TY - THES A1 - Schlör, Joachim T1 - Carl R. Rogers - Ein pädagogischer Klassiker? Biographische Rekonstruktionen N2 - not available KW - Carl Rogers Biographie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-231708 ER - TY - JOUR A1 - Waelbroeck, M. A1 - Camus, J. A1 - Tastenoy, M. A1 - Feifel, R. A1 - Mutschler, E. A1 - Tacke, R. A1 - Strohmann, C. A1 - Rafeiner, K. A1 - Rodrigues de Miranda, J. F. A1 - Lambrecht, G. T1 - Binding and functional properties of hexocyclium and sila-hexocyclium derivatives to muscarinic receptor suhtypes JF - British Journal of Pharmacology N2 - 1 We have compared the binding properties of several hexocyclium and sila-hexocyclium derivatives to muscarinic Ml receptors (in rat brain, human neuroblastoma (NB-OK I) cells and calf superior cervical ganglia), rat heart M2 receptors, rat pancreas M3 receptors and M4 receptors in rat striatum, with their functional antimuscarinic properties in rabbit vas deferens (Ml/M4-like), guinea-pig atria (M2), and guinea-pig ileum (M3) muscarinic receptors. 2 Si la-substitution (C/Si exchange) of hexocyclium (~ sila-hexocyclium) and demethyl-hexocyclium (~demethyl-sila-hexocyclium) did not significantly affect their affinities for muscarinic receptors. By contrast, sila-substitution of demethoxy-hexocyclium increased its affinity 2 to 3 fold for all the muscarinic receptor subtypes studied. 3 The p-fluoro- and p-chloro-derivatives of sila-hexocyclium had lower affinities than the parent compound at the four receptor subtypes, in binding and pharmacological studies. 4 In binding studies, o-methoxy-sila-hexocyclium (Ml = M4 ~ M3 ~ M2) had a much lower affinity than sila-hexocyclium for the four receptor subtypes, and discriminated the receptor subtypes more poorly than sila-hexocyclium (Ml = M3> M4> M2)' This is in marked contrast with the very clear selectivity of demethoxy-sila-hexocyclium for the prejunctional MtlM4-like heteroreceptors in rabbit vas deferens. 5 The tertiary amines demethyl-hexocyclium, demethyl-sila-hexocyclium and demethyl-o-methoxy-silahexocyclium had 10 to 30 fold lower affinities than the corresponding quaternary ammonium derivatives. KW - Hexocyclium/sila-hexocyclium derivatives KW - o-methoxy-sila-hexocyclium KW - muscarinic receptor subtypes KW - structure/ affinity relationships KW - binding/functional correlations KW - muscarinic receptor antagonists Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128265 VL - 112 ER - TY - JOUR A1 - Herbert, M. K. A1 - Holzer, P. T1 - Interleukin-1ß enhances capsaicin-induced neurogenic vasodilatation in the rat skin JF - British Journal of Pharmacology N2 - No abstract available. KW - Interieukin-1ß KW - capsaicin KW - afferent nerve stimulation KW - cutaneous hyperaemia KW - neurogenic infiammation KW - sensitization of afferent nerve endings KW - proinfiammatory action KW - prostaglandins KW - calcitonin gene-related peptide (CGRP) Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-128171 VL - 111 ER - TY - CHAP A1 - Hoffmann, Joachim T1 - Die visuelle Identifikation von Objekten T2 - Wahrnehmung N2 - No abstract available. KW - Wahrnehmung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127745 PB - Hogrefe CY - Göttingen ER - TY - JOUR A1 - Hoffmann, Joachim T1 - Der implizite Erwerb von Handlungswissen JF - Psychologie und Sport : Zeitschrift für Sportpsychologie N2 - Der Beitrag beschäftigt sich mit Überlegungen zum Aufbau verhaltenssteuernder Strukturen. Er geht von dem Konzept de simpliziten Lernens aus, nach dem sich die Steuerung des Verhaltens, wenigstens unter bestimmten Bedingungen, unbewusst, aufmerksamkeitsunabhaengig und unwillkürlich an strukturelle Eigenschaften der Umgebung anpasst. Eine kritische Analyse einschlägiger Untersuchungen führt zu einer hypothetischen Lernstruktur, die es gestattet zu lernen, unter welchen Bedingungen welche Verhaltensakte zu welchen Konsequenzen führen. Der Lernprozess, so wird angenommen, wird in dieser Struktur von einem fundamentalen Beduerfnis nach sicherer Antizipierbarkeit von Verhaltenskonsequenzen getrieben. Eine Pilotstudie, die von diesen Annahmen ausgeht, wird ebenso diskutiert wie moegliche Anwendungen bei der Gestaltung von Trainingsprozessen im Sport. KW - Handlungspsychologie KW - Lernen KW - Lernpsychologie KW - Wissen Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-127709 VL - 8 IS - 2 ER - TY - INPR A1 - Kiesler, Reinhard T1 - Zum Stand der Forschung auf dem Gebiete der französischen Umgangssprache (1994) N2 - Der Artikel gibt einen Überblick über die Forschungen zur französischen Umgangssprache von den Anfängen bis etwa 1992 in vier Abschnitten: 1. Die Anfänge, 2. die Sprachschichtenforschung, 3. die Beiträge von Soziolinguistik und Varietätenlinguistik und 4. die Arbeiten der "Gegenwart" um 1990. Eine Zusammenfassung und eine ausführliche Bibliographie schließen den Forschungsbericht ab. Berücksichtigt werden alle sprachlichen Ebenen von der Aussprache über den Wortschatz bis zur Grammatik. Wo es angebracht erscheint, sind Hinweise auf Arbeiten zu anderen Umgangssprachen angeführt. KW - Französisch KW - Umgangssprache KW - Variationslinguistik KW - Soziolinguistik KW - Stilistik KW - Aussprache KW - Wortschatz KW - Grammatik Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-103365 ER - TY - CHAP A1 - Wilhelm, Gernot T1 - Hymnen der Hethiter N2 - no Abstract available KW - Alter Orient KW - Hymne KW - Aufsatzsammlung KW - Griechenland KW - Ägypten KW - Sumerisch Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87862 ER - TY - JOUR A1 - Wilhelm, Gernot T1 - Bemerkungen zur urartäischen Paläographie N2 - no Abstract available KW - Alter Orient KW - Kultur KW - Geschichte KW - Aufsatzsammlung KW - Hrouda KW - Barthel KW - Bibliographie KW - Funde Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87784 ER - TY - JOUR A1 - Heiser, A. A1 - Müller-Ruchholtz, W. A1 - Ulrichs, Karin T1 - Isolation of Islets of Langerhans: Improvement of the Isolation Technique Using the Pig Model. N2 - During the last view years, interest in pancreatic islet transplantation for the cure of type I diabetes has increased markedly. A serious barrier to clinical islet transplantation is the isolation of a sufficient mass of viable and functional islets. We used a porcine islet isolation model to examine various parameters of the isolation procedure and to improve isolation technique. KW - Langerhans-Inseln Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87765 ER - TY - BOOK A1 - Wilhelm, Gernot T1 - Medizinische Omina aus Hattuša in akkadischer Sprache N2 - No abstract available. KW - Akkadisch KW - Keilschrifttext KW - Diagnose KW - Boğazkale KW - Krankheitsverlauf KW - Symptomatologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87733 ER - TY - JOUR A1 - Schneider, Wolfgang A1 - Visé, Mechthild A1 - Reimers, Petra A1 - Blaesser, Barbara T1 - Auswirkungen eines Trainings der sprachlichen Bewußtheit auf den Schriftspracherwerb in der Schule T1 - Effects of a phonological awareness training on the acquisition of literacy N2 - Mit der vorliegenden Trainingsstudie wird der Versuch unternommen, Ergebni e eines Förderprograrnms zur sprachlichen Bewußtheit (Lundberg, Frost & Petersen 1988) im deutschsprachigen Raum zu validieren. An unserer Replikationsstudie nahmen insgesamt 371 Kinder teil, von denen 205 Kinder einer Trainingsgruppe und 166 Kinder einer Kontrollgruppe zugewiesen wurden. Das Förderprograrnm bestand aus Sprachspielen, die über einen Zeitraum von zirka 6 Monaten täglich 15 Minuten in den Kindergartengruppen durchgeführt wurden. Die Kontrollgruppe erhielt keine spezielle Förderung, sondern nahm am regulären Kindergartenprogramm teil. Indikatoren der sprachlichen Bewußtheit und weitere metalinguistische und kognitive Variablen wurden unmittelbar vor und nach der Förderung erhoben. Zu Beginn des ersten Schuljahres wurde ein metalinguistischer Transfertest, gegen Ende dann ein Rechtschreibtest durchgeführt. Die Befunde replizieren die Ergebnisse der dänischen Ausgangsstudie insofern, als kurz- und langfristige Trainingseffekte gesichert werden konnten. Sie verdeutlichen jedoch zusätzlich, daß die Qualität der Förderung für die Langzeitwirkung entscheidend war. N2 - A training study based on the design of Lundberg, Frost & Petersen (1988) was conducted to improve German Kindergarteners' phonological awareness. A total of 371 Kindergarteners participated in the study. The training group (N = 205) participated in a metalinguistic program that lasted for about six months ( 15 minutes per day). The control group did not receive any specific training but participated in the regularkindergartenpro gram. Indicators of phonological awareness and other metalinguistic and cognitive variables were assessed both before and after the training. Further, a metalinguistic transfer test and a spelling test were given at the beginning and the end of first grade, respectively. The results confirmed those of the Danish study in that short- and long-term training effects were obtained. They also illustrate, however, that the quality of training had a significant effect on long-term maintenance. KW - phonologische Bewusstheit KW - Übung KW - Sprache KW - Lernen Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87491 ER - TY - JOUR A1 - Schneider, Wolfgang T1 - Lese-Rechtschreib-Forschung heute: Einführung T1 - Reading and writing research today: lntroduction N2 - Es wird eine Kurzübersicht über relevante Strömungen der Lese-Recht chreib-Forschung gegeben. Nachdem die sog. Legasthenieforschung aufgrund konzeptueller und methodologischer Probleme in die Kritik geraten war, treten gegenwärtig eher theorieorientierte An ätze in den Vordergrund. euere Modelle zum Schriftspracherwerb haben zahlreiche Längsschnittstudien stimuliert, die die Relevanz metalinguistischer Fähigkeiten für den päteren Schriftspracherwerb dokumentieren. N2 - This article presents a short overview of current trend in research on reading and pelling. First, specific conceptual and methodological shortcomings of research on dyslexia are briefly discussed. Next, current developmental model of reading and spelling are introduced. Finally, the importance of longitudinal tudie influenced by those models and focusing on the rote of metalinguistic abilities in the acquisition of reading and spelling skills is highlighted. KW - Leseforschung KW - Schreiben KW - Forschung Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87489 ER - TY - JOUR A1 - Gruber, Hans A1 - Renkl, Alexander A1 - Schneider, Wolfgang T1 - Expertise und Gedächtnisentwicklung: Längsschnittliche Befunde aus der Domäne Schach N2 - Die vorliegende Arbeit ging zwei Hauptfragestellungen nach: (I) Inwiefern unterscheiden sich Experten in der Domäne Schach von Aussteigern aus der Expertisekarriere? (2) Wie verändern sich schachspezifische und generelle Gedächtnisparameter über einen Zeitraum von mehreren Jahren? Es wurden 27 Experten und Novizen mit einem durchschnittlichen Alter von knapp 12 Jahren zum ersten Meßzeitpunkt und von 16 Jahren zum zweiten Meßzeitpunkt untersucht. Die Aussteiger aus der Expertisekarriere zeigten bereits bei der Erstmessung schlechtere schachspezifische Gedächtnisleistungen als die übrigen Experten; die Annahme selektiver Aussteiger, die die Aussagekraft querschnittlicher Experten-Novizen-Vergleiche in Frage stellt, wird damit bestätigt. Sowohl für die Experten als auch für die Novizen zeigte sich ein Anstieg der schachspezifischen Gedächtnisleistung von der Erst- zur Zweitmessung. Während dafür bei Experten domänenspezifische Faktoren verantwortlich sein dürften, scheint dies bei Novizen auf die Entwicklung allgemeiner Gedächtnisparameter zurückzugehen. KW - Expertise KW - Gedächtnis KW - Schach Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87473 ER - TY - JOUR A1 - Schneider, Wolfgang T1 - Der Übergang in weiterführende Schulen nach dem 4. oder 6. Grundschuljahr? Theoretische Analysen und empirische Befunde zur Prognose des Schulerfolgs N2 - No abstract available. KW - Grundschule KW - Schulübergang KW - Zeitpunkt Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87465 ER - TY - CHAP A1 - Schneider, Wolfgang T1 - Methodische Ansätze der empirischen Erziehungs- und Sozialisationsforschung N2 - No abstract available. KW - Methode KW - Sozialisation KW - Pädagogik KW - Psychologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87454 ER - TY - JOUR A1 - Winkler, Christoph A1 - Wittbrodt, Joachim A1 - Lammers, Reiner A1 - Ullrich, Axel A1 - Schartl, Manfred T1 - Ligand-dependent tumor induction in medakafish embryos by a Xmrk receptor tyrosine kinase transgene N2 - Xmrk encodes a subclass 1 receptor tyrosine kinase (RTK) which has been cloned from the melanomainducing locus Tu of the poeciliid fish Xiphophorus. To demonstrate a high oncogenic potential in vivo we transferred the gene into early embryos of the closely related medakafish. Ectopic expression of the Xmrk oncogene under the control of a strong, constitutive promoter (CMVTk) led to the induction of embryonic tumors with high incidence, after short latency periods, and with a specific pattern of affected tissues. We demonstrate ligand-dependent transformation in vivo using a chimeric receptor consisting of the extracellular and transmembrane domains of the human EGF receptor (HER) and the cytoplasmatic domain