Coronavirus Disease 2019 (COVID-19) is an infectious disease caused by 2019 novel Coronavirus (2019-nCoV). At present, the most used method to diagnose 2019-nCoV is nucleic acid test. Suspected cases underwent real-time fluorescent RT-PCR examination, and those who were 2019-nCoV nucleic acid positive were confirmed cases. However, in the process of nucleic acid test, factors such as specimen quality, specimen transportation and storage conditions, detection reagents and methods may cause false negative or false positive results. This article reviews the factors that may affect the results of 2019-nCoV nucleic acid test, and provides a basis for the diagnosis of suspected COVID-19 cases.

This article reviews the concept and research tools of social distancing, the current situation and influencing factors of social distancing in elderly diabetic patients, in order to provide a basis for the development of targeted intervention strategies for elderly diabetic patients, reduce the sense of social alienation in elderly diabetic patients, and promote their social participation and sense of meaning in life.

Objective:To compare the changes of serum calcium level before and after surgical resection in patients with primary hyperparathyroidism.Methods:Two hundred and seventy-one patients with primary hyperparathyroidism were enrolled from Dec 1992 to Dec 2020 in Beijing Jishuitan Hospital. Serum calcium concentrations were measured before operation, 20 min during surgery, then 2 weeks 1-6 months , 7-12 months and 1 year respectively after operation. The baseline data of postoperative serum calcium such as sex, age, other genetic endocrine diseases, osteopathia and urolithiasis were calculated. The generalized estimation equation was used to analyze the changes of serum calcium in different types of patients before and after operation.Results:The most common postoperative hypocalcemia occurred within 2 weeks, and it occurred frequently half a year after surgery. There was no significant difference in blood calcium between male patients ( t=0.875, P=1.000) and patients with bone lesions ( t=0.034, P=3.049) from 1 to 6 months after surgery and 2 weeks after surgery. Blood calcium level in patients aged 15-35 years old from 1 to 6 months ( t=0.239, P=1.000) , from 7 to 12 months ( t=1.380, P=0.935) and 2 weeks after surgery was not statistically different. The change of bone mineral density was correlated with the change of blood calcium after operation ( F=6.895, P=0.004). Conclusions:The incidence of hypocalcemia was the highest in patients with hyperparathyroidism 2 weeks after surgery, and the blood calcium level was stable within the normal range 1 year later. The blood calcium value of male patients was still at a lower level than that of female patients within six months after surgery. In patients with bone disease, the blood calcium value was lower and recovered slowly 2 weeks after surgery. The blood calcium value of patients aged 15-35 was at a low level within 1 year after surgery.

Objectiv:To evaluate ultrasound, radionuclide imaging and CT in preoperative localization diagnosis of primary hyperparathyroidism (PHPT).Method:A total of 170 PHPT patients admitted to the hospital between Jan 1992 and Dec 2020 were analyzed retrospectively. The preoperative localization diagnostic efficacy of ultrasonography, radionuclide and CT alone and in combination was compared in groups.Results:The overall sensitivity of ultrasound, radionuclide and CT were 82.13%,80.43% and 75.74%. For normal positioned parathyroid adenoma: as for sensitivity of location diagnosis, ultrasound (86.67%) was higher than radionuclide (81.82%, P<0.05) and CT (80.59%, P<0.05), ultrasound/CT parallel test (94.70%, P<0.05) was higher than ultrasound alone. For specificity of location diagnosis, radionuclide (97.78%) was higher than ultrasound (91.62%) and CT (93.39%), both ultrasound/radionuclide series tests (99.00%, P<0.001)and ultrasound/CT series tests (96.94%, P<0.001) were higher than ultrasound alone. In case of ectopic parathyroid adenoma and parathyroid hyperplasia: the sensitivity and specificity of radionuclide seemed higher than ultrasound and CT. Conclusions:Ultrasound is the first choice for preoperative location diagnosis of PHPT. Ultrasound combined with radionuclide or CT can significantly improve the diagnostic efficiency of parathyroid lesions.

Clinical data of a 33-year-old rheumatoid arthritis patient accompanied with pregnancy and lactation-associated osteoporosis(PLO) was retrospectively reviewed.The patient had two pregnancies within three years,and bone pain occurred during lactation of the second pregnancy after 2 months of delivery.Dual-energy X-ray (DEXA) showed decreased bone density,while thoracolumbar spine and pelvic X-ray film suggested osteoporosis.Her rheumatoid arthritis was stable and previous treatment did not include glucocorticoids.Other causes of metabolic bone diseases were excluded and the diagnosis of PLO was confirmed.The breastfeeding was stopped;calcium,active vitamin D,alendronate sodium were administrated,and the treatment was effective.Domestic and international literature from January 2000 to January 2019 was searched and no cases of PLO accompanied with rheumatoid arthritis were reported.There were only 100 cases of PLO retrieved in the literature,including 19 cases of PLO in China reported by four articles.It is suggested that PLO should be considered in RA patients presenting with arthragia during the lactation,in addition to relapse of disease.Awareness of PLO should be increased in physicians,especially rheumatologists,and anti-osteoporosis therapy is effective in patients with PLO.

Clustered regularly interspaced short palindromic repeats (CRISPR) are acquired immune system in bacteria and archaea. This system is used in site-directed gene editing. Recently, scientists discovered new CRISPR-associated (Cas) proteins, in which Cas12a-mediated gene editing can significantly reduce the off-target rate. In this article, we review CRISPR/Cas system's discovery of history, composition, classification, and working principle. The latest research progress of the CRISPR/Cas system, and its application in zebrafish are introduced.

Objective: To investigate the antimicrobial resistance and molecular epidemiology of foodborne Yersinia (Y.) enterocolitica in Pudong New District of Shanghai. Methods: Four kinds of raw food samples were collected in retail circulation sites in Pudong from 2012 to 2016. Cold enrichment method was used to isolate Y. enterocolitica and further detection of biotype, serotype, virulent genes, antimicrobial susceptibility of the isolates and pulsed field gel electrophoresis (PFGE) were conducted. Results: A total of 3 900 raw food samples were collected during this period, including poultry product (n=590), livestock product (n=1 074), aquatic product (n=1 488), vegetable (n=748), in which 111 (2.8%) were contaminated by Y. enterocolitica. The detection rates of Y. enterocolitica in poultry product samples (5.3%, 31/590) and livestock product samples (4.5%, 48/1 074) were higher than those in aquatic product samples (1.6%, 24/1 488) and vegetable samples (1.1%, 8/748). The predominant biotype was 1A (95.5%) and predominant serotype was O∶8 (42.3%). All the strains lacked ail, ystA, yadA and virF genes, which encoded pathogenic Y. enterocolitica. Seventy six (68.5%) strains harbored ystB gene, in which 35 (31.5%) belonged to 1A/O∶8/ystB pattern. Most strains were resistant to ampicillin (74.8%) and amoxicillin/clavulanic acid (70.3%), and non-sensitive rate to Cefoxitin was over 50.0%. No third generation cephalosporin or fluoroquinolone resistant strains were detected, but 38.7% (43/111) strains were multidrug resistant (MDR). Serotype O∶8 and O∶5 strains had 44 and 18 PFGE patterns, respectively. Conclusions The main foodborne exposure sources of Y. enterocolitica in raw food were poultry and livestock products in Pudong New District. 1A/O∶8/ystB was the predominant pattern with potential pathogenicity despite lacks of typical pathogenic virulent genes. The antimicrobial resistant rates of Y. enterocolitica were at a low level, but MDR strains still existed. Molecular types of the isolates showed highly genetic diversity.