The brain phospholipids following the irradiation of animals at a high dosage

In experiments with albino mice, rats and guinea pigs the effect of ionizing radiation (100 Gy) on brain phospholipids and their fatty acids has been investigated. Upon the development of manifest behavioural disturbances (2 h after irradiation) phospholipid molecules degrade insignificantly. Some changes in the relative content of phospholipids and their fatty acids are mainly found in the rat synaptosomal fraction: this may be responsible for the disturbances in the sensitivity of the receptor apparatus of cell membranes.     

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).     

The effect of ionizing radiation at superhigh dosages on the ATP content in the rat brain

The ATP content of rat brain was shown to decrease considerably (20-60%) during the first minutes following high-energy electron irradiation with doses of 300 and 500 Gy. A transient nature of changes and a more pronounced decrease in ATP with increasing radiation dose and manifest neurologic disturbances indicate that the energy metabolism is involved in the pathogenesis of early neurologic disturbances in animals.     

The dynamics of the rats higher nervous activity disturbances after total influence of electrons and gamma-rays in doses 5-100 Gy

The dynamics of using of stabilized motor defensive conditioned reflex of active avoidance in "shuttle-box" in rats after total influence of high energy electrons and of gamma-rays in doses 5-100 Gy were investigated. The quality structure of higher nervous activity disturbances after the influence of these kinds of ionizing radiation was identical. Therefore the tendency to disturbances aggravating after the electron radiation influence in the periods of the initial depression and of relatively normalization was revealed, especially after the irradiation in dose 50 Gy. The effective compensation of the functional disturbances in the central nervous system at the first 5-10 min after irradiation was after influence of electron radiation in doses about 30 Gy and after the influence of gamma-radiation in doses about 50 Gy. The irradiation of rats in doses 10 Gy and 5 Gy caused qualitative different dynamics of radiation disturbances in rats higher nervous activity. The differences in rats higher nervous activity after influence of electron and of gamma-radiation in these doses did not manifest distinctly.     

Physiological and molecular studies on the effect of gamma radiation in fenugreek (Trigonella foenum-graecum L.) plants

This experiment assessed the biochemical changes in fenugreek plants exposed to gamma radiation. Two pot experiments were carried out during two growing seasons of 2015 and 2016. Seeds were subjected to five doses of gamma irradiation (25, 50, 100, 200 and 400?Gy) and were immediately planted into soil pots in a greenhouse. The experimental analysis was performed in M₁ and M₂ generations. Significant differences between irradiated and control plants were detected for most studied characters in M₁ and M₂ generations. It was demonstrated that low doses of gamma irradiation led to gradually increases in growth, yield characters, leaf soluble protein concomitantly with increases in the contents of phenolic and flavonoids compounds particularly at 100?Gy. These changes were accompanied by a substantial increase in ascorbic acid, α-tocopherol and retinol contents. Proline content was increased under all doses of gamma rays in M₁ generation and the highest amount of proline was obtained at 200?Gy with visible decrease in M₂ generation under the same dose. Meanwhile, the highest dose of gamma radiation (400?Gy) decreased all the studied parameters in both mutagenic generations as compared with control plants. In addition, gamma irradiation doses induced changes in DNA profile on using five primers and caused the appearance and disappearance of DNA polymorphic bands with variation in their intensity. These findings confirm the effectiveness of relatively low doses of gamma rays on improving the physiological and biochemical criteria of fenugreek plants.     

Karyometric characteristics of the rat sensorimotor cortex in non-uniform gamma irradiation

Neurocyte nuclei increase in volume without structural changes in karyoplasm at early times after gamma-irradiation of rat head with doses of 50 to 100 Gy. Irradiation of 200 Gy causes a diminution of the nuclei volume while at a dose of 400 Gy the nuclei do not change their volume. A dose as high as 1000 Gy causes severe changes in the karyoplasm leading to nucleus swelling. At later times (24-72 h), the increase in the nuclei volume is associated with the changes in the karyoplasm structure. At one and the same dose, radiation causes either a decrease (irradiation of the head) or increase (exposure of the body) in the neurocyte nuclei volume. At early times after wholebody uniform irradiation no karyometric changes are detected. The nucleus swelling is more pronounced at lower dose-rates.     

