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With the improvement of living standards and oral health awareness in people and with the development of the techniques in orthodontic therapy,the number of adult patients in orthodontics is gradually increasing. Due to adults' social occupations,psychological factors,complicated intraoral status,these factors make adult patients differences from adolescents. In this paper,the problems related with adult orthodontic treatment were reviewed.

Wnt-β-catenin signaling participates in the epithelial-mesenchymal transition (EMT) in a variety of cancers; however, its involvement in hepatocellular carcinoma (HCC) and downstream molecular events is largely undefined. HNF4α is the most prominent and specific factor maintaining the differentiation of hepatic lineage cells and a potential EMT regulator in HCC cells. However, the molecular mechanisms by which HNF4α maintains the differentiated liver epithelium and inhibits EMT have not been completely defined. In this study, we systematically explored the relationship between Wnt-β-catenin signaling and HNF4α in the EMT process of HCC cells. Our results indicated that HNF4α expression was negatively regulated during Wnt-β-catenin signaling-induced EMT through Snail and Slug in HCC cells. In contrast, HNF4α was found to directly associate with TCF4 to compete with β-catenin but facilitate transcription co-repressor activities, thus inhibiting expression of EMT-related Wnt-β-catenin targets. Moreover, HNF4α may control the switch between the transcriptional and adhesion functions of β-catenin. Overexpression of HNF4α was found to completely compromise the Wnt-β-catenin-signaling-induced EMT phenotype. Finally, we determined the regulation pattern between Wnt-β-catenin signaling and HNF4α in rat tumor models. Our studies have identified a double-negative feedback mechanism controlling Wnt-β-catenin signaling and HNF4α expression in vitro and in vivo, which sheds new light on the regulation of EMT in HCC. The modulation of these molecular processes may be a method of inhibiting HCC invasion by blocking Wnt-β-catenin signaling or restoring HNF4α expression to prevent EMT.

The genetic diversity of picoeukaryotic phytoplankton in the 30 lakes along the middle-lower reaches of the Yangtze River was studied using flow cytometry combined with terminal restriction fragment length polymorphism (T-RFLP). The objectives of this study were to confirm the variance in the genetic diversity of picoeukaryotic phytoplankton among the lakes and to reveal its main affecting factors. Though the lakes investigated tended to or already were eutrophic, T-RFLP profiles of 18S rRNA gene fragments from picoeukaryotic phytoplankton showed high diversity. There were altogether 197 T-RFs detected from the lakes that we investigated, with 89 of them obtained in less than 3 lakes. Cluster analysis indicated their similarity was lower than 80%. Shannon-wiener diversity index showed that mesotrophic lakes contained more diverse picoeukaryotic phytoplankton community than eutrophic lakes. The canonical correspondence analysis revealed that the concentration of the total nitrogen had the most important impact on the picoeukaryotic phytoplankton communities (P =0. 006). The results showed that the genetic diversity of picoeukaryotic phytoplankton in the lakes were of great environmental heterogeneity and closely related to the trophic status. Two CCA axes can only explain 10.0% of the total variance in picoeukaryotic phytoplankton composition, suggesting that the evolution of picoeukaryotic phytoplankton was probably connected to the top-down manipulation as well.

Fifty strains of bacteria were isolated from six isolates of the nematode Bursaphelenchus mucronatus (Bm) from China and Russia and identified using the BioMerieux Vitek 32 system. In bioassay, 3 bacterial strains showed the high levels of phytotoxin production while 19, 16, and 12 strains showed moderately, low and no phytotoxin production, respectively. Inoculation of 2-month-old Pinus thunbergii seedling with each of the six Bm isolates showed that the mean number of days from inoculation to death of 80% of the seedlings was significantly related to the ratio of the total number of bacterial strains for a nematode isolate to the number of pathogenic bacterial strains of the nematode isolate. The results of inoculation of 3-year-old P. thunbergii seedlings showed that inoculation with either axenic Bm (ABm) or axenic B. xylophilus (ABx) and the pathogenic bacterial strain together were essential for inducing pine wilt. These findings demonstrate that wilt symptoms caused by Bm conform to our earlier hypothesis (Zhao et al., 2003) that pine wilt disease, induced by certain Bx or Bm isolates, is caused by a complex of both the nematodes and their associated pathogenic bacteria. The results also account for the variation in pathogenicity of Bm populations from different parts of the world.