Hypoplastic tibiae with postaxial polysyndactyly: a new dominant syndrome?

A five year old boy is reported with hypoplastic, bowed tibiae and postaxial polysyndactyly. Sixteen relatives of both sexes in four generations either have bilateral syndactyly or postaxial polydactyly or both. The nature of the condition and the possible mode of inheritance are discussed.     

Video reconstructions in dentistry

Authors – Farag AA, Eid A Objectives – To present two practical techniques for three‐dimensional (3D) modeling of the human jaw from a sequence of intra‐oral images. Design – A data acquisition system consists of: 3D digitizing arm, CCD camera and a laser projector in addition to a software module of two 3D modeling techniques; shape from shading (SFS) and space carving (SC). Setting and sample population – Several experiments have been conducted on a sample of students at the Computer Vision and Image Processing (CVIP) Laboratory at the University of Louisville, Louisville, KY. Other experiments were performed on solid models of human jaw. Experimental variable – The SFS technique, using perspective projection and camera calibration, extracts the 3D information from a sequence of two‐dimensional images of the jaw. Data fusion of range data and 3D registration techniques develop the complete jaw model. The SC approach is implemented on a sequence of calibrated images. On the two reconstructions, we fit a mesh model to the data, in order to create a solid 3D model. Outcome measure – The accuracy of the reconstructed 3D model of human jaw is calculated based on the measurements on real jaws. Results – The SFS‐based technique seems to provide more faithful information about the shape of the tooth tops. However, the SC algorithm successfully reconstructed 3D models of the human jaw with sub‐millimeter accuracy, which is as accurate as (or even better than) the first technique without using any range measurements or laser projectors. The average error in distance calculation was found to be 0.74 mm, which is an acceptable resolution for many orthodontics and maxillofacial applications. Conclusion – Accurate 3D reconstruction of the human jaw enables many orthodontics and dental imaging research findings to be applied directly to a digital jaw model – not to a cast – using computer vision and medical imaging tools.     

Effects of quillaja saponin (Quillaja saponaria) on early embryonic zebrafish (Danio rerio) development

Although much attention has focused on environmental contamination by heavy metals, pesticides, and polychlorinated biphenyls, potential deleterious effects of naturally occurring organic compounds have received much less consideration. Saponins, which are glycosides found in many plants, are important, environmentally ubiquitous organic compounds. Saponins have both beneficial and deleterious effects in adults, but little is known about how saponins effect early vertebrate embryonic development. The authors tested the toxicity of quillaja saponin using a zebrafish embryo assay. Quillaja saponin, extracted from bark of the tree, Quillaja saponaria, is a common foaming agent used in foods and beverages. At 6 h post fertilization, zebrafish embryos were exposed to five concentrations (0 [negative control], 1, 5, 10 or 20 micro g) of quillaja saponin per milliliter of medium. Zebrafish embryos exposed to 2% ethanol were positive controls (100% embryonic death). Embryos were assessed at 30, 54, and 72 h post fertilization for changes in embryonic development, mortality, time of hatching, and morphological deformities. Embryos exposed to 1 and 5 micro g saponin were healthy, showed no obvious deformities, but exhibited shrinkage of the chorion. Hatching time for zebrafish embryos exposed to 1 and 5 micro g/ml saponin decreased by 18 h compared to unexposed embryos. Zebrafish embryos treated with 5 micro g/ml saponin responded less to touch than embryos treated with 1 micro g/ml saponin or controls. Zebrafish embryos exposed to more than 5 micro g/ml saponin exhibited 100% embryonic mortality. These results indicate that exposure to 5 micro g/ml or less of quillaja saponin acts as a growth promoter, whereas concentrations of 10 micro g/ml or greater are lethal.