小鼠低剂量辐射损伤模型的初步研究

目的:对小鼠低剂量辐射损伤模型进行初步研究并筛选敏感检测指标.方法:实验分7组,1组为正常组,其余6组用XHA600直线加速器射线照射,每组取一部分小鼠于照射后2、4、8、16h测定红细胞(RBC)、白细胞(WBC)、血小板(PLT)和血红蛋白(HGB)含量;测定小鼠肝脏和脾脏重量及其组织中的超氧化合物歧化酶(SOD)和丙二醛(MDA)含量;剩余小鼠于4周后观察骨髓切片中血细胞变化.结果:照射后4h测定血常规,发现累积辐射0.4Gy组小鼠RBC有降低趋势,WBC、HGB显著降低,PLT显著升高;肝脏、脾脏的湿质量显著降低;小鼠肝脏组织中MDA的含量显著升高、SOD的活力显著降低;4周后小鼠骨髓细胞的病理改变与单次照射剂量相关,单次较大剂量(如0.6Gy)照射对骨髓细胞影响较大,在4周观察期不能自身恢复,而多次累积照射对骨髓细胞病理改变较小.结论:小鼠低剂量辐射损伤模型的最佳造模剂量为累积照射0.4Gy即每次照射100mGy,间隔一天,连续照射4次.     

Effect of ionizing radiation on the aggressive behavior of mice

Changes in the aggressiveness of mice were studied after exposure thereof to 5, 10, 30, 60 and 100 Gy radiation. With doses of 5, 10 and 30 Gy no stable effect on the aggressive behaviour of mice was observed, while doses of 60 and 100 Gy suppressed it drastically. Stress at the time of exposure can enhance the antiaggressive effect of radiation.     

Effect of radiation dose on the recovery of aerobic and anaerobic bacteria from mice

The presence of aerobic and anaerobic bacteria in the blood, spleen, and liver was investigated in mice that were exposed to 7, 8, 9, or 10 Gy 60Co radiation. Microorganisms were detected more often in animals exposed to higher doses of radiation. The number of mice that were culture positive and the number of isolates in one site increased with increasing dose. Bacteria were recovered in mice killed at various times after radiation, in 3 of 100 mice exposed to 7 Gy, in 13 of 100 irradiated with 8 Gy, in 23 of 90 exposed to 9 Gy, and in 34 of 87 irradiated with 10 Gy. The predominant organisms recovered were Escherichia coli, anaerobic Gram-positive cocci, Proteus mirabilis, Staphylococcus aureus, and Bacteroides spp. Escherichia coli and anaerobes were more often isolated in animals exposed to 10 Gy, while S. aureus was more often recovered in those irradiated with 9 Gy. These data demonstrate a relationship between the dose of radiation and the rate of infection due to enteric aerobic and anaerobic bacteria.     

Simulation modelling of the postradiation restoration of the crypt-villus system

Basic principles have been developed for a discrete stochastic simulation model of an elementary proliferative unit of the intestinal epithelium, a "crypt-villus" system. The analysis of the results obtained after a single exposure of the animal's abdomen to 3 and 6 Gy radiation has demonstrated that the dynamics of the number of cells that synthesize DNA in a small intestine crypt of exposed mice depends on the rate of radiation damage repair (50 to 100 h following irradiation). The rate of repair after 6 Gy irradiation is 1.5 times lower that after 3 Gy. The changes in the shape of the labeled mitoses curve, followed up during the postirradiation recovery of the intestinal epithelium, may occur with the time parameters of the cell mitotic cycle being invariable.     

The effects of X irradiation on the metamorphosis and budding of Aurelia aurita

With the aid of the Aurelia metamorphosis test system, the acute and subtle developmental and behavioral effects of X irradiation in the presence and absence of thyroxine on the Norfolk Aurelia aurita were described. Radiation doses were 0 (control), 50, 100, 150, 200, and 400 Gy. Morphology of the ephyrae, and statolith and rhopalia numbers were recorded using the light microscope. Developmental abnormalities of the polyps and ephyrae were recorded with the scanning electron microscope and light microscope. Major findings from this investigation were the absence of rhopalia and statoliths in ephyrae at 150 and 200 Gy, a reduction in pulses per minute in the ephyrae at 100, 150, and 200 Gy, a reduction in ephyrae released at 150, 200, and 400 Gy, and the development of polyp monsters. There was a significantly higher frequency of polyp monsters in the group exposed to thyroxine prior to radiation than in the thyroxine-free group prior to radiation.     

