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An investigation of the effects of drying and drying-rewetting cycles under vacuum conditions of 10(-2) torr at -30 degrees C on conidia of the atmospheric strain Penicillium chrysogenum from 48-77 km heights, collected by meteorological rockets found that survival and restoration of the initial physiological properties were possible through some very efficient protective cellular mechanisms. Such adaptive possibilities explain the widespread diffusion of microbial cells throughout the biosphere of our planet.

A defensive instrumental conditioned reflex (CR) successively to light flashes and to electrostimulation of the dorsal hippocampus (DH) and the caudate nucleus (CN) was developed in dogs with electrodes implanted in the brain. The contralateral of the DH, CN, the accumbent nucleus (AN) and the globus pallidus (GP) were tested for reproducibility of the instrumental movement. In a second series, the percent of evoked movements was compared with the EP arising in response to signal and test stimulation. The degree of participation of the tested structures in the motivational, signal, and executive components of the CR was elucidated. In the first series the movements were practically not reproduced. In the second series, in the presence of connections from the signal to the tested structures, they were elicited only by stimulation of the AN (15%). In the same series, given bilateral connections, movements in response to the stimulation of the basal ganglia occurred somewhat more frequently (up to 28%). The stimulation of the contralateral DH elicited movements in 75-100% of cases. When stimulation of the CN became a signal, the stimulation of the AN and the GP was accompanied in 40-100% of cases by movement. Thus, the AN participates to a minimal degree in the executive component of the CR. Participation of the basal ganglia in the signal component of the CR was greatest in the third series, which indicates that intrasystemic generalization is more effective than intersystemic.

The features of orientation reaction (OR) and the background EEG were investigated with the purpose of studying the neurophysiological mechanisms of the disturbance of voluntary attention in children aged 6.5-9 years with learning difficulties caused by delayed mental development (DMD). A decrease in the expressivity of components of the OR as compared with the norm, discovered in a situation of involuntary attention against a background of insufficiently developed cortical rhythmicity in the alpha range, was compensated for given an increase in the significance of the stimuli. These facts support the hypothesis of a deficit in regulatory corticofugal influences in children with DMD. The inadequacy of the engagement of central regions of the cortex characteristic of children with DMD in the realization of OR in a situation of directed attention can be regarded as a reflection of disturbances of the integrative activity of the brain.

The temperature microstimulation of the semicircular canal (heat bursts lasting about 2 sec with a peak amplitude of 0.5-5.0 degrees C) can be regarded as an analog of angular acceleration acting within the cavity of the given canal; the combination of temperature microstimulations targeted simultaneously on several canals can serve as a physical model of accelerated rotation having complex spatial characteristics. The recording of the activity of neurons of the vestibular nuclei of the frog (n = 278) in response to temperature microstimulation of the canals showed that 80% of the neurons have inputs from one to two canals and only 20% from three to six canals. The distribution of laterality was characterized by the predominance of ipsilateral inputs: 201 neurons (72.3%) had only ipsilateral inputs; 14 neurons (5%) had only contralateral inputs; 63 neurons (22.7%) had both inputs. The ipsilateral horizontal (67.6%) and the posterior (61.9%) were the most effective inputs; while among the contralateral, the posterior (21.2%) canals were the most effective; the least effective were the contralateral horizontal (8.6%) and the anterior (5.0%) canals. The presence of latent canal inputs (both excitatory and inhibitory) which showed up in combination with effective inputs was demonstrated.

The changes in the behavior of the garden snail during self-stimulation through electrodes chronically implanted in specific regions of the brain are described in this study. The stimulation of the mesocerebral region led to an increase in the frequency of reinforced behavior, whereas stimulation of the rostral portion of the parietal ganglia led to a decrease in the frequency of reinforced behavior. An inference is reached regarding the emotional coloration of the effects of the stimulation of these regions. The interrelationships of the neurons located in the mesocerebrum and the parietal ganglia were studied in neurophysiologic experiments. It was found that the activation of the cells of the mesocerebrum inhibits the spontaneous activity of the serotoninergic cells of the pedal ganglia which sensitize the defensive reactions of the snail, and simultaneosly attenuate the sensory input of the command neurons of defensive behavior, which leads to the effective inhibition of the defensive reactions that is necessary during the activation of sexual behavior.

The features of the formation of conditioned alimentary reflexes in response to the stimulation of the basolateral division of the amygdaloid complex with an electrical current at a frequency of 50 pulses per second were studied in five dogs. The possibility of the development of differential inhibition in response to unreinforced stimulation of the same structures of the amygdaloid complex with a current at a frequency of 5 pulses per second was demonstrated. The rate of formation of positive and inhibitory conditioned reflex reactions, their quantitative characteristics, and the depth of differential inhibition in response to stimulation of the amygdaloid complex is greater than those found with the use of acoustic stimuli in the same dogs. Comparison of the rate and dynamics of the process of conditioning of two structures belonging to different levels of nervous integration, namely, the limbic (the amygdaloid complex) and the striatal (the caudate nucleus), carried out under the same experimental conditions, indicates that activation of the nervous elements of the limbic formation acquires signal significance significantly more rapidly than in the case of the caudate nucleus.

The frequency spectra of the electrograms of the dorsal hippocampus with intraventricular administration of GABA, muscimol, baclofen, bicuculline, and picrotoxin, were studied in chronic experiments on 24 awake freely-moving rats. The data obtained are in accord with the existing notion regarding the interactions of agonists and antagonists with GABA receptors. The possibility of their participation in the formation and/or modulation of the total electrical activity of the hippocampus is discussed.

