Caregiver-reported dementia as a predictor of oral health among patients receiving home-visit dental treatment: A retrospective cohort study.

OBJECTIVE: To assess caregiver-reported dementia as a risk factor for retained roots, an indicator of poor oral hygiene, among patients receiving home-visit dental treatment in Japan. METHODS: The medical records of 231 dentate patients who received home-visit dental treatment (covered by public medical insurance) for more than 2 years were retrospectively analyzed. The number of teeth and retained roots at the initial and final examinations were obtained from the dental charts, and the "change in the number of retained roots from initial to final examination" was determined. The presence or absence of caregiver-reported dementia, diabetes, and osteoporosis, as well as the level of long-term care needed, were used as indicators of general health condition at the initial interview. Multiple regression analyses were conducted in five models that tested the association of independent variables (age, gender, observation period, general health, presence or absence of caregiver-reported dementia at the initial interview) with changes in the number of retained roots. RESULTS: In all models, the presence of caregiver-reported dementia at the initial interview was significantly associated with the change in the number of retained roots (p < .05). The adjusted coefficient of determination (R2 ) of model 5, which included all the predetermined independent factors, was .168. CONCLUSIONS: Caregiver-reported dementia may be a risk factor for an increase in the number of retained roots among patients who receive home-visit dental treatment and may serve as an indicator of the need for regular and proactive oral hygiene management.

Synthesis and intracellular transportation of type I procollagen during functional differentiation of odontoblasts.

The expression of type I collagen, the most component of dentin extracellular matrix proteins (ECMs) in odontoblast is correlated with the activity of dentin formation. Since odontoblast possesses a distinct cellular process for protein transport into the dentinal tubule, it is important to examine the intracellular protein localization. However, a study focusing on odontoblast processes has not been performed. Type I collagen is synthesized as procollagen, which is immediately converted to collagen upon secretion. After characterization of antiserum to rat type I procollagen, we investigated the intracellular localization of type I procollagen in odontoblasts during and after dentinogenesis, using immunohistochemistry and in situ hybridization. The level of mRNA expression decreased during dentinogenesis, whereas the intracellular localization of type I procollagen in odontoblast processes become more distinct. The percentage of dentinal tubules with type I procollagen increased significantly with aging. Odontoblasts in pulp horn, in particular, showed moderate expression of type I procollagen after dentinogenesis. Since loss of occlusion also caused a significant decrease in type I procollagen, we concluded that occlusal stimulation activated type I procollagen synthesis in odontoblasts. We also suggest that analysis of intracellular transport of type I procollagen via odontoblast processes may be a new approach to evaluation of odontoblast function.

Molecular cloning of PP2Ceta, a novel member of the protein phosphatase 2C family.

We have cloned a novel member of the mouse protein phosphatase 2C family, PP2Ceta. Sequence analysis suggests that PP2Ceta, PP2Czeta and NERPP-2C constitute a unique subgroup of the PP2C family. PP2Ceta had extremely low activity against alpha-casein compared with PP2Calpha and was localized mainly in cell nuclei, suggesting that PP2Ceta dephosphorylates a unique nuclear protein(s) in the cells.

Regulation of the interleukin-1-induced signaling pathways by a novel member of the protein phosphatase 2C family (PP2Cepsilon).

Although TAK1 signaling plays essential roles in eliciting cellular responses to interleukin-1 (IL-1), a proinflammatory cytokine, how the IL-1-TAK1 signaling pathway is positively and negatively regulated remains poorly understood. In this study, we investigated the possible role of a novel protein phosphatase 2C (PP2C) family member, PP2Cepsilon, in the regulation of the IL-1-TAK1 signaling pathway. PP2Cepsilon was composed of 303 amino acids, and the overall similarity of amino acid sequence between PP2Cepsilon and PP2Calpha was found to be 26%. Ectopic expression of PP2Cepsilon inhibited the IL-1- and TAK1-induced activation of mitogen-activated protein kinase kinase 4 (MKK4)-c-Jun N-terminal kinase or MKK3-p38 signaling pathway. PP2Cepsilon dephosphorylated TAK1 in vitro. Co-immunoprecipitation experiments indicated that PP2Cepsilon associates stably with TAK1 and attenuates the binding of TAK1 to MKK4 or MKK6. Ectopic expression of a phosphatase-negative mutant of PP2Cepsilon, PP2Cepsilon(D/A), which acted as a dominant negative form, enhanced both the association between TAK1 and MKK4 or MKK6 and the TAK1-induced activation of an AP-1 reporter gene. The association between PP2Cepsilon and TAK1 was transiently suppressed by IL-1 treatment of the cells. Taken together, these results suggest that, in the absence of IL-1-induced signal, PP2Cepsilon contributes to keeping the TAK1 signaling pathway in an inactive state by associating with and dephosphorylating TAK1.