The polymyxins are important antimicrobial agents against antibiotic-resistant gram-negative bacilli. In 2020, the Clinical and Laboratory Standards Institute modified the clinical breakpoints for polymyxin susceptibility test by eliminating the "susceptible" interpretive category, only reporting intermediate (≤2 mg/L) and resistant (≥4 mg/L). However, the European Committee on Antimicrobial Susceptibility Testing recommended the use of clinical breakpoints of ≤2 mg/L as susceptible and >2 mg/L as resistant. The first-line laboratorians and clinicians in China have been perplexed by the inconsistence of international polymyxin clinical breakpoints and discouraged by the difficulty of conducting polymyxin susceptibility testing. Therefore, it is urgently needed to make it clear for the laboratorians in China to know how to accurately carry out polymyxin susceptibility testing and standardize the interpretation of susceptibility testing results. To this end, the experts from relevant fields were convened to formulate this consensus statement on the testing and clinical interpretation of polymyxin susceptibility. Relevant recommendations are proposed accordingly for laboratorians and clinicians to streamline their daily work.

Objective: Several COVID-19 patients have overlapping comorbidities. The independent role of each component contributing to the risk of COVID-19 is unknown, and how some non-cardiometabolic comorbidities affect the risk of COVID-19 remains unclear. Methods: A retrospective follow-up design was adopted. A total of 1,160 laboratory-confirmed patients were enrolled from nine provinces in China. Data on comorbidities were obtained from the patients' medical records. Multivariable logistic regression models were used to estimate the odds ratio ( Results: Overall, 158 (13.6%) patients were diagnosed with severe illness and 32 (2.7%) had unfavorable outcomes. Hypertension (2.87, 1.30-6.32), type 2 diabetes (T2DM) (3.57, 2.32-5.49), cardiovascular disease (CVD) (3.78, 1.81-7.89), fatty liver disease (7.53, 1.96-28.96), hyperlipidemia (2.15, 1.26-3.67), other lung diseases (6.00, 3.01-11.96), and electrolyte imbalance (10.40, 3.00-26.10) were independently linked to increased odds of being severely ill. T2DM (6.07, 2.89-12.75), CVD (8.47, 6.03-11.89), and electrolyte imbalance (19.44, 11.47-32.96) were also strong predictors of unfavorable outcomes. Women with comorbidities were more likely to have severe disease on admission (5.46, 3.25-9.19), while men with comorbidities were more likely to have unfavorable treatment outcomes (6.58, 1.46-29.64) within two weeks. Conclusion Besides hypertension, diabetes, and CVD, fatty liver disease, hyperlipidemia, other lung diseases, and electrolyte imbalance were independent risk factors for COVID-19 severity and poor treatment outcome. Women with comorbidities were more likely to have severe disease, while men with comorbidities were more likely to have unfavorable treatment outcomes.
Adult ; Aged ; COVID-19/virology* ; China/epidemiology* ; Comorbidity ; Female ; Humans ; Male ; Middle Aged ; Retrospective Studies ; Severity of Illness Index ; Treatment Outcome

BACKGROUND: Cell-free stem cell therapy has been an issue of concern, but there is no conclusion on how to extract high-quality exosomes. OBJECTIVE: To extract exosomes from human umbilical cord mesenchymal stem cells by using three different methods, and then to screen the optimal method. METHODS: Exosomes were extracted from human umbilical cord mesenchymal stem cells by using the Total Exosome Isolation test kit, Exo Quick test kit and differential ultracentrifugation method, respectively. Then, transmission electron microscopy was used for morphological observations, BCA was utilized to quantify the protein, and western blot assay was applied to detect surface markers CD9, CD81 and CD63. RESULTS AND CONCLUSION: Extraction of exosomes was completed by all the three methods, and round or oval membranous vesicles were observed under the transmission electron microscope. The protein content and purity of exosomes was highest in the differential ultracentrifugation group, followed by the Exobiology Quick kit group, and lowest in the Total Exosome Isolation kit group, and there were significant differences among the three groups (P < 0.05). Under the same protein concentration, surface specific markers, CD81, CD63 and CD9, were expressed highest in the differential ultracentrifugation group, followed by the Exobiology Quick kit group, and lowest in the Total Exosome Isolation kit group. The operating time was significantly lower in the Exobiology Quick kit group compared with the other two groups (P < 0.05). To conclude, despite a longer operating time, the differential ultracentrifugation method is a rational method to extract enough exosomes with relative high purity.

