119 research outputs found
Silicon nanowire based sensor for highly sensitive and selective detection of ammonia
The precise determination of the type and concentration of gases is of increasing importance in numerous applications. Despite the diverse operating principles of todayÂŽs gas sensors, technological trends can be summarized with the keyword miniaturization, because of the resulting benefits such as integrability and energy efficiency.
This work deals with the development and fabrication of novel nanowire based gas sensors, which in comparison to conventional devices have an advantageous combination of high sensitivity and selectivity with low power consumption and small size. On the basis of grown silicon nanowires, sensors based on the functional principle of classical Schottky barrier field effect transistors with abrupt metal-semiconductor contacts are fabricated. The sensing performance of the devices is investigated with respect to the detection of ammonia. Ammonia concentrations down to 170 ppb are measured with a sensor response of more than 160 % and a theoretical limit of detection of 20 ppb is determined.
Selectivity investigations show that no cross sensitivity to most common solvents occurring in living spaces exists. Moisture influences on the device are studied and reveal that the sensor responds within seconds, making it potentially suitable as humidity sensor. Moreover, it is shown that a higher relative humidity and higher temperatures decrease the sensor sensitivity. In terms of possible applications, it is a great advantage that the maximum sensitivity is achieved at 25 °C.
With respect to sensitivity and selectivity an enhancement is demonstrated compared to most nanosensors known from the literature. Hence, the technology offers the potential to complement conventional measurement systems in future sensor technology especially in portable applications.Die prÀzise Bestimmung der Art und Konzentration von Gasen erlangt in zahlreichen Anwendungsgebieten zunehmend an Bedeutung. Trotz der vielfÀltigen Wirkprinzipien heutiger Gassensoren lassen sich die technologischen Trends mit dem Schlagwort Miniaturisierung zusammenfassen, da sich daraus entscheidende Vorteile wie Integrierbarkeit und Energieeffizienz ergeben.
Diese Arbeit beschĂ€ftigt sich mit der Entwicklung und Herstellung neuartiger nanodrahtbasierter Gassensoren, welche im Vergleich zu klassischen Sensoren eine vorteilhafte Kombination von hoher SensitivitĂ€t und SelektivitĂ€t bei geringem Stromverbrauch und geringer GröĂe aufweisen. Auf der Grundlage gewachsener Silizium-NanodrĂ€hte werden Sensoren mit abrupten Metall-Halbleiter-Kontakten hergestellt, welche auf dem Funktionsprinzip klassischer Schottkybarrieren-Feldeffekttransistoren beruhen. Die Eignung der Sensoren wird in Bezug auf die Detektion von Ammoniak untersucht. Dabei kann eine minimale Ammoniakkonzentration von 170 ppb mit einer SignalĂ€nderung von mehr als 160 % gemessen werden, wobei die theoretische Nachweisgrenze mit 20 ppb ermittelt wird.
SelektivitĂ€tsuntersuchungen zeigen, dass keine Querempfindlichkeit gegenĂŒber den am hĂ€ufigsten in WohnrĂ€umen vorkommenden Lösungsmitteln besteht. FeuchtigkeitseinflĂŒsse auf den Sensor werden untersucht und es wird nachgewiesen, dass der Sensor Ansprechzeiten im Sekundenbereich besitzt, was ihn zu einem potenziell geeigneten Feuchtigkeitssensor macht. DarĂŒber hinaus wird gezeigt, dass eine höhere relative Luftfeuchtigkeit und höhere Umgebungstemperaturen die SensorsensitivitĂ€t verringern. In Bezug auf mögliche Einsatzgebiete stellt die maximale Empfindlichkeit bei 25 °C einen groĂen Vorteil da.
