Objective:To establish and evaluate a rapid nucleic acid detection method for SARS-CoV-2 based on COYOTE ? Flash20 real-time fluorescent quantitative PCR instrument. Methods:A rapid reaction system was constructed by using specific primer and probe sets targeting ORF1ab and N gene of SARS-CoV-2, and the sensitivity and specificity of the system were verified. At the same time, 108 clinical samples of COVID-19 were used to evaluate the application of this method.Results:The detection method did not require nucleic acid extraction, and the manual operation time was only one minute. After the sample was sent to the system, the test could be completed in 30 minutes. The detection limit of this method was 4×10 2 copies/ml. It had no cross-reactivity with other human coronaviruses (including HCoV-229E, HCoV-NL63, HCoV-OC43, HCoV-HKU1, SARS-CoV and MERS-CoV) and other respiratory viruses. The evaluation of clinical sample application showed that the total coincidence rate with the conventional RT-qPCR which required nucleic acid extraction was 98.15%. Conclusions:Through the application evaluation of the rapid fluorescent quantitative PCR method of SARS-CoV-2, it was found that the method was simple, fast, specific and sensitive, and it was suitable for real-time and rapid detection needs in varieties of situations.

Objective To observe the effects of hyperbaric oxygen (HBO) on the expressions of stromal derived factor-1 (SDF-1) and CXC chemokine receptor 4(CXCR4) in rats with traumatic brain injury and also to discuss potential mechanism of HBO in the protection of the nerve system of the rats with TBI.Methods The experimental models of traumatic brain injury were developed by modified Feeney free-falling method.Seventy-two SD male rats were randomly divided into 3 groups: the sham surgery group, the model group and the HBO group, each consisting of 24 rats.Then, in accordance with HBO intervention time, the HBO group was subdivided into the 3-day and 10-day subgroups.The rats in the HBO group received HBO therapy 24 hours after development of the model, one session a day.Recovery of the nerve system, 24 hours after development of the model, 3 and 10 days after therapy, was assessed by using Neurological Severity Scores (NSS), and neurological function recovery was compared between the groups.At the same time, samples of damaged brain tissues were taken for the detection of expression levels of SDF-1 and CXCR4 by using Western blotting.Results (1)Neurological function deficiency was not noted in the sham surgery group.There were no significant differences in neurological function deficiency scores detected 24 hours after the development of the model, when comparisons were made between the model group and the HBO group(P ＞0.05).Three and 10 days after therapy, neural function recovered gradually, with the neural function deficiency scores of the HBO group being(8.7 ± 0.4)and(4.7 ±0.6)respectively, which were obviously lower than those of the model group(10.5 ±0.6 and 6.40.6 respectively)(P ＜0.01).(2)The expressions of SDF-1 and CXCR4 in the sham surgery group were low, and there was no statistical significance in the expression levels at different time points(P ＞0.05).Three days after therapy, the expression levels of SDF-1 and CXCR4 for the model group were all significantly increased, as compared with those of the sham surgery group(P ＞ 0.05).Ten days after therapy, the expression level of SDF-1 for the model group was decreased, which tended to be the identical level of the sham surgery group(P ＞0.05).Though the expression level of CXCR4 was also decreased, it was obviously higher than that of the sham surgery group (P ＞ 0.01).Three and 10 days after therapy, the expression levels of SDF-1 and CXCR4 for the HBO group were significantly increased, as compared with those of the model group(P ＞ 0.01).Conclusions HBO therapy could accelerate neurological function recovery of the rats with TBI and promote homing of endogenous mesenchymal stem cells to the injured brain tissues by upregulating SDF-1/CXCR4 axis.

Objective To observe the effects of hyperbaric oxygen (HBO) on the expressions of stromal derived factor-1 (SDF-1) and CXC chemokine receptor 4(CXCR4) in rats with traumatic brain injury and also to discuss potential mechanism of HBO in the protection of the nerve system of the rats with TBI.Methods The experimental models of traumatic brain injury were developed by modified Feeney free-falling method.Seventy-two SD male rats were randomly divided into 3 groups: the sham surgery group, the model group and the HBO group, each consisting of 24 rats.Then, in accordance with HBO intervention time, the HBO group was subdivided into the 3-day and 10-day subgroups.The rats in the HBO group received HBO therapy 24 hours after development of the model, one session a day.Recovery of the nerve system, 24 hours after development of the model, 3 and 10 days after therapy, was assessed by using Neurological Severity Scores (NSS), and neurological function recovery was compared between the groups.At the same time, samples of damaged brain tissues were taken for the detection of expression levels of SDF-1 and CXCR4 by using Western blotting.Results (1)Neurological function deficiency was not noted in the sham surgery group.There were no significant differences in neurological function deficiency scores detected 24 hours after the development of the model, when comparisons were made between the model group and the HBO group(P ＞0.05).Three and 10 days after therapy, neural function recovered gradually, with the neural function deficiency scores of the HBO group being(8.7 ± 0.4)and(4.7 ±0.6)respectively, which were obviously lower than those of the model group(10.5 ±0.6 and 6.40.6 respectively)(P ＜0.01).(2)The expressions of SDF-1 and CXCR4 in the sham surgery group were low, and there was no statistical significance in the expression levels at different time points(P ＞0.05).Three days after therapy, the expression levels of SDF-1 and CXCR4 for the model group were all significantly increased, as compared with those of the sham surgery group(P ＞ 0.05).Ten days after therapy, the expression level of SDF-1 for the model group was decreased, which tended to be the identical level of the sham surgery group(P ＞0.05).Though the expression level of CXCR4 was also decreased, it was obviously higher than that of the sham surgery group (P ＞ 0.01).Three and 10 days after therapy, the expression levels of SDF-1 and CXCR4 for the HBO group were significantly increased, as compared with those of the model group(P ＞ 0.01).Conclusions HBO therapy could accelerate neurological function recovery of the rats with TBI and promote homing of endogenous mesenchymal stem cells to the injured brain tissues by upregulating SDF-1/CXCR4 axis.