Upregulation of microRNA-224 is associated with aggressive progression and poor prognosis in human cervical cancer.

OBJECTIVE: Accumulating evidence for differential expression of microRNA-224 (miR-224) in various types of human cancer suggests that it may be play a crucial role in tumor biology. The previous microarray detection also shown that miR-224 was one of miRNAs with significant upregulation in cervical cancer tissues relative to adjacent normal tissues. However, little is known about the function of miR-224 in human cervical cancer. The aim of this study was to investigate the clinical significance of miR-224 expression in cervical cancer. METHODS: MiR-224 expression in 126 pairs of fresh human cervical cancer and adjacent normal tissues was measured by real-time quantitative RT-PCR assay. RESULTS: miR-224 expression was significantly upregulated in cervical cancer tissues when compared with corresponding adjacent normal tissues (P<0.001). It was also significantly higher in the cancerous tissues of patients with advanced FIGO stage cervical cancer than those with early FIGO stage (P=0.02). In addition, miR-224 was expressed at significantly higher levels in lymph node metastasis-positive patients than in lymph node metastasis-negative patients (P=0.008). Moreover, we found that lesser differentiated tumors expressed higher miR-224 (P=0.03). Finally, there were sufficient evidence to confirm its value in the status of vascular invasion (P=0.01) and human papillomavirus (HPV) infection (P=0.02) in cervical cancer. More importantly, Kaplan-Meier analysis showed that cervical cancer patients with high miR-224 expression tend to have shorter overall survival. In multivariate analysis stratified for known prognostic variables, miR-224 was identified as an independent prognostic marker. CONCLUSION: Our data indicated that miR-224 upregulation was associated with aggressive progression and poor prognosis in cervical cancer. MiR-224 was identified for the first time as an independent marker for predicting the clinical outcome of cervical cancer patients. VIRTUAL SLIDES: The virtual slide(s) for this article can be found here: http://www.diagnosticpathology.diagnomx.eu/vs/2170449349527493.

[Establishment and evaluation of the in vitro dynamic biofilm model].

PURPOSE: To establish a dynamic model which could simulate the ecologic environment of oral cavity and study the cariogenicity of oral biofilm, continuously observe the formation of oral biofilm. METHODS: The fermental vessel and chemostat were designed according to the purpose of the study. Four strains of oral bacteria, namely Streptococcus mutans, Streptococcus sanguis, Lactobacillus rhamnosus and Actinomyces naeslundii, were inoculated in the fermenter. The hydroxyapatite (HA) discs and glass slides were put in the chemostat. The temperature, oxide pressure, pH, dilution rate, circulation rate and substrate of the chemostat were carefully modulated. Distilled water and 25mM sucrose solution were used to test the stability of the system. At the beginning of the model establishment, the anabiosis bacteria were inoculated in fermenter full of fresh artificial saliva with a dilution rate of 10%. After the growth of bacteria in the fermenter was stable, the four-organism bacterial consortium was inoculated in the chemotat for 24 hours together with fresh artificial saliva (v/v=1:9). The organisms in planktonic phase were examined everyday. When the populations of consortium got stable(about 72 hours), the test solution was pulsed in the chemostat every 12 hours for 5 days. The HA discs and glass slides were observed every 24 hours for five times. The data was analyzed using SPSS 10.0 software package. Dunnet t test was used to compare the difference between the two groups at the level of alpha=0.05. RESULTS: The dynamic model was successfully established on oral biofilm study. With the pulse of sucrose solution, the environment in the chemostat simulated the cariogenic environment in nature, and all data namely the bacteria population, the biofilm microstructure changed with solution pulse. CONCLSUIONS: The model established is proved to be stable and the parameters in the model could be successfully controlled. The model fulfills the dynamic observation of formation of biofilm and caries lesion in vitro.

[The effect of coaggregation of A.viscosus and P.gingivalis on the adherence of A.viscosus to hydroxyapatite].

PURPOSE: To examine the effect of coaggregation of A.viscosus and P.gingivalis on the adherence of A.viscosus to saliva-coated hydroxyapatite(S-HA). METHODS: The suspensions of A.viscosus and P.gingivalis were rotated and dropped on cover slips to visualize the coaggregation under scanning electron microscope(SEM). Different concentrations of P.gingivalis were mixed with A.viscosus radiolabeled with 10 uCi of [methyl-(3)H] thymedine per milliliter, then rotated for periods up to 1.5 hours at room temperature and the numbers of absorbed A.viscosus cells were determined by liquid scintillation. A.viscosus alone was used as the control, and its adhesion percent was set for 100%. One-way ANOVA with SPSS10.07 software package was used to analyze the effect of P.gingivalis on adherence of A.viscosus. RESULTS: Several cells of P.gingivalis could aggregate on the surface of A.viscosus. The adherence of A.viscosus to S-HA was promoted slightly when the concentration of P.gingivalis was rather small, then further increase in concentration of P.gingivalis resulted in a steady decline in the number of adherent A.viscosus, and the difference was significant (P<0.05). CONCLUSION: These results show that the adherence of A.viscosus to S-HA could be influenced by coaggregation of P.gingivalis and A.viscosus.

