scholarly journals N-Formamido Group Formed in the Place of Thymine Fragment under Gamma Irradiation of DNA. Rapid Indirect Method of Evaluation both in vitro and in vivo Conditions

1979 ◽  
Vol 20 (2) ◽  
pp. 166-173 ◽  
Author(s):  
A. BONICEL ◽  
R. TEOULE
Keyword(s):  
Gamma Irradiation ◽  
Indirect Method ◽  
Method Of Evaluation

scholarly journals ERCC1-XPF Endonuclease Facilitates DNA Double-Strand Break Repair

2008 ◽  
Vol 28 (16) ◽  
pp. 5082-5092 ◽  
Author(s):  
Anwaar Ahmad ◽  
Andria Rasile Robinson ◽  
Anette Duensing ◽  
Ellen van Drunen ◽  
H. Berna Beverloo ◽  
...  
Keyword(s):  
Gamma Irradiation ◽  
Excision Repair ◽  
Strand Break ◽  
Dna Lesions ◽  
End Joining ◽  
Dsb Repair ◽  
Large Deletions ◽  
Mutant Cells

ABSTRACT ERCC1-XPF endonuclease is required for nucleotide excision repair (NER) of helix-distorting DNA lesions. However, mutations in ERCC1 or XPF in humans or mice cause a more severe phenotype than absence of NER, prompting a search for novel repair activities of the nuclease. In Saccharomyces cerevisiae, orthologs of ERCC1-XPF (Rad10-Rad1) participate in the repair of double-strand breaks (DSBs). Rad10-Rad1 contributes to two error-prone DSB repair pathways: microhomology-mediated end joining (a Ku86-independent mechanism) and single-strand annealing. To determine if ERCC1-XPF participates in DSB repair in mammals, mutant cells and mice were screened for sensitivity to gamma irradiation. ERCC1-XPF-deficient fibroblasts were hypersensitive to gamma irradiation, and γH2AX foci, a marker of DSBs, persisted in irradiated mutant cells, consistent with a defect in DSB repair. Mutant mice were also hypersensitive to irradiation, establishing an essential role for ERCC1-XPF in protecting against DSBs in vivo. Mice defective in both ERCC1-XPF and Ku86 were not viable. However, Ercc1 −/− Ku86 −/− fibroblasts were hypersensitive to gamma irradiation compared to single mutants and accumulated significantly greater chromosomal aberrations. Finally, in vitro repair of DSBs with 3′ overhangs led to large deletions in the absence of ERCC1-XPF. These data support the conclusion that, as in yeast, ERCC1-XPF facilitates DSB repair via an end-joining mechanism that is Ku86 independent.

In Vitro Evaluation of Drug Solubility and Gamma Irradiation on the Release of Betamethasone under Simulated In Vivo Conditions

2007 ◽  
Vol 22 (4) ◽  
pp. 443-459 ◽  
Author(s):  
Mohammad Rafienia ◽  
Hamid Mirzadeh ◽  
Hamid Mirzadeh ◽  
Hamid Mobedi ◽  
Ahmad Jamshidi
Keyword(s):  
Gamma Irradiation ◽  
Drug Solubility ◽  
In Vitro Evaluation

scholarly journals Graphene Oxide and Reduced Graphene Oxide Exhibit Cardiotoxicity Through the Regulation of Lipid Peroxidation, Oxidative Stress, and Mitochondrial Dysfunction

2021 ◽  
Vol 9 ◽  
Author(s):  
Jian Zhang ◽  
Hong-Yan Cao ◽  
Ji-Qun Wang ◽  
Guo-Dong Wu ◽  
Lin Wang
Keyword(s):  
Oxidative Stress ◽  
Lipid Peroxidation ◽  
Graphene Oxide ◽  
Membrane Potential ◽  
Gamma Irradiation ◽  
Cell Apoptosis ◽  
Mitochondrial Membrane ◽  
H9c2 Cells

