BACKGROUND:The biological behavior of mesenchymal stem cells is influenced by the survival microenvironment.Pre-treatment of the microenvironment is an important means of regulating the function of mesenchymal stem cells. OBJECTIVE:To compare the differences in paracrine function of umbilical cord mesenchymal stem cells and adipose mesenchymal stem cells under oxidative stress and hypoxia,and to provide a theoretical basis for selecting appropriate pretreatment of mesenchymal stem cells to treat different diseases. METHODS:Umbilical cord mesenchymal stem cells and adipose mesenchymal stem cells were cultured by H2O2 or O2 oxygen,respectively,and cell morphology,proliferation,viability and paracrine factor expression were examined. RESULTS AND CONCLUSION:(1)The expression levels of brain-derived neurotrophic factor and transforming growth factor-β were higher in umbilical cord mesenchymal stem cells than in adipose mesenchymal stem cells under a normal culture environment,while the expressions of stromal cell-derived factor-1α and tumor necrosis factor stimulating factor-6 in the adipose mesenchymal stem cells were significantly higher than those in the umbilical cord mesenchymal stem cells.(2)There was no significant difference in the effect of low and moderate levels(≤100 μmol/L)of H2O2 on the viability of the two mesenchymal stem cells.However,increasing the H2O2 concentration from 50 μmol/L to 100 μmol/L resulted in a distinct increase in vascular endothelial growth factor expression in umbilical cord mesenchymal stem cells.The expression of basic fibroblast growth factor,vascular endothelial growth factor,stromal cell-derived factor-1α and interleukin-10 in adipose mesenchymal stem cells was greatly increased by increasing H2O2 concentration in this range.(3)1%O2 hypoxia promoted mesenchymal stem cell proliferation.After 24 hours of culture in 1%O2,gene expression levels were elevated in both mesenchymal stem cells,but the expression levels of vascular endothelial growth factor,interleukin-10 and tumor necrosis factor stimulating factor-6 were significantly higher in adipose mesenchymal stem cells than in umbilical cord mesenchymal stem cells.(4)It is concluded that hypoxia and oxidative stress preconditioning enhances the paracrine function of mesenchymal stem cells.However,mesenchymal stem cells respond differently to hypoxia and oxidative stress.Treating diseases can choose suitable mesenchymal stem cells for appropriate pretreatment to further enhance their therapeutic potential.

For wild natural medicine, unanticipated biodiversity as species or varieties with similar morphological characteristics and sympatric distribution may co-exist in a single batch of medical materials, which affects the efficacy and safety of clinical medication. DNA barcoding as an effective species identification tool is limited by its low sample throughput nature. In this study, combining DNA mini-barcode, DNA metabarcoding and species delimitation method, a novel biological sources consistency evaluation strategy was proposed, and high level of interspecific and intraspecific variations were observed and validated among 5376 Amynthas samples from 19 sampling points regarded as "Guang Dilong" and 25 batches of proprietary Chinese medicines. Besides Amynthas aspergillum as the authentic source, 8 other Molecular Operational Taxonomic Units (MOTUs) were elucidated. Significantly, even the subgroups within A. aspergillum revealed here differ significantly on chemical compositions and biological activity. Fortunately, this biodiversity could be controlled when the collection was limited to designated areas, as proved by 2796 "decoction pieces" samples. This batch biological identification method should be introduced as a novel concept regarding natural medicine quality control, and to offer guidelines for in-situ conservation and breeding bases construction of wild natural medicine.

