Takaaki Aoba

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Mature enamel consists of densely packed and highly organized large hydroxyapatite crystals. The molecular machinery responsible for the formation of fully matured enamel is poorly described but appears to involve oscillative pH changes at the enamel surface. We conducted an immunohistochemical investigation of selected transporters and related proteins in(More)
The present study reports on the separation of fluid from soft, “cheeselike” enamel of porcine permanent teeth in the secretory stage, and the determination of its chemical composition. The enamel tissues were dissected from mandibles of 5 to 6-month-old piglets and pooled under mineral oil in centrifuge tubes, and then centrifuged at 1.9–2.4×105 g for(More)
A mouse cDNA encoding a 180 amino acid amelogenin was subcloned into the pET expression plasmid (Novagen, Madison, WI) for production in Escherichia coli. A simple growth and purification protocol yields 20–50 mg of 95–99% pure recombinant amelogenin from a 4.5-liter culture. This is the first heterologous expression of an enamel protein. The expressed(More)
This review aims at discussing the pathogenesis of enamel fluorosis in relation to a putative linkage among ameloblastic activities, secreted enamel matrix proteins and multiple proteases, growing enamel crystals, and fluid composition, including calcium and fluoride ions. Fluoride is the most important caries-preventive agent in dentistry. In the last two(More)
  • Takaaki Aoba
  • Critical reviews in oral biology and medicine…
  • 1997
Fluoride participates in many aspects of calcium phosphate formation in vivo and has enormous effects on the process and on the nature and properties of formed mineral. The most well-documented effect of fluoride is that this ion substitutes for a column hydroxyl in the apatite structure, giving rise to a reduction of crystal volume and a concomitant(More)
The selective adsorption of amelogenins onto synthetic hydroxyapatite (HA) and their inhibitory activity on the seeded HA crystal growth were investigated using enamel proteins obtained from the outer layer of immature porcine-enamel (soft, cheeselike in consistency) of developing permanent incisors. Special interests were paid to the effect of a(More)
BACKGROUND Enamel mineralization taking place during amelogenesis is a unique model to investigate carbonatoapatite formation in vivo. The abundance of proteinaceous crystal growth inhibitors, in particular amelogenins, contributes significantly to the mineralization process. Their putative roles are to prevent random proliferation of crystal nuclei and to(More)
Acid phosphate is one of the major impurities incorporated into bioapatites, and its quantity and environment in forming mineral have been used as diagnostic probes to pursue acidic precursor(s). Currently, little is known about the structural feature of nonstoichiometric octacalcium phosphate (OCP), which has been advocated to be, most plausibly, mineral(More)
Although ex vivo expanded mesenchymal stem cells (MSC) have been used in numerous studies, the molecular signature and in vivo distribution status of MSC remain unknown. To address this matter, we identified numerous human MSC-characteristic genes--including nine transcription factor genes--using DNA microarray and real-time RT-PCR analyses: Most of the(More)
NOD/LtSz-prkdc(scid)/prkdc(scid) (non-obese diabetic-severe combine immunodeficiency; NOD-scid) mice grafted with human peripheral blood lymphoid cells have been used as an in vivo humanized mouse model in various studies. However, cytotoxic human T cells are induced in this model during immune responses, which gives misleading results. To assist in(More)