Objective:To explore the application of COVID-19-specific IgG antibody in identifying epidemic Omicron BA.5 strain infection.Method:Omicron BF.7/BA.5 naturally infected population, healthy population vaccinated with the COVID-19 vaccine, and Omicron BF.7/BA.5 breakthrough cases were enrolled into this study. The serum WT-S-IgG and BA.5-S-IgG were detected by indirect ELISA, and the serum-specific IgG antibody levels of different populations were compared. The application value of the two antibody titers and the ratio of the two antibodies in identifying Omicron BA.5 epidemic strain infection were explored by the ROC curve, aiming to provide technical support for pathogen diagnosis.Results:The antibody titers of WT-S-IgG and BA.5-S-IgG in the breakthrough cases were higher than those in the naturally infected population and the healthy population ( P<0.05). The area under the curve (AUC) of WT-S-IgG and BA.5-S-IgG in identifying epidemic Omicron BA.5 strain infection was 0.947 and 0.961, respectively. The AUC of BA.5-S-IgG and WT-S-IgG antibody titer ratio was 0.873. When the antibody titer ratio was 0.855, the sensitivity and specificity were 80.00% and 90.00%, respectively. According to the interval since the last infection, the AUC of the ratio of BA.5-S-IgG to WT-S-IgG antibody titer to identify the infection of epidemic strains less than 30 days and more than 30 days was 0.887 and 0.863, respectively, and the sensitivity and specificity were both above 80%. Conclusion:Both BA.5-S-IgG and WT-S-IgG, as well as the combination of these two antibodies, are of high value in the identification of epidemic strains.

Objective:To explore the application of COVID-19-specific IgG antibody in identifying epidemic Omicron BA.5 strain infection.Method:Omicron BF.7/BA.5 naturally infected population, healthy population vaccinated with the COVID-19 vaccine, and Omicron BF.7/BA.5 breakthrough cases were enrolled into this study. The serum WT-S-IgG and BA.5-S-IgG were detected by indirect ELISA, and the serum-specific IgG antibody levels of different populations were compared. The application value of the two antibody titers and the ratio of the two antibodies in identifying Omicron BA.5 epidemic strain infection were explored by the ROC curve, aiming to provide technical support for pathogen diagnosis.Results:The antibody titers of WT-S-IgG and BA.5-S-IgG in the breakthrough cases were higher than those in the naturally infected population and the healthy population ( P<0.05). The area under the curve (AUC) of WT-S-IgG and BA.5-S-IgG in identifying epidemic Omicron BA.5 strain infection was 0.947 and 0.961, respectively. The AUC of BA.5-S-IgG and WT-S-IgG antibody titer ratio was 0.873. When the antibody titer ratio was 0.855, the sensitivity and specificity were 80.00% and 90.00%, respectively. According to the interval since the last infection, the AUC of the ratio of BA.5-S-IgG to WT-S-IgG antibody titer to identify the infection of epidemic strains less than 30 days and more than 30 days was 0.887 and 0.863, respectively, and the sensitivity and specificity were both above 80%. Conclusion:Both BA.5-S-IgG and WT-S-IgG, as well as the combination of these two antibodies, are of high value in the identification of epidemic strains.

Objective:We evaluated frailty in elderly hospitalized patients with atrial fibrillation and analyzed the relevance, consistency, and diagnostic power of different frailty tools.Methods:From September 2018 to April 2019, a total of 197 elderly patients with atrial fibrillation aged ≥ 65 years in Beijing Hospital, Chinese PLA General Hospital, and Beijing Tsinghua Changgung Hospital were prospectively enrolled.Five frailty tools, including the clinical frailty scale(CFS), FRAIL scale(FRAIL), Fried frailty phenotype(Fried), Edmonton frail scale(EFS), and comprehensive geriatric assessment-frailty index(CGA-FI), were used for frailty assessment.Results:A total of 197 hospitalized elderly patients with atrial fibrillation were enrolled, with an average age of(77.5±7.1)years old(57.4% male). The prevalence of frailty, according to the five frailty tools, were 25.4%(FRAIL), 27.9%(EFS), 34.5%(Fried), 40.6%(CFS), and 42.6%(CGA-FI), respectively.CFS had a good correlation(correlation coefficient 0.80)and and consistency(Kappa value 0.71, 95% CI 0.61~0.81)with CGA-FI.The combined frailty index was used as the gold standard for frailty diagnosis.The results showed that CFS and CGA-FI had high diagnostic sensitivity(95.9 % and 98.0 %, respectively)and specificity(77.7 % and 75.7 %, respectively). Conclusions:Frailty is common in elderly hospitalized patients with atrial fibrillation, showing multidimensional features, and physical weakness is not prominet.CFS and CGA-FI are recommended for the assessment of frailty in patients with atrial fibrillation, which had good correlation and consistency.

