45,X/46,X dic (Y) mosaicism in a phenotypic male.

Cytogenetic analysis, confirmed by in situ hybridisation studies, showed a mosaic 45,X/46,X dic (Y) (q12) karyotype in a 14 year old boy who was initially diagnosed as having Noonan''s syndrome. He made an early response to recombinant growth hormone; this suggests that this treatment may improve final height.     

Novel pluripotential neural progenitor lines exhibiting rapid controlled differentiation to neurotransmitter receptor‐expressing neurons and glia

The immortalization of progenitor cells from embryonic murine hippocampus using oncogene‐carrying retroviral vectors is described. Use of a vector encoding the oncogene v‐myc results in lines of nestin‐positive progenitor cells. Limited differentiation ensues if the cells are cultured in the presence of dibutyryl cyclic adenosine monophosphate. In contrast, use of a vector in which the extracellular portion of the epidermal growth factor (EGF) receptor is fused to the neu tyrosine kinase generates lines of pluripotential nestin‐positive progenitor cells, which differentiate upon withdrawal of EGF into neurons and glia. Differentiated neurons expressing action potentials and neurotransmitter receptors make up a high proportion of the cells. These cell lines are useful tools to investigate the characteristics of differentiating neurons and glia, as well as to screen neuroactive drugs. This work has been reported in preliminary form as an abstract (1996 Society for Neuroscience Abstract, #606.20, p. 1537).     

"Schnyder's rule" of heritability of skin tumors and its extension to cases of segmental presentation

"Schnyder's rule" states that multiple tumours of the skin are dominantly inherited, whereas solitary tumours of the same histological type are noninherited. This rule may be extended to cover segmental cases representing somatic mutations.     

Unusual cardiac papillary fibroelastoma in the right ventricular outflow tract.

Cardiac papillary fibroelastoma (CPF) is the second most common benign neoplasm of the heart. This study describes the case of an 81-year-old man who was admitted to the hospital for severe vertigo and in whom a tumor at the right ventricular outflow tract (RVOT) was identified incidentally during echocardiography. The CPF was excised smoothly following the confirmation of its position by computed tomography. The comprehensive pathologic findings of CPF were reviewed. Detailed immunohistochemical analyses of CD34 and factor VIII-related antigen were performed on the covering endocardial cells. The unique chondroid metaplasia of fibrous tissue in this CPF has never been reported. This work is the first to present an unusual CPF at the RVOT with reactive process of fibrous connective tissue.     

Effects of x-ray and CT image enhancements on the robustness and accuracy of a rigid 3D/2D image registration

A rigid body three-dimensional/two-dimensional (3D/2D) registration method has been implemented using mutual information, gradient ascent, and 3D texturemap-based digitally reconstructed radiographs. Nine combinations of commonly used x-ray and computed tomography (CT) image enhancement methods, including window leveling, histogram equalization, and adaptive histogram equalization, were examined to assess their effects on accuracy and robustness of the registration method. From a set of experiments using an anthropomorphic chest phantom, we were able to draw several conclusions. First, the CT and x-ray preprocessing combination with the widest attraction range was the one that linearly stretched the histograms onto the entire display range on both CT and x-ray images. The average attraction ranges of this combination were 71.3 mm and 61.3 deg in the translation and rotation dimensions, respectively, and the average errors were 0.12 deg and 0.47 mm. Second, the combination of the CT image with tissue and bone information and the x-ray images with adaptive histogram equalization also showed subvoxel accuracy, especially the best in the translation dimensions. However, its attraction ranges were the smallest among the examined combinations (on average 36 mm and 19 deg). Last the bone-only information on the CT image did not show convergency property to the correct registration.