreased or reversed in vivo by N-acetyl cysteine antioxidant treatment. Our data link gene abnormalities to constitutive DNA damage and increased DSB repair errors in vivo and provide a mechanism for an increase in the error rate of DNA repair with MDS disease progression. These data suggest treatment strategies that target RAS/RAC pathways and ROS production in human MDS/AML.

  4. NDR1 modulates the UV-induced DNA-damage checkpoint and nucleotide excision repair

    Energy Technology Data Exchange (ETDEWEB)

    Park, Jeong-Min; Choi, Ji Ye [Department of Biological Science, Dong-A University, Busan (Korea, Republic of); Yi, Joo Mi [Research Center, Dongnam Institute of Radiological & Medical Sciences, Busan (Korea, Republic of); Chung, Jin Woong; Leem, Sun-Hee; Koh, Sang Seok [Department of Biological Science, Dong-A University, Busan (Korea, Republic of); Kang, Tae-Hong, E-mail: thkang@dau.ac.kr [Department of Biological Science, Dong-A University, Busan (Korea, Republic of)

    2015-06-05

    Nucleotide excision repair (NER) is the sole mechanism of UV-induced DNA lesion repair in mammals. A single round of NER requires multiple components including seven core NER factors, xeroderma pigmentosum A–G (XPA–XPG), and many auxiliary effector proteins including ATR serine/threonine kinase. The XPA protein helps to verify DNA damage and thus plays a rate-limiting role in NER. Hence, the regulation of XPA is important for the entire NER kinetic. We found that NDR1, a novel XPA-interacting protein, modulates NER by modulating the UV-induced DNA-damage checkpoint. In quiescent cells, NDR1 localized mainly in the cytoplasm. After UV irradiation, NDR1 accumulated in the nucleus. The siRNA knockdown of NDR1 delayed the repair of UV-induced cyclobutane pyrimidine dimers in both normal cells and cancer cells. It did not, however, alter the expression levels or the chromatin association levels of the core NER factors following UV irradiation. Instead, the NDR1-depleted cells displayed reduced activity of ATR for some set of its substrates including CHK1 and p53, suggesting that NDR1 modulates NER indirectly via the ATR pathway. - Highlights: • NDR1 is a novel XPA-interacting protein. • NDR1 accumulates in the nucleus in response to UV irradiation. • NDR1 modulates NER (nucleotide excision repair) by modulating the UV-induced DNA-damage checkpoint response.

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

    Science.gov (United States)

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

    2015-05-01

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

  6. Differential repair of UV damage in Saccharomyces cerevisiae is cell cycle dependent.

    Science.gov (United States)

    Terleth, C; Waters, R; Brouwer, J; van de Putte, P

    1990-09-01

    In the yeast Saccharomyces cerevisiae the transcriptionally active MAT alpha locus is repaired preferentially to the inactive HML alpha locus after UV irradiation. Here we analysed the repair of both loci after irradiating yeast cells at different stages of the mitotic cell cycle. In all stages repair of the active MAT alpha locus occurs at a rate of 30% removal of dimers per hour after a UV dose of 60 J/m2. The inactive HML alpha is repaired as efficiently as MAT alpha following irradiation in G2 whereas repair of HML alpha is less efficient in the other stages. Thus differential repair is observed in G1 and S but not in G2. Apparently, in G2 a chromatin structure exists in which repair does not discriminate between transcriptionally active and inactive DNA or, alternatively, an additional repair mechanism might exist which is only operational during G2.

  7. BRCA1-associated exclusion of 53BP1 from DNA damage sites underlies temporal control of DNA repair

    Science.gov (United States)

    Chapman, J. Ross; Sossick, Alex J.; Boulton, Simon J.; Jackson, Stephen P.

    2012-01-01

    Summary Following irradiation, numerous DNA-damage-responsive proteins rapidly redistribute into microscopically visible subnuclear aggregates, termed ionising-radiation-induced foci (IRIF). How the enrichment of proteins on damaged chromatin actually relates to DNA repair remains unclear. Here, we use super-resolution microscopy to examine the spatial distribution of BRCA1 and 53BP1 proteins within single IRIF at subdiffraction-limit resolution, yielding an unprecedented increase in detail that was not previously apparent by conventional microscopy. Consistent with a role for 53BP1 in promoting DNA double-strand break repair by non-homologous end joining, 53BP1 enrichment in IRIF is most prominent in the G0/G1 cell cycle phases, where it is enriched in dense globular structures. By contrast, as cells transition through S phase, the recruitment of BRCA1 into the core of IRIF is associated with an exclusion of 53BP1 to the focal periphery, leading to an overall reduction of 53BP1 occupancy at DNA damage sites. Our data suggest that the BRCA1-associated IRIF core corresponds to chromatin regions associated with repair by homologous recombination, and the enrichment of BRCA1 in IRIF represents a temporal switch in the DNA repair program. We propose that BRCA1 antagonises 53BP1-dependent DNA repair in S phase by inhibiting its interaction with chromatin proximal to damage sites. Furthermore, the genomic instability exhibited by BRCA1-deficient cells might result from a failure to efficiently exclude 53BP1 from such regions during S phase. PMID:22553214

  8. Phosphoramide mustard exposure induces DNA adduct formation and the DNA damage repair response in rat ovarian granulosa cells.

    Science.gov (United States)

    Ganesan, Shanthi; Keating, Aileen F

    2015-02-01

    Phosphoramide mustard (PM), the ovotoxic metabolite of the anti-cancer agent cyclophosphamide (CPA), destroys rapidly dividing cells by forming NOR-G-OH, NOR-G and G-NOR-G adducts with DNA, potentially leading to DNA damage. A previous study demonstrated that PM induces ovarian DNA damage in rat ovaries. To investigate whether PM induces DNA adduct formation, DNA damage and induction of the DNA repair response, rat spontaneously immortalized granulosa cells (SIGCs) were treated with vehicle control (1% DMSO) or PM (3 or 6μM) for 24 or 48h. Cell viability was reduced (Padduct was detected after 24h of 6μM PM exposure, while the more cytotoxic G-NOR-G DNA adduct was formed after 48h by exposure to both PM concentrations. Phosphorylated H2AX (γH2AX), a marker of DNA double stranded break occurrence, was also increased by PM exposure, coincident with DNA adduct formation. Additionally, induction of genes (Atm, Parp1, Prkdc, Xrcc6, and Brca1) and proteins (ATM, γH2AX, PARP-1, PRKDC, XRCC6, and BRCA1) involved in DNA repair were observed in both a time- and dose-dependent manner. These data support that PM induces DNA adduct formation in ovarian granulosa cells, induces DNA damage and elicits the ovarian DNA repair response.

  9. Genetic polymorphisms of DNA repair genes and chromosomal damage in workers exposed to 1,3-butadiene.

    Science.gov (United States)

    Wang, Qi; Wang, Ai-hong; Tan, Hong-shan; Feng, Nan-nan; Ye, Yun-jie; Feng, Xiao-qing; Liu, Geoffrey; Zheng, Yu-xin; Xia, Zhao-lin

    2010-05-01

    The base excision repair (BER) pathway is important in repairing DNA damage incurred from occupational exposure to 1,3-butadiene (BD). This study examines the relationship between inherited polymorphisms of the BER pathway (x-ray repair cross-complementing group 1 (XRCC1) Arg194Trp, Arg280His, Arg399Gln, T-77C, ADPRT Val762Ala, MGMT Leu84Phe and APE1 Asp148Glu) and chromosomal damage in BD-exposed workers, using the cytokinesis-blocked (CB) micronucleus (MN) assay in peripheral lymphocytes of 166 workers occupationally exposed to BD and 41 non-exposed healthy individuals. The MN frequency of exposed workers (3.39 +/- 2.42) per thousand was higher than that of the non-exposed groups (1.48 +/- 1.26) per thousand (P damage among BD-exposed workers. In workers exposed to BD, multiple BER polymorphisms and a XRCC1 haplotype were associated with differential levels of chromosome damage.

  10. Vascular tissue is the first site of damage in the TCDD-exposed fish embryo

    Energy Technology Data Exchange (ETDEWEB)

    Cantrell, S.; Tillitt, D. [Midwest Science Center, Columbia, MO (United States); Hannink, M. [Univ. of Missouri, Columbia, MO (United States). Biochemistry Dept.

    1995-12-31

    The planar halogenated hydrocarbons (PHHs) are a group of environmental contaminants that exert adverse biological effects in most vertebrate organisms. Embryonic development is the most sensitive life stage to the effects of these compounds. The reason for the enhanced sensitivity to PHHs during early life stages is unknown. To study TCDD-induced embryotoxicity, a fish species the medaka was the organism of choice. The authors localized the initial site of tissue damage in the developing embryo and investigated the mechanism of TCDD-induced tissue damage. There were three parts to this study, (1) observation of morphological anomalies in the TCDD-treated embryo, (2) immunohistochemical detection of DNA damage in the tissues of TCDD-treated embryos, and (3) test the ability of an antioxidant to delay the onset of initial tissue damage. Morphological observations show that the first visual lesions that occur in the TCDD treated embryo occur at stage 36, about day 6 post fertilization. The lesions are localized in the cardiac vasculature. Immunohistochemical staining, using the terminal nucleotide transferase assay (TdT-assay) which detects DNA damage showed that the initial site of tissue damage was in the vasculature in the cardiac region. Tissue damage was detected in neural tissue and muscle tissue at later time points. TCDD is known to induce oxidative stress in a variety of organisms, therefore; the authors tested to see if oxidative stress may play a role in TCDD-induced embryotoxicity. The TCDD-treated embryos were cultured in the antioxidant N-acetyl cysteine (NAC) and the morphological observations and TdT-assay were repeated. They found that NAC was able to delay the onset of tissue damage and NAC was able to reduce total mortality in the embryo. The results from this study indicate that the cardiac vasculature is the initial site of tissue damage.

  11. Phosphoramide mustard exposure induces DNA adduct formation and the DNA damage repair response in rat ovarian granulosa cells

    Energy Technology Data Exchange (ETDEWEB)

    Ganesan, Shanthi, E-mail: shanthig@iastate.edu; Keating, Aileen F., E-mail: akeating@iastate.edu

    2015-02-01

    Phosphoramide mustard (PM), the ovotoxic metabolite of the anti-cancer agent cyclophosphamide (CPA), destroys rapidly dividing cells by forming NOR-G-OH, NOR-G and G-NOR-G adducts with DNA, potentially leading to DNA damage. A previous study demonstrated that PM induces ovarian DNA damage in rat ovaries. To investigate whether PM induces DNA adduct formation, DNA damage and induction of the DNA repair response, rat spontaneously immortalized granulosa cells (SIGCs) were treated with vehicle control (1% DMSO) or PM (3 or 6 μM) for 24 or 48 h. Cell viability was reduced (P < 0.05) after 48 h of exposure to 3 or 6 μM PM. The NOR-G-OH DNA adduct was detected after 24 h of 6 μM PM exposure, while the more cytotoxic G-NOR-G DNA adduct was formed after 48 h by exposure to both PM concentrations. Phosphorylated H2AX (γH2AX), a marker of DNA double stranded break occurrence, was also increased by PM exposure, coincident with DNA adduct formation. Additionally, induction of genes (Atm, Parp1, Prkdc, Xrcc6, and Brca1) and proteins (ATM, γH2AX, PARP-1, PRKDC, XRCC6, and BRCA1) involved in DNA repair were observed in both a time- and dose-dependent manner. These data support that PM induces DNA adduct formation in ovarian granulosa cells, induces DNA damage and elicits the ovarian DNA repair response. - Highlights: • PM forms ovarian DNA adducts. • DNA damage marker γH2AX increased by PM exposure. • PM induces ovarian DNA double strand break repair.

  12. Modulation of DNA Damage and Repair Pathways by Human Tumour Viruses

    Directory of Open Access Journals (Sweden)

    Robert Hollingworth

    2015-05-01

    Full Text Available With between 10% and 15% of human cancers attributable to viral infection, there is great interest, from both a scientific and clinical viewpoint, as to how these pathogens modulate host cell functions. Seven human tumour viruses have been identified as being involved in the development of specific malignancies. It has long been known that the introduction of chromosomal aberrations is a common feature of viral infections. Intensive research over the past two decades has subsequently revealed that viruses specifically interact with cellular mechanisms responsible for the recognition and repair of DNA lesions, collectively known as the DNA damage response (DDR. These interactions can involve activation and deactivation of individual DDR pathways as well as the recruitment of specific proteins to sites of viral replication. Since the DDR has evolved to protect the genome from the accumulation of deleterious mutations, deregulation is inevitably associated with an increased risk of tumour formation. This review summarises the current literature regarding the complex relationship between known human tumour viruses and the DDR and aims to shed light on how these interactions can contribute to genomic instability and ultimately the development of human cancers.

  13. Damage-induced hydrolyses modelling of biodegradable polymers for tendons and ligaments repair.

    Science.gov (United States)

    Vieira, André C; Guedes, Rui M; Tita, Volnei

    2015-09-18

    The use of biodegradable synthetic grafts to repair injured ligaments may overcome the disadvantages of other solutions. Apart from biological compatibility, these devices shall also be functionally compatible and temporarily displayed, during the healing process, adequate mechanical support. Laxity of these devices is an important concern. This can cause failure since it may result in joint instability. Laxity results from a progressive accumulation of plastic strain during the cyclic loading. The functional compatibility of a biodegradable synthetic graft and, therefore, the global mechanical properties of the scaffold during degradation, can be optimised using computer-aiding and numerical tools. Therefore, in this work, the ability of numerical tools to predict the mechanical behaviour of the device during its degradation is discussed. Computational approaches based on elastoplastic and viscoplastic constitutive models are also presented. These models enable to simulate the plastic strain accumulation. These computational approaches, where the material model parameters depend on the hydrolytic degradation damage, are calibrated using experimental data measured from biodegradable suture fibres at different degradation steps. Due to durability requirements the selected materials are polydioxone (PDO) and polylactic acid and poly-caprolactone blend (PLA-PCL). Computational approaches investigated are able to predict well the experimental results for both materials, in full strain range until rupture and for different degradation steps. These approaches can be further used in more complex fibrous structures, to predict its global mechanical behaviour during degradation process.

  14. Evaluating the repair of DNA derived from formalin-fixed paraffin-embedded tissues prior to genomic profiling by SNP-CGH analysis.

    Science.gov (United States)

    Hosein, Abdel Nasser; Song, Sarah; McCart Reed, Amy E; Jayanthan, Janani; Reid, Lynne E; Kutasovic, Jamie R; Cummings, Margaret C; Waddell, Nic; Lakhani, Sunil R; Chenevix-Trench, Georgia; Simpson, Peter T

    2013-06-01

    Pathology archives contain vast resources of clinical material in the form of formalin-fixed paraffin-embedded (FFPE) tissue samples. Owing to the methods of tissue fixation and storage, the integrity of DNA and RNA available from FFPE tissue is compromized, which means obtaining informative data regarding epigenetic, genomic, and expression alterations can be challenging. Here, we have investigated the utility of repairing damaged DNA derived from FFPE tumors prior to single-nucleotide polymorphism (SNP) arrays for whole-genome DNA copy number analysis. DNA was extracted from FFPE samples spanning five decades, involving tumor material obtained from surgical specimens and postmortems. Various aspects of the protocol were assessed, including the method of DNA extraction, the role of Quality Control quantitative PCR (qPCR) in predicting sample success, and the effect of DNA restoration on assay performance, data quality, and the prediction of copy number aberrations (CNAs). DNA that had undergone the repair process yielded higher SNP call rates, reduced log R ratio variance, and improved calling of CNAs compared with matched FFPE DNA not subjected to repair. Reproducible mapping of genomic break points and detection of focal CNAs representing high-level gains and homozygous deletions (HD) were possible, even on autopsy material obtained in 1974. For example, DNA amplifications at the ERBB2 and EGFR gene loci and a HD mapping to 13q14.2 were validated using immunohistochemistry, in situ hybridization, and qPCR. The power of SNP arrays lies in the detection of allele-specific aberrations; however, this aspect of the analysis remains challenging, particularly in the distinction between loss of heterozygosity (LOH) and copy neutral LOH. In summary, attempting to repair DNA that is damaged during fixation and storage may be a useful pretreatment step for genomic studies of large archival FFPE cohorts with long-term follow-up or for understanding rare cancer types, where

  15. Detection of abnormalities in the superficial zone of cartilage repaired using a tissue engineered construct derived from synovial stem cells

    OpenAIRE

    Ando, W.; FUJIE, H; Moriguchi, Y.; Nansai, R.; Shimomura, K.; DA Hart; Yoshikawa, H; Nakamura, N.

    2012-01-01

    The present study investigated the surface structure and mechanical properties of repair cartilage generated from a tissue engineered construct (TEC) derived from synovial mesenchymal stem cells at six months post-implantation compared to those of uninjured cartilage. TEC-mediated repair tissue was cartilaginous with Safranin O staining, and had comparable macro-scale compressive properties with uninjured cartilage. However, morphological assessments revealed that the superficial zone of TEC-...

  16. Hydrogel-delivered brain-derived neurotrophic factor promotes tissue repair and recovery after stroke.

    Science.gov (United States)

    Cook, Douglas J; Nguyen, Cynthia; Chun, Hyun N; L Llorente, Irene; Chiu, Abraham S; Machnicki, Michal; Zarembinski, Thomas I; Carmichael, S Thomas

    2017-03-01

    Stroke is the leading cause of adult disability. Systemic delivery of candidate neural repair therapies is limited by the blood-brain barrier and off-target effects. We tested a bioengineering approach for local depot release of BDNF from the infarct cavity for neural repair in chronic periods after stroke. The brain release levels of a hyaluronic acid hydrogel + BDNF were tested in several stroke models in mouse (strains C57Bl/6, DBA) and non-human primate ( Macaca fascicularis) and tracked with MRI. The behavioral recovery effects of hydrogel + BDNF and the effects on tissue repair outcomes were determined. Hydrogel-delivered BDNF diffuses from the stroke cavity into peri-infarct tissue over 3 weeks in two mouse stroke models, compared with 1 week for direct BDNF injection. Hydrogel delivery of BDNF promotes recovery of motor function. Mapping of motor system connections indicates that hydrogel-BDNF induces axonal sprouting within existing cortical and cortico-striatal systems. Pharmacogenetic studies show that hydrogel-BDNF induces the initial migration of immature neurons into the peri-infarct cortex and their long-term survival. In chronic stroke in the non-human primate, hydrogel-released BDNF can be detected up to 2 cm from the infarct, a distance relevant to human functional recovery in stroke. The hydrogel can be tracked by MRI in mouse and primate.