[The relationship in growth between A.actinomycetemcomitans and cariogenic bacteria in vitro].

PURPOSE: To investigate the correlation in growth between A.actinomycetemcomitans and cariogenic bacteria of S.mutans, L.acidophilus A.naeslundii A.viscosus in vitro. METHODS: Using improvement agar diffusion method and dual-species (A.actinomycetemcomitans with each of cariogenic bacteria) incubation in BHI broth, we studied the relationship between A.actinomycetemcomitans and 4 kinds cariogenic bacteria in growth. The characteristic and percentage of A.actinomycetemcomitans in dual-species biofilms were detected with SEM and CFU(colony forming units).The data were analyzed for significance using an independent two-sample t test with SPSS 10.0 software package. RESULTS: The agar diffusion essay showed that A.actinomycetemcomitans had no effect on the growth of S.mutans, L.acidophilus A.naeslundii and A.viscosus. While these 4 kinds of cariogenic bacteria could inhibit the growth of A.actinomycetemcomitans. The ratio of A.actinomycetemcomitans in the dual-species suspension decreased gradually.In dual-species BHI broth, the proportion of A.actinomycetemcomitans cultured alone ahead of 12 hours decreased as well, which came to 0 at 24-hour in S.mutans and L.acidophilus groups. There was significant difference between different time groups(P<0.05).The single A.actinomycetemcomitans was failed to form three-dimensional biofilm and just a small quantity of cells accumulated and adhered. On the contrary, the 4 kinds of single cariogenic bacteria could form mature biofilms respectively by themselves at 48-hour,of which the appearance of biofilms had no apparent change to that of single cariogenic bacteria after mixing A.actinomycetemcomitans. CFU of dual-species biofilms indicated that the percentage of A.actinomycetemcomitans in biofilms decreased gradually by changing medium per 12 hours. There were significant difference among the three time spots(P<0.05). CONCLUSION: The study shows that S.mutans, L.acidophilus A.naeslundii and A.viscosus could inhibit the growth of A.actinomycetemcomitans in vitro.

[Investigation of influence on apical sealability generated by root canal sealer placement].

OBJECTIVE: To investigate the influence of sealer placement on apical sealability in root canal treatment. METHODS: 100 extracted single root canal teeth were selected. All canals were prepared by manual Protaper instrument in a step-back way. The samples were divided into 5 groups randomly. A group: 30 samples, sealer placement by chief gutta percha; B group: 30 samples, sealer placement by K file; C group: 30 samples, sealer placement by spreader; D group: 5 samples, a positive control; E group: 5 samples, a negative control. There were 2 subsets in each experimental group which were obturated by lateral gutta percha with or without sealer. Glucose oxidase method was used to measure the apical leakage at the 1st 2nd, 4th, 7th, 10th, 15th, 20th, 25th, 30th day of the experiment. RESULTS: Apical sealability varied with different sealer placement methods (F=4.832, P=0.001). Sealer placement by chief gutta percha (A group) had the best instant apical sealability. However, lateral gutta percha with or without sealer didn't affect the apical sealibility. CONCLUSION: Placing the same kind sealer in different ways can affect the apical sealability. There were no significant differences of the apical leakage no matter the lateral gutta percha with or without sealer. In order to get better instant apical sealability and simplify the clinic operation, placing the sealer with a chief gutta percha while the lateral gutta percha without sealer is recommended.

[Quality evaluation on Chinese clinical research literatures about dental caries in 1950-2005].

OBJECTIVE: The purpose of this study is to evaluate the quality level of Chinese clinical research about dental caries in 1950-2005. METHODS: The Chinese clinical research literatures about dental caries in 1950-2005 were collected. All the literatures were evaluated by Jadad scale. The score of Jadad scale was form 0 to 5. Score 2 and below was poor quality literature, and score 3 and more was high quality literature. The full marks of Jadad scale was 5. RESULTS: 3,201 clinical research papers about dental caries were collected, in which 46 articles were high quality literature. In 3,201 papers, random allocation methods were mentioned in 142 papers, double-blind measure were performed in 26 papers, the withdrawn and missing cases were described in 256 papers. CONCLUSION: The high quality literature of Chinese clinical research about dental caries in scientific research design is less. The scientific research design should be strength to enhance the total quality of Chinese clinical research about dental caries.

[Effect of A.viscosus on growth of P. gingivalis in vitro].