Objective To achieve the purpose of promoting movement function of the injury nerve by using the joint therapy of NT- 3- HUMSCs and SOCS3 gene silencing on SD rats'spinal cord injury. Methods (1) We used adherence method in vitro human umbilical cord-derived mesenchymal cells (HUMSC) during separation, purification and identification. (2) Then constructed NT-3 gene eukaryotic expression vector, which was transfected into its HUMSC, and constructed NT-3- HUMSC cell survival in vitro assay conditions and NT-3 expression. (3) We selected specific targets for SOCS3 screening and for sequence homology analysis. A negative control group was established. siRNA was designed and synthesized in vitro detection. (4) SD rats with spinal cord injury model were divided into two categories: (1) sham group with 10 rats; (2) T12 whole spinal cord injury model with 40 rats. The 40 rats were randomly divided into four groups with 10 rats in each group (saline treatment group,siRNA +NT-3-HUMSCs treatment group,NT-3-HUMSCs treatment group and siRNA treated group) . Motor function of the rats were evaluated respectively in 1, 2 and 3 months after the modeling was established successfully.Results(1) siRNA + NT-3-HUMSCs treatment group's BBB scores was significantly higher than NT-3-HUMSCs, SOCS3-siRNA and physiological saline groups ( P＜0.05) . (2) The grid climbing experiments showed that the neural functional recovery performed better in siRNA+the NT- 3- HUMSCs treatment group compared to the NT - 3 - HUMSCs, SOCS3 - siRNA and physiological saline groups (P＜0.05) . Conclusion The NT- 3- HUMSCs joint SOCS3 gene silencing in the treatment of SD rat spinal cord injury can improve the motor function of SD rat spinal cord injury.

Objective To investigate the effect of joint therapy by NT-3-HUMSCs and SOCS3 gene silencing in promoting the injury nerve regeneration repair after spinal cord injury in SD rats. Methods (1) Adherence method was used to culture human umbilical cord-derived mesenchymal cells (HUMSC) in vitro for separation, purification and identification. (2) We constructed NT-3 gene eukaryotic expression vector, and used gene transfection technology into its HUMSC, and tested the survival of NT-3-HUMSC cells and NT-3 expression in cells. (3) We screened specific targets of SOCS3, made sequence homology analysis, and set a negative control, designed and synthesized siRNA and detected the function. (4) SD rats model of spinal cordinjury were established and divided into: 1. sham group 10; 2.T12 whole spinal cord injury model 40, were randomly divided into four groups, respectively; saline treatment group 10; siRNA + NT-3-HUMSCs treatment group 10; NT-3-HUMSCs treatment group 10; siRNA treated group 10. After each group above modeling success, they received respectively the neural electrophysiological monitoring for 12 weeks survival. (5) We perfused SD rats for fixation and collect samples, and observed the local glial scar degradation situation and axon regeneration, meanwhile, used biotin glucan fluorescent (BDA) anterograde tracing. The injury transplant area-host junction spinal cord tissues were collected to observe the corticospinal tract regeneration under microscope. Results (1) In siRNA + NT-3-HUMSCs treatment group, the transection syringomyelia was significantly reduced as compared with normal saline group (P ＜ 0.05). (2) BDA anterograde tracing results showed that in the siRNA + NT-3-HUMSCs treatment group, neural axon grew significantly compared with the normal saline group. (3) Neural electrophysiological testing 12 weeks after injury: in the treatment group, the incubation period P40 was shorter as compared with control group; in siRNA + NT-3-HUMSCs treatment group, the incubation period was shorter obviously than normal saline, but the amplitude increased obviously (P ＜ 0.05). Conclusion NT-3-HUMSCs joint with SOCS3 gene silencing can promote the injury nerve regeneration repair in the treatment of SD rat spinal cord injury.