Hematopoietic stem cells (HSCs) are tissue specific stem cells that replenish all mature blood lineages during the lifetime of an individual. Hematopoietic cell clusters in the aorta of vertebrate embryos play a pivotal role in the formation of the adult blood system. Recently, people have learned a lot about the embryonic HSCs on their development and homing. During their differentiation, HSCs are regulated by the transcription factors, such as Runx1 and Notch signaling pathway, etc. MicroRNAs also regulate the self-renewal and differentiation of hematopoietic stem/progenitor cells on the post-transcriptional levels. Since the onset of circulation, the formation of HSCs and their differentiation into blood cells, especially red blood cells, are regulated by the hemodynamic forces. It would be of great significance if we could treat hematologic diseases with induced HSCs in vitro on the basis of fully understanding of hemotopoietic stem cell development. This review is focused on the advances in the research of HSCs' development and regulation.
Blood Cells ; cytology ; Cell Differentiation ; Embryonic Stem Cells ; cytology ; Hematopoietic Stem Cells ; cytology ; Humans ; Signal Transduction ; Transcription Factors ; physiology

With the improvement of living conditions,people pay more attention to food sanitation,following which the incidence rate of food allergy is higher and higher.Food allergy threatens public health seriously.It is caused mainly by dominance of T helper type 2-based immune responses,which breaks the dynamic balance of Th1/Th2 immune responses and resultes in over secreting of IL-4,IL-5 and IL-13,production of specific antibody IgE,degranulation of mast cells,alteration of intestinal microflora and so on.At present,a lot of investigations have been reported,of which the probiotics therapy attracted more attention.As the indigenous flora,probiotics could not only prevent and treat food allergy but could also modulate immune responses and recover the dynamic balance of it via secreation of cytokines such as IFN-?,IL-10,TGF-?.

Background Recent researches show that oxidative stress is involved in the progress of keratoconus.Nuclear factor-E2-related factor 2-antioxidant response element (Nrf2-ARE) pathway plays a critical role in the defense against oxidative stress,but its function in keratoconus is unclear.Objective To investigate the differences of Nrf2-ARE signaling activation and matrix degenerating enzymes between keratoconus and normal corneal stromal cells.Methods Corneal stromal cells were isolated from keratoconus and normal cornea by using dispase and collagenase digestion.The cells were treated with hydrogen peroxide (H2O2) to mimic in vivo oxidative stress condition.Reactive oxygen species (ROS) production was measured by fluorescence substrate DCHF-DA incubation.Nrf2 level and the expression of Nrf2-ARE downstream antioxidant genes were analyzed by Western blot and real-time quantitative-PCR(RT-qPCR).The activity of matrix degenerating enzymes,including urokinase-type plasminogen activator (uPA)-uPA receptor (uPAR) system and matrix metalloproteinase-2 (MMP-2) were assessed by Western blot and gelatin zymography respectively.Results In normal culture,keratoconus corneal stromal cells assumed increased basal ROS and Nrf2 level when compared with normal cells(t =18.155,P＜0.01).However,after H2O2 treatment,the keratoconus corneal stromal cells showed increased ROS production,while decreased Nrf2 translocation and no significant difference in expression levels of Nrf2-ARE downstream antioxidant genes (Nrf2:t =62.123,P＜ 0.01 ; (nicotinamide adenine dinucleotide phosphate quinine oxidoreductase-1 [NQO-1]:t =2.209,P =0.092 ; hemo oxygenase-1 [HO-1]:t =0.293,P =0.784 ; superoxide dismutase [SOD2]:t =0.749,P =0.495).The contents of uPA-uPAR and the activity of MMP-2 also showed a higher level in keratoconus corneal stromal cells than normal cells,with significant differences between them (t =19.164,15.458,4.818,all at P＜0.01).Conclusions The defect of Nrf2-ARE signaling activation exists in the keratoconus corneal stromal cells,and correlats with the abnormal expression level of stromal degeneration enzymes,which suggests that the defect of Nrf2-ARE signaling activation may be involved in the progression of keratoconus.