Renal allograft biopsy (biopsy) remains the "gold standard" for the diagnosis of renal dysfunction after kidney transplantation. Puncture biopsy after kidney transplantation could be divided into indicative biopsy and protocol biopsy according to renal function of the patients. Indicative biopsy is mainly applied to diagnose postoperative complications of kidney transplantation, evaluate the severity of disease and guide subsequent treatment. Protocol biopsy is primarily employed to regular monitor renal allograft function of kidney transplant recipients and exclude subclinical rejection and other complications. Due to the willingness of patients and other reasons, protocol biopsy has not been widely applied in China. Currently, indicative biopsy is the main biopsy pattern. At present, the indications of puncture of indicative biopsy, the timing and necessity of puncture of protocol biopsy remain controversial. In this article, the classification of puncture biopsy after kidney transplantation and research progress on tissue biomarkers based on biopsy were reviewed, aiming to assist clinical diagnosis and targeted treatment of complications after kidney transplantation and provide reference for further improving the survival of renal allografts and recipients.

Kidney transplantation is more efficacious compared with other organ transplantations. Nevertheless, postoperative complications, such as renal ischemia-reperfusion injury (IRI), severely affect the survival rate and quality of life of recipients. How to mitigate the IRI of renal allografts has become one of the key topics in the field of kidney transplantation. At present, ischemic preconditioning enables renal allografts to adapt to ischemia, which is one of the effective methods to prevent the progression of IRI. However, the underlying mechanism remains elusive. In this article, the application of ischemic preconditioning in IRI, the regulation mechanism of ischemic preconditioning on the IRI of renal allografts at the cellular level and intracellular signaling pathway, and clinical application value and prospect of ischemic preconditioning were reviewed, aiming to provide reference for alleviating the IRI of renal allografts, enhancing the survival rate of the recipients and renal allografts and improving the quality of life of recipients.

Objective To investigate the role and mechanism of growth differentiation factor (GDF) 15 in ischemia-reperfusion injury (IRI) during kidney transplantation. Methods Nine wild type donor mice and 9 wild type recipient mice were selected. The renal graft of 3 recipient mice were harvested at 4, 24 and 72 h after transplantation. GDF family transcriptome analysis was carried out, and the expression of GDF15 in renal tissues of each group were detected. Five wild type donor mice, 5 GDF15 knockout donor mice and 10 wild type recipient mice were selected. According to the experimental scheme, the mice were divided into wild type sham operation group, wild type transplantation group, GDF15 knockout sham operation group and GDF15 knockout transplantation group. Serum and renal tissue samples were extracted 72 h after transplantation. The renal function, renal tubular injury, inflammatory cell infiltration, inflammatory factors, Toll-like receptor 4 (TLR4) and nuclear factor (NF)-κB expression level were compared in each group. Nine wild type donor mice, 9 GDF15 knockout donor mice and 18 wild type recipient mice were selected. According to the experimental scheme, the mice were divided into wild type transplantation group and GDF15 knockout transplantation group, and the survival rate of two group after kidney transplantation was observed. Results Transcriptome sequencing of renal graft tissues indicated that GDF15 was the most up-regulated GDF family gene, which was mainly expressed in renal tubules. Compared with the sham operation group, the renal function of mice was declined in the transplantation group. Compared with the wild type transplantation group, the serum creatinine and blood urea nitrogen levels of mice were significantly up-regulated in the GDF15-knockout transplantation group (both P < 0.05). The 1-week survival rate of mice was 87.6% in the wild type transplantation group and 41.8% in the GDF15 knockout transplantation group. In the GDF15 knockout transplantation group, the expression level of kidney injury molecule (KIM)-1 was up-regulated, and the renal tubule injury score was increased. In the wild type transplantation group, the renal tubules were dissolved or necrotized, and tubular formation was seen in the extramedullary and cortex area, whereas tubular necrosis and tubular formation were more evident in the GDF15 knockout transplantation group. The expression levels of myeloperoxidase (MPO) and F4/80 were up-regulated in the transplantation group, and the inflammatory cell infiltration was aggravated in the GDF15 knockout transplantation group. Compared with the sham operation group, the expression levels of tumor necrosis factor (TNF)-α, interleukin (IL)-1β and IL-6 in the transplantation group were up-regulated. Compared with the wild type transplantation group, the expression levels of TNF-α, IL-1β and IL-6 were also up-regulated in the GDF15 knockout transplantation group (all P < 0.05). In the transplantation group, the expression levels of TLR4 and NF-κB in the renal graft tissues were higher than those in the sham operation group. In the GDF15 knockout transplantation group, the expression levels of TLR4 and NF-κB in the renal graft tissues were higher compared with those in the wild type transplantation group. Conclusions GDF15 may alleviate the IRI of renal graft probably via inhibiting the TLR4-NF-κB signaling pathway.

