Transplantation of the Canine Distal Ulna as a Free Vascularized Bone Graft

An autogenous free vascular bone graft of the canine distal ulna was evaluated. The vascularity of the graft was based on a musculoperiosteal sheath supplied solely by the caudal interosseous artery and vein. Four autogenous heterotopic (ulna to tibia) vascular transfers were performed. Two avascular transfers were performed to provide baseline criteria from which the success of vascularized transfers could be assessed. Clinical lameness evaluation, serial radiographs, bone scintigraphy, and sequential fluorochrome bone labeling were performed after surgery in both vascular and avascular transfers. All dogs were free of lameness in the donor limb by the 26th postoperative day. Serial radiographs revealed rapid graft incorporation and hypertrophy in all vascularized grafts and severe bone resorption in nonvascularized grafts. Histology, microangiography, and evaluation of fluorochrome bone labels were performed 90 days after surgery to determine graft viability, incorporation and temporal remodeling patterns. Microangiography and fluorochrome assessment complemented the histological findings. Based on these findings the distal ulnar bone graft was determined to be both viable and structurally adequate for selected cases of long bone reconstruction.     

Retropharyngeal lymph node infection in horses: 46 cases (1977–1992)

SUMMARY A retrospective study of 46 horses with retropharyngeal lymph node (RPLN) infection presented to the Rural Veterinary Centre between 1977 and 1992 was undertaken. Horses aged less than one year were most commonly represented (46%). Thirty-nine percent of cases had been exposed to horses with confirmed or suspected strangles (Streptococcus equi subsp equi infection) within the previous 8 weeks. Most frequent signs were unilateral or bilateral swelling of the throat region (65%), respiratory stertor/dyspnoea (35%), purulent nasal discharge (20%), inappetence and signs of depression (15%), and dysphagia (9%). All horses had a soft tissue density in the retropharyngeal region on radiographs. Rhinopharyngoscopy, ultrasonography, haematology as well as cytological and microbial analysis of material aspirated from the soft tissue swelling facilitated diagnosis in some horses. Fifteen horses (33%) were treated with procaine penicillin intramuscularly for 4 to 7 days followed by oral trimethoprim-sulphadimidine for 7 to 14 days. Non-steroidal anti-inflammatory drugs were administered to 6 horses. Four required tracheostomy for severe respiratory distress. The 15 horses treated medically responded to treatment and were discharged from hospital. Three horses (6%) with mild signs received no treatment and recovered uneventfully. Twenty-eight horses (61%) underwent general anaesthesia and surgical drainage of a RPLN abscess. Nineteen received procaine penicillin G for 4 to 7 days. Four of the nine horses that did not receive antibiotic treatment after surgery required further surgical drainage 10 days to 7 weeks after the initial surgery . Limited follow-up information was available for 37 horses. Thirty-two horses were considered to have made complete recovery, 3 horses had died through misadventure and 2 had been euthanased because of chronic ill-thrift .     

Comparison of etorphine-detomidine and medetomidine-ketamine anesthesia in captive addax (Addax nasomaculatus).

Thirty-five anesthetic events involving 15 captive addax (Addax nasonzaculatus) were performed between August 1998 and February 2002 using a combination of etorphine (33.7 +/- 7.9 microg/kg) and detomidine (21.9 +/- 4.6 microg/ kg) or a combination of medetomidine (57.4 +/- 8.6 microg/kg) and ketamine (1.22 +/- 0.3 microg/kg), with or without supplemental injectable or inhalant anesthetic agents. Etorphine-detomidine anesthesia was antagonized with diprenorphine (107.1 +/- 16.4 microg/kg) and atipamezole (100.9 +/- 42.4 microg/kg). Medetomidine-ketamine anesthesia was antagonized with atipamezole (245.3 +/- 63.4 microg/kg). Animals became recumbent within 5 min when the combination of etorphine and detomidine was used and within 11 min when the combination of medetomidine and ketamine was used. Both drug combinations were suitable for use as primary immobilizing agents producing short-duration restraint and analgesia. Bradycardia was noted with both combinations. Further investigation of the cardiopulmonary effects of both combinations is warranted.     

Half-Body Radiotherapy in the Treatment of Canine Lymphoma

In a Phase I-II study, half-body radiotherapy was used to treat 14 dogs with multicentric lymphoma. Using this technique, a radiation dose of 7 Gray (Gy) was delivered to one half of the body in a single exposure. The other half of the body was treated approximately 28 days later. Of 14 treated dogs, 11 (79%) had a measurable decrease in tumor size. Five dogs achieved a complete or partial remission with a mean duration of 102 and 54 days, respectively. In predicting response to therapy, poor prognostic factors included large tumor burdens, advanced disease stage, and chemotherapy-resistant tumors. Side effects of treatment were divided chronologically into acute (radiation sickness, tumor lysis), subacute (bone marrow suppression), and chronic (radiation pneumonitis, lymphoma-cell leukemia) syndromes. Complications were more severe in tumor-bearing dogs when compared with healthy control animals. Dogs with small tumor burdens and minimal internal disease had fewer complications compared with those with more advanced disease.     