Bezogen auf SensitivitĂ€t und SelektivitĂ€t wird somit eine Verbesserung im Vergleich zu den meisten aus der Literatur bekannten Nanosensoren demonstriert. Damit bietet die Technologie das Potential, konventionelle Messsysteme in zukĂŒnftiger Sensorik vor allem in portablen Anwendungen zu ergĂ€nzen
A genome-wide survey for prion-regulated miRNAs associated with cholesterol homeostasis
Bovine spongiform encephalopathy infection alters endogenous retrovirus expression in distinct brain regions of cynomolgus macaques (Macaca fascicularis)
<p>Abstract</p> <p>Background</p> <p>Prion diseases such as bovine spongiform encephalopathies (BSE) are transmissible neurodegenerative diseases which are presumably caused by an infectious conformational isoform of the cellular prion protein. Previous work has provided evidence that in murine prion disease the endogenous retrovirus (ERV) expression is altered in the brain. To determine if prion-induced changes in ERV expression are a general phenomenon we used a non-human primate model for prion disease.</p> <p>Results</p> <p>Cynomolgus macaques (<it>Macaca fasicularis</it>) were infected intracerebrally with BSE-positive brain stem material from cattle and allowed to develop prion disease. Brain tissue from the <it>basis pontis </it>and <it>vermis cerebelli </it>of the six animals and the same regions from four healthy controls were subjected to ERV expression profiling using a retrovirus-specific microarray and quantitative real-time PCR. We could show that Class I gammaretroviruses HERV-E4-1, ERV-9, and MacERV-4 increase expression in BSE-infected macaques. In a second approach, we analysed ERV-K-(HML-2) RNA and protein expression in extracts from the same cynomolgus macaques. Here we found a significant downregulation of both, the macaque ERV-K-(HML-2) Gag protein and RNA in the frontal/parietal cortex of BSE-infected macaques.</p> <p>Conclusions</p> <p>We provide evidence that dysregulation of ERVs in response to BSE-infection can be detected on both, the RNA and the protein level. To our knowledge, this is the first report on the differential expression of ERV-derived structural proteins in prion disorders. Our findings suggest that endogenous retroviruses may induce or exacerbate the pathological consequences of prion-associated neurodegeneration.</p
Extensional faulting on Tinos island, Aegean sea, Greece: How many detachments?
Zircon and apatite fission track (ZFT and AFT) and (U-Th)/He, 40Ar/39Ar hornblende, and U-Pb zircon ages from the granites of Tinos Island in the Aegean Sea, Greece, suggest, together with published ZFT data, that there are three extensional detachments on Tinos. The Tinos granites crosscut the Tinos detachment. Cooling of the granites was controlled by the Livadi detachment, which occurs structurally above the Tinos detachment. Our U-Pb zircon age is 14.6 ± 0.2 Ma and two 40Ar/39Ar hornblende ages are 14.4 ± 0.4 and 13.7 ± 0.4 Ma. ZFT and AFT ages go from 14.4 ± 1.2 to 12.2 ± 1.0 Ma and 12.8 ± 2.4 to 11.9 ± 2.0 Ma. (U-Th)/He ages are from 10.4 ± 0.2 to 9.9 ± 0.2 Ma (zircon) and 11.9 ± 0.5 to 10.0 ± 0.3 Ma (apatite). All ages decrease northeastward in the direction of hanging wall transport on the Livadi detachment and age-distance relationships yield a slip rate of 2.6 (+3.3 / â1.0) km Maâ1. This rate is smaller than a published slip rate of 6.5 km Maâ1 for the Vari detachment, which is another detachment structurally above the Tinos detachment. Because of the different rates and because published ZFT ages from the footwall of the Vari detachment are âŒ10 Ma, we propose that the Vari detachment has to be distinguished from the older Livadi detachment. We discuss various models of how the extensional detachments may have evolved and prefer a scenario in which the Vari detachment cut down into the footwall of the Livadi detachment successively exhuming deeper structural units. The thermochronologic ages demonstrate the importance of quantitative data for constraining localization processes during extensional deformation
Water in cratonic lithosphere : calibrating laboratory-determined models of electrical conductivity of mantle minerals using geophysical and petrological observations
Author Posting. © American Geophysical Union, 2012. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Geochemistry Geophysics Geosystems 13 (2012): Q06010, doi:10.1029/2012GC004055.Measurements of electrical conductivity of âslightly dampâ mantle minerals from different laboratories are inconsistent, requiring geophysicists to make choices between them when interpreting their electrical observations. These choices lead to dramatically different conclusions about the amount of water in the mantle, resulting in conflicting conclusions regarding rheological conditions; this impacts on our understanding of mantle convection, among other processes. To attempt to reconcile these differences, we test the laboratory-derived proton conduction models by choosing the simplest petrological scenario possible â cratonic lithosphere â from two locations in southern Africa where we have the most complete knowledge. We compare and contrast the models with field observations of electrical conductivity and of the amount of water in olivine and show that none of the models for proton conduction in olivine proposed by three laboratories are consistent with the field observations. We derive statistically model parameters of the general proton conduction equation that satisfy the observations. The pre-exponent dry proton conduction term (Ï0) and the activation enthalpy (ÎHwet) are derived with tight bounds, and are both within the broader 2Ï errors of the different laboratory measurements. The two other terms used by the experimentalists, one to describe proton hopping (exponent r on pre-exponent water content Cw) and the other to describe H2O concentration-dependent activation enthalpy (term αCw1/3 added to the activation energy), are less well defined and further field geophysical and petrological observations are required, especially in regions of higher temperature and higher water content.The SAMTEX data were acquired through funding
provided by the Continental Dynamics program of the U.S.
