Superantigen-induzierte Effekte auf die Expression des IL-2 Rezeptors und Proliferation von CD4- und CD8-positiven T-Zellen in der Ratte

Die Bindung bakterieller Superantigene (SAg) an T-Zellen mit spezifischen Vb-Isotypen in ihrem Rezeptor führt zu einer polyklonalen Aktivierung zahlreicher T-Lymphozyten. Im humanen System sind SAg die häufigste Ursache von Lebensmittelvergiftungen, welche einhergehen mit einem hohen Risiko des septischen Schocks. Bei Mäusen ist die immunstimulierende Wirkung der SAg hinreichend untersucht, wohingegen nur wenig bei Ratten bekannt ist. Die vorliegende Arbeit hat zum Ziel, die immunstimulatorische Wirkung von Staphylokokken Enterotoxin A (SEA) auf Lymphozyten verschiedener Immunorgane der Ratte in vivo zu charakterisieren. Hierüber liegen bisher keine systematischen Studien in der Literatur vor. Das Serum sowie die lymphatischen Organe (Milz, Thymus, mesenteriale Lymphknoten) wurden zu verschiedenen Zeitpunkten nach SEA-Applikation entnommen. Erhöhte IL-2 und IL-6 Serumspiegel zeigten den starken immunstimulatorischen Effekt von SEA. Die Lokalisation von IL-2 Rezeptor alpha mRNA mittels in-situ Hybridisierung in der periarteriolären lymphatischen Scheide (PALS) der Milz, einer Region, in der hauptsächlich T-Lymphozyten als Zelltyp vorliegen, unterstreicht die T-Zell-mediierte Immunstimulation. Die Laser-Capture-Microdissection (LCM) der PALS zeigte stark erhöhte IL-2 Rezeptor alpha mRNA Spiegel gemessen in der PCR, im Vergleich zu anderen Regionen der Milz. Signifikant erhöhte Zahlen von CD4+ als auch CD8+ Lymphozyten, die zusätzlich die IL-2 Rezeptor a-Kette (CD25) auf ihrer Oberfläche exprimierten, wurden in der FACS-Analyse gemessen. Der erwartete starke mitogene Effekt von SEA auf die IL-2 Rezeptor positiven Zellen wurde durch hohe Proliferationsraten von Splenozyten, Thymozyten und auch Zellen des mesenterialen Lymphknoten gezeigt. Insgesamt läßt sich SEA, in Homologie zum humanen Organismus, als ein potentes Mitogen für das periphere Immunsystem der Ratte charakterisieren

Standard Giant Branches in the Washington Photometric System

We have obtained CCD photometry in the Washington system C,T1 filters for some 850,000 objects associated with 10 Galactic globular clusters and 2 old open clusters. These clusters have well-known metal abundances, spanning a metallicity range of 2.5 dex from [Fe/H]~-2.25 to +0.25 at a spacing of ~0.2 dex. Analogous to the method employed by Da Costa and Armandroff (1990, AJ, 100, 162) for V,I photometry, we then proceed to construct standard giant branches for these clusters. The Washington system technique is found to have three times the metallicity sensitivity of the V,I technique. Thus, for a given photometric accuracy, metallicities can be determined three times more precisely with the Washington technique. We find a linear relationship between (C-T1)o (at M(T1)=-2) and metallicity (on the Zinn 1985, ApJ, 293, 424 scale) exists over the full metallicity range, with an rms of only 0.04 dex. We also derive methods to determine distance, reddening and metallicity simultaneously, and note that the Washington system holds great potential for deriving accurate ages as well.Comment: To be published in the 1999 AJ January issu

Phase stability of chromium based compensated ferrimagnets with inverse Heusler structure

Chromium based inverse Heusler compounds of the type Cr2YZ (Y=Co, Fe; Z=Al, Ga, In, Si, Ge, Sn) have been proposed as fully compensated half-metallic ferrimagnets. Such materials are of large interest for spintronics because they combine small magnetic moment with high spin polarization over a wide temperature range. We assess their thermodynamic stability by their formation enthalpies obtained from density functional theory calculations. All compounds under investigation are unstable. Cr2FeSi and Cr2CoAl are stable with respect to the elemental constituents, but decompose into binary phases. Cr2FeGe, Cr2CoGa, Cr2FeSn and Cr2CoIn are found to be unstable with respect to their elemental constituents. We identify possible binary decompositions.Comment: 3 pages, 1 figure, 2 table

