Paranasal sinus surgery through a frontonasal flap in sedated, standing horses

OBJECTIVE: To report experience with paranasal sinus surgery through a frontonasal flap in sedated, standing horses. STUDY DESIGN: Treatment of 10 horses with naturally occurring paranasal sinus disease through a frontonasal bone flap created with the horses standing. ANIMALS: Ten adult horses. METHODS: After restraint and sedation, local anesthetic was injected subcutaneously along the proposed incision line over the conchofrontal sinus and was instilled into the sinuses through a small hole created in the frontal bone. A 3-sided, rectangular, cutaneous incision that extended through the periosteum was created over the frontal and nasal bones. The incision was extended into the conchofrontal sinus using a bone saw, and the base of the flap, on the midline of the face, was fractured. The sinuses were explored, and the horse was treated for the disease encountered. The flap was repositioned; subcutaneous tissue and skin were sutured separately. RESULTS: The horses had few signs of discomfort during creation of the bone flap and during disease treatment. Diseases encountered included inspissated exudate in the ventral conchal sinus (five horses), feed and exudate throughout the sinuses (one horse), occlusion of the nasomaxillary aperature (one horse), polyp (one horse), osteoma (one horse), and progressive ethmoidal hematoma (one horse). CONCLUSION: In selected cases, surgery of the paranasal sinuses can be performed safely on sedated and standing horses through a frontonasal bone flap. CLINICAL RELEVANCE: Performing surgery through a frontonasal bone flap with the horse standing and sedated, rather than anesthetized, eliminates risks and expense of general anesthesia.     

The effects of methylprednisolone on normal and monocyte-conditioned medium-treated articular cartilage from dogs and horses

OBJECTIVE: To study in vitro (1) the dose-response relationships between proteoglycan metabolism in normal and corticosteroid-treated articular cartilage; (2) long-term proteoglycan metabolism after treatment of articular cartilage with corticosteroids; and (3) the effect of corticosteroids on proteoglycan metabolism in articular cartilage treated with monocyte-conditioned medium (MCM). STUDY DESIGN: Equine and canine articular cartilage explants were treated with corticosteroids and MCM. Proteoglycan synthesis and degradation were measured by radioactive labeling in short-term culture, and the long-term effect of corticosteroid treatment on proteoglycan metabolism was studied in normal explants. ANIMALS: Two young cross-breed horses and 3 young Labrador retrievers. METHODS: Equine articular cartilage explants were incubated in medium containing methylprednisolone sodium succinate (MPS) at 0, .001, .01, .1, 1, and 10 mg/mL (final concentration) for 1 day and then in fresh medium without MPS. Proteoglycan synthesis was measured by incorporation of sodium [35S]sulfate at 1, 3, 7, 10, and 13 days after initial treatment with MPS. Proteoglycan release was measured from separate explants prelabeled with sodium [35S]sulfate and treated similarly. Equine articular cartilage explants were treated with equine MCM simultaneously with, and 24 hours before MPS, at 0, 0.01, 0.1, 1, or 5 mg/mL for 72 hours. Proteoglycan synthesis and degradation in these explants was compared. Proteoglycan synthesis and degradation were measured similarly in canine articular cartilage explants treated simultaneously with canine MCM and MPS at 0, 0.001, 0.01, 0.1, 1 and 10 mg/mL for 72 hours. Equine articular cartilage explants treated with 0, 0.01, 0.1, 1, and 5 mg/mL of MPS for 72 hours were evaluated histologically. RESULTS: Proteoglycan synthesis in normal equine articular cartilage was severely depressed by 10 mg/mL MPS for 24 hours, and proteoglycan synthesis failed to recover after 13 days of culture in medium without MPS. Cartilage treated with 5 mg/mL MPS had pyknotic chondrocyte nuclei and empty lacunae. Concentrations of 1 and 0.1 mg/mL MPS depressed proteoglycan synthesis in normal equine cartilage explants. For these 2 concentrations, proteoglycan synthesis recovered 2 days after MPS removal and increased significantly (P < .05) 7 days after treatment with MPS compared with controls without MPS. Concentrations of 0.001 and 0.01 mg/mL MPS did not significantly affect proteoglycan synthesis in normal equine cartilage explants. Cumulative proteoglycan loss over 13 days in culture from normal equine explants treated for 24 hours with different concentrations of MPS was not significantly different between treatment groups at any time point. MCM significantly depressed proteoglycan synthesis in both canine and equine articular cartilage explants and significantly increased proteoglycan release. These effects were prevented in the canine explants by simultaneous treatment with MPS at 1 and 0.1 mg/mL, and proteoglycan release induced by MCM in equine articular cartilage was inhibited by 1 mg/mL MPS. CONCLUSIONS: Concentrations of 1.0 and 0.1 mg/mL MPS alleviated articular cartilage degradation in MCM-treated articular cartilage in vitro. These concentrations of MPS in contact with normal cartilage explants for 24 hours are unlikely to be detrimental in the long term to proteoglycan synthesis. The response of articular cartilage to MPS was affected by treatment with MCM so that results of experiments with normal articular cartilage explants may not reflect results obtained with abnormal cartilage. CLINICAL RELEVANCE: It may be possible to find an intraarticular concentration of corticosteroid that protects articular cartilage against cytokine-induced matrix degradation yet not have prolonged or permanent detrimental effects on chondrocyte matrix synthesis.     

