Case report: Local bleomycin injection: A possible treatment option for primitive myxoid mesenchymal tumor of infancy.

In recent years, it has been determined that primitive myxoid mesenchymal tumors of infancy (PMMTI) are solid tumors. To date, very few cases of PMMTI have been reported, and there is no consensus regarding treatment. To provide additional references, it is necessary to collect and report the diagnoses and treatment outcomes of related cases. We report the case of a 38-day-old girl who presented with a 5-cm purple tumor in the right shoulder. Upon hospital admission, the patient received an intratumoral injection of bleomycin after diagnosis of a possible lymphangioma. 10 days after the treatment, the tumor began to develop inflammation and necrosis, resulting in a clear demarcation between the tumor and surrounding tissue. Hence, during the second hospitalization, we performed a successful tumor resection. Postoperatively, the tumor was pathologically diagnosed as PMMTI. 3 months after excision, the patient showed no local recurrence on re-examination. To the best of our knowledge, this is the first report of a PMMTI in which bleomycin, or other similar chemotherapeutic drugs, have been injected into tumors. This result offers novel insights into the treatment of PMMTI. Injection therapy with bleomycin and similar chemotherapeutics may result in specific responses to PMMTI, which may help in developing better surgical conditions or improving outcomes in non-surgical patients.

Rotavirus and adenovirus infections in children during COVID-19 outbreak in Hangzhou, China.

BACKGROUND: This study aims to investigate the impact of protective measures and isolation on intestinal infection in children before and after COVID-19 outbreak in Hangzhou, China. METHODS: Data on outpatient visits, intestinal infection visits, and tests of adenovirus or rotavirus from electronic healthcare records were extracted in Children's Hospital of Zhejiang University School of Medicine during the COVID-19 outbreak (January-December, 2020), and be compared with those in 2019 during the same period. RESULTS: We found that pediatric outpatient visits, patients with intestinal infection and its proportion from January to December of 2020 were significantly less than that in the same period of 2019. Furthermore, the numbers of outpatient visits and patients with intestinal infection were the lowest in February and elevated slowly from March to December in 2020. We also found significantly decreased number of completed tests for intestinal viruses, positive cases of adenovirus and rotavirus, positive rate of rotavirus during January-December, 2020. The positive rates of adenovirus from March to September and December of 2020 were significantly lower than the levels of the same period in 2019. The positive rate of rotavirus and adenovirus in all age groups in 2020 is lower than the level of all age groups in 2019. CONCLUSIONS: The outpatient visits and intestinal, rotavirus and adenovirus infections in children significantly decreased during COVID-19 outbreak. Adequate protective measures and isolation in children may help to prevent intestinal virus infections in children.

Case Report: Membranoproliferative Glomerulonephritis, a Rare Clinical Manifestation of Abernethy Malformation Type II.

This report describes an 8-year-old male who presented with clinical manifestations including systemic edema, heavy proteinuria, hypoproteinemia, and persistent hypocomplementemia. Arachnoid cysts and focal nodular hyperplasia were also detected. Imaging examination and renal biopsy were performed, and Abernethy malformation type II with immune complex-mediated membranoproliferative glomerulonephritis was considered the diagnosis. Due to the persistence of embryonic vessels, Abernethy malformation is a rare congenital vascular malformation of the splanchnic venous system, which can be classified as type I (end-to-side shunt) and type II (side-to-side shunt). Abernethy malformation with glomerulonephritis remains extremely rare. In the patient described, glomerulonephritis mediated by immune complex with "full-house" positive immunohistochemistry was confirmed on renal biopsy. In addition, he was treated with glucocorticoids and tacrolimus. Whether surgical treatment is necessary should be determined according to the state of the disease in the later stages. The present case reflects the association between the congenital portosystemic shunt and the renal region and, to the authors' knowledge, may be the first report to describe arachnoid cysts as a symptom of Abernethy malformation.

Epidemiological and virological characteristics of respiratory tract infections in children during COVID-19 outbreak.

