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ABSTRACT: Hepatocyte growth factor (HGF) is a multifunctional cytokine that is able to stimulate multiple intracellular signaling pathways to induce a remarkable variety of biological activities in a wide spectrum of cell types. The functions of HGF in modulating diverse biological responses in mesenchymal stem cells have been reported, and our previous study also demonstrated that HGF exerts promoting functions on murine dental papilla cells. However, the potential mechanisms involved are not yet clearly understood. This study investigated the signaling pathway used by HGF in human dental papilla cells (hDPCs) to identify the role of mitogen-activated protein kinase (MAPK) pathways in inducing cell proliferation, differentiation, and migration.
The activation of P38 kinase and Jun N-terminal kinase (JNK) was analyzed by using specific antibodies against phospho-P38 and phospho-JNK. Proliferation of hDPCS was measured using the WST-8 assay with Cell Counting Kit-8, cell differentiation was determined by using alkaline phosphatase activity and mineralization assays, and migration was investigated by in vitro wound healing and transwell migration assays. Immunofluorescence staining was used to visualize fibrous actin (F-actin).
HGF activated JNK and P38 MAPK pathways in hDPCs. Blockage of JNK or P38 pathway in hDPCs significantly reduced cell proliferation, alkaline phosphatase activities, as well as mineral nodule formation induced by HGF. The JNK and P38 inhibitors also influenced F-actin remodeling stimulated by HGF and thus contributed to HGF-induced hDPCs migration.
Data from this study indicated that JNK and P38 MAPK pathways are required in HGF-induced biological responses in hDPCs.
Journal of endodontics 09/2012; 38(9):1207-13. · 2.95 Impact Factor
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ABSTRACT: Slit is a secreted protein known to function through the Roundabout (Robo) receptor. Slit has recently been shown to be an endogenously available inhibitor of leukocyte chemotaxis and as a chemoattractant to recruit vascular endothelial cells to sites for angiogenesis both in vivo and in vitro. The initiation and progression of periodontal diseases, is the result of complex interactions between the colonizing bacteria in the periodontal pockets and host immune and inflammatory responses. Antibiotics such as tetracyclines are commonly used in the management of periodontal infections and yet, have shown modest success in reducing neutrophil-mediated injury. Angiogenesis is important for the maintenance of homeostatus of periodontal tissues. However, few studies have been reported about angiogenesis targeted treatment for periodontitis. Based on its angiogenesis promoting effect and leukocyte chemotaxis inhibition effect, we hypothesize that Slit can be an effective immunotherapeutic agent in the treatment of periodontitis.
Medical Hypotheses 05/2012; 79(2):186-8. · 1.39 Impact Factor
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ABSTRACT: A new capillary zone electrophoresis method with laser-induced fluorescence detection is presented for the determination of
noradrenaline (NA) and dopamine (DA). The fluorescent reagent, 5-(4,6-dichloro-s-triazin-2-ylamino) fluorescein, which readily
reacts with amine group under mild conditions, was initially used to label the two compounds. Under optimized separation and
labeling conditions, linear relationship between peak area and analyte concentration was obtained with high sensitivity (nM
level). The applicability of the method for complex sample analysis was validated by determining the two compounds in a human
serum and an herb, Portulaca oleracea L with recoveries ranging from 89% to 102%.
Microchimica Acta 04/2012; 166(3):289-294. · 3.03 Impact Factor
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ABSTRACT: The choice of single- versus multiple-visit root canal treatment for infected teeth is in dispute. The purpose of this systematic review was to compare the healing rate and post-obturation pain of single- versus multiple-visit root canal treatment for teeth with infected root canals.
An exhaustive literature search combined with specified inclusion criteria was performed to identify randomized or quasi-randomized controlled trials (RCTs or quasi-RCTs), comparing root canal treatment in single and multiple appointments (2 or more visits) in patients with infected root canals.
Ten RCTs were identified and included in this review. Of these, 6 compared the healing rate and 5 compared the prevalence of post-obturation pain in single- and multiple-visit root canal treatment on teeth with infected root canals. No significant difference was observed in the healing rate between single- versus multiple-visit root canal treatment, as well as the incidence of medium-term post-obturation pain. As to the short-term follow up, the prevalence of post-obturation pain was significantly lower in single-visit than in multiple-visit group.
On the basis of current studies, the healing rate of single- and multiple-visit root canal treatment is similar for infected teeth. Patients experience less frequency of short-term post-obturation pain after single-visit than those having multiple-visit root canal treatment.
Journal of endodontics 02/2011; 37(2):125-32. · 2.95 Impact Factor
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ABSTRACT: Diabetes mellitus is a common health problem with serious consequences. Researches suggested the relationship between diabetes and endodontic problems. Vitamin D has important biologic effects on glucose homeostasis, insulin release and response, and is considered to play a role in the pathogenesis of diabetes. Vitamin D can also influence the alveolar bone formation and inflammatory reactions in periradicular tissues. The hypothesis we proposed is that vitamin D may be beneficial to the prognosis of endodontic treatment for diabetic patients through two pathways.