不同剂量的X-射线全身照射对小鼠健康状况及涎腺的影响

目的:通过直线加速器全身照射昆明小鼠建立辐射损伤模型,探索不同放射剂量对小鼠健康状况及涎腺功能和结构的影响。方法:选取八种不同剂量对昆明小鼠行体外全身照射,于照射后一个月内观察小鼠生长情况、体重变化;照射后一周、一个月检测各组小鼠血象的变化;测定放射半数致死剂量;照射后两个月,测定各组小鼠的唾液流量及唾液淀粉酶含量,并对下颌下腺组织切片行HE染色。结果:13Gy和15Gy照射组小鼠的体重逐渐下降,一周后死亡,其余组小鼠体重最终呈增加趋势。X-射线全身照射的半数致死量为10Gy。照射后一周,照射组小鼠的白细胞数目明显降低,与对照组比较有明显统计学差异(P0.01);在其他血象方面,除了7Gy组外,其他照射组与对照组比较也均有统计学差异(P0.05)。照射一个月后,各照射组小鼠的血象均恢复正常。照射后两个月,9Gy组和11Gy组小鼠的唾液流量及唾液淀粉酶含量均显著低于0Gy组,且11Gy组较9Gy组亦明显降低,差异均有统计学意义(P0.05)。随照射剂量的增加,小鼠的下颌下腺腺泡细胞数目逐步减少,结构排列紊乱,组织损伤逐渐加重。结论:X-射线全身照射引起小鼠健康状况受损,免疫功能减低,损伤程度与放射线强度呈剂量依赖性,小鼠半数致死量为10Gy,该剂量适合建立全身放射损伤模型。     

Radiation resistance of motor-defensive conditioned reflexes in rats at different stages of the formation and stabilization of a temporary connection

Disturbances were studied of the motor defensive conditioned reflexes in rats radiated in a dose of 100 Gy at different stages of formation and stabilization of temporary connection. In comparison with consolidated (automatized) conditioned reflexes of active avoidance, early stages of formation and stabilization of the temporary connection are characterized by a relatively low resistance against extreme factors and by deepest disturbances of reproduction in radiated animals. The most probable mechanisms of these disturbances are connected with pathological changes of the nervous processes balance towards an increase of excitability and weakening of internal inhibition. Yet a direct radiation influence on the mechanisms of temporary connection reproduction at the second stage of its consolidation cannot be excluded. The role is shown of the emotional reactivity in the above-described processes.     

The intensity of proteolysis in the peripheral blood lymphocytes of rats in the early period of acute radiation injury

Comparative analysis of biochemical indices that reflect the proteolysis rate in rat peripheral blood lymphocytes in normal conditions and during the first 4-6 h after whole-body single uniform gamma-irradiation with lethal (7.5 Gy) and nonlethal (3 Gy) doses has revealed that the pronounced activation of proteolysis in lymphocytes and the disturbances in the inhibitor/protease balance are characteristic of the severe form of radiation damage with fatal outcome. Simultaneously changes occur in biochemical indices of plasma that reflect a catabolic pathway of metabolism in the whole-body. The absence of similar changes in the blood of the survived animals permits to recommend the biochemical indices under study to be used for early prognosis of the radiation affection outcome.     

The dynamic content of prostaglandins and cyclic nucleotides in the blood of irradiated dogs and monkeys

In experiments with dogs and monkeys a study was made of the dynamics of the content of prostaglandins (PG) and cyclic nucleotides after gamma irradiation. In dogs irradiation with lethal doses (3.1 and 50 Gy) caused a short-term, evidently stress growth of cAMP, PGE and PGF2 alpha levels. At the height of radiation sickness PGF2 alpha and cGMP content decreased considerably. Irradiation of monkeys with a nonlethal dose of 3.2 Gy changed PGE and PGF2 alpha levels to a lesser extent, while concentrations of cyclic nucleotides varied but their ratio remained stable.     

