@article{WuBeckerWaagetal.1991,
author = {Wu, Y.S. and Becker, Charles R. and Waag, A. and Kraus, M. M. and Bicknell-Tassius, R. N. and Landwehr, G.},
title = {Correlation of the Cd-to-Te ratio on CdTe surfaces with the surface structure},
isbn = {0163-1829},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-37789},
year = {1991},
abstract = {We report here that reconstruction on (100), (1lIlA, and (1l1lB CdTe surfaces is either C(2X2), (2X2), and (l X I) or (2X I), (l X I), and (l X I) when they are Cd or Te stabilized, respectively. There is a mixed region between Cd and Te stabilization in which the reflected high-energy electron-diffraction (RHEED) patterns contain characteristics of both Cd- and Te-stabilized surfaces. We have also found that the Cd-to-Te ratio of the x-ray photoelectron intensities of their 3d\(_{3/ 2}\) core levels is about 20\% larger for a Cd-stabilized (1lIlA, (1lIlB, or (100) CdTe surface than for a Te-stabilized one. According to a simple model calculation, which was normalized by means of the photoelectron intensity ratio of a Cd-stabilized (lll)A and aTe-stabilized (1l1lB CdTe surface, the experimental data for CdTe surfaces can be explained by a linear dependence of the photoelectron-intensity ratio on the fraction of Cd in the uppermost monatomic layer. This surface composition can be correlated with the surface structure, i.e., the corresponding RHEED patterns. This correlation can in turn be employed to determine Te and Cd evaporation rates. The Te reevaporation rate is increasingly slower for the Te-stabilized (Ill) A, (l1l)B, and (100) surfaces, while the opposite is true for Cd from Cd-stabilized (Ill) A and (Ill)B surfaces. In addition, Te is much more easily evaporated from all the investigated surfaces than is Cd, if the substrate is kept at normal molecular-beam-epitaxy growth temperatures ranging from 2oo·C to 300 ·C.},
subject = {Festk{\"o}rperphysik},
language = {en}
}
@article{WuBeckerWaagetal.1991,
author = {Wu, Y. S. and Becker, Charles R. and Waag, A. and Bicknell-Tassius, R. N. and Landwehr, G.},
title = {The effects of laser illumination and high energy electrons on molecular-beam epitaxial growth of CdTe},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-30795},
year = {1991},
abstract = {We report the results of a detailed investigation on the Te-stabilized (2 x 1) and the Cdstabilized c( 2 X 2) surfaces of ( 100) CdTe substrates. The investigation demonstrates for the first time that both laser illumination and, to a greater extent, high-energy electron irradiation increase the Te desorption and reduce the Cd desorption from ( 100) CdTe surfaces. Thus it is possible by choosing the proper growth temperature and photon or electron fluxes to change the surface reconstruction from the normally Te-stabilized to a Cd-stabilized phase.},
language = {en}
}
@article{WintermeyerRdestLudwigetal.1991,
author = {Wintermeyer, E. and Rdest, U. and Ludwig, B. and Debes, A. and Hacker, J{\"o}rg},
title = {Characterization of legiolysin (lly); responsible for hemolytic activity, colour production and fluorescence of Legionella pneumophila},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59706},
year = {1991},
abstract = {No abstract available},
subject = {Infektionsbiologie},
language = {en}
}
@inproceedings{WinotoMorbachUlrichsMuellerRuchholtz1991,
author = {Winoto-Morbach, S. and Ulrichs, Karin and M{\"u}ller-Ruchholtz, W.},
title = {New Developments in Biodegradable Microspheres For Magnetic Separation Techniques},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-45712},
year = {1991},
abstract = {No abstract available},
subject = {Immunbiologie},
language = {en}
}
@article{WinklerVielkindSchartl1991,
author = {Winkler, Christoph and Vielkind, J{\"u}rgen R. and Schartl, Manfred},
title = {Transient expression of foreign DNA during embryonic and larval development of the medaka fish (Oryzias latipes)},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61743},
year = {1991},
abstract = {Species of small fish are becoming useful tools for studies on vertebrate development. Wehave investigated the developing embryo of the Japanese medaka for its application as a transient expression system for the in vivo analysis of gene regulation and function. The temporaland spatial expression patterns ofbacterial chloramphenicol acetyltransferase and galactosidase reporter genes injected in supercoiled plasmid form into the cytoplasm of one cell of the two-cell stage embryo was promoter-specific. The transient expression was found to be mosaic within the tissue and organs reflecting the unequal distribution of extrachromosomal foreign DNA and the intensive cell mixing movements that occur in fish embryogenesis. The expression data are consistent with data on DNA fate. Foreign DNA persisted during embryogenesis and was still detectable in some 3- and 9-month-old adult fish; it was found in high molecular weight form as weil as in circular plasmid conformations. The DNA was replicated during early and late embryogenesis. Our data indicate that the developing medaka embryo is a powerful in vivo assay system for studies of gene regulation and function.},
subject = {Physiologische Chemie},
language = {en}
}
@article{WilhelmZaccagnini1991,
author = {Wilhelm, Gernot and Zaccagnini, Carlo},
title = {Excavations at Tell Karrana 3 (1985 and 1986)},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85963},
year = {1991},
abstract = {no Abstract available},
subject = {Tell Karrana},
language = {en}
}
@article{Wilhelm1991,
author = {Wilhelm, Gernot},
title = {A Hurrian Letter from Tell Brak},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-85972},
year = {1991},
abstract = {No abstract available.},
subject = {Tell Brak},
language = {en}
}
@article{WaelbroeckCamusTastenoyetal.1991,
author = {Waelbroeck, M. and Camus, J. and Tastenoy, M. and Mutschler, E. and Strohmann, C. and Tacke, Reinhold and Lambrecht, G. and Christophe, J.},
title = {Binding affinities of hexahydro-difenidol and hexahydro-sila-difenidol analogues at four muscarinic receptor subtypes: constitutional and stereochemical aspects},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64128},
year = {1991},
abstract = {Hexahydro-sila-difenidoJ and eight analogues behaved as simple cumpetitive inhibitors of eHJN·methyl·scopoJamine binding to homogenates frorn human neuroblastoma NB-OK 1 cells (M\(_1\) sites), rat heart (M\(_2\) sites), rat pancreas (M\(_3\) sites), and rat striatum 'B' sites (M\(_4\) sites). Pyrrolidino- and hexamethyleneimino analogues showed the same sekctivity profile as the parent compound. Hexahydro-sila-difenidol methiodide and the methiodide of p-fluoro-hexahydro·sila-difenidol had a f{\"u}gher affinity but a lower selectivity than the tertiary amines. Compounds containing a p·methoxy, p-chJoro or p-fluoro substituent in the phenyl ring of hexahydro-sila-difenidol showed a qualitative)y similar selectivity profile as the parent compound (i.e., M\(_1\)= M\(_3\) = M\(_4\) >M\(_2\) ), but up to 16-fold lower affinities. o-Methoxy-hexahydro-sila-difenidol has a lower affinity than hexahydro-sila-difeni.:!o! at the four binding sites. lts selectivity profile (M\(_4\) > M\(_1\), M\(_3\) > M\(_2\) ) was different from hexahydro-sila-difenidol. Replacement of the centrat silicon atom of hexahydro-sila-difenidol, p-fluoro-hexahydro-sila-difenidol and thdr quatemary (N-methylated) analogues by a carbon atom did not change their binding affinities significantly. The iour muscarinic receptors showed a higher affinity for the (R)- than for the (S)-enantiomers of hexahydro-difenidol, p-fluorohexahydro-difenidol and their methiodides. The stereoselectivity varied depending on the receptor subtype and drug considered.},