of Xmrk. Expression of the chimeric receptor alone does not lead to ldnase activation or induction of tumors. Coexpression of the chimera with its corresponding ligand, human transforming growth factor alpha (bTGF(X), however, results in the activation of the chimeric RTK. In injected fish embryos the induction of the neoplastic growth is observed with similar incidence and tissue distribution as in embryos carrying the native Xmrk oncogene suggesting that the ligand as well as factors downstream of tbe RTK are required for tumor formation. In this study we show single-step induction of tumors by ectopic expression of RTKs in vivo substantiating tbe significance of autocrine stimulation in RTK induced tumors in vertebrales. KW - Japankärpfling KW - Ligand KW - Tumor Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-87107 ER - TY - JOUR A1 - Ulrichs, Karin A1 - Eckstein, V. A1 - Korsgren, O. A1 - Tibell, A. A1 - Groth, C. G. A1 - Müller-Ruchholtz, W. T1 - Characterization of natural and induced human xenophile antibodies before and after transplantation of the fetal porcine endocrine pancreas N2 - No abstract available. KW - Bauspeicheldrüse KW - Antikörper KW - Transplantation Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86985 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Kropfgans, Martin A1 - Tafel, Andrea A1 - Wiesenberger, Frank A1 - Sheldrick, William S. A1 - Mutschler, Ernst A1 - Egerer, Hansjörg A1 - Rettenmayr, Nikola A1 - Gross, Jan A1 - Waelbroeck, Magali A1 - Lambrecht, Günter T1 - (Hydroxymethyl)diphenyl(piperidinoalkyl)silane des Typs (HOCH2)(C6H5)2Si(CH2)nNC5H10 (n = 2,3) und deren Methoiodide: Synthese, Struktur und antimuscarinische Eigenschaften N2 - No abstract available. KW - (Hydroxymethyl)diphenyl(piperidinoalkyl)silanes KW - Sila-pridinol KW - Sila-difenidol KW - muscarinic antagonists KW - muscarinic receptors Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86904 ER - TY - JOUR A1 - Sponholz, Barbara T1 - Phénoménes karstiques dans les roches siliceuses au Niger oriental N2 - Dans le Niger oriental, des phénomenes karstiques sont fréquents dans les roches siliceuses: gres, silcretes, croûtes ferrugineuses, roches cristallines. A partir des études géomorphologiques et micromorphologiques, on peut conclure a une kartsification, au sense de production de formes par dissolution. Les résultats permettent de dater du Tertiaire inférieur la principale période de karstification. La répartition régionale des formes induites par cette karstification indique une dépendance probable des conditions paléoclimatiques. Actuellement le karst influe encore sur le développement des autres formes de relief. N2 - In North-Eastern Niger karstic features occur commonly in siliceous rocks (sandstones, silcretes, ironcrusts, crystalline). On the base of geomorphological field studies and micromorphological analyses karst forming caused by rock solution is verified. The results render possible the datation of the main karstification period in Early Tertiary. The widespread distribution of similar results indicates the dependance of karstification on palaeoclimatic conditions; actually the karstic systems influence significantly the development of othe landforms. KW - silicate karst KW - geomorphology KW - palaeoclimatology KW - Sahara KW - Sahel KW - Niger KW - karst siliceux KW - geomorphologie KW - paléoclimat KW - Sahara KW - Sahel KW - Niger Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86833 ER - TY - JOUR A1 - McCarron, R. M. A1 - Wang, L. A1 - Sirén, Anna-Leena A1 - Spatz, M. A1 - Hallenbeck, J. M. T1 - Adhesion molecules on normotensive and hypertensive rat brain endothelial cells N2 - The intercellular adhesion of circulating leukocytes to vascular endothellum ls a prerequisite for leukocyte emigration from the blood to extravascular tlssues. This process is facllltated by adhesion molecules on the surfaces of both the vascular endothelial cells and the leukocytes. The experiments presented here demonstrate for the first time that the leukocyte adhesion receptor, intercellular adhesion molecule-1, is constitutively expressed on cultured cerebromicrovascular endothelial cell lines derived from both spontaneously hypertensive (SHR) rats and normotensive WistarKyoto (WKY) rats. Both cultures contained simliar numbers of cells constitutively expressing this adhesion molecule (31.4% and 29.6%, respectlvely). Adhesion molecule expression was up-regulated by interleukin-1 ß, tumor necrosis factor-a, interferon-y and lipopolysaccharide in a dose- and time-dependent manner. Both cultures exhibited similar maximum levels of adhesion molecule up-regulation to optimal concentrations of all three cytokines. However, SHR endothelial cells were moresensitive to all three cytokines; significantly higher levels of intercellular adhesion molecule-1 expresslon were seen on SHR as opposed to WKY endothelial cells cultured with sub-optimal cytokine concentrations. It was also observed that lipopolysaccharide up-regulated intercellular adhesion molecule-1 expression on SHR endothelial cells to a greater extent than on WKY endothelial cells. The findings that intercellular adhesion molecule-1 can be up-regulated to a greater degree on SHR endothelial cells may have important implications for in vivo perivascular leukocyte accumulation under hypertensive conditions. These observations indicate a possible mechanism by which hypertension may predispose to the development of disorders such as atherosclerosis and stroke. KW - Endothelzelle KW - Zell-Adhäsionsmolekül Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86819 ER - TY - JOUR A1 - Yong, Liu A1 - Jacobowitz, David M. A1 - Barone, Frank A1 - McCarron, Richard A1 - Spatz, Maria A1 - Feuerstein, Giora A1 - Hallenbeck, John M. A1 - Sirén, Anna-Leena T1 - Quantitation of perivascular monocyte / macrophages around cerebral blood vessels of hypertensive and aged rats N2 - The numbers of monocytes and macrophages in the walls of cerebral blood vessels were counted on perfusion-fixed frozen brain sections (16 JLffi) of spontaneously hypertensive rats (SHR), stroke-prone SHR (SHR-SP), normotensive Wistar-Kyoto (WKY) rats, and young (16-week-old) and old (2-year-old) normotensive Sprague-Dawley rats (SD-l6w and SD-2y, respectively) using monoclonal antiborlies against rat macrophages (ED2). The staining was visualized with fluoresceinlabeled second antiborlies. The ED2-specific staining in brain sections was restricted to macrophages in a perivascular location. The number of perivascular cells per square millimeter of high-power field was significantly greater in SHR-SP (8.6 ± 2.1; n = 4) and SHR (6. 7 ± 0.9; n = 6) than in normotensive WKY (4.0 ± 0.5; n = 6; p <0.01). The number of perivascular macrophages was also greater in SD-2y (7.5 ± 2.7; n = 9) than in SD-l6w (2.9 ± 1.8; n = 8; p < 0.01). No ED2 staining was found in the resident microglia or in the endothelial cells, which were identified by double staining with rhodamine-labeled anti-factor VIII-related antigen antiborlies. The results suggest that the stroke risk factors hypertension and advanced age are associated with increased subendothelial accumulation of monocytes and macrophages. This accumulation could increase the tendency for the endothelium to convert from an anticoagulant to a procoagulant surface in response to mediators released from these subendothelial cells. KW - Willebrand-Faktor KW - immunofluorescence KW - ED2 KW - Von Willebrand factor KW - rats KW - brain Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86800 ER - TY - CHAP A1 - Schneider, Wolfgang T1 - Memory development N2 - No abstract available. KW - Pädagogik Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69331 ER - TY - JOUR A1 - Wilhelm, Gernot T1 - Kumme und *Kumar: Zur hurritischen Ortsnamenbildung N2 - no Abstract available KW - Churritisch Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86448 ER - TY - CHAP A1 - Schreibman, Martin P. A1 - Schartl, Manfred A1 - Kallman, Klaus D. A1 - Magliulo-Cepriano, Lucia T1 - Molecular approaches to study the genetic regulation of the fish reproductive system N2 - No abstract available. KW - Fische Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86679 ER - TY - JOUR A1 - Xu, Shanjia A1 - Sheng, Xinqing A1 - Greiner, P. A1 - Becker, Charles R. A1 - Geick, R. T1 - High-order finite-element analysis of scattering properties of II-VI semiconductor materials N2 - The sattering characteristics ot the n-VI semiconductors were analyzed by a method which combines the second-order finite-element method with the rigorous mode matching procedure. The method avolds the difficulty of solving the complex transcendental equation introduced in the multimode network method and calculates all the eigenvalues and eigenfunctions simultaneously which are needed for the mode matching treatment in the longitudinal direction. As a result, the whole solution procedure is significantly simplified. A comparison is given between the experimental data and the calculated results obtained with this analysis and tbe network method. Very good agreement has been achieved, the accuracy and efficiency of the present method are thus verified. KW - Halbleiter KW - II-VI semiconductor KW - scattering characteristics KW - high-order finite element KW - mode matching method Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86283 ER - TY - JOUR A1 - Ulrichs, Karin A1 - Eckstein, V. A1 - Tibell, A. A1 - Groth, C. G. A1 - Korsgren, O. A1 - Müller-Ruchholtz, W. A1 - Thiede, A. T1 - Natürliche und induzierte xenoreaktive Antikörper vor und nach klinischer Transplantation fötaler porziner Pankreasinselzellen N2 - No abstract available. KW - Antikörper KW - Langerhans-Inseln KW - Schwein KW - Transplantation Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-72967 ER - TY - JOUR A1 - Krämer-Neubert, Sabine T1 - Hessen-Nassauisches Volkswörterbuch N2 - Unter Förderung durch den Hessischen Kultusminister aus den für ein Hessen-Nassauisches Wörterbuch mit Hilfe aller Volkskreise und besonders der Lehrerschaft unseres Arbeitsbereiches von Ferdinand Wrede angelegten und verwalteten Sammlungen ausgewählt und bearbeitet von Luise Berhold und Hans Friebertshäuser; ab Lieferung 38: Mitarbeit Heinrich J. Dingeldein. Bd. IV, Bogen 1-32 (Lieferungen 31-38 des Gesamtwerks). "Taa-Wanst" Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-86011 ER - TY - CHAP A1 - Altschmied, Joachim A1 - Schartl, Manfred T1 - Genetics and molecular biology of tumour formation in Xiphophorus N2 - No abstract available. KW - Schwertkärpfling KW - Tumor KW - Entstehung KW - Molekularbiologie KW - Genetik Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69752 ER - TY - JOUR A1 - Stopper, Helga A1 - Kirchner, S. A1 - Schiffmann, D. A1 - Poot, M. T1 - Cell cycle disturbance in relation to micronucleus formation induced by the carcinogenic estrogen diethylstilbestrol N2 - In addition to its tumor-promoting activity in honnone-receptive tissue, the carcinogenic estrogen diethylstilbestrol (DES) has been found to induce cell transformation, aneuploidy and micronucleus formation in mammalian cells. The majority of these micronuclei contained whole chromosomes and were fonned during mitosis. Here a possible relationship between a disturbance in cell cycle progression and micronucleus fonnation is investigated by exposing Syrian hamster embryo (SHE) cells to DES. Continuous bromodeoxyuridine labeling followed by bivariate Hoechst 33258/ethidium bromide flow cytometry was employed for analysis of cell cycle transit and related to the time course of micronucleus formation. Treatment of SHE cells with DES resulted in delayed and impaired cell activation (exit from the GO/G 1 phase), impaired S-phase transit and, mainly, G2-phase traverse. Cells forming micronuclei, on the other hand, were predominantly in G2 phase during DES treatment. These results suggest that impairment of Sand G2 transit may involve a process ultimately leading to micronucleus formation. KW - Toxikologie KW - Flow cytometry KW - Micronucleus formation KW - Diethylstilbestrol KW - Hoechst 33258 dye KW - Bromodeoxyuridine labeling KW - continuous Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-82250 ER - TY - JOUR A1 - Franzek, E. A1 - Stöber, Gerald A1 - Beckmann, H. T1 - Malignes neuroleptisches und lebensbedrohliches katatones Syndrom: Eine identische Komplikation im Verlauf von funktionellen Psychosen T1 - Malignant neuroleptic syndrome and lethai catatonia: an identical complication in functional psychoses N2 - no abstract available KW - Neuropsychiatrie KW - Malignes neuroleptisches Syndrom KW - akut lebensbedrohlich katatones Syndrom KW - perniziöse Katatonie KW - zykloide Psychose KW - Malignant neuroleptic syndrome KW - Iife threatening catatonic syndrome KW - lethai catatonia KW - cycloid psychosis Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-82243 ER - TY - JOUR A1 - Becker, T. A1 - Franzek, E. A1 - Jost, C. A1 - Hofmann, E. A1 - Schneider, M. A1 - Stöber, Gerald T1 - Hirnläsionen bei affektiven Erkrankungen: eine retrospektive CT-Studie T1 - Cerebral Lesions in Affective Disorders: a Retrospective CT Study N2 - 46 Patienten mit affektiven Erkrankungen und pathologischem CT wurden untersucht (Infarkt: 22, Kontusion: 6, Leukoaraiose: 11, frühkindlicher