Partial pressure of oxygen level at admission as a predictor of postoperative pneumonia after hip fracture surgery in a geriatric population: a retrospective cohort study.

OBJECTIVE: To identify whether the partial pressure of oxygen in arterial blood (PaO2) level at admission is an independent risk factor as a prognostic biomarker to predict postoperative pneumonia (POP) in the geriatric population who have undergone hip fracture surgical repair at our hospital. DESIGN: A retrospective cohort study. SETTING: This is a retrospective chart review of POP after hip fracture surgery in China. PARTICIPANTS: In training cohort, patients aged ≥65 years who had hip fracture surgery between 1 January 2018 and 30 November 2019. In the validation cohort, a series of patients who underwent hip fracture surgery between 1 January 2020 and 28 February 2020. INTERVENTIONS: Receiver operating characteristic (ROC) analysis was used to obtain the area under the ROC curve (AUC) and cut-off values of PaO2 to predict POP. A binomial logistic regression model was used to identify potential risk factors for POP by analysing demographic distribution factors, laboratory results, preoperative comorbidities and surgical factors. Then the regression model was validated using an independent cohort. RESULTS: In the training cohort, ROC curves were generated to compare the predictive performance of PaO2 for the occurrence of POP, and the area under the receiver operating characteristic curve (AUC) was 0.653 (95% CI 0.577 to 0.729, p<0.0001), with sensitivity and specificity values of 60.0% and 63.8%, respectively. The cut-off value of the PaO2 for POP was 72.5 mm Hg. Binary logistic regression analysis revealed that hypoxaemia (PaO2 <72.5 mm Hg) at hospital admission (OR=3.000, 95% CI 1.629 to 5.528; p<0.0001) was independent risk factors associated with POP after hip fracture surgery. In the validation cohort, PaO2 had a predictive effect for POP (AUC 0.71, 95% CI 0.541 to 0.891). CONCLUSIONS: The current study revealed that the PaO2 level at hospital admission is a simple and widely available biomarker predictor of POP after hip fracture surgery in elderly patients.

Clinical Characteristics of Foreign-Imported COVID-19 Cases in Xi'an, China.

BACKGROUND: Effective management of foreign-imported COVID-19 cases is a new and great challenge for China. Our study focused on the foreign-imported COVID-19 cases to provide detailed data for insights into the prevention, early diagnosis, treatment and control of imported COVID-19. METHODS: For this observational and retrospective study, we investigated the clinical characteristics of imported COVID-19 cases that were confirmed by real-time RT-PCR in the Xi'an Public Health Center from 29 March 2020 to 31 August 2020. RESULTS: Of the 79 patients with COVID-19, 19 (24.1%) had exposure to confirmed COVID-19 patients, 15 (19.0%) had exposure to suspicious COVID-19 patients, and 45 (56.9%) had an unclear history of exposure to confirmed patients. The mean age of the patients was 38 years, and 70 (88.7%) patients were male. Except for 2 severe cases, the remaining 58 (73.4%) cases displayed mild or moderate symptoms, and 19 (24.2%) infected patients were asymptomatic. Twenty-one (26.6%) patients were not diagnosed until a third or later nucleic acid test. Ten (12.7%) patients had chronic diseases. The most common manifestations of the patients were cough [18 (22.8%) cases], fever [9 (11.4%) cases] and sore throat [9 (11.4%) cases]. Forty-one (51.9%) cases showed abnormal chest CT images, To date, all patients have been discharged, and no patient has died. CONCLUSION: The imported COVID-19 cases in Xi'an were mainly young and middle-aged adults with mild or moderate symptoms who had a low rate of comorbidity, showed favourable laboratory and chest CT images, and had a better prognosis. Notably, for suspected COVID-19 cases, at least three consecutive nucleic acid tests should be carried out to avoid missed detection of infected patients. Except for severe cases, high-level medical resources are not necessary in most cases.

Galectin-9 regulates follicular helper T cells to inhibit humoral autoimmunity-induced pulmonary fibrosis.

Interstitial pneumonia with autoimmune features (IPAF) is an unexplained disease state characterized by autoimmunity and pulmonary fibrosis. Exploring the pathogenesis of IPAF is helpful for the treatment of interstitial pneumonia and idiopathic pulmonary fibrosis. In this study, we observed that the lung Galectin-9 (Gal-9) of IPAF patients was significantly reduced, which was significantly related to lung dysfunction and abnormal humoral immunity. Moreover, an overreactive germinal center (GC) reaction in the lung lymph nodes (LNs) of Gal-9-deficient mice was found to be related to abnormally active follicular helper T cells (Tfh) cells. The lack of Gal-9 ligand in Tfh cells can lead to excessive transcriptional programming and differentiation and help GC B cells. Gal-9 deficiency caused an abnormal humoral immune response in mice, leading to excessive deposition of nonspecific autoantibodies in mice and chronic lung fibrosis. Our research reveals the important regulatory role of gal-9 in Tfh cells and a possible target for the treatment of IPAF.

MiR-155 controls follicular Treg cell-mediated humoral autoimmune intestinal injury by inhibiting CTLA-4 expression.

