Clinical evaluation of dogs after surgical and nonsurgical management of osteochondritis dissecans of the talus

Osteochondritis dissecans of the medial aspect of the talus was diagnosed in 17 joints in 11 dogs. In 10 of the 11 dogs, intermittent lameness had persisted after initial diagnosis and therapy. Radiographs made during the initial examination showed a widening of the medial tarsocrural joint space, with osteophyte formation involving the medial and caudal tarsocrural joint. The follow-up radiographs showed greatest change in the increase in reactive bone formation, especially involving the medial and caudal aspects of the tarsocrural joint and the medial aspect of the talus. Arthrotomy for flap removal and curettage was performed on 11 joints; 6 joints did not receive surgery. After a mean period of 34 months following diagnosis, the dogs were examined clinically and the affected joints were radiographed. The degree of lameness, range of motion, and stability of the tarsocrural joint were graded for each limb. Radiographic determinants that were assessed included: width of the medial tarsocrural joint space, medial tarsocrural osteophyte formation, lateral tarsocrural osteophyte formation, caudal tarsocrural osteophyte formation, medial talus osteophyte formation, lateral talus osteophyte formation, intertarsal osteophyte formation, subchondral sclerosis of the distal end of the tibia, presence of joint bodies, and periarticular soft-tissue thickness. On the basis of clinical and radiographic evaluations, the surgical procedures described in this report did not modify progression of osteoarthritic changes.     

Clinical, clinicopathologic, pathologic, and toxicologic alterations associated with gossypol toxicosis in feeder lambs

The toxicity of gossypol was studied in 20, 8-week-old feeder lambs that weighed approximately 16 kg. The lambs were allotted to 4 groups (A, B, C, D) and given (orally for 30 days) a daily dosage of gossypol (0, 45, 136, or 409 mg, respectively). Lambs were observed twice daily until they died or were euthanatized on the day the last dose was given. Clinical, electrocardiographic, clinicopathologic, pathologic, and toxicologic findings were recorded. All lambs given 409 mg of gossypol (group D) died before the end of the 30-day study. In this group, clinical signs included sudden death and/or chronic dyspnea syndromes. One group-B lamb had chronic dyspnea, but did not die. Electrocardiographic abnormalities observed in gossypol-treated lambs included increased amplitude of the T wave and decreased duration of the ST segment. Clinicopathologic alterations in group-D lambs included high serum total lactate dehydrogenase and lactate dehydrogenase liver-specific isoenzyme activities. Serum total creatine kinase activity decreased markedly in lambs of all groups treated with gossypol. Hemoglobinuria was detected in 2 group-D lambs. The average daily weight gain was remarkably consistent in lambs of all groups, except in 1 lamb each of groups D and B. Lambs were necropsied when they died or on day 30 of the study. The heart of gossypol-treated lambs weighted more than did that of untreated (control group A) lambs.(ABSTRACT TRUNCATED AT 250 WORDS)     

Muscle protein turnover and tenderness in broiler chickens fed cimaterol

To investigate the impact of cimaterol (CIM) on muscle protein turnover, carcass and muscle composition, muscle cathepsin B + L activity and meat tenderness, 21-d-old broiler chickens (n = 88) were assigned to dietary treatments of either 0 or 1 ppm CIM. Fractional synthesis rates (FSR), fractional accretion rates (FAR), proximate composition and collagen content were determined in the breast muscle (BM); pectoralis major) and a group of leg muscles (LM; gastrocnemius and peroneous longus) from groups of six birds per treatment within each of two time periods (age = 38 or 56 d). Whole body composition, serum hydroxyproline content and BM cathepsin B + L activity also were measured. Fractional degradation rates (FDR) were calculated as the difference between FSR and FAR. Feeding CIM increased (P less than .01) whole body protein content. Weights of LM and percentage of body weight as BM and LM were increased (P less than .05) when CIM was included in the diet. Although FSR was not significantly reduced by CIM feeding it decreased (P less than .05) with increasing age. Due to decreases in FAR, FDR thereby was reduced by CIM 31.5% and 11.9% in BM and 38.2% and 37.4% in LM at 38 d and 56 d of age, respectively. Cathepsin B + L activities also were reduced 33.6% (P less than .01) and shear forces were increased by 41% (P less than .05) by CIM feeding. For chickens fed CIM, the correlation between cathepsin B + L activity and shear force was -.63 (P less than .01). Feeding CIM improved carcass leanness and muscling due to reductions in FDR and proteolytic enzyme activity. Feeding CIM also reduced meat tenderness.     