National Science Foundation (grant EAR0455242 to RLE),
the South African Department of Science and Technology
(grant to South African Council for Geoscience), and Science
Foundation Ireland (grant 05/RGP/GEO001 to AGJ) plus financial
and/or logistical support provided by all members of
the SAMTEX consortium. JF was initially supported by an IRCSET grant to AGJ for
the TopoMed project (TopoMed: Plate reorganization in the
western Mediterranean: Lithospheric causes and topographic
consequences) within the European Science Foundationâs TOPOEUROPE
EUROCORES (http://www.esf.org/activities/eurocores/
running-programmes/topo-europe.html), and subsequently by
an SFI PI grant (10/IN.1/I3022) to AGJ for IRETHERM
(www.iretherm.ie).2012-12-1
Textures of eclogites and blueschists from Syros island, Greece: inferences for elastic anisotropy of subducted oceanic crust
Many blueschists and eclogites are inferred to have formed from oceanic basalts in subducted slabs. Knowledge of their elastic behaviour is essential for reconstructing the internal structure of subduction zones. The Cycladic Blueschist Unit, exposed on Syros Island (Greece), contains rocks belonging to an exhumed Tertiary subduction complex. They were possibly part of a subduction channel, a shear zone above the subducting slab in which exhumation is possible during subduction. Intense plastic deformation, forming crystallographic preferred orientations (CPO), accompanied blueschist and eclogite metamorphism. CPO of the constituent minerals in the collected samples was determined by time-of-flight neutron diffraction. Two samples are foliated fine-grained blueschists with strong CPO, rich in glaucophane, zoisite and phengite. Two coarser-grained eclogite samples rich in omphacite and clinozoisite, or glaucophane, have weaker CPO. Vp and Vs anisotropies were computed from the orientation distribution function and single-crystal elastic constants. All samples show velocity maxima parallel to the mineral lineation, and minima normal to the foliation, providing important constraints on orientations of seismic anisotropy in subduction channels. Vp anisotropies are up to three times higher (6.5-12%) in the blueschists than in the eclogites (3-4%), pointing to a potentially important lithological control of elastic anisotropy in subducted oceanic crust
Silicon nanowire based sensor for highly sensitive and selective detection of ammonia
The precise determination of the type and concentration of gases is of increasing importance in numerous applications. Despite the diverse operating principles of todayÂŽs gas sensors, technological trends can be summarized with the keyword miniaturization, because of the resulting benefits such as integrability and energy efficiency.
This work deals with the development and fabrication of novel nanowire based gas sensors, which in comparison to conventional devices have an advantageous combination of high sensitivity and selectivity with low power consumption and small size. On the basis of grown silicon nanowires, sensors based on the functional principle of classical Schottky barrier field effect transistors with abrupt metal-semiconductor contacts are fabricated. The sensing performance of the devices is investigated with respect to the detection of ammonia. Ammonia concentrations down to 170 ppb are measured with a sensor response of more than 160 % and a theoretical limit of detection of 20 ppb is determined.
Selectivity investigations show that no cross sensitivity to most common solvents occurring in living spaces exists. Moisture influences on the device are studied and reveal that the sensor responds within seconds, making it potentially suitable as humidity sensor. Moreover, it is shown that a higher relative humidity and higher temperatures decrease the sensor sensitivity. In terms of possible applications, it is a great advantage that the maximum sensitivity is achieved at 25 °C.
With respect to sensitivity and selectivity an enhancement is demonstrated compared to most nanosensors known from the literature. Hence, the technology offers the potential to complement conventional measurement systems in future sensor technology especially in portable applications.Die prÀzise Bestimmung der Art und Konzentration von Gasen erlangt in zahlreichen Anwendungsgebieten zunehmend an Bedeutung. Trotz der vielfÀltigen Wirkprinzipien heutiger Gassensoren lassen sich die technologischen Trends mit dem Schlagwort Miniaturisierung zusammenfassen, da sich daraus entscheidende Vorteile wie Integrierbarkeit und Energieeffizienz ergeben.