  17. Cellular proliferation and regeneration following tissue damage. Progress report. [Eyes

    Energy Technology Data Exchange (ETDEWEB)

    Harding, C.V.

    1976-10-01

    Results are reported from a study of wound healing in tissues of the eye, particularly lens, cornea, and surrounding tissues. The reactions of these tissues to mechanical injuries, as well as injuries induced by chemotoxic agents were studied. It is postulated that a better understanding of the basic reactions of the eye to injurious agents may be of importance in the evaluation of potential environmental hazards.

  18. No effect of 600 grams fruit and vegetables per day on oxidative DNA damage and repair in healthy nonsmokers

    DEFF Research Database (Denmark)

    Moller, P.; Vogel, Ulla Birgitte; Pedersen, A.;

    2003-01-01

    In several epidemiological studies, high intakes of fruits and vegetables have been associated with a lower incidence of cancer. Theoretically, intake of antioxidants by consumption of fruits and vegetables should protect against reactive oxygen species and decrease the formation of oxidative DNA......-oxo-2'-deoxyguanine was measured in urine. The expressions of oxoguanine glycosylase I and excision repair cross complementing I DNA repair genes, determined by real-time reverse transcription-PCR of mRNAs, were investigated in leukocytes. Consumption of fruits and vegetables or vitamins and minerals...... had no effect on oxidative DNA damage measured in mononuclear cell DNA or urine. Hydrogen peroxide sensitivity, detected by the comet assay, did not differ between the groups. Expression of excision repair cross complementing I and oxoguanine glycosylase I in leukocytes was not related to the diet...

  19. Ultraviolet damage, DNA repair and vitamin D in nonmelanoma skin cancer and in malignant melanoma: an update.

    Science.gov (United States)

    Reichrath, Jörg; Rass, Knuth

    2014-01-01

    Skin exposure with UV radiation (UV) is the main cause of skin cancer development. Epidemiological data indicate that excessive or cumulative UV exposure takes place years and decades before the resulting malignancies arise. The most important defense mechanisms that protect human skin against UV radiation involve melanin synthesis and active repair mechanisms. DNA is the major target of direct or indirect UV-induced cellular damage. Low pigmentation capacity in white Caucasians and rare congenital defects in DNA repair are mainly responsible for protection failures. The important function of nucleotide excision DNA repair (NER) to protect against skin cancer becomes obvious by the rare genetic disease xeroderma pigmentosum, in which diverse NER genes are mutated. In animal models, it has been demonstrated that UVB is more effective to induce skin cancer than UVA. UV-induced DNA photoproducts are able to cause specific mutations (UV-signature) in susceptible genes for squamous cell carcinoma (SCC) and basal cell carcinoma (BCC). In SCC development, UV-signature mutations in the p53 tumor suppressor gene are the most common event, as precancerous lesions reveal -80% and SCCs > 90% UV-specific p53 mutations. Mutations in Hedgehog pathway related genes, especially PTCH1, are well known to represent the most significant pathogenic event in BCC. However, specific UV-induced mutations can be found only in -50% of sporadic BCCs. Thus, cumulative UVB radiation cannot be considered to represent the only etiologic risk factor for BCC development. During the last decades, experimental animal models, including genetically engineered mice, the Xiphophorus hybrid fish, the South American oppossum and human skin xenografts, have further elucidated the important role of the DNA repair system in the multi-step process of UV-induced melanomagenesis. An increasing body of evidence now indicates that nucleotide excision repair is not the only DNA repair pathway that is involved in UV

  20. Repair Effect of Seaweed Polysaccharides with Different Contents of Sulfate Group and Molecular Weights on Damaged HK-2 Cells

    Directory of Open Access Journals (Sweden)

    Poonam Bhadja

    2016-05-01

    Full Text Available The structure–activity relationships and repair mechanism of six low-molecular-weight seaweed polysaccharides (SPSs on oxalate-induced damaged human kidney proximal tubular epithelial cells (HK-2 were investigated. These SPSs included Laminaria japonica polysaccharide, degraded Porphyra yezoensis polysaccharide, degraded Gracilaria lemaneiformis polysaccharide, degraded Sargassum fusiforme polysaccharide, Eucheuma gelatinae polysaccharide, and degraded Undaria pinnatifida polysaccharide. These SPSs have a narrow difference of molecular weight (from 1968 to 4020 Da after degradation by controlling H2O2 concentration. The sulfate group (–SO3H content of the six SPSs was 21.7%, 17.9%, 13.3%, 8.2%, 7.0%, and 5.5%, respectively, and the –COOH contents varied between 1.0% to 1.7%. After degradation, no significant difference was observed in the contents of characteristic –SO3H and –COOH groups of polysaccharides. The repair effect of polysaccharides was determined using cell-viability test by CCK-8 assay and cell-morphology test by hematoxylin-eosin staining. The results revealed that these SPSs within 0.1–100 μg/mL did not express cytotoxicity in HK-2 cells, and each polysaccharide had a repair effect on oxalate-induced damaged HK-2 cells. Simultaneously, the content of polysaccharide –SO3H was positively correlated with repair ability. Furthermore, the low-molecular-weight degraded polysaccharides showed better repair activity on damaged HK-2 cells than their undegraded counterpart. Our results can provide reference for inhibiting the formation of kidney stones and for developing original anti-stone polysaccharide drugs.

  1. Kaempferol induces DNA damage and inhibits DNA repair associated protein expressions in human promyelocytic leukemia HL-60 cells.

    Science.gov (United States)

    Wu, Lung-Yuan; Lu, Hsu-Feng; Chou, Yu-Cheng; Shih, Yung-Luen; Bau, Da-Tian; Chen, Jaw-Chyun; Hsu, Shu-Chun; Chung, Jing-Gung

    2015-01-01

    Numerous evidences have shown that plant flavonoids (naturally occurring substances) have been reported to have chemopreventive activities and protect against experimental carcinogenesis. Kaempferol, one of the flavonoids, is widely distributed in fruits and vegetables, and may have cancer chemopreventive properties. However, the precise underlying mechanism regarding induced DNA damage and suppressed DNA repair system are poorly understood. In this study, we investigated whether kaempferol induced DNA damage and affected DNA repair associated protein expression in human leukemia HL-60 cells in vitro. Percentages of viable cells were measured via a flow cytometry assay. DNA damage was examined by Comet assay and DAPI staining. DNA fragmentation (ladder) was examined by DNA gel electrophoresis. The changes of protein levels associated with DNA repair were examined by Western blotting. Results showed that kaempferol dose-dependently decreased the viable cells. Comet assay indicated that kaempferol induced DNA damage (Comet tail) in a dose-dependent manner and DAPI staining also showed increased doses of kaempferol which led to increased DNA condensation, these effects are all of dose-dependent manners. Western blotting indicated that kaempferol-decreased protein expression associated with DNA repair system, such as phosphate-ataxia-telangiectasia mutated (p-ATM), phosphate-ataxia-telangiectasia and Rad3-related (p-ATR), 14-3-3 proteins sigma (14-3-3σ), DNA-dependent serine/threonine protein kinase (DNA-PK), O(6)-methylguanine-DNA methyltransferase (MGMT), p53 and MDC1 protein expressions, but increased the protein expression of p-p53 and p-H2AX. Protein translocation was examined by confocal laser microscopy, and we found that kaempferol increased the levels of p-H2AX and p-p53 in HL-60 cells. Taken together, in the present study, we found that kaempferol induced DNA damage and suppressed DNA repair and inhibited DNA repair associated protein expression in HL-60

  2. Evidence for repair of ultraviolet light-damaged herpes virus in human fibroblasts by a recombination mechanism

    Energy Technology Data Exchange (ETDEWEB)

    Hall, J.D.; Featherston, J.D.; Almy, R.E.

    1980-09-01

    Human cells were either singly or multiply infected with herpes simplex virus (HSV-1) damaged by ultraviolet (uv) light, and the fraction of cells able to produce infectious virus was measured. The fraction of virus-producing cells was considerably greater for multiply infected cells than for singly infected cells at each uv dose examined. These high survival levels of uv-irradiated virus in multiply infected cells demonstrated that multiplicity-dependent repair, possibly due to genetic exchanges between damaged HSV-1 genomes, was occurring in these cells. To test whether uv light is recombinogenic for HSV-1, the effect of uv irradiation on the yield of temperature-resistant viral recombinants in cells infected with pairs of temperature-sensitive mutants was also investigated. The results of these experiments showed that the defective functions in these mutant host cells are not required for multiplicity-dependent repair or uv-stimulated viral recombination in herpes-infected cells.

  3. Association between DNA damage response and repair genes and risk of invasive serous ovarian cancer.

    Directory of Open Access Journals (Sweden)

    Joellen M Schildkraut

    Full Text Available BACKGROUND: We analyzed the association between 53 genes related to DNA repair and p53-mediated damage response and serous ovarian cancer risk using case-control data from the North Carolina Ovarian Cancer Study (NCOCS, a population-based, case-control study. METHODS/PRINCIPAL FINDINGS: The analysis was restricted to 364 invasive serous ovarian cancer cases and 761 controls of white, non-Hispanic race. Statistical analysis was two staged: a screen using marginal Bayes factors (BFs for 484 SNPs and a modeling stage in which we calculated multivariate adjusted posterior probabilities of association for 77 SNPs that passed the screen. These probabilities were conditional on subject age at diagnosis/interview, batch, a DNA quality metric and genotypes of other SNPs and allowed for uncertainty in the genetic parameterizations of the SNPs and number of associated SNPs. Six SNPs had Bayes factors greater than 10 in favor of an association with invasive serous ovarian cancer. These included rs5762746 (median OR(odds ratio(per allele = 0.66; 95% credible interval (CI = 0.44-1.00 and rs6005835 (median OR(per allele = 0.69; 95% CI = 0.53-0.91 in CHEK2, rs2078486 (median OR(per allele = 1.65; 95% CI = 1.21-2.25 and rs12951053 (median OR(per allele = 1.65; 95% CI = 1.20-2.26 in TP53, rs411697 (median OR (rare homozygote = 0.53; 95% CI = 0.35 - 0.79 in BACH1 and rs10131 (median OR( rare homozygote = not estimable in LIG4. The six most highly associated SNPs are either predicted to be functionally significant or are in LD with such a variant. The variants in TP53 were confirmed to be associated in a large follow-up study. CONCLUSIONS/SIGNIFICANCE: Based on our findings, further follow-up of the DNA repair and response pathways in a larger dataset is warranted to confirm these results.

  4. DNA repair and damage pathway related cancer suppressor genes in low-dose-rate irradiated AKR/J an IR mice

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Hyun Soon; Bong, Jin Jong; Kang, Yumi; Choi, Moo Hyun; Lee, Hae Un; Yoo, Jae Young; Choi, Seung Jin; Kim, Hee Sun [Radiation Health Research Institute, Korea Hydro and Nuclear Power Co., Ltd, Gyeongju (Korea, Republic of); Lee, Kyung Mi [Global Research Lab, BAERI Institute, Dept. of Biochemistry and Molecular Biology, Korea University College of Medicine, Seoul (Korea, Republic of)

    2012-11-15

    It has been reported that low-dose-rate radiation stimulates the immune response, prolongs life span and inhibits carcinogenesis. The high dose-rate radiation influences the expression of DNA repair and damage-related genes. In contrast, DNA repair and damage signaling triggered by low-dose-rate irradiation remain unclear. In the present study, we investigated the differential expression of DNA repair and damage pathway related genes in the thymus of AKR/J and ICR mice after 100th day low-dose-rate irradiation. Our findings demonstrated that low-dose-rate γ -radiation suppressed tumorigenesis.

  5. Neurons efficiently repair glutamate-induced oxidative DNA damage by a process involving CREB-mediated up-regulation of apurinic endonuclease 1

    DEFF Research Database (Denmark)

    Yang, Jenq-Lin; Tadokoro, Takashi; Keijzers, Guido

    2010-01-01

    damage after glutamate treatment, suggesting that APE1 is a key repair protein for glutamate-induced DNA damage. A cAMP-response element-binding protein (CREB) binding sequence is present in the Ape1 gene (encodes APE1 protein) promoter and treatment of neurons with a Ca(2+)/calmodulin-dependent kinase......-mediated DNA damage that is then rapidly repaired by a mechanism involving Ca(2+)-induced, CREB-mediated APE1 expression. Our findings reveal a previously unknown ability of neurons to efficiently repair oxidative DNA lesions after transient activation of glutamate receptors....

  6. Lung Basal Stem Cells Rapidly Repair DNA Damage Using the Error-Prone Nonhomologous End-Joining Pathway.

    Science.gov (United States)

    Weeden, Clare E; Chen, Yunshun; Ma, Stephen B; Hu, Yifang; Ramm, Georg; Sutherland, Kate D; Smyth, Gordon K; Asselin-Labat, Marie-Liesse

    2017-01-01

    Lung squamous cell carcinoma (SqCC), the second most common subtype of lung cancer, is strongly associated with tobacco smoking and exhibits genomic instability. The cellular origins and molecular processes that contribute to SqCC formation are largely unexplored. Here we show that human basal stem cells (BSCs) isolated from heavy smokers proliferate extensively, whereas their alveolar progenitor cell counterparts have limited colony-forming capacity. We demonstrate that this difference arises in part because of the ability of BSCs to repair their DNA more efficiently than alveolar cells following ionizing radiation or chemical-induced DNA damage. Analysis of mice harbouring a mutation in the DNA-dependent protein kinase catalytic subunit (DNA-PKcs), a key enzyme in DNA damage repair by nonhomologous end joining (NHEJ), indicated that BSCs preferentially repair their DNA by this error-prone process. Interestingly, polyploidy, a phenomenon associated with genetically unstable cells, was only observed in the human BSC subset. Expression signature analysis indicated that BSCs are the likely cells of origin of human SqCC and that high levels of NHEJ genes in SqCC are correlated with increasing genomic instability. Hence, our results favour a model in which heavy smoking promotes proliferation of BSCs, and their predilection for error-prone NHEJ could lead to the high mutagenic burden that culminates in SqCC. Targeting DNA repair processes may therefore have a role in the prevention and therapy of SqCC.

  7. Preventing damage limitation: targeting DNA-PKcs and DNA double strand break repair pathways for ovarian cancer therapy

    Directory of Open Access Journals (Sweden)

    Daniela A Dungl

    2015-10-01

    Full Text Available Platinum-based chemotherapy is the cornerstone of ovarian cancer treatment, and its efficacy is dependent on the generation of DNA damage, with subsequent induction of apoptosis. Inappropriate or aberrant activation of the DNA damage response network is are associated with resistance to platinum, and defects in DNA repair pathways play critical roles in determining patient response to chemotherapy. In ovarian cancer, tumour cell defects in homologous recombination - a repair pathway activated in response to DNA double strand breaks (DSB - are most commonly associated with platinum sensitive disease. However, despite initial sensitivity, the emergence of resistance is frequent. Here, we review strategies for directly interfering with DNA repair pathways, with particular focus on direct inhibition of non-homologous end joining (NHEJ, another DSB repair pathway. DNA-PKcs is a core component of NHEJ and it has shown considerable promise as a chemosensitization target in numerous cancer types, including ovarian cancer where it functions to promote platinum-induced survival signalling, via AKT activation. The development of pharmacological inhibitors of DNA-PKcs is on-going, and clinic-ready agents offer real hope to patients with chemoresistant disease.

  8. Femoral hernia repair

    Science.gov (United States)

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

  9. Oxidative Damage to Lung Tissue and Peripheral Blood in Endotracheal PM2.5-treated Rats

    Institute of Scientific and Technical Information of China (English)

    ZHI-QING LIN; ZHU-GE XI; DAN-FENG YANG; FU-HUAN CHAO; HUA-SHAN ZHANG; WEI ZHANG; HUANG-LIANG LIU; ZAI-MING YANG; RU-BAO SUN

    2009-01-01

    Objective To investigate the oxidative damage to lung tissue and peripherial blood in PM2.5-treated rats.Methods PM2.5 samples were collected using an auto-sampling instrument in summer and winter.Treated samples were endotracheally instilled into rats.Activity of reduced glutathione peroxidase (GSH-Px) and concentration of malondialdehyde (MDA) were used as oxidative damage biomarkers of lung tissue and peripheral blood detected with the biochemical method.DNA migration length (μm) and rate of tail were used as DNA damage biomarkers of lung tissue and peripheral blood detected with the biochemical method. Results The activity of GSH-Px and the concentration of MDA in lung tissue significantly decreased after exposure to PM2.5 for 7-14 days.In peripheral blood,the concentration of MDA decreased,but the activity of GSH-Px increased 7 and 14 days after experiments.The two indicators had a dose-effect relation and similar changing tendency in lung tissue and peripheral blood.The DNA migration length (μm) and rate of tail in lung tissue and peripheral blood significantly increased 7 and 14 days after exposure to PM2.5.The two indicators had a dose-effect relation and similar changing tendency in lung tissue and peripheral blood. Conclusion PM2.5 has a definite oxidative effect on lung tissue and peripheral blood.The activity of GSH-Px and the concentration of MDA are valuable biomarkers of oxidative lung tissue damage induced by PM2.5.The DNA migration length (μm) and rate of tail are simple and valuable biomarkers of PM2.5-induced DNA damage in lung tissues and peripheral blood.The degree of DNA damage in peripheral blood can predict the degree of DNA damage in lung tissue.

