The marrow stromal osteoblasts from New Zealand rabbits were seeded on coral treated with L-polylysine, fibronectin and culture medium only, then the cells/coral composites were cultured in vitro. The cells/coral composites were observed for the process of cells growth and matrix formation at 7, 14 and 21 days after culture. With the aid of electron microscope,it was demonstrated that on the surface of the coral holes,which was treated with fibronectin, there were more adhering osteoblasts and matrix formation than those treated with both L-polylysine and culture medium after 7 and 14 days.Cell count in coral blocks was determined by doing a fluorimetric DNA assay. Although the samples treated with L-polylysine demonstrated higher cell count than the coral treated with culture medium after 7 days, there was no statistically difference between the two after 14, 21 days. At each time point, the samples treated with fibronectin showed higher cell count and alkaline phosphatase activity than the orals otherwise treated, and the cell count also increased with culture time. The study suggests that fibronectin has a significant effect on promoting the adhesion and proliferation of osteoblasts on the surface of coral.

Clinical work is the core of a hospital. The level of the clinical work and scientific research are the major indexes for the evaluation of a hospital or a clinician. However, there seems contradiction between the clinical work and scientific research. For hospital administration and clinicians, it is important to adopt clinical work as the center, and conduct research around the clinical practice, which will facilitate the transition from the scientific research to clinical application. Eventually the clinical work will improve and medical science will develop.

Based on the development of ethics of laboratory animal in our and foreign countries and the related problems in our country, the necessity and feasibility of construction of the ethics censorship sys-tem about the laboratory animal were discussed and some adviees were raised to promote administration of la-boratory animal.

Three forms of the major surface antigen (SAG1)of Toxoplasma gondii, that is the membrane form, the secrete form and the intracellular form, were constructed and used to immunize BALB/c mice. The humoral response in the mice immunized with the membrane form and the secrete form of SAG1 appeared earlier and stronger than those mice immunized with the intracellular form. Result from the challenging infection demonstrated that the protection in the mice immunized with the membrane and the secrete forms was also stronger than in the mice immunized with the intracellular form. We suggest that the immune efficiency of the three forms of SAG1 in the mouse model is different.

In this article, the authors expounded the necessary and problems of animal experiment post-ap-proval monitoring ( PAM) , which included who should do PAM, how to do PAM, and what the PAM can do. The authors also exposed the following suggestion: formulating the detailed rules, regulations and SOP, strengthening the training of PAM team member and animal experiment personnel, and monitoring the whole process of animal protocol review using the software.

Objective: To evaluate whether hemodialysis before percutaneous renal biopsy (PRB) reduces the risk of bleeding complications in patients with acute kidney injury (AKI). Methods: This study was a cohort observational study. Patients who were diagnosed as AKI and received PRB in Nanfang Hospital of Southern Medical University from January 2015 to December 2018 were included in the study. Patients were divided into preoperative dialysis group and preoperative non-dialysis group according to whether PRB patients received hemodialysis treatment. According to whether perirenal hematoma occurred after the operation, the patients were divided into the groups with and without the perirenal hematoma. The baseline clinical data of AKI stage, hemoglobin, coagulation function and renal pathological changes before PRB, and perirenal hemorrhage complications after operation, including the size of perirenal hematoma within 24 hours, gross hematuria, low back pain, decreased hemoglobin value and interventional treatment (such as interventional surgery, blood transfusion, etc) in the two groups were compared. The logistic regression model was used to analyze the risk factors of perirenal hematoma after PRB. Results: Ninety patients with AKI were enrolled in this study, including 41 in the preoperative dialysis group and 49 in the preoperative non-dialysis group. The proportion of patients AKI with stage 2-3 in the preoperative dialysis group was significantly higher than that in preoperative non-dialysis group (100.0% vs 75.5%, P<0.001). There were no significant differences in coagulation function indexes and platelet counts between the two groups. Renal ultrasound within 24 hours after PRB showed that there were no significant differences in the incidence of postoperative perirenal hematoma (56.1% vs 63.3%, P=0.489), the incidence of postoperative perirenal large size hematoma (≥5 cm, 26.1% vs 22.6%, P=0.766), and the magnitude of the decrease in hemoglobin (3.7% vs 1.2%, P=0.505) between the preoperative dialysis group and the preoperative non-dialysis group. No blood transfusion, arteriovenous fistula, renal vascular intervention or surgery, and no hospital death occurred in the two groups. The renal pathological manifestations of the patients with and without perirenal hematoma were mainly acute tubular necrosis (ATN) and there were no significant differences between the patients with and without perirenal hematoma in indicators such as age, gender, body mass index, diabetes percentage, hypertension percentage, AKI staging, preoperative dialysis or not, serum creatinine, blood urea nitrogen, hemoglobin, platelet count and renal pathological types. After adjusting for indicators such as preoperative AKI stage and renal pathological changes, logistic regression analysis results showed that perirenal after PRB was not independently correlated with preoperative dialysis (β=0.568, P=0.241); Multivariate logistic regression analysis resluts showed that hematoma (≥5 cm) after PRB was also not independently correlated with preoperative dialysis (β=0.967, P=0.958). Conclusions Preoperative hemodialysis does not reduce the risk of bleeding complications after PRB in patients with AKI. The role of preoperative hemodialysis in reducing the risk of bleeding complications after PRB needs further study and verification.

