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Children hospitalized for coronavirus disease 2019 (COVID-19): A multicenter retrospective descriptive study Dear editor: We read with interest the article by Dr. Song R and colleagues in the Journal of Infection titled "Clinical and epidemiological features of COVID-19 family clusters in Beijing, China." 1 , published online in April 2020. The authors presented the epidemiological and clinical features of the clusters of four families and found that SARS-CoV-2 is transmitted quickly in the form of family clusters. Children in the families generally showed milder symptoms. As of April 28, 2020, the coronavirus disease 2019 (COVID-19) caused by the novel severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has been responsible for more than 3.05 million confirmed cases around the world. Early evidence showed that children seemed to be escaping the worst effects of the SARS-Cov-2. 2 However, a recent study indicated children with SARS-CoV-2 infection could be detected in early January 2020 in Wuhan. 3 Another study reported that children are as susceptible to COVID-19 as adults. 4 As the number of children infected with COVID-19 gradually increases, the disease has been documented in infants, children and adolescents, however, limited reports analyzed pediatric patients with COVID-19. Although a recent review has summarized the clinical features and management of infected children, 5 the spectrum of disease of children outside Wuhan are still limited. Therefore, we included 46 children (≤18 years of age) hospitalized with positive real-time fluorescence polymerase chain reaction (RT-PCR) results of throat swabs were included from four tertiary-care hospitals in Guangdong, Hunan, and Hubei Provinces, China between January 20, 2020 and March 9, 2020. Demographic data and clinical features are summarized in Table 1. Details of the laboratory, chest radiological findings and treatment are provided in Supplementary Tables 1-2 and Figure 1. All 46 children cases were non-severe by clinical examination. 29 children (63%) were male, with a median age of 8 years (interquartile range, 4-14 years; range, 7 months to 18 years). 32 children (70%) had at least one infected family member, indicating pediatric patients acquired infections mainly through close contact with their parents or other family members who lived in Wuhan, or had visited there. Unlike adults, no children in this study had comorbidities. 22 children (48%) were asymptomatic at the onset. The most common clinical symptoms were dry cough [12 children (26%)] and fever [eight children (17%)] accompanied by other upper respiratory symptoms, such as nasal congestion and runny nose. Our children cases had no gastrointestinal symptoms, such as nausea, vomiting, and diarrhea. No children had leukopenia and lymphopenia. 20 children (43%) had chest imaging abnormalities, such as unilateral nodular or patchy ground-glass opacities. Recent studies questioned the role of chest CT in the diagnosis of COVID-19 because of biologic

Many recent studies have suggested that bergapten (BP), a class of native compound with numerous biological activities such as anti-resorptive properties, may exert protective effects against postmenopausal bone loss. However, it remains unknown whether BP regulates or improves the osteogenic function of bone marrow stromal cells (BMSCs) in the treatment and prevention of osteoporosis. In our study, BMSCs were cultured in osteogenic induction medium with the addition of BP for 2 weeks and an ovariectomized mouse model of osteoporosis was used to investigate the anti-resorptive effect of BP by gavage administration for 3 months. The concentrations of BP used were 0.1, 1, and 10 μmol/L in vitro and the gavage dose was 20 mg/kg/d. The result of our study indicated that BP promotes the expression of alkaline phosphatase (ALP) by BMSCs in vitro in a dose-dependent manner, as revealed by ALP staining. Runt-related transcription factor 2 and osteocalcin were up-regulated both in vitro and vivo, while osterix and collagen Iα1, assessed by immunofluorescence and immunohistochemistry, were correspondingly raised in the presence of BP in BMSCs in vitro. In addition, a protective effect of BP against ovariectomy-induced bone loss was found by distal femur micro-CT scanning, with improvements of bone metabolism parameters such as bone mineral density, trabecular number, and trabecular separation. Furthermore, WNT/β-catenin signaling was activated in the presence of BP in BMSCs in osteogenic culture. Finally, BP promoted differentiation of BMSCs into osteoblasts by up-regulation of the WNT/β-catenin pathway.

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Background:Previous studies showed that combining apparent diffusion coefficient (ADC) value with the Spondyloarthritis Research Consortium of Canada (SPARCC) index value might provide a reliable evaluation of the activity of ankylosing spondylitis (AS), and that contrast-enhanced (CE) magnetic resonance imaging (MRI) is unnecessary. However, the results were based on confirming only a small random sample. This study aimed to assess the role of CE-MRI in differentiating the disease activity of AS by comparing ADC value with a large sample.Methods:A total of 115 patients with AS were enrolled in accordance with Bath AS Disease Activity Index and laboratory indices, and 115 patients were divided into two groups, including active group (n = 69) and inactive group (n = 46). SPARCC, ΔSI, and ADC values were obtained from the short tau inversion recovery (STIR), diffusion-weighted imaging (DWI), and CE-MRI, respectively. One-way analysis of variance and receiver operating characteristic analysis were performed for all parameters.Results:The optimal cutoff values (with sensitivity, specificity, respective area under the curve, positive likelihood ratio, and negative likelihood ratio) for the differentiation between active and inactive groups are as follows: SPARCC = 6 (72.06%, 82.61%, 0.836, 4.14, 0.34); ΔSI (%) = 153 (80.6%, 84.78%, 0.819, 5.3, 0.23); ADC value = 1.15 × 10−3 mm2/s (72.73%, 81.82%, 0.786, 4, 0.33). No statistical differences were found among the predictive values of SPARCC, ΔSI, and ADC. Multivariate analysis showed no significant difference between the combination of SPARCC and ADC values with and without ΔSI.Conclusions:Using large sample, we concluded that the combination of STIR and DWI would play significant roles in assessing the disease activity, and CE-MRI sequence is not routinely used in imaging of AS to avoid renal fibrosis and aggravation of kidney disease.