Browsing by Author "P.P.W. van Buul"

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Chromosomal damage induced in human lymphocytes by low doses of D-T neutrons
(1986) J. Pohl-Rüling; P. Fischer; D.C. Lloyd; A.A. Edwards; A.T. Natarajan; G. Obe; K.E. Buckton; N.O. Bianchi; P.P.W. van Buul; B.C. Das; F. Daschil; L. Fabry; M. Kučerová; A. Léonard; R.N. Mukherjee; U. Mukherjee; R. Nowotny; P. Palitti; Z. Polívková; T. Sharma; W. Schmidt
Unstable chromosome aberrations induced by in vitro irradiation with zero plus seven low doses of 14.8 MeV D-T neutrons in the range 3.55-244 mGy have been analysed in human peripheral blood lymphocytes. In order to obtain the required large numbers of scored cells for such low doses, fourteen laboratories participated in the experiment. The dose responses for dicentrics, excess acentrics and total aberrations, fitted well to the Y = αD model. The α coefficient of yield for dicentrics, 1.60 ± 0.07 × 10-2 Gy-1, compares well with the values obtained in previous studies with D-T neutrons at somewhat higher doses. Results from a previous collaborative study using 250 kVp X-rays over a comparable dose range indicated the possible existence of a threshold below 50 mGy. In the present study there is no clear evidence for neutrons for such a threshold. However, the data were insufficient to permit the rejection of a possible threshold below ∼ 10 mGy. © 1986.
Effect of low-dose acute X-irradiation on the frequencies of chromosomal aberrations in human peripheral lymphocytes in vitro
(1983) J. Pohl-Rüling; P. Fischer; O. Haas; G. Obe; A.T. Natarajan; P.P.W. van Buul; K.E. Buckton; N.O. Bianchi; M. Larramendy; M. Kučerová; Z. Poliková; A. Leonard; L. Fabry; F. Palitti; T. Sharma; W. Binder; R.N. Mukherjee; U. Mukherjee
In a coordinated research programme sponsored by the Internation Atomic Energy Agency, the frequencies of chromocomal aberrations induced in peripheral blood lymphocytes (in vitro) by 250 kV X-rays at low doses (0.4, 1, 2, 3, 5, 10 and 30 rad) were determined. Blood from 2 donors was used to conduct one master experiment at these dose levels. The culture time used was 48 h and all samples including the controls were processed according to a standard protocol. The coded slides were scored by investigators from 10 participating laboratories. The main results are the following: (1) the frequencies of all types of chromosome aberrations at 0.4 rad are significantly lower than the control values; (2) there is no increase in the frequencies of dicentrics up to 2 rad and in those of terminal deletions up to 5 rad; (3) the mean frequencies of all aberrations considered together are not significantly different from one another at 1,2 and 3 rad (P = 0.05); and (4) over the entire dose range the dose-effect relationship is clearly non-linear. A fit of these data to a linear quadratic model (E(D) = c + αD + βD2) showed that the observed total aberration frequencies at doses 1,2,3 and 5 rad are below the curve defined by the model. The deviations can be explained by an altered kinetics of aberration production at very low doses probably due to DNA repair mechanisms operating in these cells. © 1983.
Evaluation of radiation-induced chromosomal aberrations in human peripheral blood lymphocytes in vitro results of an IAEA-coordinated programme
(1982) M. Bianchi; N.O. Bianchi; J.G. Brewen; K.E. Buckton; L. Fabry; P. Fischer; P.C. Gooch; M. Kucerova; A. Léonard; R.N. Mukherjee; U. Mukherjee; S. Nakai; A.T. Natarajan; G. Obe; F. Palitti; J. Pohl-Rüling; H.G. Schwarzacher; D. Scott; T. Sharma; E. Takahashi; C. Tanzarella; P.P.W. van Buul
The results of an IAEA coordinated programme on radiation induced chromosomal aberrations in human peripheral blood lymphocytes in vitro are presented. In a master experiment, a whole blood sample from one donor was irradiated with 200 R of X-rays. Different fixation times from 46 to 82 h were used. The progression of cells into mitosis was monitored by BrdUrd incorporation. 14 investigators took part in the scoring of chromosomal aberrations. The main conclusions of this study are: (1) The mean frequencies of aberrations changed with fixation time. (2) The number of cells scored as aberrant by different laboratories was very similar, but there was variability in the number of aberrations scored per aberrant cell. (3) The differences in the frequencies of aberrations between laboratories were minimal when the scoring was restricted to the first major peak of mitotic activity and sufficient cells were scored. It is concluded that using controlled experimental conditions, human peripheral blood lymphocytes can effectively be used as a reliable biological dosimeter for absorbed radiation dose. © 1982.