Practicable determination of the glomerular filtration rate (GFR) in dogs with a two-step-method

Deckblatt-Impressum persönlicher Dank Inhaltsverzeichnis Abkürzungsverzeichnis Einleitung Literaturübersicht Material und Methoden Ergebnisse Diskussion Zusammenfassung Summary Literaturverzeichnis Danksagung Lebenslauf SelbständigkeitserklärungEinleitung Die Früherkennung von renalen Funktionsstörungen beim Hund noch im subklinischen Bereich ist anhand klinischer Symptome und labordiagnostischer Daten bisher nicht möglich. Daher besteht die Forderung nach einer möglichst frühzeitigen Diagnostik der renalen Malfunktion, z. B. bei der unheilbaren und progredient verlaufenden chronischen Niereninsuffizienz. Bisher existieren zur Feststellung einer Azotämie sehr unterschiedliche Angaben für Grenzwerte der Serum-[Kreatininendo]. Material und Methoden Es wurden insgesamt n = 331 Hunde beiderlei Geschlechts (männlich: n = 162 (48,9 %), weiblich: n = 169 (51,1 %)) im Alter von 7 (3,0 - 9,1) Jahren in die Untersuchungen einbezogen. Die Tiere gehörten 57 verschiedenen Rassen an. Am häufigsten waren Mischlinge (n = 93 (28 %)) vertreten. Für die Ermittlung der Kreatinin - Wiederauffindungsrate wurde das Substrat Kreatinin vergleichend entweder mit dem kinetischen Farbtest nach Jaffé oder mit dem Enzym Kreatininase analysiert. Die Bestimmung der GFR geschah mit dem renalen Funktionstest mittels P-CLterminal von exogenem Kreatinin. Die Grenzwertbestimmung der Serum-[Kreatininendo] und die qualitative GFR-Bestimmung erfolgten mittels der ROC-Analytik. Ergebnisse Im Bereich bis 884 µmol/l (10 mg/dl) betrug die Wiederauffindungsrate für Kreatinin im Hundeserum durchschnittlich 99,2 % bei der Jaffé-Methode und 99,4 % für das enzymatische Verfahren. Im Bereich von 804 - 4.420 µmol/l (9,1 - 50 mg/dl) wird die Kreatininkonzentration mit dem enzymatischen Verfahren um durchschnittlich 1 - 2 % unterbewertet und mit der Jaffé - Methode durchschnittlich um 3 - 4 % überbewertet. Im Konzentrationsbereich von 804 - 4.420 µmol/l ergaben sich bei der Verdünnung von 1:10 mit Aqua dest. eine Wiederauffindungsrate für die Jaffé - Methode von 87,7 % und für das enzymatische Verfahren von 97,7 %. Die mit einem renalen Funktionstest ermittelte GFR der Probanden wurde mit insgesamt 25 verschiedenen labordiagnostischen Blut- und Harnparametern verglichen (n = 89 Hunde). Erst bei der stark reduzierten GFR auf ≤ 40 % der Norm bestanden für einige Parameter labordiagnostisch verwertbare Veränderungen vom jeweiligen Referenzbereich. Von allen untersuchten Parametern korrelierte die Serum-[Kreatininendo] am besten mit der GFR (n = 300 Hunde). Nach Ermittlung der GFR der Tiere konnte der in der Literatur sehr unterschiedlich angegebene Grenzwert für die Serum-[Kreatininendo] neu festgelegt werden (n = 300 Hunde). Er betrug 171 µmol/l für die Diagnostik der pathologisch erniedrigten GFR von ≤ 30 % der Norm. Hierbei lagen die diagnostische Sensitivität bei durchschnittlich 100 % und die Spezifität bei 99 %. Als Kompromiss zwischen der in der Praxis geforderten möglichst frühen Diagnostik der renalen Malfunktion und einer noch ausreichenden diagnostischen Qualität wurde die GFR ≤ 40 % der Norm gewählt. Ab einem Grenzwert von 144 µmol/l detektiert die Serum-[Kreatininendo] diesen definierten Zustand der renalen Mafunktion. Die diagnostische Sensitivität beträgt dann 89 % und die Spezifität 97 %. Die Verteilung von exogen zugeführtem Kreatinin ist bei nierengesunden und nierenkranken Hunden innerhalb von zwei Stunden abgeschlossen (n = 31 Hunde). Es wurde eine Vereinfachung des renalen Funktionstests zur qualitativen Unterscheidung der Hunde in nierengesund (GFR > 70 %) und nierenkrank (GFR ≤ 70 %) mit nur insgesamt zwei Blutproben untersucht (n = 89 Hunde). In den Zeiträumen 2 - 3 und 3 - 4 h nach der Applikation des exogenen Kreatinins war eine qualitative Unterscheidung