Search results for "Deoxyribonuclease I"

Induction of heme oxygenase-1 and adaptive protection against the induction of DNA damage after hyperbaric oxygen treatment.

2000

Hyperbaric oxygen (HBO) treatment of human subjects (i.e. exposure to 100% oxygen at a pressure of 2.5 ATA for a total period of 3 x 20 min) caused clear and reproducible DNA damage in lymphocytes, as detected with the comet assay (single cell gel electrophoresis). Induction of DNA damage was found only after the first HBO exposure and not after further treatments of the same individuals. Furthermore, blood taken 24 h after HBO treatment was significantly protected against the induction of DNA damage by hydrogen peroxide (H(2)O(2)) in vitro, indicating that adaptation occurred due to induction of antioxidant defenses. The cells were not significantly protected against the genotoxic effects …

Long-time expression of DNA repair enzymes MGMT and APE in human peripheral blood mononuclear cells.

2001

The DNA repair enzymes O6-methylguanine-DNA methyltransferase (MGMT) and apurinic/apyrimidinic endonuclease (APE, also known as Ref-1) play an important role in cellular defense against the mutagenic and carcinogenic effects of DNA-damaging agents. Cells with low enzyme activity are more sensitive to induced DNA damage and may confer a higher carcinogenic risk to the individuals in question. To study the level of variability of MGMT and APE expression in human, we analyzed in a long-time study MGMT and APE expression in peripheral blood mononuclear cells (PBMC) from healthy individuals. The data revealed high inter- and intraindividual variability of MGMT but not of APE. For MGMT, the inter…

Inhalation solutions: which one are allowed to be mixed? Physico-chemical compatibility of drug solutions in nebulizers.

2006

AbstractTherapy of chronic respiratory diseases often involves inhalation therapy with nebulizers. Patients often attempt to shorten the time consuming administration procedure by mixing drug solutions/suspensions for simultaneous inhalation. This article considers the issue of physico-chemical compatibility of admixtures of drug solutions/suspensions in nebulizers.A search of databases, prescribing information and primary literature was conducted to locate literature concerning the physico-chemical compatibility of inhalation solutions/suspensions. This was supplemented by telephone interviews.Admixtures of albuterol with ipratropium and/or cromolyn, of albuterol and budesonide, or tobramy…

DNA oxidation products determined with repair endonucleases in mammalian cells: Types, basal levels and influence of cell proliferation

1999

Purified repair endonucleases such as Fpg protein, endonuclease III and IV allow a very sensitive quantification of various types of oxidative DNA modifications in mammalian cells. By means of these assays, the numbers of base modifications sensitive to Fpg protein, which include 8-hydroxyguanine (8-oxoG), were determined to be less than 0.3 per 10(6) bp in several types of untreated cultured mammalian cells and human lymphocytes and less than 10 per 10(6) bp in mitochondrial DNA from rat and porcine liver. Oxidative 5,6-dihydropyrimidine derivatives sensitive to endonuclease III and sites of base loss sensitive to endonuclease IV or exonuclease III were much less frequent than Fpg-sensitiv…

Influences of histone deacetylase inhibitors and resveratrol on DNA repair and chromatin compaction

2013

Accessibility of DNA is a prerequisite for both DNA damage and repair. Therefore, the chromatin structure is expected to have major impact on both processes, with opposite consequences for the stability of the genome. To analyse the influence of chromatin compaction on the generation and repair of various types of DNA modifications, we modulated the global chromatin structure of AS52 Chinese hamster ovary cells and HeLa cells by treatment with either histone deacetylase inhibitors or resveratrol and measured the repair kinetics of (i) pyrimidine dimers induced by ultraviolet B, (ii) oxidised purines generated by photosensitisation and (iii) single-strand breaks induced by H2O2, using an alk…

Unraveling the interaction between doxorubicin and DNA origami nanostructures for customizable chemotherapeutic drug release

2021

We thank Dr H. Häkkänen for technical assistance and S. Julin for the 24HB DNA origami design. We acknowledge the provision of facilities and technical support by Aalto University Bioeconomy Facilities and OtaNano – Nanomicroscopy Center (Aalto-NMC). The research was carried out under the Academy of Finland Centres of Excellence Programme (2014–2019). Academy of Finland [308578 to M.A.K.]; Deutsche Forschungsgemeinschaft [Emmy Noether Programme to A.H.-J., SFB1032 (Project A06) to T.L.]; Emil Aaltonen Foundation [to H.I. and V.L.]; Jane and Aatos Erkko Foundation [to J.A.I. and V.L.]; Sigrid Jusélius Foundation [to V.L.]; Vilho, Yrjö and Kalle Väisälä Foundation of the Finnish Academy of Sc…

2021

AbstractDoxorubicin (DOX) is a common drug in cancer chemotherapy, and its high DNA-binding affinity can be harnessed in preparing DOX-loaded DNA nanostructures for targeted delivery and therapeutics. Although DOX has been widely studied, the existing literature of DOX-loaded DNA-carriers remains limited and incoherent. Here, based on an in-depth spectroscopic analysis, we characterize and optimize the DOX loading into different 2D and 3D scaffolded DNA origami nanostructures (DONs). In our experimental conditions, all DONs show similar DOX binding capacities (one DOX molecule per two to three base pairs), and the binding equilibrium is reached within seconds, remarkably faster than previou…

Stability of PEI–DNA and DOTAP–DNA complexes: effect of alkaline pH, heparin and serum

2001

Abstract DNA complexes formed with nonviral vectors such as polyethylenimine (PEI) or 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP) are widely used in gene therapy. These complexes prevent the interaction of DNA with the fluorescent probes usually employed to quantify DNA. We thus studied the procedures for DNA quantification from DNA complexes as well as their stability in the presence of DNase or mouse, rat and human sera. Release of the DNA from its complexes was accomplished by increasing the pH of the medium (from 7.3 to 13.4) or by adding heparin. The stability against degradation was tested in vitro, by incubating the complexes at 37°C in the presence of DNase I and sera from the …

Autoregulation of NFATc1/A Expression Facilitates Effector T Cells to Escape from Rapid Apoptosis

2002

AbstractThreshold levels of individual NFAT factors appear to be critical for apoptosis induction in effector T cells. In these cells, the short isoform A of NFATc1 is induced to high levels due to the autoregulation of the NFATc1 promoter P1 by NFATs. P1 is located within a CpG island in front of exon 1, represents a DNase I hypersensitive chromatin site, and harbors several sites for binding of inducible transcription factors, including a tandemly arranged NFAT site. A second promoter, P2, before exon 2, is not controlled by NFATs and directs synthesis of the longer NFATc1/B+C isoforms. Contrary to other NFATs, NFATc1/A is unable to promote apoptosis, suggesting that NFATc1/A enhances eff…

DNase I sensitivity of the chromatin of the yeast SUC2 gene for invertase.

1986

The DNase I sensitivity of chromatin of the yeast SUC2 gene, which encodes two forms of invertase, has been studied both in the genome and in a multicopy plasmid carrying the gene and its flaking sequences. Whereas little if any difference in the DNase I sensitivity of the flanking regions was found between the repressed and the derepressed states, derepression of the gene was accompanied by a large increase in the sensitivity of the transcribed region. A well-defined DNase I hypersensitive site was found centered at approximately 120 bp downstream from the end of the coding region. This site seems to be flanked in the 3' non-coding region by strictly positioned nucleosomes, and the structu…