Background: Plasma a-melanocyte-stimulating hormone (a-MSH) and adrenocorticotropin (ACTH) concentrations in horses vary with season, confounding diagnostic testing for pituitary pars intermedia dysfunction (PPID).Hypothesis: The goals of this study were to determine whether seasonal variation in plasma a-MSH and ACTH concentrations in horses is influenced by geographic location, breed, or PPID.Animals: Healthy light breed horses residing in Florida, Massachusetts, and Finland (n 5 12 per group); healthy Morgan horses (n 5 13); healthy ponies (n 5 9) and horses with PPID (n 5 8).Methods: Monthly plasma a-MSH and ACTH concentrations were measured by radioimmunoassay. Nonlinear regression analysis was used to estimate the time of peak hormone concentrations. Mean hormone concentrations in fall and nonfall months were compared.Results: The fall peak plasma a-MSH concentration occurred earlier in horses residing at more northern locations. Mean seasonal a-MSH concentrations were similar in all healthy groups at all locations, but in the fall, plasma ACTH concentrations were higher in horses living in more southern locations. Plasma ACTH but not a-MSH concentrations were higher in Morgan horses compared with light breed horses from the same location. Hormone concentrations of ponies did not differ from those of horses during either season. Concentrations of both hormones were high in the fall compared with the spring in horses with PPID.Conclusions and Clinical Importance: These findings suggest geographic location of residence and breed may affect the onset, amplitude, or both of the seasonal peak of pars intermedia (PI) hormones and should be considered when performing diagnostic testing for PPID. Horses with PPID maintain seasonal regulation of PI hormone output.

Background:We have previously shown that the non-selective cyclooxygenase (COX) inhibitor indomethacin retards recovery of intestinal barrier function in ischaemic injured porcine ileum. However, the relative role of COX-1 and COX-2 elaborated prostaglandins in this process is unclear. Aims: To assess the role of COX-1 and COX-2 elaborated prostaglandins in the recovery of intestinal barrier function by evaluating the effects of selective COX-1 and COX-2 inhibitors on mucosal recovery and eicosanoid production. Methods: Porcine ileal mucosa subjected to 45 minutes of ischaemia was mounted in Ussing chambers, and transepithelial electrical resistance was used as an indicator of mucosal recovery. Prostaglandins E 1 and E 2 (PGE) and 6-keto-PGF 1α (the stable metabolite of prostaglandin I 2 (PGI 2 )) were measured using ELISA. Thromboxane B 2 (TXB 2 , the stable metabolite of TXA 2 ) was measured as a likely indicator of COX-1 activity. Results: Ischaemic injured tissues recovered to control levels of resistance within three hours whereas tissues treated with indomethacin (5×10 Μ) recovered to control levels of resistance within three hours, associated with significant elevations of PGE and 6-keto-PGF 1α compared with untreated tissues. However, SC-560 significantly inhibited TXB 2 production whereas NS-398 had no effect on this eicosanoid, indicating differential actions of these inhibitors related to their COX selectivity. Conclusions:The results suggest that recovery of resistance is triggered by PGE and PGI 2 , which may be elaborated by either COX

Results revealed significant associations between a diagnosis of fragments of the proximal phalanx, presale arthroscopy, and sales price in Thoroughbred yearlings.

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Background: Hepatic failure is one of the more common complications in foals requiring blood transfusion to treat neonatal isoerythrolysis. Iron intoxication is likely the cause of hepatic injury.Objectives: To determine the effects of deferoxamine on iron elimination in normal foals. Animals: Thirteen neonatal foals. Methods: Randomized-controlled trial. At 1-3 days of age, foals received either 3 L of washed packed dam's red blood cells (RBC) or 3 L of saline IV once. Foals were treated with deferoxamine (1 g) or saline (5 mL) SC twice daily for 14 days. Foals were randomly assigned to 1 of 3 groups: RBC/deferoxamine (deferoxamine), RBC/saline (placebo), or saline/saline (control). Blood and urine samples and liver biopsy specimens were collected for measurement of hematological, biochemical, and iron metabolism variables.Results: There was a significant (P o .05) increase in hematocrit, RBC count, and hemoglobin in the groups transfused with packed RBC as compared with controls at all times. Biochemical variables and liver biopsy scores were not significantly different between groups at any time. Urine iron concentrations and fractional excretion of iron were significantly higher in deferoxamine treated foals. By 14 days after transfusion, liver iron concentrations in foals treated with deferoxamine (79.9 AE 30.9 ppm) were significantly lower than that of foals receiving placebo (145 AE 53.0 ppm) and similar to that of controls (44.8 AE 4.09 ppm).Conclusions and Clinical Importance: Deferoxamine enhances urinary iron elimination and decreases hepatic iron accumulation after blood transfusion in foals.