Chronic kidney disease (CKD) is often associated with increased fracture risk; however, the CKD-effects on bone microstructure and intrinsic material properties have not been fully elucidated. This study was undertaken to evaluate the time course of trabecular architectural changes and material properties of cortical bone in the tibia of a mouse model of high-turnover CKD. Male mice subjected to 5/6 nephrectomy (Nx, n=8) and those sham-operated (Sham, n=8) were used. Starting at 8 weeks of age (2 weeks after surgery), Nx mice were fed with high phosphate diet. The tibial metaphysis was scanned by in vivo micro-computed tomography (μCT) for trabecular architecture analysis from 10 to 26 weeks of age with 4-week interval. Then, the animal was blood-sampled before sacrifice, and the scanned tibia was harvested. The midlayer of a cortical cross-section was evaluated for mineral-to-matrix ratio, mineral maturity, and collagen maturity by Fourier transform infrared microspectroscopy and for stiffness and hardness by the nanoindentation test. Serum chemicals showed the successful induction of high-turnover CKD in Nx. The age-related regression of trabecular network was observed in both groups but to the higher degree in Nx. In vivo μCT revealed significant interactions between age and CKD in trabecular number, thickness, and separation. On the other hand, the chemical and mechanical properties of cortical bone did not differ significantly between Nx and Sham. Thus, the compromised trabecular architecture will be contributory to bone fragility in high-turnover CKD.

View full abstract

The incidence of root caries and hyperesthesia in elderly people tend to increase with increasing age. This can be prevented by enhancing the root surfaces against aciduric bacteria. In order to prevent root caries, a chewing gum containing calcified seaweed rich in Ca, Mg, Na, F and P was created. A dentin block was made from the cervical part of the third molar after removing the cementum. The dentin blocks were immersed in remineralizing solution with extract of the gum with or without calcified seaweed for 2 weeks. The dentin blocks were immersed in demineralizing solution for 6 hours and acid resistance was evaluated after. Demineralization was evaluated by CMR image, demineralization depth (Ld) and mineral loss quantity (ΔZ) by image analysis, qualitative analysis by EPMA and the surface structure with the SEM. CMR image analysis revealed that the region immersed in aciduric solution had less quantity of demineralization than the region which was not immersed. A significant difference in Ld and Δ Z of the demineralization area after the aciduric treatment between the solution with calcified seaweed and the solution without aciduric treatment (p<0.05) was observed. Levels of Ca, P and Mg were detected in EPMA except for F. In SEM, the dentinal tubules of the demineralized region without aciduric treatment was enlarged which was not seen in demineralized region after aciduric treatment. The results indicate that the chewing gum with calcified seaweed is effective in increasing dentinal acid resistance.

View full abstract

Dysbacteriosis of intestinal flora is closely related to human health and disease development. In this study, the effects of ceftriaxone (INN) sodium on dominant bacteria in mouse with intestinal dysbacteriosis and on protein expressions in cecal contents were investigated. The dominant bacteria including Streptococcus, Veillonella, Bifidobacterium, Enterococcus, Staphylococcus, Bacteroides, Lactobacillus, Fusobacterium, Peptococcus and Enterobacteriaceae were either eliminated or inhibited by INN sodium administration. Protein (peptide) profile in cecum changed significantly as detected by matrix-assisted laser desorption ionization-time of flight-mass spectrometry (MALDI-TOF-MS) “fingerprinting” trapping assay. The average values and intensities of mass ion peaks of proteins in mice with intestinal dysbacteriosis were different from the normal mice. Principal component analysis (PCA) based hierarchical cluster analysis showed that the mass spectra of the cecal contents of both groups have phylogenetic-like relationships by matching their group classification. MALDI-TOF-MS analysis is feasible, rapid and powerful in capturing protein changes with high sensitivity in cecal contents of mice with intestinal dysbacteriosis induced by antibiotics. The approach used in current work potentially provides new input in the study of the role of intestinal flora in human diseases.

View full abstract

To examine the applicability of elastic recoil detection analysis (ERDA) in studying element constituents of dental hard tissues.
The concentration of all elements using high-energy heavy ions was detected in extracted teeth of both dentitions. The main elements present in enamel (calcium, phosphorus, oxygen, hydrogen), along with nitrogen, carbon, fluorine, sodium, magnesium and zinc, were measured. Concentrations and depth profiles were calculated and compared with simulation data generated using two programs, KONZERD and SIMNRA.
Enamel calcium, phosphorus, oxygen, hydrogen, nitrogen, carbon, fluorine, sodium, magnesium and, occasionally, zinc were detected. One-third of samples showed a constant concentration of the constituents over the analyzed depth, whereas the remaining samples had pronounced surface contaminations of carbon and nitrogen. Although calculation of concentrations with KONZERD gave expected values, simulation with SIMNRA was not possible since no agreement could be obtained between simulated and measured results for the elements.

