Insulin-Like Growth Factor-1 and Selected Insulin-Like Growth Factor Binding Protein Concentrations during an Ultramarathon Sled Dog Race.

The objective of this study was to investigate the effects of running a 1000-mile (1600 km) endurance sled dog race on serum insulin-like growth factor-1 (IGF-1) and insulin-like growth factor binding proteins 1 and 3 (IGFBP-1 and IGFBP-3). Serum was examined from 12 sled dogs prior to the race, at midrace (approximately 690 km), and again at the finish. IGF-1, IGFBP-1, and IGFBP-3 were assessed using radioimmunoassay or enzyme linked immune-absorbance assays. Mean prerace concentrations were significantly higher than midrace and end-race concentrations at 215.93 ± 80.51 ng/mL, 54.29 ± 25.45 ng/mL, and 55.53 ± 28.25 ng/mL, respectively (P < 0.001). Mean IGFBP-1 concentrations were not different across these time periods at 24.1 ± 15.8 ng/mL, 25.7 ± 14.0 ng/mL, and 26.6 ± 17.6 ng/mL, respectively. IGFBP-3 concentrations showed a modest significant decrease across time periods at 3,067 ± 2,792 ng/mL, 2,626 ± 2,310 ng/mL, and 2,331 ± 2,301 ng/mL, respectively (P < 0.01). Endurance sled dogs show a precipitous drop in serum IGF-1 concentrations. These differences may be related to fuel utilization and excessive negative energy balance associated with the loss of body condition during racing. The relative stability of IGFBP-1 and IGFBP-3 suggests that IGF-1 anabolic signaling is diminished during ultramarathon racing. Further studies comparing the influence of time and duration of exercise versus negative energy balance on serum IGF-1 status are warranted to better understand exercise versus negative energy balance differences.

Ground reaction forces, temporospatial parameters, range of motion, and limb characteristics were analyzed for small and medium size sound dogs with the use of pressure sensitive walkway.

OBJECTIVE: To study ground reaction forces (GRF) and temporospatial parameters for small and medium size dogs using a pressure sensitive walkway (PSW). We hypothesized that, at a given speed, small dogs would have shorter stance time than medium dogs and that dog height (DH) would influence GRF. ANIMALS: 30 healthy, sound dogs were divided into 2 groups, small < 15 kg and medium dog group weighing 15 to 25 kg. PROCEDURES: GRFs were measured for both groups at walk and trot using PSW. Muscle mass and joint angles were measured. Data were analyzed using SAS version 9.4. Two groups were compared using 2-sample t test, Wilcoxon rank sum test, and Fisher exact test. RESULTS: GRFs were successfully measured in both dog groups for walk and trot. Medium dogs had larger limb girth, more peak pressure, max force, increased stance, swing time, and larger stride length compared with small dogs. Stance time increased as DH increased at walk and trot (r = 0.854, P < .001; r = 0.876, P < .001). Stance time increased as BW (body weight) increased at walk and trot (r = 0.887, P < .001; r = 0.858 P < .001). Inconclusive data was obtained for stride acceleration and velocity. The handler side did not influence results (P > .05). Range of motion (ROM) did not differ among groups. CLINICAL RELEVANCE: Results suggested that PSW is a reliable device for small and medium dogs. At walk and at a trot, GRF are smaller in small dogs compared with medium dogs, suggesting that normal reference data for PSW need to take BW and DH into account.

Lower centrifugation speed and time are positively associated with platelet concentration in a canine autologous conditioned plasma system.

OBJECTIVE: To evaluate the effect of variable centrifugation protocols on the cellular composition of the final product of a canine autologous conditioned plasma double-syringe system. ANIMALS: 30 client-owned healthy adult medium- to large-breed (17- to 45-kg) dogs. METHODS: 35 mL of anticoagulated whole blood from each subject was aliquoted into 3 samples: a baseline and 2 double syringes. The syringes were processed for platelet-rich plasma (PRP). Each double syringe was randomly assigned to 1 of 5 groups, which varied in centrifugation settings between 580 and 1,304 X g and 5 and 10 minutes. CBC analysis was performed on each of the samples to determine cellular composition. A mixed-effect linear model was fit to the data. RESULTS: 60 PRP samples and 30 whole blood samples were analyzed. Manufacturer settings generated a platelet fold change > 1 but did not increase concentration to the extent expected. When comparing speed alone, increased centrifugation force was associated with lower platelet fold change. When comparing time alone, increased centrifugation time was also associated with lower platelet fold change and lower leukocyte concentration. CLINICAL RELEVANCE: Autologous conditioned plasma double syringes require a low volume of initial whole blood, making them preferable for canine PRP in clinical settings. This study aimed to evaluate the effect of the centrifugation protocol on the final product cellular composition in dogs and add to the available data on protocols to maximize platelet yield in PRP. Due to inherent individual variability, this study emphasized the importance of evaluating biological samples prior to administration to predict and improve patient outcomes.