Role of telomerase in the tumour microenvironment.

Telomeres are specialized genomic structures that protect chromosomal ends to maintain genomic stability. Telomeric length is primarily regulated by the telomerase complex, essentially consisting of an RNA template (TERC), an enzymatic subunit (telomerase reverse transcriptase, TERT). In humans, telomerase activity is repressed during embryonic differentiation and is absent in most somatic cells. However, it is upregulated or reactivated in 80%-90% of the primary tumours in humans. The human TERT (hTERT) plays a pivotal role in cellular immortality and tumourigenesis. However, the molecular mechanisms of telomerase functioning in cancer have not been fully understood beyond the telomere maintenance. Several research groups, including ours, have demonstrated that hTERT possesses vital functions independent of its telomere maintenance, including angiogenesis, inflammation, cancer cell stemness, and epithelial-mesenchymal transformation (EMT). All these telomere-independent activities of hTERT may contribute to the regulation of the dynamics and homeostasis of the tumour microenvironment (TME), thereby promoting tumour growth and development. Cancer progression and metastasis largely depend upon the interactions between cancer cells and their microenvironment. In this review, the involvement of TERT in the tumour microenvironment and the underlying implications in cancer therapeutics have been summarized.

[Development of a Questionnaire Measuring Sexual Mental Health of Tibetan University Students].

OBJECTIVE: To develop a questionnaire measuring sexual mental health of Tibetan university students. METHODS: A draft questionnaire was developed with reference to the Sexual Civilization Survey for University Students of New Century and other published literature, and in consultation with experts. The questionnaire was tested in 230 students. Exploratory factor analyses with principal component and varimax orthogonal rotation were performed. Common factors with a > 1 eigenvalues and ≥ 3 loaded items (factor loading ≥ 0.4) were retained. Items with a < 0.4 factor loading, < 0.2 commonality, or falling into a common factor with < 3 items were excluded. The revised questionnaire was administered in another sample of 481 university students. Cronbach's α and split-half reliabilities were estimated. Confirmatory factor analyses were performed to test the construct validity of the questionnaire. RESULTS: Four rounds of exploratory factor analyses reduced the draft questionnaire items from 39 to 34 with a 7-factor structure. The questionnaire had a Cronbach's α of 0.920, 0.898, 0.812, 0.844, 0.787, 0.684, 0.703, and 0.608, and a Spearman-Brown coefficient of 0.763, 0.867, 0.742, 0838, 0.746, 0.822, 0.677, and 0.564 for the overall questionnaire and its 7 domains, respectively, suggesting good internal reliability. The structural equation of confirmatory factor analysis fitted well with the raw data: fit index χ²/df 3.736; root mean square residual (RMR) 0.081; root mean square error of approximation (RMSEA = 0.076; goodness of fit index (GFI) 0.805; adjusted goodness of fit index (AGFI) 0.770; normed fit index (NFI) = 0.774; relative fit index (RFI) 0.749; incremental fit index (IFI) 0.824; non-normed fit index (NNFI) = 0.803; comparative fit index (CFI) = 0.823; parsimony goodness of fit index (PGFI) = 0.684; parsimony normed fit index (PNFI) = 0.698; parsimony comparative fit index (PCFI) = 0.742, suggesting good construct validity of the questionnaire. CONCLUSION: The Sexual Mental Health Questionnaire for Tibetan University Student has demonstrated good reliability and validity.

Morphological and functional characteristics of human gingival junctional epithelium.

BACKGROUND: This study aims to observe the morphological characteristics and identify the function characteristics of junctional epithelium (JE) tissues and cultured JE cells. METHODS: Paraffin sections of human molar or premolar on the gingival buccolingual side were prepared from 6 subjects. HE staining and image analysis were performed to measure and compare the morphological difference among JE, oral gingival epithelium (OGE) and sulcular epithelium (SE). Immunohistochemistry was applied to detect the expression pattern of cytokeratin 5/6, 7, 8/18, 10/13, 16, 17, 19, and 20 in JE, OGE and SE. On the other hand, primary human JE and OGE cells were cultured in vitro. Cell identify was confirmed by histology and immunohistochemistry. In a co-culture model, TEM was used to observe the attachment formation between JE cells and tooth surface. RESULTS: Human JE was a unique tissue which was different from SE and OGE in morphology. Similarly, morphology of JE cells was also particular compared with OGE cells cultured in vitro. In addition, JE cells had a longer incubation period than OGE cells. Different expression of several CKs illustrated JE was in a characteristic of low differentiation and high regeneration. After being co-cultured for 14 d, multiple cell layers, basement membrane-like and hemidesmosome-like structures were appeared at the junction of JE cell membrane and tooth surface. CONCLUSIONS: JE is a specially stratified epithelium with low differentiation and high regeneration ability in gingival tissue both in vivo and in vitro. In co-culture model, human JE cells can form basement membrane-like and hemidesmosome-like structures in about 2 weeks.

