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Your search keyword '"Baumstark-Khan, C."' showing total 3 results
Start Over Author "Baumstark-Khan, C." Journal international journal of radiation biology
3 results on '"Baumstark-Khan, C."'

1. X-ray-induced DNA double-strand breaks as lethal lesions in diploid human fibroblasts compared to Chinese hamster ovary cells

Author

Baumstark-Khan C

Subjects
Programmed cell death, Cell Survival, Hamster, CHO Cells, Biology, Ionizing radiation, Cell Line, chemistry.chemical_compound, Cricetinae, medicine, Animals, Humans, Radiology, Nuclear Medicine and imaging, Fibroblast, Radiological and Ultrasound Technology, Chinese hamster ovary cell, X-Rays, Dose-Response Relationship, Radiation, DNA, Fibroblasts, Molecular biology, medicine.anatomical_structure, chemistry, Cell culture, Ploidy, DNA Damage
Abstract

Calibration of the non-denaturing (pH 9·6) filter elution technique by 125I decays has been used to examine the relationship between X-ray-induced DNA double-strand breaks (dsb) and cellular survival of CHO cells and human fibroblasts. DNA dsb induction varies markedly between the two cell lines, reflecting the different survival levels. The relationships between lethal lesions (− ln S) and DNA dsb are also significantly different for CHO cells and human fibroblasts, suggesting either different probabilities of dsb conversion into lethal lesions or different repair capacities.

Published
1993

2. Effect of aphidicolin on DNA synthesis, PLD-recovery and DNA repair of human diploid fibroblasts

Author

Baumstark-Khan C

Subjects
Aphidicolin, Adult, animal structures, DNA Repair, DNA polymerase, DNA repair, Cell Survival, viruses, chemistry.chemical_compound, medicine, Humans, Radiology, Nuclear Medicine and imaging, Fibroblast, chemistry.chemical_classification, Radiological and Ultrasound Technology, biology, DNA synthesis, urogenital system, organic chemicals, DNA, biochemical phenomena, metabolism, and nutrition, Fibroblasts, Molecular biology, medicine.anatomical_structure, Enzyme, chemistry, Cell culture, biology.protein, Female, DNA Damage
Abstract

The effect of aphidicolin, a specific inhibitor of DNA polymerases alpha and delta, was studied on DNA synthesis, PLD-recovery and DNA double-strand break rejoining in X-irradiated human fibroblasts. In unirradiated, exponentially growing cells, aphidicolin (0.5-5 micrograms ml) inhibited DNA synthesis almost completely. This effect depended not only on aphidicolin concentration but also on the duration of pre-incubation. The action of aphidicolin was found to be reversible. When aphidicolin had been removed, colony forming ability was not affected in aphidicolin pretreated cells. Aphidicolin pretreated and irradiated cells showed a reduction in PLD-recovery, dependent on aphidicolin concentration and duration of pretreatment. The initial number of DNA double-strand breaks (calibrated by 125I decay) was not affected by aphidicolin. However, after incubation for 90 min in the presence of aphidicolin there was a large reduction in double-strand break rejoining. With long incubation periods in aphidicolin rejoining was almost completely inhibited.

Published
1992

3. Activation of the nuclear factor κB pathway by heavy ion beams of different linear energy transfer.

Author

Hellweg CE, Baumstark-Khan C, Schmitz C, Lau P, Meier MM, Testard I, Berger T, and Reitz G

Subjects
Acceleration, Cell Survival radiation effects, Dose-Response Relationship, Radiation, Green Fluorescent Proteins genetics, HEK293 Cells, Humans, Relative Biological Effectiveness, Space Flight, X-Rays adverse effects, Heavy Ions adverse effects, Linear Energy Transfer, NF-kappa B metabolism, Signal Transduction radiation effects
Abstract

Purpose: Risk assessment of radiation exposure during long-term space missions requires the knowledge of the relative biological effectiveness (RBE) of space radiation components. Few data on gene transcription activation by different heavy ions are available, suggesting a dependence on linear energy transfer. The transcription factor Nuclear Factor κB (NF-κB) can be involved in cancerogenesis. Therefore, NF-κB activation by accelerated heavy ions of different linear energy transfer (LET) was correlated to survival., Materials and Methods: NF-κB-dependent gene induction after exposure to heavy ions was detected in stably transfected human embryonic kidney 293 cells (HEK-pNF-κB-d2EGFP/Neo cells carrying a neomycin resistance), using the destabilized Enhanced Green Fluorescent Protein (d2EGFP) as reporter., Results: Argon (LET 272 keV/μm) and neon ions (LET 91 keV/μm) had the highest potential to activate NF-κB, resulting in a RBE of 8.9 in comparison to 150 kV X-rays. The RBE for survival also reached its maximum in this LET range, with a maximal value of 2., Conclusions: NF-κB might be involved in modulating survival responses of cells hit by heavy ions in the LET range of 91-272 keV/μm and could therefore become a factor to be considered for risk assessment of radiation exposure during space travel.

Published
2011
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