Septal nuclei in the regulation of vago-sensitive neurons activity of the solitary nucleus in cats

The descending influences of the septal nuclei (lateral nucleus--LSN and bed nucleus stria terminalis--BNST) on activity of viscero-sensory neurons of the nucleus of tractus solitarius (NTS) identified by stimulation of cervical part of the n. vagus were investigated in the cat anaesthetised by chloraloze-nembutal combination. It was found that out of 70 units recorded in the NTS area 50 were identified as those of primary and secondary input vagal neurons. Influence of single, paired and frequency stimulation on the septal structures was studied on these neurons. It was revealed that 30% (15 un) reacted by phase-specific response to the single stimulation of the septal nuclei. The latent period of initial excitation was in the range 5-25 ms. During the paired stimulation these neurons were not able to react to the second stimulus for the equal 10-300 ms. It was revealed that 34% (17 un) of the identified vagal neurons reacted by a tonic change of their spontaneous activity. The increase of frequency stimulation to 20 Hz evoked different changes of the rhythmical activity of the vagal neurons (increase, diminishing or inhibition). The study of interaction between central and peripheral signals in the solitary neurons induced blocking influence of descending septal discharge on the vagal test response. It is possible that the septal downward impulses reach the vago-sensitive solitary neurons indirectly through other structures of the limbic brain (amygdala, hypothalamus) and participate in modulation of the spontaneous activity of these neurons.     

Functional evaluation of the effectiveness of experimental reconstructive and plastic operations on the uterine horns

In the given experimental model, tubo-plastic surgery was done with the use of locally produced fibrin glue (Fk-1), and commercial product "Beriplast" (FRG). In the control group microsurgical technique was adopted in the uterine horn of rats. It was proved that Fibrin glue reduces the frequency of post operative adhesion formation in the area of anastomosis and the chance of pregnancy is increased in comparison to microsurgical techniques.     

Development of the hypothalamic-cortical interrelations in the ontogeny of the cat

Under chloralose narcosis, employing the evoked potentials method, studies have been made on the projection of the posterior hypothalamus to the frontal cortex in 1-30 days old kittens. The animals were divided into 3 age groups: 1-9, 10-19 and 20-30 days. Studies of the EPs in different points of pericruciate zone showed that these potentials are observed in all the investigated points from the first days of postnatal life. The latent period of responses in the youngest animals varied from 40 to 80 ms, exhibiting insignificant fluctuations depending on the cortical zone investigated. From the very beginning of postnatal life, in the same cortical zone the EPs may be observed in response to stimulation of the ischiadic nerve as well. In older animals, the latent period of the EPs decreases in all the points, the decrease being most significant near the crucial fissure. To the 30th day of postnatal life, the EPs in this zone with respect to their latency and configuration became quite similar to those in adult animals. In the third age period, the latency varies from 6 to 10 ms in the focus of maximum activity; with the removal of the recording electrode from this zone the latent period of the hypothalamo-cortical responses increases up to 30-40 ms. Overlapping of the EPs in response to central and peripheral stimulation was observed at all age periods.     

Production of fructooligosaccharide syrup from sucrose in combination with palatinose and trehalose

The fructofuranosidases (EC 3.2.1.26) of Aspergillus niger St-0018 and A. foetidus St-0194 were used to produce fructooligosaccharides (FOS) under periodic and continuous conditions. The incorporation of cells into calcium alginate gel gave the most efficient immobilized biocatalysts. The feasibility of transforming residual sucrose into palatinose and trehalulose using isomaltulose synthase (EC 5.4.99.11) was demonstrated.     

Electron microscopic and radioautographic study of nucleic acid synthesis in normal fatty tissue and lipomas

Electron microscopic radioautography was used to study nucleic acid synthesis in the normal fatty tissue and lipomas of different degree of maturity. Destroyed adipocytes were found in the investigated varieties of the fatty tissue. In a slow-growing Madelung's lipoma such adipocytes occurred in a greater amount than in the normal fatty tissue and nongrowing lipomas. 3H-Thymidine was mainly incorporated by endotheliocytes and pericytes, whereas Madelung's lipoma contained a greater number of labeled cells. Based on the data obtained it is suggested that the replenishment of adipocytes occurs at the expense of the proliferation of vascular wall cells.     

Morphological validation of the use of polyhydroxyethyl methacrylate-based x-ray contrast emboli for vascular occlusion

In the experiments on rabbits histological specimens with embolus radiopaque by iodides, bromides of silver and by (3-amino-2,4,6-triiodobenzyl) oil acid have been investigated 7 days after implantation. Optimum emboli were used in clinical practice during preoperative procedure for endovascular occlusion of liver and kidney arteries.     