der Hunde nicht möglich. Abweichend davon gelang mit den wesentlich späteren Zeiträumen, wie 6 - 7 und 7 - 7,5 h nach Markerzufuhr, die Bestimmung der beeinträchtigten Nierenfunktion mit zufrieden stellender diagnostischer Qualität. Mit einer AUC von 0,972 besaß die Serum-[Kreatiningesamt] im Zeitraum 7 - 7,5 h nach Kreatiningabe die größte diagnostische Sicherheit zur Unterscheidung der Hunde in nierengesund und nierenkrank . Die Serum-[Kreatiningesamt] lieferte eindeutig bessere Ergebnisse als die Serum-[Kreatininexo]. Eine Blutprobenentnahme vor der Kreatininzufuhr ist bei dieser Art der Testdurchführung überflüssig. Die ermittelte Grenze für die Serum-[Kreatiningesamt] liegt bei 270 µmol/l. Zusammenfassend gilt für Hunde, deren Serum-[Kreatiningesamt] sich im Zeitraum 7 - 7,5 h nach entsprechend dosierter Markerzufuhr noch im Bereich über 270 µmol/l befindet, dass sie eine GFR von ≤ 70 % der Norm besitzen. Diese Tiere sind daher als nierenkrank zu bezeichnen. Schlussfolgerungen \- Mit der Jaffé - Methode können Kreatininkonzentrationen bis zu 2.600 µmol/l (30 mg/dl) im Serum von Hunden zuverlässig bestimmt werden \- Bei Serum - Kreatininkonzentrationen > 2.600 µmol/l (30 mg/dl) sollte die Bestimmung mittels enzymatischem Verfahren erfolgen, eine Verdünnung der Probe ist nicht notwendig. \- Eine Frühdiagnostik der renalen Malfunktion anhand der hier untersuchten 25 verschiedenen labordiagnostischen Parameter in Blut und Harn gelingt nicht mit ausreichender diagnostischer Sicherheit und kann deshalb nicht empfohlen werden. \- Zur Diagnose einer Azotämie mit der GFR von ≤ 40 % wird als obere Grenze die physiologische Serum-[Kreatininendo] von 144 µmol/l empfohlen. Die diagnostische Sicherheit ist mit der Sensitivität von 89 % und der Spezifität von 97 % beachtlich hoch. \- Die Verteilung des exogen zugeführten Kreatinins ist sowohl bei nierengesunden als auch bei nierenkranken Hunden innerhalb von zwei Stunden nach Markerzufuhr abgeschlossen. \- Zur Vereinfachung der Bestimmung einer renalen Malfunktion können Hunde den Marker exogenes Kreatinin in der Dosierung 2 g/m2 KOF i.v. bzw. s.c. oder in der Dosierung 4 g/m2 KOF oral erhalten. Demnach ist im Zeitraum von 7 - 7,5 h eine einmalige Blutprobe mit Bestimmung der Serum-[Kreatiningesamt] erforderlich. Hunde mit einer Serum-[Kreatiningesamt] > 270 µmol/l sind als nierenkrank (GFR ≤ 70 % der Norm) einzustufen.Introduction The early determination of renal dysfunction in dogs on the basis of clinical symptoms or laboratory diagnostic tests is difficult. There is thus a need for a simple diagnostic test to determine renal dysfunction in the early state, for instance in incurable and progressive renal failure. Moreover, the establishment of an azotaemia in the dog has been difficult, due to the variability of the upper reference value for the serum creatinine concentration. Material and methods A total number of 331 dogs of both genders (male: n = 162 (48.9 %), female: n = 169 (51.1 %)) and median age of 7 (3.0 - 9.1) years were included in the investigation. The dogs belonged to 57 different breeds; mixed-breed dogs (n = 93 (28 %)) were in the majority. For the determination of the creatinine-recovery-rate, the substrate creatinine was analysed either with the kinetic colour test of Jaffé or with the enzyme creatininase. The GFR was determined with the renal function test using the terminal plasma-clearance of exogenous creatinine. For the determination of the limiting value and the qualitative determination of the GFR, the ROC- analysis method was used. Results Up to 884 µmol/l (10 mg/dl), the determination rate for creatinine in the serum of dogs was on average 99.2 % for the Jaffé-method and 99.4 % for the enzymatic method. In the range from 804 - 4,420 µmol/l (9.1 - 50 mg/dl), the creatinine concentration was underestimated by about 1 - 2 % with the enzymatic method and