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  • 1
    Electronic Resource
    Electronic Resource
    Selective stimulation of striatal dopamine receptors of the D1- or D2-class causes opposite changes of fos expression in the rat cerebral cortex (2003)
    Oxford, UK : Blackwell Science, Ltd
    European journal of neuroscience 17 (2003), S. 0 
    Details
    ISSN: 1460-9568
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: It has been suggested that activation of striatal neurons expressing D1 or D2 dopamine receptors elicits opposite changes in the net output of the basal ganglia circuitry and, consequently, in the functional interactions of the circuit with the cerebral cortex. In particular, it has been recently reported that striatal D1 receptors may regulate cortex function. To further address this issue, we mapped cerebral expression of Fos protein following intrastriatal stimulation of D1- or D2-class receptors in freely moving animals. Using permanent cannulas implanted in the right striatum, Sprague–Dawley rats received intrastriatal microinfusions of SKF 38393 (D1 agonist) or quinpirole (D2 agonist) or saline (controls), combined with systemic administration of D1 antagonist SCH 23390 or D2 antagonist eticlopride or saline. Animals treated with SKF 38393 showed dose-dependent, massive Fos increases in the motor, somatosensory, auditory, visual and limbic regions of the cerebral cortex, ipsilaterally to the injected striatum. Consistent Fos expression was also found in the injected striatum and, bilaterally, in the nucleus accumbens shell. These increases were effectively counteracted by systemic SCH 23390. Conversely, quinpirole did not induce significant cortical or striatal expression of Fos, which was instead observed after the systemic administration of eticlopride. Fos was not detected in any of the other basal ganglia nuclei, regardless of the dopamine agonists or antagonists used. Our results confirm that striatal D1 dopamine receptors play a central role in the modulation of cortical activity, thus providing additional information on the functional interaction between basal ganglia circuitry and cerebral cortex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1460-9568.2003.02520.x
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  • 2
    Electronic Resource
    Electronic Resource
    The Bogoljubov-Krylov averaging principle and the Cauchy problem for ordinary differential equations on the half-line (1995)
    Springer
    Nonlinear differential equations and applications 2 (1995), S. 231-244 
    Details
    ISSN: 1420-9004
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Abstract An existence and uniqueness theorem for the Cauchy problem for an ordinary differential equation on the half-line is proved under the hypothesis that the Cauchy problem for the averaged equation has a unique solution. A comparison between the exponential stability of the original equation and the averaged equation is also made. The results established below may be considered as anlogues of the classical Bogoljubov theorem for bounded solutions; they also provide a natural generalization of Mitropol'skij's averaging principle.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01295312
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  • 3
    Electronic Resource
    Electronic Resource
    Potentiation of medroxyprogesterone acetate antineoplastic activity by histodine in rat mammary tumours (1991)
    Springer
    Cancer chemotherapy and pharmacology 27 (1991), S. 271-277 
    Details
    ISSN: 1432-0843
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Summary The antitumour activity oa arginine, histidine and medroxyprogesterone acetate (MPA) was studied in female rats with dimethylbenzanthracene (DMBA)-induced mammary adenocarcinomas. After 15 days of treatment, regression was observed in 4 of 19 (21%), 3 of 18 (16.7%) and 22 of 59 (37.3%) tumours taken from rats given arginine, histidine or MPA, respectively. A total of 17 rats with tumours that had been non-responsive to MPA were then treated with MPA plus histidine for 15 more days; the growth of 3 lesions (17.6%) was arrested, and 5 tumours (29.4%) regressed markedly. The antineoplastic activity of MPA was found to be related to the oestrogen-(ER) and progesterone-receptor (PgR) concentrations measured in the tumours before the start of treatment, whereas that of arginine and histidine appeared to be independent of receptor status. A significant reduction in serum prolactin (PRL) levels occurred in rats that were responsive to MPA alone or to MPA plus histidine. In tumours taken from the same rats, the PRL receptor content was also significantly increased in comparison with that in non-responsive tumours. In contrast, serum PRL levels increased significantly in rats with tumours that were non-responsive to MPA, whereas no change in serum PRL or PRL receptor levels was observed in rats treated with arginine or histidine. Histidine showed the ability to increase the number of ERs and PgRs in responsive tumours; this could have been responsible for the unexpected potentiation of MPA antineoplastic activity. In contrast, the levels of ER and PgR in uteri taken from the same rats were not modified. Furthermore, the addition in vitro of histidine to cytosols obtained from tumours of control animals did not influence ER and PgR concentrations. These results suggest that the effect of histidine on ER and PgR levels is probably specific for tumour tissue and is not due to a direct activity.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00685111
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  • 4
    Electronic Resource
    Electronic Resource
    Histochimie des colorations dans le bloc à base de métaux, application aux coupes semi-fines (1971)
    Springer
    Histochemistry and cell biology 25 (1971), S. 310-321 
    Details
    ISSN: 1432-119X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Description / Table of Contents: Résumé Les auteurs décrivent une nouvelle méthode de coloration dans le bloc de tissu avec différents sels métalliques (alun de fer, tétroxyde d'osmium, acétate d'uranyl et chromeosmium) et l'hématoxyline. Cette technique est utilisée sur des tissus qui sont ensuite inclus en Araldit et permet d'obtenir des coupes semi-fines déjà colorées. Les auteurs ont cherché à préciser la spécificité de fixation du fer dans le tissu au moyen de méthodes d'extraction et de blocage. D'après leurs observations, le fer se fixerait aux groupes tissulaires chargés négativement. La nature des liaisons semble être de type électrostatique et complexe. Les liaisons complexes semblent prédominer au niveau des structures contenant des acides nucléiques.
