Objective:To investigate the expression and clinical significance of growth differentiation factor 15 (GDF-15) in papillary thyroid carcinoma (PTC).Methods:The tumor tissues and metastatic lymph node tissues of 3 PTC patients who underwent radical surgery of thyroid cancer in the First Hospital of Hunan University of Chinese Medicine from January to February 2019 were collected, and the differential expressed genes were screened by high-throughput sequencing; 20 cases of primary tumor tissues and metastatic lymph node tissues were collected to verify the sequencing results. Another 20 cases of primary PTC tissues and adjacent tissues (>2 cm away from the tumor edge) were collected to verify the expression of target genes in tumor tissues and adjacent tissues. Sixty-four pathological specimens of PTC patients who underwent radical surgery of thyroid cancer in the First Hospital of Hunan University of Chinese Medicine from January to December 2014 were collected, of which 31 patients had lymph node metastasis. The real-time fluorescent quantitative polymerase chain reaction (qRT-PCR) was used to detect the expression of GDF-15 and verify the sequencing results; immunohistochemistry was used to detect the expression of GDF-15 protein in the primary PTC tissues, adjacent tissues and metastatic lymph node tissues. According to the expression of GDF-15 protein in the primary tumor tissues of PTC patients, the patients were divided into high-expression group (35 cases) and low-expression group (29 cases), and the relationship between GDF-15 expression level and clinicopathological characteristics of patients was analyzed; Kaplan-Meier method was used to analyze the 5-year tumor-free survival rate of the two groups.Results:The mRNA high-throughput sequencing results of 3 cases of PTC primary and metastatic tissues showed that the top 10 differential expressed genes were CDH2, CDF15, DKK1, GLIPR1, PCDH7, ID3, FBN1, MYPN, UBASH3B and CCDC80. The expression of GDF-15 mRNA in 20 cases of PTC primary tumor tissues and adjacent tissues were 4.1±0.5 and 2.8±0.3, and the difference was statistically significant ( t = 2.220, P = 0.032). The expression of GDF-15 mRNA in another 20 cases of PTC primary tumor tissues and metastatic lymph node tissues were 3.1±0.4 and 5.8±0.7, and the difference was statistically significant ( t = 3.556, P = 0.001). The results of immunohistochemistry showed that GDF-15 had the immunohistochemical scores of (4.0±0.3) points, (6.1±0.3) points and (9.0±0.4) points in PTC adjacent tissues, primary tumor tissues and metastasis tissues. The expressions of GDF-15 protein between PTC primary tumor tissues and adjacent tissues, metastatic tissues and adjacent tissues, and metastatic tissues and primary tumor tissues were significantly different (all P < 0.01). The differences in composition ratios of tumor long-axis diameter, tumor T stage and N stage between GDF-15 high-expression group and low-expression group were statistically significant (all P<0.05). The 5-year tumor-free survival rates in GDF-15 high-expression group and low-expression group were 60% and 83%, and the difference was statistically significant ( P = 0.033). Conclusions:The expressions of GDF-15 in PTC adjacent tissues, tumor tissues and metastatic lymph node tissues gradually increase, and its expression level is related to tumor progression, recurrence and metastasis. It can be used as a potential clinical prognostic warning molecule and therapeutic target.

Objective To investigate the effects of a novel scientific research practice model on medical undergraduates'!cognition and behavior. Method Totally, 60 medical undergraduates took part in the research. All of them accepted scientific research training by using improved tutorial system + team-based learning (TBL) combat training models. Before and after training, students completed the same ques-tionnaires respectively. The content included the purpose of participating in scientific research activities, the interest of scientific research, and the confidence and satisfaction of publishing scientific research papers, etc.. SPSS 16.0 was used to conduct non parametric Mann-Whitney test or Wilcoxon non parametric test to the pre and post survey data. Results Fifty-seven students (95.0%) were satisfied with the novel teaching model. Before and after training, the liking scores for scientific research practice rose from 1.12 (95%CI=0.65 to 1.59) to 5.87 (95%CI=5.34 to 6.39), P=0.001. Fifty-three students (88.3%) proactively participated in research work after training compared with 21 students (35.0%) before training, P=0.000. More students had confidence in publishing academic papers on Chinese core journals or Science Citation Index journals after training (P=0.000, P=0.003 respectively). 57 students (95%) said they were very satisfied or satisfied with the training of scientific research and practice. Conclusion Improved tutorial system+TBL research combat training model can stimulate students'!interest in scientific research and make them have more pos-itive cognition and behavior on scientific research work.

Consecutively hospitalized patients with confirmed coronavirus disease 2019 (COVID-19) in Wuhan, China were retrospectively enrolled from January 2020 to March 2020 to investigate the association between the use of renin-angiotensin system inhibitor (RAS-I) and the outcome of this disease. Associations between the use of RAS-I (angiotensin-converting enzyme inhibitor (ACEI) or angiotensin receptor blocker (ARB)), ACEI, and ARB and in-hospital mortality were analyzed using multivariate Cox proportional hazards regression models in overall and subgroup of hypertension status. A total of 2771 patients with COVID-19 were included, with moderate and severe cases accounting for 45.0% and 36.5%, respectively. A total of 195 (7.0%) patients died. RAS-I (hazard ratio (HR)= 0.499, 95% confidence interval (CI) 0.325-0.767) and ARB (HR = 0.410, 95% CI 0.240-0.700) use was associated with a reduced risk of all-cause mortality among patients with COVID-19. For patients with hypertension, RAS-I and ARB applications were also associated with a reduced risk of mortality with HR of 0.352 (95% CI 0.162-0.764) and 0.279 (95% CI 0.115-0.677), respectively. RAS-I exhibited protective effects on the survival outcome of COVID-19. ARB use was associated with a reduced risk of all-cause mortality among patients with COVID-19.
Angiotensin Receptor Antagonists/therapeutic use* ; Angiotensin-Converting Enzyme Inhibitors/therapeutic use* ; COVID-19 ; Humans ; Hypertension/drug therapy* ; Renin-Angiotensin System ; Retrospective Studies