Chemokine C-C motif ligand 8 in periodontal ligament during orthodontic tooth movement.

OBJECTIVES: To investigate the roles of chemokine (C-C motif) ligand 8 (CCL8) in periodontal ligament during orthodontic tooth movement (OTM). METHODS: Bioinformatics analyzed 100 genes in human periodontal ligament cells that were most upregulated after 48 hours of mechanical stress, and these genes were classified through GO and KEGG databases. Nickel-titanium closed-coil springs were placed between right first molar and incisors to produce 20 cN of orthodontic force in eight-week-old male SD rats for 1 and 2 days, followed by immunohistochemical staining of CCL8. Human periodontal ligament fibroblasts (hPDLFs) were stimulated by 14% cyclic tension force (Flexcell FX-5000 T Tension System) or hypoxia conditions to mimic OTM for 1 and 2 days, then the resulting CCL8 were examined through ELISA. Scratching assay was performed by treating hPDLFs with different concentrations of CCL8 (1 ng/ml, 10 ng/ml, 100 ng/ml). The migration, proliferation, and adhesion abilities of 100 ng/ml CCL8-treated hPDLFs were also examined. qRT-PCR and western blot detected matrix metalloproteinase 3, periostin, and osteoprotegrin expressions of hPDLFs under 100 ng/ml CCL8. RESULTS: Bioinformatic analysis demonstrated that CCL8 was upregulated after applying mechanical stress for 48 hours. CCL8 secretion showed upregulation after 24 hours of OTM applicationsin vivo and in vitro. CCL8-treated hPDLFs showed significant positive effects on cell proliferation and matrix metalloproteinase 3. It also inhibited periostin and osteoprotegrin expressions. CONCLUSIONS: CCL8 was upregulated in periodontal ligament during initial stage of OTM. Although CCL8 in human periodontal ligaments showed no significant effects on cell migration ability, it did enhance cell proliferation and osteoclastogenesis.

[Growth factors promote the survival and proliferation of human spermatogonium stem cells in vitro].

OBJECTIVE: To study the effects of growth factors on the survival and proliferation of human spermatogonial stem cells (SSCs) in vitro. METHODS: SSCs were treated with the growth factors SCF, LIF and bFGF added to the culture, each at the concentrations of 0, 5, 10 and 20 microg/L and repeated three times. The survival time and proliferation rate of the cells were determined every 8-12 hours and their morphological features observed with the light microscope and electron microscope. RESULTS: The survival time and proliferation rate of the SSCs were significantly increased in the treated groups as compared with the control (P < 0.05). CONCLUSION: The growth factors SCF, LIF and bFGF can promote the survival and proliferation of SSCs in vitro.

The possibility of healing alveolar bone defects with simvastatin thermosensitive gel: in vitro/in vivo evaluation.

BACKGROUND: In this study, simvastatin (SVT) in situ gels were successfully produced by our group. METHODS: The preparations were characterized in the following aspects: in vitro gelation, drug release, stability and pharmacodynamics. RESULTS: In this study, drug content of prepared gels was found to be in the range between 89 and 92%. The pH value was in the range between 6.5 and 7.0. The gelation temperature of the prepared thermogelling solutions was 37°C. In vitro release showed that the release of SVT from in situ gels was slow with burst effects at an early stage. Researches indicated that intraorally slow release SVT in situ gels could effectively promote bone regeneration repair of alveolar bone defect. CONCLUSION: This drug delivery system could prove to be a novel form able to prolong the residence time and to control the release of drug when administered into the oral cavity.

A distinction between two instruments measuring dispositional mindfulness and the correlations between those measurements and the neuroanatomical structure.

