Neurobiological studies of gamma-band bioelectrical activity in humans

The modem literature data were observed, which dedicated to the study of neurobiological studies of gamma-rhythm mechanisms, providing the cognitive functions in hymans: state of readiness and attention, providing of sensory indentification, perception and memorizations, decision-making, management of psychomotor response, emotional and semantic processing of an information. It was shown that synchronous gamma-activity is at integrative activity, which in deteriorated in pathology of thinking. Literature data were analysed concerning ot the changes of gamma-activity (spontaneous, evoked, provoked by photostimulation etc.) in a number of neuropsychiatric disorders: epilepsy, schizophrenia, Alzheimer's disease, attention deficit hyperactivity disorder, stroke etc. as compared with norm. The data observed testify to high significance of gamma-activity in the brain functioning.     

In vitro study of antimicrobial activity of lactoferrins from various sources

Comparative antimicrobial activity of lactoferrins from various sources (native lactoferrin from Laprot, human hololactoferrin, recombinant human lactoferrin isolated from the cultural medium of permissive cell culture transfected using pseudoadenovirus nanostructure with the human lactoferrin gene, and native bovine lactoferrin) was studied to prove the possibility of their use for development of antimicrobial drugs. It was shown that all the substances were active against the Bacillus standard strains. The antibacterial activity was almost independent of the degree of saturation the lactoferrin molecules with Fe3+. The native human lactoferrin was more active than hololactoferrin against Candida when evaluated by the minimum inhibitory concentration (MIC). Fe(3+)-Non aturated recombinant human lactoferrin demonstrated the antimicrobial activity (by MIC) similar to that of the native human lactoferrin. The results showed that native and recombinant human lactoferrins might be used for the development of intravenous and intracavitary dosage forms, while the native bovine lactoferrin could be useful in development of oral drugs.     

Comparison of binaural release from forward masking in animals and humans. Electrophysiologic study

The EPs of the inferior colliculus and auditory cortex in anaesthetized guinea pigs and the long latency auditory EPs in alert humans were studied. The stimuli consisted of binaurally presented pairs of clicks used as a masker, and the probe, with a variable time delay between them. The greatest relative differences between out-of-phase and in-phase probe responses were observed at the beginning of the recovery course. They averaged as 1.6, 1.5 and 1.4 for the responses of the inferior colliculus, auditory cortex and long latency potentials, resp., at the stimuli intensities of 50-65 dB SPL, and then decreased to zero during the time course of the probe response recovery. Correlation of this parameter with the stimulus intensity was positive.     

Local disinhibition with bicuculline does not break the trained relationship between afferent input and efferent output in cat motor cortex

Neurons of the cat motor cortex related to the lifting-withdrawal phase of forepaw placing reaction are preferentially activated by tactile stimulation of the dorsal surface of the forepaw. The placing reaction was altered in such a way that the innate "dorsal placing" was subjected to extinction and was substituted for the newly acquired conditioned reaction in response to the ventral side stimulation. This alteration of placing reaction led to the inversion of the innate input-output relationship in the motor cortex. The neurons related to forepaw lifting-withdrawal began to be activated by tactile stimulation of the ventral rather than dorsal forepaw surface. Local cortical disinhibition by bicuculline application at the recording site qualitatively changed neither normal input-output relationships nor inverse relationships after placing reaction alteration. This suggests that alteration of the sensorimotor coordination in cat motor cortex is underlain by changes in excitatory rather than inhibitory connections.     

Revelation and identification of laminin in the structure of plasma membrane of ascitic Zajdela hepatoma cells

Cell dysdifferentiation during neoplastic transformation is a crucial problem of cell biology and oncology. Antigenic diversion of cancer cells is a typical characteristic of dysdifferentiation. It involves the appearance of antigens which are unusual for normal tissue of this type. Components organospecific for membrane proteins of normal kidney were previously found among plasma membrane proteins of hepatocellular rat tumors, rat hepatocytes after carcinogen treatment, and regenerating liver, respectively. In the present work we showed that a protein with mol. weight about 200 kDa reacting with laminin-1 immunoserum is the basic component of plasma membranes of the rat Zajdela hepatoma cells, which is responsive for organospecific anti-kidney immunoserum in Western blot. A mass-spectrometer analysis of trypsin proteolysis fragments was carried out in SDS-PAGE slices containing the investigated component. The analysis showed the presence of beta1, beta2 and alpha4 laminin chains peptides. The component with mol. weight about 180 kDa, found in the Western blot with laminin-1 immunoserum, was also subjected to the mass spectrometer analysis. As a result, a gamma1 laminin chain was found. An increased amount of laminin was revealed in the ascitic liquid and sera of rat with developed Zajdela hepatoma, in comparison with sera of normal rats. In addition, we found the appearance of laminin on the hepatocyte surface on the 4th day after hepatocarcinogen injection (N-diethylnitrosamine, DENA). Thus, for the first time tumor associated antigens were revealed and identified in the structure of plasma membranes of Zajdela hepatoma cells, being specific to rat kidneys. Our results allow to conclude that in the process of carcinogenesis in rat liver laminin synthesis occurs, which is also characteristic of the rat hepatoma Zajdela cells.     