subject = {Anorganische Chemie},
language = {en}
}
@article{WaelbroeckCamusTastenoyetal.1991,
author = {Waelbroeck, M. and Camus, J. and Tastenoy, M. and Mutschler, E. and Strohmann, C. and Tacke, Reinhold and Lambrecht, G. and Christophe, J.},
title = {Stereoselectivity of (R)- and (S)-hexahydro-difenidol binding to neuroblastoma M\(_1\), cardiac M\(_2\), pancreatic M\(_3\), and striatum M\(_4\) muscarinic receptors},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64135},
year = {1991},
abstract = {(R)-Hexahydro-difenidol has a higher affinity for M\(_1\) receptors in NB-OK 1 cells, pancreas M\(_3\) and striatum M\(_4\) receptors (pKi 7.9 to 8.3) than for cardiac M2 receptors (pKi 7 .0). (8)-Hexahydro-difenidol, by contrast, is nonselective (pKi 5.8 to 6.1). Our goal in the present study was to evaluate the importance ofthe hydrophobic phenyl, and cyclohexyl rings of hexahydro-difenidol for the stereoselectivity and reeeptor selectivity of hexahydro-difenidol binding to the four muscarinic receptors. Our results indieated that replacement of the phenyl ring of hexahydro-difenidol by a cyclohexyl group <~ dicyclidol) and ofthe cyclohexyl ring by a phenyl moiety <~ difenidol) indueed a !arge (4- to 80-fold) decrease in binding affinity for all musearlnie receptors. Difenidol had a signifieant preference for M\(_1\) , M\(_3\) , and M\(_4\) over M\(_2\) receptors; dicyclidol, by eontrast, had a greater affinity for M\(_1\) and M\(_4\) than for M\(_2\) and M\(_3\) receptors. The binding free energy deerease due to replacement ofthe phenyl and the cyelohexyl groups of(R)-hexahydro-difenidol by, respectively, a eyclohexyl and a phenyl moiety was almostadditive in the ease of M\(_4\) (striatum) binding sites. In the ease ofthe cardiac M\(_2\), pancreatic M\(_3\) , or NB-OK 1 M\(_1\) receptors the respective binding free energies were not eompletely additive. These results suggest that the four (R)-hexahydro-difenidol ''binding moieties" (phenyl, cyclohexyl, hydroxy, and protonated amino group) cannot simultaneously form optimal interaetions with the M\(_1\), M\(_2\), and M\(_3\) muscarinic receptors. When eaeh of the hydrophobic groups is modified, the position of the whole molecule, relative to the four subsites, was changed to allow an optimal overall interaction with the musearlnie receptor.},
subject = {Anorganische Chemie},
language = {en}
}
@article{VortkampThiasGessleretal.1991,
author = {Vortkamp, A. and Thias, U. and Gessler, Manfred and Rosenkranz, W. and Kroisel, P. M. and Tommerup, N. and Kruger, G. and Gotz, J. and Pelz, L. and Grzeschik, Karl-Heinz},
title = {A somatic cell hybrid panel and DNA probes for physical mapping of human chromosome 7p},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59217},
year = {1991},
abstract = {No abstract available},
subject = {Biochemie},
language = {en}
}
@article{VonhofSirenFeuerstein1991,
author = {Vonhof, S. and Sir{\´e}n, Anna-Leena and Feuerstein, G.},
title = {Central ventilatory effects of thyrotropin-releasing hormone in the conscious rat},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63075},
year = {1991},
abstract = {Thyrotropin-releasing hormonewas shown to exert potent ventilatory effects after centrat administration. These data, however, were derived from studies using anesthetized animal preparations. Since TRH elicits strong arousal reactions, the observed ventilatory effects of TRH under anesthesia may have been due to nonspecific reduction in the anesthetic state of the animals. In order to clarify the extent to which the reversal of anesthesia may change ventilatory parameters after TRH application, we investigated the effect of TRH on Ventilation rate, relative tidal volume, relative respiratory minute volume, CO\(_2\) production CO\(_2\) consumption, and locomotor activity in the conscious, unrestrained rat. Intracerebroventricular application of TRH induced a dose-dependent, sustained increase in ventilation rate, relative tidal volume, and relative respiratory minute volume of maximally 128\%, 890\%, and 235\%, respectively. In addition, CO\(_2\) production and O\(_2\) consumption were elevated by 4.6 and 11.7 fold, whiJe no significant changes in locomotor activity were observed. The results suggest that TRH stimulates ventilation by a mechanism independent of its analeptic properties.},
subject = {Neurobiologie},
language = {en}
}
@article{VonhofSiren1991,
author = {Vonhof, S. and Sir{\´e}n, Anna-Leena},
title = {Reversal of µ-opioid-mediated respiratory depression by α2-adrenoceptor antagonism},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47454},
year = {1991},
abstract = {The present study was performed in order to evaluate the effects of the selective 02- adrenoceptor antagonist 6-chloro-2,3,4,5-tetrahydro-3-methyl-1H-3-benzazepine (SK\&F 86466) on dermorphin-induced analgesia, respiratory depression and inhibition of locomotor activity in the conscious rat. Intracerebroventricular (icv) administration of dermorphin (3 nmol/rat) decreased respiration rate and relative ventilatory minute volume maximally by 38 \% and 50 \% of baseline respectively. SK\&F 86466 dose-dependently reversed the dermorphin-induced depression of ventilatory parameters, while SK\&F 86466 exerted no effect on dermorphin-induced analgesia or depression of locomotor activity due to catalepsia. It appears, therefore, that a 2-adrenoceptors selectively interact with Jl2-opioid-receptor mediated effects, such as respiratory depression, but are not involved in the modulation of Jl,-opioid-related effects, such as supraspinal analgesia and depression of locomotor activity.},
subject = {Biowissenschaften},
language = {en}
}
@article{VanDieKramerHackeretal.1991,
author = {Van Die, I. and Kramer, C. and Hacker, J{\"o}rg and Bergmans, H. and Jongen, W. and Hoekstra, W.},
title = {Nucleotide sequence of the genes coding for minor fimbrial subunits of the F1C fimbriae of Escherichia coli},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-40353},
year = {1991},
abstract = {F 1 C fimbriae allow uropathogenic Escherichia coli to adhere to specific epithelial surfaces. This adhesive property is probably due to the presence of minor fimbrial components in F1C fimbriae. The foe gene cluster encoding F1C fimbriae has been cloned, as described previously. Here we present the nucleotide sequence (2081 bp) coding for the F 1 C minor fimbria I subunits. The structural genes code for polypeptides of 175 (FocF), 166 (FocG), and 300 (FocH) amino acids. The deduced amino acids of the F 1 C minor subunits were compared with the reported sequences of the minor subunits of other types of fimbriae. The data show that the Foc minor subunits are highly homologous to the corresponding Sfa proteins, whereas homology to the minor subunits of type 1 and P fimbriae is much lower.},
language = {en}
}
@article{vanCalkerSteberKlotzetal.1991,
author = {van Calker, D. and Steber, R. and Klotz, Karl-Norbert and Greil, W.},
title = {Carbamazepine distinguishes between adenosine receptors that mediate different second messenger responses},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60392},
year = {1991},
