Radioprotective effects of amifostine (WR-2721) or cystamine on radiation damage and its repair in rats whole body exposed to fission neutrons.

Sulphur containing radioprotective drugs amifostine (gammaphos, WR-2721) or cystamine (disulfide of meracaptoethylamine) of Czechoslovak production were examined in whole body fission neutrons irradiated rats in the thermal column of reactor VVR-S. Using the split-dose technic the first sublethal neutron dose in the range 1-2 Gy was followed by second lethal exposures in the two time intervals (3 or 6 days) using whole body fission neutrons irradiations (3 days interval) or whole body gamma-irradiations (6 days interval) for LD50/30 evaluation within next 30 days survival observation. In other experiments the mean survival time (MST) in days was estimated in different rats group, when animals were whole body fission neutrons irradiated twice with 3-days interval using the total lethal doses of 4 or 5 Gy.

[Basic principles of physics in optical imaging of the human eye].

Creation of a real picture of the observed object on the retina by optical system of the eye is the primary physical condition of the visual perception. Absorption of the light energy initiates the sequence of further physicochemical, biochemical and psychophysiological events partially taking place already in the retina but mostly in the higher cerebral and spinal centres. So the visual perception and its final evaluation is the result of a complicated complex of processes where the optical imaging itself plays the role of the starting factor.

[Biophysical principals in radiotherapy of malignant tumors].

The successfulness of tumour radiotherapy depends before all on achieving the maximal effect of radiation on the tumour with contemporary minimalization of the injury of normal tissues in its vicinity. Such selectivity of radiation action may be realized by utilization of physical (kind and energy of radiation, irradiation conditions) as well as biological (modification of radiation effects) factors. The aim of this publication is to give a survey of fundamental biophysical and radiobiological principles conditioning the differential action of ionizing radiation on tumorous and normal cell populations from the standpoint of the relevancy of experimental radiobiology (radiation effect on the proliferative capacity of the tumorous and normal tissue) to radiotherapy.

[Screening for venous thrombosis and pulmonary embolisms in patients with stroke using an adaptive classifier].

The use of adaptive linear neuron is referred to in recognizing veinous thromboses and lung embolism in a total of 88 acute palsies. As the input signs, the accessible clinical and laboratory data were used. Both training and adaptation of neuron have been performed in a part of total [35 patients], and 53 patients were submitted to the classification of patients with unknown distribution.

Use of the adaptive classifier for determination of LD50 in the acute radiation disease.

In experiments on female Wistar rats a new method for the determination of LD50 is demonstrated and compared with the classical probit method using the same experimental animals. The method is applicable for the computation of LD50 and analogical quantities in man, too. The method is based on the application of an adaptive logical circuit (ADALINE) trained for the dichotomous prognostic classification of irradiated individuals quod vitam according to a set of clinical and laboratory indicators registered on the third day after irradiation.