Hirnschaden: 7). Monopolar Depressive (DSMIII- R; MD) zeigten oft Leukoaraiose, Infarkte waren mit MD, Kontusionen und frühkindliche Schäden mit bipolarer Erkrankung assoziiert (BP; ANCOV A, p< .1). Kortikale Läsionen waren bei BP häufiger, jedoch fehlten signifikante Effekte von Läsionsort oder -zeitpunkt auf die Polarität der Erkrankung (ANOV A). Bei einigen Infarktpatienten kam es zur Verlaufsänderung (Chronifizierung, Bipolarität) nach Infarkt, alle Post-Infarkt-Ersterkrankungen waren bipolar. N2 - 46 patients with affective disorder and a pathologic CT scan were studied (infarct: 22, brain trauma: 6, leukoaraiosis: 11 , perinatal brain damage: 7). Unipolar depressives (DSM-I1I-R; MD) frequently had le ukoaraiosis, brain infarct was associated with unipolar depression , brain trauma and perinatal damage with bipolar illness (BP; ANCOV A , p < .1). Corticallesions were more frequ ent in BP, but ANOV A revealed no significant effect of lesion location and time of insu lt on illness polarity. In some patients with stroke course of illness changed (Ionger phases, bipolarity), first onset post-stroke went along with bipolar illness. KW - Psychiatrie KW - Klinische Psychiatrie KW - Gemeindepsychiatrie KW - organische affektive Störungen KW - Hirninfarkt KW - Kontusion KW - Frühkindlicher Hirnschaden KW - Leukoaraiose KW - Secondary affective disorder KW - Poststroke depression KW - Brain trauma KW - Perinatal brain damage KW - Leukoaraiosis Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-82237 ER - TY - JOUR A1 - Rösch, C. A1 - Hock, R. A1 - Schüssler, Ulrich A1 - Yule, P. T1 - Präislamische Schmuckperlen aus dem Oman - Erste Ergebnisse mineralogisch-materialkundlicher Untersuchungen N2 - no abstracts available KW - Schmuckperle KW - Oman Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-81822 ER - TY - JOUR A1 - Scheer, Ulrich T1 - Harold Garnet Callan 1917-1993 N2 - Professor Harold Gamet Callan, honorary member of the German Society for Cell Biology, died on the 3rd November 1993, at the age of 76. His name is inseparably connected with lampbrush chromosomes, the most spectacular and aesthetically ailuring form of chromosomes, which occupied the major part of his scientific career. " Mick" Callan's pioneering studies led to fruitful new concepts, served as a building block for many subsequent studies by others, and contributed enormously to our current understanding of chromosome organization and activity ... KW - Harold Garnet Callan Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-80789 ER - TY - CHAP A1 - Macht, Michael T1 - Kovariation und Dissoziation psychophysiologischer Variablen unter kurzzeitig verminderter Energiezufuhr N2 - no abstract available KW - Psychologie KW - Medizinische Psychologie KW - Kongress KW - Magdeburg <1994> KW - Physiologische Psychologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-80187 ER - TY - CHAP A1 - Krebs, H. A1 - Janke, W. A1 - Macht, Michael A1 - Weijers, H.-G. A1 - Weyers, P. T1 - Differentielle Tierpsychologie: Hypo- und hyperphage Reaktionen unter Streß N2 - no abstract available KW - Psychologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-80175 ER - TY - JOUR A1 - Stöber, Gerald T1 - Schwangerschaftsinfektionen bei Müttern von chronisch Schizophrenen: die Bedeutung einer differenzierten Nosologie N2 - In einer retrospektiven Untersuchung erinnerten 16 von 80 Müttern von chronisch Schizophrenen eine schwere Infektionserkrankung in der Schwangerschaft. Im zweiten Trimenon waren gehäuft Infektionen aufgetreten. Zehn von 80 Müttern von Kontrollpersonen erinnerten ebenfalls eine Infektion. Im Vergleich zu den Kontrollen halfen Mütter Schizophrener im 5. Schwangerschaftsmonat häufiger Infektionen als in den anderen Gestationsmonaten (p < 0,05). Bei "familiären" und "sporadischen" Schizophrenen gemäß DSM III-R kamen im Vergleich zu Kontrollen Infektionen in gleicher Häufigkeit vor. Wurden hingegen in der Diagnostik schizophrener Psychosen die Definitionen von Leonhard zugrunde gelegt, ergaben sich signifikante Unterschiede! Bei den systematischen Schizophrenen (denen nach Leonhard keine erbliche Disposition zugrunde liegt) waren Infektionen gehäuft im 2. Schwangerschaftsdrittel aufgetreten, sowohl im Vergleich zu Kontrollen (p < 0,01) als auch im Vergleich zu den unsystematischen Schizophrenen, die hauptsächlich genetisch bedingt zu sein scheinen (p < 0,001). Infektionserkrankungen im 5. Schwangerschaftsmonat waren ausschließlich bei den Müttern von systematischen Schizophrenen vorgekommen. Bei diesen Krankheitsformen scheinen Infektionen im 2. Schwangerschaftstrimenon und insbesondere im 5. Schwangerschaftsmonat wichtige ätiologische Faktoren zu sein und könnten mitursächlich sein für die beschriebenen zytoarchitektonischen Aberrationen im Zentralnervensystem von chronisch Schizophrenen. N2 - In a retrospective study, 16 of 80 mothers of chronic DSM III-R schizophrenics reported having had a serious infectious disease during pregnancy. Eleven of the infections had occurred during the second trimester. Influenza and the common cold with fever were frequent. Ten of 80 female controls also recalled having had an infectious illness during pregnancy. Compared to the controls, mothers of schizophrenics reported more infectious illness during pregnancy, particularly during the fifth month ofgestation (p < 0.05). Mothers of familial and of sporadic DSM III-R schizophrenics reported equal frequencies of infections in pregnancy. In contrast, when Leonhard's classification of psychoses was applied, significant differences appeared. Infections during pregnancy were scarcely found in unsystematic schizophrenics (mainly genetically determined according to Leonhard). In systematicschizophrenics (mainly exogenously determined according to Leonhard), a significantly higher frequency of infectious diseases was reported for the second trimester as compared both to controls (p < 0.01) and to unsystematic schizophrenics (p < 0.001). Infections during the fifth month of gestation were exclusively reported in systematic schizophrenics. Thus, in the systematic forms of schizophrenia infections during the second trimester and particularly during the fifth montb ofgestation seem to play an important role in the etiology and seem to be of causal importance for the various cytoarchitectural abnormalities detected in the central nervous system of schizophrenics. KW - Medizin KW - Psychologie KW - Schizophrenie KW - Schwangerschaftsinfektion KW - "Familiär-sporadisch"- Konzept KW - Leonhard-Klassifikation KW - Schizophrenia KW - Maternal infections KW - Pregnancy KW - Familial/sporadic concept KW - Leonhard classification Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-78438 ER - TY - JOUR A1 - Becker, T. A1 - Schmidtke, A. A1 - Stöber, Gerald A1 - Franzek, E. A1 - Teichmann, E. A1 - Hofmann, E. T1 - Hyperintense Marklagerläsionen bei psychiatrischen Patienten: räumliche Verteilung und psychopathologische Symptome T1 - Hyperintense white matter lesions in psychiatrie patients: spatial distribution and psychopathological symptoms N2 - In einem Kollektiv von 130 MR-tomographisch untersuchten psychiatrischen Patienten (axiale T2-SE-Sequenz) wurden Zahl und räumliche Verteilung von hyperintensen Marklagerläsionen ("white matter lesions"; WM L) erfaßt und die Ventricle-to-brain-Ratio (VBR) bestimmt. Eine Konfigurationsfrequenzanalyse auf der Grundlage der räumlichen WMLVerteilung erlaubte die Abgrenzung von vier Patientengruppen: 1. keine WML (n = 35), 2. WML rechts frontotemporal (n = 23), 3. WML bifrontal (n = 12), 4. WML ubiquitär (n = 16). Die während 3 Jahren beobachteten psychopathologischen Symptome dieser Patienten wurden retrospektiv nach dem AMDP-Systemdokumentiert. In der Gruppe mit ubiquitären WML überwogen organisch-psychopathologische Ttems, die VER war größer als in den anderen Gruppen (ANOVA;p < 0,001). Die räumliche W M L- Verteilung erklärte 10,24 % der Gesamtvarianz psychopathologischer M erkmalsverteilung in den Gruppen. Das Patientenalter (MANCOVA; p < 0,021), nicht aber die VER hattesignifikanten Einfluß auf das psychopathologische Symptomprofil. Nach Ausblendung der Patientengruppe mit ubiquitären WMLblieb der Einfluß der WML-Verteilung auf die psychopathologische Symptomatiksignifikantc (p <0,05). Bifrontale WML waren mit Denkstörung, rechts frontotemporale WML mit affektiven Symptomen assoziiert. Die Befunde sprechen für einen Einfluß der räumlichen Verteilung unspezifischer Marklagerläsionen auf die psychopathologische Symptomatik. N2 - In a sampie of 130 patients who had undergone MRI (transverse TIweighted SE sequenee) patchywhite matter lesions (WML) were documented according to number and spatial distribution in the brain. Ventricle-to-Brain Ratio (VBR) was determined. Configural frequency analysis led to delineation of four patient groups on the basis of WML 10-cation: 1. no WML (n = 35), 2. right frontal-temporal WML (n = 23), 3. bifrontal WML (n = 12),4. WML in all/all but one brain region (n = 16). Psychopathological symptoms reported in the course of a maximum of 3 years were documen ted by chart review. In the 'pervasive WML' group psychopathological items characteristic of organic brain syndromes prevailed, mean VER exceeded values in all other groups (ANOVA, p < 0.001). WML spatial distribution accounted for 10.2 % oftotal psychopathological variance. Patient age, but not VER, had a significant impact on symptom profile (MANCOVA). When the 'pervasive WML' group was excluded, the finding of a significant effect of WML location on psychopathological symptom profiles was robust. Bifrontal WML were associated with thought incoherence, right frontal-temporal WML with affective symptoms. Findings support an impact of spatial distribution of unspecific WML on psychopathological symptoms in psychiatrie patients. KW - Medizin KW - Psychopathologie KW - MRT KW - Demyelinisierung KW - Periventrikuläre Hyperintensitäten KW - Hyperintense Marklagerläsionen KW - MRI KW - Demyelination KW - Periventricular hyperintensities KW - Hyperintense white matter lesions KW - Psychopathology Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-78288 ER - TY - CHAP A1 - Herbert, M. K. T1 - Analgetikaeinsatz beim geriatrischen Patienten N2 - Nicht nur bei traumatologischen, sondern auch bei vielen internistischen und neurologischen Notfällen ist der Schmerz das oder eines der Leitsymptome. Neben der Wiederherstellung und Sicherung der Vitalfunktionen ist die rasche und effiziente Schmerzlinderung eine der wichtigsten Aufgaben des Notarztes. Eine erfolgreiche analgetische Therapie verbessert zum einen die subjektive Befindlichkeit des Patienten und unterbricht zum anderen die durch starke Schmerzen initiierten und unterhaltenen sympathiko-adrenergen und metabolisch-endokrinen Streßreaktionen, mit all ihren nachteiligen Auswirkungen auf die Hämodynamik und Respiration. Letzteres ist eine wichtige, positive Wirkung einer guten analgetischen Therapie, insbesondere beim kranken geriatrischen Patienten, der in den Kompensationsmöglichkeiten einzelner Organsysteme oft deutlich eingeschränkt ist. Länger fortbestehende starke Schmerzen würden gerade bei diesen Patienten eine Einschränkung der Hämodynamik und Respiration perpetuieren. KW - Medizin KW - Geriatrie KW - Analgetika Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-78001 ER - TY - CHAP A1 - Künzler, Jan T1 - Partnerschaft und Elternschaft im Familiensystem N2 - Partnerschaft und Elternschaft waren im Begriff der Familie bislang essentiell zusammengedacht: Partnerschaft und Elternschaft, Ehe und Filiation, beschreiben exklusiv und vollständig die Prinzipien, anhand derer sich das Familienpersonal rekrutiert (vgl. Tyrell 1983, S. 363). Beides muß nicht in Familien zusammenfallen. Immer mehr Ehen bleiben dauerhaft kinderlos -immer mehr Familien kommen als Ein-Elternfamilien ohne Partnerschaft aus. Das ist die sozialstrukturelle Version einer Entkoppelung von Partnerschaft und Elternschaft. Auf der anderen Seite sind Partnerschaft und Elternschaft in der überwiegenden Zahl der Fälle immer noch in Familien "fusioniert". KW - Partnerschaft KW - Elternschaft KW - Familienkonflikt KW - Systemische Therapie KW - Kongress KW - Bielefeld <1991> Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-50795 ER - TY - JOUR A1 - Kurtz-Costes, Beth E. A1 - Schneider, Wolfgang T1 - Self-concept, attributional beliefs, and school achievement: A longitudinal analysis N2 - No abstract available KW - Psychologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62245 ER - TY - JOUR A1 - Bjorklund, David F. A1 - Schneider, Wolfgang A1 - Cassel, William S. A1 - Ashley, Elizabeth T1 - Training and Extension of a Memory Strategy: Evidence for Utilization Deficiencies in the Acquisition of an Organizational Strategy in High- and Low-IQ Children N2 - 143 9- and 10-year-oId children were classified into high- and Jow-IQ groups and given 4 different sort/recall lists (baseline, training, near [immediate] extension, far [l-week] extension) to assess training and extension of an organizational memory strategy. All children received categorized items of moderate typicality for Phases 1, 3, and 4. For Phase 2, children were assigned to either a training or control group, with half of the children in each group receiving category typical items and