(C) 2009 Elsevier B.V. All rights reserved.”
“Introduction: The positron emission tomography (PET) tracer 9-[F-18]fluoroethyl-(+)-dihydrotetrabenazine ([F-18]-FE-(+)-DTBZ) is a potential candidate for quantifying beta-cell mass in vivo. The purpose was to investigate in vitro and in vivo utility of this tracer for the assessment of beta-cell mass.
Methods: Three pigs were intravenously administered [F-18]-FE-(+)-DTBZ and examined by PET/computed tomography. Binding parameters were estimated by kinetic modeling. In vitro k(D) and B-max were determined by saturation binding buy C646 studies of endocrine and exocrine human tissue homogenates. In vitro pancreatic uptake was determined
by tissue autoradiography with pancreases from patients with types 1 (T1DM) and 2 diabetes mellitus (T2DM) and healthy controls.
Results: [F-18]-FE-(+)-DTBZ had
a k(D) of 3.5 +/- 1.0 Selleckchem Fer-1 nM, a B-max of 382 +/- 108 fmol/mg protein and a specificity of 89+/-1.8% in islet homogenates. The total exocrine uptake was lower and 65% was nondisplaceable. No uptake difference was observed in pancreatic tissue slices from patients with T1DM, T2DM or healthy controls. The in vivo porcine pancreatic uptake reached a peak of standardized uptake value (SUV) of 2.8 with a low distribution volume ratio in all animals. Moderate to high tracer uptake was identified in the bile system and in bone.
Conclusions: [F-18]-FE-(+)-DTBZ binds to vesicular monoamine transporter 2 (VMAT2) with high specificity in pure islet tissue in vitro. However, there is high nondisplaceable binding to exocrine tissue. In addition, in vivo tracer metabolism and dehalogenation result in severe underestimation of porcine pancreatic VMAT2
expression and BCM. The results do not support [F-18]-FE-(+)-DTBZ as a suitable tracer for in vivo beta-cell imaging. (C) 2010 Elsevier Inc. All rights reserved.”
“A real-time reverse transcription loop-mediated isothermal amplification (real-time RT-LAMP) method was applied for detecting the replicase polyprotein-encoding gene of yellow head virus (YHV) in shrimp, Penaeus monodon. It is a novel, gene-specific assay that amplifies nucleic acid with high specificity, sensitivity and GBA3 rapidity under isothermal conditions using a set of six specially designed primers that recognize eight distinct sequences of the target gene. This method works with even low copies of DNA and is based on magnesium pyrophosphate turbidity detection by an inexpensive photometer for quantitative analysis. A user-friendly protocol was developed with optimal conditions standardized at 63 degrees C for 60 min. With this protocol, the assay sensitivity was 10 times higher than the widely used YHV nested RT-PCR system. Cross-reactivity analysis using other shrimp virus DNA/cDNA and YHV-negative shrimp demonstrated high specificity of the assay.