Muscle has long been recognized as a target tissue for 1,25-dihydroxy-vitamin D3 (1,25[OH]2D3). Evidence of the presence of VDR is provided here, thus supporting the existence of a receptor-mediated mechanism of action of 1,25(OH)2D3. Vitamin D receptor (VDR) expression is evidenced by detection of VDR-mRNA, through reverse transcription and polymerase chain reaction (RT/PCR), in chicken muscle and muscle cells (myoblasts) as well as in a variety of tissues such as intestine, kidney, heart and brain. VDR presence is also demonstrated by Southern blot of PCR products with a specific VDR-cDNA probe and by immunocytochemistry carried out on myoblasts and cardiac myocytes. Localization of VDR is mainly nuclear and more faintly detected in the cytosol.

Computer assisted medical imaging was used to define the spatial dysmorphology of the foot in three patients with Apert syndrome and to correlate that dysmorphology with ambulation and footwear. Thin slice (2 mm), abutting, high resolution axial computed tomography (CT) foot scans were obtained. The CT data were post processed, using Analyze, to generate three-dimensional surface shaded and volumetric reformations. The reformatted images were evaluated by a bone and joint radiologist to identify abnormalities of bone shape, size, and orientation, of joint morphology, and of the foot as a whole. Five consistent findings were observed among the three pairs of feet: (1) anomalous great toes with phalangeal and metatarsal pathology; (2) simple syndactyly of toes 2-5; (3) fusions between metatarsals; (4) tarsal coalitions; and (5) limitations in commercial footwear. One patient underwent bilateral fifth metatarsal wedge osteotomies to facilitate the wearing of shoes. The dysmorphology of the Apert foot is a combination of congenital malformations and postnatal deformations, secondary to progressive synostosis. Prophylactic foot surgery may be indicated in Apert patients to facilitate shoe fitting.

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