the others category atypical items. Levels of recall, sorting, and clustering were greater in Phase 2 for high-IQ children, for the typical lists, and for trained children. Both the high- and low-IQ children trained with typical items continued to show high levels of recall on the near extension phase. No group of subjects maintained high levels of recall after 1 week, although levels of sorting and/or clustering on the extension trials remained high for all groups of subjects except the low-IQ control children. This latter pattern (elevated sorting/clustering with low levels of recall) is an indication of a utilization deficiency, a phase in strategy development when children use a strategy but gain little or no benefit n performance. The results provide evidence for IQ, training, and material effects in the demonstration of a utilization deficiency. KW - Psychologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62234 ER - TY - JOUR A1 - Rabinowitz, Mitchell A1 - Ornstein, Peter A. A1 - Folds-Bennett, Trisha H. A1 - Schneider, Wolfgang T1 - Age-related differences in speed of processing: Unconfounding age and experience N2 - No abstract available KW - Psychologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62223 ER - TY - JOUR A1 - McCarron, R. M. A1 - Wang, L. A1 - Sirén, Anna-Leena A1 - Spatz, M. A1 - Hallenbeck, J. M. T1 - Monocyte adhesion to cerebromicrovascular endothelial cells derived from hypertensive and normotensive rats N2 - No abstract available KW - Neurobiologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62960 ER - TY - RPRT A1 - Wang, X. A1 - Sirén, Anna-Leena A1 - Liu, Y. A1 - Yue, T-L. A1 - Barone, F. C. A1 - Feuerstein, G. Z. T1 - Upregulation of intercellular adhesion molecule-1 (ICAM-1) on brain microvascular endothelial cells in rat ischemic cortex [Research Report] N2 - The expression of intercellular adhesion molecule 1 (ICAM-1) was studied in rat focal ischemic cortex. A significant increase in ICAM-1 mRNA expression in the ischemic cortex over Ievels in contralateral (nonischemic) site was observed by means of Northern blot analysis following either permanent or temporary occlusion with reperfusion of the middle cerebral artery (PMCAO or MCAO with reperfusion) in spontaneously hypertensive rats. In the ischemic cortex, Ievels of ICAM-1 mRNA increased significantly at 3 h (2.6-fold, n = 3, P < 0.05), peaked at 6 to 12 h (6.0-fold, P < 0.01) and remained elevated up to 5 days (2.5-fold, P < 0.05) after PMCAO. The profile of ICAM-1 mRNA expression in the ischemic cortex following MCAO with reperfusion was similar to that following PMCAO, except that ICAM-1 mRNA was significantly increased as early as 1 h (6.3-fold, n = 3, P < 0.05) and then gradually reached a peak at 12 h (12-fold, P < 0.01) after reperfusion. ICAM-1 mRNA expression in ischemic cortex following PMCAO was significantly greater in hypertensive rats than in two normotensive rat strains. Immunostaining using anti-ICAM-1 antiborlies indicated that upregulated ICAM-1 expressionwas localized to endotheIial cells of intraparenchymal blood vessels in the ischemic but not contralateral cortex. The data suggest that an upregulation of ICAM-1 mRNA and protein on brain capillary endothelium may play an important rote in leukocyte migration into ischemic brain tissue. KW - Neurobiologie KW - Intercellular adhesion molecule 1 KW - Focal brain ischemia KW - Stroke KW - Reperfusion KW - lnflammation Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62952 ER - TY - RPRT A1 - McCarron, R. M. A1 - Doron, D. A. A1 - Sirén, Anna-Leena A1 - Feuerstein, G. Z. A1 - Heldman, E. A1 - Pollard, H. B. A1 - Spatz, M. A1 - Hallenbeck, J. M. T1 - Agonist-stimulated release of von Willebrand factor and procoagulant factor VIII in rats with and without risk factors for stroke [Research Report] N2 - Lipopolysaccharidc (LPS)-induced (i.v. or i.c.v., 1.8 mg/kg) release of von Willebrand factor (vWF) ·was examined in spontaneously hypertensive (SHR) and normotensive Wistar-Kyoto (WKY) rats. SHR rats releascd significantly (P < 0.05) more vWF than WKY rats in response to LPS. LPS also inhibited factor VIII procoagulant activity (FVIII: c) which may indicate an increase in thrombin activity. Cultured cerebrovascular endothelial cells (EC) derived from both SHR and WKY rats, as weil as human umbilical vein EC (HUVEC) cultures constitutively released vWF. Treatment with agonists including LPS, thrombin and tumor necrosis factor-a (TNFa) did not affect the in vitro secretion of vWF by cerebrovascular EC cultures but significantly upregulated vWF release by HUVEC cultur~s. Preincubation of cerebrovascular EC cultures with interleukin-1 OL-l) ± TNFa or co-culturing in the presence of LPS-activated syngeneic monocytes had no effect on vWF secretion. The findings demoostrate that conditions of hypertension may affect endothelial cells and make them more responsive to agonist Stimulation and thereby increase secretion of vWF, an important factqr in hemostasis as weil as thrombosis. The capacity of LPS to significantly affect the in vivo secretion of vWF in SHR and WKY rats but not cultured cerebrovascular EC indicates that observed elevations in plasma vWF were not derived from cerebrovascular EC. lt is suggested that hypertension may function as a risk factor for thrombotic stroke by influencing factors involved in coagulation processes, such as vWF and factor VIII : c. KW - Neurobiologie KW - von Willebrand factor KW - Hypertension KW - Lipopolysaccharide KW - Endothelial cell KW - Stroke KW - Monocyte Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62945 ER - TY - JOUR A1 - Stopper, Helga A1 - Eckert, I. A1 - Schiffmann, D. A1 - Spencer, D. L. A1 - Caspary, W. J. T1 - Is micronucleus induction by aneugens an early event leading to mutagenesis? N2 - This study was designed to investigate a previously unidentified potential mechanism for mutation induction as well as to clarify a biological comequence of micronucleus formation. We compared the induction of micronuclei with mutation inductioo as measured by trißuorothymidine (TFI') resistance in mouse L5178Y cells using four aneugens: colcemid, diethylstilbestrol, griseofulvin and vioblastine. AU four compounds induced micronuclei which appeared in the first cell cycle after treatment. More than 85% of the micronuclei induced by each compound stained positive for the presence of kinetochores implying that the micronuclei contained wbole cbromosomes. However, these same compounds were unable to induce TFf resistance under tbree different treatment regimes. We concluded that tbese compounds, under conditions where tbey induce primarily kinetochore positive micronuclel, were not able to induce mutations. Thus, the induction of micronuclei containing wbole chromosomes barborlog a select.able gene is not an early event leadlog to mutations in these cells. KW - Toxikologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63390 ER - TY - JOUR A1 - Stopper, Helga A1 - Kühnel, A. A1 - Podschun, B. T1 - Combination of the chemotherapeutic agent 5-fluorouracil with an inhibitor of its catabolism results in increased micronucleus induction N2 - The rate limiting step in 5-fluorouracil catabolism is catalyzed by the enzyme dihydropyrimidine dehydrogenase. Since degradation of 5-fluorouracil decreases its efficacy in chemotherapy, the inhibition of its catabolism is a promising tool. We investigated the formation of micronuclei in vitro in mouse L5178Y cells. 5-fluorouracil induced an increase in micronucleus frequency, which could significantly be enhanced by the concurrent application of 2,6-dihydroxypyridine, an inhibitor of dihydropyrimidine dehydrogenase. The 5-fluorouracil concentration necessary to reach maximal genotoxic effects could be reduced to half in the presence of inhibitor. 2,6-Dihydroxypyridine alone and the naturally occuring enzyme substrate uracil did not induce micronucleus formation. Combined application of the chemotherapeutic agent 5-fluorouracil and an inhibitor of its could reduce side-effects by lowering the effective dose of the active drug. With this study we provide further support for the usefulness of this concept. KW - Toxikologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-63383 ER - TY - JOUR A1 - Lubjuhn, T. A1 - Schartl, Manfred A1 - Epplen, J. T. T1 - Methodik und Anwendungsgebiete des genetischen Fingerabdruckverfahrens N2 - No abstract available KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61978 ER - TY - CHAP A1 - Gotz, R. A1 - Schartl, Manfred T1 - The conservation of neurotrophic factors during vertebrate evolution N2 - No abstract available KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61964 ER - TY - JOUR A1 - Schartl, A. A1 - Dimitrijevic, N. A1 - Schartl, Manfred T1 - Evolutionary origin and molecular biology of the melanoma-inducing oncogene of Xiphophorus N2 - No abstract available KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61954 ER - TY - JOUR A1 - Schneider-Schaulies, Sibylle A1 - Schneider-Schaulies, Jürgen A1 - Schuster, A. A1 - Bayer, M. A1 - Pavlovic, J. A1 - ter Meulen, V. T1 - Cell type specific MxA-mediated inhibition of measles virus transcription in human brain cells N2 - No abstract available KW - Virologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62255 ER - TY - JOUR A1 - Segev, Y. A1 - Rager-Zisman, B. A1 - Isakov, N. A1 - Schneider-Schaulies, Sibylle A1 - ter Meulen, V. A1 - Udem, S. A. A1 - Segal, S. A1 - Wolfson, M. T1 - Reversal of measles virus mediated increase of phosphorylating activity in persistently infected mouse neuroblastoma cells by anti measles antibodies N2 - No abstract available KW - Virologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62362 ER - TY - JOUR A1 - Schneider-Schaulies, Jürgen A1 - Schneider-Schaulies, S. A1 - Schuster, A. A1 - Bayer, M. A1 - Pavlovic, J. A1 - ter Meulen, V. T1 - Cell type specific MxA-mediated inhibition of measles virus transcription in human brain cells N2 - Measles virus (MV)-specific transcription in human brain cells is characterized by particularly low abundances of the distal mRNAs encoding the MV envelope proteins. Similar transcriptional restrictions of the closely related vesicular stomatitis virus have been observed in mouse fibroblasts constitutively expressing the interferon-inducible MxA protein (P. Staeheli and J. Pavlovic, J. Virol. 65:4498-4501, 1991). We found that MV infection of human brain cells is accompanied by rapid induction and high-level expression of endogenous MxA proteins. After stable transfection of MxA, human glioblastoma cells (U-87-MxA) released 50- to 100-fold less infectious virus and expression of viral proteinswas highly restricted. The overall MV-specific transcription Ievels were reduced by up to 90%, accompanied by low relative frequencies of the distal MV-specific mRNAs. These restrictions were linked to an inhibition of viral RNA synthesis and not to a decreased stability of the viral RNAs. Our results indicate that expression of MxA is associated with transcriptional attenuation of MV in brain cells, thus probably contributing to the establishment of persistent MV central nervous system infections. In addition, the mechanism of MxA-dependent resistance against MV infection, in contrast to that of vesicular Stomatitis virus, is cell type specific, because an inhibition of MV glycoprotein synthesis independent of transcriptional alterations was observed in MxA-transfected human monocytes Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-34313 ER - TY - JOUR A1 - Maisner, A. A1 - Schneider-Schaulies, Jürgen A1 - Liszewski, M.K. A1 - Atkinson, J.P. A1 - Herrler, G. T1 - Binding of measles virus to membrane cofactor protein (CD46): importance of disulfide bonds and N-glycans for the receptor function N2 - Two cellular proteins, membrane cofactor protein (MCP) and moesin, were reported recently to be functionally associated with the initiation of a measles virus infection. We bave analyzed the interaction of measles virus with cell surface proteins, using an overlay binding assay with cellular proteins immobilized on nitrocellulose. Among surface-biotinylated proteins from a human rectal tumor cellline (HRT), measles virus, was able to bind only to a 67-kDa proteinthat was identified as MCP. The virus recognized dift'erent isoforms of MCP expressed from human (HRT and HeLa) and simian (Vero) celllines. The binding of measles virus to MCP was abolished after cleavage of the disulfide bonds by reducing agents as weil as after enzymatic release of N-linked oligosaccharides. By contrast, removal of sialic acid or 0-linked oligosaccharides did not aft'ect the recognition of MCP by measles virus. These data indicate that the receptor determinant of MCP is dependent on a conformation of the protein that is maintained by disulfide bonds and N-glycans present in tbe complement binding domains. Our results are consistent with a roJe of MCP as primary attacbment site for measles virus in the initial stage of an infection. The functional relationship between MCP and moesin in a measles virus infection is discussed. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-34324 ER - TY - JOUR A1 - Schneider-Schaulies, Sibylle A1 - Schnorr, J.