[Characteristics of caries-related oral microorganisms in early childhood caries].

PURPOSE: To study the structural characteristics of oral microorganisms in children with caries by 16S rRNA high-throughput sequencing technology. METHODS: Thirty healthy children aged 3-5 years were enrolled as subjects. According to the index of dmfs, they were divided into caries-free (CF) group (15) and early childhood caries (ECC) group(15). To compare the differences in bacterial community structure, samples of saliva and dental plaque were collected, and high-throughput sequencing was conducted using the Illumina Miseq sequencing platform. Bioinformatics analysis was used to analyze the difference of microbial community structure and diversity with SPSS 23.0 software package. RESULTS: Microbial diversity in ECC group was significantly lower than CF group. At phylum level, Actinobateria was more abundant in saliva samples of ECC group, while Firmicutes was more abundant in plaque samples of CF group. At genus level, the abundance of Lautropia of CF group was higher in saliva samples while Cardiobacterium, Gemella and Granulicatella were abundant in plaque samples. The abundance of Rothia of ECC group was higher in saliva samples and Corynebacterium was abundant of ECC group in plaque samples. CONCLUSIONS: There are significant differences in the species and composition of microbial community in saliva and plaque of children with or without caries. Specific microorganisms are related to the occurrence of ECC, and screening specific microorganisms is helpful for early prediction and prevention of ECC.

[Correlation of K-ras Gene Mutations with the Protein Expressions of TAK1 and MAP4K2 in Colorectal Cancer].

OBJECTIVE: To analyze the correlation of K-ras gene mutations with the protein expressions of transforming growth factor-ß activating kinase 1 (TAK1) protein and mitogen-activated protein kinase kinase kinase kinase 2 (MAP4K2) protein in colorectal cancer. METHODS: K-ras gene mutations were detected by DNA sequencing analysis, and the expressions of TAK1 protein and MAP4K2 protein were detected by immunohistochemical method in 76 cases of colorectal cancer tissues. RESULTS: In 76 cases of colorectal cancer tissues, the mutation rate of K-ras gene was 32.89% (25 cases), and K-ras gene mutations were correlated with the degrees of cell differentiation ( P<0.05). The positive rates of TAK1 protein and MAP4K2 protein were 48.68% and 46.05%, respectively. The protein expressions of TAK1 and MAP4K2 were positively correlated with the degrees of cell differentiation and lymph node metastases, respectively ( P<0.05). There was no correlation between K-ras gene mutation and either TAK1 protein or MAP4K2 protein expression ( P>0.05). In 25 cases of colorectal cancer with K-ras mutation, the expression of TAK1 protein was positively correlated with the expression of MAP4K2 protein ( P<0.05). CONCLUSION: K-ras gene mutation, TAK1 and MAP4K2 protein expressions were related to the degree of differentiation of colorectal cancer, but not to the depth of invasion. In colorectal cancer with K-ras gene mutation, the expression of TAK1 protein was positively correlated with the expression of MAP4K2 protein.