Objective To investigate the changes and clinical significance of the expression of neutrophil gelatinase-associated li-pocalin(NGAL)and autophagy during different time of renal ischemia/reperfusion(I/R)injury in rats.Methods The rat renal I/R in-jury model was established,thirty male Wistar rats were divided by random number table method into sham operation group(Sham group)and I/R group,according to the different time of reperfusion after I/R injury,the I/R group was divided into 4subgroups:2h group,6h group,24h group,48h group.Blood,urine and renal tissue samples were collected at different time points,NGAL levels of blood and u-rineweredetectedbyenzyme-linkedimmunoadsordentassay(ELISA)method.Bloodureanitrogen(BU)and serum creatinine(SCr)were detected by automatic biochemical analyzer.Hematoxylin-eosin staining was used to detect the degree of histopathological injury and score the degree of injury.TdT-mediated dUTP nick end labeling(TUNEL)method was used to detect the apoptosis of renal tubular ep-ithelial cells;the expression of autophagy related genes LC3 and Beclin-1gene was detected by real-time quantitative polymerase chain reaction(RT-qPCR)method.Results The expression levels of NGAL in blood and urine were elevated in the 2h after I/R injury,and peaked at 6h of reperfusion,and showed a downward trend at 24h.BU and Scr values began to increase after the 6h reperfusion of I/R in-jury and peaked at 24h of reperfusion.TUNEL positive cells began to increase at 6h after I/R injury,the number of the highest was at 24h reperfusion of I/R injury.Hematoxylin-eosin staining showed that there were different degrees of swelling and necrosis of renal tubular epithelial tissue in all groups after I/R injury.The expression of LC3 and Beclin-1 gene began to increased after the 6h reperfusion of I/R injury and peaked at 24h of reperfusion.Conclusion The expression level of NGAL increased at the early stage of renal I/R injury in rats,which was earlier than the changes of BU and SCr levels,and could be used as a molecular indicator for early diagnosis of renal I/R injury.During the aggravation of renal I/R injury,the expression of NGAL was increased and autophagy was activated,which indica-ted that NGAL and autophagy played a certain role in the process of renal I/R injury.

In 2016, a national one million general population cohort project was set up in China for the first time in "Precision Medicine Research" Key Project, National Key Research and Development Program of China, which consists of general population cohorts in seven areas in China. As one of the seven major areas in China, northeastern China has unique climate and specific dietary patterns, and population aging is serious in this area. And the burden of chronic and non-communicable diseases ranks tops in China. Therefore, it is of great significance to establish a large general population cohort in northeastern China to explore the area specific exposure factors related to pathogenesis and prognosis of chronic and non-communicable diseases, develop new prevention strategies to reduce the burden of the diseases and improve the population health in northeastern China. In July 2018, the general population cohort study in northeastern China was launched, the study includes questionnaire survey, health examination and blood, urine and stool sample collection and detection in recruited participants. By now, the cohort has covered all age groups, and the baseline data of 115 414 persons have been collected. This paper summarizes the design and practice of the general population cohort study in northeastern China to provide reference for related research in China.

Carotid atherosclerosis (CAS) is closely associated with the decline of cognitive function in the elderly, which can lead to persistent or progressive cognitive function and neurological dysfunction. Vascular cognitive impairment (VCI) is considered to be an intervenable disease. Studies have shown that CAS is one of the main causes of VCI. Further study on the relationship between CAS and VCI will help to better prevention and treatment of VCI.

Neutrophil to lymphocyte ratio (NLR) can provide information of local or systemic inflammation and immune status. With the increasing attention to the role of inflammatory and immune factors in vascular cognitive impairment (VCI), it is very important to find new serum inflammatory markers for early identification and intervention of VCI. This article reviews the related research on NLR, VCI and their risk factors, expounds the role of inflammation in the pathogenesis of VCI, and provides help for the diagnosis and prevention of VCI.

Estrogen is an important hormone secreted by the female reproductive system. Its main function is associated with reproduction, growth and development. Studies have shown that estrogen has biological functions such as regulating vasoconstriction, antioxidant stress, anti-inflammatory and neuroprotection, and also affects brain structure and network. Studies have shown that estrogen is closely associated with the occurrence and development of white matter hyperintensities (WMHs). This article reviews the relationship between estrogen and menopausal hormone replacement therapy and WMHs, and their possible pathophysiological mechanisms.