-J. A1 - Dunster, L. M. A1 - Schneider-Schaulies, Jürgen A1 - ter Meulen, Volker T1 - The role of host factors in measles virus persistence N2 - As critical steps in the life cycle oJ measles virus (Mfl), the e.fficiency of uptake into and replication in susceptible host cells are governed by cellular determinants. Measles virus infections of cells of the human CNS are characterized by particular constraints imposed on v1:ral transcription and translation attenuating viral gene Junctions and thus contributing to the pathogenesis oJ MV persistence in these cells. KW - Immunologie KW - CNS infection KW - MV receptor KW - MV transcription KW - unwindase Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-54944 ER - TY - JOUR A1 - Dunster, L.M. A1 - Schneider-Schaulies, Jürgen A1 - Löffler, S. A1 - Lankes, W. A1 - Schwartz-Albiez, R. A1 - Lottspeich, F. A1 - ter Meulen, V. T1 - Moesin: a cell membrane protein linked with susceptibility to measles virus infection N2 - Measles virus is a highly contagious virus causing acute and persistent diseases in man, the receptor of which is still not weil characterized. We have isolated a monoclonal antibody (mAb), designated mAb 119, which specifically inhibits measles virus infection of susceptible celllines in a dosa-dependent manner. This antibody precipitates a protein with an apparent molecular mass of 75 kDa from 1251 surface-labeled cells and its epitope is present on human peripheral blood mononuclear cells, human celllines, and the African green monkey cellline Vero. Affinity chromatography of detergent-solubilized cell membrane proteins over a Sepharose column with covalently bound mAb 119 led to the partial purification of the 75-kOa protein. Preincubation of measles virus with this affinity-purified protein inhibited measles virus infection dose dependently. Aminoacid microseq,uencing of this protein revealed its identity with the human membrane-organizing extension spike protein moesin, a protein intra- and extracellularly associated with the plasma membrane of cells. Subsequently, an antibody raised against purified moesin (mAb 38/87) was also found to specifically inhibit measles virus infection of susceptible cells and confirmed our data obtained with mAb 119. Our data suggest that moesin is acting as a receptor for measles virus. KW - Immunologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-54931 ER - TY - JOUR A1 - Probstmeier, R. A1 - Bilz, A. A1 - Schneider-Schaulies, Jürger T1 - Expression of the neural cell adhesion molecule and polysialic acid during early mouse embryogenesis N2 - The expression of the neural cell adhesion molccule (N-CAM) and a 2-8 linked polysialic acid (PSA), whieh is believed to be predominantly expressed on N-CAM, was investigated during early embryonie development ofthe mouse (embryonic days 7.5 to 10.0). By immunoeytoehemistry, in tissue sections, N-CAM and PSA were not detectable at embryonie day 7.5 but were expressed in the prominent body regions such as somites, unsegmented mesoderm, developing heart, and neuroectoderm at embryonie day 8.0 N-CAM and PSA immunoreaetivities were always predominantly associated with tbe plasma membrane. No tissue could be detected which was positive for PSA but negative for N-CAM. In Western blot analysis of whole embryos, by contrast, only the lightly sialylated and PSA-negative 180 and 140 kD isoforms of N-CAM werc present at embryonie day 8.0 and strong expression of PSA-bearing, heavily sialylated N-CAM was not detectable before embryonie day 10.0. In Western blot analysis of N-CAM immunoaffinity purifled from whole embryos and digested with neuraminidase as weil as in Northern blot analysis, the 120 kD isoform of N-CAM or its eorresponding mRN A were not expressed in detectable amounts during the time period investigated. KW - Immunologie KW - embryo KW - mouse KW - N-CAM KW - sialic acid Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-54921 ER - TY - BOOK ED - Mälzer, Gottfried ED - Baumann, Brigitte T1 - Würzburger Hochschulschriften : 1804 - 1885 ; Bestandsverzeichnis N2 - Die Universitätsbibliothek Würzburg hat für ihre umfangreiche Sammlung alter Würzburger Hochschulschriften einen Katalog erarbeitet, der hauptsächlich Dissertationen und Thesen verzeichnet, aber auch andere Prüfungsarbeiten, die für den Erwerb unterschiedlicher akademischer Grade und Titel ausgearbeitet und publiziert worden sind. Dies ist der 2. Band der Nachweise für die Jahre 1804 bis 1885 mit 2510 Titeln. KW - Universität KW - Universitätsbibliothek KW - Hochschulschrift KW - Würzburg KW - Verzeichnis KW - 19. Jahrhundert KW - university KW - University Library Wuerzburg KW - theses KW - catalog Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-69743 ER - TY - JOUR A1 - Müller, T. A1 - Dieckmann, T. A1 - Sebald, Walter A1 - Oschkinat, H. T1 - Aspects of receptor binding and signalling of interleukin-4 investigated by site-directed mutagenesis and NMR spectroscopy N2 - Cytokines are hormones that carry information from ceJI to ceH. This information is read from their surface upon binding to transmembrane receptors and by the subsequent initiation of receptor oligomerization. An inftuence on this process through mutagenesis on the hormone surface is highly desirab)e for medical reasons. However, an understanding of hormone-receptor interactions requires insight into the structural changes introduced by the mutations. In this line structural studies on human TL-4 and the medically important IL-4 antagonists YI24D and Y124G are presented. The site a.round YI24 is an important epitope responsible for the a.bility of 11-4 t.o ca.use a signal in the target cells. It is shown that the local main-chain structure around residue 124 in the variants remains unchanged. A strategy is presented here which allows the study of these types of proteins and their variants by NMR which does not require carbon Iabeiied sa.mples. KW - Biochemie KW - Interleukin-4 KW - protein structure KW - NMR KW - signal transduction Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62444 ER - TY - JOUR A1 - Lehrnbecher, T. A1 - Poot, M. A1 - Orscheschek, K. A1 - Sebald, Walter A1 - Feller, A. C. A1 - Merz, H. T1 - Interleukin 7 as interleukin 9 drives phytohemagglutinin-activated T cells through several cell cycles; no synergism between interleukin 7, interleukin 9 and interleukin 4 N2 - The effects of the interlenkins IL-7 and IL-9 on cell cycle progression were investigated by conventional [3H]thymidine incorporation and by the bivariate BrdU/Hoechst technique. 8oth IL· 7 and IL-9 drive phytohemagglutinin-activated T cells through more than one cell cycle, but IL-7 wasmorepotent on cell cycle progression than IL-9. Neither synergistic nor inhibitory effects were seen between various combinations of the lymphokines IL-7, IL-9 and IL-4 compared to each lymphokine alone. When T cells are activated with phytohemagglutinin for 3 days, all or most IL-4 responsive cells respond to IL-7 as weil, whereas only a part of IL-7 responders are IL-4 responders. In contrast, when T cells are activated with phytohemagglutinin for 7 days, the quantitative data of the cell cycle distribution soggest that the population of IL-7 responders is at least an overlapping, if not a real subset of the population of the IL-4 responders. KW - Biochemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62438 ER - TY - JOUR A1 - Demchuk, E. A1 - Mueller, T. A1 - Oschkinat, H. A1 - Sebald, Walter A1 - Wade, R. C. T1 - Receptor binding properties of four-helix-bundle growth factors deduced from electrostatic analysis N2 - Hormones of the hematopoietin class mediate signal transduction by binding to specific transmembrane receptors. Structural data show that the human growth hormone (hGH) forms a complex with a homodimeric receptor and that hGH is a member of a class of hematopoietins possessing an antiparallel 4-a-helix bundle fold. Mutagenesis experiments suggest that electrostatic interactions may have an important influence on hormonereceptor recognition. In order to examine the specificity of hormone-receptor complexation, an analysis was made of the electrostatic potentials of hGH, interleukin-2 (IL-2), interleukin-4 (IL-4), granulocyte colony-stimulating factor (G-CSF), granulocyte-macrophage colony-stimulating factor (GM-CSF), and the hGH and IL-4 receptors. The binding surfaces of hGH and its receptor, and of IL-4 and its receptor, show complementary electrostatic potentials. The potentials of the hGH and its receptor display approximately 2-fold rotational symmetry because the receptor subunits are identical. In contrast, the potentials of GM-CSF and IL-2 Iack such symmetry, consistent with their known high affinity for hetero-oligomeric receptors. Analysis of the electrostatic potentials supports a recently proposed hetero-oligomeric model for a high-affinity IL-4 receptor and suggests a possible new receptor binding mode for G-CSF; it also provides valuable information for guiding structural and mutagenesis studies of signal-transducing proteins and their receptors. KW - Biochemie KW - cytokines KW - electrostatic potential KW - hematopoietic receptors KW - human growth factor KW - interleukins KW - molecular recognition Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62424 ER - TY - JOUR A1 - Reusch, P. A1 - Arnold, S. A1 - Heusser, C. A1 - Wagner, K. A1 - Weston, B. A1 - Sebald, Walter T1 - Neutralizing monoclonal antibodies define two different functional sites in human interleukin-4 N2 - Human interleukin-4 (IL-4) is a small four-helix-bundle protein which is essential for organizing defense reactions against macroparasites, in particular helminths. Human IL-4 also appears to exert a pathophysiological role during various IgE-mediated allergic diseases. Seven different monoclonal antibodies neutralizing the activity of human IL-4 were studied in order to identify functionally important epitopes. A collection of 41 purified IL-4 variants was used to analyse how defined amino acid replacements affect binding affinity for each individual mAb. Specific amino acid positions could be assigned to four different epitopes. mAbs recognizing epitopes on helix A and/or C interfered with IL-4 receptor binding and thus inhibited IL-4 function. However, other mAbs also inhibiting IL-4 function recognized an epitope on helix D of IL-4 and did not inhibit IL-4 binding to the receptor protein. One mAb, recognizing N-terminal and C-terminal residues, partially competed for binding to the receptor. The results of these mAb epitope analyses confirm and extend previous data on the functional consequences of the amino acid replacements which showed that amino acid residues in helices A and C of IL-4 provide a binding site for the cloned IL-4 receptor and that a signalling site in helix D interacts with a further receptor protein. KW - Biochemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62418 ER - TY - JOUR A1 - Müller, T. A1 - Sebald, Walter A1 - Oschkinat, H. T1 - Antagonist design through forced electrostatic mismatch N2 - No abstract available KW - Biochemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62408 ER - TY - JOUR A1 - Tony, H. P. A1 - Shen, B. J. A1 - Reusch, P. A1 - Sebald, Walter T1 - Design of human interleukin-4 antagonists inhibiting interleukin-4-dependent and interleukin-13-dependent responses in T-cells and B-cells with high efficiency N2 - Human interleukin-4 possesses two distinct sites for receptor activation. A signaHing site, comprising residues near the C-terminus on helix D, determines the efficacy of interleukin-4 signal transduction without affecting the binding to the interleukin-4 receptor a subunit. A complete antagonist and a series of low-efficacy agonist variants of human interleukin-4 could be generated by introducing combinations of two or three negatively charged aspartic acid residues in this site at positions 121, 124, and 125. One of the double variants, designated [R121D,Y124D]interleukin-4, with replacements of böth Arg121 and Tyr124 by aspartic acid residues was completely inactive in all analysed cellular responses. The loss of efficacy in [R121D,Y124D]interleukin-4 is estimated to be larger than 2000-fold. Variant [R121D,Y124D]interleukin-4 was also a perfect antagonist for inhibition of interleukin-13-dependent responses in B-cells and the TF-1 cellline with a K\(_i\) value of approximately 100 pM. In addition, inhibition of both interleukin-4-induced and interleuk.in-13- induced responses could be obtained by monoclonal antibody X2/45 raised against interleukin-4Rm the extracellular domain of the interleuk.in-4 receptor a subunit. These results indicate that efficient interleukin-4 antagonists can be designed on the basis of a sequential two-step activation model. In addition, the experiments indicate the functional participation of the interleukin-4 receptor a subunit in the interleukin-13 receptor system. KW - Biochemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62394 ER - TY - JOUR A1 - Kübler, N. A1 - Reuther, J. A1 - Kirchner, T. A1 - Pfaff, M. A1 - Müller-Hermelink, H. K. A1 - Albert, R. A1 - Sebald, Walter T1 - IgG monoclonal antibodies that inhibit osteoinductivity of human bone matrix-derived proteins (hBMP/NCP) N2 - Monoclonal hBMP/NCP (human bone morphogenetic protein anrl associaterl noncollagenous proteins) antiborlies of the lgG class were prorlucerl. In vitro, 12 of 