BACKGROUND: Tissue-engineered skin plays an important role in the repair and reconstruction of large-area skin lesion. Little is known about the effects of Chinese medicine-loading tissue-engineered skin scaffold on cell adhesion and wound surface infection. OBJECTIVE: To screen the application concentration of shengji solution, which can promote tissue regeneration, using keratinocytes and fibroblasts, and to observe the effects of shengji solution-gelatin-chitosan drug-loading skin scaffold on cellular adhesion and biocompatibility. DESIGN, TIME AND SETTING: Taking keratinocytes and fibroblasts as subjects, the present randomized and controlled experiment was performed at the Laboratory of Cell Engineering, Orthopedic Institute, Tianjin Hospital between February and August 2005. MATERIALS: One healthy big-ear rabbit was included for harvesting skin seed cells. Shengji solution, Danggui (Radix Angelicee Sinensis) and Shengdi (rehmannia dride rhizome) extract (self-extracted, 1.5 g/mL), gelatin-chitosan scaffold and shengji solution-gelatin-chitosan scaffold were provided by Tianjin University, China. METHODS: Passage 3 keratinocytes and fibroblasts were harvested by dispase Ⅱ- trypsase- ethylenediamine tetraacetic acid(EDTA) digestion. The prepared cells were divided into 5 groups: control, shengji solution, Danggui, Shengdi, and epidermal growth factor (EGF). Common culture solution containing 0.1 volume fraction of fetal bovine serum, shengjisolution (5, 6, 8, and 12 g/L), Danggui extract (8 g/L), Shengdi extract (8 g/L), and EGF culture medium (10 μ g/L) were used in corresponding groups for cell culture. At 1, 3, 5, and 7 days, cellular proliferation was detected by methyl thiazolyl tetrazolium (MTT) assay. Keratinocytes and fibroblasts were cultured in different concentrations of shengji solution (50, 60, 80, and 120 g/L) and grouped according to different concentrations. At 7 and 14 days, cellular adhesion was observed by semi-quantitative method. At 4, 7, and 14 days, keratinocytes cultured by 60 and 80 g/L shengji solution were harvested for hematoxylin-eosin staining and subsequent scanning electron microscope observation. MAIN OUTCOME MEASURES: Effects of shengji solution on skin seed cell proliferation; effects of drug-loading scaffold on cellular adhesion; and cell-carrier biocompatibility. RESULTS: MIF detection results demonstrated that cells significantly proliferated after treatment of 5, 6, and 8 g/L shengji solution compared to the control group (P < 0.05). Obvious proliferation of passage 3 keratinocytes and fibroblasts was found on 60 and 80 g/L drug-loading scaffold. Keratinocytes on the drug-loading scaffold exhibited good cellular morphology and closely adhered to the scaffold. Shengji solution had no apparent toxic effects on cells. CONCLUSION: Shengji solution (60 and 80 g/L)-gelatin-chitosan scaffold can effectively promote the adhesion and proliferation of keratinocytes and fibroblasts.

Objective To investigate the role of spo0A gene in growth and sporulation of Clostridium difficile clinical isolates. Methods ClosTron gene knock-out system was used to knock out the spo0A gene of C. difficile strain C25. Bacterial growth curve was plotted by measuring D600 with spectrophotometer in different phases of bacterial growth. Malachite green staining technique was used to count the number of vegetative cells and spores under optical microscope. The sporulation rate was calculated. Results The spo0A mutant and its C25 parental strain showed similar patterns of growth. However, after knock-out of spo0A gene, an asporogenous phenotype was built, while the parental strain could produce spores as usual.Conclusions The spo0A gene plays a key role in sporulation but not growth of C. difficile strain.

Since December 2019, the corona virus disease 2019 (COVID-19) caused by the 2019 novel coronavirus (2019-nCoV) has been reported in Wuhan, Hubei Province. Almost 70% of patients susceptible to 2019-nCoV are over age of 50 years, with extremely large proportion of critical illness and death of the elderly patients. Meanwhile, the elderly patients are at high risk of osteoporotic fractures especially osteoporotic vertebral compression fractures (OVCF). During the prevention and control of COVID-19 epidemic, orthopedists are confronted with the following difficulties including how to screen and protect OVCF patients, how to accurately diagnose and assess the condition of OVCF patients with suspected or confirmed COVID-19, and how to develop reasonable treatment plans and comprehensive protective measures in emergency and outpatient clinics. In order to standardize the diagnosis and treatment of patients with OVCF diagnosed with COVID-19, the authors jointly develop this expert consensus. The consensus systematically recommends the standardized emergency and outpatient screening and confirmation procedures for OVCF patients with suspected or confirmed COVID-19 and protective measures for emergency and outpatient clinics. Moreover, the consensus describes the grading and classification of OVCF patients diagnosed with COVID-19 according to the severity of illness and recommends different treatment plans and corresponding protective measures based on the different types and epidemic prevention and control requirements.