The relationship between vitamin D receptor gene polymorphism and deciduous tooth decay in Chinese children.

BACKGROUND: In the present study, we explored the link between vitamin D receptor (VDR) BsmI, TaqI, ApaI and FokI gene polymorphisms with deciduous tooth decay in Chinese children. METHODS: Our study included 380 Chinese children aged 4-7 years, whose DNA sample was collected from the buccal mucosa. VDR gene polymorphisms was determined by PCR-RFLP. RESULTS: The adjusted logistic regression analysis demonstrated that BsmI containing the Bb genotype was linked with the increased risk of deciduous tooth decay (OR = 1.856, 95% CI = [1.184, 2.908], p = 0.007). However, VDR polymorphisms ApaI, TaqI and FokI were not associated with deciduous tooth decay (ApaI: OR = 0.839, 95% CI = [0.614, 1.145], p = 0.268; TaqI: OR = 1.150, 95% CI = [0.495, 2.672], p = 0.744; FokI: OR = 0.856, 95% CI = [0.616, 1.191], p = 0.356). CONCLUSIONS: Our results showed that VDR BsmI polymorphism was associated with the risk of deciduous tooth decay in Chinese children aged 4-7 years. However, the specific mechanism remains to further verify through experiment.

The complete mitochondrial genome of the black field cricket, Teleogryllus oceanicus.

In this study, the complete mitochondrial genome sequence of the black field cricket, Teleogryllus oceanicus, with the total length of 15 660 bp is determined for the first time. This mitochondrial genome harbors 13 protein-coding genes (PCGs), 22 transfer RNA genes (tRNA), two ribosomal RNA genes (rRNA), and one control region (D-loop). The overall base composition is A (40.44%), C (17.12%), G (9.84%), and T (32.60%), so the slight A-T bias (73.04%) was detected. Phylogenetic analysis showed that T. oceanicus is closely related to T. emma that is also a member of the genus Teleogryllus.

[Effects of interleukin-1ß on mineralization potential of dental pulp stem cells].

OBJECTIVE: To investigate the effects of pro-inflammatory cytokine interleukin-1ß (IL-1ß) on mineralization potential of dental pulp stem cells (DPSC). METHODS: Rat DPSC were cultured in vitro and randomly divided into three groups, IL-1ß (10 µg/L), osteogenic inductive medium and non-osteogenic inductive medium. After 3, 7, and 12 days of treatment, the cultures were evaluated for cell proliferation and calcium deposit. Real-time polymerase chain reaction was used to detect the gene expression levels of osteocalcin (OC), bone sialoprotein (BSP), dentin sialophosphoprotein (DSPP) and dentin matrix protein 1 (DMP-1). In vivo test, after 3 day's treatment with IL-1ß, the cell-scaffold complexes were implanted subcutaneously in mice for 8 weeks. Histological analysis was performed to evaluate hard tissue formation. RESULTS: In vitro test, after 3-day's treatment, IL-1ß improved cell proliferation to 137.22 DNA µg/L and cell viability becomes (97.12 ± 7.18)% of control. The gene expression levels of OC, BSP, DSPP and DMP-1 are (378.19 ± 16.22)%, (427.12 ± 18.22)%, (247.19 ± 10.11)% and (198.29 ± 10.23)% respectively. The results of IL-1ß's group was notable increased compared with non-osteogenic induction medium and the statistical differences are significant. IL-1ß induced the odontogenic differentiation of DPSC. However, these effects tended to continuously decrease with treatment time. Histological analysis demonstrated that in the group treated with IL-1ß hard tissue was markedly formed in vivo. CONCLUSIONS: IL-1ß may induce the mineralization of DPSC and play an important role in host defenses and tissue repair.

[Protective efficacy of a new fusion anti-caries DNA vaccine encoding antigens of both Streptococcus mutans and Streptococcus sobrinus].

