Objective Streptococcus sanguis is a possible candidate bacterium for the caries replacement therapy, which has no advantages in the acidic environment.The aim of the study was to construct acid-resistant strains of Streptococcus sanguis, determine its acid tolerance, and explore the mechanism of its antagonism against Sterptococcus mutans.Methods By gradually reducing the pH value of the medium, we constructed acid-resistant strains of Streptococcus sanguis, observed their growth and measured their acid tolerance according to their survival rate against lethal pH.We evaluated the competitive relationship between Streptococcus sanguis and Streptococcus mutans by plate experiment and detected the changes of related acid resistance genes by real-time quantitative PCR.Results The growth of Streptococcus sanguis and its acid-resistant strains were limited by the pH value, and that of Streptococcus sanguis was better in either acidic or normal environment.The lethal pH value of Streptococcus sanguis was 3.6, that of its acid-resistant strains was 2.3, and the survival rate of the acid-resistant strains was 66.59% in the pH 3.6 environment.In comparison, the lethal pH value of Streptococcus mutans was 2.5, that of its acid-resistant strains was 2.1, and the survival rate of the acid-resistant strains was 2.55% in the pH 2.5 environment.In the presence of chloramphenicol, the acid-resistant strains could not survive in the original lethal pH.In the sub-lethal pH environment, the expressions of the acid resistance-related genes Groel and Dnak in the acid-resistant strains were significantly up-regulated as compared with those in the original Streptococcus sanguis (P<0.05).Conclusion Streptococcus sanguis has an acid adaptability and can enhance acid resistance in the sub-lethal pH environment.Acid-resistant Streptococcus sanguis in the replacement therapy may provide some new ideas for the treatment of dental caries.

Objective Antimicrobial peptides are the focus of recent research in oral microbiology .This study aimed to eval-uate the activity of a novel antimicrobial peptide pm 11 against oral microorganisms and its action mechanisms . Methods We ana-lyzed the effect of pm11 on oral microorganisms and determined its antimicrobial activity in the saliva environment by measuring its min -imal inhibitory concentration (MIC), minimal bactericide concentration (MBC), and bactericidal kinetics.We observed its bacteri-cidal activity on the biofilms of streptococcus mutans by confocal laser scanning microscopy (CLSM) and the structural changes in the bacterial membrane by scanning electron microscopy (SEM). Results The antimicrobial activity of pm11 varied greatly against dif-ferent oral microorganisms , with its MIC values ranging from 2 μg/mL to 256 μg/mL and its MBC values from 2 μg/mL to >256μg/mL.The bactericidal kinetics showed a decreasing survival rate of bacteria with the lengthening of the intervention time .The inhib-itory-zone diameters exhibited no significant indifference between the water solution and the sterile saliva solution .CLSM revealed an increased number of dead bacteria in the pm 11-treated biofilms , while SEM manifested obvious changes in the shape of the bacteria membrane treated with pm11. Conclusion Our findings suggest that pm11 has a broad spectrum of antimicrobial activities on oral mi-croorganisms and a potential value of clinical application .

Liposomes, as one of the most successful nanotherapeutics, have a major impact on many biomedical areas. In this study, we performed laser scanning confocal microscope (LSCM) and immunohistochemistry (IHC) assays to investigate the intra-tumor transport and antitumor mechanism of GE11 peptide-conjugated active targeting liposomes (GE11-TLs) in SMMC7721 xenograft model. According to classification of individual cell types in high resolution images, biodistribution of macrophages, tumor cells, cells with high epidermal growth factor receptor (EGFR) expression and interstitial matrix in tumor microenvironment, in addition, their impacts on intra-tumor penetration of GE11-TLs were estimated. Type I collagen fibers and macrophage flooded in the whole SMMC7721 tumor xenografts. Tumor angiogenesis was of great heterogeneity from the periphery to the center region. However, the receptor-binding site barriers were supposed to be the leading cause of poor penetration of GE11-TLs. We anticipate these images can give a deep reconsideration for rational design of target nanoparticles for overcoming biological barriers to drug delivery.

Astrocytes are important nerve cells in the central nervous system （CNS）， which mainly play a key role in nutrition and support. Astrocytes and neurons undergo close energy coupling and substance coupling， which are closely related and interact with each other. In recent years， many studies have shown that the astrocyte-neuron coupling imbalance plays a central role in the occurrence and progression of Alzheimer's disease （AD） and serves as an important therapeutic target receiving increasing attention. According to traditional Chinese medicine （TCM） theory， the main pathogenesis of AD is kidney deficiency and marrow inadequacy， and in clinical medication， kidney-tonifying and marrow-filling TCM prescriptions are often employed with satisfactory results achieved. As reported， many kidney-tonifying and marrow-filling prescriptions exhibit regulatory and protective effects on the imbalance of astrocyte-neuron coupling， suggesting that the effect of kidney-tonifying and marrow-filling prescriptions in treating AD may have some internal relationship with its regulation of the imbalance of astrocyte-neuron coupling. This article reviewed the underlying internal relationship between the imbalance of astrocyte-neuron coupling and the pathogenesis of kidney deficiency and marrow inadequacy in AD and the research progress in the intervention mechanism of TCM for tonifying the kidney and filling the marrow.

