The functional organization of the posterior lateral nucleus of the rat hypothalamus

It has been demonstrated that the posterior lateral thalamic nucleus of the rat receives information from the visual, somatic and auditory systems. Some of the neurons (63%) have a convergent input from these systems, although these neurons exhibit functional specificity with respect to the predominant inhibitory influence of the background activity of one of the sensory systems investigated. The other part of the neurons (37%) receives information only from the visual or somatic system, these neurons exhibiting excitatory phasic reaction to sensory stimuli.     

The functional role of CrkII in actin cytoskeleton organization and mitogenesis

Crk is a member of a family of adapter proteins predominantly composed of Src homology 2 and 3 domains, whose role in signaling pathways is presently unclear. Using an in situ electroporation system which permits the introduction of glutathione S-transferase (GST) fusion proteins into cells, we found that c-CrkII bound to p130(cas), but not to paxillin in serum-starved rat-1 fibroblasts overexpressing the human insulin receptor (HIRc cells) in vivo. 17 nM insulin stimulation dissociated the binding of c-CrkII to p130(cas), whereas 13 nM insulin-like growth factor-I, 16 nM epidermal growth factor (EGF), and 10% serum each showed little or no effect. We found that stress fiber formation is consistent with a change in the p130(cas).c-CrkII interactions before and after growth factor stimulation. Microinjection of either GST-Crk-SH2 or -Crk-(N)SH3 domains, or anti-Crk antibody each inhibited stress fiber formation before and after insulin-like growth factor-I, EGF, and serum stimulation. Insulin stimulation by itself caused stress fiber breakdown and there was no additive effect of microinjection. Microinjection of anti-p130(cas) antibody also blocked stress fiber formation in quiescent cells. Microinjection of the Crk-inhibitory reagents also inhibited DNA synthesis after insulin-like growth factor-I, EGF, and serum stimulation, but not after insulin. These data suggest that the complex containing p130(cas).c-CrkII may play a crucial role in actin cytoskeleton organization and in anchorage-dependent DNA synthesis.     

The adaptive reactions of the cardiorespiratory system in chronic bronchitis and its premorbid forms

AIM: Investigation of pulmonary ventilation, blood flow and cardiodynamics in subjects at risk of chronic nonspecific pulmonary disease (CNPD), prebronchitis (PB) and chronic bronchitis (CB). MATERIALS AND METHODS: 118 workers exposed to toxico-chemical factors underwent zonal rheography. RESULTS: At early stages of CB marked disorders of pulmonary ventilation and blood flow in the lungs were revealed. These disorders in subjects with threatened CNPD were regional and accompanied by a moderate increase in power inputs of the cardiorespiratory system. The maintenance of adequate pulmonary exchange in patients with PB entailed functional tension of the respiratory and cardiovascular systems that contributed to decompensation of adaptive mechanisms and occasionally to development of rheographic signs of pneumosclerosis in the lung zones with damaged ventilation and low perfusion of the pulmonary vessels. CONCLUSION: Overloading and decompensation of respiratory and cardial mechanisms of gas exchange regulation in the lungs in response to external damage may lead to development of myocardiodystrophy and pneumosclerosis which appear to be the "price of adaptation".     

The dynamic nature and age-related dependence of functional brain organization in attention

Intrahemispheric functional organization was studied during a task expectancy period with special reference to attention mechanisms. The estimation of coherence of functionally identical rhythmic EEG components was made to characterize the intracortical integration. Several factors influencing the possibility to make an adequate prognosis and to realize it were varied. Different types of the task were used. Subjects of different age (7, 9-10 years, young adults) and children of the same age differing by the brain maturity level were under study. It was shown that all factors studied have certain influence on the brain organization underlying the task preceding attention. Clear age differences as well as the lag between the possibility to formation and realization the prognosis in children were observed. Alternative "strategies" used in different ages to facilitate the task performance were analysed; underlying mechanisms were discussed.     

The development of adaptive body reactions after intensive physical loading]

The dependence between the activity parameters of muscarine antagonists in the prevention of haloperidol catalepsy in rats and those in tests characterizing the interaction of ligands and various subtypes of m-cholinoceptors was studied. It was established by constructing the mathematical dependence that blockade of m1-cholinoceptors increases, while that of m2-cholinoceptors reduces the antiparkinsonian activity of the drugs. The activity of the muscarine antagonist pentiphan in the prevention of haloperidol-induced catalepsy in rats exceeds the activity of such traditional antiparkinsonian drugs as cyclodol and amedin.     

