Electron microscopic radioautographic study on the syntheses of DNA, RNA and protein in the livers of aging mice

The syntheses of DNA, RNA and protein in the livers of aging mice was studied by electron microscopic radioautography using radioactive precursors. Labeling with³H-thymidine was observed in the nuclei of some hepatocytes at various prenatal and postnatal ages. The percentage of labeled cells decreased after birth, then slowly fell to the lowest value at 2 years. The silver grains with³H-uridine labeling were observed in both the nuclei and cytoplasm of hepatocytes at various ages. There was a peak in uridine labeling at 14 days, and then it slowly decreased until old age. The number of silver grains with³H-leucine labeling in the cytoplasm of hepatocytes was small. It increased after birth, reached the maximum at 1 month, and continued to decrease with aging.     

Electron microscopic radioautographic study on the nucleic acids and protein syntheses in the aging mouse testis

The ultrastructural difference between³H-thymidine labeled and unlabeled germ cells in mouse testis was observed by electron microscopic radio-autography. The RNA and protein syntheses in the seminiferous tubules of aging mice were also studied using³H-uridine and leucine radioautography. At embryonic day 19, the Sertoli cells and myoid cells labeled with³H-thymidine were often observed. The gonocytes labeled with³H-thymidine that were not rich in cell organelles appeared from the early postnatal stage. The silver grains were located mainly over the nuclei of labeled gonocytes, but a few were over the mitochondria. The labeling index of spermatogonia for³H-thymidine rapidly increased from 2 weeks on, and stayed relatively constant until old age. The labeling indices of the other two kinds of cells, i.e., Sertoli and myoid cells, decreased to low levels with aging, while these cells continued RNA and protein syntheses through aging, as detected by the incorporation of³H-leucine and uridine.     

Effect of corticosterone on the macroergic pool and membrane permeability in sections of rat hippocampus

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 12, pp. 604–607, December, 1993     

Diurnal rhythmic fluctuations of the oxygen affinity of hemoglobin in premature infants

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 10, pp. 425–428, October, 1993     

Kinetic characteristics of the energy production system in rat brain under conditions of posthypoxic encephalopathy and its correction withBergeniae crassifolia extract

Posthypoxic encephalopathy is characterized by inhibition of the succinate oxidase stage in cerebral energy production. When administered to rats exposed to hypoxia,Bergeniae crassifolia extract reduced mortality and restricted the inhibition of rapid metabolic cluster reactions. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 1, pp. 73–76, January, 2000     

Incorporation of thymidine-H3 into DNP of rat tissues after a single injection of DNA

Injection of homologous DNA into rats caused increased incorporation of thymidine-H³ into DNP of the bone marrow, spleen, thymus, and mucous membrane of the small intestine 24 h after the the injection. This effect was not found on the third day.Moscow. (Presented by Academician of the Academy of Medical Sciences of the USSR P. D. Gorizontov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol. 81, No. 5, pp. 533–534, May, 1976     

Effect of benactyzine and arecoline on Mg2–-ATPase activity and content of Ca2– and Mg2– ions in the rat brain

The effect of the central cholinolytic benactyzine (40 mg/kg) and of the cholinomimetic arecoline (2.5 mg/kg) on activity of Mg^2–-dependent ATPase was studied and the content of Ca^2– and Mg^2– ions determined in rat brain. Benactyzine and arecoline caused biphasic changes in the activity of the enzyme and content of the electrolytes. It is concluded that inhibition of the enzyme is linked with the accumulation of Ca^2– ions and its activation with an increase in the concentration of Mg^2– ions in brain tissue. It is suggested that benactyzine and arecoline exert their influence on the liberation and retention of neuromediators in the tissue depots through these effects.(Presented by Academician of the Academy of Medical Sciences of the USSR V. V. Zakusov.) Translated from Byulleten' Éksperimental'noi Biologii i Meditsiny, Vol.84, No. 9, pp. 306–309, September, 1977.     

