BACKGROUNDIn recent years, many progresses have been made in molecular target therapy for lung cancer, in which anti-angiogenic target therapy is a hot spot drawing researchers' attention. The aim of this study is to explore the expression of canstatin gene transfected into human lymphocytes and its inhibitory effect on growth and metastasis of Lewis lung carcinoma.

METHODSThe eukaryotic expression vector of pCMV-Script and the recombinant pCMV-Script/Canstatin vector were separately transfected into lymphocytes by electroporation. The expression of canstatin protein in supernatant of lymphocyues was examined by SDS-PAGE assay. Furthermore, Lewis lung carcinoma cells were subcutaneously inoculated to C57BL mice to make animal model of tumor. When the transplanted tumors on the mice developed to 1cm³, the 30 mice were randomized into 3 groups, which were injected with 0.2mL supernatant of lymphocytes transfected with recombinant vector or naked vector, or 0.2mL NS respectively. After the treatment for 14 days, the size and pathological section of subcutaneous tumors were observed, and the number of pulmonary metastatic node was calculated.

RESULTSCanstatin protein was found in supernatant of the lymphocytes in the recombinant vector group by SDS-PAGE assay. After the treatment, the tumor size in the recombinant vector group (1.49cm³±0.18cm³) was significantly smaller than that in the naked vector group (2.44cm³± 0.19cm³) and NS group (2.53cm³±0.18cm³) (P=0.000). The numbers of pulmonary metastatic node were 3.40±1.14, 7.60±2.61 and 7.60±2.41 in the recombinant vector group, naked vector group and NS group respectively (recombinant vector group vs the other two groups, P=0.013).

CONCLUSIONSThe pCMV-Script/Canstatin vector can express canstatin protein in human lymphocytes. Canstatin has strongly inhibitory effect on growth and metastasis of mouse Lewis lung carcinoma.

BACKGROUNDAngiogenesis is essential for tumor's growth and metastasis. Canstatin, a newly found potent endogenous angiogenesis inhibitor, has drawn researcher's attention to its powerful biological activities on endothelial cells. The aim of this experiment is to explore the expression and effects of canstatin gene in lung cancer A549 cells and HUV-ECC cells.

METHODSExpression vector of pCMV- Script/Canstatin was transfected into A549 and ECC cells by electroporation, and the positive clone was screened by G418. Growth characteristics of the two cell lines were compared before and after transfection. Expression of canstatin protein in supernatant was examined by SDS-PAGE assay, and cell cycles of the two cell lines were analysed by flow cytometry.

RESULTSThe expression of canstatin gene was found in supernatant of the transfected A549 cells and ECC cells. The apoptotic rate in the transfected ECC cells (16.04%) was significantly increased compared with that of the naked plasmid control group (0.43%) and parental cell group (2.92%) (P < 0.01). The growth of the transfected ECC cells was significantly inhibited (P < 0.01). The apoptotic rate in the transfected A549 cells (0.19%) showed no marked difference from the naked plasmid control group (0.13%) and parental cell group (0.07%) (P > 0.05). No significant difference in cell growth was found among the transfected A549 cell, naked plasmid control and parental cell groups.

CONCLUSIONSThe results indicate that canstatin gene can express in lung cancer A549 cell line and HUV-ECC cell line, and it can specifically inhibit proliferation of endothelial cell and induce its apoptosis.

