Tierexperimentelle Untersuchungen zur Behandlung der akuten Eisenvergiftung

Zusammenfassung Es wurde der Einfluß von Hexacyanoferrat(II), Desferrioxamin, Diäthylentriaminpentaessigsäure und anderer Polyaminopolycarbonsäuren auf die Letalität von Mäusen nach oraler Vergiftung mit FeSO₄ untersucht. Bei frühzeitiger oraler Applikation zeigt das Hexacyanoferrat(II) eine gesichert höhere Antidotwirksamkeit als Chelatbildner. Zu späteren Zeitpunkten erwies sich die orale Verabreichung aller Antidote als unwirksam, jedoch führt die parenterale Verabreichung von Chelatbildnern zu einer deutlichen Herabsetzung der Letalität. Stärkere Unterschiede in der Wirksamkeit von Desferrioxamin, Diäthylentriaminpentaessigsäure und der anderen untersuchten Chelatbildner liegen dabei nicht vor.     

Hemangiomas of the external auditory canal:a literature review and two new case reports

Aim  

The aim of this paper is to present two case reports of patients with hemangiomas of the external auditory canal, and to overview all cases published in English language literature so far.     

Agonist high- and low-affinity states of dopamine D2 receptors: methods of detection and clinical implications

Dopamine D₂ receptors, similar to other G-protein-coupled receptors, exist in a high- and low-affinity state for agonists. Based upon a review of the methods for detecting D₂ receptor agonist high-affinity states, we discuss alterations of such states in animal models of disease and the implications of such alterations for their labelling with positron emission tomography (PET) and single-photon emission computed tomography (SPECT) tracers. The classic approach of detecting agonist high-affinity states compares agonist competition for antagonist radioligands, in most cases using [³H]-spiperone as the radioligand; alternative approaches and radioligands have been proposed, but their claimed advantages have not been substantiated by other investigators. In view of the advantages and disadvantages of various techniques, we critically have reviewed reported findings on the detection of D₂ receptor agonist high-affinity states in a variety of animal models. These data are compared to the less numerous findings from human in vivo studies based on PET and SPECT tracers; they are interpreted in light of the finding that D₂ receptor agonist high-affinity states under control conditions may differ between rodent and human brain. The potential advantages of agonist ligands in studies of pathophysiology and as diagnostics are being discussed.     

Adaptive Designs for Dose-Finding Studies Based on Sigmoid E max Model

We propose an adaptive procedure for dose-finding in clinical trials when the primary efficacy endpoint is continuous. We model the mean of the efficacy endpoint, given the dose, as a four-parameter logistic function. The efficacy endpoint at each dose is distributed according to either a normal or a gamma distribution. We consider the cases of fixed variance and fixed coefficient of variation assuming them to be both known and unknown. The analytic formulae for the Fisher information matrix are obtained, which are used to build the locally and adaptive D -optimal designs.     

From the Cover: Quasiresonant amplification of planetary waves and recent Northern Hemisphere weather extremes

In recent years, the Northern Hemisphere has suffered several devastating regional summer weather extremes, such as the European heat wave in 2003, the Russian heat wave and the Indus river flood in Pakistan in 2010, and the heat wave in the United States in 2011. Here, we propose a common mechanism for the generation of persistent longitudinal planetary-scale high-amplitude patterns of the atmospheric circulation in the Northern Hemisphere midlatitudes. Those patterns—with zonal wave numbers m = 6, 7, or 8—are characteristic of the above extremes. We show that these patterns might result from trapping within midlatitude waveguides of free synoptic waves with zonal wave numbers k ≈ m. Usually, the quasistationary dynamical response with the above wave numbers m to climatological mean thermal and orographic forcing is weak. Such midlatitude waveguides, however, may favor a strong magnification of that response through quasiresonance.     

Microbial life at ?13 °C in the brine of an ice-sealed Antarctic lake

The permanent ice cover of Lake Vida (Antarctica) encapsulates an extreme cryogenic brine ecosystem (−13 °C; salinity, 200). This aphotic ecosystem is anoxic and consists of a slightly acidic (pH 6.2) sodium chloride-dominated brine. Expeditions in 2005 and 2010 were conducted to investigate the biogeochemistry of Lake Vida’s brine system. A phylogenetically diverse and metabolically active Bacteria dominated microbial assemblage was observed in the brine. These bacteria live under very high levels of reduced metals, ammonia, molecular hydrogen (H₂), and dissolved organic carbon, as well as high concentrations of oxidized species of nitrogen (i.e., supersaturated nitrous oxide and ∼1 mmol⋅L⁻¹ nitrate) and sulfur (as sulfate). The existence of this system, with active biota, and a suite of reduced as well as oxidized compounds, is unusual given the millennial scale of its isolation from external sources of energy. The geochemistry of the brine suggests that abiotic brine-rock reactions may occur in this system and that the rich sources of dissolved electron acceptors prevent sulfate reduction and methanogenesis from being energetically favorable. The discovery of this ecosystem and the in situ biotic and abiotic processes occurring at low temperature provides a tractable system to study habitability of isolated terrestrial cryoenvironments (e.g., permafrost cryopegs and subglacial ecosystems), and is a potential analog for habitats on other icy worlds where water-rock reactions may cooccur with saline deposits and subsurface oceans.