Objective: In in vitro systems for differentiating and expanding natural killer (NK) cells, feeder cells provide essential cell-cell contact and paracrine signals that drive precursor proliferation and terminal maturation. However, existing xenogeneic feeder cells or tumor-derived genetically modified feeder cells pose risks of residual immunogenicity and malignant transformation, limiting clinical use. This study aims to develop a humanized mesenchymal-like stromal cell (hematopoietic organoid-derived human mesenchymal stromal cells, HO-hMSCs) derived from iPSC-based hematopoietic organoids, and elucidate its mechanisms of NK-supportive activity to enable a safe, efficient platform for clinical-grade NK cell production. Methods: Human induced pluripotent stem cells (iPSCs) were differentiated into hematopoietic organoids, from which HO-hMSCs were isolated. Flow-cytometric phenotyping and bulk RNA-sequencing were performed to compare HO-hMSCs with umbilical cord-derived MSCs (UC-hMSCs). The effect of HO-hMSCs on NK cell differentiation efficiency (CD3 CD56 ) and effector maturation (CD16 expression) were assessed by co-culture experiments, using UC-hMSCs as control. Results: 1) Hematopoietic organoid induction and NK differentiation: iPSCs were induced to form hematopoietic organoids using cytokine cocktails, which further differentiated into high-purity CD45 CD56 NK cells [(82.8%±12.07)% efficiency on day 21]. 2) HO-hMSC characteristics: HO-hMSCs exhibited upregulated expression of Notch pathway ligands (DLL4, JAG1, 4.06-8.04-fold), homeobox genes (HOXA3, HOXA5, log FC=1.28 and 1.44), and key regulators of NK development (GATA3, BCL11A) and cytokine receptors (IL7R, IL27RA, 6.76 to 13.34-fold increase). 3) Functional validation: Compared to UC-hMSCs, HO-hMSCs co-culture significantly enhanced NK cell proportion by 30.5% (P<0.05) and increased CD16 positivity (+20.5%). Conclusion: This study for the first time reveals that human hematopoietic organoid-derived HO-hMSCs possess potent hematopoietic niche-supportive activity. It provides a humanized, feeder-free platform for robust clinical-grade NK cell production and expands the translational utility of organoid technologies in cell therapy.

Objective To investigate the predict value of imaging parameters in computed tomography perfusion(CTP)combined with computed tomography angiography(CTA)examination and serum biomarkers for recurrent stroke events at three-month and one-year follow-ups.Methods A total of 136 patients with cerebral infarction diagnosed for the first time were included in the retrospective study.These patients received CTA+CTP one-stop examination and serum biomarkers testing,followed by three-month and one-year follow-ups for the occurrence of recurrent stroke events.Recurrent stroke events were defined as ischemic stroke,retinal infarction,intracerebral hemorrhage,subarachnoid hemorrhage,and death.Results The recurrent stroke events rate was 23.5%(32 cases)and 36.8%(50 cases)at three-month and one-year follow-ups,respectively.Ischemic penumbra(IP)volume[odds ratio(OR)=1.010,P=0.029]and modified Rankin scale(mRS)score at discharge(OR=1.388,P=0.008)were independent predictors for recurrent stroke events at the three-month follow-up,so were lipoprotein(a)[Lp(a)](OR=1.002,P=0.044),vascular stenosis severity(OR=1.489,P=0.029),and mRS score at discharge(OR=1.282,P=0.038)at the one-year follow-up.Conclusion Among patients with stroke diagnosed for the first time,IP volume,Lp(a),vascular stenosis severity and mRS score at discharge are the most powerful predictors of recurrent stroke events at three-month and one-year follow-ups.

