MAGNETIC RESONANCE IMAGING OF CEREBRAL CORTICAL NECROSIS (POLIOENCEPHALOMALACIA) IN A DOG

A 3-year-old neutered female mixed breed dog was examined because of severe, generalized seizure activity, tetraparesis, and encephalopathic signs. Cerebrospinal fluid (CSF) evaluation was unremarkable except for a mild increase in protein. Serum and CSF titers for infectious diseases were negative. Magnetic resonance (MR) imaging examination of the brain was performed and lesions were found within the cerebral gray matter of the temporal and parietal lobes. The lesions had increased signal intensity on T1, T2, and proton density-weighted images. There was mild inhomogeneous enhancement following intravenous contrast medium administration. Neurologic status improved and the seizures were well controlled, but the dog never regained normal mentation and euthanasia was performed 10 weeks after initial evaluation. At necropsy, severe cerebral cortical necrosis was found in the regions corresponding to the lesions seen on MR imaging examination. Large numbers of fat-containing macrophages (gitter cells) were found within these areas, and are thought to be responsible for the characteristic hyperintensity seen on the MR images.     

A DNA vaccine encoding MPB83 from Mycobacterium bovis reduces M. bovis dissemination to the kidneys of mice and is expressed in primary cell cultures of the European badger (Meles meles)

Nucleic acid (DNA) vaccination against tuberculosis in the European badger (Meles meles) is one approach to addressing the escalating problem of bovine tuberculosis in Great Britain. The aim of vaccination is to reduce the burden of tuberculosis within the badger population and the shedding of Mycobacterium bovis to levels that would break the transmission of infection to cattle. To this end, the vaccine would be required to limit the amount of disseminated tuberculosis in the badger, especially dissemination to the kidney from where M. bovis can be shed in the urine. A promising candidate DNA vaccine encoding a 26 kDa major antigen (MPB83) of M. bovis was evaluated in a mouse model of disseminated M. bovis infection. Using the DNA vaccine, protection against infection of the kidney was found to be greater than that achieved with the current live vaccine, Bacille Calmette-Guerin (BCG). Kidney tissue and skeletal muscle from the badger was used to derive primary cell cultures in which to examine the expression of MPB83 following transfection with the DNA vaccine. Kidney cortex gave rise to a monotypic culture of epithelial cells whilst the muscle gave rise to a mixed culture of fibroblasts and myoblasts. During culture the myoblasts differentiated into multinucleated myotubes, verified by immunofluorescent detection of mammalian desmin. Successful expression of MPB83 by transfected epithelial and myotube cells was confirmed by immunofluorescence using a monoclonal antibody specific to the protein. These observations fulfil the early requirements for the development of a DNA vaccine for badger tuberculosis.     

Effects of the calcium channel antagonist amlodipine in cats with surgically induced hypertensive renal insufficiency

OBJECTIVE: To determine whether amlodipine besylate decreases systemic arterial blood pressure (BP) and reduces the prevalence of complications in cats with induced hypertensive renal insufficiency. ANIMALS: 20 cats with partial nephrectomy. PROCEDURE: Following reduction in renal mass, 10 cats were administered 0.25 mg of amlodipine/kg, PO, q 24 h (group A). Ten cats served as a control group (group C). Systolic BP (SBP), diastolic BP (DBP), and mean BP (MBP), physical activity, and pulse rate were measured continuously for 36 days by use of radiotelemetric devices. RESULTS: Compared with values for clinically normal cats, SBP, DBP, and MBP were significantly increased in cats of group C. Cats in group A had significant reductions in SBP, DBP, and MBP, compared with values for cats in group C. Albuminuria but not urine protein-to-creatinine ratio was significantly correlated (R2 = 0.317) with SBP in hypertensive cats. Prevalence of ocular lesions attributable to systemic hypertension in group C (7 cats) was greater than that observed in group A (2). Two cats in group C were euthanatized on day 16 because of nuerologic complications attributed to systemic hypertension. One normotensive cat in group A was euthanatized because of purulent enteritis of unknown cause on day 27. CONCLUSIONS AND CLINICAL RELEVANCE: Amlodipine had an antihypertensive effect in cats with coexistent systemic hypertension and renal insufficiency. Its use may improve the prognosis for cats with systemic hypertension by decreasing the risk of ocular injury or neurologic complications induced by high BP.     

Use of a circular external skeletal fixator for stifle arthrodesis in a dog

Arthrodesis of the right stifle was performed in a 21 kg German shepherd dog that had sustained a comminuted fracture of the lateral femoral condyle as a result of a gunshot wound. The arthrodesis was stabilised with a circular external skeletal fixator. A simplified technique to facilitate creation of the osteotomies of the femur and tibia, and positioning of the stifle at the desired angle, is described. Compression of the subchondral bone surfaces of the distal femur and proximal tibia was achieved using tensioned coiled transarticular Kirschner wires. Arthrodesis of the stifle was confirmed radiographically 21 weeks following surgery, and the fixator was removed. After union of the arthrodesis and removal of the fixator, the dog was fully weightbearing when standing or walking, and intermittently weightbearing or non-weightbearing at faster gaits.     

