[Unformed conglomerate debilitating jejunal fistulas and their two-stage surgical treatment via posterolateral laparotomy]. / Nesformirovannye konglomeratnye istoshchayushchie toshchekishechnye svishchi i ikh dvukhetapnoe khirurgicheskoe lechenie iz zadnebokovogo laparotomnogo dostupa.

OBJECTIVE: To create a method of two-stage repair of high unformed conglomerate delimited debilitating jejunal fistulas via posterolateral laparotomy with low risk of surgical complications. MATERIAL AND METHODS: Methodology and treatment outcomes were analyzed in 37 patients with unformed conglomerate high debilitating delimited jejunal fistulas. Of these, 22 patients underwent one-stage treatment through 2 converging incisions and/or two-stage treatment through anterolateral access. They made up a control group. Fifteen patients in the main group underwent two-stage treatment via posterolateral left-sided laparotomy with unilateral disconnection of jejunum with fistula. In most patients of both groups, fistulas complicated surgery for acute adhesive intestinal obstruction. Topography of adhesions that caused acute intestinal obstruction in both groups was studied in 172 other patients. Identical jejunal fistulas and two different surgical approaches made it possible to consider our groups representative. RESULTS: Two-stage treatment via posterolateral left-sided laparotomy reduced mortality from 63.6±10.2% to 20.0±10.3% (t=11.8; p<0.001). This approach simplified intraoperative diagnostics that became more informative. Posterolateral access increased the quality of anastomosis and safety of viscerolysis. CONCLUSION: A new two-stage approach with posterolateral left-sided laparotomy allowed atraumatic imposing of inter-intestinal anastomosis with proximal disconnection of jejunal fistula. This exclusion turns the fistula into analogue of the definitive Meidl's jejunostomy, unloads the intestinal anastomosis and increases the quality of suture. New strategy reduced the risk of complications and mortality.

[Role of the motor cortex in the control of axial and proximal muscles in learning].

Involvement of the motor cortex in the control of the shoulder and the scapula muscles was studied during acquisition of the novel head-forelimb coordination in dogs. The dogs were trained to raise the forelimb fixed to the lever in order to lift a food-containing cup and keep it elevated during eating with the head tilted down to the feeder. At the early stage of learning, the movement of raising the limb occurred with an anticipatory upward head tilt, whereas the head tilt to the feeder was associated with the lowering of the raised limb. Food consumption required a new coordination, i.e., maintaining the raised limb in a posture with the head lowered. This coordination could only be achieved by learning. This new coordination was critically dependent on the intact motor cortex. It was found that in the natural coordination, raise of the limb involved regular activation of the main flexors of shoulder, i.e., deltoid and teres major muscles, and inconstant participation of teres minor, supra- and infraspinatus, trapezius muscles. Muscles of the latter group were often active during standing but ceased their activity before limb raise. The learned limb raise with the head tilted down occurred with activation of all the mentioned muscles, and some of them changed their activity for the opposite pattern. Lesions in the motor cortex (inclusive the main part of the projection area of the "working" limb) led to a restoration of the natural head-fore- limb coordination and the innate muscle pattern of the limb raise. Thus, in the course of learning, the motor cortex rearranges the innate pattern of coordination of phylogenetically old axial and proximal muscles, which begin to work in a new manner.

Role of the motor cortex in the rearrangement of a natural movement coordination in dogs.

Chronic experiments on dogs were performed to study the activity of the shoulder muscles involved in elevating the forelimb used by the animal to lift a food-containing cup and keep it elevated during eating. At the early stage of acquisition of this operant reaction, limb-lifting occurred with an anticipatory upward head movement; lowering of the head to the feeder was associated with lowering of the lifted limb. The new coordination required for food to be obtained, i.e., maintaining the elevated limb in a posture with the head lowered, could only be achieved as a result of learning. In untrained dogs with the natural coordination, elevation of the limb occurred with activation of the deltoid and teres major muscles, teres minor being active on standing but ceasing its activity before limb elevation. During training the activity of the teres minor muscle changed to the opposite pattern. Limb elevation in the learned coordination was accompanied by activation of all three shoulder flexors. Lesioning of the motor cortex in the projection area of the "working" limb, but not in other areas, led to impairments of the acquired coordination and a new pattern of shoulder muscle activity. These data led to the conclusion that rearrangement of the initial coordination was linked with the formation of a new means of elevating the limb in which the muscle pattern was supported by the motor cortex.

