Objective　To observe some biological features of bone marrow mesenchymal stem cells and explore the best conditions for isolatin g and culturing in vitro. Methods　Common cell culture techn ique, light and electron microscopy were used to study the effects of the growth , proliferation, morphology of the bone marrow mesenchymal stem cells in differe nt adherent time, concentration of serum and cell density. Results　The best culture condition in vitro for growth was 4-24 hours adherent time, 5%-10% fetal bovine serum, (4-8)×104/ml cell density. The cells were sp indle in shape and had a strong ability of proliferation. The time for cell duplication was 3 to 4 days. The cells showed the characteristics of stem cell s in electron microscope. Conclusion　The best condition for iso lation and culture of bone marrow mesemchymal stem cells was successfully establ ished and some biological features were obserred. It found a base for further in vestigation and using of mesenchymal stem cells.

Programmed death receptor-1 inhibitor pembrolizumab can restore the function of T cell activity and enhance the anti-tumor immune response by inhibiting the binding of PD-1 to its ligand PD-L1 and blocking the negative regulation of signal pathway. The activated T cells may cause immune-mediated adverse events in the process of anti-tumor. This article reported the severe immune related adverse effects induced by PD-1 inhibitor, pembrolizumab, in a patient with advanced ampullar carcinoma. The patient eventually died due to liver injury, leukocytosis,thrombocytopenia,and disseminated intravascular coagulation (DIC). This article reviewed the diagnosis and treatment of the patient, and reviewed the relevant literatures.

OBJECTIVETo understand the risk factors on severe acute respiratory syndrome (SARS) among their contacts and to develop effective strategy for its control.

METHODSAvailable epidemiological data of SARS cases and close contacts were reviewed and analyzed by SPSS.

RESULTSOut of the 2195 close contacts, 138 (6.3%) were diagnosed as SARS. Among colleagues and classmates of SARS patients, the infection rate was 0.36% versus 31.71% in contacts among families and hospitals, 0.77% in schools. No one was infected among 459 close contacts to SARS in the working unit.

CONCLUSIONSAmong close contacts, factors that facilitating transmission would include: time, extent, frequency and place of contact to the patients, as well as factors related to close contacts as way, time of isolation and age. One of the epidemiological characteristics was that SARS were as clustered in the family among those close contacts. It is important to control the spread of SARS through supervision on the close contacts to patients.

Adult ; Aged ; China ; epidemiology ; Contact Tracing ; Cross Infection ; transmission ; Family Health ; Female ; Humans ; Infectious Disease Transmission, Patient-to-Professional ; Male ; Middle Aged ; Patient Isolation ; Quarantine ; statistics & numerical data ; Retrospective Studies ; Risk Factors ; Severe Acute Respiratory Syndrome ; epidemiology ; prevention & control ; transmission

Rheumatoid arthritis (RA) is an autoimmune disease driven by antigens and mediated by T cells. Collagen II (CII) and fibrinogen (Fib) are the two main antigens in the pathogenesis of RA. The antigen produced after citrulline modification (Cit) is also one of the inducements to induce the body to produce a pathogenic anti-citrulline protein antibody (ACPA). To provide a reference for RA-related research, this study intends to establish an RA animal model by using CII, Cit-CII, Fib, and Cit-Fib antigens, emulsification with complete Freund's adjuvant and immunization with DBA/1 mice, respectively, to compare the pathological characteristics of RA models induced by different antigens from the aspects of pathology, imaging and serum biochemistry. Animal welfare and experimental process are in accordance with the regulations of the Experimental Animal Ethics Committee of the China Academy of Chinese Medical Sciences. The results showed that the CII, Cit-CII, and Cit-Fib induced mice all had symptoms such as joint redness and swelling, and toe deformation and the clinical score and incidence rate were higher than those of the normal group. The CII group had the most serious lesions, with a incidence rate of 100%, and the Cit-CII and Cit-Fib groups had mild symptoms, with a incidence rate of 25% and 37.5%, respectively; pathological and imaging examination results showed that the joints of mice in CII-induced group showed severe synovial inflammation, cartilage and bone destruction, while those in Cit-CII and Cit-Fib group showed only slight inflammatory infiltration, joint cavity stenosis and bone destruction; the results of serum antibody detection showed that CII, Cit-CII and Cit-Fib groups all produced high levels of anti-cyclic citrullinated peptide (CCP) antibodies, among which, Cit-Fib group > Cit-CII group > CII group > Fib group, and both Cit-CII and Cit-Fib groups produced high levels of citrullinated epitope-specific antibodies, while the total IgG level was the highest in CII group; serum ELISA and RT-PCR analysis of joint tissue showed that the expression of pro-inflammatory factors and bone destruction-related molecules increased most significantly in the CII-induced group, followed by Cit-Fib and Cit-CII. The above results showed that among the four different antigens, the symptoms and conditions of arthritis in RA mice induced by CII were the most serious, and IgG instead of anti-CCP antibody was its typical immunological feature, and CII could be the first choice for the model of RA mice; Cit-Fib has certain immunogenicity, can partially induce the symptoms and conditions of RA arthritis in mice, and produce high-level anti-CCP antibody and anti-Cit-Fib antibody, which is more suitable for the study of citrulline-related RA; although Cit-CII has certain immunogenicity, the incidence, and severity of RA arthritis induced by Cit-CII in mice are low.