Diese Arbeit beschĂ€ftigt sich mit der Entwicklung und Herstellung neuartiger nanodrahtbasierter Gassensoren, welche im Vergleich zu klassischen Sensoren eine vorteilhafte Kombination von hoher SensitivitĂ€t und SelektivitĂ€t bei geringem Stromverbrauch und geringer GröĂe aufweisen. Auf der Grundlage gewachsener Silizium-NanodrĂ€hte werden Sensoren mit abrupten Metall-Halbleiter-Kontakten hergestellt, welche auf dem Funktionsprinzip klassischer Schottkybarrieren-Feldeffekttransistoren beruhen. Die Eignung der Sensoren wird in Bezug auf die Detektion von Ammoniak untersucht. Dabei kann eine minimale Ammoniakkonzentration von 170 ppb mit einer SignalĂ€nderung von mehr als 160 % gemessen werden, wobei die theoretische Nachweisgrenze mit 20 ppb ermittelt wird.
SelektivitĂ€tsuntersuchungen zeigen, dass keine Querempfindlichkeit gegenĂŒber den am hĂ€ufigsten in WohnrĂ€umen vorkommenden Lösungsmitteln besteht. FeuchtigkeitseinflĂŒsse auf den Sensor werden untersucht und es wird nachgewiesen, dass der Sensor Ansprechzeiten im Sekundenbereich besitzt, was ihn zu einem potenziell geeigneten Feuchtigkeitssensor macht. DarĂŒber hinaus wird gezeigt, dass eine höhere relative Luftfeuchtigkeit und höhere Umgebungstemperaturen die SensorsensitivitĂ€t verringern. In Bezug auf mögliche Einsatzgebiete stellt die maximale Empfindlichkeit bei 25 °C einen groĂen Vorteil da.
Bezogen auf SensitivitĂ€t und SelektivitĂ€t wird somit eine Verbesserung im Vergleich zu den meisten aus der Literatur bekannten Nanosensoren demonstriert. Damit bietet die Technologie das Potential, konventionelle Messsysteme in zukĂŒnftiger Sensorik vor allem in portablen Anwendungen zu ergĂ€nzen
Die Charakterisierung von âtransient receptor potential vanilloidâ 4 (TRPV4)-KanĂ€len in humanen Hornhautkeratozyten
The transient receptor potential vanilloid 4 (TRPV4) ion channel is a nonselective cation channel and osmosensor, which is permeable to calcium in response to various stimuli like moderate heat, hypotonicity, shear stress and pharmacological agonists like GSK1016790A. The functional expression of TRPV4 has already been validated in two out of three cellular layers of the cornea of the human eye, namely the corneal epithelium and endothelium. However, TRPV4 has not yet been investigated in the dominating cells of the corneal stroma, including the human corneal keratocytes (HCK). These cells contribute to the functionality of the cornea and play an important role in corneal wound healing. This Ca2+-dependent process has to take place in an orderly manner, which is not least important for haze-free regeneration after ophthalmological surgical procedures or after keratitis. TRPV4 may have a great influence on Ca2+ regulation in HCK, and it therefore may also be involved in the complex process of stromal wound healing. Therefore, the aim of this thesis was to characterize the functional expression of TRPV4 channels in HCK using different activation mechanisms.
For this purpose, a SV40-induced immortalized permanent cell line of HCK was used as an in vitro cell model for stromal keratocytes. Fluorescence calcium imaging was used to measure intracellular calcium during the experiments. In addition, the classical and planar patch-clamp techniques were used to measure whole-cell currents.
Extracellular application of the specific TRPV4 agonist GSK1016790A (5 ÎŒmol/l) led to an increase of the fluorescence ratio f340/f380, which is proportional to the intracellular calcium concentration ([Ca2+]i). In addition, in- and outward whole-cell currents were also increased in the presence of GSK1016790A (10 ÎŒmol/l). Furthermore, two other TRPV4 activation mechanisms, namely hypotonic challenge as well as moderate heat (28°C â 34°C), led to similar effects in comparison with the pharmacological approach. The specific TRPV4 antagonist GSK2193874 (10 ÎŒmol/l) was able to suppress the GSK1016790A and hypotonicity induced calcium increase in HCK. Moreover, classical patch-clamp recordings revealed a chloride conductivity of HCK, since the negative reversal potential became more positive when sodium chloride was replaced by sodium gluconate in the extracellular measuring solution.
