Phase changes in the permeability of the mouse blood-brain barrier after uneven gamma-irradiation

Two phases of changes in blood-brain-barrier permeability for sour fuchsin have been observed in the early period after head or body irradiation at 2.58 C/kg: an increase (up to 2 h) and a decrease (from 2 to 6 h). The correlation between the decrease in BBB permeability and the frequency of clinical manifestations of radiation disease has been established. BBB permeability progressively increased later after head irradiation (24-120 h) which was indicative of its absolute dysfunction. The changes observed may reflect redistribution of fluid and electrolytes in the vascular bed and tissues leading to the onset of brain tissue edema.     

Effect of low-level chronic x-rays on the hemolytic stability and population composition of peripheral blood erythrocytes

A study was made of the haemolytic stability and population composition of peripheral blood erythrocytes of rats chronically exposed to X-radiation of 0.258 mC/kg/day during 30 days. Haemolytic stability of erythrocytes changed at cumulative doses of 2.58, 5.16 and 7.74 mC/kg. Percentage of some erythrocyte fractions obtained by fractionation in a sucrose density gradient was found to change after irradiation with cumulative doses of 5.16 and 7.74 mC/kg.     

Therapeutic effect of vegetable oils and ubiquinone-9 on radiation injuries

The comparison was made of the protective (the administration 3 h before irradiation with a dose of 7.3 Gy) and therapeutic (the administration immediately and later after exposure) effects of soya oil (150 mg/kg) and oil solution of ubiquinone-9 (100-200 mg/kg) on survival of exposed rats. It was shown that soya oil and ubiquinone-9 increased the survival rate of rats when administered before and, to a lesser extent, immediately after irradiation. Corn oil administered immediately after exposure increased the survival rate as well. DMF for the therapeutic effect of soya oil solution of ubiquinone-9 was 1.08.     

Effect of gamma-irradiation on the enzyme activity of cerebrospinal fluid lymphocytes in dogs

Cytochemical activity of succinate dehydrogenase (SDG), L-glycerophosphate dehydrogenase (L-GPDG), lactate dehydrogenase (LDG), and glutamate dehydrogenase (GDG) increased immediately after total-body irradiation with a dose of 129 mC/kg. After 2 h, LDG activity only returned to the control level. Irradiation of the head with the same dose caused less pronounced changes. Changes caused by lethal irradiation (1290 mC/kg) were different: there was an increase after exposure of the abdomen and a decrease in the activity of SDG and L-GPDG after irradiation of the head.     

Regenerative effects of tetrachlorodecaoxide in BD IX rats after total-body gamma irradiation

Tetrachlorodecaoxide (TCDO) was tested for its effects in BD IX rats when combined with a single dose nearing LD50 of total-body irradiation (gamma rays, 60Co). In pilot tests we found that TCDO administrations prior to or immediately after irradiation led to a very high mortality rate (up to 90%), whereas the initiation of TCDO treatment on Day 2, 3, or 4 after irradiation lowered the death rate noticeably, with optimum results when TCDO application was started on Day 4. In our major experiment on 100 BD IX rats, it was demonstrated that the following treatment schedule considerably decreased the death rate (from 44 to 4%): 15.5 mumol TCDO/kg body wt/day on Days 4-6 after irradiation and 7.75 mumol/kg body wt/day on Days 7-11. The animals treated with TCDO showed only mild anemia in the peripheral blood, accompanied by reticulocytosis and low-grade leukocytopenia. Examination of the bone marrow on Day 12 after irradiation revealed X-ray-induced agranulocytosis in the animals that had received only physiological saline solution, whereas in the bone marrow of the animals treated with TCDO there was erythropoiesis as well as myelopoiesis. In addition, the degree of hair loss and depigmentation occurring about 1 month after irradiation was considerably reduced by TCDO. From these results it can be postulated that TCDO has two different effects: as an oxygen donator it causes radiosensitization in the tissue when given before or immediately after irradiation; as an agent stimulating phagocytes and tissue regeneration, it promotes regeneration very effectively when damage is already evident in the tissue.     

Activity of antioxidant system enzymes and lipid peroxidation product content in the liver and thymus of rats in the early stages of irradiation]

The activity of enzymes of the antioxidation system and the content of some lipid peroxidation products in the liver and thymus of irradiated (0.21 C/kg) rats have been investigated. Glutathione reductase and glutathione transferase activity in the liver and thymus of rats decreased during the first 24 h after irradiation. There was a phase change in the catalase activity during the initial postirradiation period. The content of malonic dialdehyde increased immediately after irradiation and somewhat decreased during the first 24 h. In 24 h, there observed a radiation-induced increase in the diene conjugate content in the liver and thymus of rats, against the background of low activity of such antioxidation system enzymes as glutathione transferase, glutathione reductase and catalase.     

