Racemization and hydrolysis of tropic acid alkaloids in the presence of cyclodextrins

Because of the constantly increasing demand for optically pure drugs it is of great importance to elucidate factors affecting stereochemistry, in order to provide a stable formulation with a high chiral quality of the desired isomer. Therefore, the effects of cyclodextrins (CyDs) and their alkylated and hydroxyalkylated derivatives on racemization and hydrolysis of (?)-(S)-hyoscyamine and (?)-(S)-scopolamine were examined kinetically and spectroscopically (NMR). Direct methods, based on a chiral and achiral chromatographic phase system, were used to determine their degradation products and enantiomer composition during stability tests. All different CyDs, except α-CyD, retarded racemization and hydrolysis. The inclusion of the drug substances in CyDs inhibits the attack of hydroxyl ions and/or water molecules and thus retards the racemization and hydrolysis. The racemization of the tropic acid alkaloids is dependent on the pH and temperature. NMR studies were used to evidence the formation of a soluble 1:1 complex in aqueous solution. © 1993 Wiley-Liss, Inc.     

Zur Brutbiologie des Schilfrohrs?ngers,Acrocephalus schoenobaenus L

Ohne Zusammenfassung     

Erster Brutnachweis des Bindenkreuzschnabels (Loxia leucoptera) in Mitteleuropa

Zusammenfassung Der Bindenkreuzschnabel (Loxia leucoptera) brütete 1991 in einem Paar erfolgreich auf einem Berliner Friedhof und damit erstmals sicher in Mitteleuropa. Zwei Jungvögel wurden am 29. Mai flügge. Die Baumschicht des Friedhofs besteht zu 80 % aus Laubholz und nur zu 20 % aus Nadelholz, d. h. die Art wählte hier den offenen, gemischten Laubwaldtyp. Dieser Nachweis ist mit einer sehr großen Invasion von Kreuzschnäbeln nach Mittel- und Westeuropa in Verbindung zu bringen. Einige die bisherigen Erkenntnisse ergänzende Beobachtungen werden zu Gefiedermerkmalen, Verhalten und stimmlichen Äußerungen mitgeteilt.

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First breeding record of Two-barred Crossbill (Loxia leucoptera) in Central Europe

Summary In 1991, a pair of Two-barred Crossbills bred successfully on a cemetery of Berlin, which is the first certain breeding record in Central Europe of this species. Two young fledged May 29. The tree stand of the cemetery consists of 80 % deciduous trees and 20 % conifers only, which means the selection of an open, mixed deciduous forest type. This event has to be seen in connection with a very intense invasion of Crossbills to Central and Western Europe. Some notes are given on plumage characters, behaviour and vocalizations.

     

Nucleotide sequence of the Wolinella succinogenes flagellin, which contains in the antigenic domain two conserved regions also present in Campylobacter spp. and Helicobacter pylori.

Wolinella succinogenes possesses one polar flagellum, which shows a characteristic surface pattern of parallel lines along the axis of the filament in electron microscopic images. We determined the gene sequence of the Wolinella flagellin, which is, as in most other bacteria, the only structural component of the filament. Sequence comparison with other members of the Proteobacteria revealed two highly conserved regions in the central part of the flagellin molecule among Campylobacter spp. and Helicobacter pylori, an area that had previously been described as highly variable. Similar surface patterns are found in related polarly flagellated bacteria, but not in Escherichia coli and Bacillus subtilis, which also lack these conserved regions.     

Untersuchungen über die immunhistochemische Fibrindarstellung an Biopsie- und Obduktionsmaterial

Zusammenfassung Mit Hilfe der direkten immunhistochemischen Methode ist ein spezifischer Fibrinnachweis möglich. Um die praktische Anwendung der Methode für wissenschaftliche und diagnostische Fragestellungen der Humanpathologie zu prüfen, bei der in der Regel kein Frischgewebe zur Verfügung steht, wurden Untersuchungen an unterschiedlich altem und unterschiedlich vorbehandeltem Biopsie- und Obduktionsmaterial durchgeführt. Dabei zeigt sich, daß die Antigenität des Fibrins sehr stabil ist und auch postmortal lange erhalten bleibt, so daß die Methode für den Fibrinnachweis auch am Obduktionsmaterial gut geeignet ist.

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Summary A specific demonstration of fibrin was made possible by means of a direct immunohistochemical method. To test its use for scientific and diagnostic problems in human pathology — for which, as a rule, fresh material is not available — tests were carried out on material obtained by biopsy and autopsy (Tissues of various age and different pre-treatment). It was possible to demonstrate that the antigenicity of fibrin is maintained over long periods. The method is therefore especially suitable for the demonstration of fibrin in post mortem material.

     

On the population genetics of the ceruloplasmin polymorphism

Summary The frequencies of Cp-variants in 3 European, 1 Asiatic and 3 African populations are reported. The most striking fact is the high incidence of the Cp^A-allele not only in the African but also in 2 European samples.

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Zusammenfassung An 3 europäischen, 1 asiatischen und 3 afrikanischen Stichproben werden die populationsgenetischen Daten von Coeruloplasmin-Varianten erhoben. Der auffallendste Befund ist die erhöhte Cp^A-Frequenz nicht nur in den afrikanischen, sondern auch in 2 europäischen Stichproben.

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Supported by the Deutsche Forschungsgemeinschaft.     

Further studies on the AB0-typing of ancient bones

Summary This paper deals with the AB0-typing of bone material from the 14th century. From 151 femora, 126 gave a positive reaction, the rest did not react at all. 53.9% A, 16.7% B, 23.8% H and 5.6% AB are the respective results. Some hypotheses suggesting relations between infectious diseases and AB0 blood groups are discussed. The AB0 distribution seems to point to an association with plague and smallpox.

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Zusammenfassung In der vorliegenden Untersuchung werden die Ergebnisse einer AB0-Bestimmung an Knochenmaterial aus dem 14. Jahrhundert mitgeteilt. 126 von 151 Femoral, die zur Bestimmung gelangten, zeigten eine positive Reaktion: 53,9% A, 16,7% B, 23,8% H und 5,6% AB wurden in dieser Stichprobe gefunden. In diesem Zusammenhang werden einige Hypothesen diskutiert, die eine Beziehung zwischen Infektionskrankheiten, vor allem Pest und Pocken, und AB0-Blutgruppen nahelegen.

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Supported by the Deutsche Forschungsgemeinschaft.     

Macromolecular complexes of aminoacyl-tRNA synthetases from eukaryotes. 1. Extensive purification and characterization of the high-molecular-weight complex(es) of seven aminoacyl-tRNA synthetases from sheep liver.

Starting from homogenates of sheep liver, extensive co-purification of seven aminoacyl-tRNA synthetases to high specific activities was achieved by a three-step procedure involving fractional precipitation by poly(ethylene glycol) 6000, gel filtration on 6% agarose and chromatography on Sepharose-bound tRNA. The purified material is composed of nine major protein components as revealed by polyacrylamide gel electrophoresis in the presence of sodium dodecyl sulfate and has an apparent molecular weight of about 10(6) estimated by gel filtration on 6% agarose. It contains aminoacyl-tRNA synthetase activities specific for methionine, lysine, arginine, leucine, isoleucine, glutamine and glutamic acid. The rigorous co-elution of these seven enzymes at each chromatographic step suggests, but does not conclusively prove, that they are physically associated within the same complex. The enzyme composition of the high-molecular-weight complex purified from sheep liver is identical to that of the complex previously isolated from human placenta by Denney in 1977 (Arch. Biochem. Biophys. 183, 156--167).     

Der statische Sinn der Medusen

Ohne Zusammenfassung