Effect of induced hindlimb length difference on body-mounted inertial sensor measures used to evaluate hindlimb lameness in horses

This study has investigated the immediate effect of induced hindlimb length difference on hindlimb lameness measured as differences in minimum (Pmin) and maximum (Pmax) pelvic heights in 16 horses trotting in a straight line and lungeing on both hard and soft surfaces with body-mounted inertial sensors. Hindlimb length differences were induced by applying an Easyboot Glue-on shoe to one hindlimb. Changes in Pmin and Pmax with induced hindlimb length difference were assessed with a two-way repeated-measures ANOVA with trial (straight, lunge with inside limb elevation, lunge with outside limb elevation) and surface (hard, soft) as within-subject factors. Change in Pmin, indicating an impact-type lameness, in the hind limb with the elevation, was significant in both the straight line and while lunging on both hard and soft surfaces. Change in Pmax, indicating pushoff-type lameness, in the opposite, non-elevated hind limb, was significant when trotting in a straight line but not while lunging.

Repeatability of subjective evaluation of lameness in horses

REASONS FOR PERFORMING STUDY

Previous studies have suggested that agreement between equine veterinarians subjectively evaluating lameness in horses is low. These studies were limited to small numbers of horses, evaluating movement on the treadmill or to evaluating previously-recorded videotape.

OBJECTIVES

To estimate agreement between equine practitioners performing lameness evaluations in horses in the live, over ground setting.

METHODS

131 mature horses were evaluated for lameness by 2-5 clinicians (mean 3.2) with a weighted-average of 18.7 years of experience. Clinicians graded each limb using the AAEP lameness scale by first watching the horse trot in a straight line only and then after full lameness evaluation. Agreement was estimated by calculation of Fleiss' (kappa). Evaluators agreed if they picked the same limb as lame or not lame regardless of the severity of perceived lameness.

RESULTS

After only evaluating the horse trot in a straight line clinicians agreed whether a limb was lame or not 76.6% of the time (kappa= 0.44). After full lameness evaluation clinicians agreed whether a limb was lame or not 72.9% of the time (kappa= 0.45). Agreement on forelimb lameness was slightly higher than on hindlimb lameness. When the mean AAEP lameness score was >1.5 clinicians agreed whether or not a limb was lame 93.1% of the time (kappa= 0.86), but when the mean score was < or = 1.5 they agreed 61.9% (kappa= 0.23) of the time. When given the task of picking whether or not the horse was lame and picking the worst limb after full lameness evaluation, clinicians agreed 51.6% (kappa= 0.37) of the time.

CONCLUSIONS

For horses with mild lameness subjective evaluation of lameness is not very reliable.

POTENTIAL RELEVANCE

A search for and the development of more objective and reliable methods of lameness evaluation is justified and should be encouraged and supported.

Inhibition of lysophosphatidic acid-induced neurite retraction and cell rounding by SR 57746A

Rapid neurite retraction and transient rounding of serum-starved NG108-15 and PC12 cells by lysophosphatidic acid (LPA) is retarded and reduced by pre-incubation of the cells with the small non-peptidic molecule, SR 57746A, which exhibits neurotrophic properties. The compound also antagonizes the redistribution of filamentous actin by LPA in both cell types. We hypothesize that the SR 57746A attenuation of LPA-induced effects may account for at least some of the neuroprotective properties of this molecule.

Evidence for nerve growth factor-potentiating activities of the nonpeptidic compound SR 57746A in PC12 cells

SR 57746A (1-[2-(naphth-2-yl)ethyl]-4-(3-trifluoromethylphenyl)-1,2,5,6- tetrahydropyridine hydrochloride) exhibits neurotrophic activities in vivo and in vitro. We used the rat pheochromocytoma PC12 cell line to investigate in vitro cellular changes induced by SR 57746A. A significant increase in the percentage of cells bearing neurite-like processes was obtained in cells treated by SR 57746A and nerve growth factor (NGF) compared with NGF treatment alone. SR 57746A added alone, however, had no effect on morphogenesis or on survival of cells in serum-free medium. In contrast, SR 57746A induced a "priming" effect on PC12 cells for neurite outgrowth within 6 h of addition of the protein tyrosine kinase inhibitor genistein. An increase in alpha-actinin content resulted from treatment with SR 57746A. Expression of NGF-mediated acetylcholinesterase and choline acetyltransferase was enhanced within 5 days by SR 57746A. The molecule also induced rapid F-actin redistribution. Within 2 min of incubation, outgrowth of F-actin-containing filopodia was clearly visible at the cell periphery, as previously shown with NGF. It is interesting that this effect of SR 57746A could be mimicked by protein tyrosine kinase inhibitors and abolished by preincubation with sodium orthovanadate, a protein tyrosine phosphatase inhibitor.

Transforming growth factor-beta 1 mRNA in neonatal ovine molars visualized by in situ hybridization: potential role for the stratum intermedium

Human dentine contains relatively large amounts of transforming growth factor-beta (TGF-beta), which might originate from odontoblasts. The expression of the TGF-beta 1 message in developing teeth was examined by in situ hybridization. The analysis was made on 5-microns serial sections of mandibular third molars of neonatal sheep cut from tissues that had been fixed in glutaraldehyde and paraffin-embedded. A 35S-labelled cRNA probe, complementary to TGF-beta 1 mRNA, was constructed from human TGF-beta 1 cDNA. Northern analysis of total RNA from sheep placenta and neonatal third molars demonstrated hybridization to a single 2.4 kb TGF-beta 1 transcript from both tissues, indicating cross-reactivity of the human probe in the sheep. In the neonatal molars, in situ hybridization was observed in cells of the inner enamel epithelium, mature ameloblasts and mature odontoblasts, but not within preodontoblasts before dentine matrix formation. TGF-beta 1 mRNA expression was also evident in the cells of the dental papilla but scarcely so in the stellate reticulum. The most striking feature was the appearance of hybridization signal in the cells of the stratum intermedium before hybridization was evident in the inner enamel epithelium. Control sections incubated with RNAase before incubation with probe did not show evidence of hybridization. These findings suggest that TGF-beta 1 may have an important regulatory role in the differentiation of ameloblasts and odontoblasts, perhaps by modulating matrix formation during amelogenesis or odontogenesis. They also suggest a potential novel regulatory role for the cells of the stratum intermedium.