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Luo J.,Tianjin Medical University | Li Y.-N.,Tianjin Stomatological Hospital | Wang F.,Tianjin Medical University | Zhang W.-M.,Tianjin Medical University | Geng X.,Tianjin Medical University
International Journal of Biological Sciences | Year: 2010

A global DNA hypomethylation might activate oncogene transcription, thus promoting carcinogenesis and tumor development. S-Adenosylmethionine (SAM) serves as a major methyl donor in biological transmethylation events. The object of this study is to explore the influence of SAM on the status of methylation at the promoter of the oncogenes c-,myc H-ras and tumor-suppressor gene p16 (INK4a), as well as its inhibitory effect on cancer cells. The results indicated that SAM treatment inhibited cell growth in gastric cancer cells and colon cancer cells, and the inhibition efficiency was significantly higher than that in the normal cells. Under standard growth conditions, C-myc and H-ras promoters were hypomethylated in gastric cancer cells and colon cancer cells. SAM treatment resulted in a heavy methylation of these promoters, which consequently downregulated mRNA and protein levels. In contrast, there was no significant difference in mRNA and protein levels of p16 (INK4a) with and without SAM treatment. SAM can effectively inhibit the tumor cells growth by reversing the DNA hypomet hyl ation on promoters of oncogenes, thus down-regulating their expression. With no influence on the expression of the tumor suppressor genes, such as P16, SAM could be used as a potential drug for cancer therapy. © Ivyspring International Publisher.

Zhu Y.-P.,Tianjin Stomatological Hospital | Zhu Y.-P.,Tianjin Medical University | Li C.-Y.,Tianjin Medical University | Zhang L.-Y.,Tianjin Medical University
Rare Metals | Year: 2014

The corrosion resistance behavior of TA2 pure titanium processed by tungsten inert gas (TIG) welding was investigated in artificial saliva solution at 37 °C. By metallographic examination, electrochemical measurement technology, and electrochemical impedance spectroscopy (EIS), the corrosion resistance of the base metal (BM), heat-affected zone (HAZ), and weld metal (WM) were investigated. Metallographic examination experiments show that welding process would cause the growth of grain size. In addition, phase change happens in the HAZ and WM. The change of grain size and phase would influence the generation of the original passive film. The electrochemical tests show that the BM, HAZ, and WM are all equipped with good corrosion resistance. The welded joint shows a better corrosion resistance than the original TA2. It is shown that the BM with the lowest corrosion potential and the biggest corrosion current has a worse corrosion resistance than WM as well as HAZ. Silver (Ag) nanoparticles can be distributed on the WM zone of Ti uniformly. The WM zone of Ti with Ag coating considerably enhances the antibacterial activity of Ti implants. © 2014 The Nonferrous Metals Society of China and Springer-Verlag Berlin Heidelberg.

Wang H.W.,Tianjin Stomatological Hospital
Zhonghua kou qiang yi xue za zhi = Zhonghua kouqiang yixue zazhi = Chinese journal of stomatology | Year: 2012

To analyze the three-dimensional changes of pharyngeal airway in patients with skeletal Class III malocclusion after the combined orthodontic and orthognathic treatment. Twenty patients (9 males, 11 females) and 40 subjects with normal occlusion were involved in the study. Cone-beam computed tomography (CBCT) were performed on patients one week and six months after treatment. Raw data were reconstructed into three-dimensional model and sagittal and transversal measurements, cross sectional areas, partial and total volumes were computed. After treatment, the sagittal diameters of each section were significantly reduced by (2.7 ± 3.5), (3.0 ± 3.8), (2.7 ± 3.3) mm, respectively (P < 0.05). The transversal diameter of laryngopharyngeal airway constricted significantly by (4.8 ± 4.1) mm (P < 0.05). Cross sectional areas and volumes of each part in patients after surgery were significantly narrower compared with those of the controls. After combined therapy the pharyngeal airway space decreased.

Peng P.,China Medical University at Heping | Shen J.,Tianjin Stomatological Hospital | Dong J.-B.,Tianjin Medical University | Zhang Y.,China Medical University at Heping
International Journal of Oral and Maxillofacial Surgery | Year: 2014

The aim of this study was to evaluate the association of preoperative plasma fibrinogen levels with clinico-pathological parameters and disease-free survival in patients with oral tongue squamous cell carcinoma (OTSCC). We retrospectively studied 76 patients with OTSCC who underwent a partial glossectomy only, at a single centre, between 1996 and 2007. Among the 76 patients, 30 eventually developed cervical metastasis. Preoperative plasma fibrinogen levels were determined and correlated with clinico-pathological findings by t-test or analysis of variance methods. Univariate and multivariate analyses were used to determine the association of preoperative plasma fibrinogen levels and disease-free survival. Elevated levels of plasma fibrinogen were positively related with growth type (P < 0.001), differentiation (P < 0.001), thickness (P < 0.001), and the infiltrative growth ratio (P = 0.032). Univariate analysis showed that growth type (P < 0.001), differentiation (P < 0.001), thickness (P < 0.001), and preoperative plasma fibrinogen levels (P < 0.001) were significantly correlated with disease-free survival. Multivariate analysis showed that the plasma fibrinogen level remained an independent factor for disease-free survival after partial glossectomy for OTSCC (P = 0.029). A high preoperative plasma fibrinogen level is an independent predictor of cervical metastasis after partial glossectomy for OTSCC. A conservative supraomohyoid neck dissection is appropriate in patients with stage I/II carcinoma of the tongue whose preoperative plasma fibrinogen is >300 mg/dl. © 2013 International Association of Oral and Maxillofacial Surgeons.

Zheng W.,Tianjin Stomatological Hospital | Wang S.,Third Central Hospital | Wang J.,Tianjin Stomatological Hospital | Jin F.,PLA Fourth Military Medical University
International Journal of Molecular Medicine | Year: 2015

The aim of the present study was to investigate the periodontitis-associated changes in the number, proliferation and differentiation potential of human periodontal ligament stem cells (PDLSCs). Cultures of human periodontal ligament cells (PDLCs) were established from healthy donors and donors with periodontitis. The numbers of stem cell were characterized using flow cytometry. PDLSCs were isolated from the PDLCs by immunomagnetic bead selection. Colony-forming abilities, osteogenic and adipogenic potential, gene expression of cementoblast phenotype, alkaline phosphatase activity and in vivo differentiation capacities were then evaluated. Periodontitis caused an increase in the proliferation of PDLSCs and a decrease in the commitment to the osteoblast lineage. This is reflected by changes in the expression of osteoblast markers. When transplanted into immunocompromised mice, PDLSCs from the healthy donors exhibited the capacity to produce cementum PDL-like structures, whereas, the inflammatory PDLSCs transplants predominantly formed connective tissues. In conclusion, the data from the present study suggest that periodontitis affects the proliferation and differentiation potential of human PDLSCs in vitro and in vivo.

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