Embedding of skeletal tissue in plastic for vascular and histological study to demonstrate delayed endochondral ossification in Leghorn type fowl

A method is described which enables visualisation of the blood supply in developing avian long bones, followed by the preparation of undecalcified histological sections from the same material. The circulatory system was perfused with a solution of fixative, dye and barium sulphate. The skeletal tissue was cleared in plastic resin before embedding and tissue blocks were cut into 1 mm slabs. The vascular canals were then examined with a dissecting microscope. Slabs were re-embedded in resin and 5 microns sections cut for routine undecalcified histological staining. Focal areas of delayed endochondral ossification were demonstrated in slabs prepared from the proximal ends of femora of White Leghorns. These lesions are considered a less severe form of the dyschondroplastic condition occurring in broilers.     

Application of a modified indirect fluorescent antibody test to the detection of antibodies to bovine respiratory syncytial virus in Ontario cattle.

A modified indirect fluorescent antibody test for the detection of serum antibodies to bovine respiratory syncytial virus was developed. The test made use of Terasaki plastic microtiter plates in which bovine respiratory syncytial virus (Saskatchewan strain) infected Georgia bovine kidney cells were grown and fixed in situ by a modified acetone fixation procedure. Evans blue dye was used as a counterstain to reduce nonspecific fluorescence. In a study of 986 field sera from a geographically broad cross-section of mature Ontario cattle, 95% of the samples were found to be positive at or above a 1:2 dilution. No seronegative regions, counties or herds were identified. When representative samples covering a range of indirect fluorescent antibody titers were further examined by a microtiter virus neutralization assay, a significant agreement was found between the two tests. Up to a fourfold decrease in titer was observed when antigen coated plates were stored at -70 degrees C for four months. The modified indirect fluorescent antibody test for bovine respiratory syncytial virus antibody detection proved to be a rapid, practical procedure for use in the diagnostic laboratory. This study confirms that bovine respiratory syncytial virus is widespread in the Ontario cattle population and that most mature cattle can be assumed to have been exposed to this virus.     

Pseudomonas aeruginosa sepsis in an adult horse with enteric Salmonellosis

Objective: To report a case of enteric Salmonellosis and Pseudomonas aeruginosa bacteremia in an adult horse. Case summary: A 7‐year‐old mare presented for signs of acute abdominal pain. Exploratory laparotomy allowed surgical correction of right dorsal displacement of the large colon with a 180° volvulus at the cecocolic ligament. Postoperatively, the mare developed fevers, leukopenia, and diarrhea. Salmonella newport was cultured from the feces and P. aeruginosa from 2 consecutive blood cultures. The mare responded well to intensive medical therapy. New or unique information provided: Bacteremia associated with colitis is unusual in an adult horse, although the percentage of animals that may be bacteremic is unknown. The bacteria isolated, P. aeruginosa, a common pathogen of other sites in the horse, has not, to our knowledge, been previously reported as a cause of bacteremia and septicemia in an adult horse.     

Response of vegetation and fire to Little Ice Age climate change: regional continuity and landscape heterogeneity

Late-Holocene climatic conditions in the upper Great Lakes region have changed sufficiently to produce significant changes in vegetation and fire regimes. The objective of this study was to determine how the vegetation mosaic and fire regimes on an oak (Quercus spp.)- and pine (Pinus spp.)-dominated sand plain in northwestern Wisconsin responded to climatic changes of the past 1,200 years. We used pollen and charcoal records from a network of sites to investigate the range of natural variability of vegetation on a 1,500-km² landscape on the southern part of the sand plain. A major vegetation shift from jack pine (Pinus banksiana) and red pine (P. resinosa) to increased abundance of white pine (P. strobus) occurred between 700 and 600 calendar years before present (cal yr BP), apparently corresponding to more mesic conditions regionally. A decrease in charcoal accumulation rate also occurred at most sites but was not synchronous with the vegetation change. At some sites there were further changes in vegetation and fire regimes occurring ～500–300 cal yr BP, but these changes were not as strong or unidirectional as those that occurred 700–600 cal yr BP. Our results suggest that both the composition and the distribution of vegetation of the southern part of the sand plain have been sensitive to relatively small climatic changes, and that the vegetation at the time of European settlement was a transitory phenomenon, rather than a long-term stable condition.     

Osseous metaplasia in the eye of a dog

Incisional iris biopsy was performed for diagnosis of an unusual opaque white mass protruding from the right ventrolateral iris of a 10-year-old neutered male Great Dane dog. Histopathology revealed a diagnosis of bone formation within otherwise normal iris tissue. No underlying etiology was identified. Osseous metaplasia or heterotopic bone formation may be an additional differential diagnosis for a nonneoplastic mass in the eye of a dog.