Refine
Has Fulltext
- yes (147)
Is part of the Bibliography
- yes (147)
Year of publication
- 1989 (147) (remove)
Document Type
- Journal article (107)
- Book article / Book chapter (13)
- Conference Proceeding (8)
- Book (6)
- Review (6)
- Other (3)
- Report (2)
- Jahresbericht (1)
- Preprint (1)
Keywords
- Anorganische Chemie (9)
- Organische Chemie (9)
- Kind (8)
- Toxikologie (8)
- Psychologie (7)
- Infektionsbiologie (5)
- Neurobiologie (5)
- Biochemie (4)
- Biologie (4)
- Erziehung (3)
Institute
- Theodor-Boveri-Institut für Biowissenschaften (22)
- Institut für Psychologie (12)
- Institut für Psychologie (bis Sept. 2007) (12)
- Institut für Pharmakologie und Toxikologie (11)
- Institut für Molekulare Infektionsbiologie (10)
- Institut für Organische Chemie (10)
- Institut für Anorganische Chemie (9)
- Institut für Pädagogik (bis Sept. 2007) (8)
- Neuphilologisches Institut - Moderne Fremdsprachen (bis 2007) (6)
- Neurochirurgische Klinik und Poliklinik (6)
At early developmental stages (embryonic day 7, E7), chick paravertebral sympathetic ganglia contain a cell population that divides in culture while expressing various neuronal properties. In an attempt to identify factors that control neuronal proliferation, we found that ciliary neurotrophic factor (CNTF) specifically inhibits the proliferation of those cells expressing neuronal markers. In addition, CNTF affects the differentiation of sympathetic ganglion cells by inducing the expression of vasoactive intestinal peptide immunoreactivity (VIP-IR). After 1 day in culture, tyrosine hydroxylase immunoreactivity (TH-I R) was expressed by about 86% of the cells whereas VIP-IR was virtually absent. In the presence of CNTF, 50%-60% of the cells expressed VIP-IR after 4 days in culture; however, none of the cells expressed VIP-IR in the absence of CNTF. These results, and the demonstration of cells that express both VIP and TH-IR, indicate that VIP is induced in cells that initially express tyrosine hydroxylase. The findings suggest a potential role for CNTF as a factor affecting the proliferation and differentiation of developing sympathetic neurons.
Observations on captive reed frogs Hyperolius viridijlavus ommatostictus showed that seven out of 24 females changed into males. Sex change occurred without any hormone treatment and resulted in completely functional males. The adaptive value is discussed in terms of maximizing life-time reproductive success. Hyperolius r. ommatostictus is the first amphibian known to show functional sex reversal.
No abstract available.
Several exoproteins from Listeria monocytogenes serovar 4b (NCTC 10527) and Listeria ivanovii (ATCC) 19119, SLCC 2379), respectively, have been purified to homogeneity by thiol-disulfide exchange chromatography and gel filtration. Both strains produce a haemolytic/cytolytic protein of Mr 58 kDa, which has all the properties of a SH-activated cytolysin, the prototype of which is streptolysin 0 (SLO), and this protein has therefore heen termed Iisteriolysin 0 (LLO). In addition a protein of Mr 24 kDa from culture supernatants of L. ivanovii co-purified withLLO. The N-terminal aminoacid sequences of both proteins from L. ivanovii have been determined. By mutagenesis with transposons of Gram-positive origin (Tn916 and TnI545), which have been introduced via conjugation into L. ivanovii, several phenotypic mutants (altered haemolysis on sheep blood agar or lecithinase-negative) were obtained. Results on the properties of these muntants will he presented.
No abstract available
Radiation inactivation analysis of the binding of the A1 adenosine receptor antagonist, 8-cyclopentyl-1,3-dipropylxanthine to rat brain membranes yielded a radiation inactivation size of 58 kDa. In the presence of GTPyS this was reduced to 33 kDa, in good agreement with the size of the ligand-binding subunit detected after photoaffinity labelling. The data indicate that the structural association of A\(_1\) adenosine receptors with G-protein components is altered in situ in the presence of guanine nucleotides.
