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Abstract 1 1 Maximum residue limit (MRL), tulathromycin marker residue (TLM), European Union (EU), liquid chromatography-tandem mass spectrometry (LC-MS/MS), liquid chromatography (LC), electrospray ionization (ESI), selected reaction monitoring (SRM), polypropylene (PP), limit of detection (LOD), limit of quantification (LOQ), relative standard deviation (RSD). A reliable and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method was developed to quantify total tulathromycin residues in bovine tissues. Specifically, the above method relied on the quantification of CP-60,300, a marker produced by tulathromycin hydrolysis, for which maximum residue limits (MRLs) were established by the European Union and several other countries. Sample preparation and LC-MS/MS conditions were thoroughly optimized to allow for accurate quantification. The optimized procedure involved sample homogenization with 2 mol/L hydrochloric acid and ethyl acetate, heating of the resulting aqueous layer to convert tulathromycin and its metabolites into the marker residue, cleanup by a polymer-based cation-exchange cartridge, and subsequent analysis by LC-MS/MS. The developed method was validated for tulathromycin A and the marker residue in bovine muscle, fat, and liver at two levels, namely at the MRL set in Japan and at 0.01 mg/kg. Excellent analytical performance was observed, with the average recoveries of tulathromycin A and the marker residue ranging from 98 to 107%, and relative standard deviations ranging from 1 to 3%. Matrix effects were negligible, and analyte loss during sample preparation was minimal for all matrices tested, which allowed for accurate determination by external standard calibration using a solvent standard. No interfering peaks were observed close to the retention time of the marker residue for all matrices, which was indicative of high specificity. Overall, the developed method was proven suitable for regulatory purpose analysis of total tulathromycin residues. Highlights • LC-MS/MS method for the determination of total tulathromycin residues is developed. • Hydrolyzed marker residue CP-60,300 is used for tulathromycin residue analysis. • Sample preparation and LC-MS/MS conditions are carefully optimized. • The developed method shows excellent analytical performance. • Accurate quantification is achieved by external calibration using solvent standards. [ABSTRACT FROM AUTHOR]

The proliferation and differentiation of skeletal muscle satellite cells is regulated by multiple regulatory factors including non-coding RNAs. It has been reported that miR-133b regulates myogenesis. In this study, we detected a novel lncRNA, lnc133b, which is completely complemented by mature miR-133b, indicating that lnc133b may regulate the expression of miR-133b by “sponge” miR-133b. A luciferase report assay confirmed that lnc133b interacts with miR-133b in regions complemented by miR-133b. We successfully constructed lnc133b gain/loss-of-function cell models by infecting LV-1nc133b and transfecting si-lnc133b into satellite cells. Results of quantitative real-time polymerase chain reaction (qRT-PCR) and 5-ethynyl-2′-deoxyuridine (EdU) assays showed that overexpression or inhibition of lnc133b could promote the proliferation or inhibition of satellite cell differentiation. The qRT-PCR results also showed that lnc133b negatively regulates miR-133b expression and a Western blot assay showed that lnc133b positively regulates IGF1R expression, indicating that the lnc133b/miR-133b/IGF1R axis is a potential pathway for promoting satellite cell proliferation and repressing their differentiation through the ceRNA mechanism. Building on the findings of previous reports, we constructed the lnc133b/miR-133b/FGFR1 & PP2AC pathway to improve the lnc133b regulation network regulating the proliferation and differentiation of satellite cells. The current study provides a new perspective for understanding the mechanism regulating satellite cell proliferation and differentiation through the interaction of miR-133b and lnc133b. [ABSTRACT FROM AUTHOR]

Aim: This paper describes the rationale, development and clinical performance of a novel small-diameter vascular prosthesis of non-vascular animal tissue origin.Method: Durable conduits suitable for coronary and peripheral arterial reconstruction are prepared for the first time from non-vascular animal tissue. Australian bovine ureters from young steers from protected herds are processed to form strong, bloodflow-compatible and non-immunogenic biologic grafts (‘Flonova’R, Bionova International Pty Ltd, Melbourne). Fifty-six patients lacking suitable autogenous veins received 62 prostheses (32 bypasses were implanted above knee and 30 below knee). Determination of patency and function included Doppler ultrasound, duplex scanning and angiography.Findings: The primary patency rate at 1, 2 and 5 years, respectively was 67, 59 and 52% and the secondary patency for the same time frames was 88, 73 and 61%. There were no occlusions as a result of intimal hyperplasia. Dilatation of the wall was diagnosed in one prosthesis at 3.5 years, and one at 7 years, and a false aneurysm of unknown aetiology occurred in another at 3 months. There were no primary graft infections.Conclusion: This evaluation shows the chemically treated bovine ureter (CTBU) is a viable medium-term alternative to the currently available artificial vascular prostheses for peripheral revascularisation. [Copyright &y& Elsevier]