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Summary

A circular (5.5 mm diameter) full-thickness cartilage defect was created on the medial ridge of the talus in 12 skeletally mature dogs. In 6 dogs, the articular surface of the lesion was repaired, using an osteochondral graft obtained from the ipsilateral manus. The graft (digit I, first phalanx, distal articular surface and diaphysis) was contoured to obtain a press fit in the drilled talar recipient site. In 6 dogs, the lesion was not treated and healed by fibrous tissue replacement. Functional assessment (lameness, hock range of motion, joint stability, joint crepitus, and mid-femoral muscle circumference) was completed before surgery and at postoperative weeks 2 through 20. Radiographic assessment (periarticular soft tissue width, joint space width, osteophyte formation, and graft incorporation) was completed before surgery and at postoperative weeks 0, 6, 12, and 20. To facilitate histologic assessment, tissues were stained with toluidine blue and H&E. Histologic assessment of the articular surface on the surgically treated talus, ipsilateral tibia, and contralateral talus was completed, using a modification of the Mankin grading system. Subchondral bone was examined to assess graft viability and incorporation. Analysis of the ordinal data was completed, using a Mann-Whitney rank sum test.

All dogs were fully weight bearing by postoperative week 7. Dogs without grafts had significantly (P = 0.036) better clinical function at postoperative week 6. Significant difference in functional assessment was not evident at postoperative week 20. Immediate postoperative radiographic assessment revealed significant (P = 0.005) difference between nongrafted and grafted groups. Significant difference was not observed at postoperative week 6, 12, or 20. All grafts appeared radiographically incorporated by postoperative week 12. All grafts restored joint surface congruity, whereas 3 of 6 nongrafted lesions had poor articular congruity. Of 6 grafts, 4 partially retained normal hyaline cartilage, resulting in significantly (P = 0.014) lower Mankin grades. Significant histologic differences between groups were not apparent when the apposing tibia and control talus were examined.

Talar reconstruction by use of a phalangeal osteochondral graft is a viable surgical procedure. These data indicate that normal articular and subchondral architecture are more closely approximated by osteochondral reconstruction than by fibrous tissue repair.

Free access
in American Journal of Veterinary Research

Summary:

Twenty-two tympanic bulla osteotomies were performed in 19 cats for the treatment of bacterial otitis media (n = 11), inflammatory polyps (n = 7), or middle-ear neoplasia (n = 4). Inflammatory polyps mostly affected young adult cats (mean age, 1.5 years), whereas otitis media affected middle-aged cats (mean age, 5.5 years) and neoplasia affected older cats (mean age, 10.25 years). Although not specific for the underlying disease process, fluid density within the tympanic bulla or thickening of the bulla was observed radiographically in 100% of cats with middle-ear disease. In cats for which results were available, bacterial culturing revealed pathogens in 6 cats diagnosed with otitis media and in 7 cats with benign or malignant tumors within the bulla. The ventral approach to the bulla was the most common surgical procedure (18 osteotomies), followed by the lateral approach combined with ablation of the vertical and horizontal parts of the external acoustic meatus (4 osteotomies). Immediate postoperative complications were common but short-term, and included Horner's syndrome (11 cats), facial nerve paralysis (5 cats), and otitis interna (2 cats). Bulla osteotomy resulted in resolution of clinical signs without recurrence in cats with middle-ear polyps. Drainage of the infected tympanic cavity aided in resolution of the clinical signs of bacterial otitis media, but the long-term clinical course was characterized by persistent neurologic deficits (5 cats) and recurrence of disease (2 cats). Neoplastic infiltration of the tympanic bulla was associated with a poor prognosis, and although surgery helped to establish a diagnosis, it did not alter the clinical course of the disease. Bulla osteotomy resulted in improvement but not in resolution of head tilt in cats that had developed this sign secondary to middle-ear disease.

Free access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

SUMMARY

Transverse midshaft fractures of femurs from freshly euthanatized dogs were stabilized by means of 6 methods: (1) 3.5-mm bone plate and screws, (2) single intramedullary pin, (3) double intramedullary pins retrograded proximally and driven distally to the level of the femoral trochlea, (4) double intramedullary pins retrograded distally and driven proximally into the trochanteric region, (5) double intramedullary pinning in Rush pin fashion, and (6) multiple intramedullary pinning that filled the medullary cavity at the fracture site.