View full abstract

The aim of this study was to monitor changes in bone density and bone quality (microarchitecture) in the femoral epiphyseal region in rats with bone loss induced by oestrogen deficiency and accelerated by mineral deficiency. Forty-eight Wistar rats were divided into 3 groups (n = 16 per group): Group 1, sham-operated rats on a normal diet; Group 2, ovariectomised rats on a normal diet; and Group 3, ovariectomised rats on a mineral-deficient diet. Observations were conducted 4, 8, 16, and 24 weeks after the operation (sham or ovariectomy), while the rats were on their respective diets. Microscopic computed tomography of the femoral epiphyseal region was used to generate 3-dimensional bone density distribution maps, and to compute bone density values. Densities of cortical and cancellous bone in Groups 2 and 3 were significantly less than densities in Group 1, and densities in Group 3 were significantly less than densities in Group 2 at nearly every post-operative time interval.
This study demonstrated that: a) ovariectomy in rats induces bone loss; b) a mineral-deficient diet accelerates bone loss that has been induced by oestrogen deficiency; and c) 3-dimensional bone density distribution maps may be useful in diagnosing osteoporosis and other diseases causing bone loss. Microscopic computed tomography is a powerful analytical tool for measuring spatial variations in bone density, and temporal changes in the patterns of 3-dimensional bone density distribution maps.

View full abstract

Quorum sensing (QS) refers to the phenomenon characterized by the accumulation of signaling molecules enabling a cell to sense a bacterial population triggering a coordinated response. Enterococcus faecalis is a resistant microorganism commonly found in oral infections. Salvadora persica has been traditionally used in Middle East countries to clean the teeth due to its antimicrobial activity. The study investigated the anti-quorum sensing (AQS) ability of S. persica extracts on E. faecalis. Extracts from the bark, leaves, root and shoots were tested against Chromobacterium violaceum. AQS ability was determined using differential scanning fluorimetry (DSF) and elastolytic assay to detect the level of protease and quantitative polymerase chain reaction (QPCR) to detect cytolysin (cylR1) and gelatinase (gelE) virulence factors. Preliminary disk diffusion assays revealed AQS activity by inhibiting violacein pigment production in C. violaceum without affecting its growth. Furthermore, only negligible amount of proteases was detected in DSF and elastolytic assays. CylR1 and gelE gene expression revealed no detectable signals even from the lowest possible threshold. The results indicate that S. persica has AQS ability against E. faecalis. S. persica extract can be used as alternative or in combination with other anti-microbial agents against infections caused by E. faecalis.

View full abstract

The calcifying epithelial odontogenic tumor (CEOT) is a benign but locally-invasive odontogenic neoplasm believed to take origin from the stratum intermedium of the developing tooth germ. Bone morphogenetic proteins (BMPs) are multifunctional signaling molecules that regulate diverse cellular processes including epithelial-mesenchymal interactions during odontogenesis. Aberrant BMP activity has been enumerated in the ameloblastoma but information about its distribution in the CEOT remains limited. The aim here was to investigate BMP expression in CEOT and to speculate on its significance. Immunolabelling for BMP-2 and BMP-7 was performed on archival tissues of six CEOT cases and the level of expression was quantified as negative (0), mild (+), moderate (2+) and strong (3+). Results disclosed that CEOT epithelium demonstrated co-expression of BMP-2 and -7 suggesting upregulation of these proteins at sites of tumor differentiation. Distribution patterns were distinct with some overlap. Their localizations were largely membranous and/or cytoplasmic. Amyloid-like materials strongly expressed BMP-7 but were nonreactive for BMP-2, implicating that these signaling proteins play differential roles in the formation of these extracellular products. Mineralized substances including Liesegang rings were mostly negative for both BMPs suggesting that calcification process is associated with repression of these molecules. Stromal endothelium and fibroblasts were stained variably positive. BMP was heterogeneously detected in the CEOT epithelium at the tumor advancing front suggesting their upregulation at active sites and downregulation in quiescent areas. Present findings suggest that BMP-2 and BMP-7 most likely play differential roles in the cellular differentiation and progression of CEOT. BMP-7 accumulation within amyloid-like protein is a novel finding.

