oxytetracycline--anhydrous and Osteoporosis

We measured the individual lengths of fluorescent labels on the three subdivisions of the endosteal envelope in iliac bone biopsy specimens produced by the administration of both oxytetracycline and demethylchlortetracycline. Fifty-one healthy subjects and 53 patients with postmenopausal osteoporosis were labeled in the stated order, and 8 osteopenic patients were labeled in the reverse order. Whatever the order of administration, the demethylchlortetracycline label was longer than the oxytetracycline label. We conclude: (1) the difference in label lengths reflects a difference between the two compounds in some intrinsic property, whether physical, chemical, or pharmacokinetic. (2) If the calculation of extent of mineralizing surface is based on the mean length of the two labels, a suitable correction should be applied to the shorter label; alternatively, the length of the longer label alone should be used. (3) Unlabeled osteoid not due to label escape probably results from slow terminal mineralization after cessation of matrix synthesis during which too few tetracycline molecules are incorporated to exceed the threshold for visible fluorescence, rather than from the temporary interruption of mineralization followed by its resumption.

Topics: Adult; Aged; Bone and Bones; Bone Density; Demeclocycline; Female; Fluorescent Dyes; Humans; Microscopy, Fluorescence; Middle Aged; Minerals; Osteogenesis; Osteoporosis; Oxytetracycline

The acute effects of immobilization on cortical and trabecular bone formation were studied in juvenile male rhesus monkeys (Macaca mulatta). Four animals were immobilized for two weeks by application of total body casts. Two control monkeys were housed in separate metabolic cages under similar environmental and dietary conditions. Tetracycline derivatives were administered on three separate occasions to label sites of bone formation. The tetracycline-labeling frequency and mineral apposition rate of osteons and trabecular bone surfaces in the humerus and femur were determined. The inhibition of bone formation induced by immobilization was more pronounced in trabecular bone. Immobilized monkeys exhibited a moderate, but statistically nonsignificant, reduction in the percentage of osteons forming bone. Conversely, the dramatic decline in the percentage of trabecular surfaces undergoing bone formation in immobilized monkeys was found to be highly significant. The diminished rate of mineral apposition in osteons suggested that osteoblastic activity was impaired in cortical bone during immobilization. The mineral apposition rate in trabecular bone could not be determined reliably due to minimal tetracycline deposition, which indicated that osteoblastic activity and/or recruitment almost ceased in the metaphyseal tissue of immobilized monkeys.

Topics: Animals; Bone and Bones; Bone Regeneration; Bone Resorption; Demeclocycline; Femur; Humerus; Immobilization; Macaca mulatta; Male; Minerals; Osteoblasts; Osteoporosis; Oxytetracycline; Tetracycline

Topics: Anemia, Hypochromic; Arthritis; Diarrhea; Duodenum; Femur Head; Hip Joint; Humans; Intestinal Mucosa; Lymph Nodes; Male; Middle Aged; Osteoporosis; Oxytetracycline; Radiography; Whipple Disease

Topics: Animals; Bone and Bones; Dose-Response Relationship, Drug; Methods; Microscopy, Fluorescence; Osteoporosis; Oxytetracycline; Parathyroid Hormone; Rats; Tetracycline; Time Factors; Tissue Preservation