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Biomedical subjects

Zhuan Bian

Publications and source records attributed to Zhuan Bian.

At least 19 recordsLinked to original sources
PubMed2006

Salivary mutans streptococci counts as indicators in caries risk assessment in 6-7-year-old Chinese children.

OBJECTIVES: This study aimed to determine whether salivary mutans streptococci (MS) counts in Chinese children had any value in the prediction of new caries in the permanent dentition in the age interval of 6.5-8.5 years. METHODS: Four hundred and thirty-three 6-7-year-old children participated in this 2-year longitudinal study. Salivary MS counts were obtained at baseline with the spatula method. Dentin and enamel caries was recorded at baseline and at the follow-up, 2 years later. Spearman's correlation coefficients were computed. Past caries experience variables at baseline were entered into a multiple regression model with caries increment of the permanent dentition as dependent variable. MS counts were subsequently entered into the model to assess the additional caries predictive value. RESULTS: Spearman's correlation coefficient for MS counts and caries experience of the primary dentition at baseline was 0.48 and for MS counts and caries increment in the permanent dentition 0.12. In the multiple regression model caries increment of the permanent dentition had an adjusted R2 of 0.17 when the past caries experience variables were entered. Adding MS counts in the regression model did not change the R2 value. CONCLUSIONS: Salivary MS counts did not add any caries predictive value when past caries experience variables were used as caries predictors in this Chinese child population.

Child↗
PubMed2006

The performance of human dental pulp stem cells on different three-dimensional scaffold materials.

The aim of this study was to investigate the in vitro and in vivo behavior of human dental pulp stem cells (DPSCs) isolated from impacted third molars, when seeded onto different 3-dimensional (3-D) scaffold materials: i.e. a spongeous collagen, a porous ceramic, and a fibrous titanium mesh. Scaffolds were loaded with DPSC, and subsequently divided into two groups. The first group was cultured in osteogenic differentiation medium in vitro for 4 weeks. The second group of samples was implanted subcutaneously in nude mice for 6 or 12 weeks. Samples cultured in vitro were analyzed by scanning electron microscopy and RT-PCR for dentin sialophosphoprotein (DSPP) expression. In vivo samples were evaluated by histology, RT-PCR and immunohistochemistry. The results indicated that in vitro, cells developed abundant deposition of mineralized extracellular matrix (ECM) with expression of DSPP in all 3-D materials. The simultaneous implantation experiment showed formation of tissue that was DSPP positive in all three scaffolds materials. However, the aspect of the formed tissues in all scaffolds resembled more connective tissue than a dentin-like tissue. Limited calcification of the ECM was only seen in the ceramic scaffold. In both experiments, no other differences could be attributed to the different materials used. In conclusion, the in vivo behavior of DPSC and their relations with 3-D scaffold materials should be further studied before clinical use can be considered.

Animals↗
PubMed2006

Inhibition of SHH signaling pathway: molecular treatment strategy of odontogenic keratocyst.

Odontogenic keratocyst (OKC) is a relatively common cystic lesion occurred in the tooth-bearing areas of the jaws. This entity is thought to arise from the dental lamina or its remnant with significant growth capacity and recurrence potential. The Sonic hedgehog (SHH) signaling pathway plays a critical role in tooth development. Patched (PTCH) combines with Smoothened (SMO) to form a receptor complex for SHH ligand. Mutations in the PTCH resulting in aberrant activation of SHH signaling pathway were identified as the underlying genetic event of both sporadic and syndrome-related OKCs. We postulate that any strategy to develop antagonists of active receptor, transcriptional factors of SHH signaling pathway will be an effective treatment for OKC. These strategies include reintroducing a wild-type form of PTCH, inhibition of the SMO molecule by synthetic small antagonists and suppression of the downstream transcription factors of the SHH signaling pathway. It seems that inhibition of SMO by intracystic injection of antagonist protein of SMO is the most potential treatment choice.

Basal Cell Carcinoma↗
PubMed2006

Phenotypes and genotypes in 2 DGI families with different DSPP mutations.