abstract = {The mechanism of the therapeutic and prophylactic effects of carbamazepine (CBZ) in affective psychoses is unknown but may in part be related to the potent competitive interaction of CBZ with adenosine-binding sites in the brain. The antioonvulsant and sedative properties of CBZ are reminiscent of the effects evoked by adenosine-agonists and contrast sharply with the opposite aclions of adenosine-antagonists like caffeine. However. indirect evidence suggests an antagonist- rather than an agonist-like activity of CBZ at adenosi11e-receptors. We have used various model systems, in which adenosine receptor subtypes mediate different second messenger-responses, to investigate this apparent paradox. CBZ was found to antagonize the A\(_1\) receptor-mediated inhibition of cydic AMP accumulation in cultured astroblasts and in GH3-cells. Furthermore, CBZ also inhibits the adenosine-induced increase in the level of cyclic AMP in cultured astroblasts, which is mediated by low-affinity A\(_{2b}\)-receptors. ln contrast, CBZ does not block the inhibition elicited by adenosine-agonists of the agonist-induced increased formation of inositolphosphates in human neutrophils, which is mediated by high-affinity A\(_{2a}\)-receptors. The specific antagonism by CBZ of A\(_1\)- but not of high-affinity A\(_{2a}\)-receptors was further supported by binding experiments using rat brain membranes. These results suggest tbat the paradox of CBZ's antagonistic effects at adenosine-receptors might be at least partially reconciled by a selective antagonistic action of CBZ at A\(_1\)recertors but not at high-affinity A\(_{2a}\)-receptors.},
subject = {Toxikologie},
language = {en}
}
@article{UlrichsMuellerRuchholtz1991,
author = {Ulrichs, Karin and M{\"u}ller-Ruchholtz, Wolfgang},
title = {Modulation of pancreatic islet allo immunogenicity and immunobiological in vitro and in vivo consequences},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-78261},
year = {1991},
abstract = {No abstract available.},
subject = {Immunobiologie},
language = {en}
}
@inproceedings{UlrichsEulerMuellerRuchholtz1991,
author = {Ulrichs, Karin and Euler, HH and M{\"u}ller-Ruchholtz, W.},
title = {A Clinically Successful Protocol to Suppress Autoantibody Production in SLE Patients Is Analyzed For Its Efficacy To Inhibit Natural Xenophile Antibodies (NXA)},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-45693},
year = {1991},
abstract = {No abstract available},
language = {en}
}
@article{TonyLehrnbecherMerzetal.1991,
author = {Tony, H. P. and Lehrnbecher, T. and Merz, H. and Sebald, Werner and Wilhelm, M.},
title = {Regulation of IL-4 responsiveness in lymphoma B cells},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62520},
year = {1991},
abstract = {The responsiveness to IL-4 with and without costimulation with anti-IgM antibodies or phorbolester was studied in 35 cases of low grade non-Hodgkin Iymphoma by analyzing enhancement of CD23 and HLA dass li expression. The predominant phenotype responds directly to IL-4. Separate differentiation states can be distinguished according to coordinate or differential upregulation of CD23 and HLA dass II molecules by IL-4 alone, and differences in responsiveness to anti-IgM antibodies. A particular subgroup of B-lymphoma cells defines a separate stage of B-eeil differentiation. They fail to express high affinity binding sites for IL-4 and accordingly do not respond to IL-4- mediated signals. Cross-linking membrane lgM receptors or direct activation of protein kinase C via phorbolester induces IL-4 receptor expression and subsequent IL-4 reactivity.},
subject = {Biochemie},
language = {en}
}
@article{ThiryScheerGoessens1991,
author = {Thiry, Marc and Scheer, Ulrich and Goessens, Guy},
title = {Localization of nucleolar chromatin by immunocytochemistry and in situ hybridization at the electron microscopic level},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-39289},
year = {1991},
abstract = {Nucleoli are the morphological expression of the activity of a defined set of chromosomal segments bearing rRNA genes. The topological distribution and composition of the intranucleolar chromatin as well as the definition of nucleolar structures in which enzymes of the rDNA transcription machinery reside have been investigated in mammalian cells by various immunogold labelling approaches at the ultrastructural level. The precise intranucleolar location of rRNA genes has been further specified by electron microscopic in situ hybridization with a non-autoradiographic procedure. Our results indicate that the fibrillar centers are the sole nucleolar structures where rDNA, core histones, RNA polymerase I and DNA to po isomerase I are located together. Taking into account the potential value and limitations of immunoelectron microscopic techniques, we propose that transcription of the rRNA genes takes place within the confines of the fibrillar centers, probably close to the boundary regions to the surrounding dense fibrillar component.},
language = {en}
}
@article{TasStopperKoscheletal.1991,
author = {Tas, P. and Stopper, Helga and Koschel, K. and Schiffmann, D.},
title = {Influence of the carcinogenic oestrogen diethylstilboestrol on the intracellular calcium level in C6 rat glioma cells},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63459},
year = {1991},
abstract = {The ~fthetic oes~rog~n diethylsti~boestrol (DES) causes a dose-dependent elevation of the cytoplasuuc Ca concentratton m C6 rat ghoma cells. This Ca2+ rise is caused neither by Ca2+ influx nor ~-r release from the ~a2 + stores of the endoplasmic reticulum. Therefore it seems likely that DES mob!hzes Ca2+ from a nutochondrial source. The DES-induced Ca2+ signal is remarkably similar to the one mduced by the. tumou~ promotor ~hapsigargin. As this compound causes leakage of calcium from the endoplasmt~ rettculum tt ~ms posstble that DES induces a similar leakage from mitochondrial Ca2+ stores. It remaans to be estabhshed whether the DES-mediated rise in intracellular calcium is causally related to the tumour-promoting properties of this compound},
subject = {Toxikologie},
language = {en}
}
@article{TackeMahnerStrohmannetal.1991,
author = {Tacke, Reinhold and Mahner, K. and Strohmann, C. and Forth, B. and Mutschler, E. and Friebe, T. and Lambrecht, G.},
title = {Cyclohexyl(4-fluorophenyl)(3-piperidinopropyl)silanol (p-fluoro-hexahydro-sila-difenidol, p-F-HHSiD) and derivatives: synthesis and antimuscarinic properties},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64162},
year = {1991},
abstract = {Four different syntheses of the potent and selective muscanruc antagonist cyclohexyl( 4- fluorophenyl)(3-piperidinopropyl)silanol ( p-fluoro-hexahydro-sila-difenidol, p-F-HHSiD (2b); isolated as hydrochloride 2b· HCl) are described (starting materials: (CH\(_3\)O)\(_2\)SiCH\(_2\)CH\(_2\)CH\(_2\)Cl and Si(OCH\(_3\))\(_4\) ). In addition, the synthesis of the corresponding carbon analogue p-fluoro-hexahydro-difenidol ( p-F-HHD (2a); isolated as 2a· HCI) and the syntheses of three p-F-HHSiD derivatives (3-5), with a modified cyclic amino group, are reported (3: piperidinojpyrrolidino exchange, isolated as 3· HCI; 4: piperidinoj hexamethylenimino exchange, isolated as 4 · HCl; 5: quaternization of 2b with methyl iodide). The chiral compounds 2a, 2b, 3, 4 and 5 were prepared as racemates. In functional pharmacological studies, 3-5 behaved as simple competitive antagonists at musearlnie Ml receptors in rabbit vas deferens, M2 receptors in guinea-pig atria, and M3 receptors in guinea-pig ileal smooth rnuscle. The pyrrolidino (3) and hexamethylenimino (4) analogues of the parent drug p-F-HHSiD (2b) displayed the highest affinity for Ml and M3 receptors (pA\(_2\) values: 7.0-7.4) but exhibited lower affinity for cardiac M2 receptors (pA\(_2\) : 5.9 and 6.0). Their affinity profile (Ml- M3 > M2) is different from that of p-F-HHSiD (2b) (M3 > Ml > M2), but qualitatively very similar tothat of p-F-HHD (2a). The methiodide 5 exhibited the highest affinity for Ml receptors (pA\(_2\) : 8.5) but lower affinity for M2 and M3 receptors by factors of 5.6 and 3.6, respectively.},
