Objective To investigate the chondrocyte proliferation and extracellular matrix biosynthesis of electrospun PCL scaffolds seeded with rabbit chondrocytes under flow perfusion culture in vitro.Methods Nonwoven PCL microfiber mats were fabricated,and contra-aperture cylindrical glass equipment as a perfusion bioreactor was designed and manufactured on our own.The experiment included peffusion culture group and static culture group.Primary chondrocytes were isolated from the knee joints of two-month-old New Zealand white rabbits and seeded into scaffolds.The scaffold-cell complexes were harvested at 3,7,and 14 days of culture for scanning electron micrograph (SEM) analysis,biochemical assay,real-time PCR and histology analysis.Results Electrospun PCL scaffolds were composed of microfibers with a diameter of 1.67±0.76 μm and pores with a diameter of 17.65±7.11 μm.SEM showed a better cell proliferation with typical morphology of chondrocytes under perfusion culture.At 7 days of culture,DNA content in perfusion culture group was higher than in static culture group.At 3,7 and 14 days of culture,compared with the static culture group,glycosaminoglycan (GAG) content and GAG/DNA ratio in perfusion culture group were higher,and the differences were statistically significant.At 14 days of culture,real-time PCR showed aggrecan and collagen type Ⅱ gene expression and collagen type Ⅱ to collagen type Ⅰ ratio were higher in perfusion culture group than in static culture group; HE and safranin O staining showed a significant cell proliferation,infiltration,as well as extracellular matrix biosynthesis in perfusion culture group.Conclusion Under flow perfusion culture,the electrospun PCL scaffolds seeded with rabbit chondrocytes can enhance chondrocyte proliferation and extracellular matrix biosynthesis,which is a promising method for cartilage tissue engineering.

With the development of business of manned spaceflight, the body damage of astronauts on the space en-vironment has received growing concern. Weight loss is the most important cause of various diseases, and the weightlessness muscle atrophy is one of urgent problems to be solved in aerospace medicine. Although there is no concept of weightlessness or weightlessness muscle atrophy in the theory of traditional Chinese medicine (TCM), TCM can grasp the pathogenesis of complex diseases, and provide important theoretical references for the prevention and management of weightlessness diseases, especially weightlessness muscle atrophy. In this paper, TCM Cognition of weightlessness and the pathogenesis of weightlessness muscle atrophy was studied by the sight of TCM theory of qi hoisting. The discussion was made from aspects of circulation of qi and blood, zang-fu function. This work is wished to be beneficial to apply the TCM theory in aerospace medicine.

Pancreatic leakage is most common among numerous complications after pancreaticoduodenectomy surgery.Predicting at early stage and taking preventive measures in time are of great importance to reducing the incidence of pancreatic leakage as well as its related complications.The article reviewed pancreatic leakage monitoring related reports worldwide in recent 10 years.It was found that some factors were useful for the prediction of pancreatic leakage including the drainage fluid amylase and leukocyte count on postoperative day 1 and 3,C-reactive protein on postoperative day 3,the combined detection of white blood cells and albumin on postoperative day 4,the serum urea nitrogen and the serum albumin on postoperative day 1 and 5-8 days,as well as the ratio of amylase level in abdominal drainage to abdominal drainage volume.

ObjectiveTo investigate the prevalence,antibiotic characteristics as well as molecular background of community-associated methicillin-sensitive Staphylococcus aureus (CA-MRSA) from patients with skin and sofi tissue infections from 4 different hospitals in Beijing.MethodsFive hundred and one patients were enrolled from 4 hospitals prospectively.Patients with skin and soft tissue infections and no risk factors for healthcare-associated acquisition were included.Sample from the infection sites were collected for culture.Case report form was filled out for each patient.Antibiotic susceptibility test and molecular analysis was performed for each Staphylococcus aureus isolate.ResultsTotally 164 Staphylococcus aureus isolates were cultured from the patients with skin and soft tissue infections.Of them 5 isolates were CA-MRSA.These 5 CA-MRSA isolates harbored SCCmec Ⅰ, SCCmec Ⅲ, SCCmec Ⅳ,SCCmec Ⅴ and untypable,respectively.CA-MRSA was highly resistant to β-lactamase,levofloxacin,erythromycin and clindamycin,but susceptible to vancomycin,teicoplanin,linezolid,daptomycin,and trimethoprim/sulfamethoxazole.Prevalence of PVL in community-associated methicillin sensitive Staphylococcus aureus(CA-MSSA) and CA-MRSA were 41.9％ and 2/5.Other toxins expressed similarly between them.Combined with multilocus sequence typing (MLST) and spa typing,the major clones of CA-MSSA were ST398-t034,ST7-t796,ST398-t571,ST1t127,and ST188-t189,while in CA-MRSA were ST239-t037-SCCmec Ⅰ,ST239-t632-SCCmecⅢ,ST59-t437-SCCmecV,ST8-t008-SCCmecⅣ,and ST6-t701-NT.ConclusionsThe low prevalence of CA-MRSA in Beijing and complexity of the genetic background in CA-MRSA were observed.Clone spread is not found among CA-MRSAisolates.CA-MRSAexhibithigher resistancecomparedwithmethicillinsensitive Staphylococcus aureus (MSSA).Rational drug use scheme is called in the clinical practice to prevent development of high level resistance.

Oral squamous cell carcinoma (OSCC) is a malignant tumor that seriously threatens human health. Its typical biological characteristics include strong local invasiveness, high lymph node metastasis rate, and high recurrence rate after treatment. Hepatocyte growth factor (HGF), cellular-mesenchymal to epithelial transition factor (c-Met), and the HGF/c-Met signaling pathway are involved in the regulation of the occurrence and development of OSCC. HGF and c-Met proteins are overexpressed in OSCC, and multiple studies have suggested that they are significantly associated with the malignant characteristics of tumors and poor prognosis. Furthermore, the abnormal activation of the HGF/c-Met signaling pathway (driven by HGF-dependent autocrine/paracrine or non-dependent mechanisms such as MET gene mutations, amplification, fusion, and protein overexpression) can synergistically promote tumor cell invasion, metastasis, and angiogenesis by activating downstream signaling pathways. However, HGF/c-Met can also mediate immune escape by promoting lactate secretion increase, inducing programmed death ligand 1 (PD-L1) expression upregulation, activating and expanding myeloid-derived suppressor cells, and promoting the proliferation of regulatory T cells (Tregs). In addition, the crosstalk between the HGF/c-Met signaling pathway and key pathways such as phosphatidylinositide 3-kinases (PI3K)/protein kinase B (AKT), epidermal growth factor receptor (EGFR), Janus kinase (JAK)/signal transducer and activator of transcription (STAT3), and non-coding RNAs can also promote tumor progression. Currently, three types of targeted drugs have been developed targeting the HGF/c-Met pathway: HGF monoclonal antibody, c-Met monoclonal antibody, and tyrosine kinase inhibitors. Some of these drugs have entered clinical trials. However, the emergence of drug resistance during treatment, especially the bidirectional compensatory activation of alternative signaling pathways such as EGFR, has become a major challenge in clinical practice. This article aims to provide an in-depth analysis of the mechanism of action of the HGF/c-Met pathway in OSCC and its interaction with other pathways, and to review the current research status of existing therapeutic drugs. The aim is to provide an important theoretical basis for developing more effective combined treatment strategies and achieving individualized precise treatment, ultimately improving the clinical prognosis and quality of life of patients.