OBJECTIVE: The objective of this study was to characterize dentin ultrastructural features resulting from a nonsense mutation in DSPP gene and to define various phenotypes associated with specific DSPP mutations in families with Dentinogenesis Imperfecta type II (DGI-II). STUDY DESIGN: Two families with DGI-II were investigated for phenotypes and genotypes. Mutation analysis was performed by amplifying DSPP exons and sequencing the products. Dentin ultrastructure associated with the specific mutation was examined with scanning electronic microscopy and transmission electronic microscopy. RESULTS: Teeth discoloration, attrition, and obliterated pulp chambers showed in affected members of 2 families. "Shell" teeth phenotypes were also presented in deciduous teeth of family 1. A nonsense mutation (c.133CT) in family 1 and a missense mutation (c.52GT) in family 2 were identified in DSPP. Irregular dentin tubules, smooth dentinoenamel junction with an obvious gap, abnormal enamel structure, and amounts of fibril bundles around dentin tubules were manifested in the specimen from family 1 with the nonsense mutation in DSPP. CONCLUSIONS: We reported characteristic tooth ultrastructure resulting from a nonsense mutation in DSPP gene and supported that the c.133CT and c.52GT in DSPP could be the 2 mutation hotspots. The same DSPP mutations may be causative for multiple unrelated DGI families with different clinical phenotypes.

Adult↗
PubMed2006

Germline mutations of the PTCH gene in families with odontogenic keratocysts and nevoid basal cell carcinoma syndrome.

BACKGROUND/AIMS: Odontogenic keratocysts (OKC) are aggressive lesions in the jaws, which can occur as isolated cases or in association with nevoid basal cell carcinoma syndrome (NBCCS). Mutations on PTCH gene have been identified in patients with NBCCS. It was hypothesized that PTCH mutations may be causative in isolated OKC. This study aims to investigate germline mutations of PTCH in families with OKC and NBCCS. METHODS: Three Chinese families with OKC and NBCCS were enrolled in the study. The diagnosis was based on examination and medical history. Mutation analysis was performed by amplifying all exons of PTCH and sequencing the products. RESULTS: One family with isolated OKC (family 1) and the other two families with NBCCS were diagnosed. Three novel germline mutations in PTCH were identified, including a missense mutation (p.S1089 > P) in family 1, a nonsense mutation (p.Q160X) in family 2 and a de novo mutation (c.768_777delGACAAACTTC) in family 3. CONCLUSIONS: It is proposed that isolated OKC can be inherited in an autosomal dominant mode. The results suggest that germline mutations on PTCH can cause isolated OKC, and that the PTCH gene responsible for NBCCS plays an important role in the formation of OKCs even when they are not syndrome-related.

Adult↗
PubMed2006

Immunogenicity of CTLA4 fusion anti-caries DNA vaccine in rabbits and monkeys.

Enhancement of mucosal and systemic immune responses is still a challenge for the application of DNA vaccine. Here, we show anti-caries DNA vaccines, pGJA-P and pGJA-P/VAX, encoding Streptococcus mutans antigens fused to cytotoxic T lymphocyte antigen-4 (CTLA4), which binds to B7 molecule expressed on the surfaces of antigen-presenting cells. Rabbits and monkeys were immunized via intranasal or intramuscular routes. The fusion vaccine induced accelerated and increased specific antibody responses in serum and saliva compared with non-fusion DNA vaccine in rabbits. Significant specific serum IgG and salivary IgA levels could be detected in fusion vaccine-immunized monkeys. Therefore, this study demonstrates that fusing antigens to CTLA4 results in enhancing immune efficacy and strongly suggests that it may represent a promising approach to prevent dental caries or other mucosal infectious diseases. These findings also suggest that CTLA4 fusion anti-caries DNA vaccine may be effective immunogen in primates.

Animals↗
PubMed2006

Incidence and factors associated with endodontic inter-appointment emergency in a dental teaching hospital in China.

OBJECTIVE: To assess the incidence of endodontic inter-appointment emergency (EIE) in a dental teaching hospital in China, and to correlate its occurrence with preoperative and treatment parameters. METHODS: Three thousand six hundred and ninety six cases were collected at root canal treatment appointments on demographics, presenting symptoms, treatment procedures and periradicular status. The operators consisted of faculty, undergraduate students and advanced trainees. Root canals were conventionally instrumented and then medicated. No systemic medication was prescribed. In cases EIE developed between appointments, an emergency visit was arranged and active treatment was carried out. The data of EIE cases were statistically analyzed using the chi-square test and a multiple logistic regression model. RESULTS: The overall incidence of EIE was 5%, which rate was 5.5% in females and 4.3% in males. Analyses of the potential factors revealed that patient age, tooth location, preoperative percussion pain and pulp status were the most important independent variables. CONCLUSION: EIE was significantly associated with some host factors (patient age, tooth location) and presenting factors (preoperative percussion pain, pulp status).

Adult↗
PubMed2006

A novel heterozygous deletion in the EVC2 gene causes Weyers acrofacial dysostosis.