[The role of the motor cortex in rearrangement of the innate movement coordination in the dog].

In chronical experiments in dogs the pattern of shoulder muscle recruitment was examined during the forelimb flexion by which the animal lifted and held a cup of food during eating. At the early stage of the instrumental reaction learning the forelimb lifting was performed with the anticipatory deviation of the head in up direction, when the head bent down to the foodwell the lifted forelimb lowered. Simultaneous holding of the flexed forelimb and lowered head providing food reinforcement was achieved only by learning. It was found that the forelimb lifting in the innate coordination in untrained dogs was performed with activation of m. deltoideus and m. teres major, whereas m. teres minor was active whilst the dog was standing but the muscle activity was abolished before the limb lifting. In the course of learning m. teres minor activity was changed into opposite one. In the learned coordination the limb lifting was accompanied by the activation of all three shoulder flexors. The lesion of the motor cortex in the area of the "working" forelimb, but not in other areas led to disturbance of the learned coordination and the novel pattern of the shoulder muscle activity. The data obtained led to the following conclusion: the rearrangement of the innate coordination is connected with the formation of the novel way of the forelimb lifting which pattern of muscle recruitment is provided by the motor cortex.

[The effect of the pulsed radiation of a fast electron beam on the fluorescence of solutions of biological molecules]. / Vliianie impul'snogo izlucheniia puchka uskorennykh élektronov na fluorestsentsiiu rastvorov biologicheskikh molekul.

The intensity of fluorescence of amino acid and globular protein solutions, exposed to a pulsed electron beam in the presence and absence of the concurrent pulsed electromagnetic field was found to be a function of radiation dose. The observed decline in the fluorescence intensity was slightly dependent on the solution concentration and dependent on the time and dose-rate of irradiation. The effect of the concurrent pulsed radiation of the electromagnetic field was sometimes observed.

Comparison of coupling of impulse activity of cerebral cortical neurons and spatial synchronicity of the EEG.

The coherence of the EEG and the coupling of the impulse activity of neurons of the visual and sensorimotor areas of the neocortex of rabbits, recorded simultaneously from the same electrodes, were compared under chronic experimental conditions. An association was found between the presence and properties of the conjugated functioning of neurons and the coherence of the EEG at various frequencies. Greater coherence of the EEG was observed during the correlated functioning of neurons at frequencies of 3-4.5 Hz than during independent functioning. The neurons discharged in pairs, with a smaller delay between them at the highest level of EEG coherence, and a common source participating more often in their synchronization than at the lowest level of EEG coherence.

[An analysis of the dipole characteristics of the evoked potentials of the cerebral cortex]. / Analiz dipol'nykh kharakteristik vyzvannykh potentsialov kory golovnogo mozga.

Possibility is studied of application of the current dipole in uniform unlimited medium for description of the sources of the evoked potentials recorded epidurally and on the skull surface. By means of computing experiment the influence is analyzed of per-layer heterogeneity of skull and scalp conductivity on precision of the solution of the inverse problem of electroencephalography with the use of the above model. It is shown that at epidural focal recording of the potential, the application of the model is adequate, and at extracranial recording introduction of additional corrections is required. The results of the analysis are used for the description of the change of parameters values of the sources of individual primary response of the cat visual cortex to electric stimulation of the local region of the lateral geniculate body, what allows to specify the characteristics of possible sources of the primary evoked electrical activity of the cerebral cortex.

[A spectral-correlational analysis of the EEG of the neocortex in the rabbit in a state of thirst]. / Spektral'no-korreliatsionnyi analiz EEG neokorteksa krolika pri sostoianii zhazhdy.

Summate electrical activity of the rabbit neocortex during formation of drinking excitation was studied by means of mathematical analysis. It is shown that the change of the electrical activity depends on the level of drinking excitability created by various duration of water deprivation (24-48 h) and is expressed in a generalized lowering of potentials amplitude without frequency change. Spectro-correlative EEG analysis showed that lowering of spectrum power took place within the whole analyzed frequencies range. Besides, an increase took place of interconnections of the cortical electrical processes, estimated by coherence function. It may by suggested that the manifested reconstruction of spectro-correlative characteristics of the neocortical biopotentials reflects a formation of motivational excitation establishing optimal level of cortex functioning.

