Therapie und Diagnostik von neuroendokrinen Tumoren in der Chirurgischen Klinik der Universität München

Neuroendokrine Tumore (NET) stellen mit einem Anteil von 0,5% an allen Tumorerkrankungen eine seltene Tumorgruppe dar, deren Inzidenz jedoch stetig zunimmt. Bezüglich ihres biologischen Verhaltens, Diagnostik, Therapie und Prognose unterscheiden sie sich erheblich von Tumoren epithelialen Ursprungs. Sie können in Behandlungszentren interdisziplinär durch ein breites therapeutisches Konzept behandelt werden. Aufgrund der besseren Prognose resultieren meist lange Krankheitsverläufe, die eine medizinische Herausforderung darstellen können. In der vorliegenden Arbeit werden die Erfahrungen der Chirurgischen Klinik Großhadern mit 136 Patienten mit NET von Lunge, Pankreas, Appendix, Magen und Duodenum dargestellt. Analysiert wurden Tumorinzidenz, der klinische Verlauf, Diagnostik- und Behandlungsmodalitäten sowie das Outcome über 15 Jahre

Mechanismus der funktionell relevanten Kopplung von Kontaktallergenen in dendritischen Zellen

Über die Signaltransduktion in Langerhanszellen, den antigenpräsentierenden Zellen der Epidermis, ist bisher nur wenig bekannt. Mit ein Grund dafür ist die schlechte Verfügbarkeit reiner Langerhanszellen aufgrund ihrer geringen Zahl und der schwierigen Präparation, die häufig schon zur Voraktivierung dieser Zellen führt. Humane unreife und reife dendritische Zellen erwiesen sich als geeignete Modellzellpopulation für kutane antigenpräsentierende Zellen. Mit Hilfe dieser Modellzellen wurde die Beteiligung von zentralen Signaltransduktionswegen nach Interaktion mit dem Kontaktallergen TNCB untersucht. 1. Zum ersten Mal wird gezeigt, dass TNCB in den ersten 10 Minuten nach der Haptenisierung bei dendritischen Zellen intrazellulär lokalisiert ist. Die Stimulation von DC mit dem starken Kontaktallergen TNCB führte zu einer Aktivierung der ERK1/2 MAP Kinase. Dieses Ergebnis entspricht der Vorstellung, dass starke Kontaktallergene in subtoxischen Konzentrationen zellulären Streß bei MAP Kinasen auslösen und somit zu einer für die Kontaktallergie typischen Antigenpräsentation führen. 2. Die Tyrosinphosphorylierung wurde bereits in vorausgegangenen Arbeiten (Kuhn, 1998; Brand, 2002) als Charakteristikum für haptenbehandelte Monozyten und humane dendritische Zellen herausgestellt. Diese Ergebnisse konnten mit humanen unreifen und reifen DC weitergeführt werden. Proteinbiochemisch ergab das Kontaktallergen TNCB ein spezifisches und reproduzierbares Muster hyperphosphorylierter Proteinbanden. Der gemessene Anstieg an Phosphotyrosin beruhte auf der gesteigerten Aktivität von Protein Tyrosin-Kinasen. 3. In weiteren Untersuchungen wurden Proteine massenspektrometrisch analysiert, die tyrosinphosphoryliert waren und gleichzeitig TNCB gebunden hatten. Es wurden drei Proteine identifiziert: Gewebstransglutaminase bei 74-80kD, Thyroidhormon Bindeprotein bei 58kD und Aktin bei 38kD. Nach Literaturrecherchen war die Transglutaminase am vielversprechendsten und wurde auf ihre Aktivität innerhalb der Kontaktallergen-induzierten Signaltransduktionskaskade hin untersucht. Drei strukturell verschiedene Stoffe, das Kontaktallergen TNCB, die Retinsäure (RA) und ein Phorbolester (PMA) induzierten eine starke, proteinbiochemisch meßbare Tyrosinphosphorylierung der ERK1/2 MAP Kinase. Aus der Literatur war die RA für eine Aktivierung der tTG bekannt (Antonyak et al., 2002) und PMA als Stimulator der ERK1/2 MAP Kinase (Chen et al., 2002; Lee et al., 2002) - aus diesem Grund wurden sie als Positivkontrolle mitgeführt. 4. Mittels Immunpräzipitation wurde der Nachweis, dass TNCB an die tTG bindet, erbracht. Dies war der erste Indikator für eine Bedeutung der tTG als Zielstruktur für ein Kontaktallergen. 5. TNCB, RA und PMA lösen eine gesteigerte Transamidierungsaktivität der tTG aus, die essentiell zur Induktion der ERK-Phosphorylierung ist. Dies wurde durch einen Transamidierungs Aktivitäts Assay bestimmt (Zhang et al., 1998), einem Nachweis der tTG Aktivität mittels Inkorporation von biotinylierten Polyaminen in lokale Proteine. 6. Sowohl die tTG Aktivität als auch die ERK-Phosphorylierung nach TNCB Stimulation konnten durch den spezifischen Inhibitor der Transamidierungsaktivität der tTG MDC gehemmt werden. Dies war ein zweiter Hinweis, dass die enzymatische Aktivität der tTG eine große Rolle spielt. Das gleichzeitige Ausbleiben der Transamidierung und der ERK-Phosphorylierung deutet auf den deutlichen Einfluß der tTG auf den Signaltransduktionsweg der ERK1/2 MAP Kinase hin. Analysen mit anderen starken Kontaktallergenen, wie z.B. Thiomersal und Chlormethylisothiazolon/ Methylisothiazolon bieten zukünftige Forschungsansätze zur weiteren Charakterisierung der funktionellen Bedeutung der tTG und des ERKWeges. Interessant wären auch Untersuchungen zur Hochregulation der tTGExpression in DC von 24-72 Stunden nach einer Inkubation mit TNCB, RA und PMA. Auch sind weitere Untersuchungen zur Signaltransduktionskaskade im Hinblick auf die erforderlichen, nachgeschalteten Elemente interessant, wie z.B. der von der tTG aktivierten Protein B Kinase AKT (Antonyak et al., 2002) sowie beteiligter Kinasen des ERK-Weges

