Improvements of the Set Up and Procedures for Beam Energy Measurements at BESSY II

With a 7 T wiggler in operation all attempts to detect the resonant depolarization of the electron spins were unsuccessful at BESSY II. This was attributed to the severely reduced degree of spin polarization of the electrons moving in the alternating fields of the strong wiggler which on the other hand nearly doubles the radiation loss per turn. The key to a clear detection of the depolarization is the improvement of the sensitivity of the polarimeter, based on the spin dependent Touschek scattering cross section and the more effective and thus full depolarization of the beam. With these improvements the high precision beam energy determination can again be performed in parallel to the normal user operation and without any noticeable perturbations to the bea

Detection of autoreactive CD4 T cells using major histocompatibility complex class II dextramers

Background: Tetramers are useful tools to enumerate the frequencies of antigen-specific T cells. However, unlike CD8 T cells, CD4 T cells - especially self-reactive cells - are challenging to detect with major histocompatibility complex (MHC) class II tetramers because of low frequencies and low affinities of their T cell receptors to MHCpeptide complexes. Here, we report the use of fluorescent multimers, designated MHC dextramers that contain a large number of peptide-MHC complexes per reagent. Results: The utility of MHC dextramers was evaluated in three autoimmune disease models: 1) proteolipid protein (PLP) 139-151-induced experimental autoimmune encephalomyelitis in SJL/J (H-2s) mice; 2) myelin oligodendrocyte glycoprotein (MOG) 35-55-induced experimental autoimmune encephalomyelitis in C57Bl/6 (H-2b) mice; and 3) cardiac myosin heavy chain (Myhc)-α 334-352-induced experimental autoimmune myocarditis in A/J (H-2a) mice. Flow cytometrically, we demonstrate that IAs/PLP 139-151, IAb/MOG 35-55 and IAk/Myhc-α 334-352 dextramers detect the antigen-sensitized cells with specificity, and with a detection sensitivity significantly higher than that achieved with conventional tetramers. Furthermore, we show that binding of dextramers, but not tetramers, is less dependent on the activation status of cells, permitting enumeration of antigen-specific cells ex vivo. Conclusions: The data suggest that MHC dextramers are useful tools to track the generation and functionalities of self-reactive CD4 cells in various experimental systems

OVEREXPRESSION OF THIOREDOXIN BINDING PROTEIN (TBP-2) INCREASES OXIDATION SENSITIVITY AND APOPTOSIS IN HUMAN LENS EPITHELIAL CELLS

Thioredoxin (Trx) is an important redox regulator with cytosolic Trx1 and mitochondrial Trx2 isozymes. Trx has multi-physiological functions in cells and its bioavailability is negatively controlled through active site binding to a specific thioredoxin binding protein (TBP-2). This paper describes the delicate balance between TBP-2 and Trx, and the effect of overexpression of TBP-2 in the human lens epithelial cells. Cells overexpressing TBP-2 (TBP-2 OE) showed a 7- fold increase of TBP-2, and a nearly 40% suppression of Trx activity but no change in Trx expression. The TBP-2 OE cells grew slower and their population decreased to 30% by day 7. Cell cycle analysis showed that TBP-2 OE cells arrested at the G2-M stage, and that they displayed low expressions of the cell cycle elements P-cdc2 (Y15), cdc2, cdc25A and cdc25C. Furthermore, TBP-2 OE cells were more sensitive to oxidation. Under H2O2 (200 μM, 24 hrs) treatment, these cells lost 80% viability and became highly apoptotic. Brief oxidative stress (200 μM, 30 min) to TBP-2 OE cells disrupted the Trx anti-apoptotic function by dissociating the cytosolic and mitochondrial Trx-ASK binding complexes. The same H2O2-treated cells also showed activated ASK (P-ASK), Bax, lowered Bcl2, cytochrome c release, and elevated caspase 3/7 activities. We conclude from these studies that high cellular levels of TBP-2 can potentially suppress Trx bioavailability and increase oxidation sensitivity. Overexpression of TBP-2 also causes slow growth by mitotic arrest, and apoptosis by activating the ASK death pathway

Novel C-terminal heat shock protein 90 inhibitors target breast cancer stem cells and block migration, self-renewal, and epithelial–mesenchymal transition