All bones were subjected to torsional stress. The measured strain was converted to forces of torque and correlated with bone diameter to normalize the data. The forces of torque from each fixation technique were compared with each other and with the mean torque force necessary to fracture intact femurs.

Torsional shear applied to plated femurs resulted in failure at a mean level of 33.8% of the calculated theoretic moment. Torsional forces were concentrated at one end of the plate and catastrophically failed at that point, whereas the fracture site remained rigidly fixed. There was no significant difference in the initial moment of torsional failure between the single intramedullary pin technique (0,05 Nm) and the double-pinning techniques (0.03 Co 0.04 Nm). The multiple-pinning technique was 1.8 to 3 times as effective in resisting rotational forces, compared with the other pinning techniques, but not significantly so.

Free access
in American Journal of Veterinary Research

Abstract

Objective—To determine the lowest ACTH dose that would induce a significant increase in serum cortisol concentration and identify the time to peak cortisol concentration in healthy neonatal foals.

Design—Prospective randomized crossover study.

Animals—11 healthy neonatal foals.

Procedures—Saline (0.9% NaCl) solution or 1 of 4 doses (0.02, 0.1, 0.25, and 0.5 μg/kg [0.009, 0.045, 0.114, and 0.227 μg/lb]) of cosyntropin (synthetic ACTH) was administered IV. Serum cortisol concentrations were measured before and 10, 20, 30, 60, 90, 120, 180, and 240 minutes after administration of cosyntropin or saline solution; CBCs were performed before and 30, 60, 120, and 240 minutes after administration.

Results—Serum cortisol concentration was significantly increased, compared with baseline, by 10 minutes after cosyntropin administration at doses of 0.1, 0.25, and 0.5 μg/kg. Serum cortisol concentration peaked 20 minutes after administration of cosyntropin at doses of 0.02, 0.1, and 0.25 μg/kg, with peak concentrations 1.7, 2.0, and 1.9 times the baseline concentration, respectively. Serum cortisol concentration peaked 30 minutes after cosyntropin administration at a dose of 0.5 μg/kg, with peak concentration 2.2 times the baseline concentration. No significant differences were detected among peak serum cortisol concentrations obtained with cosyntropin administration at doses of 0.25 and 0.5 μg/kg. Cosyntropin administration significantly affected the lymphocyte count and the neutrophil-to-lymphocyte ratio.

Conclusions and Clinical Relevance—Results suggested that in healthy neonatal foals, the lowest dose of cosyntropin to result in significant adrenal gland stimulation was 0.25 μg/kg, with peak cortisol concentration 20 minutes after cosyntropin administration.

Full access
in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the lowest ACTH dose that would induce a maximum increase in serum cortisol concentration in healthy adult horses and identify the time to peak cortisol concentration.

Design—Evaluation study.

Animals—8 healthy adult horses.

Procedures—Saline (0.9% NaCl) solution or 1 of 4 doses (0.02, 0.1, 0.25, and 0.5 μg/kg [0.009, 0.045, 0.114, and 0.227 μg/lb]) of cosyntropin (synthetic ACTH) were administered IV (5 treatments/horse). Serum cortisol concentrations were measured before and 30, 60, 90, 120, 180, and 240 minutes after injection of cosyntropin or saline solution; CBCs were performed before and 30, 60, 120, and 240 minutes after injection.

Results—For all 4 doses, serum cortisol concentration was significantly increased, compared with the baseline value, by 30 minutes after administration of cosyntropin; no significant differences were detected among maximum serum cortisol concentrations obtained in response to administration of doses of 0.1, 0.25, and 0.5 μg/kg. Serum cortisol concentration peaked 30 minutes after administration of cosyntropin at a dose of 0.02 or 0.1 μg/kg, with peak concentrations 1.5 and 1.9 times, respectively, the baseline concentration. Serum cortisol concentration peaked 90 minutes after administration of cosyntropin at a dose of 0.25 or 0.5 μg/kg, with peak concentrations 2.0 and 2.3 times, respectively, the baseline concentration. Cosyntropin administration significantly affected WBC, neutrophil, and eosinophil counts and the neutrophil-to-lymphocyte ratio.