Objective To explore the correlation value of high-resolution MRI on the cause,location and degree of nerve root com-pression and clinical symptoms of lumbar intervertebral foramen stenosis.Methods Patients with sciatic neuralgia underwent con-ventional MRI examination of the lumbar spine before treatment.MRI thin layer(1 mm)intervertebral disc axial scan was performed on patients with suspected L4/L5 and L5/S1 intervertebral foramen stenosis,and the value of conventional MRI and high-resolution MRI on intervertebral foramen stenosis location,etiology and Elisabeth typing was compared and analyzed.Intervertebral foramen mor-phometric indicators,nerve root length and short diameter were measured on high-resolution MRI post-processed images and their correlation with visual analogue scale(VAS)scores of clinical symptoms was analyzed.Results Sixty-one patients were effectively diagnosed with intervertebral foramen stenosis and nerve root compression after surgery or conservative treatment.The diagnosis rate of conventional MRI for the cause of intervertebral foramen stenosis was 75.4％,and the diagnosis rate of high-resolution MRI post-processed was 91.8％.The Elisabeth typing of lumbar intervertebral foramen stenosis was positively correlated with clinical symp-toms,while the nerve root short diameter and peri-nerve fat space area were negatively correlated with VAS score.Conclusion High-resolution MRI is significantly better than conventional MRI for the diagnosis of nerve root compression in intervertebral fora-men stenosis.It visually shows the location,cause and degree of nerve root compression,which can better guide the clinical and accu-rate minimally invasive surgery.

Objective Utilizing a specially engineered miR-144-GFP-H1 human embryonic stem cell(hESC)reporter line,this study leverages GFP fluorescence as an indicator of miR-144 expression to gauge the progression of erythropoiesis.The investigation is aimed at elucidating the potential roles of lncRNAs within the erythropoietic framework and conducting an initial assessment of their functional impact.Methods The miR-144/451-GFP-H1 cell line(hereafter referred to as 144-H1)was utilized for in vitro erythrocyte induction culture.The subpopulations of cells entering the erythropoiesis stage were characterized by the surface molecules CD71 and GPA.The GFP reporter gene of miR-144 served as a critical determi-nant to distinguish between GFP-positive cells(with a high propensity for erythropoiesis)and GFP-negative cells(with a low propensity for erythropoiesis).Transcriptome sequencing was performed on both groups to identify differentially ex-pressed long non-coding RNAs(lncRNAs).LncRNA entries with potential for validation were selected for preliminary func-tional verification.The CRISPR/Cas9 gene editing technique was employed to design functional interference strategies for the targeted lncRNAs,obtaining 144-H1 cell lines with knocked-out function of the specific lncRNAs.These knockout cell lines,along with non-knockout 144-H1 cell lines,were used for parallel erythrocyte induction culture to identify differential nodes.This approach preliminarily verified their impact on erythropoiesis in an in vitro development model.Results 1)The constructed 144-H1 cell line was capable of expressing GFP fluorescence upon entering the stage of in vitro erythrocyte in-duction,indicating the activation of miR-144/451.2)Within the CD71,GPA double-positive group,significant differences in lncRNA expression were observed between the GFP-positive and GFP-negative subpopulations.3)Gene editing strategies involving the deletion of sequence segments capable of effectively interfering with the function of multiple lncRNA entries were designed and verified for successful editing.In the knockout cell lines,parts of the lncRNA sequences were directly de-leted.4)In parallel validation experiments of erythrocyte induction culture,cell lines with LINC01569 knocked out exhibited significant differences in flow cytometric subpopulations and cell proliferation capabilities compared to the non-knockout cell lines:①The knockout cell lines showed sustained high expression of GFP fluorescence.②The proportion of the CD71-GPA double-positive group in the knockout cell lines continuously decreased during erythrocyte maturation.③No significant ex-pression of hemoglobin was observed in the knockout cell lines,lacking the characteristic red color.④The cell proliferation capability of the knockout cell lines was significantly lower than that of the non-knockout cell lines(P＜0.05).Conclusion The successful employment of the 144-H1 cell line facilitated an exploration into the potential functions of lncRNAs in e-rythropoiesis.This enables the design of more refined in vitro developmental experiments to enhance the precision in captu-ring lncRNA functions.Among the differentially expressed lncRNA entries,LINC01569 was preliminarily validated to play a regulatory role in erythropoiesis.The functional absence of LINC01569 severely impacts the normal differentiation and prolif-eration of erythrocytes.The specific regulatory mechanism of LINC01569 in erythropoiesis warrants further investigation and research.

