Assessing bones

Bone maturation Use cautiously in healthy males with delayed puberty. Monitor bone maturation by assessing bone age of the wrist and hand every 6 months. Carcinogenesis There are rare reports of hepatocellular carcinoma in patients receiving long-term therapy with androgens in high doses. 

A. Paget s disease is often asymptomatic and picked up on plain bone films. Patients with Paget s disease should have their serum calcium level determined to make sure that they are not hypercalcemic from excessive bone resorption, their serum alkaline phosphatase measured as a marker of new bone formation, a bone scan to determine whether other bones are involved, and a 24-hour urinary hy-droxyproUne measurement to assess bone resorption. The patient who has minimal involvement and is biochemically normal does not need pharmacological therapy. No studies indicate that early treatment slows progression in individuals with the more severe form of this disorder. 

Studies of the effects of inhaled glucocorticoids have used biochemical markers of bone function and imaging techniques to assess bone mineral density. Some of the biochemical markers are summarized in Table 1. Initial, short-term studies caused concern about the effect of inhaled glucocorticoids on bone metabolism. 

Bone markers are used to assess bone turnover (resorption or formation) in patients with osteoporosis. This testing is useful for identifying osteoporotic individuals with elevated bone resorption and for predicting and assessing the response to therapy. Markers of bone resorption include collagen cross-finks (N telopeptide, deoxypyridinoline, or C-telopeptide). Because bone resorption and formation are coupled, markers of bone formation (BAP and serum osteo-... 

Because type 1 collagen is also the major matrix of several other tissues, collagen propeptides are not as sensitive or specific for bone formation as osteocalcin or BAP. Measurement of procoUagen peptides may be helpful for assessing bone formation in patients treated with 1,25-dihydroxyvitamin D or in patients with abnormal concentrations of this hormone when osteocalcin and BAP may be misleading. 

Bonde M, Fledelius C, Qvist P, Christiansen C. Coated-tube radioimmunoassay for C-telopeptides of type I collagen to assess bone resorption. Clin Chem 1996 42 1639-44. 

Before transplant, BMD should be measured and vitamin D and gonadal status assessed. Bone-healthy lifestyle changes and therapy should be instituted as needed (see Fig. 88-4) and hypogonadism corrected before and after transplant. Intermittent pamidronate has decreased bone loss in most transplant recipients." Use of bisphosphonates in children and when creatinine clearance is less than 30 mL/min is being explored. Glucocorticoid doses should be... 

As noted earlier, transferrin saturation (i.e., serum iron level divided by the TIBC) is also useful in assessing IDA. Low values likely indicate IDA, although low serum transferrin saturation values may also be present in inflammatory disorders. Fortunately, the TIBC usually helps to differentiate the diagnosis in these patients a TIBC greater than 400 mcg/dL suggests IDA, whereas values below 200 mcg/dL usually represent inflammatory disease. With continued progression of IDA, anisocytosis occurs and poikilocytosis develops, as seen on peripheral smear and indicated by increased RDW. In rare cases, a bone marrow examination can be performed to assess bone marrow iron stores. Bone marrow examination reveals absent iron stores in IDA. Documenation of decreased hemosiderin can confirm the diagnosis of IDA. In microcytic anemias due to all other causes, iron stores are detectable. 

X Rays. The most common application of planar X-ray imaging is in orthopedics, where it is used to assess bone integrity and detect fractures and breaks. Bone absorbs X-ray photons readily and therefore appears bright on X-ray film. In addition to planar X-ray imaging, there are a number of commonly used X-ray-based imaging modalities. Fluoroscopy is an imaging procedure that allows doctors to obtain... 

Lin, Y., Hillegonds, D., Gertz, E., Van Loan, M., and Vogel, (. (2004) Protocol for assessing bone health in hiunans by tracing long-lived Ca isotope in luine serum and saliva samples. Anal. Biochem.. 332, 193-195. 

Early Chemist Paracelsus 4 Toxicology and Risk-Benefit Assessment Bone Density 47 Breathing Mixtures 61 Variation in Body Temperature 67 Losing and Gaining Weight 72 Steam Burns 80 Toxicity of Mercury 99 Elements Essential to Health 103 Biological Reactions to UV Light 119 Radiation and Food 146 Brachytherapy 154... 

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