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N G Darenskaia

Publications and source records attributed to N G Darenskaia.

At least 19 recordsLinked to original sources
PubMed2000

[Dynamics of the non-specific reactivity of the organism in time].

Experiments with 10 mongrel rats and dogs showed that individual reactivity of animals to hypobaric hypoxia was same during repeated exposure in two weeks. Investigations of 20 dogs demonstrated relatively permanent types of group reactivity, i.e. hyper-, normal, and hyporeactivity to adrenaline injections every 2 months over a year period. Each type of group reactivity was marked by phase variation in the count of peripheral blood leukocytes with the relation of group mean values unchanged. Analysis of mean values of adaptive levels in 340 subjects with varying individual reactivity over 10 years also pointed to undulation of these values in each group. At the same time, the difference in mean values of this parameter among the groups was kept constant. Hence, the group specific reactivity has a long-range character as determined by testing.

Adaptation, Physiological↗
PubMed2000

[Individual radioresistance and principles of its formation].

Individual variability of resistance to a broad range of ionizing radiation was analyzed. Individual radioresistance depends both on physical (radiation type, dose, and distribution along the body, dose rate) and biological (species, strain, sex, body mass of animal etc.) factors. Individual radioresistance is manifested by specific and nonspecific responses of organism to radiation. Three components of individual radioresistance are stable, semistable and labile. The stable component is genetically determined by species, sex, habitus status and radiosensitivity of cells of critical organs. The semistable component is determined by embryogenetic, early postnatal development and reflected in functional activity of the main regulatory systems of the body. The labile component is a parameter of current functional state of an indviduum. The stable and semistable components characterize inborn whereas the labile component--acquired radioresistance.

Animals↗
PubMed1986

[Prognostication of individual radiation sensitivity of animals, based on the use of a mathematical method of object classification].

A statistical method of object classification based on the use of linear discriminant analysis, was employed to solve the problem of prediction of the outcome of acute radiation disease. In experiments on 23 monkeys irradiated at a dose of 5.3 Gy 14 animals had survived and 9 perished. The initial state and early response (in 5 h) to gamma-beam radiation were assessed. The total number of the analyzed parameters was 16. According to the experimental results an integral index--discriminator--was computed for each object. Values for the survivors ranged within 136.1-151.3, and for 9 more radiosensitive animals the values of discriminators turned out to be higher (151.9-168.7). The procedure of prognosis was the following. 23 monkeys were randomly divided into 2 groups (using the table of random numbers). The 1st group (a study sample) included 13 animals, of them 8 survived and 5 perished. The 2nd group (a control predictor sample) included 10 animals, of them 6 survived and 4 perished by the end of the experiment. The authors described 3 variants of a random selection of the animals both for the 1st and 2nd groups. The results of prognosis were compared with the experimental results. Erroneous prognosis for each variant was 10, 0 and 20%, respectively.

Algorithms↗
PubMed1986

[Possibilities of prognostication of individual radiation sensitivity].

Proceeding from the concept of individual radiosensitivity as a sign of total reactivity 3 directions in a study of its possible prediction were considered: establishing correlation between separate indices characterizing the initial state and total radiosensitivity; correlation between body reactions to non-radiation exposures and subsequent irradiation; comparison of total radiosensitivity to irradiation at a small dose and subsequent irradiation at LD50. The following indices were used for the evaluation of the basal status of the body: oxygen consumption level, body mass increase rate, the level of water and basal metabolism, peripheral blood indices, body temperature, basal indices of the functional adrenocortical activity, the state of the cardiovascular system. The following non-radiation stress-exposures were used: physical exercise, constant magnetic field, starvation, hypoxia, and adrenaline administration. A V-type dependency was established for most investigated indices of the basal status and reaction of the body to non-radiation exposures. The utmost radioresistance was shown by animals in whom the basal indices or their reaction to non-radiation exposure approximated the average group level. The third direction: comparison of radiosensitivity and radiation damage--was analyzed by comparing the reaction of cerebral biocurrents to radiation exposure at a small dose with subsequent damage of the body following irradiation at a lethal dose. The accuracy of predicting the outcome of radiation injury by some of the indices varied from 65 to 80%. In some indices of the basal status and reactivity evaluation it reached 85-90%.

