Objective To evaluate the impact of different dosing times of doxycycline(DOX)on children with macrolide-resistant Mycoplasma pneumoniae pneumonia(MR-MPP).Methods Clinical data of children diagnosed with MR-MPP at Hangzhou Children's Hospital from January 2022 to December 2023 were analyzed.Children were divided into three groups based on treatment regimens:the doxycycline(DOX)group,the intravenous azithromycin converted to oral DOX(ATD)group,and the intravenous azithromycin alone(AZI)group..The ATD group was further divided into ATD1 group(＜3 days)and ATD2 group(＞3 days)according to the duration of azithromycin treatment.Clinical symptoms of each group were compared,and propensity score matching(PSM)analysis was used for adjustment.Results A total of 156 children with MR-MPP were included in the study,with 25 in the DOX group,85 in the ATD group,and 46 in the AZI group.Compared with the ATD and AZI groups,the DOX group had a shorter hospital stay and fever duration,higher chest radiograph improvement rate,and lower glucocorticoid usage rate(P＜0.05).The DOX group and ATD1 group had lower hospital stays,post-treatment fever durations,and glucocorticoid usage rates than the ATD2 group,and higher 96-hour fever resolution rates and chest X-ray improvement rates than the ATD2 group(P＜0.05).The DOX group had a higher fever resolution rate within 72 hours compared to the ATD1 and ATD2 groups(P＜0.05).PSM analysis showed that the DOX-ATD1 group had a lower hospital stay,post-treatment fever duration,and glucocorticoid usage rate than the ATD2 group,and a higher 72-hour fever resolution rate than the ATD2 group(all P＜0.05).No adverse reactions related to DOX were observed during the treatment period.Conclusion Early oral administration of DOX within 72 hours can significantly improve the clinical efficacy in children with MR-MPP.

Purpose To evaluate the feasibility of cardiac magnetic resonance fractal analysis in evaluating left ventricular trabecular complexity in hypertrophic cardiomyopathy(HCM),and to study the degree of left ventricular trabecular complexity in HCM and the relationship between excessive trabecular complexity and cardiac function.Materials and Methods From August 2020 to December 2022,a total of 80 patients with HCM from the Second Affiliated Hospital of Nanchang University were retrospectively analyzed.Additionally,80 healthy volunteers were recruited as the control group.Left ventricular functional parameters and fractal dimension(FD)of left ventricular trabecular myocardium were measured.The differences of mean global FD,max basal FD and max apical FD were compared between the HCM group and the control group,the correlation between FDs and cardiac function parameters was evaluated.The diagnostic efficiency of mean global FD,max apical FD and max basal FD was analyzed via receiver operating characteristic curve.Results The mean global FD of HCM group was significantly higher than that of normal group,and the difference was statistically significant(1.303±0.047 vs.1.229±0.026;t=-12.387,P<0.001).Mean global FD showed the best performance in differentiating HCM from normal control group.The optimal cut-off value for the diagnosis of HCM was 1.251,with the area under curve of 0.933(95%CI 0.896-0.969).Mean global FD was positively correlated with maximum wall thickness and left ventricular mass index(r=0.686,0.687,P<0.001),and max apical FD was positively correlated with left ventricular ejection fraction(r=0.520,P<0.001).Conclusion The FD obtained by cardiac magnetic resonance fractal analysis technique is reproducible and has definite value in the diagnosis of HCM,with association with the structure and function of left heart.