A MWPC with a cathode coupled delay line read-out as radioactivity detector for DNA repair studies

A non selective method for the isolation of DNA repair-deficient mutants in mammalian cells is discussed. The method requires radioactive labelling of the short DNA sequences synthesized during repair of damaged regions. Mutants should be recognized by the absence of radioactive incorporation into thier DNA. A multiwire proportional chamber (MWPC) is proposed as a suitable radioactivity detector. The performance of a MWPC prototype with a cathode coupled delay line read-out is described and is shown to be adequate for this application. The main avaantages of a MWPC are reviewed with respect to other methods used for β− radioactivity counting of biological samples, such as liquid scintillators or autoradiography: the proposed detection method is non destructive for the cells, which are being kept alive for further biological studies; furthermore many cell clones can be screened within a reasonable time

ELECTRONIC AUTORADIOGRAPHY OF LIVING HUMAN-CELLS WITH A MWPC

Abstract The use of multiwire proportional chamber (MWPC) for mapping the incorporation of a radioactive precursor of DNA biosynthesis by aggregates of cells is discussed. The resolving power, sensitivity and linearity of the developed system are shown, together with preliminary "electronic autoradiograms" of 14C-labelled cells

DNA-repair deficient cells identification with a multiwire proportional chamber

Abstract Tritium labelled mammalian cells with defective repair of UV-induced damage have been identified by using a MWPC as a position sensitive radioactivity detector. The resolving power (≅1.5mm FWHM), sensitivity (≅101Bq/cm2), efficiency (≅10%) and uniformity (≅4%) of the detection system are shown and "electronic autoradiograms" of normal and mutant cultures are presented; cells, rescued after the radioactivity measurement, retain their cloning ability

Biomedical applications of digital autoradiography with a MWPC

A Multiwire Proportional Chamber (MWPC) was used as a ..beta../sup -/ radioactivity detector in biological and medical applications. Two different kinds of experiments were performed: the study of variations in the ability of cell clones to incorporate a radioactive precursor of DNA biosynthesis (/sup 3/H-thymidine) and the regional carbohydrate consumption in myocardial tissue by means of a deposit tracer of glucose metabolism (/sup 3/H-deoxyglucose)