BACKGROUND: To investigate the impact of protective measures and isolation on respiratory tract infections in children during the COVID-19 outbreak. METHODS: We extracted data on outpatient visits and respiratory infection visits, and tests of respiratory viruses (adenovirus (ADV), influenza A (FluA), influenza B (FluB) and respiratory syncytial virus (RSV)) from electronic healthcare records in Children's Hospital, Zhejiang University School of Medicine during the COVID-19 outbreak (January-April, 2020), compared with those in 2018 and 2019 during the same periods. RESULTS: We found that outpatient visits in January, 2020 was comparable with those in 2018 and 2019, but decreased by 59.9% (288,003 vs. 717,983) and 57.4% (288,003 vs. 676,704), respectively during the period of February-April, 2020, as compared with the same periods in 2018 and 2019. The total number of respiratory tract infections from January to April 2020 decreased by 65.7% (119,532 vs.348,762) and 59.0% (119,532 vs.291,557), respectively compared with the same periods in 2018 and 2019. The proportion of respiratory tract infections during the outbreak also dropped compared with the same periods in 2018 and 2019 (P<0.001). We also found significantly decreased number of completed tests for respiratory viruses and positive cases of ADV, FluA, FluB, and RSV during February-April, 2020. CONCLUSIONS: In this study, we found that outpatient visits and respiratory tract infections in children significantly decreased during COVID-19 outbreak. Adequate protective measures and isolation in children may help to prevent respiratory virus infections in children.

Hierarchical Conformational Dynamics Confers Thermal Adaptability to preQ1 RNA Riboswitches.

Single-stranded noncoding regulatory RNAs, as exemplified by bacterial riboswitches, are highly dynamic. The conformational dynamics allow the riboswitch to reach maximum switching efficiency under appropriate conditions. Here we characterize the conformational dynamics of preQ1 riboswitches from mesophilic and thermophilic bacterial species at various temperatures. With the integrative use of small-angle X-ray scattering, NMR, and molecular dynamics simulations, we model the ensemble-structures of the preQ1 riboswitch aptamers without or with a ligand bound. We show that the preQ1 riboswitch is sufficiently dynamic and fluctuating among multiple folding intermediates only near the physiological temperature of the microorganism. The hierarchical folding dynamics of the RNA involves the docking of 3'-tail to form a second RNA helix and the helical stacking to form an H-type pseudoknot structure. Further, we show that RNA secondary and tertiary dynamics can be modulated by temperature and by the length of an internal loop. The coupled equilibria between RNA folding intermediates are essential for preQ1 binding, and a four-state exchange model can account for the change of ligand-triggered switching efficiency with temperature. Together, we have established a relationship between the hierarchical dynamics and riboswitch function, and illustrated how the RNA adapts to high temperature.

Solution structure of the RNA recognition domain of METTL3-METTL14 N6-methyladenosine methyltransferase.

N6-methyladenosine (m6A), a ubiquitous RNA modification, is installed by METTL3-METTL14 complex. The structure of the heterodimeric complex between the methyltransferase domains (MTDs) of METTL3 and METTL14 has been previously determined. However, the MTDs alone possess no enzymatic activity. Here we present the solution structure for the zinc finger domain (ZFD) of METTL3, the inclusion of which fulfills the methyltransferase activity of METTL3-METTL14. We show that the ZFD specifically binds to an RNA containing 5'-GGACU-3' consensus sequence, but does not to one without. The ZFD thus serves as the target recognition domain, a structural feature previously shown for DNA methyltransferases, and cooperates with the MTDs of METTL3-METTL14 for catalysis. However, the interaction between the ZFD and the specific RNA is extremely weak, with the binding affinity at several hundred micromolar under physiological conditions. The ZFD contains two CCCH-type zinc fingers connected by an anti-parallel ß-sheet. Mutational analysis and NMR titrations have mapped the functional interface to a contiguous surface. As a division of labor, the RNA-binding interface comprises basic residues from zinc finger 1 and hydrophobic residues from ß-sheet and zinc finger 2. Further we show that the linker between the ZFD and MTD of METTL3 is flexible but partially folded, which may permit the cooperation between the two domains during catalysis. Together, the structural characterization of METTL3 ZFD paves the way to elucidate the atomic details of the entire process of RNA m6A modification.