Clinical Effects of Longitudinal Division of the Corpus Callosum in Normal Dogs

Longitudinal division of the corpus callosum was performed in six normal beagles to determine surgical morbidity. The corpus callosum was divided sagittally on the midline and the effect on neurological function was determined. Five of six dogs were clinically normal within 14 days or less after surgery. One dog had persistent but improving clinical signs consistent with a forebrain disturbance at 30 days after surgery. Overall, minimal morbidity and no mortality was associated with this surgical procedure. Further study is indicated to determine the efficacy of this surgical treatment for seizure control in dogs with idiopathic epilepsy.     

Radiosensitivity and capacity for radiation-induced sublethal damage repair of canine transitional cell carcinoma (TCC) cell lines

Understanding the inherent radiosensitivity and repair capacity of canine transitional cell carcinoma (TCC) can aid in optimizing radiation protocols to treat this disease. The objective of this study was to evaluate the parameters surviving fraction at 2 Gy (SF(2) ), α/β ratio and capacity for sublethal damage repair (SLDR) in response to radiation. Dose-response and split-dose studies were performed using the clonogenic assay. The mean SF(2) for three established TCC cell lines was high at 0.61. All the three cell lines exhibited a low to moderate α/β ratio, with the mean being 3.27. Two cell lines exhibited statistically increased survival at 4 and 24 h in the dose-response assay. Overall, our results indicate that the cell lines are moderately radioresistant, have a high repair capacity and behave similarly to a late-responding normal tissue. These findings indicate that the radiation protocols utilizing higher doses with less fractionation may be more effective for treating TCC.     

The effect of sulfaphenazole and sulfadoxine on tolbutamide disposition in dwarf goats (Caprus hircus aegagrus)

The aim of the present study was to investigate the effects of intravenously administered sulfadoxine (5 mg kg ⁻¹ bodyweight) or sulfaphenazole (5 mg kg⁻¹ bodyweight) on the in vivo elimination of i.v. tolbutamide (5 mg kg⁻¹ bodyweight), as both compounds were shown to inhibit tolbutamide hydroxylation in vitro. It was shown that relative large differences in tolbutamide clearance exist among goats (n = 6). A high correlation was seen between tolbutamide and sulfadoxine clearances. Tolbutamide clearance was significantly reduced by concommitant administration of sulfaphenazole. Sulfadoxine ( ) had a less consistent effect. Mean tolbutamide plasma clearance was not significantly affected due to the fact that three animals showed an inhibition, whereas three others apparently did not respond. A negative correlation was found between the amount of N4-acetyl in urine and the clearance. Approximately 93 per cent of tolbutamide was bound to plasma proteins. However, there was no evidence for displacement of tolbutamide from its protein binding sites by sulfaphenazole or sulfadoxine. The results described in the present study confirm previous in vitro data obtained with goat hepatocytes. Although quantitative differences in inhibition exist between in vivo and in vitro results, hepatocytes are a good model to study potential drug-drug interactions at the level of biotransformation processes.     

Cardiac glycoside poisoning in sheep caused by Urginea physodes (Jacq.) Bak. and the isolated physodine A

Urginea physodes (Jacq.) Bak., a species closely related to or possibly synonymous with U. pusilla, is described and its distribution given. Four bufadienolides were isolated from U. physodes and the approximated LD50 and cumulative effect of some of them determined in guinea pigs. The most toxic one proved to be mildly cumulative. Typical signs of acute cardiac glycoside poisoning, involving the locomotory, gastro-intestinal, respiratory and cardiac system, were seen in the field cases and/or were experimentally induced by the plant. Similar signs could also be induced by injecting the isolated bufadienolide, physodine A, to a sheep.     

Surgical Management of Proximal Splint Bone Fractures in the Horse

Fractures of Metacarpal and Metatarsal II and IV (the splint bones) were treated in 283 horses over an 11 year period. In 21 cases the proximal portion of the fractured bone was stabilized with metallic implants. One or more cortical bone screws were used in 11 horses, and bone plates were applied in 11 horses. One horse received both treatments. Complications of screw fixation included bone failure, implant failure, radiographic lucency around the screws, and proliferative new bone at the ostectomy site. Only two of the horses treated with screw fixation returned to their intended use. Complications of plate fixation included partial fixation failure (backing out of screws), wound drainage, and proliferative bony response around the plate. Six of the 11 horses treated by plate fixation returned to their intended use. The authors recommend consideration of plate fixation techniques for repair of fractures in the proximal third of the splint bone.     

Techniques for venous blood sampling from the white pekin duck

Common sites for blood sampling in the pekin duck and other avian species include the basilic vein, jugular vein, superficial plantar metatarsal vein, heart, and occipital sinus. The use of each of these sites is described and/or illustrated. In the present study using the pekin duck, the superficial plantar metatarsal vein proved most satisfactory for collecting repeated samples (every 5 minutes for 30 minutes) with minimal trauma to the duck.     

Comparison of the effects of etomidate and its fluoro analogue, R 8110, on plasma Cortisol, 11β-deoxycortisol, 17α-hydroxyprogesterone and testosterone concentrations in dogs

R 8110, an imidazole derivative, was shown to be clinically superior to etomidate for induction and maintenance of anaesthesia in dogs. The present study compared the effects of intravenous (i.v.) R 8110, etomidate and Ringer solution on cortisol biosynthesis by the adrenal gland in seven male labradors. A tetracosactide challenge was carried out 30 min after the i.v. injection of 3 mg/kg of both drugs and after i.v. Ringer solution (1 ml/kg). Etomidate and R 8110 both suppressed the cortisol response to tetracosactide almost completely and increased the plasma 11 beta-deoxycortisol levels more than 20 fold. Maximal 11 beta-deoxycortisol values were reached 120 min after R 8110, and not less than 300 min after etomidate. Plasma 17 alpha-hydroxyprogesterone and testosterone concentrations did not differ between placebo and R 8110 treatment, but they decreased after etomidate. These results indicate that the effects of R 8110 on steroid biosynthesis in dogs are less pronounced than those of etomidate and are largely limited to a temporary inhibition of the 11 beta-hydroxylase in the adrenal gland.     

MAGNETIC RESONANCE IMAGING OF THE NORMAL EQUINE DIGIT AND METACARPOPHALANGEAL JOINT

Magnetic resonance (MR) images were made in sagittal and transverse planes through the metacarpophalangeal joint and digit of a horse. The images accurately depicted gross anatomic structures in the leg. Soft tissue structures were defined as separate entities on the images. Histologic varlation in tissues correlated with signal intensity differences on the MR images. Magnetic resonance imaging appears to be a promising imaging modality for evaluating musculoskeletal structures in equine limbs.