ABSTRACT NC-eob mice are mutants having open eyelids at birth. Previous studies have revealed that this defect is related to the absence of epidermal differentiation at the tip of the developing eyelids on gestation day (GD) 16, and that maternal treatment with cortisone acetate (CA), a glucocorticoid compound, which has an ability to accelerate epidermal differentiation, is not effective against the epithelium in NC-eob fetuses although the eyelid growth is slightly enhanced. In this study, transverse sections of the eyelids of NC-eob fetuses on GDs 14 and 15 were evaluated immunohistochemically for glucocorticoid receptors (GRs) by using coiso- genic NC fetuses as a control. For comparison, GRs in the palate were also investigated. On GD 14, the GR density in both the epithelium and mesenchyme of the eyelids was comparable between NC-eob and NC fetuses. On GD 15, on the other hand, the GR density in the mesenchyme was significantly lower in NC-eob than in NC, while no such change was found in the epithelium. The GR density in the palate of NC-eob fetuses was comparable to that of NC fetuses in both the epithelium and mesenchyme on any of the gestation days examined. These results suggest that the low density of GR in the eyelid mesenchyme of NC-eob fetuses on GD 15 may be one of the reasons for the insufficient development of the eyelids after treatment of their mothers with CA.
ABSTRACT In classic human embryology, one of the most important techniques to observe embryonic structures three-dimensionally (3-D) was to reconstruct embryos or their parts using wax plate models from serial histological sections. However, wax plate reconstruction does not allow observation of internal structures and lumens unless the models are cut after reconstruction. The development of computer graphics has enabled us to reconstruct various biologic structures on the viewing screen and to manipulate the computer images as freely as we desire. Nevertheless, until now computer reconstruction has not been used frequently to study human organogenesis. We reviewed and photographed serial histological sections of early human embryos, projected these photographed slides onto a screen and traced the outlines of specific structures under study on a digitizing pad that was interfaced with a 16 bit computer. The digitized images were combined using a software for 3-D reconstruction. With this technique, we were able to visualize the anatomical localization and interrelation of various structures inside the human head during the embryonic period. The 3-D reconstruction technique should be of potential use for the study of normal and abnormal morphogenesis.
ABSTRACT We examined two Japanese patients with hypochondroplasia (HCH) whether they had mutations in the gene (FGFR3) encoding the fibroblast growth factor receptor 3 using polymerase chain reaction (PCR) coupled with direct sequencing. In both of our patients, a C+A transversion was detected in nucleotide 1659, predicting a substitution of asparagine for lysine at position 540 of the mature protein which corresponds a part of the tyrosine kinase 1 (TK1) domain. Our results suggest that a common mutation specific for HCH in the TK1 domain of FGFR3 exists among Japanese patients with HCH.