The most widely used measurements of mindfulness are the Mindful Attention Awareness Scale (MAAS) and the Five Facet Mindfulness Questionnaire (FFMQ). However, controversies exist regarding the application of these scales. Additionally, the neural mechanisms of dispositional mindfulness havebecome a topic of interest. In the current study, we used surface-based methodology to identify the brain regions underlying individual differences in dispositional mindfulness in a large non-clinical sampleand compared the two instruments for measuring the dispositional mindfulness. The results indicated that theMAAS scores were significantly associated with increased greymatter volumes in the right precuneus and the significant association between the precuneus and depression symptomatology was mediated by MAAS scores. Regarding the FFMQ, the Describing, Nonjudging, and Nonreactivity facets were selectively associated with the cortical volume, thickness and surface area of multiple prefrontal regions as well as the inferior parietal lobule. Importantly, Describing mediated the association between the dorsolateral PFC volume and the cognitive reappraisal strategies of emotion regulation. These resultssuggested that the MAASwere mainly associated with self-awareness, while the FFMQ facets were selectively involved in emotion regulation, attention control and self-awareness. Therefore, this study characterized the differences in inter-individual variability between the two typical measurements of dispositional mindfulnessand the correlations between those measurements and imaging analyses.

Preparation and characteristics of thermoresponsive gel of minocycline hydrochloride and evaluation of its effect on experimental periodontitis models.

In this study, a thermoresponsive gel for minocycline (MCL) with chitosan/ß-glycerophosphate (C/ß-GP) was formulated and its characterization, in vitro release, stability, toxicity and pharmacodynamics were investigated. The formulation containing MCL was prepared by pouring the chitosan solution directly onto the sterilized drug powder and stirring before mixing with the ß-glycerophosphate (ß-GP) solution. The final preparations contained 0.5% (w/v) chitosan, 1.8% (w/v) ß-GP and 2% (w/v) MCL. The drug content of prepared gels was in the range of 92-99%, and the pH value of the optimized formulation was found to be 5.6-6.2. The gelation temperature of the prepared C/ß-GP thermogelling solutions was 37 °C. Color, consistency, pH, viscosity and drug content of the in situ gels were found to be consistent, and no signs of separation and deterioration were observed over a period of 90 d. In vivo studies showed that rats' liver and kidney tissue sections were normal, with no structural damage. The constituents of the in situ gels formulation had a well-sustained release efficacy on the animal model of periodontitis.

Transforming growth factor-beta1 inhibits tissue engineering cartilage absorption via inducing the generation of regulatory T cells.

The objective of the present study was to explore the mechanisms of transforming growth factor (TGF)-ß1 inhibiting the absorption of tissue engineering cartilage. We transfected TGF-ß1 gene into bone marrow mesenchymal stem cells (BMMSCs) and co-cultured with interferon (IFN)-γ and tumour necrosis factor (TNF)-α and CD4(+) CD25(-) T lymphocytes. We then characterized the morphological changes, apoptosis and characterization of chondrogenic-committed cells from TGF-ß1(+) BMMSCs and explored their mechanisms. Results showed that BMMSCs apoptosis and tissue engineering cartilage absorption in the group with added IFN-γ and TNF-α were greater than in the control group. In contrast, there was little BMMSC apoptosis and absorption by tissue engineering cartilage in the group with added CD4(+) CD25(-) T lymphocytes; Foxp3(+) T cells and CD25(+) CD39(+) T cells were found. In contrast, no type II collagen or Foxp3(+) T cells or CD25(+) CD39(+) T cells was found in the TGF-ß1(-) BMMSC group. The data suggest that IFN-γ and TNF-α induced BMMSCs apoptosis and absorption of tissue engineering cartilage, but the newborn regulatory T (Treg) cells inhibited the function of IFN-γ and TNF-α and protected BMMSCs and tissue engineering cartilage. TGF-ß1not only played a cartilage inductive role, but also inhibited the absorption of tissue engineering cartilage. The pathway proposed in our study may simulate the actual reaction procedure after implantation of BMMSCs and tissue engineering cartilage in vivo.

Displacement of a dental implant into the maxillary sinus after internal sinus floor elevation: report of a case and review of literature.

BACKGROUND: Dental implant placement in the posterior maxilla may be complicated by implant migration into the maxillary sinus. PURPOSE: To report the clinical and radiological characteristics of a patient who experienced dental implant displacement into the maxillary sinus following sinus floor elevation, and to compare our findings with those of other published reports of the displacement of dental implants. MATERIALS AND METHODS: Implant placement and maxillary sinus elevation were performed simultaneously. The location of the displaced implant was monitored for 8 years, until the ectopic implant was surgically removed using the lateral window approach. The contributing factors, treatment modality, and clinical outcome for our patient were compared with those of patients reported in the literature. RESULTS: The clinical characteristics of our case were similar to those of patients with displaced implants who were also asymptomatic for long periods. The clinical outcome of our case was consistent with that of patients who underwent similar surgeries. CONCLUSIONS: Transnasal endoscopic removal of an ectopic implant may be suitable in cases in which the ectopic implant is accessible. Transoral direct approaches are adequate in most cases in which endoscopic approaches may be confounded. The bony-window transoral technique may allow the removal of large implants.

