The radiation modifying properties of carnosine

The influence of carnosine (beta-alanyl-l-histidine) on the survival rate of albino mice subjected to whole-body X-irradiation has been investigated. Carnosine (50-200 mg/kg/day) administered per os during a period of 20 days before irradiation (5.0 Gy) increased the survival rate by 45-65%, whereas the administration of carnosine within 30 days after irradiation (5.5 Gy) produced an insignificant protective effect and caused inhibition of the postirradiation histamine accumulation in the spleen.     

The modifying effect of an electric current on the course of radiation injuries in animals

A simultaneous action of the modified electric current and ionizing radiation (5.5-25 Gy) was shown to decrease the death rate, to increase the life-span of rats, and to induce the intestinal syndrome at higher doses than the action of each factor delivered separately. There was a correlation between the modifying effect and the faster restoration of cellularity of bone marrow and peripheral blood, and the number of nucleate enterocytes of the small intestine mucosa.     

The modifying effect of the frequency of pulses of ionizing radiation on its efficiency in biological experiments

In biological experiments the ionizing radiation is usually defined by the type, energy and total absorbed dose, as well as by the dose rate. If radiation generated by a physical particle accelerator is employed, we consider it necessary to supplement these data with the value for frequency of pulses of the ionizing radiation jet. As follows from our experiments, this parameter expressively affects the relative biological effect of ionizing radiation.     

The modifying effect of novocaine on the clinical manifestations of the intestinal form of radiation sickness]

On rats and dogs exposed to absolute lethal doses of X-irradiation (rats--10, 12 Gy; dogs--15 Gy sublethally) it has been shown that novocaini injection to animals immediately after radiation exposure reduces the primary radiation reaction and at the same time shifts the changes in morphofunctional state of peripheric blood on 24 hours, reduces the symptoms of acute radiation sickness, increases the average life length of the animals on 1,5 days. A conclusion concerning the expressed therapeutic influence of intraperitoneal novocaini injection immediately after radiation has been drawn.     

The effect of cryopreservation and transplantation factors on the morphofunctional state of the thyroid in dogs

Influence of transplantation of non-specific factors (denervation, delymphatization, surgical trauma, ischemia, changes in blood supply conditions) as well as the effect of cryopreservation (-196 degrees C) on morphological structure and ability for secretion of thyroid hormones and response to TS stimulation were studied using the model of extracorporal biological perfusion in isolated thyroid of dogs. The results of biochemical and morphological investigations of thyroid in different conditions of perfusion showed, that it had preserved its main functional and morphological characteristics under the action of transplantation of nonspecific factors and extremely low temperatures.     

The effect of modifying factors on the absorption of radioactive beryllium from the gastrointestinal system of rats

In experiments with rats a study was made of the influence of pregnancy and lactation as well as of trivalent and bivalent iron on the resorption of 7BeCl2 from the digestive tract and distribution thereof among organs and tissues.     

Analysis of the modifying effect of liver injury on the course and outcome of acute radiation sickness

In studying the aggravating effect of liver injury on the development of radiation sickness in irradiated rats it was found that the death rate increased within the range of minimal and median lethal doses and was not associated with the aggravation of both the haematologic and the hemorrhagic syndromes; it was not related to infectious complications as well. The data are presented on auto-intoxication as a factor aggravating the outcome of the combined radiation injury.     

Glucan effect on the survival of mice after radiation exposure

The effect of glucan (beta-1,3-polyglucose) was investigated on the radiation-induced damage to the system of non-specific immunity in mice. A positive influence of glucan administered before exposure to a dose of 200 R was observed on the following parameters of postradiation regeneration: while blood cell count, due mainly to increased granulocyte count, increased per cent of peroxidase-positive cells in bone marrow, increased mass and cellularity of the spleen, in relation to the group of the animals not receiving the preparation. Administration of glucan 5 days before exposure to 650 R of X-rays prolonged the mean survival time. Administration of the preparation after exposure to radiation had no significant effect on the survival time of mice.     

The effect of exposure to enhanced UV-B radiation on the penetration of monochromatic and polychromatic UV-B radiation in leaves of Brassica napus

Using quartz optical fibres, penetration of both monochromatic (310 nm) and polychromatic UV-B (280–320 nm) radiation in leaves of Brassica napus L. (cv. Ceres) was measured. Plants were grown under either visible light (750 μmol m⁻² s⁻¹ photosynthetically active radiation) or with the addition of 8. 9 KJ m⁻² day⁻¹ biologically effective UV-B (UV-B_BE) radiation. Results showed that of the 310 nm radiation that penetreated the leaf, 90% was within the intial one third of the leaf with high attenuation in the leaf epidermis, especially in UV-treated plants. Polychromatic UV-B radiation, relative to incident radiation, showed a relatively uniform spectral distribution within the leaf, except for collimated radiation. Over 30% of the UV-screening pigments in the leaf, including flavonoids, were found in the adaxial epidermal layer, making this layer less transparent to UV-B radiation than the abaxial epidermis, which contained less than 12% of the UV-screening pigments. UV-screening pigments increased by 20% in UV-treated leaves relative to control leaves. Densely arranged epicuticular wax on the adaxial leaf surface of UV-treated plants may have further decreased penetration of UV-B radiation by reflectance. An increased leaf thickness, and decreases in leaf area and leaf dry weight were also found for UV-treated plants.     

The participation of thyroid hormones in modifying the mutagenic effect of microwaves

The mutagenic effect of microwaves (2,450 or 2,750 MHz, 500 microW/cm2, 30 days, 7 h a day) increases with both low and high thyroid hormone content in rats. This indicates that normal functioning of the thyroid gland is an important condition for the stabilization of chromosome integrity under the effect of nonionizing radiation of microwaves.     

The effect of chronic exposure to cadmium and gamma radiation at low doses on the genetic structures in mice

The DNA-protein cross-links (DPC) in mouse thymocytes and spleen lymphocytes, the number of abnormal sperm heads (ASH) and the number of micronuclei (MN) in normochromatic erythrocytes (NCE) of peripheral blood were studied in mice exposed to long-term low-intensity gamma radiation (0.072 cGy/days) and/or cadmium with drinking water (0.01 mg Cd2+/l) for 20, 40 and 80 days. The dependence of DPC level on the total dose (exposure time) of gamma radiation and/or cadmium is nonlinear. The maximal level of DPC in cells of lymphoid organs upon exposure to gamma radiation or cadmium was recorded on the 40-th day, and under combined exposure on the 20-th day of the experiment. The long-term exposure to cadmium or gamma radiation causes an increase in the ASH frequency. The increase in frequencies of MN in NCE and reciprocal translocations in spermatocytes was not found.