The phosphate transporter NaPi-IIa determines the rapid renal adaptation to dietary phosphate intake in mouse irrespective of persistently high FGF23 levels

Renal reabsorption of inorganic phosphate (Pi) is mediated by the phosphate transporters NaPi-IIa, NaPi-IIc, and Pit-2 in the proximal tubule brush border membrane (BBM). Dietary Pi intake regulates these transporters; however, the contribution of the specific isoforms to the rapid and slow phase is not fully clarified. Moreover, the regulation of PTH and FGF23, two major phosphaturic hormones, during the adaptive phase has not been correlated. C57/BL6 and NaPi-IIa−/− mice received 5days either 1.2% (HPD) or 0.1% (LPD) Pi-containing diets. Thereafter, some mice were acutely switched to LPD or HPD. Plasma Pi concentrations were similar under chronic diets, but lower when mice were acutely switched to LPD. Urinary Pi excretion was similar in C57/BL6 and NaPi-IIa−/− mice under HPD. During chronic LPD, NaPi-IIa−/− mice lost phosphate in urine compensated by higher intestinal Pi absorption. During the acute HPD-to-LPD switch, NaPi-IIa−/− mice exhibited a delayed decrease in urinary Pi excretion. PTH was acutely regulated by low dietary Pi intake. FGF23 did not respond to low Pi intake within 8h whereas the phospho-adaptator protein FRS2α necessary for FGF-receptor cell signaling was downregulated. BBM Pi transport activity and NaPi-IIa but not NaPi-IIc and Pit-2 abundance acutely adapted to diets in C57/BL6 mice. In NaPi-IIa−/−, Pi transport activity was low and did not adapt. Thus, NaPi-IIa mediates the fast adaptation to Pi intake and is upregulated during the adaptation to low Pi despite persistently high FGF23 levels. The sensitivity to FGF23 may be regulated by adapting FRS2α abundance and phosphorylatio

Längsschnittliche Entwicklung der neuromuskulären Leistungsfähigkeit von Nachwuchsfussballspielern

Hintergrund: Mit dem vermehrten Einzug des wissenschaftlich fundierten und systematischen Trainings in den modernen Spitzenfussball bekommen auch systematische Leistungstests immer grössere Bedeutung. Diese dienen zum einen zur Talentidentifikation im Scoutingprozess und zum andern auch zur Überprüfung der neuromuskulären Leistungsentwicklung der Nachwuchs- sowie Profifussballspieler. Die Leistungsentwicklung und mögliche Einflussfaktoren auf diese Entwicklung sollten optimiert werden, um das vorhandene Potential eines Spielers maximal ausschöpfen zu können. Diese möglichen Einflussfaktoren sollen in dieser Arbeit genauer untersucht werden. Methoden: Für die Untersuchung von verschiedenen Einflussfaktoren wurden, die in den letzten zwei Jahren systematisch erhobenen Leistungsdaten von Nachwuchsspielern des FC Basel 1893 analysiert. Die untersuchten Einflussfaktoren waren der Erhalt einer individuellen Ausbildungslösung, die Zugehörigkeit zu einer Nationalmannschaftsauswahl und die Eintrittsstufe in die Nachwuchsabteilung des FC Basel 1893. Diese Daten wurden mit einem Fragebogen erhoben. Anhand dieser Daten wurde mittels SPSS Statistics die Leistungsentwicklung über einen Zeitraum von zwei Jahren statistisch untersucht. Ergebnisse: Die Untersuchungen konnten keine eindeutigen Einflüsse der einzelnen Einflussfaktoren auf die neuromuskuläre Leistungsentwicklung über den untersuchten Zeitraum feststellen. Neben Tendenzen für die Leistungsentwicklung konnten auch Unterschiede in den Baseline-Leistungswerten beobachtet werden. Die Resultate sind aufgrund von verschiedenen Limitationen mit Vorsicht zu interpretieren. Schlussfolgerung: Die Daten des FC Basel 1893 haben grosses Potential, um die individuelle Leistungsentwicklung der jungen Talente tiefgründiger zu verstehen. In weiterführenden Untersuchungen mit angepassten Studiendesigns können diverse Einflussfaktoren identifiziert werden. Dadurch entsteht die Möglichkeit Spieler gezielter zu fördern und optimale Voraussetzungen für die sportliche sowie persönliche Entwicklung der Nachwuchsfussballer herzustellen

Application of a novel chemical assay for the quantification of endotoxins in bacterial bioreactor samples