Sentrin/small ubiquitin-like modifier-specific protease 5 protects oral cancer cells from oxidative stress-induced apoptosis.

The aim of the present study was to investigate the role of sentrin/small ubiquitin-like modifier (SUMO)-specific protease 5 (SENP5) in oral squamous cell carcinoma (OSCC), as the overexpression of SENP5 has been observed in 31 OSCC tissue specimens. CAL-27 OSCC cells were used for in vitro measurements. The distribution of SENP5 was visualized using immunohistochemistry and H2O2-induced oxidative stress, and the effects of SENP-small interfering RNA on SENP5 were analyzed via western blotting. The apoptotic rates of the CAL-27 cells during oxidative stress and SENP5 silencing were estimated using flow-cytometry, and the mitochondrial structures were analyzed using a mitochondria tracker. The SENP5 protein was localized in the nuclei and cytosols of the CAL-27 cells, and incubation with 100 µm H2O2 for >1 h led to its stabilization. Incubation with H2O2 alone had no effect on the CAL-27 cells, however, a combination of H2O2 and SENP5 silencing led to enhanced apoptotic rates (P<0.001). Analysis of the mitochondrial structures revealed that H2O2 alone enhanced mitochondrial network formation, whereas the combination of H2O2 and SENP5 silencing led to mitochondrial fragmentation in the CAL-27 cells. The overexpression of SENP5 partly localized in the cytosol of the OSCC cells. Mild oxidative stress stabilized the SENP5 protein in the CAL-27 cells, and only the combination of SENP5 silencing and H2O2 application led to mitochondria fragmentation and a significant increase in cell apoptosis. Therefore, SENP5 protected the OSCC cells from oxidative stress-induced apoptosis.

[Evaluation of three-dimensional changes after sinus floor augmentation with DBBM].

PURPOSE: The objective of present study was to assess the dimensional stability of the grafting material DBBM (Bio-oss) after maxillary sinus floor augmentation with spiral computed tomography (SCT) scans and 3D reconstruction. METHODS: Two postoperative SCT scans were available from 12 patients who had undergone maxillary sinus lift procedures. CT scan was taken at 2 week after surgical intervention and 6 months later, respectively. A total of 12 maxillary sinuses were augmented with 100% DBBM before implant insertion by lateral antrostomy in a staged approach. The augmentation volume was calculated using the SurgiCase CMF5.0 software. Data were calculated by Stata10 software package. RESULTS: The mean volume of the graft was reduced by 19.40%. Specifically, the reduction reached 0.29% in the buccal-palatal direction, 5.87% in the mesial-distal dimension, and 14.32% in vertical dimension. CONCLUSIONS: This study confirmed that the volume of DBBM has a certain amount of reduction within 6 months after sinus floor augmentation. The reduction in vertical direction is most severe.

Double-barrel vascularised fibula graft in mandibular reconstruction: a 10-year experience with an algorithm.

BACKGROUND: This retrospective study aims to report an algorithm to assist surgeons in selecting different modes of the double-barrel vascularised fibula graft for mandibular reconstruction. METHODS: A total of 45 patients who underwent reconstruction of mandibular defects with different modes of the double-barrel vascularised fibula graft were reviewed. Our algorithm for deciding on any one of the different modes for different mandibular defects is influenced by factors including history of radiotherapy, the length of mandibular body defect and the need to preserve the inferior mandibular border. Post-operative functional outcomes included diet type and speech, and aesthetic results gained at post-operative 2 years. Patients with implant-borne prosthetic teeth underwent assessment of their masticatory function. RESULTS: There were four modes of mandibular reconstruction according to our algorithm, which included double-barrel vascularised fibula graft (n=21), partial double-barrel fibula graft (n=11), condylar prosthesis in combination with partial/double-barrel fibula graft (n=11), and double-barrel fibula onlay graft (n=2). Flap survival in all patients was 97.78%. Good occlusion, bony unions and wound closures were observed in 44 patients. Eleven patients received dental implantation in the transplanted fibula at post-operative 9-18th months. One patient wore removal partial dentures. For 11 patients with implant-borne prosthetic teeth, the average post-operative ipsilateral occlusal force was 41.5±17.7% of the contralateral force. Good functional and aesthetic results were achieved in 38 patients with more than 2 years of follow-up, including regular diet, normal speech and excellent or good appearance, especially for patients with dental rehabilitation. CONCLUSION: Good aesthetic and functional results can be achieved after dental rehabilitation by following our algorithm when choosing the different modes of double-barrel vascularised fibula graft for mandibular reconstruction.