In patients with triple-negative breast cancer (TNBC), evidence suggests that tumor-initiating cells (TIC) have stem cell-like properties, leading to invasion and metastasis. HSP90 plays a critical role in the conformational maintenance of many client proteins in TIC development. Therefore, we hypothesize that the novel C-terminal HSP90 inhibitors KU711 and KU758 can target TIC and represent a promising strategy for overcoming metastasis. Human breast cancer cells (MDA-MB-468LN, MDA-MB-231) treated with the HSP90 inhibitors KU711, KU758, and 17-AAG showed a 50–80% decrease in TIC markers CD44 and aldehyde dehydrogenase (P < 0.01) as assessed by flow cytometry. A decrease in sphere formation, which was used to assess self-renewal, was observed after the treatment of TNBC cells starting at 2.5 µm KU711 and 0.31 µm KU758. KU compounds also blocked the invasion and migration of TNBC cells in a dose-dependent manner. The knockdown of HSP90 clients was observed without any change in prosurvival HSP70 levels. In vivo, in a murine orthotopic breast cancer model, treatment with KU758 and KU711 yielded an approximately twofold and a fourfold reduction in tumor volumes versus control, respectively, without demonstrated toxicity. In conclusion, C-terminal HSP90 inhibitors are potent novel therapeutics against TNBC in vitro and in vivo as they target TICs and block invasion, EMT transition, and self-renewal

Nonverbal communication in intergenerational interactions

Diese Arbeit zielt darauf ab, Einblicke in die Kommunikation intergenerationaler Interaktionen zu erhalten, indem die Koordination zwischen jungen und älteren Erwachsenen betrachtet wird. Interpersonale Koordination beeinflusst Interaktionen positiv, deshalb ist die Koordination zweier Menschen der Fokus dieser Arbeit, wobei insbesondere die Abhängigkeit interpersonaler Koordination von bestimmten Kontextfaktoren studiert wird. Die Arbeit versteht die emotionale und behaviorale Mimikry, und die Synchronität zweier Interaktionspartner als Aspekte interpersonaler Koordination. Hierfür wurden mehrere Studien zur Analyse von emotionaler Mimikry (Studie 1), Synchronität und behavioraler Mimikry (Studie 2) durchgeführt. Außerdem wurde eine Zugehörigkeitsmotivation gegenüber Älteren experimentell erzeugt und anschließend emotionale Mimikry erhoben (Studie 3). Für Studien 1 und 2 interagierten junge Probanden mit einer älteren oder einer gleichaltrigen Person, die ein freudiges oder ärgerliches Ereignis erzählte. Studie 1 zeigte, dass freudige Gesichtsausdrücke immer imitiert wurden, insbesondere innerhalb gleichaltriger Interaktionen und während der freudigen Erzählung. Studie 2 zeigte mehr Synchronität innerhalb gleichaltriger als bei nicht-gleichaltrigen Interaktionen, während mehr behaviorale Mimikry bei älteren als bei jungen Interaktionspartnern gefunden wurde. Darüber hinaus veranschaulichte Studie 3, dass eine erhöhte Zugehörigkeitsmotivation gegenüber einer älteren Person das Imitiationsverhalten gegenüber der gesamten Altersgruppe positiv beeinflusste. Die Arbeit verschafft einen Einblick in intergenerationale Interaktionen, deren Ergebnisse nahelegen, dass obwohl junge Menschen generell motiviert sind mit älteren Menschen zu interagieren, bestimmte Umstände sie davon abhalten können. Allerdings konnten wir mit der Manipulation der Zugehörigkeitsmotivation einen vielversprechenden Ausblick für intergenerationale Kommunikation schaffen.This dissertation aims to unravel intergenerational communication by studying interpersonal coordination between young and older adults. Interpersonal coordination is considered to have a positive influence on interactions. Thus, this work sets out to determine whether interpersonal coordination depends on contextual factors such as the social relation context and the affective context. Several studies were conducted to assess three aspects of interpersonal coordination: Emotional mimicry (Study 1), synchrony and behavioral mimicry (Study 2). Moreover, as it was hypothesized that young adults are not motivated to affiliate with the elderly, a heightened affiliation motivation toward the elderly was experimentally created and emotional mimicry assessed subsequently (Study 3). For studies 1 and 2, young adults were invited to interact with an elderly person or with a person of the same age who recounted an emotional (happy or angry) event. Study 1 revealed mimicry of happiness expressions, particularly within same-generation interactions and during the narration of a happy event, while angry expressions were rarely displayed and not mimicked. Study 2 revealed more synchrony within same-generation compared to intergenerational interactions, whereas there was more behavioral mimicry of elderly interaction partners compared to young interaction partners. Study 3 illustrated that a heightened motivation toward an older person positively influenced mimicking behavior toward the whole age group. This dissertation provides a first step in unravelling intergenerational interactions, where findings regarding emotional mimicry and synchrony suggest that certain circumstances might prevent young adults from acting the same toward young and old individuals. However, as we were able to successfully manipulate affiliation motivation, a promising positive outlook for intergenerational communication emerged