Effects of tooth germ microenvironment in vitro on the differentiation of dental pulp stem cell and ectoblast mesenchyme stem cell / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the differential ability of dental pulp stem cell (DPSC) and ectoblast mesenchyme stem cell (EMSC) that were cultured with tooth germ cell (TGC) as the tooth germ microenvironment.</p><p><b>METHODS</b>The TGC of 4-day old rat was used as the tooth germ microenvironment. The BrdU marked and determined DPSC and EMSC were cultured with the TGC respectively. The expression of cell surface antigen dentin sialoprotein (DSP) and alkaline phosphatase (ALP) activity were determined with double marker immunofluorescence. The differential ability of DPSC and EMSC were determined by the immunohistochemistry and image analysis in the tooth germ microenvironment.</p><p><b>RESULTS</b>The transformation efficiency of DSP positive cell in the EMSC co-culture group was higher than that in the DPSC co-culture group (P < 0.05). The transformation efficiency in the co-culture groups was higher than that in the non co-culture group after 7 days by the image analysis of immunohistochemistry (P < 0.05). The ALP activity in the co-culture groups increased after 3 and 7 days. The ALP activity in the EMSC co-culture group was higher than that in the DPSC co-culture group.</p><p><b>CONCLUSION</b>DPSC and EMSC cultured with TGC as the tooth germ microenvironment can be induced to differentiate into odontoblast. The ability of EMSC is higher than that of DPSC.</p>

Progenitor cells in mammalian maxillofacial and mandibular processes Source and differentiation phenotype / 中国组织工程研究

BACKGROUND: It remains unclear whether ectomesenchymal cells also derived from neural crest stem cell in mammals.OBJECTIVE: To understand the specific markers and differentiation directions of maxillofacial and mandibular processes progenitor cells,and to explore the source and differentiation phenotype of ectomesenchymal stem cells.METHODS: The expression and changes of expression profiles of rat ectomesenchymal cells at E9.5,E10.5,E11.5,and E12.5days were observed by immunohistochemistry and flow cytometry.RESULTS AND CONCLUSION: The progenitors expressed multi-lineage markers,including neural system and several rnesenchymal tissue types,importantly the facts that molecule profiles were changed with time prolonged,suggesting these progenitors were in active differentiating stage,so they were stem like cells or contain stem like cells.Moreover,small populations(2%-3%)of CD57 and P75 phenotypes were detected by flow cytornetry,suggesting that ectomesenchymal stem cells were derived from neural crest,which maintained a quantitative stabilization though it is gradually differentiate after localization.

The expression and function of Smad7 during human tooth germ development / 华西口腔医学杂志

<p><b>OBJECTIVE</b>To observe the temporal and spatial expression of Smad7 during human tooth germ development and evaluate the effect of Smad7 on tooth germ development.</p><p><b>METHODS</b>The expression of Smad7 and its changes at different stages of human tooth germ were detected by using immunohistochemical staining.</p><p><b>RESULTS</b>Smad7 was expressed at all stages of tooth germ, but the distribution patterns at various stages were different. It indicated that temporal and spatial expressing mode of Smad7 during human tooth germ development was specific, which was similar to that of TGF-beta its signal transducer Smad2/3.</p><p><b>CONCLUSION</b>Smad7 might play an important role in TGF-beta intracellular signaling for modulating the differentiation of ameloblasts and odontoblasts.</p>

Randomized controlled trial study for preventing dental fear during caries treatments / 中华口腔医学杂志

<p><b>OBJECTIVE</b>To determine the clinical effects of preventing dental fear (DF) by pre-operation-education or local anesthesia method during the process of tooth filling.</p><p><b>METHODS</b>150 school children, aged 7 to 12, participated present study. All of them suffered from occlusal caries on their mandibular first permanent molars. They were divided into 3 equal groups, and each had 50, 25 boys and 25 girls. Group1 (pre-operation-education): taking about 1 hour to show them science and educational video tape on caries, then, clinic environment, including machine and instruments, and answering their questions; Group2 (local anesthesia): about 15 minutes before treatment, injecting 1.8 ml of 2% lidocaine for local anesthesia; Group3 (blank): without any measurements for DF. After that, all subjects accepted same filling treatment as usual. DF of each case was evaluated by 3 evaluators blindly based on venham's clinical ratings of anxiety and cooperative.</p><p><b>RESULTS</b>Significant difference was found between groups (0.57 +/- 0.59, 0.83 +/- 0.66, 1.05 +/- 0.68, H = 18.646, P = 0.0001), also in DF rate (10%, 18% and 42%, chi(2) = 15.5031, P = 0.0004). But not between groups 1 and 2.</p><p><b>CONCLUSION</b>During decayed tooth filling treatment, pre-operation-education is better than that of local anesthesia method, in DF prevention.</p>