Objective:To establish donor liver quality related risk factors for the loss of function of transplanted liver.Methods:The data of donors and recipients of liver transplantation at the Organ Donation and Transplantation Center of the First Affiliated Hospital of Sun Yat-sen University from Nov 2011 to Dec 2018 were analyzed retrospectively. Propensity score matching (PSM) was performed to evaluate and screen the data of donors and recipients, in order to balance the covariates.Results:Of the organ donation, there were 70 males and 20 females , aging (40.6±16.3) years. Of the liver transplantation recipients, there were 70 males and 20 females , aging (41.8±20.3) years. Liver dysfunction after transplantation was significantly correlated with the following variables: the donor's CPR time( t=0.429, P=0.000), 15-minute retention rate of indocyanine green ( χ2=67.151, P=0.000), liver function grading ( χ2=54.154, P=0.000), bullae fatty liver grading ( χ2=8.120, P=0.017), vesicular fatty liver grading ( χ2=16.000, P=0.001), ICU stay time ( χ2=14.900, P=0.001)and serum creatinine level ( χ2=44.685, P=0.000). The donor scoring system was established in our studying. For the 90 organ donation cases, the donated liver quality were classified into four levels,which were of good correspondence to the prognosis of the recipients. Conclusion:This donor scoring system and grading standards established by analyzing the high-risk factors of liver dysfunction after transplantation helps evaluate the quality of donor liver in China.

Objective:To analyze the clinical characteristics and prognostic factors in patients with new-onset acute heart failure (AHF) and acutely decompensated chronic heart failure (ADCHF).Methods:Patients with heart failure (HF) admitted to Beijing Hospital during January 2009 to December 2017 with follow-up records were retrospectively enrolled. According to the duration of heart failure, the patients were divided into new-onset AHF group (duration of HF<1 month) and ADCHF group (duration of HF ≥1 month). Clinical data were collected and endpoint events (all-cause death and cardiovascular death) were recorded. The Kaplan-Meier survival curve and the log-rank method was used to compare survival between different groups. The multivariate Cox regression model was used to analyze the independent risk factors for the end-point events in patients with new-onset AHF and ADCHF.Results:The study enrolled 562 patients,292 (52.0%) with new-onset AHF and 270 (48.0%) with ADCHF. Patients with new-onset AHF were more likely to have coronary heart disease, acute myocardial infarction, higher diastolic blood pressure and higher troponin I levels(χ2=12.999,15.018, t=-2.088, Z=-2.727; all P<0.05). Patients with ADCHF were more likely to have poor cardiac function, atrial fibrillation, larger left ventricle and left atrium diameter, higher proportion of patients with pulmonary hypertension(χ2=16.565, 15.688, t=2.714, 5.029, χ2=15.274; all P<0.05). There were 205 (36.5%) all-cause deaths and 132 (23.5%) cardiovascular deaths during 28 (14, 60) months of follow-up. All-cause mortality rate [33.2%(97/292) vs. 40.0%(108/270), log-rank P=0.010] and cardiovascular mortality rate [18.8%(55/292) vs. 28.5%(77/270), log-rank P=0.001]were significantly lower in patients with new-onset AHF than those in ADCHF group. Multivariate Cox regression analysis showed that low body mass index (BMI), reduced hemoglobin, reduced resting heart rate, enlarged left atrium, and segmental wall motion abnormalities were independent risk factors for poor prognosis in new-onset AHF patients. It was different with ADCHF patients. Conclusion:Patients with new-onset AHF are more likely to have coronary heart disease; and lower BMI, reduced hemoglobin, acute coronary disease are associated with poor prognosis of patients. It is necessary to identify the underlying diseases early and actively standardize treatment to avoid the deterioration of cardiac function and readmission.