PURPOSE: To investigate the effect of A. viscosus on growth of P. gingivalis in vitro. METHODS: Groups as single-species(A.viscosus or P.gingivalis) and dual-species (A.viscosus and P.gingivalis) were incubated in BHI broth anaerobically at 37 degrees C, and growth curve of each group was monitored for 48 hours; Meanwhile the dual-species cultures of 2-hour interval were taken and the dilution was inoculated on BHI blood agar plates for 72 hours. The percentage of P. gingivalis was detected. BHI blood agar plates inoculated with P. gingivalis were prepared, and different concentrations of A. viscosus and its degerming supernatant were inoculated on the above plates in dropping method and incubated anaerobically for 72 hours. Zones of inhibition were measured and the data were analysed with SPSS 10.0 software package for one-way ANOVA. RESULTS: A. viscosus was in logarithmic phase of growth at 2-hour and reached plateau at 8-hour. P. gingivalis entered logarithmic phase at 12-hour and reached plateau at 32-hour. Co-culture group was in logarithmic phase of growth at 2-hour and reached plateau at 12-hour. The percentage of P.gingivalis decreased gradually on BHI plates (P<0.05) and at 8-hour no P. gingivalis colony was found. The average diameters (mm) of inhibition zones were 19.3, 17.4, 13.2, 9.8 when the concentration of A. viscosus applied was 1 x 10(9), 10(8), 10(7), 10(6) CFU/ml, respectively. There was significance difference among the four groups (P<0.05). The supernatant of A. viscosus didn't show restrain on plates with P. gingivalis. CONCLUSION: The study suggests that A. viscosus could inhibit the growth of P. gingivalis by nutrition competition in vitro.

[Effect of chemical compounds of Galla chinensis on enamel surface rehardening in vitro].

OBJECTIVE: To evaluate the effect of chemical compounds extracted from Galla chinensis on enamel surface rehardening in vitro. METHODS: Sixty bovine enamel blocks with early carious lesions were randomly divided into six groups: group1 treated NaF (positive control); group2 with GCE; group3 with GCE-B; group4 with GCE-B1; group5 with GCE-B2 and group6 with deionized water (negative control). The lesions were subjected to a pH-cycling regime for 12 days. Surface enamel microhardness was measured on the enamel blocks before and after demineralization. After pH-cycling, and the percentage of surface microhardness recovery (SMHR) was calculated. RESULTS: Obvious increase of the surface hardness of the enamel was observed in all the treatments except GCE-B2 and deionized water (P < 0.05). CONCLUSIONS: The present study demonstrates the potential of the three GCEs (GCE, GCE-B and GCE-B1) to effect net rehardening of artificial carious lesions under dynamic pH-cyclic conditions.

[Morphology of cross-sectioned root canal in Chinese mandibular permanent incisors].

OBJECTIVE: To identify morphological features of cross-sectioned root canal in Chinese mandibular permanent incisors. METHODS: Twenty mandibular permanent incisors were selected in this study. The tooth roots were embedded in resin and transversely sectioned with a low-speed diamond saw. The number of root canal and the morphology and isthmus of the root canal were observed under a stereo-microscope, which included the measure of the canal diameter. RESULTS: The double root canal comprised 22.5%, 30.0%, and 15.0% in crown third, middle third, and apical third root canals of the mandibular permanent incisors, respectively. The long oval canal comprised 44.8%, 77.0%, and 44.5% in crown third, middle third, and apical third root canals, respectively. The canal isthmus comprised 62.5%, 75.0%, and 48.7% in crown third, middle third, and apical third root canals, respectively. The diameter of buccal-lingual canal was at least 2 times of the diameter of mesial-distal canal. CONCLUSION: The cross-sectioned root canal morphology in Chinese mandibular permanent incisors varies considerably. But most have long oval and canal isthmus, which imposes a great challenge for root canal therapy.

[Effect of light-emitting diode curing light and halogen light on microleakage of extracted teeth].

OBJECTIVE: To evaluate the effect of light-emitting diode (LED) curing light and Halogen dental curing light on the microleakage of Clearfil AP-X composite restorations and to provide evidence for clinical use of LED curing light. METHODS: Class V cavities were prepared in 73 freshly extracted teeth. The teeth were randomly divided into two groups being exposed to light-emitting diode curing light MORITA PENCURE and halogen light 3M ESPE Elipar 2500 respectively, and then treated with thermocycling (500 cycles, 5-55 degrees C), section and dyeing. The amounts of dye infiltration and marginal seal were examined by stereomicroscope and scanning electron microscope (SEM) respectively. RESULTS: No significant differences were found in the amount of dye infiltration shown in the stereo-photomicrograph between the two groups. However, the SEM revealed better marginal seals of those teeth exposed to LED curing light. CONCLUSION: The LED curing light may be able to achieve the same or better effect on reducing microleakage compared with the Halogen dental curing light. Further studies are needed.

