Effects of exercise vs experimental osteoarthritis on imaging outcomes

SummaryObjectiveTo identify changes in imaging outcomes in a controlled model of osteoarthritis (OA) vs exercise.MethodSixteen 2-year-old horses were randomly assigned to an exercise control (n=8) or an exercise OA (n=8) group. All horses had middle carpal joints arthroscopically explored and an osteochondral fragment was induced in one middle carpal joint of the OA group. All horses were treadmill exercised for the duration of the study (91 days). Clinical, radiographic, nuclear scintigraphic, computed tomographic and magnetic resonance imaging (MRI) examinations were performed and outcomes of these were compared between groups. Imaging results were correlated to clinical, biomarker and gross pathologic results.ResultsThe OA group had significant increases in clinical outcomes and most imaging parameters. Specifically, the OA group showed significant increases in radiographic lysis and nuclear scintigraphic uptake. There was very little change in subchondral bone density, but a significant change in subchondral bone edema. Radiographic lysis, radial carpal bone edema and nuclear scintigraphy were strongly correlated with clinical changes and radial carpal bone edema was strongly correlated with changes in Type I and Type II collagen found in the synovial fluid.ConclusionsOA induced significant changes in imaging parameters beyond the adaptation seen with exercise. Bone edema detected with MRI was closely correlated with collagen biomarkers detected in the synovial fluid

Dynamic three-dimensional computed tomographic imaging facilitates evaluation of the equine cervical articular process joint in motion

Background Dynamic computed tomography (CT) imaging has been introduced in human orthopaedics and is continuing to gain popularity. With dynamic CT, video sequences of anatomical structures can be evaluated in motion. Objectives To investigate the feasibility of dynamic CT for diagnostic imaging of the equine cervical articular process joints (APJs) and to give a detailed description of the APJ movement pattern. Study design Descriptive cadaver imaging. Methods Cervical specimens of twelve Warmblood horses were included. A custom-made motorised testing device was used to position and manipulate the neck specimens and perform dynamic 2D and 3D CT imaging. Images were obtained with a 320-detector-row CT scanner with a 160 mm wide-area (2D) solid-state detector design that allows image acquisition of a volumetric axial length of 160 mm without moving the CT couch. Dynamic videos were acquired and divided into four phases of movement. Three blinded observers used a subjective scale of 1 (excellent) to 4 (poor) to grade the overall image quality in each phases of motion cycle. Results With an overall median score of 1 the image quality, a significantly lower score was observed in the dynamic 3D videos over the four phases by the three observers compared with the 2D videos for both flexion (3D 95% CI: 1-2 and 2D 95% CI: 1-3; P = .007) and extension movement (3D 95% CI: 1-2 and 2D 95% CI: 1-3; P = .008). Median Translational displacement of the APJ surface was significantly greater in flexion than in extension movement (P = .002). Main limitations The small number of specimens included. Excision of spines and removal of musculature. Conclusions The study is a first step in the investigation of the potential of dynamic 3D CT in veterinary medicine, a technique that has only begun to be explored and leaves much room for refinement prior to its introduction in routine practice. CT with a detector coverage of 16 cm and a rotation speed of 0.32 seconds provides high-quality images of moving objects and gives new insight into the movement pattern of equine cervical APJs

Improving product yields on D-glucose in Escherichia coli via knockout of pgi and zwf and feeding of supplemental carbon sources

The use of lignocellulosic biomass as a feedstock for microbial fermentation processes presents an opportunity for increasing the yield of bioproducts derived directly from glucose. Lignocellulosic biomass consists of several fermentable sugars, including glucose, xylose, and arabinose. In this study, we investigate the ability of an E. coli Δpgi Δzwf mutant to consume alternative carbon sources (xylose, arabinose, and glycerol) for growth while reserving glucose for product formation. Deletion of pgi and zwf was found to eliminate catabolite repression as well as the ability of E. coli to consume glucose for biomass formation. In addition, the yield from glucose of the bioproduct D-glucaric acid was significantly increased in a Δpgi Δzwf strain.National Science Foundation (U.S.). Synthetic Biology Engineering Research Center (Grant EEC-0540879)National Science Foundation (U.S.) (CAREER Award CBET-0954986)National Institutes of Health (U.S.). Biotechnology Training Program (Grant T32GM008334

Effect of scan plane and arthrography on visibility and inter-observer agreement of the equine distal sesamoidean impar ligament on magnetic resonance images

In magnetic resonance imaging (MRI) examinations, moderate to severe changes of the distal sesamoidean impar ligament (DSIL) were found in horses with lameness localized to their feet. Histologic abnormalities were detected more commonly in lame horses. Because of its heterogeneity and small thickness, evaluation of the DSIL in MRI can be challenging. The aim of the study was to determine the optimal sequence and the ideal transverse perpendicular angle for visualization of the DSIL before and after arthrography of the distal interphalangeal joint (DIPJ). Twenty-five cadaver forelimbs were examined with low-field MRI. Sagittal, frontal, and three different angled transverse planes were obtained before and after arthrography of the DIPJ. All planes were acquired in T1w (weighted) Gradient Recall Echo (GRE), T2∗w GRE, T2w Fast Spin Echo (FSE), and Short Tau Inversion Recovery (STIR) FSE and visualization of the DSIL was scored by two observers. Visualization of the DSIL was best on sagittal T2w FSE and STIR FSE images. All transverse planes were inferior compared with sagittal sequences. After arthrography of the DIPJ, visualization of the DSIL origin improved in sagittal T2w FSE sequences, and agreement between observers increased for sagittal T2w FSE and STIR FSE images. Sagittal T2w FSE and STIR FSE images allowed good visualization of the DSIL in low-field MRI. Visualization of the DSIL did not improve for altered angled transverse sequences but increased with arthrography of the DIPJ. Subjective influence between different observers was found but decreased with DIPJ arthrography

A transcription factor-based biosensor for detection of itaconic acid

Itaconic acid is an important platform chemical that can easily be incorporated into polymers and has the potential to replace petrochemical-based acrylic or methacrylic acid. A number of microorganisms have been developed for the biosynthesis of itaconate including Aspergillus terreus, Escherichia coli and Saccharomyces cerevisiae. However, the number of strains and conditions that can be tested for increased itaconate titers are currently limited due to the lack of high-throughput screening methods. Here we identified itaconate-inducible promoters and their corresponding LysR-type transcriptional regulators from Yersinia pseudotuberculosis and Pseudomonas aeruginosa. We show that the YpItcR/Pccl inducible system is highly inducible by itaconic acid in the model gammaproteobacterium E. coli and the betaproteobacterium Cupriavidus necator (215- and 105-fold, respectively). The kinetics and dynamics of the YpItcR/Pccl inducible system are investigated and we demonstrate, that in addition to itaconate, the genetically encoded biosensor is capable of detecting mesaconate, cis-, and trans-aconitate in a dose-dependent manner. Moreover, the fluorescence-based biosensor is applied in E. coli to identify the optimum expression level of cadA, the product of which catalyzes the conversion of cis-aconitate into itaconate. The fluorescence output is shown to correlate well with itaconate concentrations quantified using high-performance liquid chromatography coupled with ultraviolet spectroscopy. This work highlights the potential of the YpItcR/Pccl inducible system to be applied as biosensor for high-throughput microbial strain development to facilitate improved itaconate biosynthesis

Conformal sulfated zirconia monolayer catalysts for the one-pot synthesis of ethyl levulinate from glucose

Here we describe a simple route to creating conformal sulphated zirconia monolayers throughout an SBA-15 architecture that confers efficient acid-catalysed one-pot conversion of glucose to ethyl levulinate