Weyers acrofacial dysostosis (MIM 193530) is an autosomal dominant disorder clinically characterized by mild short stature, postaxial polydactyly, nail dystrophy and dysplastic teeth. Ellis-van Creveld syndrome (EvC, MIM 225500) is an autosomal recessive disorder with a similar, but more severe phenotype. Mutations in the EVC have been identified in both syndromes. However, the EVC mutations only occur in a small proportion of EvC patients. Recently, mutations in a new gene, EVC2, were found to be associated with other EvC cases. The EVC and EVC2 are located close to each other in a head-to-head configuration and may be functionally related. In this study, we report identification of a novel heterozygous deletion in the EVC2 that is responsible for autosomal dominant Weyers acrofacial dysostosis in a large Chinese family. This constitutes the first report of Weyers acrofacial dysostosis caused by this gene. Hence, the spectrum of malformation syndromes due to EVC2 mutations is further extended. Our data provides conclusive evidence that Weyers acrofacial dysostosis and EvC syndrome are allelic and genetically heterogeneous conditions.

Abnormalities, Multiple↗
PubMed2006

The effects of sodium hypochlorite (5.25%), Chlorhexidine (2%), and Glyde File Prep on the bond strength of MTA-dentin.

The purpose of this study was to evaluate the effects of sodium hypochlorite (5.25%), chlorhexidine (2%), and Glyde File Prep on the bond strengths of MTA-dentin in vitro. Standardized dentin disks were prepared and the central hole in each disk was filled with mineral trioxide aggregate (MTA). The specimens were randomly divided into four groups to be immersed in saline, 5.25% NaOCl, 2% chlorhexidine, and Glyde File Prep for 2 hours. The bond strengths of MTA-dentin were measured with a material testing system (MTS) and the fractured surfaces on the root walls were observed by scanning electron microscopy. Compared with the control group, the bond strengths were significantly lower in Glyde File Prep group (p < 0.05) and there was no significant difference in the chlorhexidine group or in the NaOCl group (p > 0.05). This study suggested that Glyde File Prep could negatively affect the bond strengths of MTA-dentin.

Aluminum Compounds↗
PubMed2006

Comparison of defects in ProFile and ProTaper systems after clinical use.

The purpose of this study was to compare the incidence and mode of instrument separation of the two nickel-titanium (NiTi) rotary systems that were used according to a predefined schedule of clinical use by the same group of operators. A total of 166 ProFile and 325 ProTaper instruments, discarded from this endodontic clinic over 17 months, was analyzed. The incidences of instrument separation were 7% for ProFile and 14% for ProTaper (p < 0.05). The proportion of unwinding defects was 5% in ProFile and 0.3% in ProTaper instruments (p < 0.01). Flexural fatigue was implicated in the majority of separations in both groups. The results of this study indicated that while ProTaper was more likely to separate without warning, ProFile tended to exhibit unwinding of flutes more frequently.

Dental Alloys↗
PubMed2006

Anti-gingivitis effect of a dentifrice containing bioactive glass (NovaMin) particulate.

BACKGROUND: The objective of this pilot clinical trial was to evaluate the anti-gingivitis and anti-plaque effects of a dentifrice containing bioactive glass (NovaMin) compared with a placebo control dentifrice in a 6 weeks clinical study. METHODS: The study design was a randomized, double-blinded, controlled clinical trial. One hundred volunteers took part in the study and were matched for plaque index (PLI), gingival bleeding index (GBI), age and gender. The protocol was reviewed and approved by the Ethical Committee of the University. The subjects received a supragingival prophylaxis to remove all plaque, calculus and extrinsic stain. Following the baseline examination, subjects were instructed to brush with their assigned dentifrice and toothbrush. The PLI and GBI were determined for the baseline and 6 weeks. The data were analysed using a repeated-measures anova conducted on the two dependent measures to compare the effect between the test and control group. RESULTS: Ninety-five subjects finished the study. The results showed that the PLI (baseline=1.54, 6 weeks=1.29) and GBI (baseline=1.14, 6 weeks=0.47) were significantly reduced, respectively, over the 6 weeks period in the test group (p<0.001 for each measure). There was a 58.8% reduction in gingival bleeding and a 16.4% reduction in plaque growth. There was no difference of the PLI (baseline=1.60, 6 weeks=1.57) and GBI (baseline=1.18, 6-week=1.02) over the 6 week period in the control group. CONCLUSION: This study demonstrated that a dentifrice containing NovaMin significantly improves oral health as measured by a reduction in gingival bleeding and reduction in supragingival plaque compared with a negative dentifrice over the 6 weeks study period.

Adult↗
PubMed2006

Expression of c-Src and comparison of cytologic features in cherubism, central giant cell granuloma and giant cell tumors.