Objective:To explore the effect of artificial intelligence teaching-picture system in training the bone marrow cell morphological reading ability of clinical medical students.Methods:A total of 110 five-year undergraduate students were divided into experimental group (artificial intelligence picture teaching method) and control group (traditional teaching method) in the bone marrow cell morphology reading ability training. On the basis of multimedia teaching, the experimental group was given the teaching by using the bone marrow cell morphology picture storage and transmission system for retrieval, learning and computer adaptive test. Then objective evaluation of image recognition ability and questionnaire were used to compare the teaching effect.Results:The image recognition ability was significantly better in the experimental group than in the control group [(89.6±5.7) vs. (81.4±4.9), P<0.01]. Furthermore, the experimental group showed more obvious advantages in cell morphology recognition [(74.7±4.0) vs. (68.7±4.9)] and diagnosis of hematological diseases [(14.9±3.0) vs. (12.9±2.4)] than the control group (both P<0.01). Questionnaire survey showed that the students expressed their affirmation and support for the artificial intelligence teaching-picture system in the bone marrow cell morphological reading ability training. Conclusion:The application of artificial intelligence teaching-picture system can greatly improve the teaching effect, mobilize students' learning enthusiasm and expand learning resources, which is worthy of further promotion and application.

Objective:To investigate the pathological characteristics and the clinical significance of novel coronavirus (2019-nCoV)-infected pneumonia (termed by WHO as coronavirus disease 2019, COVID-19).Methods:Minimally invasive autopsies from lung, heart, kidney, spleen, bone marrow, liver, pancreas, stomach, intestine, thyroid and skin were performed on three patients died of novel coronavirus pneumonia in Chongqing, China. Hematoxylin and eosin staining (HE), transmission electron microcopy, and histochemical staining were performed to investigate the pathological changes of indicated organs or tissues. Immunohistochemical staining was conducted to evaluate the infiltration of immune cells as well as the expression of 2019-nCoV proteins. Real time PCR was carried out to detect the RNA of 2019-nCoV.Results:Various damages were observed in the alveolar structure, with minor serous exudation and fibrin exudation. Hyaline membrane formation was observed in some alveoli. The infiltrated immune cells in alveoli were majorly macrophages and monocytes. Moderate multinucleated giant cells, minimal lymphocytes, eosinophils and neutrophils were also observed. Most of infiltrated lymphocytes were CD4-positive T cells. Significant proliferation of type Ⅱ alveolar epithelia and focal desquamation of alveolar epithelia were also indicated. The blood vessels of alveolar septum were congested, edematous and widened, with modest infiltration of monocytes and lymphocytes. Hyaline thrombi were found in a minority of microvessels. Focal hemorrhage in lung tissue, organization of exudates in some alveolar cavities, and pulmonary interstitial fibrosis were observed. Part of the bronchial epithelia were exfoliated. Coronavirus particles in bronchial mucosal epithelia and type Ⅱ alveolar epithelia were observed under electron microscope. Immunohistochemical staining showed that part of the alveolar epithelia and macrophages were positive for 2019-nCoV antigen. Real time PCR analyses identified positive signals for 2019-nCoV nucleic acid. Decreased numbers of lymphocyte, cell degeneration and necrosis were observed in spleen. Furthermore, degeneration and necrosis of parenchymal cells, formation of hyaline thrombus in small vessels, and pathological changes of chronic diseases were observed in other organs and tissues, while no evidence of coronavirus infection was observed in these organs.Conclusions:The lungs from novel coronavirus pneumonia patients manifest significant pathological lesions, including the alveolar exudative inflammation and interstitial inflammation, alveolar epithelium proliferation and hyaline membrane formation. While the 2019-nCoV is mainly distributed in lung, the infection also involves in the damages of heart, vessels, liver, kidney and other organs. Further studies are warranted to investigate the mechanism underlying pathological changes of this disease.

The clinical research model based on evidence - based medicine (EBM) can effectively improve students' learning initiative, cultivate their abilities to obtain information and solve problems, and strengthen their scientific and innovative thinking in clinical research. Moreover, the EBM-based clinical research model can also help supervisors to update knowledge system and maintain strong clinical innovative thinking and research ability. The EBM - based clinical research model was applied in the cultivation of postgraduate students in hematology, and through topic selection, new technique application, ethical number acquisition, registration of clinical research number, case enrollment, and statistical analysis, postgraduates can master the methods and process of clinical research, which lays a solid foundation for future research.