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Objective:To investigate the effect of virus inactivation on weak positive result of 2019 novel coronavirus(2019-nCoV) nucleic acid test.Methods:A retrospective study was conducted on the nasopharyngeal swabs of three patients with positive PCR nucleic acid test for 2019-nCoV at different concentrations in the Second affiliated Hospital of Zhejiang University Medical College from January to February 2020.The virus in nasopharyngeal swab specimens were inactivated by water bath at 56 ℃ for 30 min, dry bath at 56 ℃ for 60 min and dry bath at 60 ℃ for 30 min respectively. After treatment, these samples RNA were extracted and then detected by three new commercial quantitative real-time polymerase chain reaction reagent kits for 2019-nCoV.Cycle threshold (Ct) value was used to evaluate the effect of virus inactivation on nucleic acid detection of 2019-nCoV.Results:There was no significant difference between the groups before and after inactivation. Ct values of ORF1ab gene before inactivation were 23.28±0.28, 25.25±0.25, 28.93±0.44, 32.06±0.47, 35.20±0.38, 32.89±0.38, 36.24±0.23, 33.30±0.46, and those after inactivation were, group 1:23.60±0.20, 27.29±0.30, 31.83±0.51, 37.41±0.46, group 2: 24.25±0.34, 27.18±0.42, 31.84±0.61, 34.99±1.01, 34.89±0.45,group 3: 23.37±0.17, 26.89±0.52, 32.05±0.50.Ct value of N gene before inactivation were 24.38±0.09, 26.64±0.11, 30.35±0.12, 33.29±0.33, 36.93±0.11, 34.50±0.12, 35.63±0.12, those after inactivation were, group 1: 24.66±0.11, 28.52±0.14, 32.71±0.14, 37.00±0.13;group 2: 25.41±0.10, 28.79±0.15, 33.29±0.28; group 3: 23.37±0.11, 28.68±0.11, 33.54±0.13, 37.18±0.23(ORF1ab gene: t=-1.416; N gene: t=-1.379, P>0.05). There was no significant difference among the three inactivation groups, the specific Ct values are shown above(ORF1ab gene: t=-0.460; N gene: t=-0.132, P>0.05). However, the Ct values of the inactivated groups (1,2,3) and the non-inactivated group at different dilution times were different (10 ×:Ct value of ORF1ab was 25.25±0.25 in the non-inactivated group, and 27.29±0.30, 27.18±0.42 and 26.89±0.52 in the inactivated group1,2 and 3, t(ORF1ab)=-7.327, P<0.01.Ct value of N gene in the non-inactivated group was26.64±0.11, those in inactivated group 1, 2 and 3 were 28.52±0.14, 28.79±0.15 and 28.68±0.11, respectively, t (N)=-19.340, P<0.01. 100 ×:Ct value of ORF1ab was 28.93±0.44 in the non-inactivated group, and 31.83±0.51,31.84±0.61 and 32.05±0.50 in the inactivated group1,2 and 3, t (ORF1ab)=-9.462, P<0.01. Ct value of N gene in the non-inactivated group was 30.35±0.12, those in the inactivated group 1, 2 and 3 were 32.71±0.14, 33.29±0.28 and 33.54±0.13, respectively, t (N)=-18.583, P<0.01. The positive detection rate of the non-inactivated group (7/11, 8/11, 5/11) was significantly different from that of the inactivated group (inactivated group 1:4/11, 4/11, 3/11, inactivated group 2:3/11, 3/11, 3/11, and inactivated group 3:3/11, 3/11, 2/11) ( Z=-2.670, P<0.01). There were no significant difference among the inactivated groups(inactivated group 1:4/11, 4/11, 3/11, inactivated group 2:3/11, 3/11, 3/11, inactivated group 3:3/11, 3/11, 2/11) ( Z=4.413, P>0.05) and among the three reagents(reagent 1:7/11, 4/11, 3/11, 3/11, reagent 2:8/11, 4/11, 3/11, 3/11, reagent 3:5/11, 3/11, 3/11, 2/11)(χ 2=1.199, P>0.05). Conclusion:The virus inactivation can degrade the nucleic acid of the 2019-nCoV, resulting in the decrease of the Ct value and the false negative results of the low-concentration specimens.
