Temporal location of the cardiac rhythm frequency structure based on discrete wavelet transform

Application of discrete wavelet transform to the temporal location of the frequency structure of the cardiac rhythm is considered. A method for analysis of tachograms (TGs) consisting of signal preparation, discrete wavelet transform, and a variant of estimation of the relative contributions of the rhythm frequency components is suggested. The use of the method is exemplified by analysis of a TG containing recordings of transitional processes, including the moments of a fixed respiration rate test, Valsalva test, and orthostatic test. The detected characteristics of changes in the frequency components are demonstrated by comparing them with the changes in the integral index of the total regulatory effect on the sinus node, which forms the response to these functional tests.     

A Structural and Thermodynamic Analysis of Novatrone and Flavin Mononucleotide Heteroassociation in Aqueous Solution by <Superscript>1</Superscript>H NMR Spectroscopy

A heteroassociation of the antitumor antibiotic novatrone (NOV) and flavin mononucleotide (FMN) in aqueous solution was studied by one- and two-dimentional ¹H NMR spectroscopy (500 MHz) to elucidate the molecular mechanism of the possible combined action of the antibiotic and the vitamin. The equilibrium reaction constants, the induced proton chemical shifts, and the thermodynamic parameters (ΔH and Δ_S) of the NOV and FMN heteroassociation were determined from the concentration and temperature dependences of proton chemical shifts of the aromatic molecules. The most favorable structure of the 1 : 1 NOV-FMN complex was determined by both the method of molecular mechanics (X-PLOR software) and the induced proton chemical shifts of the molecules. An analysis of the results suggests that the NOV-FMN intermolecular complexes are mainly stabilized by stacking interactions of their aromatic chromophores. An additional stabilization is possible due to intermolecular hydrogen bonds. It was concluded that the aromatic molecules of vitamins, in particular, FMN, can form energetically favorable heterocomplexes with aromatic antitumor antibiotics in aqueous solutions, which could result in a modulation of their medical and biological action.     

Common system of sparsely branched projection (reticular) NADPH-diaphorase neurons in the human forebrain formations built from densely branched cells

Cell morphometry with statistical analysis (using 9 parameters) of densely branched projection and sparsely branched reticular neurons was performed in the human forebrain formations built from densely branched projection neurons (the entorhinal cortex, striatum, nucleus accumbens basolateral amygdala, and dorsal thalamus). The reticular neurons included scattered reticular neurons and marginal reticular neurons of the dorsal thalamus. Golgi method and staining for NADPH-diaphorase were used. The scattered reticular neurons of different formations under study did not differ in any of the 9 parameters, whereas they significantly differed from the main projection neurons in 5 to 7 parameters (except one comparison with the difference in 2 parameters). Within the same formation, the scattered reticular and main projection densely branched neurons differed in 7 to 9 parameters. The endbrain scattered reticular neurons expressed NADPH-diaphorase, while in the dorsal thalamus only the medium marginal reticular neurons were NADPH-diaphorase-positive. Thus, a common system of ancient integrative reticular neurons expressing NADPH-diaphorase exists in the examined human forebrain formations. The evidence obtained by us and the literature data point to the projection nature of the scattered reticular neurons (to the V and VI neocortical layers), which suggests their modulatory influence on descending neocortical pathways.     

The role of substantia nigra in the cognitive activity in cats

The role of substantia nigra (SN) in the cat cognitive activity of different complexity degree, was investigated by original technique. Neurosurgery or neurochemical SN switching off leads to reliable disturbances of condition, reflexes, generalization and abstraction. Rehabilitation was possible after pharmacological stimulation of dopaminergic, partly GABA-ergic, and cholinergic systems. Stimulation of serotonin system was ineffective.     