[A comparison of the spike train activity of the cortical neurons and of the spatial synchronization of the EEG]. / Sopostavlenie sopriazhennosti impul'satsii neironov kory golovnogo mozga i prostranstvennoi sinkhronnosti EEG.

In chronic experiments EEG coherence and conjugation of impulse activity were compared of neurones of the visual and sensorimotor areas of rabbits neocortex simultaneously recorded with the same electrodes. Connection was revealed between the presence and properties of conjugated neurones activity and EEG coherence at various frequencies. At correlated neurones activity a greater EEG coherence was observed on frequencies of 3-4,5 Hz than at the independent activity. At the highest level of the EEG coherence the neurones discharged with less delay of one after the other in pairs, and in their synchronization a common source participated more often than at the lowest level of the EEG coherence.

[Accuracy of the spatial localization of the sources of brain bioelectrical activity in a model homogeneous unrestricted environment]. / O tochnosti prostranstvennoi lokalizatsii istochnikov bioélektricheskoi aktivnosti mozga v modeli odnorodnoi neogranichennoi sredy.

The possibility is considered of use of the model of homogeneous unlimited medium (HUM) for localization of sources of brain bioelectrical activity at recording of electric potentials on its surface. It is shown that when the recording electrodes are arranged in accordance with 10-20 system, the source localization error does not exceed 10% of the head radius practically in any position of the source. A significant dependence is revealed of the source localization error on the concrete electrodes system used in experiment. It demands careful treatment of the available general recommendations on correction of the position of the source found by HUM model without consideration of the concrete arrangement of recording electrodes.

[Effect of the background activity of a network of excitatory neuron-like elements on the conduction of excitation]. / Vliianie fonovoi aktivnosti seti iz vozbuditl'nykh neironopodobnykh élementov na provedenie vozbuzhdeniia.

Calculation on a mathematical model showed that for distortion-free conduction of excitation through a net of excitatory elements (EEs) a system is necessary of optimum correlation of EEs parameters, links between them and of external influences. When these parameters are deviated from their optimum values, excitation is conducted through the net either with attenuation or with intensification (as a result of divergence and convergence of the influences of the previous layer on the following one). The background activity which is above threshold of impulse activity emergence and which is created by common effects on all EEs, prevents the revealing of the input EEs activation at the net output. Near-threshold tonic net activation facilitates excitation conduction through it. Periodic net activity facilitates excitation conduction through it only under optimum correlation of its parameters and the time of its conduction through the net. At disturbance of this condition, excitation conduction through the net is limited.

[Model of nerve net learning based on changes in the efficiency of excitatory and inhibitory synapses]. / Model' obucheniia neironnoi seti na osnove izmeneniia éffektivnosti vozbuditel'nykh i tormoznykh sinapsov.

Based on recent data on learning neurophysiology, a dynamic model of a nervous network was created, consisting in systems of locally connected excitatory and inhibitory elements and general excitatory and inhibitory systems. Interneuronal interactions were realized by means of imitation of impulse transmission of information, spatial-temporal summation of excitatory and inhibitory influences, the effect of "disinhibition" by the mechanism, imitating the depression of inhibitory elements during overexcitation and presynaptic inhibition of inhibitory systems. When learning the model, the Hebb's principle was applied, i. e. and irreversible increase of synaptic transmission after coincidence of activation of pre- and postsynaptic neurones. The processes, imitating the elaboration, extinction and recovery of conditioned reflex were studied. Some initially unforeseen effects were revealed. The universal properties of the model are being discussed.

[Blocking action of nickel, cobalt, manganese, and magnesium ions on the inward current through the potassium channel of Limnea stagnalis pond snail neurons]. / Blokiruiushchee deistvie ionov nikelia, kobal'ta, margantsa i magniia na velichinu vkhodiashchego toka cherez kal'tsievyi kanal neironov prudovika Limnea stagnalis.

The dose-inward current relationship for calcium channel blocking ions of Ni, Co, Mn and Mg was studied by means of intracellular dialysis and voltage clamp in isolated neurons from the mollusc Limnea stagnalis. For all the four ions the effect was described by the Langmuir isotherm with KMn = 0.36 +/- 0.05 m,, KNi = KCo = 0.74 +/- 0.07 mM, KMg = 18.2 +/- 5.00 mM. These bivalent cations compete with current-carrying ions for a common binding site in the channel's entrance.