Effect of opioid lymphostimulation on the microcirculation in pial vessels of the ischemized rat brain

The response of pial vessels to i.p. administration of leu-enkephalin (at 40 μg/kg) is studied biomicroscopically in the control, before and after bilateral occlusion of the common carotid arteries. Leu-enkephalin causes chiefly the narrowing of pial arterioles and does not affect venule diameter. The effect of leu-enkephalin on occlusion of the common carotid arteries manifests itself in the preservation of circulation stability, the narrowing of some arterioles, and in the decrease of the degree of dilation. These changes occur against the background of lowered arterial pressure, bradycardia, increased local circulation in the brain cortex by 50–70%, intensification of the lymph flow in micro- and macrovessels, and the absence of mortality of animals in the first hours of occlusion of the arteries. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 119, N ^o 1, pp. 100–105, January, 1995 Presented by G. N. Kryzhanovskii, Member of the Russian Academy of Medical Sciences     

Impact of ammonium chloride in a toxic dose on the bioelectrical activity of rat brain

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 116, N ^o 7, pp. 19–21, July, 1993     

Effect of asphyxia on adenylate cyclase activity in cat brain cortex

Effect of 1–5-min asphyxia on adenylate cyclase activity in cat brain cortex is studied. Adenylate cyclase activity is measured in cortex specimens obtainedex vivo after 1, 2.5, and 5 min of asphyxia, and 30 and 60 min of reoxygenation by radioassay. Stimulating effects of norepinephrine and NaF on adenylate cyclase activity are assessed. Five-min asphyxia induces phasic changes in adenylate cyclase activity: on the 1st min basal activity of the enzyme increases by 97%, after 2.5 min it returns to the initial level, and increases again by 55% on the 5th min of asphyxia. On the 30th and 60th min of reoxygenation after 2.5- and 5-min asphyxia, basal adenylate cyclase activity does not differ from the initial activity. The stimulating effect of norepinephrine and NaF on enzyme activity is weakened after 5 min of asphyxia and 30 min of reoxygenation after 2.5- and 5-min asphyxia. Even short-term asphyxia affects adenylate cyclase activity and modifies the mechanisms of adrenergic signal transduction in the brain cortex in response to oxygen deficiency and probably to hypercapnia as well as during the early reoxygenation period. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 124, No. 8, pp. 131–134, August, 1997     

Temperature dependence of acetylcholine esterase activity in synaptic membranes from rat brain during hypothermia

The degree of substrate inhibition of acetylcholine esterase activity decreases in plasma synaptosome membranes isolated from the cerebral cortex of rats subjected to short-term and prolonged hypothermia at 20°C, while activation energy and breakpoint of the temperature curve in the Arrhenius coordinates remain unaffected. The observed changes are supposed to compensate the inhibitory effect of hypothermia on enzyme activity. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 129, No. 3, pp. 326–328, March, 2000     

1H-NMR imaging of fimbria fornix lesions in the rat brain

Summary Mechanical lesions of the fimbria fornix (FF) have been widely used as a model to investigate the recovery of damaged brain tissue.¹H-NMR imaging was employed to non-invasively measure changes in the brain after unilateral FF transection. Rats were subjected to NMR imaging at various times after the lesions were made. The experimental protocol included (multislice) T₂-weighted and diffusion-weighted imaging thereby allowing the construction of two-dimensional maps of the relaxation time T₂ (transverse or spin-spin relaxation time) and the apparent diffusion coefficient (ADC) of water. FF transection induced considerable changes in the status of the brain tissue at a number of different locations which were exclusively present in the affected hemisphere. At 1 day post-lesion the region of the lateral ventricle and hippocampus started to display pronounced changes in that T₂- and diffusion-weighted images showed a hyperintensity and a hypointensity, respectively. These effects were maximal around day 2 to 4 whereafter a slow recovery towards the control situation was observed. Immediately after transection the FF lesion itself could be visualized. These early images pointed to an aspecific disruption of the tissue due to the mechanical intervention. Interestingly, however, from day 2 post-lesion a number of changes became evident in this region which seemed to be localized to specific structures, including the ventricle and hippocampus. After one month the presumably ventricular effect dominated and was predominantly localized to the anterior side of the FF lesion. These findings are indicative of pronounced changes in the status of water (e.g., in its distribution between extra- and intracellular compartments) at a number of locations distant from the site of FF transection. The mechanism by which these changes are brought about and the origin of their time-dependence remain to be elucidated.This research was carried out at the Netherlandsin vivo NMR facility at the Bijvoet Center for Biomolecular Research (Utrecht University) which is supported by the Netherlands Organization for Scientific Research (NWO).Supported by grants from the Netherlands Organization for Scientific Research (NWO).     