High expression levels of miR-155 are involved in the pathogenesis of inflammatory bowel disease (IBD). We observed an increase in miR-155 in peripheral regulatory T (Treg) cells from IBD patients. Mice that specifically overexpress miR-155 in Foxp3+ Treg cells exhibit spontaneous autoimmunity and more severe dextran sulfate sodium (DSS)-induced intestinal injury. MiR-155 overexpression can lead to a lack of follicular Treg (Tfr) cells and central Treg (cTreg), whereas DSS treatment further depletes the Tfr cells. Furthermore, miR-155 can target the expression of CTLA-4 in cTreg and Tfr, directly inhibiting Tfr cell production and promoting enhanced germinal center (GC) B cell activation and autoantibody overproduction. This outcome may be the cause of severe intestinal injury in patients with autoimmune IBD.

Preoperative Serum Albumin Level As A Predictor Of Postoperative Pneumonia After Femoral Neck Fracture Surgery In A Geriatric Population.

PURPOSE: Femoral neck fracture usually occurs in the geriatric population. Postoperative pneumonia (POP) is known to be devastated, and it is the most frequent complication among patients receiving surgical treatment for femoral neck fractures. However, whether patients who have hypoalbuminaemia are susceptible to the development of POP is a serious concern, although it has not been investigated. We attempted to investigate the association between newly developed POP and hypoalbuminaemia and to identify whether hypoalbuminaemia is an independent risk factor for POP after femoral neck fracture in geriatric population. PATIENTS AND METHODS: We retrospectively reviewed the records from the first 30 days after surgery of patients who were ≥65 years of age and who had a femoral neck fracture treated with surgery between January 2018 and December 2018 at the Honghui Hospital, Xi'an Jiaotong University. Patients were divided into two groups based on whether they did or did not experience POP, and their clinical characteristics were compared. Binomial logistic regression was used to identify potential risk factors of POP by analysing demographic factors, preoperative comorbidities, laboratory results, and surgical factors. RESULTS: A total of 720 patients were included in the analysis, and 54 patients experienced POP. The incidence of POP after surgical treatment for a femoral neck fracture in this geriatric population was 7.5%. In addition, patients with POP had significantly longer hospital stays than patients without POP. The binary logistic regression analysis revealed that preoperative hypoalbuminaemia [odds ratio =5.187, 95% confidence interval (CI): 2.561-10.506, P<0.0001], COPD (OR =3.819, 95% CI: 1.247-11.701, P=0.019), prior stroke (OR =3.107, 95% CI: 1.470-6.568, P=0.003) and the time from injury to surgery (OR =1.076, 95% CI: 1.034-1.119, P<0.0001) were predominant and independent risk factors associated with POP after femoral neck fracture in this geriatric population. CONCLUSION: The current study revealed that among a geriatric population admitted for femoral neck fracture surgery, preoperative hypoalbuminaemia was a predictor of POP, followed by COPD, prior stroke and the time from injury to surgery. Thus, patients who undergo femoral neck fracture surgery and have preoperative hypoalbuminaemia should receive additional monitoring and perioperative care.

CTLA-4 regulates T follicular regulatory cell differentiation and participates in intestinal damage caused by spontaneous autoimmunity.

Cytotoxic T lymphocyte-associated protein 4 (CTLA-4) is a co-inhibitory molecule expressed by T cells and is required for immune regulation and inflammation prevention. In clinical patients, the CTLA-4 mutation causes spontaneous immune-related early-onset Crohn's disease; however, its potential mechanism is still unknown. In the current study, we found that defects in CTLA-4 in CD4 cells lead to limited differentiation of T follicular regulatory (Tfr) cells and relatively increased T follicular helper (Tfh) cells and spontaneous B cell germinal centres (GCs) responses that trigger the accumulation of autoantibodies in intestinal epithelial cells. In addition, the deficiency of Tfr cells caused by defects in CTLA-4 causes these cells to lose their function of inhibiting the non-specific immune response produced during the specific humoural immune response induced by MCMV (mouse cytomegalovirus), resulting in acute intestinal injury and death in mice. The lack of Tfr cells may be responsible for the immunosuppressive disorder of inflammatory bowel disease caused by CTLA-4 deficiency. In conclusion, we verified that CTLA-4 may be required for Tfr cell differentiation and production. Tfr cells inhibit B cell responses and prevent humoural autoimmune-mediated intestinal damage by regulating Tfh-dependent GC responses.

Faecal microRNA as a biomarker of the activity and prognosis of inflammatory bowel diseases.

Reasons underlying the individual differences in the clinical manifestations of inflammatory bowel diseases (IBD) and the mechanism by which the host screens the intestinal microbiota remain unclear. The presence of miRNA in faeces might be a potential clue into differences in gut microbiota among these patients. In this study, we analysed the differences in miRNA levels in faecal samples from 117 patients diagnosed with IBD. There was a significant difference in faecal miRNAs between healthy subjects and those with inactive IBD. Further analysis showed that some miRNAs might indicate the severity of IBD activity and prognosis. Sequencing analysis of the 16S RNA V4 region in faecal microbiota in these IBD patients revealed significant differences in the phylogenetic architecture between subjects with active or inactive IBD and between IBD patients and healthy subjects. Finally, in vitro studies showed that these differentially expressed miRNAs have different effects on the proliferative activity of the intestinal microorganisms Fusobacterium nucleatum (Fn), Escherichia coli (E. coli) and segmental filamentous bacteria (SFB). We observed the dynamic uptake of miRNA by these bacteria using flow cytometry. This study reveals a potential link between faecal miRNA, intestinal microbiota, IBD activity and prognosis.