NONGRAFTED AND GRAFTED OSTEOTOMIES OF PROXIMAL SESAMOID BONES OF THE HORSE

A radiographic study of healing patterns of nongrafted and grafted basilar osteotomies of proximal sesamoid bones in 14 horses was performed. Osteotomies were created in one proximal sesamoid bone of each fromt leg. One was treated by an autogenous rib graft, and the other was left nongrafted. Wedge-shaped cortical bone, corticocancellous bone with multiple drill holes, and chips of cancellous hbone were used as autogenous grafts. Presurgical, surgical, and postsurgical radiographic examinations were performed. The longest follow-up period was 40 weeks. High detail radiography of 3-mm bone sections and microangiography were also perofromed. Radiographic interpretation of lack of bone healing was erroneous in approximately one-half of the cases. Lack of an external bridging callus was incorrectly interpreted as lack of bony union. If noted, periosteal new bone formation failed to develop into a pattern of bridging callus. Radiographs did not permiit detection of the osteotomy line entering the articular surface or displacement of distal fragments. From angiography obtained ten weeks after surgery, the pattern of blood supply was similar in nontreated and grafted sesamoid bones. Microangiography showed rich vascularization of the cancellous graft and callus, reflecting good healing activity, whitle vascularization of the osteotomy site was absent in the nontreated osteotomies.     

Book review

Disinfection, Sterilization and Preservation, edited by Seymour S. Block. 1983. 1053 pages. 3rd Edition. Philadelphia, Lea and Febiger. Price $87.50. ISBN 0 8121 0863 9.     

THE RHESUS MONKEY

Transbronchoscopic inoculation of five serotypes of Streptococcus pneumoniae was used to produce pneumonia in five rhesus monkeys. The development and resolution of the pneumonia were followed radiographically and clinically. The initial inoculation determined the lung lobes that would become involved. The acute state was accompanied by a febrile response, leukocytosis, and bacteremia. Resolution of the pneumonia occurred in six weeks. The radiographic features of spontaneous streptococcal pneumonia in rhesus monkeys were similar but not identical to those found in man. However, extension to other lobes, mediastinal lymphadenopathy, and extensive pleural effusion, as often noted in the human, were not identified. The rhesus monkey is thought to be a good animal model for the radiographic evaluation of streptococcal pneumonia.     

Effect of estrogen inhibitors on conceptus estrogen synthesis and development in the gilt

Two estrogen antagonists (keoxifene and clomiphene) and two aromatase inhibitors (LY56110 and 4-hydroxyandrostenedione, 4-OHA) were utilized to determine the role of conceptus estrogen in trophoblastic elongation and maintenance of pregnancy in the pig. Pregnant gilts were unilaterally hysterectomized on day 10.5, and infused via a uterine arterial catheter with 200 mg of keoxifene or vehicle. The remaining uterine horn was removed based on time estimated for conceptus elongation. In a second study, pregnant gilts were injected daily with 200 mg (i.m.) of clomiphene or vehicle during pregnancy (days 10-16) and hysterectomized on day 30. A third study assessed in vitro aromatase inhibition by 4-OHA and LY56110 using trophoblastic microsomes incubated with [1 beta, 2 beta-3H]-androstenedione for 6 hr. In a fourth study, in vivo inhibition of aromatase activity was determined. For this study pregnant gilts, unilaterally hysterectomized on day 10.5, received either 4-OHA, LY56110, or vehicle. Conceptus development and uterine estrogens were quantified. None of the estrogen antagonists and aromatase inhibitors interferred with conceptus elongation. Uterine protein, calcium and acid phosphatase were similar (P greater than .10) between keoxifene- and vehicle-treated gilts. Embryonic survival of clomiphene- and vehicle-treated gilts was similar (91.5 vs 87.4%). In vitro, 4-OHA and LY56110 had 50% inhibitory concentrations of 0.1 microM and 13 nM. Treatment of gilts with 4-OHA reduced total estrogens in uterine flushings by 57% (P less than .02), whereas treatment with LY56110 did not significantly lower total estrogen content in uterine flushings. Estrogen antagonists were not effective in blocking conceptus elongation and maintenance of pregnancy. Although estrogen synthesis can be inhibited in vitro, dosages of aromatase inhibitors used were not totally effective in vivo.