  10. Aircraft Battle Damage Repair (ABDR) 2000: Will ABDR Become the Logistics Center of Gravity by the Year 2000

    Science.gov (United States)

    1989-05-01

    damage repair comes from the conflict in Southeast Asia CSEA ) and data available from the Arab-Israeli 1973 Yom Kippur war. Battle damage experience data...Performance." Air Force Journal of Loglutics, Vol. VIII, No. 4. Fall 1984, p. 9. 3. Department of the A~r Forcei Headquarters U.S. Air Force. "R&M 2000...Key to Combat Strength." 1.jr Force Journal of Logistl, Winter 1988, pp. 5-6. 17. Kitfield, James. "Concern Over Composites." ° Forum, January-February

  11. Excision repair of UV radiation-induced DNA damage in Caenorhabditis elegans

    Energy Technology Data Exchange (ETDEWEB)

    Hartman, P.S.; Hevelone, J.; Dwarakanath, V.; Mitchell, D.L. (Texas Christian Univ., Fort Worth (USA))

    1989-06-01

    Radioimmunoassays were used to monitor the removal of antibody-binding sites associated with the two major UV radiation-induced DNA photoproducts (cyclobutane dimers and (6-4) photoproducts). Unlike with cultured human cells, where (6-4) photoproducts are removed more rapidly than cyclobutane dimers, the kinetics of repair were similar for both lesions. Repair capacity in wild type diminished throughout development. The radioimmunoassays were also employed to confirm the absence of photoreactivation in C. elegans. In addition, three radiation-sensitive mutants (rad-1, rad-2, rad-7) displayed normal repair capacities. An excision defect was much more pronounced in larvae than embryos in the fourth mutant tested (rad-3). This correlates with the hypersensitivity pattern of this mutant and suggests that DNA repair may be developmentally regulated in C. elegans. The mechanism of DNA repair in C. elegans as well as the relationship between the repair of specific photoproducts and UV radiation sensitivity during development are discussed.

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

    Science.gov (United States)

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

    2004-12-17

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

  13. Gypenosides causes DNA damage and inhibits expression of DNA repair genes of human oral cancer SAS cells.

    Science.gov (United States)

    Lu, Kung-Wen; Chen, Jung-Chou; Lai, Tung-Yuan; Yang, Jai-Sing; Weng, Shu-Wen; Ma, Yi-Shih; Tang, Nou-Ying; Lu, Pei-Jung; Weng, Jing-Ru; Chung, Jing-Gung

    2010-01-01

    Gypenosides (Gyp) are the major components of Gynostemma pentaphyllum Makino, a Chinese medical plant. Recently, Gyp has been shown to induce cell cycle arrest and apoptosis in many human cancer cell lines. However, there is no available information to address the effects of Gyp on DNA damage and DNA repair-associated gene expression in human oral cancer cells. Therefore, we investigated whether Gyp induced DNA damage and DNA repair gene expression in human oral cancer SAS cells. The results from flow cytometric assay indicated that Gyp-induced cytotoxic effects led to a decrease in the percentage of viable SAS cells. The results from comet assay revealed that the incubation of SAS cells with Gyp led to a longer DNA migration smear (comet tail) when compared with control and this effect was dose-dependent. The results from real-time PCR analysis indicated that treatment of SAS cells with 180 mug/ml of Gyp for 24 h led to a decrease in 14-3-3sigma, DNA-dependent serine/threonine protein kinase (DNAPK), p53, ataxia telangiectasia mutated (ATM), ataxia-telangiectasia and Rad3-related (ATR) and breast cancer gene 1 (BRCA1) mRNA expression. These observations may explain the cell death caused by Gyp in SAS cells. Taken together, Gyp induced DNA damage and inhibited DNA repair-associated gene expressions in human oral cancer SAS cells in vitro.

  14. Nerve autografts and tissue-engineered materials for the repair of peripheral nerve injuries: a 5-year bibliometric analysis

    Directory of Open Access Journals (Sweden)

    Yuan Gao

    2015-01-01

    Full Text Available With advances in biomedical methods, tissue-engineered materials have developed rapidly as an alternative to nerve autografts for the repair of peripheral nerve injuries. However, the materials selected for use in the repair of peripheral nerve injuries, in particular multiple injuries and large-gap defects, must be chosen carefully. Various methods and materials for protecting the healthy tissue and repairing peripheral nerve injuries have been described, and each method or material has advantages and disadvantages. Recently, a large amount of research has been focused on tissue-engineered materials for the repair of peripheral nerve injuries. Using the keywords "pe-ripheral nerve injury", "autotransplant", "nerve graft", and "biomaterial", we retrieved publications using tissue-engineered materials for the repair of peripheral nerve injuries appearing in the Web of Science from 2010 to 2014. The country with the most total publications was the USA. The institutions that were the most productive in this field include Hannover Medical School (Germany, Washington University (USA, and Nantong University (China. The total number of publications using tissue-engineered materials for the repair of peripheral nerve injuries grad-ually increased over time, as did the number of Chinese publications, suggesting that China has made many scientific contributions to this field of research.

  15. Tendon repair

    Science.gov (United States)

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

  16. Nanoscale Surface Modifications of Medical Implants for Cartilage Tissue Repair and Regeneration

    Science.gov (United States)

    Griffin, MF; Szarko, M; Seifailan, A; Butler, PE

    2016-01-01

    Background: Natural cartilage regeneration is limited after trauma or degenerative processes. Due to the clinical challenge of reconstruction of articular cartilage, research into developing biomaterials to support cartilage regeneration have evolved. The structural architecture of composition of the cartilage extracellular matrix (ECM) is vital in guiding cell adhesion, migration and formation of cartilage. Current technologies have tried to mimic the cell’s nanoscale microenvironment to improve implants to improve cartilage tissue repair. Methods: This review evaluates nanoscale techniques used to modify the implant surface for cartilage regeneration. Results: The surface of biomaterial is a vital parameter to guide cell adhesion and consequently allow for the formation of ECM and allow for tissue repair. By providing nanosized cues on the surface in the form of a nanotopography or nanosized molecules, allows for better control of cell behaviour and regeneration of cartilage. Chemical, physical and lithography techniques have all been explored for modifying the nanoscale surface of implants to promote chondrocyte adhesion and ECM formation. Conclusion: Future studies are needed to further establish the optimal nanoscale modification of implants for cartilage tissue regeneration. PMID:28217208

  17. A biocompatible hybrid material with simultaneous calcium and strontium release capability for bone tissue repair

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, J. Carlos [CICECO — Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Wacha, András [Research Centre for Natural Sciences, Hungarian Academy of Sciences, Magyar Tudósok körútja 2, Budapest 1117 (Hungary); Gomes, Pedro S. [Laboratory for Bone Metabolism and Regeneration, Faculdade de Medicina Dentária, Universidade do Porto (Portugal); Alves, Luís C. [C2TN, Instituto Superior Técnico, Universidade de Lisboa, E.N.10, 2695-066 Bobadela LRS (Portugal); Fernandes, M. Helena Vaz [CICECO — Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Salvado, Isabel M. Miranda, E-mail: isabelmsalvado@ua.pt [CICECO — Aveiro Institute of Materials, Department of Materials and Ceramic Engineering, University of Aveiro, 3810-193 Aveiro (Portugal); Fernandes, M. Helena R. [Laboratory for Bone Metabolism and Regeneration, Faculdade de Medicina Dentária, Universidade do Porto (Portugal)

    2016-05-01

    The increasing interest in the effect of strontium in bone tissue repair has promoted the development of bioactive materials with strontium release capability. According to literature, hybrid materials based on the system PDMS–SiO{sub 2} have been considered a plausible alternative as they present a mechanical behavior similar to the one of the human bone. The main purpose of this study was to obtain a biocompatible hybrid material with simultaneous calcium and strontium release capability. A hybrid material, in the system PDMS–SiO{sub 2}–CaO–SrO, was prepared with the incorporation of 0.05 mol of titanium per mol of SiO{sub 2}. Calcium and strontium were added using the respective acetates as sources, following a sol–gel technique previously developed by the present authors. The obtained samples were characterized by FT-IR, solid-state NMR, and SAXS, and surface roughness was analyzed by 3D optical profilometry. In vitro studies were performed by immersion of the samples in Kokubo's SBF for different periods of time, in order to determine the bioactive potential of these hybrids. Surfaces of the immersed samples were observed by SEM, EDS and PIXE, showing the formation of calcium phosphate precipitates. Supernatants were analyzed by ICP, revealing the capability of the material to simultaneously fix phosphorus ions and to release calcium and strontium, in a concentration range within the values reported as suitable for the induction of the bone tissue repair. The material demonstrated to be cytocompatible when tested with MG63 osteoblastic cells, exhibiting an inductive effect on cell proliferation and alkaline phosphatase activity. - Highlights: • A hybrid PDMS–SiO{sub 2}–CaO–SrO material was prepared with the incorporation of Ti. • Sr was released in concentrations suitable for the induction of bone tissue repair. • The material demonstrated to be cytocompatible when tested with osteoblastic cells.

  18. Role of endogenous Schwann cells in tissue repair after spinal cord injury

    Institute of Scientific and Technical Information of China (English)

    Shu-xin Zhang; Fengfa Huang; Mary Gates; Eric G. Holmberg

    2013-01-01

    Schwann cells are glial cells of peripheral nervous system, responsible for axonal myelination and ensheathing, as well as tissue repair following a peripheral nervous system injury. They are one of several cell types that are widely studied and most commonly used for cell transplantation to treat spinal cord injury, due to their intrinsic characteristics including the ability to secrete a variety of neurotrophic factors. This mini review summarizes the recent findings of endogenous Schwann cells after spinal cord injury and discusses their role in tissue repair and axonal regeneration. After spinal cord injury, numerous endogenous Schwann cells migrate into the lesion site from the nerve roots, involving in the construction of newly formed repaired tissue and axonal myelination. These invading Schwann cells also can move a long distance away from the injury site both rostrally and caudally. In addition, Schwann cells can be induced to migrate by minimal insults (such as scar ablation) within the spinal cord and integrate with astrocytes under certain circumstances. More importantly, the host Schwann cells can be induced to migrate into spinal cord by transplantation of different cell types, such as exogenous Schwann cells, olfactory ensheathing cells, and bone marrow-derived stromal stem cells. Migration of endogenous Schwann cells following spinal cord injury is a common natural phenomenon found both in animal and human, and the myelination by Schwann cells has been examined effective in signal conduction electrophysiologically. Therefore, if the inherent properties of endogenous Schwann cells could be developed and utilized, it would offer a new avenue for the restoration of injured spinal cord.

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

    Science.gov (United States)

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

    2015-03-01

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

  20. DNA Damage and Repair Biomarkers in Cervical Cancer Patients Treated with Neoadjuvant Chemotherapy: An Exploratory Analysis.

    Directory of Open Access Journals (Sweden)

    Patrizia Vici

    Full Text Available Cervical cancer cells commonly harbour a defective G1/S checkpoint owing to the interaction of viral oncoproteins with p53 and retinoblastoma protein. The activation of the G2/M checkpoint may thus become essential for protecting cancer cells from genotoxic insults, such as chemotherapy. In 52 cervical cancer patients treated with neoadjuvant chemotherapy, we investigated whether the levels of phosphorylated Wee1 (pWee1, a key G2/M checkpoint kinase, and γ-H2AX, a marker of DNA double-strand breaks, discriminated between patients with a pathological complete response (pCR and those with residual disease. We also tested the association between pWee1 and phosphorylated Chk1 (pChk1, a kinase acting upstream Wee1 in the G2/M checkpoint pathway. pWee1, γ-H2AX and pChk1 were retrospectively assessed in diagnostic biopsies by immunohistochemistry. The degrees of pWee1 and pChk1 expression were defined using three different classification methods, i.e., staining intensity, Allred score, and a multiplicative score. γ-H2AX was analyzed both as continuous and categorical variable. Irrespective of the classification used, elevated levels of pWee1 and γ-H2AX were significantly associated with a lower rate of pCR. In univariate and multivariate analyses, pWee1 and γ-H2AX were both associated with reduced pCR. Internal validation conducted through a re-sampling without replacement procedure confirmed the robustness of the multivariate model. Finally, we found a significant association between pWee1 and pChk1. The message conveyed by the present analysis is that biomarkers of DNA damage and repair may predict the efficacy of neoadjuvant chemotherapy in cervical cancer. Further studies are warranted to prospectively validate these encouraging findings.

  1. Repair of traumatic plasmalemmal damage to neurons and other eukar yotic cells

    Institute of Scientific and Technical Information of China (English)

    George D. Bittner; Christopher S. Spaeth§; Andrew D. Poon; Zachary S. Burgess; Christopher H. McGill

    2016-01-01

    The repair (sealing) of plasmalemmal damage, consisting of small holes to complete transections, is criti-cal for cell survival, especially for neurons that rarely regenerate cell bodies. We ifrst describe and evaluate different measures of cell sealing. Some measures, including morphological/ultra-structural observations, membrane potential, and input resistance, provide very ambiguous assessments of plasmalemmal sealing. In contrast, measures of ionic current lfow and dye barriers can, if appropriately used, provide more ac-curate assessments. We describe the effects of various substances (calcium, calpains, cytoskeletal proteins, ESCRT proteins, mUNC-13, NSF, PEG) and biochemical pathways (PKA, PKC, PLC, Epac, cytosolic ox-idation) on plasmalemmal sealing probability, and suggest that substances, pathways, and cellular events associated with plasmalemmal sealing have undergone a very conservative evolution. During sealing, calcium ion inlfux mobilizes vesicles and other membranous structures (lysosomes, mitochondria, etc.) in a continuous fashion to form a vesicular plug that gradually restricts diffusion of increasingly smaller molecules and ions over a period of seconds to minutes. Furthermore, we find no direct evidence that sealing occurs through the collapse and fusion of severed plasmalemmal lealfets, or in a single step involv-ing the fusion of one large wound vesicle with the nearby, undamaged plasmalemma. We describe how increases in perikaryal calcium levels following axonal transection account for observations that cell body survival decreases the closer an axon is transected to the perikaryon. Finally, we speculate on relationships between plasmalemmal sealing, Wallerian degeneration, and the ability of polyethylene glycol (PEG) to seal cell membranes and rejoin severed axonal ends–an important consideration for the future treatment of trauma to peripheral nerves. A better knowledge of biochemical pathways and cytoplasmic structures in-volved in

  2. Repair of traumatic plasmalemmal damage to neurons and other eukaryotic cells

    Directory of Open Access Journals (Sweden)

    George D Bittner

    2016-01-01

    Full Text Available The repair (sealing of plasmalemmal damage, consisting of small holes to complete transections, is critical for cell survival, especially for neurons that rarely regenerate cell bodies. We first describe and evaluate different measures of cell sealing. Some measures, including morphological/ultra-structural observations, membrane potential, and input resistance, provide very ambiguous assessments of plasmalemmal sealing. In contrast, measures of ionic current flow and dye barriers can, if appropriately used, provide more accurate assessments. We describe the effects of various substances (calcium, calpains, cytoskeletal proteins, ESCRT proteins, mUNC-13, NSF, PEG and biochemical pathways (PKA, PKC, PLC, Epac, cytosolic oxidation on plasmalemmal sealing probability, and suggest that substances, pathways, and cellular events associated with plasmalemmal sealing have undergone a very conservative evolution. During sealing, calcium ion influx mobilizes vesicles and other membranous structures (lysosomes, mitochondria, etc. in a continuous fashion to form a vesicular plug that gradually restricts diffusion of increasingly smaller molecules and ions over a period of seconds to minutes. Furthermore, we find no direct evidence that sealing occurs through the collapse and fusion of severed plasmalemmal leaflets, or in a single step involving the fusion of one large wound vesicle with the nearby, undamaged plasmalemma. We describe how increases in perikaryal calcium levels following axonal transection account for observations that cell body survival decreases the closer an axon is transected to the perikaryon. Finally, we speculate on relationships between plasmalemmal sealing, Wallerian degeneration, and the ability of polyethylene glycol (PEG to seal cell membranes and rejoin severed axonal ends – an important consideration for the future treatment of trauma to peripheral nerves. A better knowledge of biochemical pathways and cytoplasmic structures

  3. Cyclobutane pyrimidine dimers photolyase from extremophilic microalga: Remarkable UVB resistance and efficient DNA damage repair

    Energy Technology Data Exchange (ETDEWEB)

    Li, Chongjie [Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061 (China); Ma, Li [Key Laboratory of Biofuels, and Shandong Provincial Key Laboratory of Energy Genetics, Qingdao Institute of Bioenergy and Bioprocess Technology, Chinese Academy of Sciences, Qingdao 266101 (China); Mou, Shanli [Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao (China); Wang, Yibin, E-mail: wangyibin@fio.org.cn [Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061 (China); Zheng, Zhou; Liu, Fangming; Qi, Xiaoqing; An, Meiling; Chen, Hao [Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061 (China); Miao, Jinlai, E-mail: miaojinlai@163.com [Key Laboratory of Marine Bioactive Substance, The First Institute of Oceanography, State Oceanic Administration, Qingdao 266061 (China); State Key Laboratory of Biological Fermentation Engineering of Beer (In Preparation), Qingdao (China)

    2015-03-15

    Highlights: • Chlamydomonas sp. ICE-L photolyase gene PHR2 is first cloned and expressed in E. coli. • PHR2 complemented E. coli could efficiently survival from UV radiation. • Expressed PHR2 photolyase has distinct photo-reactivation activity in vitro. - Abstract: Bacteria living in the Antarctic region have developed several adaptive features for growth and survival under extreme conditions. Chlamydomonas sp. ICE-Lis well adapted to high levels of solar UV radiation. A putative photolyase was identified in the Chlamydomonas sp. ICE-L transcriptome. The complete cDNA sequence was obtained by RACE-PCR. This PHR encoding includes a polypeptide of 579 amino acids with clear photolyase signatures belonging to class II CPD-photolyases, sharing a high degree of homology with Chlamydomonas reinhardtii (68%). Real-time PCR was performed to investigate the potential DNA damage and responses following UVB exposure. CPD photolyase mRNA expression level increased over 50-fold in response to UVB radiation for 6 h. Using photolyase complementation assay, we demonstrated that DNA photolyase increased photo-repair more than 116-fold in Escherichia coli strain SY2 under 100 μw/cm{sup 2} UVB radiation. To determine whether photolyase is active in vitro, CPD photolyase was over-expressed. It was shown that pyrimidine dimers were split by the action of PHR2. This study reports the unique structure and high activity of the enzyme. These findings are relevant for further understanding of molecular mechanisms of photo-reactivation, and will accelerate the utilization of photolyase in the medical field.

