ABSTRACT
Bacteria-mediated anti-tumor therapy has received widespread attention due to its natural tumor-targeting ability and specific immune-activation characteristics. It has made significant progress in breaking the limitations of monotherapy and effectively eradicating tumors, especially when combined with traditional therapy, such as radiotherapy. According to their different biological characteristics, bacteria and their derivatives can not only improve the sensitivity of tumor radiotherapy but also protect normal tissues. Moreover, genetically engineered bacteria and bacteria-based biomaterials have further expanded the scope of their applications in radiotherapy. In this review, we have summarized relevant researches on the application of bacteria and its derivatives in radiotherapy in recent years, expounding that the bacteria, bacterial derivatives and bacteria-based biomaterials can not only directly enhance radiotherapy but also improve the anti-tumor effect by improving the tumor microenvironment (TME) and immune effects. Furthermore, some probiotics can also protect normal tissues and organs such as intestines from radiation via anti-inflammatory, anti-oxidation and apoptosis inhibition. In conclusion, the prospect of bacteria in radiotherapy will be very extensive, but its biological safety and mechanism need to be further evaluated and studied.
ABSTRACT
【Objective】 To explore the effect of low levels of calcium on the biological characteristics of ameloblasts. 【Methods】 Rat primary ameloblasts were cultured in standard DMEM medium. After five days they were identified by RT-PCR and immunohistochemistry. Then 0, 0.6 and 1.2 mmoL/L Ca2+ and 100 mL/L fetal bovine serum were added into DMEM medium without calcium. After 48 hours, the cell morphology was observed by inverted microscope. The proliferation and apoptosis of cells were separately examined by MTT and AnnexinV-PI. Real-time quantitative PCR was used to detect the expression levels of amelogenin and KLK4 mRNA. 【Results】 After Five days in standard DMEM medium, the cells were shaped like the paving pattern. RT-PCR showed that both amelogenin and KLK4 were expressed in the cells. Immunohistochemical staining showed that most cells had positive staining for amelogenin. After 48 hours of calcium intervention, some cells in 1.2 mmoL/L Ca2+ group had higher nuclear density and poor light transmittance, and more high columnar cells could be observed in 1.2 mmoL/L Ca2+ group than those in 0 and 0.6 mmoL/L Ca2+ groups. With the decrease in calcium concentration in the medium, MTT showed that the proliferation activity of ameloblasts reduced (P<0.01). Annexin V-PI showed that the percentage of apoptotic cells decreased, and there was a significant difference between 1.2 mmoL/L and 0 mmoL/L Ca2+ groups (P<0.05). Real time-PCR showed that the expressions of amelogenin and KLK4 mRNA reduced (P<0.01). 【Conclusion】 Low-level calcium may inhibit the differentiation of ameloblasts, thereby affecting the formation of enamel mineralization.
ABSTRACT
Objective:Understand the status of brushing teeth behavior of preschoolers in Shaanxi Province, to provide basis for oral health of preschoolers.Methods:By adopting the methods of multi-stage, stratified, geometric and cluster sampling, 1 370 kindergarten students at the age of 3-5 in Shaanxi Province were sampled as respondents to implement oral health questionnaire.Results:49.2%(674/1 370) children brushed their teeth every day, including only 14.8%(203/1 370) children brushing their teeth twice or above. Therefore, the difference of the brushing frequency (≥ 1 time/day) between urban and rural areas had obvious statistical significance ( χ2 value was 47.588, P<0.01). 98.7%(741/750) children used toothpaste, including only 6.9% (51/741) using toothpaste with fluoride. Therefore, the use of toothpaste between urban and rural areas has no statistical significance. Only 0.5% (4/751) children started to brush their teeth when their first deciduous tooth erupted. Therefore, the age for children starting to brush their teeth between urban and rural areas had obvious statistical significance ( χ2 value was 24.217, P<0.01). 65.2% (490/751)parents never helped their children to brush teeth, parents in rural areas even reached to 72.8% (227/312). Therefore, the brushing frequency for parents helping their children to brush teeth between urban and rural areas had statistical difference ( χ2 value was 16.192, P<0.01). Conclusions:The status of brushing teeth behavior of preschoolers in Shaanxi Province is lower than the national level, and the level in rural areas is obviously lower that in urban areas. The education and cultivation on brushing teeth behavior should be further strengthened in the future propaganda and education, especially, the power of propaganda on children and parents in rural areas should be strengthened.
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砄bjective:To investigate the effects of salivary statherin on adherence of two kinds of main cariogenic bacteria. Methods: Human whole salivary statherin was separated and purified by high performance hydrophobic interaction chromatography (HPHIC) and was further identified by SDS PAGE electrophoresis and amino acid analysis.Then the adherence of Streptococcus mutans ( S.mutans serotype c,7H) and Sreptococcus sanguis (S.sanguis ,ATCC 10557)to hydroxyapatite (HA), which was covered with purified statherin or whole saliva (positive control) or PBS buffer (negative control) as experimental pellicles respectively,was studied by bacteria counting.Results:①More S.sanguis adhered to the experimental pellicles than S.mutans ( P