In conclusion, the results of this study demonstrate the functional expression of TRPV4 in HCK for the first time.Der Transient Receptor Potential Vanilloid 4 (TRPV4) Ionenkanal ist ein nichtselektiver Kationenkanal und Osmosensor, der als Reaktion auf verschiedene Stimuli wie moderate Hitze, Hypotonie, Scherstress und pharmakologischen Agonisten wie GSK1016790A fĂŒr Kalzium permeabel ist. Die funktionelle Expression von TRPV4 konnte bereits in zwei von drei Zellschichten der Hornhaut des menschlichen Auges nachgewiesen werden, und zwar im Hornhautepithel und -endothel, jedoch noch nicht in den dominierenden Zellen des Hornhautstromas einschlieĂlich der humanen Hornhautkeratozyten (HCK). Diese tragen zur FunktionalitĂ€t der Hornhaut bei und spielen in der kornealen Wundheilung eine wichtige Rolle. Dass dieser calciumabhĂ€ngige Prozess in geordneter Art und Weise ablĂ€uft, ist nicht zuletzt wichtig fĂŒr eine trĂŒbungsfreie Regeneration nach ophthalmologischen operativen Eingriffen oder nach Keratitiden. Die TRPV4-KanĂ€le haben vermutlich einen groĂen Einfluss auf die Calciumregulierung in HCK und sind daher möglicherweise auch im komplexen Prozess der stromalen Wundheilung involviert. Das Ziel dieser Arbeit war daher die funktionelle Expression von TRPV4-KanĂ€len ĂŒber verschiedene Aktivierungsmechanismen in HCK nĂ€her zu charakterisieren.
Zu diesem Zweck wurde eine SV40-induziert immortalisierte permanente HCK-Zelllinie als in vitro Zellmodell fĂŒr stromale Keratozyten verwendet. Ăber das Fluoreszenz-Kalzium-Imaging wurde die intrazellulĂ€re Kalziumkonzentration wĂ€hrend der Versuche gemessen. ZusĂ€tzlich wurde die klassische und die planare Patch-Clamp Technik zur Messung von Ganzzellströmen verwendet.
Die extrazellulĂ€re Zugabe des spezifischen TRPV4-Agonisten GSK1016790A (5 ÎŒmol/l) fĂŒhrte zu einem Anstieg des FluoreszenzverhĂ€ltnisses f340/f380, welches proportional zur intrazellulĂ€ren Kalziumkonzentration ([Ca2+]i) ist. Die ein- und auswĂ€rtsgerichteten Ganzzellströme erhöhten sich ebenfalls in Gegenwart von GSK1016790A (10 ÎŒmol/l). Zwei weitere TRPV4 Aktivierungsmechanismen, wie hypotoner Stress und moderate Hitze (28°C â 34°C) fĂŒhrten zu Ă€hnlichen Effekten wie im pharmakologischen Ansatz. Der spezifische TRPV4-Antagonist GSK2193874 (10 ÎŒmol/l) war in der Lage, den durch GSK1016790A und Hypotonie induzierten Calciumanstieg in HCK zu unterdrĂŒcken. DarĂŒber hinaus zeigten klassische Patch-Clamp Messungen eine ChloridleitfĂ€higkeit von HCK, da das negative Umkehrpotential nach Ersetzen von Natriumchlorid durch Natriumgluconat in der extrazellulĂ€ren Messlösung positiver wurde.