  4. Cell-based tissue engineering strategies used in the clinical repair of articular cartilage

    Science.gov (United States)

    Huang, Brian J.; Hu, Jerry C.; Athanasiou, Kyriacos A.

    2016-01-01

    One of the most important issues facing cartilage tissue engineering is the inability to move technologies into the clinic. Despite the multitude of review articles on the paradigm of biomaterials, signals, and cells, it is reported that 90% of new drugs that advance past animal studies fail clinical trials (1). The intent of this review is to provide readers with an understanding of the scientific details of tissue engineered cartilage products that have demonstrated a certain level of efficacy in humans, so that newer technologies may be developed upon this foundation. Compared to existing treatments, such as microfracture or autologous chondrocyte implantation, a tissue engineered product can potentially provide more consistent clinical results in forming hyaline repair tissue and in filling the entirety of the defect. The various tissue engineering strategies (e.g., cell expansion, scaffold material, media formulations, biomimetic stimuli, etc.) used in forming these products, as collected from published literature, company websites, and relevant patents, are critically discussed. The authors note that many details about these products remain proprietary, not all information is made public, and that advancements to the products are continuously made. Nevertheless, by fully understanding the design and production processes of these emerging technologies, one can gain tremendous insight into how to best use them and also how to design the next generation of tissue engineered cartilage products. PMID:27177218

  5. Repair of Sheep Metatarsus Defects by Using Tissue-engineering Technique

    Institute of Scientific and Technical Information of China (English)

    LI Zhanghua; YANG Yi; WANG Changyong; XIA Renyun; ZHANG Yufu; ZHAO Qiang; LIAO Wen; WANG Yonghong; LU Jianxi

    2005-01-01

    Tissue-engineering bone with porous β-tricalcium phosphate (β-TCP) ceramic and autologous bone marrow mesenchymal stem cells (MSC) was constructed and the effect of this composite on healing of segmental bone defects was investigated. 10-15 ml bone marrow aspirates were harvested from the iliac crestof sheep, and enriched for MSC by density gradient centrifugation over a Percoll cushion (1. 073 g/ml). After cultured and proliferated, tissue-engineering bones were constructed with these cells seeded onto porous β-TCP, and then the constructs were implanted in 8 sheep left metatarsus defect (25 mm in length) as experimental group. Porous β-TCP only were implanted to bridge same size and position defects in 8 sheep as control group, and 25 mm segmental bone defects of left metatarsus were left empty in 4 sheep as blank group. Sheep were sacrificed on the 6th, 12th, and 24th week postoperatively and the implants samples were examined by radiograph, histology, and biomechanical test. The 4 sheep in blank group were sacrificed on the 24th week postoperatively. The results showed that new bone tissues were observed either radiographic or histologically at the defects of experimental group as early as 6th week postoperatively, but not in control group, and osteoid tissue, woven bone and lamellar bone occurred earlier than in control group in which the bone defects were repaired in "creep substitution" way, because of the new bone formed in direct manner without progression through a cartilaginous intermediate. At the 24th week, radiographs and biomechanical test revealed an almost complete repair of the defect of experimental group, only partly in control group. The bone defects in blank group were non-healing at the 24th week. It was concluded that engineering bones constructed with porous β-TCP and autologous MSC were capable of repairing segmental bone defects in sheep metatarsus beyond "creep substitution" way and making it healed earlier. Porous β-TCP being

  6. Contributions of DNA repair and damage response pathways to the non-linear genotoxic responses of alkylating agents

    Science.gov (United States)

    Klapacz, Joanna; Pottenger, Lynn H.; Engelward, Bevin P.; Heinen, Christopher D.; Johnson, George E.; Clewell, Rebecca A.; Carmichael, Paul L.; Adeleye, Yeyejide; Andersen, Melvin E.

    2016-01-01

    From a risk assessment perspective, DNA-reactive agents are conventionally assumed to have genotoxic risks at all exposure levels, thus applying a linear extrapolation for low-dose responses. New approaches discussed here, including more diverse and sensitive methods for assessing DNA damage and DNA repair, strongly support the existence of measurable regions where genotoxic responses with increasing doses are insignificant relative to control. Model monofunctional alkylating agents have in vitro and in vivo datasets amenable to determination of points of departure (PoDs) for genotoxic effects. A session at the 2013 Society of Toxicology meeting provided an opportunity to survey the progress in understanding the biological basis of empirically-observed PoDs for DNA alkylating agents. Together with the literature published since, this review discusses cellular pathways activated by endogenous and exogenous alkylation DNA damage. Cells have evolved conserved processes that monitor and counteract a spontaneous steady-state level of DNA damage. The ubiquitous network of DNA repair pathways serves as the first line of defense for clearing of the DNA damage and preventing mutation. Other biological pathways discussed here that are activated by genotoxic stress include post-translational activation of cell cycle networks and transcriptional networks for apoptosis/cell death. The interactions of various DNA repair and DNA damage response pathways provide biological bases for the observed PoD behaviors seen with genotoxic compounds. Thus, after formation of DNA adducts, the activation of cellular pathways can lead to the avoidance a mutagenic outcome. The understanding of the cellular mechanisms acting within the low-dose region will serve to better characterize risks from exposures to DNA-reactive agents at environmentally-relevant concentrations. PMID:27036068

  7. The effect of tissue surface modification with collagenase and addition of TGF-beta 3 on the healing potential of meniscal tears repaired with tissue glues in vitro

    NARCIS (Netherlands)

    Bochynska, Agnieszka Izabela; Hannink, Gerjon; Verhoeven, Renate; Grijpma, Dirk W.; Buma, Pieter

    The aim of the current in vitro study was to investigate if tissue surface modification with collagenase and addition of the TGF-beta 3 can increase the number of cells present in meniscus tears repaired with the use of newly developed tissue adhesives based on isocyanate-terminated block

  8. Damage induced by pulsed IR laser radiation at transitions between different tissues

    Science.gov (United States)

    Frenz, Martin; Greber, Charlotte M.; Romano, Valerio; Forrer, Martin; Weber, Heinz P.

    1991-06-01

    Due to their strong absorption in water IR-lasers are excellent sources for precision cutting with minimal thermal damage in various fields of medicine. To understand the laser tissue interaction process one has to take into account the liquefaction of target material at the region of radiation impact. The dynamics of the created liquid may cause unexpected and undesirable effects for surgical laser applications. We studied the thermal damage along the walls of incision craters in terms of the elastic material properties and the dynamics of the drilling process. We show that the extension of thermally altered tissue is strongly influenced by the amount of hot liquefied tissue material remaining in the crater. When drilling into mechanically homogeneous materials this amount is essentially determined by the laser intensity used. However, when drilling through a composite structure consisting of various tissue types with different material properties, this is no longer the case. Even at low intensities, the damage zone varies substantially between the different layers. In our investigations we compared histologically and ultrastructurally the instantaneously created damage in the connective tissue and the subjacent skeletal muscle of skin after laser cutting, with long-time heating injuries. This comparison allows a differentiation between thermal and mechanical damage and an estimation of the minimum temperature created in the crater during the laser impact. The light microscopical examinations shows that the thermal damage in the connective tissue is about three times smaller than in the subjacent muscle layer. Comparative studies made with a composite structure consisting of the tissue substitutes gelatin and agar reveal that the unexpectedly large damage in the skeletal muscle layer is a result of the abrupt change of the elastic properties at the material transition. This discontinuity changes the ejection dynamics leading to a confinement of hot liquefied

  9. Induction and regulation of crown dentinogenesis: embryonic events as a template for dental tissue repair?

    Science.gov (United States)

    Smith, A J; Lesot, H

    2001-01-01

    Close regulation of odontoblast differentiation and subsequent secretory activity is critical for dentinogenesis during both embryogenesis and tissue repair. Some dental papilla cells achieve commitment and specific competence, allowing them to respond to epithelially derived inductive signals during the process of odontoblast differentiation. Temporo-spatial regulation of odontoblast differentiation is dependent on matrix-mediated interactions involving the basement membrane (BM). Experimental studies have highlighted the possible roles of growth factors in these processes. Regulation of functional activity of odontoblasts allows for both ordered secretion of the primary dentin matrix and maintenance of vitality and down-regulation of secretory activity throughout secondary dentinogenesis. After injury to the mature tooth, the fate of the odontoblast can vary according to the intensity of the injury. Milder injury can result in up-regulation of functional activity leading to focal secretion of a reactionary dentin matrix, while greater injury can lead to odontoblast cell death. Induction of differentiation of a new generation of odontoblast-like cells can then lead to reparative dentinogenesis. Many similarities exist between development and repair, including matrix-mediation of the cellular processes and the apparent involvement of growth factors as signaling molecules despite the absence of epithelium during repair. While some of the molecular mediators appear to be common to these processes, the close regulation of primary dentinogenesis may be less ordered during tertiary dentinogenic responses.

  10. Collagen insulated from tensile damage by domains that unfold reversibly: in situ X-ray investigation of mechanical yield and damage repair in the mussel byssus.

    Science.gov (United States)

    Harrington, Matthew J; Gupta, Himadri S; Fratzl, Peter; Waite, J Herbert

    2009-07-01

    The byssal threads of the California mussel, Mytilus californianus, are highly hysteretic, elastomeric fibers that collectively perform a holdfast function in wave-swept rocky seashore habitats. Following cyclic loading past the mechanical yield point, threads exhibit a damage-dependent reduction in mechanical performance. However, the distal portion of the byssal thread is capable of recovering initial material properties through a time-dependent healing process in the absence of active cellular metabolism. Byssal threads are composed almost exclusively of multi-domain hybrid collagens known as preCols, which largely determine the mechanical properties of the thread. Here, the structure-property relationships that govern thread mechanical performance are further probed. The molecular rearrangements that occur during yield and damage repair were investigated using time-resolved in situ wide-angle X-ray diffraction (WAXD) coupled with cyclic tensile loading of threads and through thermally enhanced damage-repair studies. Results indicate that the collagen domains in byssal preCols are mechanically protected by the unfolding of sacrificial non-collagenous domains that refold on a slower time-scale. Time-dependent healing is primarily attributed to stochastic recoupling of broken histidine-metal coordination complexes.

  11. On the role of baculovirus photolyases in DNA repair upon UV damage of occlusion bodies

    NARCIS (Netherlands)

    Biernat, M.A.; Caballero, P.; Vlak, J.M.; Oers, van M.M.

    2013-01-01

    The use of baculoviruses in insect biocontrol is hampered by their sensitivity to ultraviolet (UV) light. This irradiation induces cyclobutane pyrimidine dimers (CPDs) in DNA. CPD-photolyases repair CPDs using visible light. Plusiine baculoviruses encode photolyases, which could potentially repair

  12. A modelling study of drying shrinkage damage in concrete repair systems

    NARCIS (Netherlands)

    Lukovic, M.; Savija, B.; Schlangen, E.; Ye, G.; van Breugel, K.

    2014-01-01

    Differential shrinkage between repair material and concrete substrate is considered to be the main cause of premature failure of repair systems (Martinola, Sadouki et al. 2001, Beushausen and Alexander 2007). Magnitude of induced stresses depends on many factors, for example the amount of restraint,

  13. Type 3 innate lymphoid cells maintain intestinal epithelial stem cells after tissue damage.

    Science.gov (United States)

    Aparicio-Domingo, Patricia; Romera-Hernandez, Monica; Karrich, Julien J; Cornelissen, Ferry; Papazian, Natalie; Lindenbergh-Kortleve, Dicky J; Butler, James A; Boon, Louis; Coles, Mark C; Samsom, Janneke N; Cupedo, Tom

    2015-10-19

    Disruption of the intestinal epithelial barrier allows bacterial translocation and predisposes to destructive inflammation. To ensure proper barrier composition, crypt-residing stem cells continuously proliferate and replenish all intestinal epithelial cells within days. As a consequence of this high mitotic activity, mucosal surfaces are frequently targeted by anticancer therapies, leading to dose-limiting side effects. The cellular mechanisms that control tissue protection and mucosal healing in response to intestinal damage remain poorly understood. Type 3 innate lymphoid cells (ILC3s) are regulators of homeostasis and tissue responses to infection at mucosal surfaces. We now demonstrate that ILC3s are required for epithelial activation and proliferation in response to small intestinal tissue damage induced by the chemotherapeutic agent methotrexate. Multiple subsets of ILC3s are activated after intestinal tissue damage, and in the absence of ILC3s, epithelial activation is lost, correlating with increased pathology and severe damage to the intestinal crypts. Using ILC3-deficient Lgr5 reporter mice, we show that maintenance of intestinal stem cells after damage is severely impaired in the absence of ILC3s or the ILC3 signature cytokine IL-22. These data unveil a novel function of ILC3s in limiting tissue damage by preserving tissue-specific stem cells.

  14. Ebselen attenuates oxidative DNA damage and enhances its repair activity in the thalamus after focal cortical infarction in hypertensive rats.

    Science.gov (United States)

    He, Meixia; Xing, Shihui; Yang, Bo; Zhao, Liqun; Hua, Haiying; Liang, Zhijian; Zhou, Wenliang; Zeng, Jinsheng; Pei, Zhong

    2007-11-21

    Oxidative DNA damage has been proposed to be a major contributor to focal cerebral ischemic injury. However, little is known about the role of oxidative DNA damage in remote damage secondary to the primary infarction. In the present study, we investigated oxidative damage within the ventroposterior nucleus (VPN) after distal middle cerebral artery occlusion (MCAO) in hypertensive rats. We also examined the possible protective effect of ebselen, one glutathione peroxidase mimic, on delayed degeneration in the VPN after distal MCAO. Neuronal damage in the ipsilateral VPN was examined by Nissl staining. Oxidative DNA damage and base repair enzyme activity were assessed by analyzing immunoreactivity of 8-hydroxy-2'-deoxyguanosine (8-ohdG) and 8-oxoguanine DNA glycosylase (OGG1), respectively. The number of intact neurons in the ipsilateral VPN decreased by 52% compared to the contralateral side in ischemia group 2 weeks after distal cerebral cortical infarction. The immunoreactivity of 8-ohdG significantly increased while OGG1 immunoreactivity significantly decreased in the ipsilateral VPN 2 weeks after distal cortical infarction (all pVPN (all pVPN region following distal MCAO. Furthermore, ebselen protects against the delayed damage in the VPN when given at 24 h following distal MCAO.

  15. DNA damage and repair kinetics of the Alternaria mycotoxins alternariol, altertoxin II and stemphyltoxin III in cultured cells.

    Science.gov (United States)

    Fleck, Stefanie C; Sauter, Friederike; Pfeiffer, Erika; Metzler, Manfred; Hartwig, Andrea; Köberle, Beate

    2016-03-01

    The Alternaria mycotoxins alternariol (AOH) and altertoxin II (ATX II) have previously been shown to elicit mutagenic and genotoxic effects in bacterial and mammalian cells, although with vastly different activities. For example, ATX II was about 50 times more mutagenic than AOH. We now report that stemphyltoxin III (STTX III) is also highly mutagenic. The more pronounced effects of the perylene quinones ATX II and STTX III at lower concentrations compared to the dibenzo-α-pyrone AOH indicate a marked dependence of the genotoxic potential on the chemical structure and furthermore suggest that the underlying modes of action may be different. We have now further investigated the type of DNA damage induced by AOH, ATX II and STTX III, as well as the repair kinetics and their dependence on the status of nucleotide excision repair (NER). DNA double strand breaks induced by AOH due to poisoning of topoisomerase IIα were completely repaired in less than 2h. Under cell-free conditions, inhibition of topoisomerase IIα could also be measured for ATX II and STTX III at low concentrations, but the perylene quinones were catalytic inhibitors rather than topoisomerase poisons and did not induce DSBs. DNA strand breaks induced by ATX II and STTX III were more persistent and not completely repaired within 24h. A dependence of the repair rate on the NER status could only be demonstrated for STTX III, resulting in an accumulation of DNA damage in NER-deficient cells. Together with the finding that the DNA glycosylase formamidopyrimidine-DNA glycosylase (Fpg), but not T4 endonuclease V, is able to generate additional DNA strand breaks measurable by the alkaline unwinding assay, we conclude that the genotoxicity of the perylene quinones with an epoxide group is probably caused by the formation of DNA adducts which may be converted to Fpg sensitive sites.

  16. The UV-damaged DNA binding protein mediates efficient targeting of the nucleotide excision repair complex to UV-induced photo lesions

    NARCIS (Netherlands)

    Moser, J; Volker, M; Kool, H; Alekseev, S; Vrieling, H; Yasui, A; van Zeeland, AA; Mullenders, LHF

    2005-01-01

    Previous studies point to the XPC-hHR23B complex as the principal initiator of global genome nucleotide excision repair (NER) pathway, responsible for the repair of UV-induced cyclobutane pyrimidine dimers (CPD) and 6-4 photoproducts (6-4PP) in human cells. However, the UV-damaged DNA binding protei

  17. A tissue phantom for visualization and measurement of ultrasound-induced cavitation damage.

    Science.gov (United States)

    Maxwell, Adam D; Wang, Tzu-Yin; Yuan, Lingqian; Duryea, Alexander P; Xu, Zhen; Cain, Charles A

    2010-12-01

    Many ultrasound studies involve the use of tissue-mimicking materials to research phenomena in vitro and predict in vivo bioeffects. We have developed a tissue phantom to study cavitation-induced damage to tissue. The phantom consists of red blood cells suspended in an agarose hydrogel. The acoustic and mechanical properties of the gel phantom were found to be similar to soft tissue properties. The phantom's response to cavitation was evaluated using histotripsy. Histotripsy causes breakdown of tissue structures by the generation of controlled cavitation using short, focused, high-intensity ultrasound pulses. Histotripsy lesions were generated in the phantom and kidney tissue using a spherically focused 1-MHz transducer generating 15 cycle pulses, at a pulse repetition frequency of 100 Hz with a peak negative pressure of 14 MPa. Damage appeared clearly as increased optical transparency of the phantom due to rupture of individual red blood cells. The morphology of lesions generated in the phantom was very similar to that generated in kidney tissue at both macroscopic and cellular levels. Additionally, lesions in the phantom could be visualized as hypoechoic regions on a B-mode ultrasound image, similar to histotripsy lesions in tissue. High-speed imaging of the optically transparent phantom was used to show that damage coincides with the presence of cavitation. These results indicate that the phantom can accurately mimic the response of soft tissue to cavitation and provide a useful tool for studying damage induced by acoustic cavitation.