A novel chemical assay, the so-called Kdo-DMB-liquid chromatography (LC) assay, was used for the accurate and cost-effective determination of the endotoxin content in supernatants of Gram-negative bacteria bioreactor samples. During mild acid hydrolysis, the endotoxin-specific sugar acid 3-deoxy-D-manno-oct-2-ulsonic acid (Kdo) is quantitatively released. Kdo is reacted with 1,2-diamino-4,5-methylenedioxybenzene (DMB) to obtain the highly fluorescent derivate Kdo-DMB. It is separated from the reaction mixture by reversed phase-(U)HPLC and detected by fluorescence. From the Kdo content the endotoxin content of the sample is calculated. For three batch cultivations of Escherichia coli K12 and a fed-batch cultivation of Pseudomonas putida KT2440, the evolution of the endotoxin content in dependence on the cultivation time was monitored. Under optimal, constant cultivation conditions a linear correlation between the endotoxin content and the easy-to-access bioreactor parameters optical density at 600 nm and dry cell weight was found for both endotoxin kinds. Under stress cultivation conditions the E. coli K12 cultivation showed a stronger increase of the endotoxin content at harvest in comparison to optimal conditions. Optical density and dry cell weight may be used for production reactors as an economic real-time estimation tool to determine the endotoxin content at different cultivation time points and conditions. The optical density can further be used to establish straightforward sample dilution schemes for endotoxin quantification in samples of unknown endotoxin content. The endotoxin content [ng mL-1] measured by the Kdo-DMB-LC assay and the endotoxin activity [EU mL-1] obtained by the compendial Limulus Amoebocyte Lysate assay show a high correlation for the bacterial bioreactor samples tested

Diagnostic utility of perilesional muscle edema in myositis ossificans

OBJECTIVES To investigate the value of extensive perilesional muscle edema for the differentiation between myositis ossificans (MO) and malignant intramuscular soft tissue tumors on MRI. MATERIALS AND METHODS Two blinded readers analyzed MR examinations of 90 consecutive patients with intramuscular soft tissue masses (group 1: MO, n = 20; group 2: malignant tumors, n = 70). Extent of edema around lesions was graded (0, none; 1, minimal edema; 2, moderate edema; 3, extensive edema). Edema-lesion ratio (ELR = ratio of the maximal diameter of the edema and the maximal diameter of the central lesion) was calculated. ROC analysis, Mann-Whitney U test, and Kappa test were used. RESULTS A total of 70% and 60% of patients with MO had edema grade 3 (reader 1/reader 2), 30%/40% edema grade 2. For the patients with malignant tumors, it was 2.9%/1.4% (edema grade 3) and 16%/23% (edema grade 2). Interrater reliability was substantial (kappa = 0.66). Extent of edema was significantly higher for patients of group 1 (p  2.0, sensitivity was 90% and specificity 91% for diagnosing MO. CONCLUSIONS Extensive perilesional muscle edema on MRI of more than double the size of the central lesion is highly specific, but not pathognomonic for myositis ossificans in the early/intermediate stage in the differentiation to malignant intramuscular soft tissue lesions

The phosphate transporter NaPi-IIa determines the rapid renal adaptation to dietary phosphate intake in mouse irrespective of persistently high FGF23 levels

Renal reabsorption of inorganic phosphate (Pi) is mediated by the phosphate transporters NaPi-IIa, NaPi-IIc, and Pit-2 in the proximal tubule brush border membrane (BBM). Dietary Pi intake regulates these transporters; however, the contribution of the specific isoforms to the rapid and slow phase is not fully clarified. Moreover, the regulation of PTH and FGF23, two major phosphaturic hormones, during the adaptive phase has not been correlated. C57/BL6 and NaPi-IIa(-/-) mice received 5 days either 1.2 % (HPD) or 0.1 % (LPD) Pi-containing diets. Thereafter, some mice were acutely switched to LPD or HPD. Plasma Pi concentrations were similar under chronic diets, but lower when mice were acutely switched to LPD. Urinary Pi excretion was similar in C57/BL6 and NaPi-IIa(-/-) mice under HPD. During chronic LPD, NaPi-IIa(-/-) mice lost phosphate in urine compensated by higher intestinal Pi absorption. During the acute HPD-to-LPD switch, NaPi-IIa(-/-) mice exhibited a delayed decrease in urinary Pi excretion. PTH was acutely regulated by low dietary Pi intake. FGF23 did not respond to low Pi intake within 8 h whereas the phospho-adaptator protein FRS2α necessary for FGF-receptor cell signaling was downregulated. BBM Pi transport activity and NaPi-IIa but not NaPi-IIc and Pit-2 abundance acutely adapted to diets in C57/BL6 mice. In NaPi-IIa(-/-), Pi transport activity was low and did not adapt. Thus, NaPi-IIa mediates the fast adaptation to Pi intake and is upregulated during the adaptation to low Pi despite persistently high FGF23 levels. The sensitivity to FGF23 may be regulated by adapting FRS2α abundance and phosphorylation