Medical Hypotheses 12/2009; 74(4):673-5. · 1.39 Impact Factor
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ABSTRACT: Active oxygen species from the photocatalytic reaction in aqueous solution react with luminol to emit strong chemiluminescence (CL), and this can be inhibited by the UV decomposed-products of selenocystine (SeCys) or selenomethionine (SeMet). Based on this phenomenon, a novel hyphenated technique, HPLC-UV/nano-TiO(2)-CL, was established for the determination of SeCys and SeMet. The effects of pH, the UV irradiation time, the TiO(2) coated on the inner surface of the reaction tubing, and the Co(2+) catalyst concentration on the CL intensity and/or chromatographic resolution were systematically investigated. Under these optimized conditions, the inhibited CL intensity has a good linear relationship with the concentration of SeCys in the range of 0.04-10.6 microg mL(-1) or SeMet in the range of 0.05-12.4 microg mL(-1), with a limit of detection (S/N=3) of 6.4 microg L(-1) for SeCys or 12 microg L(-1) for SeMet. As an example, the method was preliminarily applied to the determination of the selenoamino acids in garlic and rabbit serum, with a recovery of 88-104%.
Journal of Chromatography B 07/2008; 870(2):216-21. · 2.89 Impact Factor
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ABSTRACT: In the present study, a simple and sensitive photo-induced chemiluminescence (CL) method for the quantitation of reducing sugars, including fructose, glucose, sucrose and lactose, was developed. This method was based on the on-line photocatalytic reaction of the reducing sugars, using a home-made photoreactor consisting of PTEF tube helically coiling around a high-pressure mercury UV lamp. Reducing sugars were detected by direct CL emission resulting from the reaction between the photoproducts and luminol. To maximize the signal intensity, the effects of irradiation time, flow rate, luminol concentration, buffer pH and concentration were tested. Under optimum conditions, the linear dynamic ranges were all 0.36-18 mg/L and the relative standard deviations (RSDs) were 1.8-2.3%, with limits of detection (3sigma) of 0.06 mg/L for fructose, glucose, sucrose and lactose. Finally, interference effects from ascorbic acid, amino acids (alanine, glycine, serine, leucine and methionine) and some metal ions and anions were also investigated.
Luminescence 05/2008; 23(5):287-91. · 1.73 Impact Factor
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ABSTRACT: A new method based on ultrasonic slurry sampling atomic absorption spectrometry (AAS) was established for the determination
of trace mercury in geological samples by use of recently developed mercury cold vapor generation using formic acid under
ultraviolet (UV) irradiation. The generated mercury cold vapor was rapidly separated from the matrix and swept into a T-tube
for the measurement of atomic absorbance. Under the optimal experimental conditions, up to 1000-fold of Cu(II), Co(II), Ni(II),
Cr(VI), Mn(II), Fe(III), and Zn(II) caused no significant interference with the determination of 50 µg L−1 Hg. The limit of detection at sub-ppb level was obtained for mercury. The method was applied to the determination of mercury
in geological samples with satisfactory results.
Microchimica Acta 12/2007; 160(1):191-195. · 3.03 Impact Factor
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ABSTRACT: A simple, sensitive and interference-free method was proposed for the determination of arsenic, based on the generation of volatile arsenic trichloride coupled with atomic fluorescence spectrometry. Thiourea, together with l-ascorbic acid, was used to reduce As(V) to As(III), and the chloride generation was based on the reaction between As(III) and hydrochloric acid. Under the optimized experimental conditions, the present procedure allows for the quantification of arsenic in the concentration range of 0.01-4.0 mg L(-1), with a limit of detection (3sigma) of 6.0 microg L(-1). The relative standard deviation (R.S.D.) is 4.0% for 0.1 mg L(-1) arsenic (n=7). Finally, the proposed method was successfully applied to the determination of arsenic in several certified reference samples (stainless steel, alloy steel, copper alloy and water sample) and real samples (brass material and spiked cobalt material), with analytical results well-agreed with those by ICP-MS.
Talanta 08/2007; 72(5):1728-32. · 3.79 Impact Factor
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Applied Spectroscopy Reviews 01/2007; 42(2):139-176. · 3.38 Impact Factor
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ABSTRACT: A novel on-line method based on the combination of UV photolysis and chemiluminescence detection was established and experimentally validated for the determination of chemical oxygen demand (COD). A quantitative amount of free radicals can be produced by analytes in the UV irradiation process. By utilizing the phenomenon that luminol can be oxidized by the free radicals to produce luminescence, COD was successfully determined indirectly. This new approach overcomes many problems associated with the conventional COD determination techniques such as long analysis time, tedious operations, consumption of expressive and toxic reagents, production of secondary toxic waste and poor reproducibility. The method was successfully applied to the determination of COD in synthetic samples, certified reference samples and real samples of river water and lake water. A limit of detection of 0.08 mg/L COD with a linear dynamic range of 0.2–20 mg/L was achieved under the optimum experimental conditions. The proposed method is a unique method that is environmentally friendly (without using any strong oxidizing reagent and any catalysts such as titanium dioxide), rapid (with only 5–10 min required for each sample), sensitive (with the lowest limit of detection for COD so far), simple (mainly with a photo-reactor and a chemiluminescence detector) and automated (using an intermittent flow system).
Microchemical Journal.
