The effects of hypoxia on gestational diabetes mellitus in mice

Abstract. Hypoxia and oxygen sensing are mechanisms which play important roles in many physiological processes like the generation of new blood vessels, production of red blood cells, fetal development as well as in pathophysiological processes like chronic renal failure and cancer. Especially since the Nobel Prize in Physiology or Medicine 2019 was awarded to William G. Kaelin, Gregg L. Semenza and Peter J. Ratcliffe working on this specific topic a broader range of people became aware of its importance. (The Nobel Prize in Physiology or Medicine 2019 — Press release n.d.). In terms of pregnancy hypoxia is the most important determining factor when it comes to duration of gestation and the second most important in birth weight (Krampl 2002)(Jensen and Moore 1997). It is estimated that for every 1000m above sea level the average fetal birth weight decreases by 100g (Soria et al. 2013). Gestational diabetes mellitus (GDM) is defined as a state hyperglycaemia of any degree which is first recognized in pregnant women. (Menke, Casagrande, and Cowie 2018). It has a worldwide prevalence ranging from 6.1 to 30% and has lots of short- and long-term consequences like fetal overgrowth and a higher risk of getting the metabolic syndrome in later life of the child. Because of the observed opposing effects of hypoxia and GDM during pregnancy, we investigated whether hypoxia will ameliorate the GDM symptoms in pregnant mice with insulin resistance. To study the effects of hypoxia on GDM in mice, obesity was induced by feeding 4-months-old C57BL/6N dams with an obesogenic diet for 7 weeks before and throughout pregnancy. Mice fed a normal chow (NC) served as control. Animals were bred following an established protocol and were marked at day E 0.5 after mating which was considered as the beginning of pregnancy. The groups were housed either in normoxic conditions (O2 ≈ 21 %) or in normobaric hypoxia (O2 = 15 %, this corresponds to oxygen tension at 2700m altitude) during gestation; mice were sacrificed at E 9.5 (mid pregnancy) as well as in a second experiment with the same setup at E 17.5 (end pregnancy). General measurements of the dams like weight gain or embryo number were taken as well as metabolites from the lipid and glucose metabolism. On expression level was also checked for genes which play a role in hypoxia response or glucose metabolism. Central findings of the present studies were that the obesogenic diet affected the mice which could be shown through many altered parameters in mid- and in late-pregnancy like elevated serum cholesterol levels or liver triglyceride levels as well as increased insulin resistance. Concerning the effect of hypoxia on obesogenic mice a clear compensating effect of the altered parameters in the H/OD group could not be shown in mid- as well as in late-pregnancy. Due to mating problems with the mice during this study in late-pregnancy the group sizes and other parameters were not as consistent as anticipated, this makes comparison and interpretation of the present results more difficult. Part of the experiments should be repeated and further research needs to be done in order to get a better insight in the underlying mechanisms