  18. Self repair of impacts, higher energy impacts, and earthquake damage in critical targets such as infrastructure components made of polymers and concrete

    Science.gov (United States)

    Dry, Carolyn

    2007-04-01

    The goal of our research has been to develop self-repairing matrices with unique toughness and strength for infrastructure and vehicles. Our revolutionary approach involves the autonomous release of repair chemicals from within the matrix itself. The repair agents are contained in hollow, structural fibers or beads that are embedded within the matrix. Under stress, the matrix senses external environmental factors and reacts by releasing the repair agents from within the hollow vessels. This autonomous response occurs wherever and whenever cracking, debonding or other matrix damage transpires. Superior performance over the life of the matrix is achieved through this self-repairing mechanism. The advantages are safely executed trips, fewer repairs and eventually lighter bridges and vehicles. Research to assess and clarify the impact of the various factors involved in self-repair of matrix materials has been the focus of our work for several years. Our research has addressed the issues by correlating the impact of the various factors, such as 1) delivery vessel, shape/size, coating, chemicals released, release trigger and efficacy and impact on matrix properties 2) influence of end use such as the importance of speed and force of release (airplane skin repair) 3) impact of processing methods that involve heat and pressure on the repair vessels. Our self repairing system can: be processed at temperatures of 350F, repairs in less than 30 seconds, and does not damage the matrix by repair fiber insertion. Unique toughness and strength is developed at damaged areas and material interfaces. Findings are based on testing in compression after impact, compression, fatigue, flexural toughness and flexure modes. The presentation will focus on highlighting the issues that were resolved in creating autonomous, self-repairing structures and vehicles.

  19. The recently identified P2Y-like receptor GPR17 is a sensor of brain damage and a new target for brain repair.

    Directory of Open Access Journals (Sweden)

    Davide Lecca

    Full Text Available Deciphering the mechanisms regulating the generation of new neurons and new oligodendrocytes, the myelinating cells of the central nervous system, is of paramount importance to address new strategies to replace endogenous damaged cells in the adult brain and foster repair in neurodegenerative diseases. Upon brain injury, the extracellular concentrations of nucleotides and cysteinyl-leukotrienes (cysLTs, two families of endogenous signaling molecules, are markedly increased at the site of damage, suggesting that they may act as "danger signals" to alert responses to tissue damage and start repair. Here we show that, in brain telencephalon, GPR17, a recently deorphanized receptor for both uracil nucleotides and cysLTs (e.g., UDP-glucose and LTD(4, is normally present on neurons and on a subset of parenchymal quiescent oligodendrocyte precursor cells. We also show that induction of brain injury using an established focal ischemia model in the rodent induces profound spatiotemporal-dependent changes of GPR17. In the lesioned area, we observed an early and transient up-regulation of GPR17 in neurons expressing the cellular stress marker heat shock protein 70. Magnetic Resonance Imaging in living mice showed that the in vivo pharmacological or biotechnological knock down of GPR17 markedly prevents brain infarct evolution, suggesting GPR17 as a mediator of neuronal death at this early ischemic stage. At later times after ischemia, GPR17 immuno-labeling appeared on microglia/macrophages infiltrating the lesioned area to indicate that GPR17 may also acts as a player in the remodeling of brain circuitries by microglia. At this later stage, parenchymal GPR17+ oligodendrocyte progenitors started proliferating in the peri-injured area, suggesting initiation of remyelination. To confirm a specific role for GPR17 in oligodendrocyte differentiation, the in vitro exposure of cortical pre-oligodendrocytes to the GPR17 endogenous ligands UDP-glucose and LTD(4

  20. An immunochemical approach to the study of DNA damage and repair. Technical progress report, May 1, 1989--April 30, 1992

    Energy Technology Data Exchange (ETDEWEB)

    Wallace, S.S. [Vermont Univ., Burlington, VT (United States). Dept. of Microbiology and Molecular Genetics; Erlanger, B.F. [Columbia Univ., New York, NY (United States). Dept. of Microbiology

    1992-05-01

    The overall objective of this project has been to develop immunochemical methods to quantitate unique DNA base damages in order to facilitate studies on radiation-induced damage production and repair. Specifically, we have been using antibodies raised to damaged bases to quantitate unique lesions in model systems in order to evaluate their potential biological consequences. Our approach has been to synthesize modified nucleotides or nucleosides, conjugate them to protein carriers, and use the conjugates as immunogens in rabbits or to prepare monoclonal antibodies. We have been studying damages that are stable radiolysis products found in X-irradiated DNA and thus of potential biological consequence. Our aim is to build an in vitro and in vivo data base on the interactions between model DNA lesions and such cellular enzymes as DNA polymerases and repair endonucleases. Initial studies have focused on pyrimidine ring saturation products (thymine glycol.and dihydrothymine), products resulting from ring fragmentation or base loss (urea, {Beta}-ureidoisobutyric acid, abasic sites), 7-hydro-8-oxopurines, and more recently, cytosine radiolysis products. These modified bases serve as useful models for examining the potential lethal and/or mutagenic (carcinogenic) effects of the products of DNA radiolysis.

  1. Modulation of DNA-induced damage and repair capacity in humans after dietary intervention with lutein-enriched fermented milk.

    Directory of Open Access Journals (Sweden)

    Carmen Herrero-Barbudo

    Full Text Available Dietary factors provide protection against several forms of DNA damage. Additionally, consumer demand for natural products favours the development of bioactive food ingredients with health benefits. Lutein is a promising biologically active component in the food industry. The EFSA Panel on Dietetic Products, Nutrition and Allergies considers that protection from oxidative damage may be a beneficial physiological effect but that a cause and effect relationship has not been established. Thus, our aim was to evaluate the safety and potential functional effect of a lutein-enriched milk product using the Comet Assay in order to analyze the baseline, the induced DNA-damage and the repair capacity in the lymphocytes of 10 healthy donors before and after the intake of the mentioned product. Our data suggest that the regular consumption of lutein-enriched fermented milk results in a significant increase in serum lutein levels and this change is associated with an improvement in the resistance of DNA to damage and the capacity of DNA repair in lymphocytes. Our results also support the lack of a genotoxic effect at the doses supplied as well as the absence of interactions and side effects on other nutritional and biochemicals markers.

  2. Repair of flexor tendon defects of rabbit with tissue engineering method

    Institute of Scientific and Technical Information of China (English)

    何清义; 李起鸿; 陈秉礼; 王智彪

    2002-01-01

    To repair rabbit tendon defects with tissue engineering method. Methods: The third passage of fetal skin fibroblast cells was labeled with 5-bromo-2' deoxyuridine (Brdu) and then seeded on human amnion extracellular matrix (HA-ECM). Using 1 cm-long-Achilles tendon .defects as repairing models in the experimental group, tendon defects were core bridged with polydioxanone (PDS) and then capsulated with the complex of fibroblasts-HA-ECM. In the control group I, defective tendons were sutured with PDS following the former procedure and capsulated with HA-ECM (without fibroblasts). In the control group Ⅱ,only PDS was applied to connect the defective tendons.Gross examination, light microscopy, scanning electronmicroscopy and biomechanical measurement of the repaired tendons were respectively performed at postoperative 1, 2, 3 month as well as immunohistochemical examination. Results: The optimal cell concentration for seeding fibroblasts was 3.5 × 106 cells/ml. Cells grew well and radiated or paralleled on HA-ECM. Immunohistochemistry showed that the labeled seed fibroblasts played an important role in tendonization. The results of light microscopy,electron microscopy, and biomechanical assessment suggested that the rate and quality of tendonization in the experimental group was superior to those of the control group Ⅰ and Ⅱ. The tensile strength in the experimental group was the greatest, the next was in the control group Ⅰ,and the worst in the control group Ⅱ ( P < 0.05). Conclusions: HA-ECM is the excellent carrier for fibroblasts. Fibroblasts-HA-ECM complex has the capability to repair tendon defect and to tendonize with rapid rate and good performance three months after operation. Its tensile strength is 81.8% of that of normal tendon.

  3. Repair of Minor Tissue Defect in Hand by Transfer of Free Tissue Flap from the Toe

    Directory of Open Access Journals (Sweden)

    Haitao Tan

    2014-03-01

    Full Text Available Background:   To introduce our experience of using the free neurovascular flap from great and second toe. Methods:   Thirteen patients (fifteen fingers sought surgical treatment for soft tissue defects of the hand at our medical institutin between March 2006 and September 2009. In two patients, fibular side skin-nail flaps of great toe were applied to cover the dorsal defect of distal thumb. In twelve, in the treatment of pulp defect of finger with fibular side flap of great toe or tibial side flap of second toe. In one, in the treatment of defect of distal middle with composite flap with distal digital bone of second toe. Results:   All flaps were survived. The average subjective satisfaction score was 8.08 (range 4-10. Nine patients (69% experienced cold intolerance, and 2 patients (15% dysesthesia. The Semmes-Weinstein sensitivity score was between 3.47and 4.72 on the flap, and 0-4.18 on the donor site. The mean two-point discrimination was 6.8 mm (range 4-12. Grip strength was 10% less than in the unaffected hand. The proximal interphalangeal mobility loss was less than 15 degrees. Conclusions:   Our results indicated that these free flaps from toe are useful for patients with a small soft-tissue defect in hand.

  4. ERCC2/XPD Lys751Gln alter DNA repair efficiency of platinum-induced DNA damage through P53 pathway.

    Science.gov (United States)

    Zhang, Guopei; Guan, Yangyang; Zhao, Yuejiao; van der Straaten, Tahar; Xiao, Sha; Xue, Ping; Zhu, Guolian; Liu, Qiufang; Cai, Yuan; Jin, Cuihong; Yang, Jinghua; Wu, Shengwen; Lu, Xiaobo

    2017-02-01

    Platinum-based treatment causes Pt-DNA adducts which lead to cell death. The platinum-induced DNA damage is recognized and repaired by the nucleotide excision repair (NER) system of which ERCC2/XPD is a critical enzyme. Single nucleotide polymorphisms in ERCC2/XPD have been found to be associated with platinum resistance. The aim of the present study was to investigate whether ERCC2/XPD Lys751Gln (rs13181) polymorphism is causally related to DNA repair capacity of platinum-induced DNA damage. First, cDNA clones expressing different genotypes of the polymorphism was transfected to an ERCC2/XPD defective CHO cell line (UV5). Second, all cells were treated with cisplatin. Cellular survival rate were investigated by MTT growth inhibition assay, DNA damage levels were investigated by comet assay and RAD51 staining. The distribution of cell cycle and the change of apoptosis rates were detected by a flow cytometric method (FCM). Finally, P53mRNA and phospho-P53 protein levels were further investigated in order to explore a possible explanation. As expected, there was a significantly increased in viability of UV5(ERCC2 (AA)) as compared to UV5(ERCC2 (CC)) after cisplatin treatment. The DNA damage level of UV5(ERCC2 (AA)) was significant decreased compared to UV5(ERCC2 (CC)) at 24 h of treatment. Mutation of ERCC2rs13181 AA to CC causes a prolonged S phase in cell cycle. UV5(ERCC2 (AA)) alleviated the apoptosis compared to UV5(ERCC2 (CC)), meanwhile P53mRNA levels in UV(ERCC2 (AA)) was also lower when compared UV5(ERCC2 (CC)). It co-incides with a prolonged high expression of phospho-P53, which is relevant for cell cycle regulation, apoptosis, and the DNA damage response (DDR). We concluded that ERCC2/XPD rs13181 polymorphism is possibly related to the DNA repair capacity of platinum-induced DNA damage. This functional study provides some clues to clarify the relationship between cisplatin resistance and ERCC2/XPDrs13181 polymorphism.

  5. Repair of acutely injured spinal cord through constructing tissue-engineered neural complex in adult rats

    Institute of Scientific and Technical Information of China (English)

    PU Yu; GUO Qing-shan; WANG Ai-min; WU Si-yu; XING Shu-xing; ZHANG Zhong-rong

    2007-01-01

    Objective: To construct tissue-engineered neural complex in vitro and study its effect in repairing acutely injured spinal cord in adult rats. Methods: Neural stem cells were harvested from the spinal cord of embryo rats and propagated in vitro. Then the neural stem cells were seeded into polyglycolic acid scaffolds and co-cultured with extract of embryonic spinal cord in vitro. Immunofluorescence histochemistry and scanning electron microscope were used to observe the microstructure of this complex. Animal model of spine semi-transection was made and tissue-engineered neural complex was implanted by surgical intervention. Six weeks after transplantation, functional evaluation and histochemistry were applied to evaluate the functional recovery and anatomic reconstruction. Results: The tissue-engineered neural complex had a distinct structure, which contained neonatal neurons, oligodendrocytes and astrocytes. After tissue-engineered neural complex was implanted into the injured spinal cord, the cell components such as neurons, astrocytes and oligodendrocytes, could survive and keep on developing. The adult rats suffering from spinal cord injury got an obvious neurological recovery in motor skills. Conclusions: The tissue-engineered neural complex appears to have therapeutic effects on the functional recovery and anatomic reconstruction of the adult rats with spinal cord injury.

  6. Direct Repair of Chronic Achilles Tendon Ruptures Using Scar Tissue Located Between the Tendon Stumps.

    Science.gov (United States)

    Yasuda, Toshito; Shima, Hiroaki; Mori, Katsunori; Kizawa, Momoko; Neo, Masashi

    2016-07-20

    Several surgical procedures for chronically ruptured Achilles tendons have been reported. Resection of the interposed scar tissue located between the tendon stumps and reconstruction using normal autologous tissue have been well described. We developed a direct repair procedure that uses scar tissue, which obviates the need to use normal autologous tissue. Thirty consecutive patients with Achilles tendon ruptures with a delay in diagnosis of >4 weeks underwent removal of a section of scar and healing tissue with direct primary suture of the ends of the tendon without the use of allograft or autograft. Patients were followed for a mean time of 33 months. Preoperative and postoperative clinical outcomes were measured with the Achilles Tendon Total Rupture Score (ATRS) and the American Orthopaedic Foot & Ankle Society (AOFAS) ankle-hindfoot score. In addition, the patients underwent preoperative and postoperative functional measurements and magnetic resonance imaging. Lastly, we evaluated the histology of the interposed healing tissue. The mean AOFAS scores were 82.8 points preoperatively and 98.1 points postoperatively. The mean postoperative ATRS was 92.0 points. At the time of the latest follow-up, none of the patients had experienced tendon reruptures or difficulties in walking or climbing stairs, and all except 2 patients could perform a single-limb heel rise. All athletes had returned to their pre-injury level of sports participation. Preoperative T2-weighted magnetic resonance imaging showed that 22 Achilles tendons were thickened with diffuse intratendinous high-signal alterations, and 8 Achilles tendons were thinned. Postoperative T2-weighted magnetic resonance imaging findings included fusiform-shaped tendon thickening and homogeneous low-signal alterations of the tendons in all patients. Histologically, the interposed scar tissue consisted of dense collagen fibers. Shortening of the tissue between the 2 tendon ends that included healing scar and direct

  7. A method to screen and evaluate tissue adhesives for joint repair applications

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    Dehne Tilo

    2012-09-01

    Full Text Available Abstract Background Tissue adhesives are useful means for various medical procedures. Since varying requirements cause that a single adhesive cannot meet all needs, bond strength testing remains one of the key applications used to screen for new products and study the influence of experimental variables. This study was conducted to develop an easy to use method to screen and evaluate tissue adhesives for tissue engineering applications. Method Tissue grips were designed to facilitate the reproducible production of substrate tissue and adhesive strength measurements in universal testing machines. Porcine femoral condyles were used to generate osteochondral test tissue cylinders (substrates of different shapes. Viability of substrates was tested using PI/FDA staining. Self-bonding properties were determined to examine reusability of substrates (n = 3. Serial measurements (n = 5 in different operation modes (OM were performed to analyze the bonding strength of tissue adhesives in bone (OM-1 and cartilage tissue either in isolation (OM-2 or under specific requirements in joint repair such as filling cartilage defects with clinical applied fibrin/PLGA-cell-transplants (OM-3 or tissues (OM-4. The efficiency of the method was determined on the basis of adhesive properties of fibrin glue for different assembly times (30 s, 60 s. Seven randomly generated collagen formulations were analyzed to examine the potential of method to identify new tissue adhesives. Results Viability analysis of test tissue cylinders revealed vital cells (>80% in cartilage components even 48 h post preparation. Reuse (n = 10 of test substrate did not significantly change adhesive characteristics. Adhesive strength of fibrin varied in different test settings (OM-1: 7.1 kPa, OM-2: 2.6 kPa, OM-3: 32.7 kPa, OM-4: 30.1 kPa and was increasing with assembly time on average (2.4-fold. The screening of the different collagen formulations revealed a substance with significant

  8. Cartilage Repair in the Inflamed Joint: Considerations for Biological Augmentation Toward Tissue Regeneration.

    Science.gov (United States)

    Scotti, Celeste; Gobbi, Alberto; Karnatzikos, Georgios; Martin, Ivan; Shimomura, Kazunori; Lane, John G; Peretti, Giuseppe Michele; Nakamura, Norimasa

    2016-04-01

    Cartilage repair/regeneration procedures (e.g., microfracture, autologous chondrocyte implantation [ACI]) typically result in a satisfactory outcome in selected patients. However, the vast majority of patients with chronic symptoms and, in general, a more diseased joint, do not benefit from these surgical techniques. The aims of this work were to (1) review factors negatively influencing the joint environment; (2) review current adjuvant therapies that can be used to improve results of cartilage repair/regeneration procedures in patients with more diseased joints, (3) outline future lines of research and promising experimental approaches. Chronicity of symptoms and advancing patient age appear to be the most relevant factors negatively affecting clinical outcome of cartilage repair/regeneration. Preliminary experience with hyaluronic acid, platelet-rich plasma, and mesenchymal stem cell has been positive but there is no strong evidence supporting the use of these products and this requires further assessment with high-quality, prospective clinical trials. The use of a Tissue Therapy strategy, based on more mature engineered tissues, holds promise to tackle limitations of standard ACI procedures. Current research has highlighted the need for more targeted therapies, and (1) induction of tolerance with granulocyte colony-stimulating factor (G-CSF) or by preventing IL-6 downregulation; (2) combined IL-4 and IL-10 local release; and (3) selective activation of the prostaglandin E2 (PGE2) signaling appear to be the most promising innovative strategies. For older patients and for those with chronic symptoms, adjuvant therapies are needed in combination with microfracture and ACI.

