Guanine nucleotide-induced enhancement of affinity of dopaminergic membrane receptors of nerve tissues ofLymnaea stagnalis for agonists

Reception of labeled dopamine [7,8³H] DA (hereafter, DA) and of a D₁ receptor agonist, [³H] SKF 38393, in membranes from nerve tissues of the fresh-water lunged mollusc,Lymnaea stagnalis, was investigated. The presence of 10^–6 to 10^–5 M of guanine di- and triphosphate as well as of their nonhydrolizable analogs amplified the binding of agonists to membrane DA receptors, especially after EGTA addition. Replacement of EGTA with EDTA partly suppressed the binding amplification effect. Higher concentrations of guanine nucleotides (10^–3 to 10^–4 M) inhibited the binding of DA and of its agonists. The GDPS-dependent stimulation of agonist binding was found not to be induced by subunits of GTP-binding proteins (G proteins), immunologically similar to ₁-, ₂-, and G_o-subunits of G protein in vertebrates. Membrane phosphorylation by a catalytic subunit of cAMP-dependent protein kinase fully inhibited the stimulating effect of guanine nucleotides on the agonist binding to DA receptors and markedly depressed the DA-dependent GTPase activity.Neirofiziologiya/Neurophysiology, Vol. 25, No. 5, pp. 334–343, September–October, 1993.     

Identification of catecholamines in the rat brain and mollusk tissues using semithin slices and retrograde staining

The suggested technique allows revealing the transport-specific dye (primulin) and catecholamine fluorescence simultaneously in the same cell of brain. Intense fluorescence is observed when brain tissue is quickly dehydrated and embedded in the epoxy resin. The same method is suggested for the identification of catecholamines in the embryonal and juvenile tissues of gastropod Lymnaea stagnalis (Mollusca Pulmonata) without using of primulin dye.     

Characteristics of EEG signs of anxiety in human

Influence of anxiety (tested by Luscher) on the spatial organization of brain electrical activity was studied using multichannel EEG recording. In subjects with a high-level of anxiety, the level of coherence and spectral power of some high-frequency EEG components was higher in the parieto-temporal regions of both hemispheres than that in the opposite group. Solving the inverse problem (classification of individuals with one of the groups) made it possible to work out the criteria of automated evaluation of the anxiety level at the preclinic state of neuropsychic disorders. The EEG signs of the influence of increased anxiety on psychophysiological and cognitive processes and autonomic functions were analyzed. The EEG signs of increased anxiety in animals (rats) and humans were compared and some similarity of the spatial-frequency organization was revealed. The main difference consists in a greater activation of the left parieto-temporal area in humans, which is interpreted as a morphofunctional basis of verbalization of anxiogenic stimuli.     

Radiological assessment of protective countermeasures in the private sector of rural settlements in the Chernobyl nuclear power plant accident area

The effectiveness of countermeasures on private farms in rural settlements of the Russian Federation affected by the Chernobyl accident for the period of 1986-2005 was assessed. The averted collective doses to the residents of these settlements and the contribution of restrictive and agricultural countermeasures to dose reduction in the rural population have been estimated.     

A microsatellite-based consensus linkage map for species of Eucalyptus and a novel set of 230 microsatellite markers for the genus

Background  

Eucalypts are the most widely planted hardwood trees in the world occupying globally more than 18 million hectares as an important source of carbon neutral renewable energy and raw material for pulp, paper and solid wood. Quantitative Trait Loci (QTLs) in Eucalyptus have been localized on pedigree-specific RAPD or AFLP maps seriously limiting the value of such QTL mapping efforts for molecular breeding. The availability of a genus-wide genetic map with transferable microsatellite markers has become a must for the effective advancement of genomic undertakings. This report describes the development of a novel set of 230 EMBRA microsatellites, the construction of the first comprehensive microsatellite-based consensus linkage map for Eucalyptus and the consolidation of existing linkage information for other microsatellites and candidate genes mapped in other species of the genus.     

Glow discharge with electrostatic confinement of electrons in a chamber bombarded by fast electrons

