Technical requirements for prevention and control of the COVID-19 in primary and secondary schools / 中国学校卫生

Abstract@#To scientifically guide the prevention and control of the COVID-19 in primary and secondary schools，this article proposes comprehensive and multi-link technical requirements in terms of organizational security and systems, personnel management and control, prevention and control of key areas, environmental cleaning and disinfection, emergency treatment, and return of teachers and students from overseas.

Constitutive display of Candida antarctica lipase B on the cell surface of Aspergillus niger and regulation of its fermentation / 生物工程学报

Displaying Candida antarctica lipase B (CALB) on the cell surface of Aspergillus niger is effectively applied for the industries of food, cosmetics, pharmaceutical and so on. Displaying CALB using induced promoter of glucoamylase on the cell surface of A. niger SH-1 has some problems such as inhibiting its expression under high concentration of glucose, mycelium cleavage and decreasing enzyme activity in the later period of fermentation process. Displaying CALB manipulated by constitutive promoter from glyceraldehyde-3-phosphate dehydrogenase instead of glucoamylase on the cell surface of A. niger SH-1, called AN-GpdA, could solve the above problems effectively. Furthermore, it can not only use glucose, but also xylose as a sole carbon source. Enzyme activity of AN-GpdA using xylose for fermentation reached 1 100.28 U/g of dry cell. We also used lignocellulose such as the hydrolysate of bagasse for fermentation with good performance. The result would provide a novel strategy for the utilization of bagasse.

Extent of Lung Involvement and Serum Cryptococcal Antigen Test in Non-Human Immunodeficiency Virus Adult Patients with Pulmonary Cryptococcosis / 中华医学杂志(英文版)

<p><b>Background</b>Serum cryptococcal antigen (CrAg) test is the most used noninvasive method to detect cryptococcal infection. However, false-negative CrAg test is not uncommon in clinical practice. Then, the aim of this study was to investigate the factors associated with false-negative CrAg test among non-human immunodeficiency virus (HIV) adult patients with pulmonary cryptococcosis and its clinical features.</p><p><b>Methods</b>One hundred and fourteen non-HIV adult patients with pulmonary cryptococcosis, proven by biopsy, were retrospectively reviewed. Finally, 85 patients were enrolled; 56 were CrAg positive (CrAg+ group) and 29 were negative (CrAg- group). It was a cross-sectional study. Then, baseline characteristics, underlying diseases, clinical symptoms, laboratory findings, and chest radiological findings were reviewed and analyzed. Chi-square test was used to analyze categorical variable. Odds ratio (OR) was used to measure correlation. Student's t- test was obtained to analyze continuous variable.</p><p><b>Results</b>No difference in baseline characteristics, underlying diseases, clinical symptoms, and laboratory findings were found between two groups (P > 0.05 in all). Nevertheless, diffuse extent lesion was 82.1% in CrAg+ group and 10.3% in CrAg- group (χ = 40.34, P < 0.001; OR = 39.87).</p><p><b>Conclusions</b>Among patients with limited pulmonary involvement, a negative serum CrAg does not preclude the diagnosis of pulmonary cryptococcosis. However, among patients with extensive pulmonary involvement, serum CrAg is a useful diagnostic tool for pulmonary cryptococcosis. Furthermore, we also noticed that the untypical and mild presentations with extensive pulmonary lesion might be the features of pulmonary cryptococcosis, which needs further investigation.</p>

Effects of Biofilm Formation on The Antimicrobial Susceptibility of Staphylococcus aureus

Staphylococcus aureus induces chronic infection in form of biofilm that exists in the host cells and arthroplastic prosthesis surface. In this study, the biofilm formation ability of S. aureus clinically isolated from bacteremia patients, biofilm processing and relationship of resistance to antibiotics, and difference of biofilm formation ability on different prosthetic material surfaces were studied. All of them formed biofilm and especially 6 strains of S. aureus had high ability of biofilm formation. In addition, it was found that some strains with higher biofilm formation ability make more higher polysaccharide layer production. When S. aureus ATCC 25923 forms biofilm, minimal bactericidal concentration (MBC) of biofilm bacteria is more increased than that of the planktonic state bacteria about one thousand folds. Especially, after 6 hours from starting on biofilm formation, the resistance to antibiotics was increased by more than 256 microgram/ml of MBC to every antibiotics and after 8 hours prominent increase (more than 4096 microgram/ml) was noted. Biofilm formation after bacterial adherence to plastic cover-slip was increased with time-dependent manner. Microcolonies were formed after 5 hours from a point that bacteria adhere to plastic cover-slip surface and after 6 hours biofilm was diffusely formed on entire surface, and then after 8 hours very thick biofilm was formed. Thicker biofilm was found on cobalt-chromium than titanium surface. These results suggest that titanium alloy materials are better than cobalt-chromium to minimize S. aureus biofilm formation on the arthroplastic material surface. Also, when microcolonies are formed after adherence of S. aureus to the arthroplastic material surface, resistance to antibiotics is starting.

Study of expression of CD138 and heparinase in hepatocellular carcinoma by tissue microarray / 中华病理学杂志

<p><b>OBJECTIVE</b>To study the expression of CD138 and heparinase in hepatocellular carcinoma (HCC) and its relationship with tumor development, progression, metastasis and recurrence.</p><p><b>METHODS</b>Tissue microarray and immunohistochemical study (EnVision method) for CD138 and heparinase was performed on tissue microarray which consisted of 197 cases of HCC, including adjacent non-neoplastic liver tissues, and 66 cases of HCC metastases.</p><p><b>RESULTS</b>The rates of CD138 expression in HCC and adjacent non-neoplastic liver tissues were 48.7% (96/197) and 65.0% (128/197, P < 0.05) respectively. In early-stage and late-stage tumors, the expression rates were 61.7% (29/47) and 44.7% (67/150, P < 0.05) respectively. The rate in patients with metastasis was 33.3% (22/66), as compared with 53.6% (45/84, P < 0.05) in patients without metastasis. In patients with tumor recurrence occurring within or after 1 post-operative year, the expression rates were 23.3% (7/30) and 61.1% (11/18, P < 0.05) respectively. On the other hand, the rates of expression of heparinase in HCC and adjacent non-neoplastic liver tissues were 35.5% (70/197) and 12.7% (25/197, P < 0.05) respectively. In early-stage and late-stage tumors, the expression rates were 29.8% (14/47) and 37.3% (56/150, P > 0.05) respectively. The rate in patients with metastasis was 48.5% (32/66), as compared with 28.6% (24/84, P < 0.05) in patients without metastasis. In patients with tumor recurrence occurring within or after 1 post-operative year, the expression rates were 50.0% (15/30) and 44.4% (8/18, P > 0.05) respectively. In the 66 cases of metastatic HCC studied, the expression rate of CD138 was lower in the heparinase-positive subgroup (P < 0.05).</p><p><b>CONCLUSIONS</b>Loss of CD138 expression is related to HCC development, progression, metastasis and recurrence. Overexpression of heparinase, when coupled with loss of CD138 expression, may take part in tumor metastasis of HCC.</p>