19 hBMP/NCP antiborlies showerl functional inhibition of hBMP/ NCP-induced chondroneogenesis in a neonatal muscle tissue assay. Inducing factors were characterized by their inhibiting antibodies with immunoblotting. Several peptide factors seem to be involved in the cascade of inducerl chondro- and osteogenesis. KW - Biochemie KW - bone morphogenetic proteins KW - neutralizing antibodies KW - cartilage induction Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-62388 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. T1 - Bis[benzilato(2-)-O\(^1\),O\(^2\)][2-(dimethylammonio)ethoxy]silicate: synthesis and structural characterization of a zwitterionic \(\lambda^5\)Si-silicate with a SiO\(_5\) framework N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64400 ER - TY - JOUR A1 - Mühleisen, M. A1 - Tacke, Reinhold T1 - meso-[1,4-Piperaziniumdiylbis(methylene)]bis{bis[2-methyllactato(2-)-O1,O2]silicate} octahydrate: synthesis and crystal structure analysis of a zwitterionic dispirocyclic \(\lambda^5\)Si,\(\lambda^5\)Si'-disilicate N2 - The zwitterionic dispirocyclic \(\lambda^5\)Si,\(\lambda^5\)Si'-disilicate meso-[1 ,4-piperaziniumdiylbis( methylene)]bis{ bis[ 2-methyllactato(2-)-O\(^1\),O\(^2\)]silicate} octahydrate (6-8H\(_2\)O) was synthesized by reaction of 1,4-bis[(trimethoxysilyl}methyl] piperazine (8) with 2-methyllactic acid (molar ratio 1:4) in water/acetone (yield 82%). The molecular dinuclear silicon(IV) complex 6 contains two pentacoordinate (formally negatively charged) silicon atoms and two tetracoordinate (formally positively charged) nitrogen atoms. The crystal structure of 6•8H20 was studied by X-ray diffraction. KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64396 ER - TY - JOUR A1 - Mühleisen, M. A1 - Tacke, Reinhold T1 - Twofold deprotonated citric acid as a bidentate ligand of pentacoordinate silicon: synthesis and structural characterization of the zwitterionic \(\lambda_5\)Si-spirosilicate bis[citrato(2-)-O\(^3\),O\(^4\)][(dimethylammonio)methyl]silicate hydrate N2 - The zwitterionic \(\lambda_5\) Si-spirosilicate bis[ citrato(2-)-0\(^3\) ,0\(^4\) )[ ( dimethylammonio) methyl]silicate (4) was synthesized by reaction of (MeO)\(_3\)SiCH\(_2\)NMe\(_2\) (3) with citric acid (molar ratio 1 :2) in acetonitrile at room temperature and isolated, after crystallization from water, as the hydrate 4 · H\(_2\)O (yield 81 %). The crystal structure of 4 · H\(_2\)O was studied by single-crystal X-ray diffraction. The alcoxide oxygen atoms and central carboxylate oxygen atoms of two citrato(2-) ligands and one carbon atom coordinate to the silicon atom of 4 · H\(_2\)O. The coordination polyhedron around the pentacoordinate silicon atom (SiO\(_4\)C framework) can be described as a distorted trigonal bipyramid, the two carboxylate oxygen atoms occupying the axial sites. The \(\lambda_5\) Si~silicon(IV) complex 4 also exists in solution (DMSO, H\(_2\)O). KW - Anorganische Chemie KW - Silicon KW - pentacoordinate KW - Lambda5Si-Spirosilicate KW - zwitterionic KW - Citrato(2-)-03 KW - 04ligand Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64388 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. T1 - Hexacoordinate silicon in a compound with an F\(_5\)SiC unit N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64378 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. T1 - Hexakoordiniertes Silicium in einer molekularen Verbindung mit einer F\(_5\)SiC-Einheit N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64365 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. A1 - Jones, P. G. T1 - The first zwitterionic, optically active disilicate with pentacoordinate silicon N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64358 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Mühleisen, M. A1 - Jones, P. G. T1 - Das erste zwitterionische, optisch aktive Disilicat mit pentakoordiniertem Silicium N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64343 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Lopez-Mras, A. A1 - Jones, P. G. T1 - Syntheses, crystal structure analyses, and NMR studies of [2-(dimethylammonio)phenyl]bis[glycolato(2-)-O1,O2]silicate and related zwitterionic spirocyclic \(\lambda_5\)Si-silicates N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64339 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Sperlich, J. A1 - Becker, B. T1 - Bis[2,3-naphthalenediolato(2-)](pyrrolidinio-methyl)germanate-tetartoacetonitrile, the first zwitterionic \(\lambda_5\)-germanate: synthesis and crystal structure analysis N2 - The zwitterionic spirocyclic \(\lambda_5\)-germanate bis(2,3-naphthalenediolato( 2-)](pyrrolidiniomethyl)germanate (8) was synthesized and the crystal structure of its tetartoacetonitrile solvate 8 · 1/4 CH\(_3\)CN studied by single-crystal X-ray diffraction. Compound 8 was prepared by reaction of (MeO)\(_3\)GeCH\(_2\)NC\(_4\)H\(_8\) (11; NC\(_4\)H\(_8\) = pyrrolidino) with two equivalents of 2,3-naphthalenediol (isolated as 8 · 1/4 CH\(_3\)CN; yield 92%). The coordination polyhedron around the pentacoordi- naphthalenediolatonate germanium atom of 8 · 1/4 CH\(_3\)CN can be described as a strongly distorted trigonal bipyramid (the structure is displaced by 38.9% from the ideal trigonal bipyrarnid towards the ideal square pyramid), the carbon atom occupying an equatorial position. In the crystal lattice of 8 · 1/4 CH\(_3\)CN, the zwitterions form intermolecular N-H ... o hydrogen bonds leading to the formation of dimers. 1H- and \(^{13}\C-NMR studies revealed that 8 also exists in solution ([D\(_6\)]DMSO). KW - Anorganische Chemie KW - Lambda5-Germanate KW - zwitterionic KW - Germanium KW - pentacoordinate Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64329 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Wagner, S. A. A1 - Sperlich, J. T1 - Synthese von (-)-(Acetoxymethyl)(hydroxy-methyl)methyl(phenyl)german [(-)-MePhGe(CH\(_2\)OAc)(CH\(_2\)OH)] durch eine Esterase-katalysierte Umesterung: Die erste enzymatische Synthese eines optisch aktiven Germans N2 - No abstract available. KW - Anorganische Chemie KW - Germane KW - optically active KW - Biotransformation KW - stereoselective Transesterification KW - enzymatic KW - Porcine liver esterase Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64310 ER - TY - JOUR A1 - Tacke, Reinhold A1 - Pikies, J. A1 - Wiesenberger, F. A1 - Ernst, L. A1 - Schomburg, D. A1 - Waelbroeck, M. A1 - Christophe, J. A1 - Lambrecht, G. A1 - Gross, J. A1 - Mutschler, E. T1 - Sila-biperiden und endo-Sila-biperiden: Synthesen, Kristallstrukturen und antimuscarinische Eigenschaften N2 - Starting from trichloro(vinyl)silane (Cl\(_3\)SiCH=CH\(_2\)), the musearinic antagonists sila-biperiden [rac-(SiRS,C2SR>-ao-2] and endosila- biperiden [rac-(SiRS,C2SR)-endo-2] were prepared by a seven-step synthesis. Both silanols are configurationally stableininert organic solvents but undergo slow epimerization in aqueous solution (pH 7.4, 32°C) by inversion of the configuration at the silicon atom. The relative configurations of sila-biperiden and endo-sila-biperiden were detennined by single-crystal X-ray diffraction. Both compounds form intennolecular 0-H · · · N hydrogen bonds in the crystal leading to the fonnation of centrosymmetric dimers (sila-biperiden) and infinite chains (endo-sila-biperiden), respectively. Sila-biperiden is a silicon analogue (C/Si exchange) of the antiparkinsonian drug biperiden [rac-(CRS/C2SR}-exo-1]. In functional phannacological experiments, as well as in radioligand competition studies, biperiden, sila-biperiden and endo-sila-biperiden behaved as simple competitive antagonists at muscarinic Ml-, M2-, M3- and M4-receptors. The three compounds displayed the highest affinity for Ml-receptors (pA\(_2\) values: 8.72-8.80; pK\(_i\) values: 8.8-9.1), intermediate affinity for M4- and M3-receptors, and lowest affinity for M2-receptors (pA\(_2\) values: 7.57-7.79; pK\(_i\) values: 7.7-7.8). The affinity profile (Ml >. M4 > M3 > M2) of biperiden, sila-biperiden and endo-sila-biperiden is qualitatively similar to that of the M1-selective muscarinic antagonist pirenzepine. The antimuscarinic properlies of the C/Si analogues biperiden and sila-biperiden are almost identical. N2 - Die Antimuscarinica Sila-biperiden [rac-(SiRS,C2SR)-exo-2] und endo-Sila-biperiden [rac-(SiRS,C2SR)-endo-2] wurden ausgehend von Trichlor(vinyl)silan (Cl\(_3\)SiCH=CH\(_2\)) durch eine siebenstufige Synthese dargestellt. Die beiden Silanoie sind in inerten organischen Solvenzien konfigurationsstabil, unterliegen aber in wässeriger Lösung (pH 7.4, 3ZOC) einer Epimerisierung durch Inversion der Konfiguration am Silicium-Atom. Die relativen Konfigurationen von Sila-biperiden und endo-Sila-biperiden wurden durch Einkristall-Röntgenstrukturanalysen bestimmt. Beide Verbindungen bilden im Kristall intermolekulare 0-H · · · N-Wasserstoff- Brückenbindungen aus, die zum Aufbau von zentrosymmetrischen Dimeren (Sila-biperiden) bzw. unendlichen Ketten (endo-Sila-biperiden) führen. Sila-biperiden ist ein Silicium-Analogon (C/Si-Austausch) des Antiparkinsonmittels Biperiden [rac-(CRS,C2SR>-ao-1). Sowohl in funktionellen pharmakologischen Untersuchungen als auch in Radioligand-Kompetitionsexperimenten erwiesen sich Biperiden, Sila-biperiden und endo-Sila-biperiden als rein kompetitive Antagonisten an muscarinischen M1-, M2-, M3- und M4-Rezeptoren. Alle drei Verbindungen zeigten die höchste Affinität zu den Mt-Rezeptoren (pA\(_2\)-Werte: 8.72-8.80; pKrWerte: 8.8-9.1), eine deutlich geringere Affinität zu den M4- und M3-Rezeptoren und die niedrigste Affinität zu den kardialen M2-Rezeptoren (pA\(_2\)-Werte: 7.57-7.79; pKi-Werte: 7.7-7.8). Das Affinitätsprofil (Ml > M4 > M3 > M2) von Biperiden, Sila-biperiden und endo-Sila-biperiden ist dem des Mt-selektiven Antimuscarinicums Pirenzepin qualitativ sehr ähnlich. Die antimuscarinischen Eigenschaften der C/Si-Analoga Biperiden und Sila-biperiden sind nahezu identisch. KW - Anorganische Chemie KW - Silicon KW - Silanol KW - Sila-biperiden KW - Bioorganosilicon chemistry KW - Muscarinic antagonist KW - Muscarinic receptor subtype Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-64303 ER - TY - JOUR A1 - Kaupp, Martin A1 - Dolg, Michael A1 - Stoll, Hermann A1 - Schnering, Hans Georg von T1 - Oxidation State +IV in Group 12 Chemistry : Ab Initio Study of Zinc(IV), Cadmium(IV), and Mercury(IV) Fluorides N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60018 ER - TY - JOUR A1 - Wissing, Elmo A1 - Kaupp, Martin A1 - Boersma, Jaap A1 - Spek, Anthony L. A1 - Koten, Gerard van T1 - Alkylation Reactions of Dialkylzinc Compounds with 1,4- Diaza- 1,3-butadienes: Cationic and radical Anionic Organozinc Intermediates. Molecular Structure of the Cationic Organozinc Species [MeZn(t-BuN=CHCH=N-t-Bu)]O\(_3\)SCF\(_3\) and Me\(_2\)Zn(bpy)(bpy = 2,2' -Bipyridine) N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60008 ER - TY - JOUR A1 - Kaupp, Martin A1 - Schnering, Hans Georg von T1 - The Dominance of Linear 2-Coordination in Mercury Chemistry: Quasirelativistic and Nonrelativistic ab Initio Pseudopotential Study of (HgX\(_2\))\(_2\) (X=F, Cl, Br, I, H) N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59995 ER - TY - JOUR A1 - Kaupp, Martin A1 - Schnering, Hans Georg von T1 - Origin of the Unique Stability of Condensed-Phase Hg\(_2 ^{2+}\). An ab Initio Investigation of M\(^I\) and M\(^{II}\) Species (M= Zn, Cd, Hg) N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59981 ER - TY - JOUR A1 - Grunicke, H. A1 - Pyerin, W. A1 - Eisenbrand, G. A1 - Havemann, K. A1 - Rabes, H. M. A1 - Molling, K. A1 - Schwab, M. A1 - Lutz, Werner K. A1 - Wahrendorf, J. A1 - Schirrmacher, V. T1 - 7th International Symposium of the Division of Experimental Cancer Research (AEK) of the German Cancer Society : [Meeting report] N2 - No abstract available KW - Toxikologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60651 ER - TY - JOUR A1 - Fischer, W. H. A1 - Lutz, Werner K. T1 - Short communication : Mouse skin papilloma formation by chronic dermal application of 7,12-dimethylbenz[a]anthracene is not reduced by diet restriction N2 - No abstract available KW - Toxikologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60644 ER - TY - JOUR A1 - Shephard, S. E. A1 - Lutz, Werner K. A1 - Schlatter, C. T1 - The lacI transgenic mouse mutagenicity assay: quantitative evaluation in comparison to tests for carcinogenicity and cytogenetic damage in vivo N2 - The detection Iimit of the lacl transgenic mouse mutagenicity assay lies, in practice, at approximately a 50-100% increase in mutant frequency in treated animals over controls. The sensitivity of this assay in detecting genotoxins can be markedly improved by subchronic rather than acute application of the test compound. The lac/ transgenic mouse mutagenicity assay was compared quantitatively to rodent carcinogenicity tests and to presently used in vivo mutagenicity assays. With the genotoxic carcinogens tested thus far, a rough correlation between mutagenic potency and carcinogenic potency was observed: on average, to obtain a doubling in lacl mutant frequency the mice bad to be treated with a total dose equal to 50 times the TD50 daily dose Ievel. This total dose could be administered eilher at a high dose rate within a few days or, preferably, at a low dose rate over several weeks. This analysis also indicated that a lacl experiment using a 250-day exposure period would give a detection Iimit approximately equal to that of a long-term carcinogenicity study. In comparison to the micronucleus test or the chromosome aberration assay, acute sturlies with the presently available lacl system offered no increase in sensitivity. However, subchronic lacl sturlies (3-4-month exposure) resulted in an increase in sensitivity over the established tests by 1-2 orders of magnitude (shown with 2-acetylaminofluorene, N-nitrosomethylamine, N-nitrosomethylurea and urethane). 