Musculoskeletal Key

ADULT OSTEOMALACIA Clinical Manifestations. The diagnosis of adult osteomalacia (see Plate 3-14) may be difficult to establish because the changes may be considerably more subtle than those seen in childhood…

Vitamin D has receptors throughout many tissues and acts as both an endocrine as well as an autocrine/paracrine hormone. The endocrine properties have direct effects on bone and muscle tissue…

CHILDHOOD RICKETS Clinical Manifestations. In severe childhood rickets (see Plate 3-13), growth is impaired and height is generally below the third quartile. However, unless there is concurrent severe nutritional disturbance,…

The causes of rachitic and osteomalacic syndromes are numerous and include a variety of genetic errors, nutritional abnormalities, metabolic disorders, and chronic renal diseases. Quite independent of cause, the clinical…

In summary, the advent of totally automated immunometric I-PTH assays has led to improved accurate clinical discrimination of parathyroid disorders and has provided a tool to measure PTH levels in…

Measurement of biologically active intact PTH is essential for accurate clinical assessment. Today most laboratories use commercially available U.S. Food and Drug Administration (FDA)–approved two sites or sandwich immunometric assays…

In PHP type 1, cyclic AMP is not synthesized in response to PTH, because of a deficiency of the coupling protein Gαs. As a result, little cyclic AMP is produced…

PTH produces its effects on target cells by stimulating the synthesis of second messengers, most notably cyclic adenosine monophosphate (cyclic AMP) by the enzyme adenylate cyclase (see Plate 3-9). This…

PTH activates its target cells by increasing the activity of adenylyl cyclase, thereby increasing cellular levels of cyclic AMP. Cyclic AMP activates a cascade of proteins that produces the physiologic…