Cherubism (CBM) and central giant cell granuloma (CGCG) of the jaw and giant cell tumor (GCT) of the long bone are clinically different diseases. Histologically, they are all multinucleated giant cell (MGC)-containing lesions. This study aims to evaluate the expression of c-Src and cytologic features in CBM, CGCG and GCT and to clarify whether there is a common mechanism underlying the formation of multi-nucleated giant cells (MGCs) in these lesions. Specimens and paraffin blocks were collected from patients with CBM (12 cases), CGCG (24 cases) and GCT (37 cases). Histomorpho-metric differences in MGCs were compared among the three types of lesions. The expression of c-Src by immunohistochemistry and in situ hybridization and the expression of TRAP by enzyme histochemical staining were examined. Expression of c-Src mRNA and protein, as well as TRAP staining, was detected in both MGCs and a fraction of mononuclear cells in all investigated lesions. There are no quantitative differences for cytologic features and c-Src expression among the lesions. The results suggested that CBM, CGCG and GCT have overlapping cytological features at the histological level, and c-Src may be involved in the formation of MGCs in the three different diseases.

Acid Phosphatase↗
PubMed2006

[A study of the physicochemical and biological properties of mutanase from Trichoderma harzianum].

OBJECTIVE: To determine the physicochemical properties of the mutanase of Trichoderma harzianum isolated from China and to study the influence of mutanase on the adherence of oral Streptococci and the structure of oral biofilms. METHODS: Six fungal strains belonging to Trichoderma were tested for mutanase production in the same cultural condition, the strain producing the highest mutanase activity was studied further and the pH and temperature optimum of the enzyme was determined. The RT-PCR method was used to obtain the gene coding for mutanase and the product was cloned to pMD18-T simple vector for sequencing. Inhibition effects of mutanase on the adherence of Streptococcus sobrinus OMZ176, Streptococcus sobrinus 6715, Streptococcus mutans MT8148 were studied by adherence test. The optical sectioning of biofilms with or without mutanase supplementation were analyzed by confocal laser scanning microscopy (CLSM). RESULTS: The highest enzymatic activity was achieved by Trichoderma harzianum Th1, the maximum activity was at pH 5.5 and at 40 degrees C. The nucleotide sequence was 92% homology with that of a known gene coding a mutanase (GenBank accession No. AJ243799). The adherence of Streptococcus sobrinus OMZ176, Streptococcus sobrinus 6715, Streptococcus mutans MT8148 was significantly inhibited by mutanase. Compared with control, the biofilms with mutanase supplementation had lower height and sparser structure. CONCLUSIONS: The mutanase from Trichoderma harzianum Th1 can inhibit the adherence of oral Streptococci and had an influence on the structure of oral biofilms.

Bacterial Adhesion↗
PubMed2006

[Expression pattern and level of cytotoxic T lymphocyte-associated antigen-4 targeted anti-caries plasmids in eukaryotic cells].

OBJECTIVE: To investigate and compare the expression pattern and level of targeted anti-caries plasmids encoding different-size antigens in eukaryotic cells. METHODS: The A-P fragment of PAc (surface protein antigen) was removed from pGJA-P encoding the signal peptide, extracellular domains of human CTLA-4, human Ig hinge, CH2 and CH3 domains, A-P fragment of PAc and GLU (glucan binding domain) region of GTF-I of Streptococcus mutans, to obtain the plasmid pGJGLU. pCI vector skeleton of pGJA-P or pGJGLU was replaced by pVAX1 to construct plasmids pGJA-P/VAX and pGJGLU/VAX. CTLA4-Ig-GLU fragment was removed from pGJGLU and inserted into the vector pEGFP-N1 to obtain the recombinant plasmid pGJGLU/GFP. The CHO cells were transfected with those plasmids by using liposome and the expression of fusion protein was observed with fluorescence microscope. ELISA was used to detect the expression level of fusion proteins in cultured supernatants. RESULTS: Specific vesicles with green fluorescence could be observed in the CHO cells transfected with pGJGLU/GFP. The recombinant fusion protein could be detected in the cultured supernatants of CHO cells transfected with pGJA-P/VAX, pGJGLU/VAX and pGJGLU/GFP, of which the concentration was different. The highest concentration of recombinant fusion protein was observed in the supernatants of CHO cells transfected with pGJGLU/VAX. CONCLUSIONS: CTLA-4 targeted fusion protein could be expressed and secreted by eukaryotic cells. The size of antigen may affect the expression level of CTLA-4 targeted anti-caries DNA vaccine.

Animals↗