Booster vaccinations are highly recommended in combating the SARS-CoV-2 Omicron variant and its subvariants. However, the optimal booster vaccination strategies and related immune mechanisms with different prior vaccinations are under-revealed. In this study, we systematically evaluated the immune responses in mice and hamsters with different prime-boost regimens before their protective efficacies against Omicron were detected. We found that boosting with Ad5-nCoV, S_WT-2P or S_Omicron-6P induced significantly higher levels of neutralization activities against Omicron variants than CoronaVac and ZF2001 by eliciting stronger germinal center (GC) responses. Specifically, S_Omicron-6P induced even stronger antibody responses against Omicron variants in CoronaVac and Ad5-nCoV-primed animals than non-Omicron-specific vaccines but with limited differences as compared to Ad5-nCoV and S_WT-2P. In addition, boosting with a specific vaccine has the potential to remodel the existing immune profiles. These findings indicated that adenovirus-vectored vaccines and mRNA vaccines would be more effective than other types of vaccines as booster shots in combating Omicron infections. Moreover, the protective efficacies of the vaccines in booster vaccinations are highly related to GC reactions in secondary lymphatic organs. In summary, these findings provide timely important information on prime-boost regimens and future vaccine design.

Vasopressin is a non-catecholamine agent that induces vasoconstriction via V1 receptors. It is currently regarded as a second-line vasopressor in the treatment of septic shock. According to the Surviving Sepsis Campaign Guidelines for the Management of Sepsis and Septic Shock in Adults,vasopressin is recommended when norepinephrine doses reach 0.25–0.50 μg/（kg·min）and normal blood pressure cannot be maintained. However,hemodynamic alterations in pediatric septic shock differ significantly from those observed in adults,and there is currently insufficient evidence to support the use of vasopressin in pediatric septic shock. This review,in conjunction with recent clinical research data,explored the optimal timing of initiation,methods of administration,and clinical evaluation criteria for vasopressin in septic shock,aiming to provide valuable references for the optimization of septic shock management.

Critically ill with capillary leakage syndrome（CLS）presents with damaged vascular endothelial cells with glycocalyx degraded,which increases vascular permeability,and leads to the protein-rich fluid from the intravascular extravasate into the interstitial space.CLS can concomitant symptoms of hypovolemia and fluid overload.Fluid therapy is the most critical element in the treatment of CLS,but still lack of sufficient evidence to guide the choice of fluid management.Based on accurately hemodynamic monitoring,balanced salt or crystalloid + albumin or fresh frozen plasma may be input to ensure effective circulating blood volume.Albumin or fresh frozen plasma is particularly suitable for CLS patients failed to respond to crystalloids during the leakage period.In the later stage of leakage,conservative fluid management with “de-resuscitation”strategy was mainly used with diuretic and hemofiltration (renal replacement therapy/continuous renal replacement therapy) for attenuating fluid overload.Steroids and ulinastatin may be effective in CLS caused by sepsis.

Objective To observe the value of portal venous phase CT radiomics model based on machine learning(ML)for predicting postoperative complications of hepatic alveolar echinococcosis(HAE).Methods Totally 265 HAE patients were retrospectively enrolled and randomly divided into training set(n=185,including 106 cases with postoperative complications)and validation set(n=80,including 40 cases with postoperative complications)at a ratio of 7∶3.Based on portal venous phase CT images,HAE lesions were segmented,and radiomics features were extracted and screened.Totally 5 ML algorithms were used to construct models,and their performance for predicting postoperative complications were compared.Results Among 5 ML radiomics models,support vector machine(SVM)model had the best overall performance for predicting postoperative complications of HAE in both training and validation sets.DeLong test showed that in training set,the area under the curve(AUC)of SVM model was significantly higher than that of logistic regression(LR),K-nearest neighbor(KNN)and multilayer perceptron(MLP)models(all P＜0.001),while in validation set,the AUC of SVM model was significantly higher than that of adaptive boosting(AdaBoost)model(P=0.007).Decision curve analysis indicated that SVM model had the highest clinical net benefit.Conclusion Portal venous phase CT radiomics model based on ML algorithms,especially SVM algorithm,could effectively predict postoperative complications of HAE.

