39 research outputs found
Catecholamines and phosphate excretion by the remnant kidney
Catecholamines and phosphate excretion by the remnant kidney. The remnant kidney (RK) exhibits an enhanced fractional excretion of phosphate (FEPi) even in the absence of parathyroid hormone (PTH). Thus, factors other than PTH contribute to this adaptive phosphaturia. Dopamine (DA) infusion is phosphaturic, whereas stimulation of adrenoreceptors is antiphosphaturic. Therefore, the hypothesis that alterations in catecholamines by the RK may be associated with the phosphaturia exhibited by this model was tested. Male Sprague-Dawley rats were subjected to right nephrectomy and surgical ablation of the left renal poles. Four weeks later rats with a RK (N = 10) and control rats with intact kidneys (N = 9) were anesthetized and thyroparathy-roidectomized (TPTX). Two hours after TPTX, urine samples were collected for measurements of urinary free DA excretion. Subsequently, 3% inulin in saline was infused for one hour and a 30 minute clearance was taken. The kidneys were then removed and frozen for determination of tissue norepinephrine (NE) and DA concentrations. Glomerular filtration rate was significantly lower in rats with a RK than in controls (0.57 ± 0.07 vs. 0.83 ± 0.08 ml/min/g kidney wt), whereas fractional excretion of phosphate (FEPi) was significantly higher (29.4 ± 4.7 vs. 8.3 ± 3.4%). Tissue NE concentration was significantly lower in the RK than in the control intact kidney (85.10 ± 4.95 vs. 129.60 ± 7.20 ng/g), whereas urinary DA excretion per nephron was significantly higher in the RK (0.12 ± 0.02 vs. 0.04 ± 0.006 pg/min). Infusion of the specific DA-1 receptor antagonist (SCH 23390) in rats with a RK significantly decreased the FEPi when compared to the saline infused control group (Δ-5.2 ± 4.3 vs. +9.5 ± 5.2%), however, urinary c-AMP excretions were not different. We conclude that decreased renal sympathetic nerve tone, unchanged tissue DA levels, and an increased DA synthesis per residual nephron are associated with the enhanced FEPi exhibited by the RK
From gradual spreading to catastrophic collapse - Reconstruction of the 1888 Ritter Island volcanic sector collapse from high-resolution 3D seismic data
Volcanic island flank collapses have the potential to trigger devastating tsunamis threatening coastal communities and infrastructure. The 1888 sector collapse of Ritter Island, Papua New Guinea (in the following called Ritter) is the most voluminous volcanic island flank collapse in historic times. The associated tsunami had run-up heights of more than 20 m on the neighboring islands and reached settlements 600 km away from its source. This event provides an opportunity to advance our understanding of volcanic landslide-tsunami hazards. Here, we present a detailed reconstruction of the 1888 Ritter sector collapse based on high-resolution 2D and 3D seismic and bathymetric data covering the failed volcanic edifice and the associated mass-movement deposits. The 3D seismic data reveal that the catastrophic collapse of Ritter
occurred in two phases: (1) Ritter was first affected by deep-seated, gradual spreading over a long time period, which is manifest in pronounced compressional deformation within the volcanic edifice and the adjacent seafloor sediments. A scoria cone at the foot of Ritter acted as a buttress, influencing the displacement and deformation of the western flank of the volcano and causing shearing within the volcanic edifice. (2) During the final, catastrophic phase of the collapse, about 2.4 kmÂł of Ritter disintegrated almost entirely and travelled as a highly energetic mass flow, which incised the underlying sediment. The irregular topography west of Ritter is a product of both compressional deformation and erosion. A crater-like depression underlying the recent volcanic cone and eyewitness accounts suggest that an explosion may have accompanied the catastrophic collapse. Our findings demonstrate that volcanic sector collapses may transform from slow gravitational deformation to catastrophic collapse. Understanding the processes involved in such a transformation is crucial for assessing the hazard potential of other volcanoes with slowly deforming flanks such as Mt. Etna or Kilauea
RV SONNE 252 Cruise Report / Fahrtbericht, Yokohama : 05.11.2016 - Nouméa : 18.12.2016. SO252 : RITTER ISLAND Tsunami potential of volcanic flank collapses
Large volcanic debris flows associated with volcanic island flank collapses may cause devastating tsunamis as they enter the ocean. Computer simulations show that the largest of these volcanic debris flows on oceanic islands such as Hawaii or the Canaries can cause ocean-wide tsunamis (Løvholt et al., 2008; Waythomas et al., 2009). However, the magnitude of these tsunamis is subject to on-going debate as it depends particularly on landslide transport and emplacement processes (Harbitz et al. 2013). A robust understanding of these factors is thus essential in order to assess the hazard of volcanic flank collapses. Recent studies have shown that emplacement processes are far more complex than assumed previously. With a collapsed volume of about 5 km3 the 1888 Ritter Island flank collapse is the largest in historic times and represents an ideal natural laboratory for several reasons: (I) The collapse is comparatively young and the marine deposits are clearly visible, (II) the pre-collapse shape of the island is historically documented and (III) eyewitness reports documenting tsunami arrival times, run-up heights and inundation levels on neighboring islands are available. We propose to collect bathymetric, high resolution 2D and 3D seismic data as well as seafloor samples from the submarine deposits off Ritter Island to learn about the mobility and emplacement dynamics of the 1888 flank collapse landslide. A comparison to similar studies from other volcanic islands will provide an improved understanding of emplacement processes of volcanic island landslides and their overall tsunamigenic potential. In addition, a detailed knowledge of the 1888 landslide processes in combination with tsunami constraints from eyewitness reports provides a unique possibility to determine the landslide velocity, which can then be used in subsequent hazard analyses for ocean islands.peer-reviewe
