Objective:To analyze the contamination characteristics and pathogenic potential of Listeria monocytogenes (LM) in pre-packaged and refrigerated ready-to-eat cooked meat products in Chengdu City. Methods:From September 2022 to May 2023, pre-packaged and refrigerated ready-to-eat cooked meat products were collected from six districts and counties in Chengdu City. Qualitative and quantitative determination of LM was performed on these samples. Whole genome sequencing was carried out on the isolated strains. Different ST strains were selected for cell adhesion and invasion experiments. The results were expressed as adhesion rate and invasion rate. One-way ANOVA was used for comparison between groups, and the Dunnett t-test was used for pairwise comparison. Results:A total of 145 samples were collected, and LM was detected and isolated in 29 samples. The total detection rate was 20.00%, and the detection rate of braised pork was the highest (68.18%). The contamination level of LM in 9 samples (31.03%) was greater than 100.00 MPN/g. The 29 strains of Listeria monocytogenes belonged to 7 STs, including ST 3 (27.59%), ST 8 (17.24%) and ST 87 (13.79%). The strain of ST 87 carried Listeria pathogenicity islands 4 (LIPI-4), which was a highly virulent strain. The medium and high virulence strains accounted for 79.31%. Some moderately virulent and highly virulent strains of ST 8 and ST 87 were closely related to clinical patient strains. Some LM isolates of the same ST type had little SNP differences (1-6) in the same manufacturer at different stages. In vitro cell experiments showed that the highly virulent strain ST 87 had the strongest adhesion and invasion ability towards Caco-2 cells. Conclusion:The pre-packaged and refrigerated cooked meat products have a high contamination rate. Some samples have high contamination levels and carry medium and high virulence strains, posing potential health risks to human beings. LM residues continue to persist in some manufacturers′ production and processing stages.

Objective:To analyze the contamination characteristics and pathogenic potential of Listeria monocytogenes (LM) in pre-packaged and refrigerated ready-to-eat cooked meat products in Chengdu City. Methods:From September 2022 to May 2023, pre-packaged and refrigerated ready-to-eat cooked meat products were collected from six districts and counties in Chengdu City. Qualitative and quantitative determination of LM was performed on these samples. Whole genome sequencing was carried out on the isolated strains. Different ST strains were selected for cell adhesion and invasion experiments. The results were expressed as adhesion rate and invasion rate. One-way ANOVA was used for comparison between groups, and the Dunnett t-test was used for pairwise comparison. Results:A total of 145 samples were collected, and LM was detected and isolated in 29 samples. The total detection rate was 20.00%, and the detection rate of braised pork was the highest (68.18%). The contamination level of LM in 9 samples (31.03%) was greater than 100.00 MPN/g. The 29 strains of Listeria monocytogenes belonged to 7 STs, including ST 3 (27.59%), ST 8 (17.24%) and ST 87 (13.79%). The strain of ST 87 carried Listeria pathogenicity islands 4 (LIPI-4), which was a highly virulent strain. The medium and high virulence strains accounted for 79.31%. Some moderately virulent and highly virulent strains of ST 8 and ST 87 were closely related to clinical patient strains. Some LM isolates of the same ST type had little SNP differences (1-6) in the same manufacturer at different stages. In vitro cell experiments showed that the highly virulent strain ST 87 had the strongest adhesion and invasion ability towards Caco-2 cells. Conclusion:The pre-packaged and refrigerated cooked meat products have a high contamination rate. Some samples have high contamination levels and carry medium and high virulence strains, posing potential health risks to human beings. LM residues continue to persist in some manufacturers′ production and processing stages.

ObjectiveTo explore the possible mechanism of Chuanxiong （Rhizoma Chuanxiong） & Tianma （Rhizoma Gastrodiae） herbal pair in treating migraines based on AMP-activated protein kinase （AMPK）/transient receptor potential A1 channel （TRPA1） pathway. MethodsForty-eight healthy male SD rats were randomly divided into control group， model group， and Chuanxiong Tianma medication group， with 16 rats in each group. The control group and model group were given 10 ml/kg of normal saline by gavage， while the Chuanxiong Tianma medication group was given 0.675 g/kg of Chuanxiong Tianma herbal pair by gavage， once daily for 8 consecutive days in both groups. Migraime model was performed before the last administration， with subcutaneous injection of 10 ml/kg of normal saline in the control group， and subcutaneous injection of 10 ml/kg of nitroglycerin in the model group and Chuanxiong Tianma medication group. The Von Frey filament was used to measure the periorbital mechanical pain threshold of rats. The enzyme-linked immunosorbent assay （ELISA） was used to determine the levels of calcitonin gene-related peptide （CGRP） in rat serum and cerebrospinal fluid. The nitric oxide （NO） assay kit was used to determine the NO level in serum and cerebrospinal fluid. RT-PCR was usedto detect the mRNA expression levels of immediate-early genes in the trigeminal ganglion of rats （c-Fos）， CGRP， transient receptor potential V1 channel （TRPV1）， AMPK alpha subunit （PRKAA）， and TRPA1. Immunofluorescence was used to detect the number of c-Fos-positive cells in the trigeminal cervical complex （TCC） and the protein expression levels of phosphorylated AMPK （pAMPK） and TRPA1 in the trigeminal ganglion. ResultsCompared to those in the control group， the mechanical stimulation threshold and pAMPK protein expression in the model group decreased， while the levels of CGRP and NO in serum， c-Fos， CGRP， TRPV1 and TRPA1 mRNA levels in the trigeminal ganglion， TRPA1 protein expression， and the number of c-Fos-positive cells in the TCC significantly increased （P＜0.05）. Compared to those in the model group， the mechanical stimulation threshold and pAMPK protein expression in the Chuanxiong Tianma medication group significantly increased， while the levels of CGRP and NO in serum， c-Fos， CGRP， TRPV1 and TRPA1 mRNA levels in the trigeminal ganglion， TRPA1 protein expression， and the number of c-Fos-positive cells in the TCC significantly decreased （P＜0.05）. ConclusionChuanxiong Tianma herbal pair may improve migraine symptoms by regulating the AMPK/TRPA1 pathway in the trigeminal ganglion and increasing the mechanical pain threshold.

ObjectiveTo assess the efficacy of subglottic secretion drainage for preventing ventilatorassociated pneumonia.MethodsData of relevant randomized controlled trials (RCT) from January 1991 to June 2010 were collected,and data were split into two groups,namely draining group and non-draining group.Meta analysis of ventilator-associated pneumonia was carried out for finding the incidence and mortality in patients with mechanical ventilation using the methods recommended by the Cochrane Collaboration.ResultsSeven RCTs met the inclusion criteria and 1647 patients were enrolled.Subglottic secretion drainage reduced the incidence of ventilator-associated pneumonia ( OR =0.45,95％ confidence interval [CI]:0.32 - 0.63 ),primarily by reducing early-onset pneumonia.But the mortalities of ventilator associated pneumonia were not significantly different between the two groups ( OR =1.03,95％ confi dence interval [CI]:0.75 - 1.41 ).ConclusionsSubglottic secretion drainage appeared effective in preventing ventilator associated pneumonia among patients expected to require ＞48 hours of mechanical ventilation,but the mortality was unchanged.