[Cone beam computed tomography evaluation of bifid mandibular canals in the adult population in Sichuan Province].

OBJECTIVE: To investigate the incidence of bifid mandibular canals (BMC), and analyze the types, courses, and anatomic features of the variant canals in the adult population in Sichuan Province. METHODS: Five hundred patients (1 000 hemimandibles) underwent cone beam computed tomography (CBCT) were included in this study. The incidence, bifurcate types and courses of the BMC were evaluated. RESULTS: The incidence of BMC was 13.8% (69/500) in the study, 9.2% in terms of total hemimandibles. The most frequently type was retromolar canals, followed by the dental and buccolingual type, meanwhile the lowest was the forward type. The mean diameter of the accessory canals was 0.90 mm and the mean length was 9.39 mm. CONCLUSIONS: CBCT used in this study has shown that the incidence of BMC assessed by CBCT was significantly higher than panoramic radiography. Furthermore, CBCT can depict the position, course, size and the branches of the mandibular canals.
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Functions of oligochitosan induced protein kinase in tobacco mosaic virus resistance and pathogenesis related proteins in tobacco.

Oligochitosan (OC) can regulate plant defense responses in many aspects, but the basic signal transduction pathway is still unclear. In this study, we used transgenic (TG) tobacco (Nicotiana Tabacum var. Samsun NN) as plant material whose oligochitosan induced protein kinase (OIPK) gene was inhibited by antisense transformation, to study the role of OIPK in tobacco defense reactions. The results showed that OIPK could increase tobacco resistance against tobacco mosaic virus (TMV), in that wild-type (WT) tobacco showed longer lesion appearance time, higher lesion inhibition ratio, smaller average final lesion diameter and lower average final lesion area percent to whole leaf area. It led us to analyze some pathogenesis related (PR) enzymes' activities and mRNA level, which played roles in tobacco resistance against TMV. We found that phenylalanine ammonia-lyase (PAL) and peroxidase (POD) activities were positively related to OIPK, but not polyphenol oxidase (PPO). It was also demonstrated that OIPK mRNA could be induced by OC, wound and TMV infection. In addition, OIPK could up-regulated three PR genes, PAL, chitinase (CHI) and beta-1, 3-glucanase (GLU) mRNA level to different extent. Taken together, these results implied that OIPK could function in tobacco resistance against both biotic and abiotic stress, possibly via various PR proteins.