The removal of three kinds of occlusal veneers by Er: Yag laser / 华西口腔医学杂志

OBJECTIVES@#This study aimed to remove occlusal veneers of varied thicknesses and compositions by Er:Yag laser in vitro and analyze the interfacial microstructure between veneers and tooth that irradiated by laser, by which experimental evidence could be provided to support the non-invasive removal of occlusal veneerby laser.@*METHODS@#Fresh mandibular premolars extracted for orthodontic requirements were collected for tooth preparation. Three kinds of ceramic materials (Vita Suprinity, Vita Mark Ⅱ, and Upcera Hyramic) were selected to fabricate occlusal veneer with different thicknesses (1.0, 1.5, and 2.0 mm). One week later, Er:Yag laser (2.5 W and 3.5 W) was used to irradiate and remove the occlusal veneer and recorded the timespan. After the removal operation, the micro-morphologies of samples were examined by scanning electron microscope.@*RESULTS@#Upcera Hyramic veneer failed to be removed (>20 min); the operation span at 2.5 W, Vita Suprinity (96.0 s±16.0 s) was longer than Vita MarkⅡ(84.5 s±19.5 s) in the 1.0 mm group (P<0.05), and Vita Suprinity (246.5 s±13.5 s) was longer than Vita MarkⅡ(170.0 s±14.0 s) in the 1.5 mm group (P<0.05). At 3.5 W, Vita Suprinity (381.0 s±24.0 s) was longer than Vita MarkⅡ(341.5 s±26.5 s) in the 2.0 mm group.@*CONCLUSIONS@#Increasing laser power could shorten the operation span and facilitate the removal of occlusal veneers with the same thickness and composition. The occlusal veneer was sustained when insufficient laser power was applied. With the same laser power and ceramic thickness, laser penetration could interfere with the integral of the ceramic structure when the laser interacted with the bonding layer. With the same ceramic composition and laser power, the operation span and laser power increased with the thickness of the occlusal veneer. However, the laser was incapable of removing occlusal resin veneer directly.

Comparing rice production systems in China: Economic output and carbon footprint.

In recent years, many rotational and integrated rice production systems coupled with several greenhouse gas (GHG) emissions mitigation practices have been developed and adopted for demand of low carbon production. However, there have been only few studies about comparisons on the balance between high production and mitigation of GHG emissions in different rice production systems. We therefore aimed to evaluate economic output and carbon footprint of different rice production systems, based on several long-term experiments conducted by our lab. CH4 and N2O emission were measured by the same static chamber/gas chromatogram measurement procedure in different rice production systems, including rice-fallow, rice-rapeseed, rice-wheat, double rice, and integrated rice-crayfish production system. Then, we applied the DeNitrification DeComposition model to simulate CH4 and N2O emission over different years under the same condition for comparison. Carbon footprint was calculated following the process-based life cycle assessment (PLCA) methodology. The economic benefit of rice production systems was assessed by cost-benefit analysis. According to the analysis, the double-rice production system exhibited the highest intensity of carbon footprint (ICF = 4.14 kg CO2-eq yuan-1), rain-fed treatment in the rice-rapeseed system had the lowest (ICF = 0.68 kg CO2-eq yuan-1). The intensity of carbon footprint in different treatments in the integrated rice-crayfish production system was around 0.8 kg CO2-eq yuan-1. Overall, the results of this case study suggest: (1) the proposed practices in different rice production systems are no straw returning (rice-fallow), no-tillage without straw returning (rice-wheat), rain-fed farming (rice-rapeseed), no insect and no inoculation (double rice), and feeding with straw returning (rice-crayfish); (2) rotational and integrated systems can achieve high net output with low carbon emission; (3) reducing the amount of nitrogenous fertilizer application is the most important and effective GHG mitigation practice for rotational systems.

COE inhibits vasculogenic mimicry in hepatocellular carcinoma via suppressing Notch1 signaling.

ETHNOPHARMACOLOGICAL RELEVANCE: Vasculogenic mimicry (VM) has been suggested to be present in various malignant tumors and associated with tumor nutrition supply and metastasis, leading to poor prognosis of patients. Notch1 has been demonstrated to contribute to VM formation in hepathocellular carcinoma (HCC). Celastrus orbiculatus extract (COE), a mixture of 11 terpenoids isolated from the Chinese Herb Celastrus orbiculatus Vine, has been suggested to be effective in cancer treatment. AIM OF THE STUDY: In the current study, experiments were carried out to examine the effect of COE on VM formation and HCC tumor growth both in vitro and in vivo. MATERIALS AND METHODS: CCK-8 assay and Nikon live-work station were used to observe the viability of malignant cells treated with COE. Cell invasion was examined using Transwell. Matrigel was used to establish a 3-D culture condition for VM formation. Changes of mRNA and protein expression were examined by RT-PCR and Western Blot respectively. Tumor growth in vivo was monitored using in vivo fluorescence imaging device. PAS-CD34 dual staining and electron microscopy were used to observe VM formation. Immunohistochemical staining (IHC) was used to examine Notch1 and Hes1 expression in tumor tissues. RESULTS: Results showed that COE can inhibit HCC cells proliferation and invasion in a concentration-dependent manner. VM formation induced by TGF-ß1 was blocked by COE. In mouse xenograft model, COE inhibited tumor growth and VM formation. Both in vitro and in vivo studies showed that COE can downregulate expression of Notch1 and Hes1. CONCLUSION: The current results indicate that COE can inhibit VM formation and HCC tumor growth by downregulating Notch1 signaling. This study demonstrates that COE is superior to other anti-angiogenesis agents and can be considered as a promising candidate in HCC treatment.

