ObjectiveTo investigate the expression and correlation of hypoxia inducible factor 1α (HIF-1α) and autophagy related molecules (Beclin1 and LC3B) in rat nucleus pulposus cells under hypoxia in vitro.MethodsThe nucleus pulposus cells were extracted from the nucleus pulposus of healthy adult Sprague Dawley rats and passaged. The 3rd generation cells were identified by HE staining and collagenase type Ⅱ immunofluorescence staining and randomly divided into 4 groups. The cells in group A were cultured for 8 hours under normal oxygen condition (37℃, 5%CO2, 20%O2); the cells in group B were cultured for 8 hours under hypoxia condition (37℃, 5%CO2, 1%O2); the cells in group C were transfected with HIF-1α-small interfering RNA and cultured for 8 hours under hypoxia condition; and the cells in group D were cultured with autophagy inhibitor 3-MA for 8 hours under hypoxia condition. Western blot and real-time fluorescence quantitative PCR (qRT-PCR) were used to detect the expressions of HIF-1α and autophagy related molecules (Beclin1 and LC3B) in all groups.ResultsHE staining of the 3rd generation nucleus pulposus cells showed that the cytoplasm was light pink and the nucleus was blue black, and the collagenase type Ⅱ immunofluorescence staining was positive. Western blot and qRT-PCR results showed that the relative expressions of HIF-1α, Beclin1, and LC3B proteins and genes in group B were significantly higher than those in group A (P<0.05); the relative expressions of HIF-1α, Beclin1, and LC3B proteins and genes in group C were significantly lower than those in group B (P<0.05). There was no significant difference in the relative expression of HIF-1α protein and gene between groups B and D (P>0.05); while the relative expressions of Beclin1 and LC3B proteins and genes in group D were significant lower than those in group B (P<0.05).ConclusionHypoxia can induce the expressions of HIF-1α and autophagy related molecules (Beclin1 and LC3B) in rat nucleus pulposus cells, and HIF-1α in rat nucleus pulposus cells under hypoxia is related to the expression of autophagy related molecules, that is, down-regulation of HIF-1α can significantly reduce the expression of autophagy related molecules, while the down-regulation of autophagy levels under hypoxia has no or little effect on the expression of HIF-1α.
Objective To evaluate the diagnostic value of all diagnostic tests for detecting armazide resistance in mycobacterium tuberculosis. Methods We searched PUBMED, EMBASE, CBM, CSJD and CJFD. QUADAS items were used to evaluate the quality of included studies. Meta-disc software was used to handle data from included studies. Results Twelve studies were included. Meta-analyses showed that the summary sensitivity and summary specificity of nitrate reductase assay were 92% and 99%, and those of BACTEC MGIT 960 system were 93% and 96%, respectively. The SROC of nitrate reductase assay and BACTEC MGIT 960 system were 0.9836 and 0.9862, respectively. Conclusion We recommend that proportion method can be replaced by nitrate reductase assay as a screening test for detecting armazide resistance in mycobacterium tuberculosis, and BACTEC 460 can be replaced by BACTEC MGIT 960 system as a final diagnostic test for detecting armazide resistance in mycobacterium tuberculosis.
Objective To evaluate the diagnostic accuracy of LiPA and phage-based assays in detecting rifampicin resistance in Mycobacterium tuberculosis. Methods A fully recursive literature search was conducted in PUBMED, EMBASE, CBMWeb, CSJD and CJFD. QUADAS items were used to evaluate the quality of the included studies. Meta-disc software was used to handle data from the included studies. SEN, SPE and SROC were used to assess the diagnostic accuracy of every individual diagnostic test. Results A total of 42 studies were included finally. (1) LiPA for detection of rifampicin resistant Mycobacterium tuberculosis: 7 studies took BACTEC 460 assay as the reference test, and meta-analysis showed that the summary SEN = 0.98, summary SPE = 0.98, SROC (AUC) = 0.9924; 6 studies chose proportion assay as the reference test, and meta-analysis showed that the summary SEN = 0.97, summary SPE = 1.00, SROC (AUC) = 0.9961; and 3 studies took both BACTEC 460 assay and proportion assay as the reference tests, and meta-analysis showed that the summary SEN = 0.92, summary SPE = 0.98, SROC (AUC) = 0.9842. (2)Seven studies detected the rifampicin resistant Mycobacterium tuberculosis using Phage amplification assays (Commercial), taking BACTEC 460 assay and proportion assay as the reference tests. Meta-analysis showed that the summary SEN = 0.95, summary SPE = 0.95, SROC (AUC) = 0.9842. (3) Seven studies detected the rifampicin resistant Mycobacterium tuberculosis using Phage amplification assays (in-house), taking BACTEC 460 assay, proportion assay and absolute concentration as the reference tests. Meta-analysis showed that the summary SEN = 0.98, summary SPE = 0.98, SROC (AUC) = 0.9949. (4)Seven studies detected the rifampicin resistant Mycobacterium tuberculosis using Luciferase reporter phage assays (In-house), taking BACTEC 460 assay, proportion assay and absolute concentration as the reference tests. Meta-analysis showed that the summary SEN = 0.98, summary SPE = 0.98, SROC (AUC) = 0.9788. Conclusion Current research confirms that Phage assay is a highly sensitive and specific test for the detection of rifampicin resistance in culture isolates and has a potential in improving the diagnostic accuracy of all diagnostic tests in detecting the rifampicin resistant Mycobacterium tuberculosis. LiPA is also a highly sensitive and specific test for the detection of rifampicin resistance, but the sensitivity appears to relatively decrease when it was used directly on clinical specimens. The results mentioned above need to be further confirmed by more high-quality studies.