Different radiosensitivity of chinese hamster fibroblasts for chromatid breaks in G2/prophase. Dependence on LET

Mindek, G.; Riehle, I.; Cabeza, Laura; Fritz-Niggli, H

doi:10.1038/bjc.1975.330

Cited by 2 publications

(1 citation statement)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The induction of somatic mutations are studied in mammalian cells (Mindek et al, 1975) as well as in Drosophila (Schweizer et al, 1977) (Figs. 11, 12).…”

Section: Induction Of Mutationsmentioning

confidence: 99%

Radiobiological evaluation of the suitability of negative pions in tumor therapy; facts and theories

Fritz-Niggli

1979

Radiat Environ Biophys

View full text Add to dashboard Cite

Summary.A successful cancer radiotherapy consists mainly in sparing normal tissues and killing malignant cells. Negative pions seem to have several and unique gain factors, as Fowler and Perkins 1961 proposed. With the biomedical pion channel of the 590 MeV proton-accelerator of the Swiss Institute for Nuclear Research (SIN) we had since several years the opportunity to test some theoretical conceptions in comparison to several preliminary experiments performed with pions of low dose rate (Berkeley, CERN, Nimrod). The dosimetric measurements showed for the momentum of 180 MeV/c and a ratio e-/zr of 0.1 an excellent depth curve with p. ex: a peak/plateau ratio of 2.5. Besides this important gain factor for radiotherapy, negative pions have the unique particularity to act on the tissues in the same treatment with two different types of radiations, in the peak (treatment volume) with high LET radiation (presumably high RBE) and low LET radiation in the plateau. Following systems have been used: Inactivation of single mammalian cells, induction of chromatid aberrations in Chinese hamster cells; small intestine of mouse (early and late effects); early and late effects in mouse foot; induction of anomalies in mouse embryos; induction of cerebral microvascular damages in neonatal rats; proliferation of Ehrlichascites carcinoma cells; induction of different types of mutation in different stages of male germ cells and somatic cells (Drosophila). The RBE-values in the peak region vary between 0.7-3.3, and are different even in the same system with the same end point but at different cell stages and conditions. For the plateau region the RBE-values lie mostly under 1 (compared with 140 kVphotons) and can be identical with 29 MeV-photons. The clinically important peak/plateau relation lies in every experiment over 1 and reaches even the value of 4.2. The unexpected RBE-values in peak under 1 lead to a new conception of RBE, the two system theory. In intrinsic radiosensitive euoxic systems (healthy tissue) the RBE of peak (star) pions can be under 1, in intrinsic radioresistant hypoxic systems (tumor cells) in contrary over 1. The two systems can also have different vulnerability of repair system.

show abstract

“…The induction of somatic mutations are studied in mammalian cells (Mindek et al, 1975) as well as in Drosophila (Schweizer et al, 1977) (Figs. 11, 12).…”

Section: Induction Of Mutationsmentioning

confidence: 99%

Radiobiological evaluation of the suitability of negative pions in tumor therapy; facts and theories

Fritz-Niggli

1979

Radiat Environ Biophys

View full text Add to dashboard Cite

show abstract

Chromatid breaks induced in Chinese hamster cells by low doses (12?100 rad) of? ?-mesons

Mindek

Blattmann

Cordt

et al. 1979

Radiat Environ Biophys

View full text Add to dashboard Cite

Monolayer cultures of the fibroblast-like Chinese hamster cell-line 19/1 were irradiated in the G2-phase of the cell cycle by pi--mesons (6 rad/min peak-pion dose rate). Frequencies of induced single- and isochromatid breaks, acentric fragments and interchanges were compared with data obtained from 140 kV X-rays. The RBE-values were for the pion dose peak between 0.8--1.2 and for the pion dose plateau 0.5--0.9. Whereas for single chromatid breaks there was no significant difference between X-rays and peak pions for identical physical doses, the isochromatid breaks alone showed a significantly higher frequency for 100 rad peak pions.

show abstract

Different radiosensitivity of chinese hamster fibroblasts for chromatid breaks in G2/prophase. Dependence on LET

Abstract: These observations lead to the assumption that 2 different mechanisms are responsible for the atheromatosis.

Cited by 2 publications

References 0 publications

Radiobiological evaluation of the suitability of negative pions in tumor therapy; facts and theories

Radiobiological evaluation of the suitability of negative pions in tumor therapy; facts and theories

Chromatid breaks induced in Chinese hamster cells by low doses (12?100 rad) of? ?-mesons

Contact Info

Product

Resources

About