subject = {Anorganische Chemie},
language = {en}
}
@article{TackeBrakmannWuttkeetal.1991,
author = {Tacke, Reinhold and Brakmann, S. and Wuttke, F. and Fooladi, J. and Syldatk, C. and Schomburg, D.},
title = {Stereoselective microbial reduction of racemic acetyl(t-butyl)methylphenylsilane by Trigonopsis variabilis (DSM 70714) and Corynebacterium dioxydans (ATCC 21766)},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64109},
year = {1991},
abstract = {(SiR,CR)- and (SiS,CR)-t-butyl(l-hydroxyethyl)methylphenylsilane [(SiR,CR)-2 and (SiS,CR)-3] have been prepared by (R)-selective microbial rcduction of racemic acetyl(t-butyl)methylphenylsilane (rac-1) using resting free cells of the yeast Trigonopsis variabilis (DSM 70714) or the bacterium Corynebacterium dioxydans (ATCC 21766). The biotransfonnations were carried out on a 10 g scale. Afterseparation by column chromatography on silica gel, the optically active diastereomers (SiR,CR)-2 and (SiS,CR)-3 produccd by T. variabilis were obtained in good yields [74\% ((SiR,CR)-2). 78\% ((SiS,CR)-3)]. The products obtained from the reduction with C. dioxydans were isolated in significantly lower yields [20\% ((SiR,CR)-2), 20\% ((SiS,CR)-3)]; reaction conditions not optimized). Both bioconversions gave products with high enantiomeric purities (T. variabilis: 91\% ee ((SiR,CR)-2), 96\% ee ((SiS,CR)-3); C. dioxydons: ~ 991 ee ((SiR,CR)-l), ~ 99\% ee ((SiS,CR)-3)). To throw light on the stereochemical aspects of these biotransfonnations, an X-ray diffraction study was carried out on the 3,5-dinitrobenzoate of rac-(SiR,CS/SiS,CR)-3. In addition, 1H NMR spectroscopic stereochemical correlation studies were performed with the (S)-MTPA esters derived from (SiR,CR)-l, (SiS,CR)-3, rac-(SiR,CRjSiS,CS)-2 and rac-(SiR,CSjSiS,CR)-3 [rac-(SiR,CR/ SiS,CS)-2 and rac-(SiR,CS/SiS,CR)-3 were obtained by reduction of rac-1 with LiAIH\(_4\) in diethylether, followed by chromatographic separation of the diastereomers on silica gel]. These stereochemical studies allowed assignment of the absolute configurations and enantiomeric purities of the biotransformation products.},
subject = {Anorganische Chemie},
language = {en}
}
@article{StoeckliLililienNaeherNoeetal.1991,
author = {St{\"o}ckli, K. A. and Lililien, L. E. and N{\"a}her- No{\´e}, M. and Breitfeld, G. and Hughes, Richard A. and Raff, M. C. and Thoenen, Hans and Sendtner, Michael},
title = {Regional distribution, developmental changes, and cellular localization of CNTF-mRNA and protein in the rat brain},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31172},
year = {1991},
abstract = {Ciliary neurotrophic factor (CNTF) is a potent survival molecule for a variety of embryonic neurons in culture. The developmental expression of CNTF occurs clearly after the time period of the physiological cell death of CNTF-responsive neurons. This, together with the sites of expression, excludes CNTF as a target-derived neuronal survival factor, at least in rodents. However, CNTF also participates in the induction of type 2 astrocyte differentiation in vitro. Here we demonstrate that the time course of the expression of CNTF-mRNA and protein in the rat optic nerve (as evaluated by quantitative Northern blot analysis and biological activity, respectively) is compatible with such a glial differentiation function of CNTF in vivo. We also show that the type 2 astrocyte-inducing- activity previously demonstrated in optic nerve extract can be precipitated by an antiserum against CNTF. Immunohistochemical analysis of astrocytes in vitro and in vivo demonstrates that the expression of CNTF is confined to a subpopulation of type 1 astrocytes. The olfactory bulb of adult rats has comparably high levels of CNTF to the optic nerve, and here again, CNTF-immunoreactivity is localized in a subpopulation of astrocytes. However, the postnatal expression of CNTF in the olfactory bulb occurs later than in the optic nerve. In other brain regions both CNTF-mRNA and protein levels are much lower.},
language = {en}
}
@article{StrohmannBauereckerCammengaetal.1991,
author = {Strohmann, C. and Bauerecker, S. and Cammenga, H. K. and Jones, P. G. and Mutschler, E. and Lambrecht, G. and Tacke, Reinhold},
title = {Enantiomers of the muscarinic antagonist 1-cyclohexyl-1-(4-fluorophenyl)-4-piperidino-1-butanol (p-fluoro-hexahydro-difenidol): synthesis, absolute configuration, and enantiomeric purity},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64144},
year = {1991},
abstract = {The enantiomers of the antimuscarinic agent 1-cyclohexyl-1- (4-fluorophenyl)-4-piperidino-1-butanol [(R)- and (S)-p-fluorohexahydro- difenidol] ((R)- and (S)-2a] and their methiodides (R)- 3 and (S)-3 were prepared with high enantiomeric purity. (R)- 2a and (S)-2a (isolated as hydrochlorides) were obtained by catalytic hydrogenation (Pd/C contact) of the corresponding enantiomers of 1-cyclohexyl-1-( 4-fl uorophen yl)-4-piperidino- 2-butyn-1-ol [(R)- and (S)-4]. Reaction of (R)-2a and (S)-2a with rnethyl iodide led to (R)-3 and (S)-3, respectively. The unsaturated precursors (R)- and (S}-4 (enantiorneric purity ~ 99.80 and ~99.94\% e.e.; calorimetric analysis) were prepared by res-sepaolution of rac-4 [available from 4-FC\(_6\)H\(_4\)C(O)C\(_6\)H\(_{11}\) by reaction with LiC ~ CCH\(_2\)NC\(_5\)H\(_{10}\)] using (R)- and (S)-mandelic acid as resolving agents. The absolute configurations of the (R) and (S) enantiomers of 2a, 3, and 4 were determined by an X-ray crystal-structure analysis of (S)-5, the methiodide of (S)-4. (R)- 2a and (R)-3 exhibit a higher affinity for muscarinic M1, M2, M3, and M4 receptors (by up to two orders of magnitude) than their corresponding antipodes (S)-2a and (S)-3, the degree of stereoselectivity depending on the receptor subtype involved. (R)-2a represents a useful tool for rnuscarinic receptor research (affinity profile: M1 ~ M3 ~ M4 > M2).},
subject = {Anorganische Chemie},
language = {en}
}
@article{StopperMetzler1991,
author = {Stopper, Helga and Metzler, M.},
title = {Carcinogenic oestrogens induce respiration deficiency mutation in yeast},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63466},
year = {1991},
abstract = {In addition to hormonal activity, genetic darnage has been proposed as an important factor in oestrogen-mediated carcinogenesis. However, as short-term tests for oestrogens usually fail to show DNA mutations, lesions other than dassie nuclear DNA mutation have to be considered. Oestrogeninduced mitochondrial darnage was studied in the yeast Saccharomyces cerevisiae. Stilbene-type, but not steroidal, oestrogens were found to induce respiration-dcficient petite mutation. The effect was inversely correlated with cytotoxicity and required aromatic hydroxyl groups at the stilbene molecule. It only occurred under growth conditions and apparently was not due to the A TPase inhibitory qualities of stilbene oestrogens. Other studies have shown that petite mutation clones, which can be induced by a variety of substances, contain altered mitochondrial DNA. The mechanism of petite mutation induction might be important in tumorigenesis by also acting on nuclear DNA or facilitating carcinogenesis by disturbance of mitochondrial function.},
