Equine skeletal scintigraphy: Comparing lesion detection ability of methylene diphosphonate and hydroxymethylene diphosphonate in the caudal cervical and proximal metacarpal/metatarsal regions.

Background: Data regarding the lesion detection ability of different radiotracers are lacking in equine bone scintigraphy.

Methods: In this prospective study, hydroxymethylene diphosphonate (HMDP) and methylene diphosphonate (MDP) were compared in horses with increased radiopharmaceutical uptake either in the caudal cervical region (CS group) or in the proximal metacarpal/metatarsal region (PMR group). Region of interest analysis was used to determine normal bone-to-soft tissue ratios, lesion-to-normal bone ratios and lesion-to-soft tissue ratios.

Evaluation of cartilage injury in horses with osteochondral fragments in the metacarpo-/metatarsophalangeal joint: A study on 823 arthroscopies.

Background: Osteochondral fragment removal is commonly performed but there are little scientific data supporting this procedure in the absence of clinical signs. More information is needed to facilitate clinical decision-making regarding fragment removal of the metacarpo-/metatarsophalangeal joint.

Objectives: To assess prevalence of cartilage injury in the equine metacarpo-/metatarsophalangeal joint and its association to fragment size, location, age and lameness.

Thoracic processi spinosi findings agree among subjective, semiquantitative, and modified semiquantitative scintigraphic image evaluation methods and partially agree with clinical findings in horses with and without thoracolumbar pain.

Impinging processi spinosi in the equine thoracic spine are a common cause of poor performance in the horse. A modified semiquantitative scintigraphic image analysis has been proposed for the evaluation of equine processi spinosi. This technique showed a high inter- and intraobserver agreement when compared to subjective and semiquantitative image analysis.

Semi-quantitative methods yield greater inter- and intraobserver agreement than subjective methods for interpreting technetium-hydroxymethylene-diphosphonate uptake in equine thoracic processi spinosi.

Scintigraphy is a standard diagnostic method for evaluating horses with back pain due to suspected thoracic processus spinosus pathology. Lesion detection is based on subjective or semi-quantitative assessments of increased uptake. This retrospective, analytical study is aimed to compare semi-quantitative and subjective methods in the evaluation of scintigraphic images of the processi spinosi in the equine thoracic spine.

An international multi-centre prospective study on the efficacy of an intraarticular polyacrylamide hydrogel in horses with osteoarthritis: a 24 months follow-up.

Background: Polyacrylamide hydrogel (PAAG) was evaluated recently to treat osteoarthritis (OA) in horses with highly encouraging results; however no long term field-study was done to explore its clinical efficacy and lasting effect. The objective of this study was to evaluate the efficacy of PAAG in improving clinical signs of OA in horses. We hypothesized that lameness grade would significantly improve and the effect would last at least 2 years in osteoarthritic joints treated with PAAG.

The association of actin and myosin in the presence of gamma-amido-ATP proceeds mainly via a complex with myosin in the closed conformation.

The interaction of gamma-amido-ATP (ATPN) and its 2'(3')-O-methylanthraniloyl derivative (mantATPN) with skeletal myosin subfragment 1 (S1) and actomyosin (actoS1) was studied in stopped-flow experiments. Tryptophan fluorescence and fluorescence of the mant label or light scattering were measured simultaneously. Information about the binding of mant nucleotides was obtained from the quenching of tryptophan fluorescence by the mant label.

Electron cryo-microscopy shows how strong binding of myosin to actin releases nucleotide.

Muscle contraction involves the cyclic interaction of the myosin cross-bridges with the actin filament, which is coupled to steps in the hydrolysis of ATP. While bound to actin each cross-bridge undergoes a conformational change, often referred to as the "power stroke", which moves the actin filament past the myosin filaments; this is associated with the release of the products of ATP hydrolysis and a stronger binding of myosin to actin. The association of a new ATP molecule weakens the binding again, and the attached cross-bridge rapidly dissociates from actin.

Synthesis, characterization and application of two nucleoside triphosphate analogues, GTPgammaNH(2) and GTPgammaF.

Guanosine triphosphate nucleotide analogues such as GppNHp (also named GMPPNP) or GTPgammaS are widely used to stabilize rapidly hydrolyzing protein-nucleotide complexes and to investigate biochemical reaction pathways. Here we describe the chemical synthesis of guanosine 5'-O-(gamma-amidotriphosphate) (GTPgammaNH(2)) and a new synthesis of guanosine 5'-O-(gamma-fluorotriphosphate) (GTPgammaF). The two nucleotides were characterized using NMR spectroscopy and isothermal titration calorimetry.

Gamma-amido-ATP stabilizes a high-fluorescence state of myosin subfragment 1.

On binding to myosin subfragment 1 (S1), the gamma-amido derivative of ATP (ATPgammaNH2), an isomer of adenosine 5'-[beta,gamma-imido]-triphosphate (AMPPNP), induces a larger increase in the intrinsic (tryptophan) fluorescence than is seen with ATP. A binding constant of 1.7x10(7) M(-1) was measured for ATPgammaNH2, compared to 2.