Objective:To compare the clinical features of severe Mycoplasma pneumoniae pneumonia (SMPP) in pediatric intensive care units (PICU) before and after the COVID-19 pandemic.Methods:A retrospective study was conducted in the PICU of Shanghai Children's Hospital. Clinical and laboratory data were collected from medical records of SMPP patients admitted to the PICU before (January to December 2019) and after (March 2023 to February 2024) the COVID-19 pandemic. Patients admitted in 2019 were categorized as the pre-COVID-19 group, while those admitted in 2023-2024 were classified as the post-COVID-19 group.Results:A total of 287 children with SMPP were included, comprising 155 males and 132 females. The pre-pandemic group consisted of 180 cases, while the post-pandemic group had 107 cases. Macrolide-resistant Mycoplasma pneumoniae (MRMP) was detected in 270 cases (94.1%), with no significant difference in MRMP prevalence between the two groups [101 cases (94.4%) vs. 169 cases (93.9%), Z= 0.031, P = 0.861]. The median age of the post-pandemic group was higher than that of the pre-pandemic group [72 (42, 108) months vs. 42 (24, 68) months, Z= 6.438, P < 0.001].Comparisons of complications between the post-pandemic and pre-pandemic groups were as follows: pleural effusion [20 cases (18.7%) vs. 81 cases (45.0%), χ2=20.365, P< 0.001], shock [4 cases (3.7%) vs. 79 cases (43.9%), χ2=52.628, P< 0.001], gastrointestinal dysfunction [2 cases (1.9%) vs. 24 cases (13.3%), χ 2=9.359, P=0.002], liver dysfunction [9 cases (8.4%) vs. 46 cases (25.6%), χ2=12.733, P< 0.001], and renal injury [0 cases vs. 10 cases (5.6%), P=0.015].There was no significant difference in the incidence of respiratory failure [102 cases (95.3%) vs. 172 cases (95.6%), χ2=0.008, P=0.928]. However, the number of cases requiring high-flow oxygen therapy and mechanical ventilation was significantly lower in the post-pandemic group compared to the pre-pandemic group [14 cases (13.3%) vs. 48 cases (26.7%), 21 cases (20.3%) vs. 122 cases (67.8%), all P<0.05].The time from symptom onset to the initiation of tetracycline/quinolone therapy was shorter in the post-pandemic group compared to the pre-pandemic group [7 (3, 10) days vs. 9 (6.3, 11) days, χ2=-3.565, P< 0.001]. The proportion of patients who had already received tetracycline/quinolone therapy before admission to the PICU was significantly higher in the post-pandemic group compared to the pre-pandemic group [25 cases (23.4%) vs. 2 cases (1.1%), χ 2=10.009, P=0.002].Both the total hospital stay and PICU stay were shorter in the post-pandemic group compared to the pre-pandemic group [10.0 (8.0, 14.0) days vs. 15.5 (12.0, 22.0) days, 5 (3.0, 8.0) days vs. 7.0 (5.0, 10.0) days, all P=0.000]. All 7 deaths occurred in the pre-pandemic group, including 5 cases with co-infections and 2 cases with underlying diseases. Conclusions:In the post-COVID-19 era, SMPP cases in the PICU were predominantly observed in children over 5 years old, with a lower incidence of shock, gastrointestinal disorders, liver injury, and kidney injury compared to the pre-pandemic period. Patients with macrolide-resistant Mycoplasma pneumoniae who received timely treatment with tetracycline/quinolones exhibited favorable outcomes.