subject = {Toxikologie},
language = {en}
}
@incollection{SpielmannArendKlotzetal.1991,
author = {Spielmann, W. S. and Arend, L. J. and Klotz, Karl-Norbert and Schwabe, U.},
title = {Adenosine control of the renal Collecting tubule: receptors and signaling},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86129},
publisher = {Universit{\"a}t W{\"u}rzburg},
year = {1991},
abstract = {No abstract available.},
subject = {Adenosin},
language = {en}
}
@article{SolbachMollRoellinghoff1991,
author = {Solbach, Werner and Moll, Heidrun and R{\"o}llinghoff, Martin},
title = {Lymphocytes play the music but the macrophage calls the tune},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-45889},
year = {1991},
abstract = {No abstract available},
subject = {Immunologie},
language = {en}
}
@article{SirenVonhofFeuerstein1991,
author = {Sir{\´e}n, Anna-Leena and Vonhof, S. and Feuerstein, G.},
title = {Hemodynamic defense response to thyrotropin-releasing hormone injected into medial preoptic nucleus in rats},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63099},
year = {1991},
abstract = {No abstract available},
subject = {Neurobiologie},
language = {en}
}
@article{SirenFeuerstein1991,
author = {Sir{\´e}n, Anna-Leena and Feuerstein, G.},
title = {Hypothalamic opioid µ-receptors regulate discrete hemodynamic functions in the conscious rat},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-63069},
year = {1991},
abstract = {The effect of the selective \(\mu\)-opioid agonist o-Ala\(^2\)-Me-Phe\(^4\)-Gly-ol'-enkephalin (DAGO), injected into the medial preoptic nucleus of hypothalamus, on cardiac output and regional blood flow was studied in the conscious rat and the effect of DAGO on renal sympathetic nerve activity and renal blood flow was studied in anesthetized rats. In conscious rats, injections of DAGO (1 or 10 nmol) into the preoptic nucleus increased the blood pressure in a dose-related manner. The maximum rises of mean arterial pressure and pulse pressure after the larger dose were +23 ± 5 mmHg (mean ±SEM, P < 0.01) and + 17 ± 3 mmHg(P < 0.01), respectively. A small dose (0.1 nmol) increased heart rate ( +47 ± 13 bpm, P < 0.05); thc 1 nmol dosc produced bradycardia (- 39 ± 11 bpm, P < 0.05), while the 10 nmol dose initially decreased heart rate ( -68 ± 15 bpm (P < 0.01) and then gradually increased heart rate to a maximum of + 74 ± 13 bpm, (P < 0.0 1). A long-lasting increase in cardiac output was also elicited by DAGO, with maximum changes after 1 and 10 nmol of + 14 ± 6\% and +22 ± 7\% (P < 0.01), respectively. B1ood flow in the hindquarters increascd after DAGO but the mesenteric and renal blood ftow decreased in a dose-related manner. Significant responscs in hindquarter and mesenteric blood fl.ow after DAGO were independent of systemic hemodynamic responses at the dose ofO.l nmol. The vascular resistance in the hindquarters significantly decreased after a small dose of DAGO while the larger doses dose-dependently increased mesenteric and renal vascular resistance. A crucial role of the sympathetic nervous system in the hemodynamic effects of DAGO was demonstrated: (1) by the profound activation of renal sympathetic nerve activity after injections of DAGO (I nmol/100 nl) into the preoptic nucleus, (2) by blockade of the pressor, tachycardic and regional hemodynamic effects of DAGO (I nmol) by the ganglion blocker ch1orisondamine (5 mg/kg i.v.). The results suggest that the pressor effect of DAGO in preoptic nucleus is due primarily to an increase in cardiac output. The differential changes in blood ftow in organs further suggest that the opioid \(\mu\)-receptors in the preoptic nucleus might be involved in the integration of peripheral blood ftow in the hypothalamus during affective behavior.},
subject = {Neurobiologie},
language = {en}
}
@incollection{ShephardMeierLutz1991,
author = {Shephard, S. E. and Meier, I. and Lutz, Werner K.},
title = {Alkylating potency of nitrosated amino acids and peptides},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86320},
publisher = {Universit{\"a}t W{\"u}rzburg},
year = {1991},
abstract = {Tbe alkylating potency of unstable N-nitrosamino acids and N-nitrosopeptides was investigated in vitro using 4-(para-nitrobenzyl)pyridine (NBP) as nucleophile. Of the amino acids, Met and those with an aromatic side chain were the most potent. The relative overall alkylating potency was 23:10:5:4:2:1: for Trp, Met, His, 1)rr, Phe and Gly, respectively. The homo-dipeptides were much more potent than the amino acids, with relative potencies of 400:110:100:8:3:1, for Trp-Trp, l)T-'I)T, Met-Met, Asp-Asp, Phe-Phe and Gly, respectively. In the one-phase reaction system (in which NBP is already present durlog the nitrosation reaction at acidic pH), all amino acids tested showed a second-order reaction for nitrite. In the two-phase system (in which NBP is added only after bringing the nitrosation reaction mixture to neutrality), all amino acids tested except one again showed a second-order reaction for nitrite (Phe, His, Asp and the dipeptide artiticial sweetener aspartame); only Met under these conditions bad a reaction order of one for nitrite. This could mean that nitrosation of the side chain of Metproduces a second N-nitroso product which is relatively stable in acid but reacts with NBP under neutral conditions. In the human stomach, this side-chain nitrosation might become more important than the reactions at the primary amino group, firstly because of the greater stability of the product(s) in acid and secondly because of the tirst-order reaction rate for nitrite. A decrease in nitrite concentration from the millimolar concentrations ofthe in-vitro assay to the micromolar concentrations in the stomach reduces the reaction rate by a factor of 1000 for the side-chain nitrosation, whereas a million-fold reduction will be observed for nitrosation of the amino group.},
subject = {Aminos{\"a}uren},
language = {en}
}
@misc{SendtnerArakawaStoecklietal.1991,
author = {Sendtner, Michael and Arakawa, Yoshihiro and St{\"o}ckli, Kurt A. and Kreutzberg, Georg W. and Thoenen, Hans},
title = {Effect of ciliary neurotrophic factor (CNTF) on motoneuron survival},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-33048},
year = {1991},
abstract = {We have demonstrated that the extensive degeneration of motoneurons in the rat facial nucleus after transection of the facial nerve in newborn rats can be prevented by local ciliary neurotrophic factor (CNTF) administration. CNTF differs distinctly from known neurotrophic molecules such as NGF, BDNF and NT-3 in both its molecular characteristics (CNTF is a cytosolic rather than a secretory molecule) and its broad spectrum of biological activities. CNTF is expressed selectively by Schwann cells and astrocytes of the peripheral and central nervous system, respectively, but not by target tissues of the great variety of CNTF -responsive neurons. CNTF mRNA is not detectable by Northern blot or PCR analysis during embryonic development and immediately after birth. However, during the second post-natal week, a more than 30-fold increase in CNTF mRNA and pro tein occurs in the sciatic nerve. Since the period of low CNTF levels in peripheral nerves coincides with that of high vulnerability of motoneurons (i.e. axonallesion results in degeneration of motoneuron cell bodies), insufficient availability of CNTF may be the reason for the rate of lesioninduced cell death of early post-natal motoneurons. Highly enriched embryonic chick motoneurons in culture are supported at survival rates higher than 60\% by CNTF, even in single cell cultures, indicating that CNTF acts directly on motoneurons. In contrast to CNTF, the members of the neurotrophin gene family (NGF, BDNF and NT-3) do not support the survival of motoneurons in culture. However, aFGF and bFGF show distinct survival activities which are additive to those of CNTF, resulting in the survival of virtually all motoneurons cultured in the presence of CNTF and bFGF.},