OBJECTIVETo develop a hydroponic Nicotiana cultivation system for rapid and high-yield transient expression of recombinant proteins under laboratory conditions.

METHODSTo establish the hydroponic cultivation system, several parameters were examined to define the optimal conditions for the expression of recombinant proteins in plants. We used the green fluorescent protein (GFP) and the geminiviral plant transient expression vector as the model protein/expression vector. We examined the impact of Nicotiana species, the density and time of Agrobacterium infiltration, and the post-infiltration growth period on the accumulation of GFP. The expression levels of GFP in Nicotiana leaves were then examined by Western blotting and ELISA.

RESULTSOur data indicated that a hydroponic Nicotiana cultivation system with a light intensity of 9000 LX/layer, a light cycle of 16 h day/8 h night, a temperature regime of 28 degrees celsius; day/21 degrees celsius; night, and a relative humidity of 80% could support the optimal plant growth and protein expression. After agroinfiltration with pBYGFPDsRed.R/LBA4404, high levels of GFP expression were observed in both N. benthamiana and N. tobaccum (cv. Yuyan No.5) plants cultured with this hydroponic cultivation system. An optimal GFP expression was achieved in both Nicotiana species leaves 4 days after infiltration by Agrobacterium with an OD(600) of 0.8. At a given time point, the average biomass of N. tobaccum (cv. Yuyan No.5) was significantly higher than that of N. benthamiana. The leaves from 6-week-old N. benthamiana plants and 5-week-old N. tobaccum (cv. Yuyan No.5) plants could be the optimal material for agroinfiltration.

CONCLUSIONWe have established a hydroponic cultivation system that allows robust growth of N. benthamiana and N. tobaccum (cv. Yuyan No.5) plants and the optimal GFP expression in the artificial climate box.

Gene Expression Regulation, Plant ; Genetic Vectors ; Green Fluorescent Proteins ; biosynthesis ; genetics ; Hydroponics ; methods ; Plants, Genetically Modified ; genetics ; Recombinant Proteins ; biosynthesis ; genetics ; Tobacco ; genetics ; growth & development

Objective:To explore the association between resting heart rate(RHR) and all-cause mortality among the Chinese oldest-old aged more than 80.Methods:Using a total of seven surveys or follow-ups data (1998, 2000, 2002, 2005, 2008, 2011 and 2014) from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). A total of 17 886 elderly over 80 years old were selected as subjects, their resting heart rate were measured though baseline survey and the survival outcome and death time of the subjects were followed up. The subjects were divided into 6 groups according to their resting heart rate. Cox regression model was used to estimate the effect of resting heart rate on mortality risk. The interaction of age, gender and resting heart rate was also analyzed by likelihood ratio test.Results:The age of subjects M( P25, P75) was 92 (86, 100) years old, including 10 531 females (58.9%) and there were 13 598 participants died, the mortality rate was 195.5 per 1 000 person-years. Multivariate Cox regression analysis showed that compared to the control group (60-69 pbm/min), the hazard ratio of the elderly are 1.06 (95% CI: 1.02, 1.11), 1.09 (95% CI: 1.04, 1.15), 1.23 (95% CI: 1.14, 1.34), 1.25 (95% CI: 1.08, 1.44) in the group of RHR between 70-79, 80-89, 90-99 and ≥100 pbm/min and Pvalues are all less than 0.05. Likelihood ratio test showed that RHR and age had an interaction effect. ( P for interaction=0.011). Conclusion:The risk of all-cause death increased with the increase of resting heart rate and this relationship was stronger between the 80-89 years old people.