Objective:To systematically evaluate the clinical efficacy of programmed death-1 and programmed death ligand 1 (PD-1/PD-L1) inhibitors versus traditional first-line regimens for the treatment of solid tumors.Methods:Databases including PubMed, Embase and Cochrane Library were searched for literatures from the date of their establishment to October 2018 with the key words including "PD-1/PD-L1, solid tumors, melanoma, non-small cell lung cancer, renal cell carcinoma, immunotherapy" . The randomized controlled trial or non randomized controlled trial of high quality about PD-1/PD-L1 inhibitors and traditional fist-line regimens for the treatment of solid tumors were received and enrolled. Patients underwent PD-1/PD-L1 inhibitors immunotherapy were allocated into treatment group, patients underwent traditional first-line regimens treatment were allocated into control group. Two reviewers independently screened literatures, extracted data and assessed the risk of bias. Count data were described as odds ratio ( OR) and 95% confidence interval (95% CI). The heterogeneity of the studies included was analyzed using the I2 test. Funnel plot was used to test potential publication bias if the studies included≥5, and no test was needed if the studies included<5. Results:(1) Document retrieval: a total of 11 available randomized clinical trials were included. There were 5 161 patients, including 2 677 in the treatment group and 2 484 in the control group. (2) Results of Meta analysis. ① There was a significant difference in the objective response rate between the treatment group and the control group ( OR=4.49, 95% CI: 3.01-6.68, P<0.05). The bilateral symmetry was presented in the funnel plot based on the 9 studies, suggesting that publication bias had little influence on results of Meta analysis. ② There was no significant difference in the disease control rate between the treatment group and the control group ( OR=1.53, 95% CI: 1.01-2.32, P=0.05). The bilateral symmetry was presented in the funnel plot based on the 9 studies, suggesting that publication bias had little influence on results of Meta analysis. ③ There was a significant difference in disease stability rate between the treatment group and the control group ( OR=0.49, 95% CI: 0.33-0.73, P<0.05). The bilateral symmetry was presented in the funnel plot based on the 9 studies, suggesting that publication bias had little influence on results of Meta analysis. ④ There was no significant difference in disease progression rate between the treatment group and the control group ( OR=0.71, 95% CI: 0.45-1.15, P>0.05). The bilateral symmetry was presented in the funnel plot based on the 9 studies, suggesting that publication bias had little influence on results of Meta analysis. ⑤ There were significant differences in overall incidence of adverse events and incidence of adverse events not less than three levels between the treatment group and the control group ( OR=0.53, 0.54, 95% CI: 0.38-0.74, 0.31-0.93, P<0.05). The bilateral symmetry was presented in the funnel plot based on the 11 studies, suggesting that publication bias had little influence on results of Meta analysis. Conclusion:Compared with traditional first-line regimens treatment, PD-1/PD-L1 inhibitors immunotherapy can improve the objective response rate and decrease the incidence of adverse events.

Objective:To develop a Risk Assessment Index System (RAIS) on HIV infection among young students based on Delphi method and to provide individual HIV infection risk assessment, targeted prevention and control measures.Methods:Delphi method was applied to determine the index system and weight of the assessment tool through three rounds of expert consultation and overall consideration of opinions and suggestions from 19 experts.Results:The positivity coefficients of three rounds of expert consultation were 100%. The authority coefficient of experts was between 0.887 and 0.945. The Kendall's W coefficients through first, second and third round specialist consultation was 0.379, 0.329 and 0.248, respectively (all P<0.001). The coefficients of variation in the third round were all less than 0.25, indicating that experts' opinion tend to be consistent and the results are highly reliable. The HIV infection risk assessment index system among young students consisted of 7 first grade indices and 54 second grade indices, of which weight was calculated. Conclusions:The RAIS on HIV infection for young students was initially established based on Delphi method, and could be used in the development of HIV infection risk assessment tools for personalized prevention and intervention among young students. However, the reliability, validity and effect of this assessment index system need to be further evaluated.

