ABSTRACT
Objective:To investigate the etiological diagnostic value of metagenomic sequencing in central nervous system (CNS) infectious diseases.Methods:A total of 170 patients with central nervous system infection admitted to the First Affiliated Hospital of Zhengzhou University from January 2018 to June 2020 were selected as the study subjects according to inclusion and exclusion criteria. General clinical data and pathogen test results were collected. All included patients underwent routine examination and mNGS test, and were divided into the conventional method test group and mNGS test group according to the test results. The measurement data conforming to normal distribution were represented by ± s; The measurement data that did not conform to normal distribution were represented by median and interquartile range. The classification data were expressed by the number of cases and percentage( n,%), and were compared by χ2 test or Fisher's exact test. Consistency test was represented by Kappa value. The detection of pathogenic microorganisms by the two methods and the rule of pathogen spectrum were compared and analyzed. Results:The overall positive rate of mNGS in CNS infectious diseases was higher than that of conventional methods (58.23% vs. 18.82%), and the difference was statistically significant ( P<0.01). Among the 20 samples which were both positive by the two methods, 10 cases were completely pathogenic, 5 cases were partially consistent and 5 cases were completely inconsistent. In the detection of tuberculous nervous system infection, the positive rates were 66.7%, 53.8%, 44.0%, 40.0%, 4.0% in blood T-SPOT, cerebrospinal fluid mNGS, ADA, Mycobacterium tuberculosis DNA and tuberculous specific antibody, respectively. The positive rate of acid-fast staining was 0. The positive rate of mNGS combined with conventional method was 80.8%. Conclusions:The detection rate of mNGS in CNS infection is better than that of conventional methods. However, it does not show obvious superiority in the detection rate of Mycobacterium tuberculosis associated nervous system infection. In general, mNGS detection of pathogenic bacteria is more extensive, which is conducive to a thorough and comprehensive understanding of the bacterial characteristics of central nervous system infection. The combination of the two methods can make up for the deficiency of clinical routine detection to a certain extent, and can maximize the detection rate.
ABSTRACT
BACKGROUND: Imatinib has a significant pro-apoptosis effect on chronic myelogenous leukemia (CML), but there are still some patients being resistant to it. Human umbilical cord mesenchymal stem cells (hUC-MSCs) affect the apoptosis of a variety of hematologic malignancies. However, the impacts of hUC-MSCs on the apoptosis of CML cells induced by imatinib remain unclear.OBJECTIVE: To investigate whether hUC-MSCs have an influence on the apoptosis of K562 cells induced by imatinib and to reveal the possible underlying mechanism.METHODS: K562 cells were cultured with hUC-MSCs or/and imatinib. Cellular apoptosis was measured with Annexin-V and PI staining by flow cytometry analysis. The protein expressions of Bax, Bcl-2, caspase-3, caspase-9 and cleaved-PARP in K562 cells were detected by western blot assay. Pan-caspase inhibitor Z-VAD-FMK was used to block apoptosis in each group, and during this process the effect of caspase apoptosis signaling pathway was detected.RESULTS AND CONCLUSION: The apoptosis of K562 cells was enhanced, when imatinib was combined with hUC-MSCs. Western blot analysis showed that the expression of pro-apoptotic protein Bax was enhenced and the expression of anti-apoptotic protein Bcl-2 was suppressed. Furthermore, the cleaved forms of caspase-9, caspase-3 and PARP in K562 cell were higher in the hUC-MSCs+imatinib group than in the imatinib group. The apoptosis of K562 cells induced by the hUC-MSCs combined with imatinib was significantly inhibited by Z-VAD-FMK. In conclusion, these findings indicate that hUC-MSCs can enhance imatinib-induced apoptosis of K562 cells by activating caspase apoptosis signaling pathway.