Objective:To investigate the status quo and training needs of general practitioner (GP) job-transfer training program in Hebei Province.Methods:An online survey with self-designed questionnaire was conducted on May 2019 through WeChat among 165 trainees in the General Practice Training Center of Hebei Province. A total of 165 questionnaires were distributed and 149 were valid with an effective rate of 90.3%. The contents of the questionnaire included the basic information of the trainees, the evaluation of the current training, and the needs of the GPs′ job-transfer training.Results:Among 149 participants, there were 131 (87.9%)from the secondary hospitals or above, 146(98.0%)with bachelor′s degree or above, and 128 (85.9%)with intermediate or above professional titles. The survey showed that 72.0%(67/93)thought the main reasons affecting participation in the training were busy work load and insufficient personnel, the main problems of training were too short training duration(45.2%, 42/93), the not focused training contents(38.7%, 36/93) and lack of practice(37.6%, 35/93). In the 149 trainees, 136(91.3%) thought that the most important contents should be standardized diagnosis and treatment of common diseases; 104(69.8%), 118(79.2%), 115(77.2%) and 98(65.8%) considered that the knowledge of prevention and health-protection, first aid, latest progress and chronic disease management were needed for training; 110(73.8%)and 80(53.7%)thought the mastery of clinical practice and basic theory were needed. And 57.7% (86/149)of the trainees believed that research training was needed, and there was significant difference in the demand for research training among participants from different work units and with different professional titles (χ 2=15.371,10.625,all P<0.05). The accepted training methods were case study(53.7%, 81/149) and practical work(37.6%, 56/149). For training duration, 43.6% (65/149) thought it should not exceed 6 months and 56.4% (84/149) preferred more than 1 year; there was a significant difference in demanded training duration among trainees from different work units, with different education background and professional titles (χ 2=16.225,6.243,25.966, all P<0.05). Conclusion:We need a multi-channel and multi-level training model to establish a better job-transfer training system for general practitioners, in order to meet different training needs and to improve the effectiveness of the training.

Objective:To explore the effect of cabinet type water curtain exhaust hood applied to small sandblasting machine to prevent and control silicon dust, and put forward a new idea of dust ventilation protection facilities to effectively protect the occupational health of workers.Methods:From August to October 2018, the cabinet type water curtain exhaust hood of sandblasting room in a research institute was selected as the research object, and the methods of occupational health survey, on-site detection and physical simulation of air distribution were used to conduct on-site detection and smoke emission test on the local exhaust facilities, silica dust concentration, control wind speed and air distribution before and after the transformation line analysis and evaluation.Results:The air distribution simulation experiment showed that the air distribution of the cabinet type water curtain exhaust hood was reasonable and could effectively control the whole range of silica dust emission during the cleaning process. After modification, the capture velocity was increased from 0.01 m/s to 0.53 m/s, and the capture velocity was increased by 98.1%. The time weighted average allowable concentration ( CTWA) of silicon dust (total dust) during sand blasting, cabin opening and cleaning was reduced from 7.00 mg/m 3 to 0.50 mg/m 3. The CTWA of silica dust (exhalation dust) was decreased from 3.36 mg/m 3 to 0.27 mg/m 3, and the CTWA dust reduction rates of total dust and respirable dust were 92.9% and 92.0%, respectively. Conclusion:The combination of cabinet type exhaust hood and water curtain dedusting optimizes the combination mode of dust prevention and control. It has the advantages of high efficiency of dedusting and purification, energy saving and environmental protection, and can be popularized and used in enterprises of the same nature.

Objective:To explore the effect of cabinet type water curtain exhaust hood applied to small sandblasting machine to prevent and control silicon dust, and put forward a new idea of dust ventilation protection facilities to effectively protect the occupational health of workers.Methods:From August to October 2018, the cabinet type water curtain exhaust hood of sandblasting room in a research institute was selected as the research object, and the methods of occupational health survey, on-site detection and physical simulation of air distribution were used to conduct on-site detection and smoke emission test on the local exhaust facilities, silica dust concentration, control wind speed and air distribution before and after the transformation line analysis and evaluation.Results:The air distribution simulation experiment showed that the air distribution of the cabinet type water curtain exhaust hood was reasonable and could effectively control the whole range of silica dust emission during the cleaning process. After modification, the capture velocity was increased from 0.01 m/s to 0.53 m/s, and the capture velocity was increased by 98.1%. The time weighted average allowable concentration ( CTWA) of silicon dust (total dust) during sand blasting, cabin opening and cleaning was reduced from 7.00 mg/m 3 to 0.50 mg/m 3. The CTWA of silica dust (exhalation dust) was decreased from 3.36 mg/m 3 to 0.27 mg/m 3, and the CTWA dust reduction rates of total dust and respirable dust were 92.9% and 92.0%, respectively. Conclusion:The combination of cabinet type exhaust hood and water curtain dedusting optimizes the combination mode of dust prevention and control. It has the advantages of high efficiency of dedusting and purification, energy saving and environmental protection, and can be popularized and used in enterprises of the same nature.