Objective:To explore the difference of sexual health characteristics and demands in students in different groups, and provide the basis for targeted sexual health eduction for AIDS prevention in young students.Methods:A survey was conducted based on the requirement of health education about sexual health and AIDS prevention in young students by the education department of Guangdong province. A two-step cluster analysis was performed on the survey data obtained by convenient sampling, the variables and number of clusters included were determined by combination of analysis results and professional knowledge. The demographic characteristics, the content and form of sexual health education needed were compared among different groups.Results:Survey data of 3 884 students were collected, and six variables were used for classification: cognition or occurrence masturbation, sexual behavior, frequency of sexual information acquisition, number of acceptable sex partners and AIDS knowledge awareness rate. By these variables, the students were classified into three levels of risk groups: high risk group (46.6%), medium risk group (39.9%) and low risk group (13.5%). As for demographic characteristics, high risk group, with a median age of 19 years, had the highest proportions of boys (65.9%), students with non-heterosexuality orientation (15.2%), urban residents (58.2%), only children (30.8%) and undergraduates (54.7%). Medium risk group, with a median age of 19 years, had the highest proportions of girls (82.7%) and vocational college students (34.0%). Low risk group, with a median age of 18 years, had the highest proportions of rural residents (52.4%), non-only child (80.6%), senior high school students (41.3%), non-boarding students (17.5%) and students without internship and part-time job experience (43.2%). In terms of health education demands, high risk group had a higher demand of information about self-identity, sexual safety, sexual decision making, contraception, abortion, and sexually transmitted disease or AIDS prevention. Medium risk group paid more attention to value on love and marriage, sexual assault. Low risk group showed a higher demand of adolescent physiology knowledge. Compared with low risk group, high risk group had a higher demand of peer education, Internet/multimedia, anonymous counseling and other forms of sexual health education. The differences were significant.Conclusion:The characteristics, sexual knowledge awareness, attitude and behavior, and health education demands of young students in different groups are different, so health education materials and methods should be developed according to the characteristics of different groups to enhance the acceptance and enthusiasm of students and improve the quality of sexual health education.

Objective:To analyze the influencing factors for HIV testing services utilization in students with self-assessed high risk of HIV infection.Methods:The research framework of the influencing factors for HIV testing services utilization in students was developed based on Andersen's health services utilization behavioral model and related literature. A cross-sectional survey was performed in students with self-assessed high risk of HIV infection by an online HIV infection risk assessment tool from March to April 2019. Multiple logistic regressions were applied with hierarchical model.Results:A total of 526 students were included in the study (age: 19.30±1.19 years old), in whom 96.2% agreed that HIV testing should be received after high-risk behavior. 56.7% (298/526) had sexual behavior and the HIV testing rate was 11.0% (58/526). The HIV testing rates in students who had and had no sex behavior were 13.42%(40/298) and 7.89% (18/228), respectively. According to the results from multivariate logistic regression analysis, non-heterosexual (compared with heterosexual, OR=7.88, 95% CI: 3.98-15.61) and higher score of AIDS knowledge awareness (compared with lower score, OR=2.05, 95% CI: 1.07-3.93) in propensity factor module, and having risk sexual behavior (compared with having no risk sexual behavior, OR=2.66, 95% CI: 1.41-5.03) and having diagnosis of STD infection in hospital (compared with having no such diagnosis, OR=6.35, 95% CI: 2.21-18.27) in demand factor module, and receiving health education about AIDS prevention in the past year (compared with receiving no such health education, OR=0.29, 95% CI: 0.11-0.76) and receiving health education about AIDS testing service in the past year (compared with receiving no such health education, OR=3.67, 95% CI: 1.71-7.90) in ability factor module were the influencing factors for utilization of HIV testing services. Conclusions:The acceptance of HIV testing in students needs to be improved urgently. Propensity factors, such as their AIDS knowledge awareness and sexual orientation, and demand factors, such as having risk sexual behavior and STD infection, have obvious impacts on the utilization of HIV testing services. However, health education about AIDS prevention and HIV testing service can play a more important role in facilitating the utilization of HIV testing in students. In the future, we should further strengthen the publicity of voluntary HIV counseling and testing service in students with particular attention to girls and those with risk sexual behaviors.

