[Interhemisphere asymmetry of the CSF dynamics and biomechanical properties of the skull].

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.

[Biomechanical properties of the human cranium: aging aspects].

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.

[Slow-wave fluctuations in craniosacral space: hemo-liquorodynamic conception of origin].

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.

[Age-related characteristics of relationships between brain blood flow, liquor dynamics and biomechanical properties of human cranium].

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.

[Derivatives of N-amidinoproline and their use in conventional and solid phase peptide synthesis].

N-Amidinoproline, a hybrid structure modeling key features of the Arg-Pro sequence, was synthesized. The activation of carboxyl group of free N-amidinoproline was found to result in the formation of a cyclic side product, whose structure was confirmed by ESI MS, 1H NMR, and 13C NMR spectra. The preparation of N-(mesitylenesulfonylamidino)-L-proline using the mesitylenesulfonyl derivative of 2-methylisourea was demonstrated to be accompanied by partial racemization.

[Dynamics of local cerebral blood flow in different somatosensory cortical layers during whisker stimulation in rats].

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.

[The role of the CSF dynamic component in forming the periodic fluctuations in the electric impedance of the head].

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.

[Cerebral blood flow and cerebrovascular reactivity in the early postnatal ontogeny of rats].

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.

[A comparison of the measurements of local cerebral blood flow by hydrogen clearance with hydrogen inhalation and by its electrochemical generation in brain tissue].

The goal of the present investigation was to compare data received by modifications of H2-clearance method with inhalation (H2-Inh) and electrochemical generation in brain tissue (H2-Gen) of H2 from the same recording electrodes in acute experiments (urethane 1g/kgip) with Wistar rats (n = 39). Block of three or four Pt electrochemically sharpened electrodes to tip diameters of 20-40 mu, 0.3-0.

[Combinations of methods for the monitoring of the cerebral microcirculation].

Any single method for measuring changes in local cerebral blood flow (LCBF) or blood vessels during physiological stimuli has individual strengths and deficiencies. The coupling of multiple methods based on different physical principles permits simultaneous measurements and tests of interrelated cerebrovascular changes and mechanisms. The present paper describes combined recordings of LCBF by H2 clearance with inhalation (H2Cl-Inh) and with steady electrochemical generation (H2Cl-Gen), by laser Doppler flowmetry (LDF) and by dimensional changes in surface vessels with videomicroscopy through acute cranial windows in rats anesthetized with urethane 1g/kg or urethane (0.

[The characteristics of the correlation of the functional activity, blood supply and structural organization in the sensory-deprived cerebral cortex in rats].

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.

[The functional tasks of the activity of the mechanism regulating the cerebral circulation].

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.

[The effect on the cerebral microcirculation of in vivo stains used in biomicroscopy].

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.

[The effect of local electrostimulation of nerve tissue on its blood supply indices in extreme brain states].

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.

[The reactivity of the major vessels of the human brain based on the data of transcranial dopplerography].

Clinico-physiological studies of 426 healthy subjects revealed normal parameters of the blood flow linear velocity along the extra- and intracranial portions of major cerebral vessels as determined by means of transcranial dopplerography. Normal parameters of the systolic-diastolic coefficient, the reactivity of major vessels and their pial draining network were studied in respect to their responses to functional loads of physical and chemical character which enabled one to determine functional possibilities of the cerebral circulation system. The ability of the dopplerographic technique was assessed in respect to studying of separate control mechanisms of the brain circulation system.

[The cerebrovascular effects of motion sickness].

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.

[The structuro-functional modulus of the microcirculatory network of the cerebral cortex in rats].

Complex investigation carried out in rats with the aid of polarographic microelectrodes revealed a mosaic distribution of blood supply within a small volume of nerve tissue in resting. The activation of cortical neurons was accompanied by local functional hyperemia and increased level of oxygen available. The hyperemia spread over a 200-300 mu area corresponding to the sides of neuronal columns.