[Study on the microstructure and ESR dosimetry of tetracycline-stained teeth with SEM observation and ESR measurement].

PURPOSE: To compare the microstructure and ESR dosimetry between tetracycline-stained teeth and normal teeth by means of scanning electron microscopy (SEM) and electron spin resonance (ESR) dosimeter. METHODS: Ten first or second premolars of tetracycline-stained teeth and ten normal teeth extracted for adult orthodontic persons were collected. The enamel on the surface and the dentine on the cross section of both type of teeth were observed with SEM. The ESR signal of teeth components (enamel and dentine) was evaluated by X-band ESR spectroscopy. RESULTS: Compared with normal teeth, the enamel of tetracycline-stained teeth was of porosity and the enamel prisms were irregular. The dentinal tubules and dentinal matrix also showed obvious difference between the two type of teeth. The X-band ESR spectrum of tetracycline-stained teeth was different from normal teeth. CONCLUSION: The microstructure and the native radicals have significant effect on the tetracyclines deposited in the teeth.

[Measurement of the height and width of residual alveolar crests in low-set maxillary sinus patients with missing upper molar].

PURPOSE: Using spiral computed tomography and Simplant software to measure the width and height of residual alveolar crest of agomphious upper molar region at different levels around bottom of low-set maxillary sinus. To evaluate the impact of sex, age, agomphious duration, and cause of tooth extraction on the width and height of residual alveolar crest. METHODS: Forty-three patients with missing uppers molar and residual alveolar bone height being 4 to 6mm showed by panoramic radiographs were scanned by spiral computed tomography. 3D model of the alveolar crest and maxillary sinus were reconstructed using the images from CT scan and Simplant software. The height and width of the residual alveolar crest of agomphious upper molar region at different levels around bottom of maxillary sinus were measured. The data was analyzed with SPSS16.0 software package for Student's t test, analysis of variance(ANOVA) and Kruskal-Wallis H test. RESULTS: (1)The mean distance between the top of residual alveolar crest and the floor of sinus was (5.26±0.58)mm. (2)The difference between the width of internal bone wall and that of external bone wall at different levels above the bottom of maxillary sinus was significant(P<0.01), except for agomphious upper second molar at 3.75mm. (3)The height of residual crest and width of sinus floor decreased remarkably with age and agomphious duration(P<0.01) while the width of sinus lateral walls didn't change so much with them(P>0.05). (4)Height of residual crest of the tooth extracted due to periodontitis was obviously lower than that of the tooth extracted due to residual root(crown) or crown fracture(P<0.01). CONCLUSIONS: The height and width of residual crest change significantly with age, agomphious duration and causes of tooth extraction. However, the width of lateral walls above sinus floor do not change so much with those factors. The internal wall of maxillary sinus floor is wider than the external wall at agomphious molar. This anatomic feature may be taken into consideration during implantation. The site and direction of implant can be adjusted equally according to the age, agomphious duration and causes of tooth extraction, so that maxillary sinus augmentation can be avoided in part of patients with low-set maxillary sinus.

[Effects of different premolar extraction on lower third molar eruption].

PURPOSE: To analyze the effect of different premolar extraction on the position of the mandibular third molar during orthodontic treatment. METHODS: Cephalometric radiographs were taken before and after 2 years of treatment in 28 female patients selected from Department of Orthodontic, Ninth People's Hospital, School of Medicine, Shanghai Jiao Tong University. Treatment for 12 patients in group I included extraction of 4 second premolars,the other 16 patients in group II were treated with extraction of 4 first premolars. Modified sectional arch wire technique was used to redistribute the spaces.Change of the mandibular third molar position was valued by tracing. The data was analyzed using SAS6.12 software package for student's t test. RESULTS: The vertical change in the third molar position in group I and II was (4.58+/-1.85)mm and (0.21+/-1.11)mm (P<0.01), the horizontal change was (2.95+/-2.55)mm and (-0.03+/-1.74)mm (P<0.01), the mesio-angulation was decreased (-10.12+/-8.27) degrees and (-5.06+/-3.60) degrees (P<0.05),and the angle to the second molar decreased (-15.58+/-9.65) degrees and (-4.21+/-3.68) degrees (P<0.001), respectively. CONCLUSION: Second premolar extraction may increase the rates of movement of the third molar in horizontal and vertical direction and decrease the mesio-angulation and the angle to the second molar than first premolar extraction.