Col1a1-cre mediated activation of beta-catenin leads to aberrant dento-alveolar complex formation / 대한해부학회지

Wnt/beta-catenin signaling plays a critical role in bone formation and regeneration. Dentin and cementum share many similarities with bone in their biochemical compositions and biomechanical properties. Whether Wnt/beta-catenin signaling is involved in the dento-alveolar complex formation is unknown. To understand the roles of Wnt/beta-catenin signaling in the dento-alveolar complex formation, we generated conditional beta-catenin activation mice through intercross of Catnb+/lox(ex3) mice with Col1a1-cre mice. In mutant mice, tooth formation and eruption was disturbed. Lower incisors and molars did not erupt. Bone formation was increased in the mandible but tooth formation was severely disturbed. Hypomineralized dentin was deposited in the crown but roots of molars were extremely short and distorted. In the odontoblasts of mutant molars, expression of dentin matrix proteins was obviously downregulated following the activation of beta-catenin whereas that of mineralization inhibitor was increased. Cementum and periodontal ligament were hypoplastic but periodontal space was narrow due to increased alveolar bone formation. While cementum matrix proteins were decreased, bone matrix proteins were increased in the cementum and alveolar bone of mutant mice. These results indicate that local activation of beta-catenin in the osteoblasts and odontoblasts leads to aberrant dento-alveolar complex formation. Therefore, appropriate inhibition of Wnt/beta-catenin signaling is important for the dento-alveolar complex formation.

Expression of Uchl1 in the Dental Epithelium during Mouse Tooth Development / 체질인류학회지

Tooth is formed by the reciprocal interactions between the ectoderm and ectomesenchyme derived from neural crest. It has not been clear that neuronal factors involved in the morphogenesis and differentiation of tooth. To identify the roles of neuronal factors during the tooth development, the expression patterns and localization of Uchl1 were investigated in the developing mouse tooth germ by in situ hybridization and immunohistochemistry. Uchl1 transcripts were weakly expressed in the oral epithelium and dental lamina at bud stage. However, expression of Uchl1 was not found in the oral epithelium from cap stage and observed in the inner enamel epithelium, stellate reticulum and dental papilla. From the bell stage, Uchl1 was expressed in the inner enamel epithelium and ameloblasts. Uchl1, was appeared to be localized in the inner enamel epithelium and differentiating ameloblasts of molar and incisors at neonates. Uchl1 was localized strongly in the fully differentiated ameloblasts and adjacent papillary layer whereas localized weakly in the odontoblasts of the molar at postnatal day 5. From these results, Uchl1 was expressed and localized in the differentiating dental epithelium and ameloblasts during tooth development. The results suggest that neuronal protein, Uchl1 may play roles in the histo- and cyto-differentiation of non-neuronal dental epithelium.

The Clinical Usefulness of Transbronchial Lung Biopsy in Critically Ill Patients with Pulmonary Infiltrates of Uncertain Etiology / 결핵

BACKGROUND: Transbronchial lung biopsy (TBLB) has known to yield useful information for pulmonary infiltrates of uncertain etiology. However, the its safety and usefulness of TBLB has have not been conclusive in the critically ill patients with respiratory failure. Moreover, TBLB has not been recommended for patients with mechanical ventilation. This study was done conducted to investigate the diagnostic values and risks of TBLB performed on critically ill patients at bedside to obtain information on the pulmonary infiltrate of unknown etiology. METHODS: Twenty patients (21 admissions with 23 cases) with diffuse pulmonary infiltrates who were treated in a medical intensive care unit of a tertiary referral hospital from January 1994 to May 1998, were enrolled for this study. Their medical records were retrospectively reviewed. TBLB was opted when a noninvasive diagnostic work-up failed to reveal the cause for the pulmonary infiltrate. The procedure was performed at patients' bedside without assistance of fluoroscopy. Bronchial washing or bronchoalveolar lavage was performed on the same pulmonary segment before performing TBLB. RESULTS: Adequate specimens were obtained in 18 cases (78%). TBLB provided specific diagnosis in two cases. The results of TBLB suggested the underlying etiology in 9 cases; bacterial pneumonitis (4), hypersensitivity pneumonitis (1), polymyositis (1), radiation fibrosis (1), idiopathic pulmonary fibrosis (1), and BOOP (1). Therapeutic decisions were altered in 11 cases (47.8 %) based on the TBLB results. Pneumocystis carinii was found in the BAL fluid of another case. Ten patients with a therapeutic change and ten patients without a management change had mortality rates of 40% and 80%, respectively. The APACHE III scores were significantly higher in patients with complications (72.8+/-21.8) compared with those without complications (48.3+/-18.9) (p< 0.05). The complication rates were higher in those with mechanical ventilation (50 %) than in those without mechanical ventilation (33 %)(,) but the difference was not statistically significant (p= 0.3). Conclusions: TBLB may be a useful diagnostic option for critically ill patients with unknown cause of pulmonary infiltrates. However, it should be be used with care for patients with mechanical ventilation or for severely ill patients.