1t is concluded that a positive result in the lacl test can be highly predictive of carcinogenicity butthat a negative result does not provide a large margin of safety. KW - Toxikologie KW - Transgenie mice KW - Mutagenicity assay KW - Sensitivity KW - Chromosome aberration KW - Micronucleus test KW - Carcinogenic potency Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60638 ER - TY - JOUR A1 - Kaupp, Martin A1 - Schnering, Hans Georg von T1 - Ab Initio Comparision of the (MX\(_2\))\(_2\) Dimers (m=Zn, Cd, Hg; X F, Cl, H), and Study of Relativistic Effects in Crystalline HgF\(_2\) N2 - No abstract available KW - Anorganische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59971 ER - TY - JOUR A1 - Klotz, Karl-Norbert A1 - Jesaitis, A. J. T1 - The interaction of N-formyl peptide chemoattractant receptors with the membrane skeleton is energy-dependent N2 - Desensitization of N-fonnyl peptide chemoattractant receptors (FPR) in human neutrophils is thought to be achieved by lateral segregation of receptors and G proteins within the plane of the plasma membrane resulting in an interruption of the signalling cascade. Direct coupling of FPR to membrane skeletal actin appears to be the basis of this process~ however, the molecular mechanism is unknown. In this study we investigated the effect of energy depletion on formation of FPR-membrane skeleton complexes. In addition the effect of the protein kinase C inhibitor stauroporine and the phosphatase inhibitor okadaic acid on coupling of FPR to the membrane skeletonwas studied. Human neutrophils were desensitized using the photoreactive agonist N-formy1-met-leu-phe-1ys-N'[\(^{125}\)I]2(p-azidosalicylamido)ethyl-1,3'-dithiopropionate (fMLFK-[\(^{125}\)I]ASD) after ATP depletion with NaF or after incubation with the respective inhibitors. The interaction of FPR with the membrane skeleton was studied by Sedimentation of the membrane skeleton-associated receptors in sucrose density gradients. Energy depletion of the cells markedly inhibited the formation of FPR-membrane skeleton complexes. This does not appear tobe related to inhibition of protein phosphorylation due to ATP depletion because inhibition of protein kinases and phosphatases bad no significant effect on coupling of FPR to the membrane skeleton. We conclude, therefore, that coupling of FPR to the membrane skeleton is an energy,dependent process which does not appear to require modification of the receptor protein by phosphorylation. KW - Toxikologie KW - Chemotactic receptors KW - G proteins KW - N-formyl peptides KW - signal transduction KW - desensitization KW - membrane skeleton KW - receptor-G protein coupling. Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60499 ER - TY - JOUR A1 - Klotz, Karl-Norbert A1 - Jesaitis, A. J. T1 - Physical coupling of N-formyl peptide chemoattractant receptors to G protein is not affected by desensitization N2 - Desensitization of N-formyl peptide chemoattractant receptors (FPR) in human neutrophils results in association of these receptors to the membrane skeleton. This is thought to be the critical event in the lateral segregation of receptors and guanyl nucleotide-binding proteins (G proteins) within the plane of the plasma membrane resulting in an interruption of the signaling cascade. In this study we probed the interaction of FPR with G protein in human neutrophils that were desensitized to various degrees. Human neutrophils were desensitized using the photoreactive agonist N-formyl-met-leu-phelys- N\(^\epsilon\)-[\(^{125}\)I]2(p-azidosalicylamido )ethyl-1 ,3 '-dithiopropionate (/MLFK-[\(^{125}\)I]ASD). The interaction if FPR with G protein was studied via a reconstitution assay and subsequent analysis of FPR-G protein complexes in sucrose density gradients. FPR-G protein complexes were reconstituted with solubilized FPR from partially and fully desensitized neutrophils with increasing concentrations of Gi purified from bovine brain. The respective EC\(_{50}\) values for reconstitution were similar to that determined for FPR from unstimulated neutrophils (Bommakanti RK et al., J Bio[ Chem 267: 757~7581, 1992). We conclude, therefore, that the affinity of the interaction of FPR with G protein is not affected by desensitization, consistent with the model of lateral segregation of FPR and G protein as a mechanism of desensitization. KW - Toxikologie KW - chemotactic receptors KW - G proteins KW - N-formyl peptides KW - signal transduction KW - receptor-G protein coupling Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60483 ER - TY - JOUR A1 - Klotz, Karl-Norbert A1 - Jesaitis, A. J. T1 - Neutrophil chemoattractant receptors and the membrane skeleton N2 - Signal transduction via receptors for N-formylmethionyl peptide chemoattractants (FPR) on human neutrophils is a highly regulated process which involves participation of cytoskeletal elements. Evidence exists suggesting that the cytoskeleton and/or the membrane skeleton controls the distributJon of FPR in the plane of the plasma membrane, thus controlling the accessibility of FPR to different proteins in functionally distinct domains. In desensitized cells, FPR are restricted todomains which are depleted of G proteins but enriched in cytoskeletal proteins such as actin and fodrin. Thus, the G protein signal transduction partners of FPR become inaccessible to the agonist-occupied receptor, preventing cell activation. The mechanism of interaction of FPR with the membrane skeleton is poorly understood but evidence is accumulating that suggests a direct binding of FPR (and other receptors) to cytoskeletal proteins such as actin. KW - Toxikologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60471 ER - TY - JOUR A1 - Klotz, Karl-Norbert A1 - Krotec, K. L. A1 - Gripentrog, J. A1 - Jesaitis, A. J. T1 - Regulatory interaction of N-formyl peptide chemoattractant receptors with the membrane skeleton in human neutrophils N2 - The cytoskeleton and/or membrane skeleton has been implicated in the regulation of N-formyl peptide receptors. The coupling of these chemotactic receptors to the membrane skeleton was investigated in plasma membranes from unstimulated and desensitized human neutrophils using the photoreactive agonist N-formyl-met-leu-phelys-N\(^6\)-[\(^{125}\)I]2(p-azidosalicylamido)ethyl-1,3'-dithiopropionate (fMLFK-[\(^{125}\)I]ASD). When membranes of unstimulated cells were solubilized in Triton-X 100, a detergent that does not disrupt actin filaments, only 50% of the photoaffinity-labeled receptors were solubilized sedimenting in sucrose density gradients at a rate consistent with previous reports. The remainder were found in the pellet fraction along with the membrane skeletal actin. Solubilization of the membranes in the presence of p-chloromercuriphenylsulfonic acid, elevated concentrations of KCI, or deoxyribonuclease I released receptors in parallel with actin. When membranes from neutrophils, desensitized by incubation with fMLFK-e 251]ASD at 15°C, were solubilized, nearly all receptors were recovered in the pellet fraction. lncubation of cells with the Iigand at 4°C inhibited desensitization partially and prevented the conversion of a significant fraction of receptors to the form associated with the membrane skeletal pellet. ln these separations the photoaffinity-labeled receptors not sedimenting to the pellet cosedimented with actin. Approximately 25% of these receptors could be immunosedimented with antiactin antibodies suggesting that N-formyl peptide receptors may interact directly with actin. These results are consistent with a regulatory role for the interaction of chemotactic N-formyl peptide receptors with actin of the membrane skeleton. KW - Toxikologie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-60466 ER - TY - JOUR A1 - Pauli, Paul A1 - Lutzenberger, W. A1 - Rau, H. A1 - Birbaumer, N. A1 - Rickard, T. C. A1 - Yaroush, R. A. A1 - Bourne, L. E. J. T1 - Brain potentials during mental arithmetic: effects of extensive practice and problem difficulty N2 - Recent behavioral investigations indicate that the processes underlying mental arithmetic change systematically with practice from deliberate, conscious calculation to automatic, direct retrieval of answers from memory [Bourne, L.E.Jr. and Rickard, T.C., Mental calculation: The development of a cognitive skill, Paper presented at the Interamerican Congress of Psychology, San Jose, Costa Rica, 1991; Psychol. Rev., 95 (1988) 492-527]. Results reviewed by Moscovitch and Winocur [In: The handbook of aging and cognition, Erlbaum, Hillsdale, NJ, 1992, pp. 315-372] suggest that consciously controlled processes are more dependent on frontal lobe function than are automatic processes. It is appropriate, therefore to determine whether transitions in the locus of primary brain activity occur with practice on mental calculation. In this experiment, we examine the relationship between characteristics of event-related brain potentials (ERPs) and mental arithmetic. Single-digit mental multiplication problems varying in difficulty (problem size) were used, and subjects were trained on these problems for four sessions. Problem-size and practice effects were reliably found in behavioral measures (RT). The ERP was characterized by a pronounced late positivity after task presentation followed by a slow wave, and a negativity during response indication. These components responded differentially to the practice and problem-size manipulations. Practice mainly affected topography of the amplitude of positivity and offset latency of slow wave, and problem-size mainly offset latency of slow wave and pre-response negativity. Fronto-central positivity diminished from session to session, and the focus of positivity centered finally at centro-parietal regions. This finding suggests that frontal lobe processing is necessary as long as task performance is not automatized, while automatized arithmetic processing requires parietal brain activity only. The pre-response negativity observed in the first session and during more difficult tasks is assumed to reflect excitatory preparatory processes, which could be associated with activation of calculation strategies. KW - Psychologie KW - Mental arithmetic KW - Event-related potential KW - Practice KW - Automatization KW - Problem size Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61345 ER - TY - JOUR A1 - Nakayama, Ichiro A1 - Foresti, Fausto A1 - Tewari, Rita A1 - Schartl, Manfred A1 - Chourrout, Daniel T1 - Sex chromosome polymorphism and heterogametic males revealed by two cloned DNA probes in the ZW/ZZ fish Leporinus elongatus N2 - In order to study the divergence of teleost sex chromosomes, subtractive cloning was carried out between genomic DNA ofmales and females ofthe rainbow trout (XX/XY) and of Leporinus elongatus (ZW /ZZ). Inserts cloned in a plasmid vector were individually tested on Southern blots of DNA of males and females for sex specificity. No sex-specific insert was obtained from trout, but two out of ten inserts cloned from L. elongatus showed sex-specific patterns in this species: one corresponds to a sequence present on both Z and W chromosomes, while the other is W specific. Sequences of these two inserts show neither clear homology with other known sequences, nor an open reading frame. They cross-hybridize with the genomic DNA of Leporinusfriderici, but without sex-specific patterns. Twenty-four L. elongatus adults were sexed by gonadal observation, chromosomed examination and Southern hybridization with one or the other insert. Ten males and 11 females had chromosomes and hybridization patterns typical of their sex. One ZW female was recognized as a male with the W-specific probe. This was also the case for two unusual ZW males, one having a male hybridization pattern with the other probe. These three atypical individuals may result from single genetic exchanges between four regions of the Z and the W, giving rise to three atypical W chromosomes. Finding males with such atypical heterochromosomes in a female heterogametic species may indicate that a gradual transition occurs between the heterogametic systems. KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61583 ER - TY - JOUR A1 - Erbelding-Denk, Claudia A1 - Schroder, Johannes H. A1 - Schartl, Manfred A1 - Nanda, Indrajit A1 - Schmid, Michael A1 - Epplen, Jörg T. T1 - Male polymorphism in Limia perugiae (Pisces: Poeciliidae) N2 - The male-polymorphic poeciliid fish, Limia perugiae, a small teleostean endemic to the southeast of the Caribbean island Hispafiola, consists of three male size morphs with uniform females. Large males differentiate at a size va:rying between 25 and 38 mm; intermediate males, between 21 and 25 mm. Under competition, !arge