Effect of Conformation of Sugar Beet Pectin on the Interfacial and Emulsifying Properties

The influence of the conformation of sugar beet pectin (SBP) on the interfacial and emulsifying properties was investigated. The colloidal properties of SBP, such as zeta potential and hydrodynamic diameter, were characterized at different pH levels. Furthermore, pendant drop tensiometry and quartz crystal microgravimetry were used to study adsorption behavior (adsorbed mass and adsorption rate) and stabilizing mechanism (layer thickness and interfacial tension). A more compact conformation resulted in a faster reduction of interfacial tension, higher adsorbed mass, and a thicker adsorption layer. In addition, emulsions were prepared at varying conditions (pH 3–5) and formulations (1–30 wt% MCT oil, 0.1–2 wt% SBP), and their droplet size distributions were measured. The smallest oil droplets could be stabilized at pH 3. However, significantly more pectin was required at pH 3 compared to pH 4 or 5 to sufficiently stabilize the oil droplets. Both phenomena were attributed to the more compact conformation of SBP at pH < pK$_{a}$: On the one hand, pectins adsorbed faster and in greater quantity, forming a thicker interfacial layer. On the other hand, they covered less interfacial area per SBP molecule. Therefore, the SBP concentration must be chosen appropriately depending on the conformation

Evidence for a Pathophysiological Role of Keratinocyte-Derived Type III Interferon (IFNλ) in Cutaneous Lupus Erythematosus