Although evidence obtained with the PC12 cell line has suggested a role for the ras oncogene proteins in the signal transduction of nerve growth factor-mediated fiber outgrowth, little is known about the signal transduction mechanisms involved in the neuronal response to neurotrophic factors in nontransformed cells. We report here that the oncogene protein T24-ras, when introduced into the cytoplasm of freshly dissociated chick embryonic neurons, promotes the in vitro survival and neurite outgrowth of nerve growth factor-responsive dorsal rootganglion neurons, brain-derived neurotrophic factor-responsive nodose ganglion neurons, and ciliary neuronotrophic factor-responsive ciliary ganglion neurons. The proto-oncogene product c-Ha-ras also promotes neuronal survival, albeit less strongly. No effect could be observed with truncated counterparts of T24-ras and c-Ha-ras lacking the 23 C-terminal amino acids including the membrane-an-choring, palmityl-accepting cysteine. These results sug-gest a generalized involvement of ras or ras-like proteins in the intracellular signal transduction pathway for neurotrophic factors.
Der größte Teil des zentralsaharischen Reliefs ist unter dem Einfluß nicht-arider Klimate gebildet worden. Andererseits gab es im Pleistozän äolisch geprägte aride Phasen, die extremer als heutige gewesen sind. Der Kenntnisstand zur Reliefgeschichte erlaubt es, daraus die Grundzüge der Klimageschichte eines großen Teils der südlich-zentralen Sahara abzuleiten.
No abstract available
Considering the very large industrial usage of benzene, studies in risk assessment aimed at the evaluation of carcinogenic risk at low Ievels of exposure are important. Animal data can offer indications about what could happen in humans and provide more diverse information than epidemiological data with respect to doseresponse consideration. We have considered experiments investigating metabolism, short·term genotoxicity tests, DNA adduct formation, and carcinogenicity long-term tests. According to the different experiments, a Saturation of benzene metabolism and benzene effects in terms of genotoxicity seems evident above 30 to 100 ppm. Below 30 to 60 ppm the initiating effect ofbenzene seems tobe linear fora large intervaJ ofdosages, at least judging from DNA adduct formation. Potentiallack of a promoting effect of benzene (below 10 ppm) could generate a sublinear response at nontox.ic levels of ex.posure. This possibility was suggested by epidemiological data in humans and is not confirmed or excluded by our observations with animals.
Role of alpha-Hemolysin for the in vitro Phagocytosis and intracellular killing of Escherichia coli
(1989)
The_role of a-hemolysin for the elimination of Eschericbia coli by phagocyres in vitro was investigated using sets of isogenic strains which included wild-type a -hemolyric srrains, derived strains with a reduced production of a-hemolysin and derived nonhemolytic strains. Phagocyrosis and intracellular killing of the bacteria by human blood granulocytes or monocytes were measured using growth inhibition rechniques. a-hemolytic strains were phagocytosed and killed ro a Jesser extent than isogenic strains with a reduced production of o:hemoJysin and isogenic nonhemolytic strains. The results obrained with granulocyres were similar to rhose obtained with monocyres although the elimination of bacteria by monocytes was less than that by granulocytes. These resulcs strongJy suggest that production of ahemolysin is a means by which E. coli counteracrs the activity of phagocytes by injuring these cells with the toxin.
Genetically cloned E. co/i strains expressing cloned virulence factors were studied with regard to their capability to induce inflammatory mediator release from various target cells. Among the strains were E. co/i strains with mannose-resistant haemagglutination (MRH +) and mannose-resistant adhesins, e.g. E. coli 536/21 pANN 80 I /4, E. coli 536/21 pANN 921 and E. coli 536/21 pANN 801-1. In comparison, E. coli 536/21, E. coli 536/21 pGB 30 int and E. coli Kl2, without and with mannosesensitive haemagglutination (MSH±), and adhesins were studied. The properties of the various strains for human PMN with regard to adherence and phagocytosis, chemiluminescence, 5-lipoxygenase activation of arachidonic acid, leukotriene formation, granular enzyme release and release of histamine from rat mast cells were analysed. It is evident that the various 'biochemical processes of cell activation are dissociated events. The highest chemiluminescence response is obtained with strains expressing MSH+, P-M RH+ or S-M RH+; the presence of S-adhesins suppressed the response. Highest leukotriene formation is obtained with E. coli 536/21 pANN 801-4, while E. coli with MSH was inactive. The concomitant presence of haemolysin secretion enhanced mediator release significantly. Our data suggest a potent role for mannose-resistant haemagglutination (MRH), adhesins and haemolysin as virulence factors in inducing the release of inflammatory mediators.
