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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 establish a quick method to identify BMSC by fast violet B salt staining and evaluate the clinic value. Methods Smears of separated and cultured BMSC, bone marrow, pleural and ascitic fluids were made, then the staining of fast violet B salt was performed. The BMSC in aplastic anemia (AA), high hyperplasia and normal groups were counted and compared with each other. Meanwhile, the diagnostic value of this method to AA was evaluated. Results The cytoplasm of BMSC presented mauve, while the nucleus were negative, other cells such as myelocytes, nucleated erythrocytes, megakaryocytes, monocytes, macrophages, lymphocytes and plasmacytes were negative. The count of BMSC in AA, high hyperplasia and normal group was 1.07 ± 0. 29, 2. 26 ± 0. 37 and 1.58±0. 33, respectively. Significant differences were found between AA and high hyperplasia groups, AA and normal groups, high hyperplasia and normal groups, respectively (P < 0.01). The sensitivity, specificity, positive likelihood ratio and negative likelihood ratio of this method for diagnosis of AA were 90%, 93%, 12. 86 and 0. 11,respectively. Conclusions The fast violet B salt staining is simple and convenient. It could be used to identify BMSC and play an important role in judging the hyperplasia extent and differentiation of AA.
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BACKGROUND: Although we have gained much information about leadinduced organ damage, the effect of blood lead level on T cell subgroup is yet to be determined.OBJECTIVE: To assess the effect of blood lead level on T cell subgroup of children, and the association of T cell subgroup with threshold limit value of blood lead level.DESIGN: Comparative observation.SETTING: The Institute of Molecular Microorganism, Maternity and Child Care Hospital, Shanxi Provincial Children Hospital.PARTICIPANTS: Sixty children, (32 boys and 28 girls), aged 3-6 years with a mean of (4.5±1.5) years old, were selected from the suburbs of Taiyuan city between May 2003 and October 2003. Informed consents were obtained from all their guardians. The enrolled children according to their blood lead levels were assigned into three groups, 13 in Group Ⅰ with blood lead level ≥ 0.48 μmol/L, 20 in Group 2 with lead level ≥ 0.24 μmol/L but ＜ 0.48 μmoL/L and 27 in Group 3 with lead level ＜ 0.24 μmol/L.METHODS: Blood lead level and expression of T cell subgroup were measured with graphite furnace atomic absorption spectroscopy and immunofluorescence methods respectively. Student t test was used in data analysis, and linear correlation analysis was used to assess the correlation between blood lead level and expression of T cell subgroup.level and expression of T cell subgroup.pression of CD3 and ratio of CD4 to CD8 were lower in Group 1 (lead level ≥0.48 μmol/L) than Group 3 (lead level ＜ 0.24 μmol/L) (t=3.27,blood lead level showed had significant inverse correlation with CD3 expression and the ratio of CD4 to CD8(r=-0.689,-0.674,P ＜ 0.01).CONCLUSION: A blood lead level ≥ 0.48 μmol/L, is shown to significantly decrease the expression of CD3 and ratio of CD4 to CD8 in peripheral blood, which may impair the children's immunological function.
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BACKGROUND: Although we have gained much information about leadinduced organ damage, the effect of blood lead level on T cell subgroup is yet to be determined.OBJECTIVE: To assess the effect of blood lead level on T cell subgroup of children, and the association of T cell subgroup with threshold limit value of blood lead level.DESIGN: Comparative observation.SETTING: The Institute of Molecular Microorganism, Maternity and Child Care Hospital, Shanxi Provincial Children Hospital.PARTICIPANTS: Sixty children, (32 boys and 28 girls), aged 3-6 years with a mean of (4.5±1.5) years old, were selected from the suburbs of Taiyuan city between May 2003 and October 2003. Informed consents were obtained from all their guardians. The enrolled children according to their blood lead levels were assigned into three groups, 13 in Group Ⅰ with blood lead level ≥ 0.48 μmol/L, 20 in Group 2 with lead level ≥ 0.24 μmol/L but ＜ 0.48 μmoL/L and 27 in Group 3 with lead level ＜ 0.24 μmol/L.METHODS: Blood lead level and expression of T cell subgroup were measured with graphite furnace atomic absorption spectroscopy and immunofluorescence methods respectively. Student t test was used in data analysis, and linear correlation analysis was used to assess the correlation between blood lead level and expression of T cell subgroup.level and expression of T cell subgroup.pression of CD3 and ratio of CD4 to CD8 were lower in Group 1 (lead level ≥0.48 μmol/L) than Group 3 (lead level ＜ 0.24 μmol/L) (t=3.27,blood lead level showed had significant inverse correlation with CD3 expression and the ratio of CD4 to CD8(r=-0.689,-0.674,P ＜ 0.01).CONCLUSION: A blood lead level ≥ 0.48 μmol/L, is shown to significantly decrease the expression of CD3 and ratio of CD4 to CD8 in peripheral blood, which may impair the children's immunological function.
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AIM: To investigate whether celecoxib,a cyclooxygenase-2(COX-2) inhibitor,potentiates the anti-leukemia activity of STI571 in K562 cells.METHODS: K562 cells were treated with STI571,celecoxib or combination of both at different concentrations in suspension culture.Cell proliferation was documented by MTT assay,and cell apoptosis was determined by flow cytometry and morphology.Meanwhile,RT-PCR was applied to analyze the probable mechanism underlying the effects of the drugs.RESULTS: The combination of STI571 and celecoxib dramatically suppressed the proliferation of K562 cells,in which 0.25 ?mol/L STI571 and 40.0 ?mol/L celecoxib enhanced the inhibiting rate to 76.1%?1.6%.Furthermore,the combining administration of drugs significantly promoted the apoptosis induced by STI571,which showed characteristic changes of morphologic features and increase in sub-G_1 cells.By using RT-PCR technique,the expression of COX-2 had no decline by single administration of celecoxib or STI571.However,a progressive down-regulation was caused by coadministration of two drugs.In contrast with COX-2,the expression of VEGF had no changes at any time.CONCLUSION: The administration of celecoxib alone only inhibits the proliferation of K562 cells.Combination treatment with STI571 and celecoxib promotes the apoptosis induced by STI571.