Objective:To assess the left ventricular (LV) systolic function in amateur marathoners by two-dimensional speckle tracking echocardiography.Methods:A total of 59 amateur marathon runners were recruited from January 2019 to June 2020 in Hangzhou and were divided into group A (>2-5 years) and group B (>5 years) based on their time of participating in marathon. Thirty-one healthy volunteers were enrolled from Affiliate Hospital of Hangzhou Normal University during the same period as a control group. Conventional echocardiography combined with two-dimensional speckle tracking imaging were applied to all the subjects to obtain interventricular septum diastolic thickness (IVSd), LV posterior wall thickness(PWd), LV end-diastolic diameter (LVEDd), relative wall thickness(RWT) and LV mass(LVM), LV end-diastolic volume(EDV), LV end-systolic volume(ESV) and stroke volume(SV), LV ejection fraction(LVEF), LV global longitudinal strain (GLS), and global circumferential strain (GCS). Pre-marathon, 1 hour and 4th day post-marathon echocardiography were performed in amateur marathon runners.Results:Compared with the control group, group A amateur marathon runners showed significant increases in IVSd, PWd, LVEDd, RWT and LVM(all P<0.05); In addition, the IVSd, PWd, LVEDd, RWT, LVM, EDV, ESV and SV in group B runners were further increased compared to those of group A runners (all P<0.01). The LVEF and pre-marathon GCS showed no statistically significant differences among the three groups (all P>0.05), while the pre-marathon GLS showed a statistically significant difference among the three groups ( P<0.01). Compared with group A runners, the pre-marathon, 1 hour and 4th day post-marathon GLS and 1 hour post-marathon GCS were significantly decreased in group B runners (all P<0.01); In intra-group comparison, 1 hour post-marathon GLS was significantly decreased in relative to pre-marathon and 4th day post-marathon GLS in both group A and B (all P<0.05). One hour post-marathon GCS was significantly decreased compared with pre-marathon GCS in group B ( P<0.05). Conclusions:Amateur runners who have participated in long time marathon have reduced LV longitudinal strains and transient post-marathon decreases in LV systolic function.

Objective To discuss the controversial role of breast milk in late-onset group B Streptococcus (GBS) infections.Methods This study reported a case of recurrent late-onset GBS sepsis with the suspicion of breast milk transmission in an extremely preterm infant born at 22+6 weeks who was treated at the University of Hong Kong-Shenzhen Hospital in September 2016.Literatures about late-onset GBS cases associated with contaminated breast milk were reviewed to investigate whether GBS could be transmitted through breast milk.Results (1) Case report:A breast-fed extremely preterm infant born at 22+6 gestational weeks suffered from GBS sepsis along with meningitis for the first time on 100 d.The mother was negative for rectovaginal GBS screening.Breast milk wasn't tested as no signs of mastitis were found.The neonate recovered from the first GBS sepsis after 14 days of antibiotic treatment,then returned to breastfeeding.On 126 d,GBS sepsis reoccurred in this baby.Fresh breast milk culture yielded GBS which was identical with the GBS strains isolated from the neonatal blood in antimicrobial susceptibility.After recovery from the second episode,the baby was partially breastfed again without further relapses of late-onset GBS sepsis.(2) Literature review:64 cases of late-onset GBS infections that transmitted via breast milk were retrieved from PubMed,while no Chinese cases had been reported.Clinical data of the 65 cases (including this case) were reviewed and the results revealed that contaminated breast milk was associated with late-onset GBS infections.The reported relapse rate of GBS infections transmitted via breast milk was 25％ for two episodes and 7％ for three episodes.Conclusions GBS contaminated breast milk could potentially cause late-onset GBS sepsis in infants and further studies are required to identify the underlying mechanisms.

Objective:To assess the left ventricular(LV) structure and systolic function in amateur marathon runners using real-time three-dimensional speckle tracking echocardiography(3D-STE) and analyze its correlation with the running volume.Methods:A total of 84 amateur marathon runners were recruited between January 2019 and October 2021 in Hangzhou and were divided into short-term (ST) group(≤6 months) and more extended-term(MET) group(>6 months–2 years) based on their time of participating in the marathon. Thirty-nine healthy volunteers were enrolled from the Affiliated Hospital of Hangzhou Normal University during the same period as a control group. The running volume of ST and MET runners were recorded, LV end-diastolic volume(EDV), end-systolic volume(ESV), LV mass(LVM), LV ejection fraction(LVEF), LV global longitudinal strain(GLS), global circumferential strain(GCS), global radial strain(GRS), global area strain (GAS), twist, and torsion were measured by conventional echocardiography and 3D-STE. The differences of those parameters among the three groups were compared. The correlation between 3D-STE parameters and the running volume was further analyzed.Results:In ST amateur marathon runners, LV EDV was higher compared with controls( P<0.05). Compared with ST and control groups, LV EDV, ESV, and LVM of MET runners were increased(all P<0.05). In addition, compared with control group, GLS of MET runners was increased( P<0.05). The LVEF, GCS, GRS, GAS, twist, and torsion showed no statistically significant differences among the three groups(all P>0.05). In amateur marathon runners LV EDV, ESV, LVM had statistically significant positive correlations with an average weekly running volume and total running volume (all P<0.01). Multivariate linear regression analysis showed that the total running volume was an independent correlation factor in LV EDV of amateur marathon runners (β=0.618, P<0.01). Conclusions:Amateur marathon runners participating in a short term marathon mainly show an increase in LV EDV, the longitudinal systolic function of the LV can be enhanced in the early stage of the marathon.