Estradiol administration and the sexual activity of castrated male rhesus monkeys (Macaca mulatta)

To examine whether estradiol might be effective in maintaining sexual behavior after castration or after testosterone withdrawal, we have observed male rhesus monkeys during daily 1-hr tests alternately with each of two ovariectomized, estradiol-treated females (four males, four females, eight male-female pairs, 798 tests). Estradiol (2-5 micrograms/kg sc/day) or vehicle was administered in counterbalanced order immediately after castration and again immediately after withdrawal of testosterone propionate treatments (800 micrograms and 1.6 mg sc/day). There were no significant differences in behavior during vehicle and estradiol treatments to indicate that estradiol helped to maintain male sexual activity. Instead, estradiol treatment tended to interfere with the capacity to intromit. This supported the results of other studies, namely, that the systemic administration of estradiol does not enhance the sexual behavior of castrated male macaques, and raises questions about the role of both aromatization and estrogen receptors in the male primate brain.     

Postradiation changes in the systems of active ion transport in the CNS. Na,K-ATPase

A study was made of the effects of irradiation with lethal (0.31 C/kg) and superlethal (12.9 C/kg) doses on Na,K-ATPase activity of various membrane formations in rat brain cortex. The results obtained indicated a significant increase in the activity of the enzyme at different times after irradiation.     

Strain-Dependent Differences in Locomotor Activity after Local Brain Irradiation with 30 GyE of Carbon Ions.

This study investigated strain differences in brain damage among male A/J, C57BL/6JNrs and C3H/HeNrs mice after local brain irradiation. Whole brains were irradiated with a single dose of 30 GyE carbon ion beams and then locomotor activity was determined as body heat of each animal. The daily locomotor activities of untreated mice differed among strains. Non-irradiated C57BL/6JNrs mice were more active than A/J mice. This variance became more obvious immediately after irradiation, when the activity of A/J and C3H/HeNrs mice diminished, whereas that of C57BL/6JNrs mice increased at the beginning of the active phase and remained elevated for three days after irradiation. The altered activities of all three strains of irradiated mice gradually recovered to normal within three to four days.     

Treatment of Irradiated Mice with High-Dose Ascorbic Acid Reduced Lethality

Ascorbic acid is an effective antioxidant and free radical scavenger. Therefore, it is expected that ascorbic acid should act as a radioprotectant. We investigated the effects of post-radiation treatment with ascorbic acid on mouse survival. Mice received whole body irradiation (WBI) followed by intraperitoneal administration of ascorbic acid. Administration of 3 g/kg of ascorbic acid immediately after exposure significantly increased mouse survival after WBI at 7 to 8 Gy. However, administration of less than 3 g/kg of ascorbic acid was ineffective, and 4 or more g/kg was harmful to the mice. Post-exposure treatment with 3 g/kg of ascorbic acid reduced radiation-induced apoptosis in bone marrow cells and restored hematopoietic function. Treatment with ascorbic acid (3 g/kg) up to 24 h (1, 6, 12, or 24 h) after WBI at 7.5 Gy effectively improved mouse survival; however, treatments beyond 36 h were ineffective. Two treatments with ascorbic acid (1.5 g/kg × 2, immediately and 24 h after radiation, 3 g/kg in total) also improved mouse survival after WBI at 7.5 Gy, accompanied with suppression of radiation-induced free radical metabolites. In conclusion, administration of high-dose ascorbic acid might reduce radiation lethality in mice even after exposure.     

Modifications by BCG of the mortality of the irradiated mouse]

Freeze-dried Bacillus Calmette Guerin (B.C.G.) of Institut Pasteur was given by intravenous route to mice at 1,2 and 4 mg/kg before and after gamma irradiation of animals by 1 000 rad. B.C.G. 1 mg/kg injected the day or the day after irradiation has a protective effect (mortality reduced from 77% for controls to 58% and 50% for treated mice). B.C.G. given before irradiation in single or double doses increased mortality.     

Effect of choline on the DNA supramolecular complex in rats and their survival following gamma irradiation

The injection of choline-chloride (200 mg/kg) to rats 15 min before 6 Gy irradiation was shown to increase their survival rate over a period of 30 days, to prolong their average life, and to promote the complete restoration of elastoviscosity of DNA supramolecular complexes in thymus, spleen, liver and brain. When administered immediately after irradiation the drug increased the survival rate of rats.     

Effect of gamma irradiation on brain enkephalin hydrolase activity in the rat

A study was made of the effect of different radiation doses on the brain enzymes degrading enkephalins. Enkephalin aminopeptidase activity decreased during the first 60 min following irradiation with a dose of 774 X 10(-4) C/kg and increased after a dose of 3096 X X 10(-4) C/kg; enkephalinase A exhibited opposite changes. 48 hr after irradiation, enkephalin aminopeptidase activity exceeded the normal level, and no significant changes occurred in encephaliase A activity irrespective of the radiation dose.     