Regulation von TRPM3 durch α2-Adrenorezeptoren in pankreatischen β-Zellen

TRPM3 ist ein Ca2+-permeabler, nichtselektiver Kationenkanal der TRP-Familie, der durch das endogene Neurosteroid Pregnenolonsulfat aktiviert werden kann. Eine funktionelle Expression des Kanals konnte unter anderem in pankreatischen β-Zellen nachgewiesen werden. Eine Aktivierung von TRPM3 in β-Zellen führt zu einem Einstrom von Ca2+ und zu einer Verstärkung der Glucose-induzierten Insulinfreisetzung. Die genaue Funktion des Kanals im Kontext der β-Zellen ist jedoch noch nicht vollständig verstanden. Die Insulinfreisetzung in β-Zellen unterliegt einer äußerst strikten und vielseitigen Regulation und wird präzise den physiologischen Begebenheiten angepasst. Viele dieser Modulationen werden hierbei über G-Protein gekoppelte Rezeptoren (GPCR) vermittelt. Da für viele TRP-Kanäle bekannt ist, dass sie durch GPCR moduliert werden und die überwiegende Mehrheit der an der Insulinfreisetzung beteiligten Ionenkanäle durch GPCR auf die eine oder andere Art moduliert werden, stellte sich die Frage, ob auch TRPM3 in β-Zellen einer solchen Regulation unterliegt. Es zeigte sich, dass die Aktivität von TRPM3 in β-Zellen und Ins1 Zellen (Insulinoma Zelllinie der Ratte) durch Noradrenalin stark und reversibel inhibiert wird. Durch pharmakologische Experimente konnte nachgewiesen werden, dass die Hemmung dabei über α2-Adrenorezeptoren vermittelt wird. Eine genauere Betrachtung des zugrundeliegenden Signalwegs offenbarte, dass die TRPM3-Hemmung durch einen Gαi/o-gekoppelten Mechanismus induziert wird. Eine Beteiligung des „klassischen“, cAMP-abhängigen Signalwegs konnte ausgeschlossen werden. In Überexpressions-experimenten zeigte sich weiterhin, dass aktivierte Gαi/o-Untereinheiten nicht an der direkten Vermittlung der Inhibition beteiligt sind. Eine Überexpression von βγ-Untereinheiten hingegen führte zu einer drastischen Verminderung der TRPM3-Aktivität. Jedoch konnten nicht alle βγ-Kombinationen die TRPM3-Hemmung induzieren. Lediglich β1 und β2, in Kombination mit einer γ-Untereinheit, waren in der Lage, die TRPM3-Aktivität zu inhibieren. Ebenso konnte in Ins1 Zellen, die mit mSIRK (einem membrangängigen Peptid, das eine Freisetzung von βγ-Untereinheiten induziert) behandelt wurden, eine Reduktion der TRPM3-Aktivität beobachtet werden. Weiterhin konnte durch Abfangen von βγ-Untereinheiten (mittels myr-Phosducin oder myr-βARKct (Polypeptide, die βγ-Untereinheiten direkt binden)) die Noradrenalin vermittelte TRPM3-Hemmung deutlich abgeschwächt werden. Eine Beteiligung der PLC, der PKC, der PLA2 und löslichen, cytosolischen Faktoren am Signalweg, der zur TRPM3-Hemmung führt, konnte hingegen weitgehend ausgeschlossen werden. Somit besteht die Möglichkeit, dass die Noradrenalin-induzierte Hemmung der TRPM3-Kanäle auf eine direkte Interaktion der βγ-Untereinheiten mit TRPM3 zurückzuführen ist. Es zeigte sich, dass nicht alle TRPM3-Spleißvarianten sensitiv für die durch α2-Adrenorezeptor vermittelte Inhibition sind bzw. nicht alle eine verminderte Aktivität nach Überexpression von βγ-Untereinheiten aufweisen. Dafür verantwortlich scheint eine 10 Aminosäure lange Sequenz zu sein, die durch Exon 17 kodiert wird und in den insensitiven Spleißvarianten (TRPM3α4 und TRPM3α5) nicht vorhanden ist. Die vorliegende Arbeit zeigt deutlich, dass TRPM3 in β-Zellen einer starken Regulierung durch α2-Adrenorezeptoren unterliegt. Dies deutet darauf hin, dass TRPM3 möglicherweise eine essentielle Funktion in β-Zellen besitzt, die einer ausgeprägten sympathischen Regulation bedarf. Die gewonnenen Erkenntnisse tragen somit zu einem besseren Verständnis der TRPM3-Kanäle im Kontext der β-Zellen bei. Die Entdeckung, dass TRPM3 durch Gαi/o-gekoppelte GPCR moduliert werden kann, stellt ebenso eine wichtige Grundlage für nachfolgende Untersuchungen bezüglich der Rolle, Funktion und Regulation von TRPM3 in anderen Geweben dar

Spanning trees of smallest maximum degree in subdivisions of graphs

\newcommand{\subdG}[1][G]{#1^\star} Given a graph $G$ and a positive integer $k$, we study the question whether $G^\star$ has a spanning tree of maximum degree at most $k$ where $G^\star$ is the graph that is obtained from $G$ by subdividing every edge once. Using matroid intersection, we obtain a polynomial algorithm for this problem and a characterization of its positive instances. We use this characterization to show that $G^\star$ has a spanning tree of bounded maximum degree if $G$ is contained in some particular graph class. We study the class of 3-connected graphs which are embeddable in a fixed surface and the class of $(p-1)$-connected $K_p$-minor-free graphs for a fixed integer $p$. We also give tightness examples for most of these classes

Exceptional sequence of severe thunderstorms and related flash floods in May and June 2016 in Germany – Part 1: Meteorological background

