The aim of this research was to evaluate the changes in the response of pattern-stimulated visual evoked potential (pVEP) with different pattern size, and demonstrate visual acuity from the minimum visual angle. pVEP was recorded from both eyes of six healthy beagles. Prior to pVEP recording, the dogs were sedated, and a traction fiber was used to prevent the eye from rolling down. The stimulator was set 30 cm from the subject's eye. Pattern reversal frequency of the stimulating monitor was 3 rev/sec, and pattern size was set at seven levels; 14-364 arc-min (1.2-31.4 mm). Amplitude of the P100 component was evaluated, and visual acuity was calculated from the minimum visual angle to obtain a pVEP response. A pVEP response (2.3-3.1 μV) was obtained from all subjects. The P100 component was detectable in 3 eyes with a check size of 14 arc-min and 7 eyes with 28 arc-min, and the component was undetectable with 14 arc-min in all subjects in which it was undetectable with 28 arc-min. From the minimum level to obtain the P100 component, the subjects' visual acuity was extrapolated as 0.54-2.14 cycles per degree. We demonstrated the change in P100 component with check size. However, our technique was inadequate to examine visual acuity because the subject's refractive index was ignored. We suggest that, with further study, pVEP with different check sizes would be applicable for canine visual acuity examination.

This study compared the effects of postoperative pain and inflammation reaction after preventive laparoscopic-assisted gastropexy (LAG) and incisional gastropexy (IG) in 10 clinically normal Beagles. Surgical time, incision length, visual analog scale (VAS) score, University of Melbourne Pain Scale (UMPS) score, and plasma C-reactive protein (CRP), plasma cortisol (COR), and serum interleukin-6 (IL-6) levels were evaluated. The VAS and UMPS scores and COR and IL-6 levels were recorded at 0.5, 1, 2, 4, 8, 12, 18 and 24 hr after surgery. CRP level was recorded at 12, 24 and 48 hr after surgery. The VAS and UMPS scores showed no significant intergroup differences. Compared to IG, LAG had significantly lower surgical time (45 ± 9.91 min vs 64 ± 5.30 min; P<0.05), incision length (46 ± 8.21 mm vs 129 ± 19.49 mm; P<0.05), CRP level (12 hr after surgery; 4.58 ± 1.58 mg/dl vs 12.4 ± 1.34 mg/dl; P<0.01), and COR level (1 hr after surgery; 10.79 ± 3.07 µg/dl vs 15.9 ± 3.77 µg/dl; P<0.05). IL-6 levels showed no significant intergroup differences at any time point. However, LAG resulted in lower IL-6 levels than did IG at all postoperative time points. Neither procedure resulted in significant surgical complications. LAG produced lower surgical stress than did IG, suggesting that LAG is a safe, minimally invasive, and highly useful technique for preventing canine gastric dilatation-volvulus. Nevertheless, since this study used experimental models, its usefulness should be evaluated in future cases.

Electroretinography (ERG) is an effective method for the diagnosis of retinal disease. In the dog, dependable ERG recording is difficult without the use of an expensive device like a Ganzfeld full-field stimulator. The International Society for Clinical Electrophysiology of Vision has defined the standard flash stimulus condition (SF) and evaluation of the retina using the b/a ratio in humans. In dogs, evaluation using the b/a ratio has not been reported, whereas the intensity of SF has been defined. In this study, we performed a convenient ERG recording method using a contact lens electrode with a built-in light source (LED-electrode), and confirmed SF as reported previously. ERG recordings were performed on 15 healthy beagle dogs under sedation. We performed bilateral ERG at 12 different intensities after 30 min dark adaptation. After 10 min light adaptation, we recorded single flash cone and flicker cone response using the SF determined in this study. In this study, SF of 3.0 cd/m2/sec (6,000 cd/m2, 0.5 msec) resulted in b/a=2. The intensity for rod response that recorded only the b-wave was 0.0096 cd/m2/sec (80 cd/m2, 0.12 msec). We could achieve ERG for each response easily and smoothly under sedation, and without general anesthesia. Using an LED-electrode, we could perform more quantitative and reproducible ERG examinations than with traditional methods. We propose that the b/a ratio is the most useful parameter in ERG reporting for evaluating retinal function.