Electrophysiologic analysis of the functional organization of cortico-cerebellar connections

The influence of associative (orbital-anterior, parietal) and projective (auditory, sensomotor) cerebral cortex areas stimulation on activity of the Purkinje neurons of cerebellar cortex was studied in adult cats under chloralose-nembutal or nembutal anesthesia. These reactions were compared with the responses to peripheral stimuli. Definite similarity in responses of the Purkinje cells to different cortical (associative, projective) stimuli was found both for types of neurons and their responsiveness. In responses of the Purkinje cells to peripheral stimulation there was no sharp similarity as it was in responses to cortical stimuli. So, in cortical stimulation almost similar number of neurons (above 50%) was excited and in peripheral stimulation the responsiveness of neurons had marked difference: to electrical stimulation of skin there were 44.6%, to auditory 34.2%, to visual 18.8% of neuron responses.     

Neuronal chemistry and functional organization in the primate visual system

Beginning with the first step of visual processing and proceeding outward from that point, the neurons involved in different aspects of vision are distinct. Stated simply, neurons doing different things look different. They often display distinct morphological features and they usually express different molecules. In addition, neurons that perform a common function usually aggregate together to form recognizable layers or compartments that can be studied in isolation because they are neurochemically distinct. Here is found, then, a junction of two major domains in neuroscience research, as discovery of molecular diversity among neurons is exploited to study organization and function of the primate visual system.     

Structural and functional organization of the enteric nervous system in the stomach

This report summarises some features of the gastric enteric nervous system in the guinea-pig model. Particular attention has been paid to relations between neurochemical properties, electrophysiological and putative function of enteric neurones. (1) Cholinergic and nitrergic neurones form separate neuronal populations. (2) Ascending neurones outnumbered descending ones. (3) Transmitter-phenotype and projection were related: cholinergic neurones were primarily ascending while nitrergic neurones were mainly descending. (4) The neurochemical code, i.e. the transmitter colocalisation, could be related to the function of enteric neurones. Colocalisation of substance P and/or enkephaline in cholinergic neurones was characteristic for ascending excitatory muscle neurones. Descending inhibitory muscle neurones were nitrergic often colocalising the neuropeptides neuropeptide Y (NPY) and vasoactive intestinal peptide (VIP). In the intrinsic innervation of the gastric mucosa NPY/VIP was abundant and colocalised in ascending cholinergic as well as descending nitrergic neurones. (5) The vast majority of ascending and descending interneurones were cholinergic and often colocalised NPY. (6) The majority of descending mucosa and descending inhibitory muscle neurones were tonically-firing neurones. Our results revealed the characteristics of some neural components within the enteric nervous system of the stomach which are involved in modulation of mucosa and muscle functions. It may be concluded that muscle and mucosa functions are under the control of the enteric nervous system which contains distinct populations responsible for motor and secretory activity.     

Electroencephalographic signs of compensatory reactions following stroke with location of the focus in the right and left cerebral hemispheres

The authors studied 41 patients with acute disorders of cerebral circulation, a focus in the right hemisphere and 14 with foci in the left hemisphere. The traits of compensatory reactions were studied according to the background and functional EEG, depending upon the severity, stage, localization and lateralization of focal vascular brain lesions. The authors indicate to a rigidity of clinical and EEG changes in patients with right hemispheric localization of the focus which is explained by the authors by disturbances of the higher cortical functions in these patients.     

The structural and functional organization of H-NS-like proteins is evolutionarily conserved in gram-negative bacteria

The structural gene of the H-NS protein, a global regulator of bacterial metabolism, has been identified in the group of enterobacteria as well as in closely related bacteria, such as Erwinia chrysanthemi and Haemophilus influenzae. Isolated outside these groups, the BpH3 protein of Bordetella pertussis exhibits a low amino acid conservation with H-NS, particularly in the N-terminal domain. To obtain information on the structure, function and/or evolution of H-NS, we searched for other H-NS-related proteins in the latest databases. We found that HvrA, a trans-activator protein in Rhodobacter capsulatus, has a low but significant similarity with H-NS and H-NS-like proteins. This Gram-negative bacterium is phylogenetically distant from Escherichia coli. Using theoretical analysis (e.g. secondary structure prediction and DNA binding domain modelling) of the amino acid sequence of H-NS, StpA (an H-NS-like protein in E. coli), BpH3 and HvrA and by in vivo and in vitro experiments (e.g. complementation of various H-NS-related phenotypes and competitive gel shift assay), we present evidence that these proteins belong to the same class of DNA binding proteins. In silico analysis suggests that this family also includes SPB in R. sphaeroides, XrvA in Xanthomonas oryzae and VicH in Vibrio cholerae. These results demonstrate that proteins structurally and functionally related to H-NS are widespread in Gram-negative bacteria.     

