Было проведено исследование церебральной гемодинамики у 65 больных с тяжелой ЧМТ (24 женщины и 41 мужчина, средний возраст 41,1 года). Всем больным была проведена многократная ТКУЗДГ для выявления количественных характеристик изменяющегося мозгового кровотока, а для визуализации морфологических изменений были проведены компьютерная (КТ), магнитно-резонансная (МРТ) томография и ангиографическое (АГ) исследование. Проведенные исследования мозгового кровотока у больных с тяжелой черепно-мозговой травмой выявили характерную картину последовательно сменяющих друг друга процессов снижения-гипоперфузии, последующего увеличения скорости кровотока-гиперемии и развития церебрального артериального вазоспазма. По характеру кровотока в вертебро-базилярном бассейне также можно прогнозировать исходы тяжелой ЧМТ.

This investigation shows that both intracranial liquor circulation and skull biomechanical properties evaluated by its pliability (compliance) to intracranial pressure are characterised by marked interhemisphere asymmetry. The interhemisphere differences of cerebrospinal fluid mobility were evaluated by means of asymmetry coefficient (right/left ratio of liquor mobility) which was found to be 1.25-1.45 in healthy middle-age persons. For the skull pliability (compliance) the coefficient of hemispheric asymmetry was 0.75-0.95. These two hemisphere asymmetry coefficients are characterized by reciprocal relationships. These coefficients demonstrated no dominancy related to right/left hemisphere as well as no correlation with neurophysiological parameter. Functional tests (apnoea, hyperventilation, Stookey test) gave rise to significant changes of these coefficient values. At ageing, the magnitudes of these coefficients decreased. The spectral analysis of pulse waves of dopplerogram and rheoencephalogram reveals hemisphere asymmetry, too. It should be suggested that the interhemisphere asymmetry of the CSF dynamics and skull biomechanical properties is a special mechanism which contributes in the process of circulatory-metabolic support of brain activity.

In the paper, the mechanism of forming of rhythmic slow-wave fluctuations in craniospinal cavity was investigated. In five young healthy persons, at rest and under voluntary respiration arrest test, the bioimpedansograms of head and lumbosacral part of vertebral column were synchronously registered as these recordings reflect the changes of relationships between blood/CSF volumes in cranial and lumbosacral regions, respectively. The recordings were subjected to frequency and spectral computer analysis (PC Macintosh G-4, Chart 5.2. software). The rapid (pulsatile) as well as slow and counter-directed waves (frequency 6-10 cycles/min) of these processes were revealed in cranial and lumbosacral regions. The data obtained suggest the CSF dynamic concept of origin of the craniosacral rhythm. The pulse and slow-frequency oscillations of the cerebral vessels tone initiate corresponding intracranial pressure waves, and the latter are the motivating forces for to-and-fro CSF shifts in caudal direction. This mechanism is accompanied by tonic contractions of lumbar muscles and sacrum movements, and it is manually perceptible as a craniosacral rhythm.

Biomechanical properties of the human skull affect its dynamic tensility (pliability, compliance) by changes of intracranial volume and pressure (deltaV/deltaP). The goal of this study is to substantiate a possibility of noninvasive and dynamic evaluation of cranial compliance. The transcranial dopplerogram of middle cerebral artery and hemispheric bioimpedance were synchronously recorded, which represent information about pulsative changes of intracranial pressure and volume, respectively. The parameters were recorded at rest and during adequate hemo- and liquorodynamic tests in different age groups--20-30, 40-50, and 70-85 years. As compared with the young group, a decrease of the cranial compliance in the intermediate age group was revealed due to an observed increase if rigidity of skull bones and ligaments, which indicates a decrease of stability of the intracranial circulatory system. However, in the group of 70-85 years the compliance rose again due to an enlargement of intracranial liquor spaces and facilitation of liquor circulation inside the intracranial cavity; this can be suggested to be a compensatory mechanism for supporting the adequate brain circulatory-metabolic state.

The peculiarities of relationships between changes of cerebral blood flow, intracranial liquor dynamics and skull biomechanics in humans were studied in an age aspect. For this aim, a non-invasive method was proposed based on concomitant registration of rheoencephalogram and transcranial dopplerogram and evaluation of relationships between intracranial volume and pulse pressure changes (P-V index). The data obtained were analyzed by pattern-phase computer processing and compared with the blood flow parameters. The investigation was carried out on healthy volunteers of 18-25, 40-50 and 65-75 years of age. It was shown that circulatory-metabolic supplying of human brain was supported by such factors as volume brain blood flow, intracranial liquor dynamics in cooperation with skull biomechanics. The cerebral blood flow decrease at aging could be compensated by increase of the reserve-compensatory abilities of the system of cranial-spinal liquor dynamics.

Whisker stimulation in rats was found to increase the local cerebral blood flow (lCBF), its SD and to damp slow oscillations. It was established that lCBF drops slightly within a few seconds after the stimulus onset. The data obtained suggest that lCBF evoked sensory stimulation changes are distinctly localized in different layers of the somatosensory cortex.

In patients with partial craniospinal blocks, the impedance responses to certain functional tests were by 20-30% less obvious. Osteopathic procedures normalised the impedance fluctuations. The data obtained suggest that the CSF dynamics plays an important role in genesis and changes of the head impedance.

