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 possibility to predict the severity of individual damage following the exposure to supralethal radiation dosage. Prediction of working capacity of irradiated rats and dogs by response to pre-exposure physical load

The experiments on rats and dogs exposed to radiation doses which cause intestinal and cerebral forms of radiation sickness have shown that, within the first 24 hours post-exposure, efficiency impairment can be predicted by changes in some indices of the cardiovascular and endocrine systems after physical load used as a non-radiation testing agent. The goodness of fit of experimental data to the expected result is up to 50-70%, still rising if a number of indices for different sections of the neuroendocrine system are used at a time.     

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.     

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.     

A possibility to predict the severity of individual damage following the exposure to supralethal radiation dosage. Prediction of working capacity of irradiated rats and dogs by response to pre-exposure hypobaric load

In experiments on rats and dogs exposed to radiation doses which cause intestinal and cerebral forms of radiation sickness, hypobaric hypoxia used as an unconventional test of animals' reactivity has enabled the relationship between reactivity and radiosensitivity to be established. Higher post-radiation efficiency is observed in animals with less pronounced changes during a barotest. The goodness of fit of experimental data to the expected result is up to 70%, rising if a set parameters for one index or the sum total of indices are used.     

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.     

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.     

Mechanisms of the protective action of sulfur-containing radioprotectors on the intestinal epithelium

In studying the influence of cystamine and gammaphos on the recovery of mouse jejunum epithelium after irradiation with doses inducing intestinal form of acute radiation sickness, it was shown that the radioprotective agents did not influence D0 value for intestinal epithelium stem cells, but in crypts the number of DNA-synthesizing enterocytes that entered mitosis increased after the preventive administration of the radioprotectors. All this caused the number of cells per villus to increase and intestinal mucosa to recover more readily.     

A possibility to predict the severity of individual damage following the exposure to supralethal radiation dosage. Prediction of the clinical manifestation of radiation injury in laboratory animals by response to pre-exposure hypobaric hypoxia

The experiments on rats, dogs and monkeys exposed to radiation doses which cause intestinal and cerebral forms of radiation sickness have shown that the severity of a clinical state can be predicted by cardiovascular and endocrine changes when a pre-exposure test with moderate hypobaric hypoxia is performed. The goodness of fit of experimental data to the exposed result is up to 60-80%, still rising if a set of indices of the neuroendocrine status is used.     

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).     

Changes in synapses after gamma-irradiation of the rat head

High reactivity and, at the same time, flexibility of interneuronal contacts were observed after exposure of rat head to 2-100 Gy radiation. At high doses (200-400 Gy) radiation-induced changes played a major role in the development of the cerebral form of radiation sickness. A complete asynapsis is probably one of the causes of the animals death "under the ray" (irradiation of the head with a dose of 1000 Gy).     

Quantitative regularities of development of endogenous infection in irradiated organism (survey of literature)

Statistical analysis of data from the literature and the author's own experimental results was carried out in order to reveal functional dependence between the dose of irradiation and the development of endogenous infection in an irradiated organism. Direct linear dependence was established between the dose of irradiation and the severity of endogenous infection at doses causing death from the "bone-marrow" syndrome in acute radiation sickness. In the case of death from the "intestinal" syndrome, inverse linear dependence can be observed between the dose of irradiation and the culture yield of microbes from internal organs. In this case, the pathological effect on the organism is due to bacterial endotoxins formed during disintegration of microbial cells in the organism. Endogenous infection and endotoxinaemia essentially aggravate the course of acute radiation disease. The importance of endogenous infection in death of the organism is neutralized after irradiation in doses causing death "under the ray".     

The RBE of 0.85-MeV neutrons in the intestinal form of radiation sickness in guinea pigs

Relative biological effectiveness (RBE) coefficient of 0.85 MeV neutrons was 1.87 in comparison with 0.66 MeV gamma radiation (137Cs) when estimated by the death rate of guinea pigs with intestinal form of radiation sickness. LD50/5 was 5.9 and 11.06 respectively. Features of the mortality rate dynamics, clinical picture and pathoanatomical changes are discussed.     

Effect of different doses of ionizing radiation on the binding of prostaglandin E2 in mouse tissues

The effect of various radiation doses on membrane reception of prostaglandin E2(PGE2) of spleen, small intestine, brain, and liver cells of mice was studied in dynamics. Irradiation of the animals with doses producing bone marrow, intestinal and cerebral forms of radiation sickness was shown to change specific binding of PGE2 to cell membranes of both radiosensitive tissues and a relatively radioresistant organ, the liver.     

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.     

