Prospective evaluation of ground reaction forces in dogs undergoing unilateral total hip replacement.

OBJECTIVE: To evaluate clinical and biomechanical gait variables in a group of dogs before and after (for 1 year) total hip replacement. ANIMALS: 16 dogs with degenerative joint disease of the coxofemoral joint secondary to hip dysplasia deemed candidates for total hip replacement. PROCEDURE: Before and at 1, 3, 6, and 12 months after surgery, each dog was trotted over a biomechanical force platform. Vertical force data evaluated for each stance phase of the treated and untreated hind limbs included peak force, impulse, and limb loading and unloading rates. Vertical peak and impulse data were also evaluated for the forelimbs. Measurements analyzed in the craniocaudal axis, divided into braking and propulsion phases, consisted of peak force and associated impulses. Also, orthopedic examination for each dog included subjective scoring for limb lameness at each evaluation period. RESULTS: Most ground reaction forces (GRF) were significantly lower before surgery for the proposed treated, compared with the proposed untreated, limb. This difference between limbs continued through postoperative month 1. Also at 1 month, some treated limb values were significantly lower than preoperative values. By 3 to 6 months, treated limb GRF increased so that no significant difference between limbs could be found. Vertical and craniocaudal propulsion impulse values were significantly higher in the treated than untreated limb from the 6-month evaluation period through the remainder of the study. Braking component of the craniocaudal axes measurements was unchanged throughout the study. CONCLUSIONS: GRF indicated that dogs of this study had significantly increased loading function of the treated hind limb by 6 months after unilateral total hip replacement. Data also indicated that some force was transferred from the untreated to treated hip over the study period. Loading rates also increased over the study period, indicating increased willingness to load the treated hip over time. Craniocaudal axis data indicated no improvement in braking forces with coxofemoral joint replacement, suggesting that the coxofemoral joint with degenerative joint disease did not have altered braking performance at a trotting gait. Comparison of subjective lameness scores and objective GRF indicated that visual grading of coxofemoral joint lameness is limited.

Cytotoxicity of mononuclear cells and vulnerability of hepatocytes in alcoholic fatty liver of baboons.

Mononuclear cell cytotoxicity against autologous, allogeneic and xenogeneic (rabbit) hepatocytes was investigated in nine baboons fed alcohol for 17-21 months and in nine pair-fed controls. All alcohol-fed animals developed fatty liver. Cytotoxicity of mononuclear cells was not observed when rabbit hepatocytes were used as target cells, but mononuclear cells of alcohol-fed baboons were cytotoxic against hepatocytes of both control animals and hepatocytes from alcohol-fed baboons, including the animals' own hepatocytes. Increased vulnerability of hepatocytes of alcohol-fed baboons was also demonstrated since mononuclear cells of both controls and alcohol-fed animals were more cytotoxic against hepatocytes of alcohol-fed baboons than against those of controls. Thus, autologous and heterologous hepatocytes are more sensitive in the baboon than rabbit hepatocytes in demonstrating cytotoxicity already at the stage of fatty liver. Two factors are contributory: mononuclear cells cytotoxicity and vulnerability of hepatocytes.

Biochemical tests for the detection of alcoholism: comparison of plasma alpha-amino-n-butyric acid with other available tests.

The measurement of AANB relative to leucine was found to be a useful biochemical test for the detection of chronic alcohol consumption. This test, in combination with GGTP determinations, provided a sensitive means of detection (81% positive) for chronic alcohol consumption with a minimum of false positive determinations (2%).