Animals↗
PubMedDate not supplied

[Quantitative regularities for clinical manifestations of radiation injury in large-sized laboratory animals exposed to supralethal radiation doses Gamma-neutron and electron biological effectiveness as influenced by exposure conditions and dose distribution in the animal body].

The damaging effect of gamma-neutron radiation over a wide neutron-energy range, with average values of 0.37 and 1.2 MeV, and that of electrons with an average electron energy of 25 MeV have been compared in dogs and two monkey species exposed to a broad range of supralethal doses. An analysis of absorbed dose distribution in critical organs and systems has shown the highest effect of gamma-neutron radiation with an average neutron energy of 1.2 MeV. With severity of early clinical manifestations of damage as a criterion, electrons have appeared the most effective. The radiosensitivity of animals grew in the order as follows: dog-->M. fascicularis-->P. hamadryas.

Animals↗
PubMedDate not supplied

[A possibility to predict the severity of individual damage following the exposure to supralethal radiation dosage. Prediction by early radiation response ].

The experiments on dogs and monkeys have shown that the severity of radiation sickness following the exposure to supralethal radiation doses can be predicted by early response of an individual. For such prediction, the most informative criteria include general severity of clinical manifestations during primary radiation response and evaluated within a few post-damage hours, the degree of tension in cardiac rhythm control, the cortisol level, the endocrine status index.

Animals↗
PubMedDate not supplied

[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.

Animals↗
PubMedDate not supplied

[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.

Animals↗
PubMedDate not supplied

[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.

Animals↗
PubMedDate not supplied

[Prediction of the severity of damage and disruption of work ability in reaction of the body to alcohol load prior to radiation exposure in the superlethal range].

In experiments on 121 white non-linear rats, 44 Papio hamadryas and 29 Macaca fascicularis, animals' reactions on the alcohol impact (AI) and following exposure to supralethal doses were compared. The animals were intravenously injected with 5% ethanol in the glucose solution, 2.1 g/kg for rats and 0.46-0.51 g/kg for monkeys. Monkeys' response to AI was scored in four-point scale by estimating of abnormalities in motor activity, coordination of motion and changes in conditioned reflex activity. It was shown that changes in the ability of alcohol-injected rats to perform the learnt exercises in the "jump box" could be used for prediction of their response to the exposure to supralethal doses of ionizing radiation. Observing the AI-response in monkeys along with a method "function of spying for moving object" made possible to predict not only a general degree of loss of working ability but also to estimate individual impairments of spying functions. In 65% monkeys high similarity of the reactions to AI and ionizing radiation was observed.

Alcohols↗
PubMedDate not supplied

[Reaction of the blood forming system of the dogs to acute radiation exposure (by the SRC-Institute of biophysics data bank)].

At present time in the SRC--Institute of Biophysics the data bank containing the information on the reactions of 431 dogs to radiation exposure in a wide range of doses has been created. By the results of 4299 blood tests reporting a leukocyte content, including 2509 tests reporting a blood formula, the individual peculiarity of the peripheral blood reaction in dogs were analyzed. Dose dependencies for the reaction of blood-forming system to radiation exposure to doses in the range from 1.0 to 7.0 Gy were obtained. In comparison with the similar data for humans, the neutrophil content in peripheral blood decreased approximately 1.5-2.0 times faster in dogs than in men, resulting in earlier recovery.

Animals↗
PubMedDate not supplied

[Quantitative regularities and peculiarities of the development of the cerebral form of radiation sickness at fractionated irradiation].

Several peculiarities in manifestations of cerebral form of radiation sickness have been revealed at a fractionated double irradiation with equal and unequal doses per fraction and different intervals between the fractions. A reliable increase in average lifespan of rats irradiated with (100 + 100 Gy) equal doses at 10 and 60 min intervals between two fractions compared to the single radiation exposure to 200 Gy has been obtained. Lifespan of rats irradiated with a total dose greater than 200 Gy in most cases of double exposures with 10 min interval was reliably less than that for animals after a single exposure. The influence of the first dose on the reduction of animal average lifespan increased with fraction dose increasing from 150 to 300 Gy and was most pronounced at the total exposure dose of 400 Gy. Reaction of rats on the repeated irradiation was significantly weakened in comparison with the reaction on the first exposure. At a study of capacitation the interval of 30 min appeared to be more favorable compared to 10 min interval. Importance of a dose value in the first fraction has been demonstrated: the higher this value the worse the capacity of the rats 3 hours after the repeated exposure.

Animals↗