Paradoxical vagal effects on the cardiac rhythm in cats

In anaesthetised cats, an increase in the vagal burst rate resulted in a paradoxical decrease of vagal bradycardia. This seems to be due to a shift of the vagal stimulus position towards early phase of cardiac cycle. The mechanism of this paradoxical effect depends on the magnitude of vagal chronotropic effect upon the time of vagal stimulus delivery within cardiac cycle.     

Magnetic resonance imaging in the diagnosis of gastric cancer: X-ray versus MRI anatomic findings

The paper assesses the present-day role of MRI in the diagnosis of gastric cancer. The authors consider the major prerequisites for the main aim of their study to be: 1) a dramatic incidence of diffuse (endophytic) gastric carcinoma, which requires significant correction of today's approaches to its diagnosis and 2) a rather biased and, in the authors' opinion, present-day mainly negative attitude towards MRI of the stomach as a diagnostic method for its tumor lesions. By applying the X-ray-MRI anatomic principle to the comparative study of MRI findings in 50 patients with predominantly gastric intramural carcinoma and in 25 patients without gastric tumors (controls), the authors present their methods for gastric MRI, the MRI semiotics of gastric cancer by concurrently touching upon a variety of problems that characterize the potentialities of MRI of the stomach in the diagnosis of its tumor lesions, including their differential diagnosis. As a result, the authors highly appreciate gastric MRI and consider this method to be included into the diagnostic algorithm of radiation techniques used in the diagnosis of gastric cancer, which should occupy its definite diagnostic place.     

The immunomorphologic analysis of innervation of chromaffin paraganglian cells of the mammalian arteries and heart

Innervation of chromaffin cells of paraganglia of the wall of mammalian large arterial vessels and heart (in rat, cat, and human) was studied by neuromorphological and immunohistochemical methods. There is established similarity in structure of specialized, "basket"-type nerve endings of the chromaffin cells (ChC) with pericellular nerve apparatuses of sympathetic and parasympathetic autonomic neurons. It is proposed to use immunohistochemical reaction for synaptophysin as method of selective detection of ChC of paraganglia and adrenal medulla. The conclusion is made that synaptophysin-positive terminals (SPPT) found on bodies of ChC and postganglionic neurons represent efferent, rather than afferent, synapses formed by myelinated axons of preganglionic fibers. It is suggested that ChC of paraganglia alongside with their characteristic endocrine function participate in complex mechanisms of chemoreceptor regulation of tissue homeostasis of mammalian blood vessels and heart.     

Abnormal condensation of meiotic chromosomes caused by the mei8 mutation in rye Secale cereale L

Inheritance of two spontaneous meiosis-specific mutations with similar cytologic phenotype was studied. Both mutations were independently obtained from two rye populations (Vyatka variety and weedy rye). Both mutations are recessive, allelic, and monogenically inherited; the corresponding gene is designated mei8. The mutant alleles of the gene cause abnormal meiotic chromosome structure expressed as irregular compaction along the chromosome length, chromatin stickiness at all stages of meiosis, and chromosome fragmentation in anaphase I.     

Cortical slow negative potentials during eye fixation and preparing of visually triggered saccades in a man

In 10 right-handed healthy subjects EEGs preceding saccades with mean latent periods were selectively averaged. Two standard schemes of visual stimulation were used: with immediate presentation of a peripheral target stimuli after the central fixation stimulus (a single step paradigm) and with the interval between the stimuli in 200 ms (GAP paradigm). Two waves of slow premotor negativity (early PMN1 and late PMN2) that appeared 930 +/- 79 and 609 +/- 82 ms, respectively, prior to a saccade onset were observed. The PMN2 was followed by the negative potentials N-3, N-2, and N-1 (saccadic initiation potential). It was found that in GAP stimulation condition the PMN1 was less pronounces and N-1 was increased as compared to the single step. These findings suggest that disengage of attention from the central point during the GAP period clears the saccadic system for decision making and initiation of a saccade. Under such conditions, the expectation of a visual target does not require a high level of nonspecific activation and motor attention.