Search results for "Radiosensitivity"

showing 3 items of 23 documents

Lack of correlation between apoptosis and DNA single-strand breaks in X-irradiated human peripheral blood mononuclear cells in the course of ageing

1998

The dependence on age of both the basal and the X-radiation-induced levels of apoptosis was examined in human peripheral blood mononuclear cells (PBMC). In the same samples, the base value and the extent of induced DNA single-strand breaks were determined, using a sensitive and fast microplate assay. PBMC were isolated from blood of donors of various age groups (20-30, 40-60 and > 70 years of age) and X-irradiated ex vivo using a 6 MV linear accelerator to give a total exposure of 4 Gy. The mean basal levels of apoptosis in PBMC from donors in the 40-60 year age group and the > 70 year age group were found to be only slightly higher (by 20-10%) compared to that of the 20-30 year age group, …

SenescenceAgingProgrammed cell deathDNA damageX-RaysDNA Single-StrandedApoptosisBiologyPeripheral blood mononuclear cellAndrologyBlood cellmedicine.anatomical_structureApoptosisAgeingImmunologyLeukocytes MononuclearmedicineHumansRadiation-induced apoptosis; T-cells; Intrinsic radiosensitivity; Ionizing-radiation; Cervical-carcinoma; Human-lymphocytes; Immune-systemEx vivoDevelopmental BiologyMechanisms of Ageing and Development
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Pharmacological genome demethylation increases radiosensitivity of head and neck squamous carcinoma cells

2011

Aberrant inactivation of tumor suppressor genes by promoter hypermethylation has been recognized as a crucial step of tumor development and is related to aggressiveness and therapy resistance. To identify potential novel treatment strategies, we evaluated pharmacological genome demethylation for the increase of irradiation treatment effectiveness in head and neck squamous cell carcinoma (HNSCC) in this in vitro study. HNSCC cells were cultured with 2 different concentrations of 5-azacytidine (5-Aza) for 72 h, followed by a single fraction irradiation with 4 or 50 Gy, respectively. To show successful genome demethylation, the methylation status of the tumor suppressor gene hic1 (hypermethyla…

Transcriptional ActivationAntimetabolites AntineoplasticTumor suppressor geneBisulfite sequencingBiologyRadiation ToleranceCell Line TumorGeneticsmedicineHumansRadiosensitivityPromoter Regions GeneticDemethylationOncogeneSquamous Cell Carcinoma of Head and NeckGeneral MedicineDNA MethylationCell cyclemedicine.diseaseHead and neck squamous-cell carcinomaSquamous carcinomaGene Expression Regulation NeoplasticHead and Neck NeoplasmsAzacitidineCarcinoma Squamous CellCancer researchInternational Journal of Molecular Medicine
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Tumor Oxygenation Under Normobaric and Hyperbaric Hyperoxia

1997

Tumor hypoxia is an important factor limiting the efficiency of sparsely ionizing ra-diation and O2-dependent chemotherapy. Since the tumor pO2 is the result of a dynamic steady state between oxygen supply and O2 consumption of the tumor tissue, hypoxia could be reduced either by increasing the O2-supply or by reducing the O2 demand of the tumor cells. The O2 supply can be improved for instance by (i) increasing the arterial oxy-gen partial pressure, (ii) improving (and homogenizing) the tumor perfusion, or (iii) en-hancing the O2 release from blood into the tissue by right-shifting the HbO2 dissociation curve. Theoretically, it should also be possible to improve tumor oxygenation by a rela…

medicine.medical_specialtyChemotherapyTumor hypoxiabusiness.industryHyperbaric oxygenationmedicine.medical_treatmentOxygen–haemoglobin dissociation curveTumor OxygenationHyperbaric hyperoxiaInternal medicineTumor perfusionCardiologyMedicineRadiosensitivitybusiness
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