RESUMO
The objectives were to determine the nutrient composition and variation in eight cuts of bison meat in bulls and heifers and identify nutrient relationships in the clod and sirloin by principal component analysis. The nutrients analyzed were: energy, protein, total fat, saturated fat, monounsaturated fat, polyunsaturated fat, transfat, cholesterol, vitamin A, Ca, Fe, Na and moisture. Differences were observed in fat components between cuts and bulls had higher (P<0.05) amounts of total, saturated, monounsaturated and polyunsaturated fat in the blade compared to the other cuts. The sirloins had less (P<0.05) cholesterol than all the other cuts in bulls and the clod in heifers. Fat varied more than protein and moisture in all cuts. Four principal components (PC) accounted for 63.9% of the total variation of the nutrient composition. Total, monounsaturated and saturated fats were in PC1 and cholesterol in PC2 showing that cholesterol is independent of other fats. If dietary alterations elicit changes in bison meat fatty acid profiles, it may be possible to reduce cholesterol independent of total, monounsaturated or saturated fat.
RESUMO
After successful trabeculectomy patients often complain of reduction in vision even after several months. Amongst other factors, corneal astigmatism appears to be altered. A pilot study measuring, pre- and post-operative corneal topography indicated three types of astigmatic change: some patients develop a relative superior corneal steepening, others a superior flattening and yet others complex regional changes that do not conform to either of these patterns. The present study was designed to evaluate further these patterns of variation in corneal curvature and to look for corresponding refractive and keratometry changes. Twenty-nine patients admitted for trabeculectomy had pre-operative assessment of subjective and automated refraction, manual keratometry and corneal topography from which simulated keratometry values were calculated. A standard trabeculectomy procedure was performed and post-operative measurements of the same parameters were taken at 1 and 3 months after surgery. Similar patterns of corneal topographic change to those found in our pilot study were noted. In both the superior steepening and superior flattening groups there was an increase in vertical keratometry and a shift towards 'with-the-rule' astigmatism. Furthermore a 1 year analysis of 13 patients from our pilot study indicated that the topographic changes lasted for at least 12 months after surgery. We conclude that computer-assisted corneal topography reveals complex regional changes in corneal curvature that are not readily detected from alterations in refraction or keratometry. These changes are sufficiently great to have a significant effect on visual function in some patients.