Acetabular component orientation as an indicator of implant luxation in cemented total hip arthroplasty

OBJECTIVE: To determine the sensitivity and specificity with which acetabular component angles of inclination and version could be used, alone or in combination, to predict luxation of cemented total hip arthroplasties (THA). STUDY DESIGN: Comparison of retrospectively selected cases and controls SAMPLE POPULATION: All THA performed at the University of Florida between 1991 and 1998 with the BioMedtrix system and for which at least 2 months of radiographic follow-up were available. All THA performed at the University of Georgia with the BioMedtrix system which subsequently luxated. METHODS: Acetabular component inclination angle (IA) and acetabular version angle (VA) were determined for each THA. Data were grouped according to outcome - luxation or no luxation - with the luxated cases from the 2 institutions pooled. Receiver operator characteristic (ROC) analysis was used to evaluate decision rules for using IA and VA as tests for detecting postoperative luxation. Sensitivity and specificity for luxation and 95% confidence bounds were computed with selected values of IA and VA as cut-points. RESULTS: The nonluxation group consisted of 68 THA with a median follow-up time of 5 months (range, 2-60 months). The luxation group consisted of 12 THA with a mean time to luxation of 36 days. The nonluxation group had a mean +/- standard deviation (SD) IA and VA of 40.3 degrees +/- 8.9 degrees and 71.1 +/- 13.6 degrees, respectively, whereas the luxation group had a mean +/- SD IA and VA of 34.7 degrees +/- 12.6 degrees and 72.9 degrees +/- 16.6 degrees, respectively. An IA cut-point of 37.8 degrees achieved 58.3% sensitivity and 57.4% specificity. A VA cut-point of 73 degrees achieved 75.0% sensitivity and 51.5% specificity. IA and VA considered simultaneously achieved a 50.0% sensitivity and 88.2% specificity. CONCLUSIONS AND CLINICAL RELEVANCE: ROC analysis indicated that both IA and VA considered individually or simultaneously were poor indicators of luxation. Although extreme values of IA may predict luxation with high specificity, the potential for luxation cannot be excluded based on apparently appropriate values of IA and VA. The results of this study also indicate that a successful outcome is possible with a wide range of acetabular component positions.     

Effects of Body Condition and Protein Supplementation on LH Secretion and Luteal Function in Sheep

In ruminants, nutrition is one of the exogenous inputs affecting reproductive function at different levels of the hypothalamic-hypophyseal-gonadal axis. However, the exact mechanisms or even the identification of the signalling metabolic compounds by which nutrition affects reproductive function still need further clarification. The role of static body condition (BC) and its interaction with a short-term protein supplementation (PL), on secretion of metabolic hormones [growth hormone (GH), insulin and insulin-like growth factor-1 (IGF-1)], as well as on secretion of LH and progesterone (P4) was evaluated in sheep. Twenty-four Rambouillet ewes divided into two groups, with lower (LBC) and higher body condition (HBC), were randomly assigned within BC to one of two PL levels: low (LPL, 24% of crude protein; 14 g/animal/day), and high (HPL, 44% of crude protein; 30 g/animal/day). The secretion of GH, insulin, IGF-1 and LH was evaluated on day 10 of the oestrous cycle; appearance and timing of oestrous behaviour were previously detected using rams. Progesterone secretion was evaluated on day 13 of the same cycle. No differences were found (p > 0.05) between PL groups on serum GH concentrations during the sampling period (overall mean of 4.0 +/- 0.3 ng/ml), but a trend for lower values in HBC sheep was found (3.6 +/- 0.4 vs 4.4 +/- 0.4 ng/ml, p = 0.06). A BC effect was observed (p < 0.05) on serum IGF-1 level, with higher values in HBC sheep (p < 0.05). Neither BC nor PL affected (p > 0.05) secretion of LH and the number of corpora lutea, nor serum P4 and insulin concentrations. Results indicate a predominance of the static component of nutrition on sheep metabolic hormone responses, GH and IGF-1, with no effect of short-term PL on secretion of pituitary and ovarian hormones as well as luteal number and activity.     

Follicular Dynamics in Heifers during Pre-pubertal and Pubertal Period Kept under Two Levels of Dietary Energy Intake

The objective of this study was to characterize follicular dynamics in pre-pubertal, pubertal and post-pubertal periods, as well as the effect of high-energy intake on follicular development and age at puberty in heifers. Thirty-one Nelore (Bos indicus) heifers, 6 months old, were randomly assigned to receive two different diets: one of low (GI) and other of high dietary energy intake (GII). Animals were evaluated in relation to body weight gain by being weighed every 21 days. Heifers were evaluated every other day by real-time linear ultrasonography to characterize ovarian structures development from weaning to post-pubertal period. Blood samples were collected to determine plasmatic concentrations of progesterone by RIA method. The ovulation was determined when progesterone concentrations were >1 ng/mL in three consecutive samples, and by ultrasound images of corpus luteum; and oestrous behaviour in some animals. Age at puberty differed among heifers of GII (17.00 +/- 0.46 months) compared with heifers of GI (19.87 +/- 0.47 months; p < or = 0.05). Maximum size of the dominant follicles at pre-pubertal period was greater in GII heifers than in GI (10.52 +/- 0.33 and 9.76 +/- 0.15 mm, respectively; p < or = 0.05). As heifers approached first ovulation time, size of dominant follicle increased (11.75 +/- 0.37 mm for GI and 12.52 +/- 0.91 mm for GII; p < or = 0.05). Body weight at puberty was not different in both groups (302.33 +/- 27.31 kg for GI and 326.19 +/- 27.78 kg for GII heifers; p > 0.05). We conclude that animals receiving high dietary energy intake attained the puberty earlier and the development of follicles were different than in low dietary energy intake.