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Here, we report on the first attempt to bioengineer tooth using a spontaneously immortalized mesenchymal cell line. To assess the odontogenic potential of this cell line, odontoblast-lineage cells (OLC) were re-associated with competent dental epithelium isolated from E14.5 mice. A novel three-dimensional organ germ culture method was applied to nurture the constructs in vitro. Additionally, recombinants were transplanted under the kidney capsule in host animals for 2 weeks. Transplants developed into tooth tissues in one-third of the cases. OLC-derived GFP-positive cells could be identified in mineralizing tooth germs by immunohistochemistry. OLCs were capable of intercellular and cell-matrix communication, thus they eventually differentiated into functional odontoblasts. In summary, we managed to utilize OLCs for dental mesenchyme substitution in tooth regeneration experiments. Therefore, our spontaneously transformed cell line proved its potential for future complex, tooth developmental and bioengineering studies.

We evaluated tissue changes associated with cerium chloride administration via gavage to adult mice, via milk to neonatal mice and transplacentally to fetal mice. Change in adults consisted of extensive pulmonary hemorrhage, pulmonary venous congestion, thickened alveolar septae, hepatic necrosis and neutrophil infiltrations. Those in fetal mice consisted of pulmonary and hepatic congestion. These results indicate that gavage cerium administration elicited subtle tissue changes, though oral toxicity is rather low. These changes were less severe in neonatal and fetal mice. When cerium was injected into adult mice through the tail vein, cerium was distributed mainly to the liver, spleen and lung dose-dependently with the cerium concentration gradually decreasing after 3 days. A study of cerium anticoagulation in mouse plasma showed that clotting time was significantly prolonged when cerium was added to plasma. These results suggest that cerium may disturb blood coagulation and cause pulmonary and hepatic vascular congestion.

Objective: In order to investigate whether repeated immunization induces changes in IgG glycosylation, we analyzed the composition of oligosaccharides on antigen-specific IgGs obtained from mice that received different amounts of immunization boosts. Methods: Three groups of mice were immunized with ovalbumin (OVA) and boosted once, twice, or three times, respectively, with an interval of 1 week. The patterns of oligosaccharides present in anti-OVA specific IgGs were analyzed using lectin-enzyme-linked immunosorbent assay (ELISA) and lectin-blot. Results: The repeated injection of OVA induced both the production of specific IgGs and an increase of fucose content in N -linked oligosaccharides of the IgGs. The lowest IgG fucosylation was observed in mice boosted once, whereas the highest fucosylation rate was observed in mice boosted three times. ELISA assay demonstrated that there was a positive relationship between the fucose content and amount of immunization boosts. Conclusions: IgG fucosylation increases during repeated immunization with ovalbumin. The alteration of IgG fucosylation may have important biological significance.