Investigation of oxygen-derived free radical generation in cancellous bone specimens obtained from dogs.

Generation of free radicals and the ability of various antioxidants to attenuate radical production in freshly procured cancellous bone specimens was investigated, using spin-trapping and electron spin resonance (ESR) techniques. Seven core cancellous bone specimens, 10 mm long and 7.9 mm in diameter, were obtained using aseptic technique, from the proximal portion of the humerus of 9 adult mixed-breed dogs. One core cancellous bone specimen from each dog was incubated in spin trap alpha-phenyl-N-tert-butylnitrone in Eagle's minimum essential medium and served as a control. The other 6 specimens from each dog were incubated in alpha-phenyl-N-tert-butylnitrone/Eagle's minimum essential medium plus 1 of the following antioxidants: superoxide dismutase, catalase, superoxide dismutase/catalase, indomethacin, allopurinol, or deferoxamine mesylate. All specimens were incubated at 26 C for 90 minutes, then frozen at -20 C until they were prepared for analysis by ESR spectroscopy. Each specimen was thawed, homogenized, and extracted in a low-dielectric organic solvent prior to obtaining an ESR spectrum which was analyzed for hyperfine splitting constants to identify radicals. Each first-derivative spectrum was digitally double-integrated to obtain an area: these areas were used to compare intensities of the spin. For each treatment group, the areas from the treated specimens were compared with the areas from the control specimens, using a paired t-test. Significance was accepted at P < or = 0.05. Spin adducts were detected in all cancellous bone specimens. Specimens incubated in deferoxamine (P = 0.0017) and superoxide dismutase/catalase (P = 0.0452) had significantly smaller areas than did control specimens.(ABSTRACT TRUNCATED AT 250 WORDS)

Internal fixation of comminuted transverse scapular fracture in a foal.

A comminuted scapular fracture in a foal was treated surgically by use of 2 dynamic compression plates. The plates were applied upside down, so that the convex surface of the plate faced the bone. At 5 months after surgery, the plates were removed, and the foal recovered without complications.

Arthrodesis of metatarsophalangeal joints in a dog.

Chronic osteomyelitis and septic arthritis involving the 3rd and 4th metatarsophalangeal joints were diagnosed in a Doberman Pinscher. Arthrodesis of the 3rd and 4th metatarsophalangeal joints resulted in a subtle persistent gait abnormality, but limb function was preserved. Arthrodesis of metatarsophalangeal joints is an alternative to amputation, especially when main weight-bearing digits are involved.

Osteochondritis dissecans of the lateral ridge of the talus in a dog.

Osteochondral fragments, which originated from the proximolateral ridge of the talus, were discovered in an 8-month-old Rottweiler. A large fragment was reattached, using a lag screw and wire. Microscopic examination of a small fragment suggested the lesion resulted from osteochondritis dissecans. Stabilization of the major fragment resulted in acceptable joint function.

Use of methyl methacrylate orbital prostheses in dogs and cats: 78 cases (1980-1986).

To prevent cosmetically undesirable orbital concavity after enucleation, methyl methacrylate spheres were implanted into the orbits of 73 dogs and 5 cats. In all cases, follow-up reports were obtained until suture removal 2 weeks after surgery, and for 58 animals (79%) until 6 months after surgery. Information was available for 46 animals (60%) 1 year after surgery, 28 animals (36%) 2 years after surgery, and 7 animals (9%) 3 years after surgery. Implants failed in 3 dogs and 2 cats. Complications were not detected in the remaining 73 animals (93%), and owners were pleased with the cosmetic results. The causes of implant failure in dogs varied; however, in cats, fluid accumulation was the consistent complication associated with failure. Orbital implantation of methyl methacrylate spheres was found to be a safe, practical, and inexpensive method of improving the cosmetic appearance of dogs requiring enucleation. Although the number of cats evaluated was limited, the accumulation of orbital fluid in a high percentage of those suggested that orbital implants may be less successful in this species.

False ankylosis of the temporomandibular joint in a cat.

Progressive inability to open the mouth developed in a cat after trauma to the head. Evaluation revealed a healed depression fracture of the left zygomatic arch and normal temporomandibular joints. Surgical exploration of the fracture confirmed a false ankylosis that developed between the depression fracture and the ramus of the mandible. Treatment included excision of the central portion of the zygomatic arch and a portion of the ramus. The cat regained normal function of its mouth.

Bronchoesophageal fistula and transient megaesophagus in a dog.

Bronchoesophageal fistula and megaesophagus were diagnosed in a dog. Within 2 days after surgical correction of the bronchoesophageal fistula, peristalsis in the thoracic portion of the esophagus returned to normal and the esophagus resumed its normal size. The cause of the fistula was attributed to damage from a foreign body. The cause of the transient megaesophagus likely was related to the bronchoesophageal fistula.

Ocular changes in a cat with disseminated blastomycosis.

A domestic shorthair cat examined because of dyspnea was found to have ophthalmoscopic and radiographic changes suggestive of systemic mycosis. The cat died despite antifungal therapy. Histologic examination revealed Blastomyces dermatitidis in the eyes, brain, lungs, stomach, liver, kidneys, spleen, pancreas, and adrenal glands. The pathologic changes were similar, but more widespread than those typically seen with canine blastomycosis.