Objective To construct markless gene deletion mutant at the clpP loci on the chromosome of Streptococcus mutans(S.mutans).Methods ASp resistance gene was amplified by PCR,to construct the Sp resistance cassette where the Sp resistance gene was flanked with two loxP site.After the clpP gene was cloned into the pGEM-T-Easy TA cloning vector,it was digested and linked with the Sp resistance cassette,yielding homologous recombination vector pIB △ clpP-Sp.The vector was linearized and used for the transformation of S.mutans UA159,with transformants selected on TPY plates containing Sp.The selected strain was transformed with the thermosensitive plasmid pCrePA to excise the Sp resistance gene.The pCre-PA was then easily eliminated at nonpermissive temperature,resulting in a markless mutant strain carrying a deletion at the clpP loci,which was verified by PCR and DNA sequencing.Results The result of the PCR analysis and DNA sequencing indicated that a part of the clpP gene was deleted.There was a loxP at this loci without the Sp resistance gene.Conclusion The markless clpP-deletion mutant of S.mutans was constructed successfully,which laid a foundation for further study of its biological function and its influence on the cariogenicity of S.mutans.

Microalgae is an easy-to-obtain natural biological material with many varieties and abundant natural reserves. Microalgae are rich in natural fluorescein, which can be used as a contrast agent for fluorescence imaging and photoacoustic imaging for medical imaging. With its active surface, microalgae can effectively adsorb functional molecules, metal elements, etc., and have good application prospects in the field of drug delivery. Microalgae can generate oxygen through photosynthesis to increase local oxygen concentration, reverse local hypoxia to enhance the efficacy of hypoxic tumors and promote wound healing. In addition, microalgae have good biocompatibility, and different administration methods have no obvious toxicity. This paper reviews the research progress on the biomedical application of microalgae in bioimaging, drug delivery, hypoxic tumor treatment, wound healing.
Drug Delivery Systems ; Humans ; Hypoxia ; Microalgae ; Oxygen ; Wound Healing

Objective: To investigate the relationship between core members' social capital and performance among HIV/AIDS-related community-based organizations (CBO). Methods: From July to December in 2015, a total of 327 core members from 212 HIV/AIDS-related CBO in 8 provinces were recruited based on the prevalence of HIV/AIDS (e.g., Yunnan, Hunan, and Sichuan are in high epidemic level; Anhui, Hubei, Shandong, and Jilin are in middle epidemic level; and Gansu is in low epidemic level) by multistage stratified cluster sampling and convenient sampling method. A questionnaire was administered in this study, including general demographic information, core members' social capital, individual performance and organizational performance. Multivariate logistic regression model was used to analyze the relationship between core members' social capital and performance among CBO. Results: Among the 327 individuals, the proportion of male was 201(61.47%). The proportion of core members from grassroots CBO was 66.97% (219/327). Core members from non-grassroots organizations were more likely to publish articles, the OR (95%CI) was 2.58 (1.30-5.14); Social network had a positive impact on the AIDS experts, the OR (95%CI) was 2.41(1.47-3.95); Core members from registered CBO were more likely to secure funding for the organization, the OR (95%CI) was 3.42 (1.65-7.10); Social network and the core members from high endemic areas were significantly correlated with the number of HIV/AIDS patients, the OR (95%CI) were 2.79 (1.27-6.14) and 1.99 (1.21-3.27). Conclusions We should use the core members' social network to establish relationship and communication with organizations and institutions, ultimately accelerating the growth of HIV/AIDS prevention and care.

Objective:To explore the safety of inactivating coronavirus disease 2019(covid-19)vaccine in liver transplantation(LT)recipients.Methods:Retrospective analysis was performed for clinical data of 151 LT recipients from March 2003 to October 2019.They had stable conditions and completed the course of covid-19 vaccine.Frequencies of pain at injection site, fatigue, headache and pruritus after vaccination were recorded.The safety profiles were compared between recipients with and without local and general adverse reactions after vaccination.At the same time, recipients completing two doses of covid-19 vaccines were grouped.According to vaccine companies, they were classified into Sinovac Biotech Ltd and Beijing Biological.Based upon more than or less than 60 years, they were grouped into <60 years and ≥60 years.The safety profiles of inactivating COVID-19 vaccine were compared in subgroups.Results:Among 151 eligible LT recipients, 98 of them were in group of age <60 years and 53 in group of age >60 years.The median period between vaccination and LT was 8.44(4.37, 12.39)years and the median concentration of tacrolimus 2.5(1.8, 3.9)ng/L.Eighty-three cases completed two doses of Sinovac Biotech Ltd(Sinovac Biotech Ltd group)and 40 cases Beijing Biological(Beijing Biological group); 14 cases had combined course of Sinovac Biotech Ltd and Beijing Biological, four recipients were vaccinated with inactivated vaccine from other companies and ten recipients did not know their inactivated vaccine' companies.After immunization, 24/151(15.9%)recipients had a local and general adverse reaction.The prevalence of pain at injection site, fatigue, headache and pruritus was 9.9%( n=15), 5.2%( n=8), 1.3%( n=2)and 0.7%( n=1)respectively.No significant differences existed in age( P=0.602), gender( P=0.752), period after LT( P=0.890), trough concentration of tacrolimus( P=0.377)or versions of covid-19 vaccine( P=0.582)between 24 cases with general adverse reaction and 127 without.Local and general reactions occurred in 16/83(19.3%)in Sinovac group and 5/40(12.5%)in Beijing Biological.There was no significant inter-group difference( P=0.769). There were 98 cases(64.9%)in <60 years group, 17 cases(17.3%)had local and general reaction, 53 cases(35.1%)in ≥60 years group and 7 cases(13.2%)had a local and systemic reaction.There was no significant inter-group difference( P=0.507). Conclusions:Covid-19 vaccine is safe for long-term survival LT recipients with normal liver function.Few participants present with mild fatigue and pain at injection site.