Histamine release in acute anaphylactic enteropathy of the rat

Investigations into the role of allergic enteropathy in acute and chronic intestinal inflammation have been hampered by the lack of objective confirmation for intestinal mast cell activation. Utilizing an established model of acute allergic enteropathy in the rat, we report the enhanced intraluminal recovery of the mast cell mediator histamine after in vivo antigen challenge in sensitized animals. The enhanced histamine recovery is dose dependent, antigen-specific, and restricted to that segment of bowel challenged, thus confirming local intestinal anaphylaxis. The progression of histologic enteropathy is documented and shown to correlate with the entry of mast cells into the intestinal lumen during, but not before, the anaphylactic response. Pretreatment of the sensitized animal with prostaglandin E2 or doxantrazole, but not cromolyn, significantly inhibits the anaphylactic response.     

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.     

Histology and histochemistry of the seal ovaries and the age-related changes in the ovaries of the Greenland seal]

Histological and histochemical methods were used to study the ovaries of Greenland seal (Pagophoca groenlandica) from birth-time up to 30 years of age and mature females of Phoca vitulina and Erignathus barbatus. The ovary of the new-born Greenland seal has fetal medullary substance which is a provisory endocrinous gland producing not only sex hormones but also corticosteron. In other species of seals the intestinal cells of the medullary substance are the equivalent of this gland. Within 3-4 weeks after birth the reduction of the fetal medullary substance is completed, it is substituted by the connective tissue and the ovary acquires its typical structure. The rest of the fetal medullary substance is in the depth of the cortex and near the infundibulum of the ovary as lipofuscincontaining cells. When the maturation period approaches, the process of the follicle atresia regularly changes: the epithelium dies quicker, and the multiplication of intestinal cells increases. The ovaries of seals are rich in interstitial cells. Their amount cyclically changes. The cells producing steroid hormones always well hydrolize AS naphthyl-phosphates, the reaction with glycerophosphate is more variable. The connective tissue is poor in acid mucopolysaccharides, its amorphous substance in the ovary cortex is rich in protein. Senile changes of the ovary are noticed in the seal beginning from 20 years of age.     

Cellular composition of structural components of the lymph nodes of rats during rehabilitation after dimethyl sulfate poisoning

By means of microanatomical methods the inferior tracheobronchial lymph nodes have been investigated in 48 Wistar rats in 2 weeks and 3 months after discontinuance of inhalation of dimethylsulfate (DMS) vapours for 2 and 14 days by the animals in concentration 2.0 mg/m3, that is to say during rehabilitation period. Comparison of relative parameters of the structural components areas and cell composition of the lymph nodes has been carried out. During rehabilitation period after DMS inhalation for 2 days the cortical and medullary areas in histological preparations do not essentially differ from corresponding parameters of an acute experiment (2 days, 2.0 mg/m3, without rehabilitation). Amount (%) of cells with mitotic figures in the lymphoid nodules++ increases in 2 weeks and in 3 months. Contents of poorly differentiated cells during rehabilitation periods increase in the cortical plateau, but keeps nearly at the same low level as during the acute experiment in the lymphoid nodules++. In 2 weeks after DMS influence for 14 days, the cortical and medullary area in the histological preparations reach the control levels. In the lymphoid nodules++ a relative amount of reticular, poorly differentiated, mitotically dividing cells increases, and in the medullary cords contents of middle and small lymphocytes become greater in comparison with the acute experiment (14 days, 2.0 mg/m3, without rehabilitation).(ABSTRACT TRUNCATED AT 250 WORDS)     

NMR spectroscopy based metabolic profiling of urine and serum for investigation of physiological perturbations during radiation sickness

Radiation accidents are rare events that induce radiation syndrome, a complex pathology which is difficult to treat. In medical management of radiation victims, life threatening damage to different physiological systems should be taken into consideration. The present study was proposed to identify metabolic and physiological perturbations in biofluids of mice during different phases of radiation sickness using ¹H nuclear magnetic resonance (¹H NMR) spectroscopy and pattern recognition (PR) technique. The ¹H NMR spectra of the biofluids collected from mice irradiated with 5 Gray (Gy) at different time points during radiation sickness were analysed visually and by principal components analysis. Urine and serum spectral profile clearly showed altered metabolic profiles during different phases of radiation sickness. Increased concentration of urine metabolites viz. citrate, α ketoglutarate, succinate, hippurate, and trimethylamine during prodromal and clinical manifestation phase of radiation sickness shows altered gut microflora and energy metabolism. On the other hand, serum nuclear magnetic resonance (NMR) spectra reflected changes associated with lipid, energy and membrane metabolism during radiation sickness. The metabonomic time trajectory based on PR analysis of ¹H NMR spectra of urine illustrates clear separation of irradiated mice group at different time points from pre dose. The difference in NMR spectral profiles depicts the pathophysiological changes and metabolic disturbances observed during different phases of radiation sickness, that in turn, demonstrate involvement of multiple organ dysfunction. This could further be useful in development of multiparametric approach for better evaluation of radiation damage as well as for medical management during radiation sickness.