Type I IFNs (IFNα/β) have been shown to have a central role in the pathophysiology of lupus erythematosus (LE). The recently discovered type III IFNs (IFNλ1/IL29, IFNλ2/IL28a, IFNλ3/IL28b) share several functional similarities with type I IFNs, particularly in antiviral immunity. As IFNλs act primarily on epithelial cells, we investigated whether type III IFNs might also have a role in the pathogenesis of cutaneous LE (CLE). Our investigations demonstrate that IFNλ and the IFNλ receptor were strongly expressed in the epidermis of CLE skin lesions and related autoimmune diseases (lichen planus and dermatomyositis). Significantly enhanced IFNλ1 could be measured in the serum of CLE patients with active skin lesions. Functional analyses revealed that human keratinocytes are able to produce high levels of IFNλ1 but only low amounts of IFNα/β/γ in response to immunostimulatory nuclear acids, suggesting that IFNλ is a major IFN produced by these cells. Exposure of human keratinocytes to IFNλ1 induced the expression of several proinflammatory cytokines, including CXCL9 (CXC-motiv ligand 9), which drive the recruitment of immune cells and are associated with the formation of CLE skin lesions. Our results provide evidence for a role of type III IFNs in not only antiviral immunity but also autoimmune diseases of the skin

The role of demonstrator familiarity and language cues on infant imitation from television

An imitation procedure was used to investigate the impact of demonstrator familiarity and language cues on infant learning from television. Eighteen-month-old infants watched two pre-recorded videos showing an adult demonstrating a sequence of actions with two sets of stimuli. Infants' familiarity with the demonstrator and the language used during the demonstration varied as a function of experimental condition. Immediately after watching each video, infants' ability to reproduce the target actions was assessed. A highly familiar demonstrator did not enhance infants' performance. However, the addition of a narrative, developed from mothers' naturalistic description of the event, facilitated learning from an unfamiliar demonstrator. We propose that the differential effect of demonstrator familiarity and language cues may reflect the infants' ability to distinguish between important and less important aspects in a learning situation. (C) 2010 Elsevier Inc. All rights reserved

South Atlantic intermediate water advances into the North-east Atlantic with reduced Atlantic meridional overturning circulation during the last glacial period

The Nd isotopic composition (epsilon Nd) of seawater and cold-water coral (CWC) samples from the Gulf of Cadiz and the Alboran Sea, at a depth of 280-827 m were investigated in order to constrain middepth water mass dynamics within the Gulf of Cadiz over the past 40 ka. epsilon Nd of glacial and Holocene CWC from the Alboran Sea and the northern Gulf of Cadiz reveals relatively constant values (-8.6 to -9.0 and -9.5 to -10.4, respectively). Such values are similar to those of the surrounding present-day middepth waters from the Mediterranean Outflow Water (MOW; epsilon Nd approximate to -9.4) and Mediterranean Sea Water (MSW; epsilon Nd approximate to -9.9). In contrast, glacial epsilon Nd values for CWC collected at thermocline depth (550-827 m) in the southern Gulf of Cadiz display a higher average value (-8.90.4) compared to the present-day value (-11.70.3). This implies a higher relative contribution of water masses of Mediterranean (MSW) or South Atlantic origin (East Antarctic Intermediate Water, EAAIW). Our study has produced the first evidence of significant radiogenic epsilon Nd values (approximate to -8) at 19, 23-24, and 27 ka, which are coeval with increasing iceberg discharges and a weakening of Atlantic Meridional Overturning Circulation (AMOC). Since MOW epsilon Nd values remained stable during the last glacial period, it is suggested that these radiogenic epsilon Nd values most likely reflect an enhanced northward propagation of glacial EAAIW into the eastern Atlantic Basin

Pushing the boundaries: Glacial/interglacial variability of intermediate and deep waters in the southwest Pacific over the last 350,000 years

