Functional asymmetry of the brain and effectiveness of sensorimotor function of oral cavity organs]

It has been established that in healthy persons functional brain asymmetry positively influences the effective performance of sensomotor function of oral cavity organs. Individual brain asymmetry is of considerable importance, the higher it is, the quicker the final results of sensomotor function are achieved. The character of brain asymmetry (right hand or left hand) does not practically influence the performance of sensomotor functions.     

The Impact of Alpha-Syntrophin Deletion on the Changes in Tissue Structure and Extracellular Diffusion Associated with Cell Swelling under Physiological and Pathological Conditions

Aquaporin-4 (AQP4) is the primary cellular water channel in the brain and is abundantly expressed by astrocytes along the blood-brain barrier and brain-cerebrospinal fluid interfaces. Water transport via AQP4 contributes to the activity-dependent volume changes of the extracellular space (ECS), which affect extracellular solute concentrations and neuronal excitability. AQP4 is anchored by α-syntrophin (α-syn), the deletion of which leads to reduced AQP4 levels in perivascular and subpial membranes. We used the real-time iontophoretic method and/or diffusion-weighted magnetic resonance imaging to clarify the impact of α-syn deletion on astrocyte morphology and changes in extracellular diffusion associated with cell swelling in vitro and in vivo. In mice lacking α-syn, we found higher resting values of the apparent diffusion coefficient of water (ADC_W) and the extracellular volume fraction (α). No significant differences in tortuosity (λ) or non-specific uptake (k′), were found between α-syn-negative (α-syn −/−) and α-syn-positive (α-syn +/+) mice. The deletion of α-syn resulted in a significantly smaller relative decrease in α observed during elevated K⁺ (10 mM) and severe hypotonic stress (−100 mOsmol/l), but not during mild hypotonic stress (−50 mOsmol/l). After the induction of terminal ischemia/anoxia, the final values of ADC_W as well as of the ECS volume fraction α indicate milder cell swelling in α-syn −/− in comparison with α-syn +/+ mice. Shortly after terminal ischemia/anoxia induction, the onset of a steep rise in the extracellular potassium concentration and an increase in λ was faster in α-syn −/− mice, but the final values did not differ between α-syn −/− and α-syn +/+ mice. This study reveals that water transport through AQP4 channels enhances and accelerates astrocyte swelling. The substantially altered ECS diffusion parameters will likely affect the movement of neuroactive substances and/or trophic factors, which in turn may modulate the extent of tissue damage and/or drug distribution.     

Study of the duplication of 17p11.2-12 chromosome region in the patients with hereditary motor and sensory neuropathy type 1A

Charcot-Marie-Tooth neuropathy (CMT) is one of the most common hereditary disorders, affecting 1:2500 individuals. CMT is a heterogeneous group of disorders characterized by chronic peripheral motor and sensory neuropathy. We have performed the detection of 1.5 Mb CMT1A tandem duplication in 17p11.2-12 chromosome region for autosome-dominant CMT1 patients and their relatives using the analysis of two (CA)n polymorphic microsatellite loci: 17S921 and 17S1358 localised in the duplication region. CMT1A duplication was found in three of five autosome-dominant CMT1 families. It has been shown that CMT1A duplication analysis is important for early differential diagnosis of CMT including prenatal diagnosis and genetic consulting in high risk families.     

Hemodynamic responses induced by modulation of the nitric oxide system and mitochondrial permeability in the medullary cardiovascular nuclei of rats

