Correlation between the complex of body reactions to exposure to acute hypoxia and individual radiosensitivity in irradiation at a dose of 200 Gr

A study was made of a correlation between the response of basal metabolism to acute hypoxia and the life span of rats after irradiation resulting in the development of a cerebral form of radiation sickness. The more radiosensitive animals consumed a larger amount of oxygen, exhaled a lesser amount of carbon dioxide, and showed an increased normal expiratory exchange per minute. After the effect of acute hypoxia all the indices under study exhibited an opposite picture.     

Effect of ionizing radiation on the functional state of the vascular-thrombocytic component of the hemostasis system

The influence of ionizing radiation (gamma-rays 60Co) on aggregation activity of the vascular wall and functional (aggregation) platelet activity was studied in the course of the development of acute radiation sickness. The decrease in the aggregation properties of the vascular wall and high functional activity of platelets were inversely proportional, correlating with the periods of acute radiation sickness development and depending on the radiation dose. It is suggested that the changes detected may play a role in the pathogenesis of the development of the postirradiation thrombohemorrhagic syndrome.     

Changes in labrocytes during acute radiation sickness (morphometric study)

Changes in the morphometric parameters of rat mast cells during acute radiation sickness have been studied. The most significant deviation of the quantitative indices of mast cells from the control values were noted at the height of the bone-marrow, at the terminal stage of the intestinal, and during the first few hours of the cerebral forms of acute radiation sickness.     

A possible approach to large-scale laboratory testing for acute radiation sickness after a nuclear detonation

After the detonation of an improvised nuclear device, several key actions will be necessary to save the greatest number of lives possible. Among these tasks, the identification of patients with impending acute radiation sickness is a critical problem that so far has lacked a clear solution in national planning. We present one possible solution: the formation of a public-private partnership to augment the capacity to identify those at risk for acute radiation sickness.     

Combined effect of normobaric hyperoxia and vibration on the radiosensitivity of animals

In experiments with hybrid mice (CBA X C57B1)F1 and F2(CBWA), a study was made of the combined effect of normobaric hyperoxia and vibration on sensitivity of the organism to gamma-radiation. A single and protracted (for 5 days, daily) vibration before irradiation aggravated acute radiation sickness. A modifying effect of hyperoxia on the development of the intestinal form of radiation sickness was the same as that observed under the effect of vibration. In the experiments with tetrahybrids, the combined effect of the two factors aggravated drastically the intestinal syndrome of acute radiation sickness (DMF = 1.24).     

Parametric analysis of survival data for doubly irradiated animals

On the basis of their previously reported model of acute radiation sickness development the authors made a parametric analysis of the survival rate of mice after double exposure to ionizing radiation.     

Morphological types of radiation-induced hematopoietic tissue cell death,its biological essence and significance at various stages of developing acute radiation injury

The results of morphologic investigation of radiation-induced cell death types in human and animal (dogs) hematopoietic tissue within an acute radiation injury are presented. It has been shown that early and late necrobiosis of myelokaryocytes occurs via apoptosis. An attempt to designate the pathogenic role of apoptosis in hematologic syndrome of acute radiation sickness was performed.     

EPR study of the blood of animals during an acute radiation lesion

The intensity of the ESR signal of methemoglobin, Fe3+-transferrin, and Cu2+-ceruloplasmin in blood and spleen of mice exposed to 6 Gy radiation was shown to undergo considerable changes at early times of acute radiation sickness.     

15 years after the accident at the Chernobyl Nuclear Power Plant

Health effects as a result of the accident at the Chernobyl nuclear power plant occurred in 1986 are considered in the paper. Wrong prognosis of the health effects with respect to mortality and morbidity among the population exposed to low radiation doses is shown. Proven increase in thyroid cancer cases among people who were children aged from 0 to 18 at the time of the accident is shown. Linear relationship between thyroid cancer cases and dose to thyroid ranged from 0.2 to 4.0 Gy is considered. An additional absolute risk of thyroid cancer in children varies in the range 1.9-2.6 cases per 10(4) person-year Gy. During the fifteen years following the accident no cases of acute and chronic radiation sickness have been revealed because the population living in contaminated areas received low radiation doses. Also, exposures to low radiation doses did not result in excess of malignant tumors among population. In some cases the outcomes of acute radiation sickness were as follows: radiation damages to the skin, cancer cataracts, development of oncopathology.     