language = {en}
}
@article{SchuesslerTalarico1991,
author = {Sch{\"u}ssler, Ulrich and Talarico, F.},
title = {Granulite facies rocks from the Ross orogenic belt, Northern-Victoria-Land, Antarctica},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-81889},
year = {1991},
abstract = {no abstract available},
subject = {Geographie},
language = {en}
}
@article{SchueleinKreftGonskietal.1991,
author = {Sch{\"u}lein, Ralf and Kreft, J{\"u}rgen and Gonski, Sigrid and Goebel, Werner},
title = {Preprosubtilisin Carlsberg processing and secretion is blocked after deletion of amino acids 97-101 in the mature part of the enzyme},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-60577},
year = {1991},
abstract = {During an investigation into the substrate specificity and processing of subtilisin Carlsberg from Bacillus licheniformis, two major independent findings were made: (i) as has been shown previously, a stretch of five amino acids (residues 97-101 of the mature enzyme) that loops out into the binding cleft is involved in substrate binding by subtilisin Carlsberg. In order to see whether this loop element also determines substrate specificity, the coding region for these five amino acids was deleted from the cloned gene for subtilisin Carlsberg by site-directed mutagenesis. Unexpectedly the resulting mutant preproenzyme (P42c, Mr=42 kDa) was not processed to the mature form (Mr = 30 kDa) and was not released into the medium by a proteasedeficient B. subtilis host strain; rather, it accumulated in the cell membrane. This result demonstrates that the integrity of this loop element, which is very distant from the processing cleavage sites in the preproenzyme, is required for secretion of subtilisin Carlsberg. (ii) In culture supernatants from B. subtilis harbouring the cloned wild-type subtilisin Carlsberg gene the transient appearance (at 0-3 h after onset of stationary phase) of a processing intermediate (P38c, Mr = 38 kDa) oftbis protease could be demonstrated. P38c very probably represents a genuine proform of subtilisin Carlsberg.},
subject = {Biologie},
language = {en}
}
@article{SchrotenWolskePlogmannetal.1991,
author = {Schroten, Horst and Wolske, Anja and Plogmann, Ricarda and Hanisch, Franz-Georg and Hacker, J{\"o}rg and Uhlenbr{\"u}ck, Gerhard and Wahn, Volker},
title = {Binding of cloned S-fimbriated E. coli to human buccal epithelial cells-different inhibition of binding by neonatal saliva and adult saliva.},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86291},
year = {1991},
abstract = {Investigations were carried out on the adhesion of cloned S-fimbriated E. coli, labelled with fluoresceinisothiocyanate (FITC) to human buccal epithelial cells. Fluorescence microscopic analysis revealed binding of bacteria to 75-95\% of epithelial cells. Inhibition experiments with fetuin, a 1-acid glycoprotein and N-acetyl neuraminic acid confirmed the specificity of bacterial binding to sialoglycoproteins. Further studies using saliva as an inhibitor resulted in a 4-5 times stronger binding inhibition by newborn saliva in comparison to adult saliva coinciding with a 4-5 times higher content of total N-acetyl neuraminic acid in samples of newborn saliva. In Western blot analysis sialoglycoprotein bands with a molecular weight >200 kD reacting with wheat germ agglutinin (WGA), were only identified in samples of newborn saliva. These bands are classified as mucins on account of molecular weight and staining. These data suggest that saliva mucins could represent a major defense mechanism against bacterial infections at a stage of ontogeny where the secretory IgAsystem is not yet developed.},
subject = {Escherichia coli},
language = {en}
}
@article{SchneiderSchauliesKrethHofmannetal.1991,
author = {Schneider-Schaulies, Sibylle and Kreth, H. W. and Hofmann, G. and Billeter, M. A. and ter Meulen, V.},
title = {Expression of measles virus RNA in peripheral blood mononuclear cells of patients with measles, SSPE, and autoimmune diseases},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62297},
year = {1991},
abstract = {No abstract available},
subject = {Virologie},
language = {en}
}
@article{SchneiderSchauliesKirchhoffArchelosetal.1991,
author = {Schneider-Schaulies, J{\"u}rgen and Kirchhoff, F. and Archelos, J. and Schachner, M.},
title = {Downregulation of Myelin Associated Glycoprotein (MAG) on Schwann cells by interferon-gamma and tumor necrosis factor-alpha affects neurite outgrowth},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-54850},
year = {1991},
abstract = {To investigate the influence of inflammatory cytokines on the potential of peripheral nerves to regenerate, we analyzed the effect of interferon-y (lFN-y) and tumor necrosis factor-a (TNF-a) on the ability of immortalized Schwann cells to mediate outgrowth of neurites from primary DRG neurons. We found that IFN-y and TNF-a synergistically inhibited the neurite outgrowth-promoting properties of the Schwann cells by spedfically dowllregulating myelin-associated glycoprotein (MAG) at the levels of mRNA and cell surface protein by approximately 60\%. Antibodies to MAG inhibited the outgrowth of neurites on Schwann cells to the same extent as treatment with the two cytokines. Since MAG appears to be involved in both neurite outgrowth and myelination, our findings may provide evidence for a mechanism, by wh ich inflammatory cytokines interfere with Schwann cell-neuron interactions.},
subject = {Immunologie},
language = {en}
}
@article{SchneiderSodian1991,
author = {Schneider, Wolfgang and Sodian, Beate},
title = {A longitudinal study of young children's memory behavior and Performance in a sort-recall task},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62169},
year = {1991},
abstract = {No abstract available},
subject = {Psychologie},
language = {en}
}
@article{Schneider1991,
author = {Schneider, Wolfgang},
title = {Domain-specific knowledge and memory Performance},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-50494},
year = {1991},
abstract = {No abstract available},
subject = {Psychologie},
language = {en}
}
@article{SchluppParzefallSchartl1991,
author = {Schlupp, I. and Parzefall, J. and Schartl, Manfred},
title = {Male mate choice in mixed bisexual/-unisexual breeding complexes of Poecilia (Teleostei: Poeciliidae)},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-80309},
year = {1991},
abstract = {The livebearing all-female fish Poecilia formosa reproduces by gynogenesis, a modified form of parthenogenesis. P. formosa forms at least two breeding complexes: in its northern range it exists sympatrically with Poecilia latipinna and in its southern range with Poecilia mexicana. Differences between these complexes and their possible origin are discussed. Embryogenesis is triggered by sperm of males of these closely related sympatric species. Because inheritance is stricdy maternal, from the male point of view energy and time invested are totally lost. In this study we wanted to elucidate whether males are able to distinguish between conspecific and parasitic females. It could be shown that males are able to distinguish females optically, but that this ability was obscured as soon as chemical and/or tactile contact was possible. Furthermore, we found that females in an attractive phase of their sexual cycle are always preferred, regardless of species. This is possibly the mechanism by which parasitic females obtain the matings they need to reproduce.},