Objective To explore the effects and mechanism of Shengxian Yixin Granules in treating ventricular remodeling in rats with myocardial infarction based on the PI3K/AKT signaling pathway.Methods A total of 60 SD rats were randomly selected six rats as the control group,and the remaining 54 rats were used as the modeling group.Sham-operation and left anterior descending coronary artery ligation were performed respectively.The modeled rats were divided into model group,Shengxian Yixin Granules group,740Y-P group and Shengxian Yixin Granules+740Y-P group,and were given corresponding intervention for 28 days.Left ventricular ejection fraction(LVEF)and left ventricular fractional shortening(LVFS)were measured by echocardiography,and left ventricular hypertrophy index was calculated,the myocardial morphology was observed by HE and Masson staining,and the protein expressions of p-PI3K,PI3K,p-AKT and AKT were detected by Western blot,RT-qPCR was used to detect the mRNA expressions of type Ⅰ collagen(Col1)and type Ⅲ collagen(Col3),and ELISA was used to detect the contents of serum cardiac troponin T(cTnT),creatine kinase-MB(CK-MB),Col1 and Col3.Results Compared with the control group,the LVEF and LVFS in the model group significantly decreased(P<0.01),the left ventricular hypertrophy index increased(P<0.01);myocardial cells were arranged disorderly,some cells were necrotic,ruptured and their nuclei were dissolved,with obvious neutrophil infiltration,the collagen fiber significantly increased,the protein expressions of p-PI3K and p-AKT in myocardial tissue significantly increased(P<0.05),and the mRNA expression of Col1 and Col3 significantly increased(P<0.01);the contents of serum cTnT,CK-MB,Col1 and Col3 significantly increased(P<0.05,P<0.01).Compared with the model group,the LVEF and LVFS in Shengxian Yixin Granules group significantly improved(P<0.05,P<0.01),and left ventricular hypertrophy index decreased(P<0.05);myocardial necrosis,neutrophil infiltration and collagen fiber deposition were reduced,the protein expressions of p-PI3K and p-AKT in myocardial tissue significantly decreased(P<0.05),and the mRNA expressions of Col1 and Col3 significantly decreased(P<0.01);the contents of serum cTnT,CK-MB,Col1 and Col3 significantly decreased(P<0.05,P<0.01).LVEF and LVFS in 740Y-P group significantly decreased(P<0.01),and left ventricular hypertrophy index increased(P<0.05);a large number of myocardial cells were necrotic and ruptured,fibers were torn obviously,and many scar tissues were formed,the protein expressions of p-PI3K and p-AKT in myocardial tissue significantly increased(P<0.05),the mRNA expressions of Col1 and Col3 significantly increased(P<0.01);the contents of serum cTnT,CK-MB,Col1 and Col3 significantly increased(P<0.05,P<0.01).Shengxian Yixin Granules+740Y-P could improve the damage of 740Y-P to the heart.Conclusion Shengxian Yixin Granules can improve ventricular remodeling in rats with heart failure,reduce myocardial fibrosis,and improve cardiac function through the PI3K/AKT signaling pathway.

Objective To observe the value of portal venous phase CT radiomics model based on machine learning(ML)for predicting postoperative complications of hepatic alveolar echinococcosis(HAE).Methods Totally 265 HAE patients were retrospectively enrolled and randomly divided into training set(n=185,including 106 cases with postoperative complications)and validation set(n=80,including 40 cases with postoperative complications)at a ratio of 7∶3.Based on portal venous phase CT images,HAE lesions were segmented,and radiomics features were extracted and screened.Totally 5 ML algorithms were used to construct models,and their performance for predicting postoperative complications were compared.Results Among 5 ML radiomics models,support vector machine(SVM)model had the best overall performance for predicting postoperative complications of HAE in both training and validation sets.DeLong test showed that in training set,the area under the curve(AUC)of SVM model was significantly higher than that of logistic regression(LR),K-nearest neighbor(KNN)and multilayer perceptron(MLP)models(all P＜0.001),while in validation set,the AUC of SVM model was significantly higher than that of adaptive boosting(AdaBoost)model(P=0.007).Decision curve analysis indicated that SVM model had the highest clinical net benefit.Conclusion Portal venous phase CT radiomics model based on ML algorithms,especially SVM algorithm,could effectively predict postoperative complications of HAE.

Objective This study aimed to investigate the antimicrobial resistance profiles of bacterial strains isolated from pediatric intensive care units(PICU)in China for better antimicrobial therapy.Methods Clinical isolates were collected from 17 institutions,including tertiary care children's hospitals and pediatric department of tertiary general hospitals in China from January 1,2020 to December 31,2022.Antimicrobial susceptibility testing was carried out according to a unified protocol using Kirby-Bauer method or automated systems.Results were interpreted according to the breakpoints released by the Clinical and Laboratory Standards Institute(CLSI)in 2020.Results A total of 10 688 isolates were collected,including gram-positive organisms(39.2％)and gram-negative organisms(60.8％).The top three organisms were S.aureus(13.6％,1 453/10 688),A.baumannii(10.0％,1 067/10 688),and coagulase-negative Staphylococcus(9.9％,1 058/10 688).Multi-drug resistant organisms(MDROs)were very common in children.The prevalence of methicillin-resistant Staphylococcus aureus(MRSA),carbapenem-resistant Enterobacterales(CRE),carbapenem-resistant E.coli,carbapenem-resistant K.pneumoniae(CRKP),carbapenem-resistant A.baumannii(CRAB),and carbapenem-resistant P.aeruginosa(CRPA)was 41.1％,19.4％,8.8％,30.9％,67.4％,and 28.8％,respectively.Overall,more than 50％of Enterobacteriales isolates were resistant to cephalosporins,while nearly 25％of Enterobacteriales isolates were resistant to carbapenems.MDROs were highly resistant to commonly used antibiotics.More than 80％of CRE and CRAB strains were resistant to all beta-lactam antibiotics.CRE and CRAB showed low resistance rates to tigecycline and polymyxin.CRPA showed lower resistance rates to piperacillin,beta-lactamase inhibitor combinations than the resistance rates to third and fourth generation cephalosporins.All of the Staphylococcus and Enterococcus isolates were susceptible to vancomycin and tigecycline.None of PRSP strains isolated from meningitis and nonmeningitis samples were resistant to rifampicin,vancomycin,or linezolid.The prevalence of β-lactamase-negative ampicillin-resistant(BLNAR)strains was 43.3％in Haemophilus influenzae.Conclusions MDROs were prevalent in PICU.It is necessary to establish an effective multidisciplinary team(MDT)to control the antimicrobial resistance.

