Emergence of the colistin resistance gene,mcr-1,has attracted worldwide attention.Despite the prevalence of mcr-1-positive Escherichia coli(MCRPEC)strains in human carriage showing a significant decrease between 2016 and 2019,genetic differences in MCRPEC strains remain largely unknown.We therefore conducted a comparative genomic study on MCRPEC strains from fecal samples of healthy human subjects in 2016 and 2019.We identified three major differences in MCRPEC strains between these two time points.First,the insertion sequenceISApll1 was often deleted and the percentage of mcr-1-carrying IncI2 plasmids was increased in MCRPEC strains in 2019.Second,the antibiotic resistance genes(ARGs),aac(3)-Ⅳa and blaCTX-M-1,emerged and coexisted with mcr-1 in 2019.Third,MCRPEC strains in 2019 contained more viru-lence genes,resulting in an increased proportion of extraintestinal pathogenic E.coli(ExPEC)strains(36.1％)in MCRPEC strains in 2019 compared to that in 2016(10.5％),implying that these strains could occupy intestinal ecological niches by competing with other commensal bacteria.Our results suggest that despite the significant reduction in the prevalence of MCRPEC strains in humans from 2016 to 2019,MCRPEC exhibits increased resistance to other clinically important ARGs and contains more virulence genes,which may pose a potential public health threat.

Objective:To investigate the expression of anaplastic lymphoma kinase (ALK), tropomyosin receptor kinase (TRK), and recombinant C-Ros oncogene 1, receptor tyrosine kinase (ROS1) in Spitz tumors, and to analyze their associations with clinical and histopathological features of Spitz tumors.Methods:Clinical and histopathological characteristics, as well as follow-up data, were collected from patients with Spitz tumors at Department of Pathology, Hospital of Dermatology, Chinese Academy of Medical Sciences from January 2017 to August 2023, and retrospectively analyzed. Immunohistochemical staining for ALK, pan-TRK, and ROS1 was performed on skin tissues, and associations between the expression of these kinase proteins and clinicopathological features were analyzed.Results:A total of 57 patients with Spitz tumors were collected, including 36 females and 21 males. Immunohistochemical staining showed that 30 (52.6%) patients were positive for ALK, 4 (7.0%) were positive for ROS1, only 2 (3.5%) were positive for TRK, and 21 (36.8%) were negative for the three kinase proteins. Among the 30 ALK-positive patients, the median age was 9.5 years, 21 (70.0%) were females, and 15 (50.0%) presented with lesions on the face, which mainly manifested as papules or nodules; histologically, 29 (96.7%) patients had hypopigmented tumors with an exophytic growth pattern, and the tumor cells were mainly large and long spindle cells arranged in long cord-like, plexiform or fascicular patterns. Among the 4 ROS1-positive patients, there were 3 females and 1 male, presenting with exophytic papules or polyps; histologically, tumor cells were mostly arranged in small nests, without obvious clefts around cell nests. Two TRK-positive patients were both males aged 20 and 50 years respectively, and presented with brown and skin-colored flat papules, respectively; histologically, the tumors were located superficially with a flat base, and tumor cells spread in a pagetoid pattern in the epidermis, with some epithelioid cells and small cell nests. Among the 21 patients negative for the 3 kinase proteins, 9 were males and 12 were females, and they clinically presented with macules, papules and polypoid lesions; histologically, most tumors were located superficially, consisting of a mixture of epithelioid cells and spindle cells, with rare cytological atypia and mitotic figures, and 2 cases showed mild tissue structural and cellular atypia. Fifty-seven patients were followed up for 2 - 83.3 months, with a median follow-up of 19.2 months. Only 1 ALK-positive child experienced a recurrence, and no recurrence or lymph node metastasis was observed in the other cases.Conclusions:Among the three kinase proteins, ALK showed the highest positive rate in Spitz tumors in this study, while TRK- and ROS1-positive cases were sporadic. Histopathologically, ALK-positive Spitz tumor cells were mainly long spindle cells arranged in long cord-like or plexiform patterns, while TRK- and ROS1-positive Spitz tumors tended to have small cell nests. Both the kinase protein-positive and -negative Spitz tumors mostly had a good prognosis.

