| The effect on the Km for radiosensitization at 0 degree C of thiol depletion by diethylmaleate pretreatment: quantitative differences found using the radiation sensitizing agent misonidazole or oxygen. | |
| | |
MedLine Citation:
|
PMID: 6718689 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
|
Pretreatment of V79- WNRE cells with 150 microM diethylmaleate for 1 hr at 37 degrees C caused a decrease in intracellular glutathione levels to approximately 10-15% of control levels (0.5 vs 5.0 nmol/10(6) cells). The cells could be washed free of diethylmaleate and held at 0 degree C for several hours without toxicity and with no increase in glutathione concentration, although the glutathione concentration rapidly increased to normal levels at higher temperatures. Survival curves were determined as a function of oxygen or misonidazole concentration (the latter in the absence of oxygen). A new "thin-film" technique was used to avoid changes in oxygen concentration because of radiochemical or cellular oxygen consumption. Glutathione depletion itself caused a small but consistent radiosensitization of hypoxic cells (dose enhancement ratio of 1.2). However, glutathione depletion caused a profound change in the radiosensitizing efficiency of misonidazole, with a decrease in Km of about sevenfold from 0.6 to 0.09 mM. In contrast, only a 2.5-fold decrease was found in the Km for radiosensitization by oxygen with diethylmaleate pretreatment. These results suggest a fundamental problem with the conventional theory of radiosensitivity whereby one considers a first-order competition for reaction with target radicals between radical-fixing versus radical-repairing species. It also suggests difficulties in the interpretation of glutathione as the only endogenous protective species. |
| | |
Authors:
|
C J Koch; C C Stobbe; E A Bump |
Related Documents
:
|
1648459 - Intracellular production of reactive oxygen species in human neutrophils following acti... 19153729 - A flow injection analysis system with encapsulated high-density saccharomyces cerevisia... 6094369 - In vitro determination of phagocyte activity by luminol- and lucigenin-amplified chemil... 7378899 - Quantitative correlation between the reduction of nitroblue tetrazolium and the oxygen ... 16709639 - Amp-activated protein kinase and the regulation of ca2+ signalling in o2-sensing cells. 20163859 - 2-(4-chlorophenyl)benzo-1,4-quinone induced ros-signaling inhibits proliferation in hum... 8314599 - Electro-immortalization of b lymphocytes isolated from stomach carcinoma biopsy material. 2164679 - Autocrine transformation by chimeric signal peptide-basic fibroblast growth factor: rev... 20507709 - Effect of thermal degradation of sff-based plga scaffolds fabricated using a multi-head... |
Publication Detail:
|
Type: Journal Article; Research Support, Non-U.S. Gov't |
Journal Detail:
|
Title: Radiation research Volume: 98 ISSN: 0033-7587 ISO Abbreviation: Radiat. Res. Publication Date: 1984 Apr |
Date Detail:
|
Created Date: 1984-06-20 Completed Date: 1984-06-20 Revised Date: 2006-11-15 |
Medline Journal Info:
|
Nlm Unique ID: 0401245 Medline TA: Radiat Res Country: UNITED STATES |
Other Details:
|
Languages: eng Pagination: 141-53 Citation Subset: IM; S |
Export Citation:
|
APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
|
Animals Cell Survival / drug effects, radiation effects* Cells, Cultured / drug effects Cesium Radioisotopes Cricetinae Cricetulus Dose-Response Relationship, Drug Dose-Response Relationship, Radiation Gamma Rays Glutathione / physiology* Maleates / pharmacology Misonidazole / pharmacology* Nitroimidazoles / pharmacology* Oxygen / pharmacology* Radiation-Sensitizing Agents / pharmacology* |
| Chemical | |
Reg. No./Substance:
|
0/Cesium Radioisotopes; 0/Maleates; 0/Nitroimidazoles; 0/Radiation-Sensitizing Agents; 13551-87-6/Misonidazole; 141-05-9/diethyl maleate; 70-18-8/Glutathione; 7782-44-7/Oxygen |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
Previous Document: Accelerated heavy particles and the lens. I. Cataractogenic potential.
Next Document: Gamma-irradiation effects on phosphatidylcholine multilayer liposomes: calorimetric, NMR, and spectr...