Multivariate statistical analysis of tissue basophils in acute radiation sickness

By means of mark scale estimation method, discriminant and factor analyses, changes in integral indices on the state of mast cells in the rat mesentery have been investigated in dynamics of medullary, intestinal and cerebral forms of an acute radiation sickness. The integral indices are calculated basing on the morphometric parameters of the cells, that are obtained after the histological preparations are treated in a special automatic system for analysing images. At the medullary form of the acute radiation sickness, the greatest structural rearrangements of the mast cells take place during the first hours after the radiation, as well as during the climax of the disease, at the intestinal form, the analogous changes are revealed 1-3 days after the effect, and at the cerebral form--3 h after the radiation. The integral indices, calculated by means of the three methods, are well correlated with each other.     

Morphofunctional characteristics of the cells of the APUD system of the adrenal glands and the duodenum in the cerebral form of acute radiation sickness

Changes of a phase nature develop in the APVD system cells of rats, dogs, and monkeys exposed to electron radiation of doses inducing a cerebral form of radiation sickness. These changes in the morphofunctional status of APVD system cells may be considered as a syndrome displaying acute radiation apudopathies.     

Dosimetric criterion for the intestinal form of acute radiation lesions in man. The loss of the barrier properties of the small intestine--an index of the severity of the lesion

Dynamics of cell regeneration in the small intestine epithelium of man has been investigated in normal conditions and after acute exposure to ionizing radiation. It is suggested that the severity and outcome of the intestinal form of acute radiation sickness are determined by the time interval within which the number of functional cells of the epithelium villi remains below some threshold level that provides the retention of barrier properties of the small intestine.     

Mechanism of circulatory disorders in animals irradiated at high doses

Some data are reported on pathoanatomical changes, a status of the microcirculatory channel and the coagulogram of animals affected by high doses of ionizing radiation. The signs of disseminated intravascular blood coagulation have been revealed. The authors discuss the relationship between clinical manifestations with coagulopathy development and circulatory disturbances during intestinal and cerebral forms of acute radiation sickness.     

The status of the endocrine function of the thymus in acute radiation sickness resulting from the accident at the Chernobyl Nuclear Power Station

Data are presented on the role of inhibition of endocrine function of the thymus in the pathogenesis of acute radiation sickness resulted from the direct and indirect (via the increased glucocorticoid production) effects of ionizing radiation. The complex treatment, including nonspecific active immunotherapy, permitted to normalize the thymic hormone level and certain parameters of the immune system.     

Comparison of the possibilities of micronuclear and chromosomal aberration tests for evaluation of the effects of radiation of different intensities

The comparative evaluation of sensitivity and specificity of the micronucleus and chromosome aberration tests for human lymphocytes at the delayed terms after acute exposure to high-dose as well as during constant exposure to low-dose gamma-radiation has been done. Accordance between these tests registered only in the cases of acute radiation sickness of second and third degrees of severity (irradiation doses above 200 cGy). Unspecificity of micronucleus test for estimation of the radiation load under constant low-intensity irradiation was found.     

The distribution of radiation-induced breaks in the chromosomes of irradiated subjects

Distribution of radiation-induced breakpoints in chromosomes and its bands in persons recovered from acute radiation sickness and personnel from Chernobyl NPP were investigated using G-banding staining. The frequency of damaged bands and breakpoints in groups exposed to radiation was significantly higher as compared with the control group. It was shown that in exposed to radiation persons damage depends on its length. Most frequently damaged bands in the observed groups were determined. The G-negative bands and telomeres of chromosomes were more sensitive to radiation.     

Efficiency of polysaccharide translam for early treatment of acute radiation illness

Antiradiation therapeutic efficiency of translam (1-->3; 1-->6-beta-D-glucan) produced by enzymatic synthesis out of laminarin, polysaccharide of Laminaria cychorioides, has been studied in four animal species (mice, guinea-pigs, dogs, monkeys). A stable curative effect has been observed following its administration within first 24 h after radiation exposure at doses that cause acute radiation sickness (about LD90). The preparation is nontoxic and has a broad therapeutic range which permits its practical application.     

Changes in the concentration of serum fibronectin in irradiated animals

A study of the level of fibronectin in blood serum of Wistar rats at different times after gamma-irradiation (7.5 Gy) has demonstrated a considerable increase in its concentration after 3 days. This increase is a function of radiation dose absorbed (within the range from 1 to 10 Gy). The most pronounced changes are observed with serious and extremely serious forms of acute radiation sickness. The administration of cycloheximide 48 h after irradiation removes completely the increase in the level of blood serum fibronectin.     

Treatment of infectious complications of experimental acute radiation injury with combined antibiotic sulacillin

An anti-infectious effect of sulacillin (ampicillin/sulbactam) is higher than that of ampicillin in treatment of irradiated mice infected with a beta-lactamaseproducing strain of Kl. pneumoniae. Involving of sulacillin as a principal antibiotic into the therapeutic scheme for acute radiation sickness results in 67% dogs survival at LD90/45.