To establish the protocol of a standardized exercise test for evaluating exercise intolerance and degree of fitness in Thoroughbred racehorses, we examined serum lactate concentrations related to exercise intensities using the high speed tradmill. Twelve clinically healthy Thoroughbred racehorses with or without previous training or racing history were assigned to two groups, fit and unfit group, respectively. The protocol used for the standardized exercise test was consisted of two stages:stage ofwarm-up and that of acceleration. During the warm-up, the horses exercised 5 min at 1.8m/s and 3 min 3.4m/s without inclination. At the acceleration stage, exercise test was performed at 10% slope and the speed was increased from the initial 5m/s to the maximal speed which each tested horse could keep up with. The speed was increased with incremental steps of 1 m/s every minute. During the last 15 sec of each step, blood samples were collected for serum lactate determination. V max (masimal treadmill speed which tested horses could keep up with) of the fit group (10.93+_0.33m/s, mean+_SE, n=6) was higher than that of the unfit group (9.52+_0.23m/s, mean+_SE, n=6). Serum lactate concentrations increased exponentially according to exercise intensities. V la4 (speed producing a serum lactate concentration of 4mmol/l) of the fit group, 6.45+_0.26m/s, was higher than that of the unfit group, 5.45+_0.23m/s. La peak (peak plasma lactate concentration during the exercise test) was lower in the fit group (20.34+_1.62mmol/l at 1 min after maximal intensity exercise) than in the unfit group (24.78+_1.09mmol/l at 2 min after maximal exercise step). t50% (time required for the recovery of lactate concentration to be one-half of La peak after maximal exercise) of the unfit group and the fit group were 40.0 and 18.0 min, respectively. Therefore, the protocol of the incremental standardized exercise test utilized in this study seems to be reliable for the assessment of fitness and exercise intolerance for the Thoroughbred racehorses.

Linear and non-linear regressions were used to derive the calibration function for the measurement of roxithromycin plasma concentration. Their results were compared with weighted least squares regression by usual weight factors. In this paper the performance of a non-linear calibration equation with the capacity to account empirically for the curvature, y = ax∨b + c (b not equal to 1) is compared with the commonly used linear equation, y = ax + b, as well as the quadratic equation, y = ax²+ bx + c. In the calibration curve (range of 0.01 to 10 ㎍/mL) of roxithromycin, both heteroscedasticity and nonlinearity were present therefore linear least squares regression methods could result in large errors in the determination of roxithromycin concentration. By the non-linear and weighted least squares regression, the accuracy of the analytical method was improved at the lower end of the calibration curve. This study suggests that the non-linear calibration equation should be considered when a curve is required to be fitted to low dose calibration data which exhibit slight curvature.

Currently the diagnosis of renal diseases is based on thorough history, clinical examination, urinanalysis and investigation of hemato-biochemical profiles. But biochemical markers are not sensitive to detect early renal damage. Also usefulness of their estimation is limited in early renal failure when marked reduction of GFR may be associated with little change in their concentration. At present imaging is an important diagnostic tool for early precise diagnosis. Scintigraphy is a less known diagnostic imaging technique in veterinary medicine, although it is similar to competitive methods such as radiography, ultrasound and endoscopy. By all the other methods only morphological objects can be visualized whereas scintigraphy has the advantage of the so-called physiological imaging. Scintigraphy is able to visualize and quantitate distribution of different materials in living organisms indicating normal [physiological] or abnormal (pathological) processes of the object. This is a sensitive, specific and non-invasive diagnostic method supporting clinician's diagnosis, as a part of combined modality-imaging systems; it gives useful data for veterinary clinicians. Present study was planned to standardize the scintigraphic profile for healthy dogs. Perfusion index Mean ± S.D. for right kidneys and left kidney was 154.7 ± 40.05 and 169.0 ± 46.0. The mean percent uptake at 2-3 minutes was 53.56 ± 6.17 and 46.46 ± 6.17 for right and left kidney. Time taken to Peak (TPP) minute, which indicates efficiency of blood flow at both the kidneys, was 3.12 ± 1.21 and 3.03 ± 1.22 min for right and left kidney respectively. The T½ from peak count [min] for right and left kidney was 5.02 ± 2.24 and 5.15 ± 3.6 min. The GFR for right and left kidneys was 68.79 ± 33.67 and 61.62 ± 31.92, respectively and the normalized GFR when both the kidneys are considered together in healthy dogs was 439.48 ± 55.67.