BACKGROUND:The auditory ossicle chain reconstruction is stil an important method to treat conductive deafness. Although a great variety of materials have been applied, the blood supply of otosteon after the implantation is ignored. Moreover, there is no real bone formed.
OBJECTIVE:To observe the angiogenesis of vascular endothelial growth factor and col agen I modifiedβ-tricalcium phosphate porous scaffold which is implanted into the otocyst of guinea pig.
METHODS:Total y 60 guinea pigs were randomly divided into experimental group (vascular endothelial growth factor and col agen I modifiedβ-tricalcium phosphate porous scaffold), col agen I control group (col agen I modifiedβ-tricalcium phosphate porous scaffold) and blank control group (β-tricalcium phosphate porous scaffold). The guinea pigs were executed under anesthesia at weeks 1, 2, 3, 4 respectively. The surface of scaffolds was observed by scanning electron microscopy. The angiogenesis of scaffolds were observed by hematoxylin-eosin staining and CD34 immunohistochemistry staining, and then the microvascular density was counted. The osteogenesis of the scaffolds was observed by toluidine blue staining.
RESULTS AND CONCLUSION:Endothelial cel proliferation and lumen formation could be observed after 1 week in the experimental group, and the angiogenesis reach the peak after 3 weeks with traffic branches formedbetween micropores. In the other two groups, the lumen formed at 2 weeks but no traffic branches were visible. The sprouting of new blood vessels in the pores were observed more in the experimental group than the other two groups (P<0.05). The adherence and proliferation of cel s could be examined in the surface and pores of the scaffold by scanning electron microscope. After 4 weeks, the osteogenesis could be observed by toluidine blue staining, especial y in the experimental group. These findings suggest that the vascular endothelial growth factor and col agen I modifiedβ-tricalcium phosphate porous scaffold can realize an effective vascularization in the environment of guinea pigs’ middle ear. What’s more, the scaffold also can promote bone formation.

Objective To introduce and compare different trajectory analysis methods.Methods Simulation experiments were conducted to compare the effect and applicable conditions of different trajectory analysis methods under different scenarios.Dataset of SPRINT was analyzed using these methods.Results Growth mixture modeling(GMM)performed best in single trajectory analysis while group-based trajectory modeling(GBTM)and cluster analysis were able to analyze multivariate trajectory.Cluster analysis had strict requirements on follow-up data.Conclusion Each of these three methods has its own advantages,and the appropriate method can be selected according to the specific situation of the dataset.

In order to promote the connotation construction of the resident standardized training bases and improve the training quality, a tertiary hospital made key breakthroughs against the existing problems in the base under the guidance of national key training base standards in September 2020. Optimization and innovation were explored in terms of residential teaching supervision, performance appraisal system, regular teaching meeting, educational fund management, pilot project of full-time residential teaching secretaries, clinical skill center construction, cultivation of faculty development, and so on. These experiments have paved the way to high quality and sustainable development of residents standardized training. By the end of December 2021, the hospital had achieved significant progress in such aspects as residential teaching atmosphere, resident learning initiative, and training base branding. These achievements improved the quality of resident standardized training of the hospital in general, and provided a reference for promoting the high-quality development of residential training in China.

Due to the limited number of cases, conducting large-scale clinical trials for rare diseases is challenging. This review introduces several small sample statistical designs tailored for rare diseases, including crossover design, n-of-1 design, randomized placebo-phase design, randomized withdrawal design, group sequential design, and adaptive design. It discusses the advantages, disadvantages, and application scenarios of these designs. Additionally, it explores the benefits of Bayes decision-making in clinical trials for rare diseases. The aim is to provide a reference for designing and implementing small sample clinical trials for rare diseases.

Non-alcoholic fatty liver disease (NAFLD), as a metabolic disease, has shown a constant upward trend in prevalence among the people in recent years. In addition to changing lifestyles and conventional drug treatment, bariatric surgery, represented by Roux-en-Y gastric bypass surgery and sleeve gastrectomy, has gradually become one of the treatment options for NAFLD. However, the mechanism of bariatric surgery in treating NAFLD remains to be studied. The "multiple-hit theory", which has gradually been recognized in recent years, believes that NAFLD is formed by the combined effect of multiple mechanisms such as insulin resistance, bile acid metabolism pathway, and intestinal flora. Based on relevant literatures and clinical practices, the authors explore the relevant mechanisms of bariatric surgery for direct or indirect treatment of NAFLD.