Biomedical subjects
Publications and source records attributed to I Pridal.
Present work reports on results of manual brachytherapy in lung cancer using intrabronchial catheter and 226-radium source. Expected dosage was 18 Gy at 1 cm from the source. This therapy was combined with external radiotherapy by 60-cobalt till the dosage about 65 Gy. 19 men were treated, the mean survival was 14.3 months. Advantages and disadvantages of the method are discussed.
The authors used as palliative analgetic treatment half-body irradiation in 13 patients with dissemination of a malignant tumour into bones. In six patients both halves of the body were irradiated. A long-term analgetic effect was observed in five patients (in one female patient more than 400 days, four patients 100-150 days), a short-term effect up to 100 days was recorded in six patients. The pain was not influenced in two patients. Mitigation of pain increased the patients' performance: according to the WHO scale in one case by 3 grades, in three patients by 2 grades, in six patients by 1 grade. The performance of three patients was not affected by irradiation. Side-effects of treatment were controlled by means of supporting treatment. They did not threaten life in any of the patients. The authors consider half-body irradiation an effective and useful analgetic treatment of multiple metastases into the bones.
A simple mathematical model of DSB distributions in DNA from irradiated interphase eukaryotic cells is considered and an approximate description of resulting DNA sedimentation profiles is derived. The model takes into account the differences found between the radiosensitivities of heterochromatin and euchromatin and is based, contrary to the usual approach, on a non-homogeneous distribution of DSB in eukaryotic DNA. Comparison with some experimental DNA sedimentation profiles prefers the proposed model to the common one. At the same time a greater radiosensitivity difference (at least in yeast cells for the present) has been established in anoxic conditions compared to aerobic ones.
A model of repair kinetics of DSB based on a step-by-step removal of individual double-strand breaks inside an autonomous repair unit is proposed and compared with the alternative model commonly used in modelling repair kinetics, which is based on an assumption of stochastic removal of cellular lesions. The former model seems to be preferred by the recently published experimental data displaying the time decrease of average DSB number per cell in irradiated Saccharomyces cerevisiae (strain 211 B) held in non-growth conditions.