Effects of cecropin-XJ on growth and adherence of oral cariogenic bacteria in vitro.

BACKGROUND: Cecropin-XJ belongs to cecropin-B, which is the most potent antibacterial peptide found naturally. The aim of this study was to investigate the effects of cecropin-XJ on growth and adherence of oral cariogenic bacteria. METHODS: Four oral cariogenic bacteria (Streptococcus mutans, Lactobacillus acidophilus, Actinomyces viscosus and Actinomyces naeslundii) were chosen for this experiment. The minimal inhibitory concentrations (MICs) and reductive percent of bacterial growth were used to assay the antibacterial activity of cecropin-XJ. Mammalian cytotoxicity of cecropin-XJ was tested with human periodontal membrane fibroblasts by tetrazolium (MTT) colorimetric assay. The bacterial morphological changes induced by cecropin-XJ were examined on scanning electron microscope (SEM). The influence of cecropin-XJ on bacterial adhesion to saliva-coated hydroxyapatite (S-HA) was measured by scintillation counting. RESULTS: The MICs of cecropin-XJ for inhibition of the growth of four bacteria ranged from 4.0 to 42.8 micromol/L with the highest susceptible to A. naeslundii and the lowest susceptible to L. acidophilus. At pH 6.8, 5.5 and 8.2, 1/2 MIC of cecropin-XJ reduced the number of viable bacteria by 40.9%, 67.8% and 32.8% for S. mutans and by 28.1%, 57.2% and 37.9% for L. acidophilus. The activities against S. mutans and L. acidophilus increased at pH 5.5 compared with pH 6.8 (P < 0.01, respectively). In present of 50% saliva, 1/2 MIC of the peptide decreased the direct count of viable cells by 29.2% and 14.4% for S. mutans and L. acidophilus, respectively (P < 0.01 and P > 0.05, respectively), whereas almost no reduction counts were detected in the presence of 20% serum for both bacteria (P > 0.05, respectively). Mammalian cytotoxicity of cecropin-XJ from 1.0 to 100 micromol/L exhibited no cytotoxicity against human periodontal membrane fibroblasts (P > 0.05). Bacterial morphological changes induced by MIC of cecropin-XJ examined on SEM showed cell surface disruption. Furthermore, the ability of A. naeslundii adhesion to S-HA decreased significantly with MIC of cecropin-XJ for 10 and 20 minutes (P = 0.001 and 0.000, respectively), and S. mutans, A. viscosus to S-HA decreased significantly with MIC of cecropin-XJ for 20 minutes (P = 0.000, respectively). CONCLUSIONS: Cecropin-XJ exhibited bactericidal action against cariogenic pathogens, and the antibacterial activity enhanced in the acid environment. The results also demonstrate that cecropin-XJ prevents S. mutans and actinomyces adsorption to S-HA. These findings suggest that Cecropin-XJ may have potential to prevent caries.

[Expression of matrixmetalloproteinase-8 on the bell-stage in human and rat tooth development].

OBJECTIVE: To study the expression of MMP-8 in human and rat tooth development. METHODS: Immunohistochemistry was used to detect the localization of MMP-8 protein while in situ hybridization was used to examine the expression of MMP-8 mRNA. RESULTS: The expression of MMP-8 protein was localized in odontoblast and dentin matrix at the later bell stage in human tooth germ. The dentin was denser close to the pulp cavity. The expression of MMP-8 mRNA was found in very few polarized odontoblast at the early bell stage and all polarized odontoblast at the later bell stage in rat tooth germ. CONCLUSION: The results suggested that MMP-8 involved in dentin matrix rebuilding in the process of dentin formation in human and rat dental development.

[An immunohistochemical study of the effects of excessive fluoride on type I collagen in rat developmental dentine].

OBJECTIVE: To study the effects of excessive fluoride on type I collagen in rat developmental dentine. METHODS: Eighty SD rats, 5 days old, were divided into experimental and control groups, 40 in each group. The experimental group received subcutaneous injection of 0.2% NaF every 4 days (the dose was 2 mg NaF per kg body wt). The same volume of 0.9% NaCl was used in the control. Twenty rats in each group were killed 4 days after the second and the seventh injection respectively. The expression of type I collagen was assayed with immunohistochemical technique. RESULTS: 4 out of 20 rats after two injections showed abnormal distribution of type I collagen (dense stain of collagen in the odontoblast, aggregation of collagen in the dentine and disordered arrangement of collagen in the predentine; All 20 rats after seven injections showed abnormal distribution of type I collagen. CONCLUSION: Excessive fluoride may affect the metabolism of type I collagen in rat developmental dentine.