Efficacy of selamectin in the treatment and prevention of flea (Ctenocephalides felis felis) infestations on dogs and cats housed in simulated home environments

The efficacy of selamectin, a novel avermectin, in protecting dogs and cats against experimentally induced environmental flea (Ctenocephalides felis felis) infestations, was evaluated in a series of controlled and masked studies. Purpose-bred shorthaired cats and Beagles were randomly allocated to treatment with either selamectin at a minimum dosage of 6mgkg(-1) of body weight in the commercial formulation or the negative control treatment (vehicle only), and housed in controlled simulated home environments capable of supporting the flea life cycle. Day 0 was defined as the first day of treatment. Treatments were administered topically in a single spot on the skin at the base of the neck in front of the scapulae. In environmental challenge studies, which were designed to evaluate the efficacy of selamectin in the treatment and control of established flea infestations, dogs and cats were each infested with 100 fleas on days -28 and -21 and placed in carpeted rooms in order to establish high levels of active flea infestation prior to day 0. Treatments were administered monthly for 3 months. Flea comb counts were performed on days 14, 29, 44, 59, 74, and 90. Reductions in geometric mean flea comb counts for selamectin, compared with vehicle, were >99% from day 14 onwards for dogs, and >92% on day 29 and >99% on days 44, 59, 74, and 90 for cats (P=0.0001). In prevention of environmental infestation studies, dogs and cats were placed in environments capable of supporting flea infestations and given monthly treatments for 2 months, commencing on day 0. Animals were infested with 100 fleas on days 1 and 7, and flea comb counts were performed on days 29, 44, and 60. Reductions in geometric mean flea comb counts for selamectin, compared with vehicle, were >99% on days 29, 44, and 60 (P=0.0001) for dogs and cats. Monthly administration of selamectin to dogs and cats housed in environments highly suited to completion of the flea life cycle was shown to be highly effective in the treatment and prevention of flea infestations, without the need for supplementary environmental control measures.     

Effects of ring diameter and wire tension on the axial biomechanics of four-ring circular external skeletal fixator constructs.

OBJECTIVE: To determine relative effects of ring diameter and wire tension on axial biomechanical properties of 4-ring circular external skeletal fixator constructs. SAMPLE POPULATION: 4-ring circular external skeletal fixator constructs and artificial bone models. PROCEDURE: 4-ring constructs were assembled, using 50-, 66-, 84-, or 118-mm-diameter rings. Two 1.6-mm-diameter fixation wires were attached to opposing surfaces of each ring at intersection angles of 90 degrees and placed through a gap-fracture bone model. Three examples of each construct were loaded in axial compression at 7 N/s to a maximum load of 400 N at each of 4 wire tensions (0, 30, 60, and 90 kg). Response variables were determined from resulting load-displacement curves (construct stiffness, load at 1 mm of displacement, displacement at 400 N). RESULTS: Ring diameter and wire tension had a significant effect on all response variables and had a significant interaction for construct stiffness and displacement at 400 N. Significant differences within all response variables were seen among all 4 ring diameters and all 4 wire tensions. As ring diameter increased, effect of increasing wire tension on gap stiffness and gap displacement at 400 N decreased. Ring diameter had a greater effect than wire tension on all response variables. CONCLUSIONS AND CLINICAL RELEVANCE: Although effects of wire tension decrease as ring diameter increases, placing tension on wires in larger ring constructs is important because these constructs are inherently less stiff. The differential contribution of ring diameter, wire tension, and their interactions must be considered when using circular external skeletal fixators.     

Campylobacter-like organisms isolated from gastric mucosa of ferrets

Campylobacter-like organisms (CLO) were isolated from gastric lesions in 1 ferret and gastric mucosa of 2 healthy ferrets. The organism was not isolated from biopsies of gastric mucosa of 14 other healthy ferrets, 1 of which had small gastric lesions located at the pylorus. Lesions from which CLO were isolated were located in the antrum of 1 ferret and were classified as inflammation with repair. Affected gastric tissue was highly vascularized with fibrous connective tissue surrounding irregularly shaped glands. Necrosis and ulceration of adjacent mucosa also were observed. Using Warthin-Starry stain, Campylobacter-like organisms were seen on and in the glandular epithelium of the ferret with gastric lesions from which CLO were isolated.     

Virus-neutralizing and passively protective monoclonal antibodies to infectious bursal disease virus of chickens.

Murine monoclonal antibodies (MAbs) were produced to assist in the identification and characterization of the virus-neutralizing epitopes of infectious bursal disease virus (IBDV). Only MAbs that reacted in Western blotting with viral protein 2 (VP2) or immunoprecipitated VP2 neutralized the infectivity of the virus in cell culture and passively protected young chickens from infection. Three of the neutralizing MAbs did not react with denatured viral proteins. Additivity enzyme-linked immunosorbent assays indicated that the six virus-neutralizing MAbs recognized two spatially independent epitopes. The ability of two of the virus-neutralizing MAbs to neutralize a variant of IBDV that had escaped neutralization by all the other MAbs confirmed the existence of two distinct neutralizing epitopes. The results support the hypothesis that there are at least two non-overlapping epitopes recognized by the virus-neutralizing MAbs reported in this study, although these may still be within one conformational site on VP2 of IBDV.