overestimated by about 3 - 4 % with the Jaffé-method. If the serum was diluted 1 to 10 with distilled water in the concentration range from 804 - 4,420 µmol/l, there was a determination rate of 87.7 % for the Jaffé method and 97.7 % for the enzymatic method. The estimated GFR of each dog with the renal function test was compared with 25 different laboratory blood- and urinary parameters (n = 89 dogs). Only when the GFR was reduced to below 40 % of the normal range were there significant changes in some of the laboratory parameter. From all measured parameters, the best correlation was between the endogenous serum- creatinine concentration and the GFR (n = 300 dogs). These results for GFR in the dogs allowed a new definition for the upper limit of the endogenous serum- creatinine concentration. For GFR of 30% or less of the normal range this was 171 µmol/l. The diagnostic sensitivity was 100% and the specificity 99%. As a compromise between the earliest diagnosis of renal failure and a sufficient diagnostic quality, a GFR of less than 40% of the reference range was chosen. An upper limit of144 µmol/l for the endogenous serum-creatinine concentration detects this level of renal failure. The diagnostic sensitivity is 89% and the specificity 97%. The distribution of exogenous creatinine is completed within two hours in both normal and in dogs with renal disease. A simplification of the renal function test to distinguish qualitatively between healthy and diseased dogs using only two blood samples was tested (n = 89 dogs). In the time interval between 2 - 3 h and 3 - 4 h after giving exogenous creatinine, the qualitative differentiation between normal and diseased dogs was impossible. However, the determination of reduced renal function is possible with a satisfactory diagnostic quality at later times of between 6 - 7 h and 7 - 7.5 hours after giving creatinine. With an area under the curve (AUC) of 0,972, the total serum-creatinine concentration showed, in the time interval between 7 - 7.5 h after giving creatinine the greatest diagnostic certainty in the differentiation between healthy and diseased dogs. The total serum- creatinine concentration showed better results than the exogenous serum- creatinine concentration. For this test, a blood sampling before giving creatinine is unnecessary. The estimated upper limit for the total serum- creatinine concentration is 270 µmol/l. In summary, dogs with a total serum- creatinine of over 270 µmol/l in the time interval 7 - 7.5 h after an exactly dosed marker have a GFR ≤ 70 % of the normal range. These dogs have renal disease. Conclusions \- With the Jaffé-method, creatinine concentrations up to 2,600 µmol/l (30 mg/dl) can be measured reliably in the serum of dogs \- Creatinine-concentrations over 2,600 µmol/l should be determined with the enzymatic method; a dilution is not necessary \- An early diagnosis of renal dysfunction using 25 different laboratory parameters in blood and urine was not possible with a sufficient diagnostic certainty.Such tests cannot be recommended. \- For the diagnosis of an azotaemia with the GFR ≤ 40 %, the physiological serum-creatinine concentration of 144 µmol/l is recommended as the upper limit. The diagnostic safety is high with a sensitivity of 89 % and a specificity of 97 %. \- The distribution of the exogenous creatinine is completed within two hours after marker application in both healthy and diseased dogs. \- To simplify the determination of renal function, the dogs received exogenous creatinine i.v. or s.c. in a dosage of 2 g/m2 body surface area (BSA) or orally in a dosage of 4 g/m2 BSA. Only one blood sample for the determination of the total serum-creatinine concentration in the time interval between 7 - 7.5 h is necessary. Dogs with a total serum-creatinine concentration > 270 µmol/l are nephrologically sick (GFR ≤ 70 % of the reference range)