Abstract. During a 15-day episode from 26 May to 9 June 2016, Germany was affected by an exceptionally large number of severe thunderstorms. Heavy rainfall, related flash floods and creek flooding, hail, and tornadoes caused substantial losses running into billions of euros (EUR). This paper analyzes the key features of the severe thunderstorm episode using extreme value statistics, an aggregated precipitation severity index, and two different objective weather-type classification schemes. It is shown that the thunderstorm episode was caused by the interaction of high moisture content, low thermal stability, weak wind speed, and large-scale lifting by surface lows, persisting over almost 2 weeks due to atmospheric blocking. For the long-term assessment of the recent thunderstorm episode, we draw comparisons to a 55-year period (1960–2014) regarding clusters of convective days with variable length (2–15 days) based on precipitation severity, convection-favoring weather patterns, and compound events with low stability and weak flow. It is found that clusters with more than 8 consecutive convective days are very rare. For example, a 10-day cluster with convective weather patterns prevailing during the recent thunderstorm episode has a probability of less than 1 %

Pathfinder first light: alignment, calibration, and commissioning of the LINC-NIRVANA ground-layer adaptive optics subsystem

We present descriptions of the alignment and calibration tests of the Pathfinder, which achieved first light during our 2013 commissioning campaign at the LBT. The full LINC-NIRVANA instrument is a Fizeau interferometric imager with fringe tracking and 2-layer natural guide star multi-conjugate adaptive optics (MCAO) systems on each eye of the LBT. The MCAO correction for each side is achieved using a ground layer wavefront sensor that drives the LBT adaptive secondary mirror and a mid-high layer wavefront sensor that drives a Xinetics 349 actuator DM conjugated to an altitude of 7.1 km. When the LINC-NIRVANA MCAO system is commissioned, it will be one of only two such systems on an 8-meter telescope and the only such system in the northern hemisphere. In order to mitigate risk, we take a modular approach to commissioning by decoupling and testing the LINC-NIRVANA subsystems individually. The Pathfinder is the ground-layer wavefront sensor for the DX eye of the LBT. It uses 12 pyramid wavefront sensors to optically co-add light from natural guide stars in order to make four pupil images that sense ground layer turbulence. Pathfinder is now the first LINC-NIRVANA subsystem to be fully integrated with the telescope and commissioned on sky. Our 2013 commissioning campaign consisted of 7 runs at the LBT with the tasks of assembly, integration and communication with the LBT telescope control system, alignment to the telescope optical axis, off-sky closed loop AO calibration, and finally closed loop on-sky AO. We present the programmatics of this campaign, along with the novel designs of our alignment scheme and our off-sky calibration test, which lead to the Pathfinder's first on-sky closed loop images

The Tinnitus Research Initiative (TRI) database: A new approach for delineation of tinnitus subtypes and generation of predictors for treatment outcome

Tinnitus, the phantom perception of sound, is a frequent disorder that causes significant morbidity and treatment is elusive. A large variety of different treatment options have been proposed and from most of them some patients benefit. However, a particular treatment that helps one patient may fail for others. This suggests that there are different forms of tinnitus which differ in their pathophysiology and their response to specific treatments. Therefore, it is a major challenge for tinnitus treatment to identify the most promising therapy for a specific patient

Trauma-Associated Tinnitus: Audiological, Demographic and Clinical Characteristics