OBJECTIVE: To construct a new fusion anti-caries DNA vaccine pGJGAC/VAX encoding antigens of both S. mutans and S. sobrinus so as to enhance the protective effect of DNA vaccine against S. sobrinus infection. METHODS: The CAT fragment of S. sobrinus OMZ176 gtf-I was amplified by semi-nest PCR and then inserted into the plasmid pGJA-P/VAX to construct the recombinant plasmid pGJGAC/VAX. The CHO cell was transfected and the expression of fusion protein detected using cellular immunohistochemistry and Western blot. Mice were immunized with pGJGAC/VAX and control plasmids via the intramuscular (i.m) or intranasal (i.n) routes. During the experiment, blood and saliva samples were collected at a 2-week interval for antibody assay by ELISA. Rats were orally challenged with S. mutans Ingbritt or S. sobrinus 6715 and then immunized i.n with pGJGAC/VAX, pGJA-P/VAX or pVAX1. The Keyes method was used to determine the caries activity. RESULTS: (1) CAT sequence was identical to the related sequence of gtf-I (OMZ176) in GenBank. The recombinant plasmid pGJGAC/VAX encoded the genes of antigens of both S. mutans and S. sobrinus. The expressed protein could respond to specific anti-PAc, anti-GLU and anti-CAT antibodies respectively. (2) As for antibody reactions, mice in the experiment group had significantly higher levels of anti-PAc, anti-GLU and anti-CAT IgG antibodies than those in the pVAX1 group (P < 0.01). The peak responses of specific anti-CAT antibodies were observed at 8 weeks (GAC/i.m) and 10 weeks (GAC/i.n) and were approximately 62.13 microg/ml and 11.43 microg/ml respectively. The peak responses of specific anti-CAT IgA antibodies were seen at 8 weeks (GAC/i.m) and 10 weeks (GAC/i.n) and were approximately 0.67% and 0.80% respectively. (3) In the group infected with S. mutans or S. sobrinus, the pGJGAC/VAX-immunized rats showed significantly fewer E, Ds and Dm lesions than pVAX1-immunized rats (P < 0.05) and decreased Ds and Dm levels than pGJA-P/VAX-immunized rats (P < 0.05) while there was no obvious difference in E lesions between the two groups (P > 0.05). CONCLUSION: A new fusion anti-caries DNA vaccine pGJGAC/VAX encoding antigens of both S. mutans and S. sobrinus is constructed successfully and expressed correctly in eukaryotic cells. It induces effective mucosal and systematic humoral responses so as to provide a better protection against S. sobrinus.

[Construction of human bone morphogenetic protein-7 gene fluorescent eukaryotic cell expression vector and test of bioactivity in vitro].

OBJECTIVE: To construct fluorescent eukaryotic cell expression vector with human bone morphogenetic protein-7 (hBMP-7) gene and to transfect mouse stromal cell line W-20-17 to detect the bioactivity of pEGFP-hBMP-7 in vitro. METHODS: pEGFP-hBMP-7 plasmid was constructed by subcloning technique and identified by enzyme cutting and electrophoresis. W-20-17 cells were transfected with pEGFP-hBMP-7 by means of lipofectamine-2000 media methods. Transfection efficiency and gene expression were evaluated by fluorescent microscopy. ALP, von Kossa and osteocalcin (OC) were tested to determined the phenotypes of osteoblast. RESULTS: After 48 hours, the gene transfection efficiency was 40%. Based on GFP and immunofluorescence of pEGFP-hBMP-7, there was the expression of aim gene. After gene transfection, there were not significant different of cell morphology feature and cell proliferation. ALP activity, the number of calcium nodules and the expression of OC increased. CONCLUSIONS: pEGFP-hBMP-7 with bioactivity was constructed, which could induce W-20-17 cells to differentiate to osteoblasts.

[Identification and isolation of human dental pulp stem cells].

OBJECTIVE: To isolate and cultivate human dental pulp stem cells (DPSCs). METHODS: Pulp tissue was removed from healthy young human teeth extracted for orthodontic purposes. The pulp was digested by Type I collagenase and dispase. Then single-cell suspensions were obtained by filter and cultivated. The clones were identified by expression of STRO-1. Under the conditions of inducement, clones were identified by activity of alkaline phosphatase (ALP), formation of mineralized nodule and expression of dentin sialoprotein (DSP), and by Oil Red-O dyeing and expressing of PPARr2. RESULTS: The clones had positive expression of STRO-1. When stimulated to differentiation, these cells took on dramatically high activity of ALP, had the ability of mineralization and expressed DSP. These cells also had ability to trans-differentiate into adipocytes. CONCLUSION: There are stem cells in human dental pulp tissues, which can be isolated and cultivated.

[Osteogenic differentiation of synovial mesenchymal stem cells in vitro].

OBJECTIVE: To investigate the potential of synovial mesenchymal stem cells (SMSC) in osteogenic differentiation. METHODS: SMSC were obtained by limited dilution method and expanded to culture in 25-milliliter flasks. The attached cells were treated with inductive medium containing dexamethasone, glycerophosphate and vitamin C at 3rd passage SMSC. The mineralized nodule was stained by Von Kossa method. The expression of ALP and osteopontin were detected by histochemical, immunohistological staining technique, respectively, while the expression of cbfa1 mRNA by RT-PCR. RESULTS: Pure SMSC which were of spindle shape and star shape, uniform in size, could be induced to pleomorphism osteoblast in vitro, which were intensive positive in ALP and osteopontin. The expression of cbfa1 mRNA were also verified by RT-PCR and the polygonal cells formed nodular structure at 4 weeks. All these were coincident with the characters of osteoblast. CONCLUSION: SMSC can be purified and induced into osteoblast in vitro.