subject = {Poecilia (Teleostei: Poeciliidae)},
language = {en}
}
@article{SchartlSchluppSchartletal.1991,
author = {Schartl, Manfred and Schlupp, Ingo and Schartl, Angelika and Meyer, Manfred K. and Nanda, Indrajit and Schmid, Michael and Epplen, J{\"o}rg T. and Parzefall, Jakob},
title = {On the stability of dispensable constituents of the eukaryotic genome: Stability of coding sequences versus truly hypervariable sequences in a clonal vertebrate, the amazon molly, Poecilia formosa},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61731},
year = {1991},
abstract = {In dooal unisexual vertebrales, the genes specifying the males become dispensable. To study tbe rate of such geoes the gynogeoetic all-female fisb Poecilillfonnolll was treated with androgens. Phenotypic males were obtained that exbibited the complete set of male cbaracteristics of dosely related gooocboristic species, induding body proportions, pigmentation, the extremely complex insemination apparatus of poecil{\"u}d fish, sexual bebavior, and spermatogeoesls. Tbe apparent stabllity of such genic structures, induding those involved in androgen regulation, is contrasted by high instability of noncoding sequeaces. Frequent mutations, thelr donal transmission, and at least two truly hypervariable Iod leading to individual difl'ereaces between these othenrise donal organisms were detected by DNA fingerprinting. These observations substantiate the concept that also in "ameiotic" vertebrates certain compartments of the genome are more prooe to mutatiooal alterations than others.},
subject = {Physiologische Chemie},
language = {en}
}
@article{SchartlErbeldingDenkNandaetal.1991,
author = {Schartl, Manfred and Erbelding-Denk, Claudia and Nanda, Indrajit and Schmid, Michael and Schr{\"o}der, Johannes Horst and Epplen, J{\"o}rg T.},
title = {Mating success of subordinate males in a poeciliid fish species, Limia perugiae},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-86349},
year = {1991},
abstract = {No abstract available.},
subject = {Lebendgeb{\"a}rende Zahnkarpfen},
language = {en}
}
@article{RettingerBurschkaScheebenetal.1991,
author = {Rettinger, Klaus and Burschka, Christian and Scheeben, Peter and Fuchs, Heike and Mosandl, Armin},
title = {Chiral 2-alkylbranched acids, esters and alcohols. Preparation and stereospecific flavour evaluation},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-31898},
year = {1991},
abstract = {Racemic 2-alkylbranched acids are transformed to diastereomeric derivatives with (S)-2-hydroxy-3-phenylpropionic acid-N-methylamide or (S)-(-)-l-phenylethylamine and separated by liquid chromatography to pure diastereoisomers, which are subsequently hydrolyzed to yield optically pure acids. Enantiomeric alcohols are generated by LiAlH4-reduction of the corresponding acids, esters are synthesized by different methods. The odour impression of the enantiomeric compounds is investigated.},
subject = {S{\"a}ure},
language = {en}
}
@article{RethwilmErlweinBaunachetal.1991,
author = {Rethwilm, Axel and Erlwein, Otto and Baunach, Gerald and Mauerer, Bernd and ter Meulen, Volker},
title = {The transcriptional transactivator of human foamy virus maps to the bel 1 genomic region},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47342},
year = {1991},
abstract = {The human foamy virus (HFV) genome possesses three open reading frames (bel I, 2, and 3) located between env and the 3' long terminal repeat. By analogy to other human retroviruses this region was selected as the most Iikely candidate to encode the viral transactivator. ResuIts presented here confirmed this and showed further that a deletion introduced only into the bell open reading frame of a plasmid derived from an infectious molecular clone of HFV abolished transactivation. In contrast, deletions in bel 2 and bel 3 had only minor effects on the ability to transactivate. The role of the bel I genomic region as a transactivator was further investigated by eukaryotic expression of a genome fragment of HFV spanning the bel I open reading frame. A construct expressing bell under control of a heterologous promoter was found to transactivate the HFV long terminal repeat in a dose-dependent fashion. Furthermore, it is shown that the U3 region of the HFV long terminal repeat is sufficient to respond to the HFV transactivator.},
subject = {Virologie},
language = {en}
}
@article{PreiserSchmartzVanderLindenetal.1991,
author = {Preiser, J. C. and Schmartz, D. and Van der Linden, P. and Content, J. and Vanden Bussche, P. and Buurman, W. and Sebald, Werner and Dupont, E. and Pinsky, M. R. and Vincent, J. L.},
title = {Interleukin-6 administration has no acute hemodynamic or hematologic effect in the dog},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-62511},
year = {1991},
abstract = {To investigate the possible hemodynamic efl'ects of interleukin-6 (IL-6), a single dose of 15 mcg/kg of recombinant IL-6 isolated from Escherichia coli was injected intravenously in six pentobarbital-anesthetized dogs. After 30 min, saline infusion was performed to maintain the - pulmonary artery balloon-occluded pressure at baseline Ievel. The animals were observed for up to 5 hours. No other hemodynamic alteration was observed than a gradual decline in cardiac output attributed to anesthesia. Hematologic variables, blood glucose, and total serum proteins were also constant. IL-6 levels were markedly elevated in the blood, bot no tumor necrosis factor activity was detected. Thus a primary role for IL-6 in the early cardiovascular alterations associated with septic shock seems unlikely.},
subject = {Biochemie},
language = {en}
}
@article{PfefferSchoelGulleetal.1991,
author = {Pfeffer, K. and Schoel, H. and Gulle, H. and Moll, Heidrun and Kromer, S. and Kaufmann, S. H. E. and Wagner, H.},
title = {Analysis of primary T cell responses to intact and fractionated microbial pathogens},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-46916},
year = {1991},
abstract = {Freshly isolated human T lymphocytes were tested for their response to mycobacteria, mycobacteriallysates, 2 dimensional (2D) PAGE separated mycobacteriallysates, leishmania and defined leishmanial antigen preparations. While,o T cells proliferated vigourously in the presence of mycobacteria and mycobacteria derived lysates, a significant stimulation from 2 D gel separated lysates was not detected. In addition '10 T cells failed to respond towards leishmania or leishmanial components. In the ab T cell compartment some donors, presumably according to their state of immunity against mycobacteria, responded to mycobacteria, mycobacterial lysates and 2 D gel separated mycobacterial lysates. Neither freshly isolated '10 T cells nor ab T cells from naive donors did mount a significant immune response against leishmania.},
language = {en}
}
@article{PericEngelsPeyerimhoff1991,
author = {Peric, M. and Engels, Bernd and Peyerimhoff, S.D.},
title = {Ab initio investigation of the vibronic structure of the C\(_2\)H spectrum Calculation of the hyperfine coupling constants for the three lowest lying electronic states},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58901},
year = {1991},