Conclusions and Clinical Relevance—Results suggested that in healthy horses, administration of cosyntropin at a dose of 0.1 μg/kg resulted in maximum adrenal stimulation, with peak cortisol concentration 30 minutes after cosyntropin administration.

Full access
in Journal of the American Veterinary Medical Association

SUMMARY

Eighteen healthy dogs were allotted to 3 groups (n = 6 dogs each). All dogs were evaluated at the beginning of the study by complete physical examination; total and differential WBC counts; serum biochemical analysis (alanine transaminase and alkaline phosphatase activities and bilirubin and albumin concentrations); sulfobromophthalein excretion, ammonia tolerance, and glucagon response testing; portal and intraparenchymal pressure determinations; operative mesenteric portography; and histologic assessment of hepatic biopsy specimens.

The left hepatic vein was ligated completely in dogs of groups 1 and 2. Group-3 (control) dogs had a ligature placed loosely around the left hepatic vein. Dogs of groups 1 and 3 were reevaluated 24 hours after surgery by use of the aforementioned hematologic and biochemical tests. Group-1 dogs were reevaluated by use of portal and intraparenchymal pressure determinations, jejunal vein portography, and complete necropsy at 48 hours after surgery. At 4 weeks after surgery, dogs of groups 2 and 3 were reevaluated by use of all aforementioned tests.

Results indicated transient hepatic congestion, which resolved by the fourth postoperative week. Longstanding effect on hepatic structure, circulation, or function was not found. We concluded that left hepatic vein ligation in clinically normal dogs does not cause severe or permanent liver damage.

Free access
in American Journal of Veterinary Research

Objective

To determine whether there was intralesional infection or expression of FeLV or feline sarcoma virus in suspected vaccine-associated fibrosarcomas in cats.

Design

Prospective case series.

Sample Population

130 suspected vaccine-associated fibrosarcomas from cats and 1 multicentric fibrosarcoma from 1 cat.

Procedure

Excisional biopsy specimens were fixed in formalin and embedded in paraffin. Expression of FeLV antigen was assessed, using a polyclonal goat anti-FeLV glycoprotein 70 (gp 70) serum and an avidin-biotin immunoperoxidase staining technique. The FeLV genome was detected with a polymerase chain reaction (PCR), using primers targeted to a conserved sequence in the untranslated region of the long terminal repeat (LTR) of the FeLV.

Results

FeLV gp 70 and LTR sequence were detected in a multicentric fibrosarcoma. All 130 of the suspected vaccine-associated fibrosarcomas were FeLV gp 70 negative on the basis of immunohistochemical test results; 100 fibrosarcomas also were examined by use of PCR and were negative for FeLV LTR region.

Clinical Implications

Exogenous retroviruses, FeLV, and feline sarcoma virus were not detected in these suspected vaccine-associated fibrosarcomas, using immunohistochemistry and PCR. Additional testing will be required to determine the nature of genomic alterations that are involved in the oncogenesis of vaccine-associated fibrosarcomas in cats. (J Am Vet Med Assoc 1996;209:767–771)

Free access
in Journal of the American Veterinary Medical Association

SUMMARY

The immunotherapeutic effect of low-dose human alpha interferon on viral shedding and clinical disease was evaluated in horses inoculated with equine herpesvirus- 1 (ehv-1). Eighteen clinically healthy weanling horses, 5 to 7 months old, were allotted to 3 equal groups. Two groups were treated orally with human α-2a interferon (0.22 or 2.2 U/kg of body weight), on days 2 and 1 before inoculation with ehv-1, the day of inoculation, and again on postinoculation day 1. The horses of the remaining group were given a placebo orally on the same days. The horses were monitored daily for changes in body temperature and for clinical signs of respiratory tract disease. Blood and nasal swab specimens were collected daily for virus isolation. Blood was also collected at intervals throughout the monitoring period for evaluation of cbc, serum IgG and IgM concentrations, and antibody titers to ehv-1. Febrile responses, nasal discharge, viral shedding, changes in cbc, and an increase in antibody titers to ehv-1 were noticed in all horses after inoculation. There was no significant difference (P > 0.05) in mean values of the factors measured between treatment and control groups.

Free access
in American Journal of Veterinary Research