Combined effects of various forms of motor deprivation and gamma irradiation on the higher nervous activity in rats]

Effects of gamma-radiation at a dose of 3 Gy against either antiorthostatic hypodynamia (AOH) or hypokinesia (HK) on formation of the differentiated motor-drinking reflex (DR) were compared. Each of the forms of motor deprivation hindered the elaboration of DR; gamma-irradiation aggravated these disorders. At the same time, AOH led to significantly more severe disturbances in the higher nervous activity including the generalized excitation, pathologic aggressiveness and neurotization of animals. In contrast, hypokinesia stimulated the active elements of behavior which inhibit the passive-defensive behavior and a fear reaction. Therefore, the modifying effect of irradiation becomes apparent only if combined with AOH.     

Time-dependent differential changes of immune function in rats exposed to chronic intermittent noise

Noise is a highly relevant environmental and clinical stressor. Compared to most other experimental stressors, noise is a modest activator of neuroendocrine pathways that mimic the situation in human health where neuroendocrine activation by environmental stressors is often absent or difficult to establish. Little is known about the effects of noise exposure on the immune system. In the present work, the effects of a low-intensity chronic intermittent unpredictable noise regimen on various parameters of immune function was studied. Male wistar rats were exposed to a randomized noise protocol (white noise, 85 dB, 2-20 kHz) for 10 h per day, 15 min per h over a total period of 3 weeks. Control animals were exposed to ambient sound only. Immune function was monitored after 24 h, 7 days, and 21 days of noise exposure. Noise induced several significant changes in immune function in a time-dependent differential pattern involving both immunosuppression and immunoenhancement. After 24 h, serum IgM levels were increased and peripheral phagocytic activity was decreased. Splenic lymphocytic proliferation to mitogens was significantly decreased after 7 days, but slightly elevated after 3 weeks. The activity of splenic NK cells was increased significantly after 24 h and 7 days, but suppressed after 3 weeks. These results show that various parameters of immune function are affected differentially over time in a period of chronic mild noise stress, possibly due to sequential activation of different physiological mechanisms.     

Experimental study of the effect of formaldehyde during embryogenesis on the activity of rat liver enzyme systems in ontogenesis]

Leaf tobacco contains minute amounts of lead 210 (210Pb) and polonium 210 (210Po), both of which are radioactive carcinogens and both of which can be found in smoke from burning tobacco. Tobacco smoke also contains carcinogens that are nonradioactive. People who inhale tobacco smoke are exposed to higher concentrations of radioactivity than nonsmokers. Deposits of 210Pb and alpha particle-emitting 210Po form in the lungs of smokers, generating localized radiation doses far greater than the radiation exposures humans experience from natural sources. This radiation exposure, delivered to sensitive tissues for long periods of time, may induce cancer both alone and synergistically with nonradioactive carcinogens. This article explores the relationship between the radioactive and nonradioactive carcinogens in leaf tobacco and tobacco smoke and the risk of cancer in those who inhale tobacco smoke.     

Structure and properties of the cell nucleus chromatin in the brain of rats exposed to gamma-radiation]

Exposure of rats to radiation in a dose of 1 Gy changes sensitivity of chromatin in the cerebral cortex cells to the action of DNAase 1, which promotes an increase of the DNA hydrolysis level and content of dissolved chromatin fractions. A day after irradiation the chromatin structure restores only partially and then (7-30 days after irradiation) it passes into a new, less compact state. The irradiation changes the chromatin ability to aggregation in the presence of Mg2+ and spermidine.     

Functional activity of rat pancreatic endocrine cells in weightlessness and in a suspended state]

Molecular dynamics calculations have been carried out on a model of the LS3 synthetic ion channel in a membrane mimetic environment. In the absence of an external electrostatic field, the LS3 channel, which consists of a bundle of six alpha-helices with sequence Ac-(LSSLLSL)3-CONH2, exhibits large structural fluctuations. However, in the presence of the field, the bundle adopts a well defined coiled-coil structure with an inner pore of water. The observed structural changes induced by the applied field are consistent with the proposed gating mechanism of the ion channel.     

Effects of prolonged exposure to morphine and methadone on in vivo parameters of immune function in rats

In rats, two 6-week repeated dose oral toxicity studies were performed with morphine (250 and 500 mg/kg food) and methadone (200 and 400 mg/kg food), respectively. Alterations in immune function were studied by assessing primary and secondary immune responses to sheep red blood cells. In addition, the ability to resist challenge with infectious agents was measured in host resistance models employing the parasite Trichinella spiralis and the bacterium Listeria monocytogenes. The primary and secondary antibody responses to sheep red blood cells were not affected by treatment with either morphine or methadone. The clearance of L. monocytogenes bacteria in the spleen was not affected either. Prolonged treatment with morphine, however, resulted in a decrease in host resistance to T. spiralis infection, as indicated by a 1.5-fold increase in numbers of muscle larvae counted in the carcass, but did not affect the T. spiralis-specific IgM, IgG and IgE antibody responses. In contrast to morphine, the methadone-treated animals did not show a significant change in host resistance to T. spiralis. Total serum IgG levels, however, were increased in high-dose methadone-treated animals. Apparently, prolonged administration of morphine to rats resulted in immune suppression, mediating a slight, though biologically relevant, exacerbation of the T. spiralis infection, whereas methadone did not.     