Notch1 promotes vasculogenic mimicry in hepatocellular carcinoma by inducing EMT signaling.

Hypervascularity is one of the main characteristics of hepatocellular carcinoma (HCC). However, the mechanisms of angiogenesis in HCC remain controversial. In this study, we investigate the role of Notch1 in angiogenesis of HCC. We found that Notch1 expression was correlated with formation of vasculogenic mimicry (VM) and expression of biomarkers of epithelial-to-mesenchymal transition (EMT) in the tumor specimens. Two HCC cell lines, HepG2 and MHCC97-H, with low and high Notch1 expression, respectively, were used to study the mechanism of VM formation both in vitro and in vivo. It was found that MHCC97-H cells, but not HepG2 cells form VM when they grow on matrigel in vitro. HepG2 cells gained the power of forming VM when they were overexpressed with Notch1, while knockdown Notch1 expression in MHCC97-H cells led to the loss of VM forming ability of the cells. Similar results were found in in vivo study. High expression of Notch1 in HepG2 promoted xenograft growth in nude mice, with abundant VM formation in the tumor samples. Moreover, we observed Notch1 was associated with the EMT and malignant behavior of hepatocellular carcinoma by analyzing clinical specimens, models for in vitro and in vivo experiments. HepG2 presented EMT phenomenon when induced by TGF-ß1, accompanied by Notch1 activation while MHCC97-H with knockdown of Notch1 lost the responsiveness to TGF-ß1 induction. Our results suggest that Notch1 promotes HCC progression through activating EMT pathway and forming VM. Our results will guide targeting Notch1 in new drug development.

Vasculogenic mimicry in hepatocellular carcinoma contributes to portal vein invasion.

Portal vein invasion (PVI) is common in hepatocellular carcinoma (HCC) and largely contributes to tumor recurrence after radical tumor resection or liver transplantation. Vasculogenic mimicry (VM) was an independent vascular system lined with tumor cells and associated with poor prognosis of HCC. The present study was conducted to evaluate the relationship between VM and portal vein invasion. A total of 44 HCC cases receiving anatomic liver resection were included in the study and were divided into groups with and without PVI. The prevalence of VM in each group was examined by CD34-PAS dual staining. The regulatory molecules of VM formation such as Notch1, Vimentin and matrix metalloproteinases (MMPs) were investigated by immunohistochemical staining. Analysis was performed to explore the association of PVI, VM and the VM regulatory molecules. PVI was found in 40.91% (18/44) cases and VM was found in 38.64% (17/44) cases in total samples. The incidence of VM was 72.22% (13/18) in PVI group while it was 15.38% (4/26) in non-PVI group (P<0.001), VM formation was positively correlated with PVI (r=0.574, P<0.001). The VM forming regulatory molecules such as Notch1, Vimentin, MMP-2 and MMP-9 were found to be correlated with PVI in HCC patients. Taken together, our results suggested that VM formation, alone with its regulatory molecules, is the promoting factor of PVI in hepatocellular carcinoma.

Agrobacterium-mediated transformation of Cymbidium sinensis / 生物工程学报

Genetic transformation is an effective method to improve breeding objective traits of orchids. However, there is little information about genetic transformation of Cymbidium sinensis. Rhizomes from shoot-tip culture of C. sinensis cv. 'Qijianbaimo' were used to establish a practical transformation protocol of C. sinensis. Pre-culture time, concentration and treating methods of acetosyringone, concentration of infection bacteria fluid (OD600), infection time, and co-culture time had significant effects on β-glucuronidase (GUS) transient expression rate of C. sinensis cv. 'Qijianbaimo' rhizome. The GUS transient expression rate of rhizome was the highest (11.67%) when rhizomes pre-cultured for 39 d were soaked in bacterium suspension (OD600 = 0.9) supplemented with 200 μmol/L acetosyringone for 35 min, followed by culturing on co-culture medium supplemented with 200 μmol/L acetosyringone for 7 d. Under this transformation conditions, 3 transgenic plantlets, confirmed by GUS histochemical assay and PCR, were obtained from 400 regenerated plantlets, and the genetic transformation rate was 0.75%. This proved that it was feasible to create new cultivars by the use of Agrobacterium-mediated genetic transformation in C. sinense.

Expression of Ki67 and P53 proteins in gingival tissue after wearing four kinds of temporary crowns / 实用口腔医学杂志

Objective:To study the expression of Ki67 and P53 proteins in gingival tissue after wearing four kinds of temporary crowns.Methods:The experiment animal model was established by temporary prosthesis on dogs' teeth using chemical-curing resin,thermal-curing resin,DMG-TEMP crown material and SWIFT composite resin respectively.The immunohistochemistry Envision method was used to measure the expression of Ki67 and P53 proteins in gingival tissue before tooth preparation,after tooth preparation,1-and 2-week,1 month after wearing the crowns.The teeth without any treatment were surved as control.HE stained gingival tissue slices were observed under microscope.Results:The expression of Ki67 and P53 proteins in gingival tissue increased 1 week after wearing the chemical-curing resin crowns or thermal-curing resin crowns(P0.05).No pathological change was observed in all the samples.Conclusion:Chemical-curing resin crowns and thermal-curing resin crowns may increase the expression of Ki67 and P53 proteins in gingival tissue,but DMG-TEMP crowns and SWIFT resin crowns do not.None of the four kinds of temporary crowns may cause abnormal proliferation of gingival epithelia.