Regulatory influence of hippocampus CA1 and CA3 areas on bulbar respiratory neurons under hypoxia

We studied the influence of stimulation of the CA1 and CA3 areas of the hippocampus on the impulse activity of respiratory neurons (RN) of the medulla oblongata under normal and oxygen deficiency conditions. Under conditions of normal atmospheric pressure, the electrical stimulation of the CA1 and CA3 areas of the hippocampus had mainly an inhibiting influence. In the initial phase, at a 4-5-thousand meter altitude, activation of frequent discharge of neurons occurred. In this situation, stimulation of the CA1 and CA3 areas was more accentuated than under conditions of normoxia. In the second phase (an altitude of 7.5-8 thousand meters), on the reduction of the impulse activity of neurons, stimulation of the CA1 and CA3 areas of the hippocampus induced untypical responses of these neurons.     

Position-dependence of stabilizing polar interactions of asparagine in transmembrane helical bundles

Recent studies with model peptides and statistical analyses of the crystal structures of membrane proteins have shown that buried polar interactions contribute significantly to the stabilization of the three-dimensional structures of membrane proteins. Here, we probe how the location of these polar groups along the transmembrane helices affect their free energies of interaction. Asn residues were placed singly and in pairs at three positions within a model transmembrane helix, which had previously been shown to support the formation of trimers in micelles. The model helix was designed to form a transmembrane coiled coil, with Val side chains at the "a" positions of the heptad repeat. Variants of this peptide were prepared in which an Asn residue was introduced at one or more of the "a" positions, and their free energies of association were determined by analytical ultracentrifugation. When placed near the middle of the transmembrane helix, the formation of trimers was stabilized by at least -2.0 kcal/mol per Asn side chain. When the Asn was placed at the interface between the hydrophobic and polar regions of the peptide, the substitution was neither stabilizing nor destabilizing (0.0 +/- 0.5 kcal/mol of monomer). Finally, it has previously been shown that a Val-for-Asn mutation in a water-soluble coiled coil destabilizes the structure by approximately 1.5 kcal/mol of monomer [Acharya, A., et al. (2002) Biochemistry 41, 14122-14131]. Thus, the headgroup region of a micelle appears to have a conformational impact intermediate between that of bulk water and the apolar region of micelle. A similarly large dependence on the location of the polar residues was found in a statistical survey of helical transmembrane proteins. The tendency of different types of residues to be buried in the interiors versus being exposed to lipids was analyzed. Asn and Gln show a very strong tendency to be buried when they are located near the middle of a transmembrane helix. However, when placed near the ends of transmembrane helices, they show little preference for the surface versus the interior of the protein. These data show that Asn side chains within the apolar region of the transmembrane helix provide a significantly larger driving force for association than Asn residues near the apolar/polar interface. Thus, although polar interactions are able to strongly stabilize the folding of membrane proteins, the energetics of association depend on their location within the hydrophobic region of a transmembrane helix.     

Magnetic resonance imaging in the diagnosis of different forms of endometriosis

The present paper examines the capacities of non-invasive MRI in the diagnosis of endometriosis. A standardized study algorithm is proposed, indications and methodology for MRI in different forms of endometriosis (EM) are specified. It is shown that in the diagnosis of different types of EM there are specific changes in the MR pattern of small pelvic organs, which allow one to make a differential diagnosis of this disease with a higher sensitivity (96%) and specificity (87%) as compared with ultrasound study. MRI makes it possible to assess the degree of invasion of endometrioid heterotopies into the wall of the intestine and cervix uteri with a high degree of accuracy and to judge the degree and extent of intestinal luminal narrowing. Diagnostic errors in solving these problems (as well as those associated with the detection of extragenital foci of EM in the small pelvis) are due first of all to movement artefacts a (respiration and intestinal motility) particularly in the presence of a significant adhesive process and/or after surgical intervention. MRI does not virtually yield false-negative conclusions in the diagnosis of different forms of genital endometriosis (less than 3%), which, in the authors' opinion, rather justifies some hyperdiagnosis (about 11%) made by this method in the diagnosis of endometriosis of the rectovaginal septum. MRI is a closing, specifying stage of instrumental diagnosis of not only EM, but also other small pelvic diseases.     

The limbical mechanisms of regulations of respiratory neurons in hypoxia conditions

The structures of limbic system have great integration in vegetative reactions. In the oxygen deficiency conditions we studied influence of irritation of limbical cortex, orbitofrontal cortes, hipotalamys, septum and hippocampus (CA1 and CA3 areas) on the impulse activity of respiratory neurons. Phases of hypoxia were the model of experiment. Irritation some of this structures on normoxia and 4-5 thousand meters higher, we discover inhibiting influense on respiratory neurons; some structures irritation had activating influence. In difficult conditions of hypoxia (7.5-8 thousand meters) on the reduction of the impulse activity of neurons, stimulation induced uncharacteristic reactions. Those different reactions of irritation limbic structures have regulation sense on respitatory neurons.