The effects of cariogenic diets on salivary polypeptides secretion by the submandibular glands of SD rats were investigated. Cariogenic diets (Diet 2000 adjusted sucrose concentration to 56%) were administered to experimental rats at 3 weeks of age for 7 weeks and MF powder chow administered to controls. Submandibular saliva was intra-orally collected by the cannulation method for 1h. Octopamine (OCT) and isoproterenol (IPR) were used as sialogogues.
Dental caries incidence in molars of rats fed for 3 weeks on Diet 2000 was low, but caries lesions had spread into the dentin in rats fed on Diet 2000 for 7 weeks.
Saliva was subjected to HPLC carried out with a reverse phase column and eleven peaks were eluted with a linear gradient concentration of acetonitrile. The peaks were compared between the Diet 2000 and MF groups. Five peaks (P21, P24, P26, P28, P34) in IPR-stimulated saliva of the Diet 2000 group significantly increased in comparison with the control group, in contrast, the peaks in OCT stimulated saliva of the Diet 2000 group were not significantly different from the control group. Amino acid sequences of P21 (pentapeptide), P24 (decapeptide) and P28 (eicosapeptide) were K-L-L-A-R, K-L-L-A-R-S-P-L-G-R and P-P-SA-D-A-D-A-E-N-V-Q-E-G-E-S-A-P-P-A, respectively. These three peptides were presumed to be driven from Glx-rich proteins, as seen in amino acid sequences.
It is concluded that cariogenic diets accelerated N-and C-terminal fragmentation of Glx-rich proteins by proteases located in the cells of granular tubules of submandibular glands as post-translational modification during saliva secretion.

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The adsorption of metal ions to 14 species of microorganisms including oral bacteria and samples of dental plaque was investigated.
At around neutral pH, which is similar condition as the oral environment, high levels of silver adsorption to cells were demonstrated with Propionibacterium acnes and Fusobacterium nucleatum, while Porphyromonas gingivalis and Actinomyces levoris showed lower levels of silver adsorption.
Adsorption of copper ions was observed at higher levels in both P. acnes and Corynebacterium matruchotii. P. gingivalis and A. levoris strains showed only low level adsorption.
Samples of dental plaque from 3 different origins were collected from 2 adults respectively or collected and mixed from 124 dental students. These samples showed lower levels of nickel and silver adsorption than P. acnes, and higher levels of metal adsorption than P. gingivalis.
The release of the nickel ions, which has been well known as a causative agent for mucous epithelium and skin allergies, from P. acnes cells bound the metal ions by washing was examined.
The metal ions were readily released from the bacterial cells by washing with EDTA but not almost by water. This finding indicates that metal ions adsorbed to bacterial cells are not easily released by washing with water.
These results suggests that several oral bacteria and dental plaque possess an increased capacity for adsorption of dental metal ions in oral environments.

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HSP90 is a major member of heat shock proteins. In eukaryotic cells, there are two HSP90 genes, and hence, two HSP90 isoforms, α and β, are expressed. The purpose of the present study was to develop monoclonal antibodies (mAbs) that distinguish between the two isoforms of human HSP90.
Bacterially-expressed human HSP90α and β were used as antigens of immunization, separately. Thirtythree independent mAbs against HSP90 were obtained, and classified into the following categories under the criteria of enzyme-linked immunosorbent assay and immunoblotting analysis. Nine mAbs recognized both isoforms equivalently, five preferentially interacted with HSP90α, five preferentially interacted with HSP90β, and ten and three specifically recognized HSP90α and β, respectively. Only one mAb revealed a discrepancy under the two assay conditions. By use of the isoform-specific mAbs, the expression of HSP90 isoforms in human salivary gland adenocarcinoma cells was examined. Immunoblotting analysis with isoform-specific mAbs revealed the expression of two HSP90 isoforms in these cells. Moreover, the expression of HSP90α increased under heat shock conditions, but that of HSP90β was less affected. Therefore, the mAbs developed in this study should be useful for elucidation of the function and regulation mechanism of HSP90 isoforms.

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The purpose of this study was to examine the ultrastructure of the hard tissue formed after resorption at the root apex. On backscattered electron imaging, the backscattered electron (BE) dense layer was observed at the resorbed area. This layer mainly consisted of hydroxyapatite on the microarea X-ray diffraction, and corresponded to high Ca, P, and 0 intensities on the electron probe microanalysis. In the undemineralized section, the transmission electron microscope revealed the BE dense layer as a stratified structure made up of a bead-like arrangement of calcospherites, however, the course of the fibrils were unclear. In dissolved crystals of the demineralized section floating in distilled water in a knife boat, matrix fibrils of the residual tissue were observed lying across the layer, and occasionally, microfibrils were lying parallel to the layer without bundling. In addition, a lamellated layer-like pattern was observed in areas which contained few fibrils. This layer resembled acellular afibrillar cementum. These findings suggest that repair is slow following arrested resorption under a chronic inflammatory environment.

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It has been reported that low-power laser irradiation increases cell proliferation, ALP activity, collagen secretion, and bone formation. The author examined the histological and cytological features of cultured osteoblast-like cells after low-power laser irradiation. Nodule formation started earlier in the laser irradiated group than in the control group. Many mitotic cells were observed around these nodules in the laser irradiated group compared with the control group. Calcification appeared earlier in the irradiated group than in the control group. These nodules contained many large secondary lysosomes and autophagocytotic cells in the laser irradiated group compared with the control group.
In conclusion, the effect of low-power laser irradiation may differ according to the developmental stage of osteoblast-like cells. At the early cell differentiation stage, low-power laser irradiation may increase the turnover rate of osteoblast-like cells, which may show high metabolic activity with increased ALP activity, as well as collagen and bone matrix secretion. At the late cell differentiation stage, both turnover rate and apoptosis-like autophagocytosis maybe increased. The membranes of apoptosis-like autophagocytotsis may supply calcium deposite site showing calcified nucleation. Apoptosis-like autophagocytosis may supply Ca and P to the nodules, and Ca and P concentrations may be increased, resulting in greater bone formation than in the control group. Low-power laser irradiation may increase the metabolic activity of bone calcification and promote bone formation.

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