The term "speech chronemics" is introduced to characterize a research strategy which extracts from the physical qualities of the speech signal only the pattern of ons ("speaking") and offs ("pausing"). The research in this field can be structured into the methodological dimension "unit of time", "number of speakers", and "quality of the prosodic measures". It is shown that a researcher's actual decision for one method largely determines the outcome of his study. Then, with the Logoport a new portable measurement device is presented. It enables the researcher to study speaking behavior over long periods of time (up to 24 hours) in the normal environment of his subjects. Two experiments are reported. The first shows the validity of articulation pauses for variations in the physiological state of the organism. The second study proves a new betablocking agent to have sociotropic effects: in a long-term trial socially high-strung subjects showed an improved interaction behavior (compared to placebo and socially easy-going persons) in their everyday life. Finally, the need for a comprehensive theoretical foundation and for standardization of measurement situations and methods is emphasized.
Wenn Strafe und Schadenersatz gemeinsam im Urteil verwendet werden, bilden sie methodisch einen besonderen multi variaten Urteils komplex, weil auch ihre Summe psychologisch interpretierbar ist. Anhand der Effekte dieses Verbunds, den auch das Zivil- und Strafrecht kennt, wurde geprüft, ob der Einsatz eines Doppel-Urteils für die Erforschung sozialer Kognitionen erforderlich ist. Dazu beurteilten Pbn in zwei Untersuchungen Informationen über schädigende Handlungen mit einem univariaten Ersatz-Urteil (N = 124) bzw. mit dem Doppel-Urteil von Ersatz und Strafe (N = 143). Als Folge der Einführung des Doppel-Urteils ergab sich, daß die Häufigkeiten von Über kompensation für absichtliche Schädigungen erheblich reduziert wurden. Jedoch wurden zugleich die Häufigkeiten von vollem Ersatz bei diesen Bedingungen beträchtlich erhöht. Bei versehentlichen Schädigungen hatte die Einführung des Doppel-Urteils keinen Effekt. Weiterhin blieb dort der univariate Befund multipler Modalwerte erhalten. In den Mittelwerten hatte das Mitverschulden des Geschädigten nur im Schadensersatz-Urteil einen Effekt, nicht jedoch in den Strafurteilen. Außerdem blieb die für die Schadensersatz- Urteile charakteristische Non-Additivität von Verschulden und Mitschuld bestehen.
This study explored the differential effects of strategy training on German and American elementaryschool children and assessed the role of parents in the development of their children's strategic behavior and metacognition. 184 German and 161 American children were pretested on memory and metamemory tasks. Children were then assigned to either an organizational strategy training condition or a control condition. All children were tested on the maintenance and far-transfer of the strategy and task-related metamemory 1 week following training. Parents completed questionnaires about strategy instruction in the home. Strategy maintenance and metacognition were reassessed 6 months following training. German children were more strategic than American children. Instructed children performed better than control children. German parents reported more instruction of strategies in the home. These data suggest that formal education is responsible for aspects of cognitive development that have sometimes been viewed as a function of age.