Objective:To evaluate the effect of "self-categorization" on decision of health preference and the influence of self-categorized deviation in knowledge, attitude and practice (KAP) on the willingness of seeking help for sexual health among young students.Methods:From March to April 2019, young students who used a WeChat applet for sexual health and HIV infection risk assessment, which is called "Detective Bear" were recruited and investigated. According to the consistency between the self-categorization of KAP for sexual health and the systematic categorization from their honest answers, the participants were allocated into three groups: consistent, low or high status, according to their judgment on sexual information acquisition, sexual attitude, and the actual number of sexual experiences. Logistic regression was used to analyze the differences in the willingness to seek help for sexual health problems between the three groups.Results:2 009 students with an average age of (19.2±1.1) were included. 54.7% (1 099/2 009) were female, and 98.4% (1 976/2 009) were college, undergraduate or postgraduate students. 49.0% (984/2 009) were in the consistent group, 10.9% (219/2 009) had a lower self-categorization, 40.1% (806/2 009) had a higher self-categorization. Compared with the consistent group, students with lower self-categorization of KAP for sexual health were less likely to assess HIV voluntary counseling and testing (a OR=0.65, 95% CI: 0.43-0.99). However, students with higher self-categorization seemed to dislike seeking help for sexually transmitted diseases (a OR=0.76, 95% CI: 0.59-0.98). Conclusions:Deviation in self-categorization of KAP for sexual health will reduce the young students' willingness to seek help for related problems. Especially those with lower self-categorization, lack of risk consciousness, and refuse to assess counseling and testing may increase the HIV/AIDS epidemic among this population. It is necessary to strengthen the capacity of self-assessment for young students while promoting sex education.

Objective:To summarize the design and analysis of testing results of a WeChat applet, which is called "Detective Bear", for sexual health and HIV infection risk assessment in young students, and evaluate its feasibility and effectiveness.Methods:Based on self-categorization theory, by using cluster analysis and Delphi expert consulting method, the framework of WeChat applet, risk assessment index system and preventive intervention content were determined. Young students were recruited by student associations for the application test, the results of the repeated tests and the satisfaction survey were collected and analyzed.Results:The study included 393 participants who repeated the test twice and 750 participants who volunteered to participate in the satisfaction questionnaire survey. The applet contains five modules: self-role judgment, self-test, risk assessment, assessment report generation and background management. The risk assessment module contains 6 first-level indicators and 55 second-level indicators. Assessment report generation module includes role diagnosis type, radar chart of HIV sexual health KAP and intervention prescription. In 393 students who repeated the test, the awareness of AIDS to be a serious sexually transmitted disease, the epidemic trend in young students in China, with active seeking HIV testing services and caring the infected improved. The satisfaction survey showed that 75.7% of students (568/750) accepted the applet, 86.5% (649/750) agreed the evaluation report, 83.1%(623/750) thought that there were some problems, but it was easy to use, 93.3% (700/750) said they can learn something from the applet and 84.1% (631/750) satisfied with the page design. Some students thought the questionnaire was too long and somewhat difficult to complete ( P<0.05), and some reported that more can be learned ( P<0.05). Conclusions:The applet integrates AIDS prevention related knowledge and practice into a challenging, interesting, interactive game and provide individualized, concrete risk assessment and self-intervention for young students, which can effectively help students to improve the awareness of AIDS related knowledge and get links for access to condoms, testing and other intervention services. However, its large-scale application and long-term effect need to be further tested.