Objective:To explore the clinical characteristics, diagnosis, treatment, and follow-up of multisystem inflammatory syndrome in children (MIS-C) related to SARS-CoV-2 Omicron variant infection.Methods:A retrospective analysis was conducted on clinical data of 11 children with MIS-C, who were admitted to the Department of Pediatrics of Peking University First Hospital from December 2022 to January 2023. Clinical characteristics, treatment, and follow-up of MIS-C were summarized in this study.Results:The 11 cases contained 7 boys and 4 girls, with an age of 4.4 (2.0, 5.5) years on admission. All the patients had fever, with a duration of 7(5, 9) days. Other clinical manifestations included rash in 7 cases, conjunctival hyperemia in 5 cases, red lips and raspberry tongue in 3 cases, lymphadenopathy in 3 cases, and swollen fingers and toes in 2 cases. There were 8 cases of digestive symptoms, 8 cases of respiratory symptoms, and 3 cases of nervous system symptoms. Eight patients had multi-system injuries, and one of them had shock presentation. All 11 patients were infected with SARS-CoV-2 Omicron BF.7 variant. The laboratory examination results showed that all cases had elevated inflammatory indicators, abnormal coagulation function and myocardial damage. Six patients had elevated white blood cell counts, 5 cases had liver function abnormalities, 3 cases had kidney function abnormalities, and 8 cases had coronary artery involvement. All 11 patients received anti-infection treatment, of which 3 cases received only 2 g/kg intravenous immunoglobulin (IVIG), while the remaining 8 cases received a combination of IVIG and 2 mg/(kg·d) methylprednisolone. Among the 8 cases with coronary artery disease, 6 cases received low molecular weight heparin anticoagulation therapy. All patients were followed up in 2 weeks after being discharged, and their inflammatory markers had returned to normal by that time. The 8 cases with coronary artery disease and 3 cases with pneumonia showed significant improvement or back to normal at the 4-week follow-up. All patients had no new complications or comorbidities during follow-up of more than 3 months.Conclusions:MIS-C may present with Kawasaki disease-like symptoms, with or without gastrointestinal, neurological, or respiratory symptoms. Elevated inflammatory markers, abnormal coagulation function, and cardiac injury contribute to the diagnosis of MIS-C. IVIG and methylprednisolone were the primary treatments for MIS-C, and a favorable short-term prognosis was observed during a follow-up period of more than 3 months.

Objective:To explore the clinical efficacy of a retrograde pubic ramus intramedullary nail (RPRIN) in the treatment of anterior pelvic ring fractures.Methods:A retrospective study was conducted to analyze the 14 patients with anterior pelvic ring fracture who had been treated and followed up at Department of Traumatic Surgery, Tongji Hospital From June 2020 to February 2021. There were 10 males and 4 females with an age of (44.8±12.5) years. By the AO/OTA classification for pelvic fractures, 5 cases were type 61-A, 4 cases 61-B, and 5 cases type 61-C; by the Nakatani classification, 1 case belonged to unilateral zone Ⅰ fracture, 5 cases to unilateral zone Ⅱ fracture, 2 cases to unilateral zone Ⅲ fracture, 3 cases to right zone Ⅱ and left zone Ⅲ fracture, 2 cases to zone Ⅲ fracture on both left and right sides, and 1 case to zone Ⅱ fracture on both sides. The time from injury to operation was (7.8±1.8) days. All the anterior pelvic ring fractures were fixated with a RPRIN. The time and fluoroscopic frequency for placement of every single RPRIN, quality of fracture reduction, and pelvic function and incidence of postoperative complications at the last follow-up were recorded.Results:A total of 18 RPRINs were placed in the 14 patients. For placement of each RPRIN, the time was (35.9±8.6) min, and the fluoroscopic frequency (22.8±1.9) times. No complications such as infection occurred at any surgical incision after RPRIN placement. According to the Matta scoring, the quality of postoperative fracture reduction was assessed as excellent in 7 cases, as good in 5 cases and as fair in 2 cases. The 14 patients were followed up for (18.1+1.5) months. Their X-ray and CT images of the pelvis at the last follow-up showed that the fractures healed well and the intramedullary nails were placed in the cortical bone of the anterior ring of the pelvis. According to the Majeed scoring at the last follow-up, the pelvic function was assessed as excellent in 10 cases, as good in 3 cases and as fair in 1 case. One patient reported discomfort during squatting 2 months after operation but the symptom improved 3 months later without any special treatment. No patient experienced such complications as displacement or slippage of RPRIN, or pain at the insertion site.Conclusion:RPRIN is effective in the treatment of anterior pelvic ring fractures, showing advantages of small surgical incision, limited intraoperative fluoroscopy and short operation time.

Objective To observe the electrophysiological characteristics of the inward current of cardiomyocyte-like cells derived from rat bone marrow mesenchymal stem cells (MSCs). Methods Bone marrow specimens was extracted from SD rats aged 1 month. MSCs were isolated by gradient centrifugation and obtained by adherence culture. The second-passage MSCs were treated with 10 ?mol/L 5-azacytidine and incubated for 24 h. After 4 weeks, cardiomyocyte-like cells were identified by immunocytochemical staining technique, then used to detect the inward current with the whole-cell patch-clamp technique, which results were compared with the normal cardiomyocytes and the MSCs without induction. Results Some cardiomyocyte-like cells were stained positive for troponin T, and the quickly activated and inactivated inward currents were elicited 4 weeks after 5-aza cytidine treatment. The inward currents of cardiomyocyte-like cells recorded in the same square pulse were weaker than that of the normal cardiomyocytes, and the I-V curve of cardiomyocyte-like cells was right-shifted. Conclusion After treated with 5-azacytidine, MSCs differentiate into cardiomyocyte-like cells which express the excitable inward current.