The radiation-modifying capacity of xenogenic apotransferrin for the number of endogenous colony forming units in the spleen of irradiated mice

After intraperitoneal injection of 100 or 198 mg/kg of human serum apotransferrin (apo TF) to mice 1 day before acute exposure to 6 Gy of gamma-radiation, the number of endogenous CFU in spleen (CFUs) increased 2.5 or 2.6 times respectively. At a dose fo 10 mg/kg of the protein only an increasing tendency was found, whereas a dose of 1 mg/kg was inefficient. A dose of 100 mg/kg of BSA did not show any effect suggesting that non-specific immune response to alien antigen did not contribute to apo TF radiomodifying action. The following mechanisms of the apoTF radiomodifying effect are discussed: 1) the ability of the protein to inactivate Fe3+ ions that reduces the consequences of radiation oxidative stress; 2) the stimulation of proliferation of the exposed bone marrow cells by activation of Fe3+ transport or by Ca2+ mediated mechanism of mitogen signal transduction; 3) changing in the content and ratio of cyclic nucleotides by apo TF stimulation of Ca-calmodulin-dependent phosphodiesterase.     

Postradiation motor disorders in rodents as the equivalent of the clinical manifestations of a primary radiation reaction

In experiments with albino mice it was found that during the first hours following gamma irradiation with doses of 10-80 Gy stability of implementation of loading and coordination tests was impaired and hard work endurance decreased. With doses exceeding 100 Gy, cerebral damages were stably manifested. There was a similarity between the postirradiation motor disturbances in animals of various species.     

Modifying effects of neurotropin on post-radiation disorders of neuromediator processes in the autonomic function regulation centers

In experiments on Wistar rats, it was shown that 6 months after exposure to ionizing radiation (X-radiation 0.5 Gy and intraperitoneal 131I 6.5 mCu/kg) the hypothyroid state was accompanied by changes in inhibitory and excitatory mediation that are characteristic of chronic radiation stress in cerebral structures responsible for regulation of autonomic and animal functions and a relative deficiency of the hypothalamopituitary-adrenocortical axis. Application of therapeutic doses of neurotropin 3 months after radiation levelled the pattern of chronic radiation stress and diencephalic disorders that underlie disturbances of some systemic functions of the organism.     

The effect of a low dose of ionizing radiation on the activity of cAMP-dependent phosphodiesterase and protein kinase of chicken thymus in ontogenesis

Dynamics of changes in activities of cAMP-dependent enzymes, phosphodiesterase and protein kinase, were studied in the thymus of intact and irradiated, prior to incubation, (0.05 Gy) chicken embryos and chicks. The changes observed were wave-like. In determining phosphodiesterase activity of irradiated chicken thymocytes during ontogenesis the values were obtained that correlated with the cAMP level and adenylate cyclase activity. It was also shown that the increase in the rate of cAMP-dependent phosphorylation under the effect of low-level radiation corresponded to the cyclic nucleotide content of a cell at different development stages.     

Pencilbeam Irradiation Technique for Whole Brain Radiotherapy: Technical and Biological Challenges in a Small Animal Model

We have conducted the first in-vivo experiments in pencilbeam irradiation, a new synchrotron radiation technique based on the principle of microbeam irradiation, a concept of spatially fractionated high-dose irradiation. In an animal model of adult C57 BL/6J mice we have determined technical and physiological limitations with the present technical setup of the technique. Fifty-eight animals were distributed in eleven experimental groups, ten groups receiving whole brain radiotherapy with arrays of 50 µm wide beams. We have tested peak doses ranging between 172 Gy and 2,298 Gy at 3 mm depth. Animals in five groups received whole brain radiotherapy with a center-to-center (ctc) distance of 200 µm and a peak-to-valley ratio (PVDR) of ∼ 100, in the other five groups the ctc was 400 µm (PVDR ∼ 400). Motor and memory abilities were assessed during a six months observation period following irradiation. The lower dose limit, determined by the technical equipment, was at 172 Gy. The LD50 was about 1,164 Gy for a ctc of 200 µm and higher than 2,298 Gy for a ctc of 400 µm. Age-dependent loss in motor and memory performance was seen in all groups. Better overall performance (close to that of healthy controls) was seen in the groups irradiated with a ctc of 400 µm.