Cloning of full length cDNA sequence of the mouse ameloblastin / 中华口腔医学杂志

<p><b>OBJECTIVE</b>Screening for special genes of matrix proteins of dentin and enamel of mouse dental germ.</p><p><b>METHODS</b>A cDNA library of dental germ of mouse was screened by differential display. The interesting clones were sequenced.</p><p><b>RESULTS</b>Six positive clones were isolated from the cDNA library. The sequence of one of the six positive clones was homologous with the ameloblastin sequence of rat. There are 497 homologous base pairs between the 526 base pairs sequenced by pTriplEX 3' primer of this clone and the 32-580 sequence of the rat ameloblastin gene; and there are 533 homologous base pairs between the 567 base pairs sequenced by pTriplEX 5' primer of this clone and the 1285-1854 sequence of the rat ameloblastin gene.</p><p><b>CONCLUSIONS</b>The full length cDNA sequence of the mouse ameloblastin was cloned.</p>

Induced differentiation of rat ectomesenchymal cells to odontoblast-like cells——Setup of three-dimension culture model / 实用口腔医学杂志

Objective: To study the mechanism of differentiation of rat ectomesenchymal cells to odontoblasts. Methods: Ectomesenchymal cells were cultured in three-dimension culture model using collagen gel as frame, and the change of phenotype of ectomesenchymal cells were observed and detected by phase-contrast microscopy and immunohistochemistry after the cells had been treated by 10 ng/ml of bFGF or/and 100 ng/ml IGF-1. Results: 4 days after treatment by bFGF and IGF-1, the cells appeared to be odontoblast-like cells aligned parallelly and polarized with long cytoplasmic processes attached to one end of the cell body.The cells were positive for DSP expression. However, the cells were DSP negative and aligned disorderly in other groups. Conclusion: Ectomesenchymal cells can be induced to differentiate to odontoblast-like cells in three-dimension culture model with the treatment by bFGF and IGF-1.

Bioinformatical analysis of avirulent strain-specific DNA fragments from Streptococcus mutans of serotype c / 实用口腔医学杂志

Objective:To explore avirulent strain-specific new genes or new functions of already known genes from Streptococcus mutans of serotype c.Methods:Twenty-six DNA fragments unique to avirulent strain of Streptococcus mutans were sequenced.The sequences of these presumptive avirulence DNA fragments were subjected to homology search through BLASTn and BLASTx in public database,and their putative biological functions were analyzed.Results:The size of the DNA fragments ranged from 113 bp to 776 bp.The average G+C content was 38.27%,similar to that of the gene-codingsequences in Streptococcus mutans strain UA159 whose genome sequences were just completed.Seven clones were picked repeatedly.Of the nineteen DNA fragments,eight potentially represented new DNA fragments were registered in GenBank.The remaining DNA fragments showed high homology to known genes of Streptococcus mutans strain UA159.Conclusions: The gene analysis and identification supply the groundwork for further study of gene functions of the avirulent strain of Streptococcus mutans serotype c.

Construction of a suppressive gene library of serotype c Streptococcus mutans / 实用口腔医学杂志

Objective:To construct a suppression subtractive library of suppression-related genes from c serotype Streptococcus mutans (S.mutans). Methods:After being isolated from virulent and avirulent strain of S. mutans respectively, the intact and high-pure genomic DNAs were digested with restriction enzyme AluⅠ. The digested DNA of the avirulent strain ligated with an adaptor was used as tester DNA, and that of the virulent strain as driver DNA. Then the suppression subtractive hybridization(SSH) was carried out, the efficiency of ligation and subtraction were detected respectively. The subtracted fragments were inserted into vector pCR2.1 using T/A cloning kit and transformed into E. coli TOP10F' competent cells. The white colonies were selected to construct the suppression subtractive library. Results: Through electrophoresis of AluⅠ-digested DNAs, a smear ranged from 0.1 to 2.0 kb was observed. The ligation efficiency of tester DNA with adaptor was at least higher than 25 percent. The subtraction efficiency confirmed the success in enrichment of differential genes between virulent and avirulent strain of S. mutans. In the subtracted group, the appearance time of the 23S rRNA gene in both tester and driver DNA was later than that in the unsubtracted group by twelve cycles. It suggested that suppression subtractive hybridization happened indeed. Then the subtracted fragments were cloned and the suppression-related gene library between virulent and avirulent strain of S. mutans was constructed. Conclusions:The suppression subtracted library of suppression-related genes has been constructed.

