Release of prostaglandin D2 by murine mast cells: importance of metabolite formation for antiproliferative activity.

Prostaglandin (PG) D2, PGJ2 and delta12-PGJ2 are antiproliferative eicosanoids. We investigated the production of PGD2 by murine bone marrow-derived mast cells (BMMC) taking into consideration metabolism of PGD2 to PGD2 and delta12-PGJ2. PG-metabolites were quantified by high performance liquid chromatography (HPLC) combined with radioimmunoassay (RIA). Stimulated with calcium ionophore A23187 BMMC released eight-fold more PGJ2 and delta12-PGJ2 than PGD2. Conversion of endogenously produced PGD2 to PGJ2 and delta12-PGJ2 proceeded rapidly in contrast to metabolism of exogenously added PGD2. The antiproliferative potency of these prostaglandins is demonstrated in vitro. We conclude that determination of PGD2 production by mast cells must take into consideration rapid conversion to active derivatives, which may play a significant role in growth regulation

Überforderungsgefühle oder subjektiver Kompetenzerwerb - Wie bewerten Studierende der Tiermedizin ihre kurativen Praktika?

Veterinary studies in Germany are regulated by the Veterinary Certification Act (TAppV). The practical part of the education consists of 1,170 hours, whereby up to 850 hours can be spent on the curative work placement. A curative work placement can result in physical and psychological stress in the sense of a professional overload. It is the aim of this study to find out in what areas and to what extent competence is acquired and psychological stress exists in students during their work placement. Veterinary students (n=142) from all German education institutes participated in a voluntary online-study based on Burnout Screening Scales (BOSS) as well as a questionnaire regarding the acquisition of competence and excessive stress during the work placement (FKÜP). The distribution of values for work placement related stress show that such work placement related stress is generally slightly increased (T=60) and lies above that of occupational stresses within the normal population. Work placement related physical complaints also show a significant slight increase (T=61). A value (T=42) within the normal range was determined for the resource values. Few of the students questioned considered themselves to be excessively stressed in favour of a high subjective acquisition of competences. The largest increase regarding the acquisition of competence was noted for the areas of animal handling/restraint and application and injection techniques. In the sense of a perceived excessive demand regarding practical capabilities the areas of emergency management, surgery and medication dispensation were mentioned. With regard to the load structure and the acquisition of competence by veterinary students during their work placement, more support of the individual and a balancing of teaching/learning goals would be desirable and represents a promising approach.In Deutschland ist das Tiermedizinstudium durch die Tierärztliche Approbationsverordnung (TAppV) geregelt. Der praktische Anteil der Ausbildung beträgt 1.170 Stunden, wobei bis zu 850 Stunden in kurativen Praktika absolviert werden. In kurativen Praktika kann es zu physischen und psychischen Belastungen im Sinne einer Arbeitsüberforderung kommen. Ziel dieser Studie soll es sein herauszufinden, in welchen Bereichen und in welchem Umfang Kompetenzen erworben und psychische Belastungen bei Studierenden im Praktikum vorhanden sind. An einer freiwilligen Online-Umfrage, basierend auf Burnout-Screening-Skalen (BOSS) sowie einem Fragebogen zum Kompetenzerwerb und Überforderungen im Praktikum (FKÜP), nahmen Tiermedizinstudierende (n=142) aller deutschen Bildungsstätten teil. Die Verteilung der Werte für praktikumsbezogene Belastungen zeigen, dass praktikumsbezogene Belastungen im Mittel signifikant leicht erhöht (T=60) sind und oberhalb der beruflichen Belastungen der Normalpopulation liegen. Ebenfalls sind die praktikumsbezogenen Beschwerden auf körperlichen Ebene signifikant leicht erhöht (T=61). Für die Ressourcenwerte wurde ein Wert (T=42) innerhalb des Normalbereiches ermittelt. Dabei schildern die befragten Studierenden wenige Überforderungsgefühle zu Gunsten eines hohen subjektiven Kompetenzerwerbs. Für die Bereiche Umgang mit Tieren, Zwangsmaßnahmen sowie Applikations- und Injektionstechniken konnten die größten Zuwächse beim Kompetenzerwerb ermittelt werden. Im Sinne eines Überforderungsgefühls bei praktischen Fertigkeiten wurden die Bereiche Notfallmanagement, Chirurgie und Medikamentenabgabe genannt. Bezogen auf die Belastungsstruktur und den Kompetenzerwerb von Studierenden der Tiermedizin im Praktikum ist mehr Förderung der einzelnen Person und ein Abgleich von Lehr-/Lernzielen wünschenswert und ein vielversprechender Ansatz

Tetradehydroadamantane-1,3,5,7-di- and tetracations and their helium and hydride inclusion complexes: Spherical aromaticity and evidence for a bonding interaction between carbon and helium

The unusual stability of the experimentally known 1,3-dehydro-5,7-adamantyl dication was previously explained by four-center two-electron aromaticity with three-dimensional (tetrahedral) topology. Magnetic criteria (ACID and ring-current analysis) now demonstrate that there is also a very strong contribution from hyperconjugation with all six methylene bridges. The delocalized system of electrons thus includes all valence electrons, and the structure, therefore, should rather be described as a spherically aromatic 50-electron system. The corresponding T-d-symmetric tetracation with 48 electrons is antiaromatic and not a minimum structure. With a He atom or a hydride ion at the center of the cage, the tetracation is predicted to form a kinetically stable complex. Magnetic criteria demonstrate that the antiaromaticity is greatly reduced, and a bond analysis hints at bonding interactions between He (and H-) and the carbon atoms of the adamantane cage