[ ABSTRACT] AIM:To study the process of promoting mouse embryonic stem cells ( ESC) to specify to definitive endoderm by up-regulating of Nodal signal pathway in order to find the best cultivated systems of differentiation of mouse ESC to definitive endoderm cells.METHODS:The cells were divided into different groups based on the culture medium:ESC group ( serum-free medium +LIF) , natural differentiation group ( serum-free medium) and activin A group ( serum-free medium +50μg/L activin A).The cells and the sterilized coverslips with cells were collected at 1, 3, 5 and 7 d of the cultivation.The proportion of CXCR4 +cells was detected by flow cytometry.The expression of CXCR4 was determined by immunocytochemical method, and the protein expression of OCT4 and CXCR4 was detected by Western blot.RE-SULTS:The proportion of CXCR4 +cells showed no dramatic change in ESC group along with the extending of cultivation day, while there were gradually increased in natural differentiation group and activin A group and the highest level was ob-served at 5 d.Among the 3 groups, the proportion of CXCR4 +cells at 5 d was the highest in activin A group.The brown or tan staining in the cells observed under microscope was considered as positive CXCR4 by immunocytochemistry.The pro-tein levels of OCT4 and CXCR4 in ESC group along with the extending of cultivation days was observed.The expression levels of OCT4 were gradually decreased in the cells in natural differentiation group and activin A group, while those of CX-CR4 were gradually increased with the highest level at 5 d.It was highest in the cells in activin A group.CONCLUSION:The proportion of definitive endoderm was the highest at 5 d of the induction during in vitro mouse ESC differentiation.Up-regulation of Nodal signal pathway by adding activin A at the early stage of mouse ESC differentiation promotes mouse ESC to specify to definitive endoderm with CXCR4 molecular marker.

ObjectiveTo investigate the cumulative incidence of persistent hypothyroidism in patients who were diagnosed as postpartum thyroiditis ( PPT),and to determine the factors associated with the development of persistent hypothyroidism in those patients.MethodsThe present study was performed as the continuous study followed by the former epidemiological survey on PPT,in which 58 patients with PPT (35 overt PPT and 23 subclinical PPT) were diagnosed.The 58 patients were followed up at 12th month postpartum,and then for every 6 months until 24 months postpartum.Fasting blood samples were taken for testing serum TSH,thyroid peroxidase antibody ( TPOAb),and thyroglobulin antibody ( TgAb ).Free T3 ( FT3 ),free T4 ( FT4 ),and TSH receptor antibody ( TRAh ) were detected if TSH was abnormal.50 healthy postpartum women were used as control group.ResultsOf the total 58 PPT patients,91,4％ ( n =53 ) were successfully followed.Five patients with overt PPT and 6 patients with subclinical PPT developed persistent hypothyroidism,and the cumulative incidence of persistent hypothyroidism in the studied PPT patients was 20.8％.Among 15 PPT patients who had a classical biphasic course (a thyrotoxic phase followed by a hypothyroid phase),persistent hypothyroidism was seen in 26.7％ (n =4 ).Among 11 PPT patients with hypothyroidism only,persistent hypothyroidism was seen in 63.6％ ( n =7).On the contrary,none of the patients with thyrotoxicosis only had persistent hypothyroidism.All of the patients who developed persistent hypothyrodism had a higher TSH levels than 4.8 mU/L at 6th month postpartum.Before delivery,TSH levels of the patients developed persistent hypothyroidism were significantly higher than those of the patients with transient hypothyroidism,and this was the case at the 12th month postpartum ( all P＜0.01 ).PPT patients maintained a relatively higher rate of thyroid autoantibodies.The positive rate of TPOAb at the 12th,18th,and 24th month postpartum was 56.6％,50.9％,and 52.8％,respectively; and the positive rate of TgAb being 35.8％,30.2％,and 30.2％,respectively.Both the positive rate and titer of TPOAb in patients with overt PPT were higher than those in patients with subclinical PPT at the 18th and 24th month postpartum (P＜0.05).Conclusions 20.8％ patients with PPT developed persistent hypothyroidism at the 24th month postpartum.Whether a patient with PPT would develop persistent hypothyroidism depends on his clinical feature and TSH level.

Objective To analyze the chemical constituents in the water extract of Bupleuri Radix and investigate the active ingredients of Bupleuri Radix for the treatment of depression.Methods The chemical constituents in the water extract of Bupleuri Radix were identified by Ultra-high-performance liquid chromatography coupled with quadrupole time-of-flight mass spectrometry(UPLC-Q-TOF/MS).CORT-induced poorly differentiated PC12 depression cell model was launched,and PC12 cells were pretreated with monomeric compounds from Bupleuri Radix for 24 h.The cell viability and LDH release rate were measured by CCK-8 assy kit and LDH assay kit,respectively.Results A total of 53 compounds were identified in the water extract of Bupleuri Radix,mainly including type Ⅰ,type Ⅱ and type Ⅲsaikosaponins.Among them,saikosaponin A,saikosaponin B2,saikosaponin C,saikosaponin E,saikosaponin F and 6″-acetyl saikosaponin A contributed the most to the metabolite profile of Bupleuri Radix,and could improve the viability of CORT-induced PC12 cells(P<0.05,P<0.01).Furthermore,saikosaponin A,saikosaponin B2,saikosaponin C,saikosaponin E and saikosaponin F could decrease the LDH release rate of CORT-induced PC12 cells(P<0.05,P<0.01).Conclusion The major anti-depression active ingredients in Bupleuri Radix may be Saikosaponin A,saikosaponin B2,saikosaponin C,saikosaponin E and saikosaponin F,which lays a foundation for the research of the quality control and pharmacodynamic material basis of Bupleuri Radix.

Background: Cardiopulmonary resuscitation (CPR) strategies in COVID-19 patients differ from those in patients suffering from cardiogenic cardiac arrest. During CPR, both healthcare and non-healthcare workers who provide resuscitation are at risk of infection. The Working Group for Expert Consensus on Prevention and Cardiopulmonary Resuscitation for Cardiac Arrest in COVID-19 has developed this Chinese Expert Consensus to guide clinical practice of CPR in COVID-19 patients. Main recommendations: 1) A medical team should be assigned to evaluate severe and critical COVID-19 for early monitoring of cardiac-arrest warning signs. 2) Psychological counseling and treatment are highly recommended, since sympathetic and vagal abnormalities induced by psychological stress from the COVID-19 pandemic can induce cardiac arrest. 3) Healthcare workers should wear personal protective equipment (PPE). 4) Mouth-to-mouth ventilation should be avoided on patients suspected of having or diagnosed with COVID-19. 5) Hands-only chest compression and mechanical chest compression are recommended. 6) Tracheal-intubation procedures should be optimized and tracheal-intubation strategies should be implemented early. 7) CPR should be provided for 20-30 min. 8) Various factors should be taken into consideration such as the interests of patients and family members, ethics, transmission risks, and laws and regulations governing infectious disease control. Changes in management: The following changes or modifications to CPR strategy in COVID-19 patients are proposed: 1) Healthcare workers should wear PPE. 2) Hands-only chest compression and mechanical chest compression can be implemented to reduce or avoid the spread of viruses by aerosols. 3) Both the benefits to patients and the risk of infection should be considered. 4) Hhealthcare workers should be fully aware of and trained in CPR strategies and procedures specifically for patients with COVID-19.