Relationship between litter size and the development of the rat brain during the suckling period

The brain of 23-day-old rats raised in small, large, and control litters is studied. In large litters, body weight is significantly lower and the relative mass of the brain is higher than in controls. In small litters, body weight of males and females is considerably higher, while the relative mass of the brain is lower; in females, the absolute mass of the brain and of the left hemisphere is significantly higher. In rats of both sexes from small litters the weight of body, brain, and hemisphere is higher than in rats from large litters. In addition, in males from small litters the neurons of layer V are larger. Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 121, No. 5, pp. 582–584, May, 1996     

Activity of antioxidant enzymes in the limbic reticular structures of rat brain after short-term immobilization

Translated fromByulleten' Eksperimental'noi Biologii i Meditsiny, Vol. 115, N ^o 6, pp. 612–614, June, 1993     

Stimulatory role of calcium in rapid eye movement sleep deprivation-induced noradrenaline-mediated increase in Na-K-ATPase activity in rat brain

Rapid eye movement (REM) sleep deprivation elevates noradrenaline level, which upon acting on alpha1-adrenoceptors increases Na-K-ATPase activity; however, the detailed intracellular mechanism of action was unknown. Since membrane integrity is crucial for maintaining Na-K-ATPase activity as well as ionic exchange and noradrenaline affects membrane lipid-peroxidation, we proposed that the deprivation might modulate membrane lipid-peroxidation, which would modulate intracellular ionic concentration and thereby increase Na-K-ATPase activity. Hence, in this in vivo and in vitro study, rats were deprived of REM sleep for 4 days by the flowerpot method and suitable control experiments were conducted. The deprivation simultaneously decreased membrane lipid-peroxidation as well as increased Na-K-ATPase activity by its dephosphorylation and all the effects were induced by noradrenaline. Further, in vitro experiments showed that hydrogen peroxide (H(2)O(2))-induced enhanced lipid-peroxidation increased synaptosomal calcium (Ca(2+))-influx, which was also prevented by noradrenaline and nifidipine, an L-type Ca(2+)-channel blocker. Additionally, both nifidipine and cyclopiazonic acid, which have opposite effects on intracellular Ca(2+)-concentration, prevented deprivation induced increased Na-K-ATPase activity. We propose that REM sleep deprivation elevates noradrenaline level in the brain that acting on alpha1-adrenoceptor simultaneously reduces membrane lipid-peroxidation but activates phospholipase-C, resulting in closure of L-type Ca(2+)-channel and releasing membrane bound Ca(2+); the latter then dephosphorylates Na-K-ATPase, the active form, causing its increased activity.     

Effect of neonatal hypothyroidism on Ca-ATPase activity in the rat brain

Effect of neonatal hypothyroidism on kinetic properties of Ca²⁺-ATPase from rat brain synaptic plasma membranes and microsomes were examined. Neonatal hypothyroidism resulted in significant decrease in the enzyme activity in both the membrane systems. The synaptic membranes in control group displayed presence of one kinetic component whereas a low affinity component became evident in the hypothyroid group. In the microsomes, both control as well as hypothyroid groups showed presence of two kinetic components with the latter group showing two-fold increase in the K_m. The Ca²⁺ binding characteristics were generally unaltered in the enzyme from both the membrane systems. Our results suggest that impairment in the Ca²⁺-ATPase activity together with altered kinetic properties could be one of the underlying biochemical mechanisms leading to CNS dysfunction as a consequence of thyroid hormone deprivation during critical stages of brain development.