The jump behavior of the humeroradial and tarsocrural joints of the horse

Osteoligamentous preparations of the elbow and hock joints of the horse show “jump” behavior when flexed and extended. This behavior is not seen in undissected anatomical specimens or in the live horse. The hypothesis is that energy is stored in the collateral ligaments during the middle range of joint displacement and quickly released nearing full flexion or extension. This energy storage mechanism has the attribute of negative work. In the undissected specimen and the live horse energy is stored in muscles and tendons as well as in the collateral ligaments, and the obvious jump phenomenon is not observed although the principle of negative work still pertains.     

Dysgenesis of the tubal system in an infertile mare karyotype 63,X:64,XY:65,XXY

A Thoroughbred mare, barren during three years at stud, unresponsive to therapy, and not palpably abnormal anatomically was found to have hypoplasia of the uterine tubes after excision at laparotomy. The cause was an unbalanced genotype. The mosaic karyotype, determined on a blood sample, was indispensible in diagnosis and the case extends the potential for cytogenetic prognostic procedures.     

Porcine malignant hyperthermia susceptibility: erythrocytic osmotic fragility

Erythrocyte osmotic fragility was determined in 27 Pietrain swine which were susceptible to malignant hyperthermia (MH), 29 Yorkshire swine which were resistant to MH (controls), and 50 crossbred swine (Pietrain x Yorkshire), half of which were MH susceptible. Halothane challenge tests and blood creatine kinase activity were used as criteria for determining MH susceptibility. Mean values for osmotic fragility of erythrocytes in concentrations of NaCl between 60 and 120 mM were significantly different for the 3 groups (P less than 0.001). Hemolysis (50%) of erythrocytes occurred at NaCl concentrations of 90 mM for Pietrains, 85 mM for crossbreds, and 78 mM for controls. Increased fragility values occurred in 96% of the Pietrains, 3% of the controls, and 42% of crossbred swine that were halothane test-positive, and 58% of halothane test-negative crossbreds (P less than 0.05). The mean time of onset of signs of MH in response to halothane challenge testing was twice as long in the crossbreds as in Pietrains (P less than 0.01). Reticulocyte counts were moderately high in blood samples from both the Pietrains (P less than 0.001) and the crossbreds (P less than 0.05). Of the swine which were tested for erythrocyte selenium-dependent glutathione peroxidase activity, values were within acceptable laboratory limits in 18 of 20 Pietrains, 14 of 14 halothane test-negative crossbreds, and 8 of 8 halothane test-positive crossbreds. In 2 of 20 Pietrains, a 35% deficiency of this enzyme was found. Heinz bodies were not detected in erythrocytes examined from 21 Pietrains, 20 crossbred swine (8 halothane test positives), and 12 controls.(ABSTRACT TRUNCATED AT 250 WORDS)     

OSTEOCHONDROSIS IN THE LATERAL FEMORAL CONDYLES OF A HORSE

Osteochondrosis of the lateral femoral condyles was diagnosed radiographically in an 8-month-old, female Arabian horse, which had been presented with a hindlimb lameness. The diagnosis was confirmed by gross and microscopic pathology. The location of the lesions was considered unusual for osteochondrosis in the horse.