  9. A novel basalt fiber-reinforced polylactic acid composite for hard tissue repair.

    Science.gov (United States)

    Chen, Xi; Li, Yan; Gu, Ning

    2010-08-01

    A basalt fiber (BF) was, for the first time, introduced into a poly(l-lactic acid) (PLLA) matrix as innovative reinforcement to fabricate composite materials for hard tissue repair. Firstly, BF/PLLA composites and pure PLLA were produced by the methods of solution blending and freeze drying. The results showed that basalt fibers can be uniformly dispersed in the PLLA matrix and significantly improve the mechanical properties and hydrophilicity of the PLLA matrix. The presence of basalt fibers may retard the polymer degradation rate and neutralize the acid degradation from PLLA. Osteoblasts were cultured in vitro to evaluate the cytocompatibility of the composite. An MTT assay revealed that osteoblasts proliferated well for 7 days and there was little difference found in their viability on both PLLA and BF/PLLA films, which was consistent with the alkaline phosphatase (ALP) activity results. A fluorescent staining observation showed that osteoblasts grew well on the composites. SEM images displayed that osteoblasts tended to grow along the fiber axis. The formation of mineralized nodules was observed on the films by Alizarin red S staining. These results suggest that the presence of basalt fibers does not noticeably affect osteoblastic behavior and the designed composites are osteoblast compatible. It is concluded that basalt fibers, as reinforcing fibers, may have promising applications in hard tissue repair.

  10. Polymorphisms in genes controlling inflammation and tissue repair in rheumatoid arthritis: a case control study

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    de Vogel Lisette

    2011-03-01

    Full Text Available Abstract Background Various cytokines and inflammatory mediators are known to be involved in the pathogenesis of rheumatoid arthritis (RA. We hypothesized that polymorphisms in selected inflammatory response and tissue repair genes contribute to the susceptibility to and severity of RA. Methods Polymorphisms in TNFA, IL1B, IL4, IL6, IL8, IL10, PAI1, NOS2a, C1INH, PARP, TLR2 and TLR4 were genotyped in 376 Caucasian RA patients and 463 healthy Caucasian controls using single base extension. Genotype distributions in patients were compared with those in controls. In addition, the association of polymorphisms with the need for anti-TNF-α treatment as a marker of RA severity was assessed. Results The IL8 781 CC genotype was associated with early onset of disease. The TNFA -238 G/A polymorphism was differentially distributed between RA patients and controls, but only when not corrected for age and gender. None of the polymorphisms was associated with disease severity. Conclusions We here report an association between IL8 781 C/T polymorphism and age of onset of RA. Our findings indicate that there might be a role for variations in genes involved in the immune response and in tissue repair in RA pathogenesis. Nevertheless, additional larger genomic and functional studies are required to further define their role in RA.

  11. Tissue repair genes: the TiRe database and its implication for skin wound healing.

    Science.gov (United States)

    Yanai, Hagai; Budovsky, Arie; Tacutu, Robi; Barzilay, Thomer; Abramovich, Amir; Ziesche, Rolf; Fraifeld, Vadim E

    2016-04-19

    Wound healing is an inherent feature of any multicellular organism and recent years have brought about a huge amount of data regarding regular and abnormal tissue repair. Despite the accumulated knowledge, modulation of wound healing is still a major biomedical challenge, especially in advanced ages. In order to collect and systematically organize what we know about the key players in wound healing, we created the TiRe (Tissue Repair) database, an online collection of genes and proteins that were shown to directly affect skin wound healing. To date, TiRe contains 397 entries for four organisms: Mus musculus, Rattus norvegicus, Sus domesticus, and Homo sapiens. Analysis of the TiRe dataset of skin wound healing-associated genes showed that skin wound healing genes are (i) over-conserved among vertebrates, but are under-conserved in invertebrates; (ii) enriched in extracellular and immuno-inflammatory genes; and display (iii) high interconnectivity and connectivity to other proteins. The latter may provide potential therapeutic targets. In addition, a slower or faster skin wound healing is indicative of an aging or longevity phenotype only when assessed in advanced ages, but not in the young. In the long run, we aim for TiRe to be a one-station resource that provides researchers and clinicians with the essential data needed for a better understanding of the mechanisms of wound healing, designing new experiments, and the development of new therapeutic strategies. TiRe is freely available online at http://www.tiredb.org.

  12. The influence of platelet- derived products on angiogenesis and tissue repair: a concise update

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    Constanza E Martínez

    2015-10-01

    Full Text Available Platelet degranulation allows the release of a large amount of soluble mediators, is an essential step for wound healing initiation, and stimulates clotting and angiogenesis. The latter process is one of the most critical biological events observed during tissue repair,increasing the growth of blood vessels in the maturing wound. Angiogenesis requires the action of a variety of growth factors that act in an appropriate physiological ratio to assure functional blood vessel restoration. Platelets release main regulators of angiogenesis: Vascular Endothelial Growth Factors (VEGFs, basic fibroblast growth factor (FGF-2, and Platelet derived growth factors (PDGFs, among others. In order to stimulate tissue repair, platelet derived fractions have been used as an autologous source of growth factors and biomolecules, namely Platelet Rich Plasma (PRP, Platelet Poor Plasma (PPP and Platelet Rich Fibrin(PRF. The continuous release of these growth factors has been proposed to promote angiogenesis both in vitro and in vivo. Considering the existence of clinical trials currently evaluating the efficacy of autologous PRP, the present review analyses fundamental questions regarding the putative role of platelet derived fractions as regulators of angiogenesis and evaluates the possible clinical implications of these formulations.

  13. The influence of platelet-derived products on angiogenesis and tissue repair: a concise update

    Science.gov (United States)

    Martínez, Constanza E.; Smith, Patricio C.; Palma Alvarado, Verónica A.

    2015-01-01

    Platelet degranulation allows the release of a large amount of soluble mediators, is an essential step for wound healing initiation, and stimulates clotting, and angiogenesis. The latter process is one of the most critical biological events observed during tissue repair, increasing the growth of blood vessels in the maturing wound. Angiogenesis requires the action of a variety of growth factors that act in an appropriate physiological ratio to assure functional blood vessel restoration. Platelets release main regulators of angiogenesis: Vascular Endothelial Growth Factors (VEGFs), basic fibroblast growth factor (FGF-2), and Platelet derived growth factors (PDGFs), among others. In order to stimulate tissue repair, platelet derived fractions have been used as an autologous source of growth factors and biomolecules, namely Platelet Rich Plasma (PRP), Platelet Poor Plasma (PPP), and Platelet Rich Fibrin (PRF). The continuous release of these growth factors has been proposed to promote angiogenesis both in vitro and in vivo. Considering the existence of clinical trials currently evaluating the efficacy of autologous PRP, the present review analyses fundamental questions regarding the putative role of platelet derived fractions as regulators of angiogenesis and evaluates the possible clinical implications of these formulations. PMID:26539125

  14. Hiatal Hernia Repair with Gore Bio-A Tissue Reinforcement: Our Experience

    Directory of Open Access Journals (Sweden)

    Agrusa Antonino

    2014-01-01

    Full Text Available Type I hiatal hernia is associated with gastroesophageal reflux disease (GERD in 50–90% of cases. Several trials strongly support surgery as an effective alternative to medical therapy. Today, laparoscopic fundoplication is considered as the procedure of choice. However, primary laparoscopic hiatal hernia repair is associated with upto 42% recurrence rate. Mesh reinforcement of the crural closure decreases the recurrence but can lead to complications, above all nonabsorbable ones. We experiment a new totally absorbable mesh by Gore. Case. We present a case of a 65-year-old female patient with a 6-year classic history of GERD. Endoscopy revealed a large hiatal hernia and esophagitis. pH study was positive for acid reflux; esophageal manometry revealed LES intrathoracic dislocation. With laparoscopic approach, the hiatal hernia defect was identified and primarily repaired, by crural closure. Gore Bio-A Tissue Reinforcement was trimmed to fit the defect accommodating the esophagus. Nissen fundoplication was performed. Result. Bio-A mesh was easily placed laparoscopically. It has good handling and could be cut and tailored intraoperatively for optimal adaptation. There were no short-term complications. Conclusion. Crural closure reinforcement can be done readily with this new totally absorbable mesh replaced by soft tissue over six months. However, further data and studies are needed to evaluate long-term outcomes.

  15. Analysis of photobiomodulation associated or not with platelet-rich plasma on repair of muscle tissue by Raman spectroscopy.

    Science.gov (United States)

    Ozaki, Guilherme Akio Tamura; Camargo, Regina Celi Trindade; Koike, Tatiana Emy; Garcia, Thiago Alves; Castoldi, Robson Chacon; Pereira, João Domingos Augusto Dos Santos; Constantino, Carlos José Leopoldo; Camargo Filho, José Carlos Silva

    2016-12-01

    Treatment of muscle injuries usually results in the interruption of sports practice; thus, studies aimed at accelerating the return to activity, with proper tissue repair, are important. Therefore, this study aimed to evaluate the effects of photobiomodulation (PBM), associated or not with platelet-rich plasma (PRP), on the treatment of muscle injury. Thirty-five animals were used and divided into five groups (n = 7): control (C), control lesion (CL), lesion treated with low-level laser therapy (LLLT) (LLt), lesion treated with PRP (LP), and lesion treated with both techniques, LLLT and PRP (LLtP). Muscle injury was induced by stretching the gastrocnemius muscle, and the animals in the LLtP and LP groups received the application of PRP immediately following the injury. The LLLT was applied daily for 7 days. The animals were euthanized 7 days after the injury. Analysis of the NADH/NAD ratio and collagen was performed by Raman spectroscopy; in addition to which, histological analysis of the gastrocnemius muscle was performed. The LLtP group demonstrated a reduction in the area of injury, regenerating cells and a healthy appearance of muscle fibers. The Raman analyses showed a reduction in the NADH/NAD ratio in the CL group, demonstrating oxidative stress, and the collagen presented a reduction in the CL and LLt groups, when compared with the C group. It is concluded that either PBM or PRP, and the association of both, was able to reduce the oxidative stress promoted by injury and modulate collagen production at the site of the injury. Furthermore, although both treatments individually were effective for repairing the damage caused by muscle injury, the association of both demonstrated a better histological aspect.

  16. HGF-transgenic MSCs can improve the effects of tissue self-repair in a rabbit model of traumatic osteonecrosis of the femoral head.

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    Qian Wen

    Full Text Available BACKGROUND: Osteonecrosis of the femoral head (ONFH is generally characterized as an irreversible disease and tends to cause permanent disability. Therefore, understanding the pathogenesis and molecular mechanisms of ONFH and developing effective therapeutic methods is critical for slowing the progress of the disease. METHODOLOGY/PRINCIPAL FINDINGS: In this study, an experimental rabbit model of early stage traumatic ONFH was established, validated, and used for an evaluation of therapy. Computed tomography (CT and magnetic resonance (MR imaging confirmed that this model represents clinical Association Research Circulation Osseous (ARCO phase I or II ONFH, which was also confirmed by the presence of significant tissue damage in osseous tissue and vasculature. Pathological examination detected obvious self-repair of bone tissue up to 2 weeks after trauma, as indicated by revascularization (marked by CD105 and expression of collagen type I (Col I, osteocalcin, and proliferating cell nuclear antigen. Transplantation of hepatocyte growth factor (HGF-transgenic mesenchymal stem cells (MSCs 1 week after trauma promoted recovery from ONFH, as evidenced by a reversed pattern of Col I expression compared with animals receiving no therapeutic treatment, as well as increased expression of vascular endothelial growth factor. CONCLUSIONS/SIGNIFICANCE: These results indicate that the transplantation of HGF-transgenic MSCs is a promising method for the treatment for ONFH and suggest that appropriate interference therapy during the tissue self-repair stage contributes to the positive outcomes. This study also provides a model for the further study of the ONFH etiology and therapeutic interventions.

  17. Expression of MLL-AF4 or AF4-MLL fusions does not impact the efficiency of DNA damage repair.

    Science.gov (United States)

    Castaño, Julio; Herrero, Ana B; Bursen, Aldeheid; González, Federico; Marschalek, Rolf; Gutiérrez, Norma C; Menendez, Pablo

    2016-05-24

    The most frequent rearrangement of the human MLL gene fuses MLL to AF4 resulting in high-risk infant B-cell acute lymphoblastic leukemia (B-ALL). MLL fusions are also hallmark oncogenic events in secondary acute myeloid leukemia. They are a direct consequence of mis-repaired DNA double strand breaks (DNA-DSBs) due to defects in the DNA damage response associated with exposure to topoisomerase-II poisons such as etoposide. It has been suggested that MLL fusions render cells susceptible to additional chromosomal damage upon exposure to etoposide. Conversely, the genome-wide mutational landscape in MLL-rearranged infant B-ALL has been reported silent. Thus, whether MLL fusions compromise the recognition and/or repair of DNA damage remains unanswered. Here, the fusion proteins MLL-AF4 (MA4) and AF4-MLL (A4M) were CRISPR/Cas9-genome edited in the AAVS1 locus of HEK293 cells as a model to study MLL fusion-mediated DNA-DSB formation/repair. Repair kinetics of etoposide- and ionizing radiation-induced DSBs was identical in WT, MA4- and A4M-expressing cells, as revealed by flow cytometry, by immunoblot for γH2AX and by comet assay. Accordingly, no differences were observed between WT, MA4- and A4M-expressing cells in the presence of master proteins involved in non-homologous end-joining (NHEJ; i.e.KU86, KU70), alternative-NHEJ (Alt-NHEJ; i.e.LigIIIa, WRN and PARP1), and homologous recombination (HR, i.e.RAD51). Moreover, functional assays revealed identical NHEJ and HR efficiency irrespective of the genotype. Treatment with etoposide consistently induced cell cycle arrest in S/G2/M independent of MA4/A4M expression, revealing a proper activation of the DNA damage checkpoints. Collectively, expression of MA4 or A4M does neither influence DNA signaling nor DNA-DSB repair.

  18. Changes of color coordinates of biological tissue with superficial skin damage due to mechanical trauma

    Science.gov (United States)

    Pteruk, Vail; Mokanyuk, Olexander; Kvaternuk, Olena; Yakenina, Lesya; Kotyra, Andrzej; Romaniuk, Ryszard S.; Dussembayeva, Shynar

    2015-12-01

    Change of color coordinates of normal and pathological biological tissues is based on calculated spectral diffuse reflection. The proposed color coordinates of normal and pathological biological tissues of skin provided using standard light sources, allowing accurately diagnose skin damage due to mechanical trauma with a blunt object for forensic problems.

  19. Role of mucus in the repair of gastric epithelial damage in the rat. Inhibition of epithelial recovery by mucolytic agents.

    Science.gov (United States)

    Wallace, J L; Whittle, B J

    1986-09-01

    A role for mucus in providing a microenvironment over sites of gastric damage, which is conducive to reepithelialization, has been proposed. We tested this hypothesis by examining the effects of disruption of such mucus on the recovery of epithelial integrity after damage induced by 50% ethanol. Exposure of an ex vivo chambered gastric mucosa to topically applied 50% ethanol resulted in copious release of mucus, cellular debris, and plasma, which formed a continuous cap over the mucosal surface. Ethanol-induced gastric damage was accompanied by extensive surface epithelial cell damage and a marked decrease in transmucosal potential difference. During the 30 min after ethanol was removed from the chamber, the epithelium became reestablished and the potential difference gradually recovered to 94% of the level before ethanol treatment. However, if the mucolytic agents N-acetylcysteine (5%) or pepsin (0.5%) were added to the bathing solutions, the "mucoid cap" disintegrated and the recovery of potential difference was significantly retarded (recovering to only 51% and 52% of levels before ethanol treatment). Histologic evaluation confirmed that mucosae treated with either agent had significantly less (p less than 0.005) intact epithelium at the end of the experiment. Removal of the mucoid cap with forceps caused a similar inhibition of the repair of the epithelium and the recovery of potential difference. Both mechanical and chemical (N-acetylcysteine) disruption of the mucoid cap resulted in a significant increase in the mucosal leakage of albumin and hemoglobin, supporting previous histologic evidence that the mucoid cap traps blood components over the damaged mucosa. These studies support the hypothesis that mucus released in response to topical application of an irritant plays an important role in the repair of epithelial damage through the process of restitution.

  20. Anatomical basis of neuropathies and damage to the ilioinguinal nerve during repairs of groin hernias. (about 100 dissections).

