Evaluation of COVID-19 Antigen Test Kit Assay Analytical and Clinical Performance / 中国医疗器械杂志

Objective To rapidly screen patients with novel coronavirus pneumonia (COVID-19) infection including asymptomatic ones. Method Established a rapid detection test kit, and evaluated analytical and clinical performance of it. Result The minimum limit of detection of the reagent was 9.75×102 TCID50/mL; there was no cross-reaction and interference in the high-concentration samples of 29 common respiratory pathogens tested. The diagnostic sensitivity of clinical samples was 98.56%, specificity was 99.00%, and the total coincidence rate was 98.85%; the consistency test Kappa value is 0.974 5. The stratified analysis of positive samples with different Ct values showed that the coincidence rate within each stratum was greater than 95%. Conclusion This COVID-19 antigen test kit with excellent detection performance, fast detection speed, and portable operation. It can be used as a supplementary method for existing nucleic acid detection methods for early screening of new coronavirus.

Establishment of kinetics digital model for hyaluronate lyase production based on fermentation optimization of Arthrobacter globiformis A152 / 生物工程学报

In order to produce hyaluronate lyase of high yield, we optimized the fermentation Arthrobacter globiformis A152 in quadruple fermentation of 5 L, and studied the kinetics of fermentation. Both the highest biomass and enzyme activity could be achieved when the rotation speed was 400 r/min and the ventilation volume was 3.5 L/min. In addition, digital models of cell growth, product synthesis and substrate consumption were built by equation of logistic, luedeking-piret, product synthesis and substrate consumption. Nonlinear fitting and estimation of optimal parameters were obtained by MATLAB. The model correlated well between prediction and experimental data, and reflected the change rules of cell growth, hyaluronidase synthesis and substrate consumption during the process of producing hyaluronate lyase. The establishment of fermentation kinetics digital models could provide basis for controlling and prediction of the production process.

Arterial spin labeling analysis of the cerebral blood flow in systemic lupus erythematosus patients / 医学研究生学报

Objective Neuropsychiatric systemic lupus erythematosus ( SLE) is a common complication of SLE, whose path-ogenesis is not yet clear but associated with the alteration of cerebral blood flow ( CBF) in some studies.This study was to investigate the CBF alteration in SLE patients without overt neuropsychiatric symptoms by arterial spin labeling ( ASL) MRI. Methods Twenty-eight SLE patients without overt neuropsychiatric symptoms and 30 age-and sex-matched healthy controls underwent conventional MRI and ASL examinations, and all received such neuropsychologic tests as number connecting test-A ( NCT-A ) , digit symbol test ( DST ) , self-rating anxiety scale ( SAS ) , and self-rating depression scale ( SDS) .Independent sample-t test was used to detect the mean CBF in the whole brain, gray matter, and white matter of the SLE patients and healthy controls.The voxel-wise CBF maps of the two groups of subjects were further analyzed with the SPM8 software to compare the regional CBF between the two groups, followed by evaluation of the correlation between the regional CBF values and clinical markers. Results In comparison with the healthy controls, the SLE pa-tients showed significantly reduced CBF in the gray matter (40.5 ±3.7 vs 37.3 ±6.5, P=0.028) and the whole brain (38.0 ±3.5 vs 35.1 ±6.1, P=0.032), especially in the supplementary motor area and the adjacent middle cingulate, anterior cingulate, left medial frontal gyrus, left inferior frontal gyrus, and left insula (P<0.05, FWE corrected).The NCT-A score was negatively correlated with the CBF values of the left medial frontal gyrus (r=-0.402, P=0.032) and left inferior frontal gyrus (r=-0.382, P=0.045) of the SLE patients. Conclusion ASL and MRI showed significantly reduced cerebral blood flow in the SLE patient without overt neu-ropsychiatric manifestations, which was correlated with the change of the patient's cognitive function.

Isolation, Purification and Structural Identification of Polysaccharide from Cordyceps Sinensis / 中国药师

Objective: To isolate and purify the polysaccharide from Cordyceps sinensis, and analyze its structure. Methods:Cordyceps sinensis was cultured by a liquid fermentation method. A water-extraction and alcohol-precipitation method was applied to ex-tract polysaccharide from Cordyceps sinensis fermentation liquor (EPS) and polysaccharide from Cordyceps sinensis mycelium (IPS). Sephadex gel chromatography was applied to isolate and purify the polysaccharide. The purity and relative molecular weight of the poly-saccharide were determined by a gel filtration method. The monosaccharide composition of the polysaccharide was identified by GC. The content of uronic acid was analyzed by sulfuric acid carbazole method. Results: The analysis results showed that the molecular weight of EPS was 78kDa. The content of polysaccharide and uronic acid was 94. 8% and 6. 0%, respectively. EPS was composed of mannose,glucose and galactose with the molar ratio of 4. 5∶8. 0∶1. 0. The molecular weight of IPS was 42kDa. The content of polysac-charide and uronic acid was 92. 5% and 4. 5%, respectively. IPS was composed of mannose,glucose and galactose with the molar ratio of 2. 8∶3. 0∶1. 0. Conclusion:Both polysaccharide EPS and IPS in Cordyceps sinensis are heteropolysaccharide.

