Search results for "DAMAGE"
showing 10 items of 1289 documents
A nanodosimetric model of radiation-induced clustered DNA damage yields
2010
International audience; We present a nanodosimetric model for predicting the yield of double strand breaks (DSBs) and non-DSB clustered damages induced in irradiated DNA. The model uses experimental ionization cluster size distributions measured in a gas model by an ion counting nanodosimeter or, alternatively, distributions simulated by a Monte Carlo track structure code developed to simulate the nanodosimeter. The model is based on a straightforward combinatorial approach translating ionizations, as measured or simulated in a sensitive gas volume, to lesions in a DNA segment of one-two helical turns considered equivalent to the sensitive volume of the nanodosimeter. The two model paramete…
Molecular Basis of DNA Photodimerization: Intrinsic Production of Cyclobutane Cytosine Dimers
2008
Based on CASPT2 results, the present contribution establishes for the first time that cytosine photodimer formation (CC) is mediated along the triplet and singlet manifold by a singlet-triplet crossing, (T1/S0)X, and by a conical intersection, (S1/S0)CI, respectively. The former can be accessed in a barrierless way from a great variety of photochemical avenues and exhibits a covalent single bond between the ethene C6-C6' carbon atoms of each monomer. The efficiency of the stepwise triplet mechanism, however, would be modulated by the effectiveness of the intersystem crossing mechanism. The results provide the grounds for the understanding of the potential photogenotoxicity of endogenous and…
When and how do hospital nurses cope with daily stressors? A multilevel study
2020
BackgroundDuring their workday, nurses face a variety of stressors that are dealt with using different coping strategies. One criticism of the contextual models of work stress is that they fail to focus on individual responses like coping with stress. Neverthless, little is know about the momentary determinants of coping in nurses.ObjectivesTo identify the momentary predictors of problem-focused approaching coping and emotion-focused approaching coping, as well as those for seeking social support and refusal coping strategies, during the working day in nurses.DesignThis study uses descriptive, correlational, two-level design with repeated measures.SettingsWards of two University hospitals.P…
Non-coding RNAs at the Eukaryotic rDNA Locus: RNA–DNA Hybrids and Beyond
2019
The human ribosomal DNA (rDNA) locus encodes a variety of long non-coding RNAs (lncRNAs). Among them, the canonical ribosomal RNAs that are the catalytic components of the ribosomes, as well as regulatory lncRNAs including promoter-associated RNAs (pRNA), stress-induced promoter and pre-rRNA antisense RNAs (PAPAS), and different intergenic spacer derived lncRNA species (IGSRNA). In addition, externally encoded lncRNAs are imported into the nucleolus, which orchestrate the complex regulation of the nucleolar state in normal and stress conditions via a plethora of molecular mechanisms. This review focuses on the triplex and R-loop formation aspects of lncRNAs at the rDNA locus in yeast and hu…
The endoperoxide ascaridol shows strong differential cytotoxicity in nucleotide excision repair-deficient cells
2011
Targeting synthetic lethality in DNA repair pathways has become a promising anti-cancer strategy. However little is known about such interactions with regard to the nucleotide excision repair (NER) pathway. Therefore, cell lines with a defect in the NER genes ERCC6 or XPC and their normal counterparts were screened with 53 chemically defined phytochemicals isolated from plants used in traditional Chinese medicine for differential cytotoxic effects. The screening revealed 12 drugs that killed NER-deficient cells more efficiently than proficient cells. Five drugs were further analyzed for IC50 values, effects on cell cycle distribution, and induction of DNA damage. Ascaridol was the most effe…
Displacement Defect Formation in Complex Oxide Crystals under Irradiation
2000
The work is devoted to an analysis of formation processes of the radiation displacement defects (RDDs) and colour centres (CCs) in complex oxide crystals under irradiation. The calculation results on: the displacement process simulation as well as an analysis of the RDD and CC accumulation kinetics are presented. New experimental results on additional absorption spectra induced by neutron irradiation of LiNbO(3) (LNO) crystals doped with Fe and Cr and YAlO(3) (YAP) crystals doped with Nd and Er as well are presented. Dose dependencies of the additional absorption are compared and their peculiarities are discussed. The obtained results confirm that CCs causing the irradiation induced absorpt…
The ras-related small GTP-binding protein RhoB is immediate-early inducible by DNA damaging treatments.
1995
The low molecular weight GTP-binding proteins RhoA, RhoB, and RhoC are characterized as specific substrates for the ADP-ribosyltransferase C3 from Clostridium botulinum and are supposed to be involved in the organization of the microfilamental network and transformation. rhoB is known to be immediate-early inducible by growth factors and protein-tyrosine kinases. Since increasing evidence indicates overlapping of growth factor- and UV-induced signal pathways, we studied the effect of UV light and other genotoxic agents on early rhoB transcription. Within 30 min after UV irradiation of NIH3T3 cells, the amount of rhoB mRNA increased 3-4-fold. Elevated rhoB mRNA was accompanied by an increase…
The radiosensitization effect of titanate nanotubes as a new tool in radiation therapy for glioblastoma: A proof-of-concept
2013
Abstract Background and purpose One of the new challenges to improve radiotherapy is to increase the ionizing effect by using nanoparticles. The interest of titanate nanotubes (TiONts) associated with radiotherapy was evaluated in two human glioblastoma cell lines (SNB-19 and U87MG). Materials and methods Titanate nanotubes were synthetized by the hydrothermal treatment of titanium dioxide powder in a strongly basic NaOH solution. The cytotoxicity of TiONts was evaluated on SNB-19 and U87MG cell lines by cell proliferation assay. The internalization of TiONts was studied using Transmission Electron Microscopy (TEM). Finally, the effect of TiONts on cell radiosensitivity was evaluated using …
DANNO, RISARCIMENTO E RICONOSCIMENTO DELL’“ALTRO” NELLA GESTIONE DEI CONFLITTI IN OMERO
2019
Atto ingiusto, reato? Nel mondo omerico abbiamo a che fare: 1. con atasthalìai (in Omero solo al plurale), cioè con “eccessi-volontari-e-consapevoli fondati-sulla-fiducia nella-propria-forza/capacità/potere”, di cui si è responsabili (mentre non si è responsabili o si è innocenti se si obbedisce a cause materiali/umane di forza maggiore), o 2. con àte, l’offuscamento mentale che rovina se stessi e a volte gli altri e che si è avuto per propria imprudenza, mancanza di calcolo o perché gli dei puniscono di una precedente offesa fatta loro. In quest’ultimo caso, si può rimediare oppure bisogna aspettare i tempi della divinità. Nel caso di offese ad altri uomini, bisogna risarcire materialmente…
COVID-19 pandemic, mechanical reperfusion and 30-day mortality in ST elevation myocardial infarction
2022
ObjectiveThe initial data of the International Study on Acute Coronary Syndromes - ST Elevation Myocardial Infarction COVID-19 showed in Europe a remarkable reduction in primary percutaneous coronary intervention procedures and higher in-hospital mortality during the initial phase of the pandemic as compared with the prepandemic period. The aim of the current study was to provide the final results of the registry, subsequently extended outside Europe with a larger inclusion period (up to June 2020) and longer follow-up (up to 30 days).MethodsThis is a retrospective multicentre registry in 109 high-volume primary percutaneous coronary intervention (PPCI) centres from Europe, Latin America, S…