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Background: Failure of palatal shelf fusion at the precise gestational time point when shelf elevation and migration normally occur results in clefting. The present study defined the mechanism of clefting in the congenital caprine model by evaluating the temporal sequence of palatal shelf fusion. Methods: Six Spanish-type goats pregnant with twins were gavaged for 10 days (gestational days 32 to 41) with anabasine. Goats were examined with ultrasound throughout this period to assess fetal movement and evaluated histologically. Twelve untreated, unclefted fetuses served as controls. Results: After anabasine induction, real-time ultrasound confirmed a dramatic decrease in fetal movement. Hyperflexion of the neck occurred throughout the experimental period compared with control fetuses, in which spontaneous neck movements occurred. Histologic evaluation of the induced fetuses demonstrated the tongue wedged between the palatal shelves throughout the period of fusion. The shelves remained vertically oriented without elevation, ultimately resulting in clefting. The unclefted, control group demonstrated progressive elevation and migration of the palatal shelves between gestational days 38 and 40, with contact and fusion of the medial edge epithelia in the midline. Conclusions: Palatal clefting in the congenital caprine model occurred concomitant with reduced fetal movement. Resultant neck hyperflexion causes the tongue to obstruct medial migration of the palatal shelves and fusion, whereas the shelves themselves are either directly prevented from elevation secondary to anabasine impairment or indirectly secondary to the obstructing tongue. Although the molecular mechanism for the teratogenic effects of anabasine remains elusive, the authors have demonstrated an association between reduced fetal movement and palatal clefting in their congenital caprine model.

The key to achieving an excellent result following rhinoplasty lies in a strong fundamental knowledge of nasal anatomy. The purpose of this study was to analyze the anatomic and histologic relationship of the nose to the alar-facial crease. Fifteen cadaver noses were dissected and a total of thirty lower lateral cartilages were measured. Two fresh cadaver noses were fixed in neutral buffer formalin and embedded in paraffin. They were then sectioned into 6-mu coronal and sagittal sections and stained with hematoxylin and eosin, Eosin von Geison, and safranin to evaluate for collagen, elastin and muscle, respectively. Measurements of the lower lateral cartilages showed the average lateral crural height was 23.5 mm (+/- 2.5 mm), lateral crus width was 11.7 mm (+/- 1.5 mm), lateral domal width was 5.7 mm (+/- 0.9 mm), and intercrural distance was 20.2 mm (+/- 3.2 mm). No statistical differences were noted between male and female cadaver measurements. Histologic sections showed the area of the alar-facial crease to have a greater quantity of elastin fibers compared with muscle, collagen, or cartilage. These elastin fibers were predominantly orientated vertically (anterior-posterior) rather than horizontally (cephalo-caudad). This study demonstrates a higher ratio of elastin to collagen fibers in the region of the alar-facial crease.

Poly(urethane-imide)s (PUI)s were prepared by the intermolecular Diels-Alder (DA)reaction of 4-methyl-1,3-phenylene-bis(2-furanylmethylthioethylcarbamate) (MPFTC) with various bismaleimides. The DA reaction was carried out in 1,4-dioxane as a solvent as well as in bulk, followed by aromatization of tetrahydrophthalimide intermediates in the presence of acetic anhydride. All the polymers were characterized by elemental analysis, IR spectral studies and thermogravimetry. The PUIs exhibit moderate thermal stability. MPFTC and bismaleimides were polymerized (at 145 - 10°C) by an "in situ" DA intermolecular reaction into moderately thermally stable PUIs glass-fiber composite (i.e., laminates) and were characterized by their chemical resistance and mechanical properties.