View full abstract

To gain insight into the regulation mechanism associated with retinoic acid (RA) induced cleft palate, gene expression profiles of secondary palate on embryonic day 14 was investigated by using Affymetrix Mouse Gene Chip. RA-induced cleft palate mouse model was made, 27 cleft palate embryos and 18 embryos in control group on embryonic day 14 were harvested. Related genes were examined in the palate of these mice by genechip. Using the twice significance of difference as the standard, totally there were 81 up-regulated transcripts and 1249 down-regulated ones in RA-treated group compared with control group, gene functional categories and pathways, particularly involved in transcription regulator activity, regulation of growth, direction of cell movement, cytoskeleton, Wnt and Hedgehog families as well as actin cytoskeleton pathway were identified. These data proved that growth inhibition is the main cause for cleft palate formation treated by RA in the stage, meanwhile, cell movement, intracellular transport and cell division are also involved through interaction of Wnt and Hedgehog pathway with RA singnaling. It has highlighted potential cascades and important candidates for further investigation on the genetic mechanism and clinical therapy of cleft palate.

View full abstract

The effect of low-intensity pulsed ultrasound stimulation (LIPUS) on bone formation around dental implants was studied histologically and mechanically after a dental implant was inserted into the femur of male Japanese white rabbits. LIPUS daily treatment started on the day after implant placement for 14 days. Histologically, new bone formation was observed around the implant. Implant removal torque values were significantly higher in LIPUS-treated group (44.0 - 58.8 N·cm) than the control group (32.0N·cm). Moreover, bone contact ratio was significantly higher in LIPUS-treated group than the control group. The results suggest that clinical application of LIPUS for dental implants may promote osseointegration.

View full abstract

Teeth are important structures for masticatory and phonetic purposes. Loss of teeth decreases these functions leading to impaired quality of life. Missing teeth replaced by tooth regeneration may be possible with emerging advances in stem cell biology and tissue engineering. Recent investigations have demonstrated that bone marrow derived cells (BMDC) can differentiate into cells other than blood cells. In the present study, the ability of BMDC to differentiate into tooth forming tissues was investigated using bone marrow transplantation model. BMDC from green fluorescent protein (GFP) transgenic mice were transplanted into 8-week old, C57BL/6 immunocompromised mice, which underwent 10-Gy whole body lethal irradiation. Immunohistochemical analysis revealed that bone marrow cells are positive to GFP, confirming successful bone marrow transplantation. Diffusedly GFP-positive cells were observed within the dental pulp of mouse incisor. GFP-positive cells in the dental pulp have arborescent processes resembling dendritic cell-like cells. Some odontoblast-like cells were also positive to GFP. Cells positive to GFP were observed in the cervical loop region and periodontal ligament. Langerhans cells in the oral epithelium, stromal fibroblasts, blood vessels and osteoclasts were also positive to GFP. These results indicate that BMDC have the ability to differentiate into tooth, bone and connective tissues.

View full abstract

Objective: The study was designed to determine the immune mechanism of nucleic acid sequences present in the medium filtrate of lactobacillus DM8909 at exponential growth phase. The effect of extracellular nucleic acids on TLR9 on the expression of IL-6 was also investigated.
Methods: Three groups were formed as nucleic acid group, CpG-ODN group and control group. Extracellular nucleic acids were examined by TA cloning and sequencing technology. RT-PCR and ELISA were used to detect the expressions of TLR9 and NF-κBp65 in HT-29 cells and the presence of IL-6 in the medium.
Results: The nucleic acids detected in the medium filtrate of lactobacillus DM8909 at exponential growth phase were found to be RNAs. A total of 39 RNA sequences were identified as lactobacillus delbrueckii subsp. Bulgaricus with a size of 49 bp, 23S ribosomal RNA and another RNA with a size of 52 bp identified as lactobacillus rhamnosus, ATCC 53103, tRNA-Leu sequence. TLR9 expressions in CpG-ODN and nuclei acid groups were higher compared to the control group (TLR-9 values were 3.2386, 0.4984 and 0.1780 respectively). The same results were obtained for NF-κBp65 where the expressions in CpG-ODN and nucleic acid groups were higher than the control group (relative values were 1.6671, 0.6501 and 0.3094 respectively). Furthermore, IL-6 expressions in CpG-ODN and nucleic acid groups were significantly higher than the control group (P <0.05, (relative values were 23.6735 ± 1.4515, 20.2041 ± 1.6820 and 15.7143 ± 0.7047 respectively).
Conclusion: The extracellular nucleic acids in the medium of lactobacillus DM8909 are RNAs and they could elevate the level of IL-6 through the activation of NF-κB and TLR9 in vitro. These molecules have similar immune activity with CpG-ODN.

View full abstract

Aneurysmal bone cysts account for less than 1% of primary bone tumors and have a predilection for the metaphyses of the long bones of the leg. Only 1% of all aneurysmal bone cysts occur in the patella. We report on a 24-year-old man with a primary aneurysmal bone cyst in the left patella treated with curettage. The defect was filled with autogenic and allogeneic cancellous bone graft. The patient experienced no pain or tenderness and had a full range of knee movement.

View full abstract