Bone lesions, distribution

Fig. 4. Distribution of bone lesions in GD. Black most frequently involved. Hatched less frequently involved. Dotted rarely involved...

The distribution of the element is similar to that of calcium which means that 99% of the body burden is deposited in bone [44]. Within the dialysis population, bone strontium levels were found to be significantly higher in subjects with osteomalacia as compared to this presenting the other types of renal osteodystrophy [45]. A causal, dose-dependent role of strontium in the development of this bone disease has been established in a chronic renal failure ratmodel [46,47]. Moreover the bone osteomalacic lesions were found to be reversible after withdrawal of strontium [9,48]. 

Often there is no good clinical test available to determine the exact type of hepatic lesion, short of liver biopsy. There are certain patterns of enzyme elevation that have been identified and can be helpful (Table 38-3). ° The specificity of any serum enzyme depends on the distribution of that enzyme in the body. Alkaline phosphatase is found in the bile duct epithelium, bone, and intestinal and kidney cells. 5-Nucleotidase is more specific for hepatic disease than alkaline phosphatase, because most of the body s store of 5 -nucleotidase is in the liver. Glutamate dehydrogenase is a good indicator of centrolobular necrosis because it is found primarily in centrolobular mitochondria. Most hepatic cells have extremely high concentrations of transaminases. Aspartate aminotransferase (AST) and alanine aminotransferase (ALT) are commonly measured. Because of their high concentrations and easy liberation from the hepato-cyte cytoplasm, AST and ALT are very sensitive indicators of necrotic lesions within the liver. After an acute hepatic lesion is established, it may take weeks for these concentrations to return to normal. ... 

Nonneoplastic microscopic changes associated with treatment with isotretinoin consisted of focal fibrosis and focal chronic inflammation in the heart, adrenal medullary hyperplasia, arteritis, arterial calcification, focal tissue calcification, and focal osteolysis of the bone. The severity and distribution of these lesions were dose-related. 

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