Objective:To explore the association between resting heart rate(RHR) and all-cause mortality among the Chinese oldest-old aged more than 80.Methods:Using a total of seven surveys or follow-ups data (1998, 2000, 2002, 2005, 2008, 2011 and 2014) from the Chinese Longitudinal Healthy Longevity Survey (CLHLS). A total of 17 886 elderly over 80 years old were selected as subjects, their resting heart rate were measured though baseline survey and the survival outcome and death time of the subjects were followed up. The subjects were divided into 6 groups according to their resting heart rate. Cox regression model was used to estimate the effect of resting heart rate on mortality risk. The interaction of age, gender and resting heart rate was also analyzed by likelihood ratio test.Results:The age of subjects M( P25, P75) was 92 (86, 100) years old, including 10 531 females (58.9%) and there were 13 598 participants died, the mortality rate was 195.5 per 1 000 person-years. Multivariate Cox regression analysis showed that compared to the control group (60-69 pbm/min), the hazard ratio of the elderly are 1.06 (95% CI: 1.02, 1.11), 1.09 (95% CI: 1.04, 1.15), 1.23 (95% CI: 1.14, 1.34), 1.25 (95% CI: 1.08, 1.44) in the group of RHR between 70-79, 80-89, 90-99 and ≥100 pbm/min and Pvalues are all less than 0.05. Likelihood ratio test showed that RHR and age had an interaction effect. ( P for interaction=0.011). Conclusion:The risk of all-cause death increased with the increase of resting heart rate and this relationship was stronger between the 80-89 years old people.

Objective:To analyze the sensitivity and specificity of SARS-CoV-2 nucleic acid testing in 20 348 close contacts of COVID-19 cases in different prevention and control stages in Guangzhou and to provide scientific evidence for optimizing epidemic response strategies.Methods:A total of 20 348 close contacts of COVID-19 cases in Guangzhou were traced between February 21 and September 22,2020. All the close contacts were tested for the nucleic acid of SARS-CoV-2. The sensitivity and specificity of nucleic acid testing and diagnosis in the different prevention and control stages were compared.Results:In 20 348 close contacts, 12 462 were males (61.24%), the median ( P 25, P 75) of age of them was 31.0 years (23.0,43.0), the median number ( P 25, P 75) of nucleic acid testing for them was 2.0 (1.0,3.0), and the median ( P 25, P 75) of their quarantine days was 12.0 (8.0,13.0) days, respectively. A total of 256 COVID-19 cases were confirmed in the close contacts after seven nucleic acid tests. In the 1 st, 2 nd, 3 rd and 7 th nucleic acid testing, the sensitivity and specificity were 69.14% and 99.99% (177 cases confirmed), 89.84% and 99.99% (230 cases confirmed), 97.27% and 99.99% (249 cases confirmed), and 100.00% and 99.98%, respectively. In the three stages of COVID-19 prevention and control in China: domestic case stage, imported case stage, and imported case associated local epidemic stage, the sensitivity of the 1 st nucleic acid testing was 70.68%, 68.00% and 67.35%, and the specificity was 99.98%, 100.00% and 100.00%, respectively. Conclusions:The sensitivity of nucleic acid testing in the close contacts at the different stages were consistent with slight decrease, which might be related to the increased proportion of asymptomatic infections in the late stage of epidemic prevention and control with COVID-19 in Guangzhou. It is suggested to give three nucleic acid tests to improve the sensitivity and reduce false negative risk.