The cultural adaptation of quantity judgment tasks in Ghanaian English and Akan

The phenomenon of mass and countability is multifaceted and has been controversially discussed in many disciplines. For linguistics, differences in the morphosyntactic marking of the distinction cross-linguistically, and its cross-cultural ontological-semantic conceptualization are particularly interesting. However, most studies into mass and countability have focused on (American) English, and, to some extent European and Asian languages. African languages and contexts have as yet been neglected by researchinto countability, and the methodological tools employed to study it do not account for the ambient cultural contexts. This paper presents the results of a quantity judgment task designed according to Barner and Snedeker’s (2005) experiment for American English speakers, conducted in Ghanaian English and Akan. The Ghanaian experiments reveal important concerns regarding the stimuli and their applicability, especially to Akan culture. Thus, inspired by other studies into the semantics of Akan, a new set of stimuli is suggested in order to investigate mass and countability contrastively in Ghanaian English and Akan. In this vein, they emphasize the insufficiency of translations with regard to (psycho)linguistic experiments and the importance of proper cultural adaptation

“For explorers by explorers”: A discursive analysis of cruise tourism in Norway

The Norwegian company Hurtigruten operates ships cruising along the Norwegian coast and has played an important role in tourism for over a century. This article provides a multimodal discourse analysis of the website advertising Hurtigruten’s most popular journey, drawing on a critical tourism studies approach. It aims to answer the question as to what central themes emerge in tourism discourse on Norway, targeted at an international audience. Central characteristics of tourism discourse (Dann 1996), i.e., strangerhood, conflict, authenticity, and playfulness, are shown to be crucial in the analysed material. The paper discusses the notion of authenticity as a performative strategy in the promotion of Norwegian cruise tourism. One central aim of this paper is finding out what and how the notion of “authentically Norwegian” is advertised. The results imply that these topics, and especially the notion of authenticity, are aligned with general tourism imaginaries, which are similar globally.         &nbsp

Phonology of hunting signs in two Kalahari-Khoe speaking groups (Ts'ixa and ||Ani)

Phonology of hunting signs in two Kalahari-Khoe speaking groups (Ts'ixa and ||Ani

Substitution of the native <i>srfA</i> promoter by constitutive P<i>veg</i> in two <i>B. subtilis </i>strains and evaluation of the effect on surfactin production

The genetic enhancement of Surfactin production increasingly gained attention in the last years, since relatively low product yields limit the industrial application of this biosurfactant. The natural quorum sensing regulation of the srfA operon (coding for the Surfactin synthetase) can reasonably be assumed to be the bottleneck of Surfactin synthesis. Therefore, the replacement of the naturally quorum sensing regulated, and herewith cell density dependent, promoter PsrfA against the Bacillus subtilis endogenous and constitutive promoter Pveg was hypothesized to generally enhance Surfactin yields. The markerless promoter replacement was conducted in the two B. subtilis Surfactin producer strains 3A38 and DSM 10T. The promoter substitution led to an enhancement of Surfactin concentrations in the producer strain 3A38, initially producing only minor amounts of Surfactin (0.07 g/L increased to 0.26 g/L). In contrast, promoter exchange in B. subtilis DSM 10T (wild-type strain producing 0.62 g/L Surfactin) did not achieve an enhancement of Surfactin concentrations (detrimental reduction to 0.04 g/L). These findings implicate that Surfactin synthesis is differently regulated in minor and strong Surfactin producer strains. The hypothesized general enhancement of Surfactin yields after substitution of the native promoter was therefore not confirmed

The presence of infection-related antiphospholipid antibodies in infective endocarditis determines a major risk factor for embolic events

