State of GABA-benzodiazepine receptor complex in diabetic neuropathy: effect of nicotinamide and nicotinoyl-GABA

An increase in GABA uptake by isolated rat brain synaptic endings as well as a decrease of pharmacologically active GABA analogue muscimol specific binding have indicated a physiologically drastic failure in realization of GABA-mediated inhibitory effects in CNS induced by diabetic encephalopathy. In spite of the impairment of inhibitory function of GABAergic transmission in diabetes a crucial activation of benzodiazepine receptors was determined, as it is tested by the increase in specific binding of flunitrazepam by synaptic membranes. This increase may play an important role in endogenous control of neural activity associated with the factors undefined so far. Using the approach that GABA, and several synthetic GABA agonists, appear to increase the affinity of the benzodiazepine recognition sites for such ligands, presumably by some allosteric mechanism, the findings concerning the in vitro binding assay technique confirm at least some of the functional characteristics observed between GABA and benzodiazepine receptors in vivo under pathological conditions. Indeed, the absence of activating effect on the affinity of flunitrazepam specific binding in the presence of micromolar concentrations of exogenous GABA implicate diabetes-induced alterations in coupling GABA- and benzodiazepine receptors that might be linked to changes in conformantial state of this membrane-bound complex and could partially explain diabetes-induced impairments of GABAergic transmission evaluated in the present study. Our study suggests that nicotinamide and especially GABA play an important role in improving the functioning of brain GABA-benzodiazepine complex impaired in diabetes through specific ligand-mediated mechanism and can be useful in the management of diabetes-associated brain failures.     

Detection of the DeltaF508 trinucleotide deletion in the human CFTR gene by UV immobilization on nylon of a complex of a PCR fragment with a highly specific probe

Deletion delta F508 has been revealed in PCR-amplified regions of human gene CFTR by color detection of the hybridization complex obtained by ligation of a tandem of short oligonucleotides on a DNA template followed by UV immobilization on nylon. The method allows reliable detection of the three-nucleotide deletion (insertion). The nonspecific signal depends on the nucleotide composition of the biotinylated tandem component. A significant level of the specific signal was achieved by using the PCR-amplified DNA fragments of different length (200-400 bp) irrespective of the position of the tandem-binding site in their sequences.     

A role and a place of ultrasound diagnosis of acute ileus

The main purpose of the authors is to present their view of a place of present-day ultrasonography in the diagnosis of acute small and large intestinal obstruction. A comparatively sizable material covering 218 verified cases of acute ileus, including 77 patients with large intestinal obstruction and 141 patients with impaired passage of the intestinal contents along the small bowel was used to outline the aspects of ultrasound techniques and the symptomatology of ileus, by differentiating its some types. Along with the general assessment of the methodological and semiotic aspects of ultrasound diagnosis of acute uleus, the authors emphasizes a role of sonography in the detection of large intestinal obstruction by outlining their modified procedure of ultrasound irrigoscopy. For greater objectivization of their positive assessment of the place of ultrasound in the diagnosis of acute ileus and large intestinal obstruction, the authors comparatively studied X-ray and ultrasound studies to reveal this pathology. In addition to their purely personal assessment of a role of ultrasound in the diagnosis of large intestinal obstruction, the lecture also shows its authors' opinion as to the organizational issues associated with the necessity of correcting the existing diagnostic algorithm to detect large intestinal obstruction.     

Rapid laboratory detection of antigens of infective agents of infections and technical means for their realization

A system of new accelerated and rapid methods for the detection of the antigens of the infective agents of plague, cholera, tularemia and brucellosis were developed on the basis of solid phase immunosuspension tests: the passive hemagglutination (PHA) test and the latex agglutination (LA) test. The immunological and physico-chemical properties of suspensions in the PHA and LA tests made it possible to use extraneous sources of energy (centrifugal acceleration and the electric field) to accelerate these tests. The results of the PHA and LA tests were registered with the use of a densitometer, model Ultrascan 2202, and a tester, model C 34014.2. To apply centrifugal acceleration and the electric field, a laboratory centrifuge and an electrophoretic microchamber were designed. Densitometry was carried out on modified plates and conductometry, with the use of modified electrodes. The time of obtaining the results of the PHA and LA tests was 15-30 minutes with the use of centrifugation and 2-5 minutes in the electric field, which made it possible to regard these tests as rapid.     