    Science.gov (United States)

    Ndiaye, A; Diop, M; Ndoye, J M; Konaté, I; Ndiaye, A I; Mané, L; Nazarian, S; Dia, A

    2007-12-01

    Surgical access to the inguinal region, notably during hernia repairs, exposes the ilioinguinal nerve to the risk of damage at the origin of the neuralgia. The incidence of these post-operative neuropathies and their medicolegal consequences justify this study about the anatomical variations of the ilioinguinal nerve. With the aim of preventing its damage during repairs of groin hernias and identifying the factors of onset of chronic spontaneous neuropathy of the ilioinguinal nerve, we dissected 100 inguinal regions of 51 fresh adult corpses. The nerve was absent in seven cases and double in one case. Out of the 94 ilioinguinal nerves observed, we analyzed the path in relation to the inguinal ligament and the connections with the walls of the inguinal canal and its content. The ilioinguinal nerve travels along the superficial surface of the internal oblique muscle, passing on average 1.015 cm from the inguinal ligament. In one case, the fibers of the internal oblique muscle spanned it in several places. The nerve was antero-funicular in 78.72% of cases and perforated the fascia of the external oblique in 28.72% of cases. The terminal division took place in the inguinal canal in 86% of cases, with terminal branches that sometimes perforated the fascia of the external oblique. These results enabled us to better understand the etiopathogenic aspects of certain neuropathies of the groin and to propose techniques useful for the protection of the nerve during repairs of groin hernias.

  1. Application of immunohistochemical staining to detect antigen destruction as a measure of tissue damage.

    Science.gov (United States)

    Onul, Abdullah; Colvard, Michael D; Paradise, William A; Elseth, Kim M; Vesper, Benjamin J; Gouvas, Eftychia; Deliu, Zane; Garcia, Kelly D; Pestle, William J; Radosevich, James A

    2012-09-01

    Electrocautery and directed energy devices (DEDs) such as lasers, which are used in surgery, result in tissue damage that cannot be readily detected by traditional histological methods, such as hematoxylin and eosin staining. Alternative staining methods, including 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) to stain live tissue, have been reported. Despite providing superior detection of damaged tissue relative to the hematoxylin and eosin (H&E) method, the MTT method possesses a number of drawbacks, most notably that it must be carried out on live tissue samples. Herein, we report the development of a novel staining method, "antigen destruction immunohistochemistry" (ADI), which can be carried out on paraffin-embedded tissue. The ADI method takes advantage of epitope loss to define the area of tissue damage and provides many of the benefits of live tissue MTT staining without the drawbacks inherent to that method. In addition, the authors provide data to support the use of antibodies directed at a number of gene products for use in animal tissue for which there are no species-specific antibodies commercially available, as well as an example of a species-specific direct antibody. Data are provided that support the use of this method in many tissue models, as well as evidence that ADI is comparable to the live tissue MTT method.

  2. Effect of mechanical tissue properties on thermal damage in skin after IR-laser ablation

    Science.gov (United States)

    Frenz, M.; Mischler, Ch.; Romano, V.; Forrer, M.; Müller, O. M.; Weber, H. P.

    1991-04-01

    The damage created instantaneously in dorsal skin and in the subjacent skeletal muscle layer after CO2 and Er3+ laser incisions is histologically and ultrastructurally investigated. Light microscopical examinations show an up to three times larger damage zone in the subcutaneous layer of skeletal muscle than in the connective tissue above. The extent of thermally altered muscle tissue is classified by different zones and characterized by comparison to long time heating injuries. The unexpectedly large damage is a result of the change of elastic properties occurring abruptly at the transition between different materials. This leads to a discontinuity of the cutting dynamics that reduces the ejection of tissue material. We show that the degree of thermal damage originates from the amount of hot material that is not ejected out of the crater acting as a secondary heat source.

  3. Application of a molecular biology concept for the detection of DNA damage and repair during UV disinfection.

    Science.gov (United States)

    Süss, Jacqueline; Volz, Sabrina; Obst, Ursula; Schwartz, Thomas

    2009-08-01

    As nucleic acids are major targets in bacteria during standardised UV disinfection (254 nm), inactivation rates also depend on bacterial DNA repair. Due to UV-related DNA modifications, PCR-based approaches allow for a direct detection of DNA damage and repair during UV disinfection. By applying different primer sets, the correlation between amplicon length and PCR amplification became obvious. The longer the targeted DNA fragment was, the more UV-induced DNA lesions inhibited the PCR. Regeneration of Pseudomonas aeruginosa, Enterococcus faecium, and complex wastewater communities was recorded over a time period of 66 h. While phases of intensive repair and proliferation were found for P. aeruginosa, no DNA repair was detected by qPCR in E. faecium. Cultivation experiments verified these results. Despite high UV mediated inactivation rates original wastewater bacteria seem to express an enhanced robustness against irradiation. Regeneration of dominant and proliferation of low-abundant, probably UV-resistant species contributed to a strong post-irradiation recovery accompanied by a selection for beta-Proteobacteria.

  4. The application of lesion sterilization and tissue repair 3Mix-MP for treating rat's dental pulp tissue

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    Raditya Nugroho

    2015-03-01

    Full Text Available Background: Lesion sterilization and tissue repair (LSTR 3Mix-MP are three broad-spectrum antibiotics, including metronidazole, ciprofloxacin and minocycline are mixed with propylene glycol or macrogol. There is the possibility ofthe healing process that marked proliferation ofnew blood vessels and proliferation offibroblasts in the treatment ofirreversible pulpitis by pulp capping LSTR 3MixMP because of  the principle of the method LSTR 3Mix-MP is to kill bacteria. Purpose: The purpose of this study to prove the effect of LSTR 3Mix-MP on chronic inflammation and the healing process in rat dental pulp tissue in vivo. Methods: Rattus norvegicus anaesthetized by using ketamine and xylazine dissolved in sterile isotonic saline solution (0.2 ml/50gr mm on the upper right thigh. Cavity preparation class I to perforation by using a low speed tapered diamond round bur. In the treatment group, rats were treated 3Mix-MP at a dose of10 mg and then covered with glass ionomer cement for 7 days on the pulp that has been opened for 3 days. The control group treated with saline irrigation on the pulp that has been opened for 3 days. Rats were killed after seven days, and then made preparations pulp tissue to count the number oflymphocytes, macrophages, plasma cells, blood vessels, and fibroblasts Results: There is an increase in the average number ofmacrophage cells, plasma, and fibroblasts; and decreased lymphocytes and blood vessels in the treated group exposure LSTR 3Mix-MP. Conclusion:LSTR 3Mix-MP can reduce chronic inflammation process and enhance the healing process in rat dental pulp tissue.

  5. Alkylation damage in DNA and RNA--repair mechanisms and medical significance

    DEFF Research Database (Denmark)

    Drabløs, Finn; Feyzi, Emadoldin; Aas, Per Arne

    2004-01-01

    Alkylation lesions in DNA and RNA result from endogenous compounds, environmental agents and alkylating drugs. Simple methylating agents, e.g. methylnitrosourea, tobacco-specific nitrosamines and drugs like temozolomide or streptozotocin, form adducts at N- and O-atoms in DNA bases. These lesions...... are mainly repaired by direct base repair, base excision repair, and to some extent by nucleotide excision repair (NER). The identified carcinogenicity of O(6)-methylguanine (O(6)-meG) is largely caused by its miscoding properties. Mutations from this lesion are prevented by O(6)-alkylG-DNA alkyltransferase......, inactivation of the MMR system in an AGT-defective background causes resistance to the killing effects of O(6)-alkylating agents, but not to the mutagenic effect. Bifunctional alkylating agents, such as chlorambucil or carmustine (BCNU), are commonly used anti-cancer drugs. DNA lesions caused by these agents...

  6. RESTORING A DAMAGED 16-YEAR -OLD INSULATING POLYMER CONCRETE DIKE OVERLAY: REPAIR MATERIALS AND TECHNOLOGIES.

    Energy Technology Data Exchange (ETDEWEB)

    SUGAMA,T.

    2007-01-01

    The objective of this program was to design and formulate organic polymer-based material systems suitable for repairing and restoring the overlay panels of insulating lightweight polymer concrete (ILPC) from the concrete floor and slope wall of a dike at KeySpan liquefied natural gas (LNG) facility in Greenpoint, Brooklyn, NY, just over sixteen years ago. It also included undertaking a small-scale field demonstration to ensure that the commercial repairing technologies were applicable to the designed and formulated materials.

  7. Molecular Mechanisms of Ultraviolet Radiation-Induced DNA Damage and Repair

    Directory of Open Access Journals (Sweden)

    Rajesh P. Rastogi

    2010-01-01

    Full Text Available DNA is one of the prime molecules, and its stability is of utmost importance for proper functioning and existence of all living systems. Genotoxic chemicals and radiations exert adverse effects on genome stability. Ultraviolet radiation (UVR (mainly UV-B: 280–315 nm is one of the powerful agents that can alter the normal state of life by inducing a variety of mutagenic and cytotoxic DNA lesions such as cyclobutane-pyrimidine dimers (CPDs, 6-4 photoproducts (6-4PPs, and their Dewar valence isomers as well as DNA strand breaks by interfering the genome integrity. To counteract these lesions, organisms have developed a number of highly conserved repair mechanisms such as photoreactivation, base excision repair (BER, nucleotide excision repair (NER, and mismatch repair (MMR. Additionally, double-strand break repair (by homologous recombination and nonhomologous end joining, SOS response, cell-cycle checkpoints, and programmed cell death (apoptosis are also operative in various organisms with the expense of specific gene products. This review deals with UV-induced alterations in DNA and its maintenance by various repair mechanisms.

  8. DSB repair model for mammalian cells in early S and G1 phases of the cell cycle: application to damage induced by ionizing radiation of different quality.

    Science.gov (United States)

    Taleei, Reza; Girard, Peter M; Nikjoo, Hooshang

    2015-02-01

    The purpose of this work is to test the hypothesis that kinetics of double strand breaks (DSB) repair is governed by complexity of DSB. To test the hypothesis we used our recent published mechanistic mathematical model of DSB repair for DSB induced by selected protons, deuterons, and helium ions of different energies representing radiations of different qualities. In light of recent advances in experimental and computational techniques, the most appropriate method to study cellular responses in radiation therapy, and exposures to low doses of ionizing radiations is using mechanistic approaches. To this end, we proposed a 'bottom-up' approach to study cellular response that starts with the DNA damage. Monte Carlo track structure method was employed to simulate initial damage induced in the genomic DNA by direct and indirect effects. Among the different types of DNA damage, DSB are known to be induced in simple and complex forms. The DSB repair model in G1 and early S phases of the cell cycle was employed to calculate the repair kinetics. The model considers the repair of simple and complex DSB, and the DSB produced in the heterochromatin. The inverse sampling method was used to calculate the repair kinetics for each individual DSB. The overall repair kinetics for 500 DSB induced by single tracks of the radiation under test were compared with experimental results. The results show that the model is capable of predicting the repair kinetics for the DSB induced by radiations of different qualities within an accepted range of uncertainty.

  9. The Base Excision Repair system of Salmonella enterica serovar typhimurium counteracts DNA damage by host nitric oxide.

    Directory of Open Access Journals (Sweden)

    Anthony R Richardson

    2009-05-01

    Full Text Available Intracellular pathogens must withstand nitric oxide (NO. generated by host phagocytes. Salmonella enterica serovar Typhimurium interferes with intracellular trafficking of inducible nitric oxide synthase (iNOS and possesses multiple systems to detoxify NO.. Consequently, the level of NO. stress encountered by S. Typhimurium during infection in vivo has been unknown. The Base Excision Repair (BER system recognizes and repairs damaged DNA bases including cytosine and guanine residues modified by reactive nitrogen species. Apurinic/apyrimidinic (AP sites generated by BER glycosylases require subsequent processing by AP endonucleases. S. Typhimurium xth nfo mutants lacking AP endonuclease activity exhibit increased NO. sensitivity resulting from chromosomal fragmentation at unprocessed AP sites. BER mutant strains were thus used to probe the nature and extent of nitrosative damage sustained by intracellular bacteria during infection. Here we show that an xth nfo S. Typhimurium mutant is attenuated for virulence in C3H/HeN mice, and virulence can be completely restored by the iNOS inhibitor L-NIL. Inactivation of the ung or fpg glycosylase genes partially restores virulence to xth nfo mutant S. Typhimurium, demonstrating that NO. fluxes in vivo are sufficient to modify cytosine and guanine bases, respectively. Mutants lacking ung or fpg exhibit NO.-dependent hypermutability during infection, underscoring the importance of BER in protecting Salmonella from the genotoxic effects of host NO.. These observations demonstrate that host-derived NO. damages Salmonella DNA in vivo, and the BER system is required to maintain bacterial genomic integrity.

  10. Damage escape and repair in dried Chroococcidiopsis spp. from hot and cold deserts exposed to simulated space and martian conditions.

    Science.gov (United States)

    Billi, Daniela; Viaggiu, Emanuela; Cockell, Charles S; Rabbow, Elke; Horneck, Gerda; Onofri, Silvano

    2011-01-01

    The cyanobacterium Chroococcidiopsis, overlain by 3 mm of Antarctic sandstone, was exposed as dried multilayers to simulated space and martian conditions. Ground-based experiments were conducted in the context of Lichens and Fungi Experiments (EXPOSE-E mission, European Space Agency), which were performed to evaluate, after 1.5 years on the International Space Station, the survival of cyanobacteria (Chroococcidiopsis), lichens, and fungi colonized on Antarctic rock. The survival potential and the role played by protection and repair mechanisms in the response of dried Chroococcidiopsis cells to ground-based experiments were both investigated. Different methods were employed, including evaluation of the colony-forming ability, single-cell analysis of subcellular integrities based on membrane integrity molecular and redox probes, evaluation of the photosynthetic pigment autofluorescence, and assessment of the genomic DNA integrity with a PCR-based assay. Desiccation survivors of strain CCMEE 123 (coastal desert, Chile) were better suited than CCMEE 134 (Beacon Valley, Antarctica) to withstand cellular damage imposed by simulated space and martian conditions. Exposed dried cells of strain CCMEE 123 formed colonies, maintained subcellular integrities, and, depending on the exposure conditions, also escaped DNA damage or repaired the induced damage upon rewetting.

  11. Potential Role of Dentin Sialoprotein by Inducing Dental Pulp Mesenchymal Stem Cell Differentiation and Mineralization for Dental Tissue Repair

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    Zhi Chen

    2010-09-01

    Full Text Available Introduction: Dentin sialoprotein (DSP is a dentin extracellular matrix protein, a unique marker of dentinogenesis and plays a vital role in odontoblast differentiation and dentin mineralization. Recently, studies have shown that DSP induces differentiation and mineralization of periodontal ligament stem cells and dental papilla mesenchymal cells in vitro and rescues dentin deficiency and increases enamel mineralization in animal models.The hypothesis: DSP as a nature therapeutic agent stimulates dental tissue repair by inducing endogenous dental pulp mesenchymal stem/progenitor cells into odontoblast-like cells to synthesize and to secrete dentin extracellular matrix forming new tertiary dentin as well as to regenerate a functional dentin-pulp complex. As DSP is a nature protein, and clinical procedure for DSP therapy is easy and simple, application of DSP may provide a new avenue for dentists with additional option for the treatment of substantially damaged vital teeth.Evaluation of the hypothesis: Dental caries is the most common dental disease. Deep caries and pulp exposure have been treated by various restorative materials with limited success. One promising approach is dental pulp stem/progenitor-based therapies to regenerate dentin-pulp complex and restore its functions by DSP induction in vivo.

  12. Damaged beyond repair? Characterising the damage zone of a fault late in its interseismic cycle, the Alpine Fault, New Zealand

    Science.gov (United States)

    Williams, Jack N.; Toy, Virginia G.; Massiot, Cécile; McNamara, David D.; Wang, Ting

    2016-09-01

    X-ray computed tomography (CT) scans of drill-core, recovered from the first phase of the Deep Fault Drilling Project (DFDP-1) through New Zealand's Alpine Fault, provide an excellent opportunity to study the damage zone of a plate-bounding continental scale fault, late in its interseismic cycle. Documentation of the intermediate-macro scale damage zone structures observed in the CT images show that there is no increase in the density of these structures towards the fault's principal slip zones (PSZs), at least within the interval sampled, which is 30 m above and below the PSZs. This is in agreement with independent analysis using borehole televiewer data. Instead, we conclude the density of damage zone structures to correspond to lithology. We find that 72% of fractures are fully healed, by a combination of clays, calcite and quartz, with an additional 24% partially healed. This fracture healing is consistent with the Alpine Fault's late interseismic state, and the fact that the interval of damage zone sampled coincides with an alteration zone, an interval of extensive fluid-rock interaction. These fractures do not impose a reduction of P-wave velocity, as measured by wireline methods. Outside the alteration zone there is indirect evidence of less extensive fracture healing.

  13. Urban seismic risk assessment: statistical repair cost data and probable structural losses based on damage scenario—correlation analysis

    Science.gov (United States)

    Eleftheriadou, Anastasia K.; Baltzopoulou, Aikaterini D.; Karabinis, Athanasios I.

    2016-06-01

    The current seismic risk assessment is based on two discrete approaches, actual and probable, validating afterwards the produced results. In the first part of this research, the seismic risk is evaluated from the available data regarding the mean statistical repair/strengthening or replacement cost for the total number of damaged structures (180,427 buildings) after the 7/9/1999 Parnitha (Athens) earthquake. The actual evaluated seismic risk is afterwards compared to the estimated probable structural losses, which is presented in the second part of the paper, based on a damage scenario in the referring earthquake. The applied damage scenario is based on recently developed damage probability matrices (DPMs) from Athens (Greece) damage database. The seismic risk estimation refers to 750,085 buildings situated in the extended urban region of Athens. The building exposure is categorized in five typical structural types and represents 18.80 % of the entire building stock in Greece. The last information is provided by the National Statistics Service of Greece (NSSG) according to the 2000-2001 census. The seismic input is characterized by the ratio, a g/ a o, where a g is the regional peak ground acceleration (PGA) which is evaluated from the earlier estimated research macroseismic intensities, and a o is the PGA according to the hazard map of the 2003 Greek Seismic Code. Finally, the collected investigated financial data derived from different National Services responsible for the post-earthquake crisis management concerning the repair/strengthening or replacement costs or other categories of costs for the rehabilitation of earthquake victims (construction and function of settlements for earthquake homeless, rent supports, demolitions, shorings) are used to determine the final total seismic risk factor.

