Effect of Platinum Nanoparticles on the Structure of Protein Molecules and Regulation of the Tone of Brain Vessels in Experimental Animals.

The effects of platinum nanoparticles on the morphological structures of the solid phase of blood serum and the tone of cerebral microvessels as indicators of the dynamics of homeostasis were studied on outbred albino male rats (n=40) weighing 300-350 g. Platinum nanoparticles were injected to experimental animals in 1 ml of physiological saline. For systemic BP measurements and blood sampling, the femoral artery was isolated and catheterized. The study of solid phase structures of blood serum was conducted by the method of cuneiform dehydration. The results showed that injection of platinum nanoparticles significantly affected the body of experimental animals.

A Marker of Cerebral Ischemia in Solid State Structures of Blood Serum.

Reversible cerebral ischemia of medium severity was reproduced in male Wistar rats by bilateral occlusion of the common carotid arteries. Solid-phase structures (anisomorphons) were obtained by marginal dehydration of the serum. Small focal isotropic defects in the serum anisomorphon texture were found in 100% cases during occlusion of the carotid arteries. Similar signs were detected in all patients with chronic cerebral ischemia, which proved specificity of this morphological marker of the disease.

Wavelet Analysis of Cerebral Microcirculation in Hypovolemic Shock.

Hypovolemic shock leads to severe cerebral ischemia and increases spectral amplitudes of cerebral blood flow oscillations in respiratory frequency range.

Blood serum structures integrated assessment of pathophysiological changes in experimental cerebral ischemia.

The purpose: The purpose. To reveal solid-phase structures of blood serum during and after experimental cerebral ischemia. Methods: Integrated estimation pathophysiological changes at brain ischemia received on solid-phase structures of blood serum (BS) at 27 rats-male Vistar in weight of 300-390 g. Reversible brain ischemia of moderate severity was reproduced imposing surgical clips on both common carotids for 15 minutes then clips removed and provided bloodstream restoration on carotids. Blood took away in Eppendorf`s test tube in volume on 1 ml before imposing clips, directly ahead of their removal and in 30 minutes after bloodstream restoration. By the Method cuneiform dehydration received BS facia (dry a film) which structures analyzed by means of stereomicroscope MZ12 firm «Leica¼. Results of researches fixed on structural parameters BS before imposing clips, after removal clips and in 30 minutes after bloodstream restoration. Results: Before ischemia the integrated picture facias BS rats had the harmonious system organisation: the radial or partially-radial arrangement of the cracks, accurately generated konkrecias that testified to normal physiological condition of experimental animals. During the period occlusions carotids there were markers of a ischemia, activation of a capillary blood-groove, inflammatory reaction and stress. Partially these signs remained at reperfusion. Conclusion: The conducted researches of structures BS on experimental animals have allowed to reveal marker structures BS similar revealed at inspection of people with an ischemia of a brain.

Effect of cerebral ischemia on redox status of plasma aminothiols.

We measured the content of reduced aminothiols (cysteine, homocysteine, and glutathione) after mechanical occlusion of the middle cerebral artery in rats. During acute period of ischemia (3 h), these parameters decreased by ~10 times. In 7 days, the content of reduced aminothiols in some animals remained low, but in the others surpassed the initial levels. These results indicate significant impairment of the redox status of the circulating aminothiol pool apparently caused by oxidative stress of the peripheral vascular endothelial occurring as a response to cerebral ischemia. Thus, the total amount of homocysteine is considered a risk factor for stroke, while its reduced fraction can reflect the post stroke state.

[Influence of hyperhomocysteinemic on the wavelet-analysis of cerebral blood flow].

The objective of this study is to assess the effect of different blockers of a vessel tone on the cerebral blood flowmotion in rats using spectral analysis based on wavelets transform of the periodic oscillations of the cerebral laser Doppler flowmetry signal. Three frequency intervals were identified (0.01-0.04 Hz, 0.04-0.126 Hz, 0.126-0.4 Hz) corresponding to endothelial, neurogenic and myogenic origins. It was increase of amplitude in endothelial interval during acute hyperhomocysteinemie. We suppose that modulation factors form the value of cerebral flow which supports on constant level during autoregulation.

Adaptation to hypoxia prevents disturbances in cerebral blood flow during neurodegenerative process.

The rats with neurodegenerative brain disorder induced by administration of a toxic fragment of beta-amyloid demonstrate weakened endothelium-dependent dilation of cerebral vessels, which attested to impaired production of endothelial NO. At the same time, toxic beta-amyloid fragment induced the formation of NO depots in the walls of cerebral vessels, which indirectly attests to NO overproduction in the brain tissue. Preadaptation to hypoxia prevented endothelial dysfunction and improved the efficiency of NO storage. Our results suggest that adaptation to hypoxia protects the brain from various changes in NO production during neurodegenerative damage.