Effects of estrogens on learning of rats with chronic brain cholinergic deficit in Morris water maze

A chronic deprivation of brain cholinergic functions in rats caused by intracerebroventricular injection of neurotoxin AF64A increases the escape latency in Morris water maze test as compared to control sham-operated animals. Measurements and analysis of rat movement tracks using an original computerized "Behavioral Vision" system revealed the ability of 17 beta-Estradiol and its synthetic isomer J-861 (both administered daily in per os dose 0.2 mg/kg during 7 days before and 10 days after a single intracerebroventricular injection of AF64A) to improve learning of the animals. Directivity of search trajectories was estimated by a novel index of track straightness. The introduction of an index of "passive swimming" made it possible to reveal episodes of immobility in water-maze behavior of AF64A-injected animals. Unlike J-861, 17 beta-Estradiol almost completely eliminated these episodes. The newly developed indices (especially straightness) seem to be very useful in differentiating learning ability of rats from a decrease in their mobility in the Morris water-maze test, in particular, in case of the estrogens under study.     

The neuropharmacological restoration of cognitive functions in cats after damage to the forebrain basal nuclei (Meynert's nucleus)]

The cognitive functions were studied on experimental model of Alzheimer's disease (destruction of the basal nuclei of Meynert in cats) using the stimulation and inhibition of Ach, GABA, and DA brain systems. Ach system was found to be essential to form generalization function, DA system to improve simple learning, and GABA system to involve in formation of complex associations.     

Selectivity of stimulus induced responses in cultured hippocampal networks on microelectrode arrays

Sensory information can be encoded using the average firing rate and spike occurrence times in neuronal network responses to external stimuli. Decoding or retrieving stimulus characteristics from the response pattern generally implies that the corresponding neural network has a selective response to various input signals. The role of various spiking activity characteristics (e.g., spike rate and precise spike timing) for basic information processing was widely investigated on the level of neural populations but gave inconsistent evidence for particular mechanisms. Multisite electrophysiology of cultured neural networks grown on microelectrode arrays is a recently developed tool and currently an active research area. In this study, we analyzed the stimulus responses represented by network-wide bursts evoked from various spatial locations (electrodes). We found that the response characteristics, such as the burst initiation time and the spike rate, can be used to retrieve information about the stimulus location. The best selectivity in the response spiking pattern could be found for a small subpopulation of neurones (electrodes) at relatively short post-stimulus intervals. Such intervals were unique for each culture due to the non-uniform organization of the functional connectivity in the network during spontaneous development.     

Creation of blast disease-resistant rice varieties with modern DNA-markers

Based on modern technologies of molecular DNA-markers, blast disease–resistance genes (Pi-ta, Pi-b, Pi-1, Pi-2, and Pi-33) were introgressed and pyramided into domestic rice varieties to give them longterm disease resistance. For that purpose, this case study uses SSR-markers closely linked to these genes, as well as intragenic markers of genes Pi-ta and Pi-b. Multiplex PCR systems were created for simultaneous identification of two resistance genes in the hybrid progeny for the following combinations: Pi-1 + Pi-2, Pi-ta + Pi-b, Pi-ta + Pi-33.     

New Data on the Biology of Kildin Cod Gadus morhua kildinensis (Gadidae) from Lake Mogilnoe (Kildin Island,the Barents Sea) Obtained by Echo Sounding and Underwater Photography

Journal of Ichthyology - The distribution of the Kildin cod Gadus morhua kildinensis in Lake Mogilnoye (Kildin Island, Barents Sea) is assessed based on the results of echo sounding and...     

The morphofunctional status of the hypothalamo-hypophyseal neurosecretory system and the energy processes in the gastric tissues following electromagnetic irradiation in the millimeter wave range

A single and double 15 and 30 min exposure to electromagnetic waves of millimetric range (60 GGz, 3 mW/cm2) of a biological active point (acupuncture point) EIII36 of intact male rats and those subjected to stress inhibits the functional activity of hypothalamo-hypophysis neurosecretory system, thyroid gland and cell elements of gastric glands the inhibition being mostly pronounced in animals under stress.