OBJECTIVE：To evaluate the econo mics of pembrolizumab in the second-line treatment of advanced hepatocellular carcinoma in China. METHODS ：From the perspective of Chinese healthcare system ，a three-state PartSA model and Markov model were established ；the cost and utility for the second-line treatment of advanced hepatocellular carcinoma in China were compared between pembrolizumab and placebo. The circulation cycle of the model was 3 weeks and the study time limit was lifetime；one-way sensitivity analysis ，probability sensitivity analysis and scenario analysis were used to verify the robustness of the base-case analysis results. RESULTS ：PartSA results showed that the ICER for the second-line treatment of advanced hepato- cellular carcinoma with pembrolizumab was 1 266 846.18 yuan/QALY，which is far more than 1-3 times of China ’s per capita GDP in 2020. The results of one-way sensitivity analysis showed that the three parameters that had the greatest impact on ICER were the PFS status utility of the placebo group ，the PFS status utility of the pembrolizumab group ，and the cost of pembrolizumab. The results of probability sensitivity analysis verified the robustness of the base-case analysis. The scenario analysis showed that the treatment cost of pembrolizumab had dropped significantly when the charity donation of pembrolizumab was considered. Although it was still not economical ，ICER was close to 3 times of per capita GDP of China in 2020. When WTP threshold was 1 and 3 times of China ’s per capita GDP ，the economic prices of pabolizumab （100 mg）were 4 157.67 and 5 829.24 yuan，respectively. The results of Markov model were similar to those of PartSA model. CONCLUSIONS ：Under the WTP threshold of 1-3 times China ’s per capita GDP in 2020，pembrolizumab is not economical for second-line treatment of advanced hepatocellular carcinoma.

ObjectiveTo study the effects of Toddalia asiatica alcohol extract on autophagy and apoptosis of non-small cell lung cancer A549 cells， and to explore its possible mechanism. MethodA549 cells were cultured in vitro. Cell counting kit-8 （CCK-8） was used to detect the proliferation of A549 cells， and cell survival rate was calculated to screen the drug concentration. The apoptosis in each dose group and that after the use of 3-methyladenine （3-MA）， an autophagy inhibitor， were detected by flow cytometry combined with Annexin V-FITC/PI double staining. Western blot was used to detect the expression levels of apoptosis-related proteins such as B cell lymphocytoma-2（Bcl-2）， Bcl-2-associated X protein（Bax）， microtubule-associated protein 1 light chain 3 （LC3）， cleaved cysteinyl aspartate-specific protease-3 （cleaved Caspase-3）， activated poly （Adenosine diphosphate） ribonucleotide polymerase （cleaved PARP1）， PARP1， activated death activator （t-Bid）， Bid， and ubiquitin-binding protein p62 in each group and those after the use of 3-MA. ResultCompared with the conditions in the control group， the cell survival rate in 0.25 g·L^-1 group （P<0.05）， and 0.5， 1， 2， 4 g·L^-1 groups （P<0.01） was decreased after 24 h intervention. Additionally， the cell survival rate was reduced in a concentration-dependent manner at 48 h and it was less than 10% at 4 g·L^-1 （P<0.01）. Compared with the conditions in the control group， the total apoptosis rate in 0.5 g·L^-1 group was increased （P<0.05）， and the apoptosis rate in 1 and 2 g·L^-1 groups was also increased （P<0.01）. Compared with the 2 g·L^-1 group and 3-MA group， the 3-MA combined with T. asiatica alcohol extract had significantly decreased apoptosis rate （P<0.01）. Compared with the conditions in the control group， elevated expression of pro-apoptotic proteins cleaved PARP1， Bax and t-Bid in 1 and 2 g·L^-1 groups （P<0.05， P<0.01）， and reduced expression of Bid in the 2 g·L^-1 group （P<0.01） were found. Compared with the conditions in the control group， the expression of anti-apoptotic protein Bcl-2 （P<0.05， P<0.01） and the level of p62 （P<0.01） were down-regulated in 0.5， 1， 2 g·L^-1 groups， while the level of LC3 Ⅱ protein was up-regulated （P<0.01）， with certain concentration dependence. ConclusionT. asiatica alcohol extract could significantly inhibit the proliferation of A549 cells， which might be related to promoting autophagy and inducing apoptosis.