Computed Tomography or Magnetic Resonance Imaging‐Assisted Partial Hoof Wall Resection for Keratoma Removal

Objectives: To (1) describe the computed tomography (CT) and magnetic resonance imaging (MRI) appearance of keratomas; (2) describe a CT‐ or MRI‐assisted partial hoof wall resection technique for removal of keratomas; and (3) evaluate the morbidity and postoperative outcome of these horses. Study Design: Case series. Animals: Horses (n=10) with keratoma. Methods: Data retrieved from medical records included signalment, lameness duration and grade, physical and diagnostic evaluation findings, CT and MRI technique and findings, surgical details, histopathologic diagnosis, postoperative treatment, and complications experienced. Long‐term outcome was obtained by telephone interviews of owners. Results: Complications including excessive granulation tissue formation and infection were seen in 2 horses (20%). No keratoma recurrence occurred. Follow‐up information was available for 8 horses; 7 were sound and had resumed work. Mean time until they became sound was 2.7 months, and mean time until work resumed was 3.6 months. Conclusions: CT and MRI can be used to accurately identify the location of keratomas. Postoperative complications may be decreased by creating smaller hoof wall defects, filling the defects with antimicrobial‐impregnated polymethylmethacrylate, and placing a shoe early in the postoperative period.     

Cellular and subcellular compartmentation of sulphate in leaves in relation to low sulphur mobility

Tracer kinetics and single cell sampling both suggest that S is compartmented differently in vacuoles of epidermal and mesophyll cells. Cytoplasmic S turns over rapidly, but vacuolar turnover in both cell types is too slow to support plant growth, thus accounting in part for the apparent low mobility of S in mature leaves.     

Preanalytical variables affecting the measurement of serum paraoxonase-1 activity in horses

Paraoxonase-1 (PON-1) activity is a new inflammatory and oxidative marker. Technical effects and biological factors could affect the accuracy of PON-1 activity measurement. We investigated the effects of storage at different temperatures, repeated freeze–thaw cycles, interferences from hemolytic, lipemic, and icteric samples, and seasonal effects on PON-1 activity in horses. We evaluated 2 substrates with an automated spectrophotometer. Ten equine serum samples were stored under different conditions. Although storage at room (21°C) or refrigeration (4°C) temperature induced a statistically significant decrease (p < 0.05) in PON-1 activity, this is not diagnostically relevant. PON-1 activity in frozen samples (−20°C) was stable for short-term storage; diagnostically significant (p < 0.01) fluctuations were observed after 1 mo. Four repeated freeze–thaw cycles were assessed, and all cycles affected PON-1 activity (p < 0.01); however, this was diagnostically significant only after the 4th cycle. Hemolysis induced an overestimation of PON-1 activity; lipemia and hyperbilirubinemia did not change PON-1 activity. Thirty-four horses were sampled monthly for 1 y, and PON-1 activity was higher in autumn (p < 0.05) and winter (p < 0.05) than in spring and summer.     

Border disease: a sequential study of surviving lambs and an assessment of its effect on profitability.

Pregnant Dorset horn gimmers inoculated with a non-cytopathic strain of the border disease virus produced "hairy shaker" lambs that were individually affected to a varying degree. Surviving lambs were observed for a period of up to 20 weeks when neurological signs were seen to gradually disappear. During this time live virus was isolated from a wide variety of sites in nearly all of the infected lambs. The infected animals grew at a significantly slower rate compared with the controls, particularly during the first 15 weeks. Several morphological defects are described the most consistent being the decreased weight of the central nervous system. By 20 weeks body-weights were about 20 per cent lower and carcase quality scores were reduced. An assessment is made of the economic losses attributable to BD taking into consideration carcase quality at 20 weeks and the perinatal losses.     

Proteoglycan synthesis and content in articular cartilage and cartilage repair tissue in horses

Hexosamine concentration, DNA concentration, and [35S]sulfate incorporation for articular cartilage obtained from various sites in the metacarpophalangeal and carpal joints of horses were measured. The same measurements were made on the repair tissue filling full-thickness articular defects in the intermediate carpal bone and on cartilage surrounding partial-thickness defects 6 weeks after the defects were created arthroscopically. Cellularity (measured as DNA concentration), proteoglycan content (measured as hexosamine concentration), and proteoglycan synthesis (measured as [35S]sulfate incorporation) varied according to the site sampled. Cartilage from the transverse ridge of the head of the third metacarpal bone and the radial facet of the third carpal bone had the lowest hexosamine concentration, whereas rate of proteoglycan synthesis was lowest in cartilage from the transverse ridge of the head of the third metacarpal bone and the distal articular surface of the radial carpal bone. Repair tissue filling a full-thickness cartilage defect at 6 weeks was highly cellular. It was low in proteoglycan content, but was actively synthesizing these macromolecules. In contrast, the cartilage surrounding a partial-thickness defect was unchanged 6 weeks after the original defect was made.     

Experimental infection of dogs with Brucella abortus: effect of exposure dose on serologic responses and comparison of culture methods

Two studies of experimentally induced Brucella abortus infections in dogs are reported. Twenty dogs in experiment 1 were fed approximately 4.8 X 10(10) colony forming units of B. abortus strain 2308 (BA 2308), and 11 dogs in experiment 2 were fed approximately 3.4 X 10(14) BA 2308. Serum samples from each infected dog and noninfected control were tested on the day of infection and at weekly and biweekly intervals post-infection (PI) for antibodies to B. abortus. The standard tube agglutination (STA) and rivanol (RIV) mean log-titers of the infected dogs in the 2 experiments were compared statistically on the day of infection and on PI days 7, 14, 21, 35, 42 and 49. The STA and RIV titers of the infected dogs in experiment 2 were significantly higher than were those of the dogs in experiment 1. Brucella abortus was isolated from 29 infected dogs in experiments 1 and 2 including 10 dogs, which were seronegative when cultured.