OBJECTIVE To systematically evaluate the efficacy and safety of midazolam and dexmedetomidine/propofol for the sedation of critically ill patients undergoing mechanical ventilation， and to provide evidence-based reference for clinical treatment. METHODS Retrieved from PubMed， Embase， Web of Science， Cochrane Library， Clinical trials. gov， China Journal Full Text Database， Chinese Science and Technology Journal Database， Wanfang database and China Biomedical Literature Database， the data on the efficacy and safety of midazolam and dexmetomidine/propofol for the sedation of critically ill patients undergoing mechanical ventilation were collected from the establishment of the database to March 31， 2023. After extracting data from clinical studies that met the inclusion criteria， the meta-analysis was conducted by using the RevMan 5.3 statistical software. RESULTS A total of 31 literature were included， with a total of 2 765 patients. Results of meta-analysis showed that the mechanical ventilation time [MD＝14.13， 95%CI （13.75， 14.52）， P＜0.000 01] and the length of hospitalization in the intensive care unit [MD＝0.92， 95%CI （0.54， 1.30）， P＜0.000 01] of patients in the midazolam group was longer than dexmedetomidine/ propofol group. The incidence of bradycardia in midazolam group was lower dexmedetomidine/propofol group [OR＝0.60， 95%CI （0.41， 0.90）， P＝0.01]， but there was no statistically significant difference in the incidence of hypotension between the two groups [OR＝0.69， 95%CI （0.47， 1.01）， P＝0.06]. The incidence of delirium [OR＝3.88， 95%CI （2.74， 5.49）， P＜0.000 01]， ventilator- associated pneumonia [OR＝2.32， 95%CI （1.19， 4.51）， P＝0.01]， and respiratory depression [OR＝5.70， 95%CI （3.09， 10.52）， P＜0.000 01] in midazolam group were higher than dexmedetomidine/propofol group. CONCLUSIONS Compared with dexmedetomidine/propofol， midazolam increases patients’ mechanical ventilation time and the length of hospitalization in the intensive care unit in terms of efficacy， and increases the risk of delirium and pulmonary complications in terms of safety， but has a smaller cardiovascular impact.

Objective To construct intrauterine adhesion (IUA) mouse models induced by two different concentrations of ethanol injury, compare the phenotypes, and optimize a more stable IUA modeling method. Methods Twenty 8-week-old female C57BL/6N mice were randomly divided into two groups: the 95% ethanol injury group and the 50% ethanol injury group. Using a self-control method, the left uterine horn was infused with ethanol to establish the IUA model, while the right uterine horn was infused with saline as the sham operation. Five mice from each group were euthanized on day 7 and 15 after modeling, and uterine tissues were collected. Hematoxylin-eosin (HE) staining was used to observe the endometrial pathology, and Masson staining was used to assess the degree of endometrial fibrosis. Quantitative real-time PCR was employed to detect the expression levels of fibrosis markers and pro-inflammatory factors in the uterine tissues. Results Compared to the sham operation, these two ethanol injury led to a significant reduction in elasticity of the uterus, an increase in inflammatory infiltration, and a marked increase in the degree of fibrosis on day 7 after modeling (P<0.05). The 95% ethanol injury group showed a significant decrease in endometrial thickness (P<0.05), whereas no significant change was observed in the 50% ethanol injury group when compared to the sham operation (P>0.05). The expression levels of fibrotic marker molecules collagen type Ⅳ alpha 1 chain (Col4A1), α-smooth muscle actin (α-SMA), transforming growth factor-β (TGF-β), and pro-inflammatory factors tumor necrosis factor-α (TNF-α) and interleukin-1β (IL-1β) were significantly elevated in the 50% ethanol injury group when compared to the sham operation (P<0.05), although there was an increasing trend of the same markers in the 95% ethanol injury group, the differences were not statistically significant (P>0.05). On day 15 after modeling, the histopathological changes in both ethanol injury groups were not significant when compared to the sham operation, the expression levels of Col4A1, TGF-β, TNF-α and IL-1β remained significantly higher in the 50% ethanol injury group (P<0.05), while only IL-1β was significantly elevated in the 95% ethanol injury group (P<0.05). Conclusion Uterine infusion with 95% ethanol results in more marked histopathological changes in the IUA mouse model compared to the 50% ethanol injury group. The 95% ethanol injury model is suitable for histopathological studies. However, the 50% ethanol injury group shows higher expression levels of fibrosis markers and pro-inflammatory factors compared to the 95% ethanol injury group, suggesting that the 50% ethanol injury model is more suitable for molecular pathological study.