Glacial/interglacial changes in Southern Ocean's air-sea gas exchange have been considered as important mechanisms contributing to the glacial/interglacial variability in atmospheric CO2. Hence, understanding past variability in Southern Ocean intermediate to deep water chemistry and circulation is fundamental to constrain the role of these processes on modulating glacial/interglacial changes in the global carbon cycle. Our study focused on the glacial/interglacial variability in the vertical extent of southwest Pacific Antarctic Intermediate Water (AAIW). We compared carbon and oxygen isotope records from epibenthic foraminifera of sediment cores bathed in modern AAIW and Upper Circumpolar Deep Water (UCDW; 943-2066 m water depth) to monitor changes in water mass circulation spanning the past 350,000 years. We propose that pronounced freshwater input by melting sea ice into the glacial AAIW significantly hampered the downward expansion of southwest Pacific AAIW, consistent with climate model results for the Last Glacial Maximum. This process led to a pronounced upward displacement of the AAIW-UCDW interface during colder climate conditions and therefore to an expansion of the glacial carbon pool

Deconvolution of complex G protein–coupled receptor signaling in live cells using dynamic mass redistribution measurements

Label-free biosensor technology based on dynamic mass redistribution (DMR) of cellular constituents promises to translate GPCR signaling into complex optical 'fingerprints' in real time in living cells. Here we present a strategy to map cellular mechanisms that define label-free responses, and we compare DMR technology with traditional second-messenger assays that are currently the state of the art in GPCR drug discovery. The holistic nature of DMR measurements enabled us to (i) probe GPCR functionality along all four G-protein signaling pathways, something presently beyond reach of most other assay platforms; (ii) dissect complex GPCR signaling patterns even in primary human cells with unprecedented accuracy; (iii) define heterotrimeric G proteins as triggers for the complex optical fingerprints; and (iv) disclose previously undetected features of GPCR behavior. Our results suggest that DMR technology will have a substantial impact on systems biology and systems pharmacology as well as for the discovery of drugs with novel mechanisms

The SIB Swiss Institute of Bioinformatics' resources: focus on curated databases

The SIB Swiss Institute of Bioinformatics (www.isb-sib.ch) provides world-class bioinformatics databases, software tools, services and training to the international life science community in academia and industry. These solutions allow life scientists to turn the exponentially growing amount of data into knowledge. Here, we provide an overview of SIB's resources and competence areas, with a strong focus on curated databases and SIB's most popular and widely used resources. In particular, SIB's Bioinformatics resource portal ExPASy features over 150 resources, including UniProtKB/Swiss-Prot, ENZYME, PROSITE, neXtProt, STRING, UniCarbKB, SugarBindDB, SwissRegulon, EPD, arrayMap, Bgee, SWISS-MODEL Repository, OMA, OrthoDB and other databases, which are briefly described in this article

Activation and Translocation of p38 Mitogen-Activated Protein Kinase After Stimulation of Monocytes With Contact Sensitizers

Recently we described the induction of tyrosine phosphorylation by contact sensitizers as an early molecular event during the activation of antigen- presenting cells. In this study, the role of the p38 mitogen-activated protein kinase for the activation of human monocytes after exposure to four structurally unrelated contact sensitizers was analyzed in comparison with the irritant benzalkonium chloride and an inductor of oxidative stress (H2O2) using immunofluorescence, Western blotting, and enzyme-linked immunosorbent assay techniques. Bio chemical analysis revealed a translocation of p38 from the cytoplasm to the detergent-resistant cell fraction only upon stimulation with contact sensitizers. The activity of p38 was studied by quantification of its phosphorylated active form with a specific antibody and by kinase assay. Although all stimulants used in this study led to the activation of p38, a translocation to the detergent-resistant fraction as well phosphorylation of the mitogen-activated protein kinase dependent transcription factor Elk-1 was induced only by contact sensitizers. Evidence for a functional relevance of mitogen-activated protein kinase activation was provided by measurement of the hapten-induced production of the proinflammatory cytokine interleukin-1β. Its release was inhibited by blocking p38-mediated signaling using the imidazole compounds SB203580 and SB202190. These data show that contact sensitizers are strong activators of the p38 mitogen-activated protein kinase. Although activation of this stress-associated pathway has been reported for many other stimuli, a unique translocation of p38 from the cytoplasm to the detergent-resistant fraction seems to be a specific event during hapten-induced activation of antigen-presenting cells