The development of cortical cerebral blood flow (CBF) and cerebrovascular reactivity (CVR) were studied in Wistar rats during early postnatal ontogenesis, in groups aged 2-5, 6-8, 9-11, 12-15, 16-18 and 19-25 days. CBF was measured polarographically using inhaled hydrogen clearance method, with platinum electrodes inserted into parietal cortex. At the mentioned age periods, CBF and its percentage of adult level averaged as 38 (21%), 81 (45%), 142 (78%), 85 (47%), 110 (61%), and 118 (65%) ml/100 g/min, respectively. Hence, during the early postnatal ontogenesis CBF increased gradually, however, it did not reach the adult level up to the end of the first month. CBF peak at 9-11 days period is suggested as a result of sharp rise of the brain vessels growth. CVR was assessed as the percentage of CBF increase after standardized 5% CO2 inhalation test. At the above age periods, CVR was found to bi 26, 33, 36, 41, 44 and 31% respectively, and was similar to adult rat CVR of 36%. The conclusion was drawn that regulatory mechanisms of adequate responses of brain vasculature to chemical metabolic factors are well developed already at the very beginning of postnatal life.

The feature of correlation between functional activity of the brain tissue and structural-functional characteristics of the vascular system after sensory deprivation by the removal of whiskers in newborn animals were studied in nembutal-anaesthetized rats in comparison to the animals under d-tubocurarine with local anesthesia. It has been shown that there are major changes of EP parameters and ECoG in the sensory-deprived brain area and diminution of brain cortex thickness. Changes in the vascular system are mainly structural, what are revealed as disorganization in angioarchitecture of radial arteries. At the same time, differences in the blood circulation intensity are found in d-tubocurarine animals only. The largest volume of the local blood circulation is observed in intact hemisphere of sensory-deprived animal. Thus, it can be concluded that sensory-deprived model is the alternative to the ischemia model. This model can be used in studies of physiology of brain blood circulation, and the "structure-function" correlation, in particular.

Vasoactive properties of semi-colloidal acid stains of the Evan blue and tripane blue, were revealed in rabbits and rats. The microphoto-technique revealed a dose-depending vasodilating effect of the stains. The response of the arteries had sometimes a biphasic character: constriction--dilation. I. v. administration of the stains induced a dose-dependent significant reduction of local blood flow in the cortex, subcortical white substance and other parts of the brain, of total cerebral blood flow in the venous sinus; a drop of systemic arterial pressure in normo- and hypertensive animals; a change in cerebral bioelectrical activity with increasing theta-waves, appearance of spikes and polyspikes in the EEG. Acting upon the formation of vascular tonus, these stains can interfere with the mechanisms of regulation of cerebral blood flow.

The specifics of local blood flow (LBF) was studied in the areas of electrical stimulation. The occurring changes are determined primarily by the functional state of neural tissue in the stimulation area as well as in the whole brain. The cortex develops an insrement of the LBF after stimulation by the 4th-5th day whereas no such tendency was found in the white matter.

Modern experimental and clinical data suggest that physiological mechanism, responsible for maintaining adequate brain blood supply under different conditions has a complex functional task, which besides sufficient metabolic transport to brain tissue, consists in supporting of water balance of brain tissue and evacuation of wastes. These functions realize by synergistic acting of several control links--neurogenic, metabolic, myogenic and humoral, every one of them has its own channel of input information and feedback. Physiological reactions of cerebrovascular system to adequate sensory activation have a task, first of all, to support of metabolic supply of nerve tissue. Therefore, after the beginning of sensory activation, oxygen availability in brain tissue is significantly increase, but at the same time some changes of hydratation nerve tissue is taking place. The last is possible to observe by analysis of changes in amplitude and configuration of electrical impedance pulsations, recording from brain implanted electrodes. These changes of hydratation of nerve tissue is observing during short time period and then is compensating. During during neuronal activation the concentration of wastes in brain tissue is slightly increase, which reflects in changes of brain tissue pH and pCO2. However, in situations, closed to extreme ones, a some hierarchic relationships between particular functional tasks of cerebrovascular control mechanism are observed. (1) Under arterial hypertension, when it is impossible to maintain at the same time both metabolic supply of brain tissue and to support water balance of nerve tissue, experimental and clinical data indicates, that the leader place take processes, responsible for the hydration of nerve tissue. So, the same decrease of cerebral blood flow during arterial hypertension indicates, that the action of control mechanism of cerebral circulatory system directed to minimization of a risk of developing of brain edema. (2) In cases of arterial hypotension, which accompanying by chronic cerebral circulatory insufficiency, the main functional task of cerebrovascular control mechanism becomes to direct to evacuation of wastes, because they are slowly collecting in brain tissue, although the metabolic supply of brain tissue is often in sufficient limits. In such conditions vasodilator drugs with a short time period of action (30-40 min.) have a comparative long (3-5 hours) positive effect for patients. During time period of increased brain blood flow, washing out of brain tissue from wastes is taking place. Generally, the first of mentioned processes is forming the left and the second--right parts of the curve, which represents the autoregulator phenomenon.(ABSTRACT TRUNCATED AT 400 WORDS)

In rabbits with implanted electrodes, a diminished reactivity of vascular vessels to functional tests of physical and chemical nature was revealed although the level of cerebral blood flow generally increased. This suggests a reduction of compensatory capacity of the brain circulation system which can result in a change of the brain tissue water balance under the effects leading to an alteration of cerebral outflow and sometimes accompanying seasickness. This was corroborated by the evidence on a change in cerebral tissue impedance under the combined effect of antiorthostatism and seasickness, as well as by the evidence on dynamics of cerebral rheogram pulse waves.