ObjectiveGraphene has been widely used for various biological and biomedical applications due to its unique physiochemical properties. This study aimed to evaluate the cardiotoxicity of graphene oxide (GO) and reduced GO (rGO) in vitro and in vivo, as well as to investigate the underlying toxicity mechanisms.MethodsGO was reduced by gamma irradiation to prepare rGO and then characterized by UV/visible light absorption spectroscopy. Rat myocardial cells (H9C2) were exposed to GO or rGO with different absorbed radiation doses. The in vitro cytotoxicity was evaluated by MTT assay, cell apoptosis assay, and lactate dehydrogenase (LDH) activity assay. The effects of GO and rGO on oxidative damage and mitochondrial membrane potential were also explored in H9C2 cells. For in vivo experiments, mice were injected with GO or rGO. The histopathological changes of heart tissues, as well as myocardial enzyme activity and lipid peroxidation indicators in heart tissues were further investigated.ResultsrGO was developed from GO following different doses of gamma irradiation. In vitro experiments in H9C2 cells showed that compared with control cells, both GO and rGO treatment inhibited cell viability, promoted cell apoptosis, and elevated the LDH release. With the increasing radiation absorbed dose, the cytotoxicity of rGO gradually increased. Notably, GO or rGO treatment increased the content of ROS and reduced the mitochondrial membrane potential in H9C2 cells. In vivo experiments also revealed that GO or rGO treatment damaged the myocardial tissues and changed the activities of several myocardial enzymes and the lipid peroxidation indicators in the myocardial tissues.ConclusionGO exhibited a lower cardiotoxicity than rGO due to the structure difference, and the cardiotoxicity of GO and rGO might be mediated by lipid peroxidation, oxidative stress, and mitochondrial dysfunction.

Cytoarchitecture of the Xenopus thymus following gamma-irradiation

Development ◽  
1987 ◽  
Vol 100 (1) ◽  
pp. 95-105
Author(s):  
JH Russ ◽  
JD Horton
Keyword(s):  
Gamma Irradiation ◽  
Tolerance Induction ◽  
Cell Types ◽  
Whole Body ◽  
Thymic Stromal Cells ◽  
Normal Architecture

This paper describes in vitro and in vivo attempts to deplete the 4- to 8-month-old Xenopus laevis (J strain) thymus of its lymphocyte compartment. Gamma irradiation (2-3000 rad) of the excised thymus, followed by two weeks in organ culture, is effective in removing lymphocytes, but causes drastic reduction in size and loss of normal architecture. In contrast, in vivo whole-body irradiation (3000 rad) and subsequent in situ residence for 8-14 days proves successful in providing a lymphocyte-depleted froglet thymus without loss of cortical and medullary zones. In vivo-irradiated thymuses are about half normal size, lack cortical lymphocytes, but still retain some medullary thymocytes; they show no signs of lymphocyte regeneration when subsequently organ cultured for 2 weeks. Light microscopy of 1 micron, plastic-embedded sections and electron microscopy reveal that a range of thymic stromal cell types are retained and that increased numbers of cysts, mucous and myoid cells are found in the thymus following whole-body irradiation. In vivo-irradiated thymuses are therefore suitable for implantation studies exploring the role of thymic stromal cells in tolerance induction of differentiating T lymphocytes.

Laboratory studies on the effect of gamma radiation on Erwinia amylovora survival on apple fruit

1986 ◽  
Vol 32 (10) ◽  
pp. 787-790 ◽  
Author(s):  
W. J. Janisiewicz ◽  
T. van der Zwet ◽  
P. B. Jahrling
Keyword(s):  
Gamma Irradiation ◽  
Erwinia Amylovora ◽  
Natural Populations ◽  
Apple Fruit ◽  
Test Tube ◽  
Bacterial Strains ◽  
Irradiation Treatment ◽  
Viable Bacteria

Susceptibility of Erwinia amylovora to gamma irradiation was determined in vitro on test tube cultures and in vivo on apples and pears. Bacterial strains differed in susceptibility to irradiation. Higher doses of irradiation (ca. 80 krad (1 krad = 10 Gy)) were needed to kill the bacterium on fruit compared with test tube cultures (from 20 to more than 50 krad). Fruit with natural populations of E. amylovora collected from a severely blighted orchard, exposed to doses of 140 krad, still contained viable bacteria. Surviving E. amylovora were pathogenic to green 'Bartlett' pears. Five radiation-sensitizing chemicals (used previously against different pathogens on other commodities) were tested against E. amylovora. N-Ethylmaleimide sensitized the bacteium to gamma irradiation. Treatment of natural populations of the bacterium on apples with N-ethylmaleimide eliminated E. amylovora from the apple surface with a gamma irradiation dose one-third lower than the maximum rate tolerable by fruit.