In the humid tropics of SE Asia there are some 14 myrmecophytic species of the pioneer tree genus Macaranga (Euphorbiaceae). In Peninsular Malaysia a close association exists between the trees and the small, non-stinging myrmicine Crema togas ter borneensis. These ants feed mainly on food bodies provided by the plants and have their colonies inside the hollow intemodes. In a ten months field study we were able to demonstrate for four Macaranga species (M. triloba, M. hypoleuca, M. hosei, M. hulletti) that host plants also benefit considerably from ant-occupation. Ants do not contribute to the nutrient demands of their host plant, they do, however, protect it against herbivores and plant competition. Cleaning behaviour of the ants results in the removal of potential herbivores already in their earliest developmental stages. Strong aggressiveness and a mass recruiting system enable the ants to defend the host plant against many herbivorous insects. This results in a significant decrease in leaf damage due to herbivores on ant-occupied compared to ant-free myrmecophytes as well as compared to non-myrmecophytic Macaranga species. Most important is the ants' defense of the host plant against plant competitors, especially vines, which are abundant in the well-lit pioneer habitats where Macaranga grows. Ants bite off any foreign plant part coming into contact with their host plant. Both ant-free myrmecophytes and non-myrmecophytic Macaranga species had a significantly higher incidence of vine growth than specimens with active ant colonies. This may be a factor of considerable importance allowing Macaranga plants to grow at sites of strongest competition.
Multi-reference configuration interaction calculations employing various orbital transformations are undertaken to obtain the isotropic hyperfine coupling constant a\(_{iso\) in nitrogen and a\(_{iso\) (H) in the CH molecule. The natural orbital (NO) basis is found to be more effective than the simple RHF-MO basis; the most obvious is a basis of spin natural orbitals (SNO). It is found that a\(_{iso\) is approached from opposite sides in the NO and 2s shell SNO basis if the CI expansion is increased. Both results are within a few percent of the full CI Iimit for the nitrogen atorn (in the given AO basis) and the experimental value for Hin the CH radical. Various features ofthe SNO are discussed.
1 Adenosine and its metabolically stable analogue N.etbyl-carboxamidoadenosine (NECA) enhance histamine release from rat peritoneal mast cells when tbese are stimulated by calciummobilizing agents. NECA and adenosine shift the concentration-response curve of tbe calcium ionophore A23187 to lower concentrations. 2 The potencies of NECA or adenosinein enhancing A23187-induced histamine release are dependent on the Ievel of stimulated release in tbe absence of adenosine analogues. At high Ievels of release their potencies are up to 20 times higher than at low Ievels. Consequently, averaged concentration-response curves of adenosine and NECA for enhancing bistamine release are shallow. 3 The adenosine transport blocker S-(p-nitrobenzyl)-6-thioinosine (NBTI) has no effect by itself at low Ievels of stimulated histamine release, but abolishes the enhancing effect of adenosine. At high Ievels of release, however, NBTI alone enhances the release of histamine. 4 lt is concluded that adenosine and calcium reciprocally enhance the sensitivity of the secretory processes to the effects of the other agent. The Ievels of intracellular adenosine obtained by trapping adenosine inside stimulated mast cells are sufficient to enhance histamine release substantially, suggesting that this effect may play a physiological and pathophysiological role.
Sila-Hexocyclium-methylsulfat (7b), ein Silicium-Analogon des therapeutisch eingesetzten Antimuscarinileums Hexocyclium-methylsulfat (7a), wurde durch eine sechsstufige Synthese - ausgehend von (CH\(_3\)0)\(_3\)SiCH\(_2\)Cl - dargestellt (Gesamtausbeute 16%). Außerdem wurden die hiervon abzuleitende freie Base 9b (fünfstufige Synthese, ausgehend von (CH\(_3\)0)\(_3\)SiCH\(_2\)O; Gesamtausbeute 29%) und das strukturverwandte (Aminomethyl)silanol 13 (dreistufige Synthese, ausgehend von cyclo-C\(_6\)H\(_{11}\)(C\(_6\)H\(_5\))Si(OCH\(_3\))CH\(_2\)Cl, Gesamtausbeute 46$) synthetisiert. 7b ist ein hochwirksames und selektives Antimuscarinikum, das in der experimentellen Pharmakologie aufgrund seines bemerkenswerten Selektivitätsprofils zur Klassifizierung von Subtypen muscarinischer Rezeptoren eingesetzt wird.