Advances in algae tool enzymes: alginate lyases / 生物工程学报

Marine can be considered as a rather unexplored source of biological material. Production of algal oligosaccharides by using valuable enzymes from marine origin has become an important way to utilize marine resources. As one of algal tool enzymes, the use of alginate lyases has been focused mainly on development and application of alginate oligosaccharides with bioactive function in recent years. In this paper, we reviewed the research of alginate lyases over the past decade in several aspects, including their origin, diversity, substrate specification, mode of action, structure and catalysis mechanism, assay of enzyme activity, enzyme characterization, as well as our own experience on this subject. At the end of the review, the application prospects of alginate lyases are presented.

Preparation of Growth Hormone-Chitosan-Alginate Microcapsules and the Release Profile / 医学研究杂志

Objective To study the preparation and the in vitro and in vivo release profile of GH-Chitosan-Alginate microcapsules.Methods GH-Chitosan-Alginate microcapsules were prepared through impulsive electrostatic technique.The interrelated factors influencing the diameter and sphericity were studied through orthogonal experiments,and finally the statistic analysis made sure the optimum conditions to prepare microspheres.The morphology and size of the microcapsules were observed,and the content,encapsulation efficiency and recovery efficiency of the microcapsules were measured.Moreover,their in vitro and in vivo release experiments were carried out.Results The results showed that the diameter of needle was the most significant factor to the diameter of microspheres.The optimum conditions for the least diameter of microspheres were 450?m diameter of needle,2cm from needle tips to the gelation surfaee,1.5% alginate concentration,8ml/h speed of flowing-liquid and metal containers.The microcapsules had good sphericity morphology and distribution.The size of the microcapsules was in the range of 10-25?m with an average size of 47.93?m.The encapsulation efficiency and GH-load of the microcapsules were 94% and 11.24% respectively.The release kinetics of microcapsules was studied in false gastric and intestines juice.In false gastric juice,the GH of microcapsules was not released;in false intestines juice,it was released well,and TAM was completely released after about 12h.in vivo release profile made sure that the serum GH level of GH microcapsule group was at the highest value(98.59ng/ml) at 8h.The release profile was fitted well in both in vitro and in vivo conditions.Conclusion GH-Chitosan-Alginate Microcapsules have good morphology and sustained release effect.

Clinical application of helical CT 3D reconstruction for the dental orthopaedics / 中华放射学杂志

Objective To evaluate the clinical application of helical CT 3D reconstruction technique in the dental orthopaedics. Methods The helical CT was performed with 3.0 mm slice thickness and 1.0 pitch in 41 patients with dental orthopaedics. The 3D reconstructions, including maximum intensity projection (MIP), surface shaded display (SSD), and multiplanar reconstructions (MPR), were made for all the cases. Results Thirty-seven of the 41 patients showed malalignment, tilt, rotation, overlap of the teeth and the different space between the longitudinal axes of the teeth. Twenty-five cases of them have shown 36 buried teeth in all. The axial images covered all the information. SSD demonstrated the external contours and entire morphologies of the teeth and the mandible with the relationship of the teeth alignment and the mandible. MIP clearly manifested the full view and the longitudinal alignment of the teeth. Among the 36 buried teeth, there were 29 palatally and 7 labially presented teeth, and they were morphologically delineated on MIP through various angles. Conclusion The helical CT 3D reconstruction is a new technique to display the stereoscopic configuration of teeth. The combination of axial images and MIP, SSD, and MPR provides valuable anatomic and diagnostic information helpful for the surgeons to structure and determine the treatment protocol for the dental orthopaedics.

Analysis of the UV absorbing constituents of the metabolites from UV-B tolerance bacteria and study on its anti-ultraviolet mechanism / 中国海洋药物

Objective The anti-UV-B radiation mechanism of UV-B tolerance strain KFS-9 was studied from the profile of metabolites.Methods The compounds were separated by column chromatography and their structures were elucidated based on GC-MS,LC-TOF-MS,EI-MS and NMR analyses.Results Three unsaturated fatty acids(identified as 9-hexadecenoic acid,9,12-octadecadienoic acid and 11-octadecenoic acid) and 1,2-benzenedicarboxylic acid able to absorb ultraviolet were isolated from the petroleum ether extract of the fermentation liquid of Pantoea agglomerans KFS-9.Fraction(Ⅱ) was isolated from the ethyl acetate extract and was composed of 2,3-butanediol and a series of high unsaturated aroma compounds.Fraction(Ⅱ) had a wide absorption peak,and it could protect E.coli from UV-B damage in some sense.Conclusion Strain KFS-9 produced metabolites that were able to absorb UV to build a natural barrier and so improved the tolerance to UV radiation.The UV-B radiation protection test to the E.coli also showed fraction(Ⅱ) was not the only protector,and there definitely existedother materials and mechanism to protect the strain.

Metallo-?-lactamase Produced by Carbapenem-resistant Pseudomonas aeruginosa / 中华医院感染学杂志

OBJECTIVE To study the metallo-?-lactamases of 5 carbapenem resistant Pseudomonas aeruginosa isolates,which were recovered at 2006 in the Third People's Hospital of Yueqing. METHODS K-B method was used to determine the antimicrobial agents susceptibility in 5 isolates. The minimal inhibitive concentrations (MICs) of antimicrobial agents to these strains were determined by agar dilution method. Double disk synergy test was used to detect the metallo-?-lactamase. Molecular screening for blaIMP,blaVIM,and blaSPM was carried out using PCR method. The PCR product was sequenced. RESULTS One out of the 5 carbapenem resistant P. aeruginosa was positive for MBL double disk synergy test,and confirmed to contain blaVIM-2 gene. CONCLUSIONS A blaVIM-2-producing isolate of P. aeruginosa is identified. This carbapenem-resistant isolate is all multi-drug resistant.