Allelic polymorphism of FMR1 gene CGG-repeat region in patients with impairment of natural and stimulated ovulation

The frequency of heterozygote carriers of (risk zone, alleles of FMR1 gene (40-47 CGG-repeats) was significantly higher in group of patients with ovarian dysfunction than in control group I. The tendency for higher frequency of those alleles was observed in patients with "poor response" to superovulation induction in IVF cycles. The average number of oocytes and follicles, which was obtained after stimulation of superovulation, was significantly decreased in FMR1 gene "risk zone" alleles carriers compared to patients with normal alleles of FMR1 gene. The average general dosage of exogenous gonadotrophin, necessary for superovulation induction was significantly higher in heterozygote carriers of FMR1 gene "risk zone" alleles than in patients with normal genotype. Thereby, the FMR1 gene "risk zone" alleles can be one of the hereditary susceptibility factors of impairment nature and stimulated ovulation.     

Kinetics of Semax penetration into the brain and blood of rats after its intranasal administration

The radioactive peptide analogue Semax corresponding to the ACTH(4-10) sequence (Met-Glu-His-Phe-Pro-Gly-Pro) with a molar radioactivity of 56 Ci/mmol labeled with tritium at the C-terminal Pro was prepared. The labeled peptide was used for studying the kinetics of Semax penetration into rat brain and blood after its intranasal administration (50 microg/kg, 20 microl of solution) to nonbred white rats of body mass 200-250 g. It was demonstrated that 0.093% of the total introduced radioactivity per gram can be found in the rat brain 2 min after the administration, 80% of this radioactivity belonged to Semax, and the rest, to its metabolites. The peptide undergoes rapid enzymatic degradation, with the tripeptide Pro-Gly-Pro prevailing in biological samples relative to the total content of Semax and its metabolites.     

Color categorization and the structure of perceptive color

This paper is an attempt to develop a coherent framework for understanding, simulating, and predicting color categories. The process of color categorization can be understood as a structuring of preceding color experience on the basis of statistical distribution of light in observers environment. A proposed computational model of color categorization includes: 1) distribution of R, G, B pixel values representing a sample of 630 color images of natural scenes (analogue of physical light experience); 2) transformation of the R, G, B pixel values into L*u*v* coordinates of the CIELUV color space (analogue of the process of color perception); 3) distribution of the L*u*v* coordinates representing the sample of the color images (analogue of perceived color experience); 4) k-means clustering algorithm of the L*u*v* coordinates representing the sample of the color images (analogue of the process of color categorization); 5) location and order of color clusters (analogue of location and order of color categories). The proposed computational model enables us to predict the location and order of color categories, being consistent with psycholinguistic data.     

The mechanism of acetate assimilation in purple nonsulfur bacteria lacking the glyoxylate pathway: acetate assimilation in Rhodobacter sphaeroides cells

The mechanism of acetate assimilation in the purple nonsulfur bacterium Rhodobacter sphaeroides, which lacks the glyoxylate pathway, is studied. It is found that the growth of this bacterium in batch and continuous cultures and the assimilation of acetate in cell suspensions are not stimulated by bicarbonate. The consumption of acetate is accompanied by the excretion of glyoxylate and pyruvate into the medium, stimulated by glyoxylate and pyruvate, and inhibited by citramalate. The respiration of cells in the presence of acetate is stimulated by glyoxylate, pyruvate, citramalate, and mesaconate. These data suggest that the citramalate cycle may function in Rba. sphaeroides in the form of an anaplerotic pathway instead of the glyoxylate pathway. At the same time, the low ratio of fixation rates for bicarbonate and acetate exhibited by the Rba. sphaeroides cells (approximately 0.1), as well as the absence of the stimulatory effect of acetate on the fixation of bicarbonate in the presence of the Calvin cycle inhibitor iodoacetate, suggests that pyruvate synthase is not involved in acetate assimilation in the bacterium Rba. sphaeroides.     

Effect of initial (spontaneous) arterial pressure on systemic hemodynamic orthostatic responses

In anesthetized rats, a reverse linear correlation of arterial pressure (AP) shifts was found within the range of initial AP over 95 mm Hg under the head-up tilts at 30 and 45 degrees. Within the range beneath 95 mm Hg this correlation was transformed into the direct one. Under 60 degrees tilt such correlation only occurred within the range beneath 95 mm Hg. The direction and degree of the arterial system responsiveness seems to depend on the tilt value as well as on the range of the initial AP.