The synthesis of the potent and highly selective silicon-containing antimuscarinic agent o-methoxysila- hexocyclium methyl sulfate and its corresponding tertiary amine (isolated as the dihydrochloride) is described. The quarternary compound is an omethoxy derivative of sila-hexocyclium methyl sulfate, which represents one of the tools currently used in experimental pharmacology for the subclassification of muscarinic receptors. The omethoxy derivative, the pharmacological profile of which differs substantially from tbat of the nonmethoxy compound, is also recommended as a tool for the investigation of muscarinic receptor heterogeneity.
A MODEL of good information processing is sketched, describing how metacognitive knowledge influences strategy selection and use. Three factors pose particular problems for learning disabled students as they attempt to acquire metacognitive knowledge and to use study strategies productively: neurological impairments; deficiencies in general world knowledge; and negative beliefs, attitudes, and styles that limit self-efficacy. Creating an educational atmosphere that explicitly builds conceptual (domain-specific) knowledge and teaches positive beliefs about learning potential is essential in promoting metacognitively-oriented instruction.
We have previously reported that analgesic doses of morphine accelerate mortality of rats exposed to hemorrhage (Feuerstein and Siren: Circ Shock 19:293-300, 1986). To study the potential mechanisms involved in this phenomenon, rats were chronically implanted with catheters in the femoral vessels and morphine (1.5 or 5 mg/kg) was administered 30 min or 24 hr after bleeding (8.5 mll300 g over 5 min) while arterial blood pressure and heart rate were continuously monitored. Furthermore, the effect of morphine (5 mg/kg) on cardiac output (CO) response to hemorrhage was studied in rats chronically equipped with a mini thermistor for CO monitoring by a thermodilution technique. In addition, plasma catecholamines (HPLC), plasma renin activity (PRA, RIA), vasopressin (RIA), pH, and blood gases were also determined. Morphine administration 30 min after hemorrhage produced a pressor response and tachycardia which were in marked contrast to its depressor effect in intact rats. Morphine elevated PRA and epinephrine but not vasopressin, while blood pH and gases showed no consistent change as compared to salinetreated hemorrhaged rats. Morphine given after the bleeding resulted in enhanced cardiac depression in response to a second bleed of 2 m1l300 g. Our data suggest that activation of pressor mechanisms by morphine during hypovolemic hypotension might enhance vasoconstriction in essential organs, depress cardiac function, and further reduce effective tissue perfusion.
The isotropic (a\(_{iso}\)) and dipolar (A\(_{dip}\)) hyperfine coupling constants of 19F2 were obtained from MRD-CI wave functions using a variety of basis sets. In series I, increasing numbers of d functions were added to a 5s4p contracted Huzinaga!Dunning basis. In series II, the 5s3p basis set was uncontracted in several steps until 9s5p was reached, to which were added from one to three d-polarization functions. Cl parameters (selectioo threshoids and the number of reference coofiguratioos) were also varied. A study of the R dependence of aiso and Adip was perfonned. The best values obtained at R\(_e\) are 260 G for a\(_{iso}\) and 308 G for A\(_{dip}\)• compared with experimental values of about 280 G for a;10 and 320 G for A\(_{dip}\)·
The hyperfine coupling constants for the \(^3\)Σ\(-\) ground state of the NH molecule are determined by configuration interaction calculations whereby the infl.uence of polarization functions as weil as of the configuration space on the spin polarization mechanism is analysed. The dipolar part Au(N) and Au(H) can be obtained very reliably without much computational effort (A .. (N) == -45·3 MHz and A"(H) = -62·3 MHz). The value for the isotropic contribution a1.., in the best AO basis and MRD-CI treatment is - 64·5 MHz for H and 16·6 MHz for nitrogen compared to the corresponding experimental quantities of -66 MHz and 19 MHz respectively. Their determination depends on a subtle balance of the lu, 2u and 3u shell correlation description, whereby the dominant contribution to a1..,(H) results from the 2u shell. It is shown that the often good agreement of a110 values with experiment in a small basis singledouble configuration interaction treatment results from a cancellation of two errors.