Against all odds: fathers’ use of parental leave in Germany

This paper investigates fathers’ usage of parental leave in Germany based on data from the microcenses 1999-2005. We consider two competing hypotheses. On the one hand, we argue that value change is a driving force behind fathers’ engagement in parenting activities. We assume that the ‘new father’ can more often be found among highly educated and urban men who are believed to be the forerunners in terms of new values and ideas. We contrast this hypothesis with the assumption that economic factors are the main determinants of men’s parental leave decisions. Our main finding is that fathers are more likely to be on parental leave if they have a highly educated or older partner. We also find that employment through a temporary working contract substantially lowers the chances that men will take advantage of parental leave, while being employed in the public sector increases the chances that men will use their parental leave entitlement.Germany, employment

A pollen study of thirty-two species of grasses

The study of fossil pollens from bogs and lake sediments shows that sometimes the percentage of grasses runs quite high. The presence of large amounts of grass pollens has usually been interpreted, often without justification, as proof of prairie invasion. It is certainly necessary to determine the genera of grasses which contributed the pollen before such a conclusion can be made. Keller (5) attempted this in his work on three Indiana bogs. Careful examination and measurements of the grass pollens found and comparison with size frequency of pollens from modern grasses forced him to the conclusion that the predominating pollen present in the bogs was that of Calamagrostis canadensis and not of prairie species. For that reason it has no diagnostic value as an indicator of a xerothermic period in northern Indiana

Postoperative pain management after total hip arthroplasty. A focus on evidence, clinical practice and the individual patient’s pain response.

Background: Patients experiencing high levels of pain after surgery remains a considerable clinical problem. Often, no consensus about the best analgesic treatment is present. The majority of clinical trials regarding postoperative pain, generally, target the average analgesic efficacy. In terms to step forward, a focus on the individual patients´ pain levels is needed and an identification of the patients in risk of developing higher postoperative pain levels.Aim: The overall aim was to explore the pain management for total hip arthroplasty (THA) patients by investigating the evidence in the literature, and the manifestation in clinical practice, including a focus on the individual patient and possible predictive tools.Methods: A systematic review was conducted investigating the different analgesic treatments in randomised clinical trials (RCT) regarding THA patients (Study I). To investigate the analgesic efficacy at the individual patient level, in terms of obtaining, ‘no worse than mild pain / VAS ≤30, a re-analysis was performed which included individual patient data of previous RCTs (Study II). The effect of multimodal analgesic treatment in THA patients in clinical practice was mapped in a large multicenter cohort study at five different hospitals (Study III). Finally, we investigated if four different and simple approaches were able to predict high levels of pain postoperatively: pain during peripheral venous cannulation (PVC), highest pain levels at the Post Anaesthesia Care Unit (PACU), PACU nurses prediction, and patient’s forecast. (Study IV).Results: In the systematic review, we found that the literature regarding the analgesic treatment for THA was heterogeneous and with no “gold standard”. The re-analysis demonstrated, based on the success criteria 80% should obtain VAS-pain ≤30, at 6 and 24hr postoperatively, half of the patients succeeded reaching the goal at rest. During mobilisation only 14-15% obtained the goal. The multicenter study demonstrated large differences in the analgesic treatment between hospitals. Surprisingly, did the patients´ pain levels not differ much, no matter which kind of analgesic treatment they had received, neither at a hospital-level nor at an individual patient level.None of the four predictive tools showed efficacy in predicting high pain responders at 24hr postoperatively during mobilisation.Conclusions: The literature regarding analgesic treatment for THA is heterogenic with no “gold standard.” When re-analysing 16 previous RCTs we found insufficient pain treatment at the individual patient level, especially during mobilisation. The pain treatment for THA at five different hospitals differed a lot. No matter how complex the multimodal pain was, patients´ outcomes were very similar according to pain and side effects. PVC-pain preoperatively could not be used as a predictive tool for patients with high pain levels after 24hr during mobilisation postoperatively. That was also the findings with PACU nurses prediction, highest pain levels at the PACU and patients forecas

Can 'nothing' be grammaticalised? Comments on Permian vowel ~ zero alternations

The aim of this paper is to present the most salient characteristics of Permian vowel ~ zero alternations and to analyse them in terms  of grammaticalisation. The term `grammaticalisation' will be used here in a non-traditional sense. When we investigate grammaticalisation, it is not merely individual linguistic units (having turned into grammatical ones), but also relationships between linguistic units that are to be taken into consideration. If, for instance, a phonological relationship that originally obtained between certain forms and triggered the application of some automatic process turns into a non-automatic alternation that distinguishes linguistic units from one another, this is just as much an instance of grammaticalisation as the well-known cases in which an originally lexical item turns into a grammatical one. This hypothesis will be substantiated in this paper with the help of some considerations concerning Permian vowel ~ zero alternations