Thermal Reversal of Ultraviolet-Irradiation Damage in Salmonella typhimurium

Effects of ultraviolet irradiation on lysogenic and nonlysogenic Salmonella typhimurium grown at 25 C are partially reversed by shifting cultures to 43 C immediately after irradiation.     

Jejunal crypt stem-cell survival after fractionated gamma-irradiation performed at different dose rates

Jejunal crypt survival after fractionated total body irradiation of C3H mice given at dose rates between 1.2 and 0.08 Gy/min was studied and the results analysed according to the linear quadratic model. Whereas alpha was independent of dose rate beta decreased with dose rate to approach zero at about 0.01 Gy/min. During the period of recovery, sublethal damage from doses given at high dose rate interact with low dose rate irradiation given immediately after, and increases its effectiveness.     

Ways of apoptosis development in human lymphocytes, induced by UV-irradiation

The level of DNA damage and cytochrome c content in human lymphocytes in the dynamics of apoptosis induced by UV light (240?C390 nm) at doses of 151, 1510 and 3020 J/m² is studied. DNA fragmentation is revealed in 20 h after UV irradiation of lymphocytes at doses mentioned above. It is shown that DNA damages (single strand breaks) appear immediately after UV irradiation of lymphocytes at doses of 1510 and 3020 J/m² (comets of C1 type) and reach their maximum 6 h after cell modification (comets of C2 and C3 types). It is concluded that p53-dependent and receptor caspase pathways are involved in apoptosis development in the human lymphocytes, modified after UV irradiation.     

Ethanol-induced hypothermia and ethanol consumption in the rat are affected by low-level microwave irradiation

Microwave irradiation of rats by circularly polarized, 2,450-MHz, pulsed waves (2-μs pulses; 500 pps) was performed in waveguides to determine effects on ethanol-induced hypothermia and on ethanol consumption. Rats injected intraperitoneally with ethanol (3 g/kg in a 25% v/v water solution) immediately after 45 min of microwave irradiation exhibited attenuation of the initial rate of fall in body temperature, which was elicited by the ethanol, but exhibited no significant difference in maximal hypothermia as compared with that of sham-irradiated rats. Microwave irradiation did not affect the consumption of a 10% sucrose (w/v) solution by water-deprived rats. However, it enhanced the consumption of a solution of 10% sucrose (w/v) + 15% ethanol (v/v) by water-deprived animals. These results were obtained at a specific absorption rate (SAR) of 0.6 W/kg, which rate of energy dosing would require a power density of 3–6 mW/cm² if exposure of the animals had occurred to a 12-cm plane wave.     

Inhibition of Prechill-induced Dark Germination in Sorghum halepense (L.) Pers. Seeds by Phytochrome Transformations

A 10 C dark prechilling of johnsongrass [Sorghum halepense (L.) Pers.] seeds, when terminated by a 2-hr, 40 C temperature shift, potentiates about 40% germination at 20 C in darkness. Irradiation of the seeds before, during, and at the end of prechilling with far red light reduces the subsequent germination, although red irradiation after the far red can overcome some of the inhibition. However, either brief red or far red irradiation given immediately after the temperature shift inhibits subsequent germination by one-third to one-half. The results suggest that the far red-absorbing form of phytochrome is a factor in the prechill-induced dark germination and that phytochrome participates in the inhibition of germination by irradiations immediately after the temperature shift.     

Induction of single-strand breaks and interstrand cross-links in liver DNA after the administration of 2-acetylaminofluorene and trans-4-acetylaminostilbene to rats

2-Acetylaminofluorene (AAF) or trans-4-acetylaminostilbene (AAS) was orally or intraperitoneally administered to female Wistar rats. DNA from liver cells was analyzed for single-strand breaks by the alkaline elution assay. Only borderline effects were observed with doses (100 μMol/kg) used in animal carcinogenesis experiments. Even high doses of AAF (1,000 μMol/kg) were not effective. Methyl methanesulfonate (MMS) in vivo and gamma irradiation in vitro were shown to produce dose-dependent DNA single-strand breaks (positive control). Only a marginal effect was obtained with 100 μMollkg MMS. The elution rate of DNA was increased by a factor of 34 in liver cells in vitro with 400 rad of gamma irradiation. Only a fraction of this rate could be demonstrated immediately after irradiation in vivo, and no lesions were found two hours later. This strongly indicates the rapid repair of single-strand breaks. Additional experiments showed that AAS, a nonhepatocarcinogen, produced more interstrand cross-links in the rat liver DNA than did AAF.