abstract = {The hyperfine coupling constants (isotropic hfcc and four Cartesian components of the ani~ tropic tensor) are calculated for all three atoms of C\(_2\)H in its three lowest-lying electronic states at various molecu)ar geometries by means of the ab initio configuration interaction ( MRO.CI) method. The off-diagonal electronic matrix elements involving the two species ofthe A' symmetry are also computed. A diabatic transforrnation is perforrned Jeading to simple geometrical depen· dences of the hyperline coupling constants.},
subject = {Organische Chemie},
language = {en}
}
@article{PericEngelsPeyerimhoff1991,
author = {Peric, M. and Engels, Bernd and Peyerimhoff, S.D.},
title = {Ab initio investigation of the vibronic structure of the C\(_2\)H spectrum Computation of the vibronically-averaged values for the Hyperfine Coupling Constants},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-58915},
year = {1991},
abstract = {The vibronically averaged values for tbe hyperfine coupling constants in the X\(^2 \sum\)-A\(^2 \Pi\) system of the ethynyl radical are computed by means of tbe ab initio metbod calculations. The results point at tbe importance of taking into account the coupling of a1l tbree electronic states in question ( I\(^2\)A', 2\(^2\)A', and 1\(^2\)A") for a reliable explanation of the available experimental findings. The mean values of the hfcc's for K = 0 and 1 levels in \(^{13}\)C\(_2\)H and \(^{13}\)C\(_2\)D in the energy range up to 6000 cm\(^{-1}\) are predicted.},
subject = {Organische Chemie},
language = {en}
}
@article{PauliMarquardtHartletal.1991,
author = {Pauli, Paul and Marquardt, Christian and Hartl, Lydia and Nutzinger, Detlef O. and H{\"o}lzl, Rupert and Strian, Friedrich},
title = {Anxiety induced by cardiac perceptions in patients with panic attack: a field study},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-61334},
year = {1991},
abstract = {In panic disorder bodily sensations appear to play an important role as a trigger for anxiety. In our psychophysiological model of panic attacks we postulate the following vicious circle: individuals with panic attacks perceive even quite small increases in heart rate and interpret these changes as being catastrophic. This elicits anxiety and a further increase in heart rate. To evaluate this model we conducted a field study of 28 subjects with panic attacks and 20 healthy controls. A 24 hr ambulatory ECG was recorded and the subjects were instructed to report any cardiac perceptions during this period and to rate the anxiety elicited by these perceptions. The incidence of cardiac perceptions was about the same in both groups, but only subjects with panic attacks reported anxiety associated with such perceptions. Analysis of the ECGs revealed that in both groups heart rate accelerations preceded cardiac perceptions. Following cardiac perceptions, the healthy controls showed a heart rate deceleration, whereas the subjects with panic attacks had a further acceleration. This heart rate increase after cardiac perceptions was positively related to the level of anxiety elicited by the perceptions. These results provide clear evidence in support of the vicious circle model of panic attacks.},
subject = {Psychologie},
language = {en}
}
@article{PauliHartlMarquardtetal.1991,
author = {Pauli, Paul and Hartl, Lydia and Marquardt, Christian and Stalmann, Henrica and Strian, Friedrich},
title = {Heartbeat and arrhythmia perception in diabetic autonomic neuropathy},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-73599},
year = {1991},
abstract = {A comparative study of diabetics with autonomic neuropathy (N = 13) as against nonneuropathic diabetics (N = 16) and healthy control persons (N = 20) was carried out with respect 10 heart rate both at rest and under stress, frequency of cardiac arrhythmias in a 24-h ECG and accuracy of heartbeat and arrhythmia perception. In the subjects with diabetic autonomic neuropathy, the spontaneaus variability and stress-induced reactivity of the heart rate as weil as the number of tachycardic episodes were reduced, whereas the frequency of ventricular extrasystoles was somewhat increased. Impaired heartbeat perception and a complete Ioss of perception of arrhythmias as a consequence of neuropathic deafferentation could be demonstrated. Cardiac perception disordersalso playavital roJe in other clinical problems, e.g. silent myocardial infarction and Iack of awareness of hypoglycaemia in diabetes mellitus.},
subject = {Psychologie},
language = {en}
}
@article{ParkkinenHackerKorhonen1991,
author = {Parkkinen, Jaakko and Hacker, J{\"o}rg and Korhonen, Timo K.},
title = {Enhancement of tissue plasminogen activator-catalyzed plasminogen activation by Escherichia coli S fimbriae associated with neonatal septicaemia and meningitis.},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-71566},
year = {1991},
abstract = {The effect of Escherichia coli strains isolated from blood and cerebrospinal fluid of septic infants on plasminogen activation was studied. These strains typically carry a filamentous surface protein, S fimbria, that has formerly been shown to bind to endothelial cells and interact with plasminogen. The bacteria effectively promoted plasminogen activation by tissue plasminogen activator (t-PA) which was inhibited by e-aminocaproic acid. A recombinant strain expressing S fimbriae accelerated t-PAcatalyzed plasminogen activation to a similar extent as did the wild-type strains whereas the nonfimbriate recipient strain had no effect. After incubation with t-PA and plasminogen, the S-fimbriate strain displayed bacterium-bound plasmin activity whereas the nonfimbriate strain did not. Bacterium-associated plasmin generation was also observed with a strain expressing mutagenized S fimbriae that Iack the cell-binding subunit SfaS but not with a strain lacking the major subunit SfaA. Both t-PA and plasminogen bound to purified S fimbriae in a lysine-dependent manner and purified S fimbriae accelerated t-PA-catalyzed plasminogen activation. The results indicate that E. coli S fimbriae form a complex with t-PA and plasminogen which enhances the rate of plasminogen activation and generates bacterium-bound plasmin. This may promote bacterial invasion and persistence in tissues and contribute to the systemic activation of fibrinolysis in septicaemia.},
subject = {Escherichia coli},
language = {en}
}
@article{OttMessnerHeesemannetal.1991,
author = {Ott, M. and Messner, P. and Heesemann, J. and Marre, R. and Hacker, J{\"o}rg},
title = {Temperature dependent expression of flagella in Legionella},
url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-59755},
year = {1991},
abstract = {Legionel/a pneumophila, the causative agent of Legionnaires' disease, was analysed by electron microscopy for production of surface structures. Crystalline surface (S-) layers and fimbriae were not detected, but monotrichous flagellation was seen. Polyclonal antibodies specific for the 47 kDa ftagellin subunit of L. pneumophila Philadelphia I were used in Western blots to confirm the presence of flagella subunits in various L. pneumophila strains tested, but the antiserumalso reacted with flagellin subunits of L. micdlulei, L. hackelia (serogroup (SG) l and SG21 and L./ongbetichae (SG2). Flagellation of Legionellae was shown to be temperature regulated. When the growth temperature of virulent and avirulent variants of strain L. pneumophila Philadelphia I was shifted from 30 oc to either 37 or 41 oc, a decrease in the percentage offtagellated bacteria within the populationwas observed.},
subject = {Infektionsbiologie},
language = {en}
}