Tissue predictability of elastography is low in collagenase induced deep digital flexor tendinopathy.

Elastography is an emerging imaging modality for characterizing tendon injury in horses, but its ability to differentiate tissue deformability relative to treatment group and biochemical properties using a prospective, experimental study design remain unknown. Objectives of the current study were to (a) to investigate differences in glycosaminoglycan, DNA, and soluble collagen levels in mesenchymal stem cell (MSC) treated limbs compared to untreated control limbs utilizing a collagenase model of tendinopathy; (b) compare elastographic features between treatment groups; and (c) determine tissue-level predictive capabilities of elastography in relation to biochemical outcomes. Bone marrow was collected for MSC culture and expansion. Tendinopathy of both forelimb deep digital flexor tendons (DDFTs) was induced with collagenase under ultrasonographic guidance. One randomly assigned limb was treated with intra-lesional MSC injection with the opposite limb serving as an untreated control. Horses were placed into a controlled exercise program with elastographic evaluations performed baseline (0) and 14, 60, 90, and 214 days post-treatment. Postmortem biochemical analysis was performed. MSC-treated limbs demonstrated significantly less (42%) glycosaminoglycan (P = .006). Significant differences in elastographic region of interest (ROI) percent hardness, ROI color histogram, and subjective lesion stiffness were appreciated between treatment groups at various study time points. Elastographic outcome parameters were weak predictors of biochemical tissue analysis, with all R2 values ≤ 0.50. Within this range of differences in glycosaminoglycan content between treatment groups, elastography outcomes did not predict biochemical differences. Tissue-specific differences between DDFTs treated with MSCs compared to controls were apparent biochemically, but not predicted by elastography.

Clinical features and outcome in horses with severe large intestinal thickening diagnosed with transabdominal ultrasonography: 25 cases (2003-2010).

OBJECTIVE To describe clinical features and outcome of horses with severe large intestinal thickening diagnosed with transabdominal ultrasonography. DESIGN: Retrospective case series. ANIMALS 25 horses. PROCEDURES Medical records of horses that underwent transabdominal ultrasonography between 2003 and 2010 were reviewed. Horses were included if the wall of the large intestine was ≥ 9 mm thick in any of 6 abdominal zones. RESULTS Median age was 13 years (range, 3 to 28 years). Horses were initially examined because of colic, diarrhea, inappetence, weight loss, lethargy, fever, or hematuria. Severe large intestinal thickening (range, 9 to 46.6 mm; mean ± SD, 18.8 ± 6.8 mm) was the primary ultrasonographic finding in all horses. Thickened large intestine was more likely to be detected in ventral versus upper (ie, combined paralumbar and intercostal) abdominal zones and in right versus left zones. Eleven horses survived and had resolution of clinical signs, including the l horse treated surgically for colon torsion. An additional horse survived but continued to have intermittent colic. Ten horses were euthanized or died, including 3 horses with neoplasia and 3 with colitis. Three horses were lost to follow-up, including 1 horse with a cecal mass and 1 with hepatosplenic lymphoma. Severity of thickening and number of zones affected were not significantly different between survivors and nonsurvivors. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that in horses undergoing transabdominal ultrasonography, large intestinal wall thickness ≥ 9 mm may be detected in patients with a variety of conditions. Ultrasonographic examination of all abdominal zones was helpful to determine the extent of thickening and identify additional findings that helped prioritize differential diagnoses.

Ontogeny of circadian organization in the rat.

The mammalian circadian system is orchestrated by a master pacemaker in the brain, but many peripheral tissues also contain independent or quasi-independent circadian oscillators. The adaptive significance of clocks in these structures must lie, in large part, in the phase relationships between the constituent oscillators and their micro- and macroenvironments. To examine the relationship between postnatal development, which is dependent on endogenous programs and maternal/environmental influences, and the phase of circadian oscillators, the authors assessed the circadian phase of pineal, liver, lung, adrenal, and thyroid tissues cultured from Period 1-luciferase (Per1-luc ) rat pups of various postnatal ages. The liver, thyroid, and pineal were rhythmic at birth, but the phases of their Per1-luc expression rhythms shifted remarkably during development. To determine if the timing of the phase shift in each tissue could be the result of changing environmental conditions, the behavior of pups and their mothers was monitored. The circadian phase of the liver shifted from the day to night around postnatal day (P) 22 as the pups nursed less during the light and instead ate solid food during the dark. Furthermore, the phase of Per1-luc expression in liver cultures from nursing neonates could be shifted experimentally from the day to the night by allowing pups access to the dam only during the dark. Peak Per1-luc expression also shifted from midday to early night in thyroid cultures at about P20, concurrent with the shift in eating times. The phase of Per1-luc expression in the pineal gland shifted from day to night coincident with its sympathetic innervation at around P5. Per1-luc expression was rhythmic in adrenal cultures and peaked around the time of lights-off throughout development; however, the amplitude of the rhythm increased at P25. Lung cultures were completely arrhythmic until P12 when the pups began to leave the nest. Taken together, the data suggest that the molecular machinery that generates circadian oscillations matures at different rates in different tissues and that the phase of at least some peripheral organs is malleable and may shift as the organ's function changes during development.