Objective:To investigate the characteristics of digestive system symptoms and its relation with the time of nucleic acid continuous positive in population infected with severe acute respiratory syndrome coronavirus 2 Omicron variant, and to analyze the abdominal computed tomography (CT) features of patients infected with Omicron variant.Methods:From April 11 to May 23, 2022, a questionnaire survey was conducted in patients infected with Omicron variant admitted to the Shanghai National Convention and Exhibition Center Fangcang Hospital. The questionnaire included basic information, the start time of nucleic acid positive, respiratory symptoms, digestive system syptoms and outcomes, etc.Combined with the clinical data, the relation between digestive tract symptoms and the time of nucleic acid continuous positive were analyzed. Thoracic and abdominal CT were performed for patients with continuous positive nucleic acid results ≥10 d, and the relationship between the abdominal CT imaging characteristics and the time of nucleic acid continuous positive was analyzed. Independent sample t-test and multivariate logistic regression were used for statistical analysis. Results:A total of 4 360 valid questionnaires were collected, including 2 475 males and 1 885 females, with a hospital stay of (6.8±4.9) d. Among the 4 360 patients, 1 979 patients (45.4%) had gastrointestinal symptoms such as loss of appetite, abdominal discomfort or pain, constipation and diarrhea. The time of nucleic acid continuous positive in patients with gastrointestinal symptoms was (7.4±5.5) d, which was longer than that of patients without gastrointestinal symptoms (6.5±3.6) d, and the difference was statistically significant ( t=3.78, P<0.001). During the isolation period in the Fangcang Hospital, the time of nucleic acid continuous positive in patients with complete remission of digestive tract symptoms was shorter than that of patients with no remission of digestive tract symptoms ((7.3±5.2) d vs. (8.5±5.7) d), and the difference was statistically significant ( t=2.25, P=0.025). The results of multivariate logistic regression analysis showed that the combination of gastrointestinal symptoms was an independent risk factor for continuous positive nucleic acid result ≥10 d ( OR=1.316, 95% confidence interval 1.294 to 2.205, P=0.046). Among the 299 patients with continuous positive nucleic acid results≥10 d, 187 cases (62.5%) had gastrointestinal symptoms, and 146 cases (48.8%) had abdominal CT findings of thickening of the gastroduodenal wall, thickening of the small intestinal wall, indistinct mesenteric vessels of the small intestine, and dilatation and pneumatosis of the colon. In patients with continuous positive nucleic acid results ≥10 d, abdominal CT indicated that patients with gastrointestinal imaging changes had a longer time of nucleic acid continuous positive than those without gastrointestinal imaging changes ((16.0±2.8) d vs. (13.0±2.1) d), and the difference was statistically significant ( t=2.62, P=0.009). Conclusions:Digestive system symptoms are common in patients infected with Omicron variant. The time of nucleic acid continuous positive in patients with gastrointestinal symptoms is longer than those without gastrointestinal symptoms. Some patients may have gastrointestinal lesions on abdominal CT.

Medical microbiology experiment is faced with many problems in online teaching. This study adopts the teaching mode of online live broadcast + operation video + virtual experiment, and make up the operation gap to some extent through operation video and virtual experiment. The mode of assessment is subjective thinking question (closely following the operation process) + experiment design + literature review (focusing on the key technology or new technology of clinical assessment that cannot be carried out due to the limitation of conditions in traditional experiments, such as mass spectrometry, fluorescence quantitative PCR, and G-test), and it is helpful to understand students' mastery of teaching objectives, and the ability of comprehensive application and innovative thinking. The student questionnaire shows that most students hold a positive attitude towards the online experimental teaching mode, and the quality of students' homework shows that most students have a good learning effect.