In Vitro Evolution of Allergy Vaccine Candidates, with Maintained Structure, but Reduced B Cell and T Cell Activation Capacity
Allergy and asthma to cat (Felis domesticus) affects about 10% of the population in affluent countries. Immediate allergic symptoms are primarily mediated via IgE antibodies binding to B cell epitopes, whereas late phase inflammatory reactions are mediated via activated T cell recognition of allergen-specific T cell epitopes. Allergen-specific immunotherapy relieves symptoms and is the only treatment inducing a long-lasting protection by induction of protective immune responses. The aim of this study was to produce an allergy vaccine designed with the combined features of attenuated T cell activation, reduced anaphylactic properties, retained molecular integrity and induction of efficient IgE blocking IgG antibodies for safer and efficacious treatment of patients with allergy and asthma to cat. The template gene coding for rFel d 1 was used to introduce random mutations, which was subsequently expressed in large phage libraries. Despite accumulated mutations by up to 7 rounds of iterative error-prone PCR and biopanning, surface topology and structure was essentially maintained using IgE-antibodies from cat allergic patients for phage enrichment. Four candidates were isolated, displaying similar or lower IgE binding, reduced anaphylactic activity as measured by their capacity to induce basophil degranulation and, importantly, a significantly lower T cell reactivity in lymphoproliferative assays compared to the original rFel d 1. In addition, all mutants showed ability to induce blocking antibodies in immunized mice.The approach presented here provides a straightforward procedure to generate a novel type of allergy vaccines for safer and efficacious treatment of allergic patients
Attenuation of chemokine receptor function and surface expression as an immunomodulatory strategy employed by human cytomegalovirus is linked to vGPCR US28
Am Rande der Lebensfähigkeit : Der Einfluss einer Frühgeburt vor der 28. Schwangerschaftswoche auf Eltern und ihre Paarbeziehung
In dieser Masterarbeit wurde das Thema, am Rande der Lebensfähigkeit: Einflüsse einer extremen Frühgeburt auf die Eltern und Partnerschaft, erforscht. Die Erhebung fand anhand einer qualitativen Forschung in Form eines Fragebogens statt. Es fand eine Erhebung mit rekonstruierenden Fragen statt zu verschiedenen Zeiten kurz nach der Geburt und ein Jahr nach der Geburt und heute. Verglichen wurden in der Erhebung zwei Gruppen: Eltern mit einer extremen Frühgeburtserfahrung und Eltern mit einer Normalgeburtserfahrung.
Ergebnisse dieser Arbeit zeigen, einen höheren negativen Einfluss einer Frühgeburtserfahrung auf die Paarzufriedenheit und Partnerschaftsqualität ein Jahr nach der Geburt auf. In der Gruppe der Frühgeburten wurde ebenfalls ein höherer Wert an Depression von 52% der Befragten vernommen. Diese zeigte besonders einen Zusammenhang mit einer niedrigeren Partner-schaftsqualität und Paarzufriedenheit. Ebenfalls konnte ein hohes Maß an Veränderungen in der Emotionalität der Partnerschaft und Kommunikation und Konfliktverhalten festgestellt werden. Die Partnerschaft wurde besonders durch die Bindungsunterstützung und medizinische Begleitung bereits im Krankenhaus positiv beeinflusst. Fast alle Paare wünschen sich mehr Angebote für Mutter, Vater und die eigene PartnerschaftIn this master’s thesis, the topic, on the edge of viability: the impact of preterm birth before 28 weeks of pregnancy on parents and their romantic relationship, was explored. The research was conducted by means of quantitative methods in the form of a questionnaire. The questionnaire contained reconstructive questions to their mental health and romantic relationship at three different times: after birth, one year after birth and today. Two groups were compared in the survey: Parents with an extreme preterm birth experience and parents with a normal birth experience. The results of this work show a negative influence of preterm birth on relationship satisfaction and partnership quality one year after birth. Parents of an extreme premature infant are more likely to suffer from depression (40%). The results show a high correlation of depression and a lower partnership quality and relationship satisfaction. Furthermore, a higher amount of emotional changes, lower communication skills and an increase of conflicts in the parental relations of parents with an extreme premature infant were found. The romantic relationship was positively influenced by the support in the hospital in establishing a positive attachment and a closer involvement of medical tasks. Almost all couples desire more help for mother, father and their own relationship
Attractiveness of variety : the use of diversity management in external communication using the example of Beiersdorf AG
Die vorliegende Bachelorarbeit gibt einen Überblick über dem Einsatz von Diversity Management in der externen Kommunikation am Beispiel der Beiersdorf AG. Relevante theoretische Ansätze zur Unternehmenskommunikation, dessen Funktionen und Ziele für den Unternehmenserfolg werden erklärt und erläutert. Des Weiteren Fokussiert sich die Arbeit, auf das Diversity Management und dessen Einsatzes in der externen Unternehmenskommunikation. Um herauszustellen wie das Diversity Management als Instrument der externen Unternehmenskommunikation eingesetzte werden kann, werden in der Untersuchung verschiedene Maßnahmen erläutert, als Beispiel wird das Unternehmen der Beiersdorf AG genutzt. Durch eine empirische Untersuchung wird eine Erkenntnis darüber erhalten, welche Relevanz Diversity Management auf Grundlage der externen Unternehmenskommunikation hat