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Objective To analyze the prevalence of influenza A (H3N2) virus in Hangzhou be-tween 2012 and 2017 and to investigate the genetic variations in hemagglutinin ( HA) and neuraminidase ( NA) . -ethods Throat swab samples were collected for viral isolation from 12185 patients with suspected influenza in Hangzhou area from January 2012 to December 2017. Influenza virus subtypes were identified by real-time RT-PCR. HA and NA genes of some isolated Influenza A (H3N2) viruses were amplified with spe-cific primers and then analyzed by sequencing and phylogenetic analysis. Results Influenza A (H3N2) virus was the predominant subtype circulating in Hangzhou during 2012 to 2017. It caused high morbidity in elderly people (Z=81. 039, P<0. 05). Most of the isolated influenza A (H3N2) viruses belonged to the phylogenetic clades of 3C. 3a and 3C. 2a. These viruses shared a homology of 96. 7％-100％ in nucleotide sequences of both HA and NA genes, but possessed several HA and NA mutations in antigenic sites. Con-clusions Influenza A (H3N2) virus was an important pathogen causing influenza epidemics in Hangzhou during 2012 to 2017. HA and NA genes showed many mutations in antigenic sites. No drug resistant virus was reported.
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BACKGROUND:The establishment of a safe, reliable and easily repeatable mouse model of nonalcoholic fatty liver disease is the prerequisite for the study of the diagnosis and treatment of the disease. OBJECTIVE:To establish a C57BL/6 mouse model of nonalcoholic fatty liver disease and observe changes of biochemical indicators, which can provide a theoretical basis for its pathogenesis and drug treatment. METHODS:Sixty healthy male C57BL/6 mice were randomly divided into a control group of 30 cases (normal diet), and a model group of 30 cases (high fat diet). Models of nonalcoholic fatty liver were established. At 8 weeks, body mass, liver index, and homogenate superoxide dismutase activity in the liver were detected. Changes in serum alanine aminotransferase, aspartate aminotransferase, triglyceride glycerol, cholesterol, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol were observed. Pathological examination was performed. RESULTS AND CONCLUSION:(1) Pathological sections showed that large droplets and smal lipid droplets in the mouse liver and spread the whole liver. Swel ing of the liver cel s, visible cytoplasmic vacuoles and obviously inflammatory changes in liver cel s were observed in the model group. (2) Body weight and liver index were significantly higher in the model group than in the control group (P<0.05). Superoxide dismutase activity was significantly reduced in the liver (P<0.05). (3) Triglycerides, cholesterol, and low-density lipoprotein cholesterol levels were significantly higher, but high-density lipoprotein cholesterol levels were significantly lower in the model group than in the control group (P<0.05). (4) Nonalcoholic fatty liver mouse model is ideal for high-fat diet-induced animal model. The method is simple, repetitive, and can provide a stable animal model for the study on the mechanism of nonalcoholic fatty liver disease and drug treatment.
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Objective To investigate the levels of blood pressure, blood lipid, blood glucose, body mass index (BMI) as well as the epidemiological characteristics of dyslipidemia, hyperglycemia, hypertension and metabolic syndrome of Hangzhou citizens. Methods A total of 28 990 citizens in Hangzhou city who underwent health checkup were recruited in this study, including 10 179 males and 18 811 females. The average age of subjects was 65.05 years. Subjects were asked to complete questionnaires regarding personal characteristics. The physical examination emphasized measurement of height, waist and blood pressure. Blood samples were collected and subjected to serum glucose, TC, HDL-C, LDL-C and TG measurements. The values of the examinations was described as xˉ± s . The ratios were compared with chi-square test. The trend analysis was conducted by linear correlation test. Results The prevalence of hypertension and metabolic syndrome was 17.1% and 11.2% respectively. And the prevalence of overweight/obesity and hyperglycemia was 36.3%,8.1%,16.4%respectively. It was indicated that the men had higher prevalence of hyperglycemia, hypertension, metabolic syndrome and overweight compared with women. However, as to the dyslipidemia, men and women were totally different. Women were more prone to suffer from hypercholesterolemia and elevation of low-density lipoprotein cholesterol. Men were apt to suffer from hypertriglyceridemia and reduction of high-density lipoprotein cholesterol. Divided the subjects by age into three groups, it was suggested that the rates of dyslipidemia, hyperglycemia, hypertension and overweight/obesity increased along with the increment of age in women. Although the rates of metabolic disorders were higher in the group of men, the trend of increase with age was not as significant as in women. It could be seen in men that dyslipidemia and overweight/obesity were reduced with the increase of age. Conclusion The metabolic disorders in Hangzhou citizens showed their own characteristics. It is suggested that multiple strategies targeting at different sexes and age-groups should be formulated to prevent and control the occurrence of metabolic diseases.
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Objective To investigate the formaldehyde emission rate of wood-based materials sold in Hangzhou and to ana-lyze its emission characteristics.Methods Four kinds of wood-based materials were selected and the formaldehyde emission rates were determined by applying the balancing concentration method of small environmental test chamber and the emission rates of different kinds of the materials were compared.Results A-level wood-based materials were of40%,B-level50%and C-level10%of the whole.The formaldehyde emission rates of these different kind of wood-based materials were significantly different (0.01