Objective To study the effect and mechanism of berberine (BBR) on the lung metastasis of mouse breast cancer via epithelial-mesenchymal transition (EMT). Methods CCK-8 and Transwell migration assays were utilized to investigate the proliferation and migration properties of breast cancer 4T1 cells after BBR treatment.Mouse 4T1-Luc cells were injected into mice under the fourth mammary fat pad, and the mice were then randomly divided into the control and BBR groups.The mice in the BBR group received daily intraperitoneal injections of BBR working solution and those in the control group were continuously intraperitoneally injected with the same volume of the solvent used to dissolve BBR powder.Tumor metastasis in the lungs of living mice was detected by using an in vivo imaging system.After 42 days of administration, lung metastasis was measured via microscopy and HE staining.Western blot analysis was used to examine the effects of BBR on the expression of EMT-related proteins (Vimentin and Snail) as well as the activation of the Akt and ERK signaling pathways. Results BBR significantly promoted 4T1 cell migration (P < 0.05).In vivo experiments showed that the number of lung metastases in the BBR group had significantly increased compared with that in control group (P < 0.05) as observed under microcopy and histological staining.Compared with the control group, BBR upregulated the expression levels of Vimentin and Snail as well as the phosphorylated levels of p-Akt and p-ERK (P < 0.05). Conclusion BBR may promote EMT and lung metastasis of breast cancer 4T1 cells by activating the expression of proteins in the p-Akt and p-ERK pathways.

Objective:To observe the recurrence condition of hepatitis B in different risk groups after liver transplantation in an attempt to provide useful information on whether to discontinue hepatitis B immunoglobulin (HBIG) in the future at an early stage.Methods:The patient population was divided into high, low-risk, and special groups [especially primary hepatocellular carcinoma (HCC)] according to the guidelines for the prevention and treatment of hepatitis B recurrence after liver transplantation. The recurrence condition and risk factors in this population were observed for hepatitis B. Measurement data were analyzed using a t-test and a rank-sum test. Count data were compared using a χ2 test between groups. Results:This study finally included 532 hepatitis B-related liver transplant cases. A total of 35 cases had HBV recurrence after liver transplantation, including 34 cases that were HBsAg positive, one case that was HBsAg negative, and 10 cases that were hepatitis B virus (HBV) DNA positive. The overall HBV recurrence rate was 6.6%. The recurrence rate of HBV was 9.2% and 4.8% in the high- and low-risk HBV DNA positive and negative groups before surgery ( P = 0.057). Among the 293 cases diagnosed with HCC before liver transplantation, 30 had hepatitis B recurrence after surgery, with a recurrence rate of 10.2%. The independent related factors for the recurrence of hepatitis B in patients with HCC after liver transplantation were HCC recurrence ( HR =181.92, 95% CI 15.99~2 069.96, P < 0.001), a high postoperative dose of mycophenolate mofetil dispersible tablets (MMF) ( HR =5.190, 95% CI 1.289~20.889, P = 0.020), and a high dosage of HBIG ( HR = 1.012, 95% CI 1.001~1.023, P = 0.035). Among the 239 cases who were non-HCC before liver transplantation, five cases (recurrence rate of 2.1%) arouse postoperative hepatitis B recurrence. Lamivudine was used in all cases, combined with on-demand HBIG prophylaxis after surgery. There was no hepatitis B recurrence in non-HCC patients who treated with entecavir combined with HBIG after surgery. Conclusion:High-barrier-to-resistance nucleotide analogues combined with long-term HBIG have a good effect on preventing the recurrence of hepatitis B after liver transplantation. The discontinuation of HBIG may be considered at an early stage after administration of a high-barrier-to-resistance nucleotide analogue in low-risk patients. Domestically, the HBV infection rate is high, so further research is still required to explore the timing of HBIG discontinuation for high-risk patients, especially those with HCC.

