Prominin-1 controls stem cell activation by orchestrating ciliary dynamics.

Proper temporal and spatial activation of stem cells relies on highly coordinated cell signaling. The primary cilium is the sensory organelle that is responsible for transmitting extracellular signals into a cell. Primary cilium size, architecture, and assembly-disassembly dynamics are under rigid cell cycle-dependent control. Using mouse incisor tooth epithelia as a model, we show that ciliary dynamics in stem cells require the proper functions of a cholesterol-binding membrane glycoprotein, Prominin-1 (Prom1/CD133), which controls sequential recruitment of ciliary membrane components, histone deacetylase, and transcription factors. Nuclear translocation of Prom1 and these molecules is particularly evident in transit amplifying cells, the immediate derivatives of stem cells. The absence of Prom1 impairs ciliary dynamics and abolishes the growth stimulation effects of sonic hedgehog (SHH) treatment, resulting in the disruption of stem cell quiescence maintenance and activation. We propose that Prom1 is a key regulator ensuring appropriate response of stem cells to extracellular signals, with important implications for development, regeneration, and diseases.

The relationship between periodontal disease and gastric cancer: A bidirectional Mendelian randomization study.

BACKGROUND: Previous observational studies have suggested a possible association between periodontal disease and gastric cancer (GC); however, a causal relationship has not yet been established. This study aimed to explore the causal relationship between the 2 through a 2-sample bidirectional Mendelian randomization (MR) study. METHODS: Genome-wide association studies (GWAS) summary statistics were obtained from publicly available GWAS and relevant databases. Two-sample bidirectional MR analysis was conducted to investigate the causal relationship between periodontal disease and GC using the inverse-variance weighted (IVW) method selected as the primary analytical approach. Cochran Q test, MR-PRESSO, MR-pleiotropy, and leave-one-out analyses were performed to assess heterogeneity, pleiotropy, and sensitivity. RESULTS: In European ancestry, IVW analysis revealed no causal relationship between periodontal disease and GC (OR = 1.873; 95% CI [4.788e-10, 7.323e + 09]; P = .956), or between loose teeth and GC (OR = 1.064; 95% CI [0.708, 1.598]; P = .765). In East Asian ancestry, there was no causal relationship between periodontitis and GC according to IVW (OR = 0.948; 95% CI [0.886, 1.015]; P = .126). Conversely, according to the results of the IVW analysis, there was no causal relationship between GC and periodontal disease, regardless of European or East Asian ancestry. Furthermore, there was no heterogeneity or pleiotropy in the causal relationships between these variables (all P > .05), suggesting a certain level of reliability in our results. CONCLUSION: Within the limitations of this MR study, we found no mutual causal relationship between periodontal disease and GC. This finding can prevent overtreatment by clinical physicians and alleviate the psychological burden on patients.

[Evaluation of the efficacy of two kinds of NiTi retreatment instruments for removing filling material during root canal retreatment].

PURPOSE: To compare the efficacy of Mtwo R and Reciproc with that of hand files in removing filling material during root canal retreatment. METHODS: The root canals of forty-five human extracted mandibular central incisors were cleaned and shaped to a size 40 and filled with gutta-percha and sealer using a lateral compaction technique. The teeth were divided into 3 groups. The filling material was removed with hand files, Mtwo R and Reciproc, respectively. The debris extruded out of the apical foramen was collected and weighted. The working time was recorded. Then the teeth were split longitudinally, observed under microscope, and evaluated. The data were statistically analyzed with SPSS 13.0 software package. RESULTS: There was no significant difference among 3 groups for debris extrusion (P>0.05). Removal of filling material with Mtwo R and Reciproc consumed less time (P<0.05). CONCLUTIONS: NiTi retreatment instruments can not remove all filling material during root canal retreatment, but can reduce working time.

[Analysis of Shanghai residents' cognition and approbation to dental practical clinic].

PURPOSE: To know about Shanghai residents' cognition and approbation to dental practical clinic and discuss the appropriate mode of clinical teaching. METHODS: 100 residents were chosen in five super-markets in five different districts randomly to fill in a questionnaire. RESULTS: 475 questionnaires were effective among 502 questionnaires and the efficiency was 94.62%; 10.32% informants knew the practical clinic, 56.84% informants would like to know it; 40.21% informants would like to choose the specialists, meanwhile 37.68% informants would choose the interns; 65.43% informants were satisfied with the dental interns. CONCLUSIONS: The cognition and approbation of residents to dental practical clinic should be enhanced, hospitals and schools should strengthen propaganda and improve teaching, in order to advancing the approbation based on upgrading the cognition.