A metal substrate is immersed in plasma of glow discharge with electrostatic confinement of electrons inside the vacuum chamber volume V ≈ 0.12 m³ filled with argon or nitrogen at pressures 0.005–5 Pa, and dependence of discharge characteristics on negative substrate potential is studied. Emitted by the substrate secondary electrons bombard the chamber walls and it results in electron emission growth of the chamber walls and rise of gas ionization intensity inside the chamber. Increase of voltage U between the chamber and the substrate up to 10 kV at a constant discharge current I _d in the anode circuit results in a manifold rise of current I in the substrate circuit and decrease of discharge voltage U _d between the anode and the chamber from hundreds to tens of volts. At pressure p < 0.05 Pa nonuniformity of plasma density does not exceed ∼10%. Using the Child-Langmuir law, as well as measurement results of sheath width d between homogeneous plasma and a lengthy flat substrate dependent on voltage U ion current density j _i on the substrate surface and ion-electron emission coefficient γ _i are calculated. After the current in circuit of a substrate made of the same material is measured, the γ _i values may be used to evaluate the average dose of ion implantation. The rate of dose rise at a constant high voltage U is by an order of magnitude higher than in known systems equipped with generators of square-wave high-voltage pulses. Application to the substrate of 10-ms-wide sinusoidal high-voltage pulses, which follow each other with 100-Hz frequency, results in synchronous oscillations of voltage U and ion current I _i in the substrate circuit. In this case variation of the sheath width d due to oscillations of U and Ii is insignificant and d does not exceed several centimeters thus enabling substrate treatment in a comparatively small vacuum chamber.     

Quantification of angiogenesis in estrogen receptor-positive and negative breast carcinoma

Background

The objective of this study was to evaluate angiogenesis according to CD34 antigen expression in estrogen receptor (ER)-positive and negative breast carcinomas.

Methods

This study comprised 64 cases of infiltrating ductal carcinoma in postmenopausal women divided into two groups: Group A: ER-positive, n = 35; and Group B: ER-negative, n = 29. The anti-CD34 monoclonal antibody was used as a marker for endothelial cells. Microvessel count was carried out in 10 fields per slide using a 40× objective lens (magnification 400×). Statistical analysis of the data was performed using Student's t-test (p < 0.05).

Results

The mean number of vessels stained with the anti-CD34 antibody in the estrogen receptor-positive and negative tumors was 23.51 ± 1.15 and 40.24 ± 0.42, respectively. The number of microvessels was significantly greater in the estrogen receptor-negative tumors (p < 0.001).

Conclusion

ER-negative tumors have significantly greater CD34 antigen expression compared to ER-positive tumors.

     

Comparative analysis of the zeta-crystallin/quinone reductase gene in guinea pig and mouse

zeta-Crystallin is a novel nicotinamide adenine dinucleotide phosphate:quinone reductase, present at enzymatic levels in various tissues of different species, which is highly expressed in the lens of some hystricomorph rodents and camelids. We report here the complementary DNA (cDNA) cloning of zeta-crystallin from liver libraries in guinea pig (Cavia porcellus), where zeta-crystallin is highly expressed in the lens, and in the laboratory mouse (Mus musculus), where expression in the lens occurs only at enzymatic levels. A 5' untranslated sequence different from the one previously reported for the guinea pig lens cDNA was found in these clones. We also report the isolation of genomic clones including the complete guinea pig zeta-crystallin gene and the 5' region of this gene in mouse. These results show the presence of two promoters in the guinea pig zeta-crystallin gene, one responsible for expression at enzymatic levels and the other responsible for the high expression in the lens. The guinea pig lens promoter is not present in the mouse gene. This is the first example in which the recruitment of an enzyme as a lens crystallin can be explained by the acquisition of an alternative lens- specific promoter.      

Quantification of the magnification and distortion effects of a pediatric flexible video-bronchoscope

Background

Flexible video bronchoscopes, in particular the Olympus BF Type 3C160, are commonly used in pediatric respiratory medicine. There is no data on the magnification and distortion effects of these bronchoscopes yet important clinical decisions are made from the images. The aim of this study was to systematically describe the magnification and distortion of flexible bronchoscope images taken at various distances from the object.

Methods

Using images of known objects and processing these by digital video and computer programs both magnification and distortion scales were derived.

Results

Magnification changes as a linear function between 100 mm (×1) and 10 mm (×9.55) and then as an exponential function between 10 mm and 3 mm (×40) from the object. Magnification depends on the axis of orientation of the object to the optic axis or geometrical axis of the bronchoscope. Magnification also varies across the field of view with the central magnification being 39% greater than at the periphery of the field of view at 15 mm from the object. However, in the paediatric situation the diameter of the orifices is usually less than 10 mm and thus this limits the exposure to these peripheral limits of magnification reduction. Intraclass correlations for measurements and repeatability studies between instruments are very high, r = 0.96. Distortion occurs as both barrel and geometric types but both types are heterogeneous across the field of view. Distortion of geometric type ranges up to 30% at 3 mm from the object but may be as low as 5% depending on the position of the object in relation to the optic axis.

Conclusion

We conclude that the optimal working distance range is between 40 and 10 mm from the object. However the clinician should be cognisant of both variations in magnification and distortion in clinical judgements.