Differentiation induction of dental mesenchymal cells into odontoblasts / 实用口腔医学杂志

Objective: To induce human dental mesenchymal cells to differentiate into odontoblasts in vitro.Methods:The cultured human dental mesenchymal cells were induced in two-dimensional culture model by bFGF(10 ng/ml)+IGF-1(100 ng/ml) or TGF-?1(5 ng/ml) for 4-7 d. Cell growth and morphology after induction were observed. The expression of human DSP protein and DSPP mRNA were detected by immunofluorescent staining and RT-PCR. Mineralization capability of the induced cells was evaluated using Von Kossa staining. Results:In both bFGF+IGF and TGF-?1 groups 20%-30% of the induced cells showed long single process.DSP protein and DSPP mRNA were observed in the induced cells.Mineralized nodules were found in the induction cultures.Conclusion: bFGF+IGF-1 or TGF-?1 can induce dental mesenchymal cells to differentiate into odontoblasts.

Nucleotide polymorphisms analysis of dentin sialoprotein / 实用口腔医学杂志

Objective:To analyse the nucleotide polymorphism of dentin sialoprotein(DSP) coden region in Chinese people. Methods:The DSP segments were amplified by PCR;single-stranded conformation polymorphism(SSCP) and DNA sequencing were employed to detect the nucleotide polymorphisms in DSP coden region. Results:Three single nucleotide polymorphisms(SNP) were found in DSP coden region,two were same sense SNPs resulting in no change of amino acid product,and one was missense SNP resulting in change of asparagine and aspartic acid. Conclusion:There are some SNPs existing in DSP coden region in Chinese people.

Transient expression of human dentin sialoprotein gene in COS-7 cells / 实用口腔医学杂志

Objective:To express human dentin sialoprotein (hDSP) gene in COS-7 cells. Methods:hDSP gene was subcloned into mammalian expression vector pcDNA3. The recombined plasmids were transfected into COS-7 cells using lipofectamune PLUS TM kit for transient expression. Western blot analysis and immunohistochemical staining were used to examine the gene products. Results:The constructed vectors were confirmed by digestion with restriction enzyme. An immuno-reaction positive band with relative molecular mass of 60 000 was found by Western blot analysis in culture supernatant and cytoplasms of COS-7 cells. Immunohistochemical staining showed strong positive particles in the cytoplasms. Conclution:hDSP gene can be expressed in COS-7 cells.

Expression of platelet-derived growth factor receptor in periapical granuloma / 实用口腔医学杂志

Objective: To investigate the expression of platelet-derived growth factor receptor (PDGF-R) in periapical granuloma.Methods:Immunohistochemical staining was conducted on prepared specimens of 15 cases of human periapical granuloma. Results:The expression of PDGF receptor ? was detected in fibroblasts,capillary endothelial cells,plasmacytes and macrophage cells in all the 15 cases of human periapical granuloma.Conclusion:These results suggested that these cells are the target cells of PDGF, and PDGF may play an important role in the lesion.

The effect of leukemia inhibitory factor on the proliferation and differentiation of ectomesenchymal cells of mandibular process in Balb/c fetal mice / 实用口腔医学杂志

Objective: To investigate the effect of leukemia inhibitory factor (LIF) on the of proliferation and differentiation of ectomesenchymal cells of mandibular process in Balb/c fetal mice . Methods: Ectomesenchymal cells from the E12.5 mice mandibular process were cultured in DMEM/F12 with 10 6u/L LIF (experimental group) or without LIF (control). The proliferation effect was detected by MTT assay, Brdu test and flow cytometry. Immunohistochemistry were used to identify the differentiation state. Results: By day 7 the A value of the experimental group was 0.38?0.03,that of the control 0.30?0.02 (P

RELEASE OF COLONY-STIMULATING FACTOR INDUCED BY ENDOTOXIN FROM BACTEROIDES MELANINOGENICUS ATCC 25845 / 微生物学通报

Present study investigated the effect of endotoxin from Bacteroides melaninogenicus ATCC 25845 on release of colony-stimulating factor (CSF)in mice. The bone marrow cells were cultured in semisolid agar medium,the number of colonies was as a level index of CSF. The results showed that as much as 0.1?g endotoxin could induce the release of CSF,moreover, The level of CSF increased with dose of endotoxin untill 50 ?g. The colony-stimulatin factor level of B. melaninogenicus endotoxin was 66.6?8.5(CFU-C). This endotoxin showed significant effect on bone marrow cells of mice.