Combined multiphoton imaging and biaxial tissue extension for quantitative analysis of geometric fiber organization in human reticular dermis.

The geometric organization of collagen fibers in human reticular dermis and its relationship to that of elastic fibers remain unclear. The tight packing and complex intertwining of dermal collagen fibers hinder accurate analysis of fiber orientation. We hypothesized that combined multiphoton microscopy and biaxial extension could overcome this issue. Continuous observation of fresh dermal sheets under biaxial extension revealed that the geometry of the elastic fiber network is maintained during expansion. Full-thickness human thigh skin samples were biaxially extended and cleared to visualize the entire reticular dermis. Throughout the dermis, collagen fibers straightened with increased inter-fiber spaces, making them more clearly identifiable after extension. The distribution of collagen fibers was evaluated with compilation of local orientation data. Two or three modes were confirmed in all superficial reticular layer samples. A high degree of local similarities in the direction of collagen and elastic fibers was observed. More than 80% of fibers had directional differences of ≤15°, regardless of layer. Understanding the geometric organization of fibers in the reticular dermis improves the understanding of mechanisms underlying the pliability of human skin. Combined multiphoton imaging and biaxial extension provides a research tool for studying the fibrous microarchitecture of the skin.

Thenar Dysplasia in Radial Polydactyly Depends on the Level of Bifurcation.

BACKGROUND: Little is known about thenar dysplasia in radial polydactyly, other than that thenar hypoplasia occasionally occurs in radial polydactyly with triphalangism. In particular, the phenotype and level of duplication associated with thenar dysplasia remain unclear. METHODS: The abductor pollicis brevis and flexor pollicis brevis muscles were visualized using three-dimensional ultrasound, and their horizontal geometry was assessed using a biaxial level classification system. Subjects were categorized into three phenotypes according to the developmental condition of the radial thumb. The relationship between the level of distribution of the muscles and the level of the bifurcation of the radial thumb was investigated. RESULTS: Nineteen patients with radial polydactyly without triphalangism were included. There were 10 patients with the nonfloating type, three with the floating type, and six with the rudimentary type. All patients with bifurcation at or more distal to the metacarpophalangeal joint had normal thenar muscle distribution, but the muscles in patients with bifurcation at or more proximal to the level of the metacarpals were confined, regardless of phenotype. The level of muscle distribution was strongly correlated with the level of the bifurcation of the radial thumb. CONCLUSIONS: These findings suggest that formation of the thenar muscles in the longitudinal direction in radial polydactyly might depend on the level of bifurcation of the radial thumb. The presence of thenar dysplasia even in floating-type or rudimentary-type duplications is of clinical and etiologic importance.

Aryl-Allene Cyclization via a Hg(OTf)2-Catalytic Pathway.

Hg(OTf)2-catalyzed aryl-allene cyclization accompanied by formation of a quaternary carbon center has been realized. Deuterium-labeling experiments and computational modeling were used to propose a novel catalytic pathway involving direct H-transfer from the aromatic ring to the vinyl mercury moiety followed by mercury 1,2-migration.

Three-dimensional ultrasonography for visualization of muscular anomalies in type VI and VII radial polydactyly.

OBJECTIVE: To describe a technique and its clinical applications of three-dimensional ultrasonography to type VI and VII radial polydactyly for identification of potential muscular anomalies. MATERIALS AND METHODS: Ultrasonographic examinations were performed at an out-patient department without sedation or an operative room prior to surgery. The palm was scanned in the transverse direction using a 18-MHz linear transducer under speed regulation at 3 mm/s. Sequential images acquired at 0.2 mm intervals were converted into volume data. After validation of the technique, patients with a radial polydactyly in association with triphalangism (type VII) or with polydactylies of metacarpal duplication (type VI) were included for the examination. RESULTS: Five hands of five patients, one with type VI and four with type VII, were included the study. All the patients were male and the ages at examination ranged from 7 months to 2 years. Of the five patients, four examinations were performed at an out-patient department without sedation and one was under anesthesia just prior to surgery. The muscular abnormalities identified were mal-positions of the thenar muscles in a type VI case and a deficiency of the abductor pollicis brevis muscle in a type VII case with a delta phalanx in the ulnar part. CONCLUSION: Three-dimensional ultrasound technique could be an aid to plan strategies in radial polydactyly if intrinsic muscular anomalies are suspected to be involved.

Malignant peripheral nerve sheath tumor with fibroblastic differentiation in a patient with neurofibromatosis type 1: imprint cytological findings.

BACKGROUND: Malignant peripheral nerve sheath tumor (MPNST) is a heterogeneous group of neoplasms that shows divergent differentiation potential, and the cytological findings are largely nonspecific. There are no previous reports specifically alluding to the cytological findings of MPNST showing fibroblastic differentiation (fibroblastic MPNST). CASE: A 59-year-old woman with neurofibromatosis type 1 developed a rapidly enlarging tumor on the scalp. A metastatic lesion in the ileum was examined cytologically. Irregularly shaped clusters of spindle cells with wavy or buckled nuclei and fibrillary cytoplasm were found as well as many similar isolated cells. Histopathologically, the tumor showed a spindle cell sarcomatous appearance typical of MPNST. Immunohistochemically, the tumor cells were negative for S-100 protein and epithelial membrane antigen but immunoreactive for vimentin, CD10 and CD34. Ultrastructurally, the tumor cells were not invested by the basal lamina and had abundant rough-surfaced endoplasmic reticulum and a subplasmalemmal accumulation of microfilaments with dense patches. These immunohistochemical and ultrastructural findings were consistent with fibroblastic or myofibroblastic differentiation. CONCLUSION: Although there are no cytological findings specific for fibroblastic MPNST, the wide spectrum of differentiation in MPNST should be kept in mind during cytological examination of soft tissue sarcomas.