Functional state of the supraepithelial mucous layer of the digestive tract in mice in the postnatal period after irradiation

It was studied the condition of mucous layer of intestine in mice model experiments after ionizing radiation. It were found out the differences in reaction of intestine on radiation in mice at the age of 55 and 95 days. In mice at the age of 55 days at the whole stretch of intestine was marked increased secretion of the polymeric glycoproteins, whereas in mice at the age of 95 days such alterations were marked at smaller degree. In both groups mice was marked increased secretion of bicarbonate after radiation, that is possible to count as characteristic compensative mechanism.     

Protein and ribonucleic acid metabolism in the central nervous system of rats during space flight in the "Kosmos-605" satellite]

On the 2nd postflight day the activity of neutral protamine peptide hydrolase of different compartments of the rat brain did not differ from the control level. With respect to the protein and RNA content and concentration motoneurons of anterior horns of the spinal cord and their glial-cells-satellites of rats exposed to the ground-based synchronous experiment did not differ from those of vivarium controls, except cells of the supraoptic nucleus. That was found on the 2nd and 27th postflight days. On the 2nd postflight day the protein and RNA concentration in neurons decreased and the protein concentration and content in gliocytes lowered; the RNA concentration and content in Purkinje cells of the cerebellum became reduced. On the 27th postflight day the RNA concentration in neurons of the supraoptic nucleus remained diminished whereas the protein content increased; in spinal motoneurons the protein concentration decreased and in adjacent gliocytes the protein concentration and content lowered. All the above changes made no more than 15% of the control values.     

Stress, endocrine, and immune system; stress induces the onset of autoimmune diseases

Previous studies of birth certificates have not fully evaluated how accurately they identify delivery methods that have a historical component, such as repeat cesarean and vaginal birth after previous cesarean (VBAC). The authors used linked Georgia birth certificates for first and second deliveries to examine the accuracy of four reported delivery methods in the second pregnancy: vaginal (without previous cesarean), VBAC, primary cesarean, and repeat cesarean, as well as an indicator of a previous cesarean. From the immediate birth certificates, the delivery method for each of the two births was classified as vaginal (V) or cesarean section (CS), which produced possible sequences of V-V, CS-V, V-CS, and CS-CS. The delivery method for the second births to 106,049 women from 1989 through 1992 was reviewed, taking into account the historical information from the linked certificates regarding the first births. Only 42.0% of women with a CS-V sequence were correctly designated on the second birth certificate as a VBAC; 79.3% of women with a V- CS sequence were correctly designated as primary cesarean. From 1980 through 1988, birth certificates contained a check box indicating a previous cesarean (but no VBAC box). During this period, only 75.5% of 25,491 women with a previous cesarean were so designated on the birth certificate. These findings suggest that cross-sectional vital records data substantially underestimate VBAC and primary cesarean rates.     

Combined effects of caffeine and alcohol during pregnancy on bones in newborn rats

Infections of the urinary tract occur quite frequently in patients of both sex in the practice as well as in the hospital. They are caused mainly by bacteria. However, virus- and significant fungus-infections of the kidney and the urinary tract are observed due to acquired immuno-suppression or induced by the physician. The current knowledge about this problem is still insufficient. Obtaining a careful history, the physical examination and biochemical analysis are still of great value for a successful treatment. Besides the drug therapy, the physiological immunological mechanisms should be activated by unspecific procedures. If they are the only risk factor, urinary tract infections including chronic courses never lead to kidney failure necessitating a dialysis.     

Voluntary exercise influences behavioral development in rats exposed to alcohol during the neonatal brain growth spurt.

Children exposed to alcohol prenatally may suffer from severe brain damage, expressed as a variety of behavioral problems, including hyperactivity and learning deficits. There is a critical need to identify effective treatments for fetal alcohol effects. Physical exercise enhances cognitive ability and increases neurogenesis in the hippocampus, a brain area important for learning and memory. Thus, the present study examined whether physical exercise might reduce the severity of alcohol-induced behavioral alterations. Sprague-Dawley rats were intubated with 5.25 g/kg/day ethanol during the third trimester equivalent (postnatal days [PDs] 4-9). Intubated sham control and nontreated controls were included. From PD 21 to PD 51, half of the subjects were given access to running wheels. On PD 52, subjects were tested on the Morris water maze, and on PD 60, open field activity levels were measured. Morris maze performance was significantly impaired among ethanol-exposed subjects; exercise significantly improved performance of all groups. Similarly, ethanol-exposed subjects were overactive in the open field, an effect attenuated with exercise. In sum, these data suggest that exercise may increase neuronal plasticity not only in controls, but also in subjects exposed to alcohol during development. (PsycINFO Database Record (c) 2010 APA, all rights reserved)