  14. Essential and distinct roles of the F-box and helicase domains of Fbh1 in DNA damage repair

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    Shinagawa Hideo

    2008-03-01

    Full Text Available Abstract Background DNA double-strand breaks (DSBs are induced by exogenous insults such as ionizing radiation and chemical exposure, and they can also arise as a consequence of stalled or collapsed DNA replication forks. Failure to repair DSBs can lead to genomic instability or cell death and cancer in higher eukaryotes. The Schizosaccharomyces pombe fbh1 gene encodes an F-box DNA helicase previously described to play a role in the Rhp51 (an orthologue of S. cerevisiae RAD51-dependent recombinational repair of DSBs. Fbh1 fused to GFP localizes to discrete nuclear foci following DNA damage. Results To determine the functional roles of the highly conserved F-box and helicase domains, we have characterized fbh1 mutants carrying specific mutations in these domains. We show that the F-box mutation fbh1-fb disturbs the nuclear localization of Fbh1, conferring an fbh1 null-like phenotype. Moreover, nuclear foci do not form in fbh1-fb cells with DNA damage even if Fbh1-fb is targeted to the nucleus by fusion to a nuclear localization signal sequence. In contrast, the helicase mutation fbh1-hl causes the accumulation of Fbh1 foci irrespective of the presence of DNA damage and confers damage sensitivity greater than that conferred by the null allele. Additional mutation of the F-box alleviates the hypermorphic phenotype of the fbh1-hl mutant. Conclusion These results suggest that the F-box and DNA helicase domains play indispensable but distinct roles in Fbh1 function. Assembly of the SCFFbh1 complex is required for both the nuclear localization and DNA damage-induced focus formation of Fbh1 and is therefore prerequisite for the Fbh1 recombination function.

  15. Induction and repair of DNA damage measured by the comet assay in human T lymphocytes separated by immunomagnetic cell sorting.

    Science.gov (United States)

    Bausinger, Julia; Speit, Günter

    2014-11-01

    The comet assay is widely used in human biomonitoring to measure DNA damage in whole blood or isolated peripheral blood mononuclear cells (PBMC) as a marker of exposure to genotoxic agents. Cytogenetic assays with phytohemagglutinin (PHA)-stimulated cultured T lymphocytes are also frequently performed in human biomonitoring. Cytogenetic effects (micronuclei, chromosome aberrations, sister chromatid exchanges) may be induced in vivo but also occur ex vivo during the cultivation of lymphocytes as a consequence of DNA damage present in lymphocytes at the time of sampling. To better understand whether DNA damage measured by the comet assay in PBMC is representative for DNA damage in T cells, we comparatively investigated DNA damage and its repair in PBMC and T cells obtained by immunomagnetic cell sorting. PBMC cultures and T cell cultures were exposed to mutagens with different modes of genotoxic action and DNA damage was measured by the comet assay after the end of a 2h exposure and after 18h post-incubation. The mutagens tested were methyl methanesulfonate (MMS), (±)-anti-B[a]P-7,8-dihydrodiol-9,10-epoxide (BPDE), 4-nitroquinoline-1-oxide (4NQO), styrene oxide and potassium bromate. MMS and potassium bromate were also tested by the modified comet assay with formamido pyrimidine glycosylase (FPG) protein. The results indicate that the mutagens tested induce DNA damage in PBMC and T cells in the same range of concentrations and removal of induced DNA lesions occurs to a comparable extent. Based on these results, we conclude that the comet assay with PBMC is suited to predict DNA damage and its removal in T cells.

  16. Inflammatory cytokines regulate endothelial cell survival and tissue repair functions via NF-κB signaling

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    Kanaji N

    2011-09-01

    Full Text Available Nobuhiro Kanaji1, Tadashi Sato2, Amy Nelson3, Xingqi Wang3, YingJi Li4, Miok Kim5, Masanori Nakanishi6, Hesham Basma3, Joel Michalski3, Maha Farid3, Michael Chandler3, William Pease3, Amol Patil3, Stephen I Rennard3, Xiangde Liu31Division of Hematology, Rheumatology and Respiratory Medicine, Kagawa University, Kagawa, Japan; 2Department of Respiratory Medicine, Juntendo University School of Medicine, Tokyo, Japan; 3Pulmonary and Critical Care Medicine, University of Nebraska Medical Center, Omaha, Nebraska; 4Department of Hygiene and Public Health, Nippon Medical School, Tokyo, Japan; 5Third Department of Internal Medicine, Wakayama Medical University School of Medicine, Wakayama, Japan; 6Department of Internal Medicine, Jeju Medical College, Jeju, Republic of KoreaAbstract: Inflammation contributes to the development of fibrotic and malignant diseases. We assessed the ability of inflammatory cytokines to modulate endothelial cell survival and functions related to tissue repair/remodeling. Treatment with interleukin (IL-1ß or tumor necrosis factor (TNF-α (2 ng/mL led to human pulmonary artery endothelial cells becoming spindle-shaped fibroblast-like cells. However, immunoblot and DNA microarray showed no change in most endothelial and mesenchymal markers. In the presence of IL-1ß or TNF-α, cells were resistant to apoptosis induced by deprivation of serum and growth factor, and were more migratory. In addition, cells treated with IL-1ß or TNF-α contracted collagen gels more robustly. In contrast, transforming growth factor-ß1 did not induce these responses. RNA interference targeting nuclear factor (NF- κB p65 blocked the effects of IL-1ß or TNF-α on cell morphologic change, survival, migration, and collagen gel contraction. These results suggest that endothelial cells may contribute to tissue repair/remodeling via the NF-κB signaling in a milieu of airway inflammation.Keywords: NF-κB, IL-1ß, TNF-α, apoptosis, tissue repair

  17. Inflammatory and regenerative responses in salmonids following mechanical tissue damage and natural infection

    DEFF Research Database (Denmark)

    Ingerslev, Hans-Christian; Lunder, Tor; Nielsen, Michael Engelbrecht

    2010-01-01

    Locale responses in muscle tissue against either a sterile tissue damage or infection were compared in salmonid fish in order to examine the inflammatory responses and regeneration of tissue. From higher vertebrates both damage and infection are known to cause inflammation since DAMPs released from...... injured cells as well as PAMPs from the surface of pathogens are immunogenic. To examine this in salmonid fishes, Atlantic salmon (Salmo salar) were infected with Moritella viscosus, the causative agent of winter ulcer. Muscle tissue was sampled from infected fish at 4, 7 and 14 days post infection...... are coding for immunological factors and tissue regeneration. Locale, inflammatory responses were seen as strong up-regulation of IL-1β and IL-8 in both groups of fish, but it was more pronounced in infected fish. Expression of the toll-like receptors showed induction of TLR-5m following infection, but TLR-9...

  18. The interplay among chromatin dynamics, cell cycle checkpoints and repair mechanisms modulates the cellular response to DNA damage.

    Science.gov (United States)

    Lazzaro, Federico; Giannattasio, Michele; Muzi-Falconi, Marco; Plevani, Paolo

    2007-06-01

    Cells are continuously under the assault of endogenous and exogenous genotoxic stress that challenges the integrity of DNA. To cope with such a formidable task cells have evolved surveillance mechanisms, known as checkpoints, and a variety of DNA repair systems responding to different types of DNA lesions. These lesions occur in the context of the chromatin structure and, as expected for all DNA transactions, the cellular response to DNA damage is going to be influenced by the chromatin enviroment. In this review, we will discuss recent studies implicating chromatin remodelling factors and histone modifications in the response to DNA double-strand breaks (DSBs) and in checkpoint activation in response to UV lesions.

  19. How Can Nanotechnology Help to Repair the Body? Advances in Cardiac, Skin, Bone, Cartilage and Nerve Tissue Regeneration

    Directory of Open Access Journals (Sweden)

    Juan Antonio Marchal

    2013-03-01

    Full Text Available Nanotechnologists have become involved in regenerative medicine via creation of biomaterials and nanostructures with potential clinical implications. Their aim is to develop systems that can mimic, reinforce or even create in vivo tissue repair strategies. In fact, in the last decade, important advances in the field of tissue engineering, cell therapy and cell delivery have already been achieved. In this review, we will delve into the latest research advances and discuss whether cell and/or tissue repair devices are a possibility. Focusing on the application of nanotechnology in tissue engineering research, this review highlights recent advances in the application of nano-engineered scaffolds designed to replace or restore the followed tissues: (i skin; (ii cartilage; (iii bone; (iv nerve; and (v cardiac.

  20. Safety of intra-articular use of atelocollagen for enhanced tissue repair.

    Science.gov (United States)

    Magarian, Elise M; Vavken, Patrick; Connolly, Susan A; Mastrangelo, Ashley N; Murray, Martha M

    2012-01-01

    Collagen is an important biomaterial in intra-articular tissue engineering, but there are unanswered questions about its safety. We hypothesize that the addition of type-I-collagen for primary repair of the Anterior Cruciate Ligament (ACL) might result in a local and systemic reaction in a porcine model after 15 weeks as demonstrated by joint effusion, synovial thickening, elevated intraarticular and systemic leukocyte counts. Further, this reaction might be aggravated by the addition of a platelet concentrate. Eighteen porcine ACLs were transected and repaired with either sutures (n=6), a collagen sponge (n=6), or a collagen-platelet-composite (CPC; n=6). Twelve intact contralateral knees served as controls (n=12). No significant synovial thickening or joint effusion was seen in the collagen-treated knees. Synovial fluid leukocyte counts showed no significant differences between surgically treated and intact knees, and no differences were seen in leukocyte counts of the peripheral blood. The addition of a platelet concentrate to the knee joint resulted in lower serum levels of IL-1β, but serum levels of TNF-α were not significantly different between groups. In conclusion, the presence of collagen, with or without added platelets, did not increase the local or systemic inflammatory reactions following surgery, suggesting that Type I collagen is safe to use in the knee joint.

  1. Tissue damage in salmonids caused by Halisidota argentata Packard

    Science.gov (United States)

    1956-01-01

    During the histological examination of a collection of wild and hatchery salmonids, a peculiar foreign body was occasionally observed in various organs, particularly in the viscera. These objects, usually accompanied by a focal inflammation, were observed in 10 of 75 samples of wild trout and salmon collected in Oregon and Washington and were believed to represent an unknown type of parasitism. Their identity remained obscure until a massive concentration was observed in the tissues of wild coho salmon, (Oncorhynchus kisutch), from Minter Creek on the Olympic peninsula of Washington and in hatchery coho salmon from the Minter Creek Biological Station. The distribution of the structures suggested the intestinal tract as a point of origin. Subsequent stomach examinations revealed small, partially digested insect fragments with many long, spine-covered hairs. The insects were identified as second or third instars of the lepidopteran larvae, Halisidota argentata Packard. The spine-covered hairs penetrated the stomach wall and produced the observed lesions by working in an apparent porcupine quill-fashion throughout the body of the fish.

  2. DNA adduct kinetics in reproductive tissues of DNA repair proficient and deficient male mice after oral exposure to benzo(a)pyrene.

    Science.gov (United States)

    Verhofstad, Nicole; van Oostrom, Conny Th M; van Benthem, Jan; van Schooten, Frederik J; van Steeg, Harry; Godschalk, Roger W L

    2010-03-01

    Benzo(a)pyrene (B[a]P) can induce somatic mutations, whereas its potential to induce germ cell mutations is unclear. There is circumstantial evidence that paternal exposure to B[a]P can result in germ cell mutations. Since DNA adducts are thought to be a prerequisite for B[a]P induced mutations, we studied DNA adduct kinetics by (32)P-postlabeling in sperm, testes and lung tissues of male mice after a single exposure to B[a]P (13 mg/kg bw, by gavage). To investigate DNA adduct formation at different stages of spermatogenesis, mice were sacrificed at Day 1, 4, 7, 10, 14, 21, 32, and 42 after exposure. In addition, DNA repair deficient (Xpc(-/-)) mice were used to study the contribution of nucleotide excision repair in DNA damage removal. DNA adducts were detectable with highest levels in lung followed by sperm and testis. Maximum adduct levels in the lung and testis were observed at Day 1 after exposure, while adduct levels in sperm reached maximum levels at approximately 1 week after exposure. Lung tissue and testis of Xpc(-/-) mice contained significantly higher DNA adduct levels compared to wild type (Wt) mice over the entire 42 day observation period (P adduct half-life between Xpc(-/-) and Wt mice were only observed in testis. In sperm, DNA adduct levels were significantly higher in Xpc(-/-) mice than in Wt mice only at Day 42 after exposure (P = 0.01). These results indicate that spermatogonia and testes are susceptible for the induction of DNA damage and rely on nucleotide excision repair for maintaining their genetic integrity.

  3. Checkpoint Kinase ATR Promotes Nucleotide Excision Repair of UV-induced DNA Damage via Physical Interaction with Xeroderma Pigmentosum Group A*

    Science.gov (United States)

    Shell, Steven M.; Li, Zhengke; Shkriabai, Nikolozi; Kvaratskhelia, Mamuka; Brosey, Chris; Serrano, Moises A.; Chazin, Walter J.; Musich, Phillip R.; Zou, Yue

    2009-01-01

    In response to DNA damage, eukaryotic cells activate a series of DNA damage-dependent pathways that serve to arrest cell cycle progression and remove DNA damage. Coordination of cell cycle arrest and damage repair is critical for maintenance of genomic stability. However, this process is still poorly understood. Nucleotide excision repair (NER) and the ATR-dependent cell cycle checkpoint are the major pathways responsible for repair of UV-induced DNA damage. Here we show that ATR physically interacts with the NER factor Xeroderma pigmentosum group A (XPA). Using a mass spectrometry-based protein footprinting method, we found that ATR interacts with a helix-turn-helix motif in the minimal DNA-binding domain of XPA where an ATR phosphorylation site (serine 196) is located. XPA-deficient cells complemented with XPA containing a point mutation of S196A displayed a reduced repair efficiency of cyclobutane pyrimidine dimers as compared with cells complemented with wild-type XPA, although no effect was observed for repair of (6-4) photoproducts. This suggests that the ATR-dependent phosphorylation of XPA may promote NER repair of persistent DNA damage. In addition, a K188A point mutation of XPA that disrupts the ATR-XPA interaction inhibits the nuclear import of XPA after UV irradiation and, thus, significantly reduced DNA repair efficiency. By contrast, the S196A mutation has no effect on XPA nuclear translocation. Taken together, our results suggest that the ATR-XPA interaction mediated by the helix-turn-helix motif of XPA plays an important role in DNA-damage responses to promote cell survival and genomic stability after UV irradiation. PMID:19586908

  4. Detection of abnormalities in the superficial zone of cartilage repaired using a tissue engineered construct derived from synovial stem cells.

    Science.gov (United States)

    Ando, Wataru; Fujie, Hiromichi; Moriguchi, Yu; Nansai, Ryosuke; Shimomura, Kazunori; Hart, David A; Yoshikawa, Hideki; Nakamura, Norimasa

    2012-09-28

    The present study investigated the surface structure and mechanical properties of repair cartilage generated from a tissue engineered construct (TEC) derived from synovial mesenchymal stem cells at six months post-implantation compared to those of uninjured cartilage. TEC-mediated repair tissue was cartilaginous with Safranin O staining, and had comparable macro-scale compressive properties with uninjured cartilage. However, morphological assessments revealed that the superficial zone of TEC-mediated tissue was more fibrocartilage-like, in contrast to the middle or deep zones that were more hyaline cartilage-like with Safranin O staining. Histological scoring of the TEC-mediated tissue was significantly lower in the superficial zone than in the middle and deep zones. Scanning electron microscopy showed a thick tangential bundle of collagen fibres at the most superficial layer of uninjured cartilage, while no corresponding structure was detected at the surface of TEC-mediated tissue. Immunohistochemical analysis revealed that PRG4 was localised in the superficial area of uninjured cartilage, as well as the TEC-mediated tissue. Friction testing showed that the lubrication properties of the two tissues was similar, however, micro-indentation analysis revealed that the surface stiffness of the TEC-repair tissue was significantly lower than that of uninjured cartilage. Permeability testing indicated that the TEC-mediated tissue exhibited lower water retaining capacity than did uninjured cartilage, specifically at the superficial zone. Thus, TEC-mediated tissue exhibited compromised mechanical properties at the superficial zone, properties which need improvement in the future for maintenance of long term repair cartilage integrity.

  5. Detection of abnormalities in the superficial zone of cartilage repaired using a tissue engineered construct derived from synovial stem cells

    Directory of Open Access Journals (Sweden)

    W Ando

    2012-09-01

    Full Text Available The present study investigated the surface structure and mechanical properties of repair cartilage generated from a tissue engineered construct (TEC derived from synovial mesenchymal stem cells at six months post-implantation compared to those of uninjured cartilage. TEC-mediated repair tissue was cartilaginous with Safranin O staining, and had comparable macro-scale compressive properties with uninjured cartilage. However, morphological assessments revealed that the superficial zone of TEC-mediated tissue was more fibrocartilage-like, in contrast to the middle or deep zones that were more hyaline cartilage-like with Safranin O staining. Histological scoring of the TEC-mediated tissue was significantly lower in the superficial zone than in the middle and deep zones. Scanning electron microscopy showed a thick tangential bundle of collagen fibres at the most superficial layer of uninjured cartilage, while no corresponding structure was detected at the surface of TEC-mediated tissue. Immunohistochemical analysis revealed that PRG4 was localised in the superficial area of uninjured cartilage, as well as the TEC-mediated tissue. Friction testing showed that the lubrication properties of the two tissues was similar, however, micro-indentation analysis revealed that the surface stiffness of the TEC-repair tissue was significantly lower than that of uninjured cartilage. Permeability testing indicated that the TEC-mediated tissue exhibited lower water retaining capacity than did uninjured cartilage, specifically at the superficial zone. Thus, TEC-mediated tissue exhibited compromised mechanical properties at the superficial zone, properties which need improvement in the future for maintenance of long term repair