Biomedical subjects

H Dertinger

Publications and source records attributed to H Dertinger.

34 records · Page 2Linked to original sources

PubMed1975

The action of ionizing radiation on DNA in the presence of quinacrine. I. UV absorption and fluorescence measurements.

It is shown by UV absorption and absolute fluorescence spectroscopy of solutions containing both DNA and quinacrine that the components experience mutual radio-protection due to scavenging of water radicals. From measurements at different ionic strengths it is inferred that quinacrine bound to DNA is more efficiently protected than the free compound. Furthermore, release of bound quinacrine from DNA is observed at higher doses.

Animals↗

PubMed1975

The action of ionizing radiation on DNA in the presence of quinacrine. II. DNA strand breakage.

Strand breakage of DNA irradiated in solution and in the dry state in the presence of quinacrine was investigated by sedimentation analysis. Determination of single strand breaks in solution combined with binding studies permits to conclude that bound quinacrine protects DNA more effectively than the free compound. In the dry state quinacrine is without detectable effect on both single and double strand break formation, neither under aerobic nor anaerobic conditions.

Aerobiosis↗

PubMed1975

Energy requirements for damaging DNA molecules. III. The mechanisms of inactivation of bacteriophage chiX 174 DNA by vacuum ultra-violet radiation.

Strand break formation and biological inactivation of infectious DNA of bacteriophage phi chi 174 exposed to vacuum-ultra-violet radiation of 4-9 to 21-2 eV quantum energy is investigated. At 21-2 eV as many as 84 per cent of the DNA molecules are inactivated by breaks whereas breaks do not contribute to inactivation at 4-9 eV. The quantum yield of break formation increases from 1-7 X 10(-5) (4-9 EV) to 0-55 (21-2 eV) and shows a dependence on energy similar to that of electron emission (due to ionization) above 8 eV. The mechanisms leading to break formation and inactivation are discussed taking the absorption spectrum of DNA in the vacuum-ultra-violet region into consideration.

Coliphages↗

PubMed1975

A comparative study of post-irradiation growth kinetics of spheroids and monolayers.

Post-irradiation growth kinetics of gamma-irradiated spheroid and monolayer cells in exponential growth phase was investigated by means of dose-response curves based on cell counts after specified time intervals following irradiation. A mathematical model of cell-growth after irradiation was fitted to these curves. The model parameters (related to division delay and growth of non-surviving cellsy obtained from this analysis consistently indicate increasing resistance to sub-lethal damage of cells cultured as multicellular spheroids under conditions of increasing three-dimensional contact. In contrast, no indication of an increased radiation-resistance was found with cells cultured on a substratum under a variety of conditions.

Cell Division↗

PubMed1973