Background: Tinnitus can result from different etiologies. Frequently, patients report the development of tinnitus after traumatic injuries. However, to which extent this specific etiologic factor plays a role for the phenomenology of tinnitus is still incompletely understood. Additionally, it remains a matter of debate whether the etiology of tinnitus constitutes a relevant criterion for defining tinnitus subtypes. Objective: By investigating a worldwide sample of tinnitus patients derived from the Tinnitus Research Initiative (TRI) Database, we aimed to identify differences in demographic, clinical and audiological characteristics between tinnitus patients with and without preceding trauma. Materials: A total of 1,604 patients were investigated. Assessment included demographic data, tinnitus related clinical data, audiological data, the Tinnitus Handicap Inventory, the Tinnitus Questionnaire, the Beck Depression Inventory, various numeric tinnitus rating scales, and the World Health Organisation Quality of Life Scale (WHOQoL). Results: Our data clearly indicate differences between tinnitus patients with and without trauma at tinnitus onset. Patients suffering from trauma-associated tinnitus suffer from a higher mental burden than tinnitus patients presenting with phantom perceptions based on other or unknown etiologic factors. This is especially the case for patients with whiplash and head trauma. Patients with posttraumatic noise-related tinnitus experience more frequently hyperacousis, were younger, had longer tinnitus duration, and were more frequently of male gender. Conclusions: Trauma before tinnitus onset seems to represent a relevant criterion for subtypization of tinnitus. Patients with posttraumatic tinnitus may require specific diagnostic and therapeutic management. A more systematic and - at best - standardized assessment for hearing related sequelae of trauma is needed for a better understanding of the underlying pathophysiology and for developing more tailored treatment approaches as well.Fil: Kreuzer, Peter M.. Universitat Regensburg; AlemaniaFil: Landgrebe, Michael. Universitat Regensburg; AlemaniaFil: Schecklmann, Martin. Universitat Regensburg; AlemaniaFil: Staudinger, Susanne. Universitat Regensburg; AlemaniaFil: Langguth, Berthold. Universitat Regensburg; AlemaniaFil: Vielsmeier, Veronika. The TRI Database Study Group; AlemaniaFil: Kleinjung, Tobias. The TRI Database Study Group; AlemaniaFil: Lehner, Astrid. The TRI Database Study Group; AlemaniaFil: Poeppl, Timm B.. The TRI Database Study Group; AlemaniaFil: Figueiredo, Ricardo. The TRI Database Study Group; AlemaniaFil: Azevedo, Andréia. The TRI Database Study Group; AlemaniaFil: Binetti, Ana Carolina. The TRI Database Study Group; AlemaniaFil: Elgoyhen, Ana Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; Argentina. The TRI Database Study Group; AlemaniaFil: Rates, Marcelo. The TRI Database Study Group; AlemaniaFil: Coelho, Claudia. The TRI Database Study Group; AlemaniaFil: Vanneste, Sven. The TRI Database Study Group; AlemaniaFil: de Ridder, Dirk. The TRI Database Study Group; AlemaniaFil: van de Heyning, Paul. The TRI Database Study Group; AlemaniaFil: Zeman, Florian. The TRI Database Study Group; AlemaniaFil: Mohr, Markus. The TRI Database Study Group; AlemaniaFil: Koller, Michael. The TRI Database Study Group; Alemani

Talbot-Lau x-ray phase-contrast setup for fast scanning of large samples

Abstract Compared to conventional attenuation x-ray radiographic imaging, the x-ray Talbot-Lau technique provides further information about the scattering and the refractive properties of the object in the beam path. Hence, this additional information should improve the diagnostic process concerning medical applications and non-destructive testing. Nevertheless, until now, due to grating fabrication process, Talbot-Lau imaging suffers from small grating sizes (70 mm diameter). This leads to long acquisition times for imaging large objects. Stitching the gratings is one solution. Another one consists of scanning Talbot-Lau setups. In this publication, we present a compact and very fast scanning setup which enables imaging of large samples. With this setup a maximal scanning velocity of 71.7 mm/s is possible. A resolution of 4.1 lines/mm can be achieved. No complex alignment procedures are necessary while the field of view comprises 17.5 × 150 cm2. An improved reconstruction algorithm concerning the scanning approach, which increases robustness with respect to mechanical instabilities, has been developed and is presented. The resolution of the setup in dependence of the scanning velocity is evaluated. The setup imaging qualities are demonstrated using a human knee ex-vivo as an example for a high absorbing human sample

Synthesis and SAR evaluation of coumarin derivatives as potent cannabinoid receptor agonists

We report the development and extensive structure-activity relationship evaluation of a series of modified coumarins as cannabinoid receptor ligands. In radioligand, and [S-35]GTP gamma S binding assays the CB receptor binding affinities and efficacies of the new ligands were determined. Furthermore, we used a ligand-based docking approach to validate the empirical observed results. In conclusion, several crucial structural requirements were identified. The most potent coumarins like 3-butyl-7-(1-butylcyclopentyl)-5-hydroxy-2H-chromen-2-one (36b, K-i CB2 13.7 nM, EC50 18 nM), 7-(1-butylcyclohexyl)-5-hydroxy-3-propyl-2H-chromen-2-one (39b, K-i CB2 6.5 nM, EC50 4.51 nM) showed a CB2 selective agonistic profile with low nanomolar affinities. (C) 2021 Published by Elsevier Masson SAS.Peer reviewe