Decontamination of Mikania glomerata Leaves by Gamma Irradiation: Coumarin Determination by HPLC-DAD, Microbiological Control and Genotoxicological Studies

Planta Medica ◽  
2017 ◽  
Vol 84 (01) ◽  
pp. 65-72
Author(s):  
Marcos Gouvêa ◽  
Samara Ferreira-Machado ◽  
Thalita da Silva ◽  
Julien Lima ◽  
Cláudio Lau ◽  
...  
Keyword(s):  
Gamma Irradiation ◽  
Bone Marrow Cells ◽  
Micronucleus Test ◽  
Raw Material ◽  
In Vivo Models ◽  
Production Chain ◽  
Microbiological Control ◽  
Mikania Glomerata

AbstractGamma irradiation as a decontaminating physical agent could be an important tool in the production chain of herbal medicines by improving the microbiological quality of raw materials and the safety of final products. This study was undertaken to investigate the genotoxic potential and eventual chemical modifications of a batch of Mikania glomerata raw material decontaminated by different doses of gamma irradiation (2.0, 3.5, and 5.0 kGy), using a cesium-137 source. DNA damage was assessed in vitro by agarose gel electrophoresis in regard to double-chain breaks of plasmid pUC 9.1 DNA and in vivo by micronucleus test in bone marrow cells of Wistar rats. Cytotoxicity in bone marrows was assessed by scoring polychromatic and normochromatic erythrocytes ratio. An HPLC-DAD method was adapted and validated for the enhancement of coumarin selectivity from the other matrix constituents. The microbial load was satisfactorily reduced, leading to sterilization at the highest dose. Genotoxic and cytotoxic effects were not increased in the in vitro and in vivo models. The concentration of coumarin and the chromatographic profiles of the hydroalcoholic plant extracts (ethanol 70% v/v) were not modified after such process. Therefore, this work suggests that gamma irradiation of M. glomerata raw material is suitable and safe for microbiological control purposes at the employed doses.

Screening for supra-additive effects of cytotoxic drugs and gamma irradiation in an in vitro model for hepatocellular carcinoma

2004 ◽  
Vol 82 (2) ◽  
pp. 146-152 ◽  
Author(s):  
B Lambert ◽  
L De Ridder ◽  
G Slegers ◽  
V de Gelder ◽  
R A Dierckx ◽  
...  
Keyword(s):  
Hepatocellular Carcinoma ◽  
Gamma Irradiation ◽  
In Vitro Model ◽  
Palliative Therapy ◽  
Cytotoxic Drugs ◽  
Treatment Modalities ◽  
Additive Effects ◽  
Vitro Model

Hepatocellular carcinoma (HCC) is one of the most common malignancies in the world. A wide variety of treatment modalities is available for palliative therapy of HCC, although there is no strong evidence that these treatments can have a significant impact on survival. The aim of this work was to screen cytotoxic drugs relevant in the treatment of HCC for enhancement of the effect of irradiation in an in vitro model. As the majority of patients presenting with HCC suffer reduced liver function, attention was paid to low-dose effects of the cytotoxic drugs tested. To reflect this situation in vivo, multicellular tumor aggregates or "spheroids" of HepG2 cells were cultured and exposed to gamma irradiation alone or in combination with cisplatin for 4 h, gemcitabin for 4 or 24 h, or 5-fluorouracil for 4 h. In one experiment, the spheroids were cultured for 4 weeks in multiwell plates that allowed adhesion. Measurement of two-dimensional spheroid outgrowth was made every week for each spheroid. This kind of growth depends on the proliferation and motility of the cells that form the spheroid. In a second experiment, toxicity was evaluated by comparative growth curves by means of a three-dimensional growth assay and by histology. Supra-additive effects lasting for 4 weeks were observed for all drugs tested in combination with a gamma irradiation of 10 Gy.Key words: hepatocellular carcinoma, cisplatin, gemcitabine, 5-fluorouracil, gamma irradiation.

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