The standard therapy bundle for septic shock includes antibiotics,fluid resuscitation,vasopressors and inotropes. Given the high mortality rates associated with septic shock,there is an ongoing need for active research into potential therapies to improve outcomes. Venoarterial extracorporeal membrane oxygenation (VA-ECMO) is an acceptable and beneficial therapeutic modality for patients who fail conventional management and have decreased left ventricular ejection fraction. Up to now,the benefits of ECMO in pediatric sepsis remain unclear. Whether ECMO is the rescue therapy or is appropriately utilized in the early stage (window forward) remains controversial. At the present stage,it is necessary to strictly screen patients and make individualized decisions based on dynamic hemodynamic monitoring and biomarkers.

Objective:To explore the risk factors of deaths caused by influenza-associated encephalopathy (IAE) in children.Methods:A case control study was conducted.The clinical data (including baseline fata, organ function indices, inflammatory factors, imaging data, treatment, and outcomes) of IAE children hospitalized in the pediatric intensive care unit (PICU) of Shanghai Children′s Hospital, School of Medicine, Shanghai Jiao Tong University from January 2020 to December 2023 were retrospectively analyzed.The children were divided into a survival group and a death group.The Logistic regression and receiver operating characteristic (ROC) curve were used to analyze the risk factors of death in IAE children.Results:A total of 46 cases were included, with an onset age of 74.8(46.0, 92.5) months.The main cause of IAE was influenza A virus infection, which was detected in 45 cases(97.8%), and 32 cases (69.6%) of them had H3N2.One child (2.2%) was infected by influenza B virus.Eight children died, showing a mortality of 17.4%.There was significant difference in Glasgow Coma Scale between the survival and death groups when they were admitted into the PICU [10 (9, 11) points vs.3 (3, 5) points] ( Z=-4.510, P<0.05).All patients in the death group had multiple organ dysfunction syndrome, respiratory failure and circulatory system failure.Serum procalcitonin (PCT)[15.7 (3.3, 37.4) μg/L], interleukin-6 (IL-6)[1 039.1 (319.3, 2 884.3) ng/L], and cerebrospinal fluid protein(CSFP)[13 050.0 (5 865.0, 21 100.0) mg/L] in the death group compared with those in the survival group [0.2 (0.1, 0.8) μg/L, 15.5 (7.9, 44.8) ng/L, 227.0 (190.0, 332.0) mg/L]were highly increased ( Z=-3.364, -4.088, -3.757, all P<0.001).Logistic regression analysis showed that PCT ( OR=0.660, P<0.05), IL-6 ( OR=1.014, P<0.05) and CSFP ( OR=1.001, P<0.05) were risk factors of death in IAE.The areas under the ROC curve for these three factors were 0.88 (95% CI: 0.77-0.97), 0.96 (95% CI: 0.86-1.00) and 0.93 (95% CI: 0.76-1.00), respectively.When a cutoff value of 2.50 μg/L, 269.67 ng/L and 5 240.00 mg/L was taken, PCT achieved a sensitivity of 0.875 and a specificity of 0.816, IL-6 achieved a sensitivity of 0.875 and specificity of 0.974, and CSFP achieved a sensitivity of 0.875 and specificity of 0.974, respectively. Conclusions:High levels of serum PCT, IL-6 and CSFP at PICU admission are risk factors of poor prognosis in children with IAE.