Zusammenfassend lÀsst sich sagen, dass die Ergebnisse dieser Studie erstmals eine funktionelle Expression von TRPV4 in HCK demonstrieren
Zirkulierende Angiopoietin-2- und Tie-2-Konzentrationen in Assoziation zur Nierenfunktion in einer populationsbasierten Studie
Ein intaktes Angiopoietin/Tie-2-Liganden-Rezeptor-System ist unabdingbar fĂŒr die endotheliale Regulierung und damit fĂŒr das Ăberleben eines Organismus. Erhöhte Konzentrationen von zirkulierendem Ang-2 sind eng assoziiert mit Nierenerkrankungen und damit mit einem progredienten Verlust der glomerulĂ€ren Filtrationsleistung. Die vorliegende Arbeit beschreibt die Assoziationen zwischen zirkulierenden Ang-2- und Tie-2-Konzentrationen mit funktionellen Nierenfunktionsparametern in einer populationsbasierten Studie mit insgesamt 7169 Probanden aus zwei unabhĂ€ngig voneinander erhobenen Kohorten (SHIP-1 und SHIP-Trend). Die Nierenfunktion wurde mittels Kreatinin, Cystatin C, eGFR(Krea) oder eGFR(Cys) und des uACRs untersucht. Zur statistischen Analyse wurden Varianz- und lineare Regressionsanalysen durchgefĂŒhrt. In der Gesamtpopulation stellte sich eine starke positive Assoziation zwischen Ang-2 und Cystatin C oder uACR, sowie eine inverse Assoziation zwischen Ang-2 und eGFR(Cys) dar. Diese Ergebnisse blieben auch in der Subpopulation mit Probanden ohne arterielle Hypertonie und Diabetes mellitus Typ 2 erhalten. Die Beziehungen zwischen Ang-2 und Kreatinin sowie eGFR(Krea) waren U-förmig und interessanterweise insgesamt weniger stark im Vergleich zu Cystatin C bzw. eGFR(Cys). FĂŒr Tie-2 konnten signifikante Assoziationen vor allem fĂŒr Cystatin C und eGFR(Cys) verzeichnet werden. ErgĂ€nzend zum bisherigen Wissensstand konnte in der Studie ein Zusammenhang zu Ang-2 bei bereits geringfĂŒgig reduzierter eGFR beschrieben werden. Zusammenfassend bestĂ€tigten die statistischen Analysen, dass Ang-2 eng im Zusammenhang mit sensitiven und prognostischen Parametern fĂŒr eine NierenschĂ€digung steht. Trotz Bildung einer Subpopulation mit Probanden ohne arterielle Hypertonie und Diabetes mellitus Typ 2, zwei Erkrankungen, die mit erhöhten Ang-2-, Tie-2- und Cystatin C-Konzentrationen assoziiert sind, blieben die Beziehungen fĂŒr Cystatin C, eGFR(Cys) und uACR in der Subpopulation bestehen. Die Unterschiede zu den Ergebnissen der Analysen mit Kreatinin und eGFR(Krea) wurden mutmaĂlich auf die höhere SensitivitĂ€t von Cystatin C als Marker einer leichtgradig bis moderat eingeschrĂ€nkten eGFR zurĂŒckgefĂŒhrt. Da es sich bei der Arbeit um eine populationsbasierte Querschnittsstudie handelt, konnten Langzeitbeobachtungen sowie kausale oder pathophysiologische ZusammenhĂ€nge nicht geklĂ€rt werden. Die potenzielle Rolle von Ang-2, allein oder in Kombination mit Serum-Cystatin C, als Marker zur FrĂŒhdiagnostik von NierenbeeintrĂ€chtigungen oder CKD bleibt in weiteren Studien zu evaluieren.Background
An intact angiopoietin/Tie-2 ligand receptor system is indispensable for life. High circulating angiopoietin-2 (Ang-2) concentrations are strongly associated with kidney disease involving the progressive loss of glomerular filtration. The aim of our study was to investigate the associations between renal function and serum Ang-2 or serum Tie-2 concentrations in the general population.
Methods
Data of 3081 and 4088 subjects from two population-based studies, the Study of Health in Pomerania (SHIP-1) and SHIP-Trend, were used. Renal function was assessed by serum creatinine, cystatin C concentration, creatinine-based estimated glomerular filtration rate [eGFR(crea)], cystatin C-based eGFR [eGFR(cys)] and urinary albumin-to-creatinine ratio (uACR). Analyses of variance and linear regression models were calculated.
Results
In both cohorts, strong positive associations between serum cystatin C concentrations and serum Ang-2 or Tie-2 concentrations as well as inverse associations between eGFR(cys) and serum Ang-2 or Tie-2 concentrations were found. These relations were also present in a subpopulation without hypertension or diabetes mellitus type 2. Furthermore, we detected weak U-shaped associations between serum creatinine concentrations or eGFR(crea) and serum Ang-2 concentrations. With respect to uACR a strong positive association with serum Ang-2 concentrations was revealed.
Conclusion
Serum Ang-2 concentrations are strongly associated with sensitive parameters of renal impairment like serum cystatin C, uACR and eGFR(cys). These findings persisted even after exclusion of subjects with hypertension or diabetes mellitus type 2, conditions that predispose to chronic renal disease and are associated with increased Ang-2 concentrations. Interestingly, we did not detect the same strong relations between serum creatinine and eGFR(crea) with serum Ang-2 concentration. Additionally, significant association of serum Tie-2 concentrations with cystatin C and eGFR(cys) were detected
Nationaler RĂŒckstandskontrollplan â StĂ€rkung des Verbraucherschutzes durch gezielte Kontrollen bei tierischen Lebensmitteln
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