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A brief increase in the ascorbic acid concentration in the rat cerebral cortex after intraventricular bilateral injection of 20 μl of a 0.1% or 1% ascorbic acid solution and also intracisternal injection of 20 μl of a 0.5% solution results in a prolonged (not less than 21 days) ultrastructural reorganization in the nucleus and cytoplasm of the cortical neurons: the amount of lysosomes, polysomes, vesicles of the Golgi complex, and subsurface cisterns increases, this demonstrating an increasing RNA and protein synthesis, catabolic processes, and neuronal-glial interaction. Changes in the ultrastructure of the synaptic terminals, such as disintegrating mitochondria, formation of myelin-like bodies, and, in addition, after interstitial injection, protrusions into the adjacent dendrite, demonstrate that synapses are one of the sites where excess ascorbic acid affects the CNS. Over a long period, 3 and 6 months after injection, the changes mentioned are not observed but in the glial processes one can observe vacuoles containing degenerating elements.

Objectives. To study the parameters of vestibular evoked myogenic potentials in patients with various types of vertigo. Materials and methods. A total 77 patients (35 men, 42 women) aged 43.7 ± 12.5 years with vestibular vertigo and postural instability were studied. Surface electrode myography was used to record the activity of the sternocleidomastoid muscle arising in response to sound stimulation of the ipsilateral ear. Results and discussion. As compared with controls, patients with signs of impairment to the central compartment of the vestibular analyzer showed a tendency to an increase in the latent period of the N2 wave and a significant reduction in the amplitude of the P1–N2 complex on both sides (p < 0.005), without any significant change in the coefficient of asymmetry. Patients with signs of damage to the peripheral compartment of the vestibular analyzer showed signifi cant increases in the latent period of P1 as compared with healthy subjects (p < 0.005). In addition, there was a statistically signifi cant (p = 0.0007) increase in the coefficient of asymmetry of latent period P1. Patients with postural instability showed no significant differences in P2 and N2 latencies as compared with controls. Conclusions. The study results showed that patients with vertigo of both peripheral and central genesis have impairments to the formation of the vestibulospinal reflex at different levels of the vestibular analyzer.

We report here data on a number of systematically recorded phasic EEG phenomena during the sleep–waking cycle, along with data on the heterogeneity of the EEG stages of sleep forming sequential sleep macrocycles in humans. These transient EEG changes quite often showed a tendency to periodicity, especially at the initial stages of sleep and in transitional states; characteristic sleep microcycles were observed. An attempt to identify the microstructures of EEG sleep stages during the sleep–waking cycle was made by identifying seven clusters reflecting changes in the biopotential field of the brain represented in n-dimensional factorial space. Most sleep stages were found to consist of three or four clusters, though some sleep periods (especially Loomis stage B and 1REM) were more homogeneous in structure. It is suggested that this heterogeneity of the microstructure of the spatial organization of oscillations in brain biopotentials in particular sleep stages reflects the dynamics of neurophysiological processes, promoting more effective performance of the repair and homeostatic functions of sleep.

Administration of pituitrin, vasopressin, and oxytocin to rats during spontaneous micturition increases diuresis and sodium excretion by reducing tubular reabsorption. In adrenalectomized rats these preparations have no diuretic effect and increased sodium excretion is observed only after administration of vasopressin. After hypophysectomy the diuretic effect of the preparations disappears but they still increase sodium excretion. It is postulated that the diuretic effect of the neurohypophyseal hormones is connected with activation of the pituitary-adrenal system, whereas some additional mechanism is involved in their effect on sodium excretion.

The aim of this study was to assess the neuropsychological status of patients and their P300 cognitive evoked potentials and to attempt to evaluate the clinical significance of cerebral atrophy in multiple sclerosis (MS). Neuropsychological studies were performed in 109 patients with MS. Cognitive functions were evaluated using the mini-mental state examination (MMSE), the frontal assessment battery (FAB), the A. R. Luriya method, and P300 cognitive evoked potentials; MRI data from 71 patients were also analyzed. The results obtained from these studies led to the conclusion that changes in status and cognitive function, disease activity, and the severity of cerebral atrophy are correlated.