Phenylbutazone in racing Greyhounds: plasma and urinary residues 24 and 48 hours after a single intravenous administration

SUMMARY The concentrations of phenylbutazone (PBZ), oxyphenbutazone (OPBZ) and gammahydroxyphenylbutazone (OHPBZ) in plasma and urine from 50 Greyhounds 24 and 48 h after the intravenous administration of a single dose of PBZ (30 mg/kg) were measured. The 24 h plasma concentrations of OPBZ and OHPBZ, the 48 h plasma concentration of OHPBZ and the 24 h urinary concentration of PBZ were normally distributed, while log transformations were required before the 24 h plasma concentration of PBZ and the 24 and 48 h urinary concentrations of OPBZ and OHPBZ became normally distributed. The 95%, 99%, 99.9% and 99.99% upper predicted confidence intervals for both 24 h and 48 h plasma and urinary concentrations demonstrated wide potential variation in the concentration of the analytes should PBZ be administered to Greyhounds. The 24 h plasma and urinary concentrations of PBZ were weakly correlated, but no similar relationship existed for OPBZ or OHPBZ. The urinary concentrations of each analyte were not affected by the trainer or sex of the Greyhound or the urinary pH. We conclude that it would be impossible to predict the timing of the PBZ administration or the plasma concentration of PBZ from the measurement of the concentration of PBZ in a single sample of urine.     

Morphometry and abnormalities of the feet of Kaimanawa feral horses in New Zealand

Objective The present study investigated the foot health of the Kaimanawa feral horse population and tested the hypotheses that horses would have a large range of foot morphology and that the incidence of foot abnormality would be significantly high. Procedures Abnormality was defined as a variation from what the two veterinarian assessors considered as optimal morphology and which was considered to impact negatively on the structure and/or function of the foot. Fifteen morphometric variables were measured on four calibrated photographic views of all four feet of 20 adult Kaimanawa feral horses. Four morphometric variables were measured from the lateromedial radiographs of the left forefoot of each horse. In addition, the study identified the incidence of gross abnormality observed on the photographs and radiographs of all 80 feet. Results There was a large variation between horses in the morphometric dimensions, indicating an inconsistent foot type. Mean hoof variables were outside the normal range recommended by veterinarians and hoof care providers; 35% of all feet had a long toe conformation and 15% had a mediolateral imbalance. Abnormalities included lateral (85% of horses) and dorsal (90% of horses) wall flares, presence of laminar rings (80% of horses) and bull-nose tip of the distal phalanx (75% of horses). Both hypotheses were therefore accepted. Conclusions The Kaimanawa feral horse population demonstrated a broad range of foot abnormalities and we propose that one reason for the questionable foot health and conformation is lack of abrasive wearing by the environment. In comparison with other feral horse populations in Australia and America there may be less pressure on the natural selection of the foot of the Kaimanawa horses by the forgiving environment of the Kaimanawa Ranges. Contrary to popular belief, the feral horse foot type should not be used as an ideal model for the domestic horse foot.     

Composition Dependencies of the Rheological Properties of Rice Starch Blends

The gelatinization, pasting, and dynamic rheological parameters of rice starch dispersions from Kaoshiung Sen 7 (KSS7), Taichung Waxy 70 (TCW70), and their blends were examined in relation to total starch concentration (C_t) and the property of starch components. Mixing the rice starches, especially at equivalent ratios, resulted in decreasing onset temperature for gelatinization or developing viscosity and in cold‐paste viscosity, accompanied by a synergistically increased peak viscosity. The logarithmic of storage moduli, G′, for all starch dispersions except the retrograded systems of C_t = 20–30 wt%, showed two linear dependencies on the weight‐average amylose content (AC) of the blends separating at a critical AC of 20 wt% (i.e., TCW70 = 25 wt%). Interestingly, the temperatures at which G′ started to increase drastically maximized on heating, and the exponent n of G′ ∝ C_tⁿ also maximized at the same TCW70 starch concentration Generally, the elasticity of the systems after complete gelatinization and retrogradation followed the isostress models of Takayanagi's blending laws at C_t = 10 wt%, but changed to the intermediates of isostress and isostrain at C_t = 20–30 wt%. The changes in these parameters can be explained by competitive swelling behavior, the strengthening effect of swollen granules, and shear disintegration.     

Retinal photoreceptor damage produced in guinea pigs by tunicamycin

Corynetoxins, members of the tunicamycin group of antibiotics, produce a severe and frequently fatal neurological disorder in ruminant livestock, and guinea pigs are a useful model to study the pathology and pathogenesis of this disease. The aim of this study was to determine whether tunicamycin produced ocular damage in this species, which could have pharmacotherapeutic and diagnostic value. Four 8-week-old guinea pigs were treated with tunicamycin, and two control animals were given the drug vehicle only. Guinea pigs were injected subcutaneously with 400 μg/kg of tunicamycin, in dimethyl sulphoxide, and killed 48 h post-injection. The eyes were then examined by light microscopy. Immunohistochemistry for rhodopsin was also performed. The principal pathological finding was marked retinal photoreceptor damage, which was characterised by disruption and disorganisation of rods, sometimes progressing to necrosis and separation of the outer segment. The cytoplasm of some rods was focally distended by accumulated, proteinaceous material. Rhodopsin immunopositivity in injured rods was markedly diminished and associated with shrinkage and shortening of the injured rod's outer segment. Ocular pathology, in the form of reproducible and extensive retinal photoreceptor damage, was found in guinea pigs given tunicamycin, extending the range of species found to be susceptible to this toxic injury. The guinea pig could prove to be a good animal model to test potential therapeutic interventions, and as brain lesions are often minimal and liver pathology non-specific in intoxicated ruminants, any spontaneously arising ophthalmic injury found in these species could be diagnostically useful.     

Hydatidosis in a Chapman's zebra (Equus burchelli antiquorum).

A 14-year-old male Chapman's zebra had been treated for a cervical granulomatous cellulitis for 3 months prior to sudden death associated with myocardial fibrosis. Incidental findings at necropsy included multiple 3-8-cm unilocular cysts in the liver and lungs. Cysts contained either a clear fluid with or without hydatid sand or a gelatinous substance with foci of mineralization. Light and scanning electron microscopic examination of the hydatid sand revealed free protoscolices as well as intact and ruptured brood capsules with protoscolices attached to the germinal membrane. The protoscolices had 2 rows of 36-38 rostellar hooks with a length of 25-30 microm. The cyst wall consisted of inner germinal, intermediate laminated, and outer adventitial layers. Hydatidosis caused by Echinococcus granulosus was diagnosed based on the unilocular cysts, multiple protoscolices formed in a brood capsule, typical trilayered cyst wall, and herbivorous intermediate host. This is the first reported case of animal hydatidosis in Taiwan. The infection is thought to have been established 12 years ago in South Africa prior to importation.     

Alzheimer type II astrocytes in the brains of pigs with salt poisoning (water deprivation/intoxication)

The finding of Alzheimer type II astrocytes, in addition to the pathognomonic combination of laminar cerebrocortical necrosis and eosinophil infiltration, in the brains of pigs is reported for the first time in cases of indirect salt poisoning following water deprivation.