    Notes: Summary The authors describe a new method of block staining for semifine sections with various metal salts (ferriammonium-sulphate, osmium tetroxyde, uranyl acetate, chromeosmium) and hematoxylin. They investigated the specificity of iron-alaun-hematoxylin with several extractions and blocking methods. According to their observations the dissociated iron is bounded to the negatively charged tissular groups. The nature of binding is thought to be electrostatic and coordinativ (complex). The last one is probably predominant in nucleic acids containing structures. This method seems to be encouraging for electron-histochemical investigations.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00278224
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  • 5
    Electronic Resource
    Electronic Resource
    Sur la morphologie des cellules nerveuses ganglionnaires sympathiques au cours de differentes maladies (1961)
    Springer
    Cell & tissue research 53 (1961), S. 492-544 
    Details
    ISSN: 1432-0878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Biology , Medicine
    Notes: Résumé L'Auteur a étudié 52 ganglions nerveux sympathiques (ganglion cervical inférieur, ganglion stellaire, les trois premiers ganglions de la chaîne sympathique lombaire, ganglion cœliaque) extirpés chirurgicalement à des patients souffrant des maladies suivantes: maladie de Bürger, maladie de Raynaud, troubles vasculaires périphériques déterminés par compression veineuse, lésions nécrotiques dues à congélation, mégadolichocôlon. Les ganglions nerveux ont été imprégnés selon les méthodes au nitrate d'argent de Cajal-de Castro et de Bielschowsky-Gros. Les résultats de cette étude peuvent être schématisés de la manière suivante: 1. Au cours des maladies mentionnées ci-dessus la morphologie des ganglions nerveux sympathiques est plus ou moins intensément modifiée. 2. L'histo-pathologie ganglionnaire a été fixée par des images assez précises qui peuvent être schématiquement groupées en trois variétés: modifications ganglionnaires à morphologie proliférative; modifications ganglionnaires à prédominance prolif érative mais comportant aussi des phénomènes dégénératifs; modifications ganglionnaires á prédominance dégénérative mais comportant aussi des phénomènes prolifératifs. Aucune de ces trois variétés de modifications ganglionnaires n'est nécessairement liée à une maladie donnée. Dans la maladie de Bürger le degré et l'intensité des modifications ganglionnaires sont étroitement liés à la gravité de la maladie; par contre le facteur ≪durée de la maladie ≫n'influence pas d'une manière appréciable la morphologie ganglionnaire. Dans un cas de mégadolichocôlon ont été étudiés pour la première fois (les Auteurs précédents se sont attachés seulement à l'étude du métasympathique du segment intestinal réséqué) le ganglion cœliaque et les ganglions de la chaîne sympathique lombaire extirpés chirurgicalement à un garçon souffrant de cette maladie. Des altérations notables reproduisant la gamme très étendue des lésions prolifératives et notamment dégénératives y ont été constatées et décrites. La mise en évidence de ces altérations accentue l'importance et la prédominance du composant nerveux proximal par rapport au distal dans la genèse de la mala- die de Hirschsprung.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF00339064
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  • 6
    Electronic Resource
    Electronic Resource
    Fixed point theorems for multivalued weighted maps (1980)
    Springer
    Annali di matematica pura ed applicata 126 (1980), S. 319-341 
    Details
    ISSN: 1618-1891
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Sunto Si dimostra un teorema di punto unito per una classe abbastanza ampia di mappe plurivalenti con pesi fra gli ANR metrici. Questo teorema contiene tanto i classici teoremi di punto fisso di Eilenberg-Montgomery, O' Neill, Darbo come i risultati di connettività di insiemi di punti fissi di famiglie parametrizzate di mappe dovuti a Leray e Browder.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01762514
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  • 7
    Electronic Resource
    Electronic Resource
    On the solvability of systems of non-convex inclusions in banach spaces (1991)
    Springer
    Annali di matematica pura ed applicata 160 (1991), S. 371-408 
    Details
    ISSN: 1618-1891
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mathematics
    Notes: Summary In this paper we study the existence of solutions for a system of upper semicontinuous, non necessarily convex, multivalued maps defined in abstract spaces. To this aim, we investigate the properties of the solution set of a multivalued equation. In particular we give conditions assuring the admissibility or the acyclicity of this map. The main tool is a technique to investigate fixed points of fiber-preserving maps. Some applications to boundary value problems for multivalued differential equations and for delay equations, are given.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/BF01764135
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  • 8
    Electronic Resource
    Electronic Resource
    Electron transfer mechanism in olefin polymerization (1995)
    New York, NY : Wiley-Blackwell
    Polymers for Advanced Technologies 6 (1995), S. 159-167 
    Details
    ISSN: 1042-7147
    Keywords: transition metal catalyst ; olefin polymerization ; electron transfer ; polymerization mechanism ; Chemistry ; Polymer and Materials Science
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology , Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Polymerization of olefins mediated by transition metal derivatives (Ziegler-Natta polymerization) is one of the most scientifically and industrially important processes of molecular conversion. Electron transfer mechanism could play a significant role in both heterogeneous and homogeneous catalysts. The catalytic activity strongly depends on the presence of two metallocene ligands attached to the transition metal (more commonly zirconium) which grants the valence form of zirconium in complexes of the type Cp2ZrX2(X=Cl or CH3) followed by the formation of the (Cp2ZrX)+ cation under the effect of a Lewis acid. On the other hand, Ti complexes with only one metallocene ligand give the syndiospecific polymerization of styrene, where the phenyl group appears to act as electron donor for the transition metal. The remarkable electronic effect of the metallocene groups in determining catalytic activity is demonstrated by the study of substituted metallocene ligands as well as other ligands around the metal. These effects cannot be, however, completely separated from steric effects which seem to be responsible for the impressive and versatile stereochemical control determined by symmetry properties of the transition metal complex.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/pat.1995.220060310
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