The changes in the electrograms of the visual cortex of awake animals under the influence of light stimulation in conditions of a pharmacological effect on the monoamine (MA) systems of the brain were investigated in experiments on 8 rabbits and 12 rats. The following was found following the administration of MA precursors (5-hydroxytryptophan and d,l-dihydroxyphenylalanine): a) a decrease in the amplitude of the averaged evoked potentials in response to rhythmical light stimuli (1-20 pulses/sec); b) intensification of rapid (15-25 Hz) oscillations in the spontaneous electrical activity of the cortex, as well as attenuation and modification of the effects of the blocker of MA synthesis, a-methyl-dihydroxyphenylalanine. A potentiation of the MA precursors was observed with light stimulation in the frequency spectra of the electrocorticograms. The specific characteristics of the action of the catecholamine precursor were manifested in the same conditions in the form of an intensification of the power of the 5-7 Hz rhythms, and an attenuation of the power of the 2-3 Hz rhythms.

New data on the significance of mediator and peptidergic systems of the striatal level in the organization of alimentary conditioned reflexes are presented in this report. The role of acetylcholine-, dopamine-, GABA-and P-ergic systems of the caudate nucleus and the amygdala in the realization of positive and negative conditioned reflexes was investigated. The experiments were carried out on dogs with chemotrodes and microelectrodes implanted in subcortical structures. The results of the experiments with microinjections of the relevant substances into individual subcortical structures showed that activation of the same mediator system in various structures may lead to both unidirectional and multidirectional behavioral effects. On the other hand, the activation of various subcortical mediator systems can lead to identical changes in conditioned reflex activity. The effect of the administration of activators or blockers of a subcortical mediator system depends in many ways on the functional state of the nervous system at the moment of administration and on the localization of the microinjection. It is difficult to predict beforehand the role of various subcortical structures in the organization of integrated behavioral acts. The question of the necessity of studying mediator and peptidergic systems of each subcortical structure in order to understand their significance in the mechanisms of the conditioned reflex is raised.

It has been demonstrated that a gradual spontaneous recovery of a previously unreproducible memory trace and the prevention of the antiamnesic effect of the blockade of the GABAA receptor, but not of the blockade of the benzodiazepine receptor or the chloride channel, take place with the development of amnesia against the background of the activation of the GABAB receptor by baclofen. The "neurochemical set" created by the activation of the GABAA receptor by muscimol in a dose of 1 mg/kg prevents the antiamnesic effect of the blockade of any component of the benzodiazepine-GABA-ionophore complex, while at a dose of muscimol of 0.5 mg/kg, the retrieval of the amnestic trace takes place only by blockade of the benzodiazepine receptor. Thus, the development of amnesia is determined by the functional state of inhibitory GABAergic systems of the brain, which governs the subsequent correction of the amnestic memory trace.

The activity of neurons of the motor cortex with simultaneous application to them of acetylcholine was recorded in awake rabbits in the process of the development of a conditioned defense reflex. The conditioned reflex changes were found primarily in cholinosensitive neurons. It was shown that iontophoretic application of the mediator promotes the establishment of the conditioned neuronal responses and leads to an increase in their magnitude as compared with reactions recorded in the absence of acetylcholine. It is hypothesized that the influence of acetylcholine on the conditioned reflex cellular process is accomplished through an effect on the state of excitability of the cortical neurons.

A temporal analysis of changes in the response of the pyramidal tract using a model of prolonged potentiation revealed the substantial role of the mechanism of the heightening of total excitability of the cell at the initial stage of the formation of trace processes (an analog of the "dominant") which apparently promote the greater strengthening of the underlying mechanism of the CR, namely, the increase in the efficiency of synaptic associations. In the development of a CR in response to the stimulation of two points of the cortex, the increase in cell excitability was more marked in those experiments in which reinforcement was supplemented by the stimulation of the lateral hypothalamus, stimulation eliciting an alimentary reaction. These data make it possible to consider membrane plasticity as a cortical mechanism of the motivational component of reinforcement, a mechanism determining the dominant properties of the stage of generalization of the CR.

On 36,536 abdominal operations, in 36 patients (0.1%) there was necessary to perform a relaparotomy due to intraabdominal hemorrhage, of whom in 28 patients this complication arised after emergency surgical interventions, while in 8 cases after elective surgery. The cause of bleeding in 26 patients were technical mistakes during the first intervention, in two the overdosage of anticoagulants, in other two a fibrinolysis, and in one patient haemophilia. In 5 patients the origin of the hemorrhage could not be verified at relaparotomy. Clinical picture of an intraabdominal bleeding depended on its acuity and extent; in 18 patients the massive bleeding manifested suddenly or by progressive development of heart failure. In 7 patients slow evolution of the blood loss manifested with anemia and intestinal paresis. Hemoperitoneum arised in 6 patients, but without anemia, and in the other five remaining patients, a circuscripted intraabdominal hematoma was formed. In 8 patients laparocentesis was diagnostically successful. (The re-laparotomy was lifesaving for 26 patients). 12 patients died. The authors believe that well knowning of parameters of central hemodynamics, together with prolonged paresis of the gut, hyperthermia and hyperleucocytosis it is possible to recognize the predominant signs of acute postoperative hemorrhage.

A simple titrimetric method for the determination of thiol and disulphide groups in biological samples with p-diethylaminophenylmercuric acetate as titrant, is suggested. Milligram amounts of cysteine (1-25 mg) are determined with a relative standard error not higher than 1%. The lowest detenninable amount of cysteine is 0.1 mg (relative standard deviation 3%). The accuracy and the sensitivity are the same as in amperometric titration with mercuric chloride. The method has been successfully used for the determination of thiol groups in various biological samples.