In a short-term longitudinal study, we investigated how domain-specific knowledge in soccer influences the amount of text recall and comprehension in elementary school and junior high school children of high and low overall aptitudes. Both level of soccer knowledge and overall aptitude were varied in a factorial design. Third, fifth, and seventh grade children were given several measures of text recall and comprehension and were retested on these measures about 1 year later. Performance was more a function of soccer knowledge than of aptitude level.
Large-scale multireference configuration interaction (MRD-CI) calculations in a quite flexible AO basis are employed to study the energy hypersurface for the reaction intermediate FC\(_2\)H\(_4\) • The reaction F + C\(_2\)H\(_4\) -> FC\(_2\)H\(_4\) as weil as the 1,2 migration of the fluorine atom in FC\(_2\)H\(_4\) is investigated. In addition the rotation around the CC bond in the optimum conformation is studied. The absolute minimum in the potential energy is found for the asymmetric structure but the symmetric structure is also found to be stable with respect to the dissociation, so that a shuttling of the fluorine atom is in principle possible but highly unlikely because ( l) the activation energy is high ( II 5-130 kJ fmol) and the saddle point lies only 4(}-50 kJ jmol below the dissociation Iimit of F + C\(_2\)H\(_4\) and (2) the competitive motion, i.e., rotation around the CC axis, is nearly free (I 1-17 kJ/mol).
Dications 1 derived from 2,2-bipyridine are found to exist as fully reversible two step redox systems with persistent radical ions (SEM) of high thermodynamic stability, if the bridge X forces the two pyridine rings into co planar positions. The well known derivative 1a (Diquat R) is now complemented by the boronium ions 1c and 1e -1g., as shown by voltammetry and the uv spectra of the corresponding radicals.
No abstract available
Vorwort (Das Kind (1989) 5)
(1989)
No abstract available
Vorwort (Das Kind (1989) 6)
(1989)
No abstract available
No abstract available
No abstract available
No abstract available.
Die Ergebnisse einer publizierten Arbeit zur Validierung von acht Konfigurationen generalisierter Kontrollüberzeugungen werden durch drei weitere Auswertungsschritte ergänzt. Die Anwendung der Interaktionsstrukturanalyse führt zu einer Hervorhebung von zwei Konfigurationen als Typen und zur Aufstellung einer 5-Gruppen-Hypothese über die Bildung einer Restgruppe aus den Neutral-Konfigurationen. Die Betrachtung der Unterschiede in den FPI-Mittelwerten der ursprünglichen acht Gruppen bestätigt die 5-Gruppen-Hypothese. Mit einer multidimensionalen geometrischen Darstellung der Profildistanzen wird in einem dritten Schritt versucht, neben der "Restgruppe" und den beiden "Typen"-Gruppen auch die Eigenständigkeit der beiden verbleibenden "Anti-Typen"-Gruppen zu validieren.
Mit einem besonderen multivariaten Urteilsverbund von Ersatz und Strafe als abhängige Variable wurden die Wirkungen von Entschuldigung und Verschulden untersucht. 62 erwachsene Pbn beurteilten in zehn Geschichten über eine Briefmarkenruinierung die angemessene Strafe für den Schädiger und verbunden damit dessen angemessene Ersatzleistung an den Geschädigten und anschließend in vierzehn Geschichten über eine Körperverletzung beim Fußballspielen zusätzlich zu Strafe und Ersatz auch das angemessene Schmerzensgeld. In bei den Szenarien ergab sich, daß die Entschuldigung auf das Ersatz-Urteil zwar weniger stark als auf die Strafe wirkte, daß sie aber einen deutlichen Effekt auf das Ersatz-Urteil besaß. Weiterhin wurden die Verschuldensstufen auf beiden Skalen mit anderen relativen Distanzen beurteilt. Die Schmerzensgeld-Urteile im Fußball- Szenario ähnelten weitgehend den Strafe-Urteilen. Auch die Verteilungsformen der Urteile belegten die unterschiedlichen Verwendungsweisen der Teile des Urteilsverbunds. Die untersuchten Urteile scheinen daher zugleich restitutive und punitive Strukturen aufzuweisen, zu deren quantitativer Erfassung Forschungsansätze nötig sind, die den hier eingeführten Duplex-Verbund von Strafe und Ersatz beinhalten.