New developments in understanding the compensatory hematological reactions and their outcomes in local fractionated therapeutic gamma irradiation

A surgical treatment for central epithelial odontogenic ghost cell tumor is described. A brief review of the literature is given, and histopathology is discussed. The rationale for conservative treatment is presented, along with an illustrative case report.     

Spatial organization of microtubules and microfilaments in larval and adult salivary glands of Drosophila melanogaster

We examined the distribution of microtubules and microfilaments by conventional fluorescence microscopy and laser scanning confocal microscopy in larval and adult salivary glands of Drosophila melanogaster. The cells of the larval salivary gland epithelium were characterized by the same spatial distribution of microfilaments, whereas microfilament localization was more complex in adult salivary glands, showing some regional differentiation. Microtubules distributed throughout the cell cytoplasm of the larval salivary glands, whereas in adult glands they were mostly observed in the basal or apical cytoplasm of the cells. These observations were related to the secretory process and the mechanism of saliva discharge.     

The organized brain (an essay on the structure of functional brain organization). II

This communication is dedicated to the main postulates of the author's conception about systematic-structural organization of the cerebral functions--the principles of the space and temporal dispersion of the external and internal signals, the division of connections on the mono- and oligoprojections as well as hierarchic stage of fashion and modulation of entering information, the functional multifactory of the sensory stimuli as well as principles of overlapping both afferent and efferent influences and their mutual regulation. The principle of the change of dominant participation of one brain system to another within the behavioral act's formation is one of the main postulate of our conception. These data testify to very complicate dynamic character of the function's correlation with the brain structures. This correlation depends on the self cerebral organization as well as the role in its acting the diverse afferent messages and effector reactions.     

The lateral septal nucleus: its morphological and functional organization and its role in the formation of chronorhythms

The lateral septal nucleus (LSN) is the largest septal nucleus and occupies one of the most strategically important positions in the forebrain, connecting the structures of the limbic system with different sites of the brain stem. Such a situation obliges LSN not only to participate in the regulation, but also to implement overall coordination and modulation of various visceral and somatic functions. The review deals with the general characteristic of the septal complex, the functional morphology, pre- and postnatal ontogenesis, afferent and efferent connections, mediator and modulator nature of LSN fibers. Special attention is paid to the participation of LSN in the neuroendocrine regulation of the sexual system. On the basis of literature and our own experimental findings it is shown that the LSN is a chronoregulatory structure which is responsible for the biorhythmologic organization of the functions of the mammalian organism.     

High-precision neuromagnetic study of the functional organization of the human auditory cortex

Previous studies have proven that a dipole source analysis of the auditory evoked field is capable of providing evidence of the tonotopic organization of the human auditory cortex. To explore the nature of the estimated dipoles in greater detail, a single subject was extensively studied, and the estimated sources were registered in a three-dimensional reconstruction of the cortical surface derived from magnetic resonance images. The stimuli were 500-ms tone bursts with frequencies of 250, 500, 1,000, and 2,000 Hz (mean intensity of 60 dB SL). The total number of stimuli presented per condition was about 3,600 (36 independent experiments spread over 4 days). Using special postprocessing techniques, the relative localization accuracy could be enhanced to such an extent that differences in the dipole locations of 1 mm could be clearly distinguished. The results suggest that peak N1m (latency around 100 ms) arises from the planum temporale, whereas peak P2m (latency around 170 ms) appears to correspond to a center of activity in (or close to) Heschl's gyrus. The tonotopic organization found for the generator of N1m was consistent with earlier studies ("the higher the frequency the deeper the source"). However, additional findings (time dependence of the estimated sources; slightly different tonotopy obtained for field change; dependence of the estimated sources on the estimation technique) indicate that multiple areas are involved in the generation of N1m. Evidence of a frequency-dependent source location was found also for P2m.     

Domain organization and functional analysis of Thermus thermophilus MutS protein

MutS protein binds to DNA and specifically recognizes mismatched or small looped out heteroduplex DNA. In order to elucidate its structure-function relationships, the domain structure of Thermus thermophilus MutS protein was studied by performing denaturation experiments and limited proteolysis. The former suggested that T. thermophilus MutS consists of at least three domains with estimated stabilities of 12.3, 22.9 and 30.7 kcal/mol and the latter revealed that it consists of four domains: A1 (N-terminus to residue 130), A2 (131-274), B (275-570) and C (571 to C-terminus). A gel retardation assay indicated that T.thermophilus MutS interacts non-specifically with double-stranded (ds), but not single-stranded DNA. Among the proteolytic fragments, the B domain bound to dsDNA. On the basis of these results we have proposed the domain organization of T. thermophilus MutS and putative roles of these domains.