males exhibit an elaborate courtship display, whereas small males show only a sneak-chase behavior. Intermediate males adapt their tactics to the respective competitors. However, all malemorphs can switch from courtship display to sneak-chase behavior. In large mating groups with four males of different size and five or six virgin females, large dominant a-males as weil as small subordinate \(\delta\)-males did not produce any offspring. Unexpectedly, all progeny were sired exclusively by the intemediate subordinate ß- and \(\gamma\)-males. Breeding experiments with the three male morphs can best be explained by a model of Y -linked genes for small and !arge size which are both suspended by the activity of an autosomal recessive repressor responsible for the development of intermediate males. The dominant allele of the recessive repressor, in either its homoorits heterozygous state, activates the Y-chromosomal genes for !arge or small size, respectively. Accordingly, intermediate males may produce male offspring of all size classes, depending on the presence of either the Y-linked gene or the autosomal repressor. KW - Physiologische Chemie KW - Poeciliid fish KW - male size polymorphism KW - reproductive success Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61573 ER - TY - JOUR A1 - Meyer, Axel A1 - Morrissey, Jean M. A1 - Schartl, Manfred T1 - Recurrent origin of a sexually selected trait in Xiphophorus fishes inferred from a molecular phylogeny N2 - DARWIN\(^1\) believed that sexual selection accounts for the evolution of exaggerated male ornaments, such as the sword-like caudal fin extensions of male fishes of the genus Xiphophorus, that appear detrimental to survival. Swordtails continue to feature prominently in empirical work and theories of sexual selection; the pre-existing bias hypothesis has been offered as an explanation for the evolution of swords in these fishes\(^{2,3}\). Based upon a largely morphological phylogeny, this hypothesis suggests that female preference to mate with sworded males arose in ancestrally swordless species, thus pre-dating the origin of the sword itself and directly driving its evolution. Here we present a molecular phylogeny (based on mitochondrial and nuclear DNA sequences) of Xiphophorus which differs from the traditional one: it indicates that the sword originated and was lost repeatedly. Our phylogeny suggests that the ancestor of the genus is more likely to have possessed a sword than not, thus questioning the applicability of the pre-existing bias hypothesis as an explanation for the cvolution of this sexually selected trait. KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61569 ER - TY - JOUR A1 - Malitschek, Barbara A1 - Wittbrodt, Joachim A1 - Fischer, Petra A1 - Lammers, Reiner A1 - Ullrich, Axel A1 - Schartl, Manfred T1 - Autocrine stimulation of the Xmrk receptor tyrosine kinase in Xiphophorus melanoma cells and identification of a source for the physiological ligand N2 - The melanoma·inducing gene of Xiphophorus fish encodes the Xmrk receptor tyrosine kinase. U sing a highly specific antiserum p~oduced against the recombinant receptor expressed with a baculovirus, it is shown that Xmrk is the most abundant phosphotyrosine protein in fish melanoma and thus highly activated in the tumors. Studies on a melanoma cellline revealed that these cells produce an activity that considerably stimulates receptor autophosphorylation. The stimulating activity induces receptor down-regulation and can be depleted from the melanoma cellsupernatant by the immobilized recombinant receptor protein. The fish melanoma cells can thus be considered autocrine tumor cells providing a source for future purification and characterization of the Xmrk ligand. KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61551 ER - TY - JOUR A1 - Götz, Rudolf A1 - Köster, Reinhard A1 - Winkler, Christoph A1 - Raulf, Friedrich A1 - Lottspeich, Friedrich A1 - Schartl, Manfred A1 - Thoenen, Hans T1 - Neurotrophin-6 is a new member of the nerve growth factor family N2 - DURING vertebrale development, many neurons depend for survival and differentiation on their target cells\(^{1-3}\). The best documented mediator of such a retrograde trophic action is the neurotrophin nerve growth factor (NGF)\(^1\). NGF and the other known members of tbe neurotrophin family, brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT -3) and neurotrophin-4/5 (NT -4/5) are conserved as distinct genes over large evolutionary distances\(^{4 -6}\). Here we report the cloning of neurotrophin-6 (NT -6), a new member of this family from the teleost fish Xiphophorus. NT -6 distinguishes itself from the other known neurotrophins in that it is not found as a soluble protein in the medium of producing cells. The addition of heparin (but not chondroitin) effects the release of NT -6 from cell surface and extracellular matrix molecules. Recombinant purified NT -6 has a spectrum of actions similar to NGF on chick sympathetic and sensory neurons, albeit with a lower potency. NT -6 is expressed in tbe embryonie valvulla cerebelli; expression persists in some adult tissues. The interaction of NT-6 with heparin-binding molecuJes may modulate its action in the nervous system . KW - Physiologische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-61544 ER - TY - JOUR A1 - Suter, H. U. A1 - Pleß, V. A1 - Ernzerhof, M. A1 - Engels, Bernd T1 - Difficulties in the Calculation of Electron Spin Resonance Parameters using Density Functional Methods N2 - Density functional theory is applied to the calculation ofthe isotropic byperfine coupJing constants in some small molecules. Various functionals are tested. The agreement of the calculated values to experimental data and values obtained from sophisticated ab initio methods depends on the functionals used and the system under consideration. With respect to spin density calculations the functional of Lee, Yang and Parr with Becke's excbange functional (BLYP) is found to give good results for tbe heavier center of the CH and the NH molecule, while the spin densities of other molecules such as OH, H\(_2\)CN, H\(_2\)CO\(^+\), NO and O\(_2\) deviate considerably from experimental and/or other theoretical results (30%-60%). In cases where the singly occupied orbital can contribute to the isotropic hyperfine coupling constants, accurate results are obtained. The reason fortbis is analyzed. KW - Organische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59113 ER - TY - JOUR A1 - Suter, H. U. A1 - Huang, M.-B. A1 - Engels, Bernd T1 - A Multireference Configuration Interaction Study of the Hyperfine Structure of the Molecules CCO, CNN and NCN in their triplet ground states N2 - The hyperfine structures of the isoelectronic molecules CCO. CNN, and NCN in their triplet ground states (X\(^3 \sum ^-\)) are investigated by means of ab initio methods. The infrared frequencies and geometries are detennined and compared with experiment. Configuration selected multireference configuration interaction calculations in combination with perturbation theory to correct the wave function (MRD-CI/B\(_K\)) employing extended atomic orbital (AO) basis sets yielded very accurate hyperfine properties. The theoretical values for CCO are in excellent agreement with the experimental values determined by Smith and Weltner [J. Chem. Phys. 62,4592 (1975)]. For CNN, the first assignment of Smith and Weltner for the two nitrogen atoms has to be changed. A qualitative discussion of the electronic structure discloses no simple relation between the structure of the singly occupied orbitals and the measured hyperfine coupling constants. Vibrational effects were found to be of little importance. KW - Organische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59108 ER - TY - JOUR A1 - Froudakis, G. A1 - Zdetsis, A. A1 - Mühlhäuser, M. A1 - Engels, Bernd A1 - Peyerimhoff, S. D. T1 - A comparative ab initio study of the Si\(_2\)C\(_4\), Si\(_3\)C\(_3\), Si\(_4\)C\(_2\) clusters N2 - Various structural possibilities for the Si\(_2\)C\(_4\) and Si\(_4\)C\(_2\) clusters are investigated by employing a basis set of triple-zeta plus polarization quality; electron correlation is generally accounted for by second-order M0ller-Plesset and, in certain instances, by higher-order perturbation (CASPT2) approaches. The building-up principle recently suggested from an analysis of Si\(_3\)C\(_3\) clusters is found to be fully operative for Si\(_2\)C\(_4\) and Si\(_4\)C\(_2\) clusters. A comparison of the structure and stability of various geometrical arrangements in the series C\(_6\) , Si\(_2\)C\(_4\) , Si\(_3\)C\(_3\) , Si\(_4\)C\(_2\), and Si\(_6\) shows that linear and planar structures become rapidly less stable if carbons are replaced by silicons and that the three-dimensional bipyramidal forms become less favorable as soon as silicons are exchanged by carbons in the parent Si\(_6\) structure. The effects can be rationalized in qualitative terms based on differences in silicon and carbon bonding. KW - Organische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59097 ER - TY - JOUR A1 - Staikova, M. A1 - Peric, M. A1 - Engels, Bernd A1 - Peyerimhoff, S. D. T1 - Ab initio Investigation of the Structure of the X\(^2\)A', A\(^2\)A'' (1\(^2\)Π) Spectral System of HCO: Investigation of the Magnetic Hyperfine Effects N2 - Results ofan ab initio study ofthe hyperfine structure of the X\(^2\)A', A\(^2\) A" ( 1\(^2 \Pi\)) system ofthe formyl radical are presented. Special attention is paid to the analysis of the interplay between the vibronic and magnetic hyperfine etfects. The results of computations are in very good agreement with the available experimental findings. The values for the hyperfine coupling constants in lower bending Ievels of both electronic species are predicted. KW - Organische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59089 ER - TY - JOUR A1 - Wortmann-Saleh, D. A1 - Engels, Bernd A1 - Peyerimhoff, S. D. T1 - Theoretical Study of the Reaction O(\(^3\)P) + C\(_2\)H\(_4\) and comparison with the \(^3\)CH\(_3\) + C\(_2\)H\(_4\) Reaction N2 - The minimum energy path for the reaction O(\(^3\)P\(_g\)) + C\(_2\)H\(_4\)(\(^1\)A\(_g\)) has been calculated by optimizing all relevant geometrical parameters along the approach of oxygen to ethene. A barrier of 4.7 kcal/mol in the \(^3\)A"( ... 9a'\(^2\)- 10a'3a") potential energy surface and an energy difference of 14.4 kcal/mol between the product and the fragments is found at the multireference-configuration interaction level. The corresponding values at the lower-level treatment CASSCF are 9 kcal/mol for the barrier and 9 kcal/mol for the depth of the potential; this shows the importance of inclusion of electron correlation. The barrier for CH\(_2\) rotation for the lowestenergy structure (asymmetric OC\(_2\)H\(_4\)) is around 5 kcal/mol. The energy gap to the first excited state \(^3\)A'( ... 9a'l0a'3a'12) is found tobe 3.6 kcal/mol in MRD-CI calculations at the ground-state minimum. Comparison with \(^3\)CH\(_2\) + C\(_2\)H\(_4\) shows that in this system the lowest-energy surface is \(^3\)A', i.e., the state which is the excited state in 0 + C\(_2\)H\(_4\). This difference in energy ordering of \(^3\)A' and \(^3\)A" states results from the fact that the p\(_x\), p\(_y\), p\(_z\) degeneracy of oxygen orbitals is lifted in \(^3\)CH\(_2\)leading to b\(_1\), b\(_2\). and a\(_1\) MOs whereby the lowest b\(_2\) (a") remains doubly occupied; as a consequence, the reaction pattem between the oxygen and \(^3\)CH\(_2\) approach is different, which is also quite apparent in the calculated charge transfer. KW - Organische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59076 ER - TY - JOUR A1 - Mühlhäuser, M. A1 - Froudakis, G. A1 - Zdetsis, A. A1 - Engels, Bernd A1 - Flytzanis, N. A1 - Peyerimhoff, S. D. T1 - Ab initio investigation of the stability of Si\(_3\)C<\(_3\) clusters and their structural and bonding features N2 - Various structural possibilities for Si\(_3\)C\(_3\) clusters are investigated by ab initio calculations employing basis sets of double- and triple-zeta quality augmented by d polarization functions. Correlation effects are included by a second-order Moeller Piesset perturbation treatment. For the two lowest-lying structures higher-order correlation corrections and multi-reference effects are also included. Bonding features are investigated by two different types of population analyses to obtain insight into the nature of chemical bonding. A total of 17 stationary points were investigated, 14 of which correspond to local minima and three being transition states. The energetically lowest-lying structures are: A "pyramidlike" structure with various multicenter bonds, followed by a es symmetric isomer closely related to the ground state Si6 structure. Planar structures, favoured in small carbon clusters, lie higher in energy and are transition states. The lowest-lying triplet system is found to be the linear nonsymmetric Si - C-C-C-Si -Si structure, which is calculated to lie about 38 kcalfmole above the singlet ground state. A building-up principle based on bonding criteria is suggested for the occurence of the various structural possibilities. KW - Organische Chemie Y1 - 1994 U6 - http://nbn-resolving.de/urn/resolver.pl?urn:nbn:de:bvb:20-opus-59060 ER -