ABSTRACT
BACKGROUND:Currently, the nickel-titanium file has no uniform international standards for clinical use, and several nickel-titanium systems have unique designs in terms of cross-sectional shape, taper change, composition number, central steel volume, and cutting edge angle, so there are some differences in cleanup capability, security, and cutting efficiency. ProTaper Next is developed based on the ProTaper Universal, and its composition number, blade cross-sectional shape, contact point with the root canal wal and the tip tapers are al improved. OBJECTIVE:To compare the shaping ability between ProTaper Next and ProTaper Universal Ni-Ti rotary endodontic instruments by preparing the simulated root canals. METHODS: Two groups of resin blocks were prepared by ProTaper Next and ProTaper Universal respectively. Preparation time and incidence of canal aberration and instruments failure were recorded. After preparation, the images taken before and after preparation were superimposed and analyzed by software Adobe Photoshop v7.0. We measured the amount of resin removed at the inner and outer canal wals. The centering ability was also assessed. RESULTS AND CONCLUSION:There was no difference in the incidence of canal aberration. ProTaper Next was faster than ProTaper Universal to prepare canals (P ProTaper Universal F2 removed more materials than ProTaper Next X2 at the inner canal wals (P < 0.05). ProTaper Next showed better centering ability than ProTaper Universal in most levels (P < 0.05). Two instruments showed good performance in preparation but both created some apical transportation. However, the ProTaper Next was better in maintaining the original form of curved canal with safety and higher efficiency.
ABSTRACT
<p><b>BACKGROUND</b>To elucidate the pattern and mechanism of cisplatin-induced apoptosis and its role in tumor chemotherapy.</p><p><b>METHODS</b>Apoptosis induced by cisplatin in human lung adenocarcinoma cell line A549 was detected by cell morphology, agarose gel electrophoresis, DNA-end-labeling and flow cytometry analysis techniques.</p><p><b>RESULTS</b>Cisplatin-induced apoptosis of A549 cells persisted and augmented gradually from 12 to 72 hours after treated with 3 mg/L cisplatin. All of A549 cells treated respectively with 1, 3, 5 and 7 mg/L cisplatin showed apoptosis. Apoptotic effects increased in a time-dependent pattern and a concentration-dependent pattern. A549 cells were blocked in G1 phase after treated with cisplatin.</p><p><b>CONCLUSIONS</b>Induction of cell apoptosis may be an important mechanism of anti-tumor efficacy of cisplatin.</p>
ABSTRACT
Objective To study the process of the root development of Codonopsis pilosula as well as theaccumulatinglocationsofthemainmedicinalcompositionandstoragenutritionintheroot. MethodsThe development process of the roots was studied by paraffin section methods. Storage nutrition was loca-lized by PAS reaction and Sudan Ⅲ reaction. The medicinal composition of C. pilosula, terpene and steroid were stained with mix reagent of 5% vanillin-acetic acid and perchloric acid. Results The development process of the root is shown as four stages: promeristem, primary meristem, primary structure, and secondary growth. Abundant laticifers exist in mature root and the prime laticifers could be found in phloem as early as the first vessel of primary xylem appears. Then, the laticifers exist in phloem at all time. Starch granule accumulated in mature root as reserved substance. Terpene and steroid accumulated in parenchyma and laticifer. Conclusion Parenchyma and laticifer in the roots of C. pilosula are the main parts of the roots to store medicinal composition and storage nutrition.