Background/Aims: Liver transplantation is the most effective treatment for the sickest patients with acute-on-chronic liver failure (ACLF). However, the influence of donor age on liver transplantation, especially in ACLF patients, is still unclear. Methods: In this study, we used the data of the Scientific Registry of Transplant Recipients. We included patients with ACLF who received liver transplantation from January 1, 2007, to December 31, 2017, and the total number was 13,857. We allocated the ACLF recipients by age intogroup I (donor age ≤17 years, n=647); group II (donor age 18–59 years, n=11,423); and group III (donor age ≥60 years, n=1,787). Overall survival (OS), graft survival, and mortality were com-pared among the three age groups and the four ACLF grades. Cox regression was also analyzed. Results: The 1-, 3-, and 5-year OS rates were 89.6%, 85.5%, and 82.0% in group I; 89.4%, 83.4%, and 78.2% in group II; and 86.8%, 78.4%, and 71.4% in group III, respectively (p<0.001).When we analyzed the different effects of donor age on OS with different ACLF grades, in groupsII and III, we observed statistical differences. Finally, the cubic spline curve told us that the relative death rate changed linearly with increasing donor age. Conclusions Donor age is related to OS and graft survival of ACLF patients after transplanta-tion, and poorer results were associated with elderly donors. In addition, different donor ages have different effects on recipients with different ACLF grades.

Background/Aims: Liver transplantation is the most effective treatment for the sickest patients with acute-on-chronic liver failure (ACLF). However, the influence of donor age on liver transplantation, especially in ACLF patients, is still unclear. Methods: In this study, we used the data of the Scientific Registry of Transplant Recipients. We included patients with ACLF who received liver transplantation from January 1, 2007, to December 31, 2017, and the total number was 13,857. We allocated the ACLF recipients by age intogroup I (donor age ≤17 years, n=647); group II (donor age 18–59 years, n=11,423); and group III (donor age ≥60 years, n=1,787). Overall survival (OS), graft survival, and mortality were com-pared among the three age groups and the four ACLF grades. Cox regression was also analyzed. Results: The 1-, 3-, and 5-year OS rates were 89.6%, 85.5%, and 82.0% in group I; 89.4%, 83.4%, and 78.2% in group II; and 86.8%, 78.4%, and 71.4% in group III, respectively (p<0.001).When we analyzed the different effects of donor age on OS with different ACLF grades, in groupsII and III, we observed statistical differences. Finally, the cubic spline curve told us that the relative death rate changed linearly with increasing donor age. Conclusions Donor age is related to OS and graft survival of ACLF patients after transplanta-tion, and poorer results were associated with elderly donors. In addition, different donor ages have different effects on recipients with different ACLF grades.

Background/Aims: Liver transplantation is the most effective treatment for the sickest patients with acute-on-chronic liver failure (ACLF). However, the influence of donor age on liver transplantation, especially in ACLF patients, is still unclear. Methods: In this study, we used the data of the Scientific Registry of Transplant Recipients. We included patients with ACLF who received liver transplantation from January 1, 2007, to December 31, 2017, and the total number was 13,857. We allocated the ACLF recipients by age intogroup I (donor age ≤17 years, n=647); group II (donor age 18–59 years, n=11,423); and group III (donor age ≥60 years, n=1,787). Overall survival (OS), graft survival, and mortality were com-pared among the three age groups and the four ACLF grades. Cox regression was also analyzed. Results: The 1-, 3-, and 5-year OS rates were 89.6%, 85.5%, and 82.0% in group I; 89.4%, 83.4%, and 78.2% in group II; and 86.8%, 78.4%, and 71.4% in group III, respectively (p<0.001).When we analyzed the different effects of donor age on OS with different ACLF grades, in groupsII and III, we observed statistical differences. Finally, the cubic spline curve told us that the relative death rate changed linearly with increasing donor age. Conclusions Donor age is related to OS and graft survival of ACLF patients after transplanta-tion, and poorer results were associated with elderly donors. In addition, different donor ages have different effects on recipients with different ACLF grades.

Background/Aims: Liver transplantation is the most effective treatment for the sickest patients with acute-on-chronic liver failure (ACLF). However, the influence of donor age on liver transplantation, especially in ACLF patients, is still unclear. Methods: In this study, we used the data of the Scientific Registry of Transplant Recipients. We included patients with ACLF who received liver transplantation from January 1, 2007, to December 31, 2017, and the total number was 13,857. We allocated the ACLF recipients by age intogroup I (donor age ≤17 years, n=647); group II (donor age 18–59 years, n=11,423); and group III (donor age ≥60 years, n=1,787). Overall survival (OS), graft survival, and mortality were com-pared among the three age groups and the four ACLF grades. Cox regression was also analyzed. Results: The 1-, 3-, and 5-year OS rates were 89.6%, 85.5%, and 82.0% in group I; 89.4%, 83.4%, and 78.2% in group II; and 86.8%, 78.4%, and 71.4% in group III, respectively (p<0.001).When we analyzed the different effects of donor age on OS with different ACLF grades, in groupsII and III, we observed statistical differences. Finally, the cubic spline curve told us that the relative death rate changed linearly with increasing donor age. Conclusions Donor age is related to OS and graft survival of ACLF patients after transplanta-tion, and poorer results were associated with elderly donors. In addition, different donor ages have different effects on recipients with different ACLF grades.