AbstractOBJECTIVESThe impact of infection-associated antiphospholipid antibodies (APA) on endothelial cell activation, blood coagulation and fibrinolysis was evaluated in patients with infective endocarditis with and without major embolic events.BACKGROUNDAn embolic event is a common and severe complication of infective endocarditis. Despite the fact that APAs are known to be associated with infectious diseases, their pathogenic role in infective endocarditis has not been clearly defined.METHODSThe relationship among the occurrence of major embolic events, echocardiographic vegetation size, endothelial cell activation, thrombin generation, fibrinolysis and APA was examined in 91 patients with definite infective endocarditis, including 26 patients with embolic events and 65 control subjects without embolic events.RESULTSOverall, 14.3% of patients exhibited elevated APA levels. Embolic events occurred more frequently in patients with elevated levels of APA than in patients without (61.5% vs. 23.1%; p = 0.008). Patients with elevated levels of APA showed higher levels of prothrombin-fragment F1+2 (p = 0.005), plasminogen-activator inhibitor 1 (p = 0.0002), von Willebrand factor (p = 0.002) and lower levels of activated protein C (p = 0.001) than patients with normal levels of APA. Thrombin generation and endothelial cell activation were both positively correlated with levels of APA. The occurrence of elevated APA levels was frequently associated with structural valve abnormalities (p = 0.01) and vegetations >1.3 cm (p = 0.002).CONCLUSIONSInfection-associated elevated APA levels in patients with infective endocarditis are related to endothelial cell activation, thrombin generation and impairment of fibrinolysis. This may contribute to the increased risk for major embolic events in these patients

Transmembrane chemical absorption process for recovering ammonia as an organic fertilizer using citric acid as the trapping solution

Membrane contactors are among the available technologies that allow a reduction in the amount of ammoniacal nitrogen released into the environment through a process called transmembrane chemical absorption (TMCA). This process can be operated with different substances acting as trapping solutions; however, strong inorganic acids have been studied the most. The purpose of this study was to demonstrate, at laboratory scale, the performance of citric acid as a capturing solution in TMCA processes for recovering ammonia as an organic fertilizer from anaerobic digestor reject water using membrane contactors in a liquid-liquid configuration and to compare it with the most studied solution, sulfuric acid. The experiments were carried out at 22 °C and 40 °C and with a feed water pH of 10 and 10.5. When the system was operated at pH 10, the rates of recovered ammonia from the feed solution obtained with citric acid were 10.7-16.5 percentage points (pp) lower compared to sulfuric acid, and at pH 10.5, the difference decreased to 5-10 pp. Under all tested conditions, the water vapor transport in the system was lower when using citric acid as the trapping solution, and at pH 10 and 40 °C, it was 5.7 times lower. When estimating the operational costs for scaling up the system, citric acid appears to be a better option than sulfuric acid as a trapping solution, but in both cases, the process was not profitable under the studied conditions.This research was funded by the European Union Commission through the European Regional Development Fund (ERDF) (Bioök_2076348) and the Ministry of Environment, Climate Protection and the Energy Sector of the federal state of Baden Württemberg, Germany. The APC was funded by the Fraunhofer Society.European Union CommissionMinistry of Environment, Climate Protection and the Energy Sector of the federal state of Baden Württemberg, GermanyFraunhofer Societ

Involvement of the epidermal growth factor receptor in the modulation of multidrug resistance in human hepatocellular carcinoma cells in vitro

<p>Abstract</p> <p>Background</p> <p>Hepatocellular carcinoma (HCC) is a molecular complex tumor with high intrinsic drug resistance. Recent evidence suggests an involvement of the tyrosine kinase pathway in the regulation of ATP-binding cassette protein (ABC-transport protein) mediated multidrug resistance in cancer cells. The aim of this study was to examine whether EGFR inhibition sensitizes HCCs to chemotherapy and to elucidate its mechanism.</p> <p>Results</p> <p>Chemotherapeutic treatment induces multidrug resistance and significantly increases ABC-transport protein expression and function in a time- and dose-dependent manner in HCC cells. Furthermore, cytostatic treatment increases the mRNA expression of tyrosine kinases and induces the phosphorylation of ERK. EGF activation of the tyrosine kinase pathway up-regulated the ABC-transport protein mRNA expression and enhanced the survival of resistant HCC cells. Consistent with these effects, inhibition of the EGFR using siRNA decreased the ABC-transport protein mRNA expression and inhibited the proliferation of resistant cells. Additional treatment with Gefitinib, a clinically approved EGFR inhibitor, caused a dose-dependent reversal of resistance to conventional chemotherapy.</p> <p>Conclusion</p> <p>The present study demonstrates that the multidrug resistance of HCC is modulated through the EGF-activated tyrosine kinase cascade. Consequentially, the restoration of chemosensitivity by EGFR inhibition may lead towards new tailored therapies in patients with highly resistant tumors.</p