Effect of serotonin on respiration, cerebral circulation, and blood pressure in rats.

The effects of intravenous serotonin on respiration, cerebral circulation, and blood pressure were examined in narcotized rats. Serotonin rapidly decreased local cerebral blood flow (by almost 30%) and blood pressure. Hemodynamic phenomena were accompanied by sharp changes in the respiration pattern: short-term apnea in all cases. The mechanism of this apnea was related to initial stages in blood pressure changes and had a neurogenic nature.

[Afobazole increases cerebral blood flow in rats with global brain ischemia]. / Usilenie krovosnabzheniia ishemizirovannogo mozga pod vliianiem Abofazola.

The selective anxiolytic drug afobazole administered in a dose of 5 mg/kg increased the cerebral blood flow in rats. The effect was more pronounced in rats with global reversible cerebral ischemia than in intact animals. The ischemia model was caused by occlusion of both common carotid arteries for 120 min with simultaneous reduction of the arterial pressure to 40-50 mm Hg through blood-letting. Afobazole also significantly increased the survival of rats with cerebral ischemia model caused by ligation of both common carotid arteries, which was evidence of the neuroprotector activity. Apparently, the ability of afobazole to improve the cerebral blood flow in ischemized rat brain is an important factor in realization of the neuroprotector activity.

[The effect of esafosfina on cerebral circulation in intact and ischemized rat brain]. / Vliianie preparata ezafosfina na krovosnabzhenie ishemizirovannogo mozga.

The physiological metabolite esafosfina (fructose 1,6-diphosphate) influences the cerebral circulation of intact male rats. Injected intravenously in a dose of 250 mg/kg, esafosfina improved both the blood supply to brain and the local blood flow in the parietal region. Under the conditions of global transient cerebral ischemia, the cerebrovascular effect of the drug tends to increase. Esafosfina produced dissimilar changes in the arterial blood level, which could be explained by various basic status of the test animals. The pronounced cerebrovascular activity of esafosfina plays a key role in its neuroprotector effect.

[Effect of perftoran on cerebral blood flow in the reperfusion period after global transient brain ischemia]. / Vliianie perftorana na tserebral'nyi krovotok v reperfuzionnyi period posle global'noi prekhodiashchei ishemii golovnogo mozga.

It was established, while modeling the global transient cerebral ischemia in experiments with 51 anesthetized nonlinear white rats (weight 300-330 g), that a preliminary administration of perftoran in the discussed pathology does not only improve the reperfusion process in the brain but also levels the deficits of crystalloid solutions used as blood substitutes (by the example of physiological solution). Therefore, the drug has a cytoprotective action on the vascular-system endothelium. A direct admixture of perftoran to the autoblood introduced after global transient cerebral ischemia improves essentially the reperfusion-period course in the brain versus the combination of physiological solution and autoblood.

[Comparative study of dilceren (nimodipine) on the cerebral circulation in the intact animals and animals subjected to ischemic brain damage]. / Sravnitel'noe izuchenie diltserena (nimodipina) na mozgovoe krovoobrashchenie intaktnykh zhivotnykh i posle global'nogo ishemicheskogo porazheniia mozga.

The influence of the calcium entry blocker dilceren (nimodipine) on the local and regional circulation was studied in rats and cats. In the majority of experiments on intact animals, dilceren increased the local and regional blood flow. However, in some cases, the circulation decreased or remained unchanged, which was accompanied by pronounced hypotension. Administered after global brain ischemia, dilceren improved the cerebral hemodynamics in all experiments.

Possibility of linear dependence between vascular wall tension and blood flow in precortical arterioles.

Intravital microscopy was used to determine the diameter and length of pial cortical arterioles in rat brain. Mathematical model yielded a formula showing that regulation of arteriolar wall tension results in autoregulation of the blood flow.

[The microcirculation and the succinate and NADH dehydrogenase activities of the brain in neurotic disorders of the higher nervous activity in white rats]. / Mikrotsirkuliatsiia i aktivnost' degidrogenaz SDG i NADH-DG mozga pri nevroticheskikh narusheniiakh vysshei nervnoi deiatel'nosti u belykh krys.

A correlation was made between microcirculation and energy metabolism in the brain of 50 neurotized rats. Neurotic disorders were defined by characteristics of conditioning, arterial pressure, breathing rate and heart rate. In vivo biomicroscopy revealed modification of the state of blood vessels at rest and inverted reaction of brain pial vessels of neurotized rats to bilateral occlusion of common carotid arteries. Ratio of activities of respiratory cycle enzymes (succinate and NADH-dehydrogenases) was indicative of hypoxic state of the animals under study.