Objective: In this study, black tea and Citrus maxima (BT-CM), yellow tea and C. maxima (YT-CM), green tea and C. maxima (GT-CM) as subjects, the active ingredient content and antioxidant activity of three tea and C. maxima (T-CM) were analyzed. The effects of three T-CMs on apoptosis of liver cells in vitro and its mechanism were further explored. Methods: National standard method and HPLC were used for active ingredient analysis. MTT, cell flow cytometry and Western blot were used to analyze the effects of three T-CMs on cell proliferation, apoptosis, and its underlying molecular mechanism. Results: The content of tea polyphenols, free amino acids, ratio of polyphenols and amino acids, ester catechins, non-ester catechins and caffeine in YT-CM and GT-CM was significantly higher than that of BT-CM. The in vitro antioxidant capacity of YT-CM and GT-CM was also significantly stronger than that of BT-CM. Three T-CMs had the effects of inhibiting proliferation, arresting cell cycle and inducing apoptosis in HepG2 and Bel7402 cells, especially YT-CM and GT-CM. Western blot analysis showed three T-CMs activated PI3K/AKT/mTOR signaling pathway and regulated the expression levels of apoptosis-related proteins Bax, Bcl-2 and Caspase-3/9. YT-CM and GT-CM had better ability to change the signal pathway than BT-CM. Conclusion: In short, T-CMs, which combined different degrees of fermentation tea with C. maxima, were rich in nutrients and biologically active substances. T-CMs, especially YT-CM and GT-CM, are healthy drinks that help to prevent and treat liver cancer.

Five universities with health policy and management ranked top level worldwide, including Harvard University, John Hopkins University, Stanford University, University of North Carolina at Chapel Hill and National University of Singapore were selected in our study. From above universities, we found that the curriculum of PHD students was focused on research concentration, methodology courses, and numerous elective courses. Hence, in China, the curriculum of PHD students should be improved with emphasis on course studying, management courses and highlighting curriculum content according to research area to enhance the quality of doctoral education.

Objective:To explore the competency for the assistant general practitioners in China to provide theoretical support for the construction of the post competence model of assistant general practitioners and training and evaluation of assistant general practitioners.Methods:During January 22 to June 18, 2019, Using snowball sampling method and behavioral event interviews, 23 general practitioners and assistant general practitioners were interviewed in China, including 14 general practitioners in the superior performance group and 9 assistant general practitioners in the average performance group. The interview contents were coded and analyzed, and the statistical methods of t test and rank sum test of two independent samples were used to screen competency characteristics and construct the competence model of assistant general practitioners.Results:The total classification consistency and the total coding reliability coefficient was respectively 0.79, 0.87. 59 competency characteristics of assistant general practitioners were obtained including 3 differentiated competency characteristics "Understanding the medical and health system and related policies", "Critical thinking skills" and "General practitioner clinical thinking" and 10 baseline competency characteristics. There was no statistically significant difference between the average performance group and the superior performance group in the total frequency of competency [(29.4±12.7) times to (23.4±7.0) times, t=1.27, P=0.22]. Conclusion:The preliminary competency characteristics of assistant general practitioners have good reliability and can provide references for further exploration of the competency model.

Objective: To understand the demand of rural parents for children’s sexual education knowledge and associated factors, to provide reference and advise for the development of the children’s sexual education in the rural areas. Methods: In this study,1 015 parents from 16 rural kindergartens in Luzhou City and Mianyang City were selected as the research objects by multiple-stage stratified sampling from March to May, 2019. The self-interview or face-to-face questionnaire survey was used to investigate the demand for children’s sexual education among parents. Results: Totally 81.7%(829) of parents expressed their demand for children’s sexual education knowledge. Multivariate logistic regression analysis showed that age was negatively associated with demand for sexual education of children(OR=0.73,95%CI=0.61-0.88). Junior middle school education background of mothers(OR=2.45,95%CI=1.36-4.41), received sexual education for children(OR=2.85，95%CI=1.84-4.42), reckon sexual education for children as necessary(OR=4.97，95%CI=3.16-7.83)and regarded it as parents’ own responsibility(OR=2.11，95%CI=1.30-3.43) had a high demand for children’s sexual education knowledge(P<0.05). Conclusion Parents in Sichuan rural areas generally have a high demand for children’s sexual education. We should intensify publicity and training about sexual education knowledge among parents in rural areas and attach importance to the cooperation between family and kindergarten in order to jointly promote the development of children’s sexual education.