In acute experiments on normotensive rats and those with genetically determined hypertension (urethane anesthesia), we studied hemodynamic effects resulting from modulation of the activities of neuronal NO synthase (NOS-1), arginase II, and superoxide dismutase, and also of the mitochondrial permeability in medullary cardiovascular neurons. Unilateral microinjections of either a nitric oxide (NO) donor, sodium nitroprusside, or a substrate for endogenous NO synthesis, L-arginine, into the medullary cardiovascular nuclei (nucl. tractus solitarius, NTS, nucl. ambiguous, AMB, paramedian nucleus, PMn, and lateral reticular nucleus LRN) were shown to induce hemodynamic responses with rather similar dynamics in both normotensive and spontaneously hypertensive rats, although in the latter the reactions were more intense. Injections of an antagonist of NOS-1, N^G nitro-L-arginine (L-NNA), into the medullary nuclei under study in spontaneously hypertensive rats resulted in shifts of the systemic arterial pressure (SAP), which did not differ dramatically from those observed in normotensive animals. The data obtained serve as the background for the suggestion that the functional activity of NOS-1 is not fundamentally impaired under hypertension conditions, but, probably, the amount of the substrate for adequate synthesis of NO via the NO-synthase pathway of metabolism of L-arginine is insufficient. Considering this, we examined the functional activity of arginase, an enzyme that also, similarly to NOS, uses L-arginine for metabolic transformation. Injections of antagonists of arginase, norvaline or α-difluoromethylornithine hydrochloride (DFMO), into populations of the medullary neurons under study induced similar shifts of the SAP in normotensive and spontaneously hypertensive rats, and those responses did not differ significantly from the effects of inhibition of the NOS-1 activity. Thus, both the above-mentioned enzymes are potentially active in normotensive and spontaneously hypertensive rats; so, a possibility for their competition for L-arginine in certain situations does exist. Modulation of the mitochondrial permeability in medullary cardiovascular neurons in normotensive and spontaneously hypertensive rats induced significant hemodynamic effects. In particular, an increase in the mitochondrial permeability in the medullary cardiovascular nuclei by injections of an inductor of mitochondrial permeability transition pore (mPTP) opening, phenylarsine oxide (PAO), was accompanied by SAP drops in both normotensive and spontaneously hypertensive rats; the effects were dose-dependent and, in some cases, irreversible. A decrease in the mitochondrial permeability in the neurons under study by injections of an inhibitor of mPTP, melatonin, induced mostly hypertensive responses, although in some experiments we observed hypotensive and two-phase responses. Neirofiziologiya/Neurophysiology, Vol. 39, No. 3, pp. 232–244, May–June, 2007.     

Method for endogenous formaldehyde evaluation in animal organism

A method for endogenous formaldehyde (FA) level evaluation has been worked out. The method involves the administration of dimedone, which forms the stable complex with FA, and the determination of formaldimedone concentration in biological samples by the fluorescence approach. The method was tested on rat's models of FA metabolism modulation. Animals received FA (10 mg/kg); or methylamine - substrate of FA-generating enzyme SSAO, (250 mg/kg); or semicarbazide - SSAO inhibitor, (200 mg/kg). Concentration of FA bound with dimedone in the liver tissue were, correspondingly: 7.5 +/- 1.5 mkg/kg; 5.4 +/- 0.9 mkg/kg; 2.4 +/- 0.7 mkg/kg; control - 4.2 +/- 1.4 mkg/kg. Obtained data indicate, that the elaborated method gives reliable information about FA level.     

Prediction of the three-dimensional structure of aflatoxin of Aspergillus flavus by homology modelling

Aflatoxins are polyketide-derived secondary metabolites produced by Aspergillus spp. The toxic effects of aflatoxins have adverse consequences for human health and agricultural economics. The aflR gene, a regulatory gene for aflatoxin biosynthesis, encodes a protein containing a zinc-finger DNA-binding motif. AFLR-Protein three-dimensional model was generated using Robetta server. The modeled AFLR-Protein was further optimization and validation using Rampage. In the simulations, we monitored the backbone atoms and the C-α-helix of the modeled protein. The low RMSD and the simulation time indicate that, as expected, the 3D structural model of AFLR-protein represents a stable folding conformation. This study paves the way for generating computer molecular models for proteins whose crystal structures are not available and which would aid in detailed molecular mechanism of inhibition of aflatoxin.     

Formaldehyde metabolism in semicarbazide intoxication

Subchronic administration of semicarbazide in the experiment with the rats was used to reduce the formaldehyde level in the organism in order to reveal the interaction between formaldehyde metabolism and biochemical parameters, which define the oxidant-antioxidant system condition and NO metabolism. It has been found that under semicarbazide impact the generation of free radicals, ROS, nitrite and nitrate were enhanced while aldehydes level was reduced that resulted from not only semicarbazide effect like the aldehydes acceptor, but the formaldehyde synthesis slowdown and acceleration of its transformation into format as well. We suppose that formaldehyde plays certain role in the development of connective tissue pathology.     

Systemic Administrations of Water-Dispersible Single-Walled Carbon Nanotubes: Activation of NOS in Spontaneously Hypertensive Rats

Neurophysiology - Priority data have been obtained on the effects of repeated systemic administrations of water-dispersible single-walled carbon nanotubes (SWCNTs) to spontaneously hypertensive...