Objective:To analyze the incidence and epidemiological characteristics of traumatic spinal cord injury in China in 2018.Methods:Multi-stage stratified cluster sampling was used to randomly select hospitals capable of treating patients with spinal cord injury from 3 regions，9 provinces and 27 cities in China to retrospectively investigate eligible patients with traumatic spinal cord injury admitted in 2018. National and regional incidence rates were calculated. The data of cause of injury，injury level，severity of injury，segment and type of fracture，complications，death and other data were collected by medical record questionnaire，and analyzed according to geographical region，age and gender.Results:Medical records of 4，134 patients were included in this study，with a male-to-female ratio of 2.99∶1. The incidence of traumatic spinal cord injury in China in 2018 was 50.484 / 1 million （95% CI 50.122-50.846）. The highest incidence in the Eastern region was 53.791 / 1 million （95% CI 53.217-54.365）. In the whole country，the main causes of injury were high falls （29.58%），as well as in the Western region （40.68%），while the main causes of injury in the Eastern and Central regions were traffic injuries （31.22%，30.10%）. The main injury level was cervical spinal cord in the whole country （64.49%），and the proportion of cervical spinal cord injury in the Central region was the highest （74.68%），and the proportion of lumbosacral spinal cord injury in the Western region was the highest （32.30%）. The highest proportion of degree of injury was incomplete quadriplegia （55.20%），and the distribution pattern was the same in each region. A total of 65.87% of the patients were complicated with fracture or dislocation，77.95% in the Western region and only 54.77% in the Central region. In the whole country，the head was the main combined injury （37.87%），as well as in the Eastern and Central regions，while the proportion of chest combined injury in the Western region was the highest （38.57%）. A total of 32.90% of the patients were complicated with respiratory complications. There were 23 patients （0.56%） died in hospital，of which 17（73.91%） died of respiratory dysfunction. Conclusions:The Eastern region of China has a high incidence of traumatic spinal cord injury. Other epidemiological features include high fall as the main cause of injury cervical spinal cord injury as the main injury level，incomplete quadriplegia as the main degree of injury，head as the main combined injury，and respiratory complications as the main complication.

Objective: To determine the frequency and extent of left ventricular amyloid deposition in patients aged over 85 years with heart failure and preserved ejection fraction (HFpEF). Methods: A total of 43 patients aged 85 to 100 years old were enrolled in this study based on the autopsy database of Beijing Hospital from February 1, 2003 to October 31, 2016. The frequency and extent of left ventricular amyloid deposition and myocardial fibrosis were determined in left ventricular specimens from patients with antemortem diagnosis of HFpEF without clinically apparent amyloid (n=28) and from control subjects (n=15) post Congo red staining and Masson's trichrome staining. Kappa test was used to evaluate the consistency of the myocardial amyloidosis and fibrosis. Results: The heart weight of the patients in HFpEF group and in control group were similar((452.7±107.7)g vs. (415.0±70.8)g, t=-1.218, P=0.23)). Positive Congo-red staining was found in 24 examples (24/28) in HFpEF group and 5 examples (5/15) in the control group; severe amyloid deposition was found in 7 examples (7/28) in HFpEF group, but not in the control group. Amyloid deposition was more severe in HFpEF group than in control group (χ²=12.205, P<0.01). Masson's trichrome staining evidenced moderate to severe fibrosis in 19 cases (19/28) in HFpEF group and 8 cases (8/15) in control group (χ²=1.019, P=0.35). A consistent evaluation of the degree of myocardial fibrosis and the degree of myocardial amyloid deposition in all selected participants was performed and results showed that these two parameters were not consistent (Kappa value=0.2, P=0.820). Conclusion Amyloid deposition is common in the elderly patients with heart failure and preserved ejection fraction, suggesting that myocardial amyloidosis may be related to the development of HFpEF. There is no significant correlation between myocardial amyloidosis and myocardial fibrosis in this cohort.